Before revision:  The denaturation transition is studied , for heterogeneous short sequences of DNA,  in the framework of a mesoscopic Hamiltonian model which accounts for the helicoidal geometry of the molecule.
After revision:  The denaturation transition is studied , for heterogeneous short sequences of DNA, i.e. \sim 100 base pairs, in the framework of a mesoscopic Hamiltonian model which accounts for the helicoidal geometry of the molecule.