HALCYON HAS STAKE IN RESEARCH-COTTRELL <RC> Halcyon Investments, a New York firm, reported a 6.9 pct stake in Research-Cottrell Inc. Alan Slifka, a partner in Halcyon, told Reuters the shares were purchased for investment purposes but declined further comment. On June 8, Research-Cottrell said it had entered into a definitive agreement to be acquired by R-C Acquisitions Inc for 43 dlrs per share. Research-Cottrell closed at 44-1/4 today, unchanged from the previous close.