We image 104 newly identified low-mass (mostly M-dwarf) pre-main sequence (PMS) members of nearby young moving groups (YMGs) with Magellan Adaptive Optics (MagAO) and identify 27 stellar binaries with instantaneous projected separation as small as 40 mas. Fifteen were previously unknown. The total number of multiple systems in this sample including spectroscopic and visual binaries from the literature is 36, giving a raw stellar multiplicity rate of at least 35(-4)(+5)% for this population. In the separation range of roughly 1-300 au in which infrared AO imaging is most sensitive, the raw multiplicity rate is at least 24(-4)(+5)% for binaries resolved by the MagAO infrared camera (Clio). The M-star subsample of 87 stars yields a raw multiplicity of at least 30(-4)(+5)% over all separations, 21(-4)(+5)% for secondary companions resolved by Clio from 1 to 300 au (23(-4)(+5)% for all known binaries in this separation range). A combined analysis with binaries discovered by the Search for Associations Containing Young stars shows that stellar multiplicity fraction as a function of mass over the range of 0.2 to 1.2M(circle dot) appears to be linearly flat, in contrast to the field, where multiplicity increases with mass. After bias corrections are applied, the multiplicity of low-mass YMG members (0.2-0.6M(circle dot)) is in excess of the field. The overall multiplicity fraction is also consistent with being constant in age and across YMGs, which suggests that multiplicity rates for this mass range are largely set by 10 Myr without appreciable evolution thereafter.

La dopamine du cortex préfrontal (PFC) est impliquée dans l’apprentissage et dans la prise de décision liée à l’effort. Comme l’apprentissage ne peut se faire sans effort, il n’est pas clair aujourd’hui si la dopamine est nécessaire pour l’apprentissage, ou pour l’engagement de l’effort pour apprendre. Dans ce travail, les rats apprenaient à pousser un levier pour obtenir de la nourriture, soit avec (apprentissage par observation, LeO) ou sans (essai-et-erreur, TE) observation préalable d’un congénère exécutant la tâche. TE et la phase d’exécution de LeO nécessitent l’effort physique (overt learning), l’observation dans LeO ne requiert pas d’effort physique (covert learning). Avant chaque session, les rats recevaient des injections de SCH23390 ou de la saline dans le cingulaire antérieur (ACC) ou l’orbitofrontal (OFC). Si la dopamine est nécessaire à l’apprentissage, le blocage des récepteurs D1 affecterait aussi bien l’apprentissage overt que covert. Si la dopamine n’est pas requise pour l’apprentissage mais pour l’engagement de l’effort, le blocage affecterait l’apprentissage overt, et non covert. Les résultats montrent que le blocage de la dopamine dans ACC ou OFC supprime l’apprentissage overt, laissant intact l’apprentissage covert. Une fois les injections arrêtées, les rats récupèrent la capacité d’apprendre, mais dans le cas de ACC, pas la tolérance à l’effort. Ces résultats suggèrent que la dopamine dans ACC et OFC n’est pas nécessaire pour l’apprentissage, et que les déficits d’apprentissage pourraient reflèter une réduction de la tolérance effort à l’effort liée au blocage de la dopamine. / Because prefrontal cortex (PFC) dopamine plays a pivotal role in associative learning and in effort-related decision making, it is not clear as of today whether PFC dopamine activity is required for learning per se, or rather for engaging the effort necessary to learn. In this work, we used observational learning (LeO) and trial-and-error (TE) learning to dissociate learning from physical effort. Both TE and the execution phase of LeO require physical effort (overt learning). Observation does not require physical effort (covert learning). Rats learned to push a lever for food rewards either with or without prior observation of an expert conspecific performing the same task. Before daily testing sessions, the rats received bilateral ACC or OFC microinfusions of SCH23390, or saline-control infusions. If dopamine activity is required for task acquisition, its blockade should impair both overt and covert learning. If dopamine is not required for task acquisition, but solely for regulating effort tolerance, blockade should impair overt learning but spare covert learning. We found that dopamine blockade in ACC or OFC suppressed overt learning selectively, leaving covert learning intact. In subsequent testing sessions without dopamine blockade, rats recovered their overt-learning capacity but, in ACC experiments, the animals did not recover their normal level of effort tolerance. These results suggest that ACC and OFC dopamine is not required for the acquisition of conditioned behaviours and that apparent learning impairments could instead reflect a reduced level of effort tolerance due to cortical dopamine blockade.

A study has been conducted of 12C/13C ratios in five complex molecules in the Galactic center. H2CS, CH3CCH, NH2CHO, CH2CHCN, and CH3CH2CN and their 13C-substituted species have been observed in numerous transitions at 1, 2, and 3 mm, acquired in a spectral-line survey of Sgr B2(N), conducted with the telescopes of the Arizona Radio Observatory (ARO). Between 22 and 54 individual, unblended lines for the 12C species and 2–54 for 13C-substituted analogs were modeled in a global radiative transfer analysis. All five molecules were found to consistently exhibit two velocity components near VLSR ∼ 64 and 73 km s−1, with column densities ranging from Ntot ∼ 3 × 1014 − 4 × 1017 cm−2 and ∼2 × 1013 − 1 × 1017 cm−2 for the 12C and 13C species, respectively. Based on 14 different isotopic combinations, ratios were obtained in the range 12C/13C = 15 ± 5 to 33 ± 13, with an average value of 24 ± 7, based on comparison of column densities. These measurements better anchor the 12C/13C ratio at the Galactic center, and suggest a slightly revised isotope gradient of 12C/13C = 5.21(0.52) DGC + 22.6(3.3). As indicated by the column densities, no preferential 13C enrichment was found on the differing carbon sites of CH3CCH, CH2CHCN, and CH3CH2CN. Because of the elevated temperatures in Sgr B2(N), 13C isotopic substitution is effectively “scrambled,” diminishing chemical fractionation effects. The resulting ratios thus reflect stellar nucleosynthesis and Galactic chemical evolution, as is likely the case for most warm clouds.

Observations provided from RPC-ICA in combination with the data from RPC-MAG and ROSINA-COPS show that many aspects of the time variability of the detected ions is correlated with the magnetic field or -- to a smaller extent -- with neutral atmosphere density. We also show that not all changes in the cometary ion data reflect the nature of the plasma dynamics, but are a consequence of the instrumental limitations. The main outcome of the article in Appendix 1 is that the cometary ions can be divided into two populations with distinct characteristics. One population we termed the convecting population, is accelerated to higher energies through the interaction with the solar wind. The other population we termed the expanding population is moving radially away from the nucleus in the terminator plane. Both populations exhibit a significant anti-sunward component.In addition we present in this thesis a case with observations day-side of the terminator plane. There we show how the expanding population has a sunward component, consistent with initial radial expansion of the ions from the nucleus which gradually turn into an anti-sunward flow which is then observed in the terminator plane.

An investigation is presented of the dust scattering in the coma of 67P/Churyumov-Gerasimenko for the dates of 2015 February 28, March 15 and April 27. A comparison of the morphology of dust continuum maps at 1.1 mu m and gas emission shows that for the above dates the spatial distribution of the dust is strongly correlated with H2O but not with CO2 emission. For April 27, the radial profile on the illuminated side of the nucleus in the inner coma agrees well with the direct simulation Monte Carlo (DSMC) calculations as the dust is accelerating and flows outwards distribution of the dust is narrower than the broader emission of the gas. Af. values are 1.13 m for 2015 February 28, 2.02 m for April 27, while local values for March 15 are 2.3-5.3 m, depending on the nucleus illumination. In the inner coma, the spectral reflectivity from 0.35 to 3.5 mu m displays a red slope with a change at around 1 mu m. From 0.35 to 0.8 mu m, the values range from 9 to 12 +/- 1 per cent per 100 nm both on the sunlit side and on the dark side. From 1 to 2.5 mu m, the values are 1.7 +/- 0.2 per cent per 100 nm on the sunlit side and 3 +/- 1 per cent per 100 nm on the dark side. For the August 26 jet, no significant increase of the colour gradient with distance from the nucleus could be observed, nor any significant difference detected between the jet and the background coma.

Watching oneself on video (self-observation) compared to self-observation coupled with a skilled model video (mixed-models) was examined in a gymnastics environment to determine whether combining two model types would be better than just one. Twenty-one gymnasts learned one gymnastics skill with mixed-models and a second skill with self-observation across pre-test, three learning sessions, and post-test. Physical performance, scored by two evaluators, revealed a significant condition by session interaction (F(3,51) = 3.329, p = .027). At session 3 and post-test, scores obtained with mixed-models were significantly higher than those with self-observation. Cognitive representation of the skills was measured at pre-test and post-test via error detection and recognition tests, analyzed using signal detection. Participants had significantly higher response sensitivity scores with mixed-models (F(1,14) = 10.810, p = .005) compared to self-observation. The conclusion drawn is that it is better to incorporate self and skilled models in a gymnastics setting than self-observation alone.

Recent research suggests that sedentary behaviours have detrimental effects on the health and well-being of children, including effects on obesity. Specifically, television viewing is consistently associated with childhood obesity. Two explanations have been proposed: 1) reduced energy expenditure, and 2) increased food intake. However, it has been suggested that the association between television viewing and childhood obesity may be better explained by an increase in energy intake than by a reduction in energy expenditure. To date, children of different weight status have not been compared in their dietary patterns in front of the television, and it is not known if total sedentary time is linked with food intake in children. The objectives of this thesis are: 1) to determine if obese children consume food more frequently while watching television than normal weight children, and 2) to examine which of television viewing or total sedentary time better predicts dietary patterns in children. Overall, our results re-affirm the notion that television viewing is associated with obesity, although physical activity plays a role in this association. Also, children who are obese consume fast food and fruits/vegetables more frequently during television watching than normal weight children. Furthermore, television viewing appears to be a better predictor of dietary patterns in children than overall sedentary time. Globally, these results provide evidence for the deleterious effects of television viewing on children’s dietary patterns and justification for future intervention studies designed to reduce television viewing in children with obesity.

L’apprentissage chez l’enfant avec autisme est une question qui est souvent abordéedans le cadre des interventions et des prises en charge. Les recherches qui tententd’apprécier l’efficacité de ces interventions ont des résultats contradictoires .Dans notrerecherche nous allons nous intéresser à l’apprentissage par observation chez l’enfant avecautisme. Nous allons appliquer le protocole utilisé par jacqueline Nadel,un protocolequi s’étale sur 9 jours. Après avoir décrit les caractéristiques de notre échantillon etl’intervention. Nous allons comparer les performances des enfants dans ce type d’apprentissageavec les enfants neurotypiques. Par la suite nous allons tester l’efficacité d’un entrainementvisuel sur les performances des enfants avec autisme. Enfin nous allons évaluer l’efficacitéde cette intervention sur le développement moteur des enfants avec autisme et les caractéristiquesqui peuvent influencer l’amélioration de la motricité. Nos résultats ont montré que lesenfants avec autisme peuvent apprendre en observant mais leurs performances moinsbonnes que ceux des enfants neurotypiques . L’entrainement visuel n’a pasamélioré lesperformances des enfants avec autisme car ils ont besoin d’un feedback proprioceptifpendant l’apprentissage. Enfin cette intervention a amélioré le développement moteur desenfants avec autisme mais cette amélioration semble liée à l’intensité de l’autisme / Learning in children with autism is a question that is often addressed through interventionsand load tap. Researches who try to evaluate the effectiveness of these actions havecontradictory results. In our research we will be interested in observational learning inchildren with autism. We will apply the protocol used by Jacqueline Nadel which lasts 9days After describing the characteristics of our sample and intervention.We will comparechildren’s performance in this type of learning with neurotypical children. Then we willtest the effectiveness of a visual training on the performance of children with autism.Then we will evaluate the effectiveness of this intervention on the motor development ofchildren with autism, and characteristics that may influence the improvement of motricityOur results showed that children with autism can learn by watching but not as good astheir neurotypical children performance visual training did not improve the performanceof children with autism because they need proprioceptive feedback during learning.Finally this intervention improved motor development of children with autism but theimprovement seems to be related to the intensity of autism

Os efeitos da demonstração na aprendizagem motora tem sido objeto de estudo de longa data. Porém, o efeito da demonstração autocontrolada e das formas de utilização da possibilidade de autocontrolar esse fator ainda são pouco explorados na literatura. Dessa forma, quatro questões de estudo foram formuladas: 1) qual o efeito da demonstração autocontrolada na aprendizagem de uma habilidade motora seriada? 2) há diferença na aprendizagem entre aqueles que gastam mais tempo para tomar a decisão sobre pedir a demonstração e aqueles que gastam menos tempo? 3) há diferença na aprendizagem entre aqueles que processam a informação observada de forma mais rápida e aqueles que processam de forma mais lenta? 4) há diferença na aprendizagem entre aqueles que mais demonstrações pedem e aqueles que menos pedem? Para investigar essas questões, quatros estudos foram realizados com a participação de 120 indivíduos voluntários, universitários, de ambos os sexos. A tarefa de aprendizagem foi uma habilidade motora seriada que consistiu em movimentar com o mouse um quadrado vermelho, exibido na tela de um computador, de forma a tocar sequencialmente todos os alvos retangulares apresentados na tela, em um determinado padrão temporal. O Estudo 1 envolveu a formação de dois grupos: Auto (demonstração autocontrolada, n=60) e Yoked (demonstração espelhada a partir do grupo Auto, n=60). O experimento consistiu de quatro etapas: fase de aquisição (100 tentativas de prática); teste de retenção 24 horas (20 tentativas); teste de transferência 50 (20 tentativas); teste de transferência 100 (20 tentativas). Os Estudos 2 e 3 foram realizados com a participação de 40 e o Estudo 4 com a participação de 38 indivíduos, todos do grupo Auto do Estudo 1. Para cada um desses estudos foram selecionados participantes que obtiveram valores extremos para as variáveis: Tempo para Tomada de Decisão (TTD), Tempo de Processamento da Informação Observada (TPIO) e quantidade de Demonstrações (DEM). Para a verificação da aprendizagem, o Erro Relativo (ER), Erro Total (ET), Erro Absoluto (EA) e Erro na Sequência (ES) foram medidos. Também foram adotadas medidas complementares para a verificação de como os participantes se envolveram no processo. Com relação ao Estudo 1, os principais resultados foram: a) a superioridade do grupo Auto sobre o Yoked, especialmente, quanto ao ER e o EA; b) o grupo Auto processou por mais tempo a informação observada que o grupo Yoked; c) as demonstrações foram requeridas no início da prática, momento em que o desempenho era significativamente baixo, em ambos os grupos; d) o grupo Yoked se mostrou satisfeito com o momento em que recebeu as demonstrações. Os resultados dos Estudos 2, 3 e 4 mostraram, em síntese, que: a) o gasto de mais tempo tomando a decisão sobre pedir a demonstração promoveu melhor aprendizagem que a condição de gasto menor; b) ambos os grupos, formados a partir da variável Tempo de Processamento da Informação Observada (TPIO), aprenderam de forma semelhante; c) o grupo + DEM teve aprendizagem superior ao DEM em todas as medidas de desempenho. A partir desses resultados concluiu-se que a demonstração autocontrolada produziu melhor aprendizagem que a condição externamente controlada, sendo o Tempo para a Tomada de Decisão e a Quantidade de Demonstração, fatores determinantes dessa superioridade / The effects of demonstration on motor learning have been studied for a long time. However, the effect of self-controlled demonstration and the strategies of the learner in this process have been little explored in the literature. Thus, four questions for study were posed: 1) what is the effect of self-controlled demonstration on learning of a serial motor skill? 2) are there learning differences between the learners that spend more time and the learners that spend less time in making a decision about asking for a demonstration? 3) are there differences in the motor learning process between learners that spend more time and the learners that spend less time in processing the demonstration information? 4) are there differences in the motor learning process between learners that ask for more and the learners that ask for less demonstration in the acquisition phase? To investigate these questions four studies were designed involving 120 volunteer university students of both sexes. A timing task was used whose objective was to manipulate the mouse to move a red square on the computer screen so as to touch, in a sequential manner, all the rectangular targets shown on the screen in a determined temporal pattern. Study One was designed with two groups: Self (self-controlled visual model, n=60) and Yoked (control, n=60). The experiment consisted with four stages: acquisition phase (100 practice trials); retention test, 24 hours after acquisition phase (20 trials); transfer test 50 (20 trials); and transfer test 100 (20 trials). The other three studies were performed with participants from the Self group of Study One with 40 subjects being selected for Study Two and Study Three and 38 subjects for Study Four. Subjects were selected according to those that achieved extreme values for the variables of decision-making time, time for processing the demonstration information, and number of demonstrations. To assess motor learning, relative error, total error, absolute error and sequence error were measured. Complementary measures were also adopted to verify how the participants were involved in the process. In relation to Study One, results indicated: a) superiority of the Self group over the Yoked group, especially in relation to relative error and absolute error; b) the Self group processed the demonstration information for a longer time than the Yoked group; c) demonstration was requested at the beginning of practice, a time at which performance was poor for both groups; and d) the Yoked group was satisfied at the time the demonstration was presented. In short, the results of the Studies Two, Three and Four showed that: a) the more time spent in decision making on requesting demonstration, the better the learning of a sequential motor skill; b) the motor learning of both groups formed through time for demonstration information processing was similar; c) the group that asked for more demonstration learned better than the group that asked for less. Based on these results, it may be concluded that the self-controlled demonstration condition promoted better motor learning than the externally-controlled condition, with decision making time and the amount of demonstration being decisive factors in this respect

Les études de pharmacoépidémiologie consistent à étudier l’effet de médicaments en vie réelle, et sont menées de plus en plus souvent sur bases de données médico-administratives. Ce sont principalement des études observationnelles, et sont donc soumises à des biais liés à des facteurs de confusion. Ces facteurs ne sont pas toujours recueillis dans les bases de données médico-administratives qui sont implémentées à d’autres fins que la recherche. Des plans expérimentaux self-controlled designs (où le patient est son propre témoin, et dont les principaux sont le case-crossover et le self-controlled case-series) permettent d’étudier l’effet transitoire d'expositions brèves sur des évènements à début brutal. Ils sont soumis à certaines conditions d’application. Ils ont la particularité de réaliser des comparaisons sur différentes périodes plutôt que sur différents groupes de patients, permettant ainsi de prendre en compte des facteurs de confusion, y compris non mesurés, et qui ne varient pas entre les périodes observées. Ces méthodes ont montré leur utilité pour pallier l’absence de randomisation, et leur utilisation est recommandée quand leurs conditions d’application sont remplies. Nous avons étudié la fréquence d’utilisation des self-controlled designs en pharmacoépidémiologie sur bases de données, les opportunités manquées d’utilisation et leur usage approprié au regard de leurs conditions d’application, ainsi que la qualité de l’information rapportée dans les articles. Nous avons montré que leur utilisation est rare, que 15% des articles correspondent à des situations d’opportunité où ces méthodes auraient pu être implémentées, que 34% des case-crossover et 13% des self-controlled case-series étaient appliqué de façon inapproprié, et que pour 16% des articles la méthode aurait pu être adaptée pour être valide. Un usage plus approprié permettrait de contribuer à l’investigation en pharmacoépidémiologie tout en bénéficiant des avantages de ces méthodes en particulier sur bases de données de santé. / Pharmacoepidemiology consists in the study of efficacy or safety of drugs in real life, with the use more and more frequently of medico-administrative databases. Study designs are generally observational, thus they are prone to confounding bias. Confounders are not systematically collected in databases, which are implemented for other purposes than research. Self-controlled designs (mainly represented by case-crossover and self-controlled case-series, and in which the patient acts as his own control), have been developed for the study of intermittent exposure with short-term effect on abrupt onset event. They require that validity assumptions being fulfilled. They consist in the comparison over different periods, rather than different groups of patients, thus allowing for confounding factors, also if not measured, which are invariant over observed periods. Such designs have been proved useful in observational studies in the absence of randomization, and their implementation is recommended in case of validity assumptions are fulfilled. We studied their frequency of use in pharmacoepidemiology in healthcare databases, missed opportunities for use, inappropriate use with respect to validity assumptions, as well as quality of reporting. We showed that self-controlled designs are rarely used, that opportunity for use was founds in 15% of articles where such methods could have been implemented, that 34% of case-crossover and 13% of self-controlled case series were inappropriately used, and that the method could have been adapted to be valid in 16% of articles. A more appropriate use of self-controlled designs could contribute to improve investigation in pharmacoepidemiology, while beneficiating from their advantages, especially in healthcare databases.