1,269 research outputs found

    OROGRAPHIC INFLUENCE ON DEEP CONVECTION: CASE STUDY AND SENSITIVITY EXPERIMENTS

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    The non hydrostatic convection resolving model MOLOCH is employed in order to evaluate its capability to realistically simulate the evolution of a mesoscale convective system responsible for an episode of heavy rainfall and flood over southeastern France (Gard event). Numerical experiments indicate large sensitivity of precipitation amounts and distribution, due to different cell organization and propagation, to the specification of the initial conditions. Further experiments, aimed at studying the role played by the orography in triggering the convection and controlling its evolution, have been performed in order to characterize sensitivity to ambient wind and orography. Although the convective system remained almost stationary for many hours with maximum precipitation located at some distance upstream of the mountain main slope, simulations demonstrate that the presence of the orographic barrier is essential for both triggering and maintaining the mesoscale convective system. The intensity of precipitation turns out to be sensitive to small variations of the mean meridional wind component

    The Italian Consensus Conference on Pain in Neurorehabilitation

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    Pain is frequent in several neurological conditions, such as stroke, Parkinson’s disease, multiple sclerosis, diabetic neuropathy, but it is often underestimated and therefore untreated or not successfully treated. Pain reduces quality of life, it may be the cause of adaptive disorders (such as anxiety and depression) and, in patients undergoing rehabilitation, it may negatively impact rehabilitation procedures and hamper the outcome. Unfortunately, there are no significant data regarding the impact of pain in neurorehabilitation patients and what would be the impact of an appropriate pain treatment on rehabilitation outcome. Accordingly, there are no guidelines providing indications on how to treat pain in patients with pain during rehabilitation treatment and thereafter. Given this background, and to comply with the Italian law 38 released on 2010 by the Italian Ministry of Health to guarantee adequate care and treatment of patients with pain both in hospital and in primary care, the Italian Society for Neurological Rehabilitation (SIRN) along with the Italian Society for Physical and Rehabilitative Medicine (SIMFER), promoted a work-in-progress platform, the Italian Consensus Conference on Pain in Neurorehabilitation (ICCPNR)

    Orographic triggering of long lived convection in three dimensions

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    A significant fraction of the occurrences of intense flash floods is due to quasi-stationary or long-lived convection that may insist on the same place for many hours, producing high values of accumulated precipitation. One of the elements that favour the initiation and anchoring of the convective system (MCS) is the orography. In one of the most severe floods (Gard basin in southern France, 8-9 September 2002), the orography of the Massif Central played a rather unusual role, favouring the onset and maintenance of the MCS at some distance upstream of the main orographic slope. In the present work the initial atmospheric conditions of this event have been largely idealized, taking horizontally uniform values for wind, temperature and humidity profiles, and a simplified isolated orography representing the sole Massif Central. A convective system is initiated in the non-hydrostatic simulations, embedded in a quasi-stationary solution of flow over the orography. It is shown that the triggering of convection occurs in the convergence zone immediately upstream of the orographic obstacle, at an altitude comparable with the mountain height. The subsequent growth of the mesoscale convective system is associated with a slow eastward drift, with the intense precipitation located upstream of the mountain and with the formation of a gust front that propagates against the incoming basic flow. Sensitivity experiments show that the development of convection critically depends on mountain height and moisture content. Although the results obtained in such idealized conditions do not reflect all the observed characteristics of the real event, they contribute to clarify the role of the orography in triggering and maintaining strong convection

    Distributed energy-aware resource allocation in multi-antenna multi-carrier interference networks with statistical CSI

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    Resource allocation for energy efficiency optimization in multi-carrier interference networks with multiple receive antennas is tackled. First, a one-hop network is considered, and then, the results are extended to the case of a two-hop network in which amplify-and-forward relaying is employed to enable communication. A distributed algorithm which optimizes a system-wide energy-efficient performance function, and which is guaranteed to converge to a stable equilibrium point, is provided. Unlike most previous works, in the definition of the energy efficiency, not only the users' transmit power but also the circuit power that is required to operate the devices is taken into account. All of the proposed procedures are guaranteed to converge and only require statistical channel state information, thus lending themselves to a distributed implementation. The asymptotic regime of a saturated network in which both the active users and the number of receive antennas deployed in each receiver grow large is also analyzed. Numerical results are provided to confirm the merits of the proposed algorithms

    Evaluation of an Internet Document Delivery Service

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    An Internet-based Document Delivery Service (DDS) has been developed within the framework of the CNR ( the Italian Research National Council) Project BiblioMIME, in order to take advantage of new Internet technologies and promote cooperation among CNR and Italian university libraries. Adopting such technologies changes the traditional organisation of DDS and may drastically reduce costs and delivery times. An information system managing DDS requests and monitoring the temporal evolution of the service has been implemented, running on the local-area network of a test-site library. It aims to track number and types of documents requested and received, user distribution, delivery times and types (surface mail, fax, Internet), to automate repetitive manual procedures and to deal with the various accounting methods used by other libraries. Transmission of documents is carried out by means of an e-mail/Web gateway system supporting document exchange via Internet, which assists receiving libraries in retrieving requested documents. This paper describes the architecture and main design features of the e-mail/Web gateway server (the BiblioMime server). This approach permits librarians to continue using e-mail service to send large documents, while resolving problems that users may encounter when downloading large size files with e-mail agents. The library operator sends the document as an attachment to the destination address; on fly the e-mail server extracts and saves the attachments in a web-server disk file and substitutes them with a new message part that includes an URL pointing to the saved document. The receiver can download these large objects by means of a user-friendly browser. We further discuss the data gathered during the triennium 1998-2000; this consists of about 5,000 DDS transactions per annum with 300 other Italian scientific and bio-medical libraries and commercial document suppliers. Use of the instruments described above allowed us to evaluate the performance of service "before" and "after" the use of Internet Document Delivery and to extract some critical data regarding DDS. Those include: a) libraries with which we have greater numbers of exchanges and their turnaround times; b) extraordinary reduction in costs and delivery times; c) the most frequently requested serial titles (allowing cost-effective decisions on new subscriptions); d) impact on DDS of library participation in consortia which allow user access to greater numbers of online serials

    Equilibrium states for potentials with \sup\phi - \inf\phi < \htop(f)

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    In the context of smooth interval maps, we study an inducing scheme approach to prove existence and uniqueness of equilibrium states for potentials Ď•\phi with he `bounded range' condition \sup \phi - \inf \phi < \htop, first used by Hofbauer and Keller. We compare our results to Hofbauer and Keller's use of Perron-Frobenius operators. We demonstrate that this `bounded range' condition on the potential is important even if the potential is H\"older continuous. We also prove analyticity of the pressure in this context.Comment: Added Lemma 6 to deal with the disparity between leading eigenvalues and operator norms. Added extra references and corrected some typo

    Fold-Saddle Bifurcation in Non-Smooth Vector Fields on the Plane

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    This paper presents results concerning bifurcations of 2D piecewise-smooth dynamical systems governed by vector fields. Generic three parameter families of a class of Non-Smooth Vector Fields are studied and its bifurcation diagrams are exhibited. Our main result describes the unfolding of the so called Fold-Saddle singularity
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