Quelle place pour les adventices dans l’épidémiosurveillance ? Rapport au Comité National d’Epidémiosurveillance

La gestion des adventices est à juste titre considérée comme un frein majeur à l’adoption deméthodes intégrées de conduite des cultures peu dépendantes en produits phytosanitaires.Leur dynamique d’infestation se construisant sur plusieurs saisons culturales du fait du stock desemences dans le sol, les plantes adventices ne peuvent être gérées comme le seraient d’autresravageurs dépendant des seuls paramètres saisonniers pour déclencher leur épidémie. Pourautant notre groupe conclut que l’épidémiosurveillance des adventices peut être utile à unerationalisation des moyens de lutte. Elle peut permettre, sur le pas de temps court, d’optimiseren saison le choix tactique et le timing des interventions de tout ordre ayant un impact sur lesadventices et doit pour cela apparaître clairement dans les Bulletins de Santé du Végétal (BSV).Sa compilation sur plusieurs saisons permettra de mieux saisir l’évolution de la flore et depointer du doigt les facteurs responsables sous-jacents. Ceux-ci constituent autant d’éléments àintégrer dans l’analyse du risque et les préconisations stratégiques qui peuvent en découler. (...

Espaces-temps courbes par cristallisation de fibrés liquides

International audienceMotivated by the search for a Hamiltonian formulation of Einstein equations of gravity which depends in a minimal way on choices of coordinates, nor on a choice of gauge, we develop a multisymplectic formulation on the total space of the principal bundle of orthonormal frames on the 4-dimensional space-time. This leads quite naturally to a new theory which takes place on 10-dimensional manifolds. The fields are pairs of ((α,ω),ϖ)((α,ω),ϖ) , where (α,ω)(α,ω) is a 1-form with coefficients in the Lie algebra of the Poincaré group and ϖϖ is an 8-form with coefficients in the dual of this Lie algebra. The dynamical equations derive from a simple variational principle and imply that the 10-dimensional manifold looks locally like the total space of a fiber bundle over a 4-dimensional base manifold. Moreover this base manifold inherits a metric and a connection which are solutions of a system of Einstein–Cartan equations

Flexible links manipulators : from modelling to control

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Use of Alliaceae residues to control soil-borne pathogens

International audienceThe presence of large amounts of sulfur compounds in the organs of Allium species has lead to the suggestion that the residues of this plant family could be used in soil biofumigation. In this paper, we report the preliminary results of laboratory bioassays and field experiments that investigated the biofumigant effects of onion and leek residues. The active molecules in these Allium species were determined to be dimethyl disulfide (DMDS) and dipropyl disulfide (DPDS). The results show that onion by-products and DMDS not only had a high level of biofumigant activity, but also stimulated vegetative growth. In the field, when Allium by-products were incorporated into the soil, DPDS was frequently released and was detectable for up to one month afterwards. This treatment increased asparagus and strawberry productivity by 15-20%, a result that is comparable to those obtained using Brassica-based biofumigation. Given the concordance between the results of the bioassays and those of the preliminary field trials, onion by-products may have practical potential as new biofumigants and could be used as an alternative to methyl bromide. In the agronomic context, it is crucial to develop improved application techniques that reduce the quantity of onion by-products that need to be incorporated into soil

Impact of gene mutations on treatment response and prognosis of acute myeloid leukemia secondary to myeloproliferative neoplasms

International audienceAcute myeloid leukemias secondary (sAML) to myeloproliferative neoplasms (MPN) have variable clinical courses and outcomes, but remain almost always fatal. Large cohorts of sAML to MPN are difficult to obtain and there is very little scientific literature or prospective trials for determining robust prog-nostic markers and efficient treatments. We analyzed event-free survival (EFS) and overall survival (OS) of 73 patients with MPN who progressed to sAML, based on their epidemiological characteristics , the preexisting MPN, the different treatments received, the different prognostic groups and the responses achieved according to the ELN, and their mutational status determined by next-generation DNA sequencing (NGS). For 24 patients, we were able to do a comparative NGS analysis at both MPN and sAML phase. After acute transformation EFS and OS were respectively of 2.9 months (range: 0-48.1) and 4.7 months (range: 0.1-58.8). No difference in EFS or OS regarding the previous MPN, the ELN2017 prognostic classification, the first-line therapy or the response was found. After univariate analysis, three genes, TP53, SRSF2 and TET2, impacted pejoratively sAML prognosis at sAML time. In multivariate analysis, TP53 (P 5 .0001), TET2 (P 5 .011) and SRSF2 (P 5 .018) remained independent prognostic factors. Time to sAML transformation was shorter in SRSF2-mutated patients (51.2 months, range: 14.7-98) than in SRSF2-unmutated patients (133.8 months, range: 12.6-411.2) (P < .001). Conventional clinical factors (age, karyotype, ELN2017 prognostic classification, treatments received, treatments response, Allo-SCT.. .) failed to predict the patients' outcome. Only the mutational status appeared relevant to predict patients' prognosis at sAML phase

Genomic analysis of myeloproliferative neoplasms in chronic and acute phases

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