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Past Shows
June 10, 2006
 Download an MP3 of the entire program (22MB) (available Saturday, two hours after broadcast).
Left, Right?
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What does it mean to be a leftie? |
They’ve been vilified throughout history as gauche, sinister and wrong-headed. So what is the truth about lefties? It turns out there is little consensus among scientists about what causes handedness or what it means to be a southpaw. Some researchers believe the trait comes down to genetics. Others propose that environmental factors or brain trauma at birth might be at the root of the behaviour. We spoke to some of the few scientists digging into the causes and effects of being a lefty in a right-handed world:
Dr. Pamela Bryden is a professor of kinesiology at Wilfrid Laurier University in Waterloo.
She's found that lefties were definitely more flexible and adaptable when she measured their abilities to perform tasks with their non-dominant hand.
Dr. Amar Klar is a geneticist at the National Cancer Institute in Maryland. Dr. Klar decided to study left-handedness by heading to a shopping mall to study the hair whorls on the tops of shoppers' heads. That study led him to believe that most people inherit a single dominant gene for right-handedness, but without that gene, a person has a 50 per cent chance of being a left-hander.
Dr. Chris McManus is a professor of psychology at University College London and author of Right Hand, Left Hand: The Origins of Asymetry in Brains, Bodies, Atoms and Cultures. He believes there is a gene for right-handedness. But he thinks an evolutionary quirk occurred tens of thousands of years ago that caused a gene mutation, which Dr. McManus calls the "chance gene". It cancels the bias to the right, so those who inherit it have a 50-50-chance of ending up lefties.
Dr. Ira Perelle is a professor in the department of psychology at Mercy College in New York.
He believes there are at least three possible causes for left-handedness, including the possibility that at a very young age, a child can learn the behaviour.
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Dwarf Dinosaur
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Full-scale reconstructions of the dwarf sauropod species Europasaurus holgeri |
While examining thin sections of fossilized dinosaur bones that had been discovered in a limestone quarry in northern Germany, Dr. Martin Sander realised the fossils belonged to a new dinosaur species called Europasaurus. They resembled other sauropods from the Jurassic -- most famously, the long-necked apatosaurus (popularly known as Brontosaurus) - with one notable exception: they were only a few metres long -- a dwarf species. Dr. Sander explains that bones contain growth rings, in much the same way trees do. The growth rings in the Europasaurus bones suggest that this diminutive species grew at a much slower rate that its gargantuan relatives, and only grew to a fraction of the size. Dr. Sander suggests that the Europasaurus evolved from a much larger ancestor that became trapped on a prehistoric island. Natural selection would have favoured smaller animals that could survive on the limited food resources available on the island. It is the oldest example ever found of an island dwarf species. Dr. Martin Sander is the curator of paleontology and an adjunct professor at the University of Bonn, in Germany.
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Ancient Life Forms
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Cone-shaped stromatolites - Copyright, A. Allwood |
An Australian group has described a fossil reef system with evidence of life from nearly 3.5 billion years ago. The fossils are stromatolites which are the fossil remnants of colonies of microbes. The microbes lay down characteristic layers of sediments creating cones, blobs and other shapes. In this remarkable fossil assemblage, several kinds of stromatolites are preserved, and the researchers think this reflects an entire microbe-based ecosystem in the ancient seas. This is the strongest evidence of widespread microbial life this early in the earth's history. Abigail Allwood, a researcher in geology at the Australian Centre for Astrobiology at Macquarie University in Sydney, was a member of the research team that surveyed the fossils.
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Planemo systems
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Planemo accreting material from disk of dust - Courtesy, Jon Lomborg |
A team led by Dr. Ray Jayawardhana from the Department of Astronomy and Astrophysics at the University of Toronto has found something new happening in the universe: the formation of miniature star systems. Normal stars grow from large disks of dust in star-forming regions. These new systems, however, are too small to allow stars to form from them. So the disks of dust collapse into central objects that are the size of giant planets, perhaps with smaller planets around them. In effect, they're like a scale model of a solar system. They've been dubbed Planemos -- for planetary mass objects.
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Question of the Week: Runny Noses
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This week, we have a question that was left over from our road show in Edmonton last week.
Robert Parks from Edmonton asked: Why does my nose run when I’m outside on a cold day? And why does it stop running when I go back inside?
For the answer, we brought in Dr. Carina Majaesic, a pediatric pulmonologist at Stollery Children’s Hospital at the University of Alberta.
Last week
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