11,720 research outputs found

    Acquisition of ownership illusion with self-disownership in neurological patients

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    The multisensory regions in frontoparietal cortices play a crucial role in the sense of body and self. Disrupting this sense may lead to a feeling of disembodiment, or more generally, a sense of disownership. Experimentally, this altered consciousness disappears during illusory own-body perceptions, increasing the intensity of perceived ownership for an external virtual limb. In many clinical conditions, particularly in individuals with a discontinuous or absent sense of bodily awareness, the brain may effortlessly create a convincing feeling of body ownership over a surrogate body or body part. The immediate visual input dominates the current bodily state and induces rapid plastic adaptation that reconfigures the dynamics of bodily representation, allowing the brain to acquire an alternative sense of body and self. Investigating strategies to deconstruct the lack of a normal sense of bodily ownership, especially after a neurological injury, may aid the selection of appropriate clinical treatment

    An approach to harmonic load- and source-pull measurements for high-efficiency PA design

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    High-efficiency power-amplifier design requires numerous efforts to investigate both input and output harmonic terminations effects. A simplified theoretical approach to clarify the relevance of such terminations is presented here, and design criteria to improve efficiency for high-frequency applications are briefly discussed. An advanced active load/source-pull test-bench has been used to validate theoretical harmonic tuning techniques, characterizing an active device. The adopted optimization strategy is presented, together with measured results obtained with a medium-power 1-mm MESFET at 1 GHz. Input second harmonic impedances effects are stressed, showing a drain efficiency spread between 37%-49% for a fixed input power level, corresponding to 1-dB compression. Finally, as predicted by the presented theory, after input second harmonic tuning, further improvements are obtained, increasing fundamental output load resistive part, demonstrating an additional drain efficiency enhancement, which reaches a level of 55% at 1-dB compression

    On the rapidity dependence of the average transverse momentum in hadronic collisions

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    The energy and rapidity dependence of the average transverse momentum ⟨pT⟩\langle p_T \rangle in pppp and pApA collisions at RHIC and LHC energies are estimated using the Colour Glass Condensate (CGC) formalism. We update previous predictions for the pTp_T - spectra using the hybrid formalism of the CGC approach and two phenomenological models for the dipole - target scattering amplitude. We demonstrate that these models are able to describe the RHIC and LHC data for the hadron production in pppp, dAudAu and pPbpPb collisions at pT≤20p_T \le 20 GeV. Moreover, we present our predictions for ⟨pT⟩\langle p_T \rangle and demonstrate that the ratio ⟨pT(y)⟩/⟨pT(y=0)⟩\langle p_{T}(y)\rangle / \langle p_{T}(y = 0)\rangle decreases with the rapidity and has a behaviour similar to that predicted by hydrodynamical calculations.Comment: 11 pages, 7 figures; revised version: new results for the average transverse momentum at partonic level added in fig. 4; Results and Discussion section has been improved and enlarge

    Testing the running coupling kTk_{T}-factorization formula for the inclusive gluon production

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    The inclusive gluon production at midrapidities is described in the Color Glass Condensate formalism using the kTk_T - factorization formula, which was derived at fixed coupling constant considering the scattering of a dilute system of partons with a dense one. Recent analysis demonstrated that this approach provides a satisfactory description of the experimental data for the inclusive hadron production in pp/pA/AApp/pA/AA collisions. However, these studies are based on the fixed coupling kTk_T - factorization formula, which does not take into account the running coupling corrections, which are important to set the scales present in the cross section. In this paper we consider the running coupling corrected kTk_T - factorization formula conjectured some years ago and investigate the impact of the running coupling corrections on the observables. In particular, the pseudorapidity distributions and charged hadrons multiplicity are calculated considering pppp, dAu/pPbdAu/pPb and AuAu/PbPbAuAu/PbPb collisions at RHIC and LHC energies. We compare the corrected running coupling predictions with those obtained using the original kTk_T - factorization assuming a fixed coupling or a prescription for the inclusion of the running of the coupling. Considering the Kharzeev - Levin - Nardi unintegrated gluon distribution and a simplified model for the nuclear geometry, we demonstrate that the distinct predictions are similar for the pseudorapidity distributions in pp/pA/AApp/pA/AA collisions and for the charged hadrons multiplicity in pp/pApp/pA collisions. On the other hand, the running coupling corrected kTk_T - factorization formula predicts a smoother energy dependence for dN/dηdN/d\eta in AAAA collisions.Comment: 9 pages and 4 figure

    Solving the excitation and chemical abundances in shocks: the case of HH1

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    We present deep spectroscopic (3600 - 24700 A) X-shooter observations of the bright Herbig-Haro object HH1, one of the best laboratories to study the chemical and physical modifications caused by protostellar shocks on the natal cloud. We observe atomic fine structure lines, HI, and He, recombination lines and H_2, ro-vibrational lines (more than 500 detections in total). Line emission was analyzed by means of Non Local Thermal Equilibiurm codes to derive the electron temperature and density, and, for the first time, we are able to accurately probe different physical regimes behind a dissociative shock. We find a temperature stratification in the range 4000 - 80000 K, and a significant correlation between temperature and ionization energy. Two density regimes are identified for the ionized gas, a more tenuous, spatially broad component (density about 10^3 cm^-3), and a more compact component (density > 10^5 cm^-3) likely associated with the hottest gas. A further neutral component is also evidenced, having temperature lass than 10000 K and density > 10^4 cm^-3. The gas fractional ionization was estimated solving the ionization equilibrium equations of atoms detected in different ionization stages. We find that neutral and fully ionized regions co-exist inside the shock. Also, indications in favor of at least partially dissociative shock as the main mechanism for molecular excitation are derived. Chemical abundances are estimated for the majority of the detected species. On average, abundances of non-refractory/refractory elements are lower than solar of about 0.15/0.5 dex. This testifies the presence of dust inside the medium, with a depletion factor of Iron of about 40%.Comment: Accepted by The Astrophysical Journa

    Neural-Based Nonlinear Device Models for Intermodulation Analysis

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    A new procedure to learn a nonlinear model together with its derivative parameters using a composite neural network is presented.So far neural networks have never been used to extract large-signal device model accounting for distortion parameters.Applying this method to FET devices leads to nonlinear models for current- voltage functions which allow improved prediction of weak and mildly device nonlinearities in the whole bias region. The resulting models have demonstrated to be suitable for both small-signal and large-signal analyses,including intermodulation distortion prediction

    Approaches to prevention of gynecological malignancies

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    Gynecological malignancies represent one of the prevalent diseases in the female sex and prevention is essential to limit their incidence and mortality. Nowadays, not all malignancies benefit from adequate screening methods for this reason new biomarkers and methods are being developed to undertake timely and effective therapies

    IR diagnostics of embedded jets: velocity resolved observations of the HH34 and HH1 jets

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    We present VLT-ISAAC medium resolution spectroscopy of the HH34 and HH1 jets. Our aim is to derive the kinematics and the physical parameters and to study how they vary with jet velocity. We use several important diagnostic lines such as [FeII] 1.644um, 1.600um and H2 2.122um. In the inner jet region of HH34 we find that both the atomic and molecular gas present two components at high and low velocity. The [FeII] LVC in HH34 is detected up to large distances from the source (>1000 AU), at variance with TTauri jets. In H2 2.122um, the LVC and HVC are spatially separated. We detect, for the first time, the fainter red-shifted counterpart down to the central source. In HH1, we trace the jet down to ~1" from the VLA1 driving source: the kinematics of this inner region is again characterised by the presence of two velocity components, one blue-shifted and one red-shifted with respect to the source LSR velocity. In the inner HH34 jet region, ne increases with decreasing velocity. Up to ~10" from the driving source, and along the whole HH1 jet an opposite behaviour is observed instead, with ne increasing with velocity. In both jets the mass flux is carried mainly by the high-velocity gas. A comparison between the position velocity diagrams and derived electron densities with models for MHD jet launching mechanisms has been performed for HH34. While the kinematical characteristics of the line emission at the jet base can be, at least qualitatively, reproduced by both X-winds and disc-wind models, none of these models can explain the extent of the LVC and the dependence of electron density with velocity that we observe. It is possible that the LVC in HH34 represents gas not directly ejected in the jet but instead denser ambient gas entrained by the high velocity collimated jet.Comment: A&A accepte
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