"I know that you know that I know": neural substrates associated with social cognition deficits in DM1 patients

Myotonic dystrophy type-1 (DM1) is a genetic multi-systemic disorder involving several organs including the brain. Despite the heterogeneity of this condition, some patients with non-congenital DM1 can present with minimal cognitive impairment on formal testing but with severe difficulties in daily-living activities including social interactions. One explanation for this paradoxical mismatch can be found in patients' dysfunctional social cognition, which can be assessed in the framework of the Theory of Mind (ToM). We hypothesize here that specific disease driven abnormalities in DM1 brains may result in ToM impairments. We recruited 20 DM1 patients who underwent the "Reading the Mind in the Eyes" and the ToM-story tests. These patients, together with 18 healthy controls, also underwent resting-state functional MRI. A composite Theory of Mind score was computed for all recruited patients and correlated with their brain functional connectivity. This analysis provided the patients' "Theory of Mind-network", which was compared, for its topological properties, with that of healthy controls. We found that DM1 patients showed deficits in both tests assessing ToM. These deficits were associated with specific patterns of abnormal connectivity between the left inferior temporal and fronto-cerebellar nodes in DM1 brains. The results confirm the previous suggestions of ToM dysfunctions in patients with DM1 and support the hypothesis that difficulties in social interactions and personal relationships are a direct consequence of brain abnormalities, and not a reaction symptom. This is relevant not only for a better pathophysiological comprehension of DM1, but also for non-pharmacological interventions to improve clinical aspects and impact on patients' success in life

Evaluation d'un modèle du devenir d'herbicides en parcelle drainée, développé à l'aide d'une plate-forme de modélisation environnementale

Dans le contexte de la modélisation de la pollution par les produits phytosanitaires en milieu rural, on présente un modèle local de devenir de solutés en parcelle artificiellement drainée, appelé SI#. Il simule la hauteur de nappe à l'interdrain, les débits drainé et ruisselé, ainsi que les concentrations en produits phytosanitaires dans les eaux de drainage et de ruissellement, pour des événements pluvieux correspondant à la saison de drainage intense dans le contexte pédo-climatique du Grand Ouest de la France. Le support pour son implémentation et application est la plate-forme de modélisation intégrée LIQUID®. SI# est testé par comparaison avec des données expérimentales issues du site Arvalis de La Jaillière (44), pour les produits Isoproturon et Diflufénicanil, aux échelles de l'événement pluvieux et de la saison de drainage intense. Les résultats montrent un bon comportement global de SI#, en termes de débits et de concentrations

Impact cumulé des petites retenues : une revue des évaluations et méthodes

International audienceDue to a reduce cost, availability of many favorablefavourable locations, easy access due to proximity, the number of small reservoirs has increased. The cumulative impact of reservoirs in a catchment is considered as the modifications induced by the reservoir network taken as a whole. The impact may exert on the flow regimes and sediment, nutrient and contaminant transfer, and thereby modify the ecological behaviour of the aquatic environment, the continuity of rivers and the habitats of organisms living in them. The cumulative impact is not necessarily the sum of individual and local modifications, because reservoirs may be inter-dependent. This is the case for instance in cascading reservoirs along a stream course. The cumulative impact is not straightforward to estimate, even solely considering hydrological impact, in part due to the difficulty to collect data on the functioning of those reservoirs. However, there are evidences that the cumulative impacts are not negligible. This work is dedicated to a review of the studies dealing with the cumulative impact of small reservoirs on hydrology, focusing on the methodology as well as on the way the impacts are reported. It is shown that similar densities of small reservoirs can lead to different impacts on the quantitative water resource in different regions. This is probably due to the hydro-climatic conditions, and makes it difficult to define simple indicators to provide a first guess of the cumulative impact. The impacts vary also on time, with a more intense reduction of the river discharge during the dry years than during the wet years. This is certainly an important point to take into account in a context of climate change

Aide à l’optimisation des actions de protection des captages. Méthodologie de choix d’actions pertinentes en fonction des typologies de transfert sur une Aire d’Alimentation de Captage. Application aux captages Grenelle. Irstea - BRGM - ONEMA

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAUCe projet vise à élaborer des outils et méthodes pour définir des programmes d’action adaptés sur des aires d’alimentation de captages. Le travail a permis d’élaborer une typologie théorique des captages en termes de modes d’écoulements dominant, de choisir quelques captages représentatifs de chaque classe de la typologie élaborée et d’amorcer, pour quelques uns de ces captages, un diagnostic adapté au type de captage considéré, en s’appuyant le cas échéant sur le diagnostic déjà effectué et en étudiant la faisabilité d’optimiser le diagnostic en s’appuyant sur les données de contamination disponibles (pesticides, métabolites, nutriments…)

Utilisation de la plate-forme LIQUID pour modéliser l'influence d'aménagements hydro-agricoles sur l'hydrologie d'un petit bassin versant

Sur les petits bassins versants ruraux, la question du fonctionnement hydrologique est intimement liée à la façon dont ces bassins sont aménagés. Le façonnage du paysage par la présence humaine et l'activité agricole (découpage de parcellaire, drainage de certaines parcelles, plantation de haies en bord de parcelles, creusement de fossés) peut modifier profondément les processus hydrologiques, et avoir des conséquences importantes, notamment en termes de pollutions diffuses d'origine agricole (nutriments ou produits phytosanitaires). Si l'on veut répondre à des questions d'aménagement de ces bassins pour par exemple limiter les pollutions, on a besoin de modélisations hydrologiques précises, représentant explicitement les différents éléments du paysage susceptibles d'avoir un effet hydrologique important, y compris dans leurs formes géométriques et leurs positionnements dans l'espace

Modélisation du transport de solutés dans une parcelle agricole drainée à l'aide de compartiments équivalents

Subsurface drainage is a widely spread agricultural management device that deeply influences water path and solute transport. Indeed it generates 2D water flows (vertical in unsaturated zone, radial close to the pipe, horizontal in saturated zone at mid drain spacing). As a consequence solute transport is spatially and temporally heterogeneous. Elution curves usually present a typical pattern with a fast peak and long tail. A dedicated modelling tool was developed from this background. As a coupled Boussinesq/reservoir simplified model is already available for hydrodynamics representation, a conceptual approach is preferred for solute transport. The soil equivalent compartments approach is based on observation of water flow paths in a 2D drained soil profile and the estimation of travel times of solute particles from soil surface to the drain for different hydrodynamical conditions. Then the soil can be divided into several compartments with quite homogeneous travel times. Solute transport is represented in each compartment using an exponential transfer function parametrized by drain flow and travel time. Adsorption and degradation coefficients for reactive solutes are also added. Such a solute transport model was implemented and tested against field data for herbicide Isoproturon. First results are encouraging : after calibration, fast breakthroughs after rainfall events are reproduced correctly and simulated pesticide concentrations in drain flow are quite accurate

Du bassin agricole aux scénarios d'aménagement: un outil modulaire pour évaluer l'effet des éléments du paysage sur le devenir de l'eau et des pesticides

International audiencePesticide transfers and fate are highly influenced by the presence of discontinuities such as grass strips, slopes, hedgerows or roads that can accelerate or slow down and dissipate water and contaminant fluxes. That is why those landscape elements must be integrated into watershed management plans. It implies taking them into account when modeling water and contaminant fluxes at the small catchment scale. However, if the influence of landscape elements has already been widely explored at field scale, models generally do not reach the catchment scale. The project PESHMELBA aims at developing a new modeling tool of water and contaminants circulation and fate at the scale of small catchments in order to optimize landscape organization. The model explicitly takes into account spatial organization of landscape by representing existing elements, their locations and shapes. The final aim of this modeling tool is to efficiently test and rank different development scenarios in order to assess the influence of agricultural practices, land uses and landscape management strategies on water quality. In PESHMELBA, dominating processes ruling water and contaminants circulation and dissipation for each element type are mainly represented by existing and validated models. New components have also been developed when no suitable model was found in the literature. All these models present different levels of conceptualization and are used as modeling units ensuring a modular structure. Then, the different units are gathered and connected in the OpenPALM coupler (Fouilloux and Piacentini, 1999) in order to implement the spatial and temporal couplings. This innovative approach leads to a spatialized model of the whole catchment. Applications cases are tested with an increasing complexity, from a case with two plots to the hillslope scale with several plots, ditches and rivers. They show that PESHMELBA is a promising tool to compare scenarios considering water and pesticide fate in different complex landscapes