Nature Communications 5: Article number: 3726 (2014); Published: 2 May 2014; Updated: 28 May 2014.

The original version of this Article contained an error in the order in which the first and last name of the author Evangelos Christodoulou were displayed in the author list and as initials in the author contributions statement. This has now been corrected in both the PDF and HTML versions of the Article.