An elementary proof of the conley — Zehnder theorem in symplectic geometry.- An "A-Priori" estimate for oscillatory-equations.- On the structure of germs of vector fields in ?3 whose linear part generates rotations.- Fixed point results for symplectic maps related to the arnold - conjecture.- Topological invariants as numbers of translation.- Abelian integrals and global hopf bifurcations.- On the numerical determination of the dimension of an attractor.- Global stability of generic two-parameter families of gradients on three-manifolds.