Excursion Ardèche (13-15 mai 1977)

International audienceLes massifs hercyniens ont été longuement érodés pendant le Permien. Des sédiments gréseux et dolomitiques du Trias se sont ensuite déposés sur une plate-forme uniformisée et peu profonde. Toutefois la monotonie de l'ensemble n'excluait pas l'influence de reliefs sous-marins d'origine hercynienne. Les termes liasiques montrent à la fois une épaisseur réduite et des variations de faciès dues à une plate-forme sous-marine instable. Les influences obéissent d'une part à la direction cévenole (NE-SW) et d'autre part à une direction qui lui est orthogonale. A partir du Callovien les conditions deviennent homogènes dans l'ensemble de la région et paraissent le rester jusque dans le Jurassique terminal

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Campagne Biocal: Environnement bathyal actuel et recent aux abords de la Nouvelle Caledonie

A zoological survey of all macrofauna of benthic Invertebrates has been made along the slopes. New taxa of all taxonomic ranks are abundant. High faunal specific diversity and originality is obvious to all taxonomists. It is worth to mention that since the "Challenger" expedition over a century ago, the whole south-western Pacific region has been kept away from the great deep-sea research vessels routes. The study of both the BIOCAL collections and all the others from further cruises around New Caledonia is insured to provide new data to understanding the biogeography and evolution of the deep sea fauna

ASTRONOMICAL CONTROL OF CARBONATE RECORD IN THE LOWER CRETACEOUS OF THE VOCONTIAN BASIN (SE FRANCE)

International audienceA study of variations in carbonate productivity, quantified by calcium carbonate content for a Valanginian-Hanterivian interval, is presented from the Angles-Vergons series (Vocontian basin). Spectral analysis techniques reveal the presence of significant carbonate cycles linked to cyclic variations of the Earth's orbit, The results suggest that the obliquity cycle is the most clearly defined signal whereas the presence of carbonate cycles related to the precession signal is less distinct. The transition from limestone-dominated alternations to marl-dominated alternations is characterized both by an increase of sedimentation rate and a change from the precession cycle being the dominant forcing factor in the calcareous part to the predominance of the obliquity cycle in the marly part. An orbitally calibrated chronology is presented for the Valanginian-Hanterivian interval based on the identification of carbonate cycles

ASTRONOMICAL CONTROL OF CARBONATE RECORD IN THE LOWER CRETACEOUS OF THE VOCONTIAN BASIN (SE FRANCE)

International audienceA study of variations in carbonate productivity, quantified by calcium carbonate content for a Valanginian-Hanterivian interval, is presented from the Angles-Vergons series (Vocontian basin). Spectral analysis techniques reveal the presence of significant carbonate cycles linked to cyclic variations of the Earth's orbit, The results suggest that the obliquity cycle is the most clearly defined signal whereas the presence of carbonate cycles related to the precession signal is less distinct. The transition from limestone-dominated alternations to marl-dominated alternations is characterized both by an increase of sedimentation rate and a change from the precession cycle being the dominant forcing factor in the calcareous part to the predominance of the obliquity cycle in the marly part. An orbitally calibrated chronology is presented for the Valanginian-Hanterivian interval based on the identification of carbonate cycles

Periodicities of carbonate cycles in the Valanginian of the Vocontian Trough: a strong obliquity control

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