  Using high temperature series we calculate temperature derivatives of the
spin-spin and density-density correlation functions to investigate the low
energy spin and charge excitations of the two-dimensional t-J model. We find
that the temperature derivatives indicate different momentum dependences for
the low energy spin and charge excitations. By comparing short distance
density-density correlation functions with those of spinless fermions and hard
core bosons, we find that the t-J model results are intermediate between the
two cases, being closer to those of hard core bosons. The implications of these
results for superconductivity are discussed.
