45,486 research outputs found

    Translational perspectives on perfusion-diffusion mismatch in ischemic stroke

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    Magnetic resonance imaging has tremendous potential to illuminate ischemic stroke pathophysiology and guide rational treatment decisions. Clinical applications to date have been largely limited to trials. However, recent analyses of the major clinical studies have led to refinements in selection criteria and improved understanding of the potential implications for the risk vs. benefit of thrombolytic therapy. In parallel, preclinical studies have provided complementary information on the evolution of stroke that is difficult to obtain in humans due to the requirement for continuous or repeated imaging and pathological verification. We review the clinical and preclinical advances that have led to perfusion–diffusion mismatch being applied in phase 3 randomized trials and, potentially, future routine clinical practice

    Field Effect Transistors on Rubrene Single Crystals with Parylene Gate Insulator

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    We report on fabrication and characterization of the organic field effect transistors (OFETs) on the surface of single crystals of rubrene. The parylene polymer film has been used as the gate insulator. At room temperature, these OFETs exhibit the p-type conductivity with the field effect mobility up to 1 cm^2/Vs and the on/off ratio ~ 10^4. The temperature dependence of the mobility is discussed.Comment: 3 page

    Using Pinch Gloves(TM) for both Natural and Abstract Interaction Techniques in Virtual Environments

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    Usable three-dimensional (3D) interaction techniques are difficult to design, implement, and evaluate. One reason for this is a poor understanding of the advantages and disadvantages of the wide range of 3D input devices, and of the mapping between input devices and interaction techniques. We present an analysis of Pinch Gloves™ and their use as input devices for virtual environments (VEs). We have developed a number of novel and usable interaction techniques for VEs using the gloves, including a menu system, a technique for text input, and a two-handed navigation technique. User studies have indicated the usability and utility of these techniques

    Sudden Expansion of a One-Dimensional Bose Gas from Power-Law Traps

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    We analyze free expansion of a trapped one-dimensional Bose gas after a sudden release from the confining trap potential. By using the stationary phase and local density approximations, we show that the long-time asymptotic density profile and the momentum distribution of the gas are determined by the initial distribution of Bethe rapidities (quasimomenta) and hence can be obtained from the solutions to the Lieb-Liniger equations in the thermodynamic limit. For expansion from a harmonic trap, and in the limits of very weak and very strong interactions, we recover the self-similar scaling solutions known from the hydrodynamic approach. For all other power-law traps and arbitrary interaction strengths, the expansion is not self-similar and shows strong dependence of the density profile evolution on the trap anharmonicity. We also characterize dynamical fermionization of the expanding cloud in terms of correlation functions describing phase and density fluctuations.Comment: Final published version with modified title and a couple of other minor changes. 5 pages, 2 figures, and Supplemental Materia

    The impact of evolving labor practices and demographics on U.S. inflation and unemployment

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    Since the early 1990s, NAIRU estimates have declined and unemployment duration has risen relative to the unemployment rate. These developments may have arisen from the aging of the workforce or practices reducing job turnover. We assess the internal consistency of these hypotheses using simulation methods and test their external consistency using modified NAIRU models. We find that demographics cannot fully account for changes in the NAIRU, consistent with Staiger, Stock, and Watson (2001) and in contrast to Shimer (1998, 2001). Instead, our results attribute shifts in the NAIRU and duration to a combination of shifts in demographics and job turnover.

    Reducing driver distraction by utilizing augmented reality head-up display system for rear passengers

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    Kinetics of viral self-assembly: the role of ss RNA antenna

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    A big class of viruses self-assemble from a large number of identical capsid proteins with long flexible N-terminal tails and ss RNA. We study the role of the strong Coulomb interaction of positive N-terminal tails with ss RNA in the kinetics of the in vitro virus self-assembly. Capsid proteins stick to unassembled chain of ss RNA (which we call "antenna") and slide on it towards the assembly site. We show that at excess of capsid proteins such one-dimensional diffusion accelerates self-assembly more than ten times. On the other hand at excess of ss RNA, antenna slows self-assembly down. Several experiments are proposed to verify the role of ss RNA antenna.Comment: 4 pages, 3 figures, several experiments are proposed, a new idea of experiment is adde

    Flux Penetration in Superconducting Strip with Edge-Indentation

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    The flux penetration near a semicircular indentation at the edge of a thin superconducting strip placed in a transverse magnetic field is investigated. The flux front distortion due to the indentation is calculated numerically by solving the Maxwell equations with a highly nonlinear E(j)E(j) law. We find that the excess penetration, Δ\Delta, can be significantly (\sim 50%) larger than the indentation radius r0r_0, in contrast to a bulk supercondutor in the critical state where Δ=r0\Delta=r_0. It is also shown that the flux creep tends to smoothen the flux front, i.e. reduce Δ\Delta. The results are in very good agreement with magneto-optical studies of flux penetration into an YBa2_2Cu3_3Ox_x film having an edge defect.Comment: 5 pages, 7 figure
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