Figure 3.

A further digestion of PER protein shifts the phase of the molecular clock. (a) Time curves where the superscript u indicates that these time curves stem from the extended model consisting of (1) to (5) where (2) is replaced by (8) for (16) and $\alpha =1$. (b) Time curve of the external stimulus u defined in (16), of M and $P_0$ calculated from the model (1) to (5) and of $M^u$ and $P_0^u$ calculated from (1) to (5) where (2) is replaced by (8) for (16) and $\alpha =1$. Units and dimensions: abscissa t: time in hours, ordinate U: amount of substance (M, $M^u$ mRNA, $P_i^u$, $\left\{0,,,1,,,2,,,N\right\}$, protein, u intensity of illumination).