Les années Johnson : ruptures, continuités et héritage

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Taking Titan’s Boreal Pole Temperature: Evidence for Evaporative Cooling in Ligeia Mare

International audienceFrom 2004 to 2017, the Cassini RADAR recorded the 2.2 cm thermal emission from Titan's surface in its passive (radiometry) mode of operation. We use this data set to investigate the seasonal evolution of the effective temperature sensed by the microwave radiometer in two regions in the northern pole of the satellite: the sea Ligeia Mare, and its nearby solid terrains. We find that despite the arrival of summer at the end of the mission, the effective temperature of Ligeia Mare decreased by almost 1 K, while that of the solid region slowly increased until 2017 by 1.4 ± 0.3 K. These observations, as well as the lag in summer warming observed by Cassini's Composite Infrared Spectrometer, can be explained by evaporative cooling in both the solid and liquid surfaces after the vernal equinox. It therefore supports the idea that the northern polar terrains are wet. Using an ocean circulation model, we show that the cooling of the sea surface should initiate convection in the sea's interior, ultimately cooling the whole liquid column sensed by the Cassini radiometer and thus decreasing the temperature at depths even long after the evaporation period has ceased. Overall, this work highlights the key role of methane hydrology in controlling the surface and submarine temperatures in the boreal polar regions of Titan

Towards Determining the Earth Energy Imbalance from Space - Outcome of a recent ISSI International Team

International audienceA positive Earth Energy Imbalance (EEI) is the energy, which is continuously stored by the Earth and will ultimately released to the atmosphere, causing global warming. The "imperative to monitor Earth’s energy imbalance” (von Schuckmann et al., 2016) has been continuously reported by the Earth’s climate community. The EEI has been identified to be around 0.5 to 1.0 Wm−2. To determine its exact value both the Total Solar Irradiance (TSI) and the Top of the Atmosphere (ToA) Outgoing Radiation (TOR) need to be measured with unprecedented accuracy and precision.However, so far, the EEI could not be determined as the measurements were not sufficiently accurate. This calls for improved instrument technologies as well as a traceable calibration chain of the space instrumentation. To pave the way in that direction, the ISSI International Team "Towards Determining the Earth Energy Imbalance from Space" has been established. We collect the current knowledge of ERB measurements and identify missing elements for measuring EEI from space. Specifically, we collect past and ongoing measurements of the ERB components obtained with instruments such as CLARA, RAVAN, SIMBA, GERB, and CERES. The goal is to evaluate the performance and uncertainty of each of the instruments to identify observational challenges that need to be overcome to be able to measure both TSI and the Earth’s outgoing radiation with the required accuracy to ultimately be able to determine the absolute level of EEI from space

Évolution de la fréquence des cancers en France

International audienceWe present and discuss recent data on the frequency of cancer in France. In the male population, the incidence of cancer has been stable since 2010 and mortality is decreasing; changes in the incidence of all cancers are dominated by changes in the incidence of prostate cancer, which is highly dependent on the extent of screening. In the female population, cancer incidence is rising and mortality is falling; the increase in the incidence of all cancers is partly due to the rise in the incidence of lung cancer, a consequence of women taking up smoking in the early 1970s.Nous présentons et discutons les données récentes sur la fréquence des cancers en France. Dans la population masculine, l’incidence du cancer est stable depuis 2010 et la mortalité diminue. L’évolution de l’incidence de l’ensemble des cancers est dominée par l’évolution de l’incidence du cancer de la prostate très dépendante des pratiques de dépistage. Dans la population féminine, l’incidence du cancer augmente et la mortalité diminue. L’augmentation de l’incidence de l’ensemble des cancers est en partie due à l’augmentation de l’incidence du cancer du poumon, conséquence de l’entrée des femmes dans le tabagisme au début des années 1970

Ionospheric environment of Ganymede during the Galileo flybys

International audienceThe Galileo spacecraft flew by Ganymede, down to 0.1 RG from the surface for the closest, six times giving us insight into its plasma environment. Its ionosphere, made of ions born from the ionisation of neutrals present in Ganymede’s exosphere, represents the bulk of the plasma near the moon around closest approach. As it has been revealed by Galileo and Juno, near closest approach the ion population is dominated by low-energy ions from the water ion group (O+, HO+, H2O+) and O2+. However, little is known about their density, spatial distribution, and effect on the surface weathering of the moon itself. Galileo G2 flyby has been extensively studied. Based on a comparison between observations and 3D test-particle simulations, Carnielli et al. (2020a and 2020b) confirmed the ion composition (debated at the time), highlighted the inconsistency between the assumed exospheric densities and the observed ionospheric densities, and derived the contribution of ionospheric ions as an exospheric source. However, other flybys of Ganymede are also available (e.g. G1, G7, G8, G28, and G29) providing in-situ measurements at different phases of Ganymede around Jupiter or jovian magnetospheric conditions at the moon. We extend the original study by Carnielli et al. to other flybys, and compare our modelled ion moments (ion number density, velocity, and energy distribution) with Galileo in-situ data. We discuss our results and contrast them with those obtained for the G2 flyby.   &#160

Identifier les écarts entre les représentations du métier d'étudiante par les étudiantes et par les enseignantes

International audienceA great deal of research has focused on the transition from high school to university and how students manage to adapt to this new environment. It shows that there is a gap between the culture 'inherited' from secondary school and the university. However, the university still seems to underestimate the importance of initial acculturation, which provides access to academic codes, norms and practices (Paivandi, 2019). The aim of the research presented here is to identify the beliefs of what it means to be a student for newcomers and for teachers, and to compare them in order to identify potential discrepancies. We hypothesise that these discrepancies may give rise to misunderstandings that are a potential source of difficulties for newcomers. We carried out an exploratory study of students' beliefs about autonomy and autonomy in their work at university, with newcomers in the faculty of Sciences of the Université Paris Saclay and with their full professors. In both cases, the questionnaire sent out to students and lecturers contained 3 questions, dealing respectively with the student's autonomy, her personal work and the expectations of lecturers in practical and practical work. To analyse the 6 verbatim corpora (3 questions, for each of the 2 communities), a thematic content analysis was carried out based on the 7 dimensions of empowerment proposed by Albero (2004), and adapted to the context. We adopted an analysis approach combining an a priori grid and its progressive enrichment during corpus processing: sub-dimensions and categories were formulated in relation to the different dimensions. Double-blind coding of the verbatims was carried out. The significant differences between the dimensions and sub-dimensions mentioned in the teachers and students verbatims were calculated. This revealed differences between the various dimensions, which were not the same for the 3 questions. For example, with regard to autonomy, more students verbatims were identified as relating to the sub-dimensions "Managing difficulties and emotions" and "Self-management and being responsible. On the contrary, the metacognitive sub-dimension "Regulating one's practices" was identified in more teachers verbatims. With regard to personal work, more students verbatims were identified as coming under the institutional dimension, and in particular the sub-dimension "Adapting to the teacher". Finally, with regard to expectations for practical work, more teachers verbatims were identified under the sub-dimension "Motivation, commitment, perseverance", whereas the students' expectations fell under the methodological dimension. These discrepancies between newcomers’ beliefs and teachers' beliefs could be use to thought about the support to facilitate the acculturation process for newcomersDe nombreuses recherches concernent la transition entre l’enseignement secondaire et l’enseignement supérieur et la façon dont les étudiantes arrivent à s’adapter à ce nouvel environnement. Il en ressort un décalage entre la culture « héritée » du passé lycéen et le monde universitaire. Toutefois, le système universitaire semble encore sous-estimer l’importance d’une acculturation initiale permettant l’accès aux codes, aux normes et aux pratiques académiques (Paivandi, 2019). Les recherches présentées ici visent à identifier les représentations et implicites du métier d’étudiante par les étudiantes et par les enseignantes, et à les mettre en regard afin de faire émerger des potentiels écarts. Nous faisons l’hypothèse que ces écarts peuvent donner lieu à des malentendus potentiellement source de difficultés pour les étudiantes. Nous avons mené une étude exploratoire portant sur les représentations de l’autonomie de l’étudiante et dans son travail, auprès des étudiantes entrant en L1 à l’UFR des Sciences de l’Université Paris Saclay et auprès de leurs enseignantes. Le questionnaire adressé aux étudiantes et aux enseignantes comportait 3 questions ouvertes, portant respectivement sur l’autonomie de l’étudiante, son travail personnel et les attentes des enseignantes en TP et TD. Pour analyser les 6 corpus de verbatim (3 questions ouvertes, pour chacune des 2 communautés), une analyse de contenu thématique a été réalisée en s’appuyant sur les 7 dimensions de l’autonomisation proposées par Albero (2004), et adaptées au contexte. Nous avons adopté une approche d’analyse articulant la grille a priori et son enrichissement progressif lors du traitement des corpus : en lien avec les différentes dimensions, des sous dimensions et catégories ont été formulées. Un codage en double aveugle des verbatims a été réalisé. La significativité des écarts entre les dimensions et les sous-dimensions évoquées dans les verbatims enseignantes et étudiantes a été calculée. Elle met en évidence des écarts sur les différentes dimensions, qui ne sont pas les mêmes pour les 3 questions. Par exemple, concernant l’autonomie, davantage de verbatims étudiantes que de verbatims enseignantes ont été identifiés comme relevant de la dimension psycho-affective, et notamment des sous-dimensions « Gérer les difficultés, les émotions » et « S’auto-gérer et être responsable ». A l’inverse, davantage de verbatims enseignantes qu’étudiantes ont été identifiés comme relevant de la dimension métacognitive « Réguler ses pratiques ». Concernant le travail personnel, davantage de verbatims étudiantes ont été identifiés comme relevant de la dimension institutionnelle, et notamment de la sous-dimension « S’adapter à l’enseignant ». Enfin, concernant les attentes en TD et TP, davantage de verbatims enseignantes ont été identifiés comme relevant de la sous-dimension « Se motiver, s’engager, persévérer », alors que ceux des étudiantes relèvent de la dimension méthodologique. L'identification de ces écarts entre représentations des étudiantes et implicites des enseignantes peut nourrir les réflexions sur l’accompagnement à mettre en place pour faciliter le processus d’acculturation des étudiantes arrivant en 1ère année à l’université

The M-MATISSE mission: Mars Magnetosphere ATmosphere Ionosphere and Space weather SciencE. An ESA Medium class (M7) candidate in Phase-A.

International audienceThe "Mars Magnetosphere ATmosphere Ionosphere and Space-weather SciencE (M-MATISSE)" mission is an ESA Medium class (M7) candidate currently in Phase A study by the European Space Agency (ESA) (Figure 1). M-MATISSE's main scientific goal is to unravel the complex and dynamic couplings of the Martian Magnetosphere, Ionosphere and Thermosphere (M-I-T coupling) with relation to the Solar Wind (i.e. space weather) and the lower atmosphere, and the processes leading to this coupling, which are highly entangled between several regions of the system (Figure 2). The M-I-T coupling controls the dissipation of incoming energy from the solar wind, and therefore, the evolution of Mars' atmosphere and climate (including atmospheric escape, auroral processes, and incoming radiation). Moreover, understanding the behavior of Mars' M-I-T system and of the chain of processes that control Space Weather and Space Climate at Mars, as well as the radiation environment, is essential for exploration as it leads to accurate Space Weather forecasts and, thus, prevents hazardous situations for spacecraft and humans

A spherical and heterogeneous radiative transfer code for near-infrared remote sensing: application to Titan

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Concepts for the development of person-centred, digitally-enabled, Artificial Intelligence-assisted ARIA care pathways (ARIA 2024)

International audienceThe traditional healthcare model is focused on diseases (medicine and natural science) and does not acknowledge patients' resources and abilities to be experts in their own life based on their lived experiences. Improving healthcare safety, quality and coordination, as well as quality of life, are important aims in the care of patients with chronic conditions. Person-centred care needs to ensure that people's values and preferences guide clinical decisions. This paper reviews current knowledge to develop (i) digital care pathways for rhinitis and asthma multimorbidity and (ii) digitally-enabled person-centred care (1). It combines all relevant research evidence, including the so-called real-world evidence, with the ultimate goal to develop digitally-enabled, patient-centred care. The paper includes (i) Allergic Rhinitis and its Impact on Asthma (ARIA), a two-decade journey, (ii) Grading of Recommendations, Assessment, Development and Evaluation (GRADE), the evidence-based model of guidelines in airway diseases, (iii) mHealth impact on airway diseases, (iv) from guidelines to digital care pathways, (v) embedding Planetary Health, (vi) novel classification of rhinitis and asthma, (vi) embedding real-life data with population-based studies, (vii) the ARIA-EAACI strategy for the management of airway diseases using digital biomarkers, (viii) Artificial Intelligence, (ix) the development of digitally-enabled ARIA Person-Centred Care and (x) the political agenda. The ultimate goal is to propose ARIA 2024 guidelines centred around the patient in order to make them more applicable and sustainable

Food chain without giants: modelling the trophic impact of bowhead whaling on little auk populations in the Atlantic Arctic

International audienceIn the Atlantic Arctic, bowhead whales (Balaena mysticetus) were nearly exterminated by European whalers between the seventeenth and nineteenth centuries. The collapse of the East Greenland–Svalbard–Barents Sea population, from an estimated 50 000 to a few hundred individuals, drastically reduced predation on mesozooplankton. Here, we tested the hypothesis that this event strongly favoured the demography of the little auk (Alle alle), a zooplanktivorous feeder competitor of bowhead whales and the most abundant seabird in the Arctic. To estimate the effect of bowhead whaling on little auk abundance, we modelled the trophic niche overlap between the two species using deterministic simulations of mesozooplankton spatial distribution. We estimated that bowhead whaling could have led to a 70% increase in northeast Atlantic Arctic little auk populations, from 2.8 to 4.8 million breeding pairs. While corresponding to a major population increase, this is far less than predicted by previous studies. Our study illustrates how a trophic shift can result from the near extirpation of a marine megafauna species, and the methodological framework we developed opens up new opportunities for marine trophic modelling