2020-
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Item Open Access The application of Agile to large-scale, safety-critical, cyber-physical systems(Colorado State University. Libraries, 2025) Yeman, Robin, author; Malaiya, Yashwant, advisor; Adams, Jim, committee member; Simske, Steve, committee member; Herber, Daniel, committee member; Arneson, Erin, committee memberThe increasing complexity of large-scale, safety-critical cyber-physical (LS/SC/CP) systems, characterized by interconnected physical and computational components that must meet stringent safety and regulatory requirements, presents significant challenges to traditional development approaches. Traditional development approaches, such as the waterfall methodology, often struggle to meet adaptability, speed, and continuous assurance demands. This dissertation explores the feasibility of applying and adapting Agile methodologies to LS/SC/CP systems, focusing on challenges like regulatory compliance and rigorous verification, while intending to prove benefits such as improved risk management and faster development cycles. Through case studies and simulations, this research provides empirical validation of Agile's effectiveness in this domain, contributing a framework for adapting Agile practices to meet the unique demands of LS/SC/CP systems. Employing a mixed-methods approach, the research comprises five key components. First, a systematic literature review (SLR) was conducted to assess the current state of Agile adoption in LS/SC/CP environments. Second, a comparative analysis of the top 10 Agile scaling frameworks was performed to evaluate their suitability for LS/SC/CP system development. Third, a survey of 56 respondents provided both quantitative and qualitative insights into industry trends, adoption patterns, and Agile's impact on LS/SC/CPs. Fourth, 25 one-on-one interviews with industry practitioners further explored the challenges, benefits, and enablers of Agile adoption in these environments. Finally, lifecycle modeling (LML) using Innoslate was utilized to develop a fictional case study, modeling the development of a mid-size low Earth orbit (LEO) satellite using both NASA's Waterfall approach (Phase A-D) and an Agile approach with a series of Minimum Viable Products (MVPs). Findings reveal that Agile methodologies, when adapted for LS/SC/CP systems, enable accelerated development cycles, reducing development time by a factor of 2.5 compared to Waterfall while maintaining safety and regulatory compliance. A key contribution of this study is the introduction of a Continuous Assurance Plugin, which integrates continuous validation within Agile's iterative processes, effectively addressing compliance and safety requirements traditionally managed through phase-gated reviews in Waterfall. Additionally, this research provides: 1. Empirical validation of Agile Scaling Frameworks and their suitability for delivering LS/SC/CP systems. 2. Quantitative and qualitative analysis of Agile's current state and impact in LS/SC/CP environments. 3. Evaluation of key enabling technologies such as Model-Based Systems Engineering (MBSE), Digital Twins, and Continuous Integration/Continuous Deployment (CI/CD) that facilitate Agile adoption for LS/SC/CP systems. This dissertation advances the understanding of Agile's role in LS/SC/CP system development, providing actionable insights and practical adaptations for organizations seeking to implement Agile in complex, safety-critical domains.Item Open Access Controlled testing of next generation leak detection and quantification solutions to evaluate performance and develop consensus assessment metrics(Colorado State University. Libraries, 2025) Ilonze, Chiemezie Okechukwu, author; Windom, Bret C., advisor; Zimmerle, Daniel, advisor; Olsen, Daniel B., committee member; Levin, Ezra, committee member; Pierce, Jeffrey, committee memberReducing methane emissions, a potent short-term climate forcer, is critical for mitigating global warming. The oil and gas (O&G) industry is a major source of anthropogenic methane emissions, and regulations in the U.S. and Canada mandate leak detection and repair (LDAR) programs to mitigate these emissions. Traditional LDAR methods, which includes manually surveying O&G assets with handheld optical gas imaging (OGI) cameras or portable organic vapor analyzers, can be costly and labor-intensive given the vast spatial extent of O&G facilities. However, emerging, next-generation leak detection and quantification (LDAQ) solutions promise a more cost-effective alternative but must demonstrate equal or superior emissions mitigation potential to gain regulatory approval. Standardized controlled testing is essential for verifying this equivalence, yet no widely accepted framework currently exists to achieve this goal. This study evaluates and improves the first known standardized controlled testing protocols designed to address this gap. Two test protocols were developed for the two broad categories of LDAQ solutions: continuous monitors, which operate autonomously over extended durations, and survey solutions, which function over shorter durations with human supervision. These protocols, developed through multi-stakeholder collaboration, were used to test 29 LDAQ solutions (some tested multiple times) at the Methane Emissions Technology Evaluation Center (METEC). METEC is an 8-acre outdoor controlled testing facility that simulates methane emissions from North American onshore O&G equipment. Each survey solution and continuous monitor was tested for a minimum of 3 days and 11 weeks, respectively. Tested controlled release rates were up to 7100 g CH4/h for continuous monitors and 2100 g CH4/h for survey solutions. Key performance metrics, including probability of detection (POD), localization accuracy and precision, quantification accuracy, and survey times, were assessed. Seven solutions were retested 3 to 13 months after their initial tests to examine performance changes over time. Results showed that no single LDAQ solution or solution category achieved optimal performance across all the metrics evaluated. For continuous monitors, only two solutions achieved 90% POD within the tested range, failed to detect ≤ 40% of the controlled releases, and had ≤ 40% of their reported detections classified as false alerts. Camera- and laser-based continuous monitors demonstrated the highest emissions source localization accuracy, with most of them attributing ≥49% of their detection reports to the correct emission source. Quantification uncertainty varied widely, with solutions underestimating and overestimating actual emission rates by factors up to 50 and 46, respectively. For survey solutions, handheld OGI cameras exhibited better accuracy and repeatability in detecting and localizing small fugitive emissions compared to mobile (automobile-/drone-based) survey solutions, although the latter completed emission surveys faster. Additionally, performance improvements were observed with repeated testing, emphasizing the likely importance of regular, independent, and comprehensive evaluations in advancing LDAQ solutions. Findings from these controlled tests, combined with stakeholders feedback and insights from parallel field testing, informed the revision of the protocols to better reflect the application of LDAQ solutions at real O&G facilities. Study findings demonstrates that integrating multiple solutions can complement the limitations of any individual or category of LDAQ solutions. Continuous monitors and automobile-/drone-based survey LDAQ solutions can rapidly detect and narrow-down sources of emissions, enabling targeted follow-up investigations with handheld LDAQ survey solutions. In general, this work contributes significantly to efforts aimed at accelerating regulatory approval and adoption of next-generation LDAQ solutions for methane emissions mitigation through transparent and rigorous controlled testing.Item Open Access A complex of interactions in rare-earth based quantum honeycomb magnets(Colorado State University. Libraries, 2025) Treglia, Andrew, author; Gelfand, Martin, advisor; Neilson, James, advisor; Chen, Hua, committee member; Prieto, Amy, committee memberQuantum spin liquids (QSLs) represent an exotic state of matter characterized by long-range quantum entanglement and fractionalized excitations. Although predicted theoretically by models such as the Kitaev honeycomb model, experimentally verifying these states in real materials remains a significant challenge in condensed matter physics. This dissertation investigates the magnetic interactions in rare-earth honeycomb materials as potential candidates for realizing QSLs, with a focus on the exchange mechanisms governing their magnetic properties. Through a combination of magnetization, heat capacity, and inelastic neutron scattering experiments, this work systematically explores the magnetic phase behavior of Yb2Si2O7 and ErCl3, two rare-earth compounds with effective spin-1/2 degrees of freedom on geometrically frustrated lattices. The first part of this dissertation examines Yb2Si2O7, which exhibits field-induced quantum phase transitions. Magnetization measurements reveal strong anisotropy consistent with spin-orbit coupled physics, while neutron diffraction and inelastic spectroscopy provide insight into the formation of a Bose-Einstein condensate (BEC) of triplons. However, the absence of staggered magnetization in field-dependent neutron scattering data challenges prior theoretical models and suggests a more complex underlying exchange mechanism. The second part of this work focuses on ErCl3, a material whose honeycomb lattice structure and strong single-ion anisotropy make it a promising candidate for realizing bond-dependent exchange interactions. Single-crystal neutron scattering experiments, performed in a controlled air-free environment, reveal deviations from conventional isotropic exchange, indicating the presence of anisotropic interactions. A systematic analysis of spin wave excitations enables the extraction of exchange parameters, offering experimental constraints for theoretical models describing Kitaev-like interactions in this system. By integrating experimental results with theoretical models, this dissertation advances the understanding of rare-earth-based quantum magnets. The findings underscore the importance of strong spin-orbit coupling and crystal field effects in stabilizing anisotropic exchange, while highlighting key challenges in the experimental verification of QSL behavior. These results provide critical insights for the ongoing search for materials that host quantum spin liquid states and topological excitations, paving the way for future investigations into the realization of quantum matter in real materials.Item Embargo The neuroinflammatory nexus: glial dysfunction in the pathogenesis and therapeutic targeting of neurodegenerative and neurodevelopmental disorders(Colorado State University. Libraries, 2025) Risen, Sydney J., author; Moreno, Julie, advisor; Tjalkens, Ronald, committee member; LaRocca, Tom, committee member; Nordgren, Tara, committee memberChronic neuroinflammation is increasingly recognized as a fundamental driver of both neurodegenerative and neurodevelopmental disorders, linking immune dysregulation, glial dysfunction, and disease progression. In neurodegenerative protein misfolding disorders (NPMDs), including Alzheimer's disease, Parkinson's disease, and prion diseases, sustained microglial and astrocytic activation exacerbates protein aggregation, synaptic dysfunction, and neuronal loss, accelerating cognitive decline. Similarly, in neurodevelopment, aberrant inflammatory signaling during critical windows of brain maturation impairs synaptic formation, alters neurotransmitter systems, and predisposes individuals to long-term cognitive and behavioral deficits. Despite distinct manifestations, both disease categories share a pathological feature: a maladaptive neuroimmune response disrupting neural homeostasis. While neuroinflammation is widely implicated in these disorders, defining its molecular mechanisms, identifying therapeutic targets, and understanding environmental contributions remain critical research needs. This dissertation begins to address these gaps by investigating neuroinflammation as both a therapeutic target in NPMDs and a mechanistic link between environmental exposures and neurodevelopmental disruption. The first investigation evaluates SB_NI_112, a novel brain-penetrant RNA-based therapeutic designed to selectively inhibit NF-κB and NLRP3 inflammasome pathways, key regulators of glial activation and chronic neuroinflammation. Pharmacokinetic and biodistribution studies in small- and large-animal models were first conducted to assess SB_NI_112's CNS penetration and safety. These studies confirmed robust brain bioavailability (~30%) and a favorable safety profile, supporting its viability for therapeutic application. Following these findings, SB_NI_112 was tested in a murine prion disease model, where treatment significantly reduced microglial and astrocytic activation in disease-relevant brain regions, preserved hippocampal neurons, and mitigated neurodegeneration. These neuroprotective effects corresponded with improved cognitive performance in novel object recognition tasks, indicating functional preservation despite ongoing prion pathology. Notably, SB_NI_112 treatment extended survival, reinforcing inflammasome inhibition as a viable therapeutic strategy for NPMDs. These findings provide strong proof-of-concept for targeting neuroinflammatory pathways to slow disease progression and preserve cognitive function in neurodegenerative protein misfolding disorders. The second investigation examines the role of environmental neurotoxicants in triggering neuroinflammation and impairing neurodevelopment. Using a juvenile mouse model, this study demonstrates that chronic low-dose manganese (Mn) exposure (50 mg/kg via drinking water) first alters gut microbiome composition, depleting the relative abundance of beneficial Lactobacillaceae, and increasing the relative abundance of pro-inflammatory Erysipelotrichaceae, contributing to gut-brain axis dysfunction. These microbial shifts coincide with significant gliosis in the enteric nervous system, suggesting early neuroimmune activation at the gut interface. This inflammatory response extends to the brain, where widespread microglial and astrocytic activation is observed alongside disruptions in neurotransmitter production and metabolism, including altered dopamine and serotonin homeostasis. Functionally, these neuroimmune and neurochemical disruptions correspond with changes in behavior, indicating impaired neural processing. The presence of inflammatory lesions in the intestinal lining further implicates gut inflammation as a mediator of Mn-induced neurodevelopmental deficits. These findings highlight the systemic impact of Mn exposure, reinforcing the link between environmental toxins, neuroinflammation, and behavioral dysregulation. Together, these studies further support the growing body of evidence that neuroinflammation is a primary driver of neurological disease rather than a secondary consequence, reinforcing the need for targeted neuroimmune interventions. By examining shared inflammatory features across NPMDs and environmentally induced neurodevelopmental disruptions, this work provides additional insight into how glial dysfunction contributes to neurological pathology. These findings support the continued development of neuroimmune-modulating therapeutics, emphasize early intervention, and highlight the importance of environmental risk mitigation. By bridging molecular, pharmacological, and environmental perspectives, this dissertation contributes to the broader understanding of neuroinflammation in disease progression, challenging traditional distinctions between neurological disorders and providing a foundation for future studies. The implications extend beyond basic science, offering translational potential for clinical intervention, public health strategies, and regulatory policies to reduce the burden of neuroinflammatory disease.Item Open Access Responsible exits and social outcomes of conservation philanthropy(Colorado State University. Libraries, 2025) Le Cornu, Elodie, author; Gruby, Rebecca L., advisor; Betsill, Michele M., committee member; Lavoie, Anna, committee member; Basurto, Xavier, committee memberEnvironmental philanthropy is witnessing unprecedented growth. In recent years, several foundations have invested billions of dollars to solve environmental issues such as biodiversity loss, climate change, and sustainable resource management (Betsill et al., 2021; Mufson, 2021; Greenfield, 2021). Ocean philanthropy has seen a particularly significant increase, with ocean conservation funding more than doubling over the past decade, exceeding USD 1 billion in 2022 (CEA, 2023). Within this landscape, small-scale fisheries are estimated to receive $10-$23 million annually (Rare, 2016). While philanthropic funding has contributed to significant progress in conservation, there is growing scrutiny regarding its efficiency, legitimacy, and the concentration of power in the hands of a few billionaires influencing public policies. This dissertation answers the growing calls for opening the black box of philanthropy (Rogers, 2015; Goss, 2016; Skocpol, 2016; Betsill et al., 2021; Gruby et al., 2021). Specifically, a critical aspect of conservation philanthropy that remains unexplored is the process of exiting and the consequences for grantees and communities. The impetus for the three manuscripts that make up this dissertation is the Packard Foundation's exit from the Western Pacific region after twenty years of funding marine conservation. Through a multi-scalar approach, this dissertation explores responsible exits and the social outcomes of conservation philanthropy. Case studies across global, regional/national, and local governance scales contribute a comprehensive analysis that is theoretically informed and empirically grounded of the way foundations navigate exits and the social outcomes of the projects they fund. This dissertation moves beyond the binary critiques of foundations as "good" or "bad" and takes a solution-oriented approach while also engaging in critical and reflexive research. This dissertation is grounded in two important fields: environmental governance and environmental philanthropy. I argue for greater shared learning between these two fields to advance conservation philanthropy's understanding and practice. Specifically, environmental philanthropy can benefit from the existing conceptual frameworks, empirical research and methodologies of environmental governance, while environmental governance should recognize philanthropic foundations as influential actors that need more research attention. Foundations often lack a clear framework to guide their exit strategies in a responsible way, sometimes leading to poorly executed exits which can leave grantees and the work they do struggling to sustain conservation efforts. The second chapter fills that gap by developing an exit typology and a set of best practices, offering guidance for funders who navigate exits. The key takeaway of this chapter is that exits should not be an afterthought but an integral part of the decision-making process, ideally planning from the very start to ensure long-term sustainability. But how are exits experienced on the receiving end? Chapter three explores the exit viewpoints of ocean conservation practitioners, including grantees, who experienced the Packard Foundation exit in Fiji and Palau. This Chapter reveals that viewpoints were diverse (i.e., optimistic, pessimistic, ambivalent, and apathetic) and shaped by a combination of rationales. While optimistic viewpoints were mostly linked to Packard implementing exit best practices that relate to the principles and administration and management categories of the responsible exit framework (Chapter 2), pessimistic viewpoints were linked to challenges related to the sustainability category of the framework, which are more systemic in nature. This Chapter reasserts that exit best practices are key to conducting a responsible exit and that some of these practices must be addressed by foundations at both the field and individual organizational levels. The fourth Chapter examines how philanthropic funding affects communities. This Chapter examines the social outcomes of conservation philanthropy through the case study of a Packard-funded small-scale fisheries project in Palau. Using Photovoice, a participatory research method that centers the voices and experiences of fishers, this Chapter reveals a mix of positive and negative outcomes. A key takeaway is the importance of strong community engagement in the design and implementation of philanthropic-supported conservation projects. Growing critiques of current models of giving must be taken seriously. Changes are needed to ensure that philanthropy operates in a responsible and just manner for both people and the environment by being more transparent, inclusive, and accountable to the communities it directly supports. This dissertation informs these conversations with an empirical analysis that centers the perspectives of grantees and communities affected by philanthropic-funded projects.Item Open Access Improvement of oxide ceramic materials via cation substitution for thermionic emission applications: connecting cation characteristics to changes in atomistic structure and properties(Colorado State University. Libraries, 2025) Fisher, Liam Eugene, author; Ma, Kaka, advisor; Weinberger, Chris, committee member; Neilson, Jamie, committee member; Bandhauer, Todd, committee memberMy research aimed to improve oxide ceramic materials for thermionic emission applications through strategic cation substitution, focusing on enhancing material properties like thermal stability and electrical conductivity. In thermionic emission applications, low work functions and high thermal resilience are essential material properties for efficient electron emission under high temperatures. Two oxide-based material systems, mayenite electride and strontium vanadate, were selected in the present work, because of their promising low work function, reasonable thermal stability, and economical costs of precursors. But both materials require improvements to realize or increase their applicability in thermionic emission technologies. Moreover, these two material systems possess distinguishing lattice structures from each other and utilize different mechanisms for low work function. Thus, in-parallel investigation into and comparison of the results from these two types of oxide ceramics provide fundamental insights into the interplay between the atomistic structure and cationic substitution. A critical objective of this research is to discover how various cation substitutions affect the lattice structure and how these structural changes subsequently modify key material properties for the thermionic emission application. Different cations were substituted at select sites in mayenite electride and strontium vanadate structures, individually and in dual combinations, to assess their effects on thermal stability and electrical conductivity. The hypothesis was that substituting smaller cations at particular atomic sites might increase thermal stability by altering the lattice parameters, bonding environment, and electron density. The study also investigated how dual substitutions might synergize beneficial effects from individual cations, with a focus on combinations that can potentially balance thermal stability and electrical conductivity. To characterize structural modifications, this research employs Rietveld refinement of X-ray diffraction data to conduct detailed analysis of lattice parameter adjustments and cation disorder, providing insight into the structural intricacies induced by specific substitutions. Additionally, thermogravimetric and electrical conductivity analyses reveal trends in the change of oxidation resistance and conductivity that align with anticipated impacts of certain cations. Results suggest that substituting smaller cations into mayenite lattice significantly increases oxidation onset temperature. In strontium vanadate, substitutions at the A- and B-sites have limits to stability as the material drifts further from the ideal tolerance factor of one, with critical implications for phase stability and oxidation behavior. The calcium substitute for strontium led to a vast improvement in both thermal stability (onset of rapid oxidation increased to a temperature > 1050°C) and electrical conductivity (σ > 3000S/cm). The key findings from this work demonstrate that tailored cation substitutions can substantially improve the key properties of oxide ceramics, offering pathways for material optimization for thermionic applications in harsh environments.Item Open Access Emergent topological phenomena in low-dimensional systems induced by gauge potentials(Colorado State University. Libraries, 2025) Winblad, Aidan, author; Chen, Hua, advisor; Eykholt, Richard, committee member; Gelfand, Martin, committee member; Pinaud, Olivier, committee memberIn this dissertation we discuss how gauge potentials can be used as a key ingredient for inducing topological phase transitions in condensed matter systems, such as conductors, insulators, and superconductors. The first chapter covers some important background physics: Maxwell's equations, gauge invariance, minimal coupling, and Peierls phase, etc. It then presents a review of how one can realize Majorana fermions (MFs) in superconductors and their importance to topological quantum computing. In the end of chapter 1, we give an overview of the basics of Landau levels (LLs) and their relation to the Chern number. Chapter 2 presents a theoretical proposal for inducing topological phase transitions that allow for MFs to be hosted and rotated along the corners of a hollow equilateral triangle, which can serve as a basic building block for topological quantum logic gates. This provides a potential new avenue for achieving a topological quantum computation where a network of interconnected triangular islands allows for braiding of MFs. In chapter 3 we show using Floquet theory and high-frequency expansion, that oblique incident, circularly polarized light can give rise to spectral features analogous to Landau levels in the quantum Hall effect (QHE), where the effective magnetic field is related to the electric field of the laser light. Outside of having the electric field as a useful parameter for achieving a QHE device, this finding enables us to explore non-equilibrium systems exhibiting topological phenomena in the absence of spatial periodicity. Chapter 4 concludes and discusses further implications of the work in this dissertation.Item Open Access Influence of orchard factors on apple harvest quality and postharvest performance(Colorado State University. Libraries, 2025) El Zabbati, Hanan Mustafa, author; Minas, Ioannis, advisor; Bauerle, Bill, advisor; Prenni, Jessica, committee member; Bunning, Marisa, committee memberFocusing on both preharvest and postharvest elements, this study investigates how crop load affects apple growth, development, and quality. A worldwide important fruit crop, apples have been grown for over two thousand years, with more than 10,000 types known. Several elements affect apple quality, including environmental factors, genetic factors, and orchard management techniques. The impacts of crop load were investigated on both physiological and metabolomic features, hence stressing its significance as a main factor of ultimate apple fruit quality. The study underlines how apple quality is affected by preharvest variables and how suitable postharvest handling can maintain this quality over storage, hence encouraging more apple consumption. Current regulation and consumer demand provide high economic value for fruits with superior sensory and nutritional qualities. Improvement of apple fruit quality is impossible postharvest. Hence, optimum apple quality at harvest and during postharvest and subsequent, consumer satisfaction, is achievable through understanding the influence of preharvest factors. A large-scale study on the effect of crop load on 'Gala' fruit growth and development and on harvest internal quality and maturity was performed. Hand thinning was used to achieve three crop load treatments: heavy load (978 fruit/tree), commercial load (598 fruit/tree), and light load (380 fruit/tree) that were compared to unthinned trees (1614 fruit/tree). Parameters studied were yield, fruit size during growth and development and at harvest, fruit red overcolor blush, starch index, flesh firmness (FF), soluble solids concentration (SSC), dry matter content (DMC), index of absorbance difference (IAD), return bloom and fruit set (next season). Non-destructive models that utilize visual to near infrared spectroscopy (Vis-NIRS) were used to predict internal quality in terms of DMC, SSC and IAD. Apple thinning decreased fruit yield, increased fruit size, DMC, and SSC, improved fruit red overcolor blush and advanced fruit maturity based on IAD. However, it did not affect the starch index and FF. Vis-NIRS technology accurately estimated DMC and SSC at 729-935nm, and maturity based IAD. Additionally, IAD did not correlate with FF but described better fruit physiological maturity. Non-destructive technologies that predict internal fruit quality and maturity are powerful tools that provide a better understanding of the effect of pre-harvest factors on apple fruit quality. In terms of postharvest performance, fruits coming from distinct crop load management treatments were treated or not with 1-methylcyclopropene (1-MCP, 1000 μl 1-1, 24 h, 0o C) an ethylene action inhibitor and known for its effect on prolonging apple fruit quality. Following pre-storage treatment or not with 1-MCP apples coming from heavy, commercial, light crop loads and unthinned trees were cold stored (0oC, 95%, RH) for up to 3 or 7 months. After cold storage fruits were transferred at room temperature (20oC, 90% RH) to simulate retail market conditions and apple ripening was characterized immediately at 0, 4 and 8 days. Collectively, crop load and 1-MCP significantly affected apple fruit storage performance. Fruit coming from lighter crop loads had increased levels of SSC during postharvest ripening due to higher DMC and expressed significantly lower softening rates during storage potentially because of increased carbohydrates pool (DMC and SSC) that potentially correlate with delayed deterioration. Treatment with the 1-MCP through inhibition in respiration and ethylene production blocked fruit ripening, retained higher DMC and SSC levels, and delayed softening and loss of titratable acidity (TA) during postharvest compared to untreated fruits. These results are of high importance for the apple industry as they demonstrate that proper preharvest management could lead to robust postharvest performance.Item Embargo Black feminist technosocial roleplay: exploring visual media representations of Black women's complex relationship with authoritative power(Colorado State University. Libraries, 2025) Bollinger-Deters, Aaunterria, author; Arthur, Tori, advisor; Wolfgang, David, advisor; Famulari, Umberto, committee member; Attai, Nikoli, committee member; Snodgrass, Jeffrey, committee memberUsing Black Feminist Technosocial Roleplay (BFTR) this study revealed the ways in which Black women are represented in visual narratives characterized by authoritative power as well as examining how Black women's relationship with violence can be transfigured in liberatory ways. The critical technocultural discourse analysis of 15 'viral murder videos', 2 'ebony public disgrace' films, and 2 'ebony evolved fights' as well as the examination of 121 viral murder video online surveys, 2 semi-structured interviews with Black women gamers, and a Black feminist gaming autoethnography revealed a.) rehumanized representations of Black women when they control their image, b.) extended public social scripts into technologically mediated fantasy roleplay, c.) violence as a main component of fortifying Black women in public memory, and d.) the cathartic/empowering ways in which video game roleplay can be utilized to reterritorialize Black women's public social roles, especially their proximity to and employment of authoritative power and violence. The analysis also showed how Black women's self-determined presentation and self-valuation is often imperfect, messy, and in some ways monstrous, yet these are still avenues of representation worthy of conscientious study. Additionally, data implications, future recommendations, and research limitations were also discussed in depth.Item Embargo Coping strategies among food insecure households above and below SNAP eligibility guidelines in a high cost of living region(Colorado State University. Libraries, 2025) Altares, Ana Maria, author; Mueller, Megan P., advisor; Bellows, Laura L., committee member; Cleary, Rebecca, committee member; Chennault, Carrie, committee memberThis study explores how households in a high cost-of-living rural region navigate food-insecurity. We examine differences in coping strategies among households with income above and below 130% Federal Poverty Level (FPL) and highlight factors influencing food access among Hispanic/Latino households using a community-based participatory research (CBPR) and multimethod approach. First, a survey of 1,021 food-insecure adults above and below 130% FPL was conducted from December 2022 to March 2024, assessing the extent to which households relied on charitable food assistance and engaged in economic tradeoffs between food and other basic needs. Generalized ordinal logistic regressions analyzed differences between income groups. Second, a photovoice study with six Hispanic/Latino participants used documentary photography and focus groups to document food insecurity experiences through participant narratives and photographs. Participatory content analysis identified key factors influencing food access and navigating food insecurity. Survey findings indicated that participants above 130% FPL were more likely than those below to rely on food pantries (OR = 2.56), soup kitchens (OR = 2.00), and other charitable food sources (OR = 1.44) for the majority of their food. They also engaged in tradeoffs with medicine (OR = 1.65), utilities (OR = 1.30), transportation (OR = 1.21), childcare (OR = 1.18), and education (OR = 1.43) more often. Photovoice findings revealed participants' perceptions around food insecurity including lack of affordable foods and disparities in food access, a regional emphasis on production of grain over local produce which contributed to increased food prices, and local inequities prioritizing tourism over year-round residents. Participants relied heavily on food assistance to reduce hunger and provide additional financial support for food. They also engaged in acts of mutual aid such as volunteering and connecting others in need to food assistance resources as a way to give back to their own communities. The importance of family, culture, and health were also identified as important influences on food access. Households in this high cost-of-living region cope with the experience of being food insecure through both structural and community-based strategies. Those above 130% FPL rely heavily on charitable food assistance and economic tradeoffs, while Hispanic/Latino households employ social networks and cultural resilience. These findings highlight the need for policies and interventions that address food insecurity holistically, considering economic constraints, cultural preferences, and systemic barriers to equitable food access.Item Open Access Breaking the MF curse: the regulatory role of the Methyl farnesoate – MEKRE93 pathway in crustacean molting(Colorado State University. Libraries, 2025) Bentley, Vanessa Leah, author; Mykles, Donald L., advisor; Garrity, Deborah M., committee member; Montgomery, Taiowa, committee member; Reist, Noreen, committee memberEcdysis, or the active shedding of the exoskeleton, is critical for arthropod growth, development, and/or regeneration of lost or damaged appendages. The antagonistic interaction between the steroid hormone 20-hydroxyecdysone (20-E) and the sesquiterpenoid juvenile hormone (JH) control insect molting and development, respectively. On the other hand, crustacean molting is primarily regulated through the endocrine crosstalk between 20-E and the neuropeptide molt-inhibiting hormone (MIH). MIH secretion by the X-organ, sinus gland complex (XO) inhibits Y-organ (YO) synthesis of 20-E. Molting is initiated by the decrease in MIH titers thereby allowing increasing 20-E concentrations in the hemolymph. The molting process is divided into different stages where the YO exhibits different phenotypic states: intermolt (IM)– basal, early premolt (EP)– activated, mid premolt (MP)– committed, late premolt (LP)– committed/repressed, ecdysis (E)– repressed, and postmolt (PM)– repressed/basal. The mechanistic target of rapamycin (mTOR) and transforming growth factor beta (TGF-β) signaling leads to YO activation and commitment, respectively. However, the YO transition to- and from- the repressed state is unknown. Methyl farnesoate (MF), commonly referred to as the crustacean JH, is produced by the mandibular organ (MO) and is suppressed by the mandibular organ-inhibiting hormone (MOIH). MF regulates several physiological processes in crustaceans including metamorphosis, development, reproduction, morphogenesis, and molting; however, the underlying mechanism remains unknown and thereby is considered to be "cursed". The differential effects MF has on molting and ecdysteroidogenesis is hypothesized to be regulated through the Methoprene tolerant– Krüppel homolog 1– E93 (MEKRE93) transcriptional cascade. Using bioinformatic approaches, the components of the MF signaling pathway were identified in the European green shore crab (Carcinus maenas) and the blackback land crab (Gecarcinus lateralis) YO transcriptomes, including the MF/JH receptor Methoprene tolerant (Met), the zinc finger transcription factor Krüppel homolog 1 (Kr-h1), Ecdysone response gene 93 (E93), Steroid receptor coactivator (Src), and transcription comediators CREB–binding protein (CBP) and C-terminal–binding protein (CtBP). Additionally, genes encoding for the MF synthetic pathway enzymes were also identified in the YO transcriptomes including 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), farnesoic acid O-methyltransferase (FAMeT), and FAMeT2. Additionally, a FAMeT2 transcript was also identified in the YO and contains an unconventional domain organization compared to annotated FAMeT. Nonetheless, phylogenetic analysis of each gene was overall highly conserved across pancrustaceans (and occaisionally panarthropodans). Furthermore, in vitro assays showed that C. maenas and G. lateralis YOs were responsive to JH-mimics (e.g. pyriproxyfen, fenoxycarb, methoprene, and hydroprene), but not to MF. Taken altogether, these data suggest that the YO can respond to MF and may have its own MF-innate system serving as an autocrine factor to regulate the YO by acting through a MEKRE93 transcriptional network that can be mediated by coregulators.Item Open Access Use of chemical ionization mass spectrometry for study of photochemical properties: ketone photolysis quantum yields(Colorado State University. Libraries, 2025) Berg, Tyson C., author; Farmer, Delphine K., advisor; Ravishankara, A. R., committee member; Sambur, Justin B., committee member; Jathar, Shantanu, committee memberMeasurements of organic radicals produced during organic trace gas photolysis are critical to our understanding of radical budgets throughout the troposphere. This dissertation demonstrates the utility of chemical ionization mass spectrometry for measurements of radical quantum yields in the photolysis of organic trace gases in the laboratory setting. Chapter 2 addresses the development of a coupled chemical ionization mass spectrometer with iodide reagent ions (I-CIMS) and wide band light source instrument design, which was used to measure the quantum yield for CH3C(O) from acetone photolysis, through measurement of CH3C(O)O2. Acetone is the most abundant oxygenated organic gas in the troposphere and its photolysis can account for up to 1/3 of radical production in the upper troposphere. The results from this chapter demonstrate that the I-CIMS can be used for acetone photolysis measurements under conditions of the troposphere. In Chapter 3, the I-CIMS measurements of the CH3C(O) quantum yield in acetone photolysis are expanded to temperatures (223 to 323 K) and pressures (150 to 850 mbar) reflecting the conditions of the troposphere. The measurements are used to parameterize the quantum yield of CH3C(O) for use in models of tropospheric radical production. The parameterization shows that acetone photolysis near the tropopause may be up to 1.4 times slower than previously expected. These are the only measurements of acetone photolysis under tropospheric conditions based on the detection of the dominant radical product, CH3C(O)O2. Chapter 4 explores a new, multiple-reagent ion system with Cl2- as the primary reagent ion (Cl2-CIMS). Cl2-CIMS provides higher sensitivity for small acyl peroxy radicals than achieved with I-CIMS. However, the higher background of Cl2-CIMS leads to higher limits of detection and the uncertainty on multiple reagent ion chemistries makes this system unsuitable for ambient measurements. Cl2-CIMS could be further improved through larger changes to the instrument design than those discussed here, and other novel reagent ion chemistries may be accessible using the multi-step ionization mechanism that produces Cl2-. Chemical ionization mass spectrometry is well-suited to fast, speciated measurements of radicals and is thus useful for measurements of complex photolysis mechanisms, like that of acetone in the troposphere. Further instrument development could improve CIMS sensitivities and limits of detection to organic radicals, expanding its utility to more photochemical systems and ambient measurements of radicals as well.Item Open Access Safeguarding sensitive data: prompt engineering for Gen AI(Colorado State University. Libraries, 2025) Giang, Jennifer, author; Simske, Steven J., advisor; Marzolf, Gregory, committee member; Gallegos, Erika, committee member; Ray, Indrajit, committee memberGenerative Artificial Intelligence (GenAI) represents a transformative advancement in technology with capabilities to autonomously generate diverse content, such as text, images, simulations, and beyond. While GenAI offers significant operational benefits it also introduces risks, particularly in mission-critical industries such as national defense and space. The emergence of GenAI is similar to the invention of the internet, electricity, spacecraft, and nuclear weapons. A major risk with GenAI is the potential for data reconstruction, where AI systems can inadvertently regenerate or infer sensitive mission data, even from anonymized or fragmented inputs. This is relevant today because we are in an AI arms race against our adversaries much like the race to the moon and development of nuclear weapons. Such vulnerabilities pose profound threats to data security, privacy, and the integrity of mission operations with consequences to national security, societal safety and stability. This dissertation investigates the role of prompt engineering as a strategic intervention to mitigate GenAI's data reconstruction risks. By systematically exploring how tailored prompting techniques can influence AI outputs, this research aims to develop a robust framework for secure GenAI deployment in sensitive environments. Grounded in systems engineering principles, the study integrates theoretical models with experimental analyses, assessing the efficacy of various prompt engineering strategies in reducing data leakage, bias, and confabulation. The research also aligns with AI governance frameworks, including the NIST AI Risk Management Framework (RMF) 600-1, addressing policy directives such as Executive Order 14110 on the safe, secure, and trustworthy development of AI. Through mixed-methods experimentation and stakeholder interviews within defense and space industries, this work identifies key vulnerabilities and proposes actionable mitigations. The findings demonstrate that prompt engineering, when applied systematically, can significantly reduce the risks of data reconstruction while enhancing AI system reliability and ethical alignment. This dissertation contributes to the broader discourse on Responsible AI (RAI), offering practical guidelines for integrating GenAI into mission-critical operations without compromising data security. This underscores the imperative of balancing GenAI's transformative potential with the societal need for robust safeguards against its inherent risks.Item Embargo Novel time resolved optical and machine learning methods for label free biomedical imaging(Colorado State University. Libraries, 2025) Mugdha, Arya Chowdhury, author; Wilson, Jesse W., advisor; Bartels, Randy, committee member; Lear, Kevin, committee member; Tobet, Stuart, committee memberRecent advances in multiphoton microscopy are paving the way for better visualization and understanding of intracellular organisms, leading to powerful non-invasive methods for cell and tissue diagnosis. Mitochondrial disorder is a type of disorder that affects the cell's mitochondria and impacts the cell's functionality as a whole. Roughly, these mitochondrial disorders affect between 1 in 6000 and 1 in 8000 live births. These disorders are hard to diagnose as each individual is affected differently by these disorders. Current tools for diagnosis of mitochondrial disorders are either invasive or time consuming in nature. The focus of this dissertation is to develop novel nonlinear optical imaging techniques and algorithms for studying mitochondrial heteroplasmy, one of the markers of mitochondrial disorder where the cells or tissues contain a mixture of healthy and diseased mitochondria. The defects in Electron Transport Chain (ETC) are often the causes behind various mitochondrial disorders. This dissertation aims to develop non-invasive optical methods for studying redox states of Cytochromes in living human cells such as Fibroblasts. Cytochromes are a particular type of Hemeprotein that are comprised of iron porphyrin and are primarily responsible for electron transport within the ETC of Mitochondria. We utilize a two-color visible wavelength pump-probe technique that can roughly detect up to 10-6 absorption changes of the probe beam arising from the approximately 10-15 μm thick live human Fibroblast samples. We detail the technical challenges faced in getting the optical instrument sensitivity to the required level so that Fibroblasts can be imaged with sufficient Signal-to-Noise Ratio (SNR). The major technical challenges that had to be overcome to obtain reasonable pump-probe signal levels from fibroblasts are: (1) minimizing the noise floor of the entire optical instrument so that we are performing shot-noise limited detection using a photodiode; (2) correcting for the focal plane mismatch arising due to chromatic aberration in the axial direction. Additionally, we explore machine learning based algorithms for better data interpretability and visualization of Transient Absorption data. We demonstrate that Hyperspectral Autoencoders, a specific type of Convolutional Neural Networks (CNNs), are able to unmix spectral signatures arising from different molecules in Transient Absorption images of reduced and oxidized muscle fibers. We also devise a novel loss function that takes into account the correlation between different channels of the input image to train the neural network so that the inherent randomness of gradient descent algorithms does not impact the network predictions each time. Furthermore, we explore image-to-image translation neural network algorithms to investigate the possibility of translating Reflectance Confocal Microscopy (RCM) images to Second Harmonic Generation (SHG) images. For this study, we collect co-registered RCM and SHG images from canine oral mucosa muscle tissue with the same Field of View (FOV) and excitation objective. We explore various state-of-the-art deep learning algorithms and evaluate their performance in transforming the RCM modality to SHG modality.Item Embargo The stories of U.S.: nationalisms among college educated white women who voted in the 2016 U.S. presidential election(Colorado State University. Libraries, 2025) Strapko, Noel, author; Hempel, Lynn, advisor; Opsal, Tara, committee member; Lacy, Mike, committee member; McIvor, David, committee memberRelatively recent sociological theories of nationalism understand the nation as variable processes whereby the nation is (re)constructed, albeit in different ways, via nationalism. Nationalism includes nation-oriented meanings and sentiments people embedded within socio-political contexts continually (re)formulate and imbue the nation with, which is how the nation is subjectively (re)created. Research on U.S. nationalism, however, primarily focuses on the subjective content of nationalism while the subjective contextualization of it remains understudied. In addition, although many aspects of nationalism are gendered, how women experience the nation and (re)create it is rarely examined. Addressing these gaps in the literature, this dissertation examines both the subjective content and the contextualization of U.S. nationalisms from the standpoint of college educated white women who voted in the 2016 presidential election. Utilizing in-depth, semi-structured qualitative interviews, I describe the various, yet patterned, ways America and Americans were constructed among interviewees and I examine the how they contextualized their expressions of nationalism. I argue "true" Americans' experiences with the American Dream were used to evaluate America's greatness, or lack thereof, which shaped the national sentiment the interviewees expressed. Findings provide key insight regarding: 1) the relevance of the American Dream for constructions of America, 2) how Americans and "true" Americans were constructed, 3) how gender relations, as well as those concerning other statuses, were used to contextualize nationalisms, 4) why expressions of nationalism can be ambivalent, and 5) how forms of nationalism are intertwined in constructions of American national membership.Item Open Access Design of baffled hydraulic jump stilling basins for dams(Colorado State University. Libraries, 2025) Moses, Dana Wesley, author; Thornton, Christopher, advisor; Crookston, Brian, committee member; Ettema, Robert, committee member; Julien, Pierre, committee member; Rathburn, Sara, committee memberThe hydraulic jump has been studied and used as a primary means of energy dissipation for hydraulic structures for well over a century. By the 1920s and 1930s, baffled hydraulic jump stilling basins were in widespread use as energy dissipators for large dams. These hydraulic jump stilling basins often consisted of toe blocks, a negative step and/or toe curve; one or more rows of baffle blocks; and a solid or dentated end sill. By the 1950's standard design guidance was developed by multiple agencies and universities. A comparison of the standard baffled hydraulic jump guidance illustrates a drastic difference in recommended stilling basin geometry with identical incoming flow conditions. For example, given the same incoming flow conditions, the height of baffle block determined for a U.S. Bureau of Reclamation standard design can be more than twice the block size for a standard outlet works stilling basin determined from US Army Corps of Engineers guidance. The use and/or geometry associated with chute blocks, number of rows of baffle blocks, length of basin, distance to baffle blocks, and end sill geometry have similar discrepancies. The current research includes a systematic physical model evaluation, performing over 400 individual experiments of the most often utilized baffled stilling basin design configurations. These experiments include 15 stilling basin configurations, each being evaluated for six discharge conditions and six tailwater scenarios. In addition, the USACE standard stilling basin configuration was evaluated for the general scour tendencies for discharges below and above the design discharge by means of mobile bed physical modeling. A numbered list of significant findings associated with the current research are provided below. Detailed descriptions of these significant findings and other conclusions and recommendations associated with the research objectives are provided subsequently. 1. The USACE (1992) stilling basin configuration is recommended for incoming Froude Numbers less than 4.5. 2. The Modified Type III stilling basin configuration is recommended for incoming Froude Numbers in the range of 4.5 to 8. 3. The stilling basin length and minimum required tailwater for the USACE (1992) and USBR (1984) can be expressed by unified equations. 4. A toe curve is not recommended for the hydraulic jump basin due to increase in length required and the decrease in jump stability. 5. Intermittent ramps associated with the tapered baffle block configuration are not recommended due to increase in downstream scour potential, decreased tailwater resilience, cost, general lack of observed cavitation damage, and unproven effectiveness in reducing cavitation damage. 6. Macro-scale turbulent structures exiting the stilling basin are the primary phenomenon controlling downstream scour potential. A maximum downstream attack angle of 15-degrees from horizontal was determined for the USACE (1992) stilling basin configuration for incoming Froude Numbers in the range of 3 to 5.Item Embargo Accounting for spatial confounding in large scale epidemiological studies(Colorado State University. Libraries, 2025) Rainey, Maddie J., author; Keller, Kayleigh, advisor; Wilson, Ander, committee member; Guan, Yawen, committee member; Anderson, Brooke, committee memberEpidemiological analyses of environmental risk factors often include spatially-varying exposures and outcomes. Unmeasured, spatially-varying factors can lead to confounding bias in estimates of associations. In this dissertation, I present a comparison of existing and new methods that use thin plate regression splines to mitigate spatial confounding bias for both cross-sectional and longitudinal analyses. I also introduce a metric to quantify the spatial smoothing induced by thin plate regression splines in varying geographic domains. I first investigate cross-sectional data, directly comparing existing approaches based on information criteria and cross-validation metrics and additionally introduce a hybrid method to selection that combines features from multiple existing approaches. Based on a simulation study, I make a recommendation for the best approach for different settings and demonstrate their use in a study of environmental exposures on birth weight in a Colorado cohort. Next, I develop an effective bandwidth metric that quantifies the relationship between spatial splines and the range of implied spatial smoothing. I present an R Shiny application, spconfShiny, that provides a user-friendly platform to compute the metric. spconfShiny can be accessed at https://g2aging.shinyapps.io/spconfShiny/. We illustrate the procedure to compute the effective bandwidth and demonstrate its use for different numbers of spatial splines across England, India, Ireland, Northern Ireland, and the United States. Finally, I extend two cross-sectional methods for spatial confounding adjustment to model longitudinal and time-to-event data. The additional temporal component existing in the data requires an additional selection of which coordinates to use to create thin-plate regression splines basis: the spatial coordinates, temporal coordinates, or both the spatial and temporal coordinates. I demonstrate these methods for mixed models, generalized estimating equation models, and a proportional hazard regression framework. I demonstrate the application of these methods in a study of tropical cyclone wind exposures on preterm birth in a North Carolina cohort.Item Embargo Investigating the relationship between ionizing radiation and neurodegenerative mortality: addressing issues of bias, data pooling, and effect modification(Colorado State University. Libraries, 2025) Zbysinski, Tony J., III, author; Neophytou, Andreas, advisor; Rosecrance, John, advisor; Magzamen, Sheryl, committee member; Wilson, Ander, committee memberBackground Much of the current understanding of the adverse health effects of ionizing radiation (IR) exposure comes from studies of Japanese atomic bomb survivors who experienced acute, high doses of IR. However, these findings may not be generalizable to populations exposed to chronic low doses of IR such as workers and the general population. The U.S. Million Person Study (MPS) was founded to investigate the effects of chronic low dose IR for improved guidance of radiation safety. To address this gap in knowledge, worker cohort studies have been and continue to be conducted to assess the potential risks associated with chronic low dose IR, including neurodegenerative diseases. These studies aim to improve the understanding of IR dose ranges and risks that underly current radiation safety policy. Recent findings underscore a potential increase in risk of neurodegenerative disease from chronic low dose IR which may be of great concern considering the significant burden of such diseases. However, there are inconsistencies in prior research findings regarding the relationship between chronic low dose IR exposure and neurodegenerative disease. Several factors we focus on that can contribute to these inconsistencies are co-exposures to non-radiological substances, lack of power to investigate specific neurodegenerative disease outcomes, and selection mechanisms like the healthy worker survivor effect (HWSE) and competing events. This dissertation research introduces novel techniques to evaluate and improve the internal and external validity of prior and future occupational studies of IR and neurodegenerative-related mortality. The specific objectives of the present study include assessing the role of co-exposures as effect modifiers and/or confounders, enhancing the understanding of the trade-offs of pooling data diverse cohorts together, and addressing selection mechanism concerns. Methods Our first objective focused on assessing the role of co-exposures in the relationship between IR and neurodegenerative-related mortality among workers at the Fernald Feed Materials Plant, referred to as Fernald, and to investigate neurodegenerative-related mortality risk across different job categories. Individual-level, brain IR dose estimates were used alongside co-exposure data from job exposure matrix application to evaluate potential confounding and effect modification. Co-exposures for this evaluation were selected a-priori based on literature review. Cox proportional hazards regression models were used to observe risk of neurodegenerative-related mortality at 10 milligray (mGy) IR brain dose across different groupings of co-exposure status, while logistic regression models were used to calculate odds of neurodegenerative-related mortality across 9 job categories. In our second objective our goal was to evaluate the implications of data pooling in the context of the relationship between IR exposure and neurodegenerative-related mortality by combining data from the Fernald, Linde Ceramics Plant, hereafter called Linde, and Mallinckrodt Chemical Works (MCW) cohorts. The Linde cohort's data was updated to prepare for merging with Fernald and MCW. Extensive data harmonization, such as collapsing continuous IR exposure measurement into a categorical form, was undertaken. Cox proportional hazards regression was again used in data analysis across three distinctive steps that analyzed different aggregation parts between the cohorts, co-exposures of uranium and silica dusts were evaluated. A meta-analysis was also conducted of these same three cohort's individual studies to qualitatively compare overall analogous estimates to the pooled analysis. Lastly, our third objective employed the parametric g-formula to address selection mechanism concerns of HWSE and competing events. The parametric g-formula estimated the effect of hypothetical interventions on the risk of neurodegenerative-related mortality to evaluate the potential for HWSE by reducing IR exposure in hypothetical intervention scenarios. Expert interviews were conducted and supported with literature review to develop feasible hypothetical intervention endpoints of reducing IR exposure with possible real-world explanations including engineering and administrative controls. To investigate competing events, in one approach we modeled a likely competing event, cardiovascular disease (CVD) mortality, and compared cumulative incidence results to another approach without modeling for CVD mortality. Results Aim 1 findings highlighted that occupational exposure to machining fluids may act as an effect modifier of the relationship between IR and neurodegenerative-related mortality. Workers highly co-exposed to machining fluids showed significantly increased risk of neurodegenerative-related mortality at 10 mGy IR brain dose (HR 1.25, 95% CI 1.11, 1.40) compared to the overall baseline estimate (HR 1.01, 95% CI 0.96, 1.06). Additionally, certain job categories such as store and supply services had elevated odds of neurodegenerative-related mortality compared to administrative workers (OR 2.30, 95% CI 0.97, 4.96). Findings in Aim 2 revealed overall results consistent with Aim 1 of no increased risk of neurodegenerative-related mortality at low/moderate IR category (HR 0.95, 95% CI 0.73, 1.24) and high IR category (HR 1.05, 95% CI 0.80, 1.37). There was no evidence of confounding or effect modification by silica or uranium dusts. The meta-analytic estimate of these same cohort's individual studies had a similar summary estimate null finding compared to the pooled analysis finding for high categorical IR (HR 0.95, 95% CI 0.75, 1.20). Results of Aim 3's application of the parametric g-formula indicated that the HWSE may not be a key factor in the relationship between IR and neurodegenerative-related mortality as cumulative incidence (CI) did not change considerably between the natural course (cumulative incidence, 16.99%), engineering control (17.43%), and administrative control (17.14%) interventions in the application modeling for competing events. When comparing approaches that modeled and did not model for competing events, we did find evidence that CVD mortality acts as a competing event for neurodegenerative-related mortality. Conclusions This dissertation found that occupational co-exposures, such as machining fluids, may modify the relationship between IR and neurodegenerative-related mortality. In a pooled analysis of worker cohorts we encountered significant data harmonization challenges that emphasized the importance of careful selection of data pooling candidates and meta-analyses as an alternative to aggregating data for some research questions. Furthermore, the selection mechanism of HWSE may not be a key factor for IR and neurodegenerative-related mortality in Fernald, but CVD mortality appears to act as a competing event to neurodegenerative-related mortality. These findings offer potential explanations and insights into the inconsistencies in prior research of IR and neurodegenerative-related mortality and highlight the need to consider co-exposures, data aggregation approaches, and selection mechanisms. This research contributes by showing the importance of evaluating the role of co-exposures as effect modifiers, providing insights into the goals of multi-cohort pooling efforts by discussing trade-offs of data pooling versus meta-analytic approaches, and exemplified a relatively innovative and novel method of addressing selection mechanism concerns in the field of occupational radiation epidemiology. Future research should focus on replicating these approaches in different circumstances that may alleviate the limitations of the present investigations to continue the overarching goal of best informing radiation safety policy for the general population and modern workforce.Item Open Access Synthetic and spectroscopic investigations of electron spin relaxation(Colorado State University. Libraries, 2025) Moseley, Ian, author; Zadrozny, Joseph M., advisor; Finke, Rick, committee member; Prieto, Amy, committee member; Buchanan, Kristen, committee memberMolecular magnets (also referred to as single molecule magnets (SMMs)), are organometallic complexes which can retain their magnetization in the absence of an applied field. The loss of this magnetization due to environmental interactions is referred to as magnetic relaxation. Due to the small energy gap between electronic spin orientations, maintaining this magnetization typically requires the molecules be held at temperatures approaching absolute zero. This requirement is both costly and impractical for most of the envisioned applications, and as such considerable research efforts have been made to increase the operating temperatures of molecular magnets. This dissertation presents a series of investigations into the magnetic relaxation behavior of molecular magnets incorporating first-row transition metals coupled to adjacent spin centers through electron-electron interactions. Presented herein is a series of investigations which demonstrate a novel method for extending magnetic relaxation in spin-abundant environments, the synthesis and characterization of a low-coordinate iron species as a potential precursor to extended solids, the magnetic properties of a pair of iron-based coordination polymers, and an investigation into the design of electron paramagnetic resonance (EPR) imaging probes using spin forbidden transitions. This research serves as a starting point for future investigations into the control of magnetic relaxation phenomena through synthetic control of electron-electron interactions.Item Embargo Advancing disease surveillance and biosecurity in North American bison (Bison bison): multidisciplinary approaches to bison health monitoring(Colorado State University. Libraries, 2025) Krus, Catherine Bridget, author; Mayo, Christie, advisor; Raabis, Sarah, advisor; Buttke, Danielle, committee member; Titcomb, Georgia, committee memberNorth American bison (Bison bison) play a critical ecological, cultural, and economic role, yet their long-term conservation and management face challenges from disease threats, anthropologic changes, and translocation-associated risks. This dissertation integrates a One Health approach to assess key aspects of bison health, disease surveillance, and biosecurity policy through a multidisciplinary framework. Specifically, this research (1) establishes a stakeholder-driven definition of bison health, (2) evaluates the epidemiology of Bluetongue Virus (BTV) and Epizootic Hemorrhagic Disease Virus (EHDV) in bison, and (3) assesses the diagnostic performance of serological assays for Mycoplasma bovis, a pathogen of increasing concern. To define bison health from a multisectoral perspective, a two-round Delphi survey was conducted with experts from public, tribal, nonprofit, and private sectors. Experts defined bison health as the ability of populations to express natural behaviors, demonstrate resilience to external stressors, and sustain high reproductive output with minimal intervention. Mycoplasma bovis was identified as a high-priority pathogen, with participants highlighting the urgent need for improved diagnostics, biosecurity measures, and cross-sectoral disease management strategies. In response to the research and biosecurity gaps in bison health identified in the Delphi manuscript, as well as the expanding geographical range of Orbiviruses in the United States, we conducted the first cross-sectional serosurvey of BTV and EHDV in North American bison. This study analyzed samples from 287 animals across nine herds in seven U.S. states. Competitive ELISA assays revealed a seroprevalence of 56.5% for BTV and 57.5% for EHDV, with logistic regression identifying age as a significant predictor of seropositivity (p < 0.01). PCR-based detection of circulating BTV serotypes (6, 11, 13, 17) was noted, indicating exposure to endemic serotypes. Additionally, a significant decline in viremia with increasing age suggesting age-related immune dynamics. These findings provide foundational data for incorporating bison into vector-borne disease surveillance and highlight the need for further investigation into their role as incidental hosts. Given the increasing impact of M. bovis on bison health along with the economic impacts highlighted in the Delphi manuscript, this dissertation also evaluates the diagnostic performance of a newly designed P48 ELISA compared to a commercially available ELISA for M. bovis detection in bison. This chapter assesses sensitivity, specificity, and cross-reactivity, identifying key limitations of current assays and providing recommendations for improving serological surveillance in bison populations. Findings from this study emphasize the need for species-specific diagnostic validation to enhance disease monitoring and outbreak prevention. By integrating Delphi consensus-building, epidemiological surveillance, and diagnostic evaluation, this dissertation provides critical insights into bison disease ecology, biosecurity needs, and translocation risks. The findings support evidence-based policies for disease mitigation and contribute to the sustainable management of bison populations under a One Health framework.