8,022 research outputs found
Radiative and Electroweak Rare B Decays
This report summarizes the latest experimental results on radiative and
electroweak rare B meson decays. These rare decay processes proceed through the
flavor changing neutral current processes, and thus sensitive to the postulated
new particles in the theories beyond the Standard Model. Experiments at e+ e-
colliders, Belle, BaBar and CLEO, have been playing the dominant role, while
the CDF and D0 experiments have just started to provide new results from
Tevatron Run-II. The most significant achievement is the first observation of
the decay B --> K* l+ l-, which opens a new window to search for new physics in
B meson decays.Comment: To appear in Proceedings of the XXI International Symposium on Lepton
and Photon Interactions at High Energies, Fermilab, August 200
Large-scale analysis of human alternative protein isoforms: pattern classification and correlation with subcellular localization signals
We investigated human alternative protein isoforms of >2600 genes based on full-length cDNA clones and SwissProt. We classified the isoforms and examined their co-occurrence for each gene. Further, we investigated potential relationships between these changes and differential subcellular localization. The two most abundant patterns were the one with different C-terminal regions and the one with an internal insertion, which together account for 43% of the total. Although changes of the N-terminal region are less common than those of the C-terminal region, extension of the C-terminal region is much less common than that of the N-terminal region, probably because of the difficulty of removing stop codons in one isoform. We also found that there are some frequently used combinations of co-occurrence in alternative isoforms. We interpret this as evidence that there is some structural relationship which produces a repertoire of isoformal patterns. Finally, many terminal changes are predicted to cause differential subcellular localization, especially in targeting either peroxisomes or mitochondria. Our study sheds new light on the enrichment of the human proteome through alternative splicing and related events. Our database of alternative protein isoforms is available through the internet
Noise-Induced Synchronization and Clustering in Ensembles of Uncoupled Limit-Cycle Oscillators
We study synchronization properties of general uncoupled limit-cycle
oscillators driven by common and independent Gaussian white noises. Using phase
reduction and averaging methods, we analytically derive the stationary
distribution of the phase difference between oscillators for weak noise
intensity. We demonstrate that in addition to synchronization, clustering, or
more generally coherence, always results from arbitrary initial conditions,
irrespective of the details of the oscillators.Comment: 6 pages, 2 figure
Constitutional Law: Gag Me with a Prior Restraint: A Chilling Effect that Sends Shivers down the Spines of Attorneys and the Media
Black Strings in Our World
The brane world scenario is a new approach to resolve the problem on how to
compactify the higher dimensional spacetime to our 4-dimensional world. One of
the remarkable features of this scenario is the higher dimensional effects in
classical gravitational interactions at short distances. Due to this feature,
there are black string solutions in our 4-dimensional world. In this paper,
assuming the simplest model of complex minimally coupled scalar field with the
local U(1) symmetry, we show a possibility of black-string formation by merging
processes of type I long cosmic strings in our 4-dimensional world. No fine
tuning for the parameters in the model might be necessary.Comment: 11pages, no figur
On the enhancement of nuclear reaction rates in high-temperature plasma
We argue that the Maxwellian approximation can essentially underestimate the
rates of some nuclear reactions in hot plasma under conditions very close to
thermal equilibrium. This phenomenon is demonstrated explicitly on the example
of reactions in self-sustained DT fusion plasma with admixture of light
elements X = Li, Be, C. A kinetic analysis shows that the reactivity
enhancement results from non-Maxwellian knock-on perturbations of ion
distributions caused by close collisions with energetic fusion products. It is
found that although the fraction of the knock-on ions is small, these particles
appreciably affect the D+X and T+X reaction rates. The phenomenon discussed is
likely to have general nature and can play role in other laboratory and
probably astrophysical plasma processes.Comment: 12 pages, 4 figures, to be published in Phys. Lett.
STS Observations of Landau Levels at Graphite Surfaces
Scanning tunneling spectroscopy measurements were made on surfaces of two
different kinds of graphite samples, Kish graphite and highly oriented
pyrolytic graphite (HOPG), at very low temperatures and in high magnetic
fields. We observed a series of peaks in the tunnel spectra, which grow with
increasing field, both at positive and negative bias voltages. These are
associated with Landau quantization of the quasi two-dimensional electrons and
holes in graphite in magnetic fields perpendicular to the basal plane. Almost
field independent Landau levels fixed near the Fermi energy, which are
characteristic of the graphite crystalline structure, were directly observed
for the first time. Calculations of the local density of states at the graphite
surfaces allow us to identify Kish graphite as bulk graphite and HOPG as
graphite with finite thickness effectively
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