By Sophie Sassard and Aditi Shrivastava LONDON, Feb 14 (Reuters) - British fund manager Aberdeen Asset Management has unveiled two acquisitions, a U.S. fund manager and a 50.1 percent stake in an international private equity business, to buy its way into new markets. Aberdeen is to buy New York-based asset management firm Artio Global Investors for about $175 million, or $2.75 per share, and the stake in SVG Advisers (SVGA) for 17.5 million pounds ($27 million).