Digital Commons Network^™

Investigating The Future Potential Of An Upgraded Alma To Image Planet-Forming Disks At Sub-Astronomical-Unit Scales, Benjamin P. Burrill, Luca Ricci, Sarah K. Harter, Shangjia Zhang, Zhaohuan Zhu

Physics & Astronomy Faculty Research

In recent years, ALMA has been able to observe large-scale substructures within protoplanetary disks. Comparison with the predictions from models of planet–disk interactions has indicated that most of these disk substructures can be explained by the presence of planets with the mass of Neptune or larger at orbital radii of ≈5–100 au. Better resolution is needed to observe structures closer to the star, where terrestrial planets are expected to form, as well as structures opened by planets with masses lower than Neptune. We investigate the capabilities of a possible extension to ALMA that would double the longest baseline lengths in …

Dark Fluxes From Accreting Black Holes Through Several Mechanisms, Rong-Gen Cai, Sichun Sun, Bing Zhang, Yun-Long Zhang

Physics & Astronomy Faculty Research

We discuss the possibility that accreting black hole systems can be sources for dark matter flux through several different mechanisms. We firstly discuss two types of systems‘: coronal thermal plasmas around supermassive black holes in active galactic nuclei (AGNs), and accretion disks of stellar-mass X-ray black hole binaries (BHBs). We explore how these black hole systems may produce keV light dark matter fluxes and find that the dark fluxes from those sources might be too weak to account for the current XENON1T excess. On the other hand, black holes can be good accelerators to accrete and boost heavy dark matter …

Trends In Scientific Output On The Lesbian, Gay, Bisexual, And Transgender (Lgbt) Community Research: A Bibliometric Analysis Of The Literature, David An, Kavita Batra

School of Medicine Faculty Research

Introduction: Lesbian, Gay, Bisexual, and Transgender (LGBT) represent a diverse group with special needs due to the unusual developmental experiences and social inequalities. This paper aims to explore and outline a future research direction in LGBT issues through tracing our historical understanding of this population from an aspect of scientific research. Methods: LGBT-related peer-reviewed documents were retrieved from the PubMed database and the study period was set from the inception to 2021. Python-based methods were then performed to analyze the publication metadata and extract the most prominent research topics based on the abstract contents. Key points covered in the study …

Teachers’ Exposure To Professional Development And The Quality Of Their Instructional Technology Use: The Mediating Role Of Teachers’ Value And Ability Beliefs, Margaret A. Bowman, Vanessa W. Vongkulluksn, Zilu Jiang, Kui Xie

Educational Psychology, Leadership, and Higher Education Faculty Research

© 2020 The Author(s). Published with license by Taylor & Francis Group, LLC. One way to help teachers use technology effectively is through professional development (PD). However, understanding of how exposure to PD relates to teachers’ personal characteristics is limited. The purpose of this research was to investigate the relationships among PD exposure, teachers’ abilities and values, and teachers’ quality of technology integration according to Bloom’s taxonomy. By surveying 724 middle and high school teachers, and using structural equation modeling, this study showed that values mediate the influence of PD exposure on technology integration. Results suggest that PD may be …

Circumbinary Disk Evolution In The Presence Of An Outer Companion Star, Rebecca G. Marin, Stephen Lepp, Stephen H. Lubow, Matthew A. Kenworthy, Grant M. Kennedy, David Vallet

Physics & Astronomy Faculty Research

We consider a hierarchical triple system consisting of an inner eccentric binary with an outer companion. A highly misaligned circumbinary disk around the inner binary is subject to two competing effects: (i) nodal precession about the inner binary eccentricity vector that leads to an increase in misalignment (polar alignment) and (ii) Kozai–Lidov (KL) oscillations of eccentricity and inclination driven by the outer companion that leads to a reduction in the misalignment. The outcome depends upon the ratio of the timescales of these effects. If the inner binary torque dominates, then the disk aligns to a polar orientation. If the outer …

Macroscale Robust Superlubricity On Metallic Nbb2, Jia Wang, Chang Liu, Kaifei Miao, Kan Zhang, Weitao Zheng, Changfeng Chen

Physics & Astronomy Faculty Research

Robust superlubricity (RSL), defined by concurrent superlow friction and wear, holds great promise for reducing material and energy loss in vast industrial and technological operations. Despite recent advances, challenges remain in finding materials that exhibit RSL on macrolength and time scales and possess vigorous electrical conduction ability. Here, the discovery of RSL is reported on hydrated NbB2 films that exhibit vanishingly small coefficient of friction (0.001–0.006) and superlow wear rate (≈10−17 m3 N−1 m−1) on large length scales reaching millimeter range and prolonged time scales lasting through extensive loading durations. Moreover, the measured low resistivity (≈10−6 Ω m) of the …

Misalignment Of Terrestrial Circumbinary Planets As An Indicator Of Their Formation Mechanism, Anna C. Childs, Rebecca G. Martin

Physics & Astronomy Faculty Research

Circumbinary gas disks are often observed to be misaligned with the binary orbit, suggesting that planet formation may proceed in a misaligned disk. With n-body simulations, we consider the formation of circumbinary terrestrial planets from a particle disk that is initially misaligned. We find that if terrestrial planets form in this way, in the absence of gas, they can only form close to coplanar or close to polar to the binary orbit. Planets around a circular binary form coplanar while planets around an eccentric binary can form coplanar or polar depending on the initial disk misalignment and the binary eccentricity. …

Cellular Dna Effects Of Radiation And Cancer Risk Assessment In Cells With Mitochondrial Defects, J. Chen, D. M. Sridharan, C. L. Cross, J. M. Pluth

Epidemiology & Biostatistics Faculty Research

Mitochondria play a key role in mediating non-targeted effects (NTE) post-radiation exposure. Mitochondrial DNA (mtDNA), due to its less efficient repair as compared to nuclear DNA, is more severely affected by radiation exposure and mutations in essential mtDNA genes can further exacerbate oxidative stress. Our objective was to evaluate the impact of mitochondrial defects on radiation-induced DDR and genomic instability, biomarkers that can foreshadow cancer development. To better understand this relationship, we used commercially available lymphoblastoid cell lines containing characterized mitochondrial mutations and studied the kinetics of DNA damage and relative telomere length (RTL) changes over time post 0.5 Gy …

Asteroids And Life: How Special Is The Solar System?, Rebecca G. Martin, Mario Livio

Physics & Astronomy Faculty Research

Asteroid impacts with Earth may have played an essential role in the emergence of life on Earth through their creation of favorable niches for life, changes to the atmosphere, and delivery of water. Consequently, we suggest two potential requirements for life in an exoplanetary system: first, that the system has an asteroid belt, and second, that there is a mechanism to drive asteroids to impact the terrestrial habitable planet. Since in the solar system the ν6 secular resonance has been shown to have been important in driving these impacts, we explore how the masses and locations of two giant planets …

2014-2019 National Science Foundation (Nsf) Rankings By Total R&D Expenditures, Katie M. Gilbertson, Caitlin J. Saladino, William E. Brown Jr.

Higher Education

This fact sheet presents National Science Foundation (NSF) funding data for 10 individual research universities in addition to the combined funding received by the University of Nevada, Las Vegas (UNLV) and the University of Nevada, Reno (UNR) for the years 2014 to 2019.

What Tourists Want, A Sustainable Paradise, Catherine Linnes, Jerome Agrusa, Giulio Ronzoni, Joseph Lema

Hospitality Faculty Research

The increasing complexity of tourism and sustainability offers opportunities and challenges among diverse stakeholder perspectives. The need for sustainable and nature-based approaches exists throughout the growing body of literature from among a number of dimensions and measures. One of the overarching goals of the paper is to examine whether tourists will choose a destination or hotel that is actively working to improve the environment while examining how Hawaii’s tourism is nature-based as well as other measures of sustainability while enjoying a slice of paradise in the Hawaiian Islands. This study explores tourism sustainability concerns in Hawaii, such as the influence …

Separating Non-Linear Optical Signals Of A Sample From High Harmonic Radiation In A Soft X-Ray Free Electron Laser, Toshihide Sumi, Masafumi Horio, Tomoaki Senoo, Tetsuya Wada, Yuki Tsujikawa, Xiaoni Zhang, Paul Manset, Mihoko Araki, Yasuyuki Hirata, Walter S. Drisdell, John W. Freeland, Angelique Amadno, Michael Zuerch, Yuya Kubota, Shigeki Owada, Kensuke Tono, Makina Yabashi, Craig P. Schwartz, Iwao Matsuda

Nevada Extreme Conditions Laboratory Faculty Research

Second harmonic generation (SHG) is a unique non-linear optical effect that can be used to investigate chemical states of molecules at surfaces/interfaces. By the use of soft X-rays, SHG gains element selectivity through the inner-core excitation resonance. However, it is challenging to observe SHG signals separately from the second-order light generated from the undulator. Here, we report a new ellipsometry method for soft X-ray SHG to suppress the contribution of second-harmonic radiation from the light source. Through measurements of a GaAs(100) crystal, we demonstrate that pure SHG signals can be obtained for the horizontally polarized component. The present method is …

Arsenic Mineral In Volcanic Tuff, A Source Of Arsenic Anomaly In Groundwater: City Of Chihuahua, Mexico, Minghua Ren, José A. Rodríguez-Pineda, Philip Goodell

Geoscience Faculty Research

Arsenic is a naturally occurring trace element that causes many health effects when present in drinking water. Elevated arsenic concentrations in water are often attributed to nearby felsic volcanic sequences; however, the specific rock units to which the groundwater anomalies can be accredited are rarely identified. The groundwater from wells around the city of Chihuahua, Mexico, contains high arsenic content. Arsenic in groundwater increases toward the base rock containing Tertiary volcanic rocks. Through detailed scanning electron microscope (SEM) and electron microprobe (EMP) work, arsenic minerals are identified in the cavities of the Tertiary volcanic tuff from the northeast part of …

Subthreshold Vibration Influences Standing Balance But Has Unclear Impact On Somatosensation In Persons With Transtibial Amputations, Zachary S. Meade, Aaron D. Likens, Jenny A. Kent, Kota Z. Takahashi, Shane R. Wurdeman, Adam L. Jacobsen, Manuel E. Hernandez, Nick Stergiou

Physical Therapy Faculty Research

Stochastic resonance has been successfully used to improve human movement when using subthreshold vibration. Recent work has shown promise in improving mobility in individuals with unilateral lower limb amputations. Furthering this work, we present an investigation of two different signal structures in the use of stochastic resonance to improve mobility in individuals with unilateral lower limb amputations. Cutaneous somatosensation and standing balance measures using spatial and temporal analysis were assessed. There were no differences in the somatosensation measures, but differences in the temporal characteristics of the standing measures were seen with the various vibration structures when compared to no vibration, …

Perspectives Of Orthodontists Of The Diagnosis, Prevention, And Management Of White Spot Lesions: A Qualitative Study, Salwa Taibah, Neamat Hassan Abubakr Hassan, Hassan Ziada

Dental Medicine Faculty Research

Aims: Several factors influence the development of white spot lesions (WSLs), and one of these is fixed orthodontic appliances. This study aims to evaluate the awareness, preventive strategies, and management of WSLs among a group of Orthodontists. Materials and Methods: A qualitative methodology was applied; four focus groups made up a purposive sample from Orthodontists with various training backgrounds while working within the same healthcare services. Results: Three main themes emerged: awareness and ability to diagnose WSLs, perceived influences on the development of WSLs, and prevention and management strategies and barriers to care delivery. All focus groups agreed that there …

Eccentric Dust-Ring Formation In Kozai-Lidov Gas Disks, Rebecca G. Martin, Stephen H. Lubow

Physics & Astronomy Faculty Research

A highly misaligned gas disk around one component of a binary star system can undergo global Kozai-Lidov (KL) oscillations for which the disk inclination and eccentricity are exchanged. With hydrodynamical simulations of a gas and dust disk we explore the effects of these oscillations on the dust density distribution. For dust that is marginally coupled to the gas (St ≈ 1), we find that the dust undergoes dynamical behavior similar to that of the gas disk but the radial distribution of dust may be very different from that of the gas. The inward radial drift of the dust is faster …

Diamond And Methane Formation From The Chemical Decomposition Of Polyethylene At High Pressures And Temperatures, E. B. Watkins, R. C. Huber, C. M. Childs, Ashkan Salamat, J. S. Pigott, P. Chow, Y. Xiao, J. D. Coe

Physics & Astronomy Faculty Research

Polyethylene (C2H4)n was compressed to pressures between 10 and 30 GPa in a diamond anvil cell (DAC) and laser heated above 2500 K for approximately one second. This resulted in the chemical decomposition of the polymer into carbon and hydrocarbon reaction products. After quenching to ambient temperature, the decomposition products were measured in the DAC at pressures ranging from ambient to 29 GPa using a combination of x-ray diffraction (XRD) and small angle x-ray scattering (SAXS). XRD identified cubic diamond and methane as the predominant product species with their pressure–volume relationships exhibiting strong correlations to the diamond and methane equations …

Artificial Intelligence Framework Identifies Candidate Targets For Drug Repurposing In Alzheimer’S Disease, Jiansong Fang, Pengyue Zhang, Quan Wang, Chien Wei Chiang, Yadi Zhou, Yuan Hou, Jielin Xu, Rui Chen, Bin Zhang, Stephen J. Lewis, James B. Leverenz, Andrew A. Pieper, Bingshan Li, Lang Li, Jeffrey Cummings, Feixiong Cheng

Brain Health Faculty Research

Background: Genome-wide association studies (GWAS) have identified numerous susceptibility loci for Alzheimer’s disease (AD). However, utilizing GWAS and multi-omics data to identify high-confidence AD risk genes (ARGs) and druggable targets that can guide development of new therapeutics for patients suffering from AD has heretofore not been successful. Methods: To address this critical problem in the field, we have developed a network-based artificial intelligence framework that is capable of integrating multi-omics data along with human protein–protein interactome networks to accurately infer accurate drug targets impacted by GWAS-identified variants to identify new therapeutics. When applied to AD, this approach integrates GWAS findings, …

Sun Tunnels (1973-76) By Nancy Holt: One Earthwork's Interdisciplinary Approach, Hikmet Loe

Creative Collaborations

In 1973, American artist Nancy Holt (1938-2014) extended her studio practice into the land, employing light, vision, and perception through photography, film, installations, and poetics. By creating her monumental earthwork Sun Tunnels (1973-76), Holt became a leader within Land art, one of the few female artists working in a male-dominated discipline.

Sun Tunnels—located near the border of Western Utah and Eastern Nevada—is comprised of four concrete tunnels placed in an “X” pattern on the Great Salt Lake Desert’s alkaline floor. Each tunnel measures 18’ (L) x 9’ 2 1⁄2” (D); the overall work measures 9’ 2 1⁄2” x 68’ …

Evaluation Of Continuous Power-Down Schemes, James Andro-Vasko, Wolfgang Bein

Computer Science Faculty Research

We consider a power-down system with two states—“on” and “off”—and a continuous set of power states. The system has to respond to requests for service in the “on” state and, after service, the system can power off or switch to any of the intermediate power-saving states. The choice of states determines the cost to power on for subsequent requests. The protocol for requests is “online”, which means that the decision as to which intermediate state (or the off-state) the system will switch has to be made without knowledge of future requests. We model a linear and a non-linear system, and …

Novel Architecture Of Onem2m-Based Convergence Platform For Mixed Reality And Iot, Seungwoon Lee, Woogeun Kil, Byeong Hee Roh, Si-Jung Kim, Jin Suk Kang

College of Engineering Faculty Research

There have been numerous works proposed to merge augmented reality/mixed reality (AR/MR) and Internet of Things (IoT) in various ways. However, they have focused on their specific target applications and have limitations on interoperability or reusability when utilizing them to different domains or adding other devices to the system. This paper proposes a novel architecture of a convergence platform for AR/MR and IoT systems and services. The proposed architecture adopts the oneM2M IoT standard as the basic framework that converges AR/MR and IoT systems and enables the development of application services used in general-purpose environments without being subordinate to specific …

An Integrative Approach To Teaching In Precalculus And Calculus Classes, Aleksei Talonov

UNLV Best Teaching Practices Expo

We would like to present practices of using problem-based learning activities in Mathematics classroom. We mostly concentrated our attention on Precalculus and Calculus classes which have had low success rates and retention. During the last couple of years, we developed a set of course specific materials in the form of lecture notes and inclass and out-of-class assignments. Each major assignment is accompanied by clear and coherent guidelines explaining what kind of skills will be attained by practicing this assignment, how it can be done, what amount of time can it reasonably take, when is it due, and where to get …

An Approach For Material Model Identification Of A Composite Coating Using Micro-Indentation And Multi-Scale Simulations, Pouya Shojaei, Riccardo Scazzosi, Mohamed Trabia, Brendan O’Toole, Marco Giglio, Xing Zhang, Yiliang Liao, Andrea Manes

Mechanical Engineering Faculty Research

While deposited thin film coatings can help enhance surface characteristics such as hardness and friction, their effective incorporation in product design is restricted by the limited understand-ing of their mechanical behavior. To address this, an approach combining micro-indentation and meso/micro-scale simulations was proposed. In this approach, micro-indentation testing was conducted on both the coating and the substrate. A meso-scale uniaxial compression finite element model was developed to obtain a material model of the coating. This material model was incorporated within an axisymmetric micro-scale model of the coating to simulate the indentation. The proposed approach was applied to a Ti/SiC metal …

Conatus, The Will To Persist: An Introduction, Jasmin Özel, Nikos Psarros

Philosophy Faculty Research

The papers collected in this issue address a variety of aspects of the concept of conatus ranging from the explorations of its roots in early ancient Greek thought to its application on modern theories of democratic education. The conatus is a special relation between the parts of a monad and their subparts and the subparts of the subparts to infinity, which ensures that each part and subpart is a part of this monad and not of any other. As a fundamental trait of monadic existence, the conatus is manifested in a multiplicity of facets that sustain the persistence of any …

Stability And Mechanical Properties Of W1-X Mox B4.2 (X=0.0-1.0) From First Principles, Weiguang Gong, Rui Xu, Xuecheng Shao, Quan Li, Changfeng Chen

Physics & Astronomy Faculty Research

Heavy transition-metal tetraborides (e.g., tungsten tetraboride, molybdenum tetraboride, and molybdenum-doped tungsten tetraboride) exhibit superior mechanical properties, but solving their complex crystal structures has been a long-standing challenge. Recent experimental x-ray and neutron diffraction measurements combined with first-principles structural searches have identified a complex structure model for tungsten tetraboride that contains a boron trimer as an unusual structural unit with a stoichiometry of 1:4.2. In this paper, we expand the study to binary MoB4.2 and ternary W1-xMoxB4.2 (x=0.0-1.0) compounds to assess their thermodynamic stability and mechanical properties using a tailor-designed crystal structure search method in conjunction with first-principles energetic calculations. Our …

21st-Century Skillset Perceptions Of Students In An Information Technology Career Academy Compared To Those At A Comprehensive School, Edward C. Fletcher Jr., Amber D. Dumford

Journal of Research in Technical Careers

In this study, we compared the perspectives of students’ 21st-Century competencies (critical thinking and communication, applied learning, and intrapersonal and interpersonal skills) based on participating in an urban magnet information technology (IT) career academy compared to a traditional, comprehensive high school. We utilized propensity score matching to match academy and comprehensive high school learners on various demographic variables. The propensity score matching resulted in 299 matched pairs (n = 598). Using the matched groups, we ran linear regression models to investigate the relationship between school participation and students’ perceptions of their 21^st-Century skill attainment. We found that …

A Survey Of Faculty Perceptions Of Community College Career And Technical Education, Thomas Gauthier Dr.

Journal of Research in Technical Careers

Community colleges are the leaders in facilitating career and technical education (CTE), and faculty help develop program offerings on campus. This study explored faculty perceptions of community college CTE programs using the survey research method. Participants included 36 faculty members from various disciplines from 15 state colleges in Florida. Participants were sent a digital survey and asked to use a scale from 0 (do not agree) to 8 (agree) to score their agreement level with 43 statements of opinion. Data revealed that community college faculty perceive CTE as beneficial, but CTE programs must include the habits of mind and support …

Numerical Modeling Of Mineralizing Processes During The Formation Of The Yangzhuang Kiruna-Type Iron Deposit, Middle And Lower Yangtze River Metallogenic Belt, China: Implications For The Genesis And Longevity Of Kiruna-Type Iron Oxide-Apatite Systems, Xunyu Hu, Simon Jowitt, Feng Yuan, Guangxian Liu, Jinhui Luo, Yuhua Chen, Hui Yang, Keyue Ren, Yongguo Yang

Geoscience Faculty Research

The Yangzhuang iron deposit is a Kiruna-type iron oxide-apatite (IOA) deposit within the Ningwu mining district of the Middle and Lower Yangtze River Metallogenic Belt (MLYRMB), China. This study applies a numerical modeling approach to identify the key processes associated with the formation of the deposit that cannot be easily identified using traditional analytical approaches, including the duration of the mineralizing process and the genesis of iron orebodies within intrusions associated with the deposit. This approach highlights the practical value of numerical modeling in quantitatively analyzing mineralizing processes during the formation of mineral deposits and assesses how these methods can …

Eccentric Neutron Star Disk Driven Type Ii Outburst Pairs In Be/X-Ray Binaries, Alessia Franchini, Rebecca G. Martin

Physics & Astronomy Faculty Research

Be star X-ray binaries are transient systems that show two different types of outbursts. Type I outbursts occur each orbital period while type II outbursts have a period and duration that are not related to any periodicity of the binary system. Type II outbursts may be caused by mass transfer to the neutron star from a highly eccentric Be star disk. A sufficiently misaligned Be star decretion disk undergoes secular Von Zeipel-Lidov-Kozai (ZLK) oscillations of eccentricity and inclination. Observations show that in some systems the type II outbursts come in pairs with the second being of lower luminosity. We use …

Machine Learning And Radiomic Features To Predict Overall Survival Time For Glioblastoma Patients, Lina Chato, Shahram Latifi

Electrical & Computer Engineering Faculty Research

Glioblastoma is an aggressive brain tumor with a low survival rate. Understanding tumor behavior by predicting prognosis outcomes is a crucial factor in deciding a proper treatment plan. In this paper, an automatic overall survival time prediction system (OST) for glioblastoma patients is developed on the basis of radiomic features and machine learning (ML). This system is designed to predict prognosis outcomes by classifying a glioblastoma patient into one of three survival groups: short-term, mid-term, and long-term. To develop the prediction system, a medical dataset based on imaging information from magnetic resonance imaging (MRI) and non-imaging information is used. A …