The significance of the study lies in identifying a scientific and objective indicator that clarifies the extent to which key cognitive and visual abilities contribute to skill performance in tennis. This enables coaches and instructors to design scientifically based educational and training units that incorporate these abilities according to their level of contribution, thereby positively impacting technical performance. The abundance of stimuli in tennis and the difficulty of controlling performance, due to the sport's ongoing developments, require a high level of cognitive and visual abilities. The researchers aimed to examine the problem of inadequate organization in educational content, where one aspect is emphasized over others, and the actual contribution rates of these abilities remain unknown, despite their being fundamental in a sport that demands high levels of concentration, attention, and movement variability. The study aimed to identify the percentage contribution of selected cognitive and visual abilities to the performance of the forehand and backhand strokes in tennis, and to examine the relationship between these abilities and skill performance. The researchers used the descriptive method with a survey and correlational approach. The sample consisted of 30 third-year female students from the College of Physical Education and Sport Sciences for Women at the University of Baghdad. Cognitive and visual tests selected by experts were administered after confirming their validity. The results showed that cognitive and visual abilities play an active role in the performance of the forehand and backhand strokes. Kinesthetic perception, attention, and depth perception made notable contributions, confirming their effectiveness in improving the tennis skill performance of the students. and this achieves one of the sustainable development goals of the United Nations in Iraq which is (Quality Education)
Mass transfer has been studied at rotating cylinder electrodes fabricated with spiral-wound woven-wire meshes using reduction of copper as a test reaction. The experimental data were correlated by an empirical expression between the Sherwood number and the Reynolds number, both regarding the hydraulic diameter as a characteristic length. It was found that the Sherwood number was dependent upon the Reynolds number to the power of 0.521. An enhancement factor was adopted to compare the efficiency of the new rotating cylinder electrode with previous three-dimensional rotating cylinder electrodes. The results showed that the new type has a mass-transfer enhancement factor 2.3 times higher than those obtained with smooth rotating cylinder electr
... Show MoreThis systematic review aimed to investigate the relation between orthodontic treatment (OT) and the incidence of the gingival black triangle (GBT) after completing treatment with a fixed orthodontic appliance, as well as the associated risk factors and the level of alveolar bone. Electronic and hand searches were conducted in three electronic databases for relevant articles published up to March 2022. Retrieved articles went through a two-step screening procedure, and the risk of bias (RoB) was assessed by the Joanna Briggs Institute checklists. The incidence of GBT after OT was set as the primary outcome, while the secondary outcomes were the risk factors associated with GBT and alveolar bone loss following OT. Out of 421 papers, 5
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