Transition from traveling to standing waves as a function of frequency in a reaction-diffusion system

The addition of polyethylene glycol to the Belousov-Zhabotinsky reaction increases the frequency of oscillations, which in an extended system causes a transition from traveling to standing waves. A further increase in frequency causes another transition to bulk oscillations. The standing waves are composed of two domains, which oscillate out of phase with a small delay between them, the delay being smaller as the frequency of oscillations is increased.