Centered-potential regularization for the advection upstream splitting method

International audienceThis paper is devoted to a centered IMEX scheme in a multidimensional framework for a wide class of multicomponent and isentropic flows. The proposed strategy is based on a regularized model where the advection velocity is modified by the gradient of the potential of the conservative forces in both mass and momentum equations. The stability of the scheme is ensured by the dissipation of mechanic energy, which stands for a mathematical entropy, under an advective CFL condition. The main physical properties, such as positivity, conservation of the total momentum, and conservation of the steady state at rest, are satisfied. In addition, asymptotic preserving properties in the regimes (“incompressible” and “acoustic”) are analyzed. Finally, several simulations are presented to illustrate our results in a simplified context of oceanic flows in one dimension

Nuclear star formation on 100 parsec scales: 10" resolution radio continuum, HI and CO observations

A program of radio line and continuum studies of star formation in nearby spiral galaxies is reported. The objective is a search for hot gas and peculiar dynamics in spiral nuclei with 10" to 30" angular resolution. Vigorous star formation is found to be a common phenomenon in the inner kpc of spirals. Arcsecond resolution observations of radio continuum emission at 6 and 2 cm were used to separate the thermal and nonthermal radio components. It was found that thermal and nonthermal emission are well mixed even on sizescales of 10 pc. To understand the reason for the increased level of star formation activity in spiral nuclei, HI and CO emission in these galaxies is studied. The CO transition was detected in M51, M82, NGC 253, NGC 6946 and IC 342 with T sub a approx. 0.5 to 2.0 K, at 20" angular resolution. The dynamics and spatial distribution of nuclear gas are being studied using VLA HI maps with 30" synthesized beams. Evidence for noncircular motions in HI was found in the nucleus of IC 342

Dwarna : a blockchain solution for dynamic consent in biobanking

Dynamic consent aims to empower research partners and facilitate active participation in the research process. Used within the context of biobanking, it gives individuals access to information and control to determine how and where their biospecimens and data should be used. We present Dwarna—a web portal for ‘dynamic consent’ that acts as a hub connecting the different stakeholders of the Malta Biobank: biobank managers, researchers, research partners, and the general public. The portal stores research partners’ consent in a blockchain to create an immutable audit trail of research partners’ consent changes. Dwarna’s structure also presents a solution to the European Union’s General Data Protection Regulation’s right to erasure—a right that is seemingly incompatible with the blockchain model. Dwarna’s transparent structure increases trustworthiness in the biobanking process by giving research partners more control over which research studies they participate in, by facilitating the withdrawal of consent and by making it possible to request that the biospecimen and associated data are destroyed.peer-reviewe

Introduction of a more automated environment in En-Route Air Traffic Control : Evaluation of impact generated on the operator by mental workload assessment

International audienceThis article deals with the introduction of partial automation in the En-Route air traffic control working position. More precisely, it presents an experiment whose objective is to evaluate the generated impact on air traffic controllers by the use of a more automated environment, including a conflict aid services system (conflict detector and solver). This impact is evaluated through the assessment of air traffic controllers' mental workload. In this experiment, the evaluation of mental workload is carried out mainly through psychophysiological parameters, especially ocular data. This assessment is compared with subjective evaluation collected by questionnaire and assessment scale, and also with performance indicators analysis focused on communications between controllers and pilots. Results achieved show that automated system proposed in the case of the SESAR project (W.P.4.7.2) seems to be promising because it generates a decrease of mental workload felt in comparison with a non-automated situation

Numerical scheme for multilayer shallow-water model in the low-Froude number regime

International audienceThe aim of this note is to present a multi-dimensional numerical scheme approximating the solutions of the multilayer shallow water model in the low Froude number regime. The proposed strategy is based on a regularized model where the advection velocity is modified with a pressure gradient in both mass and momentum equations. The numerical solution satisfy the dissipation of energy, which act for mathematical entropy, and the main physical properties required for simulations within oceanic flows. Résumé Schéma numérique pour lesmo eles de Saint-Venant multi-couchè a faible nombre de Froude. Le but de cette note est de présenter un schéma numérique multi-dimensionnel rapprochant les solutions dumo ele de Saint-Venant multi-couche en régime de faible nombre de Froude. La stratégie proposée est basée sur unmo ele régulariséò u la vitesse de transport est modifié par un gradient de pression dans le equations de la masse et de la quantité de mouvement. La solution numérique satisfait la dissipation denergie,jouantlerôledel'entropiedupointdevuemathématique,etlesprincipalespropriétésphysiquesnécessairesauxsimulationsdanslecadredeecoulementsocéanique

Beltanelliformis brunsae Menner in Keller et al., 1974: an undoubted Ediacaran fossil from Neoproterozoic of Dobrogea (Romania)

International audienceEdiacaran fossils are now largely known in different parts of the world. However, some countries are poorly documented on these remains of a still enigmatic life. Thus, rare fossils from the Neoproterozoic Histria Formation of central Dobrogea (Romania) have been reported. Two specimens with discoid imprints are described here in detail and assigned to the typical Ediacaran species Beltanelliformis brunsae Menner in Keller et al., 1974. This paleontological development confirms both the large geographical distribution of this species and the Ediacaran age of the Histria Formation. KEY WORDS Flat discoid imprints, Ediacaran biota, Precambrian, Dobrogea, Romania. RÉSUMÉLes fossiles édiacariens sont maintenant largement connus à travers le monde. Cepednant, certaines régions restent peu documentées sur ces restes, témoignages d’une vie qui apparaît encore aujourd’hui assez énigmatique. Ainsi, seuls de rares fossiles provenant de la Formation Histria du Néoprotérozoïque de Dobrogea centrale (Roumanie) avaient été signalés. Deux échantillons portant des impressions discoïdes sont ici décrits en détail et attribués à l’espèce typiquement édiacarienne Beltanelliformis brunsae Menner in Keller et al., 1974. Cette identification permet de confirmer la large répartition de cette espèce et l’âge édiacarien de la Formation Histria

Three-dimensional dynamic rupture simulation with a high-order discontinuous Galerkin method on unstructured tetrahedral meshes

Accurate and efficient numerical methods to simulate dynamic earthquake rupture and wave propagation in complex media and complex fault geometries are needed to address fundamental questions in earthquake dynamics, to integrate seismic and geodetic data into emerging approaches for dynamic source inversion, and to generate realistic physics-based earthquake scenarios for hazard assessment. Modeling of spontaneous earthquake rupture and seismic wave propagation by a high-order discontinuous Galerkin (DG) method combined with an arbitrarily high-order derivatives (ADER) time integration method was introduced in two dimensions by de la Puente et al. (2009). The ADER-DG method enables high accuracy in space and time and discretization by unstructured meshes. Here we extend this method to three-dimensional dynamic rupture problems. The high geometrical flexibility provided by the usage of tetrahedral elements and the lack of spurious mesh reflections in the ADER-DG method allows the refinement of the mesh close to the fault to model the rupture dynamics adequately while concentrating computational resources only where needed. Moreover, ADER-DG does not generate spurious high-frequency perturbations on the fault and hence does not require artificial Kelvin-Voigt damping. We verify our three-dimensional implementation by comparing results of the SCEC TPV3 test problem with two well-established numerical methods, finite differences, and spectral boundary integral. Furthermore, a convergence study is presented to demonstrate the systematic consistency of the method. To illustrate the capabilities of the high-order accurate ADER-DG scheme on unstructured meshes, we simulate an earthquake scenario, inspired by the 1992 Landers earthquake, that includes curved faults, fault branches, and surface topography