Search results

Title: FROM SITTING TO LIVING : EXAMINING THE ROLE OF MEDITATION IN UNDERSTANDING THE EMOTION REGULATORY MECHANISMS OF MINDFULNESS
Creator: Lin, Yanli
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Mindfulness has received widespread interest for its purported benefits to emotional well-being. Despite a rapidly growing literature base supporting the salutary relationship between mindfulness and emotion regulation, little is known about how mindfulness confers its emotion regulatory benefits. A pertinent, yet underexplored, approach to addressing this question is to examine neural mechanisms involved in the effects of mindfulness training via meditative practice to “off-the-cushion”...
Show moreMindfulness has received widespread interest for its purported benefits to emotional well-being. Despite a rapidly growing literature base supporting the salutary relationship between mindfulness and emotion regulation, little is known about how mindfulness confers its emotion regulatory benefits. A pertinent, yet underexplored, approach to addressing this question is to examine neural mechanisms involved in the effects of mindfulness training via meditative practice to “off-the-cushion” changes in emotion regulation. The primary aim of the present study was therefore to determine the extent to which change in neural oscillatory activity (i.e., alpha and theta power) during mindfulness meditation related to subjective (i.e., self-reported negative affect) and neural (i.e., late positive potential [LPP]) measures of emotional reactivity elicited during a subsequent affective picture viewing task. Toward this end, a multimodal experimental paradigm was employed to test three predictions: 1) participants randomized to engage in brief guided mindfulness meditation, relative to those randomized to a control condition, would exhibit increased alpha and theta power during meditation relative to rest; 2) participants in the meditation group, but not those in the control group, would exhibit attenuated LPP responses and report lower negative affect during the picture viewing task; 3) the predicted increases in alpha and theta power during meditation would correlate with the predicted reductions in the LPP and self-reported negative affect during picture viewing. Contrary to expectations, the guided meditation did not produce demonstrable effects on alpha and theta power, the LPP, or self-reported negative affect relative to the control condition. Change in theta, but not alpha, power during meditation was, however, positively correlated with the early time window of the LPP, suggesting that change in neural activity during meditation may relate to subsequent emotion processing. Overall, the study demonstrated the utility of investigating the relationship between what occurs during mindfulness meditation and its purported effects on emotion regulation. Moreover, reflections on the unexpected nature of the null findings dovetail with the prevailing consensus that theoretical and methodological factors unique to the construct of mindfulness are integral in shaping the direction, design, and interpretability of mindfulness research.
Show less

Title: SYSTEMATIC ANALYSIS OF THE SIGNAL RESPONSIVE GENE REGULATORY NETWORK GOVERNING MYXOCOCCUS XANTHUS DEVELOPMENT
Creator: Saha, Shreya
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Studies of signal-induced gene expression in bacteria have contributed to understanding of how bacteria cope with environmental stress. As an extensively studied model, Myxococcus xanthus provides fascinating insights into how changes at the level of gene expression enable which bacteria to survive environmental insults such as nutrient limitation. Upon starvation M. xanthus cells glide into aggregates and form mounds that mature into fruiting bodies as some cells form spores. Previously, our...
Show moreStudies of signal-induced gene expression in bacteria have contributed to understanding of how bacteria cope with environmental stress. As an extensively studied model, Myxococcus xanthus provides fascinating insights into how changes at the level of gene expression enable which bacteria to survive environmental insults such as nutrient limitation. Upon starvation M. xanthus cells glide into aggregates and form mounds that mature into fruiting bodies as some cells form spores. Previously, our group defined 24-30 h poststarvation as the critical period for commitment to spore formation, when cells commit to form spores despite perturbation of the starvation signal by nutrient addition. The process of multicellular development that culminates in sporulation is governed by a network of signal-responsive transcription factors that integrate signals for starvation and cellular alignment. In this dissertation I present the first systematic approach to elucidate the network dynamics during the commitment period.In the network, MrpC is a starvation-responsive transcription factor, whereas FruA is a transcription factor that responds to cellular alignment conveyed by C-signaling. Transcription of fruA is dependent on MrpC binding, and FruA activity is proposed to be posttranslationally regulated by C-signaling, although the mechanism is unknown. FruA and MrpC cooperatively regulate transcription of the dev operon. My systematic analysis of the network dynamics supported a model in which posttranslational activation of FruA by C-signaling is critical for dev transcription and for commitment to spore formation. Similar to dev, MrpC and C-signal-activated FruA combinatorially controlled transcription of the late-acting fadIJ operon involved in spore metabolism. Regulation of late-acting operons implicated in spore coat biogenesis (exoA-I, nfsA-H, MXAN_3259-MXAN_3263) was discovered to be under complex control by MrpC and FruA. My evidence suggests that transcription of these operons depends at least in part on a C-signal-dependent switch from negative regulation by unactivated FruA to positive regulation by activated FruA during the period leading up to and including commitment to sporulation. MrpC negatively regulated exo and MXAN_3259 during mound formation, but positively regulated nfs. During commitment to sporulation, MrpC continued to positively regulate nfs, switched to positive regulation of MXAN_3259, and continued to negatively regulate exo. A third transcription factor, Nla6, appeared to be a positive regulator of all the late genes. We propose that in combination with regulation by Nla6, differential regulation by FruA in response to C-signaling and by MrpC controls late gene expression to ensure that spore resistance and surface characteristics meet environmental demands.
Show less

Title: NEW APPROACHES TO ASSESS AND IMPROVE PROTEIN EFFICIENCY IN LACTATING DAIRY COWS
Creator: Liu, Enhong
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The long-term goal of the work is to improve protein efficiency in lactating dairy cows. To achieve this goal, four specific objectives were proposed: 1) determine the relationship of residual feed intake (RFI) to protein efficiency in lactating Holstein cows fed high or low protein diets, 2) determine whether low protein resilience (LPR) is an indicator of protein efficiency in individual dairy cows, 3) examine the association of digestibility with RFI and LPR in lactating dairy cows, and 4)...
Show moreThe long-term goal of the work is to improve protein efficiency in lactating dairy cows. To achieve this goal, four specific objectives were proposed: 1) determine the relationship of residual feed intake (RFI) to protein efficiency in lactating Holstein cows fed high or low protein diets, 2) determine whether low protein resilience (LPR) is an indicator of protein efficiency in individual dairy cows, 3) examine the association of digestibility with RFI and LPR in lactating dairy cows, and 4) quantify the importance of including body weight (BW) change in the cow response to decreased dietary protein content and develop models for predicting BW change when dietary protein is altered. Lactating Holstein cows (n= 166; 92 primiparous, 77 multiparous) with initial milk yield (MY) of 41 ± 9.8 kg/d were fed high (HP) and low (LP) protein diets in crossover experiments of two 28-35 d periods. Experiments were repeated in 69 of the 166 cows (42 primiparous, 27 multiparous) in late lactation. Low protein diets were 14% CP in peak lactation and 13% CP in late lactation and were formulated to contain adequate rumen-degraded protein to maintain rumen function. Expeller soybean meal was added to formulate the HP diet, which contained 18% CP in peak lactation and 16% CP in late lactation. Cows were milked twice daily; DMI and MY were recorded once daily. Milk composition was measured over 4 consecutive milkings weekly, and BW was measured 3 times weekly. Samples of feed ingredients, orts and feces were collected in the last 5 days of each period and analyzed to determine digestibilities of DM, NDF, and CP for each cow on each diet. Fixed effects of diet, parity, treatment sequence nested in experiment, treatment period nested in experiment, interaction of parity and diet, and random effects of experiment and cow nested within experiment were included in models to compare production of cows fed different levels of CP. Protein efficiency was calculated for each cow on each diet in both peak lactation and late lactation. Residual feed intake was estimated for each cow on each treatment based on the actual intake, milk energy output, metabolic BW, and body energy change (estimated from BW change and BCS). Low protein resilience was estimated for each cow in peak lactation and also late lactation, based on protein captured in milk and body tissue when fed the LP vs HP diet. A negative correlation was observed between RFI and protein efficiency in cows fed the HP and LP diets in peak lactation and cows fed the HP diet in late lactation. Cows with higher LPR values had similar protein efficiency on the HP diet but significantly higher protein efficiency on the LP diet. Neither RFI nor LPR was correlated with digestibility regardless of diets or lactation stages. When dietary protein content was reduced, 40-50 % of the total energy loss, 10-20 % of total protein loss, and 15-25% of total income loss were due to BW loss, indicating that considering only changes in milk production underestimates the impact of dietary protein changes. In conclusion, 1) cows with lower RFI values utilized protein more efficiently, and protein efficiency will be improved in the process of selecting dairy cattle for low RFI, 2) cows with higher LPR values are better able to maintain production and have higher protein efficiency to adapt to low-protein feeding conditions, 3) variation in digestibility cannot explain the variations of RFI or LPR among lactating dairy cows, and we suggest that post-absorptive metabolism explains most of the variation in RFI and LPR when lactating cows are fed diets with minimal NDF in peak lactation and 40% NDF in late lactation, and 4) body reserve mobilization should not be neglected when assessing the cow response to changes in dietary protein.
Show less

Title: Using manipulatives to support secondary students with high-incidence disabilities in algebra
Creator: Bone, Erin
Date: 2020
Collection: Electronic Theses & Dissertations
Description: All students, including students with disabilities, are expected to learn mathematics at high levels. As algebra is considered to be the gatekeeper to higher level mathematics and beyond, it is essential for teachers to use effective practices, including the use of manipulatives, to support student learning. This alternative dissertation is comprised of three studies that explored teaching algebra to secondary students with high-incidence disabilities. The first was an evidence-based...
Show moreAll students, including students with disabilities, are expected to learn mathematics at high levels. As algebra is considered to be the gatekeeper to higher level mathematics and beyond, it is essential for teachers to use effective practices, including the use of manipulatives, to support student learning. This alternative dissertation is comprised of three studies that explored teaching algebra to secondary students with high-incidence disabilities. The first was an evidence-based systematic review of literature investigating instructional practices to teach algebra to secondary students with high-incidence disabilities. Twenty studies published from 1999-2019 were reviewed and analyzed, of which 14 met the standards of high quality set by the Council for Exceptional Children (CEC), and five practices earned the label of potentially evidence-based (i.e., concrete-representational-abstract framework, manipulatives, enhanced anchor instruction, schema based instruction, and peer-assisted learning strategies). The second study used an alternating treatment design to compare the effectiveness of concrete algebra tiles to virtual algebra tiles to support middle school students with disabilities as they solved linear equations. Students were successful solving linear equations regardless of the type of manipulative they used, but preferred using the virtual tool. The final study used a multiple probe across behaviors, replicated across participant design to examine the effectiveness of the VA framework to support secondary students with high-incidence disabilities in their acquisition of algebra skills. A functional relationship existed between the VA framework and student performance on algebra probes, and students scored better on maintenance probes compared to baseline data. While there remains a need for more high-quality research examining effective practices in supporting secondary students with high-incidence disabilities in the area of algebra, the studies in this alternative dissertation suggest manipulatives, both as a stand-alone tool and as part of a process is an effective, and efficient intervention.
Show less

Title: Antiracist teacher education and whiteness : towards a collective humanization
Creator: Moore, Ashley E.
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Using Critical Whiteness Studies (CWS) as theoretical grounding, this three-article dissertation offers perspectives on antiracist teacher education praxis, and the ways that White teacher educators can be more thoughtful and critical of our participation in perpetuating Whiteness. Across the articles, I explore how my attempts to embody antiracist praxis as a White teacher educator are still fraught with performances of Whiteness.In the first article, I use interviews from student-nominated...
Show moreUsing Critical Whiteness Studies (CWS) as theoretical grounding, this three-article dissertation offers perspectives on antiracist teacher education praxis, and the ways that White teacher educators can be more thoughtful and critical of our participation in perpetuating Whiteness. Across the articles, I explore how my attempts to embody antiracist praxis as a White teacher educator are still fraught with performances of Whiteness.In the first article, I use interviews from student-nominated exemplary social justice faculty to describe concrete practices of antiracist teacher education praxis. The four practices that emerge include: model vulnerability, shift agency to students, build community, and pose questions. Consistent across these findings is the belief that teacher education should be a project in collective humanization; and further, that it must be grounded in critical race theories.The second article follows my attempts to employ each of the four practices listed above throughout one semester of teaching a diversity-related course. The purpose of this article is to highlight the tensions I feel trying to embody this pedagogical stance as a White female teacher educator. My findings, presented in the form of fictionalized vignettes, reveal very concrete ways that I continue to perform Whiteness as I attempt to subvert it. I therefore argue that White teacher educators must engage with more critical tools--such as autoethnography--to identify and combat the impact of our best intentions.The final article is a poetic inquiry that explores one of the aforementioned practices--model vulnerability--through a more critical lens. Vulnerability is something commonly described in normative ways, particularly in the work of Dr. Brene Brown. I explore how, as a White woman, I have more freedom to express emotions such as vulnerability without fear of repercussion or of being perceived as weak. Moreover, through using poetry as both a method of inquiry and subsequent data to analyze, I find that even the process I use to write and think about Whiteness is, in fact, reflective of my Whiteness. We as teacher educators therefore must be mindful not to describe vulnerability in normative ways that do not take into account the ever-present sociopolitical context in which we live--a context that privileges the humanity and feelings of White people while disparaging the humanity and feelings of people of Color.By using CWS across all three articles of this dissertation, I am able to highlight myriad ways that my Whiteness continues to operate insidiously even as I attempt to counter it. I offer considerations for other White teacher educators who want to move their praxis closer to being actively antiracist, ultimately hoping that more will endeavor to do this kind of work.
Show less

Title: Influence of landscape composition, landscape diversity, and conservation management on bee health via a pollen nutrition mechanism
Creator: Quinlan, Gabriela Marie
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Bees are the most important pollinators in agricultural systems, with honey bees (Apis mellifera L.) in particular providing the majority of pollination services on commercial farms. However, due to interacting stressors including lack of nutrition and disease, honey bees and other bee species are experiencing elevated loss rates compared to historical records. Access to abundant, high quality, continuous nutrition in the landscape has been suggested as a means of promoting bee health. To...
Show moreBees are the most important pollinators in agricultural systems, with honey bees (Apis mellifera L.) in particular providing the majority of pollination services on commercial farms. However, due to interacting stressors including lack of nutrition and disease, honey bees and other bee species are experiencing elevated loss rates compared to historical records. Access to abundant, high quality, continuous nutrition in the landscape has been suggested as a means of promoting bee health. To test this, I studied honey bee and bumble bee colonies in 12 apiaries that ranged in land cover composition of the surrounding forage landscape. Honey bee colony cluster size and brood area at the end of the summer were most closely related to post-spring pollination colony size and other colony-level variation, whereas bumble bee colony weight, gyne and drone production were related to surrounding land covers. This demonstrates the importance of accounting for potentially confounding honey bee colony variation in landscape-scale studies. To determine if diversity of land covers affected honey bee pollen foraging and colony size, I also measured honey bee colony size and incoming pollen at 12 apiaries located within landscapes of differing land cover diversity, and found that the relationship between land cover diversity, incoming pollen quantity and colony cluster size changed over time. This suggests that land cover diversity alone is insufficient for predicting patterns in honey bee landscape nutrition studies in this region. Conservation Reserve Program (CRP) land may include flowering, herbaceous species in seed mixes, but in states such as Michigan with abundant forage in unmanaged habitats, it is unclear if CRP investments have unique floral composition, and foraging by honey bees and wild bees. I assessed floral composition and bee visitation on CRP land as compared to analogous unmanaged fields and roadside ditches in 31 triplicate sites. Floral abundance, species richness, native flower abundance, and inflorescence coverage were all higher on CRP land, as were honey bee and wild bee visitation, indicating that herbaceous CRP promotes bee foraging through unique floral composition, namely floral density. By assessing the quantity and quality of incoming pollen at apiaries while concurrently surveying floral communities in nearby grassy-herbaceous forage habitat, I found that crude protein in collected pollen decreased throughout the summer, concurrent with decreasing floral richness and abundance. This suggests pollinator plantings should include protein-rich, late-blooming species in their seed mixes. Because nutrition is closely tied to disease in honey bees, supplementing protein may promote recovery from diseases such as European foulbrood. To compare different approaches to managing this disease, European foulbrood-infected colonies were treated with traditional antibiotics, antibiotics with a soy-based protein supplements, soy-based supplement alone, pollen-based supplement, probiotics, or left untreated. There was no significant difference among non-antibiotic treatments in post-treatment recovery speed or nurse bee physiology, suggesting these supplemental feeding treatments and probiotics provide no treatment benefits for European foulbrood. Based on this research, accounting for colony-level variation is essential in honey bee landscape studies. Adding pollinator conservation habitat with an increased emphasis on late-season, protein-rich pollen species in seed mixes can benefit honey bees and wild bee species. This work provides new insights into the effects of landscapes on honey bee and wild bee foraging, nutrition and health by examining different aspects of these indirect relationships.
Show less

Title: Finding, creating, and following footprints : the integration of indigenous knowledge in Palau Community College
Creator: Hannibal, Joy Renee
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Little research exists on the specific ways that Indigenous ways of being, knowing and doing are integrated in institutions of higher education across Micronesia. This research study illuminates through case study the position of Palauan Knowledge within Palau Community College. An Indigenous methodology set within a broader Indigenous research paradigm (Wilson, 2008) is utilized to align with Palauan values of respect (omenguul) and responsibility (ngerachel). Through interviews (chelededuch...
Show moreLittle research exists on the specific ways that Indigenous ways of being, knowing and doing are integrated in institutions of higher education across Micronesia. This research study illuminates through case study the position of Palauan Knowledge within Palau Community College. An Indigenous methodology set within a broader Indigenous research paradigm (Wilson, 2008) is utilized to align with Palauan values of respect (omenguul) and responsibility (ngerachel). Through interviews (chelededuch) with nine collaborators, in addition to fieldnotes, observations, and archival documents, this study aimed to answer the following research questions: How is Indigenous Knowledge incorporated within Palau Community College (PCC)? Secondly, how do stories from Indigenous teachers and Indigenous learning environments inform PCC? Findings from this study reveal experiences of separation from Palauan Knowledge and the actions some collaborators took to preserve Palauan Knowledge. Collaborators' narratives highlight several instances where Palauan knowledge is honored within the college through visual and oral representations as well as with academic and community programming. Continuity of Palauan Knowledge through ongoing opportunities to sustain practices in and outside of the college is explored in the final reflections of collaborators who continue to challenge perspectives that Indigenous Knowledge is in the past. Ultimately, this study lays a foundation for the argument that Palauan Knowledge is demonstrated as resilient, dynamic and adaptive to the needs of community. Recommendations concerning the elevation of Indigenous Knowledge at Palau Community College and other institutions of higher education that reside on Indigenous land are offered.
Show less

Title: There is no such thing as the voiceless : listening to the voices of elementary youth to affect school change
Creator: Mauldin, Courtney Camille
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Using an arts-based methodology, this dissertation project moves beyond the traditional bounds of student and leader in schools by examining how elementary-aged youth of color are positioned to affect change within their school by way of centering student voice. Further, this study examines how school leaders engage the voices of elementary-aged youth of color. While there has been emerging research on the inclusion of student voice in the field of educational leadership, there is limited...
Show moreUsing an arts-based methodology, this dissertation project moves beyond the traditional bounds of student and leader in schools by examining how elementary-aged youth of color are positioned to affect change within their school by way of centering student voice. Further, this study examines how school leaders engage the voices of elementary-aged youth of color. While there has been emerging research on the inclusion of student voice in the field of educational leadership, there is limited literature that provides an in-depth description of how school leaders implement student voice in the elementary school setting. Drawing from a critical leadership framework and Black feminist practices and epistemologies, the aims of this study are to contribute to the literature on student voice in the educational leadership field and to examine the ways in which youth voice can influence more critically reflexive approaches to school leadership practice. Using an art-based approach in our weekly dialogue group allowed for students to create poetry, collage, and other constructed artifacts that conveyed their ideas about what leadership should encompass and the changes they desired to see in their school, society, and local community. Through a thematic analysis of field notes, artifacts composed by the youth, recorded dialogue sessions with youth and repetitive interview sessions with the school leader, this study documents both youth and school leader perceptions of student voice and leadership in the elementary school context.
Show less

Title: Determination of the role of ventral tegmental area SGK1 catalytic activity and phosphorylation in drug behavior
Creator: Doyle, Marie Althea
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Substance use disorder is a chronic, relapsing disease that affects 20.3 million people in the United States. Despite its prevalence, treatments remain inadequate in part due to our limited understanding of the neuroadaptations induced by drug use. Drugs of abuse are known to regulate the activity of the mesolimbic dopamine (DA) system, a key circuit for drug action and reward. Specifically, drug-induced changes in ventral tegmental area (VTA) cellular activity and gene regulation have been...
Show moreSubstance use disorder is a chronic, relapsing disease that affects 20.3 million people in the United States. Despite its prevalence, treatments remain inadequate in part due to our limited understanding of the neuroadaptations induced by drug use. Drugs of abuse are known to regulate the activity of the mesolimbic dopamine (DA) system, a key circuit for drug action and reward. Specifically, drug-induced changes in ventral tegmental area (VTA) cellular activity and gene regulation have been linked to behavioral outputs associated with addiction. Previous work determined that serum- and glucocorticoid-inducible kinase 1 (SGK1) mRNA expression, catalytic activity, and phosphorylation were increased by chronic administration of cocaine or morphine; however, it was unknown if these changes contributed to drug reward behaviors. In this thesis, I utilized transgenic and viral-mediated SGK1 manipulations to determine the impact of altered SGK1 expression and function on cocaine and morphine related-behaviors, primarily assessed by cocaine conditioned place preference (CPP) and voluntary morphine intake using a two-bottle choice task. I first established that that while SGK1 is transcriptionally upregulated and biochemically modified by chronic-drug administration, SGK1 deletion in either the VTA or in DA neurons was not capable of altering drug reward behaviors. Though SGK1 gene deletion did not alter reward, I next showed that viral-mediated overexpression of SGK1 mutants in the VTA of adult mice produced behaviorally relevant effects on cocaine and morphine reward. Specifically, intra-VTA infusion of a catalytically inactive SGK1 mutant (K127Q) significantly decreased cocaine CPP and morphine preference, suggesting that decreased VTA SGK1 activity is sufficient to impair drug reward. To more fully understand the role of VTA SGK1 in behaviors relevant to addiction, I manipulated SGK1 expression in a cell type-specific manner to determine whether SGK1 activity in VTA DA or GABA neurons drove the observed behavioral effects. Utilizing novel Cre-dependent viral constructs, I found that reduced SGK1 activity in VTA DA neurons significantly decreases cocaine CPP, while this same manipulation in VTA GABA neurons had no effect. Interestingly, this manipulation did not alter morphine preference. Future studies seek to determine a potential mechanism for these behavioral effects using ex vivo slice electrophysiology, and parallel studies currently explore the potential effects of a similarly regulated SGK1 phosphorylation site (Ser78) in drug-related behaviors. Altogether, these studies will allow for the identification of the specific cells and circuits that are critical for SGK1-mediated effects on drug reward and intake, a necessary step in assessing the feasibility of SGK1 inhibition as a novel therapeutic avenue for addiction.
Show less

Title: Observers as a tool to reduce information exchange and increase convergence rate in multi-agent systems
Creator: Chowdhury, Dhrubajit
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Observers form an integral part of output feedback control of linear and nonlinear systems. This dissertation investigates the use of observers in multi-agent systems to reduce information exchange and increase the convergence rate. Multi-agent systems have been immensely popular since the last two decades due to their broad applicability in practical problems, some of them being distributed sensor networks, formation control, and cooperative robotics. The controller for each agent is...
Show moreObservers form an integral part of output feedback control of linear and nonlinear systems. This dissertation investigates the use of observers in multi-agent systems to reduce information exchange and increase the convergence rate. Multi-agent systems have been immensely popular since the last two decades due to their broad applicability in practical problems, some of them being distributed sensor networks, formation control, and cooperative robotics. The controller for each agent is distributed in nature, which means that it only depends on the local information available to it. The distributed approach has several advantages such as less computational effort, reliability, etc., compared to the centralized one where there is a central agent that does all the computations and then makes the decision.The convergence rate of consensus algorithms is an important performance measure. We show that by using observers, we can increase the convergence rate of the consensus algorithm. The observer is used for estimating the missing links at each agent. We also study the effect of increasing network size on the consensus algorithm. For networks without a leader, the rate of convergence of the consensus protocol becomes slow for certain classes of graphs, while for networks with a single leader, the convergence rate becomes slow for undirected graphs. We design scalable consensus algorithms for first-order linear agents and second-order nonlinear heterogeneous agents where the convergence rate remains almost invariant of the network size.We consider the case of reduced information exchange in a network of nonlinear heterogeneous agents having the same relative degree r. We use observers along with feedback control to compensate for the heterogeneity at each agent. Finally, motivated by the practical application of multi-agent systems to power systems frequency synchronization, we fuse dynamic consensus algorithms with observers to achieve practical frequency synchronization under time-varying power-demand. We show that the frequency synchronization error can be made arbitrarily small by tuning controller and observer parameters.
Show less

Title: The effects of genetic background on the evolution of antibiotic resistance and its fitness costs
Creator: Card, Kyle Joseph
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Antibiotic resistance is a growing public-health concern. Efforts to control the emergence and spread of resistance would benefit from an improved ability to forecast when and how it will evolve. To predict the evolution of resistance with accuracy, we must understand and integrate information about many factors, including a bacterium's evolutionary history. This dissertation centers on the effects of genetic background on the evolution of phenotypic resistance, its genetic basis, and its...
Show moreAntibiotic resistance is a growing public-health concern. Efforts to control the emergence and spread of resistance would benefit from an improved ability to forecast when and how it will evolve. To predict the evolution of resistance with accuracy, we must understand and integrate information about many factors, including a bacterium's evolutionary history. This dissertation centers on the effects of genetic background on the evolution of phenotypic resistance, its genetic basis, and its fitness costs. To address these issues, I used Escherichia coli strains from the long-term evolution experiment (LTEE) that independently evolved for multiple decades in an environment without antibiotics.First, I examined how readily these LTEE strains could overcome prior losses of intrinsic resistance through subsequent evolution when challenged with antibiotics. Second, I investigated whether lineages founded from different genotypes take parallel or divergent mutational paths to achieve increased resistance. Third, I tested whether fitness costs of resistance mutations are constant across different genetic backgrounds. In these studies, I focused attention on the interplay between repeatability and contingency in the evolutionary process. My findings demonstrate that genetic background can influence both the phenotypic and genotypic evolution of resistance and its associated fitness costs. I conclude this dissertation with a broader discussion about these and other factors that can influence the evolution of antibiotic resistance, and their clinical and public-health implications.
Show less

Title: The politics of the fall in St. Augustine of Hippo
Creator: Giles, Michael T.
Date: 2020
Collection: Electronic Theses & Dissertations
Description: This dissertation examines the thought of St. Augustine of Hippo, arguing for the importance of "the fall" of mankind for contemporary political life. Augustine believes that human nature was shaped by a cataclysmic fall from grace. His influential interpretation of the Biblical story is well-known, and yet the political features of this account have not been subjected to a systematic study. This work aims to remedy this shortcoming by wrestling with Augustine's presentation of the fall...
Show moreThis dissertation examines the thought of St. Augustine of Hippo, arguing for the importance of "the fall" of mankind for contemporary political life. Augustine believes that human nature was shaped by a cataclysmic fall from grace. His influential interpretation of the Biblical story is well-known, and yet the political features of this account have not been subjected to a systematic study. This work aims to remedy this shortcoming by wrestling with Augustine's presentation of the fall across a wide variety of political concerns. The dissertation proceeds in four substantive chapters, each of which deals with a different sphere of human endeavor or hope. Chapter one considers Augustine's account of work before and after the fall, and compares his view with the more contemporary and secular ideas of Karl Marx. The second chapter analyzes the effect of the fall on human sociality. It makes the case that Augustine sees a duality in mankind's originally social nature. In the third chapter, I contend that Augustine sees the basic political problems of desire and mortality as dominating the life of mankind as a fallen creature. It is the fall that transforms these things into problems for us. Finally, the fourth chapter gives an original account of Augustine's treatment of glory-seeking. From all these chapters a surprising conclusion can be drawn: the idea of human corruption, far from simply denouncing humanity as depraved, articulates a much more nuanced, balanced, and ultimately realistic account of political life.
Show less

Title: Validation and application of experimental framework for the study of vocal fatigue
Creator: Berardi, Mark Leslie
Date: 2020
Collection: Electronic Theses & Dissertations
Description: In recent years, vocal fatigue research has been increasingly studied particularly with application to the reduction of its impact on schoolteachers and other occupational voice users. However, the concept of vocal fatigue is complex and neither well defined or well understood. Vocal fatigue seems to be highly individualized and dependent on several underlying factors or concepts. The purpose of this dissertation is to propose and support through experimentation a framework that can identify...
Show moreIn recent years, vocal fatigue research has been increasingly studied particularly with application to the reduction of its impact on schoolteachers and other occupational voice users. However, the concept of vocal fatigue is complex and neither well defined or well understood. Vocal fatigue seems to be highly individualized and dependent on several underlying factors or concepts. The purpose of this dissertation is to propose and support through experimentation a framework that can identify the factors contributing to vocal fatigue. The main hypothesis is that the change in vocal effort, vocal performance, and/or their interaction through a vocal demand (load) will implicate vocal fatigue. To test this hypothesis, three primary research questions and experiments were developed. For all three experiments vocal effort was rated using the Borg CR-100 scale and vocal performance was evaluated with five speech acoustic parameters (fundamental frequency mean and standard deviation, speech level mean and standard deviation, and smoothed cepstral peak prominence).The first research question tests whether perceived vocal effort can be measured reliably and if so, how vocal performance in terms of vocal intensity changes with a vocal effort goal. Participants performed various speech tasks at cued effort levels from the Borg CR-100 scale. Speech acoustic parameters were calculated and compared across the specific vocal effort levels. Additionally, the test-retest reliability across the effort levels for speech level was measured. Building from that experiment, the second research question was to what degree are vocal performance and vocal effort related given talker exposure to three equivalent vocal load levels. This experiment had participants performing speech tasks when presented with three different equivalent vocal load scenarios (communication distance, loudness goal, and background noise); for a given load scenario, participants rated their vocal effort associated with these tasks. Vocal effort ratings and measures of vocal performance were compared across the vocal load levels. The last research question built on the previous two and asked to what degree do vocal performance, vocal effort, and/or their interaction change given a vocal load of excess background noise (noise load) over a prolonged speaking task (temporal load). To test this, participants described routes on maps for thirty minutes in the presence of loud (75 dBA) background noise. Vocal effort ratings and measures of vocal performance were compared throughout the vocal loading task.The results indicate that elicited vocal effort levels from the BORG CR-100 scale are distinct in vocal performance and reliable across the participants. Additionally, a relationship between changes in vocal effort and vocal performance across the various vocal load levels was quantified. Finally, these findings support the individual nature of the complex relationship between vocal fatigue, vocal effort, and vocal performance due to vocal loads (via cluster and subgroup analysis); the theoretical framework captures this complexity and provides insights into these relationships. Future vocal fatigue research should benefit from using the framework as an underlying model of these relationships.
Show less

Title: A topological study of toroidal dynamics
Creator: Gakhar, Hitesh
Date: 2020
Collection: Electronic Theses & Dissertations
Description: This dissertation focuses on developing theoretical tools in the field of Topological Data Analysis and more specifically, in the study of toroidal dynamical systems. We make contributions to the development of persistent homology by proving Kunneth-type theorems, to topological time series analysis by further developing the theory of sliding window embeddings, and to multiscale data coordinatization in topological spaces by proving stability theorems. First, in classical algebraic topology,...
Show moreThis dissertation focuses on developing theoretical tools in the field of Topological Data Analysis and more specifically, in the study of toroidal dynamical systems. We make contributions to the development of persistent homology by proving Kunneth-type theorems, to topological time series analysis by further developing the theory of sliding window embeddings, and to multiscale data coordinatization in topological spaces by proving stability theorems. First, in classical algebraic topology, the Kunneth theorem relates the homology of two topological spaces with that of their product. We prove Kunneth theorems for the persistent homology of the categorical and tensor product of filtered spaces. That is, we describe the persistent homology of these product filtrations in terms of that of the filtered components. Using these theorems, we also develop novel methods for algorithmic and abstract computations of persistent homology. One of the direct applications of these results is the abstract computation of Rips persistent homology of the N-dimensional torus.Next, we develop the general theory of sliding window embeddings of quasiperiodic functions and their persistent homology. We show that the sliding window embeddings of quasiperiodic functions, under appropriate choices of the embedding dimension and time delay, are dense in higher dimensional tori. We also explicitly provide methods to choose these parameters. Furthermore, we prove lower bounds on Rips persistent homology of these embeddings. Using one of the persistent Kunneth formulae, we provide an alternate algorithm to compute the Rips persistent homology of the sliding window embedding, which outperforms the traditional methods of landmark sampling in both accuracy and time. We also apply our theory to music, where using sliding windows and persistent homology, we characterize dissonant sounds as quasiperiodic in nature.Finally, we prove stability results for sparse multiscale circular coordinates. These coordinates on a data set were first created to aid non-linear dimensionality reduction analysis. The algorithm identifies a significant integer persistent cohomology class in the Rips filtration on a landmark set and solves a linear least squares optimization problem to construct a circled valued function on the data set. However, these coordinates depend on the choice of the landmarks. We show that these coordinates are stable under Wasserstein noise on the landmark set.
Show less

Title: Embodying ubuntu, invoking sankofa, and disrupting with fela : a co-exploration of social issues and critical mathematics education with Sub-Saharan African youth
Creator: Osibodu, Oyemolade Omoyosola
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The purpose of this qualitative research is to study if and how Sub-Saharan African youth use mathematics in understanding social issues related to the African continent. I co-explored with five Sub-Saharan African youth over the course of a semester and leaned on what Koro-Ljungberg (2012) termed methodological fluidity. I draw on decolonial theory from an African perspective (Ndlovu-Gatsheni, 2015, 2018) and African [decolonial] frameworks (Ubuntu, Sankofa, Fela Anikulapo-Kuti Music [FAM])...
Show moreThe purpose of this qualitative research is to study if and how Sub-Saharan African youth use mathematics in understanding social issues related to the African continent. I co-explored with five Sub-Saharan African youth over the course of a semester and leaned on what Koro-Ljungberg (2012) termed methodological fluidity. I draw on decolonial theory from an African perspective (Ndlovu-Gatsheni, 2015, 2018) and African [decolonial] frameworks (Ubuntu, Sankofa, Fela Anikulapo-Kuti Music [FAM]) to center the perspectives of the colonized Other, decenter power within the research space, seek clarity on what we sought to disrupt, and find joy in the research space. Unlike previous research in this field, this study does not focus on learning new mathematics, rather, I sought to investigate what knowledges youth draw on in their exploration of these social issues.The findings of this study highlight the focus of Sub-Saharan's youth need to re-read and re-write their African world with and without mathematics. Youth were invested in re-writing false narratives about the African continent by calling forth African Indigenous ways of knowing. This rewriting led to epistemic freedom and cognitive justice - an essential component of social justice - that redresses the loss of Indigenous knowledges. Despite this, there was still tension in both recognizing and accepting African Indigenous ways of knowing along with the belief that school mathematics is neutral.In the final chapter, I discuss the implications of this research such as the bridging together of critical mathematics education, ethnomathematics, and Indigenous ways of knowing. I also discuss how decolonial theory and African decolonizing methodologies opened space in this research for insights that might not have been evidenced using other theories and methodologies.
Show less

Title: Why do people comply and cooperate with the police? : a cultural explanation
Creator: Lee, Sung Uook
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The current dissertation examines police legitimacy in the South Korean context. Prior research has tended to focus on the relational aspects of police-citizen relationships and is generally suggestive of an important role for a variety of relational constructs. Although important, this work has tended to pay less attention to person-level constructs within individuals. Furthermore, prior police legitimacy research lacks examination of cultural values as well and only focuses on police...
Show moreThe current dissertation examines police legitimacy in the South Korean context. Prior research has tended to focus on the relational aspects of police-citizen relationships and is generally suggestive of an important role for a variety of relational constructs. Although important, this work has tended to pay less attention to person-level constructs within individuals. Furthermore, prior police legitimacy research lacks examination of cultural values as well and only focuses on police-citizen encounters. Additionally, although recent studies regarding South Korean public perception of police legitimacy have been emerging, more extensive investigation is needed. The primary goal of the current study is to examine the impact of propensity to trust and Confucian values on perceived police legitimacy, operationalized here using the Integrated Framework of Legitimacy (Hamm et al, 2017). To this end, the current dissertation uses data collected from South Korean university students to contribute to the literature (1) an evaluation of the role of person-level constructs in predicting public perceptions of police legitimacy and (2) a first test of the IFL in the South Korean context.
Show less

Title: "Because we are important!" : music educators and special education paraprofessionals in a community of practice
Creator: Grimsby, Rachel Leigh-Mallory
Date: 2020
Collection: Electronic Theses & Dissertations
Description: With the intent of developing an effective community of practice (CoP) that addresses the professional development, instructional, and collaborative needs of music educators and special education paraprofessionals (SEPs), the purpose of this study was to examine the instructional processes, perceptions, and practices of music educators and SEPs in regard to teaching music to students with disabilities. The "grand tour" question of this study was: How does a community of practice offer...
Show moreWith the intent of developing an effective community of practice (CoP) that addresses the professional development, instructional, and collaborative needs of music educators and special education paraprofessionals (SEPs), the purpose of this study was to examine the instructional processes, perceptions, and practices of music educators and SEPs in regard to teaching music to students with disabilities. The "grand tour" question of this study was: How does a community of practice offer collaboration and instructional support for music educators and SEPs? Research questions were as follows: 1) How do music educators and SEPs interact within a community of practice? 2) Does a community of practice impact the instructional and collaborative practices of music teachers and SEPs, and if so, how does it manifest in the classroom? 3) How does a community of practice shift participants' pedagogical and philosophical beliefs concerning teaching students with disabilities? 4) How does a community of practice facilitate growth and collaborative planning in ways that the school structures cannot? What does this tell us about music educator and SEP needs? 5) What aspects of the community of practice were most difficult for the participants, the easiest, and what did they find most useful?This was an instrumental case study (Stake, 1995, 2005; Merriam, 1988, 1998) of a group of music educators and special education paraprofessionals in a social learning community. As participants met, and relationships began to form, a community of practice emerged. Six participants, three music educators and three SEPs participated in this study which consisted of eight collaborative meetings that took place over the course of four months. I collected throughout the study, beginning with initial interviews and ending with exit interviews. Participants engaged in five meetings in-person at a local library, and three online via Discord®, an online voice and text chat platform. I observed in their classrooms twice over the duration of the study. Participants found the collaborative nature of the group to be the most beneficial. While instructional practices were only impacted moderately through participation in this community of practice, participant perceptions of their colleagues were changed. Participants stated they felt they understood more fully the perspective of their colleagues as well as how to more effectively collaborate with them.
Show less

Title: Discovering the progenitors to typical field millisecond pulsar binaries
Creator: Swihart, Samuel John
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Neutron stars in low-mass binaries can accrete matter and angular momentum from a non-degenerate companion star and be spun-up to rapid spin periods, making them detectable as millisecond radio pulsars (MSPs). Although the swollen stellar companion transfers mass onto the neutron star for hundreds of millions of years or more, most MSPs in the Galactic field have a compact white dwarf companion in a wide orbit, representing the end product of the spin-up process. Following the launch of the ...
Show moreNeutron stars in low-mass binaries can accrete matter and angular momentum from a non-degenerate companion star and be spun-up to rapid spin periods, making them detectable as millisecond radio pulsars (MSPs). Although the swollen stellar companion transfers mass onto the neutron star for hundreds of millions of years or more, most MSPs in the Galactic field have a compact white dwarf companion in a wide orbit, representing the end product of the spin-up process. Following the launch of the \emph{Fermi} Space Telescope, it became clear MSPs were nearly ubiquitous emitters of high-energy $\gamma$-rays. Using multiwavelength follow-up observations of unidentified \emph{Fermi} sources, the rarely observed binary MSPs with non-degenerate companions started being discovered in greater numbers. In this dissertation, I expand this population of rare MSPs with new discoveries and present a novel method for identifying and characterizing new Galactic compact neutron star binaries: cross-matching unassociated Fermi sources with short-period optical variables from high-cadence all-sky surveys. This technique has allowed for the discovery of a number of new systems with non-degenerate companions in orbits around previously unknown MSPs. Among these are a few systems with red giant companions in relatively wide orbits ($P\gtrsim1$ d) that will naturally evolve into the MSP--white dwarfs that represent the bulk of known MSP binaries. The long orbital periods, giant companions, and inferred evolutionary tracks of these systems indicate they are entirely different from the close-orbit MSP binaries being found recently with \emph{Fermi}, and suggests a new subclass of compact neutron star systems that are the progenitors of typical field MSP binaries.
Show less

Title: Essays on the economics of organ transplantation and hemodialysis
Creator: Choi, Yeon
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Chapter 1. The Effect of Broader Liver Sharing on Patient Outcomes and Offer Acceptance: This paper evaluates a liver allocation policy known as Share 35, which provides transplant candidates facing high mortality risks with priority for livers obtained from relatively distant geographic areas. Exploiting the variation in the access to liver transplants across transplant candidates, I show that increasing access to liver transplants is an effective way to reduce mortality rates. Although the...
Show moreChapter 1. The Effect of Broader Liver Sharing on Patient Outcomes and Offer Acceptance: This paper evaluates a liver allocation policy known as Share 35, which provides transplant candidates facing high mortality risks with priority for livers obtained from relatively distant geographic areas. Exploiting the variation in the access to liver transplants across transplant candidates, I show that increasing access to liver transplants is an effective way to reduce mortality rates. Although the policy is well-targeted, I find that the policy causes unintended effects on the quality of transplanted livers and transplant candidates' liver offer-acceptance incentives. Because the policy promotes liver sharing across areas, targeted candidates receive a lower quality of livers due to longer liver transportation times. However, those candidates receive a compensation on liver quality by receiving livers with better donor characteristics. To further understand the mechanism of the compensation, I develop a strategic liver search model and estimate the model with match-run data that contain offer-acceptance decision histories for all donated livers. I find that the policy enables targeted candidates to be more selective of liver and transfer some of their quality loss to others.Chapter 2. The Role of Kidney Allocation Policy in Addressing Kidney Shortages: I examine whether prioritizing certain types of transplant candidates in deceased-donor kidney allocation can increase the total number of kidney transplants. Transplant candidates strategically choose one of the two kidney sources, namely, deceased-donor and living-donor kidneys. While deceased-donor kidneys are available for all transplant candidates (similar to public goods), living-donor kidneys are only available for the designated recipients by the donors (similar to private goods). Using a regression discontinuity design, I show that transplant candidates are less likely to choose living-donor kidneys when they have better access to deceased-donor kidneys, which can be interpreted as a crowd-out effect. Furthermore, I find that the size of the effect varies substantially across race, blood type, and dialysis status of transplant candidates. The result implies that prioritizing transplant candidates, who are less prone to crowd-out, in deceased-donor kidney allocation could make policies designed to increase the number of deceased donors more effective.Chapter 3. The Strategic Location Choice of For-profit Hemodialysis Facilities in the U.S.: In the last chapter, I identify key factors related to the location choice of for-profit hemodialysis facilities using a dataset from the United States Renal Data System (USRDS) and structural methods. All patients with kidney failure need to receive hemodialysis treatment regularly and permanently. Because dialysis treatments are homogeneous across facilities, patients are likely to choose a treatment facility based on the distance from their homes. The strategic model introduced by Seim (2006) involves a static and incomplete information game among dialysis facilities for entry and positioning in a market. The estimation results show that in choosing an optimal location, a tradeoff occurs between local demand and competition with potential entrants.
Show less

Title: Understanding management and landscape influences on the harvest of male white-tailed deer across a large geographic region
Creator: Cain, Rebecca Lynne
Date: 2020
Collection: Electronic Theses & Dissertations
Description: The North American Model of Wildlife Conservation relies on the active participation of citizen hunters to achieve management goals. One factor that motivates hunters to become active participants is an opportunity to harvest a mature white-tailed deer (Odocoileus virginianus) with large antlers, especially the case for achievement-oriented wildlife recreationists. Variation in antler conformation and size among white-tailed deer is noticeable across landscapes. Moreover, when mapped, there...
Show moreThe North American Model of Wildlife Conservation relies on the active participation of citizen hunters to achieve management goals. One factor that motivates hunters to become active participants is an opportunity to harvest a mature white-tailed deer (Odocoileus virginianus) with large antlers, especially the case for achievement-oriented wildlife recreationists. Variation in antler conformation and size among white-tailed deer is noticeable across landscapes. Moreover, when mapped, there is obvious spatial heterogeneity in the harvests of record deer (e.g., deer with large antlers that qualify for entry in the Boone and Crockett records) across the United States, with the majority of entries coming from the Midwestern region. This dissertation should engage the interests of wildlife biologists and researchers. Chapter 1 focuses on testing hypotheses about harvest outcomes for antler point restrictions in the state of Michigan. Chapter 2 evaluates spatially explicit trends in antler sizes of record deer across the Midwestern United States. Chapter 3 evaluates the degree to which management regulations influenced the harvest of record deer in the Midwest United States. Chapter 4 focuses on potential issues related to reporting bias and proposes an adaptation of N-mixture models to account for imperfect detection. Findings from this research include: 1) the importance of spatial context when evaluating trends in harvest data across a large geographic region; 2) antler point restrictions do indeed protect yearling males from harvest and advance the age structure of male harvest; 3) implementing antler point restrictions did not increase antlerless harvest or change the trajectory in hunter numbers; 4) antler sizes of record deer in the Midwest showed increasing trends; 5) harvests of record deer were greater in areas with management regulations that restricted the buck harvest; 6) more record deer were reported when at least 1 record deer was reported the previous year; 7) detection of harvests of record deer do not follow any spatial or temporal pattern.As interest in quality deer management and harvesting adult males with large antlers increases, it is important for wildlife managers and hunters to understand how regulations can influence harvests of record deer. My work offers insights into the relationships between management strategies and harvest outcomes. This research provides managers important information about factors affecting harvests of record deer, outcomes of management regulations, and inherent differences in record deer harvests and characteristics among ecoregions. Managers can draw on the insights gained from this dissertation research during the decision-making process when setting annual hunting regulations, as well as communicating reasonable expectations for deer populations to hunters and other interested stakeholder groups.
Show less

MSU Libraries

Digital Repository

Pages

Pages

MSU Libraries

Digital Repository

You are here

Search results

Pages

Pages