Effects of a school-based karate intervention on academic achievement, psychosocial functioning, and physical fitness: A multi-country cluster randomized controlled trial.

Purpose: To examine the effects of a school-based karate intervention on academic achievement, psychosocial functioning, and physical fitness in children aged 7-8 years.

Methods: Twenty schools in 5 different European countries (2 second-grade classrooms per school) participated in a cluster randomized controlled trial (Sport at School trial). Participants were assigned to either a control group, which continued with their habitual physical education lessons, or to an intervention group, which replaced these lessons with a 1-year karate intervention (Karate Mind and Movement program).

Effects of a school-based karate intervention on academic achievement, psychosocial functioning, and physical fitness: A multi-country cluster randomized controlled trial.

Purpose: To examine the effects of a school-based karate intervention on academic achievement, psychosocial functioning, and physical fitness in children aged 7-8 years.

Methods: Twenty schools in 5 different European countries (2 second-grade classrooms per school) participated in a cluster randomized controlled trial (Sport at School trial). Participants were assigned to either a control group, which continued with their habitual physical education lessons, or to an intervention group, which replaced these lessons with a 1-year karate intervention (Karate Mind and Movement program).

Backward optical parametric efficiency in quasi-phase-matched GaN waveguide presenting stitching faults.

We model a backward mirrorless optical parametric oscillator in a fragmented GaN waveguide consisting of a sequence of submicronic periodically poled elements separated by uniformly polarized connection sections representing stitching errors. We find that the generated coherent phase of the backscattered wave locks the phases of the forward propagating waves in such a way that the dynamics is nonintuitivelly as efficient as for a uniform quasi-phase-matched waveguide. The best coherence transfer to the backward wave, obtained for perfect group-velocity matching of the forward propagating waves, requires a nanoscale poled periodicity, which is achieved in GaN through epitaxy.

Experimental phase-space-based optical amplification of scar modes.

Wave billiards which are chaotic in the geometrical limit are known to support nongeneric spatially localized modes called scar modes. The interaction of the scar modes with gain has been recently investigated in optics in microcavity lasers and vertical-cavity surface-emitting lasers. Exploiting the localization properties of scar modes in their wave-analogous phase-space representation, we report experimental results of scar mode selection by gain in a doped D-shaped optical fiber.

Unexpected light behaviour in periodic segmented waveguides.

In this article, it is shown that multimode periodic segmented waveguides (PSW) are versatile optical systems in which properties of wave chaos can be highlighted. Numerical wave analysis reveals that structures of quantum phase space of PSW are similar to Poincaré sections which display a mixed phase space where stability islands are surrounded by a chaotic sea. Then, unexpected light behavior can occur such as, input gaussian beams do not diverge during the propagation in a highly multimode waveguide.