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Title: Robust Maxwell Solvers for Large Scale Particle-in-Cell Simulations
Creator: Crawford, Zane Daniel
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The design of modern devices is impacted heavily by the use and availability of robust, accurate, and efficient computational tools. This includes modeling devices that exploit plasma physics like particle accelerators, klystrons, ion thrusters, and micro-plasma generators among many other applications. While there are a number of current and emerging applications, the common thread between all is the need to accurately and efficiently capture all the relevant physics in geometrically...
Show moreThe design of modern devices is impacted heavily by the use and availability of robust, accurate, and efficient computational tools. This includes modeling devices that exploit plasma physics like particle accelerators, klystrons, ion thrusters, and micro-plasma generators among many other applications. While there are a number of current and emerging applications, the common thread between all is the need to accurately and efficiently capture all the relevant physics in geometrically intricate structures. The holy grail is to enable topology optimization to explore the design space. But all this requires rigorous translation from the continuous to the discrete world, while capturing all the underlying physics and not adding spurious artifacts due to discretization.A common computational model to perform this analysis is the particle-in-cell (PIC) method. It provides a straightforward paradigm to self-consistently solve for the distribution of the plasma as a collection of particles. The prevailing approach to solve for the fields in PIC is the finite difference time domain method (FDTD), or EM-FDTDPIC. But this effort leaves much to be desired, given the leaps that have been made in the finite element method; indeed, the latter is the method of choice for most commercial tools that that have become the de-facto workhorse in RF design industry. As a result, in the past decade, considerable effort has been expended in developing finite element (FEM) based PIC schemes, EM-FEMPIC. But we are still not there. One major concern of utilizing EM-FEMPIC over EM-FDTDPIC is the computational cost of FEM, which is greater than FDTD, despite the advantages of field and geometry accuracy FEM affords.This dissertation seeks to develop (i) a theoretically rigorous means to translate from the continuous to the discrete world while ensuring that there are no spurious artifacts, (ii) develops a higher order accurate method in both space and time, and (iii) overcomes cost complexity by introducing a linear scaling domain decomposition scheme. In all of these, the methods developed ensure that the necessary conservation properties are satisfied to machine precision. Numerous examples developed demonstrate these claims.
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Title: Machine Learning on Drug Discovery : Algorithms and Applications
Creator: Sun, Mengying
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Drug development is an expensive and time-consuming process where thousands of chemical compounds are being tested and experiments being conducted in order to find out drugs that are safe and effective. Modern drug development aims to speed up the intermediate steps and reduce cost by leveraging machine learning techniques, typically at drug discovery and preclinical research stages. Better identification of promising candidates can significantly reduce the load of later processes, e.g.,...
Show moreDrug development is an expensive and time-consuming process where thousands of chemical compounds are being tested and experiments being conducted in order to find out drugs that are safe and effective. Modern drug development aims to speed up the intermediate steps and reduce cost by leveraging machine learning techniques, typically at drug discovery and preclinical research stages. Better identification of promising candidates can significantly reduce the load of later processes, e.g., clinical trials, saving tons of resources as well as time.In this dissertation, we explored and proposed novel machine learning algorithms for drug discovery from the aspects of robustness, knowledge transfer, molecular generation and optimization. First of all, labels from high-throughput experiments (e.g., biological profiling and chemical screening) often contain inevitable noise due to technical and biological variations. We proposed a method that leverages both disagreement and agreement among deep neural networks to mitigate the negative effect brought by noisy labels and better predict drug responses. Secondly, graph neural networks (GNNs) has become popular for modeling graph-structured data (e.g., molecules). Graph contrastive learning, by maximizing the mutual information between paired graph augmentations, has been shown to be an effective strategy for pretraining GNNs. However, the existing graph contrastive learning methods have intrinsic limitations when adopted for molecular tasks. Therefore, we proposed a method that utilizes domain knowledge at both local- and global-level to assist representation learning. The local-level domain knowledge guides the augmentation process such that variation is introduced without changing graph semantics. The global-level knowledge encodes the similarity information between graphs in the entire dataset and helps to learn representations with richer semantics. Last but not least, we proposed a search-based approach for multi-objective molecular generation and optimization. We show that given proper design and sufficient information, search-based methods can achieve performance comparable or even better than deep learning methods while being computationally efficient. Specifically, the proposed method starts with existing molecules and uses a two-stage search strategy to gradually modify them into new ones, based on transformation rules derived from large compound libraries. We demonstrate all the proposed methods with extensive experiments.
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Title: Toward a Virulent Community Literacy : Constellating the Science, Technology, and Medicine of Queer Sexual Health
Creator: Flores, Wilfredo Antonio
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Toward a Virulent Community Literacy: Constellating the Science, Technology, and Medicine of Queer Sexual Health is a qualitative study (informed by Indigenous and decolonial methodologies) of how queer and trans people of color generate and share knowledge about their sexual health on Twitter with regards to HIV/AIDS. With a Twitter archive of 15,000 discrete tweets built with the keywords “Truvada,” PrEP,” and “HIV,” three datasets were derived comprising general utterances from queer users...
Show moreToward a Virulent Community Literacy: Constellating the Science, Technology, and Medicine of Queer Sexual Health is a qualitative study (informed by Indigenous and decolonial methodologies) of how queer and trans people of color generate and share knowledge about their sexual health on Twitter with regards to HIV/AIDS. With a Twitter archive of 15,000 discrete tweets built with the keywords “Truvada,” PrEP,” and “HIV,” three datasets were derived comprising general utterances from queer users of color, public health officials using social media for outreach, and organizations sharing research findings. Focusing on the data subset comprising 300 discrete users of color and relevant media (i.e., news articles, public health advertisements, other emergent artifacts from the data), this dissertation recounts three case studies focusing on: the rollout of HIV prevention advertisements within queer-centered media; the patent breaking of Truvada, a once-daily medication for preventing HIV; and the use of social media to take to task bad actors and misinformed healthcare providers. The data are used as part of an argument that the manner by which medicine and public health interface with queer and trans people of color hinges on ongoing colonization via the medical and outreach practices derived from colonial practices. Moreover, using a theoretical argument derived from Black and Native technology studies (as well as Black Feminist Thought, Anishinaabe cosmology, settler colonial studies, and digital rhetorical theory), the data was reviewed through a protocol for understanding identity construction amid technology use. The results revealed three rhetorical strategies: 1) continuing community-born public health practices created during the HIV/AIDS crisis of the 1980s and 90s by deploying descriptive hashtags to challenge stigma; 2) creating emergent whisper networks for sharing information about dealing with healthcare providers, navigating insurance networks, and communicating the symptoms of taking the medication; and 3) recognizing and countering the complex systems of late capitalist biomedicalization that prioritize profit over life. To contribute to ongoing commitments within writing and rhetoric studies to create equitable healthcare experiences, an HIV/AIDS health literacy framework follows the data results, which allows for outreach in non-clinical settings through relational design, or a participatory communication design process that incorporates community voices via an attunement to social media such as Twitter. This dissertation contributes to ongoing incursions within technical and professional communication, as well as the rhetoric of health and medicine, to upcycle disciplinary savvy into building better public health and clinical experiences for queer and trans people of color.
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Title: ECOPHYSIOLOGY OF (PERI)ORAL BACTERIA AND IMPACT OF OTIC COLONIZATION
Creator: Jacob, Kristin Marie
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The middle ear is typically assumed to be sterile in health due to its secluded location, closed off from external forces by the tympanic membrane (ear drum) and from the naso/oropharynx by a collapsed Eustachian tube. However, the periodic opening of the Eustachian tube to the naso/oropharyngeal space, which releases pressure across the eardrum and drains otic fluids, could introduce bacteria. Previous studies have tested for the presence of bacteria in the uninfected otic cavity using...
Show moreThe middle ear is typically assumed to be sterile in health due to its secluded location, closed off from external forces by the tympanic membrane (ear drum) and from the naso/oropharynx by a collapsed Eustachian tube. However, the periodic opening of the Eustachian tube to the naso/oropharyngeal space, which releases pressure across the eardrum and drains otic fluids, could introduce bacteria. Previous studies have tested for the presence of bacteria in the uninfected otic cavity using samples collected via invasive surgeries (through or around the eardrum). Findings from these studies are controversial due to contradictory results between studies, lack of critical experimental controls, and sampling of participants with underlying ailments (i.e., cochlear implant surgery) that could impact the microbiology of the otic mucosa. The studies reported herein bypass these limitations by using samples of otic secretions collectively non-invasively (through the mouth) in a cohort of healthy young adults. This dissertation describes cultivation-dependent methods to investigate the microbiology of the middle ear in health. The study used an IRB-approved protocol (#17-502) to collect otic secretions in order to 1) sequence their microbiome (contribution by Dr. Joo-Young Lee) and 2) recover in pure culture otic bacteria for further characterization (my contribution). As controls, we also collected buccal (top palate and inside of cheeks) and oropharyngeal swabs from each participant. Of the collected secretions, samples from 19 individuals were used for culture independent studies, while samples from the remaining 3 participants were subjected to culture dependent studies. 16S rRNA-V4 sequencing detected a diverse and distinct microbiome in otic secretions comprised primarily of strictly anaerobic bacteria belonging to the phyla Bacteroidetes, Firmicutes and Fusobacteria, and to a lesser extent facultative anaerobes (Streptococcus). I recovered from the otic, oropharyngeal, and buccal secretions 39 isolates of predominantly facultative anaerobes belonging to Firmicutes (Streptococcus and Staphylococcus), Actinobacteria (Micrococcus and Corynebacterium), and Proteobacteria (Neisseria) phyla, and used partial 16S rRNA amplicon sequences to demonstrate the distinct phylogenetic placement of otic streptococci compared to the oral ancestors (Chapter 2). This finding is consistent with the ecological diversification of oral streptococci once in the middle ear microenvironment. The recovery of streptococci and transient migrants (Staphylococcus, Neisseria, Micrococcus and Corynebacterium) from otic secretions prompted us to study the adaptive responses that give the streptococcal migrants a competitive advantage during the colonization of the middle ear (Chapter 3). For these studies, I sequenced and partially assembled the genomes of the otic isolates and used the full length 16S rRNA sequences for taxonomic demarcation at the species levels. Phylogenetic analyses demonstrated the oral ancestry of the otic streptococci, which retained from the otic adaptive traits critical for growth and reproduction in the middle ear mucosa (biofilm formation, mucolytic and proteolytic activity, robust growth under redox fluctuations, and fermentative production of lactate, a key metabolic intermediate in the otic trophic webs). These adaptive traits give oral streptococci a colonization advantage over competing (peri)oral migrants such as Staphylococcus. Furthermore, the otic streptococci inhibited the growth of otopathogens, including Staphylococcus aureus. These antagonistic interactions give streptococci a competitive advantage during the colonization of the middle ear and suggest a role for these commensals in promoting mucosal health. The ability of staphylococcal migrants to breach the middle ear mucosal barrier and cause infections prompted us to study the environmental factors that facilitate the spreading of staphylococci from the nasal to the middle ear mucosa. Allergies, respiratory maladies (cold, flu), or (peri)oral bacterial infections (sinus, adenoids, tonsils, etc.) lead to inflammation of the Eustachian tube and changes in the rheological properties of the otic mucus that increase the risk of infections. Thus, we examined the spreading of staphylococci on mucus-like viscous surfaces (semisolid agar plates). In Chapter 4, I show that mucins, the mucosal glycoproteins that control the viscosity and wettability of the mucus layer, induce the rapid spreading and dendritic expansion of clinical isolates closely related to S. aureus and Staphylococcus epidermidis but not of Staphylococcus hominis. Mucin glycosylation controlled the hydration of the mucoid surface and the ability of the cells to spread rapidly, in a process that was dependent on the secretion of surfactant-active, phenol-soluble modulins via the agr-quorum sensing two-component system. These results provide a plausible explanation for the rapid spreading of staphylococcal otopathogens from the nasopharynx to the middle ear through a swollen, and mucin-rich Eustachian tube. The work described in this dissertation provides much needed understanding of the adaptive responses that allow (peri)oral bacteria to colonize the middle ear. The studies add to the accumulating evidence that the middle ear mucosa is not sterile but rather harbors a commensal microbiota in health. These commensal community shares many metabolic similarities with ancestors in oral biofilms and retain adaptive traits critical for growth in the otic mucosa and inhibition of otopathogens. Additionally, this work identifies environmental factors that could contribute to staphylococcal virulence, broadening the understanding of newly identified motility phenotypes in the genus that could provide novel pharmaceutical targets.
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Title: Assessing Safety Performance of Roadway Characteristics in Rural and Urban Contexts
Creator: Chakraborty, Meghna
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Evaluating the safety performance of roadway segments and intersections typically involves associating traffic crashes, injuries, and fatalities to various roadway and traffic characteristics, which typically vary broadly between rural and urban contexts. In rural areas, roadway geometric characteristics often play a critical role in the safety performance of a given roadway, while myriad other factors, including driveways and intersections, tend to have a greater influence on urban roadway...
Show moreEvaluating the safety performance of roadway segments and intersections typically involves associating traffic crashes, injuries, and fatalities to various roadway and traffic characteristics, which typically vary broadly between rural and urban contexts. In rural areas, roadway geometric characteristics often play a critical role in the safety performance of a given roadway, while myriad other factors, including driveways and intersections, tend to have a greater influence on urban roadway safety. However, certain geometric aspects, such as the characteristics of the horizontal curvature and the impact of driveway land-use type have not been well-explored in prior roadway safety research. There has also been limited research on the safety performance for roadways of lower functional classifications, such as minor arterial and collector roadways, which comprise a substantial portion of the nationwide roadway network but are often designed to lower standards and possess driver and trip characteristics that typically differ from those of principal arterials. Therefore, assumptions made on the general effect of the predictor variables from typical safety performance functions may not apply to lower roadway classes. This research sought to explore those gaps in the roadway safety research domain. To accomplish this objective, roadway characteristics were collected along with traffic volume and crash data for greater than 13,000 miles of two-lane roadways in rural, urban, and suburban areas from across the state of Michigan for the period of 2011 through 2018. A series of safety performance functions were developed using a mixed-effects negative binomial modeling structure, which included fixed-effects and random-effects to account for the unobserved heterogeneity associated with varying design standards and site characteristics. The results indicated that driveway density significantly influences crash occurrence across all land-use categories for paved highways, although no impact was observed on unpaved roads. Commercial driveways possessed a stronger effect on crash occurrence than residential driveways or industrial driveways. In urban areas, posted speed limit had a significant positive association with crash frequency, and this effect increased when the speed limit exceeded 40 mph. The effect of speed limit was stronger on urban minor arterial segments (compared to collectors) and for fatal and injury crashes (compared to property damage only). This research also assessed the safety impacts associated with horizontal curve characteristics on rural highway segments, including curve type, curve direction, curve-approaching, curve-following, and inner-curve tangent distances, and curve design speed on rural two-lane undivided highways. Similar to prior research, curves with design speeds lower than the posted speed limit showed elevated crash occurrence. Most notably, compound and reverse curves were associated with greater crash occurrence compared to simple curves, with the greatest impact by the reverse curves. The increased approaching tangent distance for the simple curve or the first of a series of compound or reverse curves increased crash likelihood, perhaps due to the decreased driver expectancy for curvature with increasing tangent distance. However, increased inner-curve tangent distance was found to be associated with decreased crash occurrence. Lastly, the left-turning curves were found to be associated with greater crash occurrence than that on the right-turning curves.
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Title: COBALT REDOX MEDIATORS FOR DYE-SENSITIZED SOLAR CELLS
Creator: Raithel, Austin L.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Dye-sensitized solar cells have become an affordable alternative to conventional photovoltaics.Their efficiencies have become competitive by continued optimization of the semiconductor, dye, redox shuttle, and counter electrode. This thesis will evaluate low-spin Co(II) redox shuttles’ ability to minimize photovoltage losses due to dye regeneration and recombination to semiconductor electrons. Their synthesis and properties will be described along with a comparison to typical high-spin Co(II)...
Show moreDye-sensitized solar cells have become an affordable alternative to conventional photovoltaics.Their efficiencies have become competitive by continued optimization of the semiconductor, dye, redox shuttle, and counter electrode. This thesis will evaluate low-spin Co(II) redox shuttles’ ability to minimize photovoltage losses due to dye regeneration and recombination to semiconductor electrons. Their synthesis and properties will be described along with a comparison to typical high-spin Co(II) redox shuttles. The kinetic properties will be evaluated in terms of Marcus Theory with a particular focus being made on reorganization energy and free energy of electron transfer events. Chapter 1 will describe the motivation for dye-sensitized solar cells along with a description of their development and operation. Chapter 2 and 3 will describe the two extremes of redox potential of the redox shuttle. Chapter 4 demonstrates a system with a tunable potential inbetween. Chapter 5 will report other redox shuttle candidates and future directions to surpass 15% power conversion efficiency with low-spin Co(II) redox shuttles.
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Title: CONTRIBUTIONS TO EPIDEMIOLOGICAL RESEARCH ON THE SELLING OF INTERNATIONALLY REGULATED DRUGS
Creator: Yuan, Sha
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The existing research on drug selling among teenagers is limited. A few research teams have studied aspects of adolescent drug dealing. The scope of research includes economic factors relaed to youths involved in drug gangs (Levitt & Venkatesh, 2000) as well as psychosocial factors that might prompt teenagers to sell drugs (Fagan J, 1990; Little & Steinberg, 2006). Few have thought about adolescent drug selling from an epidemiological perspective, with a conceptualization based on agent-host...
Show moreThe existing research on drug selling among teenagers is limited. A few research teams have studied aspects of adolescent drug dealing. The scope of research includes economic factors relaed to youths involved in drug gangs (Levitt & Venkatesh, 2000) as well as psychosocial factors that might prompt teenagers to sell drugs (Fagan J, 1990; Little & Steinberg, 2006). Few have thought about adolescent drug selling from an epidemiological perspective, with a conceptualization based on agent-host-environment triad models, and with attention to potential public health control methods required for effective interventions.An early contributor, Isidore Chein and his research team (1964) launched important psychosocial research on youthful drug selling. According to that research, adolescents involved in heroin use often conducted drug dealing. However, the samples were limited to male adolescents in New York City, and the data collection period was from 1949 to 1955. This doctoral dissertation research project builds upon progress made by Chein and his colleagues. It summarizes a set of studies of youthful drug selling that merit attention. The project then aims to contribute new epidemiological findings on adolescents selling internationally regulated drugs (IRD) such as cannabis and cocaine. From an epidemiologist’s point of view, a drug seller can be considered a vector in the person-to-person spread of drug involvement. For this reason, a comprehensive view of the epidemiology of drug involvement should not neglect drug selling. For this dissertation research project, I conducted four investigations with focus on the drug onset and drug selling experiences of 12-to-17-year-old adolescents in the United States community populations. The first investigation aims to estimate the age-specific prevalence of recent drug selling behaviors for the age period of 12 to 17 years, with attention to the following subgroups that Salas-Wright and colleagues (2017) recently identified as having a higher prevalence of drug selling in the non-institutionalized U.S. population: (a) males and (b) older adolescents. The second study aims to produce estimates concerning birth cohort variations in drug selling prevalence. The third study divides youths into three groups: “never used any IRD” group, “cannabis only at first IRD use” group, and “used a non-cannabis IRD with or without concurrent cannabis use at first IRD use” group. The investigation then turns to an estimation of the likelihood of being a seller of drugs in the past 12 months for each of these three groups, with attention to the duration of IRD use, The fourth study aims to compare non-users and users whose first drug is cannabis with respect to their odds of selling drugs in the second year after first drug use. The population under study was sampled for annual United States National Surveys of Drug Use and Health (NSDUH). The NSDUH sampled, recruited, and assessed non-institutionalized US civilian residents aged 12 and above each year. After Institutional Review Board-approved consent procedures, all participants were assessed using confidential audio computer-assisted self-interviews. There are cannabis and youth experience modules and modules on other drugs and health topics in the self-interview sessions. The findings of all the four studies in this dissertation are from statistical analyses of NSDUH public-use data files based on the survey questions in the aforementioned modules. The main findings and implications, summarized across the four research projects, are as follows: • Study 1: The estimated prevalence of drug selling increases with age during the adolescent years under study. The estimated prevalence for boys is larger than the corresponding estimates for girls. • Study 2: Estimated age-specific prevalence patterns do not vary appreciably across recent birth cohorts. The general pattern is one of cohort-specific increases in the odds of drug-selling from age 12 to age 17; estimates of 17-year olds are larger. • Study 3: Starting to use cannabis and no other IRD is associated with greater odds of drug selling in the subsequent adolescent years. The study estimates suggest that as time passes since first IRD use, the odds of drug selling increase (up to a point). If the first IRD use is not cannabis, then the estimated odds of drug selling may be larger than if cannabis is the only IRD that has been used. • Study 4: Adolescents who start to use cannabis but none of the other internationally regulated drugs are observed to be more likely to sell drugs in the second year after the first use, compared to adolescents who have never used any drug. Subject to limitations described in this dissertation report, these findings merit further investigation and attention in public health initiatives to prevent the person-to-person spread of drug use during adolescence. The dissertation research report also describes some future research directions that can build upon this project’s findings, which include future longitudinal and prospective investigations.
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Title: Quantum coherent transport phenomena in epitaxial halide perovskite thin films
Creator: Zhang, Liangji
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The subject of this dissertation is the experimental study of quantum coherent transport phenomena in epitaxial single-crystal halide perovskite thin films. The experiments consist of low-temperature (down to 10 mK) magnetotransport measurements at high magnetic field (up to 14 T).The recent advent of epitaxial thin film growth of inorganic halide perovskites has made it possible to investigate the quantum behavior of charge carriers in these materials in low-dimensional form. We present...
Show moreThe subject of this dissertation is the experimental study of quantum coherent transport phenomena in epitaxial single-crystal halide perovskite thin films. The experiments consist of low-temperature (down to 10 mK) magnetotransport measurements at high magnetic field (up to 14 T).The recent advent of epitaxial thin film growth of inorganic halide perovskites has made it possible to investigate the quantum behavior of charge carriers in these materials in low-dimensional form. We present results on epitaxial single-domain cesium tin iodide (CsSnI3) thin films that clearly demonstrate quantum transport in this material for the first time. The observed low-field magnetoresistance shows signatures of weak anti-localization (WAL) that reveals coherent quantum interference effects and spin-orbit coupling. A micron-scale (≈5 um) low-temperature phase coherence length for charge carriers in the system is extracted from these WAL measurements.Additionally, we present low-temperature quantum magnetotransport measurements on thin film devices made of epitaxial single-crystal CsSnBr3, which exhibit two-dimensional Mott variable range hopping (VRH) and a large negative magnetoresistance. These findings are described by the Nguyen-Spivak-Shkovskii (NSS) model for quantum interference between different directed hopping paths, and we extract the temperature-dependent hopping length of charge carriers, their localization length, and a lower bound for their phase coherence length of ~100 nm at low temperatures. These results from CsSnI3 and CsSnBr3 devices demonstrate that epitaxial halide perovskite devices are emerging as a material class for low-dimensional quantum coherent transport devices.In addition to the works that are described above, I have also been involved in several additional projects, such as experiments on low-dimensional electron systems and superconducting qubit experiments, which will not be described in this dissertation.
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Title: PUBERTAL DIFFERENCES IN THE EFFECTS OF PARENTING ON BINGE EATING RISK IN FEMALE PRE-ADOLESCENTS AND ADOLESCENTS
Creator: Anaya Maldonado, Carolina
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Puberty is a period of increased risk for the development of binge eating in female adolescents. Studies thus far have examined changes in genetic factors and personality characteristics that could contribute to increased risk, but none have examined parenting practices that are known to change across development and significantly contribute to youth outcomes (e.g., parent-child conflict, parental warmth, parental overprotection). The current study examines whether interactions between...
Show morePuberty is a period of increased risk for the development of binge eating in female adolescents. Studies thus far have examined changes in genetic factors and personality characteristics that could contribute to increased risk, but none have examined parenting practices that are known to change across development and significantly contribute to youth outcomes (e.g., parent-child conflict, parental warmth, parental overprotection). The current study examines whether interactions between puberty and parenting predict higher levels of binge eating symptoms during/after puberty in female youth. Analyses used cross-sectional data in a sample of 999 female youth (ages 8-16) and their parents from the Michigan State University Twin Registry. Youth provided ratings of binge eating, eating in the absence of hunger, emotional eating, perceived parental care and overprotection. and pubertal development. Both youth and parents provided ratings of parent-child conflict. Although higher levels of parental overprotection and conflict, and lower levels of parental care, significantly predicted all binge eating measures, none of the associations were significantly moderated by pubertal development or age. The quality of the parent-child relationship is significantly associated with binge eating in female pre-adolescents and adolescents regardless of developmental stage, highlighting the need for targeting harmful parenting strategies during adolescent eating disorder intervention.
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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: DESIGNING DECLINE : THE RECLAMATION OF AN INDUSTRIAL SITE AND THE DESIGN IMPACTS ON ENVIRONMENTAL, SOCIAL AND ECONOMIC RESILIENCE
Creator: Shevela, Brooke
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The abandoned industrial crisis in Michigan, USA calls for the redevelopment of abandoned industrial site areas into functioning public spaces. These neglected spaces develop negative impacts on the surrounding communities regarding aesthetic, safety, economic, and environmental issues. The purpose of this study is to examine the redevelopment of an underused site, especially featuring an industrial site element, and the effects on the nearby community by applying quantitative measures. The...
Show moreThe abandoned industrial crisis in Michigan, USA calls for the redevelopment of abandoned industrial site areas into functioning public spaces. These neglected spaces develop negative impacts on the surrounding communities regarding aesthetic, safety, economic, and environmental issues. The purpose of this study is to examine the redevelopment of an underused site, especially featuring an industrial site element, and the effects on the nearby community by applying quantitative measures. The Michigan Central Station in Detroit, Michigan, USA was selected as a case study. Landscape performance research was applied to quantitively analyze the environmental, social and economic benefits of reclaiming abandoned industrial sites and their inner elements. In this research, findings showed the case study redesign resulted in positive environmental impacts. These impacts included: expanded areas of ecologically valuable land, increases in carbon sequestration, increases in retained stormwater, the use of recycled content and reductions in sulfur dioxide. The case study redevelopment showed impacts on the surrounding economics through savings on water treatment cost through stormwater retention, increases in property values, and job creation. Furthermore, the redesign also impacted social aspects for the surrounding areas including increases in the area of proposed gathering space, safety enhancements, additions of sidewalks and bike lanes, and increases in the area of public open space. In addition, the major findings support the benefits of public physical health by promoting outdoor activities. The findings of this study will help designers and urban planners to see the value in reusing existing industrial sites instead of undergoing the harmful demolition process and eventually lead to a more sustainable community design.
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Title: Teaching Presence in a Fully Online Asynchronous Undergraduate Mathematics Course and its Impact on Social and Cognitive Presence
Creator: Elmore, Robert Andrew
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The number of fully online asynchronous undergraduate mathematics courses is growing rapidly, making it imperative that the instructional choices that are chosen by instructors and their effects on students’ opportunities to learn in the online learning environment be further explored. Therefore, this research aims to understand instructors' choices when teaching an online undergraduate mathematics course, and how these decisions impact students' communication opportunities. This research...
Show moreThe number of fully online asynchronous undergraduate mathematics courses is growing rapidly, making it imperative that the instructional choices that are chosen by instructors and their effects on students’ opportunities to learn in the online learning environment be further explored. Therefore, this research aims to understand instructors' choices when teaching an online undergraduate mathematics course, and how these decisions impact students' communication opportunities. This research organized the instructors' decisions and their impacts on students using the community of inquiry framework. The three categories of the community of inquiry framework, teaching presence, social presence, and cognitive presence, were analyzed through course artifacts, an instructor interview, student interviews, student surveys, and course usage data. The primary analysis was performed using the interviews with the other data sources providing further detail and explanation. Four claims were generated while analyzing these data sources. Claim one posits that students tend to have singular preferences of the course’s direct instructional elements. Claim 2 proffers that students who chose to work with others report having positive experiences, and those who decided not to work with others report not needing help, with one exception. Claim 3 states that meaningful contact points can be created between the instructor and student using surveys and personalized mass emails; however, most describe learning mathematics in Math 101 as not making them feel a part of a learning community. And claim 4 posits that elements of the teaching presence were more likely to foster participation if they were associated with a grade. The results of this study have implications for both the research and practice communities. The current study’s results imply that—even though sizes of online mathematics classes may still grow—there are ways instructors can facilitate high levels of social processes using mass email, surveys, cooperative learning groups, and other online tools. These specific tools should be studied and evaluated for their effects on social presence and cognitive presence on the mass scale. The present study suggests four specific things that instructors should familiarize themselves with that are available today, (a) prescribe opportunities for students to communicate with each other such as having assignments that are completed in cooperative learning groups, (b) communicate with your students through personalized means (e.g., emails, surveys, and Zoom sessions), (c) use feedback from surveys to inform your future teaching practice, and (d) ensure that students observe your communication and direct instruction by tying them to elements associated with grades. Keywords: teaching presence, social presence, cognitive presence, online mathematics learning.
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Title: DO INTERFACES MATTER? A REEXAMINATION OF XBRL USING FINANCIAL STATEMENT ACQUISITION AND MARKET ACTIVITY
Creator: Anderson, James J.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Starting in 2009 the eXtensible Business Reporting Language (XBRL) standard was mandated for financial statements by the SEC. The XBRL standard was intended to encourage less-sophisticated trader disclosure processing; however, previous literature has conjectured that the standard primarily aided more-sophisticated traders’ disclosure processing. I reexamine the effect of XBRL on more- and less-sophisticated trader disclosure processing by testing whether XBRL influenced their information...
Show moreStarting in 2009 the eXtensible Business Reporting Language (XBRL) standard was mandated for financial statements by the SEC. The XBRL standard was intended to encourage less-sophisticated trader disclosure processing; however, previous literature has conjectured that the standard primarily aided more-sophisticated traders’ disclosure processing. I reexamine the effect of XBRL on more- and less-sophisticated trader disclosure processing by testing whether XBRL influenced their information acquisition and testing whether the proportional relationship between information acquisition and market activity is different for more- and less-sophisticated traders. I find the staggered implementation of XBRL is associated with a 49% (26%) increase in less (more) sophisticated trader information acquisition. Next, I find the proportional relationship between information acquisition and market activity is greater for less-sophisticated traders when compared to more-sophisticated traders. Specifically, I find information acquisition for less-sophisticated traders has a greater proportional relationship with abnormal price movement, abnormal trading volume, and abnormal bid-ask spreads. Together these findings suggest that XBRL did not provide a disproportionate information advantage to more-sophisticated traders, but rather benefited less-sophisticated traders by decreasing their information acquisition costs.
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Title: QUALITY OF LIFE IN CONTEMPORARY NEIGHBORHOOD DESIGN INITIATIVES : AN EMPIRICAL STUDY TO ASSESS QUALITY OF LIFE THROUGH SPATIAL DIMENSION IN NEW URBANIST AND LEED-ND CERTIFIED NEIGHBORHOODS
Creator: Shaaban, Amal Hamdy
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The overarching purpose of this study is to analyze qualitatively and quantitatively the spatial characteristics of two types of neighborhoods, namely New Urbanist (NU) neighborhoods and Leadership in Energy and Environmental Design (LEED) certified neighborhoods. LEED certified neighborhoods are commonly referred to as LEED for Neighborhood Development (LEED-ND). In this research study, the spatial quality of these two types of neighborhoods was examined through assessing the quality of five...
Show moreThe overarching purpose of this study is to analyze qualitatively and quantitatively the spatial characteristics of two types of neighborhoods, namely New Urbanist (NU) neighborhoods and Leadership in Energy and Environmental Design (LEED) certified neighborhoods. LEED certified neighborhoods are commonly referred to as LEED for Neighborhood Development (LEED-ND). In this research study, the spatial quality of these two types of neighborhoods was examined through assessing the quality of five dimensions of a neighborhood’s urban form, which are: safety, comfort, connectivity, place making and aesthetic quality. Three types of neighborhoods were selected and examined using two main analytical tools: neighborhood scorecard, and residents’ survey. Two neighborhoods were selected to examine NU neighborhoods in Michigan in the United States, which are Cherry Hill Village (CHV) a greenfield residential development, and Mason Run (MR) a brownfield residential development. The third neighborhood was selected to examine LEED-ND certified neighborhoods, which is Saint Luke (SL) neighborhood in Ohio in the United States. The neighborhood scorecard included a total of 150 design guidelines that yield better Quality of Life (QoL) in residential developments through urban form. The residents’ survey included a set of questions that examined the residents’ perceptions regarding the five physical characteristics necessary to yield better QoL. A total of 154 surveys were collected for data analysis that used one-way ANOVA tests, Tukey’s post-hoc tests, and multiple regression models. The major findings from the neighborhood scorecard are that CHV neighborhood provides was safer than the brownfield NU residential development and the LEED-ND certified neighborhood. Both NU neighborhoods provided more comfortable environments of their residents to live in more than the LEED-ND certified neighborhood. The greenfield NU neighborhood earned more points than the other two neighborhoods in terms of the internal and external connectivity degree of the neighborhood. In terms of fulfilling the recommended design guidelines for place making and aesthetic quality, again the Greenfield NU neighborhood had earned higher points than the other two neighborhoods. The major findings from the survey are: Survey participants living in both NU neighborhoods were more satisfied with their QoL more than the participants living in the LEED-ND certified neighborhood. Also, respondents living in NU neighborhoods perceived their neighborhoods as safer places to live in more than participants living in the LEED-ND certified neighborhood. On the other hand, respondents living in the NU brownfield development perceived their neighborhood as the least comfortable neighborhood. In terms of the internal connectivity of the neighborhood, respondents living in NU greenfield development identified the internal connectivity of their neighborhood as the highest compared to the other two neighborhoods. On the other hand, the perception of the internal connectivity perception was the lowest amongst respondents living in the LEED-ND certified neighborhood. Respondents living in the LEED-ND certified neighborhood had the highest mean in terms of their perceptions of sense of belonging. On the other hand, respondents living in the NU brownfield development had the lowest mean in terms of their perception of sense of belonging. The perception of the aesthetic quality of the neighborhood was the highest among respondents living in the NU greenfield development. On the other hand, the perception of aesthetic quality of the neighborhood was the least among respondents living in NU brownfield development.This research study concludes by suggesting recommendations to improve the principles and design guidelines of NU and LEED-ND certified neighborhoods to achieve better QoL. The recommendations suggest emphasizing certain spatial characteristics that yield better QoL in Greenfield, and brownfield residential developments.
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Title: Mechanisms underlying Binocular Rivalry
Creator: Jagtap, Abhilasha R.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: When observers view a perceptually bistable stimulus, their perception changes stochastically. Various studies have shown across-observer correlations in the percept durations for different bistable stimuli including Necker cube, binocular rivalry (BR) and bistable moving plaids (MP), which suggests a shared mechanism underlying perception in these paradigms. In this project we explore such shared mechanisms by examining what determines whether a given set of bistable perception paradigms...
Show moreWhen observers view a perceptually bistable stimulus, their perception changes stochastically. Various studies have shown across-observer correlations in the percept durations for different bistable stimuli including Necker cube, binocular rivalry (BR) and bistable moving plaids (MP), which suggests a shared mechanism underlying perception in these paradigms. In this project we explore such shared mechanisms by examining what determines whether a given set of bistable perception paradigms will exhibit correlations in percept durations, and also by examining correlations with other perceptual phenomena that do not directly involve bistability. In our first experiment, we hypothesize that the presence or absence of a certain type of motion can influence whether different bistable paradigms will exhibit correlated percept durations. We found that the correlations between some bistable stimuli are strong, but others are fragile and inconsistent, which prevents us from drawing direct conclusions. In the second experiment, we examine whether between-observer variability in cortical inhibition underlies correlated percept durations between binocular rivalry and bistable moving plaid perception. As a behavioral measure of cortical inhibition, we used center-surround suppression of perceived contrast. While we were able to successfully replicate the correlations between bistable paradigms, there was no correlation between center-surround suppression strength and percept durations for any bistable paradigm. Moreover, the results from a mediation analysis indicate that center-surround suppression is not the mediating factor in the correlation between BR and MP, suggesting that cortical inhibition cannot explain the correlation between various bistable paradigms.
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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: 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: MENTAL HEALTH AND THE URBAN ENVIRONMENT : A BIBLIOMETRIC MAPPING OF KNOWLEDGE STRUCTURE AND TRENDS
Creator: Van Winkle, Taylor
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The literature on the urban environment, health, and well-being has steadily increased over the last decade. This paper aims to offer a better understanding of the state of the literature on assessing the urban environment and health through mapping the field of research through a scoping review and illuminating emerging trends and future research using keyword frequency and bibliometric analysis. Uniquely, this study drew 495 articles from four distinct journal databases (PubMed, Scopus, Web...
Show moreThe literature on the urban environment, health, and well-being has steadily increased over the last decade. This paper aims to offer a better understanding of the state of the literature on assessing the urban environment and health through mapping the field of research through a scoping review and illuminating emerging trends and future research using keyword frequency and bibliometric analysis. Uniquely, this study drew 495 articles from four distinct journal databases (PubMed, Scopus, Web of Science, and ProQuest), whereas traditional bibliometric analyses draw from a single source. By drawing from a broader base of knowledge, this study offers a more holistic view of the trends in the field of research on the connection between urban environments and well-being to better identify future research pathways. The results show trends of a consistent increase in research on the topic over the last decade. Research published on this topic is fragmented, with consistent but isolated focus on physical health, mental health, and environmental characteristics. Overall, in this field, physical health is most often assessed in relationship to the urban built environment, while mental health is most often assessed in connection to the urban natural environment. This paper also provides information on influential authors in this field of research. This study concludes by highlighting gaps and making recommendations for future research in the field. Prominent gaps are related to using interdisciplinary and scalable approaches to understanding the relationship between urban environments and overall well-being.
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Title: TEMPORAL LINKAGES BETWEEN NEARSHORE BATHYMETRY, SHORE ICE MORPHOLOGY, AND GEOMORPHIC CHANGE ALONG A COLD-CLIMATE COASTLINE
Creator: Hartley, Brittany M.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: The nearshore ice complex (NIC) though previously studied, has given researchers muddled conclusions when studies are compared, as the documented morphological response to ice presence has been varied. This blurriness of understanding promoted the opportunity for research, and with the availability of new and improved technology, an opportunity for high accuracy analysis also arises. This study showed that ice ridge location corresponded to the bar and trough system in lakebed morphology,...
Show moreThe nearshore ice complex (NIC) though previously studied, has given researchers muddled conclusions when studies are compared, as the documented morphological response to ice presence has been varied. This blurriness of understanding promoted the opportunity for research, and with the availability of new and improved technology, an opportunity for high accuracy analysis also arises. This study showed that ice ridge location corresponded to the bar and trough system in lakebed morphology, rather than just a nearshore bar or trough. Along with that, the ice presence lowered the overall elevation of the lakebed profile, and this promoted erosion throughout the remainder of the study period. During the entirety of the research study period, the most change that was documented was found between August and November 2020 due to a large, recoded storm event that moved through the study location.
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Title: THE EFFECTS OF MEDIUM AND LARGE-SCALE FARMS ON YOUNG PEOPLE’S EMPLOYMENT IN AGRICULTURE : EVIDENCE FROM TANZANIA
Creator: Samboko, Paul C.
Date: 2022
Collection: Electronic Theses & Dissertations
Description: There is limited empirical evidence on how the growth of large- and medium-scale farms is affecting employment outcomes across the whole agricultural sector in developing countries, and especially among young people (age 15-35 years). A priori, it is impossible to determine how medium- and large-scale farms affect employment for young people in agriculture. Using employment data for young people in Tanzania, this study examines whether increases in the region-level share of cropping...
Show moreThere is limited empirical evidence on how the growth of large- and medium-scale farms is affecting employment outcomes across the whole agricultural sector in developing countries, and especially among young people (age 15-35 years). A priori, it is impossible to determine how medium- and large-scale farms affect employment for young people in agriculture. Using employment data for young people in Tanzania, this study examines whether increases in the region-level share of cropping households that are medium- and large-scale farms (MLSFs) improve or worsen agricultural employment outcomes for young people. The outcomes include: (i) employment in crop/livestock production on own farm; (ii) self-employment in agribusiness activities and (iv) employment in agriculture via any of the first three categories above.Correlated random effects probit model results suggest that the growth of medium-scale farms is associated with reductions in the participation of young people in the production of crops/livestock on their own or their family’s farms. It is also associated with a reduction in the employment of young people in the agricultural sector overall. The growth of large-scale farms is associated with an increase in self-employment in agriculture by young people. The government needs to be cognizant of the effects of different farm sizes on employment. Medium-scale farms may not be an avenue to improve young people’s involvement in agriculture. However, large-scale farm expansion may improve young adult’s employment in agricultural employment
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Title: The Impact of Multiple Forms of Discrimination on Mental Health in Transgender and Gender Diverse People
Creator: Glozier, Kalei
Date: 2022
Collection: Electronic Theses & Dissertations
Description: Transgender and gender diverse (TGD) people experience a variety of stressors, one of which being discrimination. These experiences of discrimination are embedded within power structures that privilege cisgender, white, heterosexual individuals, and those with other dominant identities and result in the marginalization of those outside of those identities across a multitude of contexts. This study examines experiences of discrimination in a sample of 158 TGD individuals and the relationship...
Show moreTransgender and gender diverse (TGD) people experience a variety of stressors, one of which being discrimination. These experiences of discrimination are embedded within power structures that privilege cisgender, white, heterosexual individuals, and those with other dominant identities and result in the marginalization of those outside of those identities across a multitude of contexts. This study examines experiences of discrimination in a sample of 158 TGD individuals and the relationship between discrimination, mental health, and social disadvantage. The current study used latent class analysis (LCA) to separate participants into classes based on their experiences of discrimination based on their identities: Class 1 (All Types)- had the highest probability of endorsing all types of discrimination experiences, Class 2 (Few Types)- had a low probability of endorsing discrimination experiences based on their identity, and Class 3 (SGM Types)- had a high probability of endorsing discrimination experiences related to gender identity, gender presentation, and sexuality, but a low probability of endorsing discrimination based on race and ancestry. Class membership did not significantly predict mental health outcomes; however, social disadvantage was a predictor of mental health outcomes. Thus, social disadvantage should be systematically addressed to prevent poor mental health outcomes in TGD populations.
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