Overview: 2013/09/17 Headlines: 13 Dead, Including Shooter, in Rampage at D.C. Navy Yard; Report: Gun Ownership Linked to Firearm Homicide Rates; U.N. Report Finds "Clear and Convincing Evidence" of Chemical Attack in Syria; Turkey Shoots Down Syrian Helicopter; Typhoon Hits Japan; Death Tolls Rise in Mexico, Colorado Flooding; Report: 50 Top Firms Produce 73 Percent of Emissions; NYC Activists Mark 2nd Anniversary of Occupy Wall Street; Obama Acknowledges Growing Gap Between Rich and Poor; House Bill Would Cut $4 Billion Annually from Food Stamps; Report: NSA Spying on Financial Transactions; NYC: Bill de Blasio Seals Victory in Democratic Primary for Mayor