Physical Sciences and Mathematics Commons^™

Environmental Factors Associated With Triploid Aspen Occurrence In Intermountain West Landscapes, Karen E. Mock, James A. Walton

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Polyploidy is common among plants and can contribute to physiological and morphological differences, altering how plants respond to environmental changes, promoting genetic diversification, and even species radiation. Quaking aspen (Populus tremuloides), a keystone species associated with high plant and animal diversity is frequently found in mixed diploid/triploid populations in the Intermountain West. High mortality rates and widespread population declines in aspen are of increasing concern in the Intermountain West, often ascribed to changing climates and drought stress events. The goal of this study was to better understand environmental factors influencing the distribution of triploid aspen population in the Intermountain West. …

Investigating Channel Narrowing And Nonnative Vegetation Encroachment In Three Dryland Rivers, Casey Pennock, Benjamin Miller, Phaedra Budy

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Water development and the proliferation of invasive riparian vegetation has led to widespread habitat loss and simplification of rivers in the western United States, contributing to the imperilment of native fishes. Here, we quantify channel narrowing and vegetation encroachment, which are conspicuous indicators of riverine habitat degradation, along approximately 400 km of three dryland tributaries of the upper Colorado River. To accomplish this, we conducted a comparative analysis of aerial photographs from historical (1930s) and contemporary (2010s or 2020s) time periods and utilized Light Detection and Ranging (LiDAR) data and Object-Based Image Analysis (OBIA) to determine contemporary canopy cover of …

Data For: Channel Response To Flow Augmentation: Diamond Fork River, Ut Dataset, Diane Wagner, Peter Wilcock

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A river's physical features and channel dimensions are determined by the water and sediment supplied to it. The Diamond Fork River, located in central Utah–received large trans-basin diversion flows from 1915-2003, providing an exceptional opportunity to explore the response of a river to a large increase in flow.

Our project goals were to describe 1) channel response to this large and long artificial flow augmentation and 2) how the channel recovered after the removal of the diversion flows. The objective of this thesis is to document the channel condition throughout the 20th century to present day as a basis for …

Data From: Climate Change-Driven Cumulative Mountain Pine Beetle-Caused Whitebark Pine Mortality In The Greater Yellowstone Ecosystem, William W. Macfarlane

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In 2018-2019 the Landscape Assessment System (LAS), an aerial survey method was used to assess mountain pine beetle (Dendroctonus ponderosae; MPB) - caused mortality of whitebark pine (Pinus albicaulis) across the Greater Yellowstone Ecosystem (59000 km2; GYE). This consisted of 11,942 km of flightlines, along which 4,434 geo-tagged, oblique aerial photos were captured and processed. A mortality rating of none to severe (0 to 4 nt attack or 5.0 5.4 old attack) was assigned to each photo based on the amount of red (recent attack) and gray (old attack) trees visible. The method produced a photo inventory of 74 percent …

Data From: Root Distributions Predict Shrub-Steppe Responses To Precipitation Intensity, Andrew Kulmatiski, Karen H. Beard

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Precipitation events are becoming more intense around the world, changing the way water moves through soils and plants. Plant rooting strategies that sustain water uptake under these conditions are likely to become more abundant (e.g., shrub encroachment). Yet, it remains difficult to predict species responses to climate change because we typically do not know where active roots are located or how much water they absorb. Here, we applied a water tracer experiment to describe forb, grass, and shrub root distributions. These measurements were made in 8 m by 8 m field shelters with low or high precipitation intensity. We used …

Nalidarturbopauseshear, Titus Yuan

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The USU Na lidar has been upgraded to be able to measure temperature and winds in the lower thermosphere up to ~ 115 km routinely. The new capability, coupled with the existing nightglow instruments at USU, enables the investigation of the extreme large wind and shears in this region and their correlation to the atmospheric gravity waves activities in the upper mesosphere.

Mesopause Region Temperature And Na Number Density Between 1990 And 2017, Tao Yuan, Chiao-Yao She

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The Colorado State University (CSU) Na lidar performed nocturnal mesopause region Na density and temperature observations between March 1990 and March 2010 at Fort Collins, CO (41.6N, 105W). The lidar was relocated to Utah State University (USU) campus and has continued its regular observation at Logan, Utah (42N, 112W) since September 2010.

Digital Atlas Of The Vascular Plants Of Utah, R. Douglas Ramsey, Leila M. Shultz, Wanda Lindquist, Chris Garrard, Mindy Wheeler

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Locations of 74,755 vascular plant vouchers representing 2,425 species were digitized into a spatial database from the Atlas of the Vascular Plants of Utah (Albee et al. 1988). Source maps consisted of 1:6,000,000-scale shaded relief maps of Utah with points representing collection locations by species. Location points, representing 1 or more specimens, were transposed onto these maps from the approximately 400,000 herbarium records of 3 major universities and federal land management agencies.

Supplementary Files For "Adaptive Mapping Of Design Ground Snow Loads In The Conterminous United States", Jadon Wagstaff, Jesse Wheeler, Brennan Bean, Marc Maguire, Yan Sun

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Recent amendments to design ground snow load requirements in ASCE 7-22 have reduced the size of case study regions by 91% from what they were in ASCE 7-16, primarily in western states. This reduction is made possible through the development of highly accurate regional generalized additive regression models (RGAMs), stitched together with a novel smoothing scheme implemented in the R software package remap, to produce the continental- scale maps of reliability-targeted design ground snow loads available in ASCE 7-22. This approach allows for better characterizations of the changing relationship between temperature, elevation, and ground snow loads across the Conterminous United …

Pariette Wetlands Water, Sediment And Plant Total Selenium Concentration, Colleen P. Jones, Paul R. Grossl, Astrid R. Jacobson

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We measured total Selenium in plants from July through November of 2012 and in water, macroinvertebrates, plants, and sediments from July of 2014 from Pariette Wetlands, Utah, U.S.A. to test for spatial, temporal, plant species and plant tissue distribution of Selenium.

Air Pollutant Emissions From Natural Gas-Fueled Pumpjack Engines In The Uinta Basin, Seth Lyman

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We measured a comprehensive suite of pollutants emitted from 58 natural gas-fueled pumpjack engines in Utah’s Uinta Basin between January and May 2021, with repeat measurements of five engines in January 2022. We documented the emissions composition of several makes and models of commonly used engines, including Ajax E42, E565, DP60, and DP80 engines; Arrow L795, C101, and C106 engines; and GM Vortec.

Elemental And Oxidized Mercury In The Atmosphere At Horsepool, Utah, January-July 2019, Seth Lyman

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This is a dataset of elemental and oxidized mercury in the ambient atmosphere at latitude 40.143° N and longitude 109.469° W. This is the location of the Horsepool monitoring station in the Uinta Basin, Utah. We collected these measurements using a dual-channel atmospheric mercury speciation instrument, which is described by Lyman, S. N., Gratz, L. E., Dunham-Cheatham, S. M., Gustin, M. S., & Luippold, A. (2020). Improvements to the accuracy of atmospheric oxidized mercury measurements. Environmental Science & Technology, 54(21), 13379-13388.

Supplementary Files For "Creating A Universal Depth-To-Load Conversion Technique For The Conterminous United States Using Random Forests", Jesse Wheeler, Brennan Bean, Marc Maguire

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As part of an ongoing effort to update the ground snow load maps in the United States, this paper presents an investigation into snow densities for the purpose of predicting ground snow loads for structural engineering design with ASCE 7. Despite their importance, direct measurements of snow load are sparse when compared to measurements of snow depth. As a result, it is often necessary to estimate snow load using snow depth and other readily accessible climate variables. Existing depth-to-load conversion methods, each of varying complexity, are well suited for snow load estimation for a particular region or station network, but …

Data From: Yellow Air Day Advisory Study, Arthur J. Caplan

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Using a dataset consisting of daily vehicle trips, PM2.5 concentrations, along with a host of climactic control variables, we test the hypothesis that “yellow air day” advisories provided by the Utah Division of Air Quality resulted in subsequent reductions in vehicle trips taken during northern Utah’s winter-inversion seasons in the early 2000s. Winter inversions occur in northern Utah when climactic conditions are such that PM2.5 concentrations (derived mainly from vehicle emissions) become trapped in the lower atmosphere, leading to unhealthy air quality (concentrations of at least 35 µg/m3) over a span of what are called “red air days”. When concentrations …

Data From: High-Resolution Photoelectron Imaging Of Irb3-: Observation Of A P-Aromatic B3+ Ring Coordinated To A Transition Metal, Alexander I. Boldyrev, Maksim Kulichenko

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In a high-resolution photoelectron imaging and theoretical study of the IrB3− cluster, two isomers were observed experimentally with electron affinities (EAs) of 1.3147(8) and 1.937(4) eV. Quantum calculations revealed two nearly degenerate isomers competing for the global minimum, both with a B3 ring coordinated with the Ir atom.

Data From: Spherical Aromaticity In Inorganic Chemistry, Alexander I. Boldyrev, Maksim Kulichenko

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Chapter "14 - Spherical aromaticity in inorganic chemistry" in a book "Aromaticity - Modern Computational Methods and Applications"

Data From: Hydrated Sulfate Clusters So4(2-)(H2o)N(N=1-40): Charge Distribution Through Solvation Shells And Stabilization, Alexander I. Boldyrev, Maksim Kulichenko

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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 place at a number of H2O molecules n ≤ 7. The SO4(2–) directly donates its charge only to the first solvation shell and surprisingly, a small amount of electron density of 0.15|e| is enough to be transferred in order to stabilize the dianion.

Data From: Expansion Of Aromaticity Magnetic Criteria On Multi-Layer Structures. Magnetic Response And Spherical Aromaticity Of Matryoshka-Like [Sn@Cu12@Sn20]12- Cluster, Alexander I. Boldyrev, Maksim Kulichenko

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Structural characterization of the discrete [Sn@Cu12@Sn20]12− cluster exposed a fascinating architecture composed of three concentric structural layers in which an endohedral Sn atom is enclosed in a Cu12 icosahedron, which in turn is embedded in an Sn20 dodecahedron. Herein, the possibility of sustaining aromatic behavior for this prototypical multilayered species was evaluated, in order to extend this concept to more complex clusters on the basis of magnetic response and bonding analysis by the AdNDP approach. This revealed characteristic features of spherical aromatics, given by the ability to sustain the shielding cone property, similar to archetypal aromatics.

Data From: Σ-Aromaticity In The Mos2 Monolayer, Alexander I. Boldyrev, Maksim Kulichenko

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As is shown using the SSAdNDP approach, Mo and S form 2-centered bonds and there is a lone pair on each S. Most importantly, the remaining electrons are distributed over Mo atoms and form conjugated aromatic σ-bonds inside every hexagonal ring, which makes molybdenum the main carrier of σ-aromaticity.

Data From: Periodic F-Defects On The Mgo Surface As Potential Single-Defect Catalysts With Non-Linear Optical Properties, Alexander I. Boldyrev, Maksim Kulichenko

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In this paper we suggest a new type of a single-atom (or single-defect) catalyst – MgO with periodic defects on the (0 0 1) surface – which possesses noticeable non-linear optical properties. Periodicity of these defects leads to the significant extensive increase in the activity of a catalyst by growth of the concentration of active sites. In this work we showed the presence of diffuse electride-like multi-center bonds inside every periodic F-center. We also discovered that MgO with periodic defects on the surface gains non-linear optical properties due to electride-like polarizable bonds inside every defect. And most importantly, such defective …

Data From: 'Bottled' Spiro-Doubly Aromatic Trinuclear [Pd2ru]+ Complexes, Alexander I. Boldyrev, Maksim Kulichenko

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The central unit of the synthesized structure is a Ru atom which is the vertex of the [RuPd2]+ triangle being the first example of mixed triangles among these metals. Moreover, Ru is involved in both σ- and π-aromaticity. σ-aromaticity is realized as the d-AO based multicenter bond which is delocalized over the inner [RuPd2]+ triangle with considerable contribution from the sulfur electron density. Besides, transition metals are known to interact with the electron cloud of benzene which, in turn, leads to the charge transfer and formation of conjugated electron density between the TM and benzene. The second type of aromaticity, …

Data From: Can Aromaticity Be A Kinetic Trap? Example Of Mechanically Interlocked Aromatic [2-5]Catenanes Built From Cyclo[18]Carbon, Alexander I. Boldyrev, Nikita Fedik

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Project reports the analysis of interlocked C18 rings as building blocks for polycatenanes.

Data From: Boron-Made N2: Realization Of A Bb Triple Bond In The B2al3- Cluster, Alexander I. Boldyrev, Nikita Fedik

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Project reports B2Al3- cluster, which mimics triple bond N2 molecule.

Data From: Two Names Of Stability: Spherical Aromatic Or Superatomic Intermetalloid Cluster [Pd3sn8bi6]4−, Alexander I. Boldyrev, Nikita Fedik

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Project reports the aromaticity in the intermetalloid cluster [Pd3Sn8Bi6]4−.

Data From: Chemical Bonding Analysis Of Excited States Using The Adaptive Natural Density Partitioning Method, Alexander I. Boldyrev, Nikolay Tkachenko

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A novel approach to chemical bond analysis for excited states has been developed. Using an extended adaptive natural density partitioning method (AdNDP) as implemented in AdNDP 2.0 code, we obtained chemically intuitive bonding patterns for the excited states of H2O, B5+, and C2H4+ molecules. The deformation pathway in the excited states could be easily predicted based on the analysis of the chemical bond pattern. We expect that this new method of chemical bonding analysis would be very helpful for photochemistry, photoelectron spectroscopy, electron spectroscopy and other chemical applications that involved excited states.

Data From: Stability, Electronic, And Optical Properties Of Two-Dimensional Phosphoborane, Alexander I. Boldyrev, Nikolay Tkachenko

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The structure and properties of two-dimensional phosphoborane sheets were computationally investigated using Density Functional Theory calculations. The calculated phonon spectrum and band structure point to dynamic stability and allowed characterization of the predicted two-dimensional material as a direct-gap semiconductor with a band gap of ~1.5 eV. The calculation of the optical properties showed that the two-dimensional material has a relatively small absorptivity coefficient. The parameters of the mechanical properties characterize the two-dimensional phosphoborane as a relatively soft material, similar to the monolayer of MoS2. Assessment of thermal stability by the method of molecular dynamics indicates sufficient stability of the predicted …

Data From: Novel Strongly Correlated Europium Superhydrides, Alexander I. Boldyrev, Nikolay Tkachenko

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We conducted a joint experimental–theoretical investigation of the high-pressure chemistry of europium polyhydrides at pressures of 86–130 GPa. We discovered several novel magnetic Eu superhydrides stabilized by anharmonic effects: cubic EuH9, hexagonal EuH9, and an unexpected cubic (Pm3n) clathrate phase, Eu8H46. Monte Carlo simulations indicate that cubic EuH9 has antiferromagnetic ordering with TN of up to 24 K, whereas hexagonal EuH9 and Pm3n-Eu8H46 possess ferromagnetic ordering with TC = 137 and 336 K, respectively. The electron–phonon interaction is weak in all studied europium hydrides, and their magnetic ordering excludes s-wave superconductivity, except, perhaps, for distorted pseudohexagonal EuH9. The equations of …

Data From: A Sandwich-Type Cluster Containing Ge@Pd3 Planar Fragment Flanked By Aromatic Nonagermanide Caps, Alexander I. Boldyrev, Nikolay Tkachenko

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Sandwich-type clusters with the planar fragment containing a heterometallic sheet have remained elusive. In this work, we introduce the [K(2,2,2-crypt)]4{(Ge9)2[η6-Ge(PdPPh3)3]} complex that contains a heterometallic sandwich fragment. The title compound is structurally characterized by means of single-crystal X-ray diffraction, which reveals the presence of an unusual heteroatomic metal planar fragment Ge@Pd3. The planar fragment contains a rare formal zerovalent germanium core and a peculiar bonding mode of sp2-Ge@(PdPPh3)3 trigonal planar structure, whereas the nonagermanide fragments act as capping ligands. The chemical bonding pattern of the planar fragment consists of three 2c-2e Pd-Ge σ-bonds attaching Pd atoms to the core Ge …

Dataset For: Multiple Local Σ-Aromaticity Of Nonagermanide Clusters, Alexander I. Boldyrev, Nikolay Tkachenko

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Nonagermanide clusters are widely used in inorganic synthesis and are actively studied by experimentalists and theoreticians. However, chemical bonding of such versatile species is still not completely understood. In our work we deciphered a bonding pattern for various experimentally obtained nonagermanide species. We localized the electron density via the AdNDP algorithm for the model structures ([Ge9]4−, [Ge9{P(NH2)2}3]−, Cu[Ge9{P(NH2)2}3] and Cu(NHC)[Ge9{P(NH2)2}3]) and obtained a simple and chemically intuitive bonding pattern which can explain the variety of active sites and the existence of both D3h and C4v geometries for such clusters. Moreover, the [Ge9]4− core is found to be a unique example …

Data For: Record Low Ionization Potentials Of Alkali Metal Complexes With Crown Ethers And Cryptands, Alexander I. Boldyrev, Nikolay Tkachenko

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Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70–1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.