  We place constraints on the number of relativistic degrees of freedom and on
the baryon asymmetry at the epoch of Big Bang Nucleosynthesis (BBN) and at
recombination, using cosmic background radiation (CBR) data from the Wilkinson
Microwave Anisotropy Probe (WMAP), complemented by the Hubble Space Telescope
(HST) Key Project measurement of the Hubble constant, along with the latest
compilation of deuterium abundances and measurements of the primordial helium
abundance. The agreement between the derived values of these key cosmological
and particle physics parameters at these widely separated (in time or redshift)
epochs is remarkable. From the combination of CBR and BBN data, we find the
2\sigma ranges for the effective number of neutrinos and for the baryon
asymmetry (baryon to photon number ratio \eta) to be 1.7-3.0 and 5.53-6.76
\times 10^{-10}, respectively.
