372 research outputs found

    Clerval – Rue basse : atelier de potier (xviie s.)

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    Des travaux de rénovation et de construction dans le quartier de la rue basse à Clerval ont amené la découverte fortuite d’un dépotoir de potier-faïencier du xviie s., ainsi que des vestiges probables de son atelier. Ces vestiges étudiés par l’association du Vieux Clerval concernent deux fosses maçonnées contiguës de plan rectangulaire. La première fosse mesure 1 m x 1,75 m sur une profondeur de 0,75 m. La seconde fosse, profonde de 0,50 m, large de 1 m environ, n’a pu être dégagée que sur 1,..

    Luminescent Ions in Silica-Based Optical Fibers

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    We present some of our research activities dedicated to doped silica-based optical fibers, aiming at understanding the spectral properties of luminescent ions, such as rare-earth and transition metal elements. The influence of the local environment on dopants is extensively studied: energy transfer mechanisms between rare-earth ions, control of the valence state of chromium ions, effect of the local phonon energy on thulium ions emission efficiency, and broadening of erbium ions emission induced by oxide nanoparticles. Knowledge of these effects is essential for photonics applications

    Estudio: la mediación penal : Comentario del articulo 6 de la ley N° 93-2 del 4 de enero de 1993 sobre la reforma del procedimiento penal

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    A pesar de los deseos expresados en numerosos textos, hasta la sanción de la ley N° 93-2 del 4 de enero de 1993 no existió un verdadero marco jurídico para el ejercicio de la mediación penal. Sin embargo, algunas prácticas se llevaron a cabo por iniciativa de la policía, del Ministerio Público, del juez de instrucción, incluso hasta de una jurisdicción de sentencia. Cumplen esta tarea, en el campo social, los inspectores de trabajo y en las sociedades comerciales, los auditores. El mérito de la reciente ley es haber previsto en el artículo 6 la posibilidad de una mediación penal, agregando un párrafo al artículo 41 del Código de Procedimiento Penal. La mediación penal consagrada de esta forma se puso en práctica antes de que entre en vigencia la ley, en más de 70 tribunales en estrecha relación con los Colegios de Abogados, las comunidades locales y las asociaciones de ayuda a la víctima. A pesar de que el artículo 6 de la ley del 4 de enero de 1993 responde a varias de las preguntas que se hacían los procuradores, son muchas las que quedaron sin respuesta. El artículo 41, último párrafo, del Código de Procedimiento Penal, resultante de la ley del 4 de enero de 1993, permite al Procurador de la República recurrir a la mediación cuando se encuentran reunidas las circunstancias enumeradas en la ley (I). Pero una vez decidida la mediación debe poder cumplirse ya que el nuevo texto presenta más interrogantes que respuestasFacultad de Ciencias Jurídicas y Sociale

    Real-time 2D separation by LC Ă— differential ion mobility hyphenated to mass spectrometry

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    The liquid chromatography-mass spectrometry (LC-MS) analysis of complex samples such as biological fluid extracts is widespread when searching for new biomarkers as in metabolomics. The success of this hyphenation resides in the orthogonality of both separation techniques. However, there are frequent cases where compounds are co-eluting and the resolving power of mass spectrometry (MS) is not sufficient (e.g., isobaric compounds and interfering isotopic clusters). Different strategies are discussed to solve these cases and a mixture of eight compounds (i.e., bromazepam, chlorprothixene, clonapzepam, fendiline, flusilazol, oxfendazole, oxycodone, and pamaquine) with identical nominal mass (i.e., m/z 316) is taken to illustrate them. Among the different approaches, high-resolution mass spectrometry or liquid chromatography (i.e., UHPLC) can easily separate these compounds. Another technique, mostly used with low resolving power MS analyzers, is differential ion mobility spectrometry (DMS), where analytes are gas-phase separated according to their size-to-charge ratio. Detailed investigations of the addition of different polar modifiers (i.e., methanol, ethanol, and isopropanol) into the transport gas (nitrogen) to enhance the peak capacity of the technique were carried out. Finally, a complex urine sample fortified with 36 compounds of various chemical properties was analyzed by real-time 2D separation LCĂ—DMS-MS(/MS). The addition of this orthogonal gas-phase separation technique in the LC-MS(/MS) hyphenation greatly improved data quality by resolving composite MS/MS spectra, which is mandatory in metabolomics when performing database generation and searc

    Improvement of the Tm3+:3H4 level lifetime in silica optical fibres by lowering the local phonon energy

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    The role of some glass network modifiers on the quantum efficiency of the near-infrared fluorescence from the 3H4 level of Tm3+ ion in silica-based doped fibres is studied. Modifications of the core composition affect the spectroscopic properties of Tm3+ ion. Adding 17.4 mol% of AlO3/2 to the core glass caused an increase of the 3H4 level lifetime up to 50 ÎĽ\mus, 3.6 times higher than in pure silica glass. The quantum efficiency was increased from 2% to approximately 8%. On the opposite, 8 mol% of PO5/2 in the core glass made the lifetime decrease downto 9 ÎĽ\mus. These changes of Tm3+ optical properties are assigned to the change of the local phonon energy to which they are submitted by modifiers located in the vicinity of the doping sites. Some qualitative predictions of the maximum achievable quantum efficiency are possible using a simple microscopic model to calculate the non-radiative de-excitation rates

    Post-depositional redistribution of trace metals in reservoir sediments of a mining/smelting-impacted watershed (the Lot River, SW France)

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    International audienceMining/smelting wastes and reservoir sediment cores from the Lot River watershed were studied using mineralogical (XRD, SEM-EDS, EMPA) and geochemical (redox dynamics, selective extractions) approaches to characterize the main carrier phases of trace metals. These two approaches permitted determining the role of post-depositional redistribution processes in sediments and their effects on the fate and mobility of trace metals. The mining/smelting wastes showed heterogeneous mineral compositions with highly variable contents of trace metals. The main trace metal-bearing phases include spinels affected by secondary processes, silicates and sulfates. The results indicate a clear change in the chemical partitioning of trace metals between the reservoir sediments upstream and downstream of the mining/smelting activities, with the downstream sediments showing a 2-fold to 5-fold greater contribution of the oxidizable fraction. This increase was ascribed to stronger post-depositional redistribution of trace metals related to intense early diagenetic processes, including dissolution of trace metal-bearing phases and precipitation of authigenic sulfide phases through organic matter (OM) mineralization. This redistribution is due to high inputs (derived from mining/smelting waste weathering) at the water-sediment interface of (i) dissolved SO4 promoting more efficient OM mineralization, and (ii) highly reactive trace metal-bearing particles. As a result, the main trace metal-bearing phases in the downstream sediments are represented by Zn- and Fe-sulfides, with minor occurrence of detrital zincian spinels, sulfates and Fe oxyhydroxides. Sequestration of trace metals in sulfides at depth in reservoir sediments does not represent long term sequestration owing to possible resuspension of anoxic sediments by natural (floods) and/or anthropogenic (dredging, dam flush) events that might promote trace metal mobilization through sulfide oxidation. It is estimated that, during a major flood event, about 870 t of Zn, 18 t of Cd, 25 t of Pb and 17 t of Cu could be mobilized from the downstream reservoir sediments along the Lot River by resuspension-induced oxidation of sulfide phases. These amounts are equivalent to 13-fold (Cd), not, vert, similar6-fold (Zn), 4-fold (Pb) the mean annual inputs of the respective dissolved trace metals into the Gironde estuary

    Roles of regional hydrodynamic and trophic contamination in cadmium bioaccumulation by Pacific oysters in the Marennes-Oléron Bay (France)

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    International audienceThe Marennes-Oléron Bay, hosting the largest oyster production in France, is influenced by the historic polymetallic pollution of the Gironde Estuary. Despite management efforts and decreasing emissions in the Gironde watershed, cadmium levels in oysters from the bay are close to the consumption limit (5 lg g À1 dw, EC). From mid April to mid July 2009, we investigated the role of tidal resuspension and regional hydrodynamics on Cd speciation (seawater, SPM, phytoplankton, sediment, microphytobenthos) and bioaccumulation in 18 month-old oysters (gills, digestive glands, rests of tissues) reared under natural conditions (i) at $60 cm above the sediment and (ii) on the sediment surface. Dissolved and particulate Cd concentrations in surface and bottom waters were similar and constant over tidal cycle suggesting the absence of Cd release during sediment resuspension. Temporal dissolved and particulate Cd concentrations were closely related to Gironde Estuary water discharges, showing increasing concentrations during flood situations and decreasing concentrations afterwards. Cd depletion in the water column was associated with increasing Cd in the [20-100 lm] plankton fraction, suggesting Cd bioaccumulation. After 3 months, enrichment factors of Cd in tissues of oysters exposed in the water column and directly on the sediment were respectively 3.0 and 2.2 in gills, 4.7 and 3.2 in digestive glands and 4.9 and 3.4 in remaining tissues. Increasing Cd bioaccumulation in gills, digestive glands and remaining tissues can be related to elevated dissolved Cd in the bay, suggesting gill contamination via the direct pathway and subsequent internal redistribution of Cd to other organs and tissues. Elevated Cd contents in oysters reared on tables could be attributed to different trophic Cd transfer (phytoplankton versus micro-phytobenthos) or to different oyster metabolisms between the rearing conditions as suggested by metal-lothionein concentrations

    Thulium environment in a silica doped optical fibre

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    Thulium-doped optical fibre amplifiers (TDFA) are developed to extend the optical telecommunication wavelength division multiplexing (WDM) bandwidth in the so-called S-band (1460-1530 nm). The radiative transition at 1.47 lm (3H4 -> 3F4) competes with a non-radiative multi-phonon de-excitation (3H4 -> 3H5). The quantum efficiency of the transition of interest is then highly affected by the phonon energy (Ep) of the material. For reliability reasons, oxide glasses are preferred but suffer from high phonon energy. In the case of silica glass, Ep is around 1100 cm-1 and quantum efficiency is as low as 2%. To improve it, phonon energy in the thulium environment must be lowered. For that reason, aluminium is added and we explore three different core compositions: pure silica, and silica slightly modified with germanium or phosphorus. The role of aluminium is studied through fluorescence decay curves, fitted according to the continuous function decay analysis. From this analysis, modification of the thulium local environment due to aluminium is evidenced
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