By Martin Baccardax Activists Elliot Management will lead a group of private equity buyers paying $16 billion for the TV ratings group. Nielsen Holdings (NLSN) – Get Nielsen Holdings Plc Report shares soared higher Tuesday after a consortium of buyers lead by activist investors Elliott Investment Management agreed to acquire the TV ratings group for $16 billion. The Wall Street Journal first reported the deal Tuesday, which will see private equity buyers, including Brookfield Asset Management and Elliott affiliate Evergreen Coast Capital Corporation pay $28 a share for Nielsen, a level that, a…