Subducted organic matter buffered by marine carbonate rules the carbon isotopic signature of arc emissions

Ocean sediments consist mainly of calcium carbonate and organic matter (phytoplankton debris). Once subducted, some carbon is removed from the slab and returns to the atmo- sphere as CO2 in arc magmas. Its isotopic signature is thought to reflect the bulk fraction of inorganic (carbonate) and organic (graphitic) carbon in the sedimentary source. Here we challenge this assumption by experimentally investigating model sediments composed of 13C-CaCO3 + 12C-graphite interacting with water at pressure, temperature and redox con- ditions of an average slab–mantle interface beneath arcs. We show that oxidative dissolution of graphite is the main process controlling the production of CO2, and its isotopic compo- sition reflects the CO2/CaCO3 rather than the bulk graphite/CaCO3 (i.e., organic/inorganic carbon) fraction. We provide a mathematical model to relate the arc CO2 isotopic signature with the fluid–rock ratios and the redox state in force in its subarc source

Brief Report: Normal Intestinal Permeability at Elevated Platelet Serotonin Levels in a Subgroup of Children with Pervasive Developmental Disorders in Curaçao (The Netherlands Antilles)

This study investigated the relationship between platelet (PLT) serotonin (5-HT) and intestinal permeability in children with pervasive developmental disorders (PDD). Differential sugar absorption and PLT 5-HT were determined in 23 children with PDD. PLT 5-HT (2.0–7.1 nmol/109 PLT) was elevated in 4/23 patients. None exhibited elevated intestinal permeability (lactulose/mannitol ratio: 0.008–0.035 mol/mol). PLT 5-HT did not correlate with intestinal permeability or GI tract complaints. PLT 5-HT correlated with 24 h urinary 5-hydroxyindoleacetic acid (5-HIAA; p = .034). Also urinary 5-HIAA and urinary 5-HT were interrelated (p = .005). A link between hyperserotonemia and increased intestinal permeability remained unsupported. Increased PLT 5-HT in PDD is likely to derive from increased PLT exposure to 5-HT. Longitudinal studies, showing the (in)consistency of abnormal intestinal permeability and PLT 5-HT, may resolve present discrepancies in the literature

Biocontrol of invasive carp : risks abound

No abstract available

Comparison between three methods for measurement of the back fat thickness in the pig

International audienc

Advanced systems Multicomponent LDV

Tire de : Lecture series VKI on laser velocimetry, Rhode-Saint-Genese (Belgium), June 10-14, 1991SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1991 n.89 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Caracterisation de la turbulence par velocimetrie laser

Communication to : AAAF - 35eme colloque d'aerodynamique appliquee, Lille (France), 22-24 mars 1999SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.1999 n.49 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc