389 research outputs found

    L^p and Schauder estimates for nonvariational operators structured on H\"ormander vector fields with drift

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    We consider linear second order nonvariational partial differential operators of the kind a_{ij}X_{i}X_{j}+X_{0}, on a bounded domain of R^{n}, where the X_{i}'s (i=0,1,2,...,q, n>q+1) are real smooth vector fields satisfying H\"ormander's condition and a_{ij} (i,j=1,2,...,q) are real valued, bounded measurable functions, such that the matrix {a_{ij}} is symmetric and uniformly positive. We prove that if the coefficients a_{ij} are H\"older continuous with respect to the distance induced by the vector fields, then local Schauder estimates on X_{i}X_{j}u, X_{0}u hold; if the coefficients belong to the space VMO with respect to the distance induced by the vector fields, then local L^{p} estimates on X_{i}_{j}u, X_{0}u hold. The main novelty of the result is the presence of the drift term X_{0}, so that our class of operators covers, for instance, Kolmogorov-Fokker-Planck operators

    Liouvillian gap and out-of-equilibrium dynamics of a sunburst Kitaev ring: from local to uniform dissipation

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    We consider an open quantum system composed of a (1+1)(1+1)-dimensional Kitaev ring coupled with the environment via nn particle-loss dissipators in a \textit{sunburst} geometry. We describe the out-of-equilibrium dynamics of the whole apparatus in terms of Lindblad master equations and focus on the scaling behavior of the Liovillian gap Δλ\Delta_\lambda with the system size LL. We unveil different regimes, which depend primarily on the number of dissipation sources considered in the large-size limit and the dissipation strength ww, which may be either fixed or attenuated to zero as w∼1/Lw\sim1/L. In the second part, we develop a dynamic Finite-Size Scaling framework close to Continuous Quantum Transitions to monitor the time evolution of the critical correlations and the entanglement entropy, emphasizing the role of Δλ\Delta_\lambda in this regime.Comment: 14 pages, 14 figure

    Interferon free antiviral treatment of chronic hepatitis C in patients affected by β-thalassemia major

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    Chronic hepatitis C (CHC) significantly affects the prognosis of liver disease [1] and health related quality of life (HRQOL) in patients with β-thalassemia major [2, 3]. CHC cure is a crucial event in the prognosis of the disease, since prevents fibrosis progression, decreases the risk of hepatocellular carcinoma (HCC), and improves survival. Standard antiviral therapy with Pegylated Interferon (PEG-IFN) and Ribavirin (RBV) has long been the standard of care, despite its limited efficacy and increased ribavirin induced hematological adverse events in thalassemic patients [4]. Recently, several novel highly effective direct antiviral agents (DAAs) have been approved for HCV treatment, with impressive cure rates, higher than 90%, after 8–12 weeks of therapy and mild adverse events [5], but there are no published reports documenting the efficacy, safety and impact on QOL of available interferon-free antiviral regimens in patients with βthalassemia majo

    Antagonism of the prokineticin system prevents and reverses allodynia and inflammation in a mouse model of diabetes

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    Neuropathic pain is a severe diabetes complication and its treatment is not satisfactory. It is associated with neuroinflammation-related events that participate in pain generation and chronicization. Prokineticins are a new family of chemokines that has emerged as critical players in immune system, inflammation and pain. We investigated the role of prokineticins and their receptors as modulators of neuropathic pain and inflammatory responses in experimental diabetes. In streptozotocin-induced-diabetes in mice, the time course expression of prokineticin and its receptors was evaluated in spinal cord and sciatic nerves, and correlated with mechanical allodynia. Spinal cord and sciatic nerve pro- and anti-inflammatory cytokines were measured as protein and mRNA, and spinal cord GluR subunits expression studied. The effect of preventive and therapeutic treatment with the prokineticin receptor antagonist PC1 on behavioural and biochemical parameters was evaluated. Peripheral immune activation was assessed measuring macrophage and T-helper cytokine production. An up-regulation of the Prokineticin system was present in spinal cord and nerves of diabetic mice, and correlated with allodynia. Therapeutic PC1 reversed allodynia while preventive treatment blocked its development. PC1 normalized prokineticin levels and prevented the up-regulation of GluN2B subunits in the spinal cord. The antagonist restored the pro-/anti-inflammatory cytokine balance altered in spinal cord and nerves and also reduced peripheral immune system activation in diabetic mice, decreasing macrophage proinflammatory cytokines and the T-helper 1 phenotype. The prokineticin system contributes to altered sensitivity in diabetic neuropathy and its inhibition blocked both allodynia and inflammatory events underlying disease

    Multiphysics Modeling of a Wearable Sensor for Sweat Rate Measurements

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    6D physical interaction with a fully actuated aerial robot

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    This paper presents the design, control, and experimental validation of a novel fully-actuated aerial robot for physically interactive tasks, named Tilt-Hex. We show how the Tilt-Hex, a tilted-propeller hexarotor is able to control the full pose (position and orientation independently) using a geometric control, and to exert a full-wrench (force and torque independently) with a rigidly attached end-effector using an admittance control paradigm. An outer loop control governs the desired admittance behavior and an inner loop based on geometric control ensures pose tracking. The interaction forces are estimated by a momentum based observer. Control and observation are made possible by a precise control and measurement of the speed of each propeller. An extensive experimental campaign shows that the Tilt-Hex is able to outperform the classical underactuated multi-rotors in terms of stability, accuracy and dexterity and represent one of the best choice at date for tasks requiring aerial physical interaction

    Stochastic approach to hydraulic barrier design: an example in northeastern Italy

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    Volatile organic compounds, groundwater contamination, multi-layered aquifer syste

    The INSEAN E779a Propeller Test Case: a Database For CFD Validation

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    In the last few years, remarkable improvements in numerical modeling of viscous flows around marine propellers have been obtained. In particular, Reynolds Averaged Navier-Stokes (RANS) equation solvers start to be widely used to analyze viscosity effects on propulsors at model-scale Reynolds number, in the case of uniform inflow and non-cavitating conditions. The development of such advanced computational tools is required, especially in modern propeller design, where for reducing propeller-induced hull vibrations, efficiency decay and noise generation due to cavitation, there is a continuous trend towards an increased complexity of the blade geometry, primarily due to the low aspect ratio and to the skew of marine propellers, which cause strong three-dimensional effects. This complexity requires a better knowledge of the wake characteristics in terms of the mean field and turbulent quantities. Therefore, there is a rising interest on detailed data of the velocity flow field around the blades and in the wake, supporting the flow modeling and the validation of the computational tools. Starting since 1997 at INSEAN started a project aimed to obtain high quality data for CFD validation. Measurements of velocity fields, radiated pressure fields cavitation patterns were performed. The chosen propeller was the INSEAN E779a, propeller which was already investigated in the 80\u27s by adopting phase sampling LDV technique

    Indexed maximal left atrial volume predicts response to cardiac resynchronization therapy

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    Aims Cardiac resynchronization therapy (CRT) has shown morbidity and mortality benefits in patients with advanced congestive heart failure (HF). Since about one-third of the patients did not appear to respond to CRT, it would seem reasonable to try to identify patients more accurately before implantation. Left atrial (LA) dimension has been proposed as a powerful outcome predictor in patients with heart disease. Accordingly, the aim of this study is to prospectively assess the predictive value of LA for selecting CRT responders. Methods Fifty two consecutive patients with refractory HF, sinus rhythm and left bundle branch block were enrolled in the study and planned for CRT implantation. Clinical and echocardiographic evaluations were performed before CRT implantation and after 6 months. Three LA volumes indexed to body surface area (iLAV) were computed to evaluate the LA complexity: maximal LAV (iLAVmax), LAV just before atrial systole (iLAVpre), and minimal LAV (iLAVpost). CRT responders were defined as those who presented a reduction of > 10% in LVESVi at 6-month follow-up. Results Responders (63%) and nonresponders (37%) had similar baseline clinical characteristics and pre-implantation LV volumes. However, baseline LA volumes were significantly associated with the extent of LV reverse remodeling: in particular, baseline iLAVmax was remarkably lower in responders than in nonresponders (50.2 ± 14.1 ml/m2 vs 65.8 ± 15.7 ml/m2, p = 0.001) resulting predictive for CRT response. Conclusion Patients with small iLAV result as better responders to CRT than larger one. iLAVmax is an independent predictor of LV reverse remodeling and allows to indentify the best candidates for CRT. © 2013 Elsevier Ireland Ltd
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