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International audience; Abstract The Mediterranean corn borer (Sesamia nonagrioides, Noctuidae, Lepidoptera) is a major pest of maize in Europe and Africa. Here, we report an assembly of the nuclear and mitochondrial genome of a pool of inbred males and females third-instar larvae, based on short- and long-read sequencing. The complete mitochondrial genome is 15,330 bp and contains all expected 13 and 24 protein-coding and RNA genes, respectively. The nuclear assembly is 1021 Mb, composed of 2553 scaffolds and it has an N50 of 1105 kb. It is more than twice larger than that of all Noctuidae species sequenced to date, mainly due to a higher repeat content. A total of 17,230 protein-coding genes were predicted, including 15,776 with InterPro domains. We provide detailed annotation of genes involved in sex determination (doublesex, insulin-like growth factor 2 mRNA-binding protein, and P-element somatic inhibitor) and of alpha-amylase genes possibly involved in interaction with parasitoid wasps. We found no evidence of recent horizontal transfer of bracovirus genes from parasitoid wasps. These genome assemblies provide a solid molecular basis to study insect genome evolution and to further develop biocontrol strategies against S. nonagrioides.

International audience; Les dunes côtières sont des corps sédimentaires caractéristiques des côtes meubles sableuses. Dans un contexte d’érosion des littoraux, l’évolution du pied de dune est souvent le marqueur privilégié du recul du trait de côte. Pour assurer la mise en sécurité des personnes et des biens, les risques associés aux phénomènes d’érosions littorales sont pris en compte par les autorités dans le cadre des Plans de Prévention des Risques Littoraux (PPRL). A la suite des phénomènes catastrophiques survenus lors de la tempête Xynthia (2010), des dispositions ont été prises pour revoir, améliorer et compléter les PPRL. L’érosion des côtes meubles est considérée par le nouveau guide méthodologique pour les plans de prévention des risques littoraux (MEDDE, 2014) comme un aléa fort dans une zone de recul du trait de côte à 100 ans. Ce recul correspond à une évolution sur le long terme du trait de côte, observable à l’échelle de plusieurs décennies. Mais, dans le cas des côtes sableuses, la variabilité interannuelle peut être forte et rendre difficile l’observation d’évolutions claires du trait de côte sur le long terme, de plus, l’impact d’un évènement tempétueux majeur ou d’une série de tempêtes rapprochées (comme durant l’hiver 2013-2014) peut modifier considérablement les tendances locales. Ainsi dans la nouvelle démarche des PPRL, la largeur de la zone d’aléa à 100 ans est caractérisée par la prise en compte du taux de recul moyen annuel (Tx) et d’un paramètre Lmax, correspondant à la valeur du recul du trait de côte consécutif à un évènement tempétueux majeur.En partenariat avec la Direction Générale des Risques et Prévention du MEEM, le BRGM réalise un travail méthodologique sur la détermination de ce paramètre Lmax pour les secteurs de dunes littorales. Dans un premier temps, ce paramètre peut être estimé par le recueil d’informations liées à des évènements historiques, mais des mesures plus spécifiques réalisées « post-tempête » sur le haut de plage et le front dunaire apparaissent également indispensables. En l’absence d’observations ou de mesures dans les bassins de risques, la mise au point de formules empiriques peut constituer une alternative, comme cela est réalisé aux Etats-Unis (méthode FEMA), sur la base de nombreuses observation de terrain, et aux Pays-Bas, à partir d’expériences en canal à houle (méthode DUROS). Les perspectives d’utilisation de modèles morphodynamiques spécifiques (XBeach) sont également envisagées.

International audience; Dune breaching can play a significant role in flooding events, as illustrated for instance by the Xynthia event which hit the French Atlantic coast in February 2010. The presentation will focus on the breaches which occurred on the dune of Les Boucholeurs site (South of La Rochelle, France) during Xynthia. To investigate the morphological changes of the dune system induced by the hydrodynamical and morphodynamical processes, we use the XBeachmorphodynamical model (Unesco-IHE, Delft University and Deltares,Roelvink et al, 2009). The model results show that the morphological impacts were mainly due to the dune system overflow at flood and ebb tides.In this modeling experiment, only the locally generated infragravity waves were taken into account. These local infragravity waves have a negligible effect on dune breaching. Additional computations at the scale of the Pertuis show which infragravity waves are neglected in the local computations. In addition,a sensitivity analysis to the initial topography data is carried out to assess if the modeled breaches locations are determined by the initial topography structure.

National audience

The design of catenary risers, riser towers, and export lines is key to oil and gas production in the deep ocean. Winds, waves, surface currents and current profiles are essential inputs to the design of these riser systems. With regards to current loading, the variety and abundance of current profiles can make it difficult to determine which profiles are most appropriate for determining extreme and fatigue loading on risers. The choices become increasingly difficult on the frontier of deepwater oil and gas developments as risers are increasingly being required to successfully operate in harsher environments and deeper water. However, longer and more detailed current measurements from in-situ deployments continue to become available. Two or three year current profile records are now common. In order to progress in the specification of current profiles and in the methodologies of using these profiles in the riser design, four oil & gas companies, BP Exploration Operating Company Limited, PETRÓLEO BRASILEIRO S.A. - PETROBRAS, Statoil ASA and TOTAL E&P Recherche Développement SAS, have funded the WACUP project (Worldwide Approximations of Current Profiles). The first objective of the WACUP project is to establish best practices for reducing large current profile databases into a smaller, representative set of profiles that can be used for designing risers. Three techniques have been compared in their ability in reducing measured in-situ databases: Empirical Orthogonal Function (EOF), Self Organizing Maps (SOM) and classical Current Profile Characterisation (CPC). For Vortex Induced Vibration (VIV) fatigue analysis we evaluate the skill of these three techniques in estimating VIV damage to a Steel Catenary Riser (SCR). Our measure of skill is the comparison of the results from the reduced data sets with results from the complete database. The standard techniques are modified, improving the accuracy of the database reduction. We recommend that any of these techniques can be made suitable for concept selection or preliminary engineering, but it may be desirable to run the full set of Gold Standard profiles for full detailed structural design. The second objective is to better understand the means to deal with extreme current profiles, in one part for fatigue damage and in another part for static loads analyses, to compare to traditional methods and to propose, if necessary, better practices. For fatigue, due to the complexity of the relation between current profile shape and damage, extrapolation on Gold Standard damage is the only way to produce quality n-year damage return values. Concerning extreme static response, the first analyses show that CCA profiles, used in exhaustive directions, produce realistic n-year return values. The ability of the available numerical current models to complement the in-situ measurements is also assessed. Models are superior to measurements for providing a large scale regional interpretation of key oceanographic processes. They can also be used to cost-effectively quantify spatial variability in the current regime. However they must be properly validated and calibrated before use in any engineering application. The primary source of data for characterisation of current profiles in riser design remains full water column, site specific, in-situ measurement.

The design of catenary risers, riser towers, and export lines is key to oil and gas production in the deep ocean. Winds, waves, surface currents and current profiles are essential inputs to the design of these riser systems. With regards to current loading, the variety and abundance of current profiles can make it difficult to determine which profiles are most appropriate for determining extreme and fatigue loading on risers. The choices become increasingly difficult on the frontier of deepwater oil and gas developments as risers are increasingly being required to successfully operate in harsher environments and deeper water. However, longer and more detailed current measurements from in-situ deployments continue to become available. Two or three year current profile records are now common. In order to progress in the specification of current profiles and in the methodologies of using these profiles in the riser design, four oil & gas companies, BP Exploration Operating Company Limited, PETRÓLEO BRASILEIRO S.A. - PETROBRAS, Statoil ASA and TOTAL E&P Recherche Développement SAS, have funded the WACUP project (Worldwide Approximations of Current Profiles). The first objective of the WACUP project is to establish best practices for reducing large current profile databases into a smaller, representative set of profiles that can be used for designing risers. Three techniques have been compared in their ability in reducing measured in-situ databases: Empirical Orthogonal Function (EOF), Self Organizing Maps (SOM) and classical Current Profile Characterisation (CPC). For Vortex Induced Vibration (VIV) fatigue analysis we evaluate the skill of these three techniques in estimating VIV damage to a Steel Catenary Riser (SCR). Our measure of skill is the comparison of the results from the reduced data sets with results from the complete database. The standard techniques are modified, improving the accuracy of the database reduction. We recommend that any of these techniques can be made suitable for concept selection or preliminary engineering, but it may be desirable to run the full set of Gold Standard profiles for full detailed structural design. The second objective is to better understand the means to deal with extreme current profiles, in one part for fatigue damage and in another part for static loads analyses, to compare to traditional methods and to propose, if necessary, better practices. For fatigue, due to the complexity of the relation between current profile shape and damage, extrapolation on Gold Standard damage is the only way to produce quality n-year damage return values. Concerning extreme static response, the first analyses show that CCA profiles, used in exhaustive directions, produce realistic n-year return values. The ability of the available numerical current models to complement the in-situ measurements is also assessed. Models are superior to measurements for providing a large scale regional interpretation of key oceanographic processes. They can also be used to cost-effectively quantify spatial variability in the current regime. However they must be properly validated and calibrated before use in any engineering application. The primary source of data for characterisation of current profiles in riser design remains full water column, site specific, in-situ measurement.