Reacting to what Random House says are "enormous changes" in the library and academic markets brought about by federal funding cutbacks and municipal budget constraints, the publisher has combined its library and academic marketing departments into a single unit. The new department will be headed by Marcia Purcell, who has been appointed v-p, director, library and academic marketing. Purcell, formerly director of library marketing, will report to Skip Dye, a Random sales group v-p, who said the new unit will give Random a better opportunity to cross-market to its institutional accounts. No jobs have been eliminated, although Martha Kemplim, who resigned as director of academic marketing in August, has not been replaced.