Search

At 8:40 p.m. (Beijing time) on July 23, 2019, a large landslide occurred at Jichang, a village in Shuicheng, Guizhou Province, China, resulting in 42 deaths, 9 missing people, and 21 buildings buried. Field investigation and unmanned aerial vehicle (UAV) photography allow us to characterize this slope failure and analyze its process and causes. Initially, the materials detached from the mountainside and slid over from the slope. Then, the sliding materials partly accumulated in the middle and upper parts of the slope which were blocked by a convex terrain. The rest turned into a high-speed debris flow, divided by the stable block, and descended along two existing gullies at high velocity, and finally decelerating and accumulating. Based on the high-resolution post-sliding DEM data, the original topography of the study area was reconstructed to estimate the volume of the landslide that was about 1,500,000 m3. Based on a first-order evaluation of the landslide kinematics, the whole sliding process of this event lasted about 60 s, the maximum speed was about 25 m/s, and the average speed was 16.6 m/s, indicating a typical high-speed long-runout debris flow. Analysis suggests that continuous heavy rainfall was the dominant factor to trigger this landslide, and the loose weathered regolith and special local topography were the basic intrinsic factors for this event. [ABSTRACT FROM AUTHOR]

Background: Swimming was investigated according to swimmer's body build, technique of movement of free swimming, i.e. position of body parts, stroke length, rate, velocity, and indices, technique of start and turn, improving of propulsion, diminishing of resistance forces, structure of the entire distance divided into the start segment, free swimming, turn segments, the finish segment. Unfortunately there is lack of research on tactics of swimming taking into account the entire distance. The aim of this study was to obtain a knowledge on tactics of long distance swimming at the high professional level in order to qualify to the Olympic team. Materials and methods: Eight men - finalists of 1500 m distance of free style swimming were investigated. They participated in the 2008 U.S. Olympic Team Trials in order to go for the Beijing 2008 Olympic Games. Data on the entire time of swimming and also split times for every 50 m were obtained from the server of the OMEGA watch maker. The distribution of velocity of swimming for the entire distance was presented. Results: It was revealed that the winner, and also swimmers who broke the world and American records (separate data) had their distribution of swimming as ascending line and with very small difference between segmental velocities and that of the entire distance. Other swimmers had descending line or flat line (the last two at the final who had the slowest velocities) of their distribution of swimming. Conclusions: In order to approach sport performance with proper tactics sportspersons need to be taught how to achieve good distribution of velocity of movement along the entire distance of swimming. [ABSTRACT FROM AUTHOR]