Table 1.

Summary of model parameters and other quantities

Parameter/Quantity	Meaning
D	diffusion constant
J	production/injection rate per unit area
μ	degradation rate
$\lambda \equiv \sqrt{D/\mu }$	decay length
L	system length
A	area of system perpendicular to x
T	time at which fixed-time scenario is applied
Δx	jump in x over which to calculate ρ′
Δt	jump in t over which to calculate $\dot{\rho }$
Wx	spatial length of averaging window
Wt	temporal length of averaging window
Nx	number of measurements along x in averaging window
Nt	number of measurements along t in averaging window
x∗	threshold position separating regions above and below threshold
t1∗	time when threshold is first exceeded
t2∗	time in $\dot{\rho }$-model when $\dot{\rho }$ drops below threshold
τ ≡ t2∗ − t1∗	total time in $\dot{\rho }$-model for which threshold is exceeded
${\overline{x}}^{\text{∗}},{\sigma }_x$	mean and width of x∗ distribution
${\overline{t}}^{\text{∗}},{\sigma }_t$	mean and width of t∗ distribution
$\overline{\tau },{\sigma }_{\tau }$	mean and width of τ-distribution