1,005 research outputs found

    Tattoos among professional football players in the 2018-2019 Spanish La Liga season

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    Introduction: Data regarding tattoos among football players are limited. We investigated the prevalence and characteristics of tattoos among elite players over a full season in the Spanish La Liga. We assessed whether tattoos had any impact on the performance and behavior of players and teams on the pitch. Materials and methods: Demographic (age, geographic origin, position), performance (goal-scoring) and disciplinary data (yellow/red cards received) for 476 players and overall team statistics over the 2018-2019 season were analyzed according to the presence of visible tattoos (head and neck, upper arms, lower limbs) for each player. Results: Of the 472 players analyzed, 160 (36%) had visible tattoos (upper limbs, 99%; lower limbs, 18.5%; head and neck, 12%), most of which were in black ink (83%). Players from South and Central America had the highest prevalence of visible tattoos (50%) and significantly more head and neck tattoos than Europeans (19% vs. 10% P = 0.02). Tattoos were not significantly related to players' age or position. The mean number of goals scored was higher in the tattooed player group (2.7 +/- 4.6 goals vs. 1.9 +/- 3.3; P = 0.013). There was a correlation between having tattoos and number of goals (Spearman rho 0.103, P = 0.034). Tattooed players were more likely to have received >= 1 yellow card (91% vs. 83.5%, P = 0.03). There was no difference regarding red cards received (15 vs. 14%, P > 0.05). The mean number of yellow cards was higher among players with tattoos than those without (4.4 +/- 3.2 vs. 3.6 +/- 3.2; P = 0.01). However, the proportion of tattooed players in a team did not influence the overall team outcomes. The results were no longer significant when we included only players taking part in at least in 22 matches. Conclusion: Among footballers in La Liga, 36% had visible tattoos, with individual variations attributable to differences in geographic, social, cultural and religious background. Having tattoos was associated with certain aspects of individual performance and discipline. The question whether this factor should be taken into consideration by players' agents and team managers remains open. (c) 2020 Elsevier Masson SAS. All rights reserved.Peer reviewe

    Back-reaction in a cylinder

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    A system is studied in which initially a strong classical electric field exists within an infinitely-long cylinder and no charges are present. Subsequently, within the cylinder, pairs of charged particles tunnel out from the vacuum and the current produced through their acceleration by the field acts back on the field, setting up plasma oscillations. This yields a rough model of phenomena that may occur in the pre-equilibrium formation phase of a quark-gluon plasma. In an infinite volume, this back-reaction has been studied in a field-theory description, and it has been found that the results of a full calculation of this sort are well represented in a much simpler transport formalism. It is the purpose here to explore that comparison for a situation involving a cylindrical volume of given radius.Comment: 19 pages plus 13 figure
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