(Reuters) - UK blue-chip shares fell for a second day on Friday after AstraZeneca and RBS after reported underwhelming results, while investors remained unsettled due to concerns over the impact of the coronavirus on the global economy.The FTSE 100 index was 0.3% lower by 0828 GMT and was set to end the week with a near 1% fall, but the midcap bourse rose 0.3% as it drew strength from the pound. Global markets are expecting stimulus from central banks as the epidemic in China showed no signs..