  We report an investigation of cosmological parameters based on the
measurements of anisotropy in the cosmic microwave background radiation (CMB)
made by ACBAR. We use the ACBAR data in concert with other recent CMB
measurements to derive Bayesian estimates of parameters in inflation-motivated
adiabatic cold dark matter models. We apply a series of additional cosmological
constraints on the shape and amplitude of the density power spectrum, the
Hubble parameter and from supernovae to further refine our parameter estimates.
Previous estimates of parameters are confirmed, with sensitive measurements of
the power spectrum now ranging from \ell \sim 3 to 2800. Comparing individual
best model fits, we find that the addition of \Omega_\Lambda as a parameter
dramatically improves the fits. We also use the high-\ell data of ACBAR, along
with similar data from CBI and BIMA, to investigate potential secondary
anisotropies from the Sunyaev-Zeldovich effect. We show that the results from
the three experiments are consistent under this interpretation, and use the
data, combined and individually, to estimate \sigma_8 from the
Sunyaev-Zeldovich component.
