The Effects of Heading on Neurocognitive Function in Female Collegiate Soccer Players During an Entire Soccer Season

Recently, much debate has occurred regarding the effects of repeated heading by soccer players on their neurocognitive function. PURPOSE: To determine the effects of heading on neurocognitive function in female collegiate soccer players during an entire soccer season. METHODS: Twenty-four members of the 2012 Southwestern University Women’s Soccer team completed the ImPACT test during preseason and postseason, and self-reported the number of headers for the week immediately prior to each testing session. Amount of playing time for each player was determined from records obtained from the Southwestern University Athletics Department. The six composite scores and the cognitive efficiency index from the ImPACT test were measured in each session. Paired t tests were used to evaluate neurocognitive performance at each of the testing periods. Multiple regressions were run to compare the independent variables of playing time and number of headers to the seven ImPACT test composite scores from the preseason and postseason testing periods. RESULTS: There was an increase in visual motor speed, a decrease in reaction time, and an increase in cognitive efficiency from preseason to postseason (t(23) = -4.63, p \u3c 0.001), (t(23) = 2.17, p = 0.041), and (t(23) = -2.45, p = 0.022), respectively. During preseason, number of headers performed significantly predicted reaction time (F(1,22) = 5.37, p = 0.03), and explained approximately 20% of the variance in reaction time (r2 = 0.196). Number of headers performed significantly predicted cognitive efficiency (F(1,22) = 5.56, p = 0.03), and explained approximately 20% of the variance in cognitive efficiency (r2 = 0.202). During postseason, number of minutes played significantly predicted visual memory (F(1,22) = 4.71, p = 0.04), and explained approximately 18% of the variance in visual memory (r2 = 0.176). CONCLUSION: The changes in these neurocognitive variables from preseason to postseason indicated that athletes performed better postseason. The number of headers and the total playing time across one season appear to have had no negative effects on neurocognitive function in these soccer players

An all-optical approach for probing microscopic flows in living embryos

Living systems rely on fluid dynamics from embryonic development to adulthood. To visualize biological fluid flow, devising the proper labeling method compatible with both normal biology and in vivo imaging remains a major experimental challenge. Here, we describe a simple strategy for probing microscopic fluid flows in vivo that meets this challenge. An all-optical procedure combining femtosecond laser ablation, fast confocal microscopy and 3D-particle tracking was devised to label, image and quantify the flow. This approach is illustrated by studying the flow generated within a micrometer scale ciliated vesicle located deep inside the zebrafish embryo and involved in breaking left-right embryonic symmetry. By mapping the velocity field within the vesicle and surrounding a single beating cilium, we show this method can address the dynamics of cilia-driven flows at multiple length scales, and can validate the flow features as predicted from previous simulations. This approach provides new experimental access to questions of microscopic fluid dynamics in vivo

Hard and soft probe - medium interactions in a 3D hydro+micro approach at RHIC

We utilize a 3D hybrid hydro+micro model for a comprehensive and consistent description of soft and hard particle production in ultra-relativistic heavy-ion collisions at RHIC. In the soft sector we focus on the dynamics of (multi-)strange baryons, where a clear strangeness dependence of their collision rates and freeze-out is observed. In the hard sector we study the radiative energy loss of hard partons in a soft medium in the multiple soft scattering approximation. While the nuclear suppression factor $R_{AA}$ does not reflect the high quality of the medium description (except in a reduced systematic uncertainty in extracting the quenching power of the medium), the hydrodynamical model also allows to study different centralities and in particular the angular variation of $R_{AA}$ with respect to the reaction plane, allowing for a controlled variation of the in-medium path-length.Comment: 5 pages, 4 figures, Quark Matter 2006 proceedings, to appear in Journal of Physics

Traditional craftspeople are not copycats: Potter idiosyncrasies in vessel morphogenesis

Ceramics are quintessential indicators of human culture and its evolution across generations of social learners. Cultural transmission and evolution theory frequently emphasizes apprentices' need for accurate imitation (high-fidelity copying) of their mentors' actions. However, the ensuing prediction of standardized fashioning patterns within communities of practice has not been directly addressed in handicraft traditions such as pottery throwing. To fill this gap, we analysed variation in vessel morphogenesis amongst and within traditional potters from culturally different workshops producing for the same market. We demonstrate that, for each vessel type studied, individual potters reliably followed distinctive routes through morphological space towards a much-less-variable common final shape. Our results indicate that mastering the pottery handicraft does not result from accurately reproducing a particular model behaviour specific to the community's cultural tradition. We provide evidence that, at the level of the elementary clay-deforming gestures, individual learning rather than simple imitation is required for the acquisition of a complex motor skill such as throwing pottery

Cilia at the node of mouse embryos sense fluid flow for left-right determination via Pkd2

Unidirectional fluid flow plays an essential role in the breaking of left-right (L-R) symmetry in mouse embryos, but it has remained unclear how the flow is sensed by the embryo. We report that the Ca2+ channel Polycystin-2 (Pkd2) is required specifically in the perinodal crown cells for sensing the nodal flow. Examination of mutant forms of Pkd2 shows that the ciliary localization of Pkd2 is essential for correct L-R patterning. Whereas Kif3a mutant embryos, which lack all cilia, failed to respond to an artificial flow, restoration of primary cilia in crown cells rescued the response to the flow. Our results thus suggest that nodal flow is sensed in a manner dependent on Pkd2 by the cilia of crown cells located at the edge of the node.CREST of the Japan Science and Technology Corporation; NIH [P30 DK090744]; Human Frontier Science Program [ST00246/2003C]; Deutsche Forschungsgemeinschaft [PE 853/2]; Japan Society for the Promotion of Science; American Heart Association [R10682]info:eu-repo/semantics/publishedVersio

Space-time evolution of bulk QCD matter

We introduce a combined fully three-dimensional macroscopic/microscopic transport approach employing relativistic 3D-hydrodynamics for the early, dense, deconfined stage of the reaction and a microscopic non-equilibrium model for the later hadronic stage where the equilibrium assumptions are not valid anymore. Within this approach we study the dynamics of hot, bulk QCD matter, which is being created in ultra-relativistic heavy ion collisions at RHIC. Our approach is capable of self-consistently calculating the freezeout of the hadronic system, while accounting for the collective flow on the hadronization hypersurface generated by the QGP expansion. In particular, we perform a detailed analysis of the reaction dynamics, hadronic freezeout, and transverse flow.Comment: 24 pages, 27 figure