Theses and Dissertations from UMD
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Item Examining the Joint Contribution of Trauma and Adverse Neighborhood Characteristics to Paranoid Ideation: A Multi-Method Approach in a Transdiagnostic Sample.(2024) Todd, Imani; Blanchard, Jack J; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Paranoid ideation is common in psychosis and is associated with impairment. Multiple cognitive factors influence paranoid ideation, including lack of belief flexibility and hostile attributions. Separately, negative affect precedes and maintains later paranoid ideation. Research on what provokes these cognitive and affective biases highlights the influence of trauma and environmental stress. Traumatic experiences are a reliable risk factor for psychotic disorders and suspiciousness. Prior literature examining trauma and paranoid ideation only uses broad indicators of positive symptoms or single-item assessments. Aside from trauma, environmental research identifies two major facets that contribute to the development and maintenance of psychotic symptoms: neighborhood deprivation and crime. Population studies show that individuals who reside in deprived neighborhoods are more likely to experience increased paranoid ideation. Crime may also influence perceptions of threat and hostility and has been related to paranoid ideation. Neighborhood deprivation and crime can be measured through objective assessments and neighborhood perceptions. Evidence suggests that neighborhood perceptions impact paranoid ideation, above and beyond area-level assessments of neighborhood features, but findings vary. Although trauma, neighborhood deprivation, and crime have been shown to impact paranoid ideation, few have examined these constructs in Tandem. The current study seeks to examine the association between individual-level (i.e., trauma, neighborhood perceptions) and system-level (i.e., neighborhood deprivation and crime) factors and paranoid ideation. Results indicated that greater trauma and perceptions of neighborhood violence concurrently contributed to more severe paranoid ideation. However, administrative data on neighborhood deprivation and crime were not related. These results indicate that violence perceptions interact with existing vulnerabilities in exacerbating perpetuating psychotic symptomatology. Thus, interventions focused on reducing paranoia in this population would benefit from considering past traumas and one's current environment.Item Climate Change and Vibrio species: Investigation of Environmental Parameters Associated with Occurrence and Transmission(2023) Brumfield, Kyle David; Colwell, Rita R.; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Climate change, associated with shifts in the geographical range of biological species, has become increasingly important in emergence and re-emergence of disease. Vibrio spp., native to aquatic ecosystems, are commonly associated with aquatic invertebrates, notably crustaceans and zooplankton. Some species of the genus Vibrio cause infection in humans, of which Vibrio cholerae, the etiological agent of pandemic cholera, is the most documented. Pathogenic non-cholera Vibrio spp., namely Vibrio parahaemolyticus and Vibrio vulnificus, cause gastroenteritis and also septicemia and extra-intestinal infections. They are responsible for a large number of public health emergencies in developed countries, including the United States. As sea temperatures rise and salinity profiles are altered, a pattern of poleward spreading of non-cholera Vibrio spp. has been observed globally, demonstrating significant geographic expansion of these bacterial populations, corroborated by an associated increase in the number of reported vibriosis cases. Since Vibrio spp., including pathogenic vibrios, play an important role in the degradation of polymeric substances, such as chitin, and in biogeochemical processes, they cannot be eradicated. Hence, routine monitoring and an early warning system are needed for public health preparedness. Since the 1960’s, ongoing research has focused on environmental factors linked with occurrence and distribution of clinically relevant Vibrio spp. and their role in disease transmission. We have reported that lack of, or damage to, water, sanitation, and hygiene (WASH) infrastructure, coupled with elevated air temperatures, and followed by above average rainfall promotes exposure of a population to contaminated water, hence increases the risk of an outbreak of cholera. Global predictive intelligence models applicable to diseases caused by non-cholera Vibrio spp. are in development. The research reported here describes results of intensive sampling to detect and characterize Vibrio spp. in the Chesapeake Bay, Maryland, and the Florida Gulf Coast, the latter an area significantly impacted by Hurricane Ian, September 2022, with a spike in confirmed vibriosis cases and deaths during weeks following the storm. Results of this study provide confirmation of environmental predictors for Vibrio spp. and document long-term increase and extended seasonality of Vibrio populations in the Chesapeake Bay. Using satellite remote sensing data, we demonstrate the impact of extreme heat, precipitation, and other key environmental and geophysical factors (e.g., temperature, salinity, and chlorophyll) on prevalence of pathogenic Vibrio spp. in aquatic systems. This study lays the groundwork for a predictive intelligence system for Vibrio spp. and other pathogens under varying climatic scenarios.Item ESSAYS ON INTERNATIONAL TRADE AND THE ENVIRONMENT(2022) Lim, Heehyun Rosa; Limão, Nuno; Lee, Eunhee; Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the relationship between international trade and environmental outcomes. In particular, I study the impact of international trade on airborne pollutants, including the change in emissions and concentration as well as their welfare consequences. In the first chapter, I suggest the intermediate import channel as a new perspective to understand the linkage between international trade and air pollutant emissions. I first review the existing literature's understanding of the impact of trade on emissions. The review shows that the literature mostly focuses on the increased market access but overlooks the increased access to imported inputs. Using the data on the US manufacturing industries, I then document a few stylized facts that are suggestive of the linkage between intermediate imports, input usage, and emissions. I show that in the US, the import penetration among inputs used has increased while the energy intensity of US manufacturing has declined, the latter of which explains a third of the within-industry reduction in $NO_x$ emission intensity. To analyze the channels by which trade in intermediate inputs affects emission intensity, I build a model of heterogeneous firms, intermediate trade, and inputs with different emission profiles. By focusing primarily on the emissions linked with input usage, my model examines the effect of improved access to foreign intermediates on firms' input choices and emission outcomes. The model shows that with lower intermediate import costs, firms become less energy-intensive by either increasing their intermediate intensity, using energy-saving technology, or both. Moreover, the general equilibrium force, as well as amplification through the input-output linkage, bring a further decrease in emission intensity in all firms. The model also presents the selection and reallocation effect which further amplifies the within-firm improvements. In the second chapter, I run empirical and quantitative analyses to test the theoretical model from the first chapter against the US manufacturing data. In the empirical analysis, I estimate the model prediction, which states that industry-level emission intensity can be expressed in the producer price index when the cost of energy and market access are controlled,using the industry-level panel data between 1998 and 2014. By using the import price of intermediates as an instrumental variable for the producer price index, I find evidence that a lower producer price, driven by a lower intermediate import price, leads to lower $NO_x$ emission intensity. The reduced-form evidence supports the model mechanism that states that a lower import price of intermediates decreases emission intensity. I then calibrate the model to 1998 aggregate US manufacturing and quantify the change in emission intensity driven by the change in intermediate import cost. The quantification shows that the fall in intermediate import cost between 1998 and 2014 explains about 8-10\% of the observed technique effect in $NO_x$ emissions. 68\% of the decrease comes from the within-firm changes via firms' substituting away from energy inputs, global sourcing, and adopting energy-saving technology, which highlights the importance of taking within-firm channels into account to understand the effects of trade policies on emissions. The third chapter (co-authored) re-examines the welfare gains from international trade by incorporating the transboundary nature of air pollutants.\footnote{This chapter is from a joint work with Eunhee Lee.} We run country-level panel regressions and find that concentration is correlated with transboundary pollution, constructed as the weighted sum of other countries' emissions. We then build a general equilibrium model of international trade and environmental externality from local pollutants of transboundary nature, in which the concentration of a country is affected by both its own and other countries' emissions. The model shows that the change in welfare can be decomposed into the change in real income and the change in air pollutant concentration, the latter of which can further be decomposed into that driven by own emissions and by other countries' emissions. We use this model to quantify the welfare implications of two trade shocks -- China shock and the EU 2004 enlargement. The results show multiple channels that shape heterogeneous welfare consequences across countries. First, liberalizing countries experience an increase in emissions due to an increase in production. Second, the emissions of other countries move in either direction, depending on the effects of pollution relocation and increased production due to cheaper inputs. Third, the levels of concentration increase in liberalized countries and some other countries due to the increase in own emissions or transboundary pollution, or both. We run additional counterfactual exercises with stricter environmental regulations imposed on liberalized countries and show that there can be welfare gains in many countries by lowering emissions and transboundary pollution, suggesting the potential effects of combining trade and environmental policies.Item Understanding Values in Organizational Contexts: The Case of Species Conservation(2021) Dewey, Amanda Michelle Milster; Ray, Rashawn; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Biodiversity loss poses an existential threat to human life, and human activities both intentionally and unintentionally affect other species. Values provide an important tool for explaining such human behavior. While we have evidence of the causes and consequences of wildlife values at the individual level, much human activity that influences wildlife occurs in organizational settings. This project seeks to uncover the roles and negotiation of values in conservation organizations, filling an important research gap. The project uses a case study approach to illuminate the role and negotiation of values in case studies of three wildlife conservation contexts: national wildlife conservation, red wolf conservation, and horseshoe crab conservation in the mid-Atlantic. Through strategic selection of two organizations in each case, I explore how values function in these varied conservation contexts using interviews with staff and volunteers and content analysis of websites and social media. I argue that a broader typology of value frames exists within wildlife conservation organizations than is traditionally discussed in wildlife value literature. I find that frames include moral conservationist, community-steward, and complex utilitarian values, adding nuance to the previously understood value spectrum of humans versus nature. While findings indicated that values were behavior motivators for volunteers, volunteers were more likely to perceive and attempt to construct value alignment than to actively seeking organizations that were compatible with their values. While organizations proclaimed their values and described using values in determining tactics and approaches, they also did not report consciously attempting to align values in processes of volunteer recruitment. Findings indicated differences in value processes in local versus national organizations, and a complex value framing in organizational settings. Despite the fact that the COVID-19 pandemic is an extremely disruptive social event that was directly tied to wildlife and biodiversity issues, this connection was not highlighted equally by volunteers or organizations, nor did organizations equally or significantly respond to a nationwide call to reckon with racial injustice. I argue that the organizations and volunteers who framed their values and approaches more broadly and included moral value of the wellbeing of both humans and other species were more responsive to changing social contexts.Item ESSAYS ON DECOMPOSITION ANALYSIS(2013) Palacios Lopez, Amparo; Lopez, Ramon; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Chapter 1 shows the implications of credit and labor market imperfections on gender differences in agricultural labor productivity, especially highlighting how both imperfections negatively affect female productivity by discouraging off-farm income generating activities and restricting access to inputs. The paper theoretically models the relationship between gender differences in agricultural labor productivity and market imperfections and it provides empirical evidence consistent with our theoretical model by decomposing the contribution of different factors to such gender differences. We find that agricultural labor productivity is on average 44 percent lower on plots belonging to female-headed households than on those belonging to male-headed households; and that 34 percent of the agricultural labor productivity gap is explained by spillovers from labor market gender differences and 30 percent is explained by gender differences in the use of purchased inputs. Chapter 2 provides a decomposition analysis of the observed reductions in sulfur dioxide, nitrogen dioxide and ozone concentrations, in the twelve richest European countries. It quantifies the proportion of the reductions that can be attributed to fiscal policies, trade, and energy taxes. We find that increasing the share of fiscal spending in GDP and shifting the emphasis towards spending in public goods and against non-social subsidies significantly lower the concentrations of sulfur dioxide and ozone but not nitrogen dioxide. At the same time, energy taxes reduce nitrogen dioxide concentrations but have no effect on ozone and sulfur dioxide. Finally trade openness has a direct effect on sulfur dioxide but no effect on nitrogen dioxide or ozone. Our estimates account for time-varying unobserved heterogeneity. Chapter 3 is the first paper that uses the nationally representative Malawi 2009/2010 dataset. Its purpose is the initial statistical verification of the obtained data and provides a first assessment of agricultural productivity and gender in Malawi. We find that while female-managed plots are, on average, 25 percent less productive, 82 percent of this mean differential is explained by differences in inputs, assets and household characteristics, mainly due to high-value crop cultivation and household adult male labor inputs.Item DEVELOPMENT, VALIDATION, AND APPLICATION OF A QUANTITATIVE POLYMERASE CHAIN REACTION ASSAY TO ASSESS HEMATODINIUM PEREZI PREVALENCE IN ENVIRONMENTAL SAMPLES(2012) Hanif, Ammar; Schott, Eric J; Jagus, Rosemary; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Dinoflagellate parasites in the Hematodinium genus have emerged as important pathogens of economically important crustaceans worldwide, causing significant economic losses to fisheries and aquaculture. An understanding of the routes of infection in blue crab (Callinectes sapidus) populations would be facilitated by an improved knowledge of environmental reservoirs. A previously used PCR assay, based on small subunit rRNA sequences, lacked the specificity needed for Hematodinium perezi detection of environmental samples. Therefore a quantitative PCR assay based on the internal transcribed spacer 2 (ITS2) region of H. perezi rRNA genes was developed, validated, and applied to examine temporal and spatial incidences of environmental reservoirs in Delmarva coastal bays. H. perezi was detected in sediment and water in several Delmarva coastal bays, as well as the host, C. sapidus. Results suggest the existence of localized sediment reservoirs in areas where hydrological and geophysical features allow for the formation of cell deposits.Item Sustaining Peace? Environmental and Natural Resource Governance in Liberia and Sierra Leone(2011) Beevers, Michael David; Conca, Ken; Government and Politics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Over the last decade environmental and natural resources governance has received a growing share of attention on the international peacebuilding agenda. Few studies have scrutinized in detail the role of international peacebuilders or whether reforms and policies help or hinder peacebuilding outcomes. This dissertation examines international efforts to shape the governance of forests in Liberia and diamonds and minerals in Sierra Leone. I find that international peacebuilding organizations frame the challenge in both cases as transforming conflict resources into peace resources for the purpose of reducing the propensity for violence. To accomplish this transformation, international peacebuilders promote and establish governance reforms and policies designed to securitize and marketize the environment and natural resources. I find that, despite producing the potential peace enhancing benefits of increased stability and revenue, rapidly pushing such a transformation strategy comes with significant linked pathologies that run the risk of recreating pre-war political arrangements, provoking societal competition, undermining environmental management and sustainable livelihoods, and creating unrealistic expectations. These effects can produce contention, foster resistance and increase the likelihood of violence in ways that undermine the conditions essential for achieving a long-term peace. An alternative approach would be to mitigate the effects of securitization and marketization by first addressing issues that have historically led to violence and contention in the environmental and natural resources sector, including land ownership and tenure issues, genuine public participation, government corruption and a lack of sustainable livelihoods.Item Cross-Sectional Evaluation of Potential Volatile Organic Compound Exposures Around U.S. Schools(2009) Perodin, Joanne; Sapkota, Amir; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Volatile Organic Compounds (VOCs), characterized by high vapor pressure and low water solubility, exist in gaseous phase at room temperature. Previous studies have suggested exposure to VOCs may be associated with adverse health effects such as asthma exacerbation and in some cases cancer. The major sources of outdoor VOCs include traffic and industrial emissions. Ambient VOCs can react with Nitrogen Oxides (NOx) in the presence of sunlight to form ground level ozone, one of the U.S. Environmental Protection Agency (EPA) Criteria Air Pollutants. This thesis was designed to investigate the potential VOCs exposure among U.S. schoolchildren. Moreover, the influence of various neighborhood factors (urban vs. rural areas, distance from highways, presence/absence of industries) on VOCs concentrations around U.S. Schools was investigated. The findings of this thesis suggest that schools in urban areas, near industries and traffic activity have higher concentrations of VOCs compared to those not possessing such characteristics.Item Environmental influences on physical activity and obesity in African American adolescents-a multilevel perspective(2009) Yan, Fang Alice; Beck, Kenneth; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: Prevalence of obesity among adolescents is increasing at an alarming rate. Currently, 34% of all 12-19 year olds are either at risk for overweight or are overweight. Without a comprehensive understanding of the myriad of environmental factors that influence physical activity, we cannot effectively curb the rising rates. Methods: The objective of this study is to evaluate the direct and indirect effects of individual, built, and psychosocial environmental factors on the body mass index (BMI) of African American adolescents, and to assess how the relationships may be mediated by physical activity (PA) levels in an urban setting. A cross-sectional sample of 350 Students (grades 9-12) was drawn from two urban magnet high schools in Baltimore City. The outcome measurements cover a broad array of variables, including BMI, walking behavior, and overall PA. The independent variables are measures of three environments and individual socio-demographic status. The hierarchical linear model analysis was employed. In addition, the mediation analysis was conducted to examine the mediating effect of PA levels. Results: The majority of the sample was African American (69%) and female (58%) with 40% at risk of overweight or overweight. After adjustment for individual socio-demographic factors, living in more hazardous neighborhoods was positively associated with moderate-to-vigorous physical activity (MVPA) and walking for transportation but not with BMI. Densities and proximities of destinations were not associated with BMI. Access to school and museums within 0.25 mile, and grocery stores, retail and shopping, post offices and mix of destinations within 0.5 mile and beyond was positively associated with participation in walking. In addition, densities of fast food restaurants, parks and recreation within 1 mile and 1.5 mile were associated with increased walking. Closer proximity to schools and museums increased both student's MVPA level and their walking trips. Green space coverage within 0.25 mile distance was associated with decreased BMI. In addition, the percentage of green space coverage around homes was not associated with physical activity. Physical activity did not mediate either the destination densities and proximity or the greenness on BMI. Conclusion: The findings support the importance of focusing on places rather than the individuals who live in those places. Increasing the diversity of walkable destinations may contribute to adolescents doing more transport-related walking and achieving recommended levels of physical activity. In general, ecologic approaches to obesity prevention need to focus on urban design and food availability.Item Environmental Opportunities in Conceptual Design: Enhancing the TRIZ Database with ENERGY STAR Products and Functional Models(2007-06-22) Morgan, David; Schmidt, Linda; Mechanical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Engineers use the product design process is to create new products. This process begins with a problem statement and conceptual design and concludes with the embodiment design phase, where the details of the product are formed and final designs are created. There are efforts being made to increase awareness of the impact of the decisions made in this process with respect to the environment. Currently, environmental design is done in the embodiment phase, far into the design process and after a concept is selected. This paper focuses on a method to consider environmental design during concept generation. This research will show how environmental products can be incorporated into the TRIZ database (in English, TIPS - Theory of Inventive Problem Solving). TRIZ is an organized and advanced form of design by analogy and is based on overcoming contradictions between a set of engineering parameters. TRIZ provides innovative principles that are linked to a repository of patents and products. The fundamental research question for the basis of this work is: Can the TRIZ method be expanded for the design team that places high value on environmentally benign designs? This can be broken down into more specific questions. Question One: How do you find products to expand the TRIZ database specifically so that it can be more useful for environmentally benign design changes? Question Two: How can function structures be used to catalog environmental innovations and aid in applying TRIZ principles? This work will demonstrate how this expansion of TRIZ can be accomplished and will yield three unique contributions. There are three contributions to this work. Contribution One is the analysis of the relative frequency of TRIZ principles for combinations of engineering characteristics within the TRIZ contradiction matrix. Contribution Two is the use of function models, according to the function basis to characterize technical performance contradictions in terms of TRIZ engineering characteristics and to identify environmental innovations in existing designs. Contribution Three is providing support for the validity of expanding the TRIZ database using certified green products and functional modeling. This will be demonstrated by examining electrical energy saving household appliances, and detailing the process by which they can be added to the TRIZ database.