Calls from the heart

摘要

A bomb has reduced a shopping mall to rubble, leaving rescue workers desperate to know if anyone inside is still alive. Thanks to a remarkable discovery at Bell Labs in New Jersey, they could one day find out simply by calling the cellphone of someone lying unconscious inside. That's because the signal from your cellphone reveals two of your vital signs: your pulse and breathing rate. Better still, you don't even have to answer your phone.