Science & TechnologyS


Footprints

New Technique Uses Genomes To Determine Ancient Human Migrations

Migration Studies
© redOrbit

Researchers at Cornell University have developed new statistical methods based on the complete genome sequences of living humans to shed light on events at the dawn of human history.

The scientists applied their methods to the genomes of individuals of East Asian, European, and western and southern African descent.

Although they analyzed just six genomes, the researchers made use of the fact that these genomes contain traces of genetic material from thousands of human ancestors, which have been assembled into new combinations over the millennia by genetic recombination.

The primary finding of the study is that the San, an indigenous group of hunter gatherers from southern Africa, diverged from other human populations about 130,000 years ago - earlier than previously thought. By comparison, the ancestors of modern Eurasian populations migrated from Africa only about 50,000 years ago.

Previous studies of human demography have primarily relied on mitochondrial DNA from the maternal line or Y-chromosome data passed from fathers to their sons. However, those studies were limited by small numbers of genomic positions.

The current study uses the full genome of each individual, providing a more comprehensive view of human evolution, the researchers said.

"The use of genomewide data gives you much more confidence that you are getting the right answer," said Adam Siepel, associate professor of biological statistics and computational biology, and senior author of the paper.

Info

Now Showing: Movie Clips From Your Mind

Mind Movies
© Jack GallantStudy subjects were shown movie trailers (left), and neuroscientists were able to reconstruct them (right) using brain activity data and a library of random YouTube clips.

What if scientists could peer inside your brain and then reconstruct what you were thinking, playing the images back like a video?

Science and technology are not even remotely at that point yet, but a new study from the University of California Berkeley marks a significant, if blurry, step in that direction.

"Using our particular modeling framework, we can actually infer very fast dynamic events that happen in the brain," said Jack Gallant, a neuroscience professor at the University of California Berkeley who worked on the study, which was published today in the journal Current Biology.

To try and read the brain, the scientists had people watch compilations of clips from Hollywood movie trailers while staying still inside a functional Magnetic Resonance Imaging machine, better known as fMRI. The machine took scans as the subjects watched the compilation 10 times, totaling around two hours.

Saturn

A Quintet of Saturn's Moons

A quintet of Saturn's moons come together in the Cassini spacecraft's field of view for this portrait.

Image
© NASA/JPL-Caltech/Space Science Institute
Janus (179 kilometers, or 111 miles across) is on the far left. Pandora (81 kilometers, or 50 miles across) orbits between the A ring and the thin F ring near the middle of the image. Brightly reflective Enceladus (504 kilometers, or 313 miles across) appears above the center of the image. Saturn's second largest moon, Rhea (1,528 kilometers, or 949 miles across), is bisected by the right edge of the image. The smaller moon Mimas (396 kilometers, or 246 miles across) can be seen beyond Rhea also on the right side of the image.

This view looks toward the northern, sunlit side of the rings from just above the ringplane. Rhea is closest to Cassini here. The rings are beyond Rhea and Mimas. Enceladus is beyond the rings.

Roses

A Plant That Sows Its Own Seeds Discovered

Image
© Alex PopovkinSpigelia genuflexa
Scientists have discovered a tiny plant which they say bows down and sows its own seeds.

The dainty, inch-high plant with pink-and-white flowers was found growing in the backyard of a local plant collector in rural northeastern Bahia, Brazil, one of the world's most biologically diverse areas.

The strange behaviour of the plant caught the attention of a handyman working for the plant collector, Alex Popovkin, who believed it was a new species.

A team of scientists from Rutgers University, the State University at Feira de Santana in Bahia, and Western Carolina University then collaborated to confirm that the plant was indeed a new species, a website reported.

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New Space Woe: Blurry Vision

Blindess In Space
© NASAAbout one-third of the U.S. space station crewmembers return with impaired vision, a condition in which at least one case was permanent.
A new study of astronauts shows that radiation and bone loss aren't the only health risks for long-duration stays in space. About one-third of the U.S. space station crew members return with impaired vision, a condition in which at least one case was permanent.

The data has been slow in coming since astronauts can be disqualified from flying if they have serious ailments.

"These are guys who really don't like to complain about physical issues because it may ground them. They're desire is to get back into space, so they are not complainers," neurosurgeon Bruce Ehni at Baylor College of Medicine in Houston, told Discovery News.

But in 2005, one unnamed astronaut came forward to reveal his affliction, prompting a survey of the corps. NASA discovered 35 percent of its former space station crew members, who typically spend about six months in orbit, experience visual acuity issues, agency spokesman Mike Curie told Discovery News.

Info

Belief in God Boils Down to a Gut Feeling

Child Praying
© Live Science

For many people, believing in God comes down to a gut feeling that a benevolent deity is out there. A study now finds that gut feelings may be very important in determining who goes to church every Sunday and who avoids the pews.

People who are generally more intuitive in the way they think and make decisions are more likely to believe in God than those who ruminate over their choices, the researchers found. The findings suggest that basic differences in thinking style can influence religious belief.

"Some say we believe in God because our intuitions about how and why things happen lead us to see a divine purpose behind ordinary events that don't have obvious human causes," study researcher Amitai Shenhav of Harvard University said in a statement. "This led us to ask whether the strength of an individual's beliefs is influenced by how much they trust their natural intuitions versus stopping to reflect on those first instincts."

Bulb

Can't stop yawning? You might not just be tired... your brain could be over-heating

We most associate yawning with boredom or being sleepy, but new research suggests it can be good for your health - by cooling down your brain.

Scientists at Princeton University found a big yawn can regulate the temperature of the brain and prevent over-heating.

Baby Yawning
© AlamyStrange as it seems we yawn more in winter to keep the brain cool, according to scientists.
During winter in Tuscon, Arizona, Professor Andrew Gallup and his team asked 80 random pedestrians to look at images of people yawning and then recorded whether they yawned in response.

They then performed the same trial in the summer.

The researchers found that half of the participants yawned in winter while only a quarter yawned in summer.

Health

What's In That Wine Glass May Not Prevent Aging After All

Red Wine
© iStockphotoRed wine's rep as a fountain of youth is facing a challenge.

If you've been counting on your daily dose of merlot to stave off mortality, you might want to consider Plan B.

The links between red wine and longevity aren't nearly as strong as they once seemed, according to new research in the journal Nature. In fact, the research calls into question the whole mechanism used to explain wine's power to extend life.

Sorry, oenophiles.

This all has to do with some natural proteins called sirtuins. (That's pronounced sir-TWO-ins in American English, in case you're reading this out loud at a bar.) Yeast carry a version. So do worms, mice and people.

About 10 years ago, scientists noticed that an extra helping of sirtuins seemed to help living things live longer. And there was some evidence that a substance in red wine called resveratrol could crank up sirtuin production.

Then, in 2006, a Harvard researcher named David Sinclair reported that obese mice that got doses of resveratrol lived longer than fat mice who didn't - about 30 percent longer.

Beaker

Pint-Sized Accelerator Creates the Mother of All Gamma Rays

Thin layers of lead won't stop these bad boys
Image
© University of StrathclydeResearch assistant Silvia Cipiccia holds the laser accelerator's waveguide in hand. The high tech laser allowed the creation of ultra-intense gamma rays, which are expected to have diverse applications.

Gamma rays -- they're what made the fictional Hulk, and they are today saving lives via medical imaging and radiation therapy for cancers, not to mention unlocking the mysteries of the universe. But many of these applications are confined by how powerful (intense) these beams are. Thus these applications may get a huge boost from research by the University of Glasgow and University of Strathclyde (located in Glasgow, Scotland, UK), along with Instituto Superior Técnico (Lisbon, Portugal) which has produced the most intense gamma rays man has ever been able to produce.

The super rays are a thousand times brighter than the Sun. And they are so intense they can penetrate up to 20 cm (over half a foot) of lead, or 1.5m (almost 5 feet) of concrete.

The peak radiance of the super-bright beam was more than 10e23 photons per second, per square milliradian, per square millimeter, per 0.1% bandwidth. If you're not involved in research physics, suffice to say that's a whole lot of high-energy photons.

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Fight or Flight: How the Nose Knows What to Do

Sensory Detection Cells
© Yoh Isogai and Catherine DulacThis image illustrates the cellular diversity underlying sensory detection in the mouse vomeronasal organ. A spectrum of colors highlights sensory neurons harboring different receptors, each recognizing a different set of social or predator cues.

Cats arch their backs at the smell of a rival, and mice scurry at the scent of a fox. But how does the nose know who or what is lurking? Now scientists have identified several special receptors in the noses of animals that react to specific scents given off by others.

It's these receptors that signal to the brain whether the animal needs to flee, make itself large and scary, or perhaps even woo a mate.

"Animals in the wild need to be able to recognize other animals, whether they are predators, potential mates or rivals," study researcher Catherine Dulac of Harvard University told LiveScience. "Many animals rely on the sense of smell; they can distinguish one type of encounter from another one based on chemicals."

Experimenting on mice, Dulac and her fellow researchers discovered that more of the animal's receptors seem to be dedicated to sniffing out predators than to detecting potential mates.