Local and global interactions in an evolutionary resource game

Conditions for the emergence of cooperation in a spatial common-pool resource game are studied. This combines in a unique way local and global interactions. A fixed number of harvesters are located on a spatial grid. Harvesters choose among three strategies: defection, cooperation, and enforcement. Individual payoffs are affected by both global factors, namely, aggregate harvest and resource stock level, and local factors, such as the imposition of sanctions on neighbors by enforcers. The evolution of strategies in the population is driven by social learning through imitation, based on local interaction or locally available information. Numerous types of equilibria exist in these settings. An important new finding is that clusters of cooperators and enforcers can survive among large groups of defectors. We discuss how the results contrast with the non-spatial, but otherwise similar, game of Sethi and Somanathan (American Economic Review 86(4):766–789, 1996)

PLANET TOPERS: Planets, Tracing the Transfer, Origin, Preservation, and Evolution of their ReservoirS

The Interuniversity Attraction Pole (IAP) ‘PLANET TOPERS’ (Planets: Tracing the Transfer, Origin, Preservation, and Evolution of their Reservoirs) addresses the fundamental understanding of the thermal and compositional evolution of the different reservoirs of planetary bodies (core, mantle, crust, atmosphere, hydrosphere, cryosphere, and space) considering interactions and feedback mechanisms. Here we present the first results after 2 years of project work. © 2016, Springer Science+Business Media Dordrecht

LaRa, an X-band coherent transponder ready to fly

LaRa is a radio-science instrument that is ready to fly and was part of the science payload of the surface platform of the ExoMars mission. Now that ExoMars is suspended, LaRa will need to find another mission to go to the Martian system (or elsewhere in the inner Solar System). The LaRa instrument consists of an X-band transponder accompanied by a set of three antennas and three RF cables. This instrument is designed to measure with a couple of mHz of accuracy the Doppler shift induced by the variations in Mars rotation and orientation on a direct-to-Earth round-trip radio link. The main scientific objective of the LaRa experiment is to constrain the interior structure of Mars by precisely measuring the precession and nutations of the planet’s spin axis. LaRa’s measurements can also be used to refine the rotation model of Mars, including the polar motion, and infer constraints on the dynamic of its atmosphere

Village politics: Heterogeneity, leadership and collective action

When comparing stratified Fulani village societies, little direct relationship between the degree of heterogeneity and the success in collective action was found, except when heterogeneity among leadership and elite groups was compared. Small size and homogeneous groups do not seem to be general preconditions for stronger ability to perform collectively. First, it was found that homogeneity among elite groups enhanced capacity for collective action. Second, it was when heterogeneity in economic interests between elite groups intensified and coincided with other dimensions of heterogeneity that collective action became difficult to achieve, such as heterogeneity in economic wealth, access to land and common-pool resources, and agreement over authority of the leadership. Third, collective action was enhanced by political elites and leaders being a bit better endowed and a bit wealthier than the average community members, but not when their assets were mobilised against the economic interests and sense of fairness of other social groups. Fourth, the coordination power of the leadership related to the management of common-pool resources was undermined when leadership had extensive recourse to state officials external to the village community, underscoring the importance of autonomy.