5,136 research outputs found
Neutrino Oscillations in Intermediate States.II -- Wave Packets
We analyze oscillations of intermediate neutrinos in terms of the scattering
of particles described by Gaussian wave packets. We study a scalar model as in
a previous paper (I) but in realistic situations, where the two particles of
the initial state and final state are wave packets and neutrinos are in the
intermediate state. The oscillation of the intermediate neutrino is found from
the time evolution of the total transition probability between the initial
state and final state. The effect of a finite lifetime and a finite relaxation
time are also studied. We find that the oscillation pattern depends on the
magnitude of wave packet sizes of particles in the initial state and final
state and the lifetime of the initial particle. For eV, the oscillation probability deviates from that of the standard
formula if the wave packet sizes are around m for 0.4 MeV neutrino.Comment: 29 pages, 11 figures. typos corrected, appendix adde
Ion-Ion Correlation Effect on the Neutrino-Nucleus Scattering in Supernova Cores
We calculate the ion-ion correlation effect on the neutrino-nucleus
scattering in supernova cores, which is an important opacity source for the
neutrinos and plays a vital role in the supernova explosion. In order to
calculate the ion-ion correlation effect we use the results of the improved
hypernetted-chain method calculations of the classical one-component plasma. As
in the preceding studies on this effect, we find a dramatic decrease of the
effective neutrino-nucleus scattering cross section for relatively low energy
neutrinos with E < 20MeV. As a matter of fact, our calculation shows a much
more dramatic reduction of the effective neutrino-nucleus scattering cross
section for the low energy neutrinos with E < 10MeV than the results of
Horowitz. Therefore, the ion-ion correlation effect will be more important than
has hitherto been recognized. We present an accurate analytic fitting formula
that summarizes our numerical results. This fitting formula will facilitate the
application of the present results to the supernova explosion simulations.Comment: 10 pages, 2 figures, 1 subroutine, published in ApJ 611, 1041-1044
(2004
Word Familiarity Rate Estimation Using a Bayesian Linear Mixed Model
National Institute for Japanese Language and LinguisticsThis paper presents research on word familiarity rate estimation using the \u27Word List by Semantic Principles\u27. We collected rating information on 96,557 words in the \u27Word List by Semantic Principles\u27 via Yahoo! crowdsourcing . We asked 3,392 subject participants to use their introspection to rate the familiarity of words based on the five perspectives of \u27KNOW\u27, \u27WRITE\u27, \u27READ\u27, \u27SPEAK\u27, and \u27LISTEN\u27, and each word was rated by at least 16 subject participants. We used Bayesian linear mixed models to estimate the word familiarity rates. We also explored the ratings with the semantic labels used in the \u27Word List by Semantic Principles\u27
Histone Acetylation Influences the Activity of Sox9-related Transcriptional Complex
Chondrocyte differentiation is the fundamental process in skeletal development. From the mesenchymal condensation of chondroprogenitors to the hypertrophic maturation of chondrocytes, chondrogenesis is sequentially regulated by cross-talk among transcription factors, growth factors, and chromatin structure. The master transcription factor Sry-type HMG box (Sox) 9 has an essential role in the expression of chondrogenic genes through the association with Sox9-binding sites on its target genes. Several transcription factors and coactivators, such as Scleraxis/E47 and p300, cooperatively modulate the Sox9-dependent transcription by interacting with Sox9. The Sox9-related transcriptional apparatus activates its target gene expression through p300-mediated histone acetylation on chromatin. The transforming growth factor (TGF)-β superfamily also plays a key role in chondrocyte differentiation. The TGF-β-regulated Smad3/4 complex activates Sox9-dependent transcription on chromatin by associating with Sox9 itself, and by recruiting p300 onto Sox9. These findings suggest that the epigenetic status including histone modification and chromatin structure, directly influences Sox9-regulated chondrocyte differentiation. In this article, we review the regulators of Sox9 expression itself, modulators of posttranslational Sox9 function, and Sox9-associating factors in the Sox9-dependent epigenetic regulation during chondrogenesis
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