Publications scientifiques de l'Université de Reims Champagne-Ardenne
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Patterns of relapse after postoperative radiotherapy in patients with oral cavity cancer and a flap
No full textInternational audienc
Fault segmentation, geometry and recent activity in the epicentral area of the 1956 Mw 7.5 Amorgos earthquake (Greece)
No full textInternational audienceThe Amorgos-Santorini region (Hellenic Volcanic Arc, Greece), suffered the most powerful earthquake in the Mediterranean in the 20th century (1956, Mw ~7.5). This event caused casualties, severe damage and a large tsunami. The epicentral area is offshore and is characterized by several basins bounded by submarine faults accommodating back-arc extension and the Anatolian extrusion. Recently, the Amorgos fault was identified as the causative fault of the 1956 Amorgos earthquake. However, the characteristics of this fault, such as its detailed geometry, segmentation and kinematics remain unclear and debated. Using new high-resolution bathymetric data and sediment cores, we present a detailed mapping of this fault and its neighbors.The Amorgos fault is composed of three segments separated by relay zones. Taking into account the onshore geology, where E-W striking late Miocene normal faults are mapped, the segmentation could be controlled by structural heritage. Offshore, all but the southernmost segments of the Amorgos fault exhibit cumulative scarps of at least 700 m in relief. The segments strike NE-SW, except for the northern one that displays a curved structure in its middle, at 60° with respect to the main fault (E-W striking).The central segment, where evidences of the 1956 earthquake rupture were found, is composed of several secondary faults that offset young geomorphic features at the seafloor (such as mass-wasting scars) with purely normal kinematics. In comparison, the curved northern segment shows fewer secondary faults, none of them offsetting the numerous mass-wasting scars observed along its trace. We also find here secondary NE-SW faults that are crosscutting its cumulative scarps, and are offsetting the Last Glacial Maximum wave-cut platform by up to 5 meters, testifying for their recent activity. These observations question the role of the northern E-W striking segment in the accommodation of the present-day stress regime (NW-SE extension), that may be now inactive, or activated as a strike-slip fault, although we do not observe markers laterally offset. We discuss how the geometry and segmentation of the Amorgos fault can impact the rupture propagation, especially in relation to the 1956 earthquake and morphology of the nearby faults
Conditions LMIs pour la détectabilité des modes des systèmes à commutations identifiés avec la méthode de distance minimum
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The atmosphere of Titan in late northern summer from JWST and Keck observations
No full textInternational audienceSaturn's moon Titan undergoes a long annual cycle of 29.45 Earth years. Titan's northern winter and spring were investigated in detail by the Cassini-Huygens spacecraft (2004-2017), but the northern summer season remains sparsely studied. Here we present new observations from the James Webb Space Telescope (JWST) and Keck II telescope made in 2022 and 2023 during Titan's late northern summer. With JWST's Mid-Infrared Instrument we spectroscopically detected the methyl radical, the primary product of methane breakup and key to the formation of ethane and heavier molecules. With JWST's Near Infrared Spectrograph we detected several non-LTE CO and CO2 emission bands that allow measurement of these species over a wide altitude range. Lastly, with JWST's Near Infrared Camera and Keck II we imaged northern hemisphere tropospheric clouds evolving in altitude, providing new insights and constraints on seasonal convection patterns. These observations pave the way for new observations and modeling of Titan's climate and meteorology as it progresses through northern Fall equinox, when its atmosphere is expected to show dramatic seasonal changes
Entretien professionnel : le N + 1 sinon rien
No full textInternational audienceNote sous CAA Paris, 23 octobre 2024, no 23PA0197
Vers un apprentissage non supervisé performant, le cas de la segmentation d’images biomédicales
No full textNational audienceLa question de l’apprentissage non supervisé en segmentation est toujours d’actualité du fait de la complexité des structures et de la haute dimensionnalité des données traitées. En partant d’une stratégie d’adaptation de domaine non supervisée, nous montrons comment l’ajuster pour en faire une méthode efficace capable de s’entraîner sur de nouvelles données sans étiquettes. Nous proposons d'exploiter les prédictions de Segment Anything (SAM). Les images biomédicales contiennent une grande variété d'objets, de sorte que SAM est capable de produire une segmentation de haute qualité, mais pas nécessairement de segmenter les objets d'intérêt. Par conséquent, nous introduisons un réseau de raffinement pré-entraîné sur une base annexe, qui améliore la prédiction de SAM. Enfin, nous utilisons ce réseau de raffinement sur les nouvelles données pour fournir des pseudo-étiquettes cohérentes avec la tâche de segmentation souhaitée, permettant d’entraîner un réseau classique sur ces nouvelles données
The New Titan Planetary Climate Model. II. Titan’s Haze and Cloud Cycles
No full textInternational audienceObservations of Titan have long revealed the presence of seasonal cycles, including haze, clouds, and gases. The lack of information on the different processes that govern these cycles prevents us from understanding all the phenomena taking place in Titan’s atmosphere. In this work, we survey Titan’s cycles exhaustively to understand their mechanisms, in particular the haze and cloud cycles that govern a large part of Titan’s climate and its surface. The Titan Planetary Climate Model (Titan PCM)—an upgraded version of the IPSL Titan Global Climate Model—incorporates a microphysical model for haze and clouds, along with a methane cycle (evaporation, transportation, condensation, precipitation). The model also features improved radiative transfer and updated spectroscopic data on gases. The Titan PCM includes phenomena hitherto omitted from Titan 3D simulations, such as cloud nucleation and condensation. Furthermore, we have coupled microphysics with radiative transfer in order to take account of feedback from haze and clouds on the thermal structure. We find that the haze follows a seasonal cycle constrained by the pole-to-pole circulation in the stratosphere. Below, the cold regions between 30 and 90 km trigger the condensation of minor species, forming a condensate mist layer throughout the year. Methane clouds form near the surface (5–25 km), in the ascending branches of the circulation, while polar clouds form higher up (60–300 km) at the winter pole after enrichment in trace compounds. The Titan PCM now enables detailed exploration of the long-term variations in Titan’s cycles, providing insights for future observations
L'effectivité des droits de la défense devant les juridictions pénales internationales : Contribution à l'étude de la procédure internationale pénale
No full textInternational audienceParis, Pedone, 2024, préface O. de Frouville, avant-propos A. Lemasson, postface R. Nollez-Goldbach, 696 p
