Conjugaison et cyclage dans les groupes de Garside, applications cryptographiques

Ce travail s'inscrit dans la thématique de la cryptographie basée sur les tresses. Nous nous intéressons au problème de conjugaison et au problème des cyclages présentés par K.H. Ko, S.J. Lee et al. à CRYPTO 2000 (LNCS 1880) dans New public-key cryptosystem using braid groups. D'une part, nous montrons que l'inversion de la fonction cyclage admet une solution polynomiale dans les groupes de Garside, qui sont une généralisation des groupes de tresses ; ceci permet de résoudre efficacement le problème des cyclages. D'autre part, le travail réalisé sur le problème de conjugaison et ses variantes met en relief le ro le joué par les générateurs aléatoires de tresses. Nous proposons un algorithme qui donne une factorisation du secret sous la forme d'un diviseur et d'un multiple. Ceci permet de définir deux nouvelles instances dont les secrets sont de taille réduite. De plus, nous exploitons la double structure de Garside des groupes de tresses afin d'améliorer l'efficacité de cette réduction. Nous observons que le choix du générateur aléatoire influe grandement sur la sécurité d'une instance et donnons plusieurs éléments constructifs et encourageants pour de futures recherches dans la conception d'un bon générateur aléatoire de tressesLIMOGES-BU Sciences (870852109) / SudocSudocFranceF

Contribution aux correspondances entre classifications diagnostiques (dysharmonie psychotique, autres TED et "Multiple complex developmental disorder")

Seule la CFTMEA décrit les dysharmonies psychotiques (DP), qui ont une correspondance systématique avec les autres TED de la CIM-10. Afin d'évaluer la validité de cette correspondance, nous avons reconsidéré le diagnostic de 47 enfants antérieurement diagnostiqués en DP. Notre étude n'a pas permis de valider cette équivalence, puisque seul 1 enfant sur 4 était dans ce cas. La DP semble en revanche recouvrir un éventail de pathologies, particulièrement dans le spectre autistique. Il est toutefois possible de trouver des convergences théoriques entre les DP et les Multiple Complex Developmental Disorders. Le second temps de notre étude, a mis en évidence sur une population ciblée de 25 enfants une correspondance entre MCDD et DP chez 1 enfant sur 2. Cette correspondance s'accroit quand la symptomatologie autistique est moins marquée. Malgré ces nuances sur les correspondances cliniques des DP, l'existence d'un chaînon manquant, entre le spectre autistique et la schizophrénie infantile nous semble pertinente.TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Autism Mental Status Examination (AMSE) (étude préliminaire en population ciblée pour la validation d'un outil de dépistage-diagnostic des troubles du spectre autistique)

TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Tâches et énoncés complexes chez l'enfant : Jugements sémantiques et flexibilité dans le développement typique et le syndrome d'Asperger

International audienc

Socioeconomic Disparities and Prevalence of Autism Spectrum Disorders and Intellectual Disability.

Study of the impact of socioeconomic status on autism spectrum disorders (ASD) and severe intellectual disabilities (ID) has yielded conflicting results. Recent European studies suggested that, unlike reports from the United States, low socioeconomic status is associated with an increased risk of ASD. For intellectual disabilities, the links with socioeconomic status vary according to the severity. We wished to clarify the links between socioeconomic status and the prevalence of ASD (with or without ID) and isolated severe ID.500 children with ASD and 245 children with severe ID (IQ <50) aged 8 years, born 1995 to 2004, were recruited from a French population-based registry. Inclusions were based on clinical diagnoses reported in medical records according to the International Classification of Diseases, 10th Revision. Socioeconomic status was measured by indicators available at block census level which characterize the population of the child's area of residence. Measures of deprivation, employment, occupation, education, immigration and family structure were used. Prevalences were compared between groups of census units defined by the tertiles of socioeconomic level in the general population.Prevalence of ASD with associated ID was higher in areas with the highest level of deprivation and the highest percentage of unemployed adults, persons with no diploma, immigrants and single-parent families. No association was found when using occupational class. Regarding ASD without associated ID, a higher prevalence was found in areas with the highest percentage of immigrants. No association was found for other socioeconomic indicators. The prevalence of isolated severe ID was likely to be higher in the most disadvantaged groups defined by all indicators.The prevalence of ASD with associated ID and of severe isolated ID is more likely to be higher in areas with the highest level of deprivation

Multistage screening process for neurodevelopmental disorders in siblings of children with autism: the FRATSA protocol study

International audienceIntroduction The elevated rates of neurodevelopmental disorders (NDDs) among siblings of children with autism spectrum disorder (ASD) raise concerns about their developmental monitoring and development. The main aim of this study is to assess the feasibility and acceptability of a standardised screening process on a large sample of siblings. Methods and analysis This prospective study will assess the feasibility of a selective and multi-stage screening process for NDD performed on 384 siblings of children with confirmed ASD. Stage 1 will consist of the screening of NDD performed using online parental questionnaires (Social Responsiveness Scale, IdentiDys scale, DCDQ, parental concerns) through a web platform. In cases of a positive result, the second stage, consisting of a clinical semi-structured interview with a psychologist, will be proposed to the sibling before referral for diagnosis and treatment, if necessary. Approximately 12 months after stage 2, parents will be contacted by telephone to collect the diagnosis established following the referrals and their level of satisfaction concerning the screening process. Based on an expected participation rate of 50%, to estimate this rate with an accuracy of 5%, it is necessary to screen 384 subjects. Ethics and dissemination The Ethics Committee on the Research of Human Subjects of Paris (Ile de France VII) approved this study in March 2022 (number: 2021-A02241-40). Express consent is required from all participants. Findings from the cohort study will be disseminated by publication of peer-reviewed manuscripts, presentations at scientific meetings and conferences with associated teams. Trial registration number NCT05512637

Prevalence risk ratios (and their 95% CI bars) of ASD and severe ID by the index of deprivation based on census block groups of residence divided into population quintiles (the first quintile being the least deprived and used as a baseline).

<p>Prevalence risk ratios (and their 95% CI bars) of ASD and severe ID by the index of deprivation based on census block groups of residence divided into population quintiles (the first quintile being the least deprived and used as a baseline).</p

Prevalence of ASD (with and without ID) and severe ID without associated ASD for 1,000 children aged 8 living in the surveillance area and born from 1995 to 2004.

<p>Prevalence of ASD (with and without ID) and severe ID without associated ASD for 1,000 children aged 8 living in the surveillance area and born from 1995 to 2004.</p

Prevalence Risk Ratio of ASD and Severe ID by Six Indicators based on Census Unit Data.

<p>^a n = number of cases in the census unit group defined by tertile of distribution of each indicator in the general population.</p><p>^b PRR = prevalence risk ratio.</p><p>Census units were divided into tertiles according to the distribution of each indicator, the first tertile being the least deprived and used as a baseline for the computing of risk ratios.</p

Prevalence (and 95% confidence interval) for 1,000 children aged 8 and born from 1995 to 2004, by six indicators based on census unit data.

<p>Census units were divided into tertiles of the 8-year-old population according to the distribution of each indicator in the general population. (A) Prevalence of all ASD (B) Prevalence of ASD without intellectual disability (IQ >70). (C) Prevalence of ASD with Intellectual Disability (IQ <70) (D) Prevalence of Severe Intellectual Disability (IQ <50) without ASD.</p