Tag: PNAS

Musical Harmony May Be Hardwired in the Brain

By Lisa Raffensperger | November 16, 2012 1:34 pm

Man with parabolic ear attachments device Anyone who’s ever watched a horror film will know that the sound of two clashing notes evokes a visceral response in most people. Among Western listeners there’s a strong preference for consonance, which exists even from infancy; consonance is the pleasing mixture of two tones, while dissonance is their clashing. (For a good example of both, see this video.) It’s controversial whether the same preferences exist in other cultures, but new research indicates the preferences might be wired in our brains.

The prevailing theory of music in the brain is that dissonant combinations share frequencies that are a bit too close. When these frequencies are perceived by the cochlea, the part of the inner ear that translates sounds to nerve impulses, they can’t be well distinguished. Because similar frequencies are processed next to one another on the cochlea, their nerve signals can interfere with one another. The perception is a grating effect, called “beating.” Read More

CATEGORIZED UNDER: Mind & Brain
MORE ABOUT: audio, brain, harmony, hearing, music, PNAS

Study: Switch to Farming Shortened Jaws, Giving Us Crowded & Crooked Teeth

By Douglas Main | November 23, 2011 11:15 am

What’s the News: Parents going broke to pay for their offspring’s braces and orthodontistry can finally blame somebody besides their mildly malformed children: our farmer ancestors. A study published this week in the Proceedings of the National Academy of Sciences found that people living in subsistence farming communities around the world have shorter, wider jaws than those in hunting and gathering societies. This leaves less room for teeth, which have changed little in size or abundance over human history—and may help explain why crooked choppers and a need for orthodontia are so common, study author Noreen von Cramon-Taubadel tells the BBC. “I have had four of my pre-molars pulled and that is the only reason that my teeth fit in my mouth,” she says.

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CATEGORIZED UNDER: Environment, Human Origins, Top Posts

A Big Eruption in Iceland Could Kill Tens of Thousands in Europe, Model Predicts

By Veronique Greenwood | September 20, 2011 2:01 pm

laki
The Laki fissure’s eruption in Iceland was behind tens of thousands of deaths in the 1780s.

What’s the News: Iceland’s busy volcanoes have caused their share of air traffic snafus in Europe lately, but they have the potential to be deadly, not just inconvenient. A new model examining how air quality would change should the volcanoes erupt as spectacularly as they occasionally have in the past suggests that increased particulates in the air could kill more than 140,000 people in Europe in the year following the eruption.

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Is Culture Behind Men's Better Spatial Reasoning?

By Joseph Castro | August 30, 2011 4:12 pm

spacing is important

What’s the News: In the long-running debate over the differences between men and women, one mental skill has emerged as being perhaps more biologically rooted than any other: the ability to solve problems involving physical spaces, shapes, or forms. Many studies have concluded that men simply seem to have an inherent advantage in this area. But a new study of two tribes in Northern India is suggesting that the gender gap we see in spatial skills may be partially due to culture rather than raw biology. This finding may affect the way researchers look at gender differences, but it will surely not settle the question, considering that it’s one study of a small group of people living in one limited environment.

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CATEGORIZED UNDER: Mind & Brain
MORE ABOUT: math, mental math, PNAS, puzzle

Ancient Whales' Twisted Skulls Were Useful: They Helped Them Hear Better

By Joseph Castro | August 23, 2011 1:28 pm

spacing is importantThree-dimensional model of an ancient whale skull.

What’s the News: Scientists have long held that archaeocetes, the precursors to modern cetaceans, had symmetrical skulls like most other mammals. Whale skulls only became asymmetrical as certain species evolved echolocation to hunt for food. But it turns out that archaeocetes actually had skewed skulls, which likely allowed the whales to hear better underwater, according a new study published in the journal PNAS.

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CATEGORIZED UNDER: Living World

Eyes on the Radioactive Wind, Scientists in California Study the Fukushima Meltdown

By Veronique Greenwood | August 16, 2011 12:37 pm

fukushimaClean-up teams at Fukushima struggled to control the melting fuel rods.

What’s the News: After the disastrous March 11 earthquake and tsunami in Japan, the world waited, mostly in vain, for details about the events that led to meltdown at the Fukushima Daiichi nuclear plant. Since then, scientists across the Pacific in California have been watching the dials of instruments that detect radioactive molecules, to see what might come across on the winds.

This week, scientists at Scripps published their readings of radioactive sulfur collected in the atmosphere in San Diego after the meltdown. These allowed them to extrapolate backwards to learn roughly how many neutrons were shed by the melting cores as workers desperately doused them in sea water, helping scientists understand the damage undergone by the cores and demonstrating the kind of remote science that may be required to help understand the events that led to meltdown.

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CATEGORIZED UNDER: Physics & Math, Technology, Top Posts

Spinal Discs Grown From Cells Could Someday Repair Bad Backs

By Joseph Castro | August 3, 2011 4:04 pm

spacing is importantLeft: normal rat disc. Right: engineered disc.

What’s the News: Researchers at Cornell University have now bio-engineered synthetic spinal discs and implanted them in rats. The implants provide as much spinal cushioning as authentic discs do, and improve with age by growing new cells and binding to nearby vertebrae, according to the study recently published in the journal PNAS. The research could someday help people with chronic lower back and neck pain from conditions like degenerative disc disease.

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CATEGORIZED UNDER: Health & Medicine, Top Posts

Bacteria Use Limbs to Slingshot Themselves Across a Surface

By Veronique Greenwood | July 19, 2011 2:16 pm

pilus
Kaaa-pwing!

What’s the News: Bacteria are known for sprouting spindly limbs and pulling themselves along surfaces like miniature octopi. But a new study shows that by tacking down one limb, pulling it till it’s taut, and then letting go, bacteria can also use the limbs to slingshot themselves around.

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CATEGORIZED UNDER: Health & Medicine, Living World

Parallel Lines Never Cross, Even in Remote Amazonia

By Valerie Ross | May 24, 2011 3:20 pm

What’s the News: Adults and school-age children may understand some basic principles of geometry even without formal math training at all, according to a study published online yesterday by the Proceedings of the National Academy of Sciences. Thirty members of the Mundurucú, an indigenous Amazonian group, could intuitively grasp geometric concepts about angles, lines, and points, the researchers found.

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CATEGORIZED UNDER: Mind & Brain, Physics & Math

Promising New Mosquito-Repellent Molecule Overwhelms Bugs' Sense of Smell

By Veronique Greenwood | May 10, 2011 4:26 pm

mosquito

What’s the News: Forget masking our scent or making us taste bad—sensory overload might be our most potent tool in repelling mosquitoes. And we might someday have a repellent for the job: Scientists have just discovered a molecule that zaps all of a mosquito’s odor receptors at once, overwhelming it. The molecule’s not ready to be deployed yet, but early tests indicate it could be thousands of times more effective than DEET.

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CATEGORIZED UNDER: Health & Medicine, Living World
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