UTSA Runner Research Press (Univ. of Texas at San Antonio)
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The Hydrologic Mitigation Effectiveness of Bioretention Basins in an Urban Area Prone to Flash Flooding
No full textThe hydrologic performance and cost-effectiveness of green stormwater infrastructure (GSI) in climates with highly variable precipitation is an important subject in urban stormwater management. We measured the hydrologic effects of two bioretention basins in San Antonio, Texas, a growing city in a region prone to flash flooding. Pre-construction, inflow, and outflow hydrographs of the basins were compared to test whether the basins reduced peak flow magnitude and altered the metrics of flashiness, including rate of flow rise and fall. We determined the construction and annual maintenance cost of one basin and whether precipitation magnitude and antecedent moisture conditions altered hydrologic mitigation effectiveness. The basins reduced flashiness when comparing inflow to outflow and pre-construction to outflow hydrographs, including reducing peak flow magnitudes by >80% on average. Basin performance was not strongly affected by precipitation magnitude or antecedent conditions, though the range of precipitation magnitudes sampled was limited. Construction costs were higher than previously reported projects, but annual maintenance costs were similar and no higher than costs to maintain an equivalent landscaped area. Results indicate that bioretention basins effectively mitigate peak flow and flashiness, even in flash-flood-prone environments, which should benefit downstream ecosystems. The results provide a unique assessment of bioretention basin performance in flash-flood-prone environments and can inform the optimization of cost-effectiveness when implementing GSI at watershed scales in regions with current or future similar precipitation regimes.Integrative BiologyOffice of Sustainabilit
The Unique Effects of Identity Centrality Across Domains on Mental Health in Latinx Sexual Minoritized Emerging Adults
No full textEmerging adults who identify as both ethnic/racial and sexual minoritized individual are exposed to multiple dimensions of discrimination, resulting in an even greater increase in the presence of internalizing symptoms due to experiences of unique co-occurring stigmas. Although research has focused on the impact of identity domains on psychosocial functioning separately, the interplay between various identity domains among ethnic/racial SMEA remains understudied. Addressing this gap, the present study sought to examine the unique associations between personal, cultural (i.e., ethnic/racial and U.S.), and sexual orientation identity centrality with psychosocial functioning (i.e., symptoms of anxiety and depression, psychological well-being), and determine the extent to which these identity domains moderate the relationship between discrimination and psychosocial functioning among a sample of 220 (74.1% female, <i>M</i>age=20.13 years, SD=1.43, 18-24 years old) Latinx SMEA. Results indicated that while both personal identity and ethnic/racial identity centrality were positively associated with psychological well-being, U.S. identity was negatively associated with symptoms of anxiety and depression. Additionally, sexual orientation identity centrality was negatively associated with symptoms of depression. Results also demonstrated that ethnic/racial and sexual orientation-based discrimination was positively associated symptoms of anxiety and depression. Sexual orientation-based discrimination was also negatively associated with psychological well-being, but only when personal identity centrality was high. These findings contribute to the existing intersectional literature on the experiences of Latinx SMEA and provide support for existing theories that note the importance of developing a positive sense of self, particularly within minoritized populations.Psycholog
Genetic Characterization of Juvenile Hormone Degradation Enzyme Mutants
No full textIn insects, pacing of growth and development is regulated by Juvenile hormones (JHs). JHs are potent sesquiterpenoids whose titers must be tightly regulated for normal development. One method of controlling JH titers is by enzymatic synthesis and degradation. Little is known about enzymes in the JH degradation cascade. In this study, we use Drosophila melanogaster to understand the contributions of JH degrading enzymes on classic JH developmental functions. We focused on D. melanogaster's five degradation enzyme genes: two JH esterases (Jhes) and three JH epoxide hydrolases (Jhehs). Our lab had previously generated Jhe double knockout (DKO) and Jheh triple knockout (TKO) Drosophila strains. Phenotypic analysis revealed Jhes are required to restrain body size but not developmental timing; while Jhehs are required for developmental pacing but do not affect size. To determine if these phenotypes were related to JH degradation, we performed genetic epistasis experiments with mutations in the gene encoding a key JH synthesis enzyme, JH acid methyltransferase (Jhamt). We didn't find genetic evidence that the delay of Jheh TKO is linked to JH degradation. However, the larger size of Jhe DKO was rescued by Jhamt mutation indicating JH degradation may be involved with this phenotype. Interestingly, Jheh mutants pupate closer to the food while Jhe DKOs do not, yet Jhamt, Jhe DKO pupae had an intermediate phenotype indicating the possible involvement of JH. Future work should focus on a deeper evaluation of the phenotypes of the Jhamt mutant alone to assess the contribution of JH synthesis to degradation enzyme mutant phenotypes.Molecular Microbiology and Immunolog
Very Large Community College Last-Dollar Promise Program: Impacts on School-to-College Enrollments
No full textThis dissertation examines the impacts of a last-dollar promise program on high school-to-college enrollments at a very large community college (VLCC) district in Texas. The research intends to add to the current literature on the growing popularity of promise programs at two-year community colleges. Specifically, this quantitative study examines first-time-in-college (FTIC) students at high schools with low school-to-college enrollments. It examines the impacts of a promised scholarship opportunity offered by the VLCC at no cost or low cost. The research questions aim to examine if a VLCC's last-dollar promise scholarship in a metropolitan area increases high school-to-college enrollments. In addition, the demographics of the student sample are reviewed to explore the enrollment effects of the last-dollar scholarship by the observable student groups of gender, prior college credit attainment, and ethnicity.
Difference-in-differences (DD) and event-study (ES) methods were used to analyze the effects of the VLCC promise program on high school-to-college enrollments. DD analysis is a widely used methodology to review policy or program effects by sampling a population before and after implementation (Schwerdt & Woessmann, 2020). Event studies complement the DD methodology results by providing further insight into the treatment effect over time (Li & Katri, 2023).
The findings in this study are similar to other studies that examined promise programs at community colleges as explained in Chapter 3. This investigation showed that the promise scholarship offered by the VLCC increased high school-to-college enrollments at each promise-eligible high school by 26 to 28 students, resulting in a 4% to 5% increase in enrollments at the promise-eligible high school for students attending the VLCC. In perspective, the overall impact showed an increase in the total enrollment rate at the VLCC from all promise-eligible high schools, ranging from 15% to 25% (log). The results suggest that the VLCC had a statistically significant impact on high school-to-college enrollments.
The demographics showed significant increases in enrollments for both genders, with females increasing by 15 more students, while males increased by 13 more students enrolled at the VLCC from promise-eligible high schools compared to schools that did not have the promise-scholarship opportunity. There was an overall 14% (log) increase for females, while males showed a 10% (log) increase in students at the VLCC from all promise-eligible high schools. For FTIC students with no prior earned college credits, the results showed an increase of 27 more student enrollment at from eligible high school, representing a 14% (log) increase at the VLCC from all promise-eligible high schools. In contrast, students with prior college credits failed to show changes in enrollment at the VLCC. African American and White student enrollment saw a statistically significant increase of five and eight more student enrollments at schools with promise scholarships, respectively, while Hispanic students showed 14 more students. This translated to African American students showing an increase in overall enrollments at the VLCC by 21% (log), White students by 23%(log), and Hispanics by 9% (log) from promise-eligible high schools. Groups classified as Asian, and Other failed to show any increases in enrollments at promise-eligible high schools.Educational Leadership and Policy Studie
Green Infrastructure and Urban Vacancies: Land Cover and Natural Environment as Predictors of Vacant Land in Austin, Texas
No full textUrban vacancies have been a concern for neighborhood distress and economic decline and have gained more recent attention as potential green infrastructure is known to benefit communities in diverse ways. To investigate this, this study looked into the relationship between land cover, natural environment, and urban vacancies in Austin, Texas. Additionally, we investigated the spatial patterns of green infrastructure and urban vacancies by different income groups to see if low income communities would potentially lack the benefits of green infrastructure. To measure green infrastructure, we used different land covers such as forests and shrublands, as well as natural environments such as tree canopies and vegetation richness, using remote sensing data. Urban vacancy information was retrieved from the USPS vacant addresses and parcel land uses. Through a series of multivariate analyses examining green infrastructure variables one by one, the study results indicate that green infrastructure interacts with residential and business vacancies differently. Additionally, low-income communities lack green infrastructure compared with the rest of the city and are exposed to more urban vacancies in their neighborhoods. Further study is required to understand the dynamics of vacancies in underserved communities and examine how existing vacant land can benefit the communities as ecological resources.Architecture and Plannin
Development of Aptamers for RNase Inactivation in Xtract-Free&trade; Sample Collection and Transport Medium
No full textThere is a significant need to develop new environmentally friendly, extraction-free sample collection mediums that can effectively preserve and protect genetic material for point-of-care and/or self-collection, home-collection, and mail-back testing. Systematic evolution of ligands by exponential enrichment (SELEX) was used to create anti-ribonuclease (RNase) deoxyribonucleic acid (DNA) aptamers against purified RNase A conjugated to paramagnetic carboxylated beads. Following eight rounds of SELEX carried out under various stringency conditions, e.g., selection using Xtract-Free&trade; (XF) specimen collection medium and elevated ambient temperature of 28 &deg;C, a panel of five aptamers was chosen following bioinformatic analysis using next-generation sequencing. The efficacy of aptamer inactivation of RNase was assessed by monitoring ribonucleic acid (RNA) integrity via fluorometric and real-time RT-PCR analysis. Inclusion of aptamers in reaction incubations resulted in an 8800- to 11,200-fold reduction in RNase activity, i.e., digestion of viral RNA compared to control. Thus, anti-RNase aptamers integrated into XF collection medium as well as other commercial reagents and kits have great potential for ensuring quality intact RNA for subsequent genomic analyses.Molecular Microbiology and Immunolog
Friend or Foe? Evaluating Sensor-Based Information Side-Channels and Covert Communication Channels on Modern Wearable Devices
No full textThe proliferation of smart wearables, such as smartwatches, fitness bands, and smart-glasses, has witnessed exponential growth in recent years, providing users with diverse capabilities beyond those of traditional smartphones. These wearable devices are equipped with a wide array of on-board sensors, including motion sensors (such as accelerometers and gyroscopes) and user interaction sensors (e.g., microphones). These sensors convert various physical, biological, and environmental inputs into measurable electrical signals, enabling applications ranging from simple step counting and sleep time monitoring to complex tasks such as continuous activity recognition and on-body authentication. Despite their immense utility, these sensors can be exploited as private information side-channels, inadvertently exposing users to privacy risks if exploited by malicious entities. To tackle these privacy challenges, this dissertation investigates realistic privacy attacks through sensory side-channels on wearables and proposes robust defense and mitigation techniques. Furthermore, it explores secure applications and communication protocols in smart wearables enabled by these sensors. The first research effort of this dissertation explores a potential secure application of motion sensors in wrist-wearables as a handwriting-based user authentication mechanism. It assesses the feasibility and practical deployability of existing authentication techniques that utilize motion sensors on wrist-wearables. The investigation employs data collected from human subjects in realistic and unconstrained settings, highlighting potential challenges that hinder widespread adoption of such authentication methods in mainstream mobile applications and services. The second work in this dissertation explores the possibility of using motion sensors and embedded vibration motors in wrist-wearables to establish a low bandwidth secure side-channel for communication between smartphones and smartwatches, leveraging the human skin as the communication medium. A novel frequency modulation technique is introduced to encode and decode bits as vibration pulses which are then sensed via the motion sensors, demonstrating the feasibility of such communication methods. The third work in this dissertation explores the practicality of handwriting inference using motion sensors in wrist-wearable devices, considering various writing forms such as pencil and paper, finger, whiteboard, and air-writing. This research work examines and empirically evaluates existing handwriting inference frameworks with data collected from realistic and natural handwriting settings. Research results from these investigations demonstrate that due to the highly varying nature of handwriting from person to person, wrist motion sensor-based inference attacks are unlikely to pose a substantial threat to users of current consumer-grade smartwatches and fitness bands. The fourth and final research effort in this dissertation investigates the emerging use of motion sensors in smart-headphones and explores the potential risks of keystroke inference using motion and audio data collected from such upcoming smart wearables. Specifically, a novel keystroke inference framework is developed, which utilizes both acoustic and motion data available from modern headphones to infer user keystrokes on external keyboards. The proposed inference framework is then experimentally evaluated for various keyboard types under different realistic environmental conditions using custom-built and commercial headphone hardware. These results highlight the effectiveness and some limitations of the proposed keystroke inference approach in real-world scenarios, demonstrating the potential privacy risks associated with sensor-equipped consumer electronics such as headphones. By addressing these four research directions, this dissertation aims to enhance the security and privacy of wearable devices, mitigate potential side-channel attacks, and pave the way for future research in secure wearable technology applications and communication protocols.Computer Scienc
Technical Report, No. 108
No full textFrom March to September 2023, the Center for Archaeological Research (CAR) at the University of Texas at San Antonio (UTSA), in response to a request from VIA Metropolitan Transit Authority (VIA-MTA) conducted archaeological monitoring of trench excavation in support of the replacement of existing underground storage tanks and associated utilities at 1720 North Flores Street, San Antonio, Texas. As the project area is located on VIA-MTA property, the project required compliance with the Texas Antiquities Code, and review under the Unified Development Code of the City of San Antonio (Article 6 35-630 to 35-634). The project was conducted under Texas Antiquities Permit No. 30836. David Yelacic, former CAR Director, served as the Principal Investigator and directed the fieldwork until his departure from the CAR in August of 2023. Following his departure, Leonard Kemp assumed the role of Principal Investigator and Sarah Wigley served as the Project Archaeologist. The project area, spanning 0.07 hectares (ha; 0.2 acres), is located east of San Pedro Creek within the current VIA-MTA bus parking lot at the Via Metro Center. Potential resources of concern included the San Pedro Acequia 41BX337), as well as the potential for prehistoric resources associated with the San Pedro Creek. Cultural material dating to the early twentieth century was recovered from one trench. No other artifacts or cultural features were recorded. However, based on the sensitivity of the area, the CAR recommends monitoring of any future ground-disturbing activities that have impacts below the hardscapes within the project area. All artifacts collected and records generated during this project were curated at the CAR curation facility on the UTSA Main Campus under Accession Number 2826
Reactive Polyurethane Grouting for Deep Vadose Zone Contaminant Immobilization
No full textThe presence of contaminants in the deep vadose zone (DVZ) poses a lasting and significant threat to health, and the environment. However, the current methods such as soil flushing or cementitious grouting are challenged when confronted with fine-grained soils. Polyurethane resin exhibits low viscosities in comparison to traditional cement grouts, which facilitates permeation into low-permeability soils. The first essay carried out a series of laboratory pressure grouting and leaching tests to simulate and assess the effectiveness of polyurethane grouting for immobilizing contaminants in the DVZ. Results showed that the cured polyurethane was distributed nearly homogeneously, and grouting reduced the saturated hydraulic conductivity of soil by 37%. The effective diffusivity of iodide, used as a surrogate contaminant, decreased by more than 80% compared to ungrouted soil. The leachability index of the grouted soil was 6.5; meeting the criteria established by the U.S. Nuclear Regulatory Commission (NRC) standard for materials intended for burial with radioisotopes. The second essay used three different grouting materials to immobilize contaminants in DVZ including polyurethane, polyurethan-foam and epoxy. Test results indicate that the relationship between porosity and diffusivity of all grouted samples demonstrates an exponential relationship that aligns with Archie's relation which indicates that grouted samples with lower porosity tend to exhibit lower diffusivity. The hydraulic conductivity results show an approximately linear relationship between hydraulic conductivity and [?^3/(1-?)]^2, aligning with the well-known semi-empirical Kozeny?Carman equation which accounts for the sphericity and diameter of particles. It can be inferred that the grouting in this study can transform DVZ soil to have properties similar to sandstone, as indicated by the similar diffusivity and hydraulic conductivity observed in the grouted soil. The third essay investigates the displacement of contaminants caused by polyurethane grouting and evaluates the effectiveness of soil freezing and soil desiccation in mitigating this displacement. Tests results show that soil desiccation can effectively reduce contaminant displacement from (9.1 ñ 3.5) % to 2.2%. Soil freezing does not effectively decrease contaminant displacement caused by grouting, primarily due to the gas produced during the curing process. The gas generated during polyurethane curing can mobilize the water in the soil, leading to contaminant displacement. As a whole, this study provides a valuable assessment and guidance on the application of polyurethane grouting for contaminants immobilization in the DVZ.Civil and Environmental Engineerin
Greenwashing “Modern Day Slavery” through the Mystique of Prison Farm Labor
No full textIn Charleston, Maine, a town of about 1,500 near the center of the state, there is an orchard with 750 apple trees and a farm where a variety of produce is grown.1 This bucolic setting is on the grounds of the Mountain View Correctional Facility, a 374-bed minimum- and medium-security state prison.2 Incarcerated people tend to the apple trees and vegetables, and every year they cultivate 100,000 pounds of produce that wind up on their prison cafeteria, or chow hall, trays.3 Writing for the New York Times in 2021, Patricia Leigh Brown highlighted how Mountain View's prison food service manager Mark McBrine, who also happened to be “an organic farmer with dirt under his fingernails,” was “making the prison a pioneer in a nascent farm-to-prison table movement.”4 According to multiple media outlets that have reported on Mountain View's food system, it is a model to be emulated—both an antidote to dreary prison food and a cost-saver for the state of Maine.5 [...]Interdisciplinary School for Engagemen