Formes observables : de la transformation de marques d'amateurisme en figures esthétiques vidéographiques

Les productions d'amateurs, dont le film de famille est la forme consacrée, font l'objet d'intérêt de nombreux cinéastes. On remarque autant leur évocation dans le film expérimental (de Brakhage et Mekas jusqu'à Forgàcs et l'approche du found footage) que dans le champ historique (l'émission La mémoire qui tourne, la série Apocalypse...). Les premiers trouvent dans la confection en amateur une liberté créatrice et formelle, un registre narratif alternatif, une authenticité qui apparaît carencée dans l'abondance des images technologiques. Le second y puise une documentation sensible, d'une grande proximité avec les événements. L'amateurisme de ce type de production donne l'impression qu'elle est mal faite, surtout si on la compare aux façons de faire actuelles: haute définition, valorisation de la qualité technique des images, souvent au détriment de leur contenu poétique et sensible. Les travaux de Roger Odin démontrent au contraire l'efficacité de ces structures composées d'accidentel et d'imperfections, grâce à l'implication active du spectateur dans la réception. La dimension participative de ces structures imparfaites est non négligeable dans un monde noyé dans le visuel. En se faisant l'avocat d'une cinématographie sensible, d'une éthique particulière de la connaissance par le cinéma, qui dépendraient d'une certaine simplicité technique et d'une approche autoréflexive, l'ethnologue François Laplantine appelle une reconsidération importante de notre façon de produire des images dans la sphère artistique. La recherche présentée ici vise à identifier ces manières alternatives de produire des images, à travers une hybridation des registres et des supports. L'obtention de formes esthétiques à partir de marques d'amateurisme, relatives aux limites du filmeur ou de ses outils, en représente le principal objectif. Le film de famille y est analysé comme forme emblématique de la production sur le mode amateur. Ce mode est un point de départ pour une création vidéographique qui prend ses distances face aux dispositifs hautement spécialisés des productions professionnelles. L'identification psychologique du spectateur à travers une soumission de l'image aux systèmes narratifs traditionnels y est largement négligée au profit d'une identification au dispositif qui encourage une posture plus participative dans la construction du sens. La présente création, intitulée Formes Observables, résulte d'une approche formelle cherchant à exploiter davantage les ressources sensibles du spectateur, à susciter un rapport individuel et collectif au monde à travers la vidéo. Par des structures fragmentaires et formelles, cette série de courtes bandes fait interagir l'expérience esthétique pure et la puissance sensuelle contenue dans la forte dimension référentielle des images en mouvement. De nombreuses stratégies convient la mémoire du monde du spectateur, son rapport sensible à la matérialité qui le compose. L'autoréflexivité des support, équivalant à la mise en avant de l'acte perceptif ainsi que le remploi sont les grandes lignes qui orientent cette production

Using Biofeedback while Immersed in a Stressful Videogame Increases the Effectiveness of Stress Management Skills in Soldiers

This study assessed the efficacy of using visual and auditory biofeedback while immersed in a tridimensional videogame to practice a stress management skill (tactical breathing). All 41 participants were soldiers who had previously received basic stress management training and first aid training in combat. On the first day, they received a 15-minute refresher briefing and were randomly assigned to either: (a) no additional stress management training (SMT) for three days, or (b) 30-minute sessions (one per day for three days) of biofeedback-assisted SMT while immersed in a horror/first-person shooter game. The training was performed in a dark and enclosed environment using a 50-inch television with active stereoscopic display and loudspeakers. On the last day, all participants underwent a live simulated ambush with an improvised explosive device, where they had to provide first aid to a wounded soldier. Stress levels were measured with salivary cortisol collected when waking-up, before and after the live simulation. Stress was also measured with heart rate at baseline, during an apprehension phase, and during the live simulation. Repeated-measure ANOVAs and ANCOVAs confirmed that practicing SMT was effective in reducing stress. Results are discussed in terms of the advantages of the proposed program for military personnel and the need to practice SMT

Adjustment trajectories during the college transition : types, personal and family antecedents, and academic outcomes

This longitudinal study was aimed to describe and understand student adjustment trajectories during the college transition. Participants came from a large random sample of Quebec high school students. They completed a multidimensional measure of adjustment at two times before entering college and at two other times after college admission. Group-based trajectory analysis showed decreased adjustment for 6% (social adjustment) to 66.1% (academic adjustment) of students over this period, versus improved adjustment for 4.5% (social adjustment) to 11.6% (emotional and academic adjustment). All changes were linear, suggesting progressive changes from Secondary 4 to the second year of college. Multivariate and contingency analyses showed that personal anxiety, academic success, and attention problems in high school were significant determinants for adjustment trajectories, and that these trajectories were subsequently related to perseverance and college graduation

Evaluation of the safety of multiple intramuscular doses of ketoprofen in bearded dragons (Pogona vitticeps)

Cyclooxygenase (COX) 1 has been shown to increase significantly in inflamed ophidian skin and chelonian muscles. Nonselective COX-1 and COX-2 inhibitors, such as ketoprofen, could therefore reduce inflammation more effectively than preferential COX-2 inhibitors in reptiles. The objective of this study was to evaluate potential adverse effects of ketoprofen in bearded dragons (Pogona vitticeps). Thirteen adult bearded dragons were divided into three groups receiving daily intramuscular injections for 14 days in a blinded randomized study design. Group 1 (n = 5) received saline, Group 2 (n = 4) received ketoprofen at 2 mg/kg (diluted 1:10 with saline) and Group 3 (n = 4) received ketoprofen at 20 mg/kg (undiluted). Biochemical values, fecal occult blood (FOB) tests, and blood clotting time were assessed before and after the 2-wk treatment. Renal, digestive, hepatic, and muscular histopathology was evaluated. Clinically, injection-site reactions were noted in Group 3 only (n = 1/4). No other clinical adverse effects were detected. No changes were detected in plasma biochemical values and clotting times before and after treatments, nor were changes detected between control and treatment groups. No lesion associated with ketoprofen toxicity was detected on histologic examination of the kidney, liver, and gastrointestinal tract. Lesions of muscular necrosis at the injection sites were of higher magnitude in Group 3 compared to Group 1. In conclusion, daily intramuscular administration of diluted ketoprofen at 2 mg/kg for 14 days did not cause adverse effects in a small number of bearded dragons, whereas severe muscular necrosis was detected at 20 mg/kg

Heterogeneity in the development of proactive and reactive aggression in childhood : Common and specific genetic-environmental factors

Background Few studies are grounded in a developmental framework to study proactive and reactive aggression. Furthermore, although distinctive correlates, predictors and outcomes have been highlighted, proactive and reactive aggression are substantially correlated. To our knowledge, no empirical study has examined the communality of genetic and environmental underpinning of the development of both subtypes of aggression. The current study investigated the communality and specificity of genetic-environmental factors related to heterogeneity in proactive and reactive aggression’s development throughout childhood. Methods Participants were 223 monozygotic and 332 dizygotic pairs. Teacher reports of aggression were obtained at 6, 7, 9, 10 and 12 years of age. Joint development of both phenotypes were analyzed through a multivariate latent growth curve model. Set point, differentiation, and genetic maturation/environmental modulation hypotheses were tested using a biometric decomposition of intercepts and slopes. Results Common genetic factors accounted for 64% of the total variation of proactive and reactive aggression’s intercepts. Two other sets of uncorrelated genetic factors accounted for reactive aggression’s intercept (17%) on the one hand, and for proactive (43%) and reactive (13%) aggression’s slopes on the other. Common shared environmental factors were associated with proactive aggression’s intercept (21%) and slope (26%) and uncorrelated shared environmental factors were also associated with reactive aggression’s slope (14%). Common nonshared environmental factors explained most of the remaining variability of proactive and reactive aggression slopes. Conclusions A genetic differentiation hypothesis common to both phenotypes was supported by common genetic factors associated with the developmental heterogeneity of proactive and reactive aggression in childhood. A genetic maturation hypothesis common to both phenotypes, albeit stronger for proactive aggression, was supported by common genetic factors associated with proactive and reactive aggression slopes. A shared environment set point hypothesis for proactive aggression was supported by shared environmental factors associated with proactive aggression baseline and slope. Although there are many common features to proactive and reactive aggression, the current research underscores the advantages of differentiating them when studying aggression

Persistence and innovation effects in genetic and environmental factors in negative emotionality during infancy : a twin study

Background Difficult temperament in infancy is a risk factor for forms of later internalizing and externalizing psychopathology, including depression and anxiety. A better understanding of the roots of difficult temperament requires assessment of its early development with a genetically informative design. The goal of this study was to estimate genetic and environmental contributions to individual differences in infant negative emotionality, their persistence over time and their influences on stability between 5 and 18 months of age. Method Participants were 244 monozygotic and 394 dizygotic twin pairs (49.7% male) recruited from birth. Mothers rated their twins for negative emotionality at 5 and 18 months. Longitudinal analysis of stability and innovation between the two time points was performed in Mplus. Results There were substantial and similar heritability (approximately 31%) and shared environmental (57.3%) contributions to negative emotionality at both 5 and 18 months. The trait's interindividual stability across time was both genetically- and environmentally- mediated. Evidence of innovative effects (i.e., variance at 18 months independent from variance at 5 months) indicated that negative emotionality is developmentally dynamic and affected by persistent and new genetic and environmental factors at 18 months. Conclusions In the first two years of life, ongoing genetic and environmental influences support temperamental negative emotionality but new genetic and environmental factors also indicate dynamic change of those factors across time. A better understanding of the source and timing of factors on temperament in early development, and role of sex, could improve efforts to prevent related psychopathology

Spatio-temporal requirements for transposable element piRNA-mediated silencing during Drosophila oogenesis

International audienceDuring Drosophila oogenesis, transposable element (TE) repression involves the Piwi-interacting RNA (piRNA) pathway which ensures genome integrity for the next generation. We developed a transgenic model to study repression of the Idefix retrotrans-poson in the germline. Using a candidate gene KD-approach, we identified differences in the spatio-temporal requirements of the piRNA pathway components for piRNA-mediated silencing. Some of them (Aub, Vasa, Spn-E) are necessary in very early stages of oogenesis within the germarium and appear to be less important for efficient TE silencing thereafter. Others (Piwi, Ago3, Mael) are required at all stages of oogenesis. Moreover, during early oogenesis, in the dividing cysts within the germarium, Idefix anti-sense transgenes escape host control, and this is associated with very low piwi expression. Silencing of P-element-based transgenes is also strongly weakened in these cysts. This region, termed the 'Piwiless pocket' or Pilp, may ensure that new TE insertions occur and are transmitted to the next generation, thereby contributing to genome dynamics. In contrast, piRNA-mediated silencing is strong in germline stem cells in which TE mobilization is tightly repressed ensuring the continued production of viable germline cysts

WOod OPtical Scope (WOOPS) : Détermination des propriétés du bois par interaction lumineuse interprétation, mesure et identification des mécanismes et des paramètres d'influence

Le bois sera l'un des matériaux de construction de base du 21ème siècle. Ses propriétés de légèreté, de rigidité, d'isolation et sa capacité à capturer le carbone font de lui un matériau incontournable dans le contexte actuel, où les préoccupations écologiques sont omniprésentes. Une de ses particularités réside dans sa structure multi-échelle complexe et hétérogène qui résulte de la croissance adaptative et singulière d’un arbre dans son environnement (Figure 1). Comme toute ressource issue du vivant, sa variabilité naturelle est très forte et représente un enjeu essentiel dans sa valorisation comme matériau de construction, d’emballage ou d’aménagement intérieur ou extérieur. Les pays nordiques, aidés par l'homogénéité de leur ressource forestière, ont su industrialiser sa transformation et inonder le marché français si bien que près d’une planche sur deux mise en œuvre sur notre territoire est importée. Le principal frein à l’utilisation de bois local dans la construction réside dans la difficulté à prédire ses propriétés mécaniques du fait de son hétérogénéité intrinsèque plus forte que celle des bois du nord. En particulier, la construction à partir de bois feuillus, qui représentent les 2/3 de notre ressource, est aujourd'hui freinée par la complexité à modéliser leur comportement mécanique. Le premier paramètre d'hétérogénéité du bois réside dans l'orientation de ses fibres, qui gouverne ses propriétés mécaniques et physiques. La connaissance de cette orientation pour un placage ou un sciage peut améliorer son usage. Aujourd'hui, cette mesure peut être réalisée par des techniques laser et l'effet trachéide : lorsqu'un point laser rouge est appliqué sur une surface de bois, la lumière se distord et une ellipse est observée chez les résineux dont le grand axe suit les fibres. Ce phénomène, peu coûteux à instrumenter, peut être utilisé pour développer des modèles de comportement mécanique et de séchage. La plupart des auteurs se contente de l'utiliser et personne n'a véritablement publié sur le potentiel réel de l'exploitation de cet effet qui est considérable pour valoriser les bois locaux riches en nœuds