1,167 research outputs found

    Unified Octonionic Representation of the 10-13 Dimensional Clifford Algebra

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    We give a one dimensional octonionic representation of the different Clifford algebra Cliff(5,5)\sim Cliff(9,1), Cliff(6,6)\sim Cliff(10,2) and lastly Cliff(7,6)\sim Cliff(10,3) which can be given by (8x8) real matrices taking into account some suitable manipulation rules.Comment: RevTex file, 19 pages, to be published in Int. J. of Mod. Phys.

    Optical Conductivity of a Two-Dimensional Electron Liquid with Spin-Orbit Interaction

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    The interplay of electron-electron interactions and spin-orbit coupling leads to a new contribution to the homogeneous optical conductivity of the electron liquid. The latter is known to be insensitive to many-body effects for a conventional electron system with parabolic dispersion. The parabolic spectrum has its origin in the Galilean invariance which is broken by spin-orbit coupling. This opens up a possibility for the optical conductivity to probe electron-electron interactions. We analyze the interplay of interactions and spin-orbit coupling and obtain optical conductivity beyond RPA.Comment: 5 pages, 3 figures; final version, fig. 3 added, minor change

    Collaborative Lubricating Oil Study on Emissions: November 28, 2006 - March 31, 2011

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    The Collaborative Lubricating Oil Study on Emissions (CLOSE) project was a pilot investigation of how fuels and crankcase lubricants contribute to the formation of particulate matter (PM) and semi-volatile organic compounds (SVOC) in vehicle exhaust. As limited vehicles were tested, results are not representative of the whole on-road fleet. Long-term effects were not investigated. Pairs of vehicles (one normal PM emitting, one high-PM emitting) from four categories were selected: light-duty (LD) gasoline cars, medium-duty (MD) diesel trucks, heavy-duty (HD) natural-gas-fueled buses, and HD diesel buses. HD vehicles procured did not exhibit higher PM emissions, and thus were labeled high mileage (HM). Fuels evaluated were non-ethanol gasoline (E0), 10 percent ethanol (E10), conventional low-sulfur TxLED diesel, 20% biodiesel (B20), and natural gas. Temperature effects (20 degrees F, 72 degrees F) were evaluated on LD and MD vehicles. Lubricating oil vintage effects (fresh and aged) were evaluated on all vehicles. LD and MD vehicles were operated on a dynamometer over the California Unified Driving Cycle, while HD vehicles followed the Heavy Duty Urban Dynamometer Driving Schedule. Regulated and unregulated emissions were measured. Chemical markers from the unregulated emissions measurements and a tracer were utilized to estimate the lubricant contribution to PM

    Some Features on Entropy Squeezing for Two-Level System with a New Nonlinear Coherent State

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    Abstract Entropy squeezing is an important feature in performing different tasks in quantum information processing such as quantum cryptography and superdense coding. These quantum information tasks depend on finding the states in which squeezing can be created. In this article, a new feature on entropy squeezing for a two level system with a class of nonlinear coherent state (NCS) is observed. An interesting result on the comparison between the coherent state (CS) and NCS is explored. The influence of the Lamb-Dick parameter in both absence and presence of the Kerr medium is examined. A rich feature of entropy squeezing in the case of NCS, which is observed to describe the motion of the trapped ion, has been obtained

    Refractive Errors among Primary Schools Children in Assiut District, Egypt

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    BACKGROUND: Uncorrected refractive errors are a public health problem especially among school children. It has a direct effect on learning and academic performance. AIMS OF THE STUDY: This study aims to assess the refractive errors among a representative sample of school children under ten in Assiut City, Egypt and to manage the discovered cases early. SUBJECTS AND METHODS: Descriptive cross sectional study design was used. The students of primary schools in the first, second and third grades under ten years old were the focus of the study and they were selected by stratified random sampling technique.  The calculated sample size was 196. Two tools were used in the study; the first one was a self administered questionnaire to collect sociodemographic data as child age, birth order, father's and mother's education and occupation, family history of wearing glasses, watching TV or using computer etc. The second tool was the eye examination by a Portable Auto-refractometer which has the advantages of accuracy, easy examination, being movable everywhere and provide printable eye status report. An eye examination record was used to register data about student's name, age. Data collection started from the first of March 2012 until the end of April 2012. Data were analyzed using SPSS soft program version 16. RESULTS: 241 students (107 males and 134 females) participated in the study but 142 only agreed to perform eye examination with 59% response rate. Ninety-five children (66.9%) had a significant refractive error of ±0.50 or worse in one or both eyes. CONCLUSION AND RECOMMENDATIONS: Significant refractive errors occur among primary school children aged 6 to 10 years. Therefore, there is a need to have regular and simple vision testing in primary school children to screen for refractive errors. This will enable to start corrective measures at the early stage and decrease visual disability. Key words: refractive errors- children- primary schools- Egypt

    Inner-sphere oxidation of ternary iminodiacetatochromium(III) complexes involving DL-valine and L-arginine as secondary ligands. Isokinetic relationship for the oxidation of ternary iminodiacetato-chromium(III) complexes by periodate

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    <p>Abstract</p> <p>Background</p> <p>In this paper, the kinetics of oxidation of [Cr<sup>III</sup>(HIDA)(Val)(H<sub>2</sub>O)<sub>2</sub>]<sup>+ </sup>and [Cr<sup>III</sup>(HIDA)(Arg)(H<sub>2</sub>O)<sub>2</sub>]<sup>+ </sup>(HIDA = iminodiacetic acid, Val = DL-valine and Arg = L-arginine) were studied. The choice of ternary complexes was attributed to two considerations. Firstly, in order to study the effect of the secondary ligands DL-valine and L-arginine on the stability of binary complex [Cr<sup>III</sup>(HIDA)(IDA)(H<sub>2</sub>O)] towards oxidation. Secondly, transition metal ternary complexes have received particular focus and have been employed in mapping protein surfaces as probes for biological redox centers and in protein capture for both purification and study.</p> <p>Results</p> <p>The results have shown that the reaction is first order with respect to both [IO<sub>4</sub><sup>-</sup>] and the complex concentration, and the rate increases over the pH range 2.62 – 3.68 in both cases. The experimental rate law is consistent with a mechanism in which both the deprotonated forms of the complexes [Cr<sup>III</sup>(IDA)(Val)(H<sub>2</sub>O)<sub>2</sub>] and [Cr<sup>III</sup>(IDA)(Arg)(H<sub>2</sub>O)<sub>2</sub>] are significantly more reactive than the conjugate acids. The value of the intramolecular electron transfer rate constant for the oxidation of [Cr<sup>III</sup>(HIDA)(Arg)(H<sub>2</sub>O)<sub>2</sub>]<sup>+</sup>, <it>k</it><sub>3 </sub>(1.82 × 10<sup>-3 </sup>s<sup>-1</sup>), is greater than the value of <it>k</it><sub>1 </sub>(1.22 × 10<sup>-3 </sup>s<sup>-1</sup>) for the oxidation of [Cr<sup>III</sup>(HIDA)(Val)(H<sub>2</sub>O)<sub>2</sub>]<sup>+ </sup>at 45.0°C and <it>I </it>= 0.20 mol dm<sup>-3</sup>. It is proposed that electron transfer proceeds through an inner-sphere mechanism <it>via </it>coordination of IO<sub>4</sub><sup>- </sup>to chromium(III).</p> <p>Conclusion</p> <p>The oxidation of [Cr<sup>III</sup>(HIDA)(Val)(H<sub>2</sub>O)<sub>2</sub>]<sup>+ </sup>and [Cr<sup>III</sup>(HIDA)(Arg)(H<sub>2</sub>O)<sub>2</sub>]<sup>+ </sup>by periodate may proceed through an inner-sphere mechanism via two electron transfer giving chromium(VI). The value of the intramolecular electron transfer rate constant for the oxidation of [Cr<sup>III</sup>(HIDA)(Arg)(H<sub>2</sub>O)<sub>2</sub>]<sup>+</sup>, <it>k</it><sub>3</sub>, is greater than the value of <it>k</it><sub>1 </sub>for the oxidation of [Cr<sup>III</sup>(HIDA)(Val)(H<sub>2</sub>O)<sub>2</sub>]<sup>+</sup>. A common mechanism for the oxidation of ternary iminodiacetatochromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH* and ΔS* values for these reactions.</p

    Superfield Description of a Self-Dual Supergravity a la MacDowell-Mansouri

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    Using MacDowell-Mansouri theory, in this work, we investigate a superfield description of the self-dual supergravity a la Ashtekar. We find that in order to reproduce previous results on supersymmetric Ashtekar formalism, it is necessary to properly combine the supersymmetric field-strength in the Lagrangian. We extend our procedure to the case of supersymmetric Ashtekar formalism in eight dimensions.Comment: 19 pages, Latex; section 6 improve

    Towards an Ashtekar formalism in eight dimensions

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    We investigate the possibility of extending the Ashtekar theory to eight dimensions. Our approach relies on two notions: the octonionic structure and the MacDowell-Mansouri formalism generalized to a spacetime of signature 1+7. The key mathematical tool for our construction is the self-dual (antiself-dual) four-rank fully antisymmetric octonionic tensor. Our results may be of particular interest in connection with a possible formulation of M-theory via matroid theory.Comment: 15 pages, Latex, minor changes, to appear in Class. Quantum Gra

    Triggers for displaced decays of long-lived neutral particles in the ATLAS detector

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    A set of three dedicated triggers designed to detect long-lived neutral particles decaying throughout the ATLAS detector to a pair of hadronic jets is described. The efficiencies of the triggers for selecting displaced decays as a function of the decay position are presented for simulated events. The effect of pile-up interactions on the trigger efficiencies and the dependence of the trigger rate on instantaneous luminosity during the 2012 data-taking period at the LHC are discussedFil: Aad, G.. Albert Ludwigs UniversitĂ€t; AlemaniaFil: Abajyan, T.. Universitaet Bonn; AlemaniaFil: Abbott, B.. University of Oklahoma; Estados UnidosFil: Abdallah, J.. Universitat AutĂČnoma de Barcelona; EspañaFil: Abdel Khalek, S.. Universite Paris Sud; FranciaFil: Alconada Verzini, MarĂ­a Josefina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: Alonso, Francisco. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: Anduaga, Xabier Sebastian. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: Dova, Maria Teresa. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: GonzĂĄlez Silva, MarĂ­a Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FĂ­sica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Monticelli, Fernando Gabriel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: Otero y Garzon, Gustavo Javier. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FĂ­sica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Piegaia, Ricardo Nestor. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FĂ­sica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Romeo, Gaston Leonardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de FĂ­sica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Tripiana, Martin Fernando. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FĂ­sica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de FĂ­sica La Plata; ArgentinaFil: Zhuang, X.. Ludwig Maximilians Universitat; AlemaniaFil: Zhuravlov, V.. Max-Planck Institut fĂŒr Physik; AlemaniaFil: Zieminska, D.. Indiana University; Estados UnidosFil: Zimin, N. I.. Joint Institute for Nuclear Research; RusiaFil: Zimmermann, R.. Universitaet Bonn; AlemaniaFil: Zimmermann, S.. Universitaet Bonn; AlemaniaFil: Zimmermann, S.. Albert Ludwigs UniversitĂ€t; AlemaniaFil: Ziolkowski, M.. UniversitĂ€t Siegen; AlemaniaFil: Zitoun, R.. UniversitĂ© de Savoie; FranciaFil: Ćœivković, L.. Columbia University; Estados UnidosFil: Zmouchko, V. V.. State Research Center Institute for High Energy Physics; RusiaFil: Zobernig, G.. University of Wisconsin; Estados UnidosFil: Zoccoli, A.. UniversitĂ  di Bologna; ItaliaFil: zur Nedden, M.. Humboldt University; AlemaniaFil: Zutshi, V.. Northern Illinois University; Estados Unido

    Measurement of the parity-violating asymmetry parameter αb and the helicity amplitudes for the decay Λ0b→J/ψ+Λ0 with the ATLAS detector

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    A measurement of the parity-violating decay asymmetry parameter, αb, and the helicity amplitudes for the decay Λb0→J/ψ(ÎŒ+ÎŒ-)Λ0(pπ-) is reported. The analysis is based on 1400 Λb0 and Λ¯b0 baryons selected in 4.6  fb-1 of proton-proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Λb0 and Λ¯b0 samples under the assumption of CP conservation, the value of αb is measured to be 0.30±0.16(stat)±0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.Fil: F. Monticelli.Fil: Atlas Collaboration
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