Scientific Reports 4, Article number: 6634 (2014); Published: 16 October 2014; Updated: 4 March 2015

This Article contains an error in the Acknowledgements section:

“Data analysis of this work was supported the NSFC projects (D03/41321062 and D0512/0207131138) and the MOST 973 project (2010CB428500).”

should read:

“Data analysis of this work was supported the NSFC projects (D03/41321062 and D0512/41305123) and the MOST 973 project (2010CB428500).”