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Faculty Publications

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Articles 2521 - 2550 of 3797

Full-Text Articles in Physical Sciences and Mathematics

Jet-Radius Dependence Of Inclusive-Jet Cross Sections In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, 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, L. Rinaldi May 2007

Jet-Radius Dependence Of Inclusive-Jet Cross Sections In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, 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, L. Rinaldi

Faculty Publications

Differential inclusive-jet cross sections have been measured for different jet radii in neutral current deep inelastic ep scattering for boson virtualities Q2 > 125 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb-1. Jets were identified in the Breit frame using the kT cluster algorithm in the longitudinally inclusive mode for different values of the jet radius R. Differential cross sections are presented as functions of Q2 and the jet transverse energy, ET, Bjet. The dependence on R of the inclusive-jet cross section has been measured for Q2 > 125 and 500 GeV2 and found to be …

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Sea Surface Pco2‐Sst Relationships Across A Cold‐Core Cyclonic Eddy: Implications For Understanding Regional Variability And Air‐Sea Gas Exchange, Feizhou Chen, Wei‐Jun Cai, Claudia R. Benitez-Nelson, Yongchen Wang May 2007

Sea Surface Pco2‐Sst Relationships Across A Cold‐Core Cyclonic Eddy: Implications For Understanding Regional Variability And Air‐Sea Gas Exchange, Feizhou Chen, Wei‐Jun Cai, Claudia R. Benitez-Nelson, Yongchen Wang

Faculty Publications

[1] This study is designed to improve the understanding of how biologically productive, cold‐core cyclonic eddies affect sea surface pCO2 in the lee of the main Hawaiian Islands in the subtropical North Pacific Gyre. We identified three unique relationships between pCO2 and sea surface temperature (SST). A positive correlation between pCO2 and SST was observed in the waters surrounding the eddy suggesting surface CO2 is controlled primarily by thermodynamics. In contrast, a negative relationship was observed within the eddy core as a result of the upwelling of CO2‐enriched subsurface waters. A third relationship existed throughout the rest …

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Spin Blockade At Semiconductor/Ferromagnet Junctions, Yuriy V. Pershin Dr, Massimiliano Di Ventra May 2007

Spin Blockade At Semiconductor/Ferromagnet Junctions, Yuriy V. Pershin Dr, Massimiliano Di Ventra

Faculty Publications

We study theoretically extraction of spin-polarized electrons at nonmagnetic semiconductor/ferromagnet junctions. The outflow of majority-spin electrons from the semiconductor into the ferromagnet leaves a cloud of minority-spin electrons in the semiconductor region near the junction, forming a local spin-dipole configuration at the semiconductor/ferromagnet interface. This minority-spin cloud can limit the majority-spin current through the junction, creating a pronounced spin blockade at a critical current. We calculate the critical spin-blockade current in both planar and cylindrical geometries and discuss possible experimental tests of our predictions.

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Probabilistic Searching Using A Small Unmanned Aerial Vehicle, Steven R. Hansen, Timothy W. Mclain, Michael A. Goodrich May 2007

Probabilistic Searching Using A Small Unmanned Aerial Vehicle, Steven R. Hansen, Timothy W. Mclain, Michael A. Goodrich

Faculty Publications

Ground breaking concepts in optimal search theory were developed during World War II by the U.S. Navy. These concepts use an assumed detection model to calculate a detection probability rate and an optimal search allocation. Although this theory is useful in determining when and where search effort should be applied, it offers little guidance for the planning of search paths. This paper explains how search theory can be applied to path planning for an SUAV with a fixed CCD camera. Three search strategies are developed: greedy search, contour search, and composite search. In addition, the concepts of search efficiency and …

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To Repair Or Not To Repair: Helping Ad Hoc Routing Protocols To Distinguish Mobility From Congestion, Qiuyi Duan, Roger Pack, Manoj Pandey, Lei Wang, Daniel Zappala May 2007

To Repair Or Not To Repair: Helping Ad Hoc Routing Protocols To Distinguish Mobility From Congestion, Qiuyi Duan, Roger Pack, Manoj Pandey, Lei Wang, Daniel Zappala

Faculty Publications

In this paper we consider the problem of distinguishing whether frame loss at the MAC layer has occurred due to mobility or congestion. Most ad hoc routing protocols make the faulty assumption that all frame loss means the destination node has moved, resulting in significant overhead as they initiate the repair of routes that have not been broken. We design a mobility detection algorithm, MDA, that properly detects the cause of a lost frame, then coordinates with the routing protocol so that it reacts properly. This approach dramatically reduces routing protocol overhead and significantly increases application throughput. We use a …

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Anomalous Magnetic Field Dependence Of The T1 Spin Lifetime In A Lightly Doped Gaas Sample, John S. Colton, M. E. Heeb, P. Schroeder, A. Stokes, L. R. Wienkes, A. S. Bracker May 2007

Anomalous Magnetic Field Dependence Of The T1 Spin Lifetime In A Lightly Doped Gaas Sample, John S. Colton, M. E. Heeb, P. Schroeder, A. Stokes, L. R. Wienkes, A. S. Bracker

Faculty Publications

The T1 spin lifetime of a lightly doped n-type GaAs sample has been measured via time-resolved polarization spectroscopy under a number of temperature and magnetic field conditions. Lifetimes up to 19 μs have been measured. The magnetic field dependence of T1 shows a nonmonotonic behavior, where the spin lifetime first increases, then decreases, then increases again with field. The initial increase in T1 is understood to be due to correlation between electrons localized on donors. The decrease in T1 is likely due to phonon-related spin-orbit relaxation. The final increase in T1 with B indicates a suppression of the spin-orbit relaxation …

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Model-Independent Measurement Of The Excited Fraction In A Magneto-Optical Trap, M. H. Shah, H. A. Camp, M. L. Trachy, G. Veshapidze, M.A. Gearba, B.D. Depaola May 2007

Model-Independent Measurement Of The Excited Fraction In A Magneto-Optical Trap, M. H. Shah, H. A. Camp, M. L. Trachy, G. Veshapidze, M.A. Gearba, B.D. Depaola

Faculty Publications

In many experiments involving a magneto-optical trap (MOT) it is of great importance to know the fraction of atoms placed in an excited state due to the trapping process. Generally speaking, researchers have had to use overly simplistic and untested models to estimate this fraction. In this work, the excited fractions of 87Rb atoms in a MOT are directly measured using a charge transfer technique, for a range of MOT parameters. Simple models are then fit to the measured fractions. Using the results of this work, the excited fraction of 87Rb atoms trapped in a MOT can be …

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Products Of Characters With Few Irreducible Constituents, Edith Adan-Bante May 2007

Products Of Characters With Few Irreducible Constituents, Edith Adan-Bante

Faculty Publications

We study the solvable groups G that have an irreducible character χ ∈ Irr(G) such that χ--χ has at most two nonprincipal irreducible constituents.

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Computation Of Correlation Functions And Wave Function Projections In The Context Of Quantum Trajectory Dynamics, Sophya Garashchuk Apr 2007

Computation Of Correlation Functions And Wave Function Projections In The Context Of Quantum Trajectory Dynamics, Sophya Garashchuk

Faculty Publications

The de Broglie-Bohm formulation of the Schrödinger equation implies conservation of the wave function probability density associated with each quantum trajectory in closed systems. This conservation property greatly simplifies numerical implementations of the quantum trajectory dynamics and increases its accuracy. The reconstruction of a wave function, however, becomes expensive or inaccurate as it requires fitting or interpolation procedures. In this paper we present a method of computing wave packet correlation functions and wave function projections, which typically contain all the desired information about dynamics, without the full knowledge of the wave function by making quadratic expansions of the wave function …

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Optically Induced Suppression Of Spin Relaxation In Two-Dimensional Electron Systems With Rashba Interaction, Yuriy V. Pershin Dr Apr 2007

Optically Induced Suppression Of Spin Relaxation In Two-Dimensional Electron Systems With Rashba Interaction, Yuriy V. Pershin Dr

Faculty Publications

A pulsed technique for electrons in two-dimensional systems, in some ways analogous to spin echo in nuclear magnetic resonance, is discussed. We show that a sequence of optical below-band-gap pulses can be used to suppress the electron spin relaxation due to the D’yakonov-Perel’ spin relaxation mechanism. The spin relaxation time is calculated for several pulse sequences within a Monte Carlo simulation scheme. The maximum of the spin relaxation time as a function of magnitude or width of the pulses corresponds to a π pulse. It is important that even relatively distant pulses efficiently suppress spin relaxation.

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Squares Of Characters And Finite Groups, Edith Adan-Bante Apr 2007

Squares Of Characters And Finite Groups, Edith Adan-Bante

Faculty Publications

Let G be a finite group and χ be an irreducible complex character. We study the character χ2 in the case that χ(1) is a prime power.

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Hikorocodium Endo Is Not An Alga But An Inozoid Sponge, J. Keith Rigby, Baba Senowbari-Daryan Apr 2007

Hikorocodium Endo Is Not An Alga But An Inozoid Sponge, J. Keith Rigby, Baba Senowbari-Daryan

Faculty Publications

The genus Hikorocodium, with the type species Hikorocodium elegantae from the Permian of Japan, was described originally as a codiacean alga by Endo. It is not a codiacean alga but an inozoid sponge of the family Preperonidellidae. Several fossils described later by Endo and other authors as H. elegantae should be assigned to different inozoid sponge taxa. Specimens of H. fertiliz, described by Endo from the Jurassic of Japan, are also sponge fragments. The taxonomic positions of H. transversum Endo and H. kuramotoi Nakamura, as sponges or

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Accumulation Of Pathological Tau Species And Memory Loss In A Conditional Model Of Tauopathy, Zdenek Berger, Hanno Roder, Amanda Hanna, Vijayaraghavan Rangachari, Mei Yue, Zbigniew Wszolek, Karen Ashe, Joshua Knight, Dennis Dickson, Cathy Andorfer, Terrone L. Rosenberry, Jada Lewis, Mike Hutton, Christopher Janus Apr 2007

Accumulation Of Pathological Tau Species And Memory Loss In A Conditional Model Of Tauopathy, Zdenek Berger, Hanno Roder, Amanda Hanna, Vijayaraghavan Rangachari, Mei Yue, Zbigniew Wszolek, Karen Ashe, Joshua Knight, Dennis Dickson, Cathy Andorfer, Terrone L. Rosenberry, Jada Lewis, Mike Hutton, Christopher Janus

Faculty Publications

Neurofibrillary tangles (NFTs) are a pathological hallmark of Alzheimer's disease and other tauopathies, but recent studies in a conditional mouse model of tauopathy (rTg4510) have suggested that NFT formation can be dissociated from memory loss and neurodegeneration. This suggests that NFTs are not the major neurotoxic tau species, at least during the early stages of pathogenesis. To identify other neurotoxic tau protein species, we performed biochemical analyses on brain tissues from the rTg4510 mouse model and then correlated the levels of these tau proteins with memory loss. We describe the identification and characterization of two forms of tau multimers (140 …

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Event Shapes In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli Apr 2007

Event Shapes In Deep Inelastic Scattering At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli

Faculty Publications

Mean values and differential distributions of event-shape variables have been studied in neutral current deep inelastic scattering using an integrated luminosity of 82.2 pb-1 collected with the ZEUS detector at HERA. The kinematic range is 80 < Q2 < 20 480 GeV2 and 0.0024 < x < 0.6, where Q2 is the virtuality of the exchanged boson and x is the Bjorken variable. The data are compared with a model based on a combination of next-to-leading-order QCD calculations with next-to-leading-logarithm corrections and the Dokshitzer-Webber non-perturbative power corrections. The power-correction method provides a reasonable description of the data for all event-shape variables studied. Nevertheless, the lack of consistency of the determination of αs and of the non-perturbative parameter of the model, over(α0, -), suggests the importance of higher-order processes that are not yet included in the model. © 2006 Elsevier B.V. All rights reserved.

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Steganalysis Feature Improvement Using Expectation Maximization, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian Apr 2007

Steganalysis Feature Improvement Using Expectation Maximization, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian

Faculty Publications

No abstract provided.

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High-Energy Kink Observed In The Electron Dispersion Of High-Temperature Cuprate Superconductors, T. Valla, T. E. Kidd, W.-G. Yin, G. D. Gu, Z.-H. Pan, A. V. Fedorov Apr 2007

High-Energy Kink Observed In The Electron Dispersion Of High-Temperature Cuprate Superconductors, T. Valla, T. E. Kidd, W.-G. Yin, G. D. Gu, Z.-H. Pan, A. V. Fedorov

Faculty Publications

Photoemission studies show the presence of a high-energy anomaly in the observed band dispersion for two families of cuprate superconductors, Bi2Sr2CaCu2O8+δ and La2-xBaxCuO4. The anomaly, which occurs at a binding energy of approximately 340 meV, is found to be anisotropic and relatively weakly doping dependent. Scattering from short range or nearest neighbor spin excitations is found to supply an adequate description of the observed phenomena.

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Steganography Anomaly Detection Using Simple One Class Classification, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian Apr 2007

Steganography Anomaly Detection Using Simple One Class Classification, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian

Faculty Publications

No abstract provided.

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Photoproduction Of Events With Rapidity Gaps Between Jets At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli Apr 2007

Photoproduction Of Events With Rapidity Gaps Between Jets At Hera, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli

Faculty Publications

The photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 39 pb -1. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value ETCUT. The data show a clear excess over the predictions of standard photoproduction models. This is interpreted as evidence for a strongly interacting exchange of a color-singlet object. Monte Carlo models which include such a …

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Multi-Class Classification Averaging Fusion For Detecting Steganography, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian Apr 2007

Multi-Class Classification Averaging Fusion For Detecting Steganography, Benjamin M. Rodriguez, Gilbert L. Peterson, Sos S. Agaian

Faculty Publications

Multiple classifier fusion has the capability of increasing classification accuracy over individual classifier systems. This paper focuses on the development of a multi-class classification fusion based on weighted averaging of posterior class probabilities. This fusion system is applied to the steganography fingerprint domain, in which the classifier identifies the statistical patterns in an image which distinguish one steganography algorithm from another. Specifically we focus on algorithms in which jpeg images provide the cover in order to communicate covertly. The embedding methods targeted are F5, JSteg, Model Based, OutGuess, and StegHide. The developed multi-class steganalvsis system consists of three levels: (1) …

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Measurement Of Open Beauty Production At Hera In The D *Μ Final State, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli Apr 2007

Measurement Of Open Beauty Production At Hera In The D *Μ Final State, S. Chekanov, M. Derrick, S. Magill, S. Miglioranzi, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, 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, L. Rinaldi, G. Sartorelli

Faculty Publications

The production of beauty quarks with a D*± and a muon in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb-1. Low transverse-momentum thresholds for the muon and D* meson allow for a measurement of beauty production closer to the production threshold than previous measurements. The beauty signal was extracted using the charge correlations and angular distributions of the muon with respect to the D* meson. Cross sections for photoproduction and deep inelastic scattering are somewhat higher than, but compatible with, next-to-leading-order QCD predictions, and compatible with other measurements. © …

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The Niemann-Pick Type C2 Protein Loads Isoglobotrihexosylceramide Onto Cd1d Molecules And Contributes To The Thymic Selection Of Nkt Cells, Paul B. Savage, Nicolas Schrantz, Yuval Sagiv, Yang Liu, Albert Bendelac, Luc Teyton Mar 2007

The Niemann-Pick Type C2 Protein Loads Isoglobotrihexosylceramide Onto Cd1d Molecules And Contributes To The Thymic Selection Of Nkt Cells, Paul B. Savage, Nicolas Schrantz, Yuval Sagiv, Yang Liu, Albert Bendelac, Luc Teyton

Faculty Publications

The Niemann-Pick type C2 (NPC2) protein is a small, soluble, lysosomal protein important for cholesterol and sphingolipid transport in the lysosome. The immunological phenotype of NPC2-deficient mice was limited to an impaired thymic selection of Valpha 14 natural killer T cells (NKT cells) and a subsequent reduction of NKT cells in the periphery. The remaining NKT cells failed to produce measurable quantities of interferon-gamma in vivo and in vitro after activation with alpha-galactosylceramide. In addition, thymocytes and splenocytes from NPC2-deficient mice were poor presenters of endogenous and exogenous lipids to CD1d-restricted Valpha 14 hybridoma cells. Importantly, we determined that similar …

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Split Quaterionic Representation Of Sdym (Su(1,1) Instantons In S2- × S2+, Sungwook Lee, Khin Maung Maung Mar 2007

Split Quaterionic Representation Of Sdym (Su(1,1) Instantons In S2- × S2+, Sungwook Lee, Khin Maung Maung

Faculty Publications

Using split‐quaternions, we find explicit SDYM SU(1,1) instanton solutions in S2- × S2+ which is the conformal compactification of the semi‐Euclidean 4‐spacetime R2+2 of split signature (-,-,+,+). It is also shows that SDYM and ASDYM fields in S2- × S2+ can be described as simple split-quaternionic 2-forms.

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Particulate Organic Carbon Fluxes Along Upwelling‐Dominated Continental Margins: Rates And Mechanisms, Robert Thunell, Claudia R. Benitez-Nelson, Ramon Varela, Yrene Astor, Frank Muller‐Karger Mar 2007

Particulate Organic Carbon Fluxes Along Upwelling‐Dominated Continental Margins: Rates And Mechanisms, Robert Thunell, Claudia R. Benitez-Nelson, Ramon Varela, Yrene Astor, Frank Muller‐Karger

Faculty Publications

[1] Time series sediment trap samples were used to examine the rates and mechanisms of particulate organic carbon (POC) flux at three continental margin locations, Santa Barbara Basin, Cariaco Basin, and Guaymas Basin, marked by seasonal upwelling and high primary production. The mean POC flux in Santa Barbara Basin (0.096 g m−2 d−1) is nearly twice that of Cariaco Basin and 4 times higher than that in Guaymas Basin, with all three sites having POC fluxes significantly higher than the open ocean average (0.007 g m−2 d−1). In Cariaco Basin, the only site with available primary production numbers, there is …

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Submarine Volcanic Morphology Of The Western Galapagos Based On Em300 Bathymetry And Mr1 Side-Scan Sonar, Jennifer B. Glass, D J. Fornari, Hillary F. Hall, Allison A. Cougan, Heidi A. Berkenbosch, Mark L. Holmes, Scott M. White, Giorgio De La Torre Mar 2007

Submarine Volcanic Morphology Of The Western Galapagos Based On Em300 Bathymetry And Mr1 Side-Scan Sonar, Jennifer B. Glass, D J. Fornari, Hillary F. Hall, Allison A. Cougan, Heidi A. Berkenbosch, Mark L. Holmes, Scott M. White, Giorgio De La Torre

Faculty Publications

A compilation of high-resolution EM300 multibeam bathymetric and existing MR1 side-scan sonar data was used to investigate the volcanic morphology of the flanks of the western Galapagos Islands. The data portray an assortment of constructional volcanic features on the shallow to deep submarine flanks of Fernandina, Isabela, and Santiago Islands, including rift zones and groups of cones that are considered to be the primary elements in constructing the archipelagic apron. Ten submarine rift zones were mapped, ranging in length from 5 to 20 km, comparable in length to western Canary Island rift zones but significantly shorter than Hawaiian submarine rift …

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Ria: An Rf Interference Avoidance Algorithm For Heterogeneous Wireless Networks, Daniel P. Delorey, Qiuyi Duan, Charles D. Knutson, Manoj Pandey, Lei Wang, Ryan W. Woodings, Daniel Zappala Mar 2007

Ria: An Rf Interference Avoidance Algorithm For Heterogeneous Wireless Networks, Daniel P. Delorey, Qiuyi Duan, Charles D. Knutson, Manoj Pandey, Lei Wang, Ryan W. Woodings, Daniel Zappala

Faculty Publications

Devices with multiple wireless interfaces are becoming increasingly popular. We envision that these devices will become the building block for future mesh networks, providing seamless connectivity across a range of heterogeneous devices. Although these devices typically implement frequency sharing, using either Direct Sequence Spread Spectrum (DSSS) or Frequency Hopping Spread Spectrum (FHSS), they may still interfere with one another. In this paper we provide a novel Radio Interference Avoidance (RIA) algorithm that solves the problem of interference between IEEE 802.11 and Bluetooth. We then extend this algorithm to other types of DSSS and FHSS combinations. Though the algorithm is limited …

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Grating Lobe Reduction In Transducer Arrays Through Structural Filtering Of Supercritical Plates, Brian E. Anderson, Stephen A. Hambric, Jack W. Hughes Mar 2007

Grating Lobe Reduction In Transducer Arrays Through Structural Filtering Of Supercritical Plates, Brian E. Anderson, Stephen A. Hambric, Jack W. Hughes

Faculty Publications

The effect of placing a structural acoustic filter between water and the transducer elements of an array to help reduce undesirable grating lobes is investigated. A supercritical plate is mounted to transducer elements with a thin decoupling polyurethane layer between the transducers and the plate. The plate acts as a radiation/incidence angle filter to pass energy at angles near normal incidence, but suppress energy at large incidence angles. Grating lobe reduction is achieved at the expense of limiting the available steering of the main lobe. Within this steer angle limitation, the main lobe can be steered as normal while the …

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Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal Mar 2007

Investigation Of Cdznte Crystal Defects Using Scanning Probe Microscopy, Goutam Koley, J. Liu, K. C. Mandal

Faculty Publications

No abstract provided.

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Precision In Imaging Multivariate Optical Computing, Michael N. Simcock, Michael L. Myrick Mar 2007

Precision In Imaging Multivariate Optical Computing, Michael N. Simcock, Michael L. Myrick

Faculty Publications

Multivariate optical computing (MOC) is a method of performing chemical analysis using a multilayer thin-film structure known as a multivariate optical element (MOE). Recently we have been advancing MOC for imaging problems by using an imaging MOE (IMOE) in a normal-incidence geometry and employing normalization by the 1-norm. There are several important differences between the previously described 45° and the normal-incidence imaging, one of which is the measurement precision due to photon counting. We compare this precision to 45° MOC. We also discuss how MOE models with similar values of standard errors of calibration and prediction and similar gain values …

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Bounds And Conditions: A Kolob In Our Solar System?, David D. Allred Mar 2007

Bounds And Conditions: A Kolob In Our Solar System?, David D. Allred

Faculty Publications

In 2003, Dialogue ran adjacent essays by two scientists, David Tolman and David Allred. The two Davids had been students together at Princeton, attending the same student ward. Decades after Princeton, Tolman had left Mormonism and Allred had stayed. Their essays are a fascinating juxtaposition. In the course of his piece, David Allred ventured for a few paragraphs into a discussion of the planet Jupiter and its role as a governor and protector in our solar system—a type of Kolob. Although the other author dismissed the topic as “fanciful physics,” my own interest was piqued. I asked Dr. Allred, who …

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Trisodium Dicalcium Bismuth Hexaoxide, Irina V. Puzdrjakova, Rene B. Macquart, Mark D. Smith, Hans-Conrad Zur Loye Feb 2007

Trisodium Dicalcium Bismuth Hexaoxide, Irina V. Puzdrjakova, Rene B. Macquart, Mark D. Smith, Hans-Conrad Zur Loye

Faculty Publications

Single crystals of the title compound, Na3Ca2BiO6, were grown from a high-temperature reactive flux solution of Na2CO3. Na3Ca2BiO6 crystallizes as an ordered rock-salt structure (space group Fddd), in which the octahedral holes in the oxide array are filled by an ordered 3:2:1 arrangement of Na+, Ca2+ and Bi5+ cations. All atoms except for one O atom lie on special positions; site symmetries are as follows: Bi 222, Ca 2, Na 222 and 2, O 2.

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