In two separate incidents, as many as 15 teens have stormed Chicago Transit Authority buses, attacked their victims and darted off with cell phones and other electronic devices, authorities said Tuesday. Both incidents were near the University of Illinois at Chicago campus, prompting city and campus authorities to issue community alerts. In the first attack, near West Roosevelt Road and South Loomis Street at about 11:40 p.m. Saturday, a victim was struck multiple times before the thieves ran off with his cell phone. About 25 minutes later, near South Racine Avenue and West 13th Street, a student said he was...