Filming on the road, which injects an element of uncertainty, is another method Salles uses to foster natural improvisation.

CNN: Walter Salles: Back on the road

Aris Candris, chief executive of Westinghouse, said the nuclear accident in Japan added an element of uncertainty to the NRC's review.

WSJ: NRC Approves Toshiba Reactor Design

There is an element of uncertainty to his play sometimes.

BBC: World Cup scouting: left-backs