Murphy's law in action, there was a correction made to the paper you quote, so I clicked through to see what was corrected:

Notice of Republication

This article was republished on March 30, 2015, to correct the sizing and placement of the figures; none of the article content was changed. The publisher apologizes for the original layout errors. Please download this article again to view the corrected version. The originally published, uncorrected article and the republished, corrected article are provided here for reference.