OBJECTIVES The perceptual ability to detect movement is essential for expert table tennis players. A spatiotemporal occlusion paradigm was employed to examine the critical information that facilitates athletes’ perception.METHODS Thirty-one expert table tennis players, 29 participants and 2 demonstrators, volunteered to participate in the study. Four types of temporal conditions and five types of spatial occlusions were displayed in experimental videos of two opponents playing a table tennis forehand stroke. Period t1–4 represented the four temporal conditions, with 250, 500, 750, and 1000 ms of action being occluded, respectively. The five types of spatial occlusion involved showing the kinematics of only the ball, paddle, arm, trunk, or head. The participants were instructed to judge the landing direction of the ball on the basis of the information in the footage.RESULTS The footage depicted the longest period of play. Furthermore, in separate trials, the spatial information (for the ball, torso, or head) was missing because of occlusion. The absence of such critical spatiotemporal information impaired the ability of players to make an accurate prediction.CONCLUSION Players obtained crucial spatiotemporal information if the timeframe of the video was relatively complete and spatial information on the opponent’s torso and head was available. For peak performance, expert table tennis players perceive and detect the optical flow of the ball’s flight and consider invariant information concerning their opponent’s torso and head.
The relationship between environmental regulation and green economic growth has become a focal issue in China. This study utilizes the environmental information disclosure (EID) policy as a quasi-natural experiment in the Chinese context. Using a sample of 280 Chinese cities from 2003–2019 and measuring urban green total factor productivity (GTFP), the propensity score matching and difference-in-difference methods are applied to assess the impact mechanism of EID on urban GTFP in China. The results show that, first, the urban GTFP showed a decreasing trend from 2003 to 2008 and a general increasing trend from 2009 to 2019. The EID policy had a significantly positive impact on GTFP, and this finding remained robust after a series of tests. Second, the policy effect of EID was more pronounced in large and medium-sized cities than in small cities and eastern and central regions. The mechanism analysis shows that a positive effect from EID on GTFP in cities can be achieved through green technological innovation and industrial agglomeration.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.