Theses and Dissertations from UMD
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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
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Item Understanding the Risk of Drug Overdose and Alcohol-Induced Deaths Among Adults with Different Types of Disabilities(2023) Aram, Jonathan; Dallal, Cher M; Epidemiology and Biostatistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: Disability is associated with drug and alcohol morbidity and mortality, which have reached high levels in recent years. Previous disability studies often combine all disabilities into a single category or focus on a single type of limitation. This dissertation characterizes different types of disabilities among U.S. adults and assesses associations with drug and alcohol morbidity and mortality. Methods: Using the 2018-2019 National Survey on Drug Use and Health (NSDUH, Aim 1), a nationally representative cross-sectional survey (n=83,485), different individual disabilities and co-occurring disabilities were identified. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for associations between disability type and prevalence of drug and alcohol use disorders. Disabilities were also characterized within the Mortality Disparities in American Communities Study (Aims 2 and 3), a nationally-representative prospective cohort with baseline data collected in 2008 and mortality follow-up through 2019 (n=3,324,000). Multivariable Cox proportional hazards regression was used to estimate adjusted hazard ratios (aHRs) and CIs for associations between disability type and drug overdose death (OD, Aim 2) and alcohol-induced death (AID, Aim 3). Results: Within the NSDUH analysis, adults with cognitive disability had increased odds of drug (aOR=3.3; 95% CI=2.9–3.8), and alcohol use disorder (aOR=2.3; 95% CI=2.0–2.6), compared to adults without disability. Positive associations of lesser magnitude were observed between hearing/seeing and ambulatory disabilities and drug use disorder. In MDAC analyses, OD risk was elevated among adults with cognitive (aHR=2.6; 95% CI=2.4–2.9), ambulatory (aHR=2.8; 95% CI=2.6–3.1), ambulatory and hearing/seeing (aHR=2.5; 95% CI=2.0–3.1), and hearing/seeing disability (aHR=1.6; 95% CI=1.4–1.9), compared to adults without disability. The risk of AID was elevated for adults with co-occurring ambulatory and hearing/seeing disability (aHR=1.8; 95% CI=1.5–2.2), ambulatory disability only (aHR=1.5; 95% CI=1.3–1.7), and hearing/seeing disability only (aHR=1.2; 95% CI=1.0–1.4). Conclusions: The examination of specific disability categories reveals unique associations that are not apparent when all disabilities are combined. These findings can be used to improve access to recovery support services. Expansion of educational and occupational opportunities for adults with disabilities should be considered as strategies to reduce drug and alcohol morbidity and mortality.Item BALD EAGLES (HALIAEETUS LEUCOCEPHALUS) AS INDICATORS OF GREAT LAKES ECOSYSTEM HEALTH(2016) Simon, Kendall Lyn; Bowerman, William W; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Environmental indicators have been proposed as a means to assess ecological integrity, monitoring both chemical and biological stressors. In this study, we used nestling bald eagles as indicators to quantify direct or indirect tertiary-level contaminant exposure. The spatial and temporal trends of polychlorinated biphenyl (PCB) congeners were evaluated in nestling plasma from 1999–2014. Two hexa-chlorinated congeners, PCB-138 and 153, were detected with the highest frequency and greatest concentrations throughout Michigan. Less-chlorinated congeners such as PCB-52 and 66 however, comprised a greater percentage of total PCB concentrations in nestlings proximate to urbanized areas, such as along the shorelines of Lake Erie. Toxic equivalents were greatest in the samples collected from nestlings located on Lake Erie, followed by the other Great Lakes spatial regions. Nestling plasma samples were also used to measure concentrations of the most heavily-used group of flame retardants, brominated diphenyl ethers (BDEs), and three groups of alternative flame retardants, non-BDE Brominated Flame Retardants (NBFRS), Dechloranes, and organophosphate esters (OPs). BDE-47, 99 and 100 contributed the greatest to total BDE concentrations. Concentrations of structurally similar NBFRs found in this study and recent atmospheric studies indicate that they are largely used as replacements to previously used BDE mixtures. A variety of Dechloranes, or derivatives of Mirex and Dechlorane Plus, were measured. Although, measured at lesser concentrations, environmental behavior of these compounds may be similar to mirex and warrant future research in aquatic species. Concentrations of OPs in nestling plasma were two to three orders of magnitude greater than all other groups of flame retardants. In addition to chemical indicators, bald eagles have also been proposed as indicators to identify ecological stressors using population measures that are tied to the fitness of individuals and populations. Using mortality as a population vitality rate, vehicle collisions were found to be the main source of mortality with a greater incidence for females during white-tailed deer (Odocoileus virginianus) hunting months and spring snow-melt. Lead poisoning was the second greatest source of mortality, with sources likely due to unretrieved hunter-killed, white-tailed deer carcasses, and possibly exacerbated by density-dependent effects due to the growing population in Michigan.Item Empirical Essays on Disability Insurance, Employment and Health(2012) Moore, Timothy John; Kearney, Melissa S; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The optimal design of tax and transfer policies involves understanding how income payments affect the behavior of recipients. This dissertation contributes to the public economics literature by examining how various income payments affect employment and health. The first chapter is focused on the relationship between disability payments and employment. The other two chapters explore short-term patterns in mortality and the role of income payments, which advances our understanding of the broader relationship between income and health. Chapter 1: The Employment Effects of Terminating Disability Benefits: Insights from Removing Drug and Alcohol Addictions as Disabling Conditions A challenge in designing return-to-work policies for Social Security Disability Insurance or Supplemental Security Income disability beneficiaries is identifying who is able to work. Using administrative data, I estimate the employment effects resulting from the 1996 removal of drug and alcohol addictions as disabling conditions, which eliminated the benefits of approximately 100,000 individuals. Terminated beneficiaries' employment increased by 20-30 percentage points, which is large relative to their work histories. The heterogeneity in employment is consistent with program participation initially increasing employment potential, before being outweighed by the negative consequences of being out of the labor force. Chapter 2: Liquidity, Economic Activity, and Mortality (with William N. Evans) We document a within-month mortality cycle where deaths decline before the first day of the month and spike after the first. This cycle is present across a wide variety of causes and demographic groups. A similar cycle exists for a range of economic activities, suggesting the mortality cycle may be due to short-term variation in levels of economic activity. Our results suggest a causal pathway whereby liquidity problems reduce activity, which in turn reduces mortality. These relationships may help explain the pro-cyclical nature of mortality. Chapter 3: The Short-term Mortality Consequences of Income Receipt (with William N. Evans) Researchers and retailers have documented that consumption declines before the receipt of income, and then rises afterwards. We identify a related phenomenon, where mortality rises immediately after income receipt. We find that mortality increases following the arrival of monthly Social Security payments, regular wage payments for military personnel, the 2001 tax rebates, and Alaska Permanent Fund dividend payments. The increase in short-run mortality is large, and occurs for a large number of causes of death.