Unsupervised Manifold Learning using High-order Morphological Brain Networks derived from T1-w MRI for Autism Diagnosis

Brain disorders, such as Autism Spectrum Disorder (ASD), alter brain functional (from fMRI) and structural (from diffusion MRI) connectivities at multiple levels and in varying degrees. While unraveling such alterations have been the focus of a large number of studies, morphological brain connectivity has been out of the research scope. In particular, shape-to-shape relationships across brain regions of interest (ROIs) were rarely investigated. As such, the use of networks based on morphological brain data in neurological disorder diagnosis, while leveraging the advent of machine learning, could complement our knowledge on brain wiring alterations in unprecedented ways. In this paper, we use conventional T1-weighted MRI to define morphological brain networks (MBNs), each quantifying shape relationship between different cortical regions for a specific cortical attribute at both low-order and high-order levels. While typical brain connectomes investigate the relationship between two ROIs, we propose high-order MBN which better captures brain complex interactions by modeling the morphological relationship between pairs of ROIs. For ASD identification, we present a connectomic manifold learning framework, which learns multiple kernels to estimate a similarity measure between ASD and normal controls (NC) connectional features, to perform dimensionality reduction for clustering ASD and NC subjects. We benchmark our ASD identification method against both supervised and unsupervised state-of-the-art methods, while depicting the most discriminative high- and low-order relationships between morphological regions in the left and right hemispheres

Modélisation tribo-physique de la coupe des composites FRP : Approches numérique et expérimentale

Since several decades, the material removal process of Fiber Reinforced Polymers (FRP) continues to raise technical and scientific queries. The understanding of the multiple and complex phenomena generated when cutting still remains challenging for controlling the behavior of composite structures. This study addresses a multiscale analysis of elementary phenomena associated to each of the composite constituents in order to model the chip formation mechanisms owing to the multiphysical coupling. An investigation combining the experimental approach resulting in the instrumented test and numerical approach allowing to the finite element (FE) development was hence conducted. A VUMAT subroutine was built to express the constitutive formulation coupling the continuum damage mechanics to the failure mechanics by means of the triptych elasticity-damage-failure. Unlike to the binary approaches proposed by the open literature, the model proposed herein bases on the progressive damage concept for predicting the physical failure allowing to the formation of the chip. The crack initiation and growth mechanisms are controlled by the failure energies determined experimentally for each material phase. The efficiency of the VFRIC subroutine to managing the contact properties, i.e. friction, at the tool-material interface was confirmed. The numerical results proved the reliability of the model to simulate the chip formation mechanisms with respect of fiber orientation. The good agreement between the measured and predicted forces proved the interest of the rigorous modeling of the tool-material interface.Depuis des décennies, le processus d'enlèvement de matière des composites à matrices polymères (CMP) ne cesse de susciter des interrogations. La complexité et la multitude des phénomènes physiques activés par la coupe constituent encore un défi d'actualité pour la compréhension et la maitrise du comportement des structures composites. Ce travail propose une analyse multiéchelle fine des phénomènes élémentaires émanant du comportement de chacune des phases constituantes du matériau afin de modéliser leurs couplages multiphysiques potentiels conduisant à la formation du copeau. L'étude est alors hybride conjuguant l'approche expérimentale exprimée par l'essai instrumenté et l'approche numérique exprimée par la modélisation par éléments finis (EF). La formulation du couplage multiphysique a fait l'objet d'une routine VUMAT alliant la mécanique de l'endommagement continu à la mécanique de la rupture par le biais du triptyque élasticité-endommagement-rupture. A la différence des approches binaires de la littérature, le modèle développé dans ce travail s'appuie sur un concept d'endommagement progressif pour prédire la rupture physique des phases, et par conséquent, la formation du copeau. Les mécanismes d'initiation et de propagation de la fissure sont pilotés par les énergies de rupture des phases identifiées selon les normes en vigueur. La gestion du contact par une routine VFRIC a permis d'assurer la synergie entre les propriétés locales de l'interface et les frottements générés. Les calculs ont démontré la pertinence du modèle tridimensionnel proposé dans la simulation des mécanismes de formation du copeau sensiblement à l'orientation et la nature des fibres. La bonne concordance entre les mesures et les prédictions d'efforts de coupe a mis en évidence l'intérêt d'un pilotage rigoureux du contact outil-pièce pour la simulation multiphysique de la coupe

An in-depth methodology to predict at-risk learners

International audienceNowadays, the concept of education for all is gaining momentum thanks to the widespread use of e-learning systems around the world. The use of e-learning systems consists in providing learning content via the Internet to physically dispersed learners. The main challenge in this regard is the high fail rate particularly among k-12 learners who are our case study. Therefore, we established an in-depth methodology based on machine learning models whose objectives are the early prediction of at-risk learners and the diagnosis of learning problems. Going through this methodology was of a great importance thus it started by identifying the most relevant learning indicators among performance, engagement, regularity and reactivity. This, then, led us to extract and select the adequate learning features that reflect the activity of an online learner. For the modeling part of this methodology, we apply machine learning models among k-nearest neighbors (K-nn), Support Vector Machine (SVM), Random Forest and Decision tree on a real data sample of 1361 k-12 learners. The evaluation step consists in comparing the ability of each model to correctly identify the class of learners at-risk of failure using both accuracy and False Positive Rate (FPR) measures

Multi-view Brain Network Prediction from a Source View Using Sample Selection via CCA-Based Multi-kernel Connectomic Manifold Learning

Several challenges emerged from the dataclysm of neuroimaging datasets spanning both healthy and disordered brain spectrum. In particular, samples with missing data views (e.g., functional imaging modality) constitute a hurdle to conventional big data learning techniques which ideally would be trained using a maximum number of samples across all views. Existing works on predicting target data views from a source data view mainly used brain images such as predicting PET image from MRI image. However, to the best of our knowledge, predicting a set of target brain networks from a source network remains unexplored. To ll this gap, a multi-kernel manifold learning (MKML) framework is proposed to learn how to predict multi-view brain networks from a source network to impute missing views in a connectomic dataset. Prior to performing multiple kernel learning of multi-view data, it is typically assumed that the source and target data come from the same distribution. However, multi-view connectomic data can be drawn from different distributions. In order to build robust predictors for predicting target multi-view networks from a source network view, it is necessary to take into account the shift between the source and target domains. Hence, we first estimate a mapping function that transforms the source and the target domains into a shared space where their correlation is maximized using canonical correlation analysis (CCA). Next, we nest the projected training and testing source samples into a connectomic manifold using multiple kernel learning, where we identify the most similar training samples to the testing source network. Given a testing subject, we introduce a cross-domain trust score to assess the reliability of each selected training sample for the target prediction task. Our model outperformed both conventional MKML technique and the proposed CCA-based MKMLtechnique without enhancement by trust scores

Prévalence et facteurs associés aux grossesses en milieu scolaire au Bénin en 2021

Girls' education, recognized as an essential pillar of sustainable development, is sometimes handicapped by the phenomenon of pregnancy in schools. The. The objective of our study is to study the prevalence and factors associated with school pregnancy in Benin in 2021. This was a cross-sectional survey conducted in 2021 and involved girls who benefited from Benin's Sexual Health Education (SHE) project. They were selected using a probabilistic method. Explanatory variables included sociodemographic, behavioral, and reproductive history characteristics. A logistic regression model was used to identify factors associated with school pregnancy. The significance level was 5%. The study included 3652 girls. The mean age was 17.47 ± 2.35 years with extremes of 11 and 24 years. The prevalence of school pregnancy was 5.61% among all girls surveyed and 15.99% among sexually active girls. Factors associated with school-based pregnancy included age ≥20 years; (OR=3.79; CI95%: 2.56-5.62) ,belonging to the collines (OR=2.78; CI95% 1.10-7.02) and atlantique departments (OR=2.83; CI95% 1.13-7.10), not living with both parents (OR=0.57; CI95% 0.38-0.86), frequent prostitution (OR=3.10; CI95% 1.31-7.33) or sometimes (OR = 2.61; CI95% 1.13-6.00), poor or insufficient parental control (OR = 2.42; CI95% 1.58-3.69), and low socioeconomic level of the home household (OR = 1.75; CI95% 1.02-3.01). The phenomenon of pregnancy in schools in Benin is a reality. This study provides evidence to decision-makers at different levels for an efficient fight.   L'éducation des filles, reconnue comme un pilier essentiel du développement durable, est parfois handicapée par  le phénomène de grossesse en milieu scolaire. Dans le but de contribuer à contrôler le phénomène, l’objectif de notre étude est d’étudier la prévalence et les facteurs associés aux grossesses en milieu scolaire au Bénin en 2021. Il s’est agi d’une  enquête transversale réalisée en 2021 et qui a concerné les élèves filles ayant bénéficié du projet Education à la Santé Sexuelle (ESS) au Bénin. Elles étaient sélectionnées selon une méthode probabiliste. Les variables explicatives comprenaient les caractéristiques sociodémographiques, comportementaux et l’histoire reproductive. Un modèle de régression logistique a été utilisé pour identifier les facteurs associés aux besoins non satisfaits. Le seuil de significativité était de 5%. L’étude a inclus  3652 filles. La moyenne d’âge était de 17,47 ± 2,35 ans avec les extrêmes 11 ans et de 24 ans. La prévalence des grossesses en milieu scolaire était de 5,61% chez l’ensemble des filles enquêtées et de 15,99% chez les filles sexuellement actives. Les facteurs associés au phénomène comprenaient l’âge ≥20 ans ; (OR=3,79 ; IC95% : 2,56-5,62), l’appartenance aux départements des collines (OR = 2,78 ; IC95%  1,10-7,02) et de l’atlantique (OR = 2,83 ; IC95%  1,13-7,10), le fait ne pas vivre avec les deux parents (OR = 0,57 ; IC95%  0,38-0,86), se prostituer souvent (OR = 3,10 ; IC95%  1,31-7,33) ou parfois (OR = 2,61 ; IC95%  1,13-6,00), le faible ou insuffisance de contrôle parental (OR = 2,42 ; IC95%  1,58-3,69) et le faible niveau socioéconomique du ménage d’appartenance (OR = 1,75 ; IC95%  1,02-3,01).  Le phénomène de grossesse en milieu scolaire au Bénin est une réalité. La présente étude met à disposition des décideurs à différents niveaux des évidences pour une lutte efficiente.  &nbsp

Prévalence et facteurs associés aux grossesses en milieu scolaire au Bénin en 2021

Girls' education, recognized as an essential pillar of sustainable development, is sometimes handicapped by the phenomenon of pregnancy in schools. The. The objective of our study is to study the prevalence and factors associated with school pregnancy in Benin in 2021. This was a cross-sectional survey conducted in 2021 and involved girls who benefited from Benin's Sexual Health Education (SHE) project. They were selected using a probabilistic method. Explanatory variables included sociodemographic, behavioral, and reproductive history characteristics. A logistic regression model was used to identify factors associated with school pregnancy. The significance level was 5%. The study included 3652 girls. The mean age was 17.47 ± 2.35 years with extremes of 11 and 24 years. The prevalence of school pregnancy was 5.61% among all girls surveyed and 15.99% among sexually active girls. Factors associated with school-based pregnancy included age ≥20 years; (OR=3.79; CI95%: 2.56-5.62) ,belonging to the collines (OR=2.78; CI95% 1.10-7.02) and atlantique departments (OR=2.83; CI95% 1.13-7.10), not living with both parents (OR=0.57; CI95% 0.38-0.86), frequent prostitution (OR=3.10; CI95% 1.31-7.33) or sometimes (OR = 2.61; CI95% 1.13-6.00), poor or insufficient parental control (OR = 2.42; CI95% 1.58-3.69), and low socioeconomic level of the home household (OR = 1.75; CI95% 1.02-3.01). The phenomenon of pregnancy in schools in Benin is a reality. This study provides evidence to decision-makers at different levels for an efficient fight.   L'éducation des filles, reconnue comme un pilier essentiel du développement durable, est parfois handicapée par  le phénomène de grossesse en milieu scolaire. Dans le but de contribuer à contrôler le phénomène, l’objectif de notre étude est d’étudier la prévalence et les facteurs associés aux grossesses en milieu scolaire au Bénin en 2021. Il s’est agi d’une  enquête transversale réalisée en 2021 et qui a concerné les élèves filles ayant bénéficié du projet Education à la Santé Sexuelle (ESS) au Bénin. Elles étaient sélectionnées selon une méthode probabiliste. Les variables explicatives comprenaient les caractéristiques sociodémographiques, comportementaux et l’histoire reproductive. Un modèle de régression logistique a été utilisé pour identifier les facteurs associés aux besoins non satisfaits. Le seuil de significativité était de 5%. L’étude a inclus  3652 filles. La moyenne d’âge était de 17,47 ± 2,35 ans avec les extrêmes 11 ans et de 24 ans. La prévalence des grossesses en milieu scolaire était de 5,61% chez l’ensemble des filles enquêtées et de 15,99% chez les filles sexuellement actives. Les facteurs associés au phénomène comprenaient l’âge ≥20 ans ; (OR=3,79 ; IC95% : 2,56-5,62), l’appartenance aux départements des collines (OR = 2,78 ; IC95%  1,10-7,02) et de l’atlantique (OR = 2,83 ; IC95%  1,13-7,10), le fait ne pas vivre avec les deux parents (OR = 0,57 ; IC95%  0,38-0,86), se prostituer souvent (OR = 3,10 ; IC95%  1,31-7,33) ou parfois (OR = 2,61 ; IC95%  1,13-6,00), le faible ou insuffisance de contrôle parental (OR = 2,42 ; IC95%  1,58-3,69) et le faible niveau socioéconomique du ménage d’appartenance (OR = 1,75 ; IC95%  1,02-3,01).  Le phénomène de grossesse en milieu scolaire au Bénin est une réalité. La présente étude met à disposition des décideurs à différents niveaux des évidences pour une lutte efficiente.  &nbsp

Recombinant tandem of pore-domains in a Weakly Inward rectifying K+ channel 2 (TWIK2) forms active lysosomal channels

Recombinant TWIK2 channels produce weak basal background K+ currents. Current amplitudes depend on the animal species the channels have been isolated from and on the heterologous system used for their re-expression. Here we show that this variability is due to a unique cellular trafficking. We identified three different sequence signals responsible for the preferential expression of TWIK2 in the Lamp1-positive lysosomal compartment. Sequential inactivation of tyrosine-based (Y(308)ASIP) and di-leucine-like (E266LILL and D(282)EDDQVDIL) trafficking motifs progressively abolishes the targeting of TWIK2 to lysosomes, and promotes its functional relocation at the plasma membrane. In addition, TWIK2 contains two N-glycosylation sites (N(79)AS and N(85)AS) on its luminal side, and glycosylation is necessary for expression in lysosomes. As shown by electrophysiology and electron microscopy, TWIK2 produces functional background K+ currents in the endolysosomes, and its expression affects the number and mean size of the lysosomes. These results show that TWIK2 is expressed in lysosomes, further expanding the registry of ion channels expressed in these organelles

Développement de la pratique infirmière avancée dans le système de santé du Bénin : une exploration contextuelle inspirée de l’Ethnonursing de Leininger et guidée par le modèle PEPPA

Introduction: The reform of the training system in Nursing and Midwifery Sciences (NMS) in Benin made it possible to train nurses at the academic master's level in the Advanced Practice Nurse (APN) profile. However, despite the recognition of this new training on an academic level, the role of the APN in the health system where these nurses will be called upon to practice in a multidisciplinary team at the heart of a very diversified medical and nursing culture and practices, is not yet clarified.   Objectives: 1- Identify the areas of intervention, scope of action, roles, mandates and possible activities of the APN, as well as the factors favorable and unfavorable to the development of Advanced Nursing Practice (ANP) in the Benin health system; 2- Determine the constituent elements of a formal and regulatory framework for the exercise of ANP in Benin. Methods: This qualitative research based on Leininger's theory of universality and diversity of care (1991) will also be based on the PEPPA model (Participatory, Evidence-Based, Patient-Focused Process for Advanced Practice Nursing) proposed by Bryant-Lukosius and Dicenso (2004) for sequencing the stages of development, implementation and evaluation of a new APN role. Semi-directed individual interviews and focused groups with nurses and midwives of Beninese nationality holding a master's degree in NMS will be conducted. Self-administered questionnaires and collection of texts will be used to collect data from health personnel and managers of clinical care structures and services. Discussion and Research Spin-offs: This study will identify the benchmarks that will support the implementation of the APN role in Benin's health system, clarifying its areas of intervention, scope of action, mandates and possible activities, as well as the context necessary for its implementation.Introduction : La réforme du système de formation en sciences infirmières et obstétricales (SIO) au Bénin a permis de former des infirmiers de niveau maitrise académique dans le profil infirmière en pratique avancée (IPA). Cependant, malgré la reconnaissance de cette nouvelle formation sur le plan académique, le rôle de l’IPA dans le système de santé où ces infirmiers sont appelés à exercer dans une équipe multidisciplinaire au cœur d’une culture et de pratiques médicales et infirmières très diversifiées n’est pas encore clarifié. Objectifs : 1- Identifier les domaines d’intervention, les périmètres d’action, les rôles, les mandats et les activités possibles de l’IPA, ainsi que les facteurs favorables et défavorables au développement de la pratique infirmière avancée (PIA) dans le système de santé du Bénin; 2- Déterminer les éléments constitutifs d’un cadre formel et réglementaire d’exercice de la PIA au Bénin. Méthodes : Cette recherche qualitative basée sur la théorie de l’universalité et de la diversité des soins de Leininger (1991) s’appuiera sur le modèle PEPPA (Participatory, Evidence-Based, Patient-Focused Process for Advanced Practice Nursing) proposé par Bryant-Lukosius et Dicenso (2004) pour la séquence des étapes de développement, d’implantation et d’évaluation d’un nouveau rôle d’IPA. Des entrevues individuelles semi-dirigées et groupes focalisés auprès des infirmiers et sages-femmes de nationalité béninoise titulaires d’une maitrise en SIO seront réalisés. Des questionnaires auto-administrés et un recueil de textes permettront de collecter des données auprès du personnel de santé et des responsables des structures et services de soins cliniques. Discussion et retombées anticipées : Cette étude permettra d’identifier les balises qui soutiendront l’implantation du rôle de l’IPA dans le système de santé du Bénin, clarifiant ses domaines d’intervention, ses périmètres d’action, ses mandats et activités possibles, ainsi que le contexte nécessaire pour son implantation

Antagonistic Effect of a Cytoplasmic Domain on the Basal Activity of Polymodal Potassium Channels

TREK/TRAAK channels are polymodal K+ channels that convert very diverse stimuli, including bioactive lipids, mechanical stretch and temperature, into electrical signals. The nature of the structural changes that regulate their activity remains an open question. Here, we show that a cytoplasmic domain (the proximal C-ter domain, pCt) exerts antagonistic effects in TREK1 and TRAAK. In basal conditions, pCt favors activity in TREK1 whereas it impairs TRAAK activity. Using the conformation-dependent binding of fluoxetine, we show that TREK1 and TRAAK conformations at rest are different, and under the influence of pCt. Finally, we show that depleting PIP2 in live cells has a more pronounced inhibitory effect on TREK1 than on TRAAK. This differential regulation of TREK1 and TRAAK is related to a previously unrecognized PIP2-binding site (R329, R330, and R331) present within TREK1 pCt, but not in TRAAK pCt. Collectively, these new data point out pCt as a major regulatory domain of these channels and suggest that the binding of PIP2 to the pCt of TREK1 results in the stabilization of the conductive conformation in basal conditions