* Exercise your Aging Brain * Super Salmon * Mummified Forest * Saturn's Rippled Rings * Science Fact or Fiction - Snowflake Clones *

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Exercise your Aging Brain

brain.jpg It must be old - it's so wrinkled!
Evidence has been accumulating for a decade now that the best way to forestall or even reverse age-related mental decline is with a regular program of exercise.  Mental decline is, unfortunately, one of the features of normal aging.  Along with losing muscle tissue, joint flexibility and bone density, we lose brain volume as we get older.  However, studies have shown consistently that people who exercise regularly can resist this decline. 

Dr. Art Kramer, a neuroscientist and director of the Beckman Institute at the University of Illinois, says this was the first indication that aging was not a "one-way street" in which everything gets worse as we get older.  He'd shown in studies that sedentary older adults put on regular aerobic exercise programs can improve their scores on cognitive function tests by 15-20%.   

Dr. Brian Christie, a neuroscientist in the Island Medical Program of the University of British Columbia and a professor at the University of Victoria, suggests that part of the reason to think mental abilities and fitness could be related is that the brain is a very demanding organ, requiring vast amounts of nutrients and oxygen.  Aging-related reductions in fitness could be depriving the brain of the resources it needs to perform well.  There is also evidence, that exercise can actually stimulate growth in the brain.  Sedentary people put on exercise programs often have increases in brain volume. 

Dr. Laura Baker, a neuropsychologist with the Veterans Administration Healthcare System and the University of Washington in Seattle, says there are many lines of research being pursued to understand how exercise helps the brain.  One promising one is evidence that exercise produces growth factors in the brain that preserve and protect neurons, and may, in fact, actually stimulate neural stem cells to produce new brain cells - restoring brain tissue that may have atrophied away. 

Dr. Jon Ratey, a psychiatrist from Harvard University, says that this is likely because stem cells in the brain are stimulated to produce new neurons.  The amount of exercise required seems to be reasonable.  Most studies indicate that forty minutes to an hour of moderately intense aerobic exercise - enough to make you sweat and breath a little harder - three or four times a week, will help you reap the cognitive rewards.

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Super Salmon

super_salmon.jpg This one can fly - courtesy Matt Casselman
Sockeye salmon have suffered declines in recent years, as climate change warms the waters of B.C.'s Fraser River.  Erika Eliason, a Ph.D. candidate in zoology at the University of British Columbia, wanted to find out why.  So she tested different groups of salmon on a "fish treadmill" in the lab, to see how their bodies respond as the water gets hotter.  She found that at least some sockeye may be fit enough to face the heat - a group of sockeye called the Chilco are "superfish" that migrate hundreds of kilometres to their spawning grounds, through raging rapids and up tall mountains during the hottest part of summer.  Eliason's study showed the Chilco have bigger hearts that seem better able to use adrenaline than other sockeye salmon, allowing them to withstand warmer temperatures.  That suggests the Chilco will fare better than other sockeye salmon as the climate gets warmer and it may be possible for the species as a whole to adapt to climate change.  

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Mummified Forest

mummified_tree.jpg The trunk of one of the mummified trees shows very narrow growth rings.  Credit: Joel Barker, Byrd Polar Research Center, Ohio State University
The polar desert at the north end of Ellesmere Island in Nunavut is a barren landscape, far above the tree line.   So when a park ranger told Alberta scientist Dr. Joel Barker that he had found some logs there, Barker had to check them out.  The logs turned out to be the mummified remains of a forest that lived up to 10 million years ago, when the Arctic was far warmer. It's the northern-most mummified forest ever found in the Canadian Arctic.  Dr. Barker, a research scientist at Byrd Polar Research Center at Ohio State University, discovered that the forest contained the well-preserved trunks, twigs, leaves, and cones of pine, spruce, birch and larch trees.  Back when the trees were alive, they were barely hanging on, as the climate cooled dramatically. Barker hopes studying them will offer hints about how trees will respond, as the Arctic climate grows warmer.   

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Saturn's Rippled Rings

sn-saturnrings.jpgCassini images of corrugations rippling across Saturn's C ring

In 2009, the Cassini spacecraft captured curious images of Saturn's C and D rings.  The images were of the sun illuminating subtle ripples that appeared as a regular series of light and dark bands across the rings, much like the way light would reflect across a corrugated tin roof.  Dr. Matthew Hedman from the Department of Astronomy at Cornell University compared the images from Saturn to similar images of Jupiter's rings being studied by other scientists at the SETI Institute in Colorado.  The ripples in both planet's rings were measured and compared to calculations of how they should evolved over time.  For Jupiter, this pointed to 1994, the date of a known comet strike.  This model indicated something similar happened to Saturn in 1983.  Because direct impact from a comet would simply punch a hole through the rings, it is believed the ripples for both planets were caused by comet debris.   

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Science Fact or Fiction - Snowflake Clones

From time to time, we'll present a commonly held idea or popular saying - and ask a Canadian scientist to set us straight on whether we should believe it or not.  Today's popular belief comes to us from Deborah Graham in Vancouver, who wonders whether "No two snowflakes are exactly alike". 

To help us separate the cold truth from the fluffy myth, we've contacted Dr. Jeffrey Kavanaugh, in the Earth and Atmospheric Sciences Department at the University of Alberta in Edmonton. He says it is science fact.

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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0