Research Analysts’ upgrades for Wednesday, April 13th: Advanced Energy Industries (NASDAQ:AEIS) was upgraded by analysts at StockNews.com from a hold rating to a buy rating. Alkermes (NASDAQ:ALKS) was upgraded by analysts at StockNews.com from a buy rating to a strong-buy rating. Avinger (NASDAQ:AVGR) was upgraded by analysts at StockNews.com from a sell rating to a […]