Digital Commons Network^™

Contributions To The Heat Capacity Of Neutron Stars, Pedro Paulo Barboza Sanson

Theses and Dissertations

In this thesis, we review the contribution to the heat capacity of different matter phases that can appear inside a Neutron Star's core, paying special attention to the magnetic dual chiral density wave (MDCDW) phase, which is characterized by an inhomogeneous chiral condensate in the presence of a magnetic field and that is expected to be favored at intermediate densities and low temperatures. Furthermore, we compare our results with the observational lower limit of the core heat capacity established from observations of transiently accreting neutron stars which give us crucial information whether certain phases are feasible to appear in the …

Microwave Spectroscopy Of Cyclohexanecarboxylic Acid, Chlorosulfonic Acid, And Its Interaction With Water, Diego Erik Rodriguez

Theses and Dissertations

This study combines computational chemistry and microwave spectroscopy to simulate the behavior of two molecules: cyclohexanecarboxylic acid and chlorosulfonic acid. In this thesis, cyclohexanecarboxylic acid will be observed on its own. On the other hand, chlorosulfonic acid will be observed on its own as well as its interaction with one, two, and three water molecules. Chapter 1: Introduction will provide insight on published literature related to cyclohexanecarboxylic acid, chlorosulfonic acid, and perfluoroalkyl substances. Chapter 2: Computational Chemistry will provide the reader with information about the foundation of computational chemistry including theory and development of the science. Chapter 3: Microwave Spectroscopy …

Factors Influencing Intent To Take A Covid-19 Test In The United States, Sheila Rutto

Theses and Dissertations

In 2020, COVID-19 became the first pandemic in the world’s history that brought the entire world to an abrupt and unexpected halt. Since the first reported case of the disease to date, the novel coronavirus has been able to wreak havoc in literary every corner of the globe and left an ever-growing number of unprecedented fatalities. The normal way of life has been disrupted, and the level of uncertainty about the end of this pandemic continues to manifest to many. Due to the urgency to bring this pandemic under control, medical officers have been able to recommend actions that people …

A Hispanic-Serving Institution, Its Strategic Human Capital Utilization And The Shift In Institutional Culture After The Merger, Trini Yunes

Theses and Dissertations

In the United States, there has been recent attention to mergers involving higher education institutions. The fact is that mergers and acquisitions (M&A) are not a novel topic but more common in business. The paper will present the findings of a case study of the merger of two Hispanic-Serving Institutions (HSIs) in Texas and how leadership used both legacy cultures to create a new organizational culture. The main focus of this study is to compare the relationships, as viewed by staff and faculty, between institutional performance and organizational culture. It will also determine how human capital (HC) utilization is related …

Practical Wisdom As An Adaptive Algorithm For Leadership: Integrating Eastern And Western Perspectives To Navigate Complexity And Uncertainty, Mai P. Trinh, Elizabeth A. Castillo

Management Faculty Publications

In this paper, we integrate Eastern and Western perspectives of practical wisdom to answer the question, how can practical wisdom transfer across cultural boundaries in a world of increasing interconnection? We describe key properties of practical wisdom in early Western and Eastern schools of thoughts and explain how the concept of practical wisdom in ancient philosophy aligns with modern-day complex system science. We identify seven qualities of complex adaptive systems as a universal pattern that underlies both Eastern and Western perspectives. From these qualities, we develop an integrated conceptual framework of practical wisdom as factors both internal and external to …

Electrospun Polyetherimide And Polybenzimidazole Fibers And Composites, Fatema Ha-Mim Binta Hafiz

Theses and Dissertations

In this study, polymer micro- and nanocomposite fibers with PBI and PEI as polymer, and exfoliated graphite and nitroxide-functionalized graphene oxides have been prepared. Electrospinning has been chosen as a fiber processing technique. This work describes the electrospinning process of the mentioned polymer fibers and composite fibers followed by their characterization by XRD, ATR, SEM, TGA, DSC and Tensile testing.

Assessment And Monitoring Of Deltaic Wetlands And Fluvial Systems: Refining And Validating A Multimetric Index Of Resaca Ecosystem Health, David Lecusay Jr.

Theses and Dissertations

Resacas are ancient distributary channels of the lower Rio Grande River historically serving as floodwater drainage pathways onto the Laguna Madre, Texas. Resacas provide numerous ecosystem services and critical habitat for many species. Mainly influenced by urbanization, integrating a multimetric index for assessing and monitoring resaca ecosystem health is required for adaptive management. The Resaca Health Index (RHI) integrates structural and functional components: (1) nonredundant metrics describing fish communities (Fish Community Index); (2) Trophic State Index derived from Secchi depth; (3) decay constant from riparian vegetation leaf litter decomposing in the water column; and (4) a riparian quality index based …

Teacher Knowledge, Perceptions, And Language Orientations Towards Oral Language Instruction In A Dual Language Classroom, Lucy A. Montalvo

Theses and Dissertations

Dual language (DL) schools provide literacy in students’ native languages; however, it is unknown if there is a focus on oral language (OL) development, an essential component for emergent bilinguals’(EB) literacy development. The purpose of this mixed-methods case study is to understand what DL teachers in Virginia know about OL instruction when providing literacy instruction to EB students. This study also explored DL teachers’ perceptions and language orientations towards OL instruction in a DL classroom. The Holistic Biliteracy Framework by Escamilla et al. (2014) provided a research-based pedagogical model to compare teachers’ knowledge on OL instruction. The Language Orientation Framework …

Total Synthesis Of E Stereoisomers Of Bilirubin Oxidation Products, Tess C. Ruiz

Theses and Dissertations

The purpose of the research was to synthesize the E stereoisomer of Bilirubin Oxidation Products that had not been synthesized through a total organic synthesis at the start of this project. There were numerous different procedures for the bromination of citraconic anhydride performed in an attempt to optimize yield and purity. A proposed scheme for the total synthesis of the E isomers was constantly updated and altered while the project was ongoing. The bioactivity of the compounds was to be tested if the project had been finished. This might have contributed to a greater understanding of their function and association …

Improving The Success Of Non-Traditional Students In An Introductory Computing Course, Christine F. Reilly, Laura M. Grabowski, Gustavo Dietrich

Computer Science Faculty Publications

This Work in Progress Research to Practice paper presents a redesign of an introduction to computing course at a public, minority serving institution in the United States with a majority of non-traditional students. The course redesign was motivated by the desire to improve the success of the students in this course and in the major. Active learning during class and required attendance were the major components of the course redesign. The course policies included flexibility for the occasional absences that are expected with non-traditional students. A comparison of student performance in the experimental and control sections indicated that the requirement …

Combined Amplification And Sound Therapy For Individuals With Tinnitus And Coexisting Hearing Loss: A Retrospective Cohort Study, Purushothaman Ganesan, Hansapani Rodrigo, Jason Schmiedge, Rob Reiter, Simham Swapna, Vinaya Manchaiah

School of Mathematical & Statistical Sciences Faculty Publications

BACKGROUND: The heterogeneity of tinnitus perception and its impact necessitates a tailor-made management approach in everyone. The current study examined the effects of residual inhibition in combined amplification and sound therapy in individuals with tinnitus and coexisting hearing loss.

METHODS: A retrospective analysis was performed on patients with tinnitus and coexisting hearing loss between 2016 and 2019. A total of 72 patients provided with combined amplification and sound therapy were divided into 3 groups based on residual inhibition: (i) complete residual inhibition, (ii) partial residual inhibition, and (iii) negative residual inhibition. Tinnitus severity was measured using the Tinnitus …

On Inter-Organizational Trust, Control And Risk In Transboundary Fisheries Governance, Gordon M. Hickey, Hunter T. Snyder, Jasper R. Devries, Owen Temby

School of Earth, Environmental, & Marine Sciences Faculty Publications

Inter-organizational collaboration is often considered essential to transboundary fishery governance, due, in part, to the high levels of task interdependence, the remote and often treacherous conditions, and the limited levels of information available to any policy actor on resource status. In the high seas, Regional Fisheries Management Organizations (RFMOs) are responsible for sustainably managing highly migratory and straddling fish stocks through the implementation of ecosystem-based approaches and ensuring adequate inter-jurisdictional cooperation. A central question facing RFMO governance is therefore how to structure and sustain inter-organizational transboundary collaboration under high uncertainty? This paper presents the case of the North Atlantic Salmon …

Fast Reconfiguration Of Robot Swarms With Uniform Control Signals, David Caballero, Angel A. Cantu, Timothy Gomez, Austin Luchsinger, Robert Schweller, Tim Wylie

Computer Science Faculty Publications

This paper investigates a simplified model of robot motion planning where particles on a board respond to global signals, causing them to move uniformly in a particular direction. We consider two types of movement commands: (1) Steps, which cause particles to move one unit distance in the given direction, and (2) Tilts, which cause particles to move maximally in the given direction. Under the overarching theme of reconfiguring robot swarms, we look at the problem of assembling general shapes both within systems that exclusively use step commands and systems that exclusively use tilt commands. We derive upper and …

Dynamical Casimir Effect In A Superconducting Circuit Periodic Lattice, Andres Cuellar Vega

Theses and Dissertations

The dynamical Casimir effect (DCE) is the generation of real photons out of the quantum vacuum due to a rapid modulation of boundary conditions for the electromagnetic field, such as a mirror oscillating at speeds comparable to the speed of light. Previous work demonstrated experimentally that DCE radiation can be generated in electrical circuits based on superconducting microfabricated waveguides, where a rapid modulation of boundary conditions corresponding to semi-transparent mirrors is realized by tuning the applied magnetic flux through superconducting quantum-interference devices (SQUIDs) that are embedded in the waveguide circuits. We propose a novel SQUID periodic lattice architecture, in which …

Molecular Dynamics Study Of Atomic Diffusion In Cantor High Entropy Alloy In The Selective Laser Melting Process, Mathew Z. Farias

Theses and Dissertations

High entropy alloys (HEAs) are compositionally complex alloys that are comprised of 5 or more principle elements at near equimolar concentrations. The Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders, this process allows for the production of heterogeneous structures that would be difficult to create through more conventional means. In-situ alloying in SLM, or Laser Additive Alloying (LAA), using pure elemental powders is a promising means of producing what would otherwise be costly and difficult to fabricate products with less defects using prefabricated powders, therefore this new approach could enable the ability to …

Factors Affecting Irs Audit Rate Probability: Empirical Evidence From Rgv Region, Issack Guyo

Theses and Dissertations

IRS tax audits are intended to curb tax evasion; however, they are costly to conduct and have negative impacts on taxpayers. The purpose of this study is to find out factors that lead to high IRS audit rate in a region from the perspective of the Rio Grande Valley (RGV). Relationship between IRS tax audit rate and determinants of tax evasion identified by Davis, Cebula, & Boylan (2020) among others are studied. A regression analysis is conducted on the regions scores on poverty rate, demography, unemployment rate and general level of education with the IRS audit rate. The results suggest …

The Impacts And In-Depth Study Of The Environmental Contaminant, Perfluorooctane Sulfonic Acid, And Its Interactions With Water, Karla Veronica Salazar

Theses and Dissertations

Perfluorooctanesulfonic acid (PFOS), similar to perfluorooctanoic acid (PFOA), is a synthetic chemical that has been classified as a persistent organic pollutant (POP) by the Stockholm Convention since 2009. Due to the wide previous usage, high stability, high bio-accumulative, and low degradative properties is the reason that PFOS has been found in several compartments of the environment including ocean water, ground water, air, and sediments. Due to the strong interactions generated by the sulfonic acid end, this compound has a tendency to stay in the environment for long periods of time and has proved to be difficult in the removal from …

Managing Water Resource And Land Use In Lower Rio Grande Valley Of South Texas Using A Groundwater Vulnerability Model, Leslie Soto Sanchez

Theses and Dissertations

The Lower Rio Grande Valley (LRGV) has three Metropolitan Statistical Areas. These are Brownsville-Harlingen, Laredo, and McAllen-Edinburg-Mission, the latter with a population of around 1 million people and had an estimated growth of 62% from the period of 2010-2018 (Texas State Data Center, 2020). Low precipitations, intensive agricultures as well as growth in the manufacturing and tourism industries have resulted in an increasing concern of scarce water supply especially the region relies primarily on a single water source, the Rio Grande River. These circumstances could potentially disrupt economic development, negatively affecting the local manufacturing industry, agriculture, and the community. With …

A Statistical Comparison Of Covid-19 In The United States Across Political Affiliations And Census Regions, Margarito Torres

Theses and Dissertations

In mid-January 2020, the United States reported their first cases of the coronavirus disease (COVID-19) from a passenger returning from Wuhan, China. Initially, the situation wasn’t very alarming as in China and European countries, but the situation began to worsen in March 2020 when the number of cases began to multiply. Then, in a matter of a few months, the United States became the number one country in terms of total cases and total deaths from COVID-19. We have been closely observing the United States and the world since July 2020. Our study aims to compare the political affiliations and …

An Innovative Triboelectric Stent Sensor: Prospective Cardiovascular Health Monitor Device, Ulises Vidaurri Romero

Theses and Dissertations

Previous research that has focused on TENGs have lacked the proper application of this energy generator. Currently, heart disease remains the leading cause of death in the United States. With increasing demand for self-sustainable medical devices, this nitinol health monitor sensor device (NHMS) integrates the TENG applications with medical applications. The NHMS features memory shape nitinol electrodes that preserves the device structure while using PDMS and PVDF triboelectric effect to measure heart rate, blood pressure, and breathing patterns. Three constant pressures were measured in this study. At a constant pressure of stage 1, the NHMS produces an average AC of …

Identification And Characterization Of Bisbenzimide Compounds That Inhibit Human Cytomegalovirus Replication, Nicole Falci Finardi, Hyeongjun Kim, Lee Z. Hernandez, Matthew R. G. Russell, Catherine M-K Ho, Vattipally B. Sreenu, Hannah A. Wenham, Andy Merritt, Blair L. Strang

Physics & Astronomy Faculty Publications

The shortcomings of current anti-human cytomegalovirus (HCMV) drugs has stimulated a search for anti-HCMV compounds with novel targets. We screened collections of bioactive compounds and identified a range of compounds with the potential to inhibit HCMV replication. Of these compounds, we selected bisbenzimide compound RO-90-7501 for further study. We generated analogues of RO-90-7501 and found that one compound, MRT00210423, had increased anti-HCMV activity compared to RO-90-7501. Using a combination of compound analogues, microscopy and biochemical assays we found RO-90-7501 and MRT00210423 interacted with DNA. In single molecule microscopy experiments we found RO-90-7501, but not MRT00210423, was able to compact DNA, …

Polynomial Embeddings Of Unilateral Weighted Shifts In 2-Variable Weighted Shifts, Raul E. Curto, Sang H. Lee, Jasang Yoon

School of Mathematical & Statistical Sciences Faculty Publications

Given a bounded sequence omega of positive numbers, and its associated unilateral weighted shift W-omega, acting on the Hilbert space l(2) (Z+), we consider natural representations of W-omega as a 2-variable weighted shift, acting on the Hilbert space l(2)(Z(+)(2)). Alternatively, we seek to examine the various ways in which the sequence omega can give rise to a 2-variable weight diagram, corresponding to a 2-variable weighted shift. Our best (and more general) embedding arises from looking at two polynomials p and q nonnegative on a closed interval I subset of R+ and the double-indexed moment sequence {integral p(r)(k) q(r)(l) d sigma(r)}(k,l …

Smooth Loops And Loop Bundles, Sergey Grigorian

School of Mathematical & Statistical Sciences Faculty Publications

A loop is a rather general algebraic structure that has an identity element and division, but is not necessarily associative. Smooth loops are a direct generalization of Lie groups. A key example of a non-Lie smooth loop is the loop of unit octonions. In this paper, we study properties of smooth loops and their associated tangent algebras, including a loop analog of the Maurer-Cartan equation. Then, given a manifold, we introduce a loop bundle as an associated bundle to a particular principal bundle. Given a connection on the principal bundle, we define the torsion of a loop bundle structure and …

Trustworthy Medical Segmentation With Uncertainty Estimation, Giuseppina Carannante, Dimah Dera, Nidhal C. Bouaynaya, Rasool Ghulam, Hassan M. Fathallah-Shaykh

Computer Science Faculty Publications

Deep Learning (DL) holds great promise in reshaping the healthcare systems given its precision, efficiency, and objectivity. However, the brittleness of DL models to noisy and out-of-distribution inputs is ailing their deployment in the clinic. Most systems produce point estimates without further information about model uncertainty or confidence. This paper introduces a new Bayesian deep learning framework for uncertainty quantification in segmentation neural networks, specifically encoder-decoder architectures. The proposed framework uses the first-order Taylor series approximation to propagate and learn the first two moments (mean and covariance) of the distribution of the model parameters given the training data by maximizing …

Upconversion, Mri Imaging And Optical Trapping Studies Of Silver Nanoparticle Decorated Multifunctional Nagdf4:Yb,Er Nanocomposite, S. Yamini, M. Gunaseelan, Ajithkumar Gangadharan, Silverio A. Lopez, Karen S. Martirosyan, Agnishwar Girigoswami, Basudev Roy, J. Manonmani, Senthilselvan Jayaraman

Physics & Astronomy Faculty Publications

The multifunctional upconversion nanoparticles (UCNPs) are fascinating tool for biological applications. In the present work, photon upconverting NaGdF4:Yb,Er and Ag nanoparticles decorated NaGdF4:Yb,Er (NaGdF4:Yb,Er@Ag) nanoparticles were prepared using a simple polyol process. Rietveld refinement was performed for detailed crystal structural and phase fraction analysis. The morphology of the NaGdF4:Yb,Er@Ag was examined using high-resolution transmission electron microscope, which reveals silver nanoparticles of 8 nm in size were decorated over spherical shaped NaGdF4:Yb,Er nanoparticles with a mean particle size of 90 nm. The chemical compositions were confirmed by EDAX and inductively coupled plasma-optical emission spectrometry analyses. The upconversion luminescence (UCL) of NaGdF4:Yb,Er …

Methodological Challenges In Studying Trust In Natural Resources Management, Antonia Sohns, Gordon M. Hickey, Jasper R. De Vries, Owen Temby

School of Earth, Environmental, & Marine Sciences Faculty Publications

Trust has been identified as a central characteristic of successful natural resource management (NRM), particularly in the context of implementing participatory approaches to stakeholder engagement. Trust is, however, a multi-dimensional and multi-level concept that is known to evolve recursively through time, challenging efforts to empirically measure its impact on collaboration in different NRM settings. In this communication we identify some of the challenges associated with conceptualizing and operationalizing trust in NRM field research, and pay particular attention to the inter-relationships between the concepts of trust, perceived risk and control due to their multidimensional and interacting roles in inter-organizational collaboration. The …

Binational Reflections On Pathways To Groundwater Security In The Mexico–United States Borderlands, Rosario Sanchez, José Agustin Breña-Naranjo, Alfonso Rivera, Randall T. Hanson, Antonio Hernández-Espriú, Rick J. Hogeboom, Anita Milman, Jude A. Benavides, Adrian Pedrozo-Acuña, Julio Cesar Soriano-Monzalvo

School of Earth, Environmental, & Marine Sciences Faculty Publications

Shared groundwater resources between Mexico and the United States are facing unprecedented stressors. We reflect on how to improve water security for groundwater systems in the border region. Our reflection begins with the state of groundwater knowledge, and the challenges groundwater resources face from a physical, societal and institutional perspective. We conclude that the extent of ongoing cooperation frameworks, joint and remaining research efforts, from which alternative strategies can emerge, still need to be developed. The way forward offers a variety of cooperation models as the future offers rather complex, shared and multidisciplinary water challenges to the Mexico–US borderlands.

Magnetic Dual Chiral Density Wave: A Candidate Quark Matter Phase For The Interior Of Neutron Stars, Efrain J. Ferrer, Vivian De La Incera

Physics & Astronomy Faculty Publications

n this review, we discuss the physical characteristics of the magnetic dual chiral density wave (MDCDW) phase of dense quark matter and argue why it is a promising candidate for the interior matter phase of neutron stars. The MDCDW condensate occurs in the presence of a magnetic field. It is a single-modulated chiral density wave characterized by two dynamically generated parameters: the fermion quasiparticle mass m and the condensate spatial modulation q. The lowest-Landau-level quasiparticle modes in the MDCDW system are asymmetric about the zero energy, a fact that leads to the topological properties and anomalous electric transport exhibited by …

Pre-Sowing Treatments Improve Germinability Of South Texas Native Plant Seeds, Kaitlynn Lavallee, Pushpa Soti, Hansapani Rodrigo, Rupesh R. Kariyat, Alexis Racelis

School of Earth, Environmental, & Marine Sciences Faculty Publications

The incorporation of native plant species is central to restoration efforts, but this is often limited by both the availability of seeds and the relatively low viability and germination rates of commercially available seeds. Although pre-sowing treatments are commonly used to improve germination rates of seeds, the efficacy of these treatments is found to vary across species. In this study, we tested how four pre-sow treatments (physical scarification, acid scarification, cold stratification, and aerated hydropriming) affected the viability and seed germination rates of 12 commercially available plant species native to south Texas and commonly used in restoration efforts. Our results …

Piezoelectric Signals In Vascularized Bone Regeneration, Delfo D’Alessandro, Claudio Ricci, Mario Milazzo, Giovanna Strangis, Francesca Forli, Gabriele Buda, Mario Petrini, Stefano Berrettini, M. Jasim Uddin, Serena Danti, Paolo Parchi

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The demand for bone substitutes is increasing in Western countries. Bone graft substitutes aim to provide reconstructive surgeons with off-the-shelf alternatives to the natural bone taken from humans or animal species. Under the tissue engineering paradigm, biomaterial scaffolds can be designed by incorporating bone stem cells to decrease the disadvantages of traditional tissue grafts. However, the effective clinical application of tissue-engineered bone is limited by insufficient neovascularization. As bone is a highly vascularized tissue, new strategies to promote both osteogenesis and vasculogenesis within the scaffolds need to be considered for a successful regeneration. It has been demonstrated that bone and …