Digital Commons Network^™

Production Of Fine Nd-Fe-B Alloy Powder By Pulsed Plasma Atomization, Jeffrey E. Shield, S. Christensen, R. W. Kincaid, F. D. Witherspoon

Department of Mechanical and Materials Engineering: Faculty Publications

Extremely fine (<10 >μm) Nd-Fe-B powder was generated by pulsed plasma atomization processing. The number average was just over 3 μm, as determined by computer-assisted scanning electron microscopy analysis of almost 3000 particles. Despite the fine particle size, alloys of stoichiometric Nd₂Fe₁₄B resulted in the properitectic formation of α-Fe, deleteriously affecting the magnetic properties. Nevertheless, this work shows the possibility of generating extremely fine, isotropic powder for bonded and hybrid magnet applications.

Use Of A Seed Scarifier For Detection And Enumeration Of Galls Of Anguina And Rathayibacter Species In Orchard Grass Seed, Steven C. Alderman, Douglas M. Bilsland, John A. Griesbach, Gene M. Milbrath, Norman W. Schaad, Elena Postnikova

Department of Plant Pathology: Faculty Publications

Seed galls, caused by Anguina spp., are normally detected visually in cereals such as wheat and barley. However, in grasses such as orchard grass, the presence of galls induced by Anguina or Rathayibacter spp. are difficult to detect visually due to their infrequent occurrence and masking by lemmas and paleas. To develop improved seed assays for the presence of the nematode and bacterial galls, a small scarifier was used to remove lemmas and paleas without causing major damage to seeds or galls. Following scarification, the galls were visually identified and manually counted under a dissecting microscope. Using the scarifier, several …

Evaluation Of Resistance Screening Methods For Sclerotinia Stem Rot Of Soybean And Dry Bean, Linda S. Kull, Tri D. Vuong, Kris S. Powers, Kent M. Eskridge, James R. Steadman, Glen L. Hartman

Department of Plant Pathology: Faculty Publications

Three methods to identify levels of resistance to Sclerotinia sclerotiorum in soybean (Glycine max) and dry bean (Phaseolus vulgaris) were compared using multiple data analyses. The three methods were mycelial plug inoculations of cotyledons, cut stems, and detached leaves. Six S. sclerotiorum isolates of known relative aggressiveness were inoculated on each of three soybean and dry bean cultivars with varied response to S. sclerotiorum. For soybean, all three inoculation methods accurately identified isolate aggressiveness irrespective of cultivar, but identification of susceptible and partially resistant soybean cultivars was influenced by isolate. For dry bean, the cotyledon and cut …

Osmosensitive Taurine Release: Does Taurine Share The Same Efflux Pathway With Chloride And Other Amino Acid Osmolytes?, Rodrigo Franco

School of Veterinary and Biomedical Sciences: Faculty Publications

Swelling subsequent to hyposmotic conditions activates a process of volume regulation present in most cell types. This volume adjustment is accomplished by osmolyte translocation toward the extracellular space to reach a new osmotic equilibrium. Molecules involved in this homeostatic mechanism have been broadly classified into two categories: organic and inorganic osmolytes. Inorganic osmolytes comprise mainly the intracellular ions K⁺ and Cl^–. Cell swelling–induced activation of separate K⁺ and Cl^– channels has been described in most preparations. Organic osmolytes are grouped in three categories: amino acids, polyalcohols, and methylamines. These osmolytes, particularly taurine, are present in …

Role Of Activator Protein-1 In The Down-Regulation Of The Human Cyp2j2 Gene In Hypoxia, Nicole Y. Marden, Eva Fiala-Beer, Shi-Hua Xiang, Michael Murray

School of Veterinary and Biomedical Sciences: Faculty Publications

The cytochrome P450 (CYP) 2J2 arachidonic acid epoxygenase gene was down-regulated at a pre-translational level in human hepatoma-derived HepG2 cells incubated in a hypoxic environment; under these conditions, the expression of c-Jun and c-Fos mRNA and protein was increased. The 5′-upstream region of the CYP2J2 gene was isolated by amplification of a 2341 bp fragment and putative regulatory elements that resembled activator protein-1 (AP-1)-like sequences were identified. From transient transfection analysis, c-Jun was found to strongly activate a CYP2J2–luciferase reporter construct, but co-transfection with plasmids encoding c-Fos or c-Fos-related antigens, Fra-1 and -2, abrogated reporter activity. Using a series …

Mucosal Priming Of Simian Immunodeficiency Virus-Specific Cytotoxic T-Lymphocyte Responses In Rhesus Macaques By The Salmonella Type Iii Secretion Antigen Delivery System, David T. Evans, Li-Mei Chen, Jacqueline Gillis, Kuei-Chin Lin, Brian Harty, Gail P. Mazzara, Ruben O. Donis, Keith G. Mansfield, Jeffrey D. Lifson, Ronald C. Desrosiers, Jorge E. Galán, R. Paul Johnson

School of Veterinary and Biomedical Sciences: Faculty Publications

Nearly all human immunodeficiency virus (HIV) infections are acquired mucosally, and the gut-associated lymphoid tissues are important sites for early virus replication. Thus, vaccine strategies designed to prime virus-specific cytotoxic T lymphocyte (CTL) responses that home to mucosal compartments may be particularly effective at preventing or containing HIV infection. The Salmonella type III secretion system has been shown to be an effective approach for stimulating mucosal CTL responses in mice. We therefore tested ∆phoP-phoQ attenuated strains of Salmonella enterica serovar Typhimurium and S. enterica serovar Typhi expressing fragments of the simian immunodeficiency virus (SIV) Gag protein fused to the …

Method To Detect The Presence Of A Microorganism Or Agent In An Animal, David R. Smith, Laura L. Hungerford, Rodney A. Moxley, Susanne Hinkley, Terry Klopfenstein, Jeff Gray

School of Veterinary and Biomedical Sciences: Faculty Publications

The present invention provides a method to detect the presence of a microorganism or agent in an animal. The method encompasses placement of devices at various locations where the animal resides so as to induce the animal to initiate contact with the device. As a result of this contact, the animal deposits various microorganisms and agents on the device. The device is then tested for the presence of the particular microorganism or agent of interest.

Duration Of Infection And Proportion Of Pigs Persistently Infected With Porcine Reproductive And Respiratory Syndrome Virus, Robert W. Wills, Alan R. Doster, Judith A. Galeota, Jung-Hyang Sur, Fernando A. Osorio

Nebraska Center for Virology: Faculty Publications

Understanding the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) persistence in individual pigs is essential to the development of successful control programs. The objectives of this study were to investigate the proportion of inoculated pigs that become persistently infected with PRRSV and the duration of their infection. Additionally, different diagnostic techniques that detect persistent infections were compared. Twenty-eight 35-day-old pigs were inoculated with PRRSV. Serum and tonsil biopsy samples were collected on days 0, 7, 14, and 28 and then approximately monthly thereafter until day 251 post-inoculation (p.i.). Tonsil, lymph node, and lung samples were collected following euthanasia …

The Coat Protein Of Turnip Crinkle Virus Suppresses Posttranscriptional Gene Silencing At An Early Initiation Step, Feng Qu, Tao Ren, Thomas Jack Morris

Nebraska Center for Virology: Faculty Publications

Posttranscriptional gene silencing (PTGS), or RNA silencing, is a sequence-specific RNA degradation process that targets foreign RNA, including viral and transposon RNA for destruction. Several RNA plant viruses have been shown to encode suppressors of PTGS in order to survive this host defense. We report here that the coat protein (CP) of Turnip crinkle virus (TCV) strongly suppresses PTGS. The Agrobacterium infiltration system was used to demonstrate that TCV CP suppressed the local PTGS as strongly as several previously reported virus-coded suppressors and that the action of TCV CP eliminated the small interfering RNAs associated with PTGS. We have also …

Roles Of Mycobacterium Smegmatis D-Alanine:D-Alanine Ligase And D-Alanine Racemase In The Mechanisms Of Action Of And Resistance To The Peptidoglycan Inhibitor D-Cycloserine, Zhengyu Feng, Raul G. Barletta

School of Veterinary and Biomedical Sciences: Faculty Publications

D-Cycloserine (DCS) targets the peptidoglycan biosynthetic enzymes D-alanine racemase (Alr) and Dalanine: D-alanine ligase (Ddl). Previously, we demonstrated that the overproduction of Alr in Mycobacterium smegmatis determines a DCS resistance phenotype. In this study, we investigated the roles of both Alr and Ddl in the mechanisms of action of and resistance to DCS in M. smegmatis. We found that the overexpression of either the M. smegmatis or the Mycobacterium tuberculosis ddl gene in M. smegmatis confers resistance to DCS, but at lower levels than the overexpression of the alr gene. Furthermore, a strain overexpressing both the alr and ddl …

Herpes Simplex Virus Type 1 And Bovine Herpesvirus 1 Latency, Clinton J. Jones

School of Veterinary and Biomedical Sciences: Faculty Publications

A high percentage of the world’s population are infected with herpes simplex virus type 1 (HSV-1), and infection can cause a variety of disorders (35, 187). Recurrent ocular HSV-1 is the leading cause of infectious corneal blindness in industrialized nations (190). In a murine model, ocular infection induces autoimmune disorders, leading to corneal antigen destruction and stromal keratitis (275). HSV-1 infections also cause gastrointestinal disorders, esophageal disorders, and approximately 25% of the genital herpes infections (67, 158). HSV-1 infections can cause sporadic encephalitis, but this is relatively rare compared to other diseases resulting from infection. Further evidence for its involvement …

Combined Kerr Microscope And Magnetic Force Microscope For Variable Temperature Ultrahigh Vacuum Investigations, D. Peterka, Axel Enders, G. Haas, Klaus Kern

Axel Enders Publications

A new system combining a Kerr microscope and a magnetic force microscope for the study of magnetic domains in ultrathin films under ultrahigh vacuum conditions is presented. Due to the overlapping imaging range of both techniques magnetic domains can be investigated over a lateral range from millimeter down to fractions of a micrometer. Experiments can be done at variable temperatures, from 80 K to 600 K. First results are presented showing the same magnetic domain in a three monolayer Fe film on Cu (100) imaged with both techniques.

Light Storage With Light Of Arbitrary Polarization, Hong Gao, Mark Rosenberry, Herman Batelaan

Department of Physics and Astronomy: Faculty Publications

We have demonstrated the phase coherence of stored light in Rb vapor with a completely optical technique. Combining this technique with polarization measurements provides strong evidence that arbitrary polarizations can be stored. The fidelity obtained exceeds 95% for all polarizations. We view the capability to store polarizations as a first step towards building a quantum memory in such a system.

Multiphoton Detachment Of A Negative Ion By An Elliptically Polarized, Monochromatic Laser Field, N. L. Manakov, M. V. Frolov, Bogdan Borca, Anthony F. Starace

Anthony F. Starace Publications

The quasistationary quasienergy state approach (QQES) is applied to the analysis of partial (n-photon) decay rates and angular distributions (ADs) of photoelectrons produced by an elliptically polarized laser field. The problem is formulated for a weakly bound electron with an energy E₀ in the three-dimensional δ-model potential (which approximates the short-range potential of a negative ion) interacting with a strong monochromatic laser field having an electric vector F(ωt).The results presented cover weak (perturbative), strong (nonperturbative), and superstrong field regimes as well as a wide interval of frequencies ω extending from the tunnelling (ħω << |E_{0 …}

Spin-Dependent Tunneling In Magnetic Tunnel Junctions, Evgeny Y. Tsymbal, O. N. Mryasov, Patrick R. Leclair

Evgeny Tsymbal Publications

The phenomenon of electron tunneling has been known since the advent of quantum mechanics, but continues to enrich our understanding of many fields of physics, as well as creating sub-fields on its own. Spin-dependent tunneling in magnetic tunnel junctions (MTJs) has recently aroused enormous interest and has developed in a vigorous field of research. The large tunneling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible applications in non-volatile random access memories and next-generation magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of spindependent tunneling. In this review article we present an …

Monitoring Trends In Bat Populations Of The United States And Territories: Status Of The Science And Recommendations For The Future, Thomas J. O'Shea, Michael A. Bogan, Laura E. Ellison

United States Geological Survey: Staff Publications

Populations of bats (Order Chiroptera) are difficult to monitor. However, current recognition of the importance of bats to biodiversity, their ecological and economic value as ecosystem components, and their vulnerability to declines makes monitoring trends in their populations a much-needed cornerstone for their future management. We report findings and recommendations of a recent expert workshop on monitoring trends in bat populations in the United States and territories. We summarize selected case reports presented by others at the workshop, including reviews of methods and ongoing efforts to monitor a wide range of species of bats in a diverse array of situations. …

Public Knowledge And Perceptions Of Black-Tailed Prairie Dogs, Berton Lee Lamb, Kurt Cline

United States Geological Survey: Staff Publications

Black-tailed prairie dogs (Cynomys ludovicianus) historically occupied an 11-state region of the United States. We surveyed 1,900 residents (response rate 56%) of this region to understand citizen knowledge and perceptions about prairie dogs and their management. Those who have direct experience— e.g., those who live very close to prairie dog colonies or know the location of the nearest colony—have higher levels of knowledge. A significantly higher level of knowledge was documented among those who were politically active when compared with the general public. Those who found environmental issues difficult to understand were associated with lower knowledge. People with …

Nebraska Birds In Recorded History, Fritz L. Knopf

United States Geological Survey: Staff Publications

The critical image of historical perspective is lacking in much of conservation biology's dialogue on protecting biotic diversity. Some biologists offer that the vision for bird conservation on the Central Grasslands of North America is to secure at least fragments of the avian assemblage that coexisted with Native Americans when Europeans first arrived. Nowhere, however, has anyone really tried to re-create such a historical image in any biological arena, until now.

Differences In Habitat Use By Blanding’S Turtles, Emydoidea Blandingii, And Painted Turtles, Chysemys Picta, In The Nebraska Sandhills, R. Bruce Bury, David J. Germano

United States Geological Survey: Staff Publications

We sampled a variety of wetlands in the Nebraska sandhills at Valentine National Wildlife Refuge. Significantly more individuals of painted turtles (Chrysemys picta) occurred in lakes and open waters than in marshes or small ponds, and the opposite was true for Blanding’s turtles (Emydoidea blandingii). Besides this marked difference in habitat use, 46% of the captured E. blandingii in pond/marsh habitat were juveniles, but only 31.6% in lakes and open water. Current information suggests that marshes and small ponds are important habitat for juvenile turtles, especially Emydoidea blandingii.

Eolian Sand Transport Pathways In The Southwestern United States: Importance Of The Colorado River And Local Sources, Daniel R. Muhs, Richard L. Reynolds, Josh Been, Gary Skipp

United States Geological Survey: Staff Publications

Geomorphologists have long recognized that eolian sand transport pathways extend over long distances in desert regions. Along such pathways, sediment transport by wind can surmount topographic obstacles and cross major drainages. Recent studies have suggested that three distinct eolian sand transport pathways exist (or once existed) in the Mojave and Sonoran Desert regions of the southwestern United States. One hypothesized pathway is eolian sand transport from the eastern Mojave Desert of California into western Arizona, near Parker, and would require sand movement across what must have been at least a seasonally dry Colorado River valley. We tested this hypothesis by …

Agriculture -Related Science And Technology Priorities For Poverty Reduction And Sustainable Development In Developing Countries To 2020, Kenneth G. Cassman

Department of Agronomy and Horticulture: Faculty Publications

Alleviation of poverty in developing countries depends on four factors: (1) supportive political, social, and economic environments that foster investments in infrastructure, enterprises, markets, and natural resource conservation, (2) sustainable development and income growth, (3) a continued decline in population growth rates such that the human population ultimately stabilizes at about 9-10 billion people by 2050, (4) access to affordable and nutritious food supply. Of these, the CGIAR system of research centers have a comparable advantage in contributing to sustainable development and income growth by ensuring adequate food production in systems that conserve natural resources and protect environmental quality. To …

Variability And Relationships Among 12-Hour Ivdmd, Starch, Oil, Protein, And Physical Characteristics Of 16 Sorghum Conversion Lines, Jeffrey F. Pedersen, Kenneth D. Kofoid

Department of Agronomy and Horticulture: Faculty Publications

A factor frequently identified as a key to understanding sorghum [Sorghum bicolor (L.) Moench] feed value to ruminant animals is rate of starch digestion. Recent research in corn (Zea mays L.) has established a strong ability to predict rumen starch degradation from grain physical and chemical parameters. It was therefore important to determine whether similar relationships could be established in sorghum. The objectives of this study were to determine: 1) range of variation for 12-hour in vitro dry matter disappearance (IVDMD), chemical, and physical grain quality parameters among 16 sorghum conversion lines; and 2) to establish the strength …

Understanding Corn Yield Potential In Different Environments, Achim R. Dobermann, Timothy J. Arkebauer, Kenneth G. Cassman, Rhae A. Drijber, J. Lindquist, James E. Specht, Daniel T. Walters, Haishun Yang, D. Miller, Darren L. Binder, Gregory Teichmeier, Richard B. Ferguson, Charles S. Wortmann

Department of Agronomy and Horticulture: Faculty Publications

The UNL research program on Ecological intensification of irrigated maize-based cropping systems aims to (i) improve understanding of the yield potential of corn and soybean and how it is affected by management, (ii) develop a scientific basis for evaluating yield potential at different locations, (iii) develop practical technologies for managing intensive cropping systems at 70-80% of the yield potential, and (iv) conduct integrated assessment of productivity, profitability, input use efficiency, soil carbon sequestration, energy and carbon budgets, and trace gas emissions. Results of this work have been reported earlier (Arkebauer et al., 2001; Dobermann et al., 2002). In this paper …

Influence Of Nitrogen And Duration Of Weed Interference On Corn Growth And Development, Sean P. Evans, Stevan Z. Knezevic, John L. Lindquist, Charles A. Shapiro

Department of Agronomy and Horticulture: Faculty Publications

An improved understanding of the effects of nitrogen (N) on crop–weed interactions is needed for the development of integrated weed management systems where responsible use of N fertilizers is considered. Field experiments conducted in 1999 and 2000 at two locations in eastern Nebraska quantify the effects of N and increasing duration of weed interference on corn growth and development. A naturally occurring population of weeds was allowed to compete with the corn crop for increasing lengths of time and at three rates of N application (0, 60, and 120 kg N ha^-1). Weed interference and withholding applied N …

Nitrogen Application Influences The Critical Period For Weed Control In Corn, Sean P. Evans, Stevan Z. Knezevic, John L. Lindquist, Charles A. Shapiro, Erin E. Blankenship

Department of Agronomy and Horticulture: Faculty Publications

The critical period for weed control (CPWC) is the period in the crop growth cycle during which weeds must be controlled to prevent unacceptable yield losses. Field studies were conducted in 1999 and 2000 in eastern Nebraska to evaluate the influence of nitrogen application on the CPWC in dryland corn in competition with a naturally occurring weed population. Nitrogen fertilizer was applied at rates equivalent to 0, 60, and 120 kg N ha^-1. A quantitative series of treatments of both increasing duration of weed interference and length of weed-free period were imposed within each nitrogen main plot. The …

The S-Locus And Unilateral Incompatibility, C. Nathan Hancock, Katsuhiko Kondo, Brian Beecher, Bruce Mcclure

Department of Agronomy and Horticulture: Faculty Publications

Plants have many ways to regulate the type of pollen that arrives on the stigma surface. Once there, further control mechanisms regulate compatibility. The latter controls are largely based on biochemical interactions that support compatible pollination and prevent incompatible matings. S-RNase-based selfincompatibility (SI) systems are the most phylogenetically widespread mechanisms for controlling pollination. Studies of Nicotiana establish a firm link between SI and unilateral interspecific incompatibility. Although implicated in both inter- and intraspecific compatibility, S-RNase operates through at least three distinct genetic mechanisms that differ in their dependence on non-S-RNase factors. Identification and characterization of these non-S-RNase factors is currently …

Comparison And Hybridization Of Two Approaches For Maize Simulation, Haishun Yang, Kenneth G. Cassman, Achim R. Dobermann, Daniel T. Walters, John L.. Lindquist, Timothy J. Arkebauer

Department of Agronomy and Horticulture: Faculty Publications

Two approaches dominate simulation modeling of maize growth: (1) a generic approach, represented by the family of crop models developed by Dutch scientists at the Wageningen University, e.g. SUCROS (Spitters et al, 1989), WOFOST (Diepen et al, 1989) and INTERCOM (Kropff and van Laar, 1993), and (2) a maize-specific approach, represented by CERES-Maize (Jones and Kiniry, 1986) and its derivatives such as the maize module in DSSAT, and the MSB model developed by Muchow et al. (Muchow et al, 1990). These two approaches differ in three aspects. First, maize development in generic models is driven primarily by availability of …

Growing Corn In A Computer: The Hybrid Hybrid-Maize Simulation Model And Its Application To Production Agriculture, Achim R. Dobermann, Haishun Yang

Department of Agronomy and Horticulture: Faculty Publications

Outline

Yield potential and yield gaps

To achieve yield potential of an environment

Hybrid Hybrid-Maize model

Hybrid Hybrid-Maize validation

Potential applications

EI Lincoln, NE: 2003 Yields

What determines spatial variation in corn yield potential in Nebraska?

Simulated attainable corn yields in different regions of Nebraska

To achieve full climatic site yield potential, management requires:

Optimal management: gain in season length

Corn yield potential in 2003

Potential applications

Summary

Outlook

Genetic And Environmental Effects On Dough Mixing Characteristics And Agronomic Performance Of Diverse Hard Red Winter Wheat Genotypes, Hikmet Budak, P. Stephen Baenziger, Robert A. Graybosch, B. S. Beecher, Kent M. Eskridge, M. J. Shipman

Department of Agronomy and Horticulture: Faculty Publications

Wheat (Triticum aestivum L.) genotypes with short mixing times usually have low mixing tolerance values, which make them more ,sensitive to over mixing in commercial bread production. In this study, we evaluated the genotypic and environmental effects on agronomic performance and end-use quality of 27 experimental genotypes (hereafter referred to as mixing tolerant genotypes) which were identified in an initial screen as having short mixing times and good mixing tolerances to 1) determine whether genotypes identified in a preliminary end-use quality screen as lines with usually long tolerances but short mixing times were due to their genotype (G), the …

Nutrition Of Floricultural Crops: How Far Have We Come?, Ellen T. Paparozzi

Department of Agronomy and Horticulture: Faculty Publications

According to Seeley (1979), even though the Society for Horticultural Science was formed in 1903, it wasn't until the 1930s that research papers on the subject of floriculture were published in our journal. There were, however, numerous college and university bulletins about floricultural crops which included fertilizer studies (for example, Blake, 1915).

Despite the sluggish start, in the last 25 years, in the American Society of Horticultural Science's three journals (Journal of the American Society for Horticultural Science, HortScience, and HortTechnology) alone, there have been over 240 publications relating to the nutrition of floricultural crops. Journal such as …