Fuzzy directional enlacement landscapes

International audienceSpatial relations between objects represented in images are of high importance in various application domains related to pattern recognition and computer vision. By definition, most relations are vague, ambiguous and difficult to formalize precisely by humans. The issue of describing complex spatial configurations, where objects can be imbri-cated in each other, is addressed in this article. A novel spatial relation, called enlacement, is presented and designed using a directional fuzzy landscape approach. We propose a generic fuzzy model that allows to visualize and evaluate complex enlacement configurations between crisp objects, with directional granularity. The interest and the behavior of this approach is highlighted on several characteristic examples

Shear induced instabilities in layered liquids

Motivated by the experimentally observed shear-induced destabilization and reorientation of smectic A like systems, we consider an extended formulation of smectic A hydrodynamics. We include both, the smectic layering (via the layer displacement u and the layer normal p) and the director n of the underlying nematic order in our macroscopic hydrodynamic description and allow both directions to differ in non equilibrium situations. In an homeotropically aligned sample the nematic director does couple to an applied simple shear, whereas the smectic layering stays unchanged. This difference leads to a finite (but usually small) angle between n and p, which we find to be equivalent to an effective dilatation of the layers. This effective dilatation leads, above a certain threshold, to an undulation instability of the layers. We generalize our earlier approach [Rheol. Acta, vol.39(3), 15] and include the cross couplings with the velocity field and the order parameters for orientational and positional order and show how the order parameters interact with the undulation instability. We explore the influence of various material parameters on the instability. Comparing our results to recent experiments and molecular dynamic simulations, we find a good qualitative agreement.Comment: 15 pages, 12 figures, accepted for publication in PR

Blueprint for a minimal photoautotrophic cell: conserved and variable genes in Synechococcus elongatus PCC 7942

Background: Simpler biological systems should be easier to understand and to engineer towards pre-defined goals. One way to achieve biological simplicity is through genome minimization. Here we looked for genomic islands in the fresh water cyanobacteria Synechococcus elongatus PCC 7942 (genome size 2.7 Mb) that could be used as targets for deletion. We also looked for conserved genes that might be essential for cell survival.Results: By using a combination of methods we identified 170 xenologs, 136 ORFans and 1401 core genes in the genome of S. elongatus PCC 7942. These represent 6.5%, 5.2% and 53.6% of the annotated genes respectively. We considered that genes in genomic islands could be found if they showed a combination of: a) unusual G+C content; b) unusual phylogenetic similarity; and/or c) a small number of the highly iterated palindrome 1 (HIP1) motif plus an unusual codon usage. The origin of the largest genomic island by horizontal gene transfer (HGT) could be corroborated by lack of coverage among metagenomic sequences from a fresh water microbialite. Evidence is also presented that xenologous genes tend to cluster in operons. Interestingly, most genes coding for proteins with a diguanylate cyclase domain are predicted to be xenologs, suggesting a role for horizontal gene transfer in the evolution of Synechococcus sensory systems.Conclusions: Our estimates of genomic islands in PCC 7942 are larger than those predicted by other published methods like SIGI-HMM. Our results set a guide to non-essential genes in S. elongatus PCC 7942 indicating a path towards the engineering of a model photoautotrophic bacterial cell.Financial support was provided by grants BFU2009-12895-C02-01/BMC (Ministerio de Ciencia e Innovación, Spain), the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number 212894 and Prometeo/2009/092 (Conselleria d’Educació, Generalitat Valenciana, Spain) to A. Moya. Work in the FdlC laboratory was supported by grants BFU2008-00995/BMC (Spanish Ministry of Education), RD06/0008/1012 (RETICS research network, Instituto de Salud Carlos III, Spanish Ministry of Health) and LSHM-CT- 2005_019023 (European VI Framework Program). Dr. González-Domenech was supported by grant from the University of Granada. LD, thanks to financial support from Facultad de Ciencias, Universidad Nacional Autónoma de México

Gold-silver catalyzed straightforward one pot synthesis of pyrano[3,4- b]pyrrol-7(1H)-ones

CommunicationInternational audiencePyrano[3,4-b]pyrrol-7(1H)-one is a bicyclic structure that is rarely described in the literature but found in numerous polycyclic natural products as Lamellarins. This work presents an one-pot synthesis of pyrano[3,4-b]pyrrol-7(1H)-one substituted in 2-and 5-position. The reaction proceeds via a one-pot two steps 5-endo-dig and 6-endo-dig cyclizations catalyzed by a cationic gold complex with high regioselectivity

The evolution of the mass-size relation for early-type galaxies from z ∼1 to the present: dependence on environment, mass range and detailed morphology

International audienceWe study the dependence of the galaxy size evolution on morphology, stellar mass and large-scale environment for a sample of 298 group and 384 field quiescent early-type galaxies from the COSMOS survey, selected from z similar to 1 to the present, and with masses log(M/M-circle dot) \textgreater 10.5. From a detailed morphological analysis we infer that similar to 80 per cent of passive galaxies with mass log(M/M-circle dot) \textgreater 10.5 have an early-type morphology and that this fraction does not evolve over the last 6 Gyr. However, the relative abundance of lenticular and elliptical galaxies depends on stellar mass. Elliptical galaxies dominate only at the very high mass end -log(M/M-circle dot) \textgreater 11 - while S0 galaxies dominate at lower stellar masses -10.5 \textless log(M/M-circle dot) \textless 11. The galaxy size growth depends on galaxy mass range and early-type galaxy morphology, e.g. elliptical galaxies evolve differently than lenticular galaxies. At the low-mass end -10.5 \textless log(M/M-circle dot) \textless 11 - ellipticals do not show strong size growth from z similar to 1 to the present (10 to 30 per cent depending on the morphological classification). On the other end, massive ellipticals -log(M/M-circle dot) \textgreater 11.2 - approximately doubled their size. Interestingly, lenticular galaxies display different behaviour: they appear more compact on average and they do show a size growth of similar to 60 per cent since z = 1 independent of stellar mass range. We compare our results with state-of-the art semi-analytic models. While major and minor mergers can account for most of the galaxy size growth, we find that with present data and the theoretical uncertainties in the modelling we cannot state clear evidence favouring either merger or mass-loss via quasar and/or stellar winds as the primary mechanism driving the evolution. The galaxy mass-size relation and size growth do not depend on environment in the halo mass range explored in this work (field to group mass log(M-h/M-circle dot) \textless 14), i.e. group and field galaxies follow the same trends. At low redshift, where we examine both Sloan Digital Sky Survey and COSMOS groups, this result is at variance with predictions from some current hierarchical models that show a clear dependence of size growth on halo mass for massive ellipticals (log(M-*/M-circle dot) \textgreater 11.2). In future work, we will analyse in detail if this result is specific of the observations and model used in this work. Brightest Cluster Galaxies (BCG) and satellite galaxies lie on the same mass-size relation, at variance with predictions from hierarchical models, which predict that BCGs should have larger sizes than satellites because they experience more mergers in groups over the halo mass range probed

First demondtration of heat dissipation improvement in CMOS technology using Silicon-On-Diamond (SOD) substrates

International audienc

Physical Understanding of Program Injection and Consumption in Ultra-Scaled SiN Split-Gate Memories

International audienc

Etude pilote pour la mise en place d’un protocole de suivi du phyllodactyle d’Europe (Euleptes europaea) sur l’île de Port-Cros (Var, France)

International audienc