78 research outputs found

    IDENTIFICATION OF FLOOR AND VAULTING APTITUDE IN 8·14 YEAR OLD TALENT-SELECTED FEMALE GYMNASTS

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    Training programs can be designed and monitored to maximise high aptitude for floor and vault when the key attributes are identified, and then used to recognize apparatus ability in talent-selected gymnasts. The aim of this study was to identify the anthropometric and physical prerequisites for high difficulty floor tumbling and vaulting. Twenty female gymnasts performed handstand push-offs, single and multiple jumps on a portable Kistler force plate. The gymnasts were also examined when sprinting, vaulting, and performing broad jumps. Each gymnast's best vault, three best noor tumbling skills and their anthropometric characteristics were also recorded. High squat jump force and power, vault take-off velocity, and sprinting speed indicated vaulting talent. High vault running speed and reduced handstand push-off ground contact time indicated high floor ability

    NOVEL INSIGHTS ON LOWER LIMB MUSCULOSKELETAL HEALTH AND PERFORMANCE IN PRE-ADOLESCENT AND ADOLESCENT GYMNASTS

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    New analyses are presented from the data of Bradshaw and Le Rossignol (2004) to examine the relationship between musculoskeletal health, and physical and performance qualities, with measures of leg stiffness in a group of female gymnasts. A gymnasts leg stiffness can be assessed through continuous jump (straight & bent legged) series tests, as well as from rebound jumps. Although the observations are retrospective, the study revealed a potential safe zone for ankle extensor stiffness. The gymnast with low stiffness had previously suffered a landing ankle injury; whilst four gymnasts with high stiffness had histories of take-off ankle injuries. Aside from profiling physical performance qualities, biomechanical (kinetic) testing has the potential to also aid in the assessment and management of the athlete’s functional musculoskeletal health (rehabilitation, injury risk)

    Search for CP Violation in the Decay Z -> b (b bar) g

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    About three million hadronic decays of the Z collected by ALEPH in the years 1991-1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z -> b \bar{b} g. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, h^b=h^AbgVbh^VbgAb{\hat{h}}_b = {\hat{h}}_{Ab}g_{Vb}-{\hat{h}}_{Vb}g_{Ab} and hb=h^Vb2+h^Ab2h^{\ast}_b = \sqrt{\hat{h}_{Vb}^{2}+\hat{h}_{Ab}^{2}}, limits of \hat{h}_b < 0.59and and h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st

    Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs

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    Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population

    First measurement of the quark-to-photon fragmentation function

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    Improved tau polarisation measurement

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    Production of excited beauty states in Z decays

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    A data sample of about 3.0 million hadronic Z decays collected by the ALEPH experiment at LEP in the years 1991 through 1994, is used to make an inclusive selection of B~hadron events. In this event sample 4227 \pm 140 \pm 252 B^* mesons in the decay B^* \to B \gamma and 1944 \pm 108 \pm 161 B^{**} mesons decaying into a B~meson and a charged pion are reconstructed. For the well established B^* meson the following quantities areobtained: \Delta M = M_{B^*} - M_{B} = (45.30\pm 0.35\pm 0.87)~\mathrm{MeV}/c^2 and N_{B^*}/(N_B+N_{B^*}) = (77.1 \pm 2.6 \pm 7.0)\%. The angular distribution of the photons in the B^* rest frame is used to measure the relative contribution of longitudinal B^* polarization states to be \sigma_L/(\sigma_L + \sigma_T)= (33 \pm 6 \pm 5)\%. \\ Resonance structure in the M(B\pi)-M(B) mass difference is observed at (424 \pm 4 \pm 10)~\mathrm{MeV}/c^2. Its shape and position is in agreement with the expectation for B^{**}_{u,d} states decaying into B_{u,d}^{(*)} \pi^\pm. The signal is therefore interpreted as arising from them. The relative production rate is determined to be \frac{BR(Z \to b \to B_{u,d}^{**})}{BR(Z \to b \to B_{u,d})} = [27.9 \pm 1.6(stat) \pm 5.9(syst) \phantom{a}^{+3.9}_{-5.6}(model)]\%. where the third error reflects the uncertainty due to different production and decay models for the broad B_{u,d}^{**} states

    Inclusive production of neutral vector mesons in hadronic Z decays

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    Tau hadronic branching ratios

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    From 64492 selected \tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \tau-\mu universality in hadronic decays, g_\tau/g_\mu \ = \ 1.0013 \ \pm \ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \tau decay width: R_{\tau ,V} \ = \ 1.788 \ \pm \ 0.025 and R_{\tau ,A} \ = \ 1.694 \ \pm \ 0.027. The ratio (R_{\tau ,V} - R_{\tau ,A}) / (R_{\tau ,V} + R_{\tau ,A}), equal to (2.7 \pm 1.3) \ \%, is a measure of the importance of QCD non-perturbative contributions to the hadronic \tau decay widt

    Production of orbitally excited charm mesons in semileptonic B decays

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