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Autonomous Driving Trajectory Prediction
No full textAutonomous driving is undoubtedly one of the world\u27s most revolutionary technologies, opening the door to a more secure traffic environment. This innovation has led to vehicles being able to drive by themselves without the necessity of a person behind the wheel, as well as cruise control, lane-keeping assist, and automatic emergency braking. Unfortunately, there is still plenty of work before autonomous driving becomes more popular among drivers. While at UNLV as an undergraduate student/research assistant, one of my goals is to learn how these technologies work to bring ideas into the automotive industry by refining solutions to problems within these mechanisms. As for now, my task has been to explore how an autonomous vehicle functions under trajectory prediction. This is done by creating a dataset for algorithm training and testing it by annotating twenty-second sequences using lidar point cloud data. The goal is to evaluate prediction model performance and visualize its results for a more advanced/precise self-drivable vehicle experience. Ultimately, wouldn\u27t it be plausible to reduce the amount of stress linked with the dangers presented due to how distracted people behave on the road nowadays? Therefore, autonomous driving provides the possibility for public roads to minimize it.https://oasis.library.unlv.edu/durep_lightning/1037/thumbnail.jp
The Characterization of Cooperative String-pullung Behavior in Rats After Exposure to Space Flight Stressors
No full textAstronauts work cooperatively to complete tasks on missions through deep space where they will experience stressors, including radiation and sleep fragmentation, that may impair performance. Animals work together to achieve a common goal during cooperative tasks using string-pulling behaviors. While string-pulling behavior has revealed deficits in rat sensorimotor function after exposure to space flight stressors, it has yet to be determined if rats will engage in cooperative string-pulling or if these stressors will influence cooperation. Thus, to explore how space flight stressors impact cooperative behavior, female Wistar rats were exposed to either sham (n = 8) or 10 centi-grays of 250 MeV/n Helium (n = 8) and sleep fragmentation at ~6 months of age. During testing, rats were placed in two separate apparati sharing one string (0.2 cm diameter, 162 cm length, 100% cotton) and were required to pull in the string to retrieve Cheerio rewards simultaneously. Twelve trials/day were provided, and behavior was video recorded for offline analyses of cooperative performance, motivation, and sensorimotor function between groups. Irradiated rats took more days to reach criterion (cooperation on 8/12 trials) than sham rats. Criterion percentage was similar between groups once met; yet the amount of pulling between rat pairs during cooperative trials was greater for the sham group. These results suggest that a low dose exposure to Helium negatively impacts cooperation between female rats. If astronauts display similar disruptions after exposure to space flight stressors, then deleterious effects on team dynamics may arise and compromise mission success.https://oasis.library.unlv.edu/durep_posters/1220/thumbnail.jp
Investigating the Impact of Psychological Interventions on Autoimmune Disease Progression in Women
No full textAutoimmune disease arises when an individual\u27s immune system mistakenly attacks and damages the body’s tissues. Autoimmune disease disproportionately affects women, with eighty percent of diagnosed patients being female. This research proposal aims to explore the relationship between psychological factors (e.g., stress, anxiety, depression) and the progression of autoimmune diseases. This poster will propose a detailed study to assess whether reducing psychological distress through cognitive behavioral therapy (CBT) can slow disease progression. Cognitive behavioral therapy is a form of talk therapy to relieve symptoms of mental health conditions such as depression, anxiety, stress, or grief. Two hundred female patients diagnosed with an autoimmune disease (e.g., lupus, rheumatoid arthritis, psoriasis) will participate in the study and be randomly assigned to either an experimental or a control group. The experimental group will receive medical care for their autoimmune disease as well as psychological support through a twelve-week CBT program, consisting of two sessions a week for one hour. The control group will only receive medical care. Clinicians who are conducting CBT will track psychological progress through session notes. Physicians for all participants will monitor disease progression through medical tests including blood work, x-rays, and imaging. To track disease progression, initial tests ordered by physicians will be completed before the twelve-week CBT program begins and follow-up tests will be completed after completion of the CBT program. This study will evaluate if psychological improvements from CBT are associated with slower autoimmune progression in women.https://oasis.library.unlv.edu/durep_posters/1226/thumbnail.jp
Cellular Mechanisms of Embryonic Eye Regrowth in \u3cem\u3eXenopus Laevis\u3c/em\u3e
No full textThe African Clawed Frog, Xenopus laevis, has been an indispensable model organism for over 100 years in the study of embryogenesis and development. In recent years, this vertebrate model has emerged as a robust tool for deciphering the cellular and molecular mechanisms underlying various modes of tissue, limb, and organ regeneration. In the context of eye repair, Xenopus offers a unique model, where the adult frog eye has limited regenerative capacity compared to its pre-metamorphic embryonic and tadpole forms, which exhibit a robust capacity for regrowth. Understanding the intricate molecular mechanisms that underlie this developmental shift in regrowth ability has the potential to inform our efforts to develop future directed regenerative therapies for eye regrowth. However, to reach this point, a crucial first step of identifying the participating cell populations and intrinsic regenerative strategies used by Xenopus must be decoded. To this end, we have developed a lineage tracing protocol with EosFP, enabling precise labeling of cells within Xenopus laevis throughout its developmental stages. This method, now adapted for use in studying Xenopus eye development, has broadened our knowledge of the internal dynamics of multipotent retinal stem cells within the developing eye, a task not yet achieved with previous labeling technologies. This approach allowed for the labeling of select cells within the eye field through embryonic development, revealing that retinal progenitor cells (RPCs) proliferate and differentiate within their region of origin in the eye field to form the subsequent mature anatomy of the retina. Furthermore, by photoconverting Eos protein in the eye field and subsequently removing the labeled optic vesicle, we have shown that RPCs within the post-surgical wound serve as a source of regenerative cells for the embryonic Xenopus eye. Surprisingly, our results also suggest that cells within the optic fissure of the regenerating eye might originate from a non-RPC lineage. This work advances our understanding of eye development and regeneration in Xenopus, while providing a powerful new tool for future research. By deciphering the natural regenerative strategies employed by Xenopus, we open the door for facilitating directed therapies that mirror proven natural regrowth processes
Exercising Metabolism in Female Athletes with Low Energy Availability
No full textBACKGROUND. Low Energy Availability (LEA) is known to affect female athletes at significantly greater rates than male athletes and has unique consequences pertaining to female physiology such as the menstrual cycle, as well as deleterious effects on other organ systems. LEA has been implicated in the onset of cardiovascular diseases and increased cardiovascular risk, the presence of mental health disorders including depression and anxiety, altered energy storage, and increased rates of injury and illness. A particular age group of female athletes, young adults in college, are at an even higher risk of developing LEA compared to females of other age groups. This age (18–24 years) makes this population especially vulnerable to under-fueling, either by intentional restriction of calories or due to lack of food knowledge or access. Because this stage of life is also vital for creating a foundation of healthy habits that continue into adulthood, it is imperative to address these habits and understand the physiological and psychological effects under-fueling can have on these athletes. While many of the effects of LEA on health have been studied in detail over the last decade, some relationships are still not well understood. Studies in individuals with LEA have observed altered glycogen storage compared to those without LEA, which may alter their energy sources during exercise. Additionally, the known effects of LEA on cardiac structure and function indicate a potential effect on blood pressure which has been minimally investigated. Lastly, the relationship between LEA and depression has been observed in numerous studies. However, given the fact that college students are more likely to experience depression than other age groups warrants a deeper look into this relationship specifically within college-aged female athletes due to their elevated risk of both depression and LEA.
AIMS. The overall aim of this dissertation was to further investigate the relationship between LEA and metabolism, cardiovascular health, and mental health in NCAA Division I female athletes. The first specific aim was to determine whether substrate utilization at various exercise intensities in individuals with LEA was altered compared to those without LEA. The second specific aim was to investigate the potential relationship between LEA and blood pressure. The final aim of this dissertation was to determine the relationship between LEA and depression in this population.
METHODS. An observational study was designed to address the specific aims. NCAA Division I female athletes (ages 18–24) from numerous sports teams were recruited. They were assessed for LEA using the LEAF-Q, which has been validated to determine current energy availability status in female athletes. They then participated in the collection of resting blood pressure measurements as well as a treadmill protocol. The treadmill protocol was designed to include three three-minute intervals at 60%, 70%, and 80% of the participant\u27s VO2peak respectively. VO2 and VCO2 were measured during the treadmill protocol and used to calculate the oxidation rates of carbohydrates and fat at the different intensities. Participants also completed a General Health Questionnaire-12 (GHQ-12), which has been validated for determining the presence of depressive symptoms.
RESULTS. No differences were observed in carbohydrate or fat oxidation rates between participants with LEA and participants without LEA. Neither a relationship between LEA and blood pressure nor a relationship between LEA and depression was supported by the findings of this dissertation.
CONCLUSIONS. In this population of NCAA Division I female athletes, there were no differences in substrate utilization, blood pressure, or GHQ-12 scores between those with LEA and those without LEA. However, these findings may be different than we hypothesized due to the specific population chosen, as the hypotheses were based on studies completed in primarily elite athletes of a broader age range
Exploring Staff Nurses’ Perceptions of Nursing Student Enculturation Within Clinical Teaching: A Focused Ethnography
No full textThe traditional clinical education model in nursing has utilized on-site learning experiences in clinical settings with patient encounters. With the growing complexity and demands of contemporary nursing care today, it is imperative to question the principal assumptions that guide the design and use of traditional clinical teaching experiences. Staff nurses working with nursing students can illuminate the impact of sociocultural workplace factors on clinical teaching and learning when preparing students for practice. Yet there is little known about staff nurses’ perspectives of nursing culture and how enculturation prepares nursing students for the profession. By understanding the perceptions of enculturation among practice experts who teach nursing students in clinical environments, nursing professionals would gain insight about the culture of nursing and its effect on clinical teaching.
A focused ethnography serves to explore the culture and interactions of the acute care learning environment where nursing students’ formation takes place, the staff nurse’s perceptions of enculturation of nursing students in practice and its effect on teaching in the traditional clinical education model. Data will be collected through ethnographic observation processes and through informant interviews conducted in-person until saturation is achieved. Thematic analysis will be used to analyze data and result in themes of staff nurses’ perceptions of enculturation and what they truly value as the crux of clinical teaching. Achieving insight from staff nurses who help students learn the culture of nursing and are closely aligned with the practice world will add valuable evidence and be foundational for future research to radically transform the traditional clinical education model
New Insights into the Diverse Intraplate Volcanism Present within the Howland and Baker Island United States Exclusive Economic Zone
No full textThe origin of oceanic volcanism has been attributed to various mechanisms, such as upwelling mantle plumes, lithospheric extension driven decompression melting, and small-scale convective cells in the asthenosphere. Discovering the range of magmatic drivers present in the ocean basins aids in understanding mantle geodynamics and tectonic processes. A recent seafloor exploration campaign within the Howland and Baker Island (HBI) U.S. Exclusive Economic Zone (EEZ; approximately near the equator and the International Date Line) resulted in the collection of multiple lava flow samples, which offer valuable insights into the complex origins and dynamics of intraplate seamounts. According to current absolute plate motion (APM) models, the seamounts and islands that compose part of the HBI, as well as the Tokelau Seamount Chain to the south, was sourced by the long-lived Macdonald hotspot during the Late Cretaceous. This study utilizes new high precision 40Ar/39Ar age determinations, along with whole rock major and trace element analyses from previously unexplored seamounts, which help elucidate the volcanic history of the HBI EEZ during the Cretaceous.Three major age groups, each with their own geodynamic origins, are observed in the HBI EEZ. The new age data confirms a linear age progression at Howland Island (73.75 ± 0.28 Ma) and Titov Ridge (71.41 ± 0.23 Ma) aligning with the projected Macdonald hotspot track. The Unnamed Seamount 2 (85.61 ± 0.14 Ma) west of Howland Island (around 1.0 °N, 179.3 °E), does not fit the expected age or geometry of the Macdonald hotspot track. The origin of this seamount and neighboring Unnamed Seamount 3 remains enigmatic but may represent a pulse of plume melt channelization or similar anomalous short-lived volcanic activity. The oldest pulse of regional volcanism are tephra deposits (124.17 ± 0.12 Ma; 124.22 ± 0.13 Ma) from Unnamed Seamount 1 (around 3.9 °N, 176.3 °W). The deposits do not have chemistry consistent with mantle plume volcanism (i.e., deep melting and enriched reservoir rare earth element ratios) and are likely related either to the emplacement of the massive Ontong Java Plateau large igneous province on the Pacific basin at that time, or to plate deformation resulting from the adherence of the Magellan microplate onto the Pacific. These chemical and chronological findings from previously unexplored seamounts support the notion of the Macdonald Hotspot\u27s long-term activity extending to the Late Cretaceous and provide new perspectives on the variety of intraplate volcanism in oceanic basins
Electrical Contact to MoS2 for Sensitive Capacitance Measurements
No full textWhen electrons confined to two dimensions are subjected to a low temperature and high magnetic field environment, exact quantization of macroscopic material properties can occur, known as the integer (IQHE) and fractional (FQHE) quantum Hall effects. Important experimental platforms utilized to investigate the IQHE and FQHE are graphene-based van der Waals (vdW) heterostructures due to their high carrier mobility and easy access to low carrier density regimes. These heterostructures are limited in their scope however as graphene does not possess an energy band gap or strong spin-orbit coupling, two properties that lead to unique effects on the IQHE and FQHE. This is in stark contrast with other 2D materials such as the semiconducting transition metal dichalcogenides (TMDs) which contain both necessary ingredients. In this thesis, baseline measurements of penetration field capacitance (Cp) are confirmed on a monolayer graphene (MLG) vdW heterostructure at T = 3 K and B = 2 T, showing the ability to resolve features of electronic incompressibility. Cp and transport measurements are also presented on a few-layer MoS2 heterostructure, allowing a direct comparison between the two measurement techniques to resolve the conduction band edge of MoS2. Due to Schottky barrier formation between few-layer graphene contacts and MoS2, the resulting contact is non-ohmic, limiting measurements of Cp and transport to above 200 K. Concluding, a semimetallic bismuth contact method is investigated on a few-layer MoS2 sample, achieving multiple ohmic contacts with extracted Schottky barrier heights of 30 meV and -15 meV. The ohmic contact results in linear IV characteristics and large on-off ratios of 107 down to T = 3 K at low carrier densities n \u3c 3 10−12 cm−2. This work sets a foundation for sensitive capacitance measurements of the interesting class of TMDs in the low carrier density regime
Piezochromic Behavior of 2,4,6-Triphenylpyrylium Tetrachloroferrate
No full textIn advanced photonics, there is a growing interest in piezochromic luminescent materials that exhibit multicolor switching, driven by their potential applications in optical recording, memory, and sensors. Here, the piezochromic behavior of 2,4,6-triphenylpyrylium tetrachloroferrate (Py-FeCl4) under high pressures from 0 to 9 GPa is reported. The observed multicolor changing properties of Py-FeCl4 (yellow–orange–red–maroon–black) are found to be fully reversible upon decompression to ambient conditions. The mechanism of Py-FeCl4 piezochromism is investigated via Raman, infrared, and UV–vis spectroscopy combined with powder X-ray Diffraction. The absence of structural phase transitions as well as the abrupt shifts of bandgap values together with characteristic Raman and IR peaks within 0-9 GPa suggests that the Py-FeCl4 multicoloring switching behavior is driven by an electron transfer between the inorganic FeCl4− anion and the organic pyrylium cation. The obtained results demonstrate that Py-FeCl4 dye is a good candidate for developing high-pressure sensing technologies designed to function in extreme environments. Moreover, due to the inherent role of molecular-structure relationships in the pyrylium salt\u27s photophysical properties, findings suggest the potential discovery of piezochromic behavior in other pyrylium compounds
A Brief Early History of the UNLV Department of Geoscience
No full textThis project represents four years of part-time research and investigation. It started as something simple, a need for a spreadsheet for me, as a new Department Chair in January of 2020, to assemble the tenure and promotion timelines of existing faculty based on their employment starting dates. It then expanded to document every Geoscience faculty member, which revealed so many interesting stories along the way. Once it began it was hard to stop, with the research taking on a mind of its own as it meandered down the historical archive of the Department. And why stop with people? Buildings? Fair game. Cold War history? Radically radioactive! Geoscience softball team’s losing record? Shameful. It was all hoovered up and regurgitated in this document, such as it is.
In compiling this history, I would like to emphasize a few facts. First, because I only joined the Department in 2003, I was not a participant in these events, and had to rely on historical archives and documents. Chief among them are articles in the Rebel Yell, the Las Vegas Review Journal, Department newsletters, Department archives passed along from Chair to Chair, and the Board of Regent’s meetings archives. Many photos were found in the UNLV Special Collections. Second, insight into the developments of the Department relied heavily on the memories of the many founding faculty members who were able and willing to speak with me. Chief among them are Gene Smith, Rod Metcalf, the copious written record of ‘tribe scribe’ Dave Weide, Fred Bachhuber (whose position I filled when he became College of Science Dean), and Wanda Taylor, among others. To these esteemed colleagues, I express my sincere gratitude.
The nature of the archival record is incomplete; so too is this history. For example, there was much more information on tenure-track faculty than on staff or students, making the search for complete information challenging. I therefore had to focus mainly on faculty, roughly covering the time period from inception through the mid- to late-1990s when the PhD program began. This focus and timeline required omitting a lot of information, including a discussion of the actual research done by our faculty and students. Finally, any omissions not relating to the archival record or errors are my own, and for them I apologize in advance