Scientific Reports 2: Article number: 560; published online: 06 August 2012; updated: 06 November 2015

The Acknowledgements section in this Article is incomplete.

“We thank C. Briscoe, J.F. Eichner, L.K. Gallos and H.D. Rozenfeld for useful discussions. This work was supported by National Science Foundation Grants NSF-SES-0624116 and NSF-EF-0827508 and ARL. F.L. acknowledges financial support from The Swedish Bank Tercentenary Foundation. S.H. thanks the European EPIWORK project, the Israel Science Foundation, ONR and DTRA for financial support.”

should read:

“We thank C. Briscoe, J.F. Eichner, L.K. Gallos and H.D. Rozenfeld for useful discussions. This work was supported by National Science Foundation Grants NSF-SES-0624116 and NSF-EF-0827508 and Army Research Laboratory Cooperative Agreement Number W911NF-09-2-0053 (the ARL Network Science CTA). F.L. acknowledges financial support from The Swedish Bank Tercentenary Foundation. S.H. thanks the European EPIWORK project, the Israel Science Foundation, ONR and DTRA for financial support.”