CBCradio

Past Episodes: April 2010 Archives

Saturday April 24, 2010

Pitch Lake, Cutting a Guy Some Slack, Dinosaur Diversity Disappointment, Winging in the Rain, Hungry for Life

Download this episode.


Pitch Lake

Pitch Lake
Sticky habitat

Your first mental picture of a lake in a tropical resort island like Trinidad and Tobago probably couldn't be more different from Pitch Lake. Pitch Lake is a bubbling, stinking, sticky deposit of degraded petroleum that's been mined for more than a century for road-asphalt. It turns out, though, that Pitch Lake is also alive. Dr. Steven Hallam, a professor of Microbiology and Immunology at the University of British Columbia, is part of a team that analyzed the warm tar from Pitch Lake for life. He found DNA traces of a surprising range of microbes - bacteria and archea - that were thriving in an environment that could be considered a natural toxic waste dump.


Listen to this segment: 

Download Flash Player to view this content.


Related Links


Cutting a Guy Some Slack

Medaka spawning
Medaka spawning, courtesy Lia Clark

The male Japanese medaka fish performs an elaborate courtship ritual for the many females it is trying to impress and convince to mate. But the courtship, and the actual mating with as many as twenty females in one day, is energetically expensive and results in the male being exhausted. The male shows a lack of interest through decreased courtship and a decrease in its ability to fertilize the female's eggs. A new study by Dr. Laura Weir, a post-doctoral research fellow in the Department of Biology at Simon Fraser University in Vancouver, has found that the female picks up on these cues and is very understanding. The female responds by decreasing the number of eggs she makes available for the tired male to fertilize.

Listen to this segment: 

Download Flash Player to view this content.


Related Links


Dinosaur Diversity Disappointment

hadrosaurs
Artists' impression of Hadrosaurs - Heinrich Harder

From tiny, feathered proto-birds to titanic sauropods, from armoured behmoths to swift-running vicious predators, from meek duck-billed herbivores to gigantic T-rex, the range and diversity of dinosaurs is incredibly impressive. But dinosaurs trod the planet for more than a hundred million years, and our perspective may be deceiving us, as to their diversity at any one time. Dr. Hans Larsson, from The Redpath Museum at McGill University, has done a reconstruction of dinosaur diversity during the last few million years of their existence - right before their extinction 65 million years ago. He studied a vast swath of North America, from Louisiana to Saskatchewan, and found that there just wasn't much regional diversity at all. The dinosaurs were a pretty homogenous, generic group over this vast area of their habitat.

Listen to this segment: 

Download Flash Player to view this content.


Related Links


Winging in the Rain

Manakin
Manakin and a swollen waterfall, Dr. Alice Boyle

Most birds that migrate do so in the pursuit of better feeding grounds. Many even travel thousand of kilometres to reach their final destination. But the White-ruffed Manakin, a tropical bird that lives in the mountains of Costa Rica, is different. A new study by Dr. Alice Boyle, a post-doctoral fellow in the Department of Biology and the Advanced Facility for Avian Research at the University of Western Ontario, has found that food and distance are not critical to Manakin migration. The Manakin simply migrates about 20 kilometres up and down the mountain on which it lives, to get out of the more than nine metres of rain that falls in the higher elevation during the rainy season.

Listen to this segment: 

Download Flash Player to view this content.


Related Links

external site - links will open in a new windowPaper in Proceedings of the Royal Society Biology
external site - links will open in a new windowNews release from UWO
external site - links will open in a new windowStory at ScienceNow
external site - links will open in a new windowDr. Boyle's web site




Hungry for Life

Oliver twist requesting more gruel
Denying Oliver more gruel might have done him a favour

We're all familiar with the most basic advice for a longer, healthier life: eat less, and exercise. But it may be the case that you can have an even longer life by tweaking that recommendation slightly: skip the exercise and eat much, much less. The science of Caloric Restriction - reducing food levels to just above the level of malnutrition or starvation - has been developing for the past twenty years. First in simple micro-organisms, then in rodents and even primates, researchers have found that reducing food intake substantially can extend lifespan by huge amounts - in rodents by 30-40%. The animals seem healthy and active and have much lower risk of aging-related illness like diabetes, cardiovascular disease and even cancer. A small group of human enthusiasts has been experimenting with calorie restriction - reducing their food intake by up to 30%. Dr. Luigi Fontana, a professor of medicine at Washington University School of Medicine, and the Director of the Division of Nutrition and Aging at the Italian National Institute of Health, studies caloric restriction, and specifically the people who have been practicing it. He says that they seem to be experiencing considerable benefit. It's too early to tell whether their lives will be longer, but they do seem healthier - with lower blood pressure and lower levels of biological markers for heart disease and diabetes. Dr. Fontana says we're beginning to understand the biology of how this works, which may allow us to harness some of the benefits of caloric restriction without risky and dramatic alterations to our diet

Listen to this segment:

Download Flash Player to view this content.

Related Links



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

Saturday April 17, 2010

Silent means Deadly, Caterpillars Walk the Talk, Mysterious Eclipse, Devon Ice Cap Loses its Cool, The Anthropocene - the Epoch of Humans, Science Fact or Fiction: Grey Hair

Download this episode.


Silent means Deadly

crickets.jpg Cricket getting silencing surgery, courtesy D. Logue

When crickets fight, there's a lot of noise. Not just the clashing of mandibles and the clicking of legs, but the cricket equivalent of "trash talking" as well. Dr. David Logue, a biologist at the University of Puerto Rico and his colleagues from the University of Lethbridge in Alberta, were interested in what would happen when the crickets couldn't make the sounds associated with their fights. What they saw was mayhem. Crickets, who were either naturally silent or had their noisemakers removed, fought viciously, longer, and more violently than those full of sound and fury. Apparently, these insects use bluster not to provoke, but to avoid violence.

Listen to this segment:

Download Flash Player to view this content.


Related Links


Caterpillars Walk the Talk

caterpillar_yack.jpg Masked birch caterpillar (Drepana arcuata) courtesy J. Yack

The masked birch caterpillar wards off its rivals in a couple of different ways; it drums its jaw against the leaf on which it lives, and it drags its anus to make a scraping noise. Dr. Jayne Yack, a neuroethologist in the Department of Biology at Carleton University in Ottawa. believes that jaw drumming evolved from the more primitive territorial rituals of biting, butting and hitting. Anal scraping evolved from walking, as in crawling in the direction of intruders to attack them. Aggressive movements toward rivals have become ritualized into signals that have evolved to avoid physical confrontation and injury.

Listen to this segment: 

Download Flash Player to view this content.

Related Links

external site - links will open in a new windowPaper in Nature Communications
external site - links will open in a new windowNews release from Carleton University
external site - links will open in a new windowDr Yack's lab
external site - links will open in a new windowNot Exactly Rocket Science blog (with video)


Mysterious Eclipse

mystery_eclipse.jpg Photograph courtesy John D. Monnier, U of Michigan

For the first time, astronomers have observed the mysterious dark companion in a binary star system that has been a puzzle for more than 175 years. In 1821, the star Epsilon Aurigae was discovered to be an eclipsing double star system; its eclipse happens every 27 years and lasts nearly two years. Astronomers theorized that the second object was a star so dim that its own light wasn't visible from earth. In turn, they believed it was being orbited edge-on by a thick disc of dust. Using new technology developed at the University of Michigan, astronomer Dr. John Monnier has new images that show this is exactly the case. A dark, dense, but partially translucent cloud can be seen passing in front of Epsilon Aurigae.

Listen to this segment: 

Download Flash Player to view this content.


Related Links



Devon Ice Cap Loses its Cool

belcher.jpg Ice and rock dominate the landscape on the Devon Island ice cap, photo by Brad Danielson

The Devon Ice Cap is about 14,000 square kilometers in area, as much as 880 meters thick - the second largest ice mass in the Arctic, after the Greenland Ice Cap - and apparently shrinking by the minute. Dr. Sarah Boon, a geographer from the University of Lethbridge, led a group that's been studying this huge mass of ice on Devon Island, and their latest work indicates that the ice cap has been losing mass since 1985. This is worrying, but they hope understanding the ice of Devon Island better might provide insights into the more important dynamics of the much bigger Greenland Ice Cap.

Listen to this segment: 

Download Flash Player to view this content.


Related Links

external site - links will open in a new windowPaper in Arctic (direct pdf link)
external site - links will open in a new windowNews release from Arctic Institute of North America
external site - links will open in a new windowDevon Ice Cap study project
external site - links will open in a new windowDr. Boon's web site


The Anthropocene - the Epoch of Humans

apollo17_earth.jpg

Many geologists think that we have now entered a new geological interval of time. Humans have had such a tremendous impact on the Earth, that we've made ourselves geologically distinct. Physically, with our digging, building, and damming; biologically, with the way we've changed the very species that live on the planet; and chemically, with the traces we'll leave in the rocks formed from the sediments we deposit today, we're creating our own layer in the geological history of the planet. A new name has been proposed for this new geological epoch - the Anthropocene. Dr. Jan Zalasiewicz of the Department of Geology, University of Leicester, has been part of a committee of geologists who are proposing the idea of our time as part of the official geological time line. He thinks it's clearly scientifically based, but that it also confirms the scale of impact that we humans have had on our planet.

Listen to this segment: 

Download Flash Player to view this content.


Related Links



Science Fact or Fiction - Grey Hair


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 was submitted to us by Ellen Wardell of Saskatoon: "Stress causes your hair to turn grey." To get to the roots of this issue we've contacted Dr. Jason Rivers, a clinical professor of dermatology at the University of British Columbia.

Listen to this segment: 

Download Flash Player to view this content.





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

Saturday April 10, 2010

Make Pee, Not War, Wat was Up With Angkor, Venusian Vulcanism, Bright Ideas - 50 Years of Lasers

Download this episode.


Make Pee, Not War

crayfish.jpg Urine Trouble, courtesy Fiona Berry; BMC Biology

In the signal crayfish species, urine is the key to communicating aggressive intentions. But the female urine has a dual purpose. Dr. Fiona Berry, formerly at the University of Hull in England, and now with the conservation group Natural England in York, has found the meaning of the female's mixed messages. The female releases a puff of urine in the presence of the male. The male is able to recognize a chemical in the urine that tells him two things. One is an aphrodisiac signal that says she's ready to mate; the other is an aggressive message to the male that says, "if you want to mate, show me how tough you are." This way, the female is assured of mating with the toughest, fittest male.

Listen to this segment:

Download Flash Player to view this content.

 
Related Links



Wat was Up With Angkor?

angkor_wat.jpg Angkor Wat, copyright Manfred Werner, cc-by-sa-3.0

The ancient city of Angkor was the seat of the Khmer empire that dominated Southeast Asia for centuries. Its mysterious decline in the 14th and 15th centuries has puzzled historians. But new work reconstructing the climate of the region may suggest part of the solution to that mystery. Dr. Brendan Buckley, a research scientist at the Lamont Doherty Earth Observatory of Columbia University in New York, and his group, used growth records preserved in tree-rings to show that Angkor would have suffered decades-long droughts, interspersed with unusually intense monsoons. This boom-bust cycle would have been extremely destabilizing for Angkor, which depended on a complex system of canals and reservoirs for water.

Listen to this segment:

Download Flash Player to view this content.


Related Links


Venusian Vulcanism

venus_volcano.jpg Infrared picture of the volcanic peak Indunn Mons, courtesy NASA/JPL-Caltech/ESA

Venus had veritable vistas of volcanoes in its past. We learned from the Magellan spacecraft, which mapped the Venusian surface with radar, that giant volcanoes and lava flows had shaped Venus' surface. But there were no signs to indicate whether Venus was still volcanically active. Now, a team using an instrument on the European Space Agency's Venus Express spacecraft has found signs of volcanic flows that are only hundreds of thousands to a couple of million years old - practically brand-new in geological terms. Dr. Suzanne Smrekar, a research scientist at NASA's Jet Propulsion Laboratory in California, and her team, found rock with a characteristic heat signature that indicated that it was from a relatively fresh volcanic flow.

Listen to this segment:

Download Flash Player to view this content.


Related Links



Bright Idea: 50 Years of the Laser

laser.jpg The first Laser

The next time you play a DVD, go through the check-out at the grocery story or just make a phone call, you'll be using one of the most important inventions of the 20th century - but one that you can't always see. It's crucial to modern communications, industry, medicine and science. And fifty years after its invention, people are still finding new uses for it. The laser has come a long way in its first 50 years. At the time of its invention, many people called it a solution looking for a problem. And like many great inventions, the laser began as an idea, starting with Einstein, then became a competition among scientists to be the first to make one that actually worked. That race was won on May 16th, 1960 at the Hughes Laboratories in California by physicist Dr. Theodore Maiman, who late in life moved to Vancouver where he was an adjunct professor at Simon Fraser University. Jeff Hecht, a science and technology writer and author of Beam: The Race To Make The Laser, looks at the history of the laser and the men who strove to be first.

Dr. Paul Corkum, Canada Research Chair in Attosecond Photonics from the Department of Physics at the University of Ottawa, uses a very sophisticated form of laser in his research: he developed attosecond laser pulses - flashes of light so short that they can provide images of electrons moving around atoms. He explains how the laser works and some of its applications for the future.

Listen to this segment:

Download Flash Player to view this content.


Related Links




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