289 research outputs found
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school girlsâ basketball (2005â2006 through 2013â2014) and National Collegiate Athletic Association womenâs basketball (2004â2005 through 2013â2014)
Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of girlsâ and womenâs basketball injury data. Objective: To describe the epidemiology of injuries sustained in high school girlsâ basketball in the 2005â2006 through 2013â2014 academic years and collegiate womenâs basketball in the 2004â2005 through 2013â2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from basketball teams in high school girls (annual average ÂŒ 100) and collegiate women (annual average ÂŒ 57). Patients or Other Participants: Girlsâ and womenâs basketball players who participated in practices and competitions during the 2005â2006 through 2013â2014 academic years in high school or the 2004â2005 through 2013â2014 academic years in college. Main Outcome Measure(s): Certified athletic trainers collected time-loss (24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs) were calculated. Injury rate ratios (IRRs) with 95% confidence intervals (CIs) were used to compare injury rates by school size or division, time in season, event type, and competition level. Results: The High School Reporting Information Online system documented 2930 time-loss injuries during 1 609 733 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 3887 time-loss injuries during 783 600 AEs. The injury rate was higher in college than in high school (4.96 versus 1.82/1000 AEs; IRR ÂŒ 2.73; 95% CI ÂŒ 2.60, 2.86). The injury rate was higher in competitions than in practices for both high school (IRR ÂŒ 3.03; 95% CI ÂŒ 2.82, 3.26) and collegiate (IRR ÂŒ 1.99; 95% CI ÂŒ 1.86, 2.12) players. The most common injuries at both levels were ligament sprains, concussions, and muscle/tendon strains; the majority of injuries affected the ankle, knee, and head/face. These injuries were often caused by contact with another player or a noncontact mechanism. Conclusions: Injury rates were higher in collegiate than in high school athletes and in competitions than in practices. Similarities in distributions of injuries by body parts, specific diagnoses, and mechanisms of injury suggest that both levels may benefit from similar injury-prevention strategies
The first decade of web-based sports injury surveillance: Descriptive epidemiology of injuries in US high school boysâ basketball (2005â2006 through 2013â2014) and National Collegiate Athletic Association menâs basketball (2004â2005 through 2013â2014)
Context: The advent of Web-based sports injury surveillance via programs such as the High School Reporting Information Online system and the National Collegiate Athletic Association Injury Surveillance Program has aided the acquisition of boysâ and menâs basketball injury data. Objective: To describe the epidemiology of injuries sustained in high school boysâ basketball in the 2005â2006 through 2013â2014 academic years and collegiate menâs basketball in the 2004â2005 through 2013â2014 academic years using Web-based sports injury surveillance. Design: Descriptive epidemiology study. Setting: Online injury surveillance from basketball teams of high school boys (annual average ÂŒ 100) and collegiate men (annual average ÂŒ 55). Patients or Other Participants: Boysâ and menâs basketball players who participated in practices and competitions during the 2005â2006 through 2013â2014 academic years in high school or the 2004â2005 through 2013â2014 academic years in college. Main Outcome Measures: Athletic trainers collected time-loss (24 hours) injury and exposure data. Injury rates per 1000 athlete-exposures (AEs) were calculated. Injury rate ratios (IRRs) with 95% confidence intervals (CIs) compared injury rates by school size or division, time in season, event type, and competition level. Results: The High School Reporting Information Online system documented 3056 time-loss injuries during 1 977 480 AEs; the National Collegiate Athletic Association Injury Surveillance Program documented 4607 time-loss injuries during 868 631 AEs. The injury rate was higher for college than for high school (5.30 versus 1.55/1000 AE; IRR ÂŒ 3.43; 95% CI ÂŒ 3.28, 3.59). The injury rate was higher for competitions than for practices in both high school (IRR ÂŒ 2.38; 95% CI ÂŒ 2.22, 2.56) and college (IRR ÂŒ 2.02; 95% CI ÂŒ 1.90, 2.14). The most common injuries at both levels were ligament sprains, muscle/ tendon strains, and concussions; most injuries affected the ankle, knee, and head/face. Injuries were most often caused by contact with another player or noncontact mechanisms. Conclusions: Injury rates were greater among collegiate players compared with high school players and were greater during competitions than practices at both levels. Distributions of injuries by body part, diagnoses, and mechanisms of injury were similar, suggesting that athletes at both levels may benefit from similar injury-prevention strategies
High-contrast imaging constraints on gas giant planet formation - The Herbig Ae/Be star opportunity
Planet formation studies are often focused on solar-type stars, implicitly
considering our Sun as reference point. This approach overlooks, however, that
Herbig Ae/Be stars are in some sense much better targets to study planet
formation processes empirically, with their disks generally being larger,
brighter and simply easier to observe across a large wavelength range. In
addition, massive gas giant planets have been found on wide orbits around early
type stars, triggering the question if these objects did indeed form there and,
if so, by what process. In the following I briefly review what we currently
know about the occurrence rate of planets around intermediate mass stars,
before discussing recent results from Herbig Ae/Be stars in the context of
planet formation. The main emphasis is put on spatially resolved polarized
light images of potentially planet forming disks and how these images - in
combination with other data - can be used to empirically constrain (parts of)
the planet formation process. Of particular interest are two objects, HD100546
and HD169142, where, in addition to intriguing morphological structures in the
disks, direct observational evidence for (very) young planets has been
reported. I conclude with an outlook, what further progress we can expect in
the very near future with the next generation of high-contrast imagers at 8-m
class telescopes and their synergies with ALMA.Comment: Accepted by Astrophysics and Space Science as invited short review in
special issue about Herbig Ae/Be stars; 12 pages incl. 5 figures, 2 tables
and reference
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Model-independent search for CP violation in D0âKâK+ÏâÏ+ and D0âÏâÏ+Ï+Ïâ decays
A search for CP violation in the phase-space structures of D0 and View the MathML source decays to the final states KâK+ÏâÏ+ and ÏâÏ+Ï+Ïâ is presented. The search is carried out with a data set corresponding to an integrated luminosity of 1.0 fbâ1 collected in 2011 by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. For the KâK+ÏâÏ+ final state, the four-body phase space is divided into 32 bins, each bin with approximately 1800 decays. The p-value under the hypothesis of no CP violation is 9.1%, and in no bin is a CP asymmetry greater than 6.5% observed. The phase space of the ÏâÏ+Ï+Ïâ final state is partitioned into 128 bins, each bin with approximately 2500 decays. The p-value under the hypothesis of no CP violation is 41%, and in no bin is a CP asymmetry greater than 5.5% observed. All results are consistent with the hypothesis of no CP violation at the current sensitivity
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
Search for the lepton-flavor-violating decays Bs0âe±Όâ and B0âe±Όâ
A search for the lepton-flavor-violating decays Bs0âe±Όâ and B0âe±Όâ is performed with a data sample, corresponding to an integrated luminosity of 1.0ââfb-1 of pp collisions at âs=7ââTeV, collected by the LHCb experiment. The observed number of Bs0âe±Όâ and B0âe±Όâ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B(Bs0âe±Όâ)101ââTeV/c2 and MLQ(B0âe±Όâ)>126ââTeV/c2 at 95% C.L., and are a factor of 2 higher than the previous bounds
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam
experiments at storage rings. These measurements are necessary to determine the
absolute cross-sections of reaction processes and are valuable to quantify the
performance of the accelerator. Using data taken in 2010, LHCb has applied two
methods to determine the absolute scale of its luminosity measurements for
proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In
addition to the classic "van der Meer scan" method a novel technique has been
developed which makes use of direct imaging of the individual beams using
beam-gas and beam-beam interactions. This beam imaging method is made possible
by the high resolution of the LHCb vertex detector and the close proximity of
the detector to the beams, and allows beam parameters such as positions, angles
and widths to be determined. The results of the two methods have comparable
precision and are in good agreement. Combining the two methods, an overall
precision of 3.5% in the absolute luminosity determination is reached. The
techniques used to transport the absolute luminosity calibration to the full
2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6,
9 and 10 and corresponding explanation in the tex
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) and the direct CP asymmetry in B0 -> K*0 gamma
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 phi gamma has been measured using an integrated luminosity of 1.0 fb-1
of pp collision data collected by the LHCb experiment at a centre-of-mass
energy of sqrt(s)=7 TeV. The value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 ->
phi gamma) = 1.23 +/- 0.06(stat.) +/- 0.04(syst.) +/- 0.10(fs/fd), where the
first uncertainty is statistical, the second is the experimental systematic
uncertainty and the third is associated with the ratio of fragmentation
fractions fs/fd. Using the world average value for BR(B0 -> K*0 gamma), the
branching fraction BR(Bs0 -> phi gamma) is measured to be (3.5 +/- 0.4) x
10^{-5}.
The direct CP asymmetry in B0 -> K*0 gamma decays has also been measured with
the same data and found to be A(CP)(B0 -> K*0 gamma) = (0.8 +/- 1.7(stat.) +/-
0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the
previous experimental results and theoretical expectations.Comment: 21 pages, 3 figues, 4 table
Absolute luminosity measurements with the LHCb detector at the LHC
Absolute luminosity measurements are of general interest for colliding-beam
experiments at storage rings. These measurements are necessary to determine the
absolute cross-sections of reaction processes and are valuable to quantify the
performance of the accelerator. Using data taken in 2010, LHCb has applied two
methods to determine the absolute scale of its luminosity measurements for
proton-proton collisions at the LHC with a centre-of-mass energy of 7 TeV. In
addition to the classic "van der Meer scan" method a novel technique has been
developed which makes use of direct imaging of the individual beams using
beam-gas and beam-beam interactions. This beam imaging method is made possible
by the high resolution of the LHCb vertex detector and the close proximity of
the detector to the beams, and allows beam parameters such as positions, angles
and widths to be determined. The results of the two methods have comparable
precision and are in good agreement. Combining the two methods, an overall
precision of 3.5% in the absolute luminosity determination is reached. The
techniques used to transport the absolute luminosity calibration to the full
2010 data-taking period are presented.Comment: 48 pages, 19 figures. Results unchanged, improved clarity of Table 6,
9 and 10 and corresponding explanation in the tex
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