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- Title
- EXPLORING THE REGULATORY MECHANISMS BEHIND CHLOROPLAST POPULATION MORPHOLOGY
- Creator
- Tallerday, Emily Jennings
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Eukaryotic cells tightly regulate their populations of endosymbiotically-derived organelles. Organelle populations can be described in terms of size, number, or coverage, the latter being the collective planar area taken up by the organellar population relative to that of the cell. As the photosynthetic organelle, chloroplasts are vital, and alterations to chloroplast population morphology can affect photosynthetic performance and biomass accumulation. However, how the cell perceives and...
Show moreEukaryotic cells tightly regulate their populations of endosymbiotically-derived organelles. Organelle populations can be described in terms of size, number, or coverage, the latter being the collective planar area taken up by the organellar population relative to that of the cell. As the photosynthetic organelle, chloroplasts are vital, and alterations to chloroplast population morphology can affect photosynthetic performance and biomass accumulation. However, how the cell perceives and regulates its chloroplast population remains a mystery. Division at the mid-plastid (binary fission) is the primary mechanism by which chloroplasts increase their population sizes. It has been well established that lower division rates result in a small population of enlarged chloroplasts, suggesting the existence of a compensatory mechanism ensuring that total chloroplast coverage within the cell is preserved through a tradeoff between chloroplast division and expansion. Most model plants keep a relatively large number of chloroplasts in their leaf cells (>50 per cell). In expanding leaf cells, multiple rounds of chloroplast division typically increase the number of chloroplasts per cell. However, a number of natural adaptive alterations to chloroplast morphology have been observed in several tropical plant species, primarily those native to low-light environments. The tropical plant genus Peperomia (Piperaceae) offers a unique opportunity for understanding the regulation of chloroplast population morphology, as some Peperomia spp. contain two to six giant chloroplasts in their palisade mesophyll cells at maturity, while most others have higher numbers of small chloroplasts in their mesophyll cells. I have characterized chloroplast population morphology in Peperomia, of which six species had not been studied previously, and shown that chloroplast division is inhibited in the palisade cells of Peperomia pellucida. Further, I have assembled and annotated the genome of Peperomia dahlstedtii, the first genome for this genus, and produced a novel transcriptome assembly for P. pellucida. Lastly, I have analyzed gene expression in these two species differing in palisade cell chloroplast population morphology and identified several candidate genes potentially underlying the differences in phenotype. For the first time, I also have described the expression of the chloroplast division genes in these two species. By characterizing variation in chloroplast population morphology in Peperomia, my work builds upon existing research on this trait over leaf development, provides the resources necessary for Peperomia to be used as a model, and identifies potential causes behind the large-chloroplast phenotype documented in several species.
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- Title
- SOCIAL DETERMINANTS OF BREASTFEEDING : THE ROLE OF PRENATAL FOOD INSECURITY
- Creator
- Robinson, Chelsea
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Background: Relatively little work has quantified associations between prenatal food insecurity and breastfeeding practices; however, understanding the implications of prenatal food insecurity may support food insecurity screening recommendations during prenatal care. Therefore, the purpose of this study was to investigate associations between prenatal food insecurity and breastfeeding initiation and duration until 3 months postpartum. Method: This study utilized data from a prospective...
Show moreBackground: Relatively little work has quantified associations between prenatal food insecurity and breastfeeding practices; however, understanding the implications of prenatal food insecurity may support food insecurity screening recommendations during prenatal care. Therefore, the purpose of this study was to investigate associations between prenatal food insecurity and breastfeeding initiation and duration until 3 months postpartum. Method: This study utilized data from a prospective Michigan pregnancy cohort. Women were recruited during their first prenatal visit with planned follow-up through early childhood. Prenatal food insecurity was assessed during pregnancy, and breastfeeding initiation and duration were assessed at the 3-month postpartum visit. Multiple logistic regression models were used to evaluate associations between prenatal food insecurity and the two primary outcomes: breastfeeding initiation and breastfeeding status at 3-months postpartum. Cox proportional hazard ratios were used to assess differences in the risk of breastfeeding cessation until 3 months postpartum by food insecurity status. An adversity index was created to stratify women into higher- and lower-risk groups for not breastfeeding. Associations between food insecurity and breastfeeding at 3 months postpartum (yes/no) were assessed via Fisher’s Exact test within each group. Results: In the unadjusted models, women who reported food insecurity during pregnancy were less likely to initiate breastfeeding (OR = 0.39; 95% CI: 0.21-0.69) and continue breastfeeding until 3 months postpartum (OR = 0.35; 95% CI: 0.20-0.61) compared to food secure women, but the associations were no longer significant after adjustment for sociodemographic and health-related factors. Prenatal food insecurity was not associated with breastfeeding at 3 months postpartum in analyses stratified into high- and low-adversity groups. Conclusions: Prenatal food insecurity is a strong predictor of breastfeeding practices. Though not significantly associated with breastfeeding practices after adjustment, screening for prenatal food insecurity may help clinicians identify women who may need more supports to initiate and maintain breastfeeding.
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- Title
- MIGRANT FARM WORK, COLLEGE, AND MONEY : A PARTICIPATORY ACTION RESEARCH STUDY WITH MIGRANT FARMWORKING COLLEGE STUDENTS
- Creator
- Flores, Amanda
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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College is the first time students have the opportunity to make independent financial decisions and employ financial practices. Research suggests that students pick up financial knowledge, habits, and practices from family, friends, and their broader community and that these practices can have long-term implications. Migrant farmworking college students are a small subset of college students who come from highly mobile families and whose source of income is dependent on agricultural seasons....
Show moreCollege is the first time students have the opportunity to make independent financial decisions and employ financial practices. Research suggests that students pick up financial knowledge, habits, and practices from family, friends, and their broader community and that these practices can have long-term implications. Migrant farmworking college students are a small subset of college students who come from highly mobile families and whose source of income is dependent on agricultural seasons. The migratory lifestyle influences how migrant farmworking families employ financial practices, which likely shapes how children in migrant farmworking families think about their finances and what kinds of financial practices they use. This study explores how the familial and cultural upbringing of migrant farmworking families influences the financial practices of migrant farmworking college students. Grounded in participatory action research methodology, I draw on funds of knowledge and consejos to elevate familial and cultural influences on the financial practices of 5 migrant farmworking college students. Ultimately, this study seeks to provide recommendations for advisors and other student-facing professionals to help meet the diverse needs of this distinct population of marginalized students.
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- Title
- ENGINEERING STUDIES IN ADVANCED PLA MATERIALS – STEREOCHEMISTRY, STEREOCOMPLEXATION, AND THERMAL RECYCLING OF PLA
- Creator
- Alhaj, Mohammed A.
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Polylactide (PLA) polymers are the world’s foremost 100% biobased resin with both composting and recycling end-of-life options in harmony with Ellen MacArthur Foundation “Circularity Model.” It is commercially manufactured by converting lactic acid to lactide, which is then polymerized to PLA. These molecules present unique and intriguing stereochemistry that dictate manufacturing, performance properties, and processability. However, it is seldom discussed and not well understood in the role...
Show morePolylactide (PLA) polymers are the world’s foremost 100% biobased resin with both composting and recycling end-of-life options in harmony with Ellen MacArthur Foundation “Circularity Model.” It is commercially manufactured by converting lactic acid to lactide, which is then polymerized to PLA. These molecules present unique and intriguing stereochemistry that dictate manufacturing, performance properties, and processability. However, it is seldom discussed and not well understood in the role stereochemistry can play and impact product performance and use. In the current work, we critically review and discuss the stereochemical implications for PLA through studies on different PLA compositions.To-date, it is unclear the origin of D-content present in commercial grade PLA, although it is assumed to originate from D-lactide. In this work, we validate that manufacture of lactide monomer from (L)- lactic acid predominantly results in a mixture of L and meso (DL), not L- and D- lactide. Optical rotation and 1H NMR studies are used to elucidate this stereochemistry. Copolymers of L-lactide and meso-lactide and copolymers of L-lactide and D-lactide are synthesized via bulk polymerization at various compositions. The optical rotation, tacticity, crystallinity, and thermal properties of synthesized copolymers are characterized. The optical rotation of poly(meso-lactide) has also been reported for the first time in this text. Differential scanning calorimetry (DSC) and 1H NMR studies confirm that PLA transitions from a predominantly isotactic, semi-crystalline polymer to a predominantly atactic, amorphous polymer when one copolymerizes greater than 10% meso-lactide with L-lactide. The stereochemical composition, mechanical and rheological properties of commercial grade PLA are measured to elucidate the effect of stereochemistry on the tensile and rheological behavior of PLA. We conclude this section with studies on PLA stereochemistry and its influence on immune cellular response. Hydrolytic degradation of semi-crystalline and amorphous PLA is analyzed via molecular weight characterization and lactic acid abundance. Semi-crystalline and amorphous PLA are then studied as potential carriers for glycolytic inhibitors. The stereochemistry of PLA and its implication on performance properties are further explored in studies on stereocomplex PLA. A pilot-scale continuous manufacturing process of stereocomplex PLA is developed and optimized by melt-blending a 1:1 blend of high molecular weight poly(L-lactide) (PLLA) and high molecular weight poly(D-lactide) (PDLA) in a co-rotating twin screw extruder. Stereocomplexation is first characterized via DSC at different temperatures and times. The optimal reaction temperature and reaction time are found and used to process >95% stereocomplex PLA conversion (melting peak temperature Tpm = 240°C). Stereocomplex PLA is used as an additive to produce 70% PLLA/30% stereocomplex PLA composites. The crystallinity, thermal properties, and tensile properties of composites are then characterized. A study on stereocomplex PLA and its effect on the crystallization kinetics of PLLA is conducted. 5% stereocomplex PLA is blended with 95% PLLA to analyze its use as a nucleating agent. The final section discusses a pilot-scale end-of-life method for PLA via thermal recycling. This study continues previous studies on PLA thermodepolymerization by scaling up the reversible reaction in a pilot-scale batch reactor. PLA is run at various temperatures and times to elucidate the processing conditions that yield the highest lactide conversion. The chemical purity, optical purity, lactide yield and stereoisomeric composition of the final lactide product are characterized by DSC, optical rotation, mass balance, and 1H NMR, respectively.
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- Title
- PLANNING FOR AUTONOMY AND ELECTRIFICATION IN FUTURE TRANSPORTATION SYSTEMS
- Creator
- Singh, Harprinderjot
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
-
Autonomous vehicles (AVs) and electric vehicles (EVs) will improve safety, mobility, roadway capacity and provide efficient driving, efficient use of travel time, and reduced emissions. However, these technologies affect vehicle miles traveled (VMT), travel time, ownership cost, and electric grid network. Shared mobility systems can ameliorate the high price of these technologies. However, the shared mobility system poses additional problems such as users’ waiting time, inconvenience, and...
Show moreAutonomous vehicles (AVs) and electric vehicles (EVs) will improve safety, mobility, roadway capacity and provide efficient driving, efficient use of travel time, and reduced emissions. However, these technologies affect vehicle miles traveled (VMT), travel time, ownership cost, and electric grid network. Shared mobility systems can ameliorate the high price of these technologies. However, the shared mobility system poses additional problems such as users’ waiting time, inconvenience, and increased VMT. Further, the impact of these emerging technologies varies on different groups of users (different values of travel time (VOTT). Another hurdle to the adoption of EVs is the limited range and scarcity of charging infrastructure. A well-established network of charging infrastructure, especially the direct current fast chargers (DCFC), can alleviate this challenge. However, the widespread adoption of EVs and the growing network of DCFC stations will increase the electric energy demand affecting the electric grid stability, demand-supply imbalance, overloading, and degradation of the electric grid components. Distributed energy resources (DER) such as solar panels and energy storage systems (ESS) can support the EV demand and reduce the load on the electric grid. This study develops modeling frameworks for the optimal adoption of AVs and EVs, considering their effect on transportation systems, the environment, and the electric grid network. Further, it suggests different scenarios that would promote the adoption of these technologies and provide a sustainable and resilient system.This study proposes a multi-objective mathematical model to estimate the optimal fleet configuration in a system of private manual-driven vehicles (PMVs), private AVs (PAVs), and shared AVs (SAVs) while minimizing the purchase and operating costs, time (travel and waiting time), and emission production. SAVs can be the optimal solution with the efficient use of travel time or the purchase price below a certain relative threshold. PAVs can be the optimal solution only if the onboard amenities are improved, lifetime mileage is increased, AV technology is installed in luxurious cars, and adopted by people with high VOTT. The framework is extended to consider different combinations of EVs, AVs, and conventional human-driven vehicles in a private and shared mobility system. The metaheuristics based on genetic and simulated annealing algorithms are developed to solve the large-scale NP-hard nonlinear optimization problem. The model is implemented for the network of Ann Arbor, Michigan. The results suggest that EVs are optimal for the system due to low operating costs and zero tailpipe emissions. Shared autonomous electric vehicles (SAEVs) are the best option for users with low VOTT. Private autonomous electric vehicles (PAEVs) would favor the system if the travel time savings are at least 20% or the price of AV technology is less than one-third of the vehicle price. The study then investigates the optimum investment technology to support the rising energy demand at the DCFC stations and reduce the load on the electric grid network. The different investments include purchasing and installing various ESS (new batteries (NB), second-life batteries (SLB), flywheels), solar panels, electric grid upgrades, and the cost of buying/selling electricity from/to the electric grid. The model is implemented for the DCFC stations supporting the future needs of EV charging demand for urban trips in the major cities of Michigan in 2030. The combination of SLBs and solar panels provides maximum benefits. The total annual and electricity savings are $25,000-$165,000 and $40,000-$300,000 per city.
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- Title
- A PILOT STUDY OF WEB-BASED INFORMATION BOTTLENECK IDENTIFICATION IN AEC PROJECTS
- Creator
- Pandey, Nishchhal Nihal
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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The success of the Architecture, Engineering, and Construction (AEC) project relies heavily on the effective communication and information exchange between project team members. A prominent reason for delays and progress shortcomings in AEC project teams is information bottlenecks, defined as missing project information bits which can be due to large influx of information or inadvertent withholding of information at a particular time. Information bottlenecks both in planning and execution...
Show moreThe success of the Architecture, Engineering, and Construction (AEC) project relies heavily on the effective communication and information exchange between project team members. A prominent reason for delays and progress shortcomings in AEC project teams is information bottlenecks, defined as missing project information bits which can be due to large influx of information or inadvertent withholding of information at a particular time. Information bottlenecks both in planning and execution phases of the project tend to cause schedule delays and cost overruns. Information and communication exchange patterns between project team members shed a light on the possible occurrence of information bottlenecks. Recent literature efforts have focused on use of software programming and key performance indicators (KPIs) to identify which phases of project are prone to occurrence of bottlenecks. One of the roadblocks in implementing majority of bottleneck identification techniques in AEC projects is the difficulty in execution. Some of the metrics defined are too complex and require rigorous manual calculations. Given the complexity and feasibility difficulties of the present methodologies for identification of bottleneck, this study aims to contribute to the body of knowledge by providing an adaptable tool that aims to improve the accuracy and practicality for predicting bottlenecks. Therefore, the research question this research aims to answer is “Can the usability and adaptability of information bottleneck prediction in AEC projects be improved through a web-based tool?”Expanding on Lean Construction concepts, key performance indicators (KPIs), efficiency, quantification metrics are developed to study the trends of information shared between AEC project team members. The developed model is semi-automated and reads data by importing the Microsoft Excel sheet which has all the raw project documentation data. A Python code developed by the researcher is used to extract information from the excel, create a dashboard, and publish information bottleneck calculations through a web-based tool. Statistical inferences drawn from the model are then be used to identify occurrence of project bottlenecks. The web-based platform is designed to cater the specific information exchange trends in a typical project. Providing visual representations, and explanations further ease the understanding of the root issue. Finally, through two expert interviews, the web tool is revised, and final tool is presented, and future directions of work are discussed.
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- Title
- INDIGENOUS MENTAL HEALTH : EXAMINING POPULATIONS IN TRIBAL AREAS AND NON-TRIBAL AREAS
- Creator
- Nash, Madeline
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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In this paper, I hypothesize that Indigenous populations in tribal areas fare better than those populations residing outside of tribal areas because of stronger social ties due to higher levels of integration and regulation. I review some of the studies that have been undertaken to measure mental health outcomes and suicide rates for the Indigenous populations in the US and Canada, paying close attention to the studies that describe differences between populations residing in tribal areas...
Show moreIn this paper, I hypothesize that Indigenous populations in tribal areas fare better than those populations residing outside of tribal areas because of stronger social ties due to higher levels of integration and regulation. I review some of the studies that have been undertaken to measure mental health outcomes and suicide rates for the Indigenous populations in the US and Canada, paying close attention to the studies that describe differences between populations residing in tribal areas compared to those who do not. I then use a panethnicity/race as a fundamental cause approach to explain why Indigenous populations have disparate mental health outcomes compared to the rest of the population, utilizing structural genocide to explain diminished integration and regulation. Pooling data from the National Drug Use and Health Survey (NSDUH), 2014-2017, I test this hypothesis controlling for sociodemographic variables. The results are mixed. On measures of serious psychological distress (SPD), my results are consistent with Park-Lees et al (2018). findings that there is no significant difference between these populations. However, there is a significant difference in serious thoughts of suicide. This contradicts Park-Lee et al. findings that though people residing in tribal areas had a lower rate than those who resided outside of tribal areas—the difference was not statistically significant using a T-test (2018). I found in my regression that after controlling for gender, age, marital status, education and income that living in tribal areas lowered one’s odd of having serious thought of suicide by over 30%.
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- Title
- ESSAYS ON COMMUNITY FOCUSED SUPPLY CHAINS
- Creator
- Cole, Dustin
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Businesses are increasingly being called upon to improve their Environment, Social and Governance (ESG) performance. The need to tackle a range of concerns, both environmentally and socially, can be seen in the United Nations’ 17 development goals set forth in 2015. Beyond governments and regulators, businesses themselves are increasingly aware of the importance of addressing such issues. Two hundred of the top CEOs of the country have emphasized the importance of the role that businesses...
Show moreBusinesses are increasingly being called upon to improve their Environment, Social and Governance (ESG) performance. The need to tackle a range of concerns, both environmentally and socially, can be seen in the United Nations’ 17 development goals set forth in 2015. Beyond governments and regulators, businesses themselves are increasingly aware of the importance of addressing such issues. Two hundred of the top CEOs of the country have emphasized the importance of the role that businesses play in confronting community-related issues and Diversity, Equity and Inclusion (DEI) (Murray 2019). In a series of three essays, this dissertation focuses on the social and environmental sustainability aspects of ESG, thus contributing substantially to the overall domain of sustainability. The first essay examines the impact of leader-worker disability status similarity on front-line manufacturing worker productivity using micro-data gathered from a real-world organization in Michigan. It contributes to the nascent field of inclusive operations and explores how organizations can both be profitable and inclusive of traditionally marginalized workers. The essay focuses on the moderating influence of direct supervisors with a disability on workgroup productivity as the number of workers with disabilities increases. Results suggest that a direct supervisor with a disability does indeed benefit the productivity of workers with disabilities. This benefit, however, is the mitigation of potential productivity declines as the number of workers with a disability increases in the workgroup. A follow-up qualitative study is performed to understand the mechanisms of the productivity benefit by interviewing 50 workers and supervisors with and without disabilities across three organizations. The second and third essays focus on the issue of water, a resource that is increasingly important as an environmental concern. As a resource shared between communities and firms, water is an essential component of building sustainable cities and communities.The second essay examines trade-offs and synergies experienced by organizations when reducing water use and carbon emissions using secondary panel data of large firms. Previous research has found differing results of organizations trading off carbon emissions and water. Some have found reducing one comes at the expense of the other, while other research has found organizations can reduce these two concerns jointly. This past research, though, has generally been qualitative and at the facility level, without quantitative analysis at the firm level. This research fills this gap by providing a firm-level examination of such potential trade-offs using a combination of Data Envelopment Analysis and econometric methods.The third essay uses a vignette experiment with real-world procurement professionals to examine how buyers weigh the competing environmental concerns of carbon emissions and water use reductions in the supply chain against supplier location (local vs. offshore suppliers). The results show an overwhelming preference for local suppliers with lower carbon emissions, to the extent that a supplier with a superior overall environmental performance may be passed over in pursuit of local suppliers with marginally lower carbon emissions.
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- Title
- EXPLORING THE RELATIONSHIP BETWEEN RESILIENCE AND ADVERSE IMPACT OF STUTTERING
- Creator
- Grobbel, Hannah
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Children who stutter often experience adverse impact such as bullying, negative thought patterns, and reduced self-esteem that result from living with their condition. Research suggests that there are factors that may place a child who stutters at greater risk for adverse impact as well as protective factors that mitigate this risk. The aim of this study is to examine the relationship between resilience and stuttering’s adverse impact in children. Resilience reflects both internal factors...
Show moreChildren who stutter often experience adverse impact such as bullying, negative thought patterns, and reduced self-esteem that result from living with their condition. Research suggests that there are factors that may place a child who stutters at greater risk for adverse impact as well as protective factors that mitigate this risk. The aim of this study is to examine the relationship between resilience and stuttering’s adverse impact in children. Resilience reflects both internal factors such as grit and the ability to cope and external factors such as family support and access to resources. We collected data from children who stutter and their parents to assess children’s resilience and stuttering’s adverse impact using standardized assessments. We then explored the relationship between resilience and adverse impact through descriptive statistics, linear regression, and correlation analyses. Results revealed that even children in the youngest, preschool-aged group showed adverse impact due to stuttering. We also found that greater resilience predicted less adverse impact in in school-aged and adolescent children who stutter. These findings provide insight into the experience of stuttering and offer support for treatments that incorporate resilience building into therapy to help mitigate adverse impact experienced by children who stutter.
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- Title
- ENHANCING CORPORATE CRIME ENFORCEMENT WITH MACHINE LEARNING—A MULTIDISCIPLINARY RISK FACTOR APPROACH
- Creator
- Chan, Fiona
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Despite its severe and lasting social and financial ramifications, corporate financial crime remains one of the most understudied crime types, as it is often hindered by two challenges. First, its multidisciplinary nature requires both financial and criminological expertise among others to conduct proper investigations. Second, corporate crime data is fraught with constraints such as high dimensionality, complex interactions, and nonlinear functional forms that are ill-suited for classical...
Show moreDespite its severe and lasting social and financial ramifications, corporate financial crime remains one of the most understudied crime types, as it is often hindered by two challenges. First, its multidisciplinary nature requires both financial and criminological expertise among others to conduct proper investigations. Second, corporate crime data is fraught with constraints such as high dimensionality, complex interactions, and nonlinear functional forms that are ill-suited for classical statistical modeling. The lack of research coupled with the limited resources in corporate crime enforcement represent a great impediment to the advancement of fraud interventions. This dissertation seeks to overcome these specific challenges by unifying cross-disciplinary financial fraud research under a risk factor framework, and by leveraging recent advancements in artificial intelligence. The goal is to examine whether two machine learning algorithms—random forest and neural network—can be used to enhance corporate fraud risk detection/prediction beyond more commonly employed analytical techniques. Findings from the analysis showed that the random forest algorithm outperformed logistic regression and a naïve classifier in a 1:1 matched sample. The neural network performed better than a naïve classifier but slightly worse than logistic regression. Feature selection improved the algorithms’ predictive accuracy and ability to distinguish between classes even further. Despite promising results from the 1:1 matched sample, both machine learning algorithms struggled with a heavily imbalanced 1: many dataset, which represents a more realistic setting. With the implementation of an oversampling strategy and feature selection, the algorithms improved substantially in identifying the rare fraud cases, and showed promise of improvement with further research on imbalanced classification. Feature importance from the random forest classifier identified risk factors that are consistent with findings from prior studies. Measures of financial distress ranked lower in importance than measures of financial health, suggesting future research can build on prior findings on corporate strain to examine specific mechanisms. The analysis also identified auditor independence as a key concept of guardianship and opportunity structure that warrants further study. Findings from this research also have important methodological implications for corporate crime studies—namely, the need to improve measurements of organizational-level fraud risk factors.
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- Title
- GENDER EQUITY IN COMMUNITY SUSTAINABILITY : BREASTFEEDING AND INTIMATE PARTNER ABUSE
- Creator
- Bomsta, Heather D.
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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We live within a web, connected to our family, friends, communities, societies, nations and ultimately, the greater biome of the Earth. Healthy, thriving women and children benefit their communities; healthy women work to contribute to and help care for their families and friends, and healthy children are able to learn well at school and are best positioned to develop into healthy, able citizens. Unfortunately, the presence of intimate partner abuse (IPA) negatively impacts maternal and child...
Show moreWe live within a web, connected to our family, friends, communities, societies, nations and ultimately, the greater biome of the Earth. Healthy, thriving women and children benefit their communities; healthy women work to contribute to and help care for their families and friends, and healthy children are able to learn well at school and are best positioned to develop into healthy, able citizens. Unfortunately, the presence of intimate partner abuse (IPA) negatively impacts maternal and child health, resulting in lost productivity, missed schooling, increased healthcare costs, and in some cases the deaths of women and infants. IPA is a critical issue in community well-being and sustainability. This dissertation presents three studies focusing on better understanding dynamics around IPA that impact women and their children. The first two studies focus on how abuse impacts breastfeeding. Providing human milk for an infant has benefits for infants, lowering all causes of infant mortality and resulting in increased IQ and lifelong health benefits (Victora et al., 2016). Nursing an infant also benefits mothers by reducing postpartum hemorrhage, lowering the risk of postpartum depression and their lifetime risks of nine different types of cancer (Stuebe, 2009). These benefits accumulate across individuals, resulting in healthier mothers and children, better able to contribute to their families and communities. The first study uses a nationwide dataset from the Centers for Disease Control, the Pregnancy Risk Assessment and Monitoring survey (PRAMS), to quantitatively explore the relationship between reported physical abuse and breastfeeding initiation. The relationship between IPA and breastfeeding initiation is complex and the literature is not yet settled. This study contributes to the literature by using an alternate approach that is not definitive, but points toward new areas for future research. Working to resolve this question can help healthcare providers, IPA advocates and policy makers with better information to begin to shape interventions to support mothers coping with abuse. Breastfeeding matters to these mothers for health reasons, but also because it is one of the first major decisions they make for an infant and if they do not meet their breastfeeding goals, they often experience guilt, question their value as mothers (Jackson, DePascalis, Harrold & Fallon, 2020) and face a higher risk of postpartum depression (Gregory, Butz, Ghazarian, Gross & Johnson, 2015; Borra, Iacovou & Sevilla, 2015). The first hypothesis explored is that mothers reporting physical abuse will initiate breastfeeding at a lower rate than mothers reporting no physical abuse. Logistic regression confirmed mothers reporting physical violence initiate breastfeeding at a lower rate than their unabused counterparts. The relationship remains significant when controlling for race and maternal education, but marital status reverses the effect. Subsequent subgroup analyses show married women’s decisions around breastfeeding initiation to be significantly impacted by physical abuse, while unmarried abused mothers initiated breastfeeding at roughly the same rate as unmarried mothers reporting no physical violence. The second hypothesis focuses only on mothers reporting physical abuse and explores whether a ‘dose’ effect exists. Logistical regression again shows mothers who report physical abuse at two time points initiate breastfeeding at a lower rate than mothers reporting physical abuse at only one time point. This finding remained significant even when controlling for maternal education, race/ethnicity, and marital status. The second study is a qualitative exploration of mothers’ experience of living with an abusive partner while breastfeeding. While quantitative studies can estimate the size and direction of a phenomenon it does not tell us what is happening in the day-to-day life of people experiencing it. Qualitative research can raise the voices of women coping with abuse during the breastfeeding phase, who are the experts on their situations. It is also essential for those working to end abuse to understand how mothers and their decisions are constrained by abuse and how they use their agency to resist and survive. This study uses semi-structured interviews with thirteen mothers with infants under one year of age who lived with an abusive partner for some amount of time while breastfeeding/pumping. Using thematic content analysis, themes emerged around mothers using gender performativity, successfully and unsuccessfully, to attempt to stem the violence and chaos in their relationships. Mothers attempted to fulfill traditional female roles to appease abusive partners, used breastfeeding to protect themselves and their infants, and drew strength from family, friends, and medical/support professionals by fulfilling the ‘good mother’ role through breastfeeding. The third study examines organizational resilience for nonprofits, which often function as a key part of the social safety net by providing services to vulnerable populations and strengthening communities. Despite their essential nature, organizational resilience (OR) among nonprofits is not well studied. Finding no models specific to nonprofits, a model of OR from the for-profit sector was adapted and extended. The model adaptation focuses on financial resources, technical resources and social resources and expands each category to cover unique aspects of nonprofits that the for-profit OR model does not contain. The gap between OR and social-ecological resilience (SER) was also examined, and several SER concepts were added to enhance our nonprofit OR model. The adapted model is then illustrated through a case study of intimate partner abuse (IPA) agencies. Managers and frontline staff from eight IPA nonprofits in a Midwestern state were interviewed during the COVID-19 pandemic. The adapted model can be used by researchers and practitioners to better understand and evaluate OR not only in IPA agencies, but all nonprofits.
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- Title
- THE USE OF EQUIVALENCE-BASED INSTRUCTION TO TEACH GRADUATE STUDENTS SIMPLIFIED DEFINITIONS OF BEHAVIOR ANALYTIC TERMINOLOGY
- Creator
- Medlin, Grace
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Individuals who are pursuing their Board-Certified Behavior Analyst (BCBA) certification are required to have an effective understanding of applied behavior analysis (ABA) terminology. Hemwell (2020) used Equivalence Based Instruction (EBI) and Match-to-Sample (MTS) training to teach technical definitions of ABA terminology to first-year ABA students. Participants displayed limited emergent intraverbal responding and did not maintain emergent intraverbal responding. Hemwell (2020) speculated...
Show moreIndividuals who are pursuing their Board-Certified Behavior Analyst (BCBA) certification are required to have an effective understanding of applied behavior analysis (ABA) terminology. Hemwell (2020) used Equivalence Based Instruction (EBI) and Match-to-Sample (MTS) training to teach technical definitions of ABA terminology to first-year ABA students. Participants displayed limited emergent intraverbal responding and did not maintain emergent intraverbal responding. Hemwell (2020) speculated this was due to the length and complexity of the definitions. The current study was conducted to replicate and extend Hemwell (2020) to determine if using simplified definitions of ABA terminology was effective in promoting the acquisition, understanding, and maintenance of ABA terminology. Using a multiple probe across behaviors design replicated across participants, participants were exposed to 30 simplified ABA terms, along with definitions and examples via a MTS teaching method. Participants were assessed on their performance of untaught relations in a selection-based pre-post assessment, as well as through a written intraverbal probes. Despite text simplification, emergent intraverbal responding was variable and did not maintain for all terms. However, emergent selection-based responding across all relations from pre to post test was evident. In addition, following text simplification, participants displayed emergent selection based responding with more complex definitions from the Cooper et al. (2020) textbook. Overall, future instructors may consider the use of EBI and text simplification in their courses to teach ABA terminology, examples, and principles.
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- Title
- Accessible Communication for Teaching App Research and Prototype
- Creator
- Tetu, Imari Cheyne
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Academia has traditionally served students who are able-bodied and able-minded. To include students with physical and cognitive disabilities, colleges and universities need to consider forms of engagement and participation that do not place disabled students at a disadvantage. Remote learning tools, such as those available in Zoom and Microsoft Teams, provide alternate means of communication that would be useful in classes with face-to-face meetings. I propose an app for use in post-secondary...
Show moreAcademia has traditionally served students who are able-bodied and able-minded. To include students with physical and cognitive disabilities, colleges and universities need to consider forms of engagement and participation that do not place disabled students at a disadvantage. Remote learning tools, such as those available in Zoom and Microsoft Teams, provide alternate means of communication that would be useful in classes with face-to-face meetings. I propose an app for use in post-secondary hybrid and hyflex writing classrooms. This app will facilitate networked communication among student groups as well as between individual students and instructors. I use design and accessibility heuristics to develop the wireflow through iterative design with a focus on the varying needs of people with physical and cognitive disabilities.
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- Title
- COVID-19 information sharing on social media : Channels and Motives from the Kazakhstani people's perspective
- Creator
- Moldagaliyeva, Moldir
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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COVID-19 pandemic news has become popular and topical content for the last couple of years. And the wide usage of social media across the globe makes it easy to share information, including misinformation, about COVID-19. Although sharing news on social media has been actively studied in most western countries, little attempt has been made to look into the issue from the perspectives of developing countries where the amount of social media use has been increasing enormously over the last...
Show moreCOVID-19 pandemic news has become popular and topical content for the last couple of years. And the wide usage of social media across the globe makes it easy to share information, including misinformation, about COVID-19. Although sharing news on social media has been actively studied in most western countries, little attempt has been made to look into the issue from the perspectives of developing countries where the amount of social media use has been increasing enormously over the last years. Besides, almost nothing is known about the social media users’ choice of a particular platform when they decide to share information and misinformation, especially within the context of the COVID-19 pandemic. Therefore, this master’s thesis explored how motivation factors Kazakhstani people follow when sharing COVID-19 news shape their decision to share COVID-19 news on specific social media platforms and their COVID-19 misinformation sharing patterns.The study used a quantitative research method approach, surveying 288 people from Kazakhstan over 18 years old.
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- Title
- ASSESSMENT OF WATER TREATMENT TECHNOLOGIES FOR PER-AND POLYFLUOROALKYL SUBSTANCES (PFAS) IN MULTIPLE MATRICES
- Creator
- Maldonado , Vanessa
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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The ubiquitous presence of per-and polyfluoroalkyl substances (PFAS) in the environment resulted in extensive water contamination that poses a significant risk to human health and biota. Continuous research efforts aim to develop efficient treatment technologies to treat PFAS in water, break the PFAS accumulation cycle in the environment, and improve the efficiency of emerging technologies. In this thesis work, selected treatment technologies including electrochemical oxidation and...
Show moreThe ubiquitous presence of per-and polyfluoroalkyl substances (PFAS) in the environment resulted in extensive water contamination that poses a significant risk to human health and biota. Continuous research efforts aim to develop efficient treatment technologies to treat PFAS in water, break the PFAS accumulation cycle in the environment, and improve the efficiency of emerging technologies. In this thesis work, selected treatment technologies including electrochemical oxidation and dielectrophoresis-enhanced adsorption were used to assess and advance the state-of-the-art for PFAS remediation in multiple matrices, not previously addressed. A boron-doped diamond (BDD) flow-through cell was used to evaluate the electrochemical oxidation of perfluoroalkyl acids (PFAAs) in landfill leachates. Multiple leachates with a concentration of individual PFAAs in the range of 10^2 -10^4 ng/L were treated. The effect of current density and variability of the composition of leachates was investigated. Non-detect levels and >90% removal of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were reached for all leachates tested after electrochemical treatment. Although high removal efficiencies for long-chain PFAAs were obtained, high concentrations of short-chain PFAAs were generated and associated with the transformation of perfluoroalkyl acid (PFAA) precursor compounds.In the second part of this thesis research, the oxidative transformation of PFAA-precursors typically present in leachates was addressed for the first time. Target and suspect PFAS were identified in a landfill leachate and their concentrations during electrochemical treatment were quantified over time. Liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF) measurements of the leachate identified 53 PFAS compounds and 19 PFAS classes. Multiple PFAS were reported for the first time in landfill leachates. The evaluation of the intermediate and final products generated during the electrochemical treatment showed evidence of known electrochemical degradation pathways.Coupling destructive technologies (e.g., electrochemical oxidation) with concentration technologies (e.g., ion exchange (IX), adsorption) in a treatment train approach could reduce the treatment cost of destructive technologies and increase their feasibility. Therefore, in the next part of this work, electrochemical oxidation of PFAAs from the concentrated waste of IX still bottoms was assessed at laboratory and semi-pilot scales. The concentrated waste resulted from the treatment of PFAAs-impacted groundwater with IX resins. Multiple current densities were evaluated at laboratory scale and the optimum current density was used at the semi-pilot scale. The results at the laboratory and semi-pilot scales allowed for >99% and >94% removal of total PFAAs with 50 mA/cm^2, respectively. Defluorination values, energy consumption, and implications were discussed.The third matrix addressed for PFAS remediation was drinking water. Dielectrophoresis-enhanced adsorption was used for the removal of low concentrations of PFOA. This study introduced a coaxial-electrode cell (CEC) that allowed for the generation of a non-uniform electric field to enhance the adsorption of PFOA. Experiments were performed in batch and continuous-flow modes. The dielectrophoretic-enhanced adsorption in batch mode resulted in a 4, 7, and 8-fold increase in the removal of PFOA with 5, 25, and 50 V when compared to adsorption only. The performance of the CEC in continuous-flow mode allowed for an increase of up to 2.4-fold in the PFOA removal with 25 V. The results highlighted the benefits of using a dielectrophoresis-enhanced adsorption process for the removal of PFOA from water. Overall, results from this thesis contribute to the understanding of the electrochemical degradation of PFAS in multiple matrices and introduce an alternative process to enhance the widely used adsorption technology for PFAS removal. Treatment implications of each matrix are discussed and provide a clear baseline for future research, development, and scale-up of treatment technologies for PFAS remediation.
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- Title
- Navigating Ideology, Identity, and Emotion in the Context of English-Medium Higher Education : Zohra's Story
- Creator
- Zulick, Bethany
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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There is a growing prevalence of English-medium instruction (EMI) at universities around the world as a result of globalization and the internationalization of higher education. Although the English language is often the main language of these institutions, research shows that the local language often occupies an important position within these institutions. This linguistic environment places international students who do not speak the local language in a vulnerable position, and they may...
Show moreThere is a growing prevalence of English-medium instruction (EMI) at universities around the world as a result of globalization and the internationalization of higher education. Although the English language is often the main language of these institutions, research shows that the local language often occupies an important position within these institutions. This linguistic environment places international students who do not speak the local language in a vulnerable position, and they may face exclusion from social settings or have less access to some aspects of academic life as a result. The present study examines how ideology, identity, and emotion interact in one international student’s journey through her first year at an EMI institution in Kyrgyzstan as she navigates language use within the institution, cultivates her multilingual repertoire, and creates a place for herself in the institutional community. The findings of the study revealed how the focal participant, Zohra, was influenced by monolingual ideologies, viewing the institution as a primarily English-only space and attempting to uphold these norms through her own language use. Like other international students, Zohra also reported experiences of exclusion through the use of the local language, positioning her as an outsider and provoking a range of negative emotions in response. Zohra leveraged her strong English skills and strategically used the local language to construct a positive identity for herself as a full member of the university community. She also engaged in an iterative process of reflection as she compartmentalized her personally held language ideologies and managed her negative emotions surrounding language use to facilitate her adjustment to the university.
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- Title
- REACTIVE ION ENHANCED MAGNETRON SPUTTERING OF NITRIDE THIN FILMS
- Creator
- Talukder, Al-Ahsan
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Magnetron sputtering is a popular vacuum plasma coating technique used for depositing metals, dielectrics, semiconductors, alloys, and compounds onto a wide range of substrates. In this work, we present two popular types of magnetron sputtering, i.e., pulsed DC and RF magnetron sputtering, for depositing piezoelectric aluminum nitride (AlN) thin films with high Young’s modulus. The effects of important process parameters on the plasma I-V characteristics, deposition rate, and the properties...
Show moreMagnetron sputtering is a popular vacuum plasma coating technique used for depositing metals, dielectrics, semiconductors, alloys, and compounds onto a wide range of substrates. In this work, we present two popular types of magnetron sputtering, i.e., pulsed DC and RF magnetron sputtering, for depositing piezoelectric aluminum nitride (AlN) thin films with high Young’s modulus. The effects of important process parameters on the plasma I-V characteristics, deposition rate, and the properties of the deposited AlN films, are studied comprehensively. The effects of these process parameters on Young’s modulus of the deposited films are also presented. Scanning electron microscope imaging revealed a c-axis oriented columnar growth of AlN. Performance of surface acoustic devices, utilizing the AlN films deposited by magnetron sputtering, are also presented, which confirms the differences in qualities and microstructures of the pulsed DC and RF sputtered films. The RF sputtered AlN films showed a denser microstructure with smaller grains and a smoother surface than the pulsed DC sputtered films. However, the deposition rate of RF sputtering is about half of the pulsed DC sputtering process. We also present a novel ion source enhanced pulsed DC magnetron sputtering for depositing high-quality nitrogen-doped zinc telluride (ZnTe:N) thin films. This ion source enhanced magnetron sputtering provides an increased deposition rate, efficient N-doping, and improved electrical, structural, and optical properties than the traditional magnetron sputtering. Ion source enhanced deposition leads to ZnTe:N films with smaller lattice spacing and wider X-ray diffraction peak, which indicates denser films with smaller crystallites embedded in an amorphous matrix.
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- Title
- STUDIES ON DIVERSITY OF ALTERNARIA ALTERNATA ASSOCIATED WITH ALTERNARIA LEAF SPOT IN SUGAR BEET
- Creator
- Jayawardana, Malini Anudya
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Alternaria leaf spot (ALS) is one of the foliar diseases that can impact sugar beet. Recently, ALS has been an increasing issue in fields from several states in the United States including Michigan. One of the most common causative agents of ALS is Alternaria alternata. This same organism has been reported as a pathogen not only in sugar beet, but also in a number of other crops. Michigan is the second most agriculturally diverse state in the United States and a wide range of crops are grown...
Show moreAlternaria leaf spot (ALS) is one of the foliar diseases that can impact sugar beet. Recently, ALS has been an increasing issue in fields from several states in the United States including Michigan. One of the most common causative agents of ALS is Alternaria alternata. This same organism has been reported as a pathogen not only in sugar beet, but also in a number of other crops. Michigan is the second most agriculturally diverse state in the United States and a wide range of crops are grown in the state. Since A. alternata is a pathogen on a number of crops currently grown and associated with sugar beet crop rotation in Michigan, it is important to learn about the interactions between A. alternata and its hosts. Therefore, the current projects were carried out to examine some of the host-pathogen interactions in A. alternata with a focus on ALS in sugar beet. The first project addressed developing effective inoculation methods for ALS in the laboratory, greenhouse or in the field. An effective inoculation method for ALS in sugar beet is important for assessing potential management tools for ALS such as screening for resistance and for fungicide efficacy. A detached leaf assay and a greenhouse inoculation with the inoculum in 0.2% malt extract as an outside nutrient source indicated a significant difference between susceptible and resistant varieties for the disease. Field results showed a significant effect of inoculation in three out of four years but showed issues with other pathogens and still need further testing. However, preliminary evidence for a consistent inoculation was observed in 2021, where the inoculum in an outside nutrient source, similar to what we used in the greenhouse, gave higher disease severity than a non-inoculated control or water-suspended inoculum. The diversity of A. alternata was observed in the second and third projects. Aspects of the host range of A. alternata were examined by isolating the pathogen from four crops growing in Michigan and cross-inoculating each isolate across four hosts. All the A. alternata strains caused lesions on all four host crops tested regardless of the crop from which they originally were isolated. Therefore, the results supported a wide host range of A. alternata. Furthermore, genetic diversity of A. alternata was examined in the third project. A total of 48 A. alternata isolates, collected from four hosts in Michigan, and in-silico data for an additional 15 A. alternata isolates from different hosts in other geographic areas, were used in a genetic analysis using three loci. The phylogenetic tree in this study agreed with previous reports of a high level of genetic diversity for A. alternata. This was the first study to examine diversity on beet and indicated similar diversity to what has been observed on other crops like potato and apple. No clear separation was observed between A. alternata strains related to the host from which they were originally collected. This further supports a lack of host specialization of A. alternata among the diverse hosts examined. Therefore, care should be taken when including these crops in a crop rotation system. If these crops are grown in rotation, the potential for disease development needs to be considered for appropriate management. The pathogen diversity also has implications for screening for host resistance.
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- Title
- Supervised Dimension Reduction Techniques for High-Dimensional Data
- Creator
- Molho, Dylan
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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The data sets arising in modern science and engineering are often extremely large, befitting the era of big data. But these data sets are not only large in the number of samples they have, they may also have a large number of features, placing each data point in a high-dimensional space.However, unique problems arise when the dimension of the data has the same or even greater order than the sample size. This scenario in statistics is known as the High Dimension, Low Sample Size problem (HDLSS...
Show moreThe data sets arising in modern science and engineering are often extremely large, befitting the era of big data. But these data sets are not only large in the number of samples they have, they may also have a large number of features, placing each data point in a high-dimensional space.However, unique problems arise when the dimension of the data has the same or even greater order than the sample size. This scenario in statistics is known as the High Dimension, Low Sample Size problem (HDLSS). In this paradigm, many standard statistical estimators are shown to perform sub-optimally and in some cases can not be computed at all. To overcome the barriers found in HDLSS scenarios, one must make additional assumptions on the data, either with explicit formulations or with implicit beliefs about the behavior of the data. The first type of research leads to structural assumptions placed on the probability model that generates the data, which allow for alterations to classical methods to yield theoretically optimal estimators for the chosen well-defined tasks. The second type of research, in contrast, makes general assumptions usually based on the the causal nature of chosen real-world data application, where the data is assumed to have dependencies between the parameters.This dissertation develops two novel algorithms that successfully operate in the paradigm of HDLSS. We first propose the Generalized Eigenvalue (GEV) estimator, a unified sparse projection regression framework for estimating generalized eigenvector problems.Unlike existing work, we reformulate a sequence of computationally intractable non-convex generalized Rayleigh quotient optimization problems into a computationally efficient simultaneous linear regression problem, padded with a sparse penalty to deal with high-dimensional predictors. We showcase the applications of our method by considering three iconic problems in statistics: the sliced inverse regression (SIR), linear discriminant analysis (LDA), and canonical correlation analysis (CCA). We show the reformulated linear regression problem is able to recover the same projection space obtained by the original generalized eigenvalue problem. Statistically, we establish the nonasymptotic error bounds for the proposed estimator in the applications of SIR and LDA, and prove these rates are minimax optimal. We present how the GEV is applied to the CCA problem, and adapt the method for a robust Huber-loss based formulation for noisy data. We test our framework on both synthetic and real datasets and demonstrate its superior performance compared with other state-of-the-art methods in high dimensional statistics. The second algorithm is the scJEGNN, a graphical neural network (GNN) tailored to the task of data integration for HDLSS single-cell sequencing data.We show that with its unique model, the GNN is able to leverage structural information of the biological data relations in order to perform a joint embedding of multiple modalities of single-cell gene expression data. The model is applied to data from the NeurIPS 2021 competition for Open Problems in Single-Cell Analysis, and we demonstrate that our model is able to outperform top teams from the joint embedding task.
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- Title
- THE IMPACT OF THE AFFORDABLE CARE ACT ON UNINTENDED PREGNANCY
- Creator
- MacCallum-Bridges, Colleen Lynn
- Date
- 2022
- Collection
- Electronic Theses & Dissertations
- Description
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Background & Objectives: Nearly half of all pregnancies in the United States (US) are unintended (i.e., mis-timed or unwanted), and roughly 5% of US women experience an unintended pregnancy each year, suggesting the population-level need for contraceptives is not being met. Further, these pregnancies are experienced disproportionately by women who are younger, women of color, and women of lower socioeconomic status – indicating these groups are particularly underserved. The Patient Protection...
Show moreBackground & Objectives: Nearly half of all pregnancies in the United States (US) are unintended (i.e., mis-timed or unwanted), and roughly 5% of US women experience an unintended pregnancy each year, suggesting the population-level need for contraceptives is not being met. Further, these pregnancies are experienced disproportionately by women who are younger, women of color, and women of lower socioeconomic status – indicating these groups are particularly underserved. The Patient Protection and Affordable Care Act (ACA) had the potential to improve our ability to meet this population-level need by increasing access to and affordability of contraceptive products and services. There is evidence that the ACA increased health insurance coverage and is associated with an increase in the use of highly effective long-acting reversible contraceptives, but it is unclear whether these effects translated into fewer unintended pregnancies. Further, it is unknown whether these effects were equitably distributed across race and ethnicity. Thus, the objectives of this dissertation are to: 1) estimate the overall impact of the ACA on unintended pregnancy, and if evidence of an impact exists, describe the timing of this impact, 2) explore three mechanisms of the ACA by investigating the impact of three major provisions (i.e., the dependent coverage provision, Marketplace subsidies, and ACA insurance expansions), and 3) assess the impact of the ACA on racial/ethnic disparities in unintended pregnancy. Methods: Data from multiple cross-sectional cycles of the National Survey of Family Growth (NSFG) were used. NSFG uses a multistage probabilistic sampling methodology to survey non-institutionalized civilian men and women regarding family planning, marriage, divorce, and both general and reproductive health. I included sexually active female respondents aged 18-44 interviewed between 2006 and 2019 (n=25,426). To address objectives (1) and (2) I used a difference-in-differences approach to compare trends in unintended pregnancy between women who were eligible to benefit from the intervention (the overall ACA or one of the listed components), to that of women who were ineligible to benefit. Eligibility was determined by respondent age and income. To address objective (3), I used a pre/post analysis to explore how racial/ethnic disparities in unintended pregnancy differed prior to and following enactment of the overall ACA and its components. Results: There was evidence that: 1) the overall ACA was associated with a 2.1 percentage point (ppt) decrease in unintended pregnancy among eligible women, and this decrease was fairly consistent during and following the ACA’s implementation period, 2) the dependent coverage provision was associated with a large (8.2 ppt) decrease in unintended pregnancy among lower income young women, and 3) the disparities in unintended pregnancy between Hispanic and non-Hispanic (NH) White women and between NH Black and NH White women decreased by 2.9 ppt and 4.1 ppt, respectively, among eligible women following full implementation of the ACA. There was insufficient evidence that the Marketplace subsidies or insurance expansions were associated with unintended pregnancy, or that the dependent coverage provision, Marketplace subsidies, or insurance expansions were associated with racial/ethnic disparities in unintended pregnancy. Conclusions: The overall ACA and the dependent coverage provision may be associated with reductions in unintended pregnancy, and the magnitude of these associations appear to differ across sociodemographic subgroups (i.e., income, race/ethnicity) – holding implications for health equity. These findings provide insight regarding how the ACA works to influence reproductive health, and for whom – which is critical information for both researchers and public policy makers who seek to improve reproductive health and health equity.
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