438 research outputs found

    Search for light-speed anisotropies using Compton scattering of high-energy electrons

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    Based on the high sensitivity of Compton scattering off ultra relativistic electrons, the possibility of anisotropies in the speed of light is investigated. The result discussed in this contribution is based on the gamma-ray beam of the ESRF's GRAAL facility (Grenoble, France) and the search for sidereal variations in the energy of the Compton-edge photons. The absence of oscillations yields the two-sided limit of 1.6 x 10^{-14} at 95 % confidence level on a combination of photon and electron coefficients of the minimal Standard Model Extension (mSME). This new constraint provides an improvement over previous bounds by one order of magnitude.Comment: Talk presented at the Fifth Meeting on CPT and Lorentz Symmetry, University of Indiana, June 28-July 2, 201

    Gravitational resonance spectroscopy with an oscillating magnetic field gradient in the GRANIT flow through arrangement

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    Gravitational resonance spectroscopy consists in measuring the energy spectrum of bouncing ultracold neutrons above a mirror by inducing resonant transitions between different discrete quantum levels. We discuss how to induce the resonances with a flow through arrangement in the GRANIT spectrometer, excited by an oscillating magnetic field gradient. The spectroscopy could be realized in two distinct modes (so called DC and AC) using the same device to produce the magnetic excitation. We present calculations demonstrating the feasibility of the newly proposed AC mode

    Scheduling multiprocessor tasks with genetic algorithms

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    In the multĂ­processor schedulĂ­ng problem a given program is to be scheduled in a given multiprocessor system such that the program 's execution time is minimized. This problem being very hard to solve exactly, many heuristic methods for finding a suboptimal schedule exist. We propose a new combined approach, where a genetic algorithm is improved with the introduction of some knowledge about the scheduling problem represented by the use of a list heuristic in the crossover and mutatĂ­on genetic operations. This knowledge-augmented genetic approach is empirically compared with a "pure" genetic algorithm and with a "pure" list heuristic, both from the literature. Results of the experiments carried out with synthetic instances of the scheduling problem show that our knowledge-augmented algorithm produces much better results in terms of quality of solutions, although being slower in terms of execution time

    Frequency shifts in gravitational resonance spectroscopy

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    Quantum states of ultracold neutrons in the gravitational field are to be characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts, which we call Stern-Gerlach shift, interference shift, and spectator state shift, appear in conceivable measurement schemes and have general importance. These shifts have to be taken into account in precision experiments

    Une « femme libérée » ?

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    NĂ©e en 1943 Ă  Alger, AndrĂ©e Job-Querzola poursuit des Ă©tudes de lettres Ă  Aix-en-Provence puis Ă  Paris dans les annĂ©es 1960. Devenue enseignante, elle gravite dans la mouvance fĂ©ministe et d’extrĂȘme gauche et participe activement aux Ă©vĂ©nements de Mai. MarquĂ©e par les luttes fĂ©ministes des annĂ©es 1970, en particulier celles du MLF, du MLAC, du MFPF, elle souhaite rendre hommage aux femmes de sa gĂ©nĂ©ration – « une gĂ©nĂ©ration rebelle » qui, selon elle, sonne le glas de « gĂ©nĂ©rations de femmes f..

    Raphaëlle Branche & Fabrice Virgili (dir.), Viols en temps de guerre

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    Issu d’un colloque qui a rĂ©uni en 2009 de nombreux chercheuses et chercheurs en sciences humaines (anthropologie, sociologie, histoire, philosophie, droit
), ce livre s’empare d’un sujet assez peu Ă©tudiĂ© jusqu’ici dans l’histoire des guerres : les viols. DĂšs l’introduction, RaphaĂ«lle Branche et Fabrice Virgili soulignent qu’il n’est pas facile de nommer l’acte du viol (qui peut se classer dans un vaste rĂ©pertoire de violences sexuelles) ni de le comptabiliser en raison des lacunes persistante..

    Représentations des intimités amoureuses dans la France du xxe siÚcle

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    Cet article aborde la question de la façon dont on peut Ă©crire une histoire de l’intimitĂ©, en se concentrant sur le xxe siĂšcle et en se basant sur de nouvelles sources : les archives autobiographiques (les journaux intimes, les histoires autobiographiques et la correspondance). Comment les individus ont-ils imaginĂ© leurs pratiques amoureuses et quel sens avaient-elles ? Le domaine de l’intimitĂ© reste en retrait pendant la pĂ©riode de l’entre-deux-guerres, il est remis en question entre 1939 et 1965 et se retrouve finalement exposĂ© au grand jour pendant la pĂ©riode de mai 1968 (de 1965 Ă  1975).This article addresses the question as how to write a history of intimacy, focusing on the twentieth century and based on new sources: autobiographical archives (personal diaries, autobiographical stories and correspondence). How did individuals imagine their amorous practices and what meaning did they hold? The realm of intimacy remains subdued during the interwar period, challenged during 1939-1965 and finally brought out into the open during the May’ 68 period (1965-1975)

    DeconstrucciĂłn del realismo. Paradojas de la metĂĄfora del teatro en "El vano ayer" de Isaac Rosa

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    Estudiamos un relato que piensa y deconstruye los modos realistas de la novela de la memoria en España, a partir del anålisis de la metåfora del espectåculo teatral proteiforme y omnipresente en "El vano ayer" de Isaac Rosa, dialogando con el artículo de G. Champeau en esta revista. Exploramos las pistas de la categoría crítica de los "nuevos realismos" con una metåfora que asume un complejo gesto polémico y renovador en la obra: el vínculo entre este "nuevo" realismo y la escritura de la memoria; la renovación que emprende "El vano ayer" de la concepción de la mimesis; y la relación con la genealogía realista heredada de la historia de la literatura española. La metåfora del teatro serå a la vez, en su modalidad degradada de la farsa, lo que plasma los fallos del discurso realista actual para contar el pasado, mientras que en su versión mås reflexiva, brechtiana, busca exhibir la construcción del discurso y de los imaginarios sociales

    Marie-Carmen Garcia, Amours clandestines. Sociologie de l’extraconjugalitĂ© durable

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    « Les relations extraconjugales qui durent constituent une Ă©nigme qui dĂ©range Ă  la fois les normes conjugales, les normes amoureuses et les normes qui rĂ©gissent la masculinitĂ© et la fĂ©minité » (p. 27). C’est sur cette Ă©nigme que se penche la sociologue Marie-Carmen Garcia, dĂ©sireuse de traiter un sujet peu abordĂ© en sociologie, soit parce qu’il reste sous le sceau du secret de la part des intĂ©ressĂ©s, soit par qu’il est jugĂ© lĂ©gĂšrement frivole, voire totalement inconvenant par les chercheuses ..
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