The North Korean Threat - Bill Whitaker reports from Seoul,where 28,000 U.S. troops are stationed in or nearby, and theKorean DMZ, seeing firsthand the tense standoff between theNorth and South.Brain Hacking - Silicon Valley is engineeringyour phone, apps and social media to get you hooked, says aformer Google product manager.Bruno Mars - He's been broke,busted and nearly homeless. Now, as 60 Minutes' Lara Loganreports, he's on top of the music world.