tokens: The authors extend their thanks to the referee for important comments and suggestions. This research has been partly co-financed by the European Union (European Social Fund -ESF) and Greek national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: “Thales. Investing in knowledge society through the European Social Fund”. S.P. acknowledges support from an FP7 Marie Curie Grant (FP7-PEOPLE-2010-RG/268288). M.K.G. wishes to acknowledge support from the EU’s Seventh Framework Programme under grant agreement no PIRG07-GA-2010-268245. The authors acknowledge the Variability of the Sun and Its Terrestrial Impact (VarSITI) international program.
ner_tags: O O O O O O O O O O O O O O O O O O O O O B-Location I-Location B-Organization I-Organization I-Organization B-Organization O B-Location O O O O B-Grant I-Grant I-Grant I-Grant I-Grant I-Grant O O B-Grant I-Grant I-Grant I-Grant B-Grant O B-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant I-Grant B-Person O O O O B-Grant I-Grant I-Grant I-Grant B-Grant B-Person O O O O O O B-Location B-Grant I-Grant I-Grant O B-Grant I-Grant I-Grant I-Grant O O O O B-Survey I-Survey I-Survey I-Survey I-Survey I-Survey I-Survey I-Survey B-Survey O O