SYDNEY (Reuters) - A fragile calm gripped Asian shares on Tuesday as investors waited anxiously to see if Beijing could stem the rout in Chinese assets, while oil hit 13-month lows as the coronavirus throttled demand in the world's biggest importer of fuel.Brent crude futures crashed to $54.11 a barrel, bringing losses for the year so far to 18%, while U.S. crude sank to $49.99. China's central bank has flooded the economy with cash while trimming some key lending rates, but analysts suspect..