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Faculty Publications

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Articles 2431 - 2460 of 3797

Full-Text Articles in Physical Sciences and Mathematics

Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky Jan 2008

Testing The Nature Of S0 Galaxies Using Planetary Nebula Kinematics In Ngc 1023, E. Noordermeer, M. R. Merrifield, L. Coccato, M. Arnaboldi, M. Capaccioli, N. G. Douglas, K. C. Freeman, O. Gerhard, K. Kuijken, F. De Lorenzi, N. R. Napolitano, Aaron J. Romanowsky

Faculty Publications

We investigate the manner in which lenticular galaxies are formed by studying their stellar kinematics: an S0 formed from a fading spiral galaxy should display similar cold outer disc kinematics to its progenitor, while an S0 formed in a minor merger should be more dominated by random motions. In a pilot study, an attempt to distinguish between these scenarios, we have measured the planetary nebula (PN) kinematics of the nearby S0 system NGC 1023. Using the Planetary Nebula Spectrograph, we have detected and measured the line-of-sight velocities of 204 candidate planetary nebulae (PNe) in the field of this galaxy. Out …

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The Dark Matter Halo Of Ngc 1399- Cdm Or Mond?, T. Richtler, Y. Schuberth, M. Hilker, B. Dirsch, L. Bassino, Aaron J. Romanowsky Jan 2008

The Dark Matter Halo Of Ngc 1399- Cdm Or Mond?, T. Richtler, Y. Schuberth, M. Hilker, B. Dirsch, L. Bassino, Aaron J. Romanowsky

Faculty Publications

Context. Central galaxies in galaxy clusters may be key discriminants in the competition between the cold dark matter (CDM) paradigm and modified Newtonian dynamics (MOND). Aims. We investigate the dark halo of NGC 1399, the central galaxy of the Fornax cluster, out to a galactocentric distance of 80 kpc. Methods.The data base consists of 656 radial velocities of globular clusters obtained with MXU/VLT and GMOS/Gemini, which is the largest sample so far for any galaxy. We performed a Jeans analysis for a non-rotating isotropic model. Results.An NFW halo with the parameters $r_{\rm s} = 50\,\rm {kpc}$ and $\varrho_{\rm s} = …

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Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya Jan 2008

Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya

Faculty Publications

A high-throughput high-sensitivity optical technique for measuringmagnetostriction of thin-film composition-spread samples has been developed. It determines the magnetostriction by measuring the induced deflection of micromachined cantilever unimorph samples. Magnetostrictionmeasurements have been performed on as-deposited Fe–Ga and Fe–Ga–Al thin-film composition spreads. The thin-film Fe–Ga spreads display a similar compositional variation of magnetostriction as bulk. A previously undiscovered peak in magnetostriction at low Ga content was also observed and attributed to a maximum in the magnetocrystalline anisotropy. Magnetostrictive mapping of the Fe–Ga–Al ternary system reveals the possibility of substituting up to 8at.%Al in Fe70Ga30 without significant degradation of magnetostriction.

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Network Formation Using Ant Colony Optimization -- A Systematic Review, Steven C. Oimoen, Gilbert L. Peterson, Kenneth M. Hopkinson Jan 2008

Network Formation Using Ant Colony Optimization -- A Systematic Review, Steven C. Oimoen, Gilbert L. Peterson, Kenneth M. Hopkinson

Faculty Publications

A significant area of research in the field of hybrid communications is the Network Design Problem (NDP) [1]. The NDP is an NP complete problem [1] that focuses on identifying the optimal network topology for transmitting commodities between nodes, under constraints such as bandwidth, limited compatible directed channels, and link and commodity costs. The NDP focuses on designing a flexible network while trying to achieve optimal flow or routing. If a link (or arc) is used, then an associated fixed cost of the edge is incurred. In addition, there is a cost for using the arc depending on the flow. …

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High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi Jan 2008

High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas J. Wyrobek, Oden L. Warren, Jason R. Hattrick-Simpers, Olubenga O. Famodu, Ichiro Takeuchi

Faculty Publications

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the …

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Bipartite Toughness And The K-Factors In Bipartite Graphs, Guizhen Liu, Jianbo Quan, Jonathan Z. Sun, Rui Xu Jan 2008

Bipartite Toughness And The K-Factors In Bipartite Graphs, Guizhen Liu, Jianbo Quan, Jonathan Z. Sun, Rui Xu

Faculty Publications

We define a new invariant tB(G) in bipartite graphs that is analogous to the toughness t(G) and we give sufficient conditions in term of tB(G) for the existence of k-factors in bipartite graphs. We also show that these results are sharp.

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Tetra-μ-Aqua-Octaaquabis(μ-4-Chloropyridine-2,6-Dicarboxylato(Bis(4-Chloro-Pyridine-2,6-Dicarboxylato)Tricobalt(Ii)-Disodium(I) Bis[Triaquabis(4-Chloro-Pyridine-2,6-Dicarboxylato)Cobalt(Ii)] Hexahydrate, Lamaryet Moody, Shawna Balof, Shanika Smith, Varma H. Rambaran, Don Vanderveer, Alvin A. Holder Jan 2008

Tetra-μ-Aqua-Octaaquabis(μ-4-Chloropyridine-2,6-Dicarboxylato(Bis(4-Chloro-Pyridine-2,6-Dicarboxylato)Tricobalt(Ii)-Disodium(I) Bis[Triaquabis(4-Chloro-Pyridine-2,6-Dicarboxylato)Cobalt(Ii)] Hexahydrate, Lamaryet Moody, Shawna Balof, Shanika Smith, Varma H. Rambaran, Don Vanderveer, Alvin A. Holder

Faculty Publications

The title compound, [Co3Na2(C72ClNO4)4(H2O)12][Co(C7H2ClNO4(H2O)3]2·6H2O, consists of a centrosymmetric dimer of [CoII(dipicCl)2]2- complex dianions [dipicCl is 4-chloro­pyridine-2,6-dicarboxyl­ate] bridged by an [Na2CoII(H2O)12]4+ tetra­cationic cluster, two independent [Co(dipicCl)(H2O)3] complexes, and six water mol­ecules of crystallization. The metals are all six-coordinate with distorted octahedral geometries. The [CoII(dipicCl)(H2O)3] complexes are neutral, with …

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Learning Policies For Embodied Virtual Agents Through Demonstration, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura Jan 2008

Learning Policies For Embodied Virtual Agents Through Demonstration, Jonathan Dinerstein, Parris K. Egbert, Dan A. Ventura

Faculty Publications

Although many powerful AI and machine learning techniques exist, it remains difficult to quickly create AI for embodied virtual agents that produces visually lifelike behavior. This is important for applications (e.g., games, simulators, interactive displays) where an agent must behave in a manner that appears human-like. We present a novel technique for learning reactive policies that mimic demonstrated human behavior. The user demonstrates the desired behavior by dictating the agent’s actions during an interactive animation. Later, when the agent is to behave autonomously, the recorded data is generalized to form a continuous state-to-action mapping. Combined with an appropriate animation algorithm …

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Adapting Adtrees For High Arity Features, Irene Langkilde-Geary, Robert Van Dam, Dan A. Ventura Jan 2008

Adapting Adtrees For High Arity Features, Irene Langkilde-Geary, Robert Van Dam, Dan A. Ventura

Faculty Publications

ADtrees, a data structure useful for caching sufficient statistics, have been successfully adapted to grow lazily when memory is limited and to update sequentially with an incrementally updated dataset. For low arity symbolic features, ADtrees trade a slight increase in query time for a reduction in overall tree size. Unfortunately, for high arity features, the same technique can often result in a very large increase in query time and a nearly negligible tree size reduction. In the dynamic (lazy) version of the tree, both query time and tree size can increase for some applications. Here we present two modifications to …

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Sentiment Regression: Using Real-Valued Scores To Summarize Overall Document Sentiment, Adam Drake, Eric K. Ringger, Dan A. Ventura Jan 2008

Sentiment Regression: Using Real-Valued Scores To Summarize Overall Document Sentiment, Adam Drake, Eric K. Ringger, Dan A. Ventura

Faculty Publications

In this paper, we consider a sentiment regression problem: summarizing the overall sentiment of a review with a real-valued score. Empirical results on a set of labeled reviews show that real-valued sentiment modeling is feasible, as several algorithms improve upon baseline performance. We also analyze performance as the granularity of the classification problem moves from two-class (positive vs. negative) towards infinite-class (real-valued).

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A Reductio Ad Absurdum Experiment In Sufficiency For Evaluating (Computational) Creative Systems, Dan A. Ventura Jan 2008

A Reductio Ad Absurdum Experiment In Sufficiency For Evaluating (Computational) Creative Systems, Dan A. Ventura

Faculty Publications

We consider a combination of two recent proposals for characterizing computational creativity and explore the sufficiency of the resultant framework. We do this in the form of a gedanken experiment designed to expose the nature of the framework, what it has to say about computational creativity, how it might be improved and what questions this raises.

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Determining The Refractive Index In The Extreme Ultraviolet Using Kramers-Kronig On Thin-Film Scandium Oxide Transmission Data, David D. Allred, Jacqualine J. Butterfield Jan 2008

Determining The Refractive Index In The Extreme Ultraviolet Using Kramers-Kronig On Thin-Film Scandium Oxide Transmission Data, David D. Allred, Jacqualine J. Butterfield

Faculty Publications

Whereas the real part of the refractive index is dependent on both transmittance and reflectance, the imaginary part can be determined from transmittance data alone. It is possible to use Kramers-Kronig analysis to calculate the real part if the imaginary part is known over a sufficiently broad range. We show that the delta calculated from reflection and transmission data without taking into account roughness may underestimate the real part of the refractive index of the scandium oxide samples we are studying by up to 40% near 270 eV.

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Nanoscale Characterization Of Thin Film Coatings Using Annular Dark Field Scanning Transmission Electron Microscopy, Guillermo Acosta, Richard Vanfleet, David D. Allred Jan 2008

Nanoscale Characterization Of Thin Film Coatings Using Annular Dark Field Scanning Transmission Electron Microscopy, Guillermo Acosta, Richard Vanfleet, David D. Allred

Faculty Publications

When considering the optical performance of thin films in the Extreme Ultraviolet (EUV), developing an accurate physical description of a thin film coating is necessary to be able to successfully model optical performance. With the short wavelengths of the EUV, film interfaces and sample roughness warrant special attention and care. The surfaces of thin film samples are routinely measured by Atomic Force Microscopy, from which roughness can be determined. However, characterizing the quality of interfaces below the surface is much more challenging. In a recent study of scandium oxide thin films, High Resolution Transmission Electron Microscopy and Annular Dark Field …

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Utilizing Phrase-Similarity Measures For Detecting And Clustering Informative Rss News Articles, Yiu-Kai D. Ng, Maria Soledad Pera Jan 2008

Utilizing Phrase-Similarity Measures For Detecting And Clustering Informative Rss News Articles, Yiu-Kai D. Ng, Maria Soledad Pera

Faculty Publications

As the number of RSS news feeds continue to increase over the Internet, it becomes necessary to minimize the workload of the user who is otherwise required to scan through huge numbers of news articles to find related articles of interest, which is a tedious and often an impossible task. In order to solve this problem, we present a novel approach, called InFRSS, which consists of a correlation-based phrase matching (CPM) model and a fuzzy compatibility clustering (FCC) model. CPM can detect RSS news articles containing phrases that are the same as well as semantically alike, and dictate the degrees …

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Automatic Composition Of Themed Mood Pieces, Heather Chan, Dan A. Ventura Jan 2008

Automatic Composition Of Themed Mood Pieces, Heather Chan, Dan A. Ventura

Faculty Publications

Musical harmonization of a given melody is a nontrivial problem; slight variations in instrumentation, voicing, texture, and bass rhythm can lead to significant differences in the mood of the resulting piece. This study explores the possibility of automatic musical composition by using machine learning and statistical natural language processing to tailor a piece to a particular mood using an existing melody.

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Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, I. A. Bilenko, Tiffany Z. Summerscales Jan 2008

Beating The Spin-Down Limit On Gravitational Wave Emission From The Crab Pulsar, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, I. A. Bilenko, Tiffany Z. Summerscales

Faculty Publications

We present direct upper limits on gravitational wave emission from the Crab pulsar using data from the first 9 months of the fifth science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). These limits are based on two searches. In the first we assume that the gravitational wave emission follows the observed radio timing, giving an upper limit on gravitational wave emission that beats indirect limits inferred from the spin-down and braking index of the pulsar and the energetics of the nebula. In the second we allow for a small mismatch between the gravitational and radio signal frequencies and interpret …

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First Joint Search For Gravitational-Wave Bursts In Ligo And Geo 600 Data, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, I. Bartos, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, Tiffany Z. Summerscales Jan 2008

First Joint Search For Gravitational-Wave Bursts In Ligo And Geo 600 Data, B. Abbott, R. Abbott, R. Adhikari, P. Ajith, B. Allen, G. Allen, R. Amin, S. B. Anderson, W. G. Anderson, M. A. Arain, M. Araya, H. Armandula, P. Armor, Y. Aso, S. Aston, P. Aufmuth, C. Aulbert, S. Babak, S. Ballmer, H. Bantilan, B. C. Barish, C. Barker, D. Barker, B. Barr, P. Barriga, M. A. Barton, I. Bartos, M. Bastarrika, K. Bayer, J. Betzwieser, P. T. Beyersdorf, Tiffany Z. Summerscales

Faculty Publications

We present the results of the first joint search for gravitational-wave bursts by the LIGO and GEO 600 detectors. We search for bursts with characteristic central frequencies in the band 768-2048 Hz in the data acquired between 22 February and 23 March, 2005 (fourth LSC Science Run-S4). We discuss the inclusion of the GEO 600 data in the Waveburst-CorrPower pipeline that first searches for coincident excess power events without taking into account differences in the antenna responses or strain sensitivities of the various detectors. We compare the performance of this pipeline to that of the coherent Waveburst pipeline based on …

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Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich Jan 2008

Time Reversal, Brian E. Anderson, Michele Griffa, Paul A. Johnson, Carene Larmat, Timothy J. Ulrich

Faculty Publications

This article provides an historical overview of Time Reversal (TR), introduces its basic physics, addresses advantages and limitations, and describes some applications of this very active research area of acoustics. In the Geophysics Group at the Los Alamos National Laboratory, we conduct studies of TR of elastic waves in solids. Our work includes application of TR to nondestructive evaluation of materials, as well as to earthquake source characterization, and ground-based nuclear explosion monitoring. We emphasize the term elastic waves here to underscore that we include both compression and shear waves, in contrast to purely acoustic waves that are only compressional.

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Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey Jan 2008

Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey

Faculty Publications

This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (RX) and quality factor (Q) with the resonators’ silicon layer thickness (tSi). For identical lateral dimensions and PZT-layer thicknesses (tPZT), the PZT-on-silicon resonator has higher resonant frequency (fC), higher Q (5100 versus 140), lower RX (51 Ω versus 205 Ω), and better linearity [third-order input intercept …

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Alternative Parametric Boundary Reconstruction Method For Biomedical Imaging, Joseph Kolibal, Daniel Howard Jan 2008

Alternative Parametric Boundary Reconstruction Method For Biomedical Imaging, Joseph Kolibal, Daniel Howard

Faculty Publications

Determining the outline or boundary contour of a two-dimensional object, or the surface of a three-dimensional object poses difficulties particularly when there is substantial measurement noise or uncertainty. By adapting the mathematical approach of stochastic function recovery to this task, it is possible to obtain usable estimates for these boundaries, even in the presence of large amounts of noise. The technique is applied to parametric boundary data and has potential applications in biomedical imaging. It should be considered as one of several techniques to improve the visualization of images. Copyright (C) 2008 J. Kolibal and D. Howard.

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Symmetric Groups And Conjugacy Classes, Edith Adan-Bante, Helena Verrill Jan 2008

Symmetric Groups And Conjugacy Classes, Edith Adan-Bante, Helena Verrill

Faculty Publications

Let S, be the symmetric group of degree n where n > 5. Given any non-trivial alpha,beta is an element of S-n, we prove that the product alpha(Sn)beta(Sn) of the conjugacy classes alpha(Sn) and beta(Sn) is never a conjugacy class. Furthermore, if n is odd and not a multiple of three, then alpha(Sn)beta(Sn) is the union of at least three distinct conjugacy classes. We also describe the elements alpha,beta is an element of S-n in the case when alpha(Sn)beta(Sn) is the union of exactly two distinct conjugacy classes.

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Selecting U.S. Senators By The Original Method: Intersecting Mathematics And Social Studies, Bonnie H. Litwiller, David R. Duncan Jan 2008

Selecting U.S. Senators By The Original Method: Intersecting Mathematics And Social Studies, Bonnie H. Litwiller, David R. Duncan

Faculty Publications

Mathematics teachers are concerned with incorporating connections with other academic areas in their mathematics curriculum. Social science provides a rich source of data which can be collected, organized, and interpreted by mathematics students. These data become of particular interest to many students if they involve political questions and processes.

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Tidal Asymmetry And Residual Circulation Over Linear Sandbanks And Their Implication On Sediment Transport: A Process-Oriented Numerical Study, Rosario Sanay, George Voulgaris, John C. Warner Dec 2007

Tidal Asymmetry And Residual Circulation Over Linear Sandbanks And Their Implication On Sediment Transport: A Process-Oriented Numerical Study, Rosario Sanay, George Voulgaris, John C. Warner

Faculty Publications

A series of process-oriented numerical simulations is carried out in order to evaluate the relative role of locally generated residual flow and overtides on net sediment transport over linear sandbanks. The idealized bathymetry and forcing are similar to those present in the Norfolk Sandbanks, North Sea. The importance of bottom drag parameterization and bank orientation with respect to the ambient flow is examined in terms of residual flow and overtide generation, and subsequent sediment transport implications are discussed. The results show that although the magnitudes of residual flow and overtides are sensitive to bottom roughness parameterization and bank orientation, the …

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Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Measurement Of (Anti)Deuteron And (Anti)Proton Production In Dis At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3 < pT / M < 0.7. The particle rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements. © 2007 Elsevier B.V. All rights reserved.

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Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Multijet Production At Low XBj In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

Inclusive dijet and trijet production in deep inelastic ep scattering has been measured for 10 < Q2 < 100 GeV2 and low Bjorken x, 10-4 < xBj < 10-2. The data were taken at the HERA ep collider with centre-of-mass energy sqrt(s) = 318 GeV using the ZEUS detector and correspond to an integrated luminosity of 82 pb-1. Jets were identified in the hadronic centre-of-mass (HCM) frame using the kT cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of Q2, xBj, jet transverse energy, and jet pseudorapidity. As a further examination of low-xBj dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at O (αs3) generally describe the trijet data well and improve the description of the dijet data compared to the calculation at O (αs2). © 2007 Elsevier B.V. All rights reserved.

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). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li Dec 2007

). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li

Faculty Publications

Relation between the elastic modulus and the diameter (D) of ZnOnanowires was elucidated using a model with the calculated ZnOsurface stresses as input. We predict for ZnOnanowires due to surface stress effect: (1) when D>20nm, the elastic modulus would be lower than the bulk modulus and decrease with the decreasing diameter, (2) when 20nm>D>2nm, the nanowires with a longer length and a wurtzite crystal structure could be mechanically unstable, and (3) when D<2nm, the elastic modulus would be higher than that of the bulk value and increase with a decrease in nanowire diameter.

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Hunting For Hydrothermal Vents Along The Galápagos Spreading Center, Rachel M. Haymon, Edward T. Baker, Joseph A. Resing, Scott M. White, Ken C. Macdonald Dec 2007

Hunting For Hydrothermal Vents Along The Galápagos Spreading Center, Rachel M. Haymon, Edward T. Baker, Joseph A. Resing, Scott M. White, Ken C. Macdonald

Faculty Publications

No abstract provided.

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Dijet Production In Diffractive Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi Dec 2007

Dijet Production In Diffractive Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 61 pb-1. The dijet cross section has been measured for virtualities of the exchanged virtual photon, 5 < Q2 < 100 GeV2, and γ*p centre-of-mass energies, 100 < W < 250 GeV. The jets, identified using the inclusive kT algorithm in the γ*p frame, were required to have a transverse energy E* T,jet > 4 GeV and the jet with the highest transverse energy was required to have E* T,jet > 5 GeV. All jets were required to be in the pseudorapidity range -3.5

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New Ways To Collect Data In The Antarctic, Walker O. Smith, Vernon Asper Nov 2007

New Ways To Collect Data In The Antarctic, Walker O. Smith, Vernon Asper

Faculty Publications

Conducting Antarctic research is challenging. Not only is the environment difficult, given low temperatures, high winds, and ice cover, but also the availability of sampling platforms is limited. The U.S. National Science Foundation has only two vessels that can routinely operate in ice‐covered waters, the research vessel/icebreaker N.B. Palmer and the Antarctic research support vessel L.M. Gould. The restricted availability of vessels makes research operations difficult to schedule, especially during austral spring and summer. Traditional sampling methods (those confined to ships and moorings) have provided insights into distributions and processes in the Southern Ocean, but new research questions require new …

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1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev Nov 2007

1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Kis(Trifluoro­Meth­Yl)- 1,3,7,10,14,17,21,28,31,42,52,55-Dodeca­Hydro­(C60-IH)[5,6]Fullerene, Natalia B. Shustova Prof. Dr., O.P. Anderson, O. V. Boltalina, S. H. Strauss, I. E. Kareev

Faculty Publications

The title compound, C72F36, is one of four isomers of C60(CF3)12 for which crystal structures have been obtained. The fullerene mol­ecule has an idealized Ih C60 core with the 12 CF3 groups arranged in an asymmetric fashion on two ribbons of edge-sharing C6(CF3)2 hexa­gons, a para–meta–para–para–para–meta–para ribbon and a para–meta–para ribbon, giving an overall pmp 3 mp,pmp structure. There are no cage Csp 3 …

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