In a generational changing of the guard, Arthur Gregg Sulzberger, 37, will become the publisher of The New York Times on Jan. 1. His father, Arthur Ochs Sulzberger Jr., announced on Thursday that he was turning over the post to his son. The ascension of the younger Mr. Sulzberger, who is known as A. G., comes just over a year after he was named deputy publisher of The Times. The New York Times Company’s board voted in favor of the move during a meeting on Thursday. The elder Mr. Sulzberger, 66, who will stay on as chairman of The New...