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Habitat Assessment and Niche Partitioning Between Hippocamelus antisensis and Odocoileus peruvianus in the Central Andes
No full textUnderstanding how habitat generalists and specialists partition ecological niches under environmental change is essential for biodiversity conservation. This study investigates the habitat suitability and potential niche overlap of two Neotropical deer species Hippocamelus antisensis (Taruka), a high-altitude specialist, and Odocoileus peruvianus Peruvian (white-tailed deer), a habitat generalist—across the central Andes. Using Ecological Niche Models (ENMs) built from occurrence records and environmental predictors; we quantified habitat suitability and assessed niche overlap through Principal Component Analysis and Schoener’s D metric. Results show that H. antisensis is highly dependent on elevation and precipitation seasonality, whereas O. peruvianus exhibits broader ecological tolerance, favoring diverse landscapes including human-modified habitats. A moderate degree of niche overlap (D = 0.5) suggests potential competition in overlapping areas, which may be exacerbated by habitat fragmentation. Alarmingly, only 15.2% of high-suitability habitat for H. antisensis lies within protected areas. These findings highlight the vulnerability of specialists in changing environments and underscore the need for targeted conservation strategies that preserve habitat integrity and mitigate competitive displacement by generalist species
Representation of Mental Health in College Newspapers: A Comparative Analysis
No full textMental health has always been a matter of concern across the global population, particularly among young college students. The rising number of mental health issues in college students is due to the limited knowledge, awareness, and exposure to mental health-related discourse. For instance, there is a gap in exploring college students' mental health through the analysis of college newspapers. The current thesis explores the framing of mental health in the online version of student-run newspapers at three American universities in Texas. Additionally, the present thesis compares the similarities and differences in the frames regarding mental health representation, identifies the predominant frame, and analyzes the changes in coverage frequency from 2020 to 2024 among the three newspapers. To accomplish this, a mixed-methods approach, combining thematic analysis and content analysis, was used to analyze 189 news articles collected from the university newspaper website. Three main frames emerged from the thematic analysis: 1. COVID-19 disintegration and growing mental health challenges; 2. Institutional responses, resources, and limitations; 3. Advocacy, awareness, and coping mechanisms. Subsequently, the content analysis revealed that Frame 2 was the most dominant frame, while Frame 3 was more dominant than Frame 1. It was also found that the coverage frequency of mental health and related issues was highest in 2020 and 2021; however, there was a significant decline from 2022 to 2024. The overall findings suggest that college newspapers focus on informing readers about institutional initiatives to provide support for those in need. Furthermore, the media attention to mental health was higher during the COVID crisis. However, the focus on covering mental health in student newspapers decreased as the crisis became less prominent. Therefore, the present thesis highlights the important need for a more sustainable and consistent framing of mental health issues within college newspapers
Investigating the effects of dietary and management modifications on Salmonella enterica population in harvest-ready beef cattle
No full textSalmonella enterica, a foodborne pathogen, poses a significant public health risk, particularly because of multidrug-resistant strains. Cattle are one of the known reservoirs of Salmonella that contaminates beef products. Whereas antibiotic use in cattle contributes to the selection of antibiotic-resistant strains, it is essential to understand other factors that may influence Salmonella dynamics in cattle and their feedlot environment to mitigate and control related public health risks effectively. With this double-blinded, randomized controlled feedlot study, originally designed to evaluate the effects of dietary (high-starch vs. low-starch) and feeding management (erratic vs. regular feeding) changes on animal performance and liver abscess formation, we aimed to investigate Salmonella prevalence and antibiotic susceptibility profiles in cattle and the feedlot during the approximately 222-day-long feeding period and at harvest. Fecal, hide, lymph node, and soil samples were collected from study cattle, resulting in 863 fecal samples, 309 hide swabs, 131 lymph nodes, and 288 composite pen samples. Salmonella was isolated using standard methods involving non-selective and selective media. Among the 536 isolates tested for phenotypic antibiotic susceptibility, two soil-origin isolates recovered during the feeding period were antibiotic-resistant and likely did not remain persistent due to a lack of selective pressure. Overall, treatments did not affect (P > 0.05) Salmonella prevalence in cattle feces, hides, or the feedlot environment. However, the high-starch diet demonstrated potential as a pre-harvest intervention, reducing Salmonella prevalence by 0.20 (95% CIs 0.02–0.43) in cattle lymph nodes, which may help mitigate and control Salmonella risks in beef products
Increasing Aridity and Interannual Precipitation Variability Drives Resilience Declines in Restored Forests Across China
No full textForestation plays a crucial role in the restoration of ecosystem functions and services, while the sustainability of restored forests arouses pervasive concerns, and the resilience dynamics and mechanisms of these forests remain poorly understood. Here, we utilize the lag-1 temporal autocorrelation of satellite-based vegetation data to evaluate long-term resilience trends in stable and restored forests across China from 2001 to 2020, then apply machine-learning algorithms to explore the key drivers behind these trends. Results show that nearly half (45%) of forest ecosystems have experienced resilience declines, whether they are stable forests (44.4%) or restored forests (44.8%). Increased aridity and interannual precipitation variability have a significant impact on the resilience declines in both types of forest ecosystems. Comparatively, non-climate variables exert a larger impact on resilience declines in restored forests than in stable forests. Resilience declines are more prevalent in restored forests with low plant species richness (0.2 m3/m3). Structural equation models reveal that fewer critical factors directly influence the resilience of restored forests compared to stable forests. These findings underscore the importance of integrating these determinants into ecological restoration efforts to ensure forestation sustainability.National Key Research and Development Program of China. Grant Number: 2022YFF1303204
National Natural Science Fund Project. Grant Number: 4227109
Assessment of Climatic Variability on Cotton Production Using Spatial Analysis
No full textCotton is one of the most profitable crops in the US. Due to climate change and increasing extreme weather events such as drought, heatwave, flooding, etc., farmers are losing yield. As the leading state in cotton production, Texas, experiencing limited precipitation and record breaking droughts, is raising concerns for its grim future. A comprehensive study of climatic effects on cotton production is important to capture and understand the underlying interplay of climatic variables. This study investigates the relationship among the variables and identifies existing spatial patterns. Based on 42 years of historical climatic data, this study measures direction and quantifies the changing cotton production. To accommodate non-linear and heterogeneous datasets, a set of spatial analysis tools is adopted and tested for accuracy. This study finds strong dependency of cotton production on temperature and water stress, where precipitation shows a minimal effect. Surprisingly, this study reveals a pattern of increasing production with increasing water stress and an adverse effect of the temperature. It shows the importance of regulated irrigation and opens the scope for further study for adaptive policy making in cotton harvesting
Enhancing Landscape Architecture Construction Learning with Extended Reality (XR): Comparing Interactive Virtual Reality (VR) with Traditional Learning Methods
No full textThe application of extended reality (XR) in design education has grown substantially; however, empirical evidence on its educational benefits remains limited. This two-year study examines the impact of incorporating a virtual reality (VR) learning module into undergraduate landscape architecture (LA) construction courses, focusing on brick masonry instruction. A conventional learning sequence—lecture, sketching, CAD, and 3D modeling—was supplemented with an immersive VR experience developed using Unreal Engine 5 and deployed on Meta Quest devices. In Year 1, we piloted a preliminary version of the module with landscape architecture students (n = 15), and data on implementation feasibility and student perception were collected. In Year 2, we refined the learning module and implemented it with a new cohort (n = 16) using standardized VR evaluation metrics, knowledge retention tests, and self-efficacy surveys. The findings suggest that when sequenced after a theoretical introduction, VR serves as a pedagogical bridge between abstract construction principles and physical implementation. Moreover, the VR module enhanced student engagement and self-efficacy by offering experiential learning with immediate feedback. The findings highlight the need for intentional design, institutional support, and the continued development of tactile, collaborative simulations.The research was partially funded by an internal grant titled ‘Davis College Grand Challenges Competition (FY 2023 Planning Grant)’ at Texas Tech University
How Topher Tophered while Translanguaging between Lengua de Señas Mexicana and American Sign Language: A Critical Autoethnography on Language, Power, and Identity Formation
No full textThis study presents a structured and reflective autoethnographic inquiry into the identity formation of the researcher, Topher Ávila, a Brown Latinx Disabled/Deaf Queer Immigrant who translanguages through multilingual and multimodal means (signed languages: LSM and ASL; written languages: Español and English) while navigating the U.S. education system from pre-K through postsecondary. The central research question guiding this study asked: How have my identity and language—as a multilingual multimodal Disabled/Deaf learner—been shaped in pre-K to postsecondary education system in the U.S.? This question responds to the central research problem: the U.S. education system’s persistent neglect to recognize and/or support sign language translanguaging, which results in the systemic denial of language access for multilingual and multimodal Disabled/Deaf students. Chapter 1 outlines the background, purpose, research question, scope, and significance of the study. Chapter 2 presents the theoretical framework Deaf-LatCrit, and a literature review addressing gaps in translanguaging and educational equity. Chapter 3 outlines the methodology of autoethnography in the form of los testimonios, along with methods of data collection and analysis. Chapter 4 presents two categories of testimonios: artifact-based and critical events-based narratives. Chapter 5 analyzes themes and offers pedagogical recommendations for justice-centered educational transformation. This dissertation calls for multilingual and multimodal approaches in educational policy and practice, with pedagogical possibilities for BIPOC/Latinx Disabled/Deaf learners to thrive in linguistically affirming and inclusive environments
Essays in Financial Economics
No full textThis dissertation comprises three essays at the intersection of financial economics, systemic
risk, and asset pricing under uncertainty. Collectively, they contribute to a deeper
understanding of how markets respond to extreme events—be they endogenous crashes,
geopolitical instability, or environmental disruptions—and how such risks can be forecasted,
measured, and managed.
The first chapter introduces a novel framework for forecasting intraday flash crashes
in the U.S. equity market using a Normal Double Inverse Gaussian (NDIG) model built on
subordinated Lévy processes. By integrating this with robust early-warning signals—structural
break tests, tail-risk metrics, and multivariate anomaly detection—this chapter demonstrates
that flash crashes, often considered sudden and unpredictable, exhibit detectable
precursors up to 30 minutes in advance. The methodology is validated using minute-byminute
S&P 500 data, providing a valuable tool for real-time market surveillance and regulatory
intervention.
The second chapter constructs the Global Geopolitical and Environmental Risk Index
(GGERI), the first unified financial index to jointly quantify geopolitical and climate
policy uncertainty. Drawing from the Caldara–Iacoviello Geopolitical Risk Index and the
Climate Policy Uncertainty Index, this chapter proposes a rigorous aggregation method and
evaluates the resulting index through long-memory volatility modeling, tail-risk estimation,
and systemic spillover analysis. GGERI is shown to be not only theoretically robust but
also practically valuable—its behavior explains market stress episodes more comprehensively
than either of its components alone. Applications include pricing derivatives linked to macro uncertainty and designing macroprudential safeguards.
The final chapter turns to portfolio construction and risk optimization in the context
of emerging markets, using Pakistan-exposed Exchange-Traded Funds (ETFs) as a case
study. This chapter employs both historical and dynamic optimization techniques—including
Markowitz frontiers and time-varying asset allocation under Student’s t-distributed innovations—
to evaluate performance across long-only and long-short strategies. Tail-sensitive
metrics such as the Rachev and STARR ratios are used to assess downside protection. The
findings reveal significant inefficiencies in traditional benchmarks and offer insights into
how investors can better allocate capital in frontier markets under conditions of heightened
global uncertainty.
Together, these essays underscore the importance of anticipating rare events, integrating
macro-financial risk signals, and applying advanced econometric tools to navigate
a world increasingly defined by systemic disruptions. The dissertation not only advances
theoretical models but also proposes actionable solutions for academics, investors, and policymakers
facing the evolving landscape of financial risk
Wills & Trusts
No full textThe article provides a comprehensive review of recent developments in Texas wills and trusts law. The article analyzes significant judicial decisions and legislative changes that impact estate planning, probate procedures, and fiduciary responsibilities. Beyer offers practical insights for attorneys navigating the evolving legal landscape, highlighting key trends and areas of emerging complexity. He also discusses how recent rulings may influence the drafting and administration of wills and trusts in Texas. The article serves as a valuable resource for legal professionals seeking to stay current in this foundational area of law
2023 STAAR Results Highlight Stronger Performance in Model PLC at Work® Elementary and Middle Schools
No full textThis policy brief describes the academic impact of the PLC at Work® process in Texas Model PLC Schools. By comparing student performance in designated schools to matched peers, the study finds that students in PLC schools experience meaningful gains in math and reading achievement—equivalent to two to four months of additional learning. Gains were consistent across grade spans and especially strong for economically disadvantaged students and English learners. The findings support the value of sustained, high-fidelity professional collaboration in improving student outcomes across diverse educational contexts.
This research was supported by funding from Solution Tree. The findings and conclusions presented are those of the author(s) and do not necessarily reflect the views of the funding organization