  Recent theoretical yields and chemical evolution models demonstrate that
intermediate-mass AGB stars cannot reproduce the observed abundance
distributions of O, Na, Mg, and Al. As a further observational test of this
finding, we present elemental abundance ratios [X/Fe] for 20 elements in 38
bright giants of the globular cluster NGC 6752. Our mean abundance ratios
[X/Fe] are in good agreement with previous studies of this cluster and are also
consistent with other globular clusters and field stars at the same
metallicity. The mean abundance ratios [Ba/Eu] and [La/Eu] exhibit values, in
agreement with field stars at the same metallicity, that lie approximately
midway between the pure r-process and the solar (s-process + r-process) mix,
indicating that AGB stars have played a role in the chemical evolution of the
proto-cluster gas.
  For the first time, we find possible evidence for an abundance variation for
elements heavier than Al in this cluster. We find a correlation between [Si/Fe]
and [Al/Fe] which is consistent with the abundance anomalies being synthesized
via proton captures at high temperatures. Leakage from the Mg-Al chain into
28Si may explain the Si excess in stars with the highest [Al/Fe]. We identify
correlations between [Y/Fe] and [Al/Fe], [Zr/Fe] and [Al/Fe], and [Ba/Fe] and
[Al/Fe] suggesting that Y, Zr, and Ba abundances may increase by about 0.1 dex
as Al increases by about 1.3 dex. While the correlations are statistically
significant, the amplitudes of the variations are small. If the small
variations in Y, Zr, and Ba are indeed real, then the synthesis of the Al
anomalies must have taken place within an unknown class of stars that also ran
the s-process. [Abridged]
