2,769 research outputs found

    Photoproduction of K∗+ΛK^{*+}\Lambda and K+Σ(1385)K^+\Sigma(1385) in the reaction \gamma \lowercase{p} \to K^+ \Lambda \pi^0 at Jefferson Lab

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    The search for missing nucleon resonances using coupled channel analysis has mostly been concentrated on NπN\pi and KYKY channels, while the contributions of K∗YK^*Y and KY∗KY^* channels have not been investigated thoroughly mostly due to the lack of data. With an integrated luminosity of about 75 pb−1pb^{-1}, the photoproduction data using a proton target recently collected by the CLAS Collaboration at Jefferson Lab with a photon energy range of 1.5-3.8 GeV provided large statistics for the study of light hyperon photoproduction through exclusive reactions. The reaction γp→K+Λπ0\gamma p \to K^+ \Lambda \pi^0 has been investigated. Preliminary results of the K∗+ΛK^{*+}\Lambda and K+Σ(1385)K^+\Sigma(1385) cross sections are not negligible compared with the KYKY channels. The Λπ0\Lambda \pi^0 invariant mass spectrum is dominated by the Σ(1385)\Sigma(1385) signal and no significant structure was found around the Σ(1480)\Sigma(1480) region.Comment: 4 pages, 3 figures, to be publised on the NSTAR05 proceeding

    Gouvernance régionale des politiques publiques « société de l'information » Rôle des acteurs publics régionaux et formes de gouvernance dans la diffusion des infrastructures et des usages : vers une analyse comparée de trois régions françaises

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    Over recent years, local authorities have shown an increasing interest in CITs, and as a result, appropriate public policies have been put in place. Through their application, these technologies are designed to run alongside planning and development policies. They are also regarded as a means of revitalizing participation in local democracy. The discourse underlying these political measures gives local politicians an opportunity to pay tribute to the ideology of the «information society», an icon for progress and modernity. While these public policies remain more or less similar in terms of aims and applications, in relation to strategies for planning, design, monitoring, and completion timetables, they nevertheless show a broad diversity. By building up an analytic template based on the example of three regions (Alsace, Provence Alpes Côte d'Azur and Bourgogne), this article aims to examine the way in which players at regional level make decisions, plan, put in place and monitor these «information society» policies.Depuis quelques années, les TIC font l'objet d'un intérêt croissant de la part des collectivités territoriales conduisant à la mise en place de politiques publiques dans ce domaine. A travers leurs applications, ces technologies sont conçues comme concourant à l'aménagement et au développement des territoires. Elles apparaissent également comme des vecteurs renouvelés de la participation des citoyens à la démocratie locale. Enfin, le discours qui sous-tend ces actions publiques peut donner l'occasion aux élus locaux de payer un tribu à l'idéologie de la « société de l'information », symbole de progrès et de modernité. Si les objectifs et les enjeux de ces politiques publiques restent relativement communs, celles ci se caractérisent néanmoins par une grande diversité (élaboration et conception, état d'avancement, modalités de mise en œuvre, etc.). A travers la construction d'une grille d'analyse sur l'exemple de trois régions : Alsace, Provence Alpes Côte d'Azur et Bourgogne, cette contribution se propose d'étudier la manière dont les acteurs publics régionaux décident, conçoivent, mettent en œuvre et contrôle ces politiques « société de l'information »

    Comment se développe les nouveaux médias de l'Internet. Une étude de cas : Cityvox.

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    Cityvox , société éditrice de sites Internet pour le grand-public, de services et de contenus en ligne, résume le phénomène d'apparition des nouveaux médias de l'Internet en France : start-up créée dans l'effervescence du gonflement de la bulle en 1999, elle survit à la crise du secteur, réussit à adapter son modèle d'affaires au nouveau contexte et est reprise en 2008 par Orange, principal acteur national du secteur des technologies de l'information et de la communication. Décrire l'histoire de cette entreprise permet de comprendre comment et pourquoi des modèles d'affaires robustes, rentables et pérennes s'inventent depuis quelques années dans ce secteur, marqué par l'explosion des usages et l'effervescence technologique. Cela permet ensuite d'analyser, sur un exemple de taille modeste mais significatif économiquement, les processus qui attaquent et déséquilibrent le secteur traditionnel des médias, le poussant à une mutation souvent vécue comme une crise

    Economie de la "société de l'information". Qoui de neuf ?

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    International audienceThe ideology of the "information society" is based on an economic story. This story discovers a "new economy" characterized by "dematerialization" whose the two consequences would be the "piracy" of works and the development of “Web 2.0 media" based on the direct management of information by the public. These four "discoveries" of the economic ideology of the information society are refuted not only on the theoretical level but also by a case study of an Internet-based firm (Cityvox). The real changes that affect the economy of informational goods in relation to the development of digital technologies can be described as a contemporary manifestation of capitalist and industrial economy principles, regarding the development and transfer of value and competition between firms.L'idéologie de la « société de l'information » repose notamment sur un récit économique. Ce récit met l'accent sur une « nouvelle économie », caractérisée par la « dématérialisation », dont deux conséquences seraient le « piratage » des oeuvres et le développement de « médias Web 2.0 » fondés sur la gestion directe de l'information par le public. Dans ce texte, nous allons réfuter quatre « découvertes » de l'idéologie économique de la société de l'information à la fois sur le plan théorique et par l'étude d'un cas d'entreprise de l'Internet, la société Cityvox. Les changements réels qui affectent l'économie des biens informationnels en relation avec le développement des technologies numériques doivent plutôt être décrits comme la manifestation contemporaine de fondamentaux de l'économie capitaliste, industrielle et marchande concernant la formation et la circulation de la valeur et la concurrence entre les firmes

    IDENTIFYING THE IMMUNE RELATED METABOLIC PROPERTIES OF PANCREATIC CANCER USING NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY AND DYNAMIC MAGNETIC RESONANCE SPECTROSCOPIC IMAGING WITH HYPERPOLARIZED PYRUVATE

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    Despite its relatively low incidence, pancreatic cancer was the fourth leading cause of cancer-related death in the US in 2015. This is due in part to pancreatic cancer’s natural resistance to both chemotherapy and radiotherapy. Immunotherapy presents an attractive potential treatment approach, but initial trials in mice have proved ineffective. Because cancer cells exhibit a significant increase in metabolic activity relative to normal tissue, an understanding of the metabolic function of tumors in systems with different levels of immunocompetence is a critical first step to develop an understanding of the immune-related metabolic properties of the tumor, which have potential application in assessing a tumor’s response to immunotherapy. Magnetic resonance (MR) is an intrinsically low sensitivity technique, but dynamic nuclear polarization allows one to increase the MR signal by five orders of magnitude. As described by the Warburg effect, even in the presence of an ample amount of oxygen, tumors preferentially metabolize their energy via the inefficient process of glycolysis in which pyruvate is ultimately converted into lactate. Thus, by hyperpolarizing 13C-labelled pyruvate, one can spectroscopically observe the conversion of pyruvate to lactate in real time and quantify a tumor’s glycolytic conversion flux in vivo. In addition, the application of high-resolution 1H nuclear magnetic resonance metabolomics allows one globally analyze the entire water-soluble metabolome and quantify the relative concentrations of each metabolite in an extracted tumor tissue sample. By applying MR spectroscopic imaging with hyperpolarized pyruvate and NMR metabolomics, this study identifies clear metabolic biomarkers that can facilitate the assessment of metabolic changes between pancreatic tumors in mice cultivated in both immunocompromised and immunocompetent environments

    Autocalibration Region Extending Through Time: A Novel GRAPPA Reconstruction Algorithm to Accelerate 1H Magnetic Resonance Spectroscopic Imaging

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    Magnetic resonance spectroscopic imaging (MRSI) has the ability to noninvasively interrogate metabolism in vivo. However, excessively long scan times have thus far prevented its adoption into routine clinical practice. Generalized autocalibrating partially parallel acquisitions (GRAPPA) is a parallel imaging technique that allows one to reduce acquisition duration and use spatial sensitivity correlations to reconstruct the unsampled data points. The coil sensitivity weights are determined implicitly via a fully-sampled autocalibration region in k-space. In this dissertation, a novel GRAPPA-based algorithm is presented for the acceleration of 1H MRSI. Autocalibration Region extending Through Time (ARTT) GRAPPA instead extracts the coil weights from a region in k-t space, allowing for undersampling along each spatial dimension. This technique, by exploiting spatial-spectral correlations present in MRSI data, allows for a more accurate determination of the coil weights and subsequent parallel imaging reconstruction. This improved reconstruction accuracy can then be traded for more aggressive undersampling and a further reduction of acquisition duration. It is shown that the ARTT GRAPPA technique allows for approximately two-fold more aggressive undersampling than the conventional technique while achieving the same reconstruction accuracy. This accelerated protocol is then applied to acquire high-resolution brain metabolite maps in less than twenty minutes in three healthy volunteers at B0 = 7 T
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