New insights on the population genetic structure of the great scallop (Pecten maximus) in the English Channel coupling microsatellite data and demogenetic simulations.

International audienceThe great scallop (Pecten maximus) is a commercially important bivalve in Europe, particularly in the English Channel, where fisheries are managed at regional and local scales through the regulation of fishing effort. In the long term, knowledge about larval dispersal and gene flow between populations is essential to ensure proper stock management. Yet, previous population genetic studies have reported contradictory results. In this study, scallop samples collected across the main fishing grounds along the French and English coasts of the English Channel (20 samples with temporal replicates for three sites,n= 1059 individuals), and the population genetic structure was analysed using 13 microsatellite loci. Coupling empirical genetic data with demogenetic modelling based on a biophysical model simulating larval exchanges among scallop beds revealed a subtle genetic differentiation between south-west English populations and the rest of the English Channel, which was consistent with larval dispersal simulations. The present study provides a step forward in the understanding of great scallop population biology in the English Channel, underlining the fact that even in a context of potentially high gene flow and recent divergence times since the end of the last glacial maximum, weak but significant spatial genetic structure can be identified at a regional scale

Modélisation des marées et des surcotes dans les Pertuis Charentais

The variations of sea level during strong storm surges affect the coast provoking the severe flooding. The aim of this thesis is to provide a better understanding, using numerical modelisation (TELEMAC), of interactions between storm surge / tide / wave / wind in the generation and propagation of storm surges and tidal waves in the Pertuis Charentais, which, by a complex coastal line and shallow waters, are a site of great interest for this type of study. In this thesis, we have demonstrated that taking into account of these interactions is necessary for any model which aims to forecast precisely the strorm surges in the Pertuis Charentais.Les variations du niveau marin lors des grandes tempêtes affectent le littoral en provoquant de sévères inondations. L'objectif de cette thèse est d'apporter, grâce à la modélisation numérique (chaîne TELEMAC), une meilleure compréhension des phénomènes d'interaction entre surcote / marée / houle / vent dans la génération et la propagation des surcotes et des raz de marée dans les Pertuis Charentais, qui, grâce à une ligne de côte complexe et des faibles profondeurs, représentent un grand intérêt pour ce type d'étude. Dans cette thèse, nous avons démontré que la prise en compte de ces interactions est indispensable pour un modèle qui prétend à une prédiction précise des surcotes dans les Pertuis Charentais

The Emerging Function of PKCtheta in Cancer

Protein Kinase C theta (PKCθ) is a serine/threonine kinase that belongs to the novel PKC subfamily. In normal tissue, its expression is restricted to skeletal muscle cells, platelets and T lymphocytes in which PKCθ controls several essential cellular processes such as survival, proliferation and differentiation. Particularly, PKCθ has been extensively studied for its role in the immune system where its translocation to the immunological synapse plays a critical role in T cell activation. Beyond its physiological role in immune responses, increasing evidence implicates PKCθ in the pathology of various diseases, especially autoimmune disorders and cancers. In this review, we discuss the implication of PKCθ in various types of cancers and the PKCθ-mediated signaling events controlling cancer initiation and progression. In these types of cancers, the high PKCθ expression leads to aberrant cell proliferation, migration and invasion resulting in malignant phenotype. The recent development and application of PKCθ inhibitors in the context of autoimmune diseases could benefit the emergence of treatment for cancers in which PKCθ has been implicated

The Emerging Function of PKCtheta in Cancer

Protein Kinase C theta (PKCθ) is a serine/threonine kinase that belongs to the novel PKC subfamily. In normal tissue, its expression is restricted to skeletal muscle cells, platelets and T lymphocytes in which PKCθ controls several essential cellular processes such as survival, proliferation and differentiation. Particularly, PKCθ has been extensively studied for its role in the immune system where its translocation to the immunological synapse plays a critical role in T cell activation. Beyond its physiological role in immune responses, increasing evidence implicates PKCθ in the pathology of various diseases, especially autoimmune disorders and cancers. In this review, we discuss the implication of PKCθ in various types of cancers and the PKCθ-mediated signaling events controlling cancer initiation and progression. In these types of cancers, the high PKCθ expression leads to aberrant cell proliferation, migration and invasion resulting in malignant phenotype. The recent development and application of PKCθ inhibitors in the context of autoimmune diseases could benefit the emergence of treatment for cancers in which PKCθ has been implicated

Le projet Hydrographie/Robotique au Lac de Guerlédan

International audienc

Assessing the Influence of Changes in Shoreface Morphology since the 19th Century on Nearshore Hydrodynamics and Shoreline Evolution in Northern France: A Modeling Approach

The shoreface off the coast of northern France is characterized by the presence of numerous tidal sand banks, forming linear shore-parallel or slightly oblique massive sand bodies. Digitization of historic hydrographic field sheets from the French Hydrographic Service (Shorn) archives enabled to produce Digital Elevation Models (DEMs) of the seabed morphology at different dates since the early 19th century. Our analyses of bathymetry changes based on differential DEMs showed significant morphological variations across the shoreface near Calais during the 19th and 20th centuries, which are largely due to changes in nearshore sand bank morphology and position. Sand bank mobility can be partially explained by tidal current asymmetry, inducing an elongation and an alongshore migration of this sand body in the direction of the net residual tidal current. Observed changes in shoreface and nearshore morphology attempt to be related with possible variations in hydrodynamics, this paper presenting the results obtained on tidal currents. TELEMAC-2D model was used to simulate 2D velocity field and water depth during a spring and neap tidal cycle over bathymetry grids based on historical bathymetric soundings. Depending on the bathymetric setting, modeling of tidal residual currents revealed notable increases or decreases in residual current velocity during distinct time periods, particularly in nearshore areas, which may lead to seabed erosion where current strengthening is observed through titne or conversely to sediment accumulation in areas of decreasing current velocity. These results are consistent with the shoreline changes that occurred during the 20th century, with a correspondence between nearshore areas of decreasing (or increasing) residual current velocity and adjacent shorelines that were affected by seaward progradation (or erosion), suggesting strong links between changes in seabed morphology over the shoreface and shoreline evolution

Influence of shoreface morphological changes since the 19th century on nearshore hydrodynamics and shoreline evolution in Wissant Bay (northern France)

International audienceLocated at the southern approaches to the North Sea, the Wissant Bay has had the most rapidly eroding shoreline in mainland France in recent decades. Using historical bathymetries spanning the second half of the 19th century to the present, an analysis of the long-term coastal morphological changes and evolution of a prominent sand bank (Line bank), extending across the bay, was carried out. A period of overall seabed erosion with a width-reduction of the Line bank; a deepening of the channel between the Line bank and the coast; and a lowering of the foreshore have been ongoing since the middle of the 20th century. This phase followed a period of channel infill in the western part of Wissant Bay in the early 20th century. Numerical modelling of wave propagation and tidal circulation was performed using the TELEMAC suite of models to get some insights into the influence of these bathymetry changes on coastal hydrodynamics. Two seabed configurations were identified revealing a contrasting hydrodynamic circulation. An erosional one induces an acceleration of tidal currents and an increase in wave height. Conversely, accumulation leads to an hydrodynamic regime weakening with a decrease in current velocity and to more wave energy dissipation in the nearshore. This study highlights the role of morphological feedbacks between nearshore morphology and coastal hydrodynamics. The identification of these feedbacks mechanisms at a historical time scale is important to assess potential drivers of coastal changes

Modélisation des marées et des surcotes dans les Pertuis charentais

Les variations du niveau marin lors des grandes tempêtes affectent le littoral en provoquant de sévères inondations. L objectif de cette thèse est d apporter, grâce à la modélisation numérique (chaîne TELEMAC), une meilleure compréhension des phénomènes d interaction entre surcote / marée / houle / vent dans la génération et la propagation des surcotes et des raz de marée dans les Pertuis Charentais, qui, grâce à une ligne de côte complexe et des faibles profondeurs, représentent un grand intérêt pour ce type d étude. Dans cette thèse, nous avons démontré que la prise en compte de ces interactions est indispensable pour un modèle qui prétend à une prédiction précise des surcotes dans les Pertuis CharentaisThe variations of sea level during strong storm surges affect the coast provoking the severe flooding. The aim of this thesis is to provide a better understanding, using numerical modelisation (TELEMAC), of interactions between storm surge / tide / wave / wind in the generation and propagation of storm surges and tidal waves in the Pertuis Charentais, which, by a complex coastal line and shallow waters, are a site of great interest for this type of study. In this thesis, we have demonstrated that taking into account of these interactions is necessary for any model which aims to forecast precisely the strorm surges in the Pertuis CharentaisLA ROCHELLE-BU (173002101) / SudocSudocFranceF

Assessing the Influence of Changes in Shoreface Morphology since the 19th Century on Nearshore Hydrodynamics and Shoreline Evolution in Northern France: A Modeling Approach

International audienceThe shoreface off the coast of northern France is characterized by the presence of numerous tidal sand banks, forming linear shore-parallel or slightly oblique massive sand bodies. Digitization of historic hydrographic field sheets from the French Hydrographic Service (Shorn) archives enabled to produce Digital Elevation Models (DEMs) of the seabed morphology at different dates since the early 19th century. Our analyses of bathymetry changes based on differential DEMs showed significant morphological variations across the shoreface near Calais during the 19th and 20th centuries, which are largely due to changes in nearshore sand bank morphology and position. Sand bank mobility can be partially explained by tidal current asymmetry, inducing an elongation and an alongshore migration of this sand body in the direction of the net residual tidal current. Observed changes in shoreface and nearshore morphology attempt to be related with possible variations in hydrodynamics, this paper presenting the results obtained on tidal currents. TELEMAC-2D model was used to simulate 2D velocity field and water depth during a spring and neap tidal cycle over bathymetry grids based on historical bathymetric soundings. Depending on the bathymetric setting, modeling of tidal residual currents revealed notable increases or decreases in residual current velocity during distinct time periods, particularly in nearshore areas, which may lead to seabed erosion where current strengthening is observed through titne or conversely to sediment accumulation in areas of decreasing current velocity. These results are consistent with the shoreline changes that occurred during the 20th century, with a correspondence between nearshore areas of decreasing (or increasing) residual current velocity and adjacent shorelines that were affected by seaward progradation (or erosion), suggesting strong links between changes in seabed morphology over the shoreface and shoreline evolution