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

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 $\Delta$ induced by the application of a perpendicular electric field. We calculate the crossover chemical potential, $\Delta_{\rm cr}$, 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 $\Delta_{\rm cr}<<\Delta$. The huge suppression of $\Delta_{\rm cr}$ compared with $\Delta$ provides a possible explanation for the large difference between the theoretical band gap $\Delta$ and the experimentally extracted transport gap.Comment: 5 Pages, 2 figures. Published versio

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

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

No Escape

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 concrète 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

Inhomogeneity and nonlinear screening in gapped bilayer graphene

We demonstrate that for gapped bilayer graphene, the nonlinear nature of the screening of an external disorder potential and the resulting inhomogeneity of the electron liquid are crucial for describing the electronic compressibility. In particular, traditional diagrammatic methods of many-body theory do not include this inhomogeneity and therefore fail to reproduce experimental data accurately, particularly at low carrier densities. In contrast, a direct calculation of the charge landscape via a numerical Thomas-Fermi energy functional method along with the appropriate bulk averaging procedure captures all the essential physics, including the interplay between the band gap and the inhomogeneity.Comment: 7 pages, 5 figures. Please note, the visual quality of Fig. 3 has been reduced to accommodate arXiv's total size requirement for submissions. Full quality figures are available in the published versio

Extension of the C star rotation curve of the Milky Way to 24 kpc

Demers and Battinelli published, in 2007 the rotation curve of the Milky Way based on the radial velocity of carbon stars outside the Solar circle. Since then we have established a new list of candidates for spectroscopy. The goal of this paper is to determine the rotation curve of the galaxy, as far as possible from the galactic center, using N type carbon stars. The stars were selected from their dereddened 2MASS colours, then the spectra were obtained with the Dominion Astrophysical Observatory and Asiago 1.8 meter telescopes. This publication adds radial velocities and Galactrocentric distances of 36 carbon stars, from which 20 are new confirmed. The new results for stars up to 25 kpc from the galactic center, suggest that the rotation curve shows a slight decline beyond the Solar circle.Comment: 13 pages, 3 figures, 1 table; accepted for publication in Astrophysic

Two-dimensional electronic transport on the surface of 3D topological insulators

We present a theoretical approach to describe the 2D transport properties of the surfaces of three dimensional topological insulators (3DTIs) including disorder and phonon scattering effects. The method that we present is able to take into account the effects of the strong disorder-induced carrier density inhomogeneities that characterize the ground state of the surface of 3DTIs, especially at low doping, as recently shown experimentally. Due to the inhomogeneous nature of the carrier density landscape, standard theoretical techniques based on ensemble averaging over disorder assuming a spatially uniform average carrier density are inadequate. Moreover the presence of strong spatial potential and density fluctuations greatly enhance the effect of thermally activated processes on the transport properties. The theory presented is able to take into account all the effects due to the disorder-induced inhomogeneities, momentum scattering by disorder, and the effect of electron-phonon scattering processes. As a result the developed theory is able to accurately describe the transport properties of the surfaces of 3DTIs both at zero and finite temperature.Comment: 14 pages, 18 figure

Spontaneous interlayer superfluidity in bilayer systems of cold polar molecules

Quantum degenerate cold-atom gases provide a remarkable opportunity to study strongly interacting systems. Recent experimental progress in producing ultracold polar molecules with a net electric dipole moment opens up new possibilities to realize novel quantum phases governed by the long-range and anisotropic dipole-dipole interactions. In this work we predict the existence of experimentally observable novel broken-symmetry states with spontaneous interlayer coherence in cold polar molecules. These exotic states appear due to strong repulsive interlayer interactions and exhibit properties of superfluids, ferromagnets and excitonic condensates.Comment: 7 pages, 5 figures, final versio