The Creutzfeld-Jakob Disease in the Hierarchy of Chaotic Attractors

Until recently model construction was the main tool for understanding the long time dynamical behavior of complex systems [1]. If the experimental measurement of a property of the system exhibited some regularity of behavior, such as for example periodic oscillations, this behavior was often formulated in terms of a set of coupled nonlinear differential equations. The solutions to these equations were compared with the experimental data. However, most often models fit the data only qualitatively and do not account for the variabilities seen in the actual measured time-dependent variables. Today we realize that these variabilities cannot be ignored as they may indicate the presence of dynamics radically different from the assumed models.