Laboratory PIV Measurements of Wave Breaking on Beach

ISBN 1-880653-62-1Experiment were conducted in the ESIM wave tank in Marseilles in order to study the space/time evolution of the flow field under waves breaking on an 1/15 beach slope. Fluid particles velocities were measured at different depths, before, during and after the breaking event using the Particle Imaging Velocimetry (PIV) technique. The mean and fluctuant components of the flow were calculated

Predicting the results of the REF using departmental h-index: A look at biology, chemistry, physics, and sociology.

Can metrics be used instead of peer review for REF-type assessments? With the stakes so high, any replacement would have to be extremely accurate. Olesya Mryglod, Ralph Kenna, Yurij Holovatch and Bertrand Berche looked at two metric candidates, including the departmental h-index, and four subject areas: biology, chemistry, physics and sociology. The correlations are significant, but comparisons with RAE indicate that while the departmental h-index is the best metric, it would not have been good enough to replace the peer review exercise. A more important question is whether we should seek to measure research quality using metrics at all

Liens conceptuels et relations sémantiques : proposition de représentation des connaissances en sciences du langage.

Le travail que nous présentons s'intègre dans un projet de production d'une ressource destinée à représenter les connaissances en sciences du langage et à annoter sémantiquement des documents en texte intégral. Il consiste à ce stade de démarrage du projet en un examen des relations entre les liens conceptuels et les relations sémantiques qui organisent un thesaurus afin de prévoir une amélioration de sa structure et conduire à une représentation plus cohérente du domaine

Observing Exoplanets with High-Dispersion Coronagraphy. II. Demonstration of an Active Single-Mode Fiber Injection Unit

High-dispersion coronagraphy (HDC) optimally combines high contrast imaging techniques such as adaptive optics/wavefront control plus coronagraphy to high spectral resolution spectroscopy. HDC is a critical pathway towards fully characterizing exoplanet atmospheres across a broad range of masses from giant gaseous planets down to Earth-like planets. In addition to determining the molecular composition of exoplanet atmospheres, HDC also enables Doppler mapping of atmosphere inhomogeneities (temperature, clouds, wind), as well as precise measurements of exoplanet rotational velocities. Here, we demonstrate an innovative concept for injecting the directly-imaged planet light into a single-mode fiber, linking a high-contrast adaptively-corrected coronagraph to a high-resolution spectrograph (diffraction-limited or not). Our laboratory demonstration includes three key milestones: close-to-theoretical injection efficiency, accurate pointing and tracking, on-fiber coherent modulation and speckle nulling of spurious starlight signal coupling into the fiber. Using the extreme modal selectivity of single-mode fibers, we also demonstrated speckle suppression gains that outperform conventional image-based speckle nulling by at least two orders of magnitude.Comment: 10 pages, 7 figures, accepted by Ap

Homotopical and Higher Categorical Structures in Algebraic Geometry

This a slightly expended version of my habilitation thesis, which is an overview of my research activities during the last 4 years, written in a rather informal style.Comment: Habilitation thesis, 93 pages. Some misprints corrected and remarks adde