3,798 research outputs found

    Probing primordial features with the primary CMB

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    CMB photons travel from the last scattering surface, when the primary CMB has been generated, along the surface of the light cone to us. During their travel, they are affected by many secondary effects such as the integrated Sachs-Wolfe effect and CMB lensing. These CMB secondary effects modify the CMB primary power spectrum adding degeneracies and decreasing the sensibility to primordial parameters. The possibility to reconstruct the primary CMB anisotropies will allow us to have a more direct observable to test the physics of the early universe. We propose to study the imprint of features in the primordial power spectrum with the primary CMB after the subtraction of the reconstructed ISW signal from the observed CMB temperature angular power spectrum. We consider the application to features models able to fit two of the large scales anomalies observed in the CMB temperature angular power spectrum: the deficit of power at 2\ell \sim 2 and at 22\ell \sim 22. This method allows to improve significantly the constraints on the features parameters up to 16%16\% for models predicting a suppression of power of the quadrupole and up to 27%27\% for models with features at 22\ell \sim 22, assuming instrumental sensitivity similar to the PlanckPlanck satellite (depending on the goodness of the ISW reconstruction). Furthermore, it gives the opportunity to understand if these anomalies are attributed to early- or late-time physics.Comment: 6 pages, 2 figures, 1 table; Version accepted by Physics of Dark Univers

    L’interprete traduttore nel procedimento penale italiano: quale formazione alla luce delle recenti direttive europee?

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    Il divario esistente tra substrato normativo e applicazione della legge in materia di assistenza linguistica in ambito penale può essere colmato attraverso interventi correttivi a livello normativo e adeguate misure in materia di formazione e di abilitazione di interpreti e traduttori. Solo professionisti formati e ufficialmente abilitati, accanto a una maggior consapevolezza degli operatori del diritto di ciò che significa interpretare e tradurre, possono garantire un’assistenza linguistica qualitativamente appropriata

    CMB and BAO constraints for an induced gravity dark energy model with a quartic potential

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    We study the predictions for structure formation in an induced gravity dark energy model with a quartic potential. By developing a dedicated Einstein-Boltzmann code, we study self-consistently the dynamics of homogeneous cosmology and of linear perturbations without using any parametrization. By evolving linear perturbations with initial conditions in the radiation era, we accurately recover the quasi-static analytic approximation in the matter dominated era. We use Planck 2013 data and a compilation of baryonic acoustic oscillation (BAO) data to constrain the coupling γ\gamma to the Ricci curvature and the other cosmological parameters. By connecting the gravitational constant in the Einstein equation to the one measured in a Cavendish-like experiment, we find γ<0.0012\gamma < 0.0012 at 95% CL with Planck 2013 and BAO data. This is the tightest cosmological constraint on γ\gamma and on the corresponding derived post-Newtonian parameters. Because of a degeneracy between γ\gamma and the Hubble constant H0H_0, we show how larger values for γ\gamma are allowed, but not preferred at a significant statistical level, when local measurements of H0H_0 are combined in the analysis with Planck 2013 data.Comment: 13 pages, 7 figure

    Cosmological constraints on induced gravity dark energy models

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    We study induced gravity dark energy models coupled with a simple monomial potential σn\propto \sigma^n and a positive exponent nn. These simple potentials lead to viable dark energy models with a weak dependence on the exponent, which characterizes the accelerated expansion of the cosmological model in the asymptotic attractor, when ordinary matter becomes negligible. We use recent cosmological data to constrain the coupling γ\gamma to the Ricci curvature, under the assumptions that the scalar field starts at rest deep in the radiation era and that the gravitational constant in the Einstein equations is compatible with the one measured in a Cavendish-like experiment. By using PlanckPlanck 2015 data only, we obtain the 95 % CL bound γ<0.0017\gamma < 0.0017 for n=4n=4, which is further tightened to γ<0.00075\gamma < 0.00075 by adding Baryonic Acoustic Oscillations (BAO) data. This latter bound improves by 30\sim 30 % the limit obtained with the PlanckPlanck 2013 data and the same compilation of BAO data. We discuss the dependence of the γ\gamma and G˙N/GN(z=0)\dot G_N/G_N (z=0) on nn.Comment: 16 pages, 10 figure

    Tactile-STAR: A Novel Tactile STimulator And Recorder System for Evaluating and Improving Tactile Perception

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    Many neurological diseases impair the motor and somatosensory systems. While several different technologies are used in clinical practice to assess and improve motor functions, somatosensation is evaluated subjectively with qualitative clinical scales. Treatment of somatosensory deficits has received limited attention. To bridge the gap between the assessment and training of motor vs. somatosensory abilities, we designed, developed, and tested a novel, low-cost, two-component (bimanual) mechatronic system targeting tactile somatosensation: the Tactile-STAR—a tactile stimulator and recorder. The stimulator is an actuated pantograph structure driven by two servomotors, with an end-effector covered by a rubber material that can apply two different types of skin stimulation: brush and stretch. The stimulator has a modular design, and can be used to test the tactile perception in different parts of the body such as the hand, arm, leg, big toe, etc. The recorder is a passive pantograph that can measure hand motion using two potentiometers. The recorder can serve multiple purposes: participants can move its handle to match the direction and amplitude of the tactile stimulator, or they can use it as a master manipulator to control the tactile stimulator as a slave. Our ultimate goal is to assess and affect tactile acuity and somatosensory deficits. To demonstrate the feasibility of our novel system, we tested the Tactile-STAR with 16 healthy individuals and with three stroke survivors using the skin-brush stimulation. We verified that the system enables the mapping of tactile perception on the hand in both populations. We also tested the extent to which 30 min of training in healthy individuals led to an improvement of tactile perception. The results provide a first demonstration of the ability of this new system to characterize tactile perception in healthy individuals, as well as a quantification of the magnitude and pattern of tactile impairment in a small cohort of stroke survivors. The finding that short-term training with Tactile-STARcan improve the acuity of tactile perception in healthy individuals suggests that Tactile-STAR may have utility as a therapeutic intervention for somatosensory deficits
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