La gestion globale des garanties.

Le projet 3G (gestion globale des garanties), lancé en juillet 2006 par la Banque de France et la place de Paris, avait l’ambition de refondre les modalités de mise en garantie des actifs dans le cadre des opérations de refinancement de l’Eurosystème. Mis en service le 18 février 2008, 3G répond aujourd’hui complètement aux attentes des établissements de crédit en leur permettant d’optimiser la gestion de leur collatéral.

Fixatives, Decalcifiers and Ultrastructure of the organic remnants from mural Nacreous Layers of Fossil Cephalopod Shells

The ultrastructure of the organic remnants has been compared in the TEM, after decalcification of the mural nacre of ammonites and fossil nautiloids by EDTA, which removes a soluble fraction, and after fixation and decalcification by formaldehyde-cetyl-pyridinium chloride-EDTA (CPC method) and chromium sulphate solutions, which are both considered to insure a better preservation of these organic remains. The loose networks of altered trabeculae, frequently fused into membranes, which constitute the ultrastructure of the fossil organic remnants of nacre after decalcification by EDTA, are also found in the samples treated by the CPC method and by chromium sulphate. Continuous membranes, superimposed on the networks, are especially abundant in the material treated by chromium sulphate. It is concluded that the networks of altered trabeculae are not artifacts, but are the representative ultrastructures of the organic remnants of the nacreous layers in the fossils studied so far. It is suggested that disappearance of EDTA soluble substances does not distinctly alter the ultrastructure of the fossil organic residues

Phylogenetic relationships among basal-most arthrodontous mosses with special emphasis on the evolutionary significance of the Funariineae

The classification of the Bryopsida (mosses) has been based primarily on the variation of sporophytic characters i.e., architectural features of the peristome teeth that line the capsule mouth. Five arthrodontous peristome types have been recognized. Whether peristome types define natural groups and how they are evolutionary related has, however, remained unclear. Nucleotide sequence data from one nuclear and two chloroplast loci are generated and compiled to test two contrasting hypotheses regarding the ancestral peristome type in the Arthrodonteae. The genomic data partitions are incongruent with regard to the phylogenetic signal they carry. All phylogenetic analyses converge toward the polyphyly of the Funariineae and the Funariaceae. The Funariaceae are defined by the loss of a codon in the rps4 gene. Goniomitrium acuminatum, the type of the genus, lacks this deletion, and is always resolved within the Haplolepideae

Management of placenta accreta.

International audienceCesarean hysterectomy is considered the reference standard treatment for placenta accreta. In young women who want the option of future pregnancy and agree to close follow-up monitoring, conservative treatment is a valid option. Several key points of both cesarean hysterectomy and conservative treatment remain debatable, such as timing of delivery, attempted removal of the placenta, use of temporal internal iliac occlusion balloon catheters, ureteral stents, prophylactic embolization, and methotrexate. In cases of placenta percreta with bladder involvement, conservative treatment may be the optimal management. Regardless of the chosen option, the woman and her partner should be warned of the high risk of maternal complications related to an abnormally invasive placenta

Global patterns of moss diversity: taxonomic and molecular inferences

Taxonomic and molecular data were utilized to test the hypothesis that moss diversity is greatest near the equator. Species richness estimates from 86 taxonomic checklists representing global moss diversity do not support the hypothesis that, in general, mosses are more species-rich in the tropics than at higher latitudes

Phylogenetic significance of the rpoA loss in the chloroplast genome of mosses

A recent survey of arthrodontous mosses revealed that their chloroplast genome lacks the gene encoding the alpha subunit of the RNA polymerase (i.e., rpoA), and that at least in Physcomitrella patens the gene has been transferred to the nuclear genome. Subsequently the gene was recorded from the cytoplasmic genome in Takakia and Sphagnum. Here we extend the survey to representatives of all major lineages of mosses to determine when in the evolutionary history of the Bryophyta the loss took place. Amplifications using primers annealing to the flanking regions of the rpoA gene yield a product that contains the gene in Takakia, Sphagnum, Andreaea, Oedipodium, Polytrichaceae, and Buxbaumia. The gene is lacking in all arthrodontous mosses, including Diphyscium but also in both species of Tetraphis. Reconstruction of the transfer on the phylogeny of mosses suggests (a) that the rpoA gene was lost twice and (b) that the gene was lost after the divergence of Buxbaumiidae and prior to the divergence of Diphyscium from the remaining Bryopsida

Maximum-likelihood models for mapping genetic markers showing segregation distortion : 2. F2 populations

Dans la génération F2, la sélection naturelle des gamètes et des zygotes peut affecter les linkages génétiques. Une équation mathématique qui prend toutes les probabibilités de linkage en compte est développée. L'intégration des marqueurs génétiques dominants et codominants permet d'obtenir une courbe de probabilité asymptotique. La comparaison de l'utilité et de la précision des modèles montre que la prise en compte des marqueurs dominants seuls ne donne pas assez d'information sur le cas de distorsions de ségrégation. L'estimation de la fraction de recombinaisons entre les marqueurs codominants est peu affectée par la sélection, ce qui n'est pas le cas pour les marqueurs dominant

Multilocus-based phylogeny and species recognition within the cosmopolitan Peltigera neopolydactyla-dolichorhiza complex

The Peltigera neopolydactyla/dolichorhiza complex is broadly distributed, growing in boreal and temperate regions from northern Norway to southern Chile, as well as in tropical mountains. Observed morphotype and chemotype variation within this complex suggested the presence of multiple undescribed species. We inferred the phylogeny of Peltigera section Polydactylon with a special focus on the Peltigera neopolydactyla/dolichorhiza complex to determine the full breadth of this species complex, and to assess if taxa from different parts of the worlds but with similar morphological features share a most recent common ancestor. About 525 ITS sequences representing 104 distinct haplotypes were generated for representatives of Peltigera section Polydactylon. We selected a representative of each broadly defined phylotype for which three protein-coding loci: RPB1.1, b-tubulin and EFT2.1 were sequenced. Each of the three protein coding loci provided equivalent or more resolution and support than the ITS locus. The greatest proportion of significantly supported nodes across the tree resulted from β-tubulin alone. Many specimens identified as P. neopolydactyla and P. dolichorhiza are placed outside of this species complex. As currently defined both species represent polyphyletic assemblages of taxa including several potentially undescribed species. Our phylogenies suggest the presence of putatively new species within several complexes across the section.REVSYS: Phylogenetic revision of the lichen-genus Peltigera (Ascomycota): Disentangling cryptic speciation, phenotypic plasticity, and hybridization