2,679 research outputs found

    Quantum Black Hole Wave Packet: Average Area Entropy and Temperature Dependent Width

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    A quantum Schwarzschild black hole is described, at the mini super spacetime level, by a non-singular wave packet composed of plane wave eigenstates of the momentum Dirac-conjugate to the mass operator. The entropy of the mass spectrum acquires then independent contributions from the average mass and the width. Hence, Bekenstein's area entropy is formulated using the ⟨mass2⟩\langle \text{mass}^2 \rangle average, leaving the ⟨mass⟩\langle \text{mass} \rangle average to set the Hawking temperature. The width function peaks at the Planck scale for an elementary (zero entropy, zero free energy) micro black hole of finite rms size, and decreases Doppler-like towards the classical limit.Comment: 5 PRD pages, 1 figure; v.2 minor typo correction

    Until Justice Be Done: America’s First Civil Rights Movement, From the Revolution to Reconstruction

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    Masur contends historians have overlooked a decades’-long, Black-led civil rights movement that flourished in the nineteenth century. Until Justice Be Done is necessary reading for any scholar of U.S. history,” and is a book that should receive a wide readership beyond academia,” as Masur’s “non-polemical” examination of citizenship rights “may well challenge those of various political stripes to reexamine their idea and strategies for honoring, changing, or using the Constitution.

    Measurement of Dicke Narrowing in Electromagnetically Induced Transparency

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    Dicke narrowing is a phenomena that dramatically reduces the Doppler width of spectral lines, due to frequent velocity-changing collisions. A similar phenomena occurs for electromagnetically induced transparency (EIT) resonances, and facilitates ultra-narrow spectral features in room-temperature vapor. We directly measure the Dicke-like narrowing by studying EIT line-shapes as a function of the angle between the pump and the probe beams. The measurements are in good agreement with an analytic theory with no fit parameters. The results show that Dicke narrowing can increase substantially the tolerance of hot-vapor EIT to angular deviations. We demonstrate the importance of this effect for applications such as imaging and spatial solitons using a single-shot imaging experiment, and discuss the implications on the feasibility of storing images in atomic vapor.Comment: Introduction revise

    PI3 Kinase Activation and Response to Trastuzumab Therapy: What's neu with Herceptin Resistance?

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    Trastuzumab is an established therapy for women with breast cancers that overexpress HER2. Despite its proven benefit in treating breast cancer, not all women derive benefit from this monoclonal antibody, and resistant disease can develop. In this issue of Cancer Cell, Berns et al. present evidence that activation of the PI3 kinase pathway, either via loss of the tumor suppressor PTEN or through oncogenic stimulation of PIK3CA, can mediate trastuzumab resistance. This study extends important work of others and forms the rationale for future investigations combining inhibitors of the PI3 kinase pathway in conjunction with trastuzumab therapy

    On perturbations of continuous structures

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    We give a general framework for the treatment of perturbations of types and structures in continuous logic, allowing to specify which parts of the logic may be perturbed. We prove that separable, elementarily equivalent structures which are approximately ℵ0\aleph_0-saturated up to arbitrarily small perturbations are isomorphic up to arbitrarily small perturbations (where the notion of perturbation is part of the data). As a corollary, we obtain a Ryll-Nardzewski style characterisation of complete theories all of whose separable models are isomorphic up to arbitrarily small perturbations
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