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Articles 181 - 210 of 23960

Full-Text Articles in Physical Sciences and Mathematics

A Description Of The Grassland Communities Of The Wildcat Hills Region Of Northwestern Nebraska Including Scotts Bluff National Monument And Rare Plant Survey Of The Wildcat Hills Region Of Northwestern Nebraska, Volume Ii, Terri Hildebrand, Steven B. Rolfsmeier Aug 2023

A Description Of The Grassland Communities Of The Wildcat Hills Region Of Northwestern Nebraska Including Scotts Bluff National Monument And Rare Plant Survey Of The Wildcat Hills Region Of Northwestern Nebraska, Volume Ii, Terri Hildebrand, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This study resulted from a Cooperative Agreement between Nebraska Game and Parks Commission and the National Park Service (NPS), with funding provided by the Natural Resource Preservation Program of the NPS. Scotts Bluff National Monument was seeking to characterize the native grassland communities of the Wildcat Hills region in order to develop species composition models for prairie restoration of disturbed lands at the monument. Nebraska Game and Parks Commission needed similar information to refine community classification for the Wildcat Hills region, and to update rare plant species inventories. This report includes a description of the grassland communities and a rare …


Vegetative Sampling Of The Wildcat Hills Region Of Northwestern Nebraska Including Scotts Bluff National Monument And Rare Plant Survey Of The Wildcat Hills Region Of Northwestern Nebraska, A Final Report To: Nebraska Game And Parks Commission, Terri Hildebrand, Steven B. Rolfsmeier Aug 2023

Vegetative Sampling Of The Wildcat Hills Region Of Northwestern Nebraska Including Scotts Bluff National Monument And Rare Plant Survey Of The Wildcat Hills Region Of Northwestern Nebraska, A Final Report To: Nebraska Game And Parks Commission, Terri Hildebrand, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The Wildcat Hills region of northwestern Nebraska is a ridge extending westerly from Chimney Rock in Morrill county to west of Kiowa Creek in central Scotts Bluff county and southerly into the northernmost portions of Banner county (Fig. 1). Much of the expanse is fronted along its northern portion by the North Platte River and US Highway 26. Also included within the study area are the federal lands of Scotts Bluff National Monument and Chimney Rock National Historic Site. Two large portions of state lands, Wildcat Hills State Recreation Area and Buffalo Creek Wildlife Management Area, are located just easterly …


White-Tailed Deer (Odocoileus Virginianus) Fawn Survival And The Influence Of Landscape Characteristics On Fawn Predation Risk In The Southern Appalachian Mountains, Usa, Adam C. Edge, Jacalyn P. Rosenberger, Cheyenne J. Yates, Andrew R. Little, Charlie H. Killmaster, Kristina L. Johannsen, David A. Osborn, John C. Kilgo, Karl V. Miller, Gino J. D’Angelo Aug 2023

White-Tailed Deer (Odocoileus Virginianus) Fawn Survival And The Influence Of Landscape Characteristics On Fawn Predation Risk In The Southern Appalachian Mountains, Usa, Adam C. Edge, Jacalyn P. Rosenberger, Cheyenne J. Yates, Andrew R. Little, Charlie H. Killmaster, Kristina L. Johannsen, David A. Osborn, John C. Kilgo, Karl V. Miller, Gino J. D’Angelo

School of Natural Resources: Faculty Publications

In the Southern Appalachian region of the United States, harvest data has indicated the occurrence of low deer densities while exposing a trend of declining white-tailed deer (Odocoileus virginianus) populations over the past several decades in northern Georgia. A triumvirate of increasing fawn predator populations reside in the Southern Appalachian Mountains including coyotes (Canis latrans), black bears (Ursus americanus) and bobcats (Lynx rufus). This region is also characterized by a homogenous landscape composed of mature forests and sparse understory vegetation, likely lacking adequate cover to offer fawns refugia from predators. Our objectives …


Freshwater And Saline Flood Plain Wetlands Of The North Platte River - Sources And Seasonal Dynamics: Kiowa Wildlife Management Area, Morrill, Ne, Anne M. Matherne Aug 2023

Freshwater And Saline Flood Plain Wetlands Of The North Platte River - Sources And Seasonal Dynamics: Kiowa Wildlife Management Area, Morrill, Ne, Anne M. Matherne

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The Kiowa Wildlife Management Area (WMA), a 1 mi² wetland and upland on the North Platte River, was acquired by the Nebraska Game and Parks Commission (NGPC) in 1993. The WMA comprises two distinct wetland types, alkaline and freshwater, both of which provide important wildlife habitat. It was the goal of this project to understand the hydrology controlling the development and maintenance of these wetlands in order to anticipate the affect of management strategies on the wetland complex. The study was designed to develop a comprehensive picture of the hydrogeology of both the fresh and alkaline portions of the WMA, …


Willa Cather Ecological Prairie: An Ecological Overview, Harold G. Nagel Aug 2023

Willa Cather Ecological Prairie: An Ecological Overview, Harold G. Nagel

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report includes data gathered on the ecology of a 610 acre mixed grass prairie in south-central Nebraska over a two year period.

An attempt was made to identify as many of the plant and animal species present and to determine density and standing crop biomass wherever possible, under the time and financial constraints present. Few attempts have been made to develop complete species checklists for both animals and plants in prairies. The data collected are considered baseline conditions against which comparisons can be made after a management plan is carried out.

This study of Cather Prairie had several objectives. …


The Flora Of The Oak-Wooded Drainages At The Timber Point Area, Southeastern Butler County, Nebraska, Steven B. Rolfsmeier Aug 2023

The Flora Of The Oak-Wooded Drainages At The Timber Point Area, Southeastern Butler County, Nebraska, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The Timber Point Area is a 160-acre recreational/wildlife area occupying to S½ of the SW¼ sec. 22 and the adjacent N½ of the NW¼ sec. 27, T14N R4E. The area is located in the loess-mantled glacial-till hills of southeast Nebraska not far from the terminal moraine of the Pre-Illinoian glacial sheet, one mile south and two miles east of the present town of Brainard. The uplands at Timber Point were apparently in pasture prior to purchase by the NRD, with some cultivated fields occupying the lower ground along a stream valley which southwest to northeast through the property. This small …


The Flora Of Two Oak Drainages At The Red Cedar Area, Southwestern Saunders County, Nebraska, Steven B. Rolfsmeier Aug 2023

The Flora Of Two Oak Drainages At The Red Cedar Area, Southwestern Saunders County, Nebraska, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The Red Cedar Area is a 175 acre recreational/wildlife area occupying the SE¼ sec. 20, T14N R5E and a small portion of sec. 29 directly to the south. The area is located in the glacial-till hills of southeast Nebraska ca 5 mi. north and 2 mi. west of Valpraiso. The bulk of the area was cultivated farmland prior to purchase by the NRD, and nearly all upland areas here were cultivated cropland, save for some steep oak-wooded drainages on the east side of Hunter’s Slough, which ran northwest to southeast through the property. The creek was dammed after NRD purchase …


The Vascular Plants Of The Woodlands Of South Table Creek In The Vicinity Of The National Arbor Day Center, Nebraska City, Nebraska, Steven B. Rolfsmeier Aug 2023

The Vascular Plants Of The Woodlands Of South Table Creek In The Vicinity Of The National Arbor Day Center, Nebraska City, Nebraska, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

The objective of this study is to describe the composition of the vascular plant flora of a three-quarter mile stretch of woodland along South Table Creek managed by the National Arbor Day Foundation in Nebraska City. This 50-60 acre woodland is representative of the many small tributaries of the Missouri River in southeastern Nebraska, and may represent the only natural “preserve” of native forest on the west side of the Missouri River between Fontenelle Forest and Indian Cave State Park. All naturally-occurring species encountered in this study are listed alphabetically by family at the end of this paper, and a …


The Flora Of Meadowlark Prairie, Northeastern Seward County, Nebraska, Steven B. Rolfsmeier Aug 2023

The Flora Of Meadowlark Prairie, Northeastern Seward County, Nebraska, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report is on the flora of the Meadowlark Prairie. The prairie is an approximately 7 acre remnant of virgin tall-grass prairie in extreme northeastern Seward County, Nebraska. The remnant is triangular in shape and lies on a gentle southeast-facing slope with a total relief of 50 ft., along the east boundary of the Meadowlark Recreation Area. The prairie is surrounded on the east side by a small brome-infested prairie remnant and cultivated field off the NRD property, and on the remaining sides by formerly cultivated fields now seeded to native warm-season grasses. Soils in the area are primarily derived …


The Flora And Plant Communities Of The Ceresco Saline Basins, Southern Saunders County, Nebraska, Steven B. Rolfsmeier Aug 2023

The Flora And Plant Communities Of The Ceresco Saline Basins, Southern Saunders County, Nebraska, Steven B. Rolfsmeier

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report is on the flora and plant communities of the Ceresco Saline Basins. The basins are along Rock Creek east of Ceresco and represent the northernmost representatives of the “eastern saline marsh” community in Nebraska. Eastern saline marshland is mostly restricted to the Salt Creek drainage in northern and central Lancaster County, though the Ceresco basins extend a mile or more north into Saunders County in the floodplain of Rock Creek. Some of the wetland in this area is currently under management of the Nebraska Game and Parks Commission, while some of the northernmost portions of the basins are …


An Improved Source Of Spin-Polarized Electrons Based On Spin Exchange In Optically Pumped Rubidium Vapor, K. J. Ahrendsen, Kenneth Wayne Trantham, D. Tupa, T. J. Gay Aug 2023

An Improved Source Of Spin-Polarized Electrons Based On Spin Exchange In Optically Pumped Rubidium Vapor, K. J. Ahrendsen, Kenneth Wayne Trantham, D. Tupa, T. J. Gay

Department of Physics and Astronomy: Faculty Publications

We have improved a polarized electron source in which unpolarized electrons undergo collisions with a mixture of buffer gas molecules and optically spin-polarized Rb atoms. With a nitrogen buffer gas, the source reliably provides spin polarization between 15% and 25% with beam currents >4 μA. Vacuum pump upgrades mitigate problems caused by denatured diffusion pump oil, leading to longer run times. A new differential pumping scheme allows the use of higher buffer gas pressures up to 800 mTorr. With a new optics layout, the Rb polarization is continuously monitored by a probe laser and improved pump laser power provides more …


Search For Magnetoelectric Monopole Response In Cr2O3 Powder, Syed Qamar Abbas Shah, Ather Mahmood, Arun Parthasarathy, Christian H. Binek Aug 2023

Search For Magnetoelectric Monopole Response In Cr2O3 Powder, Syed Qamar Abbas Shah, Ather Mahmood, Arun Parthasarathy, Christian H. Binek

Department of Physics and Astronomy: Faculty Publications

Powder samples have been suggested as a pathway to fabricate isotropic magnetoelectric (ME) materials which effectively only have a pseudoscalar or monopole ME response. We demonstrate that random distribution of ME grains alone does not warrant isotropic ME response because the activation of a nonvanishing ME response requires a ME field cooling protocol which tends to induce preferred axes.We investigate the evolution of ME susceptibility in powder chromia samples for various ME field cooling protocols both theoretically and experimentally. In particular, we work out the theoretical expressions for ME susceptibility for powder chromia in the framework of statistical mechanics where …


The Patchwork Governance Of Ecologically Available Water: A Case Study In The Upper Missouri Headwaters, Montana, United States, Amanda E. Cravens, Julia B. Goolsby, Theresa Jedd, Deborah J. Bathke, Shelley Crausbay, Ashley E. Cooper, Jason Dunham, Tonya Haigh, Kimberly R. Hall, Michael J. Hayes, Jamie Mcevoy, Rebecca L. Nelson, Markéta Poděbradská, Aaron Ramirez, Elliot Wickham, Dionne Zoanni Aug 2023

The Patchwork Governance Of Ecologically Available Water: A Case Study In The Upper Missouri Headwaters, Montana, United States, Amanda E. Cravens, Julia B. Goolsby, Theresa Jedd, Deborah J. Bathke, Shelley Crausbay, Ashley E. Cooper, Jason Dunham, Tonya Haigh, Kimberly R. Hall, Michael J. Hayes, Jamie Mcevoy, Rebecca L. Nelson, Markéta Poděbradská, Aaron Ramirez, Elliot Wickham, Dionne Zoanni

Drought Mitigation Center: Faculty Publications

Institutional authority and responsibility for allocating water to ecosystems (“ecologically available water” [EAW]) is spread across local, state, and federal agencies, which operate under a range of statutes, mandates, and planning processes. We use a case study of the Upper Missouri Headwaters Basin in southwestern Montana, United States, to illustrate this fragmented institutional landscape. Our goals are to (a) describe the patchwork of agencies and institutional actors whose intersecting authorities and actions influence the EAW in the study basin; (b) describe the range of governance mechanisms these agencies use, including laws, policies, administrative programs, and planning processes; and (c) assess …


A Sensitivity Study Of Triboson Production Processes To Dimension-6 Eft Operators At The Lhc, R. Bellan, S. Bhattacharya, G. Boldrini, F. Cetorelli, P. Govoni, A. Massironi, A. Mecca, C. Tarricone, A. Vagnerini Aug 2023

A Sensitivity Study Of Triboson Production Processes To Dimension-6 Eft Operators At The Lhc, R. Bellan, S. Bhattacharya, G. Boldrini, F. Cetorelli, P. Govoni, A. Massironi, A. Mecca, C. Tarricone, A. Vagnerini

Department of Physics and Astronomy: Faculty Publications

We present the first parton-level study of anomalous effects in triboson production in both fully and semi-leptonic channels in proton-proton collisions at 13TeV at the Large Hadron Collider (LHC). The sensitivity to anomalies induced by a minimal set of bosonic dimension-6 operators from the Warsaw basis is evaluated with specific analyses for each final state. A likelihood-based strategy is employed to assess the most sensitive kinematic observables per channel, where the contribution of Effective Field Theory operators is parameterized at either the linear or quadratic level. The impact of the mutual interference terms of pairs of operators on the sensitivity …


A Search For Decays Of The Higgs Boson To Invisible Particles In Events With A Top-Antitop Quark Pair Or A Vector Boson In Proton-Proton Collisions At √S = 13 Tev, Armen R. Tumasyan Aug 2023

A Search For Decays Of The Higgs Boson To Invisible Particles In Events With A Top-Antitop Quark Pair Or A Vector Boson In Proton-Proton Collisions At √S = 13 Tev, Armen R. Tumasyan

Department of Physics and Astronomy: Faculty Publications

The first search for nonresonant production of Higgs boson pairs (HH) with one H decaying into four leptons and the other into a pair of b quarks is presented, using proton-proton collisions recorded at a center-of-mass energy of √s = 13 TeV by the CMS experiment. The analyzed data correspond to an integrated luminosity of 138 fb−1. A 95% confidence level upper limit of 32.4 is set on the signal strength modifier μ, defined as the ratio of the observed HH production rate in the HH → ZZ*bb → 4ℓbb decay channel to the standard model …


Initial Experience With An Electron Flash Research Extension (Flex) For The Clinac System, Kyuhak Oh, Kyle J. Gallagher, Megan Hyun, Diane Schott, Sarah Wisnoskie, Yu Lei, Samuel Hendley, Jeffrey Wong, Shuo Wang, Brendan Graff, Christopher Jenkins, Frank Rutar, Md Ahmed, Joshua Mcneur, Jeffrey Taylor, Marty Schmidt, Lasitha Senadheera, Wendy Smith, Subodh M. Lele, Ran Dai, Dong Jianghu (James), Y Yan, Su-Min Zhou Aug 2023

Initial Experience With An Electron Flash Research Extension (Flex) For The Clinac System, Kyuhak Oh, Kyle J. Gallagher, Megan Hyun, Diane Schott, Sarah Wisnoskie, Yu Lei, Samuel Hendley, Jeffrey Wong, Shuo Wang, Brendan Graff, Christopher Jenkins, Frank Rutar, Md Ahmed, Joshua Mcneur, Jeffrey Taylor, Marty Schmidt, Lasitha Senadheera, Wendy Smith, Subodh M. Lele, Ran Dai, Dong Jianghu (James), Y Yan, Su-Min Zhou

Department of Physics and Astronomy: Faculty Publications

Purpose: Radiotherapy delivered at ultra-high-dose-rates (≥40 Gy/s), that is, FLASH, has the potential to effectively widen the therapeutic window and considerably improve the care of cancer patients. The underlying mechanism of the FLASH effect is not well understood, and commercial systems capable of delivering such dose rates are scarce. The purpose of this study was to perform the initial acceptance and commissioning tests of an electron FLASH research product for preclinical studies.

Methods: A linear accelerator (Clinac 23EX) was modified to include a nonclinical FLASH research extension (the Clinac-FLEX system) by Varian, a Siemens Healthineers company (Palo Alto, …


Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston Aug 2023

Introducing High School Biology Students To Biochemistry With A Short, Content-Oriented Module, Archer Harrold, Allison Cruikshank, Bryan Penas, Rebecca Roston

Chemistry Department: Faculty Publications

Many STEM disciplines are underrepresented to High School students. This is problematic as many students' decisions for college are shaped by their experiences and achievements in high school. Short content-oriented modules have been shown to encourage science identity and otherwise benefit the students' learning. Following the ASBMB's outreach protocol, we developed a short content-oriented module aimed at a high school biology classroom. Students interacted with 3D models of DNA and transcription factors while exploring structure–function relationships and introductory biochemistry topics. The high school teacher was impressed with the students' response to the module, specifically the ease with which students learned, …


A Variational Theory For Integral Functionals Involving Finite-Horizon Fractional Gradients, Javier Cueto, Carolin Carolin, Hidde Schönberger Aug 2023

A Variational Theory For Integral Functionals Involving Finite-Horizon Fractional Gradients, Javier Cueto, Carolin Carolin, Hidde Schönberger

Department of Mathematics: Faculty Publications

The center of interest in this work are variational problems with integral functionals depending on nonlocal gradients with finite horizon that correspond to truncated versions of the Riesz fractional gradient. We contribute several new aspects to both the existence theory of these problems and the study of their asymptotic behavior. Our overall proof strategy builds on finding suitable translation operators that allow to switch between the three types of gradients: classical, fractional, and nonlocal. These provide useful technical tools for transferring results from one setting to the other. Based on this approach, we show that quasiconvexity, which is the natural …


Evaluation Of Native Plant Communities On Nebraska Game And Parks Commission State Parks, Robert F. Steinauer Aug 2023

Evaluation Of Native Plant Communities On Nebraska Game And Parks Commission State Parks, Robert F. Steinauer

Nebraska Game and Parks Commission: White Papers, Conference Presentations, and Manuscripts

This report evaluates the Native Plant Communities on Nebraska Game and Parks Commission State Parks East Region, also known as Region 3, which includes much of northeast and extreme eastern Nebraska, including portions of the lower Niobrara, Elkhorn and Platte Rivers and nearly the entire east border formed by the Missouri River. Fifteen state-listed threatened and endangered species have been recorded within the boundaries of Region 3 within the last twenty years. Several of these occupy habitats within major river channels.

Surveyed areas which contained habitat for legally protected species include Dead Timber State Recreation Area, Indian Cave State Park, …


Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson Aug 2023

Changes In An Enzyme Ensemble During Catalysis Observed By High Resolution Xfel Crystallography, Nathan J. Smith, Medhanjali Dasgupta, David C. Wych, Cole Dolamore, Raymond G. Sierra, Stella Lisova, Darya Marchany-Rivera, Aina E. Cohen, Sébastien Boutet, Mark S. Hunter, Christopher Kupitz, Frédéric Poitevin, Frank R. Moss Iii, Aaron S. Brewster, Nicholas K. Sauter, Iris D. Young, Alexander M. Wolff, Virendra K. Tiwari, Nivesh Kumar, David B. Berkowitz, Ryan G. Hadt, Michael C. Thompson, Alec H. Follmer, Mark A. Wilson

Chemistry Department: Faculty Publications

Enzymes populate ensembles of structures with intrinsically different catalytic proficiencies that are difficult to experimentally characterize. We use time-resolved mix-and-inject serial crystallography (MISC) at an X-ray free electron laser (XFEL) to observe catalysis in a designed mutant (G150T) isocyanide hydratase (ICH) enzyme that enhances sampling of important minor conformations. The active site exists in a mixture of conformations and formation of the thioimidate catalytic intermediate selects for catalytically competent substates. A prior proposal for active site cysteine charge-coupled conformational changes in ICH is validated by determining structures of the enzyme over a range of pH values. A combination of large …


Magnetic Nanodoping: Atomic Control Of Spin States In Cobalt Doped Silver Clusters, Vicente Zamudio-Bayer, Konstantin Hirsch, Lei Ma, Kobe De Knijf, X. S. Xu, Arkadiusz Ławicki, Akira Terasaki, Piero Ferrari, Bernd Von Issendorff, Peter Lievens, Walt A. De Heer, J. Tobias Lau, Ewald Janssens Aug 2023

Magnetic Nanodoping: Atomic Control Of Spin States In Cobalt Doped Silver Clusters, Vicente Zamudio-Bayer, Konstantin Hirsch, Lei Ma, Kobe De Knijf, X. S. Xu, Arkadiusz Ławicki, Akira Terasaki, Piero Ferrari, Bernd Von Issendorff, Peter Lievens, Walt A. De Heer, J. Tobias Lau, Ewald Janssens

Department of Physics and Astronomy: Faculty Publications

The interaction of magnetic dopants with delocalized electron states can result in interesting many-body physics. Here, the magnetic properties of neutral and charged finite silver metal host clusters with a magnetic cobalt atom impurity were investigated experimentally by exploiting the complementary methods of Stern- Gerlach molecular beam deflection and x-ray magnetic circular dichroism spectroscopy and are accompanied by density functional theory calculations and charge transfer multiplet simulations. The influence of the number of valence electrons and the consequences of impurity encapsulation were addressed in free size-selected, singly cobalt-doped silver clusters CoAg0,n+ (n = 2–15). Encapsulation of the …


A Search For Chiral Asymmetry In Secondary Electron Emission From Cysteine Induced By Longitudinally Polarized Electrons, K. J. Ahrendsen, Kenneth Wayne Trantham, D. Tupa, T. J. Gay Aug 2023

A Search For Chiral Asymmetry In Secondary Electron Emission From Cysteine Induced By Longitudinally Polarized Electrons, K. J. Ahrendsen, Kenneth Wayne Trantham, D. Tupa, T. J. Gay

Department of Physics and Astronomy: Faculty Publications

We performed experiments searching for chirality-dependent secondary electron emission for a 141 eV longitudinally spin-polarized electron beam incident on a thick solid cysteine target. We determined the secondary electron yield by measuring the positive current produced when the cysteine target was negatively biased. No spin-dependent effects to a level of 10−3 were found for the secondary electron emission yield.


On The Boundary Of The Cosmos, Daniel Linford Aug 2023

On The Boundary Of The Cosmos, Daniel Linford

Chemistry Department: Faculty Publications

Intuitively, the totality of physical reality – the Cosmos – has a beginning only if (i) all parts of the Cosmos agree on the direction of time (the Direction Condition) and (ii) there is a boundary to the past of all non-initial spacetime points such that there are no spacetime points to the past of the boundary (the Boundary Condition). Following a distinction previously introduced by J. Brian Pitts, the Boundary Condition can be conceived of in two distinct ways: either topologically, i.e., in terms of a closed boundary, or metrically, i.e., in terms of the Cosmos having a finite …


The Devil You Know And The Devil You Don’T: Current Status And Challenges Of Bovine Tuberculosis Eradication In The United States, Daniel J. O'Brien, Tyler C. Thacker, Liliana C.M. Salvador, Anthony G. Duffiney, Suelee Robbe‑Austerman, Mark S. Camacho, Jason E. Lombard, Mitchell V. Palmer Aug 2023

The Devil You Know And The Devil You Don’T: Current Status And Challenges Of Bovine Tuberculosis Eradication In The United States, Daniel J. O'Brien, Tyler C. Thacker, Liliana C.M. Salvador, Anthony G. Duffiney, Suelee Robbe‑Austerman, Mark S. Camacho, Jason E. Lombard, Mitchell V. Palmer

USDA Wildlife Services: Staff Publications

Having entered into its second century, the eradication program for bovine tuberculosis (bTB, caused by Mycobacterium bovis) in the United States of America occupies a position both enviable and daunting. Excepting four counties in Michigan comprising only 6109 km2 (0.06% of US land area) classified as Modified Accredited, as of April 2022 the entire country was considered Accredited Free of bTB by the US Department of Agriculture for cattle and bison. On the surface, the now well-described circumstances of endemic bTB in Michigan, where white-tailed deer (Odocoileus virginianus) serve as a free-ranging wildlife maintenance host, may appear to be …


Topological Hall Effect In Particulate Magnetic Nanostructure, Ahsan Ullah Aug 2023

Topological Hall Effect In Particulate Magnetic Nanostructure, Ahsan Ullah

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Conduction electrons change their spin direction due to the exchange interaction with the lattice spins. Ideally, the spins of the conduction electrons follow the atomic spin adiabatically, so that spins like S1, S2, and S3 can be interpreted as time-ordered sequences t1 < t2 < t3. Such spin sequences yield a quantum-mechanical phase factor in the wave function,  →ei, where  is known as the Berry phase. The corresponding spin rotation translates into a Berry curvature and an emergent magnetic field and subsequently, Hall-effect contribution known as the topological Hall-effect. This dissertation explores topological Hall-effect in particulate magnets, where noncollinear spins are stabilized by competition between different magnetic interactions. The topologically non-trivial spin textures in these nanostructures are flower states, curling states, vortex, and magnetic bubbles, which give rise to topological Hall-effect and have finite spin chirality and Skyrmion number Q. Topological Hall-effect is investigated in noninteracting nanoparticles, exchanges coupled centrosymmetric nanoparticles, exchanges coupled non-centrosymmetric nanoparticles which possess Dzyaloshinskii-Moriya interaction (DMI), and exchanged coupled Hard and soft magnetic films. Micromagnetic modeling, simulations, analytical calculations, and experimental methods are used to determine topological Hall-effect. In very small noninteracting nanoparticles, the reverse magnetic fields enhance Q due to the flower state until the reversal occurs, whereas, for particles with a radius greater than coherence radius, the Q jumps to a larger value at the nucleation field representing the curling state. The comparisons of magnetization patterns between experimental and computed magnetic force microscopy (MFM) measurements show the presence of spin chirality. Magnetic and Hall-effect measurements identify topological Hall-effect in the exchange-coupled Co and CoSi-nanoparticle films. The origin of the topological Hall-effect namely, the chiral domains with domain-wall chirality quantified by an integer skyrmion number in Co and chiral spins with partial skyrmion number in CoSi. These spin structures are different from the Skyrmions due to DMI in B-20 crystals and multilayered thin films with Cnv symmetry. In these films THE caused by cooperative magnetization reversal in the exchange-coupled Co-nanoparticles and peripheral chiral spin textures in CoSi-nanoparticles.

Advisor: Xiaoshan Xu


Functional Connectivity Varies Across Scales In A Fragmented Landscape, Kate I. T. Bird, Daniel R. Uden, Craig R. Allen Aug 2023

Functional Connectivity Varies Across Scales In A Fragmented Landscape, Kate I. T. Bird, Daniel R. Uden, Craig R. Allen

School of Natural Resources: Faculty Publications

Species of different sizes interact with the landscape differently because ecological structure varies with scale, as do species movement capabilities and habitat requirements. As such, landscape connectivity is dependent upon the scale at which an animal interacts with its environment. Analyses of landscape connectivity must incorporate ecologically relevant scales to address scale-specific differences. Many evaluations of landscape connectivity utilize incrementally increasing buffer distances or other arbitrary spatial delineations as scales of analysis. Instead, we used a mammalian body mass discontinuity analysis to objectively identify scales in the Central Platte River Valley (CPRV) of Nebraska, U.S.A. We implemented a graph-theoretic network …


Machine Learning Techniques To Predict The Air Quality Using Meteorological Data In Two Urban Areas In Sri Lanka, Lakindu Mampitiya, Namal Rathnayake, Lee P. Leon, Vishwanadham Mandala, Hazi Md. Azamathulla, Sherly Shelton, Yukinobu Hoshino, Upaka Rathnayake Aug 2023

Machine Learning Techniques To Predict The Air Quality Using Meteorological Data In Two Urban Areas In Sri Lanka, Lakindu Mampitiya, Namal Rathnayake, Lee P. Leon, Vishwanadham Mandala, Hazi Md. Azamathulla, Sherly Shelton, Yukinobu Hoshino, Upaka Rathnayake

Department of Earth and Atmospheric Sciences: Faculty Publications

The effect of bad air quality on human health is a well-known risk. Annual health costs have significantly been increased in many countries due to adverse air quality. Therefore, forecasting air quality-measuring parameters in highly impacted areas is essential to enhance the quality of life. Though this forecasting is usual in many countries, Sri Lanka is far behind the state-of-the-art. The country has increasingly reported adverse air quality levels with ongoing industrialization in urban areas. Therefore, this research study, for the first time, mainly focuses on forecasting the PM10 values of the air quality for the two urbanized areas …


Search For Higgs Boson Decay To A Charm Quark-Antiquark Pair In Proton-Proton Collisions At √S =13 Tev, A. Tumasyan Aug 2023

Search For Higgs Boson Decay To A Charm Quark-Antiquark Pair In Proton-Proton Collisions At √S =13 Tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H → c[], produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at √s = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb−1. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z → c[] in VZ events, leading to its first observation at a hadron collider with a significance …


Understanding The Factors Affecting Nebraskan Farmers’ And Landowners' Decision To Adopt Precision Agricultural Technologies And Programs, Corrin C. Winter Aug 2023

Understanding The Factors Affecting Nebraskan Farmers’ And Landowners' Decision To Adopt Precision Agricultural Technologies And Programs, Corrin C. Winter

School of Natural Resources: Dissertations, Theses, and Student Research

Advisors: Andrew Little, Christopher Chizinski

To gain insights into the challenges faced by Nebraska farmers and landowners when adopting precision agriculture technologies, I analyzed data collected from a 2022 survey involving 7,503 participants, consisting of producers and farmland owners from across the state of Nebraska. The primary objective was to provide valuable insights for agencies seeking to improve their precision agriculture and conservation outreach efforts for the benefit of conservation and Nebraskan farmers and landowners. This study aimed to understand key factors influencing adoption behaviors by evaluating the constraints to precision agriculture adoption, assessing the impact of producer and landowner …


Communication In The Science-Policy Interface: Evidence From A Boundary Organization In Nebraska, Usa, Sechindra Vallury, Brian C. Chaffin, Samantha L. Hamlin, Craig R. Allen Aug 2023

Communication In The Science-Policy Interface: Evidence From A Boundary Organization In Nebraska, Usa, Sechindra Vallury, Brian C. Chaffin, Samantha L. Hamlin, Craig R. Allen

School of Natural Resources: Faculty Publications

Boundary organizations have a crucial function in environmental governance by facilitating the processes through which scientists and decision-makers generate, exchange, evaluate, and utilize knowledge to identify societal problems, propose potential solutions, and make decisions on appropriate courses of action. This support for evidence-informed decision making is essential in addressing environmental challenges effectively. Despite the growing popularity of boundary organizations, there remains a significant challenge in designing information dissemination platforms to bridge the communication divide between scientific experts and non-experts. To address this gap, we used natural language processing tools to analyze the communication strategies of a specific boundary organization — …