Nuxe (France)

For over two centuries, trawling fisheries have operated blindly; catches could not be known until onboard. These activities, which represents over half of seafood protein supply and of fishermen incomes, worldwide, are facing increasing societal pressure for their impacts on the ecosystem and their greenhouse gas emissions. Yet as of today, no alternative exists to maintain the same levels of production while reducing the impacts on the species welfare and ecosystems. We here demonstrate that previously blind trawling activities can now be turned into informed fishing, by developing a trawl system that can automatically detect and exclude bycatch species in real-time, using artificial intelligence (AI). The Game of Trawls system was achieved by coupling acoustic communication, actuators, embedded computer vision and AI trained to recognize both targeted species and unwanted species to release, in real-time. Full size trials were conducted in lab and are now being tested at sea to demonstrate the proof of concept that trawls catch can be monitored and exclusion devices triggered autonomously without human interaction. Several limits remain, in particular with the robustness of species detection by the AI, but these applied technological developments illustrate how wisely operated AI applications may help reaching a sustainable exploitation of marine resources and improving welfare of unwanted catches, offering a new step towards precision fishing.

Abstract We investigate the various types of degeneracy lifting, related to different forms of the Lifschitz invariants, which can arise in the energy dispersion curve, and determine the possible onset of one or several incommensurate phases. Necessary symmetry conditions are indicated for the occurence of “conical” points which correspond to an isotropic k dependence in a plane. Various types of these points are distinguished, and it is pointed out that conical points, which occur in the tetragonal, trigonal, and hexagonal space groups, are associated to modulated phases having lower superspace symmetries than when the modulation is along the third fourth, or sixth order axis.

Abstract We present a microscopic model of the first order phase transition of VO2, which incorporates both electron-electron and electron-lattice interactions. At a given temperature, the free energy is a function of two variational parameters: the static amplitude of a zone boundary normal mode, which is the crystallographic order parameter, and the mean amplitude of local magnetic moments, which describes electron-electron correlations. The phase transition is found to be first order, and is driven by electron-electron correlations which, above a critical value, stabilize the distorted insulating phase.