  Recent analyses of datasets acquired at the Brookhaven National Laboratory
and at the Physikalisch-Technische Bundesanstalt both show evidence of
pronounced annual variations, suggestive of a solar influence. However, the
phases of decay-rate maxima do not correspond precisely to the phase of minimum
Sun-Earth distance, as might then be expected. We here examine the hypothesis
that decay rates are influenced by an unknown solar radiation, but that the
intensity of the radiation is influenced not only by the variation in Sun-Earth
distance, but also by a possible North-South asymmetry in the solar emission
mechanism. We find that this can lead to phases of decay-rate maxima in the
range 0 to 0.183 or 0.683 to 1 (September 6 to March 8) but that, according to
this hypothesis, phases in the range 0.183 to 0.683 (March 8 to September 6)
are "forbidden." We find that phases of the three datasets here analyzed fall
in the allowed range.
