Gains in Power from Structured Two-Sample Tests of Means on Graphs

We consider multivariate two-sample tests of means, where the location shift between the two populations is expected to be related to a known graph structure. An important application of such tests is the detection of differentially expressed genes between two patient populations, as shifts in expression levels are expected to be coherent with the structure of graphs reflecting gene properties such as biological process, molecular function, regulation, or metabolism. For a fixed graph of interest, we demonstrate that accounting for graph structure can yield more powerful tests under the assumption of smooth distribution shift on the graph. We also investigate the identification of non-homogeneous subgraphs of a given large graph, which poses both computational and multiple testing problems. The relevance and benefits of the proposed approach are illustrated on synthetic data and on breast cancer gene expression data analyzed in context of KEGG pathways

Comparison between classical potentials and ab initio for silicon under large shear

The homogeneous shear of the {111} planes along the <110> direction of bulk silicon has been investigated using ab initio techniques, to better understand the strain properties of both shuffle and glide set planes. Similar calculations have been done with three empirical potentials, Stillinger-Weber, Tersoff and EDIP, in order to find the one giving the best results under large shear strains. The generalized stacking fault energies have also been calculated with these potentials to complement this study. It turns out that the Stillinger-Weber potential better reproduces the ab initio results, for the smoothness and the amplitude of the energy variation as well as the localization of shear in the shuffle set

Reduction of magnetostatic interactions in self-organized arrays of nickel nanowires using atomic layer deposition

Ordered arrays of magnetic nanowires are commonly synthesized by electrodeposition in nanoporous alumina templates. Due to their dense packing, strong magnetostatic interactions prevent the manipulation of wires individually. Using atomic layer deposition we reduce the diameter of the pores prior to electrodeposition. This reduces magnetostatic interactions, yielding fully remanent hysteresis loops. This is a first step towards the use of such arrays for magnetic racetrack memories

Assesing the frequency and clauses of out-of-stock events through store scanner data

This paper aims to provide an answer to the question of out-of-stock events (OOS), their frequency, the sales losses they generate, and their causes. The authors provide two contributions. They describe a new sales-based measure of OOS computed on the basis of store-level scanner data and identify several of the main determinants of OOS. They also introduce a significant distinction between complete and partial OOSout-of-stock events; store-level scanner data; assortment; retailing; marketing metrics

Dislocation formation from a surface step in semiconductors: an ab initio study

The role of a simple surface defect, such as a step, for relaxing the stress applied to a semiconductor, has been investigated by means of large scale first principles calculations. Our results indicate that the step is the privileged site for initiating plasticity, with the formation and glide of 60$^\circ$ dislocations for both tensile and compressive deformations. We have also examined the effect of surface and step termination on the plastic mechanisms

Employment suburbanisation, reverse commuting and travel behaviour by residents of the central city in the Paris metropolitan area

International audienceThis paper analyses the relationship between employment suburbanisation in the Paris metropolitan area, the growth of reverse commuting and changes in the weekday travel behaviour of working residents of the central city over a 20 years period. The results show that the number of reverse commuters has significantly increased because the municipality of Paris has lost many jobs but few working residents whilst employment has developed in the suburbs. Reverse commuters are mainly and increasingly high income professionals whose workplace is located close to the central city in employment sub-centres that are well served by public transport. Consequently reverse commuters have lower than average car use although differences exist and are related to their professional status. The policy implications of these findings are discussed in the conclusion

Connexins participate in the initiation and progression of atherosclerosis

Connexins are members of a large family of transmembrane proteins that form hemichannels or gap junctions. These channels allow the exchange of ions and small metabolites between the cytosol and extracellular space or between neighboring cells. Connexins are important in vascular physiology; they support radial and longitudinal cell-to-cell communication in the vascular wall. Four connexins are expressed in the vascular wall: Cx37, Cx40, Cx43, and Cx45. Their expression is not uniform in all blood vessels and varies with vascular territory and species. Significant changes in the expression pattern of vascular connexins have been described during the development of atherosclerosis, a progressive inflammatory disease. In this review, we provide an overview of (1) the tools used to study the involvement of connexins in atherosclerosis, (2) the participation of connexins in atherogenesis, (3) the increasing interest of a polymorphism in the human connexin37 gene as marker of cardiovascular disease, and (4) the possible therapeutic implications of connexin

Proposition d’une architecture composée de multiples processus de retour d’expérience coopérants

Cet article présente les premiers résultats d’une étude réalisée en partenariat avec l’entreprise Turbomeca traitant des problèmes engendrés par l’implémentation de processus de retour d’expérience dans une entreprise étendue. La première partie de l’article est dédiée à la définition et à la description des processus de retour d’expérience et des approches les plus avancées pour faciliter leur implémentation. Dans une seconde partie, nous montrons que dans une entreprise étendue, il est nécessaire de définir de multiples processus de retour d’expérience pour que l’approche soit adaptée aux différents niveaux de décisions et aux différents produits/technologies utilisés dans l’entreprise. Nous proposons une trame générale pour intégrer ces différents aspects et nous présentons une illustration d’un cas concret. Finalement, nous concluons sur l’originalité de notre proposition ses avantages et les perspectives de notre travail

La résilience des formes: La ceinture urbaine de la rive droite à Paris

International audienceThanks to a GIS for historical research of Paris, the researchers were able to show the inheritance of ancient forms in the current urban fabric, especially for the ancient meander of the Seine in right bank. Archaeological excavations in this ancient loop gave us information about the evolution of the flood plain of Paris during the Holocene. The resilience of this shape appears by crossing texts, mapping documents and archaeological data's. In the Middle Ages, the territories of "censive de Sainte-Opportune" were in the ancient meander and the ground was occupied by truck-farming. In the Middle Ages and the modern period, culverts and sewerage system are known to the place of ancient meander. In the 19th and until today, it has influenced the orientation of the plots of land and streets. Finally, during the big floods of 1910, the Seine returned in its ancient bed. This example shows that the forms are passed on in the time. The geographical convergences stays because structures and functions are changing.La mise en place d'un SIG historique pour la ville de Paris permet d'appréhender l'héritage urbain des écoulements, et notamment du grand paléoméandre de la rive droite. Des fouilles archéologiques sont venues éclairer l'évolution géomorphologique de la plaine alluviale de Paris durant l'Holocène. Toutefois la prégnance de cette zone humide dans la structuration de l'espace urbain parisien n'a pas encore été suffisamment soulignée. Le croisement entre des données textuelles, planimétriques et archéologiques montre assez nettement la résilience de cette forme : elle marque, sur la longue durée, les espaces seigneuriaux (censive de Sainte-Opportune), l'exploitation pastorale puis agricole du sol à partir du milieu du XIIe siècle, les infrastructures techniques (réseau d'égouts du Moyen Âge et de l'époque moderne), le tissu urbain (réseau viaire et trames des XIXe et XXe siècles). Pourtant produites dans des contextes documentaires très variés, la spatialisation de ces données atteste la convergence géographique du phénomène et constitue une nouvelle pièce à verser au dossier de la transmission des formes au-delà de la seule temporalité de l'aménagement humain

Cartographie des crues centennales à Paris (1740, 1910)

National audienceMap-making the centennial floods of the Seine in Paris allows to understand in a new scientific way the relationship between societies and spaces in urban context. Contemporary maps of the flooding of 1740 and 1910 were spatialized in the GIS Alpage and show the impact of floods in the parisian topography. By a dual approach of flooded areas, both chronological and typological, we can measure the consequences of slow process of detachment of the city and the river. This work unveils the specificities of each bank and raises questions about the causes of this different evolution. The containment of the Seine, very tough since the XIXthc., far from causing the end of risk for riverside societies, changed the geography of urban spaces with high risk river, and played a role in the revival of the old channel of the river on the right bank.Cartographier les crues centennales de la Seine à Paris permet d'appréhender sous un autre regard scientifique la relation entre les sociétés et le milieu fluvial en contexte urbain. Des sources planimétriques contemporaines des crues de 1740 et 1910 ont été spatialisées dans le SIG-Alpage et montrent l'impact des inondations dans la topographie parisienne. Par une double approche des zones inondées, à la fois chronologique et typologique, il est possible de mesurer les conséquences du lent processus de détachement de la ville et du fleuve. Ce travail dévoile des spécificités propres à chaque rive et soulève des questionnements sur les causes de cette évolution différente. L'endiguement de la Seine, très rigide à partir du XIXe siècle, loin d'entraîner la disparition du risque fluvial pour les sociétés riveraines, a modifié la géographie des espaces urbains à fort risque fluvial, et participé à faire rejouer la forme de l'ancien cours du fleuve sur la rive droite