  We provide the results from a spectral analysis of nuclear decay data
displaying annually varying periodic fluctuations. The analyzed data were
obtained from three distinct data sets: 32Si and 36Cl decays reported by an
experiment performed at the Brookhaven National Laboratory (BNL), 56Mn decay
reported by the Children's Nutrition Research Center (CNRC), but also performed
at BNL, and 226Ra decay reported by an experiment performed at the
Physikalisch-Technische Bundesanstalt (PTB) in Germany. All three data sets
exhibit the same primary frequency mode consisting of an annual period.
Additional spectral comparisons of the data to local ambient temperature,
atmospheric pressure, relative humidity, Earth-Sun distance, and their
reciprocals were performed. No common phases were found between the factors
investigated and those exhibited by the nuclear decay data. This suggests that
either a combination of factors was responsible, or that, if it was a single
factor, its effects on the decay rate experiments are not a direct synchronous
modulation. We conclude that the annual periodicity in these data sets is a
real effect, but that further study involving additional carefully controlled
experiments will be needed to establish its origin.
