the procurement of the services, on a temporary basis, of individual consultants, or organizations thereof, with the prior consent of the Committee on Rules and Administration; such services may be procured by contract with the providers acting as independent contractors, or in the case of individuals, by employment at daily rates of compensation not in excess of the per diem equivalent of the highest gross rate of annual compensation which may be paid to employees of a standing committee of the Senate; and any such contract shall not be subject to the provisions of section 6101 of title 41 or any other provision of law requiring advertising; and

with the prior consent of the Government department or agency concerned and the Committee on Rules and Administration, use on a reimbursable basis (with reimbursement payable at the end of each calendar quarter for services rendered during such quarter) of the services of personnel of any such department or agency.