Convert a list of rational durations to a list of QEvent objects.
Negative duration values can be used to indicate silence. Any resulting pitched QEvent objects will default to using middle-C.
abjad> from abjad.tools.quantizationtools import tempo_scaled_rationals_to_q_events
abjad> durations = [Duration(-1, 2), Duration(1, 4), Duration(1, 6)]
abjad> tempo = contexttools.TempoMark((1, 4), 55)
abjad> tempo_scaled_rationals_to_q_events(durations, tempo)
[QEvent(Offset(0, 1), None), QEvent(Offset(24000, 11), 0), QEvent(Offset(36000, 11), 0), QEvent(Duration(4000, 1), None)]
Return a list of QEvent objects.