  Several simple growth and decay models use concepts and measures from fractal
geometry. Kinetic models relevant to condensed matter observations arerecalled.
They should be specifically adapted with appropriate degrees of freedom in
order to reproduce power law behaviors, e.g. of species extinctions, cloud
fracture, financial crashes. This allows one to illustrate scientific problems
relevant to the growth and control of epidemias, and other event or entity
propagation in biology, ecology, traffic and economy.
