determining a first positive transition temporal relationship of {TAIL ~ the first positive transition} to {HEAD ~ a first reference positive transition time}; and 
determining a first positive transition temporal relationship of { TAIL ~ the first positive transition } to { HEAD ~ a first reference positive transition time } ; and
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH