30,765 research outputs found
WCDMA Uplink Capacity of a Long Tunnel Cigar-shaped Microcells for Underground Train Service
In this paper, the capacity and the interference statistics of the sectors of the cigar-shaped WCDMA microcells are studied using the hybrid model of propagation. A model of nine microcells in a metro tunnel is used to analyze the uplink capacity and the interference statistics. The capacity and the interference statistics of the microcells in metro tunnels are studied in this work for different propagation parameters, antenna side lobe levels, sector ranges and bends losses
Glucocorticoids for human skin: New aspects of the mechanism of action
Topical glucocorticoids have always been considered first-line drugs for inflammatory diseases of the skin and bronchial system. Applied systemically, glucocorticoids are used for severe inflammatory and immunological diseases and the inhibition of transplant rejection. Owing to the progress in molecular pharmacology, the knowledge of the mechanism of action has increased during the last years. Besides distinct genomic targets, which are due to the activation of specific cytoplasmatic receptors resulting in the (trans-) activation or (trans-) repression of target genes, there are non-genomic effects on the basis of the interference with membrane-associated receptors as well as with membrane lipids. In fact, various glucocorticoids appear to differ with respect to the relative influence on these targets. Thus, the extended knowledge of glucocorticoid-induced cellular signalling should allow the design and development of even more specifically acting drugs-as it has been obtained with other steroids, e.g. estrogens for osteoporosis prevention. Copyright (C) 2005 S. Karger AG, Basel
A proposal for testing Quantum Gravity in the lab
Attempts to formulate a quantum theory of gravitation are collectively known
as {\it quantum gravity}. Various approaches to quantum gravity such as string
theory and loop quantum gravity, as well as black hole physics and doubly
special relativity theories predict a minimum measurable length, or a maximum
observable momentum, and related modifications of the Heisenberg Uncertainty
Principle to a so-called generalized uncertainty principle (GUP). We have
proposed a GUP consistent with string theory, black hole physics and doubly
special relativity theories and have showed that this modifies all quantum
mechanical Hamiltonians. When applied to an elementary particle, it suggests
that the space that confines it must be quantized, and in fact that all
measurable lengths are quantized in units of a fundamental length (which can be
the Planck length). On the one hand, this may signal the breakdown of the
spacetime continuum picture near that scale, and on the other hand, it can
predict an upper bound on the quantum gravity parameter in the GUP, from
current observations. Furthermore, such fundamental discreteness of space may
have observable consequences at length scales much larger than the Planck
scale. Because this influences all the quantum Hamiltonians in an universal
way, it predicts quantum gravity corrections to various quantum phenomena.
Therefore, in the present work we compute these corrections to the Lamb shift,
simple harmonic oscillator, Landau levels, and the tunneling current in a
scanning tunneling microscope.Comment: v1: 10 pages, REVTeX 4, no figures; v2: minor typos corrected and a
reference added. arXiv admin note: has substantial overlap with
arXiv:0906.5396 , published in a different journa
Contribution of memory evaluation in temporal epilepsy surgery
Memory assessment is a crucial step in the pre-surgical assessment of temporal epilepsy. Indeed, it participates to a certain extent in the process of localization of the epileptogenic zone and also makes it possible to anticipate the possible risks of surgical treatment on the memory.We propose to specify the contribution of memory evaluation in 60 patients’ candidates for temporal epilepsy surgery, in terms of localization of the “epileptogenic zone” and in the appreciation of the risk of postoperative memory decline
Status of BetaCage: an Ultra-sensitive Screener for Surface Contamination
BetaCage, a gaseous neon time-projection chamber, has been proposed as a viable screener for emitters of low-energy alphas and electrons to which commercial radioactivity counting techniques are insensitive. Using radiopure materials for construction, active and passive shielding from extrinsic backgrounds, large counting area and minimal detector mass, BetaCage will be able to achieve sensitivities of 10^(−5) counts keV^(−1) kg^(−1) day^(−1) in a few days of running time. We report on progress in prototype development work since the last meeting of this workshop
- …