Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Epidemiology and Fungicide Sensitivity of Grape Late Season Bunch Rots in the Mid-Atlantic(2022) Cosseboom, Scott David; Hu, Mengjun; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This project aims to improve the management of late season bunch rots of grape (LSBR) whichcan be caused by a wide range of fungal pathogens. LSBR collectively have been an increasing issue in Mid-Atlantic vineyards, severely affecting grape yield and quality. Despite intensive fungicide spray programs and cultural practices, severe LSBR epidemics threaten the budding Mid-Atlantic wine industry. The basic plant pathological variables of host, pathogen, and environment were investigated to improve knowledge of the diseases involved, and therefore improve management strategies. The most common causal agents of LSBR in the Mid-Atlantic were found to be Botrytis cinerea and Colletotrichum spp. and the species identity of less common fungi was also investigated. The next most prevalent fungi associated with LSBR, Alternaria alternata, Aspergillus uvarum, and Neopestalotiopsis rosae were evaluated for pathogenicity in field experiments through the artificial inoculation of grape clusters. Second, the sensitivity of A. uvarum, B. cinerea, and N. rosae to commonly used chemical classes of fungicides was tested. Lastly, the optimal infection conditions and timing for Colletotrichum spp. were evaluated in laboratory, field, and greenhouse experiments, resulting in a quantitative inoculum tracking technique and a disease prediction model. These experiments were focused on solving practical and important disease management issues experienced by local grape growers, while conducting novel research that was applicable to the broader science community. Beyond the increased knowledge of the etiology and epidemiology of LSBR, the conclusions of this research could lead to reformed LSBR management strategies with the elimination of unnecessary and ineffective fungicide applications, increased accuracy and timing of management efforts, and increased marketable grape yield.Item The Distribution of Care: A Modular Facility for the Treatment of Disease-Stricken Communities in Africa(2020) Winters, Kelsey; Gabrielli, Julie; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Africa experiences a disproportionate amount of the global disease burden, and existing health care centers struggle to meet everyday patient needs. During a disease epidemic, this inability to accommodate communities is exacerbated by a lack of resources to diagnose and treat infectious disease as well as a physical separation from the location of outbreaks. This thesis investigates how patients of disease outbreaks in Africa can be better accommodated through the exploration of a modular health facility capable of treating communities no matter when and where an outbreak occurs. Outbreaks unexpectedly affect vulnerable populations, and immediate action is crucial to contain the disease. The current Ebola outbreak in the Democratic Republic of Congo is utilized as a case study in this thesis, considering its relevance as an ongoing epidemic. Due to the abrupt and destructive nature of disease, a modular and flexible health facility is needed to handle any outbreak in any location.Item MORTALITY AND REOVIRUS INFECTION IN SOFT-SHELL BLUE CRAB (CALLINECTES SAPIDUS) AQUACULTURE(2019) Spitznagel, Matthew Isaac; Schott, Eric J; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Soft-shell blue crab production the United States is an undervalued aquaculture practice experiencing high crab mortality rates from a series of stressors, including disease. The impact of one disease, the reovirus CsRV1, remains unquantified in major soft-shell crab production regions, despite the virus’ known ubiquity and lethality. My research examined the mortality and CsRV1 infection rates of pre- and post-production crabs in Maryland, Virginia, and Louisiana soft-shell crab production facilities in 2016-2017, attempting to link these rates to water quality and aquaculture practice variables. I found that recirculating aquaculture systems lost half the proportion of crabs (16%) that flow-through systems did (33%). CsRV1 infection was the primary predictor of crab death in Chesapeake aquaculture, presenting in 75% of dead crabs compared to 22% of dead crabs in Louisiana aquaculture. Multi-state data suggests crab losses worth over $2 million are attributable to CsRV1, indicating a need for aquaculture effluent and discard control.Item Infectious Disease in Philadelphia, 1690-1807: An Ecological Perspective(2006-05-15) Anroman, Gilda Marie; Sies, Mary Corbin; American Studies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the multiple factors that influenced the pattern and distribution of infectious disease in Philadelphia between the years 1690 and 1807, and explores the possible reasons for the astonishingly high level of death from disease throughout the city at this time. What emerges from this study is a complex picture of a city undergoing rapid cultural and epidemiological changes. Large-scale immigration supplied a susceptible population group, as international trade, densely packed streets, unsanitary living conditions, and a stagnant and contaminated water supply combined to create ideal circumstances for the proliferation of both pathogens and vectors, setting the stage for the many public health crises that plagued Philadelphia for more than one hundred years. This study uses an ecological perspective to understand how disease worked in Philadelphia. The idea that disease is virtually always a result of the interplay of the environment, the genetic and physical make-up of the individual, and the agent of disease is one of the most important cause and effect ideas underpinned by epidemiology. This dissertation integrates methods from the health sciences, humanities, and social sciences to demonstrate how disease "emergence" in Philadelphia was a dynamic feature of the interrelationships between people and their socio-cultural and physical environments. Classic epidemiological theory, informed by ecological thinking, is used to revisit the city's reconstructed demographic data, bills of mortality, selected diaries (notably that of Elizabeth Drinker), personal letters, contemporary observations and medical literature. The emergence and spread of microbial threats was driven by a complex set of factors, the convergence of which lead to consequences of disease much greater than any single factor might have suggested. Although it has been argued that no precondition of disease was more basic than poverty in eighteenth-century Philadelphia, it is shortsighted to assume that impoverishment was a necessary co-factor in the emergence and spread of disease. The urban environment of Philadelphia contained the epidemiological factors necessary for the growth and propagation of a wide variety of infectious agents, while the social, demographic and behavioral characteristics of the people of the city provided the opportunity for "new" diseases to appear.