Warren Buffett intensified his feisty defense of a controversial mortgage transaction marketed by Goldman Sachs Group, saying the investment bank’s behavior does not warrant public fury. Buffett also said he is seeing real signs of improvement in the economy, especially in manufacturing, though it will take another year for a sustainable housing recovery to take hold. The world’s third-richest person spoke at a press conference, a day after his company Berkshire Hathaway held its annual meeting for tens of thousands of shareholders.