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Science Sunday #30

Posted by Don McLenaghen on January 8, 2012

– and on the seventh day we learn.
Each week I hope to give a synopsis of the interesting science stories I have heard on my plethora of science podcasts I listen to each week plus anything I pick up scanning the inter-web. This week’s top stories:

This week’s top stories:

 

Russian river freshening Canada’s north –

Blue represents maximum freshwater increases and the yellows and oranges represent maximum freshwater decreases.

The team attributes the redistribution to an eastward shift in the path of Russian runoff through the Arctic Ocean, which is tied to an increase in the strength of the Northern Hemisphere’s west-to-east atmospheric circulation, known as the Arctic Oscillation. The resulting counter-clockwise winds changed the direction of ocean circulation, diverting upper-ocean freshwater from Russian rivers away from the Arctic’s Eurasian Basin, between Russia and Greenland, to the Beaufort Sea in the Canada Basin bordered by the United States and Canada. The stronger Arctic Oscillation is associated with two decades of reduced atmospheric pressure over the Russian side of the Arctic.

“Knowing the pathways of freshwater is important to understanding global climate because freshwater protects sea ice by helping create a strongly stratified cold layer between the ice and warmer, saltier water below that comes into the Arctic from the Atlantic Ocean,” said Morison. “The reduction in freshwater entering the Eurasian Basin resulting from the Arctic Oscillation change could contribute to sea ice declines in that part of the Arctic.”

Science Daily

Eureka Alert

Nature

 Russian river water unexpected culprit behind Arctic freshening – with video

Russian River Water Unexpected Culprit Behind Arctic Freshening

 

Frankenstein monkey created from two different embryos –

The first successful birth of chimeric monkeys, monkeys developed from stem cells taken from two separate embryos, happened at OHSU’s Oregon National Primate Research Center according to a paper in Cell published by Masahito Tachibana et al.

The research was conducted to gain a better understanding of the differences between natural stem cells residing in early embryos and their cultured counterparts called embryonic stem cells. As well as compare how mice differ from primate in how their stem cells work. They were working with two kinds of cells. The first cell type was totipotent cells — cells from the early embryo that have the ability to divide and produce all of the differentiated cells in the placenta and the body of organism. These were compared with pluripotent cells — cells derived from the later stage embryo that have only the ability to become the body but not placenta.

In mice, either totipotent or pluripotent cells from two different animals can be combined to transform into an embryo that later becomes a chimeric animal. OHSU showed this to also be the case by successfully producing the world’s first primate chimeric offspring, three baby rhesus macaques named Roku, Hex and Chimero.

“This is an important development — not because anyone would develop human chimeras — but because it points out a key distinction between species and between different kind of stem cells that will impact our understanding of stem cells and their future potential in regenerative medicine,” explained Shoukhrat Mitalipov, Ph.D.

Science Daily

Eureka Alert

New Scientist

Raw Story

 Generation of Chimeric Rhesus Monkeys

OHSU research demonstrates not all embryonic stem cells are equal; produces the world’s first primate chimeric offspring

Getting old happens at a younger age –

We often associate forgetfulness and muddled thinking with the aged. We think that when we are in our 70’s we will have to brace ourselves mental decline. However, according to recent research published in British Medical Journal by Archana Singh-Manoux et all points to noticeable decline as early as 45.

In the study assessed the cognitive abilities of 7390 people at three points over a 10-year period. The participants were aged between 45 and 70 at the start of the study in 1997. At each of the three test points, the team assessed each participant on their verbal and mathematical reasoning, vocabulary and verbal memory and fluency.

The team found that individuals from all age groups experienced a decline in cognitive function over the ten year period – even those aged between 45 and 49. The suggestion that the ageing brain starts to deteriorate in the mid-forties will come as a surprise to many, particularly given a recent review that concluded such decline occurs primarily over the age of 60.

The findings suggest that early signs of dementia could be identified in people in their 40s, who may be able to start preventative therapies. Singh-Manoux agrees: “We now need to look at who experiences cognitive decline more than the average and how we stop the decline. Some level of prevention is definitely possible,”

New Scientist

CBC

BBC

Raw Story

Timing of onset of cognitive decline: results from Whitehall II prospective cohort study

 

Extraterrestrial Quasi-crystals –

What a Quasi-crystal looks like

Having escaped the realm of pseudo-science, quasi-crystals earned a Noble Prize last year. It has long been thought these ‘impossible’ items could only be produced by a very precise and complex procedure in high-tech labs. However resent research by Paul Steinhardt et al published in Proceedings of the National Academy of Sciences states that quasi-crystals showed that part of a meteorite was composed of these quasi-crystals.

The meteorite itself is believe to be 4+ billion years, older than the earth itself. The ratios of isotopes of oxygen in silicate and oxide minerals around the quasi-crystal grain are typical of minerals found in meteorites called carbonaceous chondrites. This indicates that the rock is of extraterrestrial origin and very old: virtually all chondrites formed at the birth of the Solar System. It is likely, but not certain, that the quasi-crystal grain within the meteorite is of roughly the same age. It was found entwined with a silica mineral that forms only at high pressures and temperatures — such as might be created by a collision with the chondrite body.

This seems to show that quasi-crystals may not be so rare or delicate as first thought.

Quirks and Quarks Podcast

Scientific American

Popular Science

Nature

Evidence for the extraterrestrial origin of a natural quasi-crystal

 

 

Mercury attempted assignation of earth’s life –

Death all around

There have been about 5 or so ‘great’ extinction events in earth’s history (depending on whether you consider our current race to extinction ‘great’ or not). The worst occurred about 250 million years ago and the end of the Permian period which resulted in the loss of 70% land vertebrates, 96% marine species; it even causes the only known mass extinction of insects. In the end, 57% of all families and 83% of all genera were killed.

It had been long thought that the culprit was massive volcanic eruptions that caused a one-two punch of nuclear winter via ash in the atmosphere and global warming via CO2 release. However new research, by Steve Grasby et al published in Geology,  is pointing its finger at Mercury…not the planet but the element.

“No one had ever looked to see if mercury was a potential culprit. This was a time of the greatest volcanic activity in Earth’s history and we know today that the largest source of mercury comes from volcanic eruptions,” says Grasby. “We estimate that the mercury released then could have been up to 30 times greater than today’s volcanic activity, making the event truly catastrophic.”

During the late Permian, the natural buffering system in the ocean became overloaded with mercury contributing to the loss of 95 per cent of life in the sea. “Typically, algae acts like a scavenger and buries the mercury in the sediment, mitigating the effect in the oceans,” says lead-author Dr. Hamed Sanei, research scientist at Natural Resources Canada and adjunct professor at the University of Calgary. “But in this case, the load was just so huge that it could not stop the damage.”

The mercury deposition rates could have been significantly higher in the late Permian when compared with today’s human-caused emissions. In some cases, levels of mercury in the late Permian ocean was similar to what is found near highly contaminated ponds near smelters, where the aquatic system is severely damaged, say researchers.

Science Daily

Latest Permian mercury anomalies

Earth’s massive extinction: the story gets worse

Eureka Alert

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