Gruppo di Fisica Statistica

We apply the dynamic model for failures to a living organism under periodic stress and study how the health status of the organism evolves. It is found that without healing, the average fraction of intact cells decays either stepwise to zero or to a constant value far from zero, depending on the peak value of the periodic stress. As the parameter measuring the healing probability is raised from zero, the fraction exhibits oscillating behavior, reminiscent of periodic synchronization. The power spectrum at the stress frequency at first increases with the healing parameter, then decreases, which may be called healing resonance. We also study the time evolution of the system in the case that the healing parameter varies periodically with time and observe a transition from the unhealthy state to the healthy one as the healing frequency increases. This suggests how to adjust the frequency of medical treatment to the optimum.