The diagnostic accuracy of lung ultrasound to determine PiCCO-derived extravascular lung water in invasively ventilated patients with COVID-19 ARDS

Background: Lung ultrasound (LUS) can detect pulmonary edema and it is under consideration to be added to updated acute respiratory distress syndrome (ARDS) criteria. However, it remains uncertain whether different LUS scores can be used to quantify pulmonary edema in patient with ARDS. Objectives: This study examined the diagnostic accuracy of four LUS scores with the extravascular lung water index (EVLWi) assessed by transpulmonary thermodilution in patients with moderate-to-severe COVID-19 ARDS. Methods: In this predefined secondary analysis of a multicenter randomized-controlled trial (InventCOVID), patients were enrolled within 48 hours after intubation and underwent LUS and EVLWi measurement on the first and fourth day after enrolment. EVLWi and ∆EVLWi were used as reference standards. Two 12-region scores (global LUS and LUS–ARDS), an 8-region anterior–lateral score and a 4-region B-line score were used as index tests. Pearson correlation was performed and the area under the receiver operating characteristics curve (AUROCC) for severe pulmonary edema (EVLWi &gt; 15 mL/kg) was calculated. Results: 26 out of 30 patients (87%) had complete LUS and EVLWi measurements at time point 1 and 24 out of 29 patients (83%) at time point 2. The global LUS (r = 0.54), LUS–ARDS (r = 0.58) and anterior–lateral score (r = 0.54) correlated significantly with EVLWi, while the B-line score did not (r = 0.32). ∆global LUS (r = 0.49) and ∆anterior–lateral LUS (r = 0.52) correlated significantly with ∆EVLWi. AUROCC for EVLWi &gt; 15 ml/kg was 0.73 for the global LUS, 0.79 for the anterior–lateral and 0.85 for the LUS–ARDS score. Conclusions: Overall, LUS demonstrated an acceptable diagnostic accuracy for detection of pulmonary edema in moderate–to–severe COVID-19 ARDS when compared with PICCO. For identifying patients at risk of severe pulmonary edema, an extended score considering pleural morphology may be of added value. Trial registration: ClinicalTrials.gov identifier NCT04794088, registered on 11 March 2021. European Clinical Trials Database number 2020–005447-23.</p

Etude de l'équilibre et de la circulation des populations d'électrons dans la magnétosphère de Saturne à l'aide des données multi-instrumentales de la sonde Cassini-Huygens.

This thesis consists in an original study of the equilibrium and the circulation of electron populations in Saturn's magnetosphere, from the Cassini multi-instrument data. Based on inter-calibrated composite spectra, from the low-energy data (CAssini Plasma Spectrometer, from 0.6 eV to 26 keV) and the high-energy data (Magnetospheric IMaging Instrument, from 12 keV to 1 MeV) I have identified the electron populations co-existing in Saturn's magnetosphere: one thermal population (a few eV), one suprathermal population (100-1000 eV), both dominant in the kronian magnetospheric environment, one energetic electron population (MeV), and one population of photoelectrons produced by photo ionization of the neutral cloud, identified for the first time in the inner magnetosphere (< 5 Rs). From the radial profiles of the dominant electron population moments I have identified the existence of three magnetospheric regions characterized by different plasma regimes, separated by two boundaries, at 9 and 15 Saturnian radii. Statistical analysis of the electron moment radial profile has revealed a highly dynamic plasma sheet, and an asymmetry of the thermal and the suprathermal electron populations in longitude. The analysis of the fluid moment evolution inside and between magnetospheric regions allowed identifying the source, the sink and the transport regions of the electron populations on one hand, and the physical processes operating in these regions on the other hand. Based on this analysis, an electron population scheme in Saturn's magnetosphere is finally suggested.Ce travail de thèse est une étude originale de l'équilibre et de la circulation des populations d'électrons dans la magnétosphère de Saturne à l'aide des données multi-instrumentales de la sonde Cassini-Huygens. A partir de spectres inter-étalonnés des instruments particules de basse énergie (de 0.6 eV à 26 keV) et de haute énergie (de 12keV à 1 MeV), j'ai identifié les populations électroniques présentes dans la magnétosphère de Saturne : une population thermique (quelques eV), une population suprathermique (100-1000 eV), une population d'électrons énergétiques (MeV), et une population de photoélectrons issus de la photo-ionisation du tore de gaz neutre, observée pour la première fois dans la magnétosphère interne (< 5 Rayons saturniens). A partir des profils radiaux des moments fluides des populations électroniques dominantes, j'ai identifié la présence de 3 grandes régions magnétosphériques caractérisées par des régimes plasma différents, séparées par deux frontières localisées à 9 et à 15 Rayons saturniens. L'analyse statistique des profils de moments a révélé une dynamique importante de la couche de plasma et une asymétrie de la distribution des électrons thermiques et suprathermiques en longitude. L'analyse de l'évolution des moments fluides à l'intérieur de chacune des régions magnétosphériques et entre ces régions m'a permis d'identifier d'une part les régions de source, de perte et de transport des populations électroniques, et d'autre part les processus physiques dominants dans ces régions. Sur base de cette analyse, un schéma de circulation des populations d'électrons dans la magnétosphère de Saturne est enfin proposé

Etude de l'équilibre et de la circulation des populations d'électrons dans la magnétosphère de Saturne à l'aide des données multi-instrumentales de la sonde Cassini-Huygens

TOULOUSE3-BU Sciences (315552104) / SudocTOULOUSE-Observ. Midi Pyréné (315552299) / SudocSudocFranceF

Wind and Wave Expert Centre at LATMOS (CAL/VAL Activities)

International audienc

Statistical analysis of Saturn's UV auroral outer emission

Recent observations of Saturn’s aurora with the UVIS spectrograph on-board Cassini not only confirm the presence of a quasi-permanent partial ring of emission equatorward of the main auroral oval, but they also increase the number of positive cases and allow for a statistical analysis of the characteristics of this outer emission. This faint but distinct auroral feature appears at both hemispheres in the nightside sector. It magnetically maps to relatively large distances in the nightside magnetosphere, on the order of 9 RS. It was initially thought that pitch angle scattering of electrons into the loss cone by whistler waves would be responsible for the outer auroral emission. Rough estimates suggested that a suprathermal electron population observed with Cassini in the nightside sector between 7 and 10 RS might power this process. However, a new analysis of 7 years of Cassini electron plasma data indicates the presence of layers of upward and downward field aligned currents. They appear to be part of a large-scale current system involving dayside-nightside asymmetries as well as trans- hemispheric variations. This system comprises a net upward current layer, carried by warm electrons, limited to the nightside sector which may as well generate the outer UV auroral emission. The growing dataset of UVIS spectro- images is used to find any such asymmetries in the outer auroral emission

Directional and Frequency Spread of Surface Ocean Waves from CFOSAT/SWIM Measurements

International audienceThe CFOSAT (China France Oceanography Satellite) mission launched in 2018 now routinely provides at the global scale, directional spectra of ocean waves. The principle is based on the analysis of the normalized radar cross-section measured by the instrument SWIM (Surface Waves Investigation and Monitoring), a near-nadir pointing Ku-Band real-aperture scanning radar. From the ocean wave spectra derived from SWIM, the principal parameters of ocean wave spectra as significant wave height, peak wavelength, and peak direction are now available to better characterize the sea-state. However, it is known that these principal parameters are not sufficient not fully characterize the distribution of wave energy and understand or validate the physical processes impacting its evolution during growth order decay. Here we show that the parameters characterizing the shape of the wave spectra (e.g directional and frequency spread) can be estimated at the global scale from the SWIM measurements. We also show that they can provide consistent values of the Benjamin-Feir index, an index proposed to estimate the probability of extreme waves. Similarities of differences with the shape parameters of the MFWAM numerical wave model are also discussed

Nanodust detection at 1 AU from radio spectra analysis on Cassini

International audienc

CFOSAT: un nouveau satellite pour la mesure du vent et des vagues à partir de deux instruments radar en bande Ku

International audienceLa mission spatiale CFOSAT (China France Oceanography SATellite) a été conçue pour répondre au besoin d'amélioration des connaissances concernant les caractéristiques de la surface océanique (vent, vagues), et leurs impacts sur les échanges entre l'atmosphère et l'océan qui jouent un rôle majeur dans le système climatique. Elle permettra par exemple d'étudier des aspects mal connus du rôle des vagues sur les basses couches de l'atmosphère, sur l'océan super-ficiel, et sur la glace de mer en zone polaire. De manière complémentaire aux autres observations spatiales actuelles, CFOSAT permettra de fournir des observations cruciales pour la prévision atmosphérique, la prévision de l'état de la mer, et la modélisation numérique du système couplé océan-atmosphère. Elle apportera également une description précise des conditions de vagues en haute mer qui conditionnent l'impact des vagues sur l'évolution des zones littorales. CFOSAT est une mission originale à plusieurs titres. En premier lieu, il s'agit de la première coopération pour une mission spatiale conjointe entre la France et la Chine, qui ont uni leurs compétences et moyens pour développer et mettre en oeuvre de nouveaux concepts de mesure depuis l'espace. Ainsi, le satellite embarque deux instruments radar fonctionnant en bande Ku, l'un dédié à la mesure du vent (SCAT conçu et développé en Chine), l'autre (SWIM, conçu et développé en France), dédié à la mesure des propriétés détaillées des vague

Nanodust detection at 1 AU from radio spectra analysis on Cassini

International audienc