Digital Commons Network^™

Information Theory Analysis Of Water Vapor Stable Isotopes From The Sail Campaign, Matthew John Rybecky

Earth and Planetary Sciences ETDs

Understanding the processes that control water vapor isotopic composition in mountain environ- ments is essential for interpreting isotope records and predicting water resource responses to cli- mate change. This thesis applies information theory to continuous, high-resolution water vapor stable isotope measurements from the Surface Atmosphere Integrated Field Laboratory (SAIL) campaign in the East River watershed of Colorado’s Upper Gunnison Basin, spanning the winter- to-spring transition of 2022–2023. The analysis employs Shannon entropy, mutual information, transfer entropy, and joint transfer en- tropy (JTE) to quantify how environmental variables, including surface meteorology, radiation, tur- bulent fluxes, and ERA5 reanalysis products, transfer information …

Pebble Accretion: Compositions And Water Origins Of Terrestrial Planets, Susmita Garai

Earth and Planetary Sciences ETDs

Two leading models of planet formation invoke either stochastic collisions among km-sized planetesimals, or pebble accretion of sub-mm-cm solids regulated by gas drag. While collision based models typically require tens to hundreds of millions of years to assemble terrestrial planets, pebble accretion can produce Mars to Jupiter-mass bodies within the lifetime of the protoplanetary disk. Although widely accepted for the rapid growth of giant planet cores, the role of pebble accretion in forming terrestrial planets, including Earth, remains debated. Here, we investigate the consequences of pebble accretion for Earth’s origin. Here, I combine numerical models and laboratory experiments to find …

Gradients Of Abandonment, William Tatman

Geography ETDs

As urban-rural disparities drive depopulation in rural areas worldwide, local strategies emerge as pathways for resilience. Research on Ojika, a Japanese island that has lost 75% of its population since the 1960s, reveals an Abandonment Gradient: a nuanced pattern of disuse adapted to modern polycrises. Extending the concept of "lying fallow" to homes and infrastructure, this thesis focuses on abandonment practices that reflect complex realities of labor, capital, and climate uncertainty. Rather than viewing depopulating communities as passive victims of out-migration, this paper argues they are critical sites for generating crisis response. Communally crafted attitudes toward unused space and more-than-human …

Wildfire Impacts On Fluvial Hydrology From Watershed To National Scales, Paige G. Tunby

Civil Engineering ETDs

Wildfires alter the water quantity and quality in downstream river networks. Fires promote biodiversity, maintain habitat, and provide many ecosystem services in a fire-adapted landscape. However, changes in the natural fire regimes can alter ecosystem function and threaten the water security of impacted downstream communities. The magnitude, timing, and persistence of these impacts are difficult to predict due to the lack of high-resolution datasets with adequate coverage to evaluate spatiotemporal trends after a fire. This dissertation moves us beyond the status quo to evaluate post-fire fluvial responses across scales, from the event-scale impacts after the Hermit’s Peak-Calf Canyon wildfire in …

Examining Conditional Indirect Media Effects Through Normative Perceptions: The Role Of Traditional Family Gender Role Expectations And Stigmatizing Beliefs In Human Papillomavirus Vaccination, Moonsun Choi

Communication ETDs

This dissertation examines how indirect media effects operate through normative perceptions within a gendered and stigmatized health context of HPV vaccination. Specifically, this study investigates how these normative mediation processes are conditioned by traditional family gender role expectations at the norm formation stage and stigmatizing beliefs about HPV vaccination at the normative influence stage. A cross-sectional survey was conducted with mothers of children aged 9 – 12 in the United States in June 2025. The key findings show that while gendered perceptions of HPV vaccination persist, the underlying normative mechanism operated in similar ways across gender-referent contexts. Injunctive norms were …

Who Bears The Burden: Tax Incidence And Water Governance In The Middle Rio Grande Conservancy District (Mrgcd) Within Bernalillo County, Michael W. Wilson

Economics ETDs

This study examines how property-value-based assessments within a large western irrigation and flood-control district distribute fiscal burdens across property owners. The empirical analysis is restricted to Bernalillo County within the Middle Rio Grande Conservancy District (MRGCD), using parcel-level administrative data from fiscal year 2025 merged with 2021 irrigation service records and geospatial information. The analysis classifies 34,397 parcels by irrigation status, agricultural valuation enrollment, and primary use to evaluate whether non-irrigating residential and commercial parcels, including renter-occupied properties that lack direct irrigation access, bear a disproportionate share of financial responsibility for a district whose first listed priority under their primary …

Making Meaning Of Gendered Experiences: A Mixed Methods Analysis Among U.S. College Students, Andrea Bancroft

Individual, Family, and Community Education ETDs

Gender inequities rooted in patriarchal norms shape the experiences of college-going emerging adults across many domains, often to the detriment of young women. In this study, we applied a mixed-methods approach to analyzing how college students interpret and make meaning from gendered experiences, and how the meaning making process relates to these emerging adults’ sense of university belonging. Participants provided written narratives of a gendered experience and completed a survey about university belonging. Through our qualitative analyses of the narrative responses, we identified four themes that represent cultural socialization messages that these participants engaged with in their narratives: bioessentialism, expectations …

Fifth- And Sixth-Year High School Persisters: Engagement In The "Finishing Year" A Qualitative Case Study, Rebecca A. Knowles

Teacher Education, Educational Leadership & Policy ETDs

This qualitative study aimed to illuminate the ways in which fifth and sixth-year high school students engaged emotionally, socially, and cognitively as they persisted in their education at a large, comprehensive high school. High school in the United States is traditionally a four-year educational experience. For some students, however, high school extends into a fifth and sixth year. These students have been referred to as super seniors, over-age students, and persisters. Although much research has been done regarding students who drop out of high school, including students who eventually earn an alternative credential, very little research has included those who …

Womanhood On The Veranda: Maternalism And The Expansion Of American Women's Public Life, Abigail J. Swanson

History ETDs

Motherhood and child welfare became central organizing principles for reform during the United States Progressive Era.  From these guiding principles, the government formed the United States Children’s Bureau. It was the country's first governmental agency that focused solely on the welfare of children. Mothers writing to the federal government for motherhood advice was a phenomenon that was completely new to twentieth century mothers. Women took pride in their roles as mothers, particularly when it came to child health matters. To the generation of mothers who came before these early twentieth century letter writers, asking the government for advice on child …

Good Impressions At Work: Exploring Gendered Labor In The Middle Rio Grande, Nm Ad 1100-1500, William F. Marquardt

Anthropology ETDs

This dissertation investigates changes in the gendered division of labor among potters in the Middle Rio Grande Valley, New Mexico (MRG) between A.D. 1100 and 1500. During this time, diverse groups coalesced into some of the largest communities seen in the region until the industrial era. New architectural, technological, religious, and trade practices emerged to help knit these communities together during a dynamic period of change. Pottery making practices changed alongside other developments transforming from manufacture for local consumption to surplus production for exchange. Previous research on gendered divisions of labor have largely portrayed gendered labor as static rather than …

Uv Damage Mapping Reveals Different Impacts Of Xpd Mutations On Global Genomic And Transcription-Coupled Dna Repair, Allyson Hoag

Biomedical Sciences ETDs

Nucleotide Excision Repair (NER) is a fundamental cellular process that removes bulky and helical distorting lesions from the genome through the separate responses of its two subpathways – global genomic (GG-NER) and transcription coupled (TC-NER) DNA repair. The pathways converge with the recruitment of the TFIIH complex, a key step that is mediated by the translocase and helicase activities of  its XPD subunit. Germline mutations in XPD result in the clinical disorders, Xeroderma Pigmentosum (XP) and XP combined with Cockayne Syndrome (XP/CS). The goal of this thesis was to understand if XPD XP and XP/CS mutations differentially impact GG-NER and …

Prenatal Alcohol Exposure Induces Vulnerability To Mild Stress Through Heightened Limbic Glial Activation And Cytokine Release, Justine R. Zimmerly

Biomedical Sciences ETDs

Fetal alcohol spectrum disorder (FASD) results from prenatal alcohol exposure (PAE) and is linked to development of mood disorders, which in turn are driven by dysregulation of the sympathetic nervous system, the neuroendocrine hypothalamic-pituitary-adrenal (HPA) axis, and the central nervous system (CNS) neuroimmune response to stressors. PAE alters brain glial activation and proinflammatory cytokine expression through secondary challenges such as psychological stressors. The goals of the experiments presented in this dissertation were to 1) examine peripheral glucocorticoid receptor function following mild acute stress in adult PAE offspring, 2) characterize a sensitized cytokine stress response in the hippocampus, medial prefrontal cortex, …

Investigating The Corrosion Behavior Of Stainless Steel 316 In Static Lead Lithium Eutectic Under Applied Stressed Conditions, Daniel E. Levario

Nuclear Engineering ETDs

As fusion power moves closer to feasibility, identifying structural materials compatible with breeding blanket environments remains a critical challenge. Lead-lithium eutectic (LLE) is a leading candidate breeder and coolant material due to its low melting point and combined tritium breeding and neutron multiplication capability. However, the corrosive nature of LLE toward structural steels at elevated temperatures must be characterized before these systems can be reliably deployed. This study investigates the corrosion behavior of Type 316 stainless steel in static LLE under applied stress conditions at 550°C using C-ring stress corrosion specimens. Post exposure analysis via optical microscopy, SEM, EDS, and …

Design And Feasibility Study Of An Air-Cooled Reactor Cavity Cooling System For Fluoride-Salt-Cooled High-Temperature Reactors, Alexandra D. Martinez

Nuclear Engineering ETDs

Licensing efforts for Fluoride-Salt-Cooled High-Temperature Reactors (FHRs) are dependent on passive safety systems designed for decay heat removal, yet no prior study has evaluated an air-based Reactor Cavity Cooling System (RCCS) for this role. This thesis addresses that gap by determining whether an air-cooled RCCS can be designed to passively remove post-shutdown decay heat from the Mk 1 FHR. An RCCS configuration was developed and sized using a one-dimensional lumped-parameter design methodology, then evaluated through system-level thermal-hydraulic modeling in RELAP5-3D under a conservative, lower-bound post-shutdown transient. The analysis characterizes the radial heat-transfer pathways from the FHR core to the RCCS …

Boundary Integral Method For A Modified Mullins–Sekerka System, Ly Le

Mathematics & Statistics ETDs

This thesis develops a boundary integral method for a modified Mullins–Sekerka system arising as the sharp-interface limit of a nonreciprocal Cahn–Hilliard model. Nonreciprocal coupling changes the classical Cahn–Hilliard structure by introducing an additional conserved field, leading to coupled elliptic and parabolic dynamics at the interface. Using matched asymptotic expansions, we formally derive the modified Mullins–Sekerka model and then apply the boundary integral method to rewrite it on the moving interface. The elliptic component is represented using the periodic Green’s function for the Laplace equation, while the parabolic component is represented using the periodic heat kernel. This method reduces the bulk …

Nerve Constructions And Mapper, Alexander Bram Fritschi

Mathematics & Statistics ETDs

Mapper is a data visualization tool commonly used in topological data analysis to study large, often high-dimensional datasets. Mapper operates through the selection of a lens function, a clustering algorithm, and a cover. The Mapper graph is constructed using the nerve of the cover after the clustering algorithm is performed; it is therefore useful to study nerves to better understand Mapper. In this thesis, we will utilize the properties of nerves to find the minimal point set that produces a given graph. We will then extend this to Mapper to determine what Mapper graphs may be constructed over a given …

Interpretable Case-Control Inference Through Log-Linear General Location Models, Zacharia Stuart

Mathematics & Statistics ETDs

This dissertation analyzes one of the few publicly available NFL injury datasets to study field type and non-contact lower-limb injuries. Field type is studied jointly with other risk factors to understand how these factors interact to affect injury risk. The data were gathered through a case-control sampling scheme, which limits direct inference on absolute injury probabilities. While not the most common approach for case-control data, this dissertation models the retrospective distribution directly through Log-Linear General Location Models (Log-Linear GLOMs). Through a log-linear structure placed on a log-odds-ratio reparameterization, the model provides directly interpretable marginal and interaction contributions to injury log-odds …

The Uncertainty Principles, Lee Michael Felicetti

Mathematics & Statistics ETDs

The Heisenberg uncertainty principle is a central aspect of quantum mechanics, but also illustrates an essential quality of the Fourier transform. After Heisenberg, a variety of uncertainty inequalities emerged in the fields of physics and mathematics. In this thesis we will analyze the Heisenberg uncertainty principle in both the setting of quantum mechanics and Fourier analysis. We will then look at how the work of Heisenberg has been expanded upon in both physics and mathematics. Particularity, we will see how uncertainty principles can be applied to signal recovery and explore current research in this field.

Multi-Robot Cooperative System For Complex Aerospace Manipulation Tasks: Theory And Application, Longsen Gao

Electrical and Computer Engineering ETDs

Multi-robot systems can extend manipulation capabilities beyond the limits of a single robot, particularly for tasks involving large, flexible, delicate, or free-floating payloads. Reliable cooperative manipulation, however, remains difficult when payload dynamics, contact geometry, compliance properties, deformation-induced forces, and external disturbances are only partially known, and when safety constraints must be enforced during physical interaction. This dissertation develops a two-layer control framework for resilient multi-robot manipulation under uncertainty, with emphasis on space servicing, satellite stabilization, aerial transportation, and cooperative manipulation of free-floating structures.

Enhanced Computational Modeling Of Photoionization And Streamer Formation, Anahita Alibalazadeh

Electrical and Computer Engineering ETDs

Photoionization is a key mechanism governing the formation and propagation of streamer discharges in air by generating electron-ion pairs ahead of the streamer front. Accurate and computationally efficient modeling of this non-local process is essential for reliable plasma simulations. However, the widely used Zheleznyak photoionization model relies on empirical assumptions and requires computationally expensive domain-wide integration.

This dissertation advances photoionization modeling in three ways. First, the classical integral model is enhanced by incorporating experimentally measured vacuum ultraviolet (VUV) emission spectra together with photoabsorption and photoionization cross-section data, enabling direct calculation of the photoionization source term as a function of pressure …

Developing A Dispersion Interferometer For Characterizing Power Flow Plasma Formation And Transport Studies, Nathan R. Hines

Electrical and Computer Engineering ETDs

Sandia's refurbished $Z$-pinch machine experiences persistent current loss in its post-hole convolute and inner magnetically insulated transmission line regions, widely attributed to low-density electrode plasmas whose formation and transport remain poorly constrained by existing diagnostics. This dissertation develops and validates a fiber-coupled, continuous-wave, second-harmonic orthogonally polarized dispersion interferometer for time-resolved measurements of electron areal density in millimeter-scale gaps. The diagnostic employs single-laser second-harmonic generation, non-steering differential phase control, and polarization-based phase retrieval to achieve sub-$10^{15}$~cm$^{-2}$ sensitivity, multi-hundred-megahertz bandwidth, and sub-$200$~$\mu$m effective cross-gap spatial resolution. Performance is benchmarked against a $94$~GHz interferometer on the UNM Helicon-Cathode plasma device and then fielded …

3d Electromagnetic Simulations Of A 1.6 Cell S-Band Photoinjector: Emittance Studies For Electron Microscopy, Trudy Bolin

Electrical and Computer Engineering ETDs

Modern beam-based materials research demands electron sources with increasingly precise time resolution, high brightness, and stability. For example, there are various instruments across the U.S. dedicated to ultrafast electron diffraction (UED), but fewer are dedicated to ultrafast electron microscopy (UEM), which demands beam stability. Modeling femtosecond electron bunches with ultra-low emittance < 50 nm-rad inside a 1.6-cell S-band (2856 MHz) rf photoinjector with full 3D electromagnetic simulations can require high-performance computing (HPC) environments due to the scale disparity between the macroscopic cavity geometry and the femtosecond-scale bunch kinematics. To enable optimization in a desktop computing environment, this work presents a streamlined 3D electromagnetic Particle-in-Cell (PIC) simulation framework optimized for 400-femtosecond bunch regimes. The covariance method was employed to study emittance properties for electron bunch counts ranging from thousands to millions and has successfully resolved highly transient, pure rf phase-space rotations, such as a localized energy-spread minimum occurring at the gun exit iris. To overcome the computational cost of these simulations, a machine-learning-based Bayesian optimization approach was deployed to construct multi-objective Pareto fronts from sparse datasets. Because the simulation software is scalable from desktop to HPC facilities, the framework is ready for experiments at the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory (LBNL).

Real-Time Waveform Synthesis For Rfsoc-Based Quantum Control Systems, Tiamike I. Dudley

Electrical and Computer Engineering ETDs

RFSoCs are gaining adoption in many labs for quantum control systems thanks to their compactness and affordability. Making full use of the many components on an RFSoC evaluation board is a challenging engineering problem that must be solved to realize scalable control systems. In this dissertation, I evaluate the performance of various RFSoC components in the context of quantum information science. I present two custom FPGA engines that accelerate and parallelize arbitrary waveform generation. The first engine can be instantiated many times to power low-speed DACs for ion-shuttling trap electrodes. The second engine synthesizes CPMG-XY8n dynamical decoupling pulse sequences on …

Computationally Tractable Methods For Constrained Optimal Control And Reachability Analysis Of Nonlinear Stochastic Dynamical Systems, Karthik Sivaramakrishnan

Electrical and Computer Engineering ETDs

Autonomous systems operating in uncertain environments require methods that can rigorously quantify safety, predict future behavior, and compute optimal decisions tractably. The unifying challenge is reasoning about uncertainty propagation in constrained dynamical systems. Motivated by autonomous spacecraft inspection, this dissertation develops model-based and data-driven methods for stochastic optimal control and stochastic reachability. First, it studies optimal on-orbit inspection of an uncertain tumbling spacecraft in both single-agent and multi-agent settings, and derives computationally efficient reformulations for exploring trade-offs among sensing, trajectory deviation, and fuel use. Second, it develops a probabilistically safe penalty-based reinforcement learning method that preserves gradient information during training …

Simulations Of Atmospheric Pressure Streamer Discharges: Mechanisms Of Streamer Propagation And Related Physics, Dejan Nikic

Electrical and Computer Engineering ETDs

Gas discharge simulations are performed with particular focus on photoionization process in a positive streamer discharge. The effects of this process are investigated by isolating the change in photoionization mean free path (MFP) and keeping the additional processes constant. Furthermore, comparison are made between various effects of simulation parameters, such as initial conditions, geometry extent, simula- tion particle count etc. All of these simulations are performed using a modern Direct Simulation Monte Carlo Particle-in-Cell (DSMC-PIC) code developed by Sandia Na- tional Laboratories. Large scale simulations including 1 cm and 5 cm electrode gaps are performed under standard atmospheric condition air. …

A Significant Moment In The Colorado River Water Supply Crisis, Jack Schmidt, Anne Castle, John Fleck, Eric Kuhn, Kathryn Sorensen, Katherine Tara

The Traveling Wilburys of the Colorado River

On Sunday, July 12, the surface of Lake Powell was 3524.32 feet above sea level, and the surface of Lake Mead was at 1042.77 ft.7 These elevations equated to 5,505,869 and 7,169,640 acre feet (af), respectively, of live storage in the two reservoirs. The combined total live storage of these reservoirs was 12,675,509 af. The last time the combined total live storage in Lake Powell and Lake Mead was this small was May 23, 1957, during construction of Glen Canyon Dam when the entire amount of 12,668,000 af was stored in Lake Mead.

Dispossession, Environmental Degradation, And Youth Migration Among The Pijao Of Southern Tolima, Neider Devia Merchan

LAII Events

This presentation examines how land dispossession, environmental degradation, and capitalist economic transformations shape youth migration among the Indigenous Pijao people of Southern Tolima, Colombia. Based on semi-structured interviews with Pijao community members from different generations, the talk explores how limited economic opportunities, environmental degradation, and unequal access to land make it increasingly difficult for young people to remain in their territories. At the same time, youth migration affects the transmission of Indigenous knowledge, including oral histories, agricultural practices, language, and community memory. Rather than treating migration as an individual decision, the presentation frames it as part of a broader structural …

Systematic Errors In Judging The Performance Of Others, Michael J. Benson

Psychology ETDs

The well-documented tendency of people to be poor estimators of their relative abilities can be problematic in real life. These errors in are highly asymmetric: the worst performers dramatically overestimate their relative ability, whereas the best performers underestimate theirs (Kruger & Dunning, 1999). There are two possible causes of this misjudgment of relative ability: 1) participants are poor estimators of their own performance, or 2) participants are poor estimators of the comparison group’s performance. Kruger and Dunning (1999) attributed overestimation in the worst performers to the former problem but attributed the underestimation in the best performers to the latter problem. …

Pragmatic Measures In Aided Language Measurement: Aac Clinical Expert Perspectives, Makayla Hydiea Smith

Speech and Hearing Sciences ETDs

Purpose: The augmentative and alternative communication (AAC) discipline currently lacks psychometrically sound aided language measures. This thesis is designed to address one step in developing such measures: to begin to establish the clinical feasibility of three pragmatic measures – communicative intent, independence/co-construction, and imitation/non-imitation. Therefore, the objective of this thesis is to identify the useability of these pragmatic measures.

Method: A qualitative approach in the form of a focus group was used to examine the perceptions of SLP practitioners who are experts in AAC. Rapid qualitative analysis (RQA) was used to identify relevant themes and subthemes.

Results: Overall, the themes …

Veribrief: A Multi-Agent Retrieval-Augmented Generation System For Policy Decision Support, Imane Bahji

Electrical and Computer Engineering ETDs

VeriBrief is a multi-agent retrieval-augmented generation (RAG) system for evidence-grounded economic policy analysis. The system orchestrates a five-stage LangGraph pipeline, retrieval, research, analysis, synthesis, and critique, to produce cited, structured responses while detecting out-of-scope queries. An empirical evaluation on eight questions drawn from official U.S. macroeconomic releases compared VeriBrief against a single-pass RAG baseline. The multi-agent system achieved 100% refusal precision on unanswerable analytical queries versus 0% for the baseline. Unsupported claims fell substantially on answerable factual questions. A context-propagation defect discovered during evaluation was diagnosed and corrected. Limitations include failure of the evidence gate on policy-counterfactual queries and a …