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He received a B.S. in mechanical engineering from Northwestern University in 1988 , an M.S. in engineering-economic systems from Stanford University in 1989 and a Ph.D. in political science from Duke University in 1998 .
 organization: Northwestern University; organization: Stanford University; organization: Duke University
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 organization: Northwestern University; organization: Stanford University; organization: Duke University