Physical Sciences and Mathematics Commons^™

Interactions Of (My) 6 (M = Zn, Cd; Y = O, S, Se) Quantum Dots With N-Bases, Mariusz Michalczyk, Wiktor Zierkiewicz, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

(MY)₆ clusters, with M = Zn and Cd and Y = O, S, Se, form double-layer drum-like structures containing M–Y covalent bonds. The positive regions near the M atoms attract the N atom of both NH₃ and NMe₃ so as to form a noncovalent M···N bond. This bond is quite strong, with interaction energies exceeding 35 kcal/mol. The bond strength diminishes with reduced electronegativity of the Y atom (O > S > Se) and is stronger for M = Zn than for Cd. Trimethylation of the base enhances the bond strength. The interaction is dominated by the electrostatic component …

Marine Reserves Shape Seascapes On Scales Visible From Space, Elizabeth M. P. Madin, Alastair R. Harborne, Aaron M. T. Harmer, Osmar J. Luiz, Trisha Brooke Atwood, Brian J. Sullivan, Joshua S. Madin

Watershed Sciences Faculty Publications

Marine reserves can effectively restore harvested populations, and ‘mega-reserves’ increasingly protect large tracts of ocean. However, no method exists of monitoring ecological responses at this large scale. Herbivory is a key mechanism structuring ecosystems, and this consumer–resource interaction's strength on coral reefs can indicate ecosystem health. We screened 1372, and measured features of 214, reefs throughout Australia's Great Barrier Reef using high-resolution satellite imagery, combined with remote underwater videography and assays on a subset, to quantify the prevalence, size and potential causes of ‘grazing halos’. Halos are known to be seascape-scale footprints of herbivory and other ecological interactions. Here we …

A Modeling Study Of The Responses Of Mesosphere And Lower Thermosphere Winds To Geomagnetic Storms At Middle Latitudes, Jingyuan Li, Wenbin Wang, Jianyong Lu, Jia Yue, Alan G. Burns, Tao Yuan, Xuetao Chen, Wenjun Dong

All Physics Faculty Publications

Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIMEGCM) simulations are diagnostically analyzed to investigate the causes of mesosphere and lower thermosphere (MLT) wind changes at middle latitudes during the 17 April 2002 storm. In the early phase of the storm, middle‐latitude upper thermospheric wind changes are greater and occur earlier than MLT wind changes. The horizontal wind changes cause downward vertical wind changes, which are transmitted to the MLT region. Adiabatic heating and heat advection associated with downward vertical winds cause MLT temperature increases. The pressure gradient produced by these temperature changes and the Coriolis force then drive strong equatorward …

The Nifz Accessory Protein Has An Equivalent Function In Maturation Of Both Nitrogenase Mofe Protein P-Clusters, Emilio Jimenez-Vicente, Zhi-Yong Yang, Julia S. Martin Del Campo, Valarie L. Cash, Lance C. Seefeldt, Dennis R. Dean

Chemistry and Biochemistry Faculty Publications

The Mo-dependent nitrogenase comprises two interacting components called the Fe protein and the MoFe protein. The MoFe protein is an α₂β₂ heterotetramer that harbors two types of complex metalloclusters, both of which are necessary for N₂reduction. One type is a 7Fe-9S-Mo-C-homocitrate species designated FeMo-cofactor, which provides the N₂-binding catalytic site, and the other is an 8Fe-7S species designated the P-cluster, involved in mediating intercomponent electron transfer to FeMo-cofactor. The MoFe protein's catalytic partner, Fe protein, is also required for both FeMo-cofactor formation and the conversion of an immature form of P-clusters to the …

Increased Variability Of Thailand's Chao Phraya River Peak Season Flow And Its Association With Enso Variability: Evidence From Tree Ring Δ18O, Chenxi Xu, Brendan M. Buckley, Parichart Promchote, S.-Y. Simon Wang, Nathsuda Pumijumnong, Wenling An, Masaki Sano, Takeshi Nakatsuka, Zhengtang Guo

Plants, Soils, and Climate Faculty Publications

We present a statistically robust reconstruction of Thailand's Chao Phraya River peak season streamflow (CPRPF) that spans the 202 years from 1804 to 2005 CE. Our reconstruction is based on tree ring δ¹⁸O series derived from three Pinus merkusii sites from Laos and Thailand. The regional δ¹⁸O index accounts for 57% of the observed variance of CPRPF. Spatial correlation and 21‐year running correlation analyses reveal that CPRPF is greatly influenced by regional precipitation variations associated with the El Niño–Southern Oscillation (ENSO). Periods of enhanced and reduced ENSO activity are associated with strong and weak ENSO‐streamflow correlation, …

Porting Symbolic Libraries From Maple To Python, James Lewis

Physics Capstone Projects

Utah State University has a database of tables of the known solutions of the Einstein Field Equation. This database is primarily recorded in the symbolic computing program Maple. This database needs to be translated into Python code so the information can be more accessible to the general public. This translation was successful for one table, which means that it is possible to translate the entire database.

Hydrated Sulfate Clusters So42–(H2o)N (N = 1–40): Charge Distribution Through Solvation Shells And Stabilization, Maksim Kulichenko, Nikita Fedik, Konstantin V. Bozhenko, Alexander I. Boldyrev

Chemistry and Biochemistry Faculty Publications

Investigations of inorganic anion SO₄^2– interactions with water are crucial for understanding the chemistry of its aqueous solutions. It is known that the isolated SO₄^2– dianion is unstable, and three H₂O molecules are required for its stabilization. In the current work, we report our computational study of hydrated sulfate clusters SO₄^2–(H₂O)_n (n = 1–40) in order to understand the nature of stabilization of this important anion by water molecules. We showed that the most significant charge transfer from dianion SO₄^2– to H₂O takes …

On The Capability Of Metal-Halogen Groups To Participate In Halogen Bonds, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

A number of halogen (X) atoms were covalently attached to a metal (M) and the ability of the X atom to act as electron acceptor in a halogen bond to nucleophile NCH was assessed. Both Cl and Br were considered as halogen atom, with NH3 and CO as other ligands attached to the metal. Metals tested were Ti, Mn, and Zn in various combinations of oxidation state, coordination, and overall charge. In the majority of cases, the strong electron-releasing power of the metal imbues the halogen atom with a high negative partial charge and minimizes the development of a σ-hole. …

On The Long Lasting “C‐Type” Structures In The Sodium Lidargram: The Lifetime Of Kelvin‐Helmholtz Billows In The Mesosphere And Lower Thermosphere Region, S. Mondal, S. Sarkhel, Jay Agarwal, D. Chakrabarty, R. Sekar, Tao Yuan, Xuguang Cai, Alan Z. Liu, Satonori Nozawa, Norihito Saito, Takuya D. Kawahara, Martin G. Mlynczak, James M. Russell Iii

All Physics Faculty Publications

In order to understand the characteristics of long‐lasting “C‐type” structure in the Sodium (Na) lidargram, six cases from different observational locations have been analyzed. The Na lidargram, collected from low‐, middle‐, and high‐latitude sites, show long lifetime of the C‐type structures which is believed to be the manifestation of Kelvin‐Helmholtz (KH) billows in the Mesosphere and Lower Thermosphere (MLT) region. In order to explore the characteristics of the long‐lasting C‐type structures, the altitude profile of square of Brunt‐Väisälä frequency in the MLT region has been derived using the temperature profile collected from the Na lidar instruments and the SABER instrument …

The Gear Up Experience: What Leads To College?, Erik Dickamore

Student Research Symposium

Gear up is a 6-year federal grant whose purpose is to encourage and support underprivileged students to enroll in and succeed in higher education. Gear up was deployed in 11 school districts across the state 5 and 1/2 years ago. Ambiguity arises when trying to assess the Gear Up program as a whole because each student's experience within the program varies. My research focuses on using advanced statistical techniques ie. a latent profile analysis (LPA) to look at the holistic experience of Gear Up Students. Results highlight the link between different profiles of experiences within the Gear Up program and …

The Effects Of Radiation-Induced Defects On The Electrostatic Discharge Of Polymers, Kip Quilter, Alexandra Hughlett

Student Research Symposium

Test were done to see how radiation-induced defect states affect the electrostatic discharge (ESD) breakdown potential of a material. We selected five different highly disorder polymers (PEEK, PI, FEP, PP, LDEP) due to their different tolerances to radiation. By irradiating samples with 5kGy of penetrating beta radiation in vacuo, we created more localized trap states in the polymers; this is known to increase hopping conductivity. It has also been hypothesized that post-irradiation exposure to oxygen or water in air can repair these defects. ESD can be viewed as an extreme limit of conductivity and therefore is expected to decrease as …

Climate Change At Utah Ski Resorts: Impacts, Perceptions, And Adaptation Strategies, Emily Wilkins, Tara Saley, Hadia Akbar, Rachel Hager

Student Research Symposium

Utah sees over four million skier visits per season, which has substantial economic impact across the state. However, climate change may affect the operability of these ski resorts, which could also impact local businesses and communities. With warming temperatures and changes in precipitation patterns, the future of Utah's ski resort industry may be uncertain. We conducted an interdisciplinary study to understand how past weather has changed at the resorts and what climate may be like in the future. We studied this using publically available weather data from PRISM, Daymet, and the National Snow and Ice Data Center, and climate change …

Gravitational Anomalies & Elliptic Curves, Michael T. Schultz

Student Research Symposium

A gravitational anomaly is a special type of curvature that is important in string theory. Elliptic curves are very important and ubiquitous in mathematics - for example, it was a special property of some families of elliptic curves that was instrumental in proving the famous Fermat's Last Theorem. In the context of my research, an elliptic curve is a torus defined by a simple polynomial equation. My research shows that every suitably general one parameter family of elliptic curves (called an elliptic fibration with section) has both local and global gravitational anomalies. In my talk, I will explain these anomalies …

Quaternions, Octonions, And Electromagnetism, Ben Shaw

Student Research Symposium

An introduction to Quaternions and Octonions is given, and the Maxwell Equations are formulated in terms of each. The conventional, source-free relativistic theory of eight dimensional electromagnetism is introduced and examined. Similarly, the source-free Octonionic Maxwell Equations are developed, and it is shown that the seven dimensional electric and magnetic fields pure Octonions each admit plane wave solutions. An Octonionic Faraday tensor is constructed and compared with the conventional Faraday tensor, and it is shown that, in the source-free case, the conventional and Octonionic theories are equivalent.

Temperature-Dependent Conductivity Of Highly Insulating Polymers, Megan Loveland, Brian Wood

Student Research Symposium

Temperature-dependent electrical conductivity measurements of polymers are compared to predictions by thermally assisted hopping conductivity, commonly used to model electron transport between defect sites in highly disordered insulating materials (HDIM). Constant voltage is applied across samples using a parallel plate geometry under vacuum, with the resulting current measured using a high resolution electrometer to calculate extreme low level conductivity. Conductivity of thin film PEEK (polyether ether ketone) and LDPE (low density polyethylene) samples was measured at temperatures ranging from 270 to 350 K to determine temperature influence on conductivity. Long time scales are needed for polymers to reach electrostatic equilibrium …

Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai

Plants, Soils, and Climate Faculty Publications

Spirea (Spiraea sp.) plants are commonly used in landscapes in Utah and the intermountain western United States. The relative salt tolerance of seven japanese spirea (Spiraea japonica) cultivars (Galen, Minspi, NCSX1, NCSX2, SMNSJMFP, Tracy, and Yan) were evaluated in a greenhouse. Plants were irrigated with a nutrient solution with an electrical conductivity (EC) of 1.2 dSmL1 (control) or saline solutions with an EC of 3.0 or 6.0 dSmL1 once per week for 8 weeks. At 8 weeks after the initiation of treatment, all japanese spirea cultivars irrigated with saline solution with an EC of 3.0 dSmL1 still exhibited good or …

Thermodynamic Properties Of Black Holes, Geoffrey Schulthess

Physics Capstone Projects

Black Holes are some of the most mysterious objects in the known universe. In 1975, Stephen Hawking stated that Black Holes can behave as thermodynamical objects with a finite mass, spin, angular velocity, temperature, and entropy. This has been one of the most fascinating yet perplexing breakthroughs in our understanding of these strongly gravitating objects. In this context, the purpose of this research was to use Wolfram Mathematica to create a program that would calculate the thermodynamic properties of a black hole, given a certain metric.

Physics 4900, David Maughan

Physics Capstone Projects

More than a century has passed since Albert Einstein published his general theory of relativity. The theory has been tested many times experimentally, primarily in the relatively weak gravitational fields of the solar system [1,2]. More recently the first experimental results from the strong gravitational fields of two black holes have been measured in the form of gravitational waves, which are another prediction of general relativity. The 2017 Nobel prize in physics was awarded to Kip Thorne, Rainer Weiss, and Barry Barish for their role in the detection of gravitational waves. This year we have seen the first image of …

Mathematica Program To Compute Klein Gordon Equation For Generic Black Holes, Brant Smith

Physics Capstone Projects

The goal of this project is to develop a program that will compute the Klein Gordon equation for generic Black Holes through the program Mathematica. This program will be available on Utah State websites for public usage. This project focuses on an understanding of General Relativity and more concretely on theoretical aspects of Black Holes. Developing the program begins with computing the Laplace equation in flat space to understand what it means to have empty space without a Black Hole. The Klein Gordon equation for a Schwarzschild Black Hole is then solved to show what happens once a static, non-rotating …

Thermal Oxidation Of Silicon In A Home-Made Furnace System, Joshua Koskan

Physics Capstone Projects

I approached Dr. Shen with a desire for a project in understanding how to manage and expand the capabilities of a laboratory. After some discussion, my senior project was to complete a gas and water chiller system to an existing furnace for chemical vapor deposition. It should be able to handle temperatures up to 1100 ºC, hold a vacuum to mTorr, be easy to move samples in and out of the furnace, and cost effective.

3-Hydroxyflavones And 3-Hydroxy-4-Oxoquinolines As Carbon Monoxide-Releasing Molecules, Tatiana Soboleva, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Carbon monoxide-releasing molecules (CORMs) that enable the delivery of controlled amounts of CO are of strong current interest for applications in biological systems. In this review, we examine the various conditions under which CO is released from 3-hydroxyflavones and 3-hydroxy-4-oxoquinolines to advance the understanding of how these molecules, or derivatives thereof, may be developed as CORMs. Enzymatic pathways from quercetin dioxygenases and 3-hydroxy-4-oxoquinoline dioxygenases leading to CO release are examined, along with model systems for these enzymes. Base-catalyzed and non-redox-metal promoted CO release, as well as UV and visible light-driven CO release from 3-hydroxyflavones and 3-hydroxy-4-oxoquinolines, are summarized. The visible …

Optical Stability Of 1,1′-Binaphthyl Derivatives, Nikolay V. Tkachenko, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The racemization process of various 1,1′-binaphthyl derivatives is studied by quantum calculations. The preferred racemization pathway passes through a transition state belonging to the C_i symmetry group. The energy barrier for this process is independent of solvation, the electron-withdrawing/releasing power of substituents, or their ability to engage in H-bonds within the molecule. The primary factor is instead the substituent size. The barrier is thus reduced when the −OH groups of 1,1′-bi-2-naphthol are replaced by H. There is a drop in the barrier also when the substituents are moved from the 2,2′ positions to 6,6′, where they will not come …

Association Of Rare Coding Mutations With Alzheimer Disease And Other Dementias Among Adults Of European Ancestry, Devanshi Patel, Jesse Mez, Badri N. Vardarajan, Lyndsay Staley, Jaeyoon Chung, Xiaoling Zhang, John J. Farrell, Michael J. Rynkiewicz, Lisa A. Cannon-Albright, Craig C. Teerlink, Jeffery Stevens, Chris Corcoran, Et Al.

Mathematics and Statistics Faculty Publications

IMPORTANCE Some of the unexplained heritability of Alzheimer disease (AD) may be due to rare variants whose effects are not captured in genome-wide association studies because very large samples are needed to observe statistically significant associations.

OBJECTIVE To identify genetic variants associated with AD risk using a nonstatistical approach.

DESIGN, SETTING, AND PARTICIPANTS Genetic association study in which rare variants were identified by whole-exome sequencing in unrelated individuals of European ancestry from the Alzheimer’s Disease Sequencing Project (ADSP). Data were analyzed between March 2017 and September 2018.

MAIN OUTCOMES AND MEASURES Minor alleles genome-wide and in 95 genes previously associated …

Linear Operators That Preserve The Genus Of A Graph, Leroy B. Beasley, Jeong Han Kim, Seok-Zun Song

Mathematics and Statistics Faculty Publications

A graph has genus k if it can be embedded without edge crossings on a smooth orientable surface of genus k and not on one of genus k−1. A mapping of the set of graphs on n vertices to itself is called a linear operator if the image of a union of graphs is the union of their images and if it maps the edgeless graph to the edgeless graph. We investigate linear operators on the set of graphs on n vertices that map graphs of genus k to graphs of genus k and graphs of genus k+1 to graphs …

Ascending The Data Usability Gap In Mountainous Regions Through Scientist-Stakeholder Co-Production, Alan Rhoades

Spring Runoff Conference

No abstract provided.

Water Challenges In The Lower Colorado River Basin And The Drought Contingency Plan, Sharon Megdal

Spring Runoff Conference

No abstract provided.

Water Management In The West—A Federal Perspective, Brent Esplin

Spring Runoff Conference

No abstract provided.

Harmful Algae Blooms In Utah, Scott Daly

Spring Runoff Conference

No abstract provided.

An Update On Water Legislation From The 2019 Utah Legislative Session, Tim Hawkes

Spring Runoff Conference

No abstract provided.

Spring Runoff Conference 2019: Water Challenges In The West, Spring Runoff Conference

Spring Runoff Conference

The Spring Runoff Conference, hosted by the USU Water Initiative, is held annually on the campus of Utah State University. The conference provides a forum for interdisciplinary sharing and exchange of ideas on water-related issues in Utah and the lntermountain Region