Hi all, I've updated the last version of the talk and I've linked it to the web page of today's meeting. You can find the pdf and the ppt. there is still time for comments, questions, hints, and they're really welcomed. thanks much to all, alessio ______________________________________________________ Alessio Sarti Universita' & I.N.F.N. Ferrara tel +39-0532-781928 Ferrara roma +39-06-49914338 SLAC +001-650-926-2972 "Vorrei tanto sapere chi e' che va in giro a costruire quadrati sull'ipotenusa"