Les marges sociales et les franges agricoles se tournent-elles le dos ?

Si un engouement croissant pour les produits locaux se fait sentir, force est de constater que ce changement dans la consommation alimentaire concerne surtout les quartiers centraux des villes et les populations à fort capital social et culturel. Le travail de recherche dont est issu cet article vise à questionner ce constat : les marges urbaines et leurs habitants sont-ils déconnectés des franges agricoles qui fournissent à la ville des produits alimentaires locaux et, si oui, pourquoi ? En s’appuyant sur la notion exploratoire de paysage alimentaire, nous avons voulu tester l’importance des représentations que les habitants des espaces urbains défavorisés ont des franges agricoles et des opportunités d’approvisionnement alimentaire qui en sont issues. Dans le cadre d’un travail de terrain et d’un projet en milieu scolaire mené dans le quartier des Minguettes (Vénissieux, agglomération lyonnaise), nous avons cherché à cerner les paysages alimentaires de plusieurs catégories d’acteurs et leur influence sur les modes de consommation alimentaire des habitants.Although there is an increasing demand for local produce this change in food consumption concerns principally people living in city centres with high social and cultural capital. The research presented in this article seeks to answer the following question : Are suburban areas and their inhabitants disconnected from the agricultural fringe areas which supply the city with local food products and, if so, why ? Based on the exploratory notion of the food landscape, we have sought to test the importance of the representations the inhabitants of disadvantaged urban areas have of the agricultural fringes and of the opportunities they provide as food sources. Within the framework of a field study and of a school project conducted in the Minguettes district (in Vénissieux in the agglomeration of Lyon), we have sought to identify the food landscapes of several types of stakeholders and their influence on the modes of food consumption of the inhabitants

Findings from the PP-SESAME experiment on board the Philae/ROSETTA lander on the surface of comet 67P

International audienceThe Permittivity Probe (PP-SESAME [1]) on-board the Philae Lander of the ROSETTA mission was designed to constrain the complex permittivity of the first 2 meters of the nucleus of comet 67P/Churyumov-Gerasimenko and to monitor its variations with time. Doing so, it is meant to provide unique insight into the composition (and activity if data could have been acquired longer) of the comet. In this paper, we present the analysis of the PP-SESAME measurements acquired during the first science sequence, on November 13, 2014, on the surface of the comet

The impact of lake shape and size on lake breezes and air-lake exchanges on Titan

Titan, the largest moon of Saturn, has many lakes on its surface, formed mainly of liquid methane. Like water lakes on Earth, these methane lakes on Titan likely profoundly affect the local climate. Previous studies (Rafkin and Soto 2020, Chatain et al 2022) showed that Titan's lakes create lake breeze circulations with characteristic dimensions similar to the ones observed on Earth. However, such studies used a model in two dimensions; this work investigates the consequences of the addition of a third dimension to the model. Our results show that 2D simulations tend to overestimate the extension of the lake breeze over the land, and underestimate the strength of the subsidence over the lake, due to divergence/convergence geometrical effects in the mass conservation equations. In addition, 3D simulations including a large scale background wind show the formation of a pocket of accelerated wind behind the lake, which did not form in 2D simulations. An investigation of the effect of shoreline concavity on the resulting air circulation shows the formation of wind currents over peninsulas. Simulations with several lakes can either result in the formation of several individual lake breeze cells (during the day), or the emergence of a large merged cell with internal wind currents between lakes (during the night). Simulations of several real-shaped lakes located at a latitude of 74{\deg}N on Titan at the spring equinox show that larger lakes trigger stronger winds, and that some sections of lakes might accumulate enough methane vapor to form a thin fog. The addition of a third dimension, along with adjustments in the parametrizations of turbulence and subsurface land temperature, results in a reduction in the magnitude of the average lake evaporate rate, namely to ~6 cm/Earth year.Comment: Submitted to Icarus on 2023-07-21. Dataset available at the DOI: 10.5281/zenodo.817227

The WISDOM Radar: Unveiling the Subsurface Beneath the ExoMars Rover and Identifying the Best Locations for Drilling

The search for evidence of past or present life on Mars is the principal objective of the 2020 ESA-Roscosmos ExoMars Rover mission. If such evidence is to be found anywhere, it will most likely be in the subsurface, where organic molecules are shielded from the destructive effects of ionizing radiation and atmospheric oxidants. For this reason, the ExoMars Rover mission has been optimized to investigate the subsurface to identify, understand, and sample those locations where conditions for the preservation of evidence of past life are most likely to be found. The Water Ice Subsurface Deposit Observation on Mars (WISDOM) ground-penetrating radar has been designed to provide information about the nature of the shallow subsurface over depth ranging from 3 to 10 m (with a vertical resolution of up to 3 cm), depending on the dielectric properties of the regolith. This depth range is critical to understanding the geologic evolution stratigraphy and distribution and state of subsurface H2O, which provide important clues in the search for life and the identification of optimal drilling sites for investigation and sampling by the Rover's 2-m drill. WISDOM will help ensure the safety and success of drilling operations by identification of potential hazards that might interfere with retrieval of subsurface samples

The Earthlike Shoreline Morphology of Titan's Ontario Lacus

Ontario Lacus' shoreline features include Earth-like rivers, deltas and flooded topography. Ontario is a dynamic lake, similar in many ways to terrestrial lakes, with active shoreline processes

Enceladus and Titan: Emerging Worlds of the Solar System (ESA Voyage 2050 White Paper)

Some of the major discoveries of the recent Cassini-Huygens mission have put Titan and Enceladus firmly on the Solar System map. The mission has revolutionised our view of Solar System satellites, arguably matching their scientific importance with that of their planet. While Cassini-Huygens has made big surprises in revealing Titan's organically rich environment and Enceladus' cryovolcanism, the mission's success naturally leads us to further probe these findings. We advocate the acknowledgement of Titan and Enceladus science as highly relevant to ESA's long-term roadmap, as logical follow-on to Cassini-Huygens. In this white paper, we will outline important science questions regarding these satellites and identify the pertinent science themes we recommend ESA cover during the Voyage 2050 planning cycle. Addressing these science themes would make major advancements to the present knowledge we have about the Solar System, its formation, evolution and likelihood that other habitable environments exist outside the Earth's biosphere

1H-NMR-Based Metabolic Profiling of Maternal and Umbilical Cord Blood Indicates Altered Materno-Foetal Nutrient Exchange in Preterm Infants

Background: Adequate foetal growth is primarily determined by nutrient availability, which is dependent on placental nutrient transport and foetal metabolism. We have used 1H nuclear magnetic resonance (NMR) spectroscopy to probe the metabolic adaptations associated with premature birth. Methodology: The metabolic profile in 1H NMR spectra of plasma taken immediately after birth from umbilical vein, umbilical artery and maternal blood were recorded for mothers delivering very-low-birth-weight (VLBW) or normo-ponderal full-term (FT) neonates. Principal Findings: Clear distinctions between maternal and cord plasma of all samples were observed by principal component analysis (PCA). Levels of amino acids, glucose, and albumin-lysyl in cord plasma exceeded those in maternal plasma, whereas lipoproteins (notably low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) and lipid levels were lower in cord plasma from both VLBW and FT neonates. The metabolic signature of mothers delivering VLBW infants included decreased levels of acetate and increased levels of lipids, pyruvate, glutamine, valine and threonine. Decreased levels of lipoproteins glucose, pyruvate and albumin-lysyl and increased levels of glutamine were characteristic of cord blood (both arterial and venous) from VLBW infants, along with a decrease in levels of several amino acids in arterial cord blood. Conclusion: These results show that, because of its characteristics and simple non-invasive mode of collection, cord plasma is particularly suited for metabolomic analysis even in VLBW infants and provides new insights into the materno-foetal nutrient exchange in preterm infants

Sous la brume, la surface de Titan

International audienceLa mission Cassini-Huygens a profondément enrichi notre connaissance de Titan. L'atmosphère de Titan, dominée par l'azote, est le siège d'une photochimie intense formant une vaste gamme de produits organiques allant de l'éthane à des aérosols complexes, hydrocarbures et nitriles. Ces aérosols (de taille submillimétrique) sont responsables de l'épaisse brume orangée qui, avec les nuages de méthane masquent la surface dans les domaines UV et visible ainsi que dans l'essentiel du domaine infrarouge. Sous cette épaisse couche de brume, Titan, la plus grande lune de Saturne, abrite des dunes géantes, des lacs d'hydrocarbures, des montagnes et des rivières. L'un des plus grands apports des la mission Cassini a été de révéler la surface sous la brume, comme nous le fait découvrir cet article

Les « révélations de soi » de l’enseignant en classe de FLE : dilemmes, risques et opportunités

With a focus on the analysis of “teachers’ cognition”, this work seeks to highlight the main dilemmas that foreign language teachers face when they decide to self-disclose in the classroom. Despite the numerous and positive uses that can be made of “self-disclosures” in class, teachers often refrain from using this “teaching tool”, or use it with great caution. Through a qualitative and inductive research based on interviews with several French as a Foreign Language teachers, occasionally complemented with class observations, we shed light on the tensions and dilemmas that shape teachers’ beliefs and practices in terms of “self-disclosure”. Furthermore, we share the pathways and solutions outlined by the teachers interviewed to foster a more productive and informed use of “self-disclosures” in the foreign language classroom.En se focalisant sur l’analyse de la pensée enseignante, ce travail se propose d’étudier les grands dilemmes auxquels les professeurs de langue se trouvent confrontés lorsqu’ils se livrent à des révélations personnelles en classe. En effet, malgré les usages multiples et bénéfiques qui peuvent être faits des révélations de soi, les enseignants se montrent souvent précautionneux, voire réticents, dans leurs recours à cet « outil pédagogique ». À travers une recherche qualitative et inductive, basée sur des entretiens compréhensifs menés auprès de différents enseignants de FLE, complétés ponctuellement par des observations de classe, nous mettons en lumière les tensions et dilemmes inhérents aux pratiques et croyances des enseignants en termes de révélations de soi. De plus, nous partageons les pistes et solutions esquissées par les enseignants interrogés pour en faire un usage opportun, judicieux et éclairé en classe de langue étrangère