Développement de la connaissance des lettres capitales. Étude transversale chez les enfants français de trois à six ans

The present study examined the knowledge of uppercase letters in 160 children aged from three to six. Three tasks were administrated: letter saying, letter naming, letter recognition. Children's responses were analyzed according to several variables: school level, gender, task, letter type, letter frequency, etc. Letter knowledge improved from three to six years, but with huge differences among children, namely the superiority of girls over boys. Letter by letter analyses showed that scores were highly consistent between tasks and school levels. They also revealed that letter knowledge was affected by letter type, letter frequency, alphabetic rank and the presence of letters in the child's first name. The findings are discussed for their contribution to the understanding of letter learning.     

Nucleation of recrystallization in fine-grained materials: an extension of the Bailey–Hirsch criterion

Abstract

A new criterion for nucleation in the case of dynamic recrystallization is proposed in order to include the contribution of the grain boundary energy stored in the microstructure in the energy balance. Due to the nucleation events, the total surface area of pre-existing grain boundaries decreases, leading to a nucleus size smaller than expected by conventional nucleation criteria. The new model provides a better prediction of the nucleus size during recrystallization of pure copper compared with the conventional nucleation criterion.     

Age-Correlated Incremental Consideration of Velocity Information in Relative Time-to-Arrival Judgments

One hundred fifty-one children and 43 adults judged which of 2 cartoon birds would be the first to arrive at a common finish line. Objects moved unidirectionally along parallel trajectories, either at the same or different speeds, and disappeared at different distances from the goal. Overall, 9–10-year-old children performed as well as adults, but 4–5- and 6–8-year-olds erred significantly more often. On trials for which distance to goal at disappearance was a valid cue, 4–5-year-olds scored 80% correct, and no differences were seen between 6–10-year-olds and adults. On the opposite type of trials, where the trailing bird would win the race, only adults retained their level of performance, and all age groups differed markedly. Findings suggest a gradual developmental transition from a distance-based to a time-based understanding of the task.     

Toward a multidimensional definition of sportsmanship

Abstract

One major problem with research conducted on sportsmanship is the absence of an accepted definition. The purpose of this study was to attempt to derive a definition of sportsmanship by applying premises from social psychological theories and research. A major assumption of this perspective is that sportsmanship meanings and labels attached to given behaviors are learned through interpersonal interactions with various sport participants and that eventually a consensual agreement develops regarding the nature of sportsmanship. It thus follows that a meaningful definition of sportsmanship should be obtained through the athletes themselves. In this study, 1056 male and female athletes completed a questionnaire which contained various items pertaining to sportsmanship. Results from a factor analysis revealed the presence of 5 factors corresponding to the respect and concern for: a) one's full commitment toward sport participation, b) the rules and officials. c) social conventions, d) the opponent, as well as e) a negative approach toward sport participation. Implications of this multidimensional definition for future sportsmanship research are drawn.     

Why We Walk the Way We Do

By using inverse dynamics and forceplate recordings, this study established the principle of oscillating systems and the influence of gravity and body parameters on the programming of the gait parameters, step frequency and length. Calculation of the ratio of the amplitude of the center of mass (CM) and the center of foot pressure (CP) oscillations yielded an equation and established a biomechanical constant, the natural body frequency (NBF). NBF appears to be an absolute invariant parameter, specific to human standing posture and gait in terrestrial gravity, which influences the relative positions of CM and CP and whose value separates the frequency bands of standing posture from those for gait. This equation was tested by using the experimental paradigm of stepping in place and then used in calculating the magnitude of CM oscillations during gait. The biomechanical analysis of the experimental observations allows one to establish the relationships between body parameters and gravity and the central programming of locomotor parameters.     

Postural Requirements and Progression Velocity in Young Walkers

This article describes developmental changes in gait velocity and relates these changes to gait parameters that index postural stability (step width and lateral acceleration) and two components of velocity (cadence and step length).

Five children were observed longitudinally over a 2-year period after onset of independent walking. Their range of speed increased threefold in the first 6 months of independent walking and then remained constant. In contrast, step width decreased approximately twofold. Whereas in adults, cadence and step length contribute approximately equally to speed, when infants first begin to walk independently, increase in velocity is due mostly to increased step length. After 5 months of independent walking, the pattern reverses, and increase in velocity is due primarly to increased cadence. The pattern remains constant over the next 18 months. From a developmental point of view, the data lead us to interpret early walking (the first 5 months) as a process of integration of postural constraints into the dynamic necessities of gait movement. A second phase, beginning after 4 to 5 months of independent walking, is considered to be a tuning phase characterized by a more precise adjustment of the gait parameters.     

Coordination Dynamics of the Bipedal Galloping Pattern

A motion equation in relative phase was developed that incorporates the spatial-temporal pattern of the bipedal gallop along with the more commonplace patterns of the bipedal jump and walk-run. In 3 experiments, human participants (N = 6 per experiment) simulated the bipedal gait patterns through the rhythmic motions of hand-held pendulums. Predictions of the motion equation for coordination equilibria and their respective degrees of stability were confirmed. In particular, the gallop pattern was less stable than the fundamental in-phase and antiphase patterns but changed in qualitatively similar ways to those gaits as a function of limb asymmetry and movement frequency. The relation between the modeled coordination dynamics and the kinematic characteristics of real bipedal galloping is discussed.     

Entrevista con Jean-Paul Bronckart

RESUMEN

Bronckart comienza revisando su trayectoria científica y explicando cuáles son sus dos enfoques básicos: el análisis del contexto o de situaciones y el análisis del lenguaje en función de sus operaciones subyacentes definidas en el marco de las teorías de la enunciación. Seguidamente justifica su renuncia a posiciones estructuralistas porque no tienen en cuenta el problema de las relaciones funcionales ni prestan atención al contexto. El autor relaciona las operaciones psicológicas con universales funcionales diferenciándolos de los estructurales de Chomsky y del enfoque de Searle, defendiendo su interés por la lingüística comparativa. Seguidamente aborda el tema de análisis de textos en ambientes escolares, sugiriendo que hay que sensibilizar a los educadores sobre el hecho de que constantemente estamos en situaciones de comunicación que van cambiando y crear instrumentos para que puedan analizar su propia práctica. Con relación al aspecto cognitivo del lenguaje, enfatiza la proliferación excesiva de los enfoques representativos y seguidamente desarrolla qué entiende por especificidad de la naturaleza del lenguaje y de su carácter comunicativo. Esta entrevista aborda, además, cuestiones tales como el fenómeno presuposicional, las aportaciones de Vygotsky o las experiencias de enseñar lenguaje a chimpancés, y finaliza planteando algunos aspectos de la teoría de Culioli.