<http://schema.org/dateModified>
"2014-01-23T18:09:58-05:00"^^<http://schema.org/Date>
<http://www.upi.com/Science_News/Technology/2014/01/23/New-atomic-clock-accurate-to-1-second-over-5-billion-years/UPI-49921390518598/?spt=rln&or=3>