Digital Commons Network^™

Einstein’S Impact On Optics At The Frontier, Donald Umstadter

Donald Umstadter Publications

The seminal contributions made by Einstein a century ago have enabled a new frontier area of science, called high-field science. This research involves the physics of the interactions of matter with electromagnetic fields at its highest levels ever achieved in the laboratory. Besides being of fundamental importance to physics research, the discoveries being made in this area are also leading to a new generation of compact and ultrashort-duration particle accelerators and X-ray light sources, with applications ranging from nuclear fusion to cancer therapy.

Fundamental Contribution Of Β-Oxidation To Polyketide Mycotoxin Production In Planta, Lori A. Maggio-Hall, Richard A. Wilson, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

Seed contamination with polyketide mycotoxins, including aflatoxin (AF) and sterigmatocystin (ST) produced by Aspergillus spp., is an agricultural, economic, and medical issue worldwide. Acetyl-CoA, the fundamental building block of all known fungal polyketides, is generated by a large number of biochemical pathways, including β-oxidation of fatty acids and glycolysis of sugars. We present several lines of evidence to support a major role for seed fatty acids in formation of AF and ST in A. flavus, A. parasiticus, and A. nidulans. Aspergillus strains exhibiting canonical signs of oleic acid–induced peroxisome proliferation, including increased catalase activity, β-oxidation gene expression, and …

Genome Sequences Of Agropyron Mosaic Virus And Hordeum Mosaic Virus Support Reciprocal Monophyly Of The Genera Potyvirus And Rymovirus In The Family Potyviridae, Roy C. French, D.C. Stenger

Department of Plant Pathology: Faculty Publications

Assignment of mite-transmitted species to the genus Rymovirus (family Potyviridae) has changed several times, and the status of the genus has been questioned. To address this issue, complete genome sequences of the rymoviruses Agropyron mosaic virus (AgMV) and Hordeum mosaic virus (HoMV) were determined. AgMV (9540 nucleotides) and HoMV (9463 nucleotides) each encode a single polyprotein with proteinase cleavage sites demarcating protein products characteristic of monopartite species of the family Potyviridae. Of the described species of Potyviridae, AgMV and HoMV are most closely related to each other (68.5% nucleotide and 71.6% amino acid sequence identity) and equidistant …

Thucydides [From Encyclopedia Of Social Measurement], Peter A. Furia, Ari Kohen

Department of Political Science: Faculty Publications

Thucydides (5th Century B.C.E.) is arguably the first person to engage in systematic social measurement. His lone surviving masterwork. The Peloponnesian War, stands as a founding text for the disciplines of history and political science. On its surface, The Peloponnesian War comprehensively and objectively chronicles the 27 year military struggle between Athens and Sparta from which the latter emerged victorious in 404 B.C.E. Yet Thucydides’ aim and approach in recounting the Peloponnesian War is extensively debated, often reflecting enduring disagreements about the philosophy and methodology of social science.

Natural History And Karyology Of The Yucatán Vesper Mouse, Otonyctomys Hatti, Hugh H. Genoways, Robert M. Timm, Mark D. Engstrom

University of Nebraska State Museum: Mammalogy Papers

Seventeen specimens of the rare Yucatán vesper mouse, Otonyctomys hatti, are now known from Belize, Guatemala, and the Mexican states of Campeche, Quintana Roo, and Yucatán. We herein report a second specimen of O. hatti, from Belize, extending the known geographic range of the species 95 km to the southeast in the country. This is the first location at which O. hatti has been taken sympatrically with the Central American vesper mouse, Nyctomys sumichrasti. We also report data on three additional specimens of O. hatti from Campeche. Nyctomys and Otonyctomys share similar habits and habitat requirements, and …

Functional Consequences Of Genome Evolution In Listeria Monocytogenes: The Lmo0423 And Lmo0422 Genes Encode ΣC And Lstr, A Lineage Ii-Specific Heat Shock System, Chaomei Zhang, Joseph Nietfeldt, Min Zhang, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

Listeria monocytogenes strains belonging to phylogenetic lineage II (serotypes 1/2a, 1/2c, and 3a) carry a lineage-specific genome segment encoding a putative sigma subunit of RNA polymerase (lmo0423, herein referred to as sigC), a gene of unknown function (lmo0422) similar to the padR family of regulators, and a gene that is similar to the rodA-ftsW family of cell wall morphology genes (lmo0421). To understand the function of this set of genes, their expression patterns and the effects of null mutations in the lineage II L. monocytogenes strain 10403S were examined. The data are consistent with the three genes comprising an …

Patterns Of Covariance Between Forest Stand And Canopy Structure In The Pacific Northwest, Michael A. Lefsky, Andrew T. Hudak, Warren B. Cohen, Steve Acker

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

In the past decade, lidar (light detection and ranging) has emerged as a powerful tool for remotely sensing forest canopy and stand structure, including the estimation of aboveground biomass and carbon storage. Numerous papers have documented the use of lidar measurements to predict important aspects of forest stand structure, including aboveground biomass. Other papers have documented the ability to transform lidar measurements to approximate common field measures, such as cover, stand height, and vertical distributions of foliage density and light transmittance. However, only a small number of existing works have thoroughly examined relationships between comprehensive assemblages of forest canopy and …

Geographic Variability In Lidar Predictions Of Forest Stand Structure In The Pacific Northwest, Michael A. Lefsky, Andrew T. Hudak, Warren B. Cohen, S.A. Acker

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Estimation of the amount of carbon stored in forests is a key challenge for understanding the global carbon cycle, one which remote sensing is expected to help address. However, carbon storage in moderate to high biomass forests is difficult to estimate with conventional optical or radar sensors. Lidar (light detection and ranging) instruments measure the vertical structure of forests and thus hold great promise for remotely sensing the quantity and spatial organization of forest biomass. In this study, we compare the relationships between lidar measured canopy structure and coincident field measurements of forest stand structure …

Soil Feedback And Pathogen Activity In Prunus Serotina Throughout Its Native Range, Kurt O. Reinhart, Alejandro A. Royo, Wim H. Van Der Putten, Keith Clay

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

1. Oomycete soil pathogens are known to have a negative effect on Prunus serotina seedling establishment and to promote tree diversity in a deciduous forest in Indiana, USA. Here, we investigate whether negative feedbacks operate widely in its native range in eastern USA.

2. In laboratory experiments, soil sterilization was used to test the net effect of soil biota (pathogens and mutualists) and fungicide treatments to test the effects of soil pathogens (oomycetes) on survival of P. serotina seedlings in soils from 22 P. serotina populations throughout the eastern USA.

3. In soil associated with P. serotina trees, there was …

Field Assessment Of The Risk Posed By Diorhabda Elongata, A Biocontrol Agent For Control Of Saltcedar (Tamarix Spp.), To A Nontarget Plant, Frankenia Salina, Tom L. Dudley, David J. Kazmer

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

The biological control program for saltcedar (Tamarix spp.) has led to open releases of a specialist beetle (Chrysomelidae: Diorhabda elongata) in several research locations, but the controversy over potential impacts to native, nontarget plants of the genus Frankenia remains unresolved. To assess the potential for nontarget impacts under Weld conditions, we installed cultivated Frankenia spp. (primarily two forms of Frankenia salina but also including Frankenia jamesii) at locations in Nevada and Wyoming where D. elongata densities and saltcedar defoliation were expected to be very high, so insects would be near starvation with high probability of attacking nontargets …

Weed Suppression By Deleterious Rhizobacteria Is Affected By Formulation And Soil Properties, Robert E. Zdor, Carlene M. Alexander, Robert J. Kremer

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

Deleterious rhizobacteria (DRB) suppress weed growth in field tests and are considered potential weed biological control agents. This study compared the relative inhibitory action of the DRB Pseudomonas fluorescens strain G2-11 in different formulations, corn gluten meal (CGM), and semolina flour, toward wheat (Triticum aestivum L.), green foxtail (Setaria viridis (L.) Beauv.), and velvetleaf (Abutilon theophrasti Medik) seeds and seedlings in soil assays. Strain G2-11 successfully established in semolina flour as an inoculum formulation but was incompatible with CGM presumably because of antibacterial factors present. The effect of DRB and plant products on seed germination and plant …

Topographic, Bioclimatic, And Vegetation Characteristics Of Three Ecoregion Classification Systems In North America: Comparisons Along Continent-Wide Transects, Robert Thompson, Sarah Shafer, Katherine Anderson, Laura Strickland, Richard Pelltier, Patrick Bartlein, Michael Kerwin

United States Geological Survey: Staff Publications

Ecoregion classification systems are increasingly used for policy and management decisions, particularly among conservation and natural resource managers. A number of ecoregion classification systems are currently available, with each system defining ecoregions using different classification methods and different types of data. As a result, each classification system describes a unique set of ecoregions. To help potential users choose the most appropriate ecoregion system for their particular application, we used three latitudinal transects across North America to compare the boundaries and environmental characteristics of three ecoregion classification systems [Küchler, World Wildlife Fund (WWF), and Bailey]. A variety of variables were used …

Gender Differences In Social Support For Socially Anxious Individuals, Lindsay Ham, Sarah A. Hayes, Debra A. Hope

Department of Psychology: Faculty Publications

Given that social anxiety disorder is a common, chronic, debilitating disorder and socially anxious women appear to have different experiences related to social development and social support than men, it is essential that the gender differences in social anxiety and social support be understood. The present study examined perceived social support quantity and satisfaction in 23 women and 28 men seeking treatment for social anxiety disorder. Contrary to expectations, men and women did not differ on measures of social support. However, younger, unmarried women reported having smaller social support networks and less satisfaction with their social support networks than older, …

Pound, Nathan Roscoe (1870-1964), Michael R. Hill

Department of Sociology: Faculty Publications

Roscoe Pound was born on 27 October 1870 in Lincoln, Nebraska. He was classically trained in languages and the sciences at the University of Nebraska and received the BA degree in 1888. Pound’s innovative graduate studies in botany under the tutelage of Charles E. Bessey, resulted in a doctoral dissertation written jointly with Frederic E. Clements, published in 1898, on The Phytogeography of Nebraska. The Phytogeography established the American school of plant ecology (Tobey 1981) and for his part Pound received the first Nebraska PhD earned “in course” in 1899. Already a member of Phi Beta Kappa and Sigma …

Participant Observations On Environmental And Social Eff Ect S Of The Conservation Reserve Program: Results Of A National Survey, Arthur W. Alen

United States Geological Survey: Staff Publications

A national survey of Conservation Reserve Program (CRP) contractees was completed to obtain information about environmental and social effects of the program on participants, farms, and communities. Over 75% of respondents believed CRP benefits to wildlife were important. Seventy-three percent of respondents observed increased numbers of wildlife associated with CRP lands. A majority of respondents (82%) believed the amount of assistance furnished by the U.S. Department of Agriculture related to planning and maintaining wildlife habitat associated with CRP lands was appropriate. The majority of respondents reported CRP benefits, including increased quality of surface and ground waters, improved air quality, control …

Paleoceanographic History Of The Guaymas Basin, Gulf Of California, During The Past 15,000 Years Based On Diatoms, Silicoflagellates, And Biogenic Sediments, John A. Barron, David Bukrya, Walter E. Dean

United States Geological Survey: Staff Publications

High-resolution records of calcium carbonate, biogenic opal, diatoms, and silicoflagellates from western Guaymas Basin gravity core GGC55 and piston core JPC56 and eastern Guaymas Basin DSDP Site 480 reveal a complex paleoceanographic history of the central Gulf of California during the past 15,000 years. Prior to ~6.2 ka, the eastern and western Guaymas Basin proxy records were remarkably similar. After conditions similar to those of today during the Bølling–Allerod, the Younger Dryas (YD) saw a major drop in diatom production, coincident with increased calcium carbonate and tropical microfossils suggestive of El Nino-like conditions. Biosiliceous productivity began increasing during the latter …

Acquisition And Evaluation Of Thermodynamic Data For Bieberite-Moorhouseite Equilibria At 0.1 Mpa, I-Ming Chou, Robert Seal Ii

United States Geological Survey: Staff Publications

Published estimates for the equilibrium relative humidity (RH) at 25 °C for the reaction: bieberite (CoSO₄•7H₂O) = moorhouseite (CoSO₄•6H₂O) + H2O, range from 69.8 to 74.5%. To evaluate these data, the humidity-buffer technique was used to determine equilibrium constants for this reaction between 14 and 43 °C at 0.1 MPa. Reversals along fi ve humidity-buffer curves yield ln K = 18.03–6509.43/T, where K is the equilibrium constant, and T is temperature in K. The derived standard Gibbs free energy of reaction is 9.43 kJ/mol, which agrees well with several previously …

Determination Of Goslarite–Bianchite Equilibria By The Humidity-Buffer Technique At 0.1 Mpa, I-Ming Chou, Robert R. Seal Ii

United States Geological Survey: Staff Publications

Goslarite–bianchite equilibria were determined along four humidity-buffer curves at 0.1 MPa and between 27 and 36 °C. Results, based on tight reversals along each humidity buffer, can be represented by ln K (±0.005)=19.643-7015.38/T, where K is the equilibrium constant and T is temperature in K. Our data are in excellent agreement with several previous vapor-pressure measurements and are consistent with the solubility data reported in the literature. Thermodynamic analysis of these data yields 9.634 (±0.056) kJ mol^-1 for the standard Gibbs free energy of reaction, which is in good agreement with the value of 9.658 kJ mol^-1 calculated …

Geochemistry Of Sulfate Minerals In High- And Low-Temperature Environments: A Tribute To Robert O. Rye, Robert R. Seal Ii, John L. Jambor, Charles N. Alpers

United States Geological Survey: Staff Publications

This special issue is a tribute to Robert O. Rye, known as "Bob" to most, in light of his highly productive and ongoing career. Almost all of the papers in this issue are derived from topical sessions on sulfate minerals in hydrothermal and low-temperature environments. The sessions, held at the 2000 Geological Society of America meeting in Reno, NV, and sponsored jointly by the Mineralogical Society of America, the Society of Economic Geologists and the Geochemical Society, included 29 oral and 9 poster presentations. The sessions complemented a short course on the crystallography, geochemistry and environmental significance of sulfate minerals, …

U-Pb Zircon Ages And Pb Isotope Geochemistry Of Gold Deposits In The Carolina Slate Belt Of South Carolina, R. A. Ayuso, J. L. Wooden, N. K. Foley, Robert R. Seal Ii, A. K. Sinha

United States Geological Survey: Staff Publications

Volcanic rocks of the Persimmon Fork Formation host the largest known gold mines of the Carolina slate belt. U-Pb (SHRIMP) zircon ages have been obtained from rocks closely associated with pyrite-enargite-gold deposits at Brewer (quartz-topaz rhyolite breccia from the argillic alteration zone in the Brewer pit and felsic ash-flow tuff from the quartz sericite alteration zone), from the disseminated and semimassive pyrite-gold deposits at Haile (crystal lithic rhyolitic ash-flow tuffs from the Champion pit), and from the Ridgeway deposit (felsic ash-flow tuff from the stratigraphic host of the North pit gold deposit). Generally, the zircons are fine grained, fractured, and …

Winter Feeding Sites Of Hay In Round Bales As Major Developmental Sites Of Stomoxys Calcitrans (Diptera: Muscidae) In Pastures In Spring And Summer, Alberto B. Broce, Jerome Hogsette, Steven Paisley

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

The stable fly, Stomoxys calcitrans (L.), historically has been a pest of livestock in confined operations but seldom of animals on pastures or rangelands. In the past two decades, however, S. calcitrans has become a major pest of cattle and horses on pastures in the midwestern United States. Although there usually is an overabundance of diverse stable fly and house fly, Musca domestica L., larval habitats in confined livestock operations, no larval habitat for stable flies has been clearly identified in the pasture-range environment. Because the winter feeding of hay in round bales results in significant amounts of hay wastage …

Comparison Of A Novel Passive Sampler To Standard Water-Column Sampling For Organic Contaminants Associated With Wastewater Effluents Entering A New Jersey Stream, D. A. Alvarez, P. E. Stackelberg, J. D. Petty, J. N. Huckins, E. T. Furlong, S. D. Zaugg, M. T. Meyer

United States Geological Survey: Staff Publications

Four water samples collected using standard depth and width water-column sampling methodology were compared to an innovative passive, in situ, sampler (the polar organic chemical integrative sampler or POCIS) for the detection of 96 organic wastewater-related contaminants (OWCs) in a stream that receives agricultural, municipal, and industrial wastewaters. Thirty-two OWCs were identified in POCIS extracts whereas 9–24 were identified in individual water-column samples demonstrating the utility of POCIS for identifying contaminants whose occurrence are transient or whose concentrations are below routine analytical detection limits. Overall, 10 OWCs were identified exclusively in the POCIS extracts and only six solely identified in …

Selenium Impactson Razorback Sucker, Colorado River, Colorado I. Adults, Steven J. Hamilton, Kathy M. Holley, Kevin J. Buhl, Fern A. Bullard, L. Ken Weston, Susan F. Mcdonald

United States Geological Survey: Staff Publications

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effectson their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 μg/L in water, 0.1–1.4 μg/g in sediment, and 2.3–3.1 μg/g in food organisms (1.1 μg/g in commercial fish food), at Adobe Creek were 3.8 μg/L in water, 0.5–2.1 μg/g in sediment, and …

Conceptual Model Of Sediment Processes In The Upper Yuba River Watershed, Sierra Nevada, Ca, Jennifer A. Curtis, Lorraine E. Flint, Charles N. Alpers, Sarah M. Yarnell

United States Geological Survey: Staff Publications

This study examines the development of a conceptual model of sediment processes in the upper Yuba River watershed; and we hypothesize how components of the conceptual model may be spatially distributed using a geographical information system (GIS). The conceptual model illustrates key processes controlling sediment dynamics in the upper Yuba River watershed and was tested and revised using field measurements, aerial photography, and low elevation videography. Field reconnaissance included mass wasting and channel storage inventories, assessment of annual channel change in upland tributaries, and evaluation of the relative importance of sediment sources and transport processes. Hillslope erosion rates throughout the …

Characterization Of Waste Rock Associated With Acid Drainage At The Penn Mine, California, By Ground-Based Visible To Short-Wave Infrared Reflectance Spectroscopy Assisted By Digital Mapping, Irene C. Montero S., George H. Brimhall, Charles N. Alpers, Gregg A. Swayze

United States Geological Survey: Staff Publications

Prior to remediation at the abandoned Cu–Zn Penn Mine in the Foothills massive sulfide belt of the Sierra Nevada, CA, acid mine drainage (AMD) was created, in part, by the subaerial oxidation of sulfides exposed on several waste piles. To support remediation efforts, a mineralogical study of the waste piles was undertaken by acquiring reflectance spectra (measured in the visible to short-wave infrared range of light (0.35–2.5 Am) using a portable, digitally integrated pen tablet PC mapping system with differential global positioning system and laser rangefinder support. Analysis of the spectral data made use of a continuum removal and band-shape …

Biochemical Effects Of Lead, Zinc, And Cadmium From Mining On Fish In The Tri-States District Of Northeastern Oklahoma, Usa, Christopher J. Schmitt, Jeffrey J. Whyte, William G. Brumbaugh, Donald E. Tillitt

United States Geological Survey: Staff Publications

We assessed the exposure of fish from the Spring and Neosho Rivers in northeast Oklahoma, USA, to lead, zinc, and cadmium from historical mining in the Tri-States Mining District (TSMD). Fish (n = 74) representing six species were collected in October 2001 from six sites on the Spring and Neosho Rivers influenced to differing degrees by mining. Additional samples were obtained from the Big River, a heavily contaminated stream in eastern Missouri, USA, and from reference sites. Blood from each fish was analyzed for Pb, Zn, Cd, Fe, and hemoglobin (Hb). Blood also was analyzed for δ-aminolevulinic acid dehydratase …

A Curious Pellet From A Great Horned Owl (Bubo Virginianus), Neal Woodman, Carla J. Dove, Suzanne C. Peurach

United States Geological Survey: Staff Publications

One of the traditional methods of determining the dietary preferences of owls relies upon the identification of bony remains of prey contained in regurgitated pellets. Discovery of a pellet containing a large, complete primary feather from an adult, male Ring-necked Pheasant (Phasianus colchicus) prompted us to examine in detail a small sample of pellets from a Great Horned Owl (Bubo virginianus). Our analyses of feather and hair remains in these pellets documented the presence of three species of birds and two species of mammals, whereas bones in the pellets represented only mammals. This finding indicates an …

Survival And Selection Of Migrating Salmon From Capture-Recapture Models With Individual Traits, Richard W. Zabel, Tyler Wagner, James L. Congleton, Steven G. Smith, John G. Williams

United States Geological Survey: Staff Publications

Capture–recapture studies are powerful tools for studying animal population dynamics, providing information on population abundance, survival rates, population growth rates, and selection for phenotypic traits. In these studies, the probability of observing a tagged individual reflects both the probability of the individual surviving to the time of recapture and the probability of recapturing an animal, given that it is alive. If both of these probabilities are related to the same phenotypic trait, it can be difficult to distinguish effects on survival probabilities from effects on recapture probabilities. However, when animals are individually tagged and have multiple opportunities for recapture, we …

High Dispersal In A Frog Species Suggest That It Is Vulnerable To Habitat Fragmentation, W. Chris Funk, Allison E. Greene, Paul Stephen Corn, Fred W. Allendorf

United States Geological Survey: Staff Publications

Global losses of amphibian populations are a major conservation concern and have generated substantial debate over their causes. Habitat fragmentation is considered one important cause of amphibian decline. However, if fragmentation is to be invoked as a mechanism of amphibian decline, it must first be established that dispersal is prevalent among contiguous amphibian populations using formal movement estimators. In contrast, if dispersal is naturally low in amphibians, fragmentation can be disregarded as a cause of amphibian declines and conservation efforts can be focused elsewhere. We examined dispersal rates in Columbia spotted frogs (Rana luteiventris) using capture– recapture analysis …

Population Structure Of Columbia Spotted Frogs (Rana Luteiventris) Is Strongly Affected By The Landscape, W. Chris Funk, Michael S. Blouin, Paul Stephen Corn, Bryce A. Maxell, David S. Pilliod, Stephen Amish, Fred W. Allendorf

United States Geological Survey: Staff Publications

Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing …