Could this be a turning point? A rebel unit comprised of army defectors launched a huge coordinated attack against Syrian troops in Aleppo on Friday. Three offensives targeted an artillery training school, a compound of the air force intelligence and an army checkpoint, according to a local activist. The attacks come two days after President Bashar al Assad admitted that his troops have not been able to squash the rebellion. The battle for Aleppo, Syria’s second-largest city, has lasted more than a month, with neither side able to push the other out.