Physical Sciences and Mathematics Commons^™

Mylanodon Rosei, A New Metacheiromyid (Mammalia: Palaeanodonta) From The Late Tiffanian (Late Paleocene) Of Northwestern Wyoming, Ross Secord, Philip D. Gingerich, Jonathan I. Bloch

Department of Earth and Atmospheric Sciences: Faculty Publications

Mylanodon rosei is a new genus and species of late Paleocene metacheiromyid palaeanodont from a new late Tiffanian locality, Y2K Quarry, in the Clarks Fork Basin, Wyoming. The type is an adult dentary with P₄ and a molariform double-rooted M₁. This provides the first evidence that molariform teeth were retained in early Metacheiromyidae. A second specimen is a juvenile dentary with a partial P₃ and an unerupted P₄. This is the first juvenile dentition known for a Paleocene metacheiromyid. The new specimens enable determination of dental homologies. Reduction of teeth in early metacheiromyids took …

Loading Microcolumns For The Separation Of Analytes From A Sample In The Millisecond Time Scale, David S. Hage, William A. Clarke

David Hage Publications

The present invention generally relates to a microcolumn capable of separating an analyte from a sample in the millisecond time domain. The microcolumn is capable of such rapid separation by employing small column volumes that can tolerate medium to high flow rates. The invention also relates to a method of loading a microcolumn capable of separating an analyte from a sample in the millisecond time domain using plural injections of the packing material.

Search For Radiative B,-Hadron Decays In Pp̅ Collisions At √S=1.8 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We have performed a search for radiative b-hadron decays using events produced in pp̅ collisions at √s=1.8 TeV and collected by the Collider Detector at Fermilab. The decays we considered were B̅_d⁰→K^*0(→K^-π⁺) γ, B̅_s⁰→φ(→K⁺K^-) γ, Λ_b⁰→ Λ(→pπ^-) γ, and their charge conjugates. Two independent methods to identify photons from such decays were employed. In the first method, the photon was detected in the electromagnetic calorimeter. In the second method, the photon was identified …

Limits On Extra Dimensions And New Particle Production In The Exclusive Photon, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The exclusive γE/_T signal has a small standard model cross section and is thus a channel sensitive to new physics. This signature is predicted by models with a superlight gravitino or with large extra spatial dimensions. We search for such signals at the Collider Detector at Fermilab, using 87   pb^-1 of data at √s=1.8   TeV, and extract 95% C.L. limits on these processes. A limit of 221 GeV is set on the scale |F|^1/2 in supersymmetric models. For 4, 6, and 8 extra dimensions, model-dependent limits on the fundamental mass scale M_D of 0.55, 0.58, and …

Perturbative Calculation Of The Triply Differential Cross Section For Photo-Double-Ionization Of He, Andrei Y. Istomin, N. L. Manakov, Anthony F. Starace

Anthony F. Starace Publications

Single-photon, two-electron ionization of He is analyzed, taking into account electron correlation using lowest-order perturbation theory and including all individual electron angular momenta in the final two-electron continuum. Perturbative account of electron correlation in the final state, which describes the so-called TS-1 mechanism of double photoionization, combined with a variational account of electron screening, is found to provide results for the triply differential cross section at an excess energy of 20 eV that are in excellent agreement with both absolute experimental data and results of non-perturbative calculations, for all kinematics of the process in which the TS-1 mechanism is expected …

Search For The Production Of Single Sleptons Through R-Parity Violation In Pp̅ Collisions At √S = 1.8 Tev, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We report the first search for supersymmetric particles via s-channel production and decay of smuons or muon sneutrinos at hadronic colliders. The data for the two-muon and two-jets final states were collected by the D0 experiment and correspond to an integrated luminosity of 94 ± 5 pb^-1. Assuming that R parity is violated via the single coupling λ′₂₁₁, the number of candidate events is in agreement with expectation from the standard model. Exclusion contours are given in the (m₀; m_½) and (m_Χ̅,m_ν planes for λ′ …

Two-Photon Bremsstrahlung Processes In Atoms: Polarization Effects And Analytic Results For The Coulomb Potential, A. A. Krylovetskiĭ, N. L. Manakov, S. I. Marmo, Anthony F. Starace

Anthony F. Starace Publications

The partial wave analysis of two-photon free–free (bremsstrahlung) electron transition cross sections during scattering by a static potential U(r), as well as by an atom with a nonzero angular momentum, is carried out. The dipole interaction with radiation is taken into account in the second order of perturbation theory for the general case of elliptic polarization of photons. The polarization and angular dependences of the twophoton potential scattering amplitude is presented as a combination of the scalar product of electron momenta and photon polarization vectors and five atomic parameters containing Legendre polynomials of the scattering angle as …

Search For Minimal Supergravity In Single-Electron Events With Jets And Large Missing Transverse Energy In Pp̅ Collisions At √S =1.8 Tev, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We describe a search for evidence of minimal supergravity (MSUGRA) in 92.7 pb^-1 of data collected with the DØ detector at the Fermilab Tevatron pp̅ collider at√s =1.8 TeV. Events with a single electron, four or more jets, and large missing transverse energy were used in this search. The major backgrounds are from W +jets, misidentified multijet, tt̅, and WW production. We observe no excess above the expected number of background events in our data. A new limit in terms of MSUGRA model parameters is obtained.

Lake-Catchment Interactions With Climate In The Low Arctic Of Southern West Greenland, N. John Anderson, Sherilyn C. Fritz, Christopher E. Gibson, Bent Hasholt, Melanie J. Leng

Department of Earth and Atmospheric Sciences: Faculty Publications

Arctic hydrology plays a central role in the earth’s heat balance and ocean circulation (Vörösmarty et al. 2001). Future changes associated with human influence on the climate system are also predicted to cause major changes in the energy and hydrologic mass balance of Arctic catchments. Climate change will likely affect permafrost and snowmelt, which dominate Arctic hydrology and control the chemistry of surface runoff (and hence streams and lakes) as water percolates through the active layer. However, the controls and dynamic impact of snowmelt are poorly understood, because this critical timeframe is often missed by sampling programs. In the Søndre …

Blackbirds And Corn In Ohio, Richard A. Dolbeer

USDA Wildlife Services: Staff Publications

Damage to corn by blackbirds (Icteridae) has been an economic problem throughout historical times in North America. Ohio, with the highest nesting season population density of red-winged blackbirds (Agelaius phoeniceus) in North America and large acreages of corn, has been a key State in this conflict. Surveys of damage from 1968 to 1979 revealed that blackbirds annually destroyed less than 1% of the corn crops in Ohio, a 4- to 6-million dollar loss at 1979 prices. This total dollar loss is somewhat misleading because of the uneven distribution of damage among fields. Over 97% of the cornfields in Ohio receive …

Evaluation Of Lasers To Disperse American Crows, Corvus Brachyrhynchos, From Urban Night Roosts, W.P. Gorenzel, B. F. Blackwell, G.D. Simmons, T.P. Salmon, R.A. Dolbeer

USDA Wildlife Services: Staff Publications

American crows (Corvus brachyrhynchos) have a long history of causing agricultural damage in North America. Shooting and bombing at crow night roosts have been employed to reduce such damage. Most roosts were located in rural locations, but in the latter half of the 1900s crows began to roost in urban locations. Urban crow roosts are presently a nationwide problem in the United States. Thousands of crows at a roost create problems for businesses and residents. Improved control techniques are needed. Lasers have been used in Europe to scare and disperse birds but the technique has only recently received formal testing. …

Provenance Of Sand In Periglacial Sand Wedges And Sheet Sand, Northeastern Nebraska, Usa, William J. Wayne

Department of Earth and Atmospheric Sciences: Faculty Publications

Sand-wedge polygons on upland surfaces beneath thin loess in northeastern Nebraska record existence of permafrost around the margin of the Wisconsinan glacier at its maximum advance. Strong unidirectional wind not only kept the upland surfaces free of snow, allowing frost to penetrate deeply and thermal contraction cracks to develop, but also dessicated the surface material so that frost action and sublimation of pore ice could loosen surface material. The strong NW-SE winds deflated soils from upland surfaces, made ventifacts of the cobbles in the lag that remained and created fields of yardangs oriented NW-SE. Sand derived from the soils and …

Analysis Of Integrated Farming Systems In Eastern Nebraska, Lori A. Hoagland

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

Agroecosystems in the U.S. are beset with social, ecological and environmental problems as large industrial farming methods are edging out small family-sized farms and replacing ecological services provided by biodiversity with synthetic inputs and practices. While many of the benefits of smaller diversified or integrated farming systems are well known, farm producers need a concrete model that shows how integration is possible and with what crops. The objective of this study was to investigate some of these supplemental farm activities, and identify and evaluate whether they were compatible given the time and resource constraints of a typical eastern Nebraska farm. …

The Prairie Naturalist Volume 34, No. 3/4 September/December 2002

The Prairie Naturalist

SEASONAL FOOD HABITS OF COYOTES IN NORTHEASTERN KANSAS ▪ J. F. Kamler, P. S. Gipson, and C. C. Perchellet

SELECTION OF NESTING HABITAT BY SHARP-TAILED GROUSE IN THE NEBRASKA SANDHILLS ▪ B. L. Prose, B. S. Cade, and D. Hein

PATTERNS OF REPRODUCTION FOR WESTERN HARVEST MICE IN NORTH-CENTRAL KANSAS ▪ J. R. Goheen, G. A. Kaufman, and D. W. Kaufman

THE IMPACT OF RECREATIONAL TRAILS AND GRAZING ON SMALL MAMMALS IN THE COLORADO PIEDMONT ▪ C. A. Meaney, A. K. Ruggles, N. W. Clippinger, and B. C. Lubow

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA 2001 ▪ R. N. Randall …

Water Current, Volume 34, No. 6. December 2002

Water Current Newsletter

• UNL Aquaculturist Sees Fish Farming Niche in Empty Hog Barns by Steve Ress

• From the Director

• Meet the Faculty

• The Army Corps’ Missouri River Mission by Brig. Gen. David A. Fastabend

• Water News Briefs

Effects Of Germanium On The Electronic Transport Mechanism In Co20 (Cu-XGeX)80 Nanogranular Ribbons, J. He, Z. D. Zhang, J. Ping Liu, David J. Sellmyer

David Sellmyer Publications

The dependency of giant magnetoresistance (GMR) on the nonmagnetic matrix in nanogranular Co²⁰ (Cu^1-xGe^x)⁸⁰ ribbons was studied. When the matrix Cu is substituted with semiconductor Ge, the magnetoresistance transitioned from negative to positive at low temperatures. The positive GMR effect is closely related to the quantity of Co/Co³Ge²/Co junctionlike configurations. This result provides evidence for the competition between two types of electronic transport mechanisms in the magnetic granular ribbons: (i) electronic spin-dependent scattering, inducing a negative magnetoresistance and (ii) Coulomb blockade of the electronic tunneling, inducing a positive magnetoresistance.

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

Peter Dowben 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.

The Role Of Climate In Modern Water Planning And Related Decisions: Nebraska Case Study, Donna L. Woudenberg

Open Access Master's Theses (through 2010)

Climate and weather play an integral role in the planning and decision-making processes for those involved in agricultural and natural resource fields. This project was conducted to determine whether climate and weather data are being efficiently and effectively used in these processes.

A survey was mailed to those who work in water-related fields in Nebraska and post-survey interviews were conducted to obtain greater detail. Survey results were analyzed in the following three ways: as a whole; stratified by respondent’s agency; and stratified by the educational background of respondents. It was found that climate and weather data are more likely to …

Coexistence Of Ferromagnetic And Glassy States In Mechanically Milled Gdal2, C. Stark, P. M. Shand, T. M. Pekarek, D. Williams, R. Brown, Lanping Yue, Diandra Leslie-Pelecky

Diandra Leslie-Pelecky Publications

Measurements of DC susceptibility, AC susceptibility, and AC susceptibility with an applied DC bias field were performed on mechanically milled GdAl₂. A paramagnetic phase exists above a temperature T ≈ 140 K. However, there are significant deviations from the Curie-Weiss Law in this temperature regime, suggesting multiple magnetic components. Fits to the high temperature data show that two Curie-Weiss terms represent the data quite well. Below 140 K one of these magnetic components becomes ferromagnetic as indicated by a shoulder in the AC susceptibility and DC susceptibility data. This ferromagnetic component is suppressed by the application of sufficiently …

Crab Louse Infestation In Pre-Columbian America, F. M. Rick, G. C. Rocha, K. Dittmar, C. E. A. Coimbra Jr., Karl J. Reinhard, F. Bouchet, L. F. Ferreira, A. Araújo

School of Natural Resources: Faculty Publications

Until now, Pthirus pubis infestation in ancient human populations had only been recorded in the Old World. We found crab lice on South American mummified bodies from the Atacama Desert region. Crab louse eggs were found attached to the pubic hairs of a 2,000-yr-old Chilean mummy. Well-preserved adults were found in sediment and clothing from a Peruvian mummy dated 1,000 yr ago. Paleoparasitological evidence expands the knowledge of the distribution of this ectoparasite in ancient populations. As with many other parasites, pubic lice recorded in Andean populations show the antiquity of this parasite in the New World. It is likely …

Cross Section For Forward J/Ψ Production In Pp̅ Collisions At √S=1.8 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The inclusive cross section for J/ψ production times the branching ratio B(J/ψ→μ⁺μ^-) has been measured in the forward pseudorapidity region: B×dσ[p̅+p→J/ψ(p_T>10 GeV/c,2.1<|η|<2.6)+X]/dη=192±9(stat)±29(syst) pb. The results are based on 74.1±5.2 pb^-1 of data collected by the CDF Collaboration at the Fermilab Tevatron Collider. The measurements extend earlier measurements of the D0 Collaboration to higher p_T^J/ψ. In the kinematic range where the experiments partially overlap, these data are in good agreement with previous measurements.

Heterojunction Diode Fabrication From Polyaniline And A Ferroelectric Polymer, B Xu, Y. Ovchenkov, Mengjun Bai, A. N. Caruso, A.V. Sorokin, Stephen Ducharme, Bermard Doudin, Peter A. Dowben

Peter Dowben Publications

We have fabricated a p – n heterojunction diode by vapor depositing a thin film of polyaniline on top of the crystalline copolymer: poly(vinylidene fluoride with trifluoroethylene). The formation of a diode is expected from the band offsets of the two polymers near the Fermi level. The interface between the two components was investigated, and an abrupt interface was found that is very different from the inorganic analog.

Monte Carlo Simulation Of Vapor–Liquid Binodal Of Water, S. Yoo, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Among many popular potential models of water, the nonpolarizable four-site TIP4P potential is one of the more widely used. Recently, two new potential models of water on the basis of the TIP4P potential have been developed. One is the four-site Dang–Chang polarizable potential and another is the five-site TIP5P potential. The former is designed to describe not only bulk and interfacial properties of liquid water but also microclusters of water. The nonpolarizable TIP5P potential is the latest version in the TIP series from the Jorgensen group. Compared with the TIP4P potential, for example, the TIP5P potential gives a much improved …

A Proof-Of-Principle Experiment Of Optical Injection Of Electrons In Laser-Driven Plasma Waves, N. Saleh, P. Zhang, Shouyuan Chen, Z.-M. Sheng, Anatoly Maksimchuk, V. Yanovsky, Donald P. Umstadter

Donald Umstadter Publications

We report on a proof-of-principle experiment that demonstrates, for the first time, the feasibility of optically injecting electrons into laser-driven plasma waves, first proposed by [D. Umstadter, J.-K. Kim, and E. Dodd, Phys. Rev. Lett. 76, 2073 (1996)l. Using a Table-Top-Tera Watt laser system (I ~5x10¹⁸ W/cm², λ = 1 μm, τ = 400 fs), whose output beam is split by 1:4 ratio into a pump and injection beams, respectively, spatial (within 10 μm) and temporal (within 400 fs) overlap of the two beams were achieved by intersecting them orthogonally in an under-dense (~ 4x10¹⁹ cm …

Study Of Energetic Ion Generation From High-Intensity-Laser Dense-Plasma Interactions, K. Flippo, Anatoly Maksimchuk, Sudeep Banerjee, K. Nash, V. Wong, T. Lin, K. Nemoto, V. Yu. Bychenkov, Y. Sentoku, G. Mourou, Donald P. Umstadter

Donald Umstadter Publications

We report on the characteristics of an ultrafast-laser driven proton beam from thinfilm targets. The difference in proton beam profiles, beam energies, and laser induced back ablation plumes between a dielectric (Mylar) and a conductor (aluminum) are discussed. Evidence for front-side acceleration and a method for beam manipulation are also presented.

Developments In Relativistic Nonlinear Optics, Donald P. Umstadter, Sudeep Banerjee, Shouyuan Chen, E. Dodd, K. Flippo, Anatoly Maksimchuk, N. Saleh, A. Valenzuela, P. Zhang

Donald Umstadter Publications

We report recent results of experiments and simulations in the regime of peak laser intensities above 10¹⁹ W/cm², including the following topics: (1) electron and proton acceleration to energies in excess of 10 MeV in well collimated beams; (2) use of laser chirp to control the growth of plasma waves and acceleration of electrons by the Raman instability; (3) all optical injection and acceleration of electrons; (4) relativistic self-focusing by means of the mutual index of refraction of two overlapping laser pulses; (5) creation of a radioisotope by the reaction ¹⁰B(d,n)¹¹C; (6) …

A Socioeconomic And Biological Evaluation Of Current And Hypothetical Crappie Regulations In Sardis Lake, Mississippi: An Integrated Approach, Brian Dorr, Ian A. Munn, Keith O. Meals

USDA Wildlife Services: Staff Publications

We conducted a socioeconomic survey and review of existing biological data in an integrated evaluation of current and hypothetical fishery regulations on crappies Pomoxis spp. in Sardis Lake, Mississippi. The objectives of this study were to (1) assess angler acceptance of current and hypothetical harvest restrictions, (2) determine the recreational value of the crappie fishery to its participants, (3) estimate possible changes in recreational value based on angler responses to hypothetical regulations, and (4) integrate the results of the socioeconomic surveys with existing biological information. Using the travel cost method, we estimated mean expenditures at US$29.48 and average consumer surplus …

Langmuir-Blodgett Films Of Polyethylene, A.V. Sorokin, Mengjun Bai, Stephen Ducharme, Matt Poulsen

Stephen Ducharme Publications

The possibility to obtain surface layers on water and prepare solid multilayer Langmuir–Blodgett films of medium-density polyethylene is shown. The polymer film on water is stable, demonstrates a reversible surface pressure-area isotherm up to 15 mN/m, and can be deposited onto a substrate using the Langmuir–Blodgett technique in a wide range of surface pressures. The thickness of a single deposited layer is 5.1 nm on average. The dielectric and optical constants of multilayer films are near their bulk values. The films exhibit high dielectric strength of at least 200 MV/m.

Field Evaluation Of Flight ControlTm To Reduce Blackbird Damage To Newly Planted Rice, John L. Cummings, Michael L. Avery, Owen Mathre, E. Allen Wilson, Darryl L. York, Richard M. Engeman, Patricia A. Pochop, James E. Davis Jr.

USDA Wildlife Services: Staff Publications

An effective, economic, and environmentally safe bird repellent is needed to reduce blackbird (Icterinae) depredations to newly planted rice. We evaluated Flight Control^TM, a 50% anthraquinone product, as a seed treatment for newly planted rice. We treated rice seed with Flight Control at a 2% (g/g) concentration (1% active anthraquinone) the day of planting. This concentration reduced the number of blackbirds (P=0.0003) using treated fields and blackbird damage to rice seed (P=0.0124). The chemical concentration of anthraquinone on rice seed averaged 0.79% (SE=0.06%) at planting; 0.39% (SE= 0.04%) at day I, 0.34% (SE=0.05%) at …

Effect Of An Electric Field On The Surface Tension Of A Dipolar-Quadrupolar Fluid And Its Implication For Sign Preference In Droplet Nucleation, V.B. Warshavsky, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The effect of a uniform electric field on interfacial properties of dipolar-quadrupolar fluids is investigated by using the density-functional theory. As in the case of purely dipolar fluids the (thermodynamic) surface tension is always altered by the external field, regardless of the direction of the field. However, unlike the purely dipolar fluids, for two given external fields with the same strength but exactly opposite direction the magnitude of variation in the surface tension is different. This apparent symmetry breaking by reversing the field direction suggests a new molecular mechanism to explain the phenomenon of sign preference in droplet formation on …