 To characterize the distribution of the burst durations, we determine the distribution of exit points located on the two-dimensional separatrix \Sigma .
<meaning-changed>  To characterize the distribution of the burst durations, we determine the distribution of exit points located on the two-dimensional separatrix \Sigma .
 We show that the variability in the burst durations, we determine the distribution of exit points located on the two-dimensional separatrix \Sigma .