Fig. 1. Outflow rates (upper panel) and colloid concentrations (lower panel) as a function of time, where black circles, white squares, and black triangles represent colloid concentrations measured during P₁, P₂, and P₃, respectively. Flow rates are represented by black lines. The gray lines connecting colloid concentrations are provided only to indicate the sequence of colloid concentrations with time. Times of intervention are indicated with vertical, black lines labeled as INT₁ and INT₂.