Detection of Cross-Correlation between Gravitational Lensing and γ Rays

In recent years, many γ-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe has been shown to be a promising tool. We report here the first identification of a cross-correlation signal between γ rays and the distribution of mass in the Universe probed by weak gravitational lensing. We use data from the Dark Energy Survey Y1 weak lensing data and the Fermi Large Area Telescope 9-yr γ-ray data, obtaining a signal-to-noise ratio of 5.3. The signal is mostly localized at small angular scales and high γ-ray energies, with a hint of correlation at extended separation. Blazar emission is likely the origin of the small-scale effect. We investigate implications of the large-scale component in terms of astrophysical sources and particle dark matter emission

Detection of cross-correlation between gravitational lensing and gamma rays

International audienceIn recent years, many γ-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe has been shown to be a promising tool. We report here the first identification of a cross-correlation signal between γ rays and the distribution of mass in the Universe probed by weak gravitational lensing. We use data from the Dark Energy Survey Y1 weak lensing data and the Fermi Large Area Telescope 9-yr γ-ray data, obtaining a signal-to-noise ratio of 5.3. The signal is mostly localized at small angular scales and high γ-ray energies, with a hint of correlation at extended separation. Blazar emission is likely the origin of the small-scale effect. We investigate implications of the large-scale component in terms of astrophysical sources and particle dark matter emission

Repeated sprint ability on synthetic turf vs. natural grass in young soccer players

Introduction Synthetic pitches are greatly increasing in popularity, but little is known on how playing on artificial turf rather than natural grass influences the physical performance in soccer. The aim of this study is to compare the two surfaces about the outcomes of a repeated sprint ability (RSA) test, shown as a valid indicator of match-related physical performance in soccer players2. We hypothesize that players that usually train on synthetic turf would perform better on that surface compared to natural grass. Methods Eighteen young male soccer players from two teams were recruited. Team A (n=11; 16.6  0.3 ys; 71.9  7.4 Kg; 178.5  4.8 cm) usually trains on a synthetic pitch, while Team B (n=7; 18.7  0.7 ys; 71.7  6.7 Kg; 178.3  5.7 cm) usually trains on natural grass. All the players performed two identical RSA tests, respectively on synthetic (Synt) turf (Football Green 57 SL, Limonta Sport, Italy) and natural grass (Nat). The protocol consisted of 6x40 m shuttle run sprints at maximal speed with 20 s of passive recovery1. In each sprint, the players started from a line, reached another line 20 m apart, touched it with a foot, and came back. Best time of a single trial (TBEST), mean time of the 6 sprints (TMEAN) and percent decrement (Decr%) = ([TMEAN/TBEST]x100)\u2013100)) were assessed. Paired Wilcoxon tests were used to compare mean values between Nat and Synt. Significance was set at p<0.01. Results The team that generally trains on synthetic turf showed significantly lower TBEST and TMEAN on Synt compared to Nat, while Decr% was unchanged. No significant differences were found for the players usually training on natural grass. Discussion \u2013 Conclusions The results supported our hypothesis that those players who are familiar with artificial turf perform better in the considered RSA test on synthetic than on natural grass. The lower TBEST and TMEAN observed in players of Team A on the artificial surface may be due to their ability to reduce the braking time before the inversion of direction by exploiting the higher adherence of the synthetic turf. Therefore, training habitually on artificial turf may advantageously influence the physical performance in soccer matches taking place on synthetic fields

Comparison of physiological responses to an incremental running test on treadmill, natural grass, and synthetic turf in young soccer players

This study aimed to compare the physiological responses to a running test often used to assess lactate thresholds in soccer players when performed with an identical protocol on treadmill (Tr), natural grass (Nat), and synthetic turf (Synt). Eighteen young soccer players (mean +/- SD: age, 17.4 +/- 0.8 years; body mass, 66.2 +/- 6.7 kg; height, 175.8 +/- 5.7 cm) performed on each surface a multistage running test, including 4-minutes stages separated by a 1-minute rest, with initial speed set at 8 kmxh and increased of 2 km.h after each stage. Blood lactate concentration (La) and heart rate (HR) were assessed. The test ended when La exceeded 4 mmolxL. At each of the stages completed in the three conditions by all the subjects (8, 10, 12, and 14 kmxh), La was higher in Synt vs. both Nat and Tr with differences of at least 0.6 mmolxL (p < 0.05), whereas HR was higher (p < 0.05) in Synt vs. Nat with differences from 4.3 bxmin (at 10 kmxh) to 6.4 bxmin (at 8 kmxh). Running speed at the 4 mmolxL La threshold was lower (p < 0.05) in Synt (13.1 +/- 1.1 kmxh) than in Nat (13.9 +/- 1.2 kmxh) and Tr (14.4 +/- 1.3 kmxh). The La/HR curve obtained in Synt was shifted upward compared with the Nat and Tr curves, indicating higher La values at given HRs. These results could be mostly explained by adaptations of running mechanical patterns to surface properties that affect the energy requirements of running. This study emphasized the importance of testing soccer players on the specific surface used for training activities when assessing lactate threshold indices to prescribe and monitor field trainin