Digital Commons Network^™

Investigating The Ability Of Foxo1 To Maintain Stem Cells, Stella Aime Rios

Theses and Dissertations

Forkhead box O (Foxo) transcription factors are key regulators of stem cell identity and tumor aggressiveness. Prior work from our group and others demonstrates that Foxo factors maintain stem-like states across diverse biological systems; however, the mechanisms by which Foxo1 suppresses differentiation remain poorly defined.

Using C2C12 myoblasts as a model, we investigated whether Foxo1 preserves stem-like programs through regulation of the nuclear pore protein Nup210. RNA interference was used to generate Foxo1 knockdown cells, followed by qRT-PCR, RNA-sequencing, and fluorescence microscopy. Transcriptomic analysis revealed widespread gene expression changes involving metabolic, mitochondrial, and transcriptional pathways. Notably, Nup210 expression was significantly …

Morphological Evolution And Sediment Budget Of A Flood-Tidal Delta On The Rio Grande Delta Plain: Bahia Grande, Texas, Usa, Aleen Pertuz Paz

Theses and Dissertations

The Isabel Delta is a recently formed flood-tidal delta within the restored Bahia Grande system on the Rio Grande Delta Plain, Texas, USA, where renewed tidal connectivity has created conditions for rapid sediment buildup and landform evolution. This study quantified morphological changes from 2008 to 2025 using satellite imagery. It assessed sediment retention by comparing the effective sediment discharge required to reproduce observed delta growth with field-based estimates of sediment supply derived from channel hydrodynamics, cross-sectional area, and suspended sediment concentration. The delta expanded steadily throughout the study period, with increases in bar, channel, and total surface area, and an …

Parasites Of Meaning: When Interpretation Becomes Infection, Kimberly Medrano

Theses and Dissertations

This thesis examines the impulse to seek moral certainty in morally ambiguous first-person confessional narratives and argues that such certainty is unnecessary. When confronted with narrators whose moral positions remain unclear, readers often project their own moral frameworks onto the text to place the narrator within specific moral binaries. This impulse reveals the reader’s discomfort with ambiguity. This study analyzes the confessional narration, No Longer Human by Osamu Dazai. The thesis will explore how its confessional narrator resists moral clarification. Drawing on Friedrich Nietzsche's critique of moral binaries and J. Hillis Miller’s concept of the “Critic as Host,” this thesis …

Identification Of Peptides For A Muc13 Cancer Vaccine, Abigail Olivia Gomez

Theses and Dissertations

Mucin 13 (MUC13) is a transmembrane glycoprotein that is frequently overexpressed in epithelial cancers. Its extracellular domains and cytoplasmic signaling potential contribute to disrupted cell adhesion, increased invasion, and cancer-promoting pathways, making MUC13 a promising target for immunotherapy. This project used an in-silico approach to identify MUC13-derived peptides predicted to bind HLA class I molecules and support CD8+ T cell-mediated immune responses. Bioinformatics tools were used to screen candidate epitopes for HLA binding affinity, antigenicity, toxicity, IFN-γ-inducing potential, and population coverage, allowing rational prioritization of peptide candidates for experimentation. Selected peptides were evaluated in THP-1-derived macrophages using RT-PCR, Western blotting, …

On The Structure Of The Homotopy Lie Algebra Of Local Rings, Dawson M. Strong

Theses and Dissertations

This thesis investigates the construction and homological properties of the homotopy Lie algebra π(R) of a commutative local ring (R,m,k). Drawing upon the theoretical framework of differential graded (DG) algebras, we first establish the theory of minimal free resolutions and other standard topics in homological algebra. The core of this work details the iterative construction of the acyclic closure R⟨Y⟩ of k over R, which is achieved by the systematic adjunction of exterior and divided power variables to eliminate cycles in homology. We demonstrate that this acyclic closure serves as a minimal free resolution and provides the means to define …

Two Essays On Finance: Co-Opted Directors And Mergers And Acquisitions And The Impact Of Biodiversity Risk On The Cost Of Bank Loans, Fariba Gholami

Theses and Dissertations

This dissertation comprises of two papers. In the first paper, co-opted board members, those appointed after the CEO assumes office, are poor monitors and, contrary to prior assumptions, ineffective advisors. I show that board co-option is associated with suboptimal merger and acquisition (M&A) decisions, adverse deal characteristics, and lower acquirer’s short- and long term returns and operating performance. These results are robust to the use of propensity score matching, entropy balancing, Instrumental variable using 2SLS, and difference-in-differences to address selection bias and endogeneity. Cross-sectional evidence indicates that the negative effects of board co-option are more pronounced when boards are less …

Teaching At The Ai Crossroads: Educators’ Experiences, Ethics, And Practice In Pharmacy Education, Crystal Marie Zuniga

Theses and Dissertations

Artificial intelligence (AI), including emerging generative AI tools, is increasingly influencing healthcare workflows and reshaping expectations for workforce preparation. Pharmacy technician education must respond to these shifts while maintaining academic rigor and prioritizing patient safety, ethical practice, and professional accountability. This qualitative study examined pharmacy educators' perspectives on the integration of AI within the Pharmacy Technician Program at Southern Valley College, with attention to how educators interpret AI’s relevance, risks, and instructional implications in pharmacy education.

Data collection included one focus group and individual semi-structured interviews with four pharmacy educators with diverse professional experiences in pharmacy practice and education. Data …

Sub-Ghz Propagation Along Freight Trains For Wireless Onboard Communications, Dario Hinojosa

Theses and Dissertations

With the increasing length of freight trains, maintaining reliable wireless communication for onboard sensors has become increasingly challenging. Sub-GHz communication bands are a promising solution due to their long-range capability and suitability for rural railway environments. This study analyzes radio wave propagation around freight railcars to evaluate path loss and determine how antenna polarization affects wireless communication performance.

Time-domain full-wave electromagnetic simulations were performed using simplified railcar models and later validated through field testing using a vector signal generator, vector network analyzer (VNA), and spectrum analyzer. Various antenna polarization configurations were evaluated within the Sub-GHz Long Range (LoRa) frequency band …

Teaching Under Restriction: Pre-Service Teachers’ Experiences With Censorship, Johnny Salinas

Theses and Dissertations

This qualitative study examined the perceptions of pre-service teacher candidates at a predominantly minority university in South Texas about educational censorship in K–12 schools. Grounded in critical theory, the research explored how restrictive policies—including book bans and legislation related to race, gender, and identity—affect candidates’ developing professional identities and career aspirations. Data were collected through an anonymous, open-ended questionnaire and analyzed to identify six interconnected themes: autonomy and fear, book bans, policy and legislation, race and identity, subject-specific impacts, and readiness and confidence. Participants described an increasingly tense educational climate marked by heightened scrutiny and ambiguous policy expectations. They voiced …

Teacher Stories In A Place-Based Science Education Program In The Trans-Nueces Region, Brian Craig Gabrysch

Theses and Dissertations

This qualitative study examines the emerging professional narratives of five educators involved in the Integrated Oceans Program at a coastal South Texas school district situated within the Trans-Nueces region. Guided by the central research question—What are the emerging teacher stories from a place-based science program in the Trans-Nueces region, and what do we learn about place-based science education from the narratives?—the study employs narrative inquiry methodology following Riessman (2008) and Bruner (1985) to investigate how educators construct meaning from their practice within a program anchored to the Laguna Madre wetlands ecosystem.

The theoretical framework integrates interpretivism (Benton & Craib, 2010), …

La Panza: Un Acto De Rebeldia Para Los Atravesados Y Los Que Siguen Despues / The Panza: An Act Of Rebellion For The Inbetweeners And Those Who Follow After, Abigail Guadalupe Cantu

Theses and Dissertations

Our ancestors, family members, and ourselves that live in the borderlands have embodied knowledge, and/or an innate intuition that comes from the pit of our soul, particularly from our “panza”; hence, the creation of a panza consciousness as the focus for my thesis. I’m trying to “rediscover” the embodied knowledge that has been taken from us and how we can learn to harness these forms of knowledge into a societal shift ( i.e. how we interact with others, how we see our bodies, how see the creation of knowledge, and how we see the world). Although, Eurocentric ideals sought to …

Accurate Polyp Segmentation With Visual Mamba, Diego Adame

Theses and Dissertations

Medical image segmentation is a fundamental task in computer-aided diagnosis because it enables precise delineation of anatomical structures and pathological regions from clinical images. While convolutional neural networks and Transformer-based models have achieved strong performance on many medical segmentation benchmarks, CNNs struggle to model long-range dependencies and Transformers often incur high computational complexity for high-resolution medical images. Recently, state space models have emerged as an efficient alternative for dense prediction tasks due to their ability to capture long-range dependencies with linear complexity. However, existing Mamba-based segmentation models still rely on pixel-wise raster scanning that disrupts spatial locality and use simple …

A Case Study Of One-To-One Mobile Teaching And Learning Environments Measuring Creativity In A Rural Elementary School In Deep South Texas, David Warren Hernandez

Theses and Dissertations

This qualitative case study examined how creativity is enacted within rural one-to-one mobile teaching and learning environments in Deep South Texas. Grounded in the frameworks of mobile learning affordances (Klopfer et al., 2002), the Technological, Pedagogical, and Content Knowledge (TPACK) framework, and the SAMR model, the study explored how instructional practices, student agency, and contextual conditions influenced creative learning experiences in an elementary school setting. Data were collected from five elementary teachers at a rural South Texas district and included semi-structured interviews, classroom observations, and samples of student-created artifacts. Data analysis followed a systematic process of first-cycle coding, second-cycle axial …

Soil Water Content Beneath Agrivoltaic Installations In A Subtropical Semi-Arid Climate, John Justin Rodriguez

Theses and Dissertations

Agrivoltaics (AV) not only beneficially influences agricultural microclimates in the field, AV systems can generate on-site energy to offset operational costs, diversify income sources, and improve overall resilience, while providing environmental co-benefits such as reduced heat stress on plants and improved resource use efficiency. This thesis evaluated agrivoltaic shading effects on SWC and soil temperature using high-resolution in situ measurements collected over one year in an active vineyard, incorporating row type, soil depth, shading, and time of day. With precipitation as the primary water source, shaded soils exhibited up to 24.53% lower SWC relative to sun-exposed soils, likely due to …

Multivariate Time-Series Forecasting Of 24-Hour Ambulatory Blood Pressure Using Long Short-Term Memory And Temporal Fusion Transformers, Sebastian Alejos Torres

Theses and Dissertations

Time series play a central role in healthcare by enabling continuous patient monitoring and forecasting of physiological and clinical measurements. Traditional models, such as autoregressive integrated moving average (ARIMA), are limited in capturing nonlinear dynamics and irregular sampling. In this study, we develop and evaluate Long Short-Term Memory (LSTM) networks and Temporal Fusion Transformers (TFTs) to forecast 24-hour ambulatory systolic and diastolic blood pressure (SBP and DBP) time series enriched with demographic and clinical features. Mean absolute error (MAE), root mean squared error (RMSE), mean absolute percentage error (MAPE), and R² were used to evaluate predictive accuracy and temporal pattern …

Developing Bilingual Expressive Language Tools For Spanish-Speaking Families In The Rio Grande Valley, Edessa Xcarlet Reyes

Theses and Dissertations

This pilot study examines the development of dialect-sensitive expressive language tools for bilingual children in the Rio Grande Valley. A cross-sectional survey design was used to examine Spanish-speaking caregivers’ confidence, language use, and perceptions of communication support across home, school, and medical settings. The study focuses on culturally and linguistically responsive practices that account for regional Spanish dialectal variation. Findings from this research are intended to inform the development of family-centered expressive language resources and contribute to equitable assessment and intervention practices for bilingual children in speech-language pathology.

The Rio Grande Valley In Text: Exploring The Borderland Within Social Studies Textbooks Via Synoptic Text, Ana Laura Escobar Fuentes

Theses and Dissertations

This qualitative, synoptic text inquiry examines how fourth-grade Texas history social studies textbooks portray Mexicans, Mexican Americans, and the U.S-Mexico border, specifically the Rio Grande Valley (RGV). This research sought to answer the following questions: How do Texas history social studies textbooks portray Mexicans, Mexican Americans, and the US-Mexican border in three South Texas school districts? Within these portrayals, what historical representations/content are included, diminished, or excluded regarding the vast majority of the Mexican or Mexican American community?

Guided by the conceptual framings of Miller and Almaraz and Valerio-Jiménez (consensual history), Garza and his colleagues (critical histories), Anzaldúa’s geography of …

Linking North American Demographic Trends To Mexican Non-Breeding Grounds In A Migratory Warbler, Majuwana Gamage Dulanthi Dileka Kariyawasam

Theses and Dissertations

Migration enables species to exploit seasonal resources despite high energetic costs and mortality risks, making it a key focus for conservation under environmental change. I investigated migratory connectivity in Orange-crowned Warblers using stable hydrogen isotopes (δ²H) from feathers collected at nine non-breeding sites across Mexico. Results indicated generally weak connectivity (MC = 0.18), with most sites hosting individuals from six breeding clusters across Canada and the United States. However, one northwestern breeding group showed strong connectivity, suggesting crosswise migration to eastern Mexico. By integrating these findings with long-term Breeding Bird Survey data, I detected contrasting population trends, with Pacific Coast …

Structure–Property Engineering Of Sn-Based Hybrid Perovskites Via Bulky Organic Cation Incorporation: From 3d To 2d Architectures, Kevin Alejandro

Theses and Dissertations

This thesis investigates tin-based hybrid organic/inorganic perovskites (HOIPs) as a lead-free alternative to silicon solar cells. To manipulate optoelectronic and efficiency of the semiconductors, methylammonium was substituted with bulky propylammonium and tetrabutylammonium cations to induce quasi-2D/3D Ruddlesden-Popper phases. X-Ray Diffraction confirmed 2D layered phases in propylammonium hybrids (5-15%), while tetrabutylammonium hybrids faced steric limits, triggering vacancy ordered perovskite phases at 1% concentration. Optical analysis showed a bandgap narrowing from 1.30 eV to 1.26 eV with increased substitution. Although photovoltaic performance generally declined, the 10% propylammonium hybrid achieved the highest fill factor of ~0.79, indicating superior internal charge transport. This work …

Writing And Witnessing Ourselves Into Being: Testimonios Of A Chicana Educator And Latine Students For Social Justice In A Writing Course At A Hispanic Serving Institution, Amy Montoya

Theses and Dissertations

A qualitative study of first-year writing students at a Hispanic Serving Institution (HSI) sought to understand the extent to which the practice of writing testimonios transformed how students constructed their sense of identity for social justice. Guided by the research question: How does the practice of writing testimonios in a writing course at an HSI shape faculty and student identity for social justice? This qualitative study analyzed the lived experiences of three former Latine female undergraduates and the researcher in a co - participatory testimonio methodology study. Grounded in the conceptual frameworks of decolonization (Mignolo & Walsh, 2018; Paraskeva, 2013) …

Are College Students Thinking Twice About Having Kids? How Political Factors May Affect The Future Birth Rate In The United States, Gloria Flores

Theses and Dissertations

The trend of the birth rate decline is an important phenomenon which has attracted scholarly attention in the United States. Prior research has explored factors such as income, education, and personal preferences. However, there is minimal research on how the political environment affects people’s family planning decisions. That is, in what ways might perceptions of modern politics affect whether people decide to have children? The limited amounts of research in other countries focusing on political efficacy and its effects on people’s decision to have children have found that people are highly sensible about their political environment when it comes to …

Degradation And Metabolic Analysis Of Synthesized Quorum-Sensing Signals By The Model Eukaryote Chlamydomonas Reinhardtii, Adam Josef Bach

Theses and Dissertations

Bacterial organisms can “talk” with one another on a colony-wide scale using a communication system known as quorum-sensing (QS) via chemical signals. These signals are produced at a basal rate throughout the life of the bacteria and are classified as autoinducers, which diffuse across the cell membrane. Once the critical concentration is reached, they begin to diffuse back into the cell and initiate a phenotypic change. As these signals exist outside the membrane of their producer, they are also accessible to other organisms. It has already been noted that some plant species uptake these compounds through their roots and break …

Hdra-Fusion: Hybrid Detection With Routed Architecture For Manipulation-Aware Ai Face Forgery Detection, Omar Ebeid

Theses and Dissertations

With the rapid advancements in artificial intelligence-based image generation and manipulation tools, it is extremely difficult to detect if an image is genuine or artificially crafted. Despite extensive research in this area, existing image detection systems suffer from three major problems: suboptimal cross-dataset generalization due to shortcut learning of dataset-specific patterns, unreliable probability estimates due to domain shift, particularly in cross-manipulation evaluation settings, and an inability to detect images manipulated by multiple types of manipulations within a single detection framework. To address these limitations, we propose HDRA-Fusion (Hybrid Detection with Routed Architecture), a framework built on the conclusion that different …

Hybrid Machine Learning For Zero-Day Malware Detection: An Adaptive Static-Dynamic Analysis Approach, Garrett Farmer

Theses and Dissertations

In an era of swiftly evolving cyber threats, zero-day malware continues to be one of the most challenging classes of attacks to detect and mitigate. Traditional signature-based methods often fail to detect novel malicious code, leaving institutions vulnerable to unknown exploits. This thesis proposes a machine learning (ML)-based framework that is designed to detect unknown malware variants. By combining both static and dynamic techniques, such as file structure exam ination and sandbox-based runtime analysis, this approach aims to successfully capture malicious characteristics. The proposed custom pipeline addresses the computational overhead that is associ ated with deep inspections, outlining a staged …

Beyond Moving Hands: Narratives Around Deaf Education, Sara Simpson

Theses and Dissertations

This qualitative narrative study explored the experiences and perspectives of deaf educators and educational interpreters working in high school settings. Participants shared narratives about their professional experiences, training, and roles in deaf education. By considering their professional histories, backgrounds, and cultural perspectives, this study examined how these experiences shaped participants’ perceptions of the current state of deaf education.

Using a qualitative narrative research design, three participants with experience working in high school deaf education settings were interviewed individually and later participated in a focus group discussion. The interviews and focus group centered on participants’ perspectives regarding key issues in deaf …

Exploring Servingness Through Pedagogy: A Critical Case Study Of An Hispanic Serving Institution, Yemin Sánchez

Theses and Dissertations

This critical ethnographic case study advances current understandings of what it means to teach at an Hispanic Serving Institution (HSI) and how faculty enact servingness within an HSI enrolling high indices of Latin@/Hispanic students. Drawing on decolonial, culturally sustaining and liberatory pedagogical frameworks, this study interrogates how constructs such as Hispanic, Latin@/Latinx, or coloniality shape the pedagogical conditions under which faculty operate. Using pláticas with ten faculty members, this research study demonstrates servingness is not a technique or an institutional designation, instead, it is a fluid and deeply humanizing ecology with five mutually reinforcing dimensions: Servingness as Relational Praxis, Servingness …

Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez

Theses and Dissertations

Pulsed jet propulsion systems produce inherently unsteady forces whose time-resolved characterization is essential for performance assessment, yet the measured load signal conflates aerodynamic forcing with the dynamic response of the measurement balance itself. This thesis develops a load centered framework for the dynamic characterization of a pulsed jet system, treating the measured load fluctuation as the primary physical observable rather than attempting full true-thrust reconstruction. A single-degree-of-freedom balance model identified through ringdown testing provides the structural reference scale, yielding a natural frequency of 8.5 Hz and damping ratio of 18%. Power spectral density, phase-averaging, and synchronous–residual decomposition is applied uniformly …

Exploration Of Extended Chemical Reaction Networks, Ramiro Santos

Theses and Dissertations

Chemical Reaction Networks (CRNs) is a well-established model for analyzing distributed and concurrent systems. A central problem studied across CRNs is the reachability problem, which asks whether a target configuration can be obtained from a given initial configuration through a sequence of valid transitions. Classical CRNs are highly expressive but not Turing-universal; their reachability problem is Ackermann-complete, indicating extremely high computational complexity that nevertheless falls short of full universality.

In this thesis, we study Extended Models of Chemical Reaction Networks in which the dynamics of the system are modified. We analyze these models through two fundamental questions. First, simulation, we …

Vision-Language Guided Quadruped Navigation With Reinforcement Learning Control, Chen Yuan Wang

Theses and Dissertations

Large Language Models and their multimodal variants, Vision-Language Models (VLMs), can interpret natural language instructions and visual context. Reinforcement Learning (RL) methods such as Proximal Policy Optimization (PPO) have been shown to successfully learn stable quadruped locomotion. This work investigates whether a VLM integrated with an RL controller can control a quadruped robot to perform instruction-following navigation to a predefined target using text instructions, egocentric vision, and proprioceptive state.

Most VLM-based robotics work directly target prediction of robot actions from multimodal inputs. This approach often depends on large amounts of expert demonstration data, generated by controllers such as trained RL …

Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad

Theses and Dissertations

The loading conditions experienced by freight railcar bearings vary as a function of vehicle operating conditions. Under static conditions, bearings are primarily subjected to radial loads transmitted through the wheelset. During operation, however, track irregularities, braking events, railcar load imbalances, and curving introduce complex impact, longitudinal, and lateral forces in addition to the normal radial loading. These lateral forces increase friction within the bearing raceways, which could accelerate wear and potentially lead to premature spall initiation and propagation. While prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that vibration signatures can be used to detect …