Due to this high prevalence, vertebral artery hypoplasia (VAH) has not yet been considered an independent risk factor for ischemic stroke [1,2].
How to use your own headphones on Americanâs new 777-300ER. Passengers traveling in First and Business Class on Americanâs new 777-300ER are provided with Bose QuietComfort 15 Acoustic Noise Canceling headphones to use during the flight.
These headphones hush ambient sounds by creating frequencies that obviate the noise at your ear. They won't eliminate everything, but the better models significantly reduce the whoosh of airplanes' air-conditioning systems and crowd chatter.