Fig. 2.

A DDE model of biofilm oscillations. (A) Scheme of the model. Growth in the periphery leads to metabolic stress in the interior, which is transmitted to the periphery and inhibits growth. Therefore, stress in the periphery ($x$) is considered to exert a negative feedback on itself with some delay ($\tau$). (B) Stress production function $f\left(x\right)$ for $C=1,\alpha =10,\beta =\gamma =1$. The dashed gray line marks $f\left(x\right)=C$. The dotted black line is the Hill function $1+\frac{10}{1+x^2}$. The dashed black line is the Mackey–Glass-like function $1-\frac{20x}{1+x^2}$.