Rome prosecutors have opened an investigation after five Italians died while scuba-diving in the Maldives on Thursday, sources said on Friday.     The victims have been named as Monica Montefalcone, her daughter Giorgia Sommacal, Muriel Oddenino, Federico Gualtieri, and Gianluca Benedetti.     The University of Genoa said four of the victims were linked to it.     Montefalcone was an ecology professor with it, Sommacal was one of its biomedical engineering students, Oddenino was a researcher