Modelado de sistemas complejos mediante simulación basada en agentes y mediante dinámica de sistemas

A consistent access to food is paramount for humans at individual and group level. Besides providing the basic nutritional needs, access to food defines social structures and has stimulated innovation in food procurement, processing and storage. We focus on the social aspects of food storage, namely the role of cooperation for the emergence and maintenance of common stocks. Cooperative food stocks are examined here as a type of common-pool resource, where appropriators must cooperate to avoid shortage (i.e. the tragedy of commons). 'Food for all' is an agent-based model in which agents face the social dilemma of whether or not to store in a cooperative stock, adapting their strategies through a simple reinforcement learning mechanism. The model provides insights on the evolution of cooperation in terms of storage efficiency and considering the presence of social norms that regulate reciprocity. For cooperative food storage to emerge and be maintained, a significant dependency on the stored food and some degree of external pressure are needed. In fact, cooperative food storage emerges as the best performing strategy when facing environmental stress. Likewise, an intermediate control over reciprocity favours cooperation for food storage, suggesting that concepts of closed reciprocity are precursors to cooperative stocks, while excess control over reciprocity is detrimental for such institution.Research for this article was funded in parts by the SimulPast Consolider (CSD2010-00034). A.A. contribution was partially funded by the Spanish Ministry of Economy and Competitiveness (MINECO FPI BES-2013-062691), and it is part of the activities of the Equip de Recerca Arqueòlogica i Arqueomètrica, Universitat de Barcelona (ERAAUB), as a research group consolidated by the Generalitat of Catalonia (2014 SGR-845). A.L.B. has contributed to this paper as part of activities of the Complexity and Socio-Ecological Dynamics Emergent Research Group consolidated by the Generalitat of Catalonia (2014 SGR-1417), on contracts from the Juan de la Cierva Programme (MINECO JCI-2011-10734) and during a visiting fellowship at the Cluster of Excellence CliSAP (DFG EXC177).Peer Reviewe

This is part two of a three‐part series discussing parasites of the heart. In this section, we present an overview on parasitic diseases predominantly involving the myocardium. Copyright

We study the influence that resource availability has on cooperation in the context of hunter-gatherer societies. This paper proposes a model based on archaeological and ethnographic research on resource stress episodes, which exposes three different cooperative regimes according to the relationship between resource availability in the environment and population size. The most interesting regime represents moderate survival stress in which individuals coordinate in an evolutionary way to increase the probabilities of survival and reduce the risk of failing to meet the minimum needs for survival. Populations self-organise in an indirect reciprocity system in which the norm that emerges is to share the part of the resource that is not strictly necessary for survival, thereby collectively lowering the chances of starving. Our findings shed further light on the emergence and evolution of cooperation in hunter-gatherer societies.