448 research outputs found

    Analysis of the rod-drop experiments performed during the CABRI commissioning tests

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    International audienceCABRI is an experimental pulse reactor operated by the CEA at the Cadarache research center. After its refurbishment, it is now able to provide experiments in prototypical PWR conditions (155 bar, 300DC). Before operating, commissioning tests were performed, including control rod worth measurements. These experi-ments are done thanks to the rod-drop technique, which gathers static and dynamic effects. This paper reminds the theoretical background of the rod drop analysis. Then it gives a rigorous definition for the MSM factors (i.e. spatial correction factors to take into account the modification of the detector efficiency). An uncertainty analysis is performed and results prove the validity of the proposed model. Finally, the conclusion focuses on some possible improvements, like a rigorous importance calculation using the stochastic code TRIPOLI-4 and the use of different nuclear data libraries

    A comparison of the kinetics of in vitro starch digestion in smooth and wrinkled peas by porcine pancreatic alpha-amylase

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    This study describes the impact of crop genetics and processing in two pea lines (Pisum sativum L.) on starch digestion kinetics. Mutation at the rugosus (r) locus leads to wrinkled pea seeds, a reduction in starch content and a lower extent of in vitro starch digestibility. The Logarithm of Slope (LOS) kinetic model was used to analyse digestion curves obtained using porcine pancreatic α-amylase for a range of particle size fractions. Changes in starch structure induced by the r mutation led to clear differences in starch digestion kinetics for purified starches and pea flours. Larger particle size fractions showed slowed starch digestion relative to the purified starch, but significant differences still existed between r and wild type pea lines. It is expected that this work will help inform the design of future studies where both starch structure and food structure are important determinants of digestion behavior

    Biométrie de la glossine : étude statistique des mensurations de l'aile dans diverses communautés

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    Des mensurations ont été faites dans quatre lots de tsé-tsé de la même sous-espèce: Glossina fuscipes quanzensis Pires; chacun de ces lots provenait d'une localité distincte. L'on constate qu'il existe des différences significatives de la taille moyenne entre certains de ces lots. Cette différence de taille est vraisemblablement attribuable principalement à la différence des biotopes selon les lieux de captur

    A progressive refinement approach for the visualisation of implicit surfaces

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    Visualising implicit surfaces with the ray casting method is a slow procedure. The design cycle of a new implicit surface is, therefore, fraught with long latency times as a user must wait for the surface to be rendered before being able to decide what changes should be introduced in the next iteration. In this paper, we present an attempt at reducing the design cycle of an implicit surface modeler by introducing a progressive refinement rendering approach to the visualisation of implicit surfaces. This progressive refinement renderer provides a quick previewing facility. It first displays a low quality estimate of what the final rendering is going to be and, as the computation progresses, increases the quality of this estimate at a steady rate. The progressive refinement algorithm is based on the adaptive subdivision of the viewing frustrum into smaller cells. An estimate for the variation of the implicit function inside each cell is obtained with an affine arithmetic range estimation technique. Overall, we show that our progressive refinement approach not only provides the user with visual feedback as the rendering advances but is also capable of completing the image faster than a conventional implicit surface rendering algorithm based on ray casting

    Observations sur un élevage de Glossina tachinoides West., après adoption du lapin comme animal-hôte

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    L'adoption du lapin comme animal hôte et la réception d'un important lot de pupes ont permis d'obtenir, depuis le début de l'année 1967, un élevage florissant de Gl. tachinoides. Malgré une intoxication accidentelle par insecticide, qui a fait tomber les effectifs à moins de 400 femelles/jour, ceux-ci dépassaient 6 mois plus tard 2.300 femelles. La longévité maximale des femelles a été de 210 jours et la production de pupes a atteint 695 pupes pour 100 femelles. La technique utilisée est susceptible d'être appliquée à un élevage en masse en vue de la production de mâles stérile

    Undiagnosed Phenylketonuria Can Exist Everywhere:Results From an International Survey

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    Many countries do not have a newborn screening (NBS) program, and immigrants from such countries are at risk for late diagnosis of phenylketonuria (PKU). In this international survey, 52 of 259 patients (20%) with late diagnosed PKU were immigrants, and 145 of the 259 (55%) were born before NBS or in a location without NBS
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