**Acknowledgements**

This work was partially supported by the Foundation of Science and Technology of Portugal through the projects UID/EMS/00285/2013 and ERA-MIN/0002/2015. The work was also supported by projects POCI-01-0145-FEDER-016757 and PTDC/ AAGREC/3839/2014 from the Programa Operacional da Região Centro e Programa Operacional da Região Lisboa, respectively. Rita Branco was funded by grant SFRH/ BPD/110807/2015 and Romeu Francisco by SFRH/BPD/103241/2014. The authors also acknowledge A. Silva and J. Nunes for their contribution in some of the presented results.
