Fatemeh Salimi Namin*, Victorien Barbet**
Edward Levavasseur : edward.levavasseur[at]univ-amu.fr
Océane Piétri : oceane.pietri[at]univ-amu.fr
Morgan Raux : morgan.raux[at]univ-amu.fr
*This paper investigates the presence of monthly seasonal anomalies in the dollar-euro foreign exchange market. Using a non-linear Markov-switching framework, we provide some new evidence on the presence of the January effect for that currency pair over the full floating exchange rate period, 1971 to 2017, as a violation of the efficient market hypothesis in the foreign exchange market. The January effect in the dollar-euro is not an old phenomenon but is still very much present.
**We present a model showing the evolution of the organization of agents who discuss democratically about good practices. This model is based on a field study we led for some years following NPOs called "AMAP" in France and their structuration along the time at regional and national level. Most of the hypothesis we make are either based on the literature on opinion diffusion or our field study results. Defining a dynamics where agents influence each other, make collective decision at the group level, and decide to stay or leave their group, we analyse the effect of different forms of informative communication to spread the good practice. Our main indicators for the good functioning of the democratic dynamics are stability and representativeness. We show that communication on norms has a positive impact on both stability and representativeness, if well designed. Interestingly the effect of communication increases with the number of dimensions discussed in the groups. Communication about norms is then a valuable tool to implement in groups that wish to improve their democratic practices without having a large drawback on their stability.