Universal construction of quantum dynamical R matrices and a variant of the Hubbard model with pair hopping

A construction of universal dynamical R-matrices is presented. It is based on a solution F of a shifted cocycle relation. F provides a twist from the usual universal R-matrix to a dynamical one, solution of the Gervais-Neveu-Felder equation. In the second part, we construct two quantum spin chain Hamiltonians with quantum sl(2|1) invariance. These spin chains define variants of the Hubbard model and describe electron models with pair hoppings.