New tools for the study of attractors

International audience; In many biological systems, the localisation of attractors of the dynamics and the quantification of the degree of synchrony is very difficult to obtain from experimental data. We propose here new notions of confiners and entropy to solve this problem and we give some examples of application (an "academic example" concerning the noised van der Pol oscillator and two realistic possible fields of application, namely respiratory physiology and population dynamics).