Researchers from Lawrence Berkeley National Laboratory may have discovered why so little that makes sense results from political meetings - moderately high indoor concentrations of carbon dioxide (CO₂) can significantly impair people's decision-making performance. 

In 1428 AD, while King Alfonso V was ordering Sicilian Jews into conversion sermons and the Ottomans were consolidating in Europe, the city-states of Tenochtitlan, Texcoco, and Tlacopan formed the Triple Alliance, which became the Aztec empire and ruled the Valley of Mexico until the Spaniards arrived a century later. 

The term 'Aztec' has become a little confusing since then. There were no 'Aztec' people, the people of Mexico primarily made up what were later called Aztecs, and the Aztecs were made up of many cultures, they were just dominated by conquering city-states. Historians call such a structure a hegemonic empire as compared to the traditional meaning like with Rome or Mongolia.

Giving a hard number as a critical threshold for dangerous climate change -  temperature rise below 2 degrees Celsius - has not helped climate negotiations. 

The USA, for example, has led the developed world in reducing emissions from energy, though to be fair the anti-nuclear stance of the US led to runaway emissions from the 1980s on so things are now only getting back to even there. Yet for all the emissions the US has reduced, the rest of the world has accelerated. China is the world's top polluter but has been exempt from all negotiations because it is considered a developing nation, the same goes for India and Mexico.

Citizens who were told routine health checks were too expensive and so people did not get them, to the detriment of their health and higher costs later, just got good and bad news; the good news is that a new review says people don't need them. The bad news is that will be a reason not to have them available when the Affordable Care Act goes into force.

Check-ups don't reduce overall deaths or prevent serious diseases like cancer and heart disease, according to Cochrane researchers who carried out a systematic review on the subject. They warn against offering general health checks as part of a public health program, which is the opposite of what Americans have been told by the medical community for decades.

A planet around the mass of the Earth has been found, orbiting a star in the Alpha Centauri system; the nearest to Earth and also the lightest exoplanet ever discovered around a star like the Sun.

Secondary organic materials (SOM) in the atmosphere form two distinct types, liquids and jellies, and these airborne particles have begun to react with gases in the atmosphere. In the last 20 years' research and climate modeling, these SOM particles have been assumed to drift as liquids. In a liquid phase, the organic materials would absorb other compounds like ammonia or ozone very easily and then progress through a series of chemical changes, known as chemical aging, to form particles that reflect or absorb sunlight, or form clouds.