Fig. 8
From: A master stability function approach to cardiac alternans
Zero-contour of the MSF in the (ηc,ηsr) plane for Tp=0.6. Note that both ηc and ηsr are real since we focus on diffusive couling. The MSF is negative in the region labeled S and positive in regions denoted by U. The green curve corresponds to saddle-node bifurcations (+1), while the blue curve refers to period-doubling bifurcations (−1)