Physical Sciences and Mathematics Commons^™

Vortex Sheet Sensitivity To Low-Level Vertical Shear And Airmass Temperature Perturbation, Adam L. Houston, George L. Limpert

Department of Earth and Atmospheric Sciences: Faculty Publications

A theoretical, numerical-modeling-based examination of the sensitivity of vortex sheets along airmass boundaries to the following three characteristics is presented: 1) boundary-normal component of the vertical wind shear, 2) boundary-parallel component of the vertical wind shear, and 3) temperature perturbation within the parent air mass of the boundary. The overall aim of this work is to advance understanding of the sensitivity of micro-α- tomeso-γ-scale vortex generation along airmass boundaries to the ambient environment. Density currents are simulated in a 2D domain that does not allow baroclinic generation of near-surface vertical vorticity (ζ_ns) with parameterized latent heating for convection …

First Search For Exclusive Diphoton Production At High Mass With Tagged Protons In Proton-Proton Collisions At √S =13 Tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp → pγγp with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb⁻¹ collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeVat the LHC. Events are selected with a diphoton invariant mass above 350 GeVand with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity …

Time-Varying Resonant Mass At Collider And Beam Dump Experiments, Jinhui Guo, Yuxuan He, Jia Liu, Xiao-Ping Wang, Ke-Pan Xie

Department of Physics and Astronomy: Faculty Publications

A new particle usually manifests itself as a single resonant peak located at its mass. We propose if the new particle mass is time-varying due to environmental effects, then its mass spectrum typically has a novel double-peak feature. A representative model is the kinetic mixing dark photon interacting with an ultralight complex scalar dark matter charged under U(1)'. We reanalyze the existing experiments, showing the constraints on such a model are drastically weakened than those on the traditional single-peak resonance model, due to the reduction of the luminosity exposure in each resonant mass bin. Consequently, for mass around tens …

The Ddt-Induced Decline Influenced Genetic Diversity In Naturally Recovered Peregrine Falcons (Falco Peregrinus) Nesting Within The Alaska Arctic And Eastern Interior, Sarah A. Sonsthagen,, Ted Swem, Skip Ambrose, Melanie J. Flamme, Clayton M. White, George K. Sage, Sandra L. Talbot

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

We assessed the influence of the severe mid-20th century population decline on genetic diversity in nonaugmented Peregrine Falcon Falco peregrinus populations nesting within the Alaska Arctic and eastern Interior. Microsatellite and mitochondrial DNA (mtDNA) data were analysed for Peregrine Falcons sampled from three periods: pre-decline, decline and post-decline. The influence of the decline on genetic diversity differed between the two locales. The Alaska Arctic was characterized by shifts in mtDNA haplotype frequencies, increased inbreeding coefficient, reduction in effective population size and increase in private haplotypes, and a signature of post-decline population growth was detected; by contrast, the eastern Interior showed …

Induced Spin Textures At 3D Transition Metal–Topological Insulator Interfaces, Slimane Laref, Sumit Ghosh, Evgeny Y. Tsymbal, Aurelien Manchon

Department of Physics and Astronomy: Faculty Publications

While some of the most elegant applications of topological insulators, such as the quantum anomalous Hall effect, require the preservation of Dirac surface states in the presence of time-reversal symmetry breaking, other phenomena such as spin-charge conversion rather rely on the ability for these surface states to imprint their spin texture on adjacent magnetic layers. In this Rapid Communication, we investigate the spin-momentum locking of the surface states of a wide range of monolayer transition metals (3d-TM) deposited on top of Bi₂Se₃ topological insulators using first-principles calculations. We find an anticorrelation between the magnetic moment …

Mentoring Undergraduate Research In Mathematical Modeling, Glenn Ledder

Department of Mathematics: Faculty Publications

In writing about undergraduate research in mathematical modeling, I draw on my 31 years as a mathematics professor at the University of Nebraska–Lincoln, where I mentored students in honors’ theses, REU groups, and research done in a classroom setting, as well as my prior experience. I share my views on the differences between research at the undergraduate and professional levels, offer advice for undergraduate mentoring, provide suggestions for a variety of ways that students can disseminate their research, offer some thoughts on mathematical modeling and how to explain it to undergraduates, and discuss the challenges involved in broadening research participation …

Mentoring Undergraduate Research In Mathematical Modeling, Glenn Ledder

Department of Mathematics: Faculty Publications

In writing about undergraduate research in mathematical modeling, I draw on my 31 years as a mathematics professor at the University of Nebraska–Lincoln, where I mentored students in honors’ theses, REU groups, and research done in a classroom setting, as well as my prior experience. I share my views on the differences between research at the undergraduate and professional levels, offer advice for undergraduate mentoring, provide suggestions for a variety of ways that students can disseminate their research, offer some thoughts on mathematical modeling and how to explain it to undergraduates, and discuss the challenges involved in broadening research participation …

Superfluid Spin Transistor, Edward Schwartz, Bo Li, Alexey Kovalev

Department of Physics and Astronomy: Faculty Publications

We propose to use the Hall response of topological defects, such as merons and antimerons, to spin currents in two-dimensional magnetic insulator with in-plane anisotropy for identification of the Berezinskii-Kosterlitz-Thouless (BKT) transition in a transistorlike geometry. Our numerical results relying on a combination of Monte Carlo and spin dynamics simulations show transition from spin superfluidity to conventional spin transport, accompanied by the universal jump of the spin stiffness and exponential growth of the transverse vorticity current. We propose a superfluid spin transistor in which the spin and vorticity currents are modulated by changes in density of free topological defects, e.g., …

Population Genetics Reveals Bidirectional Fish Movement Across The Continental Divide Via An Interbasin Water Transfer, Audrey C. Harris, Sara J. Oyler-Mccance, Jennifer A. Fike, Matthew P. Fairchild, Christopher M. Kennedy, Harry J. Crockett, Dana L. Winkelman, Yoichiro Kanno

United States Geological Survey: Staff Publications

Interbasin water transfers are becoming an increasingly common tool to satisfy municipal and agricultural water demand, but their impacts on movement and gene flow of aquatic organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. We used single nucleotide polymorphisms to characterize population genetic structure in cutthroat trout (Oncorhynchus clarkii) and determine if fish utilize the Grand Ditch as a movement corridor. …

Gull Plumages Are, And Are Not, What They Appear To Human Vision, Muir D. Eaton, Pilar Benites, Luke Campillo, Robert E. Wilson, Sarah A. Sonsthagen

School of Natural Resources: Faculty Publications

Clear correlations between human and bird visual assessments of color have been documented, and are often assumed, despite fundamental differences in human and avian visual physiology and morphology. Analyses of plumage colors with avian perceptual models have shown widespread hidden inter-sexual and inter-specific color variation among passerines perceived as monochromatic to humans, highlighting the uncertainty of human vision to predict potentially relevant variation in color. Herein, we use reflectance data from 13 Larus gull species as an exemplar data set to study concordance between human vision and avian visual modeling of feather colors near, or below, the human threshold for …

Foraging Habitat Selection Of Shrubland Bird Community In Tropical Dry Forest, Anant Deshwal, Steven L. Stephenson, Pooja Panwar, Brett A. Degregorio, Ragupathy Kannan, John D. Willson

United States Geological Survey: Staff Publications

Habitat loss due to increasing anthropogenic disturbance is the major driver for bird population declines across the globe. Within the Eastern Ghats of India, shrubland bird communities are threatened by shrinking of suitable habitats due to increased anthropogenic disturbance and climate change. The development of an effective habitat management strategy is hampered by the absence of data for this bird community. To address this knowledge gap, we examined foraging sites for 14 shrubland bird species, including three declining species, in three study areas representing the shrubland type of forest community in the Eastern Ghats. We recorded microhabitat features within an …

The Natural History And Ecology Of Melanism In Red Wolf And Coyote Populations Of The Southeastern United States – Evidence For Gloger’S Rule, Joseph W. Hinton, Kyla M. West, Daniel J. Sullivan, Jacqueline L. Frair, Michael J. Chamberlain

United States Environmental Protection Agency: Publications

Background: Gloger’s rule postulates that animals should be darker colored in warm and humid regions where dense vegetation and dark environments are common. Although rare in Canis populations, melanism in wolves is more common in North America than other regions globally and is believed to follow Gloger’s rule. In the temperate forests of the southeastern United States, historical records of red wolf (Canis rufus) and coyote (Canis latrans) populations document a consistent presence of melanism. Today, the melanistic phenotype is extinct in red wolves while occurring in coyotes and red wolf-coyote hybrids who occupy the …

First-Order Phase Transition And Fate Of False Vacuum Remnants, Kiyoharu Kawana, Philip Lu, Ke-Pan Xie

Department of Physics and Astronomy: Faculty Publications

False vacuum remnants in first-order phase transitions in the early Universe can form compact objects which may constitute dark matter. Such remnants form because particles develop large mass gaps between the two phases and become trapped in the old phase. We focus on remnants generated in a class of models with trapped dark sector particles, trace their development, and determine their ultimate fate. Depending on model and phase transition parameters, the evolutionary endpoint of these remnants can be primordial black holes, Fermi-balls, Q-balls, or thermal balls, and they all have the potential to constitute some portion or the whole of …

The Status Of Posidonia Oceanica At Tremiti Islands Marine Protected Area (Adriatic Sea), Andrea Tursi, Francesco Mastrototaro, Federica Montesanto, Francesco De Giosa, Anna Lisco, Antonella Bottalico, Giovanni Chimienti

School of Natural Resources: Faculty Publications

Simple Summary: The seagrass Posidonia oceanica is the most important marine phanerogam of the Mediterranean Sea due to its meadows’ complexity, persistence, and extension. These habitats provide a suite of ecosystem goods and services, being of primary importance in marine conservation. Despite their central role in the coastal ecology, P. oceanica meadows are undergoing overall deterioration and fragmentation in the basin mostly due to anthropogenic impacts at local to global scales. In the last decades, several management measures have been proposed aiming to improve the meadow health conditions, while the periodic monitoring of P. oceanica meadows allows for verifying their …

On Approximating Total Variation Distance, Arnab Bhattacharyya, Sutanu Gayen, Kuldeep S. Meel, Dimitrios Myrisiotis, A. Pavan, N. V. Vinodchandran

School of Computing: Faculty Publications

Total variation distance (TV distance) is a fundamental notion of distance between probability distributions. In this work, we introduce and study the computational problem of determining the TV distance between two product distributions over the domain {0, 1}ⁿ. We establish the following results.

1. Exact computation of TV distance between two product distributions is #P-complete. This is in stark contrast with other distance measures such as KL, Chi-square, and Hellinger which tensorize over the marginals.

2. Given two product distributions P and Q with marginals of P being at least 1/2 and marginals of Q being at most …

Differential Operators On Classical Invariant Rings Do Not Lift Modulo P, Jack Jeffries, Anurag K. Singh

Department of Mathematics: Faculty Publications

Levasseur and Stafford described the rings of differential operators on various classical invariant rings of characteristic zero; in each of the cases that they considered, the differential operators form a simple ring. Towards an attack on the simplicity of rings of differential operators on invariant rings of linearly reductive groups over the complex numbers, Smith and Van den Bergh asked if differential operators on the corresponding rings of positive prime characteristic lift to characteristic zero differential operators. We prove that, in general, this is not the case for determinantal hypersurfaces, as well as for Pfaffian and symmetric determinantal hypersurfaces. We …

A Room-Temperature Ferroelectric Resonant Tunneling Diode, Zhijun Ma,, Qi Zhang, Lingling Tao, Yihao Wang, Daniel Sando, Jinling Zhou, Yizhong Guo, Michael Lord, Peng Zhou, Yongqi Ruan, Zhiwei Wang, Alex Hamilton, Alexei Gruverman, Evgeny Y. Tsymbal, Tianjin Zhang, Nagarajan Valanoor

Department of Physics and Astronomy: Faculty Publications

Resonant tunneling is a quantum-mechanical effect in which electron transport is controlled by the discrete energy levels within a quantum-well (QW) structure. A ferroelectric resonant tunneling diode (RTD) exploits the switchable electric polarization state of the QW barrier to tune the device resistance. Here, the discovery of robust room-temperature ferroelectric-modulated resonant tunneling and negative differential resistance (NDR) behaviors in all-perovskite-oxide BaTiO₃/SrRuO₃/BaTiO₃ QW structures is reported. The resonant current amplitude and voltage are tunable by the switchable polarization of the BaTiO₃ ferroelectric with the NDR ratio modulated by ≈3 orders of magnitude and an OFF/ON …

Four-Field Hamiltonian Fluid Closures Of The One-Dimensional Vlasov-Poisson Equation, C. Chandre, Bradley Allan Shadwick

Department of Physics and Astronomy: Faculty Publications

We consider a reduced dynamics for the first four fluid moments of the one-dimensional Vlasov-Poisson equation, namely, the fluid density, fluid velocity, pressure and heat flux. This dynamics depends on an equation of state to close the system. This equation of state (closure) connects the fifth order moment—related to the kurtosis in velocity of the Vlasov distribution—with the first four moments. By solving the Jacobi identity, we derive an equation of state which ensures that the resulting reduced fluid model is Hamiltonian. We show that this Hamiltonian closure allows symmetric homogeneous equilibria of the reduced fluid model to be stable.

Genomic Tools Reveal Complex Social Organization Of An Invasive Large Mammal (Sus Scrofa), Chelsea L. Titus, Courtney F. Bowden, Timothy J. Smyser, Stephen L. Webb, James C. Beasley

United States Department of Agriculture Wildlife Services: Staff Publications

A comprehensive understanding of sociality in wildlife is vital to optimizing conservation and management efforts. However, sociality is complicated, especially for widely distributed species that exhibit substantive behavioral plasticity. Invasive wild pigs (Sus scrofa), often representing hybrids of European wild boar and domestic pigs, are among the most adaptable and widely distributed large mammals. The social structure of wild pigs is believed to be similar to European wild boar, consisting of matriarchal groups (sounders) and solitary males. However, wild pig social structure is understudied and largely limited to visual observations. Using a hierarchical approach, we incorporated genomic tools …

The Dynamic Floor Of Yellowstone Lake, Wyoming, Usa: The Last 14 K.Y. Of Hydrothermal Explosions, Venting, Doming, And Faulting, L. A. Morgan, W. C.P. Shanks, K. L. Pierce, N. Iverson, C. M. Schiller, S. R. Brown, P. Zahajska, R. Cartier, R. W. Cash, J. L. Best, C. Whitlock, Sherilyn C. Fritz, U.S. Geological Survey, H. Lowers, D. A. Lovalvo, J. M. Licciardi

Department of Earth and Atmospheric Sciences: Faculty Publications

Hydrothermal explosions are significant potential hazards in Yellowstone National Park, Wyoming, USA. The northern Yellowstone Lake area hosts the three largest hydrothermal explosion craters known on Earth empowered by the highest heat flow values in Yellowstone and active seismicity and deformation. Geological and geochemical studies of eighteen sublacustrine cores provide the first detailed synthesis of the age, sedimentary facies, and origin of multiple hydrothermal explosion deposits.New tephrochronology and radiocarbon results provide a four-dimensional view of recent geologic activity since recession at ca. 15–14.5 ka of the >1-km-thick Pinedale ice sheet.

The sedimentary record in Yellowstone Lake contains multiple hydrothermal explosion …

Using Nuradiomc To Study The Performance Of Uhe Radio Neutrino Detectors, S. Bouma, B. Clark, P. Giri, C. Glaser, S. Hallmann, N. Heyer, Ilya Kravchenko, A. Nelles, B. Oeyen, I. Plaisier, L. Pyras, F. Schlüter, C. Welling

Department of Physics and Astronomy: Faculty Publications

NuRadioMC is an open-source, Python-based simulation and reconstruction framework for radio detectors of ultra-high energy neutrinos and cosmic rays. Its modular design makes NuRadioMC suitable for use with a range of past, current and future detectors. In addition, the recent deployment of a complete documentation as well as a pip release make NuRadioMC relatively easy to learn and use. Here, we outline the features currently available and under development in NuRadioMC, with a focus on its usage to simulate and study in-ice radio neutrino detectors.

The Radio Neutrino Observatory Greenland (Rno-G): Status Update, Steffen Hallmann

Department of Physics and Astronomy: Faculty Publications

The Radio Neutrino Observatory in Greenland (RNO-G) is an in-ice radio detector for ultrahigh energy neutrinos with the potential to make the first detection of a neutrino shower beyond ∼10 PeV via the Askaryan emission. With a projected 90% CL upper limit below 𝐸²Φ ≈ 10⁻⁸ GeV/cm²/s/sr within 10 years of operation, RNO-G will reach realistic models of GZK and astrophysical neutrino fluxes. In 2021, the first three stations of RNO-G were installed and started data-taking. Four additional stations were added in 2022 with some upgrades to the station hardware. Here, we present the current …

Searching For Air Showers With Rno-G, Jakob Henrichs

Department of Physics and Astronomy: Faculty Publications

The Radio Neutrino Observatory – Greenland (RNO-G) is an in-ice neutrino detector, using radio emission to target the first measurement of neutrinos beyond PeV energies. In total 35 stations are planned for the detector, resulting in a detection volume of around 100 km³. Each of these stations is equipped with deep antennas embedded ∼ 100 m into the ice and downward-pointing log-periodic dipole antennas (LPDA) buried ∼ 3 m into the snow. At each station, three additional buried LPDA are pointing towards the sky and thus can be used to look for cosmic-ray induced air-showers. These air showers are a …

Angular Resolution For The Radio Neutrino Observatory Greenland (Rno-G), Ilse Plaisier

Department of Physics and Astronomy: Faculty Publications

In the ultra-high energy regime, the low predicted neutrino fluxes are out of reach for currently running neutrino detectors. Larger instrumented volumes are needed to probe these lowfluxes. The Radio Neutrino Observatory Greenland (RNO-G) detects in-ice radio waves emitted by neutrino induced particle showers in the Greenlandic ice sheet. Radio waves have a large attenuation length in ice O(1 km) and therefore RNO-G implements a sparse instrumentation to cover an unprecedented volume. The first seven RNO-G stations have been deployed in the summer of 2021 and 2022 and deployment will be ongoing in the next years. This contribution discusses …

Tunable Physical Properties In Bi-Based Layered Supercell Multiferroics Embedded With Au Nanoparticles, Jianan Shen, Zihao He, Di Zhang, Ping Lu, Julia Deitz, Zhongxia Shang, Matias Kalaswad, Haohan Wang, Xiaoshan S. Xu, Haiyan Wang

Department of Physics and Astronomy: Faculty Publications

Multiferroic materials are an interesting functional material family combining two ferroic orderings, e.g., ferroelectric and ferromagnetic orderings, or ferroelectric and antiferromagnetic orderings, and find various device applications, such as spintronics, multiferroic tunnel junctions, etc. Coupling multiferroic materials with plasmonic nanostructures offers great potential for optical-based switching in these devices. Here, we report a novel nanocomposite system consisting of layered Bi_1.25AlMnO_3.25 (BAMO) as a multiferroic matrix and well dispersed plasmonic Au nanoparticles (NPs) and demonstrate that the Au nanoparticle morphology and the nanocomposite properties can be effectively tuned. Specifically, the Au particle size can be tuned from …

Noncanonical Amino Acid Mutagenesis In Response To Recoding Signal-Enhanced Quadruplet Codons, Yan Chen, Xinyuan He, University Of Nebraska-Lincoln, Kun Liu, Tian Gao, Wei Niu, Jiantao Guo

Chemistry Department: Faculty Publications

While amber suppression is the most common approach to introduce noncanonical amino acids into proteins in live cells, quadruplet codon decoding has potential to enable a greatly expanded genetic code with up to 256 new codons for protein biosynthesis. Since triplet codons are the predominant form of genetic code in nature, quadruplet codon decoding often displays limited efficiency. In this work, we exploited a new approach to significantly improve quadruplet UAGN and AGGN (N = A, U, G, C) codon decoding efficiency by using recoding signals imbedded in mRNA. With representative recoding signals, the expression level of mutant proteins containing …

Tracing Geochemical Sources And Health Risk Assessment Of Uranium In Groundwater Of Arid Zone Of India, P. Pandit, Atul Saini, Sabarathinam Chidambaram, Vinod Kumar, Banjarani Panda, A. L. Ramanathan, Netrananda Sahu, A. K. Singh, Rohit Mehra

Nebraska Water Center: Faculty Publications

Water quality degradation and metal contamination in groundwater are serious concerns in an arid region with scanty water resources. This study aimed at evaluating the source of uranium (U) and potential health risk assessment in groundwater of the arid region of western Rajasthan and northern Gujarat. The probable source of vanadium (V) and fluorine (F) was also identified. U and trace metal concentration, along with physicochemical characteristics were determined for 265 groundwater samples collected from groundwater of duricrusts and palaeochannels of western Rajasthan and northern Gujarat. The U concentration ranged between 0.6 and 260 μg L⁻¹ with a mean …

Valuing Angling On Reservoirs Using Benefit Transfer, Richard T. Melstrom, Mark A. Kaemingk, Nicholas W. Cole, John C. Whitehead, Christopher J. Chizinski, Kevin L. Pope

Nebraska Cooperative Fish and Wildlife Research Unit: Staff Publications

Economic assessments are rarely applied to inland recreational fisheries for management purposes, especially when compared to fish, habitat, and creel assessments, yet economic assessments can provide critical information for management decisions. We provide a brief overview of economic value, key terminology, and existing economic techniques to address these issues. Benefit transfer, a technique used to measure economic value when an original analysis is not practicable, is conducted by drawing on existing estimates of economic value in similar contexts. We describe an application of benefit transfer to measure the economic value of several recreational fisheries in Nebraska, USA. We examine two …

Single-Pass Inline Pipeline 3d Reconstruction Using Depth Camera Array, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

A novel inline inspection (ILI) approach using depth cameras array (DCA) is introduced to create high-fidelity, dense 3D pipeline models. A new camera calibration method is introduced to register the color and the depth information of the cameras into a unified pipe model. By incorporating the calibration outcomes into a robust camera motion estimation approach, dense and complete 3D pipe surface reconstruction is achieved by using only the inline image data collected by a self-powered ILI rover in a single pass through a straight pipeline. The outcomes of the laboratory experiments demonstrate one-millimeter geometrical accuracy and 0.1-pixel photometric accuracy. …

Speciation With Gene Flow In A Narrow Endemic West Virginia Cave Salamander (Gyrinophilus Subterraneus), Evan H. Campbell Grant, Kevin P. Mulder, Adrianne B. Brand, Douglas B. Chambers, Addison H. Wynn, Grace Capshaw, Matthew L. Niemiller, John G. Phillips, Jeremy F. Jacobs, Shawn R. Kuchta, Rayna C. Bell

United States Geological Survey: Staff Publications

Due to their limited geographic distributions and specialized ecologies, cave species are often highly endemic and can be especially vulnerable to habitat degradation within and surrounding the cave systems they inhabit. We investigated the evolutionary history of the West Virginia Spring Salamander (Gyrinophilus subterraneus), estimated the population trend from historic and current survey data, and assessed the current potential for water quality threats to the cave habitat. Our genomic data (mtDNA sequence and ddRADseq-derived SNPs) reveal two, distinct evolutionary lineages within General Davis Cave corresponding to G. subterraneus and its widely distributed sister species, Gyrinophilus porphyriticus, that …