Campus flags will be at half-mast Thursday to mark the memorial service for Wendy Dempsey, a U of G employee for 38 years, who died April 2. She was an undergraduate preparation room technician in the Department of Chemistry. She is survived by a sister, Nancy; and brothers, Jim and Bob. A tree will be planted in her memory in the Wall-Custance Memorial Forest at the Arboretum in September.  A celebration of her life and free skate will be held at Exhibition Park Arena, 70 Division St., Thursday from 6 to 9 p.m.