Digital Commons Network^™

Detecting Snake Fungal Disease (Ophidiomyces Ophiodiicola) In The Lower Rio Grande Valley, Manuel Zavala

Theses and Dissertations

Emerging diseases such as Snake Fungal Disease (SFD) caused by the fungus Ophidiomyces ophiodiicola (Oo) have caused population declines in various snake species in the United States which play a crucial role in the ecosystem as a natural pest control. This fungus targets the scales as a medium to thrive on which can lead to facial disfiguration and respiratory infections. We examined snakes to see if SFD was present in the LRGV and if other fungal species pose a threat to the various snake species population. The data for this study consisted of 14 live snakes captured in …

Electro-Optic Satellite Constellation Design Using Multi-Objective Genetic Algorithm, Yasin Tamer

Theses and Dissertations

Satellite constellation design is a complex, highly constrained, and multidisciplinary problem. Unless optimization tools are used, tradeoffs must be conducted at the subsystem level resulting in feasible, but not necessarily optimal, system designs. As satellite technology advances, new methods to optimize the system objectives are developed. This study is based on the development of a representative regional remote sensing constellation design. This thesis analyses the design process of an electrooptic satellite constellation with regional coverage considerations using system-level optimization tools. A multi objective genetic algorithm method is used to optimize the constellation design by utilizing MATLAB and STK integration. Cost, …

Discerning Competitive Vs. Facilitative Relationships Of Weeds On Forest Restoration Efforts At La Sal Del Rey, Tx, Mylen A. Arias

Theses and Dissertations

Dryland ecosystems need effective restoration strategies to address severe degradation. It is often assumed that voluntary forb weeds either compete with or have no effect on native seedlings. In contrast, theory and empirical work suggest a potential facilitative role for such forb weeds. We conducted a manipulative weed exclusion experiment at a semi-arid site in South Texas targeted for large scale forest restoration and subsequently dominated by early successional forb weeds to discern the net effect of these weeds on the growth and survival of target thornscrub tree and shrub seedlings. Overall, weed presence did not significantly affect seedling mortality …

A Python-Based Brain-Computer Interface Package For Neural Data Analysis, Md Hasan Anowar

Theses and Dissertations

Anowar, Md Hasan, A Python-based Brain-Computer Interface Package for Neural Data Analysis. Master of Science (MS), December, 2020, 70 pp., 4 tables, 23 figures, 74 references.

Although a growing amount of research has been dedicated to neural engineering, only a handful of software packages are available for brain signal processing. Popular brain-computer interface packages depend on commercial software products such as MATLAB. Moreover, almost every brain-computer interface software is designed for a specific neuro-biological signal; there is no single Python-based package that supports motor imagery, sleep, and stimulated brain signal analysis. The necessity to introduce a brain-computer interface package that …

Performance And Efficiency Evaluation Of Stormwater Management Lids Using Pcswmm: Numerical Modeling And Sensitivity Analysis, Abdullah Al Fatta

Theses and Dissertations

Implementation of Low Impact Development systems (LIDs) can reduce the detrimental effects of urbanization. In this study, performance of both conventional drainage system and bioretention swales LID green infrastructure was assessed. Personal Computer Storm Water Management Model (PCSWMM) was used to investigate the performance by producing runoff hydrographs. Calibration and validation were conducted with independent storm events to minimize the gap between the simulated and observed outflow. Among different sensitive parameters, saturated hydraulic conductivity, suction head, percent initially saturated, Manning’s N for impervious area, were used in calibration. Each storm event resulted coefficient of determination (R2) values of 0.656 or …

A Lake Divided: Regional Shifts In Trophic Niche Structure Of Lake Powell Fishes Corresponding To The Invasion Of Quagga Mussels, Nathan Richard St Andre

Theses and Dissertations

Introduced species can become invasive and cause catastrophic alterations to the system they invade. Both zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena bugensis) have caused significant ecosystem alterations wherever they have invaded. These Dreissena species have caused changes in water quality and biodiversity and have disrupted energy pathways which can have cascading effects on other trophic levels. Recently quagga mussels invaded Lake Powell, a reservoir located in the southwestern USA, creating the possibility of a trophic cascade that could alter energy flow in the reservoir and change the trophic niche structure of the fishes in the lake. However, due …

3d Printed Microporous Collagen Constructs Using The Freeze-Fresh Methodology, Thais Sousa Senzano

Theses and Dissertations

Scaffold microporosity is known to play a critical role in governing cellular response including cell migration, proliferation, and tissue-specific differentiation. While fabrication approaches such as solvent leaching and freeze-casting are commonly used for the generation of microporous biomaterial scaffolds, these methods provide little control over scaffold geometry and creation of complex tissue structures. Extrusion-based 3D printing, an additive manufacturing method, is a highly versatile layer-by-layer printing approach that allows for the fabrication of easily customizable 3D scaffolds with complex architecture using a vast selection of polymeric bioinks. These 3D printed constructs are porous at the macroscale, but achieving microporosity (i.e., < 100 μm) in printed constructs is challenging due to the sub-optimal resolution of the extrusion-based printing method. A recent study using alginate inks introduced a new fabrication technique termed Freeze-FRESH(FF)that combines extrusion printing and freeze-casting approaches to generate 3D constructs with hierarchical microporosity. However, the porosity of the resultant alginate constructs was comparable despite changing the freezing temperature. In the current study, the FF method was modified to print collagen constructs with greater control of microporous architecture. Highly concentrated collagen type I ink was used to 3D print collagen constructs using the freeform reversible embedding of suspended hydrogels (FRESH)approach. Modification of the FF technique entailed melting of the FRESH bath post printing via incubation at 37 °C followed by freezing and lyophilization to allow for collagen gelation and better heat transport during the freezing process. The effect of freezing temperature on micropore size, swelling degree, degradation, and mechanical properties of printed constructs was assessed. Finite element (FE) models were generated to predict the mechanical properties of microporous scaffolds. In addition, the effect of microporosity on Saos-2 cell morphology, proliferation, infiltration, and ALP activity was evaluated. Results from the study showed that freezing temperature effectively modulated micropore size and that constructs with larger micropore size were more stable. Microporosity had no effect on swelling ratio yet caused a decrease in mechanical properties of collagen constructs; FE models confirmed experimental results. Cell metabolic activity and infiltration was enhanced in microporous constructs with larger pore size, yet there was no effect on cell morphology, and ALP activity. In conclusion, the modified FF technique can be effectively used to fabricate hierarchically porous 3D collagen constructs.

Optimization Framework For Reconstructing Biomedical Images By Efficient Sample-Based Parameterization, Paul Richard Arbic Ii

Theses and Dissertations

An efficient computational approach for optimal reconstruction of binary-type images suitable for models in various biomedical applications is developed and validated. The methodology includes derivative-free optimization supported by a set of sample solutions with customized geometry generated synthetically. The entire framework has an easy to follow design due to a nominal number of tuning parameters which makes the approach simple for practical implementation in various settings, adjusting it to new models, and enhancing the performance. High efficiency in computational time is achieved through applying the coordinate descent method to work with individual controls in the predefined custom order. This technique …

A Finite State Automata-Based Description Of Device States For Function Modeling Of Multi-State Technical Devices, Ahmed Mohammed Sobhan Chowdhury

Theses and Dissertations

Many modern and innovative design problems require multi-modal, reconfigurable solutions. Function modeling (FM) is a common tool used to explore solutions in early stages of mechanical engineering design. Currently, function structure representations do not abet the modeling of formally-defined reconfigurable function models as graph-based function models used in early-stage systems design usually represent only one operational mode of the system. Currently there is a need, but no rigorous formalism to model multiple possible modes in the model and logically predict the behavior of the system as it transitions between the modes. Additionally, function modeling representations will benefit from dynamically capturing …

Mathematics That Clarify Slope & Scale, Help Set Standards, And Improve Interrater Agreement On Time-Series Graphs, Chad Erick Liming Kinney

Theses and Dissertations

This paper introduces new mathematic equations that clarify slope and scale and help overcome difficulties with visually interpreting slopes (or trends)--a significant culprit of poor interrater agreement (IRA) of graphed data. Three experiments tested applications of the equations and demonstrated the following results: (a) Graphic Variability Quotient (GVQ) manipulation strongly predicts viewer ratings (and accuracy) of behavior change, β = .895, R2 = .801, (b) mathematical standards that control the inherent variability in non-standard graphs can be empirically based (to facilitate reliable visual comparison), and (c) visual aids posted on graphs, such as angles of inclination and a simple slope …

Biometric Face Skintone Data Augmentation Using A Generative Adversarial Network, Rosalin Dash

Theses and Dissertations

Researchers seek methods to increase the accuracy and efficiency in identifying an individual using facial biometric systems. Factors like skin color, which may affect the accuracy of facial recognition, need to be investigated further. To analyze the impact of race with respect to skin color of face on biometric systems, we focused on generating a dataset with uniformly distributed images of different skin tones while preserving identities. Deep learning neural network architectures like the generative adversarial network (GAN) focus on modifying only certain features of the face like the color of the skin. In our experimental approach, we implemented a …

Developing Methods To Survey, Collect, Process, And Screen Endemic Entomopathogenic Fungi Against The Asian Citrus Psyllid In The Lower Rio Grande Valley, Jonathan Cisneros

Theses and Dissertations

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), vectors “Candidatus Liberibacter spp.”, the causative agent of Citrus Greening Disease. Managing ACP is imperative given the continuous increase in HLB positive trees. An aspect of integrated pest management (IPM) is the use of entomopathogenic fungi for the biological control of D. citri.

In order to identify endemic entomopathogenic fungi actively infecting D. citri, ACP were collected from local residential areas, surface sterilized, and plated on a semi-selective agar medium. Collection of over 9,300 samples from 278 sites throughout the LRGV led to the positive identification of …

Chemical Investigation Of Avocado (Persea Americana) Seed Husk (Testa): A Waste Of Waste, Orlando A. Castillo Scheren

Theses and Dissertations

Food chemistry is a new field in the world and is currently still expanding into the types of market in which it can be tapped into. There are about 1.3 billion tons of food waste produced in 2016 in the world, and food chemistry is going to help get rid of that waste by finding new and exciting applications to the things currently considered as waste. In these products, there might be new and undiscovered drugs that can be used in the market to help treat diseases for which might not have a cure at the current moment. The avocado …

Synthesis, Characterization, And Application Of Meso-Tetraphenyl Metalloporphyrin Photocatalysts Under Visible Light, Alexis Echavarria

Theses and Dissertations

The photocatalytic activity of meso-Tetraphenyl Metalloporphyrins with different metal centers was investigated. The synthesized metalloporphyrin photocatalysts was performed and analyzed using FT-IR spectroscopy, UV-VIS spectroscopy, and powder X-Ray Diffraction analysis. The synthesized TPP crystals were determined to be tetragonal crystal structure and the structure was observed in all synthesized metalloporphyrin catalysts. The Soret (B) bands, Q bands, FT-IR functional groups were identified. Reaction progress was investigated by sampling at intervals of one hour and analysis of the samples was performed using Gas Chromatography-Mass Spectrometry. GC-MS analysis was used to identify the products of the photochemical catalytic redox reactions performed under …

Disturbance, Defense And Fitness In Silverleaf Nightshade (Solanum Elaeagnifolium) In Their Native Range In South Texas, Jesus Chavana

Theses and Dissertations

The role of human disturbance in accelerating weed growth is well understood. While most of these studies have focused on soil mediated disturbance, mowing is also a management practice that could impact weed traits. Using silver leaf nightshade (Solanum elaeagnifolium), a noxious and invasive weed, we asked whether continuous mowing affects growth and plant defense traits. We found that mowed plants produced significantly less fruits, had lower total seed fitness, but had higher seed mass, and germinated significantly faster. When three common herbivores were allowed to feed on the seedlings; tobacco hornworm (Manduca sexta), a generalist Solanaceae caterpillar gained more …

The Relationship Between The 9th Grade State Assessment And Extra Curricular School Activities And Gender For Disadvantaged Hispanic Students In South Texas, Paz Elizondo Jr.

Theses and Dissertations

The purpose of this study is to analyze the relationship between the 9th grade state assessment test scores for Disadvantaged Hispanic students who are taking the English I State of Texas Assessment of Academic Readiness End-of-Course exam. The group analyzed was comprised of the 2016-2017 cohort students from a South Texas High School.

Attitudes Of Criminal Justice Students' Towards Women: Hegemonic Masculinity In The Workplace, Lauren Escovedo

Theses and Dissertations

The purpose of the following study is to examine positive, benevolent, and hostile attitudes towards women in the workplace held by criminal justice students enrolled at the University of Texas Rio Grande Valley. As well, to examine whether or not criminal justice students enrolled at the University of Texas Rio Grande Valley believe that criminal justice personnel create a gender-neutral classroom environment. The application Qualtrics XM was used to comprise a 35 question survey that, as a result of the COVID-19 pandemic, was administered online to students for a two week period during the Fall 2020 semester. Criminal justice students …

Role Of Herbivore Associated Elicitors In Plant Defense Signaling, Akanksha Gandhi

Theses and Dissertations

Chapter 2: In this chapter, I have provided an update on recent developments and advances on early signaling events in plant-herbivore interactions, with a particular emphasis on the membrane potential changes (Vm), calcium (Ca2+), reactive oxygen species (ROS) and plant ion channels involvement in early signaling events initiation and propagation of defense signaling cascade.

Chapter 3: In this chapter, we show that tobacco hornworm (Manduca sexta) caterpillar oral secretion (OS) induces ROS in tomato (Solanum lycopersicum) protoplasts. By using a dye-based ROS imaging approach, our study showed that the application of Plant-Fed (PF) M. sexta OS …

Exploring The Implementation Of A Proficiency-Focused, Performance-Based Approach In Foreign Language Teaching, Yuka Kato

Theses and Dissertations

Foreign language teachers in one district faced a paradigm shift in the ways language should be taught and in their pedagogical beliefs. They were asked to shift from a traditional approach to the Proficiency-Focused, Performance-Based (PFPB) approach in order to meet the national Standards for Foreign Language Learning in the 21st Century, created by ACTFL (1999 & 2006). The expectation was that every foreign language teacher in the district would use the PFPB approach. However, the problem was that some of the teachers would not understand the approach or how to implement it, with the result that the approach …

Interactive Effects Of Heat Stress And Pesticides Co-Exposure On Swimming Behavior, Oxidative Stress, Antioxidant Expression, And Redox Status In Common Goldfish (Carassius Auratus), Brittney Danielle Lacy

Theses and Dissertations

Aquatic ecosystems are inundated by environmental pesticides. This study, observed the dose-dependent effects of pesticides cocktail (metalachlor, linuron, isoproturon, tebucanazole, aclonifen, atrazine, pendimethalin, and azinphos-methyl) and elevated temperature (32 °C for 4-week exposure) on morphology of gills and kidneys, and expression of nitrotyrosine protein (NTP), dinitrophenyl protein (DNP), catalase (CAT), superoxidase dismutase (SOD), Na+/K+-ATPase, renin, and apoptosis in tissues of goldfish. Additionally, the effects on the free-swimming behavior were also observed. Histological analysis showed wide-spread damage in tissues at higher temperature and pesticides co-exposure. Immunohistochemical analysis demonstrated alterations in NTP, DNP, CAT and SOD expressions in tissues at higher temperature …

On Coupled Reaction Diffusion Equations And Their Applications, Juan J. Huerta

Theses and Dissertations

Reaction-diffusion equations are nonlinear partial differential equations that have been used extensively in mathematical modeling. An interesting case in this type of equation is the Fisher-Kolmogorov system, which has been used to study a low-grade glioma, a group of primary brain tumors. In the first part of this thesis, a stochastic version of the Fisher-Kolmogorov system will be studied, and exact and numerical solutions will be presented.

The second part of this thesis will show how the speed of information propagation affects disease spread and vaccination uptake through networks in epidemics. In this model, the information reaches different people at …

Incorporation Of Native Plants For Biodiversity Conservation In South Texas Agroecosystems, Kaitlynn M. Lavallee

Theses and Dissertations

I address the concerning disconnect between food production and regenerative ecological principles. First, understanding the foundational processes of seed-dormancy and germination are essential for successful restoration efforts using native species. We examine four common seed treatments (aerated hydroprime, acid scarification, cold stratification, sand scarification) on twelve commercially available species native to south Texas. Pappophorum bicolor Fourn. (pink pappusgrass) was sown in the field with the aerated hydroprime treatment, D. virgatus (Willd.) B.L. Turner (prostrate bundleflower) was planted after sand scarification treatment, and Ratibida columnifera (Nutt.) Woot. & Standl. (Mexican hat) was seeded without treatment. Small-scale field trials were conducted to …

Examining The Indoctrination Of Mexican American Criminal Justice Students, Noe Leal Jr.

Theses and Dissertations

Mexican American Criminal Justice students (MACJS) sometimes select a career in Department of Homeland Security, which has a history of systemic racism and oppression. The purpose of this thesis is to examine MACJS conformity to U.S. ideological hegemony and examine the differences in their understanding of human rights/ethics. A questionnaire was administered to MACJS (n = 156) wishing to pursue a career in DHS. The survey instrument used is based on the concepts of Social Identification: Mexican versus U.S. American; Support for Nationalist Racist Policies, Internal Colonialism, Followership by engaging in policies/orders by the government; and Human Rights: Knowledge of …

A Darker Shade Of Gray: An Empirical Examination Of Gray Swans In The Supply Chain, Tony N.K. Lynch

Theses and Dissertations

The complexity and interconnectedness of markets creates risks in the global supply chain and may lead to various types of disruptions. Prior research in the supply chain management literature has focused on some aspect of disruption and firm performance. However, the effect of Gray Swans on various aspects of firms’ operational or financial performance is an under-research area. Understanding why managers often underestimate and overlook Gray Swans contributes to ongoing conversation of risk in the global supply chain. Gray Swans are defined as low probability risk events that if/when they occur can have a severe or catastrophic impact on a …

Electromagnetic Interference Shielding Effectiveness Of Interlayered Systems Containing Metal-Oxide, Conducting Polymer And Carbon Nanotube Reinforced Polymeric Composites, Shaik Merkatur Hakim Marjuban

Theses and Dissertations

The Electromagnetic Interference (EMI) Shielding Effectiveness (SE) has become one of the important requirements for the devices associated with telecommunication systems consisting of large frequency bands. The degradation of the quality of transmitting signal influenced by frequencies emitting from external sources can be reduced by covering the circuits of the devices by EMI Shielding materials like polymer composites, metal-based nanofiber mats, the metal of oxide films, etc. The investigation strives for the attenuation of EMI by introducing two composite mats from conducting polymer-based, multiwalled carbon nanotubes (MWCNTs) coated Nylon 6 nanofiber composites. Two other composite mats are also developed by …

Association Study: Apoe Alleles Association With Neurodegenerative Disorders In The Hispanic Population, Kimberly Moreno

Theses and Dissertations

The purpose of this study was to assess the impact of phenotypic variables and Apolipoprotein E (APOE) alleles and its effect on cognitive statues. APOE is a gene found vastly in the Hispanic community, speculated to be linked to neurodegenerative disorders such as Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI). Compared demographic, clinical, and genetic features among Hispanics who were diagnosed with Alzheimer's Disease, Mild Cognitive Impairment, and psychiatric disorders (e.g., anxiety and depression) in the efforts to assess the role of APOE. In past research, APOE has been considered a pathological hallmark for neurological diseases.

Past research has …

Thermal And Spectroscopic Investigations On Polymer-Based Nanofibers, Omosola Oriretan

Theses and Dissertations

Nanofibers of Poly (ethylene oxide), PEO, Poly (vinylpyrrolidone) PVP, Co-nanofiber of PEO-PVP and PEO nanocomposite of various Fullerene compositions were prepared by dissolving PEO, PVP and Fullerene in water. The Fullerene nanoparticles were added to the PEO solutions, the mixtures were homogenized under high power sonication. The PEO solutions, PVP solutions, the co-polymer solutions of PEO-PVP and the PEO -Fullerene solutions were centrifugally spun using Force spinning™ machine. The obtained nanofibers and the nanocomposites were subjected to FTIR analysis, Raman analysis and various heating and cooling cycles with heating and cooling rates ranging from 10C/min to 600C/min using differential scanning …

Infection And Persistence Of Zika Virus In Female Immune-Competent Gray Short-Tailed Opossums (Monodelphis Domestica), Oscar Quintanilla

Theses and Dissertations

Zika virus (ZIKV) is a class IV RNA virus transmitted by Aedes species of mosquitoes. It produces flu-like symptoms, but recent studies have associated additional, more severe pathologies with ZIKV like microcephaly. Currently, no effective treatment options or vaccines exist. This is partly due to limitations of current animal models. Monodelphis domestica (the gray short-tail opossum) may serve as a proper model for ZIKV research. Here we test the susceptibility of M. domestica to ZIKV infection. Female, immune-competent subjects were injected with live ZIKV and analyzed serologically and histologically for evidence of ZIKV replication. ELISAs performed on sera confirmed that …

Chemical Modification And In Silico Validation Of Medicinally Privileged Molecular Scaffolds As Kras And Sars-Cov-2 Protease Inhibitors, Precious M. Okwuchukwu

Theses and Dissertations

Coronavirus disease was declared a global pandemic by WHO in March 2020, cancer is the second leading cause of death by a disease. Several scientists around the world are working relentlessly to discover an effective remedy to eradicate these deadly diseases. A natural polyphenol (magnolol) has been isolated from a tree Magnolia grandiflora (family Magnoliaceae) found on UTRGV campuses. This research is focused on design of a series of chemically modified sulfonyl derivatives based on the isolated magnolol framework and other medicinally privileged molecular scaffolds framework that can effectively bind to the COVID-19 main protease, SARS- CoV-2 3CL protease …

Effects Of Elevated Temperature On 8-Hydroxy-2'-Deoxyguanosine Expression, Dna Damage And Cellular Apoptosis In The American Oyster (Crassostrea Virginica), Md Faizur Rahman

Theses and Dissertations

Global temperature increases due to anthropogenic activities. The effects of rising temperature are well documented in aquatic organisms. The American oyster is an ideal shellfish species to study on global warming and oxidative DNA damage. In this study, We observed the effects of high temperature on heat shock protein-70 (HSP70), 8-hydroxy-2’-deoxyguanosine (8-OHdG), ssDNA, dsDNA, caspase-3 (CASP3), BAX and γH2AX, a molecular marker of DNA damage, protein expressions in gills of oysters. Immunohistochemical results showed that elevated temperatures (28 and 32°C) significantly increased HSP70, 8-OHdG, dsDNA, γH2AX, BAX and CASP3 protein expressions in gills of oysters compare to control (24°C). In …