The purpose of this study was to analyze the practical knowledge of expert sailing coaches of the French team preparing for the 1996 Olympic Games in Atlanta. Coaching knowledge was studied from a cognitive ergonomics perspective based on the task activity model. According to this model, a task is a set of constraints facing individuals. To meet the demands imposed by these constraints, an individual engages in an adaptative activity which can be studied from the point of view of his or her knowledge and cognitive operating modes. In-depth interviews were conducted after observation of five training sessions, and the verbal protocols obtained were coded inductively. The results showed that coaching tasks were considered by coaches as a set of interacting constraints which generate complex, contradictory, and ill defined problems. Coaches' operating modes appeared to be based on organization routines, cognitive anticipation on flexible plans, flexible on-site adaptation, joint control of training with athletes, and involvement in the training situation based on past experiences.
The elementary topological T1 process in a two-dimensional foam corresponds to the "flip" of one soap film with respect to the geometrical constraints. From a mechanical point of view, this T1 process is an elementary relaxation process through which the entire structure of an out-of-equilibrium foam evolves. The dynamics of this elementary relaxation process has been poorly investigated and is generally neglected during simulations of foams. We study both experimentally and theoretically the T1 dynamics in a dry two-dimensional foam. We show that the dynamics is controlled by the surface viscoelastic properties of the soap films (surface shear plus dilatational viscosity, µs + κ, and Gibbs elasticity ǫ), and is independent of the shear viscosity of the bulk liquid. Moreover, our approach illustrates that the dynamics of T1 relaxation process provides a convenient tool for measuring the surface rheological properties: we obtained ǫ = 32 ± 8 mN/m and µs + κ = 1.3 ± 0.7 mPa.m.s for SDS, and ǫ = 65 ± 12 mN/m and µs + κ = 31 ± 12 mPa.m.s for BSA, in good agreement with values reported in the literature.
Pressure-flow relationships measured in human plastinated specimen of both nasal cavities and maxillary sinuses were compared to those obtained by numerical airflow simulations in a numerical three-dimensional reconstruction issued from CT scans of the plastinated specimen. For experiments, flow rates up to 1,500 ml/s were tested using three different gases: HeO(2), Air, and SF(6). Numerical inspiratory airflow simulations were performed for flow rates up to 353 ml/s in both the nostrils using a finite-volume-based method under steady-state conditions with CFD software using a laminar model. The good agreement between measured and numerically computed total pressure drops observed up to a flow rate of 250 ml/s is an important step to validate the ability of CFD software to describe flow in a physiologically realistic binasal model. The major total pressure drop was localized in the nasal valve region. Airflow was found to be predominant in the inferior median part of nasal cavities. Two main vortices were observed downstream from the nasal valve and toward the olfactory region. In the future, CFD software will be a useful tool for the clinician by providing a better understanding of the complexity of three-dimensional breathing flow in the nasal cavities allowing more appropriate management of the patient's symptoms.
The main aim of this paper is to review Middle Permian through Middle Triassic continental successions in European. Secondly, areas of Middle-Late Permian sedimentation, the Permian-Triassic Boundary (PIB) and the onset of Triassic sedimentation at the scale of the westernmost peri-Tethyan domain are defined in order to construct palaeogeographic maps of the area and to discuss the impact of tectonics, climate and sediment supply on the preservation of continental sediment.At the scale of the western European peri-Tethyan basins, the Upper Permian is characterised by a general progradational pattern from playa-lake or floodplain to fluvial environments. In the northern Variscan Belt domain, areas of sedimentation were either isolated or connected to the large basin, which was occupied by the Zechstein Sea. In the southern Variscan Belt, during the Late Permian, either isolated endoreic basins occurred, with palaeocurrent directions indicating local sources, or basins underwent erosion and/or there was no deposition. These basins were not connected with the Tethys Ocean, which could be explained by a high border formed by Corsica-Sardinia palaeorelief and even parts of the Kabilia microplate. The palaeoflora and sedimentary environments suggest warm and semi-arid climatic conditions. At the scale of the whole study area, an unconformity (more or less angular) is observed almost everywhere between deposits of the Upper Permian and Triassic, except in the central part of the Germanic Basin. The sedimentation gap is more developed in the southern area where, in some basins, Upper Pennian sediment does not occur. The large sedimentary supply, erosion and/or lack of deposition during the Late Permian, as well as the variable palaeocurrent direction pattern between the Middle-Late Permian and the EarlyTriassic indicate a period of relief rejuvenation during the Late Pennian. During the Induan, all the intra-belt basins were under erosion and sediment was only preserved in the extra-belt domains (the northern and extreme southern domains). In the northern domain (the central part of the Germanic Basin), sediment was preserved under the same climatic conditions as during the latest Permian, whereas in the extreme southern domain, it was probably preserved in the Tethys Ocean, implying a large amount of detrital components entering the marine waters. Mesozoic sedimentation began in the early Olenekian; the ephemeral fluvial systems indicate arid climatic conditions during this period.Three distinct areas of sedimentation occur: a northern and southern domain, separated by an intra-belt domain.The latter accumulated sediments during the Early-Middle Permian and experienced erosion and/or no-deposition conditions between the Middle-Late Pennian and the beginning of Mesozoic sedimentation, dated as Anisian to Hettangian. At the top of the Lower Triassic, another tectonically induced, more or less angular unconformity is observed: the Hardegsen unconformity, which is dated as intra-Spathian and is especially found in ...
Motivational research in the classroom has adopted a social cognitive perspective but has mainly been restricted to the study of individual achievement cognitions. In addition to this, there is a need to study and assess the perception children have of the class climate. Using social cognitive theory as a base, this research reports the development of class climate scales in French and English for use in physical education classes. Psychometric development with the French scale was shown to be satisfactory, including adequate factorial structure assessed by exploratory and confirmatory factor analysis (CFA), and good internal and test-retest reliability. A parallel English scale demonstrated a less adequate fit to the proposed model when using CFA, but shortened scales assessing just mastery and performance dimensions of climate were shown to predict important motivational measures in a structural equation modelling analysis.
Contemporary research in the social psychology of sport has used Nicholls' (1984, 1989) social cognitive theory of goal orientations and motivation in order to gain a better understanding of cognitive, affective and behavioural aspects of sport participation. Success can be defined in at least two different ways that lead to two major goal orientations (task/mastery and social comparison), but little is known about why or how such goals may develop, although preliminary research in education links goals to conceptions about the nature of academic ability (i.e. intelligence). Using a similar notion, we studied conceptions of athletic ability by assessing children's representations of sport ability. Two studies were conducted with children and youth in England and France. Initial findings suggested that the methods adopted by Dweck & Leggett (1988) in education, while showing some links between goals and beliefs, are not wholly applicable to sport. In using a more comprehensive measure of sport ability conceptions, we observed clear relationships between a social comparison goal and a conception of athletic ability as a ‘gift’ and being ‘general’, and between a task mastery goal and the conception of athletic ability as being incremental and determined by learning. We develop and discuss the meaning of the causal links that unite goals and ability conceptions, as well as the likely impact of such conceptions on motivation.
We investigated whether the spontaneous transition between walking and running during moving with increasing speed corresponds to the speed at which walking becomes less economical than running. Seven active male subjects [mean age, 23.7 (SEM 0.7) years, mean maximal oxygen uptake (VO2max), 57.5 (SEM 3.3) ml.kg-1.min-1, mean ventilatory threshold (VTh), 37.5 (SEM3) ml.kg-1.min-1] participated in this study. Each subject performed four exercise tests separated by 1-week intervals: test 1, VO2max and VTh were determined; test 2, the speed at which the transition between walking and running spontaneously occurs (ST) during increasing speed (increases of 0.5 km.h-1 every 4 min from 5 km.h-1) was determined; test 3, the subjects were constrained to walk for 4 min at ST, at ST +/- 0.5 km.h-1 and at ST +/- 1 km.h-1; and test 4, the subjects were constrained to run for 4 min at ST, at ST +/- 0.5 km.h-1 and at ST +/- 1 km.h-1. During exercise oxygen uptake (VO2), heart rate (HR), ventilation (VE), ventilatory equivalents for oxygen and carbon dioxide (VE/VO2, VE/VCO2), respiratory exchange ratio (R), stride length (SL), and stride frequency (SF) were measured.(ABSTRACT TRUNCATED AT 250 WORDS)
This study assessed the influence of individual and contextual factors on adolescent girls' interest in school physical education (PE). Specifically, girls (N = 700) were assessed on: (a), perceptions of their PE class climate, using the Perceived Motivational Climate Scale (PMCS, Cury et al., 1994; (b) dispositional achievement goal orientations, using the French version of the Perception of Success Questionnaire (POSQ, Durand et al M in press; and (c) the interest and competence subscales from the French version of the Intrinsic Motivation Inventory (IMI, Cury et al., 1994a). Structural equation modelling analysis, using LISREL VII, showed an excellent fit with the hypothesised model. Specifically, situational class climate was found to be more important than individual goals in influencing pupil interest in PE. However, perceived competence also influenced interest, as did a mastery goal orientation. Results are discussed in the context of theoretical propositions of goal perspectives theory and practical issues of enhancing adolescent girls' interest in physical education.
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