This study was supported by funding FEDER through COMPETE e Programa Operacional Factores de Competitividade and by National funding through FCT-Fundac¸ ão para a Ciência e Tecnologia, within the research project FUBIA FCOMP-01-0124-FEDER-008651 (Ref. PTDC/AAC-CLI/103719/2008) and through a PhD grant ref.