Caractérisation statique et dynamique des voyelles dans des séquences VV

International audienceStatic and dynamic characterization of vowels in VV sequences. The present study aims at evaluating the respective contributions of static and dynamic cues to vowel classification. Formant cues from six french vowels and sixteen V1V2 slope transitions were extracted in order to investigate the respective contributions of dynamic and static cues that would be respectively related to transitions or center frequencies. The corresponding data were collected from a dedicated task in which speech rate was influenced experimentally in order to trigger potential variations of rate of change within the transitions. The current results do not favour any of the two potential accounts but show that dynamic cues may be as reliable as static ones. Follow-ups to this protocol are offered that may contribute to this issue more informatively.Nous étudions les indices acoustiques liés à la caractérisation statique et / ou dynamique des voyelles du français. Nous avons analysé les caractéristiques formantiques de six réalisations vocaliques ainsi que les transitions formantiques de seize combinaisons V1V2 impliquant ces 6 voyelles afin d'évaluer les contributions des indices dynamiques liés aux transitions entre voyelles et des indices statiques de fréquence. Les mesures correspondantes sont issues d'un protocole dans lequel le débit de parole était influencé expérimentalement afin de provoquer d'éventuelles variations de vitesse de transition. Les résultats ne permettent pas de départager ces deux hypothèses mais montrent que les indices dynamiques pourraient être aussi fiables que les mesures statiques. Des pistes d'extension de ce travail sont proposées qui pourraient contribuer de manière plus informative à cette problématique

Applications of a high-order algorithm for LES and CAA in complex geometries

In confined flows, non-linear interactions between acoustics and aerodynamics produce high pressure levels. To tackle these couplings, a numerical tool is developed: Code_Safari. It is based on optimized high-order finite-difference schemes in conjunction with optimized filters on a multi-domain approach. A shock-capturing filter is also applied. Code_Safari is validated on classical test problems and used for realistic applications (ducted cavity, sudden enlargement, rod-airfoil interaction)

Small body harvest with the Antarctic Search for Transiting Exoplanets (ASTEP) project

Small Solar system bodies serve as pristine records that have been minimally altered since their formation. Their observations provide valuable information regarding the formation and evolution of our Solar system. Interstellar objects (ISOs) can also provide insight on the formation of exoplanetary systems and planetary system evolution as a whole. In this work, we present the application of our framework to search for small Solar system bodies in exoplanet transit survey data collected by the Antarctic Search for Transiting ExoPlanets (ASTEP) project. We analysed data collected during the Austral winter of 2021 by the ASTEP 400 telescope located at the Concordia Station, at Dome C, Antarctica. We identified 20 known objects from dynamical classes ranging from Inner Main-belt asteroids to one comet. Our search recovered known objects down to a magnitude of $V$ = 20.4 mag, with a retrieval rate of $\sim$80% for objects with $V \le$ 20 mag. Future work will apply the pipeline to archival ASTEP data that observed fields for periods of longer than a few hours to treat them as deep-drilling datasets and reach fainter limiting magnitudes for slow-moving objects, on the order of $V\approx$ 23-24 mag.Comment: Accepted for publication in MNRAS (Monthly Notices of the Royal Astronomical Society), 9 pages, 8 figure

Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments

Comprehending and predicting the way humans affect the Earth's Critical Zone remains a challenge. An understanding of the past changes resulting from human and non-human influences in the dynamics of the Critical Zone is crucial. Here, we use a retrospective approach to address this question based on a new lithium (Li) isotope record from the Late Glacial Period to the present from a pre-Alpine lake sediment sequence (Lake La Thuile, France). Coupled with the lake sediment archive, the investigation of present-day soils in the lake catchment suggests that lake sediments are not necessarily recording the erosoin of topsoil in the catchment. Our findings indicate that soil particles can be sorted during transportation to the lake, with finer particles being preferentially mobilized, highlighting the influence of fine particle transport on the Li isotope signature of soils and lake sediments. Characterized by low Li isotope signatures, changes in weathering signatures in lake sediments can be amplified by the combined effect of soil development and selective transport. In the La Thuile catchment, soil development was limited during the Late Glacial Period, whereas it became a dominant process during the Holocene climatic optimum together with enhanced selective transport of fine particles. Human activities since 3,000–4,000 yr cal BP induced a strong perturbation hindering both soil formation and selective transport by reinforcing erosion rates. After a period of topsoil destruction caused by intense deforestation and agriculture, lake Li isotopes record the evolution of soil profiles associated with changes in agricultural practices

Transiting Exoplanet Studies and Community Targets for JWST's Early Release Science Program

The James Webb Space Telescope will revolutionize transiting exoplanet atmospheric science due to its capability for continuous, long-duration observations and its larger collecting area, spectral coverage, and spectral resolution compared to existing space-based facilities. However, it is unclear precisely how well JWST will perform and which of its myriad instruments and observing modes will be best suited for transiting exoplanet studies. In this article, we describe a prefatory JWST Early Release Science (ERS) program that focuses on testing specific observing modes to quickly give the community the data and experience it needs to plan more efficient and successful future transiting exoplanet characterization programs. We propose a multi-pronged approach wherein one aspect of the program focuses on observing transits of a single target with all of the recommended observing modes to identify and understand potential systematics, compare transmission spectra at overlapping and neighboring wavelength regions, confirm throughputs, and determine overall performances. In our search for transiting exoplanets that are well suited to achieving these goals, we identify 12 objects (dubbed "community targets") that meet our defined criteria. Currently, the most favorable target is WASP-62b because of its large predicted signal size, relatively bright host star, and location in JWST's continuous viewing zone. Since most of the community targets do not have well-characterized atmospheres, we recommend initiating preparatory observing programs to determine the presence of obscuring clouds/hazes within their atmospheres. Measurable spectroscopic features are needed to establish the optimal resolution and wavelength regions for exoplanet characterization. Other initiatives from our proposed ERS program include testing the instrument brightness limits and performing phase-curve observations.(Abridged)Comment: This is a white paper that originated from an open discussion at the Enabling Transiting Exoplanet Science with JWST workshop held November 16 - 18, 2015 at STScI (http://www.stsci.edu/jwst/science/exoplanets). Accepted for publication in PAS

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Intérêt de la radioembolisation dans le carcinome Hépatocellulaire avec thrombose vasculaire (comparaison rétrospective avec le Sorafenib)

Introduction: La thrombose vasculaire est un facteur de mauvais pronostic majeur dans le Carcinome Hépatocellulaire (CHC). L'efficacité du sorafenib est limitée. La radioembolisation semble une option intéressante. Patients et Méthodes: Nous avons comparé rétrospectivement les patients traités à Rennes, Bordeaux et Marseille pour un CHC avec thrombose vasculaire macroscopique. Nous avons comparé les patients traités par radioembolisation ou sorafenib. Résultats: 201 patients ont été traités: 20 par radioembolisation seule, 14 par radioembolisation et sorafenib et 167 par sorafenib seul. Les réponses mRECIST et de la thrombose étaient meilleures dans le groupe radioembolisation. La survie globale médiane était de 18,3 mois dans le groupe radioembolisation contre 5,9 mois pour le sorafenib (p<0,001). La différence persistait en analyse multivariée. Les temps jusqu'à progression médians était respectivement de 6,9 mois contre 4,1 mois (p=0,031). Conclusion: La radioembolisation semble une option plus intéressante que le sorafenib chez les patients présentant un CHC avec thrombose vasculaire.RENNES1-BU Santé (352382103) / SudocSudocFranceF