Nominations of Michael B. Thornton, Joseph W. Nega, and F. Scott Kieff: hearing before the Committee on Finance, United States Senate, One Hundred Thirteenth Congress, first session, on the nominations of Michael B. Thornton, to be a judge of the United States Tax Court; Joseph W. Nega, to be a judge of the United States Tax Court; and F. Scott Kieff, to be a member of the United States Int