A California man who pleaded guilty in Iowa to child sexual exploitation has been given 30 years in a federal prison.Prosecutors say 22-year-old David Vogelpohl, of Vista, California, was sentenced Tuesday in U.S. District Court in Cedar Rapids. He must serve five years of supervised release after he leaves prison and must comply with sex offender requirements.He had admitted that he persuaded a girl under 18 to engage in sexually explicit conduct last year for the purpose of producing visual depictions.