“Even if we’ve made really serious progress in the fight against AIDS, the glass is half full. We still have a long way to go,” said UNAID's Peter Piot. Piot's been on the front lines of the fight against AIDS in Africa for three decades.

A new method for toxicity testing - employing robots - could one day make the need for lab animals obsolete. Read more about how robots replace animals.

Even before birth - and throughout life - all animals yawn. But scientists are still unclear about why. Robert Provine, a neuroscientist at the University of Maryland in Baltimore, has studied yawning for over 30 years. Read 'Why do we yawn?'

Much of Earth's population today depends on rice for food. In the fight against world hunger, David Salt of Purdue University in Indiana is looking for the genes that regulate micronutrients and trying to create a nutrient-packed rice plant. Read more on how we can make rice healthier.

A friend and I were on the outskirts of Taos, New Mexico a few years ago and became curious about a strange-looking community in the distance ... Read more about earth ships.

It's a paradox in our mostly sedentary lifestyles that when we actually exert physical energy, it's wasted. Read more in 'Paddle your treadmill: A treadmill that floats?'

Vinegar talks about a new, more eco-friendly oil recovery process that uses giant underground heaters to help thick, old oil flow more freely.

Anyone who has been to Maui or driven across West Texas has seen a wind farm, where great rows of gigantic spiraling windmills turn silently in response to unseen air currents.

After a mosquito sucks your blood, you're left with a bit of mosquito saliva in your body, and it causes a mild allergic reaction - an itchy, red bump. Read more about the red bump on your mosquito bite.

He said humans have experienced catastrophes in the past, but that the events of this century could determine the survival of our species. Read more about global catastrophic risks.