Project title
This work was supported by the Fundo Europeu de Desenvolvimento Regional-QREN-Compete through projects SFRH/BD/61637/2009, PTDC/AAC-CLI/098308/ 2008, PTDC/AAC-CLI/118092/2010, PTDC/FIS/102284/2008 and PEst-C/FIS/UI0036/2011 – Fundac¸a˜o para a Cieˆ ncia e Tecnologia (FCT).