Performance attributes of talented schoolboy Australian Rules Football players

The purpose of the study was to investigate the relationship between selected psychological characteristics and performance of a group of talented young Australian Rules football players. The study group consisted of 50 of the best identified schoolboy 15 year old Australian Rules football players in Western Australia. From this group 25 boys were selected to represent Western Australia at the Australian School Sports Council National Football Championships. The selected psychological characteristics were competitive anxiety (trait and state), competitive sport orientation (competitiveness, win and goal orientation) and sport confidence (trait and state). Performance was measured, first, by the selection or non selection of the player in the final team and second, by a high or low performance rating at the completion of the championships. Psychological characteristics of those players who were selected in the team were compared with those who did not make the team in an attempt to identify those characteristics that related to successful team selection. A further comparison of psychological characteristics and performance levels at the completion of the championships was made to determine any common characteristics that identify the higher performing players and possibly to identify predictors of successful performance which could assist with the selection process of other similar groups. The results did not indicate any significant relationships between the selected psychological characteristics of competitive sport orientation, competitive sport anxiety and sport confidence. Nor did the results indicate any relationship between the selected characteristics and the performance of the study group. The results did show however, significant differences between the perceptions of performance as rated by the players themselves and the ratings by the coach, manager, teammates and other independent observer. In every performance rating measure, factor loadings clearly showed that player self-assessments of performance was highly inconsistent with the assessments of the other assessors. This potential area of research may be of significant value in that the player\u27s perception of his performance is not consistent and at variance with the views of the coach and of his teammates

On the formation of string cavitation inside fuel injectors

The formation of vortex or ‘string’ cavitation has been visualised in the flow upstream of the injection hole inlet of an automotive-sized optical diesel fuel injector nozzle operating at pressures up to 2,000 bar. Three different nozzle geometries and three-dimensional flow simulations have been employed to describe how, for two adjacent nozzle holes, their relative positions influenced the formation and hole-to-hole interaction of the observed string cavitation vortices. Each hole was shown to contain two counter-rotating vortices: the first extending upstream on axis with the nozzle hole into the nozzle sac volume and the second forming a single ‘bridging’ string linked to the adjacent hole. Steady-state and transient fuel injection conditions were shown to produce significantly different nozzle-flow characteristics with regard to the formation and interaction of these vortices in the geometries tested, with good agreement between the experimental and simulation results being achieved. The study further confirms that the visualised vortices do not cavitate themselves but act as carriers of gas-phase components within the injector flow

Cleavage and shedding of E-cadherin after induction of apoptosis

Apoptotic cell death induces dramatic molecular changes in cells, becoming apparent on the structural level as membrane blebbing, condensation of the cytoplasm and nucleus, and loss of cell-cell contacts. The activation of caspases is one of the fundamental steps during programmed cell death. Here we report a detailed analysis of the fate of the Ca2+-dependent cell adhesion molecule E-cadherin in apoptotic epithelial cells and show that during apoptosis fragments of E-cadherin with apparent molecular masses of 24, 29, and 84 kDa are generated by two distinct proteolytic activities. In addition to a caspase-3-mediated cleavage releasing the cytoplasmic domain of E-cadherin, a metalloproteinase sheds the extracellular domain from the cell surface during apoptosis. Immunofluorescence analysis confirmed that concomitant with the disappearance of E-cadherin staining at the cell surface, the E-cadherin cytoplasmic domain accumulates in the cytosol. In the presence of inhibitors of caspase-3 and/or metalloproteinases, cleavage of E-cadherin was almost completely blocked. The simultaneous cleavage of the intracellular and extracellular domains of E-cadherin may provide a highly efficient mechanism to disrupt cadherin-mediated cell-cell contacts in apoptotic cells, a prerequisite for cell rounding and exit from the epithelium

Comparaison entre la simulation et les donnees de neutrinos dans BUGEY 3

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : T 84551 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc