58,982 research outputs found

    Inhomogenous electronic structure, transport gap, and percolation threshold in disordered bilayer graphene

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    The inhomogenous real-space electronic structure of gapless and gapped disordered bilayer graphene is calculated in the presence of quenched charge impurities. For gapped bilayer graphene we find that for current experimental conditions the amplitude of the fluctuations of the screened disorder potential is of the order of (or often larger than) the intrinsic gap Δ\Delta induced by the application of a perpendicular electric field. We calculate the crossover chemical potential, Δcr\Delta_{\rm cr}, separating the insulating regime from a percolative regime in which less than half of the area of the bilayer graphene sample is insulating. We find that most of the current experiments are in the percolative regime with Δcr<<Δ\Delta_{\rm cr}<<\Delta. The huge suppression of Δcr\Delta_{\rm cr} compared with Δ\Delta provides a possible explanation for the large difference between the theoretical band gap Δ\Delta and the experimentally extracted transport gap.Comment: 5 Pages, 2 figures. Published versio

    No Escape

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    The initial idea for the film came from an inspiring performance of Chaplin's Easy Street (1917) accompanied by Donald MacKenzie, resident organist at the Odeon Leicester Square, which led me into researches of early cinema (c1895-1907), a period described by Tom Gunning as the ‘cinema of attractions’. James Lastra points out that during this time competition between cinemas was based on the success of various sound strategies all emphasising the ‘liveness’ of the film experience and films were made to motivate particular types of sound accompaniment. Particularly intriguing was the use of live sound effects performed by a skilled troupe from behind the film screen to produce ‘realistic’ sound effects. This is translated in No Escape into the manipulation of on-screen diegetic sound, also inspired by Pierre Schaeffer's musique concrùte and his notions of the sound object and reduced listening. The interaction between the live piano and the onscreen sound is crucial to No Escape as is that of the piano and images, which exist alone together for long stretches. The visual content and structure of the film draws on the city symphonies of Walter Ruttman and especially Dziga Vertov whose formal experimentation, startling juxtaposition of images and very rapid editing is important to No Escape’s non-narrative and at times complex montage of British rural and urban vistas. Vertov’s Man with a Movie Camera (1929) is by and partially about the man with the camera as is No Escape, the title of which refers to the idea that though we may travel to get away from something, there is no escape from the inner life. This is represented by the piano music, which varies but within fairly restricted limits. It does respond or drive image choice and editing but the overall sense should be that one cannot escape and these responses are temporary and fleeting Extrapolating from Tom Gunning's cinema of attractions, James Beattie's concept of ‘documentary display’ - a poetic, sensual and subjective approach which encourages listening and looking rather than cognitive understanding - underpins the aesthetic of No Escape, as is a belief in the supremacy of sound and of film as a performative event

    Involvement of leukotriene pathway in the pathogenesis of ischemia-reperfusion injury and septic and non-septic shock.

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    The 5-lipoxygenase (5-LO) pathway is responsible for the production of leukotrienes (LTs), inflammatory lipid mediators which play a role in innate immunity. More recently, a pivotal role of LTs in ischemia-reperfusion and shock injury has been suggested. In fact, these pathological conditions are characterized by a severe neutrophil infiltration that gives rise to tissue injury and 5-LO metabolites control neutrophil recruitment in injured tissue by the modulation of adhesion molecule expression. The aim of this review is to analyze the results reported in the literature on the role of 5-LO pathway, with particular regard to LTs, in these pathological conditions. A better understanding of the mechanisms underlying the role of the 5-LO enzyme and/or its metabolites in the regulation of neutrophil trafficking, might open new perspectives in the therapy of organ dysfunction and/or injury associated with shock and ischemia-reperfusion injury

    An air core quadrupole for the PIMMS synchrotron

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