Physical Sciences and Mathematics Commons^™

Electron Interference In Atomic Ionization By Two Crossing Polarized Ultrashort Pulses, Jean Marcel Ngoko Djiokap, A. V. Meremianin, N. L. Manakov

Department of Physics and Astronomy: Faculty Publications

Formation of geometrically regular interference patterns in the photoelectron momentum distributions (PMDs) corresponding to the photoionization of atoms by two single-color, crossing ultrashort pulses is investigated both analytically and numerically. It is shown that, in contrast to the photoionization by monochromatic pulses, PMDs for the ionization by crossing and co-propagating broadband pulses are essentially different (unless both pulses are linearly polarized), namely, when one pulse is linearly polarized along the propagation direction, [], of the circularly polarized (CP) pulse, then interference maxima (minima) of the ionization probability have the form of three-dimensional single-arm regular spirals which are wound along []. …

Decline Of Novel Ecosystems Used By Endangered Species: The Case Of Piping Plovers, Least Terns, And Aggregate Mines, Joel G. Jorgensen, Stephen J. Brenner, Lauren R. Greenwalt, Mark P. Vrtiska

School of Natural Resources: Faculty Publications

Sand and gravel mining creates novel ecosystems along the Platte, Loup, and Elkhorn rivers in Nebraska, USA. Piping plovers and least terns are state and/or federally threatened and endangered species, respectively, that nest and raise young at these sites and their derivatives. Despite hosting relatively large numbers of piping plovers and least terns for decades, an important question that has largely gone unaddressed is whether the industry that has produced these novel ecosystems is stable and will continue to produce habitat consistently in the future. We evaluated how the number, size, and spatial distribution of different site types hosting different …

Flash Drought Onset Over The Contiguous United States: Sensitivity Of Inventories And Trends To Quantitative Definitions, Mahmoud Osman, Bejamin F. Zaitchik, Hamada S. Badr, Jordan I. Christian, Tsegaye Tadesse, Jason A. Otkin, Martha C. Anderson

Drought Mitigation Center: Faculty Publications

The term “flash drought” is frequently invoked to describe droughts that develop rapidly over a relatively short timescale. Despite extensive and growing research on flash drought processes, predictability, and trends, there is still no standard quantitative definition that encompasses all flash drought characteristics and pathways. Instead, diverse definitions have been proposed, supporting wide-ranging studies of flash drought but creating the potential for confusion as to what the term means and how to characterize it. Use of different definitions might also lead to different conclusions regarding flash drought frequency, predictability, and trends under climate change. In this study, we compared five …

Unsupervised Data Mining Technique For Clustering Library In Indonesia, Robbi Rahim, Joseph Teguh Santoso, Sri Jumini, Gita Widi Bhawika, Daniel Susilo, Danny Wibowo

Library Philosophy and Practice (e-journal)

Organizing school libraries not only keeps library materials, but helps students and teachers in completing tasks in the teaching process so that national development goals are in order to improve community welfare by producing quality and competitive human resources. The purpose of this study is to analyze the Unsupervised Learning technique in conducting cluster mapping of the number of libraries at education levels in Indonesia. The data source was obtained from the Ministry of Education and Culture which was processed by the Central Statistics Agency (abbreviated as BPS) with url: bps.go.id/. The data consisted of 34 records where the attribute …

Modeling The Release And Spreading Of Permanganate From Aerated Slow-Release Oxidants In A Laboratory Flow Tank, Ann Kambhu, Yusong Li, Troy E. Gilmore, Steve D. Comfort

School of Natural Resources: Faculty Publications

Aerated, slow-release oxidants are a relatively new technology for treating contaminated aquifers. A critical need for advancing this technology is developing a reliable method for predicting the radius of influence (ROI) around each drive point. In this work, we report a series of laboratory flow tank experiments and numerical modeling efforts designed to predict the release and spreading of permanganate from aerated oxidant candles (oxidant-wax composites). To mimic the design of the oxidant delivery system used in the field, a double screen was used in a series of flow tank experiments where the oxidant was placed inside the inner screen …

Symbolic Rees Algebras, Eloísa Grifo, Alexandra Seceleanu

Department of Mathematics: Faculty Publications

We survey old and new approaches to the study of symbolic powers of ideals. Our focus is on the symbolic Rees algebra of an ideal, viewed both as a tool to investigate its symbolic powers and as a source of challenging problems in its own right. We provide an invitation to this area of investigation by stating several open questions.

Magnetic And Electron Transport Properties Of Co2Si Nanomagnets, Balamurugan Balasubramanian, Tom A. George, Priyanka Manchanda, Rabindra Pahari, Ahsan Ullah, Ralph Skomski, David J. Sellmyer

Department of Physics and Astronomy: Faculty Publications

Magnetotransport and ferromagnetism in thin films of Co₂Si nanoclusters are investigated experimentally and theoretically. The nanoclusters are fabricated by an inert-gas condensation-type cluster-deposition method and have an average size of 11.3 nm. Unlike the bulk Co₂Si that exhibits a very weak net magnetic moment only below 10 K, the nanoclusters exhibit room-temperature ferromagnetism with a substantial saturation magnetization. Key features of the system are its closeness to the Stoner transition, magnetic moments induced by spin polarization starting from surface atoms, and nonuniaxial anisotropy associated with the orthorhombic crystal structure of Co₂Si. A method is …

Two-Dimensional Antiferroelectric Tunnel Junction, Jun Ding, Ding-Fu Shao, Ming Li, Li-Wei Wen, Evgeny Y. Tsymbal

Department of Physics and Astronomy: Faculty Publications

Ferroelectric tunnel junctions (FTJs), which consist of two metal electrodes separated by a thin ferroelectric barrier, have recently aroused significant interest for technological applications as nanoscale resistive switching devices. So far, most existing FTJs have been based on perovskite-oxide barrier layers. The recent discovery of the two-dimensional (2D) van der Waals ferroelectric materials opens a new route to realize tunnel junctions with new functionalities and nm-scale dimensions. Because of the weak coupling between the atomic layers in these materials, the relative dipole alignment between them can be controlled by applied voltage. This allows transitions between ferroelectric and antiferroelectric orderings, resulting …

A Reimagining Of The Chacoan World, Larry Benson, Richard W. Loose

United States Geological Survey: Staff Publications

A new paradigm of the Chacoan world is presented, wherein Chaco Canyon is considered to be a mostly unoccupied architectural complex that functioned primarily as a pilgrimage destination. Chaco was the political, religious, and social focal point of people living in outlying regions. The resident population of the Canyon consisted of a small number of caretakers, charged with maintaining great house structures, food supplies, and their ceremonial contents. Chacoan chiefdoms were mostly located in large, well-watered, agriculturally-based communities situated at the base of mountains that ring the San Juan Basin, e.g., the Chuskas. Chiefly elites lived year-round in those areas, …

Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos

Department of Electrical and Computer Engineering: Faculty Publications

The emerging field of plasmonics can lead to enhanced light-matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit …

Anisotropic Dielectric Functions, Band-To-Band Transitions, And Critical Points In Α-Ga2O3, Matthew J. Hilfiker, Rafal Korlacki, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Ufuk Kilic, Megan Stokey, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We use a combined generalized spectroscopic ellipsometry and density functional theory approach to determine and analyze the anisotropic dielectric functions of an α-Ga₂O₃ thin film. The sample is grown epitaxially by plasma-assisted molecular beam epitaxy on m-plane sapphire. Generalized spectroscopic ellipsometry data from multiple sample azimuths in the spectral range from 0.73 eV to 8.75 eV are simultaneously analyzed. Density functional theory is used to calculate the valence and conduction band structure. We identify, for the indirect-bandgap material, two direct band-to-band transitions with M₀-type van Hove singularities for polarization perpendicular to the c axis, …

Could Energy Equilibrium And Greenhouse Gas Emissions In Agroecosystems Play A Key Role In Crop Replacement? A Case Study In Orange And Kiwi Orchards, Anastasios Mazis, Vassilis Litskas, Dimitrios P. Platis, Georgios .. Menexes, Christos D. Anagnostopoulos, Aggeliki Tsaboula, Andreas P. Mamolos, Kiriaki L. Kalburtji

School of Natural Resources: Faculty Publications

The development of agriculture is linked to energy resources. Consequently, energy analysis in agroecosystems could be a useful tool for monitoring some measures in the agricultural sector to mitigate greenhouse gas emissions. The objectives of this study were to (a) evaluate differences of energy indices in orange and kiwi orchards, and (b) point out whether inputs, outputs, efficiency, productivity, and carbon footprint can play a key role in crop replacement. Proportional stratified random sampling was used to select 26 orchards (10 oranges, 16 kiwis) from the Prefecture of Arta, western Greece, during 2015 and 2016. Univariate statistical methods were combined …

Protocol For Monitoring Aquatic Invertebrates Of Small Streams In The Heartland Inventory & Monitoring Network, Version 2.1, David E. Bowles, Michael H. Williams, Hope R. Dodd, Lloyd W. Morrison, Janice A. Hinsey, J. Tyler Cribbs, Gareth A. Rowell, Michael D. Debecker, Jennifer L. Haack-Gaynor, Jeffrey M. Williams

United States National Park Service: Publications

Executive Summary

The Heartland Inventory and Monitoring Network (HTLN) is a component of the National Park Service’s (NPS) strategy to improve park management through greater reliance on scientific information. The purposes of this program are to design and implement long-term ecological monitoring and provide information for park managers to evaluate the integrity of park ecosystems and better understand ecosystem processes. Concerns over declining surface water quality have led to the development of various monitoring approaches to assess stream water quality. Freshwater streams in network parks are threatened by numerous stressors, most of which originate outside park boundaries. Stream condition and …

Chiral Spin Textures In Amorphous Iron–Germanium Thick Films, Robert Streubel, D. Simca Bouma, Frank Bruni, Xiaoqian Chen, Peter Ercius, Jim Ciston, Alpha T. N'Diaye, Sujoy Roy, Steve D. Kevan, Peter Fischer, Frances Hellman

Robert Streubel Papers

Topological solitary fields, such as magnetic and polar skyrmions, are envisioned to revolutionize microelectronics. These configurations have been stabilized in solid-state materials with a global inversion symmetry breaking, which translates in magnetic materials into a vector spin exchange known as the Dzyaloshinskii–Moriya interaction (DMI), as well as spin chirality selection and isotropic solitons. This work reports experimental evidence of 3D chiral spin textures, such as helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe–Ge thick films. These results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems …

Symbolic Rees Algebras, Eloísa Grifo, Alexandra Seceleanu

Department of Mathematics: Faculty Publications

We survey old and new approaches to the study of symbolic powers of ideals. Our focus is on the symbolic Rees algebra of an ideal, viewed both as a tool to investigate its symbolic powers and as a source of challenging problems in its own right. We provide an invitation to this area of investigation by stating several open questions.

Ferromagnetic Liquid Droplets With Adjustable Magnetic Properties, Xuefei Wu, Robert Streubel, Xubo Liu, Paul Y. Kim, Yu Chai, Qin Hu, Dong Wang, Peter Fischer, Thomas P. Russell

Department of Physics and Astronomy: Faculty Publications

The assembly and jamming of magnetic nanoparticles (NPs) at liquid–liquid interfaces is a versatile platform to endow structured liquid droplets with a magnetization, i.e., producing ferromagnetic liquid droplets (FMLDs). Here, we use hydrodynamics experiments to probe how the magnetization of FMLDs and their response to external stimuli can be tuned by chemical, structural, and magnetic means. The remanent magnetization stems from magnetic NPs jammed at the liquid–liquid interface and dispersed NPs magneto-statically coupled to the interface. FMLDs form even at low concentrations of magnetic NPs when mixing nonmagnetic and magnetic NPs, since the underlying magnetic dipole-driven clustering of magnetic NP-surfactants …

Nebraska Statewide Groundwater-Level Monitoring Report 2020, Aaron R. Young, Mark E. Burbach, Leslie M. Howard, Sue Olafsen Lackey, Robert Matthew Joeckel

Conservation and Survey Division

The term “groundwater” has come to be all but synonymous with Nebraska. Nearly three-quarters of the total volume of the High Plains Aquifer lies beneath the state. Groundwater maintains our streams, our ecosystems, our people, and our vitally important agricultural economy. Nebraska’s total groundwater resource is vast, yet it is also vulnerable to natural and anthropogenic changes, necessitating a long-term commitment to wise management through informed decision-making. Monitoring, studying, and reporting form the essential basis for such management and, ultimately, for meeting the myriad challenges presented by change.

Delineating Knowledge Domains In Scientific Domains In Scientific Literature Using Machine Learning (Ml), Abhay Maurya, Smarajit Paul Choudhury Mr., Kshitij Jaiswal Mr.

Library Philosophy and Practice (e-journal)

The recent years have witnessed an upsurge in the number of published documents. Organizations are showing an increased interest in text classification for effective use of the information. Manual procedures for text classification can be fruitful for a handful of documents, but the same lack in credibility when the number of documents increases besides being laborious and time-consuming. Text mining techniques facilitate assigning text strings to categories rendering the process of classification fast, accurate, and hence reliable. This paper classifies chemistry documents using machine learning and statistical methods. The procedure of text classification has been described in chronological order like …

Production Of Embryos And A Live Offspring Using Post Mortem Reproductive Material From Bison (Bison Bison Bison) Originating In Yellowstone National Park, Usa, Hayley M. Benham, Matthew P. Mccollum, Pauline Nol, Rebecca K. Frey, P. Ryan Clarke, Jack C. Rhyan, Jennifer P. Barfield

United States Department of Agriculture Wildlife Services: Staff Publications

Bison from Yellowstone National Park (YNP) have an important genetic history. As one of the few wild herds of bison with no evidence of cattle DNA introgression and a large enough population to maintain genetic diversity, they are considered a conservation priority for the species. Unfortunately, there is a high prevalence of the zoonotic disease brucellosis in the herd. Part of the management strategy for controlling the disease and herd size in YNP is to remove bison from the population during the winter migration out of the park. This interagency management cull provides an opportunity to collect a large number …

Surface Acoustic Waves Increase Magnetic Domain Wall Velocity, Anil Adhikari, S. Adenwalla

Department of Physics and Astronomy: Faculty Publications

Domain walls in magnetic thin films are being explored for memory applications and the speed at which they move has acquired increasing importance. Magnetic fields and currents have been shown to drive domain walls with speeds exceeding 500 m/s. We investigate another approach to increase domain wall velocities, using high frequency surface acoustic waves to create standing strain waves in a 3 micron wide strip of magnetic film with perpendicular anisotropy. Our measurements, at a resonant frequency of 248.8 MHz, indicate that domain wall velocities increase substantially, even at relatively low applied voltages. Our findings suggest that the strain wave …

Structure Retrieval In Liquid-Phase Electron Scattering, Jie Yang, J. Pedro F. Nunes, Kathryn Ledbetter, Elisa Biasin, Martin Centurion, Zhijiang Chen, Amy A. Cordones, Christopher Crissman, Daniel P. Deponte, Siegfried H. Glenzer, Ming Fu Lin, Mianzhen Mo, Conor D. Rankine, Xiaozhe Shen, Thomas J.A. Wolf, Xijie Wang

Martin Centurion Publications

Electron scattering on liquid samples has been enabled recently by the development of ultrathin liquid sheet technologies. The data treatment of liquid-phase electron scattering has been mostly reliant on methodologies developed for gas electron diffraction, in which theoretical inputs and empirical fittings are often needed to account for the atomic form factor and remove the inelastic scattering background. In this work, we present an alternative data treatment method that is able to retrieve the radial distribution of all the charged particle pairs without the need of either theoretical inputs or empirical fittings. The merits of this new method are illustrated …

Dispersal And Land Cover Contribute To Pseudorabies Virus Exposure In Invasive Wild Pigs, Felipe A. Hernandez, Amanda N. Carr, Michael P. Milleson, Hunter R. Merrill, Michael L. Avery, Brandon M. Parker, Cortney L. Pylant, James D. Austin, Samantha M. Wisely

United States Department of Agriculture Wildlife Services: Staff Publications

We investigated the landscape epidemiology of a globally distributed mammal, the wild pig (Sus scrofa), in Florida (U.S.), where it is considered an invasive species and reservoir to pathogens that impact the health of people, domestic animals, and wildlife. Specifically, we tested the hypothesis that two commonly cited factors in disease transmission, connectivity among populations and abundant resources, would increase the likelihood of exposure to both pseudorabies virus (PrV) and Brucella spp. (bacterial agent of brucellosis) in wild pigs across the Kissimmee Valley of Florida. Using DNA from 348 wild pigs and sera from 320 individuals at 24 sites, we …

Integrating Out New Fermions At One Loop, Andrei Angelescu, Peisi Huang

Department of Physics and Astronomy: Faculty Publications

We present the fermionic universal one-loop effective action obtained by integrating out heavy vector-like fermions at one loop using functional techniques. Even though previous approaches are able to handle integrating out heavy fermions with non-chiral interactions, i.e. vanishing γ⁵ interaction terms, the computations proceed in a tedious manner that obscures a physical interpretation. We show how directly tackling the fermionic functional determinant not only allows for a much simpler and transparent computation, but is also able to account for chiral interaction terms in a simple, algorithmic way. Finally, we apply the obtained results to integrate out at one loop …

Exploiting Common Senses: Sensory Ecology Meets Wildlife Conservation And Management, Laura K. Elmer, Christine L. Madliger, Daniel T. Blumstein, Chris K. Elvidge, Esteban Ernández-Juricic, Andrij Z. Horodysky, Nicholas S. Johnson, Liam P. Mcguire, Ronald R. Swaisgood, Steven J. Cooke

United States Geological Survey: Staff Publications

Multidisciplinary approaches to conservation and wildlife management are often effective in addressing complex, multi-factor problems. Emerging fields such as conservation physiology and conservation behaviour can provide innovative solutions and management strategies for target species and systems. Sensory ecology combines the study of ‘how animals acquire’ and process sensory stimuli from their environments, and the ecological and evolutionary significance of ‘how animals respond’ to this information. We review the benefits that sensory ecology can bring to wildlife conservation and management by discussing case studies across major taxa and sensory modalities. Conservation practices informed by a sensory ecology approach include the amelioration …

Valuation Of Drought Information: Understanding The Value Of The Us Drought Monitor In Land Management, Tingting Liu, Richard Krop, Tonya Haigh, Kelly Helm Smith, Mark D. Svoboda

Drought Mitigation Center: Faculty Publications

Droughts affect recreation and tourism, grazing, forests, and timber, and can have important indirect effects for the ecosystems and species that rely on water. Despite its importance, the effect of drought in the land management sector is less understood than in other water-intensive sectors, such as agriculture and public water supplies. This study presents the first-ever estimates of the economic valuation of the information provided by the U.S. Drought Monitor using the avoided cost method. These estimates are based on the time and labor saved by using the U.S. Drought Monitor rather than compiling drought-related information from other sources, or …

A Novel Strategy To Reconstruct Ndvi Time-Series With High Temporal Resolution From Modis Multi-Temporal Composite Products, Linglin Zeng, Brian Wardlow, Shun Hu, Xiang Zhang, Guoqing Zhou, Guozhang Peng, Daxiang Xiang, Rui Wang, Ran Meng, Weixiong Wu

Center for Advanced Land Management Information Technologies: Publications

Vegetation indices (VIs) data derived from satellite imageries play a vital role in land surface vegetation and dynamic monitoring. Due to the excessive noises (e.g., cloud cover, atmospheric contamination) in daily VI data, temporal compositing methods are commonly used to produce composite data to minimize the negative influence of noise over a given compositing time interval. However, VI time series with high temporal resolution were preferred by many applications such as vegetation phenology and land change detections. This study presents a novel strategy named DAVIR-MUTCOP (DAily Vegetation Index Reconstruction based on MUlti-Temporal COmposite Products) method for normalized difference vegetation index …

Influence Of Irrigation Drivers Using Boosted Regression Trees: Kansas High Plains, Susan E. Lamb, Erin M.K. Haacker, Samuel J. Smidt

Department of Earth and Atmospheric Sciences: Faculty Publications

Groundwater levels across parts of western Kansas have been declining at unsustainable rates due to pumping for agricultural irrigation despite water-saving efforts. Accelerating this decline is the complex agricultural landscape, consisting of both categorical (e.g., management boundaries) and numerical (e.g., crop prices) factors that drive irrigation decisions, making integrated water budget management a challenge. Furthermore, these factors frequently change through time, rendering management strategies outdated within relatively short time scales. This study uses boosted regression trees to simultaneously analyze categorical and numerical data against annual irrigation pumping to determine the relative influence of each factor on groundwater pumping across both …

Subsurface Structures Along Western Yucatan From Integrated Geophysical Analysis, Irina Filina, Lucas Hartford

Department of Earth and Atmospheric Sciences: Faculty Publications

Integration of seismic, gravity, and magnetic data revealed variations in crustal architecture along the Yucatan passive continental margin. The crust beneath the Yucatan salt basin is ~10 km thick and is primarily a lower continental crust. In contrast, the crust beneath the Campeche salt basin is thicker and comprises both the upper and the lower crustal layers. These variations in crustal architecture explain the strikingly different tectonic histories of these basins outlined by previous authors. The rifting of the Yucatan margin was associated with extensive magmatism expressed as voluminous igneous intrusions in the lower crust, one of which is manifested …

Structure Formation And Coupling Reactions Of Hexaphenylbenzene And Its Brominated Analog, Jacob D Teeter, Paulo S. Costa, Christoph Dobner, Mamun Sarker, Alexander Sinitskii, Axel Enders

Chemistry Department: Faculty Publications

The on-surface coupling of the prototypical precursor molecule for graphene nanoribbon synthesis, 6,11-dibromo-1,2,3,4-tetraphenyltriphenylene (C₄₂Br₂H₂₆, TPTP), and its non-brominated analog hexaphenylbenzene (C₄₂H₃₀, HPB), was investigated on coinage metal substrates as a function of thermal treatment. For HPB, which forms non-covalent 2D monolayers at room temperature, a thermally induced transition of the monolayer’s structure could be achieved by moderate annealing, which is likely driven by π-bond formation. It is found that the dibrominated carbon positions of TPTP do not guide the coupling if the growth occurs on a substrate at temperatures that …

Solar Panels: Are Aesthetics More Important Than The Environment?, Madison Kinkaid

Op-Eds from ENSC230 Energy and the Environment: Economics and Policies

Imagine you decide to install solar panels on your house. You want to do your part in combating the climate crisis as well as save your family money. You’ve done your research about which panels to get and exactly how to position them on your home. Then you find out that your neighborhood doesn’t allow solar panels because someone decades ago decided they weren’t aesthetically pleasing.