Natural disturbance events influence the patterns and processes in many forest ecosystems. Ecosystem management of coniferous forests in western North America requires the recognition of the importance that natural disturbance regimes have in achieving sustainable resource production and maintaining biological diversity . Mountain pine beetle epidemics have played an historic role in the succession and structure of lodgepole pine forests in this region. Their effects on wildlife habitat and communities are undocumented, but are presumed to be substantial. I sought to quantify these effects in forty 1-ha stands of monotypic, even-aged, mature lodgepole pine forest in northern Utah approximately 3-8 years following an extensive epidemic. I selected 5 stands that were unaffected by the epidemic and 35 that had tree mortalities ranging from 14 to 95 %. Mean understory biomass in 50 1-m2 plots demonstrated an exponential increase from 4g m-2 in unaffected stands, 40 g m-2 in stands with moderate (51-75% dead) tree mortalities, and up to 110 g m-2 in severely (76-100 % dead) affected stands. Plant species diversity and heterogeneity were highest in stands with moderate tree mortality. Horizontal visual obscurity (from 0- 2.5 m high) was highest in stands with> 40% tree mortality. Canopy cover and volume decreased linearly and curvilinearly, respectively, with increasing tree mortality. Foliage height diversity was higher in stands with moderate tree mortality than in stands with high, low, or no mortality. Abundance and diversity of avian species were highest in stands with moderate tree mortality. Small and medium-sized mammal species were more abundant and diverse in stands with moderate and severe tree mortality than in stands with no or low (26-50 % dead) tree mortality, but the pattern is less clear than for avian species. Fecal pellet groups of large ungulates increased linearly with increasing tree mortality, but the pattern of occurrence of snowshoe hare fecal pellets to increasing tree mortality was less clear. Insect abundance and species diversity increased linearly with tree mortality. Canonical correspondence analysis of insect, avian, and mammalian communities revealed that understory vegetation biomass, diversity, and heterogeneity, as well as foliage height diversity, were the habitat factors that consistently explained the distribution of these species in stands affected by beetle-caused tree mortality.

The combat against viral diseases has been, and still is, a major challenge in the field of drug development. Viruses are intracellular parasites that use the host cell ma-chinery for their replication and release. Therefore it is difficult to target and destroy the viral particle without disturbing the essential functions of the host cell. This thesis describes studies towards antiviral agents targeting adenovirus type 37 (Ad37), which causes the severe ocular infection epidemic keratoconjunctivitis (EKC). Cell surface oligosaccharides serve as cellular receptors for many pathogens, including viruses and bacteria. For EKC-causing adenoviruses, cell surface oligo-saccharides with terminal sialic acid have recently been shown to be critical for their attachment to and infection of host cells. The work in this thesis support these re-sults and identifies the minimal binding epitope for viral recognition. As carbo-hydrate–protein interactions in general, the sialic acid–Ad37 interaction is very weak. Nature overcomes this problem and vastly improves the binding affinity by presenting the carbohydrates in a multivalent fashion. Adenoviruses interact with their cellular receptors via multiple fiber proteins, whereby it is likely that the ideal inhibitor of adenoviral infections should be multivalent. This thesis includes design and synthesis of multivalent sialic acid glycoconjugates that mimic the structure of the cellular receptor in order to inhibit adenoviral attachment to and infection of human corneal epithelial (HCE) cells. Synthetic routes to three different classes of sialic acid conjugates, i.e. derivatives of sialic acid, 3’-sialyllactose and N-acyl modified sialic acids, and their multivalent counterparts on human serum albumine (HSA) have been developed. Evaluation of these conjugates in cell binding and cell infectivity assays revealed that they are effective as inhibitors. Moreover the results verify the hypothesis of the multivalency effect and clearly shows that the power of inhibition is significantly increased with higher orders of valency. Potential inhibi-tors could easily be transferred to the eye using a salve or eye drops, and thereby they would escape the metabolic processes of the body, a major drawback of using carbohydrates as drugs. The results herein could therefore be useful in efforts to develop an antiviral drug for treatment of EKC.

This dissertation is about boys and fatness. In it I explore the central discourses that shape young men’s (13-15 years) experiences of their bodies, particularly in relation to body size, shape, and fatness. A central objective is to listen, hear, and take seriously the embodied health rationalities of young men as they negotiate the multiple and contesting discourses that confront them in their daily lives. I employ a feminist poststructural lens to account for the nuanced, alternative, and contextually specific ways young men think about and do health. Data collection was divided into three phases (non-participant observation, photo(focus) groups, and interviews) and was implemented at two Toronto area sites, including an exclusive private school and a publicly funded parks and recreation community centre. I demonstrate that there is not one way of experiencing fatness and masculinity, rather the young men’s constructions of fatness and health were fluid, shifting, contradictory and cross cut by other salient identity categories such as gender, race, ethnicity, social class, and age. Using Michel Foucault’s concept of governmentality, I show how obesity discourse provides a set of resources by which young men are able to construct themselves as autonomous, rational, neoliberal subjects, and how these subjectivities are differentially constituted depending on social and cultural positioning. I also reveal how differently raced and classed young men take up and embody normative ideals of the lean muscular male body through culturally appropriate masculine technologies of the self (i.e. sport and heterosexuality). The multiplicity of health and body discourses available to the young men gave rise to contested and ambivalent experiences and practices, such that dominant discourses were not always articulated in a straightforward and predictable manner, but were imbued with alternative and, in some cases, subversive meanings. To date, the social sciences have neglected to account for the relationship boys and men have with fatness discourses. By centering the analysis on the embodied experiences of diverse racialized and classed youth, this research demonstrates that weight and shape is more than a biomedical problem to be eradicated, but a discursively compelled embodiment that exists at the crossroads of the social, cultural, psychic, and biologic.

This thesis examines press framing of immigrant issues and epidemics in newspapers and periodicals, 1891 to 1893. During these years, immigration policies became more restrictive because of the Immigration Act of 1891, the opening of Ellis Island in 1892, the Chinese Exclusion Act of 1892, the New York City epidemics of 1892, the National Quarantine Act of 1893, and the nativist movement. Framing theory guided the following research questions: 1) How did articles in newspapers and periodicals frame immigrants and immigration issues in the context of epidemics from 1891 and 1893?; and 2) How did the press framing of immigrants and immigration issues in the context of epidemics from 1891 to 1893 reflect themes of nativism? This thesis contributes to the discourse about immigration because many Americans historically have learned about immigration issues from the press.

This dissertation is about boys and fatness. In it I explore the central discourses that shape young men’s (13-15 years) experiences of their bodies, particularly in relation to body size, shape, and fatness. A central objective is to listen, hear, and take seriously the embodied health rationalities of young men as they negotiate the multiple and contesting discourses that confront them in their daily lives. I employ a feminist poststructural lens to account for the nuanced, alternative, and contextually specific ways young men think about and do health. Data collection was divided into three phases (non-participant observation, photo(focus) groups, and interviews) and was implemented at two Toronto area sites, including an exclusive private school and a publicly funded parks and recreation community centre. I demonstrate that there is not one way of experiencing fatness and masculinity, rather the young men’s constructions of fatness and health were fluid, shifting, contradictory and cross cut by other salient identity categories such as gender, race, ethnicity, social class, and age. Using Michel Foucault’s concept of governmentality, I show how obesity discourse provides a set of resources by which young men are able to construct themselves as autonomous, rational, neoliberal subjects, and how these subjectivities are differentially constituted depending on social and cultural positioning. I also reveal how differently raced and classed young men take up and embody normative ideals of the lean muscular male body through culturally appropriate masculine technologies of the self (i.e. sport and heterosexuality). The multiplicity of health and body discourses available to the young men gave rise to contested and ambivalent experiences and practices, such that dominant discourses were not always articulated in a straightforward and predictable manner, but were imbued with alternative and, in some cases, subversive meanings. To date, the social sciences have neglected to account for the relationship boys and men have with fatness discourses. By centering the analysis on the embodied experiences of diverse racialized and classed youth, this research demonstrates that weight and shape is more than a biomedical problem to be eradicated, but a discursively compelled embodiment that exists at the crossroads of the social, cultural, psychic, and biologic.

Recent World Animal Health Organization (OIE) reports on Avian Influenza (AI) outbreaks in Asia, Europe and Canada suggest that there is a nonzero probability that an outbreak may occur anywhere in the world, including the US. To help evaluate possible policy in the face of such an event, this dissertation does an economic evaluation of the implications of using two mitigation strategies: one corresponding to the currently response strategy; and the other an OIE recommended one utilizing vaccination. To do this, the dissertation develops and uses an integrated economic-epidemic model. In this effort, I first estimate the cost of an AI outbreak under a deterministic disease spread assumption where a new vaccination strategy and the current strategy are compared. Subsequently, I introduce risk in the model and construct 95 percent confidence intervals for the outbreak costs, and I rank the outcomes of the alternative strategies using stochastic dominance criteria. In addition, during both phases, I develop and estimate the breakeven probability for an event where ex-ante fixed costs of vaccine stockpiling are justified by the reduction in disease event damages. Results under deterministic disease spread assumption suggest that the vaccination strategy lowers the cost of outbreaks as opposed to the current strategy. This happens because vaccination reduces the number of culled and quarantined flocks. The study is conducted in three locations, yielding the finding that the costs of an outbreak vary depending on the densities of poultry flocks. I also find that when consumer demand shifts due to the outbreak, the costs are much larger. Finally, I find that ex-ante vaccine stockpiling is justified for all the sub-regions if the probability of outbreak exceeds 0.07. The stochastic disease spread assumption results also show that the vaccination strategy dominates in first degree stochastic dominance sense. Consistent with stochastic dominance results, the 95 percent confidence intervals have narrower ranges under the vaccination strategy than without it. Finally, the distribution of the breakeven probability for vaccine stocking has a mode of 0.07 and that the probability is accurate with 82 percent likelihood. However, the threshold varies with the disease transmission parameters and could reach up to 0.32.

Foreign animal disease can cause serious damage to the United States (US) agricultural sector and foot-and-mouth disease (FMD), in particular, poses a serious threat. FMD causes death and reduced fecundity in infected animals, as well as significant economic consequences. FMD damages can likely be reduced through implementing pre-planned response strategies. Empirical studies have evaluated the economic consequences of alternative strategies, but typically employ simplified models. This dissertation seeks to improve US preparedness for avoiding and/or responding to an animal disease outbreak by addressing three issues related to strategy assessment in the context of FMD: integrated multi region economic and epidemic evaluation, inclusion of risk, and information uncertainty. An integrated economic/epidemic evaluation is done to examine the impact of various control strategies. This is done by combining a stochastic, spatial FMD simulation model with a national level, regionally disaggregated agricultural sector mathematical programming economic model. In the analysis, strategies are examined in the context of California's dairy industry. Alternative vaccination, disease detection and movement restriction strategies are considered as are trade restrictions. The results reported include epidemic impacts, national economic impacts, prices, regional producer impacts, and disease control costs under the alternative strategies. Results suggest that, including trade restrictions, the median national loss from the disease outbreak is as much as $17 billion when feed can enter the movement restriction zone. Early detection reduces the median loss and the standard deviation of losses. Vaccination does not reduce the median disease loss, but does have a smaller standard deviation of loss which would indicate it is a risk reducing strategy. Risk in foreign animal disease outbreaks is present from several sources; however, studies comparing alternative control strategies assume risk neutrality. In reality, there will be a desire to minimize the national loss as well as minimize the chance of an extreme outcome from the disease (i.e. risk aversion). We perform analysis on FMD control strategies using breakeven risk aversion coefficients in the context of an outbreak in the Texas High Plains. Results suggest that vaccination while not reducing average losses is a risk reducing strategy. Another issue related to risk and uncertainty is the response of consumers and domestic markets to the presence of FMD. Using a highly publicized possible FMD outbreak in Kansas that did not turn out to be true, we examine the role of information uncertainty in futures market response. Results suggest that livestock futures markets respond to adverse information even when that information is untrue. Furthermore, the existence of herding behavior and potential for momentum trading exaggerate the impact of information uncertainty related to animal disease.

Master of Science / Department of Diagnostic Medicine/Pathobiology / Weiping Zhang / Porcine epidemic diarrhea virus (PEDV) causes acute diarrhea to pigs at all ages, resulting in high mortality rate of 80-100% in piglets less than one week old. Within one year after the outbreak in April 2013, PEDV has rapidly spread in the US and causes the loss of over 10% of the US pig population. Monoclonal antibody (mAb) is a key reagent for rapid diagnosis of PEDV infection. In this study, we produced a panel of mAbs against nonstructural protein 8 (nsp8), spike(S) protein, and nucleocapsid (N) protein of PEDV. Four mAbs were selected, which can be used in various diagnostic assays, including indirect immunofluorescence assay (IFA), enzyme-linked immunoabsorbent assay (ELISA), Western Blot, immunoprecipitation (IP), immunohistochemistry (IHC) test and fluorescence in situ hybridization (FISH). The mAb 51-79 recognizes amino acid (aa) 33-60 of nsp8, mAb 70-100 recognizes aa1371-1377 of S2 protein, and mAb 66-155 recognizes aa 241-360 of N protein, while mAb 13-519 is conformational. Using the mAb70-100, the immunoprecipitated S2 fragment was examined by protein N-terminal sequencing, and cleavage sites between S1 and S2 was identified. In addition, this panel of mAbs was further applied to determine the infection site of PEDV in the pig intestine. IHC test result showed that PEDV mainly located at the mid jejunum, distal jejunum and ileum. Results from this study demonstrated that this panel of mAbs provides a useful tool for PEDV diagnostics and pathogenesis studies.

1962. Tanganyika, East Africa. In a rural boarding school on the shore of Lake Victoria, dozens of adolescent girls began to laugh and cry uncontrollably. After trying to stem these mysterious breakouts for a month and a half, school officials gave up and sent everyone home. As the girls fanned out to their homes across the region, their behaviors spread too. Over 1000 people were affected. Families and governments enlisted all kinds of experts to give them a clue about what was going on. Eventually, an official diagnosis: mass hysteria. About two years after it began, the epidemic petered out. Nobody died. Everybody recovered. / History of Science

Individual-level models (ILMs) are models that can use the spatial-temporal nature of disease data to capture the disease dynamics. Parameter estimation is usually done via Markov chain Monte Carlo (MCMC) methods, but correlation between model parameters negatively affects MCMC mixing. Introducing a normalization constant to alleviate the correlation results in MCMC convergence over fewer iterations, however this negatively effects computation time. It is important that model fitting is done as efficiently as possible. An upper-truncated distance kernel is introduced to quicken the computation of the likelihood, but this causes a loss in goodness-of-fit. The normalization constant and upper-truncated distance kernel are evaluated as components in various ILMs via a simulation study. The normalization constant is seen not to be worthwhile, as the effect of increased computation time is not outweighed by the reduced correlation. The upper-truncated distance kernel reduces computation time but worsens model fit as the truncation distance decreases. / Studies have been funded by OMAFRA & NSERC, with computing equipment provided by CSI.