Fig 4. Recurrence time and position in the plume.

(A) Example trajectory in reconstructed phase space. Two types of recurrence time index are obtained by averaging time intervals between all successive recurrent points (${\overline{T}}_1$) or only returning points (${\overline{T}}_2$) in a circle of radius r centered at a reference point x ₀. To estimate ${\overline{T}}_1$, the refractory period of at least some bORNs in the population would need to be short relative to the times between successive recurrence points. ${\overline{T}}_2$ can be estimated with longer refractory periods. (B) Mean (points) and standard deviation of ${\overline{T}}_1$ and ${\overline{T}}_2$ indices for positions in downstream direction. (C) Mean and standard deviation of ${\overline{T}}_1$ and ${\overline{T}}_2$ indices for positions in cross-stream direction.