Geography of biomedical publications.
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This paper focuses on the issue of how a research project can shift from a positivist to a nonpositivist framework. Specific attention is given to changes in research methods and philosophical paradigm that emerged while conducting a study on the replacement of immigrant physicians in rural America. In its original conceptualization, the study was expected to yield a simple, right answer. Specifically, one or more types of health professionals (e.g., nurse practitioners, National Health Service Corps physicians) would be identified as expected replacements in the event of a cutback on immigrant physicians. However, as the research progressed, the quest for a simple, right answer became less realistic. The theoretical framework, methods, and research question changed, thereby allowing for greater complexity and ambiguity than anticipated at the outset of the study. What had been a positivist, statistical study was now a nonpositivist, qualitative study, and the research question shifted to include individual perspectives. An overview of such transitions leads to a discussion of the importance of context and ambiguity in research.
During the 1990s, the number of new AIDS cases in New York City, USA, declined precipitously. The declines, beginning before highly active antiretroviral therapy (HAART) was introduced, were geographically heterogeneous across two New York City boroughs analyzed. From 1993 to 1998, zip codes in Lower Manhattan, with large white and affluent populations, had declines as much as 55% more than the rest of Manhattan. Bronx zip codes underwent still lesser declines. Declines also differed within zip codes among subpopulations. White zip code populations tended to have greater declines than Latino populations, which in turn tended to have greater declines than black populations. According to bivariate and stepwise regressions, an array of socioeconomic and community stress variables acted in combination on the decline in New York AIDS. Manhattan's declines in total AIDS incidence were primarily defined by changes in AIDS incidence for whites and for men who have sex with men, racial segregation, and the proportions of households in upper income classes and under rent stress. Bronx declines in total AIDS are principally explained by a broader range of income classes, and social instability as marked by housing overcrowding and cirrhosis and drug mortalities. Whatever the combination of proximate causes for the decline in AIDS incidence in 1990s New York (educational campaigns, HAART, demographic stochasticity), the decline was shaped by the city's socioeconomic structure and political and ecological history. That structure and history generates the geographically defined aggregates of behaviors that promote or impede AIDS decline. Such spatial heterogeneity may provide for HIV refugia, areas where the virus can weather the epidemic's contraction, a troubling possibility with the accelerating microbicidal failures of combination therapies.
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Emerging infectious diseases are the focus of increased attention and even alarm in the scholarly and popular literature. The emergence of new diseases and the resurgence of older and previously recognized infectious diseases both in developing and developed country poses challenges for understanding the ecological web of causation, including social, economic, environmental and biological components. This paper is a synthesis of the major characteristics of emerging diseases, in an interdisciplinary context. Political ecology is one framework for analysis that is promising in developing a modified ecology of disease.
This paper focuses on the question of sampling (or selection of cases) in qualitative research. Although the literature includes some very useful discussions of qualitative sampling strategies, the question of sampling often seems to receive less attention in methodological discussion than questions of how data is collected or is analysed. Decisions about sampling are likely to be important in many qualitative studies (although it may not be an issue in some research). There are varying accounts of the principles applicable to sampling or case selection. Those who espouse 'theoretical sampling', based on a 'grounded theory' approach, are in some ways opposed to those who promote forms of 'purposive sampling' suitable for research informed by an existing body of social theory. Diversity also results from the many different methods for drawing purposive samples which are applicable to qualitative research. We explore the value of a framework suggested by Miles and Huberman [Miles, M., Huberman,, A., 1994. Qualitative Data Analysis, Sage, London.], to evaluate the sampling strategies employed in three examples of research by the authors. Our examples comprise three studies which respectively involve selection of: 'healing places'; rural places which incorporated national anti-malarial policies; young male interviewees, identified as either chronically ill or disabled. The examples are used to show how in these three studies the (sometimes conflicting) requirements of the different criteria were resolved, as well as the potential and constraints placed on the research by the selection decisions which were made. We also consider how far the criteria Miles and Huberman suggest seem helpful for planning 'sample' selection in qualitative research.
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For a variety of purposes it is increasingly necessary to establish the health needs of local populations. Following a critique of existing proxies of need, this paper presents and evaluates an alternative which draws upon epidemiological evidence concerning the age, sex and social class distribution of morbidity in order to estimate the prevalence of specific conditions in designated populations. By way of demonstrating the insights to be gained through the use of these indicative prevalence rates, the paper considers the treatment of ischaemic heart disease in a sample of 539 practices and presents evidence regarding the significance of deprivation and rurality in determining health service use relative to needs.
After decades of sustained child mortality reductions, infant and early childhood mortality levels in Africa remain high. This can partly be ascribed to the concentration of child mortality within particular families, communities or geographic localities. Strong mortality clustering is indicative of marked social inequality and of an unequal distribution of health and health-related resources and infrastructures. It also signifies a concentration of nutritional and sanitary behaviors harmful to the good health and longevity of children. Finally, it likely points to the existence of particular genetic problems in certain families, or environmental problems within specific communities. Using nationally representative family level data from all sub-regions of Africa, two important findings emerge from this study. First, levels of mortality have generally declined in all countries over time, and as mortality decreases, mortality clustering tends to follow the same trend. Second, bio-demographic covariates have a more important effect on familial mortality clustering risks than socio-economic ones.
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Biodiversity theory proposes two types of hypotheses to account for the species composition of a given community. The first encompasses geographic and historical factors. For example, local species richness is thought to be affected by area, proximity to large landmasses, dispersal mechanisms, and climatic history, collectively known as biogeography. The second type, termed niche occupancy rules, deals with the intrinsic properties of the species as they affect their interaction with the habitat and with other members of the community. The yeast-insect-morning glory ecosystem is a good model to explore biodiversity theory in ascomycetous yeasts. Here we focus on beetles that breed or feed in morning glories and a group of ascomycetous yeasts that are associated exclusively with them. Specifically, we analyse the community found in the vicinity of Kīpuka Puaulu, a small patch of disturbed but mature forest situated amidst lava flows on the island of Hawai'i. Major members of the yeast community include Metschnikowia hawaiiensis, Metschnikowia lochheadii, and the related asexual species Candida ipomoeae and Candida kipukae. These species are nearly indistinguishable from one another in terms of nutritional requirements and abilities, although their phylogenetic range is enormous. Their distribution, both global and local, is far from random. As Kīpuka Puaulu is an island within an island, the principles of island biogeography may be invoked to explain some aspects of its yeast species composition. M. lochheadii, C. ipomoeae, and the rare species Candida hawaiiana are recent introductions from the American continent and therefore exotic, whereas M. hawaiiensis and C. kipukae might be regarded as endemic, as they are yet to be isolated elsewhere. Vectoring by certain nitidulid beetles explains the long-range dispersal of these species. However, niche occupancy rules may account in part for the local spatial distribution of the yeasts within the island of Hawai'i and within the kīpuka itself. We have identified the maximum growth temperature as a potentially critical property of the fundamental niche of these yeasts.