4,649 research outputs found

    Cartesian Bicategories II

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    The notion of cartesian bicategory, introduced by Carboni and Walters for locally ordered bicategories, is extended to general bicategories. It is shown that a cartesian bicategory is a symmetric monoidal bicategory

    First results from an aging test of a prototype RPC for the LHCb Muon System

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    Recent results of an aging test performed at the CERN Gamma Irradiation Facility on a single--gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge of about 0.45 C/cm2^2, corresponding to about 4 years of LHCb running at the highest background rate. The performance of the chamber has been studied under several photon flux values exploiting a muon beam. A degradation of the rate capability above 1 kHz/cm2^2 is observed, which can be correlated to a sizeable increase of resistivity of the chamber plates. An increase of the chamber dark current is also observed. The chamber performance is found to fulfill the LHCb operation requirements.Comment: 6 pages, 9 figures, presented at the International Workshop on Aging Phenomena in Gaseous Detectors'', DESY-Hamburg (Germany), October 200

    Preliminary results of an aging test of RPC chambers for the LHCb Muon System

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    The preliminary results of an aging test performed at the CERN Gamma Irradiation Facility on a single--gap RPC prototype developed for the LHCb Muon System are presented. The results are based on an accumulated charge density of 0.42 C/cm^2, corresponding to about 4 years of LHCb running at the highest background rate. We observe a rise in the dark current and noise measured with source off. The current drawn with source on steadily decreased, possibly indicating an increase of resistivity of the chamber plates. The performance of the chamber, studied with a muon beam under several photon flux values, is found to still fulfill the LHCb operation requirements.Comment: 4 pages, 6 figures, presented at RPC2001, VIth Workshop on Resistive Plate Chambers and Related Detectors, November 26-27 2001, Coimbra, Portuga

    Humans and viticulture in Sardinia: the history and social relations as signs of identity of the wine-growing area.

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    The premise of this paper is that viticulture is an expression of history and social relations. In this sense, we embrace a post-modern vision of development that characterized both economic and cultural geography and agricultural economics. Such an approach does consider culture as an element of mediation between humans and the nature, placing it at the heart of the wine-growing territory. So history and social relations have influenced the today spatial densification by types of grape and the persistence, the reduction and/or disappearance of vines\u2019 cultivations due to the different level of integration between humans and wine territories in the Italian region of Sardinia. In this region, there are selected areas where winegrowers have been forced to grub vineyards up, depleting the regional viticultural heritage, others\u2013\u2013within which the fabric of the system of social relationships were denser\u2013\u2013and where we saw a real rush to purchase of replanting rights for the expansion of the production surface for the increasing of production. The aim of this paper is to highlight the role of history and social relations in the determination of the structure of the regional viticulture through the identification and analysis of diverse case studies

    Supersonic investigation of two dimensional hypersonic exhaust nozzles

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    An experimental investigation was conducted in the NASA Lewis 10 x 10 ft supersonic Wind Tunnel to determine the performance characteristics of 2D hypersonic exhaust nozzles/afterbodies at low supersonic conditions. Generally, this type of application requires a single expansion ramp nozzle (SERN) that is highly integrated with the airframe of the hypersonic vehicle. At design conditions (hypersonic speeds), the nozzle generally exhibits acceptable performance. At off-design conditions (transonic to mid-supersonic speeds), nozzle performance of a fixed geometry configuration is generally poor. Various 2-D nozzle configurations were tested at off-design conditions from Mach 2.0 to 3.5. Performance data is presented at nozzle pressure ratios from 1 to 35. Jet exhaust was simulated with high-pressure air. To study performance of different geometries, nozzle configurations were varied by interchanging the following model parts: internal upstream contour, expansion ramp, sidewalls, and cowl

    Today is already Yesterday:\ua0The\ua0Glossa XX1 architectural project for the Italian Memorial in Block 21 at Auschwitz

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    The architect of the proposed Glossa XX Architectural Project for the Italian Memorial in Block " at Auschwitz, presents and elucidates the restorations it involves and its response to criticisms made by the Direction of the Auschwitz Museum

    Inferior alveolar nerve impairment after mandibular sagittal split osteotomy: an analysis of spontaneous recovery pattern observed in 60 patients

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    Sensory impairment after bilateral sagittal split osteotomy (BSSO) due to inferior alveolar nerve (IAN) lesions may be either temporary or permanent and either complete or partial. The aim of this prospective study is to evaluate, by means of objective sensory testing, IAN sensory disturbances development in patients who underwent BSSO.IAN sensory disturbances development at the first week, fourth week, sixth month, and twelfth month of follow-up review in a group of 60 patients who underwent BSSO from January 1, 1998, to July 31, 1999, at the Maxillofacial Surgery Department of the "La Sapienza" University of Rome. The 60 patients were examined in the presurgical period; the IAN functionality regarding thermal sensibility, nociception, and two-point discrimination, was assessed at follow-up in 120 sides. In our study the highest rate of spontaneous recovery of the entire IAN functionality was observed at the sixth month. This finding witnesses how neuropraxia and axonotmesis give a spontaneous recovery that most frequently occurs within 6 months from surgery, independently from age and sex of the patient. The persistence of anesthesia over 12 months could be a sign of neurotmesis

    Monte Carlo Study of the Arrival Time Distribution of Particles in Extensive Air Showers in the Energy Range 1-100 TeV

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    A detailed simulation of vertical showers in atmosphere produced by primary gammas and protons, in the energy range 1-100 TeV, has been performed by means of the FLUKA Monte Carlo code, with the aim of studying the time structure of the shower front at different detector heights. It turns out that the time delay distribution can be fitted using few parameters coincident with the distribution central moments. Such parameters exhibit a smooth behaviour as a function of energy. These results can be used both for detector design and for the interpretation of the existing measurements. Differences in the time structure between gamma and proton induced showers are found and explained in terms of the non-relativistic component of extensive air showers

    Diagnosis of bell palsy with gadolinium magnetic resonance imaging

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    Bell palsy is a condition resulting from a peripheral edematous compression on the nervous fibers of the facial nerve. This pathological condition often has clinical characteristics of no importance and spontaneously disappears in a short time in a high percentage of cases. Facial palsy concerning cranial nerve VII can also be caused by other conditions such as mastoid fracture, acoustic neurinoma, tumor spread to the temporal lobe (e.g., cholesteatoma), neoformation of the parotid gland, Melkersson-Rosenthal syndrome, and Ramsay-Hunt syndrome. Therefore, it is important to adopt an accurate diagnostic technique allowing the rapid detection of Bell palsy and the exclusion of causes of facial paralysis requiring surgical treatment. Magnetic resonance imaging (MRI) with medium contrast of the skull shows a marked increase in revealing lesions, even of small dimensions, inside the temporal bone and at the cerebellopontine angle. The authors present a clinical case to show the important role played by gadolinium MRI in reaching a diagnosis of Bell palsy in the differential diagnosis of the various conditions that determine paralysis of the facial nerve and in selecting the most suitable treatment or surgery to be adopted
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