"More residents of Northern California mountain communities were told to leave their homes on Thursday after an out-of-control wildfire doubled in size overnight, scorching more than 100 square miles of drought-parched timber and brush."

"President Barack Obama will highlight strides the United States has made on climate change when he addresses a major U.N. climate summit next week, senior administration officials said on Thursday."

"The Obama administration on Thursday announced measures to tackle the growing threat of antibiotic resistance, outlining a national strategy that includes incentives for the development of new drugs, tighter stewardship of existing ones, and improvements in tracking the use of antibiotics and the microbes that are resistant to them."

"Banamichi, Mexico - Liseth Mendez and Judas Barrios milk two cows covered in a cloud of tiny persistent flies as the sun taints in red the surrounding mountains near a ranch less than a kilometre from the Sonora River."

Researchers are finding increasing evidence that environmental factors -- ranging from exposure to toxic chemicals to physical and mental exercise -- can have important effects on aging brains. While older people may have a surprising capacity for neurological regeneration, chemical exposures (even exposures earlier in life) have been linked to neurological disorders such as Alzheimer's and Parkinson's diseases.

"New York City children exposed in the womb to moderate levels of two plasticizers had a 72 to 78 percent higher chance of developing asthma, according to a new study published [Wednesday]."

"It's like Florida's version of The Blob. Slow moving glops of toxic algae in the northeast Gulf of Mexico are killing sea turtles, sharks and fish, and threatening the waters and beaches that fuel the region's economy."