bhartzer - 9:18 pm on Jul 9, 2013 (gmt 0)
If you look at Google's recent "How Search Works" interactive infographic [google.com...] you'll notice something interesting.
In Part One Crawling and Indexing, they say that "we sort the pages by their content and other factors...". Notice that you see "string theory" separated from "physics" and "P-BRANE".
If Google categorizes things first and then they apply the algo factors, then it could possibly be a way that that they would rank industries differently. They're different topics (different industries), so the factors like linking would only be applied amongst an industry or topic.