A dangerously low oxygen level—usually below 92%—can cause shortness of breath, confusion, chest pain, or fainting. It’s often triggered by lung or heart conditions like COPD, asthma, or heart ...

Researchers Jeff Crooks and Stephany Garcia checked the minnow traps left at the murky mouth of the Tijuana River on a sunny October morning. They didn’t expect any catches. They haven’t had any for ...