Physical Sciences and Mathematics Commons^™

Method For Prevention Of Solid Dissolution Through Covalent Ligand Bonding, David A. Atwood

Chemistry Faculty Patents

Methods for preventing dissolution of solid substrates, such as metal leaching from coal or corrosion of metal surfaces, are provided.

To read the remainder of this abstract, please download this patent.

Presentation To Friends Of Red Rock Canyon February 8, 2005, Nancy Flagg

Presentations (PLI)

University engages in selected SNPLMA projects as determined by the four federal agencies, which are:

• Compatible with UNLV’s mission.
• Enhance education and research.
• Draw upon expertise of faculty, staff, and students.

Nonlinear Absorption, Scattering And Optical Limiting Studies Of Cds Nanoparticles, N. Venkatra, D. Narayana Rao, Murty Akundi

Faculty and Staff Publications

The nonlinear optical absorption, scattering and optical limiting properties of CdS nanoparticles dispersed in dimethylformamide (DMF) are investigated. The nanoparticles are synthesized using the standard chemical synthesis method with thioglycerol as the capping agent. The investigations are carried out at 532 nm in the ns regime. Strong two-photon absorption and nonlinear scattering are found to be responsible for good optical limiting characteristics in these nanoparticles.

How To Survive And Thrive In A Search Engine Culture, Gordon C. Tibbitts

Gordon C. Tibbitts III

A comparison of CrossRef Search and Google Scholar. It's essential to have a strategy when working with Google. Proprietary "vertical" search engines such as CrossRef will have a place even with the strength of an engine like Google Scholar (and Google search in general).

Complex Energy Shift And Background Phase Shift For Simulated Electron-Molecular Shape Resonances, Gordon A. Gallup

Gordon Gallup Publications

Feshbach-Fano resonance theory (FFRT) is used to determine the energy dependence of the complex energy shift function, consisting of the real energy shift and the resonance width, and the background phase shift for several simulated molecular shape resonances. Attention is paid to the way the choice of the quasibound state (QBS) function required in the FFRT affects these energy dependencies. An overlap criterion for choosing an optimal QBS function is proposed. Using our treatment on t-butylchloride, carbon tetrachloride, ethylene, and benzene, we give numerical results for specific cases of l = 1 through 4. We find that the real …

A Hybrid Lagrangian Variational Method For Bose–Einstein Condensates In Optical Lattices, Mark Edwards, Lisa M. Debeer, Mads Demenikov, Jacob Galbreath, T. Joseph Mahaney, Bryan Nelsen, Charles W. Clark

Department of Physics and Astronomy Faculty Publications

Solving the Gross–Pitaevskii (GP) equation describing a Bose–Einstein condensate (BEC) immersed in an optical lattice potential can be a numerically demanding task. We present a variational technique for providing fast, accurate solutions of the GP equation for systems where the external potential exhibits rapid variation along one spatial direction. Examples of such systems include a BEC subjected to a one-dimensional optical lattice or a Bragg pulse. This variational method is a hybrid form of the Lagrangian variational method for the GP equation in which a hybrid trial wavefunction assumes a Gaussian form in two coordinates while being totally unspecified in …

Developing A Genetic System For Functional Manipulations Of Fum1, A Polyketide Synthase Gene For The Biosynthesis Of Fumonisins In Fusarium Verticillioides, Fengan Yu, Xiangcheng Zhu, Liangcheng Du

Liangcheng Du Publications

Fumonisins are mycotoxins produced by Fusarium verticillioides, a filamentous fungus that is a widespread pathogen of corn. The biosynthesis of fumonisins is catalyzed by an iterative modular polyketide synthase (PKS). The study of the biosynthetic mechanism for these reduced fungal polyketides has been challenging due to the difficulties in detecting the intermediates with a linear carbon chain and manipulating the 7-domain PKS gene from the filamentous fungus. Here, we described the development of a genetic system for functionally manipulating the methyltransferase domain of FUM1 that is responsible for the assembly of a dimethylated 18-carbon chain. Using a two-stage screening strategy, …

Isotropy Of The Early Universe From Cmb Anisotropies, Evan P. Donoghue, John Donoghue

John Donoghue

The acoustic peak in the CMB power spectrum is sensitive to causal processes and cosmological parameters in the early universe up to the time of last scattering. We provide limits on correlated spatial variations of the peak height and peak position and interpret these as constraints on the spatial variation of the cosmological parameters (baryon density, cold dark matter density and cosmological constant as well as the amplitude and tilt of the original fluctuations). We utilize recent work of Hansen, Banday and Gorski (HBG) who have studied the spatial isotropy of the power spectrum as measured by WMAP by performing …

A Study Of Bright Southern Long Period Variables, Thomas Lebzelter, Kenneth H. Hinkle, Peter R. Wood, Richard R. Joyce, Francis C. Fekel

Information Systems and Engineering Management Research Publications

In this paper we present radial velocity curves of AGB variables that exhibit various kinds of anomalies: semiregular variables (SRVs) with typical mira periods, SRVs exceeding the mira 2.5 mag amplitude limit, miras with secondary maxima in their light curves, and a SRV with a long secondary period. The stars with reliable Hipparcos parallaxes from this and from previous studies are plotted in a -diagram. Our objects nicely follow the -relations determined for the LMC. This allows the pulsation mode to be identified. While all miras fall on the fundamental mode sequence, the SRVs fall on both the first overtone …

Generalized Ohm's Law In A 3-D Reconnection Experiment, C. D. Cothran, Matthew Joseph Landreman , '03, Michael R. Brown, W. H. Matthaeus

Physics & Astronomy Faculty Works

We report the measurement of non-ideal terms of the generalized Ohm's law at a reconnection site of a weakly collisional laboratory magnetohydrodynamic plasma. Results show that the Hall term dominates the measured terms; resistive and electron inertia terms are small. We suggest that electron pressure (not measured) supports the observed quasistatic reconnection rate, and that anomalous resistivity, while not ruled out, is not required to account for the results.

Measurement Of The BS0 Lifetime In The Exclusive Decay Channel BS0 → J/Ψφ, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

Using the exclusive decay B_s⁰ → J/ψ(μ⁺μ^-)Φ(K⁺K^-), we report the most precise single measurement of the B_s⁰ lifetime. The data sample corresponds to an integrated luminosity of approximately 220 pb^-1 collected with the D0 detector at the Fermilab Tevatron Collider in 2002–2004. We reconstruct 337 signal candidates, from which we extract the B_s⁰ lifetime, τ(B_s⁰) = 1.444_-0.090^+0.098(stat) ± 0.020(sys) ps. We also report a measurement for the lifetime of the B⁰ meson using the exclusive …

Search For Supersymmetry With Gauge-Mediated Breaking In Diphoton Events At D0, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We report the results of a search for supersymmetry (SUSY) with gauge-mediated breaking in the missing transverse energy distribution of inclusive diphoton events using 263 pb^-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider in 2002–2004. No excess is observed above the background expected from standard model processes, and lower limits on the masses of the lightest neutralino and chargino of about 108 and 195 GeV, respectively, are set at the 95% confidence level. These are the most stringent limits to date for models with gauge-mediated SUSY breaking with a short-lived neutralino as the next-to-lightest …

Impact Of The Synthesis Process On Structure Properties For Afci Fuel Candidates, Thomas Hartmann, Kenneth Czerwinski

Fuels Campaign (TRP)

Transmutation work at Los Alamos National Laboratory is currently focused on mono-nitride ceramic fuel forms, and consists of closely coordinated “hot” actinide and “cold” inert and surrogate fuels work. Matrix and surrogate materials work involves three major components: (1) fuel matrix synthesis and fabrication, (2) fuel performance, and (3) fuel materials modeling. The synthesis and fabrication component supports basic material studies, as well as actinide fuel fabrication work through fuel fabrication process development. Fuel performance studies are examining the tolerance of nitride-type fuel to heavy irradiation damage. The fuel materials simulation work involves both atomistic and continuum scale modeling employing …

Measurement Of W Γ And Z Γ Production In Pp̅ Collisions At √S =1.96 Tev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The standard model predictions for W γ and Z γ production are tested using an integrated luminosity of 200 pb-1 of pp̅ collision data collected at the Collider Detector at Fermilab. The cross sections are measured by selecting leptonic decays of the W and Z bosons, and photons with transverse energy ET>7 GeV that are well separated from leptons. The production cross sections and kinematic distributions for the W γ and Zγ data are compared to SM predictions.

Comparison Of Three-Jet Events In Pp̅ Collisions At √S = 1.8 Tev To Predictions From A Next-To-Leading Order Qcd Calculation, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for pp̅ collisions at √s = 1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and may give some indication of the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466±3(stat.) …

Cystic Renal Neoplasia Following Conditional Inactivation Of Apc In Mouse Renal Tubular Epithelium, Chao Nan Qian, Jared Knol, Peter Igarashi, Fangming Lin

University Faculty Publications and Creative Works

Alterations in Wnt/β-catenin signaling have been linked to abnormal kidney development and tumorigenesis. To gain more insights into the effects of these alterations, we created mice carrying a conditional deletion of the Apc tumor suppressor gene specifically in the renal epithelium. As expected, the loss of Apc leads to increased levels of β-catenin protein in renal epithelium. Most of these mice die shortly after birth, and multiple kidney cysts were found upon histological examination. Only rarely did these animals survive to adulthood. Analysis of these adults revealed severely cystic kidneys associated with the presence of renal adenomas. Our results confirm …

Measurement Of The J/ Ψ Meson And B-Hadron Production Cross Sections In Pp̅ Collisions At √S =1960 Gev, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We present a new measurement of the inclusive and differential production cross sections of J/ψ mesons and b hadrons in proton-antiproton collisions at √s=1960 GeV. The data correspond to an integrated luminosity of 39.7 pb^-1l collected by the CDF run II detector. We find the integrated cross section for inclusive J/ψ production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y|-0.33^+0.36 (syst) µb. We separate the fraction of J/ψ events from the decay of the long-lived b hadrons using the lifetime distribution in all events with p_T( …

Performance Of Convolutional Interleavers With Different Spacing Parameters In Turbo Codes, Sina Vafi, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

This paper considers application of a convolutional interleaver and the issue of influence of the space parameter in the turbo code performance. Similarly to previously considered convolutional interleavers, the new interleavers are designed as block interleavers and their performance in different code structures is compared with the interleaver having higher periods and space value of 1. In each comparison, the number of inserted stuff bits at the end of each data block is considered to be of similar order. Finally, suitable modification to the new interleavers is proposed improving performance for the codes with lower number of stuff bits.

Forest Structure And Mortality In An Old-Growth Jeffrey Pine-Mixed Conifer Forest In North-Western Mexico, Scott L. Stephens, Samantha J. Gill

Natural Resources Management and Environmental Sciences

Over 10 million hectares of forests in the western United States are in need of restoration. Restoration targets benefit from quantitative descriptions but many old-growth definitions are qualitative. Quantification of live forest structure and mortality in Jeffrey pine-mixed conifer forests in the Sierra San Pedro Martir (SSPM), Mexico, was done to assist in the development of restoration goals and to increase our understanding of old-growth forests. Conifer forests in the SSPM have not experienced systematic fire suppression or harvesting making them unusual in western North America. Tree and soil data were collected from a systematic design of plots. High variability …

A Framework For Management Of Concurrent Xml Markup, Alex Dekhtyar, Ionut E. Iacob

Computer Science and Software Engineering

The problem of concurrent markup hierarchies in XML encodings of documents has attracted attention of a number of humanities researchers in recent years. The key problem with using concurrent hierarchies to encode documents is that markup in one hierarchy is not necessarily well-formed with respect to the markup in another hierarchy. Previously proposed solutions to this problem rely on the XML expertise of the editors and their ability to maintain correct DTDs for complex markup languages. In this paper, we approach the problem of maintenance of concurrent XML markup from the Computer Science perspective. We propose a framework that allows …

Variable Selection For 1d Regression Models, David J. Olive, Douglas M. Hawkins

Articles and Preprints

Variable selection, the search for j relevant predictor variables from a group of p candidates, is a standard problem in regression analysis. The class of 1D regression models is a broad class that includes generalized linear models. We show that existing variable selection algorithms, originally meant for multiple linear regression and based on ordinary least squares and Mallows’ C_p, can also be used for 1D models. Graphical aids for variable selection are also provided.

Obtaining The Drop Size Distribution, Alexander Kostinski, Raymond Shaw

Department of Physics Publications

his document is a supplement to “Fluctuations and Luck in Droplet Growth by Coalescence,” by Alexander B. Kostinski and RaymondA. Shaw (Bull. Amer. Meteor. Soc.,86, 235–244) • ©2005 American Meteorological Society

Fluctuations And Luck In Droplet Growth By Coalescence, Alexander Kostinski, Raymond Shaw

Department of Physics Publications

After the initial rapid growth by condensation, further growth of a cloud droplet is punctuated by coalescence events. Such a growth process is essentially stochastic. Yet, computational approaches to this problem dominate and transparent quantitative theory remains elusive. The stochastic coalescence problem is revisited and it is shown, via simple back-of-the-envelope results, that regardless of the initial size, the fastest one-in-a-million droplets, required for warm rain initiation, grow about 10 times faster than the average droplet. While approximate, the development presented herein is based on a realistic expression for the rate of coalescence. The results place a lower bound on …

Integrated Fisheries Management Report Western Rock Lobster Resource., Department Of Fisheries

Fisheries management papers

This report is the first in a series of Integrated Fisheries Management (IFM) reports required under the 2004 Government Policy on IFM. Under this policy, the Executive Director of Fisheries is required to approve a sustainability report for each fishery, which includes a clear statement on the harvest level. The sustainable harvest level is that total catch, or catch range, that is to be allocated among the various user groups identified for that particular fishery. These IFM reports will assist in the process of allocating explicit shares in the use of Western Australia’s fish resources. They do not establish the …

X-Ray Variability During The Quiescent State Of The Neutron Star X-Ray Transient In The Globular Cluster Ngc 6440, Edward M. Cackett, Rudy Wijnands, Craig O. Heinke, Peter D. Edmonds, Walter H. G. Lewin, David Pooley, Jonathan E. Grindlay, Peter G. Jonker, Jon M. Miller

Physics and Astronomy Faculty Research Publications

The globular cluster NGC 6440 is known to harbor a bright neutron star X-ray transient. We observed the globular cluster with Chandra on two occasions when the bright transient was in its quiescent state, in 2000 July and 2003 June (both observations were made nearly 2 yr after the end of their preceding outbursts). The quiescent spectrum during the first observation is well represented by a two-component model (a neutron star atmosphere model plus a power-law component that dominates at energies above 2 keV). During the second observation (which was roughly of equal duration to the first observation) we found …

Signal In Noise: Evaluating Reported Reproducibility Of Serum Proteomic Tests For Ovarian Cancer, Keith A. Baggerly, Jeffrey S. Morris, Sarah R. Edmonson, Kevin R. Coombes

Jeffrey S. Morris

Proteomic profi ling of serum initially appeared to be dramatically effective for diagnosis of early-stage ovarian cancer, but these results have proven diffi cult to reproduce. A recent publication reported good classifi cation in one dataset using results from training on a much earlier dataset, but the authors have since reported that they did not perform the analysis as described. We examined the reproducibility of the proteomic patterns across datasets in more detail. Our analysis reveals that the pattern that enabled successful classifi cation is biologically implausible and that the method, properly applied, does not classify the data accurately. We …

Thin – Film Piezoelectric Acoustic Sensor (Tfpas): Further Experimental Validation Of The Theory Of Resonance Sensitivity., L. M. Dorozhkin, G N. Dorozhkina, Et Al, Alexander G. Sabelnikov

Alexander G Sabelnikov

No abstract provided.

Reliability, Effect Size, And Responsiveness Of Health Status Measures In The Design Of Randomized And Cluster-Randomized Trials, Paula Diehr

Paula Diehr

BACKGROUND: New health status survey instruments are often described by their psychometric (measurement) properties, such as Validity, Reliability, Effect Size, and Responsiveness. For cluster-randomized trials, another important statistic is the Intraclass Correlation (ICC) for the instrument within clusters. Studies using better instruments can be performed with smaller sample sizes, but better instruments may be more expensive in terms of dollars, opportunity cost, or poorer data quality due to the response burden of longer instruments. METHODS: We defined the psychometric statistics in terms of a mathematical model, and examined the power of a two-sample test as a function of the test-retest …

Designs In Partially Controlled Studies: Messages From A Review, Fan Li, Constantine E. Frangakis

Johns Hopkins University, Dept. of Biostatistics Working Papers

The ability to evaluate effects of factors on outcomes is increasingly important for a class of studies that control some but not all of the factors. Although important advances have been made in methods of analysis for such partially controlled studies,work on designs for such studies has been relatively limited. To help understand why, we review main designs that have been used for such partially controlled studies. Based on the review, we give two complementary reasons that explain the limited work on such designs, and suggest a new direction in this area.

Importance Of Thermal Disorder On The Properties Of Alloys: Origin Of Paramagnetism And Structural Anomalies In Bcc-Based Fe1−Xalx, Andrei V. Smirnov, W. A. Shelton, Duane D. Johnson

Duane D. Johnson

Fe1−xAlx exhibits interesting magnetic and anomalous structural properties as a function of composition and sample processing conditions arising from thermal or off-stoichiometric chemical disorder, and, although well studied, these properties are not understood. In stoichiometric B2 FeAl, including the effects of partial long-range order, i.e., thermal antisites, we find the experimentally observed paramagnetic response with nonzero local moments, in contrast to past investigations that find either a ferromagnetic or nonmagnetic state, both inconsistent with experiment. Moreover, from this magnetochemical coupling, we are able to determine the origins of the observed lattice constant anomalies found in Fe1−xAlx for x≃0.25–0.5 under various …