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PARAMETER ESTIMATION FOR GAUSSIAN RANDOM FIELDS AND MULTIVARIATE GAUSSIAN RANDOM PROCESSES UNDER FIXED-DOMAIN ASYMPTOTICS
Get PDFThesis (Ph.D.)--Michigan State University. Statistics - Doctor of Philosophy, 2024This dissertation explores parameter estimation for Gaussian random fields and multivariate Gaussian random processes under fixed-domain asymptotics, a crucial framework for modeling spatial and temporal data. Unlike increasing-domain asymptotics, fixed-domain asymptotics involve a growing number of observations within a fixed, bounded region, leading to denser data. This scenario is common in applications such as image processing, where the spatial domain is constrained by the finite size of the sensor array. First, we study the parameter estimation for a Gaussian field with a multiplicative covariance function, which is particularly relevant in computer experiments. We propose an increment-based estimator for estimating variance and scale parameters, and subsequent analysis shows that the estimator is both strongly consistent and asymptotically normal. Next, we extend the analysis to the bivariate Ornstein-Uhlenbeck process, constructing an explicit estimator that is strongly consistent and asymptotically normal. This estimator, requiring no prior parameter information, is shown to have the same asymptotic covariance matrix as that of the maximum likelihood estimator (MLE).Finally, we investigate asymptotic properties of MLE for the isotropic powered exponential field. Unlike the Mat\'ern model, the spectral density of the powered exponential model poses analytical challenges. We also establish conditions for the equivalence of Gaussian measures, providing a contrast to the orthogonality conditions found in earlier studies.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Evolutionary and applied approaches for the management of invasive swallow-wort vines (Vincetoxicum spp.) : biological control, ecosystem restoration and consequences for monarch butterflies (Danaus plexippus)
Get PDFThesis (Ph.D.)--Michigan State University. Entomology - Doctor of Philosophy, 2024Classical weed biological control uses natural enemies that have co-evolved with their host plants in their native range and provides a sustainable and effective strategy for the long-term management of invasive species. However, its successful implementation encounters several challenges that must be addressed to maximize efficacy. Biological control agents, often reared extensively in quarantine, face issues like adaptation to culture, reduced genetic diversity and inbreeding, which can affect their establishment and efficacy. Upon implementation of biological control, site restoration may be limited without the proper integration of supplemental restoration techniques. Restoration techniques combined with biological control are not extensively studied, limiting their widespread adoption and application. Furthermore, the impact of invasive species to native species of concern is important to optimize management plans. This dissertation investigates the integration of applied and evolutionary approaches in the control of invasive swallow-wort vines (Vincetoxicum spp.), emphasizing the importance of genetic background when employing the biocontrol agent Hypena opulenta, the restoration of invaded forests, and the implications for the monarch butterfly (Danaus plexippus). In Chapter 1, I research the importance of genetic background by creating an outbred population by crossing a long-term laboratory-reared population with individuals from an-established population of H. opulenta in the field. These populations are used to understand the role of intraspecific outcrossing in enhancing the fitness and neutral genetic diversity of Hypena opulenta with laboratory and field experiments alongside molecular analysis. The results show that increases in neutral genetic variation can translate to tangible fitness benefits in the outbred population measured as increases in production of pupae in the laboratory, and larval feeding rates and second-generation adult production under field conditions. In Chapter 2, I research how biological control, manual removal of swallow-wort, and native seeding, alone and combined, can impact restoration success. The results show that when native seeding is combined with biological control, swallow-wort cover is reduced, and species richness is enhanced. In Chapter 3, I investigate the effects of genetic background and demography in the establishment success of Hypena opulenta by conducting experimental field releases. However, I was not able to understand this relationship because of establishment failure. In repeat releases two years later, where genetic background was the sole focus, the results mirrored patterns seen in the field cage experiments from Chapter 1 with the outbred population eating more plant tissue and producing more adults compared to lower genetic diversity laboratory reared and field collected populations. Finally, in Chapter 4, I explore the oviposition choices of the monarch butterfly in Michigan. I determine the frequency with which monarch butterflies mistakenly lay eggs on swallow-worts under natural field conditions and use laboratory experiments to uncover the underlying mechanisms of their oviposition decisions, aiming to clarify the factors influencing monarch egg-laying behavior. Field results showed that monarchs can lay up to 17% of their eggs on swallow-wort locally, and about 8% overall. Despite oviposition failure in the lab experiment, monarch larvae exhibited 16% mortality in the lab directly attributed to feeding on swallow-wort. This dissertation contributes to the discourse on ecological restoration, biological control, and provides insights for future conservation and management endeavors in ecosystems threatened by invasive species.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
IMPACT OF MICROWAVE-BASED DRYING ON SALMONELLA INACTIVATION KINETICS, ANTIOXIDANT PROPERTIES AND QUALITY OF RED PEPPER (CAPSICUM ANNUUM)
No full textThesis (M.S.)--Michigan State University. Food Science - Master of Science, 2024The increasing number of outbreaks and recalls related to pathogen contamination of low-moisture foods, including spices, have raised concerns about their safety. The WHO has determined that red pepper poses the highest risk of Salmonella contamination. However, there is limited data on Salmonella thermal inactivation kinetics of red chili peppers. Microwave (MW) drying is an energy-efficient technique that can have a significant impact on various quality aspects of red pepper quality. This thesis investigated that the survival of S. Montevideo in red chili peppers decreased with increasing aw and treatment temperature over time (P < 0.05) and the moisture conditions played a key role in accurately describing Salmonella lethality using the log-linear Biglow model. In addition, modeling using non-isothermal temperature conditions has been shown to better describe the lethality of S. Montevideo than its counterpart. For MW drying, higher MW power (240W) resulted in lower Salmonella survival over time (P < 0.05). MW drying achieved similar quality retention to traditional drying technologies, including total phenolic, ABTS value and total capsaicinoids. Overall, the MW drying at 240W was observed to better retain the color properties and acceptable total phenolics and antioxidant capacity. This study is a first step in predicting Salmonella reduction in spices during commercial processing where temperature and air temperature change over time. This study is a first step for the development of an MW drying system to reduce Salmonella contamination levels in dried red chili peppers to reduce the use of traditional decontamination processes and improve the quality retention.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
THE REPRESENTATION OF WOMEN IN POLICING AND COMMUNITY POLICING IMPLEMENTATION
Get PDFThesis (M.S.)--Michigan State University. Criminal Justice - Master of Science, 2024Police departments are currently interested in increasing the presence of female personnel. Providing a diversified spectrum of communication and problem-approaching perspectives through female voices could bring additional insights to community policing. The purpose of this thesis is to examine whether the representation of women in large, local departments affects community policing implementation. It utilizes the 2016 and 2020 Law Enforcement Management and Administrative Statistics (LEMAS) datasets to assess this relationship via a logistic regression. The results failed to find statistical significance between women representation across ranks and community policing implementation. Yet, one of the control variables, task scope, showed statistical significance with community policing implementation. Further research studies are encouraged to support the potential association between women representation and various forms of community policing implementation.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Seasonal Dynamics of Decomposition Ecology
Get PDFThesis (M.S.)--Michigan State University. Entomology - Master of Science, 2024All organic life, by virtue of having ever been alive, is fated to end. Life and death represent opposing binary states: an organism is either alive and its biological processes functioning, or dead, with those processes halting entirely. Of the phenomena that only carbon-based life can lay claim to, the decomposition that accompanies death stands out as the most ubiquitous. The connotation of decomposition often betrays its nature as a complex, multivariate process that is mediated by far more than just the carcass enabling it. Among the decomposers responsible for nutrient cycling in carrion systems, bacteria and blow flies (Diptera: Calliphoridae) stand out as the most effectual. The objective of this study was to examine how the microbiota of carcasses, blow fly larvae, and larval masses developed as decomposition advanced. The intent to monitor bacterial community succession with repeated measures was motivated by growing interest among researchers to properly identify and characterize core contributors of the ecological networks supported by carrion, otherwise known as the \u201cnecrobiome.\u201d To account for abiotic factors that we suspected play a role in moderating these ecosystems, we evaluated the role seasonal weather dynamics play in influencing microbiome assemblage. We predicted that postmortem microbiome composition, diversity, and succession would be drastically dissimilar between seasons by seasonal weather conditions. It was additionally hypothesized that colonization of carcasses by blow flies would significantly impact carcass bacterial community composition. Parallel predictions were made that season would, similarly, influence larval microbiome assemblage as well as the microbiota of larval masses formed by those larvae. Ultimately, we found both season and larval presence jointly influenced postmortem microbiome succession, and that postmortem microbiome diversity was significantly greater in the summer than the fall or spring, but that no significant difference existed between the fall and spring seasons themselves. Bacterial community composition differed significantly by season regardless of pairwise comparison. Blow fly colonization significantly influenced bacterial community composition in facilitating the introduction and subsequent dominance of insect-associated bacterial taxa like Ignatzschineria. Season made the most significant contributions to microbiome dissimilarity driven by humidity. These decomposition studies demonstrated the interconnectedness of life encompassed by the necrobiome and, in doing so, strengthened pretense to better evaluate inter-kingdom interactions observed in decomposition settings.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
U.S. INFANT FORMULA INDUSTRY : A QUALITATIVE ANALYSIS OF A MAJOR FOOD SAFETY RECALL AND ITS IMPLICATIONS
Get PDFThesis (M.S.)--Michigan State University. Agricultural, Food and Resource Economics - Master of Science, 2024A major food safety recall of infant formula in February 2022 caused significant disruptions in the supply chain that was already fragile, causing a severe shortage in the marketplace. The highly concentrated market structure, strict policies and regulations that characterize infant formula production further contributed to the shortage. Infant formula is a unique product with no close market substitutes available, especially for specialty formulas which are designed for babies with medical conditions. Therefore, shortages in the marketplace may threaten the lives and well-being of infants who do not have alternative sources of nutrition, particularly in the first few months of life. Given the substantial reliance on infant formula, maintaining a sufficient supply of this product in the marketplace is crucial. This makes the major recall an important case study and a policy-relevant issue. This study presents a unique contribution to the literature by investigating the infant formula industry, including the 2022 infant formula food safety recall, utilizing data and information obtained from qualitative interviews with experts in the industry. A key finding is a comprehensive map of the infant formula supply chain, shedding light on its dynamics and vulnerabilities. Additionally, the research details communication dynamics and coping strategies employed by the industry and consumers during the recall, revealing the lack of information and standards in this industry. Our study contributes to the limited literature on the infant formula industry, with the goal of developing effective strategies to enhance its resilience and affecting government policy and industry practices.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
MADE IN INDIA : CONTESTATION AND POWER DYNAMICS IN EXPORT-ORIENTED GARMENT PRODUCTION IN THE INDIAN CONTEXT
Get PDFThesis (Ph.D.)--Michigan State University. Human Resources and Labor Relations-Doctor of Philosophy, 2024Working conditions in the global garment industry have been a subject of intense debate and criticism in scholarly circles as well as in the mainstream media. Some have argued that garment production provides much-needed employment opportunities while others have posited that these jobs result in social downgrading. Yet, much still remains unknown about power dynamics, institutions, and actors at the base of global garment supply chains. Interestingly, these local-level networks of social relationships and actors are manifested in distinctive ways across socially contentious and spatially bound geographical settings referred to as local labor control regimes. These interlinkages are further complicated by a diverse workforce in which social control by employers and workers\u2019 influence over the local labor control regime become functions of workers\u2019 socioeconomic contexts (i.e., positionality). Nonetheless, most analyses of labor control regimes are rather limited in scope in primarily accounting for the role of firm/employer practices in shaping local labor control regimes, while relatively overlooking that of labor agency. Moreover, the garment workforce has often been perceived as either feminized or migrant at a time, resulting in intersectional analyses of mutually interacting social identities \u2013 such as gender and internal migration status \u2013 enjoying scant scholarly attention at best. Focusing on internal migrant workers in an export-oriented garment industrial setting in southern India, this dissertation makes important contributions while pushing the frontiers of industrial relations scholarship, particularly within the context of global supply chains, in several ways. First, it adopts an intersectional approach towards labor-capital contention and highlights how worker subordination is reproduced in this relationship as it relates to workers\u2019 intersectional social identities, specifically internal migration status and gender. Put differently, it shows that employers leverage different social identities of workers in ways that reproduce workforce segmentation at the globalized garment workplace thereby hindering labor contestation. Second, it demonstrates how internal migrant women exercise agency \u2013 including non-collective and non-confrontational \u2013 and influence the local labor control regime. Third, it presents one of the first studies to document internal migrant worker organizing extensively. In doing so, it addresses a range of migrant vulnerabilities and builds on existing work, which has highlighted union efforts for organizing locally based workers and international migrants but not internal migrants as such. Fourth, it underscores a relatively underresearched process of grassroots union organizing of internal migrants in an emerging context and complements the evolving scholarship in this domain. Fifth, it brings to light the challenges emanating from within unions that workers with gendered and migrant identities may face toward effective union participation. These impediments exacerbate preexisting low prospects for effective mobilization and undermine labor representation at the garment workplace. From a practical standpoint, this dissertation also highlights unique power relationships between workers \u2013 particularly internal migrant workers \u2013 and organizations such as employers and unions at the local level in global supply chains. It uncovers critical implications for policy formulation pertaining to labor rights targeted at highly vulnerable workers; unpacks strategies for organizing a hitherto underacknowledged worker category of internal migrants; and brings forth equity issues within the labor movement so important for active union participation and mobilization. In summary, this work is an essential consolidated complement to the existing yet rather partial grassroots analyses of labor-capital power relationships in globalized industrial contexts.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
NEUROTENSIN-EXPRESSING LATERAL HYPOTHALAMIC NEURONS ALLEVIATE PAIN VIA NEUROTENSIN RECEPTOR SIGNALING
No full textThesis (Ph.D.)--Michigan State University. Neuroscience - Doctor of Philosophy, 2024Chronic pain and obesity frequently occur together. An ideal therapy would alleviate pain without weight gain, and most optimally, could promote weight loss. The neuropeptide neurotensin (Nts) is implicated in reducing weight and pain, but the endogenous mechanisms underlying this physiology were unknown. We previously showed that activating lateral hypothalamic area neurons expressing Nts (LHANts neurons) suppresses feeding and promotes weight loss. Here we hypothesized that LHANts neurons are an endogenous source of Nts that can provide antinociception, and hence, that activating LHANts neurons would alleviate pain dependent on Nts signaling via NtsRs. We first used Designer Receptor Exclusively Activated by Designer Drug (DREADDs) to activate LHANts neurons in normal weight and diet-induced obese (DIO) NtsCre mice. Activating LHANts neurons had no effect on thermal pain and mechanical responses in na\uefve normal weight mice. By contrast, both spared nerve injury- (SNI) and complete Freund\u2019s Adjuvant (CFA)-induced mechanical hypersensitivity was completely reversed by DREADD ligand clozapine N-oxide (CNO)-mediated stimulation of LHANts neurons compared to control na\uefve normal weight mice. Similarly, activating LHANts neurons had no effect on thermal pain responses in DIO mice. By contrast, obesity-induced pain hypersensitivity as well as CFA-induced inflammatory pain was completely reversed by CNO-mediated activation of LHANts neurons compared to VEH control. However, pretreatment with the brain permeable Nts receptor pan-antagonist SR142948 (1mg/kg, i.p, 30 min before VEH/CNO) blocked CNO-mediated analgesia, indicating that LHANts neurons alleviate chronic pain in an Nts-dependent manner. Furthermore, Nts deletion from the LHA by injecting AAV-Cre into the LHA of Ntsflox/flox mice further exacerbated hyperalgesia in DIO mice compare to normal weight mice. Taken together these data suggest that augmenting signaling via LHANts neurons may be a common actionable target to treat comorbid obesity pain.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
Improved search for CP-violation in ortho-positronium decay
Get PDFThesis (Ph.D.)--Michigan State University. Physics - Doctor of Philosophy, 2024The observed baryon asymmetry of the universe requires combined Charge Parity () violation, likely more than the Standard Model contains. Simultaneously, the scarcity of antimatter makes direct tests of -violation difficult to perform in a laboratory, and many tests search for time-reversal violation () and use combined -symmetry to equate this with -violation. Direct searches involving matter and antimatter are robust and insensitive to false signals like final state interactions. Positronium is a bound state of an electron and a positron, and can be copiously produced in a laboratory. This motivates the design and construction of a dedicated detector array to search for -violation in the 3- decay of ortho-positronium, with a target sensitivity of for the measured asymmetry, a factor of 10 improvement on current limits.The experiment will require tensor polarized positronium, which can be achieved by utilizing a magnetic field. The sensitivity target will require high statistics and large detector acceptances. To these ends the array will feature three rings of -detectors with 16 crystals in each ring. The detector array and all readout electronics will be constructed to fit within the warm bore of the FRIB Positron Polarimeter magnet. The detector geometry and placement were studied in Monte-Carlo simulations in order to optimize the array for this specific experiment. This allowed optimization of detector size, shape, array geometry, and energy and multiplicity cuts.Extensive tests of the crystal shape and geometry were performed, these characterized and removed a geometric light collection distortion. A test stand for optimization of positronium formation was constructed. Tests of multiple powders showed that using chunks of silica-aerogel could achieve a lifetime of 135 ns, and up to 40\% formation fraction. This was then placed in a three crystal demonstrator to prototype the online DAQ. The three crystal and start detector combination was able to remove backgrounds and extract the continuous 2-D energy distribution of ortho-positronium decay. The direct comparison of measured count asymmetries with theory motivated quantities (Lagrangian parameters, mixing coefficients, etc.) is non-trivial, and cannot be done in a model-independent way. A detailed discussion of removal of detector acceptances and efficiencies is presented in the context of a specific model. This further required extension of the theory analysis to incorporate the effects of a static magnetic field, which induces non-trivial time dynamics of the different angular distributions. This clarifies some inconsistencies in the literature on the time dependence of the asymmetry in a magnetic field. The detector array is under construction and will be able to reach the target sensitivity with 35 days of continuous runtime.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references
COMPUTATIONS OF COMBINATORIAL MULTIFILTERED LINK FLOER COMPLEXES
Get PDFThesis (Ph.D.)--Michigan State University. Mathematics - Doctor of Philosophy, 2024We consider how to effectively compute the combinatorial multigraded link Floer homology ofknots and links, then implement it. The goal being to compute the invariant for knots and links for which it is unknown, and further develop the algorithm for its production. We review a traditional description of knot Floer homology and motivate it. Then we move to the combinatorial description of the theory known as grid homology. From there we consider and implement an algorithm leveraging some changes in perspective and tools afforded by modern computing. Finally, included at the end is a compilation of some standard properties of the invariant for examples computed using the resulting program. From the resulting directed graphs we extract the Poincar \u301e polynomial along with some properties of the invariant for each sample knot.Description based on online resource. Title from PDF t.p. (Michigan State University Fedora Repository, viewed ).Includes bibliographical references