Scientific Reports 3, Article number: 1188 (2013); Published: 1 February 2013; Updated: 15 August 2013

Mohan S Maddur was omitted from the author list in the original version of this Article. This has been corrected in the PDF and HTML versions of the Article.

The Author Contributions section should read "J.B. designed research, M.S., P.H. & M.S.M. performed research, all authors analysed the data, V.A., R.B., H.S., P.P. & J.-P.L. provided new research tools. J.B. wrote the paper and all authors reviewed and approved the manuscript."