Figure 2: Feedback-regulated molecular fluctuations.
From: Delay-induced anomalous fluctuations in intracellular regulation
(a) The size of the stoichiometric delay coefficient sd for different feedback gains and feedback delays in the SFM with n=100. Macroscopic oscillations of the concentration appear with parameters in the white area. (b,c) Intrinsic noise measured by the Fano factor of the SFM and the DFM. In (b), the solid line is the LNA, the plus signs stochastic simulations of the SFM and the circles stochastic simulations with delays for the DFM, with feedback delays sampled from 
. The orange symbols are the results for n=10, the brown symbols for n=100 and the red symbols for n=1,000. The black circles are simulations for the DFM with a fixed feedback delay, equivalent to the 'n=∞' limit. In (c), simulations of the DFM with fixed delay, corresponding to n=∞. Orange circles are simulations of the DFM with a feedback gain φ=0.2, brown circles φ=0.4 and red circles φ=0.6. The dashed lines are approximations of the value of the Fano factor at the plateau calculated from equation (14). In both (b) and (c), the errors are smaller than the symbols.
