Physical Sciences and Mathematics Commons^™

The Sensitivity Of Neotoma To Climate Change And Biodiversity Loss Over The Late Quaternary, Catalina P. Tomé, S. Kathleen Lyons, Seth D. Newsome, Felisa A. Smith

School of Biological Sciences: Faculty Publications

The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7,000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated …

Groundwater Level Assessment And Prediction In The Nebraska Sand Hills Using Lidar-Derived Lake Water Level, Nawaraj Shrestha, Aaron R. Mittelstet, Aaron R. Young, Troy E. Gilmore, David C. Gosselin, Yi Qi, Caner Zeyrek

School of Natural Resources: Faculty Publications

The spatial variability of groundwater levels is often inferred from sparsely located hydraulic head observations in wells. The spatial correlation structure derived from sparse observations is associated with uncertainties that spread to estimates at unsampled locations. In areas where surface water represents the nearby groundwater level, remote sensing techniques can estimate and increase the number of hydraulic head measurements. This research uses light detection and ranging (LIDAR) to estimate lake surface water level to characterize the groundwater level in the Nebraska Sand Hills (NSH), an area with few observation wells. The LIDAR derived lake groundwater level accuracy was within 40 …

Pyusercalc: A Revised Jupyter Notebook Calculator For Uranium-Series Disequilibria In Basalts, Lynne J. Elkins, Marc Spiegelman

Department of Earth and Atmospheric Sciences: Faculty Publications

Meaningful analysis of uranium-series isotopic disequilibria in basaltic lavas relies on the use of complex forward numerical models like dynamic melting (McKenzie, 1985, https://doi.org/10.1016/0012- 821x(85)90001-9) and equilibrium porous flow (Spiegelman & Elliott, 1993, https://doi.org/10.1016/0012- 821x(93)90155-3). Historically, such models have either been solved analytically for simplified scenarios, such as constant melting rate or constant solid/melt trace element partitioning throughout the melting process, or have relied on incremental or numerical calculators with limited power to solve problems and/or restricted availability. The most public numerical solution to reactive porous flow, UserCalc (Spiegelman, 2000, https:// doi.org/10.1029/1999gc000030) was maintained on a private institutional server for …

Mountain Lions Reduce Movement, Increase Efficiency During The Covid-19 Shutdown, John F. Benson, Heather N. Abernathy, Jeff A. Sikich, Seth P.D. Riley

School of Natural Resources: Faculty Publications

1. Wildlife strongly alter behaviour in response to human disturbance; however, fundamental questions remain regarding the influence of human infrastructure and activity on animal movement. The Covid-19 pandemic created a natural experiment providing an opportunity to evaluate wildlife movement during a period of greatly reduced human activity. Speculation in scientific reviews and the media suggested that wildlife might be increasing movement and colonizing urban landscapes during pandemic slowdowns. However, theory predicts that animals should move and use space as efficiently as possible, suggesting that movement might actually be reduced relative to decreased human activity.

2. We quantified space use, movement, …

Contemporary Challenges And Opportunities For The Management Of Bird Damage At Field Crop Establishment, Christophe Sausse, Alice Baux, Michel Bertrand, Elsa Bonnaud, Sonia Canavelli, Alexandra Destrez, Page E. Klug, Lourdes Olivera, Ethel Rodriguez, Guilllermo Tellechea, Sebastian Zuil

United States Department of Agriculture Wildlife Services: Staff Publications

Bird damage, from sowing to crop establishment, is an important issue for farmers in many parts of the world. However, reliable and cost-effective solutions remain elusive because management tools and research on the subject are limited. The spatial variability of damage across landscapes and the adaptative behaviour of birds create further challenges. Additionally, the issue must be tackled at the landscape scale and involve a variety of stakeholders with conflicting interests and objectives. We summarize some of the challenges and opportunities identified to face these difficulties and address four major research directions for operational solutions including 1) crop damage assessment, …

Cubesats Deliver New Insights Into Agricultural Water Use At Daily And 3 M Resolutions, Bruno Aragon, Matteo G. Ziliani, Rasmus Houborg, Trenton E. Franz, Matthew F. Mccabe

School of Natural Resources: Faculty Publications

Earth observation has traditionally required a compromise in data collection. That is, one could sense the Earth with high spatial resolution occasionally; or with lower spatial fidelity regularly. For many applications, both frequency and detail are required. Precision agriculture is one such example, with sub-10 m spatial, and daily or sub-daily retrieval representing a key goal. Towards this objective, we produced the first cloud-free 3 m daily evaporation product ever retrieved from space, leveraging recently launched nano-satellite constellations to showcase this emerging potential. Focusing on three agricultural fields located in Nebraska, USA, high-resolution crop water use estimates are delivered via …

Development Of A Flash Drought Intensity Index, Jason A. Otkin, Yafang Zhong, Eric D. Hunt, Jordan I. Christian, Jeffrey B. Basara, Hanh Nguyen, Matthew C. Wheeler, Trent W. Ford, Andrew Hoell, Mark Svoboda, Martha C. Anderson

Drought Mitigation Center: Faculty Publications

Flash droughts are characterized by a period of rapid intensification over sub-seasonal time scales that culminates in the rapid emergence of new or worsening drought impacts. This study presents a new flash drought intensity index (FDII) that accounts for both the unusually rapid rate of drought intensification and its resultant severity. The FDII framework advances our ability to characterize flash drought because it provides a more complete measure of flash drought intensity than existing classification methods that only consider the rate of intensification. The FDII is computed using two terms measuring the maximum rate of intensification (FD_INT) and average drought …

Study Of Quasimonoenergetic Electron Bunch Generation In Self-Modulated Laser Wakefield Acceleration Using Tw Or Sub-Tw Ultrashort Laser Pulses, E. P. Maldonado, R. E. Samad, A. Bonatto, R. P. Nunes, S. Banerjee, N. D. Vieira

Department of Physics and Astronomy: Faculty Publications

This work presents a study on laser wakefield electron acceleration in the self-modulated regime (SM-LWFA) using 50-fs laser pulses with energy on the mJ scale, at λ = 0.8 μm, impinging on a thin H₂ gas jet. Particle-in-cell simulations were performed using laser peak powers ranging from sub-terawatt to a few terawatts and plasma densities varying from the relativistic self-focusing threshold up to values close to the critical density. The differences in the obtained acceleration processes are discussed. Results show that bunched electron beams with full charge on the nC scale and kinetic energy in the MeV range …

Water Quality Threats, Perceptions Of Climate Change And Behavioral Responses Among Farmers In The Ethiopian Rift Valley, Tewodros R. Godebo, Marc A. Jeuland, Christopher J. Paul, Dagnachew L. Belachew, Peter G. Mccornick

Drought Mitigation Center: Faculty Publications

This work aims to assess water quality for irrigated agriculture, alongside perceptions and adaptations of farmers to climate change in the Main Ethiopian Rift (MER). Climate change is expected to cause a rise in temperature and variability in rainfall in the region, reducing surface water availability and raising dependence on groundwater. The study data come from surveys with 147 farmers living in the Ziway–Shala basin and water quality assessments of 162 samples from groundwater wells and surface water. Most groundwater samples were found to be unsuitable for long term agricultural use due to their high salinity and sodium adsorption ratio, …

Biotransformation Of Doxycycline By Brevundimonas Naejangsanensis And Sphingobacterium Mizutaii Strains, Ting He, Jianguo Bao, Yifei Leng, Daniel D. Snow, Shuqiong Kong, Tong Wang, Xu Li

Nebraska Water Center: Faculty Publications

The fate of doxycycline (DC), a second generation tetracycline antibiotic, in the environment has drawn increasing attention in recent years due to its wide usage. Little is known about the biodegradability of DC in the environment. The objective of this study was to characterize the biotransformation of DC by pure bacterial strains with respect to reaction kinetics under different environmental conditions and biotransformation products. Two bacterial strains, Brevundimonas naejangsanensis DD1 and Sphingobacterium mizutaii DD2, were isolated from chicken litter and characterized for their biotransformation capability of DC. Results show both strains rely on cometabolism to biotransform DC with tryptone as …

Drone-Based Magnetic Surveying In Eastern Nebraska, Sulaiman Albadi

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

A magnetic survey is one of the methods used by scientists to detect subsurface features. Magnetic surveys can be carried out by walking on the surface of the earth with a magnetic field reading device called a magnetometer. Alternatively, a magnetometer can be installed on a moving platform (aircraft, boat, drone, bicycle) to conduct a more efficient magnetic survey. The geophysics team at the University of Nebraska at Lincoln assembled a drone-based magnetic survey system in 2019 (Jacobson and Filina, 2019) that has proven effective in magnetic readings over the Northern Bounding Fault (NBF) in eastern Nebraska (Jacobson and Filina, …

An Integrated Food, Energy, And Water Nexus, Human Well-Being, And Resilience (Few-Wise) Framework: New Mexico, Kamini Yadav, Hatim M. Geli, Andres F. Cibils, Michael Hayes, Alexander Fernald, James Peach, Mohammed N. Sawalhah, Vincent C. Tidwell, Lindsay E. Johnson, Ashraf J. Zaied, Melakeneh G. Gedefaw

School of Natural Resources: Faculty Publications

Interconnected food, energy, and water (FEW) nexus systems face many challenges to support human well-being (HWB) and maintain resilience, especially in arid and semiarid regions like New Mexico (NM), United States (US). Insufficient FEW resources, unstable economic growth due to fluctuations in prices of crude oil and natural gas, inequitable education and employment, and climate change are some of these challenges. Enhancing the resilience of such coupled socio-environmental systems depends on the efficient use of resources, improved understanding of the interlinkages across FEW system components, and adopting adaptable alternative management strategies. The goal of this study was to develop a …

Fully Bayesian Analysis Of Relevance Vector Machine Classification With Probit Link Function For Imbalanced Data Problem, Wenyang Wang, Dongchu Sun, Peng Shao, Haibo Kuang, Cong Sui

Department of Statistics: Faculty Publications

The original RVM classification model uses the logistic link function to build the likelihood function making the model hard to be conducted since the posterior of the weight parameter has no closed-form solution. This article proposes the probit link function approach instead of the logistic one for the likelihood function in the RVM classification model, namely PRVM (RVM with the probit link function). We show that the posterior of the weight parameter in PRVM follows the Multivariate Normal distribution and achieves a closed-form solution. A latent variable is needed in our algorithms to simplify the Bayesian computation greatly, and its …

Optical Phonon Modes, Static And High-Frequency Dielectric Constants, And Effective Electron Mass Parameter In Cubic In2O3, Megan Stokey, Rafal Korlacki, Sean Knight, Alexander Ruder, Matthew J. Hilfiker, Zbigniew Galazka, Klaus Irmscher, Yuxuan Zhang, Hongping Zhao, Vanya Darakchieva, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A complete set of all optical phonon modes predicted by symmetry for bixbyite structure indium oxide is reported here from a combination of far-infrared and infrared spectroscopic ellipsometry, as well as first principles calculations. Dielectric function spectra measured on high quality, marginally electrically conductive melt grown single bulk crystals are obtained on a wavelength-by-wavelength (also known as point-by-point) basis and by numerical reduction of a subtle free charge carrier Drude model contribution. A four-parameter semi-quantum model is applied to determine all 16 pairs of infrared-active transverse and longitudinal optical phonon modes, including the high-frequency dielectric constant, ε_∞=4.05±0.05. The …

Corrigendum: Surface Termination And Schottky-Barrier Formation Of In4Se3(001) [Semiconductor Science And Technology (2020) 35 (065009) Doi: 10.1088/1361-6641/Ab7e45], Archit Dhingra, Pavlo V. Galiy, Lu Wang, Nataliia S. Vorobeva, Alexey Lipatov, Angel Torres, Taras M. Nenchuk, Simeon J. Gilbert, Alexander Sinitskii, Andrew J. Yost, Wai-Ning Mei, Keisuke Fukutani, Jia Shiang Chen, Peter Dowben

Peter Dowben Publications

Through the description of various surface terminations, the chain direction of In4Se3 in this paper [1] is implied to be in the plane of its surface. Even though the common convention for photoemission spectroscopy is to place z-axis along the surface normal, the axis perpendicular to the growth direction for this indium selenide is the crystallographic a-axis (and not the c-axis) [2–4]. Therefore, in our work the surface of In4Se3 should have been labeled (100), and not (001), to prevent any confusion that may have resulted from a less than conventional index notation. Data availability statement The data that support …

Colossal Intrinsic Exchange Bias From Interfacial Reconstruction In Epitaxial Cofe2 O4/Al2 O3 Thin Films, Detian Yang, Yu Yun, Arjun Subedi, Nicholas E. Rogers, David M. Cornelison, Peter Dowben, Xiaoshan Xu

Peter Dowben Publications

We have studied the epitaxial CoFe₂O₄ (111) films grown on Al₂O₃ (0001) substrates of different thickness at various temperature and discovered colossal intrinsic exchange bias up to 7 ± 2 kOe. X-ray and electron diffraction clearly indicate an interfacial layer about 2 nm of different crystal structure from the “bulk” part of the CoFe₂O₄ film. The thickness dependence of the exchange bias suggests a hidden antiferromagnetic composition in the interfacial layer that couples to the ferrimagnetic “bulk” part of the CoFe₂O₄ film as the origin of the exchange …

Chudnovsky's Conjecture And The Stable Harbourne-Huneke Containment, Sankhaneel Bisui, Eloísa Grifo, Huy Tài Hà, Thái Thành Nguyên

Department of Mathematics: Faculty Publications

We investigate containment statements between symbolic and ordinary powers and bounds on the Waldschmidt constant of defining ideals of points in projective spaces. We establish the stable Harbourne conjecture for the defining ideal of a general set of points. We also prove Chudnovsky’s Conjecture and the stable version of the Harbourne–Huneke containment conjectures for a general set of sufficiently many points.

Demailly's Conjecture And The Containment Problem, Sankhaneel Bisui, Eloisa Grifo, Huy Tài Hà, Thái Thành Nguyên

Department of Mathematics: Faculty Publications

We investigate Demailly’s Conjecture for a general set of sufficiently many points. Demailly’s Conjecture generalizes Chudnovsky’s Conjecture in providing a lower bound for the Waldschmidt constant of a set of points in projective space. We also study a containment between symbolic and ordinary powers conjectured by Harbourne and Huneke that in particular implies Demailly’s bound, and prove that a general version of that containment holds for generic determinantal ideals and defining ideals of star configurations.

Modeling Vadose Zone Hydrology: Lecture Notes, Derek M. Heeren, Dean Eisenhauer

Open Educational Resources for Engineering

Modeling Vadose Zone Hydrology is a graduate-level course offered biennially in the Department of Biological Systems Engineering. Topics included hydraulic properties of porous media, application of Darcy's Law in variably saturated media, hydrologic and transport processes in the vadose zone, and solution of steady and unsteady flow problems using numerical techniques. A graphical approach for characterizing vertical one-dimensional problems with energy head profiles was emphasized. Common one-dimensional flow and transport problems were solved analytically. The course was taught using a combination of lecture notes and PowerPoint presentations. The lecture notes from 2021, captured using the Microsoft Whiteboard app with a …

N-Fold Matrix Factorizations, Eric Hopkins

Department of Mathematics: Dissertations, Theses, and Student Research

The study of matrix factorizations began when they were introduced by Eisenbud; they have since been an important topic in commutative algebra. Results by Eisenbud, Buchweitz, and Yoshino relate matrix factorizations to maximal Cohen-Macaulay modules over hypersurface rings. There are many important properties of the category of matrix factorizations, as well as tensor product and hom constructions. More recently, Backelin, Herzog, Sanders, and Ulrich used a generalization of matrix factorizations -- so called N-fold matrix factorizations -- to construct Ulrich modules over arbitrary hypersurface rings. In this dissertation we build up the theory of N-fold matrix factorizations, proving analogues of …

Alfaxalone Successfully Immobilizes Small Indian Mongooses (Urva Auropunctata): A Field Report, Caroline C. Sauvé, Yves Rondenay, Are R. Berentsen, Mel J. Rivera-Rodriguez, Patrick A. Leighton

United States Department of Agriculture Wildlife Services: Staff Publications

We investigated intramuscular administration of alfaxalone (5.3–10.0 mg/kg) as an immobilizing agent in free-ranging small Indian mongooses (Urva auropunctata) on the island of St. Kitts, West Indies. From 5–11 January 2020, we successfully immobilized 10 of 11 mongooses. Alfaxalone provided rapid onset (median = 3 min) of immobilization. Mean duration of immobilization was 16.8 ± 3 min. Mean recovery time was 5.6 ± 1 min. There was no effect of dose administered on induction, anesthesia, or recovery times at the dose range used. We concluded that alfaxalone represents an effective alternative to dissociative agents for the immobilization of free-ranging mongooses. …

Comparing Management Programs To Reduce Red–Tailed Hawk Collisions With Aircraft, Brian Washburn, Craig K. Pullins, Travis L. Guerrant, Gregory J. Martinelli, Scott F. Beckerman

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Raptors (i.e., hawks and owls) are one of the most frequently struck guilds of birds within North America. Although raptors (most notably red-tailed hawks [Buteo jamaicensis]) are commonly managed at most airports and military bases, there is no scientific information available regarding comparisons of the efficacy of raptor management programs for reducing raptor-aircraft collisions. Therefore, we conducted a study to examine the efficacy of 2 raptor hazard management programs implemented at Chicago's O'Hare International Airport (ORD). The first raptor management program (Phase I) occurred during January 2010–June 2013 and …

Strategic Testing Approaches For Targeted Disease Monitoring Can Be Used To Inform Pandemic Decision-Making, James D. Nichols, Tiffany L. Bogich, Emily Howerton, Ottar N. Bjørnstad, Rebecca K. Borchering, Matthew Ferrari, Murali Haran, Christopher Jewell, Kim M. Pepin, William J.M. Probert, Juliet R.C. Pulliam, Michael C. Runge, Michael Tildesley, Cecile Viboud, Katriona Shea

United States Department of Agriculture Wildlife Services: Staff Publications

More than 1.6 million Servere Acute Respiratory Syndrome Cronovirus 2(SARS-COV-2)tests were administered daily in the United States at the peak of the epidemic, with a significant focus on individual treatment. Here, we show that objective-driven, strategic sampling designs and analyses can maximize information gain at the population level, which is necessary to increase situational awareness and predict, prepare for, and respond to a pandemic, while also continuing to inform individual treatment. By focusing on specific objectives such as individual treatment or disease prediction and control (e.g., via the collection of population- level statistics to inform lockdown measures or vaccine rollout) …

An Evaluation Of Body-Grip Trap Trigger Configurations For Reducing River Otter Take Incidental To Beaver Trapping, Alec J. Sundelius, Nicholas Forman, Nathan M. Roberts, Shawn T. Rossler, David B. Ruid, Robert C. Willging

United States Department of Agriculture Wildlife Services: Staff Publications

River otter (Lontra canadensis) populations in North America have been the focus of significant restoration efforts. Wildlife management agencies, concerned about the unintentional take of river otters incidental to beaver (Castor canadensis) trapping, may recommend techniques to avoid capturing river otters. River otter avoidance techniques that are ineffective or diminish trap performance for beavers are undesirable. We conducted a field evaluation in 2015 and 2016 in Wisconsin to assess how two trigger configurations (offset and center) on body-grip traps would affect the incidental capture rate of river otters during beaver trapping. We also evaluated effects of …

Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Fracture is one of the main mechanisms of structural failure. Corroded surfaces with chemically-induced damage are, notably, potential sites for crack initiation and propagation in metals, which can lead to catastrophic failure of structures. Despite some progress in simulating fracture and damage using classical models, realistic prediction of complex damage progression and failure has been out of reach for many decades. Peridynamics (PD), a nonlocal theory introduced in 2000, opened up new avenues in modeling material degradation and failure. Existing numerical methods used to discretize PD equations, however, are quite expensive as the PD nonlocal interactions make them unaffordable for …

Spatiotemporal Analysis Of Extreme Precipitation In The Missouri River Basin From 1950 To 2019, Paul Flanagan, Rezaul Mahmood

School of Natural Resources: Faculty Publications

Extreme precipitation events are challenging to local and regional stakeholders across the United States. The Missouri River basin (MoRB), covering an area over 1.29 million km², is prone to extreme precipitation events. These events are exacerbated by the complex terrain in the west and the numerous weather and climate features that impact the region on a seasonal and annual basis (low-level jets, mesoscale convective systems, extreme cold air intrusions, etc.). Without an in-depth analysis of extreme precipitation in the MoRB, the evolving nature of extreme precipitation is not known. This situation warrants an analysis of extreme precipitation, especially …

Brown Treesnake Mortality After Aerial Application Of Toxic Baits, Scott M. Goetz, Eric T. Hileman, Melia G. Nafus, Amy A. Yackel Adams, Amanda R. Bryant, Robert N. Reed, Shane R. Siers

United States Department of Agriculture Wildlife Services: Staff Publications

Quantitative evaluation of control tools for managing invasive species is necessary to assess overall effectiveness and individual variation in treatment susceptibility. Invasive brown treesnakes (Boiga irregularis) on Guam have caused severe ecological and economic effects, pose a risk of accidental introduction to other islands, and are the greatest impediment to the reestablishment of extirpated native fauna. An aerial delivery system for rodent‐based toxic baits can reduce brown treesnake abundance and heterogeneity among individuals may influence bait attraction or toxicant susceptibility. Previous baiting trials have either been simulated aerial treatments or relied on slightly different bait capsule compositions and the results …

Towards A Machine Learning Based Generalizable Framework For Detecting Covid-19 Misinformation On Social Media, Yuanzhi Chen

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

Since the beginning of the COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, online social media has become a conduit for the rapid propagation of misinformation. The misinformation is a type of fake news that is created inadvertently without the intention of causing harm. Yet COVID-19 misinformation has caused serious social disruptions including accidental death and destruction of public property. Timely prevention of the propagation of online misinformation requires the development of automated detection tools. Machine learning (ML) based models have been used to automate techniques for identifying fake news. These techniques involve converting text data …

Using An Integrative Machine Learning Approach To Study Microrna Regulation Networks In Pancreatic Cancer Progression, Roland Madadjim

Department of Computer Science and Engineering: Dissertations, Theses, and Student Research

With advances in genomic discovery tools, recent biomedical research has produced a massive amount of genomic data on post-transcriptional regulations related to various transcript factors, microRNAs, lncRNAs, epigenetic modifications, and genetic variations. In this direction, the field of gene regulation network inference is created and aims to understand the interactome regulations between these molecules (e.g., gene-gene, miRNA-gene) that take place to build models able to capture behavioral changes in biological systems. A question of interest arises in integrating such molecules to build a network while treating each specie in its uniqueness. Given the dynamic changes of interactome in chaotic systems …

Real-Time Monitoring Of Fdm 3d Printer For Fault Detection Using Machine Learning: A Bibliometric Study, Vaibhav Kisan Kadam, Satish Kumar, Arunkumar Bongale

Library Philosophy and Practice (e-journal)

Additive Manufacturing has wide application range including healthcare, Fashion, Manufacturing, Prototypes, Tooling etc. AM techniques are subjected to various defects that may be printing defects or anomalies in machine. There is gap between current AM techniques and smart manufacturing since current AM lacks in build sensors necessary for process monitoring and fault detection. Both of these issues can be solved by incorporating real-time monitoring into AM. So the study is carried out to identify recent work done in AM to improve current system. For this bibliometric study Scopus database is used, study is kept limited to year 2010-2021 and English …