1,400 research outputs found

    Small Angle Polarization in High Energy P--P Scattering Through Nonperturbative Chiral Symmetry Breaking

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    We show that a large anomalous contribution due to nonperturbative instanton-like gluonic field configurations to the axial charge of the proton implies high-energy spin effects in p−pp-p elastic scattering. This is the same mechanism which is responsible for anomalous baryon number violation at high energy in the standard model. We compute the proton polarization due to these effects and we show that it is proportional to the center-of-mass scattering angle with a universal (energy-independent) slope of order unity.Comment: (13 pages, 2 figures

    Dark matter to dark energy transition in k-essence cosmologies

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    We implement the transition from dark matter to dark energy in k-essence cosmologies for a very large set of kinetic functions FF, in a way alternative to recent proposals which use generalized Chaplygin gas and transient models. Here we require that the pressure admits a power-law expansion around some value of the kinetic energy where the pressure vanishes. In addition, for suitable values of the parameters of the model, the speed of sound of the dark matter will be low. We first present the discussion in fairly general terms, and later consider for illustration two examples.Comment: 5 pages, revte

    Bimagnon studies in cuprates with Resonant Inelastic X-ray Scattering at the O K edge. I - An assessment on La2CuO4 and a comparison with the excitation at Cu L3 and Cu K edges

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    We assess the capabilities of magnetic Resonant Inelastic X-ray Scattering (RIXS) at the O KK edge in undoped cuprates by taking La_{2}CuO_{4} as a benchmark case, based on a series of RIXS measurements that we present here. By combining the experimental results with basic theory we point out the fingerprints of bimagnon in the O KK edge RIXS spectra. These are a dominant peak around 450 meV, the almost complete absence of dispersion both with π\pi and σ\sigma polarization and the almost constant intensity vs. the transferred momentum with σ\sigma polarization. This behavior is quite different from Cu L3L_3 edge RIXS giving a strongly dispersing bimagnon tending to zero at the center of the Brillouin zone. This is clearly shown by RIXS measurements at the Cu L3L_3 edge that we present. The Cu L3L_3 bimagnon spectra and those at Cu KK edge - both from the literature and from our data - however, have the same shape. These similarities and differences are understood in terms of different sampling of the bimagnon continuum. This panorama points out the unique possibilities offered by O KK RIXS in the study of magnetic excitations in cuprates near the center of the BZ

    Internal space structure generalization of the quintom cosmological scenario

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    We introduce the Lagrangian for a multi-scalar field configuration in a NN-dimensional internal space endowed with a constant metric QikQ_{ik} and generalize the quintom cosmological scenario. We find the energy momentum tensor of the model and show that the set of dual transformations, that preserve the form of the Einstein equations in the Friedmann-Robertson-Walker (FRW) cosmology, is enlarged. We show that the stability of the power law solutions leads to an exponential potential which is invariant under linear transformations in the internal space. Moreover, we obtain the general exact solution of the Einstein-Klein-Gordon equations for that potential. There exist solutions that cross the phantom divide and solutions that blow up at a finite time, exhibiting a superaccelerated behavior and ending in a big rip. We show that the quintom model with a separable potential can be identified with a mixture of several fluids. This framework includes the Λ\LambdaCDM model, a bouncing model, and a setting sourced by a cosmic string network plus a cosmological constant. The we concentrate on the case where the dimension of the internal quintessence sector NqN_{q} exceeds the dimension of the internal phantom sector NphN_{ph}. For (Nq,Nph)=(2,1)(N_q,N_{ph})=(2,1) the dark energy density derived from the 3-scalar field crosses the phantom divide and its negative component plays the role of the negative part of a classical Dirac Field.Comment: 10 pages, 2 figure

    Physics at the front-end of a neutrino factory: a quantitative appraisal

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    We present a quantitative appraisal of the physics potential for neutrino experiments at the front-end of a muon storage ring. We estimate the forseeable accuracy in the determination of several interesting observables, and explore the consequences of these measurements. We discuss the extraction of individual quark and antiquark densities from polarized and unpolarized deep-inelastic scattering. In particular we study the implications for the undertanding of the nucleon spin structure. We assess the determination of alpha_s from scaling violation of structure functions, and from sum rules, and the determination of sin^2(theta_W) from elastic nu-e and deep-inelastic nu-p scattering. We then consider the production of charmed hadrons, and the measurement of their absolute branching ratios. We study the polarization of Lambda baryons produced in the current and target fragmentation regions. Finally, we discuss the sensitivity to physics beyond the Standard Model.Comment: 73+1 pages, 33 figs. Report of the nuDIS Working Group for the ECFA-CERN Neutrino-Factory study, M.L. Mangano (convener

    Proton therapy and src family kinase inhibitor combined treatments on U87 human glioblastoma multiforme cell line

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    Glioblastoma Multiforme (GBM) is the most common of malignant gliomas in adults with an exiguous life expectancy. Standard treatments are not curative and the resistance to both chemotherapy and conventional radiotherapy (RT) plans is the main cause of GBM care failures. Proton therapy (PT) shows a ballistic precision and a higher dose conformity than conventional RT. In this study we investigated the radiosensitive effects of a new targeted compound, SRC inhibitor, named Si306, in combination with PT on the U87 glioblastoma cell line. Clonogenic survival assay, dose modifying factor calculation and linear-quadratic model were performed to evaluate radiosensitizing effects mediated by combination of the Si306 with PT. Gene expression profiling by microarray was also conducted after PT treatments alone or combined, to identify gene signatures as biomarkers of response to treatments. Our results indicate that the Si306 compound exhibits a radiosensitizing action on the U87 cells causing a synergic cytotoxic effect with PT. In addition, microarray data confirm the SRC role as the main Si306 target and highlights new genes modulated by the combined action of Si306 and PT. We suggest, the Si306 as a new candidate to treat GBM in combination with PT, overcoming resistance to conventional treatments

    Operator Algebra in Chern-Simons Theory on a Torus

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    We consider Chern-Simons gauge theory on a torus with both nonrelativistic and relativistic matter. It is shown that the Hamiltonian and two total momenta commute among themselves only in the physical Hilbert space. We also discuss relations among degenerate physical states, degenerate vacua, and the existence of multicomponent Schrodinger wavefunctions.Comment: 12 pages, TPI-Minn-92/41-T, UMN-TH-1105/9

    Support management in schizophrenia: a systematic review of current literature

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    Maurizio Pompili,1 Franco Montebovi,1 Alberto Forte,1 Mario Palermo,1 Henry Stefani,1 Ludovica Telesforo,1 Sandra Campi,1 Gloria Giordano,1 Lucia Longo,1 Dorian A Lamis,2 Gianluca Serafini,1 Paolo Girardi11Department of Neurosciences, Mental Health and Sensory Functions, Suicide Prevention Center, Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy; 2Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USABackground: Schizophrenia is generally considered a chronic disorder characterized by psychotic symptoms and relatively stable neurocognitive and interpersonal deficits. Antipsychotic medication has proven beneficial in reducing psychotic symptoms, but is often not enough to treat cognitive or functional impairments. Residual cognitive impairments are barriers to a patient's full recovery from schizophrenia. Rehabilitation is an alternative and important approach which may be useful, and encompasses a variety of treatments including social skills training and psychoeducational and cognitive behavioral treatments.Objective: To investigate the efficacy of psychosocial treatments in schizophrenia, evaluating its effects in the short and long term, comparing psychosocial treatments with pharmacotherapy, and assessing the effects of treatment and the main indications for use in patients with schizophrenia.Methods: A careful MEDLINE®, Excerpta Medica, PsycLIT®, PsycINFO®, and Index Medicus search was performed to identify all papers and book chapters in English for the period 1970–2012.Results: Findings from the studies included in this qualitative analysis suggest that social skills therapy, cognitive behavioral therapy, family intervention therapy, cognitive remediation therapy, and other nonpharmacological therapeutic strategies may be beneficial for patients with significant functional and symptomatic impairments.Conclusion: Schizophrenic patients treated with nonpharmacological techniques have more rapid remission and relapse less frequently than patients treated only pharmacologically.Keywords: schizophrenia, support management, nonpharmacological treatment, cognitive behavioral therap
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