Fig. 6.

Experimental connection and prediction of the dependence of phase sensitivity on irreversibility γ. a By assuming k₁ is increased by 70% and k₄ by 30% during a temperature up perturbation (0.1 period), the PRC from the AI model (black line) can be fitted to that of a temperature up PRC (symbols) observed in⁵⁷. Simulation trajectory of oscillation along with the circadian time scale are shown in the inset. The peak of activator rhythm is defined as CT 0. Experimental PRC data from ref. ⁵⁷ is aligned with the model PRC to peak at the same CT. b PRCs for the same perturbation as in a is computed for different background levels of ATP/ADP ratio or equivalently different values of γ (given in the legend). The extra free-energy dissipation for each γ choice are: ΔW − W_c ≈ 170 (blue); 250 (red); 350 (black, same as in a). Amplitude of PRC increases as sensitivity χ is enhanced by $-\log \gamma$ or ΔW as shown in the inset, where the hollow circles correspond to different choices of (γ₁, γ₂). This prediction can be tested experimentally