mohammad behdani

 The application of principles of motor learning in children with deficit/hyperactivity disorder (ADHD) is essential. This study investigated the effect of constant and variable practice on learning soccer pass skills in children with attention deficit hyperactivity disorder and normal children.

 For this purpose, two groups of 34 ADHD and 34 typically developing children with a mean age of (8.36±0.51) were selected by purposive sampling. Each group was randomly divided into experimental (variable practice) and control (constant practice) subgroups. At first, the Pretest of the soccer pass was performed based on the Mor-Christian General Soccer Ability Skill Test Battery. Then the training program was conducted for 8 weeks consisting of two sessions per week (20 trials per session) for 45 minutes. After the last session, Post-test, and after one week, the retention and transfer tests were performed on two consecutive days. Data were analyzed using mixed-design ANOVA and one-way ANOVA. 

The results showed a significant within-group difference in all training groups from Pretest to Post-test (P=0.001). Comparison of Post-test, retention, and transfer tests in the training groups showed no significant difference between the training groups, but comparing the means indicates that in both groups of typically developing children and children with ADHD, variable training resulted in better retention and transfer than constant training.

In general, the results of this study showed that in children with ADHD, as in typically developing children, variable practice is probably more effective in the learning of soccer pass skills than constant practice.

One-dimensional TiO2/SiO2 core-shell nanofibers were fabricated using a single-nozzle co-electrospinning process with phase-separated, mixed polymer composite solution. The core and shell are composed of Polyvinylpyrrolidone (PVP) and Polyacrylonitrile (PAN) polymers with uniform distribution of TiO2 and SiO2 nanoparticles (NPs), respectively. The NPs were synthesized via sol-gel reaction, simultaneously, in the respective polymer solutions. The morphologies and structures of the fabricated TiO2/SiO2 core-shell nanofibers were investigated by XRD, FTIR, SEM, EDS and TEM images. The influence of different amounts of TiO2 and SiO2 precursors on the photocatalytic and UV-shielding performance of TiO2/SiO2 core-shell nanofibers were studied. Photocatalytic activity of the nanofibers evaluated by observing photodegradation of Methyl Orange (MO) aqueous solution under irradiation of ultraviolet (UV) light. Our results on the TiO2/SiO2 core-shell nanofibers indicate good potential for superior applications in photocatalytic and UV shielding devices.