News Corp CFO Susan Panuccio to step down, effective Jan. 1, to be succeeded by Lavanya Chandrashekar, ex-Diageo; Panuccio to continue in an advisory capacity for six months ... Cybersecurity company Dot Ai appoints Toni Buhrke, ex-Mimecast, as vice president-global sales, engineering, and operations ... Nvidia names Ellen Ochoa, ex-NASA, to board.