Digital Commons Network^™

An Avalanche Transistor-Based Pulse Generator Design For Infrared Laser Applications, Abraham Lopez

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis details the design and results of a circuit intended for infrared laser applications, specifically for transcranial infrared light simulation (TILS) experiments and for use as a range finder. The circuit itself is comprised of a transistor, high voltage power supply, laser diode, capacitor, resistor, diode, and low voltage pulse. The design of a range finder is also developed. The range finder design is the same as the circuit developed for TILs with the addition of a few more components for receiving the returned light pulse such as a photodiode, op-amp, and comparator. The techniques used for a successful …

Initial Development And Psychometric Evaluation Of The Mental Health Optimization Checklist (Mhoc), Raymond E. López

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background: The Mental Health Optimization Checklist (MHOC) is a proposed measure which utilizes the theory of optimization science to improve mental health outcomes. Psychopathology is typically viewed dichotomously (i.e., does or does not have a disorder) or through cut-off criterion (i.e., 4 out of 5 symptoms, total scores), whereas optimization views psychopathology on a continuum on which patients can optimize factors impacting their mental health. Optimization theory is important for reducing stigma around mental health treatment and the MHOC offers itself as an informative psycho-diagnostic tool.

Methods: An undergraduate student sample (n = 682) completed the MHOC and the Symptom …

Cellular Heat Responses Of Desert Mammals Promote Survival In Extreme Conditions, Janessa Montenegro

UNLV Theses, Dissertations, Professional Papers, and Capstones

Increasing temperatures with the potential for heat stress is among the future threats facing many mammals. Cellular mechanisms to maintain homeostasis in the face of heat stress likely differ across species based on naturally tolerated intracellular variability. In some mammals, the homeostatic set point in cells has a narrow range. Other species tolerate more varied intracellular conditions, including in temperature. Heat stress responses of cultured dermal fibroblasts from several mammals were compared to detect cell proliferation and cellular death (chapter 2). Cells from heat- tolerant species (13-lined ground squirrel, dromedary camel, round-tailed ground squirrel, and white-tailed antelope squirrel) were compared …

Magmatic Processes Leading To Compositional Diversity In The Mars Crust, Amanda Marie Ostwald

UNLV Theses, Dissertations, Professional Papers, and Capstones

The ancient Mars crust can yield insights into planet formation and evolution that Earth cannot. Direct investigation of the martian surface is limited to studies on meteorites and rover-obtained analyses. The nakhlites and chassignites, two classes of martian meteorites, are together the largest suite of martian meteorites derived from a single location on the surface. As such, they present a rare opportunity to study the Mars crust in detail using samples bearing a contextual relationship. Rover studies have found a surprising amount of compositional diversity in surface materials, the formation mechanisms of which are not well-constrained. This dissertation leverages meteorites …

Towards Cfd Investigations Into Particulate Air Pollution Of A Desert Urban Environment, Prosun Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation has explored computational fluid dynamics (CFD) techniques for studying particulate air quality in the Las Vegas urban area. The dissertation is based on three research tasks:

• • High time-resolution fenceline air quality sensing and dispersion modeling for environmental justice-centered source attribution. (Chapter 2)
• • Pollen dispersion and deposition in real-world urban settings: A computational fluid dynamic study. (Chapter 3)
• • Effects of urban canopy parameterizations on modeling pollen dispersion and exposure. (Chapter 4)

In Chapter 2, we investigate the facilitation of low-cost air quality sensors (LCAQS) and CFD technique on exposure assessment of environmental justice (EJ) communities and …

The Psychopathology Circumplex+: A Novel Conceptualization Of Psychopathology And Associated Measure, Edward A. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

Fearless Dominance (FD) and Impulsive Antisociality (IA) are two personality traits often used in the study of psychopathic personality. FD is characterized by a lack of empathy, resilience to stress, and social potency, while IA is marked by impulsivity, selfishness, and manipulativeness. The current trio of studies sought to expand the use of FD and IA to assess psychopathology more generally. Study 1 consisted of a meta-analysis of all the relationships between FD/IA and various forms of psychopathology. Results affirmed that FD and IA each correlate with a variety of different psychological disorders, each to varying degrees of magnitude, but …

Benchmarking And Practical Evaluation Of Machine And Statistical Learning Methods In Credit Scoring: A Method Selection Perspective, Gwen Verbeck

UNLV Theses, Dissertations, Professional Papers, and Capstones

Predictive models are important tools used in all scientific fields. Machine learning (ML) algorithms and statistical models are widely used for decision-making because of their capability to tackle intricate and unique problems. In domains where data are high-dimensional and contain irrelevant and redundant features, ML algorithms are known to have superior performance over traditional (statistical) learning methods. However, researchers and analysts are often faced with a myriad of techniques to choose from, with no clear consensus on which will perform best for their specific task. Considering resource limitations, exhaustive exploration of all available methods is impractical and often fails to …

Offender Reintegration In Nevada: A Longitudinal Study Focusing On Transitional Challenges, Reentry Capital, And Recidivism, Carolyn S. Willis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Offender reintegration (reentry) depends on offender motivation, public policies, community efforts, and resources provided through government and nonprofit sectors. As individuals are released from incarceration and reintegrate into the community, they are often dependent on resources provided by different service providers and the community. The role of the community is crucial as resources are oftentimes not accessible. Lack of employment and housing, mental health issues, substance abuse, and the inability to reestablish personal relationships diminish the prospects of successful reintegration and increase the chances of reincarceration. Reentry capital delivered through community-based programs addresses the transitional issues justice-impacted individuals encounter post-incarceration. …

Polygenic Risk Score Development And Validation For Early Detection And Risk Stratification Of Rheumatoid Arthritis And Osteoarthritis In Postmenopausal Women, Yingke Xu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Around one in four adults worldwide suffer from arthritis. There are more than one hundred different forms of arthritis; the two most common forms of arthritis are rheumatoid arthritis (RA) and osteoarthritis (OA). RA is an autoimmune disease that can cause joint inflammation. Around 1.3 million adults in the US suffer from RA, representing 0.6%–1% of the population. The RA diagnosis in its early stages is difficult since its signs and symptoms are similar to other arthritis. OA is the most common form of arthritis. In the US, around 30.8 million people are affected by this disease. However, OA …

Decision Making Under Uncertainty – Percieved House Edge Or Game Outcome, Haocheng Zhou

UNLV Theses, Dissertations, Professional Papers, and Capstones

Past studies have suggested that decision-making strategies are crucial for players in casino gambling, yet few studies have explored players' preferences for slot machines. This study focused on the impact of jackpot payouts, the perceived house edge, and psychological factors on the decision-making of slot machine players. With regard to Prospect theory, Outcome Prominence Effect, and Construal Level Theory, this study utilized convenience sampling and scenario-based surveys to collect data. A total of 416 experienced slot players participated in the survey. The survey results were examined using Chi-square analysis, Bonferroni correction, and the Wilcoxon Signed-Rank Test. The results showed that …

Survey Of How Irregularities In The Electrical System Of The Human Heart Link To Different Heart Arrhythmias, Jazmine Boloor

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis explores the circuital pathway that a signal takes within the heart throughout a full heartbeat and provides a timing analysis. It then surveys the different pathways that could arise in the electrical system of the heart, and the associated heart diseases linked to the location of each pathway. Common heart arrhythmias such as atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia, atrial flutter, and atrial fibrillation are surveyed, and their pathways are analyzed. Electrocardiograms are presented to aid in understanding of the timing analysis associated with irregularity in heart function. Finally, this thesis explores an avenue of the heartbeat …

Cultural Mechanism Of Mothers' Perceptions Of Youth Psychopathology, Yen-Ling Chen

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cross-cultural research systematically identifies variations in cultural practices, meanings, and responses across different cultural groups. For example, psychiatric symptoms vary in their salience and degree to which they are reported across cultures. Cultural differences in causal attributions likely lead to differences in an individual’s help-seeking intention. However, there are limitations in previous cross-cultural studies about perceptions of psychopathology, including not measuring impairment level and parental distress, as well as the problematic use of categorical variables as predictors. To overcome limitations in previous work, the current project examined the cultural mechanism of mothers’ perceptions of externalizing and internalizing psychopathology in youth. …

The Relationship Between Psychopathy And Sexism Across Self-Report, Vignette, And Novel Dialogue Tree Tasks, Arianne Fisher

UNLV Theses, Dissertations, Professional Papers, and Capstones

Psychopathy is a personality construct consisting of a number of traits often associated with what many consider to be the “dark side” of personality. Multiple models and associated measurement tools have been created in an attempt to conceptualize psychopathy, but the field has not reached a consensus in its definition of this construct at this time. Across models, psychopathy is associated with a number of negative attitudes and behaviors, including various forms of prejudice. The relationship between psychopathy and one form of prejudice has not been examined, constituting a serious gap in the literature. This form of prejudice is ambivalent …

Principals’ Perceptions Of School Sponsored Field Trips, Melissa Suzanne Giannantonio

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this phenomenological study is to explore the views, attitudes, and ideas that school principals have on school-sponsored field trips. As society continues to change it is increasingly necessary to contemplate the growing significance of field trip facilities’ educational roles and garner “information about the audiences they serve” (Anderson et al., 2015, p. vii). Additionally, the past decade has seen a decline in the number of field trips taken by schools, and in 2020, field trips came to a complete halt due to COVID-19 (Center for Disease Control (CDC), 2020; Mathews, 2014; Mehta, 2008; Plummer, 2014; Reeves & …

Babywearing's Influence On Parent And Infant Heart Rates, Joo-Hee Han

UNLV Theses, Dissertations, Professional Papers, and Capstones

Babywearing is the practice of carrying an infant in a baby carrier close to the body. It provides an environment that allows the bodies of the parent and infant to be close together. The closeness of parent and infant improves the well-being and coregulation of the parent and infant, which could be estimated with heart rate (HR). Few studies have examined mother-infant dyads, but even fewer have examined father-infant dyads. This study examined mother-infant and father-infant dyads, especially for infants with neonatal abstinence syndrome (NAS). The significance of studying babywearing in this vulnerable population is that if babywearing is associated …

Instructional Practices That Foster Argumentative Discourse In Secondary Science Classrooms, Alicia N. Herrera

UNLV Theses, Dissertations, Professional Papers, and Capstones

To remain competitive in an innovative world, American classrooms are promoting careers in science, technology, engineering, and mathematics (STEM) by utilizing the Next Generation Science Standards (NGSS). Students are engaged in inquiry by applying scientific practices like argumentation. However, science teachers are finding it difficult to respond to, as well as deepen students’ argumentative conversations. Therefore, research must uncover what instructional practices (or combinations) are used to overcome classroom obstacles, along with fostering students’ discourse and sensemaking. A teacher research approach was taken to investigate how the researcher, a secondary science teacher herself, effectively combines three under-researched instructional practices for …

Depression, Anxiety, And Estimated Cardiorespiratory Fitness In College Students, Christian Ison

UNLV Theses, Dissertations, Professional Papers, and Capstones

Depression and anxiety disorders are two common mental health conditions worldwide. College students are considered a high-risk population for the development of these conditions. Improved cardiorespiratory fitness (CRF) has been shown to decrease depression and anxiety risk, symptoms, and severity but this relationship and the extent to which improved CRF can reduce these risks has yet to be examined in the college student population. Validated and reliable non-exercise estimated cardiorespiratory fitness (eCRF) algorithms could be used to identify relationships and associations with depression and anxiety severity levels among college students. The purpose of this study was to assess eCRF and …

Examining Athletic Training Educators’ Perceptions Of The Entry-Level Master’S Degree, Elizabeth León Zaragoza

UNLV Theses, Dissertations, Professional Papers, and Capstones

In 2015 the Athletic Training Strategic Alliance made the decision to transition all athletic training programs from undergraduate level degrees to entry-level master’s degrees. This decision stems from efforts to align the athletic training profession with other allied health professions. With this decision came several concerns including the impact that it would have on the diversity within the profession. The decision presented the likelihood of unintended consequences impacting access to athletic training education for students and faculty from minoritized communities. Therefore, the purpose of this study was to examine athletic training educators’ perceptions of the Entry-Level Masters (ELM) degree requirement …

The Effects Of The Diversion Program On Student Resilience, Mandi L. Merrill

UNLV Theses, Dissertations, Professional Papers, and Capstones

The current study examined whether The Diversion Program is associated with an increase in student resilience. Fifty-one students 10- 18 years old participated in this study. Participants completed a resilience measure reflecting the multiple pathways and processes embedded in different contexts. A pretest-posttest design was used to evaluate the effects of the Diversion Program on students' resilience. As predicted, students’ resilience increased significantly from the pretest to the posttest. Results demonstrated the promise that resilience depends more on what we receive than what we have. This study serves as a beginning point to guide future resilience research, practice, and implementation …

Informing Management Strategy For The Relict Leopard Frog (Rana Onca): Insights Into Breeding Biology And An Attempt To Improve Augmentation Success Through Pre-Exposure And Clearance Of An Emerging Amphibian Pathogen, Rebeca Rivera

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Relict Leopard Frog, Rana onca, is a species of conservation concern that suffered a decline sometime during the 20th century. Even after two decades of intensive management, the species currently only occupies 20 spring sites in southern Nevada and northwestern Arizona. The causes for the historical decline are mostly speculative, but relate to habitat loss, introduced predators, and emergent disease. Since 2001, R. onca has been under an intensive conservationprogram managed by a multiagency conservation team. There are several objectives specified in the program including the need to investigate the biology of the species and incorporate findings into …

Examination Of Performance Validity And The Relationship To Cognition And Symptoms In Schizophrenia Spectrum Disorders, Erick A. Rogers

UNLV Theses, Dissertations, Professional Papers, and Capstones

Approximately one-in-five individuals with psychotic disorders (i.e., schizophrenia spectrum disorders [SSD]) fail performance validity indicators (PVIs) during neurocognitive testing. Ensuring the validity of neurocognitive test results is necessary if the test scores are to be of use for diagnostic consideration, intervention selection and planning, predicting outcomes, and following changes in cognition over time in response to intervention, spontaneous recovery, or disease progression. PVIs are designed to require only a minimum level of engagement with the evaluation, which means nearly everyone is expected to “pass,” even those with moderate to severe brain damage. Traditional interpretations of PVI failure suggest a noncredible …

Restorative Justice Implementation: Examining The Effects Of White Fragility And Race On Implementation Of Restorative Justice Practices In Schools, Heather M. Thompson

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current zero-tolerance discipline policies are ineffective and contribute to disproportionality in school discipline. Restorative justice practices (RJP) are an equitable alternative approach to exclusionary practices. RJP has been used in schools prior to adequate research informing implementation, which has led to variability in implementation and outcomes. In particular, teacher willingness to participate in the implementation of RJP has been noted to be variable and limited among research studies. It is necessary to explore teacher attitudes to determine what underlies this lack of participation to inform the next steps for RJP implementation in schools. Specifically, since disparities in discipline are related …

Facial Expression Recognition Using Convolutional Neural Networks (Cnns) And Generative Adversarial Networks (Gans) For Data Augmentation And Image Generation, Shekhar Singh

UNLV Theses, Dissertations, Professional Papers, and Capstones

Facial expressions play a crucial role in human communication, serving as a powerful means to convey emotions. However, classifying facial expressions using artificial intelligence (AI) can be challenging, especially with small datasets and images. Facial Expression Recognition (FER) is an active area of research, with Convolutional Neural Networks (CNNs) being widely employed for classification. In this research, we propose a CNN-based approach for FER that utilizes both original and augmented datasets to enhance classification accuracy. Experimental results on the FER2013 dataset show test accuracies of 63.39% and 64.59% for the original and augmented datasets, respectively, in a seven-class classification task. …

Mob Family Proteins And Tricornered Kinase Are Required To Form Dorsal Appendages Of The Drosophila Eggshell, Keala H. D. Watson

UNLV Theses, Dissertations, Professional Papers, and Capstones

To understand how complex tissues are formed, we need to understand how cells communicate with other cells to build structures. In Drosophila melanogaster, epithelial cells form tubular structures to shape the dorsal appendages on the eggshells. One signaling pathway needed for this event is the Hippo-like kinase intracellular pathway. I focus on two key components in this pathway: the NDR kinase Tricornered (Trc) and Mob proteins. In eukaryotes, Mob proteins are known to interact with NDR kinases to promote their activation. The Hippo- like pathway involves the NDR kinase Trc; however, the specific Mob protein(s) that interact with Trc …

Measurement Invariance Of Impact In Bilingual And Monolingual High School Athletes, Hana Cecilia Kuwabara

UNLV Theses, Dissertations, Professional Papers, and Capstones

Given the reported negative consequences of sport related concussion (SRC), establishing the validity of concussion management tools is essential if they are used to determine the severity of concussion, track recovery or decline, implement effective interventions, and assist in return-to-play decision making. Previous research has found cognitive and symptoms differences on ImPACT, the most widely used SRC assessment measure, between monolingual and bilingual student athletes. Before further investigation of these differences can occur, measurement invariance of ImPACT must be established to ensure that differences are not attributable to measurement error. The current study has two aims: 1) to replicate a …

Development And Characterization Of Lead & Lead-Free Perovskite Solar Cell Materials, Rubaiya Murshed

UNLV Theses, Dissertations, Professional Papers, and Capstones

In recent years, perovskite photovoltaic technology has offered enormous viability and dimensionality in solar cell research. As a light-harvesting active layer, Perovskite generated remarkable development in device efficiency of 25.7% for the single-junction solar cell, and over 33% for the perovskite/silicon tandem solar cell. Also, perovskite-perovskite tandem solar cell (also called all-perovskite tandem solar cell) shows great potential in device performance and achieved a power conversion efficiency (PCE) of 26.4%. Transitioning photovoltaic technology from the laboratory to commercial products, high PCE, low cost, long lifetime, and low toxicity are some of the critical factors to consider during material selection. Pb-halide …

Identifying Clinical Profiles In A Community Sample Of Youth With Selective Mutism, Melanie Rede

UNLV Theses, Dissertations, Professional Papers, and Capstones

Selective mutism (SM) refers to a consistent failure to speak in social situations that have an expectation for speaking, despite fluent speech in other situations (American Psychiatric Association, 2013). Recent researchers describe SM as a heterogeneous disorder not always characterized by anxiety (Driessen et al., 2020). Specifically, some have argued that SM may be better explained as a neurodevelopmental rather than an anxiety disorder (Kearney & Rede, 2021). The aim of the present study was to find unique classes for anxiety, oppositional, and communication difficulties among youth with SM. Participants included 129 caregivers of youth with SM aged 6–14 years …

Development Of A Metapgs For Accurate Prediction Of Osteoporotic Fracture, Xiangxue Xiao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Introduction: Early identification of individuals at high-risk for osteoporotic fractures who may benefit from preventive intervention is essential. However, the predictive accuracy of the currently used fracture risk assessment tool remains suboptimal. The first aim of this research is to construct genome-wide polygenic scores for the femoral neck (PGS_FNBMD_idpred) and total body BMD (PGS_TBBMD_idpred) and to estimate their potential in identifying individuals with a high risk of osteoporotic fractures. The second aim is to validate the predictive performance of two previously established PGSs (PGS_FNBMD_idpred and PGS_TBBMD_idpred) in an external cohort …

Validity Of Fitbit And Garmin Devices While Ascending And Descending Flights Of Stairs, Alan Garcia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Two popular wearable fitness device brands are Fitbit and Garmin. The validity of Fitbit and Garmin’s wrist-worn devices in measuring step counts in various settings, such as walking up and down a staircase, is unclear. PURPOSE: To determine if four devices, the Fitbit Charge 2, Fitbit Versa 2, Garmin Fēnix 5 and Garmin Vívosmart HR+ record valid measures of step count when ascending and descending flights of stairs at three different speeds. METHODS: Twenty-eight participants (n=28) were tested individually. Two devices were randomly selected to be placed on each wrist. Participants climbed up and then down one, two, and three …

The Psychometric Properties Of The Modified Fear Of Falling Avoidance Behavior Questionnaire In Parkinson’S Disease And Older Adults, Billy La, Arturo Aldaco, Ashley Haller

UNLV Theses, Dissertations, Professional Papers, and Capstones

Background/purpose: The Fear of Falling Avoidance Behavior Questionnaire (FFABQ), developed in 2011 to measure fear of falling avoidance behavior, has good evidence for reliability and validity. However, a recently modified version (mFFABQ) is theorized to be easier to understand for those completing the questionnaire because the Likert responses are more logical in completing the item stem. The purpose of this study was to examine the test-retest reliability and construct validity of the mFFABQ in adults with Parkinson’s Disease (PD) and older adults aged 60-90 years. Methods: Thirty-nine participants (age 72.21 ± 9.5; 29 men, 10 women) diagnosed with PD (diagnosis …