556 research outputs found

    Spatial Associations Between Contaminated Land and Socio Demographics in Ghana

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    Associations between contaminated land and socio demographics are well documented in high-income countries. In low- and middle-income countries, however, little is known about the extent of contaminated land and possible demographic correlations. This is an important yet sparsely researched topic with potentially significant public health implications as exposure to pollution remains a leading source of morbidity and mortality in low-income countries. In this study, we review the associations between several socio demographic factors (population, population density, unemployment, education, and literacy) and contaminated sites in Ghana. Within this context, both correlation and association intend to show the relationship between two variables, namely contaminated sites and socio demographics. Aggregated district level 2010 census data from Ghana Statistical Service and contaminated site location data from Pure Earth’s Toxic Sites Identification Program (TSIP) were spatially evaluated using the number of sites per kilometer squared within districts as the unit of measurement. We found a low to medium positive correlation (ρ range: 0.285 to 0.478) between contaminated sites and the following socio demographics: higher population density, higher unemployment, greater education, and higher literacy rate. These results support previous studies and suggest that several socio demographic factors may be reasonably accurate predictors of contaminated site locations. More research and targeted data collection is needed to better understand these associations with the ultimate goal of developing a predictive model

    Burden of disease resulting from lead exposure at toxic waste sites in Argentina, Mexico and Uruguay

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    Background: Though lead contaminated waste sites have been widely researched in many high-income countries, their prevalence and associated health outcomes have not been well documented in low- and middle-income countries. Methods: Using the well-established health metric disability-adjusted life year (DALY) and an exposure assessment method developed by Chatham-Stephens et al., we estimated the burden of disease resulting from exposure to lead at toxic waste sites in three Latin American countries in 2012: Argentina, Mexico and Uruguay. Toxic waste sites identified through Pure Earth’s Toxic Sites Identification Program (TSIP) were screened for lead in both biological and environmental sample media. Estimates of cardiovascular disease incidence and other outcomes resulting from exposure to lead were utilized to estimate DALYs for each population at risk. Results: Approximately 316,703 persons in three countries were at risk of exposure to pollutants at 129 unique sites identified through the TSIP database. Exposure to lead was estimated to result in between 51,432 and 115,042 DALYs, depending on the weighting factor used. The estimated burden of disease caused by exposure to lead in this analysis is comparable to that estimated for Parkinson’s disease and bladder cancer in these countries. Conclusions: Lead continues to pose a significant public health risk in Argentina, Mexico, and Uruguay. The burden of disease in these three countries is comparable with other widely recognized public health challenges. Knowledge of the relatively high number of DALYs associated with lead exposure may be used to generate support and funding for the remediation of toxic waste sites in these countries and others

    A Simplified Risk-Ranking System for Prioritizing Toxic Pollution Sites in Low- and Middle-Income Countries

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    Background: In low- and middle-income countries (LMICs), chemical exposures in the environment due to hazardous waste sites and toxic pollutants are typically poorly documented and their health impacts insufficiently quantified. Furthermore, there often is only limited understanding of the health and environmental consequences of point source pollution problems, and little consensus on how to assess and rank them. The contributions of toxic environmental exposures to the global burden of disease are not well characterized. Objectives: The aim of this study was to describe the simple but effective approach taken by Blacksmith Institute’s Toxic Sites Identification Program to quantify and rank toxic exposures in LMICs. This system is already in use at more than 3000 sites in 48 countries such as India, Indonesia, China, Ghana, Kenya, Tanzania, Peru, Bolivia, Argentina, Uruguay, Armenia, Azerbaijan, and Ukraine. Methods: A hazard ranking system formula, the Blacksmith Index (BI), takes into account important factors such as the scale of the pollution source, the size of the population possibly affected, and the exposure pathways, and is designed for use reliably in low-resource settings by local personnel provided with limited training. Findings: Four representative case studies are presented, with varying locations, populations, pollutants, and exposure pathways. The BI was successfully applied to assess the extent and severity of environmental pollution problems at these sites. Conclusions: The BI is a risk-ranking tool that provides direct and straightforward characterization, quantification, and prioritization of toxic pollution sites in settings where time, money, or resources are limited. It will be an important and useful tool for addressing toxic pollution problems in LMICs. Although the BI does not have the sophistication of the US Environmental Protection Agency’s Hazard Ranking System, the case studies presented here document the effectiveness of the BI in the field, especially in low-resource settings. Understanding of the risks posed by toxic pollution sites helps assure better use of resources to manage sites and mitigate risks to public health. Quantification of these hazards is an important input to assessments of the global burden of disease

    A cross-sectional study of differences in 6-min walk distance in healthy adults residing at high altitude versus sea level

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    BACKGROUND: We sought to determine if adult residents living at high altitude have developed sufficient adaptation to a hypoxic environment to match the functional capacity of a similar population at sea level. To test this hypothesis, we compared the 6-min walk test distance (6MWD) in 334 residents living at sea level vs. at high altitude. METHODS: We enrolled 168 healthy adults aged ≥35 years residing at sea level in Lima and 166 individuals residing at 3,825 m above sea level in Puno, Peru. Participants completed a 6-min walk test, answered a sociodemographics and clinical questionnaire, underwent spirometry, and a blood test. RESULTS: Average age was 54.0 vs. 53.8 years, 48% vs. 43% were male, average height was 155 vs. 158 cm, average blood oxygen saturation was 98% vs. 90%, and average resting heart rate was 67 vs. 72 beats/min in Lima vs. Puno. In multivariable regression, participants in Puno walked 47.6 m less (95% CI -81.7 to -13.6 m; p < 0.01) than those in Lima. Other variables besides age and height that were associated with 6MWD include change in heart rate (4.0 m per beats/min increase above resting heart rate; p < 0.001) and percent body fat (-1.4 m per % increase; p = 0.02). CONCLUSIONS: The 6-min walk test predicted a lowered functional capacity among Andean high altitude vs. sea level natives at their altitude of residence, which could be explained by an incomplete adaptation or a protective mechanism favoring neuro- and cardioprotection over psychomotor activity

    Estimating the Prevalence of Toxic Waste Sites in Low- and Middle-Income Countries

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    BackgroundExposure to heavy metals at contaminated industrial and mining sites, known also as hot spots, is a significant source of toxic exposure and adverse health outcomes in countries around the world. The Toxic Sites Identification Program (TSIP) developed by Pure Earth, a New York–based nongovernmental organization, is the only systematic effort to catalogue contaminated sites globally. To date, TSIP has identified and catalogued 3282 sites in low- and middle-income countries. The TSIP methodology is not designed to survey all contaminated sites in a country. Rather sites are prioritized based on their perceived impact on human health, and only a limited number of the most highly hazardous sites are surveyed. The total number of contaminated sites globally and the fraction of contaminated sites captured by TSIP is not known.ObjectiveTo determine the TSIP site capture rate, the fraction of contaminated sites in a country catalogued by TSIP.MethodsGhana was selected for this analysis because it is a rapidly industrializing lower middle income country with a heterogeneous industrial base, a highly urban population (51%), and good public records systems. To develop an estimate of the fraction of sites in Ghana captured by TSIP, assessors targeted randomly selected geographic quadrats for comprehensive assessment using area and population statistics from the Ghana Statistical Service. Investigators physically walked all accessible streets in each quadrat to visually identify all sites. Visual identification was supplemented by field-based confirmation with portable x-ray fluorescence instruments to test soils for metals. To extrapolate from survey findings to develop a range of estimates for the entire country, the investigators used 2 methodologies: a “bottom-up” approach that first estimated the number of waste sites in each region and then summed these regional subtotals to develop a total national estimate; and a “top-down” method that estimated the total number of sites in Ghana and then allocated these sites to each region. Both methods used cluster random sampling principles.FindingsThe investigators identified 72 sites in the sampled quadrats. Extrapolating from these findings to the entire country, the first methodology estimated that there are 1561 sites contaminated by heavy metals in Ghana (confidence interval [CI]: 1134-1987), whereas the second estimated 1944 sites (CI: 812-3075). The estimated total number of contaminated sites in Ghana is thus 7-9 times the number of sites captured through TSIP. On a population basis, it was estimated that there are between 31 and 115 contaminated sites per million inhabitants in Ghana.ConclusionsThe findings of this study indicate that the TSIP methodology provides a sound statistical basis for policy formulation. The statistical approaches used in this study can be replicated in other countries to improve estimates of the prevalence of contaminated sites. This information provides important input to calculations of the global burden of disease attributable to hazardous exposures at contaminated sites

    Engagement in a Public Forum: Knowledge, Action, and Cosmopolitanism

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    Facing challenges to the civic purpose of higher education, some scholars and administrators turn to the rhetoric of engagement. Simultaneously, the political philosophy of cosmopolitanism has gained intellectual favor, advocating openness to the lived experiences of distant others. We articulate linkages between these two discourses in an extended case study, finding that a cosmopolitan ethos of engagement in a rural context can improve (1) understanding among people ordinarily separated by spatialized social-ecological differences, (2) prospects for longer term environmental sustainability, and (3) the visionary potential of collaborative inquiry. Despite globalization of food systems and neoliberal shifts in fishery management, an annual fisheries forum facilitates coalitions that overcome dichotomies between technocratic and local knowledge, extending benefits to fishing communities, academia, and public policy. Iterative and loosely structured capacity building expands informally through affective processes of recognition and care, as decentralized leadership supports collective mobilization toward alternate futures

    Perception of Leitmotives in Richard Wagner's Der Ring des Nibelungen

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    The music of Richard Wagner tends to generate very diverse judgments indicative of the complex relationship between listeners and the sophisticated musical structures in Wagner’s music. This paper presents findings from two listening experiments using the music from Wagner’s Der Ring des Nibelungen that explores musical as well as individual listener parameters to better understand how listeners are able to hear leitmotives, a compositional device closely associated with Wagner’s music. Results confirm findings from a previous experiment showing that specific expertise with Wagner’s music can account for a greater portion of the variance in an individual’s ability to recognize and remember musical material compared to measures of generic musical training. Results also explore how acoustical distance of the leitmotives affects memory recognition using a chroma similarity measure. In addition, we show how characteristics of the compositional structure of the leitmotives contributes to their salience and memorability. A final model is then presented that accounts for the aforementioned individual differences factors, as well as parameters of musical surface and structure. Our results suggest that that future work in music perception may consider both individual differences variables beyond musical training, as well as symbolic features and audio commonly used in music information retrieval in order to build robust models of musical perception and cognition

    Niveles de Plomo en Sangre en México y su Implicación para la Carga Pediátrica de la Enfermedad

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    Antecedentes: Aunque con la gasolina libre de plomo ha habido éxito en la reducción de la exposición, en México la exposición al plomo continúa amenazando la salud de millones, la mayoría debido a la greta (óxido de plomo) que se utiliza en la alfarería donde el plomo se mezcla con la comida. Objetivos: Se condujo una revisión histórica extensiva y un análisis de datos de niveles de plomo en sangre en poblaciones mexicanas. Se usó una media geométricamente calculada para evaluar el efecto del plomo en la carga de la enfermedad de la población infantil. Métodos: Una búsqueda bibliográfica extensiva identificó 83 artículos publicados de 1978 al 2010 con datos de NPS en poblaciones mexicanas representando 150 puntos de datos de más de 50,000 participantes de los estudios. Se categorizaron los valores de estas publicaciones en varias agrupaciones. Enseguida se calcularon las incidencias de enfermedad y los AVAD resultantes de estos NPS, usando las hojas de cálculo de carga de enfermedad de la OMS para el retraso mental ligero. Resultados: Al revisar los estudios relevantes, las medias geométricas de niveles de plomo en sangre en México para áreas urbanas y rurales fueron de 8.85 μg/dL y 22.24 μg/dL respectivamente. A partir de la introducción de la gasolina libre de plomo, la media en áreas urbanas fue de 5.36 μg/dL y se espera que el promedio en áreas rurales sea mayor. El límite máximo de niveles de plomo en sangre para los CDCDC de EUA en niños menores de 6 años es de 5 μg/dL y el promedio actual en EUA es 1.2 μg/dL. Nuestros resultados indican que más del 15% de la población experimentará un decremento de más de 5 puntos en el coeficiente intelectual (CI)) a raíz de la exposición al plomo. El análisis también nos lleva a creer que el plomo es responsable de 820,000 AVAD por retraso mental ligero provocado por el plomo en niños de 0 a 4 años. Conclusión: En México el plomo continúa amenazando la salud de millones y sigue siendo una causa significativa de discapacidad. Se necesitan intervenciones adicionales en la reducción o manejo de óxido de plomo para proteger la salud pública

    The retinal hypercircuit: a repeating synaptic interactive motif underlying visual function

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    The vertebrate retina generates a stack of about a dozen different movies that represent the visual world as dynamic neural images or movies. The stack is embodied as separate strata that span the inner plexiform layer (IPL). At each stratum, ganglion cell dendrites reach up to read out inhibitory interactions between three different amacrine cell classes that shape bipolar-to-ganglion cell transmission. The nexus of these five cell classes represents a functional module, a retinal 'hypercircuit', that is repeated across the surface of each of the dozen strata that span the depth of the IPL. Individual differences in the characteristics of each cell class at each stratum lead to the unique processing characteristics of each neural image throughout the stack. This review shows how the interactions between the morphological and physiological characteristics of each cell class generate many of the known retinal visual functions including motion detection, directional selectivity, local edge detection, looming detection, object motion and looming detection
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