Age distributions of rings by sample. Age distribution of ring stages by sample. For each sample, the x-axis is the age of rings as follows: 1 = 0–6 hours, 2 = 6–16 hours, 3 = 16–26 hours; the y-axis shows the number of rings. Samples 1–5 and sample 10 show high synchronization. Samples 1–5 contained no detectable haemozoin objects.