Juri Tukalov. You can see from the exhausted look, just how crushing was the defeat of Russia's Olympic champion, Juri Tukalov, 23, in the first heat of the Diamond Sculls at Henley. (And after he'd eaten a special steak breakfast, too.) The lead was taken at once by Peter Vlasic, of Yugoslavia. Peter was a length up at Fawley and that was where Juri must have decided that, steak or no steak, he couldn't catch his opponent. For he dropped his rate of Striking. And Vlasic sculled away to an easy