921 research outputs found

    The topological structure of scaling limits of large planar maps

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    We discuss scaling limits of large bipartite planar maps. If p is a fixed integer strictly greater than 1, we consider a random planar map M(n) which is uniformly distributed over the set of all 2p-angulations with n faces. Then, at least along a suitable subsequence, the metric space M(n) equipped with the graph distance rescaled by the factor n to the power -1/4 converges in distribution as n tends to infinity towards a limiting random compact metric space, in the sense of the Gromov-Hausdorff distance. We prove that the topology of the limiting space is uniquely determined independently of p, and that this space can be obtained as the quotient of the Continuum Random Tree for an equivalence relation which is defined from Brownian labels attached to the vertices. We also verify that the Hausdorff dimension of the limit is almost surely equal to 4.Comment: 45 pages Second version with minor modification

    La Dyspraxie développementale

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    #PublierAutrement : Une nécessité / une opportunité

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    L\u27acte de publication est fondateur pour le chercheur comme pour les institutions. Les nouvelles technologies de l\u27information et de la communication permettent d’envisager une révision en profondeur du processus de publication, rendue d’autant plus nécessaire que le modèle économique et même éthique qui sous-tend les modalités actuelles ne sont plus tenables. Et maintenant, quelle montée en puissance pour les e-publications

    Secoviridae: a proposed family of plant viruses within the order Picornavirales that combines the families Sequiviridae and Comoviridae, the unassigned genera Cheravirus and Sadwavirus, and the proposed genus Torradovirus

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    The order Picornavirales includes several plant viruses that are currently classified into the families Comoviridae (genera Comovirus, Fabavirus and Nepovirus) and Sequiviridae (genera Sequivirus and Waikavirus) and into the unassigned genera Cheravirus and Sadwavirus. These viruses share properties in common with other picornavirales (particle structure, positive-strand RNA genome with a polyprotein expression strategy, a common replication block including type III helicase, a 3C-like cysteine proteinase and type I RNA-dependent RNA polymerase). However, they also share unique properties that distinguish them from other picornavirales. They infect plants and use specialized proteins or protein domains to move through their host. In phylogenetic analysis based on their replication proteins, these viruses form a separate distinct lineage within the picornavirales branch. To recognize these common properties at the taxonomic level, we propose to create a new family termed “Secoviridae” to include the genera Comovirus, Fabavirus, Nepovirus, Cheravirus, Sadwavirus, Sequivirus and Waikavirus. Two newly discovered plant viruses share common properties with members of the proposed family Secoviridae but have distinct specific genomic organizations. In phylogenetic reconstructions, they form a separate sub-branch within the Secoviridae lineage. We propose to create a new genus termed Torradovirus (type species, Tomato torrado virus) and to assign this genus to the proposed family Secoviridae

    La dyspraxie développementale : actualités et enjeux

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    This paper provides a review of current knowledge in the field of specific motor coordination and gestural disorders in children, generally referred as two major diagnosis: developmental dyspraxia and Developmental Coordination Disorder (DCD). After few reminders of the main notions, we analyse the controversies regarding the distinction of dyspraxia and DCD. The specificity of dyspraxia’s subtypes is discussed regarding the heterogeneity of deficits and their interpretation. This leads us to propose theoretical and clinical perspectives for a complete assessment enabling to identify all praxic variables contributing to dyspraxia. A better understanding of the nature of praxic disorders reported in children is needed to overcome current limitations, in order to identify the evidence of specific mechanisms and etiology of developmental dyspraxia

    Deficit of cognitive inhibition in depressed elderly: a neurocognitive marker of suicidal risk

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    BACKGROUND: Cognitive deficits, in relation to ventral and dorsal prefrontal cortex dysfunctions, have been associated with a higher risk of suicidal acts in young adult patients. Although a public health concern, much less is known about the neurocognitive basis of suicidal behavior in elderly. Here, we aimed at assessing alterations in cognitive inhibition, a suspected major mechanism of the suicidal vulnerability, in suicidal depressed elderly.METHODS: We compared 20 currently depressed patients, aged 65 and older who recently attempted suicide to 20 elderly subjects with a current depression but no personal history of suicide attempt and 20 elderly controls. Using an extensive neuropsychological battery, we particularly examined different aspects of cognitive inhibition: access to relevant information (using the Reading with distraction task), suppression of no longer relevant information (Trail Making Test, Rule Shift Cards), and restraint of cognitive resources to relevant information (Stroop test, Hayling Sentence Completion test, Go/No-Go). RESULTS: After adjustment for age, intensity of depression, Mini-Mental State Examination score and speed of information processing, suicidal depressed elderly showed significant impairments in all 3 domains of cognitive inhibition in comparison to both control groups. LIMITATIONS: Our results need replication in a larger sample size. CONCLUSIONS: Our study suggests that the inability to inhibit neutral information access to working memory, restrain and delete irrelevant information may impair the patient\u27s capacity to respond adequately to stressful situations subsequently leading to an increased risk of suicidal behavior during late-life depression. Interventions may be developed to specifically target cognitive impairment in the prevention of suicide in depressed elderly
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