Philadelphia is one of the deadliest cities in America. Last year, the city had 353 homicides, the most in more than a decade. So far this year, there have been 325 — up 6% from this time last year. Recent events are amplifying calls for action. In the last month alone, 12 children here have been shot, ranging in age from 10 months to 16 years. The most recent was a 16-year-old girl shot in the left shoulder late Saturday afternoon as she got off a SEPTA bus in North Philadelphia.