Physical Sciences and Mathematics Commons^™

Developing An Object Level Understanding Of Sine And Cosine As Ratios And A Coherent Trigonometry, Jeffrey Peter Nair

Theses and Dissertations

Solving right-triangle problems as well as integrating right-triangle and circular trigonometry into a coherent understanding are documented challenges for students. Prior research has deeply investigated students constructing ratio meanings for sine and cosine using a circle-first approach, which then can be extended to right triangles. Also, past work has separately documented distinct meanings that are useful for sine and cosine, in addition to the ratio meaning, including as lengths in a unit circle and coordinate points. This study took these existing ideas and put them together into one possible developmental progression, based on APOS theory, where students can learn length, …

Temperature And Hydrologic Context Influence Methane Variability In A Low-Salinity Marsh, Zoie Brauser

Dissertations and Theses

Coastal wetlands are biogeochemical hotspots that capture and transform carbon and nutrients. Wetland restoration is increasingly used as a climate mitigation strategy because of wetlands' capacity to sequester large amounts of carbon. However, low-salinity tidal marshes exhibit high variability in methane (CH₄) emissions, which could partially offset carbon sequestration under certain conditions. Understanding the drivers of CH₄ variability is crucial for restoration and conservation work. This project uses an observational research approach to assess the relationships between environmental factors and carbon dioxide (CO₂) and CH₄ soil gas fluxes in a restored low-salinity tidal marsh …

Synthetic Strategies For Bioactive Peptides: From Aggregation Inhibitors To The Total Synthesis Of Tunicyclin C, Stephanie Graciela Garcia Morin

Theses and Dissertations

In Alzheimer's disease (AD), a brain protein called "tau" abnormally clumps and forms neurofibrillary tangles (NFTs), causing damage to brain cells. Ac-PHF6-NH2 is a hexapeptide segment of tau protein that plays a dominant role in tau aggregation and is used as a model to design tau protein aggregation inhibitors. In this research we synthesized four dehydroamino acid (□AA) containing PHF6 analogues with △Abu (derived from L-threonine) and △Val (derived from □-OH-Valine) at position 2 or 3 via dehydrations or azlactone ring-openings as key reactions. We evaluated their proteolytic resistance, ability to inhibit aggregation of PHF6, and impact on the morphology …

Measuring Proteostasis Changes In Apolipoprotein E Mouse Models Using Quantitative And Kinetic Proteomic Methods, Ariel E.A. Denos

Theses and Dissertations

Alzheimer's Disease (AD) is a neurological disorder associated with brain mass loss and cognitive decline. It affects millions of elderly people and is currently uncurable. Since 1906, when the disease was first described, researchers have uncovered many components of AD pathology. However, it is now evident that curing Alzheimer's Disease will require intervention before the pathological onset of amyloid beta plaque deposition, tau neurofibrillary tangles, and associated neuronal loss. Studying AD from the perspective of early intervention requires special attention to small changes that may disrupt the normal processing of cells. Cells undergo a natural cycle of creation and destruction …

Multi-Band Extinction Modeling In Early-Type Galaxies With Circumnuclear Disks, Nonnie Bash

Theses and Dissertations

In this thesis, we present a spatially resolved, multi-band dust-attenuation method for correcting the stellar luminosity models used in dynamical supermassive black hole (BH) mass measurements. If uncorrected, dust extinction effects may dominate over other systematic uncertainties when determining the BH mass ($M_\mathrm{BH}$). We expand on a simple dust-attenuation method that treats the circumnuclear disk as a thin dust layer embedded in the galaxy midplane. Using a Multi-Gaussian Expansion, we create a three-dimensional stellar luminosity model to calculate the fractions of stellar light originating in front of and behind the disk along each line of sight. We infer the pixel-by-pixel …

Set-Valued Conjugate Calculus And Duality In Optimization And Machine Learning Via Generalized Relative Interiors, Gary Lee Sandine

Dissertations and Theses

Convex analysis, optimization, and duality theory are broadly applicable to a multitude of real-world problems. Theoretical frameworks ensuring strong duality and optimality are fundamentally tied to convex separation under qualification conditions frequently involving topological or relative interiors. These can be empty in convex sets that appear naturally in infinite-dimensional models, yet guarantees of optimality and strong duality are often attainable. This dissertation presents frameworks for applying convex separation via generalized relative interiors to develop generalized calculus rules as well as conditions for strong duality and optimality for infinite-dimensional constrained convex optimization problems.

The first major contribution is the introduction of …

Modifying Lta Zeolites For Reversible Hydrogen Sulfide Capture And Elucidating The Structure Of The Incorporated Metal And Sulfur Ions, Adeyemi D. Ojaide

Theses and Dissertations

Hydrogen sulfide (H2S) is a highly toxic and corrosive gas that poses significant environmental and industrial challenges, particularly within the wastewater treatment and oil and gas sectors. H2S leakage is among the deadliest industrial hazards, highlighting the urgent need for the development of highly efficient, non-corrosive adsorbents. This dissertation provides an in-depth examination of the use of metal-zeolites for H2S capture. We carefully investigate the impact of multiple divalent and one monovalent transition metals on LTA zeolites to optimize H2S removal. While Linde Type A (LTA) zeolites offer a robust structural framework for gas separation, a comprehensive understanding of how …

Application And Development Of Continuum Treatments In Photodetachment Of Anions, Pratichhya Adhikari

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation aims to provide deeper insight into understanding the dynamics of the photodetached electrons and the nature of the parent species. The dissertation provides examples of quasi-bound states of the anion embedded in the continuum of states associated with the neutral species, and shows how they manifest in experimental data, deviating from expectations of direct detachment. This dissertation is primarily computational and applies and develops electronic-structure and continuum models, respectively, and a newly implemented physical dipole treatment of the photoelectron to account for these resonances and to interpret experimental photoelectron imaging data. The content of the dissertation is divided …

Understanding The Long-Term Patterns Of Change Of A Tidal Marsh In Mission Bay, San Diego, California, Carrie A. Shuster, Theresa Sinicrope Talley Ph.D., Drew Talley Ph.D., Zhi-Yong Yin Ph.D., Kellie Uyeda Ph.D.

Theses

Coastal marshes are among California’s most productive ecosystems and the most impacted, having been extensively modified by dredging, filling, and urban development. This thesis investigates over a century of change for a marsh in Northern Mission Bay, San Diego, California using ecological and spatial analyses.

Chapter 1 provides an overview of the environmental history and current land use of the Northern Mission Bay marsh, tracing changes from pre-contact Indigenous stewardship through colonial and modern urban development. It also introduces a restoration plant palette derived from historical and contemporary species occurrences, ecological functions, and documented cultural uses. By integrating ethnobotanical knowledge …

A Graphical Approach To Isospectral Unfoldings, Dallin Seyfried

Theses and Dissertations

Isospectral reductions are mathematical techniques used to shrink a matrix, or a graph, into a smaller, dimensionally reduced form while preserving its spectrum. Simple graphs that share isospectral reductions also share quantum walk properties. As such we further develop the inverse process, isospectral unfoldings, to find graphs that share isospectral reductions. We first prove many conditions relating to isospectral reductions and unfoldings. Afterwards, we define two new unfolding processes: general unfolding which unfolds the graph one vertex at a time, and equitable partition unfolding which excels at larger graph unfolding. In particular, through equitable partition unfolding, we discover many graphs …

Enabling Asl Digital Communication Under Poor Internet Access, Swann Thantsin

Student Theses

Video conferencing degrades asymmetrically. When bandwidth falls, a hearing caller loses picture quality and keeps the conversation; a deaf and hard of hearing signer, whose language is carried entirely in the visual modality, loses the conversation. This thesis asks whether signed video reduced to the rates at which commercial platforms fail can be reconstructed at the receiver well enough to keep signing legible. A twostage reduction pipeline crops to the signer and transmits the face and hands at higher fidelity than their surroundings, achieving a reduction of approximately 99%; reconstruction uses a recurrent bottleneck mixer architecture, trained both conventionally and …

Surface-Modified Zinc Oxide Nanostructures For Ammonia Detection, Gowri Shonali N Ms

Theses and Dissertations

The escalating demand for sustainable gas sensors with low-ppm detection has driven research on surface-engineered nanomaterials for portable air-quality and health screening. This thesis focuses on the fabrication of nanostructured ZnO films as chemiresistive sensors for NH3 detection at RT. This study investigates surface modification using GO, rGO, g-C3N4, Ti3C2Tx; (Se, and Te) ink using a drop casting technique over DC-sputtered ZnO films. Surface modification plays a vital role by providing plenty of active sites, enhancing defective oxygen vacancy, facilitating charge transfer, and synergistic interaction between adsorbed oxygen species to enhance the sensing performance at RT. Among them trGO/ZnO hybrid …

Learning, Abstraction, And Creative Search For Interactive Agents, Jonathan Demke

Theses and Dissertations

Artificial intelligence systems are increasingly deployed as autonomous agents that interact directly with complex environments. Ensuring these agents remain reliable, adaptable, and useful presents an ongoing practical challenge. This dissertation studies agent-environment interactions through a progressive lens, examining behavior from foundational training stability and abstraction discovery to adaptation in unpredictable settings and open-ended creative search. The investigation begins by analyzing how hyperparameter settings affect early-stage Deep Q-Network performance, yielding practical guidelines for debugging reinforcement learning implementations. To address the challenge of long-horizon planning, the discovery of temporally extended options is formalized as the Minimum Shortcut Problem, demonstrating how agents can …

Development Of Minimalist Trifunctional Building Blocks For Chemical Biology Probe Synthesis, Luke E. Bohrer

Electronic Theses and Dissertations

The completion of the Human Genome Project in 2003 generated expectations that genomic information would accelerate the discovery of new protein drug targets and FDA-approved therapies. However, many small-molecule drug candidates continue to fail in clinical trials, and much of the human proteome remains undercharacterized in terms of structure, function, and disease relevance. Chemical tools are therefore essential for defining protein function, mapping protein interactions, and identifying disease-associated molecular mechanisms. Among these tools, small-molecule chemical probes provide a powerful strategy for connecting biological activity with target identification, functional analysis, and the development of effective therapies.

This dissertation describes the development …

A Coupled Reaction-Diffusion Model Of Promoting And Suppressing Interactions Among Cancer Hallmarks In Endometrial Cancer, Jeddy Bennett

Theses and Dissertations

Spatial transcriptomics enables the scoring of Cancer Hallmarks at a high resolution across a tissue biopsy, yet current analyses of these data remain largely descriptive, treating each spot as a static, independent observation. This thesis develops a coupled system of advection-diffusion-reaction partial differential equations to model the hallmark landscape as the steady-state solution of an underlying spatial process, and casts the recovery of its physical parameters as a PDE-constrained inverse problem. The framework is implemented in FEniCSx on tissue-specific finite element meshes derived from two endometrial cancer biopsies provided by the Huntsman Cancer Institute, with subdomains, boundary interfaces, and an …

Sand Distribution On Titan And Implications For Sand Transport And Interconnectedness Of Sand Seas, Delaney Rose

Theses and Dissertations

The vast equatorial sand seas of Saturn's moon Titan are of particular interest for understanding surface processes and the budget of organic materials on Titan's surface. Previous studies have described sand dune morphology, transport, collection, and distribution patterns utilizing Cassini Imaging Science Subsystem (ISS), Visual and Infrared Mapping Spectrometer (VIMS), and Synthetic Aperture Radar (SAR) imagery. Studies have also shown evidence both for and against a global interconnected system of sand transport between Titan's major sand seas. This study worked both to create a higher resolution dataset of sand distribution using trimodal thresholding techniques applied to SAR images, as well …

Spatiotemporal Analyses Of The Biological Condition Gradient (Bcg) For Florida’S Coral Reef, Maya Becker

All HCAS Student Capstones, Theses, and Dissertations

A conceptual model known as the Biological Condition Gradient (BCG) was originally constructed for biological assessments and has recently been adopted for use on Florida’s coral reef after repeated anthropogenic stressors have been linked to declines within the state of the reef. Anthropogenic pressures have reduced water quality, exacerbating coral disease and associated mortality disrupting ecosystem services and biological function throughout Florida’s coral reefs (FCR). The intention of the BCG model is to assess biological condition against increasing levels of anthropogenic stress and to identify biological attributes and measurable increments of change from long term monitoring data. Differences in spatial …

Process From Noise: Erosion Threshold Variability And The Morphology Of Gravel-Bed Rivers, Robert Paul Kostynick

Arts & Sciences Graduate Student Theses and Dissertations

Rivers are remarkably consistent as their geometry, width, depth, and slope change systematically downstream in response to differences in fluid discharge and sediment transport throughout a channel. Rivers move both water and sediment through terrains that depend on these downstream geometric adjustments influencing water quality, ecology, infrastructure, channel morphology, and landscape evolution at increasing timescales respectively. Rivers thus influence all aspects of life and define our spatial landscapes that shape boundaries, whether physical, politically, or socially. Nevertheless, a river is dynamic and does not adhere to human-defined boundaries, making it vital that we understand how these features change over time …

Assessing The Impact Dynamics Of Less Lethal Ammunition, Steven Bermejo

Student Theses

Less-lethal ammunition is widely used by law enforcement as an alternative to lethal force during crowd control, on-street confrontations, and other situations requiring force. Although these projectiles are intended to reduce risk of fatal injury, serious injuries and fatalities have been reported, highlighting the need to better understand the factors that influence their impact behavior. This study evaluated the impact dynamics of four types of 12-gauge less-lethal ammunition, including rubber buckshot, single rubber ball, double rubber ball, and Byrna kinetic projectile, using kinetic energy calculations derived from projectile mass and velocity measurements. In addition, Attenuated Total Reflectance Fourier Transform Infrared …

Real Bullets, Plastic Guns: Evaluating The Strength Of 3-D Printed Gun Parts, Maria Latenia Mayol

Student Theses

Privately made firearms (PMFs), often referred to as “ghost guns,” are firearms manufactured or assembled by individuals rather than federally licensed manufacturers. Although the terms are frequently used interchangeably, “ghost gun” more specifically describes an unserialized firearm, whereas PMFs include a broader range of firearms produced through nontraditional manufacturing methods. PMFs may be entirely 3-D printed, assembled from partially completed firearm kits, or constructed by integrating additively manufactured components with commercially manufactured firearm parts. The increasing accessibility of additive manufacturing and widespread dissemination of computer-aided design files have raised concerns about concealment, regulation, and forensic evasion, particularly when factory-manufactured components …

Measuring Cosmic Expansion From Early To Late Times Using Quasars, Galaxies, & Local Supernovae, Rajeev Vaisakh

Physics Theses and Dissertations

This dissertation investigates the evolution of cosmic expansion across a wide redshift ($z$) range by combining measurements from quasars \& galaxies in the distant universe $(z > 0.8)$ with those obtained from stripped-core collapse supernovae observations from the nearby universe $(z < 0.1)$. Using the DESI spectroscopic survey, we analyze large-scale clustering from quasars over $0.8 < z < 2.1$ and emission line galaxies over $0.8 < z < 1.6$, contributing to DESI DR2 BAO and full-shape measurements of cosmic expansion and structure growth. Combined with BBN in flat $\Lambda$CDM, DESI DR2 BAO gives $H_0 = 68.51 \pm 0.58$ km s$^{-1}$ Mpc$^{-1}$, while combinations of DESI BAO with CMB and supernova data show a preference for evolving dark energy, with representative constraints such as $w_0 = -0.752 \pm 0.057$ and $w_a = -0.86^{+0.23}_{-0.20}$ for DESI+CMB+DESY5. Using the ROTSE-III Supernova Survey and the expanding photosphere method (EPM), we measure distances to a sample of six supernovae for which the thermal phase can be clearly identified. This analysis focuses on testing whether reliable EPM distances can be obtained for this population. The resulting distances will eventually be compared with independent estimates from the literature. Establishing consistency with these external measurements represents an important step toward applying this methodology to larger samples, with the eventual goal of using ROTSE supernova distances to provide an independent measurement of the local Hubble constant.

Statistical Methodologies For Count Time Series Analysis And Topological Data Analysis Of Medical Images, Yuhyeong Jang

Statistical Science Theses and Dissertations

This dissertation addresses two distinct topics related to count time series analysis and topological medical image analysis, respectively. The first part of the dissertation comprises an application of a count time series model to analysis of US monthly sex trafficking data and development of a new model for multivariate count data that exhibits serial dependence and overdispersion. By imposing a family of multivariate mixed Poisson distributions on the count random vector, the proposed model can accommodate a broad range of overdispersion as well as positive contemporaneous correlations. For maximum likelihood estimation, a computationally feasible EM-type algorithm is derived based on …

Dynamics Of Microscale Droplets In Respiratory Airways, Md Shamser Ali Javed

Mathematics Theses and Dissertations

We investigate trajectories of microscale evaporating droplets in a stagnation point flow near a wall of a respiratory airway. The configuration is motivated by the problem of advection and deposition of microscale droplets of respiratory fluids in human airways during transmission of infectious diseases such as tuberculosis and COVID-19. Laminar boundary layer equations are solved to describe the air flow while the equations of motion of the droplet include contributions from gravity, aerodynamic drag, and Saffman force. Evaporation is accounted for at both the droplet surface and the wall of the respiratory airway and is shown to delay droplet deposition …

Algebraic And Topological Methods In Computational Neuroscience, Trong-Thuc Trang

Electronic Theses and Dissertations 2020 - Present

Neural data is incredibly rich in combinatorial, topological, and geometrical information, reflecting the intricate shape and connectivity of neural firing patterns. To decipher these structures, neuroscience increasingly relies on advanced mathematical tools to analyze neural activity. Here we study (1) neural codes within the poset P_Code of neural codes and (2) the connectivity of neural population activity within the insular cortex when responding to interoceptive information. In (1), we establish combinatorial constructions for all upward covering relations based on what we call “isolated subsets” with supporting theorems and give a slight modification of the existing downward covering relations. We …

Properties Of Enjoyable Mathematical Contexts From The Student Perspective, Emilie Nadine Hendrickson

Theses and Dissertations

Researchers continue to grapple with how to meaningfully engage students in mathematical content. Many students report disengagement due to perceptions that mathematics is difficult, irrelevant, boring, or anxiety-inducing. This study sought to understand how students interpret and respond to different mathematical problem contexts, with particular attention to the reasons students describe certain problems as enjoyable or unenjoyable. Using semi-structured interviews, this research examined student responses to a variety of mathematical problem types primarily across affective engagement. Students reflected on specific problem contexts and explained which features supported or hindered their enjoyment and engagement. Students described that contexts were enjoyable have …

Extreme Heat And Its Impact On Public Transit Ridership In Nyc, Craig Denton

Theses and Dissertations

This thesis explores the connection between extreme heat events and public transit ridership patterns in New York City, with a particular emphasis on low-income communities. It investigates the intersection of socioeconomic factors and heat-related challenges, analyzing how extreme temperature periods influence overall transit use and why certain routes or neighborhoods experience greater declines in ridership during these events.

Utilizing existing literature, NYC-specific transit and climate datasets, and the broader context of transit equity, this research aims to inform strategies that strengthen climate resilience within urban transportation systems. The study’s findings are intended to support policy development and planning initiatives that …

On A Classification Of Goy/Sabra-Type Shell Models Of Turbulence, Austin Ho

Theses and Dissertations

Since their inception in the 1970s, shell models have proved to be a fruitful testbed for studying theories of turbulence. This thesis considers variations of two classical shell models: the Gledzer–Ohkitani–Yamada (GOY) model and the Sabra model. Up to conjugacy classes, we classify all possible GOY-type and Sabra-type models. We numerically approximate the scaling exponents for the newly identified models and develop their mathematical well-posedness.

Changes In Water Quality And Microbiota Over Two Years In Florida Hard Clam (Mercenaria Mercenaria) Hatcheries, Bonnie Getter

Electronic Theses and Dissertations 2020 - Present

This thesis characterized the water quality and bacterial communities in nine hard clam hatcheries over two production years through weekly or biweekly water quality and chemistry monitoring, monthly bacterial plating in the second year of production, and select 16S microbiome sampling at select hatcheries to address production bottlenecks and support the reliable production of high-quality seed for Florida’s growing hard clam aquaculture industry. Logistic regression models showed that water source was distinguished by pH, salinity, alkalinity, and nitrite, whereas geographic location was distinguished by temperature, salinity, nitrate, and calcium; temperature, dissolved oxygen, salinity, and alkalinity distinguished seasons. Vibrio bacteria differed …

Ai And The Music Industry: Its Current Status And A Speculative Projection Of Its Evolutionary Trajectory, Rhett D. Morris, Clayton Rosati, Stefan Fritsch

Honors Projects

Music serves as one of society's biggest cultural outlets, allowing millions to share in what used to be a uniquely human form of expression. The commodification of music has built a huge industry full of companies and platforms that have used technology and property laws to shape music's relationship with the public. This study aims to look into the future to see how AI and its implementation could affect the structure of the music industry. To look into the future, this piece establishes two of the most pressing kinds of AI technology for the music industry and looks to contextualize …

Community Detection In Bipartite Networks Using Bipartite Stochastic Block Models With Node-Level Covariates, Geraldine Elaine Percival

Dissertations

In this age, monumental webs of data demands for perpetual cultivation of ways to untangle these webs of information. One of the many curiosities is how to systematically group entities. When clustering, one avenue to take is ascertaining the interconnectedness between the data points, and gauging their influence to each other. This perspective is programmed to model the relationships between the data presented as a network. Many of the methods being used today are algorithm-based, which may pose limitations in understanding and explaining the uncertainty revolving around the data. Hence, it is proposed to steer towards a model-based approach that …