Scientific Reports 5: Article number: 846210.1038/srep08462; published online February162015; updated June302015
The Acknowledgements section in this Article is incomplete.
“This work has been supported by the European Union under FP7 in the DENFREE project and Fundação para Ciência e Tecnologia (FCT), Portugal.”
should read:
This work has been supported by the European Union under FP7 in the DENFREE project (grant 282378) and Fundação para Ciêcia e Tecnologia (FCT), Portugal, project PEst-OE/MAT/UI0209/2013