After paralyzing operations at the offshore platforms and refineries of Brazil’s troubled National Oil Company Petrobras for the last three days, workers ended a strike Monday.  Members of the Federation of Petroleum Workers walked off the job just before Christmas after rejecting a proposed salary increase that fell short of inflation.  The union is also concerned about a contract changes that could reduce hours for the company’s 85,000 workers.  The strike occurred against the backdrop of a massive corruption scandal in the company, involving price-fixing and kickbacks.