On page 5995 of the 1 December 2011 issue, there is an error in the Authorship section. In the Contribution paragraph, in addition to appearing correctly with the group of authors that performed the research and helped in collecting data, the initials of Silvia Buttignol (S.B.) were included in error with those of Michele Cavo (M.C.), who designed the research study, performed the research, analyzed the data, and critically revised the manuscript. The Contribution should have read:

Contribution: E.Z. designed the research study, performed the research, analyzed the data, and wrote the manuscript; F.P. and C.N. performed the research and contributed analytical tools; B.Z. performed the research and gave a substantial contribution in analyzing the data; E.E. helped in collecting data; A.P. performed statistical analysis and contributed to data interpretation; P.T., S.B., G.P., A.B., L.P., C.T., and F.C. performed the research and helped in collecting data; M.B., R.F., and S.F. contributed to data interpretation and approved the manuscript; M.C. designed the research study, performed the research, analyzed the data, and critically revised the manuscript. All authors approved the final version of the manuscript and the submission.