Thesis (M.A.)--Georgia State University, 2008. / Title from file title page. Leonary Ray Teel, committee chair; Jeffrey Bennett, Holley Wilkin, committee members. Description based on contents viewed Sept. 22, 2009. Includes bibliographical references (p. 99-112).

Thesis (Ph.D.)--Memorial University of Newfoundland, 2004. / Bibliography: leaves 141-151.

Thesis (M.A.) University of Missouri-Columbia, 2004. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 29, 2006) Vita. Includes bibliographical references.

This thesis is concerned with quantifying the dynamical role of stochasticity in models of recurrent epidemics. Although the simulation of stochastic models can accurately capture the qualitative epidemic patterns of childhood diseases, there is still considerable discussion concerning the basic mechanisms generating these patterns. The novel aspect of this thesis is the use of analytic methods to quantify the results from simulations. All the models are formulated as continuous time Markov processes, the temporal evolutions of which is described by a master equation. This is expanded in the inverse system size, which decomposes the full stochastic dynamics into a macroscopic part, described by deterministic equations, plus a stochastic fluctuating part. The first part examines the inclusion of non-exponential latent and infectious periods into the the standard susceptible-infectious-recovered model. The method of stages is used to formulate the problem as a Markov process and thus derive a power spectrum for the stochastic oscillations. This model is used to understand the dynamics of whooping cough, which we show to be the mixture of an annual limit cycle plus resonant stochastic oscillations. This limit cycle is generated by the time-dependent external forcing, but we show that the spectrum is close to that predicted by the unforced model. It is demonstrated that adding distributed infectious periods only changes the frequency and amplitude of the stochastic oscillations---the basic mechanisms remain the same. In the final part of this thesis, the effect of seasonal forcing is studied with an analysis of the full time-dependent master equation. The comprehensive nature of this approach allows us to give a coherent picture of the dynamics which unifies past work, but which also provides a systematic method for predicting the periods of oscillations seen in measles epidemics. In the pre-vaccination regime the dynamics are dominated by a period doubling bifurcation, which leads to large biennial oscillations in the deterministic dynamics. Vaccination is shown to move the system away from the biennial limit cycle and into a region where there is an annual limit cycle and stochastic oscillations, similar to whooping cough. Finite size effects are investigated and found to be of considerable importance for measles dynamics, especially in the biennial regime.

This dissertation approaches key questions in the study of colonial urban modernity through methods in the history of medicine and sciences. Through a comparative focus on the colonial cities of Bombay and Calcutta, I explore the new found interests of colonial urban planners, public health experts, and Indian social elites in the “unclaimed bodies” of the poor, which were considered both diseased and disposable, and attendant concerns with the scientific management of subaltern death. By exploring the converging logics yet the divergent outcomes of colonial state and native elite efforts to manage the death of the urban poor and indigent as an urban problem that required scientific solutions such as the gas crematorium or relegating mass burials for unclaimed bodies to the suburbs, this study in comparative urbanism demonstrates how the imperatives of colonial public health and political economy followed by a heightened period of native critique between the two world wars reconfigured global ideas of health and technologies. From the mid-nineteenth century, epidemics and famines had provided the occasion for British and Indian social elites to reconstitute social power and remake boundaries of caste and community in the context of urban migration and industrial labor. While famines happened in Western India, an emergent preoccupation with tropical diseases in Eastern India had reconfigured the meaning and the social experience of death for the urban poor. Working class bodies thus became the locus of the entangled knowledge-making of health, technology, and religion in regionally specific ways. In particular, modern technologies such as the gas and electric crematorium enabled the spatial reorganization of labor, caste, and community in the service of a colonial political economy: modern technologies for the efficient and hygienic disposal of the dead bodies of the indigent and impoverished were thus also solutions for managing the lives of the working castes and classes. The scientific management of subaltern death was not just the preoccupation of anatomists, doctors, and public health engineers but as well, of the British Parliament, international health organizations, Indian and British members of municipalities, missionaries, religious charity leaders, communal organizations, anti-caste leaders, and subaltern mortuary workers. Simultaneously, anti-colonial and subaltern politics transformed the effects of scientific knowledge and infrastructure in both Bombay and Calcutta, albeit differently in response to framing antagonisms of caste, capital, and community. Thus, despite the normalizing and homogenizing impetus of colonialism, health policies and attendant technologies reacted to and reflected the impact of local configurations of power and urban space. Putting the history and anthropology of death into conversation with the global history of medicine, science, and technology in the context of colonial and postcolonial South Asia allows us to understand how global technologies under imperialism engaged with local social meanings to bring about epistemic shifts in perceptions and practices of the body, while also altering spatial and social relations. The subcontinental history of the crematorium thus reflects the ongoing impact of discourses and infrastructures of public health and hygiene in redefining bodies marked by social distinctions of caste, class and religion in the colonial metropole through acts of spatial politics. The introduction of the crematorium in colonial India reproduced extant practices of social hierarchy and spatial segregation but it also became an enabling infrastructure through which anti-caste activists, Marxists and Socialists imagined scientific modernity and a future without segregation.

No description available.

The main goal of my studies has been to search for the optimal control strategy of controlling epidemics when taking into account both economical and social costs of the disease. Three control scenarios emerge with treating the whole population (global strategy, GS), treating a small number of individuals in a well-defined neighbourhood of a detected case (local strategy, LS) and allowing the disease to spread unchecked (null strategy, NS). The choice of the optimal strategy is governed mainly by a relative cost of palliative and preventive treatments. Although the properties of the pathogen might not be known in advance for emerging diseases, the prediction of the optimal strategy can be made based on economic analysis only. The details of the local strategy and in particular the size of the optimal treatment neighbourhood weakly depends on disease infectivity but strongly depends on other epidemiological factors (rate of occurring the symptoms, spontaneously recovery). The required extent of prevention is proportional to the size of the infection neighbourhood, but this relationship depends on time till detection and time till treatment in a non-nonlinear (power) law. The spontaneous recovery also affects the choice of the control strategy. I have extended my results to two contrasting and yet complementary models, in which individuals that have been through the disease can either be treated or not. Whether the removed individuals (i.e., those who have been through the disease but then spontaneously recover or die) are part of the treatment plan depends on the type of the disease agent. The key factor in choosing the right model is whether it is possible - and desirable - to distinguish such individuals from those who are susceptible. If the removed class is identified with dead individuals, the distinction is very clear. However, if the removal means recovery and immunity, it might not be possible to identify those who are immune. The models are similar in their epidemiological part, but differ in how the removed/recovered individuals are treated. The differences in models affect choice of the strategy only for very cheap treatment and slow spreading disease. However for the combinations of parameters that are important from the epidemiological perspective (high infectiousness and expensive treatment) the models give similar results. Moreover, even where the choice of the strategy is different, the total cost spent on controlling the epidemic is very similar for both models. Although regular and small-world networks capture some aspects of the structure of real networks of contacts between people, animals or plants, they do not include the effect of clustering noted in many real-life applications. The use of random clustered networks in epidemiological modelling takes an impor- tant step towards application of the modelling framework to realistic systems. Network topology and in particular clustering also affects the applicability of the control strategy.

No description available.

Social networks play an important role in disseminating a piece of information in a population. Companies advertising a newly launched product, movie promotion, political campaigns, social awareness campaigns by governments, charity campaigns by NGOs and crowd funding campaigns by entrepreneurs are a few examples where an entity is interested in disseminating a piece of information in a target population, possibly under resource constraints. In this thesis we model information diffusion in a population using various epidemic models and study optimal campaigning strategies to maximize the reach of information. In the different problems considered in this thesis, information epidemics are modeled as the Susceptible-Infected, Susceptible-Infected-Susceptible, Susceptible-Infected-Recovered and Maki Thompson epidemic processes; however, we modify the models to incorporate the intervention made by the campaigner to enhance information propagation. Direct recruitment of individuals as spreaders and providing word-of-mouth incentives to the spreaders are considered as two intervention strategies (controls) to enhance the speed of information propagation. These controls can be implemented by placing advertisements in the mass media, announcing referral/cash back rewards for introducing friends to a product or service being advertised etc. In the different problems considered in this thesis, social contacts are modeled with varying levels of complexity---population is homogeneously mixed or follows heterogeneous mixing. The solutions to the problems which consider homogeneous mixing of individuals identify the most important periods in the campaign duration which should be allocated more resources to maximize the reach of the message, depending on the system parameters of the epidemic model (e.g., epidemics with high and low virulence). When a heterogeneous model is considered, apart from this, the solution identifies the important classes of individuals which should be allocated more resources depending upon the network considered (e.g. Erdos-Renyi, scale-free) and model parameters. These classes may be carved out based on various centrality measures in the network. If multiple strategies are available for campaigning, the solution also identifies the relative importance of the strategies depending on the network type. We study variants of the optimal campaigning problem where we optimize different objective functions. For some of the formulated problems, we discuss the existence and uniqueness of the solution. Sometimes our formulations call for novel techniques to prove the existence of a solution.

This thesis examines the development and use of environmental health indicators for epidemiology, risk assessment and policy applications from a geographical perspective. Although indicators have traditionally been used to examine temporal trends, the development of environmental health indicators (EHIs) may enable comparisons to be made between areas with contrasting environmental health conditions, support efforts to highlight ‘hot spots’ and facilitate the analysis of spatial patterns in environmental health conditions and health risk. The use of environmental health indicators is relatively new and little research has been conducted in this area. In the light of this, this thesis examines EHIs in the context of contemporary developments in environmental indicators, health-related and quality of life indicators, and indicators of sustainable development. Essential characteristics and requirements for EHIs are identified and the main areas of application are discussed. In the second part of the thesis, the development and use of Effis for evaluating exposure to traffic-related air pollution is examined, using GIS techniques. Potential indicators of exposure are identified and these are applied at a range of spatial scales, along with a number of additional measures. The results of this exercise show that although exposure to traffic-related air pollution is both difficult and costly to evaluate, proxy measures may be used. Pollutant concentrations, for example are frequently used to assess exposure, yet the lack of suitable data may also frequently preclude their use. Whilst other, cruder measures may be used, the relationship between these indicators, measured concentration and exposure is often uncertain. Consequently, EHIs for exposure to traffic-related air pollution may not provide a reliable indication of exposure and health risk. Their use in this area should therefore be undertaken with great caution and attempts made to validate specific measures prior to their use. At the same time, however, coarser ‘upstream’ indicators may provide relevant information in a policy context. For use in highlighting areas of concern, raising awareness about environmental health issues and encouraging policies which aim to improve environmental health conditions, ease of data collection and relation to policy may be more important than relation to specific health effects