LINCOLN, Neb. (AP) ¿ Perot Systems Corp. is laying off 54 of its roughly 900 workers in Lincoln as it shifts the work done in that office to a more high-tech specialty. Spokesman Joe McNamara said Thursday the layoffs were not related to Dell Inc.'s pending acquisition of Perot. Perot's employees in Lincoln do administrative and business services for insurance companies. The company is adding infrastructure services jobs there, which require different skills. McNamara says the employees who were laid off received severance, but he declined to discuss the details. Earlier this year, Perot also laid off about two dozen employees because of reduced demand from insurance companies. Perot is based in Plano, Texas. Dell is buying Perot for roughly $3.9 billion.