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Ali M De Francisco A Khan MM Chakraborty J Myaux J 《International journal of population geography : IJPG》1999,5(1):19-29
Substantial variation in contraceptive prevalence rates (CPRs) and fertility rates (FRs) between community health workers (CHWs) has been documented since the inception of the Matlab family planning program in rural Bangladesh. The coefficients of variation of these indicators for Matlab CHWs were 7% and 26%, respectively, in 1995. To identify the reasons for these performance variations, geographical information system (GIS) approaches were applied to longitudinal and cross-sectional data on 80 CHWs for the period 1980-95. Each observation in the data-set included catchment area-specific characteristics, measures of CHW efficiency in service delivery, and CHW-specific characteristics for one specific year. A one-unit increase in the average age of target women in the catchment area increases the CPR by 9.2%. The CPR increases by 0.2% for each 1% increase in women's literacy and decreases by 0.1% for each 1% increase in the number of Muslim households in the catchment area. An increase of 1 sq. km in the size of the catchment area reduces the CPR by 3%. CHW performance increases with age up to 45 years and then decreases. Similarly, a 1-year increase in the average age of target women reduces the FR by 2%. A 10% increase in the size of the catchment area reduces program performance by increasing the FR by 1.4%. A single geographic barrier to movement increases the FR by 1%. This analysis indicates that CHW performance can be improved significantly by defining catchment areas through use of GIS techniques. Without knowledge of the spatial distribution of population and the physical barriers to movement, allocating a fixed number of clients per CHW may not be the most efficient approach. 相似文献
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Ylitalo GM Myers M Stewart BS Yochem PK Braun R Kashinsky L Boyd D Antonelis GA Atkinson S Aguirre AA Krahn MM 《Marine pollution bulletin》2008,56(2):231-244
We analyzed blubber and blood samples for organochlorines (OCs) from 158 Hawaiian monk seals (Monachus schauinslandi) at four of their six primary breeding colonies in the Northwestern Hawaiian Islands. Levels of OCs in blubber were lower in adult females compared to juveniles or adult males, evidently owing to the transfer of these lipophilic compounds to pups by pregnant and lactating females. Concentrations of SigmaPCBs and p,p'-DDE in blubber generally increased with age until seals were sexually mature and then continued to increase with age in males after puberty. Average levels of PCBs and PCB toxic equivalents (TEQs) in blubber were significantly higher in adult male and juvenile seals at Midway Atoll than the same age class of seals at the other colonies. Unlike concentrations of OCs in blubber, circulating levels of OCs in blood did not vary consistently among age classes of seals or among breeding colonies. Though the concentrations of OCs measured in Hawaiian monk seals were generally equal to or lower than those reported for other pinniped species in the North Pacific Ocean, they were high enough in a few seals to potentially affect their health. 相似文献
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As competition for increasingly scarce ground water resources grows, many decision makers may come to rely upon rigorous multiobjective techniques to help identify appropriate and defensible policies, particularly when disparate stakeholder groups are involved. In this study, decision analysis was conducted on a public water supply wellfield to balance water supply needs with well vulnerability to contamination from a nearby ground water contaminant plume. With few alternative water sources, decision makers must balance the conflicting objectives of maximizing water supply volume from noncontaminated wells while minimizing their vulnerability to contamination from the plume. Artificial neural networks (ANNs) were developed with simulation data from a numerical ground water flow model developed for the study area. The ANN-derived state transition equations were embedded into a multiobjective optimization model, from which the Pareto frontier or trade-off curve between water supply and wellfield vulnerability was identified. Relative preference values and power factors were assigned to the three stakeholders, namely the company whose waste contaminated the aquifer, the community supplied by the wells, and the water utility company that owns and operates the wells. A compromise pumping policy that effectively balances the two conflicting objectives in accordance with the preferences of the three stakeholder groups was then identified using various distance-based methods. 相似文献
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da Silva DA Buzitis J Krahn MM Bícego MC Pires-Vanin AM 《Marine pollution bulletin》2006,52(2):175-183
This study reports the analysis of polycyclic aromatic compound (PAC) metabolites, as biomarkers of exposure to PACs in marine environment. PAC metabolites were measured in bile samples from 14 species of demersal fish caught in the São Sebastião Channel (SSC), SE Brazilian coastline. Naphthalene (NPH) equivalents, phenanthrene (PHN) equivalents, and benzo[a]pyrene (BaP) equivalents were quantified using a reverse-phase high-performance liquid chromatography coupled with fluorescence detection method. For all samples, the means (±standard deviation, n = 37) of concentrations obtained for NPH, PHN, and BaP equivalents were, respectively, 290,000 ± 200,000 ng/g, 18,000 ± 14,000 ng/g, and 970 ± 1900 ng/g. These results indicate recent exposure of these fish to PACs in their environment. In addition, two species (Cyclichthys spinosus and Prionotus nudigula) of fish were analyzed in order to investigate local sources of PAC contamination in the SSC and the influence of the petroleum terminal in fish caught in remote areas. The results showed that these fish species potentially migrate along the channel, especially P. nudigula. Correlations among groups of PAC metabolites indicate the same petrogenic source for NPH and PHN equivalents and a combustion source (e.g., automobile, ships) for BaP equivalents. The ratio BaP/PHN equivalents (0.05 ± 0.07, n = 37) confirms the predominance of petrogenic PACs for contamination by these chemicals in this region. 相似文献