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Citoyenneté et éducation : quelle éthique de la participation des enfants ?
No full textInternational audienceAccéder aux expériences citoyennes des enfants et des adolescents dans les contextes éducatifs constitue un enjeu majeur des recherches actuelles sur la construction des rapports à la citoyenneté dans l’enfance et à l’adolescence. A l’aune de la Convention Internationale des Droits de l’Enfant (CIDE, 1989) et de la conception de la citoyenneté développée par Chombart-de-Lauwe (1990), cet article examine les enjeux épistémologiques et méthodologiques liés à la prise en compte des points de vue des enfants, en particulier pour mieux comprendre l’exercice de la citoyenneté et penser le positionnement des adultes dans les contextes éducatifs. Les auteurs discutent ensuite des enjeux éthiques et psychologiques liés à la participation des enfants, au regard des nombreux paradoxes qui subsistent aujourd’hui concernant l’évolution du statut de l’enfant-citoyen, sa place dans la société et dans la recherche et l’exercice de ses droits de participation
The Borrachudos Granitic Suite: Paleo- to Mesoproterozoic A-type Magmatism in the Southeastern São Francisco Craton (SE Brazil)
No full textInternational audienceThe Borrachudos Granitic Suite (BGS) comprises an acid magmatism that occurred in the west edge of Araçuaí orogen (Late Neoproterozoic), southeastern Brazil.Previous papers attributed the magma genesis to crustal thickening related to an older Paleoproterozoic, Transamazonian orogeny. However, geochronological data indicate that BGS is younger, dominated by about 1.7 Ga granitoids hosted in the archean basement. To investigate the nature of this magmatism, mineralogical, geochemical, Nd-Sr isotopic studies in the BGS and genetically related metarhyolites inside the fold belt were carried out. High SiO 2 , K, Fe, F, Nb, Y, Zr and REE contents characterize granitoids and metarhyolites. The suite has ENd (T) values of -10.10 and -6.17, with T DM of 2.6-3.0 Ga, and initial 87 Sr/ 86 Sr ratio of 0.7057, indicating features of alkaline and anorogenic (A-type) within plate granitic magmas, derived from a Proterozoic crustal source. Therefore, we argue that an orogenic model for this magmatism is not viable. We propose that BGS is associated to crustal melting induced by mantle diapirism or mantle derived magmas related to the Paleoproterozoic extensional tectonic that produced crustal rifting, westward, precursory to the Espinhaço Supergroup basin. Beryl-and topaz-rich pegmatites of NYF-type intruded the granites as well as nearby host gneisses during BGS evolution.</p
Crystal Structures of Three Polymorphs of Cs 3 ScF 6 by Means of Solid-State NMR, X-Ray, and Neutron Diffraction
No full textInternational audienceThree polymorphs were found to exist for Cs3ScF6 in the room temperature range of up to 280 °C. Two phase transitions were identified by differential scanning calorimetry (DSC) analyses at 92 and 196 °C upon heating. In situ high-temperature solid-state NMR, synchrotron and laboratory X-ray diffraction, and neutron powder diffraction were used for structural characterization. The crystal structure of the high-temperature (γ) phase adopts the cubic Fm3̅m (Z = 4) space group with a = 9.6048(7) Å at 250 °C. The other two polymorphs, α and β, have tetragonal symmetry with space groups I41/a (Z= 80) and I4/m (Z= 10), and lattice parameters are a = 21.15222(6) Å, c = 38.21648(8) Å and a = 15.0401(2) Å, c = 9.6341(2) Å at RT and 150 °C, respectively
Model predictive game control for personalized and targeted interactive assistance
No full textContact robots are increasingly used to assist humans in physical training and manufacturing tasks. However, the effectiveness of current systems is limited as their control focuses on the system performance without explicitly considering the upcoming human user’s control. Here we present a differential game-based controller for contact robots that ensures optimal interaction with the human user by predicting their control during movement while considering their inherently finite planning horizon. Using this model-predictive game (MPG) controller, we systematically investigated human-robot co-adaptation in experiments, demonstrating that: (a) interaction with MPG remains stable for all participants while effectively reducing human effort; (b) the robot adapts to human behavior, identifying and characterizing individual motor control strategies that remain consistent over time and may be used as control biomarkers; (c) the human adapts to the robot’s behavior, and their interaction behavior can be modulated through an assistance meta-parameter. These findings indicate that humans can understand and adapt to a partner’s control strategy during movement, thereby exhibiting behavior consistent with game theory principles. Furthermore, the ability of the assistance meta-parameter to guide human users toward specific interaction behaviors can be used to develop versatile robot-assisted learning systems for physical training and rehabilitation
Tracing magnetic switchbacks to their source: An assessment of solar coronal jets as switchback precursors
No full textInternational audienceContext. The origin of large-amplitude magnetic field deflections in the solar wind, known as magnetic switchbacks, is still under debate. These structures, which are ubiquitous in the in situ observations made by Parker Solar Probe (PSP), likely have their seed in the lower solar corona, where small-scale energetic events driven by magnetic reconnection could provide conditions ripe for either direct or indirect generation.Aims. We investigated potential links between in situ measurements of switchbacks and eruptions originating from the clusters of small-scale solar coronal loops known as coronal bright points to establish whether these eruptions act as precursors to switchbacks.Methods. We traced solar wind switchbacks from PSP back to their source regions using the ballistic back-mapping and potential field source surface methods, and analyzed the influence of the source surface height and solar wind propagation velocity on magnetic connectivity. Using extreme ultraviolet images, we combined automated and visual approaches to identify small-scale eruptions (e.g., jets) in the source regions. The jet occurrence rate was then compared with the rate of switchbacks captured by PSP.Results. We find that the source region connected to the spacecraft varies significantly depending on the source surface height, which exceeds the expected dependence on the solar cycle and cannot be detected via polarity checks. For two corotation periods that are straightforwardly connected, we find a matching level of activity (jets and switchbacks), which is characterized by the hourly rate of events and depends on the size of the region connected to PSP. However, no correlation is found between the two time series of hourly event rates. Modeling constraints and the event selection may be the main limitations in the investigation of a possible correlation. Evolutionary phenomena occurring during the solar wind propagation may also influence our results. These results do not allow us to conclude that the jets are the main switchback precursors, nor do they rule out this hypothesis. They may also indicate that a wider range of dynamical phenomena are the precursors of switchbacks
An Experimental Study Of The Vortical Structures In Supersonic Steam Jet Impinged On To The Wall
No full textInternational audienceThis study presents an experimental investigation into the impingement of a supersonic steam jet onto a wall. Steam was injected through a supersonic nozzle at a varying total pressure of 1.5-3.0 bars, producing a supersonic steam jet at a pressure gradient of 0.5-2.0 bars. The whole fluid domain is comprised of two regions: the jet region and the region near the wall involving the impingement of the supersonic steam jet. Within this region, the transformation of primary vortices into secondary vortices occurs and these vortices expel outward in the radial direction after impingement. Measurements have shown the spreading of the normalized density of the vortical structures along the axial length within the region near the wall. However, the probability density function analysis has indicated that the vortical structures become denser within the impingement region. Whereas subsequent to an impingement of the steam jet onto the wall, along the radial direction, weak traces of their existence in the jet region may be attributed to the vorticity diffusion within the jet region
Examen de l'hétérogénéité et des programmes de thérapie miroir pour lutter contre les douleurs du membre fantôme : une scoping review
No full textInternational audienceBackground: Mirror therapy shows promise in the treatment of phantom limb pain but lacks robust evidence. Objectives: To address this gap, we conducted a scoping review aiming to comprehensively explore the landscape of mirror therapy practice, gather details about the session content, and offer recommendations for future research. Method: We searched seven databases for published work from 1995 to May 2023. Two independent reviewers selected, assessed, and extracted data from eligible articles. Articles, regardless of study design, were considered eligible if they investigated mirror therapy as an intervention for phantom limb pain. Results: A total of 44 articles were included, comprising 16 randomized control trials, 14 prospective cohort studies, 15 case reports, and 3 protocols. These studies collectively involved 942 patients, with male patients representing 70 % of the participants. Lower limb amputation, primarily attributed to trauma, accounted for 88 % of the included patients. Pain intensity was predominantly assessed by a visual analog scale (61 %). However, there was a notable absence of detailed descriptions regarding mirror therapy sessions, particularly concerning the number of exercises, duration per exercise, and repetitions. Typically, sessions lasted 15 min each, conducted once daily. The exercises primarily focused on motor exercises targeting the distal part of the limb. Conclusion:The practice of mirror therapy was characterized by poor description, showed significant heterogeneity, and a lack of standardized protocols, which contributes to an overall low level of evidence. Addressing these gaps in practice description and standardization is crucial for improving reproducibility and strengthening the evidence base for the prescription of mirror therapy.</div
Cryogenic cyclical etching of Si using CF plasma passivation steps: The role of CF radicals
No full textInternational audienceThis article is selected by the editors of APL as Featured Collection. Ultraviolet (UV) absorption spectroscopy is used to monitor the CF radical density in CF4 inductively coupled plasma (ICP) plasmas as a function of the substrate temperature. The CF density decreases dramatically when the wafer temperature is reduced from 20 to −130 °C by applying identical plasma conditions, demonstrating that the CF surface sticking coefficient increases as the surface temperature is reduced. This suggests that CF4 plasma could be used to form sidewall passivation layers and perform anisotropic etching at cryogenic temperature, which is impossible at room temperature. Subsequently, a cyclical Bosch type etching process of silicon was evaluated at −100 °C using CF4 plasma to passivate the trench sidewalls. Anisotropic etch profiles were obtained with an etch rate of 4.4 μm/min. Compared to a typical Bosch process using highly polymerizing c-C4F8 plasma, chamber wall contamination could be significantly reduced, alleviating a major issue of this cyclic process. Furthermore, CF4 has a 28% lower global warming potential than c-C4F8