Code de Conduite pour une Peche Responsable

La pêche, y compris l'aquaculture, apporte une contribution fondamentale à l'alimentation, à l'emploi, aux loisirs, au commerce et au bien-être économique des populations du monde entier, qu'il s'agisse des générations présentes ou futures, et devrait, par conséquent, être conduite de manière responsable. Le présent Code définit des principes et des normes internationales de comportement pour garantir des pratiques responsables en vue d'assurer effectivement la conservation, la gestion et le développement des ressources bioaquatiques, dans le respect des écosystèmes et de la biodiversité. Le Code reconnaît l'importance nutritionnelle, économique, sociale, environnementale et culturelle de la pêche et les intérêts de tous ceux qui sont concernés par ce secteur. Le Code prend en considération les caractéristiques biologiques des ressources et de leur environnement, ainsi que les intérêts des consommateurs et autres utilisateurs. Les Etats et tous ceux impliqués dans le secteur de la pêche sont encouragés à appliquer ce Code de manière effective. (PDF contains 53 pages)

What is the Code of Conduct for Responsible Fisheries?

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Qu'est-ce que le Code de Conduite pour une Peche Responsable?

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Two-magnon bound state causes ultrafast thermally induced magnetisation switching

There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime.

Exchange biased FeNi/FeMn bilayers with coercivity and switching field enhanced by FeMn surface oxidation

FeNi/FeMn bilayers were grown in a magnetic field and subjected to heat treatments at temperatures of 50 to 350 degrees C in vacuum or in a gas mixture containing oxygen. In the as-deposited state, the hysteresis loop of 30 nm FeNi layer was shifted. Low temperature annealing leads to a decrease of the exchange bias field. Heat treatments at higher temperatures in gas mixture result in partial oxidation of 20 nm thick FeMn layer leading to a nonlinear dependence of coercivity and a switching field of FeNi layer on annealing temperature. The maximum of coercivity and switching field were observed after annealing at 300 degrees C.

A delay model for noise-induced bi-directional switching

Many biological systems can switch between two distinct states. Once switched, the system remains stable for a period of time and may switch back to its original state. A gene network with bistability is usually required for the switching and stochastic effect in the gene expression may induce such switching. A typical bistable system allows one-directional switching, in which the switch from the low state to the high state or from the high state to the low state occurs under different conditions. It is usually difficult to enable bi-directional switching such that the two switches can occur under the same condition. Here, we present a model consisting of standard positive feedback loops and an extra negative feedback loop with a time delay to study its capability to produce bi-directional switching induced by noise. We find that the time delay in the negative feedback is critical for robust bi-directional switching and the length of delay affects its switching frequency.