Some journals use the term conflicts of interests while the others use competing interests. Those two look similar in concept (even synonym at journals) but I doubt that. I found an answer regarding web contracts and law at http://answers.yahoo.com/question/index?qid=20090817213858AAGQso3 but I'm still looking for a comprehensive clarification of why the journals use different statements and even then I'm not sure if the author understands such terms while they write "none to be declared".