Coccolithophore blooms in the Bay of Biscay: Results from the PEACE project

Conference (2013, May 15)

Pelagic and benthic processes were determined in the nothern Bay of Biscay when coccolithophores blooms occured between 2006 and 2008. Here we present a synthesis of pelagic primary production ... [more ▼]

Pelagic and benthic processes were determined in the nothern Bay of Biscay when coccolithophores blooms occured between 2006 and 2008. Here we present a synthesis of pelagic primary production, calcification and respiration and benthic respiration and dissolution of CaCO3. Or results suggest that CaCO3 dissolution in the surface sediments is small (~1%) compared to integrated pelagic calcification. Benthic respiration increases with the organic load of the sediment and represents ~8% of the integrated pelagic respiration. The relationship between dissolution and respiration rates suggests a metabolic driven dissolution in waters supersaturated with respect to calcite (omega>3.5). We address a mass balance of the described processes and associated CO2 fluxes in the water column. [less ▲]

A basal thunnosaurian from Iraq reveals disparate phylogenetic origins for Cretaceous ichthyosaurs

in Biology Letters (2013), 9(20130021), 1-6

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a ... [more ▼]

Cretaceous ichthyosaurs have typically been considered a small, homogeneous assemblage sharing a common Late Jurassic ancestor. Their low diversity and disparity have been interpreted as indicative of a decline leading to their Cenomanian extinction. We describe the first post-Triassic ichthyosaur from the Middle East, Malawania anachronus gen. et sp. nov. from the Early Cretaceous of Iraq, and re-evaluate the evolutionary history of parvipelvian ichthyosaurs via phylogenetic and cladogenesis rate analyses. Malawania represents a basal grade in thunnosaurian evolution that arose during a major Late Triassic radiation event and was previously thought to have gone extinct during the Early Jurassic. Its pectoral morphology appears surprisingly archaic, retaining a forefin architecture similar to that of its Early Jurassic relatives. After the initial latest Triassic radiation of early thunnosaurians, two subsequent large radiations produced lineages with Cretaceous representatives, but the radiation events themselves are pre-Cretaceous. Cretaceous ichthyosaurs therefore include distantly related lineages, with contrasting evolutionary histories, and appear more diverse and disparate than previously supposed. [less ▲]

Matériaux et systèmes constructifs: critères de sélection

Conference given outside the academic context (2013)

Donner quelques idées sur les raisons qui amènent l'ingénieur à baser son choix des matériaux sur des critères autres que techniques

Méthode d'entrevue d'investigation non-suggestive en contexte clinique: questions éthiques d'usage et de mésusage. (symposium)

Conference (2013, May 15)

La méthode d’entrevue d’investigation non suggestive inspirée de celle du NICHD a été proposée aux équipes SOS Enfants depuis deux ans, dans le cadre d’un partenariat avec Le Centre d’Expertise Marie ... [more ▼]

La méthode d’entrevue d’investigation non suggestive inspirée de celle du NICHD a été proposée aux équipes SOS Enfants depuis deux ans, dans le cadre d’un partenariat avec Le Centre d’Expertise Marie-Vincent. Six intervenants issus de 3 équipes ont été sensibilisés à cette pratique. Depuis, chacun a poursuivi son application. Le fonctionnement de chacune des équipes dépend fortement de l’arrondissement judiciaire dans lequel elles se situent tant du point de vue des mentalités que de la population et de son contexte (rural, urbain, etc.). Ainsi, certaines équipes n’interviennent que très rarement en première ligne, à l’opposé d’autres, qui font exclusivement de l’évaluation. Ces différences de contextes amènent diverses réflexions et utilisations de l’outil dans la rencontre avec un enfant présumé ou victime d’abus sexuels. Ce sont ces réflexions cliniques et le cheminement de nos échanges que nous souhaitons partager pendant le symposium. Les apports de l’outil ont été souvent discutés, nous ne reprendrons pour notre part que ceux spécifiques à notre pratique clinique au sein du secteur SOS-enfants. Les réflexions qui nous animent et que nous souhaitons discuter sont les suivantes :  -Les entretiens du NICHD sont riches sur le plan de la clinique. Les faits investigués et les détails amenés par la victime présumée nous renseignent sur les mécanismes de défense utilisés, sur les capacités de résilience et aident l’intervenant à repérer ce qui a fait trauma. - Une certaine liberté quant au protocole peut être prise par les intervenants dans le cadre clinique, se pose alors des questions éthiques notamment en cas de saisies judiciaires. - Une telle méthode ne devrait-elle pas être connue par tout intervenant concerné par la problématique de la maltraitance. - La méthode doit-elle s’adresser à la maltraitance physique également ? - Pourrait-elle être utilisée autant avec les victimes qu’avec les auteurs, les enfants que les ado et les adultes? - Faut-il garder le même intervenant après l’entrevue pour la poursuite de l’évaluation et/ou traitement ? - Qu’en est-il de la question du non verbal ? - La méthode doit-elle être utilisée de manière systématique et qu’entend-on par systématique ? [less ▲]

Virtual Leodium: Development of an archaeological information system, a case study on an historical 3D city scale model

Conference (2013, May 14)

Virtual Leodium is an interdisciplinary project aiming to develop an archaeological information system based on a city scale model. This paper addresses the workflow of the project. We present the current ... [more ▼]

Virtual Leodium is an interdisciplinary project aiming to develop an archaeological information system based on a city scale model. This paper addresses the workflow of the project. We present the current prototype of the Archaeological Information System and the new urban archaeological model under development. [less ▲]

Des quartiers durables en Wallonie. Etat d'avancement des travaux relatifs à l'évaluation des projets de quartiers durables.

Scientific conference (2013, May 14)

Seasonal and inter-annual variations of gross primary production, community respiration, and net community production of a seagrass meadow

Conference (2013, May 13)

MEASURING VARIABILITY SOURCES IN NMR METABOLOMIC STUDIES

Conference (2013, May 13)

Due to the huge amount of information available in NMR spectra obtained from the analysis of metabolomic experiments, multivariate analysis such as Principal Component Analysis (PCA) are required to ... [more ▼]

Due to the huge amount of information available in NMR spectra obtained from the analysis of metabolomic experiments, multivariate analysis such as Principal Component Analysis (PCA) are required to understand the influence of treatments over the metabolites [1]. However, many experiments in metabolomics studies have more complexes variability structures than simply comparing several treatments: they may include time effects, biological effects such as diet or hormonal status, and other blocking factors or variability sources: samples stability, age of the individuals, pH of a buffer, days of acquisition, and so on. Metabolomic data analysis needs to extract from the spectral data matrix the variations linked to a change indicated in the factor of interest. However other sources of variability may impair this objective. This stresses the importance to discover the sources of variability of the spectral metabolomic data using appropriate methodology. Classically, to analyze such data analysis of variance (ANOVA) or multivariate ANOVA (MANOVA) [2] is used. However direct application of these methodologies to NMR spectra obtained from structured metabolomics studies is inappropriate or impossible. More complex data analyses methodologies are required to understand the importance of the various factors implied in the experiments and to provide a measure of their variance components. Three related methodologies have been proposed to achieve this: ASCA [3], ANOVA-PCA [4] and AComDim [5]. The ASCA and ANOVA-PCA methodologies combine first an analysis of variance step (ANOVA) and then a PCA step. The AComDim one adds to the output of the ANOVA-PCA step a multi-block analysis. In this presentation, the usefulness and applicability of these advanced techniques to data analysis of NMR metabolomic spectra are provided to highlight the increase of knowledge gained and the estimation of main sources of variability arising in an experimental setup. Two NMR databases will be used [6]. The first one concerns human serum analyzed by 1H-NMR where three random factors are present: day of measurement (3 days), sample (2 samples per individual) and replication of analyses as well as two fixed controlled factors, time of measurement after thawing (2 times) and two protein suppression methods for the spectral pre-treatment. The second database is about the 1H-NMR analyses of rats’ urine where two different concentrations of citrate and of hippurate were deliberately added and three other sources of variability are present: urine pool diluted or not diluted, repetitions of analyses, days of analyses (three days), as well as two different spectral pre-treatment procedures. [less ▲]

Design of a small-scale organic Rankine cycle engine used in a solar power plant

in International Journal of Low Carbon Technologies (2013)

Under the economic and political pressure due to the depletion of fossil fuels and global warming concerns, it is necessary to develop more sustainable techniques to provide electrical power. In this ... [more ▼]

Under the economic and political pressure due to the depletion of fossil fuels and global warming concerns, it is necessary to develop more sustainable techniques to provide electrical power. In this context, the present study aims at designing, building and testing a small-scale organic Rankine cycle (ORC) solar power plant ( 3 kWe) in order to define and optimize control strategies that could be applied to larger systems. This paper presents a first step of the design of the solar power plant and focuses more specifically on the ORC engine. This design is defined on the basis of simulation models of the ORC engine and takes into account some technical limitations such as the allowed operating ranges and the technical maturity of the components. The final configuration includes a diaphragm pump, two plate heat exchangers for the regenerator and the evaporator, an air-cooled condenser, two hermetic scroll expanders in series and R245fa as the working fluid. Simulations indicate that an efficiency close to 12% for the ORC engine can be reached for evaporating and condensing temperatures of 140 and 358C, respectively. [less ▲]

Parasitic interference in nulling interferometry

in Monthly Notices of the Royal Astronomical Society (2013), 431(2), 1286-1295

Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line of sight so that the stellar flux is rejected, while the ... [more ▼]

Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line of sight so that the stellar flux is rejected, while the flux of the off-axis source can be transmitted. In practice, various instrumental perturbations can degrade the nulling performance. Any imperfection in phase, amplitude or polarization produces a spurious flux that leaks to the interferometer output and corrupts the transmitted off-axis flux. One of these instrumental perturbations is the crosstalk phenomenon, which occurs because of multiple parasitic reflections inside transmitting optics, and/or diffraction effects related to beam propagation along finite size optics. It can include a crosstalk of a beam with itself, and a mutual crosstalk between different beams. This can create a parasitic interference pattern, which degrades the intrinsic transmission map - or intensity response - of the interferometer. In this context, we describe how this instrumental effect impairs the performance of a Bracewell interferometer. A simple formalism is developed to derive the corresponding modified intensity response of the interferometer, as a function of the two parameters of interest: the crosstalk level (or contamination rate) and the phase shift between the primary and secondary - parasitic - beams. We then apply our mathematical approach to a few scientific cases, both analytically and using the GENIESIM simulation software, adapted to handle coherent crosstalk. Our results show that a coherent crosstalk level of about 1 per cent implies a 20 per cent drop of the signal-to-noise ratio at most. Careful attention should thus be paid to reduce the crosstalk level inside an interferometric instrument and ensure an instrumental stability that provides the necessary sensitivity through calibration procedures. [less ▲]