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. 2015 Dec 11;5:18018. doi: 10.1038/srep18018

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This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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Only the trends that are significant at p < 0.05 are presented. The figure was generated using ArcGIS 10.0, and the coordinate system is the World Geodetic System 1984 (WGS84).