Daily records of international crude oil prices are studied by means of a Zipf-type analysis. By using simple up-down information on price fluctuations, we have observed phase transitions between symmetric states, where occurrence of up and down fluctuations are almost equal, to anti-symmetric...

We present the results of a first exploratory survey of chaotic hamiltonian pumps, constructed as ratchets of finite extension. Two simple models are studied, composed of single or double square potential wells subject to a two-parameter driving that acts on the depth or the position of the...

A chemical excitable medium was constructed where the velocities of wave propagation to the left and to the right are different. It consists of a network of the “chemical diode” elements, with a gap 150mm between the “presynaptic” and “postsynaptic” parts. With this gap, a chemical...