The National Basketball Association and some of its top players take aim at ending gun violence in a television campaign that will launch on Christmas, the league said on Wednesday. In a partnership with Everytown for Gun Safety, the anti-violence group founded and funded by former New York Mayor Michael Bloomberg, the NBA on Friday will begin running a public service announcement during games broadcast on ABC and ESPN that urges a stop to gun violence, the league said. Stephen Curry of the Golden State Warriors, Chris Paul of the Los Angeles Clippers, Carmelo Anthony of the New York Knicks and Joakim Noah of the Chicago Bulls are among the stars whose lives have been touched by gun violence and who appear in the 30-second spot.