  Exact solutions of the dispersive and modified equations are expressed in
terms of special polynomials associated with rational solutions of the fourth
Painleve equation, which arises as generalized scaling reductions of these
equations. Generalized solutions that involve an infinite sequence of arbitrary
constants are also derived which are analogues of generalized rational
solutions for the Korteweg-de Vries, Boussinesq and nonlinear Schrodinger
equations
