Claudia Valls Angles, Professor of Instituto Superior Tecnico of
Universidade de Lisboa, Portugal, has done a research stay at MECAMAT
from February 14 to 23. During her stay she has been working with
Professor Montserrat Corbera to the development of a very elegant and
useful method to provide, in a quite simple way, a qualitative study of
the dynamics at infinity of very general classes of polynomial
differential systems including the well-known generalized
Rayleigh—Duffing systems that modelize mechanical oscillators. In
particular these systems posses an infinite number of parameters.