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Title: SYNTHETIC BIOLOGY APPROACHES ESTABLISH THE FOUNDATION FOR SUSTAINABLE PRODUCTION OF HIGH VALUE TERPENOIDS
Creator: Bibik, Jacob David
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Plants have become a promising platform for sustainable bioproduction of an array of natural products and specialty chemicals. Of particular interest are terpenes and the functionalized terpenoids, which represent the largest and most diverse class of natural products. These natural products are commonly used commercially as major constituents of flavorings and fragrances, oils, pigments, and pharmaceuticals, while having many other applications. Given the diversity and structural complexity...
Show morePlants have become a promising platform for sustainable bioproduction of an array of natural products and specialty chemicals. Of particular interest are terpenes and the functionalized terpenoids, which represent the largest and most diverse class of natural products. These natural products are commonly used commercially as major constituents of flavorings and fragrances, oils, pigments, and pharmaceuticals, while having many other applications. Given the diversity and structural complexity of many terpenoids, they are often expensive and difficult, if not impossible, to chemically synthesize. Engineering these biosynthetic pathways in plant hosts may provide a sustainable platform to access terpenoids for industrial production. While plants offer a sustainable production platform, metabolic engineering for chemical production has largely focused on microbial hosts, and further development of strategies and tools for plant engineering is needed. In my dissertation, I have taken multi-pronged approaches to further develop sustainable bioproduction of terpenoids in plants. First, I developed strategies to optimize, re-target, and compartmentalize production of squalene, a C30 triterpene, within plant cells to improve yields in plants. Re-targeting the final steps in squalene production, farnesyl diphosphate synthase (FDPS) and squalene synthase (SQS), from the cytosol to plastids enabled compartmentalization of biosynthesis away from competing cytosolic enzymes. I then anchored an optimized FDPS and SQS pair to the surface of cytosolic lipid droplets through fusions to the Nannochloropsis oceanica Lipid Droplet Surface Protein (NoLDSP), where squalene can be sequestered and stored. Scaffolding the pathway to the surface of lipid droplets increased yields to more than twice that of plastidial targeting. Re-targeting this lipid droplet scaffolding to plastids, produced similar squalene yields as the soluble, plastid targeted pathway, and ameliorated some of the negative effects on photosynthesis. Second, I worked to engineer poplar, a bioenergy crop which emits large amounts of the hemiterpene isoprene, with these pathways as a platform for bioproduction and adding value to a bioenergy pipeline. Transformants were successfully created for plastid targeted squalene production, producing up to 0.63mg/gFW of squalene. The lipid droplet scaffolding strategies appeared toxic during tissue regeneration, suggesting a need for tissue specific engineering of these pathways in future iterations. Third, I developed a pipeline to identify, characterize, and engineer bidirectional promoters (BDPs), which enable divergent expression of two genes and improve gene stacking in plant constructs. As seen above with poplar, plant engineering is often limited by construct size, diverse promoter availability, and expression regulation, and a BDP library enables a range of expression in more compact constructs. I identified 34 BDPs from Populus trichocarpa and Arabidopsis thaliana, characterized their activity via Nicotiana benthamiana transient expression, and engineered select BDPs to further alter activities. Combining these BDPs with previously developed terminator sequences provided further regulation of expression. These genetic tools provide an array of expression activities and enable greater gene stacking options while offering the potential for more fine tuning of expression for multiple genes in a metabolic pathway. The work performed in this dissertation provide strategies to improve production of terpenoids in plants, establish production hosts, and engineer larger, complex pathways.
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Title: UNDERSTANDING DRIVERS OF PLANT MICROBIOME IN MICHIGAN AGRICULTURE : STUDIES OF THE APPLE ROOT ZONE AND COMMON BEAN SEEDS
Creator: Bintarti, Ari Fina
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Plant-associated microbial communities are crucial for plant health and fitness, and may enhance plant tolerance to various environmental stresses. As global climate change threatens crop production and increases demands on sustainable agriculture, harnessing the plant microbiome has become one potential strategy to address these issues. Thus, it is fundamental to understand the relative contributions of both the host plant as well as the environment in shaping the plant microbiome. Moreover,...
Show morePlant-associated microbial communities are crucial for plant health and fitness, and may enhance plant tolerance to various environmental stresses. As global climate change threatens crop production and increases demands on sustainable agriculture, harnessing the plant microbiome has become one potential strategy to address these issues. Thus, it is fundamental to understand the relative contributions of both the host plant as well as the environment in shaping the plant microbiome. Moreover, the response of plant microbiomes to stress and any consequences of microbiome stress responses for the host plants are poorly understood, though this information is critical to achieve a basis of knowledge for plant microbiome engineering. My research aimed to contribute to this knowledge by investigating the factors that structure root- and seed-associated microbial communities of two valuable crops for Michigan’s agricultural economy: apple and common bean. The first chapter of my dissertation aimed to assess the biogeography of bacterial, archaeal, fungal, and nematode communities in the root zone of apple trees, and to determine their relationships with each other and their changes over natural abiotic gradients across orchards. I also assessed the influence of plant cultivar on microbiome structure in the root zone. I found that root zone microbiome community structure was strongly affected by geographic location and edaphic properties of soil. The next chapter of my dissertation investigated the variability of seed endophyte community of common bean (Phaseolus vulgaris L.). My results showed that plant-to-plant variability under controlled growth conditions exceeded within-plant variability among seeds from different pods. My study developed protocols and added insights to the growing toolkit of approaches to understand the plant-microbiome engagements that support the health of agricultural and environmental ecosystems. The last chapter assessed the responses of common bean seed endophytes to drought stress in the field across two growing locations and four genotypes of common bean. To summarize, this work advances foundational knowledge of the seed microbiome as a critical component of the plant microbiome, and in the context of two key crops for Michigan agriculture.
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Title: Fidelity to the ACT SMART Toolkit : An Assessment of Implementation Strategy Fidelity
Creator: Tschida, Jessica
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Although evidence-based practices (EBPs) have been shown to improve a variety of outcomes for autistic children, they are often inconsistently implemented or not implemented in community settings where many autistic children primarily receive care. One multi-faceted implementation strategy that researchers have developed and tested in a pilot study to support the implementation of EBPs for ASD in community settings is The Autism Community Toolkit: Systems to Measure and Adopt Research-Based...
Show moreAlthough evidence-based practices (EBPs) have been shown to improve a variety of outcomes for autistic children, they are often inconsistently implemented or not implemented in community settings where many autistic children primarily receive care. One multi-faceted implementation strategy that researchers have developed and tested in a pilot study to support the implementation of EBPs for ASD in community settings is The Autism Community Toolkit: Systems to Measure and Adopt Research-Based Treatments (ACT SMART Toolkit). Here, we used a case study approach to assess fidelity to the toolkit during its pilot study (implementation strategy fidelity) using measures of adherence, dose, and participant responsiveness and examined the relationship between implementation strategy fidelity and EBP use in an exploratory analysis. Overall, we found that adherence, dose, and participant responsiveness to the ACT SMART Toolkit were high with some variability by toolkit phase and activity. However, our exploratory analysis was ultimately unequipped to evaluate the relationship between increased fidelity and increased EBP use given the limited sample size of the pilot study. Our case study evaluation provides one of the first models of considering fidelity in the context of multi-faceted implementation strategies as well as important insights into potential core and peripheral components of the ACT SMART Toolkit.
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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: 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: Towards Robust and Reliable Communication for Millimeter Wave Networks
Creator: Zarifneshat, Masoud
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The future generations of wireless networks benefit significantly from millimeter wave technology (mmW) with frequencies ranging from about 30 GHz to 300 GHz. Specifically, the fifth generation of wireless networks has already implemented the mmW technology and the capacity requirements defined in 6G will also benefit from the mmW spectrum. Despite the attractions of the mmW technology, the mmW spectrum has some inherent propagation properties that introduce challenges. The first is that free...
Show moreThe future generations of wireless networks benefit significantly from millimeter wave technology (mmW) with frequencies ranging from about 30 GHz to 300 GHz. Specifically, the fifth generation of wireless networks has already implemented the mmW technology and the capacity requirements defined in 6G will also benefit from the mmW spectrum. Despite the attractions of the mmW technology, the mmW spectrum has some inherent propagation properties that introduce challenges. The first is that free space pathloss in mmW is more severe than that in the sub 6 GHz band. To make the mmW signal travel farther, communication systems need to use phased array antennas to concentrate the signal power to a limited direction in space at each given time. Directional communication can incur high overhead on the system because it needs to probe the space for finding signal paths. To have efficient communication in the mmW spectrum, the transmitter and the receiver should align their beams on strong signal paths which is a high overhead task. The second is a low diffraction of the mmW spectrum. The low diffraction causes almost any object including the human body to easily block the mmW signal degrading the mmW link quality. Avoiding and recovering from the blockage in the mmW communications, especially in dynamic environments, is particularly challenging because of the fast changes of the mmW channel. Due to the unique characteristics of the mmW propagation, the traditional user association methods perform poorly in the mmW spectrum. Therefore, we propose user association methods that consider the inherent propagation characteristics of the mmW signal. We first propose a method that collects the history of blockage incidents throughout the network and exploits the historical blockage incidents to associate user equipment to the base station with lower blockage possibility. The simulation results show that our proposed algorithm performs better in terms of improving the quality of the links and blockage rate in the network. User association based only on one objective may deteriorate other objectives. Therefore, we formulate a biobjective optimization problem to consider two objectives of load balance and blockage possibility in the network. We conduct Lagrangian dual analysis to decrease time complexity. The results show that our solution to the biobjective optimization problem has a better outcome compared to optimizing each objective alone. After we investigate the user association problem, we further look into the problem of maintaining a robust link between a transmitter and a receiver. The directional propagation of the mmW signal creates the opportunity to exploit multipath for a robust link. The main reasons for the link quality degradation are blockage and link movement. We devise a learning-based prediction framework to classify link blockage and link movement efficiently and quickly using diffraction values for taking appropriate mitigating actions. The simulations show that the prediction framework can predict blockage with close to 90% accuracy. The prediction framework will eliminate the need for time-consuming methods to discriminate between link movement and link blockage. After detecting the reason for the link degradation, the system needs to do the beam alignment on the updated mmW signal paths. The beam alignment on the signal paths is a high overhead task. We propose using signaling in another frequency band to discover the paths surrounding a receiver working in the mmW spectrum. In this way, the receiver does not have to do an expensive beam scan in the mmW band. Our experiments with off-the-shelf devices show that we can use a non-mmW frequency band's paths to align the beams in mmW frequency. In this dissertation, we provide solutions to the fundamental problems in mmW communication. We propose a user association method that is designed for mmW networks considering challenges of mmW signal. A closed-form solution for a biobjective optimization problem to optimize both blockage and load balance of the network is also provided. Moreover, we show that we can efficiently use the out-of-band signal to exploit multipath created in mmW communication. The future research direction includes investigating the methods proposed in this dissertation to solve some of the classic problems in the wireless networks that exist in the mmW spectrum.
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Title: CLIMATIC VARIABILITY AND CHANGE IN THE MIDWESTERN UNITED STATES : IMPLICATIONS FOR NITROGEN LEACHING IN AGRICULTURAL SYSTEMS
Creator: Baule, William James
Date: 2022
Collection: Electronic Theses & Dissertations
Description: How has the background climate of the Midwestern United States changed over recent decades and how has this affected nitrate leaching? These are the core questions addressed in this dissertation, through three self-contained studies focused on different aspects of the climate-agriculture interface in the Midwestern United States. In Chapter 2, statistical methods are used to quantify the solar radiation biases present in a widely used reanalysis-based hydrometeorological dataset over space,...
Show moreHow has the background climate of the Midwestern United States changed over recent decades and how has this affected nitrate leaching? These are the core questions addressed in this dissertation, through three self-contained studies focused on different aspects of the climate-agriculture interface in the Midwestern United States. In Chapter 2, statistical methods are used to quantify the solar radiation biases present in a widely used reanalysis-based hydrometeorological dataset over space, implement statistical bias correction and interpolation to address the spatial nature of this bias, and quantify the impacts of the solar radiation bias and proposed correction on simulated maize yields and water stress. Correction of reanalysis solar radiation alone brought simulated yield and water usage more in line with simulations forced with in-situ solar radiation. Chapter 3 examines changes in precipitation, utilizing a unique approach to station screening during the period 1951-2019 over a region encompassing the Great Lakes and broader Midwestern regions, of the United States. A multiple tier procedure was utilized to identify high quality input data series from the Global Historical Climatology Network-Daily dataset. Temporal and spatial trends were analyzed for a broad range of related annual and seasonal indicators ranging from accumulated totals and frequency of threshold events to event duration and potential linkages with total precipitable water. Our analyses confirm the results of previous studies while providing unique insights to data quality and seasonality. The trends of the indicators in our study exhibited more cohesive spatial patterns and temporal similarities when compared with studies with different quality control criteria, illustrating the importance of quality control of observations in climatic studies and highlighting the complexity of the changing character of precipitation. In Chapter 4, System Approach to Land Use Sustainability, a process-based crop model was applied with gridded soil and meteorological data using a yield stability zone concept to simulate corn and soybean production in 14 Midwestern states at the sub-field scale during the 1989-2019 period. Five zones based on multi-year yield stability were simulated for each field at 30m x 30m resolution, with zones being relative to each individual field. Outputs were evaluated using a nitrogen balance approach to establish zone-specific statistical distributions of nitrate leaching across the 14 states, specifically highlighting periods with changing and highly variable precipitation. Results indicate that low stable, unstable hill tops, and unstable slope zones are associated with an outsized contribution to overall nitrate leaching and that unstable zones exhibit variable year-to-year response to weather tied to their position in the landscape. Spatial analysis of the results suggests leaching is tied to precipitation variability, water stress, and total precipitation amount. In aggregate, the chapters presented here highlight the interconnectedness of the soil-plant-atmosphere continuum to changes in hydrologic regime and sensitivity to the biases in the data used to conduct analyses, run models, and from which conclusions are drawn. The study findings shed light on the potential for improved management of agricultural fields and illustrate how process-based crop models can be useful for designing management practices to reduce environmental pollution and increase profits to producers.
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Title: EPIDEMIOLOGY, EVOLUTION, AND DIAGNOSTICS OF TUBERCULOSIS IN HUMANS AND ANIMALS
Creator: Hadi, Syeda Anum
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Tuberculosis control in animals and humans alike requires early detection of Mycobacterium tuberculosis complex as well as current knowledge about the transmission patterns of the disease in the respective populations. These two building blocks provide the foundation on which the disease control programs can build their policies to expediate control efforts. In this thesis we amalgamate molecular epidemiology, genomics, and proteomics. We studied the transmission pattern of M. tuberculosis...
Show moreTuberculosis control in animals and humans alike requires early detection of Mycobacterium tuberculosis complex as well as current knowledge about the transmission patterns of the disease in the respective populations. These two building blocks provide the foundation on which the disease control programs can build their policies to expediate control efforts. In this thesis we amalgamate molecular epidemiology, genomics, and proteomics. We studied the transmission pattern of M. tuberculosis and its evolution within a marginalized population. The patterns led to the identification of gaps in TB control policies in marginalized populations with little access to healthcare. Similarly, we studied the genomewide polymorphisms in a naturally attenuated strain - M. bovis strain Ravenel to elucidate possible mechanisms for its reduced virulence and pathogenicity. Insights gained from genome sequence analysis in conjunction with pathogenesis study for M. bovis Ravenel paved the pathway to defining the complex and multi-faceted reasons for attenuation of the oldest bacteria of the world. Next, pathogen-specific biomarkers were evaluated to assist in unambiguous disease detection across multiple host species. Discovery and validation of biomarkers work facilitated the field diagnostic applications for TB in animals and humans. This three-pronged approach developed in this study, understanding the genomic basis of attenuation, and enhanced field TB diagnostics in the animal-human interface.
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Title: CHARACTERIZATION OF MANUAL EXPLORATORY BEHAVIORS IN EARLY CHILDHOOD
Creator: Patel, Priya Prakashbhai
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Manual exploratory behaviors observed during early childhood have critical functional and clinical role in the motor development of a child (Lockman & Kahrs, 2017). This dissertation is aimed to (1) address the challenges faced in the quantitative analysis of these behaviors, (2) conduct quantitative analysis of two important manual exploratory behaviors, (3) extend the current knowledge on the effects of age and object properties on these behaviors beyond infancy by assessing them in...
Show moreManual exploratory behaviors observed during early childhood have critical functional and clinical role in the motor development of a child (Lockman & Kahrs, 2017). This dissertation is aimed to (1) address the challenges faced in the quantitative analysis of these behaviors, (2) conduct quantitative analysis of two important manual exploratory behaviors, (3) extend the current knowledge on the effects of age and object properties on these behaviors beyond infancy by assessing them in preschoolers. In Study 1, a machine learning (ML) -based automated classification system was developed as a proof-of-concept for the classification of manual exploratory behaviors that address the challenges encountered in the quantitative analysis of these behaviors. This system was developed using data from adult participants and it can currently classify three manual exploratory behaviors namely- rotation, throwing and fingering with substantially higher accuracy than chance level (average accuracy = 85.0 + 4.16%). Based on these findings, ML -based approach appears to be both- a feasible and a scalable alternative to conventional video coding for identifying the manual exploratory behaviors on time series; thereby, facilitating their quantitative assessment. In Study 2, quantitative assessment of two important manual exploratory behaviors- rotation and throwing was conducted along with the assessment of ML classifiers on data from children (3 – 5 years old). The ML classifiers showed substantial decrease in performance owing to differences in movements between children and adults as well as technical difficulties. Rotation behaviors became more variable and faster with increasing age while the characteristics of throwing behaviors were inconclusive of developmental differences across the three ages. In Study 3, the effects of age and three object properties (size, shape and texture) were assessed on the qualitative characteristics of manual exploratory behaviors in children (3 – 5 years old). Manual exploration of objects was driven at different levels by age and object properties in preschoolers. In terms of age, throwing behaviors were more common in the 3-year group while rotational behaviors in the 5-year group. In terms of the three object properties, object size and shape directed child’s hand preference in reaching objects while object size and texture influenced their manual exploratory behaviors. In addition, object texture was found to mainly influence child’s first interactions with the objects as the squeezing and fingering behaviors occurred more often during the first interactions with the objects. The findings suggest that the dynamic interplay between learning to perceive object properties and manually exploring them continues to develop and adapt beyond infancy. In summary, manual exploratory behaviors, similar to other motor behaviors, are influenced by different individual, task and environment factors. These effects continue beyond infancy and throughout early childhood. A thorough qualitative and quantitative assessment is required to fully understand their functional and clinical role in early childhood. For this, ML -based approach is recommended to address the challenges in their quantitative analysis and to facilitate the overall scope of investigating these behaviors.
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Title: Nucleon and pion gluon parton distribution function from lattice QCD calculation
Creator: Fan, Zhouyou
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Parton distribution functions (PDFs) are important to characterize the structure of the hadrons such as protons and neutrons. The contribution to the structure from quarks has been studied in detail during the past few decades. The structure in the gluon sector is also important but less studied. For high-energy hadrons, the gluon contribution dominates at small $x$, where $x$ is the momentum fraction carried by a quark or gluon. At large $x$, the uncertainty of the gluon PDF is large,...
Show moreParton distribution functions (PDFs) are important to characterize the structure of the hadrons such as protons and neutrons. The contribution to the structure from quarks has been studied in detail during the past few decades. The structure in the gluon sector is also important but less studied. For high-energy hadrons, the gluon contribution dominates at small $x$, where $x$ is the momentum fraction carried by a quark or gluon. At large $x$, the uncertainty of the gluon PDF is large, especially compared to that of the quark PDFs at large $x$. Gluon PDFs for nucleons and pions are mostly extracted from global analysis of experimental data using perturbation theory as a guide. Theoretically, lattice QCD provides an independent non-perturbative theoretical approach to calculate the gluon PDFs.We present the exploratory study of nucleon gluon PDFs from lattice QCD using the quasi-PDF approach. Using valence overlap fermions on the $2+1$-flavor domain-wall fermion gauge ensemble, the quasi-PDF matrix elements we obtain agree with the Fourier transform of the global-fit PDF within statistical uncertainty. We further study the $x$-dependent nucleon and pion gluon distributions via the pseudo-PDF approach on lattice ensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ) generated by the MILC Collaboration. Using clover fermions for the valence action, and adding momentum smearing, PDFs are found for pion boost momenta up to 2.56~GeV. Several lattice sizes and spacings ($a\approx 0.9, 0.12$ and 0.15~fm) were evaluated, resulting in three pion masses, $M_{\pi}\approx 220$, 310 and 690~MeV/$c^2$.
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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: 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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Title: THE MEASUREMENT OF PHYSICAL ACTIVITY SELF-EFFICACY IN INTERVENTIONS THAT PROMOTE PHYSICAL ACTIVITY IN ADULTS
Creator: Bateman, Andre Godfrey
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This dissertation comprises two studies focused on the measurement of self-efficacy associated with physical activity-promoting interventions in adults. Recent research indicates that most adults do not achieve sufficient daily physical activity for health. The research also shows that adults with obesity are even less likely to engage in sufficient physical activity for health. Physical inactivity is associated with negative health outcomes such as cardiovascular disease and is therefore a...
Show moreThis dissertation comprises two studies focused on the measurement of self-efficacy associated with physical activity-promoting interventions in adults. Recent research indicates that most adults do not achieve sufficient daily physical activity for health. The research also shows that adults with obesity are even less likely to engage in sufficient physical activity for health. Physical inactivity is associated with negative health outcomes such as cardiovascular disease and is therefore a major public health concern. There is however evidence that certain motivational constructs, such as self-efficacy are associated with increased physical activity in adults. As a result, behavioral interventions utilizing these constructs as modifiable mediators of physical activity behavior have been employed to increase physical activity in different populations.Study 1 is a systematic review focused on examining the theoretical and measurement quality of physical activity self-efficacy scales in physical activity-promoting interventions for adults. The search strategy was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. One hundred sixteen studies were reviewed, from which the physical activity self-efficacy scales were identified and extracted. Of the scales identified, 14 were multi-item and five were single item scales. The systematic review uncovered that the identified scales had varying conceptual and measurement related properties despite having good administrative quality in general. The major issues identified with self-efficacy measurement were: (a) a lack of concordance between self-efficacy and physical activity measurement, (b) a lack of specified physical activity levels to which the self-efficacy measurements refer, (c) self-efficacy scales described with theoretically imprecise construct labels, (d) a lack of emphasis on essential conceptual properties of self-efficacy scales, (e) a lack of specification of the dimensionality of self-efficacy scales and (f) the use of single-item measures of self-efficacy. Essential conceptual and measurement related recommendations were made in response to these issues to improve the measurement of physical activity self-efficacy in physical activity-promoting interventions. Study 2 employed a latent variable approach to explore the dimensionality, temporal invariance, and external validity of responses to the self-efficacy to regulate physical activity scale (SERPA). The SERPA is a modified version of the barriers self-efficacy scale. This study analyzed data from the Well-Being and Physical Activity Study (WBPA; ClinicalTrials.gov, identifier: NCT03194854). The WBPA consisted of 461 participants at baseline which decreased to 427 participants at 30 days post baseline. The WBPA deployed the Fun For Wellness (FFW) intervention. One objective of the FFW intervention was to promote physical activity in adults with obesity. A two-dimensional factor structure explained responses to the SERPA at baseline. Factor 1 was conceptualized as self-efficacy to regulate barriers to physical activity participation based on social considerations. Factor 2 was conceptualized as self-efficacy to regulate internally perceived barriers to physical activity participation. There was strong evidence for the effectiveness of the FFW intervention to exert a direct effect on the proposed two-dimensional structure of latent self-efficacy to regulate physical activity in adults with obesity at 30 days post-baseline.
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Title: A PLACE OF PERSONAL AND CULTURAL RESISTANCE : USING BLACK FEMINIST VALUES, PERSPECTIVES, AND EMBODIED KNOWLEDGES TO (RE)EXAMINE INSTITUTIONAL LOGICS AND ETHICS IN DIGITAL RESEARCH
Creator: Haywood, Constance Monique
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Centering the experiences and practices of Black women scholars who engage research in areas of Black technological and digital engagement, this dissertation examines how Black women and Black feminist-identifying digital researchers’ personal, cultural, and professional identities inform methodological and ethical decision-making in their work. Building on the theoretical approaches of Black feminist thinkers like Patricia Hill Collins and the Combahee River Collective, this project...
Show moreCentering the experiences and practices of Black women scholars who engage research in areas of Black technological and digital engagement, this dissertation examines how Black women and Black feminist-identifying digital researchers’ personal, cultural, and professional identities inform methodological and ethical decision-making in their work. Building on the theoretical approaches of Black feminist thinkers like Patricia Hill Collins and the Combahee River Collective, this project addresses the complexities of digital ethics by 1) examining how Black women’s unique, lived experience(s) both inform and are impacted by their work and 2) uncovering the processes that support -- and sometimes create tensions with -- research aroundBlack digital publics, users, and spaces. This project places a special focus on the work of Black women and Black feminist-identifying scholars in writing studies-related fields, collecting and analyzing data from multiple qualitative interviews amongst five research participants.Ultimately, this dissertation highlights the growing work and practices of Black women digital researchers, using Black feminist theory as a means to uncover how Black women researchers reconsider, repurpose, and reapproach their research practices from embodied and critical standpoints. This project also adds to growing conversations around the development ofdigital methodologies in writing and communication-related fields, particularly those that place a greater priority on researchers’ ethical responsibilities to multiple-marginalized technology users and communities.
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Title: Regulation of Chlamydomonas reinhardtii cell cycle during synchronous growth
Creator: Lin, Yang-Tsung
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of...
Show moreThe regulation of the cell cycle in microalgae has long been a central topic in third-generation biofuel studies, as it relates to biomass accumulation and lipid production, the two determining factors of economically feasible biofuel production. The discovery of Compromised Hydrolysis of TAG 7 (CHT7) in the green alga Chlamydomonas reinhardtii has provided valuable insights into the metabolic status-dependent regulation of the cell cycle. CHT7 belongs to the CHC protein family, members of which include transcriptional regulators programming the initiation of cell division. A similar role of CHT7 in mediating cell cycle progression has been suggested. However, the regulatory mechanism and specific processes regulated by CHT7 have yet to be determined. In this dissertation, I applied bioinformatics approaches to comprehensively study CHT7-mediated gene regulation during the cell cycle using cell cultures synchronously grown in bioreactors. I found that specific pathways such as DNA replication, chromosome condensation, and spindle assembly are affected by the absence of CHT7. Other affected pathways include cell-wall remodeling and previously uncharacterized putative kinase cascades. In addition, I discovered the presence of two potential cis-regulatory elements near the transcription start site of misregulated genes in cht7, which are potentially linked to homeodomain transcription factors. Moreover, I explored the potential relationship between the CHT7-mediated pathway and the gene network governed by the retinoblastoma protein complex. Lastly, I characterized the function of a novel CHC protein in cell cycle progression and compared it with the role of CHT7. Together, these studies facilitate a better understanding of the cell cycle regulation in microalgae.
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Title: Advancements in Applied Behavior Analysis Service Delivery, Supervision, and Feedback
Creator: Thomas, Emma
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Supervision is critical to the field of Applied Behavior Analysis (ABA) because it improves the quality of services provided to the recipients of behavioral services which in turn increases client protection and helps to portray the field of ABA as one that is committed to socially significant behavior change (Britton & Cicoria, 2019; Brodhead & Higbee, 2012; Hartley et al., 2016; LeBlanc & Luiselli, 2016; LeBlanc et al., 2020; Turner et al., 2016). Without effective supervision, the quality...
Show moreSupervision is critical to the field of Applied Behavior Analysis (ABA) because it improves the quality of services provided to the recipients of behavioral services which in turn increases client protection and helps to portray the field of ABA as one that is committed to socially significant behavior change (Britton & Cicoria, 2019; Brodhead & Higbee, 2012; Hartley et al., 2016; LeBlanc & Luiselli, 2016; LeBlanc et al., 2020; Turner et al., 2016). Without effective supervision, the quality of services may decrease and negatively impact treatment outcomes for the clients (Britton & Cicoria, 2019; Dixon et al., 2016; Eikeseth, 2009; LeBlanc & Luiselli, 2016; Shapiro & Kazemi, 2017). Given the rapid growth of the field of ABA, supervision will continue to play a critical role in training, fostering the growth and development of professionals and ensuring those professionals uphold the high standards of the profession (Hajiaghamohseni et al., 2020; Turner et al., 2016; Turner, 2017). The current dissertation addressed and evaluated supervision of behavior analytic services provided to individuals with autism spectrum disorder (ASD) in three different contexts: (1) supervision provided during the implementation of behavioral interventions, (2) supervision provided via Telehealth, specifically evaluating barriers and strategies used to address and/or mitigate those barriers, and (3) supervision provided via Telehealth in the form of email performance-based feedback. Collectively, these chapters sought to address gaps in the current behavior analytic supervision literature and identify additional areas of study. Chapter 1 provides an overall introduction connecting the three separate, but related chapters (Chapters 2-4) and includes a supervision logic model. Chapter 2 is a systematic literature review that evaluated the extent to which recently published articles included information regarding supervision and staff training of the individuals implementing behavioral interventions to young children with ASD. The results of Chapter 2 revealed that there is little to no consensus on reporting supervision and staff training characteristics in the current behavioral intervention literature. Research implications and reporting recommendations will be discussed. Chapter 3 is a survey study that evaluated the barriers Board Certified Behavior Analysts (BCBAs) experienced and the strategies BCBAs used to address and/or mitigate the barriers that arose when providing supervision via Telehealth. The results of Chapter 3 revealed that BCBAs that provide supervision via Telehealth are not exempt from experiencing barriers. Research and practical implications will be discussed. Chapter 4 is a single case research design study that evaluated the extent to which email performance-based feedback increased procedural fidelity of teacher candidates’ implementation of a multiple stimulus without replacement (MSWO) preference assessment. The results revealed that email performance-based feedback was effective in increasing procedural fidelity of MSWO preference assessment implementation. These results support previous literature suggesting that email performance-based feedback alone is effective in increasing target behavior(s). Research implications will be discussed. Finally, Chapter 5 provides an overall discussion about the findings of the three chapters (Chapters 2-4), recommendations for research and practice, and considerations for the future direction of supervision in the field of ABA.
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Title: DISCOURSES OF WELL-BEING OF ADOLESCENT GIRLS LIVING IN PATAGONIA, CHILE
Creator: Bilbao Nieva, Maria Isidora
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The term well-being entails material and subjective elements, and it is critical to promote it during adolescence. Access to opportunities and resources are key determinants to well-being, but not all adolescents have the same living conditions. In the specific case of adolescent girls living in Latin American countries, structural barriers to well-being are derived from gender and cultural factors that influence their everyday experiences. From a Community Psychology perspective, structural...
Show moreThe term well-being entails material and subjective elements, and it is critical to promote it during adolescence. Access to opportunities and resources are key determinants to well-being, but not all adolescents have the same living conditions. In the specific case of adolescent girls living in Latin American countries, structural barriers to well-being are derived from gender and cultural factors that influence their everyday experiences. From a Community Psychology perspective, structural factors are critical to well-being promotion and should be considered alongside individual-level factors.Using Feminist Critical Discourse Analysis, this study examined the discourses of well-being of ten adolescent girls from low-income families living in Coyhaique. The analysis was focused on how girls talk about what contributes to their well-being, with a specific focus on structural conditions that affect them. The results showed that while they spoke of individual-level factors contributing to their well-being, they also mentioned structural issues influenced by gender and culture. Those structural level factors were related to resources, support networks, and community environment. Implications for well-being promotion are discussed.
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Title: THE ROLE OF HOST-PARASITOID INTERACTIONS, RAPID EVOLUTION, AND HOST SHIFTS IN THE BIOLOGICAL CONTROL OF INVASIVE INSECT PESTS
Creator: Linder, Shelley Kay
Date: 2022
Collection: Electronic Theses & Dissertations
Description: This thesis focuses on two invasive species, spotted wing drosophila (Drosophila suzukii) and the brown marmorated stink bug (Halyomorpha halys). The first chapter investigates the potential of native parasitoids to increase their developmental success on D. suzukii. Two native parasitoids were subjected to 10 generations of selection on D. suzukii and fitness metrics were measured in generations 0, 3, and 10. Both parasitoid species responded rapidly to selection, reaching peak developmental...
Show moreThis thesis focuses on two invasive species, spotted wing drosophila (Drosophila suzukii) and the brown marmorated stink bug (Halyomorpha halys). The first chapter investigates the potential of native parasitoids to increase their developmental success on D. suzukii. Two native parasitoids were subjected to 10 generations of selection on D. suzukii and fitness metrics were measured in generations 0, 3, and 10. Both parasitoid species responded rapidly to selection, reaching peak developmental success on the novel host within three generations, which they then maintained for seven additional generations. There was no increase in preference towards the novel host or changes in development time or body size associated with adaptation. The sex ratio became less female biased for both parasitoids after three generations of selection but rebounded in one species by generation 10. These results indicate that artificial selection can increase the performance of native parasitoids within a few generations and may be used to improve biocontrol when co-adapted natural enemies of invasive species are not available. The second chapter investigates how the fitness of the adventive parasitoid of H. halys, Trissolcus japonicus, may change in response to intermittent or continuous exposure to a non-target native stink bug species. Acceptance of the native stink bug species did not increase with either intermittent or continuous exposure. However, reproduction on the native host resulted in a significant fitness cost for T. japonicus and compromised the fitness of the parasitoid on its original host species. These results suggest that non-target effects of T. japonicus may remain insignificant in nature given the fitness cost of attacking native species.
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Title: Variational Bayes inference of Ising models and their applications
Creator: Kim, Minwoo
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Ising models originated in statistical physics have been widely used in modeling spatialdata and computer vision problems. However, statistical inference of this model and its application to many practical fields remain challenging due to intractable nature of the normalizing constant in the likelihood. This dissertation consists of two main themes, (1) parameter estimation of Ising model and (2) structured variable selection based on the Ising model using variational Bayes (VB).In Chapter 1,...
Show moreIsing models originated in statistical physics have been widely used in modeling spatialdata and computer vision problems. However, statistical inference of this model and its application to many practical fields remain challenging due to intractable nature of the normalizing constant in the likelihood. This dissertation consists of two main themes, (1) parameter estimation of Ising model and (2) structured variable selection based on the Ising model using variational Bayes (VB).In Chapter 1, we review the background, research questions and development of Isingmodel, variational Bayes, and other statistical concepts. An Ising model basically deal with a binary random vector in which each component is dependent on its neighbors. There exist various versions of Ising model depending on parameterization and neighboring structure. In Chapter 2, with two-parameter Ising model, we describe a novel procedure for the pa- rameter estimation based on VB which is computationally efficient and accurate compared to existing methods. Traditional pseudo maximum likelihood estimate (PMLE) can pro- vide accurate results only for smaller number of neighbors. A Bayesian approach based on Markov chain Monte Carlo (MCMC) performs better even with a large number of neighbors. Computational costs of MCMC, however, are quite expensive in terms of time. Accordingly, we propose a VB method with two variational families, mean-field (MF) Gaussian family and bivariate normal (BN) family. Extensive simulation studies validate the efficacy of the families. Using our VB methods, computing times are remarkably decreased without dete- rioration in performance accuracy, or in some scenarios we get much more accurate output. In addition, we demonstrates theoretical properties of the proposed VB method under MF family. The main theoretical contribution of our work lies in establishing the consistency of the variational posterior for the Ising model with the true likelihood replaced by the pseudo- likelihood. Under certain conditions, we first derive the rates at which the true posterior based on the pseudo-likelihood concentrates around the εn- shrinking neighborhoods of the true parameters. With a suitable bound on the Kullback-Leibler distance between the true and the variational posterior, we next establish the rate of contraction for the variational pos- terior and demonstrate that the variational posterior also concentrates around εn-shrinking neighborhoods of the true parameter.In Chapter 3, we propose a Bayesian variable selection technique for a regression setupin which the regression coefficients hold structural dependency. We employ spike and slab priors on the regression coefficients as follows: (i) In order to capture the intrinsic structure, we first consider Ising prior on latent binary variables. If a latent variable takes one, the corresponding regression coefficient is active, otherwise, it is inactive. (ii) Employing spike and slab prior, we put Gaussian priors (slab) on the active coefficients and inactive coefficients will be zeros with probability one (spike).
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Title: Multiple Jeopardy, Serious Mental Illness, and Service Attendance
Creator: Reid, Mallet R.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: For people with Serious Mental Illness (SMI), attendance to behavioral health care services is linked to a an increased probability of recovery and a decreased risk for suicide, involuntary hospitalization, incarceration, mental distress, and preventable mortality. Within the population of people with SMI, women and men who are Black, Indigenous, and other People of Color (BIPoC) are most likely to experience barriers to services and are the least likely groups to attend services. Thus, most...
Show moreFor people with Serious Mental Illness (SMI), attendance to behavioral health care services is linked to a an increased probability of recovery and a decreased risk for suicide, involuntary hospitalization, incarceration, mental distress, and preventable mortality. Within the population of people with SMI, women and men who are Black, Indigenous, and other People of Color (BIPoC) are most likely to experience barriers to services and are the least likely groups to attend services. Thus, most studies examining behavioral health care attendance trends for people with SMI focus on the relationship between marginalized race and/or sex and barriers to service attendance. However, few studies examine the relationship between barriers and attendance among those who occupy multiple marginalized identity groups. This study seeks to fill that gap. Using Multiple Jeopardy theory, which asserts that membership in multiple marginalized groups increases the risk of experiencing negative life events, this study examines the impact of holding multiple marginalized social group identities and of experiencing barriers to attendance on the probability of attending behavioral health services among people with SMI.
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Title: WISDOM FROM A MENTOR IN A MATTER OF MINUTES : INVESTIGATING A PROPOSED MODEL OF FLASH MENTORSHIP IN STUDENT-ALUMNI INTERACTIONS
Creator: Wisner, Amy Marie
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Mentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In...
Show moreMentoring is an age-old practice that proves meaningful for protégés across contexts and program designs. Because both mentoring practice and mentoring research take place in a wide variety of domains and with seemingly limitless program details, it has become difficult to define or execute with any precision. Mentoring practitioners and researchers would benefit greatly from a mentorship model to inform their program designs and selection of mentoring type best-suited to the situation. In recent years, a type of mentoring that has gained popularity is flash mentorship. This short-term, one-time interaction is desirable because of the limited commitment required for everyone involved. However, little is known about the effectiveness of this type of mentorship. The current work sought to develop a model of effective flash mentorship with the broader goal of establishing best practices for pairing mentors with protégés in meaningful ways. A proposed model of flash mentorship posited that relationship quality and advice quality predicted protégé situational satisfaction. Antecedents of relationship quality were posited to include attraction and deep-level similarity. Antecedents of advice quality were posited to include message features and mentor expertise. Although all causal links posited by the model were of sufficient magnitude to be consistent with predictions, the fit of the model proved insufficient. Limitations of the findings and recommendations for future research are discussed.
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Title: COLLECTIVE ACTION AND SEED PRODUCTION : A PATHWAY FOR WOMEN'S EMPOWERMENT AND COMMUNITY SEED SECURITY IN INDIA
Creator: Lewis, Arena
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There exists a wide range of development interventions that aim to 1) empower women and 2) ensure food security for rural smallholder farmers. These types of interventions, implemented separately, have had varied success. The implementation of interventions to achieve both women’s empowerment and seed security simultaneously has been researched in a few studies, but the successful achievement of these goals has rarely been observed. This study investigates the impact a layered seed production...
Show moreThere exists a wide range of development interventions that aim to 1) empower women and 2) ensure food security for rural smallholder farmers. These types of interventions, implemented separately, have had varied success. The implementation of interventions to achieve both women’s empowerment and seed security simultaneously has been researched in a few studies, but the successful achievement of these goals has rarely been observed. This study investigates the impact a layered seed production/self-help group program had on women’s empowerment and seed security. The research was conducted in 2 districts in Uttar Pradesh, India using semi-structured interviews of 36 participants. The findings indicate that, through the collective power of self-help groups, women were empowered and seed security was increased for women within the group as well as the greater community through the seed production program. Further, women who participated in the seed production program in addition to their regular self-help group membership, were empowered through additional channels specific to the layered seed production systems. This research indicates that self-help groups can act as a platform for development interventions and integrate well with seed system interventions.
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