Archive for April, 2012

Why We Should Not Worry about the Mad Cow Case in California

By Sarah Zhang | April 30, 2012 12:38 pm

spacing is important

A phrase like “mad cow” is sure to whip up a media frenzy. When the USDA confirmed last week the first case of bovine spongiform encephalopathy (BSE) in six years, news headlines were splashed with reports of “mad cow disease,” the informal and scarily evocative term for BSE. What got lost in these initial reports is that this case of BSE involves a different protein than previous epidemics in Europe, and there’s no evidence that this type is transmissible to humans.

Nature News has a solid and thorough explanation of the science behind this case of BSE, known as L-type. As it happens in nature, mutations arise spontaneously, and L-type BSE is caused by a spontaneous mutation in a particular protein. A lot is still unknown about L-type, but we have never seen it spread through cow populations (or jump to humans) through ingestion. Previous BSE epidemics in Europe were spread by the admittedly gruesome practice of grinding up leftover cow parts and feeding them back to cows, but this has been long banned in the United States because of BSE. Critics have argued that there may still be indirect sources of cow protein in feed (cow protein is fed to chickens, and poultry leftovers go back into cow feed), so more stringent regulations are needed.

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CATEGORIZED UNDER: Health & Medicine

Hundreds of Delicate Spirals on Martian Surface Indicate a Volcanic Past

By Veronique Greenwood | April 30, 2012 9:38 am

spacing is important

The HiRISE camera orbiting Mars spotted 269 of these beautiful coils on the surface of the Athabasca Valles Region of the Red Planet. The patterns, which range from 15 to more than 90 feet wide, seem to be larger versions of those sometimes observed on Earth after a volcanic eruption; they can arise when two lava flows going in opposite directions curl around each other, or when the molten lava rotates slowly because of differences in the density or viscosity of two intersecting flows. There has been debate among scientists over whether the region’s unusually patterned surface was formed by ice or lava, and the publication of these images in this week’s Science adds credence to the lava theory.

Image courtesy of NASA/JPL/University of Arizona


The Real Problem with Driverless Cars

By Veronique Greenwood | April 28, 2012 8:08 am

When Nevada made driverless cars legal in the state last year, we armchair futurists sat up a little straighter. All of a sudden a number of meandering philosophical questions about how our society would have to change to embrace such technology seemed quite a bit more urgent. This question seemed especially pressing: Driverless cars are safer than those piloted by humans, but how would we feel about deaths caused by machines rather than people?

In our post on the topic we considered the ethics of the situation, but we think this recent short piece from Popular Science nails the liability angle on the issue: the real question, as far as car manufacturers are concerned, is not whether the cars are fundamentally safer, but who will should take legal responsibility for the accidents:

When a company sells a car that truly drives itself, the responsibility will fall on its maker. “It’s accepted in our world that there will be a shift,” says Bryant Walker Smith, a legal fellow at Stanford University’s law school and engineering school who studies autonomous-vehicle law. “If there’s not a driver, there can’t be driver negligence. The result is a greater share of liability moving to manufacturers.”

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Want to Make Rational Decisions? Think About Them In a Foreign Language.

By Sarah Zhang | April 26, 2012 12:48 pm

spacing is important

Behavioral economists have documented the all too many ways that humans are predictably irrational. Emotions and biases often just get the better of us. In a new study in Psychological Science, however, psychologists found that people forced to think in a foreign language made more rational decisions. C’est vrai!

Psychologists took classic scenarios from behavioral economics and posed them to students in their native and foreign languages. Here’s an example of one:

There’s a disease epidemic sweeping through the country, and without medicine, 600,000 people will die. You have to choose one of two medicines to make:

If you choose medicine A, 200,000 people will be saved. If you choose medicine B, there is a 1/3 chance of saving 600,000 people and a 2/3 of saving no one. Which medicine do you choose?

Most people would go with A, the less risky bet, because we’re risk-averse when the choice is framed as a gain—as in “saving people.” But what if we framed the question a little differently in this second scenario?

If you choose medicine A, 400,000 people will die. If you choose medicine B, there is a 1/3 chance of saving 600,000 people and a 2/3 of saving no one. Which medicine do you choose?

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CATEGORIZED UNDER: Mind & Brain, Top Posts

Ancient Microbes ("Bacteriasicles") From Melting Glaciers Are Spilling Into Oceans

By Sarah Zhang | April 26, 2012 11:47 am

spacing is important

Melting polar ice has a worrisome list of consequences—methane gas release, rising sea levels, and the liberation of long frozen 750,000-year-old microbes. While melting glaciers probably aren’t going to turn into Jurassic Park, scientists are understandably concerned how they might affect the environment. Scientific American has a new feature on the impact of these liberated microbes on ocean life:

More likely is [the] prospect that thawing ice sheets will allow ancient microbial genes to mix with modern ones, flooding the oceans with never-before-seen types of organisms. Rogers [an evolutionary biology] believes this is already taking place. “What we think is happening is that things are melting out all the time and you’re getting mixing of these old and new genotypes,” he said.

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Early Skeleton Stolen From Underwater Cave in Mexico

By Veronique Greenwood | April 26, 2012 11:47 am

The interior of a cenote

The cenotes of the Mexican state of Quintana Roo are peppered with mysterious skeletons. Over the millennia, these water-filled caves have served as burying grounds and sacrificial sites for native peoples, and in fact, several ancient sets of remains have been found so deep in the caves that they are inaccessible without diving equipment, suggesting that they must have been placed there when the caves were dry, before the ice caps melted around 8,ooo BCE, and putting them in the range of 10-14,000 years old.

Now, though, one of those ancient skeletons, called the Young Man of Chan Hol II since its discovery in 2010, has gone missing from its cenote. New Scientist reports that the National Institute of Anthropology and History has put up posters in bakeries, supermarkets, and divers’ shops throughout the town of Tulum in hopes of receiving tips as to the skeleton’s whereabouts and is considering legal action, though we’re not sure what actions are possible against thieves. Apparently there have been other archaeological thefts from cenotes as well; the cenotes are frequented by divers, and the authorities cannot guard them all.

Image courtesy of Darren Fry / flickr



New Study That Allegedly Found the Fabled G-Spot Is Deeply Flawed

By Veronique Greenwood | April 25, 2012 12:54 pm


You may have heard the G-spot buzz today: a gynecological surgeon claims to have discovered an actual structure in a vagina that corresponds to this reputed female pleasure center. Just by itself, any invocation of the G-spot should set off alarms; it has been called a “gynecologic UFO: much searched for, much discussed, but unverified by objective means.”

There is much about this particular study, though, that is deeply troubling, as best exposed by Ricki Lewis, who has authored textbooks on human physiology, at Scientific American. Here is a quick sum-up of what is so wrong about this situation.

Big Problem #1

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CATEGORIZED UNDER: Health & Medicine

Blood in Leeches Alerts Scientists to the Presence of Hard-to-Spot Endangered Animals

By Veronique Greenwood | April 24, 2012 12:21 pm

The scientists’ blood-sucking accomplices

What’s the News: Scientists searching for new and endangered species in tropical highlands face a Catch 22. Spotting shy creatures is the order of the day, but bushwhacking through forests is anything but subtle. How can you get a sense of what’s there when you can’t get close enough to see it?

Environmental DNA analysis is one of the answers—checking out the DNA in soil, for instance, can reveal what pooped there recently in amazing detail. But for a technique that can reach beyond a given patch of ground, scientists have been investigating using leeches from streamwater as their source of DNA. It turns out that blood from their last meal sticks around in their gut for a good long time, and they happen to be partial to human blood too—which makes them, in the scientists’ words, “easy to collect.” A new paper gives proof that the technique is valuable: blood in leeches collected from a Vietnamese rainforest reveals the presence of six mammalian species, some of them rare.

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CATEGORIZED UNDER: Living World, Top Posts

In the Philippines, A Bright Purple New Crab Species

By Sarah Zhang | April 24, 2012 12:07 pm

spacing is important

In the 1980s, scientists identified a crab species in the Philippines and gave it the delightful of name of Insulamon unicorn. Twenty years later, scientists have found some of its cousins (pdf): four new freshwater crab species in the same genus. This purple one with red-tipped claws is I. palawanese. 

Isolated on the island, the Insulamon have evolved to live in freshwater rather than seawater, hiding out under roots and rocks near stream beds. This little guy is remarkably colorful and easy to spot, despite being less than two inches across.

[via Discovery News]

Image via Hendrik Freitag / Senckenberg Museum of Comparative Zoology


Computers Can Grade Essays As Well As People Can

By Veronique Greenwood | April 23, 2012 1:49 pm

RS is the average of scores given by two human readers;
all the others are computer programs.

To anyone who’s ever written an essay for a standardized test—be it the SAT, the ACT, the GMAT, or others—it should come as no surprise that getting a high-scoring essay is a matter of following a formula. The SAT is not the time to show off your lyrical ability or demonstrate your awareness of the nuances of morality: when the prompt is “Is it better to have loved and lost than never loved at all?” it’s hard to argue “It depends” in 25 minutes. Just take a stance, come up with two supporting examples, and hammer that baby out.

Turns out, though, that standardized test essays are so formulaic that test-scoring companies can use algorithms to grade them. And before you get worried about machines giving you a bad score because they’ve never taken an English class, said algorithms give the essays the same scores as human graders do, according to a large study that compared nine such programs with humans readers. The team used more than 20,000 essays on eight prompts, and you can see in the figure to the right, the mean scores found by the programs and the people were so close that they appear as one line on a chart of the results.

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