Self-belief does make a difference: a reciprocal effects model of the causal ordering of physical self-concept and gymnastics performance

A large body of research in support of the reciprocal effects model of causal ordering demonstrates that prior academic self-concept predicts subsequent academic achievement beyond what can be explained in terms of prior achievement. Here we evaluate the generalizability of this support for the reciprocal effects model to a physical activity context in which achievement is reflected in gymnastics skills on a standardized gymnastics performance test evaluated by expert judges. Based on the responses of 376 adolescents collected at the start (T1) and end (T2) of a gymnastics training programme, there is support for a reciprocal effects model in which there are significant paths leading from both T1 gymnastics self-concept to T2 gymnastics skills and from T1 gymnastics skills to T2 self-concept. Although there were gender and age effects (girls and older participants had better gymnastics skills, boys had higher self-concepts), multiple group structural equation models indicated that support for the reciprocal effects model generalized over responses by boys and girls. In summary, self-concept and performance are both determinants and consequences of each other.     

Examining Change in Cortisol Patterns During the 10‐Week Transition to a New Child‐Care Setting

The transition to out‐of‐home child care brings a number of challenges for children, including complex peer interactions and extended separations from parents. Children often show a midmorning to afternoon rise in cortisol on child‐care days, compared to the typical diurnal decline seen at home. Changes in cortisol were examined in a wide age range of children (N = 168; 1.2 months to 8 years, M = 3.27 years) during the 10‐week transition to a new child‐care setting. Structural equation modeling using latent change scores showed that children experienced an increase in the cortisol rise at child care across the 10‐week transition. Furthermore, child age moderated the difference between home‐ and child‐care cortisol patterns. Findings are placed in a developmental context, and potential implications and future directions are discussed.     

Determination of the centre of mass kinematics in alpine skiing using differential global navigation satellite systems

In the sport of alpine skiing, knowledge about the centre of mass (CoM) kinematics (i.e. position, velocity and acceleration) is essential to better understand both performance and injury. This study proposes a global navigation satellite system (GNSS)-based method to measure CoM kinematics without restriction of capture volume and with reasonable set-up and processing requirements. It combines the GNSS antenna position, terrain data and the accelerations acting on the skier in order to approximate the CoM location, velocity and acceleration. The validity of the method was assessed against a reference system (video-based 3D kinematics) over 12 turn cycles on a giant slalom skiing course. The mean (± s) position, velocity and acceleration differences between the CoM obtained from the GNSS and the reference system were 9 ± 12 cm, 0.08 ± 0.19 m · s^-1 and 0.22 ± 1.28 m · s^-2, respectively. The velocity and acceleration differences obtained were smaller than typical differences between the measures of several skiers on the same course observed in the literature, while the position differences were slightly larger than its discriminative meaningful change. The proposed method can therefore be interpreted to be technically valid and adequate for a variety of biomechanical research questions in the field of alpine skiing with certain limitations regarding position.     

Separation of platelets from other blood cells in continuous-flow by dielectrophoresis field-flow-fractionation

We present a microfluidic device capable of separating platelets from other blood cells in continuous flow using dielectrophoresis field-flow-fractionation. The use of hydrodynamic focusing in combination with the application of a dielectrophoretic force allows the separation of platelets from red blood cells due to their size difference. The theoretical cell trajectory has been calculated by numerical simulations of the electrical field and flow speed, and is in agreement with the experimental results. The proposed device uses the so-called "liquid electrodes" design and can be used with low applied voltages, as low as 10 V(pp). The obtained separation is very efficient, the device being able to achieve a very high purity of platelets of 98.8% with less than 2% cell loss. Its low-voltage operation makes it particularly suitable for point-of-care applications. It could further be used for the separation of other cell types based on their size difference, as well as in combination with other sorting techniques to separate multiple cell populations from each other.     

Approche constructiviste en pédagogie: Décentration et anticipation dans des jeux socio-moteurs

In the constructivist theory, development is the result of an internal process carried on by an individual in interaction with his environment. In the steps of many psychologists and after Piaget in particular, it has been assumed that play contributed to the developmental process of children. This, with regard to the cognitive process, but also to the sociocognitive and motor processes as well. In fact, Kamii and Devriès (1980), when they studied play in young children groups made it clear that children proceed from a self-centered point of view to a conception where several points of view are concerned. This constructivist perspective has been ours when we carried out a pedagogical experiment with 10 years old children of a primary school, using collective play situations for the children to attain a content unknown to them. In this particular sociomotor context, this type of pedagogical approach has been experimented during six sessions with an experimental group of fifteen children. Analysis of the processes of decentration from object and from social object and anticipation has been carried on by means of sociomotor indicators during observation before and after experimentation in the experimental group and in a control group of thirteen children. A greater improvement of both processes was ascertained in the first group and the chosen sociomotor indicators looked like a most appropriate instrument for analysis.     

Public Sector Research: A Growing Role in Innovation Systems

This essay highlights three converging trendsexperienced by `public sector research' duringthe past decade. Looking especially at France,our discussion draws attention to the new rolesof universities, the blurring of relationshipsbetween types of research institutions andresearch activities, and the development of`research collectives' as an organizationalfeature now emerging throughout Europe.