Analyseur de front d'onde d'ordres inférieurs à modulation spatiale

L’imagerie directe pour la détection et l’identification d’exoplanètes apporte un lot de nouveaux défis en instrumentation astronomique. L’utilisation de coronographes à haut contraste nécessite que les aberrations du système optique ainsi que la turbulence atmosphérique soient très bien corrigées afin de supprimer la lumière de l’étoile de façon à pouvoir détecter clairement les objets moins brillants qui pourraient se trouver à proximité de celle-ci. Il devient donc nécessaire d’utiliser des analyseurs de front d’onde spécialisés dans la détection rapide des bas ordres (typiquement les fines erreurs de pointage et de foyer) afin d’atteindre des niveaux de contraste entre l’étoile et une planète de l’ordre de 10Direct imaging aimed at the detection of exoplanets raises new challenges in astronomical instrumentation. The use of high-contrast coronographs to do such tasks requires that the optical system as well as all atmospheric turbulance are corrected near the limit of diffraction in order to remove the light from the adjacent star and detect faint objects that could be near that star. These tight requirements on stability require the use of wavefront sensor specialised in the fast and accurate detection of low-order aberrations (typically pointing and focus errors) to achieve the contrast of 1

FaDIn: Fast Discretized Inference for Hawkes Processes with General Parametric Kernels

Temporal point processes (TPP) are a natural tool for modeling event-based data. Among all TPP models, Hawkes processes have proven to be the most widely used, mainly due to their simplicity and computational ease when considering exponential or non-parametric kernels. Although non-parametric kernels are an option, such models require large datasets. While exponential kernels are more data efficient and relevant for certain applications where events immediately trigger more events, they are ill-suited for applications where latencies need to be estimated, such as in neuroscience. This work aims to offer an efficient solution to TPP inference using general parametric kernels with finite support. The developed solution consists of a fast L2 gradient-based solver leveraging a discretized version of the events. After supporting the use of discretization theoretically, the statistical and computational efficiency of the novel approach is demonstrated through various numerical experiments. Finally, the effectiveness of the method is evaluated by modeling the occurrence of stimuli-induced patterns from brain signals recorded with magnetoencephalography (MEG). Given the use of general parametric kernels, results show that the proposed approach leads to a more plausible estimation of pattern latency compared to the state-of-the-art

Modeling Weather Conditions Consequences on Road Trafficking Behaviors

We provide a model to understand how adverse weather conditions modify traffic flow dynamic. We first prove that the microscopic Free Flow Speed of the vehicles is changed and then provide a rule to model this change. For this, we consider a thresholded linear model, corresponding to an application of a MARS model to road trafficking. This model adapts itself locally to the whole road network and provides accurate unbiased forecasted speed using live or short term forecasted weather data information

Ex vivo multiscale quantitation of skin biomechanics in wild-type and genetically-modified mice using multiphoton microscopy

International audienceSoft connective tissues such as skin, tendon or cornea are made of about 90% of extracellular matrix proteins, fibrillar collagens being the major components. Decreased or aberrant collagen synthesis generally results in defective tissue mechanical properties as the classic form of Elhers-Danlos syndrome (cEDS). This connective tissue disorder is caused by mutations in collagen V genes and is mainly characterized by skin hyperextensibility. To investigate the relationship between the microstructure of normal and diseased skins and their macroscopic mechanical properties, we imaged and quantified the microstructure of dermis of ex vivo murine skin biopsies during uniaxial mechanical assay using multiphoton microscopy. We used two genetically-modified mouse lines for collagen V: a mouse model for cEDS harboring a Col5a2 deletion (a.k.a. pN allele) and the transgenic K14-COL5A1 mice which overexpress the human COL5A1 gene in skin. We showed that in normal skin, the collagen fibers continuously align with stretch, generating the observed increase in mechanical stress. Moreover, dermis from both transgenic lines exhibited altered collagen reorganization upon traction, which could be linked to microstructural modifications. These findings show that our multiscale approach provides new crucial information on the biomechanics of dermis that can be extended to all collagen-rich soft tissues

Cultural flies:Conformist social learning in fruitflies predicts long-lasting mate-choice traditions

Despite theoretical justification for the evolution of animal culture, empirical evidence for it beyond mammals and birds remains scant, and we still know little about the process of cultural inheritance. In this study, we propose a mechanism-driven definition of animal culture and test it in the fruitfly. We found that fruitflies have five cognitive capacities that enable them to transmit mating preferences culturally across generations, potentially fostering persistent traditions (the main marker of culture) in mating preference. A transmission chain experiment validates a model of the emergence of local traditions, indicating that such social transmission may lead initially neutral traits to become adaptive, hence strongly selecting for copying and conformity. Although this situation was suggested decades ago, it previously had little empirical support.</p

Etude de la réorganisation macroscopique de la peau de souris lors d'une sollicitation bi-axiale

La peau est composée en majorité de collagène et présente une microstructure très hiérarchisée qui influe sur son comportement mécanique aux différentes échelles. Pour caractériser l'influence de la microstructure sur les propriétés mécaniques, un test de traction bi-axiale couplé à une mesure macroscopique (corrélation d'images numériques) et microscopique (génération de second harmonique) a été développé . A terme, ce travail permettra de corréler les propriétés macroscopiques à la microstructures. Cette étude présente les résultats de la mesure effectuée par corrélation d'images

Parental educational level and cardiovascular disease risk factors in schoolchildren in large urban areas of Turkey: Directions for public health policy

BACKGROUND: It is widely accepted that the development of atherosclerosis starts at an early age. However, there are very few studies evaluating the prevalence of the common clinical and behavioral cardiovascular disease (CVD) risk factors among children, especially in developing countries. The aim of the present cross-sectional survey was to evaluate the distribution of blood lipid profile and various behavioral (i.e. dietary habits, physical activity status) factors related to CVD risk and its relationships to paternal (PEL) and maternal educational level (MEL) among primary schoolchildren in Turkey. METHODS: In three major metropolises in Turkey (Istanbul, Ankara and Izmir), a random sample of 1044 children aged 12 and 13 years old was examined. ANOVA was applied to evaluate the tested hypothesis, after correcting for multiple comparisons (Tukey correction). RESULTS: After controlling for energy and fat intake, physical activity status and Body Mass Index (BMI), it was found that mostly PEL had a significant positive effect for most of the subgroups examined (Lower vs. Higher and Medium vs. Higher) on TC and HDL-cholesterol and a negative effect on TC/HDL ratio for both genders. Furthermore, both boys and girls with higher PEL and MEL were found to have higher energy intake derived from fat and protein than their counterparts with Medium and Lower PEL and MEL, while the opposite was observed for the percentage of energy derived from carbohydrates. CONCLUSIONS: Our study provides indications for a possible association between an adverse lipid profile, certain dietary patterns and Higher PEL and MEL among schoolchildren in Turkey. These findings underline the possible role of social status, indicated by the degree of education of both parents, in developing certain health behaviors and health indices among Turkish children and provide some guidance for Public Health Policy

Anthropocène : Plan B, création de connaissances pour répondre aux enjeux sociétaux de manière soutenable dans les limites planétaires

De nombreuses recherches et en particulier celles sur les limites planétaires ont montré que nous dépassons actuellement plusieurs limites globales, ce qui questionne fortement la soutenabilité de nos sociétés contemporaines à forte empreinte écologique. Cette prise de conscience se généralise et a fait croître à une vitesse importante les attentes sociétales de visions alternatives à un futur basé sur le seul progrès technologique et/ou une croissance économique infinie.Nous souhaitons faire face à ces constats et aux attentes qu’ils génèrent, sans greenwashing et sans nous en remettre à une croissance verte que nous savons impossible depuis longtemps et notamment par les travaux commandités par le Club de Rome. Impossibilité qui a été rappelée récemment à notre mémoire par une note de l’UE. Pour cela nous souhaitons engager l’UGA dans la construction, sur le long terme, d’une communauté scientifique transdisciplinaire. Nous proposons de développer des recherches complémentaires et alternatives à celles basées sur la double hypothèse d’un éternel progrès technologique et d’une croissance économique qui serait nécessairement vertueuse sur le plan social. Ces recherches auront pour objectif principal d’appréhender la dimension systémique et complexe des questions de dépassement écologique.Pour cela nous savons que nous pouvons d’ores et déjà appuyer notre démarche sur plusieurs collectifs de personnels et d’étudiants nés spontanément dans différentes structures de l’UGA. Leur diversité de profils et de disciplines constitue un atout précieux pour construire une approche transdisciplinaire. Nous pensons donc qu’il est utile et pertinent d’essayer de fédérer ces initiatives dans une démarche collective commune de production de connaissances

rbFOX1/MBNL1 competition for CCUG RNA repeats binding contributes to myotonic dystrophy type 1/type 2 differences

Myotonic dystrophy type 1 and type 2 (DM1, DM2) are caused by expansions of CTG and CCTG repeats, respectively. RNAs containing expanded CUG or CCUG repeats interfere with the metabolism of other RNAs through titration of the Muscleblind-like (MBNL) RNA binding proteins. DM2 follows a more favorable clinical course than DM1, suggesting that specific modifiers may modulate DM severity. Here, we report that the rbFOX1 RNA binding protein binds to expanded CCUG RNA repeats, but not to expanded CUG RNA repeats. Interestingly, rbFOX1 competes with MBNL1 for binding to CCUG expanded repeats and overexpression of rbFOX1 partly releases MBNL1 from sequestration within CCUG RNA foci in DM2 muscle cells. Furthermore, expression of rbFOX1 corrects alternative splicing alterations and rescues muscle atrophy, climbing and flying defects caused by expression of expanded CCUG repeats in a Drosophila model of DM2.Peer reviewe