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Avant les forêts froides : une approche morpho-architecturale et isotopique appliquée à Salix spp. pour explorer la physionomie des toundras tardiglaciaires de l’hémisphère Nord
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Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Resolving the Hot and Ionized Universe through the Sunyaev-Zeldovich effect
No full textInternational audienceAn omnipresent feature of the multi-phase ``cosmic web'' is that warm/hot (> K) ionized gas pervades it. This gas constitutes a relevant contribution to the overall universal matter budget across multiple scales, from the several tens of Mpc-scale IGM filaments, to the Mpc ICM, all the way down to the CGM surrounding individual galaxies, on scales from ~1 kpc up to their respective virial radii (~100 kpc). The study of the hot baryonic component of cosmic matter density represents a powerful means for constraining the intertwined evolution of galactic populations and large-scale cosmological structures, for tracing the matter assembly in the Universe and its thermal history. To this end, the SZ effect provides the ideal observational tool for measurements out to the beginnings of structure formation. The SZ effect is caused by the scattering of the photons from the cosmic microwave background off the hot electrons embedded within cosmic structures, and provides a redshift-independent perspective on the thermal and kinematic properties of the warm/hot gas. Still, current and future (sub)mm facilities have been providing only a partial view of the SZ Universe due to any combination of: limited angular resolution, spectral coverage, field of view, spatial dynamic range, sensitivity. In this paper, we motivate the development of a wide-field, broad-band, multi-chroic continuum instrument for the Atacama Large Aperture Submillimeter Telescope (AtLAST) by identifying the scientific drivers that will deepen our understanding of the complex thermal evolution of cosmic structures. On a technical side, this will necessarily require efficient multi-wavelength mapping of the SZ signal with an unprecedented spatial dynamic range (from arcsecond to degree scales) and we employ theoretical forecasts to determine the key instrumental constraints for achieving our goals. [abridged
Long-range propagation of airgun-array signals: Comparing numerical simulations and acoustic recordings in the Ionian sea
No full textInternational audienceMarine seismic surveys contribute to acoustic pollution, and the sounds they produce may be audible by marine mammals at several hundred kilometers distance. To evaluate the potential effects of such sounds on fauna and translate them into effective policies and mitigation measures, stakeholders require quantitative estimations of acoustic fields. We compare simulations of airgun-array signals produced during the Upper LIthosphere Ship Subduction Exploration survey in the Ionian Sea with the signals recorded 650 kilometers away at the cabled seabed observatory NEMO-SN1. JASCO's Applied Sciences' Airgun Array Source Model was used to predict the sound levels for two configurations of 18-element airguns, and the signal was then propagated in a realistic environment utilizing JASCO's Full-Waveform Range dependent Acoustic Model from the source to the position of the receiver station. There is a qualitative agreement between the simulated, denoised, and recorded signals of the airgun arrivals. However, the signal simulated at 650 kilometers from the source stretches and shows fewer high-frequency components compared to the received one. Our study quantitatively shows that the peaks produced by a large airgun array during a scientific cruise, at 160–180 Hz are not masked by ambient noise even in busy shipping locations at a distance of 650 km
Pottery use by the first Neolithic communities of Sardinia (Italy): functional analysis of vessels from Su Carroppu di Sirri, Carbonia
No full textInternational audienceThis work aims to contribute to the broad question of the role assigned to ceramic containers by the first Neolithic societies in the process of Neolithisation of the different Western Mediterranean regions, through a first assessment of the functional categorisation of the vessels used by Early Neolithic groups in the island of Sardinia (Italy). For this purpose, the pottery assemblage from Su Carroppu di Sirri (Carbonia, CI), in southwestern Sardinia, has been selected. This rock-shelter is one of the few excavated Early Neolithic sites in the island, providing evidence of human activities in the area during the 6th millennium cal BC, from the Cardial to the later Epicardial phase and the North Tyrrhenian Linear Carved Ware diffusion. After a comprehensive revision and refitting, the pottery assemblage has been investigated through an interdisciplinary functional approach, taking into consideration vessel morphotypology and morphometry, use-wear, and biomolecular and isotopic analysis of visible and absorbed organic residues by GC-FID, GC-MS and GC-C-IRMS. Despite the fragmentation of the assemblage and the low lipid recovery, functional categories can be outlined: cooking vessels, probably of different sizes (pots and bowls), for processing plant and unidentified (low lipid?) products, for alimentary and possibly non-alimentary purposes; open to low restricted bowls dedicated to processing contents without heating, with abrasive activities and/or low-lipid substances having an erosive potential; bowls with no distinctive alteration patterns, probably used for serving/eating; notably, large vessels, sometimes with handles and applied single or multiple cordon decoration, for storing ruminant dairy products, plants/animal fats and probably low-lipid contents; finally, closed necked jars, likely for storing/carrying liquids. Overall, in addition to the data about faunal remains and the use of chipped lithic implements, functional analysis of the pottery assemblage from Su Carroppu revealed the exploitation of different (plant and animal, domesticated and maybe wild) resources, and the storage and transport needs of the Early Neolithic human groups in the rock-shelter area
Educational Nudges and Teacher Agency in France’s School of Trust Paradigm
No full textInternational audienceThis article presents preliminary findings from an educational collaboration research study conducted in a middle school within the framework of the School of Trust paradigm. In classroom settings, teachers employ educational nudges as mediating tools to align their pedagogical activities with the principles of educational benevolence, fostering pupil self-regulation and volition. Grounded in activity theory, this case study utilized data from situated observations and reflective video-confrontation interviews with teachers to explore the impact of educational nudges on classroom dynamics. While self-reported data on student volition and self-regulation is limited, this study demonstrates how these tools enhance teacher agency and contribute to the transformation of traditional schooling practices. The findings suggest that educational nudges not only support student agency, but also empower teachers to innovate within the School of Trust paradigm, paving the way for a more benevolent and effective educational environment
Stellar intensity interferometry in the photon-counting regime
No full textInternational audienceStellar intensity interferometry consists in measuring the correlation of the light intensity fluctuations at two telescopes observing the same star. The amplitude of the correlation is directly related to the luminosity distribution of the star, which would be unresolved by a single telescope. This technique is based on the well-known Hanbury Brown and Twiss effect. After its discovery in the 1950s, it was used in astronomy until the 1970s, and then replaced by direct (“amplitude”) interferometry, which is much more sensitive, but also much more demanding. However, in recent years, intensity interferometry has undergone a revival. In this article, we present a summary of the state of the art, and we discuss in detail the signal-to-noise ratio of intensity interferometry in the framework of photon-counting detection
Investigating the impact of surfactant–salt feed solution on PTFE membrane performance under varying feed and permeate temperatures in membrane distillation
No full textInternational audienceMembrane distillation (MD) is a temperature-driven technology suitable for treating industrial wastewater, especially when utilizing low-grade heat sources like waste heat or renewable energy. Despite its potential, large-scale application of MD faces challenges due to high energy demands and operational instability caused by membrane fouling and wetting, particularly when surfactants are present. This study evaluated the thermal performance of a lab-pilot MD system using two commercial PTFE membranes. Initial experiments used saline feed solutions at varying feed and permeate temperatures. Subsequent tests introduced a non-ionic surfactant (Triton X-100), with and without NaCl, to investigate membrane fouling and wetting behavior. Results showed that higher feed temperatures increased permeate flux across all conditions, but also accelerated fouling and wetting, thereby shortening operational time. Notably, in the absence of NaCl, membrane degradation occurred more slowly, resulting in more stable performance. The novelty of this study lies in revealing the combined effect of salinity and non-ionic surfactants on the fouling and wetting performance of commercially available PTFE membranes in membrane distillation. Using a comprehensive two-stage experimental approach, the work systematically correlates MD system performance with membrane degradation mechanisms under feed conditions representative of real industrial wastewater. This dual focus not only uncovers the interplay between surfactants and salts but also provides practically relevant insights into the reliability and applicability of PTFE membranes in industrial MD operations
Lien entre schizophrénie très précoce et trouble du spectre de l’autisme : étude cas témoin rétrospective transversale
No full textLa schizophrénie infantile (COS) est un trouble neurodéveloppemental rare et grave. Sa phase prémorbide comprend des symptômes non spécifiques tels que des déficits cognitifs, des retards de langage et des troubles sociaux, qui recoupent ceux du trouble du spectre autistique (TSA). Il est à noter qu'environ un tiers des patients atteints de COS répondaient aux critères du TSA avant l'apparition de la psychose. Afin d'étudier ce chevauchement, nous avons examiné le développement précoce en comparant les évaluations de l’Autisme Diagnostic Interview-Revised (ADI-R) entre une cohorte de COS et un groupe témoin de TSA sans schizophrénie.Méthodes : les patients atteints de COS ont été inclus de manière prospective dans le protocole GenAuDiss, qui comprend des évaluations cliniques et génétiques, et ont été diagnostiqués à l'aide d'entretiens semi-structurés de référence (KSADS-PL). Le groupe témoin ASD a été sélectionné rétrospectivement à partir de la base de données Activis et a subi des évaluations de l'Autism Diagnostic Observation Schedule (ADOS-2) et ADI-R. Les groupes ont été appariés en fonction de l'âge et du sexe. Les scores ADI-R ont été comparés à l'aide du test de Wilcoxon, du test de Student et du test de Wilcoxon-Mann-Whitney, avec des ajustements de la valeur p.Résultats : soixante-dix participants (35 par groupe) ont été inclus. Le groupe COS présentait des sous-scores ADI-R significativement plus faibles dans les rubriques B2 (« incapacité à maintenir un échange conversationnel » ; p = 0,0001) et A4 (« manque de réciprocité socio-émotionnelle » ; p = 0,02). Les items spécifiques liés à la verbalisation sociale (item 34) et à la conversation réciproque (item 35) étaient plus altérés chez les patients atteints de TSA (p = 0,017). Des différences significatives ont également été observées pour l'item 56 (« Qualité des initiatives sociales ») et l'item 59 (« Pertinence des réponses sociales » ; p = 0,017).Conclusions : les patients atteints de COS présentaient moins de troubles de l'interaction sociale que les patients atteints de TSA, malgré des difficultés de communication similaires. Ces différences pourraient servir de marqueurs cliniques pour identifier les enfants présentant un risque plus élevé de schizophrénie au sein des populations atteintes de TSA. Une reconnaissance précoce et des interventions opportunes peuvent réduire la durée de la psychose non traitée, améliorant ainsi les résultats cliniques
Setting a Research Agenda for the Assessment and Treatment of Aphasia in Minority Languages
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Screening and host suitability assessment of nematicidal plants for root-knot nematode control
No full textInternational audienceRoot-knot nematodes (RKN), Meloidogyne species, are a top global threat associated with economic crop yield losses. They are difficult to detect and control, especially given the recent restrictions on environmentally harmful chemicals. There is a need for alternative solutions for sustainable RKN management, such as nematicidal plants (non-hosts or poor hosts). Despite extensive research, gaps remain in the understanding of nematicidal plant species and cultivars. Using our method, we evaluated the host suitability of 21 nematicidal plant candidates in climate chambers or glasshouses using a susceptible tomato control. Assessment was based on egg mass counts after one RKN cycle, as an indicator of reproduction. All the 21 candidates screened against Meloidogyne incognita were less infected than tomatoes, suggesting all the candidates are either non-or poor hosts. Tagetes species were evaluated against M. incognita, M. arenaria and M. enterolobii, with T. patula and T. erecta consistently non-hosts to the three RKN species. We also evaluated the number of galls as an indicator of the initiation of the RKN feeding sites and the plant's reaction. Only Tagetes spp. had no galls. Tagetes species Foeniculum vulgare and Crotalaria juncea were further assessed for M. incognita juvenile penetration and had significantly lower penetration than tomato, except for C. juncea. This suggests all Tagetes species and F. vulgare inhibit root penetration of most M. incognita juveniles at the rhizosphere level, while C. juncea attracts the nematodes and restricts reproduction. There is potential for most of the nematicidal plants to be used in cropping systems for sustainable integrated RKN management