2,679 research outputs found
Quantum Black Hole Wave Packet: Average Area Entropy and Temperature Dependent Width
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 average, leaving the 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
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
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?
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
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 -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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