Complex sentence: Engineering Animation, Inc. (EAI) was a services and software company based in Ames, Iowa (the silicon prarie) from it's incorporation in 1990 until it was aquired by Unigraphics, Inc in 1999.
Split into simpler sentences: Engineering Animation, Inc. (EAI) was a services and software company based in Ames, Iowa (a.k.a. the "Silicon Prarie"). It remained headquartered there from its incorporation in 1990 until it was aquired by Unigraphics, Inc. in 1999.