Jose Sergio Gabrielli steps down and names Maria das Gracas Foster the first woman to head one of the world's largest oil companies, Petrobras.Petrobras CEO Jose Sergio Gabrielli yesterday announced a decision to resign and hand his title over to the first woman to run one of the world's top five oil companies, Maria das Gracas Foster. She will takeover the industry's largest investment plan of a $225 billion proposal to more than double the company's output by the end of the decade, while Gabrielli pursues a career in politics.Petrobras developed the world's first system for deepwater subsea separation of heavy oil and water. Foster will now...