Summary

Licensing

This file is licensed under the Creative Commons Attribution 2.0 Generic license.

You are free:

• to share – to copy, distribute and transmit the work
• to remix – to adapt the work

Under the following conditions:

• attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

https://creativecommons.org/licenses/by/2.0CC BY 2.0 Creative Commons Attribution 2.0 truetrue

This file, which was originally posted to https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4060055/figure/F1/, was reviewed on 9 December 2018 by reviewer Leoboudv, who confirmed that it was available there under the stated license on that date.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.