754 research outputs found

    Mechanical excitation and marginal triggering during avalanches in sheared amorphous solids

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    We study plastic strain during individual avalanches in overdamped particle-scale molecular dynamics (MD) and mesoscale elastoplastic models (EPM) for amorphous solids sheared in the athermal quasistatic limit. We show that the spatial correlations in plastic activity exhibit a short length scale that grows as t3/4 in MD and ballistically in EPM, which is generated by mechanical excitation of nearby sites not necessarily close to their stability thresholds, and a longer lengthscale that grows diffusively for both models and is associated with remote marginally stable sites. These similarities in spatial correlations explain why simple EPMs accurately capture the size distribution of avalanches observed in MD, though the temporal profiles and dynamical critical exponents are quite different

    Die Beziehung zwischen Stiefkindern und Stiefeltern als Folgebeziehung

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    Die Entwicklung familiĂ€rer Beziehungen in Stieffamilien können von Ungleichzeitigkeiten geprĂ€gt sein. So erwarten der wiederverheiratete und der Stiefelternteil Schwierigkeiten mit den Kindern bzw. Stiefkindern eher zu Beginn der Beziehungsaufnahme. Aber in einigen FĂ€llen verlĂ€uft das Zusammenleben in einer ersten Phase der Stieffamilie ĂŒberraschend problemlos. Erst zu einem spĂ€teren Zeitpunkt stellen sich Erziehungs- und Beziehungsprobleme ein, stehen die Eltern vor einem unerwarteten und unverstehbaren PhĂ€nomen. Das unerwartete distanzierte oder gar ablehnende Verhalten des Kindes gegenĂŒber einem oder mehreren Erwachsenen ist eine Folge der Auseinandersetzung des Kindes mit einem LoyalitĂ€tskonflikt, den es gegenĂŒber dem sozialen Stiefelternteil und dem biologischen, aber getrennt lebenden Elternteil empfindet. (TL2

    Blaeu: Mapping and navigating large tables with cluster analysis

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    Blaeu is an interactive database exploration tool. Its aim is to guide casual users through large data tables, ultimately triggering insights and serendipity. To do so, it relies on a double cluster analysis mechanism. It clusters the data vertically: it detects themes, groups of mutually dependent columns that highlight one aspect of the data. Then it clusters the data horizontally. For each theme, it produces a data map, an interactive visualization of the clusters in the table. The data maps summarize the data. They provide a visual synopsis of the clusters, as well as facilities to inspect their content and annotate them. But they also let the users navigate further. Our explorers can change the active set of columns or drill down into the clusters to refine their selection. Our prototype is fully operational, ready to deliver insights from complex databases

    Le niveau de comprĂ©hension de l’anglais des Ă©tudiants en mĂ©decine peut ĂȘtre amĂ©liorĂ©. RĂ©sultats d’une stratĂ©gie d’évaluation systĂ©matique

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    Objectives To describe the level of English of a population of medical students and the improvement after the implementation of systematic assessment that all students achieve a minimal level. Population and methods For the past 5 years, all medical students in our medical school have been taking the Test of English for International Communication (TOEIC). The baseline population (students entering second year in 2004) had no specific obligation. After 2004, a score above 600 was mandatory for graduation. Teaching was oriented towards training for the TOEIC and the number of hours was more important for low-level students. Results The mean score has increased from 618 ± 146 in 2004, to 687 ± 94, 717 ± 97, 733 ± 96 and 731 ± 104 for the next four years. The proportion of students who do not achieve a score of 550 (B1 level of the European framework) has decreased from 30 to 0%. Discussion Improving the level of English of French medical students is possible, if this is made a priority. The objective, as set in engineering studies, that all medical students reach a B2 level would require national guidelines

    In the face of climate change and exhaustive exercise: the physiological response of an important recreational fish species

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    Cobia (Rachycentron canadum) support recreational fisheries along the US mid- and south-Atlantic states and have been recently subjected to increased fishing effort, primarily during their spawning season in coastal habitats where increasing temperatures and expanding hypoxic zones are occurring due to climate change. We therefore undertook a study to quantify the physiological abilities of cobia to withstand increases in temperature and hypoxia, including their ability to recover from exhaustive exercise. Respirometry was conducted on cobia from Chesapeake Bay to determine aerobic scope, critical oxygen saturation, ventilation volume and the time to recover from exhaustive exercise under temperature and oxygen conditions projected to be more common in inshore areas by the middle and end of this century. Cobia physiologically tolerated predicted mid- and end-of-century temperatures (28–32°C) and oxygen concentrations as low as 1.7–2.4 mg l−1. Our results indicated cobia can withstand environmental fluctuations that occur in coastal habitats and the broad environmental conditions their prey items can tolerate. However, at these high temperatures, some cobia did suffer post-exercise mortality. It appears cobia will be able to withstand near-future climate impacts in coastal habitats like Chesapeake Bay, but as conditions worsen, catch-and-release fishing may result in higher mortality than under present conditions

    Neonatal Multisensory Processing in Preterm and Term Infants Predicts Sensory Reactivity and Internalizing Tendencies in Early Childhood.

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    Multisensory processes include the capacity to combine information from the different senses, often improving stimulus representations and behavior. The extent to which multisensory processes are an innate capacity or instead require experience with environmental stimuli remains debated. We addressed this knowledge gap by studying multisensory processes in prematurely born and full-term infants. We recorded 128-channel event-related potentials (ERPs) from a cohort of 55 full-term and 61 preterm neonates (at an equivalent gestational age) in response to auditory, somatosensory, and combined auditory-somatosensory multisensory stimuli. Data were analyzed within an electrical neuroimaging framework, involving unsupervised topographic clustering of the ERP data. Multisensory processing in full-term infants was characterized by a simple linear summation of responses to auditory and somatosensory stimuli alone, which furthermore shared common ERP topographic features. We refer to the ERP topography observed in full-term infants as "typical infantile processing" (TIP). In stark contrast, preterm infants exhibited non-linear responses and topographies less-often characterized by TIP; there were distinct patterns of ERP topographies to multisensory and summed unisensory conditions. We further observed that the better TIP characterized an infant's ERPs, independently of prematurity, the more typical was the score on the Infant/Toddler Sensory Profile (ITSP) at 12 months of age and the less likely was the child to the show internalizing tendencies at 24 months of age. Collectively, these results highlight striking differences in the brain's responses to multisensory stimuli in children born prematurely; differences that relate to later sensory and internalizing functions

    Higher-level goals in the processing of human action events

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    The concept of a goal critically separates dynamic events involving humans from other events. Human behaviours are motivated by goals, which are known to the actor but typically inferred on the part of the observer. Goals can be hierarchical in nature, such that a collection of sub-goals (e.g., getting a mug, boiling water) can be nested under a higher-level goal (e.g., making tea), which can be further nested under an even higher-level goal (e.g., making breakfast). The diverse set of talks in this symposia all highlight the foundational role that goals play in action processing and representation. Eisenberg et al. detail how online prediction of others’ goals shapes observers’ sampling of information during action observation. Howard and Woodward provide evidence that children’s memory for non-human events can be facilitated by priming children with their own goal-directed actions. Loucks and Meltzoff highlight the importance of goal structure in children’s memory for complex action sequences. Finally, Cooper presents a computational model to explain the emergence of goal-directed action hierarchies
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