Digital Commons Network^™

The Virago Paradigm Of Female Sanctity: Constructing The Masculine Woman In Medieval Christianity, Angela Bolen

Department of History: Dissertations, Theses, and Student Research

The Latin word virago, in its simplest definition, means “a man-like, warrior woman.” For Christian men and women in the Patristic era and the central Middle Ages, the virago represented a woman who denied all biological characteristics of her womanhood, fiercely protected her virginity, and fully embodied the virtues of Christian masculinity. The virago paradigm of female sanctity, a creation of male writers, reconciled a pervasive fear of the female sex with an obvious admiration for holy women. Additionally, the virago model maintained the supremacy of masculine virtues, upheld a patriarchal hierarchy, and created a metaphorical space that validated …

Spatiotemporal Trends In Bacterial Diversity Across Three Watersheds Within The Platte River Basin, Nebraska, Esther Perisho

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

River bacteria are understudied despite being critical components of river ecosystems. There are even fewer studies considering bacteria communities at large spatiotemporal scales, which may provide insight into drivers of community assembly. We investigated differences in bacterial diversity across environmental gradients within three sub-basins nested in the Platte River Basin, Nebraska. Surface water samples were collected weekly at 36 sites from May to September by the Nebraska Department of Environment and Energy (NDEE) in 2019. Bacterial communities were sequenced using the Illumina MiSeq platform. Sub-basins had similar counts of unique amplicon sequence variants (ASVs) but different community structures. These structural …

Characterization Of Western Corn Rootworm (Coleoptera: Chrysomelidae) Susceptibility To Foliar Insecticides In Northeast Nebraska, Timothy B. Dang

Department of Entomology: Dissertations, Theses, and Student Research

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of maize in the United States. A variety of tactics are used to manage this pest such as crop rotation, insecticides, and transgenic maize expressing insecticidal proteins from Bacillus thuringiensis (Bt). WCR populations are highly adaptive and have evolved resistance to these management tactics. Management options are limited as few new tactics are available. Research is needed to evaluate the value of existing tactics used within an integrated framework to manage densities/injury and mitigate resistance.

This study evaluated the field performance of formulated foliar insecticides …

Right Side Up: Payment For Ecosystem Services On Privately Owned Grasslands In Nebraska, Kyle Martens

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

Grasslands are an important ecological and economic resource in the United States. As part of a natural system, these landscapes can provide income for ranching operations and employment in rural communities; habitat for grassland plants, animals, and migratory species; and offer other services not always readily observed such as improved soil health, clean water, and carbon sequestration. Despite the overarching benefits, the conversion of grasslands to other uses remains widespread throughout much of the remaining Great Plains ecosystem.

Shifting from livestock ranching to another land use often reflects a tipping point. This occurs when the alternative land use is perceived …

African Swine Fever Virus Cd2v Protein Induces Β-Interferon Expression And Apoptosis In Swine Peripheral Blood Mononuclear Cells, Sabal Chaulangain, Gustavo A. Delhon, Sushil Khatiwada, Daniel L. Rock

School of Veterinary and Biomedical Sciences: Faculty Publications

African swine fever (ASF) is a hemorrhagic disease of swine characterized by massive lymphocyte depletion in lymphoid tissues due to the apoptosis of B and T cells, a process likely triggered by factors released or secreted by infected macrophages. ASFV CD2v (EP402R) has been implicated in viral virulence and immunomodulation in vitro; however, its actual function(s) remains unknown. We found that CD2v expression in swine PK15 cells induces NF-κB-dependent IFN-β and ISGs transcription and an antiviral state. Similar results were observed for CD2v protein treated swine PBMCs and macrophages, the major ASFV target cell. Notably, treatment of swine PBMCs and …

Biomaterials With Structural Hierarchy And Controlled 3d Nanotopography Guide Endogenous Bone Regeneration, Shixuan Chen, Hongjun Wang, Valerio Luca Mainardi, Giuseppe Talò, Alec Mccarthy, Johnson V. John, Matthew J. Teusink, Liu Hong, Jingwei Xie

Department of Chemistry: Faculty Publications

Biomaterials without exogenous cells or therapeutic agents often fail to achieve rapid endogenous bone regeneration with high quality. Here, we reported a class of three-dimensional (3D) nanofiber scaffolds with hierarchical structure and controlled alignment for effective endogenous cranial bone regeneration. 3D scaffolds consisting of radially aligned nanofibers guided and promoted the migration of bone marrow stem cells from the surrounding region to the center in vitro. These scaffolds showed the highest new bone volume, surface coverage, and mineral density among the tested groups in vivo. The regenerated bone exhibited a radially aligned fashion, closely recapitulating the scaffold’s architecture. The organic …

Metabolic Modeling And Omics-Integrative Analysis Of Single And Multi-Organism Systems: Discovery And Redesign, Mohammad Mazharul Islam

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Computations and modeling have emerged as indispensable tools that drive the process of understanding, discovery, and redesign of biological systems. With the accelerating pace of genome sequencing and annotation information generation, the development of computational pipelines for the rapid reconstruction of high-quality genome-scale metabolic networks has received significant attention. These models provide a rich tapestry for computational tools to quantitatively assess the metabolic phenotypes for various systems-level studies and to develop engineering interventions at the DNA, RNA, or enzymatic level by careful tuning in the biophysical modeling frameworks. in silico genome-scale metabolic modeling algorithms based on the concept of optimization, …

Management Of Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri S. Watson) In Dicamba/Glyphosate-Resistant Soybean, Shawn Thomas Mcdonald

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

While not a historically problematic weed in Nebraska, Palmer amaranth has become increasingly problematic in many agronomic cropping systems. Throughout the state, several cohorts of Palmer amaranth have been found resistant to several different sites of action. Of major concern is a population found resistant to glyphosate the most common post-emergence herbicide in Nebraska. As chemical control methods are the most common forms of weed control throughout the state methods alternatives or enhancements are highly desired. Two field experiments were conducted in 2018 and 2019 at a grower’s field near Carleton, Nebraska with the objectives to evaluate the effects of …

U.S. Geological Survey Science For The Wyoming Landscape Conservation Initiative—2018 Annual Report, Patrick J. Anderson, Cameron L. Aldridge, Jason S. Alexander, Timothy J.` Assal, Steven Aulenbach, Zachary H. Bowen, Anna D. Chalfoun, Geneva W. Chong, Holly Copeland, David R. Edmunds, Steve Germaine, Tabitha Graves, Julie A. Heinrichs, Collin G. Homer, Christopher G. Huber, Aaron N. Johnston, Matthew J. Kauffman, Daniel J. Manier, Ryan R. Mcshane, Cheryl A. Eddy-Miller, Kirk A. Miller, Adrian P. Monroe, Michael S. O'Donnell, Anna Ortega, Annika W. Walters, Daniel J. Wieferich, Teal B. Wyckoff, Linda Zeigenfuss

United States Geological Survey: Water Reports and Publications

The Wyoming Landscape Conservation Initiative (WLCI) was established in 2007 as a collaborative interagency partnership to develop and implement science-based conservation actions. During the past 11 years, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implement a long-term (more than 10 years) science-based program that assesses and enhances the quality and quantity of wildlife habitats in the southwest Wyoming region while facilitating responsible development. The USGS WLCI Science Team completes scientific research and develops tools that inform and support WLCI partner planning, decision making, and on-the-ground management actions.

In …

Bovine Mammary Alveolar Mac-T Cells Afford A Tool For Studies Of Bovine Milk Exosomes In Drug Delivery, Mojisola Ogunnaike

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Bovine milk exosomes (BMEs) have attracted attention as vehicles for delivering RNA therapeutics. BMEs originate in mammary alveolar cells. Here, we determined whether bovine mammary alveolar MAC-T cells are a promising tool to assess RNA delivery by BMEs. MAC-T cells exosomes (MAC-T BMEs) and BMEs were harvested by differential ultracentrifugation. Exosome size, morphology, microRNA content and marker proteins were assessed using nanoparticle tracking analysis, transmission electron microscopy, real-time PCR and immunoblot analysis, respectively. MAC-T cells were genetically engineered to secrete MAC-T BMEs endogenously labeled with a near-infrared fluorescent protein and tissue distribution was compared to fluorophore-labeled BMEs following intravenous injection …

Dynamical Variations Of The Global Covid-19 Pandemic Based On A Seicr Disease Model: A New Approach Of Yi Hua Jie Mu, Xia Wang, Gang Yin, Zengyun Hu, Daihai He, Qianqian Cui, Xiaomei Feng, Zhidong Teng, Qi Hu, Jiansen Li, Qiming Zhou

Department of Earth and Atmospheric Sciences: Faculty Publications

The ongoing coronavirus disease 2019 (COVID-19) pandemic has caused more than 150 million cases of infection to date and poses a serious threat to global public health. In this study, global COVID-19 data were used to examine the dynamical variations from the perspectives of immunity and contact of 84 countries across the five climate regions: tropical, arid, temperate, and cold. A new approach named Yi Hua Jie Mu is proposed to obtain the transmission rates based on the COVID-19 data between the countries with the same climate region over the Northern Hemisphere and Southern Hemisphere. Our results suggest that the …

Alcohol Use And History Of Traumatic Brain Injury In College Students: An Analysis Of Neuropsychological And Behavioral Factors, Jessie Tibbs

Department of Psychology: Dissertations, Theses, and Student Research

Approximately 69,000,000 individuals sustain TBIs each year worldwide. Alcohol use is a known risk factor for TBI. Nearly 50% of individuals with TBI endorse binge drinking, alcohol-related negative consequences, or meet criteria for AUDs. One of the most pressing issues within the alcohol-TBI literature is predicting post-TBI alcohol-related problems, as this results in poorer recovery, rehabilitation, and functioning. Evidence for TBIs causing post-injury alcohol use in those without pre-injury problematic alcohol use is mixed; not all TBI survivors experience alcohol-related problems post-injury. Evidence is mounting that one of the most robust predictors of post-injury alcohol problems is childhood or adolescent …

An Assessment Of The Factors Influencing The Prediction Accuracy Of Genomic Prediction Models Across Multiple Environments, Sarah Widener, George Graef, Alexander E. Lipka, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

The effects of climate change create formidable challenges for breeders striving to produce sufficient food quantities in rapidly changing environments. It is therefore critical to investigate the ability of multi-environment genomic prediction (GP) models to predict genomic estimated breeding values (GEBVs) in extreme environments. Exploration of the impact of training set composition on the accuracy of such GEBVs is also essential. Accordingly, we examined the influence of the number of training environments and the use of environmental covariates (ECs) in GS models on four subsets of n = 500 lines of the soybean nested association mapping (SoyNAM) panel grown in …

Near-Optimal Learning Of Tree-Structured Distributions By Chow-Liu, Arnab Bhattacharyya, Sutanu Gayen, Eric Price, N. V. Vinodchandran

Department of Mathematics: Faculty Publications

We provide finite sample guarantees for the classical Chow-Liu algorithm (IEEE Trans. Inform. Theory, 1968) to learn a tree-structured graphical model of a distribution. For a distribution P on Σⁿ and a tree T on n nodes, we say T is an ε-approximate tree for P if there is a T-structured distribution Q such that D(P || Q) is at most ε more than the best possible tree-structured distribution for P. We show that if P itself is tree-structured, then the Chow-Liu algorithm with the plug-in estimator for mutual information with eO (|Σ| …

Ruminant Milk-Derived Extracellular Vesicles: A Nutritional And Therapeutic Opportunity?, Siew Ling Ong, Cherie Blenkiron, Stephen Haines, Alejandra Acevedo-Fani, Juliana A.S. Leite, Janos Zempleni, Rachel C. Anderson, Mark J. Mccann

Department of Nutrition and Health Sciences: Faculty Publications

Milk has been shown to contain a specific fraction of extracellular particles that are reported to resist digestion and are purposefully packaged with lipids, proteins, and nucleic acids to exert specific biological effects. These findings suggest that these particles may have a role in the quality of infant nutrition, particularly in the early phase of life when many of the foundations of an infant’s potential for health and overall wellness are established. However, much of the current research focuses on human or cow milk only, and there is a knowledge gap in how milk from other species, which may be …

Semi Real-Time Detection Of Subsurface Consolidation Defects During Concrete Curing Stage, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Subsurface consolidation defect is a common issue in concrete pavement construction, and the hidden defects often require costly repairs after project delivery. Therefore, being able to identify this type of defect during construction will enable contractor to conduct quick repairs to avoid costly post-construction rework. In this paper a semi real-time detection approach using infrared thermography is introduced. The developed approach utilizes the hydration heat during curing time to identify the subsurface voids based on the regional temperature contrast. Experimental studies were conducted using artificial void-defect in different sizes and depths. The thermographic analysis is employed to locate the void-defects …

A Smartphone App For Individual Xylazine/Ketamine Calculation Decreased Anesthesia-Related Mortality In Mice, Carlos Poblete Jara, Rodrigo S. Carraro, Ariane Zanesco, Beatriz Andrade, Karina Moreira, Guilherme Nogueira, Bruno L. Souza, Thais Paulino Prado, Valeria Povoa, William Velander, Licio A. Velloso, Eliana P. Araujo

Department of Chemical and Biomolecular Engineering: Faculty Publications

Currently, experimental animals are widely used in biological and medical research. However, the scientific community has raised several bioethical concerns, such as the number of animals required to achieve reproducible and statistically relevant results. These concerns involve aspects related to pain, discomfort, and unwanted animal loss. Retrospectively, we compare two different approaches for anesthesia dosage: a mobile app for dose calculation and a standard dose calculation. A total of 939 C57BL/6J and Swiss mice were analyzed. We collected data on intraoperative and anesthesia-related mortality as described in electronic or physical handwritten records. Our results showed that the mobile app approach …

Generalist Bird Exhibits Site-Dependent Resource Selection, Samantha M. Cady, Craig A. Davis, Samuel D. Fuhlendorf, Rheinhardt Scholtz, Daniel R. Uden, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

Quantifying resource selection (an organism's disproportionate use of available resources) is essential to infer habitat requirements of a species, develop management recommendations, predict species responses to changing conditions, and improve our understanding of the processes that underlie ecological patterns. Because study sites, even within the same region, can differ in both the amount and the arrangement of cover types, our objective was to determine whether proximal sites can yield markedly different resource selection results for a generalist bird, northern bobwhite (Colinus virginianus). We used 5 years of telemetry locations and newly developed land cover data at two, geographically distinct but …

Methods , Systems , And Devices Relating To Surgical End Effectors, Shane M. Farritor, Thomas Frederick, Joe Bartels

Department of Mechanical and Materials Engineering: Faculty Publications

The embodiments disclosed herein relate to various medical device components , including components that can be incorporated into robotic and / or in vivo medical devices, and more specifically including end effectors that can be incorporated into such devices. Certain end effector embodiments include various vessel cautery devices that have rotational movement as well as cautery and cutting functions while maintaining a relatively compact structure. Other end effector embodiments include various end effector devices that have more than one end effector.

Oxygen Reactive Polymers For Treatment Of Traumatic Brain Injury, Parick S. Stayton, Menko P. Ypma, Peter A. Chiarelli, Joshua Sang Hun Park, Richard G. Ellenbogen, Julia Mengyun Xu, Pierre D. Mourad, Donghoon Lee, Anthony Convertime, Forrest M. Kievit

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Methods and compositions for treating traumatic brain injury . The methods and compositions utilize a multi - functional oxygen reactive polymer ( ORP ) that includes repeating units that include a reactive oxygen species ( ROS ) scavenging group and a polyalkylene oxide group . For theranostic applications , the oxygen reactive polymer fur ther includes a diagnostic group .

Developing Pandemic Comics For Youth Audiences, Judy Diamond, Amy Spiegel, Patricia Wonch Hill, Elizabeth Vanwormer, Judi M. Gaiashkibos, Bob Hall, Aaron Sutherlen, Julia Mcquillan

University of Nebraska State Museum: Staff and Affiliates, Publications

In spring 2020 our team received funding from the Rapid Response Research program of the National Science Foundation to develop comics that would help youth understand the COVID-19 pandemic. Our project built on a decade of expertise creating comics about the biology of viruses. In collaboration with virologists and artists, we developed three comic stories about COVID-19 during the pandemic and posted them on-line during the last half of 2020. The fictional narratives address fundamental issues in biology, virology, and network science, in order to help readers understand the complexities of living through a viral pandemic. The stories focus on …

Data From A Public–Industry Partnership For Enhancing Corn Nitrogen Research, C J. Ransom, J D. Clark, G M. Bean, C J. Bandura, M Shafer, N R. Kitchen, J J. Camberato, P R. Carter, R B. Ferguson, F G. Fernandez, D W. Franzen, C.A.M. Laboski, D B. Myers, E D. Nafziger, J E. Sawyer, J F. Shanahan

Department of Agronomy and Horticulture: Faculty Publications

Improving corn (Zea mays L.) N management is pertinent to economic and environmental objectives. However, there are limited comprehensive data sources to develop and test N fertilizer decision aid tools across a wide geographic range of soil and weather scenarios. Therefore, a public-industry partnership was formed to conduct standardized corn N rate response field studies throughout the U.S. Midwest. This research was conducted using a standardized protocol at 49 site-years across eight states over the 2014 to 2016 growing seasons with many soil, plant, and weather related measurements. This note provides the data (found in supplemental files), outlines the data, …

Compliance With Hand Sanitizer Quality During The Sars-Cov-2 Pandemic: Assessing The Impurities In An Ethanol Plant, Gabriel Cohen, Nathan Kreutzer, Katie M. Mowat, Ashraf Aly Hassan, Bruce I. Dvorak

Department of Civil and Environmental Engineering: Faculty Publications

Using alcohol-based disinfectants is an effective method for preventing the spread of COVID-19. However, non-traditional manufacturers of alcohol-based disinfectants, such as ethanol plants, need to undergo additional treatment to curb their impurities to limits set by the Food and Drug Association (FDA) to produce alcohol-based disinfectants. To transform them to disinfectant-grade alcohol, 17 process streams in a dry-mill ethanol plant were analyzed to determine the quality parameters for acetaldehyde, acetal, propanol, methanol, and water, including chemical oxygen demand, total suspended solids, and nutrients. Results suggest that the process stream generated by the distillation column requires further treatment because the acetaldehyde …

Thermal And Mechanical Analysis Of Bombyx Mori Silk Nanofibers, Justin Busnot

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

This thesis presents a study on the thermomechanical properties of Bombyx Mori silk nanofibers. These nanofibers were obtained from silkworm cocoons which were degummed to separate the fibroin and the sericin, the two proteins that make up silk. The fibroin was then centrifuged to remove insoluble particles and stored and 4°C before the electrospinning process. A parametric study of the electrospinning process was carried out in order to identify the factors allowing to obtain optimal mechanical properties. The current as well as the flow rate applied, the diameter of the syringe, the distance separating the syringe from collector or even …

Structural Insights Into The Functional Divergence Of Whib-Like Proteins In Mycobacterium Tuberculosis, Tao Wan, Magdalena Horova, Daisy Guiza Beltran, Shanren Li, Huey-Xian Wong, Li-Mei Zhang

Department of Agronomy and Horticulture: Faculty Publications

WhiB7 represents a distinct subclass of transcription factors in the WhiB-Like (Wbl) family, a unique group of iron-sulfur (4Fe-4S] cluster-containing proteins exclusive to the phylum of Actinobacteria. In Mycobacterium tuberculosis (Mtb), WhiB7 interacts with domain 4 of the primary sigma factor (σ_^A4) in the RNA polymerase holoenzyme and activates genes involved in multiple drug resistance and redox homeostasis. Here, we report crystal structures of the WhiB7:σ^A₄ complex alone and bound to its target promoter DNA at 1.55-Å and 2.6-Å resolution, respectively. These structures show how WhiB7 regulates gene expression by interacting with both …

Downscaling Of Far-Red Solar-Induced Chlorophyll Fluorescence Of Different Crops From Canopy To Leaf Level Using A Diurnal Data Set Acquired By The Airborne Imaging Spectrometer Hyplant, Bastian Siegmann, Maria Pilar Cendrero-Mateo, Sergio Cogliati, Alexander Damm, John Gamon, David Herrera, Christopehr Jedmowski, Laura Verena Junker-Frohn, Thorsten Kraska, Onno Muller, Patrick Rademske, Christiaan Van Der Tol, Juan Quiros-Vargas, Peiqi Yang, Uwe Rascher

School of Natural Resources: Faculty Publications

Remote sensing-based measurements of solar-induced chlorophyll fluorescence (SIF) are useful for assessing plant functioning at different spatial and temporal scales. SIF is the most direct measure of photosynthesis and is therefore considered important to advance capacity for the monitoring of gross primary production (GPP) while it has also been suggested that its yield facilitates the early detection of vegetation stress. However, due to the influence of different confounding effects, the apparent SIF signal measured at canopy level differs from the fluorescence emitted at leaf level, which makes its physiological interpretation challenging. One of these effects is the scattering of SIF …

The Future Of Wildlife Conservation Funding: What Options Do U.S. College Students Support?, Lincoln R. Larson, Markus Nils Peterson, Richard Von Furstenberg, Victoria R. Vayer, Kangjae Jerry Lee, Daniel Y. Choi, Kathryn Stevenson, Adam A. Ahlers, Christine Anhalt-Depies, Taniya Bethke, Jeremy T. Bruskotter, Christopher J. Chizinski, Brian Clark, Ashley A. Dayer, Kelly Heber Dunning, Benjamin Ghasemi, Larry Gigliotti, Alan Graefe, Kris Irwin, Samuel J. Keith, Matt Kelly, Gerard Kyle, Elizabeth Metcalf, Wayde Morse, Mark D. Needham, Neelam C. Poudyal, Michael Quartuch, Shari Rodriguez, Chelsie Romulo, Ryan L. Sharp, William Siemer, Matthew T. Springer, Brett Stayton, Richard Stedman, Taylor Stein, Timothy R. Van Deelen, Jason Whiting, Richelle L. Winkler, Kyle Maurice Woosnam

School of Natural Resources: Faculty Publications

Insufficient funding is a major impediment to conservation efforts around the world. In the United States, a decline in hunting participation threatens sustainability of the “user-pay, public benefit” model that has supported wildlife conservation for nearly 100 years, forcing wildlife management agencies to contemplate alternative funding strategies. We investigated support for potential funding options among diverse college students, a rapidly expanding and politically active voting bloc with a potentially powerful influence on the future of conservation. From 2018 to 2020, we surveyed 17,203 undergraduate students at public universities across 22 states. Students preferred innovative approaches to conservation funding, with 72% …

Cerebrum, Liver, And Muscle Regulatory Networks Uncover Maternal Nutrition Effects In Developmental Programming Of Beef Cattle During Early Pregnancy, Wellison J.S. Diniz, Matthew S. Crouse, Robert A. Cushman, Kyle J. Mclean, Joel S. Caton, Carl R. Dahlen, Lawrence P. Reynolds, Alison K. Ward

Roman L. Hruska U.S. Meat Animal Research Center: Reports

The molecular basis underlying fetal programming in response to maternal nutrition remains unclear. Herein, we investigated the regulatory relationships between genes in fetal cerebrum, liver, and muscle tissues to shed light on the putative mechanisms that underlie the effects of early maternal nutrient restriction on bovine developmental programming. To this end, cerebrum, liver, and muscle gene expression were measured with RNA-Seq in 14 fetuses collected on day 50 of gestation from dams fed a diet initiated at breeding to either achieve 60% (RES, n= 7) or 100% (CON, n= 7) of energy requirements. To build a tissue-to-tissue gene network, we …

Nitrogen Fertilization And Native C4 Grass Species Alter Abundance, Activity, And Diversity Of Soil Diazotrophic Communities, Jialin Hu, Jonathan D. Richwine, Patrick D. Keyser, Lidong Li, Fei Yao, Sindhu Jagadamma, Jennifer M. Debruyn

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Native C₄ grasses have become the preferred species for native perennial pastures and bioenergy production due to their high productivity under low soil nitrogen (N) status. One reason for their low N requirement is that C4 grasses may benefit from soil diazotrophs and promote biological N fixation. Our objective was to evaluate the impact of N fertilization rates (0, 67, and 202 kg N ha⁻¹ ) and grass species (switchgrass [Panicum virgatum] and big bluestem [Andropogon gerardii]) on the abundance, activity, diversity, and community composition of soil diazotrophs over three agricultural seasons (grass green-up, initial harvest, and second …

Call Repertoire And Inferred Ecotype Presence Of Killer Whales (Orcinus Orca) Recorded In The Southeastern Chukchi Sea, Brijonnay C. Madrigal, Jessica L. Crance, Catherine L. Berchok, Alison K. Stimpert

United States Department of Commerce: Staff Publications

Killer whales occur in the Arctic but few data exist regarding the ecotypes present. The calling behavior differs among ecotypes, which can be distinguished based on pulsed call type, call rate, and bandwidth. In this study, a passive acoustic recorder was deployed 75 km off Point Hope, Alaska, in the southeastern Chukchi Sea to identify which ecotypes were present. A total of 1323 killer whale pulsed calls were detected on 38 of 276 days during the summers (June–August) of 2013–2015. The majority of calls (n = 804, 61%) were recorded in 2013 with the most calls recorded in July …