  It is shown that spectral functions within the extended t-J model, evaluated
using the finite-temperature diagonalization of small clusters, exhibit the
high-energy kink in single-particle dispersion consistent with recent
angle-resolved photoemission results on hole-doped cuprates. The kink and
waterfall-like features persist up to large doping and to temperatures beyond
$J$ hence the origin can be generally attributed to strong correlations and
incoherent hole propagation at large binding energies. In contrast, our
analysis predicts that electron-doped cuprates do not exhibit these phenomena
in photoemission.
