Study of Flow and Energy Dissipation in Stepped Spillways

We present in this work the quantitative and qualitative study of the flow in the stepped spillways. The experimental measurement is realized on the reduced model. Different flow configurations on a spillway are described. New experimental results linked to the flow aspect and to the energy dissipation after the passage over the spillway are presented. The experimental results relative to the energy dissipation are analysed. They are compared thereafter to the results of the experiences and models found in other research works

Numerical analysis of bonded composite patch efficiency in the case of lateral U and V-notched aluminium panels

In this study, the finite element method is applied to investigate the mechanical behavior of aluminium notched structures reinforced by composite patch. In order to evaluate the efficiency of patches in the case of lateral semicircular and V-notches, it is very important to analyze the stress distribution at the notch tip and to take in consideration the influence of the geometrical and mechanical properties of the patch and the adhesive. Simple and double patch were used as reinforcement techniques. Results showed that the stress concentration factor is reduced at the notch tip by using a double patch reinforcement. This reduction becomes more noticeable when the patch thickness increases

Properties of Healthcare Teaming Networks as a Function of Network Construction Algorithms

Network models of healthcare systems can be used to examine how providers collaborate, communicate, refer patients to each other. Most healthcare service network models have been constructed from patient claims data, using billing claims to link patients with providers. The data sets can be quite large, making standard methods for network construction computationally challenging and thus requiring the use of alternate construction algorithms. While these alternate methods have seen increasing use in generating healthcare networks, there is little to no literature comparing the differences in the structural properties of the generated networks. To address this issue, we compared the properties of healthcare networks constructed using different algorithms and the 2013 Medicare Part B outpatient claims data. Three different algorithms were compared: binning, sliding frame, and trace-route. Unipartite networks linking either providers or healthcare organizations by shared patients were built using each method. We found that each algorithm produced networks with substantially different topological properties. Provider networks adhered to a power law, and organization networks to a power law with exponential cutoff. Censoring networks to exclude edges with less than 11 shared patients, a common de-identification practice for healthcare network data, markedly reduced edge numbers and greatly altered measures of vertex prominence such as the betweenness centrality. We identified patterns in the distance patients travel between network providers, and most strikingly between providers in the Northeast United States and Florida. We conclude that the choice of network construction algorithm is critical for healthcare network analysis, and discuss the implications for selecting the algorithm best suited to the type of analysis to be performed.Comment: With links to comprehensive, high resolution figures and networks via figshare.co

Improving Scalability and Maintenance of Software for High-Performance Scientific Computing by Combining MDE and Frameworks

International audienceIn recent years, numerical simulation has attracted increasing interest within industry and among academics. Paradoxically, the development and maintenance of high performance scientific computing software has become more complex due to the diversification of hardware architectures and their related programming languages and libraries. In this paper, we share our experience in using model-driven development for numerical simulation software. Our approach called MDE4HPC proposes to tackle development complexity by using a domain specific modeling language to describe abstract views of the software. We present and analyse the results obtained with its implementation when deriving this abstract model to target Arcane, a development framework for 2D and 3D numerical simulation software

Étude expérimentale de la bio-accumulation des lanthanides chez la moule Mytilus galloprovincialis (Lamarck) du littoral méditerranéen marocain

La microscopie ionique et la microanalyse X ont été utilisées pour détecter in situ, sur coupes histologiques, les éléments bio-accumulés dans la moule Mytilus galloprovincialis, contaminée expérimentalement in vitro par le cérium, le thulium et le lanthane. Les éléments absorbés, sous forme soluble à l’état de traces dans les organites cibles (les lysosomes), sont concentrés sous forme de précipités de phosphate insolubles dans les cellules épithéliales des branchies, des glandes digestives et des palpes labiaux

Why do herbivorous mites suppress plant defenses?

Plants have evolved numerous defensive traits that enable them to resist herbivores. In turn, this resistance has selected for herbivores that can cope with defenses by either avoiding, resisting or suppressing them. Several species of herbivorous mites, such as the spider mites Tetranychus urticae and Tetranychus evansi, were found to maximize their performance by suppressing inducible plant defenses. At first glimpse it seems obvious why such a trait will be favored by natural selection. However, defense suppression appeared to readily backfire since mites that do so also make their host plant more suitable for competitors and their offspring more attractive for natural enemies. This, together with the fact that spider mites are infamous for their ability to resist (plant) toxins directly, justifies the question as to why traits that allow mites to suppress defenses nonetheless seem to be relatively common? We argue that this trait may facilitate generalist herbivores, like T. urticae, to colonize new host species. While specific detoxification mechanisms may, on average, be suitable only on a narrow range of similar hosts, defense suppression may be more broadly effective, provided it operates by targeting conserved plant signaling components. If so, resistance and suppression may be under frequency-dependent selection and be maintained as a polymorphism in generalist mite populations. In that case, the defense suppression trait may be under rapid positive selection in subpopulations that have recently colonized a new host but may erode in relatively isolated populations in which host-specific detoxification mechanisms emerge. Although there is empirical evidence to support these scenarios, it contradicts the observation that several of the mite species found to suppress plant defenses actually are relatively specialized. We argue that in these cases buffering traits may enable such mites to mitigate the negative side effects of suppression in natural communities and thus shield this trait from natural selection

Bio-accumulation des métaux lourds chez l'oursin Paracentrotus lividus (Lamarck) sur la côte Est de la Méditerranée marocaine

La composition minérale de l’oursin (Paracentrotus lividus), échinoderme benthique fréquent dans la côte Est de la Méditerranée marocaine, concorde avec celle de l’eau du site de prélèvement. En outre, la comparaison des valeurs obtenues sur des oursins récoltés en automne avec celles élevées qui sont obtenues sur des oursins récoltés au printemps suppose l’existence d’un cycle métabolique saisonnier. Les teneurs observées dans l’épithélium digestif et dans les gonades laissent présager les possibilités d’échanges métaboliques entre les systèmes digestif et reproducteur. Ce phénomène est non étudié jusqu’à présent chez les Échinides. Les lysosomes sont les organites cibles où la plupart des éléments, absorbés à l’état de traces sous forme soluble, se concentrent sous forme de précipités de phosphates insolubles