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Some science news stories below…

[ Image of DNA molecule http://en.wikipedia.org/wiki/DNA ]

CO2 and temperature change together at end of last glaciation

A new technique uses isotopes of nitrogen to date the age when bubbles of air are trapped in ice.The oldest ice in Antarctica contains bubbles almost a million years old- the deeper the ice, the older the gas in the bubbles.

These bubbles are used to measure CO2 in the atmosphere, and are compared with temperature calculated from isotope measurements of hydrogen in the water molecules of ice. Previous studies showed that the temperature increased first, and then the amount of CO2 in the atmosphere increased about a millenium later.

The latest study examines ice from between 20 and 10 thousand years ago when the ice sheets were shriking. It corrects previous studies by taking account of the time it took the bubbles to be isolated from the atmosphere. Results show CO2 and temperature change together (within a century) and it is not clear whether CO2 or temperature increased first. Report in Science reported in New York Times

Temperature, CO2 and methane changes 20-10 thousand years ago

Temperature, CO2 and methane changes 20-10 thousand years ago
Image: Science

Mediterranean diet study shows lower heart disease compared with low fat diet

A study in Spain looked at 7500 older people at high risk of heart attacks and strokes. They were directed to follow 3 different diets- a ‘Mediterranean’ diet with either added nuts or olive oil, or a low fat diet. The low fat diet was difficult for people to follow, and was little different from their normal diet. The Mediterranean diet consisted of olive oil, nuts, fruit, vegetables, fried tomato sauce, legumes, fish, white meat and wine, as well as avoiding soda, cakes and biscuits, red and processed meats, and dairy

The Mediterranean diet group had a 30% lower incidence of heart attacks and strokes (see graph below) over the 5 years of the study (reducing the risk by 3 heart attacks or strokes per 1000 person-years). It is uncertain whether the results would also apply to younger people at lower risk. Original report New England Journal of Medicine reported in New York Times

Mediterranean and control diet outcomes
Image: New England Journal of Medicine

Planet found orbiting nearest star

Alpha and Beta Centauri Image: Wikipedia

Using a 3.6m telescope in Chile, researchers have detected wobbles in the movement of one of the stars in our nearest star system. The wobbles indicate a planet about the same mass as the Earth. It is orbiting much closer to the star, Alpha Centauri B, and so is much hotter than Earth, about 1200C. Most exoplanet systems contain more than one planet, and it is hoped more may be found around the same star. It is 4 light years away, so still a 75000 year journey at the speed of the fastest spacecraft. Research Paper in Nature, BBC News article

Arctic sea ice minimum

Arctic sea ice was its lowest ever in 2012, reaching a record minimum in mid-September, according to data from the National Ice and Snow Data Center. Now around half its average extent compared with the 80s and 90s, the change is likely to have a significant effect on weather in the northern hemisphere. Reduced cooling from reflective ice accelerates warming of the polar region, and affects airflow and rainfall patterns in Europe and North America.