An epidemic of mass shootings, including the brutal killings of 20 children and six adults from Sandy Hook Elementary School in Newtown, Connecticut, has shaken the nation. But some urban communities live with the relentless reality of gun violence every day. Here in Northern California, in places like Oakland, San Jose, Richmond, Vallejo and Fresno, a recent violent crime surge has made residents anxious. We devote our full program this week to the topic of gun violence in our communities.