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2003

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Articles 451 - 480 of 3876

Full-Text Articles in Physical Sciences and Mathematics

Fabrication Of Nonepitaxially Grown Double-Layered Fept:C/Feconi Thin Films For Perpendicular Recording, M.L. Yan, Xingzhong Li, L. Gao, Sy_Hwang Liou, David J. Sellmyer, R.J.M Van De Veerdonk, K.W. Wierman Oct 2003

Fabrication Of Nonepitaxially Grown Double-Layered Fept:C/Feconi Thin Films For Perpendicular Recording, M.L. Yan, Xingzhong Li, L. Gao, Sy_Hwang Liou, David J. Sellmyer, R.J.M Van De Veerdonk, K.W. Wierman

Sy-Hwang Liou Publications

A noneptaxially grown double-layered thin-film medium of nanocompsite FePt:C with a FeCoNi soft underlayer for high-density perpendicular magnetic recording was fabricated and investigated. Square-shaped perpendicular loops with a remanance ratio nearly equal to one and a coercivity as large as 8.5 kOe were obtained for this ordered FePt:C double-layered medium. The formation of the ordered L10 phase is confirmed by electron diffraction experiments. Transmission electron microscope observations reveal that FePt grains with a uniform size less than 5 nm are embedded in the C matrix and appear to be well isolated. Our results show that nonepitaxially grown (001) textured …

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Gravitational Radiation From Pulsating White Dwarfs, M. Benacquista, D. M. Sedrakian, M. V. Hairapetyan, K. M. Shahabasyan, A. A. Sadoyan Oct 2003

Gravitational Radiation From Pulsating White Dwarfs, M. Benacquista, D. M. Sedrakian, M. V. Hairapetyan, K. M. Shahabasyan, A. A. Sadoyan

Physics and Astronomy Faculty Publications and Presentations

Rotating white dwarfs undergoing quasi-radial oscillations can emit gravitational radiation in a frequency range from 0.1 to 0.3 Hz. Assuming that the energy source for the gravitational radiation comes from the oblateness of the white dwarf induced by the rotation, the strain amplitude is found to be ∼10-27 for a white dwarf at ∼50 pc. The Galactic population of these sources is estimated to be ∼107 and may produce a confusion-limited foreground for proposed advanced detectors in the frequency band between space-based and ground-based interferometers. Nearby oscillating white dwarfs may provide a clear enough signal to investigate white dwarf interiors …

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Controlling H- Detachment With Few-Cycle Pulses, S. X. Hu, Anthony F. Starace Oct 2003

Controlling H- Detachment With Few-Cycle Pulses, S. X. Hu, Anthony F. Starace

Department of Physics and Astronomy: Faculty Publications

We present a detailed analysis of short-pulse detachment processes using few-cycle pulses with the aim of demonstrating means for controlling such processes. We first generalize the standard Keldysh-type formalism for laser-target interactions (in which final-state interaction between the detached electron and the core is ignored) to include the possibility that the vector potential is nonzero at the end of the interaction between a short laser pulse and the target. With this formalism in hand, we examine the effects of half-cycle pulses (HCPs) on detachment of the prototypical negative ion H–, and show that detachment by pairs of oppositely-directed (i.e., "bidirectional") …

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Using The Intensity Modulation Index To Test Pulsar Radio Emission Models, Fredrick A. Jenet, Janusz Gil Oct 2003

Using The Intensity Modulation Index To Test Pulsar Radio Emission Models, Fredrick A. Jenet, Janusz Gil

Physics and Astronomy Faculty Publications and Presentations

This Letter explores the possibility of testing pulsar radio emission models by observing pulse-to-pulse intensity modulation. It is shown that a relationship between a pulsar's period, period derivative, and intensity modulation is a natural consequence of at least one theoretical model of radio pulsar emission. It is proposed that other models may also predict a similar correlation. The exact form of the relationship will depend on the model in question. Hence, observations of intensity modulation should be able to determine the validity of the various emission models. In an attempt to search for the predicted dependencies, the modulation properties of …

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Lie Analysis Of The Webster Horn Equation With Application To Audio Object Recognition, Tania M. Barrett, Ian S. Burnett, Jason Lukasiak Oct 2003

Lie Analysis Of The Webster Horn Equation With Application To Audio Object Recognition, Tania M. Barrett, Ian S. Burnett, Jason Lukasiak

Faculty of Informatics - Papers (Archive)

The Webster horn equation describes the pressure wave in a duct of slowly varying cross section. We discuss symmetry reductions and exact solutions of the Webster horn equation using the classical Lie method of infinitesimals. The particular case of the exponential horn is examined and a complete set of reductions and solutions is formulated. The generation of a complete set of solutions using Lie analysis produces a set of group transformations. Particular attention is given to a new solution found, which contains an exponentially decaying Bessel function. The use of these group transformations as a tool for audio object recognition …

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Liberating The Inflaton From Primordial Spectrum Constraints, Christian Armendariz-Picon Oct 2003

Liberating The Inflaton From Primordial Spectrum Constraints, Christian Armendariz-Picon

Physics - All Scholarship

I discuss a mechanism that renders the spectral index of the primordial spectrum and the inflationary stage independent of each other. If a scalar field acquires an appropriate time-dependent mass, it is possible to generate an adiabatic, Gaussian scale invariant spectrum of density perturbations during any stage of inflation. As an illustration, I present a simple model where the time-dependent mass arises from the coupling of the inflaton to a second scalar. The mechanism I propose might help to implement a successful inflationary scenario in particle physics theories that do not yield slow-roll potentials.

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Quantum Corrections To The Schwarzschild And Kerr Metrics, N. E. J. Bjerrum-Bohr, John Donoghue, Barry R. Holstein Oct 2003

Quantum Corrections To The Schwarzschild And Kerr Metrics, N. E. J. Bjerrum-Bohr, John Donoghue, Barry R. Holstein

John Donoghue

We examine the corrections to the lowest order gravitational interactions of massive particles arising from gravitational radiative corrections. We show how the masslessness of the graviton and the gravitational selfinteractions imply the presence of nonanalytic pieces ;A2q2,;q2ln2q2, etc., in the form factors of the energy-momentum tensor and that these correspond to long range modifications of the metric tensor gmn of the form G2m2/r2,G2m\/r3, etc. The former coincide with well known solutions from classical general relativity, while the latter represent new quantum mechanical effects, whose strength and form is necessitated by the low energy quantum nature of the general relativity. We …

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Web Agents For Requirements Consistency Management, Z. Chen, Aditya K. Ghose Oct 2003

Web Agents For Requirements Consistency Management, Z. Chen, Aditya K. Ghose

Faculty of Informatics - Papers (Archive)

Inconsistency handling is an aspect of requirements engineering that has attracted considerable research attention. We explore novel ways to applying semantic Web technologies to this problem, in the context of a Web-based agent-mediated environment for distributed requirements engineering.

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Spring Distribution Of Ring-Necked Pheasants (Phasianus Colchicus) Following Cattail Reduction With Glyphosate Herbicide, H.J. Homan, G. M. Linz, R.C. Carlson, W.J. Bleier Oct 2003

Spring Distribution Of Ring-Necked Pheasants (Phasianus Colchicus) Following Cattail Reduction With Glyphosate Herbicide, H.J. Homan, G. M. Linz, R.C. Carlson, W.J. Bleier

United States Department of Agriculture Wildlife Services: Staff Publications

To reduce blackbird (Icteridae) damage to field crops in the north-central United States. dense stands of cattail (Typha spp. ) are thinned with glyphosate herbicide. The stands become unusable as roosting and loafing sites, which helps to protect susceptible crops nearby, particularly sunflower (Helianthus annus). Landscape-level impacts of cattail management on non-target avian species have not been studied. We measured use of upland breeding territories by male ring-necked pheasants (Phasianus colchieus) following cattail reduction in wetlands used by pheasants for overwintering. In August 1992, glyphosate was applied to all wetlands with ≥70% cattail coverage in …

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Detection Of West Nile Virus Infection In Birds In The United States By Blocking Elisa And Immunohistochemistry, Martine Jozan, Richard Evans, Robert Mclean, Roy Hall, Basil Tangredi, Lisa Reed, Jamesina Scott Oct 2003

Detection Of West Nile Virus Infection In Birds In The United States By Blocking Elisa And Immunohistochemistry, Martine Jozan, Richard Evans, Robert Mclean, Roy Hall, Basil Tangredi, Lisa Reed, Jamesina Scott

United States Department of Agriculture Wildlife Services: Staff Publications

A blocking ELISA targeting an immunodominant West Nile epitope on the West Nile Virus NSI protein was assessed for the detection of West Nile-specific antibodies in blood samples collected from 584 sentinel chickens and 238 wild birds collected in New Jersey from May-December 2000. Ten mallard ducks (Anus platyrirynchos) experimentally infected with West Nile virus and six uninfected controls were also tested. The ELISA proved specific in detecting WNV antibodies in 9/10 chickens and 414 wild birds previously confirmed as positive by Plaque Reduction Neutralization test (PRNT) at the Center for Disease Control, Division of Vector Borne Diseases, …

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Stored-Crop Loss Due To Deer Consumption, Kurt C. Vercauteren, Michael J. Pipas, Phil Peterson, Scott F. Beckerman Oct 2003

Stored-Crop Loss Due To Deer Consumption, Kurt C. Vercauteren, Michael J. Pipas, Phil Peterson, Scott F. Beckerman

United States Department of Agriculture Wildlife Services: Staff Publications

Deer (Odocoileus spp.) cause an estimated loss of $100 million in United States agricultural production each year (Conover 1997). In 1984 the Wisconsin Department of Agriculture, Trade and Consumer Protection surveyed producers in the state and estimated that white-tailed deer (Odocoileus virginianus) damage to all agricultural products exceeded $36 million annually (Wisconsin Department of Agriculture, Trade and Consumer Protection 1984). Nationwide, for stored crops alone, wildlife reportedly caused $26 million in losses in 1989 (Wywialowski 1994). Despite sometimes biased producer estimates of the value of wildlife-caused losses (Wywialowski 1994), many landowners are willing to accept a …

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Evaluation Of An Animal-Activated Scarecrow And A Monofilament Fence For Reducing Deer Use Of Soybean Fields, Jeff Beringer, Kurt C. Vercauteren, Joshua J. Millspaugh Oct 2003

Evaluation Of An Animal-Activated Scarecrow And A Monofilament Fence For Reducing Deer Use Of Soybean Fields, Jeff Beringer, Kurt C. Vercauteren, Joshua J. Millspaugh

United States Department of Agriculture Wildlife Services: Staff Publications

We measured the efficacy of an animal-activated scarecrow (AAS) and a 5-strand monofilament fence (MF) at reducing white-tailed deer (Odocoileus virginianus) use of 0.4-ha soybean plots in Missouri, USA. Our study design consisted of 9 soybean plots; 3 served as controls, 3 were surrounded by an MF, and 3 were surrounded by an AAS. Data collected for each protected plot included soybean height and weight taken from within and immediately adjacent to 10 unprotected, equally spaced 1 -m2 exclosures. A measure of deer use for each plot was collected with video cameras. A mixed-effects analysis of variance …

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Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt Element Array, Hanning Chen, Scott L. Whittenburg Oct 2003

Magnetic Storage Device Using Induced Magnetic Reversal Of A Cobalt Element Array, Hanning Chen, Scott L. Whittenburg

Chemistry and Biochemistry Faculty Publications

The effects of the applied field, cell size, and cutting area on the ‘‘seed’’ induced magnetic reversal of a cobalt element array have been studied by a stochastic dynamic micromagnetics code using the Laudau–Lifshitz–Gilbert equation. Three magnetic reversal mechanisms under different magnitudes of the applied field have been investigated by examining the energy profiles. To minimize the effect of the thermal fluctuations on the switching time, an applied field with magnitude around 0.7 or 0.8 T and an element array with cutting area less than 10 nm X 10 nm are required. By using the smaller cellsize, the switching time …

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A Fully Snr, Spatial And Temporal Scalable 3dspiht-Based Video Coding Algorithm For Video Streaming Over Heterogeneous Networks, H. Danyali, Alfred Mertins Oct 2003

A Fully Snr, Spatial And Temporal Scalable 3dspiht-Based Video Coding Algorithm For Video Streaming Over Heterogeneous Networks, H. Danyali, Alfred Mertins

Faculty of Informatics - Papers (Archive)

Video streaming over heterogeneous networks (e.g. the Internet) requires high degree of scalability from the video coding. To achieve all types of scalability required for a fully scalable video coding, a modification of the 3DSPIHT algorithm is presented in this paper. The proposed algorithm, called fully scalable 3DSPIHT (FS-3DSPIHT), adds spatial and temporal scalability features to the 3DSPIHT algorithm, through the introduction of resolution dependent lists and a resolution-dependent sorting pass. The important features of the original 3DSPIHT coder such as compression efficiency and full embeddedness are kept. The output bitstream of the FS-3DSPIHT encoder consists of a set of …

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Coarse-Graining Description Of Solid Systems At Nonzero Temperature, Z.-B. Wu, Dennis J. Diestler, Ruqiang Feng, Xiao Cheng Zeng Oct 2003

Coarse-Graining Description Of Solid Systems At Nonzero Temperature, Z.-B. Wu, Dennis J. Diestler, Ruqiang Feng, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The quasicontinuum (QC) technique, in which the atomic lattice of a solid is coarse-grained by overlaying it with a finite-element mesh, has been employed previously to treat the quasistatic evolution of defects in materials at zero temperature. It is extended here to nonzero temperature. A coarse-grained Hamiltonian is derived for the nodes of the mesh, which behave as quasiparticles whose interactions are mediated by the underlying (non-nodal) atoms constrained to move in unison with the nodes. Coarse-grained thermophysical properties are computed by means of the Monte Carlo (MC) method. This dynamically constrained QC MC procedure is applied to a simple …

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Origin And Implications Of The Observed Rhombohedral Phase In Nominally Tetragonal Pb(Zr0.35Ti0.65)O3 Thin Films, Paul C. Mcintyre, Alexei Gruverman, Bryan C. Hendrix, Steven M. Bilodeau, Jeffrey F. Roeder Oct 2003

Origin And Implications Of The Observed Rhombohedral Phase In Nominally Tetragonal Pb(Zr0.35Ti0.65)O3 Thin Films, Paul C. Mcintyre, Alexei Gruverman, Bryan C. Hendrix, Steven M. Bilodeau, Jeffrey F. Roeder

Alexei Gruverman Publications

The structural and electrical properties of Pb(Zr0.35Ti0.65)O3 (PZT) thin films ranging in thickness from 700 to 4000 Å have been investigated. These (001)/(100)-textured films were grown by metalorganic chemical vapor deposition on (111)-textured Ir bottom electrodes. It was observed that, in the as-deposited state, the thinnest PZT films are rhombohedral even though bulk PZT of this composition should be tetragonal. Thicker films have a layered structure with tetragonal PZT at the surface and rhombohedral PZT at the bottom electrode interface. In this article we investigate the origin of this structure and its effect of the …

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Line Segment Distribution Of Sketches For Persian Signature Recognition, A. Chalechale, Alfred Mertins Oct 2003

Line Segment Distribution Of Sketches For Persian Signature Recognition, A. Chalechale, Alfred Mertins

Faculty of Informatics - Papers (Archive)

A novel fast method for line segment extraction based on chain code representation of thinned sketches (or edge maps) is presented and exploited for Persian signature recognition. The method has a parallel nature and can be employed on parallel machines. It breaks the macro chains into several micro chains after applying shifting, smoothing and differentiating. The micro chains are then approximated by straight line segments. Length and position distributions of the extracted line segments are used to make a compact feature vector for Iranian cursive signature. The feature vector is invariant under affine transforms and can be used effectively in …

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Allowed Mesoscopic Point Group Symmetries In Domain Average Engineering Of Perovskite Ferroelectric Crystals, Dorian M. Hatch, H. T. Stokes, W. Cao Oct 2003

Allowed Mesoscopic Point Group Symmetries In Domain Average Engineering Of Perovskite Ferroelectric Crystals, Dorian M. Hatch, H. T. Stokes, W. Cao

Faculty Publications

In multivariant systems, several energetically degenerate low temperature domain states can be produced at the structural phase transition. Coexistence of these domain states can produce mesoscopic structures that possess symmetries distinct from the microscopic single domain crystal symmetry. Such engineered domain structures in certain ferroelectric materials have been proven to give superior piezoelectric properties and extremely soft shear moduli. The objective of this article is to consider the variety of symmetries that can be produced through domain average engineering in proper ferroelectric systems arising from the cubic Pm[overline 3]m symmetry perovskite structure.

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Density Matrix View Of The Double Well Problem, Ronald Lovett Oct 2003

Density Matrix View Of The Double Well Problem, Ronald Lovett

Topics in Quantum Mechanics

No abstract provided.

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Auroral Source Region: Plasma Properties Of The High-Latitude Plasma Sheet, C. A. Kletzing, J. D. Scudder, E. E. Dors, Carina Curto Oct 2003

Auroral Source Region: Plasma Properties Of The High-Latitude Plasma Sheet, C. A. Kletzing, J. D. Scudder, E. E. Dors, Carina Curto

Department of Mathematics: Faculty Publications

Statistical results from a survey of 93 passes through the high-latitude extension of the plasma sheet of electron data from the Hydra instrument on the Polar spacecraft show that the values for electron density can range from 0.01 to 0.5 cm–3 with an average value around 0.1 cm–3 on the poleward side and 0.3 cm–3 on the equatorward side. Electron mean energy is found to have an average value near 900 eV on the equatorward side and 400 eV on the poleward side but varies from 100 eV to 4 keV. These values for density and mean …

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Solar Neutrinos, Sno And Neutrino-Deuteron Reactions, Vladimir Gudkov, Kuniharu Kubodera Oct 2003

Solar Neutrinos, Sno And Neutrino-Deuteron Reactions, Vladimir Gudkov, Kuniharu Kubodera

Faculty Publications

The standard nuclear physics approach and effective field theory approach for calculations of neutrino–deuteron cross sections for the solar neutrino energies are considered. Their main features, the level of accuracy and problems to be addressed for further developments are discussed.

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Storage Coalescing, Delvin C. Defoe Oct 2003

Storage Coalescing, Delvin C. Defoe

All Computer Science and Engineering Research

Typically, when a program executes, it creates objects dynamically and requests storage for its objects from the underlying storage allocator. The patterns of such requests can potentially lead to internal fragmentation as well as external fragmentation. Internal fragmentation occurs when the storage allocator allocates a contiguous block of storage to a program, but the program uses only a fraction of that block to satisfy a request. The unused portion of that block is wasted since the allocator cannot use it to satisfy a subsequent allocation request. External fragmentation, on the other hand, concerns chunks of memory that reside between allocated …

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Integrated Hydrologic And Hydrochemical Observations Of Hidden Creek Lake Jökulhlaups, Kennicott Glacier, Alaska, Suzanne P. Anderson, Joseph S. Walder, Robert S. Anderson, Erin R. Kraal, Michelle Cunico, Andrew G. Fountain, Dennis C. Trabant Oct 2003

Integrated Hydrologic And Hydrochemical Observations Of Hidden Creek Lake Jökulhlaups, Kennicott Glacier, Alaska, Suzanne P. Anderson, Joseph S. Walder, Robert S. Anderson, Erin R. Kraal, Michelle Cunico, Andrew G. Fountain, Dennis C. Trabant

Geology Faculty Publications and Presentations

Hidden Creek Lake (HCL), an ice-marginal lake impounded by Kennicott Glacier, Wrangell Mountains, Alaska, fills annually to ~20 to 30 x ~10⁶ m³ and then drains subglacially within 2 to 3 days. During the 1999 and 2000 jökulhlaups, we carried out a series of planned observations around the lake and in the Kennicott River, which drains the glacier. Approximately 20% of the lake volume was contained within a subglacial water ‘‘wedge’’ beneath the ice dam. The entire volume of the lake drains through the wedge; hydraulic head loss through this constriction may be responsible for the fairly symmetrical shape of …

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Stellar Pollution And [Fe/H] In The Hyades, Aaron Dotter, Brian Chaboyer Oct 2003

Stellar Pollution And [Fe/H] In The Hyades, Aaron Dotter, Brian Chaboyer

Dartmouth Scholarship

The Hyades open cluster presents a unique laboratory for planet formation and stellar pollution studies because all of the stars have essentially the same age and were born from the same cloud of gas. Furthermore, with an age of ~650 Myr, most of the intermediate- and low-mass stars are on the main sequence. Given these assumptions, the accretion of metal-rich material onto the surface of a star during and shortly after the formation of planetary systems should be evident via the enhanced metallicity of the star. Building on previous work, stellar evolution models that include the effects of stellar pollution …

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Constraints From Infrared Space Observatory Data On The Velocity Law And Clumpiness Of Wr 136., R. Ignace, M. F. Quigley, J. P. Cassinelli Oct 2003

Constraints From Infrared Space Observatory Data On The Velocity Law And Clumpiness Of Wr 136., R. Ignace, M. F. Quigley, J. P. Cassinelli

Richard Ignace

Observations with the Infrared Space Observatory (ISO) SWS spectrometer are used to constrain the velocity law and wind clumping of the well-studied Wolf-Rayet (WR) star WR 136 (HD 192163) (WN6). Because the free-free continuum opacity in WR winds increases steadily with wavelength in the IR, each point in the continuous spectrum may be regarded as forming in a pseudo-photosphere of larger radius for longer wavelength. Using this idea in combination with an analysis of the Doppler-broadened widths of several \ion{He}{2} recombination lines, we can derive information about the velocity law and clumpiness of the stellar wind of WR 136. Adopting …

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Heterostructures Of Polymer Photonic Crystal Films, Marc Egen, Rebecca Voss, Bernd Griesebock, Rudolf Zentel, Sergei Romanov, Clivia Sotomayor Torres Oct 2003

Heterostructures Of Polymer Photonic Crystal Films, Marc Egen, Rebecca Voss, Bernd Griesebock, Rudolf Zentel, Sergei Romanov, Clivia Sotomayor Torres

Rebecca Cademartiri

This paper describes ways to multilayer opaline films (opaline heterostructures) composed from functional opal layers of spheres with different lattice constants. At first various monodisperse colloidsboth cross-linked and un-cross-linkedwere prepared from methyl methacrylate, methyl α-chloroacrylate, and methyl α-bromoacrylate. These colloids can be crystallized into large, well-oriented opaline films with the help of a “drawing apparatus” by the method of crystallization in a moving meniscus. After annealing, a second opaline film can be crystallized on top of these films and so on. Electron microscopy inspection shows a sharp borderline between the sublayers and no disorder on both sides although the lattice …

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Final Report On Task 12: Southern Great Basin Seismic Network Operations, James N. Brune, David Von Seggern, Ken Smith, Glenn Biasi Oct 2003

Final Report On Task 12: Southern Great Basin Seismic Network Operations, James N. Brune, David Von Seggern, Ken Smith, Glenn Biasi

Publications (YM)

The Nevada Seismological Laboratory began seismic monitoring operations under the DOE-UCCSN Cooperative Agreement on 11/01/1999. This final report summarizes our activities and studies made in the four years up to 09/30/2003. Previously, NSL operated under the M&O for the Yucca Mountain Project from October 1995 through September 1999 and under the U. S. Geological Survey from October 1992 through September 1995. For purposes of this report, earthquakes occurring in the years FY1998 and FY1999 were analyzed in the first two years of the NSL’s involvement with the Cooperative Agreement, and they will be treated here, along with the data in …

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A Nested Unsupervised Approach To Identifying Novel Molecular Subtypes, Elizabeth Garrett, Giovanni Parmigiani Oct 2003

A Nested Unsupervised Approach To Identifying Novel Molecular Subtypes, Elizabeth Garrett, Giovanni Parmigiani

Johns Hopkins University, Dept. of Biostatistics Working Papers

In classification problems arising in genomics research it is common to study populations for which a broad class assignment is known (say, normal versus diseased) and one seeks to find undiscovered subclasses within one or both of the known classes. Formally, this problem can be thought of as an unsupervised analysis nested within a supervised one. Here we take the view that the nested unsupervised analysis can successfully utilize information from the entire data set for constructing and/or selecting useful predictors. Specifically, we propose a mixture model approach to the nested unsupervised problem, where the supervised information is used to …

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Ξ‾ And Ω Distributions In Hadron–Nucleus Interactions, R. Vogt, Thomas D. Gutierrez Oct 2003

Ξ‾ And Ω Distributions In Hadron–Nucleus Interactions, R. Vogt, Thomas D. Gutierrez

Physics

Strange baryons have long been known to exhibit a leading particle effect. A recent comparison of Ξ‾ production in π‾, n, and Σ‾ interactions with nuclei show this effect clearly. These data are supplemented by earlier measurements of Ξ‾ and Ω production by a Ξ‾ beam. We calculate the Ξ‾ and Ω xF distributions and nuclear dependence in hA interactions using the intrinsic model.

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Measurement Of Anti-Cancer Agent Methoxyamine In Plasma By Tandem Mass Spectrometry With On-Line Sample Extraction, Shuming Yang, Lili Liu, Stanton L. Gerson, Yan Xu Oct 2003

Measurement Of Anti-Cancer Agent Methoxyamine In Plasma By Tandem Mass Spectrometry With On-Line Sample Extraction, Shuming Yang, Lili Liu, Stanton L. Gerson, Yan Xu

Chemistry Faculty Publications

In this work, we present the development and validation of a tandem mass spectrometry method for the quantitative determination of methoxyamine (CH3ONH2), a potential new chemotherapeutic agent, in human and mouse plasma. Methoxyamine together with the internal standard (I.S.) methoxyl-D3-amine was directly derivatized in plasma sample with a novel chemical agent 4-(N,N-diethylamino)benzaldehyde. The product solution was injected into an on-line Oasis® HLB extraction column ( mm) for analyte extraction. After the elution of extractives, the derivatized analytes were monitored by the positive-electrospray-ionization mass spectrometry (ESI-MS-MS). The structures of derivatized analytes were elucidated by fragmentation. Quantitation of plasma methoxyamine was carried …

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