Scientific Reports 6: Article number: 20697; published online: 08 February 2016; updated: 20 April 2016.

The original version of this Article contained errors in the spelling of the authors Elena Sánchez-Cuartielles and Rafael Valdés-Mas which were incorrectly given as Sánchez-Cuartielles Elena and Valdés-Mas Rafael respectively. These errors have now been corrected in the PDF and HTML versions of the Article.