381 research outputs found

    Eugène Péquignot : témoin jurassien de la réorganisation économique mondiale

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    Du 10 avril au 19 mai 1922, trente-quatre nations européennes se réunissent à Gênes pour tenter de contenir une crise financière, économique et monétaire sans précédents. Elles échafaudent le système d'échange monétaire international qui perdure aujourd'hui au travers du Fonds monétaire international (FMI) et de la Banque mondiale

    Cavitation-induced force transition in confined viscous liquids under traction

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    We perform traction experiments on simple liquids highly confined between parallel plates. At small separation rates, we observe a simple response corresponding to a convergent Poiseuille flow. Dramatic changes in the force response occur at high separation rates, with the appearance of a force plateau followed by an abrupt drop. By direct observation in the course of the experiment, we show that cavitation accounts for these features which are reminiscent of the utmost complex behavior of adhesive films under traction. Surprisingly enough, this is observed here in purely viscous fluids.Comment: Submitted to Physical Review Letters on May 31, 2002. Related informations on http://www.crpp.u-bordeaux.fr/tack.htm

    Retrieval of tropospheric CO column from hyperspectral infrared sounders - application to four years of Aqua/AIRS and MetOp-A/IASI

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    International audienceFour years of tropospheric integrated content of CO were retrieved from infrared hyperspectral observations of AIRS onboard Aqua and IASI onboard MetOp-A, for the period July 2007-June 2011. The retrieval method is based on a double differential approach that relies on the difference between brightness temperatures observed by the sounder and BT simulated by the Automatised Atmospheric Absorption Atlas (4A) radiative transfer model on colocated ECMWF reanalyses, for several couples of channels located in the 4.67 mu m CO band. AIRS and IASI give access to similar integrated contents of CO with a maximum sensitivity near 450 hPa and a half-height width of the weighting function between 200 and 750 hPa depending on the thermal contrast (i.e., the difference between the surface temperature and the temperature of the first pressure level). However, differences in their spectral and radiometric characteristics yield differences in the retrieval characteristics with AIRS selected couples of channels being more sensitive to surface characteristics. Moreover, IASI covers the whole CO absorption band, with a 3 times better spectral resolution, giving access to channels presenting a 3 times higher signal to noise ratio. This results in a better precision and lower standard deviation of the IASI retrievals. Conservatively, comparisons with CARIBIC aircraft measurements yield an averaged relative difference of 3.4% for IASI and 4.9% for AIRS. On average, AIRS and IASI retrievals are in very good agreement, showing the same seasonality, seasonal amplitudes, interannual variability and spatial distribution. The analysis of the monthly evolution of CO particularly highlights the expected strong influence of biomass burning on the evolution of CO in several tropical regions. In particular, a sharp increase in CO in 2010 in the southern tropics, especially over South America and South Africa, is observed, and is shown to be related to El Nino and to the Atlantic Multidecadal Oscillation

    Closing the medullary canal after retrograde nail removal using a bioabsorbable bone plug: technical tip

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    We describe a simple technique for closure of the intra-articular opening after the removal of a retrograde femur nail. With the use of a gelatine bioabsorbable bone plug the medullary canal is closed, reducing leakage of blood and cancellous bone particles from the bone into the knee joint

    Nematic-Wetted Colloids in the Isotropic Phase: Pairwise Interaction, Biaxiality and Defects

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    We calculate the interaction between two spherical colloidal particles embedded in the isotropic phase of a nematogenic liquid. The surface of the particles induces wetting nematic coronas that mediate an elastic interaction. In the weak wetting regime, we obtain exact results for the interaction energy and the texture, showing that defects and biaxiality arise, although they are not topologically required. We evidence rich behaviors, including the possibility of reversible colloidal aggregation and dispersion. Complex anisotropic self-assembled phases might be formed in dense suspensions.Comment: 4 pages, 6 figure

    Is a 3-mm intrafractional margin sufficient for daily image-guided intensity-modulated radiation therapy of prostate cancer?

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    PURPOSE: To determine whether a 3-mm isotropic target margin adequately covers the prostate and seminal vesicles (SVs) during administration of an intensity-modulated radiation therapy (IMRT) treatment fraction, assuming that daily image-guided setup is performed just before each fraction. MATERIALS AND METHODS: In-room computed tomographic (CT) scans were acquired immediately before and after a daily treatment fraction in 46 patients with prostate cancer. An eight-field IMRT plan was designed using the pre-fraction CT with a 3-mm margin and subsequently recalculated on the post-fraction CT. For convenience of comparison, dose plans were scaled to full course of treatment (75.6 Gy). Dose coverage was assessed on the post-treatment CT image set. RESULTS: During one treatment fraction (21.4+/-5.5 min), there were reductions in the volumes of the prostate and SVs receiving the prescribed dose (median reduction 0.1% and 1.0%, respectively, p\u3c0.001) and in the minimum dose to 0.1 cm(3) of their volumes (median reduction 0.5 and 1.5 Gy, p\u3c0.001). Of the 46 patients, three patients\u27 prostates and eight patients\u27 SVs did not maintain dose coverage above 70 Gy. Rectal filling correlated with decreased percentage-volume of SV receiving 75.6, 70, and 60 Gy (p\u3c0.02). CONCLUSIONS: The 3-mm intrafractional margin was adequate for prostate dose coverage. However, a significant subset of patients lost SV dose coverage. The rectal volume change significantly affected SV dose coverage. For advanced-stage prostate cancers, we recommend to use larger margins or improve organ immobilization (such as with a rectal balloon) to ensure SV coverage
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