Digital Commons Network^™

Consequences Of Math Anxiety And Stereotype Threat: An Intersectional Perspective, Jennifer E. John Buck

UNLV Theses, Dissertations, Professional Papers, and Capstones

Individuals with science, technology, engineering, and math (STEM) skills are highly valued for their contribution to the U.S. workforce and society. However, women and some people of color enter STEM fields at lesser rates than do White men. Math anxiety and stereotype threat have been found to cause math performance decrements for women and some people of color. Presently, it is not clear how math anxiety and stereotype threat might work together to dually influence math performance and subsequent STEM participation. The current study focuses on a diverse sample of 295 undergraduate students who were randomly assigned to one of …

On Muddy Banks: An Ecoethnography Of A River Island Community, Nicholas Baxter

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study, I examine the relationship between a river and a community. Specifically, I analyze the processes and patterns that organize the nature-society relationship and define the river town of Sabula, IA. To guide my historical and ethnographic analysis, I utilize a co constructionist posture (Rice 2013), which sees culture, community, economy, and physicality as much a product of bio-physical forces as social forces. My aim is to understand how Sabula is conjointly constructed and reveal the nuanced interconnections between human communities and nature through which social and environmental problems play out. My analysis clarifies patterns in residents’ identity …

International Faculty’S Lived Experience Of Teaching: A Multiple-Case Study Of Taiwanese Professors In The United States, Ching Hsu Kim

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the context of higher education, a tenure-track faculty is expected to be actively engaged in scholarly activities including research, teaching and service activities. Finding a balance between personal and career lives is seen critical yet challenging especially to early-career international faculty members while they are in the face of differences and changes. Framed by theories of perezhivanie and resilience, the study examined international faculty members’ lived experiences of teaching. Interviews, blog prompts and reflection prompts were used to identify their major difficulties, perceptions and adjustments, and resilience development. Findings suggest that faculty members unavoidably encountered difficulties in their beginning …

Moisture Dynamics Of A Near-Surface Desert Soil, Yuan Luo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Desert soils cover about one third of the Earth’s land surface. Despite their large extent, however, our understanding of desert soil hydraulic processes and properties is still rather limited. In particularly with respect to the near-surface (top centimeters) of the soil profile, which play a critical role for infiltration, redistribution and evapotranspiration of rainwater, the limiting resource for life in desert environments, but also hosts most of the biologic activity and controls runoff, erosion as well as the emission of dust (Nannipieri et al.,2003; Bradford et al.,1987). Additionally, deserts are ideal locations for electricity generation with solar energy using large-scale …

Utility Of Bench Scale Sand Tank Experiments At Assessing Permeable Reactive Barrier Design, Brandon Meier

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this work was to evaluate the utility of bench scale sand tank experiments at assessing permeable reactive barrier (PRB) design. Our criteria for meeting this goal was that differences between PRB designs could be identified solely by measuring concentration in outflow from the sand tank models. For our PRB designs (funnel-and-gate, staggered wells, and parallel bars), numerical simulations clearly showed that PRB design had a quantifiable effect on outflow concentration, provided that the solute reacted with the PRB materials. Conversely, use of a conservative (non-reactive) solute did not allow us to discern between PRB design alternatives. Employing …

Alkali-Silica Reactivity Of Mortars Containing Natural Pozzolan, Arash Kian

UNLV Theses, Dissertations, Professional Papers, and Capstones

Alkali-silica reactivity is one of the most recognized deleterious phenomena in Portland cement concrete resulting in cracks, spalling, and other deleterious mechanisms.

The aim of this study was (i) to assess the extent of reactivity of the aggregates, quarried from seven different sources, suspected of being conducive to ASR, and (ii) to compare the effectiveness of industrial (Class F fly ash) and natural pozzolans in mitigation of alkali-silica reactivity of the studied aggregates. To this end, seven aggregate sources, four natural pozzolan sources, and one source of Class F fly ash were used. ASTM Type V Portland cement was replaced …

Cfd Simulation Investigating The Effects Of Groove Geometry On Heat Transfer For Internally Grooved Tubes, Richard Zaven Saroukhanoff

UNLV Theses, Dissertations, Professional Papers, and Capstones

This numerical study investigates the thermal performance of internally grooved tubes used in heat exchangers. In order to enhance the performance of heat exchangers, turbulence promoters are inserted along the streamwise flow. The use of inserts, grooves, and augmentations along the axial length of the tube creates disturbances that improve the overall heat transfer due to enhanced fluid mixing and greater surface contact boundary walls. However, the implementation of tube wall augmentations creates an increase in pressure drop across the tube which must be compensated for with additional pumping power for the working fluid. Therefore, in order to analyze the …

Design Of Efficient Carbon-Based Adsorbents For The Removal Of Organic And Inorganic Water Contaminants, Sayedeh Soroosh Mortazavian Dehkordi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Granular activated carbon (AC) and biochar (BC) are two carbon-based adsorbents commonly used for water and wastewater treatment. However, these adsorbents have drawbacks that suppress their aqueous contaminants removal efficiency. Their major disadvantages are that AC has low selectivity and reusability potential, and BC has a hydrophobic nature.

The scope of this dissertation is to enhance the performance of commonly-used carbon-based adsorbents for the removal of organic and inorganic water contaminants and to understand the interactive mechanism of contaminants’ ions/molecules with adsorbents. Hexavalent chromium (Cr(VI)) and trichloroethylene (TCE) are two types of inorganic and organic water contaminants, respectively, which are …

High-Speed Radhard Mega-Pixel Cis Camera For High-Energy Physics, Wenlan Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation describes the schematic design, physical layout implementation, system-level hardware with FPGA firmware design, and testing of a camera-on-a-chip with a novel high-speed CMOS image sensor (CIS) architecture developed for a mega-pixel array. The novel features of the design include an innovative quadruple column-parallel readout (QCPRO) scheme with rolling shutter that increases pixel rate, its ability to program the frame rate and to tolerate Total Ionizing Dose effects (TID). Two versions of the architecture, a small (128 x 1,024 pixels) and large (768 x 1,024 pixels) version were designed and fabricated with a custom layout that does not include …

On The Human Factors Impact Of Polyglot Programming On Programmer Productivity, Phillip Merlin Uesbeck

UNLV Theses, Dissertations, Professional Papers, and Capstones

Polyglot programming is a common practice in modern software development. This practice is often considered useful to create software by allowing developers to use whichever language they consider most well suited for the different parts of their software. Despite this ubiquity of polyglot programming there is no empirical research into how this practice affects software developers and their productivity. In this dissertation, after reviewing the state of the art in programming language and linguistic research pertaining to the topic, this matter is investigated by way of two empirical studies with 109 and 171 participants solving programming tasks. Based on the …

Pressure Driven Electronic Band Gap Engineering In Tin(Iv)-O,N Compounds, Daniel Thomas Sneed

UNLV Theses, Dissertations, Professional Papers, and Capstones

The intrinsic link between long-range order, coordination geometry, and the electronic properties of a system must be understood in order to tailor function-specific materials. Although material properties are typically tailored using chemical dopants, such methods can cause irreversible changes to the structure, limiting the range of functionality. The application of high pressure may provide an alternative “clean” method to tune the electronic properties of semiconducting materials by tailoring their defect density and structure.

We have explored a number of optoelectronic relevant materials with promising characteristics, specifically Sn-(O,N) compounds which have been predicted to undergo pressure-mediated opening of their optical band …

Evaluation Of Titanosilicate Materials For The Sorption Of Cesium And Strontium From High Level Wastes, Matheus Tolentino Lauar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Treatment of high-level waste (HLW) stored in the U.S. Department of Energy (U.S. DOE) sites of Hanford and Savannah River involves the separation of radioactive cesium (137Cs) and strontium (90Sr). Challenges in treating the liquid HLW includes high alkalinity or acidity, and high salt content, many orders of magnitude above Cs and Sr concentrations. Ion exchange is the preferred process for removing these compounds, due to the availability of selective media and large volume-processing capacity by column operations. The crystalline silicotitanate (Na2Ti2O3SiO4·2H2O), i.e. CST, which structure is analog to the mineral sitinakite, is considered the reference material for this application. …

Cell Velocity Is Asymptotically Independent Of Force: A Differential Equation Model With Random Switching., J. C. Dallon, Emily J. Evans, Christopher P. Grant, William V. Smith

Faculty Publications

Numerical simulations suggest that average velocity of a biological cell depends largely on attachment dynamics and less on the forces exerted by the cell. We determine the relationship between two models of cell motion, one based on finite spring constants modeling attachment properties (a randomly switched differential equation) and a limiting case (a centroid model-a generalized random walk) where spring constants are infinite. We prove the main result of this paper, the Expected Velocity Relationship theorem. This result shows that the expected value of the difference between cell locations in the differential equation model at the initial time and at …

A Noncanonical Function Of The Telomerase Rna Component In Human Embryonic Stem Cells, Kirsten Ann Brenner

Arts & Sciences Graduate Student Theses and Dissertations

Telomeres are stretches of TTAGGG nucleotide repeats located at the ends of linear chromosomes that shorten with progressive cell division and prevent genomic instability at the cost of limiting a cell’s capacity to proliferate. This limitation can be overcome by telomerase, a ribonucleoprotein complex that elongates telomeres via reverse-transcription of the template telomerase RNA component (TERC). Recent studies have reported potential functions of TERC outside of its role in telomere maintenance. These noncanonical functions of TERC are however poorly defined, and the molecular mechanisms and biological relevance behind such functions remain elusive. Here, we generated conditional TERC knock-out human embryonic …

Activation And Regulation Of The Alkbh3-Ascc Alkylation Repair Pathway, Josh Brickner

Arts & Sciences Graduate Student Theses and Dissertations

DNA repair is essential to prevent the cytotoxic or mutagenic effects of various types of DNA lesions. These lesions are sensed by distinct pathways to recruit repair factors specific to type of damage. In particular, the ALKBH family of proteins recognizes and repairs specific alkylated lesions, including 1-methyladenine (m1A) and 3-methylcytosine (m3C). A major outstanding question in the field is how the AlkB homologue ALKBH3 and its associated protein partners are recruited to sites of alkylation damage and how this repair activity is regulated. Understanding the upstream signaling events that mediate recognition and repair of DNA alkylation damage is particularly …

Young Children’S Knowledge About The Role Of Print In Reading, Molly Farry-Thorn

Arts & Sciences Graduate Student Theses and Dissertations

Children begin to learn about the print in books and the role it plays in reading well before the onset of formal literacy instruction. Young children’s knowledge about precisely what readers are reading when they read books and who is able to read books has been studied primarily through interviews, but conclusions from this research are limited by methodological concerns. Three experiments examined whether pre-readers understand what part of a book is read and whether they distinguish between the skill of reading and the activity of reading. Although pre-readers were typically able to locate the print in a book, they …

Transcriptional Regulation Of Adipose Tissue Development By Pexrap And Med19, John Dean

Arts & Sciences Graduate Student Theses and Dissertations

Targeting adipose tissue function to decrease adiposity and improve insulin sensitivity could treat obesity and diabetes. How the nuclear receptor PPARγ regulates the development of two functionally distinct types of adipose tissue, brown and white fat (BAT and WAT), as well as the browning of white fat, remains unclear. Our previous studies suggest that PexRAP, a peroxisomal lipid synthetic enzyme, regulates PPARγ signaling and white adipogenesis.Here, we show that PexRAP is an inhibitor of brown adipocyte gene expression. PexRAP inactivation promoted adipocyte browning, increased energy expenditure, and decreased adiposity. Identification of PexRAP-interacting proteins suggests that PexRAP function extends beyond its …

T Cell Immunity In Pancreatic Cancer Is Undermined By Dendritic Cell Dysfunction, Samarth Hegde

Arts & Sciences Graduate Student Theses and Dissertations

Pancreatic cancer carries a dismal prognosis, and desperately needs viable therapeutic interventions beyond chemo-radiation. T cell-dependent immunotherapies have shown great promise in several tumor types, but have not been effective for the vast majority of pancreatic cancer patients. This is, in part, due to our limited understanding of how antigenicity of pancreatic lesions is recognized, and how adaptive immunity is overcome in this disease. We sought to study tumor-immune interactions and identify mechanisms for this immune-failure using several spontaneous and unperturbed mouse models of pancreatic adenocarcinoma. We found that early pancreatic lesions fail to elicit tumor-limiting CD4+ TH1 and CD8+ …

Genomic Contributors To Individual Differences In Reward-Related Neural Activity, Lindsay Jane Michalski

Arts & Sciences Graduate Student Theses and Dissertations

Aberrant reward-related behavior, including impulsive and risk-taking behaviors, is a common feature of externalizing psychopathology (e.g., attention deficit hyperactivity disorder, antisocial personality disorder, and substance-use disorders). Through imaging studies, these behaviors have been linked to dysregulated reactivity within a diffuse reward-related corticostriatal neural network, including the striatum, frontal regions (namely orbital, ventromedial, and dorsolateral cortices), the insula, and the hippocampus. Because variability in risk-taking behavior and related psychopathology is moderately-to-largely heritable (i.e., with estimates ranging from 40 – 80%), a genetically-informed approach is well-positioned to provide valuable insight into the etiology of reward-related neural and behavioral phenotypes that characterize externalizing …

Elucidating Enhancer Function In Epidermal Development And Filaggrin Loss-Of-Function Variants In African American Atopic Dermatitis, Mary Elizabeth Mathyer

Arts & Sciences Graduate Student Theses and Dissertations

The epidermis is the outermost tissue of the skin and provides the body’s first line of defense against external assaults. The epidermis is primarily composed of keratinocytes that terminally differentiate and rise apically toward the surface to form the semipermeable barrier of the skin. A hallmark of keratinocyte terminal differentiation is the expression of genes from the Epidermal Differentiation Complex (EDC) locus. Many of the EDC protein products contribute to the structural integrity of the skin barrier, evidenced by several gene knockouts such as loricrin, and even genetic variation within gene coding sequences, that modulate the integrity of the skin …

The Transcription Factor Bhlhe40 Regulates Tissue-Resident Macrophages And Type 2 Immunity, Nicholas N. Jarjour

Arts & Sciences Graduate Student Theses and Dissertations

Transcriptional control of gene expression is essential for life, tailoring protein production to development and environment to maintain organismal homeostasis. A limited set of proteins termed transcription factors are critical to this process. As our understanding of these central regulators has improved, new aspects of cell and organismal biology have been revealed. Herein, we demonstrate the importance of the transcription factor Bhlhe40 to tissue-resident macrophages, T helper type 2 cells, and type 2 immune responses, revealing novel transcriptional control of macrophages and unexpected cytokine regulation of helminth infection. We find that Bhlhe40 is cell-intrinsically required for normal proliferation of large …

Devising A Scalable Synthesis To Probe The G-Protein Cell Receptor Signaling Pathway, Matthew Robert Medcalf

Arts & Sciences Graduate Student Theses and Dissertations

The G-protein coupled cell receptor signaling pathway is amongst the largest and most diverse class of cell-surface receptors in the body. Nearly 800 different genes encode for these cell membrane receptors which are responsible for mediating a variety of hormones, neurotransmitters, and sensory stimuli through the activation of intracellular G proteins. To date, roughly 34% of pharmaceuticals on the market target GPCR’s, but despite this fact, there are still many difficulties associated with targeting this family of receptors. The vast number of GPCR’s, disease states resulting from a dysregulation of multiple GPCR signaling pathways, and difficulties crystalizing and purifying the …

Phylogenetic And Genomic Characterization Of The Host-Pathogen Arms Race Between Bacterial Pathogens And Gossypium Hirsutum, Anne Zimmerman Phillips

Arts & Sciences Graduate Student Theses and Dissertations

Hosts and pathogens are eternally intertwined in an evolutionary arms race. When a pathogen causes a disease outbreak, scientists must identify resistance strategies that can durably tilt the arms race in favor of the host. This requires a deep understanding of both the genetic and environmental contexts in which the outbreak occurs. In this thesis I investigate the bacterial pathogens Xanthomonas citri pv. malvacearum (Xcm) and Pseudomonas syringae that caused disease outbreaks on Gossypium hirsutum from 2011-2017. I use pathogen genomics and host transcriptomics to develop hypotheses for how these pathogens emerged and how they cause disease. Phylogenetics and virulence …

Physiologic And Pathologic Profiling Of Clonal Variations, Wing Hing Wong

Arts & Sciences Graduate Student Theses and Dissertations

This thesis sought to provide a better understanding of clonality in various malignant and non-malignant settings using a variety of genomic analytical tools. Clonality is pre-defined as the presence of a mixed population of cells in which each sub-population has distinct somatic mutation profile. It is a common feature in cancers where subpopulations of cells arise as a result of independent, yet continual acquisition of somatic mutations. The clonal architecture of cancers can be used as a diagnostic and prognostic biomarker as well as to monitor disease progression or resolution. Besides cancer, clonal variability and expansion is also implicated in …

Crip Time In Fin-De-Siècle Spain: Disability, Degeneration, And Eugenics, Erika Rodriguez

Arts & Sciences Graduate Student Theses and Dissertations

A period of intense nation-building, the late nineteenth century was marked by the search for medical and legal solutions to the increasing number of bodies that did not align with culturally constructed expectations of productivity and reproduction in Spanish modernity. Authors of this time used representations of disability to engage in urgent political questions about population control and the rights of individuals in the face of increasing medical intervention. In carrying out this analysis, I raise the question of how representations of disability created a space to reconfigure the social values that determined what lives matter. Focusing on canonical realist …

Generation And Utilization Of Diverse Memory B Cells After Flavivirus Challenges, Rachel Wong

Arts & Sciences Graduate Student Theses and Dissertations

Over the course of an effective immune response to an infection, two distinct B cell populations are generated to provide protection against reinfection, long-lived plasma cells (LLPCs) and memory B cells (MBCs). LLPCs and MBCs originate from germinal center (GC) B cells that have undergone B cell receptor (BCR) affinity maturation through iterative rounds of somatic hypermutation, proliferation, and selection. Thus, LLPCs and MBCs can bind to their antigen with higher affinity than their naïve B cell precursors. LLPCs constitutively secrete antibodies and can provide sterilizing immunity that pre-exists subsequent infections. MBCs, on the other hand, are quiescent and provide …

Investigating Biological Mechanisms Of Radiation Resistance In Advanced Stage Cervical Cancer, Fiona Ruiz

Arts & Sciences Graduate Student Theses and Dissertations

The current standard of care treatment for locally advanced cervical cancer is curative intent pelvic radiation with concurrently administered platinum chemotherapy (CRT). This treatment strategy is effective for many patients, but 33-50% of patients treated with CRT develop disease recurrence. Metastatic and recurrent cervical cancer is an incurable condition, and many of the currently available treatments are associated with significant morbidity and mortality. Identifying these patients upfront is a challenge that clinicians face when developing treatment strategies. Previous studies used to catalog the genomic and transcriptomic landscape of cervical cancer lacked high quality corresponding clinical follow up data for patients, …

An Evolving Epigenome That Determines Tissue And Cell Specificity, Renee Louise Sears

Arts & Sciences Graduate Student Theses and Dissertations

Understanding the mechanisms driving phenotypic variation is a major goal of biology that unifies classical genetics with the emerging fields of genomics and epigenomics. Human and mouse share over 90% of genes and global tissue-specific patterns of expression are maintained between the species. Thus, it is hypothesized that gene expression is influenced through distinctive regulation among species in order to account for the unmistakable phenotypic divergence. DNA methylation, histone modifications, open chromatin patterns, transcription factor binding, and other epigenetic factors are all associated with shaping, maintaining, and repressing regulatory regions which in turn coordinate gene expression. It is vital to …

Coulombic And Non-Coulombic Effects Of Single And Overlapping Electric Double Layers With Surface Charge Regulation, Raviteja Vangara

Chemical and Biological Engineering ETDs

The physical origin of charged interfaces involving electrolyte solutions is in the thermodynamic equilibrium between the surface reactive groups and certain dissolved ionic species in the bulk. This equilibrium is very strongly dependent on the precise local density of these species, also known as potential determining ions in the solution. The latter, however, is determined by the overall solution structure, which is dominated by the large number of solvent molecules relative to all solutes. Hence, the solvent contribution to the molecular structure is a crucial factor that determines the properties of electric double layers. Models that explicitly account for the …

Atrial Fibrillation Detection From Smartwatch Based Photoplethysmography Signals, Syed Khairul Bashar

Master's Theses

Detection of atrial fibrillation (AF) from a wrist watch photoplethysmography (PPG) signal is important because the wrist watch form factor enables long term continuous monitoring of arrhythmia in an easy and non-invasive manner. We have developed a novel method not only to detect AF from a smart wrist watch PPG signal, but also to determine whether the recorded PPG signal is corrupted by motion artifacts or not. In order to detect the motion and noise artifacts from PPG signal, we have used both the accelerometer signal and variable frequency complex demodulation based time-frequency analysis of the PPG signal. After the …