DUBAI (Reuters) - A London-based Arab magazine said on Friday that al Qaeda leader Osama bin Laden has vowed to launch a "back-breaking attack" on the United States by February, confirming an earlier message by the militant network. The weekly al-Majalla said it received an e-mail from Abu Mohammed al-Ablaj, a little known al Qaeda member, saying bin Laden would release a video tape in which he affirms his group's determination to fight the United States. "A messenger of bin Laden informed him (Ablaj) that the al Qaeda leader will appear on a televised tape after the execution of an...