It's a ghastly moment when your computer freezes. But spare a thought for Gavin Renwick, Dundee University's new professor of art and policy, who had to give a public presentation of his work last week after returning from field work in the Arctic. He wrote the text in good time - and then his laptop literally froze, 1,600km from the nearest technical support. His presentation had to be hurriedly rewritten shortly before he got up to speak.