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Thursday, January 19, 2012

Science shorts

(Note that this photo was not taken in Charlestown,
where this is an illegal act.)
By Linda Felaco 

The paradox of global warming. Now you’ve got an answer next time there’s a heavy snowstorm and some wag says “So much for global warming.” Turns out hotter summers can in fact cause colder, snowier winters. According to Judah Cohen, a climate modeler at Atmospheric and Environmental Research in Lexington, Massachusetts, average temperatures in the Arctic have been rising nearly twice as fast as in the rest of the world, while winters have grown colder and more extreme in southern Canada, the eastern United States, and much of northern Eurasia.

In a recent report in Environmental Research Letters, Cohen and his colleagues demonstrate how global warming drives regional cooling. As the Arctic has warmed, melting sea ice has increased the amount of open water in the Arctic Ocean and thus evaporation, which increases moisture in the overlying atmosphere, the researchers say. Previous studies have linked hotter summers to increased cloudiness over the ocean during the following autumn. That, in turn, triggers increased snow cover in Siberia as winter approaches. The researchers found that Siberian snow cover in October has the greatest effect on climate in subsequent months, because it strengthens a high-pressure system that steers frigid air southward throughout the winter. Incorporating this information into climate models could lead to more accurate winter weather forecasts.

Man’s best friend … and physician? Two recent genetic studies in dogs may provide clues to human disease. A skin disease in humans and golden retrievers may have a common genetic origin as well. A new study of golden retriever DNA shows that the same gene is mutated in both dogs and people suffering from one of a cluster of rare diseases that cause the skin to form scaly patches and that can sometimes be fatal, offering a much-needed clue to the disease’s origins. The study shows the power of using dog genetics to learn more about human diseases, Heidi Parker, a geneticist at the Dog Genome Project of the National Human Genome Research Institute in Bethesda, Maryland, told ScienceNOW.

The same gene that helps your dog to sit and stay
helps your toddler to do the same.
And it turns out that in a series of behavioral tests of German shepherds, researchers found that the dogs with a shortened version of a gene implicated in attention deficit disorder in humans had the most trouble controlling their impulses, regardless of their sex, age, or training, whereas the dogs with long versions of the gene passed the impulse-control tests with flying colors. The study, reported in the current issue of PLoS ONE, may not only help breeders identify hyperactive dogs but could also prove useful in studies of ADHD in humans.

Wonder if this is how Newt courted Callista. Male great bowerbirds spend most of their time building elaborate nests called bowers and surrounding them with rocks, sticks, shells, and bones to attract members of the opposite sex. The male arranges these trinkets, or “gesso,” so that the largest ones lie farthest from where the female stands such that from her perspective, the objects all appear to be the same size. 

Tiffany's for bowerbirds.
(Photo by JJ Harrison (
Turns out that the better the male manages to create this illusion, the better his chances of mating with a female. The illusion may hold the female’s attention for longer than a poorly arranged gesso, researchers suggest online today in Science, giving the male time to mate with her.

Fill ‘er up at the beach? Seaweed could be an ideal source of biofuel because unlike switchgrass and wood, it requires no land, fresh water, or fertilizer, and it has no lignin, which makes it harder to extract the sugars that ferment into ethanol. But about a third of the sugars in seaweed take the form of alginate, which industrial microbes can’t convert into ethanol. 

In work published this week in Science, researchers describe a strain of Escherichia coli that they have genetically engineered to break down and ferment alginate and all the other major sugars in seaweed into ethanol. Although it’s unclear whether enough seaweed could be harvested to make a dent in petroleum use and lower carbon emissions, experts say it’s a step in the right direction.