President Barack Obama listens to Center for Transportation Research Director Ann Schlenker, as he tours Argonne National Laboratory in Argonne, Ill., Friday, March 15, 2013. Argonne is

 

              President Barack Obama listens to Center for Transportation Research Director Ann Schlenker, as he tours Argonne National Laboratory in Argonne, Ill., Friday, March 15, 2013. Argonne is
President Barack Obama listens to Center for Transportation Research Director Ann Schlenker, as he tours Argonne National Laboratory in Argonne, Ill., Friday, March 15, 2013. Argonne is the first US science and engineering research national laboratory, and it remains on of the nation’s largest. (AP Photo/Pablo Martinez Monsivais)