Alejandro Gangui is a postdoctoral research associate in the Département d'Astrophysique Relativiste et de Cosmologie at the Observatoire de Paris-Meudon in France. He received his Ph.D. in astrophysics from the International School for Advanced Studies in Trieste, Italy, under the supervision of Dennis Sciama. His research interests include the observable consequences of cosmic topological defects and the cosmic microwave background radiation. Address: DARC, Observatoire de Paris-Meudon, 92195 Meudon, France. Internet: gangui@obspm.fr