A woman gestures as federal riot police clash with supporters of former presidential candidate Andres Manuel Lopez Obrador of the PRD (Party of the Democratic Revolution), and demonstrators try to block access to the alternative senate building in Mexico City October 23, 2008. Mexico's Senate began passing an energy reform on Thursday to reshape the slumping state-run oil industry and bring in private sector expertise. The reform, also backed by much of the opposition, is expected to clear the Senate on Thursday and win approval in the lower house Chamber of Deputies as early as next week. [Agencies]