Fig. 1
From: Insight into human pubertal growth by applying the QEPS growth model
The QEPS-model. Left panel: The total height (QEPS) is the sum of four growth functions: a quadratic growth function (Q), a negative exponential growth function (E), a pubertal growth function (P) and a stop function (S) modelling the end of growth for function Q. B = birth, t0 = about 6 weeks after conception. Birth is marked with a vertical line. Age scale below 3 years is stretched out. Right panel: QEPS model for total height, T(age), = E(age) + QS(age) + P(age), with QS(age) = Q(age) – S(age). T max  = E max  + QS max  + P max . AgeP5 and AgeP50 mark the ages where 5% and 50% of P max are reached, AgeS 0 marks the age where the S-function is starting. Originally published in Journal of theoretical biology 2016;406:143–65, Nierop AF et al., used by permission of Elsevier journals