Not for articles, though. The only way to exert a negative influence on an article is to become an editor, which apparently requires meeting pg personally and participating in a secret ritual, after which your identity can never be revealed.

You can't use down-votes on articles, only on comments, and not on comments which are replies to your own articles (presumably to kill off the "OH-EM-GEE, that guy disagrees with me, I need to down-vote him in to oblivion!" mindset.)