Copyright 2014 The Authors. Published under the terms of the CC BY NC ND 4.0 license.  License: This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Except where otherwise noted, this item's license is described as Copyright 2014 The Authors. Published under the terms of the CC BY NC ND 4.0 license. License: This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.