32 research outputs found

    WEBSAGE: a web tool for visual analysis of differentially expressed human SAGE tags

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    The serial analysis of gene expression (SAGE) is a powerful method to compare gene expression of mRNA populations. To provide quantitative expression levels on a genome-wide scale, the Cancer Genome Anatomy Project (CGAP) uses SAGE. Over 7 million SAGE tags, from 171 human cell types have been assembled. The growing number of laboratories involved in SAGE research necessitates the use of software that provides statistical analysis of raw data, allowing the rapid visualization and interpretation of results. We have created the first simple tool that performs statistical analysis on SAGE data, identifies the tags differentially expressed and shows the results in a scatter plot. It is freely available and accessible at

    Profiling writers: analysis of writing dynamics among college students

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    International audienceWe studied the processes involved in synthesis writing, focusing on planning,editing and self-regulation strategies. The aims of the study were a) to analyse thetemporal distribution of cognitive strategies and self-regulation across the differentphases of writing, b) to identify different writing approaches (i.e., profiles), and c) toestablish the relationship between writing behavior and writing performance. Twenty-seven humanities students, who were 23 years of age on average, were asked toproduce a synthesis. The methodology combined videotaped observations, a think aloudprotocol, and an assessment of writing performance, and specific instruments wereconstructed to collect the data. Algorithms were also calculated to determine thetransitions between different types of writing behavior. Results showed that the nature,frequency, and duration of planning, editing, and self-regulation strategies variedaccording to the phase (prewriting or writing), and the most remarkable changesoccurred in the final period of writing. Moreover, although the college students’functioning generally reflected a novice approach, there were significant differencesbetween the three writer profiles we found, namelyprecise transcriber, active reviser,and spontaneous writer. Finally, writing performance was positively and significantlycorrelated with writing strategies such as taking notes and reading drafts

    Disponibilité des textes et performances en compréhension écrite à l’adolescence : quelle implication des fonctions exécutives ?

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    International audienceLes définitions récentes de la lecture insistent sur la nécessaire prise en compte du contexte dans lequel se réalise cette activité. Dans cette perspective, l’objectif de cette étude était d’étudier l’influence de deux situations de lecture (lire un texte en sachant que celui-ci restera – ou non – disponible au moment de répondre à des questions de compréhension) et des stratégies de lecture qui en découlent (intégrale vs. sélective) sur les performances en compréhension d’adolescents de 13-14 ans, et d’examiner le rôle différencié des fonctions exécutives dans ces deux situations. Les résultats montrent que la disponibilité des textes interagit avec les propriétés des textes (uniques vs. multiples) et des questions (bas vs. haut niveau). Par ailleurs, les compétences exécutives semblent préférentiellement impliquées dans les situations où le lecteur garde les textes à disposition au moment de répondre aux questions, suggérant qu’une telle situation relève d’une activité de lecture plus stratégique

    Working Memory, Cognitive Load and Cardiorespiratory Fitness: Testing the CRUNCH Model with Near-Infrared Spectroscopy

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    The present study aimed to examine the effects of chronological age and cardiorespiratory fitness (CRF) on cognitive performance and prefrontal cortex activity, and to test the compensation-related utilization of neural circuits hypothesis (CRUNCH). A total of 19 young adults (18⁻22 years) and 37 older ones (60⁻77 years) with a high or low CRF level were recruited to perform a working memory updating task under three different cognitive load conditions. Prefrontal cortex hemodynamic responses were continuously recorded using functional near-infrared spectroscopy, and behavioral performances and perceived difficulty were measured. Results showed that chronological age had deleterious effects on both cognitive performance and prefrontal cortex activation under a higher cognitive load. In older adults, however, higher levels of CRF were related to increased bilateral prefrontal cortex activation patterns that allowed them to sustain better cognitive performances, especially under the highest cognitive load. These results are discussed in the light of the neurocognitive CRUNCH model

    Load-Dependent Prefrontal Cortex Activation Assessed by Continuous-Wave Near-Infrared Spectroscopy during Two Executive Tasks with Three Cognitive Loads in Young Adults

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    International audienceThe present study examined the evolution of the behavioral performance, subjectively perceived difficulty, and hemodynamic activity of the prefrontal cortex as a function of cognitive load during two different cognitive tasks tapping executive functions. Additionally, it investigated therelationships between these behavioral, subjective, and neuroimaging data. Nineteen right-handed young adults (18–22 years) were scanned using continuous-wave functional near-infrared spectroscopy during the performance of n-back and random number generation tasks in three cognitiveload conditions. Four emitter and four receptor optodes were fixed bilaterally over the ventrolateral and dorsolateral prefrontal cortices to record the hemodynamic changes. A self-reported scale measured the perceived difficulty. The findings of this study showed that an increasing cognitive loaddeteriorated the behavioral performance and increased the perceived difficulty. The hemodynamic activity increased parametrically for the three cognitive loads of the random number generation task and in a two-back and three-back compared to a one-back condition. In addition, the hemodynamic activity was specifically greater in the ventrolateral prefrontal cortex than in the dorsolateral prefrontal cortex for both cognitive tasks (random number generation and n-back tasks). Finally, the results highlighted some links between cerebral oxygenation and the behavioral performance, but not the subjectively perceived difficulty. Our results suggest that cognitive load affects the executive performance and perceived difficulty and that fNIRS can be used to specify the prefrontal cortex’s implications for executive tasks involving inhibition and working memory updating

    Influence of assignment on the prediction of transmembrane helices in protein structures.

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    International audienceα-Helical transmembrane proteins (TMPα) are composed of a series of helices embedded in the lipid bilayer. Due to technical difficulties, few 3D structures are available. Therefore, the design of structural models of TMPα is of major interest. We study the secondary structures of TMPα by analyzing the influence of secondary structures assignment methods (SSAMs). For this purpose, a published and updated benchmark databank of TMPα is used and several SSAMs (9) are evaluated. The analysis of the results points to significant differences in SSA depending on the methods used. Pairwise comparisons between SSAMs led to more than 10% of disagreement. Helical regions corresponding to transmembrane zones are often correctly characterized. The study of the sequence-structure relationship shows very limited differences with regard to the structural disagreement. Secondary structure prediction based on Bayes' rule and using only a single sequence give correct prediction rates ranging from 78 to 81%. A structural alphabet approach gives a slightly better prediction, i.e., only 2% less than the best equivalent approach, whereas the prediction rate with a very different assignment bypasses 86%. This last result highlights the importance of the correct assignment choice to evaluate the prediction assessment
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