Electronic Theses and Dissertations - UTSA Access Only

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12588/2227

This collection contains electronic UTSA theses and dissertations (ETDs), primarily from 2005 to present. The collection is not comprehensive; search the UTSA Library Catalog for a complete list of UTSA theses and dissertations.

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    Big Take Over: Blackness as Technology in Punk
    (2023-08) Lepovitz, Lyndsey
    Through an analysis of the creative expressions of Black punk music, the question this thesis asks is how can specific forms of liberation be achieved through theorizing Blackness as a technology through modes of Black creativity in predominately white spaces? From the contemporary art pieces of Aaron Douglas, the photographs of Gordon Parks, and many forms of musical production, Black creativity has laid the foundation of what it means to examine and appropriately theorize Blackness as a technology for liberation throughout history and in our contemporary moment; as Katherine McKittrick writes in Dear Science, a love note to Black creativity, “Black method is precise, detailed, coded, long, and forever” (McKittrick 5). To contribute to this conversation, this thesis examines the Black punk music of Bad Brains and The 1865 as a form of Black life writing that specifically embraces using Blackness as a technology with the tools of available media for creative expression. Both Bad Brains and The 1865 demonstrate how Black punk artists have used Blackness in relation to musical media techniques to achieve and multiply what Black humanity can mean. Through a rhetorical analysis of Black Punk music from Bad Brains and The 1865, this thesis demonstrates that when Blackness is theorized and put into use as a technology, there is an ironic capacity to re-humanize Black people and Black communities that have been especially invisiblized.
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    The World You Built: Lessons on Colorism in America
    (2021) Johnson, Julian
    This collection of short stories intends to address the damage inflicted on the black community by colorism. It is a contemporary reflection of my personal experience as a black man in America and a member of a community that had historically been forced to endure the physical and psychological brutality of white supremacy and its racist underpinnings that have challenged even our own assurance of who we are as a people. Each of the three stories combats colorism from different perspectives while also tackling issues such as: white privilege, the fallacy of the white ally, the colonial re-writing of history, and the disruption of black identity.
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    Harnessing the Nascent Proteome in the Plasmodium Liver Stages: New Approaches for Drug Discovery and Parasite Biology.
    (2023) McLellan, James Lyle
    Plasmodium parasite resistance to antimalarial drugs poses a devastating threat to the millions of lives that depend on their efficacy every year. New antimalarial drugs and novel drug targets are in critical need, along with novel assays to accelerate their identification. Given the essentiality of protein synthesis throughout the complex parasite lifecycle, parasite specific translation inhibitors are a highly promising drug class, capable of targeting the disease-causing blood stage of infection, as well as the asymptomatic liver stage, a crucial target for infection prophylaxis. To identify compounds capable of inhibiting parasite translation, we developed an assay to visualize and quantify liver stage translation in the P. berghei-HepG2 infection model. After labeling infected monolayers with o-propargyl puromycin (OPP), a functionalized analog of puromycin permitting subsequent bio-orthogonal addition of a fluorophore to each OPP-terminated nascent polypeptide, we use automated confocal feedback microscopy (ACFM) and batch image segmentation and feature extraction to visualize and quantify the nascent proteome in individual P. berghei parasites and host HepG2 cells simultaneously. After assay validation, we demonstrate specific, concentration dependent liver stage translation inhibition by both parasite-selective and pan-eukaryotic active compounds, and further show that acute pre-treatment and competition modes of the OPP assay can distinguish between direct and indirect translation inhibitors. Striking compound-specific differences in translation inhibition efficacy were found, with the presumed eEF2 inhibitor and clinical candidate, DDD107498, the least effective translation inhibitor tested. To investigate the effects of translation inhibitors during early liver stage schizogony, when we detected peak levels of translational output, we quantified translation and growth inhibition after an acute, 4-hour treatment with 5 translation inhibitors with diverse properties. While we found the initial extent of growth inhibition to be well-correlated with that of translation inhibition, subsequent characterization of parasite translation, growth, and development through to merosome release demonstrated that, surprisingly, a compound's translation inhibition efficacy does not determine the extent of its antiplasmodial effect. We then utilized our assay to characterize the translational output of P. berghei parasites throughout liver stage development and adapted our computational workflow to additionally characterize the subcellular changes in nascent proteome localization we observed. Early schizonts show a marked accumulation of OPP-labeled polypeptides which appeared surrounded by DNA, but not overlapping it, a localization which disappeared later in schizogony concomitant with striking DNA shape changes in the parasite. After implementation of expansion microscopy, we demonstrate that this DNA-dim clearing which is filled with OPP-labeled polypeptides is inside the nucleus, and likely represents the liver stage parasite nucleolus, the site of eukaryotic ribosome biogenesis.
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    Exploring Metal-NHC Complexes for Optoelectronic Applications: Photophysics and Tunable Emission Properties
    (2023) Khan, Md Amran Al Taz
    N-heterocyclic carbene metal complexes have gained considerable attention in the last decade due to their versatility, ease of synthesis, and wide variety of applications including antitumor agents, catalysts, liquid crystalline materials, organometallic polymers, photoactive materials, and organic light-emitting diodes (OLEDs). In this report, we first evaluated the heavy atom effect on a model platinum acetylide complexes featuring N-heterocyclic carbenes as chromophores and evaluated photo physical properties. Two new Pt (II) acetylide complexes with the structure (ICy)2PtR2 (where ICy = 1,3-bis-(cyclohexyl) imidazol-2-ylidene and R = 4-bromo phenylacetylene, IPt-MB; 3,5-dibromo phenylacetylene, IPt-DB;) were synthesized. Both complexes showed the blue emission in both solution and solid-state but differ significantly in terms of lifetime and quantum yield. In comparison to the model complex, IPt-MB showed poor quantum yield and short lifetime decay, whereas IPt-DB showed several-fold higher quantum yield and longer lifetime decay. Next, we investigate a series of Pt(II) acetylide complexes containing N-heterocyclic carbenes with extended conjugation, featuring phenanthrene, pyrene, and fluorene rings, to investigate their corresponding influences on the photophysical properties. In IPt-Phe-PE1 and Au-Phe-PE1, the introduction of phenanthrene chromophore led to the phosphorescence emission observed from both phenylacetylene and phenanthrene triplet states, whereas Au-Phe-PE2 exhibited the phosphorescence emission primarily originating from the PE2 ligand. In contrast, BPt-Fl-PE1 demonstrated a broad phosphorescence emission which is primarily attributed to the charge transfer between phenylacetylene and oligo-fluorene whereas IPt-Pyrene-PE1 exhibited originating from the triplet state of the pyrene chromophore. Throughout these investigations, we observed the significant role of phenylacetylene ligand in inducing phosphorescence in these complexes. Lastly, a nitroxide-mediated polymerization (NMP) reaction was carried out to synthesize a series of random co-polymer by mixing a styrene monomer with a controlled amount of p-(trimethylsilyl ethynyl)styrene. A successful iClick reaction was carried out between Poly-10-Au-PPh3 and PPh3AuN3 to obtain Poly-10-Au2-PPh3.
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    Exploring the Role of Online Pharmacies in Ghana
    (2022) Eab-Aggrey, Naessiamba
    The online pharmacy industry is growing globally, including in the developing world. This study explores the role of online pharmacies in Ghana from the pharmacists’ perspective. In particular, it seeks to understand how pharmacists perceive online pharmacies in Ghana in terms of their larger socio-cultural, policy, and communication dimensions, as well as challenges that they face and foresee in implementing online pharmacies given the resource-poor settings in Ghana. Twenty-one in-depth interviews were conducted and analyzed using the thematic analysis approach. Findings indicate that while online pharmacies were in a nascent stage in Ghana, most pharmacists perceived them as beneficial, offering benefits such as convenience, enhancing access to medication, reducing violence, and gender discrimination against women in the pharmacy profession. Also, online pharmacies were perceived to bridge the gap in care between the hospitals and the community pharmacies and in addressing some of the cultural barriers that have long impeded clients from accessing care. On the other hand, respondents pointed to the lack of adequate infrastructure such as roads, internet connectivity, addressing systems acting as hindrance to Ghana's online pharmacy. Finally, it was noted that involving and communicating with varied stakeholders was key to the success of the online program. This study will help online pharmacy industry players in Ghana understand the industry's general scope, its benefits, pitfalls, challenges, and the way forward.
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    Primate Spermatogonial Stem Cells and Their Niche: A Single-Cell View
    (2023) Singh, Anukriti
    Antineoplastic treatments improve the life expectancy of pediatric cancer patients, but may result in male infertility by ablating spermatogonial stem cells (SSCs). Cryopreservation of testicular tissue obtained before sterilizing treatment is a promising fertility preservation approach, but its clinical application is hindered by the lack of exclusive biomarkers to identify human SSCs and limited size of testicular biopsies. To address this, single-cell RNA-seq was performed on testis cells from immature baboons and macaques and compared to published prepubertal human and mouse testis cell data. The cross-species analysis revealed cell types analogous to human SSCs in baboons and macaques, which differed from mouse SSCs. The correlation of molecular definitions of human spermatogonia with histological definitions of Adark/Apale spermatogonia indicated that all human SSCs are Adark. Furthermore, differences in testicular somatic cell populations between primates and rodents were found, including presence of peripheral glial cells and monocytes in humans. In contrast to mice, primate Sertoli cells segregated into distinct clusters enriched for either ribosomal or mitochondrial gene expression did not include a proliferative subpopulation. Additionally, sets of ligands produced in the somatic cell populations with receptor expression in human SSCs were examined. Cross-species comparison revealed seven ligand-receptor pairs conserved in primates but distinct from mice, including components of activin signaling (INHA-ACVR1B, INHBA-ACVR1B) and signaling to the receptor SDC2 (MMP2-SDC2 FN1-SDC2 and TGFB1-SDC2). Overall, improved identification of prepubertal human SSCs and unique components of their niche may be leveraged for advancing propagation of these cells in vitro for clinical purposes.
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    Exploring the Impact of TNFR2 on Regulatory T Cells and Astrocytes in Experimental Autoimmune Encephalomyelitis (EAE)
    (2023) Montes De Oca Arena, Maria
    Multiple Sclerosis (MS) is a chronic autoimmune disease of the central nervous system which affects over 2 million people worldwide. MS is a heterogenous disease characterized by recurrent, remitting and/or progressive neurological deficits, and clinical manifestations include nerve damage, visual loss, motor and balance impairment, gait disturbance, pain, and others. While several environmental and genetic risk factors have been identified, such as having the human leukocyte antigen DR2b (DRB1*15:01) haplotype, the molecular mechanisms underlying the development and severity of MS remain poorly understood. Tumor necrosis factor (TNF) is a cytokine that exerts its effects through two different surface receptors TNFR1 and TNFR2, and it has been identified as a key player in MS pathogenesis. TNFR2 is thought to have a protective role in experimental autoimmune encephalomyelitis (EAE), a mouse model for MS. However, TNFR2 role in health and disease remains controversial and incompletely understood. Previous data from our lab demonstrated that in the absence of TNFR2, transgenic mice expressing the DR2b allele develop a more severe and progressive form of EAE, exhibiting astrogliosis. Using our transgenic TNFR2 knock out model, we were able to explore TNFR2 influence on gene expression in CD4+ T cells and astrocytes, and to functionally and phenotypically characterize TNFR2 deficient Tregs. Additionally, we were able to optimize a way to identify gene and protein expression within mice brain to further determine the presence and characteristics of reactive astrocytes in our mice models during EAE. Our results provide key insights into the mechanism by which TNFR2 regulates Treg and astrocyte function in the context of EAE.
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    Characterization of FlrB and Its Role in Vibrio Cholerae Motility
    (2023) Himes, Bradley William
    Motility of the Gram-negative bacterium Vibrio cholerae contributes to virulence and environmental persistence. Motility is mediated by a single polar flagellum, composed of five flagellin subunits (FlaABCDE) in the filament, however only FlaA is required for motility. FlrB and FlrC control Class Ⅲ gene expression, which comprise basal body/hook components and include the FlaA flagellin. FlrB is a histidine kinase that phosphorylates FlrC, which in turn activates σ54-dependent transcription at Class III promoters. A V. cholerae strain lacking four (of five) flagellin genes (ΔflaBCDE) is surprisingly non-motile. Selection for spontaneously motile strains in this background resulted in mutations localized to the N-terminus of FlrB, mostly within a Per-Arnt-Sim (PAS) domain. To gain insight into the function of FlrB, ten of these mutations were reconstructed in both wildtype and ΔflaBCDE backgrounds. Motility phenotypes were measured by soft agar motility assays. Western immunoblot analysis of whole cell lysates demonstrated low levels of FlaA in the ΔflaBCDE parent, and FlaA levels increased with the addition of the FlrB mutations. Interestingly, measurement of flaAp-lacZ activity in these strains did not reveal major differences in flaA transcription due to the FlrB mutations. The results indicated that the ΔflaBCDE parent strain was not downregulated for flaA transcription and appears to be upregulated for sugar uptake systems, which is relieved with the introduction of the FlrB mutation. Our results suggest that FlrB may be involved in a novel post-transcriptional regulatory mechanism of FlaA expression which may involve sugar transport.
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    Adaptive and Optimal Protection System Framework for Inverter-based Distribution Networks
    (2023) Gonzalez, Reynaldo Sergio
    Integration of inverter-based resources (IBRs) into the distribution grid is expected to grow substantially more in the coming years. The fault response of an IBR differs vastly from traditional distributed generation (DG) such as synchronous generators. With increased penetration of IBRs in the distribution network, fault currents become bidirectional, and combined with the nonlinear fault response, traditional protection systems face challenges and are more at risk of misoperations. Two approaches which seek to improve the protection schemes under increased IBR penetration include optimal protection coordination (OPC) and adaptive protection. Optimal protection coordination seeks to coordinate relay settings through solving an optimization problem. Adaptive protection changes relay settings based on the prevailing network conditions. Some research has shown the schemes combined to create adaptive and optimal protection systems (AOPS), however the literature is limited and has only been applied to certain types of systems. In this work, a framework for a rolling window AOPS is developed for distribution networks with PV inverters. In addition to the rolling-window AOPS framework applied to PV inverters, three other main novel contributions are added. First, a grid-following PV inverter with nonlinear fault response is modeled and studied under the protection system. Next, improvement is made to the OPC formulation by including the short-time settings as optimization variables. Lastly, a case study on very-short-term load forecasting (VSTLF) is presented, to show the capability of load forecasting to be used as a prediction layer within the AOPS.
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    Gearheads
    (2023) Davis, John M.
    My image and text poetry manuscript takes a documentary approach to examining my sect of gearheads in the south Texas region to understand not only their relationship to their own vehicles but also their self-identification as gearheads. This thesis combines poetry, photography, and automotive mechanics which creates poetry reflecting the gearhead experience. Influenced by past poets such as Muriel Rukeyser, Charles Olson, and William Carlos Williams along with contemporary poets Mark Nowak, Amy England, and Jena Osman, my poetry represents my niche group of gearheads.
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    Power Quality and Power Sharing Controls of AC Micro Grid Systems
    (2023) Akdogan, Mehmet Emin
    The connection of the nonlinear/unbalanced loads and single-phase Microgrids (MG) to three-phase MGs or power grids brings challenges to the MGs operation and causes power quality problems. Nonlinear loads introduce voltage and current harmonics and the connection of single-phase MGs and loads to three-phase MGs creates unbalanced voltage at the point of common coupling (PCC) of the MGs and poor power-sharing among MGs. Furthermore, the interaction of three-phase grid-connected inverter-based resources (IBR) to the weak grid introduces voltage and current harmonics at the PCC and leads to system instability. This dissertation presents a hierarchical control scheme for voltage-controlled photovoltaic (PV) inverters with unbalanced and nonlinear loads in MG. With the proposed controller, the voltage distortion at the PCC decreased from6.38 percent to 1.91 percent after compensation, and the unbalanced and harmonic load are shared proportionally among the distributed generations (DG) units. The work was further expanded by proposing a multi-function control scheme and a modified droop control using energy storage system (ESS) to improve the three-phase PCC voltage quality in Multi-microgrids(MMG). Using this scheme, the voltage unbalance factor (VUF) at the PCC is decreased from 4.3 percent to 0.03 percent, while the three-phase PCC unbalanced power is reduced significantly and reactive power is shared proportionally between different rated MGs. Dissertation then tackles the unbalanced MGs problem in distorted weak grids by proposing a PCC voltage feed-forward control method using selective virtual impedance loops (SVIL) based on multiple dual second-order generalized integrators (MDSOGI). In conclusion, this dissertation focus on improving power quality and sharing in islanded and grid-connected MMGs and investigating the system stability with the proposed methods under abnormal conditions. The effectiveness of the proposed methods are verified using Matlab/Simulink, Opal-RT real-time simulation and experimentally using control hardware-in-the-loop.
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    Assessment of Alpha-amino-beta-carboxymuconate-εpsilon-semialdehyde Decarboxylase (ACMSD) Inhibitors
    (2022) Udokwu, Chinedum
    The biodegradation of tryptophan in the kynurenine pathway provides quinolinic acid (QUIN), the precursor for the de novo synthesis of NAD+. This occurs through, α-amino-β-carboxymuconate-ε-semialdehyde (ACMS) which, nonenzymatically decays to form QUIN. ACMSD catalyzes the breakdown of ACMSD to 2-AMS. By inhibiting the α‑amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD), more ACMS cyclizes to form QUIN which increases NAD+ levels. In this study, diflunisal derivatives were used to assess the inhibition of ACMSD. Some of these derivatives were shown to have stronger inhibitions than diflunisal. The crystal structure of ACMSD in complex with the inhibition compounds showed similar binding modes with diflunisal but different second ring positioning. In this study, two diflunisal derivatives showed half-maximal inhibitory concentration (IC50) values lower than KURA-ACMSD 17 (KA17), a previous diflunisal derivative with an IC50 values of 1.32 ± 0.07 μM. The two compounds, PA-62 and PA-67 had IC50 values of 1.29 ± 0.17 μM and 0.66 ± 0.11 μM against the human ACMSD respectively. This was the first sub micromolar concentration from the diflunisal derivatives. This shows that the diflunisal derivatives can be improved upon to create a more potent inhibitor. The crystal structures of ACMSD in complex of with the diflunisal inhibitors were determined through X-ray crystallography using a bacterial version of the enzyme that had been previously demonstrated to share a similar active site architecture with the human ACMSD. This provided a foundation for understanding the inhibitory mechanism at the molecular level.
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    Latina Principals and the Development of a Mestiza Professional Identity
    (2022) Silva, Teresa Ann
    Minimal research exists about the unique lived experiences of the Latina principal and the personal experiences that have informed her professional identity formation. This qualitative study aimed to explore the lived experiences of Latina principals in South Texas and the personal experiences that have influenced their professional identity formation. Additionally, the study aimed to contribute to the limited body of research related to the development of their professional identity using testimonio to center the voices of Latina principals. Investigating testimonios of Latina principals provides insight into their personal attributes and the environmental conditions that motivate and retain female leaders of color.  The research questions and methodology were grounded in the theoretical framework of Chicana Feminist Epistemology. Testimonios were collected through pláticas as the data collection tool. The data analysis drew three primary themes related to Latina principal identity formation including: a) Latina principals attribute family, cultural values, and mothering experiences as early influences that have positively impacted their personal identity development; b) Latina principals have unique and shared experiences related to adversity in their early schooling experiences and resistance; and c) Latina principals are creating spaces for their unique personal identity and experiences to inform their principal identity formation and leadership styles. The conceptual model titled Mestiza Principal Identity Formation is a symbolic representation of the construction of professional identity grounded in mothering practices, work ethic, and mestiza ethic of care.
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    Alternatively Certified (AC) Teachers' Perceptions and Understanding of Authentic Relationships
    (2022) Perez, Bryan James Paul
    Education as an institution has evolved from a private entity for the select few to a widespread social service provided to all. This has resulted in dramatic increases in enrollment and additional increases due to immigrants seeking opportunities, starting with schooling, in the United States. The combination of increased enrollment, fewer people enrolling in institutions of higher education to pursue careers in teaching, and an aging of the workforce has led to dramatic teacher shortages nationwide. Alternative certification (AC) programs were designed to fill this void; first addressing areas of high needs, often related to STEM-related courses. However, as the number of teachers needed to be increased, AC programs adapted to the times which allowed more diverse people to enter the profession in these non-traditional pathways. Yet supplying willing staff is only part of the educational equation; students comprise the other portion. As educators, we need to meet the students where they are when they come to school. Often times this means we are servicing students who have been impacted by adverse childhood experiences. The purpose of this study was to gain an understanding of alternatively certified teachers’ perceptions of being prepared to meet the social-emotional needs of potentially at-risk students. This qualitative study analyzed the lived experiences of four AC teachers employed in rural South Texas to gain insight into their induction process, and how they perceived their level of preparation and understanding in practices to support the social-emotional growth of their students.
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    Her Story, Her Voice
    (2022) Munoz, Monica Michelle
    This qualitative study acknowledged and highlighted the voices of three Chicana/Latina leaders including myself, who bear witness to one another as we shared our lived experiences of internal struggles, as we learned to navigate our identities. The purpose of this study was to critically examine how the lived experiences of the three leaders inform their practices at an all-girls school and their connection to critical consciousness and gender identity formation. To achieve this purpose, the study was guided by the research question: What are the experiences of Chicana/Latina leaders at an elementary all-girls school as their identity and leadership are shaped? The methodology employed in this research were testimonios which is grounded in the theoretical framework of Chicana Feminist Epistemology. The method used in this study were pláticas to provide space for each leader to share their story. Constructing knowledge collectively through testimonios provided space for each of our stories to be included in a narrative that is often told about us rather than with us. Findings demonstrated that stories of women past and present are critical in influencing identity; cultural identity spaces are needed to navigate personal and professional worlds; understanding and reflecting on cultural collision through assimilation experiences bridges oneself toward healing and transformation; creating space to inquire and define identity in schools breaks societal expectations; identity formation is a responsibility of educators to support and nurture; and Latina school leaders being vulnerable in storytelling to learn about one another's lived experiences with identity formation transforms school practices.
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    Building Self-efficacy in Novice Principals: An Exploration of Lived Experiences
    (2022) Hernandez, LeAnne
    The principalship is one of the most challenging roles in public education. The responsibilities are many. The political climate is stifling. The stressors are unmatched. A study by the Learning Policy Institute noted that nearly one in five principals were not in the same position one year later. The average tenure of principals in a school is four years, but one in three serve on a campus for less than two. (Levin & Bradley, 2019.) The COVID-19 pandemic has further strained an already struggling principal pipeline. Pre-COVID, principal turnover rates were alarming. DeMatthews et al. found that principals nearing retirement as well as principals with young children were more likely to resign their position during COVID than in years prior. (2022). Few novice principals feel adequately prepared to meet the demands of their position. (Clifford, 2015). However, some novice principals thrive despite the barriers before them. This study sought to understand the experiences, both personal and professional, that contributed to a novice principal's self-efficacy. The study focused on six novice principals. Each was a woman of color leading a successful Title I school in an urban setting in south Texas. The study sough to understand how, despite challenging circumstances, these ladies managed to lead schools with a focus on social justice and an unwavering commitment to equitable education for their students. Testimonios from each leader allowed them to share their story in their own words. This form of qualitative research centered the voice of the participant as the primary data source. Perez Huber described testimonio as a research methodology which includes a "verbal journey of a witness who speaks to reveal the racial, classed, gendered, and nativist injustices they have suffered as a means of healing, empowerment, and advocacy for a more humane present and future" (2009, p.644). Their testimonios revealed personal and professional instances of overcoming racial, gendered, and linguistic injustices in their lived experience. Each of these led to empowerment and self-efficacy. Themes were aligned with the four types of efficacious experiences outlined by Bandura: mastery experiences, vicarious experiences, verbal persuasion, and physiological experiences (1977). Implications for the field included considerations for both preparation programs and school district leadership development. Opportunities for future research are also discussed. In order to more effectively and equitably lead schools, the self-efficacy of principals toward social justice must be prioritized. The testimonios of social justice leaders provide insight and recommendations for system improvement.
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    La Presencia de los Padres: A Study of Parental Engagement in a South Texas Urban High School
    (2022) Garcia, Tina Marie
    This study aimed to debunk the traditional definition of parental engagement by hearing the voices of Latino parents to create a counter-story of the parental involvement myth. Because of our lack of engaging families of color in more authentic ways, we have perpetuated the mindset that diverse families in low socioeconomic areas do not value education. The problem is that a societal misconception is prevalent today that Latino parents do not participate in the education of their children. To challenge the deficit thinking culture, redefining parental engagement is necessary. Parental involvement refers to school-based practices such as attending school events and volunteering that are most often seen by educators. Parental engagement are those unseen actions Latino families partake in to support the children's school and life. In this qualitative study, three Latino parents participated in virtual pláticas for data collection. The following research question guided the research study: What are Latino parents' role perceptions, experiences, and motivating factors to parental engagement in a South Texas urban high school? Using Community Cultural Wealth (Yosso, 2005) as a framework, parents in this study support their children's learning in ""intentional and unintentional ways'' that teachers cannot see unless they will engage in purposeful conversations with individual families (Moll, Amanti, Neff, & Gonzalez, 1992; Williams, Tunks, Gonzalez-Carriedo, Faulkenberry, & Middlemiss, 2020, p. 491). The parental involvement and engagement practices were found in Latino households. Latino parents are not seen or acknowledged for contributing to their child's learning in and outside school. The leading factors for student success were the key findings that emerged from the Latino participants revealing that you do not have to be at school to be engaged or have an impact on children's educational trajectories. This is why Latino family engagement practices debunk the traditional definition of parental engagement. Latino parents' cultural parenting practices can be viewed as sources of strength and promise in schools when conceptualized through agency and engagement.
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    Microbial Source Tracking of a Stormwater Detention Basin Overlying the Edwards Aquifer Recharge Zone, San Antonio, Texas
    (2022) Flores, Mauricio Eduardo
    The Edwards Aquifer is the primary water resource for over 2 million people in Texas and faces serious challenges including fecal contamination of water recharging the aquifer. Fecal contamination enters hydrologic systems via failing septic systems, wastewater treatment plant effluent, and livestock waste facilities, among other sources. Effectiveness of best management practices (BMPs) such as detention basins in protecting water quality remains poorly understood. Fecal source identification is therefore crucial for implementation of BMPs that can mitigate pollution. Microbial source tracking (MST) has proven valuable in identifying contamination sources. For this study, the inlet and outlet of a detention basin overlying the aquifer's recharge zone were sampled following storm events using automated samplers. Quantitative polymerase chain reaction and IDEXX methods were used to quantify occurrence of MST markers and fecal coliform bacteria in collected water samples. Markers included those associated with E. coli (EC23S857), Enterococcus (Entero1), humans (HF183), canines (BacCan), and birds (GFD). Fecal coliforms, EC23S857, and Entero1 were detected following each storm event. GFD was the most frequent host-associated marker detected (91% of samples), followed by BacCan (46%), and HF183 (17%). Wilcoxon signed rank tests indicated significantly lower outlet concentrations for fecal coliforms, EC23S857, and Entero1, but not for HF183, GFD, and BacCan. Higher GFD and BacCan outlet concentrations may be due to factors independent of basin design, such as the non-point source nature of bird fecal contamination and domestic dog care practices in neighborhoods contributing to the basin. Mann-Whitney tests showed marker concentrations were not significantly higher during instances of E. coli water quality standard exceedance and that fecal coliform concentrations were not significantly different based on marker detection. Results suggest management efforts should focus on dog and bird-associated fecal pollution. Future work will investigate additional basins in the Edwards Aquifer Recharge Zone with varying land use regimes.
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    An Extraordinary Journey with Tert-butyl Nitrite and Diazo Compounds: from Nitrile Oxides to N-heterocycles
    (2022) De Angelis, Luca
    Terminal diazo compounds undergo smooth nitrosyl exchange with TBN to furnish nitrile oxides in situ after the loss of molecular nitrogen. Nitrile oxides are very useful reactive synthetic dipoles that dimerize to form furoxans or undergoes [3+2]-cycloaddition with alkenes or alkynes to generate isoxazoles and isoxazolines, respectively, in high yields. A different outcome was observed when vinyldiazo compounds and TBN were used. With these diazo compounds the nitrosonium ion intermediate did not undergo loss of dinitrogen, but instead underwent an intramolecular [5+1]-cycloaddition with the diazonium functionality to form 1,2,3-triazine 1-oxides in high yield. Thermal experiments revealed that the triazine 1-oxides are converted to isoxazoles with loss of dinitrogen in high yields. A new method for the synthesis of 5-alkyl and 5-aryl 1,2,3-triazine compounds was developed through the deoxygenation of triazine 1-oxides with trialkyl phosphites under moderate mild conditions. Based on previously report on the inverse electron demand Diels-Alder (IEDD) on symmetrical 1,2,3-triazine, the reaction occurs through a nucleophilic attack either at 4- or 6-position of the triazine core. Our triazine and triazine 1-oxide allow to differentiate those positions. In particular, the site of addition in triazines 1-oxide is the same that for 1,2,3-triazine in IEDD cycloadditions, and its mechanism occurs by C or N addition at 6-position followed by N2O/N2 elimination and cyclization pathways, but triazine 1-oxide exhibited an enhanced rate of product formation. In the triazine 1-oxide core the site of addition is reversed when TMSN3 was applied, which occurred at 4-position to form enoxime. The hydride from NaBH4 undergoes nucleophilic addition at 6-position on both triazine and triazine 1-oxide to obtain α-amino acid ester and 3,6-dihydro triazine 1-oxide, respectively. Reserve selectivity was observed when Hantzsch ester was used, and the hydride underwent selective nucleophilic addition at 4-position only on the 1,2,3-triazine-1-oxide to form enoxime in high yield and dr ratio. Alkoxides chosen as O-nucleophiles preferred the addition at the 4-position of triazine 1-oxide to obtain an oxime as one single geometrical isomer in high yield. Alternative sites of addition were observed on triazine and triazine 1-oxide when thiolate was used as a nucleophile. The site of nucleophilic addition with PhS- is at 6-position of the triazine, while it is at 4-position of the triazine 1-oxide. In the course of the latter investigations, we discovered that 1,2,3-triazine 1-oxides having an alkyl group containing a C-H bond at the 5-position undergo base promoted rearrangement to vinyldiazo oxime compounds that greatly expands access to diverse vinyldiazoacetates. A different reaction with TBN was observed with enoldiazoacetates. No loss of dinitrogen nor intramolecular cycloaddition was observed. Instead, the equivalent nitrosonium ion intermediate after silyl group-transfer generated unique compounds with 1,2,3,4-oxidized centers having vicinal 1-ester-2-diazo-3-keto-4-oxime functionalities. The treatment diazo oxime compounds with a dirhodium catalyst and water produced α-hydroxy carbonyl derivatives which are rapidly air oxidized to 1-ester-2,3-diketo-4-oxime compounds.
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    Optimal Coordination of Power Distribution Networks with Building Operations and Pump Scheduling in Water Distribution Systems
    (2022) Ayyagari, Krishna Sandeep
    Modern power distribution networks (PDNs) are gradually moving forward with new technologies such as control, communication, and metering to promote the concept of Smart Grids. Driven by initiatives such as US DOE Smart Grids, future distribution systems will facilitate the increased adoption of variable renewable generation, such as photovoltaic (PV) installations and wind turbines, as well as the integration of other critical infrastructures like building and water utilities. In such a setting, integrated control and optimization of such infrastructures would enhance optimal and secure operation, and reap socio-economic and environmental benefits. To this end, the majority of this dissertation aims to provide an optimization framework to coordinate power distribution networks with building operations and pump scheduling in water distribution networks.