Figure 5. Combinations of (a) K_max-R, (b) DK-R, and (c) DK-K_max required for "threshold": growth at 10^-10 m/cycle. As suggested by Schmidt and Paris [21], the closure mechanism would cause a transition from K_max-invariant growth to DK-invariant growth at the load ratio at which K_min = K_cl. This transition is most apparent in (c) where the threshold envelope changes from nearly vertical to nearly horizontal. The continued downward slope of the threshold envelope at high K_max values is presumably independent of closure.