Figure 7.

Detection of steps during transport. (A) 2D bead center position histogram in the xy plane in a time window of 2 s. The overlaid dark red trace is from a lowpass-filtered trajectory (100 Hz, Hamming window). (B) Unfiltered bead-position x(t) (green), lowpass-filtered bead-position (gray), and stepped traces evaluated by the step-finding algorithm (black). The mean slope of the trace corresponds to a velocity of 〈v〉 = 60 nm/s. (C) Steppedness, S, as a function of corresponding mean step size 〈s〉. (D) Histogram of ∼800 detected steps with step sizes obtained by the fit, which corresponds to the maximum value of the steppedness in (C). To see this figure in color, go online.