John Weeks - Academia.edu (original) (raw)

Papers by John Weeks

Journal of Global Health, Mar 30, 2020

Journal of Maps, Nov 15, 2012

Journal of Water Sanitation and Hygiene for Development, Dec 1, 2012

Population growth in West Africa has outpaced local efforts to expand potable water services, and... more Population growth in West Africa has outpaced local efforts to expand potable water services, and private sector sale of packaged drinking water has filled an important gap in household water security. Consumption of drinking water packaged in plastic sachets has soared in West Africa over the last decade, but the long-term implications of these changing consumption patterns remain unclear and unstudied. This paper reviews recent shifts in drinking water, drawing upon data from the 2003 and 2008 Demographic and Health Surveys, and provides an overview of the history, economics, quality, and regulation of sachet water in Ghana's Accra-Tema Metropolitan Area. Given the pros and cons of sachet water, we suggest that a more holistic understanding of the drinking water landscape is necessary for municipal planning and sustainable drinking water provision.

Remote Sensing, Dec 16, 2011

The goal of this study was to map and quantify the number of newly constructed buildings in Accra... more The goal of this study was to map and quantify the number of newly constructed buildings in Accra, Ghana between 2002 and 2010 based on high spatial resolution satellite image data. Two semi-automated feature detection approaches for detecting and mapping newly constructed buildings based on QuickBird very high spatial resolution satellite imagery were analyzed: (1) post-classification comparison; and (2) bi-temporal layerstack classification. Feature Analyst software based on a spatial contextual classifier and ENVI Feature Extraction that uses a true object-based image analysis approach of image segmentation and segment classification were evaluated. Final map products representing new building objects were compared and assessed for accuracy using two object-based accuracy measures, completeness and correctness. The bi-temporal layerstack method generated more accurate results compared to the post-classification comparison method due to less confusion with background objects. The spectral/spatial contextual approach (Feature Analyst) outperformed the true object-based feature delineation approach (ENVI Feature Extraction) due to its ability to more reliably delineate individual buildings of various sizes. Semi-automated, object-based detection followed by manual editing appears to be a reliable and efficient approach for detecting and enumerating new building objects. A bivariate regression analysis was performed using neighborhood-level estimates of new building density regressed on a census-derived measure of socioeconomic status, yielding an inverse relationship with R 2 = 0.31 (n = 27; p = 0.00). The primary utility of the new building delineation results is to support spatial analyses of land cover and land use and demographic change.

Social Science Research Network, 1999

... Selectivity Hypothesis John R. Weeks,1,4 Ruben G. Rumbaut,2 and Norma Ojeda3 ... (16) We sele... more ... Selectivity Hypothesis John R. Weeks,1,4 Ruben G. Rumbaut,2 and Norma Ojeda3 ... (16) We selected for analysis those women whose purpose in coming to the hospital was to deliver a child, and for whom the outcome was a singleton live birth. ...

OBJECTIVES We evaluated psychosocial, built-environmental, and policy-related correlates of adole... more OBJECTIVES We evaluated psychosocial, built-environmental, and policy-related correlates of adolescents' indoor tanning use. METHODS We developed 5 discrete data sets in the 100 most populous US cities, based on interviews of 6125 adolescents (aged 14-17 years) and their parents, analysis of state indoor tanning laws, interviews with enforcement experts, computed density of tanning facilities, and evaluations of these 3399 facilities' practices regarding access by youths. After univariate analyses, we constructed multilevel models with generalized linear mixed models (GLMMs). RESULTS In the past year, 17.1% of girls and 3.2% of boys had used indoor tanning. The GLMMs indicated that several psychosocial or demographic variables significantly predicted use, including being female, older, and White; having a larger allowance and a parent who used indoor tanning and allowed their adolescent to use it; and holding certain beliefs about indoor tanning's consequences. Living within 2 miles of a tanning facility also was a significant predictor. Residing in a state with youth-access legislation was not significantly associated with use. CONCLUSIONS Current laws appear ineffective in reducing indoor tanning; bans likely are needed. Parents have an important role in prevention efforts.

Population Space and Place, Apr 5, 2017

Sub-Saharan Africa has the highest levels of fertility in the world, despite rapid urban growth i... more Sub-Saharan Africa has the highest levels of fertility in the world, despite rapid urban growth in most nations of the region. While there are many reasons for the fact that fertility decline is slow in Africa, we hypothesize that the relationship between fertility and urbanization is obscured by the fact that urbanization takes place along a gradient. In the most urban places (e.g., neighborhoods of the largest cities), fertility is apt to be very low, but most urban residents are residing in places that are somewhere along a continuum from completely rural to the most urban possible. All previous attempts to define that urban gradient and relate it to fertility levels rely in one form or another on census data. Because sub-Saharan-African countries are among the least prolific in terms of census gathering, a measure that relies solely on satellite imagery to gage a place's position along the urban gradient could be extremely useful. This paper describes a methodology for doing this and then uses data from the West African country of Ghana to examine how spatial patterns of land cover are associated with fertility. Satellite imagery and landscape metrics are used to create an urban context definition based on landscape patterns using a gradient approach. Census data are used to model the association between urban context and fertility through ordinary least square regression and spatial autoregressive models. Results indicate that there are significant differences in fertility between different urban contexts.

Social Science Research Network, 1996

ABSTRACT Research has pointed to an apparent public health enigma among new immigrants to the Uni... more ABSTRACT Research has pointed to an apparent public health enigma among new immigrants to the United States: high-risk groups, particularly low-income immigrants from Mexico and Southeast Asia, show unexpectedly favorable perinatal outcomes and seem to be “superior health achievers.” This study attempts to unravel the reasons for this “epidemiological paradox” by examining an in-depth data set drawn from a Comprehensive Perinatal Program (CPP) in San Diego County providing prenatal care services to low-income pregnant women, most of whom were immigrants from Mexico and various Asian countries, The CPP data set consists of nearly 500 independent variables per case (including most of those listed in the research literature as likely biomedical and sociocultural determinants of pregnancy outcomes) for a sample of both foreign-born and U.S.-born women, matched to infant health outcome measures collected from hospital records for every baby delivered by CPP mothers during 1989-1991. The analysis focuses on the identification of maternal risk factors that best explain observed ethnic and/or nativity differences in pregnancy outcomes (birth weight, diagnoses at birth, complications, length of hospitalization of the baby). Asians and Hispanics (mostly foreign-born) had superior outcomes relative to Anglos and African-Americans (mostly native-born); within ethnic groups outcomes were generally better for immigrants than for natives; and for immigrants outcomes worsened as the general acculturation or “Americanization” of the mother increased. The comparative socioeconomic advantages of US-born women – in education, employment, income, English literacy and proficiency – appeared to be overwhelmed by biomedical, nutritional and psychosocial disadvantages. In multivariate analyses, ten independent variables – a set of both biomedical and sociocultural factors – remained as significant predictors of pregnancy outcomes. Four qualitative case histories of CPP mothers are drawn from psychosocial reports to shed further light on the quantitative findings drawn from the statistical analysis. Limitations and implications of this study for health policy and future research are considered.

PubMed, Mar 1, 1989

From 1975 to 1988, nearly 900,000 Indochinese refugees were resettled in the United States. This ... more From 1975 to 1988, nearly 900,000 Indochinese refugees were resettled in the United States. This paper examines patterns of fertility among these refugees from Cambodia, Laos, and Vietnam who have exhibited high levels of reproduction since their arrival. Data are drawn from sample surveys in San Diego and San Francisco, CA. Fertility levels were found to exceed five children per ever-married woman, a level that is consistent with perceptions of ideal family size in the homeland. Fertility levels were significantly higher among rural second-wave refugees than in the more urban first-wave groups. One explanation for the high fertility is that couples have migrated from areas where fertility is high, and they have not yet adapted their reproductive behavior to the low fertility environment of the United States. This possibility is reinforced by a general gender preference for boys and exacerbated by the fact that, while a majority of women are aware of methods of fertility control, access is still limited by cultural and financial barriers, and the motivation to use family planning still appears to be relatively low. The data suggest that this refugee population will continue to put pressure on maternal and child health resources, and that continued residence in the United States could lead to desires to limit family size, thus increasing demand for methods of fertility control.

American Journal of Preventive Medicine, Mar 1, 2009

Background-U.S. adolescents and young adults are using indoor tanning at high rates, even though ... more Background-U.S. adolescents and young adults are using indoor tanning at high rates, even though it has been linked to both melanoma and squamous cell cancer. Because the availability of commercial indoor tanning facilities may influence use, data are needed on the number and density of such facilities. Methods-In March 2006, commercial indoor tanning facilities in 116 large U.S. cities were identified, and the number and density (per 100,000 population) were computed for each city. Bivariate and multivariate analyses conducted in 2008 tested the association between tanning-facility density and selected geographic, climatologic, demographic, and legislative variables. Results-Mean facility number and density across cities were 41.8 (SD=30.8) and 11.8 (SD=6.0), respectively. In multivariate analysis, cities with higher percentages of whites and lower ultraviolet (UV)index scores had significantly higher facility densities than those with lower percentages of whites and higher UV index scores. Conclusions-These data indicate that commercial indoor tanning is widely available in the urban U.S., and this availability may help explain the high usage of indoor tanning.

International Migration Review, 1986

Acta Tropica, Apr 1, 2016

Human migration has been identified as a potential factor for increased Chagas disease risk and h... more Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize current seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas in migrants, especially among intra-regional migrants within Latin America. Given that the disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease.

Choice Reviews Online, Sep 1, 2011

The politics, social issues, and cultural impacts of Latin American migration to the United State... more The politics, social issues, and cultural impacts of Latin American migration to the United States are often studied by historians and political scientists, but the regional focus is typically on the Southwest and California. This study examines the phenomenon of the impact of Latin American migration on the southeastern United States, a region that now has the nation's fastest growing immigrant population.Incorporating a political demography approach, this study seeks to provide a clear understanding of the complex dynamics of migration with particular emphasis on the unique demographic "fit" between the United States and Latin America. This fit arises from one region needing young workers while the other has more than its economy can absorb. Although a relatively simple concept, it is one that has largely been ignored in the political discussions of migration policy. This study argues that the social and political ramifications of and policy responses to Latin American immigration can best be understood when viewed in light of these circumstances.

Photogrammetric Engineering and Remote Sensing, Aug 1, 2010

The objective was to test GEographic Object-based Image Analysis (GEOBIA) techniques for delineat... more The objective was to test GEographic Object-based Image Analysis (GEOBIA) techniques for delineating neighborhoods of Accra, Ghana using QuickBird multispectral imagery. Two approaches to aggregating census enumeration areas (EAs) based on image-derived measures of vegetation objects were tested: (a) merging adjacent EAs according to vegetation measures, and (b) image segmentation. Both approaches exploit readily available functions within commercial GEOBIA software. Image-derived neighborhood maps were compared to a reference map derived by spatial clustering of slum index values (from census data), to provide a relative assessment of potential map utility. A size-constrained iterative segmentation approach to aggregation was more successful than standard image segmentation or feature merge techniques. The segmentation approaches account for size and shape characteristics, enabling more realistic neighborhood boundaries to be delineated. The percentage of vegetation patches within each EA yielded more realistic delineation of potential neighborhoods than mean vegetation patch size per EA.

Research in the sociology of health care, 1989

ABSTRACT This article presents detailed comparative analyses of infant health outcomes and risk f... more ABSTRACT This article presents detailed comparative analyses of infant health outcomes and risk factors among refugee groups from Vietnam, Laos and Cambodia, compared to all other major racial-ethnic groups in San Diego County, California (Hispanics, non-Hispanic whites and blacks, Filipinos, Chinese, Japanese, and American Indians). Data are drawn from (1) a complete list of all linked live births (N=269,252) and infant deaths (N=2,610) recorded in San Diego County from 1978 to 1985; (2) longitudinal survey data from refugee respondents in the Indochinese Health and Adaptation Research Project (IHARP), matched to the vital statistics data; and (3) in-depth qualitative interviews which were conducted with a subsample of refugee mothers about their pregnancies since their arrival in the United States. Findings measure early neonatal and post-early neonatal infant mortality rates for all groups, as well as birth weight (in grams), low-birthweight births, late onset of prenatal care, and other risk factors. Multivariate analyses of the vital statistics and the longitudinal survey data identify the determinants of infant health outcomes, while four detailed case histories of Hmong and Vietnamese refugee mothers are sketched from the qualitative data. Despite severe economic and cultural handicaps and traumatic migration histories, Indochinese refugees were found to exhibit significantly lower infant mortality rates than more advantaged groups, another instance of the, “epidemiological paradox,” also observed among Mexican immigrants. Theoretical and policy implications of these findings are discussed.

Journal of Global Health, Mar 30, 2020

Journal of Maps, Nov 15, 2012

Journal of Water Sanitation and Hygiene for Development, Dec 1, 2012

Population growth in West Africa has outpaced local efforts to expand potable water services, and... more Population growth in West Africa has outpaced local efforts to expand potable water services, and private sector sale of packaged drinking water has filled an important gap in household water security. Consumption of drinking water packaged in plastic sachets has soared in West Africa over the last decade, but the long-term implications of these changing consumption patterns remain unclear and unstudied. This paper reviews recent shifts in drinking water, drawing upon data from the 2003 and 2008 Demographic and Health Surveys, and provides an overview of the history, economics, quality, and regulation of sachet water in Ghana's Accra-Tema Metropolitan Area. Given the pros and cons of sachet water, we suggest that a more holistic understanding of the drinking water landscape is necessary for municipal planning and sustainable drinking water provision.

Remote Sensing, Dec 16, 2011

The goal of this study was to map and quantify the number of newly constructed buildings in Accra... more The goal of this study was to map and quantify the number of newly constructed buildings in Accra, Ghana between 2002 and 2010 based on high spatial resolution satellite image data. Two semi-automated feature detection approaches for detecting and mapping newly constructed buildings based on QuickBird very high spatial resolution satellite imagery were analyzed: (1) post-classification comparison; and (2) bi-temporal layerstack classification. Feature Analyst software based on a spatial contextual classifier and ENVI Feature Extraction that uses a true object-based image analysis approach of image segmentation and segment classification were evaluated. Final map products representing new building objects were compared and assessed for accuracy using two object-based accuracy measures, completeness and correctness. The bi-temporal layerstack method generated more accurate results compared to the post-classification comparison method due to less confusion with background objects. The spectral/spatial contextual approach (Feature Analyst) outperformed the true object-based feature delineation approach (ENVI Feature Extraction) due to its ability to more reliably delineate individual buildings of various sizes. Semi-automated, object-based detection followed by manual editing appears to be a reliable and efficient approach for detecting and enumerating new building objects. A bivariate regression analysis was performed using neighborhood-level estimates of new building density regressed on a census-derived measure of socioeconomic status, yielding an inverse relationship with R 2 = 0.31 (n = 27; p = 0.00). The primary utility of the new building delineation results is to support spatial analyses of land cover and land use and demographic change.

Social Science Research Network, 1999

... Selectivity Hypothesis John R. Weeks,1,4 Ruben G. Rumbaut,2 and Norma Ojeda3 ... (16) We sele... more ... Selectivity Hypothesis John R. Weeks,1,4 Ruben G. Rumbaut,2 and Norma Ojeda3 ... (16) We selected for analysis those women whose purpose in coming to the hospital was to deliver a child, and for whom the outcome was a singleton live birth. ...

OBJECTIVES We evaluated psychosocial, built-environmental, and policy-related correlates of adole... more OBJECTIVES We evaluated psychosocial, built-environmental, and policy-related correlates of adolescents' indoor tanning use. METHODS We developed 5 discrete data sets in the 100 most populous US cities, based on interviews of 6125 adolescents (aged 14-17 years) and their parents, analysis of state indoor tanning laws, interviews with enforcement experts, computed density of tanning facilities, and evaluations of these 3399 facilities' practices regarding access by youths. After univariate analyses, we constructed multilevel models with generalized linear mixed models (GLMMs). RESULTS In the past year, 17.1% of girls and 3.2% of boys had used indoor tanning. The GLMMs indicated that several psychosocial or demographic variables significantly predicted use, including being female, older, and White; having a larger allowance and a parent who used indoor tanning and allowed their adolescent to use it; and holding certain beliefs about indoor tanning's consequences. Living within 2 miles of a tanning facility also was a significant predictor. Residing in a state with youth-access legislation was not significantly associated with use. CONCLUSIONS Current laws appear ineffective in reducing indoor tanning; bans likely are needed. Parents have an important role in prevention efforts.

Population Space and Place, Apr 5, 2017

Sub-Saharan Africa has the highest levels of fertility in the world, despite rapid urban growth i... more Sub-Saharan Africa has the highest levels of fertility in the world, despite rapid urban growth in most nations of the region. While there are many reasons for the fact that fertility decline is slow in Africa, we hypothesize that the relationship between fertility and urbanization is obscured by the fact that urbanization takes place along a gradient. In the most urban places (e.g., neighborhoods of the largest cities), fertility is apt to be very low, but most urban residents are residing in places that are somewhere along a continuum from completely rural to the most urban possible. All previous attempts to define that urban gradient and relate it to fertility levels rely in one form or another on census data. Because sub-Saharan-African countries are among the least prolific in terms of census gathering, a measure that relies solely on satellite imagery to gage a place's position along the urban gradient could be extremely useful. This paper describes a methodology for doing this and then uses data from the West African country of Ghana to examine how spatial patterns of land cover are associated with fertility. Satellite imagery and landscape metrics are used to create an urban context definition based on landscape patterns using a gradient approach. Census data are used to model the association between urban context and fertility through ordinary least square regression and spatial autoregressive models. Results indicate that there are significant differences in fertility between different urban contexts.

Social Science Research Network, 1996

ABSTRACT Research has pointed to an apparent public health enigma among new immigrants to the Uni... more ABSTRACT Research has pointed to an apparent public health enigma among new immigrants to the United States: high-risk groups, particularly low-income immigrants from Mexico and Southeast Asia, show unexpectedly favorable perinatal outcomes and seem to be “superior health achievers.” This study attempts to unravel the reasons for this “epidemiological paradox” by examining an in-depth data set drawn from a Comprehensive Perinatal Program (CPP) in San Diego County providing prenatal care services to low-income pregnant women, most of whom were immigrants from Mexico and various Asian countries, The CPP data set consists of nearly 500 independent variables per case (including most of those listed in the research literature as likely biomedical and sociocultural determinants of pregnancy outcomes) for a sample of both foreign-born and U.S.-born women, matched to infant health outcome measures collected from hospital records for every baby delivered by CPP mothers during 1989-1991. The analysis focuses on the identification of maternal risk factors that best explain observed ethnic and/or nativity differences in pregnancy outcomes (birth weight, diagnoses at birth, complications, length of hospitalization of the baby). Asians and Hispanics (mostly foreign-born) had superior outcomes relative to Anglos and African-Americans (mostly native-born); within ethnic groups outcomes were generally better for immigrants than for natives; and for immigrants outcomes worsened as the general acculturation or “Americanization” of the mother increased. The comparative socioeconomic advantages of US-born women – in education, employment, income, English literacy and proficiency – appeared to be overwhelmed by biomedical, nutritional and psychosocial disadvantages. In multivariate analyses, ten independent variables – a set of both biomedical and sociocultural factors – remained as significant predictors of pregnancy outcomes. Four qualitative case histories of CPP mothers are drawn from psychosocial reports to shed further light on the quantitative findings drawn from the statistical analysis. Limitations and implications of this study for health policy and future research are considered.

PubMed, Mar 1, 1989

From 1975 to 1988, nearly 900,000 Indochinese refugees were resettled in the United States. This ... more From 1975 to 1988, nearly 900,000 Indochinese refugees were resettled in the United States. This paper examines patterns of fertility among these refugees from Cambodia, Laos, and Vietnam who have exhibited high levels of reproduction since their arrival. Data are drawn from sample surveys in San Diego and San Francisco, CA. Fertility levels were found to exceed five children per ever-married woman, a level that is consistent with perceptions of ideal family size in the homeland. Fertility levels were significantly higher among rural second-wave refugees than in the more urban first-wave groups. One explanation for the high fertility is that couples have migrated from areas where fertility is high, and they have not yet adapted their reproductive behavior to the low fertility environment of the United States. This possibility is reinforced by a general gender preference for boys and exacerbated by the fact that, while a majority of women are aware of methods of fertility control, access is still limited by cultural and financial barriers, and the motivation to use family planning still appears to be relatively low. The data suggest that this refugee population will continue to put pressure on maternal and child health resources, and that continued residence in the United States could lead to desires to limit family size, thus increasing demand for methods of fertility control.

American Journal of Preventive Medicine, Mar 1, 2009

Background-U.S. adolescents and young adults are using indoor tanning at high rates, even though ... more Background-U.S. adolescents and young adults are using indoor tanning at high rates, even though it has been linked to both melanoma and squamous cell cancer. Because the availability of commercial indoor tanning facilities may influence use, data are needed on the number and density of such facilities. Methods-In March 2006, commercial indoor tanning facilities in 116 large U.S. cities were identified, and the number and density (per 100,000 population) were computed for each city. Bivariate and multivariate analyses conducted in 2008 tested the association between tanning-facility density and selected geographic, climatologic, demographic, and legislative variables. Results-Mean facility number and density across cities were 41.8 (SD=30.8) and 11.8 (SD=6.0), respectively. In multivariate analysis, cities with higher percentages of whites and lower ultraviolet (UV)index scores had significantly higher facility densities than those with lower percentages of whites and higher UV index scores. Conclusions-These data indicate that commercial indoor tanning is widely available in the urban U.S., and this availability may help explain the high usage of indoor tanning.

International Migration Review, 1986

Acta Tropica, Apr 1, 2016

Human migration has been identified as a potential factor for increased Chagas disease risk and h... more Human migration has been identified as a potential factor for increased Chagas disease risk and has transformed the disease from a Latin American problem to a global one. We conducted a systematic review of the scientific literature between 2004-2014 in order to: summarize current seroprevalence estimates of Chagas disease among Latin American migrants, in both endemic and non-endemic settings; compare seroprevalence estimates in migrants to countrywide prevalence estimates; and identify risk factors for Chagas disease among migrants. A total of 320 studies were screened and 23 studies were included. We found evidence that the prevalence of Chagas disease is higher than expected in some migrant groups and that reliance on blood donor screening prevalence underestimates the burden of disease. Overall there is a dearth of high quality epidemiologic studies on the prevalence of Chagas in migrants, especially among intra-regional migrants within Latin America. Given that the disease cannot likely be eradicated, improved surveillance and reporting is vital to continuing control efforts. More accurate health surveillance of both Latin American migrants and the Chagas disease burden will help countries appropriately scale up their response to this chronic disease. Overall, improved estimates of Chagas disease among migrants would likely serve to highlight the real need for better screening, diagnostics, and treatment of individuals living with the disease.

Choice Reviews Online, Sep 1, 2011

The politics, social issues, and cultural impacts of Latin American migration to the United State... more The politics, social issues, and cultural impacts of Latin American migration to the United States are often studied by historians and political scientists, but the regional focus is typically on the Southwest and California. This study examines the phenomenon of the impact of Latin American migration on the southeastern United States, a region that now has the nation's fastest growing immigrant population.Incorporating a political demography approach, this study seeks to provide a clear understanding of the complex dynamics of migration with particular emphasis on the unique demographic "fit" between the United States and Latin America. This fit arises from one region needing young workers while the other has more than its economy can absorb. Although a relatively simple concept, it is one that has largely been ignored in the political discussions of migration policy. This study argues that the social and political ramifications of and policy responses to Latin American immigration can best be understood when viewed in light of these circumstances.

Photogrammetric Engineering and Remote Sensing, Aug 1, 2010

The objective was to test GEographic Object-based Image Analysis (GEOBIA) techniques for delineat... more The objective was to test GEographic Object-based Image Analysis (GEOBIA) techniques for delineating neighborhoods of Accra, Ghana using QuickBird multispectral imagery. Two approaches to aggregating census enumeration areas (EAs) based on image-derived measures of vegetation objects were tested: (a) merging adjacent EAs according to vegetation measures, and (b) image segmentation. Both approaches exploit readily available functions within commercial GEOBIA software. Image-derived neighborhood maps were compared to a reference map derived by spatial clustering of slum index values (from census data), to provide a relative assessment of potential map utility. A size-constrained iterative segmentation approach to aggregation was more successful than standard image segmentation or feature merge techniques. The segmentation approaches account for size and shape characteristics, enabling more realistic neighborhood boundaries to be delineated. The percentage of vegetation patches within each EA yielded more realistic delineation of potential neighborhoods than mean vegetation patch size per EA.

Research in the sociology of health care, 1989

ABSTRACT This article presents detailed comparative analyses of infant health outcomes and risk f... more ABSTRACT This article presents detailed comparative analyses of infant health outcomes and risk factors among refugee groups from Vietnam, Laos and Cambodia, compared to all other major racial-ethnic groups in San Diego County, California (Hispanics, non-Hispanic whites and blacks, Filipinos, Chinese, Japanese, and American Indians). Data are drawn from (1) a complete list of all linked live births (N=269,252) and infant deaths (N=2,610) recorded in San Diego County from 1978 to 1985; (2) longitudinal survey data from refugee respondents in the Indochinese Health and Adaptation Research Project (IHARP), matched to the vital statistics data; and (3) in-depth qualitative interviews which were conducted with a subsample of refugee mothers about their pregnancies since their arrival in the United States. Findings measure early neonatal and post-early neonatal infant mortality rates for all groups, as well as birth weight (in grams), low-birthweight births, late onset of prenatal care, and other risk factors. Multivariate analyses of the vital statistics and the longitudinal survey data identify the determinants of infant health outcomes, while four detailed case histories of Hmong and Vietnamese refugee mothers are sketched from the qualitative data. Despite severe economic and cultural handicaps and traumatic migration histories, Indochinese refugees were found to exhibit significantly lower infant mortality rates than more advantaged groups, another instance of the, “epidemiological paradox,” also observed among Mexican immigrants. Theoretical and policy implications of these findings are discussed.

This article presents detailed comparative analyses of infant health outcomes and risk factors am... more This article presents detailed comparative analyses of infant health outcomes and risk factors among refugee groups from Vietnam, Laos and Cambodia, compared to all other major racial-ethnic groups in San Diego County, California (Hispanics, non-Hispanic whites and blacks, Filipinos, Chinese, Japanese, and American Indians). Data are drawn from (1) a complete list of all linked live births (N=269,252) and infant deaths (N=2,610) recorded in San Diego County from 1978 to 1985; (2) longitudinal survey data from refugee respondents in the Indochinese Health and Adaptation Research Project (IHARP), matched to the vital statistics data; and (3) in-depth qualitative interviews which were conducted with a subsample of refugee mothers about their pregnancies since their arrival in the United States. Findings measure early neonatal and post-early neonatal infant mortality rates for all groups, as well as birth weight (in grams), low-birthweight births, late onset of prenatal care, and other risk factors. Multivariate analyses of the vital statistics and the longitudinal survey data identify the determinants of infant health outcomes, while four detailed case histories of Hmong and Vietnamese refugee mothers are sketched from the qualitative data. Despite severe economic and cultural handicaps and traumatic migration histories, Indochinese refugees were found to exhibit significantly lower infant mortality rates than more advantaged groups, another instance of the, “epidemiological paradox,” also observed among Mexican immigrants. Theoretical and policy implications of these findings are discussed.