1,504 research outputs found

    An Integro-Differential Conservation Law arising in a Model of Granular Flow

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    We study a scalar integro-differential conservation law. The equation was first derived in [2] as the slow erosion limit of granular flow. Considering a set of more general erosion functions, we study the initial boundary value problem for which one can not adapt the standard theory of conservation laws. We construct approximate solutions with a fractional step method, by recomputing the integral term at each time step. A-priori L^\infty bounds and BV estimates yield convergence and global existence of BV solutions. Furthermore, we present a well-posedness analysis, showing that the solutions are stable in L^1 with respect to the initial data

    Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.

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    Idiopathic thrombocytopenic purpura (ITP) is characterized by a low platelet count, which is the result of both increased pla- telet destruction and insufficient platelet production. Although the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modu- lation have been identified. Conventional treatments for ITP aim at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents,AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances in both fields

    The boundary Riemann solver coming from the real vanishing viscosity approximation

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    We study a family of initial boundary value problems associated to mixed hyperbolic-parabolic systems: v^{\epsilon} _t + A (v^{\epsilon}, \epsilon v^{\epsilon}_x ) v^{\epsilon}_x = \epsilon B (v^{\epsilon} ) v^{\epsilon}_{xx} The conservative case is, in particular, included in the previous formulation. We suppose that the solutions vϔv^{\epsilon} to these problems converge to a unique limit. Also, it is assumed smallness of the total variation and other technical hypotheses and it is provided a complete characterization of the limit. The most interesting points are the following two. First, the boundary characteristic case is considered, i.e. one eigenvalue of AA can be 00. Second, we take into account the possibility that BB is not invertible. To deal with this case, we take as hypotheses conditions that were introduced by Kawashima and Shizuta relying on physically meaningful examples. We also introduce a new condition of block linear degeneracy. We prove that, if it is not satisfied, then pathological behaviours may occur.Comment: 84 pages, 6 figures. Text changes in Sections 1 and 3.2.3. Added Section 3.1.2. Minor changes in other section

    Trade Statistics of the Zollverein, 1834-1871

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    The purpose of this paper is to highlight the fact that the lack of useable German trade statistics for the period preceding the German political unifica- tion is not a fatality. The documents published during the Zollverein period by the Central Bureau of the Zollverein, the Statistische Uebersichten über Waaren- Verkehr und Zoll-Ertrag im Deutschen Zoll-Vereine für das Jahr..., do not provide prices nor trade flows in value nor any indication of countries of ultimate origin and destination. To overcome these imperfections, a great number of estimates of Zollverein trade statistics have been published since 1842 but they are ques- tionable as well. Nevertheless, the good quality of Statistische Übersichten’s quantity data should make possible the reconstruction of consistent series of German trade, total, by product and in value, over the period 1834-1871

    New Insight on Medieval Painting in Sicily: The Virgin Hodegetria Panel in Monreale Cathedral (Palermo, Italy)

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    : The Virgin Hodegetria, located in the Cathedral of Santa Maria Nuova in Monreale, near Palermo (Italy), probably dating the first half of the 13th century, is one of the earliest examples of medieval panel painting in Sicily. A diagnostic campaign was carried out on the panel aiming to identify the constituting materials and the executive technique, as well as to assess the state of conservation for supporting the methodological choice of the restoration intervention. Both non invasive (X-ray radiography, digital microscope, multispectral imaging, ED-X-ray fluorescence) and micro-invasive (polarised light microscopy, ESEM-EDX, ATR-FTIR spectroscopy and micro-Raman spectroscopy) analyses were performed. According to the results, the executive technique followed the 13th–14th-century Italian painting tradition. A complex structure was applied on the wooden support, consisting of a double layer of canvas and several ground layers of gypsum and glue based binder. The underdrawing was made by a brush using carbonaceous black pigment. The original palette includes red ochre, red lead, azurite, carbon black and bone black. During the several restorations, mercury-based red, indigo, smalt blue, orpiment and synthetic mars were used. The original silver leaf of the frame was covered with red tin-based lake and subsequently regilded with gold leaf. Proteinaceous and oil binders were also detecte

    Cross-species infectivity of H3N8 influenza virus in an experimental infection in swine

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    Avian influenza A viruses have gained increasing attention due to their ability to cross the species barrier and cause severe disease in humans and other mammal species as pigs. H3 and particularly H3N8 viruses, are highly adaptive since they are found in multiple avian and mammal hosts. H3N8 viruses have not been isolated yet from humans; however, a recent report showed that equine influenza A viruses (IAVs) can be isolated from pigs, although an established infection has not been observed thus far in this host. To gain insight into the possibility of H3N8 avian IAVs to cross the species barrier into pigs, in vitro experiments and an experimental infection in pigs with four H3N8 viruses from different origins (equine, canine, avian, and seal) were performed. As a positive control, an H3N2 swine influenza virus A was used. Although equine and canine viruses hardly replicated in the respiratory systems of pigs, avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs without previous adaptation. Interestingly, antibodies against hemagglutinin could not be detected after infection by hemagglutination inhibition (HAI) test with avian and seal viruses. This phenomenon was observed not only in pigs but also in mice immunized with the same virus strains. Our data indicated that H3N8 IAVs from wild aquatic birds have the potential to cross the species barrier and establish successful infections in pigs that might spread unnoticed using the HAI test as diagnostic tool.We thank Jaime Maldonado and HIPRA (Spain) for the A/Swine/Spain/ 54008/2004 (H3N2) strain, Edward J. Dubovi and Cornell University for the A/Canine/NY/105447/08 (H3N8) IAV strain, T. M. Chambers and the University of Kentucky for the A/Equine/OH/1/03 (H3N8) IAV strain, and Hon Ip and the U.S. Geological Survey National Wildlife Health Center for the A/American black duck/Maine/44411-532/2008 (H3N8) and the A/Harbor Seal/New Hampshire/179629/2011 (H3N8) IAV strains. We thank Sergio López, David Solanes, Francisco X. Abad, Jordi Alberola, Jaume Martorell, and Eduard J. Cunilleras for help in providing different samples and during the experimental infections, as well as the personnel in Cat3 laboratories and the animal house. We thank Adolfo García-Sastre for providing materials and for support as the principal investigator of the NIAID-funded Center for Research in Influenza Pathogenesis (HHSN266200700010C). The research leading to these results received funding from the European Community’s Seventh Framework Programme (FP7, 2007-2013), the Research Infrastructures Action under grant FP7-228393 (a NADIR project), and projects AGL2010-22200-C02-01 and AGL2007-60274 of the Spanish Ministry of Science and Innovation

    A Semi-Lagrangian scheme for a modified version of the Hughes model for pedestrian flow

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    In this paper we present a Semi-Lagrangian scheme for a regularized version of the Hughes model for pedestrian flow. Hughes originally proposed a coupled nonlinear PDE system describing the evolution of a large pedestrian group trying to exit a domain as fast as possible. The original model corresponds to a system of a conservation law for the pedestrian density and an Eikonal equation to determine the weighted distance to the exit. We consider this model in presence of small diffusion and discuss the numerical analysis of the proposed Semi-Lagrangian scheme. Furthermore we illustrate the effect of small diffusion on the exit time with various numerical experiments

    La traduction dans une perspective de genre. Enjeux politiques, Ă©ditoriaux et professionnels

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    Cet ouvrage s’inscrit dans le cadre thĂ©orique de la traduction conçue dans une perspective de genre, un contexte qui sous-tend que la langue n’est jamais neutre, et que tout acte de langage a une dimension politique et des retombĂ©es du point de vue culturel et social. Les essais qu’il propose abordent quelques sujets majeurs dans ce domaine. Le livre s’ouvre avec une rĂ©flexion de nature gĂ©nĂ©rale sur la circulation difficile au niveau transnational de la terminologie et de certains concepts des Ă©tudes de genre ainsi que sur les problĂšmes posĂ©s par leur traduction. Dans le cadre d’une rĂ©flexion attentive Ă  la dimension professionnelle, l’expĂ©rience de Barbara Bray, mĂ©diatrice interculturelle pour la BBC, est ensuite prĂ©sentĂ©e comme un acte politique d’engagement d’une traductrice d’exception. La question du “gender bias” dans la traduction automatique, un enjeu qu’il est dĂ©sormais indispensable d’affronter, fait l’objet d’une analyse visant Ă  en cerner les causes et Ă  suggĂ©rer des solutions possibles. Ces essais sont suivis d’études qui se penchent sur l’édition de textes littĂ©raires traduits et s’intĂ©ressent en particulier aux enjeux de la traduction du langage non binaire, ainsi qu’aux politiques Ă©ditoriales de diverses maisons d’édition de littĂ©rature jeunesse. Ces deux domaines, qui n’ont Ă©tĂ© abordĂ©s par les Ă©tudes de genre que trĂšs rĂ©cemment, ouvrent des perspectives de recherche nouvelles et fĂ©condes
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