Claude Lévi-Strauss has Died [Greg Laden's Blog]
When I was first reading about Anthropology as a budding Archaeologist, Claude Levi Strauss was old. When I went to graduate school, I was shocked to see Claude Levi Strauss walking around at conferences, being old and revered. Every decade or so since then Claude Levi Strauss would show up in one place or another. And now, at the age of 100, he has died.
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AGU Workshop on Communicating Climate Change: Media, Dialogue, and Public Engagement [Framing Science]
For their upcoming annual meetings in San Francisco, the American Geophysical Union is sponsoring a pre-conference workshop introducing scientists, public information officers, journalists, and other attendees to several areas of social science research that examine dimensions of climate change communication and public engagement.
Below the fold are the details and the conference page is here. You can sign up for the workshop by visiting this page. It promises to be a great event and I am looking forward to the ideas, connections, and discussion that it generates.
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Mid-continent earthquakes are often aftershocks of centuries-old tremors [Not Exactly Rocket Science]
Small earthquakes in unexpected locations are often a cause for concern. The worry is that these rumbles are harbingers of bigger quakes to come. But not always - a new study suggests that many of these tremors aren't warnings, but aftershocks. In particular, those that happen in the middle of continents, far away from the major fault-lines that separate tectonic plates, probably reflect past quakes rather than future ones.
Earthquakes are a common occurrence on the boundaries between tectonic plates, and they occur at predictable spots. But they can often strike areas that are far away from such boundaries and where old fault-lines have seen little seismic activity over the past hundred years. The central United States, for example, experiences many such unexpected tremors.
But Seth Stein from Northwestern University and Mian Liu from the University of Missouri think that many of these small quakes are aftershocks of two bigger magnitude-7 tremors that shook the Midwest around 200 years ago.
The first hit a town called New Madrid in 1811 and triggered three shocks of similar magnitude that, together, reactivated an ancient set of faults in the continent's interior. The second big one hit Charleston, South Carolina in 1886. Low-level seismic activity in both areas, New Madrid and Charleston, is often interpreted as a sign that they will once again be hit by large earthquakes in the future, painting two imaginary bull's-eyes of risk in middle America.
New Madrid afer the 1811 quake
Large earthquakes are often followed by aftershocks, the result of changes in the surrounding crust brought about by the initial shock. Aftershocks are most common immediately after the main quake. As time passes and the fault recovers, they become increasingly rare. This pattern of decay in seismic activity is described by Omori's Law but Stein and Liu found that the pace of the decay is a matter of location.
At the boundaries between tectonic plates, any changes wreaked by a big quake are completely overwhelmed by the movements of the plates themselves. At around a centimetre per year, they are regular geological Ferraris. They soon "reload" the fault, dampen the aftershocks, and return the status quo within 10 years. In the middle of continents, faults move at less than a millimetre every year. In this slow lane, things can take a century or more to return to normal after a big quake, and aftershocks stick around for that duration.
Stein and Liu's study could help scientists to more accurately predict the risk of future earthquakes, especially in unexpected areas. If they're right, then it would be positively misleading to base such assessments on small quakes that could sometimes be aftershocks of historical events. In the longer term, Stein and Liu predict that such approaches will "overestimate the hazard in some places and lead to surprises elsewhere". The disastrous earthquake that hit China's Sichuan province in May 2008 highlights the catastrophic impact that unexpected mid-continent quakes can have.
To begin with, we need to better understand the network of faults that criss-crosses continents. Fortunately, such work is already underway. Palaeoseismology - a field of research that reads traces left by prehistoric earthquakes - is providing a much longer history of tremors than our pitifully short records do. Meanwhile, GPS mapping can reveal places where plates are being deformed. These are the sorts of data that will allow us to separate the aftershocks of earthquakes past from indicators of future quakes.
Again, New Madrid proves the principle - a cluster of large earthquakes hit the area in the past thousand years, but the crust shows no sign of recent deformation according to two decades of GPS measurements. It seems that recent activity really is the legacy of centuries-old quakes, a threat that has since shut down.
Reference: Nature doi:10.1038/nature08502
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Science bloggers to discuss "GMOs" with Michael Pollan [Tomorrow's Table]
The Changemakers international online community selected biofortified, a group website devoted to providing factual information and fostering discussion about plant genetics, especially genetic engineering, as the grand prize winner in the GMO Risk or Rescue Competition. This would not have been possible without the leadership of Karl Haro von Mogel, graduate student and blogger Anastasia Bodnar, our Australian colleague David Tribe and the votes of the science blogging community. Thanks all.
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As usual, the press gets it all wrong [Greg Laden's Blog]
People deride Americans for being politically sloppy thinkers, and for having short memories. This derision may be well deserved, but the flakiness of American citizens in relation to politics is perhaps easily explained.
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Even without practice, sleep improves memory of movements [Not Exactly Rocket Science]
When we think of memory aids, we consider repeating what we've learned, using clever mnemonics, or breaking information down into bite-size chunks. But one of the best memory aids we have available to us is something we all do on a daily basis - sleep. Studies have found that sleep enhances our memories of facts and physical skills alike. It can even help us remember movements that we see others do.
But this only works within a short window. Ysbrand van der Werf from the Netherlands Institute of Neuroscience found that people who saw a video of someone tapping keys on a laptop remembered the sequence more accurately if they slept on it within 12 hours. Any longer than that, and the snoozing didn't boost their recall.
Van der Werf showed the video to 128 volunteers and then tested them on either the same finger-tapping sequence or a different one. The gap between video and test was either 12 or 24 hours, and some of the volunteers were allowed to sleep during the interval while others were not.
If the test sequence didn't match the ones they saw, all the recruits did equally well. But if the sequence was the same, those who managed to sleep within the first 12 hours stood out - they were 22% faster and made 42% fewer errors than their peers who either didn't sleep or who slept later. They even improved whether they had their naps during the day or in the evening.
These results parallel those from experiments where people actually had a chance to practice new skills before their naps. The big difference here is that the improvements came only after watching movements rather than actually performing them.
Van der Werf confirmed that by taking great care to ensure that his volunteers weren't actually trying out the keystrokes for themselves. While watching the video, they had to tap two different keys to keep their fingers busy. Van der Werf even measured the muscle activity in the arms of seven volunteers to rule out the possibility that they were making subtle, unnoticed finger movements.
If it's not to do with practice, it's not to do with memorising the digits themselves or the position of the keys either. If the volunteers just saw the numbers flash up on screen, or if they saw coloured squares light up in the same position as the relevant keys, they didn't become more accurate or faster when they had to replicate the sequence. They needed to actually see someone else doing it.
Van der Werf thinks that the recruits probably imagined their finger movements while watching the video, even if they didn't actually try them out. It may even involve the mirror neurons that fire when an individual performs an action and when it sees someone else doing the same action (although mirror neurons have only been properly found in monkeys, and not humans).
Either way, the results highlight the importance of a good sleep when people are trying to pick up new physical skills. This could be especially important for people who can't possibly to practice the movements in question, such as those who have suffered a stroke or broken a limb. And clearly the most important implication is that the next time I see someone doing parkour, I will immediately lie down and have a little nap. When I wake up, I will be Batman. SCIENCE!
Reference: PNAS doi:10.1073_pnas.0901320106
More on memory:
- Molecule's constant efforts keep our memories intact
- Beta-blocker drug erases the emotion of fearful memories
- 9/11 memories reveal how flashbulb memories are made in the brain
- Our brains have a vast capacity for remembering detail
- Infants remember more by 'chunking' groups
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How the Internet Enables Intimacy [The Primate Diaries]
In the latest TED Talk, anthropologist Stefana Broadbent suggests that the technologies of social media--such as blogs, facebook, and twitter--are actually promoting greater intimacy between people rather than sucking time away from social involvement as is often supposed. In this unnatural environment we've constructed, with regulated time schedules, overseers--er, I mean, bosses--and artificial friendliness mandated as professional behavior, we long to reach out and connect with a community we identify with. In the short talk below, she suggests that this technology allows us to escape, even momentarily, and connect on a human level.
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Lashing out at Latisse® [Terra Sigillata]
I am running out of eyelash puns having written at least six posts since the summer of 2007 on a class of anti-glaucoma drugs that have been harnessed for their cosmetic side effect: promotion of eyelash growth. Bimatoprost (Lumigan®) and latanoprost (Xalatan®) are members of the prostamide class of drugs that can manage some forms of glaucoma by reducing intraocular pressure. When administered as eye drops, the drugs mimic the effect of endogenous prostaglandin PGF2α, acting as a local hypotensive to promote outflow of aqueous humor from the eye through the trabecular meshwork.
Invoking the tagline of one of my pharmacology profs, "today's side effects are tomorrow's therapy." From the prescribing information for Lumigan® brand of bimatoprost (PDF):
Lumigan® may gradually change eyelashes and vellus hair in the treated eye; these changes include increased length, thickness, and number of lashes. Eyelash changes are usually reversible upon discontinuation of treatment.
This effect was picked up first by cosmeceutical companies that began marketing chemical relatives of the prescription drugs as eyelash rejuvenators, only to have action brought against them by the US FDA. FDA does not recognize "cosmeceuticals" as a product class but stepped in because cosmetics companies were selling unapproved drugs.
About the same time, Allergan, manufacturer of the Lumigan brand of bimatoprost, sought approval for a product called Latisse, comprised of the same compound but applied to the eyelash line with a sterile brush rather than into the eyes as ophthalmic drops. FDA regulates this latter product because it was approved to treat hypotrichosis, the lack or paucity of eyelashes. Nevertheless, it is clearly being sold as a cosmetic judging from their website's "Eye Candy" tab and video advertisement with Brooke Shields.
I can't watch the time-lapse segment of the advert without thinking of a Saturday Night Live parody where the lashes would continue growing incessantly.
Today, several medium-circulation national newspapers picked up on a 27 October blogpost by Julie Deardorff (Julie's Health Club) of the Chicago Tribune where she pointed out that Allergan has had some difficulty with FDA regarding their incomplete disclosure of potential side effects in commercial advertising materials.
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U.N. to pull out 900 staff from Afghanistan: source (Reuters)
KABUL, Nov. 4, 2009 (Reuters) -- The United Nations will evacuate 900 of its international staff from Afghanistan starting Thursday, citing security concerns, a U.N. source in Kabul said. ... > read full story
Countrywide ex-CEO Mozilo must face SEC fraud case (Reuters)
NEW YORK/LOS ANGELES, Nov. 4, 2009 (Reuters) -- A federal judge rejected a request by Angelo Mozilo, the former chief executive of mortgage lender Countrywide Financial Corp, to dismiss a U.S. Securities and Exchange Commission lawsuit accusing him of securities fraud and insider trading. ... > read full story