It's hard to imagine how a doctor could miss Jimi Hammerstein's primary health risk. The graying Brooklyn native spent most of the last 10 years upstate for slinging dope in Park Slope—back when the neighborhood was still in transition. "I remember when this neighborhood wasn't nothing like this," he says, laughing as he sits in a drop-in center for ex-offenders on Fourth Avenue, the Slope's still-gritty border with Downtown Brooklyn. "This was... More >>>