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Tue, 09 Feb 2016
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Bulb

Babies can see things that adults cannot

© Catherine DELAHAYE/Photononstop/Corbis)
When babies are just three to four months old, they can pick out image differences that adults never notice. But after the age of five months, the infants lose their super-sight abilities, reports Susana Martinez-Conde for Scientific American.

Don't get too jealous of the superior discrimination that infants have however: The reason adults—or even babies older than about eight months—don't have it is because overtime, our brains learn what differences are important to notice.

Blue Planet

Why a walk in the woods really does help your body and your soul

© Shutterstock/Stokkete
There’s something in the tree air and it’s good for you.
Have you ever wondered why you feel healthier and happier when you stroll through the trees or frolic by the sea? Is it just that you're spending time away from work, de-stressing and taking in the view? Or is there more to it?

For more than 20 years, scientists have been trying to determine the mechanisms by which exposure to biodiversity improves health. Japanese scientists pioneered the search when they travelled to the island of Yakushima, famous for its biodiversity.

The Japanese already had a name for the experience of well-being in nature: shinrin-yoku or "forest bathing".

Info

New technology lets scientists locate underwater landslide that triggered deadly 1964 Alaskan tsunami

© U.S. Geological Survey
In the photo above, a section of Kodiak, Alaska, is in ruins after the massive tsunami that followed the Great Alaska Earthquake in March 1964.
Five decades after the nation's most powerful earthquake hit Alaska, scientists have pinpointed the underwater slide that triggered some of the deadliest tsunami waves produced by the shaking.

Using modern technology to map the floor of Prince William Sound, scientists from the U.S. Geological Survey and other organizations have found the landslide behind the tsunamis that killed about a third of the people in the Alutiiq village of Chenega, the service said on Monday.

Twenty-three of the village's 75 residents perished within minutes of the magnitude-9.2 earthquake that struck in 1964, making Chenega one of the communities hardest hit by the event. The village was nearly leveled and later rebuilt at a different site with a slightly different name, Chenega Bay.

In the immediate aftermath of the earthquake, scientists speculated that underwater landslides produced the waves that struck Chenega, the USGS said. A USGS technical report on the earthquake that was published in 1969 cited "localized waves of unknown origin" as the source of the most destruction. "The local waves, and combinations of local waves and subaqueous slides, caused most of the earthquake related fatalities in Alaska," that report said.

But the bathymetric technology of the time allowed for study of the seafloor only to the depth of about 180 meters, or 330 feet, the USGS said. Modern surveys conducted with multibeam sonar technology and a seismic-reflection system revealed a big complex of underwater slides that had occurred at much lower depths, the USGS said.

The findings of the USGS-led project are described in a study published online in the journal Earth and Planetary Science Letters.

"What makes this slide unusual is that much of the material that slid was at a water depth of 250 to 350 meters," or 820 to 1150 feet, Peter Haeussler, a USGS geologist based in Anchorage and a co-author of the study, said in a statement released by the survey. "The deeper initiation depth made it particularly good at generating a tsunami."

Comment: Remembering the great Alaskan earthquake and tsunami: Alaska, March 1964


Fireball 2

Close call? Asteroid could pass Earth by 11k miles, 95% closer than the moon

© DLR German Aerospace Center / Wikipedia
A recently discovered asteroid is scheduled to fly by Earth in March, but NASA can't quite tell how far away it will be when that happens. One estimate is as close as 11,000 miles, about 95 percent closer than the moon.

The asteroid known as 2013 TX68, was first discovered three years ago, as its name implies, but the NASA-funded Catalina Sky Survey was only able to track its path for three days before it entered daytime skies, where monitoring is not possible. That short amount of time precluded scientists from getting a better understanding of what the asteroid's orbit around the sun looks like.

What is known is that the asteroid is 100 feet (30 meters) in diameter and will be in Earth's neighborhood for quite some time, but what is not known is whether that means 11,000 or 9 million miles away from our planet by next month. For comparison, the moon is 238,000 miles away.

"This asteroid's orbit is quite uncertain, and it will be hard to predict where to look for it," Paul Chodas of NASA's Center for Near Earth Object Studies said in a statement.

"There is a chance that the asteroid will be picked up by our asteroid search telescopes when it safely flies past us next month, providing us with data to more precisely define its orbit around the sun," Chodas added.

Comment: We are special, so nothing to worry about!


Bullseye

So long, bloodsuckers: Scientists crack bedbug genetics, plan its annihilation

© Wikipedia
Bedbugs be gone! Scientists have successfully cracked the genetic makeup of the blood-sucking parasites, which could lead to their eventual annihilation.

Okay, complete eradication is perhaps wishful thinking. But researchers at the American Museum of Natural History and Weill Cornell Medicine are hoping a genome breakthrough will lead to more effective ways to battle the sleep-destroying pest.

By getting a handle on what makes the little ticks, erm ... tick, scientists may now be able to tailor pesticides to kill the ever-mutating creepy crawlies.

Comment: See also: Pesticide resistance: Widely used chemicals no longer effective against bedbugs


2 + 2 = 4

Cells talk to their neighbors before making a move

Comparing notes boosts cells sensing accuracy

© sakkmesterke / Fotolia
Like the telephone game -- where a line of people whisper a message to the person next to them -- an original message starts to become distorted as it travels down the line between cells, report scientists.
To decide whether and where to move in the body, cells must read chemical signals in their environment. Individual cells do not act alone during this process, two new studies on mouse mammary tissue show. Instead, the cells make decisions collectively after exchanging information about the chemical messages they are receiving.

"Cells talk to nearby cells and compare notes before they make a move," says Ilya Nemenman, a theoretical biophysicist at Emory University and a co-author of both studies, published by the Proceedings of the National Academy of Sciences (PNAS). The co-authors also include scientists from Johns Hopkins, Yale and Purdue.

Boat

Standard ship noise causes interference with orca communication

© beamreach.org
Sharing the sound.
Ship noise may be making it harder for endangered orcas (Orcinus orca) that live in the coastal waters off Seattle, Washington, to catch salmon.

Known to scientists as Southern Resident Killer Whales, this population comprises the only known resident orcas in the United States. In the late 1800s, they numbered about 200. But their numbers crashed in the 1960s, after some 47 were captured for display. Today, there are about 80, and they are protected by the Endangered Species Act.

The whales already suffer from depleted stocks of Chinook salmon. Now, scientists report online today in PeerJ that commercial ships entering Haro Strait where the orcas live (as shown in the photo above), are likely interfering with the calls the whales make to communicate and locate prey.

For 28 months, from March 2011 to October 2013, the researchers used a hydrophone placed 50 meters offshore in the center of the orcas' summertime habitat to measure the noise from 1582 individual ships, including ore carriers, tugs, oil tankers, cargo, military, yachts, and fishing vessels. They found that ships are radiating underwater noise at high frequencies, 10,000 to 40,000 hertz—the same range that orcas and other toothed whales use.

Although the scientists do not yet know specifically how the ships' sounds are affecting the orcas, they note that other researchers have shown that the whales increase the amplitude of their most common calls when loud boats pass nearby. The study adds to global concerns about commercial ships' noise and whales' (including baleen whales, like blue whales) hearing. For instance, scientists have found that North Atlantic right whales have lower stress levels in areas without the sound of ships.

Quieting technology to limit ships' noise already exists, and is used by the military vessels, which are surprisingly silent, the scientists say. And, they note, there's potentially an even easier fix: Slow down.

Comment: See also: Shhh ... Ocean Noises Stress Out Whales


Bizarro Earth

Research: Dehydration of mineral lawsonite could trigger intermediate depth earthquakes in some subduction zones

© Hirth Lab / Brown University
The mineral lawsonite undergoes brittle failure at high temperature and pressure, as evidenced by the cracks seen in the sample above. That brittleness could trigger earthquakes in subduction zones where lawsonite is present.
Geologists from Brown University may have finally explained what triggers certain earthquakes that occur deep beneath the Earth's surface in subduction zones, regions where one tectonic plate slides beneath another.

Subduction zones are some of the most seismically active areas on earth. Earthquakes in these spots that occur close to the surface can be devastating, like the one that struck Japan in 2011 triggering the Fukushima nuclear disaster. But quakes also occur commonly in the subducting crust as it pushes deep below the surface -- at depths between 70 and 300 kilometers. These quakes, known as intermediate depth earthquakes, tend to be less damaging, but can still rattle buildings.

Intermediate depth quakes have long been something of a mystery to geologists.

"They're enigmatic because the pressures are so high at that depth that the normal process of frictional sliding associated with earthquakes is inhibited," said Greg Hirth, professor of earth, environmental, and planetary sciences at Brown. "The forces required to get things to slip just aren't there."

Compass

Biological compass: Light receptor proteins are sensitive to the direction of geomagnetic fields

Many animals including birds and insects have been observed to perceive geomagnetic fields. Past studies have demonstrated that cryptochrome/photolyase family (CPF) light receptor proteins are involved in animal behavioral responses to the presence of geomagnetic fields, but so far, no studies have determined whether these proteins are linked with the direction of the magnetic field vector.

Recently, an international collaborative of researchers explored the possibility that CPF proteins provide directional magnetosensitivity in cockroaches. By combining behavioral and genetic approaches, they demonstrated the first evidence that animal-type cryptochrome (Cry2) proteins are sensitive to the direction of geomagnetic fields in two cockroach species. They've published their results in the Proceedings of the National Academy of Sciences.

Magnet

Earth's magnetic field history

© Peter Driscoll and David Evans
This figure illustrates superchrons of both normal and reversed polarity over time as the Earth's molten core formed and solidified. It is provided courtesy of Peter Driscoll and David Evans.
Earth's magnetic field is generated by the motion of liquid iron in the planet's core. This "geodynamo" occasionally reverses its polarity—the magnetic north and south poles swap places. The switch occurs over a few thousand years, and the time between reversals can vary from some tens of thousands to tens of millions of years.

When magnetic polarity remains stable in one orientation for more than 10 million years the interval is dubbed a "superchron." Within the last 540 million years—the time when animals have roamed the Earth's land and seas—there are three known superchron periods, occurring about once every 200 million years.

The question of how frequently reversals and superchrons occurred over a longer segment of Earth's history is important for understanding the long-term evolution of the internal and surface conditions of our planet. But so far, such information has only been pieced together by fragmentary evidence. New work from Carnegie's Peter Driscoll and David Evans of Yale University now identifies as many as 10 additional superchrons over a 1.3 billion-year stretch of time during the Proterozoic Eon, or Earth's middle age, which occurred 2.5 to 0.54 billion years ago. Their work is published in the March 1st issue of Earth and Planetary Science Letters.

Records of magnetic field reversals can be found in rocks that maintain the magnetic polarity of the era in which they formed. In order to establish evidence of a polarity shift, this kind of ancient magnetic, or "paleomagnetic," data must be gathered from around the globe, ideally sampling every tectonic plate.