1,400 research outputs found
Small Angle Polarization in High Energy P--P Scattering Through Nonperturbative Chiral Symmetry Breaking
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 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
We implement the transition from dark matter to dark energy in k-essence
cosmologies for a very large set of kinetic functions , 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
We assess the capabilities of magnetic Resonant Inelastic X-ray Scattering
(RIXS) at the O 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 edge RIXS spectra. These are a dominant
peak around 450 meV, the almost complete absence of dispersion both with
and polarization and the almost constant intensity vs. the transferred
momentum with polarization. This behavior is quite different from Cu
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 edge that we present. The Cu bimagnon spectra and those at Cu
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 RIXS in the study of magnetic excitations in
cuprates near the center of the BZ
Internal space structure generalization of the quintom cosmological scenario
We introduce the Lagrangian for a multi-scalar field configuration in a
-dimensional internal space endowed with a constant metric 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 CDM 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 exceeds the dimension of the internal
phantom sector . For 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
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
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
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
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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