1,365 research outputs found

    EFFECT OF FATIGUE ON BASKETBALL THREE POINTS SHOT KINEMATICS

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    The purpose of this study was to measure the effect of fatigue on basketball shooting kinematics. Young elite players (n=8) were included in the study. Maximal and minimal 3D joint angles, at maximum and minimum centre of mass height were measured with inertial sensors (Moven Biomech, Xsens). Each player performed four 3 points shot (3PS) in dynamic conditions before and after a submaximal exercise (70% of maximal exhausting). This exercise consisted in a repetition of 20-meters sprints with 5 jumps between each sprint. Results showed that fatigue decreased hip joint angle and increased shoulder joint angle when the center of mass was at its lowest point. These biomechanical modifications did not alter the precision of shooting. This study demonstrated that fatigue has small effect on kinematics and precision of the 3PS

    The effects of repeated sprints on the kinematics of 3-point shooting in basketball

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    Fatigue modifies the kinematics of various sports-related movements. Basketball induces fatigue, however, the effects of fatigue on the kinematics of shooting have never been studied. This study analysed the effects of fatigue induced by repeated sprints on the kinematics of 3-point shooting (3PS) in young, elite basketball players (U18 level). 3D joint angles were calculated at the maximum and minimum heights of the centre of mass during 3PS, using inertial measurement units (Biomech system, Xsens Technologies BV, Enschede, The Netherlands). Height, velocity and the angle of the ball at the time of release were extrapolated from the wrist joint angles. All players performed four 3PS actions in dynamic conditions before and after a fatigue protocol at 70% of their maximal exercise capacity. The fatigue protocol consisted of a shuttle test with repeated 20-m sprints interspersed with sets of 5 jumps. There was no change in the kinematics of 3PS (p > 0.05), or the ball release variables (p > 0.05) following the fatigue protocol. This suggests that elite basketball players are able to cope with physical fatigue while performing coordinated movements such as 3PS

    фольклорно-етнографічні матеріали на сторінках журналу «Основа»

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    In the article folk and ethnographical materials of the «Osnova» magazine are analyzed. The role of this edition in development of the ethnography is defined

    Comparative evaluation of gene-set analysis methods

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    <p>Abstract</p> <p>Background</p> <p>Multiple data-analytic methods have been proposed for evaluating gene-expression levels in specific biological pathways, assessing differential expression associated with a binary phenotype. Following Goeman and Bühlmann's recent review, we compared statistical performance of three methods, namely Global Test, ANCOVA Global Test, and SAM-GS, that test "self-contained null hypotheses" Via. subject sampling. The three methods were compared based on a simulation experiment and analyses of three real-world microarray datasets.</p> <p>Results</p> <p>In the simulation experiment, we found that the use of the asymptotic distribution in the two Global Tests leads to a statistical test with an incorrect size. Specifically, p-values calculated by the scaled <it>χ</it><sup>2 </sup>distribution of Global Test and the asymptotic distribution of ANCOVA Global Test are too liberal, while the asymptotic distribution with a quadratic form of the Global Test results in p-values that are too conservative. The two Global Tests with permutation-based inference, however, gave a correct size. While the three methods showed similar power using permutation inference after a proper standardization of gene expression data, SAM-GS showed slightly higher power than the Global Tests. In the analysis of a real-world microarray dataset, the two Global Tests gave markedly different results, compared to SAM-GS, in identifying pathways whose gene expressions are associated with <it>p53 </it>mutation in cancer cell lines. A proper standardization of gene expression variances is necessary for the two Global Tests in order to produce biologically sensible results. After the standardization, the three methods gave very similar biologically-sensible results, with slightly higher statistical significance given by SAM-GS. The three methods gave similar patterns of results in the analysis of the other two microarray datasets.</p> <p>Conclusion</p> <p>An appropriate standardization makes the performance of all three methods similar, given the use of permutation-based inference. SAM-GS tends to have slightly higher power in the lower <it>α</it>-level region (i.e. gene sets that are of the greatest interest). Global Test and ANCOVA Global Test have the important advantage of being able to analyze continuous and survival phenotypes and to adjust for covariates. A free Microsoft Excel Add-In to perform SAM-GS is available from <url>http://www.ualberta.ca/~yyasui/homepage.html</url>.</p

    Silicon Photo-Multiplier radiation hardness tests with a beam controlled neutron source

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    We report radiation hardness tests performed at the Frascati Neutron Generator on silicon Photo-Multipliers, semiconductor photon detectors built from a square matrix of avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to 7x10^10 1-MeV-equivalent neutrons per cm^2. Detector performances have been recorded during the neutron irradiation and a gradual deterioration of their properties was found to happen already after an integrated fluence of the order of 10^8 1-MeV-equivalent neutrons per cm^2.Comment: 7 pages, 6 figures, Submitted to Nucl. Inst. Meth.

    Effects of genotype and environmental conditions on grapevine (Vitis vinifera L.) shoot morphology

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    Grapevine shoot morphology is widely studied for both ampelography and growing adaptation to environmental stresses. However, few is known concerning the relative contribution and interactions of the genotype and of the growing conditions to the vegetative growth. In this work, seven grapevine cultivars were studied in three geographically distant ampelographic collections to maximize the genotype and environment differences among samples. Phytomers were studied concerning the leaf area and the stem and petiole diameters and lengths. These measurements allowed the calculation of derivative parameters to describe the proportions among elements. Despite most of the studied parameters significantly discriminated both factors (cultivar and growing conditions), it was possible to identify, for each one of them, the most promising parameters based on their relative variance explanation. In fact, a negative correlation was observed between the roles of genotype and environment among the studied parameters. The low interaction effect suggested a stability in the plant behaviors, confirming the possibility to use vegetative descriptions for both cultivar discrimination and growing conditions. Future studies will be performed to develop specific indexes based on the phenotypical variability of shoot morphology described here
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