High resolution climate and vegetation simulations of the Mid-Pliocene, a model-data comparison over western Europe and the Mediterranean region

International audienceHere we perform a detailed comparison between climate model results and climate reconstructions in western Europe and the Mediterranean area for the mid-Piacenzian warm interval (ca 3 Myr ago) of the Late Pliocene epoch. This region is particularly well suited for such a comparison as several quantitative climate estimates from local pollen records are available. They show evidence for temperatures significantly warmer than today over the whole area, mean annual precipitation higher in northwestern Europe and equivalent to modern values in its southwestern part. To improve our comparison, we have performed high resolution simulations of the mid-Piacenzian climate using the LMDz atmospheric general circulation model (AGCM) with a stretched grid which allows a finer resolution over Europe. In a first step, we applied the PRISM2 (Pliocene Research, Interpretation, and Synoptic Mapping) boundary conditions except that we used modern terrestrial vegetation. Second, we simulated the vegetation for this period by forcing the ORCHIDEE (Organizing Carbon and Hydrology in Dynamic Ecosystems) dynamic global vegetation model (DGVM) with the climatic outputs from the AGCM. We then supplied this simulated terrestrial vegetation cover as an additional boundary condition in a second AGCM run. This gives us the opportunity to investigate the model's sensitivity to the simulated vegetation changes in a global warming context

Effect of agent embodiment on the elder user enjoyment of a game

International audienceThis paper presents a study that compared the elder user enjoyment of a game of trivia in three conditions: participants playing the game with a laptop PC vs. a robot vs. a virtual agent. Statistical analysis did not show any significant difference of the three devices on user enjoyment while qualitative analysis revealed a preference for the laptop PC condition, followed by the robot and the virtual agent. The elderly participants were concentrated on the task performance rather on the interaction with systems. They preferred laptop PC condition mainly because there were less interfaces distracting them from performing the task proposed by the game. Further, the robot was preferred to a virtual agent because of its physical presence. Some issues of the experiment design are raised and directions for future research are suggested to gain more insight into the effects of agent embodiment on human-agent interaction

Impact d'un Robot " Majordome " sur l'état psychoaffectif et cognitif de personnes âgées ayant des troubles cognitifs

Les personnes âgées souffrant de troubles cognitifs ont besoin de services, en particulier d'aide sous forme d'entrainement cognitif et de facilitation des contacts sociaux, auxquelles les technologies de l'information et de la communication peuvent répondre. Les équipes (Broca, Valoria, ISIR, Robosoft) du projet TECSAN Robadom (financé par l'ANR) développent et testent auprès de personnes âgées souffrant de troubles cognitifs légers, un robot doté d'émotions et du langage, adapté aux difficultés de ces personnes, contrôlé par elles et qui pourrait contribuer à leur soutien au domicile en apportant différents services tels que des aides matérielles, des relais d'information, un soutien psychologique et cognitif. En début de projet, les scénarii de validations du robot et des spécifications techniques de l'interaction ont été réalisés. La deuxième phase comportait la conception du robot, le développement de la perception multimodale centrée sur l'utilisateur et du modèle émotionnel et cognitif d'interaction. La troisième phase est constituée des évaluations cliniques. Cette tâche permet d'étudier l'acceptabilité, l'utilisabilité et l'impact du robot dans la vie quotidienne (affectif, cognitif, qualité de vie...) et la manière dont le robot est perçu (compagnon, machine, intrus) par les utilisateurs, ainsi que les questions d'éthiques soulevées par le projet à travers une approche transversale prenant en compte aussi bien les dimensions normatives (lois, droits, etc.) que proactives (opinions des usagers)

Dynamics of Non-visual Responses in Humans: As Fast as Lightning?

The eye drives non-visual (NV) responses to light, including circadian resetting, pupillary reflex and alerting effects. Initially thought to depend on melanopsin-expressing retinal ganglion cells (ipRGCs), classical photopigments play a modulatory role in some of these responses. As most studies have investigated only a limited number of NV functions, generally under conditions of relatively high light levels and long duration of exposure, whether NV functions share similar irradiance sensitivities and response dynamics during light exposure is unknown. We addressed this issue using light exposure paradigms spectrally and spatially tuned to target mainly cones or ipRGCs, and by measuring longitudinally (50 min) several NV responses in 28 men. We demonstrate that the response dynamics of NV functions are faster than previously thought. We find that the brain, the heart, and thermoregulation are activated within 1 to 5 min of light exposure. Further, we show that NV functions do not share the same response sensitivities. While the half-maximum response is only ∼48 s for the tonic pupil diameter, it is ∼12 min for EEG gamma activity. Most NV responses seem to be saturated by low light levels, as low as 90 melanopic lux. Our results also reveal that it is possible to maintain optimal visual performance while modulating NV responses. Our findings have real-life implications. On one hand, light therapy paradigms should be re-evaluated with lower intensities and shorter durations, with the potential of improving patients’ compliance. On the other hand, the significant impact of low intensity and short duration light exposures on NV physiology should make us reconsider the potential health consequences of light exposure before bedtime, in particular on sleep and circadian physiology

Le projet Robadom : conception d'un robot d'assistance pour les personnes âgées

National audienceContexte : Le projet ROBADOM a pour objectif de concevoir "un robot majordome", capable de fournirdes interactions verbales et non verbales et des feedbacks pour aider au quotidien les personnes âgées présentant des troubles cognitifs légers. Objectif : Le projet ROBADOM aborde les thématiques suivantes : 1. Le contexte social pour la conception de robots : 1) définir l'apparence du robot et 2) étudier les perceptions et les attitudes des personnes âgées à l'égard d'un robot d'assistance ; 2. Développer les comportements du robot pour créer une interaction "naturelle": 1) des solutions techniques pour un robot expressif, 2) la communication verbale et non verbale entre les personnes âgées et le robot ; 3. Etudier l'acceptabilité du robot chez les personnes âgées ; 4. Etudier l'impact du robot sur les utilisateurs âgés. Méthode : Les quatre études ont impliqué à la fois une méthode qualitative et une méthode expérimentale, réalisées au sein de notre laboratoire "LUSAGE". Résultats et conclusion : Les petits robots avec des traits stylisés ont été appréciés par les participants. Concernant les fonctionnalités, la stimulation cognitive, le rappel de tâches et la localisation d'objets ont été positivement évalués. Bien que les participants jugent le robot utile, ils n'étaient pas encore prêts à l'adopter. De plus, ils ont perçu certaines expressions du robot différemment des personnes jeunes. Ainsi, le système robotisé devra être adapté aux spécificités des personnes âgées. Enfin, nos participants ont soulevé la question de la valeur ajoutée d'un système robotisé par rapport à un ordinateur. Ainsi, de nombreux aspects (technologiques, interaction homme-robot, sociologiques...) restent à explorer avant d'évaluer l'impact du robot d'assistance au domicile

A robust, high-throughput assay to determine the phagocytic activity of clinical antibody samples

Phagocytosis can be induced via the engagement of Fcγ receptors by antibody-opsonized material. Furthermore, the efficiency of antibody-induced effector functions has been shown to be dramatically modulated by changes in antibody glycosylation. Because infection can modulate antibody glycans, which in turn modulate antibody functions, assays capable of determining the induction of effector functions rather than neutralization or titer provide a valuable opportunity to more fully characterize the quality of the adaptive immune response. Here we describe a robust and high-throughput flow cytometric assay to define the phagocytic activity of antigen-specific antibodies from clinical samples. This assay employs a monocytic cell line that expresses numerous Fc receptors: including inhibitory and activating, and high and low affinity receptors—allowing complex phenotypes to be studied. We demonstrate the adaptability of this high-throughput, flow-based assay to measure antigen-specific antibody-mediated phagocytosis against an array of viruses, including influenza, HIV, and dengue. The phagocytosis assay format further allows for simultaneous analysis of cytokine release, as well as determination of the role of specific Fcγ-receptor subtypes, making it a highly useful system for parsing differences in the ability of clinical and vaccine induced antibody samples to recruit this critical effector function.Neutralizing Antibody Consortium (International AIDS Vaccine Initiative)National Institute of Allergy and Infectious Diseases (U.S.)National Institutes of Health (U.S.) (AI055332)National Institutes of Health (U.S.) (AI080289)Ragon Institute of MGH, MIT and Harvar

MHC class I chain-related protein A shedding in chronic HIV-1 infection is associated with profound NK cell dysfunction

Natural killer (NK) cells play a critical role in host defense against viral infections. However chronic HIV-1 infection is associated with an accumulation of dysfunctional NK cells, that poorly control viral replication. The underlying mechanisms for this NK cell mediated dysfunction are not understood. Certain tumors evade NK cell mediated detection by dampening NK cell activity through the downregulation of NKG2D, via the release of soluble NKG2D-ligands, resulting in a potent suppression of NK cell function. Here we show that chronic HIV-1 infection is associated with a specific defect in NKG2D-mediated NK cell activation, due to reduced expression and transcription of NKG2D. Reduced NKG2D expression was associated with elevated levels of the soluble form of the NKG2D-ligand, MICA, in patient sera, likely released by HIV+CD4+ T cells. Thus, like tumors, HIV-1 may indirectly suppress NK cell recognition of HIV-1-infected CD4+ T cells by enhancing NKG2D-ligand secretion into the serum resulting in a profound impairment of NK cell function

A new model for fatty acid hydroxylase-associated neurodegeneration reveals mitochondrial and autophagy abnormalities

Fatty acid hydroxylase-associated neurodegeneration (FAHN) is a rare disease that exhibits brain modifications and motor dysfunctions in early childhood. The condition is caused by a homozygous or compound heterozygous mutation in fatty acid 2 hydroxylase (FA2H), whose encoded protein synthesizes 2-hydroxysphingolipids and 2-hydroxyglycosphingolipids and is therefore involved in sphingolipid metabolism. A few FAHN model organisms have already been established and give the first insight into symptomatic effects. However, they fail to establish the underlying cellular mechanism of FAHN so far. Drosophila is an excellent model for many neurodegenerative disorders; hence, here, we have characterized and validated the first FAHN Drosophila model. The investigation of loss of dfa2h lines revealed behavioral abnormalities, including motor impairment and flying disability, in addition to a shortened lifespan. Furthermore, alterations in mitochondrial dynamics, and autophagy were identified. Analyses of patient-derived fibroblasts, and rescue experiments with human FA2H, indicated that these defects are evolutionarily conserved. We thus present a FAHN Drosophila model organism that provides new insights into the cellular mechanism of FAHN