Integrated Experimental and Software Methods for Non-Targeted Analyses Investigation of Vehicle-Derived Chemicals and Their Transformation Products

Hu, Ximin ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Water pollution is a significant environmental issue that can yield detrimental impacts on human health and ecosystem. Compounding the basic environmental pollution problem is the fact that many chemicals can undergo various transformation reactions under environmental conditions to form structurally similar transformation products (TPs). Notably, some TPs may contribute significantly to the potential for adverse effects in environmental systems while their characteristics and transformations are not fully understood. For example, among various pollutant classes, vehicle-derived chemicals and their TPs are a growing concern, representing compounds that are concurrently abundant (by mass use), widespread, and poorly characterized or identified. For instance, our group recently identified 6PPD (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine), a ubiquitously used tire rubber antioxidant, would be transformed under environmental conditions into 6PPDQ, a toxicant which is responsible for the coho salmon (Oncorhynchus kisutch) acute mortality observed for several decades in the Pacific Northwest. Therefore, there is a pressing need to chemically characterize and to investigate the environmental fate and transport of these classes of vehicle-derived chemicals and their TPs for comprehensive environmental risk assessment, remediation and policy making.Problematically, identifying and tracking specific groups of pollutants or contaminant sources is often challenging due to the complex chemical matrices present in surface waters and the relatively narrow detection capabilities of traditional analytical methods (e.g., targeted analytical methods via low-resolution mass spectrometry) that focus on limited numbers of pre-defined analytes. Non-targeted analysis (NTA) can potentially address this challenge by coupling high-resolution mass spectrometry (HRMS) instrumentation with data science approaches for data analysis to better identify or quantify unknown pollutants or contamination sources in complex mixtures. However, the development of HRMS data processing workflows is still in a relatively early stage, is often labor intensive, and can lack well-established protocols and integrated data processing capabilities, especially for open-source software, for environmental data and systems.To address the challenges above, this thesis communicates the development of improved integrated experimental and open-source software methods for NTA using HRMS instrumentation and capabilities. Subsequently, these methodologies were deployed for the chemical characterization of vehicle-derived chemicals, focusing on the industrial antiozonant 6PPD widely used in tire rubbers and related transformation products. Chapter 1 presents an introduction to these systems. Chapters 2-4 communicate the analysis and characterization of 6PPD and related TPs. 6PPD TPs include 6PPD-quinone (6PPDQ), which is an emerging contaminant that was previously identified as the "primary causal toxicant" for acute mortality events in stormwater-exposed coho salmon. Given its extraordinarily high toxicity, interest in 6PPDQ properties and fate extends from local to global scales. Experiments were conducted to (a) investigate the physiochemical properties of 6PPDQ; (b) measure 6PPD ozonation dynamics and quantify known TPs (i.e., 6PPDQ); (c) prioritize other potential 6PPD TPs with HRMS-based NTA; and (d) evaluate the environmental fate of 6PPD and formation of TPs under varied environmental conditions (ozone exposure, aerobic and anaerobic conditions) while quantifying 6PPD and TPs with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chapters 5-6 focus on method development for HRMS NTA, including workflow development for NTA data processing and development and optimization of source identification and apportionment methodologies.Chapter 1 provides an introduction and explains the research goals of the thesis. Chapter 2 discusses the investigation of the physiochemical properties of 6PPDQ, including logKow, solubility, leaching potentials, sorption potentials and aqueous stability. We focused on reporting chemical characteristics relevant to the fate and transport of the recently discovered environmental toxicant 6PPDQ. The aqueous solubility and octanol-water partitioning coefficient (logKow) for 6PPDQ were measured as 38 ± 10 μg L−1 and 4.30 ± 0.02, respectively. Within the context of analytical measurement and laboratory processing, sorption to various laboratory materials was evaluated, indicating that glass was largely inert but loss of 6PPDQ (including non-recoverable mass) to other material types was common, including materials commonly found in the laboratory. Aqueous leaching simulations from tire tread wear particles (TWPs) indicated short-term release of ∼5.2 μg 6PPDQ per gram TWP over 6 h under flow-through conditions. Aqueous stability tests observed a slight-to-moderate loss of 6PPDQ over 47 days (26 ± 3% loss) for pH 5, 7, and 9. These measured physicochemical properties suggest that 6PPDQ is generally poorly soluble (almost surprisingly so) but fairly stable over short time periods (~5% loss over 3d) in simple aqueous systems. 6PPDQ can also leach readily from TWPs for subsequent environmental transport, posing high potential for adverse effects in local aquatic environments.Chapter 3 evaluated the transformation kinetics of 6PPD degradation and 6PPDQ formation using heterogeneous 6PPD ozonation in the gas phase. We investigated TP formation occurring during heterogeneous reaction of gas-phase ozone with 6PPD; exposures included both pure 6PPD solids and TWP rubber. (Abstract shortened by ProQuest).

Wondering With People, Places, and More-Than-Humans as an Ontological Orientation to Ethical Socio-Ecological Education: Towards More Just & Livable Futures Through Design-Based, Mediational, and Quantitative Analyses

Sherry-Wagner, Jordan D ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This dissertation is aimed at articulating and empirically characterizing an expansive orientation to field-based socio-ecological systems learning that elevates participatory and ethically-engaged approaches to teaching and learning. Grounded in relational ways of knowing, this dissertation works to expand and transform normative educational paradigms towards the realization of more just and healthful ways of being through recognizing the agency and dignity of youth, places, and more-than-human beings. Elevating the role of wonder as central to scientific sensemaking, ethical deliberation, and the creation of new forms life and learning, this dissertation contributes to scholarship, practices, and the construction of life-worlds critically engaged with the increasingly pressing challenges and possibilities of the 21st century. Situated within a space of problem and possibilities, this dissertation addressed the need to shift nature-culture relations through analysis of design and interactions situated in the Learning in Places project. Across five chapters I situate and develop three related papers which characterize and empirically ground a framework for ethical wondering with people, places, and more-than-humans. The first chapter situates this work in transdisciplinary approaches to science education and begins to construct a framework for how we have taken up the role of wondering in our context of work. The three following chapters represent the primary papers in this dissertation. In Chapter 2, I analyze materials designed in the Learning in Places project to explicate key dimensions and commitments of our work and build out an empirically-grounded conceptual framework for ethical wondering with people, places, and more-than-humans. In Chapter 3 I conduct a deep case study analysis of knowledge and interaction to examine how dimensions of ethical wondering with people, places, and more-than-humans were manifest and mediated within wondering walk data gathered from the pilot year of Learning in Places implementation. Complimenting this deep qualitative focus, Chapter 4 shares findings from a broad statistical analysis of over 98 hours of wondering walk data collected in our first full year of school-based storyline implementation to identify significant correlations and comparisons between descriptors of interest. By way of synthesis and conclusion, Chapter 5 closes out this dissertation through offering up principles of design to guide work in similar spaces alongside reflections salient strengths, limitations, and pathways for future work.

Antiblackness and Fundamental Accumulation: An Aesthetic Ontology of Prohibition and Persistence Through Black Arts

Burns, Gust Henry ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This dissertation elaborates an answer to the question, what is antiblackness? Countering understandings of antiblackness as a fundamentally psychic force, the dissertation develops the concept of fundamental accumulation as the antiblack prohibition of aesthetic capacity, a process that is both material and immanent. Antiblackness, as this prohibition of temporal, spatial, and motile capacity to blackness, is read alongside modes of black refusal and antagonism, through five black artistic works from the past fifty years. Chapter 2 examines the antiblack prohibition of temporal capacity, and its refusal as black persistence, through a reading of Sarah Maldoror's 1972 film Sambizanga. Chapter 3 examines the antiblack prohibition of spatial capacity, alongside black antaesthetics, through a reading of Dionne Brand's books A Map to the Door of No Return: Notes to Belonging (2001) and Ossuaries (2010). Chapter 4 analyzes the We Still Outside Collective's 2020 video On the black leadership and other white myths, and Kahlil Joesph's 2013 short film Until the quiet comes, in order to theorize black motion as an immanently antagonistic movement. The dissertation's introduction provides a genealogy of afropessimism, outlining and critiquing Frank Wilderson's structuralist analysis of antiblackness as proper to the symbolic register, and posits the need for a materialist account of antiblackness. Chapter 1 develops the concept of antiblackness as fundamental accumulation via comparison with primitive accumulation as theorized by Marxist thinkers, and a close reading of Marx's own understanding of slavery as integral to the development of capacity, community, and the self, in a passage from the Grundrisse. The first chapter also outlines the dissertation's methodology of aesthetic ontology, placing the dissertation's arguments and stakes within the context of contemporary criticism and analysis of black artistic works and practices.

“I Was Part of This Whole New Movement”: A Narrative Study of the Drakensberg Boys’ Choir and Its Role in Nation-Building at the End of Apartheid in South Africa

Lombard, Marshell Clive ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

This study investigates whether the Drakensberg Boys’ Choir played a role in nation-building in South Africa towards the end of and post-apartheid. The investigation included consulting the literature on the topic and three interviews with Drakensberg Boys Choir alums who were members of the school (and choir) during this time in South Africa. A brief overview of the history of South African music during apartheid is given for context. The narrative research design was chosen for this dissertation so that interviewees could tell their stories and have them presented as authentically as possible, in consideration of the sensitivity of the topic. Reviewing the narrative research design process (as advised by Creswell (2005:480), the interviews were restoryed to help the reader make sense of the information collected. Themes were created from these restoryed interviews to allow for a deeper understanding of the interviewees' experiences. The findings of this study are presented in the conclusion of this dissertation.

Ozone Stratosphere-Troposphere Exchange in the Past, Present, and Future

Wang, Mingcheng ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

As a key component of the Earth system, stratospheric ozone protects life on Earth from hazardous ultraviolet radiation and has a crucial impact on tropospheric chemistry. Stratosphere-troposphere exchange (STE) of ozone represents a significant source term in the tropospheric ozone budget and can impact surface ozone concentrations, tropospheric oxidation capacity, and methane lifetime. The stratospheric ozone and ozone STE in the past, present, and future climates are investigated in this dissertation.In Chapter 2, we estimate the STEs of air masses and ozone concentrations averaged over 2007 to 2010 using the Modern Era Retrospective analysis for Research and Application, version 2 (MERRA2) and ERA5 reanalyses, and observations. The extratropical downward ozone fluxes are 528-543 Tg year-1 from these reanalyses and observations, consistent with previous studies. Previous studies, however, did not consider tropical upward ozone flux. Here we show that the tropical upward ozone flux is 185 Tg year-1, compensating about 35% of the extratropical downward ozone fluxes, and should not be neglected. After considering the tropical upward ozone flux, the global ozone STE is 347±12 Tg year-1, which can be used as the contribution of ozone STE to the tropospheric ozone budget. Cloud radiative effects on the STE of air mass and ozone are also investigated. At 380 K, cloud radiative effects enhance downward fluxes in the extratropics from both reanalyses and observation, but reduce and enhance upward fluxes in the tropics from reanalyses and observation, respectively. The discrepancy in the tropics is related to the tropical tropopause layer thin cirrus that is missing in the reanalyses. It is found the cloud radiative effects enhance the global ozone STE by about 25%.In Chapter 3, STE of air mass and ozone in ERA5 and MERRA2 reanalyses from 1980-2022 are investigated. We employ a lowermost stratosphere mass budget approach with dynamic isentropic surfaces fitted to tropical tropopause as the upper boundary of lowermost stratosphere. The seasonal cycle, annual-mean climatology, and monthly anomalies of air mass and ozone STEs are studied. The annual-mean ozone STEs over the NH extratropics, SH extratropics, tropics, extratropics, and globe in ERA5 are -342, -239, 201, -581, and -380 Tg year-1, respectively, versus -305, -224, 168, -529, -361 Tg year-1 from MERRA2. The annual-mean global ozone STE difference between ERA5 and MERRA2 is dominated by diabatic heating difference, partly compensated by ozone concentration difference. There are about 40% (-40%) differences between ERA5 and MERRA2 in global ozone STEs in boreal summer (autumn), mainly due to the difference in seasonal breathing of the lowermost stratosphere ozone mass between reanalyses. For the global ozone STE monthly anomalies, ERA5 and MERRA2 can only explain each other's variance by 30%. Multiple linear regression analysis shows that El Nino-Southern Oscillation, Quasi-Biennial Oscillation, Brewer-Dobson circulation (BDC), solar cycle, and volcanic aerosols can only explain the variance in global ozone STE monthly anomalies by 0.9-1.8, 2.5-3.9, 0.1-1.0, 0.2-0.3, 1.7-4.1%, respectively, with a residual variance larger than 90%. Furthermore, the volcanic aerosol impacts on ozone STEs from ERA5 and MERRA2 have opposite signs and thus are inconclusive. Cautions are therefore needed when using ERA5 and MERRA2 to investigate the STE seasonal cycle and interannual variability.Chapter 4 investigates the changes in the stratospheric ozone in the Last Glacial Maximum (LGM) as compared with preindustrial (PI) climate, using the Whole Atmosphere Community Climate Model 6 (WACCM6). It is shown that, compared with PI times, LGM modeled stratospheric temperatures are increased by up to 8 K, leading to faster ozone destruction rates for gas phase reactions, especially via the Chapman mechanism. On the other hand, stratospheric hydroxyl radical (OH) and nitrogen oxides (NOx) concentrations are decreased by 10-20%, which decreases catalytic ozone destruction, thereby decreasing ozone loss rates. The net effect of these two compensating mechanisms in the upper stratosphere (above 15 hPa) is a vertically-integrated 1-3 Dobson Unit (DU) decrease during the LGM. In the lower stratosphere (tropopause to 15 hPa), changes in the stratospheric overturning circulation and resulting transport dominate changes in ozone. Consistent with a weakening of the residual circulation in the LGM, lower stratospheric ozone is increased by 2-5 DU in the tropics and decreased by 5-10 DU in the extratropics, but the latter is partly compensated by ozone increases due to a lower tropopause. It is found that tropospheric ozone is decreased by about 5 DU in the LGM versus PI. Combined changes in stratospheric and tropospheric ozone lead to a decrease in total ozone column everywhere except over the northeast North America, equatorial Indian and west Pacific Oceans, and East Antarctica. Surface ultraviolet radiation in the LGM versus PI is increased over the Northern Hemisphere mid- and high-latitudes, especially over the ice caps, and over the Southern Hemisphere near 60° S.In Chapter 5, changes in the air mass and ozone STEs in the Last Glacial Maximum (LGM) as compared with preindustrial (PI) climate are studied using WACCM6. We use dynamic isentropic surfaces that are determined by fitting to the tropical tropopauses as the upper boundary of the lowermost stratosphere in a mass budget approach, a method particularly suitable for estimating air mass and ozone STEs across different climates. Relative to the PI, the magnitude of ozone STE in the LGM is decreased by 14-19%, 18-24%, 18-23%, 16-21%, 15-21% over the NH extratropics, SH extratropics, the tropics, the extratropics, and the globe, respectively. The extratropical and global decreases are mainly caused by decreased ozone in the extratropical lower stratosphere associated with a weakening of BDC, while changes in air mass fluxes play a minor role because the effects of weakening BDC and increased isentropic density partly cancel each other. Analysis of the modelled tropospheric ozone budget indicates that the ozone STE in the LGM is 28% of the tropospheric ozone production rate, as compared to about 9% in the modern climate (year 2000) and 19% in the PI.In Chapter 6, we investigate changes in STE of air masses and ozone concentrations from 1960 to 2099 using multiple model simulations from the Chemistry Climate Model Initiative (CCMI) under the climate change scenario RCP6.0. We employ a lowermost stratosphere mass budget approach with dynamic isentropic surfaces fitted to the tropical tropopause as the upper boundary of lowermost stratosphere. The multi-model mean (MMM) trends of air mass STEs are all small over all regions, which are within 0.3 (0.1) % decade-1 for 1960-2000 (2000-2099). The MMM trends of ozone STE for 1960-2000 are 0.3, -2.7, 3.4, -0.9, and -2.7% decade-1 over the NH extratropics, SH extratropics, tropics, extratropics, and globe, respectively. The corresponding ozone STE trends for 2000-2099 are 3.0, 4.3, 0.8, 3.5, and 4.7% decade-1. Changes in ozone STEs are dominated by ozone concentration changes, driven by climate-induced changes and ozone-depleting substance (ODS) changes. For 1960-2000, small changes in ozone STEs in the NH extratropics are due to a cancellation between effects of climate-induced changes and ODS increases, while the ODS effect dominates in the SH extratropics, leading to a large ozone STE magnitude decrease. Increased ozone transport from tropical troposphere to stratosphere for 1960-2000 is due to increased tropospheric ozone. A decreased global ozone STE magnitude for 1960-2000 was largely caused by ODS-induced ozone loss that is partly compensated by climate-induced ozone changes. For 2000-2099, about two-thirds of global ozone STE magnitude increases are caused by ozone increases in the extratropical lower stratosphere due to climate-induced changes. The remaining one-third is caused by ozone recovery due to the phaseout of ODS.

Empirical Approaches to the Near-Infrared Tip of the Red Giant Branch

Durbin, Meredith ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The infrared tip of the red giant branch (IR-TRGB) is a powerful tool for measuring distances to galaxies in the local Universe. However, establishing its absolute "anchor" with sufficient precision and accuracy has proved challenging due to lingering sources of systematic uncertainty in both theoretical predictions and empirical calibrations. Here I describe three studies aimed at improving observational constraints on the IR-TRGB. First, I develop a computational method for self-consistently measuring TRGB magnitudes and colors, and the covariance thereof, in multiwavelength stellar photometry catalogs. Traditional detection methods either marginalize over color, or else rely on assuming a fidicial color dependence, both of which may result in different stellar populations dominating the TRGB signal at different wavelengths. Next, I explore two complementary approaches to reconciling observations of the IR-TRGB as measured with ground- and space-based instruments respectively. The former are impacted by absorption features in Earth's atmosphere, where the latter are not. Furthermore, there is an extremely limited range of magnitudes at which current facilities can achieve the requisite data quality from both locations. To this end, I derive transformation equations between respective photometric systems using synthetic photometry of observed stellar spectra, and then present initial results from a three-year observing campaign designed to directly compare space- and ground-based observations of bright RGB stars in the Magellanic Clouds.

Using Machine Learning to Identify Functional Properties of Complex Systems: From Neurons to Networks

Zdeblick, Daniel ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

The human brain may be the most complicated thing in the discovered universe. Now is an exciting time, when the capabilities of computing and neural recording technologies provide unprecedented opportunity to use advanced machine learning models to begin understanding it. The two main goals of such models are to successfully predict neural data withheld from training and to provide scientific insight into the functioning of the neural system. To this end, I introduce two model designs, each of which achieves these goals by incorporating a scientific hypothesis about the brain into the structure of the model. First, in Chapter 2, I train models of individual neurons with the assumption that these models are well described by a finite number of cell-types. A hierarchical model that uses the expectation-maximization algorithm to simultaneously learn parameters associated with individual neurons and a description of the cell-types allows parameters associated with each neuron to borrow strength from other neurons’ data. I use simulated data to show that this allows the hierarchical model to recover true model parameters and cell type identities better than single-cell models that make no assumption about cell types and are clustered after being fit independently. I apply this hierarchical model to recordings from 634 neurons and show that, compared to the naive approach described above, it yields better predictions of held out data for the overwhelming majority of neurons and discovers cell types that are more robust to the exclusion of different neurons from the training data. These discovered cell types also relate to available information about the gene-expression, morphology, and location of each neuron.Then, in Chapter 3, I “joint-train” neural networks to simultaneously predict the activity of a neural population and perform an auxiliary task, hypothesized to be related the the function of those neurons. I find analytic conditions for when the inclusion of an auxiliary task can improve prediction of neural responses in a linear network, and derive an expression for the degree of improvement, which reveals that the most useful auxiliary tasks are those most predictable from the neural data. I then show that this result is born out in deep, nonlinear, structured networks via numerical analyses with simulated data. These analyses also reveal that joint-training allows the model to precisely and accurately associate simulated neurons with a subset of model units. Finally, I use further theory and numerical analysis with the linear model to show how a derived condition on network structure necessary for an auxiliary task to yield improved neural response prediction is modified by nonlinearities, constraints on network parameters, and finite training time, providing insight into how the numerical results differ from those predicted by our theory.Overall, this work provides insights into how we might incorporate specific hypotheses about brains into statistical models in order to best explain neural data and gain insight into the functioning of neural systems.

Priority Setting for Achieving Universal Health Coverage in Nigeria: A Spatial and Temporal Analysis and Cost-Benefit Analysis

Kawakatsu, Yoshito ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Universal Health Coverage (UHC) is an urgent global priority outlined in the Sustainable Development Goals (SDGs) to ensure the accessibility of health services for all people without causing financial hardship. If current progress continues to 2030, 37% to 61% of the global population will not be covered by essential health services. Therefore, we need to accelerate the increase of service coverage to achieve the UHC target by 2030.There are three specific aims of this dissertation; 1) To identify both individual and contextual factors that are consistently associated with utilization of nine essential maternal and child health services (i.e., ANC, facility-based delivery, modern contraceptive use, immunizations, and childhood illnesses), across survey years and household geolocations, using five national representative cross-sectional surveys in Nigeria; 2) To estimate grid-level coverage of selected essential MCH services in Nigeria using generalized additive models (GAMs) and Gradient Boosting (GB) 3) To estimate required costs and avoidable child deaths by increasing selected essential health service coverage in each community, and to identify the priority sub-national areas.This dissertation emphasizes the importance of multi-dimensional priority setting in achieving Universal Health Coverage in Nigeria. By identifying the factors influencing health service utilization, assessing regional disparities, estimating required costs, and quantifying potential impacts, policymakers can make evidence-based decisions to maximize the efficiency and effectiveness of healthcare interventions. The findings and recommendations of this research contribute to the broader global agenda of achieving UHC and improving health outcomes for all populations, particularly in low- and middle-income countries.

Religion in Contentious Times: Climate Change, Abortion Rights, and War

Mrchkovska, Nela ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

Religion remains a potent force in our modern society, influencing people's lives and guiding their answers to existential questions in an ever-evolving world. The enduring nature of religion lies in its ability to be shaped by, as much as it shapes, the society it inhabits. This dissertation presents three empirical studies highlighting the role of religion, both from an institutional and individual perspective, in addressing three pressing contemporary issues: climate change, abortion rights, and war. The findings illustrate the adaptability and fluidity of religion in response to local contexts and current events.The first two papers provide a systematic study of how religious leaders, as "street-level bureaucrats" of religious institutions, craft sermons based on the demographic, sociological, and geographical factors of their communities, as well as concurrent events. What clergy choose to address in their sermons is not random. Instead, sermon topics are a product of their authors' beliefs, perceptions of their congregations' needs, and central norms and rules. Both papers use an original and unique dataset of 220,000 weekly sermons collected from 3,000 congregations across the United States. The content of the sermons provides insight into how, where, and when clergy engage politically- and socially-charged topics such as climate change and abortion rights. In a religiously pluralistic society, where individuals can choose where to seek spiritual guidance, the messages they hear during their weekly meetings are arguably a large determinant in what shapes their choice of congregation. Thus, choosing topics to include in weekly sermons are of great strategic importance to clergy.The first paper "Hear Ye, Hear Ye: When and Where Religious Leaders Preach on Climate Change" explores this process by studying how congregations address the contentious issue of climate change in their weekly meetings. As climate change and its consequences are increasingly framed as a moral issue, the religious interpretation of the human connection to the environment has varied tremendously across religious bodies as has the frequency with which clergy engage with this topic. Using text analysis tools, a dictionary-based approach and text classification with Large Language Models (LLMs), I find that both demographic characteristics of the congregations' surrounding neighborhood and environmental factors help explain this variation. Across different models and subsets, the political ideology of the local neighborhood is a persistent factor in how frequently climate-related discourse appears in weekly sermons. Evidence from these analyses also shows that the level of income and the racial composition of the neighborhood, as well as the level of air pollution in the surrounding area of a given congregation, are also strong determinants of climate change discourse in congregations. Thus, the findings suggest that the salience of an issue in a given local context drive how clergy perceive the needs and wants of their communities and address their congregations accordingly, which highlights religion's ability to cater to its flocks.The second paper titled "Holy Words, Contentious Topic: Analysis of Political Speech on Abortion Rights in Religious Sermons" tracks the same process on another contentious issue -- abortion rights. This paper also engages with the perceived wants and needs of the local neighborhood and exogenous factors related to abortion rights, but it includes an additional set of determinants. Specifically, it includes the hierarchy of a given congregation based on its denomination (centralized versus decentralized) and the size of the supportive network of the congregation (number of congregations from the same denomination that are relatively close in space to one another). These two additional factors account for clergy's incentives and resourcefulness and connection of congregations in engaging with contentious topics. Utilizing difference-in-difference study design and leveraging the US Supreme Court's decision in Dobbs v. Jackson Women's Health Organization, I find that in states where the decision had considerable socio-legal implications for communities, congregations address abortion more, but they only do so in communities where the denominational position on abortion rights aligns with the perceived ideological position of the congregation's surrounding neighborhood. This effect is amplified if the congregation is embedded within a supportive network and when clergy are dependent on the local community rather than centralized religious bodies in securing their positions. The findings in this paper align with the findings from the first one in that, in both cases, the frequency of the topics of interest was driven largely by the local context.In the third paper of this dissertation "The (Not So) Sacred Image of Russia: Survey Experiment on Popular Support of Ukraine in the Russia-Ukraine War", I shift from a focus on sermons and the clergy's role in shaping and/or adapting to congregant perceptions to explore religion's role as a source of long-term identity and how that identity may manifest itself in forming opinion of contemporary events. One's religious identity is formed through a process of socialization that involves larger social (religious) groups influencing underlying values, preferences, and behavior. To what extent this identity formation affects the reaction to important political and social events is a topic of interest to scholars. I address this topic with a survey experiment in the context of the contentious Russia-Ukraine war, specifically within Bulgaria -- a society historically and nationally tied to one major religion, Christian Orthodoxy, and one that has had a complex and involved relationship with Russia. I investigate the significance of affiliating with the Christian Orthodox faith in shaping in-group attitudes when the Russia-Ukraine war is framed as a cultural-religious war with Russia as the Christian Orthodox protector on one side, and Western-backed Ukraine on the other. I find that respondents' attitudes toward the war are not driven by their religious affiliation, nor the intensity of their religious identity, beliefs or behavior, but rather by the level of information they receive regarding the war as well as their fears of being drawn into the war. These findings suggest that concurrent events and information mitigate the extent to which religion can influence preferences and attitudes in a given society.In our modern society, where religion competes with the advances of science and technology, and the forces of secular and rational thought, the socio-political relevance of religion depends on its ability to adapt. As evidence from this dissertation shows, religious institutions are flexible with respect to the needs and desires of their constituencies, but religious identity isn't always salient in all contexts. This indicates the complex nature that religious belief and religious institutions play in human behavior, a topic of inquiry that will continue to intrigue scholars in decades to come. Competing to retain and attract members, religious institutions respond to community demands, prompting individuals to continually seek comfort and guidance from the pews. By doing so, they not only maintain their relevance in individuals' personal realm but also sustain themselves as institutional pillars, even in an age where many see them as obsolete. As a social identifier and embodiment of values and beliefs, religion's power is constrained by our information-rich, globalized world. However, when religion adapts to modern challenges, it showcases its most resilient nature. This dissertation highlights these mechanisms by considering three contentious issues in a comparative context.

In Silico Techniques to Improve Understanding of Gait in Cerebral Palsy

Kuska, Elijah C ProQuest Dissertations & Theses University of Wash 2023 해외박사(DDOD)

소속기관이 구독 중이 아닌 경우 오후 4시부터 익일 오전 9시까지 원문보기가 가능합니다.

In this dissertation we focus on utilizing computer-aided engineering techniques to improve our understanding of gait in cerebral palsy (CP). CP is the most common motor disability in children and arises from a non-progressive brain injury at or near the time of birth which alters control (i.e., poor coordination and increased muscle co-contraction). Additionally, individuals with CP often develop secondary, progressive impairments like weakness and contracture. Current treatments to improve mobility in CP primarily target secondary impairments but functional outcomes are inconsistent, leaving treatment efficacy at around 50%. To improve treatment efficacy, clinicians need a better understanding of the complex interactions between, and relative effects of, multi-modal neuromuscular impairments on gait. However, eliciting interactions between, and relative effects of, neuromuscular impairments on gait is difficult or even impossible to do clinically and experimentally. Thus, the goal of this dissertation was to utilize in silico techniques to improve the understanding of gait in CP. Specifically, we use physics-based (i.e., musculoskeletal) modeling, optimal control (i.e., neuromuscular simulation), and data-driven modeling (i.e., machine learning) to investigate the interactions between, and relative effects of, altered control, muscle weakness, and contracture on gait and predict and understand gait energetics in CP which can be used to improve treatment efficacy. The effects of altered motor control on gait are poorly understood because altered control persists post-intervention and its relative effects are difficult to discern amidst secondary impairments, like weakness and contracture. Prior studies have investigated the impacts of weakness, contracture, and altered control on gait, but they have yet to be investigated together. Thus, in this dissertation we sought to understand the effects of, and interactions between, neuromuscular impairments during gait by utilizing a musculoskeletal model and neuromuscular simulation framework. We simulated nondisabled (ND) gait and then perturbed each simulation with altered control, weakness, and contracture of varying severities. We found that altered control exacerbated the restrictions imposed by secondary impairments: ND gait was less robust to, and required more muscle activation to adapt to, weakness and contracture with altered control when compared to unaltered control (Chapter 3). These findings highlight the inimical effects of altered control on gait and emphasize the advantages of in silico techniques to identify specific impairments, such as altered control, that should take treatment precedence (in silico-informed interventions). However, it is unclear if these conclusions extend to different gait patterns like those in CP. Abnormal gait patterns are common for individuals with CP; the most inimical and common of which is crouch gait. Crouch gait is characterized by excessive knee flexion, which increases knee extensor demand while reducing the knee extensor's ability to extend the knee making it inefficient and disadvantageous. In Chapter 4, we extended our prior computational methods to simulate crouch gait of varying severities. By simulating both crouch and ND gait, and incorporating machine learning (ML), we investigated if the interactions between, and relative effects of, neuromuscular impairments are gait pattern-specific. We determined that the interactions between, and relative effects of, neuromuscular impairments are gait pattern-specific highlighting advantages and disadvantages of walking in crouch. Thus, by combining computational techniques like modeling, simulation, and machine learning we elicited rationale for why individuals may select non-normative gait patterns and emphasized the utility of in silico techniques to parse and identify impairments primarily affecting function in CP which could then be used to inform treatment. Individuals with CP consume on average 2x the energy of their ND peers while walking; the origin of which remains unknown. Elevated energy consumption persists post-intervention making it a primary complaint among patients and objective of research in the CP community. We sought to accurately predict and understand energetics in CP with modeling, simulation, and machine learning to reduce clinical collection burden on patients and caregivers and improve identification of effective treatment methods for reducing energetics in CP. In the final study of this dissertation, we first used our modeling and simulation framework to generate and perturb walking simulations from gait data from the largest database of walking data for individuals with CP. Generated simulations then acted as synthetic data within a machine learning algorithm to complement existing clinical data and attempt to improve predictions of energetics in CP. Using simulations generated for 240 children with cerebral palsy we analyzed the energetic discrepancy-difference between measured and predicted-to identify primary mechanisms elevating energetics in CP (Chapter 5). Synthetic data generated from gait simulations marginally improve prediction accuracy of energetics in CP, but augmented discrepancy models-energetic predictions with the reconstructed discrepancy-improved modeling of CP energetics, identifying kinematics at initial contact and contracture as primary mechanisms elevating walking energy in CP. Utilizing in silico techniques can provide additional synthetic data (i.e., data augmentation) to reduce data collection burdens on patients, caregivers, and clinicians while eliciting additional insight in causal mechanisms affecting gait and function. This dissertation supports in silico informed interventions by improving our understanding of gait in CP. By utilizing modeling, simulation, and machine learning we examined the interactions between, and effects of, neuromuscular impairments on gait in both ND and CP individuals and how that information could better predict and understand energetics in CP. This work provides a foundation to utilize modeling, simulation, and machine learning to rapidly evaluate causal mechanisms impacting gait, probe and parse complex relationships between neuromuscular impairments, and incorporate synthetic data to better inform machine learning algorithms and clinical decision making. In conclusion, the work we have completed over the last 4 years highlights the benefits of in silico techniques to understand gait in CP, seeking to support the creation and implementation of in silico informed interventions for individuals with CP. .