Why not? Decrypting social attitudes toward European aquaculture: An updated policy perspective for an old problem.

In some food production systems, sustainability and acceptability are considered umbrella concepts that can be assessed through a combination of criteria and indicators. After a remarkable and somewhat chaotic development in the early 1990s, European aquaculture has been evolving in both scientific and policy domains to improve, and to prove, its sustainability. The updated review of the literature and policy framework presented in this article highlights gaps in European studies, addressing mostly concerns over environmental impacts and food safety and less over economic impacts on other coastal activities or the effects on social values and local traditions. The analysis of the legislative framework demonstrates that the existing legislation adopted at different levels addresses most of the criteria of social acceptability through binding rules and supporting guidelines. Nonetheless, some elements of social concerns, such as the impact of escapes or the degradation of the landscape, remain unaddressed. Several actions are proposed that should be implemented by all actors involved in aquacultural management to improve social attitudes and, thus, the acceptance by the different segments of society. Integr Environ Assess Manag 2023;19:896-909. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Design of a unidirectional water valve in Tillandsia.

The bromeliad Tillandsia landbeckii thrives in the Atacama desert of Chile using the fog captured by specialized leaf trichomes to satisfy its water needs. However, it is still unclear how the trichome of T. landbeckii and other Tillandsia species is able to absorb fine water droplets during intermittent fog events while also preventing evaporation when the plant is exposed to the desert's hyperarid conditions. Here, we explain how a 5800-fold asymmetry in water conductance arises from a clever juxtaposition of a thick hygroscopic wall and a semipermeable membrane. While absorption is achieved by osmosis of liquid water, evaporation under dry external conditions shifts the liquid-gas interface forcing water to diffuse through the thick trichome wall in the vapor phase. We confirm this mechanism by fabricating artificial composite membranes mimicking the trichome structure. The reliance on intrinsic material properties instead of moving parts makes the trichome a promising basis for the development of microfluidics valves.

Superhydrophobic frictions.

Contrasting with its sluggish behavior on standard solids, water is extremely mobile on superhydrophobic materials, as shown, for instance, by the continuous acceleration of drops on tilted water-repellent leaves. For much longer substrates, however, drops reach a terminal velocity that results from a balance between weight and friction, allowing us to question the nature of this friction. We report that the relationship between force and terminal velocity is nonlinear. This is interpreted by showing that classical sources of friction are minimized, so that the aerodynamical resistance to motion becomes dominant, which eventually explains the matchless mobility of water. Our results are finally extended to viscous liquids, also known to be unusually quick on these materials.