Monthly Changes in the Composition of Friendship Networks in Early Adolescence

Short-term stability in adolescents’ self-reported friendship networks was examined as a function of (1) participants’ gender, (2) friendship status (best vs. secondary), (3) friendship gender composition (same sex vs. opposite sex), and (4) friendship contexts (school only vs. nonschool only vs. multiple). Adolescents (N = 102) took part in five monthly telephone interviews in which they nominated their friends and provided specific information for each of them. Results indicated that on average, one-third of participants’ nominated friendships in their network were unstable over five months, with girls’ perceived networks being more unstable than boys. Best friendship choices were more stable than secondary ones. Girls’ reports of their opposite-sex friendships were more unstable than boys’, and multicontext friendships (school and nonschool) were more stable than single-context friendships (school only or nonschool only). Results are discussed by highlighting the contribution of short-term assessments in understanding how adolescent networks change over time

Peer group deviancy in organized activities and youths’ problem behaviours

The goal of this study was to examine whether youths’ perceptions of the level of deviancy in their organized activity peer group predicted an increase in their antisocial behaviours and substance use. Their prior behaviour and the level of codeviance with their friends were controlled. Moderators of this association were also examined, including characteristics of youths (i.e., gender) and activity contexts (i.e., type, degree of supervision, age and gender composition of the peer group). Participating youths (N 185; Mage 14.34, 60% girls) were surveyed in Grades 8 and 9 using phone interviews and questionnaires. Results revealed that peer group deviancy predicted increases in youths’ problem behaviours after controlling for covariates. In addition, this association was moderated by the age composition of the activity peer group for antisocial behaviours and by activity type for substance use. Overall, these findings draw attention to the possibility of negative peer group dynamics in organized activities.Le but de cette étude était d’examiner auprès de jeunes si la perception du niveau de déviance des activés organisées de leur groupe d’amis prédisait une augmentation de leurs comportements antisociaux et de leur usage de substances. Leur comportement antérieur et le niveau de déviance commune à leurs amis ont été contrôlés. Les modérateurs de cette association ont aussi été examinés, incluant les caractéristiques des jeunes (c.-à-d., le genre) et le contexte des activités (c.-à-d., le type, le degré de supervision, l’âge et le genre composant le groupe d’amis). Les jeunes participants (N 185, Mâge 14,34, 60% de filles) de secondaire 1 et 2 ont été interrogées via des entrevues téléphoniques et des questionnaires. Les résultats ont révélé que la déviance du groupe d’amis prédit une augmentation des comportements à problème des jeunes après avoir ajusté en fonction des covariables. De plus, cette association était modérée par l’âge des membres du groupe d’amis pour les comportements antisociaux et par le type d’activité pour l’abus de substance. En somme, ces résultats pointent vers la possibilité de dynamiques de groupes négatives lors d’activités organisées

What adolescents experience in organized activities : profiles of individual and social experiences

The goal of this study was to identify profiles of individual (identity, initiative, emotion regulation, and teamwork and social skills) and social experiences (social integration in the activity peer group and support from the activity leader) in organized activities and examine activity-related and youth-related characteristics associated with profile membership. A total of 413 youths (57% girls; Mage = 14.44) involved in 33 different activities were surveyed. Three distinct profiles emerged from the data, characterized by low, average, and high scores on both individual and social experiences, respectively. Membership in these profiles was predicted by the type of activity, the intensity of participation, and the extent to which youths experienced “flow” while participating. Overall, this study revealed that most youths reported high frequencies of positive individual and social experiences in their organized activities and that few activity-related and youth-related characteristics predicted profile membershi

A detailed examination of the longitudinal associations between individual and team sports and alcohol use

This study examined the longitudinal associations between participation in individual and team sports and indicators of alcohol use during the high school years and beyond. A total of 310 youths were surveyed over six waves of data collection (ages 12, 14 to 17, and 19). Participation in individual and team sports was measured through phone interviews, whereas frequency of alcohol use, frequency of intoxication, and problematic alcohol use were self-reported. Control variables included participation in other types of organized activities, sex, family income and structure, parental education and knowledge, problem behaviors, deviant peers, and peer status. The results of autoregressive latent trajectory models revealed reciprocal associations between time spent in individual sports and frequency of alcohol use and intoxication. The results also revealed that time spent in team sports predicted an increase in frequency of alcohol use in middle adolescence. Lastly, the only significant finding at age 19 suggested that the initial number of hours spent in individual sports predicted lower scores on alcohol intoxication. These findings suggest that team sports act as a risk factor for less severe forms of alcohol use in middle adolescence, whereas individual sports act as a protective factor against more severe forms of alcohol use during adolescence and beyond

Other-sex friendships as a mediator between parental monitoring and substance use in girls and boys

Previous research examining relationships between parental monitoring, friendship networks, and substance use did not take into account the gender of both the adolescent and the friends. The goal of this study was to test a mediation model in which having other-sex friends during mid-adolescence mediates the relationships between parental monitoring in early adolescence and substance use during late adolescence. We hypothesized that mediation would be observed for girls but not for boys. A sample of 333 adolescents (60 % girls) was surveyed yearly from ages 12 to 19. The findings provided support for an indirect relationship (mediation via other-sex friendships) between early adolescent parental monitoring and late adolescent alcohol use among girls only. That is, for girls, higher levels of parental monitoring lead to fewer other-sex friendships, which then lead to lower levels of subsequent alcohol use. For drug use, the findings provided support for a direct relationship between early adolescent parental monitoring and late adolescent drug use for both boys and girls. Thus, parents seem to have a protective effect on their daughters’ later use of alcohol by limiting inclusion of male friends in their networks

Intensity and breadth of participation in organized activities during the adolescent years : multiple associations with youth outcomes

The goal of this study was to examine initial levels and rates of change in the intensity and breadth of participation in organized activities during the adolescent years, and how these participation practices were related to youth outcomes in later adolescence. The main objectives were (a) to examine growth curves of intensity and breadth of participation from Grades 7 through 11 and their interrelations, and (b) to test the associations between these dimensions of participation and academic orientation, risky behaviors, internalizing problems, and civic development in Grade 11. A homogenous sample of 299 youth (mean age = 13.37, SD = .41; 62% girls) were surveyed annually using questionnaires and phone interviews. The main results revealed that (a) even though both intensity and breadth of participation decreased over time, intensity of participation showed steeper declines by later grades, and (b) initial levels of participation were better predictors of later outcomes than rates of change over time. Regardless of the levels of change taking place over time, results revealed that youth with high initial levels of participation (both intensity and breadth) were more committed to school and developed more positive values towards society by Grade 11 than those who participated less. This might suggest that a high level of participation during early-to-mid-adolescence is particularly important when it comes to later outcomes

Étude des variations du lien entre l'agressivité et le statut auprès des pairs chez les garçons du primaire

La présente étude s'intéresse aux différences observées d'un milieu à l'autre quant aux liens entre l'agressivité et le statut auprès des pairs chez les garçons. Le modèle de la similarité entre l'individu et le groupe est retenu pour expliquer ce phénomène. Dix-sept classes de troisième année (210 garçons) et quinze classes de cinquième année (193 garçons) ont complété les mesures d'attitude envers l'agressivité, d'évaluation du statut auprès des pairs et d'évaluation du comportement social par les pairs. Une évaluation du comportement de l'enfant par l'enseignant(e) a également été recueillie. Tel qu'attendu, les résultats de la présente étude indiquent que le lien entre l'agressivité et le statut auprès des pairs n'est pas constant et peut varier d'un milieu à l'autre. En troisième année, les résultats observés s'expliquent par le modèle de la similarité. Cependant cette explication ne s'applique pas en cinquième année. La discussion porte principalement sur les résultats observés en cinquième année et suggère qu'ils puissent être attribuables à des différences d'écologie sociale et à l'utilisation d'une procédure inadéquate. Différentes unités d'analyse comme la dyade et le réseau sont proposées comme alternative

Modélisation biomécanique de l'instrumentation chirurgicale du rachis scoliotique

Anatomie descriptive et fonctionnelle du système ostéo-ligamentaire du tronc humain -- Déformations scoliotiques -- Modélisation du rachis scoliotique -- Rappel de la problématique et synthèse des objectifs spécifiques -- Méthodologie générale pour la génération du modèle -- Données peropératoires -- Modélisation cinétique avec mécanismes flexibles du rachis et de l'instrumentation -- Méthode de simulation générale -- Étude de cas -- Étude de sensibilité -- Comparaison entre l'approche cinétique avec mécanismes flexibles et celle par éléments finis -- Évaluation de la segmentation de la tige -- Études de sensibilité -- Comparaison des approches cinétique avec mécanismes flexibles et par éléments finis -- Mesures peropératoires -- Modélisation biomécanique -- Simulation des manoeuvres chirurgicales

Analysis of the co-design activity: influence of a mixed artifact and contribution of the gestural function in a spatial augmented reality environment

International audienceAugmented reality provides new possibilities to propose environments where the designers can take advantage of the physicality of the artifacts while keeping the versatility of digital environments. Mixed objects can therefore provide new media in the interactions between stakeholders. Besides, the increasing interest in user participation in early design phases is limited by the poor representations or the expensive mock ups to be provided in design meetings. Therefore, understanding the role of these mixed artifacts by analyzing and characterizing the interactions is crucial to the development of both design methods and environments. By focusing on multimodal interactions, we aim at providing new results in terms of the design process, in particular by studying the contribution of the gesture in collaborative product co-creativity sessions but also by understanding the role of these multiple interactions in an augmented reality environment