New stable QTLs for berry weight do not colocalize with QTLs for seed traits in cultivated grapevine (Vitis vinifera L.)

International audienceBACKGROUND: In grapevine, as in other fruit crops, fruit size and seed content are key components of yield and quality; however, very few Quantitative Trait Loci (QTLs) for berry weight and seed content (number, weight, and dry matter percentage) have been discovered so far. To identify new stable QTLs for marker-assisted selection and candidate gene identification, we performed simultaneous QTL detection in four mapping populations (seeded or seedless) with various genetic backgrounds. RESULTS: For berry weight, we identified five new QTLs, on linkage groups (LGs) 1, 8, 11, 17 and 18, in addition to the known major QTL on LG 18. The QTL with the largest effect explained up to 31% of total variance and was found in two genetically distant populations on LG 17, where it colocalized with a published putative domestication locus. For seed traits, besides the major QTLs on LG 18 previously reported, we found four new QTLs explaining up to 51% of total variance, on LGs 4, 5, 12 and 14. The previously published QTL for seed number on LG 2 was found related in fact to sex. We found colocalizations between seed and berry weight QTLs only for the major QTL on LG 18 in a seedless background, and on LGs 1 and 13 in a seeded background. Candidate genes belonging to the cell number regulator CNR or cytochrome P450 families were found under the berry weight QTLs on LGs 1, 8, and 17. The involvement of these gene families in fruit weight was first described in tomato using a QTL-cloning approach. Several other interesting candidate genes related to cell wall modifications, water import, auxin and ethylene signalling, transcription control, or organ identity were also found under berry weight QTLs. CONCLUSION: We discovered a total of nine new QTLs for berry weight or seed traits in grapevine, thereby increasing more than twofold the number of reliable QTLs for these traits available for marker assisted selection or candidate gene studies. The lack of colocalization between berry and seed QTLs suggests that these traits may be partly dissociated

A multidisciplinary study of a syntectonic pluton close to a major lithospheric-scale fault: relationships between the Montmarault granitic massif and the Sillon Houiller Fault in the Variscan French Massif Central. Part II: Gravity, aeromagnetic investigations and 3D geologic modeling.

International audienceNew gravity and aeromagnetic investigations have been carried out to understand the emplacement mechanisms of a granitic pluton and the relationships with a nearby lithospheric-scale fault. This paper concerns the second part of a methodological multidisciplinary study and complements previous geochronologic and Anisotropy of Magnetic Susceptibility (AMS) studies on the same pluton. In the northern part of the Variscan French Massif Central (FMC), the Montmarault massif crops out along the Sillon Houiller Fault (SHF). Bouguer and aeromagnetic anomaly maps imply thickening of the pluton along the SHF and suggest laccolitic spreading northwestwards. Based on petrophysical measurements, direct 2D joint gravity and magnetic modeling has been performed along 10 cross-sections. In order to quantitatively constrain the 3D pluton geometry and its relationships with surrounding geologic units, these geophysical cross-sections, new structural information (field and AMS measurements) and petrophysical data have been integrated into a regional 3D geological and geophysical model. Altogether, the results obtained from geochronology, petro-magnetic fabrics (Part I), gravity and aeromagnetic investigations as well as 3D modeling (Part II), demonstrate that the Montmarault pluton was emplaced during the Namurian period along the SHF. Our results further show that, at that time, in response to a NW-SE regional extension, if the SHF existed, it behaved as a normal fault. Mylonites attesting for synmagmatic normal motion on the northeastern part of the Montmarault pluton strengthen this tectonic scheme. During the Late Carboniferous, the FMC experienced NE-SW extension along the SHF by 80 km of brittle left lateral wrench offset. This second tectonic event is well recorded in the Stephanian coal basins which were formed along NW- SE listric brittle faults and constrain the present-day shape of the Montmarault pluton

Transpressional tectonics and Carboniferous magmatism in the Limousin, Massif Central, France: Structural and ⁴⁰Ar/³⁹Ar investigations

New structural, microstructural, and 40Ar/39 Ar data from the NW Massif Central (France) provide additional constraints on the timing and tectonic setting of late Variscan granite magmatism. Previous studies had emphasized the role of late orogenic extension in the emplacement of granite plutons in the Limousin region. In contrast, the new data set is consistent with syntectonic emplacement of magma in a dextral simple shear active from 350 to 300 Ma in a transpressional regime. As an alternative hypothesis to late orogenic extension, we propose that magmas migrated into tensional bridges between active P shears associated with a lithospheric shear zone comparable to a pop-up structure. The Galician region, in the western end of the Ibero-Armorican tectonic arc, exhibits major left-lateral ductile shear zones which can be interpreted as conjugate structures to the Limousin and Armorican shear zones. Copyright 2007 by the American Geophysical Union

Extensional ductile tectonics of the Sioule metamorphic series (Variscan French Massif Central)

International audienceIn the Northern part of the Variscan French Massif Central, the Sioule series, from top to bottom, consists of a pre-Viséan granite, migmatite, gneiss and mica schist. Two ductile deformations have been recognized. The earlier phase is characterized by a north-east-south-west trending stretching lineation; the second phase, characterized by a north-west-south-east trending mineral, stretching and crenulation lineation, is better marked in the lower mica schist part than in the upper granito-gneissic part. This second phase occurred during retrogression of the metamorphic rocks; related shear criteria indicate a top to the south-west shear. The Namurian-Westphalian magmatic bodies such as the Echassières leucogranite, Pouzol-Servant microgranite and numerous north-east -south-west trending microgranite dykes are emplaced in extensional fractures related to the same north-west-south-east maximum stretching direction. The asymmetrical shapes of the two granitic massifs indicate that they intruded towards the south-east. The synkinematic retrogression of the metamorphic rocks, the shape of the magmatic bodies and a re-examination of the numerous available data support the interpretation that the deformation is due to the extensional tectonic regime related to the Variscan crustal re-quilibration. This interpretation is in agreement with the correlation of the Sioule series with the Chavanon series. The two series belong to a unique tectono-metamorphic unit left-laterally offset by the Stephanian motion of the Sillon Houiller fault. This study also shows that the Sillon Houiller did not play a significant part during the Namurian-Westphalian extensional tectonics of the Massif Central

Cost-effectiveness of colorectal cancer screening with computed tomography colonography or fecal blood tests

International audienceObjective: To assess the cost-effectiveness of colorectal cancer screening using computed tomography colonography (CTC) and immunological fecal occult blood test (iFOBT). : CTC and iFOBT strategies were compared with Nn screening or guaiac FOBT (gFOBT) using Markov modeling. CTC was proposed at 50, 60, and 70 years, whereas gFOBT and iFOBT were performed every 2 years beginning at 50 years until 74 years of age with a 30-year time horizon. We calculated incremental cost-effectiveness ratios and efficiency ratios (ERs). Then, we performed univariate and probabilistic sensitivity analyses. : With gFOBT as reference, colorectal cancer prevention rate was 18% for CTC and 11% for iFOBT. The incremental cost-effectiveness ratio of CTC and iFOBT were respectively 3204 and 5458€ per life years gained (LYG), the ER for CTC was 0.22 and the ER for iFOBT was 2.08 colonoscopies per LYG. Cost-effectiveness results were sensitive to CTC cost. In the probabilistic sensitivity analysis, compared with CTC, iFOBT strategy was cost-effective for 84.6% of simulations when we assumed a willingness to pay (WTP) of 20 000€/LYG. Conclusion: CTC requires substantially less colonoscopies than iFOBT and is cost-effective for low values of WTP. However, iFOBT is the preferred screening strategy for a WTP greater than 6207€/LYG

Bases théoriques des études coût-efficacité en médecine

The objective of this study was to explain foundations of cost-effectiveness analysis and to describe indicators and variables commonly used in public health decisions

Homogénéisation par la méthode des formes moyennes équivalentes dans le milieu biphasé

A theory is presented, extending Ondracek's derivation which is normally restricted to oblate and prolate spheroids, to the case of any kind of ellipsoid representing the texture of the aggregate as an average equivalent shape (A.E.S.). With such a theory, the effective conductivity of any rock can be calculated from the conductivities of rock forming minerals, from the volume fractions, the lengths and orientations of the semi-axes a, b, c of the average equivalent ellipsoid determined by quantitative microscopy.On peut calculer les conductivités (thermique, électrique, etc.) des roches à partir des conductivités et des fractions volumiques des minéraux constitutifs, de la forme des grains représentée par un « ellipsoïde moyen équivalent » (E.M.E.), et de leur orientation moyenne. La théorie présentée étend aux ellipsoïdes quelconques la théorie d'Ondracek jusqu'ici limitée aux ellipsoïdes de révolution