Complex sentence: Hoshino's debut manga appeared in "Weekly Shōnen Jump" in July 2003 and was followed by a one-shot title, "Zone", which was published in "Akamaru Jump" in December 2003.
Split into simpler sentences: Hoshino's debut manga appeared in "Weekly Shōnen Jump" in July 2003. Her one-shot "Zone", which was published in Akamaru Jump in December 2003.