Magneto-dilatonic Bianchi-I cosmology: isotropization and singularity   problems
  We study the evolution of Bianchi-I space-times filled with a global unidirectional electromagnetic field $F_{mn}$ interacting with a massless scalar dilatonic field according to the law \Psi(\phi) F^{mn} F_{mn} where \Psi(\phi) > 0 is an arbitrary function. A qualitative study, among other results, shows that (i) the volume factor always evolves monotonically, (ii) there exist models becoming isotropic at late times and (iii) the expansion generically starts from a singularity but there can be special models starting from a Killing horizon preceded by a static stage. All these features are confirmed for exact solutions found for the usually considered case \Psi = e^{2\lambda\phi}, \lambda = const. In particular, isotropizing models are found for |\lambda| > 1/\sqrt{3}. In the special case |\lambda| = 1, which corresponds to models of string origin, the string metric behaviour is studied and shown to be qualitatively similar to that of the Einstein frame metric. 
K.A. Bronnikov, E.N. Chudaeva and G.N. Shikin (Moscow)