Schematic diagrams for circadian oscillator with light adaptation.

<p>Three kinds of light induction were theoretically considered that are up-regulation of transcription by light in the form of light adaptation (A), slow response, and no adaptation (B). In the case of light adaptation, the up-regulated transcription rate remains at a maximal value, <i>X<sup>max</sup></i> for a certain period with duration <i>T<sub>s</sub></i>. Subsequently, the transcription rate decreases over a decay time, <i>T<sub>d</sub></i>, and reaches to the basal transcription rate under dark (A). In the case of slow response, the up-regulated transcription rate increases over a period <i>T<sub>r</sub></i> and reaches to the maximum (B).</p>