gvlx is the global handle for Gerardo Lisboa.
Its origin is tracked to the contraction of his name and the Roman abbreviation for the city of Lisboa and was first used at INESC's systems in the beggining on 90's when he was doing some undergraduate studies at Instituto Superior Técnico.
As a professional, you may contact him on his LinkedIn page at: http://pt.linkedin.com/in/gerardolisboa
His twitter account is, obviously, @gvlx.