Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Nevada, Las Vegas

Series

2020

Discipline
Keyword
Publication

Articles 1 - 30 of 82

Full-Text Articles in Physical Sciences and Mathematics

Pyxtal_Ff: A Python Library For Automated Force Field Generation, Howard Yanxon, David Zagaceta, Binh Tang, David S. Matteson, Qiang Zhu Dec 2020

Pyxtal_Ff: A Python Library For Automated Force Field Generation, Howard Yanxon, David Zagaceta, Binh Tang, David S. Matteson, Qiang Zhu

Physics & Astronomy Faculty Research

We present PyXtal_FF—a package based on Python programming language—for developing machine learning potentials (MLPs). The aim of PyXtal_FF is to promote the application of atomistic simulations through providing several choices of atom-centered descriptors and machine learning regressions in one platform. Based on the given choice of descriptors (including the atom-centered symmetry functions, embedded atom density, SO4 bispectrum, and smooth SO3 power spectrum), PyXtal_FF can train MLPs with either generalized linear regression or neural network models, by simultaneously minimizing the errors of energy/forces/stress tensors in comparison with the data from ab-initio simulations. The trained MLP model from PyXtal_FF is interfaced with …

Go to article

3d Numerical Simulation-Based Targeting Of Skarn Type Mineralization Within The Xuancheng-Magushan Orefield, Middle-Lower Yangtze Metallogenic Belt, China, Xunyu Hu, Xiaohui Li, Feng Yuan, Simon M. Jowitt, Alison Ord, Rui Ye, Yue Li, Wenqiang Dai, Xiangling Li Dec 2020

3d Numerical Simulation-Based Targeting Of Skarn Type Mineralization Within The Xuancheng-Magushan Orefield, Middle-Lower Yangtze Metallogenic Belt, China, Xunyu Hu, Xiaohui Li, Feng Yuan, Simon M. Jowitt, Alison Ord, Rui Ye, Yue Li, Wenqiang Dai, Xiangling Li

Geoscience Faculty Publications

Recent exploration has identified a series of Cu-Mo skarn deposits within the Xuancheng-Magushan orefield. The orefield forms part of the Nanling-Xuancheng mining district, which is located within the Middle-Lower Yangtze River Metallogenic Belt (MLYRMB) of central-eastern China. However, this area contains thick and widespread unprospective sedimentary cover sequences that have impeded traditional approaches to mineral exploration. This study presents the results of 3D numerical simulation modeling that identifies possible mineral exploration targets within the entire Xuancheng-Magushan orefield. This modeling enables the identification of unexplored areas with significant exploration potential that are covered by thick sedimentary sequences that cannot be easily …

Go to article

Two New Finite Element Schemes And Their Analysis For Modeling Of Wave Propagation In Graphene, Jichun Li Dec 2020

Two New Finite Element Schemes And Their Analysis For Modeling Of Wave Propagation In Graphene, Jichun Li

Mathematical Sciences Faculty Research

© 2020 The Author(s) In this paper, we investigate a system of governing equations for modeling wave propagation in graphene. Compared to our previous work (Yang et al., 2020), here we re-investigate the governing equations by eliminating two auxiliary unknowns from the original model. A totally new stability for the model is established for the first time. Since the finite element scheme proposed in Yang et al. (2020) is only first order in time, here we propose two new schemes with second order convergence in time for the simplified modeling equations. Discrete stabilities inheriting exactly the same form as the …

Go to article

Structure Analysis Of Natural Wangdaodeite—Linbo3-Type Fetio3, Oliver Tschauner, Chi Ma, Matthew G. Newville, Antonio Lanzirotti Dec 2020

Structure Analysis Of Natural Wangdaodeite—Linbo3-Type Fetio3, Oliver Tschauner, Chi Ma, Matthew G. Newville, Antonio Lanzirotti

Geoscience Faculty Publications

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper reports the first structure refinement of natural wangdaodeite, LiNbO3-type FeTiO3 from the Ries impact structure. Wangdaodeite occurs together with recrystallized ilmenite clasts in shock melt veins which have experienced peak shock pressures of between 17 and 22 GPa. Comparison of natural and synthetic wangdaodeite points toward a correlation between the distortion of ferrate-and titanate-polyhedra and the c/a ratio of the unit cell. The Raman spectrum of wangdaodeite is calculated based on the refined structure. Comparison to the reported spectrum of the type-material shows that the Raman peak at 738–740 …

Go to article

Response Of The Mode Grüneisen Parameters With Anisotropic Compression: A Pressure And Temperature Dependent Raman Study Of Β-Sn, Jasmine K. Hinton, Christian Childs, Dean Smith, Paul B. Ellison, Keith V. Lawler, Ashkan Salamat Nov 2020

Response Of The Mode Grüneisen Parameters With Anisotropic Compression: A Pressure And Temperature Dependent Raman Study Of Β-Sn, Jasmine K. Hinton, Christian Childs, Dean Smith, Paul B. Ellison, Keith V. Lawler, Ashkan Salamat

Physics & Astronomy Faculty Research

The lattice dynamic response of body-centered tetragonal β−Sn (I41/amd) under high pressure and -temperature conditions is determined using experimental optical vibration modes. Raman scattering is used to map the phase stability region of β−Sn to perform mode Grüneisen analysis, and we demonstrate the necessity of an optical intensity calibration for Raman thermometry. The Grüneisen tensor is evaluated along a set of isotherms to address shortcomings of single-mode Grüneisen parameters with respect to anisotropic deformations of this tetragonal structured soft metal. The changes observed here in the Grüneisen tensor as a function of temperature are related to anharmonicity and denote potential …

Go to article

What Martian Meteorites Reveal About The Interior And Surface Of Mars, Arya Udry, G. H. Howarth, C. D.K. Herd, J. M.D. Day, T. J. Lapen, J. Filiberto Nov 2020

What Martian Meteorites Reveal About The Interior And Surface Of Mars, Arya Udry, G. H. Howarth, C. D.K. Herd, J. M.D. Day, T. J. Lapen, J. Filiberto

Geoscience Faculty Publications

Martian meteorites are the only direct samples from Mars, thus far. Currently, there are a total of 262 individual samples originating from at least 11 ejection events. Geochemical analyses, through techniques that are also used on terrestrial rocks, provide fundamental insights into the bulk composition, differentiation and evolution, mantle heterogeneity, and role of secondary processes, such as aqueous alteration and shock, on Mars. Martian meteorites display a wide range in mineralogy and chemistry, but are predominantly basaltic in composition. Over the past 6 years, the number of martian meteorites recovered has almost doubled allowing for studies that evaluate these meteorites …

Go to article

Potential Application Of Ionic Liquids For Electrodeposition Of The Material Targets For Production Of Diagnostic Radioisotopes, Maciej Chotkowski, Damian Połomski, Kenneth Czerwinski Nov 2020

Potential Application Of Ionic Liquids For Electrodeposition Of The Material Targets For Production Of Diagnostic Radioisotopes, Maciej Chotkowski, Damian Połomski, Kenneth Czerwinski

Chemistry and Biochemistry Faculty Research

An overview of the reported electrochemistry studies on the chemistry of the element for targets for isotope production in ionic liquids (ILs) is provided. The majority of investigations have been dedicated to two aspects of the reactive element chemistry. The first part of this review presents description of the cyclotron targets properties, especially physicochemical characterization of irradiated elements. The second part is devoted to description of the electrodeposition procedures leading to obtain elements or their alloys coatings (e.g., nickel, uranium) as the targets for cyclotron and reactor generation of the radioisotopes. This review provides an evaluation of the role ILs …

Go to article

The Evolution Of A Circumplanetary Disc With A Dead Zone, Cheng Chen, Chao Chin Yang, Rebecca G. Martin, Zhaohuan Zhu Nov 2020

The Evolution Of A Circumplanetary Disc With A Dead Zone, Cheng Chen, Chao Chin Yang, Rebecca G. Martin, Zhaohuan Zhu

Physics & Astronomy Faculty Research

© 2021 Oxford University Press. All rights reserved. We investigate whether the regular Galilean satellites could have formed in the dead zone of a circumplanetary disc. A dead zone is a region of weak turbulence in which the magnetorotational instability is suppressed, potentially an ideal environment for satellite formation. With the grid-based hydrodynamic code FARGO3D, we examine the evolution of a circumplanetary disc model with a dead zone. Material accumulates in the dead zone of the disc leading to a higher total mass and but a similar temperature profile compared to a fully turbulent disc model. The tidal torque increases …

Go to article

Lead Complexation By Humic Acids And Their Analogs: A Voltammetric Study, Spencer Steinberg, Vernon Hodge Nov 2020

Lead Complexation By Humic Acids And Their Analogs: A Voltammetric Study, Spencer Steinberg, Vernon Hodge

Chemistry and Biochemistry Faculty Research

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Differential pulse polarography (DPP) was used to assess the interaction of Pb2+ with various humic acid analogs and several humic acids. DPP analysis demonstrated that the reduction peak maximum (Ep) for Pb2+ shifted to more negative values in the presence of humic acids and humic acid analogs. The observed Ep for Pb2+ in the presence of humic acids and humic acid analogs is influenced by ligand concentration, solution pH and Pb2+ concentration. Shifts in the Ep for Pb2+ are related to the reduction potential and can be rationalized using the Lingane …

Go to article

Radiological Identification Of Near‐Surface Mineralogical Deposits Using Low‐Altitude Unmanned Aerial Vehicle, Peter G. Martin, Dean T. Connor, Natalia Estrada, Adel El-Turke, David Megson-Smith, Chris P. Jones, David K. Kreamer, Thomas B. Scott Oct 2020

Radiological Identification Of Near‐Surface Mineralogical Deposits Using Low‐Altitude Unmanned Aerial Vehicle, Peter G. Martin, Dean T. Connor, Natalia Estrada, Adel El-Turke, David Megson-Smith, Chris P. Jones, David K. Kreamer, Thomas B. Scott

Geoscience Faculty Publications

An ever‐increasing global population and unabating technological growth have resulted in a relentless appetite for mineral resources, namely rare earth elements, fuel minerals and those utilised in electronics applications, with the price of such species continuing to climb. In contrast to more established large‐scale and high‐cost exploration methodologies, this work details the application of novel multi‐rotor unmanned aerial vehicles equipped with miniaturised radiation detectors for the objective of undertaking resource exploration at lower costs, with greater autonomy and at considerably enhanced higher spatial resolutions; utilizing the ore material’s inherent low levels of characteristic radioactivity. As we demonstrate at the former …

Go to article

Xenon Iron Oxides Predicted As Potential Xe Hosts In Earth’S Lower Mantle, Feng Peng, Xianqi Song, Chang Liu, Quan Li, Maosheng Miao, Changfeng Chen, Yanming Ma Oct 2020

Xenon Iron Oxides Predicted As Potential Xe Hosts In Earth’S Lower Mantle, Feng Peng, Xianqi Song, Chang Liu, Quan Li, Maosheng Miao, Changfeng Chen, Yanming Ma

Physics & Astronomy Faculty Research

An enduring geological mystery concerns the missing xenon problem, referring to the abnormally low concentration of xenon compared to other noble gases in Earth’s atmosphere. Identifying mantle minerals that can capture and stabilize xenon has been a great challenge in materials physics and xenon chemistry. Here, using an advanced crystal structure search algorithm in conjunction with first-principles calculations we find reactions of xenon with recently discovered iron peroxide FeO2, forming robust xenon-iron oxides Xe2FeO2 and XeFe3O6 with significant Xe-O bonding in a wide range of pressure-temperature conditions corresponding to vast regions in Earth’s lower mantle. Calculated mass density and sound …

Go to article

Countercurrent Actinide Lanthanide Separation Process (Alsep) Demonstration Test With A Simulated Purex Raffinate In Centrifugal Contactors On The Laboratory Scale, Andreas Wilden, Fabian Kreft, Dimitri Schneider, Zaina Paparigas, Giuseppe Modolo, Gregg J. Lumetta, Artem V. Gelis, Jack D. Law, Andreas Geist Oct 2020

Countercurrent Actinide Lanthanide Separation Process (Alsep) Demonstration Test With A Simulated Purex Raffinate In Centrifugal Contactors On The Laboratory Scale, Andreas Wilden, Fabian Kreft, Dimitri Schneider, Zaina Paparigas, Giuseppe Modolo, Gregg J. Lumetta, Artem V. Gelis, Jack D. Law, Andreas Geist

Chemistry and Biochemistry Faculty Research

An Actinide Lanthanide Separation Process (ALSEP) for the separation of trivalent actinides (An(III)) from simulated raffinate solution was successfully demonstrated using a 32-stage 1 cm annular centrifugal contactor setup. The ALSEP solvent was composed of a mixture of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and N,N,N′,N′-tetra-(2-ethylhexyl)-diglycolamide (T2EHDGA) in n-dodecane. Flowsheet calculations and evaluation of the results were done using the Argonne’s Model for Universal Solvent Extraction (AMUSE) code using single-stage distribution data. The co-extraction of Zr(IV) and Pd(II) was prevented using CDTA (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid) as a masking agent in the feed. For the scrubbing of co-extracted Mo; citrate-buffered acetohydroxamic acid was …

Go to article

Toughening A Superstrong Carbon Crystal: Sequential Bond-Breaking Mechanisms, Hui Liang, Hefei Li, Quan Li, Changfeng Chen Oct 2020

Toughening A Superstrong Carbon Crystal: Sequential Bond-Breaking Mechanisms, Hui Liang, Hefei Li, Quan Li, Changfeng Chen

Physics & Astronomy Faculty Research

A complex orthorhombic carbon allotrope in Pbam symmetry with 32 atoms in its unit cell, thus termed Pbam-32 carbon, was recently predicted [C. Y. He et al., Phys. Rev. Lett. 121, 175701 (2018)]. Its crystal structure comprises alternating fivefold, sixfold, and sevenfold carbon rings and exhibits reduced bonding anisotropy compared to diamond, raising the prospects of finding a superstrong material with distinct and favorable mechanical properties. Here we report findings from first-principles calculations that reveal peculiar stress-strain relations in Pbam-32 carbon. The obtained stress responses under various tensile and shear strains display outstanding characteristics contrasting those of traditional superhard materials …

Go to article

Recent Advancements In The Removal Of Cyanotoxins From Water Using Conventional And Modified Adsorbents—A Contemporary Review, Tauqeer Abbas, George William Kajjumba, Meena Ejjada, Sayeda Ummeh Masrura, Erica J. Marti, Eakalak Khan, Tammy L. Jones-Lepp Oct 2020

Recent Advancements In The Removal Of Cyanotoxins From Water Using Conventional And Modified Adsorbents—A Contemporary Review, Tauqeer Abbas, George William Kajjumba, Meena Ejjada, Sayeda Ummeh Masrura, Erica J. Marti, Eakalak Khan, Tammy L. Jones-Lepp

Civil and Environmental Engineering and Construction Faculty Research

The prevalence of cyanobacteria is increasing in freshwaters due to climate change, eutrophication, and their ability to adapt and thrive in changing environmental conditions. In response to various environmental pressures, they produce toxins known as cyanotoxins, which impair water quality significantly. Prolonged human exposure to cyanotoxins, such as microcystins, cylindrospermopsin, saxitoxins, and anatoxin through drinking water can cause severe health effects. Conventional water treatment processes are not effective in removing these cyanotoxins in water and advanced water treatment processes are often used instead. Among the advanced water treatment methods, adsorption is advantageous compared to other methods because of its affordability …

Go to article

Rethinking The Weakness Of Stream Ciphers And Its Application To Encrypted Malware Detection, William Stone, Daeyoung Kim, Victor Youdom Kemmoe, Mingon Kang, Junggab Son Oct 2020

Rethinking The Weakness Of Stream Ciphers And Its Application To Encrypted Malware Detection, William Stone, Daeyoung Kim, Victor Youdom Kemmoe, Mingon Kang, Junggab Son

Computer Science Faculty Research

One critical vulnerability of stream ciphers is the reuse of an encryption key. Since most stream ciphers consist of only a key scheduling algorithm and an Exclusive OR (XOR) operation, an adversary may break the cipher by XORing two captured ciphertexts generated under the same key. Various cryptanalysis techniques based on this property have been introduced in order to recover plaintexts or encryption keys; in contrast, this research reinterprets the vulnerability as a method of detecting stream ciphers from the ciphertexts it generates. Patterns found in the values (characters) expressed across the bytes of a ciphertext make the ciphertext distinguishable …

Go to article

Pressure-Stabilized Divalent Ozonide Cao3 And Its Impact On Earth’S Oxygen Cycles, Yanchao Wang, Meiling Xu, Liuxiang Yang, Bingmin Yan, Qin Qin, Xuecheng Shao, Yunwei Zhang, Dajian Huang, Xiaohuan Lin, Jian Lv, Dongzhou Zhang, Huiyang Gou, Ho-Kwang Mao, Changfeng Chen, Yanming Ma Sep 2020

Pressure-Stabilized Divalent Ozonide Cao3 And Its Impact On Earth’S Oxygen Cycles, Yanchao Wang, Meiling Xu, Liuxiang Yang, Bingmin Yan, Qin Qin, Xuecheng Shao, Yunwei Zhang, Dajian Huang, Xiaohuan Lin, Jian Lv, Dongzhou Zhang, Huiyang Gou, Ho-Kwang Mao, Changfeng Chen, Yanming Ma

Physics & Astronomy Faculty Research

High pressure can drastically alter chemical bonding and produce exotic compounds that defy conventional wisdom. Especially significant are compounds pertaining to oxygen cycles inside Earth, which hold key to understanding major geological events that impact the environment essential to life on Earth. Here we report the discovery of pressure-stabilized divalent ozonide CaO3 crystal that exhibits intriguing bonding and oxidation states with profound geological implications. Our computational study identifies a crystalline phase of CaO3 by reaction of CaO and O2 at high pressure and high temperature conditions; ensuing experiments synthesize this rare compound under compression in a diamond anvil cell with …

Go to article

Resilience And Alternative Stable States After Desert Wildfires, Scott R. Abella, Dominic M. Gentilcore, Lindsay P. Chiquoine Sep 2020

Resilience And Alternative Stable States After Desert Wildfires, Scott R. Abella, Dominic M. Gentilcore, Lindsay P. Chiquoine

Life Sciences Faculty Research

Improving models of community change is a fundamental goal in ecology and has renewed importance during global change and increasing human disturbance of the biosphere. Using the Mojave Desert (southwestern United States) as a model system, invaded by nonnative plants and subject to wildfire disturbances, we examined models of resilience, alternative stable states, and convergent-divergent trajectories for 36 yr of plant community change after 31 wildfires in communities dominated by the native shrubs Larrea tridentata or Coleogyne ramosissima. Perennial species richness on average was fully resilient within 23 yr after disturbance in both community types. Perennial cover was fully resilient …

Go to article

Investigation Of The Interaction Of Gadolinium With Several Organic Ligands And Humic Acid By Ligand Competition Using 4-(2-Pyridylazo)-Resorcinol (Par), Spencer Steinberg, Vernon Hodge, Luis Becerra-Hernandez Sep 2020

Investigation Of The Interaction Of Gadolinium With Several Organic Ligands And Humic Acid By Ligand Competition Using 4-(2-Pyridylazo)-Resorcinol (Par), Spencer Steinberg, Vernon Hodge, Luis Becerra-Hernandez

Chemistry and Biochemistry Faculty Research

Gd3+ forms a strongly colored complex with 4-(2-pyridylazo)-resorcinol (PAR) in aqueous solutions. We characterized the Gd3+-PAR complex in order to use it as a probe of Gd3+ speciation in the presence of environmentally relevant ligands. The formation of the Gd3+-PAR complex was investigated from pH 5 to 8 in the presence of excess PAR. The absorbance of the Gd3+-PAR complex dramatically increased from pH 5 to 8 and application of the method of continuous variation indicates that the complex was primarily 1:2 Gd(PAR)2 at pH 8. Stability constants for Gd3+ with other ligands can be quantified by competitive displacement of …

Go to article

Future Availability Of Non-Renewable Metal Resources And The Influence Of Environmental, Social, And Governance Conflicts On Metal Production, Simon Jowitt, Gavin M. Mudd, John F.H. Thompson Sep 2020

Future Availability Of Non-Renewable Metal Resources And The Influence Of Environmental, Social, And Governance Conflicts On Metal Production, Simon Jowitt, Gavin M. Mudd, John F.H. Thompson

Geoscience Faculty Publications

Metal mining provides the elements required for the provision of energy, communication, transport and more. The increasing uptake of green technology, such as electric vehicles and renewable energy, will also further increase metal demand. However, the production lifespan of an average mine is far shorter than the timescales of mineral deposit formation, suggesting that metal mining is unsustainable on human timescales. In addition, some research suggests that known primary metal supplies will be exhausted within about 50 years. Here we present an analysis of global metal reserves that suggests that primary metal supplies will not run out on this timescale. …

Go to article

Measuring The Perceived Social Intelligence Of Robots, Kimberly A. Barchard, Leiszle Lapping-Carr, R. Shane Westfall, Andrea Fink-Armold, Santosh Balajee Banisetty, David Feil-Seifer Sep 2020

Measuring The Perceived Social Intelligence Of Robots, Kimberly A. Barchard, Leiszle Lapping-Carr, R. Shane Westfall, Andrea Fink-Armold, Santosh Balajee Banisetty, David Feil-Seifer

Psychology Faculty Research

Robotic social intelligence is increasingly important. However, measures of human social intelligence omit basic skills, and robot-specific scales do not focus on social intelligence. We combined human robot interaction concepts of beliefs, desires, and intentions with psychology concepts of behaviors, cognitions, and emotions to create 20 Perceived Social Intelligence (PSI) Scales to comprehensively measure perceptions of robots with a wide range of embodiments and behaviors. Participants rated humanoid and non-humanoid robots interacting with people in five videos. Each scale had one factor and high internal consistency, indicating each measures a coherent construct. Scales capturing perceived social information processing skills (appearing …

Go to article

Machine Learning Corrected Quantum Dynamics Calculations, A. Jasinski, J. Montaner, R. C. Forrey, B. H. Yang, P. C. Stancil, Naduvalath Balakrishnan, J. Dai, A. Vargas-Hernandez, R. V. Krems Aug 2020

Machine Learning Corrected Quantum Dynamics Calculations, A. Jasinski, J. Montaner, R. C. Forrey, B. H. Yang, P. C. Stancil, Naduvalath Balakrishnan, J. Dai, A. Vargas-Hernandez, R. V. Krems

Chemistry and Biochemistry Faculty Research

Quantum scattering calculations for all but low-dimensional systems at low energies must rely on approximations. All approximations introduce errors. The impact of these errors is often difficult to assess because they depend on the Hamiltonian parameters and the particular observable under study. Here, we illustrate a general, system- and approximation-independent, approach to improve the accuracy of quantum dynamics approximations. The method is based on a Bayesian machine learning (BML) algorithm that is trained by a small number of exact results and a large number of approximate calculations, resulting in ML models that can generalize exact quantum results to different dynamical …

Go to article

Late Quaternary Climate Variability And Change From Aotearoa New Zealand Speleothems: Progress In Age Modelling, Oxygen Isotope Master Record Construction And Proxy-Model Comparisons, Andrew M. Lorrey, Paul W. Williams, John-Mark Woolley, Nicolas C. Faushereau, Adam Hartland, Helen Bostock, Shaun Eaves, Matthew S. Lachniet, James A. Renwick, Vidya Varma Aug 2020

Late Quaternary Climate Variability And Change From Aotearoa New Zealand Speleothems: Progress In Age Modelling, Oxygen Isotope Master Record Construction And Proxy-Model Comparisons, Andrew M. Lorrey, Paul W. Williams, John-Mark Woolley, Nicolas C. Faushereau, Adam Hartland, Helen Bostock, Shaun Eaves, Matthew S. Lachniet, James A. Renwick, Vidya Varma

Geoscience Faculty Publications

We re-evaluated speleothem isotope series from Aotearoa New Zealand that were recently contributed to the Speleothem Isotopes Synthesis and AnaLysis (SISAL) database. COnstructing Proxy Records from Age Models (COPRA) software was used to produce Bayesian age models for those speleothems. The new age modelling helped us examine Late Quaternary temporal coverage for the national speleothem network, and also supported our exploration of three different isotope master record generation techniques using Holocene δ18O data from Waitomo. We then applied the output from one of the isotope master record techniques to test an application case of how climate transfer functions can be …

Go to article

Tricyclic Antidepressant Use And Risk Of Fractures: A Meta-Analysis Of Cohort Studies Through The Use Of Both Frequentist And Bayesian Approaches, Qing Wu, Yingke Xu, Yueyang Bao, Jovan Alvarez, Mikee Lianne Gonzales Aug 2020

Tricyclic Antidepressant Use And Risk Of Fractures: A Meta-Analysis Of Cohort Studies Through The Use Of Both Frequentist And Bayesian Approaches, Qing Wu, Yingke Xu, Yueyang Bao, Jovan Alvarez, Mikee Lianne Gonzales

School of Medicine Faculty Publications

Background: Research findings regarding the association between tricyclic antidepressant (TCA) treatment and the risk of fracture are not consistent; we aimed to assess whether people who take TCAs are at an increased fracture risk. Methods: Relevant studies published through June 2020 were identified through database searches of MEDLINE, EMBASE, Scopus, PsycINFO, ISI Web of Science, WorldCat Dissertations and Theses from each database’s inception, as well as through manual searches of relevant reference lists. Two researchers independently performed literature searches, study selection, data abstraction and study appraisal by using a standardized protocol. Frequentist and Bayesian hierarchical random-effects models were used for …

Go to article

Interplay Of Trna-Derived Fragments And T Cell Activation In Breast Cancer Patient Survival, Nayang Shan, Ningshan Li, Qile Dai, Lin Hou, Xiting Yan, Amei Amei, Lingeng Lu, Zuoheng Wang Aug 2020

Interplay Of Trna-Derived Fragments And T Cell Activation In Breast Cancer Patient Survival, Nayang Shan, Ningshan Li, Qile Dai, Lin Hou, Xiting Yan, Amei Amei, Lingeng Lu, Zuoheng Wang

Mathematical Sciences Faculty Research

Effector CD8+ T cell activation and its cytotoxic function are positively correlated with improved survival in breast cancer. tRNA-derived fragments (tRFs) have recently been found to be involved in gene regulation in cancer progression. However, it is unclear how interactions between expression of tRFs and T cell activation affect breast cancer patient survival. We used Kaplan–Meier survival and multivariate Cox regression models to evaluate the effect of interactions between expression of tRFs and T cell activation on survival in 1081 breast cancer patients. Spearman correlation analysis and weighted gene co-expression network analysis were conducted to identify genes and pathways that …

Go to article

Probing The Intergalactic Turbulence With Fast Radio Bursts, Siyao Xu, Bing Zhang Jul 2020

Probing The Intergalactic Turbulence With Fast Radio Bursts, Siyao Xu, Bing Zhang

Physics & Astronomy Faculty Research

The turbulence in the diffuse intergalactic medium (IGM) plays an important role in various astrophysical processes across cosmic time, but it is very challenging to constrain its statistical properties both observationally and numerically. Via the statistical analysis of turbulence along different sight lines toward a population of fast radio bursts (FRBs), we demonstrate that FRBs provide a unique tool to probe the intergalactic turbulence. We measure the structure function (SF) of dispersion measures (DMs) of FRBs to study the multiscale electron density fluctuations induced by the intergalactic turbulence. The SF has a large amplitude and a Kolmogorov power-law scaling with …

Go to article

Utility Of Inflammatory Markers To Predict Adverse Outcome In Acute Pancreatitis: A Retrospective Study In A Single Academic Center, Mohamad Mubder, Banreet Dhindsa, Danny Nguyen, Syed Saghir, Chad Cross, Ranjit Makar, Gordon Ohning Jul 2020

Utility Of Inflammatory Markers To Predict Adverse Outcome In Acute Pancreatitis: A Retrospective Study In A Single Academic Center, Mohamad Mubder, Banreet Dhindsa, Danny Nguyen, Syed Saghir, Chad Cross, Ranjit Makar, Gordon Ohning

School of Medicine Faculty Publications

Background/Aim: Acute pancreatitis (AP) is a commonly encountered emergency where early identification of complicated cases is important. Inflammatory markers like lymphocyte to monocyte ratio (LMR) and neutrophil to lymphocyte ratio (NLR) are simple and readily available markers. In this study, we evaluated the utility of these markers in the early identification of patients with complicated AP. Patients and Methods: All patients with a diagnosis of AP admitted to the University Medical Center in Las Vegas/Nevada between August 2015 and September 2018 were identified using ICD-10 codes. Medical records were reviewed retrospectively. Epidemiological measures and their associated confidence intervals were calculated …

Go to article

Chemist Table: A Tool For Designing Or Modifying Instruction For A Systems Thinking Approach In Chemistry Education, Sarah York, Marykay Orgill Jul 2020

Chemist Table: A Tool For Designing Or Modifying Instruction For A Systems Thinking Approach In Chemistry Education, Sarah York, Marykay Orgill

Chemistry and Biochemistry Faculty Research

Recently, there have been calls to integrate systems thinking approaches into chemistry education in order to strengthen students’ conceptual understanding, build their problem-solving capabilities, and prepare them to make informed, ethical decisions about globally relevant issues, such as sustainability. Unfortunately, implementation of systems thinking approaches in chemistry classrooms currently poses challenges. Exemplar systems thinking materials with a STEM focus are limited, particularly at the tertiary level. Moreover, the science education community has yet to agree upon a systems thinking definition or develop a comprehensive list of systems thinking skills that students should develop. Thus, a current priority for the advancement …

Go to article

Preservation Of Latest Cretaceous (Maastrichtian) - Paleocene Frogs (Eorubeta Nevadensis) Of The Sheep Pass Formation Of East-Central Nevada And Implications For Paleogeography Of The Nevadaplano, Joshua W. Bonde, Peter A. Druschke, Richard P. Hilton, Amy C. Henrici, Stephen M. Rowland Jul 2020

Preservation Of Latest Cretaceous (Maastrichtian) - Paleocene Frogs (Eorubeta Nevadensis) Of The Sheep Pass Formation Of East-Central Nevada And Implications For Paleogeography Of The Nevadaplano, Joshua W. Bonde, Peter A. Druschke, Richard P. Hilton, Amy C. Henrici, Stephen M. Rowland

Geoscience Faculty Publications

Here we report on exceptional preservation of remains of the frog Eorubeta nevadensis in deposits of the Sheep Pass Formation, ranging from Late Cretaceous to Eocene, in the south Egan Range, Nevada. This formation represents a lacustrine basin within the Sevier retroarc hinterland. The formation is subdivided into six members (A–F); of interest here are members B and C. The base of member B is ?uppermost Cretaceous-Paleocene, while member C is Paleocene. Member B frogs are preserved in three taphonomic modes. Mode 1 frogs are nearly complete and accumulated under attritional processes, with frogs settling on microbial mats, as evidenced …

Go to article

Design Aspects, Energy Consumption Evaluation, And Offset For Drinking Water Treatment Operation, Saria Bukhary, Jacimaria Batista, Sajjad Ahmad Jun 2020

Design Aspects, Energy Consumption Evaluation, And Offset For Drinking Water Treatment Operation, Saria Bukhary, Jacimaria Batista, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Drinking water treatment, wastewater treatment, and water distribution are energy-intensive processes. The goal of this study was to design the unit processes of an existing drinking water treatment plant (DWTP), evaluate the associated energy consumption, and then offset it using solar photovoltaics (PVs) to reduce carbon emissions. The selected DWTP, situated in the southwestern United States, utilizes coagulation, flocculation, sedimentation, filtration, and chlorination to treat 3.94 m3 of local river water per second. Based on the energy consumption determined for each unit process (validated using the plant’s data) and the plant’s available landholding, the DWTP was sized for solar PV …

Go to article

Great Basin Paleoclimate And Aridity Linked To Artic Warming And Tropical Pacific Sea Surface Temperature, Matthew S. Lachniet, Yemane Asmerom, Victor Polyak, Rhawn Denniston Jun 2020

Great Basin Paleoclimate And Aridity Linked To Artic Warming And Tropical Pacific Sea Surface Temperature, Matthew S. Lachniet, Yemane Asmerom, Victor Polyak, Rhawn Denniston

Geoscience Faculty Publications

The arid southwestern United States is susceptible to sustained droughts that impact water resources and economic activity for millions of residents. Previous work has not systematically investigated the structure, timing, and possible forcings of Holocene Great Basin sub‐orbital hydroclimate changes, impeding our ability to understand the potential future controls on Southwestern aridity. The objective of this paper is to constrain the potential forcings on Holocene aridity and temperature, via comparison of new high‐resolution speleothem data, an Aridity Index synthesizing hydroclimate records, and linkages of Southwestern paleoclimate to other regions. The high‐resolution data from Leviathan Cave provide a paleoclimate record since …

Go to article

Next Last