678 research outputs found

    A Biased Review of Sociophysics

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    Various aspects of recent sociophysics research are shortly reviewed: Schelling model as an example for lack of interdisciplinary cooperation, opinion dynamics, combat, and citation statistics as an example for strong interdisciplinarity.Comment: 16 pages for J. Stat. Phys. including 2 figures and numerous reference

    Indirect exchange in GaMnAs bilayers via spin-polarized inhomogeneous hole gas: Monte Carlo simulation

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    The magnetic order resulting from an indirect exchange between magnetic moments provided by spin-polarized hole gas in the metallic phase of a GaMnAs double layer structure is studied via Monte Carlo simulation. The coupling mechanism involves a perturbative calculation in second order of the interaction between the magnetic moments and carriers (holes). We take into account a possible polarization of the hole gas due to the existence of an average magnetization in the magnetic layers, establishing, in this way, a self-consistency between the magnetic order and the electronic structure. That interaction leads to an internal ferromagnetic order inside each layer, and a parallel arrangement between their magnetizations, even in the case of thin layers. This fact is analyzed in terms of the inter- and intra-layer interactions.Comment: 17 pages and 14 figure

    Magnetic Field Amplification in Galaxy Clusters and its Simulation

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    We review the present theoretical and numerical understanding of magnetic field amplification in cosmic large-scale structure, on length scales of galaxy clusters and beyond. Structure formation drives compression and turbulence, which amplify tiny magnetic seed fields to the microGauss values that are observed in the intracluster medium. This process is intimately connected to the properties of turbulence and the microphysics of the intra-cluster medium. Additional roles are played by merger induced shocks that sweep through the intra-cluster medium and motions induced by sloshing cool cores. The accurate simulation of magnetic field amplification in clusters still poses a serious challenge for simulations of cosmological structure formation. We review the current literature on cosmological simulations that include magnetic fields and outline theoretical as well as numerical challenges.Comment: 60 pages, 19 Figure

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Raman Spectroscopy of Amino Acid Crystals

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    In this chapter, we investigate the Raman spectra of proteinogenic amino acid crystals. Amino acids are fundamental organic molecules that compose polypeptides (a linear chain of amino acids) and proteins (folded polypeptides with specific functions) found in all living beings. Surprisingly, the number of these basic molecules is not more than 22 (20 of them commonly known as the standard amino acids, plus pyrrolysine and selenocysteine). They are defined as a molecule formed by an NH2 group, a COOH group, a lateral chain (the R group), and a hydrogen atom, all of them connected to a single carbon, the α-carbon. Interestingly, α-amino acids show chirality, i.e., they present different distributions of group of atoms around the α-carbon, being defined as l- and d-form. For amino acids and proteins found in the living beings, the l-form is the dominant form, although some exceptions have been discovered in the last decades. In this chapter, we present the Raman spectra of all standard amino acids and discuss the different kinds of vibrations found, comparing them. As complementary part of the work, we present results on vibrational properties of some amino acids using Raman spectroscopy when subjected to specific conditions, with variation in temperature or pressure. Finally, we present some perspectives as the investigation of purines, a group of molecules associated with the DNA molecule

    Communication: Transient Anion States Of Phenol...(h2o) N (n = 1, 2) Complexes: Search For Microsolvation Signatures

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    We report on the shape resonance spectra of phenol-water clusters, as obtained from elastic electron scattering calculations. Our results, along with virtual orbital analysis, indicate that the well-known indirect mechanism for hydrogen elimination in the gas phase is significantly impacted on by microsolvation, due to the competition between vibronic couplings on the solute and solvent molecules. This fact suggests how relevant the solvation effects could be for the electron-driven damage of biomolecules and the biomass delignification [E. M. de Oliveira et al., Phys. Rev. A 86, 020701(R) (2012)]. We also discuss microsolvation signatures in the differential cross sections that could help to identify the solvated complexes and access the composition of gaseous admixtures of these species. © 2014 AIP Publishing LLC.1415NSF; National Stroke FoundationSanche, L., (2005) Eur. Phys. J. D, 35, p. 367. , For a review, see, 10.1140/epjd/e2005-00206-6Wang, C.-R., Nguyen, J., Lu, Q.-B., (2009) J. Am. Chem. Soc., 131, p. 11320. , 10.1021/ja902675gBaccarelli, I., Bald, I., Gianturco, F.A., Illenberger, E., Kopyra, J., (2011) Phys. Rep., 508, p. 1. , 10.1016/j.physre2011.06.004Bettega, M.H.F., Lima, M.A.P., (2007) J. Chem. Phys., 126, p. 194317. , 10.1063/1.2739514De Oliveira, E.M., Lima, M.A.P., Bettega, M.H.F., Sanchez, S.D.A., Da Costa, R.F., Varella, M.T.D.N., (2010) J. Chem. Phys., 132, p. 204301. , 10.1063/1.3428620Baccarelli, I., Grandi, A., Gianturco, F.A., Lucchese, R.R., Sanna, N., (2006) J. Phys. Chem. B, 110, p. 26240. , 10.1021/jp065872nFabrikant, I.I., Caprasecca, S., Gallup, G.A., Gorfinkiel, J.D., (2012) J. Chem. Phys., 136, p. 184301. , 10.1063/1.4706604Freitas, T.C., Lima, M.A.P., Canuto, S., Bettega, M.H.F., (2009) Phys. Rev. A, 80, p. 062710. , 10.1103/PhysRevA.80.062710Freitas, T.C., Coutinho, K., Varella, M.T.D.N., Lima, M.A.P., Canuto, S., Bettega, M.H.F., (2013) J. Chem. Phys., 138, p. 174307. , 10.1063/1.4803119De Oliveira, E.M., Sanchez, S.D.A., Bettega, M.H.F., Natalense, A.P.P., Lima, M.A.P., Do Varella N, M.T., (2012) Phys. Rev. A, 86, pp. 020701-R. , 10.1103/PhysRevA.86.020701Jordan, K.D., Michejda, J.A., Burrow, P.D., (1976) J. Am. Chem. Soc., 98, p. 7189. , 10.1021/ja00439a014Khatymov, R.V., Muftakhov, M.V., Mazunov, V.A., (2003) Rapid Commun. Mass Spectrom., 17, p. 2327. , 10.1002/rcm.1197Dos Santos, J.S., Da Costa, R.F., Varella, M.T.D.N., (2012) J. Chem. Phys., 136, p. 084307. , 10.1063/1.3687345Bettega, M.H.F., Ferreira, L.G., Lima, M.A.P., (1993) Phys. Rev. A, 47, p. 1111. , 10.1103/PhysRevA.47.1111Da Costa, R.F., Da Paixão, F.J., Lima, M.A.P., (2004) J. Phys. B, 37, pp. L129. , 10.1088/0953-4075/37/6/L03Takatsuka, K., McKoy, V., (1981) Phys. Rev. A, 24, p. 2473. , 10.1103/PhysRevA.24.2473Takatsuka, K., McKoy, V., (1984) Phys. Rev. A, 30, p. 1734. , 10.1103/PhysRevA.30.1734Barreto, R.C., Coutinho, K., Georg, H.C., Canuto, S., (2009) Phys. Chem. Chem. Phys., 11, p. 1388. , 10.1039/b816912h(1998) CRC Handbook of Chemistry and Physics, , 79th ed., edited by D. R. Lide (CRC, Boca Raton)http://dx.doi.org/10.1063/1.4892066Nenner, I., Schulz, G.J., (1975) J. Chem. Phys., 62, p. 1747. , 10.1063/1.430700Winstead, C., McKoy, V., (2007) Phys. Rev. Lett., 98, p. 113201. , 10.1103/PhysRevLett.98.113201Winstead, C., McKoy, V., (2007) Phys. Rev. A, 76, p. 012712. , 10.1103/PhysRevA.76.012712Mažín, Z., Gorfinkiel, J.D., (2011) J. Chem. Phys., 135, p. 144308. , 10.1063/1.3650236Modelli, A., Burrow, P.W., (2004) J. Phys. Chem. A, 108, p. 5721. , 10.1021/jp048759aSchmidt, M.W., Baldridge, K.K., Boatz, J.A., Elbert, S.T., Gordon, M.S., Jensen, J.H., Koseki, S., Montgomery, J.A., (1993) J. Comput. Chem., 14, p. 1347. , 10.1002/jcc.540141112Kossoski, F., Bettega, M.H.F., Varella, M.T.D.N., (2014) J. Chem. Phys., 140, p. 024317. , 10.1063/1.4861589Gallup, G., Burrow, P., Fabrikant, I., (2009) Phys. Rev. A, 79, p. 042701. , 10.1103/PhysRevA.79.042701Gallup, G., Burrow, P., Fabrikant, I., (2009) Phys. Rev. A, 80, p. 046702. , 10.1103/PhysRevA.80.046702Scheer, A.M., Mozejko, P., Gallup, G.A., Burrow, P.D., (2007) J. Chem. Phys., 126, p. 174301. , 10.1063/1.2727460Asmis, K.R., Allan, M., Pyrrole Data in the Gallery of Unpublished EEL Spectra, , http://www.chem.unifr.ch/ma/dir_allan/pyrrole_EELS.pdfHaxton, D.J., McCurdy, C.W., Rescigno, T.N., (2007) Phys. Rev. A, 75, p. 012710. , 10.1103/PhysRevA.75.012710Bode, B.M., Gordon, M.S., (1998) J. Mol. Graphics Modell., 16, p. 133. , 10.1016/S1093-3263(99)00002-9Fuke, K., Kaya, K., (1983) Chem. Phys. Lett., 94, p. 97. , 10.1016/0009-2614(83)87218-

    Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

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    We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

    Biological aspects of the leafminer Liriomyza sativae (Diptera: Agromyzidae) on melon (Cucumis melo L.)

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    A mosca-minadora Liriomyza sativae Blanchard é uma praga importante em cultivos de meloeiro (Cucumis melo L.) no Brasil. No entanto, as suas informações sobre biologia, em meloeiro, são escassas. Portanto, o objetivo deste trabalho foi conhecer alguns aspectos biológicos dessa praga, criada em plantas de meloeiro, em condições de laboratório a 25°C. As informações obtidas mostram que o ciclo biológico de L. sativae é de 15,9±0,04 dias (ovo-adulto), sendo: ovo (2,7±0,01 dias), larva (4,1±0,03 dias) e pupa (9,1±0,03 dias). A razão sexual é de 0,51 e as fêmeas vivem mais tempo (19,3±1,09 dias) que os machos (16,2±0,96 dias). Essas informações podem auxiliar na adoção de medidas de manejo integrado de L. sativae em cultivos de meloeiro e melhorar os sistemas de criação da mosca minadora em laboratório.The leafminer Liriomyza sativae Blanchard is an important insect pest on melon crops in Brazil. However, the information about its biology on melon (Cucumis melo L.) is scarce. Therefore, the aim of this research was to know some biological aspects of this pest, reared on melon plants, under laboratory conditions at 25°C. Our results showed that the biological cycle of L. sativae lasts 15.9±0.04 days (egg-adult), namely: egg (2.7±0.01 days), larva (4.1±0.03 days) and pupa (9.1±0.03 days). The sex ratio is 0.51 and the females live (19.3±1.09 days) longer than males (16.2±0.96 days). These results can help in the integrated management of L. sativae on melon crops and improve the systems for rearing this leafminer in laboratory.Universidade Federal Rural do Semi-Árido (UFERSA) Departamento de Ciências VegetaisUniversidade Estadual Paulista (UNESP) Faculdade de Ciências Agrárias e Veterinárias (FCAV)Universidade Federal de Lavras (UFLA) Departamento de EntomologiaUniversidade Estadual Paulista (UNESP) Faculdade de Ciências Agrárias e Veterinárias (FCAV
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