key: cord- - iwgebvp authors: siegel, frederic r. title: disease protection in sea coast (and inland) cities: problems in dense populations with shantytowns/slums date: - - journal: adaptations of coastal cities to global warming, sea level rise, climate change and endemic hazards doi: . / - - - - _ sha: doc_id: cord_uid: iwgebvp as discussed earlier in this book, there are sea coast cities worldwide that are at risk from floods, storm surges, and extreme weather conditions such as wind-driven high category hurricanes (typhoons, monsoons), or drought and heat waves, plus along pacific ocean coasts, earthquakes and tsunamis. a municipality and its public health services have to be prepared to adapt to their preparations to deal with what contemporary experiences and history reveal are the most likely physical hazards and diseases to impact it. the two main preparatives are first to be able to care for the injured during a hazard event at well-staffed and supplied hospitals and medical clinics or field hospitals. the second is to fill the basic needs of affected populations with clean water, food, shelter, toilets, waste collection, and if necessary power restoration. these primary responses will help to reduce the chance of an onset and spread of disease. it is important to activate search and rescue teams help citizens isolated or trapped by the event that did not or could not evacuate such as in the case of extreme weather and flooding. in addition, where there have been deaths, bodies should be recovered and interred as soon as possible in order to prevent sickness that might originate from them. for instances of collapsed structures with people trapped inside, equipment that can move debris and rescue people or recover the deceased is necessary as would be the case for less common strong earthquakes as well as some extreme storm events. what was just described may be a good template to follow, but in reality, many sea coast cities in developing and less developed countries do not have the resources to cope with severe hazards that might impact them. here, the world health organization and developed nations, large and small, have sent in personnel, supplies, and equipment to help an impacted sea coast city (or inland city) in the past and will surely continue to do so in the future. as discussed earlier in this book, there are sea coast cities worldwide that are at risk from floods, storm surges, and extreme weather conditions such as wind-driven high category hurricanes (typhoons, monsoons), or drought and heat waves, plus along pacific ocean coasts, earthquakes and tsunamis. a municipality and its public health services have to be prepared to adapt to their preparations to deal with what contemporary experiences and history reveal are the most likely physical hazards and diseases to impact it. the two main preparatives are first to be able to care for the injured during a hazard event at well-staffed and supplied hospitals and medical clinics or field hospitals. the second is to fill the basic needs of affected populations with clean water, food, shelter, toilets, waste collection, and if necessary power restoration. these primary responses will help to reduce the chance of an onset and spread of disease. it is important to activate search and rescue teams help citizens isolated or trapped by the event that did not or could not evacuate such as in the case of extreme weather and flooding. in addition, where there have been deaths, bodies should be recovered and interred as soon as possible in order to prevent sickness that might originate from them. for instances of collapsed structures with people trapped inside, equipment that can move debris and rescue people or recover the deceased is necessary as would be the case for less common strong earthquakes as well as some extreme storm events. what was just described may be a good template to follow, but in reality, many sea coast cities in developing and less developed countries do not have the resources to cope with severe hazards that might impact them. here, the world health organization and developed nations, large and small, have sent in personnel, supplies, and equipment to help an impacted sea coast city (or inland city) in the past and will surely continue to do so in the future. disease control after a natural disaster often means initially dealing with diarrheal diseases (dysentery) from the ingestion of contaminated water or food, and lack of sanitation facilities (toilets, hand-washing stations). it may mean dealing with cases of the infectious diseases like cholera (bacterium vibrio cholera) or typhoid (bacterium salmonella typhi) that originate from contaminated water or food or from contacts with cholera or typhoid carriers. to prevent a spreading epidemic status means making safe water and food, sanitation and hand-washing posts available. in the case of cholera, an epidemic may be avoided by isolating the cholera carriers and treating them (with hydration and antibiotics) or oral cholera vaccines where the disease is endemic until the threat of spread is under control. during march - , , the monsoon idai flood ravaged beira, mozambique, a sea coast city of , people, and tracked inland into areas of zimbabwe and malawi flooding them and killing a total of over people. in beira, the drinking water supply and the sewage infrastructure were damaged. cholera cases were diagnosed and the disease spread rapidly with over cases identified with deaths by the april . the who assembled more , doses of cholera vaccine (oral) and starting april delivered more than , initial doses to beira citizens and those in other affected populations, but only about weeks after the disease was first diagnosed. a second inoculation weeks later gives full protection from the disease. adaptation would require vaccine storage stations set up in regions where outbreaks of endemic and other infectious diseases occur so that those that can be controlled by vaccination could be serviced more rapidly than was the case in mozambique. in the above section, infectious diseases that could follow natural disasters that affect sea coast cities were discussed. in this section, infectious diseases that can affect sea coast cities by developing from within or those that are carried in from outside sources are considered. these would be water-and food-borne contaminants and vector-borne bacteria/viruses (by insects, animals, humans). important factors that have to be considered by public health personnel in sea coast cities in order to be prepared to deal with disease include a location's latitude and elevation as they influence climate (temperature and humidity). important sea coast cities are located in most geographic climatic zones. as such, and based on a history of urban health problems, their populations may be susceptible to one or more than one infectious disease that public health services should be prepared to treat. six principal climate zones (mediterranean, tropical, arid, temperate, polar, and mountainous) are classified on the basis of average monthly temperature and precipitation. temperature and precipitation are determined in grand part by latitude, altitude/landform, and the influence of surface and subsurface ocean currents flow paths, location of mountains and their elevations, and seasonal wind directions. the principal zones are a simplification of a zone classification, each with sub-zones (table . ) [ ] . missing from this classification is a mountainous one because with their masses and elevations they establish their own micro-zones and affect weather patterns of some of the other zones. sea coast cities in a similar stage of economic development and in the same climate zones are likely to have exposure to a similar group of endemic infectious diseases. for example, in southeast asia, jakarta, bangkok, and ho chi minh city, are hot ( °c) with higher humidity ( % rh) and have endemic infectious diseases that originate from contaminated water and food, and those that originate from vector-borne carriers. country reports show that in the endemic infectious group, all live with the threat of bacterial diarrheal diseases, and two cities live with the threat of hepatitis a and typhoid fever. in the second group, the three cities have exposure to dengue fever and malaria while two are threatened by japanese encephalitis, and one with hiv/aids and tuberculosis. in africa, mombasa, kenya in east africa, population , and luanda, angola in west africa, population . million, are located relatively close to the equator ( ° ′s and ° ′s, respectively) and have similar temperatures of - °c and - % relative humidity defining their mediterranean/sub-tropical to hot humid tropical climates. however, unlike the southeast asian sea coast cities with similar infectious disease burdens cited above, mombasa and luanda infectious disease burdens differ greatly. mombasa residents are at risk from malaria, tuberculosis, hiv/aids and recently from a resurgent occurrence of polio, measles, and kanazaar (parasitic disease leishmania donovani). luanda, angola residents are at risk from yellow fever, malaria, typhoid fever, and hepatitis a. mombasa, an important kenyan port city also serves uganda, rwanda, the eastern region of the dr congo. this put the mombasa population at risk of infectious diseases that may be carried from those countries by people or products. this possibility for infectious disease transfer was supported when public health personnel recently identified an ebola strain in kenyans who visited west africa. the west african region had suffered an ebola epidemic during - . the disease likely began in a village of southeast guinea as a young boy infected by bats (bushmeat) was carried by exposed villagers to its capital and port city conakry (population . + million). the ebola virus was spread by carriers to the liberian capital and port city monrovia (population million with doctors), and to the sierra leone capital and port city freetown (population + million). the world health organization, medical teams and ngos from other nations worked to stop the epidemic but only after more than , died and more than , were infected and saved. an as-yet unapproved ebola vaccine was used here and was instrumental in halting the spread of the ebola virus. major sea coast cities in south america and the indian sub-continent have similarities and differences of infectious disease risks as do the sea coast cities mombasa and luanda cited above. public health services staffed with appropriate personnel, supported financially, with medicine stocks plus who vaccination stores can be prepared to use them to halt the spread of an infectious disease to prevent an epidemic or to deal with an epidemic that may develop. on august , , there was an outbreak of zaire ebola virus in north kivu province of the dr congo that spread to ituri province. in march, , who reported that there were more than cases and deaths. the public health ministry medical experts identified the disease, did contact tracing, contained and treated infected people, and worked to educate the threatened populations of the risk of not reporting ebola cases, and unsafe burial practices (touching and washing the dead) that is meeting cultural resistance. as important in dealing with the epidemic was the acceptance of the use of the experimental ebola vaccine that helped stop the spread of the ebola disease in west africa a few years earlier. the vaccine was given to people who had direct or indirect contact with people with the disease. however, the application of the ebola vaccine and a halt in the rise of infections has been hampered by armed group violence and unsafe burial practices. the disease is recurrent in the dr congo with ten outbreaks since the discovery of the disease in [ ] . the hope is that it will not become entrenched. one adaptation to infectious disease prevention in this time of ready transnational transport of people globally via sea, air, and land is vaccination control. vaccinations against infectious diseases keep a nation healthy and productive. a low rate of vaccination in a country or regions for years on end can be damning to its citizens and to people where they travel within that country or internationally. the who warns that vaccine hesitancy is one of the top ten global threats of . vaccination hesitancy can be the result of personal philosophical or religious beliefs that allow parents to opt out of this protection for their children as in the united states where there have been major measles outbreaks in eight states and reported cases in other states. in many of these states legislatures are proposing laws to minimize exemptions to measles vaccination requirements for children of school age. a judge in brooklyn, new york, following a serious outbreak of measles in children of a religious sect during april, , mandated application of the mmr measles vaccine (including mumps and rubella) to all their children to protect the general public. this was done over the religion leaders objections to vaccinations. during , europe ( countries) reported that measles killed children and adults of the , people that contracted the measles virus due in part to a vaccination rate (< %) less than the % who deems necessary to prevent epidemics and in part to easily travel between countries. in a recent deadly outbreak, madagascar is working to contain a measles epidemic that began in september, and by february, had killed more than people ( % children to age ) and infected more than , persons. this epidemic is the result of a low immunization rate for many years and has spread throughout the country including madagascar's most important seaport, toamasina, and other ports of entry. this, in spite of the fact that a safe and effective vaccine, has been available for the past years but whose application has not been mandated by the national government. travelers from madagascar to other countries are potential carriers for about weeks ( days before a rash appears, plus days during the rash, and for days after the rash disappears). for this reason, the vaccination history of people entering a sea coast city or other ports of entry who come from or have passed through areas that are suffering or have suffered infectious disease events is important. this would require the collaboration of immigration officials who would be charged with checking the vaccination cards of people (ship personnel, tourists, immigrants, and asylum seekers) at sea coast city ports of entry. the same would be true for other ports of entry. it may require making spot checks of, for example, fever or an observational feature (sweating, paleness) of arriving passengers from specific locations suffering from outbreaks of infectious diseases. this was the case by fever checks in airports and other points of national entry after china revealed the spread of the sars (severe acute, respiratory syndrome) infectious disease during - . non-communicable diseases whether in highly and densely populated sea coast or inland cities can sicken and kill citizens. the focus on the causes of noncommunicable diseases (ncds) that are responsible for million of premature deaths annually and a far greater number of debilitating sicknesses has been on behavioral and metabolic causes and how to reduce their threats to societal health and its effect on city and national economies. these causes include tobacco use, alcohol abuse, poor nutrition, lack of exercise, obesity, and hypertension. of the million premature deaths cited above, ~ million are in low and middle income countries. seventy-nine percent of the ncds are attributed to cardiovascular disease ( . million), cancer ( million), respiratory disease ( . ) million, and diabetes ( . million). public health education programs have to be continually implemented to reduce harmful behavior and causes [ ] . to this point in time, not enough attention has been given to pollution as a principal factor in ncds illnesses and even premature deaths and their socio-economic consequences [ ] . these are often expressed by a calculation of dalys (disability adjusted life years), the total number of years lost to illnesses, disability, or premature deaths in a given population for a certain disease or disorder [ ] . this can be a serious problem in high population sea coast and inland cities with high densities of citizens especially when there are edge neighborhoods with poor and marginalized people living in shantytowns/slums with unsafe water, lack of toilets, and problems with garbage/waste collection. the loss of productivity because of dalys lowers gdp levels by up to % annually, especially in low middle income countries (incomes of us$ to us$ ), such as bangladesh, egypt, india, indonesia, pakistan, and vietnam. cities are most affected because they account for % of global economic business [ ] . pollution is a bane of humanity. air, water, soil, and food pollutants contribute to the premature deaths of millions citizens and sickens many millions more from ncds. pollution-caused diseases accounted for about million premature deaths in or % of all deaths globally (> million). of the million premature deaths, about % of these (e.g., cardiovascular disease, copd) were from pollutioncaused ncds, mainly in low income and low middle income countries [ ] . pollution is most damaging to people and economies where environmental laws protecting people and ecosystems from pollution have not been instituted or if laws have been passed but are not enforced. pollution does not distinguish between sea coast and inland cities but as noted above is most damaging where there are high and dense populations breathing, drinking, and eating pollutant bearing matter. the effect of ingestion of pollutants that cause ncds is not instantaneous but acts slowly over a period of time gradually attacking the normal functioning of body organs as pollutants access and bioaccumulate in them. pollution can be greatly mitigated in three ways: ( ) taxation has been effective in minimizing/eliminating the mass of pollutants emitted into the atmosphere or discharged into waterways or onto soils; ( ) investment in pollutant capture and control equipment and safe disposal of the captured pollutants; and ( ) legislation enforced by the threat and actions of closure of a pollutant-generating operation, by fines, or by incarceration of responsible individuals. of the ~ million premature deaths caused by pollution, ~ million are from indoor air pollution ( . million) and outdoor air pollution ( . million) [ ] . there are . million people that die annually from water pollution (bacterial, viral, heavy metals) and . million from soils polluted with heavy metals and toxic chemicals (e.g., pesticides) ingested through foods. from an economic perspective, pollution frequency costs in the range of - % of a nation's gdp and for some this exceeds what they receive in development aid [ ]. diseases that originate from indoor air pollution include stroke, coronary artery and ischemic heart diseases, chronic obstruction pulmonary disease (copd), acute lower respiratory infections in children, and lung cancer. outdoor air pollution diseases are much the same but with less coronary artery disease. sickness and deaths from indoor air pollution are the result of poor or no venting of gases and fine size particulates (< . - μm) from the fuel used (e.g., soft coal, charcoal, wood, dried animal waste) for cooking and/or heating. improved venting of indoor generated pollutants to the outside can reduce sickness and deaths especially for the more susceptible old people and small children but will add these toxins to outdoor air pollution. the effects of indoor air pollution can be eliminated by bringing natural gas to homes for cooking and heating and proper venting of emissions. this solution is lacking in some major sea coast and inland cities with highly populated shantytown/slum in inner city or edge neighborhoods. outdoor air pollution comes from multiple sources such as coal-burning power plants, various industries, vehicular traffic, and construction. these sources, individually or in consort, emit or raise fine size particulates (< . - μm), and other toxic emissions into the air that include sulfur dioxide, nitrous oxide, and heavy metals (e.g., lead [pb], mercury [hg], arsenic [as], cadmium [cd], and others). these toxic emissions may be inhaled or deposited onto soils or into waters where they can enter a food chain via agricultural crops (e.g., cd in rice) and food fish (e.g., hg in tuna, swordfish, king mackerel). under some meteorological conditions, toxic emissions from industries and vehicular emissions will contribute to a sickening or killer smog. air pollutant abetted diseases are most prevalent among major sea coast and inland cities with upwind nearby major industrial development and in shantytown/slum populations vs. economically more advantaged populations. the mandated use of pollutant capture and control technologies can mitigate the emissions of toxins from industrial sources cited and together with the inclusion of catalytic converters on vehicles can reduce the number of premature deaths abetted by outdoor air pollution. as cited previously, taxation of emission masses can mitigate the problem as can fines, plant closure until facilities becomes compliant with government legislative mandates, or the threat of imprisonment of plant owners [ ] . several major sea coast cities with high populations with very high and relatively high densities in developing countries suffer greatly from air pollution. these include dhaka ( , people/km ), mumbai ( , /km ), abidjan ( , /km ), kolkata ( , /km ), jakarta ( /km ), ho chi minh city ( /km ), bangkok ( /km ), guangzhou ( /km ), zhangjiang ( /km ), tianjin ( /km ), and ningbo ( /km ). in some of these cities, the air pollution threat is elevated by high numbers of poor populations living in shantytowns/slums where densities are higher than the average for a city and where the health status of a population is not as resistant to sickness and disease as it is in economically advantaged inner city populations. for example, in . because of the concern for citizens health and the economic losses from workdays lost or even years of an individual's contribution to a nation's development lost, municipal governments have been monitoring air pollution and identifying specific sources of air-borne toxins. in some cases, they are enforcing existing legislation or carefully planning legislation with enforcement powers that mandate the use of best available technologies at all toxic emissions sources and safe disposal of the captured pollutants. if enforcement is applied, it will greatly reduce toxin loading of pollutants into the atmosphere and hence reduce the risk to the health and premature deaths of great numbers of people. this will be effective only if enforcement of laws curbing air pollution is not just an empty threat because of a nation's drive for continued economic development or because of a culture of corruption. water pollution comes from the atmosphere as rain precipitates toxins from industrial emissions, especially coal-fired power plants and other sources into waterways or onto land where contaminants may run off into waterways. water pollution comes as well from toxins in industrial effluents discharged onto land that can runoff into streams and rivers. rainwater or streams that flow through talus piles of mine wastes can dissolve out heavy metals and carry them overland into waterways. acid mine drainage from abandoned and functioning operations contaminates streams/rivers into which it discharges. bacterial pollutants from human wastes where toilets are not used or where the wastes are collected but not treated can pollute waterways as do wastes and agricultural chemicals as runoff from farmland and commercial animal husbandry (e.g., cattle feed lots, chicken production). the toxin runoff, whatever the source(s), affects not only humans but ecosystems and their natural resources that are important to people. contaminated waters can be cleansed to drinking standards by passing them through a treatment plant before distribution to consumers. toxin-bearing surface runoff cited above can also seep through a surface cover into aquifers and contaminate groundwater. under some conditions, groundwater can dissolve heavy metals that may be in aquifer rocks thus polluting water downflow from where the toxic metals originate. as with surface sources of water, polluted groundwater can be treated to remove a heavy metal pollutant or more than one, or other chemicals before being released for human use (drinking, cooking, personal hygiene) or for irrigation of food crops. the sickening of citizens in well-populated sea coast cities from ingestion of pollutants in unsafe drinking (and cooking) water is a grave concern especially in poor neighborhoods that lack access to clean water vs. economically advantaged neighborhoods that receive treated clean water [ ] . sea coast and inland cities with large and growing populations (e.g., in the millions) obtain much of their foods from distant national and international sources. the reality is that some agricultural products (e.g., grains, vegetables, tobacco) may contain toxins taken up from soil or irrigation water polluted by human activities. these include heavy metals and pesticides/herbicides. if contaminated products are consumed over time, their toxin contents can build up in body organs (e.g., kidneys, lungs) and cause ncds (see sect. . ). toxin build up can also disrupt the normal functioning of nervous and cardiovascular systems, and renewal of skeletal matter. the ingestion of human generated soil/food pollutants can cause ncds [ ] [ ] [ ] . in addition to soils being polluted by industrial and agricultural sources, soils can have natural high concentrations of potentially toxic metals. if a rock contains heavy metals (e.g., black shale) and a soil forms from it as it degrades and decomposes, contaminant metal(s) may be retained in the soil. one pathway to humans is ingestion of one or more of the potentially toxic metals taken up by agricultural crops (food or a non-edible product such as tobacco) being grown in a heavy metal polluted soil. another pathway is from rainwater that seeps through a naturally contaminated soil that reacts with it to release a heavy metal that seeps through the soil into an underlying aquifer. here, the path is toxic metal from rock to soil to agricultural products or drinking/cooking water that can do the same harm to the human body as noted in the previous paragraph by bioaccumulation in and damage to vital organs and also cause medical symptoms and the onset of a ncd. examples of ncds caused by heavy metal poisoning abound in the literature [ , ] . whether a ncd will develop from ingestion of a potently toxic metal depends on several factors. these are the dose absorbed by a body, the route and duration of exposure to chemical species that can cause chronic or acute illness, age, gender, genetics, and health conditions of exposed individuals. perhaps most studied in recent years are cadmium (cd), lead (pb), arsenic (as), mercury (hg), and chromium (cr). there are natural sources of potentially toxic metals (e.g., rocks containing arsenic-bearing minerals, ores, volcanic gases, and particulates). however, great masses of the heavy metal pollutant load in the atmosphere, water bodies, and soils come from human sources. these include industrial operations emissions and effluents, especially from coal-fired power plants, mining and smelters, and factories that manufacture batteries, pharmaceuticals, fertilizer and biocides, paper, pulp, and wood preservatives, among others. sources for each metal or a group of metals that are thought to be linked to an epidemiology-defined disease node can be traced by following geological/geochemical principles used in the search for mineral deposits. governments can then take action to greatly reduce or eliminate the source(s). the fundamental question exists as to whether a government should make regular spot analyses to determine if there is a risk of heavy metal poisoning from agricultural food stuffs. in theory, the answer is yes. realistically, however, analyses would be done but only after a heavy metal was identified fortuitously or if public health professionals detected symptoms of heavy metal poisoning in a population. heavy metals are important to industrial development as well as to human health. there are heavy metals that are essential micronutrients for the optimal functioning of biological processes and organs in humans in a quantity of a few milligrams (mg) or micrograms (μg) daily. these are fe (iron), zn (zinc), co (cobalt), as (arsenic), cr (chromium), cu (copper), mn (manganese), mo (molybdenum), se (selenium), and v (vanadium). however, these may become toxic if ingested and bioaccumulated over time to higher concentrations than are necessary to satisfy nutritional needs. as noted in a previous paragraph, heavy metals that are most toxic to humans (+ animals and ecosystems) if ingested regularly in water and/or food are as, pb, hg, and cd. these metals can bioaccumulate in a body and have toxic effects on different vital organs. in addition, they can interfere in the functioning of essential elements and their metabolic processes. these four heavy metals have been well-studied by toxicologists and other scientists for sources, mobility in ecosystems, and toxic effects. their maximum allowable world health organization limits via oral intake in μg/day are pb ( ), hg-inorganic ( ) , as-inorganic ( ) , and cd ( ) [ ] . in the past and the present, old established sea coast cities have been centers of industrial development ofttimes within and/or upwind and upriver of cities. this, and increasing urbanization as populations grow, fueled increased utility and transportation needs. the release of heavy metals from industrialization, utility sources, and vehicles into a city environment and associated ecosystems on land and in the oceans can be an inherited legacy or existing danger to public health through bad air and contaminated water, soils, and foods. how sea coast cities (and inner ones) and national governments have adapted to mitigate toxic metal pollution is reflected in the health status of their populations. lead represents an inherited legacy that is an existing health threat in and surrounding old homes from pb in drinking water that passes through utility and home pipes containing pb or pipes joined with pb-containing solder. this problem is being addressed by replacing the pipes, by regularly flushing and cleansing city water pipe networks, and by meeting who standards at treatment facilities. lead bearing soil dust from vehicular sources has been basically eliminated since the phasing out of leaded gasoline that began in the s and s with the introduction of catalytic converters. however, inherited pb in soils can be a health hazard. a city may opt to replace a soil, cover it, or otherwise remediate it especially at playgrounds. cities were early in adapting to the pb-based paint problem by recommendations that the amount of pb in interior and exterior paint be reduced to < % and subsequently to < . % in . the un and world bank aim to eliminate its use in . a reasonable recommendation to deal with the millions of homes with pb-based paint is not to strip it off thus releasing toxic dust and chips to the air and surrounding soil but rather to repaint over it when the paint starts flaking. lead reduction programs are essential to protect babies and small children who are especially threatened by pb poisoning if they regularly ingest pb through drinking water, hand to mouth transfer of contaminated soils, or chewing on flaking paint. poisoning manifests itself by brain damage that can result in behavioral problems, learning deficits, and lowered iq. cadmium is an existential health danger, a known carcinogen. a principal source of the toxin is in rice grown in cd-rich soils or irrigated with cd-rich water. a public outcry arose in in guangzhou, china, a port city of . million people, when a report revealed that the rice tested in of samples from local markets had cd concentrations above china's national food safety standards. citizens were upset because of the knowledge that a long-term bioaccumulation of cd in the body had . heavy metal pollutants harmful to people and ecosystems been linked to chronic kidney disease/failure, the bone diseases osteoporosis and osteomalacia, diabetes, lung disease, impairment, cardiovascular disease, and cancer [ ] [ ] [ ] . rice is a staple food for close to half the world's population (~ . billion people) especially for poor populations in low and low middle income countries and its purity has to be assured. about % of the consumption is in asia, with a rising demand in africa and latin america, regions with a great number of commercially important sea coast cities. awareness of the potential problem has resulted in spot checks of rice crops to assure their purity. scientists are studying how to reduce the bioavailability of cd in a soil (paddy or not) to growing plants rice grains, by adjusting the ph of the growing medium [ , ] . geneticists that have improved micronutrient contents in rice crops and the plant tolerance to pests and herbicides are researching low cd-accumulating rice cultivars growing in cd-rich soils. these may reveal a gene that damps cd uptake. once identified, genetic engineers can modify receptive rice species that will greatly reduce uptake of soil cd yet maintain their nutritional values. cadmium can also access a body by inhaling cigarette smoke from tobacco grown in cd-rich soils. arsenic has been shown to be the cause of chronic and ncds in many countries with commercially important and high/densely populated port cities, especially in bangladesh, india, pakistan, thailand, vietnam, taiwan, and china. contaminated drinking water and cooking with untreated or insufficiency treated aquifer water is a principal source of the toxin. the as may develop within an aquifer as conditions change with water drawdown during growing season permitting oxidation and release from a mineral in aquifer rock into the water as either the oxidized chemical species arsenite (as + ) or arsenate (as + ). both species can be toxic if enough is ingested but the (as + ) form is times more toxic [ ] . the chronic response to as poisoning may be the appearance of lesions as pinkish to tan or skin colored papules and keratosis, an epidermal wart-like growth. acute afflictions caused by the longterm as bioaccumulation are cancer of the lungs, liver, bladder, or skin [ , ] . the world health organization warned that more than million people are at risk of as poisoning from aquifer water. water treatment facilities can eliminate this problem if installed, supplied with necessary cadres and chemical supplies, and maintained with a clean water distribution network that reaches all of a population. mercury in food fish is an existing public health threat. mercury emitted into the atmosphere from industrial sources, especially coal-fired power plants, rains into the oceans where microorganisms in the marine food chain convert it to the very toxic methyl mercury form (ch hg + ) [ ] . this chemical bioaccumulates in prey of large predator food fish (e.g., king mackerel, swordfish, tuna, tilefish, orange roughy, shark, marlin, and escolar) that further concentrate it to levels that can harm humans that regularly eat them. shellfish bioaccumulate the toxin as well. sea coast populations include much fish/shellfish in their diets, especially poorer citizens that count on fish/shellfish for % of their protein nourishment and % of their calorie intake. mercury intake can be especially dangerous to pregnant women or women that breast feed their infants because the ch hg + can pass to a growing fetus or an infant and cause neural damage. in adults, hg poisoning can manifest itself as tremors, memory problems, depression, or diminished hearing and vision. governments recommend how much hg accumulating fish meat is safe to eat. for example, canada recommends that pregnant women limit their intake to g/month ( / oz), youngsters - years old eat no more than g/month (~ / oz), and children - years old eat no more than g/month (~ / oz). these values vary with the food fish eaten [ ] . lastly, it should be noted that there is a possible legacy source of heavy metal toxins or other pollutants: buried/hidden toxic wastes. these are disposal sites left by long gone industries in or near long established sea coast (and inner) cities. as urban centers grow to accommodate expanding populations ( . billion more people in than in ), perhaps million added to port cities, areas to be urbanized should first be assessed to assure that no buried/hidden toxic waste disposal sites are present that could, over time, release toxins into an inhabited zone and pose a danger to people. if detected, such sites must be cleaned up before habitation is allowed. köppen climate classification ebola virus epidemic in war-torn estern dr congo pollution and non-communicable disease: time to end the neglect world bank group, independent evaluation group ( ) towards a clean world for all: an ieg evaluation of the world bank group's support for pollution management ambient air pollution: a global assessment of exposure and burden of disease. who, geneva, p. apps.who world urban areas (built up urban areas or world agglomerations) guidelines for drinking-water quality heavy metals, toxicity and the environment. a review toxicity, mechanism and health effects of some heavy metals cadmium stress in rice: toxic effects, tolerance mechanisms, and management: a critical review heavy metals causing toxicity in animals and fishes high cadmium levels found in guangzhou rice, south china strange osteomalacia by pollution from cadmium mining cadmium (cd) stress in rice; photo-availability, toxic effects and mitigation measures -a critical review effective method to reduce cadmium accumulation in rice grain worldwide occurrence of arsenic in groundwater global mercury emissions to the atmosphere from anthropogenic and natural sources health canada ( ) mercury in fish. consumption advice: making informed choices about fish key: cord- -pixbry c authors: eggo, rosalind m.; cauchemez, simon; ferguson, neil m. title: spatial dynamics of the influenza pandemic in england, wales and the united states date: - - journal: j r soc interface doi: . /rsif. . sha: doc_id: cord_uid: pixbry c there is still limited understanding of key determinants of spatial spread of influenza. the pandemic provides an opportunity to elucidate spatial determinants of spread on a large scale. to better characterize the spread of the major wave, we fitted a range of city-to-city transmission models to mortality data collected for population centres in england and wales and cities in the us. using a gravity model for city-to-city contacts, we explored the effect of population size and distance on the spread of disease and tested assumptions regarding density dependence in connectivity between cities. we employed bayesian markov chain monte carlo methods to estimate parameters of the model for population, infectivity, distance and density dependence. we inferred the most likely transmission trees for both countries. for england and wales, a model that estimated the degree of density dependence in connectivity between cities was preferable by deviance information criterion comparison. early in the major wave, long distance infective interactions predominated, with local infection events more likely as the epidemic became widespread. for the us, with fewer more widely dispersed cities, statistical power was lacking to estimate population size dependence or the degree of density dependence, with the preferred model depending on distance only. we find that parameters estimated from the england and wales dataset can be applied to the us data with no likelihood penalty. spatially explicit models are critical to understanding the spread of infectious diseases through populations and to better inform policy aimed at controlling that spread. indeed, recent outbreaks of communicable diseases in human populations have triggered a series of studies addressing the spread of directly transmissible infections at a country level [ - ] . identifying a possible backbone of high probability transmission paths through populations may underpin the development of effective interventions to curtail spread on the population network [ ] . for example, in human diseases, spatial models and microsimulations can quantify the possible role of border control, quarantine or transport reductions in curtailing local and international spread [ - , - ] . spatial microsimulation models like these are critical to making effective policy decisions. spatial models also allow limited control resources to be used where they might be most effective. for instance, during the initial stages of an outbreak of a new virus, disease incidence tends to occur in spatial clusters with occasional long-range infection events [ ] . as case numbers increase in the start location, the frequency of long-range infection events increases. this spatial pattern was seen during the early stages of the influenza pandemic in mexico, leading to local foci seeded by long-range interactions to other countries [ , ] . however, those epidemic models rely on a set of structural assumptions that need to be validated from data. a basic assumption of many spatially explicit transmission models is that flows between urban centres are a function of the distance between them and their attributes, most notably residential or worker population sizes [ , ] , resulting in a so-called gravity model. however, for human diseases, little work has been done to validate the underlying assumption that human travel patterns are predictive of the spatial spread of diseases. early models of spatial coupling in ecology assumed that connectivity between populations was inversely related to the distance between them [ ] . for people (and most animals) distance-based coupling is too simplistic an assumption. movement between large population centres is disproportionately more frequent than between smaller ones [ ] . xia et al. [ ] found that a distance-only model for spread of measles in the uk was a poor fit to weekly measles data from england and wales from to . the gravity model used in that study measures connectivity between population centres as a function of distance and a function of the population sizes of the origin and destination cities. however, measles is a childhood disease, and so the spatial dependencies of the host are different than for infections that affect both adults and children, such as pandemic influenza. gravity models and other spatial interaction models allow understanding of the movement of populations from one location to another in the absence of movement data. models, once validated, can predict modifications in connectivity when populations grow or shrink, when workflows vary owing to economic changes or if restrictions are imposed on one city and not others. this is in contrast to movement surveys, which are context-specific and provide a snapshot of the movement habits of a population. the strength of connection between cities may be density independent, that is, the sum of connectivity of a city to all its neighbours does not depend on the number of neighbours that city has. in contrast, density-dependent connectivity links two cities at a strength solely determined by the sizes of those cities and their distance apart, so that the total connectivity of any one city scales with the number of close neighbours. density-independent transmission gives a total force of infection, which is independent of the remoteness of the population, whereas density-dependent transmission will cause populations with many neighbours to experience a higher force of infection than those cities that have few neighbours. thus, a densitydependent model will predict that isolated populations are less likely to become infected than populations with many neighbours, or few very large neighbours. the concepts of density dependence/independence have not only been used to model interactions between cities; they have also been used extensively in individual based models of disease spread. most past studies tend to assume either density dependence (e.g. for animal epidemics; [ , ] ), or density independence (e.g. for most human diseases) [ , ] . here, we explore the extent to which city-to-city (rather than individualto-individual) contacts are density independent by constructing a model that can capture intermediate levels of density dependence. in this paper, we analyse mortality datasets from england and wales and the united states from to to examine the pattern of spatio-temporal spread and the extent to which gravity models can reproduce observed trends. the pandemic constitutes a rare example of a well-documented epidemic in a largely susceptible human population, where the high mortality gives a clear incidence signal, and is therefore a rare opportunity to validate models of epidemiologically relevant geographic coupling. we examine the effect of city-specific characteristics (e.g. location, distance from other cities, population size and the number of influenza-related deaths) on the pattern of spread seen. we also investigate the impact of the distribution of cities in each country. the analysis provides further insight on the spatial variation in the spread of the influenza pandemic at a country level, much of which remained unexplained in past studies [ , [ ] [ ] [ ] . the pandemic h n virus appears to have entered the general population of the uk and us in the spring of causing a reportedly mild disease [ ] . this early wave was associated with increased mortality, but was probably only noticed because influenza is rare in summer. this epidemic waned later in the summer, but infection reappeared in the autumn with much increased mortality. it is unclear whether the viruses causing the spring and summer waves were closely related, but there is increasing evidence that the spring wave gave immunological protection against the autumn wave at a population level [ , ] . by september , the pandemic was a prominent global phenomenon. the autumn wave was virtually universal, albeit with some variation between countries in precise timing. in both the uk and the us, a third wave of influenza occurred in early although with greater heterogeneity in mortality rates between cities [ , , ] . us cities had more variation in the severity of the major wave than the uk, probably in part because some enacted more stringent non-pharmaceutical interventions to mitigate the epidemic [ , ] . the third wave was less pronounced in us cities than in england and wales, again perhaps partly because of the effect of interventions. the england and wales dataset shown in figure a was published in the supplement to the st registrar general report [ ] . it provides weekly death counts and annualized mortality rates per from county boroughs, municipal boroughs, urban districts and three unclassified urban centres in england and wales, for a week interval, june - may . the first weeks are designated as wave , the next as wave and the last as wave . our analysis focuses on the second wave because it occurred in all cities (unlike wave ) and because recording of mortality had begun in all cities before its arrival (unlike wave ). in addition, reporting of influenza and influenza-related mortality changed between the first and second waves. point locations of all urban centres were determined from the current or historical records, with euclidean distance used to quantify inter-centre separation. further information is given in the electronic supplementary material. we compiled a us city dataset (figure b) from five publications reporting the weekly health index as collated by the bureau of the census [ , [ ] [ ] [ ] [ ] . it covers the period september to march and contains weekly pneumonia and influenza death counts for cities in the us. the us data therefore covers a period of two waves, with not all cities experiencing the later wave. there is very good agreement between different sources where they overlap. we used the euclidean distance between cities (accounting for curvature of the earth) to measure separation. further information is given in the electronic supplementary material. the analysis requires an estimate of when each city became infected to allow potential sources of that infection to be identified. for each city infected in week t, the candidate infectors are those infected in any week before t. we define the infection week of city i, t i , to be the first that meets a set of conditions on mortality in weeks t i þ , t i þ and t i þ . we use mortality values ahead of t i to include the time from infection to death. a week could be designated the infection week if either (or both) of two sets of criteria were met for mortality in the following weeks. the first set of criteria required the mortality rate in week t i þ to be above a certain threshold, to have increased in t i þ and to be above a higher threshold in t i þ . these criteria are intended to ensure that the epidemic in that city is patently increasing. the second set of criteria was designed to capture cities where there was a rapid onset of increased influenza-related mortality. they therefore used a higher threshold on mortality in week t i þ , but less strict conditions on rate of growth in the following two weeks. the week of infection determined was found to be relatively robust to the precise choice of thresholds used. for further details on the algorithm and a spatio-temporal display of the result, see the electronic supplementary material. in formulating our inter-city transmission model, we take the city as our unit of study. each of n cities, i, has an infection time t i , an invariant population size p i and a time-varying mortality rate, r i,t at time t. infected city i is separated from susceptible city j by distance d ij . each week, each city can be in one of the three disease states: susceptible, latent or infectious. we assume that all cities are susceptible at the start of a wave, they are latently infected for one week on infection, and that a city becomes infectious the week after it becomes infected. we assume that all transmission is endogenous to england and wales or us after external seeding to the first infected city in each territory. if a city becomes infected in week t i , the candidate infectors are only those cities that are infectious in week t i . we assume that the transmission parameters are constant through time. the model formulation aims to capture the effect of distance and population size on the connectivity of cities. three modes of spatial transmission are considered: density-independent connectivity, densitydependent connectivity and an intermediate form where the degree of density dependence is estimated. the model also examines the different assumptions regarding a city's infectivity over time. the force of infection, l is the hazard of infection from one city to another. from infected city i on susceptible city j at time t, it is: where source city population and distance are normalized together. n and m are estimated parameters on source and destination population sizes, respectively. d ij represents the distance between cities with power parameter g to be estimated. w is an estimated parameter relating the infectivity of a city to its mortality rate. when w ¼ , the infectiousness of a city at time t i is proportional to the death rate in that city at time t i þ . we use one week as a lag from infection to death [ , [ ] [ ] [ ] . a value of w ¼ gives a flat infectiousness profile, independent of the death rate in the source city. intermediate values of w give variation in infectiousness, which scales sub-linearly with weekly mortality. estimating w allows us to assess whether mortality rate is a good proxy for infectiousness in an infected city. b is a time-invariant estimated infectivity term. parameter describes the strength of connection of a susceptible city to all possible infectors. ¼ gives the density-dependent model and ¼ gives the density independent model. by allowing to vary, we allow the model to estimate the degree of density dependence in connectedness between the cities. the total force of infection on city j at time t is given by: where since the force of infection is a hazard, the probability that a susceptible city j is infected in a week t j is given by: t¼ Àl j;t ! ð À expðÀl j;t j ÞÞ: we used a bayesian framework for statistical inference. the log-likelihood is given by: ln p t j À Á : we explore the joint posterior distribution of parameters by markov chain monte carlo (mcmc) sampling [ , ] . we sampled parameters on a logscale using a random walk update scheme. b and g were jointly updated, while , m and n were updated singly. five mcmc chains were started from a variety of start points within a credible range to assess convergence. convergence was achieved within iterations for all models from all starting parameter values. for each model, the chain was run for iterations including a burn in of . parameter estimates and equal-tailed per cent credible intervals were obtained from the posterior distribution of values thinned from the last samples of the mcmc chains. to investigate which components are most important for describing the spread of influenza, we consider a set of simplified variants of the model presented above. in those variants, each parameter can be either fixed at , at or be estimated by mcmc. for a full comparison of each component of the model, see the electronic supplementary material. the deviance information criterion (dic) is used to compare models [ ] . this is calculated using the median parameter values owing to non-normality in the likelihood [ , ] . lower values are preferable and a difference of around units is considered important [ ] . the model is used to generate epidemic trees [ , ] . we sample parameter sets from the joint posterior distribution and calculate the probability of infection for each potential infector city. the most likely tree for each parameter set is generated by calculating which 'infector' city has the highest probability of infecting each 'infectee' city. the distance to this infector, the probability of the infector-infectee pair and the number of infectees each infector creates are calculated for each parameter set. mean values are weighted by the frequency of infector -infectee pairs from trees. we examine the ability of the models to recreate the observed epidemic by simulation. we use parameter sets sampled from the joint posterior distribution and for each set, we simulate an epidemic using the first infected city as a source of infection. once a city is infected, the observed mortality curve is used to model the infectiousness of that city through time. we also calculate the probability distribution of the week of infection for each city conditional upon the observed epidemic up to that time point. we use parameter sets sampled from the joint posterior distribution and for each set, we calculate the probability of infection each week for each city given the epidemic observed up to that time point. we use welch's two-tailed t-test to differentiate outlying groups. comparison of spatial and non-spatial population-independent models shows that inclusion of distance substantially improves model fit for both england and wales and the us (d dic ¼ . and d dic ¼ . , respectively). dic and parameter estimates for the distance-only model are given in column of tables and . previous formulations of the gravity kernel in the literature have considered either density-dependent ( ¼ ) or density-independent transmission ( ¼ ). figure compares the fit (expressed by the posterior deviance) of these two formulations and with that from the model where the degree of density dependence, , is estimated. this comparison is made for models assuming no linear or a fitted power-dependence of spatial coupling on both source and destination city population size. in figure a , w is estimated, whereas in b it is fixed at . see model components in the electronic supplementary material for further comparisons. for england and wales (figure a), in each population context the variant that estimates the degree of density dependence (the lightest curve of each colour) gives a slightly better fit than models with no density dependence, with pure density dependence fitting substantially less well. the comparison also shows that the models which estimate the effect of origin and destination city population sizes on the connectivity of cities are much better than either the populationindependent or linear population size-dependent models. the same set of comparisons is made for the us in figure b . the situation is more complex with the posterior distribution of many model variants lying in the same area. comparisons by dic value cannot distinguish these models. unlike in england and wales, there is no density-dependence variant which has lower deviance for all three of the population sizedependence variants examined. inclusion of nonlinear population size-dependence does not penalize the fit of the us model, and so cannot be definitively excluded as being consistent with the data. the models presented in columns and in table have different population relationships, but the same dic score. the credible intervals on the population parameters of the densitydependent population with infectivity model (column ) are very wide suggesting that little information is added by the inclusion of these parameters. in england and wales, the lowest dic model is one where the degree of density dependence is estimated and the effect of population is also estimated. this is in contrast to the us where population-independent models either with density-dependent or estimated density dependence spatial interaction terms are indistinguishable. we tested models with three types of infectiousness profile through time: constant infectivity, a linear relationship between infectivity and mortality in the week ahead, and an estimated power-law relationship between mortality and infectivity. mixing was poor when estimating w with the us data so we only compare the first two models in that setting. in england and wales, the linear infectivity model has a dic value of more than above either the constant or estimated infectivity model. parameter estimates for the constant-infectivity and estimated-infectivity model variants are shown in columns and of table using the density-dependent population-dependent framework from the previous comparison in england and wales. these two models are indistinguishable by dic (d dic ¼ . ). estimates for all other parameters are very comparable between these two models. the estimated relationship includes two inputs from the infected city: the mortality rate and the population of the city. it can be more difficult to estimate parameters regarding infectivity, so we tested a model which takes only one piece of information from the infected city. the final column in table shows a model which takes the mortality rate from the infected city into account but does not include the population size of that city. there is an improvement in the dic score for this model of . over the constant infectivity model. table shows parameter estimates for models in the us. the difference in dic score between a constant infectivity model and one with a linear relationship between mortality and infectivity is negligible in either a distance-only model framework (columns and ) or a population-dependent framework (columns and ). adding infectivity information does not improve the fit of the model. in the england and wales dataset, the lowest dic model is the single infected city parameter model in column of table . the model is dependent on the destination population size, has estimated dependence of infectivity on mortality and an estimated intermediate degree of density dependence. the distance power g was estimated as . ( . , . ). a lower value was found for models in the us, where for the most parsimonious low dic model (density dependent, population independent), g was estimated as . ( . , . ). figure shows the distance kernels for the two datasets. the credible intervals for g overlap for the two datasets. the power parameter on the destination city population, m, was estimated at . ( . , . ) in england and wales. the credible intervals exclude , demonstrating that as population size increases, the susceptibility of the city increased more slowly. we used the posterior median parameter estimates fitted to the england and wales dataset to calculate a likelihood value in the us dataset. by likelihood ratio test, this value was not different from the most parsimonious low dic us model ( . , . , p . . ). we therefore cannot reject the assumption that spread had the same characteristics in the us and england and wales, though clearly the smaller size of the us dataset reduces inferential power. the epidemic during which each city was infected. inferred city-to-city infection events more frequent than per cent (in trees) are shown in black, events of lower frequency are shown in grey. interactions in weeks - are longer range than those in weeks - ( p , . ), which are in turn longer range than those in weeks - ( p , . ) (figure d ). the probability that the most likely infector was responsible for each infection falls as the epidemic progresses because there are many more potential infectors available later (figure e). cities infected early give rise to more infections than those infected late in the wave, as expected, but the range is large, with some early cities giving rise to no new infections (figure f ). figure shows results for two models using the us data. we compare the most likely infection trees for the distance-only constant infectivity model with parameters inferred from the us data (figure a) with a model where parameters used to generate the trees are taken from the england and wales single-infected city parameter model (figure c). in the distance-only constant infectivity model, the nearest infected city is always the most likely infector. in contrast, with the england and wales parameters, some links between cities are high frequency, while other cities have several potential infectors of intermediate frequency ( figure b) . as in england and wales, infection events inferred early in the epidemic have a higher support than those later in the epidemic. there are some exceptions owing to the distribution of cities in the us dataset-oakland and san francisco are distant from all other cities but very close to each other. in the distance-only constant infectivity model, some cities may give rise to a large number of new infections (e.g. pittsburgh gives rise to nearly a quarter of infections) (figure d ). the effect of a city acting as a hub of infection is reduced in the more complex model, as the risk of infection from one city to another is the combined effect of several factors including distance. for england and wales, there is a relatively good agreement between observed and simulated epidemic curves (figure b). the observed epidemic curve rises more steeply than the simulation curves in the early stages of the epidemic, and peaks one week earlier than the simulation mean. this suggests that the model may underestimate the external infection pressure early in the wave. we calculated the probability that a city was infected in each week given the observed behaviour of all other cities up to that time. in england and wales, of cities lie within the per cent interval of their expected distribution. figure a shows the cities which the observed infection week lies outside the stricter inter quartile interval. for further information see the electronic supplementary material. there are no population size ( p ¼ . ) or density trends ( p ¼ . ) in these cities, which are typically infected later in the epidemic ( p , . for difference in infection week). in the us, all cities lie within the per cent probability interval and all but three lie within the inter quartile interval. those three outlier cities are smaller than other cities ( p ¼ . ) but equally distributed in space ( p ¼ . ) and time ( p ¼ . ). we have tested the effect on parameter estimates in england and wales of relaxing the single-introduction assumption inherent in the model. we re-estimated the parameters conditioning on infections that occurred from week of the epidemic onward. there is a small increase in the kernel power parameter estimate, which causes the kernel to decay more rapidly with distance (electronic supplementary material, figure s ). this suggests that the very long-range interactions, which are forced to occur early in the epidemic impact the shape of the kernel. however, the credible intervals largely overlap which indicates this assumption does not affect the fit of the model to a large degree. in the us the simulated curves for the distance-only constant infectivity model are shown in figure e and for the england and wales parameters in figure f. in both cases, the mean simulated and observed curve are very comparable, with the distance-only constant infectivity model giving peak incidence in the same week as observed. figure g shows the observed week of infection against the simulated week of infection for all simulated epidemics. there is good correlation between the observed and simulated weeks of infection for both parametrizations. we have tested the effect of thinning the england and wales dataset so that it more closely resembles the us dataset to determine if the differences in formulation between the best models for each dataset are owing to the smaller number of cities in the us dataset. we removed all cities with fewer than inhabitants in england and wales leaving cities distributed quite evenly in england and wales as shown in the electronic supplementary material, figure s . there were identifiability problems in estimating the density-dependence parameter using the thinned dataset. the best model by dic comparison gave a distance-only interaction (no dependence on population size) with infectivity scaling linearly with mortality in a density-independent framework. as we found with the us data, it is difficult to disentangle the effects of population and infectivity parameters because these feature in different combinations in comparable dic models. we have presented a statistical analysis of the spatiotemporal spread of the influenza pandemic between cities in england and wales and the us. the results demonstrate that for england and wales, a model with intermediate levels of density dependence in the connectivity between cities gives the best fit to the observed pattern. for the us dataset, where there are few, large and widely spaced population centres, estimating the degree of density dependence does not improve the fit. in both contexts, city population size affects inter-city coupling sub-linearly. parameter estimates and model formulation inferred from the data of england and wales explain the us dataset well. gravity model parameter estimates generated in this study are comparable with values found in studies describing the spread of seasonal influenza [ , ] . our analysis demonstrates the degree of spatial locality in the large-scale geographical spread of influenza in both england and wales and the us in . however, it is difficult to directly compare the kernel power estimate from this study with those from other studies owing to differences in the functional forms used. for instance, viboud et al. [ ] estimate two power parameters above and below a given distance threshold when modelling the spread of seasonal influenza in the us. gravity models used to describe the spread of measles in the uk by xia et al. [ ] assumed a kernel power of , rather than fitting this parameter. the distance power estimates we found for england and wales and the us are quite different from each other. it is not surprising that there is a disparity in the distance kernel in england and wales and the us, as the spatial scale in the us is much larger than in england and wales. in comparing the us and uk, it should be noted that the mean distance between cities is of course much larger in the us (see electronic supplementary material, table s ). in theory, this gives better resolution for estimating the kernel shape, as the range of inter-city separations is an order of magnitude larger than for the uk. however, this is counterbalanced by the smaller size of the us dataset, which reduces inferential power. the low kernel power parameter estimates we have found in both england and wales and the us suggests that long-distance interactions were important in spreading influenza between distant cities in both countries. at the start of the major autumn wave in , the armistice was more than two months away and it is likely that travel relating to the war effort, including troop movements, might have enhanced the frequency of long-distance movements. density-dependent gravity models are frequently used to explain the connectivity of urban centres for human diseases [ , ] . there is good evidence from the estimates of in this analysis for england and wales that the density-dependent model underestimates the total force of infection on remote cities. the per cent credible interval for includes , which indicates that the density-independent model formulation cannot be definitively excluded as an explanation for the data. there was limited statistical power to estimate the degree of density dependence in the us context, but use of the england and wales best-fit model to describe the us data gave a very similar dic to the best-fit us model. hence, it is not clear if the difference in the estimated density dependence found between the us and the england and wales is because of the large differences in the degree of population coverage between the us and england and wales datasets. our results using a subset of the england and wales dataset suggest that the degree of density dependence is a difficult parameter to estimate when coverage is low. the low power on destination city size found in fitting the gravity model to the england and wales dataset shows that connectivity of a city increases sub-linearly with population increase. when modelling spread of influenza in the us, viboud et al. [ ] found very comparable low values of the population exponents with the infectious city lower than the susceptible. differing results come from the analysis of measles data in great britain with a power coefficient on infectious populations estimated at approximately . [ ] . we found the best-fit model in england and wales does not include the population size of the infector (origin) city, a result which needs further examination in future work. differences in our population parameter estimates and those from studies on contemporary populations are likely to differ owing to changes in human mobility patterns since . our estimate for england and wales that the infectivity of a city is sub-linearly related to mortality, suggests that the rate of death in a city is not as important to infectivity as the presence or absence of disease. other studies have used constant infectivity terms for the analysis of human seasonal influenza [ ] . however, our estimates do support some level of mortality dependence, suggesting that cities with a very high influenza burden, usually later in the epidemic wave, are more infectious than newly infected cities. in the us dataset, the best-fit model gave constant infectiousness, but again this may be due to a lack of power to estimate such parameters from the us dataset. it may also be caused by non-uniform infection pressure from cities not in the dataset, which could mask an infectivity relationship for the cities that are given. future possible extensions of this work include relaxing the assumption that all cities were equally susceptible at the start of the autumn wave of the pandemic. the variation in the onset of infection in cities may, in part, be due to the differing susceptibility of each city owing to differing attack rates experienced in the spring -summer wave, or population-level immunity from the pandemic or seasonal strains. however, the low case fatality of the first wave and age-specificity of infection between waves need to be understood before spatial heterogeneity in susceptibility can be discerned. there are varying reports on the magnitude and mechanism of the effect of infection during the first wave on attack rates in subsequent waves [ ] [ ] [ ] [ ] [ ] [ ] . further analysis of the datasets considered here may provide an opportunity to disentangle these effects. transmission dynamics of the etiological agent of sars in hong kong: impact of public health interventions strategies for containing an emerging influenza pandemic in southeast asia strategies for mitigating an influenza pandemic mitigation strategies for pandemic influenza in the united states synchrony, waves, and spatial hierarchies in the spread of influenza the role of the airline transportation network in the prediction and predictability of global epidemics simulating the effect of quarantine on the spread of the - 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influenza pandemic time from illness onset to death, influenza and pneumococcal pneumonia monte carlo sampling methods using markov chains and their applications markov chain monte carlo in practice bayesian measures of model complexity and fit deviance information criteria for missing data models version . user manual the construction and analysis of epidemic trees with reference to the uk foot-and-mouth outbreak different epidemic curves for severe acute respiratory syndrome reveal similar impacts of control measures mitigation measures for pandemic influenza in italy: an individual based model considering different scenarios ecological and immunological determinants of influenza evolution a biological model for influenza transmission: pandemic planning implications of asymptomatic infection and immunity the influenza pandemic: insights for the st century spatial dynamics of the pandemic r. m. eggo et we thank the mrc for studentship and center support, and the eu fp flumodcont project, the bill and melinda gates foundation, research councils uk and the nih midas initiative for research funding. we also thank pete dodd, judith legrand and james truscott for useful discussions. key: cord- -z vwovw authors: saier, milton h. title: are megacities sustainable? date: - - journal: water air soil pollut doi: . /s - - - sha: doc_id: cord_uid: z vwovw nan increasing numbers of people are moving to cities, causing urban populations to expand. in , only % of the world_s people lived in cities, but by , the percentage had increased to %. soon, over % of the world_s people will live in cities. several questions arise related to this movement: ( ) how rapidly are people moving to cities? ( ) what are the benefits to having a larger urban population? ( ) what are the detriments of such a move? ( ) are city folks taking major risks compared with people living in rural areas? ( ) if so, what are these risks, and how can they be avoided? recently, b.r. gurjar published an article entitled "mega cities: city-states of the future (gurjar, ) ." in this article, he points out that cities contribute enormously to a nation's economy provided that they can manufacture or otherwise generate products that are of global value. in fact, some cities specialize in just one or a few commercial products, say, automobiles, computers, or drugs, so that the people of that city depend on a relatively small number of industrial enterprises for jobs. moreover, the primary product produced by a particular urban population may result from the presence of a single company, and its presence in that city reflects the decisions of just a few executives. decisions to hire, fire, maintain or close a facility can therefore be made on short notice even though they affect the lives of thousands. gurjar defines a megacity as one that has a population of over , , . while there were only two megacities in , new york and tokyo, with populations of . and . million, respectively, we now have such urban centers worldwide with populations sometimes exceeding , , . this tremendous rise results both from astronomical global birth over death rates and from the migration of rural populations to the cities. let_s examine these two primary causes in more detail. every day, there are over , more people on earth than the day before; , is the minimal number of births over deaths worldwide in a single day! moreover, about % of the world_s rural population moves from the country to the cities every two years. this amounts to an average increase in the urban population of roughly million people per year, due solely to migration. urban fertility rates, generally lower than rural fertility rates, but nevertheless appreciable, particularly in third world countries, plus the tremendous influx of people from the country, accounts for the rise in the urban population. in contrast to country life, cities depend on extensive infrastructural support systems. these pro-vide food, water, energy, transportation, lodging, information transfer, recreation and other necessities. the sudden loss of a city_s infrastructure due to a natural or man-created disaster would be expected to promote human suffering of a magnitude that far surpasses anything that could have occurred in the past with a less centralized population living in a rural setting. this fact emphasizes one of the primary risk factors associated with urban life. past examples of urban disasters abound: the great san francisco earthquake and fire of caused thousands of deaths and tremendous loss of property. in fact, most of the city was destroyed, and two-thirds of the population, some , people, suddenly found themselves homeless. the same disaster today, occurring in any one of our megacities, could cause -to -fold more damage, homelessness and loss of life. in this regard, it is important to note that in addition to san francisco, los angeles and delhi, which fall within major quake zones, have made no provision for the millions of people who would lose their homes if such a quake were to occur. the two hurricanes that hit the gulf coast last year devastated new orleans and biloxi, and would have done the same in galveston and houston if the winds hadn_t shifted at the last moment. global warming is believed to have greatly increased the intensity and duration of these hurricanes. such storms are likely to become increasingly destructive with time. the devastation observed for new orleans will become a recurrent theme as the oceans increase in temperature and sea levels rise. all coastal megacities are potential targets, and most megacities are coastal. extremes of weather conditions can bring sudden, unexpectedly heavy precipitation. heavy rainfall and consequent mudslides and wall collapse in mumbai, india brought the city to a virtual standstill in one day, on july , . thirty-seven inches of rain fell on the city within a -h period, more than had ever been observed for an indian city in all of recorded time. thousands were killed. was this another consequence of global warming, or was it merely a chance event? if the former, then such extreme occurrences can be anticipated to be more frequent in the future. in fact, this is exactly what the experts on climate change have been predicting. the heat wave in europe led to tens of thousands of human deaths as well as extensive wild fires, particularly in spain and portugal. the in-creased incidences of forest fires in the western united states over the past few years, especially during the heat wave of , resulted in loss of natural resources as never observed previously in recorded history. global warming again played a major role. with a global economy, such events almost anywhere in the world can have adverse effects on the security of urban life. consequences of war are often devastating. one atomic bomb can ruin the whole day for millions of people living in close proximity in a megacity. the same bomb dropped in the country would have longterm environmental consequences, but would not cause comparable loss of human life and property. moreover, militant countries usually target cities, rarely the country. war is just one of many potential man-promoted forms of devastation that affect urban populations far more than rural populations. with the growth of urban populations, dependencies on modern technologies increase. estimates indicate that for the urban u.s. population, a majority of food products travel over a thousand miles before reaching the consumer. we depend on a truly global economy where coffee comes from south america, pineapples are from hawaii, apples are from the state of washington, and citrus comes from california or florida. interference with crop production, transportation or storage can cause major hardships to urban populations. such hardships are not felt by rural populations that produce their own food locally. moreover, using our current means of transportation, the further a product is transported, the more fossil fuels must be burned, contributing to global warming. a global economy means sensitivity to natural and man-promoted disasters. regardless of whether a war, a hurricane or economic manipulation is responsible, millions of people can lose their sense of security and their lives. disasters of this magnitude were unheard of in the past. food and water availability are interlinked. affluent populations tend to eat more meat, much to the detriment of their own health and the environment. raising meat in the u.s. is responsible for one-quarter of the land use and nearly one-half of the water consumption. the statistics are similar in many other countries. the harmful impact on the environment of eating meat is estimated to be times that of eating plant products. while some have claimed that urbanization should allow for reforestation and restoration of natural habitats, the sobering facts suggest that positive effects will be minimal compared to the negative ones. it is well established that disease transmission is greatly enhanced when the population density increases, particularly when and where squalid conditions exist. in many megacities worldwide, the unavailability of sterile water and/or adequate sewer systems promotes the likelihood of epidemics. this probability is enhanced by the continual appearance of new human diseases such as aids, sars, and avian flu as well as by the reoccurrence of old diseases such as tuberculosis, cholera and plague, due to the evolution of drug resistant fungi, protozoans, bacteria and viruses. moreover, global warming, with ambient temperatures approaching body temperatures, will facilitate disease transmission, particularly those mediated by insects and microbes. combine these problematic situations with unanticipated natural or man-made disasters that can compromise infrastructural stability, and the consequences to an urban population can be devastating. increased local pollution is still another consequence of urbanization. today, children raised in los angeles have % less lung capacity than kids raised in a rural environment. local air pollution is the cause. statistical analyses have also shown that urban populations suffer from substantially higher cancer and disease frequencies than rural populations. although causal relationships have been less easy to establish, all racial types suffer from increased rates of these diseases when living in cities. the causes are not difficult to imagine. as the numbers of megacities in the world increase, environmental and health risks increase proportionally causing a rise in mortality rates. only a single humane solution is likely to provide longterm relief from this precarious situation: reduction in the human population. while conversion to more sustainable lifestyles and minimizing pollution will help, these advances can only be considered to be short-term solutions. as long as human populations continue to increase and become concentrated in urban centers, both immediate health problems and long-term environmental consequences will persist. moreover, the unfortunate consequences of unexpected but increasingly probable disasters can be expected to be proportional to population size. for achievement of human health, safety and a sustainable metropolis, the solution requires diminution of the human global population. numerous studies conducted worldwide have shown that this goal is attainable through the free provision of birth control and abortion services worldwide. such a prospect is eminently achievable in today_s societies, provided that wealthy countries are willing to make the financial means available to third world countries. this is estimated to cost a mere $ billion per year, a small fraction of what the u.s. now spends for war and destruction in iraq with no benefit to anyone. when birth control and abortion are provided, and women make the decisions, fewer babies are born, regardless of the social, economic and educational levels of the women involved. although the need to promote this all-important goal is now recognized by all of the experts, implementation of such a program has, in the past, been thwarted by irrational thought. educated citizens of all developed countries have the responsibility to come out of the closet, become vocal, and confront the mighty irrational elements of society. only socially responsible politicians can be tolerated. a major effort must therefore aim to overcome irrationality through logic, deductive reasoning and education so as to promote the best possible course of action. selfish, short-term interests must be recognized for what they are. maximal benefit for all world citizens must be sought. mega cities: city-states of the future. the financial express key: cord- -v queyh authors: storch, david-maximilian; timme, marc; schroder, malte title: incentive-driven discontinuous transition to high ride-sharing adoption date: - - journal: nan doi: nan sha: doc_id: cord_uid: v queyh ride-sharing - the combination of multiple trips into one - may substantially contribute towards sustainable urban mobility. it is most efficient at high demand locations with many similar trip requests. however, here we reveal that people's willingness to share rides does not follow this trend. modeling the fundamental incentives underlying individual ride-sharing decisions, we find two opposing adoption regimes, one with constant and one with decreasing adoption as demand increases. in the high demand limit, the transition between these regimes becomes discontinuous, switching abruptly from low to high ride-sharing adoption. analyzing over million ride requests in new york city and chicago illustrates that both regimes coexist across the cities, consistent with our model predictions. these results suggest that current incentives for ride-sharing may be near the boundary to the high-sharing regime such that even a moderate increase in the financial incentives may significantly increase ride-sharing adoption. sustainable mobility [ ] [ ] [ ] [ ] [ ] [ ] is essential for ensuring socially, economically and environmentally viable urban life [ , ] . ride-sharing constitutes a promising alternative to individual motorized transport currently dominating urban mobility [ ] . recent analyses suggest that large-scale ride-sharing is specifically suited for densely populated urban areas [ ] [ ] [ ] [ ] [ ] . by combining two or more individual trips into a shared ride served by a single vehicle, ride-sharing increases the average utilization per vehicle, reduces the total number of vehicles required [ ] and thereby mitigates congestion and environmental impacts of urban mobility [ ] . hence, embedding ride-sharing for trips that would otherwise be conducted in a single-occupancy motorized vehicle, is preferable from a systemic perspective. previous research focused on algorithms to implement large-scale ride-sharing [ ] as well as the potential efficiency gains derived from aggregating rides [ , , ] . generally, matching individual rides into shared ones without large detours becomes easier with more users, increasing both the economic and environmental efficiency as well as the service quality of the ride-sharing service [ , , ]. yet, if and under which conditions people are actually willing to adopt ride-sharing remains elusive [ ] [ ] [ ] [ ] [ ] [ ] . in particular, it is unclear how to encourage an ever growing number of ride-hailing users to choose shared rides over their current individual mobility options [ ] [ ] [ ] . in this article, we disentangle the complex incentive structure that governs ride-hailing users' decisions to share their rides -or not. in a game theoretic model of a one-to-many demand constellation we illustrate how the interactions between individual ride-hailing users give rise to two qualitatively different regimes of ride-sharing adoption: one low-sharing regime where the adoption decreases with increasing demand and one high-sharing regime where the population shares their rides independent of demand. analyzing ride-sharing decisions from approximately million ride-requests in new york city and an additional million in chicago suggests that both adoption regimes coexist in these cities, consistent with our theoretical predictions. our findings indicate that current financial incentives are nearly, but not fully, sufficient to stimulate a transition towards the high-sharing regime. . contrasting ride-sharing adoption despite high request rate in new york city. fraction of shared ride requests from different origins (red) served by the four major for-hire vehicle transportation service providers in new york city by destination zone (january -december ) [ ] . gray areas were excluded from the analysis due to insufficient data (see methods). the fraction of shared ride requests differs significantly by origin and destination, even though the average overall request rate is similar for all four origin locations. a,b some areas, such as east village and crown heights north, show a high adoption of ride-sharing services. c,d despite a similarly high request rate, other locations, such as jfk and laguardia airports, show a significantly lower adoption of ride-sharing services with a complex spatial pattern across destinations. ride-sharing adoption (see supplementary information for details). these findings hint at a complex interplay of urban environment, demand structure and socio-economic factors that govern the adoption of ride-sharing. to disentangle these complex interactions, we introduce and analyze a game theoretic model capturing essential features of ridesharing incentives, disincentives as well as topological demand structure. trade-offs between incentives determine the decision to share a ride, or not. a shared rides offer advantages and disadvantages compared to single rides. on the one hand, they offer financial discounts typically proportional to the distance of a direct single ride (blue, dotted). on the other hand, rides shared with strangers may be inconvenient due to other passengers in the car (e.g. loss of privacy or less space, green) and may include detours compared to a direct trip to pickup or deliver these other passengers (orange, solid compared to dotted). b the decision to book a shared ride depends on the balance of all three factors. if the expected utility difference e[∆u] = e[u share ] − e[u single ] between a shared and a single ride is positive, the financial discounts overcompensate detour and inconvenience effects; users share. if e[∆u] is negative (as illustrated), users prefer to book single rides. the decision of ride-hailing users to request a single or a shared ride reflects the balance of three fundamental incentives ( fig. ) [ , ] : discounts. ride-sharing is incentivized by financial discounts granted on the single ride trip fare, partially passing on savings of the service cost to the user. often, these discounts are offered as percentage discounts on the total fare such that the financial incentives u share fin > are proportional to the distance or duration d single of the requested ride, u share fin = d single , where denotes the per-distance financial incentives. in many cases, these discounts are also granted if the user cannot actually be matched with another customer into a shared ride [ , ] . detours. potential detours d det to pickup or to deliver other users on the same shared ride discourage sharing. the magnitude of this disincentive u share det < increases with the detour d det . inconvenience. sharing a ride with another user may be inconvenient due to spending time in a crowded vehicle or due to loss of privacy [ , , ] . this disincentive u share inc < scales with the distance or duration d inc users ride together. in the following we take u share det ∼ d det and u share inc ∼ d inc , describing the first order approximation of these disincentives and matching the linear scaling of the financial incentives with the relevant distance or time. these incentives for a shared ride describe the difference ∆u in utility compared to a single ride or another mode of transport. the overall utility of a shared ride is then given by where the utility u single for a single ride describes the benefit of being transported, as well as the cost and time spent on the ride. the factors , ξ and ζ denote the user's preferences. by rescaling the utilities (measuring in monetary units), directly denotes the relative price difference between single and shared rides whereas ζ and ξ quantify the importance of inconvenience and detours relative to the financial incentives (see supplementary information for details). for a given origin-destination pair with fixed single ride distance d single , financial incentives are constant for a given discount factor . in contrast, detour and inconvenience contributions depend on the destinations and sharing decisions of other users. their magnitude depends on where these users are going and on the route the vehicle is taking for a shared ride (see methods). the decision to share a ride is determined by the expected utility difference (see fig. ) where e[·] signifies the expectation value over realizations of other users' destinations and sharing decisions conditional on one's own sharing decision. to understand how these incentives determine the adoption of ride-sharing, we study sharing decisions in a stylized city network [ ] with a common origin o (e.g., from a central downtown location) in the center and multiple destinations d (illustrated in fig. ). two rings define urban peripheries equidistant from the city center. branches represent cardinal directions of destinations. requests for shared rides will only be matched along adjacent branches, if the shared ride reduces the total distance driven to deliver the users and to return to the origin compared to single rides (see methods). pairing at most two users who request a shared ride, the problem of matching shared ride requests reduces to a minimum-weight-matching with an efficient solution, eliminating the influence of heuristic matching algorithms [ , ] (see methods for details). in this one-to-many setting, users requesting a shared ride would only share a ride if they make their requests within some small time window τ . therefore, we consider a game with s = s τ users travelling to a uniformly chosen destination location, where s denotes the average request rate. these users have the option to book a single ride or a shared ride at discounted trip fare. their decision to share depends on their expected utility difference e[∆u(d)] [eq. ( )], now depending on their respective destination d. from the utility differences e[∆u(d)], we compute the equilibrium sharing probabilities π * (d) with which users from destination d adopt ride-sharing to maximize their expected utility (see methods for details). at fixed discount and preferences ζ and ξ ride-hailing users may decrease their overall adoption of ride-sharing π * as the total number s of users increases (see fig. a , blue), even though ride-sharing becomes more efficient with higher user numbers. here · denotes the average over all destinations d. while for small request rates everybody is requesting shared rides (fig. b) , a distinctive sharing/non-sharing pattern emerges along the branches of the city network upon higher demand (fig. c,d) , before the adoption of ride-sharing eventually fades out for high request rates, s (fig. e) . this observation offers a novel perspective on the prevalent conclusion that increased demand improves the shareability of rides [ , ] . while more rides are potentially shareable, less people may be willing to share them. the underlying incentives explain this phenomenon: ideally, a user wants to book a shared ride (financial incentive) but without actually sharing the ride (inconvenience and detour). the expected detour and inconvenience mediate an interaction between ride-hailing users, turning ride-sharing decisions into a complex anti-coordination game. for small request rates, i.e. small numbers of concurrent users s, the probability p match (d) for a user with destination d to be matched with other users is low (see fig. a , gray). consequently, the expected detour is also small (analogously for the inconvenience). as illustrated in fig. b , bottom, financial incentives outweigh the expected disadvantages of ride-sharing such that everybody is requesting shared rides, π * (d) = for all destinations d, but is only rarely matched with another user. as the number of users s increases, the provider can pair ride requests more efficiently given constant sharing decisions, ∂p match (d)/∂s > , resulting in more requests that are actually matched with another user (see fig. a ). consequently, the expected detour and inconvenience also increase. however, instead of reducing the average adoption of ride-sharing homogeneously across all destinations, neighboring destinations adopt opposing sharing strategies (see fig. b ). in this sharing pattern, only destinations in identical cardinal direction can and will be matched into a shared ride, minimizing the detours for shared requests and simultaneously disincentivizing other users to start sharing due to high expected detours ( fig. c-e bottom) . as the number of users s increases further, the probability p match (d) would also increase at given sharing adoption π(d). this leads to an adoption of mixed sharing strategies where the financial discounts in this configuration, users requesting a shared ride never suffer any detour while users that do not share are disincentivized from doing so due to their high expected detour (compare bottom part of panel c). for high numbers of users (s = and , panels d and e), the probability to be matched with another user when requesting a shared ride increases and the financial incentives cannot fully compensate the expected inconvenience. the adoption of ride-sharing decreases until the financial incentives exactly balance the expected inconvenience (panels d and e, bottom). illustrated here for financial discount = . and inconvenience and detour preferences ζ = . and ξ = . . and the expected inconvenience are exactly in balance ( fig. d and e) . further numerical simulations demonstrate that this transition robustly exists also for heterogeneous demand distribution across the destinations and different origin locations within the network (see supplementary information) . naturally, if the discount is sufficiently large such that the financial incentives completely compensate the expected inconvenience, > ζ, all users share also in the high request rate limit, s → ∞. in this limit, d single = d inc as detours disappear, e[d det ] → , due to an abundance of similar requests. figure a -b summarizes these results in a phase diagram for the ride-sharing decisions as a function of financial discount and number of users s, illustrating under which conditions the users adopt ride-sharing (high-sharing regime) and under which conditions the users only share partially or not at all (low-sharing regime). for fixed values of financial discounts , different behavior emerges for different inconvenience preferences ζ. if ζ is sufficiently small (fig. a) , the system is in the high-sharing phase and the number of users requesting a shared ride is s share = s. otherwise, the system switches from the high-to the low-sharing state (fig. b, compare fig ) . figure c illustrates the scaling of s share in both states as s increases. in the partial sharing state, s share becomes constant for large s, such that s share /s → as s → ∞ (compare fig. a) , implying a discontinuous phase transition between low-sharing and high-sharing regimes for large s when the financial incentives exactly balance the inconvenience, c /ζ c = (see supplementary information for details). two qualitatively different regimes of ride-sharing adoption. a,b phase diagram of fraction of shared rides s share /s for different inconvenience preferences ζ. ride-sharing is adopted dominantly if the financial discount fully compensates the expected inconvenience (high-sharing, dark blue). otherwise, the total number of shared ride requests saturates and the overall adoption of ride-sharing decreases with increasing number of users s (low-sharing, compare fig. a ). in the limit of an infinite number of requests s → ∞ the transition becomes discontinuous (see supplementary information) . c with identical financial discounts = . , different sharing behavior emerges for different inconvenience preferences ζ. when ζ < all users request shared rides (s share = s, dark blue triangles, red line in panel a). when ζ > the system is in a low-sharing regime where users request shared rides at low numbers of users s but the number of shared ride requests saturates and becomes constant at high s (s share < s, light green triangles, red line in panel b). in the low-sharing regime, spatially heterogeneous patterns of ride-sharing adoption emerge (compare fig. b -e). in a real city with heterogeneous preferences across different locations and constant financial discounts , the sharing decisions may, on an aggregate level, appear to be in a hybrid state between the high-and low-sharing phases predicted by our model. indeed, the ride-sharing adoption across different origin locations in new york city and chicago, illustrated in fig. , matches the qualitative sharing behaviors at different preferences in our model (compare fig. c ). at locations with a low request rate s, the fraction of shared ride requests increases linearly with more requests, s share ∼ s. at high request rates, sharing decisions differ by origin zone (compare fig. ): for crown heights north and east village the linear scaling prevails, indicating is sufficiently large to compensate the expected inconvenience and detour effects completely. in fact, the spatial pattern of fraction of rides shared appears to be largely homogeneous across destinations as expected in this state (fig. a) . other origins with a similarly high request rate, such as jfk and laguardia airports, accumulate on a horizontal line with a constant number of shared ride requests per time. for these zones s share has saturated for the given financial incentives and will not increase with higher request rate. the sharing decisions in these locations are spatially heterogeneous across the city (fig. c) , consistent with the low-sharing state observed in our model (compare fig. ). together with fig. a and b, these observations suggest that financial incentives in new york city are at the phase boundary between the high-and low-sharing regime and slightly higher discounts may significantly increase sharing in some areas. ride-sharing adoption in new york city and chicago is consistent with the predicted high-and lowsharing regimes. a,b sharing decisions for new york city and chicago (blue dots) accumulate on two branches corresponding to the predicted high-and low-sharing regime as a function of request rate (compare fig. ) . at low request rates, the number of requests for shared rides increases linearly with the total number of requests (compare red diagonal). at high request rates, the sharing decisions differ between locations (compare fig. and , see also supplementary information). as inconvenience preferences ζ are naturally heterogeneous in the cities, adoption is in a hybrid low/high-sharing state. c,d for origins in the high-sharing state a spatially homogeneous pattern of ride-sharing adoption emerges across destinations. e,f for origins in the low-sharing state a spatially heterogeneous pattern forms. the agglomeration of most data points on the high-sharing branch for new york city suggests that the financial discounts are close to the boundary of the high-sharing phase. however, the slope of the high-sharing branch indicates that only about % of ride-hailing users consider ride-sharing as an option. while about % of requests are shared in the high-sharing regime in chicago, this potential is largely not realized. most data points at locations with high request rates accumulate on the horizontal line representing the low-sharing regime. seven large and busy zones in chicago with up to requests per minute (not shown) fall in between the high-and low-sharing state (see supplementary information for details). an analysis for the ride-sharing adoption across more than million trips in chicago (see methods and supplemental material for details) shows similar results (fig. d) , highlighting the existence of the low-sharing regime (horizontal branch s share = const.). even in the high-sharing regime, s share ∼ s, the ride-sharing adoption in new york city and chicago (corresponding to the slope of the diagonal branch in fig. a,b) is below %. in terms of our ride-sharing game, the remaining fraction of requests for single rides corresponds to a user group that does not consider ride-sharing as a potential option at all and, hence, is not captured by our model. the adoption of ride-sharing is governed by the complex interplay between demand patterns, matching algorithms, available transportation services, urban environments and the relevant incentive structure. incentives may include financial savings potentials, detour or delay preferences, various types of inconveniences, as well as sustainability, security and uncertainty [ , [ ] [ ] [ ] . we have introduced a model capturing essential incentives for and against ride-sharing, predicting two qualitatively different regimes of ride-sharing adoption consistent with an analysis of million ride-sharing decisions from new york city and chicago. a basic model includes three core incentive types: financial benefits, potential detours (and thus effectively slower service) and other inconveniences such as reduced privacy resulting from sharing a vehicle. this setting may already reflect many additional factors influencing ride-sharing adoption on an aggregate level. for example, sustainability or uncertainty preferences to first approximation scale with the additional distance driven and may thus be incorporated into the detour preferences. similarly, alternative public transport options may be captured by modifying the effective financial discount and relative inconvenience preferences for individual destinations. as such, we expect the qualitative dynamics to be robust even in more detailed settings taking into account additional conditions (compare supplementary information for different demand distributions). specific, district-level policy recommendations naturally require a more detailed description of the traffic conditions and alternative transport options, capturing all the above-mentioned dependencies. in particular, we predict the existence of two distinct regimes of ride-sharing adoption. for sufficiently strong financial incentives, the number of shared ride requests increases linearly with increasing demand. however, if the financial incentives are weak compared to inconvenience disincentives, the number of requests for shared rides saturates with increasing demand (regime of low ride-sharing adoption). this observation is independent of the choice of origin locations or the specific demand distribution (see supplementary information) and stands in stark contrast to the increasing shareability of rides with high demand [ , , ] . in the limit of large demand, the transition between the two regimes becomes discontinuous, switching abruptly from the low adoption to the high adoption regime with a small change of the incentives. ride-sharing adoption observed across new york city and chicago is consistent with these predictions and demonstrates that both regimes exist across the cities. the data suggest that even a moderate increase of financial incentives may strongly improve ride-sharing adoption in some areas currently in the low-sharing regime. still, the overall low fraction of shared ride requests, even in the high-sharing regime, suggests that an additional societal change towards acceptance of shared mobility is required [ ] to make the full theoretical potential of ride-sharing accessible [ , ] . a carefully designed incentive structure for ride-sharing users adapted to local user preferences is essential to drive this change and to avoid curbing user adoption or stimulating unintended collective states [ , ] . this is particularly relevant in the light of increasing demand as urbanization progresses [ ] . overall, the approach introduced above can serve as a framework to work towards sustainable urban mobility by regulating and adapting incentives to promote ride-sharing in place of motorized individual transport. new york city ride-sharing data. we analyzed trip data of more than million transportation service requests delivered through high-volume for-hire vehicle (hvfhv) service providers in new york city in . the data is provided by new york city's taxi & limousine commission (tlc) [ ] and consists of origin and destination zone per request, pickup and dropoff times, as well as a shared request tag, denoting a request for a single or shared ride. we compute the average request rate across all data throughout taking hours of demand per day as an approximate average. for fixed origin-destination pairs we determine the sharing fraction as the ratio of the total number of shared ride requests and the total number of requests. departure and destination zones represent the geospatial taxi zones defined by tlc [ ] . however, we exclude zones without geographic decoding, nor name tag defined by tlc. for each individual analysis, we fix the destination zone and compute the fraction of shared rides to destination zones. for a given departure zone, if the total number of requests is less than trips in the considered time interval and destination zone, we exclude that destination zone from the analysis to avoid excessive stochastic fluctuations (see supplementary information for details) . chicago ride-sharing data. we additionally analyzed more than million trips delivered by three service providers in chicago in . the data is provided through the city of chicago's open data portal and contains, amongst others, information of trip origin, destination, pickup and dropoff times as well as information whether a shared ride has been authorized [ ] . we restrict ourselves to geospatial decoding of the city's community areas, as well as trips leaving or entering the official city borders. in analogy to new york city, we compute the average request rate across all data for taking hours of demand per day as an approximate average reference time and repeat the analysis explained for new york city. city topology. for our ride-sharing model we construct a stylized city topology that combines star and ring topology [ ] . starting from a central origin node, rides can be requested to destinations distributed equally across two rings of radius (inner ring) and (outer ring), as depicted in figure . the distances between neighboring nodes on the same branch are set to unity. correspondingly, the distances between neighboring nodes are π/ on the inner, and π/ on the outer ring. ride-sharing adoption. we compute the equilibrium state of ride-sharing adoption by evolving the adoption probabilities π(d, t) following discrete-time replicator dynamics [ , ] π(d, t + ) = r(d, t) π(d, t), where the reproduction rate r(d, t) at destination d and time t is and e[x] represents the expectation value of random variable x. we prepare the system in an initial state π(d, ) = . of ride-sharing adoption for all destinations d and set a constant utility of a single ride u single (d) = to ensure positivity of eqn. ( ) . to evolve eqn. ( ), we numerically compute e[u share (d, t)] = e[u(d, t)|share] at each replicator time step t: we generate n = samples of ride requests of size s of which at least one goes to destination d and requests a shared ride. the other s − requests are drawn from a uniform destination distribution. each of them realizes a sharing decision in line with the current probability distribution π(d , t) at their respective destination d at time t. shared ride requests are matched pairwise (see below). from these n = game realizations, we compute the conditional expected utility of sharing. we repeat this procedure for all destinations d and then update all probabilities π(d, t) according to eqn. ( ) . before performing measurements on the system's equilibrium observables, we discard a transient of replicator time steps, corresponding to game realizations per destination. we then measure the average adoption for replicator time steps, representing a proxy for the stationary solution π * (d) of eqn. ( ) and plotted as the sharing fraction in figs. and (see supplementary information for details) . matching. each request set of size s decomposes into single and shared ride requests. we realize the optimal pairwise matching of requests as follows: for shared requests we construct a graph whose nodes correspond to requests and edges encode the distance savings potential of matching the two requests. to determine the distance savings potential we assume that, independent of single or shared ride, the provider has to return to the origin of the trip. after constructing the shared request graph we employ the 'blossom v' implementation of edmond's blossom algorithm to determine the maximum weight matching of highest distance savings potential [ ] . the matching determines the routing and the realization of inconvenience and detour (see supplementary information for more details). in the main manuscript of this article we disentangle the incentive structure of urban ride-sharing and demonstrate how it leads to emergence of two qualitatively different regimes of sharing adoption. a game theoretic model reproduces key features of the ride-sharing activity in new york city and chicago, including spatially heterogeneous patterns of ride-sharing adoption, saturation in the number of shared rides upon increasing demand and provides insights on the underlying mechanisms. this supplementary information provides additional details on the model, methods and results presented, and is structured as follows: in , four high-volume for-hire vehicle (hvfhv) companies (uber, lyft, via, juno) served more than million transportation service requests in new york city, corresponding to approximately trips per day conducted by a population of . million people [ , ] . in this supplementary note, we unveil the spatiotemporal demand patterns underlying this macroscopic number of transportation requests. the flux matrix w (∆t) formalizes the spatiotemporal demand for transportation services between different locations of an urban environment. its entries w o,d denote the number of transportation requests originating at location o and going to location d within a specific time window ∆t. w (∆t) decomposes into where w single (∆t) and w shared (∆t) are the flux matrices describing trip requests tagged as single or shared rides, respectively. we define the fraction of rides shared as the relative ratio of shared rides to absolute number of rides. note that eqn. ( ) is only defined if the total flux between origin and destination exceeds a threshold w min to reduce bias from fluctuations in statistical analyses of p o,d (∆t). we determine w single , w shared and p for the taxi zones in new york city from the new york city taxi fig. b ) and evening ( pm - am) encompassing leisure activity hours ( supplementary fig. c ). independent of daytime, all four origins exhibit complex spatial patterns of ride-sharing adoption across destinations. for jfk and laguardia airport these patterns are robust for all time windows, indicating stable fraction of rides shared to all destinations throughout the day. for crown heights north and east village only few rides are undertaken to far distance destinations in the morning and midday time window (gray areas representing w o,d < w min ). in the evening, more rides are requested overall, also to far distance destinations. overall, the qualitative patterns of ridesharing adoption do not vary significantly with the time of day (compare fig. across the full set of origin zones in new york city, supplementary figure suggests an overall trend to higher absolute demand for transportation services in the evening. the fraction of shared rides, however, is not affected by this trend. it is approximately constant throughout the day as illustrated in supplementary figure . the average standard deviation of fraction of rides shared across all taxi zones is less than . % between the three time windows, suggesting an equilibrated system. an aggregate analysis will naturally be dominated by the high overall demand in the evening and night time. still, the data suggests that the average ride-sharing adoption in new york city is stable across the day. hence, an aggregate analysis is representative. a linear scaling between s share and s indicates sufficient financial incentives to compensate the expected negative effects of ride-sharing with increasing demand. a decrease in slope and eventual saturation corresponds to a situation where financial incentives, expected detour and inconvenience are in balance. s share will not increase upon higher demand for given incentives (compare fig. in main manuscript as well as large s regime in supplementary fig. ). consider for example times square/theatre district and alphabet city (top left and bottom right): while for the first only approximately one in nine ride requests is shared, it is one in three for the latter. the spatial pattern of fraction of rides shared follows this trend. it is similar for regions with saturated shared ride request rate and starts to deviate the more the origin zone resembles a high-sharing regime (compare fig. fig. in the main manuscript). ride-sharing is only fully adopted if the financial discount compensates the expected inconvenience fully (full-sharing, dark blue). otherwise, the adoption of ridesharing decreases with increasing number of users s (partial sharing). c sharing decisions in chicago exhibit a hybrid state between low-and partial-sharing states (panel c, blue dots). at low request rates, the number of requests for shared rides increases linearly with the total number of requests. at higher request rates, the sharing decisions saturate (horizontal orange curve), indicating a partial sharing regime. few communities cross the horizontal branch, hinting at hardly any zones in a full-sharing regime, but generally low adoption of ride-sharing for the given financial incentives. the inset in panel c includes communities north east side, loop, near west side, lake view, west town, lincoln park, and trips originating outside of the boundaries of the city of chicago, whose request rates significantly exceed those of the other communities by up to one order of magnitude (not shown in the main panel, green border). in , three transportation service providers (uber, lyft, via) served more than million transportation service requests in the city of chicago, corresponding to approximately trips per day [ ] . in this supplementary note we demonstrate that the ride-sharing adoption in the city reproduces the hybrid sharing states observed for new york city and exhibits spatially heterogeneous patterns in ride-sharing adoption. chicago consists of community areas [ ] . supplementary fig. c illustrates request rate for shared rides as a function of the total request rate for rides. as illustrated for new york city in the main manuscript, chicago's different communities exhibit spatially heterogeneous ride-sharing adoption. while there exists a subset of communities for which the number of shared ride requests scales linearly in the total number of requests, other origin communities (e.g. lower west side, hyde park, uptown, near south side, o'hare) form a branch where the number of shared ride requests has saturated and does not increase with the overall number of ride requests. similarly to new york city, we observe partial and full-sharing regimes that give rise to spatially heterogeneous patterns of ride-sharing adoption (compare supplementary fig. c right) . other than in new york city, there are hardly any locations in the full-sharing regime indicated by the upper branch of ride-sharing adoption (compare supplementary fig. inset) . this means the different communities are in a partial-or non-sharing regime. in other words, financial discounts seem to be insufficient to compensate the inconvenience preferences in chicago, explaining that the majority of communities is not in a full-sharing state. the low number of locations on the upper branch suggests that a larger increase of the financial incentives is required to trigger the transition to the high-sharing regime to overcome the inconvenience preference ζ. in this supplementary note we formally define the ride-sharing anti-coordination game introduced in the main manuscript. we introduce a replicator dynamics governing the evolution of the population's willingness to share their rides. the resulting network dynamics unveils spatially heterogeneous sharing patterns, emerging from dynamic symmetry breaking. denote by g = (v, e) a mathematical graph of an urban street network composed of a node set v and an edge set e. nodes can be identified with individual intersection, census tracts or qualitatively similar zones embedded in space. edges correspond to streets connecting the different zones and are weighted by the geographical distance between them. the distance matrix d bundles the pairwise (shortest path) distances. in the following we consider a one-to-many setting where s people request transportation from a single origin o ∈ v to a destination d ∈ v \{o} on g. per destination node d ∈ v \{o} the probability π(d, t) ∈ [ , ] defines the local population's ride-sharing adoption when embarking from origin o at time t. π(d, t) is an aggregate measure for people's ride-sharing willingness, describing the average ride-sharing behavior of people with the same origin-destination combination. the ride-sharing adoption evolves under discrete-time replicator dynamics with reproduction factor where d single (d) = d o,d is the shortest path distance between origin o and destination d, d det (d) is the detour from sharing for destination d at time t and d inc (d, t) is the distance spent together on a shared ride. while the first distance is deterministic, the latter two are stochastic and depend on the overall demand for shared rides on the network. hence, they mediate a coupling between destinations on the network. a rescaling of eqn. ( ) shows that the dimensionless parameters ξ/ and ζ/ as well as . pairing rides is a maximum weight matching problem. the provider's matching algorithm solves the maximum weight matching problem. a a shared ride request graph defines potentially shareable rides σ share with edge weights defining the saved distance of a combined ride. b the provider pairs requests to maximize his saved distance. c per matching the provider defines the shared route to minimize the distance driven and customer inconvenience. the expected detour and inconvenience of shared rides originating from origin o ∈ v , going to destination d ∈ v , depend on (i) the configuration of destinations in the request set s at time t, (ii) the realization of sharing choices across all users, and (iii) the service provider's matching and routing algorithm. (i) origin-destination distribution. denote by σ ∈ v s the destination request configuration of the s simultaneous transportation requests from o. σ is a random variable governed by the origin-destination distribution w o . it impacts where users travel and which users may potentially be matched when sharing a ride. (ii) adoption of ride-sharing. depending on the user's individual decisions to share their rides, σ decomposes into σ share and σ single . the realization of destinations in σ share determines the potentially shareable rides. (iii) matching and routing algorithm. providers match ride requests based on distance savings potentials, which is equivalent to a maximum weight matching problem on a mathematical graph: shared ride requests define the nodes of this graph. if two rides offer a distance savings potential to the provider compared to two single rides, the ride requests are connected by an edge (see supplementary fig. a ). the distance savings potential defines the edge weight. here, we assume that both for single and shared ride requests the provider needs to return to the trip origin, consistent with the one-to-many setting. the provider's matching algorithm determines the matching of shared ride requests that maximizes the saved distance (see supplementary fig. b ). per matched request pair, the provider defines the trip route to minimize the distance driven. if he is indifferent whom to drop first, he will deliver the passenger with the shorter distance first to minimize customer inconveniences (see supplementary fig. c ). if, again, he is indifferent he tosses a fair coin to determine the order of the shared ride. while the adoption of ride-sharing in general depends on the underlying street network and the destination distribution, the problem simplifies in the limit of many concurrent users, s → ∞. in particular, a necessary and sufficient condition for full adoption of ride-sharing to be a stable equilibrium in this limit is that the financial incentives compensate the inconvenience (see supplementary fig. ). in this limit and with full sharing, detours disappear as users will always be matched with other users with the same destination. formally: theorem (full sharing in high-demand limit). if lim s→∞ π(d) * = the ratio of inconvenience to financial incentive must be ζ/ < . a dominant equilibrium strategy in sharing, π(d) * = , implies positive expected utility difference e[∆u(d) * ] > . the limit of infinite request number yields at ζc/ c = , a spatially heterogeneous pattern of ride-sharing adoption forms for finite s and detour preferences ξ > where adjacent branches alternate between the low-and high-sharing regimes. for ζ/ > ride-sharing adoption fades out along the branches that are still in the high-sharing regime. in the limit s → ∞ (or for ξ = ) the transition becomes discontinuous at ζc/ c = . simulation parameters: ξ = . , = . . where we used that π(d) * = for which s → ∞ corresponds to zero-detour matching to destination d. consequently, which implies ζ < . the case s = the case s = produces equilibrium adoption of ride-sharing qualitatively different than adjacent values of s, as discussed in figure a in the the main manuscript. for sufficiently high the population has a dominant sharing strategy in this configuration which is induced by the fact that the service provider can at most pair two of the three ride requests into a shared one. the left-over request will enjoy the benefits of a single ride at discounted trip fare, inducing an incentive to become this request which fuels both the ride-sharing adoption as well as the matching probability. as s increases beyond s = the incentive of gambling on being a left-over request reduces drastically as far less corresponding constellations exist. thus, s = produces a behavior in figure a of the main manuscript that looks qualitatively different than for other values of s. robustness of ride-sharing adoption for radially asymmetric origin-destination demand. radial asymmetry of the destination demand distribution does not qualitatively affect the equilibrium ride-sharing adoption. a dense core setting, inner ring destinations (gray shading) are visited twice as often as outer ring destinations. increased request rate reduces the destination's ride-sharing adoption from inside to outside. b urban sprawl setting, outer ring destinations (gray shading) are visited twice as often as inner ring destinations. as s increases the ride-sharing adoption ceases from outside to inside. in both cases branches of high ride-sharing adoption emerge in a random direction (compare fig. in all settings, the results are qualitatively the same as for homogeneous origin-destination demand (compare fig. in the main manuscript). naturally, sufficiently high financial incentives overcome this partial-sharing phase and result in full sharing, reproducing the two phases of ride-sharing adoption (see supplementary fig. robustness of ride-sharing adoption for azimuthally asymmetric origin-destination demand. an azimuthally asymmetric destination demand distribution predetermines the emergence of sharing/non-sharing branches. a sparse settlement setting, neighboring branches of destinations in radial direction alternate between being visited twice as likely (gray shading) as the other branches. the high-demand branches are sharing while the low demand branches quit sharing due to their high expected detour. increased request rate reduces the destination's ride-sharing adoption from inside to outside. b heterogeneous settlement setting, inner and outer ring destination nodes on the same branch alternate between being requested twice as often (gray shading) as the other one. also in this setting branches of high ride-sharing adoption emerge, driven by the outermost destinations. as s increases the ride-sharing adoption ceases from outside to inside (compare supplementary fig. b) . parameters: = . , ζ = . , ξ = . . in the one-to-many ride-sharing game, the relative position of the origin defines the scale of average distances to different destinations and the possible combinations in which requests for shared rides are matched. hence, it impacts expected detours and inconvenience. here, we consider the stylized city topology introduced in the main manuscript with a decentral origin at the periphery. supplementary figure illustrates a one-to-many situation of homogeneous transportation demand from the northernmost node in the stylized city topology. again, a distinct spatial pattern of ride-sharing adoption emerges in the partial sharing regime (supplementary fig. a ). when the financial incentives are sufficiently large, we recover the full sharing phase (supplementary fig. b ). in this setting, the sharing pattern is symmetric about the north-tosouth axis, where nodes in the direction of the city center share dominantly. they have no expected detours since in all constellations where they are matched, they will be dropped first. this is not the case anymore for destinations on the opposite side of the city center. hence, these destinations do not share. for the remaining destinations the decision to share, or not, results in a zero-sum game very soon as s increases (compare supplementary fig. a, center panel) and eventually reproduces a ride-sharing adoption pattern where neighboring branches alternate between sharing and not sharing (compare fig. in main manuscript). again, ride-sharing adoption behaves qualitatively similar compared to the constellation for central origins. goal : sustainbale cities and communities -target . : "...safe, affordable, accessible and sustainable transport systems traffic and related self-driven many-particle systems modelling the scaling properties of human mobility the hidden universality of movement in cities understanding individual human mobility patterns new developments in urban transportation planning intergovernmental panel on climate change. climate change mitigation of climate change european commission quantifying the benefits of vehicle pooling with shareability networks optimization for dynamic ride-sharing: a review addressing the minimum fleet problem in on-demand urban mobility scaling law of urban ride sharing topological universality of on-demand ride-sharing efficiency transportation sustainability follows from more people in fewer vehicles, not necessarily automation on-demand high-capacity ride-sharing via dynamic trip-vehicle assignment mean field theory of demand responsive ride pooling systems to share or not to share incentives and disincentives for ridesharing: a behavioral study. department of transportation, federal highway administration sharing the ride: a paired-trip analysis of uberpool and chicago transit authority services in chicago what do riders tweet about the people that they meet? analyzing online commentary about uberpool and lyft shared/lyft line the perfect uberpool: a case study on trade-offs ride-sharing efficiency and level of service under alternative demand, behavioral and pricing settings do transportation network companies decrease or increase congestion? towards demand-side solutions for mitigating climate change new york city taxi & limousine commission. congestion surcharge -tlc how mobility will shift in the age of us rideshare programs see supplementary information for details on data collection and treatment central loops in random planar graphs culture and low-carbon energy transitions anomalous supply shortages from dynamic pricing in on-demand mobility freezing by heating in a driven mesoscopic system chicago data portal -transportation network providers -trips. see supplementary information for details on data collection and treatment the replicator equation and other game dynamics fictitious play, shapley polygons, and the replicator equation blossom v: a new implementation of a minimum cost perfect matching algorithm world health organization. who announces covid- outbreak a pandemic weighted matchings in general graphs taxi & limousine commission chicago data portal -transportation network providers -trips we thank the network science group from the university of cologne and nora molkenthin for helpful discussions and christian dethlefs for help with simulations. d.s. acknowledges support from the studienstiftung des deutschen volkes. m.t. acknowledges support from the german research foundation (deutsche forschungsgemeinschaft, dfg) through the center for advancing electronics dresden (cfaed). in the main manuscript we demonstrated that the ride-sharing anti-coordination game reproduces opposing regimes of ride-sharing adoption in a simple setting. in this section we demonstrate the robustness of these results under different conditions, including non-homogeneous demand constellations and for different origin locations in the network, illustrating that the underlying mechanisms balancing incentives remain identical.ride-sharing adoption for non-homogeneous origin-destination demand using the stylized city topology introduced in the main manuscript, we investigate the impact of radially and azimuthally asymmetric destination demand on the ride-sharing adoption from a joint origin. we distinguish between four scenarios representative for different types of urban settlements: . dense core: starting from a joint origin in the city center, a gradient of decreasing destination demand in radial direction mimics urban environments with densely populated city core. further distance destinations (e.g. suburbs) are less often requested, e.g. because of sparser population density. urban sprawl : in situations where distant destinations from the city center make up the majority of ride requests the radial destination demand gradient is reversed. theses scenarios represent constellations of urban sprawl, or situations where the city core is only sparely populated, e.g. because of high real-estate prices. . sparse settlement: urban environments may exhibit azimuthal gradients in destination demand starting from an origin in the city center, e.g. stretched out residential settlements that have formed next to existing road, river banks etc. in that case destination demands in radial direction might be similar, but differ significantly by cardinal direction. heterogeneous settlement: urban constellations where both radial as well as azimuthal destination demand gradients exist might describe heterogeneously grown environments, e.g. because of natural obstacles or staged development.figs. and correspond to the four scenarios. for given financial discount an increase in request rate s gives rise to a spatially heterogeneous sharing/non-sharing pattern and decreasing overall adoption of ride-sharing in all scenarios, independent of the destination demand distributions (compare fig. in the main manuscript). as second order effects, the origin-destination distribution determines (i) whether the cardinal direction of the sharing pattern is random ( supplementary fig. for radially asymmetric destination demand), or aligned with the highest destination demand ( supplementary fig. for azimuthally asymmetric destination demand), and (ii) whether close-by or distant destinations reduce their willingness to share first upon increased request rate. . dense core: for dense core settings (see supplementary fig. a ) the cardinal direction of the sharing/nonsharing pattern is solely driven by random fluctuations breaking the azimuthal symmetry. the destination demand gradient leads to a reduction of willingness to share from inside to outside as s increases. . urban sprawl : phenomenologically, urban sprawl (see supplementary fig. b ) corresponds to dense core, but this time increasing the request rate reduces the willingness to share from the outside (i.e. high destination demand). in the presence of azimuthal destination demand gradients the sharing pattern forms along the branches of high demand (see supplementary fig. a ). the dominance of those destinations in the replicator dynamics guides the symmetry breaking into letting low demand destinations reduce their willingness to share, which reduces the expected detour for sharing branches. as s increases the willingness to share reduces from in-to outside as in the uniform case analyzed in the main manuscript. in this section of the supplementary information we provide detailed insight into the data used, cleansing procedures applied and simulation methods implemented. data sources. the new york city taxi & limousine commission (tlc) publishes trip records for high-volume for-hire vehicles (hvfhv) on a monthly basis. the data includes trip information on pickup time, origin zone, drop-off time, destination zone as well as a shared ride request label for providers completing more than trips per day [ ] . our analysis is based on the aggregate hvfhv activity between january and december , independent of service provider, including more than million transportation services. we exclude older data due to regulatory changes effective in [ ] , potentially impacting ride-hailing behavior, and data from due to changed transportation service activity in the course of the covid- pandemic [ ] .tlc partitions new york city into taxi zones and provides geospatial information about zone boundaries, names and jurisdictions [ ] . we adopt the definition of these zones in all of our analyses.additionally, the city of chicago publishes ride-hailing trip records on its open data portal [ ] . the data contains, amongst others, information about trip origin, destination, pickup and dropoff times as well as information whether a shared ride has been authorized by the requester. our analysis encompasses the time-span between january and december , as chosen for new york city, and includes more than million trip requests served by three transportation service providers (uber, lyft, via).in our geospatial analysis we restrict ourselves to chicago's community areas, as well as trips leaving or entering the official city borders.data preparation. we use tlc's data as-is. our data cleansing procedure removes trip records for which trip information is decoded as not available. furthermore, we omit trip records for zones and in our analysis. while the dataset contains trip requests labeled by these zones, there is no geographic decoding specified by tlc, nor do the zones have names.similarly, we use the chicago trip records as-is. for our analyses, we determine the total flux matrix specified in eqn. ( ) per city. when showing daily averages we normalize the total annual flux between origin and destination zones o and d by hour days to obtain a per-minuterequest rate, assuming hardly any request activity for hours per day. in case of specifically defined time windows (see supplementary note and ), we normalize the total flux by the window size.we compute the fraction of shared as specified in eqn. ( ) . equilibration. in this article, we focus on the equilibrium properties of the replicator dynamics underlying the ridesharing game on networks. to equilibrate the system we evolve eqn. ( ) . we discard a transient of replicator time steps before starting measurements of equilibrium values of observables.per replicator time step and per destination node we repeat the ride-sharing game for times for the current configuration of π(d, t) to generate a reliable numerical estimate for the expected utility increment of sharing e[∆u(d, t)] that is being used to update π(d, t + ).matching. after generating the shared ride request graph (see supplementary note ) we implement edmond's blossom algorithm to determine a maximum weight matching [ ] . since the algorithm used implements a minimum cost perfect matching, we reduce our non-perfect matching problem to a perfect one as described in [ , ch. . . ] . key: cord- -hly ne authors: danko, david; bezdan, daniela; afshinnekoo, ebrahim; ahsanuddin, sofia; bhattacharya, chandrima; butler, daniel j; chng, kern rei; donnellan, daisy; hecht, jochen; kuchin, katerina; karasikov, mikhail; lyons, abigail; mak, lauren; meleshko, dmitry; mustafa, harun; mutai, beth; neches, russell y; ng, amanda; nikolayeva, olga; nikolayeva, tatyana; png, eileen; ryon, krista; sanchez, jorge l; shaaban, heba; sierra, maria a; thomas, dominique; young, ben; abudayyeh, omar o.; alicea, josue; bhattacharyya, malay; blekhman, ran; castro-nallar, eduardo; cañas, ana m; chatziefthimiou, aspassia d; crawford, robert w; de filippis, francesca; deng, youping; desnues, christelle; dias-neto, emmanuel; dybwad, marius; elhaik, eran; ercolini, danilo; frolova, alina; gankin, dennis; gootenberg, jonathan s.; graf, alexandra b; green, david c; hajirasouliha, iman; hernandez, mark; iraola, gregorio; jang, soojin; kahles, andre; kelly, frank j; knights, kaymisha; kyrpides, nikos c; Łabaj, paweł p; lee, patrick k h; leung, marcus h y; ljungdahl, per; mason-buck, gabriella; mcgrath, ken; meydan, cem; mongodin, emmanuel f; moraes, milton ozorio; nagarajan, niranjan; nieto-caballero, marina; noushmehr, houtan; oliveira, manuela; ossowski, stephan; osuolale, olayinka o; Özcan, orhan; paez-espino, david; rascovan, nicolas; richard, hugues; rätsch, gunnar; schriml, lynn m; semmler, torsten; sezerman, osman u; shi, leming; shi, tieliu; song, le huu; suzuki, haruo; tighe, scott w; tong, xinzhao; udekwu, klas i; ugalde, juan a; valentine, brandon; vassilev, dimitar i; vayndorf, elena; velavan, thirumalaisamy p; wu, jun; zambrano, maría m; zhu, jifeng; zhu, sibo; mason, christopher e title: global genetic cartography of urban metagenomes and anti-microbial resistance date: - - journal: biorxiv doi: . / sha: doc_id: cord_uid: hly ne although studies have shown that urban environments and mass-transit systems have distinct genetic profiles, there are no systematic worldwide studies of these dense, human microbial ecosystems. to address this gap in knowledge, we created a global metagenomic and antimicrobial resistance (amr) atlas of urban mass transit systems from cities, spanning , samples and , taxonomically-defined microorganisms collected for three years. this atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance markers, and novel genetic elements, including , novel predicted viral species, novel bacteria, and novel archaea. urban microbiomes often resemble human commensal microbiomes from the skin and airways, but also contain a consistent “core” of species which are predominantly not human commensal species. samples show distinct microbial signatures which may be used to accurately predict properties of their city of origin including population, proximity to the coast, and taxonomic profile. these data also show that amr density across cities varies by several orders of magnitude, including many amrs present on plasmids with cosmopolitan distributions. together, these results constitute a high-resolution, global metagenomic atlas, which enables the discovery of new genetic components of the built human environment, highlights potential forensic applications, and provides an essential first draft of the global amr burden of the world’s cities. introduction limitations in sequencing depth, or by missing annotations in the reference databases used for taxonomic classification, which is principally problematic with phages. it is worth noting that potentially prevalent presence and absence of species (which is robust to noise from relative abundance) and performed a dimensionality reduction of the data using umap (uniform manifold approximation and projection, mcinnes et al. ( )) for visualization (figure a) . jaccard distance was correlated with distance based on jensen-shannon divergence (which accounts for relative abundance) and k-mer distance calculated by mash (which is based on the k-mer distribution in a sample, so cannot be biased by a database) (supp. figure s a , b, c). in principle, jaccard distance could be influenced by read depth as low abundance species drop below detection thresholds. however we expect this issue to be minor as the total number of species identified stabilized at , reads (supp. figure s b ) compared to an average of . m reads per sample. samples collected from north america and europe were distinct from those collected in east asia, but the separation between other regions was less clear. a similar trend was found in an analogous analysis based on functional pathways rather than taxonomy (supp. fig s d) , which indicates geographic stratification of the metagenomes at both the functional and taxonomic levels. subclusters identified by umap roughly corresponded to city and climate but not surface type (supp. figure we quantified the degree to which metadata covariates influence the taxonomic composition of our samples using mavric, a statistical tool to estimate the sources of variation in a count-based dataset (moskowitz and greenleaf, ). we identified covariates which influenced the taxonomic composition of our samples: city, population density, average temperature in june, region, elevation above sea-level, surface type, surface material, elevation above or below ground and proximity to the coast. the most important factor, which could explain % of the variation in isolation, was the city from which a sample was taken followed by region which explained %. the other four factors ranged from explaining % to % of the possible variation in taxonomy in isolation (supp . table s ). we note that many of the factors were confounded with one another, so they can explain less diversity than their sum. one metadata factor tested, the population density of the sampled city, had no significant effect on taxonomic variation overall. to quantify how the principle covariates, climate, continent, and surface material impacted the taxo- nomic composition of samples, we performed a principal component analysis (pca) on our taxonomic data normalized by proportion and identified principal components (pcs) which were strongly associated with a metadata covariate in a positive or negative direction (pcs were centered so an average direction indicates an association). we found that the first two pcs (representing . % and . % of the variance of the original data, respectively) associated strongly with the city climate while continent and surface material associate less strongly (figure b) . next, we tested whether geographic proximity (in km) of samples to one another had any effect on the variation, since samples taken from nearby locations could be expected to more closely resemble one another. indeed, for samples taken in the same city, the average jsd (jensen-shannon distance) was weakly predictive of the taxonomic distance between samples, with every increase of km in distance between two samples representing an increase of . % in divergence (p < e , r = . , supp. figure s b ). this suggests a "neighborhood effect" for sample similarity analogous to the effect described by meyer et al. ( ) , albeit a very minor one. to reduce bias that could be introduced by samples colored by the region of origin for each sample. axes are arbitrary and without meaningful scale. the color key is shared with panel b. b) association of the first principal components of sample taxonomy with climate, continent, and surface material. c) distribution of major phyla, sorted by hierarchical clustering of all samples and grouped by continent. d) distribution of high-level groups of functional pathways, using the same order as taxa (c). e) distribution of amr genes by drug class, using the same order as taxa (c) . note that mls is macrolide-lincosamide-streptogramin. taken from precisely the same object we excluded all pairs of samples within km of one another. at a global level, we examined the prevalence and abundance of taxa and their functional profiles between cities and continents. these data showed a fairly stable phyla distribution across samples, but the relative abundance of these taxa is unstable (figure c ) with some continental trends. in contrast to taxonomic variation, functional pathways were much more stable across continents, showing relatively little variation in the abundance of high level categories (figure d ). this pattern may also be due to the more limited range of pathway classes and their essential role in cellular function, in contrast to the much more wide-ranging taxonomic distributions examined across metagenomes. classes of antimicrobial resistance were observed to vary by continent as well. clusters of amr classes were observed to occur in groups of taxonomically similar samples ( figure e ). we quantified the relative variation of taxonomic and functional profiles by comparing the distribution of pairwise distances in taxonomic and functional profiles. both profiles were equivalently normalized to give the probability of encountering a particular taxon or pathway. taxonomic to facilitate characterization of novel sequences we created geodna, a high-level web interface (figure a) to search raw sequences against our dataset. users can submit sequences to be processed against a k-mer graph-based representation of our data. query sequences are mapped to samples and a set of likely sample hits is returned to the user. this interface will allow researchers to probe the diversity in this dataset and rapidly identify the range of various genetic sequences. we sought to determine whether a samples taxonomy reflected the environment in which it was collected. to this end we trained a random forest classifier (rfc) to predict a sample's city of origin from its taxonomic profile. we trained an rfc with components on % of the samples in our dataset and evaluated its classification accuracy on the remaining %. we repeated this procedure with multiple subsamples of our data at various sizes and with replicates per size to achieve a distribution (fig. b ). the rfc achieved % on held out data which compares favorably to the . % that would be achieved by a randomized classifier. these results from our rfc demonstrate that city specific taxonomic signatures exist and can be predictive. we expanded our analysis of environmental signatures in taxonomy to the prediction of features in cities not present in our training set. to do this we collated a set of features for each city: population, surface material, elevation, proximity to the coast, population density, region, ave june temperature, and koppen climate classification. we trained a rfcs to predict each feature based on all samples that were not taken from a given city then used the relevant rfc to predict the feature for samples from the held out city and recorded the classification accuracy ( figure d ). while not all features and cities were equally predictable (in particular features for a number of british cities were roughly similar and could be predicted effectively) in general the predictions exceeded random chance by a significant margin (supp. figure s a ). this suggests that certain features of cities generate microbial signatures that are present globally and distinct from city specific signatures. the successful geographic classification of samples demonstrates distinct city-specific trends in the detected taxa, that may enable future forensic biogeographical capacities. however, unique, city-specific taxa are not uniformly distributed ( figure b ). to quantify this, we developed a score to reflect how endemic a given taxon is within a city, which reflects upon the forensic usefulness of a taxon. we define the endemicity score (es) of a taxa as term-frequency inverse document frequency where the document consists of samples from some metadata defined group such as a city or region. this score is designed to simultaneously reflect the chance that a taxon could identify a given city and that that taxon could be found within the given city. a high es for a taxon in a given city could be evidence of the evolutionary advantage that the taxon has in a particular cities environment. however, neutral evolution of microbes within a particular niche is also possible and the es alone does not distinguish between these two hypotheses. note that while the es only considers taxa which are found in a city, a forensic classifier could also take advantage of the absence of taxa for a similar metric. es show a roughly bimodal distribution for regions (fig. c) . each region possesses a number of taxa with es scores close to and a slightly larger samples for all cities are transformed into lists of unique k-mers (left). after filtration, the k-mers are assembled into a graph index database. each k-mer is then associated with its respective city label and other informative metadata, such as geo-location and sampling information (top middle). arbitrary input sequences (top right) can then be efficiently queried against the index, returning a ranked list of matching paths in the graph together with metadata and a score indicating the percentage of k-mer identity (bottom right). the geo-information of each sample is used to highlight the locations of samples that contain sequences identical or close to the queried sequence (middle right). b) classification accuracy of a random forest model for assigning city labels to samples as a function of the size of training set. c) distribution of endemicity scores (term frequency inverse document frequency) for taxa in each region. d) prediction accuracy of a random forest model for a given feature (rows) in samples from a city (columns) that was not present in the training set. rows and columns sorted by average accuracy. continuous features (e.g. population) were discretized. number close to (note that es is not bounded in [ , ]). some cities, like offa (nigeria), host many unique taxa while others, like zurich (switzerland), host fewer endemic species (supp. figure s b ). large numbers of endemic species in a city may reflect geographic bias in sampling. however, some cities from well sampled continents (e.g., lisbon, hong kong) also host many endemic species which would suggest that es may indicate interchangeability and local pockets of microbiome variation for some locations. quantification of antimicrobial diversity and amrs are key components of global antibiotic stewardship. yet, predicting antibiotic resistance from genetic sequences alone is challenging, and detection accuracy depends on the class of antibiotics (i.e., some amr genes are associated to main metabolic pathways while others are uniquely used to metabolize antibiotics). as a first step towards a global survey of antibiotic resistance in urban environments, we mapped reads to known antibiotic resistance genes, using the megares ontology and alignment software. we quantified their relative abundance using reads/kilobase/million mapped reads (rpkm) for classes of antibiotic resistance genes detected in our samples (figure a b) . , samples had some sequence which were identified as belonging to an amr gene, but no consistent core set of genes was identified. the most common classes of antibiotic resistance genes were for macrolides, lincosamides, streptogamines (mls), and betalactams, yet the most common class of antibiotic resistance genes, mls was found in only % of the samples where amr sequence was identified. despite being relatively common, antibiotic resistance genes were universally in low abundance com- pared to functional genes, with rpkm values for resistance classes typically ranging from . - com- pared to values of - for typical housekeeping genes (amr classes contain many genes so rpkm values may be lower than they would be for individual genes). in spite of the low abundance of the genes themselves, some samples contained sequences from hundreds of distinct amr genes. clusters of high amr diversity were not evenly distributed across cities ( figure c ). some cities had more resistance genes identified on average ( - x) than others (e.g. bogota) while other cities had bimodal distribu- tions (e.g. san francisco) where some samples had hundreds of genes while others very few. we note that % of the cases where we detected an amr genes had an average depth of . x, indicating that our global distribution would not dramatically change with altered read depth (supp. figure s e ). as with taxa, amr genes can be used to classify samples to cities -albeit with much less accuracy. a random forest model analogous to the one trained to predict city classification from taxonomic profiles was trained to predict from profiles of antimicrobial resistance genes. this model achieved . % accuracy on held out test data (supp. figure s a ). while poor for actual classification this accuracy far exceeds the . % that would be achieved by randomly assigning labels and indicates that there are possibly weak, city specific signatures for antimicrobial resistance genes. multiple amr genes can be carried on a single plasmid and ecological competition may cause mul- tiple taxa in the same sample to develop antimicrobial resistance. as a preliminary analysis into these phenomenons we identified clusters of amr genes that co-occurred in the same samples ( figure d ). we measured the jaccard distance between all pairs of amr genes found in at least % of samples and performed agglomerative clustering on the resulting distance matrix. we identified three large clusters of genes and numerous smaller clusters. of note, these clusters often consist of genes from multiple classes of resistance. at this point we do not posit a specific ecological mechanism for this co-occurrence, but we note that the large clusters contain far more genes than are typically found on plasmids. we performed a rarefaction analysis on the set of all resistance genes in the dataset, which we call the "panresistome" (figure (supp. figure s b ). similar to the rate of detected species, the panresistome also shows an open slope with an expected rate of discovery of previously unobserved amr gene per samples. given that amr gene databases are rapidly expanding and that no amr genes were found in some samples, it is likely that future analyses will identify many more resistance genes in this data. additionally, amr genes show a "neighbourhood" effect within samples that are geographically prox- imal analogous to the effect seen for taxonomic composition (supp. figure s c ). excluding samples where no amr genes were detected, the jaccard distance between sets of amr genes increases with distance for pairs of samples in the same city. as with taxonomic composition. the overall effect is weak and noisy, but significant. to examine these samples for novel genetic elements, we assembled and identified metagenome assembled genomes (mags) for viruses, bacteria, and archaea and analyzed them with several algorithms. this includes thousands of novel crispr arrays that reflect the microbial biology of the cities and , genomes from our data, of which did not match any known reference genome within % average nucleotide identity (ani). of the genomes were classified as bacteria, and as archaea. bacterial genomes came predominantly from four phyla: the proteobacteria, actinobacteria, firmicutes, and bacteroidota. novel bacteria were evenly spread across phyla ( figure a ). assembled bacterial genomes were often identified in multiple samples. several of the most prevalent bacterial genomes were novel species ( figure b ). some assembled genomes, both novel and not, showed regional specificity while others were globally distributed. the taxonomic composition of identifiable genomes roughly matched the composition of the core urban microbiome (section ). the number of identified bacterial mags was somewhat based on read depth and the sample count per city (supp. figure s a ). the number of bacterial mags discovered in a city which did not match a known species was closely correlated to the total number of bacterial mags discovered in that city (supp. figure s b ). bacterial mags were roughly evenly distributed geographically with the notable exception of offa, which had dramatically more novel bacterial species than other cities. we investigated assembled contigs from our samples to identify , predicted uncultivated viral genomes (uvigs). taxonomic analysis of predicted uvigs to identify viral species yielded , clusters containing a total of , uvigs and , singleton uvigs for a total of , predicted viral species. we compared the predicted species to known viral sequences in the jgi img/vr system, which contains viral genomes from isolates, a curated set of prophages and k viral mags from other studies. of the , species discovered in our data . % did not match any viral sequence in img/vr (paez- espino et al., ) at the species level for a total of , novel viruses. we note that this number is surprisingly high but was obtained using a conservative pipeline ( . % precision) and corresponded well with our identified crispr arrays (below). this suggests that urban microbiomes contain significant diversity not observed in other environments. next, we attempted to identify possible bacterial and eukaryotic hosts for our predicted viral mags. for the species with similar sequences in img/vr, we projected known host information onto , metasub viral mags. additionally, we used crispr-cas spacer matches in the img/m system to assign possible hosts to a further , predicted viral species. finally, we used a database of million metagenome-derived crispr spacers to provide further rough taxonomic assignments. our predicted viral hosts aligned with our taxonomic profiles, % of species in the core microbiome (section ) had predicted viral-host interactions. many of our viral mags were found in multiple locations ( figure d ). many viruses were found in south america, north america and africa. viral mags in japan often corresponded to those in europe and north america. we identified , crispr arrays in our data of which , could be annotated for specific systems. the annotated crispr arrays were principally type -e and -f btu a number of type two and three systems were identified as well ( figure e , f). a number of arrays had unclear or ambiguous type assignment. critically the spacers in our identified crispr arrays closely matched our predicted viral mags. we aligned spacers to both our viral mags and all viral sequences in refseq. the total fraction of spacers which could be mapped to our viral mags and refseq was similar (supp. figure s c) but the mapping rate to our viral mags dramatically exceeded the mapping rate to refseq (figure c). we present this as additional evidence supporting these novel viral mags. (tables and s ) , constituting the first large scale metagenomic study of the urban microbiome. we also identified species that are geographically constrained and showed that these can be used to determine a samples city of origin (section . ). many of these species are associated with commensal microbiomes from human skin and airways, but we observed that urban microbiomes are nevertheless distinct from both human and soil microbiomes. notably, no species from the bacteroidetes, a prominent group of human commensal organisms (eckburg et al., ; qin et al., ) , was identified in the core urban microbiome. we conclude that there is a consistent urban microbiome core ( figure , ), which is supplemented by geographic variation (figure ) and microbial signatures based on the specific attributes of a city ( figure ). our data also indicates that significant diversity remains to be characterized and that novel taxa may be discovered in the data (figure ), that environmental factors affect variation, and that sequences associated with amr are globally widespread but not necessarily abundant ( figure ). in addition to these results, we present several ways to access and analyze our data including interactive web based visualizations, search tools over raw sequence data, and high level interfaces to computationally access results. unique taxonomic composition and association with covariates specific to the urban environment suggest that urban microbiomes should be treated as ecologically distinct from both surrounding soil microbiomes and human commensal microbiomes. though these microbiomes undoubtedly interact with the urban environment, they nonetheless represent distinct ecological niches with different genetic profiles. while our metadata covariates were associated with the principal variation in our samples, they do not explain a large proportion of the observed variance. it remains to be determined whether variation is essentially a stochastic process or if a deeper analysis of our covariates proves more fruitful. we have observed that less important principal components (roughly pcs - ) are generally less associated with metadata covariates but that pcs - do not adequately describe the data alone. this is a pattern that was observed in the human microbiome project as well, where minor pcs (such as our figure b ) were required to separate samples from closely related body sites. much of the urban microbiome likely represents novel diversity as our samples contain a significant in addition to general purpose data analysis tools essentially all analysis in this paper is available as a series of jupyter notebooks. our hope is that these notebooks allow researchers to reproduce our results, build upon our results in different contexts, and better understand precisely how we arrived at our conclusions. by providing the exact source used to generate our analyses and figures, we also hope to be able to quickly incorporate new data or correct any mistakes that might be identified. for less technical purposes, we also provide web-based interactive visualizations of our dataset (typ- ically broken into city-specific groups). these visualizations are intended to provide a quick reference for major results as well as an exploratory platform for generating novel hypotheses and serendipitous discovery. the web platform used, metagenscope, is open source, permissively licensed, and can be run on a moderately powerful machine (though its output relies on results from the metasub cap). our hope is that by making our dataset open and easily accessible to other researchers the scientific community can more rapidly generate and test hypotheses. one of the core goals of the metasub consortium is to build a dataset that benefits public health. as the project develops we want to make our data easy to use and access for clinicians and public health officials who may not have computational or microbiological expertise. we intend to continue to build tooling that supports these goals. fields collected were the location of sampling, the material being sampled, the type of object being sampled, the elevation above or below ground, and the station or line where the sample was collected. however, several cities were unable to use the provided apps for various reasons and submitted their metadata as separate spreadsheets. additionally, certain metadata features, such as those related to sequencing and quality control, were added after initial sample collection. to collate various metadata sources, we built a publicly available program which assembled a large master spreadsheet with consistent sample uuids. after assembling the originally collected data at- ), which we have added to an empty sterile urine cup followed by swabbing for min (fig.s ). furthermore, the working space has been swabbed for . min / min before and after treatment with % bleach (fig. s ) figure s ). distributions of dna concentration and the number of reads were as expected. gc content was broadly distributed for negative controls while positive controls were tightly clustered, expected since positive controls have a consistent taxonomic profile. comparing the number of reads before and after quality control did not reveal any major outliers. . . batch effect appears minimal a major concern for this low-biomass studies and large-scale studies are batch effects. the median flowcell used in our study contained samples from cities and continents. however, two flowcells covered cities from or continents respectively. when samples from these flowcells were plotted using umap (see section . for details) the major global trends we described were recapitulated (supp. we used blastn to align nucelotide assemblies from case samples to control samples. we used a threshold of , base pairs and . % identity as a minimum to consider two sequences homologous. this threshold was chosen to be sensitive without solely capturing conserved regions. we identified all connected groups of homologous sequences and found approximate taxonomic identifications by aligning contigs to ncbi-nt using blastn searching for % nucleotide identity over half the length of the longest contig in each group. section ). our dilemma was that a microbial species that is common in the urban environment might also reasonably be expected to be common in the lab environment. in general, negative controls had lower k-mer complexity, fewer reads, and lower post pcr qubit scores than case samples and no major previous studies have reported that microbial species whose relative abundance is negatively cor- related with dna concentration may be contaminants. we observed a number of species that were negatively correlated with dna concentration (supp. figure s a ) but this distribution followed the same shape (but had a greater magnitude) as a null distribution of uniformly randomly generated rela- tive abundances (supp. figure s b ) leading us to conclude that negative correlation may simply be a statistical artifact. we also plotted correlation with dna concentration against each species mean rela- tive abundance across the entire data-set (supp. figure s c ). species that were negatively correlated with dna concentration were clearly more abundant than uncorrelated species, this suggests that there may be a jackpot effect for prominent species in samples with lower concentrations of dna but is not generally consistent with contamination. we analyzed the total complexity of case samples in comparison to control samples. case samples had a significantly higher taxonomic diversity (supp. figure s a ) than any type of negative control sample. we also compared the confidence of taxonomic assignments to control assignments for prominent taxa (supp. figure s b ) using the number of unique marker k-mers to compare assignments. we found that case samples had more and higher quality assignments than could be found in controls. one species, bradyrhizobium sp. btai , was not clearly better in case samples than controls but in this case we were able to assemble genomes for this species in several unique samples so we feel it is ambiguous. finally, we compared assemblies from negative controls to assemblies from our case samples searching for regions of high similarity that could be from the same microbial strain. we reasoned that uncontam- inated samples may contain the same species as negative controls but were less likely to contain identical strains. only case samples were observed to have any sequence with high similarity to an assem- bled sequence from a negative control ( , base pairs minimum of . % identity). the identified sequences were principally from bradyrhizobium and cutibacterium. since these genera are core taxa (see section ) observed in nearly every sample but high similarity was only identified in a few samples, we elected not to remove species from these genera from case samples. we generated -mer profiles for raw reads using jellyfish. all k-mers that occurred at least twice in a given sample were retained. we also generated mash sketches from the non-human reads of each sample with million unique minimizers per sketch. we calculated the shannon's entropy of k-mers by sampling -mers from a uniform , reads per sample. shannon's entropy of taxonomic profiles was calculated using the capalyzer package (section ). . . k-mer based metrics correlate with taxonomic metrics we found clear correlations between three pairwise distance metrics (supp. figure s a , b, c): k-mer based jaccard distance (mash), taxonomic jaccard distance, and taxonomic jensen-shannon diver- gence. this suggests that taxonomic variation reflects meaningful variation in the underlying sequence in a sample. we also compared alpha diversity metrics (supp. figure s d ): shannon entropy of k-mers, and shannon entropy of taxonomic profiles. as with pairwise distances these metrics were correlated though noise was present. this noise may reflect sub-species taxonomic variation in our samples. and mapped these to a set of large database using blastn (see for details). this resulted in . % reads which could not be mapped to any external database compared to . % of reads mapped using our approach with krakenuniq. we note that our approach to estimate the fraction of reads that could be classified using blastn does not account for hits to low quality taxa which would ultimately be discarded in our pipeline, and so represents a worst-case comparison. explanation ( ) as it has been demonstrated to be comparable or having higher sensitivity than the best tools identified in a recent benchmarking study (mcintyre et al. ( ) ) on the same comparative dataset. in addition, krakenuniq allows for tunable specificity and identifies k-mers that are unique to particular taxa in a database. reads are broken into k-mers and searched against this database. finally, the taxonomic makeup of a sample is given by identifying the taxa with the greatest leaf to ancestor weight. krakenuniq reports the number of unique marker k-mers assigned to each taxon, as well as the total number of reads, the fraction of available marker k-mers found, and the mean copy number of those k-mers. we found that requiring more k-mers to identify a species resulted in a roughly linear decrease at a minimum we required three reads assigned to a taxa with unique marker k-mers. this setting captures a group of taxa with low abundance but reasonable (∼ - %) coverage of the k-mers in their marker set (supp. figure s c ). however, this also allows for a number of taxa with very high ( ) duplication of the identified marker k-mers and very few k-mers per read which we believe is biologically implausible (supp. figure s d ). we filtered these taxa by applying a further filter which required that the number of reads not exceed times the number of unique k-mers, unless the set of unique k-mers was saturated (> % completeness). we include a full list of all taxonomic calls from all samples including diagnostic values for each call. we do not attempt to classify reads below the species level in this study. we further evaluated prominent taxonomic classifications for sequence complexity and genome cov- figure s b ). we chose sub-sampling (sometimes referred to as rarefaction in the literature) based on the study by weiss et al. ( ) , showing that sub-sampling effectively estimates relative abundance. note that we use the term prevalence to describe the fraction of samples where a given taxon is found at any abundance and we use the term relative abundance to describe the fraction of dna in a sample from a given taxon. we compared our samples to metagenomic samples from the human microbiome project and a metagenomic study of european soil samples using mash (ondov et al., ) , a fast k-mer based comparison tool. we built mash sketches from all samples with million unique k-mers to ensure a sensitive and accurate comparison. we used mash's built-in jaccard distance function to generate distances between our samples and hmp samples. we then took the distribution of distances to each particular human commensal community as a proxy for the similarity of our samples to a given human body site. we also compared our samples to hmp and soil samples using taxonomic profiles generated by metaphlan v . (segata et al., ) . we generated taxonomic profiles from non-human reads using metaphlan v . and found the cosine similarity between all pairs of samples. we used the microbe directory (shaaban et al., ) we analyzed the metabolic functions in each of our samples by processing non-human reads with hu- mann (franzosa et al., ) . we aligned all reads to uniref using diamond (v . . , (buchfink et al., ) ) and used humann to produce estimate of pathway abundance and completeness. we filtered all pathways that were less than % covered in a given sample but otherwise took the reported pathway abundance as is after relative abundance normalization (using humann 's attached script). high level categories of functional pathways were found by grouping postively correlated pathways and manually annotating resulting clusters. figure s : ecological relationships with taxa. a) correlation between species richness and latitude. richness decreases significantly with latitude b) neighbourhood effect. taxonomic distance weakly correlates with geographic distance within cities. c) fraction of reads assigned to different databases by blast for each region, at different levels of average nucleotide identity figure s : antimicrobial resistance genes, supplemental. a) classification accuracy of a random forest model predicting city labels for held out samples from antimicrobial resistance genes. b) rarefaction analysis of antimicrobial resistance genes. curve does not flatten suggesting we would identify more amr genes with more samples. c) neighbourhood effect. jaccard distance of amr genes weakly correlates with geographic distance within cities. d) number of amr genes detected for samples in each region. e) distribution of reads per gene (normalized by kilobases of gene length) for amr gene calls. the vertical red line indicates that % of amr genes have more than . reads per kilobase and would still be called at a lower read depth. gaussian distributions to sampling locations where the taxa was found with standard deviations based on the geographic distance between observations. top row) sampling sites in three major cities rows - ) estimated distribution of different example species in major cities row ) estimated distribution of three species together in major cities structure, function and diversity of the healthy human microbiome metaspades: a new versatile metagenomic assembler nala an, núria andreu so- mavilla a) number of species detected as k-mer threshold increases for randomly selected samples b) number of species detected as number of sub-sampled reads increase c) k-mer counts compared to number of reads for species level annotations in randomly selected samples, colored by coverage of marker k-mer set d) k-mer counts compared to number of reads for species level annotations in randomly selected samples, colored by average duplication of k-mers e) comparison of mean sequence entropy and coverage equality for core and sub-core taxa a) jensen-shannon divergence of taxonomic profiles vs mash jaccard distance of k-mers b) divergence of taxonomic profiles vs jaccard distance of taxonomic profiles. c) jaccard distance of taxonomic profilesvs mash jaccard distance of k-mers d) shannon's entropy of taxonomic profiles vs shannon's entropy of k-mers e) taxonomic richness (number of species) vs shannon's entropy of taxonomic profiles figure s : a) mash k-mer jaccard similarity to representative hmp samples metaphlan v . cosine similarity to representative hmp samples, colored by continent c) fraction unclassified dna by surface material d) cosine similarity to metaphlan v . skin microbiome profile by surface e) jensen-shannon distance between pairs of taxonomic profiles vs geographic distance f) mash k-mer jaccard similarity to representative soil samples key: cord- -xv gtwzt authors: abdalla, rifaat; tao, c. vincent; li, jonathan title: challenges for the application of gis interoperability in emergency management date: journal: geomatics solutions for disaster management doi: . / - - - - _ sha: doc_id: cord_uid: xv gtwzt this paper highlights application challenges for gis interoperability for emergency management with emphasis on critical infrastructure sectors. in the first part, this paper provides a comparative analysis of emergency management operations in the city of vancouver; the city of toronto, the kitchener waterloo region, and the dufferin county. a variety of qualitative research methods were employed for gathering information from key decision-makers involved with emergency management. the second part of this paper presents a scenario-based case study, which aims to provide a demonstration of the utility of gis interoperability, for disaster management. this paper also discusses the strengths and weaknesses of leveraging gis interoperability for disaster management. geographic information system (gis) interoperability aims to ensure a process that will allow for the use of data, information, and services across organizational boundaries, and to make information available for all of the levels involved in disaster management activities. one of the first studies that aimed to characterize gis interoperability was by bishr ( ) who has demonstrated the need for working on data that are scattered over sev-eral independent databases. this goal has been achieved and the internet has played the key role in connecting systems over a common network protocol. according to erharuyi and fairbairn ( ) , real-time ability to visualize map locations, determine the scale of emergency, identify and evacuate at-risk populations, and expedite and direct response efforts are key areas in which gis interoperability is much needed. as a result, a great deal of interest towards disaster management applications using internet gis is rapidly emerging. advancements in internet technology, in the form of high speed broadband, have made gis interoperability more effective and accessible. this paper will address issues related to gis interoperability, and will examine the status of gis interoperability in disaster management, with emphasis on specific ontario municipalities (i.e., toronto, kitchener waterloo and dufferin county). the second part of this paper will present an example (i.e., a demonstration case study) that highlights benefits that gis interoperability could bring to the disaster management community. gis interoperability is unique in that it allows one to ensure easy and compatible spatial data access over the internet (visser et al. ) . farley ( ) indicates that interoperability is important for disaster management applications, because it helps to eliminate system and data heterogeneity. the importance of this has made interoperability a central research and development initiative. according to goodchild ( ) interoperability aims to eliminate incompatibilities in data formats, software products, and spatial conceptions and data quality standards. the distinction between data transfer and interoperability is very important. table summarizes the differences between interoperability and transfer. table . differences between the process of data transfer and data interoperability (after glover ) . the concept of gis interoperability, as shown in (table ) is a process of using standard protocols to control inter-system access over the internet. disasters and their impacts may extend across large areas which, when dealing within a gis context, invariably involves large volumes of data. thus, simulating natural disasters may require advanced and high-capacity computing capabilities. satellite imagery, digital elevation models and vector data available to municipalities and to the provincial authorities may exceed the processing capacity of a desktop computer. this is one of the areas where the strength of network-centric computing and systems interoperability is required. interoperability can also allow efficient share of data / information in near real time when one is experiencing an emergency. the open geospatial consortium (ogc) is a us-based industry consortium, with members from government and academia that has a mandate to develop and foster interoperability specifications (ogc a) . ogc has initiated interoperability specifications. three of these specifications represent the backbone for gis interoperability, which are: web map service (wms) specification, which standardizes the process of requests and response between the server and the client for efficient data sharing. web feature service (wfs) which controls the process of basic edits over the internet. web coverage service (wcs) which standardizes the process of exploring coverage data. a comparative analysis of applications, resources and needs was conducted in order to examine the actual need for interoperable gis applications for disaster management. a focus was placed on the city of toronto, since it is one of the largest metropolitan centers in canada. the study compared toronto with similar selected medium and small-sized cities in canada. the city of vancouver was chosen on the basis of its comparable size, similar administrative structure and the similarity of operational activities related to emergency management. a questionnaire was carefully designed in order to address three issues, namely: ) usability of network-centric gis; ) gis interoperability appli-cations and examples; and ) issues and challenges related to having interoperating gis systems. the questionnaire was sent to each municipality and answers obtained either by email, or through conference call. the third part of this methodology involved providing an example showcase solution of the optimal application of interoperability for each of the municipalities studied. the developed application utilized datasets for the city of toronto obtained through the map library at york university, with digital elevation data and watershed information obtained from the toronto region conservation authority. the methodology used in this study is shown in fig. . the city of toronto is located on southeastern ontario, on a broad sloping plateau cut by numerous river valleys. toronto, one of the largest cities in canada, covers sq km, and stretches km from east to west and km from north to south at its longest points (wright et al. ) . the city of toronto has a department that is involved with emergency mapping; this is known as the department emergency mapping services. it was formed in as a result of the amalgamation of the municipalities of toronto, scarborough, and north york into the greater toronto area (gta). the emergency mapping services of the city of toronto is working toward an advanced level of interoperability that integrates data, processing and se-mantics in both applications and services. currently the department is using both desktop gis and web-based gis technologies for processing and coordinating disaster management activities. the staff of the mapping services department is comprised of over personnel ranging in responsibility from technical to management roles. the emergency mapping department is located in a three story facility. surprisingly, the funding for this facility is estimated to be less than % of the total budget of the city of toronto. web-based gis interoperability is thought to be critically important to the city of toronto, as evidenced by the fact that the city is moving all gis mapping services and applications toward web-based technologies. the best examples for incidents in which web-based gis interoperability was determined to be of great use to the city of toronto include: data exchange between local governments, exchange of data between government and business users, and exchange of data between government and utility companies. the it group at the city of toronto believes that web-based gis represents the coming generation of gis and that it will eventually be used ubiquitously. the emergency mapping department of the city of toronto is coordinating with civil society organizations that are working on the social dimensions of disaster management and emergency response aid in terms of cooperative data sharing, sharing common data exchange standards, and providing cross training of staff. a need for gis interoperability was demonstrated by the city of toronto on a variety of occasions. the most recent examples involved the modeling of west nile virus, and severe acute respiratory syndrome (sars). gis applications are very useful in modeling epidemic disease outbreaks, since gis provides the location information and diffusion patterns in visual databases. as well, it provides the desired level of coordination between health authorities, municipal authorities, and community decision-makers. the city of toronto has also used gis in planning for two massive festivals, namely: ( ) on world youth day in , and ( ) the rolling stones concert in . these two events were attended by hundreds of thousands of people. in case of emergency it would not be an easy task to find suitable dispatch routes, or the nearest hospital or service provider. gis interoperability can certainly help with each of these aspects. in addition to those examples, the city of toronto has used gis interoperability for a variety of evacuation plans including nuclear planning exercises. the city of vancouver is located in southwestern british columbia, canada and is part of the greater vancouver regional district (gvrd), otherwise called the lower mainland. the emergency management department is the city of vancouver's agency that deals with emergency mapping. gis applications for emergency management at the city of vancouver are over years old. this makes gis applications for disaster management at the city of vancouver very mature. both desktop and internet gis in addition to mobile gis are used on a regular basis for processing and coordinating disaster management activities in the field. the emergency management department at the city of vancouver is administered by about technical gis staff members. it operates the emergency operation centre (eoc), which is a command control center wherein all disaster management stakeholders (city of vancouver, province bc, psepc, and rcmp) meet during emergency situations. eoc is a sophisticated emergency center which provides complete emergency management services, including gis modeling and visualization. the city of vancouver relies mainly on desktop gis for data processing, but also on mobile gis, which is used for field data collection. the city of vancouver has expressed a keen interest in gis interoperability for disaster management coordination. the aim of the gis technology development plan for the city of vancouver is to create a gis database that is as complete as possible and one that can be updated daily or even more frequently if necessary. additionally, the important role of web-gis in the day-to-day activities of the emergency management department has further justified the need for interoperable gis. this justification stems from a multi-stakeholder, multi-institution and multi-tier decision-making process. using the same levels of integration evident in the city of toronto; the city of vancouver is integrating its data sources with various governmental levels as well as with business (e.g., the city of vancouver also shares the city of toronto's vision that web-based gis applications will dominate in the future). there is a high level of coordination between the city of vancouver and its ngos that are represented in the city emergency operations centre (eoc). this coordination, allow these organizations to have direct involvement in decision-making processes, as well as to facilitate their data and information access with the emergency operations center. the city of vancouver has extended its gis applications to address the social implications of disasters. the city of vancouver coordinates gis data delivery in an interoperating manner locally between engineering, police and fire departments, as well as with other governmental agencies. field data collection using mobile gis devices is the most advanced application in vancouver. in terms of challenges, the city of vancouver eoc has provided the city's gis expertise to various decision-making levels involved in disaster and emergency management. this might be justified by the fact that vancouver is considered to be more vulnerable than toronto, due to vancouver's location in a seismically active zone and the city's proximity to the ocean. the city of vancouver has identified intergovernmental data sharing as an issue for achieving collaborative disaster management coordination. this is largely due to the difficulty of extracting important information from the system. the city of kitchener, in southwestern ontario, had a population of about , in (dept. of geography, university of western ontario ). kitchener is the location of the waterloo regional municipality and is adjacent to the smaller city of waterloo. the it department in this region is responsible for gis applications, including emergency management applications. both desktop and internet gis are used, with emphasis on desktop gis. waterloo region has utilized gis interoperability for emergency management for the first time in the preparation of the ontario emergency management act. in the process of complying with this act, environment canada has launched the atmospheric hazards website (www.hazards.ca.), which provides interoperable gis service for all municipalities. table is showing comparative analysis of data handling capabilities in the studied municipalities. as it is obvious from this table, larger municipalities, have better resources. dufferin county is located in south-central ontario, canada. orangeville, the county seat, is located approximately km north-west of toronto. it consists of three towns: mono, orangeville and shelburne; and five rural townships: amaranth, east garafraxa, east luther grand valley, melancthon, and mulmur. although the region is small, it has had an emergency management coordinator since . dufferin county is a typical small region with limited resources. emergency management activities in this region can be directly related and compared to large regions. dufferin county does not have a specialized gis officer to deal with emergency mapping issues. all gis work related to emergency management and other activities is managed by a public works drafts person. table shows a comparative operational analysis for the municipalities assessed in the study. this section demonstrates the optimal solution that gis interoperability might provide for enhancing emergency management operations. the designed demonstration scenario stems from the various problems with data and systems heterogeneity found when analyzing the utility of gis interoperability for emergency management in four local governments. it is important to mention that the main objective of this section is to demonstrate how gis interoperability can provide a solution for disaster management. hypothetically an emergency response can be simulated in order to show how gis interoperability functions in such a situation and what this could provide to emergency management decision-makers. in the present case, when the various flood scenarios under different flood levels have been simulated and the damages can be assessed, the results obtained can be published and visualized in a d web environment using geoservnet. a hypothetical flood scenario in the don valley was used to demonstrate the solution that gis interoperability can provide for emergency management. the don river is a system that flows through the greater toronto area (gta). the origin of the don river is in the oak ridges moraine where the headwaters are fed by numerous aquifers. the river then flows for km to lake ontario, providing drainage for square km of land. the section used for this study is part of the don valley watershed system in the province of ontario, as shown in figure . dmti topographic digital maps in the form of shapefiles and dem were obtained from the york university map library (dmti ) . topographic sheets of the area were used as a reference for conducting this study. data describing flow statistics were simulated. based on the ontario emergency management doctrine (emo ), different ministries are responsible for dealing with different natural hazards. this section provides a generic overview of what the exact benefits are that each ministry can gain by utilizing gis interoperability. due to information privacy and security issues, it was not possible to simulate this model as part of a real exercise. however, the adopted techniques have closely mimicked the simulation exercise environment. the trca is responsible for flood simulation, floodplain mapping and water surface measurement. all hydraulics and hydrology data are under the custody of the trca. in such an event the trca will provide flood models and data through interoperable access to all decision-makers involved. products like the flood plain map shown in figure can be simulated and made available to all actors involved. real and semi-real time situational awareness models can be generated and accessed on demand based on stakeholder needs. access to tabular and text information is also possible. city of toronto emergency services is responsible for providing services in a variety of situations, ranging from simple road maintenance closures to extreme disaster situations. the city produces and hosts its own data, and aims to make data standardized and interoperable with other parties. the city of toronto can provide data about land use categories affected as a result of the flood and about what kind of infrastructure sectors can be impacted by the flood, as shown in figure . the city can also pro-vide real-time field information by utilizing interoperable mobile devices for data collection and transmission. the toronto police service is responsible for maintaining law and order in the city. in emergency situations the city police department can utilize gis interoperability in a very efficient way. this includes accessing flood data provided by the city's emergency mapping department and that provided by the toronto region conservation authority (trca), pinpointing areas that are most vulnerable to traffic problems. based on this information they can deploy officers to organize traffic in that region. another example of how gis interoperability can be utilized is that police can transmit real-time field data of traffic problems, or any related security problems, on the fly for all stakeholders involved in a particular emergency management scenario. in emergency situations the city fire department can play role similar to that of the city police, however, in addition the fire department can assist with evacuation operations for particular locations in the city. also the fire department can access data and information provided by the city and the trca to identify the most vulnerable areas and to concentrate its efforts there. toronto ems can utilize gis data and information for predicting areas at high risk of experiencing an emergency and for planning how they can dispatch their services to these areas. another important utility of gis in-teroperability for ems is that, in emergency situations, it is not easy to prioritize your response to calls from different parts of the city. knowing where a call is coming from relative to the emergency is invaluable to prioritizing response. a key role for the emo is to monitor emergency situations, and to not get involved unless it is required. towards this end, gis interoperability could provide emo with improved situational awareness models by assembling data from all different departments and to make these available for basic analysis and visualization as shown in figure . the legend on the clip was captured from the web-based program. it is interactive and can be shown by either activating the legend feature or by pointing to the particular item in the map. gis interoperability can provide enormous benefits to the disaster and emergency management community. it is clear from the analysis of the questionnaire that the level and capability of gis interoperability for emergency management is not very well established or utilized at the municipal level, in particular in the small municipalities studied. networkcentric computing is necessary for processing large volumes of data and is achieved through the sharing of the computing power of other systems within the network. a limitation of a non-interoperable environment is that users from different decision-making levels are not able to access the same information at the same time. in such a case it is not a simple task to secure simultaneous data access and processing. this makes the elimination of system and data heterogeneity potentially very useful for disaster management applications. such applications make gis interoperability a highly demanding mechanism for disaster management coordination. gis interoperability is very useful in disaster and emergency management. disaster and emergency management stakeholders can benefit from gis interoperability by gaining access to standard, fast, accessible, shared gis for achieving efficient decision-making processes. this section will highlight some key implementation benefits that the emergency management community can gain by leveraging gis interoperability. establishing advanced interoperable applications and services is a key future aim of gis and technology development plans at the city of to-ronto. a second aim is that of providing the required geomatics services to support city of toronto emergency management detection, prevention, planning, response, and recovery challenges. the city of vancouver is working on improving and extending the current level of interoperability in order to improve the efficacy of their disaster management coordination. it is also working to improve networkcentric gis computing through a three year evaluation and upgrading plan. furthermore, the city is considering to extend their visualization and analysis applications to include d gis. the city of vancouver is also looking for university contribution in the area of data management and sharing. emergency service must aim to be timely and accurate, whereby geospatial information and geoprocessing services are easily accessible and capable of being shared across jurisdictions and multiple security levels. also, the city plans go further to advance gis interoperability and capabilities through the hosting of a web map service (wms/wfs) site. the city of toronto gis emergency mapping department is also aiming to get assistance from universities for gis development for disaster management applications with regards to standards and specifications development. the city of toronto is intending to use web-based gis for disaster management and emergency response projects for operational plans and in the event of an emergency, this constitutes a geomatics-centric incidence response. the specific benefits resulting from gis interoperability are summarized in the following several sections. gis interoperability allows for open access to multiple data sources. this benefit helps decision-makers to access multiple servers, thereby obtaining data and services that do not necessarily occur in the same location or even within the same organizational boundary for that matter. through gis interoperability, the emergency management community can move towards one or several closely related standard data formats that can be used in data transfer and information sharing. standards-based gis interoperability helps to provide a simple and accessible means of integration to decision-makers. this is crucial since emergency management operations stand to benefit considerably from a process that allows for timely gathering, modeling and analysis of information. if the system is not simple and accessible it will not be easily implemented during disaster management and emergency response. gis interoperability, through its standardized protocols has allowed gis users to utilize a simple and standard service. within the context of interoperability, transparency refers to the process of accessing and sharing data between systems without the use of complicated, cumbersome protocols. this differs from the concept of 'common format' in that a common format is not necessarily easy to use. through a transparent system, emergency management stakeholders can readily access gis data and systems that are external to their system domain. gis interoperability can be expanded or contracted by adding or eliminating nodes. this flexibility in scalability in systems and services is useful in emergency management operations, which, due to their dynamic, fast-paced nature, require that previously unexpected situations be accommodated. to date, considerable effort has been expended toward providing efficient, interoperable solutions for disaster and emergency management. however, gis interoperability remains a stimulating field and research is still underway into addressing many aspects of interoperability. the following subsections address specific problems and challenges that remain in this field. from an operational perspective, there are particular issues related to the degree to which data conversion hinders efficient data interoperability. this may arise if, for example, a particular department is using engineering data that is stored in a computer aided design (cad) format and another department is using data stored in arcgis shapefile formats. these two formats can be made to be compatible by converting cad data into the shapefile format. the time required for this process depends on data size and system capabilities. different processes and techniques are used by different departments. this can create an obstacle to achieving gis interoperability. a streamlined process and system capabilities are required for effective gis interoperability. different departments have specialized staff expertise and technical capabilities, this makes it a difficult and delaying process to comply with gis interoperability requirements. another issue is related to bandwidth load. this is very important in securing efficient network performance without overloading a particular network. data maintenance and update is another issue that represents an obstacle to achieving gis interoperability. where there is no clear policy that identifies roles and responsibilities for each node in an interoperable system, data update, maintenance and management can be a challenge. access rights to sensitive information, such as infrastructure and emergency management, represent another issue. much disaster management data and information are, for a variety of reasons, not meant for public access and as a result are categorized as 'classified.' what are the criteria that should be used to categorize data and information to a specific clearance level? this is a key question and challenge that can represent a serious obstacle to gis interoperability. another crucial issue is related to corporate technology procurement policies, which can contribute to delayed implementation. it is evident from the study that the city of toronto produces and owns its own data while at the same time using data from other neighboring regions. the level of data sharing in this form doesn't constitute 'interoperability'. however, this could be enhanced by using data exchange standards to make these data useable not only to toronto and neighboring regions, but to any other institution involved in emergency management operations. the same benefit could be gained by the city of vancouver, which utilizes its locally produced data along with other non-proprietary data. waterloo and dufferin regions utilize external data sets, indicating a clear need for data standards and gis interoperability, since both regions use the same web-service and have different problems that could be eliminated through proper gis data sharing. the region of waterloo has indicated that, when utilizing the environment canada web service, that they had experienced problems related to the level of detail and to layer matching. this indicates heterogeneity that could have been avoided through the use of a standard data model and format. the dufferin region emergency manager faced a problem when dealing with the online web gis service, finding it to be too technical in nature. in contrast, large cities like toronto and vancouver have specialized technical departments that are capable of dealing with technical gis issues. gis interoperability can help in eliminating the detailed technical expertise required to utilize desk-top gis packages and can provide a considerable additional benefit that it can be leveraged over the internet for many users simultaneously. as the case with the city of toronto indicated, large cities produce, utilize and share data with other users. however, this is performed through procedural data exchange not through a systematic, dynamic process. gis interoperability achieves this capacity in that it can allow for decentralized data handling and access from different servers. waterloo and dufferin counties are able to access and visualize data from an interoperable web service, which provides them with access to data that they do not own. this level of gis interoperability helps to provide an efficient solution to the challenge of timely access to emergency management data. at the same time it reduces duplication of data sets in more than one site, thereby saving storage resources. this paper has shown that gis interoperability is effective at coordinating the emergency management decision-making process by allowing simultaneous data and information access and updates. two scenarios have outlined how network-centric gis can best be used in modeling and visualization of disaster management scenarios. through its integration with other modeling systems, gis functionality provides decision-makers with tools that can improve the decision-making process. in this sense, a virtual emergency management center can provide near real-time data access to decision-makers in different locations. one of the limitations of this study is that it has only two integrated earthquake shakemap models and hydraulic simulation models as input into a gis database. other models that provide detailed information about cascading effects, escalating failures and systems dynamics could also be included as input into gis databases and would provide very advanced visualization capabilities. utilizing other spatially enabled modeling components would significantly help with expanding our understanding of the complex issue surrounding critical infrastructure interdependencies. the temporal dimension is very important in quantifying and understanding damage magnitude, peak flood spatial extent and the impact on each of the interdependencies between various infrastructure sectors and systems. in this dissertation, the temporal aspects of disaster management scenarios have been discussed, and only the peak flood extent has been used in building the knowledgebase. explicit study of the temporal aspects associated with disaster management would be of great benefit to the disaster management community. qualitative causal modeling in temporal gis overcoming the semantic and other barriers to gis interoperability the role of gis: coping with space (and time) in air pollution exposure assessment temporal gis: advanced field-based applications spatio-temporal dynamics in california's central valley: empirical links to urban theory an integrated approach for flood risk assessment for the red river in southern manitoba, annual conference of the canadian society for civil engineering mobile geographic information handling technologies to support disaster management disaster management scenarios, univ. of arkansas, ogc discussion paper gis technologies for data collection, management and visualization of large slope instabilities: two applications in the western italian alps the need for open gis -part : the integration challenge. mapping awareness geographic information science and systems for environmental management environmental modeling with gis disaster management for nandira watershed district angul (orissa) india, using temporal remote sensing data and gis a framework for temporal geographic information geographic information systems and science a spatio-temporal gis database for monitoring alpine glacier change. photogrammetric engineering and remote sensing opengis reference model making space for time: issues in space-time data representation representation of space and time a spatio-temporal model for the manipulation of lineage metadata automation and cartography gis -enabling technologies, th agile conference on geographic information science geographic information-systems -the case of disaster management key: cord- -vs famsa authors: foley, m.; mcpherson, g.; mcgillivray, d. title: establishing singapore as the events and entertainment capital of asia: strategic brand diversification date: - - journal: international perspectives of festivals and events doi: . /b - - - - . - sha: doc_id: cord_uid: vs famsa nan contained within singapore tourism board's (stb) vision for tourism is the stated intention to establish singapore as the ' events and entertainment capital of asia ' . this strategy is part of wider economic development agency attempts to diversify singapore's brand beyond its well established reputation as a leading business destination. the city wants to capture the attention of global tourism markets by redefining itself as a vibrant cultural hub with an events and entertainment offering to rival some of the world's most attractive cities. this strategy can be viewed as a response to the intensification of global place wars for attention which have increased the pressure on destinations the world over to create unique attractions to entice valuable mobile capital. this chapter provides a critical overview of the global context for inter-urban place wars before focusing on the value of an events-led strategy in delivering competitive advantage for singapore. methodologically, it draws on elite interviews with leading singaporean cultural policy makers, observations at local, national and international events and documentary analysis of the recent strategic environment for singapore tourism. we contend that the city branding and place-making strategies employed by the singaporean state apparatus are designed to create cultural strategies which ensure the gentrification of space and place necessary for the reception of global tourism inflows. in essence, we suggest that singapore has used its events-led strategies to extend its internal processes of cultural planning, regeneration and development at the same time as securing a global position in the increasingly competitive events (and place) bidding wars. events (or culture)-led strategies in establishing competitive advantage for cities within the global economy. hall ( ) , reflecting on the growth of sports mega-events, argues that neoliberal entrepreneurial growth strategies are now regularly played out by cities around the world. in zukin's ( ) words, culture is increasingly the ' business of cities ' , an ' instrument in the entrepreneurial strategies of local governments and business alliances ' (p. ) . in urban environments across europe, the americas and asia, public and private growth coalitions come together to utilise events and festivals as a means of gaining competitive advantage in increasingly aggressive place wars ( haider, ; short and kim, ; yeoh and chang, ) with other aspiring global cities. these place wars are driven by the need to create a favourable image to tourism, migration and business marketplaces. increasingly, sporting and other cultural festivals and events represent particularly attractive communication vehicles for cities as they interact with the globalised media complex and vie for the attention of policy makers, consumers and investors, alike. in the competition for attention ( goldhaber, ) , places seek out means of differentiation and distinction; unique qualities which can attract valuable mobile capital to advance their economic standing. the decision to engage in city event branding of this sort is almost always politically motivated, rather than cultural or even economic. today, cities are under pressure to be seen to be bidding for sporting mega-events or to create large scale festivals so that they maintain position in the rankings of top global cities (shoval, ) . however, exploiting the cultural cache of festivals and events is not the only (or even the most popular) means for cities to secure attention. richards and wilson ( ) suggest that branding the built urban environment with signature or iconic buildings and cultural quarters is perhaps the most frequently used means of altering perceptions of a locale. yet, regenerative strategies based on the transformation of the builtscape ( chang and huang, ) suffer from the threat of homogeneity and serial monotony ( harvey, ) which has afflicted other destinations. moreover, in the fastpaced global economy, an over-reliance on inflexible, physical spaces of regeneration can leave destinations vulnerable to changing architectural fashions and ambitious competitors. in contrast, events and festivals ' provide a means of adding flexibility to fixed structures, supplying a source of spectacle which adds to the image value of a landmark ' ( richards and wilson, , pp. - , or of a destination. events are an attractive proposition for policy makers because they animate objects, they enliven the physical environment and, in their uniquely media-friendly form, they transcend geographical boundaries. using chang and huang's ( ) terminology, the creation of ' eventscapes ' also allows places to produce new symbolic (often contrived) meanings, catering for ' new lifestyle needs ' (p. ) . for example, reflecting on the regeneration of the singapore river, they argue that a process of ' creative destruction ' has taken place whereby the neoliberal ideological policy of the city has transformed the environment into ' an image of leisure and entertainment at the waterfront, at the expense of landscapes of past economic and social ills ' (p. ). investing in, and creating, festivals and events is doubly attractive to semi-peripheral cities and states ( whitson and horne, ) as they can use these spectacles to establish themselves on the world map. these events can also give others the impression that a city has an achievement and entrepreneurial orientation, informing potential suitors (e.g. investors) that political leaders are enterprising ( whitson and horne, ) . festivals and events permit semi-peripheral, or regional powers, to showcase their offerings through the global media to a watching audience, influencing perceptions of place identity -both externally (to the possessors of circulating capital) and internally (to members of the host population). the strategies discussed thus far only bear fruit because cities now operate in a fluid symbolic realm, where image enhancement carries a value; where the hosting of unique events helps cities express their ' personalities ' and advertise their position on the global stage ( essex and chalkley, ) . sporting and cultural events also fit with the dominant logic of consumption, providing a ' point of identification ' ( richards and wilson, , p. ) for consumers in a crowded marketplace. in discussing place images and their relationship with events, richards and wilson argue that ' events have become a particular valuable form of cultural currency ' (p. ) creating a favourable impression of the city or nation as a destination worth visiting. the proliferation of cultural and sporting festivals can be associated with, and supports, similar trends towards a cosmopolitan ethic which defines a neighbourhood or city as vibrant. when contrived or manufactured events are hosted, the façade of the city is invariably dressed is such a way as to communicate specific impressions to target audiences. events are invariably located in gentrified spaces (or in places which are undergoing gentrification processes) and help choreograph forms of cultural consumption which fit with how the city wishes to be perceived, and with the values of those people it wishes to attract (principally the incoming visitor). the visual representation of cities is particularly valuable in the dominant symbolic realm of inter-urban place marketing competition. festivals and events provide city marketers with a plethora of suitable vibrant, colourful and multicultural images which are easily packaged for global circulation. sydney has its mardi gras, rio exploits the carnival and london uses notting hill carnival to represent the city in a suitably cosmopolitan way. the process often involves recreating a sanitised historical narrative ( chang and huang, ) , one that the governing agencies can utilise to secure the consent of the host population and which is also, crucially, exploitable as a tourism resource. internationally renowned festivals, such as notting hill carnival, were often created to address the threat posed by social unrest and riots and were targeted towards a particular ethnic minority group. today, however, these events are invariably used as a clever marketing tool for civic leaders to showcase their destinations ' cultural diversity. political decision makers in cities such as rio and new orleans have continually reinvented their festivals by globalising local celebrations and selling them as unique attractions via global media networks. behind many city event-led strategies sit entrepreneurial governments seeking to attract circulating capital ( schimmel, ) which brings the ' footloose consumption ' (short and kim, , p. ) of tourists and conventions to their destinations. in the s and early s, us downtowns were transformed into packaged landscapes ( boyer, ) with cultures of consumption being defined by spectacularised urban space ( hannigan, ; harvey, ) . this format for urban growth is now replicated across the world, with cultural consumption at its core. in developing major festival and events strategies, cities tend to work to a common denominator in respect of the markets being courted. these tend to be high spending tourists, middle-class professionals and potential investors. however, the beneficiaries of these event-led strategies are not always those people to whom the city leaders are democratically accountable. it is to the politics of event-led growth that we now turn. of course, in the competition for favourable city status there are invariably winners and losers. as hall ( ) contends, pursuing a major events strategy may well produce lucrative short term gains for private interests (e.g. construction firms, advertisers or sponsors), but this can bring more negative long term consequences for other public stakeholders. this view is supported by the work of smith ( ) , macleod ( ) and others who consider the changing urban policy landscape to be defined by a dominant neoliberal logic in central and local government towards urban entrepreneurialism subsidised by the public purse, which leaves some stakeholders disempowered from decisionmaking processes and from the promulgated economic rewards. as control over content and promotion is handed over to multinational conglomerates -the driving force for many large scale events -cities and nations also risk alienating the citizens who are identified as the main beneficiaries. once sponsors have a stake in an event, the presentation of place for target market consumption is more difficult to manage and control. hall ( ) identifies the problem as being about a perceived democratic deficit, whereby local citizens are disempowered from their rights in the furtherance of a large scale events policy. alongside whitson and horne ( ) , zukin ( ) and richards and wilson ( ) , hall ( ) asserts that the dominant discourse of capital accumulation provides an ' ideological justification for place-competitive re-imaging strategies ' (p. ), and a ' competitiveness hegemony ' (p. ), which places the logic of capital central to policy discussions and decisions. gray ( ) labels this the commodification of cultural policy, where decisions on investment in forms of cultural expression are made with economic logic in mind. in pursuing an events-led regeneration strategy as a means of escaping ' routine identities ' ( richards and wilson, , p. ) , cities also face the threat of reinforcing sameness and cultural uniformity, in creating a ' homogenised uniqueness ' . furthermore, in following a strategy of creating international (or global) events for touristic consumption, the sharp contrast between the host population and the affluent tourist tribes ( schimmel, ) being targeted by city governments may also be thrown into view. for example, judd ( ) , commenting on the fallout from an overemphasis on attracting tourist dollars in the united states, warns that the islands of affluence created often hide the real material deprivation and cultural exclusion faced by some host residents. cultural and sporting events have also been employed as a means of addressing the tensions associated with multiculturalism ( zukin, ) expressed in the promotion of ' local ' ethnic uniqueness (chang, ). yet, this again can be understood as an intentional policy response to the threat posed by global (read standardised) culture, using cultural diversity as an instrumental tool to attain non-cultural aims and objectives ( gray, ) . the symbolic realm ( zukin, ) -a realm of images, signs and spaces in cities -permits the creation of collective identity forms, albeit one frequently mediated by the relationship between ' cultural symbols and entrepreneurial capital ' ( zukin, , p. ) . in implementing an events-led strategy with the discourse of enterprise at its core, debate over the appropriate use of contested public space is also brought to the fore. the loss of public space free from the logic of consumption is an issue which has attracted the attention of academic commentators and anti-globalisation prophets in recent years (see klein, ; zukin, ) . they argue that civic spaces are now colonised by private capital (e.g. sponsors), often at the bequest of the public authorities. there are a number of problems associated with this development when considered in relation to festivals and events and their projected tourism returns. first, as invented or contrived cultural events and festivities colonise civic space (e.g. squares, main avenues) the outcome can be the production of intensely regulated, or gated, communities identified by the presence of security barriers, security guards and the ubiquity of cctv cameras. regulatory control over licences, traffic management, environmental pollution and the like ensure that the civic authorities and their (growth) coalition partners can easily manage the cultural offering to produce ' safe ' spaces for tourist consumption. however, this can leave the impression of a public culture controlled and contained, managed and directed for the benefit of the footloose consumer. the implications of what gray ( ) calls an acceptance of a commodified conception of public policy is that collective space is re-conceptualised as consumable space. in focusing on the singaporean context for events and festivals over the last decade, the empirical component of this chapter will now review critically the implications of the nation's drive towards the title of ' events and entertainment capital of asia ' . since gaining independence from the united kingdom in , the singaporean government's main aim has been to maintain stability in the areas of economic and environmental development. at the same time, the government has also continued with its drive to reinforce a discourse of national identity through the development of cultural policies based on the promotion of singapore's shared values. politically, whilst the city-state is a democracy, the people's action party (pap) has been the only ruling power since it took over the reigns from the colonial governor. singapore does have a representative democracy and has official united nations ' recognition as a parliamentary republic. despite being small in physical size, singapore has a high population density of approximately . million people which in the census encompassed a multi-ethnic mix of chinese . %, malay . %, indian . % and others . % ( www.singstat.com , ) . as a post-colonial power, singapore has invested heavily in creating a sense of national identity, often using the vehicle of cultural events as a means of integrating the diverse multi-ethnic population along the lines of shared singaporean values (e.g. national day celebrations). indeed, in singapore, the debate over the need for a strong sense of national identity started at independence from british colonial rule ( kong, ) . this movement strengthened in the s and s as part of a larger nation building initiative. the pap's authoritarian regime ( tamney, ) , at least in the first three decades of independent rule, promoted a discourse of national survival and the protection of asian values in the face of the challenge posed by perceived western decadence. however, as singapore rapidly industrialised, the focus of government policy shifted from ' protection ' and the cultivation of shared national values, to the promotion and encouragement of inward investment in entrepreneurial growth strategies. the success of this strategy is illustrated by singapore's position as the most economically successful country in south east asia ( ooi, ) . singapore's rapid industrialisation in the s and s was based on the authoritarian regimes ' tight regulation and exploitation of shared national values of hard work and nation before community. however, as strong economic returns were amassed, the attention of government and citizens alike turned from necessity to luxury; from work to leisure and consumption. through the s and into the new millennium, the government has had to re-evaluate its authoritarian approach as its working population reflect upon the sacrifices made in the name of economic growth. in policy terms the government has created heritage spaces and other ' places to play ' (judd, ) whilst, at the same time, maintaining a ' hegemonic ' control over their population. however, in recent years, singapore has also sought to exploit its popularity as a travel destination, even in the face of the sars (severe acute respiratory syndrome) crisis early in the new millennium. despite this crisis, tourism has evolved into one of its largest industries, with around . million tourist visits in . the singaporean government has set a target of at least million visitor arrivals by . the orchard road district is the central retail hub in singapore but, until recently, the city has suffered from a relatively low attractions base. however, this has been addressed by the tourism authorities and the urban redevelopment authority over the past few years. these agencies have been involved in the development of two integrated resorts at marina south and sentosa island, alongside the singapore flyer, the gardens by the bay, the singapore river development and the construction of the double helix bridge connecting tourist attractions in and around the packaged landscape of marina bay. whilst the ' builtscapes ' ( chang and huang, ) have been markedly enhanced, this has gone hand-in-hand with the development of the accompanying ' eventscapes ' ( chang and huang, ) . the great singapore sales, singapore food festival, the singapore river hong bao festival, the singapore arts festival and the chingay parade represent opportunities to promote singapore to regional and international markets. add to this sporting events, like the singapore masters, the singapore marathon and the f grand prix (due to visit singapore in for the first time) , and it is clear that singapore is following a well-trodden path towards the use of events and other cultural forms as valuable commodities worth packaging and selling to the rest of asia and, increasingly, to wider tourism markets. in many respects, singapore has invested in its creative and cultural offering as much out of necessity as of choice. this need is driven by the fact that there are scant natural resources in this island nation, due to its small land mass and high population density. unlike korea and taiwan, singapore does not have ship building or agricultural activities on which to generate economic growth. however, the ruling party seized the opportunity to use ' cultural maintenance ' to both exercise power over the people and form new markets ( miller and yudice, ) . from the late s onwards, the singaporean state, through its vehicles of economic development (the ministry of trade and industry and the singaporean tourism board), has pursued an ambitious strategy to attract global tourism spend by re-branding singapore as more than a business travel destination. in recent campaigns, singapore has been labelled a ' global arts city ' , ' uniquely singapore ' , an ' eventful city ' and, most recently, the ' events and entertainment capital of asia ' . it is the final label, the events and entertainment capital of asia that will occupy our attention in the remainder of this chapter. in the furtherance of this study on the event and festival strategies being utilised in the promotion of singapore as a tourist destination, a mixed methods case study approach was employed as it ' allows an investigation to retain the holistic and meaningful characteristics of real-life events ' ( yin, , p. ). yin ( ) argues that the benefit of employing a case study approach in the contextual situation of the studied phenomena is integrated into the mode of enquiry, thereby permitting the relationship between context and phenomena to be delineated. the research strategy underpinning this chapter took two main forms. the substantive phase of fieldwork was gathered by members of the research team during a field trip to singapore in february . elite semi-structured interviews were conducted with representatives from statutory and non-statutory bodies drawn from the tourist sector, from cultural institutions and from enterprise organisations. interviews were held with individuals from the national arts council ( ), national heritage board ( ), singapore tourism board ( ), singapore sports council ( ) and the international festival and events association ( ). the research team intentionally selected interviewees who were in a position to make meaningful comment on strategic issues pertaining to events and festival policy in singapore, whether in the arts or in sport. each interviewee was asked questions around key themes concerning the rationale for investment in festivals and events and the policy outcomes sought. themes included: • the perception of events and festivities in the tourism product of singapore now and in the future. • the strategy to make singapore the events and entertainment capital of asia. • the sensitivity of multi-racial diversity issues in promoting events and festivals to tourist audiences. • placing singapore on a global map and the importance of local cultural heritage in that positioning. • the role of sports and arts events in making singapore into a global player for the events sector. • the marketing of singapore as the bridge between the east and the west for international events. • the role of local events in forming singaporean cultural identity and the promotion of this globally. given the three-year time lag since the completion of the elite interviews, an extensive desk-based research phase was also undertaken in to provide an update on the singaporean context and to investigate the policy rationale behind a significant intensification in singapore's pursuit of an eventsled strategy since . documentary analysis was carried out on a number of strategy documents pertaining to economic and tourism policy and on press coverage relating to several of singapore's renowned cultural and sporting events. the documentary analysis eschewed content analysis techniques in favour of discourse analysis. the former is a quantitative and scientific approach which focuses on the ' direct, deterministic and unilinear link ' within documents, ' from sender to communication to recipient ' ( jupp and norris, , p. ) . however, in evaluating the contents of government policy and strategy, it is more meaningful to consider the status of ' official ' documents as socially constructed entities. that withstanding, documents are subject to multiple interpretations both temporally and spatially. for this chapter, a more qualitative, discourse analysis of strategy and policy documents was undertaken, taking into consideration the distinctive political and economic context of singapore at the time of their publication. when considered alongside the views of the elite interviewees -the ' local interactional context ' ( flick, , p. ) -a more thorough evaluation of strategic rhetoric and local realities can be accessed. leisure and tourism markets represent key strands in stb's strategy to create a unique destination singapore brand identity that complements its well established reputation as a leading business destination. the stb has a professed aspiration to establish singapore as the ' events and entertainment capital of asia ' (stb, ) , attracting ' a big variety of the world's best events year round for visitors to enjoy ' . working in tandem with the principal economic development agency, the ministry for trade and industry (mita), the stb provides public subsidy and expert support to incentivise cultural and sporting festivals and events to attract tourist expenditure. this approach is in line with the city's long term goal of competing on a global level, and in presenting itself as safe asia ( foley et al., ) offering sanitised, hyper asian experiences alongside dominant western ideologies of consumption. events and festivals have become a key plank of the city's global strategy to communicate, or present, an alternative singaporean identity to the rest of the world. chang and huang ( ) suggest that the singaporean authorities are pursuing a strategy of ' forgetting to remember ' , a ' strategic undertaking that streamlines the past in ways that are coherent to the present and profitable for the future ' (p. ). chang and yeoh ( ) also suggest that singapore's cultural landscapes are repackaged as marketable commodities. in the case of singapore's events-led strategy, the ' profitable future ' is build around increasing tourism spend and in creating favourable impressions of singapore as a distinctive destination to visit -a destination which is progressive and sophisticated, yet still an expression of the asian soul (e.g. the new asia marketing campaign). that it is a strategic undertaking that is evidenced in the level of g overnment support which some showcase events receive, whether that be in the arts and cultural area or in relation to large sports events. in many cities government support is forthcoming because of the projected international tourism returns accruable from events, but in recent years singapore has deliberately altered its strategy to limit the number of events it invests in. as the singapore director of the international festivals and events association (ifea) acknowledges: our strategy is now to improve on developing quality in world class activities that have got tourism appeal (wong, february , interview) . in developing events with tourism appeal, the place marketers encourage the promotion of activities which ooi ( ) argues falsify time and place; events without a past but with an exploitable future. these events overlook some elements of the rich cultural heritage of the city, in favour of marketable commodities. the promotion of what chang and yeoh ( ) call inauthentic products is apparent in singapore's recent successful attempt to attract one of the world's most lucrative transportable sporting events the f grand prix to its streets in . this event promises to be the first ever night race, designed specifically to exploit television audiences in asia, europe and the united states. the singapore government expects tourism revenues of £ million from the event (mti, ) ; however, the direct economic benefits are only a small part of the overall strategic rationale for hosting the event in singapore's recently redeveloped marina area. the principal strategic driver is to re-position singapore as a leisure and tourism destination in the minds of existing and new markets. in the intensely competitive asian region, singapore is adopting a strategy of urban entrepreneurialism, competitiveness and growth ( hall, ) . driven by its agencies of economic development, the singaporean state has engaged in a place-competitive re-imaging strategy intended to produce a ' vibrant global city that is abuzz with high quality entertainment and events ' (mita, ) . to further emphasise the strategic importance of this flagship event to the city, the stb has made a commitment to fund % of the costs from a tourism development fund, complementing private investments. this represents an example of public and private growth coalitions working in tandem to showcase an area's unique facilities and attractions, as a means of gaining valuable coverage in the global media complex. singapore's events-related investment is not, however, restricted to the realm of mediasport events. the arts and cultural field is also following what gray ( ) calls a commodified conception of public policy, the instrumental use of culture for non-cultural outcomes in its adoption of flagship arts events (e.g. singapore arts festival) to promote singapore to a watching global audience. as the director of programme development at the national arts council suggests: our mission is to develop singapore into a global arts city. so that's the way we are and so creating these events will help to put us on the world map … that sense of positioning ourselves and how we make strategic positioning of singapore … how we can use the arts to give singapore an identity and an image which i think reflects us (lee, february , interview) . much of the strategic rhetoric in singaporean policy is concerned with creating distinction within an increasingly competitive global marketplace, capitalising on a (constructed) shared heritage, unravelled cultural diversity and outstanding infrastructural hardware. as the director of special projects at the stb indicates: we would use events as a main hook, a main magnet -we have to differentiate ourselves … so what we look for as strategy for singapore is events. it is events which actually leaven what you call the bread. the bread could be baking with shopping, with a lot of lifestyle activities, but it is events which have a fantastic pulling power (khor, february , interview) . singapore is certainly using ' unique ' events to attract attention from key markets as a means of increasing its levels of tourist visitation towards its target of doubling visitor arrivals to million a year (tourism working group report, ) . the government's investment in attracting large scale regional and international sports events (e.g. singapore open golf, lexus cup golf, singapore masters golf, aviva singapore open badminton, singapore marathon) has recently been supported by the construction of the singapore sports hub, the ' hardware ' (wong, february , interview) , which is described as ' a unique cluster development of integrated world-class sports facilities within the city … it will play a critical role in accelerating the development of the sports industry ' (singapore sports council, ) . singapore clearly wishes to enhance its level of status and prestige, giving visitors a reason to identify with the city. as the stb chief executive, lim neo chian, illustrates with respect to the grand prix, singapore wants to position itself as a place to ' be in and be seen in ' (stb press release, ) . this further reinforces richards and wilson's ( ) view of the cultural currency of events in creating a favourable impression of the city or nation as a desirable destination. in referring to the importance of the chingay festival in promoting singapore to external markets, the director of ifea emphasises the: marketing value of this event being broadcast in portugal, for example, and the eyeballs that see singapore as a happening and aspirational place -it is imprinted on this individual's mind -one day i would like to go to singapore (wong, february , interview) . using hallmark or special events to manage impressions of a destination can further enhance the existing product offering, whether cultural, sporting or business. returning to the singapore grand prix, the stb believes that its presence in singapore will create ' positive energy ' , unrivalled ' exposure ' and an opportunity to showcase the city's physical, cultural, sporting, artistic and historical landmarks. events provide an unparalleled immediacy of message which makes them attractive to place marketers: branding brings in immediate returns in terms of media attention, global media attention. so we are very conscious of the branding potential of ourselves as an eventful city. but now we are going to be more strategic and discriminating in picking up the ones (events) that will attract different markets (khor, february , interview) . what is apparent in this strategy is that the government agencies are now discriminating between those events which have local value and meaning and those which will bring exposure to new audiences and lucrative broadcasting revenues. at this time, the agencies responsible for economic development are concentrating on exploiting the potential of the latter, sometimes at the expense of events with significant national (and regional) appeal: you have … events like table tennis and badminton which we are actually quite good at, in asian culture we are quite good at. we have opportunities to win gold medals at olympics or asian games, but from the commercial infrastructure perspectives it is limited because the sports are not really sexy -there isn't enough appeal (khoo, february , interview) . in this example, decisions over the support for specific sports events are made on the basis of commercial appeal and not national participation targets. this reflects the dominance of neoliberal entrepreneurial strategies and their impact on other public stakeholders within the singaporean context. the singapore sports council interviewee (khoo, february, interview) indicated a tension between the needs of the sports development agenda and the economic imperatives underpinning the international events strategy. the logic of capital certainly informs sport and arts policy in singapore, but with low levels of expressed discontent a feature of singaporean society, the outcomes of the policy drive are perhaps less noticeable than in other cities (e.g. toronto). another noticeable feature of singapore's event-led strategy is the way in which the promotion of indigenous cultural events (e.g. chingay, river hong bao festival and taipusam festival) comes together with world-class sporting spectaculars to symbolise the notion of a ' new asia ' brand, where ' east meets west, asian heritage blends with modernity and sophistication, and old world charm combined with new world vision ' (mita, ) . chang and huang ( ) argue that the creation of the new asia brand in singapore is tied up with re-fashioning the built environment (e.g. the river), the staging of events and activities (e.g. the f grand prix) and the establishment of public art installations. they also see this move as reflecting wider state attempts to create new memories and identities for singaporememories befitting its aspiration to acquire and sustain global city status through destination singapore. returning to mita's version of the new asia brand, the f grand prix epitomises the ' west ' , ' modernity ' and the ' new world vision ' . the street circuit is designed specifically to open up key landmarks to media view, animating the city's wider cultural heritage attractions to the watching world. in the singapore context, like elsewhere, events operate as brand vehicles employed to communicate visual and audio messages via the symbolic realm of inter-urban place marketing competition. however, despite singapore's apparent success in attracting the attention of the world's arts and sporting glitterati in the form of the singapore arts festival and the f grand prix, there are clear dangers associated with a rapid rise to prominence. given the earlier discussion of the dangers of serial monotony and homogenised uniqueness, it is important to subject singapore's events-led strategy to further critical scrutiny on the basis of its ongoing sustainability. in interviews with key policy makers, it was apparent that there is some concern associated with a shift away from a mainly local or regional events policy, driven by the demands of national unity towards a more abstract, place branding strategy. chang and yeoh ( ) warn of the creation of inauthenticity and the sports council representative reinforces this view in the following commentary: i think the first priority is to understand that events must be local first before you go outside. if you have a , seater and you can only fill it with , people even though it has got massive international appeal you are really losing out because international appeal takes time to build. i think for singapore, six to eight major events probably is just right for us and you can underpin that with a whole group of different events that can bring the vibrancy of a community (khoo, february , interview). this response was also repeated in interviews with the cultural agencies and with representatives of the stb. however, whilst the global place wars continue apace, it is unlikely that singapore's agents of economic development will alter their internationalisation strategies in the face of the inevitable global forces which require cities around the world to engage in interdependent transnational relationships with other aspiring contenders. singapore is often described as a ' hub ' for a variety of business and travel processes, but it is now striving to exploit its events and entertainment offering to gain recognition as a tourism destination in its own right rather than as a stopover on the journey to australia. since gaining independence from the united kingdom in , the singaporean government has undertaken a series of national unity projects designed to secure the active consent of its population around the values of hard work and thrift. however, with its rapid industrial and subsequent postindustrial growth, singapore has had to embrace the challenge of securing the valuable mobile capital of investors and tourists in the face of increasingly competitive global place wars. since the turn of the new millennium, singapore has invested heavily in an events-led strategy designed to secure its position as the events and entertainment capital of asia. in its use of sporting and cultural events to re-brand itself as a vibrant destination, singapore has sought to animate its existing attractions and landscapes to communicate positive cosmopolitan credentials to regional and international audiences. as part of this strategy, singapore has invested significant public funds to support infrastructural developments and bids for internationally recognised sporting events which bring immediate symbolic returns, in terms of the communication of managed images through the global media complex. the forthcoming singapore f grand prix is the vehicle on which singapore hopes to build an international reputation as a leisure and entertainment hub -one worth visiting as a destination in its own right. the brand identity transmitted in the interface between traditional cultural events and manufactured sporting spectacles is inseparable from the notion of singapore as new asia -a city in which tradition and modernity sit as one alongside multi-ethnic diversity and globally recognisable products and services. the old and the new, the authentic and the contrived are immutable features of the singaporean events offering. however, should the balance of power shift too far towards a reliance on disconnected and deterritorialised media events, then singapore may be relying on an aspirational event and entertainment capital of asia brand built more on the pursuance of symbolic identity than on material logic. cities for sale: merchandising history at south street seaport local uniqueness in the global village: heritage tourism in singapore recreating place, replacing memory: creative destruction at the singapore river new asia -singapore ' : communicating local cultures through global tourism olympic games: catalyst of urban change cultural identity and festivity: generating singapore through citizenship and enterprise in events activity commodification and instrumentality in cultural policy place wars: new realities of the s urban entrepreneurship, corporate interests, and sports mega-events: the thin policies of competitiveness within the hard outcomes of neo-liberalism fantasy city: pleasure and profit in the postmodern metropolis from managerialism to entrepreneurialism: the transformation in urban governance in late capitalism constructing the tourist bubble traditions in documentary analysis the invention of heritage: popular music in singapore from urban entrepreneurialism to a ' revanchist city ' ? on the spatial injustices of glasgow's renaissance cultural policy investing in singapore's cultural capital. ministry for information and the arts cultural tourism and tourism cultures the impact of cultural events on city image: rotterdam, cultural capital of europe deep play: sports mega events and urban social conditions in the usa globalization and the city a new phase in the competition for the olympic gold: the london and new york bids for the games singapore tourism web site three consortiums short-listed for singapore sports hub project new globalism, new urbanism: gentrification as global urban strategy the struggle over singapore's soul underestimated costs and overestimated benefits? comparing the outcomes of sports mega-events in canada and japan globalising singapore: debating transnational flows in the city case study research: design and methods key: cord- -drjfwcdg authors: shephard, roy j. title: building the infrastructure and regulations needed for public health and fitness date: - - journal: a history of health & fitness: implications for policy today doi: . / - - - - _ sha: doc_id: cord_uid: drjfwcdg . to recognize the importance to the maintenance of good health of adequate public health regulations and an infrastructure that provides clean water and appropriate waste management. . to see the lack of such amenities over many centuries, but the progressive development of public health bureaucracies dedicated to provision of an appropriate infrastructure for healthy cities, beginning during the victorian era. . to observe how responsibility for the provision of adequate housing for poorer city dwellers has been shared between government, benevolent entrepreneurs and charities. . to note the new challenges to public health presented by such current issues as the abuse of tobacco and mood-altering drugs, continuing toxic auto-emissions, the epidemic of hiv/aids, a decreased acceptance of mmr vaccinations, and the ready spread of infectious diseases by air travel. opportunities for the spread of communicable diseases have increased with the growth in size of cities. the success of urban living has depended in great part on governmental ability to maintain population health through the building of an adequate infrastructure to provide clean water and to dispose of waste, as well as the enactment of appropriate regulations to control the prevent the spread of infectious diseases. in this chapter, we will look at success in meeting these objectives in various communities from early history through the classical era, the arab world, mediaeval europe, the renaissance, and the enlightenment to the victorian era, concluding with some comments on current challenges to public health. in the hey-day of the persian empire, heat, cold, dirt, stench, old age and anxiety were all thought to contribute to ill-health. cyrus the great ( - bce) thus taught his soldiers not to urinate or spit into running water. dead matter was also carefully removed from water-courses, and the clothing of dead people was systematically burnt. during the mediaeval era, interest in public health was much more advanced in the islamic world than in northern and western europe. ali ibn-rabban ( - ce), a well-respected physician living on the south coast of the caspian sea, wrote in his seven-part medical work paradise of wisdom that: "no one should live in any country which does not have four things: a just government, useful medicaments, flowing water and an educated physician." in the eleventh century, the arabic biographer al-mussawir emphasized that the main duty of a monarch was the preservation of health and well-being in his subjects. thus, islamic legislation required physicians to pay regular visits to army units, prisons and people living in outlying areas. the practice of medicine was regulated through a religious office, the hisba, headed by an official called the muhtasib with some of the powers of a modern ombudsperson. one function of the muhtasib was to act as the city medical officer of health. he prevented people with elephantiasis from using the public baths, regulated the cleanliness of public places such as markets, and ensured that garbage collectors did not handle food. one interesting example of applied hygiene was the method used to determine an appropriate location for construction of the main hospital in baghdad (chap. ). the merits of various sites were compared by hanging up pieces of meat, and noting the location where decomposition proceeded the most slowly. the city of córdoba under moorish rule further illustrates the infrastructure typical of the arab world during the tenth century ce. among other facilities, the city boasted public baths. in northern and western europe, public health infra-structure such as aqueducts and sewers fell into disrepair following departure of the roman garrisons, and during the mediaeval era the sanitary conditions in most cities were appalling. positive developments were the development of quarantine procedures and the re-emergence of a few public baths. food inspectors were appointed, and some cities also introduced zoning regulations, requiring malodorous trades such as tanning to be undertaken outside the city walls. water supply and sewage disposal untreated waste was thrown directly into the rivers of london and paris, and travellers were advised: "wise men go over bridges, and fools go under them." in ce, king edward iii ordered the mayor of london to: "cause the human faeces and other filth lying in the streets and lanes in the city top be removed with all speed to places far distant, so that no greater cause of mortality may arise…" a fourteenth century ordinance prohibiting the emptying of latrines into a creek near london's city wall remained largely ignored, so that in the fifteenth century the stream was buried underground. substantial populations of hogs and cattle roamed the streets of many large cities, adding to the urban stench. uncontaminated water was a rarity, and a lack of refuse disposal encouraged rat infestations. infrequent bathing and unwashed woolen clothing led to a proliferation of fleas and other insect vectors of infection. during the mid-fourteenth century, two thirds of the european population was killed by the flea-borne bubonic plague (the "black death", - ce). many doctors deserted their patients during this epidemic, and others proposed preposterous remedies. guy de chauliac wrote: "so contagious was the disease…. that no one could see or approach the patient without taking the disease…for self-preservation, there was nothing better than to flee the region… to purge oneself with pills of aloes, to diminish the blood by phlebotomy and to purify the air by fire and to comfort the heart with senna and things of good odor and to soothe the humours with armenian bole and resist putrefaction by means of acid things." chauliac unwittingly kept the rats and fleas away from pope clement vi, by surrounding his bedside with charcoal burners. a few years following the black death, observant physicians hypothesized that ships arriving from overseas were contributing to the recurring epidemics of plague. at first, hostels for sick townsfolk and newly arrived visitors were set up outside the city, but this was not entirely effective in containing infection. thus in ce, a trentino ( days) of isolation on an uninhabited island was required at many european ports of entry. subsequently, the isolation period was extended to days, perhaps because of an ancient greek doctrine that a contagious disease became manifest within days. in britain, recently arriving travellers were quarantined on guardships, anchored in the thames estuary ( fig. . ). most of the roman baths in northern europe had been abandoned by the mediaeval era, in part because of the high cost of heating the bath water, and in part because the church considered public bathing as a common prelude to venal sins. the church also had concerns about reinforcing belief in the supposed healing powers of celtic water deities (chap. ). nevertheless, as prosperity increased in the latter part of the middle ages, public baths were built or reopened in various parts of europe. in britain, the king's bath was built over the sulis minerva temple in the city of bath, and paris had established public baths by the thirteenth century. in germany, the tradition of river bathing had persisted from celtic times, and a growing number of new public bath-houses were constructed during the th and th centuries. admission to a bath-house was expensive, and poorer germans considered the payment of "bath money" a great blessing. the full luxury package of a spa treatment included washing, scouring and slapping of the body with a sheaf of twigs, a steam bath, rubbing to induce perspiration, swatting the skin with wet rags, scratching, hair washing, cutting and combing, lavendering, and blood letting. unfortunately, some of the baths subsequently became the scene of debauchery, prostitution and infection, and by the sixteenth century, many were closed for fears of spreading syphilis, leprosy and plague ( fig. . ). personal hygiene substantial quantities of soap were traded during the mediaeval era, but this was used more for the washing of wool than for cleansing of the skin. monasteries boasted laundry rooms, and many women listed their trade as "laundry woman." however, the laundering of clothes was an infrequent luxury for poorer people, and indeed many had no spare set of clothing, so that fleas flourished in the poorer households. food inspection basic foodstuffs such as wine, beer, bread, meat, fish and salt were frequently adulterated in mediaeval times. to counter such abuses, several european governments appointed food inspectors. in britain, in , the assize of bread and ale regulated the price of these staples in relation to the price of corn. occasional renaissance scholars expressed some interest in health promotion. the english diplomat and scholar thomas elyot (c. - ) wrote a book entitle the "castell of health," summarizing the latest medical knowledge for those unfamiliar with greek, and the venetian nobleman luigi cornaro ( - ) wrote a book on the art of living a long life. santo santorio (chap. ) also sought to put hygiene on a mathematical basis. most of renaissance society showed little interest in public health or hygiene, as shown by the outbreak and management of the great plague. however, boards of public health were set up in some cities. two small advances in personal hygiene were the introduction of cotton clothing and a growing use of toothbrushes. diligent housewives adopted a few other simple changes in household management to preserve the health of their families, and cambridge university insisted on a direct control of its food supply, the great plague the london "plague" of ce was one in a series of european epidemics of bubonic plague dating back to the "black death." the great plague claimed at least , lives in central london, this being about a half of the population who had not fled from the city. indeed, the death count was probably underestimated, since publically appointed street monitors were open to bribery by those who did not wish to disclose that their house had become infected. samuel pepys commented that the prevalence of the disease was such that corpses could not removed during the hours of darkness ( fig. . ). people were confined to their homes if one family member was infected, thus virtually ensured the death of the entire household. two watchmen were posted at the doors of infected homes for days, at a cost of d per house per day, and the victims received a public stipend of d per day to pay for food, fuel and medicaments. believing that the disease was conveyed by miasmata, the college of physicians recommended using bonfires to displace the infected air. there was probably some incidental benefit from these fires, since the smoke tended to drive away the flea-ridden rats that were vectors of the disease. the epidemic was eventually checked by the great fire, which consumed both the rats and the plagueinfested slum dwellings. in europe, local boards of public health were established; they adopted various measures for the containment of epidemics and the provision of social support to the community. in some cases, they designated specific physicians to attend plague victims, and in florence, local doctors prepared a public information booklet that summarized current knowledge on plague prevention. a further responsibility of these boards was to deal with doctors who failed to report communicable diseases in wealthy patients. one roman doctor who was arrested for this offence was ordered to serve as resident physician at the local pest-house. outbreaks of the plague placed a severe financial stress upon some municipalities. in milan, extra funding was needed to hire physicians and grave-diggers, to pay for operating a quarantine "pest-house," and to reimburse the infected for two-thirds of the estimated value of their possessions, which were summarily burned. some municipalities set up immigration offices on mountain passes to control the arrival of infected travelers, and others restricted imports, exports, market trading, travel and funerals, although it was unclear how far these costly measures were successful in reducing the toll of disease and mortality. personal hygiene and household management one positive development during the renaissance was the introduction of washable cotton clothing and sheets. this greatly curtailed the spread of insect-borne diseases, particularly among those with sufficient wealth to own several changes of clothing. another innovation was popularization of the bristle toothbrush. this device had been invented by the chinese in the thirteenth century, but did not become popular in england until the late seventeenth century, beginning with the aristocracy. without necessarily knowing why, tudor housewives achieved some sterilization of their dairy equipment by scouring with salt and hot water, and then exposing utensils to bright sunlight. infestation of houses by fleas was also countered by sprinkling appropriate herbs beneath the rush mats that covered their floors. the renaissance saw further occasional attempts to control the quality of food, particularly for the wealthy. cambridge university insisted that the direct supervision of their refectories was important to preserving the health and well-being of their students. one of those promoting hygiene during the enlightenment was the physician james mackenzie, who in wrote a text on "the history of health and the art of preserving it." the enlightenment saw some improvement of health infra-structure many dwellings for the poorer citizens of europe.were now constructed of brick and boasted glass windows. and samuel johnson ( - ) was urging a pro-active response to the prevention of disease:"we must consider how many diseases proceed from our own laziness, intemperance or negligence… and beware of imputing to god, the consequences of luxury, riot and debauchery." the diderot encyclopédie, first published in , included a section on hygiene, which wss defined as: "the things which mankind uses or handles… and their influence on our constitution and organs." gottfried wilhelm leibniz ( - ) was perhaps the greatest enthusiast for public health during this era. he strove to establish a pattern of medical training that was oriented towards public health and preventive medicine rather than the treatment of disease. he reminded his colleagues that hippocrates had registered every successful cure, and he urged a similar meticulous recording of outcomes in order to provide a modern preventive medicine data-base. he proposed that standardized questionnaires should be developed to examine eating habits, and that careful mor-the enlightenment tality statistics should be collected so that findings could be correlated with the local climate, air conditions and the nature of the soil. a few other scientists such as hales (who improved the water supply for his village of teddington), and bernouilli (with authored a probability study demonstrating the merits of vaccination) were also interested in public health. but concern about the provision of clean drinking water, adequate treatment of sewage and garbage, and protection against communicable diseases remained the exception rather than the rule, with most countries making a poor showing on indices of population health. francis bacon published studies on the percolation, filtration, distillation and coagulation of water as early as . anton van leeuenhoek described the microscopic animalicules that he had seen in dutch drinking water in , and the french scientist joseph amy patented a water filter in . however, the quality of water in most large cities left much to be desired. philippe de la hire ( - ) mapped the area around paris, seeking to improve the water supply to versailles, probably as much to service the palace ornamental fountains as to provide clean drinking water in the town, and he built a massive aqueduct for this purpose (fig. . ) . he further suggested that householders should install a sand filter to purify the water collected from the roofs of their dwellings, although he noted that one alternative source of water, from underground aquifers, was rarely polluted. in , paisley, scotland became the first british city to establish a municipal water treatment plant. it used a sand filter that had been developed by robert thom. in , paris also constructed a large water treatment facility on the seine; here, river water was allowed to settle for hours, and was then passed through sponge pre-filters and main filters that contained sand and charcoal. despite these advances, the residents of broad st., in central london, faced a massive outbreak of cholera as late as , because they were drawing water from a shallow well that was located close to a cholera-contaminated cess-pit. too often, the city dwellers of the enlightenment continued to pass sewage into open gullies or cess-pits that were fig. . ruins of an aqueduct, built by philippe de la hire to improve the water supply to the city of versailles and its royal palace (source: http://en. wikipedia.org/wiki/ canal_de_l'eure) close to wells, and garbage was thrown directly onto the street. however, in , the conseil supérieur of new france ruled that in order to reduce infection, the houses in quebec city must have latrines, and that garbage must be carried to the river st. lawrence, rather than simply thrown out of the door. populatiion health during the enlightenment vital statistics provide simple objective indices of overall population health during the enlightenment. at birth, the average european could expect to live no more than years. a third to a half of the population died before reaching the age of years. those who survived to their mid-teens lived into their s or even their early s, and at the age of the aristocracy could expect to live a further - years; this was an improvement over the years of adult survival typical of the fourteenth century. survival prospects were much worse in north america than in europe during the enlightenment. many of the population succumbed to fevers, intestinal diseases, and, in the case of the african slaves, to harsh working conditions. a quarter of european immigrant children did not survive until their first birthday, and half of all marriages ended in the death of one partner before their seventh wedding anniversary. epidemics of beri-beri, smallpox, malaria and yellow fever wreaked havoc among early colonists. two of every three deaths were attributed to typhoid, dysentery or salt poisoning. in an attempt to reduce this terrible toll, newly arrived immigrants were initially isolated in "guest houses." replacement of contaminated water by wine, beer or cider, a reduced consumption of infected clams, and a scattering of the population to areas where there were copious fresh water springs reduced deaths from typhoid and dysentery, but progress in reducing overall mortality was slow. in early canada, dispersal of the population along the major rivers made major epidemics less likely than in the urban settlements of the united states, but isolation, accidents and harsh winters made canadian life expectancy worse than those in either europe or the u.s. only a small fraction of the population lived beyond years, and many of the children suffered from rickets and anaemia. typhus and smallpox were also recurrent problems. the victorian era was marked by growing government responsibility for the health of the public in large european cities. there was a gradual improvement in the quality of housing, and demographics showed a burgeoning birth rate. social reformers also succeeded in abolishing child labour and slavery from western society (chap. ). in this section, we will discuss the role of boards of health, continued deaths from poisoning, and improvements in housing conditions. major epidemics of influenza, cholera, typhus, typhoid fever and scarlet fever sparked a deep concern about population health in victorian england. in london, england, cholera killed , people in - and , in (chap. ). however, leaders of a new sanitary movement such as edwin chadwick ( - ) and thomas southwood smith ( - ) began to recognize that ill-health of the individual soon became ill-health of the population. they thus made urgent calls for the provision of clean drinking water, proper removal of refuse and sewage treatment. chadwick and smith sat as commissioners on london's general board of health that regulated the water supply and sewer connections for all new housing in the city, and provided adequate burial grounds for those who died. the quality of london's drinking water was rapidly upgraded, and money was spent on methods of preventing death during childbirth. the public health acts of and also established public baths and wash-houses, and by the s, health-conscious municipalities were building public swimming pools. in lower canada (quebec), a physician was appointed as health officer in , with the primary responsibility of monitoring the sick and starving people who were arriving on immigrant ships from europe. by , a strengthened five-member board of health was supervising quarantine arrangements on grosse isle, in the st. lawrence river near to quebec city. nevertheless, the number of immigrants was such that this holding facility was at times overwhelmed, and cholera periodically reached quebec and montreal, killing between - % of the population. in , people also died of typhus while they were quarantined at grosse isle. a central board of health for both upper and lower canada was created in . compulsory vaccination against smallpox was introduced in the early s. in the united states, organization of sanitary reform began rather later than in canada. the city of new york enacted the metropolitan health bill in , creating a -person board of health. immigrants were processed on ellis island, just outside new york city. the original wooden structure was quickly destroyed by a catastrophic fire, but a stone replacement building opened in . many immigrants spent only a few hours in the facility, but those with contagious disease were summarily denied admission to the united states. continued deaths from poisoning many victorians died from eating adulterated or diseased food. one report to the british privy council ( ) estimated that % of meat came from diseased cattle. flour was expensive, and bakers frequently adulterated it with chalk (to whiten it) and alum; often, the bakers also kneaded the mixture with their bare feet. an act prohibiting the adulteration of food was passed in , but its enforcement was an option for local authorities, so that it was not very effective. cooking was typically done in tin-lined copper pans; wealthier citizens replaced the pots when the tin had worn away, but the poor could not afford to do this, and in consequence they sometimes developed copper poisoning. other sources of poisoning in the victorian home were leaking gas pipes, lead used in white paint, and arsenic used to colour wallpapers. in the early nineteenth century, the sudden influx of country folk into the major cities of europe created hideous slums: "in big, once handsome houses, thirty or more people of all ages may inhabit a single room." housing gradually improved over the victorian era, as many workers accumulated sufficient funds to purchase modest but well-built homes. enlightened industrialists also constructed model housing estates for their employees. robert owen ( - ) organized a model community for his workers at the new lanark mills, in scotland, complete with a nursery school. he envisaged an even more ambitious employee housing project in new harmony, in, but this project failed within two years. the quaker chocolate manufacturer george cadbury ( - ) built a model village for his employees around his factory at bournville, near birmingham, and in the u.s. george pullman, the railway carriage czar, built a model town at pullman, il, in . charitable foundations such as the peabody trust began to replace the worst of london's slums with solidly-built if spartan apartments (fig. . ). the first peabody block, at spitalfields, included dwellings for the poor, shops complete with accommodation for the shopkeepers, and on the top floor baths and laundry facilities for a total cost of £ , . in the united states, building codes were improved during the victorian era, and a national housing association was founded in , under the aegis of the commission on the congestion of population in new york. there were also attempts to persuade philanthropists to build model tenements at low rents; buildings were bought, renovated, and then rented to relocated slum dwellers who were given "friendly instruction" on management of their new households. despite substantial progress in the delivery of public health, there remain a number of continuing challenges in the twenty-first century. current issues include the definitive control of the sales of tobacco and mood-altering drugs, the regulation of automotive emissions and other source of urban air pollution, management of the hiv/aids epidemic, concern over a growing reluctance to accept childhood vaccinations, and the management of infections spread by international air travel. in the edwardian era, cigarette manufacturers had promoted their wares as the cure for various respiratory conditions such as asthma and hay fever. but in , the american physician isaac adler pointed to a growing incidence of lung cancer, and he speculated that the abuse of tobacco and alcohol might be responsible. anti-smoking groups developed in germany following world war i, and a magazine (german tobacco opponents) was published from to . the nazi regime was opposed to smoking, with hitler declaring it a waste of money. in particular, women who smoked were considered as unsuitable to be german wives and mothers. during world war ii, the axis powers made much propaganda from the fact that hitler, franco and mussolini were non-smokers, whereas churchill, roosevelt and stalin were all heavy users of tobacco. evidence of the toxicity of tobacco steadily accumulated during the modern era. in , fritz linkint dresden demonstrated an increased prevalence of lung cancers in smokers. his research was confirmed in , with a case-control study by franz hermann muller of cologne. during the s, ernst wynder at the sloan-kettering institute in new york and richard peto and bradford hill at oxford university advanced even more compelling evidence that cigarettes were carcinogenic. hill concluded that consuming cigarettes per day increased the odds of dying from lung cancer as much as forty-fold. other damning evidence came from cellular pathology, animal experimentation and the demonstration of toxic chemicals in cigarette smoke. however, for a substantial part of the post-modern era, public health workers had to combat a deliberate campaign by the cigarette manufacturers to confuse and deceive the general public. the manufacturers were well aware of the damning facts by the early s, but their misleading propaganda was able to increase u.s. cigarette sales to a peak of billion units in . as late as , only a third of u.s. doctors considered smoking as "a major cause of cancer," and % of physicians were still smoking on a regular basis. beginning in the mid s, there was a dramatic decrease in the social acceptability of cigarette smoking, and growing restrictions were placed on public areas where smoking was permitted. this resulted from demonstrations that passive exposure to cigarette smoke gave rise to small but significant increases in the risks of chronic respiratory disease and asthma in childhood, and carcinoma of the lungs and cardiovascular disease in adults. public polls showed a growing acceptance of public health measures to control smoking in public spaces. cigarette manufactur-ers went to particularly great pains to obfuscate the risks of passive exposure to cigarette smoke, but adverse effects were clearly demonstrated during the s, not only by epidemiological research, but also by the exposure of volunteers to machine-generated cigarette smoke while they exercised in closed chambers. public health workers continue to face many challenges in reducing the sales of tobacco products, as manufacturers doggedly resist measures to reduce consumption through increased taxation, prohibition of sponsorships, and plain packaging. they constantly seek methods of creating new addicts, both through extensive advertising in third world countries and through such tactics as the marketing of electronic cigarettes. as recently as , cigarette smoking still accounted for . % of deaths world-wide. the toll from cigarettes is now compounded by the effects of mood-altering drugs. several countries (including canada) have abandoned attempts to prohibit the marketing of marijuana, with as yet no clear standards of dosages compatible with worker and road safety, and an ever growing segment of the north american population is becoming addicted to powerful opiates, with a high risk of deaths from overdoses. british columbia alone had deaths from opiate overdoses in , despite providing emergency workers with supplies of the antidote naloxone. the modern era saw a dramatic drop in the sulphurdioxide/large particulate smog associated with coal fires in many developed societies, but air pollution problems have continued from coal-fired power station and sautomotive emissions, particularly during thermal inversions. the exposure of cyclists and pedestrians to carbon monoxide was studied during the s. substantial concentrations of carbon monoxide were recorded on congested city streets, particularly if air movement was impeded by tall buildings, but any build-up of carboxyhaemoglobin in the blood stream was reversed quite quickly when the individual moved to a less polluted area. the only adverse clinical effect from carbon monoxide exposure was a somewhat earlier onset of angina if a person with coronary atherosclerosis exercised on a heavily polluted street. chamber experiments by steve horvath in santa barbara, ca, and larry folinsbee in toronto documented acceptable ceilings of exposures to the ozone that was formed by the action of sunlight upon the nitrogen oxides from vehicle and aircraft exhaust. the threshold concentration causing a minor disturbance of respiratory function in healthy exercisers was around . p.p.m., a level that was exceeded in some north american cities on heavily polluted days. to date, in many cities improved automotive emission controls have done little more than match the increase in vehicle registrations, and places such as paris and beijing have needed to forbid the access of drivers to the centre of cities on alternating days in order to reduce pollution levels. since ozone levels show a marked diurnal cycle, one immediate remedy for the active individual is to exercise at less heavily polluted times of the day (early morning or late at night). the ultimate solution to the problem of automotive exhaust probably lies in the replacement of gasoline-driven by electric or hydrogen-powered vehicles. the hiv/aids epidemic officially began in the u.s. in , when the centers for disease control reported a clustering of cases of pneumocystis pneumonia among homosexual men in los angeles. it was quickly realized that the condition was not limited to homosexual individuals, but was seen also in intravenous drug users, haemophiliacs and others receiving blood transfusions. thus, in august , the cdc coined the new term aids. a year later, luc montagnier and his associates at the pasteur institute in paris discovered the virus responsible for this disease. much effort has since been devoted not only to finding highly effective antiretroviral agents, but also in devising measures to reduce transmission of the disease. particular emphasis has been placed upon the wearing of condoms during sexual intercourse, in providing sterile needles for intravenous drug users through programmes of needle exchange and supervised injection sites, in closer control of blood banks and in ensuring sterility during drug injection treatments of tropical diseases. nevertheless, success in controlling the epidemic has as yet been only partial. in the u.s. the disease had already claimed , lives by ; a further million were living with the disease, and , fresh cases were diagnosed in that year. in rural africa, the situation remains even worse, with as many as a third of young adults currently infected. during the early part of the post-modern era, successful childhood vaccination campaigns brought the incidence of mumps, measles and rubella to a very low level in most developed countries, and the who set the year ce for the total elimination of measles and rubella from the european region. however, the percentage of children receiving vaccination has decreased in recent years, with parents weighing the low current risk of infections relative to the supposed dangers of developing meningo-encephalitis and autism. fears that vaccination would cause autism stemmed from a paper published by the british physician andrew wakefield, in . extensive research found no evidence to support his claims, and the british medical journal recently declared that the original article was fraudulent. further, the british general medical council found wakefield had been guilty of serious professional misconduct, and he was struck from the medical register. there have since been small outbreaks of measles consequent upon the decreased proportion of vaccinations in britain and in canada, and unfortunately many of the general public remain convinced that vaccination can cause autism. infectious diseases can now spread very rapidly, due to the ever-growing number of people who engage in global air travel. this problem is well exemplified by an epidemic of sars (severe acute respiratory syndrome). this began in mainland china in november of , and due to delayed reporting by the chinese authorities it spread rapidly around the world. the who issued a global health alert on april th . fortunately, application of rigid quarantine measures contained the epidemic, with relatively few deaths in north america, and by july th , the who was able to declare that the sars epidemic was over. many of the major epidemics of earlier eras were due largely to poor hygiene-a lack of clean water, poor sewage treatment, and an inadequate control of people who were already infected. although we often assume that these issues have now been resolved, it is important to recognize that in many third world countries supplies of clean water and adequate supplies of food are still lacking, with shortages often exacerbated by ethnic conflicts. the same issues of clean water, waste disposal and burial of the dead could still arise in wealthier countries today if there were to be an earthquake, a typhoon or a tsunami, and emergency services must be prepared to give the highest priority to an early re-establishment of the basic health infrastructure following any natural disaster. issues in the adulteration of food have now been largely overcome in developed society, but the current obesity epidemic underlines that problems still have to be resolved in terms of persuading food processors to avoid tactics designed to persuade consumers to overeat. for those who can afford housing, the modern single-family home is generally well-equiped to optimize the health of those who are living in it. massive tower blocks are less suited to a healthy and active life-style, particularly for families with young children. moreover, ever-increasing minimum specifications for housing, a growing world population and a lack of land is presenting public health agencies with the issue of a growing proportion of homeless individuals in many large cities. globalization is presenting new challenges to public health, not only with the rapid spread of infections, but also with the international enforcement of regulations on issues ranging from emission controls on cars to the quality of foods and medications. the ideal forum for developing appropriate preventive measures would seem the world health organisation, but unfortunately (as with many international bodies) its effectiveness is often limited by political considerations, including threats from some nations to slash funding unless criticism of their practices is shelved. . are the infrastructure constraints of an earlier era still compromising public health in third world countries? questions for discussion child against measles, mumps and rubella? what will be the likely new challenges to public health agencies over the next years? public health foundations: concepts and practices cigarette smoking: health effects and challenges for tobacco control plague and the poor in renaissance florence principles of water resources bathing in public in the roman world mission and method: the early nineteenth century french public health movement history of hygiene asian medical systems: a comparative study hygiene in the early medical tradition public health victorian medicine and popular culture private choices and public health. the aids epidemic in an economic perspective health, civilization and the state; a history of public health from ancient to modern times the nazi war on cancer housing in urban britain environmental policy and public health: air pollution, global climate change and wilderness a history of public health shephard rj. the risks of passive smoking on the mode of communication of cholera the new public health the establishment of a board of health for new york city in further reading some early societies had an infrastructure that provided clean water and the removal of sewage, but since this was usually available only to wealthy citizens, its impact upon the course of epidemics was limited. major cities such as london did not build a comprehensive infrastructure until the middle of the victorian era, when appropriate initiatives were taken by newly formed boards of public health. although the traditional concerns of public health have now been largely met in developed societies, new challenges are constantly arising. these include the control of tobacco products and mood-altering drugs, the reduction of automotive emissions and other forms of urban pollution, management of the hiv/aids epidemic, overcoming a growing reluctance to vaccinate infants, and countering the rapid spread of infections by air travel. key: cord- -seirbkiq authors: tuncer, necibe; le, trang title: effect of air travel on the spread of an avian influenza pandemic to the united states date: - - journal: international journal of critical infrastructure protection doi: . /j.ijcip. . . sha: doc_id: cord_uid: seirbkiq abstract the highly pathogenic avian influenza (hpai) strain h n , which first appeared in hong kong in , achieved bird-to-human transmission, causing a severe disease with high mortality to humans [ ]. according to the world health organization (who), a total of cases were reported in fifteen countries, including deaths, corresponding to a case fatality rate of nearly % [ ]. avian influenza continues to be one of the deadliest diseases that jumps from animals to humans. epidemiologists believe that it is likely to cause the next major global pandemic that could kill millions of people. the outbreak of severe acute respiratory syndrome (sars) demonstrated that international air travel can significantly influence the global spread of an infectious disease. this paper studies the effects of air travel on the spread of avian influenza from asian and australian cities to the united states. a two-city mathematical model involving a pandemic strain is used to derive the basic reproduction number ( r ), which determines if the disease will spread and persist ( r > ) or go extinct ( r < ). real air travel data is used to model the disease spread by individuals who are susceptible to or are infected with pandemic avian influenza. analysis of the two-city model helps understand the dynamics of the spread of pandemic influenza when the cities are connected by air travel. understanding these effects can help public health officials and policy-makers select the appropriate disease control measures. also, it can provide guidance to decision-makers on where to implement control measures while conserving precious resources. the avian influenza virus belongs to a group of viruses known as influenza a that circulate in many avian and mammalian species, including humans [ ] . the highly pathogenic avian influenza (hpai) strain h n achieved bird-tohuman transmission and caused a severe disease to humans with high mortality [ ] . hpai first appeared in in hong kong, where it infected eighteen humans and caused six deaths. to date, a total of cases in fifteen countries have been reported to the world health organization (who), including deaths with a case fatality rate approaching % [ ] . interestingly, there has been no decline in the mortality rate since the first appearance of hpai. in march , china reported several confirmed cases involving the h n strain that had not been seen previously in humans [ ] . most patients showed flu-like symptoms, and a throat swab taken from a patient in jiangsu province revealed the presence of the h n human influenza virus and the h n avian influenza virus [ ] . avian influenza continues to be one of the deadliest diseases that links humans and animals. indeed, it is expected to cause the next major influenza pandemic. an influenza pandemic occurs when a new strain of virus circulates among humans, potentially killing millions of people. aside from its high mortality rate, avian influenza is monitored closely for a pandemic because influenza a type viruses can evolve rapidly and jump between species. the viruses evolve through evolutionary mechanisms such as drift and shift. drift involves small, gradual changes to surface proteins while shift involves abrupt major changes to the influenza virus. shift evolution occurs through reassortment, the mixing of two influenza viruses (e.g., avian influenza and human influenza) into a new strain that carries properties from both strains. shift typically occurs when a patient gets infected with both strains of the influenza virus. recent outbreaks in china show that shift evolution can occur at any time with potentially deadly effects. vaccination is one of the best ways to prevent the spread of pandemic influenza and reduce its severity. however, producing live attenuated and inactive vaccine seed viruses against a potential pandemic-causing avian influenza strain, and subsequently performing pre-clinical tests and clinical trials can take several months, if not longer. unfortunately, it is not possible to predict which avian virus strains will cause the next influenza pandemic or when the pandemic will occur. of great concern is the fact that once pandemic avian influenza surfaces, it will spread globally in no time at all because the world is connected via air travel. the outbreak of severe acute respiratory syndrome (sars) demonstrated that international air travel accelerated the global spread of an infectious disease [ ] . this paper attempts to study the effects of air travel on the spread of avian influenza. understanding the effects can help public health officials and policy-makers to select the appropriate disease control measures. also, it can provide guidance to decision-makers about where to implement control measures while conserving precious resources. this paper presents a mathematical model with spatial heterogeneity that is designed to better understand the emergence and the spread of pandemic avian influenza. spatial effects regarding disease spread can be modeled by diffusion or dispersal models. in a diffusion model, the movements of infected individuals are instantaneous and the disease spreads immediately to neighboring areas. on the other hand, in a dispersal model, the movements of individuals are discrete and usually occur between so-called patches connected by dispersion. dispersal models are more appropriate when considering travel over long distances. thus, a two-city dispersal model is developed to predict the spread of avian influenza from asia and australia to major u. s. cities via air travel. real air travel data is used to model the disease spread by individuals who are susceptible to or are infected with pandemic avian influenza. the two-city model helps identify the most effective intervention strategies at the origin and destination cities as well as help quantify the effectiveness of control measures that should applied to reduce the morbidity and mortality of a pandemic. this can provide valuable guidance to public health officials and policy-makers as they decide how, where and when to target pandemic influenza intervention strategies while efficiently using the available resources. this section describes the mathematical model, and the data and model parameters. a two-city model is used to express the spread of avian influenza from its origin in an asian or australian city to major cities in the united states. a single-city model is first specified, which is subsequently generalized to a two-city model by considering the travel of susceptible and infected individuals with the new strain of avian influenza. avian influenza, one of the most dangerous diseases that links humans and animals, is currently the foremost pandemic threat. early mathematical models that investigate the impact of a hypothetical pandemic have focused only on humans [ , , , , ] . at this time, the avian influenza virus can only be transmitted from birds to humans; it is not yet capable of sustained human-to-human transmission. most of the human cases reported to the who were due to close contact between humans and domestic birds. recent mathematical models capture the bird-to-human transmission pathway of avian influenza [ ] [ ] [ ] [ ] . the simplest bird-tohuman model was introduced by iwami et al. [ ] ; this model is the starting point for the single-city model presented in this paper. the notation used in our model is different, but the two models are equivalent. in our single-city model, the domestic bird population is divided into two non-intersecting classes: susceptible domestic birds denoted by s d (t) and infected domestic birds denoted by i d (t). the natural birth rate of the bird population is expressed by Λ d . susceptible birds have a natural death rate μ d while infected birds die at the rate μ d þ ν d , where the additional death rate ν d is induced by hpai. susceptible humans are denoted by s(t) and infected humans by i(t). the natural birth rate of the human population is denoted by Λ. susceptible humans die at the rate μ while infected humans die at the rate μ þ ν, where ν is the additional death rate due to avian influenza. the single city model, which comprises the bird and human populations, is given by the force of the infection in the domestic bird population is denoted by β d i d s d , where β d is the transmission rate at which a susceptible bird contracts avian influenza from an i n t e r n a t i o n a l j o u r n a l o f c r i t i c a l i n f r a s t r u c t u r e p r o t e c t i o n ( ) - infected bird. the incidence rate in the human population is denoted by βi d s, where β is the rate at which a susceptible human contracts avian influenza upon contact with an infected bird. to investigate the impact of a hypothetical pandemic, we assume that avian influenza evolves to become a human-tohuman transmissible pathogen. this evolution likely occurs as a result of one of two evolutionary mechanisms: drift and shift. we assume that the mutation of avian influenza is caused by reassortment (shift mechanism) and denote the mutation rate of avian influenza into a pandemic influenza by m. the new avian influenza strain that causes a pandemic is called "pandemic avian influenza." the human population that is infected with the new strain is denoted by p(t). infection from one strain of influenza a virus provides cross-immunity to infections from other strains. this is why we assume that humans infected with pandemic avian influenza can infect susceptible humans, but not humans who are infected with avian influenza. the new incidence of pandemic avian influenza is denoted by β p ps, where β p is the transmission rate. the additional death rate due to pandemic avian influenza is denoted by ν p . table lists the state variables in the model while table lists the model parameters. the two-city model assumes that the pandemic originates in a city in asia or australia and spreads to a city in the united states by air travel. we only consider the air travel of susceptible and infected humans with pandemic avian influenza because the infected individuals can only contract the disease from domestic birds (that do not travel). if the travel of humans is not considered, then the pandemic is modeled within each city by a single-city model. in the following, we use subscripts to distinguish cities. the travel rate of individuals from city to city is denoted as k and the corresponding travel rate from city to city is denoted by k . the two-city model is given by we assume that individuals infected with pandemic avian influenza have minor flu-like symptoms and, therefore, are "well enough" to continue with their travel plans. thus, the travel rate for infected individuals is the same as that for susceptible individuals. fig. shows the movements of individuals between city and city through the various stages of the disease. in the model, the transmission of pandemic avian influenza occurs only between individuals in a city. specifically, infected individuals in one city do not directly infect individuals in another city. this assumption is motivated by the fact that individuals in a city are much more likely to be in contact with city residents than touriststhe number of contacts between city residents is extremely large compared with the number of contacts between residents and tourists on a given day. we also assume that the transmission rates of avian influenza within the bird and human populations, and the transmission rates of pandemic avian influenza are the same for all cities. international airline flight data provided by the office of the secretary for aviation and international affairs was obtained from the united states department of transportation website [ ] . tables and present flight data obtained from the report entitled "u.s. international air passenger and freight statistics" for the third quarter of . table lists the numbers of passengers who took direct flights from asian or australian cities to u.s. cities. table shows the numbers of passengers who traveled from major airports in asia and australia and the corresponding u.s. shares expressed as percentages. the travel rates between city (k ) and city (k ) are estimated by dividing the total number of passengers traveling from city to city by the population of city . since time is measured in days, the result is further divided by to obtain the travel rate of individuals of a city per day. the populations of cities considered in this work are presented in table . for example, the travel rate from seoul to los angeles is estimated as similarly, the travel rate from los angeles to seoul is estimated as the lifespan of humans varies from country to country, and even from city to city. table lists the life expectancies of the countries considered in this research. the natural death rate of humans is estimated as according to the who, the duration of the infectious period for hpai-infected human cases is six to seven days. therefore, the disease-induced death rate of hpai is taken to be ν ¼ : ¼ : days À . we adjust the disease-induced death rate as a result of pandemic avian influenza using ν p ¼ : , which is taken from [ ] . thus, we assume that the death rate caused by the new strain of avian influenza is smaller than the death rate of hpai. the who gives the infectious period of domestic birds to be ten days, so ν d ¼ : days À . the natural death rate and the disease-induced death rate are assumed to be the same for all cities. the total human population nðtÞ ¼ sðtÞ þ iðtÞ þ pðtÞ satisfies the differential equation: upon solving eq. ( ), we see that the total human population is a bounded function of time: where n is the initial human population. the limit of the human population is applying similar analysis to the total bird population n d ðtÞ ¼ s d ðtÞ þ i d ðtÞ, we obtain in all the simulation results presented in this paper, the bird population is given in units of domestic birds and the human population is given in units of individuals. eqs. ( ) and ( ) are used to estimate the recruitment rates for the bird and human populations, respectively. the food and agriculture organization [ ] gives the total poultry population as . billion, which corresponds to in units of . commercial poultry is usually kept for two years, so the natural death rate of birds is μ d ¼  days À . therefore, we estimate the recruitment rate for the bird population as the recruitment rate of humans in each city is computed similarly using the population and life expectancy data given in table . the cumulative number of hpai-infected human cases reported by the who exhibits seasonality [ ] . this is likely due to factors such as temperature, rainfall, migration patterns of wild birds, survival of the hpai virus in the environment and seasonality in bird-to-bird transmission. several such mechanisms are considered in [ ] to understand the reasons for the seasonality in avian influenza data; the authors report that the main culprit is bird-to-bird transmission. we use their fitted parameter values for the bird-to-bird and bird-to-human transmission rates, which are β d ¼ :  À and β ¼ :  À , respectively [ ] . in the case of pandemic avian influenza, we set the humanto-human transmission rate to β p ¼  À . this is a purely hypothetical value because there is no good way to estimate it. the parameter is fixed by assuming that the transmission of the new pathogen is higher than the transmission of the current pathogen. currently, avian influenza is in the zoonotic stage, meaning that the only transmission pathway is from birds to humans. the new pathogen evolves into a strain that is capable of human-to-human transmission. we use the mutation rate m¼ . as given in [ ] . all the simulations reported in section use the parameter values listed in this section. we only change β d or β p to vary the simulations when necessary and the changes are mentioned whenever they are applied. epidemiologists are interested in the long-term dynamics of the spread of an infectious disease. by studying the solutions of the mathematical model, we hope to answer the question of whether the disease will die out or persist in the bird and human populations. in particular, we want to measure the severity of the hypothetical pandemic caused by avian influenza. to predict the severity of an outbreak or pandemic, a summary parameter called the reproduction number is calculated from the population model. the reproduction number i n t e r n a t i o n a l j o u r n a l o f c r i t i c a l i n f r a s t r u c t u r e p r o t e c t i o n ( ) - r is an epidemiologically important threshold value that determines whether a disease will persist or die out. the basic reproduction number gives the secondary number of infections produced by one infected individual in a totally susceptible domain during her/his infectious period. if r o , then the disease-free equilibrium is locally asymptotically stable, meaning that the disease will eventually become extinct. if r , then the disease-free equilibrium is unstable and the disease will persist in the population. determining an expression for the basic reproduction number and estimating its value are important when selecting the most effective control measures for eliminating a disease. reproduction numbers are derived by performing a qualitative analysis of a mathematical model. the procedure is described in detail in the following sections. the first step in the qualitative analysis of the model is to find constant solutions that do not change in timeequilibrium points. equilibrium solutions for the single-city model have been studied in [ ] and will not be repeated here. however, we will summarize the model dynamics. the disease free equilibrium (dfe) for the single-city model is ðs n d ; ; s n ; ; Þ, where s n d ¼ Λ d =μ d and s n ¼ Λ=μ. the basic reproduction numbers for the bird population r b and the human population r h , respectively, are that is, if r o and r h o o , then the dfe vanishes in both populations; otherwise, the disease becomes endemic. this paper focuses on the dfe of the two-city model. the equilibrium points for the two-city model satisfy the following steady-state equations, which are derived by setting the time derivatives equal to zero: we denote the dfe equilibrium by ε n ¼ ðs n d ; ; s n ; ; ; s n d ; ; s n ; ; Þ, where this is the state in which hpai and pandemic avian influenza are both wiped out in the bird and human populations. this infection-free state is stable if the reproduction numbers for the bird and human populations in both cities are less than one. the basic reproduction numbers for the bird populations in city and city are given by for a system with multiple infected compartments, as in the two-city model defined by eq. ( ), the reproduction number is defined as the number of infections produced by one infected individual at the dfe [ ] . following the next generation approach described in [ ] , we classify the compartments as infected and uninfected. in our case, the infected compartments consist of birds infected with hpai, humans infected with hpai and humans infected with pandemic avian influenza. we define two matrices: (i) f, which expresses the rate of new incidences; and (ii) v, which represents the transfer of individuals between compartments: the principal eigenvalue of the next generation matrix fv À is the basic reproduction number. the next generation matrix for the two-city model in eq. ( ) is in which the reproduction numbers for the human populations in city and city are given bŷ we take the basic reproduction number for the human population to be the maximum of the reproduction numbers for the two cities: fig. san francisco :  À tokyo :  À fig. united states . tokyo :  À fig. united states . seoul :  À fig. united states . hong kong :  À fig. united states . sydney :  À fig. united states . beijing :  À similarly, the reproduction number for the bird population is r ¼ maxfr ; r g: hpai and pandemic avian influenza both become extinct in the bird and human populations when all the reproduction numbers are less than one. the preceding mathematical discussion leads to the following important result. theorem . if r o ; r o , then the dfe ε n is locally asymptotically stable. if r or r , then the dfe ε n is unstable. sensitivity analysis of the model predictions to small changes in parameter values can help determine which parameters are the best targets for controlling the disease and slowing an epidemic. let λ be a quantity that depends on two parameters of different scales, i.e., λ ¼ λðp; qÞ. then, the sensitivity of λ with respect to the parameters p and q is given by the sensitivity s λ p gives the amount of change that occurs in λ in response to small changes in p. however, because p and q are parameters with different scales, the effect of changes in p and q on λ cannot be compared easily. therefore, we use an alternative measure that allows for the comparison of different scales. the normalized sensitivity, which is also called elasticity, of the quantity λ with respect to parameter p is given by the elasticity e λ p describes how the quantity λ is affected by small changes in p. a negative elasticity means that a onepercent increase in the parameter p results in an e λ p % decrease in λ. similarly, a positive elasticity means that a one-percent increase in the parameter p results in an e λ p % increase in λ. in the following section, we derive analytic expressions for the elasticities of the basic reproduction number and the prevalence of pandemic avian influenza. the elasticity values are analyzed in the context of the simulation results. this section presents the numerical simulation results for the two-city model. the two-city model was solved numerically using the ode s built-in function provided in matlab b. the parameters were set to the values described in section . in the simulations, a small initial infection was introduced in the origin city of the pandemic, and it was assumed that no infected cases exist initially in any of the u.s. cities. a total of fourteen simulations were conducted for the spread of the pandemic spanning a period of ten years. the reproduction number for the bird population was computed to be r ¼ : . the computed reproduction numbers for humans in the various cities are shown in table . the fact that the bird population reproduction number is greater than one (r ¼ : ) suggests that the dfe is unstable, and this is in agreement with the corresponding simulation results (figs. - listed in the last column of table ). in each of these figures, subfigure(a) shows the number of infected individuals with pandemic avian influenza in the origin city while subfigure(b) shows the number of infected individuals with pandemic avian influenza in the destination u.s. city. in the simulations, we see that for the air travel data taken from table , the numbers of infected people in u.s. cities are less than those in the origin cities. on the other hand, when we consider the data from table , it is interesting to see that the situation reverses. this is not surprising because the travel rates differ considerably in the two types of data. tokyo has the busiest air traffic to the united states - . million passengers in just one quarter (table ). this contributes to a high travel rate because the population of tokyo is . million (k ¼ : and k ¼ : ). the next section investigates the effects of air travel on pandemic prevalence in more detail. . . several researchers have studied the state of h n infections in bird populations [ , , ] . these studies suggest that h n infections are at the endemic state in bird populations. as such, the reproduction numbers for the bird populations should be reduced to control the disease. if the reproduction number r is kept below , then an h n infection in a bird population is eliminated. as a consequence, "spill over" infections to human populations are also eliminated [ ] . martcheva [ ] conducted a sensitivity analysis of the reproduction number r and reports the following results: these results suggest that the highest impact on r is obtained by increasing the natural death rate for the bird population μ d . thus, one of the most effective control measures that can be applied to poultry is culling. culling increases the parameter μ d and produces the largest change to r . in the pandemic scenario, the reproduction number r is also an important parameter whose value should be kept below one. however, control measures applied to a bird population may be insufficient to reduce the prevalence of a pandemic. we now develop an analytic expression for the number of infected people with pandemic influenza at the equilibrium state. we call a state in which hpai dies out in the population but pandemic avian influenza persists as the "pandemic-only equilibrium" and denote it by ðŜ d ; ;Ŝ ; ;p ;Ŝ d ; ;Ŝ ; ;p Þ. the pandemic-only equilibrium satisfies the steady-state equations (eq. ( )). thus, the parametersp andp satisfy the following equations: heren i ¼Ŝ i þp i , i¼ , denotes the total population of city i at the pandemic-only equilibrium. to study the effect of the travel parameters k and k on the prevalence of the pandemic avian influenza, we derive the elasticities of pandemic prevalence with respect to the parameter set p ¼ ðβ p ; μ ; ν p ; μ ; ν p Þ. upon implicitly differentiating the functions f ðp ;p Þ and gðp ;p Þ, we obtain the following equations: where the preceding discussion leads to the formulation of the following proposition. proof. at the pandemic-only equilibrium, f ðp ;p Þ ¼ a p þ β pp þ k p ¼ ,p is strictly positive and β pp þ k p , so a o . similar analysis yields a o . from eqs. ( ) and ( ), we obtain the following expression: which states that both ða a Àk k Þ and ∂p =∂k are non-zero as long as a b ðp i ÞÀk b ðp i Þ is non-zero for each parameter p i . from eqs. ( ) through ( ) , it follows that a b ðp i ÞÀ k b ðp i Þ a . moreover, since a a À k k is continuous in all its parameters, it must have a definite signeither all positive or all negative. setting k ¼ k ¼ , we see that a a and, thus, upon solving eqs. ( ) and ( ), we obtain the following analytic expressions for the elasticities of pandemic prevalence: from these analytic expressions, it is clear that the only positive elasticity is for the transmission rate of pandemic avian influenza. the elasticities of pandemic prevalence with respect to parameters μ , μ , ν p , ν p are all negative. these results suggest that control measures that decrease the transmission rate and infectious period of pandemic avian influenza should be applied. examples of control measures that might be applied to stop or limit the spread of pandemic influenza are isolating infected individuals, quarantining susceptible individuals who are exposed to the virus and vaccinating individuals against the pandemic strain. these measures impact different parameters in eq. ( ) . for example, isolation and quarantine affect the transmission rate β p while vaccination reduces the susceptibility of healthy individuals (thus reducing β p ) and might also decrease the infectious period (thus increasing ν p ). evaluating the efficacy of control measures is a non-trivial task for an actual infection, let alone for a hypothetical pandemic avian influenza outbreak. nevertheless, we compute the elasticities of the pandemic prevalence numerically in order to elucidate the efficacy of control measures. first, we compute the number of infected individuals with pandemic avian influenza at the pandemic-only equilibrium ðp ;p Þ with k and k varying from to . in the simulations, city is the origin of pandemic influenza and city is the destination city. then, the elasticities of pandemic prevalence are plotted as functions of k and k . to further visualize the effects of the air travel, for a fixed k value, the elasticities are plotted for varying k values, and vice versa. the simulation results show that, although the analytic expressions for ep β p and ep β p are symmetric, the effects of air travel on the elasticities differ for the origin city and destination city (see figs. (a) and (a) ). the simulation results in fig. demonstrate that isolating and quarantining individuals from the origin city is appropriate when the travel rate out of the city is very small (i.e., when k is small). when k is large (e.g., k : in fig. (a) ), applying control measures aimed at decreasing the transmission rate of the pandemic influenza will not decrease the prevalence of infected individuals, potentially leading to wasted resources. on the other hand, in the destination city, much is gained from isolation and quarantine measures when k is very small. during a pandemic, government agencies in the destination city should consider implementing disease control measures along with restricting travel (see fig. ). next, we consider the elasticities of pandemic prevalence with respect to the disease-induced death rates for each city. since the elasticities are symmetric, we only show the results for origin cities. the simulation results in fig. suggest that vaccination of individuals in the origin city should be considered when the outbound travel rate is very small and the inbound travel rate is very high. vaccinations in the destination city decrease the pandemic prevalence in the origin city only when the travel rate into the origin city is very high (see fig. ). effects of air travel on r we computed the basic reproduction numbers for each origin city and destination city,r andr , using the parameters described in section . . in the following, we take city to be tokyo and city to be a city in the united states, where the transmission rate of pandemic avian influenza in both cities is β p ¼  À . when there is no travel between the two cities, we obtain the same reproduction numbers for each city as when the reproduction numbers are computed for each city in isolation: when k is fixed and k increases,r decreases. the same is true for the reproduction number for city r (see fig. ). according to theorem , if the reproduction numbers for the cities are greater than one, then the disease will always persist. for example, the reproduction numbers for two cities arer ¼ : andr ¼ : when hpai is in the endemic state in the bird population (current state). this scenario is illustrated in fig. (a) , where the higher reproduction number leads to higher prevalence of the disease. in a situation where the reproduction number is greater than one in one city and less than one in another city, then the disease still persists in both cities (see fig. (b) ). next, we investigate the effects of air travel on the elasticities of the reproduction numbers for various cities. if the cities are isolated and there is no travel that links them, then the elasticities of the reproduction numbers r ; r with respect to the parameters β p , Λ , Λ , μ , μ , ν p and ν p are obtained from the analytic expressions given in eq. ( ) : when the two cities are connected via air travel, then the elasticities of the reproduction numbers r ; r with respect to the parameters β p , Λ , Λ , μ , μ , ν p and ν p are obtained from their analytic expressions. the elasticities of the reproduction number for city are the elasticities of the reproduction number for city are as can be seen in the above expressions, the elasticities of the reproduction numbers with respect to the parameter β p are not affected by the travel rates. however, the elasticities with respect to parameters Λ and Λ are affected drastically. consider, for example, fig. (a) and (b) , which illustrate the effects of air travel on er is no air travel, the reproduction number is very sensitive to changes in Λ (er Λ ¼ ). when the two cities are connected via air travel, then the elasticity er Λ drops below . . on the other hand, when the two cities are isolated, the sensitivity of the city reproduction number to Λ is nonexistent, but when the cities are connected, the sensitivity increases above . . the same reasoning holds for city . the elasticity of er νp is À : when there is no air travel. this is a very high sensitivity in the opposite direction, meaning that control measures that decrease the infectious period (e.g., vaccination) result in a large reduction of the basic reproduction number for city . when the two cities are connected, but the travel rate from city is assumed to be zero (i.e., k ¼ and k ), then the elasticity er increases as k increases and decreases as k increases. as fig. (a) suggests, control measures focused on reducing the infectious period are a waste of time and money if the travel rate out of city is high and the travel rate into city is low. in such a case, the best strategy is to vaccinate individuals in city (see fig. (b) ). the two-city model presented in this paper was developed to express and reason about the spread of pandemic influenza from cities in asia and australia to the u.s. via air travel. data obtained from the u.s. department of transportation and who were used to estimate fixed model parameters such as the travel rate, birth rate and natural death rate. model parameters such as transmission rates and hypothetical pandemic death rates were obtained or estimated from fitted values in the literature. the reproduction numbers computed for the bird and human populations (r and r ) are important threshold values. if either r or r , then the disease-free equilibrium is unstable, meaning the disease will continue to persist within the populations. in all the cases considered, although the computed r values are small ( À or less), the r value is . , which suggests that the dfe is unstable; this agrees with the numerical simulation results. the sensitivity analysis involving elasticities helps understand the effects of various parameters on r and pandemic prevalence. the results show that culling, which increases the natural death rate of birds and significantly affects the r value, is the most effective control measure that can be applied to poultry. additionally, control measures such as isolation, quarantine and vaccination should be applied to the human population to reduce pandemic prevalence. isolation and quarantine decrease the transmission rate, while vaccination affects the transmission rate as well as the infectious period. the effectiveness of the control measures, however, depends strongly on the air travel rate. for instance, if the travel rate out of a city is large (i.e., greater than . ), then isolating and quarantining infected and susceptible individuals are not very effective at reducing pandemic prevalence. an expected result is that air travel has a large impact on r . when cities are not connected, the elasticities of the reproduction numbers with respect to recruitment rates are constant (i.e., equal to one). however, when the cities are connected, the elasticities are strongly impacted by air travel. specifically, when the travel rates are positive, the reproduction number for the origin city is very sensitive to changes in destination city recruitment rate, and vice versa. generally, the effects of air travel on the elasticities are different for the origin city and destination city. however, upon examining the effect of the induced pandemic death rate, we discovered that when the travel rate out of an origin city is small, vaccination and other similar control measures in the origin city are ineffective, but vaccination in the destination city is much more effective. thus, combining disease control measures and restricting travel to the appropriate cities is a promising strategy for eradicating pandemic avian influenza. we hope that this paper will stimulate renewed research on understanding the dynamics of the spread of pandemic disease. such research can help public health officials and policy-makers select the appropriate disease control measures, and also provide valuable guidance on where to implement control measures while conserving precious resources. this research was supported by nsf grant dms- . strategies for containing an emerging influenza pandemic in southeast asia fields virology, lippincott-raven food and agriculture organization mitigation strategies for pandemic influenza in the united states assessing the impact of airline travel on the geographic spread of pandemic influenza prevention of avian influenza epidemic: what policy should we choose avian-human influenza epidemic model avian flu pandemic: can we prevent it avian-human influenza epidemic model with diffusion containing pandemic influenza at the source an avian influenza model and its fit to human avian influenza cases avian flu: modeling and implications for control pandemic influenza: risk of multiple introductions and the need to prepare for them the effect of global travel on the spread of sars modeling seasonality in avian influenza h n reproduction numbers and sub-threshold endemic equilibria for compartmental models of disease transmission world health organization, influenza at the human-animal interface world health organization, influenza at the human-animal interface, summary and assessment as of world health organization, overview of the emergence of and characteristics of the avian influenza a (h n ) virus key: cord- -h w jsyd authors: cheshmehzangi, ali title: introduction: the city during outbreak events date: - - journal: the city in need doi: . / - - - - _ sha: doc_id: cord_uid: h w jsyd as the largest quarantine in human history, the city of wuhan, china, with more than million people went under a complete lockdown situation on jan . an unprecedented situation that lasted longer than ever imagined. this occurred solely due to the spread of the novel coronavirus disease (later renamed as “covid- ”), just one day before the celebration of the chinese new year. events. from the beginning, as the cities prepared themselves to control the spread of the disease, their resilience for other aspects became more vulnerable. hence, the city authorities needed to pay more attention and have better preparedness in place, as it is only a matter of days or weeks before a city could literally collapse. in their report on 'health emergency and disaster risk management framework', the world health organisation (who) ( ) announced that from to , a total number of , outbreaks were recorded across countries. this was later increased with a further cases in before we experienced the newest outbreaks in china and nigeria in late and early . the numbers are not something that we see in our daily news reports but are certainly very alarming in many ways. it also proves how frequent we face outbreak events, and how important it is for us to study various methods of tackling the outbreak impacts on our cities and communities. in an outbreak event, whether we deal with epidemic and pandemic events, cities suffer tremendously, societies can become extremely vulnerable, and economies can fail. till the time normalisation can happen, there may be a lot of losses-from human life losses to impactful economic losses. globally, there is no single city with an adequate healthcare capacity that can accommodate thousands of infected patients, set aside a scenario in which millions of people are infected in relatively small proximity of the city level. it has been proven that even the least deadly disease can spread at a gradual pace and have a gradual increase in mortality rates. this can occur mainly due to a lack of healthcare infrastructure (comprised of both capacity and provision) to accommodate larger groups of patients at the same time. in a similar situation, the city of wuhan struggled to maintain the needs of patients in a timely manner. an example of which was the attempt to build a hospital in less than a week, indicating the importance of disaster management strategies and the need for urgently increasing the capacity of the healthcare infrastructure and facilities. in such events, time is exceptionally scarce and responses need to be fast. unfortunately, not all responses will be accurate in this process and not all can respond effectively. nevertheless, the process needs to happen at a large scale, and covering a range of factors; particularly if there were no or little preparedness in place. in this process, decisions are made rapidly but carefully. they are often short-lived or temporary, while the situation remains uncertain during multiple phases of the outbreak event. these phases will be discussed more thoroughly in the next chapter. in general, the second generation of human-to-human cases in an outbreak event may raise new concerns about the handling of the situation. as such, containing the disease is no longer the only priority. more than ever, the city would then need to focus on enhancing the resilience of multiple aspects and manage the situation promptly. hence, urban resilience and city management measures are highly important, as they can essentially save 'the city in need'. such an approach requires holistic planning with its three primary characteristics of ( ) predictive, ( ) prescriptive, and ( ) preventive. in an attempt to strengthen urban health resilience, such outbreaks require urgent attention to maintain and support the needs of residents, visitors, and those who are directly and indirectly affected. this requires the city's preparedness to maintain and manage multiple and essential city systems, such as health, food and clean water (including both supply and delivery), assets, medical support, safety and security, and social stability. most importantly, this requires people's resilience and how society can handle the situation effectively. through many global examples of outbreak events, we verify that (urban) resilience should be strongly backed up by regional management and national strategies. it requires support both internally and externally. this needs to be planned and implemented in a network of multiple stakeholders, enabling the resilience to be at multiple levels and considering multiple health aspects. throughout the whole process of an outbreak, we need to have careful measures for urban resilience; and these should be holistic and inclusive to better contain people, health, infrastructure, and management of the situation. this book is an immediate response to a major pandemic outbreak event at the dawn of this new decade. it started as an outbreak in the central part of china. it did not take long for it to be an epidemic event. it remained as a case of the epidemic for about two months, before it was characterised and declared a pandemic. it took more than two months for the infected cases to reach , cases globally. but then it took less than two weeks to double the number of cases, and only a few days till it passed , cases. the numbers were then much higher than initially expected. this declaration of change from epidemic to pandemic was due to deep concerns about the irrepressible spread of the disease and its severity, lack of resilience, and alarming levels of inaction at the global level (who b). this decision was believed to be delayed already (announced on th of march ), which marks a difference between reality and realisation. however, we are rest assured that there are lessons to be learned from what has been done in the past, what has been experienced, and what can be done in the future. in all cases, cities play a major part in managing the situation as well as to avoid the widespread disease, and to contain the situation as promptly as possible. all these require careful planning. but before we delve into the details, this chapter will serve as an introduction to first explain what is 'outbreak event'? and how it differs from other events and patterns of large scale outbreaks, such as an epidemic, pandemic, and endemic? afterward, the following sub-sections will explain the issues associated with city vulnerability and urban resilience. this is narrated through a broader understanding of theories, literature review, and current practices. this chapter will conclude with an overview of three r's in the practice of urban resilience, namely 'reflections', 'readiness', and 'responses'. the eventual discussions of this chapter will set a good foundation for the following chapters in order to assess the multiple stages of outbreak events and provide a range of theoretical and practical suggestions. the later suggestions are shaped around the idea of a comprehensive urban resilience framework in outbreak events, which is novel in the field of resilient cities and health-related city management scenarios (e.g. health emergency and health crisis). but before we do so, it is important to understand the definition of outbreak event and how it differs from other definitions in the field. there are common misinterpretations between different health-oriented and disease events. in the field of epidemiology, a typical outbreak event is defined as the sudden spread of a contagious disease that occurs at a particular spatial scale in a certain period. epidemiology itself is an interdisciplinary field, bridging between scientific disciplines like biology, statistics for investigation and analysis, social sciences for multiple uses, and engineering for exposure assessment. it is a discipline that is now commonly used in research and practices of biological sciences, public health, and clinical research (porta ) . in epidemiology, there are a variety of research studies that stretch from outbreak investigation to clinical trials, covering a range of analytical, scientific, and comparative studies that investigate the cause and spread of disease, analyse the pattern and progress, as well as control and guidelines to support information dissemination, knowledge share, and decision making processes. the world health organisation (who) (who webpage, on environmental health in emergencies, sub-section 'disease outbreaks' a) define outbreak diseases as the ones usually: "…causes by an infection, transmitted through person-to-person contact, animal-to-person contact, or from the environment or other media. outbreaks may also occur following exposure to chemicals or to radioactive materials". while there is an immediate need to investigate the actual cause or source of an outbreak, the investigation can take a long time, and often result in the development of potential scenarios, hypothesis, or continuing scientific research. who (ibid) also categorises the outbreak events into three distinct categories of: ( ) communicable disease outbreaks, ( ) disease outbreak events caused by chemicals, and ( ) disease outbreaks of unknown etiology. the first category generally includes particular environmental factors as the main source of the outbreak, this can be caused by humans, but the source itself comes from the environmental factors influencing the spread of disease; such as from air quality, food, water, and sanitation as four common examples. the second category occurs less frequently and is mostly due to exposure to chemicals or toxins in a particular area. the third category occurs more regularly around the globe, and usually the cause if not clear from inception and it may remain undetected for a while. this category is the focus of this book, through which we try to address resilience and management measures to overcome the urban challenges and diverse disruptions of disease outbreak events. one factor to note is that there are different ways of dealing with different outbreak events, e.g. there are differences between different categories (i.e. shown in the above three categories) and our responses to them, clear differences between natural disasters and disease outbreaks (alwidyan et al. ) , as well as differences between different stages of a particular event (see chap. ). some studies refer to disease outbreaks as disaster scenarios (sandi and kangbai ) or include them in the same category ). however, even though there are some overlapping factors and measures between the two, the author suggests refraining from categorising outbreak events as disaster events or scenarios. the rationale behind this is due to the apparent differences in the nature, progression, and multi-stage characteristics of outbreak events. also, not only that disease outbreak events are different themselves, but some of them may be defined differently at different times and in different contexts, such as the reoccurring case of dengue disease outbreak (brady et al. ) . nevertheless, the stages of disease outbreaks are very similar in how they develop over a period, and only differ in terms of how they can progress, spread, and eventually become contained. in each event, the city resilience and management measures and methods are not the same, but they are generally similar in terms of how we should respond to the impacts and vulnerabilities caused by the situation. in addition, disease outbreaks are different in scale and have patterns of occurrence, recognised as 'epidemic', 'pandemic', and 'endemic' situations. these are different to the general outbreak categories of 'common source' (both continuous source and point source), 'propagated' that is generally transmitted between person to person, 'behavioural risk related', and 'zoonotic' that is normally transmitted from animals to humans (extracted from 'glossary of epidemiology terms'). there are common misunderstandings between these patterns of occurrence, and some research studies confuse one with another. each of these categories represents a different stage at different scales of a disease spread. in most cases of outbreak events, there exists a later or immediate epidemic situation; hence, it is usually regarded as an 'epidemic disease outbreak'. if the spread is contained in just one location, then it can be regarded as just a disease outbreak. however, as this is generally unlikely, it is often regarded as an 'epidemic outbreak'. this is a common case as the spread can occur only in a few days and can easily go beyond the boundaries of a particular region. in most cases, this is almost inevitable as we frequently commute and mobilise, and as we are constantly in contact with multiple groups of people who do the same, too. this cycle of mobility provides an opportunity to increase the probabilities of disease spread or transmission and helps to transfer it from one location to another in a blink of an eye. on the other hand, green et al. ( ) acknowledge the distinction between the two terms, namely "outbreak" and "epidemic", and argue that the difference is indeed related to the size of the event, referring in particular to the scale a disease eventually spreads. in this regard, an epidemic situation is defined as the further expansion of the outbreak event, normally including a larger number of cities and communities, beyond just a particular contained region. this is very common for novel diseases. also as brady et al. ( ) conclude in their studies, there is still scope to understand a practical definition of an outbreak event; one that is unconventional, holistic, and clear. the case of pandemic becomes more momentous as the spread becomes a nearglobal or global situation, meaning that it includes not only multiple regions but also multiple countries across the globe. the actual occurrence of a pandemic event mainly depends on how fast and how efficient an epidemic event is managed. in some cases, a pandemic can last for a much longer period (such as hiv aids pandemic, recognised from onwards). in reality, it can last until it is completely cured. finally, endemic is defined as an infection spread that is "constantly maintained at a baseline level in a particular geographic area without external inputs" (extracted from 'centre of disease control and prevention (cdc)' webpage, division of scientific education and professional development (dsepd) ). this is not necessarily defined as an event but is recognised as a continuing situation of the disease spread. henceforth, we mainly use the terms 'outbreak' or 'outbreak event', as we focus mostly on the defined scale of the city. this book addresses this scale as it requires further attention from the perspective of resilience and management, two factors that will be assessed and discussed throughout. however, the suggestions are common for both epidemic and pandemic situations, but more closely to a more common case of 'epidemic'; an outbreak event that we can say is not completely disastrous but is exceedingly impactful on the societies. before reaching the "vaccine effectiveness period" (pezzoti et al. ) , the city and its communities suffer from the invasive disease outbreak. in a situation like this, cities are more vulnerable. in a common scenario, the situation is always unexpected; hence, preparedness is not exactly adequate to respond to earlier stages of the outbreak and is not as prompt as it should be. in the first few days, or even in the first few weeks of the outbreak, the situation appears to be uncertain and difficult to handle. this is mainly because of the outbreak changes drastically, the broad-spectrum life patterns change in a sudden, and our daily routines and operations become completely disrupted. the multiplicity of impacts is sensed across multiple sectors, affecting the most: our society. while the long term vulnerabilities can be reduced in a more progressive way (lim et al. ) , the short term treatments may take longer than initially expected. as suggested by brady et al. ( ) with appropriate and timely control, the disease outbreak burden can be minimised. yet, this requires preparedness as early as possible and it requires ready-made planning to reduce the city's vulnerability in crucial areas/factors, wherein need the most. as addressed by other studies, fluctuations in case numbers and regular surges can frequently disrupt and slow down the progress of treatment and containment (ibid), which can drive "already-stretched healthcare resources to breaking point" (also see hay et al. a; hay et al. b , garg et al. , cotter et al. brady et al. ) . more importantly, the city's vulnerability increases as the spread continue to affect the primary services and systems of the city, such as healthcare, food systems, transportation services, etc. in general, disease outbreaks are usually fast-developing situations with indeterminate progress and constantly changing updates. these effects or factors put pressure on the society as much as they cause an excessively "high burden due to the lack of response capabilities" (garg et al. , grais et al. , najera , who ebola response team brady et al. ) . also, there is an urgent need to reduce vulnerabilities, by enhancing emergency risk management for health, which is believed to be multi-sectoral (emergency risk management for health fact sheets , p. ), including: this includes a range of factors for individuals, larger groups of people populations, infrastructure, services, and other community factors. in this regard, the need for primary health care at multiple levels is essential to reduce any "underlying vulnerability, protect health facilities and services, and scale-up the response to meet the wide-ranging health needs" (ibid). hence, during an outbreak event, as the city becomes more vulnerable, we should ensure that supporting measures and the role of urban resilience is not reduced. to name a few, for instance, we have patients with other health issues who require attention, we have the elderly whom are more vulnerable than the others, we consistently need essential daily supplies and services, such as food, water, energy, etc., as well as other factors that should be taken into full consideration. therefore, we cannot just avoid all those dynamism or else it cannot last long for a city to fall apart. in the outbreak events, the vulnerability of the city goes beyond just vulnerable communities. the situation is dissimilar to those examples that only target a particular group. hence, outbreak events are usually widespread. this is also one of the reasons why outbreaks are different from those examples of disasters and are instead more related to health emergency conditions (examples by who ). generally, in the outbreak events, cities and communities with weak(er) or no institutional structure suffer the most. for the case of the covid- pandemic, this was evident from inception. this was tracked from the earlier records and updates from who ( b): "the international community has asked for us$ million to help protect states with weaker health systems as part of its strategic preparedness and response plan". the numbers were later increased and included more countries and regions. two months after, the united nations requested for a total of us$ billion cash contributions for nations that will struggle to contain the outbreak. those countries/regions that are not well prepared are likely to experience a shock before they could cope with the unexpected situation. municipal actions, from managerial and decision-making bodies, try to assess the situation as any response is sensitive and require careful processing and monitory. society gets the biggest hit as they experience panic attacks, anxiety, and uncertain conditions. in such events, our voracious nature vivacities as we are alarmed to prepare for survival. in general, people often rush to store more necessary food and supplies, and create a self-imbalance in the equilibrium of regular production and production trends. we do not buy what we need; but instead, we buy what we need and what we think we may need. this is caused by the uncertain circumstances that can change in any direction at any time. the vulnerability does not end there, and becomes more severe if the society is not reassured (schoch-spana et al. ) , and if immediate measures are not in place. hence, there are major debates around society management challenges during outbreak events, such as community/public engagement processes (biehler et al. ; jamrozik et al. ) , public information policies (maxwell ) , health and risk communication (miller ) , community values (schoch-spana et al. ), public health ethics (kenny et al. ; lee ; marckmann et al. , spike , etc. in addition, an extended communication plan is required to effectively respond to those societal needs to ensure vulnerabilities are minimised at multiple stages and throughout the outbreak event. furthermore, the contagious disease could affect many people directly and indirectly, and this potentially increases the vulnerability of society from multiple dimensions (american psychological association ), more than just the disease itself: "the threats to psychological well-being that outbreak pose often can be overcome with the skills of resilience, which can serve as a kind of emotional vaccine. we all can develop resilience. it involves behaviours, thoughts, and actions that can be learned over time". therefore, as a response to vulnerability increase, there is a major need to increase and maintain the urban resilience measures; those interventions that boost the city's management, and those strategies that eventually save the city from a looming disaster. there is more to urban resilience in the disease outbreak events than just a typical example of a resilient city strategic plan. as discussed earlier, outbreak events are inimitable situations; and indeed, they require exclusive responses, too. this was evident from the time when we developed the first resilient city toolkit several years ago (siemens, arup, and rpa ) . through a variety of studies on resilient cities and urban resilience measures, we can verify a range of direct impacts on health, emergency medical services, communities, infrastructure, economy and businesses, profitability, production systems, social well-being, and quality of life. as many foundations of the city deteriorate at a rapid pace, we have to ensure the city is prepared enough to handle the situation before making progress. more recent published books on urban resilience planning are mostly related to natural disasters (to name a few: clarke and dercon ; sanderson et al. ; lamond et al. ; baldwin and king ; miyata et al. ) that address factors of preparedness, resilience, responses, and action plans; those that then respond to immediate, gradual, and long-term transformations. there are fewer examples that include disease and contagion as part of those resilience planning (rodin ; jones ; yang ; singh et al. ; yang chan and shaw ) , which include a range of measures for risk management or bring together related reflections and initiatives (burayidi et al. ) . hence, in order to be effective in practice, urban resilience needs pioneering state-of-the-art thinking. in addition to this, the need for supporting guidelines (ihekweazu, et al. ) and frameworks are certainly essential, too. as our cities grow more in numbers and size, and as they face more adversities and challenges (from the webpage of resilient cities ), we may not always be ready to mitigate particular events; sometimes, we have to adapt, and often we have to enhance what we may have or develop what we may not have (cheshmehzangi ; cheshmehzangi and dawodu ) . in this regard, we need to develop a set of strategies to combat those particular events that can cause significant disruptions or could progressively jeopardise our cities and societies. urban resilience measures are ever needed to respond to those adversities and challenges, those we foresee and not foresee. an outbreak event is one of those examples of specific events, which can be damaging in multiple ways and can increase the burden on the overall city management. in such incidences, the vulnerabilities are extensive and affect the multiple operations of cities. the situation of an outbreak event of any kind suggests an insalubrious city status; it is unhealthy for the government, governance, institutions, economy, health, and on top of all, the society. to date, there is little literature or specific research associated with urban resilience in outbreak events. on the other hand, there are generic examples of practical measures, frameworks, tools, and guidelines that enable us to support those cities in need. yet, in real practice, the city authorities often require to make decisions fast and precisely. those decisions need to be context-specific and should address cultural factors, social needs, and economic concerns of that specific place/city. the process is so fierce that it can cause significant disruptions in any direction. any decision needs to be carefully crafted before it is released to the public, or else it can turn into playful games of multiple means of the media, from social media to a more monstrous international media. they can generate false news, increase anxiety and fear, and they can simply make a pandemonium. in the outbreak events, there are many issues associated with the overarching public health factors that require a new (or revised) perspective; hence, vulnerabilities are at a much higher rate when outbreak events hit the city and its communities. undoubtedly, resilience is needed for any occasion for any community. more importantly, we also need to acquire those resilience skills, both individually and collectively as part of society. the probabilities of failures or failed occasions are high, and reversing them can take longer and interrupt the progress of containment and recovery at any time. any minimal disruption is perceived as a major issue, and the impacts are felt event much greater. many sectors come into an absolute halt, even if temporary, but they suffer significantly. they usually look forward to novel solutions, innovations, and findings in medical research-in other words, something that can save the situation sooner than later. in general, urban resilience must be realised as the backbone of how cities can be managed, both effectively and efficiently, especially during the outbreak events. there are only a handful of preparedness (i.e. including but not limited to services, supplies, and facilities) that can be in place before the actual start of the outbreak; hence, the majority of the work is not necessarily related to preparedness but is indeed the immediate and strategic responses that should develop, shape and get implemented during the event itself. this is exactly why, similar to some of those disaster events, vulnerabilities are high and cities and communities are at a highrisk level. in their report, who ( , p. ) suggest that while the "leadership in managing infectious risks and responding to outbreaks is clear, the health sector also has a critical role in preventing and minimizing the health consequences of emergencies due to natural, technological and societal hazards". in addition to this statement, it is important to note that from the city management perspective, multiple sectors must experience similar-if not the same-situation. other sectors associated with such incidents aim to promptly deal with emergencies and meritoriously cope with the disruptions caused by the event. in other words, the city as a whole becomes a new entity that requires to deal with emergencies at multiple levels and in multiple sectors. by having a resilience plan (i.e. in any practice-based or practical form), the city can work more effectively in managing the event and its negative impacts on the society. hence, it is suggested to enhance the city's resilience where we can and where it seems feasible to do so in the specific context (i.e. in terms of capacity, capabilities, economic background, social issues, etc.). with such a planning approach, we can speed up the containment and recovery processes of the outbreak-i.e. to better contain the spread of disease, and avoid the event to evolve from an emergency status into a disaster situation. finally, what has to be addressed is the way we prepare and respond in a process. this requires a framework that could reflect on the ever-changing situation(s) of outbreak events, which will be addressed in later chapters in more detail (see chaps. and ). therefore, there is an essential need to act reflectively and responsibly by multiple actors of the government (of multiple departments), emergency units and emergency medical and health services, and other associated stakeholders of the public sector, private organsiations, non-governmental organisations (ngos), community organisation groups, and the general public. in reality, the situation creates a new ecosystem of management and operations, one that requires to have resilience measures and adaptive capabilities. in their report on 'communicable diseases following natural disasters', who ( ) proposed a set of risk assessment and priority interventions, to ensure the needs of the society are addressed promptly throughout the events and adequate planning is operational for both therapeutic and preventive interventions. these factors, apart from having adequate planning measures, requires a tangible resilience capacity in order to reflect quickly, be ready, and respond to those situations in the best possible way. these would be the concluding remarks of this introduction chapter in the following section. as an introduction to the book, this chapter has summarised a general overview of outbreak events, and how they are progressively more important in the fields of 'urban resilience' and 'city management'. the aim of this book is then to see how we can save the city before it becomes too vulnerable, and how we can respond to those unexpected and unfortunate events that could cost us many human lives and many other pressures. in a way, the analysis so far indicates that the extent to which we see outbreak events in a city boundary needs more scholarly attention. as mentioned earlier, there are many cases of outbreak events that we do not even hear about; as we only learn about the ones of the global importance or higher contagious nature. some are only become more visible because of their political importance, or the economic impacts they may have at the much larger global scale (such as the recent covid- outbreak). yet, as it appears from the recorded data of global outbreak events (who ), it is indicated that we constantly deal with various outbreak events in communities all around the globe. how we may reflect on those events are something that we should take into full consideration for better future preparedness and a much-enhanced resilience ( fig. . ) . it only makes a logical sense that we should plan this ahead and not wait for the unforeseen impacts. as we continue to neglect the importance of outbreak events, we may continue to neglect the importance of resilience measures we should develop for our cities and communities around the world. this is not a simple task, but without a doubt, it is one very important task that can save the lives of many people who could live if we take action either in advance or as early as possible. so far, we highlighted the basic knowledge, the existing literature on outbreak events, and the perspectives that refer to the situation of a typical outbreak event. we learned outbreak events are not universal; as they differ from one disease to another, and from one context to another. we realised the same disease can also be different fig. . the three primary r's in the practice of urban resilience. source the author's own from one location to another. our cities are also very different, with primary differences in how they operate, their size, infrastructure, capabilities, economic conditions, social values, services, networks, etc. therefore, our cities and communities would certainly reflect on outbreak events very differently, too. this means their readiness will be different, and how they may respond will ultimately be different. however, certain commonalities cannot be simply avoided in case of an outbreak event. for instance, the commonalities are mostly related to those institutional and societal needs, meaning how we plan to keep up the operations of our systems and services, how we may provide access to clean water, daily food supplies, energy, hygiene, amenities, and how our emergency units are supported and enhanced, as well as many other factors. in sum, cities, although different in many ways, will face similar difficulties/challenges in the case of outbreak events. careful and comprehensive planning cannot be anything less than an assurance to overcome those difficulties that can simply threaten any community that exists in our world. in reality, we have to understand there is no immune community; at least, there is none that we know about. the next few chapters of the book focus purely on key factors of urban resilience and city management to address their practicalities in a probable case of an outbreak event. henceforth, the book addresses methods and strategies to enhance urban resilience during outbreak events. these ideas are generated through existing literature, practices, available tools and frameworks, dialogues with multiple experts of different disciplines, continuous discussions with local governmental authorities and global organisations, and the invaluable experience gained from standing with the community in a particular pandemic outbreak event. resilient cities webpage responding to natural disasters 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framework for analysis and action to build community resilience protecting historic coastal cities: case studies in resilience (gulf coast books) meningococcal c conjugate vaccine effectiveness before and during an outbreak of invasive meningococcal disease due to neisseria meningitidis serogroup c/cc a dictionary of epidemiology the resilience dividend: managing disruption, avoiding disaster, and growing stronger in an unpredictable world design for urban disaster: response. resiience and transformation disaster management and the west african ebola outbreak urban disasters and resilience in asia vector control in zika-affected communities: local views on community engagement and public health ethics during outbreaks toolkit for resilient cities: infrastructure, technology and urban planning, pages document urban health risk and resilience in asian cities (advances in geographical and environmental sciences) principles for public health ethics the social roots of risk: producing disasters, promoting resilience (high reliability and crisis management) ebola virus disease in west africa-the first months of the epidemic and forward projections communicable diseases following natural disasters: risk assessment and priority interventions health emergency and disaster risk management framework webpage source on the category of 'environmental health in emergencies', sub-section 'disease outbreaks rolling updates on coronavirus disease (covid- ), as part of updates on march : who characterizes covid- as a pandemic public health and disasters: health emergency and disaster risk management in asia (disaster risk reduction) early warning for infectious disease outbreak: theory and practice key: cord- -vhznzg x authors: kimari, wangui title: outlaw nairobi versus the pandemics date: - - journal: city soc (wash) doi: . /ciso. sha: doc_id: cord_uid: vhznzg x nan poverty and the lack of sufficient critical care units and ventilators), activists point to another "pandemic" that has impacted kenyans more than covid- during this time --the government, and in particular the nairobi metropolitan services (nms) who coercively took over the county of nairobi on february . certainly, even as poor urban residents have to fight both "pandemics," at this time, the city's administration is proving to be a much more dangerous disease. in the first three weeks of may, two months into the lockdown that has devastated livelihoods for the vast majority of the city, the nairobi metropolitan services evicted close to households --destroyed homes with no compensation or alternative accommodation provided --in the parts of nairobi that in my own work i call "outlaw spaces." these are areas, usually in eastlands -the east of the city, which have been, through an intentional colonial urban governance, been made outlaws in two senses: they are intentionally pushed outside of the law since they are not habitually privy to the most basic rights enshrined in the constitution, and are outlawed -consistently criminalized. the longue durée colonial urban planning processes of nairobi have therefore ensured that residents of these outlaw spaces can be evicted at whim --without prior notice or adequate if any compensation --and their spaces deprived of basic provisions such as water and sanitation services. this consistent and formal marginalization is also connected to an over policing and criminalization of residents, ensuring that those who don't have water are the same ones who are being killed by the police; combined sinister processes seemingly established in morphology and (re)producing ecologies of exclusion (kimari ). as the epigraph by a powerful young activist in nairobi that began this article states, the government is currently competing with covid- to see who will "finish kenyans first." currently, many parts of outlaw nairobi are dealing with no water, even at a time when the need to wash hands is particularly imperative. in addition, kenya's version of a mini-lockdown (where work stops but government-sanctioned essential services continue, and movement is contained within the curfew hours of am - pm) is policed so severely that no less than people have been killed for being outside during these hours. victims of these extrajudicial killings include a -year old boy, yasin moyo, who was shot while on his balcony at . pm in the outlaw space of kiamaiko, mathare, and a boda boda rider, a motorcycle taxi operator, who was killed after taking a neighbor to hospital. what's more, scared to leave their homes after pm, pregnant women have died while giving birth without access to maternal health care, and those who find themselves sick at inconvenient times have to suffer through the night before they can get medical assistance. these events are coupled with and exacerbated by the loss of livelihoods for many of those who are % of the city's residents, but who live on only % of the city's surface area. since this demographic survives by engaging in informal day to day labor contracts that can no longer take place because of the lockdown, many households are eating one meal a day. in view of this situation, community organizers in areas like kayole, githurai, dandora and mathare are asking whether the government wants to angamiza corona [get rid of corona] or citizens. these critical demands are made by residents who are embedded in particular spatialized histories that delineate those who are able to "work from home" (and use the g internet google balloons officially launched by the president for this purpose) from themthe majority of the city that lives in small and often impermanent dwellings. certainly, these claims can be cartographically overlaid onto geographies that were never meant to exist. before nairobi became nairobi, the aspiring colonial and then postcolonial "green city in the sun," and was enkare nyrobi --the place of cool waters, it was a site within a complex of rivers that provided a meeting and trading place for a number of neighbouring ethnic groups. following the notorious berlin conference of - , where european countries divided the continent commensurate to one's power (and ego), this geography with its situated socio-ecological practices became further embroiled in the machinations of racial capitalism; in , with its new status in a british declared "east african protectorate," it became a mid-point railway centre between kenya and uganda. its founding as a railway agglomeration, a node in the business of transporting goods enabled by imperial 'trade' from uganda to england and beyond, also functioned to demarcate distinct racialized zones in this nascent city. and these initial racial imprints would have salience long after kenya's independence. this original zoning saw whites harboured on the dryer, cooler and elevated grounds that were free of malaria and offered vantage points for surveillance (basically, the setting for the film out of africa). south-asian descendants, brought over to build the railway under torturous conditions at the end of the c th, would be settled in the lower and less green sections of town, effectively the buffer between whites and blacks. africans, who were not formally allowed to live in the city until the end of the second world war (they were only meant to be here if they had a job, and african women were not meant to live in the city at all --they could only be imagined as the biocultural vectors of african life in rural areas) were informally recognized in the "twilight" areas of town that were established in low-lying malaria prone flood plains (otiso ; hake ; white ) . at independence, these parts that were formerly the native city, fanon's cite indigene, and governed by the racialized formal and informal dictates of the colony, would continue to be offered none and barely, if any, services. the stain and stigma that derived from colonial urban governance actions --an assemblage of social, economic, political and ecological practices and ideas-would linger, even as the 'post-colonial' city is said to have replaced race with class in determining who could live where (owuor and mbatia ; hake ; kimari ) now, according to some foreign observers, it is the capital of the "silicon savannah," a moniker referencing kenya's position as a technological hub, primarily due to m-pesa, a mobile money transfer service, and the abundance of technology driven social enterprises that have sprung up everywhere. it is this kind of acclaim that, according to a recent cnn article, makes nairobi "the fastest city on the planet" a "thriving metropolis" that is the only "city with a safari park on its while there is pride for the city, and feelings of home, most residents also consider nairobi a mélange of life and livelihoods patched together through various alliances of struggle and determination, and, somehow, still, holding on. the people of nairobi, have, however, a way of defying the most hopeless situations by adopting simple yet unorthodox expedients and outlaw nairobi must, definitely, try and hold on. writing about its former native city over forty years ago, hake ( ) detailed a space that despite the evictions and neglect by the city administration was determined to survive. it was, he called it, the self-help citya geography of mutual aid, among selves, that was necessary in view of its abandonment by the state. currently, as both pandemics persist --covid- and the colonial urban governance regime of the nairobi metropolitan services, residents of nairobi's poor settlements are making demands and finding collaborative ways to "self-help" each other. since not wearing a mask in public can now attract a fine of kes , [$ ], local organizations are coming together to mass produce these masks, and share them with the most vulnerable, the elderly, differently-abled, sick and young. in addition, those who have been evicted and sleeping out in the rain are the recipients of small but consistent solidarities from their neighbors and broader city residents. domestic workers who have been locked out of neighborhoods like eastleigh, since it is seen as a coronavirus hotspot, are bribing the policemen manning the roadblocks at the entrances and exits of these now enclosed neighborhoods, so that they can get in and wash clothes or clean houses for kenya shillings [$ ]. these monies, less than the daily minimum wage, will allow them to purchase food and necessities for the day. at the same time, artists are using graffiti to imprint coronavirus messages on tenement walls to help citizens remember to keep safe, and community-led groups, most recently in kayole, are simultaneously protesting at the local office of the nairobi city water and sewerage company to demand clean, safe and affordable water, and finding ways to provide free hand washing stations wherever possible in their neighborhoods. and as poor urban residents continue to demand dignity, the right to life and basic services, they prove hake's observation from sixty years ago: "the people of nairobi, have, however, a way of defying the most hopeless situations by adopting simple yet unorthodox expedients." indeed, even if they are fighting not one but two pandemics, outlaw nairobi will survive. figure : picture of justice center activists after they were released from a police station following their detention for organizing a protest at the local division of the nairobi city water and sewerage company. picture credit: maryanne kasina african metropolis: nairobi's self-help city the story of a pump: life, death and afterlives within an urban planning of "divide and rule post-independence development of nairobi city, kenya. paper presented at workshop on african capital cities organised by codesria the problem with predicting coronavirus apocalypse in africa colonial urbanisation and urban management in kenya nairobi: the fastest city on the planet the comforts of home: prostitution in colonial nairobi key: cord- - wavi tk authors: nazarimehr, fahimeh; pham, viet-thanh; kapitaniak, tomasz title: prediction of bifurcations by varying critical parameters of covid- date: - - journal: nonlinear dyn doi: . /s - - - sha: doc_id: cord_uid: wavi tk coronavirus disease is a recent strong challenge for the world. in this paper, an epidemiology model is investigated as a model for the development of covid- . the propagation of covid- through various sub-groups of society is studied. some critical parameters, such as the background of mortality without considering the disease state and the speed of moving people from infected to resistance, affect the conditions of society. in this paper, early warning indicators are used to predict the bifurcation points in the system. in the interaction of various sub-groups of society, each sub-group can have various parameters. six cases of the sub-groups interactions are studied. by coupling these sub-groups, various dynamics of the whole society are investigated. predicting bifurcation points of the dynamical disease are important [ , ] . many types of research have been done to predict the bifurcation points of biological systems [ , ] . there are some evidences that near the bifurcation points of a dynamical system, the dynamic becomes slower. it means the system needs more time to pass the transients and reach its final state [ ] . various methods have been used in the prediction of bifurcation points. some of the wellknown indicators are autocorrelation at lag- and variance [ ] . they bear some issues in predicting bifurcations in more complex dynamics. recently, a new method has been introduced to improve the conventional indicators [ ] . lyapunov exponent is another interesting predictor of bifurcation points [ , ] . the study of networks of systems can help to understand the collective behavior of systems. complex networks have a great impact on human life [ ] . they have many components which are interacting with various connections [ , ] . synchronization is one of the most interesting properties in the dynamics of networks [ , ] . many biological systems, such as neurons, do their task in a network [ , ] . many studies have been done on networks [ , ] . a chaotic model of epilepsy based on the neural network was proposed in [ ] . various dynamics of a multilayer network was discussed in [ ] . in this paper, various dynamics of the seir system, as a model for the development of covid- , are investigated. bifurcation diagrams of the system are studied to show its various behaviors by changing parameters. bifurcation points of the system are discussed, and they are predicted using autocorrelation. also, the interaction of five cities is studied with various connections and parameters to show the effect of traveling in the outbreak of the disease. in this paper, the seir model is used as a model for the development of covid- . it is a compartmental model of infectious disease and its epidemic outbreak [ ] . it contains four classes of people as susceptible (s), exposed (e), infected (i), and resistant (r). the seir model is as follows: in this model s, e, i, r are the number of susceptible, exposes, infected, and resistant people. parameters l; b; m; r; c are the background of mortality without considering the disease state, the speed of moving people from susceptible to exposed, the vaccination rate, the speed of moving people from exposed to infected, and the speed of moving people from infected to resistance. it should be noted that the vaccination causes people to move from a susceptible group to the resistant one directly. to study the dynamical properties of the model, various bifurcations are investigated. part (a) of fig. shows the bifurcations of model ( ) by changing the parameter of the background of mortality without considering the disease state. it should be considered that in each parameter, the variables approach to an equilibrium point by passing enough time. the bifurcation diagram is plotted with the forwarding continuation method. dynamics of the system have various bifurcation points. to predict bifurcation points of the model, autocorrelation (ac) is used. the absolute value of autocorrelation determines the slowness of dynamics by approaching to ''one'' near the bifurcation points. autocorrelation is calculated from the time series of susceptible, exposed, infected, fig. . it can be seen that the ac approaches one in bifurcation points l ¼ : and l ¼ : . also, the population of exposed and infected people has a change of concavity in approximately l ¼ : , and the ac can predict this bifurcation. the ac of the resistant population is fixed to one in l [ : because of a computational error. there are not any transients in the time series of l [ : with a forward continuation method. the speed of moving people from infected to resistance is another parameter that is investigated in the following. figure shows the bifurcation diagram of model ( ) concerning changing parameter c. in part (a) of that figure, bifurcation diagram of four variables of model ( ) by changing parameter c is plotted. to have a better view of the three smaller variables, their zoomed view is shown in part (b). ac is used to predict the bifurcation points of the population variables as part (c). ac predicts bifurcation point in c ¼ : and also shows a small peak in the change of concavity of resistant population. predicting these bifurcation points can help the world from being surprised by variations of covid- epidemic states. in this section, the connections of five cities are considered to show the effect of intercity traffic restrictions. to reach this goal, system ( ) is considered as the model of development of covid- in each city. then, the five cities are connected in a watts-strogatz network [ , ] . the connection graph is shown in fig. . so, each of the four variables of system ( ) is connected to the variables of other cities as eq. . x i is the state variables of each city, and f is their functions. the nodes are connected by coupling matrix c, and k is the strength of coupling. an undirected network is used. so, we consider if the coupling between node a and node b is one, it means that people can travel from city a to b and vice versa. now, various cases are studied. the initial values of variables are set constant as table . in the first case, we consider that no people can travel from one city to another one (k ¼ ). parameters fig. . the results show that each city has its own evolution, and they have no effect on each other. the number of exposed and infected people approaches zero by passing the time, and the number of susceptible and resistant people becomes constant but different for each city. in the second case, the cities are considered to have some connections to each other (k ¼ : ). parameters are set constant for all five cities as ðl; b; m; r; cÞ ¼ ð : ; : ; : ; : ; : Þ. the results which are shown in fig. present that this small connection makes all the cities become the same in the evolution of covid- . however, their approaches to the same value are slow. in the third case, the cities are considered to have more significant connections to each other (k ¼ : ). parameters are set constant for all five cities as ðl; b; m; r; cÞ ¼ ð : ; : ; : ; : ; : Þ. the results of this network are shown in fig. . in a comparison of this network with the previous one, the current network is faster in approaching their same constant values. in other words, by passing enough time, the five cities become synchronized. in the fourth case, the cities are considered to have some connections to each other (k ¼ : ). in the study of a single system, the results show that parameter l can change the dynamic of the evolution of covid- . parameters of the network are set constant for all five cities as ðl; b; m ; r; cÞ ¼ ð : ; : ; : ; : ; : Þ in this case. the parameter l is different from the previous network. the results (which are presented in fig. ) show that decreasing the parameter l makes an undershoot in susceptible and resistant population. also, the lower l parameter makes the susceptible population constant to a lower number and resistant population to a higher number. to have a more realistic viewpoint, the parameters of cities are considered to be different. in the next two cases, parameters for each city are considered as, in the fifth case, the cities with various parameters are considered to have some connections to each other (k ¼ : ). the results of fig. show that in the case with various parameters for each city, the population of the susceptible and resistant group in the cities cannot be synchronized, and they are different in all the times. however, the population of exposed and infected people approaches to zero in all the cities. also, the lower l parameter makes the susceptible population constant to a lower number and resistant population to a higher number in the sixth case, the cities with various parameters are considered to have more connections to each other (k ¼ ). in other words, the coupling strength is increased to reveal the parameter in which the dynamics of various cities become synchronized. the results of the network are shown in fig. . it shows that the population of exposed and infected people in all cities approaches zero by passing the time. the population of susceptible and resistant people of various cities is approximately synchronized; however, the zoomed view of the susceptible population shows they are not completely synchronized. so, in cities with the same parameters, increasing the coupling strength causes the dynamics of five cities to become the same by passing enough time. however, in cities with various parameters, reaching the same dynamics needs a much bigger coupling strength. also, decreasing parameter l changes the dynamics of covid- outbreak. in this paper, the seir model was used as the model for the development of covid- outbreak. in the first step of this study, various bifurcations of the model by changing some critical parameters such as the background of mortality without considering the disease state and the speed of moving people from fig. variations of state variables of five cities with different parameters for cities and coupling strength k ¼ : ; the population of the susceptible and resistant group in the cities cannot be synchronized, and they are different in all the times. however, the population of exposed and infected people approaches to zero in all the cities infected to resistance were discussed. then, autocorrelation was used to predict bifurcation points of the model. to visualize the collective behavior of covid- by the effect of traveling between various cities, a network consisting of five cities was studied. the effect of various parameters and the coupling strength between cities was discussed. watts-strogatz network was used to simulate the connection of five cities. in the interaction of various cities, each city can have various parameters. by coupling these cities, various dynamics of the whole society were investigated. six cases were defined to study various cases of cities interactions. the results showed that in cities with the same parameters, by increasing the coupling strength from zero, the dynamics of five cities become the same by passing enough time. however, in cities with various parameters, the same dynamics cannot be reached very quickly, and it needs a much bigger coupling strength. also, the results showed that decreasing the parameter l can change the dynamics of covid- outbreak in cases with the same parameters for five cities. an interactive web-based dashboard to track covid- in real time covid- and italy: what next? insights from early mathematical models of -ncov acute respiratory disease (covid- ) dynamics a theoretical study on modeling the respiratory tract with ladder networks by means of 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synapse-modulated dynamical properties of coupled neurons under magnetic flow a review for dynamics in neuron and neuronal network emergence of synchronization in multiplex networks of mobile rössler oscillators synchronization in networks of initially independent dynamical systems modeling of epilepsy based on chaotic artificial neural network chimera states in a multilayer network of coupled and uncoupled neurons collective dynamics of 'smallworld' networks explosive synchronization of complex networks with different chaotic oscillators conflict of interest the authors declare no conflict of interest.open access this article is licensed under a creative commons attribution . international license, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the creative commons licence, and indicate if changes were made. the images or other third party material in this article are included in the article's creative commons licence, unless indicated otherwise in a credit line to the material. if material is not included in the article's creative commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. to view a copy of this licence, visit http://creativecommons.org/licenses/by/ . /. key: cord- -jg u qc authors: degarmo, mark b. title: activating embodied imagination during covid- : a performative reflexive autoethnography date: - - journal: qual inq doi: . / sha: doc_id: cord_uid: jg u qc embodied imagination is a learning theory that reverses the accepted western “think first, then act” learning sequence though movement improvisation followed by reflection and reflective methods across verbal and nonverbal, including embodied-kinesthetic, modalities. healing the cartesian divide might have positive effects on world cultures and people across socioeconomic strata, especially urgent during the covid- pandemic as multiple disruptions to daily life have quickly increased uncertainty and stress, compromising health and well-being, especially of traditionally marginalized excluded people of color. expanding the performative reflexive autoethnographic project through embodied imagination broadens and deepens this global, transcultural, transdisciplinary effort through the human body, traditionally not considered human thinking’s locus. benefits across global societies include greater self-care, the ability to act effectively quickly in response to a world with exponentially increasing complexity, and awareness that creativity is a global communitarian human birthright, not a rarity relegated to exceptional people. every day i'm faced with my latest daily failures. i feel like a fifth grader special needs boy held back in third grade with total dyslexia-techno-phobia unable to read the screen, perceive the meaning of the computer icons, unable to translate from the new, improved visual world to my body, my embodied-analogway-of-knowing, understanding, doing, and sense-making from my senses, not bill gates' genius, from my stupidity. i wake to feel myself a total failure for weeks now in virtual lock-down hell. encased in amber, a relic from the recent analog-past and born in the th century. i am a child left-behind with no chance for mourning, no gatherings, not a single touch. virtual glances, virtual distancing. i feel lost, blinded, blindsided by today's world. (degarmo, a) therefore, awareness is growing, albeit slowly and without consensus, among the white geographically dispersed general public that u.s. genocide and slavery built the country's and possibly their own wealth, and never ended with treaties and abolition. these massive legacies continue to inform, pollute, and undermine u.s. social, educational, political, economic, housing, healthcare, and police funding and enforcement policies and practices. meanwhile, during the past months, march to july , on the microscopic level, there quickly emerged an urgent need for self-care and self-protection in national, regional, and local environments displaying rapidly increasing polarization and disruption of public and communitarian discourses. a newly charged public posturing materialized, grounded in confrontation rather than expression of alternative views with hopes of creating synthesis and new shared understandings of complexity and complex issues. increased stress levels across multiple complex toxic factors impacted ways of daily living and doing business, resulting in increased mental illness, domestic violence, and self-inflicted harm. many students and their families, unable to meet the technical knowledge, equipment, and broadband internet access requirements, did not show up for online learning mandated when schools were abruptly closed. a colleague shared, however, that even mit and harvard were unequipped to pivot quickly to online teaching and learning. global disaster (and i showed up) global disaster . . . and i showed up. for beginning-middle-or-end? my embodiment is existentially threatened. theory appears, but practice calls me. i peer through a visual peephole outwardly and feel through a kinesthetic portal inwardly reflections on aging, death, and dying i am a dancer, choreographer, writer, and researcher, and i launched my dream to "become" a dancer and choreographer as a -year-old about years ago. i have been reflecting on aging, death, and dying during covid- 's sheltering-in-place mandates. embodied imagination, movement improvisation followed by reflection and reflective practice across various verbal and nonverbal modalities, reverses the accepted western understanding of knowledge construction (degarmo, ) . embodied imagination as a learning theory posits that action followed by reflection is the sequence for accessing embodied imagination. through the process of participating in the "massive and microscopic sensemaking" challenge posed by markham and harris ( ) via my performative reflexive autoethnography, i have learned that embodied imagination's implied cycling action always begins again in life. as one ages, however, in the sense of having more experiences to draw upon and stories to tell, particular ways of knowing or working through a topic reflexively might emerge. with aging, embodied imagination is not a tight circling or spiraling. it is a flow of movement whether through air or water with much broader loops, more akin to submerging and surfacing in the water that create a pattern more like an eddy or reverberations of ripples. it is a dance with various incarnations of oneself. an invisible microscopic link to our extinction. the white gods have returned, again, as they did, as prophesied. embodied imagination: movement-improvisationand-reflection feel to be my saving grace, my core, self-care during a first global tsunami, humankind's warning from mother earth to her children. my intersectional identities include founding and running a new york city not-for-profit dance performance organization and developing dance education programs for public schools since the s (corcoran, ) . schools in the united states, starting at the elementary level, teach the accepted u.s. method of "think first," then possibly act, and if so, act judiciously, cautiously, and sometimes apologetically. concurrent with perpetuating western cultural norms inherited from the positing of the cartesian divide, this accepted learning and teaching methodology perpetuates practical and negative everyday consequences. what has reflexively surfaced for me is realizing that i am still investigating whether my personal cartesian divide is healed, or even healing, through my embodied imagination. i have, however, come to recognize that bricolage takes place over time and through stories, as well as, through the complexity of my own embodied imagination learning practice. my experiential inquiry has well begun, if not begun well. disruption of previous patterns of cognition and habitual ways of moving inherited from cultural, educational, familial, and personal experiences, assumptions, and normativity is often an aspiration for the performative improvisational composer and embodied bricoleur, regardless of the degree to which originality or innovation for the individual is possible. embodied imagination offers a methodology to be further developed as part of the expanded bricolage project. it disrupts through self-directed and somatic (i.e., body-based) inquiry and performative research methods, cultural normativity through juxtaposition, multiple perspective-taking, and layering and removing layers. as with other forms of bricolage, one rationale for its research purpose is to uncover or bring to the surface deeper levels of implicit and tacit material through patterns otherwise unperceived, unseen, and unfelt via the kinesthetic and proprioceptive senses. the embodied methodological research bricoleur's attention to "rigour and complexity" includes use of an armature to prepare for activating embodied imagination within an improvisational time-space-energy-relationship continuum in a performative moment. the chinese calligrapher's single-stroke moment of insight grounded in lifelong study and practice is a metaphor for an armature's purpose. my bricolage armature during covid- included throwing open my new york city apartment's windows, as my mother always did mid-winter, march - while trying to mobilize in exodus to my country home hr north; looping the same hike on my road; repeating words and phrases; and swimming to "bypass cognitive" domination and logocentric decision making (cedillos, the complexity that the embodied bricoleur acknowledges and encounters through rigor includes the otherwise invisible yet embedded crystalline structures that refract and reflect the multiple dimensions and levels of the bricoleur's past experiences, emotions, trainings, explorations, injuries, pleasures, and physiological challenges. these crystalline structures are embedded landscapes of the human body's record of one person's life's journey. it is my reflexive "coming to know" over a life span and through remembering. are we at the edge of a black abyss? is this, or worse, how it ends? my embodied bricolage and embodied imagination practices and methods include: preparing, entering, gathering, performing, exiting, and reflecting. one prepares the performative space, enters it with detachment and expectation; gathers the forces one needs, performs the task at hand with the tools required to do so, exits the performance space, returning to pre-performance physical levels, and reflects on the meaning of the cycle. performative reflexive autoethnography, as inquiry approach and theory are new to me (alexander, ; bialostozky judisman, ; holman jones, ; markham, ; soyini madison & hamera, ; spry, ). yet i know them well as a practicing creative artist and performer. constructivist grounded theory provided the emergence from practice to theory of embodied imagination. through this massive and microscopic process, i have learned that the personal stance can inform understanding of the massive forces emerging during covid- . i have experienced a tremendous amount of emotional and physical pain that surfaced through my body over the past months. i realized that the themes of aging, death, and dying while not unknown to a man who has faced a lifetime of trauma have looped back into my sphere of meaning-making through this performative reflexive autoethnography. embodied imagination can play a key role in self-directed learning and healing and in a deeper understanding and appreciation of self and others, including the earth. hopefully, there are ways through (the anxiety, uncertainty, unknowable) by focusing on our bodies and self-care (acknowledging this situatedness is privileged, not universal; yet there are benefits across socioeconomic strata). there are teaching, learning, healing, growing/expanding capacity benefits. some findings are a greater ability to trust the process, be present, find balance by oneself in relative isolation, and ground through the body first (self), to reach out to others, and the larger world (social media, tech), and the earth. where are the beginnings? who am i?" paradoxically inklings surface to consciousness that my life's repeated history of physical and emotional traumas now serves me, strengthens me, reflects the wisdom of the elders, the storytellers, and the dancing fools. my ancestors' presence through my flesh linking molecularly to the stars themselves guides me. micro and macro merging in my bones, flesh, organs, sinews, connective tissues channel performativity. we are one human organism on our planet and embody violence and love. i feel darkness. i see light. these are my ideas. (degarmo, b) • responding rapidly and effectively to quickly changing volatile environments and high degrees of uncertainty; • maintaining physical, emotional, social, and psychological well-being during physical isolation, solitude, and distancing; • achieving greater comfort and confidence exploring and experimenting with new technologies, forms, and ways of interfacing with self, others, and the environment, including performative reflexive autoethnography; • connecting the internal, micro-environmental leadings of direct human experience with experiences of the global digital environment; and • practicing transcultural transdisciplinary problemsolving across multiple levels and dimensions, including issues involving humans, machines, and the planet. my experience knowing embodied imagination's learning sequence supported navigating uncertainties thus far. i found i had to "restart/reboot" (as much as i mistrust using this ict metaphor) my body-mind-spirit-emotions. i am finding my way with greater reassurance only recently, as i started writing this paper, that is, shedding my anxiety and consciously wanting to release, not hold, it. our messy, often segregated and compartmentalized, lived lives just got a whole lot messier in the united states during covid- . as i do in my life's, artistic, and research generative, analytical, and interpretive processes, i created masses of audiotaped, photo/videographed, visual arts, and written materials functioning as performative reflexive autoethnographic field notes, including daily three-page journal entries coded with weekly reflective summaries; work logs/mind maps with visual arts; a poetry chapbook fashioned from a gardening log; assignments from the massive/microscopic global autoethnographic work group; facebook posts, messages, and texts; and new and existing biweekly-alternating and monthly programs broadcast by my new york city dance organization. as a kinesthetic learner; performing artist; professional dancer, choreographer, writer, and researcher; and not-forprofit organizational founder and leader, over these months i also shifted-up my screen-bound stasis through nonverbalkinesthetic inquiry and reflective practices, recognizing my stress and to ground myself. my privileged self-care included a progressive seasonal menu to days a week: forest-bathing/ hiking on a two-mile back ridge, taking an online classical ballet barre, walking a . -mile road loop, and swimming open-water mins in a glacial lake. while i think i know how to clean up well enough (critical when writing grant proposals and funding requests for government, foundation, corporate, and individual donors), my covid- performative spoken-word rants and nonverbal-kinesthetic improvisational-movement compositions erupted suddenly, unexpectedly, messily with emotional feelings: fear, loss, distress, outrage, sadness, despair, and uplift. personal and national histories of "healed and healing" lifelong and intergenerational physical and emotional traumas can surface unexpectedly. i see more clearly now through this performative reflexive autoethnographic process how mine, were laced with our, traumas of suppressed, rewritten, and tragically unacknowledged u.s., hemispheric, and global histories. the author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. the author(s) received no financial support for the research, authorship, and/or publication of this article. mark b. degarmo https://orcid.org/ - - - performance ethnography: the reenacting and inciting of culture el performance como instrumento de protesta arte para la convivencia y educación para la paz bricolage: a perceptual methodology and cognitive bypass model for art-based qualitative inquiry an embodied cognition approach to enhancing reading achievement in new york city public schools: promising evidence. teaching and teacher education accessing embodied imagination: an approach to experiential learning through movement improvisation [doctoral dissertation every day i'm faced global disaster (and i showed up global disaster (and i showed up): a video and installation i start crying underwater i witness the tail winds improvisación performativa transdisciplinaria enseñanza de composición coreográfica desde un enfoque transdisciplinario autoethnography: making the personal political arte para la convivencia y educaciόn para la paz levels of racism: a theoretic framework and a gardener's tale hunting the other (trans. c. a. zito). le monde diplomatique redefining and interpreting the object of study go ugly early": fragmented narrative and bricolage as narrative method massive and microscopic sense-making in the time of covid. call for expressions of interest introduction: performance studies at the intersections performing autoethnography: an embodied methodological praxis universal declaration of human rights united nations declaration on the rights of indigenous peoples mark b. degarmo, dancer, choreographer, writer, and researcher, lives in new york city and the mid-hudson valley. over years, he developed partnerships in literacy through dance & creativity©, an evidence-based embodied cognition interdisciplinary dance arts educational intervention for underresourced and disenfranchised new york city public school students of color in prekindergarten to grade living under the u.s. poverty line. degarmo has led his performing groups on multiple projects across countries. new york city audience members and press responding to his performances reflected: "frightening . . . in a way great art always should be," "a gladiator in various arenas." key: cord- - yvcl q authors: lawrence, roderick j. title: responding to covid- : what’s the problem? date: - - journal: j urban health doi: . /s - - - sha: doc_id: cord_uid: yvcl q this commentary argues that the coronavirus sars-cov- pandemic should be considered as a transdisciplinary societal challenge that requires coordinated systemic thinking and actions in the context of uncertainty. responses to the propagation of the coronavirus sars-cov- and the health, economic and social impacts of covid- are complex, emergent and unpredictable. we describe the virtuous relations between three prerequisite conditions—multilevel governance, knowledge and types of resources and individual and collective behaviours—that should be combined in transdisciplinary responses. first, multi-level governance of this global pandemic is fundamental. at the outset, we challenge political and public scepticism illustrated by the incapacity of politicians and laypeople to listen and learn from scientific knowledge and professional know-how in the context of uncertainty and vulnerability. governance denotes the way that governments, public administrations, private enterprises and community associations interpret the pandemic, and how they decide collectively to respond to it. in order to reduce known unknowns about this beta-type coronavirus with species jump, the coordinated synthesis of interdisciplinary information and knowledge, professional know-how and individual and social perceptions and understandings are necessary. then this broad understanding can be applied to define the appropriate allocation of many types of resources (e.g. administrative, financial, human, material, medical, pharmaceutical and scientific) necessary to implement effective responses (see fig. ). in contrast to south korea and taiwan, many european countries have reacted by following the propagation of this coronavirus rather than being proactive to prevent it despite the warnings made by scientists from [ ] . the contrasting responses of federal/national, state/regional and city/local authorities between and within countries, since january , illustrate how differently this real-world challenge has been interpreted; for example, comparisons between cities in the lombardy and veneto regions in northern italy highlight successes and shortcomings that can be interpreted as lessons learned [ ] . several types of resources coexist for coordinated action and systemic responses to this extraordinary situation: administrative, behavioural, financial, health care, legal and medical resources, and have been used at different geo-political levels, sometimes in an uncoordinated fashion of 'winner takes all'. notably, some actions have been endorsed by the world health organization (e.g. confinement, quarantine, distancing, testing, washing hands) whereas others have not (e.g. wearing masks in public spaces). the diverse interpretations and responses of governments and public administrations confirm that 'evidence-based policy' is a theoretical concept that is often not applied in current circumstances (like many others including ambient air pollution and passive tobacco smoking). notably, some local authorities in american and european cities have not introduced systematic testing and proactive tracing, or legally binding measures, to protect population health. the second prerequisite condition is the importance of specialised data, information, knowledge and professional know-how required to understand and counteract a new virus for which there is still no proven medical or pharmaceutical remedy. the known unknowns about this coronavirus can be identified and studied using principles of one health, ecological public health, and planetary health during transdisciplinary research and practice in community settings to 'collect facts on the ground' beyond the walls of laboratories [ ] . the nonlinear, uncertain and unpredictable characteristics of this coronavirus are derived from the evolving interfaces between natural ecosystems and human-made environments that accommodate people and all other living organisms that may be vectors of zoonoses including this coronavirus. these novel situations, created by rapid urbanisation in cities and mega-urban regions, can be analysed by interdisciplinary case studies of the multiple consequences of rapid urbanisation. these transdisciplinary case studies should combine biological, epidemiological, medical and veterinary research together with methods of behavioural and social science research. in addition to knowledge and know-how acquired from biological, ecological, health, medical and veterinary sciences, this pandemic confirms the crucial function and contribution of access to many types of resources when they are needed; in particular, sufficient stocks of medical equipment; hospital wards with specialised infrastructure; replenished supplies of pharmaceutical products; adequate numbers of trained and qualified medical doctors, nursing staff and auxiliary personnel in hospitals, medical centres and nursing homes for elderly persons and coordinated uses of all these resources when the virus is first diagnosed in specific localities. we now know from experience in asian countries and italy that the timing of responses to the first diagnosis of this virus in specific cities, and mega-urban regions, is crucial for the effectiveness of counter-measures. the comparison and stark contrast between interventions and resources in asian cities, including seoul, taipei and singapore, compared with london and new york, is a timely reminder that anticipation by proactive thinking, and preemptive measures by prospective planning, vary considerably between countries and cities irrespective of their gdp or political regime. the asian cities learned important lessons from the coronavirus sars-cov- in - , which impacted more than countries, highlighting the fundamental contribution of preemptive measures founded on empirical knowledge. also, national and city comparisons confirm the vital contribution of strategic public health policies after a global shift towards the privatisation of medical and health care services in the last three decades in many countries. ironically, many advocates of laissez-faire and neo-liberal economics now expect governments to intervene to support private enterprises that are financially fragile or bankrupt, fig. effective responses to the complexity, emergence and uncertainty of coronavirus sars-cov- and the compound nature of health, economic and social impacts of covid- require understanding and implementing the virtuous relations between disciplinary knowledge and professional know-how, several types of resources, coordinated multi-level governance, and individual and collective behaviours that should be combined in transdisciplinary contributions. © roderick lawrence including those that failed to provide much needed medical and pharmaceutical equipment currently imported from foreign countries [ ] . the third prerequisite condition that influences effective national, city and communal responses to counteract the transmission of coronavirus concern individual, household and community adherence to behavioural norms and new regulations introduced by national and local governments. some interventions by governments and public administrations concern regulating personal behaviour and interpersonal contacts. for example, norms and rules include different degrees of confinement, controlled access to outdoor public spaces, markets and shops, social distancing, wearing masks and washing hands. public adherence to these norms and rules cannot be assumed owing to cultural, social and psychological reasons including religious customs, spiritual beliefs, group identity and the notion of individual liberty. diverse individual and group perceptions of health risks attributed to coronavirus coexist in societies that have endorsed the supremacy of individualism at the expense of collectivism, the authority of divine providence and rights of humans above all other living organisms on earth. in this context of heterogeneous lifestyles, values and worldviews, appropriate data and information should be effectively communicated to target groups in order to create responsible behaviour not only for individual health, or social well-being, but also for the common good. we now know there are crucial compromises and trade-offs between individual liberty and personal responsibility, as well as fundamental collective choices about how to respond to economic, health and social threats in the context of uncertainty and vulnerability. we also know that a patient-centred strategy that targets highly vulnerable individuals and groups should be complemented by a community-centred approach. the negative impacts of this pandemic confirm a wellknown correlation between socioeconomic inequalities and mortality rates of populations at national, regional and city levels [ ] . while targeting populations should identify and respond to the needs of vulnerable groups, this pandemic confirms that an area-based approach in countries and cities is also pertinent (e.g. wuhan in the province of hubei, china; bergamo and lodi in the province of lombardy, italy). this dual approach, often used in environmental health interventions, underlines the importance of working with an in-depth understanding of the contextual conditions in which the coronavirus has been diagnosed. normative behavioural codes and rules should not ignore the societal context including inter-and intra-urban differences. notably, a who recommendation to wash hands repeatedly is unrealistic for all those people (an estimated million people, % of the world's population) who do not have access to a supply of affordable, clean and safe water [ ] . this brief commentary confirms that our livelihood and our health are strongly influenced by the biological, ecological, financial, political and cultural milieu in which we live. this milieu, our habitat, and our livelihoods, are founded on fundamental monetary and nonmonetary values. the extraordinary situation of the current pandemic should be a catalyst for rethinking the hierarchy of priorities and values used implicitly and explicitly to sustain our societies. the capacity of public authorities, private enterprises, scientists, practitioners and community associations to respond effectively to major public health threats, such as this coronavirus, should be founded on in-depth understanding of the medical, veterinary and societal variables that influence health and quality of life in specific cities. there are significant differences between health impacts in geneva and zurich, switzerland; or between adelaide and sydney in australia; or between boston and new york city in the usa, and these differences need deciphering. in each city, a dual temporal perspective should be used to understand its particularities. initially, short-term responses should respond to patients and curtailing the transmission of the virus within and between cities and countries. this immediate response should be supplemented by mid-and long-term responses founded on strategic actions initiatives that reduce health and economic vulnerability. the growing number of accounts of the impacts of coronavirus in countries and cities north and south of the equator presented by the mass media in recent weeks highlights the shortcomings of neo-liberal economics and the fragility of human life in a world that has been transformed by rapid globalisation and urbanisation. these ongoing processes around the globe have reduced the resilience of many countries and cities to counteract global threats because they have lost their capacity to act autonomously after becoming subservient to global production processes and trade with foreign countries in international markets (e.g. dependent on imported face masks, pharmaceutical products and ventilators from abroad to meet national demand). some wealthy countries, including switzerland, rely heavily on foreign medical and nursing staff to efficiently operate public and private hospitals. surprisingly, some national governments have reacted by reintroducing controls at national borders, which has been ineffective in limiting the propagation of the pandemic to over countries, and the transmission of the virus-provoking excess mortality in countries. global governance is not possible if some countries do not comply with international agreements [ ] . these expressions of nationalism and sovereignty ignore that a global pandemic cannot be contained by closing national borders. the main focus of discussion in european and other countries about the impacts of this pandemic on national economies has concentrated on lower production and consumption (gdp) in , the need for public financial support to maintain private enterprises affected by the pandemic, and grants for employees in the formal sector who have become unemployed. the absence of attention to the impacts of this coronavirus on people working in the informal sector reinforces the lack of concern about health impacts of workers in all sectors (including formal health services, and personal care and welfare) [ ] . it is unrealistic for workers to respect behavioural codes and rules that ignore that person-toperson contact is the basis on which daily work and income depend. media reports indicate that many workers, including doctors and nurses in hospitals and nursing homes, do not have the personal equipment necessary to protect them. finally, public anxiety about this situation, supported by mass media and social networking, should raise major concerns about the quality of life and resilience of all peoples that can be influenced by major ecological threats (e.g. climate change and extreme weather events); economic instability (since in many countries); technological accidents (e.g. fukushima in ) and ongoing civil unrest and warfare in several continents. we need to rethink the real interconnected nature of our lives and the livelihoods of others on earth in contrast to the false claims for nationalism and protectionism in some countries. notably, we recall the plight of many victims of hunger and malnutrition that can be avoided by concerted action. we underline here that about million people die of hunger and malnutrition each year, and million of these are children who starve to death while about a third of all food produced is disposed as waste. likewise, the absurdity of the request for social by staying 'at home' given that not less than million people are declared homeless and . billion are estimated to live in inadequate housing [ ] . the fundamental issue is whether the current pandemic will be a catalyst for collective radical rethinking about the future of 'us and others' in a world that should become more ecologically responsible, more economically just, and more socially equitable for the common good, or a shared quest for returning to 'business as usual'. emerging infections: what have we learnt from sars? lessons from italy's response to coronavius academic institutions and one health: building capacity for transdisciplinary research approaches to address complex health issues at the animal-humanecosystem interface beware the fragility of the global economy global water, sanitation, and health (wash do not violate the international health regulations during the covid- outbreak according to the international labour organization (ilo), about billion people work informally, most of them in emerging and developing countries. see ilo 'women and men in the informal economy: a statistical picture united nations, department of economic and social affairs publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations and invited professor at the international institute for global health at the united nations university (iigh-unu) in - . he has been a member of the scientific advisory board for interdisciplinary and transdisciplinary research at the swiss academy of sciences (scnat) s i n c e key: cord- -h wj m u authors: keil, roger; ali, harris title: governing the sick city: urban governance in the age of emerging infectious disease date: - - journal: antipode doi: . /j. - . . .x sha: doc_id: cord_uid: h wj m u abstract: based on a case study of the severe acute respiratory syndrome (sars) outbreak in toronto, canada, this article suggests that we may have to rethink our common perception of what urban governance entails. rather than operating solely in the conceptual proximity of social cohesion and economic competitiveness, urban governance may soon prove to be more centrally concerned with questions of widespread disease, life and death and the construction of new internal boundaries and regulations just at the time that globalization seems to suggest the breakdown of some traditional scalar incisions such as national boundaries in a post‐westphalian environment. we argue that urban governance must face the new (or reemerging) challenge of dealing with infectious disease in the context of the “new normal” and that global health governance may be better off by taking the possibilities that rest in metropolitan governance more seriously. avian flu has begun to capture the imagination of world publics in recent years as the h n virus spread from its perceived origin in east and southeast asia to turkey and potentially to western europe (davis ) . newspapers and television corporations have discovered the pandemic as a topic of interest. governments, businesses, and civic organizations at all scales have drawn up preparedness plans. this newfound interest in the threat from emerging infectious disease has a recent precedent. in the spring of many parts of the world experienced an outbreak of severe acute respiratory syndrome (sars). in many ways, the sars outbreak is now being read as a stage rehearsal for what many public health experts believe will be a much larger epidemic once the h n virus, which has so far only spread from infected birds to humans, mutates and leads to direct human-to-human infection. sars, a previously unknown disease, is much different from h n but the way it was handled by health authorities around the globe can potentially teach us some lessons about future pandemic preparedness. this article looks at the urban governance aspect of these urban governance in the age of emerging infectious disease lessons. we rely on the rich and productive output in urban governance studies but will argue that this literature has had a particular blind spot: the relationship of urban governance restructuring to emerging infectious disease (eid). urban governance must be prepared to deal with infectious disease. at the same time, global health governance overall may be improved by realizing the possibilities that rest in metropolitan governance. a new "post-westphalian" constellation of post-national state power (fidler ) poses previously unknown demands on the governance of urban regions in the area of infectious disease control. while there has been much attention in recent years on the significance of global city regions in the new world economy (brenner and keil ) and while the governance and regulation of these regions has captured the imagination of academics and policymakers alike (buck et al ; harding ; heinelt and kübler ; kantor and savitch ; scott ) , little has been said specifically about the growing pressures posed by the potential threat of infectious disease through the global network on urban governance. rather than operating solely in between the often contradictory challenges of social cohesion and economic competitiveness, urban governance may soon have to be more centrally concerned with questions of widespread disease, life and death (agamben ) and the construction of new internal boundaries and regulations just at the time that globalization seems to suggest the breakdown of some traditional scalar incisions such as national boundaries. in making connections between the traditional discussion of public service provision between competitiveness and cohesion and the more dramatic and urgent questions about disease and health, life and death, we also consult work that has-in a foucauldian mannermore directly engaged with issues of (bio)power and governmentality (osborne and rose ; rose ) . for the area of urban planning and governance a more or less critical literature has begun to explore the spaces that cities have to maneuver in the rather open field of infectious disease preparedness planning and public health since the onset of the "new normal" after the attacks of / malizia ; matthew and macdonald ) . some work has explored the historical precedents of variations in how cities have fought infectious disease in order "to help us plan for the battles against disease that will be part of our future" (leavitt : ) . howard markel has put forward the observation that "[n]othing less than a cooperative partnership of nations, healthcare professionals, researchers, public health specialists, concerned corporations, philanthropies, and individuals will suffice to safeguard the world against the many public health problems we face today" ( : - ) . still, we believe more specific work needs to be done clarifying and determining the role municipal institutions of health governance can play in the global system of health governance. it is possible to view the sars outbreak of as a direct consequence of increased connectivity due to globalization in general and advances in transportation technologies in particular (brockmann, hufnagel and geisel ; guimera et al ) . in order to understand the effects of connectivity in the global city system on the health of people in these cities, it is necessary to develop new and innovative ways of thinking about what is connected in what ways in that system . there is a strong and growing consensus in the literature on globalization and health/disease that realities in a post-westphalian world need a rethinking of governance structures on a variety of scales between the global and the local (ali and keil forthcoming; fidler ; gandy b; harris and seid a; knobler et al ; lee ; markel ; mclean et al ; whiteford and manderson ) . in this article, we ask what the consequences of the connectivity for health governance will be. although public health policy delivery has always been an intensely local process, the "westphalian" state system had defined health policies in national containers ordered and segmented among others by world health organization guidelines but mostly under the sovereign jurisdiction of nation-states. public health was national health and health policy was national health policy under this regime. who interventions had to occur in the framework of national sovereignties, whose concern was with both popular health and economic welfare-not necessarily in this order (fidler ; heymann ; heymann interview, geneva september ) . when sars hit major metropolitan regions in asia and north america the need to rethink both global and sub-national health governance was exposed. the reliance on the hierarchical and hermetic system of nationally based health policy was put to the test as the who attempted to carve out a novel activist role in protecting global health beyond national interests and as sub-national governments, economic and civil society players moved to react to a localized global health crisis with coordinated action of their own (abraham ; fidler ) . at both ends of the redefinition of international health governance-the local and the global-an "institutional void" (hajer ) existed which could not be filled automatically by traditional, national health governance institutions and their international affiliates. we posit that urban governance will increasingly have to deal with questions of vulnerability and risk related to eids. vulnerability to eids is perhaps more pronounced in urban areas, where the majority of us live. urbanization increases the statistical odds that microbes are being spread (pennington ) . the aggregation of human populations into highdensity urban "islands" has important effects in providing the host reservoirs for maintaining infection chains (haggett ) . accelerated land use changes in and around urban areas have heightened the vulnerability of urban populations to infectious disease (patz et al ) . vulnerability is a notion which in close proximity to other "essentializing" western discourses such as tropicality and development (bankoff ) . it refers to a state outside of the west. yet, the notion of vulnerability has taken on renewed significance after september , particularly in the usa, as the "sense of security of many american citizens" was punctured (simon : ) . it has particular relevance to the case of sars which shattered the local public health and hospital systems of toronto, hong kong and singapore and the public perception of their safety. these cities' "globality" means that an infectious disease cannot be contained by a purely exclusive "local" strategy of public health. most vulnerability reduction policies tend to be largely limited to making safety modifications to key buildings and critical infrastructures, but the sars case illustrates that the human/cultural dimension must also be considered in the effective management of disease outbreaks in the contemporary global city. thus, isolation and quarantine did appear effective in fighting the outbreak, but what more could be done to prepare such containment strategies in case of future outbreaks in the global city? it is clear that we need to better understand the interactions of local modes of healthcare regulation in a globalized urban environment and the specific dimensions of urban vulnerability to public health threats in the global city setting (d'cunha (d'cunha , . global cities are usually considered a specific category of urban centres. they often have more to do with each other than with their immediate hinterlands and regions, and they tend to be more like other global cities than like other cities in their national networks (for an overview of the literature, see brenner and keil ) . as the case of sars demonstrated, global cities are not just switching stations for flows of capital and labour allegedly ordered in a tight network of privilege and command functions. they also are transfer stations of various and contradictory dynamics of the globalized economy. among them are city-country relations, connections between the developed and the developing world, even human-animal interrelations (brenner and keil ; sassen ; taylor ) . the sars virus is said to have travelled to toronto from hong kong through a chain of connectivities-or to use another term, an actor network-that includes the civet cat, live ("wet") animal markets, cross-border commuters across the spectrum of the labour market, hotels, transnational travellers, airports, healthcare workers, hospitals, etc. contributing factors were faulty or badly maintained aeration and plumbing systems in high-rise buildings, air travel in hermetically closed airplanes, hospital systems, diasporic relations among relatives, and so forth. at each link of this rather disparate chain, sub-connectivities are present, which we have called the capillaries of the global system: family relationships, small and parochial religious communities, more or less isolated (and even criminalized) food-handling practices, hospital hygiene codes, etc, all sub-realities of a larger global network of relationships. these subrealities are often not accounted for in descriptions of global cityness although they seem to be central to our understanding of certain consequences of globalization, such as the spread of eids. they are not just the micro versions of larger macro processes constituted elsewhere: they are co-constitutive of the global realities themselves. insofar as they belong to the larger processes of metabolism, these sub-realities are part of the ecological substrate of the global city system. we argue that it is exactly the dialectics of fixed infrastructures, built environments, institutional arrangements, reliable legal constructs, functioning hospitals (and their governance arrangements) of global cities on one hand and the unfixed, mobile, constantly re-articulated flows of people, non-human organisms, information and things that move through them, on the other. recognizing this dialectic also implies the critique of functionalistic and technological images of global connectivity in fixed network nodes. we rather postulate the topological, agency-founded co-constitution of such nodes gandy a; smith ) . urban governance has become a standard phrase in urban political studies. following jon pierre, urban governance can be defined as "the pursuit of collective goals through an inclusive strategy of resource mobilization" ( : ). as the focus of urban scholars has moved from "the comparative study of constitutions and city charters" to decision-making processes that involve state, market and civil society actors in all areas (gissendanner : ) , a broad spectrum of urban governance research has now been produced with case studies, comparisons and further theoretical developments (see, for example, brenner ; elwood ; harding , forthcoming; heinelt and kübler ; kantor and savitch ; kaufmann, léautier and mastruzzi ; pierre ; sellers ) . north-america-centred work on urban regimes, which continues to produce excellent case and comparative studies (for a recent summary of this literature see stone ) is complemented by a strong european-centred body of work of mostly comparative nature (brenner ; buck et al ; legales ) . in some of the literature, the shift to governance has been discussed in relation to the globalization and neoliberalization of cities, processes which in many cases have been seen as causative of this shift (brenner and theodore ) , while other authors have emphasized the role governance has itself played in facilitating these processes in turn. the comparative literature on urban governance restructuring has various intersections with the rescaling of the "political pathology" of infectious disease containment (fidler ) as the global and neoliberal contexts of current restructuring at the urban scale have been the focus of much theoretical and conceptual work. of these intersections, the new focus of metropolitanization deserves our specific attention. brenner's central concern, for example, is with the ways in which "urban governance has served as a major catalyst, medium, and arena of state rescaling processes" ( : ). new collective action at the city-regional level in the many traditional (e.g. economic development and social welfare) and emerging (e.g. environmental, (multi-)cultural) policy fields can be discerned in metropolitan areas around the world. public policymaking increasingly occurs at the metropolitan level as municipal and regional elites deliberately nurture this scale as the basis for international competition (boudreau et al forthcoming; brenner ). yet, there is also an emerging political space at the metropolitan scale, where collective action and claims for local democracy unfold. metropolitanization can mean an internal reconstitution of the political sphere and its articulation with civil society: "there is a diversification of local responsibilities and activities, from the production of local services to, among other things, a proactive role in economic development" (boudreau et al forthcoming) . among these responsibilities and activities may also be health governance at the urban scale. there is ample scholarship on the historical relationship between municipal government and disease both historically and on recent developments, such as the reemergence of tb, the role of urban poverty and diversity vis-à-vis disease or the ravages of aids (see, for example, craddock ; gandy and zumla ; raphael ; shah ). yet despite an increased interest in the relationship of globalization and disease (mcmurray and smith ), there has not been much attention on the specific urban governance aspects of eids in a world characterized by globalizing and global cities. we will argue accordingly that in the face of new threats to the health of urban dwellers caused both by increased technological, economic, cultural and ecological connectivity (globalization) and healthcare restructuring (neoliberalization), we need a renewed focus on the city as a place of potential or real disease and inversely as a place of health. an exception to the dearth of work conceptualizing health and disease as part of the overall governance of world cities has been the research of victor rodwin and michael gusmano ( ) on public health infrastructure in new york, london, paris and tokyo. while not explicitly locating their work in the governance literature, rodwin and gusmano ( : ) have noted: "urban health evokes contrasting images: the city as a center of disease, poor health, and enduring poverty versus the city as a cradle of historical public health interventions, innovative medical cures, and healthy lifestyles for the well-to-do". studying "urban health, particularly the evolution and current organization of public health infrastructure and the health status and quality of life in these cities" and the "important links between local, subnational, and central or federal authorities" (ibid: ) sounds familiar to students of urban governance. rodwin and gusmano have shown the impact of global cityness on localized health governance mechanisms and systems. in their work on new york, london, paris, and tokyo, rodwin and gusmano ( : ) have examined the impacts of "world cities-their health system and neighborhood characteristics-on two outcomes: the use of health services and health status". they found, not surprisingly perhaps, great diversity in which health is factored into the overall global city formation in these four leading global urban centres. their ongoing studies on various aspects of the public health system in these cities reveal the connections between common structural inequalities and social problems in global cities with their health systems. this work fills a void in the research on global cities generally and specifically adds to our understanding of the impact of globally induced social inequality-ie global city formation-on health. it also has the added benefit of being able to help us differentiate between the various health governance systems in cities as diverse as london, paris, new york and tokyo both in their centres and peripheries. rodwin and gusmano have identified four distinct "onerous health risks", which global cities such as toronto, hong kong and singapore confront: the re-emergence of infectious diseases; rising inequalities among social groups; barriers in access to quality healthcare by ethnic minorities and/or the poor; and terrorism and bioterrorism ( : ). all four themes stretch the notion of the city as a defined territorialized place. they point to cities as sites of topological relations that articulate activities and dynamics at various scales (amin and thrift ) . they define, to a large degree, the agenda of global city health governance. yet, as much as rodwin and gusmano's own research sheds light on the place-related aspects of health, it does not itself deal with the network-related aspects of health which is the aspect emphasized in the current article. we suggest adding two important dimensions of the analysis which we believe increase our understanding of the role of urban health governance in the fight against eids. first, the governance of cities today is unimaginable without the modern constitution of the "bacteriological city" at its base (gandy a, forthcoming) , which created managerial processes of a technological, engineering and scientific nature to guarantee public health and to lay the foundation of an economic development and demographic growth ostensibly unencumbered by the incalculable onset of disease outbreaks, which had wrecked urban populations and their economies until the twentieth century in europe and north america. it is on the basis of this century-old history that we now need to rethink urban health governance. a historical process of purification separated the modern city from its natural environments through a set of infrastructures and mechanized metabolic processes such as water and sewer infrastructure, garbage collection and processing, etc (kaika ). the "bacteriological city" as matthew gandy ( gandy ( , a has called the city of the twentieth century, was based on an entirely human-centred purified science, which "othered" animals, externalized disease and-in extreme caseseliminated "less-than-human" humans through technical ingenuity and government biopolitics (foucault ) . the bacteriological city kept the germs in check and allowed for new types of socially cohesive urban relations to take shape: "the emerging 'bacteriological city' involved a medley of different social, political, economic and environmental goals set within the context of a movement away from fragmentary and laissez-faire approaches to urban governance" (gandy : ) . this rationalization of urban governance via technologically reliable networks was based on a universalist interest in public health advances. the currently popular "neoorganicist" view of the city, of which the materialist notion of the cyborg city is a critical extension, puts a new spin on the tradition of the bacteriological city. it has been strongly associated with a transhumanist view of our urban reality, in which, as bruce braun observes, "'barely human' others (iraquis, rwandans, muslims), and 'almost human' companions (monkeys, dogs and cats), are discussed alongside accounts of 'inter-species' exchange (bird flu, sars) in which the boundaries of the human are suddenly porous and mobile" ( : ). such mixing clearly has consequences for governance as the carefully guarded distinctions between people and germs, materialized in the modern bacteriological city, are now being challenged unexpectedly. as a consequence, we now need to figure out collectively where to draw the kinds of regulative boundaries, which we humans may need to survive the imagined or real onslaught of the germs. and such defensiveness is most likely tied up with the regulation of bodies-human and nonhuman-that carry or are suspected to carry the disease. technically, while not necessarily ethically, the sacrifice of millions of ducks or cattle as a reactive of preventative public health measure, is the same kind of measure as airport screening for foot and mouth disease and sars and quarantine of suspected bodies in cities. braun challenges us to think that it is: possible to understand cities, for example as "posthuman" assemblages in ways that both vastly expand our understanding of the actors shaping the urban experience, and that confound our usual understandings of the space and time of urban life . . . writing the sars virus into a "posthuman" toronto explodes the time-space of the city, folding people and animals in china and thailand into bodies on queen street, and revealing time to be multiple and rhythmic-the time of circulation of people and capital but also molecules ( : ). lastly, disease and health have important impacts on the rearrangement of the governance of public/private space. hospitals, quarantine, cultural spaces are fundamentally reassessed and their place in the order of public and private everyday lives and official geographies is recalibrated: what is acceptable in terms of use of space by various bodies in cities? our argument is that while purification and biopolitics were the characteristics associated with the hygienic city of the last century, we have now entered a phase in which the potential reemergence of infectious disease at a mass scale forces us to rethink the relationship of our built environments, our institutional arrangements and our practices as urban dwellers. this has to do as much with the changing nature of cities as basing points of the global economy-to use quite a conventional concept from global cities theory-as with the kinds of reemerging diseases we now have to deal with. second, it is necessary to extend our view beyond the national institutional level when looking at the governance of eids in cities, as extra-national organizations such as the atlanta centers for disease control (cdc) and supra-national organizations such as the world health organization (who) exert significant influence on urban health governance in any country, sometimes not even mediated through national policy or institutions (fidler ; heymann ) . in a global perspective maarten hajer has noted a particular "institutional void": [m]ore than before, solutions for pressing problems cannot be found within the boundaries of sovereign polities. as established institutional arrangements often lack the power to deliver the required or requested policy results on their own, they take part in transnational, polycentric networks of governance in which power is dispersed. the weakening of the state here goes hand in hand with the international growth of civil society, the emergence of new citizen-actors and new forms of mobilization ( : ). municipal public health policy emerges in a context of larger-scale dynamics over which it has little control. global cities and city-states such as toronto, hong kong and even singapore are burdened with responsibilities due to their rising integration into world city networks on one hand and continued lack of self-determined decision-making powers for their complex jurisdictions on the other. in addition, cities like toronto are tied into an increasingly diverse global network of diaspora and migrant cultures at the base of their hybrid globality (goonewardena and kipfer ) . the connection between the globalizing political economy and the cultural and demographic changes it brings with it are crucial to understanding the everyday practices and socio-cultural interactions that characterize today's world and more specifically the everydayness of global cities. toronto-like other cities in the global city network and elsewhere-has taken on far-reaching responsibilities for the settlement of immigrants. this has become a central concern of metropolitan governance now. as in past waves of immigration, cities have become the actual border points for new immigrants. it is important to remember, as nicholas king has reminded us, that under these circumstances, "researchers and public health officials would do well to think in transnational as well as international terms. this means focusing less on the transgression of borders by individuals, and more on the formation of transnational connections between spaces and populations once thought to be disconnected or insulated from one another" ( : ). of course, urban governance is just a fraction of an overall system of health governance, which in the words of fidler ( ) now has to deal with sars as the "first post-westphalian pathogen". fidler also reminds us that as sars represents new problems for public health and creates the need to develop diagnostics, treatments and vaccines in the context of globalization, it breaks down both the sub-national and international framework in which public health has been governed for more than years. in particular, the sars outbreak posed a threat to commonly held views of national sovereignty which allowed nationstates to deal-vertically-with their own health systems internally while negotiating (ideally) at par-horizontally-with other nationstates internationally. the experience with sars points to an interesting dialectics: the existing system is both corroded and withstands the onslaught of the virus. speaking about the us, fidler states, "federalism constructs political borders between federal and state governments. germs no more recognize these borders than they recognize international borders. federalism does not, however, disappear as an influence on public health governance simply because germs do not recognize the boundaries it creates" ( : ). fidler's "political pathology" is pivotal for the understanding of the parameters of health governance today. he carefully charts the landscape of international and now global health governance since the nineteenth century, when the first international sanitary regulations were drawn up among the great powers of the world. these efforts eventually led to the creation of a world health agency, the who, which has operated on a set of tenuous global regulations such as the international health regulations, which have recently undergone redrafting to reflect the specific challenges posed by the fight against sars (fidler ) . the weakness of fidler's otherwise sharp analysis is that it focuses only on one direction of the rescaling of international health governance towards the global level. in answering the question "how to manage borderless bugs in a borderless world", fidler concentrates on the role of new global institutions as well as new non-state actors in the health field. both, he correctly states, narrow the traditional sovereign spaces of health policymaking, even of large states such as china which-begrudgingly-ceded some of its authority to the who during the sars crisis after initially lying to the world about the severity of the disease in its provinces and in the nation's capital. the who emerged as a stronger and more recognized player from the sars crisis and established, for the first time and if only briefly, a global community of eid management (fidler : ; heymann ; preiser ). fidler does not engage with other forms of the rescaling of the westphalian state system such as the one brenner has defined as "metropolitanization" (brenner ) . we have been arguing throughout this article that this metropolitan scale of governance deserves more attention in the regulation of an urban-based global reality. in fact, as the former director general of the who underlined, "who officials every day deal with local communities and officials, around the world" (brundtland, email interview november ). although, in the past, cities have often been directly blamed or linked to disease (gandy : ) , this pattern was supposed to have been superseded by the modernity of the cities themselves. until not too long ago, cities in the west were considered free of catastrophic disease of the traditional epidemic kind. thomas osborne and nikolas rose noted only as recently as that we could observe a shift from a focus on disease to a focus on health in the governance of cities: the city has long been imagined in terms of sickness and health. but in recent decades a new image of the healthy city has emerged: the city as a network of living practices of well-being . . . the very idea of disease in the city has been transformed. it is no longer imagined in epidemic form-the invasion of the urban milieu by cholera or typhus putting its inhabitants at risk of infection. rather, disease and ill health more generally, is imagined in terms of activities (diet and coronary heart disease . . .) and relationships (unsafe sex and hiv . . .). we no longer have the sick on the one side of a division, the healthy on the other-we are all, actually or potentially, sick, and health is not a state to be striven for only when one falls ill, it is something to be maintained by what we do at every moment of our everyday lives ( : - ). recent developments in the wake of sars but also scenarios following a potential outbreak of an epidemic of either a new flu strain or a human form of the avian flu have belied the disappearance of epidemic disease from the urban experience as expressed in this quote. not only is it not true for most cities in the world where people keep being threatened by infectious disease pandemics of all kinds, it is also not true for western cities anymore as sars has shown in utmost clarity. we do agree with osborne and rose, though, when they point out that the governmentality that regulates disease has shifted from the collective to the individual. this is a major biopolitical shift which is mostly played out on the level of urban governance. this interpretation coincides with other work on the changing nature of public health (petersen and lupton ) , which argues that health and disease have been recast as individual responsibilities rather than social ones in the contemporary period [see also sanford and ali ( ) for an elaboration of this argument with respect to sars]. it is exactly this-neoliberalgovernmentality of individualized notions of health and sickness which existed when sars arrived. it is in this framework that we have to understand the new thinking and agency around infectious disease in the city. it adds to the general shift in the current city from traditional notions of control in favour of a more clearly orchestrated mix of state and market interventions. public health governance in the age of sars has-at least potentially-moved to a bundle of strategies that fit well into the overall securitization of urban society which includes "enhanced forms of social control through a mix of architectural, ideological and intelligence-gathering processes" (gandy a: ) . in addition to these developments towards a new governmentality of public health, the sars crisis occurred in a very specific environment, which had been created by the events that followed the attacks on washington and new york city on september , . shortly after september , , american vice president dick cheney was reflecting on what he called a "new normalcy", a notion that was used widely at the time to legitimize changes to long-held understandings of the social and legal makeup of american society (lawyers committee for human rights ). legal scholars and practitioners as well as political pundits and activists of all stripes pondered the meaning of the "new normal" and pointed to the deterioration of basic human and civil rights in the aftermath of the september and subsequent war-related events. "living" in the "new normal" became an object of serious study (simon ) . a legal study examined such changes in the areas of "government openness; personal privacy; immigration; security-related detention; and the effect of us actions on human rights standards around the world" (ibid). while admitting to the necessity of some government action in the wake of / , the report notes "dramatic changes in the relationship between the us government and the people it serves" and voices many grave concerns about the deterioration of civic and individual liberties. beyond its immediate denotation with respect to the changing times after / , the term has since thrived as a powerful (if somewhat clichéd) metaphor that has been bandied about in all kinds of contexts. and despite the clearly problematic context in which "the new normal" was introduced into the political and vernacular vocabulary-or perhaps precisely because of the implications of this context-the term found a wide use in toronto's sars outbreak of . during the crisis politics of the day, particularly in the healthcare system itself and among the politicians involved, "the new normal" quickly became the buzzword for an overall state of emergency that gave policy actors and decisionmakers license to make unprecedented changes and to call for reform of major threads of the social fabric, particularly in the area of public health. the "new normal" became the umbrella term for a situation in which thousands were put into quarantine (or if they resisted into isolation), and nurses-many of whom were infected themselves-were missing from understaffed hospitals, at a time when the overall system of healthcare delivery was admittedly about to "snap" (boyle ) . one of the main users of the concept was the ultra-conservative minister of health for ontario, tony clement, who, for a moment, surfed on the popular wave of the giuliani-brand "roll-up-your-sleeve" and "openshirt-collar" politics of emergency, which swept him into the public spotlight in the spring of . clement became the public face of a social crisis which had repercussions for much more than health policy per se, and touched on issues involving labour relations, "race" relations, multiculturalism and much more. the "new normal" soon became the yardstick for all these types of issues. for instance, in a dispute with nurses about the lack of full-time positions and the potential change to the funding formula, clement said on may : "in the 'new normal' those kinds of things would have to be reviewed through the prism of infection control". around the same time, clement's ministry issued a "backgrounder" in which the "new normal" was "characterized by high standards of practice that reflect a heightened awareness of emerging infectious diseases including sars" and where there is mention of a "'new normal' environment", in which healthcare workers are meant to operate. one set of directions for the faculty of medicine at the university of toronto dated june , stated self-reflexively: the term "new normal" has already become a bit hackneyed in the face of a second wave of sars in toronto. nonetheless, it is a useful term to encapsulate the change in thinking that may be necessary if we are to achieve longer-term containment of sars and any similar illnesses that may come at us in the future (http://www. library.utoronto.ca/medicine/sars/sarsupdate.pdf; emphasis in the original). at other scales, a toronto family doctor, for example, used the term in a "sars diary" she published in a professional journal and concludes, after relating her ordeals of operating under conditions of quarantine: "i guess this is the new normal i've been hearing about" (greiver ). yet another voice was the director of the reputed american centers for disease control in atlanta, julie geberding, who referred to diseases like sars and monkeypox as the "new normal" while addressing a meeting of the american medical association in chicago in . the connection of the "new normal" to state protocol in its dealing with citizens in an anti-terrorist effort is neither surprising nor unintended by those who make the link. the very notion of the "new normal" signifies the intrusion of unusual measures in our everyday lives, in which leaders have to be cut slack in making decisions about political rule, when regular law and understandings of rights become irregular or non-normal. the invocation of legitimized state violence-be it in anti-terrorist war or in imposing quarantine on groups within an urban community-through the concept "new normal" is itself becoming an accepted part of what we consider tolerable. the "new normal" changed both the horizon of expectation, which citizens, users of the healthcare system, travellers, etc may have had and the potential range of action for governments in dealing with the crisis. it has led, at a remarkable rate, to a lowering of democratic potential in the making and practice of policy, in this case health. the rights of both patients and healthcare workers were considerably cut back during the toronto sars crisis. this is true precisely because the crisis transformed a group of previously relatively obscure public health officials and politicians into a group of well-known leadership personalities-donald low, marcia taylor, doris greenspun, colin d'cunha, sheila basrur, tony clement, james young-who took care of democracy while it was dormant in the shadow of the "new normal". this "decisionism with a populist face" was an interesting development not in tune with the zeitgeist of moving from government to governance. it was, however, very much in line with the notion of "performativity", as sars and the crisis it brought to urban society, was "performed" by more or less media savvy actors, who were always only minutes ahead of the general public and the press as the epidemic progressed and ultimately subsided. at the other end of the spectrum of agents "performing" the sars crisis was the ill-fated and pompous appearance of toronto mayor mel lastman on cnn at the occasion of the who's travel advisory against toronto. lastman, ignorant of the context of global health governance in which "his" city found itself and apparently unfamiliar with the who, spouted out venom against the un organization which, in his eyes, unduly interfered with toronto's self-governance. these actors/agents were put on stage by the arrival of the virus and they played "crisis" and invented a new mode of governance as they went along. while they were by no means unprepared for the epidemic, public officials joined regular citizens in performing a disease that no one yet knew. through the ways citizens and experts in toronto (and singapore and hong kong and elsewhere) performed the disease, the world learned about sars. it seems that the "institutional void" hajer ( ) sees emerging in this context was filled, at least on an ad-hoc basis, by rapid policy change in an emergency situation created by the potentially catastrophic threat posed by sars. the ideological precepts of the "new normal" enabled the state to reassert itself as an active participant in public life after neoliberal reforms in ontario had stripped its involvement in many areas of public welfare to the bare minimum and to reinsert itself with some legitimacy in a policy community which had learned to not trust a government that had de-funded public institutions such as healthcare and education at an unprecedented scale (keil ) . this kept the ontario government "in the game" at a critical time-at least until such measures were challenged by the general public, healthcare workers' associations, patients and their relatives and the press. the loss of clear boundaries for jurisdictions is, of course, a direct outgrowth of global city formation and the growing incapacity of the (local) state in particular to deal with crises visited upon an urban region by its growing internationalization (friedmann [ (friedmann [ ] . the growing challenge presented by global city formation to the fiscal and institutional capacity of the local state is exacerbated by the processes invoked by hajer but also by the ongoing re-scaling of political spaces in a rapidly changing world. specifically with respect to global cities, it has been noted that conceptually and pragmatically the business of municipal politics as well as the conduct of everyday life has been both de-localized in profound ways through economic and cultural globalizations, and re-localized through the idiosyncracies of topologies, which bring together the myriad social connectivities in the microcosms of the world's urban centres (smith ) . urban health governance is embedded in a larger system of urban governance with its vertical and horizontal ties to other levels of government and into civil society and the private sector. urban governance in toronto had been characterized by the city's forced amalgamation in , which initially changed the landscape of public policy significantly towards a more competitive, coercive and stratified environment. this coincided with fundamental changes to municipal politics and internal governance processes as the city has been trying to establish a sense of harmonized "good government" and civic engagement after amalgamation. the outcome of these processes was contradictory: on the one hand hardcore neoliberal reforms were rolled out and downloaded by the tory provincial government between and and often followed through by a conservative and boosterist mayor mel lastman who was unapologetically the spokesperson of an aggressive business lobby and particularly the development industry; on the other hand, progressive politicians at the municipal level with the support of a continuously active social and environmental movement sector, the public sector unions and an electorate which had not forgiven the tories for their attack on toronto political traditions. the result of these contradictions was that urban governance in toronto at the time of the sars outbreak was split as continued reform in the municipal administration, and certain "forgotten" policy areas such as food, homelessness the environment-and public healthcompeted with neoliberal development mantra of a business elite which began to use the newly amalgamated city as their strategic terrain for interurban competition. inside the municipal administration, departmental restructuring and harmonization had led to insecurity, at least temporarily, as to the procedures and substance of urban policy when political cultures of suburban jurisdictions were melded with the downtown's more progressive, democratic traditions, which had led to more sustained rights claims of more diverse populations. this progressive city/conservative suburb split in the geography of toronto's urban governance was challenged by the new immigration and settlement patterns, which made suburbs more diverse than the inner city and the inner city potentially less dynamic politically than the multiculturally invigorated suburbs. during the time of the sars outbreak, this shift complicated matters significantly as the crisis was played out in geographic and social areas of the city-scarborough and north york-which remained largely terrae incognitae to the old toronto elite. the sars crisis intersected with business as usual in urban governance in as far as it was recast quickly from a health crisis to an economic crisis once the worst of the outbreak was over. the worry among toronto politicians and business people over lost business in tourism and entertainment fell in line with the usual propensity of urban officials and civic leaders to heave their city above its competitors in economic development, cultural creation and tourist attraction. in this sense, the sars crisis interfered with the strategic goals of the governing regime of toronto and the governing institutions that had created their success. the peculiar balance of social, economic, environmental and state interests in elite and popular circles that made up the governing coalition of the urban region was threatened by sars, which was contextualized in a series of setbacks for the region's economic progress and civic self-esteem, the loss of the bid for the olympic games to beijing in particular. the question was how these changes contextualized health governance in a time of crisis. the institute on governance defines health governance in canada as follows: in canada, the governance of healthcare is built on intergovernmental cooperation, reflecting a formal division of powers regarding healthcare as outlined in the canadian constitution and the charter of rights and freedoms. in addition, governance of healthcare also takes place outside the governmental sphere. this complexity requires organizations, sectors, regions, first nations communities and governments to forge capacities to govern (http://www.iog.ca/ knowledge areas.asp?pageid= , accessed november ). the institute proceeds to define the most pressing healthcare challenges in canada as follows: • critically assessing the alignment of health governance structures and processes with best practices. • reframing the understanding of governance as expanded beyond an individual institution to include mutual accountabilities among providers. • building ways for health providers to share information and work in a complementary way. • strengthening boards of directors, particularly in hospital governance. • building stronger relationships between voluntary sector organizations and government and between the various levels of government, including first nations (ibid). while clearly open to the complexity and multi-scalarity of health governance, this list of priorities is also characterized by a glaring absence of any reference to the role of cities in health governance. this absence is two-fold. there is, on one hand, the traditional obscurity that municipal politics suffers in the canadian state architecture (keil and young forthcoming); on the other hand, there is a more general eclipse at work here which disregards or even dismisses the role of urban governance in the management of societal matters in a post-westphalian world. we believe, though, that urban public health authorities and their associates in local hospitals, urban non-state actors in the health field as well as workers in urban medical settings have played an important role in the detection, identification, monitoring and fight against eids in particular (interviews july to december : toronto public health official, associate medical officer of health-toronto, university hospital network official, microbiologist-in-chief-toronto hospital, ontario nursing association official, public safety and emergency preparedness canada official). they have provided the core responsibilities of public health-assessment, policy development, assurance-often without support and sometimes in conflict with and in contradistinction to higher level health authorities (rodwin and gusmano : fn). one analysis revealed about the ontario situation during sars: the province of ontario was ill-prepared to deal with an infectious disease threat on such a scale. in canada, the provision of healthcare, including public health, is a provincial responsibility. however, the financial and operational responsibility for public health had increasingly been shifted to municipalities such that, at the time of the sars outbreak, funding was shared equally between the two levels of government. this funding shift created a decentralised public-health system, with the province's public-health units operating quite independently of each other (lim et al : , emphasis added) . sanford and ali ( ) have documented aspects of "new public health hegemony" in the response to sars in toronto. they specifically argue that there has been a mix of old and new measures at various scales that was pervasive and that overall a new hegemony around new epidemiological techniques, risk management, morality and security took shape. extending this work to the specific context of urban governance, a number of preliminary observations can now be made in order to characterize the urban health governance challenges identified in toronto during and after the sars outbreaks of . the urban health governance system experienced a very specific set of pressures, which spoke to the kinds of fundamental decisions that have to be made by urban-scaled and municipal authorities in a moment of epidemic disease. affonso, andrews and jeffs ( : - ) have perceptively identified three sets of paradoxes that led to three sets of dilemmas in the governance of the sars outbreak. these paradoxes/dilemmas were, first, that healthcare workers became sources of transmission and active sustainers of the sars case matrix (leading to the dilemma to be forced to decide whose safety gets priority: patients or caregivers?). second, hospitals were sources of sars infection in the community, breaking down the boundaries of medical care and community in threatening ways (leading to the question of how far do providers of healthcare have to go to provide safe spaces?). third, a culturally and ethnically diverse city may be particularly vulnerable to infectious diseases (prompting the question about the relationship of civil liberties and disease control). in terms of urban governance, these three couples of paradoxes and dilemmas denote spatio-institutional uncertainties of a new kind, which challenge traditional modes of integration and regulation of economic institutions (labour markets/work places), specialized functional spaces (hospitals), public institutions (public health agencies), codified private behaviours (patient versus citizen rights), etc. in an urban governance model, questions need to be directed at the particular ways through which state action (public health, security, etc), private sector involvement (providers of masks, medical equipment, drugs, etc.) and civic organizations (ethnic initiatives against racism, protection of workers' rights, etc) and individual civil rights claims (patients, quarantined individuals, travellers, etc) are coordinated by whom, at what scale and with what procedural democratic means. affonso, andrews and jeffs ( ) make a number of incisive and plausible recommendations as to how to improve health governance in future outbreaks of the kind endured in which centre around patient safety and workforce safety, spatial profiling and risk assessment, as well as community mobilization ( : - ) . it is important to note in the context of the question of urban governance before us that each of these intended measures would have a tangible impact on the day-to-day business of governing cities through democratic political rather than managerial-administrative processes at the municipal level. the core dilemmas these processes would face in the reality of current canadian municipalism is first the lack of autonomy local agencies have in the face of an unreformed federalism, which sees cities (and their institutions) as mere units of the administrative state (of the province and canada) and not as political decision-makers on their own terms; and second the tremendous weakening of lower state and governance structures-often despite rhetorical statements to the contrary on the effect of devolution and subsidiarity-in the face of the globalization and neoliberalization of the canadian state, including the increasing porosity towards supra-national institutions such as the who. we have some evidence on how the local state institutions in toronto themselves saw the crisis and what lessons they suggested to draw from it. the former provincial medical officer of health, colin d'cunha ( ) , detailed the various lessons learned from the outbreak, mostly through the lens of health reporting. the provincial scale is extremely important in the canadian system where municipalities are dependent on upper level policy frameworks and financing without much autonomy for local agencies and institutions. urban governance is severely constricted and clearly defined by this situation. while the municipal state may also be the most politicized of the three levels of government, it remains under the tight supervision of the province in particular and while state expenditures have risen consistently since the s in the federal and provincial governments, municipal funds have not kept pace with the demands placed on them through decades of downloading and devolution (villeneuve and séguin, ) . d'cunha, whose provincial agency was responsible for local health units in ontario, notes in particular that the reportable disease information system in place when sars hit, had been introduced in the s. a new system of reporting, the integrated public health information system (iphis), although available since early in the century, was only to be implemented in the spring of and was further delayed through sars. the provincial level system of surveillance was tied in with the global public health intelligence network (gphin). the provincial health protection and promotion act (hppa) makes mandatory disease reporting and control. it was amended after the sars crisis to empower the province to facilitate isolation of infected individuals (d'cunha ) . d'cunha's office was also left in dire straits in the wake of serious de-funding of public health institutions at the provincial level under a tory government after . the provincial health authority appeared very much like an empty shell which had coordinating functions of local authorities but could not muster the resources to do a good job giving direction and provide credible leadership to municipal and regional agencies (interview, associate medical officer of health-toronto, october ) . in the context of this legal and institutional framework, local-scale health agencies do their work. sheila basrur, the former municipal officer of health, and co-authors have noted that the main roles of toronto public health during the outbreak were case investigation and management, identification and quarantine of contacts, disease surveillance and reporting, health risk assessment and infection control advice to health institutions and other community settings (basrur et al : ) . the sars crisis posed a significant stress on the already severely compromised public health system of toronto as other public health services were cut or reduced to "essential services only" (ibid: - ). the kinds of measures under the responsibility of the municipal public health hegemony reflect the temporally layered and overlapping traditions stemming from the "bacteriological city", updated and redefined through more recent developments. the point to note in this respect is the often confusing unevenness in measures from various periods, phases, and moments of urban governance, which were haphazardly re-grouped into a recombinant mix of place-specific sets of trials and errors. while the coercive and enabling qualities of an existing municipal public health system were tested daily with unexpected twists in the proliferation of the disease, a new administrative reality emerged in the shadow of the successes and failures of an iterative policy process. cases of temporal unevenness were, for example, the deployment of quarantine and isolation orders for the first time in years (with no living administrative memory of and hence no experiential knowledge with such measures in the system) and the much younger (but failing) -year-old provincially authorized surveillance system (which had not kept pace with both technological advances and procedural necessities that had occurred since its inception) (basrur et al ) . the unevenness here related in both cases to the fact that two measures at two ends of a developmental scale in public health measures-the rather traditional and rather blunt tool of the quarantine, and the biopolitical, yet informationalized surveillancewere potentially at odds with the constituencies and clienteles they were meant to protect (and whose general rights sensibilities were a far cry from the mid-twentieth century) and, in the case of the failed surveillance, certainly not up to the challenge that the sars outbreak posed. one influential way to understand the local state is to see it as a sphere of influence of both the state and civil society (kirby ; magnusson ) . civil society is dramatically redefined in the context of the "new normal". in the immediate crisis in the spring of , it became rapidly clear that the "new normal" was not just a rewriting of a few hospital protocols and ministry directives. in true fashion of creating a new "governmentality" through new "technologies of power" in the foucauldian sense (osborne and rose ), the "new normal" became a new standard of societal interaction overall, accepted and even disseminated by the "normalized" everyday actions of urban residents, and the yardstick of urban governance. as we are writing this, toronto is going through emergency preparedness week, which calls on everyone to do their part in putting obstacles in the way of harm. the event organizers are clear that they expect citizens to do their part when taking in exhibits under "the theme 'what are your reasons for being prepared?' the city's exhibits will help toronto residents increase their awareness of emergency-preparedness issues and answer this question for themselves. residents will have the chance to speak with representatives from the city's co-ordinated emergency response teams, view emergency equipment, and pick up important personal emergency preparedness literature" (http://www.toronto.ca/wes/ techservices/oem/index.htm, accessed may ). while civic duty is part of the overall deal, awareness of the possible pitfalls of running a society on an emergency mindset are also part of the public debate. gro harlem brundtland's powerful statement that "with globalization, a single microbial sea washes all of human kind" (quoted in harris and seid b: ) stands as a starting point of our considerations here. like brundtland, who was the director general of the who during the sars crisis, "hundreds of thousands of men and women around the world devote their working lives and intellectual creativity to protecting our health" (markel : ) . that they do this in a wide variety of institutions-state and non-state; private sector and civil society basedand that they are crossing boundaries of disciplines and professional practice all the time, is an important insight: the crisis of the nation-statebased system does not lead to a simple replacement of the international by an elusive global system of health governance. instead, it is the conviction that undergirds this article that certain re-territorializations are key to the reworking of health governance globally. leading science journalist laurie garrett wrote in her prescient betrayal of public trust ( : ) that "[s]afety . . . is as much a local as international issue. in public health terms every city is a 'sister city' with every other metropolis on earth". particularly "metropolitanization" is of great consequence as urban areas have been in the centre of re-emerging diseases such as sars and tb. on the basis of evidence from the sars outbreak in toronto, canada, we have argued in this article that more attention needs to be paid to the changing relationships of urban governance and (re-)emerging infectious disease. towards that end, we specifically looked at two dimensions of urban governance during the sars crisis. first, the way the legacy of the "bacteriological city" was reinterpreted in the sars crisis; second, the way in which the local health governance was embedded in a "post-westphalian" order of health governance. through reading these two dimensions against one another, we have discussed how urban governance-under potentially lasting conditions of the "new normal"-must face the new (or reemerging) challenge of dealing with infectious disease and that global health governance may be better off by taking the possibilities that lie in metropolitan governance more seriously. the toronto case study has revealed a rich casebook of evidence on how state institutions at various scales from the global to the localin constant interaction with civil society and economic actors-have shaped a new modus operandi in how to deal with infectious disease threats in a globalizing environment. not only have cities played a major role as sites and conduits of disease, they have also picked up their share of participating in new forms of governance that brings the (local) state back in. having said that, however, we also showed that both concepts-city and state-are becoming perforated as the "institutional void" around emerging infectious disease corrodes firm boundaries between jurisdictional responsibilities of territorial states and city regions. while sars pricked the skin of the global city system and showed the relative permeability of the westphalian nationstate order by germs, it reconfirmed a certain rigidity of borders (both external and internal) for human mobility. as global health governance made airports biopolitical switching stations and public health officials reverted to quarantine and other measures of sequestration, the state reaffirmed its power in no uncertain terms. as in the early days of the bacteriological city, when municipal administrations created a physical and social infrastructure of hygiene in the struggle against epidemics, urban governance gets assigned new responsibilities ranging from flu preparedness to surveillance once again. but the city is not what it used to be. in an age of heightened urban unboundedness our image of cities is recast "as nodes that gather flow and juxtapose diversity, as places of overlapping-but not necessarily connected-relational networks, as perforated entities with connections that stretch far back in time and space and resulting from all of this, as spatial formations of continuously changing composition, character and reach" (amin : ) . the new politics of place that amin sees on the horizon in this new world of perforated urban spaces now also has to take into account the politics of infectious disease we have discussed in this article. endnotes sars is caused by a coronavirus, which is assumed to have moved through zoonotic infection from civet cats in southern china to rural and urban human populations there, and subsequently to urban populations in several large, globalizing cities around the world, with beijing, guangzhou, hong kong, singapore and toronto among the ones that were affected most. in the canadian metropolis toronto sars claimed lives in two consecutive outbreaks, as people were confirmed infected cases, and thousands were quarantined. the economic fallout of the outbreak was tremendous as entire economic sectors-tourism, film, etc-suffered huge losses from which they have just begun to recover two years later (abraham ; fidler ; mclean et al ) . we have discussed these connections in greater detail in where we have brought foucault's work to bear on an analysis of racialization of the sars outbreak in toronto; see also sarasin (forthcoming) on this subject. this dialectics is different from but related to the one that gandy refers to when he points out the "devastating disparities between the mobility of capital and labour that condemn much of humanity to economic serfdom" which exist in the shadow of the "connections, networks and flows" which some see as characteristic of our current society (gandy a: - ) . defined as "the capacity of local officials to perform the core functions of public health": assessment, policy development, assurance (rodwin and gusmano : fn) "'westphalian' refers to the governance framework that defined international public health activities from the mid-nineteenth century" based on the political logic of sovereign nation-states that had come into existence after the years war (fidler : - ) . we are grateful to one of the reviewers who correctly pointed out that concentrations of disease in pre-industrial port cities had already led to internationally agreed-upon practices of disease control such as quarantine. we have reviewed this history in ali and keil (forthcoming). in canada, the healthcare system has long been seen as a major area of neoliberalization. we have seen the privatization of healthcare delivery that has potentially damaging effects on the model of social solidarity which underlies that country's medicare system. at the demand end of the neoliberalization and privatization of healthcare, individuals are now more likely to be held responsible for their health and to pay for services needed to address health issues. there is a large critical literature on this in the public domain, of which these are good examples: "canada needs a public health care system" (canadian dimension august ) and gindin et al ( ) . http://www.health.gov.on.ca/english/providers/program/pubhealth/sars/docs/new normal/dir bg .pdf, accessed february ). such measures were, for example, publicized widely on the website of the university health network, http://www.uhn.ca/home/sars/. cdc director warns sars, monkeypox are the "new normal", reported on wane-tv, http://www.wane.com/global/story.asp?s= , accessed february . she also was paraphrased as saying that "world travel has become common" that "anti-terrorism efforts have helped public health officials prepare for the infectious disease threat" and called "sars a very sobering reminder of the global community people share". geberding made similar comments on cbs television's early show on june , http://www.cbsnews.com/stories/ / / / earlyshow/health/health news/main .shtml, accessed february . "performativity" is inspired by the definition of "performance/name of action" proposed by bruno latour ( : ) , meaning that an "actor does not yet have an essence. it is defined only as a list of effects-or performances-in a laboratory. only later does one deduce from these performances a competence, that is, a substance that explains why the actor behaves as it does". mayor lastman was interviewed on cnn by aaron brown on april and displayed stunning ignorance of the who, its purpose and powers (the globe and mail :a ). a similar chain of events occurred when the ontario government, after making much noise about privatizing electricity supply and provision, stepped into the blackout crisis of august . after having lost all credibility earlier that year in questions of electricity, the ensuing crisis mode allowed premier ernie eves to appear on newspaper front pages as a strong leader who gets things done and problems under control. this section is based on boudreau et al (forthcoming), keil ( ) , keil and boudreau ( ) , keil and young (forthcoming) , kipfer and keil ( ) . our research in toronto benefited greatly from interviews with the following experts: bannerji a, toronto, march ; booth c, toronto, january ; finkelstein m, toronto, october ; gardam m, toronto, november ; low d, toronto, november ; macdonald v, toronto, september ; young j, toronto, december . d'cunha was removed from the position he held during the crisis because many considered his performance during the crisis as incompetent and insufficient. he was replaced on february by sheila basrur. for a comparative chinese perspective, see hongyi ( ). it must be noted, however, that canadians on the whole are less civil liberties conscious than most americans. collective necessity and public security often trumps concerns over individual freedoms in canada. whether it was the war measures act during the october crisis of the s when tanks rolled in montreal or in current public opinion about stricter security measures in the "war on terrorism", canadian pollsters have consistently found strong support for "stability and security" (clark ) . twenty-first century plague: the story of sars the urban geography of sars: paradoxes and dilemmas in toronto's health care homo sacer: sovereign power and bare life global cities and the spread of infectious disease: the case of severe acute respiratory syndrome (sars) in toronto ) pandemics, place, and planning: learning from sars regions unbound: towards a new politics of place rendering the world unsafe: "vulnerability" as western discourse sars: a local public health perspective new state spaces in canada: metropolitanization in montreal and toronto compared clement feared system may snap. the toronto star june:a braun b ( ) querying posthumanisms new state spaces: urban governance and the rescaling of statehood spaces of neoliberalism: urban restructuring in western europe and north america canadians want strict security, poll finds. the globe and mail city of plagues: disease, poverty and deviance in san francisco the sars experience in ontario, canada. presentation to ontario sars commission partnerships and participation: reconfiguring urban governance in different state contexts sars: political pathology of the first post-westphalian pathogen frankfurt: suhrkamp friedmann j ([ ] ) the world city hypothesis life without germs: contested episodes in the history of tuberculosis cyborg urbanization: complexity and monstrosity in the contemporary city deadly alliances: death, disease and the global politics of public health betrayal of trust: the collapse of global public health methodology problems in urban governance studies spaces of difference: reflections from toronto on multiculturalism, bourgeois urbanism and the possibility of radical urban politics the new normal: a sars diary the worldwide air transportation network: anomalous centrality, community structure, and cities' global roles geographical aspects of the emergence of infectious diseases policy without polity? policy analysis and the institutional void european science foundation: "forward look on urban science metropolitan governance in the st century: governing capacity, democracy and the dynamics of place city of flows: modernity, nature and the city how to study comparative urban development politics: a research note governance and the city: an empirical exploration into global determinants of urban performance common-sense" neoliberalism: progressive conservative urbanism in toronto, canada is there regionalism after municipal amalgamation in toronto london: verso kipfer s and keil r ( ) toronto inc.? planning the competitive city in the new toronto power/rosistance: local politics and the chaotic state learning from sars: preparing for the next disease outbreak lawyers committee for human rights ( ) assessing the new normal: liberty and security for the post-september united states public resistance or cooperation? a tale of smallpox in two cities health impacts of globalization: towards global governance european cities: social conflicts and governance collateral damage: the unforeseen effects of emergency outbreak policies the search for political space planning and public health: research options for an emerging field cities under siege: urban planning and the threat of infectious disease sars according to mel. the globe and mail sars: a case study in emerging infections diseases of globalization: socioeconomic transitions and health governing cities: notes on the spatialisation of virtue unhealthy landscapes: policy recommendations on land use change and infectious disease emergence too much fuss? hugh pennington on the sars virus the new public health: health and self in the age of risk. thousand oaks: sage pierre j ( ) comparative urban governance: uncovering complex causalities presentation at conference "invisible enemies the world cities project: rationale, organization, and design for comparison of megacity health systems powers of freedom: reframing political thought the new public health hegemony: response to severe acute respiratory syndrome (sars) in toronto re-placing the nation: an agenda for comparative urban politics public health and urban development: the plague in surat world city topologies looking back to look forward: reflections on urban regime analysis world city network: a global urban analysis power and decision-making in the city: political perspectives global health policy, local realities: the fallacy of the level playing field this research has been generously supported by a social sciences and humanities research council canada (sshrc) standard grant. we gratefully acknowledge the research assistance of claire major and sarah sanford. key: cord- -dr dxm authors: wu, ziqiang; liao, hao; vidmer, alexandre; zhou, mingyang; chen, wei title: covid- plateau: a phenomenon of epidemic development under adaptive prevention strategies date: - - journal: nan doi: nan sha: doc_id: cord_uid: dr dxm since the beginning of the covid- spreading, the number of studies on the epidemic models increased dramatically. it is important for policy makers to know how the disease will spread, and what are the effects of the policies and environment on the spreading. in this paper, we propose two extensions to the standard infectious disease models: (a) we consider the prevention measures adopted based on the current severity of the infection, those measures are adaptive and change over time. (b) multiple cities and regions are considered, with population movements between those cities/regions, while taking into account that each region may have different prevention measures. while the adaptive measures and mobility of the population were often observed during the pandemic, these effects are rarely explicitly modeled and studied in the classical epidemic models. the model we propose gives rise to a plateau phenomenon: the number of people infected by the disease stay at the same level during an extended period of time. we show what are conditions needs to be met in order for the spreading to exhibit a plateau period, and we show that this phenomenon is interdependent: when considering multiples cities, the conditions are different from a single city. we verify from the real-world data that plateau phenomenon does exists in many regions of the world in the current covid- development. finally, we provide theoretical analysis on the plateau phenomenon for the single-city model, and derive a series of results on the emergence and ending of the plateau, and on the height and length of the plateau. our theoretical results match well with our empirical findings. comprises the people who can be infected by the disease, the infected part is the part of the population who is infected and can transmit the disease, while the recovered part is the one who has been out of the spread process. sir and related models are well studied in the literature. however, during the covid- pandemic, many regions gradually adopt adaptive prevention strategies to try to balance between epidemic prevention and economic growth, and different regions often employ different prevention strategies. this may bring new phenomenon that does not exist in the standard epidemic models. in this paper, we propose two extensions to the standard infectious disease models: (a) we consider adaptive changes in prevention strategies based on the current infection severity; and (b) we consider multiple regions with population mobility while each region may employ different prevention strategies. for simplicity, we refer each region as a city henceforth. we first conduct simulation studies on the proposed model using parameters learned from the real-world data, and observe that in many situations the epidemic development has a period where the number of existing infected people stays at the same level, for which we call it a plateau period. we discover that in the single-city model, the plateau may only occur under certain conditions, and their heights and length may differ. for example, the height of a plateau seems to be positively correlated with the prevention threshold used to trigger the changes in prevention intensity, but not affected by other prevention measures. in the multi-city model, we discover that the plateau always co-occur among all cities, even when some city's prevention strategy would not generate a plateau in the single city model. we next verify from the real-world data that plateau phenomenon does exists in many regions of the world in the current covid- development, indicating that this is an important phenomenon to study. finally, we provide theoretical analysis on the plateau phenomenon on the single-city model, and derive a series of results on the emergence and ending of the plateau, and on the height and length of the plateau in the single-city model. our theoretical results match well with our empirical findings. to summarize, the key contributions of this paper are as follows: • we extend the sir model to incorporate adaptive prevention strategies and population mobility among different regions that also employ different prevention strategies. • we empirically verify through simulations and real-world data that an important plateau phenomenon exists, and summarize some interesting properties on its appearance and characteristics in the single-city model and relationships among plateaus in the multi-city model. • we conduct theoretical analysis on the properties of the plateau and our theoretical results match well with the empirical findings. most of the existing epidemiological studies based on covid- can be divided into the following four categories. research on the epidemiological characteristics of covid- . although most of the attributes of sars-cov- cannot be obtained by epidemic analysis, the epidemiological characteristics of covid- can be estimated. most of the works [ , , , , ] focus on the study of the basic reproduction number r of covid- , which can reflect the propagation ability of sars-cov- . other works [ , , , ] analyzed the characteristics of covid- such as generation interval (cases doubling time). prediction of the virus trend. by combining real data with the model, these works aims to predict the development of covid- . since the beginning of the covid- outbreak, it has been a hot topic. the most common method to predict the number of futures infections relies on real-time data [ , , , , ] . due to the global characteristics of the epidemic, many focused on combining population mobility data with the spreading model [ , , , , ] . improvement of the epidemic model. apart from the population mobility, there are additional aspects that were studied to enhance the quality of the prediction. the seaird model allows for further division of the population [ , , ] . environmental parameters were also added to the models [ , ] , and machine learning algorithms were used [ , ] . exploration of the effects of prevention measures. some countries try their best to prevent covid- , while others wait for mass immunity. the significance of prevention has become the subject of many studies [ , , , ] . based on the development of the epidemic situation before and after prevention, the role of prevention was analyzed. almost all the results affirmed the role of prevention, and pointed out that the epidemic would worsen more seriously without prevention. these works have studied various aspects of on covid- pandemic, but none of them looked into the effect of adaptive changes of prevention measures over time on the epidemic development, and none of them study the plateau phenomenon that appears in practice. this is the subject of our study that differentiates ours from existing studies. traditional epidemic models such as the sir model [ ] do not model behavioral changes in the population that could change the virus propagation dynamics. however, as we have seen with the covid- epidemic, people change their behaviors due to the epidemic either voluntarily or by government restrictions, such as wearing masks, reduce traveling and gathering when the epidemic is getting severe, until the epidemic situation is getting better. moreover, different geographic regions could impose different prevention strategies, and it is further complicated by the cross-regional population movement. in this paper, we incorporate the constantly changing prevention measures as well as the population mobility between regions into the sir model. for the covid- with latent period, we do not choose the seir model, because using the sir model in the process of studying the prevention strategy can simplify the analysis process, and is no different from the seir model. for simplicity, we refer regions as cities, but in reality they could represent either cities or provinces, states, counties, or communities. our single-city model is based on the sir model [ ] , in which each individual goes through the states of being susceptible (s), infected (i), and recovered or removed (r). the standard sir model is governed by two parametersinfection rate β and recovery rate γ. to incorporate the prevention strategies and its dynamic changes into the model, we further add a prevention parameter r into the model. thus, in our model β is interpreted as the probability that when a susceptible individual interacts with an already infected individual in a time unit, the susceptible individual gets infected from the latter, and γ is the probability that an infected individual recovers from the disease in a time unit, while r is the number of individuals one infected individual would interact with in one time unit. it is important to remark that in our model, β and γ are the intrinsic properties of the virus, and it is not affected by the prevention measures, while r is affected by the prevention measures -r will be smaller if the city imposes higher level of prevention measures and people exercise social distancing, and r is larger if the city relaxes its prevention measures. the combined rβ would correspond to the β parameter in the standard sir model. then, the differential equations of the single-city model are as follows: where s is the susceptible population, i is the infected population, r is the recovered population, n is the total population of the city, and t is the time. note that s, i, r are considered variables that change over time, while n remains the same over time. equation ( ) can be interpreted as the change of s in a time unit dt due to the fact that each infected individual meets r individuals, among them a fraction of s/n are susceptibles, and thus β fraction of them will be infected and change from s state to i state, and since we have i infected individuals, the total decrease on s is rβis n . equation ( ) is simply because there are currently i infected individuals and γ fraction of them would be recovered in each time unit dt, and equation ( ) is the combined effect of the other two equations. we extend the single-city model to multiple cities where different cities may impose different levels of prevention measures and there are population movement between the cities. in the multi-city model, there are m cities. for each city i, we use subscript i in s i , i i , r i , n i and r i to represent the sir variables and parameters. note that β and γ are the same across cities since they model the intrinsic characteristics of the virus, while the prevention parameter r i 's are different across different cities, modeling different prevention measures taken among the cities. in the real world, the population base of a city is usually stable over time. thus, we would like our model to maintain the population for city i, n i , the same over time, which also simplifies our model analysis. however, with different population mobility between cities, it is not trivial to maintain population balance in the multi-city model. to achieve this, we introduce the external environment as the background that could counter balance the excess or deficit of population of each city due to the population movement. the external environment could be viewed as other cities that suppose that each city i has a floating population f i , which is a fraction of the total population who will move in or out of the city in a time unit. let f i,j be the population moving from city i and city j in a time unit, and f i, be the population moving between the city i to the external environment in a time unit. thus, we have f i = m j= ,j =i f i,j . we use the following rules to govern the inter-city population movement: ( ) between two cities, the two directional movement population is balanced, i.e. f i,j = f j,i ; and ( ) the population movements from one city i to two different cities j and j are proportional to the two destination cities' floating populations, i.e. f i,j /f i,j = f j /f j . to realize the actual values of the population movement, we use the following simple procedure: we first sort the floating population f i from the smallest to the largest, and determine the population movement of each city in this order (without loss of generality, assuming f ≤ f ≤ · · · ). for the city with the smallest floating population, we first allocate a fixed fraction (e.g. %) of the floating population as the exchange population with the external environment to ensure that every city has population exchange with the environment, and the remaining floating population is allocated to f ,j proportional to the city j's floating population f j , according to rule ( ) above. then for each remaining city i in the order, we first apply rule ( ) above to fix the f i,j = f j,i for all j < i, and then apply rule ( ) on the remaining cities j > i to get f i,j proportional to f j , and finally for the left over population f i − m j= ,j =i f i,j , we assign it to the exchange population with the environment f i, . figure shows a concrete example of the procedure. (a) the floating population of city a, city b and city c is , and thousand respectively. first of all, the floating population between city c and other cities is calculated, with % floating population (i.e. , ) exchanges with the environment, and the remaining %, or , is allocated among moving populations to city a and city b. based on the population proportion, movement to city b accounts for %, which is , , and movement to city a is , . (b) then we calculate the city b with the second smallest floating population. the floating population between city b and city c is , , and the ratio of floating population between city c and city a is : . therefore, the proportion of floating population between city b and city c and between city b and city a is also : . the floating population between city b and city a is , , and the remaining , are between city b and the external environment. (c) similarly, the remaining , floating population in city a will be used as the floating population with the external environment. with the above rules of population mobility, the population base of each city remains unchanged, and the cities with more floating population account for a larger proportion of the floating population in other cities. we now combine the single-city sir model with the mobility rules defined in the previous section. with the rules of population mobility and the external environment, we can ensure the dynamic balance of population mobility in multiple cities in the model. by adding the part of floating population to the single-city model, we get the multi-city model with the following equations: where m for the total number of cities, represents the external environment, and ∼ m represent the cities. the explanation of the above equations should be straightforward. for example, for eq. ( ), besides the virus infection within the city given by the term riβiisi ni same as in eq.( ), we also account for movements between the cities: for every j = i, f i,j s i /n i is the number of susceptible individuals moving out of city i to city j, assuming that the mobile population has the same fraction of susceptible individuals as the general city population; and f i,j s j /n j is the number of susceptible individuals moving into city i from city j. the other equations have the similar explanation. from the model, in particular eq. ( ), we can see that if city j has a higher portion of infected people than city i, i.e., i j /n j > i i /n i , then city j contributes the inflow of infected to city i, and vice versa. this matches the intuition of virus propagates from highly infected cities to lowly infected cities. during the epidemic, different cities or regions may have different strategies and measures to deal with infectious diseases. for example, during the covid- outbreak, some regions impose mandatory mask wearings while some do not, many enforce social distancing, but at different scales, such as limited the size of gathering of no more than or people, closing schools, or restricting travels to and from high risk regions. all these restrictions can be reflected into two parameter changes within our model. first is the prevention parameter r i for each city i. different social distancing measures essentially all reduce the number of people any individual would meet in a time unit, which is modeled by r i . thus we use r i to model the prevention measures, with lower r i meaning high level of prevention measures and high r i meaning low level of prevention measures. another parameter affected by the prevention measure is the fraction of the floating population f i /n i of each city i, denoted as p i -a higher prevention level decreases the fraction of the floating population while a lower prevention level increases the fraction of the floating population. most cities or regions also dynamically adapt their prevention measures based on the current infection data -when the new infection cases rise the prevention measures intensifies, and when the number of new cases drops, the prevention measures is relaxed. we model this scenario by setting an prevention threshold and dynamically change the prevention parameter r i and the fraction of the floating population p i based on whether the current infection cases is below or above the prevention threshold. technically, we have three main factors for deciding and changing the prevention measures: ( ) prevention threshold θ, which sets a limit on the number of new infections within a time period. new infections only include new cases caused by intra-city infections, excluding imported cases brought outside the city. when the new number of infected people each day for consecutive days is lower than the prevention threshold, it shows that the epidemic situation is getting under control, and the prevention intensity begin to decline (r increases). when the number of new infected people in any given day is higher than the prevention threshold, it shows that the epidemic may worsen again, and prevention intensity begin to rise (r decreases). ( ) the range of changing prevention intensity [r l , r h ] and [p l , p h ], which gives the range of changes of each prevention parameter r i and the fraction of floating population parameter p i . when the prevention measure intensifies, the values are changed to r l and p l respectively, and when the prevention measure relaxes, the values are changed to r h and p h . ( ) the speed of the change in prevention intensity, as measured by the number of days k to complete the change. in the real world, the change of prevention measures never happens instantaneously and it takes some time. so we use k to model the number of days needed to change r l to r h and p l to p h , or in the reverse order. we use the geometric sequence to implement such change sequences, as given below: where t represents days and s represents the direction of change in prevention. when s = , it means that the prevention intensity is reduced. when s = , it means that prevention intensity is strengthened. the prevention intensity r and the proportion of floating population p are always within the range of the prevention strategy. in the multi-city model, the initial conditions of the three cities a, b and c are all ic = ( , . %), while the initial condition of the external environment is ic = ( , . %). notations r and p represent the constant prevention intensity and the constant proportion of population mobility, respectively. for adaptive strategies, r indicates the initial prevention intensity, while rl and rh indicate the lower limit and upper limit of the prevention intensity, respectively; p indicates the initial proportion of population mobility, while pl and ph represent the lower and upper limits of the proportion of population mobility, respectively; θ represents the prevention threshold, and k represents the speed of the change in prevention intensity. in general, prevention strategies can be summarized like in table . ps is the case that the prevention intensity remains unchanged: the parameters of prevention intensity r and the proportion of floating population p are fixed values, and there is no prevention threshold and reaction speed. this corresponds to the classical infectious disease model, and we refer to it as a model with a constant prevention strategy. ps corresponds to the adaptive changes in prevention intensity that we commonly see during the covid- pandemic: the full strategy is characterized by the prevention threshold θ, the r-range [r l , r h ], the p-range [p l , p h ], and the change speed k, and we refer to such ones as models with an adaptive prevention strategy. in the next section, we will empirically evaluate our models to discover the key phenomenon of epidemic plateau, and validate it against the real-world covid- data. we will then provide theoretical analysis on the plateau phenomenon in section . based on the above epidemic model with prevention strategy, we take the covid- as an example to simulate the epidemic development in a single city and in multiple cities. we will use one day as the time unit for the model given in the previous section. we base the choice of our parameters on the research that have been made on the covid- . the first parameters are the infection rate and the recovery rate of covid- . a person stays infected by covid- for . days on average [ ] . the recovery rate is thus defined as γ = / . = . . for the infection rate of covid- , we use the most common indicator in the epidemic research, the reproduction number to calculate. the reproduction number can be divided into basic reproduction number and effective reproduction number. the basic reproduction number represents the average number of people infected in a group of all susceptible people before an infected person recovers, expressed as r . the estimation of the basic reproduction number is generally chosen in the early stage of the outbreak, as the proportion of susceptible people in the population is close to . the effective reproduction number is different from the basic reproduction number, and it represents the average number of people infected at time t with a certain proportion of the susceptible population before an infected person recovers, expressed as r t . the effective reproductive number r t will change over time, because the proportion of susceptible people will change with the development of the epidemic. when the effective reproduction number r t < , it indicates that the epidemic is receding and will die out soon. the time from infection to the recovery from the infection is an infection cycle, which is γ days. before recovering, the infected person will come into contact with r individuals every day. among these people, only susceptible people will be infected, and the probability of each susceptible individual getting infected is β. therefore, the basic reproductive number r and the effective reproductive number r t have the following relationship with infection rate β and recovery rate γ: we can get the infection rate β of covid- through the basic reproduction number r of sars-cov- and the number of human contact r as in eq. ( ). before calculating the infection rate β, it is necessary to know the prevention parameter r, or the number of human contacts per day. as discussed before r will change according to the prevention measures. the basic reproduction number r should corresponds to the situation of the early stage of the outbreak before prevention. at this time, the proportion of susceptible people is close to , and the number of contacts with the population is at the normal level. in order to better estimate the number of human contacts, we used the epidemic data provided by the information center of shenzhen public security bureau. in shenzhen, for people infected with covid- , the public security bureau will track down the people who have been in contact with him during the incubation period and conduct medical observation to avoid further spreading. the public security bureau records the number of contacts tracked every day and refers to the number of people obtained as the number of medical observers. based on the number of daily medical observations, divided by the product of the number of new diagnoses per day and the incubation period ( . days), we estimate the normal number of contacts among people r = . in order to make the results closer to the normal number of human contact, the data from the early stage of the epidemic (the first days of the outbreak in shenzhen) were selected in the experiment. there are some estimates of the basic reproduction number r in the articles about covid- , and the results are all around [ , , , , ] . assuming that the basic reproduction number of sars-cov- r = , combined with the recovery rate γ = . and the contact times of the population r = , the infection rate of covid- can be obtained as β = . from eq. ( ). as derived above, r = is the number of contacts without prevention. the prevention strategies would reduce r. only when the effective reproduction number r t < , the epidemic begins to subside, and the number of infections declines. we call the number r that corresponds to r t = asr t , the effective prevention intensity, which corresponds to the effective reproduction number r t according to eq. ( ) . based on eq. ( ) and the calculated infection rate and recovery rate from above, we can obtain that the number of infections will decrease immediately when the prevention intensity r < . with the assistance of the information center of shenzhen public security bureau, the population mobility ratio p is estimated according to the population mobility data of shenzhen in and . during the outbreak of covid- in , shenzhen implemented strict restrictions on population mobility, and the proportion of population mobility was around %. in the same period in , the proportion of people moving fluctuated between % and %. in this paper, it is assumed that the proportion of population mobility under normal conditions is p = %. in the simulation experiment, the total population and the proportion of initial infected people in the city are called initial conditions. different initial conditions will appear in the single-city model and the multi-city model. an initial condition can be expressed as ic = (n, i n ). figure shows the development of the epidemic in single city and multiple cities with constant or adaptive prevention strategies. the y-axis is the value of i for a particular day, which is the number of current existing infected individuals that can still transmit the disease (note that it is not the number of newly infected cases in that day). as a convention, for a constant prevention strategy that does not change r, e.g. r is always , we denote it as r = in the figure legend; for an adaptive prevention strategy, if we initially set a prevention strategy to be at a certain level e.g. , and then it will change in the range [r l , r h ] when the newly infected case per day drops below the threshold, we denote it as r = and r l , r h to the appropriate values in the legend. the fraction of floating parameter p and the corresponding p and p l , p h are treated in the same manner. the results from figure are as follows. • figure (a): in the single-city model with a constant prevention strategy, the change curve of the number of existing infections is smooth. the number of infections either continues to decline (r ≤ ), or rises first and then falls (r > ). • figure (b): in the single-city model with an adaptive prevention strategy, the change curve of the number of existing infections is no longer smooth. comparing to the single-city model with a constant prevention strategy (figure (a) ), it has a distinctive feature -a long period in which the number of existing infected people remains more or less the same, with small fluctuations. we refer to such a flat period a plateau, and it is the main phenomenon we are going to study in this paper. • figure (c): this is the three city case and all cities have constant prevention strategies. in the multi-city model, it can be found that the urban epidemic situation affects each other under the influence of population mobility. the number of infections in city c should have risen to a higher level (i > ), but instead it begins to decline earlier under the influence of other cities. on the contrary, there has been an increase in the number of infections in the external environment ee which should have been declining (r = ). there is no plateau phenomenon in this case. • figure (d): in this case, two of the cities (b and c) adopt adaptive prevention strategies, and one city (a) as well as the external environment use a constant prevention strategy. the phenomenon of horizontal fluctuation in the number of existing infections, i.e. the plateau, appears again. more interestingly, the plateau appears in every city, has occurred in every city and the environment, even if some city and the environment adopt a constant prevention strategy. as shown in figure , in some cases we see that the phenomenon of plateau may occur, that is, there is a prolonged period in which the number of existing infections maintains at the same level with small fluctuations. the plateau means that there will be a prolonged period in which the infection within the population will be maintained at the steady level. we will see in the next subsection that indeed we could observe such plateau phenomenon in the real-world covid- epidemic. the emergence and the properties of such plateaus are certainly important for the public health authorities to devise appropriate policies to battle against the covid- pandemic. in this section, we will use empirical observations to extract the possible conditions for the emergence of the plateau and its properties, and in section , we will provide theoretical analysis to validate these observations. first, from figure , we can see that the adoption of adaptive prevention strategies is strongly correlated to the emergence of the plateau. when there is no adaptive prevention strategies deployed, we do not see the plateau phenomenon. however, the adoption of adaptive strategies itself is not sufficient to guarantee the appearance of the plateau, which can be seen in the blue curve in figure (b) . moreover, in the multi-city situation, even if some city does not adopt an adaptive prevention strategy, it still exhibits a plateau (city a in figure (d)), seemingly under the influence from other cities with adaptive prevention strategies. thus, the actual condition of the emergence of plateau needs to be further analyzed. second, the height of the plateau is different with different adaptive prevention strategies. in the next test, we will try different prevention strategies parameters to empirically verify the factors that affect the height of the plateau. from figure , we can see that the adaptive prevention strategies affect the appearance of the plateau. now we also try different prevention parameters to see their effect on the plateau, especially on the height of the plateau. we use single-city model for this test to make the effect of prevention strategies more direct. as stated in section . , in the single-city model, an adaptive prevention strategy consists of parameters of prevention threshold θ, range of prevention intensity [r l , r h ] and the speed of change k in the number of days to switch the prevention intensity. we now analyze the effect of each of these parameters. figure a , when there is a plateau in the development of the epidemic, it can be found that the prevention threshold θ is positively correlated with the height of the plateau. the greater the prevention threshold, the higher the plateau. a closer look at their relationship, one may even see a close to linear relationship between the prevention threshold and the height of the plateau. we will validate this relationship in the theoretical analysis section. in addition, the higher the plateau, the greater the daily fluctuation of the number of existing infections, but in general it still remains at a certain level. the range of changing prevention intensity [r l , r h ]. as shown in figure b , when there is a plateau in the development of the epidemic, different [r l , r h ] will not change the height of the plateau. however, [r l , r h ] will determine whether the plateau occurs. when both r l and r h are small, the plateau does not occur, and the number of existing infections continues is declining (see the red line). when both r l and r h are large, the number of existing infections will rise at first and then decrease, but there will still be a plateau in the end (see the yellow line). the size of the changing range does not affect the height of the plateau, but it is related to the amplitude. the greater the range of change, the greater the amplitude (compare the blue line with the purple line). the speed of the change in prevention intensity k. figure c shows that k does not affect the height of the plateau, but it does affect the fluctuation amplitude of the plateau. the smaller the k, the greater the fluctuation of the number of existing infections during the plateau (compare the blue line with the purple line). through our simulations, we can see that the emergence of plateau is related to the range of changing prevention intensity [r l , r h ], and the height of plateau is positively correlated with prevention threshold θ. it shows that the integration of prevention strategies, especially the adaptive ones, would change the dynamics of the epidemic that is not covered by the traditional epidemic models. the plateau and its related phenomenon is actually more consistent with what happens in the real world for the covid- pandemic, as we illustrate in section . . as shown in figure d , it is found that the platform period also exists in the multi-city model. through simulation and empirical observation, we found the following phenomena. • the height of plateaus change from the single-city model: in the multi-city model, if all cities have the same ic and adopt adaptive prevention strategies, they all have a plateau, but the height of the plateau is different from that of the single-city model. comparing figure (a) with figure a , the height of the plateau of city a decreased, while that of city c increased. the reason is due to the population mobility in the multi-city model. as the proportion of infected people in city a is the highest, the outflow of infected people is larger than the inflow, and the number of infected people in city a will decrease, i.e. the height of the plateau of city a will decrease. city c is the opposite. • cities that would not have a plateau by itself could have a plateau in the multi-city model: cities with constant prevention strategies could also enter a plateau period in the multi-city model. in figure city c adopt constant prevention strategy, in which the number of infections in city a should rise at first and then decline, and the number of infections in city c should be declining all the time, as shown in figure a . however, under the influence of population mobility and city b, every city has entered a plateau. we infer that in the multi-city model, one city have plateau, then it is possible to lead other cities to enter the plateau period. • either all cities are in the plateau or none of them is in the plateau: in the multi-city model, comparing figure (c) with figure a & b, we find that the epidemic development in cities is not independent. either every city has entered a plateau(see figure a & b) , or every city keeps receding without a plateau after their initial peaks. the above observations show that quite interesting plateau phenomenon emerges even in the multi-city model with complex epidemic dynamics within cities and population mobility dynamics cross cities. in particular, the results strongly indicate that all cities are interdependent in terms of the epidemic development -their plateau phenomenon co-occur, and even a city that would not have a plateau by itself would enter a plateau under the influence from the adaptive strategies of other cities. this suggests that in battling the covid- pandemic, one should not look only at the local prevention strategies, but also need to take into account other regions's strategies and population mobility, and perhaps some global coordination would be more effective. the pateau phenomenon also appears in the real world epidemic, in particular in the current covid- pandemic. we collect the epidemic data from the total of countries from data source dxy , which collects data from sources including the world health organization (who), with data up to the date of october , . we visually investigated the data and found that there are countries that have demonstrated clear plateau phenomenon for more than one month. among other countries, of them are still suffering worsening situations or are facing a new rising of the epidemics, and countries have receding epidemic. the basic statistics are summarized in the following table. figure shows a few examples of countries that have a clear plateau phenomenon, including thailan, south korea, tajikstan and qatar. these data clearly support the existence of the plateau phenomenon in practice, which means it is important for us to study in more details on the plateau phenomemon. although it may be difficult to pin point the exact reasons that cause the plateau phenomenon for each country, from our simulation result observations, we believe that the plateau phenomenon in these countries is likely related to the adaptive prevention strategies adopted by the countries. for the majority of countries that are still experiencing worsening covid- epidemic, if proper adaptive prevention strategies are enforced, we could expect that they will also enter the plateau period in the future. thus, understanding the plateau phenomenon would be useful for most countries that are suffering the covid- epidemic. in the next section, we will provide theoretical analysis on the plateau phenomenon. in the simulation study, we found that epidemic development might enter a plateau period after sir model is integrated with an adaptive prevention strategy. the simulation study suggests some simple relationships such as the emergence of plateau is related to the changing range of prevention intensity [r l , r h ], and the height of plateau is positively correlated with the prevention threshold θ. in this section, we will analyze theoretically the conditions of the emergence and ending of the plateau as well as the properties of the plateau. our analysis focus on the single-city model. the multi-city model involves much more complicated dynamics due to the mobile populations between the cities and we will leave its theoretical analysis as a future work item. as suggested from the simulation study, the plateau is related to the adaptive prevention strategy, but it is also the case that not every prevention strategy would generate a plateau (see figure b) . a closer investigation shows that this is related to the effective prevention intensityr t , as defined in section . . . recall that the effective prevention intensitỹ r t is the value of prevention intensity r when the effective reproduction number r t takes the value of . intuitively, when r t = , the number of infections an infected individual makes before he/she is recovered is exactly , meaning that the number of existing infected cases would remain the same. thus,r t is the corresponding prevention intensity level that would maintain the infection cases the same. note that in general the effective prevention intensityr t is different from the actual value of the prevention intensity r used: the former is the would-be value to keep the infection cases the same while the latter is the actual value of the prevention strategy used at each day, and this is also the reason we use different notations to distinguish the two. the effective prevention intensityr t has the following simple but important property: the effective prevention intensityr t is monotonically increasing with time t. proof by eq. ( ), and the factr t is defined as the value of r when r t = , we havẽ since the number of susceptible people s is monotonically decreasing with time t while other parameters n, β, γ stay constant, we have thatr t is monotonically increasing. in the single-city model summarized in section , we have several aspects that try to reflect the real-world scenario, such as the day grace period before relaxing the prevention intensity, and the changing of the strategies taking some time governed by parameter k. to emphasize the essence of the model, for the theoretical analysis, we consider the following simplified ideal single-city model, which is consistent with the principle of full model . in the ideal model, once the daily new cases drop to the prevention threshold θ, we immediately adjust the prevention strategy r such that we keep the daily new cases to be exactly θ, as long as we have r ≤ r h . moreover, we assume that the city starts with a significant number of infected cases and under intense prevention control, and thus the prevention strategy is relaxed when the infection cases drop below the prevention threshold. technically we require that the initial infection number i satisfies i · γ > θ, that is, the number of daily infected people initially is i · γ and it is more than θ. this corresponds to the real-world scenario where the prevention strategies are only employed after the epidemic outbreak already begins, and the adaptive strategies are designed to maintain the infection cases at a low level after the initial infection peak already occurs. note that the above description on the ideal model only applies to the adaptive prevention strategy. the constant prevention strategy remains the same in the ideal model. we will also use the simulation results from the full model to validate the accuracy of the prediction from the ideal model. we first investigate the conditions for the presence or the absence of the plateau, in the single-city model. let t θ be the time when the number of daily recovered people drops to θ, i.e. iγ = θ. recall that we assume that initially i γ > θ, and thus i will eventually drop to θ. with lemma , we can derive the following result connecting the effective prevention intensity with the plateau phenomenon. theorem in the ideal single-city model with an adaptive prevention strategy, at any time t, if the effective prevention intensity at this timer t ≥ r h , then there will be no plateau after time t. on the other hand, ifr t θ < r h , then there will be a plateau starting at t θ . proof (proof (sketch)) whenr t ≥ r h , we know that for any time t > t,r t >r t according to lemma . this means that for all time t > t, the actual prevention intensity r as the property that r ≤ r h <r t . sincer t corresponds to the effective reproduction number r t = , this implies that r t < by eq. ( ) , which in turn implies that for all time t > t, the number of new infections any infected people would generate is less than , and the epidemic will keep receding. now suppose thatr t θ < r h . according to the definition ofr t θ , at time t θ iγ = θ. let t be the time when the daily infected people first hits θ. by our assumption, at time t the infected people i is dropping from i with i γ > θ. thus at time t iγ > θ since in the days before θ, the daily infected people must be greater than θ. this means t < t θ . this implies that before time t θ the ideal model would already adjust r to keep the daily infection number as θ. the conditionr t θ < r h guarantees that it can keep the daily infection number as θ to time t θ , at which the daily infection number balances with the daily recovery number iγ. from time t θ on, we can always keep the prevention intensity r as r t until it increases to r h . during this period, the daily infection and daily recover balance each other, and we have the plateau. the above theorem shows that the relationship of the effective prevention intensityr t and the upper bound of the prevention intensity range r h directly determine the presence of the plateau. note that for a constant prevention strategy with a fixed value r, it is clear that it has no plateau because it is essentially the same as the standard sir model. therefore, we can obtain the following conclusion on the emergence and the ending of the plateau. corollary (condition for the emergence of the plateau) in the ideal single-city model, the condition that the plateau will emerge is that we use an adaptive prevention strategy andr t θ < r h . corollary (condition for the ending of the plateau) in the ideal single-city model, given that there is a plateau at time t, the plateau period will end at time t > t whenr t ≥ r h . corollary states that we will have a plateau when the effective prevention intensity is still less than r h when the daily recovery number hit the prevention threshold, while corollary states that when it happens, the plateau will end once the effective prevent intensity reaches r h . we defer the discussion on the actual calculation of the conditionr t θ < r h to section . when we study the length of the plateau. we use simulation results shown in figure to validate these conditions in our actual model. figure a shows the epidemic development under two adaptive prevention strategies. the first strategy, shown in the blue curve, has a clear plateau period. in figure b , we show the corresponding changes of the effective prevention intensity and the actual prevention intensity. for the blue curve in figure a , the blue curve in figure b shows the corresponding changes in the actual prevention intensity r, which fluctuates between r l = and r h = for a period of time. during this period, the yellow curve, corresponding to the effective prevention intensityr t, of the first strategy increases gradually from to . since θ = and γ = . , when y-axis i is about / . ≈ , the corresponding the effective prevention intensity is around , which is less than r h = , which is consistent with corollary that the plateau would appear. whenr t, increases to = r h , we can see that the plateau ends in the corresponding blue curve on the left. now, for the second strategy, the red curve in figure a , we see that there is no plateau. the actual prevention intensity r keeps at the level r h = in this case (the red curve in figure b ), while the effective prevention intensityr t, starts at and increases slowly above (the purple curve in figure b ). this is also consistent with corollary , meaning that wheñ r t θ ≥ r h = , there will be no plateau in this case. although the number of infected people in the plateau period has small fluctuations, it is basically maintained at a same value. we call the value around which the number of existing infections fluctuates is the height of the plateau, and denote it as i p . in the ideal model, the height of the plateau i p is when the number of existing infected people does not change, that is, when the effective reproduction number r t = . using the relations we derived before, we can obtain the following result on i p . theorem in the ideal single-city model, the height of the plateau is given as follows: where θ is the prevention threshold and γ is the recovery rate. proof in the ideal model, in the plateau we have r t = , and the daily newly infected people is exactly equal to the prevention threshold θ. according to the sir model the daily newly infected people is rβis n (excluding the number of recovered people), and thus in the plateau period, from eq. ( ), and setting r t = , we know that rβs n = γ. plugging it into eq.( ), we have i p = θ/γ. theorem directly shows that the height of the plateau has positive linear relationship with the prevention threshold θ, and it is not related to the other parameters such as the range of prevention strategy [r l , r h ] or the speed of prevention k. this result is consistent with our simulation study findings (see figure ). in particular, comparing with figure a , when we plug in θ = , , , with γ = . , we obtain the theoretical heights as i p = , , , , while the empirical averages we obtain the simulation results are , , , respectively, indicating that the theoretical results match with the simulation results reasonably well. the reason that the empirical results are consistently lower than the theoretical predictions is because in our actual model, we have an asymmetric strategy adjustment: we need consecutive days of new cases dropping below θ to relax the prevention, while we only need one day of new cases rising above θ to strengthen the prevention. this asymmetric control push the actual height lower than our theoretical prediction from the ideal model. after obtaining the height of the plateau i p , we can further calculate the length of the plateau by the area method. we denote the length of the plateau, i.e. the time period from when the plateau begins to the plateau ends, as t . it is clear that t · i p is the area covered under the plateau period. so, we just need to calculate the area underlying the plateau to get t . the result is given in the following theorem. theorem in the ideal single-city model, assuming that the number of new infections falls to θ is the beginning of the plateau period, the length of the plateau is given as follows: where s e is the number of susceptible people when the plateau ends, and s e = γn βr h , and s b is the number of susceptible people when the plateau begins, and it is the solution of the following equality where s , i are the number of susceptible and infected people when the time starts, and r is the initial prevention intensity used before the prevention intensity is adjusted in the range [r l , r h ]. proof (proof (sketch)) in the curve with i as y-axis and time as x-axis, the area under curve (auc) by time t is the cumulative existing infected people by time t. on average, each infected individual takes /γ time to recover, so each infected individual is counted /γ times. therefore, the auc by time t is the total number of once infected people multiplied by /γ, which is (i + r)/γ. since s + i + r = n , so we have the auc by time t is (n − s)/γ. let t b , t e be the time when the plateau begins and ends, and correspondingly s b and s e are the numbers of susceptible people at time t b and t e respectively. then we have the auc between t b and t e is ( we now show how to derive s b and s e . first, for s e , we know from corollary that when the plateau ends,r t e = r h , and by the definition ofr t e , we know r t e = . plugging these values into eq. ( ), we obtain that s e = γn βr h . to derive the result for s b , we rely on the equation below connecting i and s in the sir model [ ] : where s , i are the numbers of susceptible and infected people when the time starts. before entering the plateau period, the prevention intensity r is fixed to a value r . when it first hits the pateau period, i is equal to i p . thus, when plugging i = i p and r = r into the above equation, we obtain eq. ( ) , and s b is the solution of this equation. note that s b derived from eq. ( ) can be used to test conditionr t θ < r h in corollary :r t θ = n ·γ s b ·β according to eq.( ). we now validate theorem with the empirical results. we compare our theoretical prediction on the plateau length with the empirical results from figure a , with the initial condition ic = ( , . %) and parameters r = , r l = , r h = , k = and θ from to . table summarizes the comparison result. we can see that the theoretical and empirical results match reasonably well. moreover, the estimation error is mainly from the error in the estimation of the height -if we replace the theoretical heights with the empirical heights, we get much closer estimates of , , , respectively, which means our theoretical auc prediction is quite accurate. in this paper we study a phenomenon of epidemic development: covid- plateau. this phenomenon is formed under the change of prevention intensity of adaptive prevention strategies. in the traditional infectious disease model, it is difficult to find the existence of the plateau. we investigate empirically from both simulations and real-world data and on the plateau phenomenon, in both single-city models and multi-city models, and further provide theoretical analysis in the single-city model and obtain an number of results on the emergence and the characteristics of the plateau phenomenon. our results also suggest that all regions are interconnected and local prevention strategies would have effects to other regions as well. understanding the plateau phenomenon would be useful for most countries that are suffering the covid- epidemic. there could be some future work along this direction. on the empirical side, one could investigate in more detail the real-world plateau phenomenon and their correlations with specific prevention strategies used. on the theoretical side, the multi-city model is much more challenging due to the complicated population mobility dynamics, and it would be very important and beneficial to obtain some insightful results in the multi-city model. we hope that our findings could help the understanding of the covid- pandemic (and other epidemics as well) in connection with different prevention strategies, and assist policy makers in predicting the effect of their prevention strategies. nowcasting and forecasting the potential domestic and international spread of the -ncov outbreak originating in wuhan, china: a modelling study reconstruction of the full transmission dynamics of covid- in wuhan preliminary prediction of the basic reproduction number of the wuhan novel coronavirus -ncov incorporating human movement data to improve epidemiological estimates for -ncov. medrxiv chernet tuge deressa and gemechis file duressa. modeling and optimal control analysis of transmission dynamics of covid- : the case of ethiopia clinical characteristics of novel coronavirus infection in china serial interval of sars-cov- was shortened over time by nonpharmaceutical interventions the duration of infectiousness of 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a mechanistic disease model exploring dependence of covid- on environmental factors and spread prediction in india predicting covid- trends in canada: a tale of four models comparing the accuracy of several network-based covid- prediction algorithms an investigation of transmission control measures during the first days of the covid- epidemic in china effects of proactive social distancing on covid- outbreaks in cities, china. emerging infectious diseases the role of environmental factors on transmission rates of the covid- outbreak: an initial assessment in two spatial scales mathematical modeling and research on dynamics of infectious diseases key: cord- - iejckwx authors: yen, muh-yong; wu, tsung-shu joseph; chiu, allen wen-hsiang; wong, wing-wai; wang, po-en; chan, ta-chien; king, chwan-chuen title: taipei's use of a multi-channel mass risk communication program to rapidly reverse an epidemic of highly communicable disease date: - - journal: plos one doi: . /journal.pone. sha: doc_id: cord_uid: iejckwx background: in september , an outbreak of acute hemorrhagic conjunctivitis (ahc) occurred in keelung city and spread to taipei city. in response to the epidemic, a new crisis management program was implemented and tested in taipei. methodology and principal findings: having noticed that transmission surged on weekends during the keelung epidemic, taipei city launched a multi-channel mass risk communications program that included short message service (sms) messages sent directly to approximately . million taipei residents on friday, october th, . the public was told to keep symptomatic students from schools and was provided guidelines for preventing the spread of the disease at home. epidemiological characteristics of taipei's outbreak were analyzed from sampled ahc cases. median time from exposure to onset of the disease was day. this was significantly shorter for cases occurring in family clusters than in class clusters (mean±sd: . ± . vs. . ± . days, p = . ), as well as for cases occurring in larger family clusters as opposed to smaller ones ( . ± . days vs. . ± . days, p< . ). taipei's program had a significant impact on patient compliance. home confinement of symptomatic children increased from % to % (p< . ) and helped curb the spread of ahc. taipei experienced a rapid decrease in ahc cases between the friday of the sms announcement and the following monday, october , ( . % vs. . %). by october , ahc cases reduced to . %. the success of this risk communication program in taipei (as compared to keelung) is further reflected through rapid improvements in three epidemic indicators: ( ) significantly lower crude attack rates ( . % vs. . %, p< . ), ( ) a short epidemic period of ahc ( vs. days), and ( ) a quick drop in risk level ( ∼ weeks) in taipei districts that border keelung (the original domestic epicenter). conclusions and significance: the timely launch of this systematic, communication-based intervention proved effective at preventing a dangerous spike in ahc and was able to bring this high-risk disease under control. we recommend that public health officials incorporate similar methods into existing guidelines for preventing pandemic influenza and other emerging infectious diseases. the viral illness known as acute hemorrhagic conjunctivitis (ahc) is frequently accompanied by a highly transmissible acute eye infection. this infection is most often caused by the adenovirus, enterovirus , and coxsackie's virus. coxsackie a infection was first reported in in ghana and has since appeared around the world [ , , , , ] . since late , several ahc epidemics have occurred in asian countries such as korea, malaysia, and singapore [ , , ] . in september , southern china's coxsackie a ahc epidemic spread to hong kong after first appearing on the mainland in early summer. on september th, a cluster of cases with ahc-like symptoms was first unofficially reported by the media in keelung, a harbor city bordering taipei ( km away from hong kong), in northern taiwan. because ahc was not on taiwan's list of reported communicable diseases at the time, it was difficult for public health officials to collect adequate epidemiological data until october th, when a dramatic spike in ahc cases was reported by the mass media. at that time, the keelung department of health reported cases of pink eye disease among public school students. although general control measures were taken, case numbers continued to increase rapidly in keelung, particularly during weekends. also on oct. th, taipei city department of health was alerted to its first ahc cluster ( cases from a primary school) in neihu, a taipei district neighboring keelung (figure ). taipei was more prepared for the ahc outbreak as its alertness was raised by media coverage of outbreaks in nearby keelung. the local department of health was also able to identify clusters quickly because it had made school reporting of influenza-like illness clusters (or other unusual clinical presentations) a mandatory practice since . taipei's department of health had reorganized its disease control and prevention system against emerging infectious diseases (eid) after 's severe acute respiratory syndrome (sars) epidemic but had not yet tested the system under real life circumstances. in launching countermeasures to bring the ahc outbreak under control, the taipei department of health was also able to test its system and fine-tune its public health response for future eids. to evaluate the effectiveness of these intervention measures, daily surveillance was conducted to analyze the incidence rate and temporal-spatial distribution of new ahc cases. in addition, students' parents were sent questionnaires to capture their experience with these preventative measures. taipei city, the largest city in taiwan, is located in northern taiwan and directly borders keelung city ( figure ). in , taipei, a city of . million people occupying . km , had a student population of , ( . %). taipei city has a larger population size and density than neighboring keelung city (table ) , and is, thus, exceedingly vulnerable to microbial transmission and eid outbreaks. this study was approved by the advisory committee for infectious diseases control of taipei city's department of health, taipei city government. informed consent was obtained from the parents of participating schoolchildren in writing before they were asked to complete the questionnaire (file s ). in response to a large outbreak of sars in , taipei's department of heath established a new crisis management system with the goals of detecting eids early, implementing appropriate and timely public health responses, and administering effective risk management [ , ] . at the start of taiwan's ahc outbreak, local health departments in all of taiwan's cities were engaged in a passive surveillance system in which schools reported cases as they occurred. on october th, taipei's department of health urged schools and kindergartens with clusters of more than three ahc cases to actively report cases to the local department of health twice weekly. agespecific incidence rates of ahc among school-aged children during the outbreak were also calculated using the collected surveillance data. when total ahc cases in taipei reached close to on october , , an active school-based surveillance system was launched by the city to monitor trends in the spread of ahc and evaluate the effectiveness of intervention measures. schools were required to make daily reports to taipei's department of education, regardless of whether there were any new cases on a given day. as the incidence rate of the last reported ahc cases in keelung (on october ) was . %, we set this rate as a cut-off point for comparing the effectiveness of the countermeasures used by the two cities. tailing data, i.e., data that fell below the . % incidence rate was excluded from our analysis. we used this cut-off to define the duration of the ahc epidemics for both cities. according to our definition, the ahc epidemics for each city began from the date of the first reported cluster and ended on the date that rates of new case incidence dropped to . % or below. epidemiological design and data analysis . study subjects. we analyzed reported ahc cases from ten taipei schools (totaling , students). students from six of the ten schools, three elementary schools and three junior high schools, made up most of the reported ahc case numbers. two elementary schools and two junior high schools that were also included in the research reported continuous ahc occurrences during the week that our field epidemiological study was conducted. for each of the ten schools, we randomly selected one class that had had occurrences of ahc and one class where there had been no occurrence of ahc as our case and control groups, respectively. data collected from these individual school groupings were gathered and divided into one study and one control group for data analysis. . case definition of ahc and clusters (family, school). the ahc cases in this study all involved an acute conjunctiva inflammation that included eye redness (pink eye) accompanied with pain, swelling, tearing, or discharge from one or both eyes. family clusters were defined as two or more cases of ahc occurring in one family within days. class clusters were defined as three or more ahc cases in one class of students within days. both family clusters and class clusters were charted through epidemiological investigation. . tempo-spatial data analysis. district-specific ahc attack rates were calculated by dividing the number of reported cases for each district by the total number of schoolchildren under its supervision. the kriging method [ , ] , a statistical mapping technique utilizing data collected at each location, was used to interpolate each grid cell over a spatial domain. in this study, the centroid of each grid designated the attack rate in each district. in order to observe spatio-temporal spreading, kriging assessed the spatio-temporal interactions in a diffusion map. we made a surface plot of daily time series as a gradient interpolated between adjacent days and district data points. distance in the map symbolizes relative geographic relationship rather than actual distance. townships were ordered from east to west and from north to south. to identify the possible etiologic agent of the outbreak, health care professionals were required to administer eye swabs and conduct laboratory testing. local health workers were then able to match the epidemiological characteristics for the confirmed agent, coxsackie a , with appropriate and specific prevention and control measures. government officials of the taipei city department of health informed the media of the outbreak through press releases and used a variety of health education methods to reach the public. beginning on october , public service messages were delivered to kindergartens, primary schools, middle schools, and high schools to encourage children to avoid touching their eyes, wash their hands routinely, and participate in disinfecting the school environment. within schools, health education programming during daily morning assemblies provided updates to students and teachers regarding the current status of the epidemic and additional measures that were needed to reduce infections. a special telephone hotline was also established to improve case reporting and provide up-to-date disease counseling from health care institutions. these measures, though helpful, had also been used in keelung and had, thus far, proven inadequate at containing the epidemic. in early october , taipei city government decided to adopt a more aggressive campaign against the epidemic by implementing an ''incident management system.'' this system required various administrative agencies to follow an integrated disaster response plan. although school closures and class cancellation were not required for schools with reported ahc cases, schools were encouraged to persuade symptomatic students to stay home and provide guidance on how to prevent the spread of the infection in the home environment. in addition, schools were authorized to keep symptomatic students from entering the school in case parents insisted on their attendance. if infected students were able to gain entry to school premises, the school was authorized to prevent them from joining public activities (such as swimming). school absenteeism was also reported and recorded daily. the taipei city department of health devised backup plans should the above-mentioned measures not succeed. these plans included separate care facilities for ahc patients at ophthalmic clinics, more intensive segregation of symptomatic students from classmates (in the classroom, at public washbasins, and during outdoor student activities), and quarantines that required symptomatic students to stay at home for seven days. monday incidence reports ( figure ) exhibited tremendous increases in ahc case incidence during weekends in keelung. mindful of these weekend spikes, taipei implemented a multichannel risk communication prevention program during the weekend of friday, october ( , new cases of ahc were reported in taipei on that date). this risk communication program focused on communicating directly to the public through three routes: ( ) schools delivered a taipei department of health letter signed by the mayor (that detailed ahc information and prevention methods) for students to take home to their parents, ( ) the mayor held a press conference to discuss the epidemic and offer guidance to citizens for preventing the spread of the disease, and ( ) over . million short message services (sms) messages, a communication tool for exchanging short text messages between mobile telephonic devices, were delivered to all taipei mobile phone numbers. the messages briefed taipei residents on the current status of the epidemic and recommended citizen-level control measures. all communications suggested that symptomatic students stay at home, apart from other members of the family, and recommended household disinfection. on october st, all taipei students involved in the study were asked to give their parents a questionnaire devised to collect epidemiological data and assess their opinions regarding taipei city's infection control measures. the questionnaire asked about the clinical symptoms/signs of children with ahc, school attendance, and inquired on parents' sources of disease prevention information. parents were also asked to comment on their degree of satisfaction with taipei city's public health efforts and provide suggestions for improving future sms alerts. we evaluated the effectiveness of the control measures based on the duration of the epidemic and the attack rate of the disease among school students in both taipei and keelung. as keelung was without a risk communications program, and had only applied the general control measures recommended by taiwan's center for disease control (taiwan cdc), the effectiveness of the special measures taken by taipei city could be readily calculated through direct comparison. because this study utilized risk communication methods used to minimize the public health threat of an unusual outbreak, we briefly describe the ahc epidemic below and analyze the effectiveness of the chosen methods using epidemiological measures. . ahc attack rates in taipei and keelung cities. at the beginning of the epidemic, the etiologic agent of this ahc outbreak was unknown. on october th, based on culture and sequencing analysis performed at taiwan cdc, the pathogen was identified as the a variant of the coxsackie virus [ ] . the epidemic lasted days in taipei ( , cases), and days in keelung ( , cases) ( table ) . keelung city applied general control measures and keelung cdc monitored daily reported new cases as suggested by taiwan's cdc. however, there was no further assessment by keelung on the effectiveness of its control measures. the crude attack rate of ahc in keelung was significantly higher than in taipei ( . % vs. . %; p, . ). after the risk communication program was implemented in taipei the overall incidence in the city decreased significantly ( . % before vs. . % after; p, . ) while the incidence rates in keelung continued to increase almost every weekend ( figure ). the greatest number of ahc cases in taipei city occurred on a friday (october ), signaling an upcoming weekend spike in infections. however, on that day, taipei city government launched the multi-channel risk communication program, greatly reducing the incidence rate and, in effect, causing a sharp weekend drop in new cases. because of such measures, the epidemic ebbed much earlier in taipei than in keelung ( figure ). . epidemiological characteristics. the outbreaks began in keelung in september of . due to the high frequency of transportation from keelung to taipei, the epidemic gradually reached taipei. districts in taipei city closest to keelung city began to see an increase in their attack rates on october th (figure ). the wave of new infections moved steadily from the northeast districts to the southwest districts of taipei. in both cities, the disease spread citywide within a short period ( days), as shown in figure , and the median time between exposure and onset of disease was as short as day [mean standard deviation (sd): . . days, range to days] [ figure ]. the mean time from exposure to onset of ahc was significantly shorter in family clusters than in school cluster cases (mean sd: . . vs. . . days, p = . ). the mean and range of time between exposure and disease onset was also significantly shorter in larger family clusters (. ahc cases per family) than in smaller ones (, = = ahc cases) ( . . days, range to days vs. . . days, range to days, respectively) (p, . ). in terms of risk factors (table ) , boys were at significantly higher risk for ahc-related pink eye than girls (or = . , p, . ), and older children (over years old) were generally at higher risk for pink eye both at home (or: . , p = . ) and at school (or . , p, . ). in general, children at northeastern taipei schools, located closest to keelung, were at greater risk for pink eye (or = . , p-value = . ) both at home (or = . , p-value , . ) and at school (or = . , p-value = . ), than those at schools located in districts further away (figure ). in addition, school children were identified as the index cases in . % of fifty-three family clusters ( / ), demonstrating their high risk for transmitting the disease to other family members. . home confinement of symptomatic school children. on friday, october th (a day marked for its dramatic spike in new cases) the multi-channel mass risk communication program was launched in taipei just prior to the weekend. on that day, three containment measures were urgently implemented: ( ) the mayor addressed the press about the outbreak, ( ) a letter written by the taipei city department of health and signed by the mayor was given to students to take home to their parents, and ( ) sms messages were sent to all taipei citizens with mobile phones. the collective message of all three channels emphasized the severity of the outbreak and outlined preventive measures, including home confinement. according to results obtained from the questionnaire (table ) , home confinement of symptomatic students increased from a rate of % prior to the implementation of the risk communication program to % afterwards (p, . ). . disease containment. as mentioned above, taipei launched its mass risk communication program on october th. this was also the day that the epidemic reached its highest peak. as demonstrated in figure , the pre-weekend case surge was reduced by almost half by october th (following the mass risk communication campaign in taipei). in keelung, where no such risk communication program was launched, the epidemic lasted for thirty-four days and had fourteen days of high attack rates within that period. in contrast, the epidemic lasted thirteen days in taipei and had less than five days of high attack rates following the implementation of the risk communication program. the diffusion map in figure further illustrates the limited scope and short duration of high ahc attack rates (labeled in red) in taipei districts. by october , attack rates in all taipei districts reduced to moderate levels (labeled in yellow) and then further reduced to low levels (labeled in green) on october (figure ) . according to taipei city's parents' responses to the questionnaire, primary sources for ahc information included tv news broadcasting ( . %), daily school health education programs during morning assemblies ( . %), and the taipei city department of health letter signed by the mayor ( . %) ( table ). approximately fourteen percent ( . %) of parents surveyed identified the short message service (sms) issued by the taipei city department of health as their primary source of ahc information. based on a five-point scale, parents who received the sms communication felt more satisfied with this method as a means of public health communication than those who did not receive sms messages ( . vs. . ; p, . ). prompt and effective prevention and control measures to combat eids are imperative to maintaining public health and safety. in this study, we found that the multi-channel risk communication program launched midway through the ahc epidemic in taipei city increased the number of students confined to their homes, reduced total duration and affected areas of the epidemic, and decreased the number of dangerous, high attack days. by interrupting the prevailing transmission route between school and home, the program effectively inhibited the spread of this highly communicable disease in the community. ahc has been identified as a highly contagious disease, capable of far-reaching, epidemic spread, since its first reported case in [ , ] the coxsackie virus a (cv-a ) variant in particular has been the causing agent of several difficult outbreaks. it has also been a significant challenge to sensitivity and timeliness efforts in disease surveillance systems [ , ] . in addition, the virus's eye-related symptoms [ , , ] are not easily differentiated from other infections (i.e. the human strain of netherland's avian influenza, h n ) [ , , , ] . during the ahc epidemic in taiwan, schools were found to be epicenters of transmission. by focusing disease control efforts in the school system, taipei was more effective than neighboring keelung (which relied on traditional control strategies) at interrupting the school-family-community cascade of transmission. because ahc was not initially listed as a reportable disease when this outbreak first occurred, accessible data was initially unavailable for cases before october , . several characteristics of the outbreak suggest a foreign source for taiwan's ahc epidemic. the introduction of the outbreak in keelung, a port city, and the genotype ii status of the cv- virus (all cv- viruses isolated in taiwanese outbreaks prior to had belonged to genotype iii [ ] ) strongly suggest that the virus was imported in the summer of . the spread worsened in taiwan after schools returned to session in september. although health officials in keelung had advocated for hand washing, eye protection, and disinfection, new cases continued to rise after october . the cv- virus, spread primarily through person-toperson contact and contact with infected fomites, may also have spread through contact with respiratory droplets and fecal-oral routes, resulting in rapid and widespread transmission [ , ] . older children were more likely to be members of case clusters at home and at school. the reasons for this increased likelihood is unknown, though it may be related to higher rates of participation in team sports and/or less compliance with rules of hygiene. research may be needed to fully understand this phenomenon. in essence, school children serve as index cases in around seventy-five percent of family clusters (table ) and are, indisputably, the largest transmitters of the virus. the findings of the study illustrate that schools serve as epicenters of cv- transmission and are effective intervention targets for containing the virus before its introduction to the general population. the large weekend increases of cv- infection that occurred in keelung may have resulted from a lack of preventive measures at home, e.g. ineffectiveness at keeping symptomatic children separate from other family members and/or improper disinfection of the home environment. because the median time from exposure to onset is short (median day in figure ), ahc is able to spread quickly from one index case to other family members, many of whom might take it back to schools and larger communities over the weekend. this creates a highly efficient family-schoolcommunity transmission cascade that is capable of spreading quickly throughout a city. therefore, measures that effectively reduce and isolate infections at home and at school would contribute greatly to breaking the transmission cycle. in the face of an unexpected outbreak of eid, risk communication and management are essential for keeping infection and mortality rates under control. the large disparity between mortality rates of the influenza pandemic in philadelphia and st. louis in the united states was due to distinct differences in the preparedness and timeliness of their respective local public health responses [ , ] . this example serves to illustrate the importance of preventing and containing eids in a systematic and timely manner. as the capital of taiwan, taipei city has a much larger population size and density than keelung city (table ). in addition, taipei is a highly dynamic city with frequent economic, cultural, and social change. this inconstancy, coupled with its status as a large international travel hub, makes the city particularly vulnerable to eid. much of taipei's preparedness was the result of the city's experience as taiwan's epicenter of the sars outbreak in . after the sars outbreak, taipei city government initiated a new public health plan using an integrated infection control system against eid. this new system integrated early detection of outbreaks (particularly in hospitals and schools), epidemiological investigation, and epidemiologically based public health prevention and control policies. the renovated division of disease control and prevention (taipei's cdc) also became the core operational unit for implementing crisis management procedures and facilitating policy. these systematic upgrades allowed for quick enactment of multi-channel risk communication measures during the outbreak of conjunctivitis. the ahc outbreak provided the perfect opportunity for taipei health authorities to test the effectiveness of the newly renovated system. measures that were used to contain this epidemic may also, in turn, serve as a practice model for dealing with future influenza pandemics. there are many similarities between ahc and novel influenza: ( ) there is currently no available vaccine for the circulating virus strain and anti-viral treatment is limited, ( ) time from exposure to onset is very short, ( ) the disease is highly contagious and easily contracted through contact with contaminated aerosols/droplets or fomites, and ( ) schools serve as epicenters for the spread of the virus to households and, eventually, to the larger community. it has been previously demonstrated that home confinement of symptomatic children can dramatically limit the spread of ahc and influenza in the community [ , , ] . the timely launch of our multi-channel risk communication program to all taipei citizens on friday, october , allowed us to provide clear instructions to families on how to prevent the infection at home over the course of weekend, when infection rates would normally increase. these direct communication methods successfully convinced parents to keep their symptomatic children at home (from % to % in table ). with contagious students confined to their homes, school transmissions decreased dramatically and public health officials were able to contain the taipei outbreak quickly. the effectiveness of these innovative methods in the heavily populated metropolitan area of taipei city was evidenced by how quickly the epidemic, which had infected students, subsided after weeks. this can be compared with the two months that were needed to control taipei's previous cv- epidemic in [ ] . the importance of appropriate risk communication in response to disasters has often been overlooked by public health officials in taiwan. traditionally, the mass media has helped disseminate epidemic information and increase awareness on how health risks may be reduced. however, the modern mass media has, at times, had a negative impact on public health efforts by encouraging public indifference or sensationalizing incomplete and inaccurate information. the media's reporting of the sars outbreak contributed to unnecessary chaos in the early phases of the epidemic [ ] . rather than rely on the media alone to convey productive messages regarding the epidemic, taipei's cdc was able to implement its multi-channel mass risk communication program to reach the public directly during critical points in the epidemic. we believe the sms messaging component of the program was integral to the success of the ahc intervention and will continue to explore the use of this tool. we know from our questionnaire that fourteen percent of parents who confined their affected children at home during 's ahc outbreak reported that their decision to comply with this preventive measure was based on the sms messages they received. although the effects of the cell phone method cannot be fully isolated from the multichannel risk communication system in this study, we believe that future interventions that utilize sms exclusively will provide more insight on the effectiveness of this method. taipei's cdc has since conducted a sms campaign on chinese valentine's day in to reach high-risk groups for human immunodeficiency virus (hiv). the message asked the public to answer an aids-related trivia question and also provided information on free, anonymous hiv testing. after this exploratory campaign, anonymous hiv screening rates went up % from the same time the year before. as sms messaging is still an emerging approach to wide-scale information dissemination, we believe that further examination into the effectiveness of cell phone-based risk communication methods will need to be done at the local, national, and international level. taipei's ability to launch such a large-scale sms campaign was a direct result of taiwan's communicable disease act ( ). this act allowed government officials to override the people's right to privacy when responding to epidemic disasters. in this case, the taipei city government held a contract with taiwan's six major mobile phone companies and committed all of them to allowing six free public service messages (per year) to be sent to their users if deemed necessary by the proper authorities. the sms message in response to the ahc epidemic was sent to . million registered mobile phone users in taipei city. public satisfaction with the sms campaign was high, especially amongst parents of school children. while this mass communication method has been advocated for use in many asian countries, taiwan's large-scale employment of sms technology was, to the best of our knowledge, the first such attempt in the world. while it was, overall, an effective means of communication, the efficacy of this method was limited by several factors. first, the sudden influx of over two million messages put a large burden on the network system and resulted in a long delay (many received their message around midnight). second, many taipei mobile phones users are registered in other cities and did not receive the messages. third, consumer weariness may have caused some people to ignore the long, unsolicited message before they read it. to reduce technical limitations, we suggest that sms surge capacity be increased and tested at both non-epidemic and pre-pandemic stages. other limitations to the sms tool and alternative mass communication prevention methods can be fine-tuned with more experience, frequently updated guidelines, an efficient system for risk management, an integrated public health plan, and extra training for public health personnel [ , ] . another important challenge is reaching diverse populations, particularly those with low socio-economic status that may not be able to afford mobile phone service (and reside in less affluent, high-risk areas) [ ] . this may be less of problem in taiwan than in other countries. this study had several limitations, including a lack of early data on pink-eye cases in keelung. after the conclusion of the outbreak, there was also no further assessment on the effectiveness of control measures in keelung. this study was non-randomized and missing epidemiological information for calculating secondary attack rates, age-specific asymptomatic ratios, and geographical diffusion of ahc cases outside taipei and keelung. seroepidemiological studies in the future should be able to obtain more accurate secondary attack data with the use of comprehensive infection and disease exposure data. in conclusion, the timely launch of the multi-channel risk communication program described in this study greatly reduced the duration and number of cases of taiwan's ahc epidemic. these efforts effectively avoided a potentially large-scale epidemic of ahc in taipei city. in encountering challenges such as outbreaks of influenza pandemic, or other eids with short incubation periods, public health officials need to prepare an integrated and timely administrative public health response. urgent intervention and education must reach the community directly through multi-module channels, like sms, for rapid communication. geographical variations in epidemiological characteristics, as described in our comparison analysis of the ahc epidemic in keelung versus taipei, are similar to variations in swine-origin h n outbreaks in mexico versus united states. such similarities support this intervention's potential applicability to the prevention and control of other eids. based on the findings of this study, we believe that the success of this risk communication method is dependent on: ( ) the timeliness of the communication, ( ) simplicity and consistency of the message, ( ) appropriateness of the channels of dissemination, ( ) transparency of the information, and ( ) public faith in the communicator; in this instance the mayor of taipei. while we found that the use of sms significantly contributed to the effectiveness of the risk communication program, more sms-based campaigns and research, like the hiv testing campaign mentioned in our manuscript, are needed to fully evaluate its effectiveness at communicating public health messages to the public. file s informed consent and questionnaire. written informed consent was obtained before parents of the participated schoolchildren responded to the questionnaire. found at: doi: . /journal.pone. .s ( . mb pdf) unusual type of epidemic conjunctivitis in ghana enterovirus type : the etiologic agent of pandemic acute haemorrhagic conjunctivitis an epidemic of acute hemorrhagic conjunctivitis due to coxsackievirus a epidemic acute haemorrhagic conjunctivitis due to coxsackie virus a variant in ghana a recent epidemic of acute hemorrhagic conjunctivitis an outbreak of acute haemorrhagic conjunctivitis in melaka, malaysia acute hemorrhagic conjunctivitis epidemic caused by coxsackievirus a variants in korea during 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of health information in the news media infectious diseases and governance of global risks through public communication and participation ethical decision making in a crisis: a case study of ethics in public health emergencies infectious diseases and governance of global risks through public communication and participation we greatly appreciate local public health professionals who helped coordinate and implement efforts for controlling the ahc outbreak. we are also grateful to the taiwan cdc for their laboratory support. the authors would also like to thank two english editors, mr. james steed and ms. peggy lee, for their assistance in the final edits of this manuscript. conducted geographical diffusion data analysis using a geographical information system: tcc. responsible for designing the epidemiological study: cck. formulated questionnaire questions: cck. selecting focus areas for data analysis: cck. revised this manuscript: cck. key: cord- -n ek fw authors: shah, pooja; patel, chetan r. title: prevention is better than cure: an application of big data and geospatial technology in mitigating pandemic date: - - journal: trans indian natl doi: . /s - - -y sha: doc_id: cord_uid: n ek fw covid- has been a severe threat to city’s dense ecosystem and has collapsed the urban life. these spread has raised question on urban health infrastructure and coping capacity. to maintain social distance and providing community with essentials is a challenging task for government and city planners in dense urban area. spatial mapping of resources, patients, medical infrastructure, potential open space, places which can be turned to quarantine centers, etc. has been done using gis for city of surat. larger open spaces within the urban fabric are identified to implement emergency services and evacuation protocols. this tool will defiantly be helpful to the city administration in maintaining the cluster, quarantine tracking of the infected community and flow of daily essential, supply chain in cities with restriction in the infected cluster. even having better technology to fight against any pandemic, geospatial technology will help to prevent the pandemic to spread further and hence, it is known as prevention is better then cure. recently, geospatial technique has been used as boom word in the field of technology and science. when the world is facing such a treacherous global outbreak covid- , the question that arises in the mind of researchers is that how can we use out technologies as boon. the pandemic of the novel coronavirus disease has caused more than , , people infected and around one lakh of deaths (coronavirus disease ). currently, the number of infections and deaths is still increasing rapidly. covid- seriously threatens human health, production, life, social functioning and international relations. geographic understanding is essential in detecting, understanding and responding to any infectious disease outbreak specifically in pandemics such as coronavirus disease . even with the well-known technology, the pandemic can be cured but can be better way prevented by geospatial technology; hence, it is known as the technology for prevention of spread of pandemic. this paper will demonstrate how this technology will be helpful in mapping, prediction and understanding behavior of cluster under quarantine. for the understanding of technology, surat is considered as the case. this tool will defiantly be helpful to the city administration in maintaining the cluster, quarantine tracking of the infected community and flow of daily essential, supply chain in cities with restriction in the infected cluster including mongering of the same. in the battle against covid- , geographic information systems (gis) and huge information innovations have assumed a significant job in numerous angles. gis encourages disease transmission experts to delineate event against various parameters including socioeconomics, the earth, geologies and past events to comprehend the starting point of episodes, its spread example and its power to execute control, preventive, and reconnaissance measures. general wellbeing organizations, arrangement creators and executives need gis to comprehend flare-up designs progressively to recognize in danger populaces and plan focused on mediation, for example, assess accessible offices or increment social insurance limits. likewise, there is a requirement for compelling correspondence among other supporting organizations and residents to guarantee a planned reaction. kamel boulos and geraghty ( ) focus and portray a scope of functional on the web/versatile gis and mapping dashboards and applications for following the / coronavirus pandemic and related situations as they develop far and wide. a portion of these dashboards and applications are getting information refreshes in close ongoing (at the hour of composing), and one of them is intended for singular clients (in china) to check if the application client has had any nearby contact with an individual affirmed or suspected to have been contaminated with sars-cov- in the ongoing past. they have likewise referenced extra ways gis can bolster the battle against irresistible sickness flareups and pestilences. during the covid- flare-up, mapdriven dashboards, for example, the ones by johns hopkins csse, the who and early alert inc., have turned into a web sensation themselves, advising both the general population and wellbeing experts. yet, dashboards are only the start of how gis and area advancements can bolster the battle against irresistible diseases. arab-mazar et al. ( ) have exhibited instances of covid- in iran and how the specialists have brought choices to close down nearby ventures and support social separating. time-empowered maps can uncover how diseases spread after some time and where you might need to target mediations. covid- disproportionally impacts certain socioeconomics, for example, the old and those with fundamental wellbeing conditions. mapping social helplessness, age, and different elements assist you with observing in danger gatherings and areas you serve. guide offices, workers or residents, clinical assets, hardware, products, and administrations to comprehend and react to present and potential effects of covid- . utilize intuitive web maps, dashboard applications, and story maps to help quickly impart your circumstance (coronavirus: how enterprises are using gis to track covid- impact, it news, et cio, n.d.). gis has created and developed moderately rapidly and has a total innovative course for information planning, stage development, model development, and guide creation. be that as it may, for the battle against the across the board pandemic, the fundamental test is discovering techniques to change customary specialized strategies and improve speed and exactness of data arrangement for social administration. at the information level, in the period of enormous information, information no longer come fundamentally from the legislature yet are accumulated from progressively various ventures. therefore, the utilization of gis faces troubles in information securing and the combination of heterogeneous information, which requires governments, organizations, and scholarly establishments to together advance the plan of pertinent approaches. at the specialized level, spatial investigation strategies for large information are in the command. at present and for quite a while later on, the advancement of gis ought to be fortified to frame an information driven framework for fast information procurement, which implies that gis ought to be utilized to strengthen the social activity parameterization of models and techniques, particularly when offering help for social administration (zhou et al. ). the effects of the worldwide covid- pandemic are still being understood; however, it seems clear that this emergency will make a blemish on urban areas, truly and socially, that will resound for ages. the covid- pandemic has as of now fundamentally changed urban life. the number of individuals moving around has dropped to uncommonly low levels. the destiny of a large number of private ventures and laborers that make urban focuses work is not yet decided (van den berg ). while the city planners are still struggling to maintain balance between logistic planning and resource management, dense urban built up, affordable housing and other factors are challenging the planners to find out potential site for covid- patients and quarantine. there are various dashboards around the globe for monitoring and anticipation of covid- spread. legger ( ) demonstrated data smart solutions practiced by various government across the world to effectively fight covid- . the article emphasis on how mapping resources and assets provide potential solution to the community. indian government has also launched aarogya setu app to get information regarding individual's vulnerability to covid- . this app records details like location, demographic details, travel history and contact with covid- positive patient. this app can be downloaded by the smartphone users in india. the app is boon for the citizens of india, but the challenge still remains for decision makers as, out of total of crores population of india, it has been downloaded only in . crores smartphones (aarogya setu app downloaded in . crore smartphones-the new indian express, n.d.). decision makers require integration of the demographic data, spatial data of individuals, locations of essential resources, road network density, population density, etc. to identify shortest route, nearby facilities and potential quarantine centers. such datasets can be analyzed on any open source or commercial geospatial software. looking into the global pandemic, fema and esri are providing free access to data mapping technology in response to covid- till august . the predicting strength of the software is explored by developing model to predict the cases of covid- using explanatory variables like population density, building density, building heights and types of use of land like housing, commercial or industrial and positive cases of covid based on above parameters the prediction model will help to show the probable area of containment using this model, the severity of the pandemic can be tracked and can be monitored to avoid further spread of diseases. in the present research framework, surat city of gujarat has been considered as study area. surat is a city located on the western part of india in the state of gujarat. it is one of the most dynamic city of india with one of the fastest growth rate due to immigration from various part of gujarat and other states of india (smc ). surat is mainly known for its textile and diamond market. the people engaged in these industries are majorly daily wage workers. coping with capacity to suffice the needs of all migrants, labors along with maintaining social distance and providing accommodation has to be the need of the hour. application of gis has been used for spatially mapping patients, hospitals, open spaces in case of emergency. the first stage is designing of research statement "integration of spatial database for policy planning of potential mapping, essential services to prevent spread of covid- ". vis-à-vis literature state of art was carried out to understand the global geospatial methods adopted by policy makers and administration in response to covid- . research gaps were found keeping in mind the limitation due to covid- . formulation of research question such as what is land suitability, why it is required and what are the parameter or criteria that affect the land suitability were taken up to make resilient policies against covid- . land-use map of surat city is prepared to identify available land. this is done by taking satellite image and analyzing in arcmap. next step is to identify parameters that affect the land suitability and preparation of factor maps. this criteria or factor maps are converted in to raster map so that it can be classified into number of classes. the next step is to give the suitable score to each class of factors. this score ranged from low suitability to high suitability; the higher the score, the more suitable the land is. the next step is to give the weight to each criteria map. to prepare land severity map, a spatial tool known as weighted sum is used which gives the final severity score to each pixel. then, the score is divided into various part with high score indicating highest severity and low score indicating less severity. based on the suitability score map is divided into various classes. flow chart for methodology adopted in this study is shown in fig. . area severity analysis for present study is carried out through weighted sum overlay technique in gis. factor map of various parameters have to be overlaid. for preparing factor map nearest distance is calculated through euclidean distance tool of spatial analyst in arcgis to check the influence of each parameter. then, the nearest distance tiff file is reclassified into five classes and score is given on one-five rank. for population density, land cover, elevation and slope map, euclidean distance is not required. in socio-economic criteria, less population density, less travel time to commercial area, minimum distance to education facilities from residential area and maximum potential of growth node, for utilities, minimum distance from major roads, minor roads, railway lines, airport and major transportation center, in environment, area which is nearby stream and water treatment plant and far from sewage treatment plant and landfill site and as a physical criteria, open land, agriculture land and sparse vegetation, less slope and more objective literature review fig. methodology adopted for study elevation are considered as more influential parameters for urban pandemic spread. factor maps of all sub-parameters are as shown in fig. . all the factor maps are taken as input and their weight are entered in weighted sum tool of arcgis, and resultant raster map is classified into the five classes, that is, very suitability, suitable, moderately suitable, less suitable and unsuitable as shown in fig. . real-time mapping of patients, essentials to be supplied, demarking the red zone, orange zone and green zone as per the covid- patients in an area is effectively done on gis. spatial interpretation of such data can be very useful for any kind of disaster management in urban planning. suitable area indicates wards with low risk, unsuitable indicates wards with high risk. considering all the essentials, travel time to maintain supply chain, the suitability maps provides with potential location. figure shows spatial distribution of patients tested positive for covid- , along with those discharged and deceased. as per the densities of patients in a ward, the wards are indicated as red, green, and orange ward. density of positive tested patient is more on the western part of city. rander ward of city has maximum number of patients. it is denoted as high vulnerable area in red. such wards should be completely sealed and no movements should be allowed. fig. a population density, b distance to commercial, c distance to major road, d distance to major transportation center the use of geospatial technology can be a major asset for policy makers and urban planners to identify and demarcate the areas with the pandemic effect. the datasets from apps like aarogya setu, municipalities dashboard can be integrated with the spatial resources of cities for extraction information effectively. esri along with fema are providing free access to data and mapping technology in response to covid- . the big data on land-use pattern, population density, major clusters with high and low risk, supply chain points or cluster, transportation nodes for daily essentials supply are very much helpful in managing the impact of the pandemic. the use of such data in surat city has helped in managing the spread of the covid- effect. based on the database gathered by the city administration, it was used for mapping clusters which helped in tracking the possible zone with covid- pandemic. if this kind of technology will be used by all municipal corporations in india, then this may help to control the spread. further, it may help in managing the lockdown and making the supply chain effective by maintaining the social distance too. these types of geospatial technology can be used as spatial tool for resource allocation, health center location and land suitability as demonstrated for the above city. major challenge to the decision maker is the absence of systematic big data and resources for the geospatial technology. interactive dashboards like that of smc should also be developed by other cities. very few indian municipalities have shown the data visualization on their websites. cities like mumbai, ahmedabad, pune, delhi, etc. which are highly vulnerable to covid- should map covid- related information for better visualization. from now, if the government will focus on spatial infrastructure development along with the physical and social infrastructure development, then in near future, it can be a blessing to the decision makers and they can prevent spreading of pandemic in the nation to have, "prevention is better then cure".. aarogya setu app downloaded in . crore smartphones-the new indian express. (n.d.). retrieved coronavirus: how enterprises are using gis to track covid- impact, it news, et cio geographical tracking and mapping of coronavirus disease covid- /severe acute respiratory syndrome coronavirus (sars-cov- ) epidemic and associated events around the world: how st century gis technologies are supporting the global fight against outbreaks and epidemics covid- response: gis best practices in local government|data-smart city solutions munic ipal.gov.in/theci ty/ intro ducti on van den berg r ( ) how will covid- affect urban planning? thecityfix covid- : challenges to gis with big data key: cord- -x ykd authors: van der hoeven, arno; hitters, erik title: the spatial value of live music: performing, (re)developing and narrating urban spaces date: - - journal: geoforum doi: . /j.geoforum. . . sha: doc_id: cord_uid: x ykd this paper examines the spatial value of live popular music by adopting an inter-disciplinary approach grounded in urban and music studies. what is understood of the relationship between live music and the built environment is improved, with a focus on how this cultural form contributes to performing, (re)developing and narrating urban spaces. the post-industrial city has become a stage for events that serve a wide range of social, cultural, economic and spatial objectives. however, the densification of the built environment has led to a debate about the extent to which live music’s positive outcomes outweigh the nuisance experienced by residents in terms of noise and the unavailability of public spaces. furthermore, small venues in many cities are struggling with issues of gentrification, implying that the spatial value of music is part of wider concerns about who owns the city and which forms of culture can be produced and consumed in urban centres. against this background, the paper asks the following questions concerning the spatial value of live music: how can it be defined? what are the challenges to achieving it? how can it be supported in urban planning? the study is grounded in a qualitative content analysis of live music reports and strategies, as well as in-depth interviews with policymakers, festival organisers and venue owners. also discussed is how the spatial value of live music can be supported in urban policies by building interdisciplinary networks, establishing strategies, and creating and sustaining places for live music events. this article examines the spatial value of live popular music, with a focus on how this cultural form contributes to performing, (re)developing and narrating urban spaces. music events occur in diverse places, which vary in terms of their size, organisation and level of professionalism, and include bars and community centres, as well as big festivals and arenas. as we will argue in this paper, live music concerts should not be dismissed as just temporary forms of entertainment: they can have a long-term impact on the built environment and the way in which people experience the urban landscape (wynn, ; nunes, ; richards, ) . in recent years, the role of the cultural form of live music has been more prominent in both the music industries and urban policy. indeed, as the revenues from recorded music declined, that performed live became central to the former's business models (mazierska et al., ) . roberts ( , p. ) . this reminds us that recorded and live music have different geographies, with the latter literally requiring more space in cities: " [it] is in urban areas that the live music industry has carved out its augmented geography over the past decade." new venues, like flagship music arenas, are testament to live music's value in urban development (kronenburg, ) . indeed, the post-industrial city has become a stage for a growing number of events that serve a wide range of goals, including urban branding and increasing cultural vibrancy (jakob, ; van der hoeven & hitters, ; wynn, ) . nevertheless, live music's embeddedness in cities poses multiple spatial challenges: the densification of the built environment has led to a debate about the extent to which live music's positive outcomes outweigh the nuisance caused to residents in terms of noise and, for instance, the accessibility, or even unavailability, of public parks; the privatisation of urban spaces, which constrains the opportunities for live music events to be held in some cities (cohen, ; kronenburg, ) ; and many musicians and small music venues are struggling to cope with increasing rents (shaw, ) . this all suggests that the spatial value of music is part of a wider concern about who owns the city and which forms of culture can be produced and consumed in urban centres (roberts, ; sassen, ) . against this background, this paper answers the following questions in relation to the spatial value of live music: how can it be defined? what are the challenges to achieving it? how can it be supported in urban planning? the project contributes to the development of the concept of live music's spatial value and examines how this can be achieved. it also adds to the field of urban studies by exploring the relationship between live music and the urban space. in doing so, we build on previous research on live music's materiality, geography and architecture (e.g., wood et al., ; kronenburg, ) . this enables readers to understand how the connections between musical performances and urban space develop and can be supported. while earlier studies have paid attention to the social, cultural and economic value of live music to cites (behr et al., a; van der hoeven & hitters, ) , this project takes a different approach by examining the impact on the built environment in its own right. our scope is limited to popular styles of live music in cities in order to improve the focus of the study. we do, however, acknowledge that other forms of music have a spatial impact and their performance is not exclusive to cities. our article demonstrates that the concept of spatial value is contested and complex, being shaped by a wide range of different actors with conflicting interests. moreover, the spatial value of live music needs to be understood in relation to wider political and economic forces that affect how and where it is performed and with what effects. these findings are grounded in interviews with event organisers, directors of music venues and real estate experts in the netherlands. we have also analysed live music reports and strategies from eight different countries. the next section discusses the existing literature on the relationship between music and urban space, enabling us to conceptualise spatial value. there is then a description of the research project and its methodology, followed by a discussion of the challenges to achieving spatial value. this distinguishes between the impact of and on the urban environment in which live music is embedded. finally, we address how spatial value can be supported in urban planning and policymaking. here, we discuss three vital steps for strengthening urban live music ecologies: ) building inter-disciplinary networks; ) establishing urban strategies; and ) creating and sustaining places for live music. this section provides a conceptualisation of spatial value that is grounded in the existing literature on the relationship between music and the built environment. the concept of 'value' is used to achieve an understanding of the various benefits of urban live music ecologies, which can be understood as the networks of venues, festivals and social actors that support live music performances (behr et al., a; van der hoeven & hitters, ) . the importance of the intrinsic value of live music as an end in itself should be understood before turning to the values of live music ecologies. this intrinsic value is a necessary condition for realising any of music's more instrumental effects (behr et al., b) . in other words, our discussion of the uses of live music in cities is not intended to deny the rich personal, communal and aesthetic experiences involved in the enjoyment of this cultural form. the spatial value of live music is understood as an addition to three other values that have been defined in earlier research (van der hoeven & hitters, ): ) social value refers to live music's contribution to social relationships (i.e., social capital), the public engagement of live music organisations (e.g., charity, volunteering and activities for the neighbourhood) and a sense of identity; ) cultural value is connected to musical creativity, talent development and cultural vibrancy in cities; and ) economic value concerns financial benefits and the relevance of live music for cities in monetary terms (e.g., increased tourism and job growth). conceptualising spatial value is necessary if there is to be a more comprehensive understanding of how live music shapes, and is shaped by, urban spaces. as we will argue in this literature review, live music's spatial value concerns the relationship between live music and the built environment, as constituted by the dimensions of performing, (re)developing and narrating the urban space (see table ). according to adhitya ( ) , the city is a stage for urban performances. the architecture and urban design shape the rhythms of our movements, just like music. urban planners, adhitya explains, compose how we go about our everyday lives in urban spaces. the literature in this section of our article supports the argument that music has an impact on how cities are used and performed (connell & gibson, ) . indeed, the musical activities taking place in dedicated venues or the urban environment, with street music (bennett & rogers, ; bywater, ) and festivals being examples (kronenburg, ) , shape how we experience urban space. arguably, one of the most significant places in people's experiences of music are the stages where performers and audiences meet. here, we can make a distinction between festivals as temporary stages and permanent bricks and mortar venues. in relation to the former, wynn ( ) observes a trend of festivalisation, in which an increasing number of temporary events are organised to achieve different spatial, socio-cultural, symbolic (e.g., urban branding) and economic objectives. festivals often provide a spatio-temporal platform for alternative lifestyles (friesen et al., ; kearns, ) , addressing issues of inclusivity (e.g., all-age festivals and openness to cultural diversity) and sustainability (e.g., waste reduction). wynn identifies three different spatial patterns for festivals, with varying levels of spatial control and consolidation. these include the citadel pattern in a bounded space with a single event, the more open core pattern, in which activities take place in and around a particular area, and the confetti pattern, where events are spread about a city in diverse locations. fenced-off festivals in particular, which each have their own stage lay-outs and facilities, can be experienced as a different world (kearns, ) . in contrast, those without fences have a stronger connection to their urban surroundings. in terms of venues, kronenburg ( kronenburg ( , makes a useful distinction between adopted, adapted and dedicated buildings for musical performances. adopted venues are places that are not intended to be used for music events, but can be if only a few changes are made to an existing building. in the case of adapted venues, the original building is modified significantly, while dedicated venues are, in contrast, specifically designed and built as places for musical performances. it is clear that the physical locations where music is performed greatly affect the relationship between live music and the built environment. in a study of the connections between performance and the geography of music, wood et al. ( : ) argue that musical activities have a strong material dimension: "music making is a material practice: it is embodied and technologised; it is staged; it takes place." different event and building types each have their drawbacks and benefits; for example, the main problem with using existing buildings for live music is that they are not normally designed to optimise acoustics and service the needs of audiences. an advantage, however, is that they do not have to take the usually larger economic risks associated with dedicated music venues, which require significant investment (kronenburg, ) . furthermore, adapted buildings like factories actually often add to the atmosphere of a concert through their character and historical associations (bottà, ; kronenburg, ) . indeed, the venue's materiality in terms of smell, size, temperature and building materials shapes the live music experience (behr et al., a) . notwithstanding the specificities of individual venues, it is the diversity of music stages that ultimately matters for a city's live music ecology (webster & behr, ) . as mercado-celis ( ) reminds us, the different stages form a spatially-dispersed network of both public and private actors. rather than focusing on individual stages, his focus is on the mobilities between them. indeed, the career of a musician can be understood as a spatial trajectory through the city, progressively moving from small and informal types of musical activity to more formal organisations (cohen, ) . finnegan's ( ) concept of musical pathways enables an understanding of how music becomes part of the urban landscape. in her work, finnegan focuses on amateur musicians, whose pathways consist of musical landmarks like places where they have rehearsed and performed (e.g., studios and music venues). these pathways are often invisible to others, but nevertheless have great meaning to specific groups or people: "such pathways form one important -if often unstated -framework for people's participation in urban life, something overlapping with, but more permanent and structured than, the personal networks in which individuals also participate. they form broad routes set out, as it were, across and through the city." (finnegan, : ) although finnegan developed the concept of musical pathways by studying amateur musicians, it is also relevant for understanding how other groups make sense of their urban experience through music (espinosa, ) . as an example, music is vital for migrants negotiating a collective identity in a new urban environment, which they do through performances and the creation of social spaces (sánchez-fuarros, ) . a study of the pasifika festival in auckland demonstrates its role in the identity-building of migrants from the pacific islands, promoting wellbeing and celebrating the contributions of pacific peoples to the socio-cultural life of the city in which they now reside (friesen et al., ) . musical pathways are not static (cohen, ) : they evolve through changes in music scenes, artistic developments and new sounds brought about by migration. in that sense, places are relational, since they develop through connections to other localities (andrews et al., ) . similarly, festivals bring a wide range of global influences and styles together in a bounded space (kearns, ) . in raising awareness of the evolving musical histories of cities, cohen ( : ) argues that urban spaces are marked by the physical and affective traces of the musical past, which turn the material environment into a "palimpsest space that offers chronological layers of musical significance, one superimposed upon another, with new layers coexisting with, rather than effacing, the earlier ones." cities are thus a rich setting for personal and collective memories associated with music-making and consumption. urban trajectories become meaningful through, for example, songs about specific streets, knowledge of the location of album cover photos, and memorable concerts (bottà, ; brunow, ; espinosa, ) . similarly, the diverse urban spaces used for music performances are rich in meanings for audiences and participants in music scenes. over the years, they are imbued with particular ideologies and memories, offering a sense of place to specific communities (wood et al., ; andrews et al., ) . alternative do-it-yourself scenes have always been drawn to undesirable and disbanded places like vacant factories, squats or the tunnels used for raves (connell & gibson, ; kronenburg, ) . underground music scenes, which set themselves apart from society's 'mainstream', often find their way to a city's hidden spaces, where they can avoid the control and surveillance taking place in the public realm (brunner, ) . as bottà ( , p. ) argues about the use of urban space by the punk sub-culture: "punk scenes in industrial cities were able to rearticulate the private vacant industrial spaces, into public ones, both materially (by gathering in them) and at the imaginary level (by using them in pictures, lyrics and sounds). however, they also occupied public spaces and made them 'private', winning them as sub-cultural territories." while many venues have their roots in sub-cultural movements and youth culture, the relatively recent phenomenon of new dedicated buildings for live popular music marks a shift in its ideological underpinnings (kronenburg, ) . large arenas not only provide an improved experience for both audiences and artists; they also serve wider goals associated with their flagship status, such as attracting tourists and city branding (holt & wergin, ) . in this case, music venues have developed from counter-cultural spaces to highly professional organisations that are used as valuable instruments by urban planning authorities to promote their city. this role of music in urban development is discussed further in the next section. the effects of live music performances reverberate beyond the venues and festivals where they take place, leaving an impact on their urban surroundings. places where music is performed attract social and cultural activity in their vicinity, thus becoming social hubs for groups of people or central nodes in particular creative networks (cohen, ; florida & jackson, ) . music events are often used in placemaking efforts to improve the quality of a location (richards, ; wynn, ) . according to kronenburg ( : ) , live popular music concerts can be a catalyst for change by transforming the familiar: "the location takes on a different character -it becomes, temporarily, a different sort of space, a place that is activated by the shared experience of an audience engaging together with a performer. rather than a place of transition (to move through from one place to another), it becomes a place to linger (to wait and watch)." in post-industrial cities grappling with urban decay and a loss of social cohesion, cultural experiences, festivals and mega-events therefore became one of the tools used by urban planners to regenerate a location (hitters, ; jakob, ) . many post-industrial cities redefined themselves as centres of experience, consumption, creativity and cultural activity in order to attract a population of middle-class professionals with sufficient spending power (brown et al., ; cohen, ; holt & wergin, ; jakob, ) . in this context of competition between cities, the staging of experiences has resulted in an 'eventification' of place. it has also had the effect that experience-based planning schemes not only include as vital assets investments in hard infrastructure, but also a full and diverse events calendar (jakob, ; marlet, ) . indeed, popular music events can enhance the (inter)national reputation of a city (kearns, ) and provide economic advantages, particularly when table three dimensions of live music's spatial value. the dimensions of spatial value performing urban spaces (re)developing urban spaces narrating urban spaces the physical uses of space to stage concerts (connell & gibson, ; kronenburg, ) and create musical pathways (finnegan, ) . the role of live music in making and regenerating space (cohen, ; roberts, ; richards, ; wynn, ) . live music as part of the stories told about cities. communities claiming spaces, music in the public space (e.g., street music) and identification with music spaces. place-making activities, partnerships between live music organisations and organisations focused on urban development. urban branding, media attention, popular music heritage (bottà, ; lashua, cohen & schofield, ; van der hoeven, ). geoforum xxx (xxxx) xxx-xxx one of its concert locations is included in the world tours of high-profile artists (baker, ; short et al., ) . urban regeneration has thus provided an important rationale for investing in a thriving live music ecology, as it supports urban branding, tourism and gentrification (bottà, ) . venues in landmark buildings designed by 'starchitects' further bolster these economic goals (van schaik, ) . along with this physical music infrastructure, festivals are increasingly used as temporary events to stimulate sociocultural, economic and spatial objectives (nunes, ; van der hoeven & hitters, ) . venues and festivals are therefore often located strategically in derelict neighbourhoods, with the aim being to make them more attractive to future investors and developers. in doing so, live music puts places on the mental maps of potential residents, tourists and property investors. although this implies that live music is now a solid aspect of urban policies, various researchers have actually raised awareness of the negative consequences of using music in places under development. wynn and yetis-bayraktar ( : ) state that the "the marriage of music culture and urban placemaking" results in a commercialization of urban life, for example in the case of the corporate branding of music festivals. consequently, places allegedly become so polished and sterile that this is hard to reconcile with popular notions of creativity and authenticity (cohen, ) . furthermore, due to rising rents in gentrifying areasironically often the places popularised by creatives -musicians and small-scale venues are struggling to make ends meet (gibson and homan, ; grodach, ) . as roberts ( : ) argues, music is often used in a process of normalisation that benefits commercial and state actors in a city: "an exploration of the process of normalisation involves a critical examination of music's relationship with forms of urban hegemony and the processes though which hegemonic actors both shape and benefit from the production of uneven urban geographies. […] i theorise urban normalisation as a set of spatial processes which reproduce the dominant position of both commercial and state actors within the city." in his research, roberts documents how particular music styles (e.g., indie music) have been normalised in the city of birmingham, while the cultural expressions of disadvantaged youth (e.g., grime) are marginalised. writing about a festival in lisbon, nunes ( ) finds that cultural expressions associated with the margins of the city, like graffiti and slams between rappers, can actually also be brought to upper-class neighbourhoods during official events. in this case, the culture of minorities (e.g., migrants and lgbtq people) is institutionalised. nunes ( : ) describes this as practices of 'social control', whereby the cultural expressions of marginalised groups are brought centre-stage "to keep the center far away from the margin." this illustrates how music's role in urban development is connected to the representation of different groups and their socio-spatial identities. as well as using and developing urban space, live music also plays a role in how cities are represented and imagined through narratives. music performances, venues and festivals are part of the stories that are told about cities by media, local governments and citizens. narratives give meaning to places by connecting their past, present and future (jensen, ; van der hoeven, ) . urban branding and heritage activities are discussed in this article as two narrative practices in which live music often figures prominently. in both cases, it is important to acknowledge the multiplicity of narratives and the range of 'storytellers' involved, including official actors (e.g., urban marketing departments) and grassroots initiatives (e.g., city guides) (brunow, ) . furthermore, narratives can also use a range of media (e.g., social media, documentaries and radio shows) to mark spaces as connected to localised meanings and identities (maalsen & mclean, ; wood et al., ) . urban regeneration is not just about physical interventions in cities; it also has important intangible dimensions such as the ways in which urban spaces are narrated and perceived. so, in order to develop derelict neighbourhoods, for example, it is vital that they are considered to be potentially attractive places in which to live, visit, or invest. urban branding uses positive representations of a city to shape such perceptions, foregrounding the possibilities of a particular place. bottà ( ) , for instance, explains how helsinki was portrayed in its urban branding as a 'rock city' with a lively underground scene. this way of narrating the city aimed to also put 'non-tourist districts' on the map as interesting places to visit, thus diversifying how it is understood. according to bottà ( : ) , this helps to overcome a division between a "culturally loaded city centre" and its "not culturally loaded" surroundings: "the city's cultural territory is extended well beyond the usual borders, both in a symbolic and geographic dimension." similarly, cultural events such as festivals can be used to increase the awareness and appeal of particular urban areas for future development: for example, the european union's european capital of culture programme uses cultural events in its urban branding of cities (cohen, ) . such urban branding practices often tie in with the popular music heritage of cities (oakes & warnaby, ) , which relates to the tangible and intangible elements of the music cultures with which people identify and seek to preserve and pass on to future generations (bennett, ) . examples are venues with a strong legacy and particular festivals that have become annual traditions. the popular music heritage of cities can be narrated through mediums like tourist brochures, exhibitions and documentaries. this heritage fosters a sense of belonging and place attachment ( van der hoeven & brandellero, ) . indeed, the heritage value of a venue can be an argument for its preservation when it is threatened by encroaching development or gentrification (ross, ) . it is vital to recognise the plurality of narratives associated with a place in relation to both music's role in urban branding and music heritage (brunow, ; jensen, ) . otherwise, the dominant narratives of a city overshadow other representations and understandings of value. in liverpool, for example, the histories associated with three popular music venues (the cavern club, eric's club and cream) dominate accounts of its popular music heritage: "these venues provide landmarks that have come to represent significant moments in liverpool's musical heritage, linked closely to the city's social, cultural and economic landscapes during the s, s and s." (lashua et al., ). the authors argue that this perspective neglects other narratives, such as those associated with minorities or emerging scenes. similarly, mercado-celis ( ) contends that memories are often attached to iconic venues, meaning that the rich musical activities taking place outside the central neighbourhoods are overlooked. acknowledging the plurality of narratives is essential, because these representations feed back into how cities are performed and developed. the urban branding and popular music heritage of cities become part of people's musical pathways and the promotion of neighbourhoods. the stories told about cities thus ultimately shape how they are redeveloped and for whom, suggesting that the three dimensions of live music's spatial value are interrelated and dynamic. this study is part of a bigger project on live music, and builds on our earlier research on its social and cultural values in an urban context (van der hoeven & hitters, ). that research involved an analysis of live music strategies and policy documents from different countries. the documents revealed how diverse actors (e.g., local governments, consultancy firms and music industry organisations) understand the value of live music and the ways in which it can be supported. our analysis identified the emergence of a separate value representing the impact of live music on our experiences of urban spaces, and this has therefore been conceptualised further in the current study. we have added four reports to our previous sample (appendix a). we have also conducted in-depth interviews with event organisers, directors of venues hosting popular music and real estate experts (appendix b). a purposive sampling strategy was adopted to select respondents with relevant expertise on the issues arising from our research questions. in particular, we aimed to have a diverse sample to reflect the interdisciplinary nature of the notion of spatial value itself. these interviews allowed us to achieve a more in-depth understanding of the connections between live music and the built environment. in accordance with our university's ethical guidelines, we agreed to not disclose the respondents' names. the reports and interviews were subjected to a thematic analysis using the qualitative data analysis software, atlas.ti. our analysis was informed by the ecological approach to live music adopted in our project. this is a holistic perspective on urban live music ecologies, with the focus on the relationships between different actors, both in and outside the live music sector (behr et al., a; van der hoeven & hitters, ) . in particular, we concentrated on the different factors that enable and constrain spatial value. these were coded using an open-coding strategy in which we labelled relevant segments from the text (boeije, ) . in the next step of the axial coding, we grouped related codes and created categories, before going on to integrate the results. this produced several main themes, which we discuss in this paper (see table ). our analysis is used to examine challenges to spatial value (i.e., the impact of and on the environment) and measures to support it (i.e., building networks, establishing strategies and creating and sustaining places for live music performances). the spatial value of live music emerges in the interplay between live music stages and its urban environment, which is both enabling and constraining. live music always takes place somewhere and so is affected by its environment. as a result, this section discusses the challenges to achieving spatial value, distinguishing between the impact of and on the urban environment in which live music is embedded. the changing uses of urban space around live music stages has a significant effect on the opportunities to perform. in the process of gentrification, affluent people and businesses find their way to popular neighbourhoods. this leads to rising rents, which is particularly challenging to grassroots venues working with small budgets (webster et al., ) . the following quote from rotterdam's popular music policy illustrates how the growing popularity of this city puts pressure on cultural uses of urban space: "this city used to have sufficient affordable spaces for artists and other creatives. however, the development of rotterdam and its growing popularity has an impact on the real estate market." (city government of rotterdam, : ) the mastering of a music city report, published by the international federation of the phonographic industry (ifpi) and music canada to support musical activities in cities, argues that this development might result in fewer opportunities to perform: "in many areas, redevelopment has led to the closure of iconic venues -even some world famous ones -that draw tourists. this has a two-fold negative impact. first, it threatens to eliminate key differentiators that help a city stand out. second, it reduces the spaces available for performance, impacting the overall level of live music activity." (terrill et al., : ) even though culture has a positive social and cultural impact on cities, it is difficult to sustain cultural venues in an environment focused on commercial gain. residences have a higher return on investment than cultural uses, with the consequence that the number of affordable buildings available for cultural functions falls. according to shaw ( : ) : "the driving neoliberal imperative for highest and best use of land is anathema to creative subcultures." as a real estate expert explains in the following quotation, the profits from buildings are more important to private developers than their wider cultural impact: "that's a vital difference between commercial developers and what we do in the projects commissioned by municipalities. for a commercial developer, the value of the spin-off is in fact value for someone else, unless they can develop a lot around the plot as well." (interviewee , real estate consultant) • using special designations (i.e., a heritage status or creating entertainment precincts) all dutch quotations have been translated by the authors. in other words, unless there is a recognition that culture may actually increase the appeal of a place, there is no great commercial incentive to invest in less profitable cultural uses. these challenges of gentrification are most likely to arise in popular areas in central districts. in contrast, venues in less popular neighbourhoods may have the opposite problem of a lack of activity around their buildings. mixed uses in areas are thus essential for generating enough vibrancy and street level activity (brown et al., ) . less accessible public transport may also be an issue in the urban periphery, where there are also fewer bars and restaurants. indeed, it has been found that the (lack of) availability of parking spaces and public transport options at night affects decisions about whether to go to concerts (whiting & carter, ) . the popularity of inner-city living increases densification, causing tensions between residents and live music activities (shaw, ) . as argued in the mastering of a music city report (terrill, hogarth, clement & francis, : ) : "beyond the challenge of gentrification, […] the music businesses that initially made an area attractive are often perceived as unwanted neighbours." indeed, the issue of noise is a recurring theme in both the reports and interviews analysed for our study. open-air concerts or performances in venues with poor sound insulation often cause a nuisance to residents. even the loading and unloading of equipment can cause problems, as this venue owner explains: "in every new venue, trucks can park inside to load and unload. well, we don't have that and you know for a fact that people, even if they haven't been drinking, they have performed, they will have a beer or just sit with a soft drink. as soon as they pack their stuff it's already past midnight. well, then they're standing outside, actually shouting because they've been in a noisy environment the whole night." (interviewee , director of a music venue) beyond noise, concerts can also cause parking problems in neighbourhoods or lead to anti-social behaviour by attendees. indeed, regardless of whether these issues are actually relevant, venues often have a negative reputation, making residents hesitant about live music activities. open-air concerts in public parks and on greenfields cause a specific set of problems. in rotterdam, for example, there are discussions about the unavailability of public parks because of the growing number of festivals, with commercial events in particular meaning that these locations are no longer accessible to residents for the duration of a festival (venema, ) . furthermore, some have concerns about the negative impact of live music on flora and fauna; for example, festival sites can experience damage to plants and wildlife may be disturbed (webster & mckay, ) . the previous section demonstrates that spatial value cannot be taken for granted and is not self-evident. indeed, if live music's spatial embedding is to be enhanced, its values need to be recognised by, among others, residents and urban developers. the following sections therefore discuss how the spatial value of live music can be supported in urban planning and policymaking by building inter-disciplinary networks, establishing strategies, and sustaining places for live music. providing support for spatial value requires a multifaceted approach, because the dimensions of performing, developing and narrating the urban space rely on a wide range of different actors. as well as physical facilities, cultural industries need a 'soft infrastructure' that connects people and organisations (brown et al., : ) . urban live music ecologies have a networked structure, in which different actors participate to value live music (van der hoeven et al., ) . this involves negotiation with people inside the music sector (e.g., bookers and managers), as well actors in other domains (e.g., regulators and policymakers) (behr et al., a) . spatial value can be linked to different departments, even within local governments. according to rotterdam's music strategy ( : ): "popular music (pop culture) connects not only different parties or cultural makers, but also different policy domains: culture, spatial planning, economy, city marketing, tourism, wellbeing, youth, education and integration." these different departments can have conflicting interests, such as supporting talent development (culture), increasing the housing stock (spatial planning) and tourism (economy and city marketing), or improving citizens' social capital (wellbeing, youth, education and integration). our analysis found that supporting live music's spatial value requires people and organisations to find common ground between the interests of actors within diverse networks, including those like policymakers, business and the cultural industries (grodach, ) . although the actors in these urban networks may have different goals, they often share an attachment to a city. various respondents stressed that a shared sense of pride in local accomplishments is a good starting point for conversations about the value of culture. "not everyone's interested in [the value of culture] of course. that has to do with education as well. i mean, i'm not going into that issue, but i do try to show how it can benefit them. for me, the most important thing is what it can mean for the city. that's the common denominator, the way of getting different parties together. why are we doing this? not for ourselves, but for the city." (interviewee , creative producer) "interviewer: in the policy plan it said you told companies about the contribution of culture to urban development. i guess that's not an easy story to tell?" respondent: well, we focused on the gut feeling, the sense of pride in the city that many companies also have. we were trying to address this gut feeling: 'we're located here in this legendary neighbourhood, which has reached its nadir, a no-go zone at the moment. we're going to do pioneering work and you're going to help. we're going to make it better again by means of a theatre.' that's what we really focused on. of course, it helped [that] they knew me and, i guess, trusted me." (interviewee , director of a theatre) of course, connecting the interests of different actors through a shared attachment to a place is only possible if the people involved identify with it. for this reason, some interviewees stressed the risks posed by foreign investors, who may buy buildings without feeling responsible for the direct surroundings. similarly, event organisers based in a city away from where, for example, a festival is taking place might be less inclined to care about the concerns of local actors. it is, however, important to invest in the relationship with a neighbourhood if complaints are to be avoided and the social impact of events enhanced. indeed, there is a need to also include residents in any multidisciplinary networks. our respondents stressed the importance of communication about activities and, if possible, involving residents in any planning. this is a long-term process, because there is a risk of losing support without pro-active communication in the early phases of projects. one real estate expert discussed how residents may use social media to protest about new venues: "all of a sudden there might be a neighbourhood coalition against your plans. if that's the time you start your communication, it's already - to them, let's say." (interviewee , senior project manager real estate sector) a common strategy for representing the interests of the music sector in these networks is to establish music advisory boards and/or appoint night mayors or night czars. such boards are advocacy organisations comprised of a range of actors from within the music sector, while night mayors or night czars are individuals who liaise between different stakeholders in the night-time economy (e.g., venues, residents and local government). the mastering of a music city report argues that music advisory boards have three core functions: creating a consensus within the music sector, providing advice on regulation and acting as a contact point for stakeholders: " [i]f there is no consensus and collaboration in the music community, it is inevitably harder for governments to understand the unique challenges faced by the sector, and governments will be far less motivated to make positive changes." (terrill et al., : ) in other words, music boards can be central actors in linking the various stakeholders involved in negotiating the spatial value of live music. in the view of our respondents, the challenges discussed in this paper require long-term strategies: without dedicated policies on the connections between music and the urban space, the availability of stages for events is often at risk, as discussed above. city strategies on popular music help to ensure that new talent has the space to experiment and be inspired by other musicians. of course, the music advisory boards discussed in the previous section can also play a vital role in establishing such strategies. an important starting point is to map the places that currently exist for performances (terrill, hogarth, clement & francis, ) . this allows stock to be taken of the diversity of stages in terms of venue size, genres and location. this data can be substantiated by interviews with relevant stakeholders in order to understand the challenges present in specific live music ecologies. this provides insight into how, for example, various regulations, including those related to parking permits, opening hours and alcohol licences, can have an impact on music businesses. a strategy can propose specific policies and financial measures based on a needs assessment. a common policy instrument is to use subsidies, tax-breaks or micro-loans to sustain specific segments of music ecologies. these are particularly useful for supporting the grassroots level of the music sector. showcase festivals, award shows, small venues and talent development organisations are important for emerging musicians wanting to develop their skills and build-up a following. however, organisations focusing on young musicians tend to operate on small budgets, as is also the case for music organisations with a social mission that involves community work. it is helpful to have a dedicated department or music office within a municipality when it comes to implementing any music strategy. a single point of contact makes it easier for the music community to navigate regulatory issues (terrill, hogarth, clement & francis, ) , while such a department can also oversee a city's music policy and liaise with the relevant board. some cities even have a specific department focusing on events. in rotterdam, for example, rotterdam festivals supports cultural organisations by conducting research on audiences, managing the festival calendar, providing subsidies and sharing relevant information. they have also created location profiles that contain conditions and instructions on how specific spaces in the city can be used for events. notwithstanding the importance of a music strategy, our analysis has demonstrated that there is a sense of contingency in how this is actually played out in cities. of course, not everything can be approached from the top down. indeed, in reality, a music strategy needs to support the bottom-up creativity of cultural entrepreneurs and organisations. ultimately, it is the music community that is best placed to connect to audiences and their tastes, not a municipality. furthermore, the contingency of achieving spatial value follows on from the reliance on wider political and economic conditions. of course, investments in culture require political support from city councils. in this context, culture is in competition with other policy domains like healthcare and housing, making it more difficult to allocate money to culture at times of economic austerity. nevertheless, to some extent, the - financial crisis also proved to be helpful for realising spatial value. the following quote exemplifies how there were more empty spaces available for temporary use, such as pop-up programmes on cultural events: "the financial crisis meant that commercial property developers and investors couldn't carry on with the transformation of buildings, because they weren't able to acquire the necessary loan capital. this meant that all those buildings owned by investors, developers and social housing corporations were put on hold. well, so if you had a good network [as an organisation supporting creative incubators], you could make deals with commercial developers." (interviewee , senior project manager, real estate sector) similarly, a director of a venue in an adapted building commissioned by the local municipality explains how construction companies worked for much lower prices during the financial crisis: "the local government was able to get this venue at a good time. they invited the tenders almost years ago. this was exactly the moment the financial crisis began, so all the construction companies were looking for work. this meant they were willing to work for lower amounts. the local government got a very nice building for relatively little money." (interviewee , director of a music venue) during subsequent periods of economic growth, the number of vacant spaces declined again, making it more difficult to find cheap areas for the performance of culture. at the same time, the many new developments in a booming property market compound the existing pressure on the urban space. the final section of this article will therefore focus on how places for performing live music can be created and sustained. as discussed in the literature review, the spatial value dimension of performing in the urban space relies on the availability of music stages. as a result, the most important way of supporting spatial value is creating and sustaining such spaces. of course, this vision should be part of the music strategy discussed above. this will be discussed separately in this final section, given its key role in supporting spatial value. creating and sustaining places for live music goes beyond music and cultural policy, influenced as this is by urban planning decisions. this section will consequently focus on opportunities to secure spaces, address noise issues, limit gentrification and introduce special designations for live music spaces. the strategies discussed in the previous section begin with the mapping of the places that already exist for the performance of live music. the results of such an inventory may highlight the need to identify new spaces where venues can be created or festivals hosted. one way of doing this is to use government-managed buildings for creative purposes (hollands, ) . amsterdam, for example, facilitates cultural breeding spaces as a way to retain cultural activities in the gentrifying city (shaw, ) . another approach is the mapping of underused spaces, with areas marked for future development lent to live music organisations on a temporary basis, but for enough time to ensure that investments can be recouped by cultural entrepreneurs. music can also form part of new urban developments right from the start, but it is essential that cultural spaces are included in initial plans and negotiations, otherwise the incentive is for commercial developers to focus on more profitable residential spaces. as the literature review on developing the urban space demonstrates, live music can increase the appeal of new developments. this is underscored by the following respondent, who talks about a neighbourhood which, in her view, lacks cultural facilities: "nothing happens there, only living and working. not even working, almost only residential buildings in fact. it's a really sleepy neighbourhood, which should really be avoided. mixed neighbourhoods are important." (interviewee , creative producer) similarly, live music can also be taken into consideration in the construction of public spaces (auckland unesco city of music, ; live music taskforce, ), for example by installing a base level of infrastructure for outdoor concerts. noise issues are the most common problem when it comes to existing spaces for live music, as discussed in the section concerning the challenges that must be faced before achieving spatial value. it is increasingly recognised that encroaching residential developments pose a threat to the cultural life of cities. this requires measures to ensure that music spaces and residents can co-exist relatively peacefully in urban environments. tensions can sometimes be resolved by mediation between venues and neighbours, or by ensuring that prospective purchasers of homes are told in advance about how these spaces are used. burke and schmidt ( ) , for example, discuss an approach that real estate agents can adopt to enable potential buyers to listen to the soundscapes in an entertainment precinct. a more structural solution is the agent of change principle (ross, ; shaw, ) , which has been adopted in australia and the united kingdom. this urban planning measure puts the responsibility for addressing sound issues on the newcomer to an area (i.e., the agent of change), rather than on those in charge of existing cultural spaces, which should prevent the closure of long-standing venues after complaints from neighbours in new residential buildings. another important way of supporting existing live music spaces is to mitigate the negative consequences of gentrification. as discussed in the literature review, live music can play a vital role in place-making and increasing the appeal of an area. however, the risk is that these cultural organisations are forced out after rents rise. using case studies in melbourne, shaw ( : ) argues that city councils must make a choice between maximising land value or supporting socio-cultural goals: "they can pursue the usual urban renewal/economic development strategy, which creates a safer environment for capital investment and increases opportunities for residential development, in which case the indie creative subcultures that both councils celebrate will be displaced far more rapidly and effectively than they anticipate. or they can grapple with the possibility that maximising the value of land in their municipality not be their primary objective." even if local governments are selling buildings to private parties, they can include conditions on the ways in which they will be used. as an example, contracts, zoning plans or ground lease conditions could incorporate requirements that spaces need to fulfil cultural functions. alternatively, successful cultural organisations in an area can be encouraged to remain by enabling them to buy their building, perhaps as a co-op where different organisations work together (hollands, ) . finally, live music spaces can be protected by changing the ways in which they are classified. this can be done by recognising the unique contributions made by a building or area to the social and cultural life of cities. as discussed in the literature review, the dimension of narrating the urban space underscores how urban branding and heritage activities give meaning to the built environment. venues with a strong public impact and history could be given a similar building classification as theatres, or even a heritage designation status. however, while the latter solution protects the building itself, the continuation of music activities will still rely on the occupants or the owner of the building (terrill et al., ) . furthermore, some governments have a protected status for buildings of community value, such as the asset of community value process in the uk (davyd et al., ) . it is also possible to define entire areas as entertainment districts using zoning plans. these can have a higher sound tolerance, longer opening hours for venues and special parking permits for musicians (terrill et al., ) . an advantage is that many of the nuisance issues are then concentrated in a particular area, making them easier to control. moreover, the different organisations can engage in shared promotional activities, making the area attractive to potential visitors. however, an important drawback of concentrated entertainment districts is that many parts of a city can be left with no provision for live music (burke & schmidt, ) . certainly, social and spatial links between different areas are essential to cater for diverse urban communities in a thriving urban live music ecology (brown et al., ; mercado-celis, ) . the aim of this study has been to conceptualise the spatial value of live music and explore how it can be supported through cultural policies and urban planning. taking an interdisciplinary approach, the paper contributes to the field of urban studies by drawing on literature from music and cultural research. spatial value is defined as the relationship between live music and the built environment, which manifests itself through the dimensions of performing, (re)developing and narrating spaces. performing the urban space concerns the ways in which a city is physically used to stage concerts and create musical pathways; redeveloping refers to the role of live music in the making and regeneration of space; and narrating focuses on live music as part of the stories told about cities. defining the spatial value of live music is becoming an increasingly important task given the threats posed to it in cities. table provides an overview of the main research findings. the focus is on the challenges likely to be faced when seeking to achieve spatial value and the ways in which this process can be supported. the paper has demonstrated that the spatial value of live music cannot be taken for granted, affected as it is by wider political and economic forces. important challenges concern the impact of the environment in which live music is embedded (e.g., gentrification), as well as the nuisance music might cause (e.g., noise and anti-social behaviour). in addressing these issues, it is important to make a place for music. doing so not only means having a physical space, but also recognising this space in urban policy and planning. in order to support live music in all its diversity (e.g., different genres, experimental sounds and artists at various stages of their career), its value needs to be acknowledged by the diverse stakeholders involved. establishing strategies and creating and sustaining places for live music requires strong networks within the live music industries and connections to networks outside the music business. such strategies can include financial instruments (e.g., subsidies), measures to mitigate the effects of gentrification (e.g., supporting socio-cultural values instead of maximising profits), solutions for noise issues (e.g., the agent of change principle), and using special designations for live music spaces. although these strategies allow for a systematic approach to achieving spatial value, we do not intend to suggest that live music can just be planned in a top-down manner. indeed, it is essential that strategies make room for bottom-up initiatives, creativity and entrepreneurship. in the conceptualisation of spatial value, we emphasise its multiplicity, as a wide range of grassroots and official actors participate in the valuing of urban spaces. furthermore, it should be noted that the spatial value of live music develops over time, often in unexpected ways due to social, technological and economic developments. this value builds on the musical heritage of a city; it also requires diverse spaces for experimentation by artists in order to guarantee a lively music culture for the future. graves-brown ( ) reminds us that music is both an event and an action. it is also dynamic and complex, like the cities in which it is performed (cohen, (cohen, , . indeed, music stages are often temporary, such as festivals or pop-up venues. these temporary stages are valuable in terms of experimentation and diversifying the music provision. understanding urban live music ecologies as dynamic provides a counterweight to narratives about the fall in the number of live music venues. arguably, the coming and going of stages is part and parcel of urban life. nevertheless, it is essential that successful projects can contribute to the social and cultural life of cities in a sustained manner. future research may shed light on what is a good balance between temporary and fixed venues. urban planning strategies to mitigate the negative effects of gentrification also require more attention. of course, spatial value is contextual, relying as it always does on local geographical, political and economic conditions. as a result, case studies can further enhance our understanding of supporting spatial value in specific local settings. as we have limited the scope of this study to popular music in cities, future research could be extended to cover different styles of music and non-urban and rural spaces. finally, further research is required to understand the spatial value of live music in a post-covid world. shortly after the data collection element of this paper ended, the live music sector stalled due to the coronavirus. of course, the cancellation of so many events will have economic repercussions for numerous actors in the live music ecology, putting even more pressure on small music venues. the spatial consequences are hard to predict, but an early study of the impact of covid- on the public space suggests that it could lead to an aversion to being in large crowds, requests for improved ventilation, more outdoor spaces in venues and the inclusion of health criteria in the design process (honey-rosés et al., ) . inevitably, some spaces can satisfy such demands more easily than others. meanwhile, new spaces could emerge as locations for concerts, changing how the urban landscape is performed, developed and narrated. as an example, the sofar sounds initiative books intimate concerts in people's homes , while illegal raves took place in urban outdoor spaces during lockdown (marshall et al. ) . perhaps the crisis will lead to the repurposing of vacant buildings for music activities. finally, the experiments with online live music that occurred during the lockdown could lead to new virtual spaces for music-making, which will require studies to adopt innovative methodologies like netnography (maalsen & mclean, ) . post-covid concerts could include hybrid forms of online and physical activities, as festivals and venues may increasingly support the streaming of concerts, the building of virtual worlds and online social interactions. of course, these predictions are highly speculative, but nevertheless suggest that covid- could change how the spatial value of live music is achieved in the 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a trialectic analysis of the recent developments of cultural venues in amsterdam valuing live music: the uk live music census access, place and australian live music the art of doing (geographies of) music music/city: american festivals and placemaking in austin, nashville, and newport the sites and sounds of placemaking: branding, festivalization, and the contemporary city this work was supported as part of the project staging key: cord- -javtkg m authors: calderón-garcidueñas, lilian; torres-solorio, ana karen; kulesza, randy j.; torres-jardón, ricardo; gonzález-gonzález, luis oscar; garcía-arreola, berenice; chávez-franco, diana a.; luévano-castro, samuel c.; hernández-castillo, ariatna; carlos-hernández, esperanza; solorio-lópez, edelmira; crespo-cortés, celia nohemí title: gait and balance disturbances are common in young urbanites and associated with cognitive impairment. air pollution and the historical development of alzheimer’s disease in the young date: - - journal: environ res doi: . /j.envres. . sha: doc_id: cord_uid: javtkg m to determine whether gait and balance dysfunction are present in young urbanites exposed to fine particular matter pm( . ) ≥ annual usepa standard, we tested gait and balance with tinetti and berg tests in clinically healthy subjects, age . ± . y who were residents in metropolitan mexico city, villahermosa and reynosa. the montreal cognitive assessment was also applied to an independent cohort n: , age . ± . y. in the cohort, . % and . % had abnormal total tinetti and berg scores and high risk of falls in . % and . % respectively. bmi impacted negatively tinetti and berg performance. gait dysfunction worsen with age and males performed worse than females. gait and balance dysfunction were associated with mild cognitive impairment mci ( . %) and dementia ( . %) in / and cognitively intact subjects had gait and balance dysfunction. seventy-five percent of urbanites exposed to pm( . ) had gait and balance dysfunction. for mmc residents-with historical documented alzheimer disease (ad) and csf abnormalities, these findings suggest alzheimer continuum is in progress. early development of a motoric cognitive risk syndrome ought to be considered in city dwellers with normal cognition and gait dysfunction. the ad research frame in pm( . ) exposed young urbanites should include gait and balance measurements. multicity teens and young adult cohorts are warranted for quantitative gait and balance measurements and neuropsychological and brain imaging studies in high vs low pm( . ) exposures. early identification of gait and balance impairment in young air pollution-exposed urbanites would facilitate multidisciplinary prevention efforts for modifying the course of ad. gait, equilibrium and postural disorders are linked to neurological and neurodegenerative pathologies. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] gait is a complex activity requiring the activation of the cerebral cortex, basal ganglia, cerebellum, brainstem, spinal cord and the musculoskeletal system. [ ] [ ] [ ] [ ] [ ] independent papers by kaoru takakusaki, klaus jahn and anat mirelman et al., [ ] [ ] [ ] extensively discuss human locomotion and the key regions associated with gait and posture i.e., the mesencephalic locomotor region (mlr) and its projections to the pontomedullary reticular formation; the subthalamic locomotor region (slr) and the cerebellar locomotor region (clr). jahn et al., studies in imaging human supraspinal locomotor brainstem and cerebellum are of particular interest in this paper given their clinical relevance and the connections of gait initiation and speed regulation pacemakers with anatomical structures such as the inter-fastigial cerebellum, midbrain tegmentum, cerebellar vermis and pontine reticular formation. strikingly, motor imagery and actual movement activate not only premotor and supplementary motor areas, but also cingulate and parietal cortical areas. the importance of postural control and cerebellar gait input has been put forward independently by armstrong and orlovsky , and support the integration of widespread locomotor structures from proprioceptive, exteroceptive, visual, vestibular, cerebellar, dorsal brainstem and cortical input for gait initiation and modulation. thus, it is not a surprise gait pathology is described in the elderly especially in relation to neurodegenerative and dementia pathologies. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] associations between gray matter volume and gait parameters in mild cognitive impairment (mci) patients (temporal lobe) and controls (frontal areas in healthy elderly), suggest a relationship between dementia-related pathology and gait dysfunction that becomes clear in alzheimer's disease (ad) patients when applying the dual-task gait performance testing. patients with dementia had significantly higher dual-j o u r n a l p r e -p r o o f task cost (dtc) in counting gait and naming animals conditions vs individuals with subjective cognitive impairment (sci) and mci. tian et al., have shown that greater rate of increase in lap time variability from a -m walk differentiates individuals who eventually develop mci/ad from controls, supporting early pathology likely impacts the automaticity of walking. motoric cognitive risk syndrome (mcr) characterized by subjective cognitive complaints and slow gait is common across the world with a prevalence of . %. gait abnormalities are common in mcr and are associated with accelerated functional decline and gray matter atrophy in motor, insular and prefrontal cortex linked to the control aspects of gait such as motor planning and modulation. muurling et al., have shown an association between gait specific measures related to pace and rhythm, cerebrospinal fluid (csf) hyperphosphorylated tau and dementia. muurling's work is key for this investigation given that metropolitan mexico city residents show evidence of alzheimer's disease in / forensic autopsy cases age . ± . y, csf aβ - , bdnf, α-synuclein, and inflammatory markers are evolving in young urbanites showing underperformance in cognitive processes, and abnormal brainstem evoked potentials. [ ] [ ] [ ] [ ] [ ] [ ] [ ] these findings support a spectrum of cognitive, imaging and gait abnormalities in the elderly population and that gait abnormalities could indeed be an early indication of a high risk for mci and dementia. it is striking there are very few gait studies in young adults if we indeed recognize neurodegenerative processes take several decades to evolve , and if biologically defined ad is more prevalent that clinically defined ad. heijnen and rietdyk in a study of undergraduate students found falls are the third leading cause of unintentional injuries for young adults ages - y. these young adults fell once out of every perceived slips and trips -this j o u r n a l p r e -p r o o f is not a trivial problem for a population with no risk factors for diseases affecting gait and dynamic equilibrium. given these findings we are concerned young metropolitan mexico city (mmc) residents exposed to concentrations of fine particulate matter (pm . ) above the united states environmental protection agency (usepa) standard and in conjunction with a historical documentation of alzheimer pathology progressive changes , we hypothesized that alzheimer neurodegenerative processes given rise to cognitive deficits, could also involve gait and balance dysfunction, particularly because we have extensively documented brainstem hyperphosphorylated tau, beta amyloid and alpha-synuclein in pediatric and young adults mmc forensic autopsies. , the purpose of this study was to document gait and balance alterations and cognitive deficits in a cross sectional study of clinically healthy adults, average age . ± . y residents in mexican cities with concentrations of fine particulate matter pm . above the usepa annual standard. our first aim was to score a selected balance scale: berg , and a performance-gait and balance scale: tinetti , in our young cohort. the second aim was to measure cognitive performance plus tinetti and berg in an independent cohort (n: ) to determine if an association between gait, balance and cognition deficits is present given the ad continuum described in similar age mmc cohorts. , the montreal cognitive assessment version , translated into spanish, was our selected instrument. , moca covers several j o u r n a l p r e -p r o o f cognitive domains including episodic memory, language, attention, orientation, visuospatial and executive functions and has been validated in mexican populations. [ ] [ ] [ ] [ ] [ ] early identification of gait and balance impairment in young air pollution-exposed urbanites would facilitate multidisciplinary prevention efforts for modifying the course of ad. the mexican urban areas selected were metropolitan mexico city (mmc), villahermosa and reynosa. selection was based on geographic location, urban characteristics and stable air pollutant levels in the last decades. the focus was on pm . (≤ . µm particles) and we selected to illustrate their behavior for -the year previous to this clinical study-based on -hr and annual usepa standards. supplemental table shows a summary of the main characteristics of the study urban areas, sources of particulate matter and pertinent references. figure shows as shown in figure , the higher daily pm . averages were registered in mmc. the j o u r n a l p r e -p r o o f normal gait, ataxic gait, antalgic gait, cautious gait, frontal gait, hemiparetic gait, spastic gait and shuffling gait as per the guidelines for gait assessment in the canadian consortium on neurodegeneration in aging. tinetti gait and balance , evaluations consisted of two parts. the first part is a static examination of standing that includes items: standing position, ability to stand up and to resist external destabilizations. each item is scored from (normal) to (abnormal). the second part is based on a gait observation with nine items, scored as normal to . the gait score is and the balance score is . the berg balance scale (bbs) , consists of items assessing the ability to stand up and to maintain standing position despite perturbations. each item is scored from (unable) to (safely done) with a maximum score of . we had an independent clinically healthy cohort n: , age . petersen original delayed recall score plus vis, eis and lis were also used. we first calculated the summary statistics of the berg and tinetti scores in the cohorts. then, we tested the equality of mean scores of each meaningful pair. for the total tinetti score we used ≥ as of low risk of falling, - moderate risk and ≤ as high risk. for the bbs we used - as normal, ≤ abnormal. we created three cohorts based on moca: normal, mci and d. the cut-off points are based on total moca scores, normal ≥ , mci - , d ≤ . we tested the equality of mean scores of each meaningful pair. we calculated the index scores in each j o u r n a l p r e -p r o o f cohort as well. we also fit a multiple linear regression of the total tinetti, berg and moca score on age, bmi, gender, and education years. we ran the regression models for each of the aforementioned groups. all statistical analyses were made using excel and the statistical software 'r' (http://www.r-project.org/). all participants were residents in urban areas with concentrations of pm . above the annual usepa standard. mmc residents were exposed to high concentrations of pm . , including secondary aerosols and ozone for the last years. historically, the problem of air pollution in mmc we analysed the results of both tests by residency ( table ).the lowest score for tinetti gait was in villahermosa, a city with significant oil industry-associated air pollution, average low cognitive scores in the range of dementia and high bmi in young adults. the lowest score of tinetti balance was for mmc residents. reynosa residents, with the lowest air pollution concentrations had the highest scores for both tests. gait and balance dysfunction are present in ~ % of seemingly healthy young adults age . ± . y residing in mexican cities with concentrations of fine particulate matter pm . above the current usepa annual standard. high risk of falls was detected in . % and . % of them using tinetti and berg instruments, respectively. young adults are showing higher fall risk and significant cognitive deficits in the absence of risk factors commonly associated with cognition impairment and dementia at younger ages. outstandingly, these young adults with college education belong to the same socio-economic status as the mmc subjects ≤ y staged for ad with alzheimer continuum. , , in the forensic autopsy study , age and cumulative lifelong concentrations of pm . were significant for developing nft v. in the same autopsy cohorts, magnetic, combustion-derived nanoparticles are associated with early and progressive damage to the neurovascular unit, making the issue of nanoparticulate matter air pollution in mmc residents relevant to our discussion. we have cognitive complaints-described in elderly cohorts. , , our findings in the young cohort with gait and balance abnormalities ought to be discussed on the bases of the extensive literature available in gait, mobility, cognition, alzheimer and air pollution. first, there is no question about the high risk of falls in older people and the validity of paradigms linking shared brain pathways in mobility, falls and cognition. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] key to this discussion is the association between specific gray matter networks, normal pace walking speed, dual-task costs and different cognitive domains and the strong evidence that shared neural systems responsible for gait speed and processing speed are indeed subjected to age and dementia-associated pathological changes. on the other hand, the extensive work on the motoric cognitive risk syndrome (mcr) defined as a pre-dementia syndrome characterized by subjective cognitive complaints and slow gait, the association between gait decline and mild cognitive impairment (mci) and the cognitive and motor trajectories in their path to dementia are obligated topics in this discussion. [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] montero-odasso et al., paper is critical. the authors did a y prospective longitudinal study of adults ≥ y without dementia at day and defined j o u r n a l p r e -p r o o f motor and cognitive decline in those who progressed to dementia versus those who did not. the authors concluded decline in serial measures of gait velocity, had a higher attributable risk for incident dementia than did cognitive decline alone and the highest risk for dementia was in subjects with a decline over time of both gait velocity and cognition. is not confined to supratentorial regions, it also involves the brainstem tracts and nuclei. indeed, the significant alterations to the brainstem auditory evoked potentials are related to the damage combination of wm tracts and auditory nuclei, a finding evolving in mmc residents as their aged and one of our proposed non-invasive markers of alzheimer continuum. , metabolic and genetic factors also have to be considered when we analyzed motor and cognitive decline and the work of sathyan et al., nanoparticles to the brain. , , , , , beauchet et al., put forward a biologically plausible explanation for the correlation between greater subvolumes of the somatosensory cortex and hippocampus reported in fallers compared to non-fallers: a possible brain compensatory mechanism involving spatial navigation and integration of sensory information. indeed, in explaining increased gain in the auditory pathway (measured as brainstem auditory evoked potentials) in mmc residents we strongly supported compensatory plasticity, neuroinflammation, and ad continuum as strong players in mmc residents. we have to fully agree with beauchet et al., that the mcr-related smaller global and regional gray matter volumes involving premotor and prefrontal cortices, could be used to predict cortical neurodegenerative changes. based on our mri/mrs studies in mmc residents, we also are of the opinion volumetric changes in hippocampus and entorhinal cortex are not early findings and we have a higher likelihood of detecting mrs changes, as shown in mmc young residents. , the key question to be asked for metropolitan mexico city residents is why are we seen gait and balance dysfunction in seemingly healthy young adults biological explanation for a possible brain compensatory mechanism has to be entertained. indeed,compensatory plasticity, neuroinflammation, and ad continuum are playing a role in the auditory pathway increased gain over time in mmc residents. .the portal of entry of fine pm and nanoparticles (nps) ought to be considered. the inhalation respiratory portal is important, however the gastrointestinal/neuroenteric portal could also be extraordinary important in some people. the gi system includes an extensive biological barrier, but ingestion of nps will impact the microbiota and mucus and an altered intestinal homeostasis is an expected outcome. nps taken through the gi pathway can access the brainstem directly, we strongly support that in highly exposed pm . populations, clinical gait assessment and quantitative gait parameters should be included in their neuropsychological assessment, along baeps, olfaction and cognition tests. the use of a computerized walkway and the inclusion of key variables for gait (pace, rhythm and variability), stride length, swing time, stride length variability, swing time variability along balance testing ought to be included. the concept of alzheimer's disease as defined by the national institute on aging and alzheimer's association research framework : alzheimer's disease is defined by its underlying pathologic processes that can be documented by postmortem examination or in vivo by biomarkers, is a welcome biologic construct enabling researchers to add variables to the frame work aimed to an accurate characterization and understanding of the sequence of events that lead to cognitive impairment. the fact that biologically defined alzheimer disease is more j o u r n a l p r e -p r o o f prevalent than clinically defined probable alzheimer disease at any age is a crucial piece of information ,one that obligates us to use every potential early marker to identify subjects in the early stages of ad and defining early gait and balance abnormalities is part of the strategy. a major advantage of our research design is the access to mexican subjects with similar socioeconomic status, formal education years, nutrition patterns, etc., enabling us to rule out the possibility that these key variables will modify our results across different urban areas. we selected healthy young individuals and we have a detailed description of ad pathology in consecutive mmc forensic autopsies, ages months to years with no extra-neural pathology, allowing us to put forward direct correlations with the moca results in mmc residents and indirectly with residents across the country. , , the study has shortcomings. our major gap is the lack of funding to purchase a computerized walkway and to do apoe genotyping that will allow us to identify subjects with earlier stages of ad. the association between gait and balance dysfunction with mci and dementia scores in cohorts of y olds supports ad continuum and we need to contemplate an early development of a motoric syndrome in the adults with gait dysfunction and normal cognition. we strongly support alzheimer's disease is preventable in the scenario of air pollution. as such, we enthusiastically endorse screening for gait and balance abnormalities as part of the ad research frame in pm . exposed young adults, children and teens. j o u r n a l p r e -p r o o f gait disorders balance and mobility in geriatric patients : assessment and treatment of neurological aspects the aging vestibular system: dizziness and imbalance in the elderly balance and gait represent independent domains of mobility in parkinson disease abnormality of gait as a predictor of non-alzheimer's dementia impaired perception of 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and frictionderived nanoparticles and industrial-sourced nanoparticles: the culprit of alzheimer and parkinson's diseases the complex genetics of gait speed: genome-wide meta-analysis approach ♦ mexico city urbanites . ± . y had abnormal tinetti % and berg % ♦ high risk of falls in % (tinetti) and . % (berg) is of deep concern ♦gait and balance dysfunction are associated with mci and dementia scores lcg study concept and design, analysis and interpretation of data, writing, drafting and revising the manuscript, study supervision and coordination, funding. akts, rjk analysis and interpretation of data, writing, drafting and revising the manuscript. psm statistical analysis, writing, drafting and revising the manuscript. rtj air pollution sections writing, drafting and revising the manuscript. dacf, sclc, bga, lcgg, ech, esl, ahc, cncc acquisition of data, study supervision and coordination, analysis and interpretation of data. all other authors acquisition of data, study supervision and coordination and revising the manuscript. key: cord- - zwjdlrt authors: xu, yanyan; olmos, luis e.; abbar, sofiane; gonzalez, marta c. title: deconstructing laws of accessibility and facility distribution in cities date: - - journal: nan doi: nan sha: doc_id: cord_uid: zwjdlrt the era of the automobile has seriously degraded the quality of urban life through costly travel and visible environmental effects. a new urban planning paradigm must be at the heart of our roadmap for the years to come. the one where, within minutes, inhabitants can access their basic living needs by bike or by foot. in this work, we present novel insights of the interplay between the distributions of facilities and population that maximize accessibility over the existing road networks. results in six cities reveal that travel costs could be reduced in half through redistributing facilities. in the optimal scenario, the average travel distance can be modeled as a functional form of the number of facilities and the population density. as an application of this finding, it is possible to estimate the number of facilities needed for reaching a desired average travel distance given the population distribution in a city. at a time of the very visible effects of the climate impact on our urban lives, some cities have become unbreathable, and greenhouse gas emissions are produced by buildings heating and cooling networks, and all-round petrol transport. at a time when transport has become the first emitter of co , we need to imagine, propose, other ways of occupying urban space. this calls for a better understanding of the spatial distributions of facilities and population ( ) ( ) ( ) ( ) ( ) ( ) ( ) . the information age and the online mapping revolution allow us to globally study the interactions of humans with their built and natural environment ( ) ( ) ( ) ( ) ( ) ( ) . pioneering work in multi-city studies have uncovered scaling laws relating population to distribution of facilities and socio-economic activities at macroscopic scale ( , , ( ) ( ) ( ) . it has been asserted, for example, that more populated cities are more efficient in their per capita consumption ( , ) and their occupation diversity can be modeled as social networks embedded in space ( ) . yet, a systematic understanding of the interplay of the urban form, their facilities distribution and their accessibility at multiple scales remains an elusive task. at the country scale, when maximizing for the accessibility of population to a fixed number of facilities, gastner and newman demonstrated a simple / power law between the optimal density of facilities d and their population density ρ ( ) . the power law was fitted by allocating , facilities in the continental u.s. using population data within more than million census blocks. in this case, each facility covers an area about the size of a county (∼ , km ). in a follow up study, um et al. proposed distinct optimization goals to differentiate public services, such as fire stations and public schools, from commercial facilities, such as banks and restaurants ( ) . public service facilities aim to minimize the overall distance between people and the facilities, follow d ∝ ρ / . however, in the case of profit driven facilities, which have the goal of maximizing the number of potential customers, the power law has an exponent close to , that is d ∝ ρ. the authors found alignment in the analytical optimization and empirical distributions in the u.s. and south korea, confirming the / exponent for public services and the exponent for profit driven facilities. the simple power law at city scale reveals the equilibrium of empirical allocation of resources across cities with different population. however, distributing facilities at fine scale within cities, where the coverage area per facility is of few blocks (∼ km ), results in more heterogeneous settlements of population with different socio-economic characteristics. studies of accessibility within cities merit attention for science informed land use planning and the redistribution of public services after disasters and evacuations ( ) ( ) ( ) ( ) ( ) . forward-looking approaches for planning facilities in cities would also consider individuals preferences to facilities via mining mobility patterns. zhou et al. introduced a location-based social network dataset to derive the demand for different types of cultural resources, and identified the urban regions with lack of venues ( ) . while efforts have been devoted to address the optimal allocation problem in specific cities ( ) ( ) ( ) ( ) , systematic understanding of the optimal distribution of facilities is still lacking from the urban science perspective. to contribute in this direction, we propose a multi-city study that measures the accessibility of city blocks to different types of facilities through their road networks, and investigate the role of population distributions. while at large scale, travel cost can be substituted by the euclidean distance from residents to the facilities, road networks and geographic constraints play important roles for human mobility within cities ( ) ( ) ( ) ( ) . it has been well established that road network properties impact the daily journeys of residents ( ) ( ) ( ) , their urban form ( , ) and their accessibility ( , ) . as a complement to most studies devoted to travel costs of commuters, we analyze in this work the road network distance of individuals to the nearest amenity of various types, dividing the space in high resolution blocks of constant area of km . for each city and facility type, we optimally redistribute the existing facilities and compare the result with their empirical distribution. we observe that in the redistribution some blocks increase their accessibility and others decrease it. this implies that in order to make the best use of the existing facilities for a more equitable accessibility, some blocks would benefit whereas others would have facilities removed. at the city level, the gap between the empirical facility distribution and the optimal planning offers the opportunity to assess the planning quality of facilities in diverse cities. we also revisit the power law between facility and population densities, and observe that the two-thirds power law is not followed by the empirical cases, and it is observed in the optimal scenario only when the number of facilities is small compared to the total number of blocks in the city. we further investigate optimal distributions of facilities by modeling its average travel distance in different cities as a function of the number of facilities to assign. a model of this quantity is derived on both synthetic and real-world cities and fits different cities well with only two free parameters. furthermore, this gives us a universal function between the average travel distance and the number of facilities, controlled by the urban form derived from the population distribution. as an application case, we estimate the number of facilities required to achieve a given accessibility via the proposed function in real-world cities. we select three cities (boston, los angeles, new york city) in the u.s. and three cities (doha, dubai, riyadh) in the gulf cooperation countries (gcc) to study the empirical distribution of facilities. for each city we collect the population in blocks with a spatial resolution of arc-seconds ( km near the equator) from landscan ( ) , road networks with the open-streetmap ( ) , and facilities from the foursquare ( ) service application. these novel, rich, and publicly available datasets have proven value in transportation planning ( , , ) , land use studies ( , ) , and human activity modeling ( ) ( ) ( ) . the boundary of each city is drew along with the metroplex, encompassing both urban and rural regions. fig. depicts the road network, population density, and ten selected types of facilities (e.g., hospitals, schools) in new york city (nyc) and doha. the statistical information of six cities are summarized in table . for clarity, all variables and notations introduced in this work are summarized in note s . the distribution of all available facilities in foursquare data for the six cities are presented in fig. s . details of the data sets are described in the materials and methods and note s . it can be observed that doha and dubai have more facilities that are located in the highly populated areas, whereas boston has the majority of facilities located near the city center with fewer people reside. discrepancy in the distributions between population and facilities can also be observed in los angeles (la), nyc and riyadh. in these three cities, the population density peaks near the city center, but the facilities are distributed more uniformly across the city. it is noteworthy that, for calculating facility density and total number of facilities, we first merge the same type of facilities (e.g., hospitals) located in the same block as one facility. thus, the number of facilities thereafter refers to the number of blocks accommodating a given type of facility, denoted by n . we define n max as the total number of blocks in one city. furthermore, as nearly unpopulated blocks do not weight in the calculations of accessibility, we define n occ as the number of occupied blocks given by the blocks with population over a threshold. we set the threshold as in real-world cities, which is commonly used to distinguish between urban and rural regions. the ratio between the number of blocks occupied by facilities n and populated blocks n occ is denoted by d occ . table reports the d occ of the ten selected types of facilities in the six cities of study. as an example, d occ of hospital in boston equals . indicating that about % of populated blocks are occupied by hospitals. to quantify the accessibility of the population to facilities, previous work used the voronoi cell around each facility, as a proxy of the tendency of individuals to select the closest facility in euclidean distance ( , ) . however, within cities, the distance that people travel in the road networks is constrained by the infrastructure and the landscape. in this context, the routing distance is a better proxy of the accessibility from the place of residence to each amenity. fig. s c compares the distributions of routing distance of the actual and optimal locations of facilities vs. the euclidean distances, respectively. interestingly, our findings confirm that the optimal strategy based on euclidean distance achieves similar costs to the actual distribution of facilities, which is much less effective than the strategy that optimizes for routing distance. accessibility indicates the level of service of facilities to the residents. in network science, accessibility is defined as the ease of reaching points of interest within a given cost budget ( ) ( ) ( ) . how to allocate the facilities to maximize the overall accessibility in cities is one of the most essential concerns of facility planning. from this point of view, we redistribute the facilities by minimizing the total routing distance of population to their nearest facilities. in the following, we refer to this redistribution as the optimal scenario. likewise, the empirical distribution of facilities is referred to as the actual scenario. specifically, among the n max blocks of one city, we denote as facility-tagged the n blocks that are occupied by a given type of facility in the actual scenario and redistribute the same number of facilities in the optimal scenario. the shortest distance between any pair of two blocks is calculated using the dijkstras algorithm in the road network. the idea is to find a new set of n blocks and label them as facility-tagged such as it minimizes the total population-weighted travel distance from all n max blocks to the newly selected n blocks. this optimal allocation problem in networks is known as the p-median problem and here it is solved with an efficient algorithm proposed by resende and werneck ( ) (materials and methods). the difference of the travel distance between the actual and the optimal scenarios assesses the quality of the distribution, and therefore, of the accessibility in different cities. in each scenario, each residential block is associated with the facility that can be reached in the shortest routing distance. the block is linked to itself if it is occupied by a facility. it is important to note that we do not consider in the present study the capacity of facilities as a constraint, i.e., the number of people using the same facility is not limited. we group the set of blocks served by the same facility, and define them as a service community. considering hospitals as an example, we present in figs. a and b the service communities in boston in the actual and optimal scenarios, respectively. the color of each cluster depicts the total population p s j in the service in order to quantify the disparities between blocks in the level of service for a given type of facility, we compare the actual and optimal travel distances to facilities. we define a gain index of the ith block as: wherel i and l i are the shortest travel distances from the ith block to its nearest facility in the actual and optimal scenarios, respectively. a r i > identifies that the block is better served by the facility in the actual than the optimal scenario. residents living in these blocks benefit more from the distribution of facilities than they would in the scenario of social optimum. in table ). in the gcc cities, fire stations are the most equitably distributed facilities, while bars, hospitals, parks and pharmacies are distributed less equitably than others. the lorenz curves and the values of the gini coefficients per facility type are presented in fig. s b . the three cities in the u.s. are generally planned more equally than the gcc cities. thereafter, we compare the difference in accessibility across cities to various facility types. (l) to the ten selected types of amenities. the first row displays the facilities with higher densities in the u.s. cities: banks, pharmacies, schools, parks and bars. next comes hospitals and supermarkets, followed by concert halls, soccer fields and fire stations which have the lowest densities. as expected, the lower the density the longer the travel distance to them. note that the accessibility to parks, fire stations and bars have the largest differences between u.s. and gcc cities, mainly due to lower availability in the later. to compare the travel distance in different cities in the same order, we exhibit the scatterplots ofl and l versus d occ , the ratio between n and n occ , in figs. b and c, respectively. the discrepancy of actual travel distance box plot of the optimality index, r, by facility type. facility types are ranked by their average densities in the six cities in the descending order. among the facility types, fire station is the most optimally distributed and bank and school are the worst. in general, facility type with lower density is better located than dense facility type from the perspective of collective benefit maximization. l among the six cities is mainly caused by the difference in facility planning strategy and urban form. as expected, the optimal travel distance l displays a more uniform tendency thanl, revealing the potential of modeling l with the number of facilities n . an interesting measure is the improvement of overall accessibility if the locations of facilities are optimally redistributed at city scale. to that end, we define the optimality index r for a given type of facility at city level as the ratio between the average travel distance to the nearest facilities in the optimal and actual scenarios, where p i is the population in the ith block. r ranges from to , with indicating the facilities are optimally distributed in reality. in note s and fig. s c , we discuss the change of r with n/n max by introducing two extreme planning strategies, random and population-weighted assignments, described in note s . we observe that r score of actual planning is mostly between the two extreme strategies, except riyadh, in which r is even lower than random assignment. this suggests the imbalance between facility locations and service delivery in riyadh ( ) . besides, we observe the r score of actual planning is the highest when n/n max is the smallest for cities, except la and nyc. for the two extreme strategies, we observe r is u-shaped as a previous work has related the facility density to population density as a power function both in the actual and optimal scenarios ( ) at the national scale. here, through introducing the specifically, d s j = /a s j , and ρ s j =p s j /a s j , where a s j is approximated by the product of the number of blocks n s j and the average block area in the city, that is a s j =n s jā . taking hospitals as an example, their densities versus the population densities of the service communities in the actual scenario over the six cities are illustrated in fig. a . the full lines represent the fitted power law functions with least squares method and with communities with more than residents. cities have different exponents and the r scores of the fitting are less than . in most cases. these results show that, despite the / power law was found for public facilities at countyresolution ( ), we do not find a uniform law between facility and population densities at finer resolutions i.e., intra-city community level. once facilities are optimally redistributed in the city, the service communities are reorganized accordingly. the fitted power laws between the distribution of hospitals and population in optimal scenario of the six cities are shown in fig. b . the fitted exponents are closer to / and have larger r , and the % confidence intervals are narrower than those in fig. a , depicting the actual scenario. the exponents for the ten selected types of facilities in the actual and optimal scenarios are reported in table s . as expected, cities have different exponents for both actual and optimal scenarios. in all cases, we observe that the optimal exponents deviate from the analytical / previously reported when the facilities are optimally distributed by euclidean distance at national case ( ) . sources of difference are both the constraints introduced by the road networks and the higher density of facilities to be distributed. for a comprehensive understanding of the existence of the power laws, we optimally allocate varying number of facilities n in our six cities of study and in synthetic cities. in figs. c and d, we relate the β to d occ , the ratio of n to n occ , and observe / when d occ < . ( . ) for the real-world (synthetic) cities. we simulate controlled scenarios via four synthetic or toy cities of size × , with population distributions depicted in fig. a . note that the population threshold is set as in toy cities to count n occ , and the total population is fixed as half million, which is about / of the studied cities. we find the curves of diverse cities collapse into a single one, indicating the difference in the change of β across cities is mainly caused by different n occ . interestingly, in the toy cities, we notice that the change of β is not monotonous. it stays around / when d occ is below . . subsequently, β decreases with d occ as more facilities are assigned to the low density regions and then increases as facilities start to refill the high density regions. after all high density blocks are assigned with facilities, β starts to drop to zero, implying all blocks are filled with facilities. the same fluctuation of β is not clearly observed in real-world cities because the large and low density regions are not segregated like in the synthetic cities. in summary, in the optimal scenario, the / power law can be found for a limited number of facilities, but tends to disappear for larger values of n . in fig. b we see that d occ is the most determinant factor to decrease the average distancel to a facility independent of its type and city. interestingly, in fig. c we observe that these de- for an estimate of the optimal travel distance l in each city, we first assume the in-block travel distance is constant l min = . km, and the average travel distance within a service community approximates to g s j a s j,occ , where g s j denotes the geometric factor in the community; a s j,occ denotes the area of the occupied blocks ( ) . then l is expressed as the sum of two terms, the first for the population in the n blocks with facilities and the second for the population in the n max −n blocks without facilities: where p is the total population in the city,p s j denotes the population in the service community of the jth facility after removing the block where the jth facility is located, that isp s j =p s j −p j . we find that a s j,occ follows power law relation to the total area in community a s j in most cities, that is a s j,occ ∝ (a s j ) γ ( fig. s a ). we assume that g s j is constant in each city, written as g city , and a s j ≈ a s =ā · n max /n withā denoting the average block area in the city. then we can rewrite eq. as where p(n ) denotes the share of population in blocks with facilities; a and λ are both constant. more details of this derivation can be found in note s . . we further study how the share of population in blocks without facilities is related to the number of facilities n , and find − p(n ) ≈ e −αn when n n occ (see details in fig. s b , notes s . and s . ). thereby, we could model l as where the number of facilities n is the main variable that determines l. while α controls the relation between p(n ) and n ; a and λ are two free parameters to calibrate. the model of l(n ) summarizes the fact that to model l the only two essential ingredients are the number of facilities to allocate n and the distribution of population in space. next, we numerically assign the optimal distribution of facilities given varying number of facilities for both toy and real-world cities. we present the average travel distance l versus the number of facilities n in the toy and real-world cities in log-log plots in figs for seeking a universal function to approach the simulated l in diverse cities, we use λ in eq. as a constant, fixing its average empirical valueλ = . in the real-world cities. combining the observation that n max is inversely proportional to α and a ≈ g city a λ n λ max (note s . ), we can expect that a ∝ α −λ . figure s c confirms this, showing that a = . α −λ . we can rewrite eq. as follows: this function with only one free parameter α suggests that we are able to rescale n with α to collapse the curves of l in all cities into one, as shown in fig. f that depicts eq. as solid line. the same rescaling of n in toy cities is presented in fig. e , where the collapse is not as good as in the real cities due to the divergent values of λ of toy cities in table s . next, we go beyond the average distance l and plot the distribution of travel distances when keeping αn fixed (figs. s f and s g). in all cases the travel distance follows a gamma distribution. this universality suggests that: (i) given a certain αn , all real-world cities can reach comparable accessibility; (ii) the overall accessibility in the optimal scenario not only depends on the availability of the resources but also the settlement of population, independently from the road network and total area of the city. empirically, the decay of population share in blocks without facilities α depends on the population distribution in space. taking into account that unpopulated blocks are not ideal when optimizing accessibility, n occ is a better variable to express α. a good agreement α= . /n occ (r = . ) over the real-world cities is shown in fig. g , suggesting that α can be estimated by n occ . given that α= . /n occ and the universal relation of l(αn ), we can explain the collapses found in figs. c, c and d. as a concrete application of this universal model for optimal distance of facilities, in eq. , we can plan for facilities by, for example, extracting how many facilities are needed for varying levels of accessibility to a given type of service. in this context, the number of facilities n can be estimated with the inverse function of eq. . as the second term in eq. dominates the l for a limited n , we simply invert the second term to estimate n , given by n (l; α) = planning. this became ever more evident when distributing the healthcare system resources during the outbreak of a pandemic, such as the covid- in . population density the population with a spatial resolution of arc-seconds (approximately km near the equator) of each city was obtained from the landscan ( ) s . we select types of facilities to inspect their actual and optimal planning and they are given in the legend of fig. . after merging facilities of the same type located in the same block, the occupancy of each type of facility, n/n occ , are presented in table . the u.s. cities generally have more dense facilities than the gcc cities. road networks we extract the road networks from openstreetmap ( ) . the road network is represented as a directed graph, in which edges indicate road segments and nodes indicate intersections. each edge is associated with a weight representing its length. the travel distance between two blocks is computed by finding the shortest path between two randomly selected nodes in these blocks using dijkstra algorithm ( ) . finding the optimal locations of facilities to minimize the total travel cost is essentially an optimal placement problem in network theory, which is np-hard and known as p-median problem. the problem in this work is formalized as follows: "given a set of blocks n max in a city, a set of residential blocks x ∈ n max are with population, and each block in n max can only accommodate one facility. the goal is to open n facilities in n max so as to minimize the sum of population-weighted travel distances from each residential block to its nearest open facility." ( ) for simplicity, the p-median problem is written as a linear programming problem. where i and j are indices of the blocks; x i,j = means that people living in block i are assigned to their nearest facility in block j, and i=j signifies that there is a facility located in residential block i; y j = if there is a facility in block j, else y j = ; n is the number of facilities to assign and we assume that one block can only accommodate one facility of the same type; c i,j is the travel cost from block i to block j, which equals to the total routing distance of all population residing in block i. in this work, we solve the p-median problem with a fast algorithm based on swap-based local search procedure implemented by resende and werneck ( ) . we adopt the uci proposed by pereira et al. to measure the centrality of the population distribution in cities ( ) . uci is the product of two components, the location coefficient (lc) and the proximity index (pi). the former is introduced to measure the inhomogeneity of population distribution in space. the latter is introduced to measure the difference between the current distribution and the most decentralized scenario. the calculation of lc and pi are as follows. where v = s × d × s. s is a vector of population fraction in block i, s i =p i /p , signifying the share of population in block i (p i ) of the total population of the city (p ); d is the distance matrix between blocks. v max is calculated by assuming the total population are uniformly settling on the boundary of the city, which indicates an extreme sprawl. uci ranges from to . large uci values indicate more centralized population distributions. note s : list of variables and notations for the accessibility analysis. note s : data description. note s : on the optimality index. note s : derivation of the average optimal travel distance. table s . best fitted exponent of the power law for the actual and optimal distribution of facilities. table s . fitted parameters of the toy cities and the real cities. references ( ) ( ) ( ) ( ) ( ) . modelling urban growth patterns urban characteristics attributable to density-driven tie formation growth, innovation, scaling, and the pace of life in cities a unified theory of urban living cities, productivity, and quality of life the origins of scaling in cities a global map of travel time to cities to assess inequalities in accessibility in the area and population of cities: new insights from a different perspective on cities city size, network structure and traffic congestion professional diversity and the productivity of cities the scaling of human interactions with city size heterogeneity and scale of sustainable development in cities simple spatial scaling rules behind complex cities power laws, pareto distributions and zipf's law from global scaling to the dynamics of individual cities the statistical physics of cities optimal design of spatial distribution networks scaling laws between 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cities: from mobility patterns to scaling from mobile phone data to the spatial structure of cities measuring the impact of economic well being in commuting networks-a case study of bogota, colombia emergence of hierarchy in cost-driven growth of spatial networks encapsulating urban traffic rhythms into road networks understanding congested travel in urban areas elementary processes governing the evolution of road networks a typology of street patterns modeling the polycentric transition of cities openstreetmap the path most traveled: travel demand estimation using big data resources collective benefits in traffic during mega events via the use of information technologies mining urban deprivation from foursquare: implicit crowdsourcing of city land use using foursquare place data for estimating building block use communicating through location: the understood meaning of the foursquare check-in semantic enrichment of movement behavior with foursquarea visual analytics approach unraveling environmental justice in ambient pm . exposure in beijing: a big data approach an accessibility-maximization approach to road network planning spatial networks network structure and city size a fast swap-based local search procedure for location problems geographic distribution of public health hospitals in riyadh, saudi arabia urban centrality: a simple index a note on two problems in connexion with graphs theory in practice fractal cities: a geometry of form and function location and land use urbanization and urban problems cities and housing urban population densities this work was supported by the qcri-csail, the berkeley deepdrive (bdd) and the university of california institute of transportation studies (uc its) research grants. yx, leo, sa and mcg conceived the research and designed the analyses. yx and sa collected the data. yx and leo performed the analyses. mcg and yx wrote the paper. mcg supervised the research. the authors declare that they have no competing interests. all data needed to evaluate the conclusions in the paper are present in the paper and/or the supplementary materials. additional data related to this paper may be requested from the authors. key: cord- -w yri g authors: kubo, tomoko title: divided tokyo: housing policy, the ideology of homeownership, and the growing contrast between the city center and the suburbs date: - - journal: divided tokyo doi: . / - - - - _ sha: doc_id: cord_uid: w yri g this chapter examines the generation of tokyo’s division over time by focusing on the changes in national and municipal policies on urban planning, land use, and housing, as well as the outcomes of these long-term trajectories since the s onward. by comparing with the western urban discourse, we clarify the process of how tokyo became divided in terms of residential conditions. the national government focused on the growth of major metropolitan areas, stimulating suburban development and homeownership in the suburbs from the s to the s. however, after the late s, the target shifted from the suburbs to the city centers. alongside global competition among cities, the long-term recession of the japanese economy, and social changes, continuous investment to grow central tokyo has increased in importance. in contrast, suburban neighborhoods are facing challenges related to an aging population and an increase in housing vacancies. although government intervention is necessary, there are limited possibilities for the outer suburbs to revitalize and re-grow. the sharp contrast between the growth in city centers and the shrinking suburbs, and specifically the divided tokyo, will become more obvious in the next decade. labor market, shifting from a manufacturing orientation toward domination by financial and service industries in the city center (fainstein et al. ) . as global cities have become the sites of production and coordination (sassen ) , their spatial patterns have also been transformed and are now characterized by more division, inequality, polarization, and fragmentation (sassen ; scott ) . in addition, globalization has accelerated competition among cities, and many municipal governments have moved toward entrepreneurialism (gonzalez ) . this move has been followed by real estate developers building multi-functional condominiums in city centers, targeting single women, high-income couples, urban elites, and the creative classes (florida ; kern ; koizumi et al. ; kubo and yui a; scott ) . as a global city, tokyo has experienced spatial restructuring alongside the shift to "the third wave of capitalism," characterized by the growth of city centers consequent to labor market changes and project-oriented urban entrepreneurialism (gonzalez ; jacobs ; sassen ; scott ) . this shift followed the factory production of the nineteenth century and the mass production and emergence of metropolitan urban forms in the twentieth century (scott ) . globalization has transformed the role of city regions and urban governance, promoting spatial restructuring on many scales such as within individual metropolitan areas and city centers, as well as in national and international urban networks. the fact of inter-urban competition and urban entrepreneurialism has opened up the urban space of the advanced capitalist countries to all kinds of new patterns of development, even when the net effect has been the serial reproduction of science parks, gentrification, world trading centers, cultural and entertainment centers, large-scale interior shopping malls with postmodern accouterments, and the like. the emphasis on the production of a good local business climate has emphasised the importance of the locality as a site of regulation of infrastructural position, labour relations, environmental controls, and even tax policy vis-à-vis international capital. (harvey , p. ) to succeed in the face of global and domestic competition, the tokyo metropolitan government adopted a policy of entrepreneurialism (promoting the "new patterns of development" mentioned in the above quote) beginning in the first decade of the twenty-first century (boland ; gonzalez ; jacobs ) . this policy shift not only increased the number of urban condominium developments (kubo and yui a ) and encouraged population recovery (miyazawa and abe ; yabe ) but also intensified the growth of inequality within the tokyo metropolitan area (hirayama ; jacobs ) . urban growth in central tokyo and shrinkage in the suburbs became obvious (kubo ) , and the emergence of "hot and cold spots" divided the city, even in central tokyo, because entrepreneurial urban policies exacerbated the unevenness of urban development (smith ; hirayama ) . the neo-liberal national policies that stimulated urban renewal through the deregulation of urban planning, building standards, and the housing market (e.g., the urban renaissance special measure law of ) strongly supported the re-growth of central tokyo from the beginning of the twenty-first century onward. for instance, the deregulation of the floor-space ratio enabled super high-rise buildings in commercial and industrial areas in central tokyo, offering bonus floor space to projects providing vacant public spaces that could serve as evacuation sites in natural disasters or other emergencies (kubo ; abe et al. ) . new-build gentrification, ranging from the development of vacant commercial, industrial, or reclaimed land to super high-rise buildings, has transformed central tokyo's landscape since the beginning of the twenty-first century (lutzeler ) . additionally, many areas surrounding train stations and airports offered large tracts of vacant land that was well-suited to huge urban renewal projects. with the facilitating influence of municipal policies, these areas were targeted for new urban development in tokyo and other large japanese cities. to understand the recent urban spatial restructuring in the context of globalization, the trajectories of urban housing policies and urban governance as well as their outcomes (spatial structures) must be examined. in this chapter, we examine how urban and housing policies have affected urban spatial structures, caused a divide between the city center and the suburbs, and transformed the urban lifestyle in the tokyo metropolitan area. starting with a chronicle of urban policies in japan, we review the post-war housing policies that stimulated suburban homeownership and the horizontal expansion of the tokyo metropolitan area. then, the recent spatial restructuring accompanying the emergence of urban governance under globalization is examined. we focus on the housing market from the beginning of the twenty-first century onward and on aviation governance. through globalization, transit hubs such as airports have gradually become centers of urban development projects, known as transit-oriented development. focusing on aviation governance as a case study helps to clarify the spatial restructuring that has occurred in recent decades in the tokyo metropolitan area. the discussion is positioned within the context of the transformation of the spatial structure of the tokyo metropolitan area in modern times. most differences between housing patterns in japan and those in western cities are a result of the unique family system and household ownership trends in the late nineteenth and early twentieth centuries in japan. after the meiji restoration in the s, which opened japan to new influences and industrial progress, a civil law was passed establishing, that is, ie-seido (the family institution). japan had had a long history as a feudal society in which traditional lords and families owned most of the land and houses. however, this new law passed in the late meiji era categorized people by family unit or parentage and allowed them to select their jobs and place of residence. the law also allowed people to own real estates, such as houses and land if desired, although the family patriarch made decisions regarding the latter. therefore, the history of land and house ownership by individuals in japan is relatively short. even as recently as , the homeownership rate was only % in major japanese cities (ronald ) . importantly, family members did not share equally in the family's property. patriarchs held majority control and transferred their properties to their eldest sons, who traditionally continued to look after their parents in the family home. as a result, the other sons and the daughters left the original family and formed new families through marriage. this meant that the younger sons (i.e., the male heads of the new families) needed to find jobs in other areas, which led to residential mobility from rural areas to the growing, densely populated urban zones. thus, the housing custom based on the patriarchal family institution, which was supported by the ideology that homeownership should be dominated by men, was legally codified in japan (ronald ). because few women had paying jobs, they lived with their parents until marriage. a few exceptions were found in metropolitan centers such as tokyo and osaka. for example, in tokyo, rental apartments for working women were built by dojunkai, a government institution for housing development established for the purpose of urban reconstruction after the great kanto earthquake of (kageyama ). in general, however, there were few possibilities for women to own houses or to overcome the patrimony that was dominant during this period. although the family institution law was abolished in , soon after the second world war, the old patriarchal and multi-generational housing customs remained until recently in many rural areas, and also influenced household composition in the growing urban areas. for example, even in the s, more than % of couples who had been married for more than years lived with one of the spouses' parents (kato ) . although people tended to move to metropolitan centers in the booming postwar period in search of jobs, they hoped to eventually buy a detached house. thus, suburban nuclear families gradually became a common family form in metropolitan areas. the suburbanization of modern japanese cities started at the beginning of the twentieth century, when western urban planning methods such as the development of "garden cities" were adopted. in , volunteers from the regional division of the ministry of home affairs of japan published a book entitled "den'en toshi" which literally translates as "garden city." as the depleted condition of land in rural areas had become a serious issue, the japanese government developed energetic campaigns to improve rural infrastructure. connecting the conveniences of urban areas with rural amenities as garden city developments were intended to do was considered an attractive method for improving the rural environment. little attention was paid to the notion that these areas should be self-sufficient or to the conception that workplaces are to be located near residential areas. the main concern was how to create a good residential environment for urban and rural settlements (suzuki ) . in japan, the garden city movement was started in osaka in by kobayashi ichizo, a powerful entrepreneur who founded the hankyu toho group. the main developers were private railway companies aiming to attract potential residents along their rail lines. for example, in , kansai tochi inc. launched a plan to build ohmino den'en toshi in sakai city, osaka. the plan focused on a very large area (approximately . ha) near the kita-noda station of the nankai electric railway koya line, and it clearly displayed the typical landscape of a garden city, with radiating roads extending from a central roundabout. although the planners had visited letchworth garden city and welwyn garden city in the united kingdom to study them, they were mostly interested in these cities' landscapes and in determining how to provide better, well-planned residential environments outside large cities. these interests were prioritized over adopting the maintenance and management systems, theory, or concepts such as providing rental housing for the working classaspects that were central to the garden city idea (kikuchi ) . the movement then spread to tokyo, as manifested in the epoch-making project conceptualized in the "senzoku, tamagawa plan," which is now considered a symbol of the luxurious residential district of den'en chofu. the plan was implemented in the senzoku, o'okayama, and tamagawa areas of tokyo suburbs by den'en toshi company ltd. ("garden city company"), a direct predecessor of the tokyu railroad company and its related businesses. it was built by shibusawa hideo, the son of shibusawa eiichi, a powerful entrepreneur in the late nineteenth century who consulted for the company. the company obtained - ha of land on which to build their envisioned utopia. the senzoku area was first to be developed in , followed by tamagawa-dai and o'okayama beginning in . particularly in tamagawa-dai (now called den'en chofu), the design of the landscape was strongly influenced by sir ebenezer howard's garden city concept, comprising a concentric structure with radial roads extending from a main station. similar developments emerged in the nagoya metropolitan area, where municipal planners adopted the idea of "san-rin toshi" (literally meaning "forest city"), constructing hillside developments in the yagoto area (hotta ). these planners paid great attention to retaining the natural landscape and the inclination of the hillside when building roads and in other types of land use. the great kanto earthquake of destroyed tokyo, stimulating modern urban redevelopment projects led by goto shinpei (edgington ) and fueling the relocation of major urban industries and housing developments from central tokyo to the west, where the stable musashino terrace had sustained minimal damage. in contrast, a large part of central tokyo had been destroyed in the earthquake and the fire that followed because its reclaimed lowland was filled with high-density wooden apartments. in the s and s, undeveloped open land on the musashino terrace welcomed large housing developments, defense industry construction (e.g., nakajima aircraft industry ltd.'s musashino factory), and company housing for employees. today, these modern suburban development areas are considered a part of the center of the tokyo metropolitan area. post-war suburban residential developments have expanded beyond prefectural boundaries alongside the popularization of a caroriented lifestyle. these changes have been supported by national policies aimed at stimulating suburban/urban development, for example, by constructing highways and reclaiming land for large-scale developments. this is discussed in depth in the following sections. many post-war spatial, urban, and housing regulations established in the s developed the fundamental urban systems and institutional structures of japan (abe et al. ) . for instance, a spatial plan based on the comprehensive national land development act of determined development measures in japan. this act was characterized by a hierarchical framework comprising national, regional, and prefectural levels of administration. in the s, the most urgent issue that housing policies had to address was the housing shortage after the war. the national government established major housing policies for this purpose. for example, the japanese housing finance agency was set up in to finance homeownership by high-income families. following this, the japan housing corporation began developing housing complexes in and later developed huge housing estates in the suburbs to supply affordable housing for middle-income people. the government also built social housing for less affluent families (japan federation of housing organizations ; kageyama ). these post-war policies were regularly modified, eventually shifting from welfare state policies aiming for equal growth in industry, urban infrastructure, and quality of life throughout japan to neo-liberal policies that stimulated inequality between core metropolitan centers and the surrounding regions (forrest and hirayama ). the result was that tokyo emerged as the clear winner, followed by osaka and nagoya. this led to the creation of the tokaido megalopolis and turned other areas into shrinking regions (abe et al. ) . one example is the change in procedures regarding social housing, which from the to the s was preferred by young married couples who wanted to save money to buy their own homes in the near future. they tended to spend the years when their income was relatively low dreaming of climbing the housing ladder leading to homeownership. later, because the income restriction became stricter over time, social housing came to accommodate mainly low-income households, single-parent families, and single older adults (hayakawa ; yui yui , . the comprehensive national development plan of stimulated industrialization throughout japan and encouraged the formation of new industries in middle-and small-sized cities. to overcome the problems in cities related to rapid urbanization in major metropolitan areas, many city governments developed their own urban zoning plans, delineating their urban areas into two categories: ( ) urbanization promotion areas that stimulated urban and economic development with strict zoning plans; and ( ) urbanization control zones that strictly controlled urban development to maintain a pleasant rural and agricultural environment (the classification was based on the city planning act of ). the comprehensive national development plan of stimulated economic and urban growth in seven major metropolitan areas (tokyo, osaka, nagoya, sapporo, sendai, hiroshima, and fukuoka) by expanding high-speed transportation systems nationwide. these major cities strengthened their management function, concentrating on large enterprises, manufacturing, and transportation systems. along with the economic growth of major metropolitan areas, suburban neighborhoods were developed by the public and private sectors in the and s, accommodating the growing young middle-income people and providing them with a pleasant residential environment. planning concepts such as the garden city or the neighborhood unit (perry ) were adopted from the west. after the excessive horizontal expansion of major metropolitan areas, the comprehensive national development plan aimed at decentralization, and new business districts in the suburbs were developed through collaboration between municipal and national governments in major metropolitan areas. yokohama city's minato mirai , chiba city's makuhari new city (see chap. ), and saitama city's omiya sonic city represent public suburban development in the tokyo metropolitan area (sato (sato , sato and arai a, b) . however, the collapse of the japanese bubble economy rapidly drained energy from middle-and small-sized cities after the s. consequently, the closure of central shopping streets and the aging of shop owners accelerated the process of decline. gradually, an empty space expanded in many japanese cities (shinohara ) . in major metropolitan areas, suburbanization led to population loss in the city centers. to deal with this problem, the national government passed the urban renaissance special measure law in , a neo-liberal spatial policy promoting deregulation in urban planning, land use, and housing supply. through city center redevelopment, governments expected to overcome the long-term economic recession and stimulate rebuilding projects to increase the number of disaster-proof buildings (abe et al. ). this policy strengthened the power of central tokyo and facilitated recovery in terms of both population and economic activity in the first decade of the twentyfirst century (koizumi et al. ; miyazawa and abe ; yabe ). by the next decade, the spatial divide between the growth in the city centers and the lower levels of investment and greater aging in the suburbs became inevitable (hirayama ; kubo ; kubo et al. ; yui et al. yui et al. , ; see also chaps. , , and ). since the s, the national and municipal governments in japan have focused on urban development and on enlivening major metropolitan areas. during the long-term economic recession beginning in the s, central tokyo was targeted for economic development to stimulate the japanese economy. today, city centers can accommodate their workers in newly built condominiums, resulting in the out-migration of the younger generations from the outer suburbs. the complementary relationship between city centers offering job opportunities and the suburbs providing accommodation for these workers has gradually dissolved. in the next section, we focus on changes in the residential preferences of the younger generations. in japan, the ideology of homeownership became increasingly valued during the period of rapid economic growth beginning after the s (ronald ) . however, the high costs of land and housing meant that there was a lack of affordable housing options in metropolitan centers, which led to a major suburban boom from the to the s (tani ) , mostly concerning detached houses (hasegawa ; matsubara ) . the boom was fueled by migrants from japan's rural areas who relocated to major growing cities such as tokyo in search of jobs (tani ) . consequently, the rate of homeownership had reached % at the beginning of the s (hirayama and ronald ) . soaring central city land prices in the and land-oriented property ownership, the so-called "myth of real property," strengthened the new preference for detached houses in the suburbs (van vliet and hirayama ). many people climbed the housing ladder, seeking to attain social presence, stability, and security (hirayama b) . thus, suburban housing developments expanded horizontally beyond prefectural boundaries from the to the s. for instance, tokyo's suburbs expanded as far as km from central tokyo, requiring a two-hour daily commute. rental houses were built mainly for single people and students by private developers and for low-income families by the public sector. however, the inferior building materials and facilities in these housing units compared with owner-occupied detached houses highlighted the clear inequality between housing types. this resulted in a range of housing classes, spearheaded by owner-occupied units, followed by rental housing and public housing units (hayakawa ) . this residential segregation on the basis of socio-economic status and housing class has strengthened over time. the long-term economic stagnation beginning in the s stimulated neo-liberalism in japanese society, where the housing supply and mortgages depended on private companies and self-responsibility was emphasized (hirayama a) . the relationship between family, welfare, and housing in society has transformed dramatically over time (ronald and lennarts ) . major changes have occurred in housing patterns in large japanese cities. the preference for suburban detached houses has rapidly faded, resulting in more condensed city center living because of greater interest in central housing (see also chaps. and ). this can be attributed to the following factors (kubo and yui b) . first, japan has experienced relative economic stagnation since the collapse of the bubble economy, and the labor market has been restructured, including the outsourcing of many industrial jobs to lower-wage countries and growth in the service, information, highly specialized financial, and creative sectors in the domestic market. this is similar to the experience in many global cities since the s (sassen ) . this stagnation has led to the neglect of old industrial sites, the selling of company housing to allow companies to survive the recession, and the expanding unused reclaimed land along the river and bay areas in cities, which increased the availability of land for redevelopment. furthermore, an increase in white-collar and service/information jobs in central areas has led to an increased new housing demand nearby. second, excessive horizontal expansion of the suburbs has led to increased concerns regarding long commutes. during the long-term recession, many companies reduced their staff sizes, and the employees they retained have had to work longer hours to complete the same volume of work. reducing commuting time thus became an important strategy for dual-income couples to create sufficient time for housekeeping and childcare along with their full-time jobs (koizumi et al. ) . city center living was thus seen as an attractive option because it reduced the time necessary to commute to work. third, the rapid aging of the japanese population and the declining fertility rate have both affected residential preferences. young women have gained more lifestyle independence and occupational freedom, especially in the service sectors. in , only . % of women were unmarried by age - years, but this had increased to . % by . the number of single women with significant purchasing power has increased in large cities (kubo and yui b) . in addition, more women keep their jobs after marriage, and living in the city center rather than in the suburbs provides them with more opportunities for white-collar, service, and information jobs (koizumi et al. ) . since the second decade of the twenty-first century, the japanese population has been declining, as have functional urban areas in the country (ezaki ) . furthermore, the suburbs have not been attracting new investment (hirayama ) , rendering them less popular as residential areas. suburban areas began to face challenges caused by the aging of their residents and an increase in vacant housing (kubo and yui ; naganuma et al. ; yui et al. yui et al. , . both the aging of the remaining residents and the out-migration of the younger generations increased population aging in many neighborhoods (kubo et al. ; nordvik and gulbrandsen ; yui ) . according to the statistics bureau of japan's housing and land survey ( ), more than % of owner-occupied houses were either newly built or newly purchased, and a strong preference for newly built houses dominated the owner-occupied market. in contrast, only . % of owner-occupied houses were previously owned by others. the fragile existing housing market and dramatic decline in mobility after homeownership in japan have increased the percentage of older adults in the population of homeowners. population aging and an increase in vacant housing have led to shrinkage of the suburbs, which were developed in the s and s yui et al. yui et al. , . a declining level of public investment and limited access to the financial resources necessary to revitalize suburban neighborhoods have fueled this shrinking process. the question is whether suburban stagnation is merely a stage of the neighborhood lifecycle or a longer-term shift. private developers generally tend to avoid new developments in stagnant areas because of the high level of risk involved (ley ) . here, government mortgages, subsidies, and other forms of support such as public-private cooperation and tax incentives play an important role in minimizing the perceived risk (ley ; smith ) . however, the japanese government has thus far not intervened in suburban development (see also chaps. and ). in contrast, the growth of central tokyo is becoming increasingly important in the context of competition among global cities. tokyo will host the olympic and paralympic games in (tokyo will be postponed until due to the expansion of covid- ), encouraging more public investment in the economic development of the city's central area (gonzalez ) . this investment will exacerbate the urban divide between growing central tokyo and the shrinking suburbs. city center renewal is explained in more detail in the next section. from to , the number of condominium housing units sold increased from , to , in central tokyo (fig. . ) . figure . shows the rapid growth of condominium developments and the decline in the average price of condominiums in tokyo during this period. in these years, many potential homeowners were the children of post-war baby boomers and had grown up in metropolitan suburbs. because their parents had owned real estate in major metropolitan areas, this group of potential homeowners tended to have preferences regarding lifestyle and the family-housing the neighborhood lifecycle is one of the classical urban ecology models of american cities. neighborhoods are transformed over time through the following stages (hoover and vernon ): ( ) development; ( ) expansion through intervention and the transition of specific neighborhood characteristics in terms of housing and residents into surrounding areas; ( ) stagnation and shrinkage of neighborhoods as a result of the deterioration of buildings and filtering-down effects, inadequate maintenance, and insufficient investment caused by a lack of access to financial resources; and ( ) renewal involving demolition and/or redevelopment via either public or private investments. the ability of residents or communities to access financial resources at various points in this cycle has led to the decline and (re)growth of neighborhoods in the united states, which has also been strongly affected by federal and state policies (metzger ) . relationship that differed from those of their parents. they preferred living in condominiums in the city center over moving to the suburbs to purchase a home. the growth in the number of condominiums has facilitated this new lifestyle trend. condominiums attract single women in their s and s with significant purchasing power who previously lacked alternatives that would satisfy their need for high-quality housing (see also chap. ). the upsurge in the number of condominiums in central tokyo was strongly affected by neo-liberal housing policies introduced in the s, such as deregulation of urban developments, the mortgage market, and building standards, which encouraged urban development projects. kubo ( ) has noted that this deregulation of the mortgage market strengthened the diversification of long-term housing loans by private banks and public institutions, on which most first-time homeowners depend. for example, before , the japan housing finance agency (formerly the government housing loan corporation) provided long-term, low-interest housing loans called "flat ," which had an average annual interest rate of less than . %. other private finance agencies providing long-term housing loans for middle-class homeowners followed the interest rates set by the japan housing finance agency. beginning in , the japan housing finance agency's interest rate gradually rose, but other private finance agencies continued to provide long-term housing loans at lower rates. thus, potential homeowners were easily able to purchase a home by selecting one of these long-term, low-interest loans (kubo ) . another change was that the deregulation of building standards and urban development stimulated the construction of super high-rise buildings. since the s, the japanese government has promoted rebuilding and providing parks and wide roads for disaster prevention, and deregulating the floor-space ratio was the simplest way to achieve this. the total design system of , for example, specified that a floor-space ratio bonus would be provided for development plans involving a certain amount of vacant land. after , the japanese government accelerated these deregulation processes, including the relaxation of floor-space ratios, enabling the construction of super high-rise buildings in central tokyo. currently, developers can apply for floor-space ratio bonuses if their projects include vacant public spaces that can serve as evacuation sites during emergencies. as mentioned above, the population in central tokyo declined through the early s. however, the deregulation of the floor-space ratio facilitated the construction of super high-rise residential buildings, enabling potential homeowners to purchase condominiums and increasing the popularity of living in the city center. as a result, population recovery was seen in central tokyo from the beginning of the twenty-first century. according to japan's population census (statistics bureau of japan ), . % of the country's inhabitants lived in central tokyo in . from to , japan's population dropped by , people (a decline of . %). conversely, central tokyo gained , people (an increase of . %) during the same period. this clearly contrasts with population trends in the largest metropolitan centers in other parts of japan. more importantly, population growth in central tokyo is supported by the new and growing "going solo" lifestyle (klinenberg ), which is not generally accepted in other parts of japan. as self-responsibility and the privatization of property began to highlight the advantage of city living, single women emerged as a new class of urban homeowners in tokyo, and the situation in central tokyo came to mirror the increasing popularity of women living alone in metropolitan areas in many other parts of the world. in canada, for example, kern ( ) found that women's condominium ownership grew under neo-liberal policies in central toronto. in the following sections, we examine neo-liberal urban policies and transitoriented development, which emerged in the first decade of the twenty-first century. the transformation of aviation governance in the tokyo metropolitan area illustrates the increasing importance of urban governance (harvey ) in ensuring tokyo's competitive advantage. a strategy promoting transit-oriented development in the first decade of the twenty-first century changed the role of airports in the tokyo metropolitan area. the tokyo metropolitan government ( ) has cited improving the transportation system and urban infrastructure as one of eight strategies aimed at increasing tokyo's competitiveness. the challenge of hosting the olympic and paralympic games in and the rise of east asian cities in the global economy pushed the national and municipal governments in a neo-liberal and entrepreneurial direction after the first decade of the twenty-first century (gonzalez ) . the municipal government initiated transit-oriented development to enable better access within tokyo and to increase passenger traffic. reflecting municipal policies, private transportation companies, such as the east japan railway company, tokyo metro, and japan airport terminal co. ltd., launched several renewal, improvement, and new development projects on their properties (see, e.g., east japan railway company ). regarding the domestic urban political context, here, we focus on the processes of deregulation and privatization of airport logistics and related businesses in japan. traditionally, after the s, the national government owned and operated japanese airports, the public sector dominated the logistics of the airport business, and the private sector managed related facilities at airports. this unique system resulted in higher landing fees, especially at haneda airport, and inefficiency in airport operations (the council of the growth strategy of mlit ). along with the long-term economic recession in japan since the s, neo-liberal policy deregulating and privatizing public-owned services has been the key in maintaining tokyo's competitiveness. as the population in most japanese cities started to shrink and economic conditions worsened after the first decade of the twenty-first century (kubo and mashita ) , maintaining tokyo's strength was expected to contribute to the recovery of the japanese economy. against this backdrop, the council of the growth strategy of the ministry of land, infrastructure, transport and tourism (mlit) launched "the growth strategy of mlit ( )," which included six strategies designed to improve japanese airport management. these were: ( ) internationalization of japanese airports by offering better access to other asian countries; ( ) updating the infrastructure of haneda and narita airports to increase tokyo's competitiveness; ( ) introducing private skills and financial resources to ensure more efficient airport management and operation; ( ) achieving a better debt-income ratio at kansai airport; ( ) improving the essential domestic airport network; and ( ) accepting low-cost carriers to maximize benefits for passengers (the council of the growth strategy of mlit ). following the publication of this report, the management rights for airport logistics and airport-related facilities were awarded to private companies. as the land ownership of the major airports remained with the national or municipal governments, this took the form of management contracts rather than full privatization. this transformation of aviation governance after the first decade of the twenty-first century was also affected by the socio-economic context stemming from chronographic and chorographic interactions. the following section examines the case of the tokyo metropolitan area's efforts to deal with the complicated interactions underlying the recent transformation of aviation governance. in this section, we examine the transition in terms of location, governance, and functions of the three airports in the tokyo metropolitan area-namely, haneda, narita, and ibaraki (fig. . ) . first, in relation to japanese aviation governance since the s, we examine the transition and development of the airports in the tokyo metropolitan area. takamatsu ( ) has identified three phases in the transition of japanese aviation governance from the s to the present. first, during the post-war reconstruction period, the japanese government established airport systems through public funding and government leadership to stimulate the development of the airport industry in japan (from the to the s). second, along with the establishment of the domestic airport system through public initiatives, the government promoted aviation liberalization in the s and s. finally, drastic changes occurred in aviation governance beginning at the start of the twenty-first century, compared with the situation when the airport industry was established. in the first period of aviation governance in japan, the japanese government dominated the aviation industry and its operation. details regarding operating systems in domestic airport companies and related businesses were determined by the national government, which was also responsible for developing the domestic airport system. refurbishment and new construction at haneda airport commenced after the united states occupation forces partially returned control over haneda air base to japan from to (mlit kanto region office ). government-controlled aviation systems were officially launched in the fiscal year , and the government started to formulate long-term plans for aviation systems in (takamatsu ) . the rapid increase in air transportation exceeded haneda airport's capacity, even if the airport were to be extended, meaning that a new airport was required. in , the ministry of transport (formerly the mlit) was determined to establish the public corporation naa to manage the operation of a new airport. in , the national government selected narita city in chiba prefecture as a possible site for this airport (narita international airport corporation ), but this was strongly protested by local farmers. later, radical activist groups joined the protests, resulting in a series of terrorist attacks, multiple deaths (including suicides in the aftermath of these attacks), and numerous injuries during the s through the early s. meanwhile, the demand for air transport continued to exceed the capacity of haneda airport, which was problematic. opening a new airport became an urgent priority for the government, which took political action to obtain land through eminent domain for the construction of a new airport in . this fueled even more vigorous protests. after several postponements, narita airport was finally opened in (naa ). the abovementioned protests and concerns about residents' health because of noise pollution resulted in restrictions being imposed regarding the time of day when aircraft could depart from narita airport. moreover, many local landowners continued to protest against nearby airport-related development, and the national and municipal governments introduced special measure laws and organized official meetings between airport representatives and area residents to discuss the allocation of public funds to the improvement of urban infrastructure, the residential environment, and public and cultural facilities. as a result of these efforts, tax income from narita airport and related companies, and cooperation between the public sector and residents' associations, narita city is now often listed among the most livable cities in japan (kubo et al. ; see also chap. ). after the opening of narita airport, haneda airport focused on domestic flights and narita concentrated on international flights. during this first period in the development of aviation governance, strict government control over the operation of airports, the limited capacity of haneda airport, and protests related to the establishment of narita airport affected urban development around the airports. people expected airports to be built away from settlements, and the "not in my backyard" mentality was widespread at this time. however, the situation changed with the progress of globalization and the consequent demand for new airports as urban development hubs in major metropolitan areas. the second period of aviation governance in japan was characterized by a dual system consisting of the continuation of the ministry of transport's strong leadership in managing airport systems and the rise of capitalist competition among private entities involved in the aviation industry (takamatsu ) . the deregulation of the aviation industry began during this phase. international flights, which had traditionally been dominated by japan airlines, the national public airline, were opened to other airline companies such as all nippon airways. furthermore, competition among domestic carriers was stimulated, and japan airlines was privatized. in addition, the ministry of transport allocated significant public funding to airports in major metropolitan areas. from the s to the s, suburban areas horizontally expanded beyond prefectural boundaries. in conjunction with the development of narita airport, narita new town was built for employees of the airport and related industries. a variety of housing types and prices in the new town created a welcoming environment both for these employees and for workers commuting to central cities such as chiba city and tokyo (kubo et al. ) . the special measure law on urban development near the airport ensured that the new town offered a pleasant and walkable residential environment. the law also stimulated urban development in the rural areas surrounding the airport and the old center of narita city, which had prospered since the tenth century as a temple town of the mount narita shinsho-ji temple (suzuki et al. ) . the horizontal expansion of the suburbs and an increasingly car-oriented lifestyle required new development and investment. national policies and public interventions accelerated the building of highways, high-speed railways, and other urban infrastructure in the suburbs (abe et al. ) . the government relocated some urban functions from central tokyo to the surrounding suburbs, and public interventions promoted suburban development from the s to the s (abe et al. ; kubo ) . for example, major research institutions and the tokyo university of education (now the university of tsukuba) were relocated to tsukuba science city in a project led by the national government. in addition, industrial parks were developed in areas with a high level of transportation convenience such as kashima port; the cities of chiba, yokohama, and saitama were selected as sites for new office-center development in the suburbs; and the national and municipal governments promoted multi-functional urban development (see fig. . ). in relation to the airport specifically, large parking areas, shuttle-bus service between the airport and nearby parks and hotels, and railways connecting narita and central tokyo were developed in response to rising demand from international travelers as japan's economy grew during the s. the bursting of the economic bubble in the s affected development around the airport, and the neo-liberal policies that were adopted in the following decades fueled the transformation of aviation governance and urban development in the tokyo metropolitan area. the mlit's aviation subcommittee reports in and and the amendment of the airport development law of have strongly affected the environments surrounding airports and the airport-related industries (takamatsu ) . now, in the face of economic globalization and neo-liberalization, two primary goals have been announced: increasing the competitiveness of major japanese metropolitan areas in the global market and improving the economic efficiency of airport management. the government has transferred its dominant role in the management of air transport and airport operations to private companies. at the same time, major japanese metropolitan areas have undergone a dramatic transition from suburbanization to the recovery of the city center. in tokyo, this has largely been the result of neo-liberal policies such as the urban renaissance special measure law of and related policies launched by the national and municipal governments (kubo ) . these initiatives have led to the concentration of public and private investment in central tokyo since the beginning of the twenty-first century (hirayama ) , and proximity to transportation systems connecting key facilities with central tokyo has become increasingly important. the strong and widespread desire for better access to transport systems also applies to urban retail, business, and entertainment developments. more urban facilities have thus been built near transportation cores such as train stations, bus terminals, and airports. along with the deregulation and new urban development trends, haneda airport's terminals were rebuilt to include facilities such as event halls, wedding venues, and shopping malls (haneda tokyo-international airport ). in addition, national (the mlit), municipal (metropolitan tokyo), and lower-level (ota and shinagawa wards) governments implemented a town plan involving haneda airport and its surrounding areas in (the council of haneda airport relocation problem ). the zepp haneda entertainment hall, which is the main facility of the townplanning project, will be completed in . this project aims to utilize airport areas for the development of retail, business, and entertainment facilities, while also maintaining parks and recreation facilities for residents. the re-internationalization of haneda airport and the opening of ibaraki airport both occurred in , enabling better access between central tokyo and major transportation hubs (tanaka ). at narita airport, in addition to similar renewal projects to that undertaken at haneda airport, development aimed at addressing the increasing needs of inbound tourists began at the beginning of the twenty-first century. this was partially because narita airport's popularity rapidly declined following the re-internationalization of haneda airport because of narita's distance from central tokyo (see fig. . ). the mlit launched the "visit japan" campaign in the first decade of the twenty-first century to stimulate inbound tourism to japan, and international airports were expected to play dual roles of both nodes and destinations for inbound tourism. in the narita region, the increase in asian tourists in the first decade of the twenty-first century fueled the development of urban tourism in narita city. hotels offered free shuttlebus services connecting the airport, hotels, the narita train station, shopping malls, and the old temple town. meanwhile, narita city published tourist guides in several languages and developed an english-language website providing information for tourists, and many restaurants and local shops in the old temple town and shopping malls prepared multilingual menus or brochures to welcome international tourists (suzuki et al. ) . the third airport in the tokyo metropolitan area, ibaraki airport, which is run by a governmental corporation, commenced operation in . it offers both domestic and international flights, the latter mainly to east asian countries, using low-cost carriers and private charter flights (ibaraki airport ). this airport is connected to central tokyo by a highway system and bus service. with the most affordable bus service and the lowest landing fees of the three airports in the tokyo metropolitan area but with limited facilities in the airport building, ibaraki airport was intended to serve as the secondary airport in the tokyo metropolitan area (ibaraki airport ). the three airports serving the tokyo metropolitan area play complementary roles in improving tokyo's global competitiveness, resulting in different urban development strategies. haneda, as the most important hub with the best access to central tokyo, offers diverse urban functions both in the airport buildings and in the surrounding zones. with a similar level of urban development, narita serves as a node connecting several tourist attractions in the region, and ibaraki supplements the other airports' operation by addressing the need for low-cost carriers and private charter flights. figure . shows a comparison of the functions of these three airports, each of which plays a different role and fulfills different urban development functions. haneda represents vertical, transit-oriented development, along with the central city revival trend in tokyo. narita is characterized by horizontal and network-based urban development, and ibaraki exemplifies the traditional location of airport developments, isolated from residential areas and having less effect on nearby regions. in the age of globalization and neo-liberalization, the three airports in the tokyo metropolitan area play complementary roles in forming a unique spatial structure in terms of urban development. the chronology and chorology of aviation governance at each airport, evident in changes in policies, urban development trends, the socioeconomic context, and human behavior, have led to these differences among the three airports. in this section, we summarize the findings highlighted in this chapter. figure . provides an overview of the tokyo's transformations in spatial structure and their driving forces over the centuries. we focus on the economy, urbanism, development, and transportation as driving forces. from the s to today, tokyo's city regions have expanded west of the musashino terrace. the city regions formed a conurbation along with the development of the factory system, which scott ( ) has termed "the first wave of capitalism." the government and businesspersons such as shibusawa eiichi established the modern railroad system, and entrepreneurs applied western urban planning methods in japan. factories and housing for employees supported the expansion of city regions west of tokyo. suburban development then gradually expanded to the north and the east. the ecological model of the urbanization process, which focuses the ecological model of the urbanization process was established by the chicago school and its followers. the most well-known variations of this approach are the concentric zone model (burgess ), the sector model (hoyt ) , and the multiple nuclei model (harris and ullman ) . abe ( ) examined early studies in the field of japanese urban geography by kiuchi ( kiuchi ( , and tanabe ( ) , which attempted to apply these models to japanese cities. yui ( ) reviewed late twentieth century western studies on housing and urban residential patterns (johnston ; knox and pinch ; robson ) and concluded that each of these western models assumed urban residential segregation in terms of income, race, and class. therefore, we cannot directly apply these models to japanese cities where these forms of residential segregation do not exist, there may be less ethnic diversity, and housing market conditions and family structures differ from those that spatial structure urbanism / transportation / development the s to the s the first two decades of the st century developments along rail lines by private companies (the first wave of capitalism) th century urbanism from the s to the s, the mass production economy ("the second wave of capitalism", scott ) required the horizontal expansion of the metropolitan area. government intervention in urban development, transportation, and the housing market led to suburban homeownership becoming more popular. to supply this type of housing to the growing middle class, suburban development expanded beyond prefectural boundaries, reaching a km commuter belt at the peak of suburbanization and integrating prefectural centers such as mito city into the tokyo metropolitan area (see also chap. ). in addition, there has been a suburban relocation of some previously urban functions such as research institutions (e.g., tsukuba science city) and industrial production facilities requiring proximity to transportation systems (e.g., ports, highway interchanges, or airports). a new airport was established, and the complementary roles played by haneda and narita airports supported tokyo's growth. suburban mixed-use developments such as makuhari new city were built by the national and municipal governments within a km commuter belt around central tokyo. the suburbs within a - km commuter belt became the focus of housing estate developments targeting the middle classes in the tokyo metropolitan area. since the beginning of the twenty-first century, tokyo has experienced spatial restructuring alongside globalization, neo-liberalization, and a shift toward a cognitive-cultural economy under "the third wave of capitalism" (scott ) . the national and municipal governments have promoted the renewal of the city center through the deregulation of urban planning and of the housing and mortgage markets. they have also encouraged transit-oriented development, and major train stations, highway interchanges, and airports became hubs for urban development. with global competition among cities, the long-term economic stagnation in japan, and ongoing social changes, the continuous investment in and growth of central tokyo are becoming increasingly important. to create a "strong tokyo," entrepreneurial urbanism emerged at the beginning of the twenty-first century, positioning central tokyo as the clear winner. a focus on urban redevelopment and the consequent population growth in the city center have fueled this trend over the past two decades. in this context, suburban neighborhoods face challenges related to aging populations and increases in vacant housing. although government intervention is necessary, there are limited possibilities for the outer suburbs in terms of revitalization and growth. the sharp contrast between the growth in the city center and the decline in 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geographical strategies to make better solution key: cord- -gd bacv authors: paul, arpan; sen, joy title: a critical review of liveability approaches and their dimensions date: - - journal: geoforum doi: . /j.geoforum. . . sha: doc_id: cord_uid: gd bacv the last few decades have witnessed increasing trends in urbanization as a global phenomenon. in this regard, the concept of liveability has appeared as elementary for evaluating the degree of living standards of cities. the present review investigates a comparative critical assessment of the existing liveability approaches in urban studies. based on the assessment, the review concludes that a gap prevails concerning liveability approaches between global cities in different parts of the world. the last few decades have witnessed rising trends in urbanization as a global phenomenon. at present, more than % of the world population lives in urban areas. based on evaluations by the united nations ( ), the share of urban population is estimated to increase by % by . the increase could drive urban areas heading for better socioeconomic prosperity and enhanced community wellbeing (world bank group, ) . according to the united nations ( ), the concentration of urbanization driven demographic shift is a prominent feature in the global cities (mouratidis, ) . in this regard, research on liveability and its impact on the community wellbeing are gaining significant grounds (kyttä et al., ) . policymakers and urban practitioners seem progressively engrossed with raising arguments favouring explanations of existing liveability practices around the globe (ruth and franklin, ) . most of them have considered the idea of liveability from an urban sustainability point of view (zhan et al., ) . improving liveability through socio-economic equity and decreasing the environmental impacts of multiple urban operations, owing to the fast speed of urbanization is the main concern of this approach (li and weng ) . as a result, policymakers and advocacy groups suggest liveability approaches as the elementary standard by which to assess the depth of living standards of cities across the globe. the review presents a critical assessment of existing liveability approaches. in general, liveability is the sum of the socio-physical and socio-cultural factors that can improve and upgrade living standards of any spaces (jomehpour, ) ; with the current crisis around covid- highlighting its centrality. the concept, as it is used today, first appeared during the s in vancouver as a strong linguistic mechanism with the electors action movement (mansour, ) . during s the term liveability became a catchphrase in urban studies after donald appleyard introduced it in his book 'liveable streets' (yassin, ) . however, in , the term has gained noteworthy attention as a set of guideline principal from the new partnership for sustainable communities (psc). the paper earmarks that there are noticeable variations in the existing liveability approaches between the east and west (andereck and nyaupane, ; sofeska, ; chen and fazilov, ; mouratidis, ) . scholars, especially from the american and european perspectives, explored liveability researches in the early s (barry, ; rusk, ; kashef, ; chang, ; vela, lerma and ikonomopoulos, ) . however, this trend has started in the east too, especially in asian countries, during early . asian countries, mainly, china, india, malaysia, taiwan and korea, are quite well researched with regards to liveability politics (ellis and roberts, ; randhawa and kumar, ; li and yao, ) . initially, they conducted research based on accessible physical amenities and facilities (wyatt, ; tilaki et al., ; gough, ; kashef, ; xu and guo, ) ; however, in the course of globalization and adoption of liberalization, the trend shifts towards evaluating the socio-economic impacts of rising urbanization within cities has also emerged. the term liveability has been used as a policy approach by those involved in urban governance (li and yao ) . liveability is a holistic paradigm of human development and community well-being, which is based on the augmentation of twin physical-environmental and cultural dimensions of cities and their associated regions (balsas, ; wyatt, certain physical spaces, with appropriate preparedness in the cultural and environmental dimensions as its prerequisite (tilaki et al., ; onnom et al., ; yassin, ) . in most cases, various scholars/organizations derived their explanation of liveability approaches based on their perspectives and contexts of their research. like, clinton liveability agenda ( ) had defined it as a best practice that encourages communities to maintain green space, eco-friendly transportation choices and pursues regional intelligent growth policies for a sustainable future (national research council, ) . australian bureau of statistics ( ), explanation is heavily related to well-being and can also be used in a collective context to define how well a society meets the requirements and needs of its own people (paul and sen, ) . it is therefore evident that the dimensions of liveability approaches include many complex characteristics, urban patterns and forms (farber et al. ) . most researchers and policy makers embrace it as self-explanatory and as a reference to the living standards or overall wellbeing of cities, with several international agencies forging numerous liveability approaches to understand living standards of cities (murray, ; shamsuddin, hassan, and bilyamin, ; onnom et al., ; paul and sen, ) . the global liveability index by the economist intelligence unit (eiu) publishes annual reports on liveability rankings to evaluate the living standards of various cities (economist intelligence unit, ). this ranking is based on five weighted factors, namely, stability, healthcare, culture and environment, education, and infrastructure. followed by, the mercer's quality of life (qol) survey, which ranks numerous global cities in terms of their living standards (mercer, ). mercer's qol survey delivers appropriate recommendations for global cities based on ten selected and recommended socio-economic indicators. in , for instance, vienna (austria) tops the rank across the globe followed by zürich (switzerland) and auckland (new-zealand). the organization for economic co-operation and development (oecd) conducts better life index (bli) to survey to measure liveability based on eleven social-environmental-economic factors. lastly, american association of retired persons (aarp), a public institute, initiates the liveability index for the american cities (american association of retired persons, ). due to the growing pace of urbanization and its association with the population growth mainly older adults, this index focuses on liveable communities based on housing quality, neighbourhood aspirations, transportation options, environmental quality, health, and economic engagements. based on a comparative critical assessment, three findings are evident from these works: • first, it is explicit from the literature that each approach tends to demarcate the idea of liveability in different ways. due to the notion of their assessment procedures, the impressions of liveability have evolved within cities (leby and hashim ) . here, the secondary and tertiary activities are more predominant features, and the impact of human activities on urban environment is a more prominent characteristic (aziz and hadi ) . from socio-economic, cultural, and environmental views, urban areas, especially cities around the world, are getting more attention by researchers to explore different shades of liveability variations and the intrinsic potential for urban and social development within them (li and weng ). • second, it is further evident that cities are a major centre of attraction in terms of economic potentialities, community well-being and hope for the better living standard. people want to live in cities to appreciate the financial benefits with associated amenities and level of services. in this respect, the global ranking tools have touched critical issues linked to peoples' perception of liveability and the degree to which the cities meet their requirements and aspirations. subsequently, urban governance seems to be progressively engrossed with the concept of liveability and become an innovative tool for better shaping the future of cities. • third, cities topping the liveability ranking, namely, vienna, melbourne and copenhagen, are characterized with by high living standard in terms of employment options, access to quality education, health and basic amenities and community-friendly transportation options. based on a study by zhan et al. ( ) ; these factors also attract migrants and aspirants for getting further urban benefits and livelihood opportunities. the comparison is not intended to underestimate the ongoing efforts of these cities to optimize the living environment for their residents and visitors but to contextualize the results of liveable city rankings. invariably, however, global ranking studies also provide some conflicting outcomes. for instance, in other studies, cities that are ranked positively in terms of affordable transportation options by some research may perform badly in some another category opined by another group of researches (uysal, perdue, and sirgy, ; giap, thye, and aw, ) . the reason for this disparity is that the weighting allocated to distinct classifications, such as education, healthcare social equity may not be equal to those for urban services, housing, natural environment, and infrastructure. the comparative assessments differ in various perspectives and contexts. the comparison is conducted not to dilute the notion of living, but to broaden its scope and conceptual boundaries to encompass the critical dimensions of liveability that form the core of residents' good perspective and satisfaction. there are three findings to understand the review of approaches and dimensions of liveability in urban studies. the first finding reveals the existing variations of liveability approaches across the globe. most western cities, especially the american and european perspectives, liveability approaches have been carried out form physical aspects, especially transportation options, transit-oriented development and financial supremacies. however, later onwards, the global east has understood that apart from the physical aspects, socio-cultural dimensions are equally significant aspects for assessing liveability of any cities and regions. the second deals with the conception and dimension of liveability. based on the empirical assessments, the paper demarcates liveability as a composite notion with many complicated features and urban patterns and forms, encompass several multifaceted extents and states of inclusive wellbeing (national research council, ) . the third denotes a contemporary liveability assessment tool to understand the pattern of living standards across the globe. based on the world ranking of cities by some global agencies, the paper has identified a few research concerns in liveability researches in the present context. the three themes as a whole have identified a significant role of community participation and interventions of urban governance to best improve the community wellbeing. therefore, our review underlines the need for a further examination of the dynamics of liveability potential research across cities in different parts of the world. the outcome of such studies will be able to promote exploration of good liveability potentials between cities to improve the decision-making processes for a liveable and sustainable future and to bring back social wellbeing accordingly. the liveability index: great a. paul and j. sen geoforum xxx (xxxx) xxx-xxx neighbourhoods for all ages exploring the nature of tourism and quality of life perceptions among residents linking urban form to a liveable city measuring the liveability of an urban centre: an exploratory study of key performance indicators case studies on transit and liveable communities in rural and small town america some aspects of the urban geography of the chinese hsien capital author (s): sen-dou chang source re-centering central asia: china's 'new great game' in the old eurasian heartland best cities ranking and report. the economist leveraging urbanization in south asia: managing spatial transformation for prosperity and liveability the social interaction potential of metropolitan regions : a timegeographic measurement approach using joint accessibility the social interaction potential of metropolitan regions : a time-geographic measurement a new approach to measuring the liveability of cities : the global liveable cities index three reasons to use liveability as a vehicle for sustainability assessing the livability of the new and old parts of tehran, municipality districts and of tehran urban livability across disciplinary and professional boundaries urban happiness: context-sensitive study of the social sustainability of urban settings liveability dimensions and attributes: their relative importance in the eyes of neighbourhood resident s measuring the quality of life in city of indianapolis by integration of remote sensing and census data trends of liveability in the capital region of taiwan liveable urban areas and new housing typologies-a case study in vila quality of living city ranking is compact city liveable? the impact of compact versus sprawled neighbourhoods on neighbourhood satisfaction measurement and analysis of livability. community and quality of life: data needs for informed decision making development of a liveable city index (lci) using multi criteria geospatial modelling for medium class cities in developing countries identifying factors for evaluating livability potential within a metropolis: a case of kolkata. available at livability assessment within a metropolis based on the impact of integrated urban geographic factors (iugfs) on clustering urban centers of kolkata. cities - exploring liveability as a dimension of smart city mission (india) building sustainable, inclusive communities: how america can pursue smart growth and reunite our metropolitan communities livability for all? conceptual limits and practical implications walkable environment in increasing the liveability of a city understanding the liveability in a city through smart solutions and urban planning toward developing sustainable liveable future of the city of skopje the necessity of increasing liveability for george town world heritage site: an analytical review world urbanization prospects, united nations handbook of tourism and quality-of-life research: enhancing the lives of tourists and residents of host communities, zhurnal eksperimental'noi i teoreticheskoi fiziki evaluation of the life satisfaction and subjective happiness scales with mexican american high school and college students heuristic approaches to urban liveability study on analysis model of key influencing factors of urban environment liveability liveable city: an approach to pedestrianization through tactical urbanism assessment and determinants of satisfaction with urban liveability in china the authors would like to thank anonymous reviewers for their insightful comments. the authors would express their sincere thanks to dr. kanchana n ruwanpura for her valuable comments, suggestions, and constructive ideas which has directed and helped us to carry out the research in a more coherent way. key: cord- -utjng dq authors: kutralam-muniasamy, gurusamy; pérez-guevara, fermín; roy, priyadarsi d.; elizalde-martínez, i.; shruti, v.c. title: impacts of the covid- lockdown on air quality and its association with human mortality trends in megapolis mexico city date: - - journal: air qual atmos health doi: . /s - - - sha: doc_id: cord_uid: utjng dq mexico city is the second most populated city in latin america, and it went through two partial lockdowns between april and may , , for reducing the covid- propagation. the present study assessed air quality and its association with human mortality rates during the lockdown by estimating changes observed in air pollutants (co, no( ), o( ), so( ), pm( ) and pm( . )) between the lockdown (april –may ) and prelockdown (january –march ) periods, as well as by comparing the air quality data of lockdown period with the same interval of previous years ( – ). concentrations of no( ) (− %), so( ) (− %) and pm( ) (− %) declined and the contents of co (+ . %), pm( . ) (+ %) and o( ) (+ %) increased during the lockdown compared to the prelockdown period. this study also estimated that no( ), so( ), co, pm( ) and pm( . ) reduced by – %, and o( ) enhanced by % compared to the average of – . reduction in traffic as well as less emission from vehicle exhausts led to remarkable decline in no( ), so( ) and pm( ). the significant positive associations of pm( . ), co and o( ) with the numbers of covid- infections and deaths, however, underscored the necessity to enforce air pollution regulations to protect human health in one of the important cities of the northern hemisphere. [figure: see text] geographical setting (elevated basin surrounded by mountain ridges), climatological conditions and emission of higher amounts of pollutant have led to poor air quality of mexico city, the second most populated city in latin america (sma-gdf ; calderón-garcidueñas et al., ) . different air pollutants are associated with anthropogenic activities like transportation, industry and construction (sma-gdf ; table ) and the elevated concentrations of particulate matter (pm and pm . ), carbon monoxide (co) and nitrogen oxides (nitric oxide, nox and nitrogen dioxide, no ) during the spring-summer of every year give rise to implementation of the no circulation program (benítez-garcía et al., ; molina et al. ) . similarly, the concentrations of ozone (o ) remain more than the world health organization (who) recommended μg per cubic meter in about % of every year. negative health effects due to air pollution also include specific effects associated with fine particles (gold et al. ; osornio-vargas et al. ; calderón-garcidueñas et al., ) . the government of mexico city has been implementing the program of no-drive days since to restrict the circulation of % of privately owned vehicles and reduce almost % of air pollutants for mitigating the deteriorating effects of air pollution on health (nava escudero ; davis ) . even with the restrictions, the environmental contingency, because of higher levels of pm , pm . , and o , has been regular in the months of april to june with additional air pollution coming through forest fire and the agricultural waste combustion in the surrounding states, as well as new vehicles introduced to the system every year (molina et al. ) . the rapid spread of covid- to more than countries within months of its discovery in china prompted the who to declare the outbreak as pandemic in march (who ) . recent reports from several countries like china (shakoor et al. ; gautam ) , india (agarwal et al. ; panda et al. ; sharma et al. ) , morocco (otmani et al. ) , brazil (nakada and urban ) , saudi arabia (anil and alagha ) , and the usa (pata ; doğan et al. ) have assessed improvement in the air quality from an appreciable decline in many anthropogenic pollutants in response to restrictions imposed on traffic and industrial activity during the novel coronavirus (sars-cov- ) pandemic. in this context, we believe that the estimation of changes in air pollutants from mexico city is necessary for a global comparison. the new data might even provide important clues for implementing new measures or modification of existing strategies for improving the air quality of one of the polluted cities in latin america. by august , the covid- death toll from mexico was the third highest in the world, next to the usa and brazil, with the highest confirmed cases (n = , ) and deaths (n = ) in mexico city among all the federal states (https://coronavirus.gob.mx/datos/). in mexico, the first case of infection was registered on february , , and subsequently, all federal states of mexico presented covid- cases by march , (mexico health ministry ). on march , the government of mexico city announced sanitary emergency starting on april as the number of cases exceeded one thousand by march , (mexico health ministry ). the first partial lockdown was imposed until april and all nonessential activities in the public and private sector, schools and universities were suspended as part of the contention measures. the shopping malls, bars, clubs, zoos, saunas, gyms, and cinemas remained closed and all the individuals over years of age and those with preexisting medical conditions were instructed to follow the stay-at-home measures. circulation restrictions (no-drive days) are generally on place all year long; however, on april , , an extraordinary scheme was implemented, and the vehicular circulation decreased by % due to the mandatory controls (gdf ). in addition, about % of the metro train, metro bus and light rail stations were closed from april , . the government extended the restriction by imposing another period of lockdown until may as the number of confirmed cases increased to (mexico health ministry ). there is no available information about the effects of anthropogenic activities and other sources on overall air quality of mexico city amid the covid- pandemic. thus, the main objective of this paper is ( ) to assess the impact of covid- measures on air quality by evaluating the levels of air pollutants, i.e. co, no , o , so , pm and pm . , between january and may , , and comparing the air quality of the lockdown interval with the same period of previous years, ( ) to evaluate their associations with mobility trends and ( ) to empirically analyse whether or not the concentration level of air pollutants can contribute to the outbreak of covid- . therefore, this very first report, as per our knowledge, evaluated the effect of reduced human activities through covid- lockdown on the air quality of mexico city megapolis. mexico city is the second most populated city of latin america with > million people, divided into municipalities, and circulation of an estimated . million vehicles (conapo ). an atmospheric monitoring system, known as simat, continuously measures o , so , no , co, pm and pm . through the manual and automated atmospheric monitoring networks (redma and rama), atmospheric deposit network (redda) and meteorology and solar radiation network (redmet). the hourly data from rama follows the united states environmental protection agency. the daily concentrations ( h) of so , no , co, pm , pm . and o and meteorological data (i.e. temperature, relative humidity, wind speed and precipitation) were acquired from the official website of atmospheric monitoring system (http:// www.aire.cdmx.gob.mx) for the months of january, february, march, april and may of , , , , we considered the levels of air pollutants between january and march , , to represent the air quality of prelockdown period. concentrations of air pollutants of the lockdown period between april and may , , were compared with the prelockdown concentrations to estimate the short-term changes in air quality during the lockdown period. the lockdown, however, was divided into different periods: pl between april and april , , and pl between may and , . the phase i represents changes (%) occurred in the level of air pollutants of the first period of lockdown, pl (i.e. april -april , ), with respect to prelockdown (i.e. january -march , ). phase ii represents the changes (%) in air pollutants of the second period of the lockdown, pl (may -may , ) with respect to the first period (pl ) of lockdown. the average concentrations in april and may of - , were considered as historical trend and they were compared with air pollutants of the entire lockdown period of to estimate the long-term changes. to better understand the effects of traffic/mobility on air quality, we acquired online data of average traffic count (https://www.tomtom.com/en_gb/traffic-index/mexico-citytraffic/) for mexico city by collecting data from tomtom. it represents change in vehicle movements for each day during the covid- pandemic. basically, the traffic index data is built from users who use tomtom tech in navigation devices, in-dash systems and smartphones. the collected datasets were used to understand the potential relationship between traffic measures and the concentration of air pollutants. we retrieved data of confirmed covid- cases and deaths in mexico city during the lockdown period from the official website of the government of mexico (https://coronavirus.gob.mx/datos/) to find the association between covid- mortality and air pollutants between april , , and may , . statistica (version ) was used to process the data, to perform correlation tests (p < . , . and . ) and to determine the relationship between variables. meteorological parameters of - as the meteorological conditions impact the air quality of a region, we carefully considered the variables of temperature, precipitation, relative humidity and wind speed of the studied interval (i.e. january-may) during - (e.g. chen et al. ). most of the meteorological conditions of the lockdown period of and the same interval of previous years were almost similar ( table ). the average temperature ( - °c) of april-may of , remained almost similar to the average temperature of the previous years for the same interval ( - °c). average precipitation of the lockdown period ( mm) was slightly lower compared to the same months in previous years ( mm). the average temperature of the lockdown interval (april-may), however, increased by °c compared to previous months (january-march) in all the years. the average temperature of the prelockdown period (i.e. january-march between and ) remained - °c, and the average temperature of lockdown period (i.e. april-may between and ) increased to - °c. the average relative humidity ( %) and wind speed ( . mph) of the lockdown period exhibited nonsignificant variations in comparison with the prelockdown period ( % of relative humidity and mph of wind speed). the amount of precipitation during lockdown period, however, was higher compared to the prelockdown period (table ) . air pollutants during covid- pandemic figure shows the mean levels of pm , pm . , no , co, so , and o during prelockdown and lockdown periods in mexico city. the concentrations did not exceed environmental quality standards for air, specified by the mexican government (for pm . = μg/m , pm = μg/m , so = ppm, no = ppm based on -h average, co = . mg/m and o = ppm based on -h average) during the lockdown period. furthermore, all criteria pollutants before lockdown were also within the mexican air quality standard limits. our study revealed important changes in concentrations for all air pollutants due to drastic measures adopted to limit the spread of coronavirus during the pandemic. contents of no , so and pm declined during the lockdown period compared to prelockdown (fig. ) . on the other hand, the concentrations of o increased and both co and pm . fluctuated (fig. ) . changes in air quality (percentage) for the period of assessment i.e., lockdown period (april -may , ) vs prelockdown period (january -march , ) estimated the effectiveness of lockdown on air quality (fig. ) . so concentration showed a maximum reduction of %, and we detected % and % reductions in no and pm , respectively. by contrast, the concentrations of o , pm . and co increased during the lockdown period. most notably, we observed higher augmentation in o ( %), and the concentrations of co and pm . showed increments of . % and %, respectively. furthermore, we analysed changes in the air quality between two periods of lockdown (phase i and phase ii) to better understand the influence of covid- pandemic restrictions on air pollutants (fig. ) . phase i showed much better air quality with significant reduction in concentrations of pollutants during the first period of lockdown (pl ) with respect to prelockdown. in addition, the reduction (phase ii) in second period of lockdown (pl ) with respect to the first period (pl ) indicated that second period of lockdown was also successful with significant improvement in the air quality. for instance, so and no registered % and % reductions in phase i, and both showed further reduction of < % in phase ii. in case of pm , the phase i registered % reduction and the reduction was still higher in phase ii ( %). however, a fluctuating pattern of pm . showed increase of % in phase i and decline of % in phase ii. additionally, we also noted % decline of co in phase i and a hike of % during the phase ii. table shows the change (%) of air pollutants concentration during the lockdown months of compared to the historical trend of same interval comprising of previous years ( - ). the so concentration recorded a maximum reduction of %, while no concentration exhibited % reduction. co and pm concentrations presented almost similar reductions of % and %, respectively. moreover, pm . displayed less reductions ( %) than other air pollutants. however, the levels of o increased by % (table ) . while significant reductions were reported during lockdown compared to prelockdown period of , even much higher reductions in the air pollutants concentration were observed when comparing the lockdown period with the historical trend of - . for instance, no and pm recorded reductions of % and % during lockdown period and prelockdown period, whereas they registered higher reductions of % and % in comparison with -year trend ( - ). even though co ( . %) and pm . ( %) were found increased during lockdown and prelockdown period, a significant decrease of % and % was observed in comparison to previous years. overall, these results clearly indicate that most of the air pollutants significantly decreased during the pandemic compared with the previous years. in mexico city, the vehicular emission is the most prominent source of air pollutants, (table ) . according to the emission inventories of government of mexico, the transportation sector contributes more than tons of pm . into the atmosphere and % of pm (sma-gdf ). the vehicular emission sources account for more than % of air pollutants such as pm , pm . , co and nitrogen oxides (table ) , and it is expected that change in traffic patterns had an important effect on the observed concentrations. therefore, it is necessary to understand the effect of traffic count on air quality during the covid- pandemic. there were . million cars registered in mexico city in and nearly . million in (conapo ). during the lockdown period, the vehicular circulation decreased by % due to the mandatory no circulation scheme (gdf ). in addition, about % of the metro train, metro bus and light rail stations were closed from april , (gdf ). it is important to mention here that the great majority of population rely heavily on public transportation to commute in mexico city. in this regard, we assessed the relationship between the traffic count from tomtom database and concentration of air pollutants (pm , pm . , no , co, so , and o ) during the lockdown period (fig. ) . we observed an immediate change in the traffic volume on april , , when the lockdown measures were implemented (figs. and ) . the daily averaged traffic volume decreased four orders of magnitude in lockdown period compared to the prelockdown period, indicating that only fewer people drove and took public transportation to work, while more people stayed at home. this suggests that the measures were effective and widely followed. furthermore, we performed correlation analysis to explore associations between the air pollutants and vehicular traffic (fig. ) . the relationship between traffic count and pm (r = . ), no (r = . ) and so (r = . ) confirms that reduced vehicular movements led to a significant reduction in the concentrations of pm ( %), no ( %) and so ( %) during lockdown period (fig. ) . moreover, the positive correlations among pm vs no (r = . ) and so (r = . ) suggest less vehicular emission as the principal reason of better air quality (table ). it is important to note that the reduction in so ( %) over the entire lockdown period (march -may , ) is comparable to the reduction ( %) obtained by limiting the use of sulphur bearing gasoline and diesel oil in - and reduced emissions from combustion of fossil fuels in industry and power generation plants (benítez-garcía et al., ) . while the traffic patterns could explain some of the trends observed in air quality, they do not explain all the features such as high concentrations of pm . , co and o during lockdown period. in case of co and pm . , the lack of significant relation with traffic count indicates other sources such as electric energy production and household combustion (sma-gdf ) . certainly, the usage of electric energy and household combustion augmented as people stayed at home and cooked during this global crisis. regarding o , we observed negative correlation with traffic count (r = − . ) and strong interactions with pm . (r = . ; . ; . ) for all the three periods (table ). fine aerosols (pm . ) have longer residence times in the atmosphere in comparison with the coarse fraction (pm ), and their composition determines how they interact with light (salcedo et al. ; aiken et al. ). increase in pm . during the phase i possibly had an impact on optical properties, but it is difficult to know if it was positive or negative without knowing the composition and physical property of aerosol. similarly, the role of nitrogen oxides and other nitrogenated species in o production is also complex in the urban atmosphere. in addition, the average temperature of mexico city during the lockdown interval (april-may) increased by °c compared to previous months (january-march) of the last years ( table ). the strong solar radiations and favourable conditions for photochemical production also lead to peak in o levels during the months of april and may (e.g. chen et al. ) . previous intensive campaigns conducted in the mexico city metropolitan area (i.e. imada-aver, mcma- and milagro; song et al. ; palomera et al. ) had demonstrated the complexity of atmospheric chemistry in formation of the secondary species like o and secondary aerosols. thus, the increment in both the pollutants during pandemic could be telling something important about changes at the chemistry level. the impacts on air quality due to drastic changes in urban function during the pandemic would provide values in negative shows decreased contents and positive shows increased contents compared to the historical trend ( ) ( ) ( ) ( ) ( ) valuable information for the air quality management in mexico city and other cities with similar photochemical pollution problems. air pollution is a concern in mexico as it was responsible for one in seventeen ( . %) deaths in the country with nearly , deaths in (larsen ; alves ) . in a previous study in china, cui et al. ( ) observed high mortality rates in areas with deteriorated air quality during the sars epidemic, a virus genetically identical to covid- . given that covid- is a respiratory disease that could quickly spread to the community and would remain viable and infectious in aerosols for hours (van doremalen et al. ) , this study investigated the association between concentrations of air pollutants and reported daily number of covid- confirmed cases and deaths in mexico city. at end of the lockdown period, mexico city reported , covid- positive cases and deaths. about % (n = ) of the mortality were represented by men and the rest % (n = ) were women (government of mexico: https://coronavirus. gob.mx/datos/). figure illustrates daily variations in air pollutants and daily reported covid- cases and deaths. table summarizes the association between air pollutants and the covid- cases and deaths for the entire lockdown as well as in pl and pl . the correlation matrix revealed a significant association between covid- cases and deaths and concentrations of co and o for all the three periods. pm . , however, showed significant correlations only with cases and mortalities of pl and pl . we observed that the increasing levels of aforementioned air pollutants equally affected the covid- cases and mortality rate, and they were independent of sex. our results show similarities with other studies conducted in other parts of the world. most of the countries show substantial relationship between pm . and covid- mortality rate. identical to this study, xiao et al. ( ) found strong correlation between both in the usa and suggested that the fatality rate can increase up to % by increase in the concentration of pm . ( μg/m ). similarly, yao et al. ( ) identified positive association between higher pm . and pm and covid- deaths in china. in northern italy, setti et al. ( ) recognized strong relationship between both the fine particulate matter and covid- mortality rate. our study also shows strong positive correlations (r = . ; . ) of co with covid- cases and deaths in mexico city. pansini and fornacca ( ) observed that the level of co in the air was positively related with the number of infections in italy, the usa, and china. alike to our study, zhu et al. ( ) reported the association between . % increase in daily confirmed cases in china and o ( μg/m ) enhancement. overall, these evidences indicate air pollutants as a potential risk factor for respiratory infections and increase in covid- confirmed cases and deaths. among the limitations of this study, (i) the emission inventories could not be examined to evaluate the impacts from changed patterns, change in fuel consumption at industrial and domestic levels due to lack of data. a thorough analysis of air pollution with respect to emission during the lockdown would be required in the future research. (ii) we also did not take into account the contribution of air pollutants from water (iv) we did not take into account the contributions of immunology, mask-wearing, hand-washing habits, people gathering and social distancing for evaluating the relationship between daily covid- confirmed cases and deaths. this could be the first study that provides evidence about the association between air pollutants and covid- mortality in mexico city. the future studies should consider these limitations as an opportunity in order to establish mechanisms to improve the air quality. this paper examined the implications of restrictions imposed during two different periods of partial lockdown to mitigate the propagation of covid- on the air quality of mexico city (mexico). contents of no , so , pm reduced and ozone was enhanced during the lockdown period compared to the prelockdown period as well as historical average of the same interval of last years. the observed variations in air pollutants did not show association with meteorological parameters, and they were mainly caused by stringent restrictions on anthropogenic activities during the covid- pandemic. for example, no , so and pm showed strong relationships with traffic count, indicating significant effect of vehicular movements on air quality. the air pollutants mostly diminished during the first period of lockdown (pl ) between april and april , , and the air quality further improved in second period of the lockdown (pl ). furthermore, pm . , co and o were significantly correlated with the confirmed covid- cases and deaths. future studies can provide insight about the interregional response towards covid- pandemic and deliver a better understanding of air quality and the spread of covid- . we also assume that the air pollutants would intensify once the lockdown restrictions are lifted, and this temporary improvement in air quality might help to formulate new strategies to revoke the years of damages caused by different human activities. comparative study on air quality status in indian and chinese cities before and during the covid- lockdown period mexico city aerosol analysis during milagro using high resolution aerosol mass spectrometry at the urban supersite (t )-part : fine particle composition and organic source apportionment mexico: deaths from air pollution the impact of covid- lockdown on the air quality of eastern province. saudi arabia air qual atmos health analysis of criteria air pollutant trends in three mexican metropolitan areas megacities air pollution problems: mexico city metropolitan area critical issues on the central nervous system pediatric impact understanding long-term variations of meteorological influences on ground ozone concentrations in beijing during consejo nacional de población datos abiertos del indice de marginacion air pollution and case fatality of sars in the people's republic of china: an ecologic study saturday driving restrictions fail to improve air quality in mexico city investigating the effects of meteorological parameters on covid- : case study of new jersey, united states covid- : air pollution remains low as people stay at home gdf ( ) nuevas medidas para la fase por covid- particulate and ozone pollutant effects on the respiratory function of children in mexico perspective: air pollution post nuevo coronavirus en el mundo covid- comunicado técnico diario experience from integrated air quality management in the mexico city metropolitan area and singapore covid- pandemic: impacts on the air quality during the partial lockdown in são paulo state from homo sapiens to homo automobilis: revisiting air quality management in mexico city proinflammatory and cytotoxic effects of mexico city air pollution particulate matter in vitro are dependent on particle size and composition impact of covid- lockdown on pm , so and no concentrations in salé city (morocco) photochemical assessment monitoring stations program adapted for ozone precursors monitoring network in mexico city a study on variation of atmospheric pollutants over bhubaneswar during imposition of nationwide lockdown in india for the covid- pandemic covid- higher induced mortality in chinese regions with lower air quality how is covid- affecting environmental pollution in us cities? evidence from asymmetric fourier causality test characterization of ambient aerosols in mexico city during the mcma- campaign with aerosol mass spectrometry: results from the cenica supersite the potential role of particulate matter in the spreading of covid- in northern italy: first evidence-based research hypotheses fluctuations in environmental pollutants and air quality during the lockdown in the usa and china: two sides of covid- pandemic epigrammatic study on the effect of lockdown amid covid- pandemic on air quality of most polluted cities of rajasthan (india) inventario de emisiones de la cdmx contaminantes criterio, toxicos y compuestos de efecto invernadero aerosol and surfacestability of sars-cov- as compared with sars-cov- exposure to air pollution and covid- mortality in the united states: a nationwide cross-sectional study spatial correlation of particulate matter pollution and death rate of covid /china/pm . pm /multiple linear regression association between short-term exposure to air pollution and covid- infection: evidence from china publisher's note springer nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations department of biotechnology and bioengineering, centro de investigación y de estudios avanzados del instituto politécnico nacional, ciudad de méxico, mexicoacknowledgements vcs thanks conacyt project no. "fase i de la remediación de Áreas contaminadas con hidrocarburos en la refinería gral. lázaro cárdenas" for postdoctoral fellowship. the authors would like to acknowledge all the doctors, health-care professionals, police personnel, sanitation workers and waste collectors at the frontlines working silently and tirelessly during covid- outbreak world-wide. we also thank dirección de monitoreo atmosférico-cdmx for making air quality data open access. key: cord- - ljvw vm authors: włodarczyk-marciniak, renata; sikorska, daria; krauze, kinga title: residents’ awareness of the role of informal green spaces in a post-industrial city, with a focus on regulating services and urban adaptation potential date: - - journal: sustain cities soc doi: . /j.scs. . sha: doc_id: cord_uid: ljvw vm urban green spaces (ugs) and the ecosystem services they provide are essential for the health and wellbeing of city dwellers. ugs are increasingly seen as a potential solution for sustainable urban planning and development. informal green spaces (igs), even though they may make up a large share of ugs, are often overlooked in this regard. this study examines residents’ awareness of the ecosystem services provided by igs and their need for redevelopment. the data were collected through structured interviews in the immediate vicinity of selected igs in the polish city of Łódź. Łódź is typical of post-industrial european cities struggling with environmental (heatwaves, cloudbursts), social (aging, depopulation) and spatial (a neglected and dense city center) issues. our results show that residents saw igs as places able to provide a range of services, mostly of the regulating type, and even minor design interventions can improve the attractiveness of igs. taking this into account, we conclude that igs are important vegetated areas in the city, which can be complementary to formal greenery. . moreover, access to ugs has become a pressing environmental-justice issue in densely populated areas (Łaszkiewicz et al., ) . however, city managers are confronted with multiple barriers to establishing new green spaces, mostly due to spatial and financial restrictions (kronenberg, ) . the most commonly desired ugsurban parks and forestsare frequently not sufficient to meet the demand for services due to their location (usually the outskirts of city centers, or even in suburban areas) or limited size or location options, hence the role of alternative green areas has been highlighted, e.g. cemeteries (nordh et al., ) , allotment gardens (soga et al., ) , or residential greenery (battisti et al., ) . one recently studied option involves considering various patches of vegetated areas scattered throughout the city which are not included in the city's planning documents as ugs, but provide numerous benefits to residents (walking paths and pet areas, recreational spaces, urban agriculture lots). such places are referred to as informal green spaces (igs). although they are defined in various ways, in general they are all neglected areas which are not formally recognized or planned for recreational use by inhabitants (rupprecht & bryne, a,b; pietrzyk-kaszyńska et al., ) . it is also possible to create new green infrastructure in dense cities on urban vacant land through smart growth principles such as in-filling, brownfield and greyfield redevelopment/recycling (european environment agency, ; kim, ) . from an ecological point of view, igs have a large potential to regulate air quality, flood risk and temperature and to promote urban biodiversity (bonthoux et al., ; brun et al., ) . this is due to the processes of ecological succession which structurally and functionally differentiate them from man-made and artificially maintained green spaces (kowarik, ; mathey et al., ) . igs also have a potential to act as connectors within a larger green network, providing an ecological connectivity of green spaces as a basis for sustainable and restorative development of a city (e.g. krauze & wagner, ) . even if they j o u r n a l p r e -p r o o f are not intended for recreational use, studies show that igs offer opportunities for spending free time (rall & haase, ; kremer et al., ; unt & bell, ; rupprecht et al., ; brun et al., ) and enable residents to interact with nature (rupprecht et al., ) . despite the rationality of increasing areas dedicated to greenery in cities to mitigate climate change effects (e.g. heatwaves and cloudbursts (grimm et al., ; depietri et al., ) ), cortinovis et al. ( ) noted that the majority of european cities (eu) are experiencing a reduction in urban green spaces, and almost none had halted land development (european environment agency, a ,b, , european environment agency, ) . if some cities have managed to become greener (particularly in the northern and eastern eu), it has been mainly due to urban expansion. these changes also affect shrinking cities, and in every case they trigger negative social and ecological phenomena (european environment agency, b; cortinovis et al., ) . a comparison of urban spatial development strategies among european cities (cortinovis et al., ) showed that achieving a higher population density in a city only co-occurred with enhancing green space availability in few cases. consequently, the incorporation of igs as temporary green spaces in cities could help to address several issues, e.g. eco-gentrification and social exclusion, hydro-meteorological hazards, quality of life for city dwellers, and urban ecosystem health (kim et al., a) . this can be an especially important issue in cities in the transitional phase with shrinking and aging populations, resulting in higher numbers of vacant lots and a loss of green areas . it requires moving away from perceiving those spaces as a spatial and economic burden, and considering them as valuable social and ecological resources in planning processes (kim, ) . if and how people use green spaces depends on their availability, accessibility and attractiveness (biernacka & kronenberg, ) . direct use is strongly related to residents' j o u r n a l p r e -p r o o f perception and how they subjectively assess the area. the benefits of city parks have been explored the most thoroughly (e.g. bedimo-rung et al., ; brown et al., ; langemeyer et al., ; dou et al., ; rall et al., ) . studies generally focus on the cultural ecosystem services provided by formal green spaces (see the appendix a). work covering citizens' recognition of the regulating services provided by urban parks and greenery is much scarcer (e.g. jim & chen, ; bertram & rehdanz, ; see the appendix a). igs have been considered even less frequently (e.g. weber et al., ; mathey et al., ; table ., appendix a). little is also known about the needs of local residents in terms of redevelopment of igs (mathey et al., ) . as the attractiveness of the space plays an important role in how people consider the value of greenery, the perception of igs can be highly diverse. they are perceived as problematic areas which are aesthetically undervalued (e.g. unpleasant spaces, perceived as a landfill or a source of social problems) (brun et al., ) , untidy and dangerous due to the structure of the vegetation (jorgensen et al., ; mathey et al., ) . conversely, some people see igs as useful, valuable, highly natural spaces (brun et al., ) , characterized by wildness, uniqueness (pietrzyk-kaszyńska et al., ) , biodiversity, and tranquility (rupprecht et al., ) . this paper focuses on igs in Łódź (central poland). the aim was to investigate i) the attractiveness and uses of ugs not intended for recreation, ii) the awareness of ecosystem services provided by igs, iii) conservation vs. redevelopment of igs, and iv) favorable uses and management of such sites as a basis for planning decisions and policy intervention. Łódź is the third largest city in poland in terms of population ( , ) and the fourth largest in terms of area ( . km²). prior to the political and economic changes of , it was a center of the textile industry. today it is a typical post-industrial city in a transition stage towards new economic and management schemes. the development of the city took place at the expense of environmental resources. the rapid development initiated in the second half of the th century resulted in dense urban development, air, soil and water pollution, and the canalization of watercourses. the economic and social transition initiated in has led to economic depression (high unemployment, soaring inflation, a significant decrease of gdp) (stawasz, ; kronenberg et al., ) , but it also introduced new socio-cultural patterns, which have caused further urbanization and urban sprawl (kronenberg & bergier, ; wagner & breil, (szukalski et al., ; pwc, pwc, , statistical office in Łódź, ) . different stages of the city's development, as well as its economic and political history, have led to negative effects on the wellbeing of its inhabitants, conditioned by environmental goods and environmental risk (kupryś-lipińska et al., ; krauze & włodarczyk-marciniak, ). in recent years, Łódź has been facing serious demographic challenges such as a rapid shrinking and aging of the population. by , Łódź lost almost % of its population, meanwhile, in other large polish cities, the process was much less dynamic (krzysztofik & szmytkie, ) . the forecast indicates further decline in population by , resulting in a loss of youth and skilled professionals for the region (szukalski et al., ) . it is also experiencing accelerated population aging, in there were . % of population aged years and more, and by it may reach about . % (statistical office in Łódź, ). Łódź also struggles with high mortality and morbidity rates, a low fertility rate and low migration attraction (szukalski, ; szukalski, ; perek-białas et al., ) . furthermore, the city is highly divided in terms of place of residence. the central zone is mainly home to low-income and unemployed residents, while the upper and middle classes tend to live outside the old core of the city. this is due to the fact that instead of allocating funds to the reconstruction and revitalization of the pre-war housing stock during the communist period (after the second world war), efforts were instead focused on building vast residential areas on the outskirts of the city (marcińczak & sagan, ) . this has led to a societal degradation of the city center and to collapse of its physical attributes (marcińczak & sagan, ) . the differences between the city center and its outskirts are also reflected in the health of residents of different zones, e.g. children from the center have a significantly lower body mass and height (rosset et al., ) . a similar effect can be noted for the prevalence of asthma in both adults and children, as well as seasonal rhinitis in children (kupryś & kuna, ; kupryś et al., kupryś et al., , . furthermore, although green spaces cover . % of the city (feltynowski et al., ) , their accessibility is limited, especially in the city center (kabisch et al., ; Łaszkiewicz et al., ; sikorska et al., in press ). according to sikorska et al. (in press) , this statistic also includes arable land, private greenery and unmanaged green spaces, which account for . % of all vegetated areas. consequently, only a minority of residents have access to highquality managed greenery. this especially affects children in Łódź, since only just over % of them have good access to parks. according to the same studies, % of those citizens who do not have formal green spaces in their surroundings do have access to igs. the location of formal green areas in the vicinity of city residents, a high proportion of greenery not being included in urban green space planning and governance, and unequal access to greenery, all make Łódź an important location for analyzing the benefits and management options of igs. j o u r n a l p r e -p r o o f an inventory of igs in the city of Łódź was performed using an orthophoto map ( ) along with the city's vector land use database to exclude formal green areas and define potential sampling plots. preliminary studies were carried out in igs. fenced sites, those with limited access, and those located within housing estates were excluded. in total, five locations were selected for further research (table ., fig. ). most of the sites were located in or adjacent to the low income areas of Łódź with a predominance of tenement houses (only the fifth location is outside the degraded area, but the poverty and unemployment rates are similar, the difference is manifested mostly in the predominance of blocks of flats over tenement houses). the majority of inhabitants do not have access to private and community gardens, nor formal green areas of appropriate quality and size with adequate infrastructure in close distance. two of them represented street greenery (with and without trees, with low levels of maintenance) and three abandoned, derelict sites at different succession phases (with spontaneous pioneer or ruderal vegetation, no maintenance). all sites were selected as the biggest green patches within the neighborhood, and due to proximity of housing. as respondents were randomly selected in the immediate vicinity of the igs, they did not present equally distributed characteristics. we interviewed women and men (the predominance of women in the group is consistent with the male/female ratio in Łódź). among them, the majority were young, aged up to ( people), while respondents were in the middle age (between - ) and were elderly (over years old). just six people had low levels of education, with the majority having attained middle education ( people). there were people who had completed higher education. among respondents, the majority were employed ( people), while respondents were retired, were students and were unemployed. we used the chi-square test (yate's chi-squared test, for a table when at least one cell had an expected count lower than five) to analyze the relationship between the identified ecosystem services and i) variables characterizing green areas (type of igs and percentage of tree cover) and ii) respondents' socio-demographic characteristics. to determine the strength of the relationship between the variables, contingency coefficientsmeasures of association -j o u r n a l p r e -p r o o f were calculated (pearson's contingency coefficient c for a x contingency table, and cramér's v for variables having more than two levels). in order to identify potential cooccurrence of ecosystem services based on the respondents' opinions, we carried out hierarchical cluster analysis (hca) using the single linkage method with euclidean distances. we performed a multiple correspondence analysis (mca, an ordination technique for categorical data) to determine the links between igs characteristic and any desired design interventions. statistical analyses were performed using statsoft inc., statistica . overall, % of respondents recognized that igs can provide benefits to society. the most commonly identified services were retention of rainwater ( %) and providing habitats for plants and animals ( %). foraging for flowers, fruit and nuts was the least common ( %). among cultural ecosystem services, the aesthetic function was indicated the most ( %) and inspiration the least frequently ( %). our results indicate that respondents were more likely to associate regulating than cultural ecosystem services to igs (fig. ) . based on the hca, we distinguished three sets of ecosystem service co-occurrence. the first set contains a high diversity of services, including cultural services (aesthetic function), supporting services (habitat for species) and regulating services (rainwater retention). the second set is mostly dominated by cultural services (recreation, inspiration, educational use), plus one provisioning service (foraging). the third set mainly includes regulating services (temperature regulation, air purification, noise reduction) and one cultural (relaxation) (fig. ) j o u r n a l p r e -p r o o f there were significant relationships with weak correlation between interviewee age and their recognition of just three ecosystem services provided by igs: aesthetic function (chi , p< . , cramér's v = . ), relaxation (chi , p< . , cramér's v = . ) and noise reduction (chi , p< . , cramér's v = . ). elderly respondents were more likely to associate igs with the maintenance of good mental health and noise reduction. aesthetic function was noted more frequently by younger people (fig. ) . the results also revealed a relationship between higher education and recognition of such services as rainwater retention (chi , p< . , cramér's v = . ) and aesthetic function (chi , p< . , cramér's v = . ) of igs (fig. ) . the maintenance level of igs (unmanaged, such as abandoned areas, and irregularly managed, such as street greenery) was related to both the aesthetic function (chi , p< . , contingency coefficient c= . ) and rainwater retention (chi , p< . , contingency coefficient c= . ) (fig. ) . the results also revealed a strong correlation between tree coverage and the perception of such ecosystem services as temperature regulation (chi , p< . , cramér's v = . ), noise reduction (chi , p< . , cramér's v = . ), purification of air (chi , p< . , cramér's v = . ) and maintaining good mental health (chi , p< . , cramér's v = . ) (fig. ) ). almost all respondents (n= ) expressed a desire to introduce changes to the site under evaluation. their answers were grouped into six categories: . orderliness, including cleaning up the area, mowing herbaceous vegetation (grass, herbs, flowers), and pruning trees; . greening measures, such as creating lawns and flowerbeds and tree planting; . functionality, such as introducing playgrounds, recreational facilities for sports and games, walking paths and street furniture (benches); . elimination and substitution by commercial and service buildings; . formalization as a formal green space; . security, such as eliminating alcohol consumption. the descriptive statistics of the categorized suggestions for the design of igs are included in table . the majority of respondents pointed out a need for orderliness, i.e. increased maintenance (such as mowing herbaceous vegetation and pruning trees) and cleanliness (removing garbage). improvements to functionality were suggested almost as frequently as orderliness, and included improvements to passive and active rest with benches, playgrounds or outdoor gyms and walking paths. improvements to the greenery itself were suggested less frequently and included tree planting and beautification, for example with flowerbeds. improving accessibility to a given area was suggested rarely, as was setting up formal green spaces. only % of respondents suggested building up the area and thus removing the greenery. the majority of respondents pointed out an absence of alternative green areas in their neighborhoods, which would allow them to relax on hot days, play with their children or walk their dog. the first two axes of the mca accounted for . % of the inertia (fig. ) in general, this study reveals that (i) residents perceive igs as places able to provide a range of services, mainly regulating services, (ii) even low-scale design interventions can improve the attractiveness of igs, and (iii) igs are regarded as important vegetated areas in the city which can be complementary to formal greenery. the results show that Łódź residents do associate igs with ecosystem services, in particular with habitat provision for wildlife, rainwater retention, air purification, local temperature regulation and aesthetic function. this is consistent with the findings of previous studies, showing that citizens recognize that igs provide a number of benefits (rupprecht, ; kim et al., b) . some studies suggest that cultural and provisioning services are identified more easily than regulating and supporting ones, since they are experienced directly (brown et al., ; daniel et al., ; andersson et al., ; pueffel et al., ) , while services not experienced directly may be undervalued or not recognized at all (scholte et al., ) . our study confirms the results reported by rupprecht ( ) , pietrzyk-kaszyńska et al. ( ), kim et al. ( b) and graca et al. ( ) , showing that people are aware of igs as providers of habitats and regulating services, and that environmental functions of igs are predominant in community awareness. although many research results show that igs are able to efficiently fill a gap in the availability of urban, green recreational spaces (rupprecht & bryne, b; mathey et al., ; pietrzyk-kaszyńska et al., ; rupprecht, ) , in our case the majority of users treated igs as shortcuts rather than destination points (e.g. dog walking); this may have been due to constraints discussed further in the paper. despite a global increase in interest in urban agriculture and foraging for fruit/plants, our respondents did not consider wild plant harvesting (flowers, nuts, fruit) in igs in Łódź. it should be noted that our results do not indicate levels of foraging; they simply show that just % of respondents admitted that igs could be used for urban foraging. this may reflect concerns about whether urban plants are suitable for eating (russo et al., ) , e.g. due to metal contamination (e.g. säumel et al., ; antisari et al., ) . this bias is unfortunate because urban foraging could be an important and widely accessible way of handling environmentally-friendly production and transport of food, and tackling social issues such as poverty (russo et al., ; shackleton et al., ; landor-yamagata et al., ) . more information may be needed on the subject, including issues favoring the development of igs j o u r n a l p r e -p r o o f which may provide food provisioning, for example by introducing natural barriers to pollution (e.g. planting trees along the street (al-dabbous & kumar, ) ). in line with previous studies (rupprecht, ; kim et al., b) , igs are recognized by residents as important wildlife refuges. additionally, studies focused directly on analyzing species diversity at sites with spontaneous vegetation confirm this belief (bonthoux et al., ) . rarely mown or never mown igs, which are frequently found in cities, support flora and fauna which otherwise would not have a chance to flourish (threlfall & kendal, ) . respondents recognizing igs as valuable habitats for species may indicate their general environmental awareness. most studies attempting to link socio-demographic factors with people recognizing or valuing the benefits of igs show no (kim et al., b) or a limited (rupprecht et al., ; graca et al., ) relationship. in our study, respondents showed a high awareness of ecosystem services of igs; this is related not only to their age or education, but also to the features of the site (e.g. tree coverage, management level). however, socio-demographic factors appear to be statistically related with just three ues: aesthetic function, mental health benefits and noise reduction. the aesthetic function of igs was more highly recognized by younger and highly educated people. elderly respondents were more likely to recognize the positive influence of igs on mental health and noise reduction. this could be related to generational variance and age-related needs, which is linked with a higher physical and mental vulnerability of the elderly. the findings are concordant with those by van den berg and van winsum-westra ( ) and van den berg and kole, ( ) , where people with an academic education rated wild spaces as more beautiful, and elderly people displayed relatively high preferences for managed natural settings. contrary to the findings of graca et al. ( ) , we did not find gender-related differences in attitudes towards igs. additionally, our research shows that street greenery makes cities more attractive. we speculate that this may be due to the fact that, unlike other locations, these areas are minimally managed by the city authorities (perhaps mown a few times a year), which is more often perceived as attractive (Özünger & kendle, ) . additionally, street greenery protects against pluvial flooding (through retention of rainwater), which is a highly recognized problem in densely built-up city centers during rain events (wagner & zalewski, ). the answers indicated that the presence of trees on land parcels is particularly associated with noise reduction, temperature regulation and air purification, which may be due to the responders' beliefs/feelings or the increasing availability and accessibility of scientific evidence. the findings are directly in line with research which provides evidence that urban trees reduce heat stress (bowler et al., ) , noise levels (nowak & dwyer, ) and air pollutants (nowak & dwyer, ; escobedo et al., ; nowak et al., ) . furthermore, the presence of trees is related to respondents recognizing mental health benefits of igs, which confirms findings of other studies (gerstenberg & hofmann, ) . additionally, species diversity is sometimes linked with a positive influence on the mental health of urban dwellers (fuller et al., ) . due to various constraints and barriers, such as lack of accessibility, limited local knowledge or acceptance, the cultural services of igs, especially those related to recreation, are not fully exploited (mathey et al., ) . a similar conclusion was reached by our study, where people did not use these spaces for recreation and did not attribute them with educational and inspirational values. since in many cities only cultural benefits make the presence of greenery formally recognized in decision-making processes, and thus protected j o u r n a l p r e -p r o o f under local plans, we consider suggestions for bringing these these benefits to analyzed areas to be particularly valuable. the most common suggestion from our respondents was to improve the orderliness of igs, e.g. through better maintenance and tidying, to make them more inviting. this is in line with other studies showing a preference for manicured, neat and well-kept ugs (Özgüner & kendle, ) and an increased use of igs, such as brownfields, if those were at least minimally maintained (mathey et al., ; hofmann et al., ; farahani & maller, ) . this preference for managed greenery rather than a more natural, wilder appearance was also emphasized in previous studies (hands & brown, ; lafortezza et al., ; hofmann et al., ; rink & arndt, ; jorgensen et al., ) . another suggested change, almost as popular as improved orderliness, was to improve the functionality of igs, for example by adding benches or delineation of walking paths; this is concordant with results obtained by unt & bell ( ) , who showed that the number of users increased when a few pieces of equipment were set in an urban wilderness. the demand for green measures was less popular. the preference for new greenery was largely in line with the provision of manicured space, by indicating flowerbeds and neat lawns. a preference for such tidy formal features was also found in other studies (Özgüner & kendle, ; poškus & poškienė ; sikorski et al. ); additionally, it was shown that the presence of flowers clearly increases the attractiveness of ugs in many cases (e.g. todorova et al., ; lee et al., ; lindemann-matthies & brieger, ) . passers-by also expressed a desire for more trees to be planted in igs. similarly, other studies have shown a fondness for urban trees among citizens (camacho-cervantes et al., ; todorova et al., ; lafortezza et al., ; fernandes et al., ) . some respondents stated that they consider igs to be unsafe. this was mainly due to littering, overgrown greenery and people consuming alcohol. as a result, they proposed j o u r n a l p r e -p r o o f solutions that would improve the safety of the site, which did not always include removing greenery and changing its wild appearance. instead, they suggested for example, frequent inspections by city authorities or municipal police. the problem of perceived safety risks in igs is widespread and recognized in literature (Özgüner & kendle, ; jorgensen et al., ; rink & arndt, ) . the reasons given include dense, unmanaged vegetation, which translates into short viewing distances (bixler & floyd, ; schroeder & anderson, ) , where vegetation interferes with surveillance (jorgensen et al., ) . this can be conducive to antisocial behavior such as dumping rubbish, violence, harassment and drug/alcohol consumption (rink & arndt, ; rall & haase, ) . several studies suggest that even minor maintenance interventions such as trimming vegetation (rall & haase, ; unt & bell, ) can reduce the perception of danger (Özgüner & kendle, ; lindemann-matthies & brieger, ) . our results make it clear, however, that suggestions for design interventions are highly dependent on the type of igs, in particular its size, closeness to roads, tree coverage and type of management. in particular, unmanaged, large igs located far from roads are frequently linked with a need to improve their functionality, safety and orderliness. the presence of trees increases the emphasis on tree-focused activities, such as pruning or planting, and on safety and clean-up issues. some respondents also suggested formalizing igs and integrating them into the city's existing system of green infrastructure, which could be beneficial to the long-term preservation of ecosystem services. these idea is well-known and described in the literature (kremer & hamstead, ; brun et al., ; mathey et al., ) . j o u r n a l p r e -p r o o f scarce greenery in city centers is significantly linked with a decreased life expectancy (e.g. takano et al., ; jonker et al., ) , increased morbidity (maas et al., ), greater risk of allergies (alcock et al., ; ruokolainen et al., ) , cardiovascular and respiratory disease (donovan et al., ) and higher obesity rates (villeneuve et al., ) . contact with nature is known to influence mental health through lowering depression (sarkar et al., ) , anxiety (gascon et al., ) and stress (tyrväinen et al., ; pun et al., ) , improving concentration (ottosson & grahn, ) , and reducing aggressive and violent behavior (younan et al., ) . there are also a number of indirect effects of green infrastructure on wellbeing, emerging from regulating ecosystem services. greenery in cities can help to cool the environment through evapotranspiration and shade provision (bowler et al., ; kleerekoper et al., ; djekić et al., ) , reduce noise nuisance (li et al., ; dzhambov & dimitrova, ; van renterghem & botteldooren ) , and filter particulate matter from polluted air (popek et al., ; przybysz et al., ) . almost . % of Łódź residents have highly limited access to any formal ugs. this has a twofold effect: it places existing high-quality green areas at risk of invasion of housing estates, and increases the effects of eco-gentrification, making the most vulnerable communities more exposed to adverse effects of urbanization and climate change (wolch et al., ; anguelovski et al., ; koprowska et al., ; pearsall & eller, ; rigolon & nemeth, ) . in both cases, igs can serve as important planning alternatives, especially in cities where they are as abundant and widespread as in Łódź (sikorska et al., in press) . their integration into spatial planning systems as new temporary or permanent green spaces can be a viable solution, potentially welcome by residents, whoas shown by our researchare aware of the impact such places have on their quality of life. since cultural ecosystem services are co-created by people and ecosystems (andersson et al., ) , this is likely to set igs in the city fabric by j o u r n a l p r e -p r o o f activities that promote their widespread use. a similar pattern of results was obtained by mathey et al. ( ) : their research into urban brownfields with spontaneous vegetation shows that in the case of redevelopment, spontaneous vegetation should be linked with aesthetic motives as well as traditional concepts of land management in order to meet the residents' preferences for land use. this can lead to higher acceptance by local residents and help spatial planners to combine nature conservation and use of greenery (sukopp, ; mathey et al., ) . moreover, the changes requested by respondents in our research referred to relatively minor interventions that would not always completely change the nature of the site nor impose a burden on municipal services. such balanced intervention can meet the requirements of both people and nature. additionally, the suggestion to plant trees in places with scarce tall vegetation would improve biodiversity and regulatory services. indeed, studies of the influence of revitalization of brownfields conducted by koch et al. ( ) show that redevelopment does not always lead to a reduction of i.e. cooling effects. igs can become areas which provide city residents access to greenery, improving their quality of life. excluding them from development plans can be a critical element of environmental justice. every aspect of intervention in urban areas takes into account their morphology as well as function and connectivity, and should be considered in a comprehensive way as a socio-ecological approach to transitions towards city sustainability krauze & wagner, ). in the Łódź example the majority of the respondents were in favour of preserving igs after only minor interventions. thus expectations were very modest and could be met at very low cost to the city. the claim raised as a response to the absence of alternative green areas in neighborhoods, and lack of other alternatives (private green spaces, opportunities to move out, or spend time outside the city). consequently considering igs in local plans would significantly improve living conditions of interviewed commuters, while simultaneously the interventions (cleaning, creating walking j o u r n a l p r e -p r o o f paths, benches) would have broader positive effect e.g. on vulnerable communities (elderly, children, poor). in the conditions of generally poor health status of citizens, exacerbated by effects of climate change, shrinking and aging population, and struggle with poverty and social exclusion, igs seem to be the easiest, and the most economical way to create multiple benefits to society and nature-based insurance system. lack of formal recognition of igs creates a very fragile balance between green and grey infrastructure, questioning sustainability and adaptability of cities. during preparation of this paper two out of five studied areas have been already lost for housing development. it coincided with coronavirus outbreak followed by enclosure of all formal green areas (still located at half kilometers distance, and separated with barriersbusy streets and railways from study places). the situation became an eye opening event to residents of many city districts, whose daily activities got squeezed to tiny, overcrowded back and front yards. there is however no evidence of changes in the city spatial planning policy while many other european cities started to revise approach to igs (samuelsson et al. ) .  igs in the polish city of Łódź are perceived by residents as places able to provide a range of ecosystem services, especially those responsible for regulating ecosystem processes.  these spaces are not used to their full potential at present; however, local residents have made suggestions for minor design interventions which should change this. the majority of suggestions indicate a desire for improving the attractiveness of igs.  igs are important vegetated areas in the city which should be protected from being built on to complement formal green spaces in Łódź. j o u r n a l p r e -p r o o f the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. longitudinal effects on mental health of moving to greener and less green urban areas the influence of roadside vegetation barriers on airborne nanoparticles and pedestrians exposure under varying wind condition cultural ecosystem services as a gateway for improving urban sustainability assessing green gentrification in historically disenfranchised neighborhoods: a longitudinal and spatial analysis of barcelona heavy metal accumulation in vegetables grown in urban gardens residential greenery: state of the art and health-related ecosystem services and disservices in the the significance of parks to physical activity and public health: a conceptual model preferences for cultural urban ecosystem services: comparing attitudes, perception, and use classification of institutional barriers affecting the availability, accessibility and attractiveness of urban green spaces. urban forestry & urban greening nature is scaring, disgusting, and uncomfortable how can wastelands promote biodiversity in cities? 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sci bull doi: . /s - - -x sha: doc_id: cord_uid: fav esn a novel influenza a (h n ) has been spreading worldwide. early studies implied that international air travels might be key cause of a severe potential pandemic without appropriate containments. in this study, early outbreaks in mexico and some cities of united states were used to estimate the preliminary epidemic parameters by applying adjusted seir epidemiological model, indicating transmissibility infectivity of the virus. according to the findings, a new spatial allocation model totally based on the real-time airline data was established to assess the potential spreading of h n from mexico to the world. our estimates find the basic reproductive number r of h n is around . , and the effective reproductive number fall sharply by effective containment strategies. the finding also implies spain, canada, france, panama, peru are the most possible country to be involved in severe endemic h n spreading. in the recent months, an emerging infectious disease, which was caused by a novel influenza a h n virus, is spreading over the world [ ] . on april th , the world health organization announced a global warning of the h n spreading. as the large-scale transmission has been confirmed (who swine influenza up-dated, http://www.who. int/csr/don/ _ _ /en/index.html), planes were suspected to be a crucial factor of long distance spreading. the rapid infection rise and convenient transportation network inspire epidemiologists to concern risks of another similar pandemic of flu. *corresponding author (email: cao @irsa.ac.cn) influenza a (h n ) is known as a human-to-human transmission disease, which infects people by direct body contact or close airborne contact [ ] . airplane travel is an idealistic and typical obdurate environment for close contacts. in the absence of obvious evidence that the virus is transmitted through airplane to the world, it is probable that the worldwide airline network is the main venue of the transmission. for the instance, many cases reported in united states, canada, south korea and hong kong, china were clarified to be infected shortly after trips to mexico, suggesting that air travel helps the influenza whip around the world. on april th who announced that mexico became a severe infectious region, then many countries re-strained international travels to mexico correspondingly. an appropriate mathematical model should be constructed to portray the epidemic features, including the contact rate per infection, the average infectiousness duration and even the basic reproduction number. the classic epidemiological model, suspected-infected-removed (sir) is usually used to formulate the epidemic process without effective containment strategies [ ] . sir model simplifies the process of contagious disease analysis, by classifying the target population of the disease into three specific groups, the susceptible, the infective and the removed, and formulating the dynamic process with differentiation equations. the hypotheses of sir model is that all groups of a population should be mixed homogenously, thus they have same possibility to be infected. however, these hypotheses were malfunctional under novel h n transmission due to only limited surrounding contacts could probably be exposed to the few patients in the very beginning. instead, susceptible -exposure -infective -removed (seir) considered the limited susceptible population into the sir model [ ] . while the contact rate and the death/recovered/isolated rate could be roughly estimated, the seir model was well posed. however, while the pathology of infectious virus varies by cases, few studies have analyzed the spatial distribution of this new novel virus, which is significant factor to establish control strategies. besides, the control measures should be a feedback introduced to the model so as to affect the infection rate. by may , , who raised the level of global pandemic alert to th phase, which implied that endemic transmissions had occurred in other countries throughout the world. without effective containments, the virus was spreading almost uncontrollably idealistically. on june , , who again raised the worldwide pandemic alert level to phase in response to the ongoing global spread of the h n flu virus. during these days, many countries adopted strict measures to protect their populations from the hazard. as a result, the local transmission process had been "depressed" so that we can focus on figuring out the global transmission by international air travel. while the virus seems to be uncontrolled globally, containments were changed. for example, china changed the overall strict containment to community controls, so it is meaningless to evaluate global evolvement under complicated control measure. therefore, understanding large spatial diffusion of this virus depends on how to construct a general model to estimate the impact of international air travel for transmitting the virus. even if there were no clear evidence showing h n virus originated from mexico, early evidence demonstrated that many outbreaks associate with passengers travelling back from mexico city [ , ] . without sufficient information of air travel destinations from mexico city, the spatial dynamic of epidemic would be hardly to estimate. our study aims to estimate the on-going h n global transmission in early phase. all data were collected from the internet by july , . we introduced a logistic model to seir model, which effectively evaluates the impact of containments. public health efforts to reduce transmission are expected to have an effective impact on control the epidemic. moreover, air travel from mexico city is considered to estimate the preliminary potential spatial transmission. here we explore to understand epidemic features, as well as spatial diffusion of known h n cases and air flights to analyze risks related by the airline accessibilities. worldwide h n data were collected from the internet. dr. henry niman traced the epidemic through rhiza labs and google (henry niman, http://www.flutracker.com). in this case a new strain of influenza virus against which no previous immunity exists and that demonstrated human-tohuman transmission could result in a pandemic with millions of fatalities. early detection of disease activity, when followed by a rapid response, could reduce the impact of both seasonal and pandemic influenza. one way to improve early detection in our study is to monitor health-seeking behaviour in the form of queries to online search engines, which are submitted by millions of users around the world each day [ ] . the data is compiled using data from official sources, news reports and usercontributions and updated multiple times per day. not only the laboratory confirmed cases, but also the similar symptoms were seized through strong search engine, considered to be susceptible cases. fortunately, the data contained detailed descriptions concerned to the records, and provided relative accurate spatial locations of all infections, implying a potential basis for our study. air travels has a high probability to play a role in spreading the disease. brownstein et al. [ ] studied statistics on influenza death in many us cites collected between and by the centers for disease control and prevention (cdc), along with estimates of the numbers of passengers who travelled by plane within the united states and from there to another country. the study had suggested that air travel might play such a role based on computer models. because airline travel is an essential factor of global transmission, we collected the related air flight information of large airport from real-time air travel internet website (http://feeyo.com/). as we know, the air flight data were usually counted in the end of year by governments in each country, thus the real-time air travels were difficult to assess because of the seasonal travel variance. however, the data used in our study was obtained in may by collecting real-time ticket sale in april of . so the airlines were adjusted by companies in order to minimize their cost by fully load airlines. the number of airline passengers who flew out of mexico were correlated with the frequency of detected confirmed cases worldwide [ ] . cities all over the world were selected in surveillance airline system [ ] . of them were located in united states and some others distributed in epidemic area to represent the tendency of potential transmission. the internet based information provided airline flight number, the department time and arrival time as well as the plane type (http://www.carnoc.com). due to the economic consideration, all airlines were assumed to be full-loaded based on economic optimization, hence the passengers of each flight could be calculated by multiply the maximal load of plane type. the kermack-mckendrick model is a classic sir model for the number of people infected with a contagious illness in a closed population over period. it was proposed to explain the rapid rise and fall in the number of infected patients observed in epidemics such as the plague (london - , bombay ) and cholera (london ) [ ] . it assumes that the population size is fixed (i.e. the population including the death are the same during the period), incubation period of the infectious agent is instantaneous, and duration of infectivity is same as length of the disease. it also assumes a completely homogeneous population with no age, spatial, or social structure. where t is time, s(t) is the number of susceptible people, i(t) is the number of people infected, r(t) is the number of people who have recovered and developed immunity to the infection, β (t) is the infection rate, and γ (t) is the recovery rate. the basic reproductive number, r , equals the fraction of contact rate to removed rate, which means the average number of infections from symptom onset of the infection to the onset of other infected cases. the basic reproductive number represents the contagious ability of the infectious disease. in traditional uncontrolled condition, when r < , each person who contracts the disease will infect fewer than one person before dying or recovering, so the outbreak will die out. when r > , each person who gets the disease will infect more than one person, so the epidemic will spread. the kermack-mckendrick model was brought back to prominence after decades of neglect by anderson and may. more complicated versions of the kermack-mckendrick model that better reflect the actual biology of a given disease are often used. however, the assumption that all population groups were mixed homogeneously scarcely exists. furthermore, effect-tive control measures and vaccination programs will affect the nature of disease distribution over time. in fact, control measures always reduce r in some extend; therefore, the actual number of secondary infections by each case was recorded as effective reproductive number r. with r> , the infectious disease continues to thrive and if r< , chains of transmission will inevitably die out. vaccination, antiviral drugs and isolation could contain the transmission. hence, as the control measures were considered, the lseir model was established to modeling the temporal dynamic of h n transmission [ ] . a logistic model was used to adjust the contact rate in seir model. logistic model has four parameters in response to the second stable value, range, curvature, and inflection's time, which illustrate a well-fit result in demonstrating the epidemic dynamics [ ] . all air flights of significant airports (using international air transport association (iata) station code to generate a web search, and recording the search result by sorting) were collected in this study to trace the airline information in april and may of . the prerequisites for selecting all airports depend on whether they were prominent trade port of a regional international airport. we especially oversampled in north and south america. so simulations of travelling infections were considered to cover migration infections of airport coverage. yet parts of the infections were assumed to move to other countries through second air travel. since the specific ratio of visitors among the infections was hard to measure, we assumed proportion α of the total infections travelling from mexico city. the transfer rate among passengers from one flight to another flight was considered to be μ. assumed an airline ab linked city a and b with a plane type c, the average passengers of this airline between city a and city b could be defined as ab , c n s p = ( ) where n c equals the maximal capacity of plane type c, and s stands for days of the airline schedule per week. thus, the average passengers for n airlines travelled from city a to city b are all second connecting airlines were considered in the model, including the direct airline cities (i.e. mexico-city b-city a). the axiom could extend to the second transfer, excluding the destination or department city occurred again. for instance, mexico-city b-city a-city c as well as mexico-city a-city b-city c is calculated as mexico-city c, but mexico-city b-city a-city b is not calculated in mexico-city b. the infections from mexico were calculated by adding all second connecting airline travelers to first direct airline travelers according to destinations. as the lseir model was applied in this study, the six parameters of it should be defined. the outbreaks of mexico city from april to may were used to estimate them. the data from may to july were used to validate the result (figure ) . because the four differential equations in lseir exist in pairs of possible solution sets, estimating the optimal solution set lead to a dilemma. we adopted an explicit runge-kutta formula to solve the equations. in general, the runge-kutta formula is the effective mathematic optimal solution for ordinary differential equations. however, as these parameters possibly exist in wide dimensional real number space, the variations of lseir should be appreciated. in this study, a computer optimizing algorithm, genetic algorithm, was adapted to fit the equations. a genetic algorithm (ga) was widely used in optimal estimation by using a theory like biological similar process of genetic propagation and variation, providing scrutiny on solving parameters of differential equations. in this study, a general ga estimates the parameters with % confidential. however, on july , who announced not to provide updated data so the afterward parameters are hard to be gained accurately. the population of mexico city was assumed to be million for a reasonable population of an epidemic area in metropolitan. the initial infection number was assumed to be one and transfer rate between airlines was assumed to be . , on which the model output rely a positive linear relationship to the hypothesis. after simulation, all parameters were assessed. according to the definitions of lseir model, essential epidemic parameters of h n could be evaluated. the r , basic reproductive number, was estimated to . , which illustrates an average infection will cause approximately . persons infected at the very beginning. but the effective reproductive number is around . under containments. however, the probability of an outbreak from a single infection would vary significantly in a different situation. although the super spreading events had not been reported like those during sars (severe acute respiratory syndrome) epidemic, the infected numbers from different infections varied according to our early finding. the basic reproductive number for h n flu is less than for sars and some other infectious diseases, but higher than fraser's estimation (r = . - . , based on the mexico data by april th) [ ] . the incubation period and infectious period are . and . respectively, which lead to define the duration of infectiousness is about d (according to cdc of the united states, the incubation period of novel h n is usually - h, regarding the infectious period is judged by cases.). the result also shows the effective reproductive number recede to . after effective containments have been adopted. if r< , the result imply the epidemic in mexico will be phase out. reset the transfer rate to . , and the model output fits the model better. through global air travel, h n infections would be expected to spread to other countries. after the rapid alert had been made by who, it is assumed that control strategies had been adopted by other countries. in our study, the global airlines play a significant role in aiding the distribution of infections. considering the infectiveness duration lasts no more than d (approximately d in our study), and the air travel will cost - days after having been infected, the infectivity will decrease during international journeys. and the subsequent, more numerous, transmissions in other countries would be caused by the secondary or third infection of the original patient visitor from mexico. the flight transfer would delay this spreading but raise a risk for travelers from other countries. most cities in our study are the capital of the country or the state, or the typical famous cities. all cities connect mexico city though no more than two transfers. the flight transfer rate is set on % of total traveler in all these international airlines. three phases of global transmission were considered: ( ) original phase: the international diffusion occurred at very beginning of mexico outbreak; ( ) uncontrolled phase: the local outbreak in mexico exceeds persons. (according to who report, on april , mexico city had more than infections when more than susceptible cases needed to confirm.); and ( ) final phase: the influenza a tends to gradually phase out. at first, the symptoms and pathology of h n were unclear until cdc laboratories in the united states confirmed two cases in california, thus the outbreaks were not noticed. the latent spreading lasted for several days, which lead the actual original outbreaks might be earlier than that from who report and makes our result a lag behind the reported outbreaks. limited cross-infections between native cases and visitors probably happened but did not lead to international concern for a potential pandemic. on april , after canada and spain reported cases, who raised pandemic alter to level , which indicated that the virus might cause "community level outbreaks". two days later, the pandemic alert had to be switched to level , implying that the pandemic was imminent. we assessed the possible world diffusion from mexico. as the results illustrate, neighboring countries to mexico and developed countries have higher risks to have h n migrations (figures , ) . it might because people in developed countries tend to fly more to mexico for travel. the errors in this study may come from interruptions of diverse control strategies. as the containments were implemented, the disease would incline to fade out. moreover, the randomness of infectivity of cases influences the potential endemic outbreaks. in conclusion, this study used real-time airline data to con-duct a rough estimation for the ongoing h n global transmission. the large scale spatial diffusion was portrayed clearly as the virus was spreading through air travel. our estimation validates that a solid relationship between h n and air travel exists, and predictions could be made based on these findings. also, the epidemic features of this novel h n virus, including the basic reproductive number, the infectiveness duration, are estimated and control strategies are discussed. accompanied with the who warning, countries all around the world constructed some measures to contain h n cases, including airline restrictions, strict epidemiological surveillance and related public awareness campaigns. these strategies appear to have controlled the spread of h n effectively. the spreading of this virus by airline travel from mexico was especially analyzed in our study, demonstrating that control of the h n spreading at international flights would be a high priority in avoiding a pandemic. sanitation and antiviral drugs should be used within airplanes first because the narrow passenger compartment forms an ideal place for virus transmission and the cross-infection prolong the time of virus infectivity. because control measures have strong impact on h n spread, our future research will focus on finding out the relationships between certain containment strategies and the spread of h n flu. origin and future distribution of the new a(h n ) influenza virus emerging in north america in pandemic potential of a strain of influenza a (h n ): early findings a contribution to the mathematical theory of epidemics swine flu jumps continents detecting influenza epidemics using search engine query data empirical evidence for the effect of airline travel on inter-regional influenza spread in the united states swine flu goes global the mathematics of infectious diseases. siam review spatial dynamics of an epidemic of severe acute respiratory syndrome in an urban area mathematical modeling and spatial analysis of spatiotemporal data-case study based on sars epidemic in guangzhou. dissertation for the doctoral degree. beijing: institute of geographic sciences and natural resources research key: cord- - dvjaa authors: nan title: administrative boundaries and urban areas in italy: a perspective from scaling laws date: - - journal: landsc urban plan doi: . /j.landurbplan. . sha: doc_id: cord_uid: dvjaa delineating boundaries of urban areas is no easy task, due to the inherent complexity of the problem, heterogeneity of relevant data and little consensus on how to properly measure the results. any such delineation must eventually be cast onto administrative boundaries, an essential requirement for real-world applications. in the effort of relating administrative and alternative boundaries, we investigated in italy the validity of general scaling laws, such as the area-population relation, and proposed a practical application. relying on open data for population, settlements and road networks, we showed the extent to which scaling relations hold for different boundaries for urban areas, and how they compare to each other. we considered, beside italian municipalities, urban areas based on the idea of “natural cities”, obtained using head/tail breaks of areas related to human mobility as an explicit indicator of existence of a city. area-population data for administrative boundaries can be reconciled with scaling relations valid for both the world’s cities data and with those obtained from natural cities, provided an effective area is adopted in place of polygon planimetric area of municipalities. we eventually proposed an aggregation of administrative units using the empirical scaling relation as an objective function for accepting or rejecting pairwise fusion of boundaries. we suggest considering such a method, along with expert considerations, as an additional tool for real-world urban planning as seen from the very general perspective of seemingly abstract scaling laws. virtually all fields of science have investigated and identified scaling laws for many years. studies based on very general laws, such as the zipf's one regarding the rank-frequency distributions in physical and social phenomena following a power-law (zipf, ) , and gibrat's law, describing rates of growth of different phenomena such as private firms and cities (gibrat, ) , date back to the first half of the th century. similar relations where soon found to hold for a wide range of phenomena, and investigated in a substantially large body of literature. geo-spatial, human geography and urban sciences make no exception: examples of studies of city size distributions as power laws can be found as early as in (auerbach, ) . fang and yu ( ) recently compiled a review of more than , research papers on the topic of urban agglomeration studies. scaling relations regarding urban systems imply that there is no special size for a city, nor a special stage of development: scaling relations tend to be universal. a scaling relation for a given set of urban systems implies that all of those cities are a scaled version of one another, which makes their shape, size and expansion predictable (batty, ; bettencourt & west, ) . despite the large number of studies about universal properties of urban systems, and claims of potential applications for planning, though, practical applications seems to be hard to obtain, with notable exceptions (barthélemy, bordin, berestycki, & gribaudi, ; furtado, ) . most of the existing studies aim at showing the validity of scaling relations, through extensive data gathering from heterogeneous sources (bettencourt, lobo, helbing, kühnert, & west, ; jiang & liu, ; fang & yu, ; long, zhai, shen, & ye, ) and development of dedicated analytical and statistical methods (warton, wright, falster, & westoby, ; clauset, shalizi, & newman, ; taskinen & warton, ) . a notable effort has been devoted to the very delineation of urban boundaries, which is crucial to any further speculation about the properties of urban systems. boundaries determine not only the size but also the physical form of cities which, in turn, is deeply related to their inter-urban and intra-urban function. social implications of city forms stemming from plans and mobility within neighborhoods were discussed by park ( ) . a modern view of the relation between form and function was clearly stated by batty and longley ( ) , who recognized the fractal geometry of cities and identified them in mathematical terms with population density functions. more recently venables ( ) argued that the relation of form and function depends on the evolution in time of cities and on the economic interactions in which cities are involved during their development. this is a view of cities as complex entities characterized by emergent phenomena, whose shape is not well defined. the metrics to estimate urban forms are also object of debate (vanderhaegen & canters, ) . a number of different approaches to city boundary delineation exist in the literature, which we will review and discuss in section . nevertheless, in order to aim at any practical application of scientifically sound models one has to face the fact that, political or administrative boundaries exist in any country of the world and at different geographical scales. hence, existing political boundaries have to be considered for practical applications of scientific conclusions (hamilton & rae, ; thomas, jones, caruso, & gerber, ) , no matter what method is used to establish geographical boundaries of cities. in this paper, we assessed the extent to which planimetric areapopulation (a-p) scaling laws holds in italy, with respect to both urban boundaries and administrative subdivisions. we further applied scaling relations to propose a fusion of a large sub set of administrative boundaries on the very general grounds provided by a-p relations. we considered italian municipalities, the national administrative subdivision of finest granularity ( , polygons in year , see section ). next we considered one of the existing definitions of urban areas, based on the idea of "natural cities". they can be obtained from nodes of communication networks, as originally proposed by (rozenfeld, rybski, gabaix, & makse, ) and recently applied in a range of different study areas and data by jiang and jia ( ) and jiang and liu ( ) . such definition of cities, or urban areas, imply different measures of planimetric areas and population distributions with respect to the ones encompassed by administrative boundaries, which we describe in detail in section . to our knowledge, we performed the first delineation of modern city boundaries in italy, based on one of the methods existing in the literature, and calculated scaling exponents for a-p relations. a study of scaling relations in a few european countries, including italy, was previously performed by bettencourt and lobo, . bertuglia, bianchi, and mela, represents a notable reference to urban studies in italy, though not specifically focused on scaling relations but more in general on a science of cities, of the methods and tools used in their analyses, mostly within complexity and self-organization theories. we performed a selection of pairs of neighbouring municipalities and, using distance from the empirical a-p relation as an objective function, we accepted or rejected the fusion of the two municipalities, were the candidate mergers have aggregate population and area. mergers were constrained to be within the same higher-level administrative area, namely one the twenty italian regions. the results of the analysis outlined above are described in detail in section , and discussed in section . in particular, we discuss the similarities and differences between scaling relations obtained within municipalities' boundaries and within "natural cities", and we compare with two existing clustering of municipalities operated by various italian agencies. conclusions of this work are drawn in section . the complexity of phenomena occurring within cities, and contributing to their birth and expansion, have been investigated in many respects, since the early studies. power-law scaling relations are usually studied as a function of the size of cities, taken as their population. scaling was found to hold for city spatial extent (area), total length of networks (street, piping, wiring), economic and social indicators, and so on (bettencourt et al., ) . infrastructures, such as the total road surface and the total length of electrical cables, show a scaling exponent smaller than unity. on the other hand, quantities related to wealth creation and innovation, such as new patents, employment and gross product, are represented by power laws with an exponent larger than unity: super linear scaling signals that as the city size increases, such quantities must do so at an ever increasing rate in order to sustain system development. to make sense of urban scaling, bettencourt ( ) reported about a comprehensive mathematical framework based on a set of basic principles. the complex dynamics of spatial, infrastructural and social variables could be formalized defining a net urban output function. it was used as a measure of urban efficiency, and its maximization could distinguish between optimal and sub optimal cities. the approach was inspired by the explanation of universal scaling relations in plants (west, brown, & enquist, ) , based on resources being distributed through the system by branching networks. that was later generalized to other living systems (west, ) and other domains, including urban systems (west, ) . alternative explanations of urban scaling exists; for example, using cellular automata, wwhite and engelenhite and engelen ( ) and rybski, ros, and kropp ( ) simulated city size and fractality (both widely used to explain self-organized systems) within a percolation model. recently, liu, batty, wang, and corcoran ( ) studied several aspects of urban change and, most notably, advocated adoption of cellular automata-based models by politicians and practitioners. so far, no standardized international criteria exist for determining the boundaries of a city and often multiple boundary definitions are available for any given city (united nations, ) . as a matter of fact, united nations ( ) categorized urban areas in three nested levels, in order of increasing sizes: city proper, urban agglomeration and metropolitan area, corresponding to different areal and population sizes. other definitions exist in the literature and in practitioners work, often contrasting with the definitions above. for example, fang and yu ( ) consider an "urban agglomeration" as a system of "integrated cities", and surveyed , studies published starting from the beginning of th century, in which the same spatial organizations has been termed either as "megalopolis", "city group" and "city cluster". correspondingly, the delineation of cities has been performed in a number of different ways, relying on very heterogeneous data sources, even if no general consensus has been reached on how to delineate a city (masucci, arcaute, hatna, stanilov, & batty, ) . batty ( ) distinguished city delineation methods by three different criteria: (a) population/urbanization density, (b) interactions, described by different kinds of networks, and (c) geographical proximity/contiguity. we reviewed a sub set of them, given then large number of existing relevant studies, and adopted in this work one of the existing methods. differences in city delineation methods imply different levels of aggregation of variables in social, economic and spatial urban-related analyses. this is known as the modifiable areal unit problem (maup, openshaw, ; manley, ) , which may show up in any study associated with the use of data aggregated within geographical areas. it has been investigated in various fields of spatial analysis, such as landscape ecology (jelinski & wu, ) , natural hazards (alvioli et al., ; alvioli, guzzetti, & marchesini, ) and of course road traffic analysis (viegas, martinez, & silva, ) and census data analysis (flowerdew, ) . in this work, we did not explicitly consider maup effects, though grouping a varying number of municipalities into one single boundary clearly falls into that class of problems. one seemingly straightforward tool for city delineation, as an example of density-based methods above, is the use of a map of artificial surfaces, detected using remote sensing (lu, li, kuang, & moran, ) . one can assume that any impervious (or sealed) surface is part of an urban system (ma, omer, osaragi, sandberg, & jiang, ; thomas et al., ) . in fact impervious surfaces are both built-up and nonbuilt-up, and include a variety of objects that can be identified with human locations or activities (steidl, schleicher, & sannier, ) . impervious areas, though, come as raster layers, and the raster grid cells have to be clustered in order to obtain individual cities. this step introduces the additional difficulty of delineating boundaries between areas who might actually have relations, either spatial or regarding human activities: cities are difficult to delineate, and also difficult to study in isolation (bettencourt & west, ) . arcaute et al. ( ) studied data from uk census using different density thresholds for both population densities and commuting flow destinations. they looked at scaling laws of a large set of urban indicators, aggregated within the delineated cities. they found that most of the indicators exhibited a scaling exponent (cf. eq. ( )) very close to unity, thus apparently violating the expected universal regime of either a sub linear scaling for infrastructure and services, a super linear scaling regime for outcomes of social interactions (bettencourt, ) or a linear regime, in principle expected only for goods related to individual human needs . they explained the values of scaling exponents suggesting that two different regimes exist between cities confined within a domestic environment as opposed to those driving international dynamics. along a similar line, cottineau, hatna, arcaute, and batty ( ) performed a sensitivity analysis of scaling relations on the spatial aggregations of census units in france, aggregated in about , different ways by combining criteria that took into account density, commuting flows and population cutoffs. the general conclusion was that scaling estimations are subject to large variations, and that variations with respect to city delineation criteria are neither random nor universal for all the variables under study. as a consequence, even if cottineau et al. ( ) did not propose a "good" definition of city to study urban scaling, and they clarified that the methodological choice should be operated depending on the attribute under investigation. oliveira, furtado, andrade, and makse ( ) proposed a worldwide model to delineate city boundaries using a population density threshold and a distance threshold representing the mutual commuting distance between populated areas, singled out by a local clustering procedure. they used worldwide census data at about km resolution. they found that zipf's law for population holds for their cities, and proposed a list of the most populated cities in the world, according to their algorithm. street networks are undoubtedly proxies for human presence and activity. the study of networks and human mobility, for various purposes, is a field of research on its own and we will not attempt to review it here (barbosa et al., ) . it suffices to mention that studies of spatial networks and their topological properties are very closely related to urban studies (barthélemy & flammini, ) and network optimization is relevant for urban planning (durand, ; barthélemy & flammini, ) . masucci et al. ( ) used intersections of street networks and a parameter-free clustering technique to distinguish between urban streets and rural streets in the uk. clusters obtained from urban streets actually exhibited scaling behaviour, while rural ones did not, suggesting two distinct phases in the process of urbanization. non-physical networks also represent human activities and, thus, the existence of urban areas. for example, shutters et al. ( ) considered the interrelations among different types of occupations and how they eventually define an overall urban economy in six world's countries and showed scaling with city size. yin, soliman, yin, and wang ( ) considered citizen commute patterns obtained from online social network data to define anthropographic boundaries to delineate cities, finding good correspondence with administrative boundaries in the uk. yin et al. ( ) also noted that, while social networks data may have limitations and biases, they also have the important advantage of allowing time dependent and, at least in principle, real-time analyses (khodabandelou, gauthier, & fiore, ) . the relevance of non-physical networks, most importantly of digital communications, was also stressed by batty ( ) , who envisaged the next revolution dictating the shape of cities as the digital one, after the industrial and the electrical revolutions. eventually, as an example of a method probably falling in the category of proximity-based methods described by batty ( ) and jiang and liu ( ) described a technique for delineating city boundaries using street networks to single out individual blocks, defined by the portion of space within closed street loops. the collection of the resulting block areas were found to follow a log-normal (fat-tailed) distribution, characterized by a much larger number of small areas with respect to large areas. the mean value of the distribution was used to distinguish "large" from "small" areas. jiang and liu ( ) noted that a high smaller-to-large (about %- % to %- %) area ratio qualitatively signals the presence of scaling, which was also studied by means of power-law fits. in this work, we applied a variant of this datadriven, parameter-free method in italy. all of the data utilized in this work were either open data available from governmental agencies, data from volunteered geographic information projects or data otherwise available for free on the world wide web (www). we downloaded a vector layer containing polygons representing italian municipalities from the www site of the italian national institute for statistics (istat, ) . a database table associated with the vector layer contained data about population, aggregated at municipality level from census data surveyed in , the most recent one. we did not exploit the full resolution of population data at census section level because we are interested in a municipalitylevel analysis. the next-level political subdivision in italy is represented by provinces and regions. area, population and number of municipalities in individual italian regions are listed in table . from the istat www site we also downloaded an aggregation of municipalities operated by istat itself, based on census and commuting data, which goes under the name of sistemi locali del lavoro (local labour systems, sll). an additional aggregation of municipalities exists in italy, which was prepared with different methods and with different aims (that we do not discuss here), with respect to sll. the second aggregation goes under the name unioni di comuni (udc, literally associations of municipalities). we compared both sll and udc to the aggregation proposed in this work, in section . we downloaded a continental (european) imperviousness layer, available for various years from the copernicus land monitoring service (clms, ) . we considered the layer corresponding to year , the closest in time to the census data year, . the raster layer has m x m resolution and values of the raster cells give a measure of the degree of imperviousness, in percentage. in this work we were interested in any sealed surface i.e., with any imperviousness degree different from zero, as a first approximation. impervious areas included: housing areas, parking lots, railways close to other impervious areas, industrial and commercial areas, various paved and covered soil, and others. they did not include: inactive built-up areas, temporary coverage, sand, dump areas, cultivated areas, and others. we downloaded road network vector layers from the openstreetmap www site (osm, ) . from these layers we extracted the locations of street intersection to generate natural cities, as described in detail in section . . the total number of street segments in the data set is , , (including overlapping segments across neighbouring regions), amounting to , , intersections. eventually, to visually compare scaling relations in italy with independent area/population data for european and world cities, we downloaded data from the www site of the demographia world urban areas, (dwua, ). data were compiled applying a consistent definition of built-up urban areas, disregarding political boundaries that are generally associated with metropolitan areas or sub-national boundaries. this data set was not crucial since our methodology (section ) is not dependent on world's cities data, and neither are our results or conclusions. it was used in the log-log plots in fig. , for illustrative purposes. in the figure, world's cities data are grouped within ten individual countries, five in europe and five elsewhere. we discuss the plots in fig. in the next section. the ultimate aim of this work is to propose a practical application of long-known urban scaling relations, in particular of area-population relations, for the fusion of existing administrative boundaries. a concise outline of the methods used to achieve such a goal is as follows: • we considered municipalities, the finest administrative subdivision in italy, and investigated area-population relations within their boundaries. • we checked the validity of scaling relations using either the total area of municipalities, a, and a reduced (effective) area, a eff . • then, we focused on an independent method for the delineation of city boundaries available in the literature, namely the method of natural cities, based on the idea that street intersections are locations of human activities. • this objective (parameter-free) delineation of city boundaries was used to extract area-population relations, to be compared with the ones followed by the area and population of individual municipalities. • eventually, we singled out candidate municipality polygons for iterative pairwise mergers. mergers were accepted if the overall area and population within the aggregate polygons were favoured by the empirical a-p relation and overlapped a city, rejected otherwise. throughout this work, we commited to the idea that deviations from area-population scaling laws exhibited by some of the points representative of urban areas in the area-population plane (p a , ) measure how each city, or urban area alike, deviates from expectations based on its size (bettencourt, ; west, ; van raan, ) . in fact, a scaling relation of the form: implies that a city twice as large of another city, in terms of population p, is expected to cover a planimetric area = a a , with a and a the area of the smaller and larger city, respectively. establishing if the value of the scaling exponent is larger, smaller or consistent with unity is crucial to understand if data implies an diseconomy of scale ( < , sub linear scaling, or decreasing returns), an economy of scale ( > , super linear scaling, increasing returns), or constant returns to scale ( = ) (the expressions increasing, decreasing and constant returns are borrowed from economics jargon; here they simply refer to proportionality to city size, and have nothing to do with monetary measures). the basics of area-population relations are illustrated in fig. , which shows how well the supposedly existing scaling holds for world's cities data available on the www, not subjected to any kind of processing. the straight lines in fig. were obtained by linear regression of the log of area versus the log of population. in fact, taking the log of eq. ( ) one obtains a linear relation between the logarithms of area a and population p: )) of population data normalized to its average (p p / ), fitted as a log-normal (blue) and as a power-law (green). (for interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) with = log . the values of the exponents (slopes of the linear fits in log-log representation) for cities in europe, for europe altogether (five countries shown in the figure) and for the whole world (the whole set of , data points) are listed in the caption of fig. . the values of regression coefficients are also listed in the caption, along with the calculated uncertainties. bettencourt, and references therein reported similar fits to the ones obtained here. we also characterized the world's cities data set fitting the population data with power laws. to this end, we used the advanced package powerlaw, written by gillespie ( ) for the r programming language. one actually fits the cumulative density function extracted from data with a power-law. such procedure was inspired by the idea behind the zipf's law, a relationship between the sizes s of objects in a set and their rank r, defined as follows: where is the power-law exponent. in the case of cities, size is given by population. the powerlaw package builds a cdf and fits that both with power-law and with log-normal functional forms. it also automatically finds the minimum value under which the data have to be discarded for the fitting procedure to be reliable. we considered population divided by its average as main variable = x p p / . the cdf function reads as follows: which represents the probability of finding an object with size larger than a given size in a given set (clauset et al., ) . fits of the cdf of europe's city population are shown in the inset of fig. (a) , and in the inset of fig. (b) for world's cities. they show that data cannot be described by any of the fits in the whole p range. the power-law fit (green curves) seems to work well starting from the point where the cdfs obtained from data show a marked change in slope, while the lognormal fit (blue curves) seems to fit best the region of extremely large cities. oliveira et al. ( ) recently described a worldwide model to delineate city boundaries and reported about fits similar to the ones in the insets of fig. . our fits and the quoted ones share the relevant feature of a change in slope, which in our opinion makes the use power-law fits more difficult than a-p relations for the practical purpose that we aim to. universal validity of zipf-like power laws, and their usefulness for urban planning, was also questioned by cottineau ( ) . for these reasons, in the methodological part of this work, we did not use zipflike power-law fits of the cdfs to investigate administrative boundaries and urban areas in italy, but we rather used area-population relations as in eqs. ( ) and ( ). we will show that area-population scaling relations can be deduced from data on italian municipalities, provided area is taken into account in a proper way by selecting an effective area actually occupied by urbanization, in place of the entire area of municipalities. to investigate the existence of a scaling relation between area and population of italian municipalities, we first utilized the whole area encompassed by each municipality's administrative boundary (polygon) and raw population data, as provided by istat (see section ). fig. shows a log-log plot of area vs. population raw data (black dots), along with a linear fit (black curve). fits in this figure and throughout this work were performed by the fit function provided by the gnuplot . graphic software (williams et al., ) ; values of slope coefficient in eq. ( ) (the exponent of eq. ( )), and correlation coefficients r are listed in the figure's caption. we note that the slope of the fitted line is not nearly close to the slope of any urban a-p scaling relation; the fit for european cities in fig. is shown in green in the same plot for comparison. moreover, the small value of the r coefficient of the fit signals a correlation to be unlikely in this a-p data set. an imperviousness layer is a measure of how much the soil is sealed by artifacts and, as such, it can be considered as a direct observation of continued human presence. we used the data set obtained from copernicus www site (steidl et al., ) to constrain the area a of municipalities to their effective area occupied by urbanization, by simply cutting the imperviousness layer within the municipalities polygons in a gis. counting the number of m x m pixels within each polygon provides an estimate of urban area. we refer to that as a eff , in the following. beyond administrative boundaries, examples of city delineation from imperviousness maps are abundant in the literature (see e.g. ma et al., and references therein) . we used the imperviousness map only to calculate the effective area a eff occupied by urbanization in individual municipalities. these urbanization clusters, though, were still selected by administrative boundaries and never labelled as "cities". in fact, we decided to adopt a different approach, for the following reasons. typical approaches for city delineation from sealed surfaces are often based on numerical thresholds (number of cells, or density thresholds), to consider groups of grid cells as individual cities. introduction of numerical parameters represents a difficulty of the method. moreover, the raster map resolution represents an additional lower limit to the accuracy of a delineation performed from sealed surfaces. we performed preliminary city delineation (alvioli, ) , based on the imperviousness map, showing that (a) due to the above reasons, the points representing cities on the (p a , ) plane were distributed in a somewhat biased way, and (b) using such points for a linear a-p fit, we found the same slope as in the case obtained from the method of natural cities, described in the next section. thus, we preferred the latter as a parameter-free method, adopted in the remaining of this work. the definition of "natural cities" was inspired by the city clustering algorithm first proposed by rozenfeld et al. ( ) . the original algorithm starts from a collection of point-like populated sites, and performs an iterative clustering of sites within a given radius. iterations end when no points exist within the radius from each of the points in a cluster. the algorithm was applied by selecting streets nodes as starting points by jiang and jia ( ) , who performed city delineation with this approach in united states, finding that the distribution of sizes (i.e. number of street nodes) of the resulting city set neatly follow a zipf-like law. the algorithm was further generalized by using either city blocks as clustering domains (jiang & liu, ) , triangulated irregular network (tin) (jiang & miao, ) , or thiessen polygons (jiang, ) . in all of the variants of the original algorithm, street nodes were taken as a starting point of the city delineation procedure. in this work, we used street nodes obtained from the openstreetmap vector layer as a starting point. we generated a tin network from these points using the grass gis module v.delaunay, separately for the peninsular italy and the major islands, sicily and sardinia. all of the gis operations in this work were performed within grass gis, version . (neteler, bowman, landa, & metz, ) . we considered the area distribution of the triangles in the tin network, calculated its average value and checked that an imbalanced ratio existed within the three sub regions of italy for the number of areas above (smaller number) and below (larger number) the average value: namely, . for peninsular italy, . for sicily, and . for sardinia. jiang and liu ( ) found for comparable quantities in france, germany and uk the values of . , . and . for the ratio, respectively. an imbalanced ratio of large-to-small areas is the signature of a fattailed distribution, and of the possibility of splitting each of the three sets in a meaningful way using the natural breaks rule, discarding areas larger than average. actually, we discarded all of tin polygons with area above average, along with all of the polygons with area below average which were adjacent to a polygon with large area, following jiang and liu ( ) . this last step is a parameter-free replacement for utilizing a clustering radius to single out cities in this work, at variance with rozenfeld et al. ( ) . the idea of natural cities was further exploited in this work to devise a fusion algorithm for administrative boundaries. the aim of this paper is to propose a method for the fusion of administrative boundaries in italy at municipality level, driven by areapopulation scaling relations. the proposed procedure is grounded on our view of the empirical area-population scaling relation as a "performance" assessment of each individual datum in the data set (municipalities, in this case) as compared to expectations generated by the whole data set based on the individuals' size (population, in this case) (bettencourt, ; west, ; van raan, ; o'clery, curiel, & lora, ) . we argue that if a robust scaling relation as a function of municipalities' size (population) can be obtained, the vertical distance on the (p a , ) plane of an individual's representative point from the linear scaling law can be viewed as a measure of its "performance", in absolute value (i.e., considering equivalent both if it is above or below the linear fit). under this perspective, distance of a city's representative point from the scaling law represents a measure of how much the city is making a productive use of available resources. thus, we suggest that one can rank municipalities starting from the farthest from the scaling law. starting from the highest ranking, one can select all of the adjacent (surrounding) municipalities and try and find a candidate polygon to be merged with the central one, based on two requirements: (i) the aggregate areas and populations of the candidate mergers have a representative point in the (p a , ) plane which is closer to the scaling law than both the starting points, and (ii) the two candidates for the merger are connected by an urban area, as obtained by the method natural cities. if both the requirements are fulfilled, the two polygons are merged. the procedure can be iterated until all of the existing polygons have been checked against all of the possible mergers. the requirement (i) is the simplest one that one can devise for such a purpose; one could also adopt more involved measures for ranking performance with respect to an empirical scaling relation. the same goes for requirement (ii), because it seems reasonable that two municipalities can be considered for fusion into a single administrative unit if they share a common city, in a broad sense. the requirement is generic enough that it may be fulfilled by an urban agglomeration of any size, and the range of variation of city size is very large as it will be shown in the following. both requirements, and the whole procedure, are suited to be implemented in a gis with an automatic iterative procedure. the algorithm of the procedure for polygon fusion is described by the pseudo-code in the listing algorithm . lastly, we need to account for coarser administrative boundaries besides municipalities, namely provinces and regions. we disregarded provinces, which have themselves changed multiple times in italy in recent times. we rather focused on regions, of which italy is subdivided into twenty, and whose properties relevant for this work are listed in table . we restricted fusion between polygons of municipalities belonging to the same region, but still used the national scaling law as a measure to accept/reject mergers. in this section, we describe results obtained for the following four main points: . validity of area-population scaling relations for italian municipalities, described in sections . and . ; . delineation of urban areas (or cities) in italy, with a variation of the method of "natural cities" recently introduced in the literature, described in section . ; . pairwise fusion of a few adjacent polygons corresponding to italian municipalities, described in section . ; . comparison among the proposed aggregation and existing aggregations of municipalities in italy. we discuss the four points separately in the following. fig. shows area-population relations built with raw a and p data for italian municipalities (black dots/curve). the figure also shows the effect of constraining the area a of municipalities to their effective area a eff occupied by urbanization, in a broad sense (red dots/curve). in this work, we adopted any level of imperviousness (steidl et al., ) as an indicator of urbanization. we also plotted again data for the european cities (green dots/curve), whose fit nicely compares with the a eff -p result. we explicitly investigated the effect of different definitions of a and p. first, we studied the effect of modifying p with the inclusion of daily commuting data, vs. total a; the effect was negligible. then, we checked the effect of adding and removing pixels overlapping with roads to modify a eff . in fact, in the imperviousness layer roads may or may not be correctly identified so this step is not trivial. we found that adding missing roads reduces the slope of the scaling relation, which nevertheless still falls within the range proposed by bettencourt ( ) , while removing all of the roads again has negligible effect. eventually, we checked that the effect of modifying p using commuting flow data vs. the a eff plus roads areas in conjunction. this seemed the most accurate approximation we could devise, since people actually spend time on roads too. again, we found no substantial change with respect to the red curve in fig. , which did not account for commuting. we may deduce from fig. and from the considerations above that either using the only impervious area a eff , or a eff plus roads, produce a reasonable scaling relation against p, regardless of the use of modifications to p due to commuting data. we also note that the a eff -p relation, red line in fig. , compares well with european cities data. thus, we adopted the a eff -p linear fit as a baseline scaling relation in the pairwise fusion of municipalities. we performed delineation of urban areas by using the idea of "natural cities" built from the bottom-up using the tin network obtained from street nodes, as described in section . . thus, in this work we compare results of three different approximations of a-p relations, namely: (i) plain area a of municipalities vs. p, (ii) impervious (or effective) area of municipalities a eff vs. p, (iii) area from cities calculated with the natural cities method vs. the corresponding population. delineation of cities based on the "natural cities" method, resulted in a total of , urban agglomerations; additional numerical details are listed in table . fig. shows a map of cities delineated using the method of natural cities. we operated delaunay triangulation from street nodes independently for the three major geographically disjoint sub sets of italy, namely peninsular italy, sicily and sardinia. we found instructive to compare the three different approximations (i)-(iii) listed above from which we built the different a-p scaling relations. fig. shows results for sicily, to allow a larger-scale comparison. the comparison is still qualitative, but one can appreciate the differences. transition from approximation (i), fig. (a) , to approximation (ii), fig. (b) , clearly shows the difference in area measured by the corresponding scaling relations in fig. , black and red curves/dots, respectively, within municipality boundaries. when such boundaries are removed, as in approximation (iii) fig. (c) , areas are computed for the distinct clusters singled our by the natural city delineation method. fig. shows a quantitative assessment of a-p relations within the approximations (ii) and (iii). the figure shows separately data for peninsular italy, sicily and sardinia, where urban areas were delineated separately. the plot show a single linear fit, corresponding to aggregate data for the whole of italy. the linear fit goes into the direction of slightly decreasing the slope obtained in case (ii). data nicely distribute on the (p a , ) plane, clearly hinting to a linear correlation. some patterns seem to emerge, mostly as collinear structures to the overall linear fit in the sicily and sardinia sub sets, suggesting that some minor bias might occur in the case of delineation of natural cities in smaller areas. we used the natural cities delineation for the polygon-fusion procedure, the final aim of this work. the procedure for pairwise fusion of polygons representing municipalities is iterative. we started selecting the polygon whose representative point on the a-p plane is farthest in the vertical direction from the red curve in fig. , the empirical scaling relation for municipalities. fusion is pairwise, meaning that for each polygon we checked for another candidate polygon at a time to be merged with. this means the outcome of the procedure depends on the order of selection of both candidate polygons; nevertheless, for each checked polygon there were often only one or no acceptable mergers, making the dependence on the order of choice rather weak. the algorithm of the procedure for polygon fusion is described in detail by the pseudo-code in the listing algorithm . polygon fusion was restricted within individual regions in italy, a higher-order administrative subdivision, because mergers across different regions would be very unrealistic. the overall process was performed in parallel by gis procedures. each procedure goes to completion i.e., checks all of the existing polygons and performs the possible mergers according to the requirements described in section . , in a few hours. at the end of the run, we re-calculated the new fitting parameters , of eq. ( ), when the individual results obtained for each region were collected in one single map. the result for the new parameters of the national scaling law is substantially the same as for the parameters obtained from the original polygons. to visualize the effect of the fusion procedure, fig. shows a few examples among the few hundreds mergers operated by the proposed algorithm. in the figure, examples are shown of mergers between a point above and a point below the linear fit, and of examples of both points below the fit. examples of both points above the fit occur rarely, because the cumulative area being larger than both the original points would often cause violation of the requirement for the new point to be closer to the linear fit on the vertical (a) direction. the figure also shows three of the many mergers undergone by the largest municipality, including the city of rome, which after applying the proposed procedure would incorporate many neighbouring municipalities, as shown in fig. . fig. shows a pictorial representation of the performance of the original subdivision, consisting of polygons, and of the subdivision after the fusion procedure, consisting of polygons. the figure shows only new polygons of the proposed delineation, for clarity of presentation. the performance is measured as the vertical distance (in powers of ten) of each representative (p a , ) point from the empirical scaling law. note that, in this acceptation, the vertical distance represents the amount by which each a eff exceeds or falls behind the expectation suggested by the scaling law, given the municipality's population. at variance with the procedure itself, in which vertical distance was taken in absolute value, we have coloured each polygon in fig. in classes: a central one, in grey, four classes below the scaling law and four classes above, to visually distinguish points falling below or above the fit with different colour ramps. the below-above classes are symmetric, and were dictated by a data-driven classification using the head/tail break method with respect to the vertical distance of each point from the scaling law, in the log-log scale. table lists the number of polygons and the total area a (not a eff ) in the different classes. since we performed the procedure for the fusion of boundaries within administrative regions, we show in fig. the corresponding individual results. the figure includes a eff -p points for existing municipalities (labelled as "in") and the points for the new delineation ("out"), along with the initial and final slopes of the fits calculated within each region. the figure aims at illustrating differences between the various regions, but in the fusion procedure we always used the national scaling law. it is interesting to compare the proposed aggregation of municipalities with two existing ones, namely the sll and udc introduced in section . fig. (a) shows the a-p relation of sll (cyan) in which we used effective area for all of the data sets included in the plot. local labour systems, consisting of polygons, are substantially larger than municipalities, , polygons, and the fit to sll (cyan, dashed curve) has a less steep slope then both the fit to existing municipalities (grey, solid curve) and polygons after the mergers (brown, dotted line) suggested in this work. the udc layer contains modified polygons, while our new layer contains new polygons with respect to the existing municipalities layer. the total area of the "new" polygons in udc is , km ( "old" municipalities), which compares to the , km ( "old" municipalities) of the new subdivision proposed in this work. fig. (a) shows only the new points contained in udc (blue) and in the new delineation (brown), clearly highlighting that the former contains a bias towards larger areas with respect to the existing administrative boundaries (grey), failing to generate a corresponding increase in population within the merged polygons. similar considerations holds for the sll described above. in this work, by construction, each "new" polygon has to follow the general trend of the empirical area-population scaling law better than both the two original polygons. a chance for direct comparison is provided by official data in italy (istat, ), which reveal that the number of municipalities in italy in the last decades have decreased from , in , to , in . we applied the polygon fusion procedure to data, municipalities, because census data was available to us only for that year. fig. (b) shows that the points representative of the only new (aggregated) municipalities on the (p a , ) plane are distributed in a rather different way with respect to the points representative of mergers proposed in this work, deviating from the national scaling law. we stress that in fig. (b) the population used for the boundaries was from , because the data were not available to us at the time of writing. an area-population relation built with raw a and p data for italian municipalities, shown in fig. (black curve) , is far from any scaling law defined in the literature for world's cities (cf. fig. ) . a meaningful scaling law is found instead by restricting the area a of municipalities to their effective area a eff occupied by urbanization, in a broad sense. a similar quantity (namely, paved areas) was also investigated by bettencourt ( ) , therein referred to as a n . it was reported by the reviewed literature to scale with population with exponents in the range [ . , . ], which includes the range obtained in this work for municipalities' effective area, = ± . . . bettencourt ( ) also mentioned (in the paper's supplementary material) that up-to-date estimates of cities' paved area from remote sensing is desirable. we believe that the data sets used in this work, available from the copernicus programme homogeneously for the whole of europe at high resolution and with constant updates, should be considered for similar studies at continental level and for time-dependent analyses (clms, ) . the definition of criteria for the study of time evolution of urban systems was considered by different authors table for numerical evaluation of the results, fig. for comparison with administrative boundaries and fig. for a eff -p relations. statistics for the administrative regions labelled with three-letter codes are listed in table . map is in lambert azimuthal equal area (laea) projection, epsg: . ), and projections for the future until year also exist by authoritative organizations (united nations, ) . this is a relevant point, since the whole world's population is expected to live in cities of some form in the near future, though city size distributions are expected to experience little change (batty, ) . delineation of urban areas is relevant to considerations about the pandemic event, as the diffusion of an infection is clearly dependent on the spatial distribution of citizens at the national level and dynamics of social interactions within urban boundaries and across neighbouring cities. very recently, stier, berman, and bettencourt ( ) observed that growth rates of covid- in us cities revealed a power-law scaling relationship to city population. given that italy was among the most affected countries by the virus, delineation of urban areas in italy may acquire additional relevance in the present context and, most importantly, in the near future. very recently van raan ( ) studied the scaling of gross urban product (gup) versus population in denmark, germany and the fig. ; dots show the (p a , ) points for the three major disjoint geographical domains in italy. we compared to results for municipalities (black and red curves; = ± . . and = ± . . , respectively). in green the a-p fit for european cities, = ± . . . a comparison of the geographical distributions of the results, only for sicily, is in fig. . (for interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) fig. . pictorial representation of pairwise fusion of polygons, each represented by a grey dot. each colour represents a sample merger, among the few hundreds operated by algorithm . full circles correspond to the two original municipalities and empty squares to the polygon after the merger. the red, cerulean blue and orange groups show examples of mergers between a point above and a point below the linear fit (dashed line); the green and blue groups are example of both points below the fit. the brown, pink and cyan groups shows three of the many mergers undergone by the largest municipality (rome) which after the procedure would incorporate many neighbouring municipalities (see fig. ). (for interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) netherlands. like in this work, van raan ( ) considered urban areas, cities and municipalities. in particular, they distinguished urban and rural municipalities, finding substantially different scaling exponents, and concluded that urban regions consisting of a single municipality perform better than those including many municipalities. even if the scaling relation is different from the one considered here, i.e. gup versus p instead of a eff versus p, the two studies are clearly related, and the conclusions of van raan ( ) indirectly support the motivation and methods of the present work. in fact, both studies look at the performance of larger, coarser municipality boundaries with respect to smaller, finer boundaries, and both studies consider scaling relations, actually deviations from the empirical scaling relation, as performance indices. a sound assessment of area-population scaling for municipalities allowed to propose a criterion to merge municipalities in italy, driven scaling relations. the exercise of practical interest, in that official data in italy (istat, ) reveal that the number of municipalities changed by about units in the last thirty years; unofficial sources available on the www reveal that fusion of municipalities (comuni) started in . moreover, additional variation of such boundaries are planned for the near future. suppression or fusion of two or more municipalities into a new one were dictated by a number of different criteria, under the general aim of reducing the total number of administrative centers. we believe that the perspective from scaling laws proposed in this work can be useful to complete the criteria currently adopted for fusion of administrative boundaries, to obtain a comprehensive point of view. adoption of multiple criteria could avoid negative effects of individual criteria, when applied separately. for example, the only prescription of following an area-population scaling law could promote the practice of indiscriminate land use or urban sprawl, given that an administrative unit would be favoured if a large population corresponds to a large urban area. this could be avoided by the joint application of multiple criteria. the procedure for the fusion of administrative boundaries produced a new delineation consisting in units instead of the existing units. considering the empirical scaling relation of fig. as a metric for "performance" of each unit, the procedure reduced the total area of units classified as "less performing" from km to km (cf. table ), reduced the total area in intermediate classes from , km to , km , and increased the total area in the "most performing" class from , km to , km . we stress that we used the empirical a eff -p scaling law in the most straightforward way we could devise, to show the feasibility of the approach. an improved procedure could be implemented by means of additional criteria, for example applying considerations of economic table for results in terms of number of polygons and area in each class. maps are in laea projection, epsg: . the number of polygons and total area corresponding to the existing subdivision in municipalities in italy (old), and the proposed one (new). class corresponds to grey in fig. ; class , green; class , cyan; class , yellow; class , magenta; class , orange; class , cerulean blue; class , red; class , blue. number ( nature, or considering actual commuting flows in the commuting matrix described in section to single out candidate polygons for mergers. preliminary calculations aimed at checking the effects of simply relocating population from/to municipalities according to daily commuting flows showed to be of little relevance, as far as scaling laws are concerned (not shown here). the sll subdivision based on commuting flows, defined in italy by istat, provides a more sophisticated use of such information, independent on scaling considerations. fig. (a) shows a comparison of the a-p relations from our aggregation method and aggregations provided by sll and udc, highlighting rather substantial differences. regarding sll, fig. (a) clearly shows that the distribution of points in the (p a , ) plane is biased towards larger areas than the empirical scaling law, which was expected, given the different rationale and purpose of the sll subdivision. regarding udc, the differences are mainly due to the fact that both the considered existing methods do not take into account area and population simultaneously, the proposed delineation. the substantial difference is that the total population interested by udc amounts to , , citizens, while the corresponding figure for our new delineation is , , citizens (sll was delineated using different input data, so we do not report corresponding figures, here). this is clear indication that fusion of administrative boundaries performed in different ways may generate very different scenarios, population-wise. similar considerations holds for the current subdivision into municipal units, fig. (b) , where the new units involved , , citizens. a proper discussion should take into account both geographical boundaries and population data from , thought, while data in the figure correspond to population in . recently, an additional aggregation of municipalities was proposed by the italian civil protection department (dpc, ), going under the name of contesti territoriali (literally territorial contexts ct). this particular aggregation, while bearing a certain relationship with the abovementioned sll and udc, were developed for emergency planning and risk management. thus, the purpose of the aggregation proposed here is probably not directly comparable with the ct aggregation and was not explicitly considered in this work. a meaningful comparison with a proper discussion will be presented elsewhere. scaling laws for urban systems are deemed near-universal, because scaling of a specific indicator on city size slightly depends on geographical location and/or the criteria imposed for the very delineation of cities. nevertheless, once an empirical a-p law is established for a given country or otherwise homogeneous study area, it may be viewed as a general and robust measure of the "performance" of a city of a given size, in terms of expectations about its area (bettencourt, ; west, ) . we presented an analysis of italian urban areas in relation to existing administrative boundaries. we believe that the present work contributes to filling the existing gap in the literature, in which delineation of urban areas were not found for italy, allowing to distinguish the behaviour of different urban systems within europe. our results can be summarized in the following points: fig. . a eff -p relations for the individual administrative regions. in each panel, the three-letter code corresponds to table and fig. ; grey points and curves refer to existing municipalities' data and the corresponding fit (in), while coloured points and curves refer to the new delineation (out). the dotted curve is the a eff -p national fit, first shown in fig. as a red curve and referred to throughout this work. (for interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) • area a for italian municipalities scales sub linearly with population p, with a slope smaller than the slope obtained for italian and european cities from data available on the www, and within the range reported for world's cities by bettencourt ( ) . scaling is not obtained for the total area, though, but for the effective built-up (actually, impervious -or sealed) area a eff (fig. ); • we obtained "natural cities" using natural breaks selection of geographical zones built from the nodes of the national street network (figs. and ; (jiang & liu, ; jiang & miao, ) ). such a delineation of cities in italy provides very similar a-p relations with respect to the one valid for effective area of municipalities (fig. ); • a reduction of the number of administrative units, at municipality level, could be performed using the a eff -p scaling law as a general criterion for pairwise fusion of neighbouring polygons (fig. ); • iterative application of the merging procedure produced a new aggregation, containing , units, as compared to the existing , units ( figs. and ) . units are larger than the existing ones, but their population still follows the empirical a-p scaling law, at variance with existing aggregations of municipalities in italy (udc, sll and the current administrative boundaries; fig. ). we stress that a data-driven method for delineating cities such as the definition of natural cities adopted in this work, in conjunction with the many different methods considered by e.g., cottineau et al. ( ) , may contribute in finding a comprehensive and objective delineation method. the proposed real-world application of scaling laws is an example of the possibilities offered by such universal relations, suggesting their use in conjunction with other (expert, political, social, economic) criteria to delineate boundaries that simultaneously comply with, or are obtained from reasoned aggregation of, existing administrative subdivisions. one of the advantages of pursuing a path like the one outlined here is that it also represents a bottom-up approach, based on the ideas of emergent phenomena from self-organization, which may reveal more effective than top-down, centralized approaches to planning (barthélemy et al., ) . inclusion of general principles such an empirical a-p scaling law into the delineation of administrative boundaries goes into the direction of pursuing a comprehensive science of cities, envisaged by batty ( batty ( , . a science of cities which takes into account complex behaviour and emergent phenomena, which form the basis of scaling laws, may lead to cities and administrative boundaries which are more resilient against environmental, socioeconomic, and political issues (meerow, newell, & stults, ) , and hopefully against natural disasters (united nations, ) . we further highlight the importance of exploiting open data, including satellite and volunteered data which, in conjunction with modern open source gis software with powerful processing capabilities, and with a multidisciplinary approach, may be relevant for urban and administrative planning. the methods presented in this work can be readily extended to any country and in particular to the whole of europe, where data from the same sources used here is already available. algorithm . pseudo-code structure of the algorithm, implemented in grass gis, for pairwise fusion of municipality polygons driven by the empirical aeff -p scaling relation as in eq. ( ) and represented by the red curve if fig. . the flag chk is set to at the beginning of the procedure for all of the polygons. cities referred to in this pseudo-code are natural cities described in sections . and . . fig. . comparision of a eff -p relations with existing aggregations of municipalities in italy. (a) the existing (grey) and proposed (brown) units; we show only new mergers proposed in this work, and compared to alternative delineations, namely the "unione di comuni" (udc, blue) and the "sistemi locali del lavoro" (sll, cyan). for udc, we show the only aggregations differing for one or more units (as for the mergers), while we show all of the sll points, which have much larger areas than all of the other delineations. (b) grey and brown as in (a), compared to the actual new municipalities in italy, in (black points); population data were from for all the data sets. 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b: planning and design bivariate line-fitting methods for allometry a general model for the structure and allometry of plant vascular systems life's universal scaling laws cellular automata and fractal urban form: a cellular modelling approach to the evolution of urban land-use patterns gnuplot . : an interactive plotting program depicting urban boundaries from a mobility network of spatial interactions: a case study of great britain with geo-located twitter data human behavior and the principle of least effort i am indebted with the whole geomorphology group of cnr irpi, perugia, especially with dr. ivan marchesini for introducing me to the world of gis processing. i also thank dr. bin jiang, faculty of engineering and sustainable development, university of gävle, sweden, for thorough discussions about the definition of natural cities, and dr. luca fondacci, department of engineering, university of perugia, italy, for interesting discussions about urban planning. this paper also benefited from constructive comments of three anonymous reviewers. key: cord- -ywgoqlxj authors: ribeiro, haroldo v.; sunahara, andre s.; sutton, jack; perc, matjaž; hanley, quentin s. title: city size and the spreading of covid- in brazil date: - - journal: plos one doi: . /journal.pone. sha: doc_id: cord_uid: ywgoqlxj the current outbreak of the coronavirus disease (covid- ) is an unprecedented example of how fast an infectious disease can spread around the globe (especially in urban areas) and the enormous impact it causes on public health and socio-economic activities. despite the recent surge of investigations about different aspects of the covid- pandemic, we still know little about the effects of city size on the propagation of this disease in urban areas. here we investigate how the number of cases and deaths by covid- scale with the population of brazilian cities. our results indicate small towns are proportionally more affected by covid- during the initial spread of the disease, such that the cumulative numbers of cases and deaths per capita initially decrease with population size. however, during the long-term course of the pandemic, this urban advantage vanishes and large cities start to exhibit higher incidence of cases and deaths, such that every % rise in population is associated with a . % increase in the number of fatalities per capita after about four months since the first two daily deaths. we argue that these patterns may be related to the existence of proportionally more health infrastructure in the largest cities and a lower proportion of older adults in large urban areas. we also find the initial growth rate of cases and deaths to be higher in large cities; however, these growth rates tend to decrease in large cities and to increase in small ones over time. human activities have become increasingly concentrated in urban areas. a direct consequence of this worldwide urbanization process is that more people are living in cities than in rural regions since [ ] , and projections indicate that the world urban population could reach more than % by the end of this century [ ] . besides being increasingly urbanized, we live in an unprecedentedly connected, and highly mobile world with air passengers exceeding billion in [ ] . on the one hand, a highly connected and highly urbanized society brought us innovation, economic growth, more access to education and healthcare; on the other, it has also lead to pollution, environmental degradation, privacy concerns, more people living in substandard conditions, and suitable conditions for dissemination of infectious diseases over the globe. in particular, the emergence of infectious disease outbreaks has significantly increased over time, and the majority of these events are caused by pathogens originating in wildlife [ ] , which in turn has been associated with changes in environmental conditions and land use, agricultural practices, and the rise of large human population settlements [ ] . the ongoing outbreak of the novel coronavirus (sars-cov- ) seems to fit well the previous context as it was first identified in wuhan in december , an influential chinese city exceeding million inhabitants, and apparently originated from the recombination of bat and malayan pangolin coronaviruses [ ] . the coronavirus disease (covid- ) initially spread in mainland china but rapidly caused outbreaks in other countries, making the world health organization first declare a "public health emergency of international concern" in january , and in mid-march, the outbreak was reclassified as a pandemic. as of august , over . million cases of covid- have been confirmed in almost all countries, and the worldwide death toll exceeds thousand people [ ] . the covid- pandemic poses unprecedented health and economic threats to our society, and understanding its spreading patterns may find important factors for mitigating or controlling the outbreak. recent works have focused on modeling the initial spreading of covid- [ ] or the fatality curves [ ], projecting the outbreak peak and hospital utilization [ ] , understanding the effects of mobility [ ] , demography [ ] , travel restrictions [ ] , behavior change on the virus transmission [ ] , mitigation strategies [ ] , non-pharmaceutical interventions [ ] , networkbased strategies for social distancing [ ] , among many others. despite the increasing surge of scientific investigations on the subject, little attention has been paid to understanding the effects of city size on spreading patterns of cases and deaths by covid- in urban areas. the idea that size (as measured by population) affects different city indicators has been extensively studied and can be summarized by the urban scaling hypothesis [ ] [ ] [ ] [ ] . this theory states that urban indicators are non-linearly associated with city population such that socio-economic indicators tend to present increasing returns to scale [ , , ] , infrastructure indicators often display economy of scale [ , ] , and quantities related to individual needs usually scale linearly with city population [ , ] . urban scaling studies of health-related quantities have shown that the incidence and mortality of diseases are non-linearly related to the city population [ ] [ ] [ ] [ ] . despite the existence of several exceptions [ ] , noninfectious diseases (such as diabetes) are usually less prevalent in large cities, while infectious diseases (such as aids) are relatively more common in large urban areas. this different behavior is likely to reflect the fact that people living in large cities tend to have proportionally more contacts and a higher degree of social interactions than those living in small towns [ , ] . within this context, the recent work of stier, berman, and bettencourt [ ] has indicated that large cities in the united states experienced more pronounced growth rates of covid- cases during the first weeks after the introduction of the disease. similarly, cardoso and gonçalves [ ] found that the per capita contact rate of covid- increases with the size and density of cities in united states, brazil and germany. these findings have serious consequences for the evolution of covid- and suggest that large metropolises may become infection hubs with potentially higher and earlier peaks of infected people. investigating whether this behavior generalizes to other places and how different quantities such as the number of cases and deaths scale with city size are thus important elements for a better understanding of the spreading of covid- in urban areas. here we investigate how population size is associated with cases and deaths by covid- in brazilian cities. brazil is the sixth most populous country in the world, with over million people, of which more than % live in urban areas. while it is likely that the novel coronavirus was already circulating in brazil in early february [ ] , the first confirmed case in the country dates back to february , in the city of são paulo. between the first case and august , brazil has confirmed , , cases of covid- (second-largest number) spread out over . % of the , brazilian cities. this disease caused , deaths (second-largest number) with , cities reporting at least one casualty as of august . we start by briefly presenting our data set (see methods for details). our investigations rely on the daily reports published by the health offices of each of the brazilian federative units. these daily reports update the number of confirmed cases (y c ) and the number of deaths (y d ) caused by covid- in every brazilian city from february (date of the first case in brazil) to august (date of our last update). from these data, we create time series of the number of cases y c (t c ) for each city, where t c refers to the number of days since the first two daily cases reported in each city. similarly, we create time series of the number of deaths y d (t d ), where t d refers to the number of days since the first two daily deaths reported in each city. by doing so, we group all cities according to their stage of disease propagation (as measured by t c or t d ) to investigate the evolution of allometric relationships between total cases or deaths and city population. we have also considered different number of daily cases or deaths as the reference point, and our results are robust against different choices (from one to seven daily cases or daily deaths, see the number of cases is well described by a power-law function of the city population where β c is the so-called urban scaling exponent [ ] . similarly, fig b shows the association between the number of casualties and the city population on logarithmic scale (logy d versus logp) for different numbers of days since two daily deaths first reported (t d = , , and days). again, the results indicate that the number of deaths is approximated by a powerfunction of the city population where β d represents the urban scaling exponent for the number of deaths. the results of fig also show the adjusted allometric relationships (dashed lines) and the best fitting scaling exponents β c and β d (see methods for datails). these exponents exhibit an increasing trend with time so that β c and β d exceed one after some number of days after the first two daily cases or deaths. this dynamic behavior is better visualized in fig , where we depict β c and β d as a function of the number of days since the first two daily cases (t c ) or deaths (t d ). the scaling exponent for the number of cases β c is sub-linear (β c < ) during the first four months and appears to approach a super-linear plateau (β c > ) as the number of days t c further increases. the dynamic behavior of the scaling exponent for deaths β d is similar to β c ; however, β d appears to be approaching a plateau larger than the one observed for β c . the evolution of the scaling exponents for cases and deaths indicates that small cities are proportionally more affected by covid- during the first four months. however, this initial apparent advantage of living in large cities vanishes with time, and become a disadvantage after about four months. this is more evident by estimating the number of cases per capita from eq ( ), that is, y c /p � p β c − . similarly, we can estimate the number of deaths per capita from eq ( ), yielding y d /p � p β d − . thus, we expect the number of covid- cases or deaths per capita to decrease with the city population if β c < and β d < ; conversely, these per capita numbers are expected to increase with the city population if β c > and β d > . for instance, because β c � . and β d � . after days since the first two daily cases or deaths, the number of cases and deaths per capita decreases with population as y c /p � p − . and y c /p � p − . . at those particular values of t c and t d , an % rise in the population is associated with a � . % decrease in the incidence of covid- cases and � . % reduction in the incidence of deaths. in a concrete example for t c = t d = days, we expect a metropolis such as são paulo (with � million people) to have � % less cases and � % less deaths per capita than a medium-sized city such as maringá/pr (with � thousand people, � / of são paulo), which in turn is expected to have � % less cases and � % less deaths per capita than a small-sized city such as paranaíba/ms (with � thousand people, � / of maringá). however, both scaling exponents increase with time, such that this urban advantage vanishes and become a disadvantage during the long course of the pandemic. by considering our latest estimates for the scaling exponents, we find β c � . (t c = days) and β d � . (t d = days). thus, at these particular values of t c and t d , we expect the number of cases per capita to slightly increase with population (y c /p � p . ) and the number of fatalities per capita to increase with population as y d /p � p . . thus, for β d � . at t d = days, we expect a metropolis such as são paulo (� million people) to have � % more deaths per capita than maringá/pr (� thousand people), which in turn is expected to have � % more deaths per capita than paranaíba/ms (� thousand people). figs - in s appendix show that the scaling relations for number of cases and deaths per capita support the previous discussions. the latest estimates of β c found for cases of covid- are smaller than those reported for the h n pandemic in brazil (β c � . ) and hiv in brazil and united states (β c � . ) [ ] . similarly to what we observe for the cases of covid- , the allometric exponent for hiv cases in brazil was initially sub-linear during the s, became super-linear after the s, and started to approach a super-linear plateau after the s [ ] . however, the evolution of the allometry for hiv has been much slower than what we have observed for the covid- . another interesting point reported by rocha, thorson, and lambiotte [ ] is that the number of h n cases in brazil started to scale linearly with city population in (one year after the first outbreak). these authors also argue that this reduction in the scaling exponent possibly reflects a better response for the spread of h n after the pandemic outbreak. if the behavior observed in the h n pandemic generalizes (at least in part) for the current covid- pandemic, we would expect a decrease in values of β c in the future. the lastest estimates of β d for covid- deaths are larger than those reported for diabetes (β d � . ), heart attack (β d � ) and cerebrovascular accident (β d � ) in brazil after the s [ ] . conversely, scaling exponents related to disease mortality in brazil displayed a decreasing trend with time, and values as high as . were observed for diabetes in (β d � . ) and heart attack in (β d � . ) [ ] . the convergence of these exponents to linear or sub-linear regimes may reflect the increasing access to medical facilities in urban areas [ ] . based on currently available data (fig ) , it is hard to confidently assert whether the values of β c and β d will remain larger than one during the long-term course of the pandemic. however, the persistence of this behavior indicates large cities are likely to be more affected at the end of the covid- outbreak. part of this behavior may be due to large cities testing for covid- proportionally more than small ones. results for the united states indicate that more rural states have lower testing rates and detect disproportionately fewer cases of covid- [ ] . as brazilian cities are likely to suffer from this bias, we would expect a decrease in the scaling exponent β c after the observed increasing trend depending on the magnitude of this effect (that is, as small cities increase their testing capabilities, their number of cases tend to increase and bend the scaling law downwards). on the other hand, it is clearer that large cities were proportionately less affected during the initial months (since the first two daily cases or deaths) of the pandemic. we believe there are at least two possible explanations for this behavior. first, it may reflect an "increasing urban advantage" where the larger the city, the more access to medical facilities and so the chance of receiving more appropriate treatment against the coronavirus disease. a second cause can be associated with age demographic changes with the city population; specifically, a smaller proportion of older adults at high risk for severe illness and death from covid- leads to a reduced number of deaths per capita. another possibility is that the strategies and policy responses of large and small cities to covid- are different, which in turn may lead to different efficiency in containing the pandemic. these responses are highly heterogeneous at the national level [ , ] as well as among counties in the united states [ ] . among these three possibilities, we did not explore the possible effects of different city strategies against the covid- , but in light of the findings for the united states [ ] , this effect is likely to play an important role in the brazilian case and may deserve further investigation. to test for an increasing urban advantage for the treatment of covid- during the initial spread of the disease, we investigate the scaling relation between the number of hospital intensive care unit (icu) beds and city population. because critically ill patients frequently require mechanical ventilation [ , ] , the number of icu beds has proved to be crucial for the treatment of covid- . fig a shows the allometric relationship between the number of icu beds from private and public health systems (y icu , as of april ) and the population, where a super-linear relationship emerges with scaling exponent β icu � . . the super-linear scaling of icu beds indicates that large brazilian cities are better structured to deal with critically ill patients, which in turn may partially explain the reduction of deaths per capita with the city size during the initial three-four months since the first two daily deaths. it is worth noting that the brazilian public unified health system (sistema Ú nico de saúde-sus) is decentralized and composed of "health regions", contiguous groups of cities usually formed by a large city and its neighboring cities [ ] . cities within the same health region may share medical services, which may in turn partially explain the reduction of the structural advantages of large urban areas during the long-term course of the pandemic. we have also investigated how age demographic distribution changes with city population. estimates have shown that the case fatality rate of covid- is substantially higher in people aged more than years ( . % for those younger than years versus . % for those older than years [ ] ). thus, the age demographic of cities represents an important factor for the number of deaths caused by covid- . fig b and c show how the number of people older (p hr , the high-risk population) and younger (p lr , the low-risk population) than years change with the total population (p). we note that the high-risk population increases sub-linearly with city size with an exponent β hr � . , while the low-risk population scales linearly (β lr � ) with city size. this result shows that large cities have a lower prevalence of adults older than years, such that a % increase in city population is associated with a . % rise in the high-risk population. in a more concrete example, we expect a city with one million people to have proportionally � % fewer adults older than years when compared with a city of thousand inhabitants. thus, a low prevalence of elderly in large urban areas may also partially explain the initial reduction of the number of deaths per capita with the increase of city population. in addition to addressing the urban scaling of cases and deaths of covid- , we have investigated associations between the growth rates of cases and deaths and the city population (figs - in s appendix). as mentioned, the work of stier, berman, and bettencourt [ ] shows that the initial growth rates of covid- cases in metropolitan areas of the united states scale as a power-law function of the population with an exponent between . and . . by using our data and as detailed in methods, we have estimated the growth rates of cases (r c ) and deaths (r d ) for brazilian cities. in agreement with the united states case, our results also indicate that covid- cases initially grow faster in large cities (fig in s appendix) , such that r c � p b r c with b r c between � . and � . during the first three months (t c ≲ , fig in s appendix). we also found similar behavior for the growth rate in the number of deaths r d , where a power-law relation r d � p b r d is a reasonable description for the empirical data with a scaling exponent b r d between � . and � . during the first three months (t d ≲ , fig in s appendix). the growth rate depicts a more instantaneous picture of the covid- spreading process, and its association with size may change during the long-term evolution of the pandemic. these changes may reflect the different actions taken by each city to face the covid- pandemic and other particularities affecting the covid- spreading. for the spreading of covid- in the united states, heroy [ ] has reported that large cities appear to enter in an exponential spreading regime earlier than small ones. to better investigate these possibilities in our data, we have estimated the average relationship between the growth rate of cases (r c ) and deaths (r d ) and the city rank s (s = represents the largest city in data, s = the second-largest, and so on) at different periods. fig a shows the results for the growth rates in the number of cases (r c ). in agreement with the power-law association between r c and the city population (figs - in s appendix), we note that lower values of the city rank s are associated with higher growth rates r c in the initial days since the first two daily cases. however, as time goes by, the growth rate of cases starts to decrease in large cities (low-rank values) and to increase in small ones (high-rank values). this result appears to agree with the findings of heroy [ ] in the sense that there is a delay in the emergence of high growth rates of cases between large and small cities. fig b shows the same analysis for growth rate in the number of deaths r d . while we also observe a decrease in r d for large cities and increase for small ones, the differences in r d are less pronounced than in r c . these findings also emerge when investigating the scaling exponents associated with the growth rates of cases (b r c ) and deaths (b r d ). the results of fig in s appendix show that these exponents start to decrease around t c � t d � days and become negative in our latest estimates. it is worth remembering that the time t c (or t d ) is measured in days since the first two daily cases (or first two daily deaths) for each city; thus, the results of fig do not reflect delays in the emergence of the first case in each city. we have studied scaling relations for the number of covid- cases and deaths in brazilian cities. similarly to what happens for other diseases, we found the number of cases and deaths to be power-law related to the city population. during the initial three-four months since the first two daily cases or deaths, we found a sub-linear association between cases and deaths by covid- , meaning that the per capita numbers of cases and deaths tend to decrease with population in this initial stage of the pandemic. we believe this behavior can be partially explained by an "increasing urban advantage" where large cities have proportionally more icu beds than small ones. in addition, changes in age demography with city size show that large cities have proportionally less elderly people who are at high risk of developing severe illness and dying from covid- . this may also partially explain the initial reduction of fatalities per capita with the city population. in addition, we have argued that the strategies and policy responses of large and small cities to covid- may also be different and lead to different efficiency in containing the pandemic. however, we found that this "urban advantage" vanishes in the long-term course of the pandemic, such that the association between cases and deaths by covid- with population becomes super-linear in our latest estimates since the first two daily cases or deaths. thus, the persistence of this pattern indicates that large cities are expected to be proportionally more affected at the end of the covid- pandemic. this result is in line with the findings for other infectious diseases [ , ] and probably reflects the existence of a higher degree of interaction between people in large cities [ , ] . because social distancing is currently the only available measure to mitigate the impact of covid- , our results suggest that large cities may require more severe degrees of social distancing policies. in agreement with the results for metropolitan areas in the united states [ ] , we have found that large cities usually display higher growth rates in the number of cases during the initial spread of the covid- . however, our results also show that these growth rates tend to decrease in large cities and to increase in small ones in the long-term course of the pandemic. this behavior suggests the existence of a delay in the emergence of high growth rates between large and small cities. similar behavior was also found in the united states [ ] , where large cities appear to enter an exponential growth regime earlier than small towns. the existence of this delay suggests that the initial slow-spreading pace of the covid- in small cities is likely to be a transient behavior. together with the recent findings of stier-berman-bettencourt [ ] and heroy [ ] for the united states, as well as those of cardoso and gonçalves [ ] for united states, brazil and germany, our results suggest that social distancing policies and other actions against the pandemic should take into account the non-linear effects of city size on the spreading of the covid- . the primary data set used in this work was collected from the brasil.io api [ ] . this api retrieves information from covid- daily reports published by the health offices of each of the brazilian federations ( states and one federation district) and makes it freely available. this data set comprises information about the cumulative number of cases and deaths of covid- from february (date of the first case in brazil) until august (date of our last update) for all brazilian cities reporting at least one case of covid- . the brasil.io api also provides population data of brazilian cities, which in turn relies on population estimates for the year released by the brazilian institute of geography and statistics (ibge). there is a total of , brazilian cities with at least one reported case of covid- on august , corresponding to . % of the country's total number of cities. in addition, , cities suffered casualties from this disease, representing . % of the total. to ensure that our estimates rely on at least cities, we consider a suitable upper threshold for the time series length (fig in s appendix) . the data about age demographics refer to the latest brazilian census that took place in , while the data about the number of icu beds are from april . these two data sets are maintained and made freely available by the department of informatics of the brazilian public health system (datasus) [ ] . urban scaling [ ] usually refers to a power-law association between a city property y and the city population p, and it is expressed by where y is a constant and β is the urban scaling exponent. eq ( ) can be linearized by taking the logarithmic on both sides, that is, where log y and log p are the dependent and independent variables of the corresponding linear relationship between log y and log p. we have estimated the power-law exponents in eq ( ) by using the probabilistic approach of leitão et al. [ ] . specifically, we have found the probabilistic model with lognormal fluctuations and where the fluctuations in log y are independent of p to be the best description of our data in the majority of scaling laws. thus, we assume these lognomal fluctuations in all adjusting procedures in order to estimate the values of β. it is worth mentioning that this maximum-likelihood estimate for scaling exponents is analogous to the one obtained via usual least-squares with the log-transformed variables (log y versus log p). let us consider that x t (t = , . . ., n) represents the cumulative number of cases (y c ) or the cumulative number of deaths (y d ) for covid- in a given city at time t (number of days since first case t c or death t d ). the logarithmic growth rate r t at time t is defined as where τ is a time delay. if we assume the numbers of cases or deaths to initially increase exponentially (x t � e rt , where r is the exponential growth rate), r t represents an estimate for the growth rate of this initial exponential behavior (r). we have estimated r t for the number of cases (r c ) and deaths (r d ) up to values of t c and t d ensuring a sample size of at least cities for the allometric relations between these growth rates and the city population (fig in s appendix). all results in the main text were obtained for τ = but our discussion is robust for τ between and days (figs - in s appendix). supporting information s appendix. supplementary figs ( - ) world urbanization prospects: urban population (% of total) global urbanization projections for the shared socioeconomic pathways international civil aviation organization, civil aviation statistics of the world and icao staff estimates global trends in emerging infectious diseases origins of major human infectious diseases isolation of sars-cov- -related coronavirus from malayan pangolins projecting hospital utilization during the covid- outbreaks in the united states spread and dynamics of the covid- epidemic in italy: effects of emergency containment measures demographic science aids in understanding the spread and fatality rates of covid- the effect of travel restrictions on the spread of the novel coronavirus (covid- ) outbreak applying principles of behaviour change to reduce sars-cov- transmission the impact of covid- and strategies for mitigation and suppression in low-and middle-income countries estimating the effects of non-pharmaceutical interventions on covid- in europe social network-based distancing strategies to flatten the covid- curve in a post-lockdown world growth, innovation, scaling, and the pace of life in cities the origins of scaling in cities the new science of cities scale: the universal laws of growth, innovation, sustainability, and the pace of life in organisms, cities, economies, and companies scaling and universality in urban economic diversification computational socioeconomics influenza and pneumonia mortality in large cities in the united states in years surrounding the pandemic growth patterns and scaling laws governing aids epidemic in brazilian cities statistical signs of social influence on suicides the non-linear health consequences of living in larger cities the scaling of human interactions with city size covid- attack rate increases with city size urban scaling of covid- epidemics tracking the onset date of the community spread of sars-cov- in western countries a commentary on rural-urban disparities in covid- testing rates per , and risk factors. the journal of rural health the effect of large-scale anti-contagion policies on the covid- pandemic quantifying policy responses to a global emergency: insights from the covid- pandemic creatures of the state? metropolitan counties compensated for state inaction in initial us response to covid- pandemic. mansueto institute for urban innovation research paper critical care utilization for the covid- outbreak in lombardy, italy: early experience and forecast during an emergency response covid- : a novel coronavirus and a novel challenge for critical care brazil's unified health system: the first years and prospects for the future estimates of the severity of coronavirus disease : a model-based analysis. the lancet infectious diseases metropolitan-scale covid- outbreaks: how similar are they? boletins informativos e casos do coronavírus por município por dia public healthcare system (sus), department of data processing (datasus) is this scaling nonlinear the authors have declared that no competing interests exist. key: cord- - d x j authors: nijman, jan; wei, yehua dennis title: urban inequalities in the st century economy date: - - journal: appl geogr doi: . /j.apgeog. . sha: doc_id: cord_uid: d x j in the last decade or so, inequality studies have assumed renewed prominence across the social sciences. in this introduction to a special issue of applied geography, we set out to articulate the importance of urban spatial context in broader present-day inequality debates. we argue that the information-based economy is emphatically urban-based and that it has forged new spatial inequalities in and between cities and among urban populations. income gaps have widened, inter-city disparities have grown, suburbs have been re-sorted into a wide array on the basis of class and race or ethnicity, and many central cities have assumed a renewed importance within metropolitan areas. we argue that attention to urban spatial dimensions at various scales is critical to understanding current inequality trends, from intra-urban to regional and global scales. contributions to this special issue from north america, europe, south america, and china suggest that deepening urban inequalities are pervasive across the globe. inequality has long been an important theme in the social sciences, and it has acquired renewed prominence in the last couple of decades. this is expressed, for example, in the recent establishment of special research centers such as ucla's institute on inequality and democracy, lse's international inequality institute, stanford's center on poverty and inequality, and the university of amsterdam centre for inequality studies. it is also apparent, of course, in the literature. the work by thomas piketty ( ), particularly, drew much attention and it was emblematic of a wider trend across the academy (e.g., stiglitz, ) and in public debates and popular media (e.g., the economist, ) . the debates have focused mostly on national trends and, insofar they have international reach, pertain to aggregate national data sources. in such studies, inequality trends are often related to issues of economic globalization, international migration, and neoliberal government policies. many studies rely exclusively on income data even though it is widely acknowledged that inequality is a multifaceted phenomenon with economic, social, environmental, and political dimensions. variations across class, race, ethnicity, age, gender, or citizenship status are also often considered at the national level. at the same time, urban studies scholars and geographers have long attended to questions of inequality (e.g., harvey, ) and have done so at a finer spatial scale, as expressed in studies of residential segregation and neighborhood development (see galster & sharkey, ; hamnett, ) . in some respects, this tradition goes back as far as the urban ecology approach of the chicago school. there appears, however, a significant disconnect with the more general social science literature and much of that is probably due to different scales of analysis and the attention (or lack thereof) to the role of space in the creation or maintenance of inequality. in this article, we set out to articulate the importance of the urban context in broader present-day inequality debates. in part, this is simply a reflection of rapid and ongoing urbanization worldwide, where social questions are increasingly urban questions (brenner & schmid, ; wang, he, liu, zhuang, & hong, ) . it is also, we argue, related to the worldwide emergence of new modes of production in the last few decades (digital, information-based, consumer oriented) that signal an unprecedented urbanization of the world economy, what scott ( ) refers to as the "third wave". finally, we argue that this new, largely urban-based, economy is accompanied by new and deepening inequalities across multiple dimensions. our argumentation is based on a broad overview of the literature, in part from a comparative perspective (nijman, a) , and with special attention to the other articles in this special journal issue. our main point is that, if we want to understand overall inequality trends in the st century and the policies needed to confront them, it is imperative to consider their urban contexts. the rest of this paper is structured as follows. in section , we provide an outline of the goals and organization of this special issue and we give a brief overview of the included articles. section sets out a concise theoretical argument that focuses on the urban impacts of the new st century post-industrial economy and on the new inequalities that are inherent to this economy and that play out at different scales. section provides a concise discussion on inter-urban and regional dynamics of inequality and in section - the focus shifts to a more elaborate discussion of intra-urban inequalities. the paper ends with section , a series of conclusions and final remarks. the collection of papers in this special issue resulted from similarly themed sessions at two conferences in : the comparative urbanism conference of the newly founded urban studies institute at georgia state university in march , and the annual meeting of the american association of geographers in april. additional papers were solicited through a call from applied geography. the goal was to bring together a set of papers on present-day urban inequalities with different (global) geographic foci, at various scales, and with attention to different inequality dimensions. this special issue is intended to broaden the understanding of the spatial and temporal aspects of urbanizationincluding their patterns, processes, and intertwinement with equitable and sustainable development. on the basis of theoretically guided empirical research, it examines spatial and temporal dimensions of socio-economic inequality, analyzes the significance of the urban context of inequalities, and provides insights for urban planners and administrators to balance efficiency, equity, and environment. its point of departure comprises the following broad research questions: � what are the trends and nature of inequality in the city/cities in question? what are the temporal and spatial dynamics? � what is the explanation for these inequality trends and, specifically, how do they relate to (a) urbanization trends, (b) shifting modes of production and changing urban political economies, and (c) local/ national urban policies? � how do economic inequalities interact with disparaties in terms of race, gender, age, ethnicity, and migration-status? � how is urban inequality manifested in residential segregation, spatial mismatch, housing inequality, digital divide, environmental injustice, and in general spatial inequality? � what are the theoretical and policy implications of the research? among the geographic foci of the resulting set of nine papers are cities in the united states, china, europe, and south america; they combine analyses of inequalities at regional/inter-urban and intra-urban scales; and they cover a range of inequality dimensions including questions of residential segregation, commuting, food access, health, housing disparities, job access, economic vitality, and demography. the current issue stands apart from previous collections on inequality in terms of its global comparative approach, attention to variation in scale, and its focus on the role of the new urban economy. all the papers included in this special issue were reviewed following the standard review protocol and quality standards of applied geography. while social disparities are always culturally and historically mediated and as such vary from one time or place to the next, contemporary inequalities can also be argued to be fundamentally conditioned by prevailing modes of production and associated labor relationsand these tend to operate at much wider, even global, scales. proper understanding of current urban inequalities requires a fundamental understanding of such recent shifts in the nature of production and of the spatial ramifications of these shifts, particularly at the urban scale. as we argue below, the new economy has propelled urban inequalities in three ways: ( ) greater bifurcation of the workforce and deepening income inequalities; ( ) increasing inter-urban inequalities (growth vs. shrinkage); and ( ) revival of central cities and urban centers that have become increasingly exclusionary, along with increased 'sorting' and inequalities between different suburban areas. it is widely agreed that the rise and (relative) decline of manufacturing were highly significant to processes of urbanization. there is no need here for a general review but it is worth noting that the manufacturing era generally witnessed urban growth and expansion of the (lower) middle classes. the later decline of manufacturing in north america and europe since the s was directly related to the ensuing urban crisis, one aspect of which involved the shrinking of the working middle classes. for the purpose of this paper, we are particularly interested in what happened since the s and in more recent years. the share of the u.s. workforce in manufacturing dropped steadily, from % in to % in , and it never returned to previous levels. the recovery of urban growth since around was in essence based on the emergence of a new economy; a new mode of production that was, even more than during the industrial age, emphatically situated in urban areas. instead of manufactured goods, the new economy revolves around information products and was propelled by the digital revolution. it involves mainly finance and professional and business services (accounting, insurance, advertising, consulting, marketing), cultural industries (sassen, ; scott, ) , and, in some urban areas, high-tech industries (e.g., silicon valley, the texas corridor, the nc research triangle, etc.). new corporate and job growth was accompanied with population increases, an expanding tax base, increased infrastructure spending, construction, etc. a look at the biggest companies based in new york is illustrative. according to fortune.com, in the ten biggest (publicly traded) companies in terms of revenues headquartered in new york were verizon, j.p. morgan chase, citigroup, metlife, pfizer, aig, new york life insurance, morgan stanley, goldman sachs, and tiaa. half of them are in finance, three in insurance, and the other two in information technology and pharmacology. even in cities where more traditional companies dominate (such as manufacturing and foods, as in chicago or pittsburgh), most jobs in these companies in the city are filled with what robert reich ( ) calls 'symbolic analysts', highly educated and highly paid white collar workers. the urban revival under the new economy has been very uneven: for every new york, there are dozens of smaller cities struggling to latch on to the information economy; for every silicon valley, there are dozens of urban regions lacking hi-tech industrial development. for some of the cities that did not follow the example of new york, deindustrialization had lasting and deeply erosive effects; the transition to an urban information economy, high-tech production and especially consumption never quite arrived and the return to growth never happened. in , one in ten u.s. cities had shrinking populations and the experience is not unique to the united states. for example, one-third of germany's cities are losing population; the same is happening in varying degrees across europe and, notably, also in japan and south korea. in some countries, the problem is compounded by low birth rates and slow or even negative overall population growth. within cities, the ramifications for inequality have been just as significant. while cities such as new york and others revived against the backdrop of this dynamic new economy, the benefits did not accrue equally across the urban population. in fact, the new economy has only deepened the inequality that crystallized during the period of deindustrialization and urban decline. professional workers in the new economy tend to be highly educated, highly skilled, and highly paid. the service workers in that same economy, from retail personnel to clerical staff to hospitality workers, tend to be low-skilled and low-paid. accordingly, the new urban economy is characterized by a bi-modal income distribution, a bifurcated workforce, and a polarized social structure (e. g., sassen, ) . to keep with the example of new york: in , the top % of income earners took % of all income while the bottom half had to make do with % (nyibo, ). nationally, in terms of wealth (of greater significance than income to the truly advantaged), in the top . % of the u.s. population had more than doubled its wealth since and controlled as much as the bottom % (saez & zucman., ) . this trend of increasing inequality is perhaps most extreme in the u. s. but it appears evident in cities around the world where the new economy has emerged, including europe, china, and india (various papers, this volume; nijman, ; b) . the chinese case, in particular, demands some discussion for our purpose. chinese cities today are the scene of a conjunction of manufacturing, deindustrialization, and the new economy all at once. one could say that successive developments that shaped u.s. cities over three or four decades, are compressed in time and space across chinese cities today (nijman, ) . china has already experienced some deindustrialization and there will be more to comebut deindustrialization will not be as massive or disruptive as in the u.s. presently, manufacturing constitutes about % of all employment and has been steady over the last decade or so (levinson, ) . productivity continues on an upward trajectory: the increase in value added through manufacturing from to was % (adjusted for inflation), compared to only % for the u.s. (levinson, ) . nonetheless, china is (and has been) subject to selective deindustrializationparticularly so in the older industries of the country's northeast but also, more recently, in major cities such as shanghai or beijing. events in beijing in recent years underscore this selective deindustrialization and economic transition. the authorities have been demolishing large dense residential areas in beijing that were populated by rural migrants without hukou (household registration system). while the government cited reasons such as safety hazards and recent deadly fires in several neighborhoods, observers pointed to a declining need for lowskilled employment in the major cities and an aggressive government policy to make room for more highly educated workers in the new economy (buckley, ) . hence, notwithstanding the relative overall stability of manufacturing, it is clear that china's economy is in transition and that the new economy has been growing in importance. according to a recent oecd report, between and , the contribution of manufacturing to gdp decreased steadily from to % and dropped below the contribution of services for the first time in (oecd, ). to be sure, the urban information economy and its high-tech accompaniments are already there. the economy in the last two decades has been diversifying, and investments in it and high-tech sectors are substantial and growing. the total valuation of china's 'unicorns' (startup companies valued at $ billion or more) in was roughly on a par with that of the u.s., a powerful indicator of the presence of a mature and dynamic new economy (mckinsey, ) . the rapid emergence of the new urban economy, where incomes tend to be higher, often much higher, than in manufacturing or lowskilled services, has contributed to growing inequality and this will likely increase further in the years to come (particularly in a generational sense, with higher incomes among young professionals). it is a different inequality, however, from that which characterized u.s. cities in recent decades: if in the u.s. the middle class dwindled due to deindustrialization, in china it did not. rather, the growing inequality in chinese cities is related to the introduction of a new class of (very) high income earners in the new economy. in many cities around the world, the shift towards an informationbased mode of production has in recent years been accompanied by two interrelated trends that have contributed to a revival of central cities and, especially in the u.s., a re-sorting of suburbia. first, the logic of agglomeration in the new urban economy has shifted to an emphasis on knowledge transfers and networking in a high density and high circulation environmentthe city as "the office," especially for growing numbers of self-employed and freelancers (carlino, ; kloosterman, ; scott, ) . the new economy places a premium on networking, both virtually and in real space, and on the importance of a 'feel' for what is trending, especially in the cognitive-cultural sectors. notions of the 'gig economy' and the 'sharing/platform economy' have rapidly found a way into popular discourses but their significance is not entirely clear; in terms of the actual (relative) numbers of workers, types of workers, incomes, and vulnerabilities (graham, hjorth, & ledonvirta, ; davidson & infranca, ; shambaugh, nunn, & bauer, ) . we do know that these segments of the new economy are disproportionately located in cities. the second trend pertains to the rise of cities as sites of consumption (jayne, ) . the sharp decline in manufacturing employment and, eventually, its replacement with new employment in high tech and/or information activities, resulted in growing inequality and the formation of a class of high income earners who either work and live in the city or who work further out but choose to live in the city for its amenities. this means that cities and city centers have become preeminent sites of consumption, consumer services, and amenities. as glaeser, kolko, and saiz ( ) observed at the turn of the century: "the future of cities depends on the ability … to provide attractive places for increasingly rich workers." the combined effect of these trends has been what ehrenhalt ( ) termed "the great inversion": the movement of corporate activity, retail, restaurants, entertainment, people, back into the city, drawn to 'urban chic' and amenities. these new urbanites are relatively young, tend to be highly educated, have relatively high incomes, and, at least in the u.s., are predominantly white. the idea of inversion rests, of course, on the prior history of suburbanization (and white flight) and urban decay that was especially characteristic of us cities. it does not mean that suburbs have been growing any less quickly (kolko, ) , but it does imply central-city revival and renewed growth. in the u.s., especially, the "return" to the city tends to exclude minorities (and lower income earners) and, as such, is causing a racial (and political) makeover of central cities. at the same time, certain suburbs witness the departure of young and highly educated people to the central city. those suburbs may at the same time witness an influx of foreign migrants or the very people who are being displaced from the center. gentrification has been prominent feature of central city revival. many older inhabitants have had to find more affordable housing in the suburbs and, as a result, suburbia has become increasingly sorted on the basis of socio-economic status and race (nijman, ; nijman & clery, ) . central cities have now also become places of consumption for lower income classes living away from (or having been displaced from) the central city. to them, 'going to the city' is not about going to work, but about leisure and consumption. in sum, the new economy, for all its vigor, growth and contributions to aggregate prosperity, has forged new spatial inequalities in and between cities and among urban populations. the income gap has widened, inter-city disparities have grown, suburbs have been re-sorted into a wide array on the basis of class and race, and perhaps most striking of all, for many working in the new economy, aspirations of urban living have supplanted the old dream of a home in suburbia. the uli ( , p. ), addressing an audience mainly of developers and realtors, refers to the "willingness" of metropolitan populations, whether in central cities or suburbs, "to pay a premium for more urban living," adding that it has "become somewhat of a luxury good that many households will not be able to afford." scholars have heatedly debated the trends of spatial inequality, especially regional inequality, and sources or mechanisms for decades, even centuries (wei, (wei, , . convergence and divergence are two mainstream schools of thought concerning income and spatial inequality. the convergence school holds that regional inequality arises during the early stages of development, and declines as the economy matures, largely determined by free mobility of capital and labor. on the other hand, the divergence school argues that regional inequality tends to be maintained and even intensified; agglomeration and capital accumulation tend to reinforce spatial inequality and uneven development. barro and salaimartin ( ) emphasizes beta-convergence (i.e., poorer regions tend to grow faster than richer regions), and club convergence among regions with similar development conditions. these studies have revitalized the research on regional inequality, but have also drawn criticism (martin & sunley, ; wei & ye, ). notions of agglomeration, cumulative causation, and increasing returns to scale have also increasingly drawn the attention of scholars who tend to be concerned with the negative effects of globalization, including the rise of spatial inequality (ezcurra & rodríguez-pose, ; wei, ) . the recent global financial crisis has further intensified the debates on income inequality, especially the trend of polarization and the decline of intergenerational mobility (beyer & stemmer, ; ewing, hamidi, grace, & wei, ; ezcurra & rodríguez-pose, ) . geographers have paid special attention to the spatiality of inequality, employing concepts of scale, space, place, network, location, and mobility (wei, ) . the urban economy is the most dynamic component of cities, and analyzing economic inequality is important to understanding urban inequality and addressing urban problems. economic inequality is an essential component of urban inequality. geographers are keen to provide a multi-perspective view of geographical phenomena. scale is essential to the understanding of the spatiality of inequality (wei, (wei, , . inequality among cities, or interurban inequality, has long been studied and is closely linked to the study of urban systems. for example, the study of city size distribution can be considered as a study of uneven population distribution across cities (iyer, ) . interurban inequality also contributes greatly to regional inequality, since the concentration of resources in and the attractiveness of major cities are important sources of factor mobility and regional inequality (black, natali, & skinner, ; zhong & wei, ) . intra-urban economic inequality has drawn particular attention in studies of north american cities. intra-urban inequality is fundamental to multidimensional urban inequality and often strengthens the degree of other dimensions of urban inequality. many dimensions of urban inequality, such as spatial mismatch, residential segregation, and food deserts, are closely interwined. urban inequality is embedded in the broad socio-economic context, especially the process of globalization and technological change. globalization has directly changed the pattern of urban inequality, and the concept of global cities is based on the intensification of intraurban inequality in global command and control centers arising from globalization (friedmann, ; sassen, ) . indeed, external forces have long been argued as critical forces of spatial polarization and urban inequality in developing countries (kasarda & crenshaw, ) . neoliberalism raises concerns about growing inequality; shi and dorling ( ) , for example, uncover diverse patterns of inequality resulting from neoliberalism in beijing and london, and call for considering local conditions (for example, speed of change) in global urban studies. foreign direct investment (fdi) tends to prefer cities with well developed infrastructure, covenient access to political power, substantial integration with the global economy, and advanced social-economic conditions, which result in an increase of urban primacy and spatial polarization (huang & wei, ) . fdi also agglomerates within cities, leading to urban spatial polarization and segregation (grant & nijman, , pp. - ; huang & wei, ; wu, ) . closely related to fdi is foreign trade, which also has greatly influenced urban inequality. trade liberalization tends to worsen the core-periphery gap, and more trade-oriented countries tend to exhibit more regional inequality (rodríguez-pose, ) . zhu, yu, and he ( ) further discover that export upgrading mainly benefits urban areas, and the concentration of exports in urban areas tends to lead to more severe urban-rural inequality. technology is a major agent of globalization and has been regarded as a main source of urban growth in both developed and developing countries (liefner & wei, ; malecki, ) . however, the development and the increasing importance of technology may contribute to urban inequality as well. digital inequality has arisen as a huge concern as rapid technological change further centralizes talents, capital and innovation, and leaves many places behind. interregional knowledge spillovers only happen when the technological gap is not too wide (nocco, ) , hence technological advances may lead to greater regional inequality and polarization. technology also results in other dimensions of urban inequality, such as residential segregation, which should be carefully addressed by urban planners and policy makers (florida & mellander, ) . income inequality has been increasingly exacebrated by inequality in wealth, especially the appreciation of property values (goodman, ) . skyrocketing housing prices and the problem of housing affordability have become challenging issues globally. housing is an essential need for urban residents, and the housing market is intertwined with urban inequality in multiple ways. in the housing market, buyers have different preferences. preferences, and even discrimination, of different groups combined with differences in income, education, age, and race result in residential segregation (clark, ; ihlanfeldt & scafidi, ) , such differentials are also reflected in the existence of housing submarkets . the segregation of housing markets and the problem of housing affordability have been regarded as drivers of urban inequality (baker, bentley, lester, & beer, ; wei & ewing, ) . orthodox studies of housing price inequality are mainly based on a hedonic model, considering the effects of housing attributes, location, and, in later studies, neighborhood effects. location often refers to access to important geographical features and services, such as transportation facilities, cbds, and shopping centers. nevertheless, such models are often simplified, and recent studies have attempted to expand the determinants by including urban amenities and spatial structure (li, wei, & wu, a) . housing prices are also often cyclical, and the recent global financial crisis was largely caused by the housing crisis. li and wei ( ) study the resilience of housing prices in relation to the financial crisis and find that while the influence of amenities is important, neighborhood conditions also contribute greatly to the fluctuation of housing prices. more expensie houses usually have a desirable living environment and better accessibility to superior urban amenities, while "negative amenities", which are related to potential adverse effects on people including safety and health hazards (li, wei, yu, & tian, ) , usually decrease housing prices (bin & landry, ) . consequently, as richer people are able to buy "better houses" and poorer people cannot, the housing market results in an evolutionary inequality and residential segregation. most neighborhood-beneficial amenities increase local housing prices, resulting in the concentration and segregation of housing affordability (li et al., ) . lack of affordable housing has resulted in homeless people and slums, a terrible form of urban living (shinn & gillespie, ) . inequality in the housing market and residential segregation may limit the posssiblity of upward mobility (ewing et al., ) . housing inequality has also risen in chinese cities, and service amenities, especially education and subways, have become even more important factors affecting housing prices than in cities in the developed countries yuan, wu, wei, & wang, ) . as an alternative way to live in cities, the rental housing market is particularly important to migrant workers and low-income families. given the profit-driven nature of real estate developers, cheap rental houses are often lacking in the market. rental housing is also related to urban inequality. discrimination may exist, as the dwelling owners may select renters (ahmed & hammarstedt, ) . similar to the housing market, the accessibility to various resources also plays a vital role in rental prices, which results in an uneven spatial pattern of rents (li, wei, wu, & tian, b) . more importantly, renters may not receive the same rights as homeowners. for example, renters in china may not have access to public schools and public housing because of the hukou system (li, wei, yu, tian, ) . rents in large cities tend to be high compared to income, especially in job-concentrated downtown areas, which may result in a new form of housing poverty (sato, ) . li and wei ( ) explore the patterns of rent stress in china and identify several critical determinants including policy, economic conditions, urban hierarchy, as well as north-south and rustbelt-sunbelt divisions (liu et al., ) . affordable housing programs also are critically linked to urban poverty and inequality. many affordable housing programs have "failed" to some degree (albright, derickson, & massey, ; nguyen, basolo, & tiwari, ; zou, ) . these programs tend to cover the people who are more vulnerable (huang, ) . however, in the u.s., illegal immigrants are suffering more from housing affordability problems (mcconnell, ) , but the lack of legal status may prevent them from getting housing assistance (mccarty & siskin, ) . there are similar situations in china, as many policies are only available to registered residents (local urban hukou holders), and government policies provide registered residents better accessibility, or lower barriers to get the benefits than migrants (huang, ) . furthermore, these programs may not be welcomed by nearby communities because of "not in my back yard" (nimby) effects (nguyen et al., ) . combined with the fact that people relying on affordable housing usually have lower income and mobility, these people may get stuck in areas with less development, which can finally constrain their upward mobility (verdugo, ). residential segregation has long been a subject of inquiry by urban geographers and sociologists (fossett & waren, ; , and its related demographic dynamics may complicate patterns of neighborhood change and segregation (wyly, ) . residential segregation is linked to multiple dimensions of inequality including inadequate education, poor health, and lack of jobs (li, campbell, & fernandez, ; wei, xiao, simon, liu, & ni, ; williams & collins, ) . segregation is a significant societal concern and is central to the study of urban inequality in cities in the united states, and increasingly in europe and developing countries as well. musterd, marcinczak, van ham, and tammaru ( ) reported an alarming increase in socioeconomic segregation between poor and rich in european capital cities. residential segregation is in a significant concern in urban inequality . the spatial concentration of deprivation results in lower social position and social mobility since the residents do not have stable or productive social networking to gain access to resources (bolt, van kempen, & van ham, ) . these disadvantages further lead to serious social problems such as dropping out of school, limited job accessibility, and social exclusion (massey, condran, & denton, ) . the study of residential segregation can be traced back to the s. using the terms from biology such as invasion, succession, and dominance, the chicago school described the dynamics of residental flows and neighborhood composition using terms borrowed from ecology . in this view, with the "invasion" of blacks, whites will move out to avoid unhappiness or conflict, and their houses will be mostly occupied by blacks. two perspectives dominate the interpretation of residential segregation. the racial preference perspective holds that discrimination persists within different groups, and people are sensitive to local population-composition changes, and when they feel the mixture has exceeded their tolerance, they will move out (bolt et al., ) . the other perspective highlights exclusion; immigrants lack the means to buy a house in a neighborhood with high socioeconomic status, and face institutional barriers erected by mortgage providers, real estate agencies, and local and national institutions (bolt et al., ) . residential segregation may increase or decrease, and it is driven by different processes in different cities (beiley, van gent, & mustered, ) . several types of residential segregation have been identified. the most studied one is racial residential segregation. many studies of racial residential segregation, especially in the u.s., are focused on the segregation of african americans, which is still at a high level and is a comprehensive result of economic factors and preferences (clark, ) . other studies also find that racial residential segregation varies among different ethnic backgrounds. for example, mexican immigrants in the u.s. generally fit the trend described by the spatial assimilation model (brown, ) . chinese immigrants, however, are more likely to fit the cultural preference model, although some of them are not pursuing residential assimilation, as chinese immigrants still prefer to live among other chinese (yu & myers, ) . income segregation is also an important topic, and has been increasing over time as well (galster & sharkey, ) . the economic condition of a household is naturally linked to housing choices and neighborhood assets because people need to pay more for amenities (li et al., . income segregation results in severe problems when local governments highly depend on taxes to provide social welfare, public goods, and infrastructure (ross, houle, dunn, & aye, ). the rich may "self-segregate" thanks to their enhanced residential mobility (reardon & bischoff, ; watson, ) . scholars have also begun to relate income segregation to other dimensions of urban inequality, such as spatial mismatch. for example, haddad ( ) uncovers the positive and intensifying relationship between income segregation and commuting time, which significantly affects urban poor. in addition, florida and mellander ( ) find that economic segregation impacts local innovation and economic performance, which may intensify regional inequality. partly because of income segregation, skill segregation is another type of residential segregation. economic development requires complementarity among high-and low-skillworkers. the polarization of wages in labor markets between high-and low-skilled labor may result in skill-based residential segregation. such segregation has negative effects on skill-based or knowledge-based urban growth. except for the typical results of residential segregation such as limited access to job information and networks and low upward mobility, the isolation of low-skilled workers also decreases the productivity of high-skilled workers because they also have low accessibility to the services they demand (li et al., ) . residential segregation is also highly sensitive to local demographical changes (cloutier, ) , and migration. wessel, turner, and nordvik ( ) identified the importance of migration and immigration in spatial integration and segregation. focusing on foreign-born immigrants, bagchi-sen, rogerson, seymour, and franklin ( ) highlight their role in averting population loss in the u.s., and discover that major cities are usually the destinations of foreign-born; the authors provide insights concerning a number of urban issues including new forms of segregation, immigrant inequality, shrinking cities, and love-hate relationships between residents and migrants. besides economic, housing and residential inequalities, urban inequality is multi-dimensional and highly complex. it is all aspects of the cities, such as education inequality, transportation inequity, spatial mismatch, environmental injustice, the digital divide, food deserts, and unequal access to government services. different dimensions of urban inequality are intertwined and interactive and related to geographical factors, including urban space, scale, zoning, environment, and accessibility to various urban facilities. for example, education inequality is partly the consequence of residential segregation and housing affordability, as well-off people are able to pay more for better education resources . concentrating on accessibility of job opportunities, "spatial mismatch" has become a major concern in the metropolitan areas in the united states (chapple, ) . two kinds of spatial mismatch are highlighted by researchers. the first one studies spatial variation and commuting behavior in the labor market and housing market, and the second one studies the impacts of spatial mismatch on people in terms of demographic and socioeconomic conditions (horner, ; kim, sang, chun, & lee, ) . in western countries, scholars are mainly attracted to racial or socioeconomic spatial mismatch (mclafferty & preston, ; ross, ) . although residential segregation is still one of the most important causes of spatial mismatch, it is not as pervasive as in the past. nevertheless, the spatial mismatch level seems have not to have decreased in step with the decline of residential segregation, which suggests residential segregation is not the only cause of spatial mismatch. urban sprawl and job decentralization have been regarded as the most important processes resulting in spatial mismatch, as these processes have changed the location choices of people's housing as well as job opportunities (brueckner, ; glaeser & kahn, , p. ; wei & ewing, ) . as population sprawls, people who cannot afford new suburban homes are remain in the old community. as employment sprawls, especially the service and manufacturing jobs which are suitable to poor and under-educated people, poor people who are trapped in urban centers and highly rely on public transportation facilities no longer have access to these jobs (ding & bingham, ; glaeser & kahn, , p. ) . job decentralization also affects people's commuting time. in monocentric cities, decentralization can partly solve the traffic problem because people in the suburbs may have better accessibility to their jobs locally (giuliano & small, ; gordon, kumar, & richardson, ) . however, in a polycentric city, the complexity of urban spaces and unevenly distributed houses and job opportunities have significant negative effects on commuting time (giuliano & small, ) , although others disagree (veneri, ) . job opportunities and spatial mismatch in the context of polycentric development need further investigation. related to urban environment and health, environmental injustice/ inequality has been an important concern of urban equity (mccartney, collins, & mackenzie, ; stewart, bacon, & burke, ) . evidence shows a higher asthma rate among low income and minority groups because of location of transportation facilities such as highways and rail stations (garcia et al., ; rosenbaum, ) . scholars have revealed that vehicles and other small sources of air pollution may contribute more than large pollutive facilities to health problems in poor neighborhoods. busy roads produce both air pollution and noise, and the inverse-distance based relationship between busy roads and negative impacts on health has been uncovered (stewart et al., ) . moreover, urban green space has been recognized as another important factor in environmental inequality and social justice (whitehead, ; wolch, byrne, & newell, ) . green spaces attract people to do more physical activities, and reduce local pollution wolch et al., ) . poor people usually have less access to urban green spaces for two reasons. first, they are trapped in urban centers, which are crowded and there is not enough available area for urban green spaces. second, the region they live in may lack resources, and local government may not be able to maintain urban green spaces. scholars are also concerned with the accessibility to healthy food. suitable accessibility to health food stores is related to better eating habits and results in better health conditions. the concept of "food desert" is used to describe areas lacking access to healthy food, which is usually related to uneven distribution of healthy food stores. however, as most studies are concentrated on the u.s., research is insufficient in other areas, which may have different patterns and mechanisms than the u.s. for instance, garcia, garcia-sierra, and domene ( ) analyze food access in barcelona, and find relative equal accessibilities to food stores in the city; however, the accessibility to organic food is linked to better socioeconomic conditions, and broadly, the restructuring of the retail sector (zhang & wei, ) . in summary, urban inequality is multi-dimensional and these dimensions are closely related. it is still worthwhile to have a comprehensive view of urban inequality. for example, musterd, hochstenback, & boterman ( ) highlight the importance of considering different dimensions such as wealth and income, the structural changes of urban population composition, and diverse changing trends in analyzing socio-economic inequality, which lead to a better understanding of various socio-economic inequality patterns. research on the urban spatial dimensions of inequality highlights dimensions of inequality dynamics that are missed in debates relying on nationally aggregated data. we have argued that present-day inequality trends derive in important ways from the emergence of the new information-based economy in the last few decades. more than ever before, cities are the sites of production in this new economy and it is within cities, and between cities, where present-day inequalities are most conspicuous. inequalities are often created, conditioned, and recreated, in urban space. the contributions to this special issue explore the spatiality and dimensions of urban inequality in multiple perspectives. inequality trends pertain to economic/income inequality, housing quality and affordability, residential segregation, and public health. the studies in this issue are based on a rich and diverse collection of source materials from north america, europe, south america and china, advancing our understanding of the particularities and generalities of urban inequality. together, the papers in this issue suggest that urban inequalities have been on the rise across the globe. this collection of papers also raises important questions, and it is clear that there are still many research gaps to fill. first, the new economy is neither monolithic nor static. the rapid development of digital technologies implies that the working of the urban economy and the new division of labor is a moving target. for example, the uneven economic landscape of u.s. cities has been changing with technological progress and the rise of the network/platform economy. how these forces contribute to urban inequality and how to address arising urban problems remain challenging questions. more generally, theories of urban economic/income inequality in the context of rapid technological change are under-developed and are insufficient to examine emerging patterns of urban inequality (huang & wei, ) . in particular, more research is needed on the significance of the growing segment of self-employed workers and the emergence of the gig economy. this category of workers is spread across different education levels and income classes but they probably share similar vulnerabilities at times of recession. similarly, and partly related to highly dynamic labor markets, housing markets are far from stable. more research is needed on housing in terms of spatiotemporal dynamics and inequality, including shifts from owner-occupied to rental housing. conventional measures of housing inequality are especially problematic in international comparisons. for instance, substantial price ranges may indicate more choices of housing at a variety of prices or it can reflect considerable spatial segregation. in china, especially, underlying mechanisms of housing markets and affordability remain poorly understood. for example, the significance of subway stations for housing prices in china has a close relationship with the over-concentration of jobs and the poor housing affordability in urban centers (li et al., b) . we need more comprehensive studies of housing markets, inequality, affordability, and change. third, residential segregation is an urban phenomenon consisting of different dimensions including race, income, and skill, and studies have confirmed that the different dimensions are interrelated (reardon & bischoff, ) -but these interrelationships vary considerably across the world. despite years of research on residential segregation, different dimensions are seldom analyzed in an integrated framework. the mechanisms underlying residential segregation are highly complex; whereas geographers often pay attention to local factors of change, external and structural forces are often overlooked. fourth, conceptualizations and measurements of income inequality have become increasingly arbitrary (e.g., the economist, ) . this is partly a matter of defining high versus low incomes. in urban contexts, processes of segregation and gentrification tend to involve not the highest incomes (certainly not the infamous " percent") but rather middle and upper-middle incomes and lower incomes, with the former as gentrifiers and the latter as displaced (also see schlichtman & patch, ) . moreover, for a substantial share of urban households, it is wealth and not just income that has become an increasingly important indicator of economic status, i.e., wealth expressed in home equity and retirement funds. accordingly, the distinction between home-owners versus renters is increasingly significant, in cities around the world. lastly, the literature confirms the existence of inter-relationships between different dimensions or forms of urban inequality (anderson et al., ; krivo & kaufman, ; raudenbush & kasim, ) . the coronavirus pandemic was only underway for a couple of months at the time of writing (early march ) but it already pointed to the highly disparate vulnerabilities of different population groups, demographics, and occupational categories (e.g., holpuch, ) . in the new urban economy, homeless people, workers in the low-paid service sector, janitorial staff, hotel and restaurant workers, public transit workers, and those who cannot work from home, have compensated sick days or basic health insurance are among the most economically disadvantaged and most exposed to public health risks. similar vulnerability differentials can be observed in regards to urban environmental threats and hazards, from hurricanes in miami to air pollution in delhi and urban heat waves in tokyo. our understanding of such inter-relationships is limited. the notion of urban 'syndemics' (singer, bulled, ostrach, & mendenhall, ) can be used to indicate the spatial convergence of an array of conditions that define well-being and inequality: problems of, for example, unemployment, low incomes, poor health, low education, and lack of access to amenities, food, and urban services, often are concentrated in space but it is hard to identify the key drivers of such processes. emergent approaches in data analytics and urban policy analytics rely on potentially rich data sources to study the multiple dimensions of urban inequality, and the development of data science and gis can provide powerful tools to increase our understanding. in the meantime, any progress in our understanding of the nature of present-day inequalities requires close attention to their urban spatial dynamics, across the globe. discrimination in the rental housing market: a field experiment on the internet do affordable housing projects harm suburban communities? providing affordable family housing and reducing residential segregation by income urban inequality and the demographic transformation of shrinking cities housing affordability and residential mobility as drivers of locational inequality remaking urban segregation: processes of income sorting and neighbourhood change polarization or convergence? an analysis of regional unemployment disparities in europe over time changes in implicit flood risk premiums: empirical evidence from the housing market migration and inequality minority ethnic groups in the dutch housing market the "urban age" in question delayed spatial 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rental housing applied geography spatial inequality of housing value changes since the financial crisis analyzing the private rental housing market in shanghai with open data analyzing housing prices in shanghai with open data amenity, accessibility and housing values in metropolitan usa technology and economic development slow convergence? the effect of residential segregation on black social and economic well-being the dimensions of residential segregation what (or who) causes health inequalities? who has housing affordability problems? race and social problems china's digital economy spatial mismatch and labor-market segmentation for african-american and latina women ripples of structural economic transformation socioeconomic segregation in european capital cities opposition to affordable housing in the usa. housing mumbai's mysterious middle class the theoretical imperative of comparative urbanism india's urban future urbanization and economic development epilogue: suburbs as transitional spaces the united states: suburban imaginaries and metropolitan realities the rise and fall of regional inequalities with technological differences and knowledge spillovers how has the distribution of income in new york city changed since capital in the twenty-first century cognitive skill and economic inequality income inequality and income segregation the work of nations trade and regional inequality environmental politics and policy racial differences in residential and job mobilitys dimensions and dynamics of residential segregation by income in urban canada wealth inequality in the united states since . cambridge ma, october: nber working paper series. # the global city cities in a world economy housing inequality and housing poverty in urban china in the late s gentrifier? who, me? interrogating the gentrifier in the mirror the constitution of the city independent workers and the modern labor market growing socio-spatial inequality in neo-liberal times? the roles of housing and poverty in the origins of homelessness syndemics and biosocial conception of health the uneven distribution of environmental burdens and benefits in silicon valley's backyard the price of inequality housing in the evolving american suburb urban polycentricity and the costs of commuting public housing magnets global urbanization research from to inequality and the measurement of residential segregation by income in american neighborhoods regional development in china spatiality of regional inequality geography of inequality in asia urban expansion, sprawl and inequality neighborhood, race and educational inequality beyond convergence: space, scale, and regional inequality in china population dynamics and ethnic geographies in oslo the wood for the trees racial residential segregation urban green space, public health, and environmental justice intrametropolitan fdi firm location in guangzhou analyzing spatial heterogeneity of housing prices using large datasets continuity and change in the restless urban landscape policy change, amenity, and spatiotemporal dynamics of housing prices in nanjing convergence or divergence in los angeles spatial inequality and dynamics of foreign hypermarket retailers in china economic transition, urban hierarchy, and service industry growth in china export structures, income inequality and urban-rural divide in china contradictions in china's affordable housing policy we would like to acknowledge research assistance of yangyi wu, helpful comments of bob argenbright, and the funding of the us national science foundation ( ) and the ford foundation ( - ). supplementary data to this article can be found online at https://doi. org/ . /j.apgeog. . . key: cord- - r jdffu authors: orlova, galina; morris, jeremy title: city archipelago: mapping (post)lockdown moscow through its heterogeneities date: - - journal: city soc (wash) doi: . /ciso. sha: doc_id: cord_uid: r jdffu nan online, people responded to the "fall of self-isolation" sarcastically, with an untranslatable pun on the words 'get well' (after the coronavirus) and 'amend' (the russian constitution): ("strana poshla na popravki"). public health concerns were replaced by a grim focus on the political regime's diseased mutation. in fact, moscow's hybrid practices of biopolitical care -the domestication of "the great imprisonment", with biosecurity testing, buggy digital technologies augmented by direct police control, and interventions into urban rationalities in the spirit of soviet nonconformist art -were abruptly curtailed by an autocrat's whim for his plebecite. epidemiologists and political experts agreed that the end of self-isolation in moscow was due to vladimir putin's desire to push ahead a national vote on july . the willed suspension of the pandemic in moscow provides a moment for reflection on the (dis)appearing city in quarantine. jeremy writes from afar; galina from close-up, from an apartment in the "quiet center" of moscow, which has shrunk for an inhabitant in lockdown to an island-quarter. covid- is an urban disease. in china, wuhan put on the crown, in the usa -new york, in spain -barcelona, then in russia, with its internal colonization and centripetal geography, predictably it was moscow. in a metropolis where around % of the population lives, % of russians with a diagnosis were infected at the end point of self-isolation. whereas people arriving in the capital from at-risk countries faced -day quarantine, in the russian regions those who arrived from moscow were put in isolation. to avoid an official 'state of emergency' which would have meant taking on a massive financial burden, city hall adopted various heuristics to manage quarantine. from march , the moscow had a high-alert mode, from the th -self-isolation for those +, from the th -self-isolation for all. the delegation of responsibility for their own health and well-being to citizens, after recent restrictions on freedoms, looked neoliberal. at the same time, the scope of quarantine education addressed to ignorant citizens and belief in its effectiveness, suggested the return of soviet sanitary propaganda (shok, beliakova, ) . in conditions of lockdown uncertainty, the boundaries of self-isolation were delineated by rituals of taking out garbage, buying food and medicine, dog walking. from april , fines of , - , rubles were imposed for each violation. on april , quarantine met the control society with digital codes for trips around the city. since may , wearing masks and gloves became mandatory in stores. minister asked the moscow mayor "organizationally and methodically" to help colleagues "on the ground", sobyanin became the face of the "virus federalism" and the capital's protocol "counteracting the spread of coronavirus infection" became a model to follow. while the self-isolation regime is gone, the "glove-mask system" remains. entering public transport or shops without ppe is prohibited. disposable masks -medical blue, three-layeredare found far beyond pharmacies: at newspaper stands, at the ice cream kiosks, in cheap and expensive grocery chains. at the reopened farmfoods store, half-empty due to supply disruptions, masks are at a discount. in may, they cost from to rubles, in march-april -up to an extraorbitant and you could buy them only on the internet from resellers, thirty-times more expensive than in . prices began to rise in february. at the peak, the government tried to mandate them, but immediately abandoned this measure. the rhytym of the pandemic in moscow was not only the appearance or absence of masks, but their price in(de)flation. in the russia that imported the bulk of masks from china before covid- there were three domestic manufacturers. city hall not only took ownership of the largest factory but removed its facilities from the city of vladimir to the capital, turning the pandemic into a "moscow state business". two thirds of masks from the moscow government (about million items a week) were sold at cost to hospitals and communal services, , -for a "standardised price" of rubles in the metro. the rest were put into a city administration reserve. compared to the free distribution of mask not only in the paris metro, but on buses in russia's far east, moscow's choices provoked discussion of the political economy of ppe. vladimirites were disgusted by the capital's betrayal leaving them not only without protection, but one profitable business less. their objections to internal colonialism were tempered with racist suggestions that the masks from moscow -now produced by "immigrants from disadvantaged countries of the near abroad" -were now "less hygienic". muscovites discussed the superprofit extracted by city hall, and supposed that "since they bought the plant, the mask-regime will never end." stuck between epidemiological citizenship and city-state paternalism, they claimed that the government had no moral right to demand wearing masks without free distribution. citizens made a hopeless diagnosis -"it's all capitalism and they don't give a shit" -and continued to buy masks. the case reveals the complex nature of state-capital conjunctions in the russian capital. appropriating profitable ppe businesses, strategically significant in an epidemic, city hall enters the order of state capitalism. obliging citizens to wear masks and offering them at commercial prices, they interpret civic responsibility in a neoliberal mode as a personal transaction according to the logic of capitalist realism that anathemizes any alternative to marketised relations (fisher ). nonetheless the virus' acceleration of neoliberalism does not completely destroy the legacy of the soviet social state, instead weakening and transforming it beyond recognition. by sending masks to hospitals at cost price, moscow combines the logic of minimal profitability and sluggish paternalism. opting to create a reserve fund instead of free distribution of masks, it reproduces a pattern of deformed care without expenditure, developed by the federal government via the russian reserve fund. state capital accumulation has a perverse obsession with curtailing the circulation -of money, of civic potential, -we call this the political economy of "the untouchable reserve". after the virus transformed the city into a host of hostile surfaces, the sanitary service enlightened muscovites that the infection "can stay in the air for hours, on copper -for hours, up to hours on pulp and paper surfaces (documents, envelopes, folders), for - days on plastic and metal." the developing corona-market offers a "cold fog" method of disinfection from roubles per m . an invitation to the wake of a neighbour dead from covid, now includes: "everything is disinfected." public spaces -sidewalks, underpasses, entry-ways -are treated at city expense. the deputy mayor first earmarked , units of tractor-street sprayers, deploys , . the air hangs with a bleach smell from the long-forgotten soviet sanitary aromascape while the yellow sanitisers in the metro whiff of the society of consumption and bananas. muscovites happily use them and discuss whether the big disinfection is comparable to urban beautification programs famous for exorbitant expenses and corruption. and if there isn't much point in treating open surfaces, as epidemiologists say, should this be recognized as an urban antiviral ritual? our entrance-way, which according sanitary doctors remains the most "forgotten place in terms of anti-epidemic measures", is disinfected twice daily. bumping into disinfectors in chemical protection suits with spray guns and getting coated by a dose, you realise the danger, and no longer go out without a mask. someone repeatedly adds in pencil: "unsatisfactory" to the assessment in the disinfection schedule posted by the elevator. the repairman -tired, in a cotton mask slipping down -is also unhappy: the chemicals have damaged electrical contacts, and now the elevator serves only four floors out of twelve. this metonymizes the city in quarantine as an assemblage of relative safety, partial functionality, attempts to reprogram and restore lost connectivity. maintaining moscow's reputation as a 'smart city', city hall placed its bets on the rapid development of digital control over self-isolation. from april any non-hospitalized infected were obliged to stay at home and install a special mobile app -social monitoring, developed by the city it department. from april , muscovites needed sixteen-digit qr codes to make daily work trips, single emergency trips, and twice-weekly trips for personal and private needs. police, taxi-drivers and transit workers mobilized to check codes using the transit department's moscow assistant app. regimented timetables of walks were dictated via infographics interfaces. drones and quadcopters for tracking social distancing in re-opened restaurants were moscow's moment to jump the shark. jung won sonn and colleagues, analyzing the effective use of technology to reduce the risks of a pandemic in south korea with smart city technologies, conclude that covid- is the first epidemic in history for which humanity living in cities has come up with a ready-made response system. aggregating mobile operator data, geolocations of bank transactions and transport cards allows the precise contact tracing, avoiding major quarantine. the researchers regret that countries with developed digital infrastructure -with the exception of south korea and taiwanhave not made use of this advantage. (sonn et al. ) . russia, where during crisis the development of a new platform and apps was preferred, entailing large upfront costs, is a special case. while yandex -russia's google and the co-owner of popular taxi, delivery and mapping apps, -published a "self-isolation index" using its own digital infrastructure and aggregating big data, city hall chose to develop apps from scratch. work requiring months was implemented in weeks with many bugs and inefficient decisions. lacking auto-verification, qr codes turned moscow assistants into nurses for an infirm technology. massive queues formed at metro entrances as policemen were forced to manually input codes to their devices. technical faults were accompanied by social de(trans)formations, compensatory improvisations, and abuses. when moscow assistant could not cope with the flood of requests, qr encounters simulated governing. the cancelling of drivers' codes without explanation led to the use of "service position" and informal connections to obtain permissions. ordinary muscovites with covid- paid for geolocation failures, non-stop selfie requirements, multiple disconnections of the social monitoring, developed from fragments of code written in ten days for a pilot project to monitor the transport of domestic waste. heavy fines, the denial of technical errors by city hall forced the victims of smart lockdown to unite in the fb-community fined for getting sick and to complain about the app in court and to google play. techno-political failures of moscow lockdown are full of heterogeneities. repressive social monitoring is the first manifestation of a biosecurity regime replacing biopolitics. while biopolitics featured authorities' concern with the life of population, biosecurity is built on the responsibility -including legal -of citizens for their health (agamben ) . for muscovites, fined for getting sick, buggy mobile apps became the real punishment. the incoherence of urban mobility monitoring destroyed the technological continuity of the society of control (deleuze ). to check a qr-code through moscow assistant, you need a policeman or a taxi driver in person with a mobile citizen. taxi drivers tell of the discomfort that arose performing these police duties. the mayor's office sees voluntary assistance and civic duty in them, but just in case, offers numerous sanctions for those who refuse to help. in a country where civil society is supposedly weak, the prosthetics of digital technologies during lockdown risk not so much strengthening the police state but accelerating the emergence of a "police society". a booklet from ritual, the moscow funeral service and operator of moscow cemeteries, dropped into our postboxes on the eve of self-isolation for +. the use by a commercial firm of the state services' design suggests a newly cozy relationship between the traditionally shady funeral business and russian stateness. last summer, this convergence took the form of a corruption scandal, linked to the high-profile case of journalist ivan golunov, framed for his investigation of murky dealings between moscow undertakers and state security organs. this spring ritual prepared inhabitants for death and loss, warned against contacts with "black agents", informed about prices and social subsidies, also offering people something that in the extreme circumstances of pandemic they expected but did not receive from the state -care. care, which remains for russians one of the most important regimes of affective expectations in political communication with authorities, masks hierarchies and injustice (bogdanova ) . care certificates from ritual guarantee the owners, if they died within a year of purchase, burial at the operator's expense. this offer had the side effect of interpellating tenants as potential victims of the virus. yandex informed muscovites about the preparedness of ritual, that "will come in handy", for the pandemic: protective equipment and coffins in ready supply. the ministry of health published temporary recommendations -later rescinded -including a prescription to bury infected bodies in sealed coffins. who and russian virologists confirmed that the virus is not transmitted from the dead to the living. funeral services are not under the authority of the health ministry. nonetheless, the protocol was entrenched: coronavirus victims are sealed in bags, and not released to relatives. ritual posted a "viral" instagram burial video: a hazmatsuited funeral team, disinfectant poured into the grave, a clutch of relatives frozen in the distance, the pit fill with fir branches as a natural disinfectant and only completed. the union of ritual workers has spoken out against the use of garbage bags as destructive to the social order and turns funerals from care into disposal. refusing large-scale support for population and business, the authorities compiled lists for selective state aid. the presidential one featured a child allowance. moscow -supported the newly unemployed. the government made two lists -for system-critical firms (including bookmakers!) along with a dozen industries extremely vulnerable to the effects of the epidemic. the chair of the chamber of commerce proposed including outdoor ads, which would lose up to % of revenue in deserted cities, in the second list. simultaneously, he emphasized the critical role of billboards in informing people about virus protection, the wwii anniversary, and the upcoming plebiscite. was this transition from the affected to having critical significance a transition from commercial advertising to propaganda? did this discursive merging tell us more about saving the industry at the expense of state orders? even in the small section of my selfisolation route, billboard changes perform the symbolic dynamics of quarantine. when le village magazine asked sergeant kurakin, who was checking qr codes at the metro, why people disobey quarantine -the answer was 'to work'. closure and opening of quarantine both draw a labor division. mobilized doctors, taxi drivers, grocery and utility workers, couriers, bus drivers -these high-risk occupations, deemed essential, were never locked down. 'partisan' hairdressers worked clandestinely. switching to 'distance working', people were faced with the hardships of endless digital labor and its invasion of privacy, small and medium business -with the need to pay salaries in the absence of revenue and state support. moscow closed more comprehensively than other russian cities. reopening, formally based on the topological 'safety' ranking of occupations, was multi-step. may -the same time as mandating obligatory masks in shops -construction sites and industry restarted. may government service centres (by appointment) and car-sharing services (partially) returned. other services were divided into three stages in june, visualized in infographics: first hairdressers and cemeteries, then café verandas and dental clinics, and finally, kindergartens, fitness clubs and restaurants. the city reopening was asynchronous and incomplete, in turn affecting the political and economic in complex and unpredictable ways. but we learn nothing from them about changes in the life of the city or its inhabitants. to think of a large city in quarantine as archipelago is to problematize the qualitative changes in urban life during self-isolation, mapping the diffusion of sociality and following heterogeneities of (non)actualized presence. the implosion of urban imagination, the narrowing of vision and atrophied habitus -all of what creates so much discomfort and inconvenience for city-dwellerscan open new analytical perspectives in how to deal with impoverished forms of dwelling and not be afraid of attending to its fragmentation. the playground taped off. footpaths along which friends walk their puppy. i wave to them from my balcony. rubbish containers next to the dovecote "love and doves" that emptied during quarantine. . wine island, where the store consultant week to week talks about wine from more and more distance. . the island of a closed house museum of pushkin's uncle and food, delivered from may with no charge by taxi firm. . island with more cheap food, water and hardcore disinfection. here i bought my second pack of masks (the first were from the internet at a crazy price). here my friends live. all springtime we would have drinks and read poetry on fridays in whatsapp. . the far post-office island, meters from home. i went there a couple of times at the end of selfisolation. . the far bank island at a distance of km from home. . the phantom island of work. humanities campus of "vyshka", where i have not been since the middle of march, working at a distance. colleagues in fb don't believe in its existence. i see the building every day from my window and do not believe either. . billboards from our photos. . the island-building of ailments, visible from my window, where all april ambulances -the dominant vehicle in the empty city -came time after time. . moscow city, a group of skyscrapers on the horizon, visible with unprecedented sharpness. usually -and now once again -they are smoggy. image by galina orlova. sovetskaya traditsiya pravovoj zashhity, ili v ozhidanii zaboty [the soviet tradition of legal protection or awaiting care postscript on the societies of control capitalist realism: is there no alternative? kartografirovanie ostryx socialnyx problem trebuet ostorozhnosti [mapping acute social issues requires caution how soviet legacies shape russia's response to the pandemic: ethical consequences of a culture of non-disclosure smart city technologies for pandemic control without lockdown at the end of march, the dismantling of outdoor ads from the frozen centre of moscow gave way to mobilization. from billboards, placed every - meters, well-known moscow doctors urged muscovites to stay home, wear masks and not touch their faces. after april, this template was adapted to enhance affective solidarity and the formation of quarantine communities. doctors are no longer given voice, they are thanked. and young people are hailed as volunteers. closer to the garden ring sanitary enlightenment is interspersed with posters for victory day. in early summer, commercial advertising has returned as a (post)quarantine hybrid -mcdonald's with both hands voting for hand washing. the epidemiological safety and the upcoming voting in this austere carnival of signs do not leave room for bigmacs yet.the moscow government justified priority reopening of industry as 'least dangerous' because of the absence of direct contact between producers and consumers. however, no one hid that the resumption of construction work -masked, with a reduction in shift and brigade work -was due to the shared economic interest of lobbying developers and city hall, and the problems of labour migrants. according to mobile operator data, up to . million people from russian regions left moscow during quarantine. but citizens from the cis countries, mainly engaged in construction, were locked up in the capital without a livelihood. moscow officials saw criminal risk in migrants without work, reifying care about them as an interface of profit and biopolitical inequalities.if the resumption of construction strengthened socio-economic marginalizations existing before quarantine, the partial opening of car sharing produced new inequalities. at the end of may, the renewed service only allowed five-day-plus leases, unaffordable to most. as for mandatory disinfection of the cabin before returning the car, this was another materialization of sharing as a "new dangerous". several years ago, 'le monde diplomatique' published an imaginary palestine map. the occupied territories were represented as the sea; the authority-controlled ones -as islands of an archipelago. numerous maps of the pandemic, regularly described in military metaphors, depict the covid- occupation in a different way -not framed through absent space but as more or less filling it, and pushing out of frame alternatives of resistance, coping and co-existence. from maps of pandemic moscow we can see how the concentration of the virus shifts from the prosperous centre and south-west, where the epidemic began, to the northern, eastern and south- key: cord- - a pq e authors: freitas, Ângela; rodrigues, teresa c.; santana, paula title: assessing urban health inequities through a multidimensional and participatory framework: evidence from the euro-healthy project date: - - journal: j urban health doi: . /s - - - sha: doc_id: cord_uid: a pq e urban health inequities often reflect and follow the geographic patterns of inequality in the social, economic and environmental conditions within a city—the so-called determinants of health. evidence of patterns within these conditions can support decision-making by identifying where action is urgent and which policies and interventions are needed to mitigate negative impacts and enhance positive impacts. within the scope of the eu-funded project euro-healthy (shaping european policies to promote health equity), the city of lisbon was selected as a case study to apply a multidimensional and participatory assessment approach of urban health whose purpose was to inform the evaluation of policies and interventions with potential to address local health gaps. in this paper, we present the set of indicators identified as drivers of urban health inequities within the city of lisbon, exploring the added value of using a spatial indicator framework together with a participation process to orient a place-based assessment and to inform policies aimed at reducing health inequities. two workshops with a panel of local stakeholders from health and social care services, municipal departments (e.g. urban planning, environment, social rights and education) and non-governmental and community-based organizations were organized. the aim was to engage local stakeholders to identify locally critical situations and select indicators of health determinants from a spatial equity perspective. to support the analysis, a matrix of indicators of health determinants, with data disaggregated at the city neighbourhood scale, was constructed and was complemented with maps. the panel identified critical situations for urban health equity in indicators across eight intervention axes: economic conditions, social protection and security; education; demographic change; lifestyles and behaviours; physical environment; built environment; road safety and healthcare resources and performance. the geographical distribution of identified critical situations showed that all city neighbourhoods presented one or more problems. a group of neighbourhoods systematically perform worse in most indicators from different intervention axes, requiring not only priority action but mainly a multi- and intersectoral policy response. the indicator matrices and maps have provided a snapshot of urban inequities across different intervention axes, making a compelling argument for boosting intersectoral work across municipal departments and local stakeholders in the city of lisbon. this study, by integrating local evidence in combination with social elements, pinpoints the importance of a place-based approach for assessing urban health equity. abstract urban health inequities often reflect and follow the geographic patterns of inequality in the social, economic and environmental conditions within a citythe so-called determinants of health. evidence of patterns within these conditions can support decisionmaking by identifying where action is urgent and which policies and interventions are needed to mitigate negative impacts and enhance positive impacts. within the scope of the eu-funded project euro-healthy (shaping european policies to promote health equity), the city of lisbon was selected as a case study to apply a multidimensional and participatory assessment approach of urban health whose purpose was to inform the evaluation of policies and interventions with potential to address local health gaps. in this paper, we present the set of indicators identified as drivers of urban health inequities within the city of lisbon, exploring the added value of using a spatial indicator framework together with a participation process to orient a placebased assessment and to inform policies aimed at reducing health inequities. two workshops with a panel of local stakeholders from health and social care services, municipal departments (e.g. urban planning, environment, social rights and education) and nongovernmental and community-based organizations were organized. the aim was to engage local stakeholders to identify locally critical situations and select indicators of health determinants from a spatial equity perspective. to support the analysis, a matrix of indicators of health determinants, with data disaggregated at the city neighbourhood scale, was constructed and was complemented with maps. the panel identified critical situations for urban health equity in indicators across eight intervention axes: economic conditions, social protection and security; education; demographic change; lifestyles and behaviours; physical environment; built environment; road safety and healthcare resources and performance. the geographical distribution of identified critical situations showed that all city neighbourhoods presented one or more problems. a group of neighbourhoods systematically perform worse in most indicators from different intervention axes, requiring not only priority action but mainly a multi-and intersectoral policy response. the indicator matrices and maps have provided a snapshot of urban inequities across different intervention axes, making a compelling argument for boosting intersectoral work across municipal departments and local stakeholders in the city of lisbon. this study, by integrating local evidence in combination with social elements, pinpoints the introduction evidence on health inequities between and within cities has been globally documented across all countries and regions, regardless of the level of economic development and health system organization [ ] [ ] [ ] [ ] . the places where people live within a city and how that city is governed can shape individual and population health and create inequities [ , ] . there is ample evidence that health inequities have a spatial footprint, often following the geographical patterns of inequality in the social, economic, built and physical environmental conditions in which people are born, grow, live, work and age-the so-called social determinants of health (sdoh) [ , ] . these conditions are not distributed randomly within a city, the result of which creates different living conditions, degrees of vulnerability, levels of exposure to environmental risks and hazards, levels of access to resources, services and amenities and the populations' chances of living a flourishing life [ , [ ] [ ] [ ] [ ] . tackling the harmful effects of an unequal distribution of sdoh within a city is a matter of health equity and justice, understood here as principles underlying the commitment to provide conditions and opportunities to every individual to achieve good health and wellbeing, regardless of one's place of residence, ethnicity, age, gender identity, sexual orientation or economic and social situation, among any other status likely to cause disadvantage [ ] [ ] [ ] . policy decisions of different sectors shape processes that influence the distribution of urban determinants of health. examples of this include access to education, economic opportunities, social protection, safety, healthcare, social services, culture, sports and recreation, provision of housing, air and water quality, public transport, green spaces and healthy food [ , [ ] [ ] [ ] . for this reason, resulting inequities are considered both multidimensional and a complex problem: there are multiple contributors and multiple solutions, and these can neither be viewed in isolation nor understood without being situated in their place and local context [ , ] . while healthcare policy can go some of the way, when it comes to addressing the causes of urban health inequities, gains can only be achieved via the engagement and actions of other sectors. local and municipal governments play a very important role, not only by having the capacity to effect change through policies and interventions to address problems locally and allocate or redress the inequitable distribution of resources, but also due to their ability to work across sectors and with local stakeholders [ , [ ] [ ] [ ] [ ] . the united nations agenda for sustainable development, reflected in the new urban agenda [ ] and in the sustainable development goals (sdgs) [ ] , places strong emphasis on the leadership role played by cities when taking action to create healthier and more sustainable environments as they are considered the settings that hold the highest potential to address the determinants of health. in this context, it is important to note the work that the who healthy cities movement has been developing over the last years to put health on the social, economic and political agendas of city governments across the globe. embedded is the recognition that more effective initiatives to address health inequities require a shift of paradigm in health promotion: we must reduce "the focus on individual behavior change interventions within settings and focus more on interventions which change the structure of setting themselves as this is what constitutes action on broader determinants of health inequities" (p ) . yet, in an environment of great complexity, the following question arises: "what issues should governments consider when trying to identify what evidence is useful?" (p ) evidence-based policy is based on the principle that decisions are informed by available evidence and this should include a rational analysis [ ] capable of representing the key issues, illustrating the gaps in equity among neighbourhoods, and ultimately inform action to close those gaps [ ] [ ] [ ] [ ] . several initiatives have been undertaken over the last years to compile and standardize urban health indicators with the aim of informing urban policy and decision-making; worthy of mention is the who urban health equity assessment and response tool-urban heart [ , ] . recent literature reviews on the development and use of metrics for analysing urban health equity highlight the existent plethora of indicator frameworks which exhibit great diversity in the aim, spatial scale, domains analysed, characteristics measured, indicator selection methodology and data visualization [ , [ ] [ ] [ ] [ ] . a system of urban health equity indicators using "area-level health determinants" is of considerable value to city mayors, municipal departments and other local stakeholders because they allow for monitoring related inequities across place and time and address critical situations and set priorities [ ] . furthermore, disaggregated data at the level of city neighbourhood invariably reveal inequities, stemming from a locational or "placebased" disadvantage. within a setting that is geographical by nature-the city-the adoption of a place-based approach allows for the analysis of health inequities through a lens that incorporates data on local indicators (of economic, social, physical and built environment) [ ] and involves multiple stakeholders and the community [ , [ ] [ ] [ ] [ ] . making sound decisions to determine the primary inequities to address, thus producing desirable outcomes for population health, is both a technical and a social process [ ] . the inherent complexity and multidimensionality of assessing urban health demand evidence from multiple fields of knowledge and the engagement of stakeholders from different sectors [ , ] . participation processes at the local level are broadly advocated and considered a current trend in urban health studies [ ] , not only because they provide a venue for inclusive decision-making [ ] but more importantly contribute to efforts to reach agreement on an issue where plurality and heterogeneity of points of view arise [ ] . stakeholders have a wide range of social values and interests that result in different perceptions of what evidence is most useful and relevant to guide priority setting [ ] . this necessarily involves an effective use of stakeholders from a wide range of fields interpreting that evidence for them in a clear way and applying appropriate approaches to elicit information from them, thus making their perspectives explicit when making choices [ , ] . the euro-healthy project (shaping european policies to promote health equity) was a -year project ( - ) funded by the european commission to advance knowledge on policies with the highest potential to promote health equity across european regions, with a specific focus on urban areas. at its core is the application of a multidimensional and participatory approach to population health with the goal of understanding the key drivers of health inequities and advancing evidence and methods to better inform policymakers at different decision-making levels, the european union (eu), national, regional and local [ , , ] . the flagship tool of this project is a population health index (phi), a measure that characterizes european population health across multiple areas of concern, dimensions and indicators of health determinants and health outcomes [ ] [ ] [ ] [ ] . the city of lisbon was engaged in this project as a case study for the analysis and evaluation of policies with potential to promote health equity on an urban scale. the specific aim was to analyse municipal policies considering not only the benefit to promote health and reduce inequities in the sdoh among city neighbourhoods but also the doability [ ] in light of two scenarios for the evolution of health inequalities in europe (detailed information can be found in [ ] ) [ ] . a fundamental step was to build the evidence base for the policy evaluation exercise, which comprised the structuring of intervention axes (areas of concern in which the city has problems that can be addressed by policies) and the definition of a multidimensional set of indicators reflecting the status quo of urban health equity issues in lisbon. this paper describes this first stage of assessment and the respective outputs, namely the set of indicators identified as drivers of place-based health inequities and the implications for future policy prioritization. the design of this socio-technical process was based on the following key assumptions and principles: (i) multidimensionality of urban health equity: recognition that multiple conditions influence urban health and sdoh are entry points for action to promote health equity, as the analysis of their unequal distribution within a city represents a crucial requirement to identify appropriate policy responses [ , , , ] ; (ii) evidence-based: informed by key sdoh and looking to all urban features likely to produce health inequities, the domains defined for analysing urban health inequities in lisbon follow the areas of concern considered relevant to evaluate population health in the european context, under the euro-healthy project [ , , , ] ; (iii) data-driven and context-specific: availability of data to measure indicators that are relevant for the specific context and can characterize local conditions. data is gathered from area-level indicators to capture geographical inequalities, with readily available data representative at the neighbourhood scale [ , , , , ] ; (iv) data quality and validity: the selection of indicators is based on readily available and timely data at the local level, obtained from official and accurate data sources that report current rather than historic data [ , ] ; (v) policy-relevant and action oriented: indicators need to be linked to policies and interventions with potential to effect change at the local level. indicators provide information that is understood by those responsible for taking action and are considered appropriate and useful for guiding local decision-making. data is spatially disaggregated at the neighbourhood level to inform place-based and multisectoral action [ , , , ] ; (vi) stakeholder engagement: a range of stakeholders from a variety of backgrounds must be involved, as local knowledge is considered vital, alongside with data, when it comes to both identifying and analysing context-specific urban health inequities. the engagement of key players includes local government, healthcare services and local associations and community groups. the objective is not necessarily to reach mutual consensus or to come to a joint decision on what the priority interventions will be, given that it is the policymakers who ultimately hold the final authority and are held accountable for final decisions [ , , ] .; (vii) participation and collaborative process: the participatory process is designed to promote shared understanding about urban health inequities while capturing multiple stakeholders' values and perspectives, creating a collaborative environment that enables management of eventual conflicts of values and promote agreement. the aim is to create a joint learning experience as a means of creating space for all stakeholders to express their views [ , , , ] . (viii) output validity: the outputs must be considered valid, that is, able to reflect what it is intended to reflect as relevant and meaningful for the specific context of evaluation and local situation (contextual validity), by the group of stakeholders actively engaged in the participatory process (participatory validity). here, validation is assessed through "face validity" [ ] , that is, in the view of the evidence presented (indicator data) and the variety of perspectives, the group considers that the indicators selected provide a general picture and are representative of the main drivers of urban health inequities (intersubjective and content validity). additionally, the process must increase empathy among the participants (empathy validity) [ , , ] . the process of identification of urban health inequities in the city of lisbon involved three steps: the formation of a local stakeholder panel ( step ), the development of a provisional list of indicators of sdoh and collection of available data at a neighbourhood level (step ) and the organization of stakeholder workshops to consult and collect views on what indicators are influencing urban health inequities and where (in which neighbourhoods) the action addressing identified issues is more needed (step ). in the following sections, more information is provided on the panel members, indicator data and workshop protocol. step : formation of the local stakeholder panel a total of individuals, representing regional and local institutions from different sectors, were invited to participate and form the local stakeholder panel. a welcome and introductory session was organized to allow stakeholders to (i) become better acquainted and engage with the topic of urban health and health equity from a sdoh approach; (ii) have a general overview of the lisbon case study, namely its objectives and methodological approach, and (iii) share commitment towards their roles and tasks. overall, the panel represented different stakeholder groups: (i) local and regional government (including elected officials and officers from various departments linked to urban determinants of health); (ii) charities and other non-profit and nongovernmental organizations (e.g. working in the field with vulnerable or marginalized populations) and (iii) public health and healthcare (e.g. from primary healthcare and regional health planning) (table ) . step informed by the euro-healthy project [ , , , ] , eight independent intervention axes for appraising health were considered: (i) economic conditions, social protection and security, (ii) education, (iii) demographic change, (iv) lifestyle and health behaviours, road safety and (viii) healthcare resources and performance. to investigate how lisbon performed in these intervention axes, the research team selected indicators to be included in the provisional matrices. along with the need to be context-specific (relevant for the context of the city of lisbon), the selection of indicators was based on the following criteria: (i) ability to describe and measure one relevant aspect for health within each intervention axis (e.g. socioeconomic characteristics of population within economic conditions, social protection and security; environmental factors that can influence health within built environment and physical environment); (ii) address health determinants that can be shaped by local policies and interventions, (iii) data disaggregation at the civil parish scale, to capture inequalities and enable the intra-city analysis of inequities and (iv) data quality and validity. indicator data was collected for the municipality of lisbon, at the civil parish level (the smallest administrative unit in portugal), for the year with the most recent data (between and ) and relied, as much as possible, on the use of available datasets from official statistics. together with the use of indicators provided by statistics portugal (e.g. census data on population, employment, education, housing), a number of indicators were built by the research team, specifically for this study, using data provided by the city departments (e.g. data on pollution, built environment, transportation, social and healthcare services) and by stakeholders involved in the study, representing local ngos (e.g. data on the living conditions of vulnerable populations, such as the elderly and homeless). the municipality of lisbon supported the data collection by authorizing access to local databases and geographical data (for mapping). as complementary to the main list of indicators of health determinants, data on health outcomes (e.g. mortality by cause of death, disease incidence rates, hospital discharges) were also collected and mapped at the civil parish level. for each indicator, relevant information was gathered in the form of an identity card with the following attributes: (i) indicator metadata (name of indicator, definition, unit of measurement, calculation, geographical scale, year of data, data source), (ii) indicator purpose (health-based rationale stating how the indicator effects health) and (iii) map showing the respective geographical distribution across the city of lisbon (data disaggregated at the civil parish level) (see fig. ). step : workshops two workshops were held in lisbon between november and february . in the first workshop, participants were divided into three multidisciplinary workgroups. each group was assigned a specific set of intervention axes and respective indicators according to the stakeholders' area of expertise or work ( table ). the aim of each workgroup was to identify locally critical situations with respect to health determinant inequities and select indicators that may be entry points for priority intervention. the workshop protocol was built around the analysis of data collected on indicators based on the following questions: [ ] what indicators (health determinants) are the key drivers of local health inequities? and [ ] where (in which civil parishes) is the priority action that addresses those indicators most needed? to support the analysis, the research team prepared material for consultation in the workshops. the consultation material included the following documents: (i) three indicator matrices with the indicators of health determinants (in rows) and respective performances in each geographic unit- civil parishes (in columns) across the eight intervention axes and (ii) a dossier with each indicator identity card, with metadata, its "population health meaning", that is, its relevance and how it effects health, and a map showing how the indicator varies across the civil parishes. each participant was provided with a matrix, in line with the axes assigned to the respective workgroup (see figs. , and ) . the indicator data was organized in the matrix in such a way that participants could easily analyse the performance of each civil parish for each indicator against given benchmarks: the city average, the worst and the best performances within the municipality of lisbon. each of the civil parishes was colour-coded for each of the indicators using the following metric: performances worse than the city average (cells shaded in dark grey) and performances better than the city average (cells shaded in light grey). in each indicator, the two best (and worst) city parishes were also highlighted (performance in bold). the colour attributed to the "worse than/worst" and "better than/best" performances reflect a value judgement considering the potential effect of the indicator on population health. for instance, a civil parish presenting higher percentages of unemployed people when compared with the city average is colour-coded in dark grey, considering that high levels of unemployment have a negative impact on health. in this first workshop, two exercises were conducted. the first exercise was to seek the opinion of each participant as to which civil parish/indicator represented critical situations for health equity in the city of lisbon by marking the cells in question red. for the purpose of this study, a critical situation depicted a civil parish where, in light of the evidence provided, its performance in one or more indicators would potentially have a negative effect on health equity in the municipality and should consequently be considered a priority for intervention. the analysis was individual and was made in light of the consultation material provided, namely the publication which included the indicator's identity card and respective maps (see fig. a ). the second exercise was to discuss the individual assessments (matrices with cells coloured red) within each workgroup and to reach a tentative agreement on a set of indicators considered problematic situations and potential entry points for intervention (see fig. b ). after the workshop, and in order to reach a clear and effective agreement on a single matrix of critical situations by workgroup, individual matrices were analysed by applying a majority agreement rule. the workgroup opinion (aggregate of individual assessments) was calculated taking into account the number of participants who had shaded a cell in red in relation with the total number of participants in the workgroup. then, a single workgroup matrix was built showing the cells shaded red by more than % of the participants. the second workshop was performed to validate the resulting single workgroup matrices. the three workgroups were presented with the respective aggregate of individual assessments and given the opportunity to revise the single workgroup matrix and to remove, change or add critical situations (fig. c) . the main aim of the assessment was to obtain a comprehensive picture of the critical situations across the city by examining the geographical distribution of several health determinants at the neighbourhood scale (civil parishes). the final matrix with the identification of the critical situations (cells coloured in red) reflects the indicators and the geographical areas with the poorer performances, pinpointing the status quo of inequalities that should be addressed in order to promote equity in the city of lisbon. the assessment was made considering eight independent intervention axes, meaning that stakeholders worked each intervention axis independently without prioritizing one above the other, and that participants did not weigh the importance or ranked indicators. in the matrix and within each independent intervention axis, they identified the respective indicators and the civil parishes that, given the material provided (data and maps) together with their own local knowledge and perceptions, are in "red alert". the final matrix of critical situations is shown in fig. . from the initial set of indicators, a total of were selected ( %), representing a wide range of health determinants where one or more civil parishes revealed worse performances and were marked red (see table ). from this list, more than one third ( . %, indicators) are from built environment. there are three intervention axes where all the indicators included in the provisional matrix were selected; this occurred with lifestyles and health behaviours, physical environment and road safety. an examination of the distribution of critical situations identified by majority shows that all civil parishes registered red cells in one or more indicators. the indicators unemployment rate (%) and school drop-out (%) encompassed almost half of the civil parishes marked in red ( out of ). the number of red cells per civil parish in the matrix also varies widely, from only one in the civil parish estrela to in beato ( . % of all indicators). figure shows that the geographical distribution of critical situations is not homogeneous across civil parishes and across the eight intervention axes. almost all civil parishes ( out of ) present critical situations within built environment axis (in one to nine indicators). in contrast, within lifestyles and health behaviours, here measured by one indicator (live births from overall, the higher number of critical situations is concentrated in the eastern part of the city (civil parishes of beato, marvila, penha de frança) and in the historic city centre (santa maria maior, são vicente, misericórdia) comprising neighbourhoods located along the tagus riverfront area. this is more evident in the following intervention axes: economic conditions, social protection and security, education, demographic change, built environment and healthcare resources and performance. the identification of critical situations within physical environment (mainly in the indicators of air pollution) and road safety (road traffic accidents) showed a different spatial pattern, being concentrated in the civil parishes located along the intersection of main roads and highways that traverse the city from north to south (e.g. eixo norte-sul) and from east to west (e.g. the °c ircular ring road). urban health indicator frameworks are considered useful tools with the aim of informing urban policy and decision-making. in this study, a place-based approach was applied to assess urban health inequities in the city of lisbon, using a spatial indicator framework together with a participation process. a total of local stakeholders, including city officials, participated in two workshops where they had the opportunity to discuss urban issues from a population health perspective and identify critical situations across the city. the main output is the generation of a matrix of health determinants that are deemed representative of existent inequities across eight intervention axes (critical situations reflect the indicators and the geographical areas with worse performances). together, these indicators, disaggregated at the parish scale, provide a picture of inequalities that should be addressed by local policies and interventions in order to promote equity in the city of lisbon. critical situations were identified in indicators covering a wide range of health determinants (e.g. unemployment, early school leaving, older adults living in social isolation, air pollution, noise exposure, inadequate housing conditions, road accidents involving pedestrians). the intervention axis of built environment was found to have the highest number of critical situations (cells were marked red in indicators and civil parishes) mainly reflecting poor housing and building conditions (e.g. households without central heating, buildings without wheelchair access, buildings in need of major repairs or very run-down) that persist in many civil parishes of lisbon. similarly, concerns related to urban mobility and transportation within the city were highlighted. a total of civil parishes were marked as critical due to low percentages of the population using public transportation and soft modes of mobility (e.g. walking, cycling). this confirms the need to change the existing mobility paradigm to a more sustainable one, which is already an expressed priority of the lisbon city government for the next decade. overall, several civil parishes systematically perform worse in most of the indicators of health determinants (accumulating critical situations) when compared with the others, making these neighbourhoods a priority for intervention. the eastern part of the city (civil parishes of marvila and beato) and certain neighbourhoods in the city centre are characterized by higher rates of socio- material deprivation and are home to vulnerable populations, such as older adults living in poor housing conditions or social isolation. furthermore, the indicators of unemployment and school drop-out were considered critical issues across a considerable section of the municipality (in out of civil parishes). these indicators are a reflection of the deterioration of socioeconomic conditions driven by the - economic and financial crisis that hit portugal and, in particular, lisbon. addressing socioeconomic and educational inequities, namely employment and education, were considered by stakeholders as key to promoting health and equity. this study presents a general framework to assess urban health inequities, useful to identify priority issues and neighbourhoods needing policy intervention. the indicators identified as critical situations for health equity are from diverse intervention axes, linked directly to the action of many municipal departments and dependent on place-based interventions (e.g. reducing pollution, improving housing, territorial and social cohesion, urban design, mobility). the indicator framework described in this study present a number of characteristics that are considered by pineo and colleagues [ ] as facilitators to the use of urban health indicators by local government: (ii) neighbourhood-scale data; (iii) indicators from social and built environment; (iv) local and diverse knowledge are incorporated via a participation process [ ] . the interconnectedness among those situations identified as critical serves to reinforce the need for an integrated approach to urban health in lisbon and the implementation of a health in all policies (hiap) strategy [ , ] . in the words of the local city councillor for social rights, "this case study highlighted the link between health determinants ( a s s e s s m e n t ) a n d po l i c y a c t i o n ( r e s p o n s e ) , emphasizing the role that non-healthcare sectors (from social assistance to urban planning to housing) have on promoting health equity". in portugal, the responsibility for public health is a very centralized, one that to a large degree still remains in the hands of the health sector through regional health administrations. additionally, the use of participation processes in local decision-making is considered modest with a deficit of stakeholder engagement and intersectoral work. integrating health equity in all policies, specifically into local plans, requires an effective political will and commitment as key elements to act upon the causes of health inequalities at the municipal level [ ] . the recent decentralization of competences to municipalities and inter-municipal associations (law / , january ) endowed local governments with a more formal health mandate and can offer space to design effective policies addressing population health needs. within the scope of new competences, municipalities are responsible for developing a municipal health plan, a strategy document that contains a comprehensive picture of municipal health issues, priorities and plan for actions. this study can provide a basis for developing the municipal scan (first stage of the planning process), providing a place-based and context-specific approach to population health, focusing on multiple determinants of health inequities and on how they are distributed among city neighbourhoods. a good understanding of determinants of health outcomes, together with evidence on their geographical inequalities, are vital to informing decisionmaking at multiple levels (at the civil parish, municipal and metropolitan levels) and to orientating the prioritization of critical issues to address [ ] . the participation of different groups of stakeholders (local and regional government, charities and other nonprofit associations and ngos, public health and healthcare services) working in the municipality and in varied fields of intervention contributes to raising and (b and c) . a consultation material. b workshop . c workshop awareness on the importance of implementing intersectoral and interinstitutional action [ ] . overall, at the end of the workshops, stakeholders stated that they gained new insights and broadened their views on while they recognized this participatory process as very important to initiating a dialogue and leveraging intersectoral action targeting the identified urban health issues, it may not be effective by itself in the process of influencing decision-making to change the status quo of health inequalities within the city. there is no great tradition in portuguese municipalities to conduct participation processes with local stakeholders, and intersectoral action for health still lags behind in comparison with other countries. for example, city departments work in silos and do not collaborate very often. to our knowledge, this was the first participation and collaborative process on urban health and related inequities to take place in lisbon, here understood through the lens of sdoh and hiap approaches. youth neither employed nor in education or training (neet) (%) homeless people (n°) people receiving social integration subsidies (number per active population) ( out of ) school drop-out rate (%) demographic change ( out of ) older adults living alone and in social isolation (%) older adults reporting limitations/disabilities (%) older adults living in buildings with floors or more without elevator (%) lifestyles and hbs ( out of ) live births from adolescent mothers (age under ) (%) physical environment ( out of ) particulate matter (pm ) concentrations (μg/m ) population exposed to noise levels greater than lden db (%) population potentially affected by flooding (%) built environment ( out of ) overcrowded housing (%) households without central heating (%) buildings without wheelchair access (%) buildings in need of major repairs or very run-down (%) walkability index average walking distance to the nearest adult day-care centre (minutes) average walking distance to the nearest sports facility (minutes) capacity after the case study of lisbon, the research team continued to collaborate with the city council, extending this study to the field of policy analysis and prioritization using participation processes with the same group of stakeholders. in , two participatory processes were organized in which city departments, civil parishes and local stakeholders from multiple sectors engaged with the topic "intersectoral action to promote urban health equity in lisbon". however, changes in the governance structure and policymaking process that incorporate health equity considerations in city plans are dependent upon strong political will and commitment. fig. geographical distribution of identified critical situations by intervention axis, in the municipality of lisbon. note: civil parishes are coloured using a monochromatic colour scheme with a gradient ranging from light red to dark red according to the number of indicators identified by the majority as a critical situation. civil parishes in light red were marked as critical in less than % of the indicators selected in the intervention axis. civil parishes in dark red were marked as critical in more than % of the selected indicators. civil parishes in white were not marked red for any indicator of the intervention axis. political conviction and extended governance, including the involvement and participation of practitioners and citizens in the evaluation and selection of policies, are critical in the city's efforts to move towards achieving urban health equity. this topic will be explored in a subsequent paper analysing which municipal policies have the greatest potential to reduce urban health inequalities in lisbon in light of the evidence gathered in this study. a list of policies and actions addressing the identified critical situations (indicators and civil parishes) was produced and analysed in consideration of their overall benefit to reducing inequities in each intervention axis. finally, the current global challenge to health equity, posed by the covid- pandemic, places greater urgency in the analysis of current sdoh inequities at the local level. covid- , and the wider governmental and societal response, have brought existing health inequalities into keener focus [ , ] . the emerging debate on the pivotal role of local government in addressing the virus outbreak includes recommendations to integrate responses tailored to the local context and oriented to neighbourhoods with worse health determinants (e.g. overcrowded housing, poor sanitation, socioeconomic deprivation, lack of green spaces, poor access to healthcare). this study could provide a basis for adopting a place-based and territorially sensitive approach to prioritize those neighbourhoods in most need, as well as to inform intersectoral action and collaborative work across municipal departments and public health stakeholders in the city of lisbon. the methodology used can provide input that informs local plans and strategies. the use of area-level indicators was an efficient means of analysing existing variations in health determinants and identifying those neighbourhoods that need to be prioritized [ , , ] . a simple indicator matrix combined with a convivial workshop protocol offered an integrated, transparent and comprehensive way of examining urban inequities, by including indicators from different intervention axes and area-level data at the civil parish scale. the material for consultation provided during the workshops in the form of maps and indicator's identity card (together with indicators of health outcomes) allowed stakeholders to better understand how the unequal distribution of health determinants across lisbon is potentially contributing to health inequities. stakeholders had the opportunity to analyse the overlapping pattern between worse performances in health determinants and worse performances in health outcomes. the workshop format provided face-to-face interaction enabling the participants to work in small groups thus affording them a space for the in-depth exploration of indicator data and the exchange of points of view and perspectives, not all of which were perfectly concordant. at the beginning of the workshop, the research team presented the assumptions and principles followed in the design of the exercise. the aim was to introduce the objective of the exercise and guide the assessment towards the identification of critical situations in each intervention axis to inform decision-making and future prioritization. the assessment was carried out across eight independent intervention axes, meaning that stakeholders worked each intervention axis independently and did not prioritize one above the other. the research team acted as facilitators in the group discussion, providing clarifications on the consultation material and helping to keep participants engaged and focused on the aim of the workshop, allowing all voices to be heard and leaving participants willing to engage in further discussion. the role of the research team was not to influence the results but to create the environment for effective communication so both disagreement and mutual understanding could surface. in the group discussion phase, each participant had the opportunity to present their own opinions on indicators. by asking stakeholders to review and discuss the final matrix, mistakes and instances of underreporting were detected and clarified. overall, participants showed agreement on the list presented, stating that the list was very comprehensive, already integrating enough determinants from a wide range of relevant dimensions to assess lisbon urban health. the assumption of "outputs validity" was reached [ , ] : stakeholders acknowledged that the results are accurate, clear and transparent and provide a comprehensive picture of the equity problems the city is facing. the preliminary matrix of indicators was built with measurable variables, reflecting the status quo of an urban community (civil parish) generated through valid and available data from official statistics. one of the criteria underlying a good indicator framework informing a place-oriented intervention to urban health equity is exhaustivity, that is, indicators which measure different health determinants (all eight intervention axes had to include one or more indicators) and allow for monitoring inequality across time and space. similar to other urban health assessments reported in the literature [ , ] , the availability of data disaggregated at the parish level was considered paramount in the case study of lisbon although it also offered some barriers. a specific limitation was data collection at the parish level for some very relevant indicators to assess urban health equity, such as household income or cost of housing. in recent years, the access to affordable and adequate housing, linked to the growing gentrification taking place in many neighbourhoods, is considered the main issue affecting urban equity in lisbon and is currently a top priority in terms of policies reflecting social justice. at the time this study was being developed, there was no information available and reliable on this topic at the parish level. additionally, participants claimed the need to include lifestyles and health behaviours in the assessment (e.g. alcohol and tobacco consumption, physical activity levels, diet). yet, they immediately recognized the data constraints regarding the availability of these indicators at the local level. this case study does not prescribe a specific approach or set of indicators for use on every urban health assessment. in fact, current frameworks or indicator's systems of urban health differ substantially, reflecting the diversity of purpose [ , ] . however, there is some homogeneity in terms of the domains or dimensions of analysis. indicators used in the lisbon case study can be identified as examples of indicators of relevance to urban areas such as those relating to socioeconomic conditions and physical and built environment. as an example, similarities can be found with the who urban health equity assessment and response tool-urban heart, where the urban health assessment departs from an indicator matrix with data disaggregated at the neighbourhood level [ ] . establishing a framework for indicators should be meaningful for the context and city, using locally available data, to effectively address the needs of each neighbourhood. promoting health equity is a place-based issue. this study, by integrating local data in combination with a participatory process, pinpoints the added value of a context-specific and place-based approach for assessing urban health inequities. the use of indicator matrices and maps made it possible to see-in a simple, transparent and comprehensive way-geographical variations on multiple determinants of health across eight intervention axes considered relevant to promote health equity. evidence of these patterns supported stakeholder's analysis on what health determinants are shaping local health inequities and where (in which civil parishes) action is urgent. the results show that some civil parishes systematically perform worse in most of the indicators when compared with the others, thus becoming a priority for intervention. critical situations were identified in indicators covering a wide range of health determinants (e.g. social and economic, built and physical environment) linked to the action of many municipal departments and ones that can be addressed by city plans. the participation process created a collaborative environment, offering opportunities for researchers, policymakers and practitioners to engage in dialogue and co-learning on the importance of assessing and monitoring urban health through neighbourhood-level health determinants. finally, this study could provide a basis for adopting a place-based and territorially sensitive approach to prioritizing those neighbourhoods in most need, as well as to inform intersectoral action and collaborative work across municipal departments and local stakeholders in the city of lisbon. homem gouveia and teresa craveiro; civil parish council: maria capitolina marques; regional coordination and development commission scml): filomena gerardo, maria luís calinas and noémia silveiro; médicos do mundo (doctors of the world): fernando vasco marques; diabetes portugal (portuguese diabetes association-apdp): rogério ribeiro alzheimer portugal (portuguese alzheimer's association): ana sofia gomes and filipa gomes; observatório -luta contra a pobreza na cidade de lisboa (lisbon observatory for the european anti-poverty network-eapn): catarina cruz; the directorate-general of health (dgs/national health plan): rui portugal faculty of medicine of the university of lisbon (fmul): paulo nicola; primary health care fátima quitério; primary health care center group of western lisbon and oeiras (aces lisboa ocidental e oeiras): fátima nogueira and rafic nordin. finally, we would like to thank our english language reviewer grant agreement no , and received support from the centre of studies in geography and spatial planning (cegot), funded by national funds through the foundation for science and technology (fct) under the reference uid/geo/ / . angela freitas is a recipient of an individual doctoral fellowship funded by national funds through the foundation for science and technology (fct), under the reference sfrh/bd/ / . references . who and un-habitat. hidden cities: unmasking and overcoming health inequities in urban settings global report on urban health: equitable, healthier cities for sustainable development atlas of population health in european union regions population health inequalities across and within european metropolitan areas through the lens of the euro-healthy population health index healthy city planning: from neighbourhood to national health equity global report on urban health: equitable, healthier cities for sustainable development closing the gap in a generation: health equity through action on the social determinants of health. final report of the commission on social determinants of health. geneva: world health organization inequities in the freedom to lead a flourishing and healthy life: issues for healthy public policy urban place 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and multi-attribute value theory: an integrated approach for policy support value assessment frameworks for hta agencies: the organization of evidence-informed deliberative processes. value health getting stakeholder participation "right": a discussion of participatory processes and possible pitfalls promoting population health and equity in europe: from evidence to policy advancing tools to promote health equity across european union regions: the euro-healthy project promoting population health and equity in europe: from evidence to policy using the macbeth socio-technical methodological approach to build the euro-healthy phi indicators for evaluating european population health: a delphi selection process a socio-technical approach for group decision support in public strategic planning: the pernambuco ppa case scenarios for population health inequalities in in europe: the euro-healthy project experience devising and testing a novel methodology for the evaluation of policies under european population health scenarios closing the gap in a generation pope j selecting health indicators in population health: notes on choosing health indicators for the national biomedical risk factor survey. adelaide docman&view=download&category_slug=health-analysismetrics-evidence- &alias= -health-indicatorsconceptual-operational-considerations- &itemid= &lang=en the experience of implementing urban heart barcelona: a tool for action enhancing knowledge construction processes within multicriteria decision analysis: the collaborative value modelling framework the corsini encyclopedia of psychology quality criteria of the international collaboration for participatory health research use of urban health indicator tools by built environment policy-and decision-makers: a systematic review and narrative synthesis health in all policies: from rhetoric to action introduction to health in all policies and the analytical framework of the book the experience of implementing urban heart barcelona: a tool for action mapping environmental inequalities relevant for health for informing urban planning interventions-a case study in the city of dortmund, germany health equity and covid- : global perspectives the covid- pandemic and health inequalities acknowledgements the authors would like both to acknowledge the support received from the municipality of lisbon (cml) and to express gratitude for the opportunity to work with the city of lisbon in a case study. namely, the authors sincerely thank joão afonso (city councillor for social rights between and -cml/pds), teresa craveiro and her team (municipal health and wellbeing plan of lisbon-cml/ep-plhds) for the active involvement and support provided throughout the case study, namely in the preparation of workshops and support given on data collection. the authors are also grateful to the investigators involved in the preparation of the consultation materials that informed the workshops (indicator's identity card, tables and maps), namely adriana loureiro, claudia costa, ricardo almendra and joaquim patriarca from the university of coimbra and investigators involved in the design of the overall methodological approach of the euro-healhy project, namely paulo correia, carlos bana e costa and mónica oliveira from the instituto superior técnico, university of lisbon.then, we would like to gratefully acknowledge the participation of all local stakeholders involved in the participatory process (see list of institutions/participants below). disclosure statement the authors declare that they have no conflict of interest. key: cord- -aiq ejcq authors: acuna-zegarra, manuel adrian; comas-garcia, andreu; hernandez-vargas, esteban; santana-cibrian, mario; velasco-hernandez, jorge x. title: the sars-cov- epidemic outbreak: a review of plausible scenarios of containment and mitigation for mexico date: - - journal: nan doi: . / . . . sha: doc_id: cord_uid: aiq ejcq we present here several variants of a mathematical model to explore three main issues related to sars-cov- spread in scenarios similar to those present in mexico and elsewhere in latin america. we explore the consequences for travel inside a given region, in this case mexico, particularly focusing on airplane transportation but attempting to give a gross approximation to terrestrial movement since this is the main form of population movement across geographical areas in the country; then we proceed to study the effect of behavioral changes required to lower transmission by lowering the contact rate and infection probability and lastly, we explore the consequences of disease spread in a population subject to social isolation.these models are not suitable for predictive purposes although some rough predictions can be extracted from them. they are presented as a tool that can serve to explore plausible scenarios of spread and impact, effectiveness and consequences of contention and mitigation policies. given the early stage at which the epidemic is at the date of writing in mexico, we hope these ideas can be helpful for the understanding of the importance of isolation, social distancing and screening of the general population. at the end of december of a novel coronavirus sars-cov- , was detected in adults with pneumonia from the city of wuhan, hubei province, china. this new virus rapidly spread from hubei province to all china [ ] [ ] [ ] [ ] [ ] . by january th the virus was detected in south korea, taiwan, thailand. macao and usa. by march of , , cases of new virus have been detected in countries and % of the cases has been register in continental china. in february , brazil was the first country of latin america to detect this virus and mexico detect his first case one day later [ ] . covid- is a respiratory disease caused by the sars-cov- virus, that has been widely studied in these recents weeks and we defer its description to the appropriate sources e.g. [ , ] . the disease has been extensively modeled as a seir type of epidemic. in this work we use the seir model framework adapting it to the particular set of problems addressed here. in each section, dependent on the model variant used, we introduce the new parameters if any and refer to the appropriate section in the appendix for the specific model equations. the rate ω or the related time /ω is the mean time of application of non-pharmaceutical interventions (npi). all the recommendations that are being advised to prevent infection affect behavior (washing hands, keeping cough/sneeze etiquette, avoiding handshakes, keeping distance from other people) and, therefore, have a learning curve and can be forgotten or relaxed or incompletely adopted in any given population; also q is the proportion of the population that is effectively put under isolation. for example, in wuhan, about % of the population was put under isolation. the total population normally living in that region is of about million but the population at risk was obviously larger comprising much of the hubei region. the incubation and infectious periods have been a most important issue in the present epidemic and estimates have varied as more information is available on the dynamics of the disease. we will use incubation period /γ = days [ , [ ] [ ] [ ] . the same situation occurs with the infectious period that we take /η = days [ , , ] . one of the first articles to calculate the basic reproduction number r of the new coronavirus in wuhan china, estimated (jan , ) its value as . ( . − . ) with an epidemic doubling time of . days ( . − . ) [ ] . other authors have estimated the basic reproductive number to be around . , value that we use here for the wuhan original outbreak but again there exist some variability and uncertainity in the different estimates [ ] [ ] [ ] [ ] [ ] [ ] . in what follows some simple models are described related to three specific situations described above and occurring during this epidemic: disease dispersion due to long range population movement, behavioral change imposed on individuals as an strategy of containment, and the effect of social distancing on the general fate of the epidemic. we analyze the cumulative trajectory of covid cases in mexico in order to create short-term real-time forecasts of the outbreak. the data consists of daily cumulative cases from february , to march , . the data was obtained daily at : p.m. (gmt- ) from the secretariat of health press conferences. to create the forecasts, we use richards model which considers that cumulative cases c(t) are given by where r represents the growth rate of infection, k is the carrying capacity (or final epidemic size, and a is a scaling parameter. this model is an extension of the simple logistic growth model that has been recently used to predict cumulative covid cases in china [ ] . parameters a, r and k must be estimated in order to properly describe the observed data and to provide accurate forecasts. we use an statistical approach through bayesian inference. details regarding the estimation procedure and the the results can be found on appendix a. the growth rate r is close to . and it can range from . to . with a probability of %. however, the total size of the outbreak k is more difficult to estimate which is expected since mexico is at the start of the outbreak and the current data . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . shows that the contagion is accelerating. we estimate the final size of the outbreak to be , cases, ranging from , up to , , with a probability of % provided no cotrol/contaiment/mitigation measures are applied. these are very long-term predictions and that is why there is too much variability in the interval. to estimate the parameters we used data up to march , . the last two available observations corresponding to march and can be seen in figure , and are closely predicted by the fitted model. furthermore, we create days predictions from march , to april , which can also be seen in figure . for example, at march , , the model expects , cases, with a % probability interval of ( , ); and at april , , a total of , cases are expected with a % probability interval of ( , , , ). table shows the median posterior estimates for each parameter and % probability intervals. figure shows the marginal posterior distributions estimates for each parameter. finaly, using the same data we estimated the basic reproduction number for the whole country. we use the package written in r, estimation of r and real-time reproduction number from epidemics (https://cran.r-project.org/package=r ) using the exponential cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint and maximum likelihood methods. we obtained using the exponential growth method r = . ( . , . ); and using the maximum likelihood r = . ( . , . ). given that for the richards curve, the growth rate for mexico is r = . below of that of the wuhan epidemic, see table , we use the estimate from the maximum likelihood method that renders r = . with an uncertainity interval of ( . , . ). in what follows we use several mathematical models to explore the consequences of interventions on the spread of the disease, i.e., how interventions modify the worrisome picture depicted in figure . the mexico city airport is one of the main connections hubs of latin america and the country, and therefore arrival of covid cases has occurred. in this section, we use data on the daily number of domestic and international travelers that arrive/leave to/from the mexico city airport [ ] . below we follow the ideas presented first in [ ] . we construct an standard seir kermack-mckendrick mathematical model (see appendix b) where s, e, y a , y s and r represent susceptible, exposed, asymptomatic infectious, symptomatic infectious, and recovered (immune) individuals. n is the total population. the force on infection is (β a y a + β s y s )/n . we consider that symptomatic individuals have restricted movement since either they are too sick to travel or are immediately detected by the health services at the airport or elsewhere. this consequently decreases their overall contact rate β s compared to that of an asymptomatic individual β a . therefore β s < β a throughout this section. following [ ] we define two rates related to the inbound number of international air passengers to mexico city (l im ), and the inbound number of national of both airplane and terrestrial passengers to mexico city (l sm ). the basic model is shown in appendix b as the main objective in this section is to study the consequences of disease importation to a large latin american city, we assume first that a proportion of the international air passengers arrive as disease carriers. we define ρ t to be the proportion of international air passengers at time t who cannot transmit the disease, e.g., if ρ t = . then % of the international air passengers are infectious. of these carriers, a proportionq arrive as exposed not yet infectious individuals and −q arrive as asymptomatic infectious individuals. l ms and l sm are functions of time describing travelers either arriving to mexico city airport of leaving mexico city airport. these rates are time dependent since we eventually take into account the increase on the number of national travelers during holiday periods, specifically holy week in mexico. for the analysis we perform a normalization in order to work with proportions and not absolute numbers of individuals (see ( ) , appendix c). one of the goals of this manuscript is to study the arrival of covid to mexico city and its plausible patterns of propagation. the timeline of our study is half a year. to estimate the daily average number of national and international inbound/outbound air and road travelers, respectively we employ information from the secretariat of communications and transportation (sct) [ ] and the general directorate for tourism competitiveness of mexico city [ ] . the timeline is set to include holy week, a short holiday which normally presents an increase of arrival/departure flights to/from mexico city. on the other hand, the main transport means of the mexican population is by far terrestrial by bus. unfortunately, we only have data on the number of bus passengers outbound from mexico city, reported by the large bus terminals norte, sur, poniente and oriente. we will assume that on average the number of bus passengers that arrive to mexico city is greater than those that leave. for our simulations, we employ flight data for february , terrestrial data for january / and take february st as the initial date of the arrival of the first cases. this estimate is plausible since the first cases in mexico were reported on february th but given that the incubation period is of days they likely arrived to mexico city on february st or nd. we also set the population size of the greater metropolitan area of mexico city at inhabitants. to estimate the inbound/outbound international travelers migration rates, we take into account all flights that arrive/leave mexico city [ ] . thus, the daily average number of international arrival and departure air travelers are l im = , and l mi = , , respectively. see appendix g for the procedure followed to give this estimates. to estimate the inbound/outbound national travelers migration rates we integrate air and terrestrial transportation. for national flights we arbitrarily select the thirteen more important destinations from mexico city, i.e., those who have more passengers inbound leaving from mexico city. on the other hand, to estimate the number of terrestrial passengers, we use data from the above mentioned four main bus terminals of mexico city. therefore, we calculate the averages per day of national passengers in both kinds of transport (airplane and bus). thus l sm = , and l ms = , except during the holy week (for more details see appendix g). for the holy week (april th to april th), we proceed to increase previous estimates by % which is a rough and conservative approximation based on data from the secretariat of tourism [ ] . therefore l sm = , and l ms = , during this period and also the information available on the main bus terminals of mexico city (for further details see appendix g). finally, the incubation and the infectious period are set to γ = / and η = / per day, respectively. also, since we do not have data on the air passenger percentage that arrives in the latent or asymptomatic stage, we propose as a plausible valueq = . as a null hypothesis from which to start our analysis. for our first case, we assume ρ t = . that is mexico city airport received only one imported case per day (ipd). figure shows that the higher the proportion of asymptomatic infected arriving two things happen: the outbreak occurs earlier and also the peak of the outbreak is higher. in table , we further illustrate this case. notice that . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . . the changes in prevalence at different dates when proportions of asymptomatic infected is increased. for this model we explicitly calculated the basic reproductive number since it depends on ρ the proportion of asymptomatic infectious individuals, and explore the consequences of taking ρ = . , . and . , or, equivalently, r = . , . and . , respectively. these values are within the range reported by several authors and our own uncertainity interval (section ) [ , , ] . in our second case, we explore the effect of we explore the effect of decreasing ρ t which is equivalent to increasing the number of ipd. figure shows that for a higher number of ipd generates an earlier outbreak but the maximum of the outbreak does not change. in table , we further illustrate this case for mexico city. once again we observe that prevalence changes when increasing the number of ipd. this case is set by assuming that % (ρ = . ) of the infected people are asymptomatic giving r = . . we remark that if we simulate both cases in (figures - ) for a longer period of time, we can detect the existence of another epidemic outbreak as has already been noted [ ] . . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . . figure shows the expected number of exported cumulative cases (until april st) to several of the mexican cities that normally receive the highest outbound air or road travel volumes. here, as ρ = . , r = . . figure (a) shows the expected number of exported cumulative cases that use air travel. when considering one ipd, we see that few states receive at least one exported case from mexico city (cancun, guadalajara and monterrey). on the other hand, with three ipd, these states import , and cases from mexico city, respectively. figure (b) shows the exported cumulative cases for terrestrial transportation. here, if the imported cases per day (ipd) is one, then puebla, jalisco, michoacan, guerrero, and queretaro import , , , and cases up to aril st from mexico city, respectively; while if ipd is equal to three, then puebla, jalisco, michoacan, guerrero, and queretaro import , , , and infections from mexico city, respectively. figure shows the expected number of exported cumulative cases to several mexican cities. we simulate the number of cases until april st. we can observe the importance of the number of people who arrive infected since these can significantly increase the spread of the disease to other states. for example, figure (a) shows that for cancun, the number of exported cases can increase by cases if instead of ipd, we have ipd. for monterrey the increase, under the same conditions, is approximately cases. figure (b) shows a greater increase in cases for terrestrial than for air transportation. for example, we expect . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . finally, it is an obvious conclusion from our simulations that it is very important to control the number of people who arrive infected since these can significantly increase the spread of the disease to the other states. note that the results in this section do not include any control, mitigation of containment strategy. the results shown in tables - are some . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . table : mexico city prevalence (number of cases) for different days as a function of ipd (imported cases per day) under the assumption that % of cases end up as asymptomatic. once the disease arrives into a given region, city, or municipality, containment measures are at first, limited to behavioral changes called non-pharmaceutical interventions or npis, directed essentially to diminish transmission by reducing contact between people. in order to model this, we modify system ( ) to include a variable contact rateβ k (t), and omit migratory phenomena (see appendix d for the model equations). our main results in this section explore the variation of the effective contact rate under these actions. we definê where k = a or s for asymptomatic or symptomatic individuals, respectively. note from the formula above that we assume that behavioral change geared to diminish the contact rate from β k to q β k takes a learning time θ to acquire where q is the desired proportion of reduction of the initial contact rate, e.g., q = . if the contact rate is reduced in % at the end of a time interval of length θ. moreover, these control measures are not taken immediately after the outbreak is identified but lag a certain time t θ before being enforced or (see figure ) . the baseline parameters for the simulations that follow are β a = . , β s = . , γ = / , η = / , ρ = . , . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . where, we remind the reader correspond to the contact rates of asymptomatic and symptomatic infecteds, the incubation and infectious period and the proportion of asymptomatic cases respectively. figure illustrates the behavior of the contact rates for asymptomaticsβ a (t) and for symptomaticsβ s (t). for both rates, the efficacy of education on the behavioral change is the same since we assume that education is not related to symptomatology although there is some evidence that this might not be the case. a first result is that if the time it takes to obtain the desired contact rate reduction θ increases then the reduction rate of both contact rates is slower. show that if the time it takes to achieve a reduction in contact rate increases then the number of infectious cases is greater reflecting the slow rate of behavioral change. figure a) and b) show the prevalence and cumulative incidence respectively, for an scenario with a target reduction of contact rate of %, the initiation of the behavioral change is t θ = days after cases are detected and where % of those are asymptomatic. for comparison, a red dashed line shows the epidemic curves when no behavioral change is enforced. here we see that although the reduction of contact rate is low ( %) (q = . ), in the long run behavioral change helps to reduce the incidence. we also note that in addition to the reduction in cases, as the time to achieve the contact rate reduction increases, the epidemic outbreak starts earlier and is larger. figure shows the behavior of the prevalence (a) and cumulative incidence (b) when the contact rate is reduced by % (q = . ). in this situation the relevance of the behavioral change to reduce the incidence is rather clear. notice that if the time necessary . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. to achieve the contact rate reduction is either θ = or θ = days (differing for more than two months), the outbreaks are very similar which makes us postulate the existence of a threshold value θ * such that the peak incidence is reduced if θ < θ * . larger learning times do not have an impact on the size of the epidemic. figures - show examples of the behavior of the cumulative incidence (at days after infected are detected which we use as the indicator of initiation of the outbreak in this example) as a function of certain parameter values. figure shows that if t θ is closer to the time of detection of the first cases (in this example, when infected people are detected), then the cumulative incidence can be reduced more efficiently and underlines the importance of reducing the effective contact rate quickly. in our example even when the reduction is only of %, we see that the final cumulative incidence decreases to low levels. this observation contrasts with what is shown in figures and . we will discuss this in more detail later. on the other hand, figure (b) shows that even when the time it takes to get the contact rate reduction is large (θ = days), we can still recover a large reduction in the final cumulative incidence provided we have a quick response to enforce reduced contacts and a large target reduction in the effective contact rate. figure shows that when t θ = days, regardless of the time θ it takes to obtain the contact rate reduction, the final cumulative incidence is very low for large reductions in contact rates (q small) or high for low reductions in contact rate (q large). to finish this section, we remark that figure figure : (a) cumulative incidence for varying θ, the learning time to achieve the target reduction and t θ , the delay to start behavioral change for a fixed reduction of contact rate of %, and (b) cumulative incidence for varying t θ , the delay to start behavioral change and q the target proportion of reduction of the contact rate for a fixed time to obtain the target contact rate of days. reducing the contact rate for flattening the epidemic curve. on any scenario, a large reduction of the effective contact rate is necessary (figure (a) ). figures (b) shows an . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. if the epidemic cannot be contained, social isolation has been implemented in many places of the world, notably in china where, given the extent and strictness of its enforcement, it has apparently been successful. we modify our model to incorporate this containment measure and let s, e, y a , y s and r as usual represent susceptible, exposed, asymptomatic and symptomatic infectious and recovered (immune) individuals in isolation which occurs when a proportion q of the general population is put on restricted movement. the population . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint not under isolation (i.e., a fraction −q of the total) is denoted by the letters c s , c e , c ya , c ys and c r for susceptible, exposed, asymptomatic and symptomatic infectious and recovered (immune) individuals. in this model isolation comprises not only physical isolation, but also the enforcement of sanitary and preventive measures like frequently washing hands, use of face masks, avoiding of public gatherings and so forth. the actual physical isolation depends on many factors, particularly the length of the incubation period of the virus but many of the preventive measures taken by individuals and groups of individuals can last much longer. the isolation enforcement has the following modeling set up. after the first appearance of the virus a seir epidemic starts and develops until time t θ where quarantine and isolation are enforced and a fraction q of individuals in the population goes into isolation. we define q to be the efficacy of isolation, e.g., q = . if % of the population is isolated. we then record the number of people in each of the seir compartments at t θ , and use these numbers as the initial conditions for the state variables of the same seir epidemic but under isolation starting at t θ . the subsystem that escaped or that was not put under isolation we denote by cseir. we also assume that isolation measures are not perfect and individuals escape from isolation regardless of infection status at an exponential average time of /ω and also that individuals suspend, forget or relax sanitary measures at the rate ω. it is also assumed that the isolation time is always larger than the total time of duration of disease comprising the incubation time, /γ, and the infectiousness time /η. therefore /ω > /γ + /η. we further assume that a fraction ρ of the exposed individuals develop the asymptomatic disease and that − ρ become symptomatic. the contact rates before isolation is enforced are β i a and β i a for symptomatic and asymptomatic individuals. following the ideas set in the previous section we define two time-dependent contact rates for the isolated population that can be consulted in appendix d. the natural mortality and recruitment rates respectively are assumed to be negligible during the time of the epidemic. with these definitions the model can is shown in appendix e. in summary, for t < t θ the infectious disease is the standard seir kermack-mackendrick model. once t = t θ is reached, the population is divided into the isolated and non-isolated sections with contact rates ( ) and ( ) respectively. to calibrate our model, in this section we characterize the epidemic in wuhan, china (epicenter of the first epidemic outbreak) [ ] . we introduce an isolation stage and the consequent reduction in the contact rates. for wuhan the basic reproduction number has been estimated to be r i = . [ , , . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint η = / , ρ = . , ω = . , q = . , q = . . figure shows the contact rates for the isolated environment. for both rates, the reduction of contact is % (q = . ), the day of initial isolation is january th. we can impose a fast behavioral change because we think that this process lasted a short time ( days) in wuhan. figure presents the case when the % of population is isolated. observe that the peak incidence is approximately individuals and it occurs days after isolation began (january th, [ ] ) figure (b) ). our simulations show that carrying out an isolation process promotes an earlier decrease in incidence. on the other hand, considering a total population equal to million [ ] the prevalence at the peak of the epidemic in wuhan is around cases which is a gross underestimate of the true observed value [ ] . a better estimate of the at-risk population in wuhan would, we believe, improve or estimate. figure shows a comparison of the estimated cumulative incidence (blue line) versus the data reported by the who (red cross) for the hubei province [ ] . our curves overestimate the data, which may be reasonable due the known under-reporting of cases and to the fact that initially there are fewer cases making it difficult to detect them. nonetheless we see that when the real epidemic curve begins to stabilize, the difference between both data and model decreases, which can be explained if we accept that, at this stage, there are many more cases and it is easier to identify them. also under-reporting decreases for the same reason. the black point on the model cumulative incidence (blue curve) indicates the inflection point. the black dots over the red curve mark the range where the inflection point is located in the data. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . the mathematical model in this section is a different variant of the one we applied for wuhan because mexico city outbreak started with imported cases. therefore we retake the model proposed in section and combine it with the wuhan model of the previous section to incorporate isolation and behavioral change. in mexico air travel has been gradually suspended and at the time of writing (end of march) not all flights have been canceled. this implies that the flow of people from abroad is low but significative and it is arriving into a population that is not isolated but has started measures to reduce the contact rate (social distancing). the model is shown in . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . below we explore three scenarios that might occur in a large metropolitan that includes variation in the reduction of contact rates, variation in the time it takes to get the contact rate reduction θ and different dates for start de isolation t θ . as in section , we consider february as the initial date of infection, figures - show the behavior of the outbreak after and before isolation. on march rd authorities of mexico city ordered the closure of cinemas, theaters, and other public places as a preventive measure. we show in figure the incidence and cummulative incidence under reductions in contact rates of %, % and %, and for θ = days. our simulations show that for these reductions in contact rates, a reduction of up to % in incidence can be obtained. however, if we take the first weeks after the arrival of the first imported case, figure (b) shows that depending on the contact rate reduction, we could reach a similar situation to that of wuhan with total cases, (q = . ), or a medium level situation with total cases (q = . ) or a more manageable situation with total cases, (q = . ). figure shows the scenario for different θ, the time it takes to get the desired contact rate reduction. in this case isolation also begins on march rd and the reduction in contact rates is %. we observe that by increasing the value of this parameter, the peak and cumulative incidence will be higher. for example, if the time it takes to reduce the contact rates is θ = days, then the cumulative incidence weeks after the arrival of the first imported case will be , while if the time is θ = days, then the incidence rises to . finally, if the time it takes to reduce contact rates is days, then the cumulative incidence rises to . it is important to note that although the value of the cumulative . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . figure : (a) incidence and (b) cumulative incidence for the isolated population. the time to obtain the target contact rate reduction is days. black, red and blue lines correspond to reductions in contact rate of %, % and %, respectively. horizontal axis is time in days and the vertical axis is number of individuals. incidence increases, it does not happen with the same intensity as in the case shown in figure . . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint in our third case we explore variation in the time to start the isolation. here the time to reduce the contact rates is θ = days and the target reduction is %. the initial dates of isolation are: march rd (blue line), march th (red line) and april th (black line). the objective of this scenario is to asses what would happen if large cities start isolation and enforce behavioral change several days after this was done in the mexican capital. figure (a) shows the increase in incidence as the isolation start date increases. solid lines represent the situation before isolation and the dashed lines represent the situation after the start of isolation. figure (b) shows that if the onset of isolation had occurred one or two weeks after march rd, then by week , the cumulative incidence would increase by and new cases, respectively. this scenario underlines the importance of taking contingency measures with due anticipation, otherwise the number of infected people will notoriously increase. figure : (a) incidence and (b) cumulative incidence for the isolated environment. here we consider that the reduction of contact rate reduction is %, and the time it takes to get the contact rate reduction is equal to . blue, red and black lines mean that the dates for start de isolation are , and days after the first arrival of an infected individual to mexico city, respectively. horizontal axis is time in days and the vertical axis is number of individuals. the control, containment, mitigation and final resolution of the coronavirus epidemic requires careful consideration of alternative scenarios as pointed out very clearly in [ ] . models like the ones presented here can help decision-makers to have amore comprehensive understanding of the epidemic and thus a better set of criteria on which to base decisions. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . the models presented here are of the same general type that have been published and are being written elsewhere for the coronavirus epidemics. the coronavirus epidemic is an acute respiratory infection highly contagious and with a case fatality rate above of that for influenza. from the modeling point of view the kermak-mckendrick formalism is the basic and general mathematical tool to understand the epidemic at a population level. the conclusions that we can reach from the study that we have developed in the previous sections are the following: • restricting population mobility has been reported as highly effective for the containment of the initial covid- outbreak in china [ , ] . we have attempted to describe the present conditions in mexico to evaluate the consequences of delaying or advancing the enforcement of isolation and mobility restrictions putting special emphasis on the role of asymptomatic cases since these have been identified as probable important drivers of the disease [ , ] . at the start of the epidemic in mexico, figure shows that the higher the proportion of asymptomatic cases arriving two things happen: the outbreak occurs earlier and also the peak of the outbreak is higher. the role of asymptomatic cases has been under study in the literature particularly as their likely important role in driving the epidemic appears clearer. in our case, their impact is to generate an earlier outbreak and also a higher maximum incidence. • figure underlines the relative insensitivity of the peak incidence on the rate of importation of cases provided this rate is relatively low (up to cases per day). nonetheless, the higher this rate the earlier the outbreak goes into exponential growth (phase according to who criteria). we remark that running the simulations that (figures - ) ilustrate for a longer period of time, we can detect the existence of a second epidemic outbreak. with respect to disease spread at a national level in mexico, the importance of controlling the number of people who arrive infected to the larger airport hubs and bus terminals is of first priority since, not doing it, these can significantly increase the spread of the disease to the other states. • behavioral change is one of the main forms to reduce contact rates [ ] . however, when dealing with behavioral issues we enter into the psychological realm of individuals and groups of individuals. for our simulations we assume that education or awareness and rational decisions regarding the behavioral change associated with reducing contact rates is the same for asymptomatic and symptomatic individuals although there is some evidence that this might not be the case as one can directly witness. we assume different proportions of these two types of infected individuals. this is an open area of exploration that has not been pursued here. in any case, if asymptomatic individuals or any identifiable portion of the population have more "reckless behavior" on average than other individuals infected or not, then the expected incidence will be higher in any given scenario. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . • the policies of containment and mitigation have to be applied quickly, with no hesitation. we observe from our simulations that if the time it takes to obtain the desired contact rate reduction θ increases then the reduction rate of both contact rates, for asymptomatic and symptomatic individuals, flattens the curve but more slowly. we also note that in addition to the reduction in cases, as the time to achieve the contact rate reduction increases, the epidemic outbreak starts earlier and is larger. in the examples illustrated above, we see that if the time necessary to achieve the contact rate reduction is either θ = or θ = days (differing for more than two months), the outbreak sizes are similar which to us indicate the existence of a threshold value θ * such that the cumulative incidence is reduced if θ < θ * . in summary large learning times do not have an impact on the size of the epidemic. figure shows that if t θ is closer to the time of detection of the first cases (in this example, infected people), then the cumulative incidence can be reduced more efficiently and underlines the importance of reducing the effective contact rate quickly. figure (b) shows that although the time it takes to get the contact rate reduction is high (θ = days), we still can obtain a large reduction in the final cumulative incidence provided we have a quick response to enforce reduced contacts and a large target reduction in the effective contact rate. figure shows that when t θ = days, regardless of the time θ it takes to obtain the contact rate reduction, the final cumulative incidence is very low for large reductions in contact rates (q small) or high for low reductions in contact rate (q large). figure (a) and show the importance of reducing the contact rate for flattening the epidemic curve. on any scenario, a large reduction of the effective contact rate is necessary (figure (a)). figures (b) shows an example where an insufficient reduction of the contact rate ( %), leads to a very weak reduction on the final cumulative incidence. • figure shows the case when % of population is isolated. we can see that the peak incidence occurs days after isolation began (january th) indicating that the isolation process promotes an earlier decrease in incidence. this scenario underlines the importance of taking contingency measures with due anticipation, otherwise the number of cases will notoriously increase. • figure highlights the importance of beginning isolation early t θ = (march rd). our model indicates that delaying action by one or two weeks will let the outbreak grow with a significant increase in cases. figure shows, however, that isolation is not enough to lower the size of the outbreak but that a significant reduction in transmission rate is also needed. both control measures have to be applied simultaneously to be efficient in flattening the epidemic curve. we remark that simulations in both, are for a transmission rate reduction achieved in θ = days. figure shows that for longer times, the total number of cases will increase. all of the latter leaves the message that apart from designing and enforcing control . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . measures, the full participation of the society at large in the fight against this disease is extremely important. it is necessary to reduce the contact rate to a low enough level to be able to contain it, it is necessary to isolate, trace and test individuals. these actions require from everybody to be deeply aware of what should and should not be done to stop the spreading of the disease. let y j , for j = , , ...n, be the number of observed cumulative cases at time t j , with t j given in days. we assume that y j follows a negative binomial distribution with mean value c(t j |a, r, k) and dispersion parameter α. here, c(t j |a, r, k) is the solution of richards model presented in ( ) . assuming that, given the parameters, the observations y , y , . . . , y n are conditionally independent, then the negative binomial distribution allows to control the variability of the data by considering over-dispersion which is common for epidemiological data. if α = , then we return to the poisson model which is often used in this context. let θ = (a, r, k, α) be the vector of parameters to estimate. the inclusion of the parameter α, which is related to the variability of the data, not to the richards model, is necessary since in practice this variability is unknown. then, the likelihood function, which represent how likely is to observe the data under the negative binomial assumption and richards model if we knew the parameters, is given by π(y , . . . , y n |θ) = n j= Γ(y j + τ ) Γ(y j )Γ(τ ) τ τ + c(t j |a, r, k) τ c(t j |a, r, k) τ + c(t j |a, r, k) consider that parameters a, r, k and α as random variables. assuming prior independence, the joint prior distribution for vector θ is π(θ) = π(a)π(r)π(k)π(α), where π(a) is the probability density function (pdf) of a uniform( , ) distribution, π(r) is the pdf of a gamma(shape= , scale= ), π(k) is the pdf of a uniform(k min , k max ), and π(α) is the pdf of a gamma(shape= , scale= . ). to select the prior for parameter r, we consider that previous estimation of r are close to . [ ] , and a gamma( , ) represent a weekly informative prior as it allows for a wide range of values of r. also, there is no available prior information regarding the final size of the outbreak k. this is a critical parameter in the model and, in order to avoid bias, we assume a uniform prior over k min and k max . to set these last to values, we consider that the minimum number of confirmed cases is the current number of observed cases y (t n ) times nine, i.e. k min = y n * . the reasoning behind this number is that it has been suggested that the observed cases are under reported by a factor of nine (ref). to set the upper bound for k, we consider a fraction of the total population k max = n * . , where n is the population size of mexico. this fraction was determined base on the observations of other countries such as italy where the proportion of infected represents one of the worst case scenarios considering its population size. then, the posterior distribution of the parameters of interest is π(θ|y , . . . , y n ) ∝ π(y , . . . , y n |θ)π(θ), and it does not have an analytical form since the likelihood function depends on the solution of the richards model, which must be approximated numerically. we analyze the posterior distribution using an mcmc algorithm that does not require tuning called t-walk s [ ] . this algorithm generates samples from the posterior distribution that can be used to estimate marginal posterior densities, mean, variance, quantiles, etc. we refer the reader to [ ] for more details on mcmc methods and to [ ] for an introduction to bayesian inference with differential equations. we run the t-walk for , iterations, discard the first and use , samples to generate estimates of the parameters and short-term predictions for the next days. equations for the model reviewed in section . see main text for variables and parameter definitions. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint c national spread model equations for the model reviewed in section that includes transportation. for the analysis we standarize the model variables to work with proportions. we define the variables: thus, system ( ) becomes this model sets the migration functios l im = lmi = l sm = l ms = and µ = . thus with varying contact rates given as: with k = a or s for asymptomatic and symptomatic individuals, respectively. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . after isolation is enforced, we have a model for the isolated population and for the non-isolated population: c s = − β s (t)c ys +β a (t)c ya c s + ωx s c e = β s (t)c ys +β a (t)c ya c s − γc e + ωx e c ya = ργc e − ηc ya + ωx ya c ys = ( − ρ)γc e − ηc ys + ωx ys c r = η(c ya + c ys ) + ωx r ( ) with contact transmission for the non-isolated part of the population: where k = a or s for asymptomatic or symptomatic individuals, respectively.q is the desired proportion of reduction of the initial contact rate, e.g.,q = . if the contact rate is reduced in % at the end of a time interval of lengthθ. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted march , . dynamics before isolation is given by system . after isolation, dynamics for the isolated population is given by and dynamics for non-isolation is described by: . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . . to estimate the values of l im and l mi , we calculate the average number of passengers per day arriving/departing from mexico city from/to abroad taking the total number of passengers for each mean of transportation and divide it by the corresponding number of days. we use the data reported by the ministry of communications and transportation [ ] . from from table , the values of total air passengers that arrived and departure from mexico city in february are and , respectively. therefore, lim ≈ and lmi ≈ . the values of l sm and l ms outside the holy week are estimated similarly to the previous case from data from the ministry of communications and transportation (mct) and the general directorate for tourism of mexico city [ , ] . from table , the average number of passengers per day, outside the holy week air and terrestrial departing from mexico city are , and , , respectively. hence l ms = . proceeding in similar manner, the value of l sm is equal to . finally, to calculate the l ms and l sm values during holy week, we increased the above values by %. we chose this value because when averaging visits to the official sites of the ministry . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . conceptualization: maaz, jxvh. formal analysis and investigation: maaz, jxvh. performed statistical analysis: msc; wrote and discussed the paper: all authors. . cc-by-nc-nd . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted march , . . https://doi.org/ . / . . . doi: medrxiv preprint what to do next to control the -ncov epidemic clinical characteristics of hospitalized patients with novel coronavirus-infected pneumonia in wuhan, china nowcasting and forecasting the potential domestic and international spread of the -ncov outbreak originating in wuhan , china : a modelling study coronavirus infections-more than just the common cold a novel coronavirus emerging in china -key questions for impact assessment an interactive web-based dashboard to track covid- in real time incubation period of novel coronavirus ( -ncov) infections among travellers from wuhan euro surveillance : bulletin europeen sur les maladies transmissibles preliminary estimation of the basic reproduction number of novel coronavirus ( -ncov) in china, from to : a data-driven analysis in the early phase of the outbreak an updated estimation of 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assessing the impact of reduced travel on exportation dynamics of novel coronavirus infection ( covid- ) the effect of human mobility and control measures on the covid- epidemic in china the time scale of asymptomatic transmission affects estimates of epidemic potential in the covid- outbreak a general purpose sampling algorithm for continuous distributions (the t -walk) monte carlo statistical methods statistical and computational inverse problems jxvh would like to acknowledge support from grant papiit-unam in and support from the department of mathematics of the university of miami. jxvh also thank prof. steve cantrell and prof. chris costner for their support. we also thank dr. david baca carrasco for his help in the earlier reference search. key: cord- -qeuvymu authors: banai, reza title: pandemic and the planning of resilient cities and regions date: - - journal: cities doi: . /j.cities. . sha: doc_id: cord_uid: qeuvymu the emergence of the coronavirus pandemic motivated this paper, which revisits the nexus of public health and the city, itself a main source of a pandemic which similarly threatens the lives and properties of the world population gradually one glacier at a time: climate change. we argue that pandemics expose both the vulnerability and resilience of the urban system expansively, from rooftop to the region, but also serve as change agents for the planning of resilient cities and regions globally. the discussion of the urban system and the pandemic is comparative, with the recent coronavirus and climate change, a persistent, long-lasting pandemic. the historical and critical review and synthesis of the durable concepts of the urban system at the kernel of the theories and practices of urbanism is highlighted by place matters, cyberspace, density, access, and the city-region. we note the implications for reconfiguring the resilient urban system of the future effectively with pandemic as change agent and the comprehensive plan and its regulatory zoning ordinance as implementation tool. public health and city planning have common disciplinary purposes. city planning's professional identity is defined as a guardian of "public interest." standard city planning enabling act (scpea, u.s. department of commerce ) is even more specific, defining municipal planning's promotion of "health, safety, and general welfare" of the population. public health is about identification, control, and prevention of disease. the common references to parks and open spaces with a physiological metaphor-the "lungs" of the city-connotes the nexus of public health and the city explicitly. city planning's focus is the physical layout of the city in a manner that promotes health and prevents the occurrence of diseases in the first place. concomitantly, city and regional planning and design theories, concepts, regulations, and practices emerge historically in response to public health crises, including pandemics, pollution with rapid industrialization, congestion with urbanization, and loss of green space in cities. the origin of modern city planning is aligned with sanitary, housing, and social reforms since the mid-nineteenth century and around the turn of the twentieth century-movements dealing with inadequate sanitation-itself a pandemic response-and limited access to air and sunlight in crowded tenement housing and dilapidated slums. the coronavirus pandemic has at least temporarily significantly reconfigured city life-the relation of work and residence, and leisure, use of public space, safety and security of transportation, both public and private-and posed fundamental equity of access to resources. a smart planning scenario could not have anticipated and illustrated the wide-ranging, impactful socio-spatial dimensions of the coronavirus pandemic in entirety this vividly, let alone applied standard urban planning tools-the comprehensive plan and zoning regulations-proactively (banai, a; kelly, ) . it turns out, planning's tool set are disproportionately limited piecemeal or disjointed compared to the magnitude and wide-ranging scope of the better known, durable pandemic of climate change. however, the global experience of the coronavirus pandemic also informs and suggests what kind of planning is commensurate with the dimensions of the challenges posed by climate change. it turns out, pandemics expose the vulnerability and resilience of the urban system, ironically with durable concepts of urbanism, highlighted from the rooftop to the region. the paper is organized by a discussion of durable concepts of urbanism, with implications for reconfiguring the urban system, aided by invoking urban planning's standard tool-the comprehensive plan. the paper concludes with a discussion of planning resilient urban form of the future in the era of climate change. oxford dictionary defines pandemic with its greek origin in midseventeenth century, pandēmos, all (pan) people (demos) "prevalent over a whole country or the world." arguably, climate change, which is prevalent globally, fits that definition, just as coronavirus does. a question is immediately raised: which pandemic is more costly-coronavirus or climate change? hint: one pandemic is a one-hundred-year event, compared to the other, with an incubation period that started with the industrial revolution in s. however, the two pandemics have a similar pattern of spread: exponential. measured by loss of human life, unemployment, underemployment, social isolation, public expenditures, reduction in gross domestic product, and supply-chain interruption, the costs of coronavirus are immense. however, compare the cost of climate change. green house gas (ghg) traps pollutants in cities. combine tailpipe and smokestack pollution from vehicles, buildings, factories, and heat islands in cities, and there is recipe for respiratory illness, including asthma and cardiovascular disease, consequential for the children, the elderly, and populations predisposed with genetic chronic health conditions. parenthetically, people with respiratory and cardiovascular illness and diabetics, which are also linked to urban form-induced obesity as well as poor diet, have a lower chance of surviving the other pandemic: coronavirus. furthermore, consider the costs of entire islands inundated due to sea-level rise, or so-called king (or high) tides that infiltrate coastal cities' groundwater table with sea salt, threatening drinking water or causing frequent surficial flooding depositing sewage into rivers and lakes (chicago), and disrupting traffic in city streets (miami). add the mitigation costs of levee, dike, and sea-wall construction in coastal cities globally, like new york city, new orleans, amsterdam, venice, and london. include droughts that threaten agriculture, causing food insecurity that subsequently threatens employment and national security (even a source of failing states), and induces population migration in search of survival. this is not an exhaustive itemized costs brought about by the silent pandemic of climate change gradually taking its toll on the built and natural environments. the evidence of climate change pandemic and its consequences for cities and regions is compelling. the itemized list in the comparison of pandemics of climate change vs. coronavirus is tentative with respect to consequences of coronavirus. the juxtaposition of the two pandemics, however, is instructive. ironically, one pandemic has a positive impact on the other (see fig. ). images in the media show clearer skylines and iconic, ground-level landmarks, such as the eiffel tower, to be more visible than usual due to quarantines in otherwise congested, polluted, populated, heated-up cities. there are even the images of venice's canals and waterways looking clearer than ever, as the coronavirus quarantine leaves them undisturbed. u.s. environmental legislation has ensured public health of the city with clean air and clean water for the past half-century, abating ghgs-carbon dioxide, sulfur dioxide, nitrate dioxide. similarly, clean water legislation regulated the disposal of cities' waste into rivers, the sources of drinking water and aquatic life. ohio's cuyahoga river was once so polluted that it caught fire, but owing to the clean water act, it's now home to marine life. however, the images of clean waterways and clear skylines during the coronavirus epidemic suggests next steps toward further management of waterways and air pollution in cities. we hope for a vaccine that will cure the coronavirus, but no such thing can solve the pandemic of climate change. it takes more than a shot in the arm. surreal images of cities known for their population density, air pollution, and traffic during the pandemic appeared in the media-skyline visibility but with empty streets, deserted downtowns, blighted parking lots surrounding commercial retail stores, empty office buildings, locked college and university gates, and desolate public parks. in the pre-coronavirus era, empty stores and parking lots and desolate public spaces were regarded as indicators of intolerable blight, justification for urban revitalization. ironically, among the vestiges of blight and sprawl is the drive-in movie theatre, revived because of the pandemic as a safer alternative than the big-box movie theatre. and the impact of social isolation on mental health is also recognized. how could cities and regions sustain the public health benefits of cleaner air and water with a resilient urban form and a smaller ecological footprint post-coronavirus? the coronavirus pandemic, despite its devastatingly inimical tolls on humans, sheds light on the architecture of urbanism, revealing strengths and vulnerabilities of the urban system. the pandemic has in effect enabled a social experiment with controls that are usually possible only in the closed system of a laboratory, not in the open system of a society; however, this experiment calls for a rethinking the urban system with expansive concepts of resilience in planning cities and regions. we note the implications for the comprehensive plan in the face of climate change. the literature on the importance of place, and the related discussion of place-making in urban studies abound. much of the discourse of the new urbanism which emerged in the s is about civic places, which disappeared in the private, subdivided spaces of suburbia (katz, ) . the american dream of a house, a yard, and car excluded community, as hayden ( ) argued (see also calthorpe, ; mcharg, mcharg, / . the mainly residential suburbs bereft of civic spaces could not accommodate a social place for the teenage population without the car, with the exception of vacant lots and buildings under construction. suburbia segregated commercial-residential-public land use, in contradistinction to the historic american main street with fine-grained, mixed land use, and an accessible park. the comprehensive (master) design plans of new urbanism aimed to remedy this shortcoming with integrated land use and pedestrian-friendly access, with enhanced public realm elements, which occupy prominent landmark locations with water feature and articulated surficial materials of the sidewalks anchored by gazebos and pocket parks, heeding the pedestrian as well as vehicular circulation. when the pandemic limited or prohibited access to the public realm, its significance became even more apparent, albeit with an eerie sense of a public realm that is no longer a public domain. the longing for the city's public realm, temporarily off-limits during the pandemic, was expressed through the building balcony, which architecturally transitions between public and private space. the balcony substituted for an inaccessible public realm-from the street, the town square, the park, the waterfront, the cemetery, to places for religious gatherings, church, synagogue, mosque-places that functioned, albeit with some adaptation, aided in cyberspace, and occasionally in defiance of any imposition of control (see also oldenburg's ( oldenburg's ( / ) notion of the necessity of "the third place" where essential human interaction occurs beyond work and home; see also calthorpe & fulton's, , page elaboration). the limit of the experience of physical place via cyberspace is readily revealed if reminded by lynch's ( ) cognitive mapping of the five elements that makes the city legible or imageable, and the sense of place attributes including ambience, sound, smell, topography (steepness of roads) and the like. if eclipsed in dense theoretical academic writing, commercial and social media alike exemplified the significance, actual experience of and the longing for the city's public realm, particularly during a pandemic. the vitality of the city is determined by place. where else? vitality is among the five "performance dimensions" of good city form, defined by lynch ( , page ) as "… the degree to which the form of the settlement supports the vital functions, the biological requirements and capabilities of human beings-above all, how it protects the survival of the species." (see also banai & rapino, .) where better to observe the function (or dysfunction) of the settlement form but in the city's public realm, particularly in a pandemic. it is not just the pandemic of an infectious disease that is consequential for the vitality of the city's public realm. climate change's extreme weather pattern with heavy rain events threatens city's vital public realm element with street flooding. the point-and non-pointsource pollution during intense rain events threatens city's water bodies. the comprehensive plan can increase cities' resilience by rezoning blighted, abandoned industrial and commercial properties as green open space buffers that absorb or slow surficial runoff that creates hot spots of pollutants in cities' rivers, creeks, and streams. a dominant element of the public realm is the suburban arterial street. the wide arterial street is enhanced if "shared" equitably accommodating movement of pedestrians and vehicles. the long-term comprehensive plan is a tool to accomplish this aim, by physical design alterations that "calm" traffic and thereby increase public safety. integration of green space in the arterial street in the form of medians or embankments enhances pedestrian safety while abating runoff during the intense rain events that characterize climate change. telecommunications technology and cyberspace substitutes for risky in-person communication in physical space during an easily transmittable pandemic. communication theorists widely touted the benefits of interaction at a distance even pre-coronavirus. among others, webber ( ) argued the case for "community without propinquity." the coronavirus effectively revived and reminded us of the merits of the arguments for and against more widespread online communication. arguments in favor of communities of place rather than communities of interest in cyberspace (calthorpe & fulton, ) , however, suggest plausibility with the experience of communication during pandemic and the longing for interaction in physical space of place and neighborhood, and the (physical) public realm, even in defiance of state control. economic and urban theorists up the ante by privileging the benefits of interaction with economies of agglomeration in physical space necessary for efficient business transaction (see also lynch ) . notwithstanding the facility of communication in cyberspace, still an urban form of the future-the aerotropolis-is defined by a physical space that accommodates agglomeration of firms and business transactions in a central location akin to the city's central business district (cbd) (kasarda, , kasarda, , kasarda and lindsay . the pandemic showed us the inequity of access due to lack of broadband technology-the digital divide-so the comprehensive plan is an ideal tool for enhancing city's resilience by a planning infrastructure that not only includes water, sewer, and roads, but also broadband service (see also kelly, ) . we learned from the pandemic how vital functions are interrupted-education, from pre-school to college; health care; and access to jobs and services. broadband access is not a luxury but a necessity when in-person access is interrupted or not an option. parenthetically, a similar logic holds in planning transit-supportive or transit-oriented developments. the urban form, with its land-use mix and proximity to the centrally located retail and office services are desirable features because of walkability, regardless of the availability of transit (calthorpe, ; calthorpe & fulton, ). the environment-behavior nexus was investigated more than half a century ago by the then-burgeoning subfield of environmental psychology. these well-known laboratory experiments revealed how rats develop abnormal behavior when subjected to crowding. concomitantly, the classic environmental-behavior studies informed how urban form likely impacts the physical and mental health of the urbanists. even obesity (body-mass index) is linked to urban form (walkability), elucidated in the contrast of compact vs. urban sprawl (e.g., frumkin et al., ; ewing et al., ) . commentators, backed by empirical evidence, touted the public health benefits of cities that promoted walkability with multi-modal regional mobility, thereby abating obesity, and which contained places of work as well as residence and leisure, thereby minimizing stressful commuting to work. (ewing et al., ; frumkin et al., ) . the urban-studies literature has given considerable attention to density. density figures prominently in urban studies since the feasibility of a vital element of urban form-public transit-is contingent on population density's minimum threshold. however, even predating the laboratory experiments of the environmental psychologists, an english thinker (howard, (howard, / around the turn of the century proposed and later constructed a garden city that meant to address the health, safety, and general welfare of industrial city residents exposed to all the negative consequences of industrialization, crowding, congestion, pollution, sprawl, and lack of parks and open green space. arguably, the small, low-density garden city land use in balance with the natural environment is a more resilient model of urbanism than the compact, high-density new york city in the face of epidemic guidelines that call for social distancing and low population density of the public realm. durable concepts of urbanism originate prominently in the contrast of two prominent thinkers, one english and the other french. the french modernist architect-urbanist le corbusier ( corbusier ( / ) touted his tower-in-the-park skyscraper concept of contemporary city as a better solution to the rapid urbanization of population and congestion spurred by industrialization. the contemporary city accommodated times the population of the garden city with only , that his english predecessor, howard ( howard ( / had proposed in skyscrapers (legates & stout, ) . the "popular response" to plan voisin, a later version of the contemporary city proposed for central paris in , was "outrage" (legates & stout, ; see also birch, ). however, corbusier's concept of a dense, modern urbanism with the iconic skyscraper endures globally in cities, famously in the iconic new york city (see lang, ) . the pandemic cast a negative image of urban density, and its corollary, public transportation, as hotspots of the coronavirus (new yok city, los angeles, and compact spanish, italian, and english cities). density figures prominently in contemporary accounts of new urbanism since density correlates with walkablity in the "transit metropolis" (cervero, ) . even before the coronavirus pandemic, the dense high-rise buildings-particularly for public housing in neighborhoods disconnected from the rest of the city-connoted the image of the vulnerability of their impoverished, isolated, low-income residents. the destruction of st louis's pruitt igoe-designed by a renown modernist architect-demonstrated the unsustainability of the high-rise public housing project. in contrast, modern high-rise buildings could densely accommodate residents in resort towns with a premium view and rent. their residents could weather the lock-down, shelter in place guidelines during the pandemic. however, public housing, following federal guidelines like hope vi and choice neighborhood, is now lowrise with a front porch that resembles houses in older american city neighborhoods before the suburbanization of businesses and population spurred by post-war national interstate highway system. however, density is still a hard sell in popular discussions of realestate markets. low-density single family rather than multi-family housing is politically palatable to politicians who count votes with rooftops, even though compact land development is arguably environmentally more sustainable particularly in the face of climate change and demographic shift (immigration) that increase demand for housing and ancillary urban services-water, sewer, and road. in urban-studies literature, discussions of density and how higher thresholds are tolerated, particularly by urbanites accustomed to low-density suburban sprawl, extend to the justification of trade-offs, i.e. how density is plausibly compensated with other factors, (urban) design features that enhance aesthetics of place, and (land-use) diversity that improve proximity of housing to jobs, services, and amenities like parks and open space-so-called ds (for impact on travel, see cervero & kockelman, ) . density correlates with demography. in the context of the pandemic, still other factors must be added to the ds in deference to public health: demography, disaggregated by racial composition, ethnicity, age, and income. the correlations among the factors are instructive. at risk are residents characterized by compact living and commuting, transit-dependent population, or workplace-residence separation exacerbated by the digital divide. for the purposes of public health during the epidemic, the aforementioned factors require optimization simultaneously. the comprehensive city plan is a logical tool for that optimization. let us posit the concept of access inclusively with lynch ( ) as a dimension of the performance of urban form, not merely by modes of travel to work or services, but also availability of resources. perlman and o'meara ( ) remind us that the urban poor are likely located in "ecologically fragile areas of cities," without adequate water and sewers. coronavirus-prevention guidelines include frequent handwashing. how could these hygiene standards be met when there is no access to running water in poor settlements of the global north and south? the navajo settlement is but one example in the u.s. (see also www.digdeep.org). war-stricken regions of the world whose populations are victimized by global power play, such as libya, yemen, syria, turkey, and afghanistan, and refugees in greek islands, are among other examples. once again, pandemics-be they climate change or the coronavirus-reveal the vulnerability of the population in urban, periurban, and rural areas with global inequity of access to the resources fundamental to human survival. the coronavirus pandemic had a positive effect too, with the u.n. directorate's declaration to halt ongoing wars globally, particularly in the middle eastern countries most heavily impacted. the impact of military conflicts on the global population and environment is rarely discussed in the literature of climate change. the advocacy planning argument of the s and s that posed the limit of comprehensive master plans and stressed the necessity of the "plural plan" responsive to the underrepresented, marginalized, disenfranchised, colonized population revives the discussions of the equity of access to resources with environmental justice in the twenty-first century, particularly in the face of pandemics (see davidoff, ) . the wealth of nations is created in cities, jacobs ( ) reminds us. global environmental sustainability starts with urban environmental sustainability (perlman & sheehan, ) . cities provide economies of agglomeration, and of scale with efficiencies of resource utilization. however, the idea of abating pressure on resources concentrated in urban centers, like london and new york, and striking a balance of nature and development by spreading population to the larger region did not stop in england with howard's concept of the garden city, noted above. the garden city idea influenced a group of regionalists, or de-centralists with english connections in new york. a multidisciplinary team, journalist (howard) , socio-cultural critic (mumford), social reformer (bauer), economist (chase), biologist (geddes), sociologist (perry), forester-naturalist (mackaye), a developer (bing), and several architects (ackerman, whitaker, wright and stein) formed the regional plan association of america (rpaa, s; see also banai, banai, , b ). an exemplary feature of this regional planning is its multi-scale scope: from neighborhood to the region. it turns out, the "neighborhood unit" (perry, ) is an enduring concept manifested in new urbanism that emerged in s. cities ( ) the economist member of the regional plan association of america (rpaa s), stuart chase, considered the bigger picture of the efficiency of the urban and regional economy as a problem, stated thus: "the regional planning of communities would wipe out uneconomical national marketing, wipe out city congestion and terminal wastes, balance the power load, take the bulk of coal off the railroads, eliminate the duplication of milk and other deliveries, short circuit such uneconomic practices as hauling pacific apples to new york customers by encouraging local orchards, develop local forest areas and check the haulage of western timber to eastern mills, locate mills near cotton fields, shoe factories near hide producing areas, steel mills within striking distance of ore beds, food manufacturing plants in small giant power units, near farming belts." (quoted in hall, , pp. - ) for further discussions of local vs. global, economic vs. ecologic tensions in urban development, see korten's ( ) political-economic critique of capital markets, deemed as exacerbating ecological systems, shuman's ( ) "replacing imports" in self-reliant local communities in a global age, and roseland and soots' ( ) "strengthening local economies." the break in the global supply chain during the coronavirus pandemic made the dire consequences abundantly clear, particularly for the health-care sector with loss of life. how "uneconomical," chase might ask, is the practice of offshoring industrial and manufacturing production and sending the finished products, in whole or part, back to the country of origin by air, sea, river, rail, and road? parenthetically, airline tickets now relay magnitude of carbon footprint in trans-atlantic passenger flights. for a sustainability assessment of a futuristic concept of urban form anchored by a "globally networked economy's airport"-the aerotropolis-see banai ( ) . air transportation's contribution to global climate change remains awaiting the development of technologies that economically sequester atmospheric carbon. the idea of the city and the region as a unit is at the kernel of how the u.s. census defines the metropolitan region, metropolitan statistical area (msa) determined by commuting (see banai & wakolbinger, ) . parenthetically, this very commuting among inner city and suburban municipalities aids in the transmission of coronavirus, from high-density urban to low-density rural counties. young ( ) quotes the governor of new york, "many people in the new york city metro area live and work across three states' borders, so just as they coordinated shutting down various businesses [during coronavirus], it makes sense to eventually together bring people back." the holistic concept of the metropolitan region that highlights the functional links among urban and regional economies also reveals the strengths and limits of the urban system, and thereby informs the comprehensive city plan's objectives of enhancing sustainability and resilience of the built and natural environments of climate change. human activity's gradual degradation of the natural environment has a long history that has only intensified since the onset of the industrial revolution, with exponential growth in carbon emission due to burning of fossil fuel-coal, oil and natural gas-sources of ghs. a poplar idiom is aptly invoked. the planet earth's holding capacity, like the proverbial camel, is finite, continually burdened with harmful human activity, diminishing gradually by each melting glacier, like straw on a camel's back. (formally, economists use the term "margin," or "last unit" to explain concepts, as in the cost of producing one more unit of a product, the marginal cost of production.) the precise tipping point, or better stated, breaking point for the planet earth beyond any recovery, is in debate. the signs are visible in the built and natural environments, with droughts, fires, floods threatening food security, national security, employment security, rising poverty, inequality, and global diaspora (brown, (brown, , . wackernagel and rees ( ) measure ecological footprint by amount of land needed to sustain human needs for production of food and disposal of waste. land is a finite resource. by that definition, wackernagel and rees ( ) illustrate that if everyone lived like people in the netherlands, then two additional planet earths would be needed. parenthetically, the netherlands example is ironic, given the compact dutch urban form integrated with nature and exemplary sustainability practices (see beatley ) . furthermore, amsterdam's schiphol airport is regarded as a model for the "aerotropolis," a futuristic concept of urban form (kasarda and lindsay ) . there is no literature on the public heath aspects of the aerotropolis; however, comparing it to the exemplary amsterdam metropolitan region that contains the airport (schiphol) offers some clues. the region is characterized by the historic structures, integrated urban development and nature, compact, mixed-land use with multi-modal regional mobility architype of european cities (see beatley, ). european countries with net zero are the ideal of how we should live next. however, pacala and socolow ( ) offer a variety of existing technological solutions that limit carbon emission over the next fifty years(see also calthorpe, ) . the limit is achieved by a combination of alternative sources, from renewable energy (solar, wind, hydro) to conservation to nuclear power. interestingly, in spain, a country hit hard by one pandemic (coronavirus), the road to recovery is through solutions to the other pandemic-climate change-such as pledging to outlaw fossil fuel-coal, oil, natural gas-toward % renewable sources of energy. the pandemic has a global reach, by definition. the method of the approach and presentation of this paper is comparative by juxtaposing the pandemics of climate change and coronavirus, and through a historical and critical review and synthesis of the durable concepts of the urban system at the kernel of the theories and practices of urbanism expansively, from rooftop to the region, highlighted by place matters, cyberspace, density, access, and the city-region. the urban system connotes a holistic approach, with a synthesis of concepts of the urban system elements that are heretofore regarded individually particularly in dealing with resilience. the holistic notion of the urban system thus sheds new light on the resilience of system parts when regarded as a whole. we have juxtaposed the recent coronavirus pandemic with climate change, a persistent, long-lasting pandemic which threatens civilization, not merely urbanization (brown, (brown, , . pandemics expose the vulnerability and resilience of the urban system ironically with durable concepts of urbanism, from rooftop to the region. the recent pandemic has posed the dilemma of physical vs. virtual space. the accounts of this distinction appear with durable concepts of place and space in urban studies, which shed light on recent pandemic-related discussion. cyberspace and physical space are related concepts. the distinction made between "community of place" vs. "community of interest" is revisited in urban studies, particularly with the concepts of placemaking. there are limits and possibilities in both cyberspace and physical spaces. the critical role of access is also posed in both spaces, with respect to efficiency and justice. one space asserts the dilemma of a "digital divide," whereas the other asserts the dilemma of public vs. private transportation with equity and efficiency. place density is also a durable, controversially held concept of urbanism. we have highlighted discussion of density dating from first decades of the twentieth century, relating to the challenges of public health. the recent pandemic posed anew the challenge of public health with urban density. pandemics, while exposing the vulnerabilities of the urban system, are also a driver of positive change in planning resilient urban form of the future. reconfiguring the urban system in the era of climate change is compelling with the majority of world population living in cities and regions. at the outset of the paper (pages - ), we pose the kind of planning that is commensurate with the dimensions of the challenges posed by the pandemic needed for resilient cities. we argue the case for comprehensive planning, and provide specific interventions toward resilience, with place matters, cyberspace, density, access, and the cityregion. the logic of the long-term comprehensive plan is compelling given the interrelated elements of the urban system. the argument is that resilience of the whole is dependent upon the resilience of the individual parts. the paper thus provides specific areas of how the parts are addressed with elements of the urban general or comprehensive plan. for brevity , the discussion of the application of comprehensive planning as a mode to enhance resilient cities is limited. the comprehensive plan with a legal backing is long-term oriented, with parts that account for key physical elements that prepare the urban and regional system to confront the challenges of climate change. the comprehensive plans rarely include physical elements that enhance the urban and regional resilience proactively in the face of climate change. we have identified how the urban system is reconfigured, from the infrastructure of the public realm (the street, town square, park, and open space) to place density with a human-scale, telecommunication, regarded at par with essential infrastructure of water, sewer, and road, to integrated urban and regional economies that enhance efficient, sustainable local production and distribution of resources. further studies fruitfully build on our comparative, evaluative framework of pandemics as drivers of change toward resilient cities of the future. social theory and the region: from the regional planning association of america to the restructuring of socio-spatial theory, with policy implications plan vs project dilemma in urban and regional studies revisited: a progress review of urban and regional studies the metropolitan region: from concepts to indicators of urban sustainability the aerotropolis: urban sustainability perspectives from the regional city urban theory since a theory of good city form ( ): a progress review a measure of regional influence with the analytic network process planning for sustainability in european cities: a review of practices 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personal relationships that could have appeared to influence the work reported in this paper. key: cord- -qfvm x authors: maponga, brian a; chirundu, daniel; gombe, notion t; tshimanga, mufuta; shambira, gerald; takundwa, lucia title: risk factors for contracting watery diarrhoea in kadoma city, zimbabwe, : a case control study date: - - journal: bmc infect dis doi: . / - - - sha: doc_id: cord_uid: qfvm x background: kadoma city experienced an increase in watery diarrhoea from cases during week beginning (th) september, to cases during week beginning (th) september . the weekly diarrhoea cases crossed the threshold action line during week beginning (th) september at the children’s clinic in rimuka township, and the remaining four clinics reported cases crossing threshold action lines between week beginning (th) september and week beginning (th) september. eighty-two percent of the cases were children less than years old. we conducted a case controlstudy to determine risk factorsfor contracting watery diarrhoea in children less than years in kadoma city. methods: an unmatched : case control study was conducted in ngezi and rimuka townships in kadoma city, zimbabwe. a case was a child less than years old, who developed acute watery diarrhoea between (th) september and (st) october . a control was a child less than years old who stayed in the same township and did not suffer from diarrhoea. a structured questionnaire was administered to caregivers of cases and controls.laboratory water quality tests and stool test results were reviewed.epi info™ statistical software was used to analyse data. results: a total of cases and controls were enrolled. independent protective factors were: having been exclusively breastfed for six months [aor = . ; % ci ( . - . )]; using municipal water [aor = . ; % ci ( . - . )]; using aqua tablets, [aor = . ; % ci ( . – . )] and; storing water in closed containers, [aor = . ; % ci ( . – . . ). the only independent risk factor for contracting watery diarrhoea was hand washing in a single bowl, [aor = . ; % ci ( . – . )]. salmonella, shigella, rotavirus, and enteropathogenic escherichia coli were isolated in the stool specimens. none of the municipal water samples tested showed contamination with escherichia coli, whilst of ( %) shallow well water samples and of ( %) borehole water samples tested were positive for escherichia coli. conclusions: the outbreak resulted from inadequate clean water and use of contaminated water. evidence from this study was used to guide public health response to the outbreak. acute diarrhoea is defined as the passage of three or more loose or liquid stools per day, in a period not exceeding days. other types of diarrhoea include dysentery; and persistent diarrhoea which lasts days or longer. patients presenting with diarrhoea can also present with other symptoms such as vomiting, fever, and body weakness. diarrhoea causes loss of body fluid and electrolytes, which can result in dehydration. if dehydration is not corrected, death can result [ ] . the causes of diarrhoea can be bacterial, viral or parasitic. bacteria causes of diarrhoea include vibrio cholerae, escherichia coli, campylobacter jejuni, salmonellae and shigella species. viral causes of diarrhoea include rotavirus, adenovirus, and corona viruses. parasitic causes of diarrhoea include giardia, entamoeba, cryptosporidium and the helminthes (strongyloides, schistosoma) [ ] . diarrheal disease is a leading cause of child mortality and morbidity in the world, and mostly results from contaminated food and water sources.in developing countries, children below years experience on average episodes of diarrhoea every year. globally, there are about billion cases of diarrhoeal disease every year [ ] . fifteen percent of child deaths are directly attributable to diarrhoeal diseases [ ] . according to the world health organization (who), key measures to prevent diarrhoea include access to safe drinking-water, improved sanitation, exclusive breastfeeding for the first six months of life, good personal and food hygiene and health education about how infections are spread [ ] . in , kadoma city had an estimated , inhabitants. of these , were children less than years old based on the census projections [ ] . more than half the population resides in the city's rimuka township. nearly the whole population in kadoma city has access to piped water. however, demand for water is very high, reaching as high as mega litres per day, yet the city can only pump at best mega litres per day [ ] . the quantity of water pumped is further compromised by recurrent power cuts to the water treatment plants. in the absence of municipal water, residents use shallow wells and boreholes among others as water sources [ ] . kadoma city has had recurrent problems with watery diarrhoeal outbreaks since . in , a rotavirus outbreak killed children [ ] . a cholera outbreak in and affected , people, with deaths [ ] . another cholera outbreak in affected people and caused deaths [ ] . most of the problems, such as shortage of water, and recurrent sewer blockages have not had permanent solution due to lack of financial resources. in , kadoma city experienced an upsurge of watery diarrhoeal cases during week (week beginning th september), in ( figure ). the total cases reported by the city's five clinics doubled from to cases between week and . the cases further doubled from to between week and week . the weekly watery diarrhoeal cases at the under clinic crossed the action threshold line during week ( figure ). the action threshold was defined using the c cusum method (defined as the sum of the mean plus three standard deviations for preceding weekly diarrhea recordings, skipping two most recent weeks) [ ] . the diarrhoeal cases at the children's clinic increased fold, from to cases, between weeks and . the remaining four clinics (for all age groups) also experienced more than doubling of cases between week and week . initial analysis showed that about % of the cases were children less than five years old. the study was conducted to determine factors associated with contracting watery diarrhoea in children less than five years old. an unmatched : case-control study was conducted in kadoma city's rimuka and ngezi townships. the study was conducted among children less than years old. a case was defined as a child less than five years old who presented to a health facility with acute watery diarrhoea, with or without vomiting and other symptoms, between th september and st october , who had been resident in kadoma city for one week prior to onset of symptoms. a control was defined asa child less than five years old, who did not develop diarrhoeabetween th september and st october , and had been resident in kadoma city, one week prior to the interview. children whose caregivers agreed to participate were recruited into the study. children who had passed diarrhoea for more than days were excluded from participating in the study. epi info™ statistical software was used to calculate sample size. assuming % exposure in controls and % exposure in cases, using unchlorinated water, odds ratio of . [ ] , % confidence level, % power, and % refusal rate, we calculated a minimum sample size of ( cases and controls). multistage sampling of cases was done. rimuka and ngezi townships were selected because they were the most affected. using proportionate sampling, rimuka was to provide ( %) cases whilst ngezi was to provide ( %) cases. cases were selected from clinic line lists; using random numbers generated using microsoft™ excel . a control was selected from a household houses away from a case. where there was more than one child less than years old at the household, a child whose age was closest to the age of the case was selected. if there was no child less than years old, or if the caregiver declined to participate, the next house was selected till a less than years old was obtained. a pre-tested, interviewer administered questionnaire, was used to collect data from caregivers of cases and controls. the information collected included caregiver and case/control demographic information, symptoms, knowledge of caregiver on diarrhoea illness and treatment, duration of exclusive breast feeding, immunization status, the source of water, water treatment and storage, and sanitation facilities at the family home. the questions were in english and local shona languages. record review of water surveillance reports was done. the water quality parameters tested were bacteriological and chemical (chlorine content for municipal water, and ph). bacteriological water quality tests had been done using a delagua field testing machine. water samples that were found with zero colonies after incubation for hours were considered satisfactory. residual chlorine content was tested using the lovibond comparator using dpd tablets (n,n diethyl- . phenylenediamine sulphate) to check colour changes. specimens within the range . to . parts per million (ppm) were considered satisfactory. the ph was measured with the same equipment using phenol red tablets. specimens with ph ranging between . and . were considered satisfactory. the results were reported as proportions. data were analyzed using epi info™. means, proportions, frequencies, odds ratios and chi square tests at % significant levels were generated using the software. stratified analysis and forward step-wise logistic regression analysis was used to control for confounding and effect modification. permission to conduct the study was obtained from the local health authorities. ethical review was done at the health studies office, university of zimbabwe. written informed consent was obtained from all study participants caregivers. children or relative with diarrhoea found during interviews were referred to the nearest health facility for free treatment. a total of , cases of watery diarrhoea were attended to between th september and nd november . of these, ( %) were residents of kadoma city. the crude attack rate was per , people. five hundred and fifty two cases ( %) were females. six hundred and ninety three ( %) cases were children less than years old. the attack rate among children less than years old was per , people, whilst for those above years old, the attack rate was per , people. five cases, all children less than five years old died of diarrhoea. the crude case fatality rate was . %. one child died in hospital, and four children died at home after having sought treatment at health facilities. all the residential areas in kadoma city were affected. the highest risk of developing diarrhoea was in ngezi township, with an attack rate of per , people, followed by rimuka township, with an attack rate of per , people. however, during the early part of the outbreak, the highest risk of contracting diarrhoea was in rimuka township. figure shows the epidemic curve for kadoma city for the period st september to rd november . the outbreak commenced during the week beginning th september. the epidemic curve shows multiple waves with progressively taller peaks that are - days apart up to the st of october. the peaks became progressively shorter, until less than cases were attended to per day from rd october . a total of stool specimens were submitted to the local laboratory. thirty specimens yielded e.coli, yielded shigella species, yielded salmonella species and one yielded rotavirus. one out of the sixteen specimens submitted to the national virology reference laboratory tested positive for rotavirus. two of the specimens/isolates submitted to the national microbiology reference laboratory (nmrl) were confirmed as enteropathogenic escherichia coli. no cholera or cryptosporidium was isolated. all municipal water samples tested were below the threshold limit for contamination with escherichia coli. three of the ( %) borehole water samples and of the ( %) shallow well samples were above the threshold for contamination with escherichia coli. thirty-two ( %) of the municipal water samples tested for chlorine had chlorine levels within normal range. all the samples had ph levels within normal range. the samples were collected and analyzed between st september and nd october . a total of cases and controls were recruited into the study. there were no significant differences in the demographic characteristics of cases and controls as shown in table . less than % of cases and controls caregivers had received health education on diarrhoea six months prior to the outbreak. the knowledge on prevention and home treatment of diarrhoea was fair, and did not differ significantly between cases and controls as shown in table . table . statistically significant protective factors against contracting diarrhoea were: using municipal water source table . hand washing in a single bowl [aor = . , % ci ( . - . )] was an independent risk factor for contracting diarrhoea. independent protective factors against contracting diarrhoea were: using municipal water [aor = . , % ci ( . table . this study sought to establish risk factors for contracting watery diarrhoea among children less than five years old in kadoma city. the epidemic curve is typical of a propagated outbreak, highly suggestive of person-toperson transmission. the multiple peaks, to days apart, suggest the incubation period of the causative organisms to be between to days. the causative organisms that were isolated, (rotavirus, salmonella, shigella and escherichia coli) fit into the average incubation period of to days which is typical of faecal contamination [ ] . the importance of hand washing practices in preventing diarrheal illness is highlighted in this study. hand washing in a single bowl was found to be a risk factor for contracting watery diarrhoea. it is biologically plausible for infection to be spread from one person into the water, then to the next person. having a hand washing facility at home was found to be protective as the facility encourages run to waste method of hand washing, especially after using the toilet. these findings are supported by several studies. a systematic review of several studies, estimated that appropriate hand washing with soap, could reduce the risks of severe intestinal infections and of shigellosis by up to % and %, respectively [ ] . the water could have been contaminated by blocked sewer. the problem of blocked sewer had earlier been highlighted by mangizvo r.v et al., [ ] . this could explain the contamination of shallow wells and boreholes in kadoma city, most probably through seepage. in karachi, pakistan, khan et al. demonstrated that % of sewer influent samples were positive for rotavirus, which was also identified in one of the cases in the outbreak in kadoma city [ ] . contamination of water can occur at any stage from the source, to the point of use. the biological plausibility of storing water in a closed container, boiling and use of aqua tablets was demonstrated in this study. the use of chlorine containing materials have been made use of in situations of acute water shortage, where people tend to use unsafe sources of water, as reported by lantagne d s, et al., in [ ] . in kadoma city, in this epidemic, the use of municipal water was protective, compared to water from other sources (aor = . , p = . ). similar findings were obtained in harare by gonese g, et al., in . (risk factors associated with salmonella outbreak in budiriro suburb, harare city, zimbabwe, -unpublished). the laboratory tests on municipal water which was of satisfactory bacteriological and residual chlorine levels support the findings. at the same time, families who accessed water from municipal supply are more likely to access water in the family home. this study demonstrated that distance of the water source from home increased risk of developing diarrhoea. this results in families accessing less than the required amount of water per day, compromising personal hygiene practices such as hand washing. exclusive breast feeding for months was protective against developing diarrhoea. exclusively breastfed children were protected as they were unlikely to take any other foods or fluids likely to be contaminated. this protective effect was less for children on mixed breastfeeding and weaned from their mother's milk.the protective effect of exclusive breastfeeding had been demonstrated using different study designs, in different settings. in belarus, kramer m.s. et al., , reported that exclusive breast feeding reduced risk of diarrhoea by % [ ] . in guinea bissau, mølbalk k, et al., , reported that partial breast feeding, rr = . ( . - . ), and no breast feeding rr = . ( . - . ) increased risk of diarrhoea [ ] . in zimbabwe, a nutritional survey in reported that . % of children were [ ] . thus, efforts to increase the prevalence of exclusive breast feeding could reduce the impact of diarrhoea on child morbidity and mortality, in zimbabwe. limitations of this study included the following: controls might have contracted the disease but not developed clinical symptoms leading to case ascertainment bias. this could have under estimated the strength of some associations. the observed protective effect of the water treatment tablets is self reported, thus may lead to bias. some of the caregivers were interviewed more than two weeks after treatment, which could have resulted in recall bias. the study was conducted in children less than five years old, thus the results may not be generalizable to residents older than five years. some agents isolated in the local laboratory, salmonella and shigella could not be confirmed by the national microbiology reference laboratory. the outbreak was propagated and affected all the residential areas in kadoma city. mixed etiological agents were responsible for the outbreak. knowledge on prevention and home treatment of diarrhoea was fair and did not differ between caregivers of cases and controls. the importance of providing adequate safe water, appropriate hand washing, exclusive breast feeding and good environmental hygiene were demonstrated to be protective against contractingdiarrhoea. the results of the study provided guidance for policy makers in responding to the outbreak, and formulating strategies to improve child health. based on the evidence from this study water purification tablets, municipal water trucking to residential areas, disinfection and repair of boreholes, and sewer unblocking was conducted in the affected communities. health education on importance of practicing good personal hygiene, boiling and treating water with water purification tablets before drinking and long term benefits of exclusive breast feeding was conducted, and is ongoing. all municipal clinics now have weekly updated diarrhoea reports. the national electricity distribution company installed dedicated electricity power lines to the municipal water pumping stations to maintain continuous water pumping. world health organization: diarrhea, factsheet number world gastroenterology organization practice guideline: acute diarrhoea where and why are million children dying every year? lancet zimbabwe government printers (now renamed printflow) kadoma city council offices kadoma city health department: cholera outbreak report kadoma city health department: cholera outbreak report assessing the performance of the early aberration reporting system (ears) syndromic surveillance algorithms. united states of america: naval postgraduate school a nationwide case-control study of escherichia coli o : h infection in the united states water: monitoring and assessment. available on url effect of washing hands with soap on diarrhoea risk in the community: a systematic review the problem of burst sewage pipes and sewerage outflows in east view suburb in kadoma city diarrhea due to rotavirus and probability of sewage contamination household water treatment and safe storage options in developing countries: a review of current implementation practices promotion of breastfeeding intervention trial (probit): a randomized trial in the republic of belarus risk factors for diarrheal disease incidence in early childhood: a community cohort study from guinea-bissau zimbabwe launches nutritional survey report. health harare risk factors for contracting watery diarrhoea in kadoma city i would like to express my sincere gratitude to my field supervisor, mr. d chirundu for his guidance and support, and to the staff and management at kadoma city council, and sanyati district for their support. special thanks go to the staff in the department of community medicine and mph field office for all the help they rendered. we would also like to express our profound gratitude to centres for disease control (cdc) zimbabwe for funding and technical input.many thanks go to all the caregivers for their consent to allow me to interview them. last, but not least, i would like to thank my family for social support throughout the project. the authors declare that they have no competing interests.authors' contributions bam: conception, design, acquisition, analysis and interpretation of data and drafting the manuscript. dc: conception, design, acquisition, analysis and interpretation of data and drafting the manuscript. ntg: conception, design, data collection, analysis, interpretation and reviewing of several drafts of the manuscript for important intellectual content. gs and lt :conception, design, key: cord- -by gxrd authors: pang, junjie; li, jianbo; xie, zhenzhen; huang, yan; cai, zhipeng title: collaborative city digital twin for covid- pandemic: a federated learning solution date: - - journal: nan doi: nan sha: doc_id: cord_uid: by gxrd in this work, we propose a collaborative city digital twin based on fl, a novel paradigm that allowing multiple city dt to share the local strategy and status in a timely manner. in particular, an fl central server manages the local updates of multiple collaborators (city dt), provides a global model which is trained in multiple iterations at different city dt systems, until the model gains the correlations between various response plan and infection trend. that means, a collaborative city dt paradigm based on fl techniques can obtain knowledge and patterns from multiple dts, and eventually establish a `global view' for city crisis management. meanwhile, it also helps to improve each city digital twin selves by consolidating other dt's respective data without violating privacy rules. to validate the proposed solution, we take covid- pandemic as a case study. the experimental results on the real dataset with various response plan validate our proposed solution and demonstrate the superior performance. c ovid- , an infectious disease caused by the most recently discovered coronavirus was identified in [ ] , december th . the virus has spread worldwide in less than three months, but infected more than . million people around the world and caused over , deaths . this novel coronavirus outbreak leads to severe illness and deaths in both younger and middle-aged adults, and it also critically affect people's daily lives. for example, almost million schoolchildren have been cut off from learning recently for avoiding direct exposure to this disease; thousands of people canceled their trips to reduce the risks of potential infection, etc. so far, there is still no specific antiviral treatment for covid- . fortunately, we observe that various active response plans have a clear positive effect upon preventing transmission from one person to another. one of the successful examples is in south korea . vt taking early, aggressive government response including establishing a large number of detection sites, isolating the infected patients in a very short time, and tracing contacts for searching the potential infected people with thoroughness, south korea controlled the spreading efficiently. thus, we observed that south korea has quickly flattened the epidemic curve after its first peak in february , and the daily cases declined to nearly zero after two months. the similar observation can also be found in many other countries, such as china, germany and the united kingdom. that means, if we response appropriately, the infection spreading can be effectively controlled. consequently, it is necessary to establish a paradigm to collect the historical data, and distinguish the effectiveness of various response plans. we also expect that such a paradigm could be used for other urgent city crisis. to obtain the above goal, city digital twin (city dt) has demonstrated a remarkable potential to offer the function of data collection, in-depth analysis and most important, it operationalizes real-world insights to asset performance and refine future actions [ ] , [ ] . in particular, a city digital twin is a virtual replica of the city that can provide digital view of city facilities, human activities and behavior, and other types of information about urban area. by keep interacting with the target environment, a city digital twin not only could automatically learn the patterns and generate useful insights from the historical data, but also continuously improve itself by verifying the automatic operations within the real world. eventually, a city dt enables interdisciplinary convergence in multiple aspects of city informatics, and offers increased visibility and machine intelligence for both human assisted decisions and automatic operations to facilitate city government and planners' decision-making. several successful attempts, including columbus consolidated government (columbus), digital twin city of atlanta, and virtual singapore, validate city digital twin's value for capture the complex spatial and temporal implications among multiple data source to optimize urban sustainability on traffic management, architectural planning and energy saving solutions. meanwhile, [ ] proposed a novel framework of disaster city digital twin with deep learning techniques, which presents the visions for a city dt based disaster management and further explains the advantages to response the disaster and crisis. thus, we expect that the city dt could be a promising solution to tackle current health crisis by simulating various response plan in this virtual system, and finally determine the proper actions to control the infection trend. note that, when we aim to construct a city digital twin to model covid- pandemic and generate the prediction of a specified response plan, we need to resolve the data sparsity challenge with considerations of privacy by following reasons. first, a city digital twin for health crisis like covid- may contain more sensitive information than other application scenarios, which imply the pressing need for privacy protection on the raw data. second, as each city constructing its own digital twin system, which means it could form an isolated data island. under such conditions, each city can only depend on a trail-error manner to control the pandemic instead of learning experience from others, which may result in delayed response or inappropriate operations. to resolve such problems, a collaborative city digital twin paradigm can be beneficial to alleviate the data sparsity issue. meanwhile, it is also helpful on pursuing an accurate prediction for choosing a better response plan. to this definitive end, we need to answer three primary questions: ( ) how to find a collaborative plan that can enhance the prediction results while not disturbing the interactions between city digital twin systems and the physical environment? ( ) how to ensure the collaborative solution can automatically generate different insights to adapt to different city digital twin system? ( ) how to provide the collaborative city digital twin paradigm with privacy protection guarantee? a straightforward solution is the distributed machine learning method with privacy protection guarantee, so that various city digital twin can upload their raw data to the central server to achieve a learning result based on data fusion results. however, the initiative data pre-processing stage of this plan could bring extra time expenses, and the centralized training manner is likely to have higher risks on privacy leakage and security issues. to address the above challenges, in this paper, we propose a federated learning (fl) [ ] based solution to bridge these separated city digital twin for covid- pandemic control, which is depicted in fig. . in particular, each city digital twin is a client in our fl paradigm. each client uses a sequence sequence (seq seq) model to generate the local forecasting model by historical conditions of covid- in targeted area. multiple city dts can cooperatively train a shared model on fl platform, only with local updates without exchanging the raw data. that is, each city dt can be improved by both local data and external insights from other city dts to make more efficient response operations. our contributions can be summarized as follows. • to resolve the data sparsity challenge for covid- pandemic management, we are among the first to propose a novel collaborative training framework for multiple city digital twin. • considering the various privacy requirement among different city dt, we utilize the federated learning techniques as our primary solution, which offers a parametersharing only concept for not disturbing each city dt's privacy rules. • extensive simulations with a real dataset reveal that the our proposed framework significantly improves the performance when compared with the single dt system. the rest of the paper is organized as follows. section ii introduces related works. the basic definitions and problem statement is presented in section iii. section iv explains the detailed structure of the proposed framwork. the experiments and results are analyzed in section v. finally, conclusion and future work are presented in section vi. historical insights for understanding the character of different epidemics and the prediction of spreading trends have been crucially crucial for epidemic control and prevention. several past studies applied artificial intelligence based models to these highly specialized domains and observed impressive multi-functional properties, such as the deep neural network based short-term and high-resolution epidemic forecasting for influenza-like illness [ ] , the semi-supervised deep learning framework that integrates computational epidemiology and social media mining techniques for epidemic simulation called simnest [ ] and epirp [ ] that using representational learning methods to capture the dynamic characteristics of epidemic spreading on social networks for epidemics-oriented clustering and classification. to appreciate why deep learning techniques are required, in this section, we briefly review several recent relevant works and their contributions in artificial intelligencebased urban epidemic control. deep learning based epidemic control: for the past decade, deep learning technique has been used in a variety of smart health areas, including disease prevention and monitoring, intelligent diagnosis and treatment systems, and health decision-making. recent breakthroughs in various disease modeling, forecasting, and real-time disease surveillance have convinced us that those applications mitigate the effects of disease outbreaks. given various application scenarios and objectives, deep learning based models can be different: a typical solution for localized flu nowcasting and flu activity inferring is argonet [ ] , which is a network-based approach leveraging spatio-temporal correlations across different states to improve the prediction accuracy. based on the information from influenza-related google search frequencies, electronic health records, and historical influenza trends, argonet uses a spatial network to capture the spatio-temporal correlations across different states and produces more precise retrospective estimates. instead of leveraging multiple data source like argonet, [ ] proposes a multi-task learning based model that only using user-generated content (web search data). they investigate both linear and nonlinear models' capability and find they can improve the disease rate estimates significantly in the case study of influenza-like illness. these successful attempts, however, are based on large scale data sources or plenty historical information of the disease with similar spreading patterns. that means, high-dimensionality, irregularity forms, noise, or sparsity problems are possible to affect these learning-based models' performance. such problems would be more serious when the smart health system needs to deal with unexpected infectious disease outbreaks like covid- , due to limited historical data and information. city digital twin: for most of deep learning based applications, the performance depends on the interaction with the physical world to generate data with high quality. to fill the data gap, digital twin is proposed as a virtual representation of a device or a specific application scenario, which can interact with the target environment to collect data continuously for real-time decision making. such a concept leads to the advancements in both urban computing paradigm and iot applications direct extending to smart city area recently, which termed as 'city digital twin'. it is a digital model of the physical urban environment, which collects information by hundreds of iot devices or public databases. it provides remote decision making and real-time insights about the physical asset's performance by utilizing machine learning and artificial intelligence techniques. it also serves as an essential role in addressing public health, urban planning, and environmental issues. the data streaming in the city digital twin model enables proactive remote monitoring to identify patterns and risks that foreshadow specific impending issues. several successful research attempts including disaster city digital twin [ ] , [ ] , energy management [ ] , and cityscale light detection and ranging (lidar) point clouds [ ] . furthermore, singapore [ ] and germany [ ] has launched the city-scale digital twin to monitor and improve utilities, which enhance the transparency, sustainability and availability of dt. federated learning: pandemic control and response are the significant challenges in the field of urban computing. however, recent research on digital twin is designed for the city resource management for a single urban area, and such application scenario often has enough historical data and multiple resources. unfortunately, the data resource could be the most challenging requirement for dt aiming at pandemic control, especially the unexpected contagious disease like covid- due to lacking enough experience and information. to maintain the advantages of dt and tolerate the data sparsity challenge, federated learning that allows multiple stackholders sharing data and training global model has become a preferred scheme. in the typical fl scheme settings, each data owner (fl client) engages in a collaborative training process without transferring the raw data to the others. through fl, the central server manages each client's local training updates and aggregates their contributions to enhance the global model's performance. several concrete scenarios include google's gboard, health ai and smart banking showing the advantages of federated learning in handling collaborative training issues and data difficulties among diverse data owners. therefore, we are motivated to utilize federated learning techniques to resolve the data sparsity challenges and design a collaborative city digital twin for covid- pandemic control. in this section, we propose our designed system model of city digital twin for covid- pandemic control. we first introduce the basic definitions, and then give the problem statement and explain the implementation difficulties. a city digital twin has three primary components: the physical environment of the city, a virtual replica describing the city's architecture, functions, behaviors, and active communications between the two for obtaining real-time spatiotemporal data from various infrastructure and human systems [ ] . in our work, we follow this typical architecture, and propose the city digital twin for covid- pandemic control using the following metrics: covid- infected number: the covid- infected number is the direct evidence to represent the infection status of a specific geographic area. in our proposed dt model, the infected number in the target area is represented by: area, time, number. response plan: for covid- pandemic control, various organizations and governments develop several local level or even a country-level operational plan to prepare for and respond to covid- . in our dt model, we use r i = (l i , t st , t end ) to represent a response plan, where l i is the location, with t st , t end denotes the starting time and end time of r i . the response plan includes day quarantine, domestic travel limitations, gatherings limits and stay at home, nonessential business closures, reopening plans, mask policy, etc. the effectiveness of different response plan can be varied, since it is may be affected by several external factor, such as a crowd gathers, adverse weather conditions or using vaccines. temporal effects: for our proposed dt system, the primary goal is to analyze the specific response plan, determine whether the historical plan will impact the future infection trend, to estimate the possible plan effects. in the process of building such a virtual replica for the covid- pandemic control, we observe the temporal effects is a critical factor when we aim to provide useful guidance on response plan selection. these temporal effects can be considered two types in our proposed dt system: temporal effects of historical infection numbers and selected response plans. temporal effects of historical infection numbers: the historical infection numbers are direct evidence to describe the correlation between past conditions and current infection status. in fig , we take historical daily case information of three states (nv: nevada, ut: utah, wi: wisconsin) as examples to illustrate the temporal effects of multiple factors. from the data of early march from three states, we observe an immediate impact of historical infection numbers since it leads to a continuously increasing number of infections until april nd, . such correlations play quite an essential role in explaining and predicting future infection trends. temporal effects of response plans: the choice of a specified response operation can also significantly impacts the number of infection. this impact could be immediate or delayed, which may depend on the strictness of that operation or people's acceptance. for example, in fig. , we observe that after taking a specified response plan, such as domestic travel limitations or gathering limits, the infection trend is decreased in the next several days. such impact could be complicated, since the -day time window, the time that a response plan starts to take effect, and paroxysmal public crisis may also with the definite goal of making the covid- pandemic under control, different local agencies in each city/region may choose their own strategy to meet their local requirements. such divergence is mainly caused by the fact that different cities could have other conditions or expectations so that the local agency tends to provide a different response plan considering several local intrinsic properties. for instance, area a, which is a thinly populated district with very low infection rates, would prefer to choose less radical response plan; while the another area b, where has more serious infection conditions, is very likely to choose a more strict response plan like restricting activities and closing facilities. obviously, such unsynchronized operations present obstacles to accumulating knowledge about providing accurate response guidance, since each city forms an isolated data island. furthermore, covid- , as an infectious disease with unknown cause, has exaggerated the situation due to lacking enough historical information and experience for dealing with the new virus. that means, each city can only obtain knowledge by trialand-error operation schemes for seeking an effective response plan, and the increasing time cost may lead to a delayed policy with poor performance. to resolve the above difficulties, we formalize this problem as a fl training problem using the fl approach to resolve the data sparsity challenge in city digital twin construction. thus, we propose to learning a objective function as follows: given multiple city dts d = d , d , · · · , d i that expecting collaborations and bounded with a local data sensing method to generate individualize data source s i, , s i, , · · · , s i,mi , our federated training problem is aim to optimize following function: where p i = mi m and the local objective f i (·) is defined by in this section, we present our proposed method utilizing fl as the collaborative platform for predicting a response plan's effectiveness, with considerations of temporal patterns and external factor impacts. specifically, we describe the baseline model using seq seq structure, and give the details of the proposed federated training process to help understand how every single city dt can be automatically improved by such collaboration. a typical city digital twin actively collects real-time data from infrastructure and human systems to obtain automatic decision making or possible future behavior predictions. hence, it is beneficial for tracking the progress of the infectious disease in real-time and accumulating information and knowledge at city scale. however, covid- is a novel coronavirus with incredible spreading speed, which means the city dt faces the challenge of making effective operations with very limited response time. under such circumstances, single city dt likely lacks experience to determine a well strategic preparedness and response plan quickly since each city dt has limited number of actions and observations. thus, we introduce fl as the primary solution to implement a collaborative training process, enabling multiple city dts to train a global model for response operation prediction collaboratively. federated learning is a novel distributed learning framework with a privacy protection guarantee. unlike previous research dealing with training data in a centralized manner, fl uses a parameter only concept to avoid disturbing each collaborator's privacy rules. thus, multiple collaborators can learn a common model as partners while preserving personal data on their own devices. in particular, for a new fl training task, ( ) the fl central server would train a global model for initialization, then distributed this model to the existing collaborators (clients); ( ) after receiving the global model, each collaborator use the local dataset to update the local parameter and generates the local updates; ( ) based on specified synchronization settings, all these updates are back to the fl central server for aggregation, and the global model is improved; ( ) such distributed updates iteration are from the above facts, we observe clear advantages of utilizing fl for establishing the collaborative city dts framework: (i) by the separation of local model training and global model updates, fl offers a strong capability to deal with the isolated data island problem between multiple dts; (ii) with enhanced privacy settings, each city dt can obtain the collaboration achievements without violating its privacy rules. in our proposed collaborative framework for multiple city dts (fig. ) , each single city dt system can reinforce itself by two ways: ( ) self-renewal mode by local updates: this mode is similar as the working updates of traditional digital twin system, which collecting real-time covid- conditions (historical infection numbers, external factors like crowd gathering, population age and vaccination) actively through on-device sensing, or using data source from various institutions like public health agency or hospital. ( ) jointrenewal mode by global updates: our proposed fl framework offers a platform for all city dts with willingness for sharing its experience and insights. by such collaboration, the single city dt can gather information from others to update the local model, which we regard as a joint-renewal mode in this paper. specifically, our works aim to simulate a response operation's performance for guiding choosing an appropriate response plan of covid- . under such a practical context, the joint-renewal mode can effectively complete the local models by utilizing other collaborator's updates. for example, suppose a city dt a decides to take a new response operation r i to deal with a crowd-gathering caused infection outbreak; at that time, city dt b, which have used the same response operation r i before, can broadcast its experience through the fl platform by uploading the local updates on time. then, after obtaining for the local city dt system, we utilize the gru based seq seq learning model with gated recurrent unit (gru) for local training, which is illustrated by fig. . the seq seq learning pipeline is one of the typical encoder-decoder structure to solve the general sequence to sequence learning problem with neural networks, which has well performance when input and the output sequences have unfixed lengths with complicated and non-monotonic relationship [ ] . the gru layer is a variant of recurrent neural networks (rnn) for better time-series data processing, and each gru cell only uses two data gates to control the data from processor: the reset gate r determine the information needs forget, and update gate z decides how the information needs to be updated. in particular, our proposed local city dt system using threelayer gru for the encoder part, which maps the history of sequences (the infection number of the target area and response operation) to latent representations. after the encoder part processing the history data of days, these hidden states pass to the decoder part. the decoder using gru and three full connected layer, which accept the hidden state from encoder as initial state and the expected response operation as input, while the output is the prediction of the infection number at next time unit. eventually, the local city dt would obtain the infection trend's prediction result in the next days. the federated training process aims to provide a collaborative training protocol without violating the privacy rules of each city dt, and the whole training diagram is depicted in fig. . this training process includes following steps: ( ) in the beginning, the fl central server trains a global model by pubic data source or voluntary data set from step : initialization step : local model training and upload step : aggregate and update global model step : deployment dataset and experiment settings of the framework. then, multiple aspects of experiment results, comparisons and analysis are provided, especially the comparisons between non-federated methods and our proposed method in terms of prediction accuracy. dataset description: we used the covid tracking project dataset and the coronavirus (covid- ) state actions dataset to conduct experiments. the covid tracking project dataset contains each state's daily epidemic data from the first case in the united states from january, to july, , including information on the number of nucleic acid tests, the number of confirmed cases, and the number of severe cases. the coronavirus (covid- ) state actions dataset mainly contains specific information about the policies adopted by various states in the united states during the epidemic, including the policy's name, the start time, and the end time. in this paper, we also need to consider other external factors, such as the change in the number of infections in each state in a time zone, the implementation of various response operations, etc. therefore, we combine the two data sets for our model training. in our combined dataset, • state name indicates the state where the current data is located. • date represents the current data time. • data − (t − , · · · , t + ) contains a total of days of epidemic data starting at time t ( days forward and days backward), and each day's data is determined by the number of people diagnosed and the current response operation. a one-hot vector represents every response operation, if it is selected, it is represented as ; and if not selected, it would be represented as . to eliminate the epidemic data's volatility and highlight the inherent time trend and periodicity, we use the moving average method to calculate the moving average of the number of infections for each day, and the moving window is set to . experiments settings and parameters we conduct all the experiments on the pytorch platform, and use pysyft [ ] framework for the implementation of our fl protocol. for the baseline model for local dt training, the encoder is with three-layer gru and the decoder is with three fully connected layer and a three-layer gru. we set the learning rates of the neural networks as . , mini-batch size as , and evaluate the accuracy of prediction results with mean square error (mse), which is defined as follows: in fig. , we show the comparison results of our federated solution and non-federated solution. it shows the difference of the loss value of both of the two models in states, each using the individual training method and federated learning method. for our federated learning model, fedavg is adopted as the aggregation algorithm, due to the considerations of saving communication resource. the selected response operation includes domestic travel limitations, gatherings limits and stay at home, nonessential business closures, reopening plans and task forces, statewide mask policy. as shown in fig. , in most states, the loss of epidemic prediction of fl training is much less than that of single dt models. this indicates that through fl training, each city dt can exchange the epidemic information of their own city to improve their dt model, so that the prediction performance for covid- trend under selected response operations maintains at a relatively high value. fig. shows the loss rate of the city dt model from six states (id: idaho, mt: montana, tx: texas, co:colorado, nd: north dakota, il: illinois) with the change of the number of fl clients (collaborators). the steel-blue line of each city dt in fig. represents the loss value of the prediction result based on single dt model that only rely on its own dataset, so that it will not change with the number of participating fl members. the dark-orange curve shows the loss value of the city dt model that training in the fl environment. when the number of people participating in the fl platform is increasing, it can be observed the performance has been gradually enhanced, since the information obtained by dt in each city has gradually accumulated. under such conditions, the prediction results have become more accurate. thus, the experimental results show that increasing the number of fl clients can effectively improve the training effect and reduce the prediction error of each single city dt. vi. conclusion in this paper, we propose a novel collaborative city digital twin framework based on federated learning techniques for covid- response plan management, with seq seq structure to better capture temporal contexts in historical infection data. the proposed framework shows that the collaborative learning of multiple city digital twin is beneficial for alleviating the data sparsity challenge, especially when the novel coronavirus management needs more data sources and highly strict privacy protection requirements. besides, the experiments validate our approach achieves better performance on the real dataset. in the future, we aim to involve more data sources (e.g., movement of people, seasonal changes, temperature, and humidity) to improve the performance of the proposed framework. coronavirus disease (covid- ) pandemic. website on the integration of agents and digital twins in healthcare health . : digital twins for health and well-being disaster city digital twin: a vision for integrating artificial and human intelligence for disaster management communication-efficient learning of deep networks from decentralized data defsi: deep learning based epidemic forecasting with synthetic information simnest: social media nested epidemic simulation via online semi-supervised deep learning ieee international conference on data mining, icdm epirep: learning node representations through epidemic dynamics on networks improved state-level influenza nowcasting in the united states leveraging internet-based data and network approaches multi-task learning improves disease models from web search social sensing in disaster city digital twin: integrated textual-visual-geo framework for situational awareness during built environment disruptions smart city digital twin-enabled energy management: toward real-time urban building energy benchmarking from lidar point cloud towards digital twin city: clustering city objects based on gestalt principles virtual singapore-creating an intelligent d model to improve experiences of residents, business and government urban digital twins for smart cities and citizens: the case study of herrenberg smart city digital twins sequence to sequence learning with neural networks a generic framework for privacy preserving deep learning key: cord- - plgjn d authors: boulton, chris; dedekorkut-howes, aysin; holden, meg; byrne, jason title: under pressure: factors shaping urban greenspace provision in a mid-sized city date: - - journal: cities doi: . /j.cities. . sha: doc_id: cord_uid: plgjn d urban greenspaces provide diverse ecosystem functions, services and benefits to residents. much commentary has been offered to date about citizens' demands for more urban greenspace. less attention, however, has been given to the ‘supply side’ pressures experienced by local government in delivering urban greenspace, particularly in mid-sized cities. greater attention to factors shaping supply is warranted, especially in the context of rapid population growth. by understanding how existing greenspace provision approaches can stymie the efforts of local government to meet citizens' needs, new approaches can be identified. this paper assesses several factors shaping urban greenspace provision in surrey - a city within the greater vancouver area. insights are derived from in-depth interviews with key stakeholders, public documents, and census and municipal data about parks and their context as a specific type of greenspace. our findings suggest that governance tools, economy and property markets, and financial and natural resources manifest as core factors influencing urban greenspace provision in surrey. a reliance on governance tools premised upon standards has created park provision paradoxes. treating greenspace provision as a largely technocratic exercise may be limiting surrey's ability to respond to changing politics, economics and population trends. we point to alternative approaches. once conceived as the domain of the gentry, parks and greenspace are now being reconceptualisedand advancedas solutions to multiple urban problems (for example, social integration, stormwater attenuation, and health promotion). adequate greenspace provision has emerged as one of the most important policy challenges facing cities across the world (haaland & van den bosch, ; kabisch, ; richards, passy, & oh, ; wolch, byrne, & newell, ) . globally, concerns with public health are driving renewed interest in parks, street trees, and other forms of greenspace for their positive physical and mental health outcomes (de vries, verheij, groenewegen, & spreeuwenberg, ; kardan et al., ; mitchell & popham, ) . greenspaces are increasingly regarded as essential urban infrastructure that can provide diverse ecosystem functions, services, and benefits. indeed, greenspace is now increasingly seen as instrumental for mitigating climate change impacts (including urban heat islands, flooding) and as a biodiversity refuge (byrne, lo, & jianjun, ; gill, handley, ennos, & pauleit, ; maimaitiyiming et al., ) . a key consideration here is whether existing approaches for park provision can meet these diverse demands. the answer partly depends on how approaches to provision are attuned (or not) to the contemporary political, economic, social and environmental challenges facing cities. in their systematic review of the literature on urban greenspace provision and supply, boulton, dedekorkut-howes, and byrne ( ) observed that the most often reported purpose of greenspace is recreation -regardless of greenspace type. other urban greenspace purposes include environmental (e.g. drainage, climate mitigation), social (e.g., amenity, health, food production, culture and heritage), and economic (e.g., transport) purposes. dilemmas for municipal urban greenspace managers arise when attempting to satisfy these multiple demands with limited resourcesespecially financial ones (ordóñez et al., ) . to date, research examining the spatial challenges of supplying urban greenspace has mostly focused on issues related to its accessibility (such as fan, xu, yue, & cen, ; rojas, páez, barbosa, & carrasco, ; stessens, khan, huysmans, & canters, ) and availability (kabisch, strohbach, haase, & kronenberg, ) . the complex systems and processes that determine how and when resources are allocated to urban greenspace are comparatively under-assessed. the experiences of park planners and managers 'at the coalface' of delivering municipal urban greenspace within the constraints of competing municipal services and infrastructure, such as roads and stormwater is understudied (with the notable exception of newell ( , ) ). what are the pressures associated with fastpaced urban development to support rapid population growth? this paper takes up the task of addressing these significant gaps in the literature by providing an 'insider's perspective' to urban greenspace provision. our study has sought to better understand how the complex challenges of providing urban greenspace are negotiated by local government, and to some extent the broader community in fast-growing cities. we employed a qualitative case study approach to examine two key questions: ) what factors shape urban greenspace provision at the local scale? and ) how are these factors resolved? we address these questions in turn. following a review of the scholarly literature about the factors that most influence urban greenspace, we describe our research method and case study area. we then synthesise the key findings about the factors influencing local government urban greenspace provision. we discuss our findings in the context of emerging themes and point to some important implications for urban policy and planning practice. we conclude by identifying some research limitations and propose directions for future research. a recent review of the academic literature focused on the provision of urban greenspace (boulton et al., ) revealed a range of factors at play, including governance tools and structures, resources (natural, financial and human), leadership (political and organisational), community engagement, markets and economies. the literature as explained below, suggests that these factors manifest themselves in different ways in different contexts, depending on variables such as the pattern of urban development, city size, and the involvement of not-forprofit organisations. in the broad sense, urban greenspace governance concerns "the processes, interactions, organisations, and decisions"; that is, the "complex area of human organisation and behaviour" (lawrence, de vreese, johnston, van den bosch, & sanesi, , p. ) . and, in their review of trends in urban forestry governance (as a sub-set of urban greenspace types), lawrence et al. ( ) offer a framework comprising: context, institutional framework, actors and coalitions, resources, and processes. in a similar vein, tacconi ( , p. ) defines environmental governance as "the formal and informal institutions, rules, mechanisms and processes of collective decision-making" highlighting its role in facilitating stakeholder influence and engagement. urban greenspace governance therefore comprises tools (policies, planning instruments and regulations) that help demonstrate the vision, purpose, and delivery goals of primary stakeholders (government and non-government) to other stakeholders involved in and/or concerned with greenspace provision (lawrence et al., ) . planning instruments are often cited for their role in facilitatingor in some cases frustratingurban greenspace provision and their alignment with policies for urban growth, densification, and green infrastructure, especially at the local scale (byrne, sipe, & searle, ; davies & lafortezza, ; haaland & van den bosch, ) . governance tools therefore need to be context-based and politically informed for decision-making about urban greenspace provision in a local setting. the most cited tools are the use of area-based and distance-based standards; many cities continue to rely on park standards such as provision ratios and percentages of land proposed for subdivision (harnik, ; jim, ) . resources shaping urban greenspace provision include natural resources, knowledge, information, and funding as well as delivery mechanisms, as recognised by lawrence et al.'s ( , p. ) urban forestry governance framework. studies to date have demonstrated that the availability and allocation of natural resources is fundamental to achieving greenspace provision. for instance, the quantity of greenspace within hong kong's urban footprint is exceptionally low when compared with other large chinese cities, due to the highly constrained geography of the city (steep vegetated slopes), high cost of land, and the extent of urban development (lo & jim, ; tang & wong, ) . in some rapidly growing cities, flood-prone lands (de sousa, ) and brownfield sitesincluding abandoned rail corridors and airportshave been adapted to public greenspace (kabisch & haase, ) . funding cuts for municipal service provision, including parks, have meant reduced resources (staff and financial) for park maintenance in europe including berlin (rosol, ) , the united kingdom (dickinson, bennett, & marson, ; mell, ) , and denmark (molin & van den bosch, ) . in the usa, residents of los angeles county with limited access to urban greenspace, have been further disadvantaged compared to other parts of the metropolis where not-for-profit agencies are effectively mobilised to secure limited grant funding to improve greenspace provision for residents (wolch, wilson, & fehrenbach, ) . in milwaukee, residents' access to public greenspace has been diminished through the sale of parkland for housing development by commercial enterprises, out-sourced park management to non-profits, and commodification of community gardens (roy, ) . resources associated with urban greenspace provision have therefore been found to be highly influential, especially those that are natural (availability of suitable land) or financial (capital funding for land acquisition, facility development, maintenance, operations, and programming). provision of urban greenspace is strongly shaped by markets and economiesfrom global to local scales, with socio-spatially differentiated outcomes. for instance, watson ( ) has observed that the impact of markets and economies on cities rarely benefits or engages socio-economically disadvantaged communities. similarly, vinodrai ( ) has noted scholars' concerns about amplified social disconnections between the creative and working classes within the emerging knowledge-based, creative economies. coiacetto ( ) has also reported the complexities of property markets and the development industry, including the reliance on funding (loans) which can be difficult to access and can frustrate delivery of new urban infrastructure especially targeted for community purposes. development interests at a global and national scale (for example, investor appetite for risk) can determine greenspace provision at the local level, with paradoxical outcomes. in hermosillo, mexico for example, financial in-flows, rather than city planning policy, shaped development and services provision in comparatively (dis)advantaged neighbourhoods, despite the need to address inequitable distribution (lara-valencia & garcía-pérez, ) . similarly, property development in japan has resulted in greater access to urban greenspace for more affluent residential areas of yokohama (yasumoto, jones, & shimizu, ) . and in the middle east, global markets driving oil and gas production impelled rapid urbanisation and diminished urban greenspace provision for some greater doha residents (hashem, ) . development activity therefore often has an impact on the availability of financial resources for urban greenspace provision and who benefits from the in-flow of such resources. this concise review suggests that urban greenspace provision depends predominantly on adequate governance tools and available resources. this is especially true for small to mid-size cities (boulton et al., ) . limited financial support and comparatively reduced global investment mean such cities experience the challenges of urban growth more acutely. the net result can be reduced greenspace provision especially for densifying cities (haaland & van den bosch, ). yet there is presently a gap in the scholarly knowledge about how urban greenspace is provided in mid-sized non-capital cities, a gap that our research aims to address. to answer our earlier questions, we conceived a case study research design that sought to illuminate the perspectives of urban greenspace managers, planners, and decision-makers (internal and external to the local government) supported by documentary evidence. we undertook a case study of a local government area to examine the phenomenon of urban greenspace provision using qualitative methods. drawing upon the lead author's experience over a decade as a municipal greenspace manager, themes and concepts were initially developed about the factors that shape urban greenspace provision. these themes and concepts were evaluated and refined against the academic literature to establish a framework of factors for testing through the case study. the selected case study site is a mid-size, noncapital city experiencing rapid population growth and urban densification, on the periphery of a major metropolitan region. as the central data source for our case study, in-depth interviews were conducted about urban greenspace provision, supported by relevant public documents drawn from municipal plans, policies, and strategies (current as of april ). interview participants with either a role or a demonstrated interest in the provision of urban greenspace in the case study area, were identified from a purposive sample of potential interviewees. a total of participants were interviewed by the lead author between april and june , using open-ended questions (appendix a). the interviewees were classified as one of five types: community representatives (residents and local academics) (n = ), elected officials (politicians) (n = ), executive managers (n = ), managers (n = ) or officers (n = ), and assigned a unique numerical identifier for anonymity. in terms of their familiarity with our case study area, interviewees had either been employed by the municipality, were a resident or an academic researcher with a demonstrated interest in our case study area and/or its citizens, or had provided service to the municipality. our interviewee profile was mostly male (n = ) senior employees with extensive experience (executive managers, managers, and community representatives with a range to years; officers with a range of to years; citizens or researchers in the region with a range of to years). interviews were conducted in multiple locales including: municipal offices, a public library meeting room, on a university campus, or in the case of some retired interviewees, in their home. the average duration of the interviews was min (ranging from to min), which were captured using two digital voice recorders. recordings were transcribed using an online digital voice-to-text transcription service (temi.com), manually edited by the interviewer, then provided to each interviewee for confirmation and editing as desired, prior to analysis. interview transcripts in the first instance were analysed using leximancer (version . ) as a visual-first analytic method. leximancer facilitated inductive thematic analysisidentifying prominent themes and concepts, and their relationships to each other, within the central research focus of urban greenspace and park provision, and consistent with its application by angus, rintel, and wiles ( ) and sotiriadou, brouwers, and le ( ) . using nvivo professional (version ), interview transcripts were then coded to further examine prevalent themes, emerging issues, and predicted factors influencing greenspace provision (appendix a). descriptive codes were prepared as a theorydriven approach using content analysis (churchill, ; decuir-gunby, marshall, & mcculloch, ) ; codes were applied at both implicit and explicit levels (sproule, ) . consistent with previous greenspace provision research (for example, davies and lafortezza ( ) and roy ( ) ), documentary materials were sourced as secondary data to triangulate the in-depth interview data. these included relevant municipal and provincial legislation, policy instruments, relevant excerpts from local media (churchill, ; cope, ) , as well as census and municipal data. surrey is a canadian non-capital city, experiencing fast growth. the city is part of a larger urban metropolitan region with a municipal government that seemingly celebrates and values significant urban greenspace provision. located within the greater vancouver regional district, surrey is approximately km southeast of vancouver, bordering washington state, usa to the south. with a local government area of km (city of surrey, ) surrey is spatially the largest municipality within the greater vancouver regional district and is characterised by six distinct urban centres: whalley, guildford, newton, fleetwood, cloverdale, and south surrey. approximately one third of the city's area is within the . million-hectare agricultural land reserve comprising public and private lands that can be farmed, forested or remain vacant (diamond head consulting ltd., ; wiese, ) (fig. ) . outside of the agricultural land reserve, surrey's urban containment boundary is "consistent with metro vancouver's regional growth strategy " (city of surrey, , p. ) . while vancouver has attracted considerable attention for its urban policy and development, much less is known about the municipal areas in vancouver's shadowthose neighbouring municipalities arguably shouldering the burden of urban growth (see holden & scerri, ) . surrey is also one of canada's fastest-growing municipalities (see fig. ) with an annual average growth rate of . % between the most recent census years ( and ) and the fastest growing municipality in the metro vancouver region (city of surrey, ). the current estimated population of , (city of surrey, ) is forecast to reach , by (city of surrey, ) at a projected annual growth rate of . %. surrey's vision is of "a greener, more complete, more compact and connected community that is resilient, safer, inclusive, healthier and more beautiful" (city of surrey, , p. ) than the present day. "infrastructure and facilities" are key to surrey's official community plan, including recreation facilities, parks and greenways (see fig. ) that "knit surrey and its neighbourhoods together" (city of surrey, , p. ) . greenspace provision for surrey is based on the aspirational goal of a park area provision ratio of . ha per residents, supported by a walkshed/travel-shed of - m from multi-family residences (city of surrey, , p. ). council's parks division (part of the parks, recreation and culture department) is responsible for surrey's municipal urban greenspace provision including planning, research, design, capital works delivery, operations, maintenance and programming (city of surrey, b) . with ha of parkland to serve the residential population in (city of surrey, ), surrey was exceeding its goal of . ha of parkland per residents in by ha per residents (city of surrey, , p. ) , even before including the non-municipal and other greenspace provided by metro vancouver and the province of british columbia. however, the pace of population growth has exceeded the rate of parkland acquisition, opening a gap that has steadily widened for almost a century (fig. ) . curiously, surrey has generally managed to achieve a provision ratio ranging from . to . ha per residents over these decades (fig. ) despite a decline when resources were scarce during global crises of wars and the great depression during the early half of the th century. urban greenspace provision in surrey was later spurred on in the first instance by legislative amendments to establish a parks commission ( ), appointment of a recreation director ( ), a parks administrator ( ) (treleavan, ) and again in the s at a time that coincided with surrey being declared "a city of parks" (robert bose, personal communication with lead author, june ). at face value, this suggests that surrey is highly 'effective' at keeping pace with an aspirational standards for urban greenspace, where 'effective' implies actively acquiring more land for parks in pursuit of the aspirational target ( . ha per residents). this prompts several questions about the approach to urban c. boulton, et al. cities ( ) greenspace provision in surrey, such as: what does this goal accomplish; is this the only measure employed to determine effective urban greenspace provision; and are other criteria considered? there are already some early signals that continued population growth fuelled by high in-migration, is potentially undermining surrey's success with urban greenspace provision in maintaining and even exceeding the target ratio of parkland to residents. for instance, surrey's once minimum target of . ha per residents (city of surrey, ) has now transitioned into an aspirational goal in responding to the mounting pressure to provide urban greenspace in the face of rapid growth (city of surrey, ) . the benefit of having a provision ratio as an aspirational goal for surrey is that it still provides a clearly defined vision for urban greenspace provision as a metric for reporting performance to the community. while there are some positive outcomes of striving for a larger quantity of parks this also raises some questions. at what cost to the quality of surrey's collective urban greenspace, longer term maintenance, and park programming do more parks come? are these under threat with realising an urban greenspace target? despite the pace of growth, rate of urban development, and likely inflow of economic resources to support new infrastructure from such investment, is surrey weakening in its ability to deliver urban greenspace? what caused surrey's decision to change course from . ha per residents as a minimum target to becoming an aspirational goal for urban greenspace provision? kotter ( , p. viii) suggests that success often delivers complacency; complacency is the opposite of urgency which is at the heart of leading change in "making a challenging leap into some new direction". in search of some revelations to this perplexing conundrum, we now turn to the perspectives from some of surrey's key players in the urban greenspace realm to determine if surrey is indeed facing an emerging crisis, and in doing so, we examine what factors scaffold, and perhaps threaten, the city's greenspace achievement. statistics canada, , , , . six prominent themes and multiple concepts that help explain urban greenspace provision in surrey emerged from our analysis of the interview data using leximancer (see table ). the analysis suggests that the themes of urban greenspace and parkland (our research focus) are related to several other themes comprising one or more concepts: local government, property development, budgets, surrey and its citizens, municipal administration, and the elected council (fig. ). our analysis revealed these themes in three clusters: ) urban greenspace, parkland, and local government; ) budgets and, property development; and ) surrey and its citizens, the municipal administration, and the elected council. in this case, the budget and property development themes both clustered together and sit more closely to 'urban greenspace' and 'parks'. the remaining themes of elected councils, municipal administration, and surrey and its citizens, were likewise clustered, yet with greater distance from urban greenspace and parkland. it is the core factors (budgets and property development) that are more directly linked to and in closest proximity to urban greenspace and parkland that we examine here. further analysis of the interview data in nvivo revealed multiple factors of influence that include resources, governance (tools and structure), community expectations, economy and markets, political leadership, community expectations and organisational culture, among these themes and concepts. consistent with boulton et al. ( ) interviews revealed that proportionally, resources and governance tools were the prominent factors determining urban greenspace provision. property market and economies, governance structure, organisational culture, and political leadership likewise were evident. 'community expectations' was also a dominant factor that emerged from our case c. boulton, et al. cities ( ) study data (see fig. ). overall, our findings indicate that governance tools (planning legislation and policy), financial resources (budgets and money), and property development (including the property market) were distinctly at the heart of urban greenspace provision in surrey. it is these factors which are essential to realising and enabling its lawful delivery, which we therefore refer to as the core factors (fig. ) . in order to provide a comprehensive and in-depth discussion of this group of factors identified, we have focused solely on the core factors in this article with the remaining supporting factors to be reported separately. we now address each of these core factors in turn. interviewees reported a range of governance tools that shape urban greenspace in surrey, stemming from the provincial level. central to these tools is british columbia's local government act, the primary legislation providing the means of planning and financing service delivery for municipalities at both regional and local levels. surrey's urban greenspace provision is also shaped by the metro vancouver regional growth strategy mandating the urban containment boundary (metro vancouver, ) . the local government act also underpins metro vancouver's provision of several regional greenspaces including tynehead regional park ( ha) and surrey bend regional park ( ha) (greater vancouver regional district, ; . however, manager reported that surrey traditionally has not included these two metro vancouver parklands in their inventory "all of which add very substantially to parkland provision in surrey", and hence explains how surrey is maintaining a high provision ratio (fig. ) despite a widening gap between population growth and parkland acquisition (fig. ) . in british columbia, municipalities are required to obtain public approval under certain circumstances including ) borrowing money for major projects (s. community charter and s. local government act) and ) disposing of land (s. community charter and s. local government act) (province of british columbia, columbia, , columbia, , . the few participants that identified a referendum (also known as 'assent voting' -see province of british columbia, ) as a governance tool, spoke positively about its impact on surrey's urban greenspace provision. officer and elected official each spoke of the value this legislation offered in protecting parks from disposal or amended use exemplified by the cases of sunnyside acres and green timbers urban forest. elected official offered that "to remove a park from dedication you have to conduct [a] referendum and that would require the vote of all surrey residents… a referendum on parks is… avoided at almost all costs because… they could [not] succeed. people value the parks". as progressing proposals for parkland acquisition, facility development or parkland disposal is at council's discretion, council runs the risk of potentially exposing council intentions that may be contrary to community expectations. surrey's policy instruments -by-laws and resolutions -include the official community plan as well as other documents formally adopted by a council vote (union of bc municipalities, ). surrey's -ha park system (city of surrey, ) is therefore provided in accordance with the official community plan (city of surrey, ), informed by strategic plans including parks, recreational and culture strategic plan - (city of surrey, b), biodiversity conservation strategy (diamond head consulting ltd, ), and greenways plan (city of surrey, ). surrey's official community plan provides for city parks, community parks, neighbourhood parks, nature preserves, and habitat corridors (city of surrey, , p. ) . surprisingly, despite its title, the greenways strategy (fig. ) was seldom mentioned in the context of the city's urban greenspace provision. officer attempted to explain: "it [is] a network that allows people to make green choices in terms of how they move around the city. they [are] not necessarily 'green' from a landscape point of view." most interviewees at least correlated biodiversity with urban greenspace. officer and officer reported that biodiversity had recently been incorporated in the parks recreation and culture strategic plan - (city of surrey, b) as a type of table frequency of themes and their associated concepts identified in leximancer and factors shaping urban greenspace provision in surrey, canada from interview data. the intent of dccs is to support infrastructure for new development, and despite clear guidelines from the province and council policy, several interviewees were unclear about how dccs are being collected and applied, and how they can be, and are, used for urban greenspace provision. some interviewees seemingly perceived that dccs are either intended to be, or currently are the sole funding source for acquiring parkland. this included executive manager and community representative who held similar perspectives that development revenue collected could not keep pace with land acquisition to achieve an aspirational goal of . ha per residents. having a generous supply of greenspace, and continuing to pursue more, comes at a significant cost. surrey is challenged in finding the governance tools, financial and land resources to support new and important initiatives. for example, the biodiversity conservation strategy and greenways plan seek to provide even more land ( to ha) for biodiversity, and for future neighbourhood parks in addition to the -ha existing park system. manager revealed that these policies (the biodiversity conservation strategy and the greenways plan) "all point to this need to acquire a lot of land for biodiversity purposes … and yet council does [not] know how they are going to find the money for it". elected official demonstrated that there is political awareness of the scope and scale of necessary future acquisition and while acknowledging funding as an impediment like the managers, they offered a solution in the form of new charges and a levy "dedicated solely for the purpose of acquiring natural biodiverse parkland". as a governance tool, dccs are nested within a framework set by the local government act and provide a source of revenue and land resources for municipalities, additional to property tax, donated land, and inter-governmental funding partnerships. dccs are reviewed annually and are calculated based on residential dwelling units at the application phase of a proposed development and collected at either the sub-divisional approval or building permit stage depending on the type of development (city of surrey, a). dccs are then retained temporarily in a reserve fund to contribute to council's capital works program (land acquisition and/or works) (province of british columbia, ) . unfortunately, just having the tools does not mean the revenue is sufficient or even available; it is a political decision to increase dccs. manager and officer observed the dilemma facing elected officials between their desire to encourage development by keeping costs low and collecting enough revenue to provide the services required by that new development. the political decision to provide more revenue could soon exceed the authority of surrey's elected council as it approaches its maximum borrowing capacity, requiring public approval. but can more revenue ever solve the problem? "the speed at which the land prices have changed… dccs certainly do [not] increase in the same ratio and speed… [this] is the biggest barrier for us by far" (officer ). while dccs were reported by manager and manager to be reviewed annually, officer and officer both suggested that due to the lag time between calculation and adoption to eventual collection and parkland acquisition (which could be at least five years), dccs are still undervalued resulting in an under-funded parkland acquisition reserve. this is a strong indicator that the economy and markets are another significant factor in shaping surrey's urban greenspace provision -the next factor we examine. despite an annual parkland acquisition budget of approximately $ million acquiring - ha a year, surrey's staff responsible for providing urban greenspace reported that there is still not enough money or land. municipal resources are highly contested at the best of times. in the face of new and emerging global issues including the coronavirus pandemic , the international monetary fund predicts a record global recession (gopinath, ) which means that financial resources for municipal greenspace provision will be under even greater pressure. as our interviews revealed, urban greenspace provision in surrey is already highly impacted by the economy and markets at varying scales. at the heart of this issue is the pressure that comes with land speculation and investment both by developers and the local government itself. interviewees reported market pressure c. boulton, et al. cities ( ) manifesting in multiple ways: as land speculation in anticipation of rezoning to high-density land-use -especially on the edge of the alr, in developers' behaviour and capacity to negotiate better community outcomes during the planning process, and in the council's seemingly hopeless pursuit to overcome surrey's funding source and land acquisition program being out-paced by escalating land values. in response, the council undertook land-banking (acquiring land in areas where zoning will change, and land values will therefore increase). community representatives , and opined that this had further inflated local property values; conversely staff reported their frustration with limited funding for land acquisition preventing the city's practice of land-banking, reflected by executive manager and officer : we were able to do a bit of land-banking, so we [would] go into areas of a city [that] we knew were developing in the future and try to buy property when it was super cheap, which is great in theory… [however] we just can[not]… even keep up with what we need to buy today. there [is] just no chance of land banking. the very act of land-banking by land speculators, developers and the city of surrey is pushing property values even higher. the result is that the city can no longer afford to participate in this activity. greater vancouver's agricultural land reserve provides both a challenge and an opportunity to developers and planners in the context of urban greenspace with the pressure of urban growth. community representative reported investors using acquired lands for temporary uses such as golf courses, anticipating development opportunity through a modified urban containment boundary. likewise, elected official acknowledged the financial gains for property owners concerned where neighbourhood concept plans had been implemented adjoining the agricultural land reserve. among the interviewees, elected officials were especially aware of the pressure experienced by developers challenged to be flexible to provide greenspace contributions, when facing temporal and financial constraints associated with borrowed capital for real estate investment. elected official explained "the pressure on them to fight the planning department for… dedica-tion… becomes a battle for every inch because the margins… are so much tighter". elected official offered "developments being approved that go… really cheek to jowl with existing green spaces… [cause] huge tension between the interests of the development industry and… the need to acquire parkland". despite regional planners' intentions, pursuing more land within the agricultural land reserve for future parkland coupled with neighbourhood planning adjacent to the urban containment boundary is adding to land value inflation. officer reported "areas in south campbell heights… [and] hazelmere escarpment… [are] both outside of the urban containment boundary… but the city is advancing applications to change that". the agricultural c. boulton, et al. cities ( ) land reserve is at greater risk in light of council's parkland acquisition adopting a land-banking approach. interestingly, others have suggested that "ongoing pressure is what the alr [agricultural land reserve] is subject to and what it is designed to resolve" (cameron, harcourt, & rossiter, , p. ) . the tensions around developer negotiations, land shortages, fiscal constraints, and untenable community expectations are driving the need for leadership and innovation in urban greenspace provision. only two interviewees redefined greenspace to include parks, tree canopy, regional and provincial greenspace, and land for biodiversity. manager viewed parks and greenspace provision as a "matrix" that includes a collection of lands for biodiversity conservation and other city purposes, as well as private greenspace. likewise, manager contemplated, "but as we densify… the pressure on… parks… we need to revisit… how that land is utilised and maximised for the use of it". the paradox of how local government officers approach urban greenspace provision is illustrated by the comments of executive manager and manager about the dilemma of funding capital works versus maintenance perpetuated by pursuing more parkland. manager advised, "our [maintenance] funding is [not] increasing as quickly as our number of assets… our service levels are going to be dropping and… the public… blowback will get to a point where there [is] more pressure to increase taxes". here manager alludes to the hidden costs of providing new parks; capital expenditure typically accounts for a minor portion of the whole-of-life cost of municipal assets which includes annual maintenance, operations, depreciation, and asset renewal. this point was further reinforced by executive manager explaining the operational budget requests to support capital expenditure on urban greenspace: "we are not funded to the level that we would like". this means that acquiring more urban greenspace in pursuit of achieving a standard further contributes to the accumulating level of deferred green asset maintenance and renewal, the risk of existing asset deterioration, and eventual failure. our interviews revealed that there are practical challenges to pursuing an aspirational goal using a provision ratio. pressure is mounting upon staff and their budgets with pursuing more land, despite evidence that the city cannot afford to maintain and replace existing assets or develop new ones. elected officials, on the other hand, are under pressure to modify governance tools to facilitate development due to limited land resources for development within the regional urban containment boundary. while the pressures associated with factors at the core of urban greenspace provision for the city of surrey -the property market and economies, natural and financial resources and governance tools -are building, they are not yet at a point of crisis: "the potential complete failure in the reproduction of systemic relations" (gregory, johnston, pratt, watts, & whatmore, , p. ) . in the context of municipal urban greenspace provision, the crisis is likely to be that phase when provision falls well short of community expectations. this is then the point when urban greenspace provision actions are highly reactive, urgent and expensive to implement. thus the time to consider alternative approaches for providing urban greenspace is now -before the "blowback" (when the community reacts and demands political action to address the situation) -at a period when efforts can be proactive, considered, and implemented in an economical manner at a manageable pace. surrey's official community plan acknowledges the value and role of the full spectrum of surrey's greenspace resources, their opportunities, value, and the gaps but parkland acquisition remains a priority in pursuit of a provision ratio. british columbia's local government act provides opportunity and potentially more flexibility to deliver urban greenspace, providing that "the assessment of the need for and enjoyment of park and open space by the different land uses must be justified" (province of british columbia, , p. . ). dccs can be used for providing parkland acquisition and improvement as well as drainage facilities (province of british columbia, ) . this points to a problem with naming greenspace "parkland" and the assumptions that come with it about being mostly for recreation. surrey is seemingly limiting itself and its powers to maximise the use of dccs. this further presents a risk that the city is missing opportunities to address the emerging dilemma of an unfunded biodiversity conservation strategy. as surrey has yet to provide a funding strategy to implement their biodiversity conservation strategy, there is a risk of community perception that the city is not planning with "authenticity", or in a democratic manner, representing public expectations (zukin, , p. ) -in this case, endorsing a plan without providing a budget to support its delivery. community representative revealed this sentiment when discussing the role of this plan in decision-making: "[environmental] activists … have a very high level of frustration of how planning processes are going in the city when it comes to trying to protect these significant areas". the unfunded biodiversity conservation strategy requiring even more land is further adding to the pressure on the city's financial resources and elected officials to demonstrate their commitment and interest in delivering this strategy. the demands from environmental groups to repurpose parkland acquired for recreation/sport to parkland for conservation purposes in order to retain tree canopy is increasing the pressures on the city's parkland acquisition program. surrey is experiencing a widening resource gap between available land and funds -a situation unlikely to change in the short to medium term when global markets and the economy influence the city's growth and urban greenspace provision. this resource gap will add to the widening gap between population and parkland growth rates (see fig. ). within this context, striving for a provision ratio of . ha per residents does have some benefits overall, but seems highly problematic -especially for surrey when ) there is already an abundance of other types of greenspace that is not factored into these calculations, ) according to our interviewees, this standard is not likely to be realised into the future, and ) the local government is financially under-resourced to develop and maintain even its already acquired greenspace to the standard expected by its citizens. the drawback of concentrating available financial resources for acquiring more parkland is that surrey has less resources to improve the quality of urban greenspace by developing, maintaining and improving parkland and facilities. less parkland acquisition could therefore provide more quality urban greenspace, providing that it can be distributed to ensure equitable access. the key lessons for urban greenspace policymakers, practitioners, and researchers revealed through the examination of the challenges facing surrey, are instructive for considering alternative approaches concerning the core factors identified by our research. for instance, governance tools should be developed and implemented in a more collaborative and coordinated manner across all levels of government to ensure that communities are provided with an adequate quality and quantity of urban greenspace with equitable access, and critically, commensurate with current and future needs. for example, stakeholders from municipal, regional, and provincial levels should be collaborating on policy development and amendments to address emerging concerns such as surrey's flexibility in applying development cost charges to help realise the city's biodiversity conservation strategy. drawing on the insights about financial and natural resources, urban greenspace provision must also be conceived and delivered in a manner that optimises existing land resources first and foremost, to sustainably support the broad spectrum of urban greenspace functions, and embraces whole-of-life asset management. this could incorporate informal urban greenspace, street landscape, and cemeteries for instance, within surrey's urban greenspace inventory. finally, those responsible for urban greenspace provision must optimise the opportunities presented by property markets and changing economic conditions in an economically, environmentally, and socially sustainable manner. this might incorporate council's collaboration with the development industry to identify innovative opportunities for urban greenspace provision in the form of green roofs, green walls, enhanced street trees, and landscape areas (including water sensitive urban design infrastructure). adopting these principles may in fact offer a starting point in realising a better approach to providing urban greenspace as an alternative to simply pursuing more parkland. we commenced this paper by identifying concerns about how approaches to urban greenspace provision are attuned (or not) to the contemporary political, economic, social, and environmental challenges facing cities. we sought to answer two questions: ) what factors shape urban greenspace provision at the local scale? and ) how are these factors resolved? in the first instance, our research has identified a range of factors that shape urban greenspace provision by examining the case of surrey, bc. surrey is one of canada's fastest growing cities, with a population on track to reach almost , before the middle of the st century. surrey has been provided a bounty of urban greenspace through a legacy of urban planning initiatives at multiple levels of government and financial resources to acquire new parklands; but funding for acquiring urban greenspace to support biodiversity conservation and to develop and maintain existing urban greenspace is still scarce. we have revealed that for a city experiencing pressures of rapid growth, three factors are at the heart of urban greenspace provision: governance tools, financial and natural resources, and economies and property markets. the lessons from our surrey case illustrate the relevance of timing: property development is relative to market demand, which means that delivering urban greenspace requires infrastructure (not just land) to support the needs of the existing community. our case study has generated valuable insights about the complex systems and processes that determine when and how resources are allocated for urban greenspace provision, within the constraints of competing municipal services and infrastructure, such as roads and stormwater. the central argument to this paper is that the current approach to urban greenspace provision of relying upon governance tools does not acknowledge the challenges of supplying urban greenspace. this is a complex dilemma and one not simply resolved by marshalling more resources to meet demand or just preparing a policy/plan. the contributions of our research are manifold: ) it reveals supply side insights of local government planners, managers, and decision makers on the challenges of urban greenspace provision; ) it examines an important knowledge gap in the research to date with understanding the quandaries of non-capital, mid-sized cities experiencing rapid growth; and ) it reveals the range of factors that shape urban greenspace and how they operate in this context. the framework of (core) factors and how they manifest in this case is an innovative and important contribution that illustrates insights from key actors within local government. the implications for urban greenspace policy, practice, and research are that urban policy and planning approaches need to be cognisant of these factors, how they differ spatially and temporally, and facilitate local variance for planning to be effective. as core factors, governance tools, property markets and economies, and natural and financial resources are closest to municipal urban greenspace provision, particularly parks (fig. ) . changing the approach to urban greenspace provision starts here and it is this new insight that is novel and contributes to the literature. there is another set of factors that helps shape urban greenspacethe supporting factors which also need to be examined: community expectations, political leadership, governance structure, human resources, and organisational culture (fig. ) . the relevance, complexity, and depth of these factors suggest that they too play an important role in shaping urban greenspace provision; a role that warrants further examination to fully appreciate the complexity of urban greenspace provision, not only in surrey but in rapidly growing cities globally. what are the community expectationsespecially those of developers and residentsand how are these influencing urban greenspace provision? does this provide additional pressure? this task is too complex to appropriately examine in depth and within the limitations of this paper. it is imperative that future research examine not only how these supporting factors shape urban greenspace provision in different contexts, but critically explores developers' perspectives and experiences as key stakeholders. while surrey may seem unique in its specific human geography, its european history, and concentration of new residents determined by current immigration from south asia, means that the city also shares similarities with other mid-sized cities grappling with rapid population growth, urban densification, and the desire to secure more urban greenspace. canadian cities are not alone in confronting the challenges of managing rapid urban growth and delivering urban greenspace to support the needs of healthy communities; challenges further compounded by the covid- pandemic when countries with advanced economies -including canada -are facing major economic downturns predicted at > % (gopinath, ) . the characteristics and interrelationships of these core factors (economies and markets, limited resources, and governance tools) exert pressure on the approach to urban greenspace provision. it is important that this phenomenon is examined and understood in the local context; these factors vary both spatially and temporally. during a global crisis of lock-down and social distancing measures in response to the covid- pandemic, provision of adequate urban greenspace to support citizens' mental and physical health and well-being is more important than ever before (beck, giles-corti, & ivers, ; mell, ) . understanding these factors should help unlock innovative solutions to optimise all urban greenspace and achieve broader ecosystem services and benefits that we have come to expect from them, rather than persisting with planning tools that principally target one type of urban greenspace (i.e. recreational parks). we need solutions that are cognisant of ongoing whole-of-life asset costs associated with development, facility maintenance, and renewal, and resilient to economic downturns that apply increased pressure on contested municipal financial resources. this is essential to sustainable urban greenspace provision. simply allowing the pressure to build and being complacent about the need to change the greenspace provision approach to one that can be adequately resourced (financially) to meet the spectrum of a city's natural greenspace needs, may compromise the greenspace legacy of tomorrow's cities. the authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. suggested improvements and additions to drafts. all errors remain of course, our own. making sense of big text: a visual-first approach for analysing text data using leximancer and discursis physical distancing is here for a while -over experts call for more safe walking and cycling space. the conversation factors shaping urban greenspace provision: a systematic review of the literature residents' understanding of the role of green infrastructure for climate change adaptation in hangzhou green around the gills? the challenge of density for urban greenspace planning in seq city making in paradise: nine decisions that 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accessibility and quality: a gis-based model as spatial decision support for urban ecosystem services in brussels developing environmental governance research: the example of forest cover change studies a longitudinal study of open space zoning and development in hong kong surrey today. surrey, canada: surrey museum and historical society economic change in canadian cities: innovation, creativity, and the knowledge economy seeing from the south: refocusing urban planning on the globe's central urban issues food thought. abbotsford, canada: the british columbia agriculture in the classroom foundation parks and park funding in los angeles: an equity-mapping analysis urban green space, public health, and environmental justice: the challenge of making cities "just green enough longitudinal trends in equity of park accessibility in yokohama, japan: an investigation into the role of causal mechanisms naked city: the death and life of authentic urban places this work was supported by an australia awards endeavour research fellowship department of education and training, australia (recipient id: - ); in-kind support was provided by the city of surrey and simon fraser university, canada. we also thank professor neil sipe and the anonymous reviewers of this article, particularly those who provided extensive feedback about our research and advice on supplementary data to this article can be found online at https:// doi.org/ . /j.cities. . . key: cord- -vd etd authors: tucker, jennifer l.; anantharaman, manisha title: informal work and sustainable cities: from formalization to reparation date: - - journal: one earth doi: . /j.oneear. . . sha: doc_id: cord_uid: vd etd informal workers produce economic, social, and environmental value for cities. too often, policy elites, including those promoting sustainable cities, overlook this value, proposing formalization and relying on deficit-based framings of informal work. in this perspective piece, we bring critical research and community-produced knowledge about informal work to sustainability scholarship. we challenge the dominant, deficit-based frame of informal work, which can dispossess workers, reduce their collective power, and undercut the social and environmental value their work generates. instead, thinking historically, relationally, and spatially clarifies the essential role of informal work for urban economies and highlights their potential for promoting sustainable cities. it also reveals how growth-oriented economies reproduce environmental destruction, income inequality, and poverty, the very conditions impelling many to informal work. rather than formalization, we propose reparation, an ethic and practice promoting ecological regeneration, while redressing historic wrongs and redistributing resources and social power to workers and grassroots social movements. worldwide, about two billion people work informally, more than one-half of non-agricultural employment in most regions of the global south. informal work includes a range of income-generating activities outside of state labor protections and the wagerelation. these workers generate value and contribute to the realization of the sustainable development goals (sdgs). for instance, grassroots recyclers provide essential urban-environmental services, diverting waste from landfills and enabling recycling, while street vendors support food security as they bring life, vibrancy, and protection to urban spaces. , formal economies rely on and appropriate this value. for instance, waste pickers reduce the cost of public waste management services by diverting recyclables away from landfills. informal firms produce goods cheaply, reducing costs for formal, capitalist firms who depend on these inputs. yet, in many places, urban policy frames informal work as problematic or even criminal. desiring reform, policy makers and city officials invest formalization with supercharged powers to reduce poverty, increase productivity, clean and order urban space, and produce self-reliant economic subjects. the international labor organizations' (ilo) centenary declaration for the future of work prioritizes formalization, , whereas the sdgs, particularly sdg , assert that formalizing the informal will produce economic growth and decent work (safe and adequately paid work that respects labor and human rights). but while policy elites push formalization, the economic reality is moving in the opposite direction. the characteristics associated with informal work-low pay, job insecurity, and temporary, contract-based employment without benefits-are becoming generalized, as seen through the ascendance of the gig economy. despite persistent desires for formalization among policy elites, informal work is a permanent feature of contemporary economic life. informal workers produce economic, social, and environmental value for cities, value that is often underestimated or overlooked because informality challenges mainstream assumptions about what work looks like. indeed, informal work is excluded from dominant economic imaginaries, widely shared assumptions of economically productive activity. the dominant economic imaginary associates work with a regular wage paid by an employer in a private establishment, rather than in public space, even as the work of so many looks very different. using the term imaginaries reminds us that core economic assumptions are ideas made up by people. economies are made real in and through social relations in human societies. they are always cultural and contextual. feminist geographer gibson-graham coined this term critiquing the restricted ideas of valuable work and corresponding notions of valuable people that currently dominate. commonly, informal work is defined by what it lacks. this deficit lens of informal work persists because policy elites ignore critical and community-based research on informality and overlook the knowledge and capacities of informal workers. the deficit-based frame of informal work can dispossess workers, reduce their collective power, and undercut the social and environmental value their work generates. new modes of thinking and acting can, in turn, animate new economic imaginaries and relations. building on our research in india and paraguay, amplifying critical informality scholarship and centering the knowledge produced by workers' organizations, we assert that by thinking historically, relationally, and spatially, and redistributing power and resources to workers, we can move beyond formalization to a frame that centers decent work, ecological health, and reparation for uneven legacies of harm. only when it redistributes resources and power to informal workers will formalization help address social and environmental inequities. although we write to sustainability theorists and practitioners, we emphasize that the main protagonists of transformation must be social movements led by frontline communities, that is, the communities who are both most harmed by the crises of climate, covid- , and economic injustice, and therefore have most at stake in realizing alternative worlds. in this article, we analyze why dominant economic imaginaries devalue informal work, assessing the implications for sustainability initiatives. we then outline our proposals about thinking historically, relationally, and spatially. we emphasize that moving toward sustainable cities requires understanding the dynamics of racial capitalism, which produces both poverty and environmental degradation. we offer reparation as a framework to guide the action of development practitioners and scholars, illustrating our argument with existing practices and transformational proposals. we conclude by reflecting on the hard road ahead, underscoring the need to resource, support, and learn from frontline workers' organizations and social movements. indisputably, the st century is characterized by worsening ecological crises alongside a deficit of decent work. although our focus is informal work, we note that waged employment does not necessarily protect against poverty, as million us workers classified as the ''working poor'' can attest. moreover, reducing poverty by expanding decent work has historically intensified environmental exploitation. nearly all countries with national ecological footprints within the sustainability threshold have very high levels of working poverty, indicating that the traditional means of alleviating poverty through economic growth produces environmental degradation. admirably, the sdgs seek to decouple decent work from ecological extraction, promoting both livelihoods and sustainability. however, the transformative potential of the sdgs is compromised by an economic imaginary that misreads the key drivers of both poverty and environmental degradation and ignores empirical and theoretical research demonstrating that economic growth cannot be decoupled from environmental degradation in today's economies of extraction. [ ] [ ] [ ] [ ] studies finding modest success in a few exceptional countries to decouple economic growth from greenhouse gas emissions do not consider other forms of environmental degradation, such as land use change and unsustainable freshwater extraction. indeed, the sdgs remain captive to ''fairytales of eternal economic growth,'' a mindset decried by youth climate activist greta thunberg at the un climate summit. the sdgs privilege technocratic planning and propose win-win scenarios, downplaying the trade-offs between economic growth, social development, and environmental protection. furthermore, the sdgs ignore compelling evidence that redistribution, not growth, is the key. , in their current form, the sdgs are a trojan horse, smuggling in unpopular and problematic neoliberal economic policies, including the erasure and enclosure of informal livelihoods. scholarship over the last years has offered changing perspectives on the nature and value of informal work. , early dualist frameworks proposed that modernization would expand formal employment and starve the informal sector. since then, researchers have documented intense linkages across supply chains that crisscross sectors designated as formal and informal. there is great variation between domains of informal work, from unregistered ''petty commodity producers,'' supplying cheap inputs into capitalist production processes and reducing costs for formal firms ; to own account operators, such as waste pickers and street vendors; to informal employees, such as day laborers or domestic workers. following insights from critical anthropologists, geographers, and planning scholars, we argue that the informal and formal are relational categories whose boundaries are determined by culture and power, pointing to deeply intertwined domains of economic practice. [ ] [ ] [ ] although we find informal and formal to be analytically imprecise categories, we retain them here because of their political significance in policy making to draw lines between valued and devalued economic activities with consequences for both workers and sustainability initiatives. in spite of this research, the dominant economic imaginary devalues informal workers as unproductive and problematic. informal work is compared against the yard-stick of the ''standard employment relationship,'' signifying a unionized, waged worker, despite calls to decenter the wage. , yet secure, well-paid employment with benefits is the exception, not the norm, a form of work limited to so-called developed countries for a few postwar decades. , the deficit-based definition of informal work holds across deep ideological divisions. neoliberal economists see low productivity and ''low levels of human capital,'' labor scholars emphasize the lack of state protections, such as social security or workplace protections, whereas orthodox marxists see the lack of class consciousness and historical agency because of their structural location in economies of ''informal survivalism.'' the tenacity of the deficit definition echoes dynamics that render invisible other value-producing domains, such as women's unpaid household labor, social reproduction more broadly, the essential inputs of nature and noncommodified economies of reciprocity. informal work produces economic, social, and environmental value that sustains lives and urban environments. at the same time, formal economies rely on and appropriate this value. this article explores this central contradiction: the informal is framed as problematic and targeted for reform even as formal economies benefit from and appropriate the value produced by informal workers. to sketch a counter-story, we underscore the considerable creativity of workers facing calamitous state disinvestment in collective wellbeing. at the same time, we do not romanticize these economic words. informal livelihoods are complex and contradictory, combining individualism and community, care and exclusions, competition and collaboration, autonomy and drudgery. , formalization is shorthand for a range of policies seeking to align economic activities with the law, either changing legal codes or reforming behaviors. this can include decriminalizing informal work, licensing businesses, requiring tax compliance, enforcing labor and environmental regulations, promoting certain kinds of spatial order, or eliminating competition from firms or workers with lower costs of business because of noncompliance. however, legalistic formalization projects, rooted in eurocentric urban knowledge, fail to understand the diverse realities of most cities. whereas legalist policy frameworks value rule-following for its own sake, critical researchers demonstrate the anti-poor biases of law, the criminalization of poverty, and tendencies to leave the legal transgressions of elites unpunished. urban life in many cities is marked by dealmaking and provisionality. residents use, sidestep, and transgress legal codes depending on situational exigencies and a ''transversal'' relationship to law. contrary to expectations, formalization does not necessarily solve problems for informal workers, nor make those economic activities more valuable. formalization deriving from a legalistic, deficit-based framing can dispossess workers of livelihoods, reduce workers' collective power, reiterate stigmas associated with informality, and undercut the social and environmental value that informal work generates. if projects devolve risk and responsibility for providing basic services without resourcing worker organizations, formalization can increase the exploitation of informal workers. , the emphasis on formalization in the sdgs reflects the role of powerful, well-funded civil society organizations, largely from rich and middle-income countries , and too often lacking representation of workers. official ''invited spaces of participation'' often limit dissent, discourage critical examination of underlying economic imaginaries, and carry unspoken, exclusionary codes of acceptable behavior that reflect elite norms, values, behaviors, and codes of dress. not uncommonly, policy elites interpret expressions of worker power as illegitimate, such as waste pickers blockading dumps to protect their livelihoods. , yet often, contentious politics are needed to interrupt the status quo and offer alternative political imaginations. to illustrate the importance of informal work, we draw examples from street vending and waste work. in diverse cities, grassroots recyclers toil in difficult conditions while facing intense stigma, quotidian harassment, and even deadly violence. , yet their labors build functioning value chains for recyclables, generating income for themselves and materials for other markets as they also enable environmental behaviors among elites and provide the only opportunity for recycling in many cities. [ ] [ ] [ ] [ ] [ ] [ ] although there is great variability, the informal sector can rival formal sector material recovery rates. informal sector recyclers have irreplaceable knowledge crucial to maximizing value in waste. , [ ] [ ] [ ] [ ] indeed, policy elites now herald informal recycling as already-existing circular economies critical for sustainability transitions. similarly, street vendors enable access to cheap food despite battling a host of ''everyday challenges.'' their work contributes to sdg : making cities and human settlements inclusive, safe, resilient, and sustainable. furthermore, informal livelihoods provide crucial incomes, critical to sdg : zero poverty. worldwide, waste picking sustains some million people, while similar numbers work as street vendors. but informal work means more than an income. informal economies are complex systems of redistribution; community networks that can be tapped in times of need. in contexts of state disinvestment and chronic job scarcity, informal worlds provide a buffer against outright destitution. indeed, against stereotypes, most monetary transfers that keep poor communities afloat occur within poor communities, not between the rich and the poor. for instance, a montevideo recyclers coopera-tive transferred a share of their collective daily earnings to members unable to work due to sickness or care-taking obligations. in times of crisis, informal responses offer ''collective security mechanisms,'' , illustrated by street vendors providing food to communities under a strict covid- curfew in india. while informal care networks help cities recover from disasters-both slow-moving and spectacular-intensifying inequalities are challenging these systems of social provisioning. finally, we emphasize that the conditions of waged work are not universally preferable to informality. the once-a-month payday, inflexible work schedules, and long hours of waged work can clash with the pressing daily needs of those living precariously. in rio's largest dump, waste pickers valued the flexibility, autonomy, and sociability of the dump, cooking together, socializing, and adapting schedules to their needs, working more when necessary and less when possible. building just and sustainable cities requires reexamining how the informal is conceptualized and acted upon by mainstream development actors. we propose decentering formalization as a primary goal of initiatives such as the sdgs and organizations such as the ilo. for formalization to address social and environmental inequities it must redistribute resources and power to informal workers. this can be realized through an ethic and practice of reparation, which seeks to reimagine and recreate socioecological relations from a full acknowledgment of the injustices of the past as they live into the present. , we advocate reparation over justice because dominant, liberal notions of justice center the individual, foreclosing consideration of histories of harm and denying the need for collective redress. we articulate three modes of thinking to reconceptualize informal work and animate an alternative, ethical economic imaginary: thinking historically, thinking relationally, and thinking spatially. yet, it is not enough to think differently. urban economies come into being in and through webs of social relations that tie people to particular modes of laboring, living, creating, and consuming. thus, we also argue for concrete actions oriented toward social and environmental justice: redistributing wealth and power, strengthening worker's organizations, and recovering politics from technocratic capture. this approach underscores the interlinked nature of liberatory thought and action, or praxis. , these ways of thinking and acting are diametrically opposed to dominant academic and policy-making trends in which informal workers are treated as ''passive objects of study'' or which operate through benevolence, a stance which reproduces racial and imperial hierarchies of power. this agenda cannot be designed and executed from the top down and must emerge through an authentic collaboration with workers. such collaborations are only possible by expanding our notions of the agents of urban and sustainable development, which, in turn, requires radical humility on the part of ''experts,'' while valuing workers' knowledge, power, and political forms. without such a reframing, historically marginalized groups might well be excluded, exploited, or expelled from clean and green cities. [ ] [ ] [ ] [ ] thinking historically thinking historically clarifies racial capitalism's core logics of accumulation, appropriation, and exploitation as incompatible with decent work or sustainable societies. decent work and ll one earth , september , clean environments for some have always required oppressions, exclusions, and exposure to harm for others. , racial capitalism as a frame explains how capitalism incorporates and depends on the ''devaluation of nonwhite bodies.'' from its beginning, capitalism tended to ''differentiate-to exaggerate regional, subcultural, and dialectical differences into 'racial' ones.'' , thinking historically with racial capitalism demonstrates the common patterns through which exclusion, exploitation, and disposability are racialized processes, even if racialization works differently for mexican immigrants in the us, members of scheduled castes such as dalits in india, indigenous guatemalans, or afro-brazilians. indeed, racialized groups are more likely to engage in undervalued and invisibilized forms of work (as are women), including care and informal work. today, covid- has launched the term ''essential workers'' into our public vocabularies, making visible how essential work is often underpaid and under-protected. thinking historically shows how capitalist economies treat essential workers as disposable by constructing myths that devalue or render invisible their work. from enslaved africans picking cotton in the us south to reclaimers recycling the waste of consumer capitalism, a core logic twins the essential and the disposable. this lethal logic organizes formal and informal economies. in indian cities, most frontline, essential workers keeping the city clean during covid- lockdowns are dalit, scheduled castes and tribes, or muslims. [ ] [ ] [ ] yet, the state fails to equip them with adequate protective gear. striking amazon workers also report inadequate health protections at facilities with outbreaks, and have responded by organizing over job actions in the us in march to june . meanwhile, amazon ceo jeff bezos amassed an additional $ . billion during weeks in march and april as the pandemic took hold. these examples illustrate that treating people as disposable is not an aberrant behavior of a few bad apples but a common, accepted means to reduce costs and concentrate profits. indeed, in the us, the standard employment relation was made through racial and gendered exclusions. the wagner act-the cornerstone new deal expansion of labor protections-excluded both domestic employees and agriculture workers, legally barring both groups from organizing. these exclusions were a ''proxy to exclude most black employees'' in the south as they also reflected biases devaluing ''women's work.'' congress excluded these workers in an explicit compromise to appease the racism of conservative southern legislators. looking further back, the rise of the waged worker as the presumed norm and aspirational horizon of all has a long, bloody history. early industrial capitalism needed people willing to work for a wage in brutal factories. in england, this required the enclosures movement, two centuries of dispossessing peasants of commonly held lands and criminalizing ''poaching'' and other means of self-provisioning. this long history normalizing the wage also rendered informal work ''invisible to science.'' similarly, self-sufficient indigenous communities steadfastly refused waged work. forcing participation in waged work required centuries of sustained settler violence: land theft, the criminalization of indigenous culture, and attacks on community means of subsistence, for instance, the intentional decimation of buffalo in the us plains states. , indeed, racial capitalism refuses to recognize non-capitalist lifeways as legitimate or pro-ductive. marking these communities as ''uncivilized'' or ''indolent'' helped justify violence and dispossessions. current land grabs and other processes of rural dispossession create mass migration to cities and urban populations seeking a foothold in informal economies. indeed, many waste pickers in bangalore are migrants from bengal, dispossessed of their land-based livelihoods by urban expansion and neoliberal development. capitalist firms also appropriate unpaid or devalued inputs, a processes of ''cheapening'' land, labor, care work, and the fruits of nature, such as food and energy. some appropriations are overtly violent: theft of indigenous land, plantation-based slave economies, or ongoing murders of indigenous land defenders in latin america and beyond. others are harder to see as cheapening rests on abstract ideas of value and its lack. for instance, capitalism appropriates the ''free gifts'' of nature: energy, natural resources, and raw materials. these ecosystem services-uncounted, invisiblized but absolutely necessaryare valued at %- % of global gdp. the free services of nature also partially absorb the wastes of consumer capitalism. the global atlas of environmental justice tracks more than , cases of communities fighting to protect land, water, forests, and livelihood from economies of extraction and privatization. the sdgs, for their part, propose delinking environmental destruction from economic growth, ignoring capitalism's core logics of appropriation and cheapening. furthermore, capitalism insulates markets from public accountability because of the abstract idea that private-sector economic decision making is separate from matters of public concern. cut off from democratic control, the private sector peruses short-term profitably for elites over collective wellbeing and the sustainability of life on earth. relational thinking shifts our practices of study and intervention ''from 'the poor and poor others' to. relationships of power and privilege,'' a framing we borrow from the relational poverty network. it also helps us see the economic, social, and environmental value of informal work and the ways it subsidizes formal economies. the forces that reproduce environmental destruction, inequality, and exclusion are multiscalar and multidimensional: deregulated economies, tax rebellions by the privileged, corporate tax-evasion and off-shoring, and uneven landscapes of investment (and disinvestment). [ ] [ ] [ ] fifty years of neoliberalism-a variant of racial capitalism characterized by austerity, deregulation, and financialization-has undermined the redistributive function of the northern welfare states and hamstrung burgeoning social state capacities across the global south. economist robert reich calls this the ''succession of the successful,'' as rich communities renege on contributing to public goods, turning instead to privatized housing, education, and health that most families cannot afford. the tentative and uneven gains in reducing inequality in the postwar decades have been swept away by the rise of the superrich, in which the top % controls more wealth than the bottom %. yet, from sociological ''cultures of poverty'' research to social entrepreneurship bootstrap schemes aimed at reforming the poor, much scholarship and action persists in blaming the poor for their poverty or focusing interventions in poor communities, leaving ll one earth , september , untouched key domains responsible for inequality and environmental harm. thinking relationally helps show how capitalism predictably produces poverty and inequality, the very forces that make informal economies necessary. given this, generating decent work and building sustainable cities requires transforming structural economic forces that much exceed the bounds of a particular informal economy. relational thinking highlights how informal workers provide ''invisible subsidies'' crucial for the social reproduction of capitalism, from waste pickers metabolizing post-consumer waste to the businesses in dharavi, an informal settlement outside mumbai, recycling plastic, tanning leather, weaving fabrics, and producing pottery worth as much as $ billion each year. relational thinking also demonstrates the connections between spaces of poverty and landscapes of wealth. middle class and rich consumers depend on the cheap, often informal labor of the monetarily poor, who clean homes, build high rises, metabolize waste, and lower consumption costs by lowering the costs of production. thinking relationally draws attention to the resource-hoarding, overconsumption, and disproportionate political power of the rich as major drivers of environmental harm. it also underscores how the modest welfare gains in the post-war era in north atlantic countries relied on massive wealth transfers from the global south (previously colonized) to the global north (in most cases, imperial powers). egyptian economist samir amin tracked one of these transfers, called unequal exchange. in addition to declining terms of trade, workers earning low wages in the global south buy expensive goods produced by higher paid workers in the global north, and vice versa, such that northern countries capture uncompensated value from the global south. in , the estimated value of this south-to-north transfer was $ . trillion, more than times the value of foreign aid moving in the other direction. on a more local level, poor communities are targeted as sources of revenue through official and extra-legal channels. a us department of justice report found that police officers in ferguson-under pressure to meet citation and arrest quotas-targeted black residents for minor, even fabricated infractions in what one anthropologist called a ''shake-down operation.' ' in other cities, street vending necessitates non-compliant activities. in response, officials harass and evict vendors, demanding bribes, imposing fines, and confiscating merchandise. in cochabamba, bolivia, these practices are so common that vendors call police officers ''the hungry ones'' (los hambres). relational thinking exposes how the rule-breaking behavior of state officials (and elites) is often tolerated, whereas the necessary infractions of the poor are criminalized. finally, thinking relationally clarifies the sources of environmental harm, thereby identifying which countries and which social groups bear responsibility for redress and reparation. , environmental justice research demonstrates that political-economic processes concentrate environmental harm in poor, racialized communities, protecting spaces of privilege. emphasizing the scale of environmental harms, ecologists and environmentalists propose we are in a new geologic age, the anthropocene, in which anthropogenic climate change and environmental destruction are earth-transforming features and system-wide threats. but culpability is not evenly distributed. environmental destruction and climate catastrophe result from our political-economic system, not an undifferentiated ''humanity'' or a timeless, unchangeable human nature. it is the consumption of the middle classes and elites that produces dirty cities and a majority of urban greenhouse gas emissions. the consequences of climate catastrophe concentrate in the global south, even as the global north is historically responsible for producing most carbon emissions. instead of the anthropocene, it is more honest and politically enabling to call our era the capitalocene, a frame that names the culprits undermining the conditions for human society. , thinking spatially thinking spatially sheds light on the social processes that allocate authorization and formalized status. elite groups, usually richer and whiter, have more social power to write their interests into law and more power in contests over the best uses of urban space. spatial thinking helps identify the underlying struggles to control space and economy that often drive formalization projects. state officials manage vendors with a range of laws, codes, tacit agreements, and other unofficial strategies. , too often, vendors are viewed as encroachers or criminals while punitive state policies disregard their needs. media accounts and city officials describe vendors as outsiders or as an ''invasion'' from which the city must ''retake'' space, pursing policies which expel the urban poor from desirable urban spaces. exclusionary policies are pervasive and evictions constant and violent. unfortunately, formal recognition does not always protect street vendors. in monrovia, officials harassed vendors even after a memorandum of understanding extended formal recognition. relocating vendors to formalized markets can also have negative effects. , in bogotá , relocated vendors gained better working conditions, but the move weakened their organizations and their incomes fell. in ciudad del este, paraguay, a municipal formalization project divided vendors, demobilized vending associations, and exposed vendors to ''dispossession by formalization.'' behind any campaign to ''clean the streets'' are competing ideas about the best uses of urban space. these visions are not neutral or objective. captive to the growth imaginary, market forces and state policies define ''highest and best use'' as activities that increase property values or create profit opportunities for formal firms. the dominant economic imaginary associates work with private spaces, coding public spaces for recreation, cars, pedestrians, and shoppers. consequently, urban zoning and regulatory practices often fail to support public space as sites of work. however, informal workers often must work in public. when vendors break the rules to work, they then are accused of being predisposed to unlawfulness, an accusation that codes structural inequalities as a question of culture or individual disposition. spatial imaginaries go beyond constructing public work as problematic. in the us, until the early s, sidewalks and streets were multi-use spaces. sidewalks supported working vendors, circulating pedestrians, celebrating residents and politically active citizens. in los angeles, the notion that sidewalks should prioritize pedestrians solidified through anti-immigrant campaigns targeting the livelihoods of chinese vendors. across latin america, colonial spatial imaginaries construct particular racial groups as belonging to particular spaces: cities are for whites and mestizos whereas indigenous communities are imagined as belonging to rural areas. in bolivia, officials racialized space, interpreting popular markets as unruly, rural incursions into cities, a precursor to attempts to remove or criminalize them. in ecuador, similar policies sought to expel indigenous ecuadorians from quito's historic center, ignoring that rural communities needed the income earned by their family members in the city. policing the line between work, nuisance, and crime is also about asserting control over valuable resources. as resourcestrapped cities move to ''modernize'' and formalize recycling, they often privatize waste management, privilege capital-intensive waste management systems, and enclose the materials that are claimed by waste pickers as livelihood inputs. [ ] [ ] [ ] this ''rational-modernist model of urbanization'' can create a ''vicious circle of competition'' for resources. formalization also requires framing trash as valuable, that is, adopting the knowledge work of waste pickers who saw value where officials saw trash. indeed, the discursive construction of the informal as a problematic space in need of reform is a precursor to imagining sites that can be enclosed and privatized. in contrast to official logics, street vendors and waste pickers value urban space by how it sustains life. when vendors and waste pickers carve out spaces for livelihood they are producing important urban commons, claiming urban space for ordinary workers. indeed, the challenge of informal workers in many places is precisely that they question growth and market-driven notions of what public space should be for and who should decide. from formalization to reparation thinking historically, relationally, and spatially clarifies the processes that co-produce both precarious work and ecological harm. decentering formalization, we advocate for reparation as an ethic to orient the actions of development practitioners and policy makers. our debt here is to the black radical tradition, scholars and activists proposing collective redress for the unspeakable violence and thefts of slavery, legacies that live into the present. [ ] [ ] [ ] following w.e.b. du bois, the ethic of reparation activates memory against the forces of willful forgetting that deny history and deep relationality. we are inspired by the black radical tradition's expansive, future-oriented political imagination and its call to remake economic and social relations from the roots up. ''reparation ecologies'' add an imperative to heal the false nature/society divide, locating socio-economic relationships within living ecologies. both lines of thinking emphasize redistribution: of resources, land, work, and the labors of care. although formalization targets workers or the economies that sustain them for reform, the field of action promoted by reparation is much broader, including the forces producing inequality and environmental harm. reparation acts horizontally, centering communities most harmed by fomenting worker power, repairing historic injustices, and redistributing social power and resources to the grassroots. reparation can also help us acknowledge the long history of assent to exploitation that structures scholarship and practice. the moment is ripe for clear thinking and bold action. the convulsions to work and life precipitated by covid- offer a rare opportunity to enact transformational change. of course, entrenched structures of race/class power are invested in extraction economies, wielding considerable resources to push for exclusionary, unsustainable modes of urban development. only empowered social movements led by frontline communities have the force to contest these elite power structures. for this reason, we call on development scholars and practitioners to invest in worker power, embrace contentious politics, relinquish power over knowledge production, and develop accountable relationships with grassroots social movements. against assumptions that informal workers are unorganizable, and despite many challenges, informal worker organizing is powerful. , collective action takes many forms, from member-based organizations (mbos) to workers organizing from other identity roles, such as mothers or migrants. informal workers organize for different demands: protecting access to markets, defending public resources, expanding citizenship rights, demanding social protection, or advocating for infrastructure improvements. , , indeed, collective action by informal workers changes urban policy. in ahmedabad, india, the organization self employed women's association (sewa) helped pass the protection of livelihood and regulation of street vending act while in lima, vendor organizations won pro-vendor policy at the city and national level. organizing by waste pickers forced a sea change in how policymakers understand these workers. once universally viewed as a nuisance or a criminal element, today, the un frames informal waste workers as ''any city's key ally.'' a study of latin american countries found that worker organizing was fundamental to establishing inclusive recycling policies. reversing trends of privatization, several latin american cities have partnered with waste picker organizations for doorto-door waste collection. in brazil, ''solidarity recycling'' includes over worker organizations as partners in the national solid waste policy. the city government in bangalore, india recognizes informal recyclers with occupational identity cards while organizing in durban cut out middlemen and increased income for reclaimers by %. development organizations should resource informal worker organizations, promote supportive regulatory environments, and support the urban commons built by informal workers. this requires resisting the razing instinct of rational-modernist urbanization that tears down informal spaces, instead upgrading in situ, safeguarding community ties, and respecting the rights of the poor to live centrally and participate in urban life. specific action plans must emerge in collaboration with grassroots organizations, such that here we seed ideas for reparative policies, rather than propose blueprints. worker-run cooperatives improve livelihoods whereas mbos build collective power. across levels of government, policy makers should resource these organizations, invest in mbo bargaining capacity, and seize opportunities to open up spaces for negotiations in diverse forums: everyday, ad hoc, and policy and statutory negotiations. , when cities reorganize waste systems, they can meaningfully include grassroots recyclers, pay waste pickers for services, , and provide work spaces. redistribution-across scales-is foundational to reparation, as it recognizes that markets unjustly concentrate wealth, neoliberal policies under-resource public goods while actually existing electoral politics concentrate social power. public budgets are statements of social values. currently, states overinvest in the military, jails, and policing, or in building infrastructures that cater to the consumption desires of elites. we must continue to insist that the resources for just and sustainable cities exist. cities must prioritize public provisioning of systems of care and ''universal basic services'' such as housing, healthcare, childcare, education, and sanitation. , redistribution can help re-value informal and other forms of invisibilized work, reducing inequality. inequality drives unsustainability, both by promoting conspicuous consumption and forcing poor people to over-exploit resources. , thus, addressing inequality through redistribution is critical to achieving environmental sustainability. here, we highlight some bold proposals scaled to the enormity of today's existential challenges: universal basic income, the global green new deal, the red deal, and care incomes. by delinking labor, income, and development, these reparative policies foster more just ways of organizing work, time, and life. in , reverend dr. martin luther king promoted a guaranteed income to further racial justice and activate the creative powers of human labor freed from the compulsions of (low) waged work, a call echoed five decades later by pope francis in his easter address. these ethical injunctions are now backed by evidence from finland, where modest income supports improved wellbeing and life satisfaction. envisioned to emancipate the economy from fossil fuels, the global green new deal offers concrete plans to decarbonize the economy while redressing the historic injustices that concentrate vulnerability to climate harms in poor countries and communities by insisting that climate culprits finance the transition. visionary indigenous organizers go further with a red deal that defunds prisons, policing, and militarism, freeing up the resources for indigenousled visions of ''liberation, life, and land,'' invoking decolonial calls for ''a world where many worlds fit.'' feminist degrowth scholars propose care incomes, payments to recognize and compensate the socially reproductive work that sustains life and community. currently ignored in gdp accounting, care work is largely carried out by women and marginalized social groups and thus care incomes have the potential to redress historical exclusions and benefit informal workers. [ ] [ ] [ ] conclusions today, life-sustaining earth systems are under existential threat. as covid- devastates informal livelihoods worldwide, mass layoffs plunge unprecedented numbers of workers into economic hardship. ethical economic imaginaries undergirding new realities are thus an urgent necessity. sustainable development initiatives such as the sgds admirably seek to promote both environmental sustainability and decent work. yet, promoting poverty alleviation and ecological wholeness through economic growth is like trying to squeeze water from stone. these approaches are seductive. they promise to decouple growth from environmental damage through innovation as they promote policies that leave inequalities in wealth and social power largely untouched. they ignore that inequality is a key driver of environmental harm. thus, we insist, our pathways forward must recognize the co-constitution of poverty, inequality, and unsustainability. the necessary transformations are daunting. challenging entrenched structures of elite power is so difficult that some caution incremental change and propose only band-aid solutions to ameliorate some of the most acute forms of suffering caused by racial capitalism. against this limiting pragmatism, we argue for transformational change and encourage sustainability scholarship and practice to take an active role in promoting reparation. policymakers and sustainability researchers should learn from the critical and community-produced research on informality. we must move beyond formalization and diagnose the shared drivers of decent work deficits and environmental degradation. thinking historically, relationally, and spatially reveals how the value produced by informal workers subsidize urban economies and ecologies, even as racial capitalism predictably reproduces job scarcity, income inequality, and poverty, the very conditions that impel many to informal work. ethical economic imaginaries combined with ethic of reparative action can offer pathways toward sustainable, equitable cities by investing resources in the only social force capable of contesting elite power structures: workers and social movements on the frontlines. women and men in the informal economy: a statistical picture waste pickers and cities sidewalk, st edition (farrar street vending and public policy: a global review informal sector or petty commodity production: dualism or dependence in urban development? 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trabajadores por la ciudad: aporte de las mujeres a la gestió n ambiental de los residuos só lidos en amé rica latina the case for universal basic services unpacking the urban infrastructure nexus with environment, health, livability, well-being, and equity inequality and sustainability inequality, cooperation, and environmental sustainability cuarta declaració n de la selva lacandona (the revolutionary clandestine committee) within and beyond the pandemic. demanding a care income and a feminist green new deal for europe. undisciplined environments (undisciplined environments collaborative feminist degrowth: pandemic as an opening for a care-full radical transformation (degrwoth) from pandemic toward care-full degrowth trajectories of the earth system in the anthropocene the authors thank the two anonymous reviewers, as well as john stehlin and lani marina tsinnajinnie for their feedback on the ideas presented in this perspective piece. we also owe a debt of gratitude to the informal workers, grassroots communities, and frontline organizations who have shared their time and insights with us, in both paraguay and india. key: cord- -ucwuptgg authors: fang, h.; wang, l.; yang, y. title: human mobility restrictions and the spread of the novel coronavirus ( -ncov) in china date: - - journal: nan doi: . / . . . sha: doc_id: cord_uid: ucwuptgg we quantify the causal impact of human mobility restrictions, particularly the lockdown of the city of wuhan on january , , on the containment and delay of the spread of the novel coronavirus ( -ncov). we employ a set of difference-in-differences (did) estimations to disentangle the lockdown effect on human mobility reductions from other confounding effects including panic effect, virus effect, and the spring festival effect. we find that the lockdown of wuhan reduced inflow into wuhan by . %, outflows from wuhan by . %, and within-wuhan movements by . %. we also estimate the dynamic effects of up to lagged population inflows from wuhan and other hubei cities, the epicenter of the -ncov outbreak, on the destination cities' new infection cases. we find, using simulations with these estimates, that the lockdown of the city of wuhan on january , contributed significantly to reducing the total infection cases outside of wuhan, even with the social distancing measures later imposed by other cities. we find that the covid- cases would be . % higher in the chinese cities outside hubei province, and . % higher in the non-wuhan cities inside hubei, in the counterfactual world in which the city of wuhan were not locked down from january , . we also find that there were substantial undocumented infection cases in the early days of the -ncov outbreak in wuhan and other cities of hubei province, but over time, the gap between the officially reported cases and our estimated "actual" cases narrows significantly. we also find evidence that enhanced social distancing policies in the chinese cities outside hubei province are effective in reducing the impact of population inflows from the epicenter cities in hubei province on the spread of -ncov virus in the destination cities elsewhere. human mobility contributes to the transmission of infectious diseases that pose serious threats to global health. indeed, in response to pandemic threats many countries consider and impose measures that restrict human mobility flows as one of their response plans (bajardi et al., ; wang and taylor, ; charu et al., ) . however, restrictions on human mobility are controversial not only because of their negative economic impacts, but also because of the uncertainty about their effectiveness in controlling the epidemic. even if restricting human movement could lead to improvements in disease control and reductions in health risks, it is empirically challenging to quantify the impact of human mobility on the spread of infectious diseases, and to understand the detailed spatial patterns of how the infectious disease spreads. both granular disease occurrence data and human mobility data (charu et al., ) are hard to obtain; moreover, it is difficult to disentangle the impact of human mobility from other potential contributing factors in the spread of epidemics hollingsworth et al., ) . in this paper, we exploit the exogenous variations in human mobility created by lockdowns of chinese cities during the outbreak of the novel coronavirus ( -ncov), and utilize a variety of high-quality data sets, to study the effectiveness of an unprecedented cordon sanitaire of the epicenter of covid- , and provide a comprehensive analysis on the role of human mobility restrictions in the delaying and the halting of the spread of the covid- pandemic. the fast-moving -ncov that infected , people and claimed , lives as of march , is deteriorating into one of the worst global pandemics. the virus emerged in the city of wuhan in the hubei province of china in early december of , spread mainly through person-to-person contact (chan et al., ) , and rapidly reached more than countries as of march , . currently, there are no licensed vaccines or specific therapeutics to combat covid- . the lockdown of million people in wuhan from january , represents by then the largest quarantine in public health history, and offers us an opportunity to rigorously examine the effects of the city lockdown and understand the relationship between human mobility and virus transmission. specifically, this paper studies five research questions. first, how does the lockdown of the city of wuhan amid the novel coronavirus outbreak affect population movement? second, how do population flows among chinese cities, particularly outflows from wuhan and other cities in hubei province, affect virus infection in the destination cities? third, is there evidence of, and if so, what is the magnitude of, undocumented cases of covid- cases in wuhan and other cities in hubei province during the early stages of the epidemic? and how does the extent of undocumented infection cases evolve over time? fourth, how many covid- cases elsewhere in china were prevented by the unprecedented wuhan lockdown? fifth, are social distancing policies in destination cities effective in reducing the spread of the infections? we utilize reliable datasets on population migration among pairs of chinese cities and the within-city population movements of each city at the daily level from baidu migration, and the city-level daily numbers of confirmed covid- cases, recovered patients, and death tolls from the chinese center for disease control and prevention (ccdc) during a sample period of january -february , , covering days before and days after the city lockdown on january , , as well as the matched data from the same lunar calendar period in . we first employ various difference-in-differences (did) estimation strategies to disentangle the effect of wuhan lockdown on human mobility reductions from other confounding effects including panic effect, virus effect, and the spring festival effect-the spring festival of the chinese new year is on january , (table ) . we find that the lockdown of wuhan reduced inflow into wuhan by . %, outflows from wuhan by . %, and within-wuhan movements by . %. we also estimate the dynamic effects of up to lagged population inflows from wuhan and other hubei cities, the epicenter of the -ncov outbreak, on the destination cities' new infection cases ( figure ). we discover that the estimated effects of the different lags of inflows from wuhan and hubei both show a clear inverted u -shape with respect to the lags, with the largest impact on the newly confirm cases today comes from the inflow population from wuhan or other cities in hubei about to days earlier. we find, using simulations with these estimates, that the lockdown of the city of wuhan on january , contributed significantly to reducing the total infection cases outside of wuhan, even with the social distancing measures later imposed by other cities. we find that the covid- cases would be . % higher in the chinese cities outside hubei province, and . % higher in non-wuhan cities inside hubei, in the counterfactual world in which the city of wuhan were not locked down from january , . we also find that there were substantial undocumented infection cases in the early days of the -ncov outbreak in wuhan and other cities of hubei province, but over time, the gap between the officially reported cases and our estimated "actual" cases narrows significantly. we also find evidence that imposing enhanced social distancing policies in the chinese cities outside hubei province is effective in reducing the impact of population inflows from the epicenter cities in hubei province on the spread of -ncov virus in the destination cities elsewhere. by providing a rigorous estimation of the impact of within and cross-city migration on the spread of the -ncov virus in china, our study contributes to fast-growing literature on -ncov infection, mostly in the medical and public health fields. huang et al. ( ) describe high rates of respiratory distress, intensive care admission, and abnormal findings on chest computed tomography (ct) in the first patients hospitalized from december to january in wuhan, as well as a % death rate. chan et al. ( ) investigate a family cluster and confirm the human-to-human transmission of this novel coronavirus within hospitals and families. the basic reproduction number (r ) for covid- in studies has a mean of . and a median of . (liu et al., ) (compared to for sars (wto, ) ). this study is also related to disaster-induced migration, which has often occurred during flooding (gray and mueller, ) , drought (munshi, ) , earthquake (lu et al., ) , and other destructive climatic phenomena. given that the -ncov has rapidly spread worldwide due to human travel and caused severe illness and significant mortality, it is therefore essential to understand the impact of various control measures on human mobility and the virus transmission. qiu et al. ( ) apply machine learning tools and use exogenous temperature, wind speed, and precipitation in the preceding third and fourth weeks as the instruments to show that the massive lockdown and other control measures significantly reduced the virus transmission. their results highlight that the population outflow from the outbreak source city poses higher risks to the destination cities than other social and economic factors, such as geographic proximity and similarity in economic conditions. our results are also in line with the results of the latest modeling exercises, which mostly rely on model calibrations of various parameters, such as generation time, incubation period, detection rates, and changes in travel flow. using the global epidemic and mobility model, chinazzi et al. ( ) project the impact of travel limitation on the national and international spread of the -ncov. the study finds that only . % of infected cases were reported as of february , and the wuhan lockdown reduced the cases by % in cities outside wuhan by january . the study most closely related to ours is li et al. ( ) , which shows that contagious but undocumented covid- cases facilitated the geographic spread of the epidemic in china. using a networked dynamic meta-population model and bayesian inference, li et al. ( ) find that % of all infections were undocumented before the wuhan lockdown and reported infections would have been reduce by . % in china, without transmission from undocumented cases between january and january . lai et al. ( ) build a travel network-based susceptibleexposed-infectious-removed (seir) model to simulate the outbreak across cities in mainland china. they use epidemiological parameters estimated from the early stage of outbreak in wuhan to parameterize the transmission before the non-pharmaceutical interventions (npi) were implemented. the npis they consider include travel bans and restrictions, contact reductions and social distancing, early case identification and isolation. through their sim-ulations, they find that the npis deployed in china appear to be effectively containing the covid- outbreak, but the efficacy of the different interventions varied, with the early case detection and contact reduction being the most effective. moreover, deploying the npis early is also important to prevent further spread. relative to our study, it is important to point out that in their simulations, they assumed that the pattern of population movements was the same in years when there were no outbreaks and interventions. to the best of our knowledge, this paper is the first to provide a causal interpretation of the impact of city lockdown on human mobility and the spread of -ncov, and to clearly disentangle the lockdown effects from other potential contributing factors such as panic and virus effect, as well as the seasonal spring festival effect (see section ). the remainder of the paper is structured as follows. in section , we describe the data sets used in our analysis. in section , we present different difference-in-difference estimation strategies to separate the lockdown effect, panic effect, virus (deterrence) effect, and the spring festival effect on population movements in china. in section , we estimate the distributed lag effects of inflows from the epicenter cities of the -ncov outbreak on destination cities' daily infection cases. in section , we study how the enhanced social distancing policies, or "lockdown" policies, in the destination cities' impact the effects of the population inflows from the epicenter cities. in section , we conclude. population migration data. we obtain inter-city population migration data from baidu migration, a travel map offered by the largest chinese search engine, baidu. . the baidu migration data set covers , pairs of cities per day for chinese cities between january and march in , and between january and february in . note that, by the lunar calendar, the data covers the same period of days before and days after the spring festivals, respectively for year and year . the daily inter-city migration data consist of , , city-pair observations each year. in addition, baidu provides the daily within-city mobility data for each city in the sample period, which is a panel consisting of , city-day level observations each year. the baidu migration data is based on real-time location records for every smart phone using the company's mapping app, and thus can precisely reflect the population movements between cities. for each of the cities, baidu migration provides the following informa- tion: ( ). the top origination cities (oc) for the population moving into the city and the corresponding percentages of inflow population that originated from each of the top oc; ( ). the top destination cities (dc) for the population moving out of the city, and the corresponding percentages of the outflow population that go into each of the top dc. in the data, the cumulative percentages of the inflow population from the top origination city, and the cumulative percentages of the outflow population into the top destination cities, reach % per city on average. this ensures that the baidu migration data capture near complete inflows and outflows for each of the cities in the data. in addition, the baidu migration data provides three migration intensity indicators: the daily in-migration index (imi) of a city, the daily out-migration index (omi) of a city, and the daily within-city migration index (wcmi). the intensity indicators are consistent across cities and across time. to convert the index to the number of people, we use the actual number of inflow population into shanghai by airplanes, trains and buses/cars, and the number of within-shanghai trips using subways, buses and expressways, collected by the national earth system science data center for the period of february to february , . using this data, we estimate that one index unit in the imi and omi corresponds to , person movements, and one index unit in wcmi corresponds to , , person movements. we are thus able to calculate the number of daily inflow and outflow migrants in each city-pair, as well as the number of within-city population movements. table presents the summary statistics of the population flows at the city-pair-day level and city-day level. it shows drastic declines in the average inflows, average outflows, and average within-city migration in , compared to a sample period in (matched by the lunar calendar date). the plummeting of the migration statistics due to the wuhan lockdown is also depicted in figure . the three figures on the top show the inflows into wuhan, outflows from wuhan and within-wuhan flows, for year (solid line) and year (dashed line), matched by the lunar calendar; and the bottom shows the corresponding figures for the national city averages. the first vertical line indicates the date of january , when experts confirmed that -ncov could transmit from human to human; and the second vertical line indicates the date of january , when wuhan was locked down. it is clear that while the flows in tracked that of well until january , the level dropped to a fraction of their corresponding levels, particularly after the lockdown of wuhan. [ table about here] [ figure about here] it is important to emphasize here that the mobility data is about the movement of people from one city to another based on geo-location services of the smartphones; as such a person flowing out of city a to city b is not necessarily a resident of city a, but he/she must have been to city a before moving to city b. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . outbreak data. covid- daily case counts are collected from china cdc, which provides daily updates on confirmed, dead, and recovered covid- cases in each city. from january to february , , the data covers , laboratory-confirmed covid- cases, , death cases, and , recovered cases in cities in china. panel b of table presents the summary statistics of covid- data, and figure plots the trends of daily statistics of covid- separately for the epicenter city of wuhan, for other cities in hubei province, and for cities outside of hubei. there are many possible reasons for us to treat the officially reported numbers of confirmed cases in wuhan and other cities of hubei with more caution, and to treat them differently from the data of cities outside of hubei. as the epicenter of covid- , the health care systems in wuhan and other cities in hubei were overwhelmed by the sheer number of patients who needed laboratory testing, especially in the early phases of the virus outbreak. as such, the over-extended medical system in wuhan and other cities in hubei might have caused delays in the testing of the patients who contracted covid- ; and because of the delay, some patients who contracted covid- might have self-recovered, or might have died, before being officially tested; and some who were infected with the virus might be asymptomatic. there is also a possibility that government officials in the epicenter cities had incentives to downplay the severity of the outbreak, at least initially. these considerations impact how we use the outbreak data in section . the incubation period of -ncov is long in comparison with sars; moreover, the virus can transmit while the person is still asymptomatic, which increases the probability a person with the novel coronavirus will travel and unknowingly spread the virus to others. to suppress the spread of -ncov, the central government of china imposed an unprecedented lockdown in wuhan starting from am of january , , and in other hubei cities several days later. as of february , , cities in provinces issued different source: http:// ncov.chinacdc.cn/ -ncov/ the spike of confirmed cases observed on february in hubei province is. for the most part, the result of a change in diagnosis classification for which , clinically (rather than laboratory) confirmed cases were all reported as new cases on february , , even though they might have been clinically diagnosed in the preceding weeks. also on february , , a new communist party secretary of hubei province was appointed who started his position on the next day. the range of the incubation period for -ncov is estimated to be - days, or even as long as days. the median incubation period is about days, see lauer et al. ( ) . in contrast, the incubation period for sars is - days. in addition, sars transmits only after showing symptoms. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . levels of lockdown policies. table a in the appendix provides the detailed information about the various forms of population mobility control in different cities. we also plot the geographic distributions of sample cities and cases in figure . [ figure about here] there are several confounding factors in our attempt to causally quantify the impact of lockdown on human mobility, and on the spread of infectious viruses. first, the virus outbreak happens right before the spring festival of the chinese lunar new year, which causes the largest annual human migration every year. second, the virus itself, even in the absence of a mandatory lockdown, may lead to curtailed human movement as people attempt to avoid exposure to the virus in the journeys and public spaces. we refer to this deterrence effect as the virus effect. third, for the city of wuhan and other cities in hubei that are close to wuhan, there is also the possibility of a panic effect, in reaction to the virus. the panic effect can lead to an increase in the population outflow from the epicenter of the virus outbreak, and a decrease of the population inflow to the epicenter, particularly the city of wuhan. the panic effect is likely to peak when the government officially confirmed on january , that the novel coronavirus can transmit from person-to-person. in our analysis below, we create a specific pre-lockdown period before ,t , which includes the threeday period between january and january , , to capture the panic effects. note that while the virus effect applies to movement into and out of all cities, the panic effect is more specific to the cities in the epicenter, especially wuhan, and can have a positive effect on outflows, and a negative effect on inflows. within hours of the wuhan lockdown, travel restrictions were imposed on the nearby cities of huanggang and ezhou, and were eventually imposed on all other cities in hubei, affecting a total of about million people. on february , the city of wenzhou implemented a partial lockdown in which only one person per household was allowed to exit once every two days, and most of the highway exits were closed. following wenzhou, another six cities, hangzhou, zhumadian, ningbo, haerbin, fuzhou, and zhengzhou also launched similar partial lockdowns on february . in another cities, surveillance and tighter controls applied to each neighborhood. in the provinces of liaoning and jiangxi, as well as major cities such as shenzhen, guangzhou, nanjing, ningbo, chengdu and suzhou, checkpoints have been set up to control the inflow population. the migration across china, which officially begins from about two weeks before, and ends about three weeks after, the lunar new year is often referred to as chunyun (meaning spring movement). in , approximately billions trips were made during chunyun, see https://www.cnn.com/travel/article/ lunar-new-year-travel-rush- /index.html. the large outflow from wuhan is possible because many people in wuhan are migrant workers and college students with hometowns elsewhere. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . we first examine the impact of city lockdown on inter-city population mobility, including inflow and outflow, between a city pair (i, j). to disentangle the contributions of these confounding factors on human mobility, we exploit many unique sources of variations in the data, and employ several did estimation strategies by comparing different treatment and control groups. the did specification can be described as follows: where i, j, and t respectively index the destination city, origination city, and date; the dependent variable, ln(flow i,j,t ), is the logarithmic population flows received by city i from city j at date t. the definition of treat varies by specific did designs, and we will be explicit about its definition below. the city-pair fixed effect µ i,j is included to absorb the city-specific and the city-pair specific heterogeneities that may contaminate the estimation of our interested coefficient β . we also control for the date-fixed effect θ t to eliminate the time-specific impact, including the spring festival travel effect. the standard errors are clustered at the daily level. in equation ( ), we include two pre-lockdown period indicators: before ,t is a dummy that takes value for the period from january to january , ( to days before the wuhan lockdown), which can be used to examine the parallel trend assumption in the did analysis; before ,t is a dummy that takes value for the period from january to january , , three days before the unprecedented wuhan lockdown, but after the official announcement that the novel coronavirus can spread from person to person. before ,t allows us to capture the panic effect. finally, after t is a dummy that takes value for the sample period after the wuhan lockdown, between january and february , . the omitted benchmark period is from january to january , . on january , , an expert at china cdc confirmed that the novel coronavirus can spread from human to human. the confirmation highlighted the increasing risk of an epidemic. prior to the january announcement, the experts' assessment of the virus was that it was "preventable and controllable," and "at this time, there is no evidence of person to person transmission." . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . we also estimate the effect of lockdown on the within-city population movement utilizing the city-level data and a variety of did specifications: where i and t index the city and date. ln(withincityflow i,t ) is the logarithmic within-city population mobility measure for city i at date t. similar to equation ( ), treat will be defined according to the did design. before ,t , before ,t and after t are defined in the same way as in equation ( ). we include the city fixed effects µ i and date fixed effects θ t . the standard errors are clustered at the daily level. [ table about here] in table , we report the results from three sets of regressions specified according to equation ( ) for inter-city inflows (panel a) and outflows (panel b), and according to equation ( ) for within-city movement (panel c). we implement three models that differ in the estimation sample, and the definition of the variable treat. model : wuhan vs. unlocked cities in . the estimation sample used in the regressions reported in column ( ) is the data for wuhan and cities that were never locked down during the coronavirus outbreak. in panel a when we examine the inflow population, treat takes value if the destination city i is wuhan; in panel b when we examine the outflow population, treat takes value if the origination city j is wuhan. the control group consists of cities that are not subject to any mobility restrictions. in panel c when we examine the within-city mobility, treat takes value if city i is wuhan. we interpret the coefficient estimate of treat * before ,t as measuring the panic effect of wuhan relative to the unlocked cities; and the coefficient estimate of treat * after t as measuring the lockdown effect. the coefficient estimate of treat * before ,t allows us to examine whether the parallel trend assumption for did is recall that baidu migration data covers chinese cities, cities implemented some level of mobility restrictions (see table a ). if the virus effect is stronger in wuhan than in the unlocked control cities, then the coefficient estimate of treat * after t also includes the excess virus effect on the population in wuhan over the average virus effect experienced by the population in the control cities. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . satisfied. it is important to note that the possibly time-varying spring festival effects and the virus effects are both absorbed in the day fixed effects. based on the coefficient estimate of the term treat * after t , we find that wuhan's lockdown reduces the inflow population to wuhan by . % (= − exp(− . )), the outflow population from wuhan by . % (= − exp(− . )), and within-city population movements in wuhan by . %(= − exp(− . )), relative to all other unlocked cities in the post-lockdown period in . in panel c, we also find that the coefficient of treat * before ,t is significantly negative at - . , suggesting that the official confirmation of the person-toperson transmission reduces the within-city movement in wuhan by . % from jan to jan in . this points to a panic effect for the within-city population flow in wuhan, but we do not observe a significant panic effect for inter-city flows in and out of wuhan in model . model : wuhan vs. wuhan . model could be criticized on the ground that wuhan may not be comparable to the unlocked cities -after all, these cities that never imposed any mobility restrictions in the covid- outbreak could be very different from wuhan. in model , we compare the population movements of wuhan in to itself in the same matched lunar calendar period in , during which wuhan is free of lockdown and coronavirus outbreak. thus, the estimation sample in model is the daily inflows into and outflows out of wuhan, as well as the daily within-city movements in wuhan for years and . under model , in panel a when we examine the inflow population, treat takes value if the destination city i is wuhan and year is ; in panel b when we examine the outflow population, treat takes value if the origination city j is wuhan and the year is . the control group is wuhan . in panel c when we examine the within-city mobility, treat takes value if the year is . under model , the coefficient estimate of treat * before ,t measures the panic effect related to the virus outbreak in wuhan; and the estimate of treat * after t measures the sum of the lockdown effect and the virus effect. the coefficient estimate of treat * before ,t still allows us to examine whether the parallel trend assumption for did is satisfied. the day fixed effects absorb the possibly time-varying spring festival effects. notice that the interpretation of the coefficient estimate of the term treat * after t differs from that in model because of the differences in the treatment and control groups. under model , the estimated coefficients on treat * after t , which, as we explained above, capture both the lockdown and the virus effects, remain negative, and economically and statistically significant in all panels. the estimates suggest that the lockdown of wuhan, together with the deterrence effect of the virus (the virus effect), on average reduces the . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . inflow population into, outflow population from, and within-city movements in wuhan by . % (= − exp(− . )), . % (= − exp(− . )), and . % (= − exp(− . )), respectively, relative to the same lunar calendar days in . we also find that the coefficient on treat * before ,t is significantly positive in panel b and significantly negative in panel c, suggesting that the official confirmation of person-to-person spread of covid- creates a panic effect, causing an increase of outflow from wuhan of . % (= exp( . ) − ), and a decrease of within-city movements in wuhan of . % (= − exp(− . )), during the three days after the announcement but before the city lockdown. however, we do not observe a statistically significant panic effect for the population inflow into wuhan, suggesting that people in other cities were not yet sufficiently concerned about the virus outbreak in wuhan and did not avoid traveling to wuhan, even after the official confirmation of the personto-person transmission. finally, we should also point out that the coefficient estimates for treat * before ,t are all statistically insignificant, which suggests that the parallel trend assumption for the dids are plausible. model : wuhan vs. seven other lockdown cities . in model , the coefficient estimates of treat * after t provide us with an estimate of the sum of the lockdown and the virus effects. in order to isolate the lockdown effect from the virus effect, we consider model , where the estimation sample consists of data of the city of wuhan and seven other cities that went into partial lockdown on february and february , , to days after the lockdown of wuhan, in an effort to curtail the spread of the virus. as we show in table a in the appendix, these seven cities are more comparable to wuhan than other unlocked cities in terms of the epidemic situation and other economic indicators, and thus provide a reasonable control group to partial out the virus effect. in particular, it is much more plausible than in model (where the control cities are cities that were never locked down) to assume that the deterrence effect of the virus on human mobility in the seven cities is similar to that in wuhan. the estimation sample for model consists of data from wuhan and the seven cities for the period between january and february , . note that during this period, none of the seven control cities were locked down yet, even though they were soon eventually locked down. the definition for treat variables are as follows. in panel a, treat takes value if the destination city i is wuhan; in panel b, treat takes value if the origination city j is wuhan; in panel c, treat takes value if city i is wuhan. the control group consists of the these seven cities are: wenzhou, which was partially lockdown from february , ; and ningbo, zhumadian, hangzhou, zhengzhou, haerbin, and fuzhou, which were partially locked down on february , . as summarized in table a in the appendix, partial lockdown includes "closed-off management" on highways, railways and public transport systems; and sets up checkpoints to control the inflow population, and implements surveillance and tighter controls in each neighborhood. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . seven cities. under model , the coefficient estimate of treat * before ,t measures the panic effect related to the virus outbreak in wuhan relative to the seven control cities; and the estimate of treat * after t measures the lockdown effect only. the coefficient estimate of treat * before ,t still allows us to examine whether the parallel trend assumption for did is satisfied. the possibly time-varying spring festival effects and the virus effects are both absorbed in the day fixed effects. we find that the wuhan lockdown significantly reduces the inflow into, outflow from, and within-city movements in wuhan by . % (= − exp(− . )), . % (= − exp(− . )), and . % (= − exp(− . )), respectively. we interpret these as the pure lockdown effect on population mobility related to wuhan. summary. based on our preferred estimation models, which are models and , table summarizes our estimates of the panic effect, the virus effect, and the lockdown effect on inflows into, outflows from wuhan, and within-city population movements in wuhan. [ table about here] in table , the lockdown effects are directly calculated from the corresponding coefficient estimates of treat * after from model discussed above; the panic effects are from the coefficient estimates of treat * before in model . for the virus effect, we recognize that the coefficient estimates of treat * after in model incorporate both the lockdown and the virus effects. thus we calculate the virus effect on inflows into wuhan to be exp(− . − (− . )) − = − . %, on the outflows from wuhan to be exp(− . − (− . )) − = − . %, and on the within-city flow in wuhan to be exp(− . −(− . ))− = − . %. because our models assume that the different effects enter exponentially in explaining the flows -recall the natural log specifications in equations ( ) and ( -when we would like to calculate the impact of two or more effects on the population flows, we should not simply add the individual effects. for example, the joint impact of the panic and virus effects on outflows out of wuhan is ( + . %) * ( − . %) − = . %, instead of the simple sum of . % − . % = . %. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . we now examine the impact of human mobility on the transmission of -ncov. considering that almost all the new covid- cases outside the city of wuhan were confirmed after the wuhan lockdown while almost all inter-city population flows occurred prior to the wuhan lockdown (see figures and ) , we investigate the imported infections by specifically looking at the impact of population inflows from cities in the epicenter of the novel coronavirus outbreak, namely, wuhan and other cities in hubei province, on the new cases in the destination cities. recognizing that -ncov has a long incubation period, we estimate a dynamic distributed lag regression model taking into account that inflows from wuhan with different lags may have differential impacts on the current new cases in the destination cities. most of the medical literature states that the -ncov virus has a median incubation period of five days, and some can have an incubation period of days or more (see lauer et al. ( ) , e.g.). luckily, our data allows us to incorporate the possibility that contact with an infected person from wuhan or other cities in hubei can result in confirmed infections in the destination city for up to days. the analysis focuses on the daily new confirmed covid- cases in the post-wuhan lockdown period from january to february , , for cities i that are outside of hubei province. specifically, we run the following regression: where i indexes the cities outside of hubei, and t ∈ { , ..., } indicate the date. κ ∈ { , ..., } indicates the time lapsed from the inflows from wuhan or other hubei cities till the current date t. ln( +newcase i,t ) is the logarithm of the number of new confirmed cases in city i at date t. inflow i,wh,t−κ and j =i,j =wh,j∈hb inflow i,j,t−κ are the inflows from wuhan, and the inflows from the other cities in hubei to city i, respectively, κ days prior our log-log specification is based on the classical susceptible-infectious-removed (sir) model in epidemiology. date t = indicates the date of january , , and t = the date of february , . . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . to the focal date t. we control for destination city fixed effects µ i and date fixed effects θ t . note that, in this regression we include only cities outside of hubei province for two reasons. first, wuhan and other cities in hubei province are the epicenter of the novel coronavirus outbreak, and we are interested in how population outflows from these cities to other cities outside hubei affect the destination cities' covid- cases. second, the confirmed covid- cases in wuhan and other cities in hubei province are likely to be inaccurate for the following reasons. first, as widely reported, the health care systems in wuhan and other cities in hubei were totally overwhelmed by the sheer number of covid- patients. this made it impossible to conduct laboratory tests on all patients, which can lead to delayed confirmation of infected patients. second, during the delay some of the infected may have healed on their own, or have died before being confirmed. third, local government officials may face strong incentives to under-report the number of infected cases. in section . , we will evaluate the possible downward biases of the officially reported cases in wuhan and other cities in hubei based on our estimates. in contrast, the confirmed cases in other cities are likely to be accurate, as their numbers are not large enough to overwhelm their local health care system; and the incentives to under-report are much weaker in cities outside of hubei. the estimated coefficients β κ and β κ in equation ( ) respectively represent the impact of the inflows from wuhan and other cities in hubei κ ∈ { , ..., } days ago on the destination cities' new cases today. they are respectively plotted in the top and bottom panels of figure . we also fit a spline smoothed curve of the estimated effects of the different lags of inflows from wuhan and hubei, which both show a clear inverted u -shape with respect to the lags. interestingly, both graphs show that the largest impact on the newly confirm cases today in chinese cities outside hubei comes from the inflow population from wuhan or other cities in hubei about to days ago. the pattern exhibited in figure is consistent with the hypothesis that the incubation period of the -ncov is up to to days, but also consistent with a shorter incubation period coupled with secondary infections. [ figure about here] anecdotal evidence suggests the official statistics of covid- cases in wuhan may have been under-reported due to the shortages of testing equipment and other medical resources. with the estimated dynamic effects as shown in figure , which is estimated under the plausible assumption that the reported cases outside hubei province are reliable, we can estimate the "actual"' number of infection cases in wuhan and other cities in hubei. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . to estimate the "actual" number of infection cases in wuhan using the estimated equation ( ), we technically need to impute a value for inflow wh,wh,t−κ , that is "inflows from wuhan to wuhan." we proxy these inflows by the daily within-wuhan population movement from january to february , i.e., by withincityflow wh,t−κ . similarly, to estimate the "actual" number of infection cases in other cities in hubei, we need to replace the inflow from city j to itself by the corresponding daily within-city-j population movements. we need to make an additional assumption about the city fixed effects. recall that cities in hubei province were not included in the estimation sample for equation ( ), as such there are no city fixed effects estimated for cities in hubei. luckily, it is plausible to assume that the city fixed effects in hubei is the average of the city fixed effects of all chinese cities outside hubei. according to world bank's (respectively, imf's) method of estimating per capita gdp, hubei's per capita gdp in was usd , (respectively, usd , ), and the average per capita gdp of mainland china was usd , (respectively, usd , ). hubei is not only geographically and demographically in the center of mainland china, it is also economically the average of china. thus we believe it is defensible to proxy the fixed effects of hubei cities by the average of the city fixed effects outside of hubei. [ figure about here] in figure , we plot the estimated daily new cases according to the above-described method using the estimated equation ( ), as well as the corresponding cumulative cases for wuhan (panel a) and other cities of hubei (panel b) for the period of january to february , . we also plotted the corresponding daily and cumulative officially reported (i.e., documented) cases. we find a persistent gap between the estimated and reported laboratory-confirmed cases in wuhan before february , , just before the announcement of a new party secretary for hubei province on february , . the estimated "actual" number of infection cases is . times the reported cases during the first days after the wuhan lockdown, on average. in particularly, we estimate that on january , , the day of the wuhan lockdown, . % of our estimated infections in wuhan were undocumented in the sense that the number of officially reported cases on that day was only . % of our estimated infection cases. this gap widened over time, possibly as a result of the overwhelmed health care system, and peaked at . % on january . the proportion of undocumented infections started to decline gradually afterward, when more medical support and resources were mobilized across china to support wuhan. as of february , we estimate that there were , total covid- infections in wuhan, which is . % higher than the official reported statistics for wuhan -a total of , cases. the . % discrepancy can be plausibly be explained by the unaccounted for self-healing and death that might have occurred during the early periods of the outbreak between january and early february. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . thus, we are led to conclude that the almost all infection cases in wuhan were able to be treated over time as the stress on the health system was relieved, and moreover, the official statistics were mostly accurate, as can be seen from the left figure on the daily new cases in panel a in figure . it is useful to note that the general pattern of the undocumented covid- infections in wuhan before and after the lockdown based on our estimates is consistent with that reported in li et al. ( ) . they use a networked dynamic meta-population model and bayesian inference to estimate the proportion of undocumented infections in the epicenter of the outbreak, as well as the respective inflection rates for documented and undocumented cases. they estimate that % of all infection cases as of january , were undocumented. our interpretation of these undocumented cases is broader than the asymptomatic cases (i.e. covid- cases that do not show symptoms); we believe that some of the undocumented cases were due to the lack of ability to test the rapidly increasing infection cases in the early period of the outbreak. most of the undocumented cases become documented over time as the care capacity was strengthened in wuhan. in the bottom panel of figure , we plot our estimated daily new confirmed cases and total infection case for cities (other than wuhan) in hubei province, together with the officially reported series. we find that in the cities, infections were more seriously underreported in the first week after the wuhan lockdown when our estimated infected cases are . times of the reported cases. our estimate reveals a very high rate of undocumented infections on the first day of wuhan lockdown: . %. the gap narrowed gradually with more medical resources provided and more stringent control measures implemented in those cities. by the end of our study period on february , , the estimated "actual" number of infections is , cases in other cities in hubei, which is . % higher than the officially reported cumulative cases ( , ) . again, the discrepancy between the estimated and officially reported cumulative cases can at least be partially attributed to the unaccounted for self-healing and death that might have occurred during the early periods of the outbreak. locking down wuhan, a city of million residents, was an unprecedented measure to contain the spread of the novel coronavirus. an important policy-relevant question is, then, how many covid- cases were actually prevented by the wuhan lockdown in china? to answer this question, we must estimate the counterfactual number of covid- cases that would have occurred in other cities in the absence of wuhan lockdown, which would, in turn, . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . require a counterfactual estimate of the outflows from wuhan to other chinese cities, had there been no lockdown of wuhan. in section , we provided the estimates of how panic effect and virus effect will separately affect the outflows from wuhan to other cities in china, separate from the lockdown effect. these effects are summarized in table . it suggests that, in the absence of the wuhan lockdown, the virus effect and panic effects would have led to a . % decrease and a . % increase in the outflow population from wuhan, respectively. based on these effects, therefore, in the absence of wuhan lockdown, we would expect that the outflows from wuhan in days after january -the date of wuhan lockdown -to be ( − . ) * ( + . ) = . ( ) times higher than the normal outflows from wuhan to other cities. we use the daily level of outflows from wuhan to a city in on the same lunar calendar day as a measure of the normal outflow, and multiple the number by . to obtain the daily counterfactual inflows from wuhan to the city, had there been no lockdown of wuhan from january , . using this estimation method, we find that on average, the estimated counterfactual outflows from wuhan to other cities in hubei between january and february , would be , , , a level that is . times the actually observed inflow population observed in the data in (with the lockdown), which is , , ; similarly, the average inflows from wuhan to the other cities outside hubei in china would be , , , . times the actual inflow population to those cities during the same period in , which is , . we denote the counterfactual inflows from j = wuhan into city i at date s ∈ { , ..., } from the above calculation as inflow i,wh,s . we assume that the wuhan lockdown did not impact the population movements within other cities, and population flows among other cities. we also assume that all the control measures implemented by other cities after the wuhan lockdown remain in place. thus the parameter estimates of the dynamic lag effects of inflows from wuhan and other cities in hubei, estimated in equation ( ), remain valid as an epidemiological diffusion equation that is not affected by human mobility restrictions that result from the wuhan lockdown; the lockdown only affected the human flows. with these considerations in mind, we simulate the counterfactual number of covid- cases, had there been no wuhan lockdown, on date t ∈ { , ..., } (i.e., from january to recall that outflows from wuhan are not just residents of wuhan; any travelers who entered wuhan for whatever reason and then leave wuhan would be included in the wuhan outflows measured by baidu migration data. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . february , ) in cities i outside hubei province by the following equation: inflow i,j,t−κ +μ i ( ) whereβ κ andβ κ are coefficient estimates obtained from regressions specified in equation ( ) and reported in figure , and andμ i are the estimated city fixed effects from the same regression. note that in predicting the counterfactual covid- cases without wuhan lockdown, we use the counterfactual inflows from wuhan to city i for days after january inflow i,wh,s discussed previously. we are also interested in predicting the counterfactual cases in other non-wuhan cities in hubei province using the same method as that described above, with two differences. first, since hubei cities are not included in the estimation of equation ( ), we do not have the city fixed effects for the hubei cities. as we argued in section . , it is plausible to assume that the fixed effects of hubei cities are the average of city fixed effects of the cities outside hubei. we maintain this assumption as well in this counterfactual exercise. second, following the same strategy of section . , for a non-wuhan city j in hubei province, we use the within-city-j population movement at date t to proxy for the inflow to city j from city j when we implement equation ( ) for non-wuhan hubei cities. in figure , we present the counterfactual estimates of covid- cases had there been no wuhan lockdown (in solid curve), and the officially reported cases (in dashed curve) for cities outside hubei province (panel a) and non-wuhan cities of hubei (panel b). the left figure in each panel depicts the model's counterfactual prediction and the actual of daily infection cases, and the right figure depicts the evolution of cumulative cases from january to february , . the gap between the estimated counterfactual number of infection cases (the solid curve) and the officially reported cases (the dashed curve) on the right figure represent the number of covid- cases prevented by the wuhan lockdown. as of february , , the officially reported number of covid- in the cities outside hubei province was , , but our counterfactual simulation suggests that there would have been , cases, had there been no wuhan lockdown. similarly, the officially reported number of covid- cases in the non-wuhan cities in hubei was , by february , , but our counterfactual simulation suggests that the number of infection cases would have been , , had there been no wuhan lockdown. that is, the covid- cases would be . % higher in cities outside hubei, and . % higher in other cities in hubei as of february , in the counterfactual world in which the city of wuhan were not locked down from january , . our findings thus suggest that the lockdown of the city of wuhan from january . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . , played a crucial role in reducing the imported infections in other chinese cities and halts the spread of -ncov virus. our model also allows us to project when the new infection cases would have peaked in other cities in the absence of wuhan lockdown. as shown by the solid curves in the left figures of each panel, our model projects that in the absence of wuhan lockdown, the new daily infection cases in the non-wuhan cities in hubei would have peaked on february , the th day after the lockdown of wuhan, at a level of , daily new cases; and elsewhere in china, it would have peaked on february , , the th day after the lockdown of wuhan, at a level of , daily new cases. we also find that the estimated daily new cases in the counterfactual world gradually converge to the reported daily cases from february , suggesting that the social distancing measures implemented elsewhere in china would have worked eventually to contain the spread of -ncov virus, even if the city of wuhan was not locked down on january , but the initial onslaught on the medical system in all cities in china would have been much more severe, and the total number of infection cases elsewhere would have been significantly higher. [ figure about here] as the -ncov virus spread throughout the world, many countries are also implementing lockdown measures, and mandate social distancing as a policy response to contain the spread of the virus. up to now, our analysis has focused on the events of the lockdown of wuhan -the epicenter of the novel coronavirus outbreak, it would also be interesting to study the impact of lockdowns and/or the social distancing measures in the destination cities in reducing and containing the spread of virus. indeed, chinazzi et al. ( ) point out that travel restrictions to and from mainland china impact the global pandemic of the covid- only if transmission within the community is simultaneously reduced by % or more, which suggests that social distancing at the destination cities is crucial in preventing the possibly asymptomatic transmission from the source city. moreover, quantifying the effect of social distancing on virus transmission is especially relevant to the stage of pre-epidemic community spread when a person who is not known to have traveled to affected countries, or to have had contact with an infected person becomes infected. as shown in table a in the appendix, within the few weeks after the wuhan and hubei lockdowns, various human mobility restrictions were imposed on other chinese cities outside hubei. as described in table a , the "lockdowns" in destination cities varied in their . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . degree of strictness, from building entrances checkpoints to establishing quarantine zones, and from public transit shutdowns to strict limits on the inflows into the city, outflows out of the city, as well as within-city population movements. we interpret the human mobility restrictions in the destination cities as an enhanced social distancing policy, because the "lockdown" rules in the destination cities are not as strict as those implemented in wuhan. in this section, we use the variations in the destination cities' "lockdown" policies to study how the effects of inflows from wuhan and other cities in hubei province on the spread of covid- cases in the destination cities are impacted by the changes in the destination cities' lockdown policies, which would drastically impact the within-city population movements in the destination cities. specifically, we estimate the following specification that is a modified version of the regression specification described by equation ( ): where the new variable lockdown i,t is a dummy that takes value if time t is a date after destination city i's "lockdown" date, if at all; and otherwise, where the lockdown dates of the cities outside hubei are listed in table a . if city i never implemented any formal lockdown policy, the dummy is always . therefore, the coefficients, β κ and β κ , respectively, measure the impact of the lagged inflows from wuhan and hubei κ days earlier on the destination cities' current new cases before the city's imposition of its "lockdown," while γ κ and γ κ represent the effect on destination cities' of wuhan and hubei inflows after the imposition of the city's lockdown. if enhanced social distancing that comes from the "lockdown policies" imposed at the chinese cities outside hubei is effective in reducing the spread of the virus from population flows from the epicenter of the virus, then we expect that γ κ and γ κ to be smaller than β κ and β κ , respectively. see panel c of table for the evidence from wuhan lockdown on within-wuhan population movement. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . in figures (respectively, figure ), we plot the estimated coefficients, β κ and γ κ (respectively, β κ and γ κ ) in panel (a), and their differences in panel (b) for the lagged effects of inflows from wuhan (respectively, non-wuhan cities in hubei) on the daily new cases in destination cities outside hubei province. we find that the estimated lagged effects of inflows from wuhan and other cities in hubei before the destination city's lockdown, if any, show little change compared to the coefficients in figure however, the coefficient estimates of lagged inflows after the destination city's lockdown policies appear to be insignificant and indifferent from zero on almost all lags. in panel (b) of figures - , we plot the differences between the estimated effects pre and post the destination cities' lockdown policies. we find that the differences between the estimated coefficients pre and post destination city lockdowns are positive and statistically significantly at at-least % level for (respectively, ) of the first ten lagged population inflows from wuhan (respectively, other cities of hubei), and the other differences in lagged estimates are statistically insignificant. these results suggest that the enhanced social distancing policies in the destination cities are effective in reducing the impact of population inflows from the source cities of wuhan and other cities in hubei on the spread of -ncov virus in the destination cities. this in turn implies that population inflows from the epicenter contribute to the spread of infection in the destination cities only before the social distancing measures are applied; it appears that after implementing their various control measures, cities adopting an extended lockdown can flatten the upward trajectory of the virus. in this paper, we quantify the causal impact of human mobility restrictions, particularly the lockdown of the city of wuhan on january , , on the containment and delay of the spread of the novel coronavirus, and estimate the dynamic effects of up to lagged population inflows from wuhan and other hubei cities, the epicenter of the -ncov outbreak, on the destination cities' new infection cases. we find that the lockdown of wuhan reduced inflow into wuhan by . %, outflows from wuhan by . %, and within-wuhan movements by . %. using counterfactual simulations with these estimates, we find that the lockdown of the city of wuhan on january , contributed significantly to reducing the total infection cases outside of wuhan, even with the social distancing measures later imposed by other cities. we find that the covid- cases would be . % higher in the chinese cities outside hubei province, and . % higher in non-wuhan cities inside hubei, in the counterfactual world in which the city of wuhan were not locked down from january , . we also find that there were substantial undocumented infection cases in the early days of the -ncov outbreak in wuhan and other cities of hubei province, . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . but over time, the gap between the officially reported cases and our estimated "actual" cases narrows significantly. we also find evidence that imposing enhanced social distancing policies in the chinese cities outside hubei province is effective in reducing the impact of population inflows from the epicenter cities in hubei province on the spread of -ncov virus in the destination cities elsewhere. the results from our analysis provide valuable causal evidence on the role of human mobility restrictions on the containment and delay of the spread of contagious viruses, including the -ncov virus that is now ravaging the world. enhanced social distancing in the destination cities, and, if an epicenter can be identified as was the case for the city of wuhan in china, a lockdown, can play crucial roles in "flattening" the daily infection cases curve, giving the stressed medical system a chance to regroup and deal with the onslaught of new infection cases. although our study focuses exclusively on the effect of human mobility restrictions on the spread of -ncov virus in china, our estimated results can have general implications to other countries in their fight against the novel coronavirus. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . https://doi.org/ . / . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . ( ) and ( ). the control and treatment groups for models - are described in the text. fixed effects of city-pair and daily are included in all columns in panels a and b, and fixed effects of city and daily are included in all columns in panel c. standard errors are clustered at the daily level. *** significant at the percent level. ** significant at the percent level. * significant at the percent level. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . ( ) and ( ) of table . *** significant at the percent level. ** significant at the percent level. * significant at the percent level. . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . https://doi.org/ . / . . . doi: medrxiv preprint . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . https://doi.org/ . / notes: this figure plots the dynamic effects of lagged inflows from wuhan (left) and other cities in hubei (right) from estimating equation ( ). we add spline smoothing fit curves (in red) using the rcspline function and plot the % confidence intervals (the vertical green whiskers). . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the (which was not peer-reviewed) the copyright holder for this preprint . https://doi.org/ . / . . . doi: medrxiv preprint . cc-by-nc-nd . international license it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint . it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint ( ). we add spline smoothing fit curves using the rcspline function and plot the % confidence intervals (the vertical green whiskers). . it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint ( ). we add spline smoothing fit curves using the rcspline function and plot the % confidence intervals (the vertical green whiskers). . it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint notes: this table provides summary statistics on the count of total confirmed cases as of february , , and on daily average population inflow, outflow, and within-city flow between january and march in , and on permanent population gdp as of december , for cities with different level of controls. . it is made available under a author/funder, who has granted medrxiv a license to display the preprint in perpetuity. is the the copyright holder for this preprint human mobility networks, travel restrictions, and the global spread of h n pandemic a familial cluster of pneumonia associated with the novel coronavirus indicating person-to-person transmission: a study of a family cluster human mobility and the spatial transmission of influenza in the united states the effect of travel restrictions on the spread of the novel coronavirus strategies for mitigating an influenza pandemic natural disasters and population mobility in bangladesh will travel restrictions control the international spread of pandemic influenza clinical features of patients infected with novel coronavirus in wuhan, china effect of non-pharmaceutical interventions for containing the covid- outbreak in china the incubation period of coronavirus disease (covid- ) from publicly reported confirmed cases: estimation and application substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (sars-cov ) the reproductive number of covid- is higher compared to sars coronavirus predictability of population displacement after the haiti earthquake networks in the modern economy: mexican migrants in the us labor market impacts of social and economic factors on the transmission of coronavirus disease (covid- ) in china patterns and limitations of urban human mobility resilience under the influence of multiple types of natural disaster consensus document on the epidemiology of severe acute respiratory syndrome (sars) which means all public transport and private vehicles are banned in the city, all residential buildings are locked down, and residents are not allowed to leave the city. cities in panel b are under partial lockdown, majority of the public transportation has been temporarily shut down, checkpoints has been set up to control the inflow population, and surveillance and tighter controls in each neighborhood. cities in panel c set up checkpoints and quarantine zones, and public transport maintains normal operation. key: cord- - fgtjouu authors: hutton, thomas a title: service industries, globalization, and urban restructuring within the asia-pacific: new development trajectories and planning responses date: - - journal: prog plann doi: . /s - ( ) - sha: doc_id: cord_uid: fgtjouu while industralization programmes have been central to the development of asia-pacific states and city-regions over the past half-century, service industries are increasingly important as instruments of urban growth and change. the purpose of this paper is to establish service industries as increasingly significant aspects of urban development within the asia-pacific, and to propose a conceptual and analytical framework for scholarly investigation within this important research domain. to this end the paper explores a sequence of related themes and issues, concerning the larger developmental implications of urban services growth (or tertiarization), the facets of urban transformation associated with tertiarization, and a preliminary typology of urban service functions which acknowledges the rich diversity of service vocations and stages of development within the asia-pacific. the paper concludes that “advanced services”—specialized, intermediate service industries, advanced-technology services, and creative service industries—will be quite crucial to the development of city-regions within the asia-pacific, with respect to employment growth and human capital formation, to the urban economic (or export) base, to the operation of flexible production systems, and to competitive advantage. the development of these urban service poles will require innovative policy commitments and regulatory adjustments, as will the multi-centred specialized urban service corridors which function as engines of regional economic growth, and which provide platforms for national modernization and responses to the pressures (and opportunities) of globalization. to date, urban and regional development strategies for service industries within the asia-pacific have privileged globalization, industrial restructuring, and modernization aims, but there is also an encouraging record of more progressive planning experimentation in some jurisdictions, incorporating principles of sustainability and co-operative development. there is also increasing interest in policies to support cultural and creative industries among asia-pacific city-regions, informed by some recent urban policy experimentation in this domain. these experiences can offer models for further policy and programmatic innovation in the st century, as service industries continue to play larger roles in urban and regional development within the asia-pacific. introduction: service industries and urban transformation service industries have accounted for an increasing share of labour, output, and trade among the advanced economies of the organization for economic co-operation and development (oecd) over the last quarter century. this phenomenon of sustained growth in services (both in absolute and relative terms) can be observed at the national level among oecd member countries in terms of the changing composition of gross domestic product (gdp) and employment, but is especially pronounced at the urban or city-region scale. final demand service industries (for example retail, education, and most government services) are strongly tied to large metropolitan consumer markets, while intermediate services are even more spatially centralized, reflecting the influence of urban and agglomeration economies on the locational pattern of specialized, contact-intensive services. following the protracted decline of traditional manufacturing, service industries have led employment growth among most advanced city-regions over the last three decades. but the significance of service industries to urban (and especially metropolitan) development extends beyond measures of growth, as important as these are, to encompass comprehensive processes of change. at the broadest theoretical level we can discern intimate associations between service industries and redefining urban socio-economic processes and stylistic innovation over the past century. the growth of high-rise office complexes was an integral feature of the production of modernist urban landscapes, while advanced service industries have been central to the experiences of post-industrialism, flexible specialization, and post-modernism which have transformed urban landscapes, production sectors, and occupational structures over the past several decades. more particularly, service industries are directly involved in fundamental shifts in the urban economic base and industrial structure, but are also deeply implicated in the reconfiguration of regional structure, the metropolitan space-economy, and urban form. the rapid growth of service occupations among the most advanced post-industrial cities has also had profound implications for urban class structure and for the metropolitan social morphology, and is associated with the evolution of urban culture and even political preferences. in addition to these internal facets of urban transformation, service industries are also influential in the repositioning of cities and city-regions within external networks and systems. growth in urban service exports and trade may be significant in the recasting of city -hinterland relations, and in the reordering of national urban hierarchies, and is quite decisive in the emergence of global city-regions. at the apex of the global city hierarchy the most privileged status is associated with high concentrations of specialized banking and finance, and the projection of corporate power, as well as encompassing a more diversified ensemble of specialized service industries. these far-reaching aspects of urban service growth (or tertiarization) are most pronounced within the mature societies of europe and north america, but are increasingly relevant to an appreciation of urban growth and change within asia-pacific cities. the purpose of this paper is to propose a framework for investigating the influence of service industries on urban development within the asia-pacific, with an emphasis on dimensions of transformational change, both within the metropolis, and at the broader urban systems level. this entails an assessment of economic implications of tertiarization for cities and city-regions within the asia-pacific, including the emergence of new urban functions or vocations, and constituent shifts in the urban economic base, employment structure, and mix of industries. advanced or specialized services-especially, banking and finance, business and trade services, professional and 'informational' service activities, among others-are increasingly associated with modernization aspirations among the region's post-industrial, late-industrial and transitional societies, as reflected in development strategies and programmes. however, the parameters of urban change within the asia-pacific associated with tertiarization extend beyond this economic dimension to encompass impacts of service industry growth on urban structure and form, the built environment, social class and social morphology: i.e. the comprehensive facets of transformation (and re-imaging) of cities increasingly engaged in advanced services production, exchange, trade and consumption. our conceptual point of departure is that the expansion of services activity within asia-pacific cities and city-regions represents not only incremental urban growth and change, but, rather, consequential shifts in the role of urban areas within advanced production systems, in the globalization of trade flows, and in new social divisions of production labour. accordingly, the analytical focus will be on service industries and activities which the research literature has identified as 'propulsive' in urban growth and development; i.e. intermediate (rather than final demand) services, specialized service industries, and knowledge-and technology-based or informational services. at the same time, the record of urban services growth within the asia-pacific region discloses wide variations in stages of services development and mixes of service activity from place to place, and this variegation must be acknowledged in the interests of presenting a more rounded perspective on the experience than an exclusive discussion of leading edge examples would allow. indeed, some of the most interesting and instructive stories of urban tertiarization within the asia-pacific concern the juxtaposition of informal and advanced services in transitional societies, with ensuing social, land use, and planning conflicts. following this introduction, the paper offers a discussion of contrasts in developmental trajectories between the 'mature' atlantic core regions and those of the dynamic pacific core (chapter ), including an acknowledgement of industrialization as the dominant development paradigm for much of the asia-pacific since the s. defining elements of advanced urban tertiarization are identified, and are constituted within a taxonomy of global cities' service functions. the following section (chapter ) addresses both commonalities and contrasts in service industry developments among city-regions of the atlantic and pacific cores, and identifies five principal implications of service growth for urban change within the asia-pacific. these include the role of service industries in reshaping urban development trajectories, in the reconfiguration of urban space, and in urban social and cultural change, as well as the ramifications of accelerated tertiarization for the everyday experiences of city life and for urban identity and image. next, the paper offers a typology of urban services development within the asia-pacific (chapter ), derived from levels of services specialization as well as from urban scale. the spatial development of specialized services production within the asia-pacific is described, including both polarized patterns and more extended territories of tertiary sector growth, observed in the form of incipient urban corridors. these corridors (or clusters) represent a functionally specialized form of territorial development which exhibit features of co-operation as well as competition, and in part express policy responses to the pressures of globalization. the two final substantive chapters address planning issues and experiences associated with the development of the urban service sector. the first (chapter ) describes the basic evolution of local policy responses to urban tertiarization over the last quarter-century, from early development control policy regimes imposed to manage negative externalities of rapid service industry growth, to more balanced approaches, which combined developmental as well as regulatory elements. this chapter concludes with a set of important processes and events which have shaped a new policy environment for urban service industries in the early st century. next, chapter extends this discussion, by introducing a framework of six strategic urban policy models which are deployed in cities within the asia-pacific, including experiments in progressive planning (co-operative regional development, sustainable city-regions), as well as familiar models associated with globalization and restructuring objectives. the paper concludes with suggestions for a research agenda, emphasizing developmental and transformational implications of service industry growth for city-regions within the asia-pacific. there are of course different approaches to conceptualizing the units of 'world geography' apart from the standard continental divisions, as a spectrum of historical, socio-cultural, political and economic considerations can be imposed upon the standard geo-physical patterns. for much of the post-war period the idea of a tripartite structure of spheres organised crudely along ideological lines and developmental progress emerged as a descriptive convention, including a developed, essentially democratic-capitalistic 'first world', comprised of a hegemonic us bloc and its allies in north america, western europe, japan and australia; secondly, the comecon (council for mutual economic aid) group of nations, largely dominated by the ussr and concentrated within eastern europe and asia, but also including cuba; and, finally, a 'third world' of 'developing' countries, ostensibly non-aligned, but including many de facto client states of either the us or the ussr. with the collapse of the 'second' (comecon) world (comecon) world - , and the increasing pluralism within the first and third worlds implied in the post-modern viewpoint, there has been a renewed interest in (re) conceiving global geography or world regional patterns. in this regard lewis and wigen acknowledge the tendency of world regional frameworks "to grossly flatten the complexities of global geography", but assert that "some form of baseline heuristic scheme is necessary for teaching and thinking about metageography" (lewis and wigen, : ) . to this end their conceptual preference is to ignore political and ecological boundaries, and to instead focus upon historical processes, to give primacy to "the spatial contours of assemblages of ideas, practices, and social institutions that give human communities their distinction and coherence" (lewis and wigen, : ) , and to consider not only internal attributes but external relations. see martin w. lewis atlantic core, due in large part to earlier industrialization, and a longer record of tertiarization, but there is now a well-developed pattern of higher-echelon global cities within the asia-pacific (rimmer, ; preston, ) (fig. ) . these cities are centres of advanced industrial and services production, and are linked by capital flows, technology transfer, transportation and communication networks, and patterns of cultural exchange and diffusion, typifying aspects of international and global codependency. the second-order world cities achieve a level of global reach via the presence of certain specialized industry groups, propulsive firms, or influential international institutions, and thus comprise essential elements of the global economy. global city status is conventionally associated with comparative concentrations of intermediate banking and finance, headquarters of mncs, 'producer' services (stanback et al., ) and international gateway functions. however, increasingly global city status encompasses other suites of specialized service industries, including design, knowledge, and technology-based activities, in part reflecting scott's thesis concerning the transformational convergence of culture and urban economic development (scott, ) , as well as the competitive advantage of metropolitan cities for creative and informational services (table ) . this city-centred growth pattern is complemented by complex and distinctive forms of regional development, which include ( ) multi-centred urban growth corridors or 'megalopolitan' regions, such as the classic new york -new jersey conurbation (gottmann, ) , and the randstat urban corridor in the old atlantic core, and the example of the 'extended metropolitan regions ' (mcgee, ) of east asia and southeast asia, such as jakarta -bandung, beijing -tianjin, and tokyo -kawasaki -yokohama, within the asia-pacific sphere; ( ) 'lead regions' comprised of innovative industry complexes and propulsive firm networks, exemplified by baden -württemburg, the veneto, the ile de france, and the london-oxford -cambridge technology triangle within the old core (storper and salais, ) , and the kanto plain, orange county, and silicon valley (scott, ) within the pacific sphere; and ( ) incipient trans-border 'growth triangles' (and other geoeconomic constructs), illustrated by the singapore -johore -riau development triangle, and the cascadia metropolitan bio-region of the pacific north west, and, in the atlantic old core, the transmarche region, and the emerging baltic development zone which aspires to foster mutually beneficial development in northern germany, the former soviet baltic states of latvia, estonia and lithuania, and scandinavia. these new and emerging growth territories may exhibit positive spread effects of regional development generally lacking in less advanced zones table principal suites of specialized service industries for global city-regions i (suites of specialized service functions) banking and finance commercial, merchant, and investment banks; securities and brokerages; stock exchanges; non-depository financial institutions; insurance and re-insurance; industrial-commercial real estate and property development corporate control head offices of international and global corporations and multi-nationals; 'propulsive' corporations and firms producer services specialized, export-capable intermediate service industries and firms; corporate law and accounting firms; management consulting, consulting engineers gateway roles major international airports; major seaports; international telecommunications facilities capital functions national capitals; state/province/regional capitals and administration; offices of international agencies tourism and conventions international tourism and convention industries; major international fairs and expositions advanced-technology services software developers; it firms; internet providers; 'dot.com' firms creative services and applied design architects; industrial design; graphic artists/design; fashion design; interior design; landscape design education and knowledge major national and international universities and colleges; r&d operations and science parks; major 'think tanks' and other research/ knowledge-based institutions culture and heritage major museums and galleries; national libraries and archives; culturally defining heritage buildings, sites, and precincts of the global economy, and suggest possibilities of functional complementarity and reciprocal specialization, as well as the familiar exigencies of competitive advantage. in the aggregate, these characteristics-technology-intensive production, high quality economic infrastructure, productive human and social capital, superior external trade mechanisms and capacity, and the distinctive spatial patterns of growth described above -constitute defining aspects of development within the world's dominant economic spheres. these attributes affirm the exalted economic status of the mature atlantic core and the dynamic pacific core, define the trajectory of development at the leading edge of change and transformation, and suggest the power of convergence, interdependence, and hierarchy acknowledged as important facets of globalization. while important commonalities can be discerned, there are fundamental contrasts in the development experiences and transformational vectors of the atlantic and pacific spheres, as well as innumerable variations in the circumstances and growth paths of individual nations and regions within each of these dominant, supra-continental realms (see yeung and lo, ) . the inexhaustible differentiation of regional histories, political traditions and structures of governance, culture and geographical and environmental factors are seen to underpin the persistence of variegation and exceptionalism among regions and localities within both the old and new cores. the confluence of exogenous forces, including the rise of mnes, and increasing market integration and technological diffusion, has imposed some measure of developmental convergence and commonality across international space (as well as increasing disparities within urban social structures), but there are after all limits to the homogenizing effects of globalization, as the recent scholarly development literature attests. without denying the impressive global sweep of mnes and speculative capital, it is essential to acknowledge the significance of (largely) localized development influences, such as site and environment, the structures of social networks and civic institutions, and the quality of public policy and regulation. in an insightful book aimed at 'reasserting the power of the local', a number of scholars enrich the discourse on globalization by an elucidation of factors which reaffirm the power of local identity, and which provide some friction to the movement of capital and firms. storper, notably, asserts the significance of 'territorialization' in embedding some specialized forms of economic activity within specific locations, beyond the more generic considerations of urban agglomeration which can bind (especially contact-intensive) firms to central places, such as higher-order service enterprises which cluster within the corporate complex of the central business district (cbd). in this interpretation, a firm or activity is "fully territorialized when its economic viability is rooted in assets (including practices and relations) that are not available in many other places and that cannot be easily or rapidly created in places that lack them" (storper, : ) . this concept of territorialization can also incorporate the quality of civic institutions and civil society as influences on economic development and socio-economic welfare, as disclosed in putnam's seminal study of regional and community development in italy (putnam et al., ) . other important factors of locality that can influence differentiation in patterns of economic growth and development are exemplified by amenity attributes, which may include access to education and learning opportunities, and community levels of tolerance and equity, as well as air and water quality, leisure, and recreational opportunities. thus, the forces of globalization, as powerful and pervasive as they demonstrably are, may be significantly tempered, mitigated, or renegotiated at regional and local levels. this more nuanced interpretation of the interactions and tensions between global imperatives and local (or domestic) factors provides a useful backdrop for inquiry into the comparative developmental conditions between the atlantic and pacific cores, a task that has assumed greater importance both in the wake of the asia-pacific's dynamism over much of the past three decades, as well as the serious downturn that commenced in mid- in many east and southeast asian economies. this crisis, which delivered a major check to the continued growth and progress of many of the leading economies of the region, presents a complex set of economic, socio-cultural and political issues and underlying causes that vary widely from place to place, but certainly includes important structural factors (relating to governance, policy, regulation, and financial supervision), as well as more transitory or cyclical attributes (mcleod and garnaut, ). an apparent recovery process can be discerned in some of the asia-pacific economies, but the experience is likely to be protracted and wrenching for many, as the (now decade-long) recession in japan seems to attest. sustained recovery (and, more pointedly, a shift from growth to development) will require major adjustments to the political structures of asia-pacific states, as well as to the governance of corporations and industrial enterprises, and to the supervision and regulation of banks and financial institutions. both the depth and breadth of this economic downturn (and attendant social and political upheavals), and the quarter century or so of recurrent high growth levels that preceded it, raise questions concerning the contrasting trajectories of development within the mature atlantic economies and those of the new core of the pacific basin, as well as the factors underlying these patterns of differentiation. certainly one of the most salient and defining contrasts in the post-war trajectories of the atlantic and pacific spheres concerns the relative status and roles of the secondary (manufacturing) and tertiary (service) sectors, respectively, and the ensembles of policy, market and socio-demographic influences on these distinctive sectoral specializations. beyond the obvious reality that the leading states of both the pacific and atlantic spheres contain advanced industrial production sectors, and are experiencing growth in tertiary activity, it is important to acknowledge that while the growth of services represents a dominant motif of the economic and social reconstruction of western economies and societies, the accelerated growth of manufacturing industry and employment has been the principal story in the rise of the asia-pacific economies over the past four decades. among the mature economies of the oecd, concentrated within the old atlantic core, this same period has seen a massive contraction of production capacity and labour in basic industries, especially in fordist mass-production manufacturing, manifested most dramatically by wrenching processes of industrial decline (consisting mostly of outright factory closures but also some measure of locational decentralization) within long-established inner-city industrial precincts of large-and medium-size cities, and consequent losses of employment, income and revenue (noyelle and stanback, ) . new industries characterized by flexible specialization processes and technology-intensive outputs have emerged in 'lead regions' and 'new production spaces' (scott, ) within the atlantic core, so aggregate manufacturing output has held up or even increased (by value) in some areas (coffey, ) , but in general manufacturing activity has lost ground in relative terms in most oecd regions. over the past half-century, services have been essential features of the development of metropolitan cities (gottmann, ) . more specifically, intermediate services have emerged as increasingly strategic and propulsive elements of advanced production systems, as observed in successive rounds of industrial restructuring, in new divisions of labour, and in the rise of service-based global cities and new urban service poles (table ) . at the same time, the post-war period has seen among the most advanced societies the sustained expansion of service industries which (with related shifts in industrial production processes) have profoundly changed the economic base, industrial mix, labour force, land use and physical form of city-regions within the atlantic zone. service sector growth has thus constituted a central feature of economic restructuring among advanced nations and regions, with service-type occupations leading employment formation not only in the tertiary and quaternary (or informational) sectors, but also in manufacturing, where the growth of management, clerical, sales and technical workers has exceeded that for direct production workers and operatives in most cases. in general scholarly attention to the growth and development of service activities has evolved as follows: (a) an early interest in the growth of high-rise offices in the cbds of the largest metropolitan cities, including important theoretical and conceptual contributions (gottmann, ) , (b) a stream of empirical studies of office location, emphasizing regional policy implications and urban planning problems (daniels, ; goddard, ) , (c) growing interest in the social ramifications of services growth (bell, ) , (d) a sharper analytical focus on business, 'producer' and other intermediate services, and their role in urban and regional development (noyelle and stanback, ) , and in the operation of 'flexible' industrial regimes, (e) assessments of the global dimensions of services development, especially in banking and finance, as well as in producer services and communications (daniels, ), (f) acknowledgement of the importance of specialized services in the emergence of the 'informational city' and urban society (castells, ) , and (g) explorations of the intersections between tertiarization, occupational shifts, urban class (re)formation, and community-level impacts, especially in the metropolitan core (ley, ) . ( ) producer services as key to flexible specialization production regimes (coffey) ( ) emergence of integrated sevice-technology-production systems ( ) internalized service production ( ) externalized service production ( ) globalized service production ( ) but these structural consequences of tertiarization extend well beyond the economic dimension, as the sustained expansion of service labour (and concomitant decline in bluecollar workers) within the atlantic core regions has led in turn to the reformation of urban society, in terms of social class, community and neighbourhood patterns, culture, and political values and preferences, as documented in scholarly treatments of post-industrial society (summarized in table (a)). the tight spatial bonding of specialized, contactintensive service industries within intricate input -output relations has been instrumental in the reformation of urban structure and land use within the metropolitan core (gottmann, ; hutton and ley, ) . tertiarization has also generated more comprehensive changes in metropolitan structure, as seen principally in the emergence of specialized service nodes and clusters which dominate the space-economies of advanced city-regions, and also in urban form and the built environment, exemplified in the growth of the central city corporate complex, new districts of services production and consumption on the cbd fringe and inner city (including design and technology-based services), regional office and retail centres, and proto-urban forms which incorporate advanced service industries within 'edge cities' (garreau, ) (table (b)) . while tertiarization stands as the definitive and most consequential feature of economic growth and social change among western or atlantic nations and regions over the post-war period, industrialization has represented the principal development modality for much of the asia-pacific since the s and s. (although there have been to be sure important shifts in agriculture and other forms of primary and staple production in many pacific nations.) there is of course considerable variation in the temporal sequencing, specific industry emphasis, scale and stage of manufacturing growth among individual nations (and even among regions and sub-regions), but accelerated industrialization, supported in most cases by state policies and programmes, has been central to the expansion of every high growth asian-pacific state (douglass, ) , including ( ) the japanese ascendancy, seen in the industrial development of the japanese archipelago (especially within the principal conurbations of honshu but also including urban centres in kyushu and hokkaido) over much of the present century, with accelerated development of production in industrial and consumer goods from the s, including see garreau ( ) for an original contribution to our understanding of this spatial and socio-economic phenomenon. i am making a broad distinction here between economic systems in which manufacturing or (alternatively) services are dominant. it is of course possible to perceive services as 'industrial activities', as detailed divisions of 'service industries' are conventionally depicted within sectoral aggregations in standard industrial classification catalogues, for statistical purposes. moreover, there is a general preference for positioning service industries as co-dependent elements of integrated production systems (gershuny, ) . at the same time, industrialization as a development paradigm within the asia-pacific has certainly implied a powerful emphasis on the growth of manufacturing industries, industrial companies and conglomerates, factories and industrial labour, in the form of factory workers, assembly line employment, and operatives. jonathan rigg's analysis of modernization and development in southeast asia includes a special chapter addressing the idea (and reality) of 'the factory world' as a defining feature of this experience (rigg, : - ) . table defining attributes of advanced urban tertiarization defining conditions within highly tertiarized cities (a) urban industrial structure, economic base, employment and class sectoral/industrial structure tertiary sector larger than secondary sector; service industries growing faster than manufacturing industries both in relative and absolute terms industrial output services share of urban/regional gdp growing faster than manufacturing share market orientation/production linkages intermediate sector services growing faster than final demand services; specialized services and manufacturing co-dependent elements of advanced production systems urban economic base services comprise large and increasing share of urban economic base; significant and growing volume of specialized service exports and trade employment . % of urban employment in service industries occupational structure rapid growth of executives, managers, professionals; emerging social division of service labour favouring knowledge-and technology-based service workers, design, creative and cultural services urban class structure emerging hegemony of 'new middle class' (ley, ) of upper-tier service cohorts urban social morphology extensive social upgrading (gentrification) in older inner city neighbourhoods; growth of inner city loft housing and 'live-work'/'work-live' studios; increasing social displacement and inter-group tensions (b) urban spatial structure, space-economy, form, image and identity urban/metropolitan structure service industries dominant elements of urban core and (established or incipient) metropolitan sub-centres urban space-economy specialized service clusters and corridors dominant features of urban/ metropolitan space-economy (cbd corporate complex, seaports and airports, distribution centres, retail centres, higher education institutions, government and public administration, business parks, r&d parks] inner city landscapes new and emerging precincts of specialized services: applied design, creative and cultural services; internet providers and 'dot.com' firms; cultural centres; higher education; professional sports and entertainment; public recreation; live-work studios and new artist/artisan neighbourhoods urban form mix of modernist-post-modernist urban forms: high-rise office precincts in cbd and metro sub-centres, as well as new services domiciled in 'reconstructed' services production and consumption landscapes within inner city and inner suburbs; 'edge cities' and proto-urban forms on the metropolitan periphery infrastructure derived demand for transportation and other infrastructure associated with urban tertiarization identity post-industrialism; post-modernity image 'global' or 'world' city (hall, friedmann, sassen) ; 'informational city/society' (castells) ; 'transactional city' (gottmann) the expansion of global-scale industrial conglomerates and mncs; ( ) the origins of takeoff growth among the newly industrializing countries (nics), with accelerated industrialization initiated in taiwan and hong kong in the s, and singapore and south korea about a decade later (mcgee and lin, ) ; ( ) the later emergence of the 'threshold' or 'near' nics, notably malaysia and thailand, which retain important bases of agriculture and staple production outside the principal metropolitan zones, but which have experienced substantial manufacturing growth over the past two decades; ( ) the tumultuous growth and transformation of china, dating from the ideologically impelled industrialization programme enunciated in the series of -year economic plans commencing in the period - , to the industrial stimulus generated by the economic liberalization policies launched in , and then to the more recent expansion of advanced manufacturing in the lower yangtze, pearl river delta, and certain other coastal regions; ( ) the larger role played by industrial development in the transition of other populous agrarian nations, notably indonesia and the philippines; and ( ) the current economic restructuring programme in vietnam, associated with the 'doi moi' policy of economic and social renovation. in addition to these important examples, industrialization also represents a goal (or ideal) of lagging states within the region, such as laos, burma and north korea, although the realization of these industrial aspirations has been seriously impeded by a prejudicial mélange of factors including war, flawed development models, governmental corruption and administrative incompetence, lack of capital and other resources, and isolation. these national industrialization programmes and trajectories also featured important urban and regional dimensions. by the s, the asia-pacific sphere included a number of world-scale industrial metropoles, such as tokyo, nagoya, osaka, seoul, taipei, hong kong and shanghai, while by the s manufacturing emerged as an important feature of the metropolitan space-economies of southeast asian primate cities, including bangkok, jakarta, kuala lumpur, and manila (douglass, ) . beyond these large-scale urban industrial complexes, manufacturing activity increased within the metropolitan periphery, exurban areas, and even rural zones, for instance in the lower yangtze region, within the chinese special enterprise zones (sezs), within designated receptor areas (such as penang) for japanese foreign direct investment (fdi), and within desakota areas of east and southeast asia, proliferating the spatial milieux for industrial production in the region. even in pacific america, within which urban tertiarization processes are generally advanced, some city-regions have exhibited greater buoyancy in manufacturing than many of the older industrial cities of the great lakes region and eastern seaboard, within the broadly defined atlantic core. over the past two decades, los angeles, the san francisco bay area, seattle and even vancouver have experienced significant growth in advanced manufacturing such as aerospace and electronics (and in some basic production industries as well, such as garment production) within their regional territories, in contrast to the record of industrial decline in many other north american metropolitan areas, although to be sure they have also experienced high growth in service industries, and contractions in some traditional industries. at the end of the th century, then, industrialization represented the dominant trajectory for many states and regions within the asia-pacific, constituted a significant aspect of growth (together with specialized services) in some of the more advanced economies of the pacific realm, and remained an aspiration of lessdeveloped, agrarian and staple-dominated countries in the region. these industrialization trajectories will continue to be highly influential in the development of asia-pacific cityregions in the new century, but it is equally clear that service industries will emerge as increasingly significant features of urban growth and change, a theme we will explore in the following chapters. to date there has been relatively little scholarly attention paid to the development of service industries and employment within the asia-pacific, with the notable exception of case studies of cities within which services (especially advanced or 'higher-order' services) are playing significant roles (taylor and kwok, ) , and specialist studies of banking, finance and investment, and transportation and communications. the research emphasis has tended to be on multinational service corporations and international trade in services (waelbroeck et al., ; thrift, ; unctad, ; sieh-lee, ; lasserre and redding, ) , rather than on services development and associated issues for cities and city-regions. this situation reflects, to some extent, the pervasive influence of industrialization as a development paradigm within much of the pacific realm, emphasizing the primacy of manufacturing and industrial production within the growth trajectories of many asia-pacific states, regions and societies. the hegemony of the industrialization paradigm has created a kind of shadow effect within the scholarly literature on the economic development of the pacific basin, within which services are customarily treated as elements of the traditional urban retail or commercial sector, as essentially ancillary activities which can be effectively subsumed within industrialization processes and systems, or as special, almost aberrant features of exceptional cases such as hong kong and singapore. indeed, many of the region's leading service industries and corporations (notably banks, trading companies, and ocean freight lines) were established to facilitate manufacturing growth and the expansion of trade in goods, thus comprising essential features of the asia-pacific's industrialization experience. moreover, service industries, including modern, advanced services, are now sufficiently well-represented in a broad sampling of national and regional jurisdictions, and are now so increasingly central to the economic and social transformation of pacific cities, that a more incisive investigation of services growth trends and associated impacts is clearly merited (o'connor, ) . the centrepieces of urban service sectors within the asia-pacific are of course the large national and multinational service industry corporations, including the major banks and financial institutions (including brokerages and securities companies), trading houses, property firms, integrated construction and development corporations, and the leading airlines and hotel groups. these are, as is well known, highly concentrated within to illustrate, rigg's generally excellent and insightful treatment of 'modernization and development' in southeast asia offers only a single index reference to 'services' (and that one brief discussion in the text pertains to informal service activities), in the interest of focussing on the very important developments in agriculture and manufacturing, although modern service industries have certainly been instrumental to the growth of singapore, are of more than marginal significance to the development of malaysia and thailand, and are important features in the economic landscapes of the primate cities of southeast asian nations, including indonesia, the philippines and vietnam. the region's first-and second-tier global cities, especially tokyo, osaka, seoul, taipei, hong kong, singapore, los angeles, san francisco, and sydney. many of these financial corporations and other large service enterprises have become extensively globalized, enhancing the status of the cities within which they are domiciled; but a significant proportion of these corporations have been seriously damaged by the events of and after, and there have already been a number of major bankruptcies, with, no doubt, more to follow. the corporate power of cities within the asia-pacific is therefore pervasive, but by no means immutable. at a smaller scale, we can identify the full range of intermediate or producer services which, as in the mature economies of the atlantic sphere, typically include corporate legal firms and accountancies, management consulting firms, public relations and personnel companies, technical service operations, as well as planning and architectural firms which cater wholly or in part to the corporate sector. at the vanguard of growth and change there are also an expanding number of firms in the computer software and knowledge industry groups that are so crucial to the progress of advanced, information-based economies. in general, however, this intermediate services subsector (comprised mainly of small-and medium-size firms) is somewhat less well-developed in asia than is the case among the leading regional and national economies of europe and north america, where the producer services are seen as essential to the efficient operation of flexible production regimes, and have constituted the most dynamic elements of these economies and labour forces over the past two decades. this disparity is reflected in the large balance of trade deficits in specialized services incurred by most pacific asian nations (daniels and o'connor, ) . we can provisionally attribute the (relatively) less developed nature of intermediate services within the asia-pacific to a number of factors and conditions, including the perhaps obvious observation that services are generally at a less mature stage than among the more advanced atlantic core economies. however, there are also important structural factors as well. these include, notably, contrasts in the regulatory conditions and legal and contractual regimes between countries, which impose different kinds and levels of requirements upon firms domiciled within these jurisdictions. within many of the western societies these regulatory and legal regimes have become exceedingly complex and demanding, giving rise to specialized intermediate service firms which provide expert advice to corporations on a subcontracting basis, as the demand arises. within the asian realm, as we have already noted, many of these specialized service inputs are generated either internally within the corporation, as is the case with some of the larger korean and japanese conglomerates; or, as is the practice in many firms in china and southeast asia, are supplied by a network of advisors defined by kinship and social relations. moreover, there has been a substantial (if spatially and temporally uneven) growth of producer services within the asia-pacific, reflecting "the wide socio-cultural heterogeneity in this region and the distance between trade centres" (ho, : ) . at the leading edge of change among a growing number of asia-pacific societies, the implications of service industry growth may at least selectively reflect the experience of the mature economies of the atlantic-centred core, within which specialized service industries ( ) represent both agents and outcomes of economic restructuring, as well as leading elements of overall urban and regional transformation; ( ) constitute (with technology and manufacturing) co-dependent elements of advanced, flexible production systems; ( ) are associated with important, and in some cases defining, new divisions of labour and social class reformation; ( ) reflect, in part, increasing income levels and consumption rates within host societies; and ( ) have become significant elements of inter-regional and international trade flows, reflecting inter alia externalization tendencies and aspects of competitive advantage for specialized services production, export, and trade. as observed among the mature industrial (or post-industrial) societies of the atlantic sphere, too, service industries within the asia-pacific tend not to be distributed evenly across national territories, but are instead concentrated within urban regions, reflecting the spatial association between consumer services and their residentiary markets, and the even more centralized patterns of highly agglomerative intermediate (or producer) services. there is also a tendency toward greater levels of specialization in services production among larger cities, although there are to be sure some notable exceptions to this. this correlation between tertiarization levels, growth rates and degrees of specialization is of course most easily observed among the region's major corporate centres, such as tokyo, hong kong, and singapore, but the familiar spatial manifestations of service industry growth (cbds, corporate complexes, commercial strips and nodes, and the like) are features of a growing roster of asia-pacific cityregions, although their specific form may be locally distinctive. the study of specialized service industries within the asia-pacific, then, as in the atlantic sphere, necessarily implies an urban emphasis. these important commonalities notwithstanding, even at the most generalized level of analysis we can readily identify some defining distinctions between current services growth rates, development patterns and interdependencies within the new core of the asia-pacific, and those observed within the atlantic-centred old core. as in other facets of urban development, it is essential to achieve an appreciation of signifying contrasts in urbanization experiences in the asia-pacific, as distinct from the patterns of urban development within the atlantic core (lin, ) . these contrasts include the following: . generally higher growth rates of service industries and employment among asia-pacific nations and city-regions over the past decade and a half, reflecting more incipient stages of tertiarization in many asian jurisdictions and, broadly, more buoyant economic conditions over the past two decades or so. by way of contrast, service growth in europe has been (as daniels notes) slow or even stagnant (daniels, ) . (it must, however, be acknowledged that the depressed condition of certain asian currencies and financial markets are diminishing growth expectations in financial and service sectors among certain business centres over the short-to medium-term, and ensuing political instability and social unrest will almost inevitably exacerbate those impacts. moreover, urban service sector growth rates will inevitably slow among advanced cities with high existing levels of services labour, including singapore, hong kong, and japanese cities). asia-pacific city-regions, which represent in many cases significant departures from the more linear patterns of service industry growth common to the old atlantic-centred core. these contrasting tertiarization trends and processes are in part a consequence of the widely varying stages of overall development among specific national and regional jurisdictions, but are also associated with important (and in some cases decisive) policy factors and local development strategies. . the diversity of services-production linkage patterns among asia-pacific economies, which to some extent may follow the services externalization and subcontracting processes widely documented among european and north american firms, but are also exemplified in other respects by the distinctive nature of industrial organization in 'lead' asian economies in which large integrated corporations (keiretsu in japan, the chaebol in south korea) maintain internalized service supply; by the intricate entrepreneurial networks based on kinship relationships in parts of east and southeast asia (hsing, ) ; and by the intimate spatial linkages between industrial production and service providers observed in exurban or countryside production regimes in certain regions of china (marton, ) . . variation in the reconfiguration of metropolitan space-economies to accommodate the introduction of new, specialized service industry nodes and clusters, which follow to some extent the locational tendencies of services in advanced economies and city-regions; while at the same time exhibiting persistent spatial patterns derived from more traditional systems of urban and regional economic development, as exemplified in the desakota areas of southeast asia and japan, and, at a smaller scale, the intimate juxtaposition of advanced and informal service activities in central areas of developing societies (leaf, ) . in the most advanced cases, new spatial patterns of specialized services production include clusters of design, creative services, and advanced-technology service industries within reconstructed inner city precincts. . distinctive divisions of labour within urban service industries, which may appear to mimic the western model at the apex of the occupational hierarchy (i.e., the growth of managers, professionals, knowledge-based and advanced-technology workers), but also display substantial variation, derived in large part from localized culture, class structures and traditions, the pre-existing base of service workers, and region-based entrepreneurial or mercantile cultures. to these broad points of contrast in the tertiarization experiences of the asia-pacific and atlantic spheres, it is essential to highlight important differences in policy approaches and roles. within the asia-pacific, we observe a spectrum of (sometimes quite assertive and even grandiose) developmental policies and programmes designed wholly or in part to promote the growth of specialized service industries. these include the highly dirigiste approaches of japan (shapira et al., ) and singapore (ho, ) , within which central governments have assigned leading roles to advanced service industries in support of urban and national economic transformation, and enhanced roles for service industries in local economic development strategies and policies. in contrast, public policy approaches toward services among western societies have tended to emphasize regulation, including zoning, development control, and growth management, in addition to mostly episodic experiments with developmental policies, and only very exceptional attempts to undertake service industry 'megaprojects' on the heroic scale of numerous asian cities. although there are profound differences in stages and levels of tertiarization among asia-pacific city-regions, as we shall shortly see, the implications of urban service industry growth can be structured within five broad categories: ( ) a set of essentially propulsive and transformational impacts, within which services (especially advanced intermediate and knowledge-based service industries and institutions) are assigned leading roles in urban, regional and even national development; ( ) the (direct and indirect) impact of services on the internal restructuring and reconfiguration of the city-region, including regional structure, the metropolitan space-economy, and built form; ( ) services and the reformation of urban class and the city's social morphology (or ecology); ( ) implications of rapid tertiarization for the experiences of everyday life; and ( ) the role of services in the transformation of the city's image and identity. it must be emphasized that these are by no means neatly compartmentalized, discrete categories of consequence, however, as there are innumerable interactions and interdependencies between and among them. first, rapid tertiarization may have the potential to significantly accelerate the processes of urban growth and change, and to quite fundamentally modify basic urban economic functions or vocations, as reflected in the recomposition of the metropolitan industrial structure, economic base, and regional gdp. at one level, this process evokes the idea of post-industrialism, which positions service industries and occupations as ascendant features of the urban economy in a context of (relative or even absolute) contractions in basic manufacturing. however, in the asia-pacific setting the growth of specialized services can be seen as a concomitant element of advanced production systems, national modernization programmes, and globalization strategies of central and regional governments. these strategic aspirations are by no means fully realized, but they do underscore the importance of advanced services to the future development of the region. as is well known, tertiarization within many asia-pacific city-regions is impelled both by market and policy factors. this latter tendency is particularly marked in the region, as we can instance numerous examples of assertive public policy efforts both at central and local government and administrative levels designed to accelerate tertiarization (and/or deploy tertiarization as an instrument of broader economic and socio-economic transformation). examples of the deployment of policies for services in the interests of supporting or promoting transformational change include (a) synergies between national economic liberalization policies and local development strategies which have accelerated tertiarization processes (including advanced services) among designated chinese cityregions, (b) intersections between national industrial policies and urban economic programmes which have supported specialized service functions among japanese metropolitan cities, (c) ensembles of national development programmes and regulatory adjustments designed to enhance the growth of advanced, export-oriented services, as in the case of singapore since the mid- s, (d) central government support for strategic service industries as instruments of national development, accompanied by complementary local land use initiatives, as in the case of finance, producer services and information technology in malaysia, and (e) the more episodic (or less committed) support for service industries within (often somewhat schizophrenic) clusters of local development and growth management plans in sydney, melbourne, seattle, san francisco, vancouver, among other cities. the second category of urban tertiarization impacts concerns the role of services in change within the internal form and structure of the metropolis or city-region, and reflects the profound and comprehensive impacts of service industry development on the spaceeconomy of the contemporary city. the internal reordering of metropolitan space associated with rapid service industry growth incorporates processes which are multifaceted and interdependent: demand for services generates growth among service industries and firms to create a new sectoral mix within the city's economic base, and new patterns of services production and consumption as observed in the emergence of high-rise office complexes, secondary business centres, specialized service clusters (for example tertiary education and medical complexes), and new retail landscapes. these developments have visibly reconstructed urban structure and form in many american cities, but in some european cities have been situated more carefully within older districts, creating a more subtle and complex urban form, while in asia (for example in shanghai and osaka), preservation has been subordinated to the imperatives of accelerated restructuring, and has been in policy terms an afterthought at best. while market forces have constituted agents of urban respatialization, public authorities have deployed services as instruments of internal metropolitan reconfiguration within the asia-pacific, as in (a) the construction of new financial and corporate this urban 'policy schizophrenia' is associated, typically, with institutional conventions and operational practice within city and metropolitan governments. in most cases the urban 'plan' is prepared by staff planners, with input from other professionals and the broader community, and often emphasizes regulation, in terms of statutory development control functions and instruments (such as zoning, developing by-laws, and land use policies) and modern growth management modalities. by way of contrast, local economic development strategies are formulated by separate economic advisory groups, business interests, community groups and ngos, or special council committees or bodies appointed by (and accountable specifically to) the mayor or council chair, and are therefore often informed by quite different (and even oppositional) values and visions. a principal motivation behind the development of the la défence corporate complex was to protect the historic built environment of central paris from the kind of massive demolition and displacement impelled by office development in many other cities, by initiating a new 'cbd' outside the metropolitan core. this has been to a large extent realized (apart from exceptions such as the maine-montparnasse office-tower on the rive gauche), but the preservation of buildings and streetscapes in the central core of paris has been a series of struggles over the past century and a half (sutcliffe, ) . complexes, both to accelerate economic restructuring at the local level, and to support national modernization goals (as exemplified by the massive pudong project across the huangpu river from the established central district of shanghai) (yeh, ) , (b) the development of modern commercial and telecommunications infrastructure to support future world city aspirations (as seen in kuala lumpur), (c) the promotion of specialized financial and producer services in established cbds and designated subcentres to support world city status, and to maximize regional competitive advantage (with singapore presenting a vivid example), (d) the reclamation of land resources for accommodating the expansion of spatially or topographically constrained cbds (hong kong), and (e) the development of commercial and business megaprojects to diversify local economies, advance international business and financial relationships, and compete more effectively against other (often larger) centres within regional settings (as is the case with the minato mirai project in yokohama) (hutton, ) . more generically, public authorities also respond to infrastructure demand (for example airports and transit systems) derived from growth in services industries and activities (daniels, ) . the growth of service industries and occupations within asia-pacific city-regions also has important social implications, representing a third major set of urban tertiarization impacts. here, the growth of (especially advanced) service industries and related occupational cohorts generates an increasingly tertiarized labour force, which daniel bell described as a pre-condition for the emergence of a post-industrial society, over a quarter century ago (bell, ) : a contested idea, to be sure (gershuny, ) , but a seminal and prescient contribution in many ways. within the highly tertiarized city, the growth of specialized services leads to significant socio-spatial effects, including the familiar pattern of social upgrading within inner city neighbourhoods, and the formation of new suburban communities comprised largely of service workers, but also the recent emergence of a 'new middle class' of higher-echelon service labour (ley, ) . the rise of this new middle class of elite service workers (professionals, executives and managers, entrepreneurs and creative services occupations) as a presence in the inner city, a larger process than earlier, more incremental experiences of gentrification, comprises individuals who view the metropolitan core as a place to work, live, and recreate, leading to the transformation of the central city with respect to structure, land use, form, and lifestyles. there are also broader cultural connotations associated with the new middle class, as seen in shifts in tastes, values, behaviours, and even political affiliation. this new middle class enjoys a hegemonic status within the most highly tertiarized cities in the region, such as vancouver, seattle, san francisco, and sydney, and comprises the ascendant social cohort within singapore, tokyo, and hong kong, but is also observed as a growing presence (with some local variation in specific features) within the central districts of seoul, shanghai, guangzhou, and kuala lumpur, among other cities. the fourth set of impacts of service industry growth within cities of the asia-pacific concerns changes at the micro-level, what braudel termed the 'structures of everyday life' (braudel, ) . although much of the scholarly analysis of tertiarization has emphasized change within the three strategic categories described earlier, a more nuanced appreciation of the more intensely localized implications of growth in services is essential to attaining an appropriately rounded profile of the process. these include, for the purposes of illustration, the impact of service industries and the growth of service occupations on the quality of working life, and on localized displacement and dislocation at the neighbourhood and household levels (chua, (chua, , , especially within a context of industrial decline or restructuring. there is considerable potential for research on the important gender aspects of tertiarization, which may include the tendency for over-representation of females within many service occupations and industries. within the highly tertiarized societies of the old atlantic core, the past several decades have seen both the impressive progress of women within some of the credentialized service occupations, for example in law, accountancy, and planning, but also a more discouraging tendency for women to congregate in more menial, poorly paid and distinctly marginalized positions. there are also important linkages between the growth of service industries in asia-pacific cities and international migration. australian scholars have suggested that immigration can enhance the 'productive diversity' of economies, and more specifically that skilled immigrant professionals can support urban services exports, for example in sharing or transferring within the firm knowledge about overseas markets (aislabee et al., ) . lin observes that characteristics of mobility, flexibility and entrepreneurial skills are defining attributes of hong kong migrants (lin, : ) , enhancing their attractiveness to receiving urban societies and business communities. in certain cities, recent immigrants are over-represented both within entrepreneurial and management occupations, but also among more menial service occupations; this is especially the case in large global cities (sassen, ) . again, as in other facets of tertiarization, we can discern within asian labour markets some powerful resonances of trends initially observed in mature cities of the atlantic core, but there are also quite distinctive, persistent traditional socio-cultural contexts to consider. the importance of maintaining a perspective on the more localized implications of tertiarization also acknowledges the reality that the expansion of service industries by no means involves just the formal business, professional and managerial activities that have led growth among the western urban economies, but also the full range of neighbourhood shops and markets, casual restaurants and bars, and personal and retail services (to say nothing of other service establishments that may operate on, or even over, the margins of legality and social acceptance). in many asian cities, these smaller scale service operations may be viewed as an extension of the traditional population of informal service workers (itself a contested term), service activities which occupy the urban interstices between the more formal corporate business and retail structures. these can be seen as persistent features of the central city, not only among the megacities of southeast asia, such as bangkok and jakarta, but also within the downtown spaces of modern world cities such as tokyo. they are not simply residual activities, but essential, if often undervalued, operations that support the more formal service economy in different ways within the metropolitan core, including the provision of food and beverages (yasmeen, ) . these small-scale, low-return service firms survive by virtue of entrepreneurship, reliability, thrift, and knowledge of where the commercial niches exist in the modern city, and they contribute to the vitality and identity of the urban place. a final aspect of urban transformation associated with tertiarization is derived from an accumulation of the changes described earlier-economic, social, cultural, physical, and spatial-and is commonly articulated as a metamorphosis of the city's character, as perceived by citizens (constructed as 'identity') or as reconstructed by government and corporate entities and external agencies ('image'). the perceived image of a city can be substantially altered by comprehensive processes of tertiarization, as seen in the repositioning of singapore and hong kong as post-industrial, specialized service centres, although usage of decidedly obsolete nomenclature such as 'newly industrializing economies' is surprisingly persistent, as are outdated tropes like 'little dragons' or 'little tigers' (cartier, ) . in some cases national governments have supported specialized service industry projects as quite deliberate instruments of urban re-imaging, as seen in the creation of international banking and producer services in the pudong development in shanghai, and in the construction of the petronas towers in the central area of kuala lumpur. these initiatives are designed in part to underscore a commitment to modernity, and by extension to symbolize national economic progress and aspirations to global status and engagement, but also to supplant traditional (or, more pejoratively, 'backward') industries and related social groups. these more grandiose visions can be contested, especially where the elite beneficiaries of advanced service industry growth (for example professionals and managers in financial and business services, as well as cronies of rulers and oligarchs) represent a particularly visible and privileged expression of dichotomous 'development' as set against the condition of the urban masses in places like jakarta and manila. the issue of urban identity may also be deeply problematic, as the rapid growth of services elites within asian-pacific cities can presage decisive shifts in power relations (political as well as economic) within the urban community. in some cases the ascendancy of upper-tier service workers represents a new socio-economic and socio-political hegemony, implying a coincident subordination of traditional industrialsector cohorts, as well as an exacerbation of income disparities. as in other aspects of urban tertiarization within the asia-pacific, contrasts in scale and stages of development are significant, as are tendencies toward exceptionalism when case studies are subjected to closer analysis. thus, baum concluded that the sustained growth of specialized service industries, advanced-technology activities and related occupations in singapore, coupled with comprehensive public housing programmes and education investments, has resulted in a predominantly professionalized (as opposed to polarized) occupational and social structure within the city-state (baum, ) . in hong kong, where specialized services have also driven urban growth and socio-economic change (kwok, ) , the post-colonial record since includes growing poverty (about residents earn less than $ per month), attributable in some part to the inadequacies of the secondary school system, a situation which one legislator fears may lead to 'serious social instability' (lee cheuk-yan, quoted in far eastern economic review: october ). at a larger scale, a combination of market liberalization and selective tertiarization in certain chinese cities, with attendant political and bureaucratic corruption, has generated income polarization rates approaching or even exceeding the american level. this striving for new urban identities in the chinese case, with its repressed tensions and conflicts, can be seen in the shanghai government's preference for 'high class' individuals (well-educated, with the right attitudes, outlooks and professional profiles) for the glittering new towers of the pudong project (halliday, ) , a far cry indeed from the earlier communist exaltation of the urban industrial worker and fraternal colleagues in the pla and in rural peasant communes. we can also discern highly localized intersections of globalization and tertiarization in the reconstruction of identity at the district level. the proliferation of transnational retail and food services within commercial complexes is of course a ubiquitous phenomenon, as observed in places like shinkjuku and shibuya stations (and commercial subcentres) in tokyo. in hong kong, the incursion of service industry commuters in the new territories has transformed the social identity of certain of the post-war industrial communities, as seen in the transformation of tsuen wan from 'hakka enclave' to 'post-industrial city' (johnson, n.d.) . in the case of singapore, the last decade has seen the demise of the kampung kopi-tiam (informal eating places, serving authentic local fare) as a result of relentless modernization (chua, ) , and the almost total disappearance of traditional rural life, while other local retail and shopping districts have been subject to the reformation of identity associated with the tastes and behavioural preferences of affluent expatriate populations. chang deploys the term 'expatriatization' to describe a "spatial transformation in which land use increasingly reflects an expatriate bias", as typified in holland village, a local commercial centre within an affluent residential district of singapore, but one which "reflects the influence and influx of global cultures" (chang, : ) . in the most highly tertiarized cities within the asia-pacific, exemplified by san francisco, seattle, vancouver, sydney and singapore, a distinctive urban profile associated with dominant service industries and occupations within the financial and producer services now incorporates a more recent overlay of technology specialists, notably internet providers, software developers, and the so-called 'dot.com' firms. many of these firms have been concentrated within "new service production landscapes" within or proximate to the central area, exemplified by 'silicon alley' and telok ayer in singapore, yaletown in vancouver, belltown in seattle, and the northeast mission and south park districts of san francisco (hutton, ) . these technology-based service firms (which also include graphic designers, who exemplify the production synergies of technology and culture in applied design) typically exhibit employment structures dominated by young entrepreneurs and 'techies', with distinctive skills and lifestyles, underscoring both the new social divisions of labour in the urban service sector, and the highly volatile nature of urban identity in the post-modern, globalized metropolitan order. over the last years, the number of these technology-intensive firms within inner city production districts has contracted significantly, as part of the crash of the dot.coms. however, new survey research has disclosed the emergence of 'hybridized' firms combining creativity and technology toward the production of high-value goods and services, signifying a new phase of development within the metropolitan core of advanced societies (hutton, ) . these trends therefore demonstrate both the volatile nature of recent phases of service industry development, as evidenced by the accelerated processes of transition and succession, as well as the distinctive role of the inner city as site of innovation. stages of urban service industry development within the asia-pacific the preceding narrative described important distinctions in the broader tertiarization experiences as observed within the old atlantic core and the new core of the pacific realm. at the same time, there are also quite profound differences in stages or levels of service industry development among (and within) asia-pacific nations, just as there are important contrasts in levels and rates of industrialization. the construction of typologies of urban tertiarization among asia-pacific city-regions is hampered by data constraints and conceptual problems, and more recently by the shortterm impacts of the crisis of currencies and financial markets of and afterwards. although this crisis was seen to depress prospects for the asia-pacific generally, the impacts have been spatially quite uneven, and as the fiscal-economic malaise spread within the regions of the asia-pacific, and within social and political domains, it is by no means beyond the realm of possibility that the medium-to long-term outlook for certain urban centres has been seriously compromised. thus, to the overall perception of dynamism among the urban service sectors and industries of the pacific region, we must add considerable uncertainty. there is also a clear need at the outset to acknowledge the increasing complexity of overall urban development patterns, within which (we are arguing in this paper) service industries are increasingly playing larger roles. to illustrate, terry mcgee, in a retrospective paper on his concept of 'the southeast asian city' published in following years of extensive fieldwork, observed that "while urbanization levels will continue to rise there will be much differentiation between countries which will make the construction of any one model of the southeast asian city impossible" (mcgee, : ) . in this interpretation, models (or typologies) cannot reasonably function as templates of "supposedly universalizing tendencies" (mcgee, : ) , but rather should reflect the importance of specificity and exceptionalism in urban development experiences. it may at least, however, be possible to structure a basic and highly simplified typology of tertiarization stages among representative classes of asia-pacific city-regions, as a means of gaining insights into the range of urban tertiarization trajectories, the nature of specialization in services among city-regions, and the association between service development and urban hierarchy in the region. here, a typology of urban service centres within the region, while inevitably masking considerable nuance, may at least serve to depict some basic features of functional differentiation. while tertiarization stages and levels vary widely among asia-pacific city-regions, service industries are certainly performing significant roles in urban growth and development across a range of city types and urban scales. there is by no means a strict correlation between urban rank-order and level of service industry specialization within the asia-pacific region. to illustrate, there are medium-size cities with considerable global reach in terms of corporate power and important specializations in strategic service industries, such as finance and information technology (notably singapore and seattle), while a number of mega-urban regions (for example jakarta and manila; see mcgee and robinson ( ) ) contain limited advanced services capacity relative to their overall urban scale. therefore, a typology of cities engaged in specialized services production and trade should incorporate 'suites' of services specialization and developmental progression, as well as attributes of scale and hierarchy. accordingly, table positions asia-pacific cities and settlements within seven principal categories of specialized tertiary activities, distributed spatially within urban clusters, corridors, or 'outposts' within the western and eastern littorals of the pacific basin (depicted cartographically in fig. ) . at the peak of the pacific urban hierarchy we find tokyo and los angeles, the dominant corporate control centres within this extensive economic and trading zone. these massive city-regions contain to be sure huge concentrations of manufacturing, and, indeed, exhibit greater industrial strength than many of the first order global cities of the atlantic realm, such as london, paris, and new york. both tokyo and los angeles have important, global scale advanced-technology industrial sectors, situated within their metropolitan and immediately proximate territories, including orange county (in the case of los angeles) (scott, ) , and the new production spaces of the tokyo metropolitan region (tmr) (fujita and hill, ) . however, while both tokyo and los angeles retain an impressive base of modern manufacturing capacity, their most insistent claim to global city status rests on their downtown complexes of international banking and finance, and headquarters of mncs, supported by highly specialized producer services and superior international communications systems and transportation networks. los angeles and tokyo are also global centres of cultural production and dissemination, media concentration, and applied design and creative industries. they contain major universities of high international standing, including ucla and usc (los angeles), and tokyo university and waseda within the japanese capital. of these two pacific regional first-tier global cities, tokyo has conventionally been ranked as the leading centre, in view of its base of multinational head offices, and more particularly, its concentration of major banks, securities firms and trading companies, but this status may need to be reconsidered in light of the fall-out from the crisis (and, indeed, the failure to effectively address structural and institutional problems in the national banking and financial sector over the last decade). tokyo has considerable underlying industrial and overall economic power, but there is certainly the prospect of serious erosion in its financial sector over the mediumterm at least, which may jeopardize its position within the triumvirate of highest-order world centres (which also includes london and new york). fig. . asia-pacific urban service centres: hierarchy and specialization. doel and beaverstock ( ) observe that despite the claims and assumptions of fully globalized capital markets, the asian financial crisis has had relatively little negative impact on london and new york banks and financial corporations. indeed, many of the european and north american investment banks, for example, have (at least quietly) rejoiced in the misfortunes of the japanese banks in particular, as the asian financial crisis has (at least for the moment) 'seen off' their japanese competitors. category within our provisional typology includes six second-tier global cities: hong kong, singapore, seoul, osaka, san francisco, and sydney. despite significant contrasts in urban scale (to illustrate, there is seoul with a population of over million; and singapore at million), each represents a major asia-pacific financial, corporate and business centre. they are all characterized by ( ) very large cbd corporate complexes of head offices, multinationals, international banking and financial activity and producer services; ( ) strategic gateway functions and major international airports; ( ) major universities and knowledge-based institutions; ( ) large concentrations of executives, professionals, managers, entrepreneurs and other higher-order service occupations within the metropolitan labour force, and ( ) a powerful international corporate 'reach', competing in some sectors or areas with other second-(and even some first-) tier global cities. in each of these six asia-pacific financial and business centres, we also observe new precincts of specialized services within the inner city, including design and creative services, multimedia and post-production firms, internet providers and dot.com firms, reflecting the 'advanced tertiarization' stage of urban spatial development depicted in table this typology serves to highlight very broad variations in tertiarization levels among selected city-regions within apec, but even a cursory examination of individual cases discloses considerable variation in the trajectory of restructuring and service industry development within each category. for example, both singapore and hong kong specialize in advanced service industries, including finance and banking, producer and other high order services, tourism and convention activities, and higher education. each is now a major exporter of services; hong kong is ranked as the th leading exporter of services globally (hang seng bank, ) . manufacturing has declined from . % of hong kong's employment in , to only . % in , a level comparable to that of the most highly tertiarized atlantic core societies (asian development bank, ) . upper-tier service industry professionals, managers and entrepreneurs constitute the dominant social class in hong kong (kwok, ) . however, hong kong's emergence as a centre of specialized service production and trade has been impelled principally by an exceedingly liberal regulatory regime, while singapore's restructuring trajectory has been enhanced by a more direct application of policy measures. following a brief but sharp recession in , the singapore government resolved to transform the city-state from a branch-plant industrial enclave to a regional (and world) centre of tertiary production and trade, with the aim of becoming the 'switzerland of asia' by . this overarching economic development and transformation goal has been to a large extent realized, and singapore now represents a policy experience that other nations (notably china) are endeavouring to emulate. although hong kong's classically laissez-faire approach contrasts sharply with singapore's explicitly dirigiste development strategy, selective public policy initiatives have facilitated hong kong's economic restructuring. as observed by taylor and kwok ( ) , hong kong experienced an accelerated transformation process over three decades, from an 'industrial metropolis' (export manufacturing phase) in the s, to a 'postindustrial' status (information service phase) over the s, and emerging as an 'international metropolis' by the s. a sequence of policy and (especially) physical planning measures were deployed to promote economic transition and transformation, including the industrial new town programme of the s, the expansion of the hong kong cbd eastward toward wanchai and causeway bay in the s, and the recent investments in transportation infrastructure, as in the linking of hong kong with guangzhou by expressway, and the construction of the international airport at chek lap kok. there have also been substantial new public investments in tertiary education, training and housing, underscoring a substantial government commitment to upgrading the quality of hong kong's human resources and social capital. these investments and land use policy initiatives suggest that contrasts between singapore's and hong kong's approaches to economic transformation which insist on sharply dichotomous contrasts may be somewhat overstated, although the extent (and sustained commitment) of direct policy intervention in the singapore case is in many respects singular. our third category includes second-and third-tier global cities, which feature large and generally fast-growing service sectors, established on a base of world-scale manufacturing and industrial production capacity in each case. we can identify two sub-categories (table ) within this aggregation: first, three 'advanced' business and industrial centres (nagoya, kobe and taipei) situated within leading east asian economies; and secondly, a set of 'transitional' urban centres which still possess some features of early phase industrialization and a relatively large informal sector, including 'floating' or transient labour contingents (beijing, shanghai, guangzhou, bangkok, and kuala lumpur). however, each of these large cities exhibits relatively high growth in producer services, including engineering and business services. other defining attributes of these centres are ( ) important international gateway roles, ( ) major public and private sector investments in higher-order services infrastructure, and ( ) ambitious local/metropolitan strategies for new, specialized service industry roles and 'vocations', supported in most cases by national government policies and projects. the japanese experience of tertiarization provides particularly instructive case studies, in light of the priority accorded industrial development up to the s, the lead role of the central government and its constituent ministries over the last decade in assigning new development roles incorporating specialized service and technology-based industries for the major cities, and the outcomes of these initiatives among different japanese cities (edgington, ) . in general, the central government has been concerned both with the need to maintain a leading edge position in industrial production within the asia-pacific, while preparing the large cities for more advanced roles in specialized services industries, both for the domestic economy, and for trade purposes. much of the research on economic restructuring in japan has emphasized 'hard services,' notably technology, and its role in transforming both industrial production modes and urban economic structures (glasmeier, ) , while another major body of scholarship deals with the transformation of tokyo, while hong kong has initiated over the past years numerous specific projects and programmes to support the expansion of service industries, singapore has enunciated policies and programmes to promote strategic services (e.g. banking and finance, producer services, and it) within more formal policy statements and structures, consistent with the city-state's distinctive policy culture and administrative styles. the recent expansion of design and technology-based services in heritage districts outside the cbd represented one of the few 'spontaneous' (or unplanned) economic phenomena in the city-state's recent history (interview with urban redevelopment authority official, july ), although there is now policy support for cultural industries administered by the tourism development board. japan's first-order 'world city' (masai, ) . important themes concerned with tokyo's transformation include tensions and conflicts between the capital's international roles and local functions (fujita, ) , and the problems of accommodating (or, prospectively, relocating) central government functions from tokyo's metropolitan core (isomura, ) . however, there has also been some important work focusing on the restructuring (and, more specifically, tertiarization) of other principal japanese city-regions. these experiences include the economic restructuring of tokyo (machimura, ) , the expansion of advanced services such as finance, information services, and education in the major industrial city of nagoya over the last two decades (hayashi, ) , and the new emphasis on advanced knowledge-based service industries for the transition of yokohama from gateway port (and 'shadow city' for tokyo), to a more independent role as international business centre (edgington, ) . the experience of metropolitan transformation among the largest chinese city-regions over the past several decades represents a striking example of the influence of policy priorities within a command economy, and the potential for accelerated tertiarization following an adjustment of central government policy direction. following the industrialization policies and programmes of the period over the s, s, and s (including the ruinous 'great leap forward'), chinese cities "were endowed with a massive and diffuse manufacturing capacity, and provided with few incentives (until the last decade) to develop the services sector" (hamer, : ) . the economic policy reforms of (and more specifically) the mid- s embodied a recognition that modernization would require the more efficient deployment of cities and their resources, and thus heavy manufacturing was increasingly decentralized to outlying areas, and services (especially financial and producer services) were encouraged, both by economic planners in beijing, and by local authorities. in order to achieve growth in advanced production and transition to a more knowledge-based economy, hamer estimates that "up to % of the local labour force will have to be employed in the producer services sector" (hamer, : ) , a proportion that seems high even by the standard of more advanced oecd cities, but is perhaps nonetheless indicative of municipal aspirations. lin also underscores the crucial role of cities in the modernization of the chinese economy as represented by their concentrations of advanced service industries and occupations which enable higher levels of creativity, efficiency, and internationalization (lin, : - ) . recent trends in beijing, shanghai, and guangzhou serve both to generally underline the growing importance of service industries within the development trajectories of major chinese cities, while at the same time demonstrating the exceptionalism of specific cases. in beijing, an acknowledgement of the inappropriateness of the soviet-style heavy industrialization of the ancient capital, with its attendant environmental and displacement impacts, sets the stage for a new development strategy reasserting political, administrative and cultural roles. the goal of the - master plan (approved october ) is to develop the "historic city into a modern, economically prosperous and socially secure international metropolis of first class world standard in services, infrastructure and environmental quality" (mao and jin, : ) , representing an abrupt departure from the industrial city model of the s and s. as the contemporary beijing master plan invokes the re-establishment of the capital's traditional administrative and cultural roles, shanghai's current transformation recalls financial and trading functions de-emphasized following the ascendancy of the communists to power. immediately prior to the ascension of the chinese communist party in , shanghai's financial sector included foreign banks, private and government banks, trust companies, and currency exchangers: "with such a large number of financial institutions, representing a high degree of concentration of capital, shanghai was in a position to control the economy of the entire nation" (fung et al., : ) . a succession of five-year plans emphasized the primacy of manufacturing for shanghai's industrial transformation, with a particular emphasis on heavy industry and the production of capital goods. by the completion of the first five-year plan (in ), shanghai had experienced a transition from an outward-looking financial centre to the leading industrial centre of an almost autarkic chinese state. the economic policy reforms of the late s and mid- s presaged the onset of yet another fundamental change in economic priorities for shanghai, and, more specifically, for the reconstitution of shanghai's financial, trading and business service functions. to a considerable extent, this massive effort in economic restructuring is intended to offer china a strategic access to the global economy (yeh, ) , but (at least at a subtextual level) the question of achieving a competitive position vis-à-vis hong kong in financial and trade services must be acknowledged. in this respect, shanghai has certainly attracted an impressive quantity of investment in banking and commercial (and supporting public) infrastructure, as well as a growing number of mncs and mnes, but has not yet achieved the high concentrations of domestic and expatiate professional expertise in specialized services that is a defining hallmark of highest-order global cities. (indeed, as kris olds has observed, shanghai's globalization strategy has been highly dependent on the engagement of the 'global intelligence corps' of elite professionals; olds, ) . here, hong kong is likely to hold a competitive advantage over other chinese cities over the short to mediumterm by virtue of the territorialization (storper, ) of this expertise and specialized human capital. the two fundamental shifts in shanghai's development trajectory over the past several decades can be interpreted empirically. in , the 'tertiary sector' (i.e. commerce, finance, communications, science and technology, education and culture) constituted . % of shanghai's regional gdp. following years of investment in manufacturing capacity and employment, this proportion was reduced to only . % by . the intensive promotion of advanced service industries during the s resulted in an increase in the tertiary sector's share of gdp to % by , while shanghai's economic development strategy called for an increase in this proportion to about % by (fung et al., ) , led by the advanced services complex in the pudong redevelopment mega-project. (shanghai's service sector grew by % in , and by % in ; chreod ltd, ) overall, shanghai's experience of accelerated industrialization and subsequent re-tertiarization must represent one of the most dramatic episodes of economic restructuring among large metropolitan cities in the post-war period. guangzhou is, of course, smaller than beijing or shanghai, but it performs strategic gateway roles for guangdong province and southern china as a whole, and has undergone significant processes of restructuring and tertiarization (xu and yan, ) . as in other large chinese cities, economic policy priorities following entailed the transformation of guangzhou from a 'consumer city' to a 'producer city'. this strategy of large-scale industrialization was perhaps less fully realized than in the case of shanghai, because of the persistence of entrepreneurial traditions in the province, and guangzhou's distance from the national capital, which enabled at least a degree of autonomy. building on its well-established gateway and entrepôt functions, guangzhou was strategically positioned to immediately benefit from the opening up of chinese coastal cities. in the period - , growth in services exceeded that for agriculture or manufacturing, with lead tertiary sector industry groups including finance and corporate support services (nanjiang, ) . guangzhou is the urban centre for the pearl river delta economic region, which represents (with the lower yangtze region and southern fujian) major growth regions and access points for china to the broader asia-pacific and global markets (johnson, ) . the issue of whether guangzhou can extend its regional role more fully into the national realm remains an open question (tsang, ) , as are the 'terms of co-existence' with hong kong following the latter's post-colonial status as a special administrative region of the prc as of july . there is to be sure potential for complementarity as well as competition as characteristics of the relationship between guangzhou and hong kong within the pearl delta extended urban cluster, a theme to be addressed in more detail below, but over time guangzhou will aspire to greater shares of the region's international financial and business activity. the fourth aggregation of city-regions depicted in table comprises metropolitan areas characterized by the advanced tertiarization of the urban economy and labour force. this fourth category of asia-pacific cities includes two sub-groups: first, advanced, highly tertiarized cities with substantial manufacturing capacity and associated labour cohorts, and propulsive corporations, notably seattle, melbourne, and yokohama; and a larger contingent of specialized services cities with relatively modest industrial production sectors, including vancouver, portland, fukuoka, and brisbane. in many respect these jurisdictions embody features of service industry development observed within the mature urban and regional economies of the old atlantic core, which typically include (a) a dominant status for services within the metropolitan industrial mix, export base, and occupational structure; (b) the formation of corporate complexes within the cbd; (c) the emergence of new, creative services (culture, applied design, multimedia) on the cbd fringe and inner city; (d) the influence of suburban business centres and 'edge cities' in regional multinucleation; (e) intersections between services growth and changes in urban housing markets; and (f) the increasing role of services in the reformation of urban identity, politics, and lifestyles (ley and hutton, ) . at the same time, many of the city-regions within pacific america and australasia also exhibit tendencies common to other asia-pacific metropolitan areas, such as (relative) economic dynamism and higher growth rates in services, and are also linked to asia-pacific cities, markets and societies by increasingly diverse networks of trade, investment, immigration and travel. as a crucial intersection of two principal processes of urban development, large-scale immigration, especially from asian societies, has in important respects augmented urban tertiarization processes, reinforcing entrepreneurial, professional and management occupations, and contributing to export services trade by enhancing the connectivity between trading centres. we can therefore position these cities as geographically peripheral, but functionally integral, nodes of the asia-pacific urban system and as important examples of a distinctive stage of urban tertiarization within the pacific realm. the fifth category within our provisional typology of asia-pacific cities engaged in services production includes several southeast asian 'mega-urban' regions, jakarta, manila, and (more tentatively) ho chi minh city. the emergence of relatively small service sector occupational elites within mega-urban city-regions such as jakarta, and manila must be set against a vastly larger informal sector of hawkers, vendors, and peddlers, which mcgee described as the urban 'proto-proleteriat' (mcgee, ) . even in second-tier cities, such as bandung, economic restructuring incorporating both industrial development and tertiarization has promoted a deeply polarized social structure (pribadi and sofha, ) . the imposition of advanced, high order services within the central and inner-city areas of southeast asian mega-cities has produced a distinctive juxtaposition of socio-economic classes, typified in part by the persistence of shanty towns, squatter settlements and informal sector activities proximate to high-rise office towers, high-end shops and boutiques, and other accoutrements of the later th-century corporate complex (leaf, ) . as leaf observes, the explanation for this notionally incongruous pattern of traditional social morphology and modern capitalist development features "lies in the segmentation of urban land markets…which is now most commonly expressed in terms of formal and informal sectors…derived from early patterns of land use not governed by market principles" (leaf, : ) . in the case of jakarta, in which about three quarters of the population live in informal settlements (kampung), social class differentiation is expressed "not so much by zone or neighbourhood, such as what one would expect in the capitalist city, but at a more minute scale, between streetside and inner block locations within the same neighbourhood" (leaf, : ) underscoring the complex (and often deeply problematic) impact of economic restructuring on urban social structure within developing societies. the continuing economic crisis within southeast asian economies has no doubt impacted the poor disproportionately, but has also damaged the small service elite of professionals, financial and business services workers within the region's primate cities. in addition to the direct effects of this crisis on the employment and incomes of the service elite themselves, it seems likely that wider ramifications may include the diminution of the advanced services production capacity of these developing economies, as well as an erosion of the (already small) middle and upper-middle classes within their respective societies. ho chi minh city (formerly saigon) also exhibits a highly dualistic socio-economic structure, but differs from manila and jakarta in some important respects. more particularly, the introduction of the 'doi moi' (renovation) economic policy has forcefully inserted a before the 'crash' of there was a generally growing constituency favouring economic, social, cultural and even political association among the nations of the pacific basin, derived in part from a shared vision of mutual economic interests and visions of progress, as well as a preference among some observers to view the 'modernist project' in pacific asia through the western critical tradition (preston, ) . in the short term at least the fiscal and economic crisis of the past years in asia has diminished the enthusiasm of some in the americas and australasia to be associated with the wider concept of the 'asia-pacific'. there are also signs of a more 'inward' (i.e. intra-asian, as opposed to transpacific) sensibility on the part of (for example) japanese corporations and the chinese, japanese and malaysian governments, although the motivations for these attitudinal changes vary. former japanese vice-minister of finance eisuke sakakibara, for example, suggests that the membership of the us within apec precludes the latter from being a 'true regional organization,' while vice-minister ito observes that "[t]he task for asian countries is to ensure that regionalism in asian really complement global trading and financial systems, like other regional arrangements in north america and europe" (quoted in t. armstrong, 'asia is going it alone', the globe and mail, monday february : all). market presence within an established socialist political and social order, with polarizing outcomes for ho chi minh city's labour force and society. advanced services are emerging as defining elements of the new ho chi minh city as depicted in an approved mural extolling " years saigon and ho chi minh city: industrialization and modernization", the modernist imagery underscored by a dominant motif of point towers (drummond, ) . in this regard ho chi minh city is something of a 'frontier city', characterized by significant autonomy from hanoi, a situation somewhat analogous to that of guangzhou in southern china, which operates as a bastion of market enterprise in contrast to the more formal cultural and political style of beijing. at the same time, hanoi too is endeavouring to expand its engagement with the global economy in its development strategy, while maintaining a measure of local policy protection for long-established informal services, implying a bipartite planning approach to service industries (leaf, ) . the final two categories depicted in the typology of asia-pacific urban service centres comprise more narrowly specialized cities and settlements. category includes important port cities with (in most cases) substantial industrial sectors, and some service industries ancillary to port functions, but otherwise relatively underdeveloped advanced tertiary sectors. this set of port/industrial cities includes, to illustrate, pusan, kaohsiung, kitakyushu, oakland, and tacoma. a number of these cities are aggressively pursuing industrial diversification strategies in order to escape dependence on older (in some cases distinctly obsolescent) manufacturing activity; these include kitakyushu, pusan, and kaohsiung. each of these cities is actively promoting new service industries which are seen as more progressive development modes or vocations for the st century, and at least two, pusan and kitakyushu, are joint signatories to official co-operation agreements. the seventh category includes generally smaller cities and settlements specializing in travel and tourism. these include tropical centres, such as denpasar and kona, as well as the major skiing and winter sports centres of sapporo and whistler, the latter now the largest ski resort in north america. these centres may also be candidates for major international events: sapporo has hosted a winter olympics, while whistler is an integral part of vancouver's bid for the winter olympic games. as we have seen advanced services exhibit strongly polarized spatial patterns within the asia-pacific, reflecting the power of urban and agglomeration economies, and the locational centrality of higher-order services in metropolitan areas. at the same time, we can envisage the emergence of spatially extended territories of specialized services production and exchange at the broader regional level, configured as multi-centred urban corridors. these corridors (or clusters) comprise in most cases regions with a dominant first-or second-order global city and a chain of interdependent, and generally smaller, but nonetheless important urban centres. the conceptual bases for the emergence of these there is of course some ambiguity in this terminology, but in general corridors encompass essentially linear arrangements of cities, as exemplified in the pacific north west corridor (vancouver -seattle-portland), while clusters can describe patterns of functionally linked (but dispersed or non-linear in form) cities within extended regional settings (for example the california bay area, which includes san jose, the silicon valley, oakland and berkeley, as well as san francisco). specialized functional territories can be traced to gottmann's seminal idea of megalopolis (gottmann, ), whebell's theory of corridors as urban spatial systems (whebell, ) , and mcgee's notion of extended metropolitan regions (mcgee, ) . they perform strategic service functions (including finance, corporate control, administration, information and communications, cultural and gateway roles), are linked both to regional production systems and to global networks of services trade, and exhibit aspects of complementarity as well as competition. fig. shows the location of major urban service corridors or clusters within the asia-pacific sphere: five in east asia (central japan -honshu corridor, the lower yangtze corridor, the pearl river delta cluster, and the taiwanese and korean corridors); one in southeast asia (the southern malay peninsula corridor); one in australasia (the southeast australian corridor); and three on the pacific coast of north america (the southern california corridor, the california -bay area cluster, and the pacific north west corridor). reflecting the corporate power of the asia-pacific's firstorder global cities, the two most important extended urban services territories are the central japan -honshu corridor, which includes tokyo, yokohama, osaka, nagoya, and kyoto; and the southern california corridor, incorporating los angeles, anaheim, orange county, and san diego. these first-tier metropolitan services corridors contain truly global-scale concentrations of most of the specialized service industry suites listed in table , including banking and finance, corporate control, producer services, gateway functions, advanced-technology and creative services, education and culture. however, there are certainly global-or international-scale service industry concentrations situated within other principal service corridors and clusters, as exhibited in table . these include, to illustrate, the california bay area (global-scale advanced-technology and creative services, higher education, tourism), the korean corridor (banking and finance, corporate control, gateway roles), the pearl delta (banking and finance, corporate control, gateway roles), and the southern malay peninsula (banking and finance, gateway roles, advanced-technology services, education). within the more compact urban service clusters, the expansion of specialized services territories acknowledges the need to accommodate back-office functions and local services in smaller regional centres, and to situate new airports and port facilities, university sites, and research and development facilities in peripheral or exurban areas outside the dominant metropolis, with the pearl delta cluster as an example. culture, amenity and lifestyle may constitute supporting elements of intra-regional services development in some cases, notably in the transboundary pacific north west corridor. advanced services have been crucial to the post-staples development of the pacific north west; at the same time, the amenity provided by wilderness areas is widely seen as a positive inducement to the specialized services and advanced-technology industries which increasingly define the economic base of this region, and is also embedded in social values and lifestyles. within certain of the larger territories, notably the central japan -honshu corridor, the recent development of metropolitan service centres reflects the changing division of production labour at regional and even national levels, presenting possibilities of reciprocal specialization in services within hierarchical and otherwise competitive urban systems. at the same time, there are to be sure examples of the 'uneasy co-existence' of national primate and second-and third-order cities within extended clusters, derived from hegemonic inter-city relations; the examples of seoul and pusan, and tokyo and osaka, come to mind. the dynamics of regional competition and complementarity can further be illustrated by reference to the pacific north west corridor, which includes the three major ports of vancouver, seattle, and tacoma. there is to be sure considerable competition among the three ports (which is likely to increase as major shipping lines continue to rationalize their trans-pacific rotations), but we can also observe aspects of specialization and complementarity: seattle and tacoma are major container ports, while vancouver specializes in bulk commodity exports and cruise ship travel (the port of seattle has recently increased its efforts to attract cruise ship traffic, with at least a measure of success.). at a broader level, the reciprocal strengths of services specialization observed in seattle, vancouver and portland enable the north west corridor to compete in some trade sectors with the san francisco bay area cluster (for example in international gateway functions), about km to the south. in each case the emergence of these multi-nucleated, interdependent services production corridors may presage the reorganization of regional economic space to enable economies of scale, scope, and specialization, in response to the pressures (and opportunities) of globalization. within certain of these corridors, for example the yangtze delta cluster, and the southern malay peninsula corridor (incorporating singapore and the kuala lumpur -putrajaya -cyberjaya technology corridor) this developmental aspiration is a matter of quite explicit political strategy (see for example the discussion in corey, ( ) ). in the japanese case, the central government has attempted to promote complementary clusters or corridors of advanced-technology industries and services within three hierarchical levels, in order to maximize efficiency gains, and minimize damaging inter-regional competition (edgington, ) . there is a perceived need to transcend the everyday rivalries of regional competition, in order to promote powerful international-scale banking and finance, corporate control, education and culture services, production and trade platforms, along the lines of mature counterparts within the old 'atlantic core', such as the us northeastern 'megalopolis' corridor, the paris-ile de france region, and the london-oxford -cambridge triangle. a demonstration of the mutual benefits of inter-city complementarity and co-operation in this sphere may in turn facilitate broader efforts at inter-regional and international colloboration, as encouraged by douglass ( ), among others. at the moment, cities within the region tend to see themselves as entities within essentially competitive international urban systems, with an obligation to devote more policy attention and public resources to fostering competitive advantage, at the expense of planning efforts designed to enhance local welfare (thornley, ) . over the last decade or so urban policy approaches to service industry development have evolved significantly, reflecting in part a more informed appreciation of the centrality of advanced services to urban development. however, in other respects shifts in planning approach in this policy domain incorporate responses to the challenges and opportunities of globalization, and innovation in planning styles, as well as efforts to reconcile regulatory and distributive issues with important developmental aspirations. as in the fundamental processes of urban tertiarization described in preceding chapters, we observe a number of important contrasts in urban service industry policies between societies of the pacific and atlantic 'cores', notably a much stronger emphasis on growth and development aspirations among the former, as well as some commonalities. accordingly, this chapter will entail a discussion of defining shifts in urban policy approaches to service industries, leading to a presentation of six leading models of service industry models, together with illustrative reference cases, in the following chapter. we can identify several principal phases of local planning and policy responses to the growth of the urban service sector over the past quarter century. broadly, the initial period emphasized development control policies, to manage negative externalities associated with growth in speculative office development; the second phase included developmental programmes, acknowledging the increasing significance of service industries to local economies and labour markets; and the third period has seen more assertive policies which deploy advanced services as instruments of industrial restructuring, modernization, and globalization, as well as increasing policy innovation and experimentation. first, the rapid growth of offices within central city areas over the s and s gave rise to a suite of regulatory local planning policies toward the urban service sector (daniels, ) . planning concerns during this period included the implications of rapid office development for the over-specialization of the urban economy, for the displacement of non-office industries and housing, and for long-distance commuting within the regional commuter shed. indeed, the journey-to-work problem, shaped by the expansion of the cbd's office complex, and the simultaneous decentralization of the urban residential population and labour force, was broadly seen as a defining metropolitan planning issue in many city-regions (davis and hutton, ) . the planning response to high levels of central city office development over the s and s included both increasingly stringent development control policies for the core (including downzoning, the imposition of annualized development quotas or thresholds, and fiscal measures), as well as efforts to promote new office subcentres within suburban areas. local planning responses to office activity and other service industries in this critical policy phase at times took on a strongly ideological tone. in britain and in other parts of western europe, left-leaning councils actively discouraged service industries, which were seen as displacing traditional manufacturing industries. this essentially prejudicial local attitude toward service industries was in part conditioned by research which subordinated the tertiary sector to secondary manufacturing within the urban or regional economy, based on measures of export performance, productivity, and sales and employment multipliers. however, to some extent stringent local planning controls on (especially office-based) services were strongly influenced by political opposition to the speculative property market, which was seen to favour office development over industry and housing, reflecting higher returns on investment (roi) for office development relative to other land use categories. examples of this ideologically derived planning response to urban tertiarization included the greater london council and most inner city boroughs during the s and early s. urban authorities continued to experiment with development control options for service industries, but by the mid- s a more positive (or balanced) local policy approach was in evidence among a growing number of local authorities. this more favourable local policy posture toward office activity and other service industries was influenced both by the implications of industrial decline in many large-and medium-sized cities, impelled by the collapse of traditional fordist industry, as well as by new research which underscored the key roles played by specialized services in advanced (daniels, ) . more particularly, the specialized intermediate (or 'producer') services were identified as crucial to the operation of 'flexible' production systems, to high-wage urban labour formation, to industrial productivity, to the urban export base, and to local revenues. in this new situation, urban governments and planning authorities began to introduce policies for (at least selectively) encouraging important service industries, notably banking and finance, transportation, business services, higher education, and tourism (coffey, ) . examples of more positive local planning and policy instruments for the urban service sector are depicted in table , together with corresponding instances of development control and other regulatory measures, across a spectrum of local policy fields. table contrasts planning approaches toward service industries according to preferences for 'developmental' or 'growth management' policy objectives, although in practice many local authorities tended to implement a blended suite of promotional programmes and regulation . however, important examples of quite dramatic policy shifts can be referenced, notably within cities of the broadly defined asia-pacific region. in the well-known case of singapore, a short, sharp economic downturn in the mid- s led almost immediately to aggressive new policies favouring specialized, high-value, exportable services, in part reflecting concerns about the prospects for singapore's manufacturing industry and regional entrepôt roles. in hong kong, the colonial government assertively supported the expansion of office activity and other key intermediate services, exemplified by the territorial expansion of the cbd, by public investments in education, and by increased international marketing (taylor and kwok, ) . and in vancouver, a centre-left city council approved an economic development strategy which set out a series of policies and programmes to foster important service sectors and industries, together with co-operative measures to be undertaken among key institutions, labour cohorts, and business groups (city of vancouver, ) . at the same time, the city of vancouver continued to co-operate with the regional planning authority, the greater vancouver regional district, in managing externalities of rapid growth in services, for example by supporting office development in designated regional town centres (rtcs), exemplifying the tendency to 'blend' both regulatory and developmental programmes within local policy suites. the experimentation with development programmes for urban service industries over the s and s marked a significant departure from the strongly regulatory promotion of a better spatial balance between employment generation and housing growth a principal policy goal information services support for active marketing of tertiary services in domestic and international markets promote or market secondary centers in the suburbs (e.g. by publicizing cbd/ suburban rent differentials) government liaison/ 'partnerships' lobbying of central/middle tier governments to promote tertiary industry development; including for changes in government policy/regulatory environments (e.g. in the sphere of finance and banking, air bilaterals) support for government decentralization policies involving public and private sector tertiary employment source: after hutton ( ). experiences of the previous two decades. however, major changes in urban development conditions in the most recent period have led to a new phase of urban policy innovation, with policies for advanced services at the heart of much of this experimentation. these new policy conditions include the following processes, trends, and events: . continuing processes and pressures of globalization, stimulating local and regional policies promoting competitive advantage at the city-region level (as well as wellpublicized protests and demonstrations), but also encouraging interest in the possibilities of co-operative programmes between cities and local governments situated within 'extended metropolitan regions ' (mcgee et al., ) . . the severe (although spatially differentiated) impacts of major exogenous shocks on regional and national economies, including the aftermath of the / experience in new york, the bali night-club explosion of october , and the lingering effects of the fiscal and economic crisis in the asia-pacific. these impacts have included inter alia sharply diminished air travel and tourism in many regions, increasing unemployment, and problems of corporate illiquidity and bankruptcies. we can also acknowledge the recent impact of sars (severe acute respiratory syndrome) upon major asia-pacific service industries, notably airlines, hotels and retail trade. . economic and developmental implications of a series of unresolved security crises within asia and the middle east especially, including the apparently intractable palestinian question, the iraq crisis, and the problem of north korea's incipient nuclear capacity. these implications include a more problematic investment climate within affected nations and proximate regions. . the rapid rise (and even more dramatic contraction) of the so-called 'new economy', over the last years. the collapse of the dot.coms notwithstanding, however, information and telecommunications industries constitute essential features of all advanced economies, and are playing increasingly central developmental roles within the asia-pacific region (corey, ) . . the emergence of the 'urban cultural economy', underpinned by what allen scott describes as the convergence of culture and urban development, and comprising both cultural production and consumption as leading sectors within a growing number of cities and city-regions (scott, ) . cultural industries (including creative design industries, media and multimedia, and film, video and music production) represent increasingly important sectors of the urban economy, in cities such as los angeles, tokyo, kyoto, singapore, bangkok, and melbourne. . sharply divergent economic fortunes of the asia-pacific's major nation-states, including the remarkable growth of advanced industrial production and trade in china, the continuing japanese economic malaise, and slow growth in the american economy (the stagnation of american consumer markets has also seriously retarded exports from other asia-pacific nations.). . continuing processes of restructuring and transition among the advanced economies of east and southeast asia, including taiwan, south korea, and singapore, as well as in 'threshold' nics such as malaysia, thailand, and vietnam. to illustrate, an "important feature of asean economic development has been the growth of their services sector" (tongzon, : ) , as reflected in gdp and employment data. . new phases of development within the industrial structures and space-economies of asia-pacific city-regions, exemplified by processes of accelerated tertiarization, decentralization, and multinucleation among major chinese coastal city-regions (yeh and wu, ) , and by the emergence of 'new economy' clusters within inner city sites of cities such as tokyo, singapore, san francisco, and vancouver. . increasing awareness within the asia-pacific of ecological implications of accelerated development (and more particularly rapid industrialization), including resource depletion and overall environmental degradation, stimulating interest in principles of sustainable development. . exacerbation of urban social problems (increasing income disparities, social polarization, and community dislocation), both in rapidly growing states (notably china) and also in some lagging countries and regions within the asia-pacific. these social costs are discounted by some as inevitable outcomes of rapid economic growth, but there has also been evidence of interest in exploring possibilities for reducing social inequities, both in terms of new socio-political 'compromises' at national government levels (scott et al., ) , and also commitments to social planning as an integral feature of local government and administration. this illustrative listing of new development conditions inevitably masks quite highly differentiated experiences at the national, sub-national, and local levels, but may provide a backdrop to a new phase of experimentation in policy formulation and institutional innovation. clearly, these development conditions will influence new planning choices and directions across the full range of local and regional policy domains. in the aggregate, these conditions tend to 'stretch' local policy capacity and to place increasing pressure on urban planning systems, staff and resources. however, there may be promising opportunities for policy experimentation within the realm of the urban service sector, in light of the increasing centrality of service industries to trajectories of urban development, and the far-reaching implications of tertiarization for urban form and the built environment, the metropolitan space-economy, and the city's social structure (as well as derived demand for housing and transportation). in chapter we will explore some of the leading models of urban policy for service industry development within the broadly defined asia-pacific region. planning for new trajectories of services-led urban development as observed previously, urban planning and policy responses to tertiarization within the asia-pacific region include ambitious programmes which deploy service industries as instruments of development and transformation. a review of urban policy experiences over the last decade and a half discloses explicit associations between services (especially advanced, specialized and intermediate service industries) and plans for globalization, restructuring and modernization. while the mix of policy measures varies from place to place, these service industry programmes typically incorporate substantial public investments, inducements to attract private capital and the commitment of market players (foreign and domestic), adjustments to regulatory regimes, spatial planning elements, and sets of ancillary policies, notably in transportation and housing. the record of these ambitious (and even grandiose) policy initiatives includes some significant successes, in terms of the basic transformational aims (and business objectives of market actors), although the experience is also replete with examples of institutional conflicts and tensions. these include 'structural tensions' in some cases between local agencies mandated to vigorously promote growth and change, which tend to embrace narrowly economistic principles and objectives, on the one hand, and local planning departments which may prefer more holistic programmes, with broader, more inclusive public purposes. there may also be conflicts between central and local governments concerning policy preferences for service industries and economic development more generally. aside from these institutional tensions there are also growing concerns about social and environmental implications of rapid urban economic growth and transformational change. these include social costs such as community dislocation and social polarization, as well as environmental impacts which may include the destruction of heritage buildings within areas undergoing rapid change, encroachment of cities on adjacent agricultural and natural terrains, and the degradation of air and water quality within the regional biosphere. there are also examples of growing awareness of the financial and ecological costs of intense inter-city competition for investment, new service industries, and employment generation, which in some cases takes the form of a proliferation of facilities within extended metropolitan regions (as exemplified by airport development within the pearl river delta). these more problematic features of accelerated urban growth and transformation, coupled with the changing development conditions identified in the conclusion of chapter in britain this institutional tension at the local level is exemplified by the (sometimes conflictual) relationships between local 'regeneration' agencies mandated to promote new investment, industry, and job creation, and the local planning departments which perform a range of regulatory and management functions. similar tensions between local development agencies and municipal planning departments can be observed in west coast cities of north america, including vancouver. with respect to institutional tensions between local and central governments within the asia-pacific, we can cite the recurrent conflicts in development aspirations between the okinawa prefecture and tokyo ministries over the nature of okinawa's growth and change, exacerbated by structural problems of core-periphery asymmetry and dependency, as well as the increasingly problematic us armed forces bases on the principal island. , have stimulated new interest in planning innovation at the metropolitan and local government levels within the broadly defined asia-pacific region. while urban policies emphasizing transformational growth and change, underpinned by globalization and modernization aspirations, and by imperatives of competitive advantage, are still pervasive within the region, we can also discern significant interest in alternative (and perhaps more progressive) urban planning models. these include, for the purposes of illustration, experiments in sustainable urban development, community economic development (ced), and co-operative regional development. the purpose of this chapter then, is to depict the breadth of urban policy initiatives involving programmes for service industries, at the city-region and local levels, underscoring the dominance of transformational policies throughout much of the region, but disclosing as well interesting (and potentially significant) policy experimentation and innovation. while a comprehensive description of urban service industry approaches (and the programmatic details of these policies) is beyond the scope of this paper, it may at least be possible to structure a number of the leading models for comparative purposes. accordingly, table depicts six strategic policy models which deploy service industries as important instruments or modalities, together with some representative programme elements, underlying principles and values, and exemplary reference cases within the asia-pacific urban network or hierarchy. accordingly the framework of urban policy models depicted in table includes three ensembles associated with the dominant developmental paradigm of the latter period of the th century (associated with globalization aspirations, industrial restructuring, and modernization), and a set of three policy models which reflect current or emerging directions which seem to offer more progressive developmental possibilities. these latter three urban policy ensembles include policies for service industries which emphasize possibilities of co-operation with the broader regional setting, examples of initiatives which support the idea of the 'sustainable' city-region, and, finally, planning for the new urban cultural economy, acknowledging what allen scott describes as the strategic convergence between culture and urban development (scott, ) . what follows is a description and concise discussion of each of these defining urban policy models. over the past two decades both local and senior-level governments have deployed policies for certain service industries as key instruments of globalization (or internationalization) strategies within the asia-pacific region. objectives in this policy realm have included overcoming scale limitations of local markets and regional entrepôt roles (e.g. singapore and vancouver in the s); integrating regional and national economies within global markets, to attract foreign capital and promote modernization within the domestic economy (as in the case of certain chinese coastal cities since ); and pursuing strategic trade and co-operation partnerships with selected foreign cities (for example fukuoka since the early s). inter-city competition, concepts of competitive advantage, urban hierarchy; discounting of social costs (daniels, ) singapore (since mid- s); shanghai, osaka, fukuoka deregulation/privatization foreign direct investment urban mega-projects (after olds, ) service industries and 'postindustrial' trajectories pursuit of 'growth services' and propulsive intermediate service industries within context of industrial decline/obsolescence; acceptance of dislocation and displacement effects (hall, ) nagoya, hong kong, singapore land use policy change human capital investments targeted industry support programmes service industries and the 'new economy' assertive technocratic vision which privileges the future; idea of it as principal instrument of urban transformation and modernization; 're-imaging' of the city via policyinduced technological development (bunnell, ) kuala lumpur-putrajaya, singapore, vancouver support for r&d promotion of urban 'technopoles' spatial planning and land use policy service industries and the 'cooperative regional cluster' model acknowledgement of complementarity (as well as competition) among centres within extended metropolitan regions (emr's), after mcgee (douglass, ) hong kong/pearl river delta, sijori, san francisco-bay area region institutional co-ordination joint planning and marketing efforts spatial rationalization of new investment service industries and the 'sustainable city-region' model principles of social and environmental policy; idea of 'efficient and equitable' city-region; acknowledgement of sustainability as planning paradigm or framework (goldberg and hutton, ) sydney, vancouver, pearl river delta planning for suburban service industry subcentres services within 'compact' and 'complete' communities extensive designated 'green zones' service industries and the urban 'cultural economy' idea of strategic convergence between culture and urban development (scott, ) ; significance of creative industries and workforce (florida, ) los angeles, singapore, vancouver public support of the arts policy support for inner city clusters heritage planning promotion of the ' h' city we can identify a distinctive range of policy modalities that have been introduced to exploit the globalization potential of advanced, specialized service industries and institutions within the asia-pacific region. these have included: (a) building capacity in strategic urban transportation and communication, infrastructure and facilities, such as seaports, airports, and teleports; (b) promoting the export of specialized services (such as 'producer' and other intermediate services), in order to exploit local comparative advantage in services to replace diminished goods export capacity, to improve terms of trade, and to achieve greater scale economies within regional industries; (c) stimulating the globalization of cities in situ, as exemplified by the series of urbanmegaprojects (umps) within the region which have included important service industry elements, such as the pudong ump in shanghai (olds, ) , and the mm ump in yokohama, which tend to promote the inflation of local land markets, the increased presence of foreign firms and multinationals in the central areas, and the comprehensive re-imaging of the city; and (d) exploring the possibilities of mutual benefit through reciprocal, two-way trade in services (including educational and cultural services, as well as in business services) with designated cities as elements of international 'sister cities' or 'city partnerships', exemplified by fukuoka's 'global reach' programme (fukuoka municipal government, ) , and the city of vancouver's 'strategic cities' programme (city of vancouver, ). clearly there are important, substantive economic development and trade purposes associated with these globalization strategies, but there are also (explicit or implicit) reimaging aspirations in many cases. the classic example within the asia-pacific is the restoration of shanghai as a global centre of finance, corporate control, and business services, supported by assertive regional and central government policies and programmes, massive foreign investment, and the conscious engagement of elite international architects, planners, and developers in shanghai's accelerated transformation olds ( ) . other examples include yokohama's goal of escaping a constrained role as tokyo's 'shadow city' by means of the ambitious mm docklands scheme, as well as osaka's search for a larger international profile, to be furthered in part by the redevelopment of the cbd and the massive osaka -kansai international airport project. these urban globalization strategies have been centrepieces of local and regional development strategies for an increasing roster of asian-pacific cities over the past decade or so, with commensurate heavy commitments in local financial, policy, and human resources. in light of these major investments, a number of these globalization programmes have achieved a measure of success, in terms of accelerating growth, integrating cities within global markets, and other essentially economistic goals. however, there have also been significant social and environmental costs associated with these programmes, and high levels of local exposure to a variety of risks, as social and ecological values have (despite policy rhetoric to the contrary) been substantially discounted against the perceived benefits of accelerated globalization (see douglass ( ) for a treatment of the tokyo case study). the single-minded pursuit of transformational urban development through market integration, enhanced (or induced) comparative advantage in export service trade, and comprehensive local re-imaging has led to large-scale community displacement and dislocation (as in shanghai), high corporate and municipal financial exposure (yokohama's mm project, and tokyo's waterfront development), and inflation in local property markets (many instances throughout the region). these significant social and environmental costs tend to be associated with the more comprehensive, grandiose projects. correspondingly, more selective, smaller-scale or 'managed' internationalization programmes are likely to generate fewer such costs. again, examples of these more selective internationalization programmes would include the fukuoka experience, in which mutual benefit between urban communities represents an explicit aim; and the vancouver case, in which the city's internationalization programme in the s included both considerable stakeholder input, and measures to ameliorate social costs of accelerated urban globalization (hutton, ) . the development record of most cities within 'advanced' societies over the last three decades or so includes generally increasing shares of employment, gdp and exports accounted for by service industries. there have of course been debates about whether this trend toward the tertiarization of the urban labour force, output and trade represents a 'natural' process or progression, but what is incontestable is that some cities have endeavoured to accelerate the shift from basic manufacturing to services, especially specialized and intermediate service industries and employment. as noted briefly in preceding chapters, the asia-pacific region encompasses numerous case studies of this policy preference. central to the policy values underpinning urban programmes for restructuring which favour service industries and institutions is the (explicit or implicit) endorsement of the 'post-industrial thesis', first enunciated by the american sociologist daniel bell, which postulated a pronounced shift from goods to services production as a defining feature of advanced urban societies. (see table (a) and (b) for a more comprehensive set of urban tertiarization attributes). as kong chong ho has observed, cities have been obliged to respond to restructuring processes (ho, ) , including retraining programmes for displaced workers, and welfare programmes and transfer payments as well as policies to promote industrial restructuring as part of modernization strategies (hall, ) . in a number of cases, urban programmes of accelerated tertiarization have been undertaken within a context of urban-regional industrial decline or obsolescence. this has been observed within the japanese metropolitan system, where the 'hollowing out' of the national industrial economy has been deeply felt, in terms of factory closures (or relocation offshore) and protracted structural unemployment. for some of these cities, new service industries and associated labour cohorts, production and trade constitute a possible new urban development trajectory or 'vocation'. as noted earlier, too, urban development planning and programmes have been influenced by research which has established certain advanced services as urbanregional 'propulsive industries', based on associated productivity measures, inputoutput relations and sales and employment multipliers, export propensity, and skilled labour formation. here, the large-sample survey of export services undertaken by beyers et al. in the mid- s for the seattle-central puget sound economic development district (cpsedd) has been especially influential in providing an empirical justification for services-oriented metropolitan development strategies (beyers et al., ) , complemented by theoretical work undertaken by peter daniels, jean gottmann, and others. important case studies of accelerated tertiarization within the asia-pacific include singapore, hong kong, and nagoya. in the case of the former, a short but sharp recession in the mid- s stimulated a comprehensive policy research exercise in singapore, culminating in an important development policy shift favouring intermediate services with high export propensity (or potential). underpinning this defining policy shift was the work of a special subcommittee exploring the merits of manufacturing-versus services-led urban development and growth. the subcommittee concluded that advanced, specialized services enterprises "contribute about twice as much value-added as manufacturing firms" (clad, ) , and constituted a more promising growth sector than most forms of goods production. accordingly the government of singapore embarked upon a comprehensive programme to accelerate growth in specialized services in , including incentives for foreign investors, new expenditures in education and training, sweeping fiscal changes (including major tax cuts, and reductions in payroll taxes), service industry support programmes, and marketing and information strategies. in hong kong over the same period the colonial government was also engaged in policy support for an increasingly post-industrial economy and workforce. as observed by bruce taylor and reginald win-yang kwok, this accelerated tertiarization strategy comprised important policies for urban structure and land use, including major land reclamation in wanchai and causeway bay to accommodate the expansion of hong kong's cbd, the ongoing industrial new town programme in the new territories to enable relocations from the central district and kowloon, and new investments in rapid transit (taylor and kwok, ) . as a measure of the effectiveness of this programme (coupled with the influence of market-driven change), services now account for over fourfifths of hong kong's labour force, and there is more employment in intermediate (or business) services than in consumer services (asian development bank, ) . in both the hong kong and singapore examples it can be argued that these policy shifts essentially reinforced (or accelerated) post-industrial urban vocations already in progress. however, the experience of certain japanese cities offers a quite different set of policy conditions and experiences. david edgington has written extensively about the role of industrial restructuring policies for the important nagoya -chukyo region, a key part of japan's industrial heartland. he depicts schematically a progression of new industrial vocations for chukyo over the second half of the th century, which includes (first) a mix of heavy industry (aircraft production and munitions) up to the s; secondly, a shift to heavy industries (steel and petrochemicals) and consumer products over the s; followed by strong growth in auto production (toyota), heavy engineering, and light industries during the s and s. however, the last decade in the nagoya -chukyo region has seen new local (prefectural and municipal) policies and planning in support of a 'new vocation' of knowledge-intensive industries, including aerospace, advanced electronics, new ceramic materials, information technology, biotechnology, and fashion design and production (edgington, : ) . this new vocation builds upon the nagoya -chukyo region's embedded excellence in advanced industrial production, but with greatly enhanced services, design, and technology inputs to production. here, the role of local government (as distinct from the well-known national government industrial support programmes) has emphasized "strengthening regional culture, design and general amenity upgrading for chukyo" as an "important part of regional restructuring" (edgington, : ) . the nagoya -chukyo experience represents an example of complementarity between central and local governments in promoting industrial restructuring at the regional level. the emergence of a 'new economy' characterized by propulsive roles for advanced information and communications technologies (ict), although to be sure a contested concept, has stimulated considerable interest among governments and policy communities within the asia-pacific. for a number of jurisdictions, policies for supporting ict are seen as means of rejuvenating urban and regional industrial production sectors (notably in japan), while in others investments in ict, implemented by spatial planning, land use, and human capital planning programmes, provide a means of 'leapfrogging' stages of economic development (malaysia). technology-driven development has also been central to new urban development experiments, as in the case of the tsukuba science city in japan. as a planning preference, support for accelerated ict development and other new economy activity can be seen as the endorsement of an assertive technocratic vision of urban and regional development, as observed by manuel castells in his discussion of 'the informational city' (castells, ; scott, ) . ict is deployed as a key instrument of urban transformation and modernization, with both 'substantive' effects (higher productivity and value-added production; business start-ups and labour formation) and 'symbolic' outcomes (re-imaging of local/regional societies and economies), although there are to be sure concomitant costs and dislocations (bunnell, ) . within the asia-pacific, we observe a number of instructive examples of ict-driven development strategies at the urban and regional levels. there are of course the globalscale advanced-technology regional complexes of silicon valley and orange county in california, seen as essentially 'spontaneous' (i.e. market-driven) enterprises, although the role of state-supported universities and other public agencies should be acknowledged. then there are the large r&d formations (applied research, prototype development) within japan, largely funded by major japanese multinationals and industrial conglomerates, but also influenced significantly by central government ministries and agencies. these massive american and japanese r&d complexes have of course been established for many years, and represent in some ways an earlier model of technologydriven spatial development linked to large industrial corporations. a number of other, newer examples of new economy exhibit in some respects different attributes, including larger roles for government and public agencies, more emphasis on integrated service industry engagement (including creative and design services, as well as financial, business, and communications services), and contrasts in scale. the range of examples in this more recent cohort of technology-driven enterprises varies from the extensive putrajaya -cyberjaya project in malaysia, described by kenneth corey as a defining project of malaysia's national economic development programme (corey, ) , to a series of inner city new economy experiments within a large and growing number of cities, including singapore and vancouver. these recent inner city new economy projects are clearly differentiated from the 'first generation' urban and regional technopoles in a number of ways, not only in the matter of scale, location, and provenance, but also in the mix of industries and activities. key to these new inner city formations is the concept of the metropolitan core as a special, in some ways unique, 'innovative milieu', providing advantages of socio-cultural, as well as economic, agglomeration, to constituent firms. there is also, as noted, a stronger service industry element, as in both the singapore and vancouver examples the explicit strategy involves fostering developmental synergies between technology (especially ict), culture (in the form of creative and design service industries), and 'place', as expressed in the innovative milieu of the inner city. these inner city new economy sites are characterized by intense interaction (formal and informal), deployment of both 'placed-based' and 'cyber-based' production networks, and a distinctive demography, emphasizing mostly younger creative and technological workers and entrepreneurs. . . . service industries and the 'co-operative regional cluster' model as is well known, the development experience of the asia-pacific region over the past four decades has been characterized in large part by prevailing attitudes of competition for shares of investment, trade, and new employment formation, between (and among) nationstates, regions, and even cities. this animating sense of competition between jurisdictions has at times been exacerbated by contrasts in stages of development, by ideological factors, and more forcefully by the pressures of accelerating globalization. development policy postures have therefore in many cases been influenced by a perception of regional development opportunities as a 'zero-sum' process of clear 'winners' and 'losers', leading to an emphasis on nurturing localized positions of competitive advantage (douglass, ) . assumptions of development as an essentially competitive process are of course still powerful influences on policy formation within the region, but there are also significant (and likely expanding) movements toward inter-jurisdictional co-operation, shaped by progressive ideas of reciprocal trade benefits, knowledge-sharing, and developmental complementarity. this is seen at the broadest spatial scale in the establishment of the apec grouping, an association which endeavours to promote liberalized trade and cooperative development within the pacific sphere (as well as providing a counterweight to other continental-scale bodies, notably the eu and the nafta states). at the regional level asean provides a forum for dialogue and trade co-operation among the states of southeast asia. then there is a steady proliferation of less formal regional co-operative associations, including a number of such entities in northeast asia (kim, ) , and joint international development projects, exemplified by the sijori (singapore-johore-riau) growth triangle in southeast asia, and the tumen river area development project in northeast asia (marton et al., ) . many of these developmental arrangements are replete with significant institutional asymmetries and tensions, but they may suggest the possibility of greater tendencies toward regional co-operation, perhaps working over the longer term to approach the levels of engagement and co-operative commitment of the 'associative regions ' (mcgee et al., ) of the eu. more specifically, it may be possible to envisage regional co-operation arrangements based in part on the functional complementarities of regionalized service industry clusters and corridors, described in chapter . as will be recalled, it is possible to identify at least conceptually ten major service clusters or corridors within the asia-pacific, each containing multiple cities and important ensembles of specialized service industries, institutions, and facilities. as in other co-operative ventures at the regional scale, there is an initial need for governments, business interest, and other stakeholders to recognize and acknowledge possibilities of complementarity and mutual benefit associated with these complexes of specialized service industries. in the absence of joint governance, common taxation regimes, and revenue sharing (in addition to issues of (for example) labour market standards and environmental norms) these co-operative regional arrangements may be problematic, but the difficulties may not be insuperable. indeed, the nature of service industry specialization may in many cases lead itself to a broader recognition of co-operative possibilities, even in cases where inter-jurisdictional competition has been the prevailing spirit. co-ordination of investments, operations, and marketing for strategic transportation and communication facilities, for example, can enhance the comprehensiveness of 'gateway' functions for an extended regional corridor or cluster. co-operative planning and programmes for regional tourism initiatives, involving a diverse range of assets, amenities, and hosting infrastructure (e.g. hotels and convention centres) which offer greater potential attraction to visitors than the individual, localized sites within the region, can yield mutual benefits. potentially these principles of co-operation and co-ordination could apply in other important service sectors and industries, for example higher education and specialized health case, acknowledging the advantages of 'packaging' services and expertise offered by diverse firms and institutions within extended regional territories. through greater levels of co-ordination and planning of specialized service functions, regions can achieve stronger competitive positions within international and global markets. within the asia-pacific, the hong kong -pearl river delta offers a particularly instructive case study. following the economic reforms introduced by deng xiao-ping in , the pearl delta experienced extraordinary levels of growth in investment, business start-ups, employment formation and physical development. much of this growth was in the goods production sector, especially light manufacturing, but (as observed in chapter ) the prd also experienced rapid expansion in services. however, there was a chaotic pattern to much of this development, as evidenced in the growth of the shenzen special economic zone (sez), and in the proliferation of new airports within the delta. this period of rapid growth was also characterized by an almost 'free for all' competitiveness among the urban centres of the region. although the prd has experienced high levels of growth over the past two decades within an essentially competitive context, there is significant evidence of co-operation and co-ordination in recent years, especially since the establishment of the hong kong special administrative region (sar) following the reversion of the former crown colony to china in . these efforts to pursue co-operation in economic development have been documented in a recent book edited by anthony gar-on yeh et al. ( ) , titled building a competitive pearl river delta region: co-operation, co-ordination, and planning. to some extent, of course, this desire to achieve co-ordination is related to the need to avoid wasteful, inefficient duplication of functions, to preserve resources, and to rationalize spatial planning in a congested, high growth region. there is also a need to 'manage' competition between the two major centres of the region, hong kong and guangzhou (kwok and ames, ; cheung, ) . however, an important principle underpinning the increasing levels of co-operation within this administratively fragmented and complex region is the exigency of responding to pressures (and opportunities) of globalization. in this respect, the pearl river delta contains both a dense pattern of manufacturing and industrial production, as well as concentrations of specialized service industries, institutions, and functions, including banking and finance, seaports, airports, higher education, cultural and creative services, and public administration. these specialized services represent the best prospects for future growth and development in the region, and greater co-operation and co-ordination of these key services can significantly strengthen the prd's competitive position within east asia and global markets. there is considerable potential for co-operation in the planning and development of other major regional service clusters and corridors within the asia-pacific. the basic idea is to explore means of managing competition between service industries and installations within regional settings, while capitalizing on functional complementarities to achieve stronger international competitiveness. much of the regional co-operation within the region over the past years has been undertaken for areas specializing in manufacturing and industry, as in the sijori and tumen river area projects cited earlier. however, given the momentum of tertiarization within the asia-pacific, and the strategic global functions performed by certain service industries, institutions, and firms, co-operative management and co-ordination of regional service clusters present especially promising possibilities for future urban and regional development within the asia-pacific sphere. there is a need to strengthen regional governance and administration as a pre-condition, however, as the lack of effective regional institutions represents a major constraint. as an example, the association of bay area governments (abag) in the san francisco bay region provides a forum for inter-jurisdictional dialogue and a certain amount of coordination, but lacks the capacity to promote effective regional development co-operation. in addition to the transformational roles described earlier, service industries are increasingly deployed as key elements of spatial and land use planning within the asia-pacific, including a new generation of regional plans influenced by principles of sustainable development. although the specific forms of these new city-region plans of course vary from place to place, we can discern features of three important traditions of spatial (or physical) planning, as follows: (a) elements of spatial planning derived from the classic 'containment' model of planning for metropolitan city-regions, incorporating stringent development control on commercial development in the central city, the establishment of green belts or zones, and the designation and development of new (or expanding) towns on the regional periphery, as seen in the post-war planning of london and the south east region of england (hall et al., ) , and updated in the sequence of 'structure plans' for english counties in the s; (b) attributes of 'new urbanism' planning models (and related concepts) introduced in the s, which included the ideas of 'compact' (as opposed to dispersed) and 'complete' (in contrast to dormitory) communities within city-regions, an emphasis on transit-oriented development (tod) (and the increased management of automobile traffic), and a preference for 'traditional' (or 'neo-traditional') housing styles and vernaculars; and (c) principles of 'sustainability' (or 'sustainable development'), which have increasingly influenced the planning of city-regions (as well as 'natural' or 'resource regions') since the rio 'earth summit' of , and which encompass ideas of ecological preservation, biodiversity, the integrity of ecological systems, and the need to manage (and eventually reduce) the human 'ecological footprint'; i.e. the impress of human activity on the world's natural resources and biosphere. in the urban context, sustainability principles can also be applied to the city-region's economy, culture, and social 'capital'. the extent to which principles derived from these major models of urban and regional planning is dependent not only on considerations of urban scale, environmental setting, industrial structure, and growth rates, but also on the structure of urban governance, the nature of political control, characteristics of the local planning system and policy agencies, the quality of leadership, and other institutional factors. at the broadest level, however, there is a kind of structural tension associated with contemporary spatial planning for metropolitan regions, between the need for flexibility to accommodate changing locational demands of business and industry (including the so-called 'new economy' activities) and new residential preferences, on the one hand, and the imperative of deploying policies to impose a measure of order on the growth of human settlements, in accordance with ecological and social values. service industries have been assigned roles within each of the three principal spatial planning ensembles cited earlier, although these have been demonstrably subject to change. within the 'first-generation' containment models growth management, development control, and the accommodation of population growth by means of supporting designated regional centres were dominant aims, and services (including offices) were addressed primarily by a suite of regulatory policies in the early post-war programmes, as described in chapter (goddard, ) . however, a 'second generation' of regional plans in the s, derived from the containment model in britain, canada, and numerous other states, included the idea of rtcs (or commercial subcentres), within which office development and firms were assigned important roles. these new suburban or regional subcentres were intended to attract new office development, not only to manage development pressure on the cbd, but also to provide more employment opportunities in areas of rapid population and labour force growth, thereby also reducing commuting pressures. within the rubric of new urbanism, offices and other service industries were also seen as important spatial planning elements. to illustrate, concentrations of relatively high-density service development can enhance prospects for the formation of 'compact' (as opposed to dispersed and low-density) communities, while the inclusion of service functions and employment were central to the implementation of 'complete community' strategies. finally, although sustainable development has emphasized the primacy of ecological values and environmental planning, service industries have a number of important implications for sustainability planning. the status of services as the most rapidly growing elements of many urban economies has ramifications for resource consumption (including land), while the mismatch between service employment concentrations and residential development exacerbates the metropolitan commuting and traffic congestion problems, impacting regional air quality. at the same time, the fortunes of the service sector and its constituent industries also have a clear connection to the socio-economic sustainability of the metropolis, especially in light of contractions in fordist manufacturing. . . . . experiences within the asia-pacific. the highly differentiated stages of development and local institutional arrangements among asia-pacific city-regions offer a rich array of experiences in policies for service industries within spatial plans. these include a substantial sampling of metropolitan cities which have deployed containment strategies or 'structure planning' concepts, incorporating the designation of secondary office-commercial centres or subcentres. this has been especially the case in jurisdictions strongly influenced by british planning models, notably australia, canada, singapore, and hong kong, but resonances of the containment model and its defining features (green belts, new residential communities, and designated service industry subcentres) are also discernible in japanese city-regions. we can also identify aspects of the new urbanism and sustainability models in a growing number of city-region plans, although in most asian cities the experience is in incipient stages. a (necessarily concise) selection of reference cases follows. as observed earlier, the location and development of service industries within guangzhou and the pearl river delta (as well as other fast-growing chinese cityregions) has become a major spatial planning issue over the past decade, and underscores the tensions between accommodating growth and the pursuit of sustainable development. within the guangzhou city-region, the combination of liberalized development policies, a greatly expanded role for the market, and high levels of growth have reshaped urban structure and land use over the last years, as disclosed in a recent empirical study by fulong wu and anthony gar-on yeh. during this period, there has been substantial redevelopment within guangzhou's central city, but its overall spatial reconfiguration "is changing from a compact city to a dispersed metropolis as a result of reforms which introduced land values and markets to its urban areas" (wu and yeh, : ) . a measure of this dispersal and sprawl consists of industrial estates, but new service industries and commercial development, driven in large part by foreign investors, also play a role in this process. as wu and yeh conclude, "[the] conflict between urban spatial restructuring and development control is inevitable" (wu and yeh, : ) in high-growth cities characterized by the decline of central planning and inadequate local planning powers. michael leaf goes even further, asserting that in these dynamic chinese cities, "the practice of urban planning may have passed from irrelevance under the command economy of the past to gross ineffectiveness in the socialist market economy of today" (leaf, : ) . moreover, local planning systems in at least some chinese cities are developing more sophisticated planning styles, and an increasing number of planning professionals are engaged in exploring sustainability principles, so it may be that the next generation of city-region plans will incorporate stronger elements of sustainable development. other reference cases within the asia-pacific provide quite different experiences of spatial planning and contrasting perceptions of the role of services in regional sustainable development. the evolution of spatial planning in metropolitan vancouver represents a sequence of new roles for service industries, from 'containment' to sustainable development. in vancouver's first regional plan, the livable region region - (approved , the classic elements of the post-war containment spatial plan were all present, including green zones (incorporating special protection for agricultural land, an emphasis on public transit, and the designation of four regional (suburban) town centres, each of which was to attract one million square feet of office space over the term of the plan. at the same time, the regional plan proposed strong development control policies for the cbd, both to ameliorate commuting and to enhance office development prospects for the rtcs (hutton and davis, ) . two decades later, a new livable region strategic plan (lrsp) ( ) affirmed the multinucleation strategy of the earlier plan, and indeed added several new rtcs, but also introduced policies for 'compact' and 'complete' community formation, influenced by the new urbanism spirit. service industries were allocated important roles in the lrsp, as the concentration of new offices in the (now eight) rtcs would support the principle of compact settlement forms, while a more diversified range of both intermediate and final demand services (including commercial, retail, and educational services) would promote the formation of complete communities within the city-region, integrating important service functions and local employment opportunities with residential development. more recently, a new public process has been initiated by the greater vancouver regional district, the regional planning agency for metropolitan vancouver, with a view to more vigorously asserting sustainability values and principles in the lrsp. this initiative includes the possibility of strengthening the (already-substantial) ecological conservation measures of the regional plan, but there is also a new emphasis on the importance of economic sustainability as a critical planning priority. in this new planning consultation process, key informants, stakeholders, and the general public are invited to propose new ideas for enhancing the economic sustainability of the region, including the spatial planning implications of new service industry development. these include the cbd (now seen as a unique and valuable regional assets rather than principally a generator of negative externalities, as interpreted in the metropolitan plan), the eight designated rtcs, the port of vancouver, vancouver international airport, the region's universities and colleges, and a number of 'new economy' sites, both in the suburbs and in the metropolitan core. spatial planning measures for service industries that promote multinucleation within metropolitan strategies can be seen as supporting economic sustainability (nurturing of high growth service industries, building capacity for industrial transition, enhancing regional economic resilience) as well as ecological sustainability (conservation of scarce urban land resources, mitigation of commuting-related air pollution). agglomeration of advanced service industries promotes the 'cluster-driven' process of advanced urban development, as seen in the vancouver example described earlier. other important examples within the asia-pacific include the global-scale concentration of advanced-technology service industries clustered in redmond, washington, within the metropolitan seattle-king county city-region, and the recent development of sydney's north shore high-tech corridor. this corridor has seen a functional and spatial evolution over the past four decades, initiated in the s by a secondary cbd in north sydney, at the north end of the sydney harbour bridge, followed by the establishment of a major regional shopping centre in the s, and the development of macquarie university on a nearby site (o'connor et al., ) . with these activities serving as a base, the last two decades have seen the dramatic growth of new technology-based industries and advanced services: the north shore corridor is anchored by microsoft corporation at one end, and cable and wireless optics at the other, with five commercial clusters situated between these two major poles (o'connor et al., ) . by the mid- s, employment within the north shore corridor exceeded , included jobs situated within member companies of the australian information industry association (o'connor et al., ) . sheehan quotes a property consultant as describing the north shore corridor as "technology land, but it's not physical production, it's brain power and computer power, biased toward sales, service and management rather than research, development and production" (sheehan ( : ) , as quoted in o' connor et al. ( : - ) ). clearly, on this evidence, market players (investors, entrepreneurs, and professionals) have been central to the development of sydney's north shore corridor, but government and public agencies have played leading roles in terms of regional spatial planning, municipal land use policy, and in tertiary education investment. the sydney north shore corridor experience also vividly depicts the functional evolution of service industry clusters over time, in this case from a secondary office and shopping centre to an incipient high-technology site, and finally to a large-scale 'new economy' site of national significance, including advanced-technology industries and specialized service functions. urban centres within the asia-pacific region, as elsewhere, have played important roles as repositories of signifying local, regional, and national cultures, as exemplified by cities such as beijing, kyoto, and hanoi, and many others. these important cultural roles are manifested in (for example) language and dialect, in museums, galleries and archives, in institutions of higher learning, in the built environment, and in social organizations and agencies. these cultural activities have economic as well as social value, as expressed in direct employment generation and incomes, tourism receipts, and the capital value of infrastructure, including heritage buildings. these traditional cultural roles continue to be important (albeit recurrently renegotiated by political acts and social experiences, and subject to new cognitive filters), but are now significantly augmented by fresh processes of reproduction, innovation, and economic development, both in the market and public domains. over the last decade or so, we have witnessed dramatic growth in a range of creative, design-based and 'new cultural' industries. as allen scott has observed in a well-known treatment of 'the cultural economy of cities', "[a]s we enter the st century, a very marked convergence between the spheres of cultural and economic development seems to be occurring" (scott, : ) . within cities, the expansion of this new cultural sector includes film, video and music production, graphic artists, industrial design, fashion design, and architecture, as well as 'hybridized' firms which combine creative and technological outputs toward products (goods and services) imbued with high design content, including multimedia and 'new media' activities, internet graphics and imaging, and software design. again to reference scott, "an ever-widening range of economic activity is concerned with producing and marketing goods and services that are infused in one way or another with broadly aesthetic or semiotic attributes" (scott, : ) . creativity is an essential element of the city's role as centre of innovation, in cultural, industrial, and intellectual realms (hall, ) . within the broadly defined asia-pacific region we can readily identify some leading exemplars of this 'new urban cultural economy', such as los angeles (film production and post-production, music, and media), tokyo (media and communications, architecture, design-based industries), seattle (software design, music production), hong kong (music, creative and design-based industries, media and communications), singapore (advertising and corporate branding, multimedia), melbourne (creative and design-based industries), and vancouver (graphic design and multimedia). the rapid expansion of these important new industries can be seen as the most recent development phase in the continuing evolution of the urban service economy, and the enduring competitive advantage of cities for specialized cultural production, as well as the reassertion of production activity in the inner city districts of some urban areas. moreover, these new forms of specialized cultural services production are characterized by a distinctive interface with consumer markets, as many of these industries supply what scott terms 'cultural products' (scott, : ) which influence public tastes and preferences, and are concerned with differentiating consumer market segments. the 'new cultural economy' represents a leading-edge urban policy area. within the mature urban societies of the atlantic core, there is a significant record of policy innovation. for example, within the eu, there are numerous programmes for both national and local governments to support cultural industries, including the annual designation of 'european cultural cities'. at the national level, the british government has produced detailed inventories of cultural industries, including employment, sales, and exports, as well as policy guidance for local authorities. in north america richard florida has written about the crucial importance of the 'creative class' of service workers for advanced urban economies, and has emphasized the need for progressive policies (liberal immigration policies, generous public support of the arts) to attract and nurture this creative workforce (florida, ) . within the asia-pacific, the new cultural economy should emerge as an increasingly important component of service industry strategies and more comprehensive economic development programmes. in singapore, the tourism board is active in promoting activities which intersect the new economy (technology-intensive industries) and the new cultural economy, including internet design firms, advanced design, and other creative services, concentrated within designated sites in chinatown, just west of singapore's cbd. as another example, far east properties has entered into an agreement with the government of canada, nortel networks, and the eu to sponsor a new business centre in another area of traditional chinese shop houses, just east of cross street, demonstrating again the possibilities of co-operative development in the advanced service economy. the refurbishing and subsequent 'recolonization' of these important heritage districts suggests that culture and social memory can be reconciled at one level with economic innovation, although there are of course sublimated tensions in these processes of transition and appropriation (see yeoh and kong, ( ) for insightful treatments of these issues). west coast cities in north america are also active in promoting the new cultural economy sector. los angeles and san francisco have agencies which promote new activity including these new cultural economy industries. in vancouver, the municipal government has undertaken comprehensive land use and rezoning to facilitate the transformation of a large ( ha) inner city site from traditional industry, warehousing and industry to new industries which interface with the technology and cultural sectors. this project includes a new campus (great northern way campus) comprising units of four vancouver-area universities and colleges, which has been established both to stimulate industrial innovation in the larger site, and also to encourage synergies between design-based and technology-based industries. there is also support for cultural and creative service industries among certain chinese cities. as observed earlier beijing's current plan strongly endorses the city's traditional cultural role, but there is also significant innovation in contemporary art and creative industries among beijing's universities and art schools (fackler, ) . in shenzen, a new three-year study of the city's dynamic cultural industries will include empirical research on clustering, linkage patterns (both place-and web-based), and the discourse of cultural landscapes, both to enlarge scholarly appreciation of these industries, and to inform policy (li, , personal communication) . on the other hand, the city of shanghai is demolishing the warehouses along suzhou creek which have provided a distinctive milieu for artists, artisans, and other creative workers. this eradication of shanghai's artist-loft district has been criticized as inimical to the fostering of cultural industries which complement the commercial functions of world cities, and to the emergence of an important 'spontaneous' (as distinct from induced) creative services cluster. lu yongyi, a professor urban planning at tongji university, has asserted that "[i]t will be too late when they realize these ruined communities were things of value that can never be rebuilt" (fackler, ) . by way of contrast, the residential high-rise towers which will replace the suzhou creek warehouse district, while meeting to be sure social needs, are replicated throughout the city, and could have been accommodated elsewhere in the comprehensive redevelopment of shanghai. finally, an increasing number of cities are exploring the ' h city concept' as a means of supporting the lifestyles of workers engaged in creative and 'hybridized' designtechnology enterprises. research has indicated that many of these professionals, artists, and entrepreneurs have irregular working hours, and are attracted by the h urban amenities of restaurants, night clubs, and all-night 'raves', as well as alternative recreations, such as skateboarding. these all-night activities do create tensions in residential areas within the inner city. here, there are possibilities for effectively integrating social planning, cultural programmes, and advanced service industry policies to nurture the development of these important new cultural and hybridized industries which constitute ascendant features of the st century inner city among advanced urban societies. conclusion: an agenda for scholarly investigation the purpose of this exploratory paper has been to establish tertiarization as an increasingly important process of urban development within the asia-pacific. the growth of advanced service industries will be crucial to the development of asia-pacific city-regions (and indeed to national economic progress) over the first decades of the new century. more particularly, advanced, specialized service industries will be central to employment and human capital formation, to the expansion of the urban middle class, to the more efficient operation of advanced industrial production systems and trade networks, and both to urban competitive advantage and the socio-economic sustainability of asia-pacific cities. reinforcing this latter point, many of the region's large industrial metropoles will begin to 'shed' manufacturing employment (as experienced in the wrenching deindustrialization of mature atlantic city regions, and in the 'hollowing out' of japanese manufacturing capacity), and will need services growth to partially offset these contractions. at the same time, growth in advanced service industries and employment will require greater public policy commitments, not only in the areas of infrastructure and supporting systems, and in land use policies, but also in education and training. here, we can return to an earlier comparative theme addressed in this paper, by acknowledging that effective policies for services (incorporating developmental as well as regulatory elements) have been seen as lacking in the old atlantic core coffey, ) , despite a relatively early experience of growth in advanced services within the region as a whole. the cities of the asia-pacific (and their respective central and regional governments) will need to develop more innovative policy approaches toward service industries over the next decade and beyond, reflecting the increasing significance of advanced services for economic transition and modernization. moreover, it must be acknowledged that policy selection in this sphere entails value choices (and conflicts). the facilitation of advanced services growth can, as we have seen in a number of asia-pacific cities, entail the dislocation of traditional industries, informal services, and residential populations. a balance must be struck between the imperatives of economic modernization and the claims of social justice, as well as respect for diversity and pluralism. a progressive urban planning posture should support the preservation of informal services and historic city districts, both of which sustain the authenticity of local identity, while at the same time promoting the intermediate, technology-based, creative and other specialized services essential to development. the idea of sustainable development, which has been articulated in some urban strategic plans within the region (at least at a rhetorical level), may present a progressive planning framework for integrating social, economic, and ecological values. recent research has disclosed that there may in fact be significant policy complements intersecting urban sustainability and competitive advantage, including policies for compact urban structure and land use, efficient transportation and transit, and education investments (goldberg and hutton, ) , which may inter alia support advanced service industry development, as well as enhancing social welfare and ecological sustainability. to some extent the expansion of service industries within the asia-pacific has assumed basic features of the earlier urban tertiarization experience within the mature regions of the atlantic core, but in other respects has been quite distinctive. these contrasts can be attributed in part to different models of intermediate services production and exchange, to the special roles of government policy in promoting accelerated services growth, and to the marked disparities in overall development at national and regional scales within the asia-pacific. these contrasts were identified and incorporated in our provisional typology of urban service specialization. the differentiated growth rates and levels of specialization in advanced services decisively influences urban hierarchy within the region, as well as patterns of services trade and exchange, and global city-region status (rimmer, ) . indeed, one of the salient issues for the future will be the extent to which full globalization processes may override established regional service markets, for example in finance, property and real estate, among others. the specialized service centres and corridors described earlier may emerge as platforms for the globalization of services produced within the asia-pacific, as well as engines of development within the region. the narrative suggests a mandate for scholarly inquiry into the growth and development of service industries within the broadly defined pacific realm, derived from attributes of the tertiarization experience which include ( ) relatively high growth rates of service industries and employment in an expanding number of pacific societies over the past decade or so; ( ) the larger developmental implications of rapid tertiarization, whether viewed as an important extension of industrialization, or as essentially a new phase of socio-economic development; ( ) the more specific consequences of rapid services growth for urban (and more categorically metropolitan) areas, and especially the role of tertiarization in processes of urban transition and transformation; ( ) the distinctive interface between public policy and market forces in the acceleration of service industry growth in many cities and regions of the asia-pacific; and ( ) the more problematic outcomes and impacts of service industry development within the pacific new core, including displacement and polarization impacts, exacerbation of globalization pressures on existing industries and local communities, and the special problems presented by the larger economic crises within east and southeast asia in particular, a phenomenon which has had serious consequences for the service industries of the region. no doubt other themes could be elucidated (beyers, ) , but even this necessarily selective inventory of strategic considerations presents a rich, stimulating and potentially consequential agenda for scholarly research. in addition to these empirical problems and policy issues, there are important theoretical questions to be addressed, associated with the role of tertiarization processes in the structure, growth and transformation of city-regions within the asia-pacific. there is a need to reconsider urban models embedded within the industrialization paradigm, in order to accommodate the increasing influence of service industries in the development of urban regions within the pacific realm. these theoretical exercises will naturally acknowledge the centrality of industrial trends and economic factors, but will ideally transcend narrow economistic parameters to consider both the social implications of services growth, as well as the socio-cultural basis of advanced tertiarization, following the lead of progressive urban scholarship both in the atlantic and pacific spheres (moulaert and gallouj, ; kim et al., ) . more specifically, there is a clear need for conceptualization of trajectories of service sector development within the asia-pacific which embody experiences of differentiation and exceptionalism that abound within the region, as well as more widely observed features. beyond this important theoretical terrain, urban scholarship should address the relationships between the location of service industries and the reconfiguration of regional structure and the metropolitan space-economy. innovative new research in this realm includes larissa muller's work on business services in southeast asia, incorporating commentary on opportunities 'for localizing international investment' within the region (muller, ) . at the larger metropolitan scale, these models would position services as decisive influences on multinucleation, and would encompass spatial linkages between advanced services and manufacturing enterprises in regional production systems. at a more localized level, new urban spatial models should incorporate the emergence of emerging clusters of specialized services within reconstructed precincts of the inner city, including constituent ensembles of integrated services production networks. this should include research on the 'new economy' industries and cultural and creative activities which comprise the most recent phase of urban service industry development. finally, we can identify rich potential for socio-economic models of urban tertiarization that depict the role of services in social change within the region. there is an opportunity to investigate the hypothesis of a 'new middle class' (ley, ) as an ascendant social constituency among those asia-pacific cities which have experienced rapid growth in services. another research frontier concerns the new social divisions of service labour within asia-pacific cities, reflecting the convergence of culture, technology and urban milieu, observed in a growing number of new service production spaces within the region. then there is the overriding influence of global processes on the occupational and social structures of urban communities, including the role of mncs, the changing international division of production labour, innovation in telecommunications, and international migration. the extent to which these three powerful sets of forces-an ascendant new middle class of elite service workers, emerging social divisions of service labour, and globalization processes-influence social change and exacerbate social polarization tendencies within asia-pacific cities will surely assume greater theoretical and normative importance over the next decade and beyond. australian cultural diversity and export growth, office of multicultural affairs, canberra. asian development bank social transformations in the global city: singapore the coming of the post-industrial society services and the new economy: elements of a research agenda the service economy: export of services in the central puget sound region multimedia utopia? a geographical critique of high tech development in malaysia's supercorridor tropes of transboundary economic regions 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changing relationship with china: a speculative essay services in asia and the pacific: selected papers, united nations asean-eec trade in services corridors: a theory of urban system urban spatial structure in a transitional economy: the case of guangzhou development of land use and urban planning of guangzhou, centre for urban and regional studies bangkok's restaurant sector: gender, employment and consumption shanghai: transformation and modernization under china's open policy building a competitive pearl river delta region: cooperation, coordination, planning portraits of places: history, community and identity in singapore changing southeast asian cities: urbanization and the environment in international perspective the culture of cities sources for this project included extensive site visits and field trips to cities within the asia-pacific; communication with numerous colleagues, and key informants; participation in conferences and special workshops; and a review of several distinct literature domains, including the services research literature, asian urban studies, and the urban change and transformation scholarship. visits to chinese and southeast asian cities were undertaken as part of a much larger asian urban research project managed by the ubc centre for human settlements, supported by the canadian international development agency (cida centre of excellence grant # -s ). this study includes references to research undertaken by colleagues within partner institutions in asia, as well as theses produced by ubc graduate students supported by this cida grant. site visits and study tours of japanese cities were enabled by grants from the japan foundation, the japanese ministry of education, and the ubc hampton research fund. fieldwork in san francisco was supported in part by a grant from the ubc vice-president's (research) discretionary fund. an exploratory workshop on 'service industries and new trajectories of urban development within the asia-pacific', involving many of the leading international scholars in service industry scholarship and in asian urban studies was convened at the university of british columbia in march, , generously supported by the peter wall institute for advanced studies, ubc. this workshop significantly contributed to new knowledge on the role of service industries in processes of urban change within the asia-pacific, substantially informed this current paper, and generated manuscripts to be included in a new book to be co-edited by peter daniels (university of birmingham), kong chong ho (national university of singapore), and me.i also want to acknowledge the generosity of the centre for advanced studies at the national university of singapore in making possible my sojourn as visiting scholar in july of . this enabled me to liaise with (new and existing) colleagues, to conduct fieldwork, and to present a selection of findings to a cas colloquium. in particular i would like to express my appreciation to brenda yeoh, k.c. ho, peggy teo, and kris olds of cas (the latter now at the department of geography, university of wisconsin at madison), and to henry yeung of the nus department of geography.finally, i want to acknowledge the essential contributions of ubc colleagues. michael leaf (director, centre for southeast asian research, and faculty associate at chs) and david edgington (director, centre for japanese research, and associate professor in the department of geography) have generously contributed many expert insights on development planning issues in china, southeast asia, and japan. i am very grateful indeed for the administrative support of ms karen zeller, and the unfailingly professional and patient assistance of ms sharon kong in the preparation of this manuscript; for the high levels of technical assistance provided by ms christine evans; and for the excellent cartographic services of mr eric leinberger of the ubc department of geography. key: cord- -z c thl authors: jiricka-pürrer, alexandra; brandenburg, christiane; pröbstl-haider, ulrike title: city tourism pre- and post-covid- pandemic – messages to take home for climate change adaptation and mitigation? date: - - journal: journal of outdoor recreation and tourism doi: . /j.jort. . sha: doc_id: cord_uid: z c thl the paper presents the status quo on climate change impacts on city tourism in austria describing the impacts by air travel and a short stay on the greenhouse gas emissions and the changing conditions in the city. for austrian cities, depending on location and topography, heavy rainfall events, storms and heat waves in particular could become increasingly relevant in the tourism context. for medium-sized and large cities, heat is the most frequently discussed topic in connection with possible adaptation potentials. the analysis of challenges shows a strong overlap of adaptation targets in city tourism with adaptation challenges for city planning including connection to the sub-urban surrounding areas to confront climate change impacts. covid- pandemic, additionally, offered the opportunity to discuss a new re-start of the city-tourism against the experience during the shutdown period in spring . the paper argues that we can learn from the current health crisis for coping with climate change related extreme events and to increase achievements in climate change mitigation. firstly, the pandemic provides a strong ability to discuss the impact of city tourism due to short-term air travel and options to enhance more climate-friendly options on the other hand. secondly, covid- emphasized the need to reconsider the role of free spaces in metropolitan areas as well as their accessibility. herewith synergies with climate change adaptation are likely when questioning the availability and accessibility of green and blue infrastructure as well as their capacities. challenges including crowding and impacts by over tourism on public free spaces will require joint strategies involving all public and private institutions (including local communities and businesses) responsible for the maintenance of green and blue free spaces. thirdly, the strong interactions between urban and suburban areas became evident once more, which will also be very relevant for city tourism in the future (e.g. in times of heat waves). reflection on the transferability of coping with such crowding effects, related to the adaptive behaviour of residents and tourists in times of severe heat waves, might be relevant for both city tourism and summer tourism destinations near metropolitan areas. finally, the covid- crisis encourages discussions on over-tourism in metropolitan destinations in favour of a more balanced approach, in particular in inner city areas and around major sightseeing attractions. a look at the composition of tourism offers for austria shows that city tourism plays a very special and significant role. particularly vienna and salzburg are very attractive cities for round trips of us and asian tourists, not only because of their location in the centre of europe but also due to their world-wide recognition (e.g. containment in listings such as "travel usnews"). many austrian cities are also visited by european guests because of their special events and unique cultural heritage. with regard to greenhouse gas emissions, short city trips can be considered as particularly climate-unfriendly, as frequently aviation is used as mode of transport to and from the city destination. for this reason, it seemed important to us to deal with this aspect in this special issue and to include data to illustrate the current situation as well as concepts for adaptation and mitigation. however, when the paper had already put together the most important facts, the sudden lock-down due to the covid- pandemic affected tourism activities worldwide. since significant long-term impacts are expected due to the pandemic, especially in city tourism, the paper at hand aims at compiling not only the previous findings on climate change and city tourism, but also the expected consequences of the pandemic lock down. finally, we want to discuss whether and if so, how far, the experiences from the covid- pandemic could influence future city tourism developments and provide valuable new insights. before the covid- pandemic, city tourism had significantly increased europe-wide, sometimes already leading to discussions over capacity limits and "overtourism" (goodwin, ) . in austriathe focus country of this special issuethe demand for city tourism in summer has also risen steadily over the past ten years (fleischhacker, ) . the increased demand for city breaks reflects an overall trend towards more short-term and flexible holiday planning (zellmann & mayrhofer, and to more frequent short holidays (wirtschaftskammer tirol, ; wko, ) . in the last decade, on a year-round basis, cultural, sightseeing and city tourism accounted for almost % of all travelling in austria (statistik austria, austria, , . for vienna, austria's largest city destination, arrivals showed an increase over the past ten years (ma dezernat statistik wien, a) . a comparison with other capital cities in europe such as berlin, stockholm or prag show that after the economic crisis ( - ) most city destinations had a significant tourism growth. for vienna, the development resulted in a more than % increase from onwards (ma dezernat statistik wien, a) . looking at the sources for city tourism in austria, germany was the most important country in terms of source markets. regarding national guests-the second most important source market for tourism in austria's capitalthe most recent statistics from showed a marked increase of % in overnight stays compared to . with a greater marginthe united states represented the third most important source market for trips to vienna (ma dezernat statistik wien, b) . in innsbruck and salzburg, the two most important medium-sized urban destinations in austria, the number of overnight stays in the summer season has also risen steadily over the past ten years. innsbruck, for example, had recorded approx. , overnight stays in and already approx. , in (stadt innsbruck, a). salzburg, meanwhile, reported a little more than million overnight stays in between may and august alone, which had increased to approx. . million by in the same period (land salzburg, ). regarding their main source markets the larger cities in austria differ, however, from vienna. in innsbruck for example, domestic guests were the most important source market, followed by visitors from germany and italy. visitors from the united states represented the fourth most important source market in this case (stadt innsbruck, b) . further significant source markets for austrian city tourism were china, russia and (in summer) the united arab emirates (wien tourismus, ) . especially guests from china (and other asian countries) were expected to increase before covid- , even considering the very heterogeneous chinese source market (thuen jørgensen et al., ) . according to their size, the impact of the increase in visitors was very diverse for the austrian cities and their infrastructure and population. for the city of salzburg the correlation can be described with . overnight stays per inhabitant. in vienna this correlation is only . overnight stays per inhabitant. the net lodging revenue per available room night was in in salzburg at . euros, in vienna at . euros. therefore effects of perceived crowding are for the inhabitants in salzburg significant but the revenue is (only) about the same compared to vienna (pröbstl-haider, , p. ) . for austrian cities, depending on location and topography, heavy rainfall events, storms and heat waves in particular could become increasingly relevant in the tourism context. for medium-sized and large cities, heat is the most frequently discussed topic in connection with possible adaptation potentials (fleischhacker & formayer, ; kromp-kolb et al., ; fleischhacker et al., ; götz et al., ; steininger, bednar-friedl, formayer, & könig, ; stadt wien, ) . however, there is an apparent difference between the perceived heat stress of the urban population and visiting guests. recent studies from small to medium size cities in austria such as graz and leibnitz (babcicky & seebauer, ) showed that the resident population has already experienced more difficult living and working conditions due to longer periods of heat days and tropical nights in the previous summers with longer heat waves (e.g. in ). similarly, a survey of the viennese population (juschten, brandenburg, et al., and b) showed that for a large metropolitan area, almost half of respondents perceived the warm temperatures of their city apartments as still "tolerable", while little more than a third of respondents already considered the heat as a definite burden. for the extremely hot summer of , around % indicated that they found the heat "stressful" and "difficult at night" (juschten, brandenburg, et al., ) . over the past ten years, a number of international studies have examined the influence of weather or climatic conditions on booking decisions (dubois et al., ; fur, ; gómez-martín et al., ; krajasits et al., ; serquet & rebetez, ; zellmann & mayrhofer, ) . dubois et al. ( ) showed for a french sample that predicted heat waves generally have less influence on changes in travel decisions than forecast bad weather and cold spells. even in hindsight, memories of rainy periodsespecially during longer vacationsare much more negatively perceived than those of heat waves at a holiday destination. gössling et al. ( ) examined the complexities of classifying travel weather as "extreme", and the strong variation in the longer-term effect of the associated memories. serquet and rebetez ( ) and dubois et al. ( ) showed that there generally appears to be high "heat tolerance" among travellers. compared to other forms of travel, acceptable temperatures (before they are perceived as "too hot" by tourists) are higher for city breaks than for stays in mountainous areas, for example. this is also reflected in the past development of vienna's tourism industry, which has not yet shown any negative trends in hot summers. on the contrary, it confirms a steady trend towards highest booking levels in the summer months of july and august (wien tourismus, ) . considering the five hottest summers of the past ten years ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) , not only does a strong increase in city tourism become apparent, but also the strongest increase in demand of any summer tourism category (fleischhacker, ) . thus, actual, statistics-based demand has so far provided no indication of a negative impact of possible heat strain on austrian city tourism. however, in their survey of vienna tourists almost ten years ago, allex et al. ( a) showed that . % of respondents had already adapted their sightseeing programmes due to heat. they revealed a shift in activities, where visitors would deliberately plan longer breaks or seek out cooler places. differences were most significant in the case of longer-duration stays, where programmes were adjusted much more frequently. numerous publications have emphasized heat stress in cities as a major problem demanding a considerable adaptation effort and urgent action on the part of urban planning. for example, the "austrian strategy for adaptation to climate change" (bmlfuw, ) devotes a separate chapter to green and open spaces in cities, including recommended measures. the city of vienna, meanwhile, has specifically addressed the issue of "urban heat islands". the result is a strategic plan identifying measures to counteract the increased warming of the city area (brandenburg et al., . the federal office for the environment in switzerland recommends similar measures (bundesamt für umwelt (bafu), ). further benefits for reducing heat islands can also be achieved through suitable open spaces -"green and blue infrastructure" in terms of a strategically planned network of natural and semi-natural areas (ec, ) -which absorb precipitation and reduce water runoff, even maintaining their retention function during heavy rainfall events (eurac, ) . these measures primarily benefit the local population, but there may also be positive synergies for city tourism. preserving or enhancing green spaces and their diverse uses, creating water-related structures in public spaces, as well as establishing an offer of water-based sports and recreational activities andwherever possiblewater-based mobility, can represent valuable elements for the design of summer tourism offers in city tourism. in addition to green and blue infrastructure, there will also be a need for adaptation in the cooling of buildings (see lund-durlacher and gössling -reference to other publications in the special issue). due to the fact that some accommodation categories are still very poorly equipped with cooling systems in comparison to other countries, climate-compatible cooling is all the more important to prevent maladaptation (bmwfj, ; allex et al., a; bmwfw & Ö hv, ) . adaptation regarding the choice of accommodation is also conceivable, e.g. by shifting preferences to the greener suburbs or the outskirts of the city. as yet, however, there are no concrete studies on this issue. here, too, the aforementioned capacity limits during heat waves are a planning factor that will likely require increased attention. in this context, also co-benefits for climate change mitigation (see . ) respectively avoidance of maladaptation become relevant when planning transport option to the metropolitan area. . in the future, resource conflicts will also play a greater role in the case of water. as the provision of drinking water is another important aspect besides the cooling of buildings, this might be challenging for austrian cities on the long-term perspective too. so far, the city of vienna has installed several drinking water fountains as well as water playgrounds, water distribution elements creating humid fog and several other activities related to water-induced cooling effects (allex et al., b (allex et al., , . to manage also the aspects of sustainable (drinking) water management, tourism will have to engage with the other sectors, just as other sectors will have to coordinate their water saving measures with tourism, in order to promote synergies. intercontinental flights have a negative impact on global climate, especially without compensation , andcontingent on the total length of stay in europe and the choice of transport within the continentthey are the primary factor determining the co balance of city breaks. considering the typically short length of stay compared to other forms of travel, and assuming repeated trips to urban destinations within a single year, the intra-european travel activities of city breakers also have a negative impact on climate change if they are conducted by air plane (in particular without compensation) or car. for the encouragement to foster climate change mitigation targets, there is moreover a significant difference whether the city itself is the main destination of a trip or just one of several attractions of a nearby holiday destination (e.g. bad weather programme for rural tourism or day trip destination on a cultural and culinary round-trip). travellers who are specifically planning a city break to an urban destination may be more drawn to arrangements combining climate-friendly travel and accommodation. in contrast to other forms of travel, transport within the destination is already predominantly climate-friendly in the case of city tourism in medium to large austrian cities such as vienna or graz, due to the public transport services available in the urban destinations. for some urban destinations parking a private car became very expensive and limitations are in place in several city districts/areas. therefore, there is still further potential to promote travel by public transport also for the arrival, especially as no additional equipment (as is necessary for winter sports, for example) needs to be transported for city breaks, and because public transport is already predominantly used for the "last mile". in some cases, incentives for climate-friendly travel to city hotels have already been introduced such as e.g. discounts on overnight rates upon presentation of a train ticket or another proof of another climatefriendly mode of travel (e.g. for the "hotel stadthalle" in vienna). cooperation of transport companies with both the hotel industry and tourism advertising is important in this context. for business travellers in particular, who account for a significant proportion of city trips (reference), making climate-friendly travel to the destination more attractive is an important challenge, in addition to the already existing initiatives to promote and market climate-friendly mobility within the urban destination (e.g. conference tickets for public transport). since business travellers related to conferences and large-scale events (e.g. fairs, large-scale traning courses, company events) align their travel arrangements primarily according to aspects of expediency, it is upon conference organisers and companies organising "green events" (e.g. as according to the declaration of the austrian ministry of the environment), including transport to and within the destination as a matter of concern and to raise awareness for these issues at the time the city trip is planned. the city of vienna and the vienna convention bureau are already strongly encouraging the use of public transport in the destination but could communicate more intensively alternative arrival options by climate-friendly transport modalities at large scale as well as to foster distribution of information adequately. while the existing urban infrastructure is jointly used by city tourists, in line with the diversity of offers, accommodation plays a major role in terms of the overall climate balance. in this context, cooling and other adaptation measures to heat have become increasingly important factors for climate change mitigation. guidance such as bmwfw, wko & Ö hv ( ) outlines the relvant measures and are accompanied by funding to reduce energy consumption and enhance the thermal regulation of hotel buildings. for austrian city tourism, there is still space for improvement left looking across all categories of accommodation facilities and their diverse building structures. at the beginning of the crisis in march some federal states in austria closed hotels. finally, around easter the federal government closed all hotels in austria, for touristic purposes. additionally, borders were closed to all neighboring countries from the beginning of the lockdown onwards. internationally, air travel was also mainly shut down from the end of march until the end of june . airlines such as austrian airlines, swiss and lufthansa, received significant financial support by the respective states to be able to continue their business, other smaller low-budget airlines were particularly affected too. from the th of may the hotels in austria were allowed to reopen again if fulfilling certain hygienic conditions. the opportunities for most european countries to travel again started around the june , and austrian borders were opened for some neighboring countries such as germany and switzerland (sozialministerium, ) . other neighboring countries followed at the end of june respectively the beginning of july. conferences and fairs were cancelled over summer still at a certain size, but are scheduled for early autumn again. nevertheless it remains questionable, how far this plan can be continued. since the planning conditions are again unclear in midsummer, this business-related segment is not very likely to be able to recover soon from the pandemic impacts. the planning for large-scale events in sport and culture (e.g. festivals) is also possible for only. for instance, even outdoors, the large concert of the viennese philharmonics, which was postponed from june to september, was cancelled again. this is particularly relevant, as one of the main motives for city tourism is experiencing "culture". regarding "summer holiday types", according to the austrian chamber of commerce (wko, ), cultural holidays accounted for % of total holidays in austria during the summer season. the research association for holidays and travel (fur, ) presented similar numbers for the german source market: cultural trips also had a % share in the category "short breaks ". the motive "sights and culture" is particularly highlighted in studies involving city travellers. asked about their visit to vienna, % of guests cited "sights & culture" as the basis for their decision (wien tourismus, ) . current studies such as henry-biabaud ( ) expect, however, individual cultural attractions and well-known sights can be better positioned during (or possibly shortly after) the pandemic than city destinations as a whole. overall, regarding austria's most important source markets for city tourism, especially in the case of vienna, it is clear that some important source markets have been particularly affected by covid- . it is uncertain to what extent the economic and socio-economic consequences of covid- and related measures will affect the travel behaviour of americans, italians, spaniards and the british. therefore, amongst other reasons, the austrian tourism branch expects a slow recover of the city tourism and experienced a decrease of about % in june, july and august compared to the season already (kurier, ) . globally, recent studies (trimble et al., ) don't expect a complete recovery of arrivals in european city tourism before . short city breaks are likely to be given lower priority over the main annual holiday. however, experts such as henry-biabaud ( ) currently assume that europeans will continue to show an interest in city breaks in the mid-term perspective. for how long and to what extent the chinese source market will remain changed is not yet foreseeable. recent studies (xiang, ) show that two-thirds of chinese are already interested in travelling again, but are focused on the domestic and regional markets for the time being. due to asian guests' comparatively short length of stay, their contribution to value creation in the individual city destinations is significantly lower compared to visitors from other source markets. in the short to medium term, russia and the united arab emirates will also be affected by the low oil price, which will likely lead to disadvantages in the high and premium-priced city hotel sectors. typical carriers such as ryanair expect for the next years a reduction of % (die zeit, ). during the covid- pandemic, we were experiencing the implications of scarcity of certain resources, such as a lack of green space in metropolitan areas making it difficult to maintain the necessary distance to avoid spreading infection. problems were aggravated as access to recreational areas and green spaces in cities was partly blocked and nearby surrounding green spaces were strictly limited to residents' use only. the residents and few visitors also experienced a lack of coordination between the responsible institutions. in vienna, for example, large parks in densely populated areas remained shut for several weeks in opposition to the will of the municipal government. the competencies for these specific parks belonged to the federal ministry at the national level. because of the need to socially distance from others during the covid- pandemic, inhabitants of vienna spread across protected areas when carrying out their leisure time activities in vienna's larger metropolitan areas which also includes protected areas such as a national park or a biosphere reserve. this high amount of visitation hasat this time of the year -very likely led to negative consequences particularly for breeding animals according to statements of the protected areas management. during the pandemic, the strong interactions between urban and suburban areas were also shut down. the large recreation areas around lake neusiedl for instance, which includes the largest body of water in eastern austria and is situated only about km from the eastern border of vienna (municipality) respectively about km from the inner city (e. g. stephansplatz), was no longer accessible to non-residents due to a new restriction by the state governor aimed at preventing crowding along the lake shore and allowing locals to use these areas while maintaining the necessary distance. these limitations remained only for a very short time in place due to the strong protest of authorities, media and public from outside the burgenland. covid- also changed the overall transportation behaviour in the city. despite the excellent conditions -e.g. in vienna -the transportation system was less used and perceived as a dangerous place. how long any inhibition to fully return to the use of public transport will last, is uncertain and depends on many factors. in the mid-term, however, this aspect will hopefully no longer play a role. despite the completely diverse origin of difficulties, it seems we can learn from the current health crisis for coping with climate change related extreme events and attempts to minimize climate change. firstly, we see a strong ability to reduce air-born travelling. depending on the future source markets (us, uk, china, russia and, in the summer, the united arab emirates) travel to austria's cities is also in the future likely to happen by air via the airports of vienna, munich or innsbruck and salzburg in combination with intercity rail transport to other urban destinations. however, a reduced offer on one hand and new air taxes discussed across europe may make this kind of travelling less attractive. during the covid- pandemic all these short distance flights and the many city breaks for shopping in london or cultural events in salzburg or vienna were impossible. even business flights are likely to remain after covid- less attractive. climate policy including taxes and airport fees may simulate this post covid- situation. newspapers and companies discuss whether this reduced post-covid- standard is likely to be kept even after the pandemic. we might be able to refer to scenarios post covid- were source markets changed to more regional, national and continental arrivals. however, we also see a threat in context of climate change mitigation when individual car travel is increasing. secondly, covid- emphasized the need to reconsider free spaces in metropolitan areas. herewith synergies with climate change adaptation are likely when questioning the availability and accessibility of green and blue infrastructure as well as their capacities. looking at the measures taken in response to the additional space requirements in times of the covid- pandemic, we can see that challenges arose primarily in terms of the competencies of, and the need for coordination between, the responsible institutions. challenges including crowding and impacts by over tourism on public free spaces will require joint strategies involving all public and private institutions responsible for the maintenance of green and blue free spaces. thirdly, the strong interactions between urban and suburban areas became evident. similar as in times of covid- in spring also in times of heat waves, recreational areas close to large cities may become even more crowded due to urban citizens escaping urban heat islands (juschten et al., ) . restrictions may follow (and partly be necessary) to avoid damages, and trade-offs between tourists and local residents may become a bigger issue over the coming decades, in particular in suburban areas which do not effectively but also sustainably profit from day tourism activities. at the same time, metropolitan residents' adaptation needs (such as escaping to refreshing green areas) need to be considered carefully to prevent potential negative impacts on their health and well-being, e.g. if these areas should become crowded with tourists. limited access to resources such as recreational areas, e.g. due to a need to close some of these structures, can lead to stronger impacts on other the green and blue resources of cities. heat waves may also increase the attractiveness of urban forests, parks and nearby protected areas, similar to the time of the covid- pandemic. to prevent the experienced negative impacts also in times of heat waves, when both residents and tourists might seek refreshment in nearby areas (juschten et al., ) interdisciplinary strategies including tourism management, nature protection and city planning are needed, so that there is no overcrowding in these areas. the crucial aspect to consider for the future is, whether some installations could be limited to residents also in times of severe crowding and overuse e.g. when citizens and tourists merge in time of heat waves and/or the lake is impacted by drought (as it is the case at the moment). we have already seen how actions and procedures which had not already been laid down before the crisis (which, of course, was not expected by the governing institutions) can lead to controversy. reflection on the transferability of coping with such crowding effects, related to the adaptive behaviour of residents and tourists in times of severe heat waves, might be relevant for both city tourism and summer tourism destinations near metropolitan areas. a combination with drought might even increase the conflicts of interest, e.g. in near-metropolitan and metropolitan forest areas, which might be limited in accessibility to avoid the risks of forest fires. finally, the covid- crisis encourages discussions on both the limits of tourism growth and over-tourism. based on scenarios before and post covid- we are able to discuss a more balanced approach, in particular in inner city areas and around major sightseeing attractions. in this context the duration of a city break is an essential factor, which allows having less people at the destination, who spend more money over a longer time-frame visiting also more and diverse attractions. the pandemic crisis gives us the opportunity to discuss our travel behaviour of the past, to check the feasibility of adaptation measures and to define the new "normal". the ability to travel is a crucial element of democratic countries. despite reduced travelling activities we still saw the desire of people to continue to go elsewhere than home in the vacation time even in the "pandemic-summer" of (kurier, ) . however, city trips such as rome-vienna -rome for euro have been a development which was far beyond sustainable. the value of travelling may gain importance (as the first trip to nature after the covid- lock down), if it is thoughtfully planned and not too cheap. to what extent the prices will increase, will not only depend on climate change mitigation measures but also depend on how hard the european and non-european countries important for austrian city tourism, such as the united states of america, are hit by the economic crisis that is likely to follow. in the interest of climate change mitigation, promotion of the two main source markets germany and austria followed by the other nearby european source markets would have been preferable even before covid- , especially if public transport options were expanded and more intensively marketed at the same time. looking at the summer season we also see, however, that at the moment guests from austria and germany prefer other forms of tourism such as lake and mountain tourism (kurier, ) . some tourism operators and the hospitality industry in austria used the covid- crisis to enhance quality-oriented tourism and focus on renovation activities some others planned to make their services more sustainable by approaching new, diverse target group(s). however, the paper at hand also shows that moving away from the city-tourism we know requires more engagement including climate friendly travelling, city planning, a cooperative and integrated concept with the hinterland and city tourism products which truly support the regional economy due to a longer stay. if we are able to learn the significant lesson from the covid- crisis remains to be seen. while city tourism showed very strong growth within overall tourism demand before the covid- pandemic, it is currently one of the most strongly impacted segments in austria's tourism. the extent to which economic and social consequences of the covid- virus pandemic will continue to affect the most important source markets in the short and medium term is still unclear. on the positive side, however, european guests account for a large share of both european and austrian city tourism. despite the border openings within the eu -which happened starting from mid-juneswifter recovery was not possible for city tourism so far and seems still not reachable in the short to medium-term. especially with regard to climate change adaptation, the covid- virus crisis may also give rise to possible lessons learned for urban tourism. adaptation options for urban tourism arise primarily from the increased frequency of heat waves and their effects on the aggravation of urban heat islands (high agreement, strong evidence). even if past statistics have shown that heat stress in particular had little influence on booking behaviour, nevertheless there has been little research on the future influence of extreme events on city tourism in austria. links between heat tolerance and the motives of different target groups, but also the influence of urban planning parameters (e.g. the proportion of green space), have also scarcely been considered in the context of austrian urban tourism to date. synergies for tourism can result from the adaptation goals of urban development and open space planning, in particular the greening of densely built-up areas as well as the cooling of large public spaces (again, high agreement and strong evidence). important aspects are the availability and accessibility of green and blue infrastructure as well as the (maximum) accepted distance to reach it (or alternative, indoor attractions in cool buildings), depending on the target group. an analysis of varying acceptance depending on the source market would also be important in this regard. furthermore, as allex et al. ( a) first demonstrated, sightseeing routes could shift as attractions are getting too hot. furthermore, the acceptable walking distance between sights might decreases in hot weather larger green areas and bodies of water could be increasingly integrated into the design of tourism offers, as could cooler indoor activities (e.g. visits to cultural institutions, churches, etc.). correspondingly, their connection by public transport and other transportation means (bike, e-bike, e-scooter) must be considered, but the interests of the urban population must also be protected (high agreement, medium evidence). alternatively, the capacity of airconditioned public transport connections between tourist attractions should be examined, as demand for the use of individual lines could increase. it may also be necessary to consider shorter intervals in mobility planning. current, concrete studies for the austrian urban destinations (especially vienna and graz with their strongly increasing heat levels) on the acceptance of measures or changes in daily tourist programmes can provide valuable information for marketing and product design. finally, conflicts over open spaces in urban areas and the surrounding countryside have increased during the covid- pandemic or have escalated dramatically for the first time in some cases. it could prove highly important to discuss responsibilities, particularly across all types of legislative and operational "borders" (e.g. between urban and suburban areas or between different federal states), early enough to adapt concrete cross-sectoral action plans involving all responsible institutions, to adjust data sources and the performance of monitoring systems for recreational areas (especially protected areas in and near large metropolitan areas), and to identify the consequences of decisions, including the pros and cons for tourism, residents and existing nature conservation targets, based on an interdisciplinary perspective. alexandra jiricka-pürrer: conceptualization, formal analysis, investigation, methodology, writing -original draft, writing -review & editing. christiane brandenburg: formal analysis, investigation, writing -original draft. ulrike pröbstl-haider: formal analysis, funding acquisition, methodology, project administration, resources, writing -original draft. hot town, summer in the city -entwicklung von hitzerelevanten anpassungsstrategien im städtetourismus hot town, summer in the city -die auswirkungen von hitzetagen auf das freizeit-und erholungsverhalten sowie das besichtigungsprogramm von städtetouristinnendargestellt am beispiel wiens. endbericht von start-clim familie und jugend patch:es private adaptation to climate change die österreichische strategie zur anpassung an den klimawandel die neue Ö sterreichische tourismusstrategie. wien: bundesministerium für wirtschaft energiemanagement in der hotellerie und gastronomie: ein leitfaden, . auflage. wien: bmwfw urban heat islands -strategieplan wien hitze in städten. bern: grundlagen für eine klimagerechte stadtentwicklung die regierung soll den mund halten und zahlen weather preferences of french tourists: lessons for climate change impact assessment supporting the implementation of green infrastructure (final report. brussels) itr-tourismusreport die sensitivität des sommertourismus in Ö sterreich auf den klimawandel erste ausgewählte ergebnisse der tourists, weather and climate. official tourism promotion websites as a source of information the challenge of overtourism it was raining all the time!': ex post tourist weather perceptions anpassung an den klimawandel in der schweiz. ziele, herausforderungen und handlungsfelder. erster teil der strategie des bundesrates out of the city heat -way to less or more sustainable futures? sustainability the mountains are calling, an extended tpb model for understanding metropolitan residents' intentions to visit nearby alpine destinations in summer also wiki alpiner sommertourismus in Ö sterreich und mögliche wirkungen des klimawandels auswirkungen des klimawandels auf wien unter besonderer berücksichtigung von klimaszenarien der sommertourismus nimmt etwas fahrt auf tourismusstatistik, zahlen, fakten, daten. die bisherige sommersaison gästeankünfte in wien nach herkunftsländern nächtigungen in wien (top destinationsentwicklung in den alpen: ein spagat zwischen underund over-tourism ? apcc special report on tourism, large culture and sport events and climate change relationship between tourism demand in the swiss alps and hot summer air temperatures associated with climate change statistiken zahlen, tourismus, ankünfte und Übernachtungen nach beherbergungsarten in den sommerhalbjahren statistiken zahlen, tourismus, Übernachtungen in den gewerblichen beherbergungsbetrieben nach ausgewählten herkunftsländern klimatologische kenntage in wien herausgegeben von bundesanstalt statistik Ö sterreich pressemitteilung, consistent economic cross-sectoral climate change impact scenario analysis: method and application to austria understanding the past, anticipating the future -a critical assessment of china outbound tourism research travel usnews (s.t covid- : pandemic impacts on european city tourism der wiener urlaubsgast (private urlaube in entgeltlichen unterkünften tourismus: die sommerfrische ist wieder da. wirtschaft. tirol tourismus und freizeitwirtschaft in zahlen: Ö sterreichische und internationale tourismus-und wirtschaftsdaten. . ausgabe, februar . herausgegeben von wirtschaftskammer Ö sterreich bundessparte tourismus und freizeitwirtschaft die urlaubsrepublik: die zukunft des tourismus in Ö sterreich this discussion note results from a special report on climate change and tourism funded by the austrian climate research programme (acrp) pertaining to the austrian climate and energy fund. key: cord- -tpqsjjet authors: nan title: section ii: poster sessions date: - - journal: j urban health doi: . /jurban/jti sha: doc_id: cord_uid: tpqsjjet nan food and nutrition programs in large urban areas have not traditionally followed a systems approach towards mitigating food related health issues, and instead have relied upon specific issue interventions char deal with downstream indicators of illness and disease. in june of , the san francisco food alliance, a group of city agencies, community based organizations and residents, initiated a collahorarive indicator project called rhe san francisco food and agriculture assessment. in order to attend to root causes of food related illnesses and diseases, the purpose of the assessment is to provide a holistic, systemic view of san francisco\'s food system with a focus on three main areas that have a profound affect on urban public health: food assistance, urban agriculture, and food retailing. using participatory, consensus methods, the san francisco food alliance jointly developed a sec of indicators to assess the state of the local food system and co set benchmarks for future analysis. members collected data from various city and stare departments as well as community based organizations. through the use of geographic information systems software, a series of maps were created to illustrate the assets and limitations within the food system in different neighborhoods and throughout the city as a whole. this participatory assessment process illustrates how to more effectively attend to structural food systems issues in large urban areas by ( t) focusing on prevention rather than crisis management, ( ) emphasizing collaboration to ensure institutional and structural changes, and ( ) aptly translating data into meaningful community driven prevention activities. to ~xplore the strategies to overcome barriers to population sample, we examined the data from three rapid surveys conducted at los angeles county (lac). the surveys were community-based partic· patory surveys utilizing a modified two-stage cluster survey method. the field modifications of the method resulted in better design effect than conventional cluster sample survey (design effect dose to that if the survey was done as simple random sample survey of the same size). the surveys were con· ducte~ among parents of hispanic and african american children in lac. geographic area was selected and d .v ded int.o small c~usters. in the first stage, clusters were selected with probability proportionate to estimated size of children from the census data. these clusters were enumerated to identify and develop a list of households with eligible children from where a random sample was withdrawn. data collectmn for consented respondents involved - minutes in-home interview and abstraction of infor· ma~ion from vaccine record card. the survey staff had implemented community outreach activities designed to fost~r an~ maintain community trust and cooperation. the successful strategies included: developing re.lat on .w. th local community organizations; recruitment of community personnel and pro· vide them with training to conduct the enumeration and interview; teaming the trained community introduction: though much research has been done on the health and social benefits of pet ownership for many groups, there have been no explorations of what pet ownership can mean to adults who are marginalized, living on fixed incomes or on the street in canada. we are a community group of researchers from downtown toronto. made up of front line staff and community members, we believe that community research is important so that our concerns, visions, views and values are presented by us. we also believe that research can and should lead to social change. method: using qualitative and exploratory methods, we have investigated how pet ownership enriched and challenged the lives of homeless and transitionally housed people. our research team photographed and conducted one-on-one interviews with pet owners who have experienced home· lessncss and live on fixed incomes. we had community participation in the research through a partnership with the fred vicror centre camera club. many of the fred victor centre camera club members have experienced homelessness and being marginalized because of poverty. the members of the dub took the photos and assisted in developing the photos. they also participated in the presenta· tion of our project. results: we found that pet ownership brings important health and social benefits to our partici· pants. in one of the most poignant statements, one participant said that pet ownership " ... stops you from being invisible." another commented that "well, he taught me to slow down, cut down the heavy drugs .. " we also found that pet ownership brings challenges that can at times be difficult when one is liv· ing on a fixed income. we found that the most difficult thing for most of the pet owners was finding affordable vet care for their animals. conclusion: as a group, we decided that research should only be done if we try to make some cha.nges about what we have learned. we continue the project through exploring means of affecting social change--for example, ~eti.tions and informing others about the result of our project. we would like to present our ~mdmgs and experience with community-based participatory action resea.rch m an oral. presentarton at yo~r conference in october. our presentation will include com· mumty representation ~f. both front-hne staff and people with lived experience of marginalization and homdessness. if this is not accepted as an oral presentation, we are willing to present the project m poster format. introduction the concept of a healthy city was adopted by the world health organization some time ago and it includes strong support for local involvement in problem solving and implementation of solutions. while aimed at improving social, economic or environmental conditions in a given community, more significantly the process is considered to be a building block for poliq reform and larger scale 'hange, i.e. "acting locally while thinking globally." neighbourhood planning can he the entry point for citizens to hegin engaging with neighbours on issues of the greater common good. methods: this presentation will outline how two community driven projects have unfolded to address air pollution. the first was an uphill push to create bike lanes where car lanes previously existed and the second is an ongoing, multi-sectoral round table focused on pollution and planning. both dt•monstrate the importance of having support with the process and a health focus. borrowing from traditions of "technical aid"• and community development the health promoter /planner has incorporated a range of "determinants of health" into neighbourhood planning discussions. as in most urban conditions the physical environment is linked to a range of health stressors such as social isolation, crowding, noise, lack of open space /recreation, mobility and safety. however typical planning processes do not hring in a health perspective. health as a focus for neighbourhood planning is a powerful starti_ng point when discussing transportation planning or changing land-uses. by raising awareness on determmants of health, citizens can begin to better understand how to engage in a process and affect change. often local level politics are involved and citizens witness policy change in action. the environmental liaison committee and the dundas east hike lanes project resulted from local level initiatives aimed at finding solutions to air pollution -a priority identified hy the community. srchc supported the process with facilitation and technical aid. _the processs had tangible results that ultimately improve living conditions and health. •tn the united kmgdom plannm in the 's established "technical aid" offices much like our present day legal aid system to provide professional support and advocacy for communities undergoing change. p - (c) integrating community based research: the experience of street health, a community service agency i.aura cowan and jacqueline wood street health began offering services to homeless men and women in east downtown ~oronto in . nursing stations at drop-in centres and shelters were fo~lowed by hiv/aids prevent ~, harm reduction and mental health outreach, hepatitis c support, sleeping bag exchange, and personal tdennfication replacement and storage programs. as street health's progi;ams expanded, so to~ did the agency:s recognition that more nee~ed t~ be done to. address the underl~ing causes of, th~ soct~l and economic exclusion experienced by its clients. knowing t.h~t. a~voca~y ts. helped by . evtd~nce , street he.alt~ embarked on a community-based research (cbr) initiative to dent fy commumty-dnven research priorities within the homeless and underhoused population. methods: five focus groups were conducted with homeless people, asking participants to identify positive and negative forces in their lives, and which topics were important to take action on and learn more about. findings were validated through a validation meeting with participants. results: participants identified several important positive and negative forces in their lives. key positive forces included caring and respectful service delivery, hopefulness and peer networks. key negative forces included lack of access to adequate housing and income security, poor service delivery and negative perceptions of homeless people. five topics for future research emerged from the process, focusing on funding to address homelessness and housing; use of community services for homeless people; the daily survival needs of homeless people and barriers to transitioning out of homelessness; new approaches to service delivery that foster empowerment; and policy makers' understanding of poverty and homelessness. conclusions: although participants expressed numerous issues and provided much valuable insight, definitive research ideas and action areas were not clearly identified by participants. however, engagement in a cbr process led to some important lessons and benefits for street health. we learned that the community involvement of homeless people and front-line staff is critical to ensuring relevance and validity for a research project; that existing strong relationships with community parmers are essential to the successful implementation of a project involving marginalized groups; and that an action approach focusing on positive change can make research relevant to directly affected people and community agency staff. street health benefited from using a cbr approach, as the research process facilitated capacity building among staff and within the organization as a whole. p - (c) a collaborative process to achieve access to primary health care for black women and women of colour: a model of community based participartory research notisha massaquoi, charmaine williams, amoaba gooden, and tulika agerwal in the current healthcare environment, a significant number of black women and women of color face barriers to accessing effective, high quality services. research has identified several issues that contribute to decreased access to primary health care for this population however racism has emerged as an overarching determinant of health and healthcare access. this is further amplified by simultaneous membership in multiple groups that experience discrimination and barriers to healthcare for example those affected by sexism, homelessness, poverty, homophobia and heterosexism, disability and hiv infection. the collaborative process to achieve access to primary health care for black women and women of colour project was developed with the university of toronto faculty of social work and five community partners using a collaborative methodology to address a pressing need within the community ro increase access to primary health care for black women and women of colour. women's health in women's hands community health centre, sistering, parkdale community health centre, rexdale community health centre and planed parenthood of toronto developed this community-based participatory-action research project to collaboratively barriers affecting these women, and to develop a model of care that will increase their access to health services. this framework was developed using a process which ensured that community members from the target population and service providers working in multiculrural clinical settings, were a part of the research process. they were given the opportunity to shape the course of action, from the design of the project to the evaluation and dissemination phase. empowerment is a goal of the participatory action process, therefore, the research process has deliberately prioritized _ro enabling women to increase control over their health and well-being. in this session, the presenters will explore community-based participatory research and how such a model can be useful for understanding and contextualizing the experiences of black women and women of colour. they will address. the development and use of community parmerships, design and implementation of the research prorect, challenges encountered, lessons learnt and action outcomes. they will examine how the results from a collaborative community-based research project can be used as an action strategy to poster sessions v address che social determinants of women health. finally the session will provide tools for service providers and researchers to explore ways to increase partnerships and to integrate strategies to meet the needs of che target population who face multiple barriers to accessing services. lynn scruby and rachel rapaport beck the purpose of this project was ro bring traditionally disenfranchised winnipeg and surrounding area women into decision-making roles. the researchers have built upon the relationships and information gachered from a pilot project and enhanced the role of input from participants on their policy prioriries. the project is guided by an advisory committee consisting of program providers and community representatives, as well as the researchers. participants included program users at four family resource cencres, two in winnipeg and two located rurally, where they participated in focus groups. the participants answered a series of questions relating to their contact with government services and then provided inpuc as to their perceptions for needed changes within government policy. following data analysis, the researchers will return to the four centres to share the information and continue che discussion on methods for advocating for change. recommendations for program planning and policy development and implementation will be discussed and have relevance to all participants in the research program. women's health vera lefranc, louise hara, denise darrell, sonya boyce, and colleen reid women's experiences with paid and unpaid work, and with the formal and informal economies, have shifted over the last years. in british columbia, women's employability is affected by government legislation, federal and provincial policy changes, and local practices. two years ago we formed the coalition ior women's economic advancement to explore ways of dealing with women's worsening economic situations. since the formation of the coalition we have discussed the need for research into women's employabilicy and how women were coping and surviving. we also identified how the need to document the nature of women's employability and reliance on the informal economy bore significanc mechodological and ethical challenges. inherent in our approach is a social model of women's health that recognizes health as containing social, economic, and environmental determinants. we aim to examine the social contexc of women's healch by exploring and legitimizing women's own experiences, challenging medical dominance in understandings of health, and explaining women's health in terms of their subordination and marginalizacion. through using a feminist action research (far) methodology we will explore the relationship between women's employability and health in communities that represent bricish columbia's social, economic, cultural/ethnic, and geographic diversities: skidegate, fort st . .john, lumhy, and surrey. over the course of our year project, in each community we will establish and work with advisory committees, hire and train local researchers, conduct far (including a range of qualitative methods), and support action and advocacy. since the selected communities are diverse, the ways that the research unfolds will ·ary between communities. expected outcomes, such as the provision of a written report and resources, the establishment of a website for networking among the communities, and a video do.:umentary, are aimed at supporting the research participants, coalition members, and advisory conuniuces in their action efforts. p t (c) health & housing: assessing the impact of transitional housing for people living with hiv i aids currently, there is a dearth of available literature which examines supporrive housing for phas in the canadian context. using qualitative, one-on-one interviews we investigace the impact of transitional housing for phaswho have lived in the up to nine month long hastings program. our post<'r pr<·senta-t on will highlight research findings, as well as an examination of transitional housing and th<· imp;kt it has on the everyday lives of phas in canada. this research is one of two ground breaking undertakings within the province of ontario in which fife house is involved. p - (c) eating our way to justice: widening grassroots approaches to food security, the stop community food centre as a working model charles l.evkoe food hanks in north america have come co play a central role as the widespread response to growing rates of hunger. originally thought to be a short term-solution, over the last years, they have v poster sessions be · · · · d wi'thi'n society by filling the gaps in the social safety net while relieving govemcome mst tut ona ze . . . t f the ir responsibilities. dependent on corporate donations and sngmauzmg to users, food banks men so th' . · i i . are incapable of addressing the structural cause~ of ~u~ger. s pres~ntation w e~~ ore a ternanve approaches to addressing urban food security while bmldmg more sustamabl.e c~mmumt es. i:nrough the f t h st p community food centre, a toronto-based grassroots orgamzanon, a model is presented case e h'l k' b 'id · b that both responds to the emergency food needs of communities w e wor mg to. u ~ sustama le and just food system. termed, the community food centre model. (cfc), ~he s~op is worki?g to widen its approach to issues of food insecurity by combining respectful ~ rect service wit~ com~~mty ~evelop ment, social justice and environmental sustainability. through this approach, various critical discourses around hunger converge with different strategic and varied implications for a~ion. as a plac~-based organization, the stop is rooted within a geographical space and connected directly to a neighbourhood. through working to increase access to healthy food, it is active in maintaining people's dignity, building a strong and democratic community and educating for social change. connected to coalitions and alliances, the stop is also active in organizing across scales in connection with the global food justice movement. inner city shelter vicky stergiopoulos, carolyn dewa, katherine rouleau, shawn yoder, and lorne tugg introduction: in the city of toronto there are more than , hostel users each year, many with mental health and addiction issues. although shelters have responded in various ways to the health needs of their clients, evidence on the effectiveness of programs delivering mental health services to the home· less in canada has been scant. the objective of this community based research was to provide a forma· tive evaluation of a multi-agency collaborative care team providing comprehensive care for high needs clients at toronto's largest shelter for homeless men. methods: a logic model provided the framework for analysis. a chart review of clients referred over a nine month period was completed. demographic data were collected, and process and outcome indicators were identified for which data was obtained and analyzed. the two main outcome measures were mental status and housing status months after referral to the program. improvement or lack of improvement in mental status was established by chart review and team consensus. housing outcomes were determined by chart review and the hostel databases. results: of the clients referred % were single and % were unemployed. forty four percent had a psychiatric hospitalization within the previous two years. the prevalence of severe and persistent men· tal illness, alcohol and substance use disorders were %, % and % respectively. six months after referral to the program % of clients had improved mental status and % were housed. logistic regression controlling for the number of general practitioner and psychiatrist visits, presence of person· ality or substance use disorder and treatment non adherence identified two variables significantly associ· ated mental status improvement: the number of psychiatric visits (or, . ; % ci, . - . ) and treatment non adherence (or, . ; % ci, . - . ). the same two variables were associated with housing outcomes. history of forensic involvement, the presence of a personality or substance use disorder and the number of visits with a family physician were not significantly associated with either outcome. conclusions: despite the limitations in sample sire and study design, this study can yield useful informa· tion to program planners. our results suggest that strategies to improve treatment adherence and access to mental health specialists can improve outcomes for this population. although within primary care teams the appropriate collaborative care model for this population remains to be established, access to psychiatric follow up, in addition to psychiatric assessment services, may be an important component of a successful program. mount sinai hospital (msh) has become one of the pre-eminent hospitals in the world by contributing to the development of innovative approaches to effective health care and disease prevention. recently, the hospital has dedicated resources towards the development of a strategy aimed at enhancing the hospital's integration with its community partners. this approach will better serve the hospital in the current health care environment where local health integration networks have been struck to enhance and support local capacity to plan, coordinate and integrate service delivery. msh has had early success with developing partnerships. these alliances have been linked to programs serving key target populations with _estabhshe~. points of access to msh. recognizing the need to build upon these achievements to remain compe~mve, the hospital has developed a community integration strategy. at the forefront of this strategy is c.a.r.e (community advisory reference engine): the hospital's compendium of poster sessions v community partners. as a single point of access to community partner information, c.a.r.e. is more than a database. c.a.r.e. serves as the foundation for community-focused forecasting and a vehicle for inter and intra-organizational knowledge transfer. information gleaned from the catalog of community parmers can be used to prepare strategic, long-term partnership plans aimed at ensuring that a comprehensive array of services can be provided to the hospital community. c.a.r.e. also houses a permanent record of the hospital's alliances. this prevents administrative duplication and facilitates the formation of new alliances that best serve both the patient and the hospital. c.a.r.e. is not a stand-alone tool and is most powerful when combined with other aspects of the hospital's community integration strategy. it iscxpected that data from the hospital's community advisory committees and performance measurement department will also be stored alongside stakeholder details. this information can then be used to drive discussions at senior management and the board, ensuring congruence between stakeholder, patient and hospital objectives. the patient stands to benefit from this strategy. the unique, distinct point of reference to a wide array of community services provides case managers and discharge planners with the information they need to connect patients with appropriate community services. creating these linkages enhances the patient's capacity to convalesce in their homes or places of residence and fosters long-term connections to neighborhood supports. these connections can be used to assist with identifying patients' ongoing health care needs and potentially prevent readmission to hospital. introduction: recruiting high-risk drug users and sex workers for hiv-prevention research has often been hampered by limited access to hard to reach, socially stigmatized individuals. our recruitment effom have deployed ethnographic methodology to identify and target risk pockets. in particular, ethnographers have modeled their research on a street-outreach model, walking around with hiv-prevention materials and engaging in informal and structured conversations with local residents, and service providers, as well as self-identified drug users and sex workers. while such a methodology identifies people who feel comfortable engaging with outreach workers, it risks missing key connections with those who occupy the margins of even this marginal culture. methods: ethnographers formed a women's laundry group at a laundromat that had a central role as community switchboard and had previously functioned as a party location for the target population. the new manager helped the ethnographers invite women at high risk for hiv back into the space, this time as customers. during weekly laundry sessions, women initiated discussions about hiv-prevention, sexual health, and eventually, the vaccine research for which the center would be recruiting women. ra.its: the benefits of the group included reintroducing women to a familiar locale, this time as customers rather than unwelcome intruders; creating a span of time (wash and dry) to discuss issues important to me women and to gather data for future recruitment efforts; creating a location to meet women encountered during more traditional outreach research; establishing the site as a place for potential retention efforts; and supporting a local business. women who participated in the group completed a necessary household task while learning information that they could then bring back to the community, empowering them to be experts on hiv-prevention and vaccine research. some of these women now assist recruitment efforts. the challenges included keeping the group women-only, especially after lunch was provided, keeping the membership of the group focused on women at risk for hiv, and keeping the women in the group while they did their laundry. conclusion: public health educators and researchers can benefit from identifying alternate congregation sites within risk pockets to provide a comfortable space to discuss hiv prevention issues with high-risk community members. in our presentation, we will describe the context necessary for similar research, document the method's pitfalls and successes, and argue that the laundry group constitutes an ethical, respectful, community-based method for recruitment in an hiv-prevention vaccine trial. p - t (c) upgrading inner city infrastructure and services for improved environmental hygiene and health: a case of mirzapur in u.p. india madhusree mazumdar in urgency for agricultural and industrial progress to promote economic d.evelopment follo_wing independence, the government of india had neglected health promotion and given less emphasis on infrastructure to promote public health for enhanced human pro uct v_ity. ong wit r~p m astrucrure development, which has become essential if citie~ are to. act ~s harbmger.s of econ~nuc ~owth, especially after the adoption of the economic liberalization policy, importance _is a_lso ~emg g ve.n to foster environmental hygiene for preventive healthcare. the world health orga~ sat ~ is also trj:' ! g to help the government to build a lobby at the local level for the purpose by off~rmg to mrroduce_ its heal.thy city concept to improve public health conditions, so as to reduce th_e disease burden. this pape~ s a report of the efforts being made towards such a goal: the paper descr~bes ~ c~se study ?f ~ small city of india called mirzapur, located on the banks of the nver ganga, a ma or lifeline of india, m the eastern part of the state of uttar pradesh, where action for improvement began by building better sanitation and environmental infrastructure as per the ganga action plan, but continued with an effort to promote pre· ventive healthcare for overall social development through community participation in and around the city. asthma physician visits in toronto, canada tara burra, rahim moineddin, mohammad agha, and richard glazier introduction: air pollution and socio-economic status are both known to be associated with asthma in concentrated urban settings but little is known about the relationship between these factors. this study investigates socio-economic variation in ambulatory physician consultations for asthma and assesses possible effect modification of socio-economic status on the association between physician visits and ambient air pollution levels for children aged to and adults aged to in toronto, canada between and . methods: generalized additive models were used to estimate the adjusted relative risk of asthma physician visits associated with an interquartile range increase in sulphur dioxide, nitrogen dioxide, pm . , and ozone, respectively. results: a consistent socio-economic gradient in the number of physician visits was observed among children and adults and both sexes. positive associations between ambient concentrations of sul· phur dioxide, nitrogen dioxide and pm . and physician visits were observed across age and sex strata, whereas the associations with ozone were negative. the relative risk estimates for the low socio-«onomic group were not significantly greater than those for the high socio-economic group. conclusions: these findings suggest that increased ambulatory physician visits represent another component of the public health impact of exposure to urban air pollution. further, these results did not identify an age, sex, or socio-economic subgroup in which the association between physician visits and air pollution was significantly stronger than in any other population subgroup. eco-life-center (ela) in albania supports a holistic approach to justice, recognizing the environ· mental justice, social justice and economic justice depend upon and support each other. low income cit· izens and minorities suffer disproportionately from environmental hazards in the workplace, at home, and in their communities. inadequate laws, lax enforcement of existing environmental regulations, and ~ea.k penalties for infractions undermine environmental protection. in the last decade, the environmental ust ce m~ve~ent in tirana metropolis has provided a framework for identifying and exposing the links ~tween irrational development practices, disproportionate siting of toxic facilities, economic depres· s on, and a diminished quality of life in low-income communities and communities of color. the envi· ~onmental justice agenda has always been rooted in economic, racial, and social justice. tirana and the issues su.rroun~ing brow~fields redevelopment are crucial points of advocacy and activism for creating ~ubstantia~ social chan~~ m low-income communities and communities of color. we engaging intensively m prevcnnng co'.' mumnes, especially low income or minority communities, from being coerced by gov· ernmenta~ age_nc es or companies into siting hazardous materials, or accepting environmentally hazard· ous_ practices m order to create jobs. although environmental regulations do now exist to address the environmental, health, and social impacts of undesirable land uses, these regulations are difficult to poster sessions v enforce because many of these sites have been toxic-ridden for many years and investigation and cleanup of these sites can be expensive. removing health risks must be the main priority of all brown fields action plans. environmental health hazards are disproportionately concentrated in low-income communities of color. policy requirements and enforcement mechanisms to safeguard environmental health should be strengthened for all brownfields projects located in these communities. if sites are potentially endangering the health of the community, all efforts should be made for site remediation to be carried out to the highest cleanup standards possible towards the removal of this risk. the assurance of the health of the community should take precedence over any other benefits, economic or otherwise, expected to result from brownfields redevelopment. it's important to require from companies to observe a "good neighbor" policy that includes on-site visitations by a community watchdog committee, and the appointment of a neighborhood environmentalist to their board of directors in accordance with the environmental principles. vancouver - michael buzzelli, jason su, and nhu le this is the second paper of research programme concerned with the geographical patterning of environmental and population health at the urban neighbourhood scale. based on the vancouver metropolitan region, the aim is to better understand the role of neighbourhoods as epidemiological spaces where environmental and social characteristics combine as health processes and outcomes at the community and individual levels. this paper builds a cohort of commensurate neighbourhoods across all six censuses periods from to , assembles neighbourhood air pollution data (several criterion/health effects pollutants), and providing an analysis to demonstrate how air pollution systematically and consistently maps onto neighbourhood socioeconomic markers, in this case low education and lone-parent families. we conclude with a discussion of how the neighbourhood cohort can be further developed to address emergent priorities in the population and environmental health literatures, namely the need for temporally matched data, a lifecourse approach, and analyses that control for spatial scale effects. solid waste management and environment in mumbai (india) by uttam jakoji sonkamble and bairam paswan abstract: mumbi is the individual financial capital of india. the population of greater mumbai is , , and sq. km. area. the density of population , per sq. km. the dayto-day administration and rendering of public services within gr. mumbai is provided by the brihan mumbai mahanagar palika (mumbai corporation of gr. mumbai) that is a body of elected councilors on a -year team. mumcial corporation provides varies conservancy services such as street sweeping, collection of solid waste, removal and transportation, disposal of solid waste, disposal of dead bodies of animals, construction, maintance and cleaning of urinals and public sanitary conveniences. the solid waste becoming complicated due to increase in unplanned urbanization and industrialization, the environment has deteriorated significantly due to inter, intra and international migration stream to mumbai. the volume of inter state migration to mumbai is considerably high i.e. . lakh and international migrant . lakh have migrated to mumbai. present paper gives the view on solid waste management and its implications to environment and health. pollution from a wide varity of emission, such as from automobiles and industrial activities, has reached critical level in mumbai, causing respiratory, ocular, water born diseases and other health problems. sources of generation of waste are -household waste, commercial waste, institutional waste, street sweeping, silt removed from drain/nallah/cleanings. disposal of solid waste in gr. mumbai done under incineration . processing to produce organic manure. . vermi-composting . landfill the study shows that the quantity of waste disposal of through processing and conversion to organic ~anure is about - m.t. per day. the processing is done by a private agency m/s excel industries ltd. who had set up a plant at the chincholi dumping ground in western mumbai for this purpose. the corporation is also disposal a plant of its waste mainly market waste through the environment friendly, natural pro-ces~ known as vermi-composing about m.t. of market waste is disposed of in this manner at the various sites. there are four land fill sites are available and percent of the waste matter generated m mumbai is disposed of through landfill. continuous flow of migrant and increa~e in slum population is a complex barrier in the solid waste management whenever community pamc pat on work strongly than only we can achieved eco-friendly environment in mumbai. persons exposed to residential craffic have elevated races of respiratory morbidity an~ ~ortality. since poverty is an important determinant of ill-health, some h~ve argued that t~es~ assoc at ons may relate to che lower socioeconomic status of those living along ma or roads. our ob ect ve was to evaluate the association between traffic intensity at home and hospital admissions for respiratory diagnoses among montreal residents older than years. morning peak traffic estimates from the emmej montreal traffic model (motrem ) were used as an indicator of exposure to road traffic outside the homes of those hospitalised. the influence of socioeconomic status on the relationship between traffic intensity and hospital admissions for respiratory diagnoses was explored through assessment of confounding by lodging value, expressed as the dollar average over road segments. this indicator of socioeconomic status, as calculated from the montreal property assessment database, is available at a finer geographic scale than socioeconomic information accessible from the canadian census. there was an inverse relationship between traffic intensity estimates and lodging values for those hospitalised (rho - . , p vehicles during che hour morning peak), even after adjustment for lodging value (crude or . , cl % . - . ; adjusted or . , cl % . - . ). in montreal, elderly persons living along major roads are at higher risk of being hospitalised for respiratory illnesses, which appears not simply to reflect the fact that those living along major roads are at relative economic disadvantage. the paper argues that human beings ought to be at the centre of the concern for sustainable development. while acknowledging the importance of protecting natural resources and the ecosystem in order to secure long term global sustainability, the paper maintain that the proper starting point in the quest for urban sustainability in africa is the 'brown agenda' to improve che living and working environment of che people, especially che urban poor who face a more immediate environmental threat to their health and well-being. as the un-habitat has rightly observed, it is absolutely essential "to ensure that all people have a sufficient stake in the present to motivate them to take part in the struggle to secure the future for humanity.~ the human development approach calls for rethinking and broadening the narrow technical focus of conventional town planning and urban management in order to incorporate the emerging new ideas and principles of urban health and sustainability. i will examine how cities in sub-saharan africa have developed over the last fifty years; the extent to which government policies and programmes have facilitated or constrained urban growth, and the strategies needed to achieve better functioning, safer and more inclusive cities. in this regard i will explore insights from the united nations conferences of the s, especially local agenda of the rio summit, and the istanbul declaration/habitat agenda, paying particular attention to the principles of enablement, decentralization and partnership canvassed by these movements. also, i will consider the contributions of the various global initiatives especially the cities alliance for cities without slums sponsored by the world bank and other partners; che sustainable cities programme, the global campaigns for good governance and for secure tenure canvassed by unhabit at, the healthy cities programme promoted by who, and so on. the concluding section will reflect on the future of the african city; what form it will take, and how to bring about the changes needed to make the cities healthier, more productive and equitable, and better able to meet people's needs. heather jones-otazo, john clarke, donald cole, and miriam diamond urban areas, as centers of population and resource consumption, have elevated emissions and concentrations of a wide range of chemical contaminants. we have developed a modeling framework in which we first ~stimate the emissions and transport of contaminants in a city and second, use these estimates along with measured contaminant concentrations in food, to estimate the potential health risk posed by these che.micals. the latter is accomplished using risk assessment. we applied our modeling framework to consider two groups of chemical contaminants, polycyclic aromatic hydrocarbons (pah) a.nd the flame re~ardants polybrominated diphenyl ethers (pbde). pah originate from vehicles and stationary combustion sources. ~veral pah are potent carcinogens and some compounds also cause noncancer effects. pbdes are additive flame retardants used in polyurethane foams (e.g., car seats, furniture) fer sessions v and cl~ equipm~nt (e.g., compute~~· televisio~s). two out of three pbdes formulations are being voluntarily phased by mdustry due to rmng levels m human tissues and their world-wide distribution. pbdes have been .related to adv.erse neurological, developmental and reproductive effects in laboratory ijlimals. we apphed our modelmg framework to the city of toronto where we considered the southcattral area of by km that has a population of . million. for pah, local vehicle traffic and area sources contribute at least half of total pah in toronto. local contributions to pbdes range from - %, depending on the assumptions made. air concentrations of both compounds are about times higher downtown than km north of toronto. although measured pah concentrations in food date to the s, we estimate that the greatest exposure and contribution to lifetime cancer risk comes from ingestion of infant formula, which is consistent with toxicological evidence. the next greatest exposure and cancer risk are attributable to eating animal products (e.g. milk, eggs, fish). breathing downtown air contributes an additional percent to one's lifetime cancer risk. eating vegetables from a home garden localed downtown contributes negligibly to exposure and risk. for pbdes, the greatest lifetime exposure comes through breast milk (we did not have data for infant formula), followed by ingestion of dust by the toddler and infant. these results suggest strategies to mitigate exposure and health risk. p - (a) immigration and socioeconomic inequalities in cervical cancer screening in toronto, canada aisha lofters, rahim moineddin, maria creatore, mohammad agha, and richard glazier llltroduction: pap smears are recommended for cervical cancer screening from the onset of sexual activity to age . socioeconomic and ethnoracial gradients in self-reported cervical cancer screening have been documented in north america but there have been few direct measures of pap smear use among immigrants or other socially disadvantaged groups. our purpose was to investigate whether immigration and socioeconomic factors are related to cervical cancer screening in toronto, canada. methods: pap smears were identified using fee codes and laboratory codes in ontario physician service claims (ohip) for three years starting in for women age - and - . all women with any health system contact during the three years were used as the denominator. social and economic factors were derived from the canadian census for census tracts and divided into quintiles of roughly equal population. recent registrants, over % of whom are expected to be recent immigrants to canada, were identified as women who first registered for health coverage in ontario after january , . results: among , women age - and , women age - , . % and . %, rtspcctively, had pap smears within three years. low income, low education, recent immigration, visible minority and non-english language were all associated with lower rates (least advantaged quintile:most advantaged quintile rate ratios were . , . , . , . , . , respectively, p < . for all). similar gradients were found in both age groups. recent registrants comprised . % of women and had mm;h lower pap smear rates than non-recent registrants ( . % versus . % for women age - and . % versus . % for women age - ). conclnsions: pap smear rates in toronto fall well below those dictated by evidence-based practice. at the area level, immigration, visible minority, language and socioeconomic characteristics are associated with pap smear rates. recent registrants, representing a largely immigrant group, have particularly low rates. efforts to improve coverage of cervical cancer screening need to be directed to all ~omen, their providers and the health system but with special emphasis on women who recently arrived m ontario and those with social and economic disadvantage. challeges faced: a) most of the resources are now being ~pent in ~reventing the sprea.d of hiv/ aids and maintaining the lives of those already affected. b) skilled medical ~rs~nal are dymg under· mining the capacity to provide the required health care services. ~) th.e comphcat o~s of hiv/aids has complicated the treatment of other diseases e.g. tbs d) the ep dem c has led. to mcrease number of h n requiring care and support. this has further stretched the resources available for health care. orp a s d db . . i methods used on our research: . a simple community survey con ucte y our orgamzat on vo · unteers in three urban centres members of the community, workers and health care prov~ders were interviewed ... . meeting/discussions were organized in hospitals, commun.ity centre a~d with government officials ... . written questionnaires to health workers, doctors and pohcy makers m th.e health sectors. lessors learning: • the biggest-health bigger-go towards hiv/aids prevention • aids are spreading faster in those families which are poor and without education. •women are the most affected. •all health facilities are usually overcrowded with hiv/aids patients. actions needed:• community education oh how to prevent the spread of hiv/aids • hiv/aids testing need to be encouraged to detect early infections for proper medical cover. • people to eat healthy • people should avoid drugs. implications of our research: community members and civic society-introduction of home based care programs to take care of the sick who cannot get a space in the overcrowded public hospitals. prl-v a te sector private sector has established programs to support and care for the staff already affected. government provision of support to care-givers, in terms of resources and finances. training more health workers. introduction: australian prisons contain in excess of , prisoners. as in most other western countries, reliance on 'deprivation of liberty' is increasing. prisoner numbers are increasing at % per annum; incarceration of women has doubled in the last ten years. the impacts on the community are great - % of children have a parent in custody before their th birthday. for aboriginal communities, the harm is greater -aboriginal and/or torres strait islanders are incarcerated at a rate ten times higher than other australians. % of their children have a parent in custody before their th birthday. australian prisons operate under state and territory jurisdictions, there being no federal prison system. eight independent health systems, supporting the eight custodial systems, have evolved. this variability provides an unique opportunity to assess the capacity of these health providers in addressing the very high service needs of prisoners. results: five models of health service provision are identified -four of which operate in one form or another in australia: • provided by the custodial authority (queensland and western australia)• pro· vided by the health ministry through a secondary agent (south australia, the australian capital territory and tasmania) • provided through tendered contract by a private organization (victoria and northern territory) • provided by an independent health authority (new south wales) • (provided by medics as an integral component of the custodial enterprise) since the model of the independent health authority has developed in new south wales. the health needs of the prisoner population have been quantified, and attempts are being made to quantify specific health risks /benefits of incarceration. specific enquiry has been conducted into prisoner attitudes to their health care, including issues such as client information confidentiality and access to health services. specific reference will be made to: • two inmate health surveys • two inmate access surveys, and • two service demand studies. conclusions: the model of care provision, with legislative, ethical, funding and operational independence would seem provide the best opportunity to define and then respond to the health needs of prisoners. this model is being adopted in the united kingdom. better health outcomes in this high-risk group, could translate into healthier families and their communities. p - (a) lnregrated ethnic-specific health care systems: their development and role in increasing access to and quality of care for marginalized ethnic minorities joshua yang introduction: changing demographics in urban areas globally have resulted in urban health systems that are racially and ethnically homogenous relative to the patient populations they aim to serve. the resultant disparities in access to and quality of health care experienced by ethnic minority groups have been addressed by short-term, instirutional level strategies. noticeably absent, however, have been structural approaches to reducing culturally-rooted disparities in health care. the development of ethnic-specific h~alth car~ systems i~ a structural, long-term approach to reducing barriers to quality health care for eth· me mmonty populations. methods: this work is based on a qualitative study on the health care experiences of san francisco chinatown in the united states, an ethnic community with a model ethnic-specific health care infrastrucrure. using snowball sampling, interviews were conducted with key stakeholders and archival research was conducted to trace and model the developmental process that led to the current ethnic-specific health care system available to the chinese in san francisco. grounded theory was the methodology ijltd to analysis of qualitative data. the result of the study is four-stage developmental model of ethnic-specific health infrastrueture development that emerged from the data. the first stage of development is the creation of the human capital resources needed for an ethnic-specific health infrastructure, with emphasis on a bilingual and bicultural health care workforce. the second stage is the effective organization of health care resources for maximal access by constituents. the third is the strengthening and stability of those institutional forms through increased organizational capacity. integration of the ethnic-specific health care system into the mainstream health care infrastructure is the final stage of development for an ethnic-specific infrastructure. conclusion: integrated ethnic-specific health care systems are an effective, long-term strategy to address the linguistic and cultural barriers that are being faced by the spectrum of ethnic populations in urban areas, acting as culturally appropriate points of access to the mainstream health care system. the model presented is a roadmap to empower ethnic communities to act on the constraints of their health and political environments to improve their health care experiences. at a policy level, ethnic-specific health care organizations are an effective long-term strategy to increase access to care and improve qualiiy of care for marginalized ethnic groups. each stage of the model serves as a target area for policy interventions to address the access and care issues faced by culturally and linguistically diverse populations. users in baltimore md: - noya galai, gregory lucas, peter o'driscoll, david celentano, david vlahov, gregory kirk, and shruti mehta introduction: frequent use of emergency rooms (er) and hospitalizations among injection drug users (idus) has been reported and has often been attributed to lack of access to primary health care. however, there is little longitudinal data which examine health care utilization over individual drug use careers. we examined factors associated with hospitalizations, er and outpatient (op) visits among idus over years of follow-up. methods: idus were recruited through community outreach into the aids link to lntravenous experience (alive) study and followed semi-annually. , who had at least follow-up visits were included in this analysis. outcomes were self-reported episodes of hospitalizations and er/op visits in the prior six months. poisson regression was used accounting for intra-person correlation with generalized estimation equations. hits: at enrollment, % were male, % were african-american, % were hiv positive, median age was years, and median duration of drug use was years. over a total of , visits, mean individual rates of utilization were per person years (py) for hospitalizations and per py for er/op visits. adjusting for age and duration of drug use, factors significantly associated with higher rates of hospitalization included hiv infection (relative incidence [ri(, . ), female gender (ri, . ), homelessness (ri, . ), as well as not being employed, injecting at least daily, snorting heroin, havmg a regular source of health care, having health insurance and being in methadone mainte.nance treatment (mmt). similar associations were observed for er/op visits except for mmt which was not associated with er/op visits. additional factors associated with lower er/op visits were use of alcohol, crack, injecting at least daily and trading sex for drugs. % of the cohort accounted for % of total er/op visits, while % of the cohort never reported an op visit during follow-up. . . . lgbt) populations. we hypothesized that prov dmg .appomtments .for p~t ~nts w thm hours would ensure timely care, increase patient satisfaction, and improve practice eff c ency. further, we anticipated that the greatest change would occur amongst our homeless patients.. . methods: we tested an experimental introduction of advanced access scheduling (usmg a hour rule) in the primary care medical clinic. we tracked variables inclu~ing waiting ti~e fo~ next available appointment; number of patients seen; and no-show rates, for an eight week penod pnor to and post introduction of the new scheduling system. both patient and provider satisfaction were assessed using a brief survey ( questions rated on a -pt scale). results and conclusion: preliminary analyses demonstrated shorter waiting times for appointments across the clinic, decreased no-show rates, and increased clinic capacity. introduction of the advanced access scheduling also increased both patient and provider satisfaction. the new scheduling was initiated in july . quantitative analyses to measure initial and sustained changes, and to look at differential responses across populations within our clinic, are currently underway. introduction: there are three recognized approaches to linking socio-economic factors and health: use of census data, gis-based measures of accessibility/availability, and resident self-reported opinion on neighborhood conditions. this research project is primarily concerned with residents' views about their neighborhoods, identifying problems, and proposing policy changes to address them. the other two techniques will be used in future research to build a more comprehensive image of neighborhood depri· vation and health. methods: a telephone survey of london, ontario residents is currently being conducted to assess: a) community resource availability, quality, access and use, b) participation in neighborhood activities, c) perceived quality of neighborhood, d) neighborhood problems, and e) neighborhood cohesion. the survey instrument is composed of indices and scales previously validated and adapted to reflect london specifically. thirty city planning districts are used to define neighborhoods. the sample size for each neighborhood reflects the size of the planning district. responses will be compared within and across neighborhoods. data will be linked with census information to study variation across socio-eco· nomic and demographic groups. linear and gis-based methods will be used for analysis. preliminary results: the survey follows a qualitative study providing a first look at how experts involved in community resource planning and administration and city residents perceive the availability, accessibility, and quality of community resources linked to neighborhood health and wellbeing, and what are the most immediate needs that should be addressed. key-informant interviews and focus groups were used. the survey was pre-tested to ensure that the language and content reflects real experiences of city residents. the qualitative research confirmed our hypothesis that planning districts are an acceptable surrogate for neighborhood, and that the language and content of the survey is appropriate for imple· mentation in london. scales and indices showed good to excellent reliability and validity during the pre· test (cronbach's alpha from . - . ). preliminary results of the survey will be detailed at the conference. conclusions: this study will help assess where community resources are lacking or need improve· ment, thus contributing to a more effective allocation of public funds. it is also hypothesized that engaged neighborhoods with a well-developed sense of community are more likely to respond to health programs and interventions. it is hoped that this study will allow london residents to better understand the needs and problems of their neighborhoods and provide a research foundation to support local understandmg of community improvement with the goal of promoting healthy neighborhoods. p - (a) hiv positive in new york city and no outpatient care: who and why? hannah wolfe and victoria sharp introduction: there are approximately million hiv positive individuals living in the united sta!es. about. % of these know their hiy status and are enrolled in outpatient care. of the remaining yo, approx~mately half do not know their status; the other group frequently know their status but are not enrolled m any .sys~em of outpatient care. this group primarily accesses care through emergency departments. when md cated, they are admitted to hospitals, receive acute care services and then, upon poster sessions v di 'harge, disappear from the health care system until a new crisis occurs, when they return to the emergency department. as a large urban hiv center, caring for over individuals with hiv we have an active inpatient service ".'ith appr~xi~.ately discharges annually. we decided to survey our inpatients to better charactenze those md v duals who were not enrolled in any system of outpatient care. results: % of inpatients were not enrolled in regular outpatient care: % at roosevelt hospital and % at st.luke\'s hospital. substance abuse and homelessness were highly prevalent in the cohort of patients not enrolled in regular outpatient care. % of patients not in care (vs. % of those in care) were deemed in need of substance use treatment by the inpatient social worker. % of those not in care were homeless (vs. % of those in care.) patients not in care did not differ significantly from those in me in terms of age, race, or gender. patients not in care were asked "why not:" the two most frequent responses were: "i haven't really been sick before" and "i'd rather not think about my health. conclusions: this study suggests that there is an opportunity to engage these patients during their stay on the inpatient units and attempt to enroll them in outpatient care. simple referral to an hiv clinic is insufficient, particularly given the burden of homelessness and substance use in this population. efforts are currently underway to design an intervention to focus efforts on this group of patients. p .q (a) healthcare availability and accessibility in an urban area: the case of ibadan city, nigeria in oder to cater for the healthcare need of the populace, for many years after nigeria's politicl independence, empphasis was laid on the construction of teaching, general, and specialist hospital all of which were located in the urban centres. the realisation of the inadequacies of this approach in adequately meeting the healthcare needs of the people made the country to change and adopt the primary health care (phc) system in . the primary health care system which is in line with the alma ata declaration of of , wsa aimed at making health care available to as many people as possible on the basis of of equity and social justice. thus, close to two decades, nigeria has operated primary health care system as a strategy for providing health care for rural and urban dwellers. this study focusing on urban area, examimes the availabilty and accessibility of health care in one of nigeria's urban centre, ibadan city to be specific. this is done within the contest of the country's national heath policy of which pimary health care is the main thrust. the study also offers necessary suggestion for policy consideration. in spite of the accessibility to services provided by educated and trained midwifes in many parts of fars province (iran) there are still some deliveries conducted by untrained traditional birth attendants in rural parts of the province. as a result, a considerable proportion of deliveries are conducted under a higher risk due to unauthorised and uneducated attendants. this study has conducted to reveal the pro· portion of deliveries with un-authorized attendants and some spatial and social factors affecting the selection of delivery attendants. method: this study using a case control design compared some potentially effective parameters indud· ing: spatial, social and educational factors of mothers with deliveries attended by traditional midwifes (n= ) with those assisted by educated and trained midwifes (n= ). the mothers interviewed in our study were selected from rural areas using a cluster sampling method considering each village as a cluster. results: more than % of deliveries in the rural area were assisted by traditional midwifes. there are significant direct relationship between asking a traditional birth attendant for delivery and mother age, the number of previous deliveries and distance to a health facility provided for delivery. significant inverse relationships were found between mother's education and ability to use a vehicle to get to the facilities. conclusion: despite the accessibility of mothers to educated birth attendants and health facilities (according to the government health standards), some mothers still tend to ask traditional birth attendants for help. this is partly because of unrealistic definition of accessibility. the other considerable point is the preference of the traditional attendants for older and less educated mothers showing the necessity of changing theirs knowledge and attitude to understand the risks of deliveries attended by traditional and un-educated midwifes. p - (a) identification and optimization of service patterns provided by assertive community treatment teams in a major urban setting: preliminary findings &om toronto, canada jonathan weyman, peter gozdyra, margaret gehrs, daniela sota, and richard glazier objective: assertive community treatment (act) teams are financed by the ontario ministry of health and long-term care (mohltc) and are mandated to provide treatment, rehabilitation and support services in the community to people with severe and persistent mental illness. there are such teams located in various regions across the city of toronto conducting home visits - times per week to each of their approximately respective clients. each team consists of multidisciplinary health professionals who assist clients to identify their needs, establish goals and work toward them. due to complex referral patterns, the need for service continuity and the locations of supportive housing, clients of any one team are often found scattered across the city which increases home visit travel times and decreases efficiency of service provision. this project examines the locations of clients in relation to the home bases of all act teams and identifies options for overcoming the geographical challenges which arise in a large urban setting. methods: using geographic information systems (gis) we geocoded all client and act agency addresses and depicted them on location maps. at a later stage using spatial methods of network analysis we plan to calculate average travel rimes for each act team, propose optimization of catchment areas and assess potential travel time savings. resnlts: initial results show a substantial scattering of clients from several act teams and substan· rial overlap of visit travel routes for most teams. conclusions: reallocation of catchment areas and optimization of act teams' travel patterns should lead to substantial savings in travel times, increased service efficiency and better utilization of resourc_~· ~e l'<!tenri~i modifications to catchment areas must be conducted with appropriate attention to specific clients servtce needs, service continuity and applicable regulations by the mohl tc. venice lido is a popular island within and outside italy because it hosts the international cinema festival yearly. only few people remember the island for its hospital, which, in the fifties, was one of the most important hospitals in italy and in europe, being a modern center for wind-, sun-and thermal-therapy. since the sixties, its fame became to drop away, since its structure was no longer adequate for the evolving medicine science. at the end of the seventies all the wards were moved into a new big building in the same area. at present the hospital is made up by about forty 'pavilions' (mostly partially used or empty) and a big building, disseminated in a hectares area, on the sea front, on the m long beach. the aim of my research is to suggest a realistic solution, sustainable on the functional use of the area according to basic local needs and economically realizable. i used a philological and multi-disciplinary method, more in detail: -from historical documents, i found what was the very first call of the property and how it adapted to the needs of the demographic development and the sanitary supply over time; -by contacting some operators from different fields, i realized which functions were suitable to the buildings in existence, to the population's needs and to the present sanitary supply. moreover the planning idea considers: -the debate going on between local people who strongly want to preserve the property, and die ones who want to renew it by different new opportunities; and -the regional sanitary politics, aiming at rationalizing the regional hospitals dislocation, and the budget needs. this plan analyzes and proposes some new alternative solutions to satisfy different needs. the different activities will be dealt out and the environmental fall will be limited as much as possible. after having analyzed its basic call, considered its environmental peculiarities and its position, verified the emerging needs of the local population, the plan proposes different activities: the hospital; the social-rehabilitation center; the elderly house; the thermal center; the residential center; and other activities. such a plan wants to share in the solution of a basic problem by giving architectonic and functional dignity to an historical completely degraded area and by starting again a social-economical broken off process, by bringing in venice lido some fresh necessary elements for its so wished new throw. p - (c) dilemma of free health care in spokane, wa david bunting introduction: the paper reports on the activities of project access spokane [pas], a physician sponsored initiative to provide uncompensated health care to low income, uninsured residents of spokane county wa. program providers included all county hospitals, over physicians, other medical professionals, and specialized clinics. each prescription requires only a $ co-payment. sponsored and administered by the county medical society, pas is funded by local and national foundations, private corporations, municipalities, civic organizations and individuals. method: the paper is based on a first year assessment report funded by pas, using hcfa [health care financing administration] insurance claim data documenting utilization rates, disease categories and donated charge information and patient cares [centralized applications, referrals and enrollment status) data. results: while essentially free for enrollees, the program involved real costs. an administrative organization to refer over patients to any of over providers had to be developed and staffed, using both paid and unpaid personnel. methods to identify potential patients and veri.fy eligibility. had to ~devised. patient appointments and transportation had to be scheduled and monitored. pu~hc relanons, provider solicitations and fundraising activities were continuous. information requirements regarding program operation were also significant. data reporting the volume. ~nd value of dona~ed medical services were necessary to demonstrate accomplishments and attr~ct addmon~l support. providers required assurances their contributions were both significant and eqmtable. funding sources sought evidence that their support had important consequences. however, generating this ~~ta proved difficult. many providers failed to submit appropriate insurance claims forms because .of a~dmonal donated effort and administrative cost, thereby not only reducing their own apparent conmbut ons but also the overall significance of the program. conclusions: during its initial year, the estimated cost to deliver free health care was ~bout per enrollee. the lesson is that without an elaborate administrative structure and record keeping s.yst~~· efforts to provide free health care probably will fail. eligible enrollees c~n not be ~parated from in~hgi ble ones, care will not be accessed or delivered in an efficient manner, neither fundmg nor ~upport "". be offered without evidence of tangible benefits, and providers will withdraw if they perceive mequ table tteannent. v p - s (c) mobility in prostitution and the impact of health therese van der helm and henk sulman poster sessions introduction: many of the estimated . commer~ial ~ex wor~ers (c~w)in a'.' ~terdam ~~me from developing countries and eastern europe. to gain ins~ght mto their workmg and_ hvmg condinons the intermediary project (ip) at the municipal health serv ~e _contacts these women via ?utreach work on regular basis. since the new brothel law in october s ~troduc~d, ~sw ~rom outside the eu and who have no dutch residence permit are not allowed to work m prost tut n. smee then, many of these csw therefore have gone "underground." the consequences of the new law in the netherlands will be discussed with regard to the accessibility of csw and their risk for stl/hiv acquisition and unplanned pregnancies. methods: topics during outreach work are the interventions to increase the knowledge of safe sex and birth control for csw. written information is handed out in relevant languages and with addresses of health and social services. in conversations with the women, it appeared that many are not aware of these services. to provide easier access to health care for women, staff of the ip carries out free sti control csw working places, in windows brothels and sex houses. also, women are offered vaccination against hepatitis b (hbv). results: from january till july we approached csw for first contact. one third was dutch; others were from developing countries, other eu countries and eastern europe. sti consul· rations were done among non-iv drug using sex workers, of whom % was dutch. of these, % was diagnosed with syphilis, % with gonorrhea, and % with chlamydia. of women tested for hiv, none were infected. due to the high turnover of csw in .brothels, most wnmen were tested only once. among csw tested for hbv -of whom one third is dutch - % had antibodies for hbv, were carrier of hbv, most of whom came from hbv endemic areas. conclusions: sti control and hbv vaccination in brothels is an important support in health care. our findings suggest that csw do not play an important role in the transmission of sti. many csw are highly mobile and often not aware of the existing health and social services. continuous outreach is important to remain in contact with this mobile population. regulations in the new brothel law should not hamper contacts with (illegal) csw. heart disease (cho) is projected to become the leading cause of death. studies conducted in europe and the united states have proven a higher rate of cho in south asians who have migrated from south asia, most notably india, pakistan and bangladesh. approximately % of all heart attacks among south asian men occur under the age of ; % of them occur under the age of -unheard of in any other population. associated risk factors such as diabetes, high blood pressure and cholesterol are also com· mon in this group. the population of south asians residing in nyc has more than doubled over the past decade to over , , the majority being young, working-class and with limited health care access. many south asian men are employed as taxi drivers ( out of nyc taxi drivers are from south asial, working daily hour plus shifts. methods: acknowledging that this vulnerable, at-risk group was unavailable for outreach through conventional venues, three of the hospitals of the new york city health and hospital corporation, (elmhurst, queens and bellevue) conducted a one day outreach effort at nyc's jfk international air· ~rt's taxi holdin~ ar~a, ~here over one thousand taxis regularly assemble. bringing an outreach event directly to the taxi dnvers workplace, a tent was set up where cardiovascular-related health screenings, in~luding bl~ pressure, sugar, cholesterol, body mass index (bmi), were provided. results were shared with and explamed to the drivers and each participant received a south asian health education brochure. a total of taxi drivers who identified as south asian were involved. rau/ts: participants were all male, ranging from to years; mean age, . . screenings revealed % hypertensive; % had cholesterols over ; % blood glucose over ; % had a bmi greater than . conc~on: a unique outreach activity, adapting to logistical, occupational limitations, is pre· se~ted. on-site f~back and explanation of results, reiterating and reinforcing the concern that south asia~. men are at mcreased danger for early coronary heart disease, and the dissemination of a culturally sensmve and r~levant brochure, may heighten awareness of prevailing cardiac risk factors in this immi· grant community. p - (c) the community-hospital integration program framework: community-hospital panoenhips to improve the population's health john stevenson, richard blickstead, ann-marie marcolin, and sandi kendal v introduction: st. josephs health centre is a catholic community teaching hospital located in the heart of southwest toronto. st. joseph\'s was founded from a community-expressed need for hospital services, and since then has stayed committed to fostering a healthy community through collaboration and parmership. st. joseph's has developed an innovative model, the community-hospital integration program (chip), to strengthen st. joseph's partnerships with community stakeholders, and facilitates the building of links between community needs, service provision, and public policy outcomes to improve the health and wellness of the diverse neighbourhoods they together serve. methods: development of the chip framework st. joseph's health centre developed the chip framework through a multidisciplinary approach that included extensive international literature reviews, consultations, and key informant interviews with community service agencies and academics. to ensure active community voice, st. joseph's has hosted a number of community consultations including a community outreach forum attended by over ninety representatives from community partners. results: the chip framework the chip framework aims to improve the health and wellness of the urban communities served by st. josephs health centre through four intersecting pillars: • raising community voices provides an infrastructure and process that supports community stakeholder input into health care service planning, decision-making, and delivery by the hospital and across the continuum of care; • sharing reciprocal capacity promotes healthy communities through the sharing of our intellectual and physical capacity with our community partners; • cultivating integration initiatives facilitates vertical, horizontal, and intersectoral integration initiatives in support of community-identified needs and gaps; and • facilitating healthy exchange develops best practices in community integration through community-based research, and facilitates community voice in informing public policy. the chip framework drives the complex inter-relationships between community-hospital engagement, reciprocal capacity-building, integration initiatives, and community-based research and evaluation, to create an interconnected network of health care services. the fluidity and simplicity of this framework, and its dedication to balancing community needs and hospital mandate, posits the st. josephs health centre's chip model as an integral component in building healthy and thriving communities. p - (c) home based care promotion: improving acess to quality services and livelihood in the face of aids home based care is a service provided to persons affected/living with hiv/aids, a menu of care/support services at home/community. it is a prominent alternative approach. in uganda, hospital bed ocupacny is high, patient health care worker ratio deteriorating. empowering communities offers solutions to the problems; adressing cost, effectiveness of care. hiv/aids demands changes in attitudes, behaviour, approaches which is enhanced in home/community settings. for example art requires high levels of adherecnce, which medical workers have vety little opportunity to enforce. it also demands other support mechanisims in terms of nutrition, personal displine, etc which work best in stigma free environments. hence the relevance of home based care. this paper highlights the gaps that call for increased action in terms of home based care, examples of whre it has worked key challenges and recommendations for the future. p - (c) health care for one ... health care for alli katharina kovacs burns introduction: at the surface, it appears that every person in canada _has. ~ccess to a publicly funded health care system. those living in urban centers should have the best ava l~b hty, chmce, and access to a variety of health care services because of the distribution of health care services, fac lmes, and health professionals in concentrated in urban centers. this is not true for everyone -people with low income or who are homeless experience the challenges of social exclusion and being marginalized: there are many factors at play making it difficult for the latter group of people to access health care. service they need,.when they need them. health care is not as accessible or inclusive as intended. the quesuon to be explore.cl ~: if health care is available and accessible to one person, what makes it not available to all people? the ~ gmfic~nce of having marginalized people accessing health care and other services includes e~hanced quality of hfe and decreased risks associated with being homeless, and cost savings in ion~ ter~ w rh acute health care. methodology: community-based participatory research is applied m a case study on health care access and challenges experienced by low income and homeless people in one urban centre, edmonton, edmonton, and their challenges. the data is being gathered and ana_lyzed usmg basic m x~d methods. results: the results will focus on how services can be more mtegrated and accessible to all people with low income and who are homeless. there will also be discussion about specific perceptions of not only the service providers but also of people with low income an~ who are homeless~ and vario~s decision makers. the results will be compared to the literature regardmg health care services access mother urban centers in canada and elsewhere. conclusions: recommendations will need to address social exclusion and other factors which can make health care and other services more available to all people in the community. the implications for health care will also be discussed. additional information will be gathered in the next phases of the study to develop a community services access model. p - (c) availability and access exemplified: a case study beth hayhoe and ruth ewert introduction: access to health care in canada requires either the correct documentation or money. street youth have neither. in addition, health services in canada are designed by adults for adults. youth in general are often wary of having trust in adults with respect to their health concerns and frequently feel misunderstood. street youth are even more mistrustful of adults and public organizations, making their contact with health care professionals minimal. this combined with their risky behaviours and dangerous environment creates a population at risk for numerous health issues but with no place to have them investi· gated. at our non-government, not for profit health service designed specifically to provide a broad range of health care to street youth, professional services are provided almost entirely by volunteers. methods: using a retrospective analysis of the years of data gathered from this organization and reviewing the initial reasons gathered from youth about their needs, the success of the health centre was examined. results: all the things youth had listed as being important in a health centre have been implemented, and even more things have been added to improve the breadth and quality of services offered. the use of the health centre has increased by more than six times since its opening in . in addition, tens of thousands of visits have been paid to the health centre, costing the government and taxpayers nothing. as far as we know there is nothing else in canada that offers so many diverse and innovative services to youth in need. conclusion: it is clear from this case, that health care targeted at the needs of specific disadvan· taged populations can successfully provide them with appropriate health care. a model of accessible health care for marginalized populations can easily be developed for high impact and low cost from this successful case. toronto is one of the most ethno-racially diverse cities in the world of the estimated , , toronto residents, % ( , ) live in scarborough population growth in scarborough is faster than toronto. scarborough's population increased by % from to while toronto increased only by %. toronto's population is projected to increase by % ( ) in while scarbor· ough's will increase by %. (census canada ) low income, pove;ty, seniors, hidden homeless, new~omers to canada, the uninsured, are just a few of the issues concerning health care in our community. health care needs in scarborough are greatly impacted by diversity of ethnic and racial groups, poverty and settlement issues. this paper will share how the scarborough hospital (tsh) an urb~n communir_y hospital cares f~~ it~ community. tsh recognizes: •the changing community• b_arriers t~ accessing care • lnequalmes m health care the hospital in caring for its community pro· v ~es services that '!'e~e cu~turally, racially, and linguistically sensitive to our community. the paper will share the hospitals unique program on access and equity. the paper will share the needs in scar· borough and tsh's response to these needs: working in partnership with the local health committee, i:ne scarborough homeless co.mminee, the scarborough network of immigrant services organiza· nons a~d others. :' e paper will also share the many initiatives this urban community hospital has taken viz. community and home programs in service areas such as mental health, haemodialysis day care, t~~ home oxyg~n program, the palliative at-home program, and above all support for the volunteer clinic for the uninsured. j"'" tllu:lion: in canada's universal health care system it is generally assumed that everyone has equal access to health care. however, some immigrant groups in canada have historically been uninswed. these groups include failed refugee claimants, those overstaying their visas, and new immigrants in transition who are waiting to become eligible for health insurance. some estimates have suggested that at the present time there may be as many as one hundred thousand undocumented and thus uninsured immigrants in toronto alone. understandably, information on the characteristics of this marginalized population is very limited, since undocumented immigrants tend to have little contact with formal institutions. knowledge of the demographic characteristics of this population may aid in the development of health and social programs to better identify and meet the needs of undocumented immigrants in toronto. we conducted a review of all undocumented, uninsured patients, years of age or older at access alliance multicultural community health centre (aamchc) between and . demographic information such as age, gender, preferred language, length of time living in canada, selfreported education level and household income were recorded. rmdts: % of all adult patients at access alliance were undocumented and uninsured. % were under years of age (with a median age of years), % were women and only % spoke english. this group lived in canada for an average period of . years before they were first seen at aamchc. % of undocumented clients reported having completed at least a secondary or post-secondary education. % had self-reported household incomes of less than , $/year, while % of households reported earning less than $ , /year. the mean income per person in an average household was $/month. conchuions: uninsured individuals at aamchc were predominantly young females with limited knowledge of the english language. despite having attained a high level of education most were living well below the poverty line. recognition of these characteristics may assist in the development of health and social programs that are better adapted to meet the needs of undocumented immigrants. p - (c) sharing expertise: a role for the hospital lactation consultant in the community. badrgrmuul: st. michael's hospital is a tertiary care hospital that serves a large inner city population in downtown toronto. in order to provide care to this population, the hospital has developed a number of unique outreach roles. one such role was developed to work with pregnant and breastfeeding women living in regent park, a social housing complex located near the hospital. the population of regent park includes new immigrants, refugees and the socially disadvantaged. approach: the outreach lactation consultant provides care, as part of the canada prenatal nutrition program, in the community prenatally, in the hospital during their inpatient stay and postnatally when they return to the community. the continuity of care enhances the probability of long term successful breastfeeding. aside from the health benefits of breastmilk, breastfeeding is especially important for women who are financially needy and must depend on food banks for formula. . . lason learned: aher two years of partnership, the relationship between the an-hospital ~stpar tum experience for breastfeeding mothers and the community postpartum support, the breastfeeding rate ~thin this community is high. the professional support and visibility of the : ctation consultant, both m the hospital and in the community, contributes to the support of breastfee~m~.. . in light of ongoing funding constraints, this ha son between hospital and community could be at risk and discontinued. in light of the benefits to the mother/baby dyad, the lactation consultant as a community partner in the canada prenatal nutrition program should be safeguarded. . lldpodiu:tion: although the importance of adequate health care in pregna~cy is well recognised, ethnic disparities in utilization of prenatal care still exist in many western coun~~es. a fun~amental factor in these disparities may be language proficiency, as it influences women's ab hty. to ob~m and understand health information, to find the way in the health care system and to communicate with health care v poster sessions providers. we investigated the role of language proficiency in use and knowledge of folic acid as aspect of prenatal care in an urban multi-ethnic pregnancy c?hort. . . design: prospective cohort study. setting and parnc pants: amsterdam ~regnant women attending obstetric care providers for their first antenatal visit (n= ). country of birth defined ethnicity: the netherlands, surinam, antilles, turkey, morocco, ghana, other non-~est~m (nw) and other western (w) country. main outcome measures: knowledge about and use of.fohc a~d (fa) supplements in pregnancy, and determinants of these in diffe~~t ethnic ~~ups. deterrrunants mcl~ded age, ed~ tion, parity, pregnancy intention and dutch prof c ency. stansncs: ~ to co~p~re e~c groups, stranfied logistic regression (forward stepwise method) to explore determmants "'.'thm ethmc groups .. use of fa supplements was significantly lower among ghanaian, moroccan, turkish and other nw women ( %to %) than among dutch ( %) or other w women ( %). use amongsurinames and antillean women was intermediate ( %and %). ethnic differences in fa knowledge were similar. knowledge was the strongest determinant of use in all ethnic groups, with odds ratios (ors) ranging from . to . . language proficiency was the strongest determi~a~t of kno~ledge in ethnic groups with a mother tongue different from dutch (ors good vs. low proficiency ranging from . ro . ). educational level had a modifying role, as shown by an interaction effect between education and language proficiency in the nw group. here, the odds of having fa knowledge given a high education and good dutch proficiency was times the odds given a good proficiency but low education. conclusions: appropriate periconceptional use of folic acid supplements in non-western ethnic groups is low, reflecting an absence of knowledge that is largely determined by the inability to speak and understand the language of the habitual country. tailored interventions using communication channels most likely to address (pregnant) women from ethnic minority groups are necessary. apan from specific interventions, our results are in support of strong incentives on language education despite current political debate. introduction: recent research suggests living in an economically disadvantaged neighborhood is asso· ciated with decreased likelihood of undergoing mammography and increased risk of late-stage breast can· cer diagnosis. long distances and travel times to facilities offering low-or no-cost mammography may be imponant barriers to adherence to mammography screening recommendations for residents of economically disadvantaged neighborhoods. the purpose of this study was to examine whether facilities providing low-and no-cost screening mammography were less spatially accessible in low-income neighborhoods in chicago, and the extent to which the relationship between neighborhood income and the spatial accessibility of facilities varied by the proponion of african-american residents in the neighborhood. methods: the sample consisted of chicago neighborhoods. for each neighborhood, we con· structed three measures of the spatial accessibility of facilities: street network distance to the nearest facility, public transportation travel time to the nearest facility, and shortest automobile travel time to a facility. using decennial census data, we characterized the neighborhoods according to proportion of residents with incomes below the poverty line, proportion of residents in each of four raciavethnic groups (african-american, latino, white, and other), and population density. we used ordinary least squares (ols) and spatial exogenous lag regression to examine relationships. model estimated the relationship between neighborhood poverty and the spatial accessibility of facilities, adjusting for raciaveth· nic composition and population density. model added a multiplicative interaction term between neighborhood poverty and african-american. restllts: we identified deven facilities that provided low-or no-cost screening mammography to chicago residents in . we found that the distance and travel times via automobile and public trans· portation to facilities generally decreased as neighborhood poveny increased. however, we also found that the ~egative associations between neighborhood poverty and two of the spatial accessibility mea· sures -distance and public transportation travel time -were less strong in neighborhoods with the highest proponions of african-american residents. among neighborhoods in the highest tertile for poveny, th~ mean distance and mean public transportation travel time to facilities were over twice as long in neighborhoods in the highest tertile than in those in the lowest tenile of african-american residents. . ~ persistent socioeconomic and racial/ethnic disparities in breast cancer stage at diagno-s ~nd su~ val suggest that ensuring an equitable distribution of affordable mammography is a worth-w~e policy .goal. the ~~dy sugges~ that ~ture investigations should consider both neighborhood soc oecono d c charactensbes and rac avethmc composition when examining the spatial distribution of health resources. , ) . epidemiological data suggest tha~ hiv prevalence among msm is over % in some metropolitan cities, such .as beijing (ibid.). due to widespread homophobia in chinese society, however, this population remains invisible within current health/social services. lack of research on sexuality, specifically homosexuality, has impaired our understanding of health and health practices of chinese msm. focusing on the illness experiences of chinese msm with hiv/aids, this paper explores the socio-cultural impacts of hiv/ aids on this group. the data used for this paper were collected through semi-constructed in-depth face-toiace interviews with adult plwhas (including msm) in beijing, china. with the permission of the participants, the interviews were audio-taped or recorded in notes. the transcribed interviews and interview notes were analyzed by using n-vivo, a software program for qualitative data analysis. this phenomenological study aimed to understand the experiences chinese plwhas (including msm) from their own perspectives. results: it is found that the illness experiences of chinese msm with hiv/aids are profoundly shaped by the socio-cultural meanings of homosexuality, which are further complicated by the dominant discourses on hiv/aids in china. at a macro level, homophobia in the larger society has decreased the capability of this group to respond to this epidemic in a more efficient way. at a meso level, aids-phobia within the chinese msm circuits has prevented this group from openly confronting this disease and offering support to those who are already affected by it. at a micro level, however, these hiv-infected/ affected msm have tried their best to locate spaces to live and to construct hope for their future lives despite various barriers within family, community, and the larger society. this study suggests that facilitating chinese msm's response to the aids crisis urgently requires bridging awareness, commitment, knowledge and resources both within and without this group. it also illustrates the importance of understanding homosexuality in the local context of hiv i aids, which will be helpful for developing culturally sensitive hiv/aids programs for this population on the community, national and international levels. introduction: having a regular family doctor (rfd) is known to be positively correlated with a good medical follow up, including access to preventive and/or chronic care. inversely, a lack of primary care may lead to high rates of avoidable hospitalizations, especially among poor people and/or in underserved neighbourhoods. in such a matter, a recent comparative study showed that paris was better ranged than other cities, such as nyc, tokyo or london. nevertheless, despite a quasi universal health insurance and a high density of general practitioners, a noticeable fraction of the paris population does not have any regular physician and we aimed to understand who they are and for what reasons rhey don't have any rfd. mdbods: cross sectional population survey among a random sample of households in ~nderpriv ileged neighbourhoods in paris inner city, performed in , using a face-to-face quest nna re collecr- ng more than social and health characteristics. ruults: a quarter ( . %) of rhe study popularion did not have any rfd. this proporrion was iignificantly higher among male (or= . , %ci = [ . - . ), younger (e.g. or - /> .s l _= ._oo, " .ci = ( . - . )), and/or unemployed (or = . , %ci = ij . - . _ people. in multtvanate analysis, after a full adjustment on gender, age, health status, health insura~ce, income, occupat n and tducation level, we observed significant associations between having no rfd and: ~arrtal and_ pare~t hood status (e.g. or single no kids/in couple+kids = . , %ci = ( . - . ()~ quality of relattonsh ps with neighbours (or bad/good= . , %ci = [ . - . )), and length of residence m the neighbourhood (with a dose/effect statistical relationship). . co clusion: gender, age, employment status, mariral and parenthood stat~s as well as ~e gh bourhood anchorage seem to be major predictors of having a rfd, even when um.versa! health i~sur ance has reduced most of financial barriers. in urban contexts, where residential migrattons and single lift (or family ruptures) are frequent, specific information may be conducted to encourage people to ket rfd. :tu~y tries to assess the health effects and costs and also analyse the availability and accessibility to health care for poor. . methods: data for this study was collected by a survey on households of the local community living near the factories and households where radiation hazard w~s n?~ present. ~~art from mor· bidity status and health expenditure, data was collected ~n access, a~ail~b .hty and eff c ency of healrh care. a discriminant analysis was done to identify the vanables that d scnmmate between the study and control group households in terms of health care pattern. a contingent valuation survey was also undertaken among the study group to find out the factors affecting their willingness to pay for health insurance and was analysed using logit model. results: the health costs and indebtedness in families of the study group was high as compared to control group households and this was mainly due to high health expenditure. the discriminant analysis showed that expenditure incurred by private hospital inpatient and outpatient expenditure were significant variables, which discriminated between the two types of households. the logit analysis showed !hat variables like indebtedness of households, better health care and presence of radiation induced illnesses were significant factors influencing willingness to pay for health insurance. the study showed that study group households were dependent on private sector to get better health care and there were problems with access and availability at the public sector. conclusion: the study found out that the quality of life of the local community is poor due to health effects of radiation and the burden of radiation induced illnesses are so high for them. there is an urgent need for government intervention in this matter. there is also a need for the public sector to be efficient to cater to the needs of the poor. a health insurance or other forms of support to these households will improve the quality for health care services, better and fast access to health care facilities and reduces the financial burden of the local fishing community. the prevalence of substance abuse is an increasing problem among low-income urban women in puerto rico. latina access to treatment may play an important role in remission from substance abuse. little is known, however, about latinas' access to drug treatment. further, the role of social capital in substance abuse treatment utilization is unknown. this study examines the relative roles of social capital and other factors in obtaining substance abuse treatment, in a three-wave longitudinal study of women ages - living in high-risk urban areas of puerto rico, the inner city latina drug using study (icldus). social capital is measured at the individual level and includes variables from social support and networks, familism, physical environment, and religion instruments of the icdus. the study also elucidates the role of treatment received during the study in bringing about changes in social capital. the theoretical framework used in exploring the utilization of substance abuse treatment is the social support approach to social capital. the research addresses three main questions: ( t) does social capital predict parti~ipating in treatment programs? ( ) does participation in drug treatment programs increase social capital?, and ( ) is there a significant difference among treatment modalities in affecting change in ~ial capital? the findings revealed no significant association between levels of social capital and gettmg treatment. also, women who received drug treatment did not increase their levels of social capital. the findings, however, revealed a number of significant predictors of social capital and receiving drug ~buse treatment. predictors of social capital at wave iii include employment status, total monthly mcoi:rie, and baseline social capital. predictors of receiving drug abuse treatment include perception of physical health and total amount of money spent on drugs. other different variables were associated to treatment receipt prior to the icldus study. no significant difference in changes of social capital was found among users of different treatment modalities. this research represents an initial attempt to elucidate the two-way relationship between social capital and substance abuse treatment. more work is necessary to unden~nd. ~e role of political forces that promote social inequalities in creating drug abuse problems and ava lab hty of treatment; the relationship between the benefits provided by current treatment poster sessions v sctrings and treatment-seeking behaviors; the paths of recovery; and the efficacy and effectiveness of the trtaanent. and alejandro jadad health professionals in urban centres must meet the challenge of providing equitable care to a population with diverse needs and abilities to access and use available services. within the canadian health care system, providers are time-pressured and ill-equipped to deal with patients who face barriers of poverty, literacy, language, culture and social isolation. directing patients to needed supportive care services is even more difficult than providing them with appropriate technical care. a large proportion of the population do not have equitable access to services and face major problems navigating complex systems. new approaches are needed to bridge across diverse populations and reach out to underserved patients most in need. the objective of this project was to develop an innovative program to help underserved cancer patients access, understand and use needed health and social services. it implemented and evaluated, a pilot intervention employing trained 'personal health coaches' to assist underserved patients from a variety of ethno-linguistic, socio economic and educational backgrounds to meet their supportive cancer care needs. the intervention was tested with a group of underserved cancer patients at the princess margaret hospital, toronto. personal coaches helped patients identify needs, access information, and use supportive care services. triangulation was used to compare and contrast multiple sources of quantitative and qualitative evaluation data provided by patients, personal health coaches, and health care providers to assess needs, barriers and the effectiveness of the coach program. many patients faced multiple barriers and had complex unmet needs. barriers of poverty and language were the easiest to detect. a formal, systematic method to identify and meet supportive care needs was not in place at the hospital. however, when patients were referred to the program, an overwhelming majority of participants were highly satisfied with the intervention. the service also appeared to have important implications for improved technical health care by ensuring attendance at appointments, arranging transportation and translation services, encouraging adherence to therapy and mitigating financial hardship -using existing community services. this intervention identified a new approach that was effective in helping very needy patients navigate health and social services systems. such programs hold potential to improve both emotional and physical health out· comes. since assistance from a coach at the right time can prevent crises, it can create efficiencies in the health system. the successful use of individuals who were not licensed health professionals for this purpose has implications for health manpower planning. needle exchange programs (neps) have been distributing harm reduction materials in toronto since . counterfit harm reduction program is a small project operated out of a community health centre in south-east toronto. the project is operated by a single full-time coordinator, one pan-rime mobile outreach worker and two peers who work a few hours each week. all of counterfit's staff, peers, and volunteers identify themselves as active illicit drug users. yet the program dis~rib utes more needles and safer crack using kits and serves more illicit drug u~rs t~an the comb ~e~ number of all neps in toronto. this presentation will discuss the reasons behind this success, .s~ f cally the extended hours of operation, delivery models, and the inclusion of an. extremely marg ~ahzed community in all aspects of program design, implementation and eva.luat ?n. ~ounterfit was recently evaluated by drs. peggy milson and carol strike, two leading ep dem olog st and researchers in the hiv and nep fields in toronto and below are some of their findings: "the program has experienced considerable success in delivering a high quality, accessible and well-used program .... the pro· gram has allowed (service users) to become active participants in providing. services to others and has resulted in true community development in the best sense. " ... counterf t has ~~n verr succe~sful attracting and retaining clients, developing an effective peer-based model an.d assisting chen~s ~ th a vast range of issues .... the program has become a model for harm red~ctmn progr~ms withm the province of ontario and beyond." in june , the association of ?ntano co~mumty heal~~ <:en· ires recognized counterfit's acheivements with the excellence m community health initiatives award. in kenya, health outcomes and the performance of government health service~ have det~riorated since the late s, trends which coincide with a period of severe resource constramts necessitated by macro-economic stabilization measures after the extreme neo-liberalism of the s. when the govern· ment withdrew from direct service provision as reform trends and donor advocacy suggested, how does it perform its new indirect role of managing relations with new direct health services providers in terms of regulating, enabling, and managing relations with these health services providers? in this paper therefore, we seek to investigate how healthcare access and availability in the slums of nairobi has been impacted upon by the government's withdrawal from direct health care provision. the methodology involved col· leering primary data by conducting field visits to health institutions located in the slum areas of kibera and korogocho in nairobi. purposive random sampling was utilized in this study because this sampling technique allowed the researcher(s) to select those health care seekers and providers who had the required information with respect to the objectives of the study. in-depth interviews using a semi-structured ques· tionnaire were administered ro key informants in health care institutions. this sought to explore ways in which the government and the private sector had responded and addressed in practical terms to new demands of health care provision following the structural adjustment programmes of the s. this was complemented by secondary literature review of publications and records of key governmental, bilateral and multilateral development partners in nairobi. the study notes a number of weaknesses especially of kenya's ministry of health to perform its expected roles such as managing user fee revenue and financial sustainability of health insurance systems. this changing face of health services provision in kenya there· fore creates a complex situation, which demands greater understanding of the roles of competition and choice, regulatory structures and models of financing in shaving the evolution of health services. we rec· ommend that the introduction of user fees, decentralization of service provision and contracting-out of non-clinical to private and voluntary agencies require a new management culture, and new and clear insri· tutional relationships. experience with private sector involvement in health projects underlines the need not only for innovative financial structures to deal with a multitude of contractual, political, market and risks, but also building credible structures to ensure that health services projects are environmentally responsive, socially sensitive, economically viable, and politically feasible. purpose: the purpose of this study is to examine the status of mammography screening utilization and its predictors among muslim women living in southern california. methods: we conducted a cross-sectional study that included women aged ::!: years. we col· leered data using a questionnaire in the primary language of the subjects. the questionnaire included questions on demography; practices of breast self-examination (bse) and clinical breast examination (cbe); utilization of mammography; and family history of breast cancer. bivariate and multiple logistic regression analyses were performed to estimate the odds ratios of mammography use as a function of demographic and other predictor variables. . results: among the women, % were married, % were - years old, and % had family h story of breast cancer. thirty-two percent of the participating women never practiced bse and % had not undergone cbe during the past two years. the data indicated that % of the women did not have mammography in the last two years. logistic regression analysis showed that age ( r= . , % confi· dcnc~ interval (cl)=l. - . ), having clinical breast examination ( r= . , % cl= . - . ), and practtce of self-breast examination ( r= . , % cl= . - . ), were strong predictors of mammography use . . conclusions: the data point to the need for intervention targeting muslim women to inform and motivate th.cm a~ut practices for early detection of breast cancer and screening. further studies are needed to investigate the factors associated with low utilization of mammography among muslim women population in california. we conducted a review of the scientific literature and° government documents to describe ditnational health care program "barrio adentro" (inside the neighborhood). we also conducted qualiurivt interviews with members of the local health committees in urban settings to descrihe the comm unity participation component of the program. rtsmlts: until recently, the venezuelan public health system was characterized by a lack or limited access w health care ( % of the population) and long waiting lists that amounted to denial of service. moit than half of the mds worked in the five wealthiest metropolitan areas of the country. jn the spring oi , a pilot program hired cuban mds to live in the slums of caracas to provide health care to piople who had previously been marginalized from social programs. the program underwent a massive expansion and in only two years , cuban and , venezuelan health care providers were working acmss the country. they provide a daily average of - medical consultations and home visits, c lly out neighborhood rounds, and deliver health prevention initiatives, including immunization programs. they also provide generic medicines at no cost to patients, which treat % of presenting ill-ij!m, barrio adentro aims to build , clinics (primary care), , diagnostic and rehabilitation ctnrres (secondary care), and upgrade the current hospital infrastructure (tertiary care). local health committees survey the community to identify needs and organize a variety of lobby groups to improve dit material conditions of the community. last year, barrio adentro conducted . times the medical visits conducted by the ministry of health. the philosophy of care follows an integrated approach where btalrh is related to housing, education, employment, sports, environment, and food security. conclusions: barrio adentro is a unique collaboration between low-middle income countries to provide health care to people who have been traditionally excluded from social programs. this program shows that it is possible to develop an effective international collaboration based on participatory democracy. low-income americans are at the greatest risk of being uninsured and often face multiple health concerns. this evaluation of the neighborhood health initiative (nh!), an organization which uses multiple programmatic approaches to meet the multiple health needs of clients, reflected the program's many activities and the clients' many service needs. nh! serves low-income, underserved, and hard-to-reach residents in the des moines enterprise community. multiple approaches (fourth-generation evaluation, grounded theory, strengths-and needs-based) and methods (staff and client interviews, concept mapping, observations, qualitative and quantitative analysis) were used to achieve that reflection. results indicate good targeting of residents in the zip code and positive findings in the way of health insurance coverage and reported unmet health needs of clients. program activities were found to match client nttds, validating the organization\'s assessment of clients. important components of nhi were the staff composition and that the organization had become part of both the formal and informal networks. nhi positioned as a link between the target population and local health and social sc:rvice agencies, working to connect residents with services and information as well as aid local agencies in reaching this underserved population. p - (c) welfare: definition by new york city maribeth gregory for an individual who resides in new york city, to obtain health insurance under the medicaid policy one must fall under certain criteria .. (new york city's welfare programs ) if the individual _is on ssi or earns equal to or less than $ per month, he is entitled to receive no more than $ , m resources. a family the size of two would need to earn less than $ per month to qualify for no greater than ss, worth of medicaid benefits. a family of three would qualify for $ , is they earned less than $ per month and so on. introduction: the vancouver gay communiry has a significant number of asian descendan!l. because of their double minority status of being gay and asian, many asian men who have sex with men (msm) are struggling with unique issues. dealing with racism in both mainstream society and the gay communiry, cultural differences, traditional family relations, and language challenges can be some of their everyday srruggles. however, culturally, sexually, and linguistically specific services for asian msm are very limited. a lack of availability and accessibiliry of culturally appropriate sexual health services isolates asian msm from mainstream society, the gay community, and their own cultural communities, deprives them of self-esteem, and endangers their sexual well-being. this research focuses on the qualita· tive narrative voices of asian msm who express their issues related to their sexualiry and the challenges of asking for help. by listening to their voices, practitioners can get ideas of what we are missing and how we need to intervene in order to reach asian msm and ensure their sexual health. methods: since many asian msm are very discreet, it is crucial to build up trust relationships between the researcher and asian msm in order to collect qualitative data. for this reason, a community based participatory research model was adopted by forming a six week discussion group for asian msm. in each group session, the researcher tape recorded the discussion, observed interactions among the participants, and analyzed the data by focusing on participants' personal thoughts, experiences, and emotions for given discussion topics. ra lts: many asian msm share challenges such as coping with a language barrier, cultural differ· ences for interpreting issues and problems, and westerncentrism when they approach existing sexual health services. moreover, because of their fear of being disclosed in their small ethnic communities, a lot of asian msm feel insecure about seeking sexual health services when their issues are related to their sexual orientation. conclflsion: sexual health services should contain multilingual and multicultural capacities to meet minority clients' needs. for asian msm, outreach may be a more effective way to provide them with accessible sexual health services since many asian msm are closeted and are therefore reluctant to approach the services. building a communiry for asian msm is also a significant step toward including them in healthcare services. a communiry-based panicipatory approach can help to build a community for asian msm since it creates a rrust relationship between a worker and clients. p - (c) identifying key techniques to sustain interpretation services for assisting newcomers isolated by linguistic and cultural barriers from accessing health services s. gopi krishna lntrodaetion: the greater toronto area (gta) is home to many newcomer immigrants and other vulnerable groups who can't access health resources due to linguistic, cultural and systemic barriers. linguistic and cultural issues are of special concern to suburbs like scarborough, which is home to thousands of newcomer immigrants and refugees lacking fluency in english. multilingual community ~nterpreter. service~ (mcis) is a non-profit social service organization mandated to provide high quality mterpretanon services. to help newcomers access health services, mcis partnered with the scarborough network of immigrant serving organizations (sniso) to recruit and train volunteer interpreters to accompany clienrs lacking fluency in english and interpret for them to access health services at various locati?ns, incl~~ing communiry ~c:-lth centres/social service agencies and hospitals. the model envisioned agencies recruin~ and mcis ~.mm.g and creating an online database of pooled interpreter resources. this da.tabase, acces& bl~ to all pama~~g ?rganization is to be maintained through administrative/member · ship fees to. be ~ d by each parnapanng organization. this paper analyzes the results of the project, defines and identifies suc:cases before providing a detailed analysis for the reasons for the success . . methods:. this ~per~ q~ntitative (i.e. client numben) and qualitative analysis (i.e. results of key •~ormant m~rv ews with semce ~sers and interpreters) to analyze the project development, training and mplementanon phases of the project. it then identifies the successes and failures through the afore· mentioned analysis. poster sessions vss resljts: the results of the analysis can be summarized as: • the program saw modest success both ia l?lllls of numbers of clients served as well as sustainability at various locations, except in the hospital iririog. o the success of the program rests strongly on the commitment of not just the volunteer interprmr, but on service users acknowledgments through providing transponation allowance, small honororia, letter of reference etc. • the hospital sustained the program better at the hospital due to the iolume and nature of the need, as well as innate capacity for managing and acknowledging volunceers. collc/llsion: it is possible to facilitate and sustain vulnerable newcomer immigrants access to health !ul'ices through the training and commitment of an interpreter volunteer core. acknowledging volunteer commitment is key to the sustenance of the project. this finding is important to immigration and health policy given the significant numbers of newcomer immigrants arriving in canada's urban communities. nity program was established in to provide support to people dying at home, especially those who were waiting for admission to the resi<lential hospice. with the advent of haart and corresponding challenges for people living with hiv/aids in the community, the community program has developed a unique case management approach. this model features an interdisciplinary team providing a clientdrivcn service. the case manager provides continuity of care to clients in a variety of settings both within and outside of the health care system. a case study is used to demonstrate how formal and informal networks of support facilitate efficient and appropriate resource utilization to promote client health. this case study demonstrates the value of consistent coordination with a client who has complex physical, spiritual, substance use and mental health needs. the authors will show how they liaised with the housing authority, police, social services as well as the family physician, clinic staff and a hospital emergtncy room to ensure this client did not fall between the cracks. tarek hussain recognition of the importance of community involvement and sectoral cooperation in health and !ocial services, formalized in alma-ata declaration in , was reinforced at riga meeting held at the mid·point between alma-ata and the year . then at the th anniversary of alma-ata declaration, ir was declared that 'primary health care is everybody's business'. health does not exist in isolation. health cannot be defined only as an outcome of 'medical care' but also as one of 'social action'; the responsibility of disease prevention and health promotion rests not only on governments, but also with don·govemmentorgan izations, the community, and individuals. the major accomplishment to date may be that rhere is growing realization in the health sector that community involvement is more than a political right-it is absolute necessary. lessons have learned during the implementation of disease-specific l'cltical programmes, such as cdd, ari, and epi; first, integrated and holistic approaches to childcare art needed, and second, the need for community involvement has become evident. imc! is a broad inte-gra ed strategy with an overall objective contributing to reducing child morbidity and mortality in developing countries. and one of the imci components, 'community !mci', which is now broadening ~s an entry point for child-focused community development initiatives. community jmcl/c~ ld health is ~n mtcgrated approach to the promotion of key family and community practices that have impact on: child growth and development, disease prevention, home care for sick, malnourished child~en, a.nd care-seekmg behavior and compliance with advice and treatment. the presentation addres~es, m brief, the ~evel opinent of community !mci, operational aspect of community/im cl, key strategies and tools ava la~le for implementation of c/imci. the paper draws some successful programme examples on working logether for imc! with the community in various countries which had substantial benefns on programme outcomes. p - t (c) healthy child screening: an innovative service initiative ann-marie marcolin and joyce allen . introduction: with mounting attention for creative and integrated models of c~re .that are populallon and community focused, the healthy child screening initiative achiev.es t~ese pnncipl~s and more! . • parkdale high park rotary (sponsorship) the heal~h ~h ld scree? ?g is a ~opl~-centred model of care. agency and professional sector-specific silos are ehmmated, ~rov dmg f~~ hes wit~ one-sto~ access to primary prevention services in a local school gym! children at nsk are rece vmg early mtervent n and appropriate referrals to the right care provider, at the right time a~d in t~e right place. further, with a complimentary focus on prevention, the program serves to keep at nsk children healthy. healthy child screening results: the service model is developed around four distinct phases: ) planned outreach; ) coordinated intake and registration; ) interdisciplinary screening; and ) targeted referral. since the fall and through six collaborative healthy child screenings children ranging in age from to have benefited from this unique service model of care. conclusion: the presentation will provide practical information on the development and implementation of the model. there will also be a focus on lessons learned in building community service provider-hospital relationships. according to statistics canada ( ) % of the toronto population was born outside of canada and % were new immigrants. immigrants often arrive in canada in superior health compared to the canadian born population, but they lose this health advantage over time. changes in immigrant health status over time may be attributed to a variety of factors including barriers to accessing and receiving care as well as limitations in the mainstream health service organizations and their approaches to health care delivery (hyman, ) . for example, immigrant women are less likely to receive pap tests, which places them at a greater risk for developing cervical cancer. similarly, immigrant women receive less mammography screening than their canadian counterparts. the immigrant women's health centre mobile health unit (mhu) was created as an alternative care delivery model to address the need for increased accessibility as well as culturally and linguistically appropriate reproductive health care. toronto western hospital and the immigrant women's health centre have formed a collaborative partnership which incorporates a primary care nurse practitioner and lay ethnocultural counselors providing care on the mhu. currently, a qualitative ethnonursing study is underway to understand the unique experiences of women using the mhu for their reproductive health care as well as the perspectives of the mhu health care providers. based on a literature review and preliminary findings from provider and participant interviews, the proposed presentation will address the themes of health status for immigrant and refugee women, accessibility issues as well strategies to improve their reproductive health care. we will discuss benefits as well as limitations to health care provision using this alternative service delivery model. michael carden, brian edlin, andrew talal, elizabeth getter, and marla shu lntrod.ction: to date most active drug users have not had access to treatment for hepatitis c virus (hcv) infection and substantial barriers continue to exist that interfere with treatment availability for this population. methods: active illicit drug users interested in pursuing hcv care and treatment were recruited in partnership w~th co~munity-based organizations (cbo's) in new york city. baseline data were collected on quahty of hfe, substance use patterns, depression, health care utilization, hcv health beliefs and other relev.ant variables. medical evaluations were conducted, including liver biopsy when indicated, an~ treatment ts ~ffered when no contraindications are present. participants also receive psychiatric evaluahons to determme the appropriateness of interferon treatment. renlts: fifteen individuals have been recruited to date and received an initial medical evaluation. the mean age was years and _the average age of initial heroin or cocaine use was . . eight ( %) ha~ been homeless at least once m the last months and s ( %) were homeless for most or all of this penod. fourteen ( %) had a history of injection drug use with the mean age at first injection being s frsewons v ,an. elrven persc.!ns ( %) reported inje~~ng .heroin or cocaine within the last days while the .wing four ( l'o) reported regular non-m ect on use of cocaine and street-obtained benzodiazepines. sijiy seven percent of the sample (n= ) reported ever being referred to hcv treatment while ( t % ) ftponeddiattreann~nt had been offered by~ ~e.dical provider. none had ever received a liver biopsy or araanent. most believed that hcv was a s gmf cant threat to their health ( %) and that there was a pm)dchance they would eventually die if their hepatitis c was not treated ( %). though individuals % believed that there was no cure for hcv, ( %) reported that they would initiate treatment if i was recommended by their doctor. thirteen ( %) had a current psychiatric diagnosis including «pmsion, anxiety disorder, schizophrenia, schizoaffective disorder, and borderline and antisocial persooaliry disorders. among eight individuals who had the beck depression inventory administered, the mean score was . . attendance rates were % ( / ) at scheduled medical and psychiatric ppointments and % ( / ) at liver biopsy. <andtuions: active drug users, despite experiencing multiple psycho-social problems, can be mgaged in hcv care using a multidisciplinary approach, but require intensive follow-up support. hcv aunnent of active drug users should not be dismissed. n- (c) antiretroviral therapy in mv infected infants: when to initiate therapy an african experience kingsley okonkwo, ademola adeyemo, israel sokeye, and nwaife umeike /""°""ction: as technology for early diagnosis of human immunodeficiency virus [hiv] improves, m to commence highly active antiretroviral therapy [haarn is yet to be fully evaluated. this prospective study describes our initial experience with early haart in hiv infected nigerian infants and rqions the outcome. we also analyzed the socioeconomic implications of early haart therapy in infants in the african setting. method: hiv infected infants were started on haart before months and followed up at mkly intervals.we monitored baseline and monthly cd . conclusion: initial results suggest early haart before months resulted. in improv~d out~ome in african children. treatment appears to be as effective as in developed counmes. in. a~nca as. m most developing countries with limited resources it is possible and effective to use haart m ~~ants if p~oper llloniroring facilities are available. however the occurrence of long-term drug related tox c ty and mk of emergence of resistant viral strains create need for further evaluation of haart in infants. background: most risk factors for cardiovascular disease (cvd) can be mitigated through ~th clinical interventions and lifestyle change. we used data from a telephone survey of new york city (nyc) adults to characterize health care access and healthy behavior among those with three or more cvd risk factors. methods: the study population included respondents to the nyc community health survey (n= , ) self-reporting~ of the following: smoking, diabetes, high cholesterol level, high blood pres· sure, body mass index > , and age > (males) or > (females) (n= , ). results: based on self-report, an estimated . , ( %) of nyc adults have~ or more cvd risk factors. this population is % male, % white, % black, and % with s years of education. most report good access to health care, indicated by having health insurance ( %), regular doctor ( %), their blood pressure checked within last months ( %), and their choles· terol checked within the past year ( % ). only % reported getting at least minutes of exercise ~ times per week and only % eating ~ servings of fruits and vegetables the previous day. among current smokers, % attempted to quit in past months, but only % used medication or counseling. implications: these data suggest that most nyc adults known to be at high risk for cvd have access to regular health care, but most do not engage in healthy lifestyle or, if they smoke, attempt effective quit strategies. more clinic-based and population-level interventions are needed to support lifestyle change among those at high risk of cvd. introduction: recently, much interest has been directed at "obesogenic" (obesity-promoting) (swinburn, egger & raza, ) built environments, and at geographic information systems (gis) as a tool for their exploration. a major geographical concept is accessibility, or the ease of moving from an origin to a destination point, which has been recently explored in several health promotion-related stud· ies. there are several methods of calculating accessibility to an urban feature, each with its own strengths, drawbacks and level of precision that can be applied to various health promotion research issues. the purpose of this paper is to describe, compare and contrast four common methods of calculating accessibility to urban amenities in terms of their utility to obesity-related health promotion research. practical and conceptual issues surrounding these methods are introduced and discussed with the intent of providing health promotion researchers with information useful for selecting the most appropria e accessibility method for their research goal~ ~ethod: this paper describes methodological insights from two studies, both of which assessed the neighbourhood-level accessibility of fast-food establishments in edmonton, canada -one which used a relatively simple coverage method and one which used a more complex minimum cos method. res.its: both methods of calculating accessibility revealed similar patterns of high and low access to fast-food outlets. however, a major drawback of both methods is that they assume the characteristics of the a~e~ities and of the populations using them are all the same, and are static. the gravity potential method is introduced as an alternative, since it is ·capable of factoring in measures of quality and choice. a n~mber of conceptual and pr~ctical iss~es, illustrated by the example of situational influences on food choice, make the use of the gravity potential model unwieldy for health promotion research into sociallydetermined conditions such as obesity. co.nclusions: i~ ~ommended that geographical approaches be used in partnership with, or as a foun~ation for, ~admonal exploratory methodologies such as group interviews or other forms of commumty consultation that are more inclusive and representative of the populations of interest. qilhl in los angeles county ,,..ia shaheen, richard casey, fernando cardenas, holman arthurs, and richard baker ~the retinomax autorefractor has been used for vision screening of preschool age childien. ir bas been suggested to be used and test school age children but not been validated in this age poup. ob;taiw: to compare the results of retinomax autorefractor with findings from a comprehensive i!' examination using wet retinoscopy for refractive error. mllhods: children - years old recruited from elementary schools at los angeles county were iaml with snellen's chart and the retinomax autorefractor and bad comprehensive eye examination with dilation. the proportion of children with abnormal eye examination as well as diesensitiviry and specificity of the screening tools using retinomax autorefractor alone and in combinalion wirh snellen's chart. results of the children enrolled in the study (average age= . ± . years; age range, - years), ?% had abnormal eye examination using retinoscopy with dilation. for the lerinomax, the sensitivity was % ( % confidence interval [ci] %- %), and the specificity was % ( % ci, %- o/o). simultaneous testing using snellen's chart and retinomax resulted in gain in sitiviry ( %, % cl= , ), and loss in specificity ( %, % cl= %- %). the study showed that screening school age children with retinomax autorefractor could identify most cases with abnormal vision but would be associated with many false-positive results. simuhaneous resting using snellen's chart and retinomax maximize the case finding but with very low specificiry. mdhotjs: a language-stratified, random sample of members of the college of family physicians of canada received a confidential survey. the questionnaire collected data on socio-demographic characteristics, medical training, practice type, setting and hcv-related care practices. the self-adminisratd questionnaire was also made available to participants for completion on the internet. batdti: response proportion was %. median age was years ( % female) and the proporlionoffrench questionnaires was %. approximately % had completed family medicine residency lllining in canada; median year of training completion was . sixty-seven percent, % and % work in private offices/clinics, community hospitals and emergency departments, respectively. regarding ~practices, % had ever requested a hcv test and % of physicians had screened for hcv iafrction in rhe past months· median number of tests was . while % reported having no hcv-uaed patients in their practic~, % had - hcv-infected patients. regarding the level of hcv care provided, . % provide ongoing advanced hcv care including treatment and dose monitoring for ctmduions: in this sample of canadian family physicians, most had pro~ided hcv screening. to •least one patient in the past year. less than half had - hcv-infected patients and % provide ~:relared care the role of socio-demographic factors, medical training as wel_i as hcv ca~e percep-lldas rhe provision of appropriate hcv screening will be examined and described at the time of the canference. ' - (c) healthcare services: the context of nepal meen poudyal chhetri """ tl.ction healthcare service is related with the human rights and fundamental righ~ of the ci~ ciaaiuntry. however, the growing demand foi health care services, quality heal~care service, accessib b~ id die mass population and paucity of funds are the different but interrelated issues to .be ~ddressed. m nepat. n view of this context, public health sector in nepal is among other sectors, which is struggling -.i for scarce resources. . . . nepal, the problems in the field of healthcare servic~s do not bnut ~o the. paucity of faads and resources only, but there are other problems like: rural -urban imbalance, regional unbalance, poster sessio~ f the ll ·m ·ted resources poor healthcare services, inequity and inaccessibility of the poor management o , . poor people of the rural, remote and hilly areas for the healthcare services and so on.. . . . · . i f ct the best resource allocation is the one that max m zes t e sum o m ivi ua s u · ea t services. n a , · h d' ·b · · · h . ·t effi.ciency and efficient management are correlated. it might be t e re istn utmn of mes. ence, equi y, . . . . . income or redistribution of services. moreover, maximizanon of available resources, qua tty healthcare services and efficient management of them are the very important and necessary tools and techmques to meet the growing demand and quality healthcare services in nepal. p - (a) an jn-depth analysis of medical detox clients to assist in evidence based decision making xin li, huiying sun, ajay puri, david marsh, and aslam anis introduction: problematic substance use represents an ever-increasing public health challenge. in the vancouver coastal health (vch) region, there are more than , individuals having some probability of drug or alcohol dependence. to accommodate this potential demand for addiction related services, vch provides various services and treatment, including four levels of withdrawal management services (wms). clients seeking wms are screened and referred to appropriate services through a central telephone intake service (access i). the present study seeks to rigorously evaluate one of the services, vancouver detox, a medically monitored -bed residential detox facility, and its clients. doing so will allow decision makers to utilize evidence based decision-making in order to improve the accessibility and efficiency of wms, and therefore, the health of these clients. methods: we extract one-year data (october , -september , from an efficient and comprehensive database. the occupancy rate of the detox centre along with the clients' wait time for service and length of stay (los) are calculated. in addition, the effect of seasonality on these variables and the impact of the once per month welfare check issuance on the occupancy rate are also evaluated. results: among the clients (median age , % male) who were referred by access! to vancouver detox over the one-year period, were admitted. the majority ( %) of those who are not admitted are either lost to follow up (i.e., clients not having a fixed address or telephone) or declined service at time of callback. the median wait time was day [q -ql: - ], the median los was days iq -qt: - ], and the average bed occupancy rate was %. however, during the threeday welfare check issue period the occupancy rate was lower compared to the other days of the year % vs. %, p conclusion: our analysis indicates that there was a relatively short wait time at vancouver detox, however % of the potential clients were not served. in addition, the occupancy rate declined during the welfare check issuance period and during the summer. this suggests that accessibility and efficiency at vancouver detox could be improved by specifically addressing these factors. background: intimate partner violence (ipv) is associated with acute and chronic physical and men· tal health outcomes for women resulting in greater use of health services. yet, a vast literature attests to cultural variations in perceptions of health and help-seeking behaviour. fewer studies have examined differences in perceptions of ipv among women from ethnocultural communities. the recognition, definition, and understanding of ipv, as well as the language used to describe these experiences, may be different in these communities. as such, a woman's response, including whether or not to disclose or seek help, may vary according to her understanding of the problem. methods: this pilot study explores the influence of cultural factors on perceptions of and responses to ipv among canadian born and immigrant young women. in-depth focus group interviews were con· ducted with women, aged to years, living in toronto. open-ended and semi-structured interview questions were designed to elicit information regarding how young women socially construct jpv and where they would go to receive help. interviews were transcribed, then read and independently coded by the research team. codes were compared and disagreements resolved. qualitative software qsr n was used to assist with data management. . ruu~ts_: res~nses_abo~t what constitutes ipv were similar across the study groups. when considering specific ab.us ve ~ tuanons and types of relationships, participants held fairly relativistic views about ipv, especially with regard to help-seeking behaviour. cultural differences in beliefs about normaive m;ile/femal~ relations. familial.roles, and customs governing acceptable behaviours influenced partictpants perceptions about what n ght be helpful to abused women. interview data highlight the social l ter srnfons v suucrural _impact these factors ha:e on you?g women and provide details regarding the dynamics of cibnocultur~ m~uences on help-~eekmg behav ur: t~e ro~e of such factors such as gender inequality within rtlaoo?sh ps and t_he ~erce ved degree of ~oc al solat on and support nerworks are highlighted. collc~ the~ findmgs unde~score the _ mporta_nc_e of understanding cultural variations in percrprions of ipv ~ relanon to ~elp-seekmg beha~ ':'ur. th s_mformation is critical for health professionals iodiey may connnue developmg culturally sensmve practices, including screening guidelines and protorol s. ln addition, _this study demonstr~tes that focus group interviews are valuable for engaging young romen in discussions about ipv, helpmg them to 'name' their experiences, and consider sources of help when warranted. p -s (a) health problems and health care use of young drug users in amsterdam .wieke krol, evelien van geffen, angela buchholz, esther welp, erik van ameijden, and maria prins / trod ction: recent advances in health care and drug treatment have improved the health of populations with special social and health care needs, such as drug users. however, still a substantial number dots not have access to the type of services required to improve their health status. in the netherlands, tspccially young adult drug users (yad) whose primary drug is cocaine might have limited access to drugrreatment services. in this study we examined the history and current use of (drug associated) treatmmt services, the determinants for loss of contact, and the current health care needs in the young drug mm amsterdam study (yodam). methods: yodam started in and is embedded in the amsterdam cohort study among drug mm. data were derived from y ad aged < years who had used cocaine, heroin, ampheramines and i or methadone at least days a week during the months prior to enrolment. res lts:of yao, median age was years (range: - years), % was male and % had dutch nationality at enrolment. nearly all participants ( %) reported a history of contact with drug llt.lnnent services (methadone maintenance, rehabilitation clinics and judicial treatment), mental health car? (ambulant mental care and psychiatric hospital) or general treatment services (day-care, night-care, hdp for living arrangements, work and finance). however, only % reported contact in the past six l!xlllths. this figure was similar in the first and second follow-up visit. among y ad who reported no current contact with the health care system, % would like to have contact with general treatment serl' icts. among participants who have never had contact with drug treatment services, % used primarily cocaine compared with % and % among those who reported past or current contact, respectively. saied on the addiction severity index, % reported at least one mental health problem in the past days, but only % had current contact with mental health services. concl sion: results from this study among young adult drug users show that despite a high contact rm with health care providers, the health care system seems to lose contact with yao. since % indicatt the need of general treatment services, especially for arranging house and living conditions, health m services that effectively integrate general health care with drug treatment services and mental health care might be more successful to keep contact with young cocaine users. mtthods: respondents included adults aged and over who met dsm-iv diagn?snc criteria for an anxiety or depressive disorder in the past months. we performed two sets of logisnc regressmns. thtdichotomous dependent variables for each of the regressions indicated whether rhe respondenr_vis-ud a psychiatrist, psychologist, family physician or social worker in the _past_ months. no relationship for income. there was no significant interaction between educatmn an mco~:· r: ::or respondents with at least a high school education to seek help ~rom any of the four servic p were almost twice that for respondents who had not completed high school. th . d ec of analyses found che associacion becween educacion and use of md-provided care e secon s · · be d · · ·f· ly ·n che low income group for non-md care, the assoc anon cween e ucatlon and was s gm icant on -· . . . . use of social workers was significant in both income groups, but significant only for use of psychologists in che high-income group. . . . conclusion: we found differences in healch service use by education level. ind v duals who have nor compleced high school appeared co use less mental he~lt~ servi~es provided ~y psyc~iatrists, psycholo· gists, family physicians and social workers. we found limited e.v dence _suggesting the influence of educa· tion on service use varies according to income and type of service provider. results suggesc there may be a need to develop and evaluate progr~ms.designe~ to deliver targeted services to consumers who have noc completed high school. further quahtanve studies about the expen· ence of individuals with low education are needed to clarify whether education's relationship with ser· vice use is provider or consumer driven, and to disentangle the interrelated influences of income and education. system for homeless, hiv-infected patients in nyc? nancy sahler, chinazo cunningham, and kathryn anastos introduction: racial/ethnic disparities in access to health care have been consistently documented. one potential reason for disparities is that the cultural distance between minority patients and their providers discourage chese patients from seeking and continuing care. many institucions have incorporated cultural compecency craining and culturally sensicive models of health care delivery, hoping co encourage better relacionships becween patients and providers, more posicive views about the health care system, and, ulcimacely, improved health outcomes for minority patients. the current scudy tests whether cultural distance between physicians and patients, measured by racial discordance, predicts poorer patient attitudes about their providers and the health care system in a severely disadvantaged hiv-infected population in new york city that typically reports inconsistent patterns of health care. methods: we collected data from unscably housed black and latino/a people with hiv who reported having a regular health care provider. we asked them to report on their attitudes about their provider and the health care system using validated instruments. subjects were categorized as being racially "concordant" or "discordant" with their providers, and attitudes of these two groups were compared. results: the sample consisted of ( %) black and ( %) latino/a people, who reported having ( %) black physicians, ( %) latino/a physicians, ( %) white physicians, and ( %) physicians of another/unknown race/ethnicity. overall, ( %) subjects had physicians of a different race/ethnicity than their own. racial discordance did not predict negative attitudes about rela· tionship with providers: the mean rating of a i-item trust in provider scale (lo=high and o=low) was . for both concordant and discordant groups, and the mean score in -icem relationship with provider scale ( =high and !=low) was . for both groups. however discordance was significantly associated with distrust in che health care syscem: che mean score on a -icem scale ( =high discrust and l=low distrust) was . for discordant group and . for che concordant group (t= . , p= . ). we further explored these patterns separacely in black and lacino/a subgroups, and using different strategies ro conceptualize racial/ethic discordance. conclusions: in this sample of unscably housed black and latino/a people who receive hiv care in new york city, having a physician from the same racial/ethnic background may be less important for developing a positive doctor-patient relationship than for helping the patients to dispel fear and distrust about the health care system as a whole. we discuss the policy implications of these findings. ilene hyman and samuel noh . .abstract objectiw: this study examines patterns of mental healthcare utilization among ethiopian mm grants living in toronto. methods: a probability sample of ethiopian adults ( years and older) completed structured face-to-face interviews. variables ... define, especially who are non-health care providers. plan of analysis. results: approximately % of respondents received memal health services from mainstream healthcare providers and % consulted non-healthcare professionals. of those who sought mental health services from mainstream healthcare providers, . % saw family physicians, . % visited a psychiatrist. and . % consulted other healthcare providers. compared with males, a significantly higher proportion gsfer sessions v ri ftlnales consulted non-healthcare_ professionals for emotional or mental health problems (p< . ). tlbile ethiopian's overall use of mamstream healthcare services for emotional problems ( %) did not prlydiffer from the rate ( %) of the general population of ontario, only a small proportion ( . %) rjerhiopians with mental health needs used services from mainstream healthcare providers. of these, !oj% received family physicians' services, . % visited a psychiatrist, and . % consulted other healthll/c providers. our data also suggested that ethiopian immigrants were more likely to consult tradioooal healers than health professionals for emotional or mental health problems ( . % vs. . % ). our bivariate analyses found the number of somatic symptoms and stressful life events to be associated with an increased use of medical services and the presence of a mental disorder to be associated with a dfcreased use of medical services for emotional problems. however, using multivariate methods, only die number of somatic symptoms remained significantly associated with use of medical services for emooonal problems. diu#ssion: study findings suggest that there is a need for ethnic-specific and culturally-appropriate mrcrvention programs to help ethiopian immigrants and refugees with mental health needs. since there ~a strong association between somatic symptoms and the use family physicians' services, there appears robe a critical role for community-based family physicians to detect potential mental health problems among their ethiopian patients, and to provide appropriate treatment and/or referral. the authors acknowledge the centre of excellence for research in immigration and settlement (ceris) in toronto and canadian heritage who provided funding for the study. we also acknowledge linn clark whose editorial work has improved significantly the quality of this manuscript. we want to thank all the participants of the study, and the ethiopian community leaders without whose honest contributions the present study would have not been possible. this paper addresses the impact of the rationalization of health-care services on the clinical decision-making of emergency physicians in two urban hospital emergency departments in atlantic canada. using the combined strategies of observational analysis and in-depth interviewing, this study provides a qualitative understanding of how physicians and, by extension, patients are impacred by the increasing ancmpts to make health-care both more efficient and cost-effective. such attempts have resulted in significantly compromised access to primary care within the community. as a consequence, patients are, out of necessity, inappropriately relying upon emergency departments for primary care services as well as access to specialty services. within the hospital, rationalization has resulted in bed closures and severely rmricted access to in-patient services. emergency physicians and their patients are in a tenuous position having many needs but few resources. furthermore, in response to demands for greater accountability, physicians have also adopted rationality in the form of evidence-based medicine. ultimately, ho~ever, rationality whether imposed upon, or adopted by, the profession significantly undermines physu.: ans' ability to make decisions in the best interests of their patients. johnjasek, gretchen van wye, and bonnie kerker introduction: hispanics comprise an increasing proportion of th.e new york city (nyc) populanon !currently about %). like males in the general population, h spamc males (hm) have a lower prrval,nce of healthcare utilization than females. however, they face additional access barriers such as bnguage differences and high rates of uninsurance. they also bear a heavy burden of health problems lllehasobesity and hiv/aids. this paper examines patterns of healthcare access and ut hzat on by hm compared to other nyc adults and identifies key areas for intervention. . . . and older are significantly lower than the nhm popu anon . v. . , p<. ), though hi\' screening and immunizations are comparable between the two groups. conclusion: findings suggest that hm have less access t? healthcare than hf or nhm. hown r, hm ble to obtain certain discrete medical services as easily as other groups, perhapsdueto!rtor are a hm. i i . subsidized programs. for other services, utilization among s ower. mprovmg acc~tocareinthis group will help ensure routine, quality care, which can lead to a greater use of prevennve services iii! thus bener health outcomes. introduction: cancer registry is considered as one of the most important issues in cancer epidemiology and prevention. bias or under-reporting of cancer cases can affect the accuracy of the results of epidemiological studies and control programs. the aim of this study was to assess the reliability of the regional cancer report in a relatively small province (yasuj) with almost all facilities needed for c llcll diagnosis and treatment. methods: finding the total number of cancer cases we reviewed records of all patients diagnoicd with cancer (icd - ) and registered in any hospital or pathology centre from until i n yasuj and all ( ) surrounding provinces. results: of patients who were originally residents of yasui province, . % wereaccoulll!d for yasuj province. the proportion varies according to the type of cancer, for exarnplecancetsofdiglstive system, skin and breast were more frequently reported by yasuj's health facilities whereas cancmoi blood, brain and bone were mostly reported by neighbouring provinces. the remaining cases ( . % were diagnosed, treated and recorded by neighbouring provinces as their incident cases. this is partly because of the fact that patients seek medical services from other provinces as they believed that the facil. ities are offered by more experienced and higher quality stuffs and their relative's or temporary acooiii' modation addresses were reported as their place of residence. conclusion: measuring the spatial incidence of cancer according to the location of report ortht current address affected the spatial statistics of cancer. to correct this problem recording the permanm! address of diagnosed cases is important. p - (c). providing primary healthcare to a disadvantaged population at a university-run commumty healthcare facility tracey rickards the. c:ommuni~y .h~alth ~linic (chc) is a university sponsored nurse-managed primary bealthwt (p~c:l clime. the clm c is an innovative model of healthcare delivery in canada that has integrated tht principles of phc ser · · h' . vices wit ma community development framework. it serves to provide access to phc services for members of th · · illi · dru is ii be . . e community, particularly the poor and those who use or gs, we mg a service-learning facil'ty f d · · · · · · d rionll h . . .,m.:. · t · . meet c ient nee s. chmc nursing and social work staff and srudents r·--· ipa em various phc activities and h .l.hont" less i . f . outreac services in the local shelters and on the streels to'"" popu auon o fredericton as well th chc · model iii fosterin an on oi : . • e promotes and supports a harm reduction . · local d!or an~ h ng ~art:ersh p with aids new brunswick and their needle exchange program, w tha ing condoms and :xu:t h:~~~e e~aint~nance therapy clients, and with the clie~ts themselves ~_r; benefits of receiving health f ucation, a place to shower, and a small clothing and food oai~· care rom a nurse p · · d d · --""~'i"· are evidenced in th r research that involved needsaans mvo ves clients, staff, and students. to date the chc has unacn- · sessment/enviro i . d ; •• '"""" ll eva uanon. the clinic has also e . d nmenta scan, cost-benefit analysis, an on-go...,, "".'i'~ facility and compassionate lea x~mme the model of care delivery' focusing on nursing roles wi~ cj rmng among students. finally, the clinic strives to share the resu•p v . -arch with the community in which it provides service by distributing a bi-monthly newsletter, and plllicipating in in-services and educational sessions in a variety of situations. the plan for the future is coolinued research and the use of evidence-based practice in order to guide the staff in choosing how much n~ primary healthcare services to marginalized populations will be provided. n- (c) tuming up the volume: marginalized women's health concerns tckla hendrickson and betty jane richmond bdrotbu:tion: the marginalization of urban women due to socio-economic status and other determinants negatively affects their health and that of their families. this undermines the overall vitaliry of urban communities. for example, regarding access to primary health care, women of lower economic surus and education levels are less likely to be screened for breast and cervical cancer. what is not as widely reported is how marginalized urban women in ontario understand and articulate their lack of access to health care, how they attribute this, and the solutions that they offer. this paper reports on the rnults of the ontario women's health network (owhn) focus group project highlighting urban women's concerns and suggestions regarding access to health care. it also raises larger issues about urban health, dual-purpose focus group design, community-based research and health planning processes. mdhods: focus group methodology was used to facilitate a total of discussions with urban and rural women across ontario from to . the women were invited to participate by local women's and health agencies and represented a range of ages, incomes, and access issues. discussions focussed on women's current health concerns, access to health care, and information needs. results were analyzed using grounded theory. the focus groups departed from traditional focus group research goals and had two purposes: ) data collection and dissemination (representation of women's voices), and ) fostering closer social ties between women, local agencies, and owhn. the paper provides a discussion and rationale for a dual approach. rax/ts: the results confirm current research on women's health access in women's own voices: urban women report difficulty finding responsive doctors, accessing helpful information such as visual aids in doctors' offices, and prohibitive prescription costs, in contrast with rural women's key concern of finding a family doctor. the research suggests that women's health focus groups can address access issues by helping women to network and initiate collective solutions. the study shows that marginalized urban women are articulate about their health conctrns and those of their families, often understanding them in larger socio-economic frameworks; howtver, women need greater access to primary care and women-friendly information in more languages and in places that they go for other purposes. it is crucial that urban health planning processes consult directly with women as key health care managers, and turn up the volume on marginalized women's voices. women: an evaluation of awareness, attitudes and beliefs introduction: nigeria has one of the highest rates of human immunodeficiency virus ihivi seroprrvalence in the world. as in most developing countries vertical transmission from mother to child account for most hiv infection in nigerian children. the purpose of this study was ro. determine the awareness, attitudes and beliefs of pregnant nigerian women towards voluntary counseling and testing ivct! for hiv. mnbod: a pre-tested questionnaire was used to survey a cross section '.>f. pregnant women ~t (lrlleral antenatal clinics in awka, nigeria. data was reviewed based on willingness to ~c~ept or re ect vct and the reasons for disapproval. knowledge of hiv infection, routes of hiv transm ssmn and ant rnroviral therapy iart) was evaluated. hsults: % of the women had good knowledge of hiv, i % had fair knowledge while . % had poor knowledge of hiv infection. % of the women were not aware of the association of hreast milk feeding and transmission of hiv to their babies. majority of the women % approved v~t while % disapproved vct, % of those who approved said it was because vct could ~educe risk of rransmission of hiv to their babies. all respondents, % who accepted vc.i ~ere willing to be tnted if results are kept confidential only % accepted to be tested if vc.t results w. be s~ared w .th pinner and relatives % attributed their refusal to the effect it may have on their marriage whale '-gave the social 'and cultural stigmatization associated with hiv infection for their r~fusal.s % wall accept vct if they will be tested at the same time with their partners. ~ of ~omen wall pref~r to breast feed even if they tested positive to hiv. women with a higher education diploma were times v more likely to accept vct. knowledge of art for hiv infected pregnant women as a means of pre. vention of maternal to child transmission [pmtct) was generally poor, % of respondents wm aware of art in pregnancy. conclusion: the acceptance of vct by pregnant women seems to depend on their understanding that vct has proven benefits for their unborn child. socio-cultur al factors such as stigmatizationof hiv positive individuals appears to be the maj_or impedi~ent towards widespread acceptanee of ycr in nigeria. involvemen t of male partners may mpro~e attitudes t~wa~ds vct:the developmentofm novative health education strategies is essential to provide women with mformanon as regards the benefits of vct and other means of pmtct. p - (c) ethnic health care advisors in information centers on health care and welfare in four districts of amsterdam arlette hesselink, karien stronks, and arnoud verhoeff introduction : in amsterdam, migrants report a "worse actual health and a lower use of health care services than the native dutch population. this difference might be partly caused by problems migrants have with the dutch language and health care and welfare system. to support migrants finding their way through this system, in four districts in amsterdam information centers on health care and welfare were developed in which ethnic health care advisors were employed. their main task is to provide infor· mation to individuals or groups in order to bridge the gap between migrants and health care providers. methods: the implementat ion of the centers is evaluated using a process evaluation in order to give inside in the factors hampering and promoting the implementat ion. information is gathered using reports, attending meetings of local steering groups, and by semi-structu red interviews with persons (in)directly involved in the implementat ion of the centers. in addition, all individual and groupcontaets of the health care advisors are registered extensively. results: since four information centers, employing ethnic health care advisors, are implemented. the ethnicity of the health care advisors corresponds to the main migrant groups in the different districts (e.g. moroccan, turkeys, surinamese and african). depending on the local steering groups, the focus of the activities of the health care advisors in the centers varies. in total, around individual and group educational sessions have been registered since the start. most participants were positive about the individual and group sessions. the number of clients and type of questions asked depend highly on the location of the centers (e.g. as part of a welfare centre or as part of a housing corporation). in all districts implementa tion was hampered by lack of ongoing commitment of parties involved (e.g. health care providers, migrant organization s) and lack of integration with existing health care and welfare facilities. discussion: the migrant health advisors seem to have an important role in providing information on health and welfare to migrant clients, and therefore contribute in bridging the gap between migrants and professionals in health care and welfare. however, the lack of integration of the centers with the existing health care and welfare facilities in the different districts hampers further implementation . therefore, in most districts the information centres will be closed down as independent facilicities in the near future, and efforts are made to better connect the position of migrant health advisor in existing facilities. the who report ranks the philippines as ninth among countries with a high tb prevalence. about a fourth of the country's population is infected, with majority of cases coming from the lower socioeconomic segments of the community. metro manila is not only the economic and political capital of the philippines but also the site of major universities and educational institutions. initial interviews with the school's clinicians have established the need to come up with treatment guidelines and protocols for students and personnel when tb is diagnosed. these cases are often identified during annual physical examinations as part of the school's requirements. in many instances, students and personnel diagnosed with tb are referred to private physicians where they are often lost to follow-up and may have failure of treatment due to un monitored self-administered therapy. this practice ignores the school clinic's great potential as a tb treatment partner. through its single practice network (spn) initiative, the philippine tuberculosis initiatives for the private sector (philippine tips), has established a model wherein school clinics serve as satellite treatment partners of larger clinics in the delivery of the directly observed treatment, short course (dots) protocol. this "treatment at the source" allows school-based patients to get their free government-suppl ied tb medicines from the clinic each day. it also cancels out the difficulty in accessing medicines through the old model where the patient has to go to the larger clinic outside his/her school to get treatment. the model also enables the clinic to monitor the treatment progress of the student and assumes more responsibility over their health. this experience illustrates how social justice in health could be achieved from means other than fund generation. the harnessing of existing health service providers in urban communities through standardized models of treatment delivery increases the probability of treatment success, not only for tb but for other conditions as well. p - (c) voices for vulnerable populations: communalities across cbpr using qualitative methods martha ann carey, aja lesh, jo-ellen asbury, and mickey smith introduction: providing an opportunity to include, in all stages of health studies, the perspectives and experiences of vulnerable and marginalized populations is increasingly being recognized as a necessary component in uncovering new solutions to issues in health care. qualitative methods, especially focus groups, have been used to understand the perspectives and needs of community members and clinical staff in the development of program theory, process evaluation and refinement of interventions, and for understanding and interpreting results. however, little guidance is available for the optimal use of such information. methods: this presentation will draw on diverse experiences with children and their families in an asthma program in california, a preschool latino population in southern california, a small city afterschool prevention program for children in ohio, hiv/aids military personnel across all branches of the service in the united states, and methadone clinic clients in the south bronx in new york city. focus groups were used to elicit information from community members who would not usually have input into problem definitions and solutions. using a fairly common approach, thematic analysis as adapted from grounded theory, was used to identify concerns in each study. next we looked across these studies, in a meta-synthesis approach, to examine communalities in what was learned and in how information was used in program development and refinement. results: while the purposes and populations were diverse, and the type of concerns and the reporting of results varied, the conceptual framework that guided the planning and implementation of each study was similar, which led to a similar data analysis approach. we will briefly present the results of each study, and in more depth we will describe the communalities and how they were generated. conclusions: while some useful guidance for planning future studies of community based research was gained by looking across these diverse studies, it would be useful to pursue a broader examination of the range of populations and purposes to more fully develop guidance. background: the majority of studies examining the relationship between residential environments and cardiovascular disease have used census derived measures of neighborhood ses. there is a need to identify specific features of neighborhoods relevant to cardiovascular disease risk. we aim to ) develop methods· data on neighborhood conditions were collected from a telephone survey of s, fesi· dents in balth:.ore, md; forsyth county, nc; and new york, ny. a sample of of the i.ni~~l l'elpondents was re-interviewed - weeks after the initial interview t~ measure the tes~-~etest rebab ~ ty of ~e neighborhood scales. information was collected across seven ~e ghborho~ cond ~ons (aesth~~ ~uah~, walking environment, availability of healthy foods, safety, violence, social cohesion, and acnvmes with neighbors). neighborhoods were defined as census tracts or homogen~us census tra~ clusters. ~sycho metric properties.of the neighborhood scales were accessed by ca~cu~~.ng chronba~h s alpha~ (mtemal consistency) and intraclass correlation coefficients (test-r~test reliabilmes) .. pear~n s .corre~anons were calculated to test for associations between indicators of neighborhood ses (tncludmg d mens ons of race/ ethnic composition, family structure, housing, area crowding, residential stability, education, employment, occupation, and income/wealth) and our seven neighborhood scales. . chronbach's alphas ranged from . (walking environment) to . (violence). intraclass correlations ranged from . (waling environment) to . (safety) and wer~ high~~~ . ~ for ~urout of the seven neighborhood dimensions. our neighborhood scales (excluding achv hes with neighbors) were consistently correlated with commonly used census derived indicators of neighborhood ses. the results suggest that neighborhood attributes can be reliably measured. further development of such scales will improve our understanding of neighborhood conditions and their importance to health. childhood to young adulthood in a national u.s. sample jen jen chang lntrodfldion: prior studies indicate higher risk of substance use in children of depressed mothers, but no prior studies have followed up the offspring from childhood into adulthood to obtain more precise estimates of risk. this study aimed to examine the association between early exposure to maternal depl'elsive symptoms (mds) and offspring substance use across time in childhood, adolescence, and young adulthood. methods: data were obtained from the national longitudinal survey of youth. the study sample includes , mother-child/young adult dyads interviewed biennially between and with children aged to years old at baseline. data were gathered using a computer-assisted personal interview method. mds were measured in using the center for epidemiologic studies depression scale. offspring substance use was assessed biennially between and . logistic and passion regression models with generalized estimation equation approach was used for parameter estimates to account for possible correlations among repeated measures in a longitudinal study. rnlllta: most mothers in the study sample were whites ( %), urban residents ( %), had a mean age of years with at least a high school degree ( %). the mean child age at baseline was years old. offspring cigarette and alcohol use increased monotonically across childhood, adolescence, and young adulthood. differential risk of substance use by gender was observed. early exposure to mds was associated with increased risk of cigarette (adjusted odds ratio (aor) = . , % confidence interval ( ): . , . ) and marijuana use (aor = . , % ci: . , . ), but not with alcohol use across childhood, adolescence, and young adulthood, controlling for a child's characteristics, socioeconomic status, ~ligiosity, maternal drug use, and father's involvement. among the covariates, higher levels of father's mvolvement condluion: results from this study confirm previous suggestions that maternal depressive symptoms are associated with adverse child development. findings from the present study on early life experi-e~ce have the potential to inform valuable prevention programs for problem substance use before disturbances become severe and therefore, typically, much more difficult to ameliorate effectively. the ~act (~r-city men~ health study predicting filv/aids, club and other drug transi-b~) study a multi-level study aimed at determining the association between features of the urban enyjronment mental health, drug use, and risky sexual behaviors. the study is randomly sampling foster sessions v neighborhood residents and assessing the relations between characteristics of ethnographically defined urban neighborhoods and the health outcomes of interest. a limitation of existing systematic methods for evaluating the physical and social environments of urban neighborhoods is that they are expensive and time-consuming, therefore limiting the number of times such assessments can be conducted. this is particularly problematic for multi-year studies, where neighborhoods may change as a result of seasonality, gentrification, municipal projects, immigration and the like. therefore, we developed a simpler neighborhood assessment scale that systematically assessed the physical and social environment of urban neighborhoods. the impact neighborhood evaluation scale was developed based on existing and validated instruments, including the new york city housing and vacancy survey which is performed by the u.s. census bureau, and the nyc mayor's office of operations scorecard cleanliness program, and modified through pilot testing and cognitive testing with neighborhood residents. aspects of the physical environment assessed in the scale included physical decay, vacancy and construction, municipal investment and green space. aspects of the social environment measured include social disorder, social trust, affluence and formal and informal street economy. the scale assesses features of the neighborhood environment that are determined by personal (e.g., presence of dog feces), community (e.g., presence of a community garden), and municipal (e.g., street cleanliness) factors. the scale is administered systematically block-by-block in a neighborhood. trained research staff start at the northeast corner of an intersection and walk around the blocks in a clockwise direction. staff complete the scale for each street of the block, only evaluating the right side of the street. thus for each block, three or more assessments are completed. we are in the process of assessing psychometric properties of the instrument, including inter-rater reliability and internal consistency, and determining the minimum number of blocks or street segments that need to be assessed in order to provide an accurate estimate of the neighborhood environment. these data will be presented at the conference. obj«tive: to describe and analyze the perceptions of longterm injection drug users (idus) about their initiation into injecting. toronto. purposive sampling was used to seek out an ethnoculturally diverse sample of idus of both genders and from all areas of the city, through recruitment from harm reduction services and from referral by other study participants. interviews asked about drug use history including first use and first injecting, as well as questions about health issues, service utilization and needs. thematic analysis was used to examine initiation of drug use and of injection. results: two conditions appeared necessary for initiation of injection. one was a developed conception of drugs and their (desirable) effects, as suggested by the work of becker for marijuana. thus virtually all panicipants had used drugs by other routes prior to injecting, and had developed expectations about effects they considered pleasureable or beneficial. the second condition was a group and social context in which such use arose. no participants perceived their initiation to injecting as involving peer pressure. rather they suggested that they sought out peers with a similar social situation and interest in using drugs. observing injection by others often served as a means to initiate injection. injection served symbolic purposes for some participants, enhancing their status in their group and marking a transition to a different social world. concl ion: better understanding of social and contextual factors motivating drug users who initiate injection can assist in prevention efforts. ma!onty of them had higher educational level ( %-highschool or higher).about . yo adffiltted to have history of alcohol & another . % had history of smoking. only . % people were on hrt & . % were receiving steroid. majority of them ( . ) did not have history of osteoporosis. . % have difficulty in ambulating. only . % had family history of osteoporosis. bmd measurements as me~sured by dual xray absorptiometry (dexa) were used for the analysis. bmd results were compare~ w ~ rbc folate & serum vitamin b levels. no statistical significance found between bmd & serum v taffiln b level but high levels of folate level is associated with normal bmd in bivariate and multivariate analysis. conclusion: in the studied elderly population, there was no relationship between bmd and vitamin b ; but there was a significant association between folate levels & bmd. introduction: adolescence is a critical period for identity formation. western studies have investigated the relationship of identity to adolescent well-being. special emphasis has been placed on the influence of ethnic identity on health, especially among forced migrants in different foreign countries. methodology: this study asses by the means of an open ended question identity categorization among youth in three economically disadvantaged urban communities in beirut, the capital of lebanon. these three communities have different histories of displacement and different socio-demographic makeup. however, they share a history of displacement due to war. results and conclusion: the results indicated that nationality was the major category of identification in all three communities followed by origin and religion. however, the percentages that self-identify by particular identity categories were significantly different among youth in the three communities, perhaps reflecting different context in which they have grown up. mechanical heart valve replacement amanda hu, chi-ming chow, diem dao, lee errett, and mary keith introduction: patients with mechanical heart valves must follow lifelong warfarin therapy. war· farin, however, is a difficult drug to take because it has a narrow therapeutic window with potential seri· ous side effects. successful anticoagulation therapy is dependent upon the patient's knowledge of this drug; however, little is known regarding the determinants of such knowledge. the purpose of this study was to determine the influence of socioeconomic status on patients' knowledge of warfarin therapy. methods: a telephone survey was conducted among patients to months following mechan· ical heart valve replacement. a previously validated -item questionnaire was used to measure the patient's knowledge of warfarin, its side effects, and vitamin k food sources. demographic information, socioeconomic status data, and medical education information were also collected. results: sixty-one percent of participants had scores indicative of insufficient knowledge of warfarin therapy (score :s; %). age was negatively related to warfarin knowledge scores (r= . , p = . ). in univariate analysis, patients with family incomes greater than $ , , who had greater. than a grade education and who were employed or self employed had significantly higher warfarm knowledge scores (p= . , p= . and p= . respectively). gender, ethnicity, and warfar~n therapy prior to surgery were not related to warfarin knowledge scores. furthermore, none of t~e. m-hospital tea~hing practices significantly influenced warfarin knowledge scores. however, panic ~ants who _rece v~d post discharge co~unity counseling had significantly higher knowledge scores tn comp~r son with those who did not (p= . ). multivariate regression analysis revealed that und~r~tandmg the ~oncept of ?ternational normalized ratio (inr), knowing the acronym, age and receiving ~ommum !' counseling after discharge were the strongest predictors of warfarin kn~wledge. s~ oeconom c status was not an important predictor of knowledge scores on the multivanate analysis. poster sessions v ~the majority of patients at our institution have insufficient knowledge of warfarin therapy.post-discharge counseling, not socioeconomic status, was found to be an important predictor of warfarin knowledge. since improved knowledge has been associated with improved compliance and control, our findings support the need to develop a comprehensive post-discharge education program or, at least, to ensure that patients have access to a community counselor to compliment the in-hospital educatiop program. brenda stade, tony barozzino, lorna bartholomew, and michael sgro lnttotl#ction: due to the paucity of prospective studies conducted and the inconsistency of results, the effects of prenatal cocaine exposure on functional abilities during childhood remain unclear. unlike the diagnosis of fetal alcohol spectrum disorder, a presentation of prenatal cocaine exposure and developmental and cognitive disabilities does not meet the criteria for specialized services. implications for public policy and services are substantial. objective: to describe the characteristics of children exposed to cocaine during gestation who present to an inner city specialty clinic. mnbods: prospective cohort research design. sample and setting: children ages to years old, referred to an inner city prenatal substance exposure clinic since november, . data collection: data on consecutive children seen in the clinic were collected over an month period. instrument: a thirteen ( ) page intake and diagnostic form, and a detailed physical examination were used to collect data on prenatal substance history, school history, behavioral problems, neuro-psychological profile, growth and physical health of each of the participants. data analysis: content analysis of the data obtained was conducted. results: twenty children aged to years (mean= . years) participated in the study. all participants had a significant history of cocaine exposure and none had maternal history or laboratory (urine, meconium or hair) exposure to alcohol or other substances. none met the criteria of fetal alcohol spectrum disorder. all were greater than the tenth percentile on height, weight, and head circumference, and were physically healthy. twelve of the children had iqs at the th percentile or less. for all of the children, keeping up with age appropriate peers was an ongoing challenge because of problems in attention, motivation, motor control, sensory integration and expressive language. seventy-four percent of participants had significant behavioral and/or psychological problems including aggressiveness, hyperactivity, lying, poor peer relationships, extreme anxiety, phobias, and poor self-esteem. conclusion: pilot study results demonstrated that children prenatally exposed to cocaine have significant learning, behavioural, and social problems. further research focusing on the characteristics of children prenatally exposed to cocaine has the potential for changing policy and improving services for this population. methods: trained interviewers conducted anonymous quantitative surveys with a random sample (n= ) of female detainees upon providing informed consent. the survey focused on: sociodemographic background; health status; housing and neighborhood stability and social resource availability upon release. results: participants were % african-american, % white, % mixed race and % native american. participants' median age was , the reported median income was <s , year, and % reported receiving a high school diploma or equivalent. women reported a number of health conditions rypical of underserved populations, including asthma ( %), sexually transmitted infections ( %), high blood pressure ( %), hcv ( %), diabetes ( %) and hiv ( %). nearly half ( %) did not anticipate having a place to stay for at least days upon release. factors significantly associated housing stability upon release were: high family support score (adjusted odds ratio [aor) . ; % confidence interval ( % cl) . , . ), high neighborhood stability score (aor . ; % cl . , . ), wanting a commercial sex worker (csw) support group (aor . ; % cl . , . ); and identifying as bisexual (aor . ; % cl . , . ). women desired employment ( %), housing ( %), education ( %), drug treattnent ( %), help with custody of children ( %), childcare ( %), and domestic violence suppon ( %) services. conclusions: female detainees represent one of urban centers' most marginalized pcjpwatioos. short periods of detention represent a unique opportunity for _interven?~ns bri~ co~s and public health institutions. service providers should collaborate ~ th local ~ails to .p~de a con uwnof care for female detainees upon release that includes transportation , housing, residential drug treallllcnt, employment, education, family reunification, childcare and domestic viol~nce su~rt. ~pecial attenlion is warranted to lesbian and bisexual women and csws, who may be especially margmalized &om family and service-based support networks. introduction: "health care and ethnic minority immigrants" examines how health care policy dil· ferences between canada and the united states impact the health-related hardships, access and use of preventative care, and health outcomes of urban ethnic minority immigrants in both countries. methods: the findings of this paper build on the results of my qualitative comparative study of hotel workers in vancouver, bc and seattle, wa that revealed greater health related hardships for similarly matched employees in seattle compared to vancouver. in this paper, i examine the generalizability of these findings at the cross-national level for similar ethnic minority immigrant groups. i compare the impact of health care policy differences on specific groups that have emigrated to cities in both canada and the united states. these include immigrants from china, viemam, philippines, west indies, africa, sri lanka, pakistan, and latin america. comparative statistical analysis -utilizing rel· evant data from statistics canada and the u.s. census -reveal the extent to which health policy differ· ences help explain how current health policy in the united states disadvantages urban ethnic minority immigrants. results: many ethnic minority immigrants are a part of the working poor, a group which disproportionately lacks health insurance coverage in the united states. their position in the labour market makes them most vulnerable to exclusion from health care services. the data reveals how current u.s. health policy creates barriers for recently arrived ethnic minority immigrants to access health insurance and care. it remains difficult to ascribe health outcome differences directly to policy differences because of the challenge in disentangling the complex interacting interventing variables, including income inequality, that determine health outcomes. yer suggestive evidence suggests that health policy in the united states is harming the health of urban ethnic minority immigrants. the current health policy regime in the united states harms the health access, care, and outcomes of urban ethnic minority immigrants. comparing the fortunes of similar immigrants in cana· dian and u.s. cities reveals these patterns of disadvantage and some of their consequences. these barriers are an understudied factor in the sociological literature on "segmented assimilation" and social exclu· sion. the paper ends with policy recommendatio ns to improve access to health care among ethnic minor· ity immigrants in both countries, with the goal of reducing health related hardships, and improving health outcomes. mass index deyu pan, richard baker, and keith norris badtgrou~ over the past decades, there has been dramatic increase in prevalence of obesity in the us population. however, the relationship between obesity and the prevalence of cardiovascular dis· ease (cv~) risk factors in different race/ethnic groups over time is not well known. . ik~rgn: _we use cross-sectional , nationally representative surveys: national health and nutri· t nal examination survey (nhanes iii - (n= ) and nhanes nhanes - , including white, black, and hispa~ic races who were no~preg~ant, aged to years. res lt : the preval~nce of high cholesterol level (~ mg/dl), untreated high blood pressure ( : l / mm hg) an~ diabetes were calculated according to bmi group (lean, < ; overweight, - ; and obese, : ) for different race/ethnicity groups. over the approximately years period (from l ~ ~o [ ] [ ] [ ] [ ] , reducrion in cvd risk factors in non-hispanic white has been observed. for mmonty race/~hnicity groups, black and hispanic, there had been increases in prevalence in high blood fa pressure and diabetes. the lean group experienced larger increase in prevalence of those cvd risk ctors. . fo~~ the prevalence in cvd risk factors over time had reduced in most of the bmi ca egoes r t e w ~~e population. however, for black and hispanic, prevalence of of cvd risk factors ave generauy uncreased, especially in overweight and obese groups. methods: strategies identified to achieve these goals include: developing meaningful neighbourhood and district boundaries for comparing health information, providing free access to neighbourhood health profiles (including relevant data at the smallest level for which valid rates could be calculated); mapping relationships of inequality at a variety of nested levels; providing a range of formats (maps, tables) to meet the needs of users; providing technical support; seeking user input to advance and improve the site; and conducting workshops to foster access and use of data for decision-making , advocacy and collaboration. an evaluation strategy is being developed to assess the efforts and impact of these strategies. a preliminary assessment of the results of the first six months of activity will be completed in october . results: significant differences in health are shown at all the geographic levels indicating success in developing the boundaries. results tabulated for the first six months use of the site include: site visits; media use; reference/acknow ledgement of the site in other documents; number of contacts through presentations and workshops; feedback from users identifying strengths and limitations; and, response from health decision makers. members of the partnership are identifying additional tools and services to further support actions that reduce health inequalities. the assessment will be used to develop more specific goals, targets and monitoring mechanisms. conclusions: our experience with paper-based health profiles indicates that they have been used extensively for program planning and advocacy. the greater availability of information in a publiclyavailable web-based format is expected to translate into even greater usefulness and wider application. the web site has had considerable usage to date, extensive media coverage. site users and workshop participants have provided positive feedback and suggestions for next steps. the six month review will be available in october . in india, more than and a half people are hiv-positive and half a million have aids. india currently has the largest number of positive people in the world, oumumbering south africa and accounting for nearly one tenth of the global hiv/aids prevalence. the world bank predicts that by , there will be million hiv/aids cases in india. the central challenge facing hiv prevention efforts in south asia today is learning how to respond to the societal determinants of vulnerability to hiv. hiv/aids is an issue largely engulfed by social stigma. stigma and discrimination are often considered the foremost barriers to effective poster sess ns v prevention and care initiatives. stigma can make a person afraid of disclosing their status~ ~yone el se, and may make them feel depressed or alone. stigma can .also le~d to poor adherence to medicanon, ~ likelihood to access health and social services, and less desire to hve. hiv+ men and women may beafraidtotd! their co-workers that they have hiv for fear of their reactions or for fear of losing their jobs. in a study conducted of people living with hiv/aids in delhi, india ov~r. -~, many respo~ts shared their experiences of discrimination in their families, in their communmes, an~ m health ~e settmgs. these findings will be shared in the workshop, and will be compa~ed to m~ ex~nences workmg as an ~ co~l~ at the center for aids prevention studies in san francisco, cahforma and congreso de lannos unidos m philadelphia, pennsylvania. the workshop will include an overview of hiv/aids in urban contexts in tht united states (los angeles, san francisco, new york, philadelphia) and south asia (delhi, hyderabad, chennai). differences in methods for outreach, prevention and treatment efforts between devdoped world and developing world contexts will be discussed. a large portion of the workshop will be centered on discussion. participants will engage in an exercise to categorize their ideas of stigma. the workshop will also include a powerpoint presentation on the quantitative data gathered from the survey. the number of homeless and runaway youth is increasing in toronto, which is currently home to out of youth in the gt a who live alone, and it is the preferred locale for the street-involved and homeless youth. the city's youth population is expected to grow by nearly % by , the school dropout rate is rising, and there are is a paucity of empirical data on what works with these at-risk youth. over a two-year period, ( ) ( ) ( ) , youthlink-inner city, conducted an evaluation of the impact of a harm reduction program aimed at reducing street youth's risk of contracting/infecting others with the hep c virus, which has both short-term and long-term deleterious effects. demographic data from street-youth, along with resources/services used, employment methods, type and frequency of drug use, health status, police contacts, and their views of program impact were analyzed using a standardized sur· vey. additionally, focus groups with youth, agency staff and community key informants were conducted, as well as in-depth interviews with three youth, over a sixth-month period. this paper details study results, which both inform both practice and future study about what works, why it works, and how best to work with these vulnerable youth. sho~ed .that the wasteland in this area was contaminated by as cd zn pb cu simultaneously. the con-ta~matton of as ~d was quit significant. the contamination problems and environmental issues in this region are very. serious. the awareness on environmental and health issues was investigated by spot survey and analysis. overall awareness among the residents in the region is very poor. the measures must be taken to assu~e t~e .sustainable economy development by local and central gorvernments. keywords nandan guangx ; mmmg area; environmental awareness. concern like, epileptic fits, vision problems, earache, cough of more than weeks and urinary problems. ninety-five subjects did not take bath regularly and were exposed to sex. the health problems identified are only of a particular point of time and it may be difficult to interpret the depth of "iceberg" of the street children's world also draw the health-illness continuum. periodic interaction and follow-up is very difficult as they generally disappear from the research setting due to their frequent mobility for survival measures. as per the prediction of the iceberg theory, only some problems may have been identified, larger problems in respect to their health may not have been identified. in spite of various limitations, this attempt had proven that, it is possible to enter the street children world, explore the iceberg of illnesses, and establish data of health-illness continuum through an effective nursing agency. it is recommended to deworm these children, provide nutritional education, establish "condom corners" and "street children help line" in the city and urban slum areas and undertake action research on their health. malnutrition is a serious problem in developing countries like bangladesh. malnutrition causes a great deal of child suffering. malnutrition is one of the major causes of morbidity and mortality among the child. the aim of present study was to investigate the nutritional status and its relation to socioeconomic conditions of urban disadvantaged child of under five years age. nutritional status was determined by anthropoemetric measurement(heig ht, weight, mid-arm circumference etc.). determination of total protein and serum albumin were done for biochemical examination. haematological examination was done by blood haemoglobin profile estimation by cynmethhaemoglob in method and determination of haematocrit value or packed cell volume (pcv). stool examination for ova of hook worm, round worm, trichuris species and other species were also done. relevant information on socioeconomic characteristics was recorded by interviewing the house hold head using pretested questionnaire. our study demonstrated that nutritional status of the children are positively correlated with family income, parents level of formal education and negatively related to the family size. the effect of family income on the nutritional status, haematological and biochemical indices of urban disadvantaged child under five will be discussed in detail which will help us to determine proper way of utilization of health care facilities exists in developing countries. introduction: with the increase in morbidity and reduction in mortality and with the introduction of highly active antiretroviral therapy (haart), there is increasing focus on the determinants of healthrelated quality of life (hrqol) in hiv-infection. the focus on the present study is to examine the relationship between social support, depression, and hiv disease severity, and the extent to which these variables impact on hrqol in adult men with hiv-infection. methods: as part of a larger ongoing natural history study focusing on the neurobehavioural complications of hiv and aids, we administered questionnaires to assess depression (beck depression inventory), social support, and hrqol (mos-hiv) to adult men with hiv-infection. a structured interview was used to collect health information and data on hiv disease severity. physical and mental health summary scores (phs and mhs) were derived through principal components analysis. participants were grouped according to level of social support: "well supported" (n= ), "moderately supported" (n= ), "little or ineffective support" (n= ). analysis of variance was conducted to assess the effects of three levels of perceived social support, depression status (present vs absent), and hiv disease severity (aids vs non-aids) on mental and physical health dimensions of hrqol. potential interaction effects were also evaluated. results: social support was found to have a significant effect on both mhs and phs. presence of depression was found to have a significant effect on mhs but not phs. hiv disease severity (presence of aids diagnosis) was found to have a significant effect on phs but not mhs. manov a analyses revealed no significant interactions effects. conclusions and implications: level of social support, presence of depression and hiv disease severity were shown to have independent effects on hrqol. feeling "well supported" appears to have significant benefits for mental and physical health. biological indicators of hiv disease appear to have a selective impact on physical health while presence of depression is related to significant reductions in mental health. the development and evaluation of behavioural interventions to improve perceived social support network and depression will likely result in significant improvements in health outcomes of adults with hiv and aids. introduction: ongoing medical advances have greatly enhanced the longevity of penons living with aids (plwa). however, for certain subgroups living with hiv/aids, including, members of minority groups, women and the economically underprivilege d, aids outcomes have not changed so favorably. one obvious factor to consider when explaining disparities in aids outcomes is the environ· ment within which an individual resides. few studies of aids outcomes have focused on how commu· nity setting influences the effectiveness of care delivery. the principle research questions were: ) what is the relationship between the locations of areas with concentrations of pl wa and the distribution of both primary and ancillary service providers? ) how has the widespread availability of haart (after ) impacted aids outcomes at the community level? ) how do aids mortality and fatality rates vary when related community characteristics, such as household income, ethnic mix, and geographic access to primary and ancillary hiv/aids services are considered? we examine this issue across residential communities in the los angeles area. methods: los angeles county's comprehensive aids service providers database (compiled and maintained by aids project los angeles) was geo-referenced and distances between weighted mean population centers and the nearest hiv/aids service providers were calculated to provide a measure of access which was then merged with aids diagnosis and mortality data along with relevant socioeconomic and population indicators and for analysis using bivariate and multivariate statistics at the zip code level. results: there is a growing disparity in hiv/aids outcomes between low-income minority areas and affluent non-minority areas in the post-haart era (p = . ). ancillary aids services such as case management and counseling and testing are located near the places where low income hiv/aids service consumers are likely to live (p =. ). in spite of having more access to ancillary services low income areas continue to be associated with smaller decreases post-haart aids mortality rates (p= . ). conclusions: given the increasing disparities in aids outcomes between lower and upper income communities in the post -haart era, more specific research into the capacities of aids services providers and the efficiency of their interventions is required. although it is clear that ancillary services are operating in the areas of greatest need, their effectiveness remains limited. understanding the reasons for t~is, be they lack of adequate resources for inner city service providers, failure to reach target popula· tmns or other causes, requires additional research. in ? , y.out~ who were able to speak either french or english and had been absent from their parent's/ c~regivers ~es. dence for at least three consecutive nights took part in the survey which consisted of inter· viewer-adm ms tered question~aires. p.arti~i~an~s were recruited from drop in centres in cities across <?-nada.y~uth self-report as either using in ect on or non-injection drugs. statistical analyses were car· r ed out using sas version . the 'home' is a contested site for many women living in urban areas. women living in poverty and using illicit drugs are largely excluded from participation in dominant 'home-base' gender roles of wife and mother because of economic disadvantage. they thus 'make home' in ways that are specific to their everyday experiences. while research has established links between housing, health and drug use, this literature does not tend to consider the meanings that home may have within the lives of women who lack access to adequate tenured living spaces. this presentation reports the findings of my master's thesis work. using grounded theory methodology within a poststructuralist feminist conceptual framework, i conducted in-depth, open-ended interviews with women living in the toronto area. the women were recruited from within the community through posters at different social service agencies (e.g., drop-in centres, community health centres). they were asked to describe their housing experiences and what home meant to them over the course of their lives. through the data analysis process, a substantive theory of 'making home' for women living in poverty and using illicit drugs emerged. the central concept of making home is a continual process of learning about and interacting with the environment. the process of making home entails different subprocesses: finding home (knowing what is available and accessible, and accessing home), adaptation, and leaving home. the different meanings of home that women developed from their experiences and knowledge emerged as critical components for the process of making home. the women i interviewed were very mobile and experienced constant change with regards to home. home was not considered only in relation to physical living space. home could be made within a relationship or with regards to a possession. while dominant meanings of home relation to tenured living spaces are generally positive, my research indicated that home could also be a negative context. the presentation will describe my research process and findings as well as the theoretical and policy implications of my results. in the western democracies, social citizenship bundles the right to social provision (defined as a share of the social good, not necessarily proportionate to the market value of a citizen's contribution) with participation in the paid labour force. for this reason, social citizenship rights, which usually involve some kind of redistributive measures, are a key mechanism by which states ensure economic equality, or at least, economic equality of opportunity, but are also a mechanism of social exclusion. social rights are inscribed around a single kind of relationship, that which exists between a male family breadwinner and the paid labor market; those who make economic contributions that fall outside this relationship -such as unpaid care-work, or, work that occurs in shadow or underground economiesare to a greater or lesser degree barred from accessing citizen-based social provisions. furthermore, social provision that occurs outside of the breadwinner/market-eco nomy dyad is very often meanstested and is accompanied by regulatory state apparatuses (this includes a range of social services, from welfare payments, to child-care subsidies, to disability pensions). social citizenship is thus stratified; the legal relationship that is at the heart of social citizenship acts as a form of social closure against claims for a share of the social good made by those who are 'lesser' citizens than others. of particular interest in this paper is how citizenship inequalities translate into inequalities in the social provisions that emerge from economic participation: the right to safety on the job, protection from employer harassment, protection from the vagaries of the market as well the right to adequate, comprehensive, and appropriate health services. drawing on mixed methods, longitudinal data from adult sex workers (n= ) located in two research sites with different social welfare regimes -one in canada and one in the u.s. -we examine the consequences of working in a "shadow" or "underground" economy on various facets of health and access to health services, taking into consideration the mediating role that citizenship constructs and social welfare regimes play in accessing other key social and economic determinants of health. methods: the study population included methadone patients (re)admitted at the mhs in the period from / / to / / , born in the netherlands, morocco, surinam, dutch antilles or turkye, and officially registered in the population register of amsterdam. the population register was used to ascer· rain the vital status. causes of death were provided by the central bureau of statistics. mortality was categorised as hiv related, directly drug related (overdose) and other.mortality. results: the methadone patients had the following characteristics: years of age at entry; % male; % ethnic minority; % ever injected. in total, personyear (py) of observation time and deaths ( % hiv related, % overdose; % other) were observed. hence, the crude mortality rate was / py ( % ci - / py). the percentage of (ever) injectors was higher among the native dutch than among the ethnic minorities, % and % respectively. higher rates were observed among native dutch drug users compared to those belonging to an ethnic minority (age adjusted hazard ratio (hr) . ( % ci . - . ). the age adjusted hr of (ever) injecting drug users versus non injecting users was . ( % cl . - . ). after additional adjustment for route of administration a non significant difference between the dutch and ethnic minorities remained (hr . , % cl . - . , p-value . . conclusion: the mortality rate among the heroin users in amsterdam is strongly affected by the high prevalence of non-injecting drug use. moreover, this study confirms that differences in mortality between the native dutch and the ethnic minorities is related to differences in route of administration. the ongoing reduction of injecting drug use (due tot selctieve mortality, and switching route ofadministration and popularity of crack cocaine) may lead to a further reduction of mortality rates among heroin users in amsterdam. interventions preventing the initiation of injecting should be encouraged. . introduction: food insecurity is an inequality that is central in the lives of many low-income cana· d ans. people lack food security when regular access to nutritious food is limited or variable due to high prices'. low income, lack of transportation or inadequate food distribution, or they become disadvan· taged m other w~ys through the acquisition of food. a group comprising academics, health profession· als, and commumty workers who have experience in food insecurity, developed a pilot study in ottawa that sought to und~rstand the lived experience of food insecurity. the study also used the united states department of agriculture (usda) community food security module. methods: a series of group meetings determined the best research approaches; questionnaires and consent forms were developed by a working group. twenty-three self-identified food insecure respon· dents were interviewed. the data were analysed using frequency distributions· the food security module was coded according to the usda coding guide, and open-ended responses w~re coded using a grounded approach. renlts: preliminary results from our pilot study have given the research team cause for considerable concern. out of households without children, experienced food insecurity with hunger; ~ere at the severe l~vel. out of households with children, experienced food insecurity with hunger. ~•rst person reflecnons commonly featured feelings of depression low self-esteem and despair. participants' account tha d . an cu ty gettmg to the store, severely limited putting knowledge and skills mto practice. l'oster sessions v conclusion: based on these early findings, our research team is looking to challenge what appear to be assumptions about poverty and food insecurity and for best ways to use this information. some policy approaches and interventions that encourage people to eat better and exercise more, may be missing the mark for low-income individuals, and may serve to maintain food insecurity. future research will build on this pilot. with methods augmentation, and a comprehensive knowledge dissemination plan, we hope co contribute to research and policy frameworks at all levels. ps- (a) mental health and the corrections system: population-based analyses in urban, semi-urban, and rural settings julian somers, robert watts, and michelle patterson introduction: according to recent epidemiological research, rates of mental disorders vary considerably across countries and across regions within countries. nevertheless, rates of mental disorders (including substance use disorders) are consistently higher in populations involved in the corrections sys- em. courts have long recognized the heavy burden of mental illness within their purview, and have developed innovative programs to better manage the needs of such individuals. the majority of these innovations (e.g., specialized courts) exist in urban settings. however, few studies have examined the degree of variability in rates of different mental disorders between courts in urban and other settings (e.g., semi-urban, rural). variability between courts in different settings, if present, holds implications for needs-based resource planning. the present study was conducted as part of a long-term inter-ministerial collaboration in british columbia (bc). analyses were conducted on linked administrative data regarding population health and correctional services. a database was constructed including all individuals sentenced in bc in a single year (n= , ). corrections records were matched to records of health services utilization (hospital and outpatient services) for mental disorders and substance use disorders in the years preceding sentencing. services for mental health and substance-related problems were aggregated into three groups: severe mental illness (smi); less-severe mental illness (lsmi); alcohol/other drug (ad). courts were grouped, based on their annual volumes, inro three categories: "urban"; "semi-urban" and "rural." rates of service use for mental disorders were compared between groups for -year and -years preceding sentencing. results: there were significant differences in the rates of mental disorders in courts of different size (urban, semi-urban, rural) . however, differences between the rates of disorders within each of these groups exceeded the discrepancies between groups. comparatively high and low rates of disorders were observed in courts of each size. moreover, the courts with the highest rates of certain disorders (e.g., ad) did not have the highest rates of other types of mental disorders (e.g., smi). conclusions: rates of mental disorders differed significantly among the annual populations sentenced across courts in bc. urban courts (which process comparatively large numbers of people) have implemented services to address the needs of the mentally ill. the present analyses strongly suggest that program development should be closely linked to the demonstration of need. the results caution that a uniform approach to court programs for the mentally ill is likely to be inefficient, over-supplying services in some settings and underestimating need in others. results: public settings used for injection are characterized by highly unhygienic conditions, the presence of unsafely disposed syringes, limited availability of sterile syringes and a lack of sterile water for injecting. a number of unsafe injection practices observed were common among public injectors. the presence of police officers nearby and the potential of assault by street predators fostered rushed injecting among those consuming drugs in public spaces. the ecological features of these environments encourage unhygienic and unsafe injecting practices, heighten risk for overdose and the transmission of blood borne viruses. introduction: approximately % of women experience depression in the first weeks or months after giving birth. although it has been argued that postpartum depression (ppd) is a culture-bound p~ nomenon, experienced only in western, industrialized countries, recent international research studies have confirmed that the prevalence of ppd is similar around the world. however, little is known about variables that may influence the experience of ppd in women from diverse cultures and immigrant women. research is needed to identify the role culture may play in the presentation of ppd (i.e., types of symptoms most commonly reported), how women from various racial, ethnic and cultural backgrounds perceive and attribute their symptoms of ppd, and finally, how culture can be appropriately addressed in ppd treatment programs. method: to examine the role of culture in ppd, semi-structured interviews and self-report question· naires were administered to clients of the women's health centre of st. joseph's health centre, tor· onto. participants were identified as either first generation canadians (relative newcomen) (n= ) or second generation canadian (parents were immigrants to canada) (n= ). data were collected qd these two groups of women based on: severity of depression, symptom presentation, perceived role of social supports and culturally-specific traditions, and barriers and responses to treatment. the interview data were analyzed using qualitative methods (thematic content analysis), and the following themes were identified: ) stress about passing on their culture to their children, ) lack of social support and feelings of isolation, ) perceived importance or lack of importance of cultural based tra· ditions, ) conflicts with family members. about cultural traditions and beliefs, ) mental health stigma within ethnic communities and beyond, ) race-and sex-based discrimination, and ) language barriers. conclrllion: identifying the role culture plays in the presentation of ppd, and how women from diverse backgrounds perceive and attribute their symptoms of ppd, is critical in order to establishcultur· ally appropriate guidelines for treatment options. furthermore, information gathered from this study can be used to develop policies and resources for delivering culturally competent care for newcomer wo~ who are dealing with ppd as well as the issues around acculturation (i.e., language barriers, racism). llus is of particular importance for urban health centers which provide postpartum care to diverse groups of women, and particularly recent immigrants or newcomers. ps-~ (al. contaminated 'therapeutic landscape': perceptions of the aamjiwnaang fint nation keyln smith and isaac luginaah . in~: this. paper pres;ents the findings of an ongoing study among the aamjiwnaang f!rst nanon. aam wnaang is located m the heart of samia's 'chemical valley', surrounded by cherrucal ~(ants such as esso, imperial oil, shell, suncor energy, and canada's largest hazardous waste disposal sate. safety kleen. this fint nation community is located within the st. clair river •area of concem'. as destgna~ by health canada for the population of samia and the surrounding region. although this comm_umty, by way of. its proximity to the numerous chemical plants is already exposed to high levels pollu~on, recent che?ucal dumping in ~mjiwnaang, as well as a failed proposal for another ethanol plant m the community, only helped to mtensify community concerns about potential health impacts of exposure. research on the cultural beliefs and traditions of first nation communities has established that th~ ~isting rel~tionship between first nations people and 'mother earth' is not only physical, but also_ spmtual. in this study we explore how the complex relationship between the aamjiwnaang first naaon and 'mother earth' be ha · · · i .. may c ngmg a contammated 'therapeutic' landscape. the study a so ~lores h?w aam wnaang residents are coping with these changes and with the probable conramina· boa of their community. ra!jts: aamjiwnaang residents acknowledge that they are living in a contaminated environment and are being impacted by emissions from the surrounding 'chemical valley' especially for future generations, and have expressed concerns that members of the community and mother earth are 'sick' as a result of this exposure. while moving from that 'place' has been discussed, residents have strong personal and generational connections to the land and insist however, that aamjiwnaang is their 'home' and will remain that way despite growing community concerns about the impact from industry. the contribution of this study lies in the direct involvement of community leadership in designing and conducting this research and distributing the results to further local policy development regarding community concerns on the reserve. background: truck driver are at very high risk for drug abuse because the factor contributing to drug abuse among driver are multiple. it is important to gain an understanding of the key factors that contributing to drug abuse among truck drivers. methods: seventy-truck driver aged - years were conveniently selected from the population. all the participants were male. an interview schedule was developed in the light of literature data and data were collected by personal interview with informed consent in selected urban area of eastern part of nepal. results: a considerable percentage of truck driver have less knowledge about drug abuse, its effect on body and their complication. majority of the participants ( %) explained that lack of education, financial crisis were leading factors of drug abuse. the average numbers of respondents were believed that lack of meaning in life, marital disharmony. friendship with drug abuser, stress, tiredness, modernization of life pattern and freedom from the home pressure were the influencing risk factors to drug abuse. conchuion: this study reveals those truck drivers are at risk in urban area for developing drugs abuse, mostly influenced by social and environmental factors. hence, these groups should undergo certain educational programme to prevent not only drug abuse, but also prevent transmission of infectious disease among these groups. introduction: food insecurity is an inequality that is central in the lives of many low-income canadians. our group of university researchers, health professionals, and community developers conducted a study in ottawa with community workers who work with people identified as food insecure. the purpose of the study was to understand the nature of their work, and their perspectives, perceptions and experiences of the causes and consequences of food insecurity. (a parallel study was conducted with food insecure participants). methods: sampling was through local knowledge of organizations involved in the provision of food to community members. written permission for the researchers to contact workers in confidence was obtained from each organization. thirteen in-depth interviews were conducted. the interviews consisted of a number of open-ended questions. the data were collated, and analysed using a grounded approach. results: workers interviewed represented organizations that offered diverse programming and methods of food distribution intended to address the needs of the community. the provision of food was seen as a necessary response to address hunger that arose for the majority from poverty caused by low income, or levels of government income support and safety nets that were insufficient to support food requirements. workers reported that food requirements varied according to different. ethnic backgrounds, ages of recipients and family configurations, and with food preferences, and d'.etary (health) requirements. workers' observations of the effects of insufficient food on adults and children such as depression, low energy and non-participation or social disengagement matched those of food insecure respondents. food insecurity was cited as "another srressor among the mountain of problems." overall, workers presented a picture of a silent, stigmatized, poor population including children, and a lack of advocacy to address the issues. be tha th · ·ty the results suggest that workers and organizations, like the commuruty mem rs t ey msecun • · · · · f ilab'l' f food · t d ·n thei·r ab 'l 'ty to address food insecurity. l m tanons m terms o ava ty o , serve, are restnc e . . funding, and donations appeared to set the para? eters of pr~g:am r.espon~ to commuruty food msecurity. workers were concerned with program des g": and a~m mstranon that m general addr~d hunger on an emergency short-term basis, although food msecunty was long-ter_m for ~any. sustainable solutions that include knowledge translation strategies, and health and social pohcy responses were suggested and will be explored in future research that hopes to build on this pilot. background: socioeconomic deprivation as well as low levels of soc!al s.uppoi:r have .been associated with poor outcomes following cardiac surgery. pre-operative depression m ~anents with coron~ry artery disease awaiting cabg ranges from - % and is an independent predictor of post-operanve mortality. since st. michael's hospital has a large inner city population, this study was designed to determine the both the prevalence of depressive symptomatology (ds) in patients awaiting cabg as well as its relationship with socioeconomic status (ses) and social support. methods: consecutive patients referred for isolated cabg were invited to complete the centre for epidemiological studies depression scale (ces-d) as well as a social support scale and a life stressors inventory. a ces-d score of : represents mild ds and a score of : represents moderate to severe ds. participants also recorded information on functional status, perceived progression of heart failure, demographic and ses variables. all participants with ces-d scores : were considered to have ds. results: of the patients ( %) who returned the survey, ( . %) of participants had a ces-d score : with ( . %) of those having scores suggestive of severe depression. females and those with ongoing medical concerns tended to have more ds (p= . and p= . respectively). age was not related to ds. perceived worsening of symptoms and increased ccs angina class were significantly related to the presence of ds (p= . and p= . respectively) but not the number of diseased heart vessels. satisfaction with personal relationships including having someone to confide in (p= . ), feeling lonely (p= . ) and not having a partner (p= . ) were significantly related to ds. being very upset by a recent breakup in the immediate family was also significantly related to ds (p= . ). having greater than a grade education was the only ses variable related to ds (p= . ). multivariate logistic regression suggested that not being partnered and having low education were the most significant predictors of ds. conclnsion: pre-operative depression is present in at least one quarter of patients referred for cabg. since ds is related to poor outcomes following cabg, single patients with few social supports and low education should be considered at high risk for ds. these findings support the need for the development of supportive interventions in patients at risk in order to decrease post-operative morbidity. this study examines the relationship between childhood sexual abuse, sexual assault during adolescence, and hiv-risk-related behaviours in a sample of homeless youths. over the past decade, there has been increasing research devoted to the impact of childhood sexual abuse. some studies have suggested that the experience of childhood sexual abuse is associated with substance use and abuse, at· risk sexual behaviour and subsequent higher rates of hiv infection (ompad et al., ; cinq-mars et al., ; brown et al., ) . other studies have found that childhood abuse, especially sexual abuse, is c_o~n among stree~ youth (noell et al. ). this study compares sexually abused males and females livtng on the street ~th non-sexually abused street youth, with regards to unsafe sexual behaviours and e~ures to potmnal t:dv sources (e.g., tattooing, body piercing and injection drug use). the hypothe-sis oft~ ~nt study is that the prevalence of hn-risk-related behaviours will be higher among street youth vtctuns of sexual abuse than those who have not been sexually abused. the sample includes youths aged to who met specific criteria's for itinerancy ( male and female, with a mean ~of . y· and a standard deviation of . ). they were recruited through five organisations working ~th~ you~ and were~ of an ongoing cohort study. all youth completed a to minute ques· ~onnaue on their sexual behaviours, use of drugs and alcohol and other hiv risk behaviours. oral spec· unens for hiv testing were. also collected. a total of ( . %) youth reported at least one incident of ~i •~use/assault ( ~ girls ( . % of all the girls) and boys ( . % of all the boys]). preliminary descnpnve analyses pomt to sexually abused/assaulted youth showing the highest prevalence of sexual poster sessions v at-risk behaviours. for example, . % of sexual abuse/assault victims have engaged in prostitution in their lives compared with . % in the non-sexually abused/assaulted group. in addition, . % of sexual abuse/assault victims reported having injected drugs, compared with . % in the non-sexually abused/assaulted group. more statistical analyses will bring other significant factors to light, especially when we analyze separately those victim of childhood sexual abuse as compare to those victim of sexual assault after childhood. elucidating the risk factors for getting involved in hiv-risk-related behaviours is important for the development of comprehensive and appropriate prevention and treatment intervention strategies. introduction: new immigrants and refugees to canada frequently emigrate from regions of the world where intestinal parasitic infections with worms are endemic. of note, some of these parasites area capable of surviving for years to decades within a given host and can have life threatening consequences many years after initial infection. thus, early diagnosis and treatment of intestinal parasitic worms is considered important in high risk immigrant populations, however there remains a lack of consensus regarding the best method of accomplishing this. diagnosing worm infections through stool examinations is costly and has limited sensitivity, while presumptive treatment of all immigrants, although advocated by some, is expensive and results in healthy individuals being unnecessarily treated. herein, we examine the utility of a hematologic marker (i.e. peripheral blood eosinophilia) as a screening instrument to identify parasitic worm infections in new immigrants to toronto. we identified adults, years of age or older, who were screened for intestinal parasitic infections by stool examination as part of a recently developed screening protocol at a downtown toronto community health centre. we examined the prevalence of infections with worms and subsequently evaluated the impact of several demographic factors on the presence of worm infections. we also determined the sensitivity and specificity of peripheral blood eosinophilia (defined as greater than eosinophils per ml) as a marker for intestinal parasitic worm infections. results: overall, % of the immigrants tested had evidence of at least one worm infection on a single stool examination, while % of such individuals bad infections with multiple worms concurrently. age did not appear to be associated with the presence of worms, however % of males had evidence of worm infections compared with % of females (p= . ). immigrants from asia, sub-saharan africa, and central america had the highest burden of overall infection. the sensitivity and specificity of peripheral blood eosinophilia for worm infections was % and % respectively. conclusions: one in five recent immigrants presenting to a community health centre in downtown toronto had evidence of at least one intestinal parasitic worm infection. the highest burden of illness was in men and in those emigrating from less developed regions of the world. peripheral blood eosinophilia is a poor screening test for worm infections however its presence is highly suggestive of the existence of worms in new immigrants. more than a decade ago, the journal of american college health recommended that a national study be conducted to measure the health status of african american college students, 'both health disparities and [their] positive healthful behaviors' (fennell, ) . it was later decided that when exploring the level of health risk behaviors for african american students, gender is an important variable and should be included in the research (fennell, ) . at historically black college and universities (hbcus) college health researchers must tackle gender disparities through highly-effective health promotion and disease prevention programs. the purpose of this review is to examine the literature that addresses the overarching health behaviors (i.e. risky sexual behavior, poor diet, smoking, physical inactivity, etc.) of african american men who attend hbcus. despite the various social, cultural, and academic benefits of african american students who attend hbcus, the number of research studies that adequately address their health and health behaviors is limited. studies indicate that african american men who attend hbcus are actively engaged in poor health behaviors. compared to females at hbcus, african american men are more likely to behave in ways that could result in injuries and the use tobacco, alcohol, and ~ther dru~. the city of toronto has recently proposed to conduct a street count of the homeless. like proposals that have come before, this most recent proposal is controversial among many homeless advocates and service providers because it is perceived as intrusive, likely to undercount the target population, and unnecessary for addressing the problem. advocates of the count view it as necessary to gauge the scope of the problem and advise city leaders about how to most effectively direct resources ro.the various homeless services. this paper first reviews the history of efforts to count homeless populat ns m toronto, describing the motivations and arguments of people on both sides of the issue. second, the paper reviews the methodological complexities of counting homeless populations, describing approaches that use shelter-counts, administrative data and street observations. those interested in counts for toronto and elsewhere can benefit from this review of approaches that have been proposed and carried out in other municipalities. third, the paper proposes a new community-base d strategy that joins the skills of methodologists, local experts, and service providers to ensure a fair and accurate count. the method of systematic social observation avoids some of the problems of early counts by utilizing a repeated identification approach to minimize undercount bias. the method also has the advantage of involving and compensating homeless individuals for assisting with the street count estimates. the estimation approach can be implemented on a rolling basis throughout the year. drug transitions) is a multi-level study aimed at examining the associations between features of the urban environment and mental health, drug use, and risky sexual behaviors. research participants are being recruited in new york city (nyc) neighborhoods. an essential first step in the implementation of this study was to delineate boundaries for each target neighborhood that could then be used to establish sampling frames and as key units of analytic interest. although many neighborhood studies rely on pre-established definitions (e.g. those used for the census or administrative purposes), such definitions do not always reflect contemporary settlement patterns. we felt that street level observations were a neces· sary component of the definition process. methods: the procedures used to delineate neighborhoods were: ( ) development of census block maps of targeted areas; ( ) review of land use maps and census tract data to ensure, prior to going into the field, tha.t particular blocks are residential and likely to have sufficient population for recruitment purposes; and ( ) field vislts and observation in each of the targeted areas. field observations focused on: housing characteristics, including housing type and condition; characteristics of commercial areas, such as likely customer base (e.g. local or no~, socio-economic status and ethnicity of customers); pedestrian volume (including con· gregauons of people m parks and outside stores or residences); obstructions to pedestrian traffic (e.g. ma or thoroughfares, multi-block industry or institutions); and maintenance and use of open spaces. results: in making the final decisions regarding neighborhood boundaries and the inclusion or exclusion of particular. blocks, we considered a broad range of factors including evidence of homogeneity an~ heterogeneity (socmeconomic, ethnic, housing type, environmental) across blocks within and blocks ad acent to a nei.ghborhood, and across the sample neighborhoods; the potential for efficient recruit· ment of appropriate particip.ants (i.e. sufficient local pedestrian traffic); and boundaries used in reporting census data (s? that population data can be used in our analysis). . altho~gh utilization of field observations for neighborhood definitions is relatively time consuming (ap~~ox mately hours for a block area, with more diverse neighborhoods taking even longer), we annc p~t~ that it will substantially improve the quality and consistency of our data gath· ~rmg ~nd analyse~. spec f c e?'amples from neighborhoods defined through this process will be given dur· m~ this presentatmn. we will also discuss the merits and limitations of characterizing neighborhoods usmg street level observations. has been no consideration for how social networks are associated with sse. the objective of this study was to identify personal and social network characteristics associated with being a recipient of sse. in this cross-sectional study, idus who injected in the past months were recruited from syringe exchange programs in montreal, canada, between april and january . information on each participant and on the persons with whom contact had occurred in the past month were elicited using a structured, interviewer-administe red questionnaire. participants provided detailed demographic and drug use information on up to idu members with whom drugs or injecting materials were shared. using logistic regression, personal and network characteristics were examined in relation to receipt of sterile syringes. res.its: of idus, % reported receiving sterile syringes in the past month from another idu. the sample mean age was years (range - ), % male, % caucasian, and % cocaine injectors. in multivariate analyses adjusted for age and gender, recipients of sterile syringes were more likely than non-recipients to share drugs after preparation ( r= . ( . - . )), to require help or to have helped inject another idu (or= . ( . - . )), to have asked someone to get sterile syringes from a syringe exchange program (or= . [ . - . )), to lend syringes (or= . [ . - . ) ) and to use drug preparation water that was previously used by another iou ( r= . ( . - . ) ) during the past months. recipients also had a higher rate of change (p= . ) of idus in their drug injecting network during the past month. with respect to social networks, % ( / ) of idu network members were providers of sterile syringes and were more likely than non-providers to inject everyday (or= . ( . - . )). when stratified by their role as a sexual partner or as someone who provides support (e.g. friend, family member), further risk behaviours were observed in relation to sharing injecting materials with the participant. conclusion: recipients of sterile syringes and their idu network members had several high-risk behaviours for infection with bloodborne diseases. sse may afford an opportunity for the dissemination of other salutary behaviours such as information sharing on safe injecting practices between recipients and distributors. furthermore, drug injecting networks may be an avenue to reach idus who may not otherwise be exposed to preventive measures. there are numerous sources of stigma and labelling of mental and physical illness. first, the sociocultural dimension to stigma and labelling clearly influences patients, families, health care professionals and society's perception and treatment of illness. this creates multiple challenges related to illness identification and recovery, particularly in culturally diverse societies. second, the media is a major source of stigma and stereotyping with regard to a variety of mental and physical illnesses. despite increased public knowledge of many illnesses, studies have shown that stigma has intensified over the years in certain cases. a third element of stigma and labels appears with the use of diagnosis as a solution to human problems with the result that difficult to treat patients are repudiated and social issues are unaddressed. this presentation will serve to outline the development of stigma, various expressions of stigma, and consequences of stigma. it will provide some practical recommendations for the reduction of stigma related to mental and physical illness. purpose: to assess the knowledge, attitude, and practice about immunization for parent of - years old hispanic and african american children in los angeles county (lac). methods: we conducted two cluster surveys in lac. the sample was selected with probability proportionate to estimated size at the first stage and simple random sample of children at the second stage. data were collected through interview. we absuacted vaccine coverage data from immunization record card (irc) at home or from clinic records. the participation was % in hispanics and % in african americans populations. irc was not available at home for % of african american and % of hispanic children. results: all parents perceived their children got all necessary vaccine~. fa~orable attitudes to.w~rd immunization were reported by % of african american and % of h s?amc parents. '.he m~ ority of the parents ( % african american and % hispanic) agreed that vaccines prevent senous d se~ses among children. regarding vaccine safety, significantly more hispanic parents ( %) than african american parents ( %) mentioned that vaccines are safe. introduction: cervical cancer has been shown to be preventable by papanicolau tests in heterosexual women; however, the utility of papanicolau test in lesbians is controversial. cervical cancer is caused by the human papillomavirus (hpv) which is transmitted by sexual _intercourse; howev_er, its' transmission by homosexual intercourse is also controversial. the goal of this study was to review the evidence for papanicolau tests in lesbians. methods: a pub med, ovid ( ovid ( to , and cochrane library search was performed using the mesh headings "homosexuality , female," "vaginal smears," and "papillomavirus, human." in pub med, the clinical queries feature was used with "diagnosis" and "broad, sensitive" filters. a google advanced search of the internet was conducted with the terms "lesbian," "cervical cancer," and "pap rest." the url was limited to ".ca," ".edu," or ".gov." results: the search yielded original articles and reviews, but no cochrane reviews. none of the publications were canadian. website hits were found and selected websites were reviewed. studies showed that lesbians have fewer papanicolau tests than heterosexual women; however, many reported risk factors for cervical cancer, including multiple past or current sexual partners (male and female), early age of first coitus, history of sexually transmitted diseases, and cigarette smoking. hpv has been detected in - % of lesbians and - % of lesbians who have never had sex with men. case studies of abnormal papanicolau tests in lesbians who have never had sex with men have also been reponed. sexual transmission of hpv among lesbians can be explained by several factors: ) - % of lesbians have had sex with men and - % of lesbians continue to have sex with men. ) hpv may be transmitted by sexual behaviours among women, like digital-vaginal sex, digital-anal sex, oral sex, and the use of insertive sex toys. ) hpv transmission requires only skin-to-skin contact. genital hpv has been identified on human fingers. some professional organizations, like the society of obstetricians and gynecologists of canada and the american cancer society, recognize the need for papanicolau tests in lesbians. other organizations, like the canadian cancer society, do not have official policy statements. the current ontario cervical screening program does not specifically address lesbians. conclusion: although the data was limited, most studies recommended that lesbians should receive papanicolau tests. the frequency of these tests was controversial. policy makers and professional organizations should address the needs of this special population and make specific recommendations . monique chaaya, ahia sibai, hiam chemaitelly, and zana el roueiheb . literature concerning the mental and physical effect of work at an old age is contradictory. in addinon, urban environments are physically and socially harsh with reduced potential for income generation and employment and increased potential for depression. the present paper is an attempt to study how do work, or lack of work, link to the experience of depression among older adults in underprivileged lebanese urban communities. the data comes from a cross-sectional survey, where elderly residing in underprivileged communities in beirut, including a palestinian refugee camp, were successfully inter-v ewed through face-to-face interviews. logistic regression was performed to assess the effect of work on depression ad_justing for many other covariates. data showed that . % of people aged years and more were still workmg. there was a highly protective effect of work on depression in elderly males (or= . , % cl= . - . ). the current study is the first of its kind in the arab region and more work shou_ld be _don_e in this area. it is important for the lebanese government to consider elderly rights for social mclus n m terms of employment opportunities. amam nuru-jeter, nancy adler, and burton singer . l~u~on:_ the socioeconomic gradient is perhaps the most persistent and significant finding in social epidem ological research. the insistent nature of the ses effect is evidenced by its significance after acc?untmg for ~umerous confounds. the significance and magnitude of the effect, however, varies by ::•al group. evidence_ o_f the relative effect of race and ses is inconclusive. further, less attention has f ~ ptid to the specific interactions of race and ses than to examinations of which is a better predictor d ~ th. ~sues are further complicated by the explanatory complexity of the various measures of ses anl . owht ey relate to the health of various social groups. understanding the specific nature of these re a ons ips s necessary for guiding he ith d · i · · h a an soc a po mes and programs aimed at improving t e poster sessions v health of our most disadvantaged groups, and therefore population health, overall. this study examines the synergistic effects of ses with both race and gender in predicting group differences in mortality. methods: analyses use data from the national longitudinal mortality survey (n= , ) for the years , , and - ; and were linked to the national death index for deaths occurring through . results were confirmed using data from the national mortality followback survey for people who died in (n= , ) and the national health interview survey (denominator). we used correlation analysis and the standardized mortality ratio to examine ses (education and income), race, and gender as predictors of group differences in changes in mortality. results: for the total population, analyses support the income gradient showing significant declines in mortality ratios from low to high income along the income strata. education shows a significant drop in mortality with completion of high school and completion of college, exhibiting a threshold rather than a gradient effect. compared to whites, blacks receive diminishing health returns for each subsequent level of income and education; with whites closely mirroring the total population in ses thresholds. similarly, compared to men, women do not experience the same health gains at comparable ses levels. for education, black men and women only show significant mortality declines upon completion of high school. the ses gradient operates differently among race and gender subgroups. threshold effects suggest resource gains in life opportunities at particular milestones along the ses gradient. further, ses matters less for blacks and women compared to whites and men suggesting differing implications for health and social policy aimed at reducing disparities. objective: we assessed the impact of diabetes in a large puerto rican community of chicago by measuring the prevalence of diagnosed diabetes and calculating the diabetes mortality rate. methods: we analyzed data from a comprehensive health survey conducted in randomly selected households in community areas. questions on diagnosed diabetes and selected risk factors were asked. in addition, mortality data were analyzed in order to calculate the age-adjusted diabetes mortality rate. when possible, rates were compared to those found in other studies. results: the diabetes prevalence located in this community ( . %: % cl= . %- . %) is one of the highest ever reported for puerto ricans. for instance, it is more than three times higher than the prevalence for the us ( . %) and twice the prevalence for puerto ricans in new york ( . %) and puerto rico ( . %- . %). diagnosed diabetes was found to be significantly associated with obesity (p= . ). the prevalence was particularly high among older people, females, those horn in the us, and those with a family history. the diabetes mortality rate ( . per , population) was more than twice the rate for all of chicago ( . ) and the us ( . ). conclusions: understanding why the diabetes and mortality rates for puerto ricans in this commu· nity are so much higher than those of other communities is imperative. collaboration between researchers, service providers and community members can help address the issues of diabetes education, early screening and diagnosis and effective treatment needed in this community. introduction: sars is a respiratory illness that is spread from person to person through dose contact. this infectious disease outbreak was unusual due to the high rate of infection among health care workers. the aim of the study is to explore the demographic and attitudinal determinants of psychological distress due to sars among health care workers of a toronto hospital. methods: a total of adult participants completed questionnaires co assess psychological distress (impact of event scale -jes) and attitudes to sars. of these, participants completed the questionnaire during the sars i outbreak, and participants completed the questionnaire during the sars ii outbreak. participants also provided information on demographic variables, including occupation and exposure to sars. principal components analysis was used to derive eight attitudinal scales: fear: system, protection, prevention, job stress, stigma, instrumental coping, and psychological copm~. l ear regression analyses were applied to evaluate the associations of the demographic and amtudmal variables, as well as time, with psychological distress. . . regression analyses showed that time and higher scores on fear, ob stress, stigma'. and instrumental coping were associated with a higher total ies score: (r =. ). contrary to expectations, none of the demographic variables was associated with total ies score. conclusion: the presence of psychological distress in health care workers is indicative of intrusive or avoidant responses to thoughts, feelings, and memories associated with the sars outbreak. this study shows that ( ) fear for one's health and the he~lth of.others, ( ) ex~erien~in~ job stress, ( )_tbe per· ception of stigma, ( ) usage of instrumental copmg skills, ~n~ ( ) t m_e s grufi~an~ly c~nmb~te to increased psychological distress in health care workers. potential mterventmns during mfecttous diseaie outbreaks in health care settings should be targeted to minimize the impact of these factors. purpose: the purpose of this study was to expand knowledge regarding feeding practices, know!· edge and nutritional beliefs of mothers currently residing in the dominican republic (dr). the rising incidence of obesity in children is a major national health concern and obesity in first and second-generation immigrant children also continues to rise. we know that parents (particularly mothers) shape children's early diet patterns and that immigrant mothers experience additional challenges related to acculturation and assimilation into a new culture, however there is a paucity of literature concerning the effect of immigrant adaptation to american culture on the nutrition of children. in addition, new immigrant knowledge about the causes of obesity and the resulting health implications for childhood obesity has not been assessed and reported. this qualitative study used focus group methodology to discuss views and practices related to the introduction of food for infants and feeding practices for young children, along with a discussion on knowledge and beliefs related to the causes and health implications of child· hood obesity. ten dominican mothers' of young children (birth to years old) who reside in a small town in the western frontier area of the dr were participants in the focus group. results from this srudy will be compared to results from an identical study that will be conducted in fall with new immi· grant mothers from the dr to the boston area. we will compare feeding practices, beliefs and knowledge about nutrition for young children between these two groups. methods: using participatory principles, a focus group design was used to interview a group of mothers in the dr. the investigator along with a bilingual translator conducted the focus group. the session was tape recorded and is currently in the process of being transcribed and translated. transcribed data will be systematically analyzed themes will be identified. a qualitative data analysis software will be used to organize and code the data according to the specific aims of the study. supporting quotations will be selected to substrate each theme. lmpli~tions for urban health practice: an ultimate goal of this study is to lay a foundation for understanding the process of acculturation on feeding practices of mothers when they immigrate to the us. understanding beliefs, knowledge and feeding practices that mothers use with young children will help m ~he ~evelopment of culturally and linguistically appropriate educational strategies and materials for use m primary prevention of pediatric obesity. in canada more than seventy-five percent of immigrants choose to stay in three major urban centers of toronto, montreal and vancouver. approximately fifty percent of the immigrants eventually set· tie m ~~e greater tor<_>nto area. there is mounting evidence that the increasing immigrant population has a_ sigmfic~nt health disadvantage over canadian-born residents. this health disadvantage manifests particularly m the ma "ority of "mm "gr t h h d be · · h . . . . an s w o a en m canada for longer than ten years. this group as ~n associ~te~ with higher risk of chronic disease such as cardiovascular diseases. this disparity twccb n ma onty of the immigrant population and the canadian-born population is of great importance to ur an health providers d" · i i · b as isproporttonate y arge immigrant population has settled in the ma or ur an centers. generally the health stat f · · · · · · h h been . us most mm grants s dynamic. recent mm grants w o av_e ant •;ffca~ada _for less ~han ~en years are known to have a health advantage known as 'healthy imm • ~ants r::r · ~:s eff~ ~ defined by the observed superior health of both male and female recent immi- immigrant participation in canadian society particularly the labour market. a new explanation of the loss of 'healthy immigrant effect' is given with the help of additional factors. lt appears that the effects of social exclusion from the labour market leading to social inequalities first experienced by recent immigrant has been responsible for the loss of healthy immigrant effect. this loss results in the subsequent health disadvantage observed in the older immigrant population. a study on patients perspectives regarding tuberculosis treatment by s.j.chander, community health cell, bangalore, india. introduction: the national tuberculosis control programme was in place over three decades; still tuberculosis control remains a challenge unmet. every day about people die of tuberculosis in india. tuberculosis affects the poor more and the poor seek help from more than one place due to various reasons. this adversely affects the treatment outcome and the patient's pocket. many tuberculosis patients become non-adherence to treatment due to many reasons. the goal of the study was to understand the patient's perspective regarding tuberculois treatment provided by the bangalore city corporation. (bmc) under the rntcp (revised national tuberculosis control programme) using dots (directly observed treatment, short course) approach. bmc were identified. the information was collected using an in-depth interview technique. they were both male and female aged between - years suffering from pulmonary and extra pulmonary tuberculosis. all patients were from the poor socio economic background. results: most patients who first sought help from private practitioners were not diagnosed and treated correctly. they sought help form them as they were easily accessible and available but they. most patients sought help later than four weeks as they lacked awareness. a few of patients sought help from traditional healers and magicians, as it did not help they turned to allopathic practitioners. the patients interviewed were inadequately informed about various aspect of the disease due to fear of stigma. the patient's family members were generally supportive during the treatment period there was no report of negative attitude of neighbours who were aware of tuberculosis patients instead sympathetic attitude was reported. there exists many myth and misconception associated with marriage and sexual relationship while one suffers from tuberculosis. patients who visited referral hospitals reported that money was demanded for providing services. most patients had to borrow money for treatment. patients want health centres to be clean and be opened on time. they don't like the staff shouting at them to cover their mouth while coughing. conclusion: community education would lead to seek help early and to take preventive measures. adequate patient education would remove all myth and conception and help the patients adhere to treatment. since tb thrives among the poor, poverty eradiation measures need to be given more emphasis. mere treatment approach would not help control tuberculosis. lntrod#ction: the main causative factor in cervical cancer is the presence of oncogenic human papillomavitus (hpv). several factors have been identified in the acquisition of hpv infection and cervical cancer and include early coitarche, large number of lifetime sexual partners, tobacco smoking, poor diet, and concomitant sexually transmitted diseases. it is known that street youth are at much higher risk for these factors and are therefore at higher risk of acquiring hpv infection and cervical cancer. thus, we endeavoured to determine the prevalence of oncogenic hpv infection, and pap test abnormalities, in street youth. ~tbods: this quantitative study uses data collected from a non governmental, not for profit dropin centre for street youth in canada. over one hundred females between the ages of sixteen and twentyfour were enrolled in the study. of these females, all underwent pap testing about those with a previous history of an abnormal pap test, or an abnormal-appearing cervix on clinical examination, underwent hpv-deoxyribonucleic (dna) testing with the digene hybrid capture ii. results: data analysis is underway. the following results will be presented: ) number of positive hpv-dna results, ) pap test results in this group, ) recommended follow-up. . the results of this study will provide information about the prevalence of oncogemc hpv-dna infection and pap test abnormalities in a population of street youth. the practice implic~ tions related to our research include the potential for improved gynecologic care of street youth. in addition, our recommendations on the usefulness of hpv testing in this population will be addressed. methods: a health promotion and disease prevention tool was developed over a period of several years to meet the health needs of recent immigrants and refugees seen at access alliance multicultural community health centre (aamchc), an inner city community health centre in downtown toronto. this instrument was derived from the anecdotal experience of health care providers, a review of medical literature, and con· sultations with experts in migration health. herein we present the individual components of this instrument, aimed at promoting health and preventing disease in new immigrants and refugees to toronto. results: the health promotion and disease prevention tool for immigrants focuses on three primary health related areas: ) globally important infectious diseases including tuberculosis (tb), hiv/aids, syphilis, viral hepatitis, intestinal parasites, and vaccine preventable diseases (vpd), ) cancers caused by infectious diseases or those endemic to developing regions of the world, and ) mental illnesses includiog those developing among survivors of torture. the health needs of new immigrants and refugees are complex, heterogeneous, and ohen reflect conditions found in the immigrant's country of origin. ideally, the management of all new immigrants should be adapted to their experiences prior to migration, however the scale and complexity of this strategy prohibits its general use by healthcare providers in industrialized countries. an immigrant specific disease prevention instrument could help quickly identify and potentially prevent the spread of dangerous infectious diseases, detect cancers at earlier stages of development, and inform health care providers and decision makers about the most effective and efficient strategies to prevent serious illness in new immigrants and refugees. lntrodmction: as poverty continues to grip pakistan, the number of urban street children grows and has now reached alarming proportions, demanding far greater action than presently offered. urbanization, natural catastrophe, drought, disease, war and internal conflict, economic breakdown causing unemployment, and homelessness have forced families and children in search of a "better life," often putting children at risk of abuse and exploitation. objectives: to reduce drug use on the streets in particular injectable drug use and to prevent the transmission of stds/hiv/aids among vulnerable youth. methodology: baseline study and situation assessment of health problems particularly hiv and stds among street children of quetta, pakistan. the program launched a peer education program, including: awareness o_f self and body protection focusing on child sexual abuse, stds/hiv/aids , life skills, gender and sexual rights awareness, preventive health measures, and care at work. it also opened care and counseling center for these working and street children ar.d handed these centers over to local communities. relationships among aids-related knowledge and bt:liefs and sexual behavior of young adults were determined. rea.sons for unsafe sex included: misconception about disease etiology, conflicting cultural values, risk demal, partner pressur~, trust and partner significance, accusation of promiscuity, lack of community endorsement of protecnve measures, and barriers to condom access. in addition socio-economic pressure, physiological issues, poor community participation and anitudes and low ~ducation level limited the effectiveness of existing aids prevention education. according to 'the baseline study the male children are ex~ to ~owledge of safe sex through peers, hakims, and blue films. working children found sexual mfor~anon through older children and their teachers (ustad). recommendation s: it was found that working children are highly vulnerable to stds/hiv/aids, as they lack protective meas":res in sexual abuse and are unaware of safe sexual practices. conclusion: non-fatal overdose was a common occurrence for idu in vancouver, and was associated with several factors considered including crystal methamphetamine use. these findings indicate a need for structural interventions that seek to modify the social and contextual risks for overdose, increased access to treatment programs, and trials of novel interventions such as take-home naloxone programs. background: injection drug users (idus) are at elevated risk for involvement in the criminal justice system due to possession of illicit drugs and participation in drug sales or markets. the criminalization of drug use may produce significant social, economic and health consequences for urban poor drug users. injection-related risks have also been associated with criminal justice involvement or risk of such involvement. previous research has identified racial differences in drug-related arrests and incarceration in the general population. we assess whether criminal justice system involvement differs by race/ethnicity among a community sample of idus. we analyzed data collected from idus (n = , ) who were recruited in san francisco, and interviewed and tested for hiv. criminal justice system involvement was measured by arrest, incarceration, drug felony, and loss/denial of social services associated with the possession of a drug felony. multivariate analyses compared measures of criminal justice involvement and race/ethnicity after adjusting for socio-demographic and drug-use behaviors including drug preference, years of injection drug use, injection frequency, age, housing status, and gender. the six-month prevalence of arrest was highest for whites ( %), compared to african americans ( %) and latinos ( % ), in addition to the mean number of weeks spent in jail in the past months ( . vs. . and . weeks). these differences did not remain statistically significant in multivariate analyses. latinos reported the highest prevalence of a lifetime drug felony conviction ( %) and mean years of lifetime incarceration in prison ( . years), compared to african americans ( %, . years) and whites ( %, . years). being african american was independently associated with having a felony conviction and years of incarceration in prison as compared to whites. the history of involvement in the criminal justice system is widespread in this sample. when looking at racial/ethnic differences over a lifetime including total years of incarceration and drug felony conviction, the involvement of african americans in the criminal justice system is higher as compared to whites. more rigorous examination of these data and others on how criminal justice involvement varies by race, as well as the implications for the health and well-being of idus, is warranted. homelessness is a major social concern that has great im~act on th~se living.in urban commu?ities. metro manila, the capital of the philippines is a highly urbanized ar~ w. t~ the h gh~st concentration of urban poor population-an estimated , families or , , md v duals. this exploratory study v is the first definitive study done in manila that explores the needs and concerns of street dwdlent\omc. less. it aims to establish the demographic profile, lifestyle patterns and needs of the streetdwdlersindit six districts city of manila to establish a database for planning health and other related interventions. based on protocol-guid ed field interviews of street dwellers, the data is useful as a template for ref!!. ence in analyzing urban homelessness in asian developing country contexts. results of the study show that generally, the state of homelessness reflects a feeling of discontent, disenfranchisem ent and pow!!· lessness that contribute to their difficulty in getting out of the streets. the perceived problems andlar dangers in living on the streets are generally associated with their exposure to extreme weather condirioll! and their status of being vagrants making them prone to harassment by the police. the health needs of the street dweller respondents established in this study indicate that the existing health related servias for the homeless poor is ineffective. the street dweller respondents have little or no access to social and health services, if any. some respondents claimed that although they were able to get service from heallh centers or government hospitals, the medicines required for treatment are not usually free and are beyond their means. this group of homeless people needs well-planned interventions to hdp them improve their current situations and support their daily living. the expressed social needs of the sucet dweller respondents were significantly concentrated on the economic aspect, which is, having a perma· nent source of income to afford food, shelter, clothing and education. these reflect the street dweller' s need for personal upliftment and safety. in short, most of their expressed need is a combination of socioeconomic resources that would provide long-term options that are better than the choice of living on the streets. the suggested interventions based on the findings will be discussed. . methods: idu~ aged i and older who injected drugs within the prior month were recruited in usmg rds which relies on referral networks to generate unbiased prevalence estimates. a diverse and mon· vated g~o~p of idu "seeds." were given three uniquely coded coupons and encouraged to refer up to three other ehgibl~ idu~, for which they received $ usd per recruit. all subjects provided informed consent, an anonymous ~t erv ew and a venous blood sample for serologic testing of hiv, hcv and syphilis anti~!· results. a total of idus were recruited in tijuana and in juarez, of whom the maion!)' were .male < .l. % and . %) and median age was . melhotls: using the data from a multi-site survey on health and well being of a random sample of older chinese in seven canadian cities, this paper examined the effects of size of the chinese community and the health status of the aging chinese. the sample (n= , ) consisted of aging chinese aged years and older. physical and mental status of the participants was measured by a chinese version medical outcome study short form sf- . one-way analysis of variance and post-hoc scheffe test were used to test the differences in health status between the participants residing in cities representing three different sizes of the chinese community. regression analysis was also used to examine the contribution of size of the chinese community to physical and mental health status. rmdts: in general, aging chinese who resided in cities with a smaller chinese population were healthier than those who resided in cities with a larger chinese population. the size of the chinese community was significant in predicting both physical and mental health status of the participants. the findings also indicated the potential underlying effects of the variations in country of origin, access barriers, and socio-economic status of the aging chinese in communities with different chinese population size. the study concluded that size of an ethnic community affected the health status of the aging population from the same ethnic community. the intra-group diversity within the aging chinese identified in this study helped to demonstrate the different socio-cultural and structural challenges facing the aging population in different urban settings. urban health and demographic surveillance system, which is implemented by the african population & health research center (aphrc) in two slum settlements of nairobi city. this study focuses on common child illnesses including diarrhea, fever, cough, common cold and malaria, as well as on curative health care service utilization. measures of ses were created using information collected at the household level. other variables of interest included are maternal demographic and cultural factors, and child characteristics. statistical methods appropriate for clustered data were used to identify correlates of child morbidity. preliminary ratdts: morbidity was reported for , ( . %) out of , children accounting for a total of , illness episodes. cough, diarrhoea, runny nose/common cold, abdominal pains, malaria and fever made up the top six forms of morbidity. the only factors that had a significant associ· ation with morbidity were the child's age, ethnicity and type of toilet facility. however, all measures of socioeconomic status (mother's education, socioeconomic status, and mother's work status) had a significant effect on seeking outside care. age of child, severity of illness, type of illness and survival of father and mother were also significantly associated with seeking health care outside home. the results of this study have highlighted the need to address environmental conditions, basic amenities, and livelihood circumstances to improve child health in poor communities. the fact that socioeconomic indicators did not have a significant effect on prevalence of morbidity but were significant for health seeking behavior, indicate that while economic resources may have limited effect in preventing child illnesses when children are living in poor environmental conditions, being enlightened and having greater economic resources would mitigate the impact of the poor environmental conditions and reduce child mortality through better treatment of sick children. inequality in human life chances is about the most visible character of the third world urban space. f.conomic variability and social efficiency have often been fingered to justify such inequalities. within this separation households exist that share similar characteristics and are found to inhabit a given spatial unit of the 'city. the residential geography of cities in the third world is thus characterized by native areas whose core is made up of deteriorated slum property, poor living conditions and a decayed environment; features which personify deprivation in its unimaginable ma~t~de. there are .eviden~es that these conditions are manifested through disturbingly high levels of morbidity and mortality. ban · h h d-and a host of other factors (corrupt n, msens t ve leaders p, poor ur ty on t e one an , . · f · · · th t ) that suggest cracks in the levels and adherence to the prmc p es o socta usnce. ese governance, e c . . . . . ps £factors combine to reinforce the impacts of depnvat n and perpetuate these unpacts. by den· grou o . · "id . . bothh tifying health problems that are caused or driven by either matena _or soc a e~nvanon or , t e paper concludes that deprivation need not be accepted as a way. of hfe a~d a deliberate effon must be made to stem the tide of the on going levels of abject poverty m the third world. to the extent that income related poverty is about the most important of all ramifications of po~erty, efforts n_iu_st include fiscal empowerment of the poor in deprived areas like the inner c~ty. this will ~p~ove ~he willingness of such people to use facilities of care because they are able to effectively demand t, smce m real sense there is no such thing as free medical services. ). there were men with hiv-infection included in the present study (mean age and education of . (sd= . ) and . (sd= . ), respectively). a series of multiple regressions were used to examine the unique contributions of symptom burden (depression, cognitive, pain, fatigue), neuropsychologic al impairment (psychomotor efficiency), demographics (age and education) and hiv disease (cdc- staging) on iirs total score and jirs subscores: ( ) activities of daily living (work, recreation, diet, health, finances); ( ) psychosocial functioning (e.g., self-expression, community involvement); and ( ) intimacy (sex life and relationship with partner). resnlts: total iirs score (r " . ) was associated with aids diagnosis (ii= . , p < . ) and symptoms of pain (ii= - . , p < . ), fatigue (ji = - . , p < . ) and cognitive difficulties (p = . , p < . ). for the three dimensions of the iirs, multiple regression results revealed: ( ) activities of daily living (r = . ) were associated with aids diagnosis (ii = . , p < . ) and symptoms of pain <p =- j , p < . ), fatigue (ji = - . , p < . ) and cognitive difficulties (ji = . , p < . ); ( ) psychosocial functioning (r = . ) was associated with was associated with symptoms of fatigue (ii= - . , p < . ) and cognitive difficulties <ii = . , p < . ); and ( ) intimacy (r = . ) was related to was associated with symptoms of fatigue (ij = - . , p < . ) and cognitive difficulties (ii= . , p < . ). methods: the sif evaluation methodology involves a comprehensive database located at the sif, a randomly selected p~o.spective coh~rt of sif users, and two pre-existing external control cohorts. . . ~ts: in addmon to reporting process data and descriptions of the sif users, we report on data indicating that the establishment of the sif has been independently associated with reductions in public ~':°g ~ (p <?. ), and syringe sharing (aor = . [ %ci: . _ . ); p = . ) and other unsafe m ecnon pract _ces_ (p ~ . ), and increased uptake of detox services (log-rank p = . ). as well, we report on da~ md cat ng that the sif has not prompted adverse changes in community drug use patterns. the vancouver sif has been well accepted by the target population, and while adve~ events s~c~ as overdoses have occurred, these events have been successfully managed. externally compiled data indicate that the sif has been associated with substantial declines in public disorder !'oster sessions v associated with injection drug use, syringe sharing, and increased uptake of detox services. as well, the establishment of the sif has not exacerbated community drug use patterns. ongoing evaluation activities wiu involve assessing the impact of the sif on a variety of outcomes, including infectious disease transmission, fatal overdose, and utilization of health and social services. city, brazil, - maria cristina almeida, waleska caiaffa, renato assum;iio, and fernando proietti dengue cases were described according to time, space, intensity, age, gender, onset of symptoms, residence address and census tract. spatial distribution of two groups (children and women over years old and men aged - ) were compared, under assumption that they have distinct behaviors regarding their displacement around the city. analysis included local moran index, ripley\\'s k function and recurrence of census areas over time. about , cases were identified in seven epidemic waves. concentration of cases in small areas, followed by a spread either in space or time suggested endemic patterns. regarding age-gender groups, distinct patterns suggested that residence might not be a good proxy in determining the local of infection for men aged - . dengue is shifting to endemic pattern in this city and transmission may not be sole related to home environment, suggesting that additional spatial information must be couected aiming efficient control measures. murukan kandamuthan and subodh kandamuthan lnl uduction: illness or disablement of a child may affect the economic functioning of a family as it alters the employment pattern and earnings of parents this paper tries to assess the health status and the quality of life of disabled children, and how generally, severe disablement in a child affected their fami-lies\' finances, and to quantify any such effects the problems faced by children in their home and to provide information relevant to the formation of criteria for new or increased cash support. methods: a case-control study was done in the thiruvananthapuram district, capital city of kerala by selecting a random sample of families with severely disabled children below years and a random sample of normal children matched for age and occupation of the parents. comparative and subjective data were collected. money spent on children\'s medical care, loss of earnings of the parents, and other economic burden to the family due to the disability of the child in the family. a discriminant analysis along with univariate analysis was done to assess the factors that mostly differentiate the disabled and normal children. the mean expenditure of the families with a disabled child was rs. /-per month, which is significantly higher than the corresponding expenditure of rs. /-per month of families with normal child, (t= . , p <. ). of the disabled children, % were not getting any social security payments and % had no special concessions for medical and other educational purposes. the analysis of income and expenditure pattern indicated that financial impact of disablement in a child on the family is significant. the discriminant model results revealed that medical expenditure was a significant variable that differentiated the disabled and normal child. the study found that the health status and quality of life of the disabled children were far from satisfactory. this in fact affected the economic status of the disabled children. in addition to reduced earnings, there are extra costs for disabled children for travel, domestic help, medical care, and health care expenditures (hospital care, physician services, dentistry, drugs and others) for disabled individuals. a strong case can be made for their long-term care by improving the financial support to such families possibly through the introduction of an allowance specially to compensate for the earnings lost by parents due to the disability of their children. widows in india are considered disadvantage group of population. because they are characterized by pangs of separation from spouse, and consequently they go through mental agony, social ~s?lation, and economic dislocation. in addition to these, poverty, landlessness, homelessness, malnutr non etc. endure serious deterioration of their health. according to census , there are million women are widowed and one fourth live in urban areas. there is a noticeable increase of urban widows from the previous census (almost half). the paper examines the type of disability and chronic ailment borne among elderly widows ( years and above). fifty second round of national sample survey aske~ the individuals three sets of questions regarding their health: their status of health, whether they are physically poster sessions v immobile, and whether or not they have had any specific chronic illnesses. although health infrastruc- · ble ·n urban setting in india as compared to rural counterpart, prevalence of tures are arge y ava a . . . . . h · · · h h"gher "n urban areas analysis shows omt problems m old age qmte common c romc ness is muc • . . and nearly percent elderly widows are suffering from this ail'. ent in urban areas. one-fifth of widows are suffering from high/low bp. heart disease, diabetes and urinary problems are much ~ore pre~alent in urban areas though disabilities is comparatively lower in urban areas. however, the d~fference is not statistically significant. disability with respect to vision is more pronounced and one third_ of the total respondents have problems regarding eyesight. one fifths ofdderly widows are _ha.rd of hearing. though disability increases with age, similar trend is not observed with respect to chr~mc illness. the percepnon of self-health among elderly becomes poorer as their age increases. the perceived health status need not be always corrected to objective indicators of health. it is noted that around per~en~ of those perceived their health as "excellenr" or "very good" are found to be suffering from chrome disease of omts and percent have visual disability. to conclude an elderly widow living in urban areas have similar health problems as she jives in rural areas. this can be easily explained, as they were not made aware to seek treatment from health facility. in addition, the study shows that the economic conditions are deterrent factors for their illness. it is essential that intervention should be taken up improving their economic conditions so that wellbeing of this most vulnerable group of the society can be taken care of. heart failure is a disease that affects nearly million people world wide. the united states alone accounts for one third of this population. blacks are stricken with heart failure twice as often as whites. men are more likely to develop chf than women, however since the majority of the chf population are seniors, there are actually more women than men. congestive heart failure (chf) has become a pandemic. as the baby boomer generation ages, the number of chf cases will rise dramatically. (young, j. & mills, r., ). after the age of , each proceeding decade doubles the incidence level of chf. the average person has a in chance of developing heart failure within their lifespan according to the framingham study (nih.gov). individuals aging or older compose over half of the entire documented heart failure population. in this age group, chf is the leading cause of hospitalization. many patients are continuously readmitted. it is estimated that the chf population will increase by one million within the next years. mortality was at % for a two year period and % for five years (young, j. & mills, r., ). data from: aha as technology evolves, the understanding of the nature of heart failure has become clearer. in the beginning of the th century heart failure was diagnosed as a condition that presented with edema (swelling) in the extremities caused by water retention. treatment in the beginning of the past cenrury was limited to abdominal drainage and diuretics. the discovery of the heart's insufficient pumping ability in heart failure patients lead to new surgeries and devices such as heart transplants and ventricular assist devices (bridge until transplant is available). ventricular hypertrophy often occurs before the development of heart failure. hypertrophy is the term given for cardiac remodeling. cardiac remodeling also includes chamber dilation (young, j. & mills, r., ) . chf financial burden the us healthcare financing administration has ranked chf as the highest cost illness in the diagnose-related area. direct costs related to chf in the us for were nearly $ billion. these costs included hospital admissions, physician fees, home health aids and medications. indirect costs were over $ billion in . loss of jobs or death due to chf was the criteria for this category (young, j. & mills, r., ). . introduction: the injection drug user quality of life scale (iduqol) is a relatively new scale ~es gned to capture the unique and individual circumstances that determine quality of life among injection drug users (idus). the life areas comprising the instrument were based on the research literature an~ ~ocus group discussions with idus. the purpose of the present study was to evaluate the content validity of t.h~ iduqol using judgmental methods based on subject matter experts' (smes) ratings. content vah~ ty refers to the de~ee to which elements of an assessment tool are representative of the construct of interest and appropnate for a given population. methods: data were obtained from six smes, from the field of idu research and practice, who ~ere. asked t.o evaluate various aspects of the iduqol, including the title of the instrument, administraon instruchons, clarity of the names and descriptions of each life area, response format, scoring instruc-no~s and examples, record form and whether each life area should be included in the instrument. sme ratings were made using either or point scales. sm es were also given the opportunity to comment on poster sessions v each section and to suggest whether important life areas had been overlooked, were redundant, not relevant, or in need of revision. (cvi) and the ~v.erage ~eviation index (ad) were used to evaluate smes' agreement on ratings of the content vahd ty vanables. both measures provided support for the content validity of various aspects of the iduqol, although results from the stricter ad index noted some areas of disagreement, including the description of particular life areas (e.g., being useful, drugs, sex), the inclusion of some life areas (e.g., drug treatment, education, independence and free choice), and the ease of the scoring instructions. the findings from this study provide (a) content validity evidence to support the use of the iduqol as well as (b) recommendations to suengthen both the instrument (e.g., improved descriptions for some items) and the accompanying administration and scoring manual (e.g., an easier scoring template). changes made to the instrument and its manual make the iduqol even easier for researchers, practitioners, and program evaluators to use as a way of assessing, and tracking changes over time or as a result of interventions in, quality of life in injection drug users. introduction: strict adherence to prescribed regimens is required to derive maximal benefit from highly active antireuoviral therapy (haart) in persons living with hiv/aids (phas). adherence is a key determinant of the degree and durability of viral suppression. adherence is also essential in reducing the spread of hiv and ensuring that today's treatments remain effective for as long as possible. the objective of this study is to conduct a systematic review of the research literature on the effectiveness of education and patient support strategies for improving adherence to haart. methods: a systematic search of the core databases was performed from january until may . randomized controlled trials examining the effectiveness of education and patient support interventions to improve the adherence to haart were considered for inclusion. only those studies that measured adherence at a minimum of six weeks were included. study selection, quality assessments, and data abstraction were performed independently by two reviewers. results: study heterogeneity with respect to differing populations, interventions, outcomes, and length of follow-up did not allow for meta-analysis. we included studies involving , ph as. sample sizes ranged from to . study duration ranged from a single session to a variable number of sessions delivered over one year. many of the interventions involved the provision of an educational component to improve adherence and often addressed strategies to overcome barriers to adherence and the development of problem-solving skills. they ranged from simple interventions (e.g., the provision of reminder devices) to complex interventions (e.g., cognitive-behavioural therapy delivered by licensed psychologists). eleven of the studies demonstrated a statistically significant advantage associated with the described adherence intervention. the advantage associated with adherence outcomes does not seem to translate into the more clinically relevant outcome of viral suppression. only out of studies that reported virological or immunological results found a significant effect associated with the intervention. the studies had several methodological shortcomings. conclusions: there is a need for standardization and methodological rigour in the conduct of adherence trials. some interventions may have a significant impact on improving adherence. further research is required before any specific adherence improving strategy can confidently be incorporated into standard clinical practice. focus groups were used to collect data from a purposive sample of treatmentexperienced participants. focus group data were analyzed using a grou~ded t~eory appr~ach. i:ne themes identified from the interviews were used to identify the effects of ant rerrov rals on quality of hfe. the content of the mos-hiv was appraised against the themes identified from our analysis. participants also completed the mos-hiv survey and were asked whether the survey covered all important aspects of quality of life on antiretroviral medications. results: five key informant interviews and five focus groups with participants were used to identify effects on quality of life that are not directly ~aptu~ed by_ the mos-hiv health survey. our~~ showed that our participants described quality of hfe as mvol~mg_ a set of ~rsonal trad~ffs ~stay alive. in most cases, worsened quality of life was traded-off for gams ~ longevlty from ~~canon use. these eff~'ts or tradeoffs included: ( ) downstream consequences of side effects and toxlanes; ( ) loss of lrufe. pende~t decision-making privileges, ( ) having to choose drugs over ~areer; (~)burden of medication-taking responsibilities; and ( ) living life under a pretense and havmg to hide-the net effect of the tradeoffs, or "prices" to pay led to what was described as "longevity with hn without hope and future~. conclusion: our study highlights five major themes summarizing the impact of haart on quality on life, and suggests that currently used scales for measuring quality of life do not a~atd~ cap~e these findings and the associated consequences. the conceptual framework for measuring quality of bfe in hiv should be reconsidered in order to better capture the important effects of the medications on quality of life. this may involve widening the boundaries of the definition of health-related quality oflife to include aspects such as finances, employment, and housing. we should further consider the development of a haart adverse effect specific instrument, using a broad definition of adverse effect in order to capture all types of adverse impacts of hiv treatments on quality of life. introduction: measles (rubeola) is the most contagious vaccine preventable disease of humans. while cases of measles are uncommon in canada today, the disease continues to be a leading cause of morbidity and death in the developing world. as a result of human migration, measles cases still occur in canada, primari~ among immigrants, returning travelers, and other susceptible groups. canada's national advisory council on immunizations (naci) recommends that immigrants without records of measles immunization be considered for vac:cination since these individuals may not have been appropriately vaccinated in their native country. on rhe other hand, natural immunity to measles in immigrants is likely to be high given the high incidence of disease in developing parts of rhe world. thus it remains unclear if the most efficient strategy to achieve high levels of measles immunity in immigrants should entail initial serologic screening followed by vaccination of susceptible individuals or preemptive vaccination of all persons lacking immunization records. understanding the epidemiology of measles immunity in immigrant populations could help guide such decisions. . methods: we identified adults, years of age or older, who were screened for serologtc immunity to measles as part of a recently developed screening protocol at a downtown toronto community health centre. we subsequently determined if these individuals had any immunization records from their native country or from within canada. we then examined the relationship between several demographic factors and immunity to measles. results: % of immigrants had no prior immunization records. overall, % of the immigrants rested for immunity to measles were found to be immune; % of those under the age of , % of those between and years of age, % of those between and years of age, and % of those years of age or older. gender, education status, household income, and immigration status were nor ~ssoc ated wirh immunity to measles. immunity to measles was lowest among immigrants from eastern europe ( ~%), whil~ immigrants from other regions of the globe had greater than % immunity. c~lusrons: immigrants and refugees appear to have reasonably high levels of immunity to mea· sics, possibly related to natural infection wirh the measles virus. immigrants from eastern europe appear to have slightly. lower l~vel~ of immunity to the measles virus. universal screening for immunity to meales or preemptive vac:cmauon may both be inefficient public health strategies, however further research is needed to corroborate these findings. nancy r~ss, stephane tremblay, saeeda khan, daniel crouse, mark tremblay, and jean-marie berrhelor o~ve: the speed of the rise in obesity in places like canada suggests that rather than a shift in the gcncnc_ com~sirion of the population, the root of the obesity pandemic is an environment that suprrs ~besity. this paper examines the influence of neighbourhood and metropolitan characteristics. bour~lts:. while accounting. for individual socio-demographics and behaviours, residents of neighs with a large proportmn of poorly educated individuals had higher bmis than those living in poster sessions v neighbourhoods with more highly educated individuals (p <. ). residing in a neighbourhood with a high proportion of recent immigrants was associated with lower bmi for men (p<. ), but not women. neighbourhood dwelling density, a proxy for walkability, was not associated with bm! for either sex. metropolitan sprawl was associated with higher male bmi (p=. ) but the effect was negligible for women (p=. ). bmi was significantly lower for women (p<. ) living in a city in the province of quebec, even after accounting for the influence of individual and neighbourhood covariates. conclusions: bm! was strongly patterned by individual-level social position in urban canada. the incremental influence on bmi of neighbourhood related to the neighbourhood's social conditions and not to their physical form. metropolitan sprawl was associated with higher bm! for men, a group with longer car-dependent commutes than women. the findings suggest that both individuals and their environments (both social and physical) influence the distribution of bmi in urban populations. introduction: urban environments have been linked to a range of human health issues. in singapore, prevalence of end stage renal disease (esrd) is predicted to rise ( in to in , kidney international, vol. , . the clinical and economic burden of esrd has promoted development of strategies aimed at preventing the development and progression of chronic kidney disease. these include population based screening programs such as the national kidney foundation, sin-gapore\'s (nkfs) "partnership for prevention."the program, aims to reduce incidence of esrd through comprehensive intervention and screening for early detection of urinary abnormalities, blood pressure (bp), and random blood glucose (rbg). objective of this study is to examine gender, race and age wise prevalence of elevated bp, rbg and proteinuria. methodology: this current analysis includes , subjects, age to years, who underwent screening during september and december . participants were asked to give demographic information and the history of diseases. tests were given to get clinical information such as proteinuria, blood glucose, sbp, and dbp. blood pressure abnormalities were defined according to ]nc vi criteria. proteinuria was defined as the presence of plus or greater protein (equivalent to> mg/di) on dipstick analysis. results: there were , ( . %) males. racial distribution was chinese ( . % ), malay ( . % ), indians ( . %) and others ( . % ).among participants, who were apparently "healthy" (asymptomatic and without history of dm, ht, or kd), gender and race wise % prevalence of elevated (bp> / ), rbg (> mg/di) and positive urine dipstick for protein was as follows male: ( . ; . ; . ) female:( . ; . ; . ) chinese:( . ; . ; ) malay: ( . ; . ; . ) indian:( . ; . ; . ) others: ( . ; . ; . ) total:(l . , . , . ). percentage of participants with more than one abnormality were as follows. those with bp> / mmhg, % also had rbg> mg/dl and . % had proteinuria> i. those with rbg> mgldl, % also had proteinuria> and % had bp> / mmhg. those with proteinuria> , % also had rbg> mg/dl, and % had bp> / mmhg. conclusion: we conclude that sub clinical abnormalities in urinalysis, bp and rbg readings are prevalent across all genders and racial groups in the adult population. the overlap of abnormalities, point towards the high risk for esrd as well as cardiovascular disease. this indicates the urgent need for population based programs aimed at creating awareness, and initiatives to control and retard progression of disease. introduction: various theories have been proposed that link differential psychological vulnerability to health outcomes, including developmental theories about attachment, separation, and the formation of psychopathology. research in the area of psychosomatic medicine suggests an association between attachment style and physical illness, with stress as a mediator. there are two main hypotheses explored in the present study: ( t) that individuals living with hiv who were upsychologically vulne~able" at study entry would be more likely to experience symptoms of depression, anxiety and phys ca! illness over. the course of the -month study period; and ( ) life stressors and social support would mediate the relat nship between psychological vulnerability and the psychological ~nd physical outcomes. . (rsles), state-trait anxiety inventory (stai), beck depr~ssi~n lnvento~ (bdi), and~ _ -item pbys~i symptoms inventory. we characterized participants as havmg psychological vulnerability and low resilience" as scoring above on the raas (insecure attachment) or above on the das (negative expectations about oneself). . . . . . " . . ,, . results: at baseline, % of parnc pants were classified as havmg low resilience. focusmg on anxiety, the average cumulative stai score of the low-resilience group was significandy hi~e~ than that of the high-resilience group ( . sd= . versus . sd= . ; f(l, )= . , p <. ). similar results were obtained for bdi and physical symptoms (f( , )= . , p<. and f( , )= . , p<. , respec· tively). after controlling for resilience, the effects of variance in life stres".°rs averaged over time wa~ a_sig· nificant predictor of depressive and physical symptoms, but not of anxiety. ho~e_ver, these assooan~s became non-significant when four participants with high values were removed. s id larly, after controlling for resilience, the effects of variance in social support averaged over time became insignificant. conclusion: not only did "low resilience" predict poor psychological and physical outcomes, it was also predictive of life events and social support; that is, individuals who were low in resilience were more likely to experience more life events and poorer social support than individuals who were resilient. for individuals with vulnerability to physical, psychological, and social outcomes, there is need to develop and test interventions to improve health outcomes in this group. rajat kapoor, ruby gupta, and jugal kishore introduction: young people in india represent almost one-fourth of the total population. they face significant risks related to sexual and reproductive health. many lack the information and skills neces· sary to make informed sexual and reproductive health choices. objective: to study the level of awareness about contraceptives among youth residing in urban and rural areas of delhi. method: a sample of youths was selected from barwala (rural; n= ) and balmiki basti (urban slums; n= ) the field practice areas of the department of community medicine, maulana azad medical college, in delhi. a pre-tested questionnaire was used to collect the information. when/(calen· dar time), by , fisher exact and t were appliedxwhom (authors?). statistical tests such as as appropriate. result: nearly out of ( . %) youth had heard of at least one type of contraceptive and majority ( . %) had heard about condoms. however, awareness regarding usage of contraceptives was as low as . % for terminal methods to . % for condom. condom was the best technique before and after marriage and also after childbirth. the difference in rural and urban groups was statistically signif· icant (p=. , give confidence interval too, if you provide the exact p value). youth knew that contra· ceptives were easily available ( %), mainly at dispensary ( . %) and chemist shops ( . %). only . % knew about emergency contraception. only advantage of contraceptives cited was population con· trol ( . %); however, . % believed that they could also control hiv transmission. awareness of side effects was poor among both the groups but the differences were statistically significant for pills (p= . ). media was the main source of information ( %). majority of youth was willing to discuss a~ut contraceptive with their spouse ( . %), but not with others. . % youth believed that people in their age group use contraceptives. % of youth accepted that they had used contraceptives at least once. % felt children in family is appropriate, but only . % believed in year spacing. . conclusion: awareness about contraceptives is vital for youth to protect their sexual and reproduc· tive health .. knowledge about terminal methods, emergency contraception, and side effects of various contraceptives need to be strengthened in mass media and contraceptive awareness campaigns. mdbot:ls: elderly aged + were interviewed in poor communities in beirut the capital of f:ebanon, ~e of which is a palestinia~. refugee camp. depression was assessed using the i -item geriat· nc depressi~n score (~l?s- ). specific q~estions relating to the aspects of religiosity were asked as well as questions perta rung to demographic, psychosocial and health-related variables. results: depression was prevalent in % of the interviewed elderly with the highest proportion being in the palestinian refugee camp ( %). mosque attendance significantly reduced the odds of being depressed only for the palestinian respondents. depression was further associated, in particular communities, with low satisfaction with income, functional disability, and illness during last year. condiuion: religious practice, which was only related to depression among the refugee population, is discussed as more of an indicator of social cohesion, solidarity than an aspect of religiosity. furthermore, it has been suggested that minority groups rely on religious stratagems to cope with their pain more than other groups. implications of findings are discussed with particular relevance to the populations studied. nearly thirty percent of india's population lives in urban areas. the outcome of urbanization has resulted in rapid growth of urban slums. in a mega-city chennai, the slum populations ( . percent) face greater health hazards due to overcrowding, poor sanitation, lack of access to safe drinking water and environmental pollution. amongst the slum population the health of women and children are most neglected, resulting in burden of both communicable and non-communicable diseases. the focus of the paper is to present the epidemiology profile of children (below years) in slums of chennai, their health status, hygiene and nutritional factors, the social response to health, the trends in child health and urbanization over a decade, the health accessibility factors, the role of gender in health care and assessment impact of health education to children. the available data prove that child health in slums is worse than rural areas. though the slum population is decreasing there is a need to explore the program intervention and carry out surveys for collecting data on some specific health implications of the slum children. objective: during the summer of there was a heat wave in central europe, producing an excess number of deaths in many countries including spain. the city of barcelona was one of the places in spain where temperatures often surpassed the excess heat threshold related with an increase in mortality. the objective of the study was to determine whether the excess of mortality which occurred in barcelona was dependent on age, gender or educational level, important but often neglected dimensions of heat wave-related studies. methods: barcelona, the second largest city in spain ( , , inhabitants in ) , is located on the north eastern coast. we included all deaths of residents of barcelona older than years that occurred in the city during the months of june, july and august of and also during the same months during the preceding years. all the analyses were performed for each sex separately. the daily number of deaths in the year was compared with the mean daily number of deaths for the period - for each educational level. poisson regression models were fitted to obtain the rr of death in with respect to the period - for each educational level and age group. results: the excess of mortality during that summer was more important for women than for men and among older ages. although the increase was observed in all educational groups, in some age-groups the increase was larger for people with less than primary education. for example, for women in the group aged - , the rr of dying for compared to - for women with no education was . ( %ci: . - - ) and for women with primary education or higher was . ( %ci: . - . ). when we consider the number of excess deaths, for total mortality (>= years) the excess numbers were higher for those with no education ( . for women and . for men) and those with less than primary education ( . for women and - for men) than those with more than primary edm:ation ( . for women and - . for men). conclusion: age, gender and educational level were important in the barcelona heat wave. it is necessary to implement response plans to reduce heat morbidity and mortality. policies should he addressed to all population but also focusing particularly to the oldest population of low educational level. introduction: recently there has been much public discourse on homelessness and its imp~ct on health. measures have intensified to get people off the street into permanent housing. for maximum v poster sessions success it is important to first determine the needs of those to be housed. their views on housing and support requirements have to be considered, as th~y ar~ the ones affected. as few res.earch studies mclude the perspectives of homeless people themselves, httle is known on ho~ they e~penence the mpacrs on their health and what kinds of supports they believe they need to obtain housing and stay housed. the purpose of this study was to add the perspectives of homeless people to the discourse, based in the assumption that they are the experts on their own situations and needs. housing is seen as a major deter· minant of health. the research questions were: what are the effects of homelessness on health? what kind of supports are needed for homeless people to get off the street? both questions sought the views of homeless individuals on these issues. methods: this study is qualitative, descriptive, exploratory. semi-structured interviews were conducted with homeless persons on street corners, in parks and drop-ins. subsequently a thematic analysis was carried out on the data. results: the findings show that individuals' experiences of homelessness deeply affect their health. apart from physical impacts all talked about how their emotional health and self-esteem are affected. the system itself, rather than being useful, was often perceived as disabling and dehumanizing, resulting in hopelessness and resignation to life on the street. neither welfare nor minimum wage jobs are sufficient to live and pay rent. educational upgrading and job training, rather than enforced idleness, are desired by most initially. in general, the longer persons were homeless, the more they fell into patterned cycles of shelter /street life, temporary employment /unemployment, sometimes addictions and often unsuccessful housing episodes. conclusions: participants believe that resources should be put into training and education for acquisition of job skills and confidence to avoid homelessness or minimize its duration. to afford housing low-income people and welfare recipients need subsidies. early interventions, 'housing first', more humane and efficient processes for negotiating the welfare system, respectful treatment by service providers and some extra financial support in crisis initially, were suggested as helpful for avoiding homelessness altogether or helping most homeless people to leave the street. this study is a national homelessness initiative funded analysis examining the experiences and perceptions of street youth vis-a-vis their health/wellness status. through in-depth interviews with street youth in halifax, montreal, toronto, calgary, ottawa and vancouver, this paper explores healthy and not-so healthy practices of young people living on the street. qualitative interviews with health/ social service providers complement the analysis. more specifically, the investigation uncovers how street youth understand health and wellness; how they define good and bad health; and their experiences in accessing diverse health services. findings suggest that living on the street impacts physical, emotional and spiritual well·being, leading to cycles of despair, anger and helplessness. the majority of street youth services act as "brokers" for young people who desire health care services yet refuse to approach formal heal~h care organizational structures. as such, this study also provides case examples of promising youth services across canada who are emerging as critical spaces for street youth to heal from the ravages of ~treet cultur~. as young people increasingly make up a substantial proportion of the homeless population in canada, it becomes urgent to explore the multiple ways in which we can support them to regain a sense of wellbeing and "citizenship." p - (c) health and livelihood implications of marginalization of slum dwellers in provision of water and sanitation services in nairobi city elizabeth kimani, eliya zulu, and chi-chi undie . ~ntrodfldion: un-habitat estimates that % of urban residents in kenya live in slums; yet due to their illegal status, they are not provided with basic services such as water sanitation and health care. ~nseque~tly, the services are provided by vendors who typically provide' poor services at exorbitant prices .. this paper investigates how the inequality in provision of basic services affects health and livelihood circumstances of the poor residents of nairobi slums . . methods: this study uses qualitative and quantitative data collected through the ongoing longitudmal .health and demographic study conducted by the african population and health research center m slum communities in n ·rob" w d · · · · ai . e use escnpnve analytical and qualitative techmques to assess h~w concerns relating to water supply and environmental sanitation services rank among the c~mmumty's general and health needs/concerns, and how this context affect their health and livelihood circumstances. results: water ( %) and sanitation ( %) were the most commonly reported health needs and also key among general needs (after unemployment) among slum dwellers. water and sanitation services are mainly provided by exploitative vendors who operate without any regulatory mechanism and charge exorbitantly for their poor services. for instance slum residents pay about times more for water than non-slum households. water supply is irregular and residents often go for a week without water; prices are hiked and hygiene is compromised during such shortages. most houses do not have toilets and residents have to use commercial toilets or adopt unorthodox means such as disposing of their excreta in the nearby bushes or plastic bags that they throw in the open. as a direct result of the poor environmental conditions and inaccessible health services, slum residents are not only sicker, they are also less likely to utilise health services and consequently, more likely to die than non-slum residents. for instance, the prevalence of diarrhoea among children in the slums was % compared to % in nairobi as a whole and % in rural areas, while under-five mortality rates were / , / and / respectively. the results demonstrate the need for change in governments' policies that deprive the rapidly expanding urban poor population of basic services and regulatory mechanisms that would protect them from exploitation. the poor environmental sanitation and lack of basic services compound slum residents' poverty since they pay much more for the relatively poor services than their non-slum counterparts, and also increase their vulnerability to infectious diseases and mortality. since iepas've been working in harm reduction becoming the pioneer in latin america that brought this methodology for brazil. nowadays the main goal is to expand this strategy in the region and strive to change the drug policy in brazil. in this way harm reduction: health and citizenship program work in two areas to promote the citizenship of !du and for people living with hiv/aids offering law assistance for this population and outreach work for needle exchange to reduce damages and dissemination of hiv/aids/hepatit is. the methodology used in outreach work is peer education, needle exchange, condoms and folders distribution to reduce damages and the dissemination of diseases like hiv/aids/hepatitis besides counseling to search for basic health and rights are activities in this program. law attendance for the target population at iepas headquarters every week in order to provide law assistance that includes only supply people with correct law information or file a lawsuit. presentations in harm reduction and drug policy to expand these subjects for police chiefs and governmental in the last year attended !du and nidu reached and . needles and syringes exchanged. in law assistance ( people living with aids, drug users, inject drug users, were not in profile) people attended. lawsuits filed lawsuits in current activity. broadcasting of the harm reduction strategies by the press helps to move the public opinion, gather supporters and diminish controversies regarding such actions. a majority number of police officer doesn't know the existence of this policy. it's still polemic discuss this subject in this part of population. women remain one of the most under seviced segments of the nigerian populationand a focus on their health and other needs is of special importance.the singular focus of the nigerian family welfare program is mostly on demographic targets by seeking to increase contraceptive prevalence.this has meant the neglect of many areas of of women's reproductive health. reproductive health is affected by a variety of socio-cultural and biological factors on on e hand and the quality of the service delivery system and its responsiveness on the other.a woman's based approach is one which responds to the needs of the adult woman and adolescent girls in a culturally sensitive manner.women's unequal access to resources including health care is well known in nigeria in which stark gender disparities are a reality .maternal health activities are unbalanced,focusi ng on immunisation and provision of iron and folic acid,rather than on sustained care of women or on the detection and referral of high risk cases. a cross-sectional study of a municipal government -owned hospitalfrom each of the geo-political regions in igeria was carried out (atotal of ce~ters) .. as _part ~f t~e re.search, the h~spital records were uesd as a background in addition to a -week mtens ve mvesuganon m the obstemc and gynecology departments. . . . : little is known for example of the extent of gynecological morbtdtty among women; the little known suggest that teh majority suffer from one or more reproductive tr~ct infect~ons. although abortion is widespread, it continues to be performed under ilegal and unsafe condmons. with the growing v poster sessions hiv pandemic, while high riskgroups such ascomn;iercial sex workers and their clients have been studied, little has been accomplished in the large populat ns, and particularly among women, regardmgstd an hiv education. . . conclusions: programs of various governmentalor non-governmental agen,c es to mvolve strategies to broaden the narrow focus of services, and more importan~, to put wo~en s reproducnve health services and information needs in the forefront are urgently required. there is a n~d to reonent commuication and education activities to incorprate a wider interpretation of reproducnve health, to focus on the varying information needs of women, men, and youth and to the media most suitable to convey information to these diverse groups on reproductive health. introduction: it is estimated that there are - youths living on the streets, on their own with the assistance of social services or in poverty with a parent in ottawa. this population is under-serviced in many areas including health care. many of these adolescents are uncomfortable or unable to access the health care system through conventional methods and have been treated in walk-in clinics and emergency rooms without ongoing follow up. in march , the ontario government provided the ct lamont institute with a grant to open an interdisciplinary and teaching medical/dental clinic for street youth in a drop-in center in downtown ottawa. bringing community organizations together to provide primary medical care and dental hygiene to the streetyouths of ottawa ages - , it is staffed by a family physician, family medicine residents, a nurse practitioner, public health nurses, a dental hygienist, dental hygiene students and a chiropodist who link to social services already provided at the centre including housing, life skills programs and counselling. project objectives: . to improve the health of high risk youth by providing accessible, coordinated, comprehensive health and dental care to vulnerable adolescents. . to model and teach interdisciplinary adolescent care to undergraduate medical students, family medicine residents and dental hygiene students. methods: non-randomized, mixed method design involving a process and impact evaluation. data collection-qualitative:a) semi-structured interviews b) focus groups with youth quantitative:a) electronic medical records for months b) records (budget, photos, project information). results: in progress-results from first months available in august . early results suggest that locating the clinic in a safe and familiar environment is a key factor in attracting the over youths the clinic has seen to date. other findings include the prevalence of preventative interventions including vaccinations, std testing and prenatal care. the poster presentation will present these and other impacts that the clinic has had on the health of the youth in the first year of the study. conclusions: ) the clinic has improved the health of ottawa streetyouth and will continue beyond the initial pilot project phase. ) this project demonstrates that with strong community partnerships, it is possible meet make healthcare more accessible for urban youth. right to health care campaign by s.j.chander, community health cell, bangalore, india. introduction: the people's health movement in india launched a campaign known as 'right to health care' during the silver jubilee year of the alma ata declaration of 'health for all' by ad in collahoration with the national human rights commission (nhrc). the aim of the campaign was to establish the 'right to health care' as a basic human right and to address structural deficiencies in the pubic health care system and unregulated private sector . . methods: as part of the campaign a public hearing was organized in a slum in bangalore. former chairman of the nhrc chaired the hearing panel, consisting of a senior health official and other eminent people in the city. detailed documentation of individual case studies on 'denial of access to health care' in different parts of the city was carried out using a specific format. the focus was on cases where denial of health services has led to loss of life, physical damage or severe financial losses to the patient. results: _fourte_en people, except one who had accessed a private clinic, presented their testimonies of their experiences m accessing the public health care services in government health centres. all the people, e_xcept_ one person who spontaneously shared her testimony, were identified by the organizations worki_ng with the slum dwellers. corruption and ill treatment were the main issues of concern to the people. five of the fourteen testimonies presented resulted in death due to negligence. the public health cen· n:s not only demand money for the supposedly free services but also ill-treats them with verbal abuse. five of these fourteen case studies were presented before the national human right commission. the poster sessions v nhrc has asked the government health officials to look into the cases that were presented and to rectify the anomalies in the system. as a result of the public hearing held in the slum, the nhrc identified urban health as one of key areas for focus during the national public hearing. cond#sion: a campaign is necessary to check the corrupted public health care system and a covetous private health care system. it helps people to understand the structure and functioning of public health care system and to assert their right to assess heath care. the public hearings or people's tribunals held during the campaign are an instrument in making the public health system accountable. ps- (a) violence among women who inject drugs nadia fairbairn, jo-anne stoltz, evan wood, kathy li, julio montaner, and thomas kerr background/object ives: violence is a major cause of morbidity and mortality among women living in urban settings. though it is widely recognized that violence is endemic to inner-city illicit drug markets, little is known about violence experienced by women injection drug users (!du). therefore, the present analyses were conducted to evaluate the prevalence of, and characteristics associated with, experiencing violence among a cohort of female idu in vancouver. methods: we evaluated factors associated with violence among female participants enrolled in the vancouver injection drug user study (vidus) using univariate analyses. we also examined self-reported relationships with the perpetrator of the attack and the nature of the violent attack. results: of the active iou followed between december , and may , , ( . %) had experienced violence during the last six months. variables positively associated with experiencing violence included: homelessness (or= . , % ci: . - . , p < . ), public injecting (or= . , % ci: . - . , p < . ), frequent crack use (or= . , % ci: . - . , p < . ), recent incarceration (or = . , % cl: . - . , p < . ), receiving help injecting (or = . , % cl: . - . , p < . ), shooting gallery attendance (or = . , % ci: . - . , p < . ), sex trade work (or = . , % cl: . - . , p < . ), frequent heroin injection (or= . , % cl: . - . , p < . ), and residence in the downtown eastside (odds ratio [or] = . , % ci: . - . , p < . ). variables negatively associated with experiencing violence included: being married or common-law (or = . . % ci: . - . , p < . ) and being in methadone treatment (or = . , % ci: . - . , p < . ). the most common perpetrators of the attack were acquaintances ( . %), strangers ( . %), police ( . %), or dealers ( . %). attacks were most frequently in the form of beatings ( . %), robberies ( . %), and assault with a weapon ( . %). conclusion: violence was a common experience among women !du in this cohort. being the victim of violence was associated with various factors, including homelessness and public injecting. these findings indicate the need for targeted prevention and support services, such as supportive housing programs and safer injection facilities, for women iou. introduction: although research on determinants of tobacco use among arab youth has been carried out at several ecologic levels, such research has included conceptual models and has compared the two different types of tobacco that are most commonly used among the lebanese youth, namely cigarette and argileh. this study uses the ecological model to investigate differences between the genders as related to the determinants of both cigarette and argileh use among youth. methodology: quantitative data was collected from youth in economically disadvantaged urban communities in beirut, the capital of lebanon. results: the results indicated that there are differences by gender at a variety of ecological levels of influence on smoking behavior. for cigarettes, gender differences were found in knowledge, peer, family, and community influences. for argileh, gender differences were found at the peer, family, and community l.evels. the differential prevalence of cigarette and argileh smoking between boys and girls s therefore understandable and partially explained by the variation in the interpersonal and community envi.ronment which surrounds them. interventions therefore need to be tailored to the specific needs of boys and girls. introduction: the objective of this study was to assess the relationship between parents' employment status and children' health among professional immigrant families in vancouver. our target communmes v poster sessions included immigrants from five ethnicity groups: south korean, indian, chine~e, ~ussian, and irani~ with professional degrees (i.e., mds, lawyers, engineers, ma?~ger~, and uru~ers ty professors) w h no relevant job to their professions and those who had been hvmg m the studied area at least for months. methodology: the participants were recruited by collaboration from three local community agencies and were interviewed individually during the fall of . ra#lts: totally, complete interviews were analyzed: from south-east asia, from south asia, from russia and other eastern europe. overall, . % were employed, . % were underemployed, % indicated they were unemployed. overall, . % were not satisfied with their current job. russians and other eastern europeans were most likely satisfied with their current job, while south-east asians were most satisfied from their life in canada. about % indicated that their spouses were not satisfied with their life in canada, while % believed that their children are very satisfied from their life in canada. in addition, around % said they were not satisfied from their family relationship in canada. while most of the responders ranked their own and their spouses' health status as either poor or very poor, jut % indicated that their first child's health was very poor. in most cases they ranked their children's health as excellent or very good. the results of this pilot study show that there is a need to create culturally specific child health and behavioral scales when conducting research in immigrant communities. for instance, in many asian cultures, it is customary for a parent either to praise their children profusely, or to condemn them. this cultural practice, called "saving face," can affect research results, as it might have affected the present study. necessary steps, therefore, are needed to revise the current standard health and behavioral scales for further studies by developing a new scale that is more relevant and culturally sensitive to the targeted immigrant families. metboda: database: national health survey (ministry of health www.msc.es). two thousand interviews were performed among madrid population ( . % of the whole); corresponded to older adults ( . % of the . million aged years and over). study sample constitutes . % ( out of ) of those older adults, who live in urban areas. demographic structure (by age and gender) of this population in relation to health services use (medical consultations, dentist visits, emergence services, hospitalisation) was studied using general linear model univariate procedure. a p . ), while age was associated with emergence services use ( % of the population: %, % and % of each age group) and hos~italisation ( % .oft~~ population: %, % and %, of each age ~oup) (p . ) was fou~d with respect to dennst v s ts ( % vs %), medical consultations ( % vs %), and emergence services use ( % vs %), while an association (p= . ) was found according to hospitalisation ( % vs %). age. an~ g~der interaction effect on health services use was not found (p> . ), but a trend towards bosp tal sanon (p= . ) could be considered. concl.uions: demographic structure of urban older adults is associated with two of the four health se~ices use studi~. a relation.ship ber_ween age. and hospital services use (emergence units and hospitalisanon), but not with ~ut-hosp tal sei:vices (medical and dentist consultations), was found. in addition ro age, gender also contnbutes to explam hospitalisation. . sexua experiences. we exammed the prevalence expenences relation to ethnic origin and other sociodemographic variables as wc i as y j die relation between unwanted sexual experiences, depression and agreuion. we did so for boys and prts separately. mdhods: data on unwanted sexual expcric:nces, depressive symptoms (ce.s-d), aggrc:uion (bohi-di and sociodemographic facron were collected by self-report quescionnairc:s administettd to students in the: nd grade (aged - ) of secondary schools in amsterdam, the netherlands. data on the nature ol unwanted sexual experiences were collected during penonal interviews by trained schoolnursn. ltaijtj: overall prevalences of unwanted sexual experiences for boys and girls were . % and . % respectively. unwanted sexual experiences were more often ttported by turkish ( . %), moroc· an ( . %) and surinamese/anrillian boys ( . %) than by dutch boys ( . %). moroccan and turkish girls, however, reported fewer unwanted sexual experiences (respectively . and . %) than durch girls did ( . %). depressive symptoms(or= . , cl= . - . ) covert agression ( r• . , cl• . - . ) and cmrt aggression (or= . , cl• . - . ) were more common in girls with an unwanted sexual experi· met. boys with an unwanted sexual experience reported more depressive symptoms (or= . ; cl• i . .l· . ) and oven agression (or= . , cl= . - . ) . of the reported unwanted sexual experiences rnpec· timy . % and . % were confirmed by male and female adolescents during a personal interview. cond sion: we ..:an conclude that the prevalence of unwanted sexual experiences among turkish and moroccan boys is disturbing. it is possible that unwanted sexual experiences are more reported hy boys who belong to a religion or culture where the virginity of girls is a maner of family honour and talking about sexuality is taboo. more boys than girls did not confirm their initial disdosurc of an lllwalltc:d sexual experience. the low rates of disclosure among boys suggcsu a necd to educ.:atc hcahh care providen and others who work with migrant boys in the recognition and repomng of exu.il ... iction. viramin a aupplc:tmntation i at .h'yo, till far from tafl'eted %. feedinit pracn~:n panku· lerty for new born earn demand lot of educatton ernpha a• cxdu ve hrealt fecdtnit for dnared rcnoj of months was observtd in only .s% of childrrn thoulh colckturm w. givm n rn% of mwly horn ct.ildrm. the proportion of children hclow- waz (malnounshrdl .con" a• h!jh •• . % anj "rt'i· acimy tc.. compared to data. mother's ~alth: from all is womm in ttprod~uvr •ill' poup, % were married and among marned w~ .\ % only w\"rt' u mic wmr cnntr.-:cruve mt h· odl % were married bdorc thc •ar of yean and % had thnr ftnc prcicnancy hcftitt dlt' •icr nf yean. the lt'f'vicn are not uutfactory or they arc adequate but nae unh ed opumally. of thote' l'h mothen who had deliverrd in last one year, % had nailed ntmaral eum nat on ira" oncc, .~o-... bad matt rhan four ttmn and ma ortty had heir tetanus toxotd tnin,"t or"'" nlht "'"'"· ljn r ned rn· win ronductrd . % dchvcnn and % had home deh\'t'oc'i. ~md~: the tervtcn unbud or u led are !tu than dnarame. the wr· l'kft provided are inadequate and on dechm reprcwnttng a looun t ~p of h hnto good coytti\#' ol wr· ncn. l!.ckground chanpng pnoriry cannoc be ruled out u °"" of thc coatnbutory bc f. ps-ii ia) dcpn:wioa aad anuccy ia mip'mu ia awccr._ many de wn, witco tui~bmjer. jack dekker, aart·jan lttkman, wim gonmc:n. and amoud verhoeff ~ a dutch commumry-bucd icudy thawed -moarh•·prc:yalm«i al . ' . kw anx · ay daorden and . % foi' dqrasion m anmttdam. nm .. p tficantly hlllhn than dwwhrft .. dw ~thew diffamca m pttyalcnca att probably rdarcd to tlk' largr populanoa of napaan ..\mturdam. <turkish %, moroccan %, and surinam % . lndttd. ic'wt'll ltudla hatt ~ ~ high prevalena rata among migrant poupi in rbe ncdwrlands. howc'ytt au ttlluchn iuffenod from wry low raporne rara, or med screnung talel thac lack a ~y yabdarcd ~ in order to study the prevalence of depression and anxiety, and the (barriers to) use of mental health care among the different ethnic groups the following study was recently conducted: . the study consisted of a two-step approach. the first step was mcl~ded m the ~ h ith survey of (ahs), and consisted of three screening scales for depression and aruaety (klo, g::q- and mhl- ). in this survey all respondents were asked_ permission for~ second app~ :' t consisted of a structured interview containing the cidi for aruaety and depression, and questtollllalres on health care seeking, amongst others. all respondents who gave permission for a second approachwere invited by jetter for a suuctured interview with multilingual interviewers at home at a preset date and time in the following week. . in total, dutch, turkish, moroccan and surinam respondents took part in the ahs and gave permission for a second approach. in the second step, fo~ ~ tur~h, m~roc can surinamese and dutch respondents, information from the extensive interview was available (res~nse rates between and % ). since the data collection was completed only recently (june ), prevalence estimates can be presented at the conference for the first time. we have shown that with this approach it is feasible to achieve an acceptable response rate in a study on mental health among migrants. therefore we expect that this study will provide reli· able estimates of depression and anxiety in the turkish, moroccan and surinam migrants in amstw! ~· for the first time. in addition, insight into mechanisms underlying the differences between and within ethnic groups and into barriers to mental health care will provide pretexts for the improvement of pre· vention and mental health care for migrant groups. this study aimed to determine spatial patterns of mortality and morbidity of five major health problems in an urban environment: homicides, pregnancy among adolescents ((< years old), asthma hospitalization among young children(< years old) and two mosquito-borne diseasesdengue and visceral leishmaniasis, during - . all events were obtained through the city health database and, subsequently, geoproccsscd using the address of residence and the geographical and administrative division of the municipality, composed by unit of planning (up), which in tum were formed, each one, by census tract units. two research questions were investigated: are there spatial patterns to the events dis· tribution, and moreover, are these patterns overlapping across space? we use thematic maps, index of comparative mortality/morbidity by up and the overlapped rank of the th worse up rates for each event. a spatial pattern of high rates of homicides, proportion of young mothers and hospitalization of asthma were overlapping in areas social and economically disadvantaged. for mosquito-borne diseases, high rates with great dispersion were found in unprivileged areas in contrast with very low rares among privileged ones. these results pointed toward a coexistence of heavier burden of diseases for those living in areas of the city where misery, poverty, lack of political public health may be modulating social health problems. a possible environmental intervention in one mosquito•bome disease might be playing a role in the occurrence of other. although with limitations, this study may provide useful information for a joint urban planning under the public perspective, articulated for use in health impact assessment. jalil safaei bdrod#aion: the association of socioeconomic status (ses), usually measured by income, and health status is an established result in bcalth studies. the poor and low income individuals have lower health sta· tus then_ those with higher incomes. in general. such finding has been usually obtained from sample surveys on speafic populations. a problem with many sample survey$ is that their results are not comparable aaoss ~ndaries as they may use different sampling methods, ask different questions, categorize the answers differently, or define groups differently. moreover, the sample data need to be standardized using the demographic: katurea of a ~ population. this study, however, uses the national population health survey (nphs) cycle public use mictodata files which is based on a common survey template ·~~three~ area in canada, namely montreal, toronto, and vancouver. it also utili .es the built-m stanclatdizaaon of the nphs data which accounts for its complex survey design. . ~:the stu~ usc:s two well-known measures of health inequalitythe relative index of meqaality and die concentranon indexto capture the extent of income related health inequality among poster sessions v urban female and male populations in each of the three metropolitan areas. personal income is classified into ten groups by the nphs with "no income" as the first group and "more than $ , " as the last. health status is measured by three variables -having a chronic condition (chc), self assessed health (sah), and health utility index (hui) -using appropriate indices. alternative formulations are used to calculate the standard deviations of the estimated or calculated measures. the findings of the study suggest that the measured health inequality depends on the health measure used. for chc and hui the measured inequality indices do indicate poorer health for lower income individulas, however, they are not statistically insignificant. health inequalities are more pronounced when health is measured by sah. the results do not support any systematic ranking of the three metropolitan areas in terms of health inequalities. they do not reveal any systematic pattern of inequality between men and women, either. conclusions: despite the use of highly aggregated nphs data, income related health disparities are observed in the three metropolitan areas in canada. this is more the case with self perceived (sah) health. such disparities are preventable and call for broader health policies that address poverty and low income among other social determinants of health. introduction: the analysis of health indicators under the spatial perspective is configured as an important instrument in the detection of intra-urban differentials. this study aimed to examine the spatial distribution of the births occurred in belo horizonte, in , analyzing the presence of spatial clusters of health indicators for newborns (rn) and their mothers, using data from the information system on live birth database (sinasc). method: for each covered area of the basic units of health (ubs), we calculated the proportion of: adolescent mothers, mothers with less than years of schooling, first pregnancy, mothers with four or more pregnancies, dead babies born on previous pregnancies, stillbirths, cesarean section, less than four prenatal care attendance, moderate and severe hypoxemia in the st and th minutes of life, low or very low birth weight. we used empiric bayesian methods for smoothing the estimates. for spatial analysis, the indicators obtained from the global moran (i) index and local indicators of spatial association (lisa) were used. maps were built to allow the visualization of the spatial clusters. in all analysis, significance statistics was considered p~ . . results: a total of , births of residents in belo horizonte were registered in i. the estimated bayesian proportions for the entire municipality was close to the one observed for all variables. analysis using lisa showed the presence of relevant spatial clusters for adolescent and low educated mothers, dead babies form previous pregnancies, cesarean section, low attendance to the prenatal care especially in area with low socio-demographic characteristics. three areas presented consistent clusters, with important spatial auto-correlation for almost all studied indicators. conclusion: the used methodology was configured as a great instrument of detection risk areas where clustering occurs. it can easily be incorporated in any surveillance system as a mechanism for controlling events related to births in the municipality. moreover, it can be applied to discriminate target areas for prompt public health interventions, such as improving health services access and the consolidation of better obstetric practices. introduction: gentrification, the displacement of low income and non-majority people out of longtime neighborhoods and residences is a global phenomenon. it has been identified as occurring in both developed and less developed countries and as inequality persists or increases, many communities are vulnerable to disruption and loss. while there may be some benefits to gentrification, these benefits are less likely to impact those who have been forced to move out of a gentrifying community or those who remain but economically stressed. . . . . this paper lays out a theoretical framework for dent fymg and ~ddressm~. the_ health consequences of gentrification on residents living in a community prior .to o.r durmg gent~ ~ cat. n. by drawing on the literature of housing, sociology, health and urban plannmg, t places genmf catt~n and neighborhood change into the context of other forces affecting th~ .hea.lth of vulnerable populations. it then proposes solutions to prevent or mitigate the impacts of genmf cat on. results: four main categories of consequences potentiallr re~ult from ~entr~fica~~n: !'°°r housing· related issues, spatial effects, mental health impacts and contr bunons to racial ~spanttes m heal~. the housing issues include increased susceptibility to asthma, lead exposure, allergiesl~topy an~. acetdents/ injuries. spatial effects include reduced access to health ~are, reduce~ access to obslttadinonal food sources, decreased physical activity, and increased obesity. the __ pnmary mental health effects_ :ire increased stress increased risk of depression and disruption of trad t onal support networks. in addinon to the above he~lth issues, gentrification has the potential to increase racial disparities in health by reduc· ing access to long term and multi-culturally experienced health care provide~s. conclusions: public health practice provides a framework for addressmg the health consequences of gentrification. in this context primary prevention would involve preventing gentrification in the first place along with a renewed commitment to helping distressed communities a~~ im_proving the quality ~f life for long term residents. the next layer of meeting the challenges of gentrification would be to assjst long rime residents to stay in a community and thus potentially allowing them to participate in the bene~ts of gentrification (such as better public services). only if all these efforts fail -and these other prevennon strategies must be a priority, public policy should then work to help people and instirutions move to other communities through grants and the provision of alternative safe affordable housing and neighborhoods. sarah romans, marsha cohen, and tonia forte lnh'odlletion: there has been sustained interest in urban rural (ur) differences in mental health over the last years of epidemiological research, with most studies reporting higher urban rates of mor· bidity, particularly when psychotic disorders have been studied. most recently, in britain, urban rates of non-psychotic disorder were greater than rural and semi-rural rates, both before and after the more adverse circumstances of urban dwellers were considered (paykel et al ) . surprisingly, there were no ur differences in help seeking. in canada, wang ( ) found greater urban rates for major depression only after he controlled for the confounding effects of race, immigration, employment and marital status, a result reminiscent of work from the us (blazer et ) . rural participants were less likely to have sought help for their mental health problems. in this study, we sought to examine urban/rural differences in rates of depression and help seeking in canada. method; data came from the canadian community health survey . , a community survey conducted by statistics canada of people aged and older, with the total sample size of , respon· dents, % response. analyses used weighted data; differences were assessed by chi-squared. ra.its: bivariate cross-tabulations showed a modest increase in month depression rates for urban ( . %) over rural ( . %, p= . ) dwellers; there were no ur differences when the sample was examined separately by gender and age group ( - , - , - ) . in general, more urban ( . %) than rural people ( . %, p= . ) had sought mental health treatment in the past year. there was no ur difference in helping seeking amongst those with depression (u . %, r . % ns). amongst the whole population, helping seeking was gendered with more urban men accessing help ( . %) than rural men ( . %, p= . ); this did not apply for women ( . % vs . % p= . ). ~ons: the urban-rural demographic continues to generate intriguing findings, even recently when internal migration is common and people can seek out the environment most conducive to their health, ~th physical and mental. people with depression are a disadvantaged, frequently stigmatized group, with ~r quality of life a_nd often impaired function. unlike many other factors associated wi~h urban or rural hfe per se, depression can be treated. the low help seeking rates is a cause for concern, m both the ur~n and_ rural populations. it behooves researchers, policy makers and service planners to ensutt effective services are available for both humane and economic reasons. methods: using united states census income data, we assigned the manhattan community districts to two major socioeconomic groups, manhattan i and ii. manhattan i is composed of community districts with average household incomes above the median for new york city; manhattan ii is those below. with public new york city department of health death records and us census data, we calculated a "standard" new york city population and estimated mortality rate distributions for manhattan i and ii. we then compared these age-adjusted actual mortality distributions with a standard t-test. results: we explored premature deaths using several cut-off points (before the ages of , , and ), and with subcomparisons for males and females. every comparison showed the wealthier area, manhattan i, to have significantly lower premature mortality rates than the lower income manhattan ii. further, we compared age-adjusted mortality rates among the city's five boroughs, and found no significant differences based on local geography alone. conclusions: these findings suggest that in manhattan, characterized by its extremes of wealth and poverty, health status, as measured by premature mortality, does vary significantly with the local income level. in manhattan, the relative average income by community district varies as much as : . this ratio is greater than that found in the other cities we have studied: for example, the range among tokyo's kus is half that in manhattan, or about : . paris has shown the longest life expectancy and changing premature mortality rates. from our preliminary work, we expect to find less variation in premature mortality rates in comparable cities. this study will continue to explore the relationship of premature mortality rates and life expectancy to income levels and different health systems among wcp cities with a view to measuring health policy options. introduction: according to the world health organization (who), smoking-related illness is currently the world's second major cause of death, currently responsible for one out of ten adult deaths worldwide. the who's framework convention on tobacco control (fctc) aims to reduce tobaccorelated disease and deaths by changing national public policies. mexico, which, according to the who, had smoking prevalences of % among adults in and % among health care providers (hcps) in , ratified the fctc in . objective: to examine knowledge of and attitudes towards cigarette smoking and smoking cessation among hcps, and clinical practices regarding smoking cessation. methods: in june , a convenience sample of hcps from one public clinic in urban oaxaca, mexico, part of mexico's national network of public health care clinics, were interviewed in spanish using a verbally administered questionnaire that was standard among all participants. during primary care outpatient visits, hcps were observed treating patients to assess the relative importance of smoking cessation as a health care priority. results: of the hcps interviewed, including ten physicians, three nurses, and five medical students, % reported smoking regularly. all hcps reported assessing patients' history of smoking, knowledge of the health risks associated with smoking, and feeling qualified to discuss these risks with patients. all hcps reported counseling patients who currently smoked to quit. all hcps reported recommending nicotine replacement therapy (eg., patch and/or gum) and/or behavioral therapy (eg., psychologist, support groups) to patients who smoked. all hcps reported that there was no government funding for smoking cessation, and that all costs associated with smoking cessation were patients' out-of-pocket expenses. observation of hcp interaction with patients revealed that hcps always inquired about smoking history with new patients and rarely inquired about smoking history with returning patients. hcps were not observed counseling patients who reported current smoking on smoking cessation methods and its benefits. observation of the clinical environment suggested a focus on preventative child health (eg., immunization, water-borne illnesses), family planning, and chronic diseases (eg., diabetes, hypertension). conclusions: while the mexican government has made smoking cessation a public health priority and hcps report addressing smoking cessation, observation of hcps suggests: ) smoking status is assessed only in new patients; and ) smoking cessation methods are not addresse~. observ_atio~ of hcps and the clinical environment in a public clinic in oaxaca suggests that smoking cessation s of lower priority than other heath care issues. p - (a) urban agriculture and food and nutrition security in kampala, uganda fiona yeudall, renee sebastian, abdelrahman lubowa, selahadin ibrahim, and donald cole introduction: urban agriculture is an important livelihood strategy contributing to household food security by increasing access and availability to food in urban settings (koc et al., ) . the purpose of poster sessions v rhis study was to examine relationships between child nutritional securiry outcomes, household food security, and urban agriculture activiries in kampala, uga~da. . . questionnaires assessing socio-demographic, farmmg and household food secunry (hfsi characreristics were administered to households. food diversiry was ~lculate~ from ~e number of foods consumed over hours for one child ( - years) per household. heigh~ weight,. nud-upper·ann· circumference (muac) and tricep skinfolds (tsf) were measured for the mdex child. z-sc.ores for height-for·age (haz), weighr-for-age (waz) and body mass index (zbmi) were ~~ulated usmg cen· rres for disease control and prevenrion reference data. z-scores for body composition measures were calculated using nhanes i and ii data for african americans. the lms method was used to c~.t for skewed z·score indices. all dara was checked for normaliry and univariable and backward mulnvanablc linear regression analysis conducted. ruwlts: household food securiry was significantly associated with wealth (b= . , p< 'a acre were more dependenr on assets for hfs. although sex of head of household was ~ot related to j-:ifs, it modi· fied relationships in rhar female headed households had greater food securtry when fai:mmg less than , acre compared ro male headed households, and vice versa. hfs was significantly associated with food diversiry (s= . , p). urbanization, especially in developing countries, has substantially increased the vulnerability of rhe mass of low-income urban dwellers. the livelihoods and quality of life for many of the poor espe· cially in larin america, asia, and africa, have deteriorated significantly over the years. urban areas are increasingly unable to provide for their populations, resulting in poverry, massive unemploymenr, job cuts, poor housing, lack of or poor public services, and a compromised health status. botswana, a country rhat lies in the sourhern parr of africa, has had its share of urban problems such as rhe mush· rooming of squarters and low-income urban sertlements. despite efforts to address the substandard living conditions in low-income urban areas, these problems have continued to grow. these living con· diuons are porenrially stressful to rhe residenrs and likely affects their health. the primary aim of the udy wa to examine the complex relationship between communiry-level stressors and interveners and health-related quality of life among residents of low-income neighborhoods in francistown, botswana. u i"" a croa -icctional quantitative design (both descriptive and explanatory) and using primarily cloae-mded interview• with a random sample of residents, this study examined the role of chrome life trnson and environmental quality on overall health status qualiry of life) and the physical, psy· chological and level of independence domains of health. the major hypothesis of the study was that community-levrl stre sor would influence health-related quality of life and that social capital would moderate these relationships. findings indicate that neighborhood quality is a powerful predictor of healrh tatu rhan socioeconomic status and individual life stressors. social capital was also found to he a ificant positive predictor of healrh and also moderator of structural factors. social capital moderated the effects of low environmental quality on level of indrpendence and on physical health outcomn, but nor on psychological and global health outcomes. these findings suggest that as the environment get betttr. stresson are reduced, hence promoting berter health outcomes. the study ends with implication• for social justice, public health and social work practice, and research, focusing mostly on the ~ole of social capital and the environmental quality in predicting health outcomes. spt· cafically • anenhon should be focused on political and civic society's commitment for social justice and poveny alleviation, ~uction of the threat of insecuriry and violence; cultivating social capital and good governance; and improving the health and social environments, especially housing and environ· mental aiutanon to name a few. urban and other uprisings by non-elites that lead to transitions, can disrupt sexual and injection "risk" networks that transmit infectious diseases by changing mixing patterns. they can also weaken urban social networks, their associated protective norms and their informal social control mechanisms which can lead to increased sexual and drug risk behaviors and violence (fullilove ; wallace & wallace , aral , friedman & reid hankins et al ) . for example, the revolution and transition to theocratic rule, and subsequent urban and national conflicts, have been followed by many urban youth in iran engaging in clandestine high-risk sexual and drug behaviors. in palestine, conflicts and restrictions on movement have led to increased fatalities from chronic diseases due to limited access to hospitals and modern medical facilities (union of palestinian medical relief committees); and heroin use and violence-related blood exposure have also increased. social movements "from below" that are rooted both in urban social network dynamics and in underlying patterns of injustice can have both protective and risky effects. for example, the social movements that led to the collapse of the ussr and its dependent governments in other countries-with subsequent increases in sex trade, alcoholism, drug use, tuberculosis, hiv, stis, and mortality in many localities-were based originally on such city-based movements in eastern europe. their impacts on health were mediated by urban social dynamics and structures. some urban social movements have improved health by prevent· ing the spread of hiv, hepatitis and other diseases. examples include movements of (a) gays and lesbians and (b) drug users. these have been rooted in social networks that overlap with risk networks. theories of urban health should include social conflict as a core concept. mechanisms that generate conflicts and the pathways by which conflicts affect health should be a major part of urban health research agendas. p - (c) demographic characteristics of people seen with tuberculosis in lagos state university teaching hospital (lasuth) chest clinic john bako, adewale akeredolu, and wale alabi tuberculosis has become a resurgent public health problem in recent times in the world. because resources are limited, control programmes frequently must target population at greatest risk. the purpose of this study was to study the demographic characteristics of people seen with tuberculosis in lagos state university teaching hospital. a total of patients who have been both radiologically and bacteriologically confirmed tuberculosis patients were used for this study between january and march. ( %) were males, while ( %) were females. notable risk factors among patients with tuberculosis were overcrowding ( . % ), homelessness ( . %) cigarette smoking ( . % ), alcoholism ( . %), non vaccination ( %), secondary contact ( . %) and poor knowledge ( . l 'x,). man· agement history patterns among the patients were herbs ( . 'yo), orthodox medicine ( .h . .l'x.). intervention targeting early-identified groups may be an effective way to reduce the incidence of tuber· culosis. such intervention should focus on health education, modification of life style and improvement of standard of living. p - (c) profiles in urban health in cities of the americas in the countries of the americas, there is an increasing migration of national and international populations to urban centers. this presentation will focus on some of the issues created by this influx of populations, the ways that cities in countries are dealing with them, and the efforts to promote local participation and solutions in management and decision-making. the methodology used to collect this information has been to draw upon and analyze information produced by the mayor's and ministry of health and development offices in each of the cities under consideration. an analysis of the impact of urbanization on health and health determinants will be presented. the information covers issues such as health status by geographic areas within the cities, highlighting issues such as marginality, barriers and physical, economic and cultural constructs and inequities in the delivery of and access to essential services (such as health, education, water, and basic sanitation). issues of governance and citizen participation will be highlighted to provide insight in~o the balance of power and mechanisms for decision-making at the local level. part of the analysis will show the relationship between democratic processes and social participation. public ~olicies will be reviewed to indicate those that are most beneficial in promoting health and overcoming barriers to it, as well as ways of capitalizing on local assets and resources. final~y, evidence of effectiveness of various strategies will be indicated. the presentation will conclude wuh suggesuons for future strategic directions to improve the quality of life and the promotion of health in large urban centers of the americas. introduction: much of the illicit drug in mexico is concentrated in northern border areas. the mile border between the u.s. and mexico is also characterized by migration; the border crossing between tijuana, baja california, mexico and san diego, california, u.s.a. is rep~rt~dl~ the busiest land border crossing in the world. we attempt to describe the migration scene among m ect on drug users (idus) m tijuana and investigate service needs. methods: migration trends were investigated in a cross-sectional study conducted from february to june among idus in tijuana. enrollment criteria included informed consent, being years or older, and having injected drugs within the prior month. subjects were recruited by respondent-dnven sampling and were administered a quantitative survey and serology for hiv, hcv, and syphilis. logistic regression was used to compare idus who had migrated to the u.s. versus those who had not. results: of idus enrolled, % were male and median age and age at first injection were and , respectively. drug combinations injected most frequently in the past months were heroin ( % and crystal methamphetamine mixed with heroin ( %). of those enrolled, responded to quesnons on migration and drug treatment and were included in this analysis. although % had resided in tijuana for at least years, % of users were born outside of baja california. working outside of mexico was common, with % working abroad in the last years ( % in u.s.), and % in the past year. in the last months, % of idus had crossed the border to the u.s., with % crossing at least once per month. those working outside of mexico in the past year were less likely to have ever received substance abuse treatment, [ % vs. %, or . , ] and were marginally less likely to have received drug treatment in the past months [ % vs. %, or . , % ci ( . - . )]. drug use patterns, age and gender did not differ between migrants and non-migrants, although migrants were more likely to report being in need of substance abuse treatment ( % vs. %, respectively). conclusions: migration is common among idus in tijuana. maintaining drug treatment regimens and determining how to best target education and services to a highly mobile population pose challenges to officials on both sides of the border. these data underscore the need to develop coordinated binational prevention and treatment efforts. introduction: despite the expanding literature on the important role public policy plays in influencing the broader determinants of the public\'s health, profound differences exist among jurisdictions in rhe attention placed upon such activities. we take an international perspective on health by examining rhe d?minant public _health paradigms of canada, usa, uk, and sweden and exploring how these paradigms shape public health practice. _method: we carefully analyze governmental and public health agencies documents to discern ~he dommant para~igms driving public health approaches and practices. we also consider the unique paht · cal and economic contexts within each nation and consider how these contexts drive public health pahcy and approaches. . . ~u~: the canadian and usa public health communities -with some exceptions --focus upon m~ividuahzed approaches to risk management. in contrast, the uk and swedish public health scenes are oriented toward broader approaches to health determinants. we find that the extent to which govern· ments, public health agencies and public health workers concern themselves with public policy approaches £<_> ~ddress ~ro.ad~r .determinants of health depends upon the particular health parad'.~ adhered. ~o withm each urisd ctton. and whether a paradigm is adopted depends upon the ideologi~a and pol~ncal context of each nation. nations such as sweden that have a long tradition of public policies promonng social jus~ce an~ equity are naturally receptive to evolving population health concepts. '[he usa represen~ a ~bey en~ro~~t where such is~ues are clear!~ subordinate. ., our findings mdicate that there s a strong political component that influences pubh ~ealth a~proaches and practi~ within the jurisdictions examined. the implications are that those seek· m~ to raise the broader detennmants of the public's health should work in coalition to raise these issues with non-health organizations and age · ca d d th · - badrgrollnd: in developed countries, social inequalities in health have endured or even worsened comparatively throughout different social groups since the s. in france, a country where access to medical and surgical care is theoretically affordable for everyone, health inequalities are among the high· est in western europe. in developing countries, health and access to care have remained critical issues. in madagascar, poverty has even increased in recent years, since the country wenr through political crisis and structural adjustment policies. objectives. we aimed to estimate and compare the impact of socio· economic status but also psychosocial characteristics (social integration, health beliefs, expectations and representation, and psychological characteristics) on the risk of having forgone healthcare in these dif· fercnt contexts. methods: population surveys conducted among random samples of households in some under· served paris neighbourhoods (n= ) and in the whole antananarivo city (n= ) in , using a common individual questionnaire in french and malagasy. reslllts: as expected, the impact of socioeconomic status is stronger in antananarivo than in paris. but, after making adjustments for numerous individual socio-economic and health characteristics, we observed in both cities a higher (and statically significant) occurrence of reponed forgone healthcare among people who have experienced childhood and/or adulthood difficulties (with relative risks up to and .s respectively in paris and antananarivo) and who complained about unhealthy living conditions. in paris, it is also correlated with a lack of trust in health services. coneluions: aside from purely financial hurdles, other individual factors play a role in the non-use of healthcare services. health insurance or free healthcare seems to be necessary hut not sufficienr to achieve an equitable access to care. therefore, health policies must not only focus on the reduction of the financial barriers to healthcare, but also must be supplemented by programmes (e.g. outreach care ser· vices, health education, health promotion programmes) and discretionary local policies tailored to the needs of those with poor health concern .. acknowledgments. this project was supported by the mal>io project and the national institute of statistics (instat) in madagascar, and hy the development research institute (ird) and the avenir programme of the national institute of health and medical research (inserm) in france. for the cities of developing countries, poverty is often described in terms of the living standard~ of slum populations, and there is good reason to believe that the health risks facing these populations are even greater, in some instances, than those facing rural villagers. yet much remains to be learned ahour the connections between urban poverty and health. it is not known what percentage of all urban poor live in slums, that is, in communities of concentrated poverty; neither is it known what proportion of slum residents are, in fact, poor. funhermore, no quantitative accounting is yet available that would sep· arare the health risks of slum life into those due to a househoid•s own poverty and those stemminic from poveny in the surrounding neighborhood. if urban health interventions are to be effectively targeted in developing countries, substantial progress must be made in addressing these cenrral issues. this paper examines poverty and children's health and survival using two large surveys, one a demographic and health survey fielded in urban egypt (with an oversampling of slums) and the other a survey of the slums of allahabad, india. using multivariate statistical methods. we find, in both settings: ( substan· rial evidence of living standards heterogeneity within the slums; ( strong evidence indicating that household-level poverty is an imponant influence on health; and ( ) staristically significant (though less strong) evidence that with household living standards held constant, neighborhood levels of poverty adversely affect health. the paper doses with a discussion of the implications of these findings for the targeting of health and poverty program interventions. p - (a) urban environment and the changing epidemiological surfacr. the cardiovascular ~ &om dorin, nigeria the emergence of cardiovascular diseases had been explained through the concomitants o_f the demographic transition wherein the prevalent causes of morbidity and monality ~hangr pr~mmant infectious diseases to diseases of lifestyle or chronic disease (see deck, ) . a ma or frustration m the v poster sessions case of cvd is its multifactural nature. it is acknowledged that the environment, however defined is the d · f · t' b tween agents and hosts such that chronic disease pathogenesis also reqmre a me an o mterac ion e . spatio-temporal coincidence of these two parties. what is not clear is which among ~ever~( potennal fac· · h b pace exacerbate cvd risk more· and to what extent does the ep dem olog cal trans · tors m t e ur an s ' . . . . tion h othesis relevant in the explanation of urban disease outlook even the developmg cities like nigeri~: thesis paper explorer these within a traditional city in nigeria. . . . the data for the study were obtained from two tertiary level hospitals m the metropolis for years ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) . the data contain reported cases of cvd in the two facilities for the period. adopting a series of parametric and non-parametric statistics, we draw inferences between the observed cases of cvds and various demographic and locational variables of the patients. findings: about % of rhe cases occurred in years ( ) ( ) ( ) coinciding with the last year of military rule with great instability. . % occurred among male. . % also occurred among people aged - years. these are groups who are also likely to engage in most stressful life patterns. ~e study also shows that % of all cases occurred in the frontier wards with minor city areas also havmg their •fair' share. our result conformed with many empirical observation on the elusive nature of causation of cvd. this multifactoral nature had precluded the production of a map of hypertension that would be consistent with ideas of spatial prediction. cvd -cardiovascular diseases. mumbai is the commercial capital of india. as the hub of a rapidly transiting economy, mumbai provides an interesting case study into the health of urban populations in a developing country. with high-rise multimillion-dollar construction projects and crowded slums next to each other, mumbai presents a con· trast in development. there are a host of hi-tech hospitals which provide high quality care to the many who can afford it (including many westerners eager to jump the queue in their healthcare systems-'medical tour· ism'), at the same time there is a overcrowded and strained public healthcare system for those who cannot afford to pay. voluntary organizations are engaged in service provision as well as advocacy. the paper will outline role of the voluntary sector in the context of the development of the healthcare system in mumbai. mumbai has distinct upper, middle and lower economic classes, and the health needs and problems of all three have similarities and differences. these will be showcased, and the response of the healthcare system to these will be documented. a rising hiv prevalence rate, among the highest in india, is a challenge to the mumbai public healthcare system. the role of the voluntary sector in service provision, advocacy, and empowerment of local populations with regards to urban health has been paramount. the emergence of the voluntary sector as a major player in the puzzle of urban mumbai health, and it being visualized as voices of civil society or communiry representatives has advantages as well as pitfalls. this paper will be a unique attempt at examining urban health in india as a complex web of players. the influence of everyday socio·polirical-cultural and economic reality of the urban mumbai population will be a cross cutting theme in the analysis. the paper will thus help in filling a critical void in this context. the paper will thus map out issues of social justice, gender, equiry, effect of environment, through the lens of the role of the voluntary sector to construct a quilt of the realiry of healthcare in mumbai. the successes and failures of a long tradi· tion of the active advocacy and participation of the voluntary sector in trying to achieve social justice in the urban mumbai community will be analyzed. this will help in a better understanding of global urban health, and m how the voluntary sector/ngos fir into the larger picture. ba~und: o~er. half _of n~irobi's . million inhabitants live in illegal informal settlements that compose yo of the city s res dent al land area. the majority of slum residents lack access to proper san· iranon and a clean and adequate water supply. this research was designed to gain a clearer understand· mg of what kappr · · · h f . . opnate samtanon means or the urban poor, to determine the linkages between gender, hvehhoods, and access to water and sanitation, and to assess the ability of community sanitation blocks to meet water and sanitation needs in urban areas. m~tbojs_: _a household survey, gender specific focus groups and key informant interviews were conducted m maih saba, a peri-urban informal settlement. qualitative and quantitative research tools were u~ to asses~ the impact and effectiveness of community sanitation blocks in two informal settlements. results ropna e samtarmn me u es not only safe and clean latrines, but also provision ° adequate drainage and access to water supply for cleaning of clothes and homes. safety and cleanliness poster sessions v were priorities for women in latrines. levels of poverty within the informal settlements were identified and access to water and sanitation services improved with increased income. environmental health problems related to inadequate water and sanitation remain a problem for all residents. community sanitation blocks have improved the overall local environment and usage is far greater than envisioned in the design phase. women and children use the blocks less than men. this is a result of financial, social, and safety constraints. the results highlight the importance a need to expand participatory approaches for the design of water and sanitation interventions for the urban poor. plans need to recognize "appropriate sanitation" goes beyond provision of latrines and gender and socioeconomic differences must be taken into account. lessons and resources from pilot projects must be learned from, shared and leveraged so that solutions can be scaled up. underlying all the challenges facing improving water and sanitation for the urban poor are issues of land tenure. p - (c) integrating tqm (total quality management), good governance and social mobilization principles in health promotion leadership training programmes for new urban settings in countries/ areas: the prolead experience susan mercado, faren abdelaziz, and dorjursen bayarsaikhan introduction: globalization and urbanization have resulted in "new urban settings" characterized by a radical process of change with positive and negative effects, increased inequities, greater environmental impacts, expanding metropolitan areas and fast-growing slums and vulnerable populations. the key role of municipal health governance in mitigating and modulating these processes cannot be overemphasized. new and more effective ways of working with a wide variety of stakeholders is an underpinning theme for good governance in new urban settings. in relation to this, organizing and sustaining infrastructure and financing to promote health in cities through better governance is of paramount importance. there is a wealth of information on how health promotion can be enhanced in cities. despite this, appropriate capacity building programmes to enable municipal players to effectively respond to the challenges and impacts on health of globalization, urbanization and increasing inequity in new urban settings are deficient. the who kobe centre, (funded by the kobe group( and in collaboration with regional offices (emro, searo, wpro) with initial support from the japan voluntary contribution, developed a health promotion leadership training programme called "prolead" that focuses on new and autonomous structures and sustainable financing for health promotion in the context of new urban settings. methodology: country and/or city-level teams from areas, (china, fiji, india, japan, lebanon, malaysia, mongolia, oman, philippines, republic of korea, tonga and viet nam) worked on projects to advance health promotion infrastructure and financing in their areas over a month period. tools were provided to integrate principles of total quality management, good governance and social mobili .ation. results: six countries/areas have commenced projects on earmarking of tobacco and alcohol taxes for health, moblization of sports and arts organizations, integration of health promotion and social health insurance, organizational reforms, training in advocacy and lobbying, private sector and corporate mobilization and community mobilization. results from the other six areas will be reported in ..;obcr. conclusions: total quality management, good governance and social mobilization principles and skills are useful and relevant for helping municipal teams focus on strategic interventions to address complex and overwhelming determinants of health at the municipal level. the prolead training programmes hopes to inform other processes for building health promotion leadership capacity for new urban settings. the impact of city living and urbanization on the health of citizens in developing countries has received increasing attention in recent years. urban areas contribute largely to national economies. however, rapid and unplanned urban growth is often associated with poverty, environmental degradation and population demands that outstrip service capacity which conditions place human health at risk. local and national governments as well as multi national organizations are all grappling with the challenges of urbanization. with limited data and information available, urban health characteristics, including the types, quantities, locations and sources in kampala, are largely unknown. moreover, there is n? basis for assessing the impact of the resultant initiatives to improve health ~onditions amo~g ~o": ": um ties settled in unplanned areas. since urban areas are more than the aggregation ?f ~?pie w~th md_ v dual risk factors and health care needs, this paper argues that factors beyond the md v dual, mcludmg the poster sessions v · i d h · i · ment and systems of health and social services are determinants of the health soc a an p ys ca environ . of urban populations. however, as part of an ongoing study? ~s pape~ .addresses the basic concerns of urban health in kampala city. while applying the "urban hvmg conditions and the urban heal~ pen· alty" frameworks, this paper use aggregated urban health d~ta t~ explore the role of place an~ st tu· tions in shaping health and well-being of the population m kampala by understanding how characteristics of the urban environment and specific features of the city are causally related to health of invisible and forgotten urban poor population: results i~dica~e that a .range o~ urb~n he~l~h hazards m the city of kampala include substandard housing, crowdmg, mdoor air poll.ut on, msuff c ent a~d con· taminated water, inadequate sanitation and solid waste management services, vector borne .diseases, industrial waste increased motor vehicle traffic among others. the impact of these on the envtronment and community.health are mutually reinforcing. arising out of the withdra"'.al of city pl~nning systems and service delivery systems or just planning failure, thousands of people part cularl~ low-mc~me groups have been pushed to the most undesirable sections of the city where they are faced with ~ va_r ety ~f envj· ronmental insults. the number of initiatives to improve urban health is, however, growing mvolvjng the interaction of many sectors (health, environment, housing, energy, transportation and urban planning) and stakeholders (local government, non governmental organizations, aid donors and local community groups). key words: urban health governance, health risks, kampala. introduction: the viability of urban communities is dependent upon reliable and affordable mass transit. in particular, subway systems play an especially important role in the mass transit network, since they provide service to vast numbers of ridersseven of the subway systems worldwide report over one billion passenger rides each year. surprisingly, given the large number of people potentially affected, very little is known about the health and safety hazards that could affect both passengers and transit workers; these include physical (e.g., noise, vibration, accidents, electrified sources, temperature extremes), biological (e.g., transmission of infectious diseases, either through person-to-person spread or vector-borne, for example, through rodents), chemical (e.g., exposure to toxic and irritant chemicals and metals, gas emissions, fumes), electro-magnetic radiation, and psychosocial (e.g., violence, workstress). more recently, we need to consider the threat of terrorism, which could take the form of a mass casualty event (e.g., resulting from conventional incendiary devices), radiological attack (e.g., "dirty bomb"), chemical terrorist attack (e.g., sarin gas), or bioterrorist attack (e.g., weapons grade anthrax). given the large number of riders and workers potentially at risk, the public health implications are considerable. methods: to assess the hazards associated with subways, a structured review of the (english) litera· ture was conducted. ruults: based on our review, non-violent crime, followed by accidents, and violent crimes are most prevalent. compared to all other forms of mass transit, subways present greater health and safety risks. however, the rate of subway associated fatalities is much lower than the fatality rate associated with automobile travel ( . vs. . per million passenger miles), and cities with high subway ridership rates have a % lower per capita rate of transportation related fatalities than low ridership cities ( . versus . annual deaths per , residents). available data also suggest that subway noise levels and levels of air pollutants may exceed recommended levels. . ~: there is a paucity of published research examining the health and safety hazards associated with subways. most of the available data came from government agencies, who rely on passively reported data. research is warranted on this topic for a number of reasons, not only to address important knowled~ gaps, but also because the population at potential risk is large. importantly, from an urban perspecnve, the benefits of mass transit are optimized by high ridership ratesand these could be adversely affu:ted by unsafe conditions and health and safety concerns. veena joshi, jeremy lim. and benjamin chua ~ ~rban health issues have moved beyond infectious diseases and now centre largely on chrome diseases. diabetes is one of the most prevalent non-communicable diseases globally. % of adult ¥ benefit in providing splash pads in more parks. given the high temperature and humidity of london summers, this is an important aspect and asset of parks. interviewed parents claimed to visit city parks anywhere between to days per week. corrduion: given that the vast majority of canadian children are insufficiently active to gain health benefits, identifying effective qualities of local parks, that may support and foster physical activity is essential. strategies to promote activity within children's environments are an important health initiative. the results from this study have implications for city planners and policy makers; parents' opinions of, and use of city parks provides feedback as to the state current local parks, and modifications that should be made for new ones being developed. this study may also provide important feedback for health promoters trying to advocate for physical activity among children. introdt clion: a rapidly increasing proportion of urban dwellers in africa live below the poverty line in overcrowded slums characterized by uncollected garbage, unsafe water, and deficient sanitation and overflowing sewers. this growth of urban poverty challenges the commonly held assumption that urban populations enjoy better health than their rural counterparts. the objectives of this study are (i) to compare the vaccination status, and morbidity and mortality outcomes among children in the slums of nairobi with rural kenya, and (ii) to examine the factors associated with poor child health in the slums. we use data from demographic and health survey representative of all slum settlements in nairobi city carried out in by the african population & health research center. a total of , women aged - from , households were interviewed. our sample consists of , children aged - months. the comparison data are from the kenya demographic and health survey. the outcomes of interest include child vaccination status, morbidity (diarrhea, fever and cough) and mortality, all dichotomized. socioeconomic, environmental, demographic, and behavioral factors, as well as child and mother characteristics, are included in the multivariate analyses. multilevel logistic regression models are used. l'nlimin ry rest lts: about % of children in the slums had diarrhea in the two weeks prior to the survey, compared to % of rural children. these disparities between the urban poor anj the rural residents are also observed for fever ( % against %), cough ( % versus %), infant mortality ( / against / ), and complete vaccination ( % against %). preliminary multivariate results indicate that health service utilization and maternal education have the strongest predictive power on child morbidity and mortality in the slums, and that household wealth has only minor, statistically insignificant effects. conclruion: the superiority of health of urban children, compared with their rural counterparts, masks significant disparities within urban areas. compared to rural residents, children of slum dwellers in nairobi are sicker, are less likely to utilize health services when sick, and stand greater risk to die. our results suggest policies and programs contributing to the attainment of the millennium development goal on child health should pay particular attention to the urban poor. the insignificance of socioeconomic status suggests that poor health outcomes in these communities are compounded by poor environmental sanitation and behavioral factors that could partly be improved through female education and behavior change communication. introduction: historic trade city surat with its industrial and political peace has remained a center of attraction for people from all the comers of india resulting in to pop.ulatio~ explosio~ a~d stressed social and service infrastructure. the topography,dimate and demographic profile of the city s threat to the healthy environment. aim of this analysis is to review the impact of managemt'nt reform on health indicators. method: this paper is an analysis of the changing profile of population, sanitary infr~s~rucrure, local self government management and public health service reform, secondary health stat st cs data, health indicator and process monitoring of years. . . health of entire city and challenge to the management system. plague outbr~ak ( ) was the turning point in the history of civic service management including p~blic ~e~lth service management. ~ocal self government management system was revitalized by reg~lar_ field v s ts o~ al~ cadre~, _decentraltzanon of power and responsibility, equity, regular vigilant momtormg, commumcanon facility, ream_approach and people participation. reform in public health service management was throu_gh stan~~rd zed intervention protocol, innovative intervention, public private partnership, community part c panon, academic and service institute collaboration and research. sanitation service coverage have reached nearer to universal. area covered by safe water supply reached to %( ) from % ( ) and underground drainage to % ( ) from % ( ) the overhauling of the system have reflected on health indicators of vector and water born disease. malaria spr declined to . ( ) from . 'yo(! ) and diarrhea case report declined to ( ) from ( ). except dengue fever in no major disease outbreaks are reported after . city is recipient of international/national awards/ranking for these achievements. the health department have developed an evidence and experience based intervention and monitoring system and protocol for routine as well as disaster situation. the health service and management structure of surat city have emerged as an urban health model for the country. introduction: the center for healthy communities (chc) in the department of family and com· munity medicine at the medical college of wisconsin developed a pilot project to: ) assess the know· ledge, attitudes, and behaviors of female milwaukee public housing residents related to breast cancer; develop culturally and literacy appropriate education and screening modules; ) implement the developed modules; ) evaluate the modules; and ) provide follow-up services. using a community-based participatory research model the chc worked collaboratively with on-site nurse case management to meet these objectives. methods: a "breast health kick off event" was held at four separate milwaukee public housing sites for elderly and disabled adults. female residents were invited to complete a -item breast health survey, designed to accommodate various literacy levels. responses were anonymous and voluntary. the survey asked women about their previous physical exams for breast health, and then presented a series of state· ments about breast cancer to determine any existing myths. the final part gathered information about personal risk for breast cancer, the highest level of education completed, and whether the respondents h;td ever used hormone replacement therapy and/or consumed alcohol. responses were collected for descriptive analysis. results: a total of surveys (representing % of the total female population in the four sites) were completed and analyzed. % reported that they had a physical exam in the previous rwo years. % of respondents indicated they never had been diagnosed with breast cancer. % reported having had a mammogram and % having had a clinical breast exam. those that never had a mammogram reported a fear of what the provider would discover or there were not any current breast problems ro warrant an exam. % agreed that finding breast cancer early could lower the chance of dying of cancer. over % reported that mammograms were helpful in finding cancer. however, % believed that hav· ing a mammogram actually prevents breast cancer. % indicated that mammograms actually cause cancer and % reported that a woman should get a mammogram only if there is breast cancer in her family. conclusion: this survey indicates that current information about the importance of mammograms and clinical breast exams is reaching traditionally underserved women. yet there are still critical oppor· tunities to provide valuable education on breast health. this pilot study can serve as a tool for shaping future studies of health education messages for underserved populations. located in a yourh serv· ~ng agency m downtow~ ottawa, the clinic brings together community partners to provide primary medical care. and dent~i hygiene t? the street youths of ottawa aged - . the primary goal of the project is to provide accessible, coordinated, comprehensive health and dental care to vulnerable adolescents. these efforts respond to the pre-existing body of evidence suggesting that the principle barrier in accessing such care for these youths are feelings of intimidation and vulnerability in the face of a complex healthcare system. the bruyere fhn satellite clinic is located in the basement of a downtown drop-in and brings together a family medicine physician and her residents, a dental hygienist and her nd year students, a nurse practitioner, a chiropodist and public health nurses to provide primary care. the clinic has been extremely busy and well received by the youth. this workshop will demonstrate how five community organizations have come together to meet the needs of high risk youths in ottawa. this presentation will showcase the development of the clinic from its inception through its first year including reaction of the youths, partnerships and lessons learned. it will also focus on its sustainability without continued funding. we hope to have developed a model of service delivery that could be reproduced and sustained in other large cities with faculties of medicine. methods: non-randomized, mixed method design involving a process and impact evaluation. data collection-qualitative-a) semi structured interviews with providers & partners b)focus groups with youth quantitative a)electronic medical records for months records (budget, photos, project information). results: ) successfully built and opened a medicaudental clinic which will celebrate its year anniversary in august. ) over youths have been seen, and we have had over visits. conclusion: ) the clinic will continue to operate beyond the month project funding. ) the health of high risk youth in ottawa will continue to improve due to increased access to medical services. p - (a) health services -for the citizens of bangalore -past, present and future savita sathyagala, girish rao, thandavamurthy shetty, and subhash chandra bangalore city, the capital of karnataka with . million is the th most populous city in india; supporting % of the urban population of karnataka, it is considered as one of the fastest growing cities in india. known as the 'silicon valley of india', bangalore is nearly years old. bangalore city corporation (bmp), is a local self government and has the statutory commitment to provide to the citizens of bangalore: good roads, sanitation, street lighting, safe drinking water apart from other social obligations, cultural development and poverty alleviation activities. providing preventive and promotive heahh services is also a specific component. the objective of this study was to review the planning process with respect to health care services in the period since india independence; the specific research questions being what has been the strategies adopted by the city planners to address to the growing needs of the population amidst the background of the different strategies adopted by the country as a whole. three broad rime ranges have been considered for analysis: the s, s and the s. the salient results are: major area of focus has been on the maternal and child care with activities ranging from day-care to in-patient-care; though the number of institutions have grown from to the current day , their distribution has been far from satisfactory; obtaining support from the india population projects and major upgradarions have been undertaken in terms of infrastructure; over the years, in addition to the dispensaries of modern system of medicine, local traditional systems have also been initiated; the city has partnered with the healthy cities campaign with mixed success; disease surveillance, addressing the problems related to the emerging non-communicable diseases including mental health and road traffic injuries are still in its infancy. isolated attempts have been made to address the risks groups of elderly care and adolescent care. what stands out remarkably amongst the cities achievements is its ability to elicit participation from ngos, cbos and neighbourhood groups. however, the harnessing of this ability into the health sector cannot be said totally successful. the moot question in all the above observed development are: has the city rationally addressed it planning needs? the progress made so far can be considered as stuttered. the analysis and its presentation would identify the key posirive elements in the growth of banglore city and spell a framework for the new public health. introduction: anaemia associated with pregnancy is a major public health problem all over the world. different studies in different parts of india shown prevalence of anaemia between - %. anaemia remains a serious health problem in pregnancy despite of strong action taken by the government of india through national programmes. in the present study we identified th~ social beha~iors, responsible for low compliance of if a tablets consumption in pregnancy at community level and intervention was given with new modified behaviors on trial bases. . in vadodara urban. anganwadies out of were selected from the list by random sampling for tips (trials of improved practices) study. . . participants: pregnant women ( , intervention group+ , control. group) registered m the above anganwadies. study was conducted in to three phases: phase: . formative research and baseline survey (frbs). data was collected from all pregnant women to identify behaviors that are responsible for low compliance of ifa tablets. both qualitative and quantitative data were collected. haemoglobin was estimated of all pregnant women by haemo-cue. phase: . phase of tips. behaviors were identified both social & clinical for low compliance of ifa tablets consumption in pregnancy from frbs and against those, modified behaviors were proposed to pregnant women in the intervention group on trial bases by health education. trial period of weeks was given for trial of new behaviors to pregnant women in the interven· tion group. phase: . in this phase, feedbacks on behaviors tried or not tried were taken from pregnant women in intervention group. haemoglobin estimation was carried out again in all pregnant women. at the end of the study, messages were formulated on the bases of feedbacks from the pregnant women. results: all pregnant women in the intervention group had given positive feedback on new modified behaviors after intervention. mean haemoglobin concentration was higher in intervention group ( . ± . gm%) than control group ( . ± . gm%). ifa tablets compliance was improved in intervention group ( . %) than control group ( . %). conclusion: all pregnant women got benefits after trial of new modified behaviors in the intervention group. messages were formulated from the new modified behaviors, which can be used for longterm strategies for anaemia control in the community. introduction: in order to develop a comprehensive mch handbook for pregnant women and to assess its effect among them, a pilot study was carried out at the maternal and child health training institute (mchti), in dhaka, bangladesh. methods: from mchti a sample of pregnant women was selected and all subjects were women who were attending the first visit of their current pregnancy by using a random sampling method. of the subjects, women were given the mch handbook as case and women were not given the handbook as control. data on pre and post intervention of the handbook from the cases and controls were taken from data recording forms between the st of november and st of october, and data was analysed by using a multilevel analysis approach. this was a hospital-based action (case-control) research, and was applied in order to measure the outcome of pre and post intervention following the introduction of the handbook. data was used to assess the effects of utilisation of the handbook on women's knowledge, practice and utilisation of mch services. results: this study showed that the change of knowledge about antenatal care visits was . % among case mothers. knowledge of danger signs improved . %, breast feeding results . %, vaccination . % and family planning results improved . % among case. results showed some positive changes in women's attitudes among case mothers and study showed the change of practice in antenatal care visits was .u. % in the case. other notable changes were: change of practice in case mother's tetanus toxoid (ti), . %; and family planning . %. in addition, handbook assessment study indicated that most women brought the handbook on subsequent visits ( . %), the handbook was highly utilised (i.e. it was read by . %, filled-in by . %, and was used as a health education tool by . %). most women kept the handbook ( . %) and found it highly useful ( . %) with a high client satisfaction rate of . %. conclusion: pregnant women in the case group had higher knowledge, better practices, and higher utilisation of mch services than mothers in the control groups who used alternative health cards. if the handbook is developed with a focus on utilising a problem-oriented approach and involving the recomendations .of end~users, it is anticipated that the mch handbook will contribute significantly to ensuring the quahry of hfe of women and their children in bangladesh. after several meetmgs to identify the needs of the community, a faso clinic was opened at ncfs. health care professionals from smh joined with developmental and social service workers from ncfs to implement the faso diagnostic process and to provide culturally appropriate after-care. the clinic is unique in that its focus is the high risk urban aboriginal population of toronto. it accepts referrals of not only children and youth, but also of adults. lessons learned: response to the faso clinic at native child and family services has been overwhelming. aboriginal children with f asd are receiving timely diagnosis and interventions. aboriginal youth and adults who have been struggling with poveny, substance abuse, and homelessness are more willing to enter the ncfs centre for diagnosis and treatment. aboriginal infants prenatally exposed to alcohol born at st. michael's hospital or referred by other centres have access to the developmental programs located in both of the partnering agencies. the presentation will describe the clinic's development, and will detail the outcomes described, including interventions unique to the aboriginal culture. p - (c) seeds, soil, and stories: an exploration of community gardening in southeast toronto carolin taran, sarah wakefield, jennifer reynolds, and fiona yeudall introduction: community gardens are increasingly seen as a mechanism for improving nutrition and increasing food security in urban neighbourhoods, but the evidence available to support these claims is limited. in order to begin to address this gap in a way that is respectful of community knowledge and needs, the urban gardening research opportunities workgroup (ugrow) project explored the benefits and potential risks of community gardening in southeast toronto. the project used a community-based research (cbr) model to assess community gardens as a means of improving local health. the research process included interviews, focus groups, and participant observation (documented in field notes). we also directly engaged the community in the research process, through co-learning activities and community events which allowed participants to express their views and comment on emerging results. most of the research was conducted by a community-based research associate, herself a community gardener. key results were derived from these various sources through line-by-line coding of interview transcripts and field note review, an interactive and iterative process which involved both academic and community partners. results: these various data sources all suggest that enhanced health and access to fresh produce are important components of the gardening experience. they also highlight the central importance of empowering and community-building aspects of gardening to gardeners. community gardens were thought to play a role in developing friendships and social support, sharing food and other resources, appreciating cultural diversity, learning together, enhancing local place attachment and stewardship, and mobilizing to solve local problems (both inside and outside the garden). potential challenges to community gardens as a mechanism for communiry development include bureaucratic resistance to gardens, insecure land tenure and access, concerns about soil contamination, and a lack of awareness and under· standing by community members and decision-makers of all kinds. conclusion: the results highlight many health and broader social benefits experienced by commu· nity gardeners. they also point to the need for greater support for community gardening programs, par· ticularly ongoing the ongoing provision of resources and education programs to support gardens in their many roles. this research project is supported by the wellesley central health corporation and the centre for urban health initiatives, a cihr funded centre for research development hased at the univer· sity of toronto. p - (c) developing resiliency in children living in disadvantaged neighbourhoods sarah farrell, lorna weigand, and wayne hammond the traditional idea of targeting risk reduction by focusing on the development of eff~ctive coping strategies and educational programs has merit in light of the research reportmg_ that_ ~ lupl.e forms of problem behaviour consistently appear to be predicted by increasing exposure to den_uf able risk factors. as a result, many of the disadvantaged child and youth studies have focused on trymg to better _unde.r· stand the multiple risk factors that increase the likelihood of the development of at nsk behaviour m ch ldren/youth and the potential implications for prevention. this in turn has led t_o. the conclus on that community and health programs need to focus on risk reduction by helpm~ md v duals develop more effective coping strategies and a better understanding of the limitations of cenam pathologies, problematic v poster sessions coping behaviours and risk factors potentially inheren~ in high needs co~unities. ~owever, another ai:ea of research has proposed that preventative interventions should cons de~ .~rotecnve fa~ors alo~~ with reducing risk factors. as opposed to just emphasizing problems, vulnerab ht es, and deficits, a res liencybased perspective holds the belief that children, youth and their families. have strengths, reso~ce.s and the ability to cope with significant adversity in ways that are not only effective, but tend to result m mcreased ability to constructively respond to future adversity. with this in mind, a participatory research project sponsored by the united way of greater toronto was initiated to evaluate and determine the resiliency profiles of children - years (n = ) of recent immigrant families living in significantly disadvantaged communities in the toronto area. the presentation will provide an overview of the identified protective factors (both intrinsic and extrinsic) and resiliency profiles in an aggregated format as well as a summary of how the children and their parents interpreted and explained these strength-based results. as part of the focus groups, current community programs and services were examined by the participants as to what might be best practices for supporting the development and maintaining of resiliency in children, families and communities. it was proposed that the community model of assessing resiliency and protective factors as well as proposed best strength-based practice could serve as a guide for all in the community sector who provide services and programs to those in disadvantaged neighbourhoods. p - (c) naloxone by prescription in san francisco, ca and new york, ny emalie huriaux the harm reduction coalition's overdose project works to reduce the number of fatal overdoses to zero. located in new york, ny and san francisco, ca, the overdose project provides overdose education for social service providers, single-room occupancy hotel (sro) residents, and syringe exchange participants. the project also conducts an innovative naloxone prescription program, providing naloxone, an opiate antagonist traditionally administered by paramedics to temporarily reverse the effects of opiate overdose, to injection drug users (idus). we will describe how naloxone distribution became a reality in new york and san francisco, how the project works, and our results. the naloxone prescription program utilizes multiple models to reach idus, including sro-and street-based trainings, and office-based trainings at syringe exchange sites. trainings include information on overdose prevention, recognition, and response. a clinician conducts a medical intake with participants and provides them with pre-filled units of naloxone. in new york, funding was initially provided by tides foundation. new york city council provides current funding. new york department of mental health and hygiene provides program oversight. while the new york project was initiated in june , over half the trainings have been since march . in san francisco, california endowment, tides foundation, and san francisco department of public health (sfdph) provide funding. in addition, sfdph purchases naloxone and provides clinicians who conduct medical intakes with participants. trainings have been conducted since november . to date, nearly individuals have been trained and provided with naloxone. approximately of them have returned for refills and reported that they used naloxone to reverse an opiate-related overdose. limited episodes of adverse effects have been reported, including vomiting, seizure, and "loss of friendship." in new york, individuals have been trained and provided with naloxone. over overdose reversals have been reported. over half of the participants in new york have been trained in the south bronx, the area of new york with the highest rate of overdose fatalities. in san francisco, individuals have been trained and provided with naloxone. over overdose reversals have been reported. the majority of the participants in san francisco have been trained in the tenderloin, th street corridor, and mission, areas with the highest rates of overdose fatalities. the experience of the overdose project in both cities indicates that providing idus low-threshold access to naloxone and overdose information is a cost-effective, efficient, and safe intervention to prevent accidental death in this population. p - (c) successful strategies to regulate nuisance liquor stores using community mobilization, law enforcement, city council, merchants and researchers tahra goraya presenta~ion _will discuss ~uccessful environmental and public policy strategies employed in one southen: cahf?rmna commumty to remedy problems associated with nuisance liquor stores. participants ~ be given tools to understand the importance of utilizing various substance abuse prevention str~tegi~ to change local policies and the importance of involving various sectors in the community to a~_ st with and advocate for community-wide policy changes. recent policy successes from the commultles of pa~ad~na and altad~na will highlight the collaborative process by which the community mobilized resulnng m several ordmances, how local law enforcement was given more authority to monitor poster sessions v nonconforming liquor stores, how collaborative efforts with liquor store owners helped to remove high alcohol content alcohol products from their establishments and how a community-based organiz,uion worked with local legislators to introduce statewide legislation regarding the regulation of nuisance liquor outlets. p - (c) "dialogue on sex and life": a reliable health promotion tool among street-involved youth beth hayhoe and tracey methven introduction: street involved youth are a marginalized population that participate in extremely risky behaviours and have multiple health issues. unfortunately, because of previous abuses and negative experiences, they also have an extreme distrust of the adults who could help them. in , toronto public health granted funding to a non governmental, nor for profit drop-in centre for street youth aged - , to educate them about how to decrease rhe risk of acquiring hiv. since then the funding has been renewed yearly and the program has evolved as needed in order to target the maximum number of youth and provide them with vital information in a candid and enjoyable atmosphere. methods: using a retrospective analysis of the six years of data gathered from the "dialogue on sex and life" program, the researchers examined the number of youth involved, the kinds of things discussed, and the number of youth trained as peer leaders. also reviewed, was written feedback from the weekly logs, and anecdotal outcomes noted by the facilitators and other staff in the organization. results: over the five year period of this program, many of youth have participated in one hour sessions of candid discussion regarding a wide range of topics including sexual health, drug use, harm reduction, relationship issues, parenting, street culture, safety and life skills. many were new youth who had not participated in the program before and were often new to the street. some of the youth were given specific training regarding facilitation skills, sexual anatomy and physiology, birth control, sexually transmitted infections, hiv, substance use/abuse, harm reduction, relationships and discussion of their next steps/future plans following completion of the training. feedback has been overwhelmingly positive and stories of life changing decisions have been reported. conclusion: clearly, this program is a successful tool to reach street involved youth who may otherwise be wary of adults and their beliefs. based on data from the evaluation, recommendations have been made to public health to expand the funding and the training for peer leaders in order ro target between - new youth per year, increase the total numbers of youth reached and to increase the level of knowledge among the peer leaders. p - (c) access to identification and services jane kali replacing identification has become increasingly more complex as rhe government identification issuing offices introduce new requirements rhar create significant barriers for homeless people to replace their id. new forms of identification have also been introduced that art' not accessible to homekss peoplt-(e.g. the permanent resident card). ar rhe same time, many service providers continue to require identifi· cation ro access supports such as income, housing, food, health care, employment and employmt·nt training programs. street health, as well as a number of other agencies and community health centres, h, , been assisting with identification replacement for homeless peoplt· for a number of years. the rnrrt·nr challenges inherent within new replacement requirements, as well as the introduction of new forn ' of identification, have resulted in further barriers homeless people encounter when rrring to access t:ssential services. street health has been highlighting these issues to government identification issuing offices, as well as policy makers, in an effort to ensure rhar people who are homeless and marginalized have ac'ess to needed essential services. bandar is a somali word for •·a safe place." the bandar research project is the product of the regent park community health centre. the research looks ar the increasing number of somali and afri· can men in the homeless and precariously house population in the inner city core of down~own toronto. in the first phase of the pilot project, a needs assessment was conducted to dennfy barners and issues faced by rhe somali and other african men who are homeless and have add cr ns issues. th_e second phase of rhe research project was to identify long rerm resources and service delivery mechamsms that v poster sessions would enhance the abiity of this population to better access detox, treatment, and post treatment ser· vices. the final phase of the project was to facilitate the development of a conceptual model of seamless continual services and supports from the streets to detox to treatment to long term rehabilitation to housing. "between the pestle and mortar" -safe place. p - (c) successful methods for studying transient populations while improving public health beth hayhoe, ruth ewert, eileen mcmahon, and dan jang introduction: street youth are a group that do not regularly access healthcare because of their mis· trust of adults. when they do access health care, it is usually for issues severe enough for hospitalization or for episodic care in community clinics. health promotion and illness prevention is rarely a part of their thinking. thus, standard public health measures implemented in a more stable population do not work in this group. for example, pap tests, which have dearly been shown to decrease prevalence of cer· vical cancer, are rarely done and when they are, rarely followed up. methods to meet the health care needs and increase the health of this population are frequently being sought. methods: a drop-in centre for street youth in canada has participated in several studies investigating sexual health in both men and women. we required the sponsoring agencies to pay the youth for their rime, even though the testing they were undergoing was necessary according to public health stan· dards. we surmised that this would increase both initial participation and return. results: many results requiring intervention have been detected. given the transient nature of this population, return rates have been encouraging so far. conclusion: it seems evident that even a small incentive for this population increases participation in needed health examinations and studies. it is possible that matching the initial and follow-up incentives would increase the return rate even further. the fact that the youth were recruited on site, and not from any external advertising, indicates that studies done where youth trust the staff, are more likely to be successful. the presentation will share the results of the "empowering stroke prevention project" which incor· porated self-help mutual aids strategies as a health promotion methodology. the presentation will include project's theoretical basis, methodology, outcomes and evaluation results. self-help methodology has proven successful in consumer involvement and behaviour modification in "at risk," "marginalized" settings. self-help is a process of learning with and from each other which provides participants oppor· tunities for support in dealing with a problem, issue, condition or need. self-help groups are mechanisms for the participants to investigate existing solutions and discover alternatives, empowering themselves in this process. learning dynamic in self-help groups is similar to that of cooperative learning and peertraining, has proven successful, effective and efficient (haller et al, ) . the mutual support provided by participation in these groups is documented as contributory factor in the improved health of those involved. cognizant of the above theoretical basis, in the self-help resource centre initiated the "empowering stroke prevention project." the project was implemented after the input from health organizations, a scan of more than resources and an in-depth analysis of risk-factor-specific stroke prevention materials indicated the need for such a program. the project objectives were:• to develop a holistic and empowering health promotion model for stroke prevention that incorporates selfhelp and peer support strategies. • to develop educational materials that place modifiable risk factors and lifestyle information in a relevant context that validates project participants' life experiences and perspectives.• to educate members of at-risk communities about the modifiable risk factors associated with stroke, and promote healthy living. to achieve the above, a diverse group of community members were engaged as "co-editors" in the development of stroke prevention education materials which reflected and validated their life experiences. these community members received training to become lay health promoters (trained volunteer peer facilitators). in collaboration with local health organizations, these trained lay health promoters were then supported in organizing their own community-based stroke prevention activities. in addition, an educational booklet written in plain language, entitled healthy ways to prevent stroke: a guide for you, and a companion guide called healthy ways to pre· vent stroke: a facilitator's guide were produced. the presentation will include the results of a tw<>tiered evaluation of the program methodology, educational materials and the use of the materials beyond the life of the project. this poster presentation will focus on the development and structure of an innovative street outreach service that assists individuals who struggle mental illness/addictions and are experiencing homelessness. the mental health/outreach team at public health and community services (phcs) of hamilton, ontario assists individuals in reconnecting with health and social services. each worker brings to the ream his or her own skills-set, rendering it extremely effective at addressing the multidimensional and complex needs of clients. using a capacity building framework, each ream member is employed under a service contract between public health and community services and a local grassroots agency. there are public health nurses (phn), two of whom run a street health centre and one of canada's oldest and most successful needle exchange programs, mental health workers, housing specialists, a harm reduction worker, youth workers, and a united church minister, to name a few. a community advisory board, composed of consumers and professionals, advises the program quarterly. the program is featured on raising the roors 'shared learnings on homelessness' website at www.sharedlearnings.ca. through our poster presentation participants will learn how to create effective partnerships between government and grassroots agencies using a capacity building model that builds on existing programs. this study aims to assess the effects of broadcasting a series of documentary and drama videos, intended to provide information about the bc healthguide program in farsi, on the awareness about and the patterns of the service usage among farsi-speaking communities in the greater vancouver area. the major goals of the present study were twofold; ( ) to compare two methods of communications (direct vs. indirect messages) on the attitudes and perceptions of the viewers regarding the credibility of messengers and the relevance of the information provided in the videos, and ( ) to compare and contrast the impact of providing health information (i.e., the produced videos) via local tvs with the same materials when presented in group sessions (using vcr) on participants' attitudes and perceptions cowards the bc healrhguide services. results: through a telephone survey, farsi-speaking adults were interviewed in november and december . the preliminary findings show that % of the participants had seen the aired videos, from which, % watched at least one of the 'drama' clips, % watched only 'documentary' clip, and % watched both types of video. in addition, % of the respondents claimed that they were aware about the program before watching the aired videos, while % said they leaned about the services only after watching the videos. from this group, % said they called the bchg for their own or their "hildren's health problems in the past month. % also indicated that they would use the services in the future whenever it would be needed. % considered the videos as "very good" and thought they rnuld deliver relevant messages and % expressed their wish to increase the variety of subjects (produ\:e more videos) and increase the frequency of video dips. conclusion: the results of this study will assist public health specialists in bc who want to choose the best medium for disseminating information and apply communication interventions in multi\:ultural communities. introduction: many theorists and practitioners in community-based research (cbr) and knowledge transfer (kt) strongly advocate for involvement of potential users of research in the development of research projects, yet few examples of such involvement exist for urban workplace health interventions. we describe the process of developing a collaborative research program. methods: four different sets of stakeholders were identified as potential contributors to and users of the research: workplace health policy makers, employers, trade unions, and health and safety associations. representatives of these stakeholders formed an advisory committee which met quarterly. over the month research development period, an additional meetings were held between resc:ar~h~rs and stakeholders. in keeping with participant observation approaches, field notes of group and md v ~ ual meetings were kept by the two co-authors. emails and telephone calls were also documented. qu~h tative approaches to textual analysis were used, with particular attention paid to collaborattve v poster sessions relationships established (as per cbr), indicators of stakeholders' knowledge utilization (as per kt), and transformations of the proposed research (as per cbr). results: despite initial strong differences of opinion both among stakeho~ders .an~ between stakeholders and researchers, goodwill was noted among all involved. acts of rec~proc ty included mu.rual sharing of assessment tools, guidance on data utilization to stakeho~der orga~ zat ns, and suggestions on workplace recruitment to researchers. stakeholders demonstrated mcreases m concep~ual. un~erstand ing of workplace health e.g. they more commonly discussed more complex,. psychosocial md cators of organizational health. stakeholders made instrumental use of shared materials based on research e.g. adapting their consulting model to more sophisticated dat~ analysis. sta~ehol?~rs recogni_zed the strategic use of their alliance with researchers e.g., transformational leadership trainmg as a~ inducement to improve health and safety among small service franchises. stakeholders helped re-define the research questions, dramatically changed the method of recruitment from researcher cold call to stakeholderbased recruitment, and strongly influenced pilot research designs. owing a great deal to the elaborate joint development process, the four collaboratively developed pilot project submissions which were all successfully funded. conclusion: the intensive process of collaborative development of a research program among stakeholders and researchers was not a smooth process and was time consuming. nevertheless, the result of the collaborative process was a set of projects that were more responsive to stakeholder needs, more feasible for implementation, and more broadly applicable to relevant workplace health problems. introduction: environmental groups, municipal public health authorities and, increasingly, the general public are advocating for reductions in pesticide use in urban areas, primarily because of concern around potential adverse health impacts in vulnerable populations. however, limited evidence of the relative merits of different intervention strategies in different contexts exists. in a pilot research project, we sought to explore the options for evaluating pesticide reduction interventions across ontario municipalities. methods: the project team and a multi-stakeholder project advisory committee (pac), generated a list of potential key informants (kl) and an open ended interview guide. thirteen ki from municipal government, industry, health care, and environmental organizations completed face to face or telephone interviews lasting - minutes. in a parallel process, a workshop involving similar representatives and health researchers was held to discuss the role of pesticide exposure monitoring. minutes from pac meetings, field notes taken during ki interviews, and workshop proceedings were synthesized to generate potential evaluation methods and indicators. results: current evaluation activities were limited but all kls supported greater evaluation effons beginning with fuller indicator monitoring. indicators of education and outreach services were imponant for industry representatives changing applicator practices as well as most public health units and environmental organizations. lndictors based on bylaw enforcement were only applicable in the two cities with bylaws, though changing attitudes toward legal approaches were being assessed in many communities. the public health rapid risk factor surveillance system could use historical baseline data to assess changes in community behaviour through reported pesticide uses and practices, though it had limited penetration in immigrant communities not comfortable in english. pesticide sales (economic) data were only available in regional aggregates not useful for city specific change documentation. testing for watercourse or environmental contamination might be helpful, but it is sporadic and expensive. human exposure monitoring was fraught with ethical issues, floor effects from low levels of exposure, and prohibitive costs. clinical episodes of pesticide exposure reported to the regional poison centre (all ages) or the mother risk program (pregnant or breastfeeding women) are likely substantial underestimates that would be need to be supplemented with sentinel practice surveillance. focus on special clinical populations e.g., multiple chemical sensitivity would require additional data collection efforts . . conc~ons: broad support for evaluation and multiple indicators were proposed, though con-s~raints associate~ with access, coverage, sensitivity and feasibility were all raised, demonstrating the difficulty of evaluating such urban primary prevention initiatives. interventionists. an important aim of the youth monitor is to learn more about the health development of children and adolescents and the factors that can influence this development. special attention is paid to emo· tional and behavioural problems. the youth monitor identifies high-risk groups and factors that are associated with health problems. at various stages, the youth monitor chancrs the course of life of a child. the sources of informa· tion and methods of research are different for each age group. the results arc used to generate various kinds of repons: for children and young persons, parents, schools, neighbourhoods, boroughs and the municipality of rotterdam and its environs. any problems can be spotted early, at borough and neigh· bourhood level, based on the type of school or among the young persons and children themselves. together with schools, parents, youngsters and various organisations in the area, the municipal health service aims to really address these problems. on request, an overview is offered of potentially suitable interventions. the authors will present the philosophy, working method, preliminary effects and future developments of this instrument, which serves as the backbone for the rotterdam local youth policy. social workers to be leaders in response to aging urban populations: the practicum partnership program sarah sisco, alissa yarkony, and patricia volland "'" tliu:tion: across the us, . % of those over live in urban areas. these aging urban popu· lations, including the baby boomers, have already begun encounter a range of heahh and mental hcahh conditions. to compound these effects, health and social service delivery fluciuates in cities, whit:h arc increasingly diverse both in their recipients and their systems. common to other disciplines (medicine, nursing, psychology, etc.) the social work profession faces a shortage of workers who are well-equipped to navigate the many systems, services, and requisite care that this vast population requires. in the next two decades, it is projected that nearly , social workers will be required to provide suppon to our older urban populations. social workers must be prepared to be aging-savvy leaders in their field, whether they specialize in gerontology or work across the life span. mllhotu: in , a study conducted at the new york academy of medicine d<> :umcntcd the need for improved synchroniciry in two aspects of social work education, classroom instruction and the field experience. with suppon from the john a. hanford foundation, our team created a pilot proj~"t entitled the practicum pannership program (ppp) in master's level schools of social work, to improvt" aginr exposure in field and classroom content through use of the following: i) community-university partnrr· ships, ) increased, diverse student field rotations, ll infusion of competcn ."}'·drivm coursework, enhancement of field instructors' roles, and ) concentrated student recruitment. we conductt"d a prr· and post-test survey into students' knowledge, skills. and satisfaction. icarlja: surveys of over graduates and field inltnk."tors rcflected increased numlk-n of . rrm:y· univmity panncrships, as well as in students placed in aging agencin for field placements. there wa marked increase in student commitments to an aging specialization. onr year por.t·gradu:nion rcvealrd that % of those surveyed were gainfully employed, with % employed in the field of aginic. by com· bining curricular enhancement with real-world experiences the ppp instilled a broad exposurr for llu· dents who worked with aging populations in multiple urban settings. coltdtuion: increased exposure to a range of levels of practicr, including clinical, policy/ajvocaq, and community-based can potentially improve service delivery for older adulh who live in elfin, and potentially improve national policy. the hanford foundation has now elected to uppon cxpantion of the ppp to schools nationwide (urban and rural) to complement other domntic initiatives to cnhalk"c" holistic services for older adults across the aging spectrum. bodrgnn.ntl: we arc a team of rcscarcbcn and community panncn working tcj c(her to develop an in"itepth understanding of the mental health needs of homeless youth ~ages to ) (using qualiutivc and quantitative methods ' panicipatory rncarch methods). it is readily apparmt that '-neless youth cxpcricnce a range of mental health problems. for youth living on the street, menul illnew may be either a major risk factor for homelessnal or may frequently emcsge in response to coping with rhe multitudinous stressors associated with homclcslllcsi including exposure to violence, prasutt to pamaplte in v poster sessions survival sex and/or drug use. the most frequent psychiatric diagnoses amongst the homeless gencrally include: depression, anxiety and psychosis. . . . the ultimate ob ective of the pr~am of rei:e~ is to ~evelop a plan for intervention to meet the mental health needs of street youth. prior t_o pl~nnmg mtervenbons, .it is necessary to undertake a comprehensive assessment ~f mental health needs m this ~lnerable populanon. thus, the immediate objective of this research study is to undertake a comprehensive assessment of men· tal health needs. . . melbotlology: a mixed methodology triangulating qualitative, participatory acnon and quantitative methods will capture the data related to mental health needs of homeless youth. a purposive sample of approximately - subjecrs. ages to , is currently being ~ted ~participate from the commu.nity agencies covenant house, evergreen centre fo~ srrc;et youth, turning p? ?t and street ~ serv~. youth living on the street or in short -term residennal programs for a mmimum of month pnor to their participation; ages to and able to give infonned consent will be invited to participate in the study. o..tcomes: the expected outcome of this initial survey will be an increased understanding of mental health needs of street youth that will be used to develop effective interventions. it is anticipated that results from this study will contribute to the development of mental health policy, as well as future programs that are relevant to the mental health needs of street youth. note: it is anticipated that preliminary quantitative data ( subjects) and qualitative data will be available for the conference. the authors intend to present the identification of the research focus, the formation of our community-based team, relevance for policy, as well as preliminary results. p - (a) the need for developing a firm health policy for urban informal worken: the case of despite their critical role in producing food for urban in kenya, urban farmers have largely been ignored by government planners and policymakers. their activity is at best dismissed as peripheral eveo, inappropriate retention of peasant culture in cities and at worst illegal and often some-times criminal· ized. urban agriculture is also condemned for its presumed negative health impact. a myth that contin· ues despite proof to the contrary is that malarial mosquitoes breed in maize grown in east african towns. however, potential health risks are insignificant compared with the benefits of urban food production. recent studies too rightly do point to the commercial value of food produced in the urban area while underscoring the importance of urban farming as a survival strategy among the urban poor, especially women-headed households. since the millennium declaration, health has emerged as one of the most serious casualties consequent on the poverty, social exclusion, marginalisation and lack of sustain· able development in africa. hiv/aids epidemic poses an unprecedented challenge, while malaria, tuber· culosis, communicable diseases of childhood all add to the untenable burden. malnutrition underpins much ill-health and is linked to more than per cent of all childhood deaths. kenya's urban poor people ~ace ~ h~ge burde~ of preventable and treatable health problems, measured by any social and bi~ medical md cator, which not only cause unnecessary death and suffering, but also undermine econonuc development and damage the country's social fabric. the burden is in spite of the availability of suitable tools and re:c=hnology for prevention and treatment and is largely rooted in poverty and in weak healah •rstems. this pa~ therefore challenges development planners who perceive a dichotomy instead of con· tmuum between informal and formal urban wage earners in so far as access to health services is con· cemed. it i~ this gap that calls for a need to developing and building sustainable health systems among the urban mformal ~wellers. we recommend a focus on an urban health policy that can build and strengthen the capacity of urban dwellers to access health services that is cost-effective and sustainable. such ~ health poli<=>: must strive for equity for the urban poor, displaced or marginalized; mobilise and effect ~ely use sufficient sustainable resources in order to build secure health systems and services. special anenti_on. should ~ afforded hiv/aids in view of the unprecedented challenge that this epidemic poses to africa s economic and social development and to health services on the continent. methods: a review of the literature led us to construct three simple models and a composite model of exposure to traffic. the data were collected with the help of a daily diary of travel activities using a sample of cyclists who went to or come back from work or study. to calculate the distance, the length of journey, and the number of intersections crossed by a cyclist different geographic information systems (gis) were operated. statistical analysis was used to determine the significance between a measure of exposure on the one hand, and the sociodemographic characteristics of the panicipants or their geographic location on the other hand. restlltj: our results indicate that cyclists were significantly exposed to road accidents, no matter of where they live or what are their sociodemographic characteristics. we also stress the point that the fact of having been involved in a road accident was significantly related to the helmet use, but did not reduce the propensity of the cyclists to expose themselves to the road hazards. condlllion: the efforts of the various authorities as regards road safety should not be directed towards the reduction of the exposure of the vulnerable users, but rather towards the reduction of the dangers to which they could face. keywords: cyclist, daily diary of activities, measures of exposure to traffic, island of montreal. p - (a) intra urban disparities and environmental health: some salient features of nigerian residential neighbourhoods olumuyiwa akinbamijo intra urban disparities and environmental health: some salient features of nigerian residential neighbourhoods abstract urbanization panicularly in nigerian cities, ponends unprecedented crises of grave dimensions. from physical and demographic viewpoints, city growth rates are staggering coupled with gross inabilities to cope with the consequences. environmental and social ills associated with unguarded rapid urbanization characterize nigerian cities and threaten urban existence. this paper repons the findings of a recent study of the relationship between environmental health across inrraurban residential communities of akure, south west nigeria. it discuses the typical urbanization process of nigerian cities and its dynamic spatial-temporal characteristics. physical and socio-demographic attributes as well as the levels and effectiveness of urban infrastructural services are examined across the core residential districts and the elite residential layouts in the town. the incidence rate of cenain environmentally induced tropical diseases across residential neighborhoods and communes is examined. salient environmental variables that are germane to health procurement in the residential districts, incidence of diseases and diseases parasitology, diseases prevention and control were studied. field data were subjected to analysis ranging from the univariate and bivariate analysis. inferential statistics using the chi-square test were done to establish the truthfulness of the guiding hypothesis. given the above, the study affirms that there is strong independence in the studied communities, between the environment and incidence of diseases hence health of residents of the town. this assertion, tested statistically at the district levels revealed that residents of the core districts have very strong independence between the environment and incidences of diseases. the strength of this relationship however thins out towards the city peripheral districts. the study therefore concludes that since most of the city dwellers live in urban deprivation, urban health sensitive policies must be evolved. this is to cater for the urban dwellers who occupy fringe peripheral sites where the extension of facilities often times are illegally done. urban infrastructural facilities and services need be provided as a matter of public good for which there is no exclusive consumption or access even for the poorest of the urban poor. many suffer from low-self esteem, shame and guilt about their drug use. in addition, they often lack suppon or encounter opposition from their panners, family and friends in seeking treatment. these personal barriers are compounded by fragmented addiction, prenatal and social care services, inflexible intake systems and poor communication among sectors. the experience of accessing adequate care between services can be overwhelming and too demanding. the toronto centre for substance use in pregnancy (t-cup) is a unique program developed to minimize barriers by providing kone-stop" comprehensive healthcare. t-cup is a primary care based program located in the department of family medicine at st. joseph\'s health centre, a community teaching hospital in toronto. the interdisciplinary staff provides prenatal and addiction services, case management, as well as care of newborns affected by substance use. regular care plan meetings are held between t-cup, labour and delivery nurses and social workers in the y poster sessions maternity and child care program. t-cup also connects "'.omen with. inpatient treatment programs and community agencies such as breaking the cycle, an on-site counselmg group for pregnant substance users. · f · d d h ith method: retrospective chart review, qualitative patient ~ans action stu ~· an ea care provider surveys are used to determine outcomes. primary outcomes mclude changes m maternal su~tance use, psychosocial status and obstetrical complications (e.g. pre-rupture of membrane, pre-eclampsia, placen· ral abruption and hemorrhage). neonatal measures ~~nsisted of .bir~h pa_rame~ers, length of h~spital st.ay and complications (e.g. feral distress, meconium stammg, resuscitation, aund ce, hypoglycemia, seventy of withdrawal and treatment length). chart review consisted of all t-cup patients who met clinical cri· reria for alcohol or drug dependence and received prenatal and intra-partum care at st. joseph's from october to june . participants in the qualitative study included former and current t-cup patients. provider surveys were distributed on-site and to a local community hospital. raulb: preliminary evaluation has demonstrated positive results. treatment retention and satisfaction rates were high, maternal substance use was markedly reduced and neonatal outcomes have shown to be above those reported in literature. conclusion: this comprehensive, primary care model has shown to be optimal in the management of substance use in pregnancy and for improving neonatal outcomes. future research will focus on how this inexpensive program can be replicated in other health care settings. t-cup may prove to be the optimal model for providing care to pregnant substance users in canada. lntrod ction: cigarette smoking is one of the most serious health problems in taiwan. the prevalence of smoking in is . % in males . % in females aged years and older. although the government of taiwan passed a tobacco hazards control act in , it has not been strongly enforced in many places. therefore, community residents have often reported exposure of second hand smoke. the purpose of the study was to establish a device to build up more smoke-free environments in the city of tainan. methods: unique from traditional intervention studies, the study used a healthy city approach to help build up smoke-free environments. the major concept of the approach is to build up a healthy city platform, including organizing a steering committee, setting up policies and indicators, creating intersectoral collaboration, and increasing community participation. first, more than enthusiastic researchers, experts, governmental officers, city counselors and community leaders in tainan were invited in the healthy city committee. second, smoke-free policies, indicators for smoke-free environments, and mechanisms for inter-departmen· tal inspections were set up. third, community volunteers were recruited and trained for persuading related stakeholders. lastly, both penalties and rewards were used for help build up the environments. raults: aher two-year ( aher two-year ( - execution of the project, the results qualitatively showed that smoke-free environments in tainan were widely accepted and established, including smoke-free schools, smoke-free workpla~es, smoke-free households, smoke-free internet shops, and smoke-free restaurants. smoke~s were. effectively educated not to smoke in public places. community residents including adults and children m the smoke-free communities clearly understand the adverse effects of environmental tobacco smoke and actively participated anti-smoking activities. conclruions: healthy city platform is effective to conquer the barrier of limited anti-smoking rc:sources. nor. only can it enlar:ge community actions for anti-smoking campaigns, but also it can provide par_merships for collaboratjon. by establishing related policies and indicators the effects of smoke· free environments can be susta ·ned a d th · · · ' · n e progression can be monitored m a commuruty. these issues are used ~· oi::c it~ goals, weuha identifies issues that put people's health at risk. presently, team com~u:c: ran ee~tion !earns. (iats) that design integrative solutions ~tesj'°~ g om six to fifteen members. methods in order to establish wo-poster sessions v projects for weuha, the following approach was undertaken: i. a project-polling template was created and sent to all members of the alliance for their input. each member was asked to identify thdr top two population groups, and to suggest a project on which to focus over a - month period for each identified population. . there was a % response to the poll and the top three population groups were identified. data from the toronto community health profile database were utilized to contextualize the information supplied for these populations. a presentation was made to the steering committee and three population-based projects were selected, leaders identified and iats formed. three population-based projects: the population-based projects and health care issues identified are: newcomer prenatal uninsured women; this project will address the challenges faced by providers to a growing number of non-insured prenatal women seeking care. a service model where the barrier of "catchments" is removed to allow enhanced access and improved and co-ordinated service delivery will be pilot-tested. children/obesity/diab etes: using a health promotion model this team will focus on screening, intervention, and promoting healthy lifestyles (physical activity and nutrition) for families as well as for overweight and obese children. seniors health promotion and circle of discharge: this team will develop an early intervention model to assist seniors/family unit/caregivers in accessing information and receiving treatment/care in the community. the circle of discharge initiative will address ways of utilizing community supports to keep seniors in the community and minimize readmissions to acute care facilities. results/expected outcomes: coordinated and enhanced service delivery to identified populations, leading to improved access, improved quality of life, and health care for these targeted populations. introduction: basic human rights are often denied to high-risk populations and people living with hiv/aids. their rights to work and social security, health, privacy, non discrimination, liberty and freedom of movement, marriage and having a family have been compromised due to their sero-positive status and risk of being positive. the spread of hiv/aids has been accelerating due to the lack of general human rights among vulnerable groups. to formulate and implement effective responses needs dialogue and to prevent the epidemic to go underground barriers like stigma need to be overcome. objective: how to reduce the situation of stigma, discrimination and human rights violations experienced by people living with hiv/aids and those who are vulnerable to hiv/aids. methodology and findings: consultation meetings were strm.-rured around presentations, field visits, community meetings and group work to formulate recommendations on how govt and ngos/cbos should move forward based on objective. pakistan being a low prevalence country, the whole sense of compl;u:enc.:y that individuals are not subject to situations of vulnerable to hiv is the major threat to an explosion in th•· epidemic, therefore urgent measures are needed to integrate human rights issues from the very start of the response. the protection and promotion of human rights in an integral component of ;tll responses to the hiv/aids epidemic. it has been recognized that the response to hiv/aios must he multi sectoral and multi faceted, with each group contributing its particular expertise. for this to occur along with other knowlcdg<" more information is required in human rights abuses related to hiv/ aids in a particular scenario. the ~·on sultarion meetings on hiv/aids and human rights were an exemplary effort to achieve the same ohj<..:tivc. recommendations: the need for a comprehensive, integrated and a multi-sectoral appro;u.:h in addressing the issue of hiv/aids was highlighted. the need social, cultural and religious asp•·ct' to he: prominently addressed were identified. it was thought imperative measures even in low prevalence countries. education has a key role to play, there is a need for a code of ethics for media people and h<"alth care providers and violations should be closely monitored and follow up action taken. p - (c) how can community-based funding programs contribute to building community capacity and how can we measure this elusive goal? mary frances maclellan-wright, brenda cantin, mary jane buchanan, and tammy simpson community capacity building is recognized by the public health agency of canada (phac) as an important strategy for improving the overall health of communities by enabling communities to addre~s priority issues such as social and economic determinants of health. in / phac.:, alberta/nwf region's population health fund (phf) supported community-based projects to build community capacity on or across the determinants of health. specifically, this included creating accessible and sup· portive social and physical environments as well as creating tools and processes necessary for healthy policy development and implementation. the objective of this presentation is to highlight how the community capacity building tool, developed by phac ab/nwf region, can demonstrate gains in v poster sessions · · the course of a pror· ect and be used as a reflective tool for project planning and community capacity over . . . . i · a art of their reporting requirements, pro ect sites completed the community caparny eva uanon. s p . . th t i ii i'd d . building tool at the beginning and end of their ~ne-year prorect. e oo ~o ects va an reliable data in the context of community-based health prorects. developed through a vigorous ~nd collabora ve research process, the tool uses plain languag~ to expl~re nine key f~atures o~ commuruty cap~city with 't ch with a section for contextual information, of which also mdude a four-pomt raong ems, ea f fu d · scale. results show an increase in community capacity over the course o the nde prorects. pre and post aggregate data from the one-year projects measure~ statistic.ally si~n~ficant changes for of the scaled items. projects identified key areas of commumty capacity bmldmg that needed strengthemng, such as increasing participation, particularly among people with low incomes; engaging community members in identifying root causes; and linking with community groups. in completing the tool, projects examined root causes of the social and economic determinants of health, thereby exploring social justice issues related to the health of their community. results of the tool also served as a reflec· cion on the process of community capacity building; that is, how the project outcomes were achieved. projects also reported that the tool helped identify gaps and future directions, and was useful as a project planning, needs assessment and evaluation tool. community capacity building is a strategy that can be measured. the community capacity building tool provides a practical means to demonstrate gains in community capacity building. strengthening the elements of community capacity building through community-based funding can serve as building blocks for addressing other community issues. needs of marginalized crack users lorraine barnaby, victoria okazawa, barb panter, alan simpson, and bo yee thom background: the safer crack use coalition of toronto (scuc) was formed in in response to the growing concern for the health and well-being of marginalized crack users. a central concern was the alarm· ing hepatitis c rate ( %) amongst crack smokers and the lack of connection to prevention and health ser· vices. scuc is an innovative grassroots coalition comprised of front-line workers, crack users, researcher! and advocates. despite opposition and without funding, scuc has grown into the largest crack specific harm reduction coalition in canada and developed a nationally recognized sarer crack kit distribution program (involving community-based agencies that provide outreach to users). the success of our coalition derives from our dedication to the issue and from the involvement of those directly affected by crack use. setting: scuc's primary service region is greater toronto, a diverse, large urban centre. much ofour work is done in areas where homeless people, sex trade workers and drug users tend to congregate. recently, scuc has reached out to regional and national stakeholders to provide leadership and education. mandate: our mandate is to advocate for marginalized crack users and support the devdopmentof a com.p.rehensive harm reduction model that addresses the health and social needs facing crack users; and to fac htare the exchange of information between crack users, service providers, researchers, and policy developers across canada. owrview: the proposed workshop will provide participants with an overview of the devdopment of scuc, our current projects (including research, education, direct intervention and consultation), our challenge~ and s~ccesses and the role of community development and advocacy within the coalition. pre-senter~ will consist of community members who have personal crack use experience and front-line work· ers-, sc.uc conducted a community-based research project (toronto crack users perspectives, ) , in w~ich s focus groups with marginalized crack users across toronto were conducted. participants iden· t f ed health and social issues affecti h b · · · d " red . . ng t em, arrsers to needed services, personal strategies, an oue recommendations for improved services. presenters will share the methodology, results and recommen· datmns resulting from the research project. conc/usio": research, field observations and consultations with stakeholders have shown that cradck shmoke~s are at an. increased risk for sexually transmitted infections hiv/aids hepatitis c, tb an ot er serious health issues health · ff, · ' ' · · . · issues a ectmg crack users are due to high risk behavmurs, socio· economic factors, such as homeless d. · · · · d · . . ness, scrsmmat on, unemployment, violence incarceraoons, an soc a so at on, and a lack of comprehe · h i h · ' ns ve ea t and social services targeting crack users. · · sinct · s, owever arge remains a gross underesurnaoon. poster sessions v these are hospital-based reports and many known cases go unreported. however teh case, young age at first intercourse, inconsistent condom use and multiple partnersplace adolescents at high risks for a diverse array of stls, including hiv. about % of female nigerian secondary school students report initiating sexual intercourse before age years. % of nigerian female secondary school students report not using a condom the last time they had sexual intercourse. more than % of urban nigerian teens report inconsistent condom use. methods: adolescents were studied, ages to , from benin city in edo state. the models used were mother-daughter( ), mother -son( ), father -son ( ), and father-daughter( ). the effect of parent-child sexual communicationat baseline on child\'s report of sexual behavior, to months later were studied. greater amounts of sexual risk communication were asociated with markedly fewer episodes of unprotected sexual intercourse, reduced number of sexual partners and fewer episodes of unprotected sexual intercourse. results: this study proved that parents can exert more influence on the sexual knowledge attitudes and practise of their adolescent children through desired practises or rolemodeling, reiterating their values and appropriate monitoring of the adolescents\' behavior. they also stand to provide information about sexuality and various sexual topics. parental-child sexual communication has been found to be particularly influential and has been associated with later onset of sexual initiation among adolescents, less sexual activity, more responsible sexual attitudes including greater condom use, self efficacy and lower self -reported incidence of stis. conclusions: parents need to be trained to relate more effectively with their children/wards about issues related to sex and sexuality. family -based programs to reduce sexual risk-taking need to be developed. there is also the need to carry out cross-ethnicaland cross-cultural studies to identify how parent-child influences on adolescent sexual risk behavior may vary in different regions or countries, especially inthis era of the hiv pandemic. introduction: public health interventions to identify and eliminate health disparities require evidence-based policy and adequate model specification, which includes individuals within a socioecological context, and requires the integration of biosociomedical information. multiple public and private data sources need to be linked to apportion variation in health disparities ro individual risk factors, the health delivery system, and the geosocial environment. multilevel mapping of health disparities furthers the development of evidence-based interventions through the growth of the public health information network (phin-cdc) by linking clinical and population health data. clinical encounter data, administrative hospital data, population socioenvironmental data, and local health policy were examined in a three-level geocoded multilevel model to establish a tracking system for health disparities. nj has a long established political tradition of "home rule" based in elected municipal governments, which are responsible for the well-being of their populations. municipalities are contained within counties as defined by the us census, and health data are linked mostly at the municipality level. marika schwandt community organizers from the ontario coaliti~n again~t pove~, .along ":ith ~edical practitioners who have endorsed the campaign and have been mvolved m prescnbmg special diet needs for ow and odsp recipients, will discuss the raise the rates campaign. the organizati~n has used a special diet needs supplement as a political tool, meeting the urgent needs o.f .poor ~ople m toront~ while raising the issues of poverty as a primary determinant of health and nutrtnous diet as a preventative health mea· sure. health professionals carry the responsibility to ensure that they use all means available to them to improve the health of the individuals that they serve, and to prevent future disease and health conditions. most health practitioners know that those on social assistance are not able to afford nutritious foods or even sufficient amounts of food, but many are not aware of the extra dietary funds that are available aher consideration by a health practitioner. responsible nurse practitioners and physicians cannot, in good conscience, ignore the special needs diet supplement that is available to all recipients of welfare and disabiliry (ow and odsp). a number of toronto physicians have taken the position that all clients can justifiably benefit from vitamins, organic foods and high fiber diets as a preventative health measure. we know that income is one of the greatest predictors of poor health. the special needs diet is a health promotion intervention which will prevent numerous future health conditions, including chronic conditions such as cardiovascular disease, cancer, diabetes and osteoporosis. many communiry health centres and other providers have chosen to hold clinics to allow many patients to get signed up for the supplement at one time. initiated by the ontario coalition against poverty, these clinics have brought together commu· niry organizers, community health centers, health practitioners, and individuals, who believe that poverty is the primary determinant of poor health. we believe that rates must be increased to address the health problems of all people on social assistance, kids, elders, people with hiv/aids -everyone. even in the context of understaffing, it could be considered a priority activity that has potentially important health promotion benefits. many clients can be processed in a two hour clinic. most providers find it a very interesting, rewarding undertaking. in the ontario coalition for social justice found that a toronto family with two adults and two kids receives $ , . this is $ , below the poverty line. p - (c) the health of street youth compared to similar aged youth beth hayhoe and ruth ewert . lntrod~on: street youth are at an age normally associated with good health, but due to their risky ~hav ours and th~ conditions in which they live, they experience health conditions unlike their peer~ an more stable env r~nments. in addition, the majority of street youth have experienced significant physical, sexual ~nd em.ot onal abuse as younger children, directly impacting many of the choices they make around their physical and emotional health. we examined how different their health really is. . , methodl: using a retrospective analysis of the years of data gathered from yonge street mis· ~ • evergreen health centre, the top conditions of youth were examined and compared with national tren~s for similar aged youth. based on knowledge of the risk factors present in the group, rea· sons for the difference were examined. d' ~its: street youth experience more illness than other youth their age and their illnesses can bt . irect t ·~kc~ to the. conditions in which they live. long-term impacts of abus~ contribute to such signif· ~~nt t e t d~slpl air that youth may voluntarily engage in behaviours or lack of self care in the hope at t cir ve~ w perhaps come to a quicker end. concl non: although it has ion b k h th' dy clearly shows d'fi . h g ee~ no~n t at poverty negatively affects health, ~siu be used to make ; erence m t .e health of this particular marginalized population. the infonnanon can relates to th . ecommendatio.ns around public policy that affects children and youth, especially as it e r access to appropriate health care and follow up. p - (cl why do urban children · b gt . tarek hussain an adesh die: how to save our children? the traditional belief that urban child alid. a recent study (dhs d fr r~n are better off than rural children might be no longer v urban migrants are highata th om h c~untn~s i demonstrates that the child survival prospects of rural· er an t ose m their r j · · ·grants. in bangladesh, currently million ~r~ ~ gm and lower than those of urban non-idi million. health of the urban ~ p~e are hvmg m urban area and by the year , it would be so the popu at on s a key a eals that urban poor have the worse h h . concern. recent study on the urban poor rev ea t situation than the nation as a whole. this study shows that infant poster sessions v mortality among the urban poor as per thousand, which are above the rural and national level estimates. the mortality levels of the dhaka poor are well above those of the rest of the city's population but much of the difference in death rates is explained by the experience of children, especially infants. analyzing demographic surveillance data from a large zone of the city containing all sectors of the population, research showed that the one-fifth of the households with the least possessions exhibited u child mortality almost three times as high as that recorded by the rest of the population. why children die in bangladesh? because their parents are too poor to provide them with enough food, clean water and other basic needs to help them avoid infection and recover from illness. researchers believed that girls are more at risk than boys, as mothers regularly feed boys first. this reflects the different value placed on girls and boys, as well as resources which may not stretch far enough to provide for everyone. many studies show that housing conditions such as household construction materials and access to safe drinking water and hygienic toilet facilities are the most critical determinants of child survival in urban areas of developing countries. the present situation stressed on the need for renewed emphasis on maternal and child healthcare and child nutrition programs. mapping path for progress to save our children would need be done strategically. we have the policies on hand, we have the means, to change the world so that every child will survive and has the opportunity to develop himself fully as a healthy human being. we need the political will--courage and determination to make that a reality. p - (c) sherbourne health centre: innovation in healthcare for the transgendered community james read introduction: sherbourne health centre (shc), a primary health care centre located in downtown toronto, was established to address health service gaps in the local community. its mission is to reduce barriers to health by working with the people of its diverse urban communities to promote wellness and provide innovative primary health services. in addition to the local communities there are three populations of focus: the lesbian, gay, bisexual, transgendered and transexual communities (lgbtt); people who are homeless or underhoused; and newcomers to canada. shc is dedicated to providing health services in an interdisciplinary manner and its health providers include nurses, a nurse practitioner, mental health counsellors, health promoters, client-resource workers, and physicians. in january shc began offering medical care. among the challenges faced was how to provide responsive, respectful services to the trans community. providers had considerable expertise in the area of counselling and community work, but little in the area of hormone therapy -a key health service for those who want to transition from one gender to another. method: in preparing to offer community-based health care to the trans community it was clear that shc was being welcomed but also being watched with a critical eye. trans people have traditionally experienced significant barriers in accessing medical care. to respond to this challenge a working group of members of the trans community and health providers was created to develop an overall approach to care and specific protocols for hormone therapy. the group met over a one year period and their work culminated in the development of medical protocols for the provision of hormone therapy to trans individuals. results: shc is currently providing health care to registered clients who identify as trans individuals (march ) through primary care and mental health programs. in an audit of shc medical charts (january to september ) female-to-male (ftm) and male-to-female (mtf) clients were identified. less than half of the ftm group and just over two-thirds of the mtf group presented specifically for the provision of hormones. based on this chart audit and ongoing experience shc continues to update and refine these protocols to ensure delivery of quality care. conclusion: this program is an example of innovative community-based health delivery to a population who have traditionally faced barriers. shc services also include counselling, health promotion, outreach and education. p - (c) healthy cities for canadian women: a national consultation sandra kerr, kimberly walker, and gail lush on march , the national network on environment and women's health held a pan-canadian consultation to identify opportunities for health research, policy change, and action. this consultation also worked to facilitate information sharing and networking between canadian women working as urban planners, policy makers, researchers, and service workers on issues pertaining to the health of women living in canadian cities. methods: for this research project, participants included front-line service workers, policy workers, researchers, and advocates from coast to coast, including francophone women, women with disabilities, racialized women, and other marginalized groups. the following key areas were selected as topics for du.bnes i alto kading .:auk of end·sugr ieaal clileue ia singapore, accounting for more than so% of new can singapore (nkfs) to embark on a prevention program (pp) empo~r d ahc j u f dieir condition bttter, emphasizing education and disease sdf·managemen lkilla a. essennal camponenn of good glycaemic control. we sought explore the effects of a pecialijed edu.:a on pro· pun od glycacmic conuol, as indicated by, serum hba ic values budine serum hba ic values were determined before un<k-rgmng the education progr ;am, which couisted of comprehensive dietary advice, ideal weight goals, and improving lipid profiln. serum hbaic values were obtained ar , , months later to determine impact of the program. analy • wu done uling paired !·tests significant reduction in hba le levels from ro month• was observed in females, chinese race, older age group(> so yean). ohew-ibmi ~ .nwm , wai hip ratio> l),up to primary and above secondary level education and those having om urine iclt showed that increasing hbalc levels ( ) had increasing urmary protein ( .± ; . ±i ih so± ) and crearinine (s .s ± s ± ; ioi± s) levels fbg rnults showed that the management nf d abetn m the nkfs preven· tion programme is effec;rive. results also indicated har hba le leve have a linnr trend wnh unnary protein and creatinine which are imponant determinants of renal diseate tal family-focused cinical palbway promoce politivc outcollln for ua inner city canu allicy ipmai jerrnjm care llctivirits in preparation for an infanr'' dilchargr honlr, and art m endnl lo improve effi.:k'fl.:tn of c.are. lere i paucity of tttran:h, and inconsi trncy of rnulta on ht-•m!*- of f m ly·fc"-'uw d nm a: to determinr whrthrr implrmentation of family.focuted c:pt n ntnn.tt.tl unit w"n mg an inner city ;ommunity drcl't'aki leftarh of lf•y (i.osi and rromclll'i family uo•fkllon and rt. j nest for dikhargr. md odt: family-focuk"d cpi data wm coll«ted for all infant• horn btrwttn and wft"k• t"lal mi atr who wrtt . dm ed to the ntonatal unit lmgdl of -.y . n. . day'o p c o.osi ind pma . d•mr., ho.nr . t . n. . ± i. i wb, p < o.os) wett n« fiamly f.lfrt n the pre.(]' poup. ~ .fxtmon icofn for famihn wrre high. and families noctd thc:y wnr mott prepued to ah thrar t..lby "'-· thett was .a cosi uving of s , (cdn) per patient d teharpd home n the pmi-cp poap c.-pated the p"''lfoup· cortclaion· lmplrmrnr.rion of family·foanrd c:p. in a nrona . i umt tc"fyidi an nnn an com· muniry decre.ned length of'"'" mft with a high dcgrft of family uujamon, and wrre coll~nt at least % percent of the kathmandu population lives in slum like conditions with poor access to basic health services. in these disadvantaged areas, a large proportion of children do not receive treatment due to inaccessibility to medical services. in these areas, diarrhea, pneumonia, and measles, are the key determinants of infant mortality. protein energy malnutrition and vitamin a deficiency persists and communicable diseases are compounded by the emergence of diseases like hiv/aids. while the health challenges for disadvantaged populations in kathmandu are substantial, the city has also experienced various forms of innovative and effective community development health programs. for example, there are community primary health centers established by the kathmandu municipality to deliver essential health services to targeted communities. these centers not only provide equal access to health services to the people through an effective management system but also educate them hy organizing health related awareness programs. this program is considered one of the most effective urban health programs. the paper/presentation this paper will review large, innovative, and effective urhan health programs that are operating in kathmandu. most of these programs are currently run by international and national ngos a) early detection of emerging diseases in urban settings through syndromic surveillance: data pilot study kate bassil of community resources, and without adequate follow-up. in november shelter pr.oviders ~et with hospital social workers and ccac to strike a working group to address some of th~ issues by mcre.asing knowledge among hospital staff of issues surrounding homelessness, and to build a stro?g workmg relationship between both systems in hamilton. to date the hswg has conducted four w~lkmg to~ of downtown shelters for hospital staff and local politicians. recently the hswg launched its ·~ool.k t for staff working with patients who are homeless', which contains community resources and gu dehnes to help with effective discharge plans. a scpi proposal has been submitted to incre~se the capacity of the hswg to address education gaps and opportunities with both shelters and hospitals around homelessness and healthcare. the purpose of this poster presentation is to share hamilton's experience and learnings with communities who are experiencing similar issues. it will provide for intera~tion around shared experiences and a chance to network with practitioners across canada re: best practices. introduction and objectives: canadians view health as the biggest priority for the federal government, where health policies are often based on models that rely on abstract definitions of health that provide little assistance in the policy and analytical arena. the main objectives of this paper are to provide a functional definition of health, to create a didactic model for devising policies and determining forms of intervention, to aid health professionals and analysts to strategize and prioritize policy objectives via cost benefit analysis, and to prompt readers to view health in terms of capacity measures as opposed to status measures. this paper provides a different perspective on health, which can be applied to various applications of health such as strategies of aid and poverty reduction, and measuring the health of an individual/ community/country. this paper aims to discuss theoretical, conceptual, methodological, and applied implications associated with different health policies and strategies, which can be extended to urban communities. essentially, our paper touches on the following two main themes of this conference: •health status of disadvantaged populations; and •interventions to improve the health of urban communities.methodology: we initially surveyed other models on this topic, and extrapolated key aspects into our conceptual framework. we then devised a theoretical framework that parallels simple theories of physkal energy, where health is viewed in terms of personal/societal health capacities and effort components.after establishing a theoretical model, we constructed a graphical representation of our model using selfrated health status and life expectancy measures. ultimately, we formulated a new definition of health, and a rudimentary method of conducting cost benefit analysis on policy initiatives. we end the paper with an application example discussing the issues surrounding the introduction of a seniors program.results: this paper provides both a conceptual and theoretical model that outlines how one can go about conducting a cost-benefit analysis when implementing a program. it also devises a new definition and model for health barred on our concept of individual and societal capacities. by devising a definition for health that links with a conceptual and theoretical framework, strategies can be more logically constructed where the repercussions on the general population are minimized. equally important, our model also sets itself up nicely for future microsimulation modeling and analysis.implications: this research enhances one's ability to conduct community-based cost-benefit analysis, and acts as a pedagogical tool when identifying which strategies provide the best outcome. p - (a) good playgrounds are hard to find: parents' perceptions of neighbourhood parks patricia tucker, martin holmes, jennifer irwin, and jason gilliland introduction: neighbourhood opportunities, including public parks and physical activity or sports fields hav~ been. iden.tified as correlates to physical activity among youth. increasingly, physical activity among children s bemg acknowledged as a vital component of children's lives as it is a modifiable determinant of childh~d obesity. children's use of parks is mainly under the influence of parents; therefore, the purpose of this study was to assess parents' perspectives of city parks, using london ontario as a case study.m~~: this qualitative study targeted a heterogeneous sample of parents of children using local parks w thm london. parents with children using the parks were asked for minutes of their time and if willing, a s.hort interview was conducted. the interview guide asked parents for their opinion 'of city parks, particularly the one they were currently using. a sample size of parents is expected by the end of the summer.results: preliminary findings are identifying parents concern with the current jack of shade in local parks. most parents have identified this as a limitation of existing parks, and when asked what would make the parks better, parents agree that shade is vital. additionally, some parents are recognizing the v poster sessions focused discussions during the consultation: . women in _poverty . women with disability . immi· grant and racialized women . the built and _physica_l environment. . . . . r its· participants voiced the need for integration of the following issues withm the research and policy :::na; t) the intersectional nature of urban women's health i~sues wh~ch reflects the reality of women's complex lives ) the multisectional aspect of urban wo_m~n s health, ss~es, which reflects the diversity within women's lives ) the interse~roral _dynamics within _womens hves and urban health issues. these concepts span multiple sectors -mdudmg health, educat n, and economics -when leveraging community, research, and policy support, and engaging all levels of government.policy jmplicatiom: jn order to work towards health equity for women, plans for gender equity must be incorporated nationally and internationally within urban development initiatives: • reintroduce "women" and "gender" as distinct sectors for research, analysis, advocacy, and action. •integrate the multisectional, intersectional, and intersecroral aspects of women's lives within the framework of research and policy development, as well as in the development of action strategies. • develop a strategic framework to house the consultation priorities for future health research and policy development (for example, advocacy, relationship building, evidence-based policy-relevant research, priority initiatives}.note: research conducted by nnewh has been made possible through a financial contribution from health canada. the views expressed herein do not necessarily represent the views of health canada.p - (c) drugs, culture and disadvantaged populations leticia folgar and cecilia rado lntroducci n: a partir de un proyecto de reducci n de daiios en una comunidad urbana en situ· aci n de extrema vulnerahilidad surge la reflexion sobre el lugar prioritario de los elementos sociocuhurales en el acceso a los servicios de salud de diferentes colectivos urbanos. las "formas de hacer, pensar y sentir" orientan las acciones y delimitan las posibilidades que tienen los individuos de definir que algo es o no problema, asf como tambien los mecanismos de pedido de ayuda. el analisis permanenre del campo de "las culturas cotidianas" de los llamados "usuarios de drogas" aporta a la comprension de la complejidad del tema en sus escenarios reales, y colabora en los diseiios contextualizados de politicas y propuestas socio-sanitarias de intervenci n, tornandolas mas efectivas.mitodos: esta experiencia de investigaci n-acci n que utiliza el merodo emografico identifica elementos socio estructurales, patrones de consumo y profundiza en los elementos socio-simb icos que estructuran los discursos de los usuarios, caracterizandolos y diferenciandolos en tanto constitutivos de identidades socia les que condicionan la implementaci n del programas de reduccion de daiios.resultados: los resultados que presentaremos dan cuenta de las caracteristicas diferenciadas v relaciones particulares ~ntre los consumidores de drogas en este contexto espedfico. a partir de este e~tudio de caso se mtentara co ? enzar a responder preguntas que entendemos significativas a la hora de pensar intcrvcnciones a la med da de poblaciones que comparten ciertas caracteristicas socio-culturales. (cuales serian las .motivaciones para el cambio en estas comunidades?, cque elementos comunitarios nos ayudan a i:nnstnur dema~~a? • cque tenemos para aprender de las "soluciones" que ellos mismos encuenrran a los usos problemat cos? methods: our study was conducted by a team of two researchers at three different sites. the mapping consisted of filling in a chart of observable neighbourhood features such as graffiti, litter, and boarded housing, and the presence or absence of each feature was noted for each city block. qualitative observations were also recorded throughout the process. researchers analyzed the compiled quantitative and qualitative neighbourhood data and then analyzed the process of data collection itself.results: this study reveals the need for further research into the effects of physical environments on individual health and sense of well-being, and perception of investment in neighbourhoods. the process reveals that perceptions of health and safety are not easily quantified. we make specific recommendations about the mapping methodology including the importance of considering how factors such as researcher social location may impact the experience of neighbourhoods and how similar neighbourhood characteristics are experienced differently in various spaces. further, we discuss some of the practical considerations around the mapping exercise such as recording of findings, time of day, temperature, and researcher safety.conclusion: this study revealed the importance of exploring conceptions of health and well-being beyond basic physical wellness. it suggests the importance of considering one's environment and one's own perception of health, safety, and well-being in determining health. this conclusion suggests that attention needs to be paid to the connection between the workplace and the external environment it is situated in. the individual's workday experience does not start and stop at the front door of their workplace, but rather extends into the neighbourhood and environment around them. our procedural observations and recommendations will allow other researchers interested in the effect of urban environments on health to consider using this innovative methodology. introduction: responding ro protests against poor medical attention for sexually assaulted women and deplorable conviction rates for sex offenders, in the late s, the ontario government established what would become over hospital-based sexual assault care and treatment centres (sactcs) across the province. these centres, staffed around the clock with specially trained heath care providers, have become the centralized locations for the simultaneous health care treatment of and forensic evidence collection from sexually assaulted women for the purpose of facilitating positive social and legal outcomes. since the introduction of these centres, very little evaluative research has been conducted to determine the impact of this intervention. the purpose of our study was to investigate it from the perspectives of sexually assaulted women who have undergone forensic medical examinations at these centres.method: women were referred to our study by sactc coordinators across ontario. we developed an interview schedule composed of both closed and open-ended questions. twenty-two women were interviewed, face-to-face. these interviews were approximately one-to-two hours in length, and were transcribed verbatim. to date, have been analyzed for key themes.results: preliminary findings indicate that most women interviewed were canadian born ( 'yo), and ranged in age from to years. a substantial proportion self-identified as a visible minority ( 'x.). approximately half were single or never married ( %) and living with a spouse or family of origin ( %). most were either students or not employed ( %). two-thirds ( %) had completed high school and onethird ( %) was from a lower socio-economic stratum. almost two-fifths ( %) of women perceived the medical forensic examination as revictimizing citing, for example, the internal examination and having blood drawn. the other two-thirds ( %) indicated that it was an empowering experience, as it gave them a sense of control at a time when they described feeling otherwise powerless. most ( %) women stated that they had presented to a centre due to health care concerns and were very satisfied ( % ) with their experiences and interactions with staff. almost all ( %) women felt supported and understood.conclusions: this research has important implications for clinical practice and for appropriately addressing the needs of sexually assaulted women. what is apparent is that continued high-quality medical attention administered in the milieu of specialized hospital-based services is essential. at the same time, we would suggest that some forensic evidence collection procedures warrant reevaluation. the study will take an experiential, approach by chroruclmg the impa~ of the transition f m the streets to stabilization in a managed alcohol program through the techruque of narrative i~:uiry. in keeping with the shift in thinking in the mental health fie!~ ~his stu~y is based on a paradigm of recovery rather than one of pathology. the "inner views of part c pants hves as they portray their worlds, experiences and observations" will be presented (charm~z, , ~· ~)-"i?e p~ of the study is to: identify barriers to recovery. it will explore the exj?cnence of ~n~t zanon pnor to entry into the program; and following entry will: explore the meanmg ~nd defirutto~s of r~overy ~~d the impact of the new environment and highlight what supports were instrumental m movmg pan apants along the recovery paradigm.p -st (a) treating the "untreatable": the politics of public health in vancouver's inner city introdudion: this paper explores the everyday practices of therapeutic programs in the treadnent of hiv in vancouver's inner city. as anthropologists have shown elsewhere, therapeutic programs do not siinply treat physical ailments but they shape, regulate and manage social lives. in vancouver's inner city, there are few therapeutic options available for the treatment of -ilv. public health initiatives in the inner city have instead largely focused on prevention and harm reduction strategies such as needle exchange programs, safe injection sites, and safer-sex education. epidemiological reports suggest that less than a quarter of those living with hiv in the downtown eastside (dtes) are taking antiretroviral therapies raising critical questions regarding the therapeutic economy of antiretrovirals and rights to health care for the urban poor.methods: this paper is drawn from ethnographic fieldwork in vancouver's otes neighborhood focusing on therapeutic programs for hiv treatment among "hard-to-reach" populations. the research includes participant-observation at inner city health clinics specializing in the treatment of hiv; semi· structured interviews with hiv positive participants, health care professionals providing hiv treatment, and administraton working in the field of inner city public health; and, lastly, observation at public meetings and conferences surrounding hiv treatment.r.awlts: hiv prevention and treatment is a central concern in the lives of many residents living in the inner city -although it is just one of many health priorities afflicting the community. concerns about drug resistance, cost of antiretrovirals, and illicit drug use means that hiv therapy for most is characterized by the daily observation of their medicine ingestion at health clinics or pharmacies. daily observed treatment (dot) is increasingly being adopted as a strategy in the therapeutic management of "untreatable" populations. dot programs demand a particular type of subject -one who is "compliant" to the rules and regimes of public health. over emphasis on "risky practices," "chaotic lives," and "~dh~rence" preve~ts the public health system from meaningful engagement with the health of the marginalized who continue to suffer from multiple and serious health conditions and who continue to experience considerable disparities in health.~ the ~ffec~s of hiv in the inner city are compounded by poverty, laclc of safe and affordable houamg, vanous llegal underground economies increased rates of violence and outbreaks of ~~~·~ly tr~nsmitted infections, hepatitis, and tuberculosi: but this research suggests 'that public health uunauves aimed at reducing health disparities may be failing the most vulnerable and marginal of citiztl s. margaret malone ~ vi~lence that occurs in families and in intimate relationships is a significant urban, ~unity, and pu~hc health problem. it has major consequences and far-reaching effects for women, ~~--renho, you~ sen on, and families. violence also has significant effects for those who provide and ukllc w receive health care violence · · i · · . all lasses, · is a soc a act mvolvmg a senous abuse of power. it crosses : ' : ' ~ s;nden, ag~ ~ti~, cultures, sexualities, abilities, and religions. societal responseshali ra y oc:used on identificatton, crisis intervention and services for families and individuajs.promoten are only "-"--:-g to add h · ' · i in intimate relationshi with"-~"'.". ress t e issues of violence against women and vjoence lenga to consider i~ m families. in thi_s p~per, i analyze issues, propose strategies, and note c~· cannot be full -...l'-~ whork towards erad canng violence, while arguing that social justice and equity y -. ucvcu w en thett are people wh mnhod: critical social theory, an analysis that addresses culturally and ethnically diverse communities, together with a population health promotion perspective frame this analysis. social determinants of health are used to highlight the extent of the problem of violence and the social and health care costs.the ottawa charter is integrated to focus on strategies for developing personal skills, strengthening community action, creating supportive environments, devdoping healthy public policies, and re-orientating health and social services. attention is directed to approaches for working with individuals, families, groups, communities, populations, and society.ratdts: this analysis demonstrates that a comprehensive interdisciplinary, multisectoral, and multifaceted approach within an overall health promoting perspective helps to focus on the relevant issues, aitical analysis, and strategies required for action. it also illuminates a number of interacting, intersecting, and interconnecting factors related to violence. attention, which is often focused on individuals who are blamed for the problem of violence, is redirected to the expertise of non-health professionals and to community-based solutions. the challenge for health promoters working in the area of violence in families and in intimate relationships is to work to empower ourselves and the communities with whom we work to create health-promoting urban environments. social justice, equiry, and emancipatory possibilities are positioned in relation to recommendations for future community-based participatory research, pedagogical practices for health care practitioners, and policy development in relation to violence and urban health. the mid-main community health center, located in vancouver british columbia (bc), has a diverse patient base reflecting various cultures, languages, abilities, and socio-economic statuses. due to these differences, some mid-main patients experience greater digital divide barriers in accessing computers and reputable, government produced consumer health information (chi) websites, such as the bc healthguide and canadian health network. inequitable access is problematic because patient empowerment is the basis of many government produced chi websites. an internet terminal was introduced at mid-main in the summer of , as part of an action research project to attempt to bridge the digital divide and make government produced chi resources useful to a broad array of patients. multi-level interventions in co-operation with patients, with the clinic and eventually government ministries were envisioned to meet this goal. the idea of implementing multi-level interventions was adopted to counter the tendency in interactive design to implement a universal solution for the 'ideal' end-user [ ), which discounts diversity. to design and execute the interventions, various action-oriented and ethnographic methods were employed before and during the implementation of the internet terminal. upon the introduction of the internet terminal, participant observation and interviews were conducted using a motion capture software program to record a digital video and audio track of patients' internet sessions. this research provided insight into the spectrum of patients' capacities to use technology to fulfil their health information needs and become empowered. at the mid-main clinic it is noteworthy that the most significant intervention to enhance the usefulness of chi websites for patients appeared to be a human rather than a technological presence. as demonstrated in other ethnographic research of community internet access, technical support and capacity building is a significant component of empowerment ( ). the mid-main wired waiting room project indicates that medical practitioners, medical administrators, and human intermediaries remain integral to making chi websites useful to patients and their potential empowerment. ( ) over the past years the environmental yo~th alliance has been of~ering a.youth as~t. mappin~ program which trains young people in community research and evaluation. wh ~st the positive expenenc~ and relationships that have developed over this time attest to the success of this program, no evaluations has yet been undertaken to find out what works for t.he youth, what ~ould be changed, and what long term outcomes this approach offers for the youth, their local community, and urban governance. these topics will be shared and discussed to help other community disorganizing and uncials governments build better, youth-driven structures in the places they live.p - (a) the world trade center health registry: a unique resource for urban health researchers deborah walker, lorna thorpe, mark farfel, erin gregg, and robert brackbill introduction: the world trade center health registry (wfchr) was developed as a public health response to document and evaluate the long-term physical and mental health effects of the / disaster on a large, diverse population. over , people completed a wfchr enrollment baseline survey, creating the largest u.s. health registry. while studies have begun to characterize / bealth impacts, questions on long-term impacts remain that require additional studies involving carefully selected populations, long-term follow-up and appropriate physical exams and laboratory tests. wtchr provides an exposed population directory valuable for such studies with features that make ita unique resource: (a) a large diverse population of residents, school children/staff, people in lower man· hattan on / including occupants of damaged/destroyed buildings, and rescue/recovery/cleanup work· ers; (b) consent by % of enrollees to receive information about / -related health studies; (c) represenration of many groups not well-studied by other researchers; (c) email addresses of % of enrollees; (d) % of enrollees recruited from lists with denominator estimates; and (e) available com· parison data for nyc residents. wfchr strives to maintain up-to-date contact information for all enrollees, an interested pool of potential study participants. follow-up surveys are planned.methods: to promote the wtchr as a public health resource, guidelines for external researcher.; were developed and posted on (www.wtcregistry.org) which include a short application form, a twopage proposal and documentation of irb approval. proposals are limited to medical, public health, or other scientific research. researchers can request de-identified baseline data or have dohmh send information about their studies to selected wfchr enrollees via mail or email. applications are scored by the wtchr review committee, comprised of representatives from dohmh, the agency for toxic subst~nces and disease registry, and wtchr's scientific, community and labor advisory committees. a data file users manual will be available in early fall .~suits: three external applications have been approved in , including one &om a non-u.s. ~esearcher, all requesting information to be sent to selected wtchr enrollees. the one completed mail· mg~~ wtchr enrollee~ (o , wfc tower evacuees) generated a positive survey response rate. three additional researchers mtend to submit applications in . wfchr encourages collaborations between researchers and labor and community leaders.conclusion: studies involving wtchr enrollees will provide vital information about the long· term health consequences of / . wtchr-related research can inform communities, researcher.;, policy makers, health care providers and public health officials examining and reacting to and other disasters. t .,. dp'"f'osed: thi is presentation will discuss the findings of attitudes toward the repeat male client iden· ie as su e a and substance us'n p · · · · i · 'd . . - g. articipants will learn about some identified effective strategies or service prov ers to assist this group of i · f men are oft · d bl men. n emergency care settings, studies show that this group en viewe as pro emaric patient d i r for mental health p bl h h an are more ikely to be discharged without an assessmen !) ea rofr ems t. an or er, more cooperative patients (forster and wu · hickey er al., · r y resu ts om this study suggest th · · ' ' l · d tel' mining how best to h . d at negative amtudes towards patients, difficu nes e · as well pathways l_e_ p patientsblan ~ck of conrinuity of care influence pathways to mental health care. • uc\:ome pro emat c when p ti k · che system. m a ems present repeatedly and become "get stuc id methods: semi-structured intervie d . · (n= ), ed nurses (n= ) other ed ;s were con ucted with male ed patients (n= ), ed phys oans ' sta (n= ) and family physicians (n= ). patients also completed a poster sessions v diagnostic interview. interviews were tape-recorded, transcribed verbatim and managed using n . transcripts were coded using an iterative process and memos prepared capture emergent themes. ethics approval was obtained and all participants signed a detailed informed consent form.introduction: urban settings are particularly susceptible to the emergence and rapid spread of nt•w or rare diseases. the emergence of infectious diseases such as sars and increasing concerns over the next influenza pandemic has heightened interest in developing and using a surveillance systt·m which detects emerging public health problems early. syndromic surveillance systems, which use data b, scd on symptoms rather than disease, offer substantial potential for this by providing near-real-rime data which are linked to an automated warning system. in toronto, we are piloting syndromic data from the · emergency medical services (ems) database to examine how this information can be used on an ongoing basis for the early detection of syndromes including heat-related illness (hri), and influenza-like-illness (ill). this presentation will provide an outline of the planned desi_gn of this system and proposed evaluation. for one year, call codes which reflect heat-related illness or influenza-like-illness will be selected and searched for daily using software with a multifactorial algorithm. calls will he stratified by call code, extracted from the -ems database and transferred electronically to toronto public health. the data will be analyzed for clusters and aberrations from the expected with the realtime outbreak and disease surveillance (rods) system, a computer-based public health tool for the early detection of disease outbreaks. this -ems surveillance system will be assessed in terms of its specificity and sensitivity through comparisons with the well-established tracking systems already in place for hr! and ill. others sources of data including paramedic ambulance call reports of signs and . this study will introduce complementary data sources t~ the ed ch e~ complamt an~ o~~rthe-counter pharmacy sales syndromic surveillance data currently bemg evaluated m ~ther ontar~o cltles. . syndromic surveillance is a unique approach to proactive(~ dete~tmg early c.hangesm the health status of urban communities. the proposed study aims to provide evidence of differential effectiveness through investigating the use of -ems call data as a source of syndromic surveillance information for hr! and ili in toronto. introduction: there is strong evidence that primary care interventions, including screening, brief advi<:e, treatment referral and pharmacotherapy are effective in reducing morbidity and mortality caused by substance abuse. yet physicians are poor at intervening with substance users, in part because of lack of time, training and support. this study examines the hypothesis that shared care in addictions will result in decreased substance use and improved health status of patients, as well as increased use of primary care interventions by primary care practitioners (pcps). methods: the addiction medicine service (ams) at st. joseph's health centre's family medicine department is in the process of being transformed from its current structure as a traditional consult service into a shared care model called addiction shared care (asc). the program will have three components: education, office systems and clinical shared care. as opposed to a traditional consult service, the patient will be booked with both a primary care liaison worker (pcl) and addictions physician. patients referred from community physicians, the emergency department and inpatient medical and psychiatric wards will be recruited for the study as well as pcps from the surrounding community. the target sample size is - physicians and a similar number of patients. after initial consult, patient will be recruited into the study with their consent. the shared-case model underlines the interaction and collaboration with the patient's main pcp. asc will provide them with telephone consults, advice, support and re-assessment for their patients, as well as educational sessions and materials such as newsletters and informational kits.results: the impact of this transition on our patient care and on pcp's satisfaction with the asc model is currently being evaluated through a grant provided by the ministry of health & long term care. a retrospective chart review will be conducted using information on the patient's substance use, er/clinic visits, and their health/mood status. pcp satisfaction with the program will be measured through surveys and focus groups. our cost-effectiveness analysis will calculate the overall cost of the program per patient..conclusion: this low-cost service holds promise to serve as an optimal model and strategy to improve outcomes and reduce health care utilization in addict patients. the inner city public health project introduction the inner city public health project (icphp) was desi.gned to explore new an~ innovative ways to reach marginalized inner city populations that par-t c pate m high health-nsk beha~ ors. much of this population struggles with poverty, addictions, mental illness and homelessness, creatmg barriers to accessing health services and receiving follow-up. this pro ect was de~igned to evaluat~ .~e success of offering clinics in the community for testing and followup of communicable diseases uuhzmg an aboriginal outreach worker to build relationships with individuals and agencies. v n(demographics~ history ~f testi~g ~nd immunization and participation in various health-risk behaviors), records of tesnng and mmumzat ons, and mterviews with partner agency and project staff after one year.. results: t~e chr ~as i~strumental in building relationships with individuals and partner agencies ' .° the c~mmun_ ~ re_sultmg m req~ests for on-site outreach clinics from many of the agencies. the increase m parnc pat n, the chr mvolvement in the community, and the positive feedback from the agen? staff de~onstrated that.the project was successfully creating partnerships and becoming increasingly integrated m the community. data collected from clients at the initial visit indicated that the project was reaching its target populations and highlighted the unique health needs of clients, the large unmet need for health services and the barriers that exist to accessing those services. ~usion: the outreach clinics were successful at providing services to target populations of high health-nsk groups and had great support from the community agencies. the role of the chr was critical to the success of the project and proved the value of this category of health care worker in an urban aboriginal population. the unmet health needs of this disadvantaged population support the need for more dedicated resources with an emphasis on reducing access barriers. building a caring community old strathcona's whyte avenue, a district in edmonton, brought concern about increases in the population of panhandlers, street people and homeless persons to the attention of all levels of government. the issue was not only the problems of homelessness and related issues, but feelings of insecurity and disempowerment by the neighbourhood residents and businesses. their concerns were acknowledged, and civic support was offered, but it was up to the community itself to solve the problem. within a year of those meetings, an adult outreach worker program was created. the outreach worker, meets people in their own environments, including river valley camps. she provides wrap-around services rooted in harm reduction and health promotion principles. her relationship-based practice establishes the trust for helping clients with appropriate housing, physical and/or mental health issues, who have little or no income and family support to transition from homelessness. the program is an excellent example of collaboration that has been established with the businesses, community residents, community associations, churches, municiple services, and inner-city agencies such as boyle street community services. statistics are tracked using the canadian outcomes research institute homes database, and feedback from participants, including people who are street involved. this includes an annual general meeting for community and people who are homeless. the program's holistic approach to serving the homeless population has been integral, both in creating community awareness and equipping residents and businesses to effectively interact with people who are homeless. through this community development work, the outreach worker engages old strathcona in meeting the financial and material needs of the marginalized community. the success of this program has been surprising -the fact is that homeless people's lives are being changed; one person at a time and the community has been changed in how they view and treat those without homes. over two years, the program has successfully connected with approximately seventy-five individuals who call old strathcona home, but are homeless. thirty-six individuals are now in homes, while numerous others have been assisted in obtaining a healthier and safer lifestyles by becoming connected with other social/health agencies. the program highlights the roots of homelessness, barriers to change and requirements for success. it has been a thriving program and a model that works by showing how a caring community has rallied together to achieve prosperous outcomes. the spn has created models of tb service delivery to be used m part~ers~ p with phannaceunca compa-. · · -. t' ns cooperatives and health maintenance orgamzanons (hmos). for example, the mes, c v c orgamza , . · b tb d' · spn has established a system with pharmaceutical companies that help patients to uy me cmes at a special discounted rate. this scheme also allows patients to get a free one-_month's worth of~ dru_g supply if they purchase the first months of their regimen. the sy_s~e~s were ~es gned to be cm~pattble with existing policies for recording and documentation of the ph hppme national tuberculosis program (ntp). aside from that, stakeholders were also encouraged to be dots-enabled through the use of m~nual~ and on-line training courses. the spn initiative offers an alternative in easing the burden of tb sc:rv ce delivery from rhe public sector through the harnessing of existing private-sector (dsos). the learnmgs from the spn experience would benefit groups from other locales that _work no~ only on ~ but other health concerns as well. the spn experience showcases how well-coordinated private sector involvements help promote social justice in health delivery in urban communities.p - (c) young people in control; doing it safe. the safe sex comedy juan walter and pepijn v. empelen introduction: high prevalence of chlamydia and gonorrhoea have been reported among migrants youth in amsterdam, originating from the dutch antilles, suriname and sub-sahara africa. in addition, these groups also have high rates of teenage-pregnancy (stuart, ) and abortions (rademakers ), indicating unsafe sexual behaviour of these young people. young people (aged - ) from the so· called urban scene (young trendsetters in r&b/hip hop music and lifestyle) in amsterdam have been approached by the municipal health service (mhs) to collaborate on a safe sex project. their input was to use comedy as vehicle to get the message a cross. for the mhs this collaboration was a valuable opportunity to reach a hard-to-reach group.mdhods: first we conducted a need assessment by means of a online survey to assess basic knowledge and to similtaneously examine issues of interest concerning sex, sexuality, safer sex and the opposite sex. second, a small literature study was conducted about elements and essential conditions for succesful entertainment & education (e&e) (bouman ), with as most important condition to ensure that the message is realistic (buckingham & bragg, ) . third a program plan was developed aiming at enhancing the stl/hiv and sexuality knowledge of the young people and addressing communication and educational skills, by means of drama. subsequently a safe sex comedy show was developed, with as main topics: being in love, sexuality, empowerment, stigma, sti, hivand safer sex. the messages where carried by a mix of video presentation, stand up comedy, spoken word, rap and dance.results: there have been two safe sex comedy shows. the attendance was good; the group was divers' with an age range between and year, with the majority being younger than year. more women than men attended the show. the story lines were considered realistic and most of the audients recognised the situations displayed. eighty percent of the audients found the show entertaining and % found it edm:arional. from this %, one third considers the information as new. almost all respondents pointed our that they would promote this show to their friends.con.clusion: the s.h<_>w reached the hard-to-reach group of young people out of the urban scene and was cons d_ered entert~mmg, educational and realistic. in addition, the program was able in addressing important issues, and impacted on the percieved personal risk of acquiring an sti when not using condoms, as well as on basic knowledge about stl's. introduction: modernity has contributed mightily to the marginality of adults who live with mental illnesses and the subsequent denial of opportunities to them. limited access to social, vocational, educational, and residential opportunities exacerbates their disenfranchisement, strengthening the stigma that has been associated with mental illness in western society, and resulting in the denial of their basic human rights and their exclusion from active participation in civil society. the clubhouse approach tn recovery has led to the reduction of both marginality and stigma in every locale in which it has been implemented judiciously. its elucidation via the prism of social justice principles will lead to a deeper appreciation of its efficacy and relevance to an array of settings. methods: a review of the literature on social justice and mental health was conducted to determine core principles and relationships between the concepts. in particular, fondacaro and weinberg's ( ) conceptualization of social justice in community psychology suggests the desirability of the clubhouse approach in community mental health practice. a review of clubhouse philosophy and practice has led to the inescapable conclusion that there is a strong connection between clubhouse philosophy-which represents a unique approach co recovery--and social justice principles. placing this highly effective model of community mental health practice within the context of these principles is long overdue. via textual analysis, we will glean the principles of social justice inherent in the rich trove of clubhouse literature, particularly the international standards of clubhouse development.results: fondacarao and weinberg highlight three primary social justice themes within their community psychology framework: prevention and health promotion; empowerment, and a critical pnsp<"<·tive. utilizing the prescriptive principles that inform every detail of clubhouse development and th<" movement toward recovery for individuals at a fully-realized clubhouse, this presentation asserts that both clubhouse philosophy and practice embody these social justice themes, promote human rights, and empower clubhouse members, individuals who live with mental illnesses, to achieve a level of wdl-heing and productivity previously unimagined.conclusion: a social justice framework is critical to and enhances an understanding of the clubhouse model. this model creates inclusive communities that lead to opportunities for full partic pil!ion civil society of a previously marginalized group. the implication is that clubhouses that an· based on the international standards for clubhouse programs offer an effective intervention strategy to guarantee the human rights of a sizable, worthy, and earnest group of citizens. to a drastic increase in school enrollment from . million in to . million in .s. however, while gross enrollment rates increased to °/., in the whole country after the introduction of fpe, it remained conspicuously low at % in the capital city, nairobi. nairobi city's enrollment rate is lower .than thatof all regions in the country except the nomadic north-eastern province. !h.e.d sadvantage of children bas_ed in the capital city was also noted in uganda after the introduction of fpe m the late s_-many_ education experts in kenya attribute the city's poor performance to the high propornon of children hvmg m slums, which are grossly underserved as far as social services are concerned. this paper ~xammes the impact of fpe and explores reasons for poor enrollment in informal settlements m na rob city. methods: the study utilizes quantitative and qualitative schooling data from the longitudinal health and demographic study being implemented by the african population and health research center in two informal settlements in nairobi. descriptive statistics are used to depict trends in enrollment rates for children aged - years in slum settlements for the period - . results: the results show that school enrollment has surprisingly steadily declined for children aged - while it increased marginally for those aged - . the number of new enrollments (among those aged years) did not change much between and while it declined consistently among those aged - since . these results show that the underlying reasons for poor school attendance in poverty-stricken populations go far beyond the lack of school fees. indeed, the results show that lack of finances (for uniform, transportation, and scholastic materials) has continued to be a key barrier to schooling for many children in slums. furthermore, slum children have not benefited from fpe because they mostly attend informal schools since they do not have access to government schools where the policy is being implemented.conclusion: the results show the need for equity considerations in the design and implementation of the fpe program in kenya. without paying particular attention to the schooling needs of the urban poor children, the millennium development goal aimed at achieving universal primary education will remain but a pipe dream for the rapidly increasing number of children living in poor urban neighborhoods.ps- (c) programing for hiv/aids in the urban workplace: issues and insights joseph kamoga hiv/aids has had a major effect on the workforce. according to !lo million persons who are engaged in some form of production are affectefd by hiv/aids. the working class mises out on programs that take place in communities, yet in a number of jobs, there are high risks to hiv infection. working persons sopend much of their active life time in workplaces and that is where they start getting involved in risky behaviour putting entire families at risk. and when they are infected with hiv, working people face high levels of seclusion, stigmatisation and some miss out on benefits especially in countries where there are no strong workplace programs. adressing hiv/aids in the workplace is key for sucessfull responses. this paper presents a case for workplace programing; the needs, issues and recommendations especially for urban places in developing countries where the private sector workers face major challenges. key: cord- - fw hrbl authors: silva, p. j. s.; pereira, t.; nonato, l. g. title: robot dance: a city-wise automatic control of covid- mitigation levels date: - - journal: nan doi: . / . . . sha: doc_id: cord_uid: fw hrbl we develop an automatic control system to help to design efficient mitigation measures for the covid- epidemic in cities. taking into account parameters associated to the population of each city and the mobility among them, the optimal control framework suggests the level and duration of protective measures that must be implemented to ensure that the number of infected individuals is within a range that avoids the collapse of the health care system. compared against other mitigation measures that are implemented simultaneously and in equal strength across cities our method has three major particularities when: accounts for city commute and health infrastructure: it takes into account the daily commute among cities to estimate the dynamics of infected people while keeping the number of infected people within a desired level at each city avoiding the collapse of its health care system. city-specific control: it allows for orchestrating the control measures among cities so as to prevent all cities to face the same level control. the model tends to induce alternation between periods of stricter controls and periods of a more normal life in each city and among the cities. flexible scenarios: it is flexible enough to allow for simulating the impact of particular actions. for example, one can simulate the how the control all cities change when the number of care beds increases in specific places. therefore, our method creates an automatic dance adjusting mitigation levels within cities and alternating among cities as suggested in~cite{pue }. this automatic dance may help the city economy and orchestration of resources. we provide case studies using the major cities of the state of sao paulo given by using estimates on the daily mobility among the cities their health care system capacity. we use official data in our case studies. however, sub-notification of infected people in brazil is notoriously high. hence the case study should not be considered as a real world policy suggestion. it high sub-notification is taken into account, the optimal control algorithm will suggest stricter mitigation measures, as also shown in the case studies. surprisingly, the total duration of the protocol for the state is barely affected by the sub-notification, but the severity of such protocols is strengthened. this stresses a twofold implication, first, the protocol depends on high-quality data and, second, such optimal and orchestrated protocol is robust and can be adjusted to the demand. after the first cases of covid- appeared in brazil on february , the state of são paulo was the first to adopt social distancing on march , after the first school closures on march . the social distancing protocol played a major role to control the rapidly increasing number of cases and thereby protecting the health care system [ ] . while an early implementation of an aggressive protocol of social distancing is effective, it has three major drawbacks: long implementation: a social distancing protocol, or any other mitigation strategy, must be implemented over many months. otherwise, it only causes a delay in the spreading of the virus while the peak of infected individuals remains virtually unchanged. this means that short social distancing only postpones the main issues. simultaneous implementation: since the whole state follows the same protocol, cities in the countryside must start it early, while the disease is still in the first stages and they still can cope with the number of cases, ignoring that the peak of cases does not happen at the same time for all cities. homogeneous protocol across cities: the protocol ignores the distinct roles cities play economically as well as their structure such as hospital and critical care beds. now, deep into a seven weeks long protocol, the control measures will be slowly relaxed starting on may st. this means that in the state of são paulo, and in fact in the whole country, another social distancing protocol must be implemented again in the near future. research shows that intermittent social distancing protocol will need to be implemented in the next two years [ ] most likely in an intermittent way, dancing between periods of mitigation and normal life [ ] . this is troublesome as the economies of developing countries cannot cope with such extended lockdowns [ ] . there is an urgent need to develop tools that may help policy-makers to device intelligent lockdown systems that predict where, how long, and to what extent the social distancing protocol must be implemented. probably such decisions must be taken at a city level, as each city will have its own economical, geographical, and infrastructural needs. our project addresses this challenge by developing a tool that suggests the level of mitigation needed for different cities at different moments, thereby aiming to alleviate the disruption to the activities while protecting the city's health system. however, we must emphasize that such approach depends on the data quality to estimate the current status of the pandemic. in this sense, it is also a proof of concept of what can be achieved with high quality widespread testing and good estimates of population movement to better understand the disease dynamics. the three major benefits of the algorithm are: . it takes into account the city health system capacity to predict the optimal measures. . it is flexible to incorporate control policies such as preventing full country lockdown. . it provides a city specific timing and extent of control implementation. . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted may , . . https://doi.org/ . / . . . doi: medrxiv preprint night day figure : daily dynamics of workers traveling to nearby cities. the boxes represent the city's total population. workers travel to adjacent cities and change the effective population of the city during the day. these workers can get infected at their workplace and serve as a source of infection during the night. for better visualization, we show only susceptible (green) and infected (red). individuals can be in one of the following states susceptible (s), exposed (e), infected (i), and recovered (r) [ ] . we take into account the fact that during the control protocol most travels between cities are due to the workforce: the workers leave their city to work in another one and return during the evening. thus, we divide the susceptible population of the city into the population that stays within it and the population that commutes to work. during the day: during working hours the available population of the ith city can be increased by the inflow of people workers (resp. outflow) giving an effective population which can be larger (resp. smaller) than the city's own population. we assume for now that susceptible individuals of the ith city going to the jth can only be infected there during the day. during the night: as workers come back to their city the model reduces to the standard seir model where cities do not interact and have their own population. full day cycle: because workers move in and out at well defined times we approximate the movement dynamics as a step function. so all workers move out and come back at the same time. let α be a square pulse modeling this cycle, so that α(t) = when t is the range of working hours (here from am to pm) and zero otherwise. a representation of the daily cycle is exhibited in figure . population splitting from data: the model needs a commuting matrix p i j (t) that contains daily accumulated percentage of inhabitants of i that travels to j. here, p i j may be updated daily. we are assuming that there is no correlation between the states and travels. see further details in app. a. in the seir models above, the parameter r t , the reproduction number at time t is usually a constant r that represents how many people a sick person infects if all other individuals are susceptible. the main objective of control measures is to decrease r t to a lower level, bringing the spread to a desired . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. (which was not certified by peer review) the copyright holder for this preprint this version posted may , . . level. therefore the problem of choosing such r t can be seen as an optimal control problem where the r t is the control variable that drives the disease trajectory to an acceptable, or even a desirable, state. this control problem can then be approximated by an optimization model after we devise a discretization scheme for the ode. since the seir model is not stiff, it is possible to use simple explicit integration methods and still get good approximations of the trajectory. we used the modified euler's algorithm, also known as heun's method [ ] , that computes explicit approximations of the trajectory s t , e t , i t , r t for each day given the initial values s , e , r , i and the reproduction values r t . since the integration method is simple, it can be described as a constraint set of a regular optimization problem. this problem can then be enriched with extra constraints and an objective function arriving at a conceptual model that must be solved by an optimization algorithm. since the seir model is nonlinear, the final optimization problem will also be nonlinear. finally, in order to take into account the coupling between the dynamics of the epidemic among all cities, described in . , a single problem has to solve the differential equations and choose the target reproduction level of all cities simultaneously. in our first implementation, we are adding a constraint to the variable i t for each city at each day. by doing this we try to control for the maximum level of infection that is allowed to avoid saturation of the health system. another group of constraints tries to avoid abrupt changes of the control r t , either fixing it in a time window or adding a total variation regularization [ ] . as objective we aim to balance between to main goals: trying to enforce the most relaxed control measures, by minimizing the mean deviation of r t and r , and alternating stricter controls in different cities. such objectives must be carefully balanced to take into account the economical importance of each city for example. at this first implementation we are using the square of the population as our main measure for the importance of each city. in a real world application such weights must be given by the decision-makers taking into account different economical and even political aspects. finally the optimization problem was coded using the modeling language jump [ ] . this is a julia [ ] package that allow us to easily describe the model and that efficiently interfaces with different solvers. it also takes care of efficiently computing the first and second derivatives needed by the solvers. such flexibility is essential, as the model will evolve with time and should be easy to adapt. to actually solve the optimization problem we are using ipopt [ ] , a high performance large scale nonlinear optimization solver, with the ma linear equation solver [ ] that is able to exploit multiple cores. for more details and specific formulas for the constraints and objective see appendix b. we discuss case studies involving possible scenarios of covid- control in the major cities of the state of são paulo. our control depends on the data quality, ranging from the city health infrastructure to the evolution of the number of cases. the latter is notoriously compromised in brazil [ ] . thus, for sake of comparison, we will show three scenarios: the current social distancing protocol, optimal control taking into account the office data, and finally, optimal control taking into account sub notification. in all cases we use mobility matrices estimated from anonymized mobile phone data [ ] . current social distancing only. this scenario uses official government data, which is sub-notified [ ] . assuming that social distancing policy started in march is kept until the end of june with the current effectiveness, we find that the peak of infected people in são paulo is reached in early july, while for the other cities in the metropolitan region of são paulo will face the peak of the epidemic . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . figure : prediction of covid- spread under the current social distancing level. we take into account commuting among cities and consider the official data. the prediction assumes that the social distancing protocol implemented in the state of são paulo would continue until july and with the same effectiveness. the infected population in the city of são paulo would be above . % for over two months causing a full collapse of the health system. outbreak in august, as shown in figure . são paulo city would have more than % of its population infected for about two full months, from early june to early august. an optimistic estimate (including campaign hospitals) shows that the são paulo health system has a maximum capacity of . % of the population infected. optimal and flexible control. as we discussed in the introduction our approach has three major advantages that we illustrate bellow by adjusting them to following measures . we fixed the maximal percentage of infected to be . % for the city of são paulo and . % for the countryside. this corresponds to an optimistic estimate of the health care capacity. . we implement a control protocol where cities aim for distinct control measures to prevent a full state lockdown and thus keep the local state economy running. . for the official data, our protocol is allowed to seek for controls with a minimal reproduction number . when taking into account sub-notification we implement an initial control phase where the minimal reproduction number is . . this is necessary because some cities already start above the threshold level for the infected, described above, while others we reach it in a few days due to the initial dynamics. as a consequence, each city follow the protocol according to their own need and will have their starting and stopping time of control which takes into account city to city commutes. office government data: in the left inset of figure , we show the results of the above implementation using official data released by the brazilian government. we provide control measures in six levels according to how strict they need to be ranging from no control (white) to severe (red). each city will have its control target to protect its health system. the optimal control provides distinct protocols according to the city role in the state. for instance, guarulhos has severe control which is gradually . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . figure : impact of the optimal control protocol implemented in the state of são paulo. the control protocol does not allow for the infected population in the city of são paulo to surpass . % and in the countryside . % (this would roughly correspond to take campaign hospitals into consideration). in the left inset, we show the situation with social distancing only (blue) and with optimal control (beige) where the infected population never exceeds . % as set in the control. in the right inset, our approach provides levels of control for the city of são paulo. this prediction performed using the official government data. decreased until the city is back to open, whereas a nearby city santo andré swings between a period of severe control to open. the optimal control solutions have three remarkable aspects: -the control releases são paulo earlier than other cities. as são paulo health system can serve twice the number of infected people than other cities, the control to end much earlier there. -countryside cities such as araçatuba, ribeirão preto e rio preto, could start the control two weeks later than the cities in the greater são paulo. they follow the control until late september when they alternate between two weeks of lock-down and no control. -most cities in the metropolitan area of são paulo can start the intermittent fortnightly distancing periods much earlier, by mid-august. during the period of intermittent control, the cities, mainly in the countryside, do not stop at the same time, an import aspect to keep the economy always running in part of the state during the epidemic outbreak. taking into account sub-notification: in the right inset of figure , we run the optimal control taking into account the strong sub-notification in the official data [ ] . clearly, there is no margin to manoeuvre and the severe control starts straight away. however, increasing the number of infected twelve-fold only changes slightly the duration of the optimal control protocol. notice that by taking into account sub-notification severe control is applied more often. in particular, severe control must be imposed during june, after that the level of control is progressively relaxed, starting the opening period from mid-august. notice that if a proper level of control is imposed in specific time intervals the duration of control increases in only about two weeks, but at a much more moderate level in such extra weeks. . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . figure : prediction of optimal control for major cities in the state of são paulo. the protocol changes every two weeks and optimizes the level control and the timing to apply the control measures. thus each city can meet its own needs to curb the spreading. in the left inset, we show the optimal control taking into account the official data. in the right inset, we take into account a sub-notification. we start the discussion emphasizing the importance of reliable data to convert the scenarios simulated by our approach in concrete actions. using official data, the left inset of figure shows that after one month of social distancing in são paulo state, the control could be avoided in may for most cities in the countryside of são paulo state if the only objective is to preclude the collapse of the health care system. if the simulation takes into account sub-notification, such relief is not feasible. in fact, cities in the countryside of the state as well as in the metropolitan area of são paulo must undergo a severe mitigation during the first two weeks of may. cities in the countryside of the state can only relax the control in the second fortnight of may. therefore, without reliable data it is complicated to simulate scenarios with low degree of uncertainty, making evident the need for testing the population in a broad scale in order to take secure actions. figure presents another scenario simulated by our methodology. in this example we take into account that the epidemic outbreak ends first in são paulo than in other cities. therefore, from september on, the simulation makes % of the hospital beds from são paulo available to the other cities. the larger number of beds available for other cities allows an increase in the number of infected people in the other cities, shortening the period of rigid control, mainly for cities in interior of the state, in about days, from early october to mid august. notice how the black curves goes above halfway after september, showing a larger number of people is infected in each city, but still under the admissible limit. the intermittent period of severe control are also shortened in about one month. the case studies discussed above shows the power of the proposed methodology in simulating different scenarios and henceforth enabling decision-making agents to analyze multiple alternatives so as to balance city-wise health system capacity and economic factors over são paulo state. level of control and actions adapted to a city level. the outcome of the optimization is the reproduction number the city must attain during the implementation phase of the protocol. . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . figure : using the health care infrastructure of the city of são paulo to assist others. the protocol changes every two weeks and optimizes the level control and the timing to apply the control measures. in late august, when são paulo has already passed the peak of epidemic outbreak, half of its hospital beds are made available to assist other cities, in the interior and in metropolitan area, shortening the time interval of severe control policy in those cities. left: official data; right: assuming sub-notified data. it is mandatory that we translate these variables into actions that policy-makers can implement at a city level. the reproduction number is sensitive to the density of the population and services level. we developed a city based flexible control protocol for covid- mitigation and used cities in the state of são paulo as a case study. the protocol takes into account infrastructure, care beds and mobility data from the cities to plan an optimal control strategy. here, we focused on strategies that avoid total state lockdown and thus keep the economy running and open opportunity to use medical resources in an efficient way. the recommended mitigation taking into account the official government data is is clearly different to the recommendations when we take sub-notification into account. surprisingly, the total duration of the control remains almost unaffected. as we showed, the quality of the recommendations depends strongly on the data. our control can be updated dynamically and can integrate new data on the fly. we consider a set of k cities with fixed population where n i is the total population. we divide the susceptible population of city i into classes aŝ s i j = population that leave city i to work in city j and similarly for the other states e,i, and r. during the day: the effective population is assumed constant throughout the day but can present daily variations. here u in n is neighbor inflow susceptibles of the ith city going to the jth can only be infected there. thus, where κ is the fraction of infected that can still commute and hence spread the disease elsewhere. for now, we consider κ = and thenṠ as we consider the absolute population the reproduction number is scaled according to the available population, which is assumed constant during the day. next we do two steps: (i) normalize the population s i + e i + i i + r i = , and thus, (ii) write in an equation for s i = k j= s i j yieldinġ . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . https://doi.org/ . / . . . doi: medrxiv preprint where p eff population splitting from data: the fraction of the population s i j can be estimated using a matrix that describes the mobility between the cities made available in [ ] . it has at each entry an estimate of p i j (t) = # daily accumulated percentage of inhabitants of i that travels to j. assuming that there is no correlation between the states and travels, we can assume that the population traveling population is uniform across states that is during the night. as workers come back to their city the model reduces to the standard seir model where cities do not interact and have their own population. full day cycle. because the work dynamics is mainly stereotyped and workers move in and out at well defined times we will approximate the dynamics movement as a step function. so all workers move out and come back at the same time. let α be a square pulse modeling this cycle, so that α(t) = when t is the range of working hours (here from am to pm) and zero otherwise. thus the model can be written as here we use t inc = . and t inf = . , following [ ] . as described in section . , we approximate the solution of the control problem by solving an optimization model. this model has the decision variables s i,t , e i,t , r i,t , i i,t , r i,t for i = , . . . , k and t = , . . . , t . the s , e, i, r variables represent the normalized seir states for all cities i at each day t. as for r i,t , it represents the respective target reproduction number that acts as the control variable. the value k is the number of cities and t is the desired time horizon for the simulation. . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. the copyright holder for this preprint this version posted may , . . https://doi.org/ . / . . . doi: medrxiv preprint we then solve min f (s , e, i, r, r) s.t. (s , e, i, r) ∈ dm(r) (s , e, i, r, r) ∈ oc s i,t + e i,t + i i,r + r i,t = , i = , . . . , k, t = , . . . , t where dm(r) is a discretized version of the the seir model for a given control r, as described in the last section, oc represents an abstract version of the operational constraints, that we detail below, and r is the natural reproduction number of covid- , that we approximated by . from [ ] . we used the modified euler method, also known as heun's method [ ] , to define dm(r). this is an explicit second order runge-kutta scheme that showed precise enough for our simulations. we used daily time steps. the operational constraints can be divided in two groups. first we add constraints ensuring that the controls have to remain constant in a time window. in the case studies the time window was days. this is desirable, as it is impossible to rapidly change the behavior of large populations. next we have constraints that limit the i variable at each day, using an estimate of number of intensive care units available for each city. another possibility would be to add this constraint aggregating the capacity by regions or even for the whole state, simulating situations where there is a single queue for the intensive care units. finally, the objective function f is composed of two terms that try to balance between two conflicting goals. the first term minimizes c= ,...,n t= ,...,t w t (r − r t ). the goal here is to try to avoid the use of mitigation measures, allowing normal life and economic activity. the weight w t balances the importance associated with keeping normal life at each city. in our case studies we used the square root of the city population to define these weight as a way to give more importance to large cities, if possible. the second term try to avoid employing the same controls for two different the cities at the same time − t= ,...,t i= ,...k j>i d(i, j, t)(r i,t − r j,t ) . the weights d(i, j, t) try to measure the importance keeping the cities i and j under different controls at each time t. we used a value proportional to the square root of the population of the smaller city and made it vanish by the end of the simulation, when the epidemic should be in natural decline. in both cases we used values proportional to the square of the population in avoid the large city of são paulo to fully dominate the decisions. finally one has to find weights that balance between those two (conflicting) constraints in order do define the single objective f . this framework is actually quite flexible. it allows for different terms to be added or deleted from the operational constraints oc or to the objective f . the only constraints that are essential are the ones in dm(r), since they approximate the seir dynamics. . cc-by . international license it is made available under a is the author/funder, who has granted medrxiv a license to display the preprint in perpetuity. 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