Scientific Publications of the University of Toulouse II Le Mirail
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Cortical processing for the vestibular and visual input of egomotion in macaque monkeys: Separate networks with targeted convergence
No full textInternational audienceThe integration of visual and vestibular inputs during egomotion is fundamental for both postural and navigational control. In the present study, we used functional magnetic resonance imaging (fMRI) in four macaque monkeys to investigate cortical activation in response to galvanic vestibular stimulation (GVS), applied through transmastoid electrodes, and egomotion-compatible (EC) optic flow patterns. Visual and vestibular stimulations activate two largely independent cortical networks: the vestibular network encompasses the insular cortex, superior parietal lobule, frontal lobe, and cingulate cortex, while optic flow primarily activates regions in the superior temporal sulcus, temporo-parietal junction, inferior parietal lobule, and restricted portions of the cingulate and frontal cortices. Despite this segregation, several areas exhibit visuo-vestibular convergence: ventral posterior suprasylvian (VPS) in the temporo-parietal junction, area 7 in the inferior parietal lobule, ventral intraparietal area (VIP) and LIP in the intraparietal sulcus, MSTd in the superior temporal sulcus, CSv in the cingulate sulcus, and FEFsem in the frontal cortex. These findings demonstrate that visual and vestibular signals generated by egomotion are processed in extended and distinct cortical networks with several narrow convergence sites, consistent with the idea that multisensory integration during self-motion is achieved through selective convergence rather than general network overlap
Images that Highlight: The Case of Video Calls Between an Emergency Call Service and People with Aphasia
No full textInternational audienceThis study is part of a wider project to ensure that people with aphasia have better access to emergency calls in France, via Centre National Relais 114 (CNR114), a specialized emergency call reception center. We collected data from video calls between 114’s agents and aphasic volunteers simulating emergency situations. We closely examined how participants deal with comprehension problems, in particular how the agent's use of images shown and pointed at the camera proves decisive. Using a conversation analysis approach that takes into account the specificity of the participants, we provide emblematic cases of what we found in the data, all in line with the practical problem of organizing and ensuring mutual understanding, through referential activities. The results reveal some in-depth aspects of emergency service agents’ expertise from an interactional and creative point of view: facilitating the progressivity of interaction and ensuring a better understanding of the different referents mobilized in discourse
Temporal evolution and origin of radionuclide fallout and contaminants recorded in sediment from the Kerguelen Archipelago fjord system
No full textInternational audienceDeposition of heavy metals and persistent organic pollutants (POPs) to fjord systems during ice melting was investigated with a sediment core collected in Table Fjord from Kerguelen Island (49° 33.8 S-69° 13.9 E) situated in the Southern Indian Ocean. Multiple radionuclides ( 210 Pbex, 137 Cs, 240 Pu/ 239 Pu) were used to establish an accurate age-depth model and show the occurrence of French nuclear weapon test fallout in this remote region for the first time. Environmental changes related to the retreat of the Cook Ice Cap since the 1960s were found to be one of the major factors dominating the dynamics of anthropogenic lead deposition flux in the fjord through the release of long-range transported legacy anthropogenic lead. The released legacy anthropogenic lead was likely transported across the proglacial Ampere Lake by a hypopycnal plume to the fjord. Backward trajectories and lead stable isotopic signatures suggest the southern part of South Africa as a major source of anthropogenic lead transported to Kerguelen Archipelago. In contrast, contamination by arsenic, molybdenum, antimony and POPs was found to be more recent (since 2001). Fractionation of rare earth elements was observed in the sediment due to the formation of proglacial Ampere Lake, which acts as a sediment trap
Simulation numérique directe de la combustion d'une particule d'aluminium isolée sous divers environnements
No full textThe authors acknowledge the French Defense Agency for funding L.P.’s scholarship and CALMIP supercomputing centre in Toulouse (France) for providing us computational resources.International audienceThis study presents a comprehensive numerical investigation of single aluminum particle combustion under varying convective oxidizing flow conditions, using Direct Numerical Simulations. A three-dimensional, boundary-layer-resolved model is developed to capture the complex interplay of gas-phase chemistry, surface reactions, and multiphase transport phenomena. The model incorporates aluminum evaporation, aluminum suboxide reactions at the particle's surface, and alumina formation both on the surface and in the gas phase. It also introduces an original scheme to account for the dissolution of alumina into the molten particle, based on parameters derived from molecular dynamics simulations. The model was validated against experimental burn time data. The unsteady combustion of a 125 μm-aluminum particle in various flowing O2/N2 conditions is then investigated in terms of standoff flame distance, gas-phase temperature and chemistry, particle temperature and surface chemistry. The results demonstrate that gas-phase reactions remain the dominant source of heat release, although surface reactions, particularly under highly oxygenated environments, play a significant role in modulating local combustion kinetics. The formation of liquid alumina at the particle's surface, its partial dissolution into the molten aluminum, and the limited surface coverage even at high O2 concentrations highlight the importance of coupling surface chemistry with thermal transport. While this mathematical model successfully reproduces the main macroscopic characteristics such as flame temperature, burn time-radius relationship, gas-phase composition, and fluxes, some discrepancies appear near the particle surface, i.e. at the microscale. These deviations can be attributed to radiative heat transfer effects which are not considered or to an incomplete understanding of surface reactions
High alpine preglacial caves modified by glacial processes and late condensationcorrosion in the Scerscen Valley (Valmalenco, Western Alps, Italy)
No full textInternational audienceThe Scerscen Valley (western Italian Alps) is home to caves at an altitude of around 2600 m, opening close to the Speleogenesis edge of a glacier. The aim of the research as part of a multi-disciplinary project was to reconstruct the evolution Alpine Cosmogenic GeomorphologyHydrogeologyglaciersburial dating of cosmonucleide some the of caves the related most burial recent to dating, the processes, geological recorded such and morphology paleoenvironmental as condensation-corrosion and micrometeorology, evolution and of sediment the carried area deposition. and out mineralogical to evaluate We the performed identifirole of cation by XRD, and hydrogeology using dye tracing and physical and chemical analyses. The cosmonucleide dating of quartz pebbles showed that the Veronica Cave is the oldest, with deposits dated at 1.3 ± 0.4 Ma, and possibly even older. It certainly formed at a much lower altitude (approx. 1300 m a.s.l. or lower) during the Alpine uplift. The Morgana and Marsooi caves, given the smaller volume of their phreatic conduits (1/3 of Veronica), are possibly more recent, formed during interglacials and evolved close to a glacial body. The caves initiated in dolomitic marble under the influence of sulfuric acid speleogenesis (SAS) due to pyrite oxidation. The conduits were then enlarged dramatically under phreatic conditions. The caves have evolved since their preglacial formation, with phases of filling by fluvio-glacial sediments and unclogging. Water tracing and physico-chemical analysis attest to a well-karstified aquifer, with rapid water circulation (>20 m/h) and low temperatures (~2 °C), draining towards the main spring, "La Prediletta", located at the foot of the dolomitic marbles. Microclimatic records (cave temperature and humidity) show seasonal cycles of condensation and evaporation, influenced by air exchanges with the outside atmosphere. These processes contributed to the formation of secondary minerals by evaporation (gypsum, hydromagnesite…) and, above all, to the significant enlargement of passages by the retreat of walls with characteristic morphologies (facets and grooved walls). The Scerscen caves bear witness to a long geological and climatic history, from their formation before the Mid-Pleistocene ice ages to their present-day evolution. They offer valuable insights into karst processes in the high mountains, and interactions between glaciers and aquifers
Territoires nourriciers : que nous disent les bâtis des fermes en circuits courts ?
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Placement of Distributed Machine Learning Services for AI- and Smart Grid-Enabled IoT Platforms
No full textInternational audienceArtificial intelligence, fog computing, and smart grids allow for better energy management and personal data control. However, such heterogeneous platforms complexify service placement due to hardware and network heterogeneity. This paper proposes a distributed machine learning service for fog computing platforms model, and two new algorithms that aim to reduce time and energy consumption. The first algorithm groups services geographically, while the second places services vertically in the topology to reduce network usage. The Batsim simulator have been used to deploy distributed AI applications for measuring their duration and energy usage of the fog architecture. Results show that the first algorithm induces higher time and energy consumption than the second one, which outperforms multiple baseline algorithms for both metrics
Eating, inventing, and caring together: Ephemeral commensality in an experimental restaurant
No full textInternational audienceThis article examines how sociological research on food practices and emotions is ‘co-invented’ within experimental settings, treating cooking and eating as central to social organization. Drawing on two studies conducted at an experimental restaurant – a modular, camera-equipped space replicating cooking and dining environments – we analyze specific moments from our research through the lens of feminist reflections on the work of care in scholarly practice. Using methodographic analysis, we conceptualize eating in an experimental restaurant as a form of embodied collaborative invention emerging from interactions among humans, food, technical setups, and spatial arrangements. We identify three analytical knots: care for what bodies do and represent; care for playing with the field; and care for ephemeral commensality in collaborative cook–eat–think encounters. We argue that attention to small, often mundane moments of collaborative inventiveness nourishes an ongoing, situated quest for care in qualitative food research