The French Atlantic Littoral

There are no author-identified significant results in this report

Sea surface temperature of the coastal zones of France

Thermal gradients in French coastal zones for the period of one year were mapped in order to enable a coherent study of certain oceanic features detectable by the variations in the sea surface temperature field and their evolution in time. The phenomena examined were mesoscale thermal features in the English Channel, the Bay of Biscay, and the northwestern Mediterranean; thermal gradients generated by French estuary systems; and diurnal heating in the sea surface layer. The investigation was based on Heat Capacity Mapping Mission imagery

The French Atlantic littoral and the Massif Armoricain, part 1

The author has identified the following significant results. For interpretation of Isle of Jersey imagery, two types of taxons were defined according to their variability in time. On the whole, taxons with a similar spectral signature were opposed to those with strongly varying spectral signature. The taxon types were low diachronic variations and strong diachronic variation. Imagery interpretation was restricted to the landward part of the Fromentine area, including the sand beaches which were often difficult to spectrally separate from the barren coastal dunes in the southern part of Noirmoutier Island as well as along the Breton marsh. From 1972 to 1976, sandbanks reduced in area. Two high river discharge images showed over a two year period an identical outline for the Bilho bank to seaward, whereas upstream, the bank has receeded in the same time to a line joining Paimboeuf to Montoir. The Brillantes bank has receeded at both ends, partly due to dredging operations in the access channel to Donges harbor

Unraveling the molecular basis of subunit specificity in P pilus assembly by mass spectrometry

P pili are multisubunit fibers essential for the attachment of uropathogenic Escherichia coli to the kidney. These fibers are formed by the noncovalent assembly of six different homologous subunit types in an array that is strictly defined in terms of both the number and order of each subunit type. Assembly occurs through a mechanism termed “donor-strand exchange (DSE)” in which an N-terminal extension (Nte) of one subunit donates a β-strand to an adjacent subunit, completing its Ig fold. Despite structural determination of the different subunits, the mechanism determining specificity of subunit ordering in pilus assembly remained unclear. Here, we have used noncovalent mass spectrometry to monitor DSE between all 30 possible pairs of P pilus subunits and their Ntes. We demonstrate a striking correlation between the natural order of subunits in pili and their ability to undergo DSE in vitro. The results reveal insights into the molecular mechanism by which subunit ordering during the assembly of this complex is achieved

Sea surface temperature of the coastal zones of France

The results of an investigation to map the various thermal gradients in the coastal zones of France are presented. Paricular emphasis is given to the natural phenomena and man made thermal effluents. It is shown that a close correlation exist between wind speed direction and the offshore width of the effluent

Action of Humicola lanuginosa lipase on mixed monomolecular films of tricaprylin and polyethylene glycol stearate

The hydrolysis catalyzed by Humicola lanuginosa lipase (HLL) of pure tricaprylin (TC) or stearate of polyethylene glycol 1500 (PEG-St) as well as their mixtures spread as monomolecular films were studied. The catalytic transformation of the two substrates TC or PEG-St into their respective reaction products was detected by measuring simultaneously the decrease in the film area and the surface potential using the "zero order" trough at constant surface pressure. A kinetic model describing the enzymatic hydrolysis was developed. The surface concentrations of the two substrates and their respective reaction products as well as the values of the global kinetic constants of hydrolysis were determined. The experimentally obtained global kinetic constants of the catalytic action of HLL against TC and PEG-St present in mixed monolayers of TC/PEG-St are approximately the same as in the case of pure monolayers. These obtained results give some indications that the activity of enzyme is not significantly affected by the different molecular environments in the mixed monolayers

Many-body physics of a quantum fluid of exciton-polaritons in a semiconductor microcavity

Some recent results concerning nonlinear optics in semiconductor microcavities are reviewed from the point of view of the many-body physics of an interacting photon gas. Analogies with systems of cold atoms at thermal equilibrium are drawn, and the peculiar behaviours due to the non-equilibrium regime pointed out. The richness of the predicted behaviours shows the potentialities of optical systems for the study of the physics of quantum fluids.Comment: Proceedings of QFS2006 conference to appear on JLT

The structure of the PapD-PapGII pilin complex reveals an open and flexible P5 pocket

P pili are hairlike polymeric structures that mediate binding of uropathogenic Escherichia coli to the surface of the kidney via the PapG adhesin at their tips. PapG is composed of two domains: a lectin domain at the tip of the pilus followed by a pilin domain that comprises the initial polymerizing subunit of the 1,000-plus-subunit heteropolymeric pilus fiber. Prior to assembly, periplasmic pilin domains bind to a chaperone, PapD. PapD mediates donor strand complementation, in which a beta strand of PapD temporarily completes the pilin domain's fold, preventing premature, nonproductive interactions with other pilin subunits and facilitating subunit folding. Chaperone-subunit complexes are delivered to the outer membrane usher where donor strand exchange (DSE) replaces PapD's donated beta strand with an amino-terminal extension on the next incoming pilin subunit. This occurs via a zip-in-zip-out mechanism that initiates at a relatively accessible hydrophobic space termed the P5 pocket on the terminally incorporated pilus subunit. Here, we solve the structure of PapD in complex with the pilin domain of isoform II of PapG (PapGIIp). Our data revealed that PapGIIp adopts an immunoglobulin fold with a missing seventh strand, complemented in parallel by the G1 PapD strand, typical of pilin subunits. Comparisons with other chaperone-pilin complexes indicated that the interactive surfaces are highly conserved. Interestingly, the PapGIIp P5 pocket was in an open conformation, which, as molecular dynamics simulations revealed, switches between an open and a closed conformation due to the flexibility of the surrounding loops. Our study reveals the structural details of the DSE mechanism

La estrategia Educativa 2020 o las limitaciones del Banco Mundial para promover el "aprendizaje para todos"

La nueva Estrategia Educativa 2020 del Banco Mundial establece las prioridades de reforma educativa en paises en vias de desarrollo para la decada siguiente. El titulo explicito de la estrategia, Aprendizaje para Todos, es un claro reconocimiento de que, mas alla de politicas centradas en el acceso, se debe hacer algo mas para asegurar que la educacion derive en experiencias positivas de aprendizaje. Sin embargo, como este articulo sostiene, las opciones de politicas explicitas y latentes en la Estrategia 2020 no son las mas adecuadas para lograr el Aprendizaje para Todos. El articulo desarrolla tres tipos de argumentos al respecto. El primero se refiere al fuerte apego del Banco a un conocimiento disciplinario y un enfoque metodológico que es insufi ciente para entender lo que aprenden los niños en la escuela y por que. El segundo argumento se refiere al sesgo pro-mercado de la Estrategia por lo que respecta a la reforma del sector publico y a nuevas formas de oferta educativa. En tercer lugar, el articulo senala las principales ausencias de la Estrategia, con especial atencion a las omisiones relacionadas con la compleja relación entre educación y pobreza.The World Bank's 2020 Education Strategy establishes the new education priorities in developing countries for the next decade. Its title, Learning for All, clearly recognizes that, beyond policies focusing on access, something else must be done to ensure that schooling involves positive learning experiences. However, as this paper argues, the 2020 Strategy explicit and latent policy options might not be adequate to achieve Learning for All. This paper develops three arguments on that matter. The fi rst one refers to the Bank's strong attachment to a disciplinary knowledge and a methodological approach that do not suffi ce to understand what children learn at school and why. The second one addresses its pro-market bias when it approaches the public sector reforms and the new forms of providing education. The last argument points out the main omissions of this Strategy, especially in what regards the complex relation between education and poverty