Dead time, activation analysis

A corollary to the mechanisms of cell-death execution is that a dying cell does not need to reach a stable apoptotic state to be dead. This creates a logistical problem for many standard dynamical-systems approaches (nullclines, bifurcation analysis, etc.) that are based on steady-state solutions to the governing equations. Aldridge and coworkers applied finite-time approaches (that do not require d/df = 0) to define the separation of cellular trajectories in a model of caspase activation (Aldridge et al. 2006). These types of approaches may be particularly relevant for other irreversible cell-fate choices, such as during the mitotic-spindle checkpoint. 

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