Digital Commons Network^™

Exploring Non-Conventional Substrates: The Role Of Hibiscus And Whey In Kombucha Fermentation, Benjamin J. Lee

Master's Theses

This study evaluated the impact of hibiscus and whey as alternative fermentation substrates on the physicochemical, phytochemical, and microbial properties of kombucha. A 2 × 2 full factorial design was used to compare four treatments: black tea + water (BW), black tea + whey (BH), hibiscus + water (HW), and hibiscus + whey (HH). The fermentation solvents (water or whey) were heated to 88 °C, infused with 0.6% (w/v) black tea or hibiscus for 10 minutes, sweetened with 10% (w/v) sucrose, cooled to 22 °C, and inoculated with 20% (v/v) kombucha starter culture. Fermentations were carried out at 22 °C …

Empirical Comparisons Of Partial Dimension Reduction Algorithms In High-Dimensional Regression, Nathan Greenfield

Master's Theses

In high-dimensional regression problems, dimension reduction methods are often used to address the challenges of multicollinearity and estimation instability. Partial dimension reduction extends these ideas by applying dimension reduction to a subset of the predictors, while the remaining predictors are modeled without compression. This approach is particularly useful when it is important to retain variability and interpretability in certain predictors.

This thesis investigates the empirical performance of partial dimension reduction algorithms and introduces a novel algorithm, Iterative Partial Residual (IPR). Two algorithms are considered: a baseline algorithm, Marginal Residual (MR), and the proposed IPR method. Their predictive performance is evaluated …

Measurement And Control Of The Oxidation-Reduction Potential And Its Chemical And Sensory Consequences In Wines, William Jordan Wright

Master's Theses

The oxidation-reduction potential (ORP) is a measurement thought to reflect the overall ability of a solution to oxidize or reduce substances within that solution. In wine, there is no absolute agreement as to which substances control or dominate the ORP; however, oxygen, ethanol, iron-tartrate and copper-tartrate complexes, and glutathione are suspected to play key roles, while sulfur dioxide and phenolics may act as buffers. Anecdotally, some varieties of Vitis vinifera are prone to oxidation while others are prone to reduction, though the chemical basis of this remains unclear. The following works aim to further elucidate the influence of specific chemical …

Associations Between Nutrition-Related Chronic Disease And Food Insecurity: Data From The California State University, Elizabeth Ochoa

Master's Theses

Food insecurity is a growing public health concern consistently associated with elevated rates of nutrition-related chronic disease (NRCD) across the general population. Despite young adulthood being a critical window for dietary pattern formation, this relationship remains minimally explored among college students. This thesis examined associations between food insecurity and NRCD diagnosis, including hypertension, diabetes, hyperlipidemia, and cardiovascular disease, among undergraduate students across the California State University (CSU) system. Cross-sectional data were drawn from the Spring 2021 CSU National College Health Assessment, administered across all 23 campuses. After exclusions, the analytical sample comprised 13,762 students. Bivariate analyses assessed relationships between key …

Environmental Impact Of Preventative Fire-Retardant Applications On Soil Water Chemistry, Patrick C. Michelsen

Master's Theses

Between 1992 and 2012, 84% of all documented wildfires were started by humans. These fires often start around high-risk locations such as power lines and roadsides where fuel loads are near these potential human-caused ignition sources. Point source ignition sites that are surrounded by shrubs or grasslands are especially important because fires that occur within these biomes are responsible for far more destruction of property than forest fires. One strategy that is effective at mitigating the spread of fires from ignition sites that are within grassland or shrub biomes are preventative fire-retardant products (PFRPs). These PFRPs differ from traditional fire-retardant …

Estimating Prey Capture Attempts And Activity Costs In Foraging Emperor Penguins (Aptenodytes Forsteri) Using Integrated Biologging Data, Taylor Rose Azizeh

Master's Theses

To forage efficiently in patchy and unpredictable prey landscapes, marine predators must optimize energy intake while minimizing costs. Central place foragers like emperor penguins face greater energetic constraints during demanding periods of high investment like chick-rearing. I used high-resolution tri-axial acceleration, depth, and GPS data from 25 birds from two feeding seasons (2019 and 2022) to quantify prey capture attempts and a proxy for energy expenditure (overall dynamic body acceleration; ODBA) across dive types (epipelagic, mesopelagic, benthic), phases (descent, bottom, ascent), and over time at-sea. While prey capture attempts per minute did not differ when looking across dive types alone, …

Workplace Incivility And Well-Being: A Moderated Mediation Analysis Of Loneliness And Supervisor Support, Marie Rylance

Master's Theses

By building on previous research and addressing calls to examine the growing epidemic of loneliness, this study investigated how workplace incivility affects employee well-being and workplace outcomes, with attention to the roles of loneliness and supervisor support. Guided by the Conservation of Resources theory, workplace incivility was conceptualized as a resource-draining process that fosters stress states such as loneliness. A key contribution of this study was examining the process through which incivility impacts employees, by testing loneliness as a mediating mechanism and supervisor support as a potential moderator. Using data from 178 participants, regression and mediation analyses were conducted, as …

The Effects Of Educational Materials On Knowledge And Attitudes Toward Psilocybin, Lindsey Elise Wade

Master's Theses

Depression is one of the most prevalent and burdensome mental health conditions worldwide, affecting millions and contributing to over 700,000 deaths by suicide annually. Nearly half of patients with major depressive disorder fail to respond adequately to standard antidepressant treatments such as selective serotonin reuptake inhibitors (SSRIs). Psilocybin-assisted therapy (PAT) has emerged as a promising alternative for treatment-resistant depression (TRD), yet public understanding of this therapy remains limited. The present study examined whether a brief psychoeducational intervention could affect knowledge and attitudes toward PAT among members of the general public in the United States. Participants were randomly assigned to read …

A Functional Mri Meta-Analysis Encoding In Alzheimer’S Disease, Joanne Ha

Master's Theses

Alzheimer’s disease (AD) is the most common form of dementia and is characterized by episodic memory impairment. Numerous functional magnetic resonance imaging (fMRI) studies have examined brain activity differences between individuals with AD and age-matched controls during memory encoding. However, small sample sizes and methodological variability across studies have limited the ability to draw meaningful conclusions regarding brain activity underlying encoding impairments. We conducted a meta-analysis to identify consistent patterns of hyperactivity and hypoactivity in AD during episodic memory encoding. Using PubMed to identify studies that met our inclusion criteria, 1,002 studies were screened; ultimately, seven studies were included in …

A Novel Microfluidic Device For Preclinical Testing Of Chemotherapeutics, Kaija Saleh Ogan

Master's Theses

This work demonstrates the feasibility of a novel microfluidic tumor model that reproduces physiologically relevant nutrient gradients and endothelium–tumor interactions, validating its potential as a preclinical test platform. Finite element simulations of glutamine diffusion and fluid dynamics aligned with experimental tracer studies, and co-cultures supported directed endothelial migration toward tumor spheroids, confirming the device’s ability to mimic in vivo–like behavior.

Current preclinical models often fail to capture the complexity of the tumor microenvironment (TME), limiting their predictive value for therapeutic testing. Nutrient availability and angiogenic signaling are critical drivers of tumor progression, yet they are poorly represented in traditional …

Using Noninvasive Calibrated Cuff Plethysmography To Observe The Effects Of Lifestyle Habits On Arterial Compliance, Joshua M. Whitaker

Master's Theses

Cardiovascular disease remains as a leading cause of death for both sexes and across all racial backgrounds. Continuing to research causes, early predictors, and preventative actions are paramount to ensuring that cardiovascular disease starts to decrease in its activity. Endothelial dysfunction is the earliest known predictor of cardiovascular disease, therefore investigating early detection methods of endothelial dysfunction can improve health outcomes. This study revolves around a non-invasive calibrated cuff device that uses the principles of segmental plethysmography and oscilliometry to measure arterial compliance of baseline and induced hyperemic conditions in human subjects to determine how well arteries vasodilate in response …

Performance Enhancement For Rufa: Rapid Urban Forest Assessment, Nicholas Tan

Master's Theses

Urban forests are crucial to the livability and resilience of cities, offering critical ecosystem benefits such as air quality enhancement, temperature regulation, and biodiversity. Managing said urban forests is essential to ensure their sustainability and adaptability to rapidly changing environmental and climate conditions. The Rapid Urban Forest Assessment (RUFA) tool was developed to address the need for a standardized approach to evaluating and comparing urban and community forestry programs. By analyzing and aggregating tree-specific data across California, such as canopy cover, tree counts, and diversity scores, RUFA assigns a comprehensive urban forestry score for each city. This score allows for …

Flower Color Variation And Its Maintenance: Experimental Ecology Of Serpentine-Adapted Leptosiphon Parviflorus Benth. (Polemoniaceae), Magdalene S. Lo

Master's Theses

Environmental heterogeneity can impose fluctuating selection pressures on species across space and time. If variations of a trait provide fitness benefits in certain environmental conditions but not others, these fitness tradeoffs under fluctuating selection could be a means of maintaining intraspecific variation. A common type of intraspecific variation is the production of anthocyanins, pigments responsible for red, pink, and blue colors in plants and that can also provide protection from abiotic stressors, such as water limitation and heavy metals. Leptosiphon parviflorus Benth. (Polemoniaceae, variable linanthus) is an annual wildflower whose individuals produce either pink or white flowers, and both flower …

Accelerating Relationship Discovery In Chronic Lower Back Pain Through Knowledge Graph And Ontology Enhanced Large Language Models, Damon Lin

Master's Theses

Chronic lower back pain (cLBP) is a widespread public health burden linked to anxiety, depression, and opioid addiction. Interventions aimed at treating cLBP have shown minimal improvements in pain outcomes, leading researchers to reexamine our understanding of cLBP through constructing a causal model. However, constructing causal models through Randomized Controlled Trials are often unfeasible, and relying on domain expertise requires extensive and time-consuming research, posing a serious bottleneck for designing effective treatments. To accelerate this process, we apply Knowledge Graphs, Ontologies, and Large Language Models (LLMs) to aid researchers in determining possible causal relationships. First, we demonstrate how LLMs can …

An Analysis Of Neuroidal Memory Formation Within D. Melanogaster, Jerry Chang

Master's Theses

The Neuroidal model poses a neurobiologically plausible theory for modeling the brain. This symbolic network has been shown to capture realistic memorization behaviors using the JOIN algorithm. The model has also been recently improved by incorporating Watts-Strogatz small-worlds within its base structure. From the efforts of neuroscience researchers, we have access to the Drosophila melanogaster (D. melanogaster) fruit fly’s connectome, which has been found to also contain small-worlds in this thesis. By synthesizing the Ocellar Ganglion (OCG) region of Drosophila, we compare a digitized version of a real-world brain with an instance of the Neuroidal model. In this thesis, we …

Reverse Design Of Solid Rocket Grain Geometry, Yechan Kang

Master's Theses

The reverse design of solid rocket motors remains a challenging process due to the nonlinear relationship between the grain geometry and the internal ballistics. The reverse design process involves obtaining an optimal grain geometry given a target performance curve set by mission requirements, which is the inverse problem of the forward design. The purpose of this study is to assess the validity and implementation of neural network and simulated annealing algorithms to perform the reverse design process. A modified phase field model of the eikonal equation is derived to simulate the evolution of combustion surfaces over time, enabling burn back …

Generalized Detection Of Animal Behavior Using Accelerometers, Alexander J. Arrieta

Master's Theses

Animal mounted sensors are becoming increasingly used to passively monitor both domestic and wild animals. Advances in lightweight accelerometer and GPS technology have allowed many animals to be fitted with high accuracy sensors for extended periods of time. This leads to new opportunities to study animal behavior without direct observation. However, interpreting the raw data is difficult due to the high volume and missing context of the information. Machine learning techniques excel at extracting information from raw data streams and are excellent candidates for processing the sensor data. However, due to large variance in how different animals execute the same …

Abiotic Stress Impacts On Macrophomina Root Rot And Nano-Encapsulated Citrus Oils To Control Fruit And Foliar Pathogens Of Strawberry, Marina J. Gutierrez

Master's Theses

Disease remains one of the major constraints to the productivity and economic success of the California strawberry industry. The most important soilborne pathogen is Macrophomina phaseolina, causing Macrophomina root rot (MRR). The most economically significant airborne pathogens include Botrytis cinerea, causing Botrytis fruit rot (BFR), and Podosphaera aphanis, causing powdery mildew (PM).

Disease severity of MRR is highly dependent on environmental factors. Therefore, understanding which abiotic stressors contribute most to disease development is crucial for effective management. A two-year field experiment at Cal Poly, SLO (2024 and 2025) evaluated the effects of drought stress, two elevated chloride …

Hallucination Techniques For Self-Supervised Synthetic Datasets For Mobile Robots, Wyatt D. Colburn

Master's Theses

Classical techniques in autonomous navigation struggle in tightly constrained spaces. Machine learning has been shown to perform better in these difficult environments but most techniques require large amounts of navigation experience for training. Using a new machine learning paradigm learning from hallucination (LfH), training data can be collected in a safe environment and not require supervision. Data is collected in real time while an agent performs a random walk in free space, supervision is not required as there are no obstacles for the robot to run into. After a random walk a post processing pipeline will hallucinate a safety corridor …

Where Is Dance In Education? Perspectives On The State Of Dance In Independent Schools Across The Midwest And How One School Community Fits Into The Larger Picture, Megan O'Toole

Master's Theses

The goal of this study was to examine the current state of dance education in independent K-12 schools in the Midwest region of the United States. The researcher developed four essential questions to guide the study:

Q1 Which schools had dance programming, and which schools did not have dance programming?

Q2 For the schools that had dance programming, what did the dance programs look like?

Q3 What factors influenced a school’s decision to include dance programming?

Q4 What factors influenced a school's decision to exclude dance programming?

A regional study was conducted to understand the trends associated with current dance …

Dancing With Logic: The Impact Of Integrating Dance In Teaching Introductory Computer Science Concepts On Student Understanding And Engagement, April Monk

Master's Theses

The purpose of this study was to investigate the effectiveness of dance-integrated pedagogical methods in enhancing the learning experiences of students in an introductory computer science course. In particular, the research aimed to measure the impact of creative movement on student comprehension, engagement, and perceptions of computer science. To guide this investigation, the study explored three research questions: Does integrating dance into lessons impact students’ comprehension of fundamental computer science concepts? How does dance integration affect student perceptions of both dance and computer science? And what elements of dance contribute to differences in comprehension between dance-integrated and traditional lessons? A …

A Study On Deepsea Fish Detection Using Convolutional Neural Networks, Poojitha Priyadarshini Madari

Master's Theses

This study investigates automated deep-learning methodologies for two primary tasks, firstly fish and its habitat classification and deep-sea fish detection using the DeepFish dataset. A pretrained ResNet-50 model attained a validation accuracy of 82.8% for multi-class habitat classification, demonstrating robust performance in most habitats based on 6,517 images, although exhibiting lower recall for visually similar or underrepresented classes. A binary ResNet-50 classifier achieved 99.8% accuracy in distinguishing fish from. no-fish images using approximately 40,000 images. The YOLOv5s model, trained on 4,505 images containing 15,463 bounding-box annotations, achieved a mean average precision ([email protected]) of 98.2% All models were trained on the …

Seagrass Carbon Standing Stock In The Northern Gulf Of Mexico: The Role Of Seagrass Beds In Mississippi As Potential Blue Carbon Sinks, Devan Hildebrand

Master's Theses

Organic carbon stored in marine ecosystems is known as blue carbon. Seagrass beds have the ability to contribute to global blue carbon standing stocks through the uptake and sequestration of carbon from the water column. Through coastal management and conservation best practices, blue carbon habitats have the potential to help mitigate the effects of climate change. Although widely studied, knowledge gaps exist on the sediment carbon standing stock of seagrasses. I aim to better understand how persistent seagrass meadows surrounding barrier islands in the northcentral Gulf of Mexico contribute to long-term blue carbon standing stocks. Subaqueous sediment cores were collected …

Life History And Distribution Of Two Species Of Cownose Ray, Rhinoptera Bonasus And Rhinoptera Brasiliensis, In Mississippi Coastal Waters, Anna Millender

Master's Theses

Historically, the American Cownose Ray (Rhinoptera bonasus) was considered the only rhinopterid residing in the northern Gulf of Mexico (GOM); however, recent studies have confirmed the presence of the Brazilian Cownose Ray (Rhinoptera brasiliensis) throughout this region. The current study investigated the life history and distribution of both species within Mississippi waters, an area that previously represented a data gap for both species. From April 2016 – July 2025, 193 R. bonasus and 94 R. brasiliensis were analyzed to describe the reproductive biology. Reproductive timing, mating, gestation length, and parturition were similar among species. Although more …

Why The Long Face? The Distribution And Niche Of The Imperiled Narrow-Faced Kangaroo Rat (Dipodomys Venustus), Garrett L. Gimbel

Master's Theses

Distribution models provide a practical use case of connecting ecological niche theory with species’ occurrence and assemblages. By explicitly linking Hutchinson’s “niche space” with geographic space researchers can gain valuable information on a species’ niche characteristics and interactions, thereby informing conservation and management practices. The narrow-faced kangaroo rat (Dipodomys venustus) is a highly understudied kangaroo rat species endemic to the central coast of California and is an ideal species to explore niche theory in distribution modeling. Three subspecies are currently recognized: The Santa Cruz kangaroo rat (D. v. venustus), the elephant-eared kangaroo rat (D. v. …

Isolation Of The 2019 Bonnet Carré Spillway Effects On The Habitat Suitability Of Brown Shrimp (Farfantepenaeus Aztecus) And Blue Crab (Callinectes Sapidus) Using A Modeling Approach, Mallory Dyson

Master's Theses

In 2019, an unprecedented flood year, the Bonnet Carré Spillway (BCS) was opened on two separate occasions (February 27^th to April 11^th, and May 10^th through July 27^th) diverting a volume 6 times the volume of Lake Pontchartrain into the surrounding coastal waters of Louisiana, Mississippi, and Alabama. The goal of this research was to determine the spatio-temporal influence of these freshwater releases on two economically and ecologically important species (Farfantepenaeus aztecus and Callinectes sapidus) with variable responses to salinity and temperature depending on the age class. The Habitat Suitability Index (HSI) …

Per- And Poly-Fluoroalkyl Substances Fate Across California Wastewater Treatment Plants: A Meta-Analysis Of Formation, Distribution, And Persistence, Elizabeth Reineke

Master's Theses

Per- and poly-fluoroalkyl substances (PFAS) are persistent contaminants that move through municipal and industrial wastewater systems with limited attenuation. As a result, they are increasingly detected in drinking water supplies. Despite growing regulatory concern, a systems-level understanding of PFAS behavior across multiple treatment facilities and watershed settings remains incomplete. This study compiled influent, effluent, and biosolids datasets from more than one hundred California wastewater treatment plants to evaluate PFAS occurrence, transformation, and partitioning across diverse treatment configurations. Analytical steps included calculating removal efficiencies, assessing precursor-to-product oxidation, evaluating co-contaminant correlations, and grouping facilities by process design to quantify configuration-specific fate patterns. …

Serum Concentrations Of Inflammatory Markers And Selected Nutrient Metabolites In Holstein And Jersey Cows Across The Transition Period, Avery Orr

Master's Theses

The transition period, spanning the weeks surrounding parturition, requires dairy cows to undergo synchronized metabolic, endocrine, and immunological adjustments that support the onset of lactation but also heighten disease susceptibility. Although individual inflammatory or metabolic biomarkers have been extensively studied, the integrated immunometabolic dynamics that occur across this period and the difference between breeds is not fully understood. The objective of this study was to characterize longitudinal patterns in key nutrient metabolites and inflammatory markers in Holstein and Jersey cows and assess how these systems interact across the transition period.

A total of 63 Holstein and Jersey cows were sampled …

Computational Study On Protein Docking With Vascular Disease Application, Lohitha Reddy Shanigaram

Master's Theses

This thesis investigates how computational methods can help us understand protein docking and vascular diseases by integrating machine learning. The main goal of this research is to develop a system that can predict whether variants in the SOX17 gene are associated to Pulmonary Arterial Hypertension (PAH), a significant vascular condition. To do this, a dataset of 1,063 SOX17 variants was created using publicly available sources such as ClinVar, gnomAD, LOVD, and Ensembl. The study included cleaning and structuring the dataset, encoding genomic data and training a Random Forest classifier to classify variants as positive, negative, or unknown for disease association. …

Impacts Of Halophila Stipulacea Invasion On Organic Matter Dynamics In Thalassia Testudinum Dominated Seagrass Meadows, Puerto Rico, Jonathan D. Herald

Master's Theses

Halophila stipulacea (Forsskål & Niebuhr) is a tropical seagrass native to the Red Sea, Persian Gulf, and Indian Ocean. In 2002, invasive populations of H. stipulacea were identified in the Caribbean Sea where it now forms large meadows, displaces native seagrasses, alters invertebrate and fish communities, and potentially affects organic matter dynamics in invaded meadows. This study investigated differences in organic matter dynamics between meadows of H. stipulacea and native Thalassia testudinum within the Jobos Bay National Estuarine Research Reserve (JBNERR) on the southern coast of Puerto Rico. From March 2023-March 2024, sampling was conducted across four sites to investigate …