From mechanical to chemical impact of anchoring in seagrasses: the premises of anthropogenic patch generation in Posidonia oceanica meadows

Intensive anchoring of leisure boats in seagrass meadows leads to mechanical damages. This anthropogenic impact creates bare mat patches that are not easily recolonized by the plant. Several tools are used to study human impacts on the structure of seagrass meadows but they are not able to assess the indirect and long term implication of mechanical destruction. We chose to investigate the possible changes in the substrate chemistry given contrasted boat impacts. Our observations show that hydrogen sulfide concentrations remain high at 15 and 20 m depth (42.6 µM and 18.8 µM) several months after the highest period of anchoring during the summer. Moreover, our multidisciplinary study reveals that anchoring impacts of large boats at 15 and 20 m depth can potentially change the seascape structure. By taking into account both structural and chemical assessments, different managing strategies must be applied for coastal areas under anthropogenic pressures.STARE-CAPME

Advocacy for Multi Mobile Coil Magnetic Manipulation in Active Digestive Endoscopy.

International audienceTraditional techniques of endoscopy based on flexible endoscopes are fairly reliable but poorly tolerated by patients and do not give access to the small bowel. Magnetic fields have been shown usable for manipulating endoscopic capsules, either using static coils with varying currents or mobile permanent magnets. In this short paper, we propose a novel approach which combines electromagnetic and kinematic effects and outline our research

Evaluation of an air spinning process to produce tailored biosynthetic nanofiber scaffolds

We optimised the working parameters of an innovative air spinning device to produce nanofibrous polymer scaffolds for tissue engineering applications. Scanning electron microscopy was performed on the fibre scaffolds which were then used to identify various scaffold morphologies based on the ratio of surface occupied by the polymer fibres on that covered by the entire polymer scaffold assembly. Scaffolds were then produced with the spinning experimental parameters, resulting in 90% of fibres in the overall polymer construct, and were subsequently used to perform a multiple linear regression analysis to highlight the relationship between nanofibre diameter and the air spinning parameters. Polymer solution concentration was deemed as the most significant parameter to control fibre diameter during the spinning process, despite interactions between experimental parameters. Based on these findings, viscosity measurements were performed to clarify the effect of the polymer solution property on scaffold morphology

Measuring fish activities as additional environmental data during a hydrographic survey with a multi-beam echo sounder

International audienceThe modern multi-beam echo sounders (MBES) are advanced instrumentation for active underwater acoustic surveys that can be boarded on oceanic vessels as well on light crafts. Although their versatility allows scientists to perform various environmental studies, their potential is seldom fully exploited. A single data acquisition cruise is not only able to display the seabed backscatter, but also provide an estimation of the fish activities from an underwater site thanks to water column imagery. This work is aiming at developing some (automatic) signal processing techniques to detect, analyse and classify objects observed in the water column with a focus on fish activities to provide fish accumulation and classification but also some comparative analyses along with the seafloor classification

Modélisation numérique 2-D du jet de rive

Nous présentons les résultats de simulations Navier-Stokes/VOF (code AQUILON – TREFLE) de l'écoulement air/eau d'un jet de rive, qui est l'écoulement final généré par une vague déferlante lorsqu'elle arrive sur le haut d'une plage. La partie amont du jet de rive est d'abord validée par la simulation de la propagation d'un ressaut hydraulique sur fond plat. Nous étudions ensuite la transformation d'un ressaut en jet de rive sur une plage inclinée. Les résultats en termes de profils de surface libre et de vitesse de propagation du mascaret et de la nappe de swash, comparés aux mesures par Yeh et al. (1989), montrent une bonne correspondance