We discuss the effect of matter reionization on the large-angular-scale anisotropy and polarization of the cosmic microwave background radiation (CMBR) in the standard CDM model. We separate three cases in which the anisotropy is induced by pure scalar, pure tensor, and mixed metric perturbations respectively. It is found that, if reionization occurs early enough, the polarization can reach a detectable level of sequentially 6%, 9%, and 6.5% of the anisotropy. In general, a higher degree of polarization implies a dominant contribution from the tensor mode or reionization at high redshift. Since early reionization will suppress small-scale CMBR anisotropies and polarizations significantly, measuring the polarization on few degree scales can be a direct probe of the reionization history of the early universe.

We study the implications of a vector-like quark, especially a down-type vector-like quark in b → s(d)γ including the neutral Higgs in the calculation. After analyzing some possible constraints for the mixing, the contribution may be significant for the b → dγ, but not for the b→sγ. We also find that the FCNC among ordinary quarks vanishes for a special form of down-type quark mass matrix.