Stochastic shielding and the power spectrum when all transition rates equal unity.

<p><b>Panel A</b> shows that the majority of the power comes from the observable edges (red dashed line), as expected from the edge importance measure and the stochastic shielding method. Black line is the total power spectral density (<i>S</i>) for the observed process <i>X</i>, red dashed line is the PSD (<i>S</i>_3,4) for the approximate process <i>X</i>_3,4 with noise from observable edges preserved, blue dashed line is PSD (<i>S</i>_1,2) for the approximation <i>X</i>_1,2 with noise from hidden edges preserved. <b>Panel B</b> shows trajectories (Gaussian version of the model) of the full observed process with all noise sources included (black trace), the approximate process with noise preserved on the observable edges (red), and the approximate process with noise preserved on the hidden edges (blue). The red trace closely follows the black trace, whereas the blue trace only tracks mean behavior and misses most fluctuations; <i>X</i>_3,4 is the best approximation of <i>X</i>, in agreement with the stochastic shielding method.