Acknowledgement and funding
This study was supported by grants provided by FIR 2014-2016,
University of Catania, Italy. The authors would like to thank Prof.
Iain Halliday for commenting and making corrections to the paper.
Publication history
Editor: Lingyan Wang, Oregon Health & Science University, Portland.
Received: 18-Nov-2014 Final Revised: 24-Dec-2014
Accepted: 29-Dec-2014 Published: 03-Jan-2015