VANCOUVER – Sierra Wireless has narrowed its net loss to $6.8 million in the second quarter compared to $8.6 million for same period in 2010. Revenues were down to $139.9 million, a decrease of 12% compared to $159.1 million in the second quarter of 2010, and a decrease of 3% compared to $144.3 million in the first quarter of 2011. The wireless technology maker blamed the year-over-year revenue decrease on the loss of revenue from Barnes & Noble and Clearwire, which together accounted for nearly $25 million in revenue in the second quarter of 2010.Mobile computing revenue was $66 million,...