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Past Episodes: February 2012 Archives

Saturday February 25, 2012

* DNA Drone Delivers Drugs * Gelada Monkey Miscarriage * The Moon Rises - From the Dead * Exercise and the Aging Brain * Fact or Fiction - Baby Birds *


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DNA Drone Delivers Drugs
dna_nanorobot.jpg Image created by Campbell Strong, Shawn Douglas, and Gaël McGill using Molecular Maya and cadnano

Robots are large, and metal, and want to kill all humans, right?  Wrong!  Dr. Shawn Douglas, a a technology development fellow at the Wyss Institute for Biologically Inspired Engineering at Harvard University, and his group have developed a new kind of nano robot, smaller than can be seen by even powerful optical microscopes, and it's here to help you.  It's made of carefully assembled and folded DNA, through a process known as DNA origami, and it's designed to deliver carefully targeted payloads which can only be unlocked by chemical keys on specific cells in the body.  This makes it potentially an extremely efficient way to deliver targeted drugs, with minimal side-effects.
          
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Gelada Monkey Miscarriage
gelads.jpgFemale geladas rest with their new born infants.  Photo Credit:  Noah Snyder-Mackler
The gelada monkey is a cousin to the baboon and similar in appearance, though very different in lifestyle.  It lives in only one place in the world, the highlands of Ethiopia, and geladas are the only monkey that eats grass.  Males rule a harem of up to twelve females.  Dr. Jacinta Beehner, a Psychologist and Anthropologist at the University of Michigan in Ann Arbor has been studying geladas and she's discovered that females spontaneously abort pregnancy when new males take over the harem.  Since males tend to kill infants and newborns that are not their own offspring, Dr. Beehner thinks the females are cutting their losses.  Essentially they are ending investment in offspring in-utero that have no future.  The miscarriages in geladas may in part be triggered by the psychological stress of having the aggressive new male around.                

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The Moon Rises - From the Dead

lunar_graben.jpgLRO images show lunar "stretch marks"
The Moon seems a quiet, grey and dead object, and indeed many scientists had believed that the moon is geologically dead - its core had cooled off so long ago that there couldn't possibly be any tectonic activity.  However recent images taken by NASA's Lunar Reconnaissance Orbiter tell a different tale, according to Dr. Tom Watters, a planetary scientist from The Smithsonian Institution's Centre for Earth and Planetary Studies in Washington.  Among the photos are pictures of about a dozen narrow trench-like features known as graben on the lunar surface.  He believes the graben trenches are a young formation - less than 50 million years old - and evidence that the lunar crust has stretched.  This tectonic activity, which is slightly expanding the surface of the moon in these areas, may still be happening today.  

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Exercise and the Aging Brain

brain_wrinkled.jpgIt must be old - it's so wrinkled!
(Originally broadcast April 2, 2010)

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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Fact or Fiction - Rescuing Baby Birds

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 is - "Birds abandon their young at the slightest human touch"  To help us with this matter, we've contacted Dr. Bridget Stutchbury, a Professor Of Biology at York University in Toronto, and author of Silence of the Songbirds.  She says its science fiction.

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


Saturday February 18, 2012

* Under Antarctica's Ice * Anti-biotic Booze * No Kidding Around *Light Echoes * Guitar Zero *

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Under Antarctica's Ice
Vostok_drill.jpg Artist's impression of the Lake Vostok drilling project, courtesy US National Science Foundation.

Last week Russian scientists announced that, after years of work, they'd managed to drill through more than three and a half kilometers of the Antarctic Ice Cap to reach Lake Vostok.  Lake Vostok is the largest of a family of what are known as "sub-glacial" lakes that somehow persist under the ice cap.  Many are thought to have been sealed off from the rest of the Earth's biosphere for millions of years, and they could contain exotic forms of microbial life unlike anything else on the planet.  Dr. John Priscu, a professor of Ecology at Montana State University, has collaborated with the Russian Scientists in planning exploration of Antarctica's sub-glacial lakes.  He's also the leader of an American expedition that will be drilling into another of these sub-glacial lakes, Lake Whillans, next year.
          
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Anti-biotic Booze
When fruit flies are infected by a parasitic wasp, they reach for their own unique solution to the problem.  These wasps lay their eggs in fruit fly larvae.  When the wasps hatch, they eat the fruit flies from the inside out.  A new study by Dr. Todd Schlenke, an Assistant Professor in the Biology Department at Emory University in Atlanta has found that fruit flies have evolved a form of self-medication.  They seek out foods like rotting and fermenting fruit, that contain alcohol, and the alcohol kills off the wasp parasite.  The fruit fly has a tolerance to fairly high levels of alcohol, but consumption of foods with levels as low as 6 percent are still enough to kill the parasite.  Dr. Schlenke is curious as to whether alcohol may be useful in fighting some parasitic infections in humans.

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No Kidding Around

baby-2012-02-18.jpg I don't think he trusts you...  courtesy Kaelandouglas
Babies know when they are being tricked, and they don't like it.  A recent study by Ivy Brooker, a PhD student in the Department of Psychology at Concordia University in Montreal found that babies between the age of 13 and 16 months can make a distinction between a trustworthy source and one that is not trustworthy.  In an experiment some babies were tricked by an adult into believing they were being given a toy, while others were given the toy by the adult.  The result was that those babies who were fooled were unlikely to trust the same adult in a follow-up experiment.  The study is something of a surprise, as it shows that babies at this age are more adept at learning from others than had been previously thought.

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Light Light Light Echoes Echoes Echoes

etacar_hst.jpgEta Carinae is shedding matter.  Image from Hubble Space Telescope
More than 150 years ago a previously invisible star bloomed into the second-brightest star in the sky, maintaining its brightness for more than a decade, in what is known as the Eta Carinae "Great Eruption."  Astronomers at the time didn't have the tools to examine or understand the event.  Now modern astronomers are taking a look at the "light-echoes" from this event to better determine what happened to Eta Carinae.  Dr. Doug Welch, a professor of physics and astronomy at McMaster University was part of a team studying these light echoes, which are reflections of the light of the eruption off interstellar gas - essentially light that took the long path to us.  The group now thinks they have a better understanding of this event, which is a precursor to the expected supernova that will consume the star in a matter of thousands of years.

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Guitar Zero

guitar_zero.jpg
Just before his 40th birthday, Dr. Gary Marcus took up the guitar in an last desperate attempt to learn how to play music.  His approach, however, was a little different from that of most aspiring musicians.  Dr. Marcus, a psychologist at New York University, brought the tools of his work as a cognitive scientist specializing in language acquisition to his hobby.  He investigated the origins of music, how we learn it, what makes it difficult, what role talent plays in learning music, and much more.  He relates the experience in his new book, Guitar Zero: The New Musician and the Science of Learning. 
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0


Saturday February 11, 2012

* Forensic Vulturology * The Tarsier Hears * Black Hole Burps * Not-So-Dead Vents * How to Think Like a Neandertal *

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Forensic Vulturology
799px-Black_Vulture_(Coragyps_atratus)_RWD.jpg American black vulture (Dick Daniels/Wikimedia Commons)

When a human corpse is left exposed to the elements, understanding nature's effects may help forensic investigators figure out the time and circumstances of death. Clues from microbes and insects on the decomposing body are often used, but up until now forensic scientists knew surprisingly little about the impact of some much larger scavengers -- vultures. Dr. Michelle Hamilton of Texas State University San Marcos and her colleagues recently observed how vultures dealt with a donated human body. The study revealed that vultures can really mess with the body and the crime scene, potentially throwing off time-of-death estimates by months.
          
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The Tarsier Hears
Tarsius_syrichta.jpg Philippine tarsier (Plerzelwupp/Wikimedia Commons)
Tarsiers are a unique primate native to southeast Asia that are similar in appearance to some lemurs, but in fact represent a wholly different evolutionary family. These small and uncannily cute little predators have huge eyes for capturing as much light as possible, but it turns out that their ears are even more interesting. Dr. Marissa Ramsier, a biological anthropologist at Humboldt State University in California, and her colleagues have discovered that the Philippine tarsier can communicate in the high-ultrasonic -- over 90 kHz.  This is well above human hearing, and in fact very few other animals can produce or hear sound at these frequencies. Dr. Ramsier suspects that this allows the tiny animals to avoid being overheard by both prey and predators.

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Black Hole Burps

sivakoff-nasa-blackholeburp-491x284.jpg Plasma emissions from a black hole imaged using data from the Rossi X-ray Timing Explorer (RXTE) satellite and the National Science Foundation's (NSF) Very Long Baseline Array (VBLA) radio telescope. (University of Alberta/NASA)
It gobbles everything that comes near it, and then, when the meal is particularly large, emits a huge belch detectable halfway across the galaxy -- no, not your friend Jeremy at a Superbowl party, but a stellar-mass black hole. Dr. Gregory Sivakoff, an observational astrophysicist at the University of Alberta has been studying huge "burps" of high-energy particles emitted by black holes. These black holes are surrounded by accretion disks of material being drawn into the black hole, which in turn are fed by drawing off material from the black hole's companion star. In recent work he linked these "burps" to extra large "meals" being eaten by the black hole when large lumps of matter in the accretion disk fall into the black hole.

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Not-So-Dead Vents

lossy-page1-800px-East_Scotia_Ridge_-_Plos_Biol_04_tif.jpgChimneys at an active hydrothermal vent (Rogers et al./PLoS One/Wkimedia Commons)
Hot, mineral-rich water from hydrothermal vents at the bottom of the ocean supports thriving oases of life in an otherwise cold, dark barren landscape. When the vents eventually become inactive, the colonies of tubeworms, clams and other large creatures they supported disappear. Dr. Katrina Edwards of the University of Southern California took a submarine ride to a dead vent in the depths of the ocean. There, she discovered that the chemical energy spewed out by the vents continues to support huge populations of microbes long after the venting stops. The microbes feed on the mineral-rich chimneys and sediments left behind by the hydrothermal activity. These microbial ecosystems appear to be even more diverse than the populations at active vents, and could play a huge role in ocean because there are a lot more dead vents than active ones.

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How to Think Like a Neandertal

how-to-think-like-a-neandertal.jpg  (Oxford University Press)
What's going on in the mind of a Neandertal?  Prof. Thomas Wynn, an anthropologist, and Prof. Frederick L. Coolidge,  a psychologist, both from the University of Colorado at Colorado Spring, have attempted to answer that question in their book How to Think Like a Neandertal.  Prof. Coolidge suggests that Neandertals shared many cognitive abilities with humans. But he thinks archeological evidence suggests that they had important limitations in their abilities, primarily an inability to innovate and invent that developed in modern Homo sapiens. This might have been reflected in their language and communication, in their humour, and in their ability to develop large social groups, or even trade networks. These limitations might, in fact, help explain why they disappeared 30,000 years ago. When innovative, talkative, diplomatic Homo sapiens entered Europe and Western Asia, the Neanderthal's cognitive limits might have contributed to their decline.
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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0