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.
Browse
8 results
Search Results
Item THE LONG TAIL OF HISTORY: COMBINING THE 1940 CENSUS, REDLINING MAPS, AND HRS: METHODS FOR ANALYZING THE IMPACT OF REDLINING ON HEALTH, ECONOMIC, AND HEALTHCARE OUTCOMES IN OLDER ADULTS TODAY(2023) Huang, Shuo Jim; Sehgal, Neil J; Health Services Administration; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)ABSTRACTTitle of Dissertation: THE LONG TAIL OF HISTORY: COMBINING THE 1940 CENSUS, REDLINING MAPS, AND HRS: METHODS FOR ANALYZING THE IMPACT OF REDLINING ON HEALTH, ECONOMIC, AND HEALTHCARE OUTCOMES IN OLDER ADULTS TODAY Shuo Huang, Doctor of Philosophy, 2023 Dissertation directed by: Neil Jay Sehgal, PhD, MPH Department of Health Policy Management BackgroundAs part of the New Deal in the 1930s, the Federal government used the Home Owners’ Loan Corporation (HOLC) to draw real estate security maps that were color coded or redlined to discourage lending in majority Black neighborhoods. Redlined areas still have worse health and economic outcomes in the present day. Current literature is focused on present-day residents of redlined areas. Tracking exposures to redlining and conditions of redlining close to the 1930s with present-day health is an unexplored area. Methods We utilize geo-referenced 1930s HOLC maps to locate individuals and map demographic considerations. We use novel algorithmic solutions to geolocate unknown 1940 enumeration districts. Using a 1940 census-linked sample of the Health and Retirement Study to locate individuals in HOLC areas at the time, we conduct survival analysis on HOLC categories’ effect on age at death as well as other analysis on health, economic, and healthcare utilization in the near present. We test for a potential mediator. Results Population density is not associated with either HOLC category or present day life expectancy, and is unlikely to be a mediator. In uncontrolled models, for HRS individuals in the 1940 census HOLC category is associated with greater hazards, worse odds of self-rated health, and worse economic outcomes. With controls, HOLC category is only associated with worse odds of self-rated health. HOLC category is not associated with health insurance or healthcare utilization in this sample. Conclusion Redlining is associated with health and economic outcomes which are attenuated when controlling for likely pathways between redlining and health. Future research should focus on whether individuals stay in redlined areas, and on identifying policy and initial state matrix that can describe what redlining may be a proxy for.Item INVESTIGATING MODEL SELECTION AND PARAMETER RECOVERY OF THE LATENT VARIABLE AUTOREGRESIVE LATENT TRAJECTORY (LV-ALT) MODEL FOR REPEATED MEASURES DATA: A MONTE CARLO SIMULATION STUDY(2023) Houser, Ari; Harring, Jeffrey R; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Over the past several decades, several highly generalized models have been developed which can reduce, through parameter constraints, to a variety of classical models. One such framework, the Autoregressive Latent Trajectory (ALT) model, is a combination of two classical approaches to longitudinal modeling: the autoregressive or simplex family, in which trait scores at one occasion are regressed on scores at a previous occasion, and latent trajectory or growth curve models, in which individual trajectories are specified by a set of latent factors (typically a slope and an intercept) whose values vary across the population.The Latent Variable-Autoregressive Latent Trajectory (LV-ALT) model has been recently proposed as an extension of the ALT model in which the traits of interest are latent constructs measured by one or more indicator variables. The LV-ALT is presented as a framework by which one may compare the fit of a chosen model to alternative possibilities or use to empirically guide the selection of a model in the absence of theory, prior research, or standard practice. To date, however, there has not been any robust analysis of the efficacy or usefulness of the LV-ALT model for this purpose. This study uses a Monte Carlo simulation study to evaluate the efficacy of the basic formulation of the LV-ALT model (univariate latent growth process, single indicator variable) to identify the true model, model family, and key characteristics of the model under manipulated conditions of true model parameters, sample size, measurement reliability, and missing data. The performance of the LV-ALT model for model selection is mixed. Under most manipulated conditions, the best-fitting of nine candidate models was different than the generating model, and the cost of model misspecification for parameter recovery included significant increases in bias and loss of precision in parameter estimation. As a general rule, the LV-ALT should not be relied upon to empirically select a specific model, or to choose between several theoretical plausible models in the autoregressive or latent growth families. Larger sample size, greater measurement reliability, larger parameter magnitude, and a constant autoregressive parameter are associated with greater likelihood of correct model selection.Item INVESTIGATING INDIVIDUAL DIFFERENCES’ PREDICTION OF LANGUAGE PROFICIENCY OUTCOMES: A LATENT GROWTH CURVE MODELING APPROACH(2023) Rhoades, Elizabeth Rogler; Gor, Kira; Clark, Martyn; Second Language Acquisition and Application; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Although decades of research within the field of second language acquisition have been dedicated to investigating the impact of individual differences on second language learners’ success, longitudinal research focused on individual differences and their impact on adult second language acquisition is extremely limited. Additional longitudinal research on individual differences is necessary to further our understanding of the nature of the process of adult second language acquisition. This area of research is also critical to the U.S. Government and the Department of Defense as thousands of military service members work in language-related positions, and these service members’ maintenance of high levels of language proficiency is critical for our nation’s national security. The current study used a longitudinal design to investigate the impact of individual differences such as general cognitive ability, language aptitude, and attitude toward learning assigned second language (L2) on military service members’ language proficiency outcomes. Latent growth curve modeling (LGM) was used to model participants’ initial proficiency levels and growth trajectories, and measures of cognitive ability, language aptitude, and attitude toward learning assigned L2 were used to measure the impact of these individual differences on language proficiency outcomes. Additional variables including GPA, age, education level, number of language training hours, billet type, and sex were also included in the analyses. The results from the four phases of analyses support the conclusion that the predictive value of individual difference factors on language proficiency outcomes differ not only by DLI Language Difficulty Category, as suggested by previous research, but also by language and even language modality.Item Examining the co-development of episodic memory and hippocampal subfields – A longitudinal study(2020) Canada, Kelsey Leigh; Riggins, Tracy; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Episodic memory is a cornerstone ability that allows one to recall past events and the context in which they occur. Many different tasks have been used to assess the development of episodic memory during early childhood. Previous longitudinal work on individual tasks has noted accelerated changes from approximately 5 to 7 years, suggesting non-linear changes in memory ability during early childhood. However, the extent to which tasks relate to one another and are indicative of the latent construct of episodic memory is not known. Further, improvements in memory are thought to relate to underlying changes occurring in the functionally distinct subfields of the hippocampus (i.e., CA2-4/dentate gyrus (DG), CA1, and Subiculum) during this developmental period. This study examined changes in episodic memory ability, hippocampal subfield volume, and the relation between changes in episodic memory and volume of hippocampal subfields during early childhood (4 to 8 years) using longitudinal data and a structural equation modeling framework. Results suggest that episodic memory ability improves substantially during this period, with consistent improvements between 4 to 8 years. Further, there are robust increases in subiculum, CA1, and CA2-4/DG volume between 5 to 6 years of age. Finally, within this sample, there were relations between the development of hippocampal subfields and improvements on a single source memory task commonly used to assess episodic memory. Interestingly, this relation was most robust between subiculum and source memory. Overall, these results highlight the ability to use laboratory tasks to characterize developmental changes in episodic memory, highlight 5- to 6-years as a period of developmental change in hippocampal subfields, and further support a role of the hippocampus in supporting episodic memory.Item Psychological and Neurobiological Outcomes of Parent-Child Adrenocortical Concordance(2017) Merwin, Stephanie; Dougherty, Lea R; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Emerging work has examined parent-child concordance of hypothalamic-pituitary-adrenal (HPA) axis functioning (i.e., adrenocortical concordance) which reflects the attunement or association of the stress hormone cortisol between the parent and child. The cortisol awakening response (CAR) is a critical aspect of HPA axis functioning that is sensitive to environmental factors and uniquely predicts psychopathology in youth. HPA axis functioning has also been linked to alterations in brain structure, specifically the hippocampus. The hippocampus is a critical brain region involved in learning and emotional processing and is sensitive to the parenting context, and undergoes change across early childhood. Despite these critical links between the parent-child dyad, HPA axis functioning, and hippocampal structure, no study has examined the longitudinal outcomes of adrenocortical concordance. The current study examined early parent-child adrenocortical concordance and its concurrent and longitudinal associations with parenting and children’s psychopathology and psychosocial functioning, as well as its longitudinal associations with children’s hippocampal structure in middle childhood. Participants included 142 parent-child dyads. Parents and children provided cortisol at Wave 1 when children were 3-5 years-old, and 98 dyads returned for the Wave 2 assessment three years later when children were 5-9 years-old. At Wave 1, parents and children provided salivary cortisol samples at waking, and 30 and 45 minutes post-waking across two days to assess the CAR. At Waves 1 and 2, child psychopathology and functioning were assessed through a parent-report clinical interview, and the parenting context was assessed through a laboratory-based parent-child interaction task. At Wave 2, a subsample of 51 children completed an anatomical magnetic resonance imaging assessment to measure hippocampal structure. Stronger parent-child concordance was associated with children’s poorer outcomes, namely increases in parental hostility from early to middle childhood, and children’s greater psychiatric symptoms and poorer psychosocial functioning in early and middle childhood. Moreover, parent- and child-level risk factors moderated several associations between stronger concordance and children’s poor outcomes. Parent-child concordance was not related to children’s hippocampal volumes in middle childhood. Importantly, our findings highlight adrenocortical concordance as a process underlying the parent-child relationship that plays a role in the development of psychopathology and functional impairment in children.Item A POSITIVE MODEL OF ROUTE CHOICE BEHAVIOR AND VALUE OF TIME CALCULATION USING LONGITUDINAL GPS SURVEY DATA(2012) Krause, Cory; Zhang, Lei; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis approaches the topic of value of time calculation and route choice behavior with a new and innovative methodology using a survey dataset that was uniquely designed and implemented for this purpose. The survey is a 70 day, 218 participant GPS travel survey used to track individual location constantly at one minute intervals. Using a positive behavior theory framework, an in depth knowledge database for each user is created that iteratively updates the learned behavior and experienced travel conditions for each trip the user takes. A new approach for calculating value of time is presented; using the cost and trip duration of previous trips. The bounds (or caps and floors) are averaged to achieve the individual's value of time based upon their route (and therefore cost) decisions. Also using this updating knowledge base, route decision rules are derived using machine learning algorithms to tell why a user has decided to take the toll road option for certain days, and under what conditions the user will not take the toll road option. The final contribution is a model that fully takes advantage of longitudinal GPS data to create an adaptive system for value of time calculation and positive route decision making.Item SEMIPARAMETRIC AND NONPARAMETRIC ANALYSIS FOR LONGITUDINAL DATA ON THE RELATIONSHIP BETWEEN CHILDHOOD EXTERNALIZING BEHAVIOR AND BODY MASS INDEX(2011) Wang, Kejia; He, Xin; Epidemiology and Biostatistics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis is an extension of the longitudinal data analysis of the association between externalizing behavior in early childhood and body mass index (BMI) from age 2 to 12 years conducted in Anderson et al. (2010). Externalizing behaviors problems are characterized by aggressive, oppositional, disruptive, or inattentive behaviors beyond those that would be expected given a child's age and development. The aim of the thesis is to estimate the children's BMI trajectory and to evaluate to what extent the externalizing behavior is related to BMI using semiparametric and nonparametric time-varying coefficient models. Some valuable insights into how the externalizing behavior and BMI are associated will be provided.Item Infant speech perception in noise and early childhood measures of syntax and attention abilities(2008) Blayney, Elizabeth Sarah Sanford; Newman, Rochelle; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Childhood outcomes in syntactic and attention abilities were measured for 23 children (mean age = 5:3) who, as infants, had either succeeded or failed at identifying their name in the presence of multitalker background noise. Children from the unsuccessful infant group were rated by parents as having significantly more difficulty with attention-related behaviors than children from the successful infant group. The two groups did not perform significantly differently on standardized measures of morphosyntactic ability, but the unsuccessful group was found to have significantly lower MLUs on narrative language samples than the successful group.