Physical Sciences and Mathematics Commons^™

Seasonal Migration Of Columbia Spotted Frogs (Rana Luteiventris) Among Complementary Resources In A High Mountain Basin, David S. Pilliod, Charles R. Peterson, Peter I. Ritson

United States Geological Survey: Staff Publications

Information on how animals partition their activities and travel among complementary resources, such as breeding or overwintering habitats, is needed for species conservation. In a mountain basin at 2500 m elevation in central Idaho, we studied the habitat use and movement patterns of 736 marked and 87 radio-tagged Columbia spotted frogs (Rana luteiventris) from 1995 to 1998. The goals of this study were to (i) identify and characterize R. luteiventris breeding, summer foraging, and overwintering habitats, (ii) describe the movement patterns of juvenile, male, and female R. luteiventris among these resources, and (iii …

Quantification Of Plasma And Egg 4,4′ Dinitrocarbanilide (Dnc) Residues For The Efficient Development Of A Nicarbazin-Based Contraceptive For Pest Waterfowl, John J. Johnston, Walter M. Britton, Alexander Macdonald, Thomas M. Primus, Margaret J. Goodall, Christi A. Yoder, Lowell A. Miller, Kathleen A. Fagerstone

USDA Wildlife Services: Staff Publications

Urbanization and associated landscaping has increased the abundance of year-round habitat for waterfowl, resulting in vegetation damage, loss of recreational activities, air transportation mishaps and health hazards. As part of a research program to develop socially acceptable techniques for management of pest bird populations, we are evaluating nicarbazin as a contraceptive in pest and surrogate avian species. As reproductive studies with Canada Geese (Branta canadensis) are tedious due to the difficulty of conducting controlled field studies and/or breeding geese in captivity, we evaluated the effects of oral nicarbazin administration on the production and hatchability of chicken studies are …

Search For Gluinos And Squarks Using Like-Sign Dileptons In Pp̅ Collisions At √S= 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present results of the first search for like-sign dilepton (e^±e^{±, e± μ±, μ± μ±) events associated with multijets and large missing energy using 106 pb-1 of data in pp̅ collisions at √s= 1.8 TeV collected during 1992–1995 by the CDF experiment. Finding no events that pass our selection, we examine pair production of gluinos (g̃) and squarks (q̃) in a constrained framework of the minimal supersymmetric standard model. At tanβ =2 and μ = -800 GeV/c2, we set 95% confidence …}

Ratio Of Isolated Photon Cross Sections In Pp̅ Collisions At √S = 630 And 1800 Gev, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

The inclusive cross section for production of isolated photons has been measured in pp̅ collisions at √s = 630 GeV with the D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy (E_T) range from 7–49 GeV and have pseudorapidity∣η∣ < 2.5. This measurement is combined with the previous D0 result at √s = 1800 GeV to form a ratio of the cross sections. Comparison of next-to-leading-order QCD with the measured cross section at 630 GeV and the ratio of cross sections show satisfactory agreement in most of the E_T range.

Dilution-Induced Enhancement Of The Blocking Temperature In Exchange-Bias Heterosystems, Xi Chen, Christian Binek, A. Hochstrat, Wolfgang Kleemann

Christian Binek Publications

The temperature dependence of the exchange bias field is investigated by superconducting quantum interference device magnetometry in Fe_1-xZn_xF2(110)/Fe14 nm/Ag35 nm, x=0.4. Its blocking temperature exhibits a significant enhancement with respect to the global ordering temperature T_N=46.9 K, of the bulk antiferromagnet Fe_0.6Zn_0.4F₂. The enhancement is attributed to fluctuations of the diamagnetic dilution which creates clusters on all length scales having a Zn dilution of 0<~x<~1. While the infinite clusters give rise to the well-known Griffiths phase, finite clusters also provoke a local enhancement of the exchange bias. The temperature dependence of the integral exchange bias effect is modeled by averaging all local contributions of the antiferromagnetic surface magnetization which exhibit a surface critical behavior.

Observation Of Diffractive J/Ψ Production At The Fermilab Tevatron, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report the first observation of diffractive J/ψ(→μ⁺μ^-) production in p̅p collisions at √s= 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p_{T,/sub> ^μ> 2 GeV/c within the pseudorapidity region |η| J/ψ production rates is found to be RJ/ψ=[1.45 ± 0.25]%. The ratio RJ/ψ(x) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio Rjj(x) for diffractive dijet production, we extract a value of 0.59 …}

Search For Quark-Lepton Compositeness And A Heavy W′ Boson Using The Eν Channel In Pp̅ Collisions At √S = 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present searches for quark-lepton compositeness and a heavy W′ boson at high electron-neutrino transverse mass. We use ~110 pb^-1 of data collected in pp̅ collisions at √s= 1.8 TeV by the CDF Collaboration during 1992–1995. The data are consistent with standard model expectations. Limits are set on the quark-lepton compositeness scale Λ, the ratio of partial cross sections σ (W′ → eν)/ σ (W → eν), and the mass of a W′ boson with standard model couplings. We exclude Λ< 2.81 TeV and a W′ boson with mass below 754 GeV/c² at the 95% …

Search For New Physics Using Quaero: A General Interface To D0 Event Data, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We describe QUAERO, a method that (i) enables the automatic optimization of searches for physics beyond the standard model, and (ii) provides a mechanism for making high energy collider data generally available. We apply QUAERO to searches for standard model WW, ZZ , and tt̅ production, to searches for these objects produced through a new heavy resonance, and to the first direct search for W′→ WZ. Through this interface, we make three data sets collected by the D0 experiment at √s =1.8 TeV publicly available.

Effects Of Binary Combinations Of Herbicides On Freshwater Algae, Jill K. Taylor

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

No abstract provided.

The Biosynthetic Gene Cluster For The Anticancer Drug Bleomycin From Streptomyces Verticillus Atcc15003 As A Model For Hybrid Peptide–Polyketide Natural Product Biosynthesis, B. Shen, Liangcheng Du, C. Sanchez, D. J. Edwards, M. Chen, J. M. Murrell

Liangcheng Du Publications

The hybrid peptide–polyketide backbone of bleomycin (BLM) is assembled by the BLM megasynthetase that consists of both nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) modules. BlmIX/BlmVIII/BlmVII constitute a natural hybrid NRPS/PKS/NRPS system, serving as a model for both hybrid NRPS/PKS and PKS/NRPS systems. Sequence analysis and functional comparison of domains and modules of BlmIX/BlmVIII/BlmVII with those of nonhybrid NRPS and PKS systems suggest that (1) the same catalytic sites appear to be conserved in both hybrid NRPS–PKS and nonhybrid NRPS or PKS systems, with the exception of the KS domains in the hybrid NRPS/PKS systems that are unique; (2) …

The Prairie Naturalist Volume 33, No.4 December 2001

The Prairie Naturalist

SPECIES, SEASON, AND DENSITY OF BURIED SEEDS SURVIVING FOX SQUIRREL DEPREDATION ▪ C. C. Smith, and J. M. Briggs

RELATI0NSHIP OF HYDROLOGICAL CONDITIONS AND POPULATlONS OF BREEDING PIPING PLOVERS ▪ D. S. Licht,

DEMODICOSIS IN A WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) IN SOUTH DAKOTA ▪ C. N. Jacques, J. A Jenks. M. B. Hildreth. R. J. Schauer, and D. D. Johnson

SURVEYS OF CALLING AMPHIBIANS IN NORTH DAKOTA ▪ D. H. Johnson, and R. D. Batie

EFFECTS OF HUMAN PRESENCE ON VOCALIZATIONS OF GRASSLAND BIRDS IN KANSAS ▪ S. L Bye, R. J. Robel, and K. E. Kemp

Reviewers 2001

Author …

Water Current, Volume 33, No. 6. December 2001

Water Current Newsletter

• “Daisy Well System” Promising Way for Small Communities to Fight Nitrates by Steve Ress

• From the Director

• Meet the Faculty

• Water and the NRCS…All Encompassing Topics by Steve Chick

• Variety and Current Issues Punctuate Spring Water and Natural Resources Seminar by Steve Ress

• Integrated Water Management Options in the Nebraska Ground Water Management & Protection Act by J. David Aiken

• Arkansas Researchers Study Water Quality on Nebraska Tribal Lands by Ralph Davis and Shelley McGinnis

• Platte River Policy Preferences by Raymond J. Supalla

• Water News Briefs

Atomic And Electronic Structure Of Co/Srtio3/Co Tunnel Junctions, Ivan I. Oleinik, Evgeny Y. Tsymbal, David G. Pettifor

Evgeny Tsymbal Publications

First-principles density-functional calculations of the atomic and electronic structure of Co/SrTiO₃ /Co (001) magnetic tunnel junctions (MTJ’s) are performed. Different interface terminations are considered and the most stable structure with the TiO₂ termination is identified based on energetics of adhesion. The calculated electronic structure of the TiO₂-terminated MTJ shows an exchange coupling between the interface Co and Ti atoms mediated by oxygen. This coupling induces a magnetic moment of 0.25 µ_B on the interface Ti atom, which is aligned antiparallel to the magnetic moment of the Co layer. We argue that this might cause an …

A Case Study Of The 8 March 1999 Freezing Rain Event For North Platte, Nebraska, Shari Mutchler

United States Department of Commerce: Staff Publications

During the morning hours of 8 March 1999, freezing precipitation fell over portions of western Nebraska, including the communities of McCook, North Platte and Valentine between midnight and 10:00 A.M. CST. The freezing precipitation resulted in dangerous travel conditions, causing several automobile accidents, along with the delay and temporary closing of area public schools 8 March 1999. The freezing rain changed over to snow later the same morning.
A forecast for snow, rather than freezing precipitation, was issued by the local forecast office. The forecast issued was based predominately on numerical weather prediction guidance, and the observed temperature profile of …

Direct Imaging Of Human Swi/Snf-Remodeled Mono- And Polynucleosomes By Atomic Force Microscopy Employing Carbon Nanotube Tips, Gavin R. Schnitzler, Chin Li Cheung, Jason H. Hafner, Andrew J. Saurin, Robert E. Kingston, Charles M. Lieber

Barry Chin Li Cheung Publications

Chromatin-remodeling complexes alter chromatin structure to facilitate, or in some cases repress, gene expression. Recent studies have suggested two potential pathways by which such regulation might occur. In the first, the remodeling complex repositions nucleosomes along DNA to open or occlude regulatory sites. In the second, the remodeling complex creates an altered dimeric form of the nucleosome that has altered accessibility to transcription factors. The extent of translational repositioning, the structure of the remodeled dimer, and the presence of dimers on remodeled polynucleosomes have been difficult to gauge by biochemical assays. To address these questions, ultrahigh-resolution carbon nanotube tip atomic …

Electronic-Structure Modifications Induced By Surface Segregation In La0.65Pb0.35Mno3 Thin Films, C.N. Borca, B. Xu, T. Komesu, H.-K. Jeong, M.T. Liu, Sy_Hwang Liou, Shane Stadler, Y. Idzerda, Peter A. Dowben

Sy-Hwang Liou Publications

Using spin-polarized inverse photoemission and X-ray absorption spectroscopy techniques, we show that the electronic structure of La_0.65Pb_0.35MnO₃ thin films depends on the composition at the surface. With a gentle annealing procedure, the surface provides a maximum of 80% spin asymmetry at 0.5 eV above the Fermi level in spite of extensive Pb segregation. A heavily annealed (restructured) surface exhibits a reduced surface "ordering" temperature of 240 K (compared to the approximately 335 K bulk value) as well as a reduced spin asymmetry value of 40% at 0.5 eV above Fermi energy.

Comparison Of Instream Methods For Measuring Hydraulic Conductivity In Sandy Streambeds, Matthew K. Landon, David L. Rus, F. Edwin Harvey

School of Natural Resources: Faculty Publications

Streambed hydraulic conductivity (K) values were determined at seven stream transects in the Platte River Basin in Nebraska using different instream measurement techniques. Values were compared to determine the most appropriate technique(s) for use in sandy streambeds. Values of K determined from field falling- and constant-head permeameter tests analyzed using the Darcy equation decreased as permeameter diameter increased. Seepage meters coupled with hydraulic gradient measurements failed to yield K values in 40% of the trials. Consequently, Darcy permeameter and seepage meter tests were not preferred approaches. In the upper 0.25 m of the streambed, field falling- and constant-head permeameter tests …

Non-Target Impacts Of Strychnine Baiting To Reduce Pocket Gopher Populations On Forest Lands In The United States, Dale L. Nolte, Kimberly Wagner

USDA Wildlife Services: Staff Publications

Reforestation efforts are often severely hindered on sites that contain high populations of pocket gophers (Thmmysspp). Strychnine baiting is a technique used to suppress pocket gopher populations until seedlings are established. Strychnine bait is applied below ground in pocket gopher burrows, however, primary and secondary hazards remain a concern. A study to assess primary hazards indicated that some individual rodents died post strychnine baiting but there was not a long-term negative impact on non-target rodent populations. Possible secondary hazards reflect the potential for predators OT scavengers to encounter poisoned pocket gophers. Concerns that pocket gophers may surface before …

Interactions Of Ultrashort, Ultrahigh Intensity Laser Pulses With Underdense Plasmas, Xiaofang Wang, Wei Yu, Sterling Backus, Margaret Murnane, Henry Kapteyn, Donald P. Umstadter

Donald Umstadter Publications

The interactions of ultraintense laser pulses with underdense plasmas are studied in a new regime in which the longitudinal spatial extent of the pulse duration is close to both the laser focal spot size and the plasma wavelength.

Laser Acceleration Of Protons From Thin Film Targets, K. Flippo, Sudeep Banerjee, V. Yu. Bychenkov, S. Gu, Anatoly Maksimchuk, G. Mourou, K. Nemoto, Donald P. Umstadter

Donald Umstadter Publications

A collimated beam of fast protons, with energies as high as 10 MeV and total number of 10⁹, confined in a cone angle of 40°±10° has been observed when a 10 TW laser with frequencies either ω₀ (corresponding to 1 μm) or 2ω₀ was focused to an intensity of a few times 10¹⁸ W/cm² on the surface of a thin film target. The protons, which originate from impurities on the front side of the target, are accelerated over a region extending into the target and exit out the backside in a direction normal to …

Status Of The Lilac Experiment, N. Saleh, P. Han, C. Keppel, P. Gueye, V Yanovsky, Donald P. Umstadter

Donald Umstadter Publications

We present the status of the LILAC experiment [1], including results on the propagation of 30-fs duration laser pulses in plasmas of the requisite density, and measurements of the dark current [2]. We also discuss the status of a laser upgrade, an electron beam line and plans for the future.

Charged-Particle Multiplicity Pp̅ Collisions At √S = 1.8 Tev, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report on a measurement of the mean charged-particle multiplicity of jets in dijet events with dijet masses in the range 80-630 GeV/c², produced at the Tevatron in pp̅ collisions with √s= 1.8 TeV and recorded by the Collider Detector at Fermilab. The data are fit to perturbative-QCD calculations carried out in the framework of the modified leading log approximation and the hypothesis of local parton-hadron duality. The fit yields values for two parameters in that framework: the ratio of parton multiplicities in gluon and quark jets, r=N^g-jet _partons/N^q-jet _partons =1.7 ± …

Novel Field Sampling Procedure For The Determination Of Methiocarb Residues In Surface Waters From Rice Fields, Thomas M. Primus, Dennis J. Kohler, Mike Avery, Pat Bolich, M.O. Way, John J. Johnston

USDA Wildlife Services: Staff Publications

Methiocarb was extracted from surface water samples collected at experimental rice field sites in Louisiana and Texas. The sampling system consisted of a single-stage 90-mm Empore extraction disk unit equipped with a battery-powered vacuum pump. After extraction, the C-18 extraction disks were stored in an inert atmosphere at -10 °C and shipped overnight to the laboratory. The disks were extracted with methanol and the extracts analyzed by reversed-phase high-performance liquid chromatography with a methanol/water mobile phase. Methiocarb was detected by ultraviolet absorption at 223 nm and quantified with the use of calibration standards. Recoveries from control surface water samples fortified …

Magnetic Ordering In An Organic Polymer, Andrzej Rajca, Jirawat Wongsriratanakul, Suchada Rajca

Andrzej Rajca Publications

We describe preparation and magnetic properties of an organic p-conjugated polymer with very large magnetic moment and magnetic order at low temperatures. The polymer is designed with a large density of cross-links and alternating connectivity of radical modules with unequal spin quantum numbers (S), macrocyclic S = 2 and, cross-linking S = ½ modules, which permits large net S values for either ferromagnetic or antiferromagnetic exchange couplings between the modules. In the highly cross-linked polymer, an effective magnetic moment corresponding to an average S of about 5000 and slow reorientation of the magnetization by a small magnetic field …

Ac Susceptibility Studies Of Discontinuous Co80fe20al2o3 Multilayers, Christian Binek

Christian Binek Publications

Discontinuous metal–insulator multilayers [Co80Fe20(t)/Al2O3(3 nm)]10 are prepared by ion-beam sputtering and investigated by SQUID magnetometry and previous AC susceptometry. For 1.0less-than-or-equals, slanttless-than-or-equals, slant1.6 nm, two coexisting subsystems of dipolar coupled nanoparticles are encountered. While a spin-glass-like freezing particulate fraction dominates at t=1.0 nm, a percolating dipolar ferromagnetic fraction becomes increasingly important at higher nominal thickness of t.

Exchange Bias In Fef20-Copt Heterosystems With Perpendicular Anisotropy, Christian Binek

Christian Binek Publications

The previous exchange bias effect is measured in heterosystems with perpendicular anisotropy consisting of Co/Pt multilayers on top of the (0 0 1) face of a previous FeF2 single crystal. The resulting previous exchange field HE exhibits a strong dependence on temperature and the axial freezing field, HF. Within the framework of an Ising-type model, the HE vs. T as well as the HE vs. HF data are explained in terms of the microscopic spin structure at the interface.

Entropy Splitting For High Order Numerical Simulation Of Vortex Sound At Low Mach Numbers, Bernhard Müller, H. C. Yee

United States National Aeronautics and Space Administration: Publications

Several recent developments in efficient, stable, highly parallelizable high order non-dissipative spatial schemes with characteristic based filters that exhibit low dissipation for long time linear and nonlinear wave propagations are utilized for computational aeroacoustics (CAA). For stability consideration, the Euler equations are split into a conservative and a symmetric non-conservative portion. Due to the large disparity of acoustic and stagnation quantities in low Mach number aeroacoustics, the split Euler equations are formulated in perturbation form to minimize numerical cancellation errors. Spurious oscillations are suppressed by a characteristic-based filter. The method has been applied to accurately simulate the sound emitted by …

Monte Carlo Simulation Of Homogeneous Binary Vapor–Liquid Nucleation: Mutual Enhancement Of Nucleation In A Partially Miscible System, S. Yoo, K.J. Oh, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Gibbs free energy of ij-cluster formation ΔG_ij is obtained via the relation n_ij=Ne^{-ΔG_ij /k_BT}, where N is the number of molecules in the system, T is temperature, and kB is the Boltzmann constant. The saddle point on the free energy surface ΔG_ij versus i and j provides a measure of the activation barrier to nucleation ΔG *. A statistical mechanical formula of ΔG_ij is derived based on the physical-cluster theory of nucleation, and from which a molecular interpretation of ΔG_{ij …}

Differential Responses Of Coyotes To Novel Stimuli In Familiar And Unfamiliar Settings, Charles E. Harris, Frederick F. Knowlton

USDA Wildlife Services: Staff Publications

We studied behavioral responses of captive and wild coyotes (Canis latrans) toward novel objects and artificial scent stations to determine how they might respond to novel stimuli used in coyote management and research. When captive coyotes encountered novel stimuli in unfamiliar surroundings they showed little avoidance, while the same stimuli caused avoidance and neophobic reactions among coyotes when encountered in familiar surroundings. In the field phase of the study, radio-collared coyotes in southern Texas were intensively monitored in order to relate space-use patterns to the locations where these coyotes were exposed to artificial scent stations. Coyotes were more …

The Demographic Response Of Bank-Dwelling Beavers To Flow Regulation: A Comparison On The Green And Yampa Rivers, Stewart W. Breck, Kenneth R. Wilson, Douglas C. Anderson

USDA Wildlife Services: Staff Publications

We assessed the effects of flow regulation on the demography of beavers (Castor canadensis) by comparing the density, home-range size, and body size of bank-dwelling beavers on two sixth-order alluvial river systems, the flow-regulated Green River and the free-flowing Yampa River, from 1997 to 2000. Flow regulation on the Green River has altered fluvial geomorphic processes, influencing the availability of willow and cottonwood, which, in turn, has influenced the demography of beavers. Beaver density was higher on the Green River (0.5–0.6 colonies per kilometer of river) than on the Yampa River (0.35 colonies per kilometer of river). Adult …