Digital Commons Network^™

Early Visual Predictors Of Progression To Alzheimer’S Disease And Dementia With Lewy Bodies, Abril Baez

Master's Theses

We examined whether specific visual cognitive skills predict progression from Mild Cognitive Impairment (MCI) to Alzheimer’s disease (AD), or dementia with Lewy bodies (DLB). The Benson Complex Figure Task (BCFT) was used to measure visual perception and construction (copy), and visual memory (recall). National Alzheimer Coordination Center longitudinal dataset included participants who remained stable (MCI-stable; n =2630), progressed to AD (MCI-AD; n =798), or progressed to DLB (MCI-DLB; n =59). Baseline BCFT scores were entered into logistic regression models predicting diagnostic outcome. Impaired copy performance was significantly associated with MCI-DLB (B = 0.79, OR = 2.21, BCa CI [0.26, 1.36], …

A Convolutional Neural Network Approach To Breast Cancer Tumor Boundary Detection, James Leah Matlosz

Master's Theses

Breast cancer is the second most common form of cancer and often goes undetected in its initial stages due to its subtle symptoms. As the tumors grow, they become more difficult to surgically remove with clean borders. To minimize the chance of recurrence, a 2D convolutional neural network is developed in this work for delineating tumor boundaries. Specifically, the U-shaped network model is trained, validated, and tested with longitudinal MRI scans of patients diagnosed with breast cancer and undergoing neoadjuvant therapy. For training, image masks were generated as ground truths using signal enhancement ratio segmentation, thresholding, and contour detection. The …

Phylogenetic Comparative Vocal Evolution, Casper W. Buchanan

Master's Theses

Vocal learning is a trait unique to humans, bats, cetaceans, primates, and birds (Jarvis & Nottebohm, 1997; McComb & Semple, 2005; Wilbrecht & Nottebohm, 2003). Although there has been extensive research on vocal learning in songbirds, parrots are an even closer proxy to human learning, as they are social, intelligent, and lifelong learners, with some having repertoires of over 300 sounds (Benedict et al., 2022; Péron et al., 2011; Thomsen et al., 2019; Toft & Wright, 2015). Elevated vocal learning can be attributed to the need for parrots to have strong communication skills through the sharing of information over foraging, …

Towards Automated And Explainable Insider Threat Response In Electronic Health Records: A Role-Aware Machine Learning Framework, Luca Lippi Ornstil

Master's Theses

Healthcare remains a prime target for cyberattacks, with insider misuse and credential compromise posing major risks to Electronic Health Records (EHRs). This thesis introduces a role-aware, explainable anomaly detection and response framework integrated with OpenEMR to address post-authentication threats. Four models—Local Outlier Factor (LOF), Isolation Forest, Autoencoder, and Graph Neural Network (GNN)—detect behavioral deviations across temporal, device, and role-based features, with LOF serving as the primary runtime detector. A configurable policy engine maps anomaly severity to proportional actions, from email alerts to read-only restrictions or account suspension, all reversible and auditable. Evaluation on real EHR logs shows the system’s operational …

Effects Of Temperature And Oxygen Stress On Two Populations Of Olympia Oysters (Ostrea Lurida) From Central California, Buyanzaya Buyanurt

Master's Theses

Olympia oysters (Ostrea lurida) are the only native oyster species to the North American West Coast. A once thriving species, O. lurida populations have dramatically declined over time due to factors such as overharvesting, habitat degradation, and the introduction of invasive predators. Although their populations are still present in estuaries along their habitat range, many of these same stressors persist today, preventing the re-establishment of dense oyster beds and hindering recovery of populations. Among these current day stressors, a major concern are the impacts of climate change, specifically warming water temperatures and the increased frequency of hypoxic events. …

Development Of A Colorectal Cancer Spheroid Model To Improve The Accuracy Of Preclinical Drug Testing, Jillian Trilevsky

Master's Theses

Colorectal cancer is the second leading cause of cancer related deaths worldwide. It currently affects millions of people across the globe and is only expected to increase in impact over the coming years. The most common treatment for metastatic colon cancer is chemotherapy, however, the development of chemotherapeutic drugs is a long and expensive process. A large portion of this development process is spent in preclinical drug testing. However, the models used often lack enough physiological relevance to guarantee the drug’s success in a clinical trial. Due to this gap in testing, researchers seek to develop a more physiologically relevant …

System Characterization Of A Distributed Pressure Sensor Array, Bryan C. Hasselman

Master's Theses

This thesis contributes to ongoing research on bluff body aerodynamics at California Polytechnic State University, San Luis Obispo, by introducing a novel technique for the dynamic characterization of a commercially available digital MEMS pressure sensor. The experimental approach combines a new characterization method with comparisons to traditional techniques, offering a comprehensive evaluation of the sensor’s dynamic performance. Both non-parametric and parametric system identification methods are employed to assess the sensor’s frequency response. This thesis supports further investigations into unsteady aerodynamic forces and provides a cost-effective, hands-on platform for students to gain practical experience with instrumentation, system identification, and frequency-domain analysis.

The Effects Of Grazing On Soil Bacterial Communities In Grassland Of Willitis, California, Puja Shrestha

Master's Theses

Cattle ranching has been a vital part of California's economy and culture since the 1700s. When appropriately applied, cattle grazing can be a powerful tool in ecological restoration as it can mimic natural processes, promote plant diversity, control invasive species, enhance soil health, and create suitable habitats for wildlife. However, poor ranch management can lead to negative impacts such as overgrazing, loss of native species, aquatic contamination and more. This study sought to examine the impacts of grazing management on soil health and nutrient cycling in a restored pasture in northern California. Specifically, this research focused on the effects of …

Dietary Intake And Changes In Body Composition Over The Course Of One Season In Ncaa Division 1 Football Players, Blayke W. Harrison

Master's Theses

Energy intake and macronutrient composition of an athlete’s diet is highly important when considering performance. Additionally, having a favorable body composition (i.e. low levels of fat mass and high levels of lean body mass) is crucial in high-level athletes.The role of nutrition-related support personnel is highly needed by many collegiate athletics programs to achieve these outcomes, yet this resource seems to be undervalued and underused in many settings. The present thesis investigates the effects of providing nutritional support to improve dietary habits and compare changes in specific body composition metrics over the course of one season (pre- and post-season) among …

Building A Novel Question-Answering System Using Retrieval-Augmented Generation For The California Fair Political Practices Commission, Saanvi Dua

Master's Theses

The California Fair Political Practices Commission (FPPC) receives a high volume of inquiries via email from public officials, the general public, and other agencies, which currently requires staff to manually search through informational documents and manuals to provide timely responses. This process is both labor- and time-intensive.

To address this challenge, we design a question-answering (QA) system that drafts responses to emailed questions by retrieving relevant information from the FPPC’s manuals using a retrieval-augmented generation (RAG) framework. Although the current implementation focuses on a single manual, the system is designed to be adaptable to the broader set of FPPC documents. …

Deep Learning Framework For Option Pricing, Kyle Rytand Bistrain

Master's Theses

Accurately pricing American options with market data presents a significant challenge, as foundational models like the Black-Scholes-Merton (BSM) model rely on assumptions that deviate from real-world financial data -- such as log-normal returns, constant volatility, and no dividends -- and fail to account for the key early exercise feature of American options. While parametric models can adjust for these features, the complexity of the resulting models renders them prohibitively difficult to apply in practice for nonspecialists. In response, modern machine learning (ML) techniques provide a set of flexible and powerful alternatives, and recent research has explored the application of ML …

Gene Expression Of Anthocyanin Pigments In The California Native Plant Leptosiphon Parviflorus: Interactions Between Flower Color Morphology And Abiotic Stressors, Weston Gonor

Master's Theses

For plants to survive in harsh conditions imposed by abiotic stressors, they must develop mechanisms of adaptation. One of the common types of adaptation seen in plants is the production of anthocyanin pigments, which have been shown to protect plants from UV radiation, metabolic stress, and drought. In this study, we used the flower color polymorphic species Leptosiphon parviflorus to investigate the role of anthocyanin pigments in protecting plants from abiotic stress. To accomplish this, RNA samples were taken from flower, leaf and root tissue of different flower color morphs of Leptosiphon parviflorus (Polemoniaceae) grown in high magnesium and water …

Alpine Plants And Climate Change: Tracking Community Shifts In Yosemite National, Brooke L. Wallasch

Master's Theses

As climate change progresses, alpine plant communities are predicted to shift upslope as they track temperature over time. Relative to lowland environments, alpine areas are experiencing a faster rate of temperature change due to a phenomenon referred to as elevation-dependent warming. A common approach for tracking plant communities shifts over time, is to conduct resurveys of the same area at several time points, as the Global Observational Research Initiative in Alpine Environments (GLORIA) has done on mountain summits around the world since 2001. In 2011-2013, GLORIA developed a supplemental survey method whereby belt transects were established downslope of summits in …

Using Hydraulic Simulations To Determine The Effects Of Tidal Behavior And Riparian Restoration On Chorro Creek, Jonathan L. Maas

Master's Theses

This thesis examines how tidal backwater effects and riparian restoration influence flooding in the Chorro Creek watershed, a major tributary to the Morro Bay Estuary on California’s Central Coast. Restoration efforts, including levee removal, floodplain reconnection, and revegetation have attempted to improve ecological function and reduce sediment transport. However, recent flood events suggest that these changes may also affect local hydraulics in ways not fully anticipated, particularly under the influence of tides and sea level rise. To analyze these dynamics, a two-dimensional HEC-RAS model was developed using LiDAR terrain, historical imagery, and field data collected from pressure and ultrasonic gauges. …

Experimental Study Of Gas-Dynamic Heating In Hartmann-Sprenger Tubes For Rocket Engine Ignition, Jacob T. Huff

Master's Theses

Ignition systems for chemical rocket engines typically rely on hypergolic propellants or auxiliary electrical hardware to supply the energy required to initiate combustion. The resonance igniter is a simple and robust alternative to these conventional methods, capable of inducing autoignition of non-hypergolic propellants without an external ignition source. At the core of this concept is the Hartmann-Sprenger Tube (HST), a device in which a high-velocity jet of gas impinges on a resonance cavity. This interaction establishes self-sustaining gas oscillations within the cavity that heat the propellants to their autoignition temperature. To facilitate the development of a functional resonance igniter at …

Enhancing Non-Player Character Dialogue In Video Gages: An Evaluation Of Large Language Model-Generated Responses, Lam P. Quach

Master's Theses

As video games increasingly emphasize narrative depth and player immersion, the quality of Non-Player Character (NPC) dialogue has become crucial for creating engaging gaming experiences. This thesis investigates the potential of Large Language Models (LLMs) to generate high-quality NPC dialogue by comprehensively evaluating four state-of-the-art models: Gemma 3 27B, Mistral 7B, QWEN 2.5, and LLAMA 3.1. The study employs a mixed-methods approach, combining human evaluation (N=50 participants) with AI-based assessment across five key benchmarks: coherence, personality expression, engagement, style/tone appropriateness, and overall quality. Participants evaluated 32 dialogue samples (8 per model) generated for a fantasy game context featuring two distinct …

Sparse-Data Orbit Estimation In Low Earth Orbit Using The Markov Chain Monte Carlo Ensemble Gaussian Mixture Filter, Nicholas J. Oden

Master's Theses

The number of space objects (SOs) in low Earth orbit (LEO) continues to increase rapidly, creating challenges for the current ground-based tracking network, which cannot accommodate the projected growth in SOs. Catalog maintenance relies on frequent observations for reliable reacquisition, with Two-Line Element (TLE) sets typically generated daily to mitigate rapid error growth from poor TLE accuracy. This constraint limits the ability to track more objects with existing infrastructure. This work evaluates the Markov Chain Monte Carlo Ensemble Gaussian Mixture Filter (MCMC EnGMF), a nonlinear, non-Gaussian filter well-suited for sparse tracking scenarios where higher post-update accuracy is needed to reduce …

Adjoint Enhanced Panel Methods, Christopher Sheehan

Master's Theses

This thesis describes the development, implementation, and validation of an adjoint-enhanced panel method for two-dimensional airfoil analysis. While conventional panel methods are computationally efficient for flow analysis, they typically rely on relatively computationally expensive finite differencing for gradient calculation in design optimization or sensitivity studies, a limitation addressed by employing the discrete adjoint method. The core of this work involves integrating the discrete adjoint method with a Hess-Smith panel code utilizing Class-Shape Transformation (CST) for airfoil parameterization, which requires the analytical derivation of sensitivities for panel geometry, boundary conditions, and the aerodynamic influence matrix with respect to the CST design …

Enhancing Preparedness: A Genetic Study Of Sar-Cov-2 And Other Microbial Public Health Threats In Wastewater From A College Town, Christian N. Hutchinson

Master's Theses

Problem

The SARS-CoV-2 (COVID-19) pandemic revealed both the systemic vulnerabilities of our healthcare system as well as the importance of timely, localized data for informing public health responses. Traditional testing approaches were essential but often failed to capture the full extent of viral spread, especially in those with mild or asymptomatic conditions that relied on at home testing. This underreporting hindered effective allocation of resources and made developing effective intervention strategies difficult. We also realized the potential for wastewater surveillance to be applied to tracking antimicrobial resistance gene markers. Taken together, this approach should have important implications for improving public …

An Evaluation Of The Relationship Between Beef Cattle Grazing Activity Traits And Conception Methods During The Breeding Season, Jason Dubowsky

Master's Theses

Efficient use of native rangelands and improved reproductive success are primary objectives in beef cattle production. Grazing behavior during the breeding season may be influenced by pasture characteristics, including size and water availability, as well as physiological differences due to reproductive status. This study aimed to evaluate the relationship between grazing activity and conception method in crossbred Angus cows over a 2-year period. The study was conducted during the winter months (December – February) on the Central Coast of California with a mean temperate of 53 degrees Fahrenheit. Cows (n = 76) were blocked by age and then randomly assigned …

Effect Of Seasonal Variability In Methane Emissions And Iron Redox Chemistry At Terrestrial-Aquatic Interfaces, Hermes C. Ruiz

Master's Theses

Methane (CH₄) emissions at terrestrial–aquatic interfaces (TAIs) are significant contributors to the global carbon budget, yet the mechanisms driving methanogenesis remain poorly understood. Limited data exist on how seasonal variations and redox processes influence CH₄ fluxes in these dynamic ecosystems. This study addressed two questions: (1) How are CH₄ fluxes in riverine floodplains and adjacent hillslopes impacted by seasonal variations? (2) What roles do metal redox processes (e.g., iron (Fe)) play in regulating methanogenesis?

In-situ CH₄ flux and solid-phase Fe speciation were quantified in East River, CO, under flooded and drained conditions. Groundwater chemistry, gas flux, and soil physical properties …

Exploring The Moderating Effect Of Boundary Management Strategy In A Remote Work Environment, Brandon M. Vasquez

Master's Theses

Remote work has evolved significantly, especially during the COVID-19 pandemic, and continues to influence employee experiences in both positive and negative ways. Managing the separation between work and personal life is of importance. More specifically, using a boundary management strategy of segmentation may be more effective than an integration strategy because those who separate the two domains of work and family/personal life may be less prone to conflict in their lives. The present study aimed to examine the moderating effect of boundary management strategy on the relationship between remote work and job satisfaction, work-life balance, and well-being. Specifically, it was …

Attention In The Age Of Tiktok: Examining The Cognitive Impact Of Short-Form Video Consumption, Samantha Shannon Sutrisno

Master's Theses

With the rapid growth of popularity among short-form video platforms such as TikTok, media consumption has shifted toward fast-paced and highly engaging formats. This trend raises questions about the potential effects of continuous exposure to brief and repetitive audiovisual stimuli on attention. Research on short-form video’s impact on attention is limited, but prior studies suggest it may influence attention in meaningful ways. This study examined the relationship between short-form video consumption and attention among TikTok users (N = 110) by using the Attention Network Task (ANT), which measures the alerting, orienting, and executive control networks of visual attention. Participants were …

Blenderized Tube Feeding Formulas: Attitudes, Barriers, And Clinical Benefits As Perceived By Registered Dietitians In Pediatric Care, Savannah Smiley Keeler

Master's Theses

Blenderized tube feeding formulas (BTFF) are increasingly recognized as a viable alternative to conventional commercial tube feeding formulas (CTFF) for pediatric patients requiring enteral nutrition. This cross-sectional, exploratory study aimed to assess the experiences, attitudes, and perceived clinical benefits of BTFF use among Registered Dietitian Nutritionists (RDNs) working with gastrostomy-tube-dependent pediatric populations in the United States. A total of 146 RDNs completed a 45-item online survey, which gathered quantitative and qualitative data on BTFF familiarity, feasibility, clinical outcomes, caregiver factors, and institutional barriers. Findings revealed that while BTFF use remains variable across clinical settings, 55.8% of RDNs reported increased utilization …

Evaluation Of The Performance Of The Traveling Wave Differential Element In Protective Relays, Niranjan Kc

Master's Theses

This thesis evaluates the dependability, security, and limitations of the traveling wave differential protection function (TW87) in modern time-domain-based protective relays, using a combination of simulations and hardware testing in a laboratory environment. Fault transients are first generated using the electromagnetic transients program model of a real, 230 kV, 65.7 km long overhead transmission line, which are then played back on real time-domain-based protective relays. Various fault scenarios are chosen to evaluate the impacts of factors such as fault inception angle, distance to fault from line terminals, fault type, fault impedance, and external faults on the relay functions’ performance. Results …

Eating Habits, Eating Behavior Mediators, Body Composition And Physical Fitness Among Rotc Cadets, Kaitlin Renee Hanks

Master's Theses

The physical and mental demands of the military and the requirement to maintain body composition standards make healthful eating essential to military service. Reserve Officer Training Corps (ROTC) cadets are a unique subgroup of the United States military, and the combined demands of their military training and educational pursuits may increase their susceptibility to unhealthy eating patterns. The purpose of this study is to describe the relationship between eating habits, eating behavior mediators, body composition, and physical fitness among ROTC cadets. This study used a cross-sectional design that included an online survey, an inperson body composition assessment, and carotenoid measurements …

Analyzing The Relationship Between Diabetes Duration And Self-Management In Adults With Diabetes, Caroline Noel Stroo

Master's Theses

Diabetes mellitus (DM) is a metabolic disease that affects 14.7% of adults in the United States (Centers for Disease Control and Prevention, 2023). Prevalence of diabetes increases with age, with rates for adults aged 65 and older reaching 29.2% (Centers for Disease Control and Prevention, 2023). Factors such as age, race, obesity, physical activity level, and genetics strongly increase the risk of developing type 2 diabetes (T2DM) (National Institute of Diabetes and Digestive and Kidney Disease, 2016). Diabetes requires complex and comprehensive management to reduce the risk of developing comorbidities (Al-Shabeeb et al., 2021). Factors such as education, familial support, …

The Design Of Coplanar Waveguide Traveling-Wave Kinetic-Impedance Parametric Amplifiers, Jordan Scott Savoie

Master's Theses

Astronomical observations and many physics experiments rely on cryogenic amplifiers for readout. Current sensitivity is limited by the noise figure of high-electronmobility transistor (HEMT) amplifiers, which have proven di!cult to decrease further in recent years. Traveling-wave kinetic-impedance parametric amplifiers (TKIPAs) are an emerging class of amplifiers which have the potential to substantially improve the sensitivity of microwave low-noise amplifiers (LNAs) while also accepting relatively high input powers and amplifying over a wide bandwidth. In this thesis, I present the design, modeling, and testing procedures for coplanar waveguide (CPW) TKIPAs developed by our group at the National Radio Astronomy Observatory. Using …

Lactation Management Training In Graduate Nutrition And Dietetics Programs: A Preliminary Report, Laura Ashton Gillin

Master's Theses

The American Academy of Pediatrics recommends exclusive breastfeeding (BF) for the first six months and continued breastfeeding for at least two years with complementary food. Despite this recommendation, only 24.9% of infants in the United States are exclusively breastfed at six months (Breastfeeding Report Card 2022). Breastfeeding support and lactation management are critical to promoting a successful breastfeeding experience. Specifically, qualified support from a Registered Dietitian Nutritionist (RDN) is recommended, yet graduate students in Nutrition and Dietetics do not receive adequate training regarding breastfeeding intervention. This study aimed to evaluate graduate Nutrition and Dietetic programs to determine the amount of …

Vitamin B12 Deficiency: Confidence, Perspectives, And Practices Among Registered Dietitian Nutritionists, Avery Miller Adams

Master's Theses

Vitamin B12 deficiency is common in the United States, occurring in 20% of adults aged 60 and above (Andres et al., 2004). Veterans are susceptible to B12 deficiency due to tobacco product usage, alcohol consumption, and poor diet quality. Megaloblastic anemia is the second most prevalent vitamin deficiency disorder recorded in military personnel from 1997 to 2015 (Knapik et al., 2021). This exploratory, analytic research aims to assess registered dietitian RDN nutritionists’ (RDN) knowledge, perceptions, and intentions regarding treating vitamin B12 deficiency in a clinical setting. Due to population prevalence differences, responses from VA and non-VA practicing registered dietitian-nutritionists (RDNs) …