Do village-level normative and network factors help explain spatial variability in adolescent childbearing in rural Honduras?

Adolescent childbearing rates are higher in Central America than almost anywhere else. However, in this research we discovered that adolescent childbearing exhibits variability from one village to another, and we might discover factors associated with this spatial variability that can help us understand key characteristics underlying the pattern of early childbearing. To do this, we assessed the village-level normative and network factors associated with adolescent birth (birth taking place before age 20 years) in rural Honduras and evaluated the geographic dispersion of these patterns.

Monitoring forest cover change within different reserve types in southern Ghana.

Rapid population and economic growth quickly degrade and deplete forest resources in many developing countries, even within protected areas. Monitoring forest cover change is critical for assessing ecosystem changes and targeting conservation efforts. Yet the most biodiverse forests on the planet are also the most difficult to monitor remotely due to their frequent cloud cover.

A Pattern-Based Definition of Urban Context Using Remote Sensing and GIS.

In Sub-Saharan Africa rapid urban growth combined with rising poverty is creating diverse urban environments, the nature of which are not adequately captured by a simple urban-rural dichotomy. This paper proposes an alternative classification scheme for urban mapping based on a gradient approach for the southern portion of the West African country of Ghana. Landsat Enhanced Thematic Mapper Plus (ETM+) and European Remote Sensing Satellite-2 (ERS-2) synthetic aperture radar (SAR) imagery are used to generate a pattern based definition of the urban context.

A global systematic review of Chagas disease prevalence among migrants.

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 recent 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.

Agency, access, and Anopheles: neighborhood health perceptions and the implications for community health interventions in Accra, Ghana.

Background: Social and environmental factors are increasingly recognized for their ability to influence health outcomes at both individual and neighborhood scales in the developing urban world. Yet issues of spatial heterogeneity in these complex environments may obscure unique elements of neighborhood life that may be protective or harmful to human health. Resident perceptions of neighborhood effects on health may help to fill gaps in our interpretation of household survey results and better inform how to plan and execute neighborhood-level health interventions.

Estimating spatial inequalities of urban child mortality.

Background: Recent studies indicate that the traditional rural-urban dichotomy pointing to cities as places of better health in the developing world can be complicated by poverty differentials. Knowledge of spatial patterns is essential to understanding the processes that link individual demographic outcomes to characteristics of a place. A significant limitation, however, is the lack of spatial data and methods that offer flexibility in data inputs.

Histogram Curve Matching Approaches for Object-based Image Classification of Land Cover and Land Use.

The classification of image-objects is usually done using parametric statistical measures of central tendency and/or dispersion (e.g., mean or standard deviation).

Urban Vegetation Cover and Vegetation Change in Accra, Ghana: Connection to Housing Quality.

The objectives are to (1) quantify, map, and analyze vegetation cover distributions and changes across Accra, Ghana, for 2002 and 2010; and (2) examine the statistical relationship between vegetation cover and a housing quality index (HQI) for 2000 at the neighborhood level. Pixel-level vegetation cover maps derived using threshold classification of 2002 and 2010 QuickBird normalized difference vegetation index images have very high overall accuracies and yield an estimate of 5.9 percent vegetation cover reduction over the study area between 2002 and 2010.

Drinking Water in Transition: A Multilevel Cross-sectional Analysis of Sachet Water Consumption in Accra.

Rapid population growth in developing cities often outpaces improvements to drinking water supplies, and sub-Saharan Africa as a region has the highest percentage of urban population without piped water access, a figure that continues to grow. Accra, Ghana, implements a rationing system to distribute limited piped water resources within the city, and privately-vended sachet water-sealed single-use plastic sleeves-has filled an important gap in urban drinking water security. This study utilizes household survey data from 2,814 Ghanaian women to analyze the sociodemographic characteristics of those who resort to sachet water as their primary drinking water source.

Health, Poverty, and Place in Accra, Ghana: Mapping Neighborhoods.

The overall objective of our research project is to understand the spatial inequality in health in Accra, the capital city of Ghana. We also utilize GIS technology to measure the association of adverse health and mortality outcomes with neighborhood ecology. We approached this in variety of ways, including multivariate analysis of imagery classification and census data.

Income and health in Accra, Ghana: results from a time use and health study.

This paper uses newly collected household survey data from Accra, Ghana, to investigate whether incomes affect acute and chronic health outcomes in settings that can be considered representative for the large and rapidly growing urban centers of sub-Saharan Africa. The Time Use and Health Study in Accra collected information on incomes, current health status, and health care use from 5,484 persons in 1,250 households, each repeatedly sampled on a rolling basis for a period of 13 weeks. Data collection took place during September 2008-March 2010 to capture seasonal variations.

Do the Most Vulnerable People Live in the Worst Slums? A Spatial Analysis of Accra, Ghana.

Slums are examples of localized communities within third world urban systems representing a range of vulnerabilities and adaptive capacities. This study examines vulnerability in relation to flooding, environmental degradation, social-status, demographics, and health in the slums of Accra, Ghana by utilizing a place-based approach informed by fieldwork, remote sensing, census data, and geographically weighted regression. The study objectives are threefold: (1) to move slums from a dichotomous into a continuous classification and examine the spatial patterns of the gradient, (2) develop measures of vulnerability for a developing world city and model the relationship between slums and vulnerability, and (3) to assess if the most vulnerable individuals live in the worst slums.

Connecting the Dots Between Health, Poverty and Place in Accra, Ghana.

West Africa has a rapidly growing population, an increasing fraction of which lives in urban informal settlements characterized by inadequate infrastructure and relatively high health risks. Little is known, however, about the spatial or health characteristics of cities in this region or about the spatial inequalities in health within them. In this article we show how we have been creating a data-rich field laboratory in Accra, Ghana, to connect the dots between health, poverty, and place in a large city in West Africa.

Sachet drinking water in Ghana's Accra-Tema metropolitan area: past, present, and future.

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.

Assessing the Utility of Satellite Imagery with Differing Spatial Resolutions for Deriving Proxy Measures of Slum Presence in Accra, Ghana.

Little research has been conducted on how differing spatial resolutions or classification techniques affect image-driven identification and categorization of slum neighborhoods in developing nations. This study assesses the correlation between satellite-derived land cover and census-derived socioeconomic variables in Accra, Ghana to determine whether the relationship between these variables is altered with a change in spatial resolution or scale. ASTER and Landsat TM satellite images are each used to classify land cover using spectral mixture analysis (SMA), and land cover proportions are summarized across Enumeration Areas in Accra and compared to socioeconomic data for the same areas.

Spatial Epidemiology of HIV among Injection Drug Users in Tijuana, Mexico.

The northwest border city of Tijuana is Mexico's fifth largest and is experiencing burgeoning drug use and human immunodeficiency virus (HIV) epidemics. Since local geography influences disease risk, we explored the spatial distribution of HIV among injection drug users (IDUs). From 2006-2007, 1056 IDUs were recruited using respondent-driven sampling, and then followed for eighteen months.

Intraurban mobility and its potential impact on the spread of blood-borne infections among drug injectors in Tijuana, Mexico.

We explored intraurban mobility of Tijuana, Mexico, injection drug users (IDUs). In 2005, 222 IDUs underwent behavioral surveys and infectious disease testing. Participants resided in 58 neighborhoods, but regularly injected in 30.

When urban taps run dry: sachet water consumption and health effects in low income neighborhoods of Accra, Ghana.

Intraurban differentials in safe drinking water in developing cities have been exacerbated by rapid population growth that exceeds expansion of local water infrastructure. In Accra, Ghana, municipal water is rationed to meet demand, and the gap in water services is increasingly being filled by private water vendors selling packaged "sachet" water. Sachets extend drinking water coverage deeper into low-income areas and alleviate the need for safe water storage, potentially introducing a health benefit over stored tap water.

Exploring the relationships between dengue fever knowledge and breeding in St Catherine Parish, Jamaica: a pilot of enhanced low-cost surveillance.

Purpose: Dengue fever has re-emerged as an increasingly significant global health threat amid diminishing resources pledged for its control in developing nations. Efforts to limit breeding of the dengue vector are often hampered by lack of community awareness of the disease.

Methods: Sixty-eight households in St Catherine Parish, Jamaica completed a pilot knowledge, attitude, and practice questionnaire as part of a routine container survey for presence of larvae.

Adolescents' use of indoor tanning: a large-scale evaluation of psychosocial, environmental, and policy-level correlates.

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).

Geographic object-based delineation of neighborhoods of Accra, Ghana using QuickBird satellite imagery.

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: (1) merging adjacent EAs according to vegetation measures and (2) image segmentation. Both approaches exploit readily available functions within commercial GEOBIA software.

Neighborhoods and Fertility in Accra, Ghana: An AMOEBA-based Approach.

Fertility levels remain high in most of sub-Saharan Africa, despite recent declines, and even in a large capital city such as Accra, Ghana, women are having children at a pace that is well above replacement level and this will contribute to significant levels of future population growth in the city. Our purpose in this paper is to evaluate the way in which neighborhood context may shape reproductive behavior in Accra. In the process, we introduce several important innovations to the understanding of intra-urban fertility levels in a sub-Saharan African city: (1) despite the near explosion of work on neighborhoods as a spatial unit of analysis, very little of this research has been conducted outside of the richer countries; (2) we characterize neighborhoods on the basis of local knowledge of what we call "vernacular neighborhoods"; (3) we then define what we call "organic neighborhoods" using a new clustering tool-the AMOEBA algorithm-to create these neighborhoods; and then (4) we evaluate and explain which of the neighborhood concepts has the largest measurable contextual effect on an individual woman's reproductive behavior.

Distance threshold for the effect of urban agriculture on elevated self-reported malaria prevalence in Accra, Ghana.

Irrigated urban agriculture (UA), which has helped alleviate poverty and increase food security in rapidly urbanizing sub-Saharan Africa, may inadvertently support malaria vectors. Previous studies have not identified a variable distance effect on malaria prevalence from UA. This study examines the relationships between self-reported malaria information for 3,164 women surveyed in Accra, Ghana, in 2003, and both household characteristics and proximity to sites of UA.

Density of indoor tanning facilities in 116 large U.S. cities.

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.

Correlates of tanning facility prevalence within San Diego County, California census tracts.

Adolescents frequenting indoor tanning facilities may have an increased risk of skin cancer. The high level of indoor tanning by this age group may be due, in part, to the large number of tanning facilities in US cities. This study examined how facilities are distributed throughout one large county.