Yahoo plans to breathe some new life into its research and development lab by hiring 50 new PhDs by the end of the year. Spearheaded by CEO Marissa Mayer, the initiative already has resulted in 30 researchers joining the lab, with an additional 20 anticipated by the end of 2013. Yahoo is looking for hires specializing in areas like mobile, Big Data, media science, and pricing and marketplaces. Heading the researchers is Chief Scientist Ron Brachman, a former DARPA director.