Geographic diffusion of multiple-drug-resistant HIV--论文代写范文精选

有效控制病原体需要回归传统的公共卫生策略，改善生活和工作条件。这类干预措施提供了一个战略,去谐的协同因素产生一个连贯的,社会和地理扩散。社区艾滋病是一种边缘化的形式。下面的paper代写范文将进行详述。

Abstract 
Public policy and economic practice, both quintessential expressions of institutional cognition, create an opportunity structure constituting a tunable, highly patterned, ‘nonwhite noise’ in a generalized epidemiological stochastic resonance which can efficiently amplify unhealthy conditions within marginalized populations to evoke infectious disease outbreaks. This is particularly true for infections carried by socially-generated ‘risk behaviors’. A number of local epidemics originating in such keystone communities may subsequently undergo a structure-driven phase transition to become a coherent pandemic, a spreading plague which can entrain more affluent populations into the disease ecology of marginalization. Here we apply this perspective, which is formally homologous to recent theoretical developments in cognitive psychology, to the forthcoming social and geographic diffusion of multiple drug resistant (MDR) HIV from current AIDS epicenters to the rest of the United States. HIV is an evolution machine, easily able to mutate around the selection pressures generated by both microbicides and vaccines. 

Effective control of the pathogen will require a return to traditional public health strategies aimed squarely at improving living and working conditions. Such interventions provide a strategic, ecosystem-wide, detuning of the synergistic factors generating a coherent, socially and geographically diffusing, behaviorally-transmitted infection. Broad, traditionally progressive, public policy is needed to significantly improve the embedding opportunity structure and spatiotemporal stability of communities in which AIDS is a primary index of marginalization. MDR-HIV is poised to spread across the US in much the same manner as the early, pre-HAART, stages of the pandemic. Absent significant regime change, the Katrina disaster affecting New Orleans provides a sentinel case history for the likely outcome. KEY WORDS Apartheid, information theory, phase transition, renormalization, recurrent epidemic, social inequality, stochastic resonance.

INTRODUCTION 
Affluent subpopulations in the US have benefited greatly from the introduction of highly active antiretroviral therapy (HAART) against HIV: from 1995 to 1997, for example, HIV/AIDS deaths declined 63 % in New York City, primarily among middle-class, and highly organized, Gay males (Chiasson et al., 1999). Declines in AIDS deaths have otherwise been quite heterogeneous, depending critically on both the economic resources and community stability of affected populations (e.g. R.G. Wallace, 2003). At present, AIDS deaths in the US are, largely, another marker of longstanding patterns of racism and socioeconomic inequity (e.g. Wallace and McCarthy, 2006). 

Those who have economic resources, or reside in stable communities not subject to various forms of ‘redlining’, have effective access to HAART, others do not. HIV is, however, an evolution machine (e.g. Rambaut et al., 2004) which, at the individual level, almost always develops multiple drug resistance, resulting in overt AIDS and subsequent premature fatality. Such response to chemical pesticides, as has been the case with myriad other biological pests, is now becoming manifest at the population level. By 2001 in the US some 50 % of patients receiving antiretroviral therapy were infected with viruses that express resistance to at least one of the available retroviral drugs, and transmission of drugresistant strains is a growing concern (Clavel and Hance, 2004; Grant et al., 2002). MDR-HIV is, in fact, rapidly becoming the norm, and the virus may even develop a far more virulent life history strategy in response to the evolutionary challenges presented by HAART, its successor microbicide strategies, or planned vaccines (R.G. Wallace, 2004), a circumstance which may have already been observed (e.g. Simon et al., 2003).

DISCUSSION AND CONCLUSIONS 
Infectious diseases do not, in general, simply constitute a dye marker for urban sociogeography, although the overall pattern of social and geographic spread is certainly constrained by, and must be consistent with, the underlying sociogeography. Consideration of the prehistory probability distribution and the distribution of fluctuational paths suggests the possibility of understanding the phenomenon in terms of a generalized stochastic resonance having a dual ergodic information source, a kind of language. 

Paths of signal – community structure – convoluted with noise – the embedding opportunity structure – which are not consistent with the grammar and syntax of that language cannot trigger simple epidemic outbreaks, or, taking the nested Martingale perspective, turn a declining infection into a rising one. Conversely, for a given fixed signal – community structure – there will be an optimal noise – opportunity structure – whose convolution, analogous to coding, permits the system to approach a channel capacity measure arbitrarily closely. That is, certain patterns of constricted opportunity will most efficiently trigger repeated outbreaks of infectious epidemic disease in marginalized communities, or turn a falling endemic infection into a growing one. 

Further development shows that spatially (or sociospatially) distributed systems undergoing such generalized stochastic resonance can be subject to phase transition at critical values of driving parameters, which may encompass signal and non-linear amplifier as well as noise. These transitions should follow ‘universal’ power laws, depending on the appropriate renormalization symmetry, which is itself related to the underlying sociogeographic architecture. Conversely, this analysis suggests isolated, incoherent spatiotemporal infectious epidemic resonators – individual neighborhoods, counties, or metropolitan regions – may suddenly coalesce into a single powerful and coherent amplifier, a spatially contagious or hierarchically spreading pandemic, under the influence of particular constrained opportunity structures. 

This result has formal similarities to recent developments in cognitive theory, and suggests that diseases of marginalization, and their control, are very much creatures of institutional cognition, related to overt decisions regarding allocation of resources. The analysis by Wallace et al. (1997) on the regional conformations of the early stages of AIDS in eight US metropolitan areas seems to provide a case history. As discussed, the two principal US AIDS epicenters of San Francisco and New York City showed markedly different forms of regionalization. New York had a coherent disease pattern across the entire metropolitan area, strongly dominated by the commuting center of Manhattan, while the San Francisco metro area, at least for the period studied, remained a patchwork of several individual outbreaks. 

As described earlier, the two cities took significantly different approaches to reinforcement of the system of US Apartheid following the challenges of the Southern-based Civil Rights Movement. San Francisco made the city center attractive to White middle class residents, while New York drove some 1.3 million non-Hispanic Whites and other middle class residents from the city to the suburbs, tightening the weak ties linking counties of the metro region beyond threshold, and creating a unified disease ecosystem. The synergistic unification of community, policy, and epidemic infectious disease into a language of power relations defined by the generalized stochastic resonance of emerging infectious disease suggests that public health interventions against plague must be similarly synergistic and hierarchical to bring the system below coherent threshold.(paper代写)


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