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Boston bombing suspect pleads not guilty

The CBS News Roundup: Boston Marathon bombing suspect Dzhokhar Tsarnaev pleads not guilty; George Zimmerman says he will not take the stand; the Quebec train disaster is being blamed on employee error; the Senate fails to lower student loan interest rates; Randy Travis is in congestive heart failure; and, an astronaut shows how to wash your hair in space. Nick Dietz reports on the news you need to know now.