Digital Commons Network^™

Impacts Of Drought On Plant Water Relations And Nitrogen Nutrition In Dryland Perennial Grasses, Albina Khasanova, Jeremy J. James, Rebecca E. Drenovsky

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

Background and aims Extensive worldwide dryland degradation calls for identification of functional traits critical to dryland plant performance and restoration outcomes. Most trait examination has focused on drought tolerance, although most dryland systems are water and nutrient co-limited. We studied how drought impacts both plant water relations and nitrogen (N) nutrition.

Methods We grew a suite of grasses common to the Intermountain West under both well-watered and drought conditions in the greenhouse. These grasses represented three congener pairs (Agropyron, Elymus, Festuca) differing in their habitat of origin (“wetter” or “drier”). We measured growth, water relations, N resorption efficiency …

Feed Management Practices To Reduce Manure Phosphorus Excretion In Dairy Cattle, E. Kebreab, A. V. Hansen, B. Leytem

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

Phosphorus (P) is an essential mineral that needs to be supplied in sufficient quantities for maintenance and growth and milk production in dairy cattle. However, over 60% of the P consumed can be excreted in faeces with a potential to cause environmental pollution. Concern over higher levels of P in intensively managed livestock systems has led to legislation such as the Water Framework Directive in the European Union. In this manuscript, several methods of reducing P pollution are discussed. A major source of environmental P pollution has been overfeeding P mainly due to addition of ‘safety margin’ over the animal’s …

Competencies And Experiences Needed By Pre–Service Agricultural Educators To Teach Globalized Curricula: A Modified Delphi Study, Nathan Conner, T. Grady Roberts

Department of Agricultural Leadership, Education, and Communication: Faculty Publications

The 21st century graduate must be able to interact with people from all over the world and must also be knowledgeable about the world (Longview Foundation, 2008). In order to produce graduates that are globally competent, The National Council for the Accreditation of Teachers (NCATE, 1982) has mandated that multi–cultural education be incorporated as part of the teacher–preparation curricula. The purpose of this study was to identify competencies and experiences needed by agricultural pre–service teachers in order to teach globalized curricula. A modified Delphi method was used and the panel consisted of 13 (n = 13) experts in the field …

Hrtm 479: Perspectives On The Hospitality Industry (Capstone Course)—A Peer Review Of Teaching Project Benchmark Portfolio, Dipra Jha

UNL Faculty Course Portfolios

This benchmark portfolio investigates teaching and learning in HRTM 479: Perspectives on the Hospitality Industry, a senior capstone course for Hospitality, Restaurant and Tourism management majors, which integrates hospitality core and content courses into managerial and leadership practice within the hospitality, restaurant and tourism industry.

Wildlife Contact Rates At Artificial Feeding Sites In Texas, Tyler A. Campbell, David Long, Susan A. Shriner

United States Department of Agriculture Wildlife Services: Staff Publications

Given the popularity of feeding white-tailed deer (Odocoileus virginianus) in Texas and the increasing amount of corn that is distributed, more information is needed on the impacts of this activity on non-target wildlife. Our objectives were to report visitation, intra- and interspecific contact, and contact rates of wildlife at artificial feeding sites in Texas. Our study was conducted at three sites in Kleberg and Nueces counties, Texas. We trapped animals from February to April and August to September, 2009 and marked animals with passive integrated transponder (PIT) tags. At each site and season, we placed one feeder system containing a …

Genetic Mapping And Confirmation Of Quantitative Trait Loci For Seed Protein And Oil Contents And Seed Weight In Soybean, Safiullah M. Pathan, Tri Vuong, Kerry Clark, Jeong-Dong Lee, J. Grover Shannon, Craig A. Roberts, Mark R. Ellersieck, Joseph W. Burton, P. B. Cregan, David L. Hyten, Henry T. Nguyen, David A. Sleper

Department of Agronomy and Horticulture: Faculty Publications

Demand for soybean [Glycine max (L.) Merr.] meal has increased worldwide and soybean importers often offer premiums for soybean containing higher contents of protein and oil. Objectives were to detect quantitative trait loci (QTL) associated with soybean seed protein, oil, and seed weight in a soybean mapping population and confirm detected QTL across genetic backgrounds and environments. Two populations of 216 and 156 recombinant inbred lines were developed from Magellan × PI 438489B and Magellan × PI 567516C crosses, respectively, and grown in two Missouri environments in 2008. More than 900 simple sequence repeat (SSR) and single nucleotide polymorphism …

The Evolution Of Animal Identification In Beef Cattle, Kristy E. Boehler

Nebraska Law Review

The United States’ beef cattle industry’s recent past has been plagued by a lack of a national animal identification system. The lack of a national animal identification system has made it difficult, if not impossible, to track a diseased animal back to its farm of origin or determine what other cattle have been in contact with the diseased animal. In fact, during the investigation of the December 2003 Bovine Spongiform Encephalopathy (Mad Cow Disease) outbreak, the lack of a national animal identification system meant that the United States was only able to locate twenty-eight of the eighty cows that entered …

Do Non-Response Follow-Ups Improve Or Reduce Data Quality?: A Review Of The Existing Literature, Kristen Olson

Department of Sociology: Faculty Publications

The paper systematically reviews existing literature on the relationship between the level of effort to recruit a sampled person and the measurement quality of survey data. Hypotheses proposed for this relationship are reviewed. Empirical findings for the relationship between level of effort as measured by paradata (the number of follow-up attempts, refusal conversion and time in the field) and question-specific item non-response rates, aggregate measures of item non-response rates, response accuracy and various measurement errors on attitudinal questions are examined through a qualitative review.

Paradata For Nonresponse Adjustment, Kristen Olson

Department of Sociology: Faculty Publications

Survey researchers and practitioners use nonresponse adjustment weights to mitigate the effects of survey nonresponse on sample estimates. One challenge in creating these weights is finding useful auxiliary data that predict both the probability of participating in the survey and the survey variables of interest. This article reviews the use of paradata for nonresponse adjustment. Five different types of paradata are considered: neighborhood observations, observations of the sampled housing unit, observations of persons in the sampled housing unit, call records, and observations about the interviewer-householder interaction. Empirical evidence about the predictive value of these paradata for predicting both participation and …

Electropalatography As An Adjunct To Nonspeech Orofacial Myofunctional Disorder Assessments: A Feasibility Study, Alana Mantie-Kozlowski, Kevin M. Pitt

Department of Special Education and Communication Disorders: Faculty Publications

The purpose of this study was to determine if electropalatography (EPG) would be a useful adjunct and feasible option for those conducting clinical assessments of individuals with suspected nonspeech orofacial myofunctional disorders (NSOMD). Three females (two adults, one child) were referred by their orthodontist for assessment of suspected NSOMD. Three adults and one child without NSOMD were recruited for the purpose of evaluating methodological construct, and to provide comparisons for participants with NSOMD. Using EPG, lingual-palatal timing and contact patterns of 105 saliva swallows (45 with NSOMD, 60 without NSOMD) were analyzed by compartmentalizing the sensor display and tracking the …

Human Health And The Neolithic Revolution: An Overview Of Impacts Of The Agricultural Transition On Oral Health, Epidemiology, And The Human Body, Katherine J. Latham

Nebraska Anthropologist

The transition from a hunter-gatherer lifestyle to dependence on agricultural production is commonly considered one of the most important achievements of human history. This transition, often referred to as the Neolithic Revolution, ushered in a variety of changes in human dietary intake, food processing and procurement methods, settlement patterns, and physical activity. Skeletal analyses of human remains from early agricultural centers throughout the world indicate that this revolution significantly affected overall human health. This paper will address some of the drastic effects of this transition as evidenced by craniofacial changes related to masticatory function, declines in oral health, increased spread …

Comparison Of Two Perennial Grass Breeding Systems With Switchgrass, Kenneth P. Vogel

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

Two breeding systems, between- and withinfamily selection (BWFS) and multistep family selection (MFS), were compared using three switchgrass (Panicum virgatum L.) populations to determine which system was the most effective in improving biomass yield and in vitro dry matter digestibility (IVDMD). With BWFS, half-sib families are produced and evaluated on a family basis and then the best plants within the best families are selected for crossing to produce a new strain. With MFS, parent genotypes of the half-sib families being evaluated in the BWFS selection nursery are maintained and the genotypes whose progeny were the best in the BWFS …

Effects Of Drought, Temperature, Herbivory, And Genotype On Plant–Insect Interactions In Soybean (Glycine Max), Rose Grinnan, Thomas E. Carter Jr., Marc T. J. Johnson

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

Climate change is predicted to cause continued increases in global temperatures, greater variability in precipitation and in some cases, more frequent insect pest outbreaks. Here we seek to understand how abiotic and biotic stresses associated with climate change can affect plant-herbivore interactions in a model crop species (soybean, Glycine max (L.) Merr.) by answering three questions: (1) Do the combined effects of abiotic and biotic stresses associated with climate change cause synergistic negative effects on plant biomass? (2) Can abiotic stress affect resistance of plants to insect herbivores? (3) Does genetic variation in plant traits modify a plant’s response to …

On The Halophytic Nature Of Mangroves, Ken W. Krauss, Marilyn C. Ball

United States Geological Survey: Staff Publications

Scientists have discussed the halophytic nature of intertidal plants for decades, and have generally suggested that inherent differentiation of an obligate halophyte from a facultative halophyte relates strongly to whether the plant can survive in fresh water, and not much else. In this minireview, we provide additional insight to support the pervasive notion that mangroves as a group are truly facultative halophytes, and thus add discourse to the alternate view that mangroves have an obligate salinity requirement. Indeed, growth and physiological optima are realized at moderate salinity concentrations in mangroves, but we maintain the notion that current evidence suggests that …

Effects Of Historical Lead–Zinc Mining On Riffle-Dwelling Benthic Fish And Crayfish In The Big River Of Southeastern Missouri, Usa, A. L. Allert, R. J. Distefano, J. F. Fairchild, C. J. Schmitt, M. J. Mckee, J. A. Girondo, W. G. Brumbaugh, T. W. May

United States Geological Survey: Staff Publications

The Big River (BGR) drains much of the Old Lead Belt mining district (OLB) in southeastern Missouri, USA, which was historically among the largest producers of lead–zinc (Pb–Zn) ore in the world. We sampled benthic fish and crayfish in riffle habitats at eight sites in the BGR and conducted 56-day in situ exposures to the woodland crayfish (Orconectes hylas) and golden crayfish (Orconectes luteus) in cages at four sites affected to differing degrees by mining. Densities of fish and crayfish, physical habitat and water quality, and the survival and growth of caged crayfish were examined at …

Glutaredoxin-2 Is Required To Control Proton Leak Through Uncoupling Protein-3, Ryan J. Mailloux, Jian Ying Xuan, Brittany Beauchamp, Marjorie F. Lou, Mary-Ellen Harper

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutathionylation has emerged as a key modification required for controlling protein function in response to changes in cell redox status. Recently, we showed that the glutathionylation state of uncoupling protein-3 (UCP3) modulates the leak of protons back into the mitochondrial matrix, thus controlling reactive oxygen species production. However, whether or not UCP3 glutathionylation is mediated enzymatically has remained unknown because previous work relied on the use of pharmacological agents, such as diamide, to alter the UCP3 glutathionylation state. Here, we demonstrate that glutaredoxin-2 (Grx2), a matrix oxidoreductase, is required to glutathionylate and inhibit UCP3. Analysis of bioenergetics in skeletal muscle …

Effects Of Dynamic Stretching On Strength, Muscle Imbalance, And Muscle Activation, Pablo B. Costa, Trent J. Herda, Ashley A. Herda, Joel T. Cramer

Department of Nutrition and Health Sciences: Faculty Publications

Purpose: This study aimed to examine the acute effects of dynamic stretching on concentric leg extensor and flexor peak torque, eccentric leg flexor peak torque, and the conventional and functional hamstring–quadriceps (H:Q) ratios.

Methods: Twenty-one women (mean ± SD age = 20.6 ± 2.0 yr, body mass = 64.5 ± >.3 kg, height = 164.7 ± 6.5 cm) performed maximal voluntary isokinetic leg extension, flexion, and eccentric hamstring muscle actions at the angular velocities of 60°· s^-1 and 180° · s^-1 before and after a bout of dynamic hamstring and quadriceps stretching as well as a …

Vitamin B12 Deficiency In Relation To Functional Disabilities, Breanna S. Oberlin, Christy C. Tangney, Kristin A. R. Gustashaw, Heather E. Rasmussen

Department of Nutrition and Health Sciences: Faculty Publications

This study was designed to assess whether symptoms, functional measures, and reported disabilities were associated with vitamin B12 (B12) deficiency when defined in three ways. Participants, aged 60 or more years of age, in 1999–2002 National Health and Nutrition Examination Surveys (NHANES) were categorized in relation to three previously used definitions of B12 deficiency: (1) serum B12 < 148 pmol/L; (2) serum B12 < 200 pmol/L and serum homocysteine > 20 μmol/L; and (3) serum B12 < 258 pmol/L or serum methylmalonic acid > 0.21 μmol/L. Functional measures of peripheral neuropathy, balance, cognitive function, gait speed, along with self-reported disability (including activities of daily living) were examined with standardized instruments by trained NHANES interviewers and technicians. Individuals identified as B12 deficient …

Relationship Between Serum And Brain Carotenoids, 𝛼-Tocopherol, And Retinol Concentrations And Cognitive Performance In The Oldest Old From The Georgia Centenarian Study, Elizabeth J. Johnson, Rohini Vishwanathan, Mary Ann Johnson, Dorothy B. Hausman, Adam Davey, Tammy M. Scott, Robert C. Green, L. Stephen Miller, Marla Gearing, John Woodard, Peter T. Nelson, Hae-Yun Chung, Wolfgang Schalch, Jonas Wittwer, Leonard W. Poon

Department of Nutrition and Health Sciences: Faculty Publications

Oxidative stress is involved in age-related cognitive decline. The dietary antioxidants, carotenoids, tocopherols, and vitamin A may play a role in the prevention or delay in cognitive decline. In this study, sera were obtained from 78 octogenarians and 220 centenarians from the Georgia Centenarian Study. Brain tissues were obtained from 47 centenarian decedents. Samples were analyzed for carotenoids, 𝛼-tocopherol, and retinol using HPLC. Analyte concentrations were compared with cognitive tests designed to evaluate global cognition, dementia, depression and cognitive domains (memory, processing speed, attention, and executive functioning). Serum lutein, zeaxanthin, and 𝛽-carotene concentrations were most consistently related to better cognition …

Nutrition, Histone Epigenetic Marks, And Disease, Janos Zempleni, Dandan Liu, Jing Xue

Department of Nutrition and Health Sciences: Faculty Publications

The dietary intake of essential nutrients and bioactive food compounds is a process that occurs on a daily basis for the entire life span. Therefore, your diet has a great potential to cause changes in the epigenome. Known histone modifications include acetylation, methylation, biotinylation, poly(ADP-ribosylation), ubiquitination, and sumoylation. Some of these modifications depend directly on dietary nutrients. For other modifications, bioactive dietary compounds may alter the activities of enzymes that establish or remove histone marks, thereby altering the epigenome. This chapter provides an overview of diet-dependent epigenomic marks in histones and their links with human health.

Myeloid Cell-Specific Abca1 Deletion Does Not Worsen Insulin Resistance In Hf Dietinduced Or Genetically Obese Mouse Models, Xuewei Zhu, Soonkyu Chung, Xin Bi, Chia-Chi Chuang, Amanda L. Brown, Mingxia Liu, Jeongmin Seo, Helen Cuffe, Abraham K. Gebre, Elena Boudyguina, John S. Parks

Department of Nutrition and Health Sciences: Faculty Publications

Obesity-associated low-grade chronic inflammation plays an important role in the development of insulin resistance. The membrane lipid transporter ATP-binding cassette transporter A1 (ABCA1) promotes formation of nascent HDL particles. ABCA1 also dampens macrophage inflammation by reducing cellular membrane cholesterol and lipid raft content. We tested the hypothesis that myeloid-specific ABCA1 deletion may exacerbate insulin resistance by increasing the obesity-associated chronic low-grade inflammation. Myeloid cell-specific ABCA1 knockout (MSKO) and wild-type (WT) mice developed obesity, insulin resistance, mild hypercholesterolemia, and hepatic steatosis to a similar extent with a 45% high-fat (HF) diet feeding or after crossing into the ob/ob background. Resident peritoneal …

Echium Oil Reduces Plasma Triglycerides By Increasing Intravascular Lipolysis In Apob100-Only Low Density Lipoprotein (Ldl) Receptor Knockout Mice, Lolita M. Forrest, Christopher M. Lough, Soonkyu Chung, Elena Y. Boudyguina, Abraham K. Gebre, Thomas L. Smith, Perry L. Colvin, John S. Parks

Department of Nutrition and Health Sciences: Faculty Publications

Echium oil (EO), which is enriched in SDA (18:4 n-3), reduces plasma triglyceride (TG) concentrations in humans and mice. We compared mechanisms by which EO and fish oil (FO) reduce plasma TG concentrations in mildly hypertriglyceridemic male apoB100-only LDLrKO mice. Mice were fed one of three atherogenic diets containing 0.2% cholesterol and palm oil (PO; 20%), EO (10% EO + 10% PO), or FO (10% FO + 10% PO). Livers from PO- and EO-fed mice had similar TG and cholesteryl ester (CE) content, which was significantly higher than in FO-fed mice. Plasma TG secretion was reduced in FO vs. EO-fed …

Identification And Assessment Of Markers Of Biotin Status In Healthy Adults, Wei Kay Eng, David Giraud, Vicki L. Schlegel, Dong Wang, Bo Hyun Lee, Janos Zempleni

Department of Nutrition and Health Sciences: Faculty Publications

Human biotin requirements are unknown and the identification of reliable markers of biotin status is necessary to fill this knowledge gap. Here, we used an outpatient feeding protocol to create states of biotin deficiency, sufficiency and supplementation in sixteen healthy men and women. A total of twenty possible markers of biotin status were assessed, including the abundance of biotinylated carboxylases in lymphocytes, the expression of genes from biotin metabolism and the urinary excretion of biotin and organic acids. Only the abundance of biotinylated 3-methylcrotonyl-CoA carboxylase (holo-MCC) and propionyl-CoA carboxylase (holo-PCC) allowed for distinguishing biotin-deficient and biotin-sufficient individuals. The urinary excretion …

Meeting The Leadership Challenge Of Employee Well-Being Through Relationship Psycap And Health Psycap, Fred Luthans, Carolyn M. Youssef, David S. Sweetman, Peter D. Harms

Department of Management: Faculty Publications

Increasing recognition is being given to the role that employee overall well-being plays in desired outcomes of today’s organizations. To help organizational leaders searching for understanding and answers, we propose that the positive core construct of psychological capital (or simply PsyCap), consisting of the positive psychological resources of hope, efficacy, resiliency, and optimism can be extended into the well-being domain. Although PsyCap has been clearly demonstrated to be related to employee attitudes, behaviors, and performance, linking it with other life domains relevant to overall well-being has yet to be tested. After first building a comprehensive conceptual foundation for extending PsyCap …

Dietary Supplementation With Pollen Enhances Survival And Collembola Boosts Fitness Of A Web-Building Spider, Jason M. Schmidt, Julie A. Peterson, Jonathan Lundgren, James D. Harwood

Department of Entomology: Faculty Publications

Uncertainties exist about the value of non-prey food for predators that are commonly food-limited, and the dietary conditions where non-prey foods are beneficial for carnivorous species. Prior studies show that large quantities of pollen grains are intercepted in the webs of web-building spiders. We examined the nutritional benefits of pollen as a non-prey food for a common ground-dwelling, sheet web-building spider, Mermessus fradeorum (Berland) (Araneae: Linyphiidae). These predators were provided diets of prey or no prey in the presence and absence of pollen. Treatment effects were quantified by measuring predator body nutrient composition, survival, body size, and offspring production. Per …

Bacillus Thuringiensis: Transgenic Crops, Julie A. Peterson, John J. Obrycki, James D. Harwood

Department of Entomology: Faculty Publications

Bacillus thuringiensis (Bt) crops, genetically modified to express insecticidal toxins that target key pests of corn, cotton, rice, potato, and other crops, have been rapidly adopted and have become dominant fixtures in agroecosystems throughout the world. Due to the constitutive nature of Bt toxin expression, insecticidal proteins may be found in nearly all plant tissues, presenting multiple sources for Bt toxins to enter the environment, thus creating complex direct and indirect pathways for non-target organisms to be exposed to insecticidal proteins. The environmental impacts of Bt crops have been widely debated, although both benefits and risks do exist. Benefits of …

Why Can’T Rodents Vomit? A Comparative Behavioral, Anatomical, And Physiological Study, Charles C. Horn, Bruce A. Kimball, Hong Wang, James Kaus, Samuel Dienel, Allysa Nagy, Gordon R. Gathright, Bill J. Yates, Paul L. R. Andrews

United States Department of Agriculture Wildlife Services: Staff Publications

The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats and mice appear to lack this response. It is unclear whether these rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or lack of key neural circuits. Moreover, it is unknown whether laboratory rodents are representative of Rodentia with regards to this reflex. Here we conducted behavioral testing of members of all three major groups of Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), and squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine (sc), …

Den Attendance Patterns In Swift Foxes During Pup Rearing: Varying Degrees Of Parental Investment Within The Breeding Pair, Sharon A. Poessel, Eric M. Gese

United States Department of Agriculture Wildlife Services: Staff Publications

Parental investment varies inmammalian species, with male care of young being more common in social and monogamous species. Monogamy is commonly observed in canid species, with both males and females, and often ‘‘helper’’ individuals, providing some degree of care for the young. Social units of the swift fox (Vulpes velox), a small North American canid species, usually consist of a male– female pair and occasionally helpers. The role of parental investment and behavior in swift fox society is currently poorly understood. We observed swift fox dens during the pup-rearing season in each of 2 years to evaluate attendance …

Agricultural Innovation To Protect The Environment, Jeffrey Sayer, Kenneth Cassman

Department of Agronomy and Horticulture: Faculty Publications

In a world of 9.5 billion people, global demand for food, fiber, and biofuels has to be met with minimal possible increases in land, water, fossil fuels, and the minerals used to produce fertilizers (1–4). The problem is debated at three levels: first, that agriculture will not be able to produce enough because it will come up against both biophysical and environmental limits that restrict yields (3, 5, 6); second, that the need to expand and intensify agriculture will destroy the broader environmental values of forests, wetlands, marine systems, and their associated biodiversity (7–9); and third, that there are institutional …

Maternal Environment Effects On Phenolic Defenses In Abutilon Theophrasti Seeds, Brian J. Schutte, Sam E. Wortman, John L. Lindquist, Adam S. Davis

Department of Agronomy and Horticulture: Faculty Publications

A class of phenolic compounds, ortho-dihydroxyphenols (hereafter “o-DHP”), has been implicated with seed survival. Based on expectations of the growth-differentiation balance hypothesis, we predicted that seed o-DHP concentration exhibits a curvilinear response to increasing resource availability in the maternal environment, with maximum o-DHP occurring at moderate resource levels. To test this hypothesis, Abutilon theophrasti seeds were produced under field conditions at two locations. Each location included twelve maternal environments established through factorial combinations of soil compost (+/−), species assemblage (A. theophrasti with and without maize), and soil nitrogen fertilizer (0, 0.5× or 1× local …