Physical Sciences and Mathematics Commons^™

Hubble Space Telescope Imaging Spectrograph Observations Of The Hot White Dwarf In The Close Binary Feige 24, Stephane Vennes, Elisha F. Polomski, Thierry Lanz, John R. Thorstensen

Dartmouth Scholarship

We obtained and analyzed two Hubble Space Telescope Imaging Spectrograph spectra of the white dwarf in the DA plus dMe binary Feige 24. The spectra, obtained at orbital quadratures, provide new estimates of the white dwarf motion and gravitational redshift resulting in revised white dwarf parameters. An analysis of interstellar absorption lines reveals the presence of two clouds (+3.1 km s-1, +17.6 km s-1) in the line of sight toward Feige 24; one of these clouds (+17.6 km s-1) is identified with the "local cloud." A study of the Lyα H I and D I interstellar medium lines shows that …

Ely Disrict Managed Natural And Prescribed Fire Plan, United States Department Of The Interior, Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.

Photonuclear Physics: Laser Splits Atom, Donald Umstadter

Donald Umstadter Publications

Lasers have become ubiquitous, being used in everything from a bar-code reader to a compact disk player. Who would have thought that they might be used to split the atom? A few scientists proposed to do just that more that a decade ago. But accomplishing it in the laboratory had to await the maturity of new technology, which enabled the construction of the world's most powerful lasers at the Lawrence Livermore National Laboratory in the United States and at the Rutherford Appleton Laboratory in the United Kingdom. Now two independent research teams have used these lasers to split the uranium …

Dijet Production By Double Pomeron Exchange At The Fermilab Tevatron, T. Affolder, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report the first observation of dijet events with a double Pomeron exchange topology produced in p̅p collisions at √s= 1800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a large rapidity gap on the outgoing proton side. We present results on jet kinematics and production rates, compare them with corresponding results from single diffractive and inclusive dijet production, and test factorization.

A Discotic Disguised As A Smectic: A Hybrid Columnar Bragg Glass, Karl Saunders, Leo Radzihovsky, John Toner

Physics

We show that discotics, lying deep in the columnar phase, can exhibit an x-ray scattering pattern which mimics that of a somewhat unusual smectic liquid crystal. This exotic, new glassy phase of columnar liquid crystals, which we call a “hybrid columnar Bragg glass,” can be achieved by confining a columnar liquid crystal in an anisotropic random environment of, e.g., strained aerogel. Long-ranged orientational order in this phase makes single-domain x-ray scattering possible, from which a wealth of information could be extracted. We give detailed quantitative predictions for the scattering pattern in addition to exponents characterizing anomalous elasticity of the system.

Continuum Pumping Of [Fe Ii] In The Orion Nebula, E. M. Verner, D. A. Verner, J. A. Baldwin, Gary J. Ferland, P. G. Martin

Physics and Astronomy Faculty Publications

This paper presents detailed comparisons between numerical simulations of Fe II emission spectra and recent high-resolution and signal-to-noise spectra of the Orion Nebula. We have identified 40 [Fe II] lines in the spectrum, allowing extensive comparisons between theory and observations. The identifications are based on predictions of a realistic model of the Fe II atom, which includes the lowest 371 levels (all levels up to 11.6 eV). We investigate the dependence of the spectrum on electron density and on pumping by the stellar continuum. Orion is important because it provides a relatively simple environment in which to test complex simulations. …

Astrophysical Quantities Of Cepheid Variables Measured With The Navy Prototype Optical Interferometer, Tyler E. Nordgren, J. T. Armstrong, M. E. Germain, R. B. Hindsley, Arsen R. Hajian, Jeffrey J. Sudol, C. A. Hummel

Physics & Engineering Faculty Publications

No abstract provided.

Parallel Phylogenetic Inference, Mark J. Clement, David Mclaughlin, Quinn O. Snell, Michael Whiting

Faculty Publications

Recent advances in DNA sequencing technology have created large data sets upon which phylogenetic inference can be performed. However, current research is limited by the prohibitive time necessary to perform tree search on even a reasonably sized data set. Some parallel algorithms have been developed but the biological research community does not use them because they don’t trust the results from newly developed parallel software. This paper presents a new phylogenetic algorithm that allows existing, trusted phylogenetic software packages to be executed in parallel using the DOGMA parallel processing system. The results presented here indicate that data sets that currently …

Chemical And Biological Trends During Lake Evolution In Recently Deglaciated Terrain, Daniel R. Engstrom, Sherilyn C. Fritz, James E. Almendinger, Stephen Juggins

Department of Earth and Atmospheric Sciences: Faculty Publications

As newly formed landscapes evolve, physical and biological changes occur that are collectively known as primary succession. Although succession is a fundamental concept in ecology, it is poorly understood in the context of aquatic environments. The prevailing view is that lakes become more enriched in nutrients as they age, leading to increased biological production. Here we report the opposite pattern of lake development, observed from the water chemistry of lakes that formed at various times within the past 10,000 years during glacial retreat at Glacier Bay, Alaska. The lakes have grown more dilute and acidic with time, accumulated dissolved organic …

Control Of Intense Laser- Atom Processes With Strong Static Fields, Dejan B. Milosevic, Anthony F. Starace

Anthony F. Starace Publications

Atomic processes in the presence of intense fields continue to attract a great deal of attention [1-3]. Key goals of research in this area are to increase the intensities and frequencies of coherent light produced in these processes. In two recent works [4,5] we have demonstrated theoretically the possibility of controlling intense laser-atom interaction processes by employing strong, but experimentally feasible, static electric or magnetic fields. Thus, in Ref. [4] we demonstrated how a strong static electric field may induce a high-energy plateau for scattered x-ray photons in laser-assisted, x-ray-atom scattering in which the incident x-rays were assumed to have …

Magmatic Processes Operating During The Middle To Late Pliocene And Pleistocene Along The Transition Zone Near 43º North, Christy L. Lee

Dissertations and Theses

A geochemical and structural transition zone exists between the Cascades and Basin and Range provinces in Oregon. Geologic mapping in this area has allowed the definition of six volcanic rock sequences: 1) interfingered alkali-rich basaltic trachyandesite to trachydacite lava flows and low-alkali basaltic andesite lava flows, 2) HAOT lava flows, 3) basaltic andesite lava flows, 4) andesite lava flows and vent deposits with minor basaltic andesite lava flows, 5) HAB lava flows, and 6) interfingered basaltic andesite, andesite, and trachyandesite lava flows.

Geochemical models of sequence 1 alkali-rich rocks suggest the fractionation of the parent assemblage plag (An₅₅)+magn+ol±aug …

The Effectiveness Of The Asos, Mmts, Gill, And Crs Air Temperature Radiation Shields*, K. G. Hubbard, X. Lin, E.A. Walter-Shea

School of Natural Resources: Faculty Publications

Periodic upgrades of air temperature measurement systems in surface weather station networks cause data discontinuities. From a climatological viewpoint, it is necessary to evaluate the air temperature data discontinuities when air temperature radiation shields are upgraded. This study was undertaken to investigate the effectiveness of four common air temperature radiation shields including the Automated Surface Observing System (ASOS), the Maximum–Minimum Temperature System (MMTS), the Gill, and the Cotton Region Shelter (CRS) shields. The solar radiation shielding effectiveness for each shield under typical grass ground surface and different artificial surfaces (black, white, and aluminum) were investigated. The shield effectiveness was evaluated …

Angular Momentum Partitioning And Hexacontatetrapole Moments In Impulsively Excited Argon Ions, H. M. Al-Khateeb, B. G. Birdsey, Timothy J. Gay

Timothy J. Gay Publications

We have studied polarized electron collisions with Ar in which the target is simultaneously ionized and excited to form Ar⁺(3p⁴(¹D)4p) states. We measured the integrated Stokes parameters of the subsequent fluorescence emitted by the ²F_7/2, ²F_5/2, ²D_5/2, and ²P_3/2 states along the direction of electron polarization. The Rubin-Bederson hypothesis is shown to hold for the L and S multipoles of these states. The electric quadrupole and hexadecapole of the 1D core are derived. By recoupling these moments with …

Enantioselective Reversed-Phase And Non-Aqueous Capillary Electrochromatography Using A Teicoplanin Chiral Stationary Phase, Charlotte Karlsson, Håkan Wikström, Daniel W. Armstrong, Paul K. Owens

Chemistry Faculty Research & Creative Works

Enantiomeric separation of chiral pharmaceuticals is carried out in aqueous and non-aqueous packed capillary electrochromatography (CEC) using a teicoplanin chiral stationary phase (CSP). Capillaries were slurry packed with 5 μm 100-A porous silica particles modified with teicoplanin and initially evaluated using a non-aqueous polar organic mode system suitability test for the separation of metoprolol enantiomers (R(s)=2.3 and 53 000 plates m-1). A number of pharmaceutical drugs were subsequently screened with enantioselectivity obtained for 25 racemic solutes including examples of neutral, acidic and basic molecules such as coumachlor (R(s)=3.0 and 86 000 plates m-1) and alprenolol (R(s)=3.3 and 135 000 plates …

Evaluation Of The Macrocyclic Glycopeptide A-40,926 As A High-Performance Liquid Chromatographic Chiral Selector And Comparison With Teicoplanin Chiral Stationary Phase, Alain Berthod, Timothy Yu, John P. Kullman, Daniel W. Armstrong, Francesco Gasparrini, Ilaria D'Acquarica, Domenico Misiti, Angelo Carotti

Chemistry Faculty Research & Creative Works

A new macrocyclic antibiotic of the vancomycin family, referred to by its industrial designation as A-40,926, was bonded to 5 μm silica particles and utilized as a chiral stationary phase (CSP). Since A-40,926 is structurally related to teicoplanin, the A-40,926 CSP was compared to a commercially available teicoplanin CSP. A set of 28 chiral compounds, including amino-acids and related compounds, compounds with a ring containing the stereogenic centre, compounds bearing aromatic structures near their stereogenic centres and alcohols, was tested for enantioseparation on the two CSPs. The results are compared and discussed in terms of enantioselective Gibbs energy difference. The …

Colombia: The Political Psychology Of Fusarium Oxysporum, Ibpp Editor

International Bulletin of Political Psychology

This article presents a brief outline of caveats associated with the employment of fusarium oxysporum to eradicate coca and opium poppy production. These caveats are based on an analysis developed by Dr. Archie Dickey, an environmental biologist at Embry-Riddle Aeronautical University, Prescott, Arizona, USA.

Universal Quantum Limits On Single-Channel Information, Entropy, And Heat Flow, Miles Blencowe, Vincenzo Vitelli

Dartmouth Scholarship

We show that the recently discovered universal upper bound on the thermal conductance of a single channel comprising particles obeying arbitrary fractional statistics is in fact a consequence of a more general universal upper bound, involving the averaged entropy and energy currents of a single channel connecting heat reservoirs with arbitrary temperatures and chemical potentials. The latter upper bound in turn leads, via Holevo's theorem, to a universal (i.e., statistics independent) upper bound on the optimum capacity for classical information transmission down a single, wideband quantum channel.

Comparative Studies Of Dissociative Electron Attachment To Methyl Halides, R. S. Wilde, Gordon A. Gallup, Ilya I. Fabrikant

Gordon Gallup Publications

The dissociative electron attachment cross sections for the methyl halides vary in an enormous range from the virtually unmeasurable 10⁻²³ cm² for CH₃Cl at room temperature to 10⁻¹⁴ cm² for CH₃I. In this paper we supplement our previous studies by calculations of dissociative electron attachment to CH₃Br and compare results for all methyl halides studied so far. The rate as a function of temperature for CH₃Cl and CH₃Br exhibits an exponential dependence on 1/T (Arrhenius law) with the activation energy lower for CH₃Br. …

Sfde's As Dynamical Systems (Symposium 2000/2001, University Of Warwick), Salah-Eldin A. Mohammed

Miscellaneous (presentations, translations, interviews, etc)

No abstract provided.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 17, Number 3, November 2000, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Tabletop Accelerators Are Brighter And Faster, Phil Schewe, Ben Stein, Donald P. Umstadter

Donald Umstadter Publications

At last week's APS plasma physics meeting, Donald Umstadter of the University of Michigan's Center for Ultrafast Optical Science (734-764-2284, [email protected]) reported on advances at his lab and elsewhere in tabletop laser accelerators, devices that use light to accelerate beams of electrons and protons to energies of a million volts in distances of only microns. This acceleration rate or "gradient" is up to a thousand times larger than in conventional accelerators because the tabletop laser light can now exert pressures of gigabars, the highest ever achieved, and approaching the pressure of light near the Sun. Not only that, but Umstadter's …

Proceedings Of The Arkansas Water Resources Center Annual Conference: Environmental Hydrology, Kenneth F. Steele

Arkansas Water Resources Center Technical Reports

The papers and abstracts in these proceedings are the result of a joint conference of the Arkansas Water Resources Center (A WRC) with the SouthCentral Section of the Geological Society of America. The joint conference was a success with about 250 participants. A WRC sponsored two sessions on Environmental Hydrology and a short course titled "Hydrogeology and Geochemistry of Salt Water Contamination." The Environmental Hydrology presentations covered wide-ranging topics that reflect the diversity of the environmental settings across Arkansas. Topics ranged from salt water and critical ground water issues in the Delta to endangered species and interbasin ground-water recharge in …

Holography, A Covariant C Function, And The Geometry Of The Renormalization Group, Vatche Sahakian

All HMC Faculty Publications and Research

We propose a covariant geometrical expression for the c function for theories which admit dual gravitational descriptions. We state a c theorem with respect to this quantity and prove it. We apply the expression to a class of geometries, from domain walls in gauged supergravities, to extremal and near extremal Dp-branes, and the AdS Schwarzschild black hole. In all cases, we find agreement with expectations.

Paramagnetic Meissner Effect In Nb Disks, Petru S. Fodor, Lowell E. Wenger

Physics Faculty Publications

Further details of the zero-field-cooled-magnetization and field-cooled-magnetization results on Nb disks exhibiting the paramagnetic Meissner effect (PME) are described. These studies indicate that two well-defined temperatures can be associated with features in the magnetization results. The higher characteristic temperature Tu is correlated with appearance of the paramagnetic moment and is strongly dependent upon the process used in forming the disk-shaped geometry of these Nb samples. The lower temperature Tp is associated with the “intrinsic coupling” of the interior Nb platelets. These latest results are shown to be consistent with the flux compression model for the appearance of the PME.

The Computational Complexity Of N-K Fitness Functions, Alden H. Wright, Richard K. Thompson, Jian Zhang

Computer Science Faculty Publications

N-K fitness landscapes have been widely used as examples and test functions in the field of evolutionary computation. Thus, the computational complexity of these landscapes as optimization problems is of interest. We investigate the computational complexity of the problem of optimizing the N-K fitness functions and related fitness functions. We give an algorithm to optimize adjacent-model N-K fitness functions which is polynomial in N. We show that the decision problem corresponding to optimizing random-model N-K fitness functions is NP-complete for K > 1 and is polynomial for K = 1. If the restriction that the ith component function depends …

Geosciences Newsletter - 2000, Department Of Geosciences

Geological and Environmental Sciences News

Vol.1, No. 25

• Greetings All
• Faculty News
• Groundwater Education in Michigan News
• Graduate Student News
• Alumni News
• Advisory Council News

Report Of The Qcd Tools Working Group, R. K. Ellis, R. Field, S. Mrenna, Gregory R. Snow, C. Balazs, E. Boos, J. Campbell, R. Demina, J. Huston, C-Y. P. Ngan, A. Petrelli, I. Puljak, T. Sjostrand, J. Smith, D. Stuart, K. Sumorok

Gregory Snow Publications

We report on the activities of the “QCD Tools for heavy flavors and new physics searches” working group of the Run II Workshop on QCD and Weak Bosons. The contributions cover the topics of improved parton showering and comparisons of Monte Carlo programs and resummation calculations, recent developments in Pythia, the methodology of measuring backgrounds to new physics searches, variable flavor number schemes for heavy quark electro-production, the underlying event in hard scattering processes, and the Monte Carlo MCFM for NLO processes.

Numerical Simulations Of Steady And Pulsed Non-Adiabatic Magnetised Jets From Young Stars, Stephen O'Sullivan, Tom Ray

Articles

No abstract provided.

Transgenic Crops: An Environmental Assessment, David E. Ervin, Sandra S. Batie, Rick Welsh, Chantal L. Carpentier, Jacqueline I. Fern, Nessa J. Richman, Mary A. Schulz

Economics Faculty Publications and Presentations

The report focuses on the environmental impacts of transgenic crops, and covers biosafety regulations in the US and EU, intellectual property rights, and market and trade developments.

Crystallization And Preliminary X-Ray Diffraction Studies On The Dna-Binding Domain Of The Multidrug Transporter Activation Protein (Mtan) From Bacillus Subtilis, M. H. Godsey, N. N. Baranova, A. A. Neyfakh, R. G. Brennan

CUP Faculty Research

The N-terminal DNA-binding domain of the multidrug transporter activation protein (MtaN) was crystallized by the hanging-drop vapour-diffusion method using lithium chloride as a precipitant. The crystals are orthorhombic and belong to the space group I2₁2₁2₁, with unit-cell parameters a = 49.4, b = 67.8, c = 115.0 Å. Diffraction data have been collected at 100 K to 2.75 Å resolution at a synchrotron-radiation source.