GAM modeling of the aEPEC-2 strain. The Figure shows a GAM regression model and the respective derivatives of the growth curves of the aEPEC-2 strain. For the GAM regression model the y-axis designates the scaled OD scores produced with splines with the given degrees of freedom. The x-axis depicts time in minutes. The small black dots on the GAM curves represent the residuals and hence give an impression of the goodness of fit of the GAM models. The figures denoting the respective derivatives of the GAM modeled growth curves show the derivative function of the respective growth curve on the y-axis with corresponding minutes of the x-axis. It can be seen that while growth is generally slow for Syncase broth with lactoferrin added, growth is increasing more abrupt in LB broth before it declines.