Chromosome-protecting telomeres are shorter in people with depression--which has been linked to irregular stress hormone levels. Katherine Harmon reports

The Keystone XL pipeline wouldn't be a major environmental calamity, but oil addiction is. David Biello reports

After a heart attack, cells from the patient's bone marrow can help improve heart function. Katherine Harmon reports

The fate of an island chain's president may mean more--or even less--progress to combat climate change. David Biello reports

A smart-phone app in development for depression patients tracks contacts and movement, and prompts activities when patterns show withdrawal. Katherine Harmon reports

A new system combines the power of plants and photovoltaics to make solar power cheap and durable. David Biello reports

Manuka honey stopped a skin strep in its tracks. Katherine Harmon reports

Battery chargers are everywhere these days, wasting electricity. California aims to change that. David Biello reports

Scientists are uncovering more and more evidence that the air in buildings can be bad for you. David Biello reports