On quantum gravitational effects in an isotropic Universe

Vacuum polarization effects induced by an external gravitational field in a systeM of spjnor, scalar or vector mass particles are considered on the basis of the model of conformally-plane time-space. Expressions for the radiative corrections are obtained and the role they play in the theory of gravitation in the asymptotic regions of weak (|Rsub(i)sup(k)|<>msup(2)) gravitational fields is analyzed. Formulae for the rate of spontaneous production of real particles by a strong gravitational field are presented in the Appendix as well as formulae for the energy-momentum tensor for real particles in the ultrarelativistic limit. The law of increase of entropy in an ultrarelativistic medium is formulated