LAS VEGAS (AP) -- An international study says Las Vegas has one of the worst economies in the world, and prospects for a rapid recovery appear dim.The Brookings Institution and London School of Economics study ranked Las Vegas fifth from the bottom in a ranking of 150 metropolitan areas, citing a limited economy that relies heavily on tourism and construction.Las Vegas fared better than only Dublin; Dubai, United Arab Emirates; Barcelona, Spain; and Thessaloniki, Greece.