171 research outputs found
METHOD TO VISUALIZE AND ANALYZE SIMILARITIES OF MOVEMENTS – USING THE EXAMPLE OF KARATE KICKS
Most sports movements are very complex. In order to estimate similarities between the movements many biomechanical parameters are necessary. This impairs the clearness of the classification of similar movements. Another variant is the use of nonlinear procedures which allow the consideration of the movement on the whole. But a connection to the single biomechanical parameters is not given. The aim of this paper is to introduce a procedure to visualize the movement coordination to get a visual impression of the whole movement, and in addition further analyses by means of statistical tools to confirm similarities and variabilities between the movements were presented using the example of Mae-Geri
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Heavy ion injector for the CERN Linac 1
An injector system has been designed to provide a fully stripped oxygen beam for acceleration in the CERN PS complex. An ECR source will provide an O/sup 6/+ beam to a heavy ion RFQ accelerator. The beam from the RFQ will be further accelerated by the CERN Linac 1 (Old Linac) in the 2 ..beta.. lambda-mode to an energy of 12.5 MeV/u at which point it will be fully stripped for subsequent acceleration in the CERN synchrotrons. The specifications of the new equipment and modifications to the existing linear accelerator are described
The total synthesis of (-)-cyanthiwigin F by means of double catalytic enantioselective alkylation
Double catalytic enantioselective transformations are powerful synthetic methods that can facilitate the construction of stereochemically complex molecules in a single operation. In addition to generating two or more stereocentres in a single reaction, multiple asymmetric reactions also impart increased enantiomeric excess to the final product in comparison with the analogous single transformation. Furthermore, multiple asymmetric operations have the potential to independently construct several stereocentres at remote points within the same molecular scaffold, rather than relying on pre-existing chiral centres that are proximal to the reactive site. Despite the inherent benefits of multiple catalytic enantioselective reactions, their application to natural product total synthesis remains largely underutilized. Here we report the use of a double stereoablative enantioselective alkylation reaction in a concise synthesis of the marine diterpenoid (-)-cyanthiwigin F (ref. 8). By employing a technique for independent, selective formation of two stereocentres in a single stereoconvergent operation, we demonstrate that a complicated mixture of racemic and meso diastereomers may be smoothly converted to a synthetically useful intermediate with exceptional enantiomeric excess. The stereochemical information generated by means of this catalytic transformation facilitates the easy and rapid completion of the total synthesis of this marine natural product
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