  We examine published observations of dwarf nova oscillations (DNOs) on the
rise and decline of outbursts and show that their rates of change are in
reasonable agreement with those predicted from the magnetic accretion model. We
find evidence for propellering in the late stages of outburst of several dwarf
novae, as shown by reductions in EUVE fluxes and from rapid increases of the
DNO periods. Reanalysis of DNOs observed in TY PsA, which had particularly
large amplitudes, shows that the apparent loss of coherence during late decline
is better described as a regular switching between two nearby periods. It is
partly this and the rapid deceleration in some systems that make the DNOs
harder to detect.
  We suggest that the 28.95 s periodicity in WZ Sge, which has long been a
puzzle, is caused by heated regions in the disc, just beyond the corotation
radius, which are a consequence of magnetic coupling between the primary and
gas in the accretion disc. This leads to a possible new interpretation of the
`longer period DNOs' (lpDNOs) commonly observed in dwarf novae and nova-like
variables.
