The rising mercury in Southern California was the hot topic of conversation at a Breeders' Cup World Thoroughbred Championships news conference held Thursday following training hours at the Arcadia, California racetrack.Trainers Bruce Headley, Scott Lake, Ted West and owner Jack Knowlton of Sackatoga Stable were all in agreement that Saturday's predicted high temperature of at least 90 will have at least a small effect on the majority of runners on Racing's Championship Day. "Horses are temperature sensitive," said West, who will saddle Jeff Sengara's Bluesthestandard in the Breeders' Cup Sprint (gr. I). "(Local horses) could possibly have a little edge, but it's going to be hard on us too." Scott Lake agreed, saying, "We shipped in 12 days in advance and (Sprint candidate Shake You Down) has acclimated well," adding that he believed the late shippers to be at the very least a little disadvantaged. (The local horses) do have a slight advantage because horses are affected by nature," said the veteran Headley, who sends out Got Koko in the Breeders' Cup Distaff (gr. I). The high temperature forecast for Saturday in Arcadia is 89 with high winds.