Digital Commons Network^™

Stereotactic Radiosurgery Implementation At Utah Valley Hospital, Ryan Sharp

UNLV Theses, Dissertations, Professional Papers, and Capstones

Utah Valley Hospital (UVH) implemented a stereotactic radiosurgery (SRS) program as an additional line of service. SRS as defined by the American College of Radiology is radiation therapy delivered via stereotactic guidance with approximately 1 mm targeting accuracy to intracranial targets in 1-5 fractions. Effectively implementing the SRS program at UVH requires the adoption and implementation of hardware and software technologies, a review of the clinical workflow with appropriate quality assurance tests, and the assessment of additional technologies that will further enhance the capabilities of the program. The scope of this work is to include a comprehensive writeup of the …

Gen-Foam Multiphysics Model Development For Molten Salt Reactors, Jeffrey Stewart

UNLV Theses, Dissertations, Professional Papers, and Capstones

In thermal neutron spectrum Molten Salt Reactors (MSR), a graphite moderator contributes a positive reactivity value to the overall temperature reactivity coefficient of the core. When irradiated in the core, graphite undergoes dimensional changes which depend on the neutron spectrum. The graphite lifespan is a limiting parameter in MSR designs; it correlates strongly with the graphite’s dimensional changes. Multi-physics modeling is necessary to evaluate the graphite thermal and mechanical responses to the MSR core conditions. To assess graphite dimensional changes associated with irradiation, a computational model was developed upon the foundation of the multi-physics solver, GeN-Foam. Irradiated graphite dimensional change …

Front-End Cmos Transimpedance Amplifiers On A Silicon Photomultiplier Resistant To Fast Neutron Fluence, Mario Valles Montenegro

UNLV Theses, Dissertations, Professional Papers, and Capstones

Radiation hard electronics are indispensable in providing reliable diagnostics in fast radiation detection, which are necessary for new fundamental science research. In the case of radiation detection, transimpedance amplifiers are needed to magnify low photodetector signals to readable levels reliably. This thesis investigates a way to design a transimpedance CMOS-front-end transimpedance amplifier (TIA) as a first stage front-end amplifier. The TIA is to be mounted on silicon photomultiplier (SiPM), as a photodetector in fast neutron scintillation experiments capable of sustaining up to 10^15 n/cm of fast neutrons in the range of 0.1 to 20 MeV. The proposed TIA was designed …

Respiratory And Perceptual Responses To High Intensity Interval Exercise In Obese Adults, Nicholas Andrew Ross

UNLV Theses, Dissertations, Professional Papers, and Capstones

Purpose: Obese adults experience low lung volume breathing at rest and during exercise, which provokes ventilatory constraints and dyspnea on exertion. High-intensity interval exercise (HIIE) has emerged as an alternative to continuous exercise (CE); however, the effects of HIIE on lung volumes, ventilatory constraints and dyspnea on exertion have not been studied in obese adults and thus tolerability of HIIE remains unknown. Therefore, the purpose of this study was to examine the differences in respiratory and perceptual responses during HIIE versus CE in obese adults when compared with nonobese adults. Methodology: Ten healthy, nonobese (24.1 ± 6.2 yr., BMI: 23 …

Tales Of Thriving: Identifying The Underpinnings Of Women's Success In Stem Careers, Sarah E. Thoman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Women remain underrepresented in U.S. science, technology, engineering, and math (STEM) fields. Prior research enumerates many challenges that women experience in STEM and suggests interventions that enhance women’s exposure to STEM, technical acumen in STEM, or offer STEM community. Identifying what enables women to thrive in STEM is a novel approach to extending these efforts using a strengths-based approach. I thus conducted a case study focused on understanding the experiences of successful women in the STEM workforce. Findings revealed three core characteristics to women’s STEM success: synergizing self and science, science career advancement and mastery, and being a STEM change …

Dark Tetrad Responses To Moral Dilemmas, Kayli Wrenn

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Dark Tetrad consists of four socially malevolent personality traits: psychopathy, sadism, narcissism, and Machiavellianism. The current study assessed the relationships among each dimension of the Dark Tetrad and moral decision making using sacrificial moral dilemma vignettes. Participants (n = 212 undergraduates) completed two measures of each of the four Dark Tetrad constructs then read a series of 16 sacrificial moral dilemma vignettes. These dilemmas manipulated whether the participant would personally perform the sacrifice and described either the disgusting or sad emotional consequences of the sacrifice. After each vignette, participants rated the moral rightness/wrongness, moral permissibility, and behavioral intention to …

Public-Private Partnership Contract Framework Development And Project Performance Analysis Compared To Design-Build In The Us Highway Projects, Medya Fathi

UNLV Theses, Dissertations, Professional Papers, and Capstones

Construction projects can be delivered through various approaches; nevertheless, all practitioners and involved parties have a mutual goal, which is completing the project within the original scope, defined budget, and schedule. Reviewing the literature on public-private partnership (PPP), many efforts have been made covering different research areas, including policies, risks, roles and responsibilities, and finance. However, a study involving the development of a framework for PPP contracts, and quantitative assessment of project performance associated with PPP highway projects in the US is lacking. Therefore, this research fills such a noticeable gap in the body of knowledge on the PPP delivery …

Detection Of Snps Associated With Bone Loss Rate By Using Machine Learning Approaches, Avinash Yaganapu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Osteoporosis is one of the most common diseases seen in postmenopausal women, it decreases the bone density and quality, and later causes bone loss. Generally, bone loss occurs when bone losses its content and become porous: a sponge like substance. In most Genome Wide Association Studies (GWAS), researchers perform experiments with genomic data that contains some millions of numbers of single nucleotide polymorphisms (SNPs) and checks their association with the trait or disease. In this thesis, we performed two separate analyses with 2207 (of bone loss and bone gain) and 645 (of bone loss) instances separately. For predicting the SNPs …

Infiltration Into Water-Repellent Sand: The Role Of Sorptivity, Rose Marie Shillito

UNLV Theses, Dissertations, Professional Papers, and Capstones

Soil water repellency (SWR) is believed to contribute to the increased potential for post-fire runoff and erosion. Currently, no quantitative method exists to account for SWR in physically-based runoff models. A physically-based model incorporating SWR (through the contact angle) in the infiltration parameter, sorptivity, was developed. The model was tested and verified with controlled laboratory tests on a fully characterized sand treated to create various degrees of SWR. The ability to create the wetting water characteristic curve for untreated and treated sand, appropriate for the infiltration process, was presented. Additionally, the ability to measure sorptivity with widely used infiltration tests …

Patients Enabled, Engaged, And Empowered: Implementation Of A Mobile Patient Engagement Technology, Jud Simonds

UNLV Theses, Dissertations, Professional Papers, and Capstones

Patient engagement technologies present an opportunity to enhance the patient experience by providing patient access to information throughout the entire, often complex, continuum of care. Growing evidence indicates that a lack of patient engagement is a significant contributor to preventable deaths. In contrast, engaging patients in their healthcare can positively affect patient outcomes and the overall patient experience. Unfortunately, traditional patient care models involve face to face patient-provider interactions, thereby limiting reach and impact. Exploring new roles for information technology (IT) within healthcare can contribute to addressing barriers encountered in more traditional healthcare models. Innovative IT solutions can assist patients …

The Las Vegas Metropolitan Revolution: A Case Study Of Public Policy In The Nevada Legislature, Caitlin J. Saladino

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this qualitative case study is to explain the dynamics of metropolitan policymaking in Las Vegas, Nevada. This study utilizes advocacy coalition framework to show how underlying beliefs among policy actors, and within the coalitions they form, impact decisions made at the level of the Nevada Legislature. As the newest metropolitan region to emerge among the top 30 metros in the United States, a case study exploring Las Vegas offers a unique contribution to existing literature in public policy and urban affairs. In the wake of economic downturn in the Great Recession and the adoption of a new …

High Salinity, High Concentration Perchlorate Reduction In The Presence Of Hexavalent Chromium, Nitrate, And Chlorate, Nicole Martin

UNLV Theses, Dissertations, Professional Papers, and Capstones

Perchlorate is a chemically stable anion which was used as an oxidizer in rocket propellant and explosives throughout the 1950’s and 1960’s. While natural sources of perchlorate exist, perchlorate in the environment is primarily a result of contamination from anthropogenic processes. Perchlorate contamination has now been identified in at least 45 states and is hazard to human health due to perchlorate’s ability to interfere with uptake of iodine in the thyroid gland. One of the most common and cost effective treatment methods for perchlorate remediation is biological reduction—utilizing bacteria to enzymatically reduce perchlorate into chloride and oxygen.

The purpose of …

3d Parametric Hand To Improve Prosthetic Hand Functionality, Maria C. Gerardi

UNLV Theses, Dissertations, Professional Papers, and Capstones

The use of prosthetics can significantly enhance an individual’s standard of living, not only offering functional advantages but psychological advantages as well. Unfortunately for children with upper limb reduction, options are limited and rejection rates are high due to a multitude of reasons including discomfort and poor functionality. This study proposes a new parametric 3D design model (Parametric Hand) with an adjustable thumb that can be easily manipulated to the uniqueness of an individual. The Parametric Hand was evaluated, both qualitatively and quantitatively, against the Flexy-Hand 2, a commonly used prosthetic hand. The results showed insignificant differences in all testing …

An Evaluation Of Bank Storage At Lake Mead Reservoir In The Southwest United States, Jon Woodrow Wilson

UNLV Theses, Dissertations, Professional Papers, and Capstones

A water balance model is employed at Lake Mead to monitor and verify changing hydrology that affects total volume at the reservoir. Bank storage, which is defined as the volume of water captured in permeable lithologic layers subject to changes induced by contact and proximity to an open waterbody, is one component that is updated regularly and is based upon data and methods that were developed in the 1960’s from observations made within the first 30 years of the reservoir's maturation. Since this period, the reservoir has undergone further development and a current understanding of additional hydrologic affects to bank …

The Dynamic Control Platform: Reinventing The Wheel, One Leg At A Time, Angel Javier Solis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Upright bipedal walking is a complex balance of forces and actions that is almost taken for granted. How this system is modeled, how it affects a prosthesis, and how it can be implemented in the real world are topics that the proposed Dynamic Control Platform aims to address.

The Dynamic Control Platform (DCP) is a bipedal robot designed to test bio-inspired control algorithms with the aim to smooth out the walking experience for prosthetic legs. The main control paradigm that the DCP centers on the principle of orthogonal constraint, which aims to enforce a perpendicular relationship between the center of …

Coping On The Fly: School Psychologists' Perceptions Of Cultural Competence, Jennifer Wynn

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this qualitative ethnographic study is to explore how school psychologists demonstrate multicultural competence (MC) when testing students for K-12 special education. As the population of the United States (US) becomes increasingly diverse, mental health professionals are encouraged to become culturally competent. Cultural competence is the ability to work with culturally and linguistically diverse populations; and being aware of stereotypes, biases and microaggressions. Cultural competence is taught within some psychology preparation programs; however, courses are often limited. Although cross-cultural competencies have been explored in clinical and counseling psychology, they have yet to be explored in the field of …

Reflections Of An Early Literacy Professional Learning Community: An Interactional Ethnographic Case Study Of Transforming Pedagogy Through Reflective Practice, Carly Waters

UNLV Theses, Dissertations, Professional Papers, and Capstones

Teachers have historically been faced with extrinsic factors, such as federal, state, and local mandates, that leave them feeling disempowered (Slattery, 2006; Spring 2018). In response to low reading proficiency, many states have adopted Read by Grade Three laws, some of which require or make optional retention of students that are not reading proficiently by the end of third grade. Laws such as these, though well-intentioned, provide another external force that leave teachers feeling stressed and chained to practices they are told to implement. Effective professional development that targets both strong early literacy pedagogy and the empowerment of teachers may …

Organizational Symbolism And Employee Immersion, A Mixed Methods Investigation Of Organizational Socialization Efficacy In The Hotel Industry, Jeffrey Michael Yedlin

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study delves into the theory of organizational socialization through a mixed methods exploratory explanatory design examining organizational symbolism and social capital to identify strategies to reduce new hire turnover in hospitality. Constructs within the study include role clarity, training, organizational and coworker support as well as future prospects. New literature was studied for developing theory. Seminal work on socialization by Van Maanen and Schein (1979), Feldman and March (1981), Jones (1986), and Taormina (1997), perceived organizational support from Eisenberger et al., (1986), self-efficacy from Bandura (1977), and organizational symbolism by Dandridge & Mitroff (1980) and Van Buskirk (1991) were …

Examining Grit With Middle Schoolers In Diverse General Education Classrooms – Validating The Grit Scale, Cristina Liliana Reding

UNLV Theses, Dissertations, Professional Papers, and Capstones

Educators and researchers are still attempting to narrow the achievement gap for students in diverse needs general education classrooms. In this quest, non-cognitive skills are being researched for their potential to influence behavioral changes and to increase the academic success of diverse needs students. Grit, a newly defined non-cognitive skill, is defined as perseverance and passion for long term goals. This construct has been explored in a variety of settings but not in diverse general education classrooms, with participants from culturally, linguistically and ability diverse groups. The validity of instruments is paramount for successful studies, and current scales measuring non-cognitive …

Mojave Desert Ecosystem Recovery: Potency Of Biotic And Abiotic Restoration Methods In Low Elevation Plant Communities, Mary Amanda Balogh

UNLV Theses, Dissertations, Professional Papers, and Capstones

The historic and current state of land in the Mojave Desert, including land managed by the National Park Service with fundamental goals of natural resource conservation and preservation, been severely degraded by a variety of anthropogenic disturbances. Due to increasingly sporadic and unpredictable precipitation patterns, land managers struggle to implement restoration projects with high success rates and are resource-limited for post-treatment monitoring. In this study, I examined success rates of biotic (outplanting, seeding) and abiotic (soil manipulation, vertical mulch) restoration treatments on various disturbance types in the creosote-bursage (Larrea tridentata-Ambrosia dumosa), blackbrush (Coleogyne ramosissima), and Joshua tree woodland (Yucca brevifolia) …

A Retrospective Survey Of Exercise Habits In Low-Income Female Senior Citizens, Kelly L. Bumgarner

UNLV Theses, Dissertations, Professional Papers, and Capstones

American adults spend at least 50% of their time sedentary with the most inactive demographic being low-income women over 60. This is detrimental because routine physical activity benefits for senior women include balancing hormones, maintaining bone mineral density, and decreasing the risk of breast cancer. Statements like “good exercise habits begin during youth; children should play sports to establish healthy habits they’ll continue throughout their lives” are common, but not clearly supported by literature. Objective: The purpose of this retrospective, cross-sectional study was to identify whether physical activity/exercise habits during youth and young adulthood predict old age physical activity/exercise habits …

Benson’S Relaxation Response: Psychological And Physiological Responses Among Patients With Copd, Crista Reaves

UNLV Theses, Dissertations, Professional Papers, and Capstones

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the United States. In patients with COPD, distress is significantly prevalent and can have adverse psychological and physiological effects. Considering the increased rate of COPD, a mind-body intervention focusing on the reduction of both psychological and physiological responses such as anxiety, elevated blood pressure (BP), heart rate (HR), dyspnea, and respiratory rate must be integrated into the patient’s plan of care. The relaxation response (RR) is a term coined by Dr. Herbert Benson in the 1970s describing the body’s ability to counter the fight-or-flight response to decrease …

Performance Modeling Of Supercritical Carbon Dioxide Zigzag-Channel Printed Circuit Heat Exchangers, Katrine Birgitte Bennett

UNLV Theses, Dissertations, Professional Papers, and Capstones

Supercritical carbon dioxide (sCO2) is currently being studied as the working fluid in power producing Brayton cycles due to its excellent physical and thermodynamic properties, especially near the critical point. Printed circuit heat exchangers (PCHEs) are being considered for use as condensers and recuperators for this purpose due to their high strength and compact designs. Many experimental and numerical studies are being conducted to characterize and optimize sCO2 PCHE operation and develop correlations to describe their thermal-hydraulic performance. Additionally, a few experimental and numerical structural assessments of these PCHEs have been conducted, but all have been somewhat limited due to …

Landscape Scale: Inter- And Intraspecific Variation In Plant Interactions Along A Stress Gradient In The Sheep Range Of Nevada, Jordan Dowell

UNLV Theses, Dissertations, Professional Papers, and Capstones

Impending threats to shrubland ecosystems, posed by climate change, necessitate niche modeling efforts to project vegetation range shifts. However, efforts often remain unguided by individual-scale interspecific plant interactions. The stress gradient hypothesis posits that facilitation should increase in areas of high abiotic stress, only if the individuals are able to ameliorate the surrounding area via functional traits. The Sheep Range of Nevada was used to assess the role of functional traits as predictors of plant association. Larrea tridentata, Coleogyne ramosissima, and Artemisia nova were selected as shrubs with variable life history strategies and ranges in order to identify general patterns …

Trade-Offs Between Survival And Reproduction In Starvation-Selected Drosophila Melanogaster, Tammara Beeghly

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evolutionary outcomes are demonstrated by traits that affect an organism’s schedule of reproduction and survival. These life history traits are reflected in an organism’s physiology, development and behavior. Environmental changes, such as availability of nutritional resources, can profoundly affect evolutionary outcomes of individuals and populations. When shortages arise, there will be trade-offs in the allocation of resources, where one trait prevails at the expense of another.

In the laboratory, we can mimic conditions in nature and study the specific effects of the conditions that we re-create. In our case, over 100 generations of Drosophila melanogaster have been selected for starvation …

Uncovering The Women In Ocean’S Eight: Understanding The Trends Of The Women’S Movement With The Portrayals Of Women In Film, Elyssa Michelle Day

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study seeks for a better understanding of the correlations between major milestones in the women’s movement and how that is reflected onto the silver screen. With the rise of sexual assault allegations against prominent figures in Hollywood, and the growth of the #MeToo movement, we in turn are beginning to see an influx of films being released, and older films being rebooted, with an all-female led cast. One of those all-female film reboots is Ocean’s Eight, a film coming from a male-dominated trilogy and genre. Because of this correlation, the question of whether the narratives within Ocean’s Eight reinforce …

Meal Duration: Implications For Restaurant Revenue Management, Dale F. Billings

UNLV Theses, Dissertations, Professional Papers, and Capstones

A comprehensive revenue management strategy addressing space, product, price and time, has been shown to increase profits within the hospitality sector. While the literature shows that the restaurant industry has frequently addressed space, product, and price when looking at financial strategy, the effect of the variable of time on revenue generation has not been adequately studied. Restaurants shy away from the practice of using time as a commodity, particularly regarding meal duration, due to fears of reducing customer satisfaction.

This project explores the use of time as a commodity in restaurant revenue management. In particular, it examines consumers’ feelings about …

Zirconium Tetrachloride, Fundamental Chemistry And Nuclear Fuel Cycle, Rosendo Borjas Nevarez

UNLV Theses, Dissertations, Professional Papers, and Capstones

Zirconium alloys are used in the United States as cladding materials in nuclear reactors. The purification of Zr is of relevance due to the large amount of spent nuclear fuel produced every year (2,000 metric tons per year and rising), of which 25% corresponds to radioactive zirconium cladding. Through the recovery and reuse of Zr, estimated savings of $40 million per year are estimated due to the high cost of hafnium-free nuclear grade zirconium, and also due to the minimization of nuclear waste disposal requirements.

Several chemical approaches have been proposed for the recovery and purification of Zr. Historically, a …

Arbitrary High Order Finite Difference Methods With Applications To Wave Propagation Modeled By Maxwell's Equations, Min Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation investigates two different mathematical models based on the time-domain Maxwell's equations: the Drude model for metamaterials and an equivalent Berenger's perfectly matched layer (PML) model. We develop both an explicit high order finite difference scheme and a compact implicit scheme to solve both models. We develop a systematic technique to prove stability and error estimate for both schemes. Extensive numerical results supporting our analysis are presented. To our best knowledge, our convergence theory and stability results are novel and provide the first error estimate for the high-order finite difference methods for Maxwell's equations.

Evaluating Parents Sociodemographic Factors And Childhood Vaccine Decisions, Mehret Girmay

UNLV Theses, Dissertations, Professional Papers, and Capstones

Vaccination is considered one of the most successful public health achievements of the 20th century. However, with increasing vaccine skepticism emerging over the past decades, there is a threat to the ongoing sustainment of vaccine coverage within all US communities. This study evaluated and compared parents’ sociodemographic factors associated with childhood vaccine decisions. This study is a secondary analysis of 893 parents/guardians, age 18-55 years with child(ren) < 7 years living in the U.S.

Predictive analysis was conducted using multinomial logistic regression modeling was used to examine vaccine decisions (accept, hesitant, and refuse) in relation to parents’ sociodemographic factors. Overall, (66.6%) of parents accepted recommended vaccines, while …