846 research outputs found

    Epidemic typhus imported from Algeria.

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    We report epidemic typhus in a French patient returning from Algeria. The diagnosis was confirmed by serologic testing and the isolation of Rickettsia prowazekii in blood. Initially the patient was thought to have typhoid fever. Because body lice are prevalent in industrialized regions, the introduction of typhus to pediculosis-endemic areas poses a serious public health risk

    Self-cleaning on a higher order mode in ytterbium-doped multimode fiber with parabolic profile

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    We experimentally demonstrate polarization-dependent Kerr spatial beam self-cleaning into the LP11 mode of an Ytterbium-doped multimode optical fiber with parabolic gain and refractive index profiles

    The Duration-Based Measurement of Unemployment: Estimation Issues and an Application to Male-Female Unemployment Differences in France

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    This paper examines how unemployment can be measured in normative fashion - taking into account the mean and inequality of spell lengths - and how the extent of unemployment can be estimated from cross section data of the type found in labour force surveys. The issue is not straightforward since in these surveys completed durations of unemployed individuals are not observed yet they constitute the basis for calculating the kind of index that has been proposed to measure the extent of unemployment in a way that goes beyond the unemployment rate. The index proposed by Shorrocks has robust normative foundations and has an equivalent representation in terms of average complete duration and the density of completed durations. Building upon earlier work applied in the United States for estimating the first of these, we present a method that enables the index to be calculated based on an estimate of the density of completed durations. The approach is illustrated in the context of comparing male-female unemployment differences in France, where historically female unemployment has been higher than that of males

    Pluie de solitons dans un laser à fibre co-dopée Er:Yb en forme de huit

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    Nous rapportons ici l\u27observation expérimentale d\u27un comportement collectif d\u27un ensemble de soliton, appelé pluie de solitons, dans un laser à fibre en forme de huit avec un miroir à boucle non linéaire (NOLM). Cette dynamique non linéaire a été précédemment observée dans un laser à fibre verrouillé passivement par la technique de rotation de polarisation non linéaire. A partir d\u27un fond continu, des solitons se créent et dérivent vers la phase condensée de plusieurs solitons. L\u27observation de cette dynamique tend à renforcer l\u27idée de l\u27universalité du comportement collectif des solitons. 

    Harmonic dissipative soliton resonance square pulses in an anomalous dispersion passively mode-locked fiber ring laser

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    We demonstrate the generation of dissipative soliton resonance square pulses from a co-doped Er:Yb double-clad fiber ring laser operating in an all anomalous dispersion regime. The obtained pulses have a repetition rate of 672 kHz and a pulse energy of 409 nJ. By carefully adjusting the polarization controllers while increasing the pump power, the square pulse can split into a series of identical equally spaced smaller square pulses up to the 13th harmonic of the fundamental repetition frequency. The average output energy of the square pulses follows a scaling law versus the harmonic orde

    Soliton pattern formation in figure-of-eight laser

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    We investigate the soliton pattern formation in an erbium-doped figure-of-eight double-clad fiber laser. The mode-locking is realized with a nonlinear amplifying loop mirror. Different soliton complexes have been obtained similar to those obtained when the mode-locking is achieved through the nonlinear polarization rotation technique

    La pêche artisanale au Sénégal : qualité de la matière première destinée aux entreprises exportatrices

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    Les conditions d’hygiène de la pêche artisanale au Sénégal ne respectent pas toujours les normes de qualité requises. Ce présent travail se propose d’étudier la qualité de trois espèces de poissons démersaux ; la sole limande (Syacium guineensis), le mérou à points bleus (Cephalopholis taeniops) et le rouget (Pseudupeneus prayensis) débarqués par la pêche artisanale. Ces espèces sont suivies depuis la capture jusqu’à leur acheminement en usine. L’évaluation sensorielle de la fraîcheur du poisson a consisté à tester la qualité par le toucher, l’odorat, la vue et le goût. Le dosage de l’azote basique volatil total (ABVT) a permis de déterminer la teneur totale en azote des bases azotées volatiles résultant de la dégradation des composés azotés du poisson lors de l’altération. La méthode d’analyse microbiologique utilisée est celle qui consiste à incorporer un volume donné de la prise d’essai et de ses dilutions dans un milieu de culture solide. A l’analyse sensorielle, les trois espèces, aux différentes étapes, étaient de très bonne qualité. Les valeurs de la flore mésophile aérobie sur le poisson à la capture sont très faibles contrairement au débarquement et à l’entrée en usine. Au niveau des branchies et de la peau, les résultats montrent une augmentation significative de la flore au débarquement et à l’entrée en usine. Au niveau des viscères, la flore augmente jusqu’au débarquement puis décroît. Les résultats des analyses chimiques ne reflètent pas forcément les risques de dégradation du poisson.Mots-clés : pêche artisanale, poisson, qualité matière première, exportation, Sénégal.Artisanal fisheries in Senegal: Quality of raw materials for exporting companiesHygienic conditions of artisanal fisheries in Senegal do not always respect the required quality standards. This study expects to scrutinize the quality of bottom fish sole (Syacium guineensis), grouper blue spotted (Cephalopholis taeniops), red mullet (Pseudupeneus prayensis) disembarked by artisanal fisheries. These species are followed since the capture until their routing in factory. The sensory evaluation of fish freshness was to test the quality through touch, smell, sight and taste. The determination of total volatile basic nitrogen (ABVT) allowed determining the total nitrogen content of volatile nitrogenous bases resulting from the degradation of nitrogenous compounds in fish spoilage. The used-microbiological-method is the one that consist in incorporating a given volume of the sample and its dilutions in a solid cultural medium. The results of sensory analysis on the three species at different stopovers were very good. The values of the aerobic mesophilic flora on the fish caught are very low compared to the one landed at the entrance to the factory. At the gills and skin, the findings show a significant increase in flora and landed at the entrance to the factory. In the viscera, flora increases and then decreases until the debarkation. The results of sensory and chemical analysis may not reflect the risks of degradation of fish.Keywords : artisanal fisheries, fish, quality, raw materials, exportation, Senegal
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