3,002 research outputs found
Search for B0(s) ---> mu+ mu- and B0(d) ---> mu+ mu- decays in p anti-p collisions at s**(1/2) = 1.96-TeV
We report on a search for Bs0→μ+μ- and Bd0→μ+μ- decays in pp̅ collisions at √s=1.96  TeV using 171  pb-1 of data collected by the CDF II experiment at the Fermilab Tevatron Collider. The decay rates of these rare processes are sensitive to contributions from physics beyond the standard model. One event survives all our selection requirements, consistent with the background expectation. We derive branching ratio limits of B(Bs0→μ+μ-)<5.8×10-7 and B(Bd0→μ+μ-)<1.5×10-7 at 90% confidence level
Walking in the High-rise City: A Health Enhancement and Pedometer-determined Ambulatory (HEPA) Program in Hong Kong
published_or_final_versio
Walking in the cement forest: a health enhancement and pedometer-determined ambulatory (HEPA) program in Hong Kong
Congress Theme: A Celebration of Diversity and Inclusion in Active AgeingThis journal suppl.entitled: Supplement issue: Abstracts for the 8th World Congress on Ageing and Physical Activitypublished_or_final_versionThe 8th Annual World Congress on Active Ageing (WCAA): A Celebration of Diversity and Inclusion in Active Ageing, Glasgow, Scotland, UK, 13 -17 August 2012. In Journal of Aging and Physical Activity, 2012, v. 20, Suppl., p. S226-S22
Relations Between Closed String Amplitudes at Higher-order Tree Level and Open String Amplitudes
KLT relations almost factorize closed string amplitudes on by two open
string tree amplitudes which correspond to the left- and the right- moving
sectors. In this paper, we investigate string amplitudes on and .
We find that KLT factorization relations do not hold in these two cases. The
relations between closed and open string amplitudes have new forms. On
and , the left- and the right- moving sectors are connected into a single
sector. Then an amplitude with closed strings on or can be given
by one open string tree amplitude except for a phase factor. The relations
depends on the topologies of the world-sheets.Under T-duality, the relations on
and give the amplitudes between closed strings scattering from
D-brane and O-plane respectively by open string partial amplitudes.In the low
energy limits of these two cases, the factorization relations for graviton
amplitudes do not hold. The amplitudes for gravitons must be given by the new
relations instead.Comment: 19 page
Recent advances in bibliometric indexes and the PaperRank problem
Bibliometric indexes are customary used in evaluating the impact of
scientific research, even though it is very well known that in different
research areas they may range in very different intervals. Sometimes, this is
evident even within a single given field of investigation making very difficult
(and inaccurate) the assessment of scientific papers. On the other hand, the
problem can be recast in the same framework which has allowed to efficiently
cope with the ordering of web-pages, i.e., to formulate the PageRank of Google.
For this reason, we call such problem the PaperRank problem, here solved by
using a similar approach to that employed by PageRank. The obtained solution,
which is mathematically grounded, will be used to compare the usual heuristics
of the number of citations with a new one here proposed. Some numerical tests
show that the new heuristics is much more reliable than the currently used
ones, based on the bare number of citations. Moreover, we show that our model
improves on recently proposed ones
Coherence of qubits based on single Ca ions
Two-level ionic systems, where quantum information is encoded in long lived
states (qubits), are discussed extensively for quantum information processing.
We present a collection of measurements which characterize the stability of a
qubit based on the -- transition of single Ca ions
in a linear Paul trap. We find coherence times of 1 ms, discuss the
main technical limitations and outline possible improvements.Comment: Proceedings of "Trapped charged particles and fundamental
interactions" submitted to Journal of Physics B (IoP
Understanding the role of steroids in typical and atypical brain development: Advantages of using a "brain in a dish" approach.
Steroids have an important role in growth, development, sexual differentiation and reproduction. All four classes of steroids, androgens, oestrogens, progestogens and glucocorticoids, have varying effects on the brain. Androgens and oestrogens are involved in the sexual differentiation of the brain, and also influence cognition. Progestogens such as progesterone and its metabolites have been shown to be involved in neuroprotection, although their protective effects are timing-dependent. Glucocorticoids are linked with stress and memory performance, also in a dose- and time-dependent manner. Importantly, dysfunction in steroid function has been implicated in the pathogenesis of disease. Moreover, regulating steroid-signalling has been suggested as potential therapeutic avenue for the treatment of a number of neurodevelopmental, psychiatric and neurodegenerative disorders. Therefore, clarifying the role of steroids in typical and atypical brain function is essential for understanding typical brain functions, as well as determining their potential use for pharmacological intervention in the atypical brain. However, the majority of studies have thus far have been conducted using animal models, with limited work using native human tissue or cells. Here, we review the effect of steroids in the typical and atypical brain, focusing on the cellular, molecular functions of these molecules determined from animal models, and the therapeutic potential as highlighted by human studies. We further discuss the promise of human-induced pluripotent stem cells, including advantages of using three-dimensional neuronal cultures (organoids) in high-throughput screens, in accelerating our understanding of the role of steroids in the typical brain, and also with respect to their therapeutic value in the understanding and treatment of the atypical brain
QCD corrections to the production of at the ILC
A precise calculation of the top quark pair production associated with a hard
photon is essential for testing the electroweak property of the top quark in
the Standard Model (SM). We investigate the one-loop QCD corrections to the
process at the International Linear Collider
(ILC), and find that the -factor can be as large as 1.238 (1.105, 1.060) for
a center-of-mass energy GeV. The transverse momentum
distributions of the top quark and photon are respectively shown at leading
order (LO) and next-to-leading order(NLO). Due to the asymmetric rapidity
distribution of the top (anti-top) quark, we also study the top quark
forward-backward asymmetry () in production at
NLO, which is found to be 45.82 (55.25, 55.89)% for
GeV.Comment: 12 pages, 5 figures, version acceptd by Phys. Lett.
Extracellular Hsp72 concentration relates to a minimum endogenous criteria during acute exercise-heat exposure
Extracellular heat-shock protein 72 (eHsp72) concentration increases during exercise-heat stress when conditions elicit physiological strain. Differences in severity of environmental and exercise stimuli have elicited varied response to stress. The present study aimed to quantify the extent of increased eHsp72 with increased exogenous heat stress, and determine related endogenous markers of strain in an exercise-heat model. Ten males cycled for 90 min at 50% O2peak in three conditions (TEMP, 20°C/63% RH; HOT, 30.2°C/51%RH; VHOT, 40.0°C/37%RH). Plasma was analysed for eHsp72 pre, immediately post and 24-h post each trial utilising a commercially available ELISA. Increased eHsp72 concentration was observed post VHOT trial (+172.4%) (P<0.05), but not TEMP (-1.9%) or HOT (+25.7%) conditions. eHsp72 returned to baseline values within 24hrs in all conditions. Changes were observed in rectal temperature (Trec), rate of Trec increase, area under the curve for Trec of 38.5°C and 39.0°C, duration Trec ≥ 38.5°C and ≥ 39.0°C, and change in muscle temperature, between VHOT, and TEMP and HOT, but not between TEMP and HOT. Each condition also elicited significantly increasing physiological strain, described by sweat rate, heart rate, physiological strain index, rating of perceived exertion and thermal sensation. Stepwise multiple regression reported rate of Trec increase and change in Trec to be predictors of increased eHsp72 concentration. Data suggests eHsp72 concentration increases once systemic temperature and sympathetic activity exceeds a minimum endogenous criteria elicited during VHOT conditions and is likely to be modulated by large, rapid changes in core temperature
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