Effect of the Structure of Amido-polynitrogen Molecules on the Complexation of Actinides

AbstractThe complexation and solvent extraction of Eu(III) and actinides in different oxidation states (Am(III), Pu(IV), Np(V)) by bitopic molecules with a dipyridyl-phenanthroline cycle as nitrogen unit and one or two amido functions are described. The complexation has been studied in methanol-water solution with hydrophilic molecules to enhance knowledge about this new family of ligands and to identify the most interesting structural effect. Some extraction tests have been performed with lipophilic molecules of the family to check the possible utility of the new class of ligands under representative fuel reprocessing conditions. These first studies have demonstrated that the presence of a preorganized N-donors unit like dipyridyl-phenanthroline improves the ligand's affinity for actinides and its An/Ln selectivity

Effet d'une expérimentation de brassage artificiel epilimnique par aération sur les poussées cyanobactériennes dans la retenue hypereutrophe de Grangent (France)

Dans la retenue hypereutrophe de Grangent, le phytoplancton estival est dominé par la cyanobactérie Microcystis aeruginosa. Dans le but de lutter contre la formation de ces blooms cyanobactériens, une expérimentation de brassage artificiel épilimnique par aération a été réalisée en 1997-1998. Ce dispositif avait pour but de créer des turbulences supprimant l'avantage adaptatif que constitue, chez M. aeruginosa, la faculté de réguler sa flottabilité. Il devait également permettre l'homogénéisation des teneurs en oxygène dissous, la réduction des pics de pH, de la turbidité des eaux superficielles et des teneurs en ammonium.Les résultats escomptés ont été vérifiés pour les paramètres physicochimiques. Les valeurs se sont révélées plus homogènes, mais seulement à proximité des lignes de brassage et uniquement jusqu'à 10 m de profondeur. En revanche, les blooms cyanobactériens n'ont pas été réduits. Il apparaît même au contraire que, sous l'influence du mélange, les cyanobactéries ont eu à leur disposition une plus grande quantité de nutriments qu'elles ont utilisés pour constituer des réserves glucidiques. Ainsi, en aval de la zone brassée, ces réserves ont permis une synthèse protéique plus importante.Sur la retenue de Grangent, le dispositif de brassage peut offrir une solution palliative du point de vue touristique en limitant l'accumulation de cyanobactéries en surface, mais il ne permet pas d'éliminer, ni même de diminuer, les proliférations de M. aeruginosa en période estivale.In the reservoir of Grangent, a highly eutrophic lake located on the upper part of the Loire River, about 10 miles south of Saint-Étienne (France), Microcystis aeruginosa usually dominates the phytoplankton community in late summer and early autumn for many years. Mass developments of this cyanobacterium led to serious difficulties in multi-purpose usage. In order to fight against blooms, an epilimnic artificial mixing was experimented. M. aeruginosa is adapted to stable stratification of the water column. Therefore, partial destratification or bubbling with air are employed to replace M. aeruginosa by better grazable, non- " blooming " and non-toxic species. This cyanobacterium is supposed to lose its advantage of buoyancy and to reduce his growth. This system was also employed to reduce peaks of pH, turbidity of surface waters and concentration of NH4 and to homogenize the dissolved oxygen concentration inside the water column. Three lines of mixing were tested in 1998: one located at "Châtelet", upstream of reservoir, measuring 700 m at 11 m depth; one near the beach of Saint-Victor, with the same length and immersed to 15 m depth and, finally, a line of 400 m, near the port, at 16 m depth (figure 1).Data were collected from representative sites, upstream, near and downstream the artificial mixing. They were sampled weekly since April to November 1998. At each site the vertical profiles of temperature and dissolved oxygen were measured (figure 2). For each sample, the parameters following were analyzed: pH, NO3, NH4, PO4, carbohydrates, proteins, chlorophyll a and phytoplankton enumeration.Concerning the physicochemical parameters, the assumptions were checked: the values appeared more homogeneous near the lines of mixing than at the other stations. For example, the average temperatures varied between 20,6°C (at 10 m depth) and 21,3°C (at 0,5 m depth) at Saint-Victor. This variation reached 1,3°C at the station Camaldules. On the other hand, this effect was perceived only up to 10 m of depth and at a limited distance of mixing.In the same way, the colonies of M. aeruginosa were mixed in the water column but only up 10 m depth and near mixing. Moreover, their growth has not decreased on the whole of reservoir. In period of bloom (August 25), G/P ratio was higher in the mixing zone than in the neighbourhoods, primarily because of an increase in carbohydrates (figure 3). In the mixed zone, M. aeruginosa seemed to benefit greater quantity of mineral elements it could use to constitute carbohydrates reserves (figure 4). In this way, when the conditions that became less favourable, like downstream, cyanobacteria were able to follow their development by synthesizing proteins starting from their reserves in carbohydrates.In the reservoir of Grangent, artificial mixing did not allow to fight effectively against blooms of cyanobacteria. Colonies of M. aeruginosa were simply diluted in the water column near mixing but did not reduce their growth

10 Years of Object-Oriented Analysis on H1

Over a decade ago, the H1 Collaboration decided to embrace the object-oriented paradigm and completely redesign its data analysis model and data storage format. The event data model, based on the RooT framework, consists of three layers - tracks and calorimeter clusters, identified particles and finally event summary data - with a singleton class providing unified access. This original solution was then augmented with a fourth layer containing user-defined objects. This contribution will summarise the history of the solutions used, from modifications to the original design, to the evolution of the high-level end-user analysis object framework which is used by H1 today. Several important issues are addressed - the portability of expert knowledge to increase the efficiency of data analysis, the flexibility of the framework to incorporate new analyses, the performance and ease of use, and lessons learned for future projects.Comment: 14th International Workshop on Advanced Computing and Analysis Techniques in Physics Researc

Numerical simulation of strongly nonlinear and dispersive waves using a Green-Naghdi model

We investigate here the ability of a Green-Naghdi model to reproduce strongly nonlinear and dispersive wave propagation. We test in particular the behavior of the new hybrid finite-volume and finite-difference splitting approach recently developed by the authors and collaborators on the challenging benchmark of waves propagating over a submerged bar. Such a configuration requires a model with very good dispersive properties, because of the high-order harmonics generated by topography-induced nonlinear interactions. We thus depart from the aforementioned work and choose to use a new Green-Naghdi system with improved frequency dispersion characteristics. The absence of dry areas also allows us to improve the treatment of the hyperbolic part of the equations. This leads to very satisfying results for the demanding benchmarks under consideration

A splitting approach for the fully nonlinear and weakly dispersive Green-Naghdi model

The fully nonlinear and weakly dispersive Green-Naghdi model for shallow water waves of large amplitude is studied. The original model is first recast under a new formulation more suitable for numerical resolution. An hybrid finite volume and finite difference splitting approach is then proposed. The hyperbolic part of the equations is handled with a high-order finite volume scheme allowing for breaking waves and dry areas. The dispersive part is treated with a classical finite difference approach. Extensive numerical validations are then performed in one horizontal dimension, relying both on analytical solutions and experimental data. The results show that our approach gives a good account of all the processes of wave transformation in coastal areas: shoaling, wave breaking and run-up

Analyse préliminaire de la valeur verte pour les logements

Analyse préliminaire de la valeur verte pour les logement

Comparison of machine learning algorithms in restaurant revenue prediction

In this paper, we address several aspects of applying classical machine learning algorithms to a regression problem. We compare the predictive power to validate our approach on a data about revenue of a large Russian restaurant chain. We pay special attention to solve two problems: data heterogeneity and a high number of correlated features. We describe methods for considering heterogeneity—observations weighting and estimating models on subsamples. We define a weighting function via Mahalanobis distance in the space of features and show its predictive properties on following methods: ordinary least squares regression, elastic net, support vector regression, and random forest.</p

Genetic parameters for�resistance to the Salmonella abortusovis vaccinal strain Rv6 in sheep

An experimental population (1216 lambs from 30 sires) of the Inra401 sheep was created in an Inra flock to allow QTL detection for susceptibility to Salmonella infection, wool and carcass traits. The Inra401 is a sheep composite line developed from two breeds: Berrichon du Cher and Romanov. At 113 days of age on average, the lambs were inoculated intravenously with 10(8 )Salmonella abortusovis Rv6 (vaccinal strain). They were slaughtered 10 days after the inoculation. Several traits were measured at inoculation and/or slaughtering to estimate the genetic resistance of the lambs to Salmonella infection: specific IgM and IgG1 antibody titres, body weight loss, spleen and pre-scapular node weights and counts of viable Salmonella persisting in these organs. This paper presents a quantitative analysis of the genetic variability of the traits related to salmonellosis susceptibility. The heritabilities of the traits varied between 0.10 and 0.64 (significantly different from zero). Thus, in sheep as well as in other species, the determinism of resistance to Salmonella infection is under genetic control. Moreover, the correlations between the traits are in agreement with the known immune mechanisms. The genetic variability observed should help QTL detection