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 Essays on Political Economy of Development in Latin America(2024) Angulo Santacruz, Juan Carlos; Battistin, Erich; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation is composed of three applied economics essays in the intersection of development economics and political economy. The first provides an economic explanation to the increase in the intensity of conflict. The second focuses on the effects of presence of illegal activities on educational outcomes. The third analyzes the effect of mass migration on voting behavior and political preferences. Chapter 1 studies how crime may be an unintended consequence of local development. The surge in global demand for Mexican avocados, particularly from the United States, has led to increased production and revenue in avocado-producing municipalities of Mexico. I show that these external changes in avocado global consumption patterns have influenced conflict levels in Mexico. Combining geographical variations in avocado cultivation suitability and fluctuations in avocado demand over time, I find a notable rise in homicides among agricultural workers in municipalities that are well-suited for avocado production. I demonstrate that this rise in homicides is not explained by the increased presence of drug cartels but rather heightened competition between cartels for resources in municipalities where avocados are produced. These findings suggest that cartels vie for territorial control, diversifying their income sources, including the avocado industry, in response to their relatively limited influence over drug markets and routes. In Chapter 2, I turn my attention to the production of illegal crops and how it affects schooling decisions. I focus on the case of Colombian coca leaves, the main input to produce cocaine. The country's main strategy to eradicate coca crops was the fumigation of herbicide until 2015, when the practice was banned. I exploit a plausible exogenous variation in the probability of being sprayed and the temporal effects of the fumigation campaigns as an instrument for the presence of coca fields. This temporal variation along with the cross-sectional variation of the spraying campaigns lead to an instrumental variable difference-in-differences. I use data on coca presence, eradication missions, and school outcomes at the municipal level from 2012 to 2018 to test whether a change in the presence of coca crops has an effect on schooling decisions. I show that my setting does not meet all the assumptions of the traditional difference-in-differences strategy but it fits those of Fuzzy Difference-in-Differences. My empirical findings suggest that an increase in the area cultivated with coca crops increases the high-school dropout rate and it has no effect on the enrollment rate. I rule out the possibility that coca presence crowds out other legal crops. Taken together, these results suggest that high school-age individuals are leaving school to work on coca related activities. In Chapter 3, I revisit the question on whether political preferences of voters are molded by the presence of migrants. I exploit the unanticipated inflow to Colombia of Venezuelans fleeing their home country's political crisis in 2016 and the onset of economic collapse. I compare the results of the 2018 presidential campaign in Colombia across municipalities with similar trends in electoral outcomes between 2002 and 2014 but different presence of Venezuelan migrants on the verge of the 2018 campaign. To address the spatial sorting of migrants across these municipalities, I construct an instrumental variable based on the distance from the closest ports of entry. I find that an increase in the presence of migrants in the municipality yielded a polarized voting behavior. I show that these effects are explained by an increase in the electoral turnout, and that the fondness of voters for Colombia's 2016 Peace Agreement Plebiscite was an important determinant of their behavior, which has been overlooked in past empirical work.Item CHRONIC SUFFERING: CHRONIC ILLNESS, DISABILITY, AND VIOLENCE AMONG MEXICAN MIGRANT WOMEN(2022) Guevara, Emilia Mercedes; Getrich, Christina M; Anthropology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation seeks to better understand how Mexican migrant women who work in the Maryland crab industry make sense of chronic illnesses such as diabetes, asthma, and musculoskeletal pain while at the same time living spatially and temporally complicated lives as circular temporary migrant laborers. I explore how immigration and labor policies and practices, constrained and conditional access to resources and care, and exposure to multiple forms of violence structure their chronic illness experiences and entanglements of biological and social processes that intersect. Together, these embodied biological and social processes coalesce into what I describe as problemas crónica-gendered “chronic problems” – and other disruptions that migrant women endure across time and transnational space. I describe how problemas crónicas manifest themselves throughout the lives and migratory careers of Mexican migrant women and how they grapple with obstacles as they seek care, renegotiate their identities, and re/build their lives.Item UNDERSTANDING FUNCTIONAL BEHAVIORS OF ORGANOTROPIC TRIPLE NEGATIVE BREAST CANCER CELLS(2023) DeCastro, Ariana Joy; Stroka, Kimberly M; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)11.7% of all cancer cases consist of breast cancer worldwide according to global cancer statistics. Triple negative breast cancer (TNBC) is subtype of breast cancer that has no expression of common hormonal receptors - estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Due to this, TNBC is insensitive to endocrine or molecular targeted therapy and chemotherapy is the most effective treatment. Additionally, TNBC patients have reoccurrence within 3 years of diagnosis. Going further, due to the non-specific targeting of chemotherapy, cancer cells can develop drug resistance. The gold standard does not work in conjunction with microenvironmental factors to reduce disease progression and drug resistance. Not only is this disease lacking in effective treatments but is associated with a health disparity being most prevalent in pre-menopausal and African American women. There is clearlya need to understand the mechanisms of TNBC metastasis because of the impact not only on women in general but on women in historically marginalized communities. A significant innovation in determining cancer treatment is the use of genomic sequencing to identify mutations associated with metastasis. However, tumor heterogeneity puts limitations on fully understanding genomic landscape of TNBC, a highly mutational disease, using sequencing. Further, even when mutations are identified they may not be targetable, or patients may not respond to treatments. While genomic sequencing can be beneficial in improving treatment outcomes, they require further downstream validation of genetic expression to completely understand tumor biology and metastatic progression. This is where understanding the functional behavior of tumor cells with respect to their preferred secondary microenvironment can be advantageous in supplementing genomics data to get a comprehensive understanding of TNBC metastasis. The overall goal of this dissertation is to address this gap by quantifying tumor cell functional behavior and their response to microenvironmental cues. We evaluate three different physical and biochemical behaviors of TNBC tumor cells. In Chapter 3, the effect of TNBC secretome on endothelial barrier properties and function is explored. Chapter 4 quantifies the morphological and migratory phenotypes of brain and bone-seeking TNBC cells in response to ECM protein substrates found in their relevant microenvironments. Lastly, Chapter 5 will quantify the TNBC incorporation in response to brain relevant microenvironmental cues. Quantifying these functional behaviors could provide indicators of brain and bone tropic metastatic behavior and have broader impacts in creating a complete physical profile of organotropic TNBC metastasis.Item CONCENTRATION- AND TIME-DEPENDENT EFFECTS OF PROGESTERONE ON ENDOTHELIAL CELLS(2022) Kim, Katherine In-Wha; Prior, Steven J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The termination of endogenous sex hormone release is thought to account for increases in cardiovascular disease (CVD) incidence in postmenopausal women. Thus, hormone replacement therapy may be a preventive measure against cardiovascular disease. To date, most research has been focused on estrogen treatment, but the effects of progesterone, a vasoactive hormone with effects on the endothelium, have received less attention. Two progesterone receptor subtypes, nuclear and membrane, are known to enact the effects of progesterone in endothelial cells which mediate the release of nitric oxide (NO). There is also some evidence that the two subtypes function in a coordinated manner. The aims of this thesis study are to assess the effects of different concentrations of progesterone on endothelial cells and isolate the actions of the progesterone receptor subtypes. Outcomes of this study include migration and proliferation assays to assess endothelial cell function and Western blotting to quantify endothelial nitric oxide synthase expression and phosphorylation. Progesterone and the membrane progesterone receptor agonist were found to inhibit migration and proliferation of human umbilical vein endothelial cells (HUVECs), while progesterone alone or in combination with the membrane progesterone receptor agonist increased endothelial nitric oxide synthase (eNOS) phosphorylation in HUVECs after 24 hours of incubation. While increased eNOS phosphorylation is thought to be beneficial to HUVEC function, other factors released in the presence of progesterone or progesterone receptor agonists may be scavenging bioavailable NO, thus reducing the angiogenic potential of HUVECs.Item CONTEXTUALIZING DRIVERS AND OUTCOMES OF RURAL-TO-URBAN MIGRATION: LESSONS FROM MOZAMBIQUE(2021) Anderson, Kelly Jean; Silva, Julie A; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Migration is a critical strategy for households negotiating environmental risk, yet the extent to which it represents an adaptation remains poorly understood. This dissertation research investigates the relationship between migration and climate change vulnerability using examples from two rural-to-urban migrant communities located in the coastal city of Beira, Mozambique. In order to understand the extent to which adverse weather influences migration decision-making and the vulnerability to climate change experienced by migrants relative to non-migrants, perceptions and lived experiences of adverse weather are explored. Over 2,500 households were mapped from which semi-structured interviews and surveys were conducted with a random sample of migrant (n=79) and non-migrant (n=79) households. Content analysis and descriptive statistics reveal (1) the weather’s influence on rural-to-urban migration falls on a spectrum of attribution, (2) most migrants relocate in response to the impoverishing effects of weather, (3) migrants and non-migrants experience comparable levels of environmental vulnerability in urban settings, and (4) neighborhood characteristics are significant in shaping experiences of urban flood vulnerability. Results indicate that people prefer in situ adaptation regardless of extreme weather, provided resilient economic livelihoods exist and government is held accountable. Decolonizing research methodologies offer a promising path forward to better understand the needs of those vulnerable to climate change and facilitate adaptation to climate change.Item THE IMPACT OF ENGINEERED MECHANICAL CONFINEMENT ON MESENCHYMAL STEM CELL AND LUNG FIBROBLAST MECHANOBIOLOGY(2020) Doolin, Mary; Stroka, Kimberly M; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Mechanical cues have been shown to influence cell gene expression, cell protein expression, and cell behaviors critical for homeostasis and disease progression. Cells experience the mechanical cue of confinement in vivo, such as within the extracellular matrix, and in vitro, such as within tissue engineered scaffolds. Despite its prevalence, the impact of mechanical confinement on cell fate is poorly understood. Cues from the mechanical microenvironment are primarily sensed and responded to by the cytoskeleton, which transmits forces to the nucleus and can thereby alter gene expression. The nucleus itself is also a mechanosensor, sensing external forces and again altering gene expression. Mesenchymal stem cells (MSCs) and lung fibroblasts are known to be sensitive to mechanical forces, yet the effect of mechanical confinement on these cells is unclear. In this dissertation, we investigated how mechanical confinement induced by engineered microchannels influences MSC morphology and migration. Notably, we show that confinement alters the relative contributions of cytoskeletal and contractile machinery in MSC migration in unconfined and confined spaces. We next investigated how mechanical confinement induced by microchannels influences MSC and fibroblast nucleus volume. When certain cytoskeletal machinery was inhibited, nucleus volume was altered only in MSCs in wide channels, suggesting diverging roles of the cytoskeleton in regulating nuclear deformation and migration in different degrees of confinement and in different cell types. While performing this work, we observed a lack of assays that provide precise control over the degree of confinement induced on cells, yield a large sample size, enable long-term culture, and enable easy visualization of cells over time. Therefore, we designed, created, and validated a confining micropillar assay that achieves these requirements. Using these confining micropillars, we investigated the effect of confinement on lung fibroblast to myofibroblast transition (FMT), a hallmark of idiopathic pulmonary fibrosis. Cell density was more predictive of FMT than the degree of confinement induced by micropillar arrays. These results improve our understanding of how MSCs and lung fibroblasts respond to confinement, which will aid in the rational design of MSC-based therapies and FMT-targeting therapies.Item MULTICULTURAL POLITICS AND NATIONAL BOUNDARY MAKING IN KOREA: Mapping the intersectional dimensions of nation, gender, class, and ethnicity in state policy and practice(2019) Yu, Sojin; Marsh, Kris; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the conception and implementation of state multicultural policy to analyze how migrants are received and incorporated within South Korea, a newly emergent migrant receiving country in Asia. To this end, I conducted ethnographic research at two Centers established to enact governmental multicultural policy, focusing on the separate accounts and experiences of ground-level policy practitioners (Koreans) and targeted recipients (migrants) in relation to the policy implementation and its ‘real world’ effects. The results show the varied and conflicting perspectives of those involved, and how they are informed by the intersecting social constructs of nation, ethnicity, gender, family, and class. These intersectional workings and effects also contribute to the unequal social relations between Koreans and migrants, especially in shaping a particular national form of ‘racism’ against migrants, and helping to maintain the previously unchallenged formation of national identity in Korea. Three thematically arranged analysis chapters discuss specifically how these social processes serve to form and naturalize social hierarchies and powers in Korea, with each chapter examining a specific intersectional circumstance: The intersection of gender inequality and nationalism; the intersection of class and nation(ality); and, the emphasis of joint Korean nationality and ethnicity in the multicultural policy. Each chapter illustrates the predominance of nationalism, as the critical mechanism and rationale behind Korea’s contested multicultural politics, and the central axis to connect with other dimensions of power including gender, class, and ethnicity. The combined research outcomes reveal the complex ways in which the inter-group relations and hierarchies are organized, through the state policy, bureaucratic practice and individual agency.Item Bodies on the Line: Violence, Disposable Subjects, and the US-Mexico Border Industrial Complex(2016) Perez, Cristina Jo; Rowley, Michelle V; Women's Studies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Bodies On the Line: Violence, Disposable Subjects, and the Border Industrial Complex explores the construction of identity and notions of belonging within an increasingly privatized and militarized Border Industrial Complex. Specifically, the project interrogates how discourses of Mexican migrants as racialized, gendered, and hypersexualized “deviants” normalize violence against border crossers. Starting at Juárez/El Paso border, I follow the expanding border, interrogating the ways that Mexican migrants, regardless of sexual orientation, have been constructed and disciplined according to racialized notions of “sexual deviance." I engage a queer of color critique to argue that sexual deviance becomes a justification for targeting and containing migrant subjects. By focusing on the economic and racially motivated violence that the Border Industrial Complex does to Mexican migrant communities, I expand the critiques that feminists of color have long leveraged against systemic violence done to communities of color through the prison industrial system. Importantly, this project contributes to transnational feminist scholarship by contextualizing border violence within the global circuits of labor, capital, and ideology that shape perceptions of border insecurity. The project contributes an interdisciplinary perspective that uses a multi-method approach to understand how border violence is exercised against Mexicans at the Mexico-US border. I use archival methods to ask how historical records housed at the National Border Patrol Museum and Memorial Library serve as political instruments that reinforce the contemporary use of violence against Mexican migrants. I also use semi-structured interviews with nine frequent border crossers to consider the various ways crossers defined and aligned themselves at the border. Finally, I analyze the master narratives that come to surround specific cases of border violence. To that end, I consider the mainstream media’s coverage, legal proceedings, and policy to better understand the racialized, gendered, and sexualized logics of the violence.Item ESSAYS ON DISPLACED WORKERS AND RESIDENTIAL MIGRATION(2016) Ueda, Ken Masahiro; Hellerstein, Judith; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In this dissertation, I explore how workers’ human capital, local industry composition, and business cycles affect employment outcomes and residential migration for job losers and other workers. I first examine whether the poor employment outcomes of job losers are due to a lack of jobs that require their human capital within their local labor market. I answer this question by analyzing the extent to which the industry composition in the job loser’s local labor market affects employment outcomes when job loss occurs during expansions and during recessions. I find that if job losers reside in an area with a high employment concentration of their original industry of employment, they are 2.1-2.8 percent more likely to be re-employed at another job if job loss occurs during an expansion; I find an insignificant relationship in most specifications when job loss occurs during a recession, and in some specifications I even find a negative relationship between industry concentration and employment. I conclude that the industry composition within an area matters for job losers, since firms are more willing to hire workers from within their own industry, as these workers have more relevant accumulated human capital. However, firms are less likely to hire during a recession, making job losers’ human capital less important for job finding. Next, Erika McEntarfer, Henry Hyatt, and I examine whether the business cycle affects earnings changes for job losers, and the factors that explain these differences across time. We find that job losers who lost their job during the Great Recession have earnings changes that are 10 percent more negative relative to other job losers from other periods. This result is driven primarily by longer nonemployment lengths and worse subsequent job matches. Finally, Erika McEntarfer, Henry Hyatt, Alexandria Zhang, and I explore the extent to which residential migration is driven by job opportunities. We use four databases and find that changes in job moves explain some of the changes in residential migration, but the relationship is not as strong as previously documented. We find that migration patterns differ across databases, with some databases documenting steeper declines and more cyclicality.Item Studying the Causes and Consequences of Internal Labor Migration Using Survey and Administrative Data Sources(2016) Goetz, Christopher F.; Haltiwanger, John; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation comprises three chapters. The first chapter motivates the use of a novel data set combining survey and administrative sources for the study of internal labor migration. By following a sample of individuals from the American Community Survey (ACS) across their employment outcomes over time according to the Longitudinal Employer-Household Dynamics (LEHD) database, I construct a measure of geographic labor mobility that allows me to exploit information about individuals prior to their move. This enables me to explore aspects of the migration decision, such as homeownership and employment status, in ways that have not previously been possible. In the second chapter, I use this data set to test the theory that falling home prices affect a worker’s propensity to take a job in a different metropolitan area from where he is currently located. Employing a within-CBSA and time estimation that compares homeowners to renters in their propensities to relocate for jobs, I find that homeowners who have experienced declines in the nominal value of their homes are approximately 12% less likely than average to take a new job in a location outside of the metropolitan area where they currently reside. This evidence is consistent with the hypothesis that housing lock-in has contributed to the decline in labor mobility of homeowners during the recent housing bust. The third chapter focuses on a sample of unemployed workers in the same data set, in order to compare the unemployment durations of those who find subsequent employment by relocating to a new metropolitan area, versus those who find employment in their original location. Using an instrumental variables strategy to address the endogeneity of the migration decision, I find that out-migrating for a new job significantly reduces the time to re-employment. These results stand in contrast to OLS estimates, which suggest that those who move have longer unemployment durations. This implies that those who migrate for jobs in the data may be particularly disadvantaged in their ability to find employment, and thus have strong short-term incentives to relocate.