Fig. 1

Left panel: five evaluations of the model f _t (x) for different values of x between x=0.1 and 0.5, coloured red to purple respectively, with time t on the x-axis. The measurement of the real system at t=3.5 is denoted z, and is represented as the black point, with ± 3σ _e error bars representing observational error. Right panel: the model at t=3.5. The curved dashed line gives f _t=3.5(x) but now it is represented purely as a function of the input parameter x on the x-axis, with the red to purple points consistent with those in the left panel. The observed data z is given by the solid black horizontal line, with the ± 3σ _e error bars as the horizontal black dashed lines. We see that there will be acceptable values of x approximately between 0.3 and 0.35