Harmonic promotes Nimrod Ben-Natan, senior vice president-general manager, broadband business, to president-CEO to succeed retiring Patrick Harshman, effective June 11 ... Backlight, media and entertainment software provider, hires Mosaic Group’s Kathleen Barrett, also former Vimeo, as CEO ... WorldVue, provider of video, digital infrastructure and wireless connectivity services, adds Chris Coles, ex-C&W Networks, as chief business development officer ... Daily newsletter 1440 taps former Time executive Michelle Denhart as vice president-strategy and brand ... C3 AI, enterprise AI application software company, adds outgoing Fortune Media CEO Alan Murray to its board, effective May 1; meanwhile, Fortune announces Chief Strategy Officer-Chief Financial Officer Anastasia Nyrkovskaya as CEO, succeeding Murray, departing at the end of April ... Publishers Clearing House Media names Roey Franco, ex-Firefly, chief product officer ... Captivate, news and entertainment network, rehires its former Senior Vice President-National Sales Leigh Lowery from Outfront Media as chief revenue officer.