5,466 research outputs found

    Correlated Component Analysis for diffuse component separation with error estimation on simulated Planck polarization data

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    We present a data analysis pipeline for CMB polarization experiments, running from multi-frequency maps to the power spectra. We focus mainly on component separation and, for the first time, we work out the covariance matrix accounting for errors associated to the separation itself. This allows us to propagate such errors and evaluate their contributions to the uncertainties on the final products.The pipeline is optimized for intermediate and small scales, but could be easily extended to lower multipoles. We exploit realistic simulations of the sky, tailored for the Planck mission. The component separation is achieved by exploiting the Correlated Component Analysis in the harmonic domain, that we demonstrate to be superior to the real-space application (Bonaldi et al. 2006). We present two techniques to estimate the uncertainties on the spectral parameters of the separated components. The component separation errors are then propagated by means of Monte Carlo simulations to obtain the corresponding contributions to uncertainties on the component maps and on the CMB power spectra. For the Planck polarization case they are found to be subdominant compared to noise.Comment: 17 pages, accepted in MNRA

    TEM Nanostructural Investigation of Ag-Conductive Filaments in Polycrystalline ZnO-Based Resistive Switching Devices

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    Memristive devices based on a resistive switching mechanism are considered very promising for nonvolatile memory and unconventional computing applications, even though many details of the switching mechanisms are not yet fully understood. Here, we report a nanostructural study by means of high-resolution transmission electron microscopy and spectroscopy techniques of a Ag/ZnO/Pt memristive device. To ease the localization of the filament position for its characterization, we propose to use the guiding effect of regular perturbation arrays obtained by FIB technology to assist the filament formation. HRTEM and EDX were used to identify the composition and crystalline structure of the so-obtained conductive filaments and surrounding regions. It was determined that the conducting paths are composed mainly of monocrystalline Ag, which remains polycrystalline in some circumstances, including the zone where the switching occurs and at secondary filaments created at the grain boundaries of the polycrystalline ZnO matrix. We also observed that the ZnO matrix shows a degraded quality in the switching zone, while it remains unaltered in the rest of the memristive device

    Sign-changing tower of bubbles for a sinh-Poisson equation with asymmetric exponents

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    Motivated by the statistical mechanics description of stationary 2D-turbulence, for a sinh-Poisson type equation with asymmetric nonlinearity, we construct a concentrating solution sequence in the form of a tower of singular Liouville bubbles, each of which has a different degeneracy exponent. The asymmetry parameter γ(0,1]\gamma\in(0,1] corresponds to the ratio between the intensity of the negatively rotating vortices and the intensity of the positively rotating vortices. Our solutions correspond to a superposition of highly concentrated vortex configurations of alternating orientation; they extend in a nontrivial way some known results for γ=1\gamma=1. Thus, by analyzing the case γ1\gamma\neq1 we emphasize specific properties of the physically relevant parameter γ\gamma in the vortex concentration phenomena

    Benefits and challenges of Bbg data in healthcare. An overview of the European initiatives

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    Healthcare systems around the world are facing incredible challenges due to the ageing population and the related disability, and the increasing use of technologies and citizen's expectations. Improving health outcomes while containing costs acts as a stumbling block. In this context, Big Data can help healthcare providers meet these goals in unprecedented ways. The potential of Big Data in healthcare relies on the ability to detect patterns and to turn high volumes of data into actionable knowledge for precision medicine and decision makers. In several contexts, the use of Big Data in healthcare is already offering solutions for the improvement of patient care and the generation of value in healthcare organizations. This approach requires, however, that all the relevant stakeholders collaborate and adapt the design and performance of their systems. They must build the technological infrastructure to house and converge the massive volume of healthcare data, and to invest in the human capital to guide citizens into this new frontier of human health and well-being. The present work reports an overview of best practice initiatives in Europe related to Big Data analytics in public health and oncology sectors, aimed to generate new knowledge, improve clinical care and streamline public health surveillance

    Approximate NNLO Threshold Resummation in Heavy Flavour Decays

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    We present an approximate NNLO evaluation of the QCD form factor resumming large logarithmic perturbative contributions in semi-inclusive heavy flavour decays.Comment: 16 pages, 3 figures, Latex; minor changes; 2 figures adde

    Nuclear expansion and symmetry energy of hot nuclei

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    The decrease in the symmetry energy of hot nuclei populated in 58^{58}Ni + 58^{58}Ni, 58^{58}Fe + 58^{58}Ni and 58^{58}Fe + 58^{58}Fe reactions at beam energies of 30, 40, and 47 MeV/nucleon, as a function of excitation energy is studied. It is observed that this decrease is mainly a consequence of increasing expansion or decreasing density rather than the increasing temperature. The results are in good agreement with the recently reported microscopic calculation based on the Thomas-Fermi approach. An empirical relation to study the symmetry energy of finite nuclei in various mass region is proposed.Comment: 10 pages, 2 figure

    Improving prosthetic selection and predicting BMD from biometric measurements in patients receiving total hip arthroplasty

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    There are two surgical approaches to performing total hip arthroplasty (THA): a cemented or uncemented type of prosthesis. The choice is usually based on the experience of the orthopaedic surgeon and on parameters such as the age and gender of the patient. Using machine learning (ML) techniques on quantitative biomechanical and bone quality data extracted from computed tomography, electromyography and gait analysis, the aim of this paper was, firstly, to help clinicians use patient-specific biomarkers from diagnostic exams in the prosthetic decision-making process. The second aim was to evaluate patient long-term outcomes by predicting the bone mineral density (BMD) of the proximal and distal parts of the femur using advanced image processing analysis techniques and ML. The ML analyses were performed on diagnostic patient data extracted from a national database of 51 THA patients using the Knime analytics platform. The classification analysis achieved 93% accuracy in choosing the type of prosthesis; the regression analysis on the BMD data showed a coefficient of determination of about 0.6. The start and stop of the electromyographic signals were identified as the best predictors. This study shows a patient-specific approach could be helpful in the decision-making process and provide clinicians with information regarding the follow up of patients

    Two-photon exclusive decays Bsη(η)γγB_s \to \eta (\eta') \gamma\gamma and BKγγB \to K \gamma\gamma

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    The exclusive decay modes BKγγB \to K \gamma\gamma and Bsη(η)γγB_s \to \eta (\eta') \gamma\gamma are shown to have significant branching ratios of approximately 0.5×1070.5\times 10^{-7}. This first calculation of these modes employs a model based on a cascade transition BVγPγγB\to V\gamma\to P\gamma\gamma for estimating the long-distance contribution and the process bsγγb\to s\gamma\gamma for the short distance one.Comment: 11 Page

    Long Distance Contribution to sdγs \to d\gamma and Implications for ΩΞγ,BsBdγ\Omega^-\to \Xi ^-\gamma, B_s \to B_d^*\gamma and bsγb \to s\gamma

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    We estimate the long distance (LD) contribution to the magnetic part of the sdγs \to d\gamma transition using the Vector Meson Dominance approximation (V=ρ,ω,ψi)(V=\rho,\omega,\psi_i). We find that this contribution may be significantly larger than the short distance (SD) contribution to sdγs \to d\gamma and could possibly saturate the present experimental upper bound on the ΩΞγ\Omega^-\to \Xi^-\gamma decay rate, ΓΩΞγMAX3.7×109\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} \simeq 3.7\times10^{-9}eV. For the decay BsBdγB_s \to B^*_d\gamma, which is driven by sdγs \to d\gamma as well, we obtain an upper bound on the branching ratio BR(BsBdγ)<3×108BR(B_s \to B_d^*\gamma)<3\times10^{-8} from ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma}. Barring the possibility that the Quantum Chromodynamics coefficient a2(ms)a_2(m_s) be much smaller than 1, ΓΩΞγMAX\Gamma^{\rm MAX}_{\Omega^-\to \Xi^-\gamma} also implies the approximate relation 23igψi2(0)mψi212gρ2(0)mρ2+16gω2(0)mω2\frac{2}{3} \sum_i \frac{g^2_{\psi_i}(0)}{m^2_{\psi_i}} \simeq \frac{1}{2} \frac{g^2_\rho(0)}{m^2_\rho} + \frac{1}{6}\frac{g^2_\omega(0)}{m^2_\omega}. This relation agrees quantitatively with a recent independent estimate of the l.h.s. by Deshpande et al., confirming that the LD contributions to bsγb \to s\gamma are small. We find that these amount to an increase of (4±2)%(4\pm2)\% in the magnitude of the bsγb \to s \gamma transition amplitude, relative to the SD contribution alone.Comment: 16 pages, LaTeX fil

    Peripersonal space representation develops independently from visual experience

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    Our daily-life actions are typically driven by vision. When acting upon an object, we need to represent its visual features (e.g. shape, orientation, etc.) and to map them into our own peripersonal space. But what happens with people who have never had any visual experience? How can they map object features into their own peripersonal space? Do they do it differently from sighted agents? To tackle these questions, we carried out a series of behavioral experiments in sighted and congenitally blind subjects. We took advantage of a spatial alignment effect paradigm, which typically refers to a decrease of reaction times when subjects perform an action (e.g., a reach-To-grasp pantomime) congruent with that afforded by a presented object. To systematically examine peripersonal space mapping, we presented visual or auditory affording objects both within and outside subjects' reach. The results showed that sighted and congenitally blind subjects did not differ in mapping objects into their own peripersonal space. Strikingly, this mapping occurred also when objects were presented outside subjects' reach, but within the peripersonal space of another agent. This suggests that (the lack of) visual experience does not significantly affect the development of both one's own and others' peripersonal space representation
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