662 research outputs found
Spin dynamics of a trapped spin-1 Bose Gas above the Bose-Einstein transition temperature
We study collective spin oscillations in a spin-1 Bose gas above the
Bose-Einstein transition temperature. Starting from the Heisenberg equation of
motion, we derive a kinetic equation describing the dynamics of a thermal gas
with the spin-1 degree of freedom. Applying the moment method to the kinetic
equation, we study spin-wave collective modes with dipole symmetry. The dipole
modes in the spin-1 system are found to be classified into the three type of
modes. The frequency and damping rate are obtained as functions of the peak
density. The damping rate is characterized by three relaxation times associated
with collisions.Comment: 19 pages, 5 figur
Charmless Exclusive Baryonic B Decays
We present a systematical study of two-body and three-body charmless baryonic
B decays. Branching ratios for two-body modes are in general very small,
typically less than , except that \B(B^-\to p \bar\Delta^{--})\sim
1\times 10^{-6}. In general, due to
the large coupling constant for . For three-body modes we
focus on octet baryon final states. The leading three-dominated modes are with a branching ratio of
order for and
for . The penguin-dominated decays with strangeness
in the meson, e.g., and , have appreciable rates and the mass
spectrum peaks at low mass. The penguin-dominated modes containing a strange
baryon, e.g., , have
branching ratios of order . In contrast, the decay
rate of is smaller. We explain why some of
charmless three-body final states in which baryon-antibaryon pair production is
accompanied by a meson have a larger rate than their two-body counterparts:
either the pole diagrams for the former have an anti-triplet bottom baryon
intermediate state, which has a large coupling to the meson and the
nucleon, or they are dominated by the factorizable external -emission
process.Comment: 46 pages and 3 figures, to appear in Phys. Rev. D. Major changes are:
(i) Calculations of two-body baryonic B decays involving a Delta resonance
are modified, and (ii) Penguin-dominated modes B-> Sigma+N(bar)+p are
discusse
Sudden switch of generalized Lieb-Robinson velocity in a transverse field Ising spin chain
The Lieb-Robinson theorem states that the speed at which the correlations
between two distant nodes in a spin network can be built through local
interactions has an upper bound, which is called the Lieb-Robinson velocity.
Our central aim is to demonstrate how to observe the Lieb-Robinson velocity in
an Ising spin chain with a strong transverse field. We adopt and compare four
correlation measures for characterizing different types of correlations, which
include correlation function, mutual information, quantum discord, and
entanglement of formation. We prove that one of correlation functions shows a
special behavior depending on the parity of the spin number. All the
information-theoretical correlation measures demonstrate the existence of the
Lieb-Robinson velocity. In particular, we find that there is a sudden switch of
the Lieb-Robinson speed with the increasing of the number of spin
Nonfactorizable contributions to decays
While the factorization assumption works well for many two-body nonleptonic
meson decay modes, the recent measurement of with
, and shows large deviation from this assumption. We
analyze the decays in the perturbative QCD approach based on
factorization theorem, in which both factorizable and nonfactorizable
contributions can be calculated in the same framework. Our predictions for the
Bauer-Stech-Wirbel parameters, and and and , are
consistent with the observed and branching ratios,
respectively. It is found that the large magnitude and the large
relative phase between and come from color-suppressed
nonfactorizable amplitudes. Our predictions for the , branching ratios can be confronted with
future experimental data.Comment: 25 pages with Latex, axodraw.sty, 6 figures and 5 tables, Version
published in PRD, Added new section 5 and reference
Search for Charmless Two-body Baryonic Decays of B Mesons
We report the results of a search for the rare baryonic decays , , and . The analysis
is based on a data set of events collected by the
Belle detector at the KEKB collider. No statistically significant
signals are found, and we set branching fraction upper limits , , and at the 90% confidence level.Comment: 6 pages, 4 figures and 1 table. Submitted to Phys. Rev. D Rapid
Communication
Influence of Bleeding Risk on Outcomes of Radial and Femoral Access for Percutaneous Coronary Intervention: An Analysis From the GLOBAL LEADERS Trial
Background: Radial artery access has been shown to reduce mortality and bleeding events, especially in patients with acute coronary syndromes. Despite this, interventional cardiologists experienced in femoral artery access still prefer that route for percutaneous coronary intervention. Little is known regarding the merits of each vascular access in patients stratified by their risk of bleeding. Methods: Patients from the Global Leaders trial were dichotomized into low or high risk of bleeding by the median of the PRECISE-DAPT score. Clinical outcomes were compared at 30 days. Results: In the overall population, there were no statistical differences between radial and femoral access in the rate of the primary end point, a composite of all-cause mortality, or new Q-wave myocardial infarction (MI) (hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.42-1.15). Radial access was associated with a significantly lower rate of the secondary safety end point, Bleeding Academic Research Consortium (BARC) 3 or 5 bleeding (HR 0.55, 95% CI 0.36-0.84). Compared by bleeding risk strata, in the high bleeding score population, the primary (HR 0.47, 95% CI 0.26-0.85; P = 0.012; Pinteraction = 0.019) and secondary safety (HR 0.57, 95% CI 0.35-0.95; P = 0.030; Pinteraction = 0.631) end points favoured radial access. In the low bleeding score population, however, the differences in the primary and secondary safety end points between radial and femoral artery access were no longer statistically significant. Conclusions: Our findings suggest that the outcomes of mortality or new Q-wave MI and BARC 3 or 5 bleeding favour radial access in patients with a high, but not those with a low, risk of bleeding. Because thisContexte : Il a et e d emontr e que l âaccès par lâartère radiale reduit la
mortalite et les h emorragies, en particulier chez les patients
presentant un syndrome coronarien aigu. Malgr e cela, les cardiologues
interventionnels qui ont acquis de lâexperience en matière d âaccès par
lâartère femorale pr efèrent encore utiliser cette voie lorsqu âils doivent
pratiquer une intervention coronarienne percutanee. On connaĂŽt mal lâinterĂŞt de chacune de ces techniques d âaccès vasculaire au regard du
risque dâhemorragie.
Methodologie : Les patients de lâessai GLOBAL LEADERS ont et e
repartis en deux groupes, selon qu âils presentaient un risque
dâhemorragie faible ou elev e d âaprès le score PRECISE-DAPT median,
puis les resultats cliniques ont et e compar es Ă 30 jours.
Resultats : Dans lâensemble de la population, aucune difference sta-
tistiquement significative nâa et e observ ee entre l âaccès radial et
lâaccès femoral quant au critère d âevaluation principal, compos e de la
mortalite toutes causes confondues et d âun nouvel infarctus du myocarde (IM) avec onde Q (rapport des risques instantanes [RRI] de 0,70;
intervalle de confiance [IC] Ă 95 % : 0,42-1,15). Lâaccès radial a et e
associe à un taux signi ficativement plus faible de survenue du critère
secondaire dâevaluation de l âinnocuite, c âest-Ă -dire une hemorragie de
type 3 ou 5 selon la classification du BARC (Bleeding Academic
Research Consortium) (RRI de 0,55; IC Ă 95 % : 0,36-0,84). Lorsquâon
compare les sujets en fonction du risque dâhemorragie, les critères
dâevaluation de l âinnocuite principal (RRI de 0,47; IC Ă 95 % : 0,26-
0,85; p Âź 0,012; pinteraction Âź 0,019) et secondaire (RRI de 0,57; IC Ă
95 % : 0,35-0,95; p Âź 0,030; pinteraction Âź 0,631) sont favorables Ă
lâaccès radial au sein de la population presentant un risque d âhemor-
ragie elev e. Dans la population pr esentant un risque d âhemorragie
faible, les differences entre l âaccès radial et lâaccès femoral quant aux
critères dâevaluation de l âinnocuite principal et secondaire ne sont
toutefois plus statistiquement significatives.
Conclusions : Selon ces observations, les resultats concernant la
mortalite ou la survenue d âun nouvel IM avec onde Q et le risque
dâhemorragie de type 3 ou 5 selon la classi fication du BARC indiquent
que lâaccès radial serait Ă privilegier lorsque le risque d âhemorragie est
elev e, mais pas lorsqu âil est faible. Comme il ne sâagissait pas dâune
analyse principale, il convient de considerer ces observations comme
etant g en eratrices d âhypothèses
Short Distance vs. Long Distance Physics: The Classical Limit of the Minimal Length Uncertainty Relation
We continue our investigation of the phenomenological implications of the
"deformed" commutation relations [x_i,p_j]=i hbar[(1 + beta p^2) delta_{ij} +
beta' p_i p_j]. These commutation relations are motivated by the fact that they
lead to the minimal length uncertainty relation which appears in perturbative
string theory. In this paper, we consider the effects of the deformation on the
classical orbits of particles in a central force potential. Comparison with
observation places severe constraints on the value of the minimum length.Comment: 20 pages REVTEX4, 4 color eps figures, typos correcte
At the edge of intonation: the interplay of utterance-final F0 movements and voiceless fricative sounds
The paper is concerned with the 'edge of intonation' in a twofold sense. It focuses on utterance-final F0 movements and crosses the traditional segment-prosody divide by investigating the interplay of F0 and voiceless fricatives in speech production. An experiment was performed for German with four types of voiceless fricatives: /f/, /s/, /Ę/ and /x/. They were elicited with scripted dialogues in the contexts of terminal falling statement and high rising question intonations. Acoustic analyses show that fricatives concluding the high rising question intonations had higher mean centres of gravity (CoGs), larger CoG ranges and higher noise energy levels than fricatives concluding the terminal falling statement intonations. The different spectral-energy patterns are suitable to induce percepts of a high 'aperiodic pitch' at the end of the questions and of a low 'aperiodic pitch' at the end of the statements. The results are discussed with regard to the possible existence of 'segmental intonation' and its implication for F0 truncation and the segment-prosody dichotomy, in which segments are the alleged troublemakers for the production and perception of intonation
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Single Spin Asymmetry in Polarized Proton-Proton Elastic Scattering at GeV
We report a high precision measurement of the transverse single spin
asymmetry at the center of mass energy GeV in elastic
proton-proton scattering by the STAR experiment at RHIC. The was measured
in the four-momentum transfer squared range \GeVcSq, the region of a significant interference between the
electromagnetic and hadronic scattering amplitudes. The measured values of
and its -dependence are consistent with a vanishing hadronic spin-flip
amplitude, thus providing strong constraints on the ratio of the single
spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated
by the Pomeron amplitude at this , we conclude that this measurement
addresses the question about the presence of a hadronic spin flip due to the
Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure
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