Tablets shipments will blast ahead by 53 percent in 2013 as desktop and laptop shipments decline by 11 percent, research firm Gartner forecast on Monday. The emergence of ultramobile devices, which marries a PC with the form factor of a tablet, will help ease the declines in other PCs, but not by much. When ultramobiles are included, the overall PC market will still decline 8.4 percent in 2013, Gartner said.