Physical Sciences and Mathematics Commons^™

Dicationic Stilbazolium Salts: Structural, Thermal, Optical, And Ionic Conduction Properties, Pradip K. Bhowmik, Jung J. Koh, David King, Haesook Han, Benoît Heinrich, Bertrand Donnio, Daniel Zaton, Alfonso Martinez-Felipe

Chemistry and Biochemistry Faculty Research

Two series of new dicationic stilbazolium salts containing tosylate and triflimide counterions, respectively, were synthesized and characterized by spectroscopic techniques and elemental analysis. Despite of their promesogenic structures, none of these salts are mesomorphous, and instead they solely exhibit crystalline polymorphism, as deduced from differential scanning calorimetry, polarizing optical microscopy and variable temperature X-ray measurements. These salts were also found to be highly thermally stable with decomposition temperatures occurring well above 300 °C, and up to 367 °C for the triflimide salts, as determined by thermogravimetric analysis. UV–Vis absorption and photoluminescent properties were examined in both solution and in the …

Operating Solar Projects In Nevada, 2021, Kristian Thymianos, Saha Salahi, William E. Brown Jr.

Environment

The U.S. Energy Information Administration (EIA) and the Solar Energy Industries Association (SEIA) both provide national databases that contain comprehensive lists of active solar projects in the United States. This fact sheet provides a list of operating solar projects in the State of Nevada.

The “East Side” Of Las Vegas: A Latinx Historical Framework, Nathalie Martinez

Spectra Undergraduate Research Journal

Spanish heritage speakers in the United States are a reflection of everchanging linguistic and sociolinguistic pressures that result in myriad varieties across generations. This paper provides a preliminary historical framework to fill this gap of linguistic knowledge in the Spanish-speaking community of Las Vegas, Nevada. The goals were two-fold: (1) highlight the largest Spanish-speaking communities in Las Vegas and (2) explore the significance of the East Side in the history of the Latinx population of Las Vegas. Through the analysis of oral histories and historical works, the investigation highlights the Mexican, Salvadoran, and Cuban populations of Las Vegas and their …

Qualitative Review Of Educational Interventions For Improving Physical Activity Behaviors In Older Asian Americans In The United States, Raisa Kabir, Manoj Sharma, Sayeda Tazim Zaidi, Chia-Liang Dai

Spectra Undergraduate Research Journal

Physical activity (PA) provides numerous health benefits and minimizes chronic diseases and mental health issues, especially in older adults. The national survey data indicated that only 27.3% to 44.3% of older adults meet the recommended PA guidelines of 150 to 300 minutes/ week. There is limited data on PA behavior among older Asian American (AA) adults as very few to no local/national surveys have targeted these marginalized subgroups. This comprehensive review aims to identify existing PA intervention strategies and to update current knowledge on the effectiveness of these interventions to improve PA behavior among aging AA in the US. The …

The Future Of The Live Entertainment Tax In Southern Nevada, Katie M. Gilbertson

Spectra Undergraduate Research Journal

The Live Entertainment Tax (LET) in Nevada generated nearly one billion dollars during the 2019-2020 fiscal year. LET revenue all goes to the State General Fund, even though 97 percent of LET revenue is generated in Clark County. Nevada is experiencing an economic crisis, particularly in the tourism industry. Solutions from various fields suggest the best way to boost the local economy is to reinvest revenue in its original county. One policy solution Nevada policymakers should consider is to carve out a percentage of revenue generated by the LET to return directly back to Clark County to revitalize tourism.

Diabetes Mellitus Affects Working Memory, Dylone C. Braganza, Emmanuel Flores, Lauren A. Crew, Ryan A. Wirt, Andrew A. Ortiz, Adam M. Mcneela, Jefferson W. Kinney, James M. Hyman

Spectra Undergraduate Research Journal

Alzheimer’s disease (AD) degrades the brain’s ability to remember, think, and carry out tasks. The exact cause is not known, but several risk factors have been identified, including diabetes mellitus (DM). DM causes elevated blood sugar levels due to reduced insulin production in the pancreas. The linkage between elevated glucose levels and the behavioral impairments are not fully understood, which was the focus of this study. Rats were trained to alternate directions in a maze to receive a reward on consecutive trials. After training, five rats were injected with streptozotocin (STZ), which induces hyperglycemia by injuring pancreatic beta cells. Three …

A Timeline Of Discovery And Current Research On Primary Open-Angle Glaucoma And Emergence Of Potentially Permanent Treatment Solutions, Yonosuke Dejesus, Guadalupe Moreno Ceballos

Spectra Undergraduate Research Journal

This research examines the timeline of the discovery and research of Primary Open-Angle Glaucoma (POAG). By reviewing the literature on genetic and molecular mechanisms, we aim to emphasize a long-term treatment solution (iSTENT) to mitigate intraocular pressure (IOP) related to POAG etiology and disease progression. POAG is a multifactorial, autosomal dominant, adult-onset eye disease wherein the optic nerve cells become damaged due to a buildup of excess aqueous humor, resulting in increased IOP. Consequently, POAG leads to progressive loss of peripheral vision and is the leading cause of blindness in the US. Due to the multifactorial nature of glaucoma’s inheritance …

Racial Profiling: Understanding The Practice Of Stop-And-Frisk In New York City, Lisa Ly

Spectra Undergraduate Research Journal

Racial profiling has become a prominent issue in modern policing today. Instead of being based on individual suspicion, racial profiling embodies a belief that people of color are continuously singled out by the police for scrutiny and harassment. Policies and procedures make the Black community vulnerable to police discrimination and racial profiling. Floyd et al. v. City of New York et al. (2013) declared that the New York Police Department’s (NYPD) practice of stop-and-frisk was racially profiling Black civilians. This study sought (1) to determine if the NYPD post-Floyd is still engaging in racial profiling towards Black civilians; and (2) …

Free-Free Absorption In Hot Relativistic Flows: Application To Fast Radio Bursts, Esha Kundu, Bing Zhang

Physics & Astronomy Faculty Research

Magnetic flares create hot relativistic shocks outside the light cylinder radius of a magnetized star. Radio emission produced in such a shock or at a radius smaller than the shock undergoes free–free absorption while passing through the shocked medium. In this work, we demonstrate that this free–free absorption can lead to a negative drift in the frequency-time spectra. Whether it is related to the downward drift pattern observed in fast radio bursts (FRBs) is unclear. However, if the FRB down-drifting is due to this mechanism then it will be pronounced in those shocks that have isotropic kinetic energies ≳1044 erg. …

A Proposed Change To Astronaut Exposures Limits Is A Giant Leap Backwards For Radiation Protection, Francis A. Cucinotta, Walter Schimmerling, Eleanor A. Blakely, Tom K. Hei

Health Physics & Diagnostic Sciences Faculty Research

Addressing the uncertainties in assessing health risks from cosmic ray heavy ions is a major scientific challenge recognized by many previous reports by the National Academy of Sciences (NAS) and the National Council on Radiation Protection and Measurements (NCRP) advising the National Aeronautics and Space Administration (NASA). These reports suggested a series of steps to pursue the scientific basis for space radiation protection, including the implementation of age and sex dependent risk assessments and exposure limits appropriate for a small population of radiation workers, the evaluation of uncertainties in risk projections, and developing a vigorous research program in heavy ion …

Rotten With Prediction, Serena Raquel Hicks

UNLV Theses, Dissertations, Professional Papers, and Capstones

This project focuses on the relationship between religion and technology as it is portrayed in Science Fiction (SF). This thesis explores the SF genre rhetorically by examining the 2002 movie Minority Report (MR), which signaled the importance of surveillance and the need to predict future crimes following 9/11. The events of 9/11 played a significant role in post 9/11 SF films, which reflect and critique our communal and cultural values. 9/11 created a new relationship between the U.S justice system, predictive technologies (PTs), and data gathering. Through the Bush Doctrine of “preemptive action,” the U.S government attempted to use Dataism, …

Forecasting Pedestrian Trajectory Using Deep Learning, Arsal Syed

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this dissertation we develop different methods for forecasting pedestrian trajectories. Complete understanding of pedestrian motion is essential for autonomous agents and social robots to make realistic and safe decisions. Current trajectory prediction methods rely on incorporating historic motion, scene features and social interaction to model pedestrian behaviors. Our focus is to accurately understand scene semantics to better forecast trajectories. In order to do so, we leverage semantic segmentation to encode static scene features such as walkable paths, entry/exits, static obstacles etc. We further evaluate the effectiveness of using semantic maps on different datasets and compare its performance with already …

Hyperpolarizability Dispersion Measured For Carbon Disulfide Vapor, Rodrigo N. Fernandez

UNLV Theses, Dissertations, Professional Papers, and Capstones

The second hyperpolarizability (γ) of carbon disulfide (CS2) was measured by gas phase electric-field-induced second harmonic generation (ESHG), for laser wavelengths in the range of 765-1064 nm. The observed hyperpolarizability is decomposed into electronic (γ^e) and vibrational (γ^v) contributions, and the dispersion curve for γ^eis extrapolated to the static limit, with the result γ^e_0 = 12558 ± 93 atomic units. The results of this experiment agree with other recent nonlinear optical measurements and theoretical calculations.

Environmental Rhetoric And An Ecology Of Transcendence: A Rhetorical Criticism Of Awake, A Dream From Standing Rock, Alyssa Kahn

UNLV Theses, Dissertations, Professional Papers, and Capstones

My project blends Burkean theory with Indigenous rhetoric to argue that the counter- story of Awake proposes an ecology of transcendence to make sense of human-nature relationships. I wanted to analyze Awake A Dream From Standing Rock. The documentary is explicitly about Indigenous peoples. This documentary tells the story of the peaceful protests and resistance led by Native people at the Standing Rock Sioux Reservation or Lakota Tribe in North Dakota. The activists were protecting the water otherwise known as water protectors/warriors from the construction of the Dakota Access Pipeline (DAPL). The assembly of DAPL is intended to carry perforated …

A 155-Year Tree-Ring Based Record Of Warm And Dry Snow Droughts For The Cascade Range, Usa, Laura A. Dye

UNLV Theses, Dissertations, Professional Papers, and Capstones

Contributing 50-80% to the surface water for the region, mountain snowpack is a pillar of the hydrologic cycle in the western US, and is projected to decrease to 44% by 2100 in the Cascade Mountains alone. The western US has recently been identified as a global snow drought hot spot, exhibiting more frequent, intensified, and lengthened snow drought events in recent decades. Only recently has the need to understand the types of snow droughts and their driving mechanisms become critical to understand and quantify. Recent research suggests ‘warm’ snow droughts caused by winter precipitation falling as rain rather than snow …

Tail-Measurable Functions And Their Corresponding Induced Classes, And Some Determinacy Conditions Involving 3-Player Games, Joshua K. Reagan

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this dissertation, we have two main categories of results. The first is regarding certain point-classes, and the second is regarding 3-player games.

The point-classes of Baire Space, \mathcal{N}, in the Borel and Projective Hierarchies, as well as Hausdorff's Difference Hierarchy have been well studied, and there has been much research into further stratifying these hierarchies. One area of particular interest falls in between the point-classes \mathbf{\Pi}_\mathbf{1}^\mathbf{1} and \Delta\left(\omega^2-\mathbf{\Pi}_\mathbf{1}^\mathbf{1}\right). It is well known that the point-classes \beta-\mathbf{\Pi}_\mathbf{1}^\mathbf{1}, for \beta\in\omega^2, stratify this region of the projective hierarchy, with the point-class \bigcup_{\beta\in\omega^2}\beta-\mathbf{\Pi}_\mathbf{1}^\mathbf{1} still falling strictly below \Delta\left(\omega^2-\mathbf{\Pi}_\mathbf{1}^\mathbf{1}\right). Dr. Derrick DuBose developed multiple …

On-Chip Terahertz Time-Domain Spectroscopy, Randy Sterbentz

UNLV Theses, Dissertations, Professional Papers, and Capstones

Terahertz time-domain spectroscopy (THz-TDS) allows the direct measurement of optical and charge carrier properties of materials in a region of the electromagnetic spectrum inaccessible to most other spectroscopic techniques. We have adapted the technique to an on-chip arrangement that allows us to measure these properties in nanoscale materials with dimensions below the diffraction limit. In this thesis, we present the operation of instruments and the mechanics behind performing on-chip terahertz time-domain spectroscopy. Three materials were tested to confirm the capabilities of our system to measure THz radiation: indium selenide (InSe), radiation-damaged silicon-on-sapphire (RD-SOS), and an erbium arsenide:gallium arsenide superlattice. Preliminary …

Functional Π-Organogelators: From Nanoribbons To Organic Phosphors, Sae Hui Lee

UNLV Theses, Dissertations, Professional Papers, and Capstones

π-Conjugated systems have been receiving notable attention in the field of organic material chemistry due to their interesting optical properties, assembling properties, and potential application in optoelectronics. Among various self-assembly methods, organogelation has been known to allow facile and easily reproducible molecular assembly. This work focuses on creating new π-organogelators with various side group modifications which in result allow proper tuning of the optical properties along with an effective self-assembly upon gelation. The research comprises of two chapters: 1) the first chapter focuses on N-heteroacenes (NHAs) with gelation property and 2) the second chapter investigates gelation induced phosphorescence (GIP) of …

Localization Of Native Mms13 To The Magnetosome Chain Of Magnetospirillum Magneticum Amb-1 Using Immunogold Electron Microscopy, Immunofluorescence Microscopy And Biochemical Analysis, Zachery Oestreicher, Carmen Valverde-Tercedor, Eric Mumper, Lumarie Pérez-Guzmán, Nadia N. Casillas-Ituarte, Concepcion Jimenez-Lopez, Dennis A. Bazylinski, Steven K. Lower, Brian H. Lower

Life Sciences Faculty Research

Magnetotactic bacteria (MTB) biomineralize intracellular magnetite (Fe3O4 ) crystals surrounded by a magnetosome membrane (MM). The MM contains membrane-specific proteins that control Fe3O4 mineralization in MTB. Previous studies have demonstrated that Mms13 is a critical protein within the MM. Mms13 can be isolated from the MM fraction of Magnetospirillum magneticum AMB-1 and a Mms13 homolog, MamC, has been shown to control the size and shape of magnetite nanocrystals synthesized in-vitro. The objective of this study was to use several independent methods to definitively determine the localization of native Mms13 in M. magneticum AMB-1. Using Mms13-immunogold labeling and transmission electron microscopy …

A Mechanical Model For Magnetized Relativistic Blastwaves, Shunke Ai, Bing Zhang

Physics & Astronomy Faculty Research

The evolution of a relativistic blastwave is usually delineated under the assumption of pressure balance between forward- and reverse-shocked regions. However, such a treatment usually violates the energy conservation law, and is inconsistent with existing magnetohydrodynamic numerical simulation results. A mechanical model of non-magnetized blastwaves was proposed in previous work to solve the problem. In this paper, we generalize the mechanical model to the case of a blastwave driven by an ejecta with an arbitrary magnetization parameter $\sigma_{\rm ej}$. We test our modified mechanical model by considering a long-lasting magnetized ejecta and found that it is much better than the …

Evaluating Irrigation Performance And Water Productivity Using Eeflux Et And Ndvi, Usha Poudel, Haroon Stephen, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Southern California’s Imperial Valley (IV) faces serious water management concerns due to its semi-arid environment, water-intensive crops and limited water supply. Accurate and reliable irrigation system performance and water productivity information is required in order to assess and improve the current water management strategies. This study evaluates the spatially distributed irrigation equity, adequacy and crop water productivity (CWP) for two water-intensive crops, alfalfa and sugar beet, using remotely sensed data and a geographical information system for the 2018/2019 crop growing season. The actual crop evapotranspiration (ETa) was mapped in Google Earth Engine Evapotranspiration Flux, using the linear interpolation method in …

Barriers To And Uncertainties In Understanding And Quantifying Global Critical Mineral And Element Supply, Brian A. Mcnulty, Simon M. Jowitt

Geoscience Faculty Research

The critical minerals and elements are natural substances that are essential to modern life but have insecure supply. This lack of a secure supply clashes with the increasing importance of these elements, especially given their use in technologies needed to reduce global CO2 emissions and mitigate against anthropogenic climate change. In this contribution we review the by-product nature of the critical minerals and elements and the inherant uncertainties in reported critical mineral and element annual production as well as the relationships between these commodities and main-product metals and associated concentrates. We explore the geological and geographical barriers to critical mineral …

A Survey On Securing Iot Ecosystems And Adaptive Network Vision, Tejaswini Goli, Yoohwan Kim

Computer Science Faculty Research

The rapid growth of Internet-of-Things (IoT) devices and the large network of interconnected devices pose new security challenges and privacy threats that would put those devices at high risk and cause harm to the affiliated users. This paper emphasizes such potential security challenges and proposes possible solutions in the field of IoT Security, mostly focusing on automated or adaptive networks. Considering the fact that IoT became widely adopted, the intricacies in the security field tend to grow expeditiously. Therefore, it is necessary for businesses to adopt new security protocols and to the notion of automated network security practices driven by …

Recovery Of High Specific Activity Molybdenum-99 From Accelerator-Induced Fission On Low-Enriched Uranium For Technetium-99m Generators, M. Alex Brown, Nathan Johnson, Artem V. Gelis, Milan Stika, Anna G. Servis, Alex Bakken, Christine Krizmanich, Kristin Shannon, Peter Kozak, Amanda Barnhart, Chad Denbrock, Nicolas Luciani, Terry Grimm, Peter Tkac

Chemistry and Biochemistry Faculty Research

A new process was developed to recover high specific activity (no carrier added) 99Mo from electron-accelerator irradiated U3O8 or uranyl sulfate targets. The process leverages a novel solvent extraction scheme to recover Mo using di(2-ethylhexyl) phosphoric acid following uranium and transuranics removal with tri-n-butyl phosphate. An anion-exchange concentration column step provides a final purification, generating pure 99Mo intended for making 99Mo/99mTc generators. The process was demonstrated with irradiated uranium targets resulting in more than 95% 99Mo recovery and without presence of fission products or actinides in the product.

Special Issue Editorial: Current Advances In Liquid Crystals, Pradip K. Bhowmik

Chemistry and Biochemistry Faculty Research

No abstract provided.

Β -Technetium: An Allotrope With A Nonstandard Volume-Pressure Relationship, Emily Siska, Dean Smith, Christian Childs, Daniel Koury, Paul M. Forster, Keith V. Lawler, Ashkan Salamat

Chemistry and Biochemistry Faculty Research

We report the synthesis and structure of the second allotrope of technetium, β-Tc. Transformative pathways are accessed at extreme conditions using the laser-heated diamond anvil cell and confirmed with in situ synchrotron x-ray diffraction and Raman spectroscopy. β-Tc is fully recoverable to ambient conditions, although counter to our DFT calculations predicting a face-centered-cubic lattice, we observe a tetragonal structure (I4/mmm) that exhibits further tetragonal distortion with pressure. β-Tc has an expanded volume relative to the hcp ground state phase, that when doped with nitrogen has an unexpected volume lowering. Such anomalous behavior is possibly indicative of a rare electronic phase …

Impact Of Neoantigen Expression And T-Cell Activation On Breast Cancer Survival, Wenjing Li, Amei Amei, Francis Bui, Saba Norouzifar, Lingeng Lu, Zuoheng Wang

Mathematical Sciences Faculty Research

Neoantigens are derived from tumor-specific somatic mutations. Neoantigen-based syn-thesized peptides have been under clinical investigation to boost cancer immunotherapy efficacy. The promising results prompt us to further elucidate the effect of neoantigen expression on patient survival in breast cancer. We applied Kaplan–Meier survival and multivariable Cox regression models to evaluate the effect of neoantigen expression and its interaction with T-cell activation on overall survival in a cohort of 729 breast cancer patients. Pearson’s chi-squared tests were used to assess the relationships between neoantigen expression and clinical pathological variables. Spearman correlation analysis was conducted to identify correlations between neoantigen expression, mutation …

How State Interventions Affect Municipalities Taking The Lead In Sustainability, Jayce L. Farmer, Andres J.Rodriguez Lombeida

Public Policy and Leadership Faculty Publications

The state and local governments throughout the United States interact within a complex system of multilevel governance to advance sustainability. However, we know little about what this hierarchical system of exchanges means for municipalities as they work to achieve energy efficient government operations. Drawing on a perspective of “contested federalism”, we examine how the transaction costs of state–local government relations affect the efforts of U.S. cities to lead by example and promote sustainability within their internal processes. We apply a Bayesian item response theory approach to assess the effects of state-level fiscal and policy interventions on municipal commitments to energy …

Bountychain: Toward Decentralizing A Bug Bounty Program With Blockchain And Ipfs, Alex Hoffman, Phillipe Austria, Chol Hyun Park, Yoohwan Kim

Computer Science Faculty Research

Bug Bounty Programs (BBPs) play an important role in providing and maintaining security in software applications. These programs allow testers to discover and resolve bugs before the general public is aware of them, preventing incidents of widespread abuse. However, they have shown problems such as organizations providing accountability of reporting bugs and nonrecognition of testers. In this paper, we discuss Bountychain, a decentralized application using Ethereum-based Smart Contracts (SCs) and the Interplanetary File System (IPFS), a distributed file storage system. Blockchain and SCs provide a safe, secure and transparent platform for a BBP. Testers can submit bug reports and organizations …

Colossal Density-Driven Resistance Response In The Negative Charge Transfer Insulator Mns2, Dylan Durkee, Nathan Dasenbrock-Gammon, G. Alexander Smith, Elliot Snider, Dean Smith, Christian Childs, Simon A.J. Kimber, Keith V. Lawler, Ranga P. Dias, Ashkan Salamat

Chemistry and Biochemistry Faculty Research

A reversible density driven insulator to metal to insulator transition in high-spin MnS2 is experimentally observed, leading with a colossal electrical resistance drop of 108 ω by 12 GPa. Density functional theory simulations reveal the metallization to be unexpectedly driven by previously unoccupied S22- σ3p∗ antibonding states crossing the Fermi level. This is a unique variant of the charge transfer insulator to metal transition for negative charge transfer insulators having anions with an unsaturated valence. By 36 GPa the emergence of the low-spin insulating arsenopyrite (P21/c) is confirmed, and the bulk metallicity is broken with the system returning to an …