A research professorship in the name of Helen Gurley Brown, editor of Cosmopolitan magazine, has been established at Northwestern University's Medill School of Journalism. The endowment was established by the Hearst Corp., which publishes Cosmopolitan. It will provide money for both research and teaching in magazine journalism . . .

Mstislav Rostropovich, music director of the National Symphony Orchestra, will journey to Dallas to receive an award Sunday from the Meadows School of the Arts at Southern Methodist University . . .

There may be something rotten in the state of duPont. Alfred duPont Dent, the grandson of Alfred I. duPont, says he believes the millionaire industrialist may have been poisoned in 1935 by his wife and brother-in-law. In an article in the Oct. 28 edition of Forbes magazine, Dent is quoted as saying he believed his grandfather was killed to scuttle a new will that would have reduced Jessie Ball duPont's inheritance and the control her brother, financier Ed Ball, had over the estate . . .

Fans who attended a Dan Fogelberg concert in Denver this week couldn't believe their eyes and ears. What the audience saw was a clean-shaven singer performing with Frankie and the Aliens, a rhythm and blues band, rather than the customarily bearded Fogelberg playing his standard folk music repertoire. Some people -- declaring that Fogelberg had not appeared, as advertised -- demanded their money back, so the concert promoter had the recently debearded singer introduce himself on stage before the second show.