Velocity-informed upper bounds on the convective heat transport induced by internal heat sources and sinks

Three-dimensional convection driven by internal heat sources and sinks (CISS) leads to experimental and numerical scaling-laws compatible with a mixing-length - or `ultimate' - scaling regime $Nu \sim \sqrt{Ra}$. However, asymptotic analytic solutions and idealized 2D simulations have shown that laminar flow solutions can transport heat even more efficiently, with $Nu \sim Ra$. The turbulent nature of the flow thus has a profound impact on its transport properties. In the present contribution we give this statement a precise mathematical sense. We show that the Nusselt number maximized over all solutions is bounded from above by const.$\times Ra$, before restricting attention to 'fully turbulent branches of solutions', defined as families of solutions characterized by a finite nonzero limit of the dissipation coefficient at large driving amplitude. Maximization of $Nu$ over such branches of solutions yields the better upper-bound $Nu \lesssim \sqrt{Ra}$. We then provide 3D numerical and experimental data of CISS compatible with a finite limiting value of the dissipation coefficient at large driving amplitude. It thus seems that CISS achieves the maximal heat transport scaling over fully turbulent solutions

A Fast Method To Predict Protein Interaction Sites From Sequences

A simple method for predicting residues involved in protein interaction sites is proposed. In the absence of any structural report, the procedure identifies linear stretches of sequences as "receptor-binding domains" (RBDs) by analysing hydrophobicity distribution. The sequences of two databases of non-homologous interaction sites eliciting various biological activities were tested; 59-80 % were detected as RBDs. A statistical analysis of amino acid frequencies was carried out in known interaction sites and in predicted RBDs. RBDs were predicted from the 80,000 sequences of the Swissprot database. In both cases, arginine is the most frequently occurring residue. The RBD procedure can also detect residues involved in specific interaction sites such as the DNA-binding (95 % detected) and Ca-binding domains (83 % detected). We report two recent analyses; from the prediction of RBDs in sequences to the experimental demonstration of the functional activities. The examples concern a retroviral Gag protein and a penicillin-binding protein. We support that this method is a quick way to predict protein interaction sites from sequences and is helpful for guiding experiments such as site-specific mutageneses, two-hybrid systems or the synthesis of inhibitors

PDM system implementation based on UML

International audienceThe paper deals with a Unified Modeling Language (UML)-based approach for implementing Product Data Management (PDM) system. Such kind of system enables the management of the entire product lifecycle and related information about its design, its manufacturing and its in-service.The interest of using an UML-based approach for modeling, specifying and implementing PDM systems is detailed. Then an implementation method is proposed in order to clarify the instantiation of UML diagrams into database entities. Regarding a business case study based on the needs of a turboprop aircraft development project, the preliminary implementation of PDM system is presented. The used UML diagrams for the modeling and integration of product, process, and resource data is detailed in order to argue the interest of an object-oriented approach in such kind of PDM implementation

Towards digital engineering : collaborative management of design, analysis and manufacturing data

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Nietzsche et le divin

Ce huitième numéro de la revue Le Portique se compose pour l’essentiel de la publication des actes du colloque Nietzsche qui a eu lieu à l’Université de Metz en septembre 2000. Il constitue donc un numéro exceptionnel qui, de ce fait, ne comporte pas de recensions

Atteindre l'histoire de la forêt de Compiègne par la télédétection aérienne et l'exploration des archives du sol

International audienceArchaeological research in the forest environment has undergone significant development over the last decade, mainly because of the growing use of airborne laser survey techniques, better known by the acronym LiDAR (Light Detection And Ranging). These techniques, implemented in many forests , have breathed new life into the scientific issues, while generating new synergies between research actors. The article offers a concrete illustration relating to the Forest of Compiègne.La recherche archéologique en milieu forestier connaît un important dévelop-pement depuis une dizaine d'années, en raison notamment de l'utilisation croissante des techniques de levé par laser aéroporté, plus connues sous l'acronyme de LiDAR (light detection and ranging). Ces techniques, mises en oeuvre dans de nombreuses forêts, ont considérablement renouvelé les problématiques scientifiques, tout en générant de nou-velles synergies entre les acteurs de la recherche. L'article en propose une illustration concrète portant sur la forêt de Compiègne

Lands afforested since millenia store more carbon in the soil

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Combined synchrotron- and electron microscopy-based imaging to decipher silver nanoparticle fate in hepatic models

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Impairment of hepatocyte nuclear receptors upon silver nanoparticle exposure: an imaging-guided study

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