Mindframe (Constitution--Walk of Stars, by Street Sense), most recently winner of the GI Churchill Downs Stakes, will take up stud duties at Claiborne Farm at the conclusion of his racing career, the farm announced Sunday evening. Tabbed a 'TDN Rising Star' following his 13 3/4-length debut victory at Gulfstream Park last March, the dark bay colt was second--beaten just a half-length by Dornoch (Good Magic)--in the GI Belmont Stakes in just his third trip to the post. He was second again after recovering from a stumbling start in the GI...