Jun 23, 2012

Stonehenge Built as Symbol of Unity

Stonehenge was built as a monument to unify the peoples of Britain, researchers have concluded after 10 years of archaeological investigations.

Dismissing all previous theories, scientists working on the Stonehenge Riverside Project (SRP) believe the enigmatic stone circle was built as a grand act of union after a long period of conflict between east and west Britain.

Coming from southern England and from west Wales, the stones may have been used to represent the ancestors of some of Britain's earliest farming communities.

According study leader Mike Parker Pearson of the University of Sheffield, Britain's Neolithic people became increasingly unified during the monument's main construction around 3000 B.C. to 2500 B.C.

"There was a growing island-wide culture -- the same styles of houses, pottery and other material forms were used from Orkney to the south coast," Parker Pearson said.

"Stonehenge itself was a massive undertaking, requiring the labour of thousands to move stones from as far away as west Wales, shaping them and erecting them. Just the work itself, requiring everyone literally to pull together, would have been an act of unification," Parker Pearson said.

According to the researcher, who has detailed the new theory in the book Stonehenge: Exploring the Greatest Stone Age Mystery, the place in the county of Wiltshire where the iconic stones were erected was not chosen by chance.

On the contrary, it already had special significance for prehistoric Britons.

Parker Pearson and colleagues noticed that Stonehenge's solstice-aligned avenue sits upon a series of natural landforms which mark out the midsummer sunrise and midwinter sunset.

"When we stumbled across this extraordinary natural arrangement of the sun’s path being marked in the land, we realized that prehistoric people selected this place to build Stonehenge because of its pre-ordained significance," Parker Pearson said.

Basically, they would have seen the spot as nothing less than the "center of the world."

"This might explain why there are eight monuments in the Stonehenge area with solstitial alignments, a number unmatched anywhere else,” Parker Pearson said.

According to the researchers, the winter solstice was the more significant time of the year when Stonehenge was built 5,000-4,500 years ago.

"We can tell from ageing of the pig teeth that higher quantities of pork were eaten during midwinter at the nearby settlement of Durrington Walls, and most of the monuments in the Stonehenge area are aligned on sunrise and sunset at midwinter rather than midsummer," said Pearson.

The prehistoric monument has long baffled archaeologists, who have argued for decades over its original purpose, with two main theories taking shape in recent years: one was that it was a healing space, the other that it was a place of the dead.

Read more at Discovery News

Feds Take Disputed Dino Fossils into Custody

Federal agents took possession of a dinosaur skeleton that is the subject of an ownership dispute on Friday afternoon, loading crates of fossilized bones into the back of a white truck from a storage building here in Sunnyside, Queens.

Homeland Security Investigations was taking the fossils to an undisclosed location for safekeeping until a federal case filed by the U.S. Attorney is resolved, Deputy Special Agent In Charge Glenn Sorge told reporters.

The fossils, which belong to a type of tyrannosaur called a Tarbosaurus, were sold at auction on May 20 on the condition of court approval. Mongolian officials and paleontologists say the 75-percent complete skeleton, which garnered a $1.1 million bid at the auction, was taken illegally from that country.

Since the auction, the auction house in charge of the sale, Heritage Auctions, has stored the Tarbosaurus bataar in a Cadogan Tate Fine Art facility in Sunnyside.

The U.S. Attorney for the Southern District of New York has sued to take possession of the dinosaur with the intent of returning it to Mongolia. On Tuesday (June 19), a federal judge signed a warrant allowing federal agents to seize the fossils while the legal case continues.

"Once that ownership is determined, we are confident that very quickly this dinosaur will be back in Mongolia," said Robert Painter, attorney for Mongolian President Mongolian President Elbegdorj Tsakhia.

Now that the dinosaur is in federal custody, the case can proceed in two ways, he said. If anyone else comes forward and makes a claim of ownership to the fossils, then the case would be litigated. If no one does so, then the U.S. government can move for a default judgment, which would give it ownership. If this latter scenario plays out, Painter said the Tarbosaurus could go back to Mongolia this year.

"This is very happy news for the paleontological community, not only Mongolian paleontology, it's the whole international paleontology community, because this really shows the paleontologists government cares (about) this thing and acknowledges this is part of history, acknowledges this is the culture heritage," said Bolorsetseg Minjin, a Mongolian paleontologist.

The U.S. attorney's bid to seize the fossils hinges on the argument that false statements appeared on customs forms accompanying the dinosaur when it entered the United States, as well as a claim that those importing the fossils knew they were stolen. The complaint filed with the court names the commercial fossil dealer Eric Prokopi as the person who received the fossils.

NEWS: Oldest Bird Was Actually a Dinosaur

In a statement issued to the media, Prokopi denied paleontologists' assertion the fossils must have been excavated in Mongolia, and said he had made no false statements.

"It's been claimed that I misrepresented what was being imported and did not properly declare its value. I can wholeheartedly say the import documents are not fraudulent, a truth I am confident will be brought to light in the coming weeks," Prokopi wrote.

Read more at Discovery News

Jun 21, 2012

Pandemic? How Mutant Bird Flu Goes Airborne

Half a year after controversy arose over research that created more transmissible forms of the bird flu virus, the second and final study to do so has been published. The publication describes how the H5N1 virus, with a handful of genetic changes, can become capable of airborne transmission — a prerequisite for a global flu pandemic.

"It's our hope that tomorrow's publication will help to make the world safer, particularly by stimulating many more scientists and policymakers to focus on preparing defenses," Bruce Alberts, editor-in-chief of the journal Science, where the most recent H5N1 study appears, said during a press conference Wednesday (June 20).

This study, conducted in Ron Fouchier’s lab at the Erasmus Medical Center in the Netherlands, found that as few as five mutations in the H5N1 virus were sufficient to enable it to spread via airborne droplets between ferrets, the mammalian stand-in for humans. Independently, another project accomplished the same thing, but used a different technique to create the mutant virus.

Both projects were intended to understand how H5N1 might acquire the ability to start a pandemic among humans. (H5N1 has devastated poultry around the world, but only rarely infects humans. When it does infect humans, the virus cannot spread effectively among them.)

In December, the U.S. National Science Advisory Board for Biosecurity (NSABB) requested that details of the studies be withheld to prevent them from falling into the wrong hands. This request ignited concerns about scientific censorship.

Some details of the study conducted in Fouchier's lab at Erasmus Medical Center had already been made public when the controversy erupted. However, the publication of the full study this week reveals the mutant H5N1 viruses created by this research were not as deadly as was widely reported. In fact, the researchers report, the infection did not kill any of the ferrets that contracted the disease through airborne droplets.

It was only when the researchers introduced massive doses of the virus directly into the animals' bodies, in particular by putting massive doses into their tracheae, that the infection killed. However, "inoculations at such high doses do not represent the natural route of infection," write the researchers.

According to the World Health Organization, nearly 60 percent of human H5N1 cases have been fatal. However, some researchers have said this statistic is misleading, because only people sick enough to see a doctor and receive a lab test are included in the overall tally of about 600 cases.

Pandemic potential?

To figure out how H5N1 might start a pandemic by acquiring the ability to pass between people via airborne droplets, Fouchier and his colleagues first looked to the past, specifically the flu pandemics of 1918, 1957 and 1968.

The researchers introduced three key mutations associated with pandemics into H5N1. This, however, was not enough to enable the virus to spread via airborne droplets. So, the researchers let nature take over, infecting ferrets with viruses taken from other infected ferrets. After 10 cycles, or serial passages, they found that the infection could spread via airflow from an infected ferret to a healthy one housed in cage nearby.

The ferrets that contracted the altered H5N1 viruses this way showed symptoms, including lethargy and lost appetites, but none died during the experiment, the researchers write.

They also found the new H5N1 viruses did not transmit as efficiently as the pandemic H1N1 "swine flu" virus that was responsible for a global pandemic in 2009.

To figure out what made the altered H5N1 virus capable of air travel, the researchers sequenced the genetic code of all of the viruses capable of spreading this way and found the three original mutations plus two additional changes shared by all of them.

"We show that as little asfive mutations, but certainly less than 10, are sufficient to make H5N1 virus airborne," Fouchier said during the press conference.

Studying influenza in ferrets is not the same as studying it in humans. However, influenza viruses in ferrets cause a disease similar to human flu, and ferrets are considered the best models in which to study influenza viruses, Fouchier said.

More than one way to make airborne H5N1

The other H5N1 study, conducted by Yoshihiro Kawaoka, a professor of virology at the University of Wisconsin-Madison, was published in the journal Nature in May.

Kawaoka's team took a different approach to the same end. They made an airborne version of the virus by introducing four mutations into its hemagglutinin protein (represented by the H in H5N1) and using that to create a hybrid with the pandemic "swine flu" virus, H1N1. Ferrets infected by airborne droplets carrying the virus did not die in this experiment, either.

Preliminary word of these research projects stoked fear that details on how to create these altered H5N1 viruses could fall into the hands of terrorists or inept laboratories, resulting in the release of a deadly virus that could spread around the globe.

Read more at Discovery News

Secret to Cheetahs' Speedy Stride Found

Cheetahs and greyhounds have very similar running styles, but somehow the big cats leave their doggy rivals in the dust.  Their secret: Cheetahs "switch gears" while running, striding more frequently at higher speeds, new research finds.

Greyhounds, on the other hand, seem to take the same number of strides per second at every speed.

Cheetahs have been recorded running at up to 65 mph (105 kilometers per hour) -- much faster than a greyhound, which, as the fastest canid (dog-like animal), is known to reach 43 mph (68 kph).

"Cheetahs and greyhounds are known to use a rotary gallop, and physically they are remarkably similar, yet there is this bewitching difference in maximum speed of almost a factor of 2," study researcher Alan Wilson, from the Royal Veterinary College in the United Kingdom, said in a statement.

Running wild

The researchers studied cheetahs from the ZSL Whipsnade Zoo in the suburbs of London and the Ann van Dyk Cheetah Centre in South Africa. They also studied retired racing greyhounds from the United Kingdom.

They planted force-measuring plates in the ground and had the animals chase after a piece of chicken. They took high-speed video of the animals in motion and measured the force created by the running animal, calibrated with how much it weighed.

The cheetahs being studied didn't come close to the speeds reported for wild cheetahs — the zoo animals reached 38 mph (61 kph), while the greyhounds topped out at 43 mph (68 kph).

The researchers said this was probably because the captive-born cheetahs have never really gotten the chance to let loose in the wild and run full throttle.

"They have lived in a zoo for several generations and have never had to run to catch food. They have probably never learned to run, particularly," Wilson said. "The next stage is to try to make measurements in wild cheetahs in the hope of seeing higher speeds."

Strut & stride

The researchers did find a few differences, however; for instance, the cheetah's stride was slightly longer than the greyhound's.

The captive cheetahs also were able to change their stride frequency (strides per second) as they reached higher speeds: At 20 mph (32 kph), they took 2.4 strides per second, but at 38 mph (61 kph), they took 3.2 strides per second. The greyhounds, on the other hand, maintained a constant rate of around 3.5 strides per second no matter how fast they ran.

Read more at Discovery News

Exoplanet 'Odd Couple' Defy Formation Theories

The two planets circling Kepler-36, a sun-like star in its senior years, are as different as Earth and Neptune. But unlike the hundreds of millions of miles that separate our solar system's rocky worlds from its gas giants, Kepler-36's brood come as close as 1.2 million miles (1.9 million kilometers, or 0.01 AU) from one another -- about five times the distance between Earth and the moon.

"When they're at their closest, it presents a spectacular view in the sky," astronomer Josh Carter, with the Harvard-Smithsonian Center for Astrophysics, told Discovery News.

The planet nearest to the parent star, designated Kepler-36b, is a solid body roughly 1.5 times the size of Earth, but more than four times heavier.

Its fraternal twin, Kepler-36c, is three times larger and twice as heavy. But the outer planet is shrouded in gas, similar to Neptune. Its little sister either lost its atmosphere or never had one.

Both scenarios are puzzling.

In our solar system, the division of rocky bodies inward and gas giants beyond is believed to be the result of temperature differences in the original disk of gas and dust from which the sun and planets formed.

The discovery of so-called "hot Jupiters" -- gas planets that circle very close to their parent stars -- spurred new theories that planets migrate into different orbits after they are born.

Systems like Kepler-36, however, will prompt scientists to fine-tune planet-formation theories, Carter said.

"These two planets are quite different. There's only a 10 percent difference in their distance (to the parent star), but their densities differ by a factor of eight," Carter said.

"I think it's very exciting," added astronomer Andrew Youdin, also with the Harvard-Smithsonian Center for Astrophysics. "It raises all kinds of questions about how planets get their atmosphere. Maybe one didn't get much and another further out did. Maybe one formed quicker.

The Kepler-36 discovery is a good example about how scientists piece together individual details to form a bigger picture of what is going on, said Steve Howell, deputy project scientist with NASA's Kepler space telescope.

Read more at Discovery News

Extreme Microbes Found Near Mummy Burial Site

About 500 years ago a group of Incas marched hundreds of miles through the treacherous Andes Mountains to the top of a distant volcano, where they buried three children alive as part of a religious ceremony. In 1999, an expedition led by explorer Johan Reinhard unearthed the mummies atop Argentina's Mount Llullaillaco (yoo-yay-YAH-co), finding that they were among the best preserved mummies ever discovered, with largely unscathed skin and facial features.

When University of Colorado researcher Steve Schmidt read about the mummies, he knew he had to visit the region — not to see the mummies, but to study microbes. Normally, bodies that old would have long ago decayed, in part by the action of microbes, so Schmidt reasoned that the microbes on the mountain, if there were any, must be pretty intriguing.

"Finding a body so well-preserved 500 years after burial, without preservatives — that's remarkable," Schmidt told OurAmazingPlanet. "That's the reason I first got interested in the mountain."

Mountain microbes

So his team traveled to the area, climbed the volcano and took samples of soil near the summit. After performing genetic tests on the microbes, his group found several unique varieties that have not been described before. The most abundant were from a subset of Actinobacteria, the group that has given rise to most human antibiotics. They also came from 12 different broad groups called phyla, and all three domains of life.

And yet, the lack of diversity was what most surprised Schmidt. "We've studied many other soils around the world, and this is by far the simplest system we've seen," Schmidt said. Per gram, soil in your garden likely has hundreds or thousands more varieties of microbes than the stuff atop Llullaillaco, he said. "That speaks to the fact that it's such a harsh environment."

This ecosystem of fungi and bacteria is the highest ever studied on land, Schmidt said. That's fitting, perhaps, as it's found next to the highest archaeological site on the globe.

Schmidt has studied bacteria in high elevations around the world, but none in locations quite so extreme. Here, bugs must survive soil temperatures that can swing 125 degrees Fahrenheit (70 degrees Celsius) over the course of a single day, dipping as low as 5 F (minus 15 C) on a balmy summer's eve. "This is really quite unusual," said Craig Cary, a researcher at the University of Waikato in New Zealand, who wasn't involved in the research. "It makes it a special place to study."

The sheer quantity of ultraviolet radiation is also sky-high due to the elevation of Llullaillaco's summit at 22,110 feet (6,739 meters) above sea level — light has to go through less of the Earth's atmosphere, so more UV rays get through. There is also very little water. What's there comes from melted snow—the little that doesn't sublimate, or vaporize, in the brutal Atacama Desert sun.

In other words, it's an ideal location to study microbes, because the harsh conditions select for unique organisms and have made it difficult for humans to reach, let alone study.

Life at the extremes

In 2009, Schmidt, his doctoral student Ryan Lynch and the rest of his team arrived on Llullaillaco, which borders Chile and is 200 miles (320 kilometers) from anything you could consider a town. They had to plot their course up the Argentine side since land mines still riddle the Chilean approach to the mountain, placed there during the two country's near-war in 1978. After several days of acclimatization, the researchers made it most of the way up the volcano to take soil samples from just beneath the surface, Lynch said.

The team can't say for certain that they've found species that are new to science because they haven't cultured and isolated them in the lab yet, although Lynch is currently working to do just that. To identify the microbes, researchers ran the DNA sequences found in the soil through a database containing the full genomes of most known soil organisms. There weren't any exact matches, which would indicate one of the Llullaillaco species had already been sequenced.  Cary said several of the microbes were similar to those he's found atop Mount Erebus, the Antarctic volcano.

How the microbes survive such grueling conditions remains a mystery, for now. Schmidt said some of the bugs survive by breaking down trace atmospheric gases, like carbon monoxide. Louisiana State University researcher Gary King has found microbes that survive off this gas elsewhere, like at the Kilauea volcano in Hawaii.

Read more at Discovery News

Jun 20, 2012

Solstice Ushers in Summer

Welcome, summer! The season officially begins Wednesday, the longest day of the year in the Northern Hemisphere.

The summer solstice of 2012 will occur at 7:09 p.m. EDT, the instant when the sun climbs to its farthest point north of the equator. For those in the Southern Hemisphere, this solstice is the astronomical marker for the beginning of winter.

Though the actual length of the 24-hour day doesn't change, daylight will last a fraction of a second longer on June 20 than on June 19 or 21. From here on out, the days will get just a bit shorter each day until the winter solstice in December.

The reason for these fluctuations has to do with the tilt of Earth's axis. Our planet's spin is skewed 23.5 degrees. At the summer solstice, the North Pole is tilted as much as possible toward the sun. The winter solstice occurs when the planet's northernmost point is directed as far as possible away from the sun. That means that those of us north of the equator get more rays in the summer months.

The sun is always above the horizon in summertime at the North Pole, reaching its apex at the solstice. This perpetual daylight continues until the autumn equinox in September, when the sun finally sets. A months-long twilight follows until October, when the North Pole experiences round-the-clock winter darkness.

It might seem logical that during summer's hottest days, the Earth is closest to the sun. However, when it's summer in the Northern Hemisphere, our planet is actually swinging far away from our nearest star. Earth's orbit is elliptical rather than a perfect circle. On July 4 at 10 p.m. EDT, our planet will reach its "aphelion," or the point in its orbit where it is farthest from the sun. That's a distance of 94,505,849 miles (152,092,421 kilometers). The longer days of summer still keep the temperatures plenty hot, though.

This year's solstice is expected to be a scorcher for some Americans. A heat wave in the Northeast may break records on Wednesday (June 20), according to the National Weather Service. Heat advisories are in place for Wednesday in Baltimore, Md., Washington, D.C., and parts of northern Virginia, southeastern Pennsylvania and New York and New Jersey. Temperatures may top out around 100 degrees Fahrenheit in these regions.

Read more at Discovery News

Ancient Africans Made Cheese, Settled Down

More than 7,000 years ago, prehistoric people in the African Sahara were making dairy products, such as butter, yogurt and cheese.

The discovery, based on the identification of dairy fats on ancient pottery shards found in Libya, is the first to provide a definitive date for early dairy farming in Africa. Adding to findings from Europe and the Middle East, the study points to milk products as a main reason why people in many places may have chosen to give up the hunter-gatherer lifestyle in favor of a more settled existence.

“What we’re really beginning to know is that cattle were incredibly significant to early peoples,” said Julie Dunne, an archaeological scientist at the University of Bristol in the United Kingdom. “They gave a remarkably calorific source of food and allowed populations to expand dramatically. Milk and dairying seem to be so significant in human development, remarkably so.”

Plenty of research has documented the domestication of sheep, goats and cattle, as well as the use of dairy products, beginning around 9,000 years ago in parts of modern-day Turkey, 8,000 years ago in eastern Europe and 6,000 years ago in Britain.

In Africa, details have been murkier. Fossil evidence suggests the arrival of domesticated milk-producers in North Africa by about 8,000 years ago with an increase in animal numbers over the next 1,000 years, but remains are spotty. And even though archaeologists have discovered vivid rock art depicting cattle and even milking scenes in Algeria and other parts of the Sahara, it is impossible to accurately date those paintings.

For the new study, Dunne and colleagues analyzed organic residues on 81 well-dated pieces of pottery taken from the Takarkori rock shelter in the Libyan Sahara. The samples turned out to be incredibly well preserved, containing fat residues at high concentrations, probably because of the region’s dry conditions -- though the climate there was much wetter during the period considered in the new study.

Evidence showed that some pots were used to hold plant oils. But many contained chemical signatures that were unambiguously from animal fats, the researchers report today in the journal Nature. Analyses revealed the remains of dairy products made from cow, goat and sheep’s milk, dating back to between 7,200 and 5,800 years ago.

At that time, Africans had not yet developed the genetic mutations that allow people to digest milk, according to other research. So, the Sahara’s lactose-intolerant dairy farmers were likely making yogurt and cheese rather than drinking straight from the udders of their animals. Only after people learned to process dairy foods did their bodies develop the ability to drink pure milk -- through mutations that appear to have happened independently as many as three or four times in Africa.

Read more at Discovery News

Ancient Turtles Died Copulating

A 47-million-year-old fossil of nine turtle couples in the act of mating has been found.

The turtles, described in the latest Biology Letters, apparently died in the throws of passion. While deeply engaged in copulation, they drifted into poisonous water and perished, forever preserved in their lovemaking moment.

“Many animals enter a trance-like state when mating or laying eggs and it is possible that these turtles simply did not notice that they were entering poisonous waters before it was too late,” lead author Walter Joyce, a researcher at the University of Tübingen, told Discovery News.

Joyce and his colleagues analyzed the fossils, found in the Messel Pit Fossil Site between Darmstadt and Frankfurt, Germany. Numerous fossilized birds, bats, fish, frogs, snakes, insects and more were also found at the site, suggesting that at least some of them too were poisoned by what was, back in the Eocene, a volcanic lake.

The turtle couples did not all die together, but instead were found at random throughout the site of the former lake. The scientists can tell that each couple consisted of one male and one female due to tail shape and length differences, body size differences and other anatomical features. Females of this turtle species (Allaeochelys crassesculpta), for example, have a hinge in their belly shields that helped them lay relatively large eggs.

It is rare for any animal to die and be fossilized while engaged in a behavior. Other famous examples include fish that choked on large prey items and were later found fossilized in that moment. Certain dinosaurs died fighting or while brooding their nests. Such discoveries are invaluable to scientists because they reveal how animals behaved in the flesh, something that is normally just speculated upon.

“Millions of animals live and die every year and many enter the fossil record through serendipitous circumstances, but there really is no reason to enter the fossil record while you are mating,” Joyce said. “After all, the chances of both partners dying at the same time is highly unlikely and the chances of both partners being preserved afterwards even less likely.”

“The Messel turtles are therefore the only vertebrate fossils known to have died while in the process of mating and this only happened because of the highly unusual circumstances of the lake in which they lived,” he added.

The turtles initiated copulation in habitable water. They then may have gone into the intense “trance-like” state while sinking deeper into the lake. At that point, their skin probably started to absorb poisons from the build-up of volcanic gases or decay of organic matter.

Read more at Discovery News

A 50,000-Megapixel Camera Points and Shoots

A camera that can see five times better than a person with 20/20 vision is here. The resolution is 50 gigapixels, or 50,000 megapixels. Cameras used by professionals reach the 40-megapixel mark, and a typical point-and-shoot might have eight or 10. The amount of information the gigapixel camera captures in a frame is nearly as much as the amount of data stored on a PC's hard drive -- all for one picture.

The group that developed the camera was led by David Brady, professor of electrical engineering at Duke's Pratt School of Engineering, along with scientists from the University of Arizona, the University of California -- San Diego and Distant Focus Corp. The Defense Advanced Research Projects Agency (DARPA) also supported the research. The military has an obvious interest in better image processing and in decades past, has spearheaded the development of sophisticated imaging tools. But a camera like this is also useful for fields as such as astronomy.

Unlike conventional digital cameras that have a single image sensor, the gigapixel camera has 98, all working in unison. A computer puts all the disparate images together to create a single picture. Blowing up the image reveals details that the naked eye wouldn't initially see.

Michael Gehm, assistant professor of electrical and computer engineering at the University of Arizona, who led the research there, noted in a press release that to boost the camera's resolution, the team had to go beyond simply making the optical elements more complex. This time, the researchers improved the electronics and built a system of parallel processors. The camera lens focuses the light to each of the image sensors and the computer takes care of building the final image.

Read more at Discovery News

Summer Solstice and Our Wobbly World

On a clear night in the Northern Hemisphere, look up at the sky and, over a period of hours, you'll notice the stars rising in the east and setting in the west ... all except one, Polaris, the Pole Star.

It has the unique responsibility of marking, to within a few fractions of a degree, the north celestial pole. This grand title is the point in the sky toward which the Earth's axis of rotation is directed.

While Earth spins on its axis, which pops out at the north and south geographical poles (that are at different locations to the magnetic poles), it's hurtling through space in an annual orbit around the sun.

If we measure the angle of the rotation with respect to the plane of the orbit around the sun, we see it's tilted 23.5 degrees from vertical.

The tilt of the axis is responsible for the seasons we experience as the northern and southern hemispheres are alternately presented toward the sun throughout the year.

Today (June 20) the northern hemisphere is pointing directly toward the sun and so the Northern Hemisphere experiences the Summer Solstice -- or the 'longest day' -- whereas the Southern Hemisphere is plunged into winter and experiences the Winter Solstice and the 'shortest day.'

As a Northerner, I can be assured that the months of June/July will be my summer months and should, in theory, be nice and warm (although being British I could probably argue that point). However, this won't always be the case as the axis of Earth's rotation wobbles like a great celestial spinning top, completing one 'wobble' in 25,772 years.

As the axis changes its orientation -- or to use its correct term, the 'precession of the axis' -- the role of pole star passes to another. If you could hop in a time machine and whiz forward a few thousand years Polaris will be moving around with the other stars and a different one will be standing sentry.

In AD 3000, the star Gamma Cephei will be the pole star followed by Deneb in AD 10000 and Vega in Lyra will be 4 degrees away in AD 14000.

In the Southern Hemisphere, there is currently no bright star marking the south celestial pole; its nearest is a rather faint star called Sigma Octantis. This will change though, in about 3700 years time Omega Carinae will become the South Pole star, followed by Delta Velorum in AD 9200 and in AD 14000 the bright star Canopus will be within a few degrees.

Read more at Discovery News

Jun 19, 2012

It's Not Just Summer, World Keeps Warming

The world's political and environmental leaders gather in Rio de Janeiro tomorrow to assess the state of the planet's health 20 years after the first such gathering in 1992. But if science is any guide, Earth still needs some help.

Several new climate studies reveal various aspects of the same foreboding problem: the atmosphere continues to warm, glaciers continue melting and seas keep rising.

But there is a tiny bit of good news -- the United States and Europe have been able to cut their heat-trapping industrial emissions by switching to less-polluting natural gas, driving fewer miles and of course, sinking into an economic recession where fewer factories are working across much of the globe.

And while North America's mild winter, warm spring and, in some areas, hot June can't be blamed on global climate change, extreme weather events do grab the public's attention. Even though it's not entirely accurate to link climate and weather, perhaps that's not a bad thing, says Gavin Schmidt, a climate researcher at NASA's Goddard Space Science Center in New York.

"People spend a lot of time talking about the weather and love to do so," Schmidt said. "It's an odd thing because as scientists we are using people's interest in weather and weather extremes to talk about something that is connected, but isn't quite the same."

Schmidt said that rather than focusing on extreme blips in weather, it's instead important to look at changes in temperature over the long term. Scientists at the National Oceanic and Atmospheric Administration are doing just that, and reported that the past 12 months from June 2011 to May 2012 were the hottest since record-keeping began in the 1880s. The month of May 2012 was the second-hottest on record (2010 was first). And it looks like 2012 will barge into the top three hottest calendar years on record as well.

At the same time, there is occasional "noise" in the Earth's climate system, explained Ronald Prinn, professor of atmospheric sciences at the Massachusetts Institute of Technology. That means that the linear warming trend could stagger a bit from year-to-year, or decade-to-decade depending on the cooling effects of cloud cover or the ocean's ability to soak up heat.

"If you take a 10-year running average," Prinn told Discovery News. "It's clear that world has been warming for a hundred-plus years."

Some climate skeptics have pointed to the world's forests as a likely carbon "sink" that could suck up heat-trapping carbon dioxide, methane and other such gasses from burning fossil fuels. But a new study by researchers in California found that scenario might not be so simple.

As soil warms up, they found, it releases carbon dioxide made from microbes that decompose dead leaves and fallen trees. About one-third of that release comes from older soil, more than 10 years old.

"While that older material is not going to decompose really fast, there's an awful lot of it," Susan Trumbore, a University of California, Irvine, scientist who led the study, told The Washington Post.

That means that at some point in the future, the world's temperate forests could switch from a carbon sink to a carbon faucet, increasing the vicious cycle of rising CO2 causing even more CO2 to be released.

Another new study finds that Chinese officials may be cooking the books when it comes to carbon emissions.

United Kingdom-based researchers found the gap between what Chinese state authorities report as the nation's industrial emissions and the aggregate of provincial reporting has widened to 1.4 gigatons, that's about 5 percent of the world's entire CO2 emissions budget. Local officials may be padding the books to show more industrial output, while national authorities want to appear more environmentally-friendly to the West.

Either way, the new figures wipe out any gains elsewhere.

"The trends are pretty bad," Schmidt said. "All of the flattening in Europe and the U.S. are being more than matched by increases in China and India."

Despite the recent gloomy news, experts say there are solutions: replacing individual dung-burning stoves in Chinese homes with more efficient centralized power plants; developing more efficient cars, homes and light bulbs in the West; and continuing to shift away from coal as a prime energy source in both the United States and China.

Read more at Discovery News

Mass Hysteria Confirmed in New York School

A bizarre illness affecting nearly 20 students at a Western New York Junior-Senior High school now has an official diagnosis: mass hysteria.

The students, almost all of them girls, and mostly friends, began experiencing involuntary jerks and tics. Sometimes their limbs, neck or face would suddenly spasm; other times they would twitch, grunt, or shout. It was strange and troubling behavior, made all the more scary because it had no clear cause.

The students were examined by school nurses and private doctors, officials from the Health Department, the Centers for Disease Control and Prevention, and Columbia University. None could find any biological basis for the symptoms. The school was thoroughly checked for mold, lead, carbon monoxide, and other environmental contaminants; those tests also came back negative.

The Buffalo News reported, "A second study has again found that the twitches, involuntary sounds and seizures that beset a group of Le Roy students and attracted international media attention earlier this year had no environmental cause.... Those results from Leader Professional Services, encompassing nearly 6,000 pages of data from various air, soil and water tests done in and around school grounds, support the contention of treating physicians and school administrators that children in this rural community aren't being poisoned by the air they breathe or the water they drink."

The $70,000 study was embraced by superintendent Kim Cox, who posted an open letter last week announcing

    The air sampling revealed only compounds expected to be found in multi-purpose educational buildings, like Le Roy Junior/Senior High School, and most important, the levels of the substances detected were in all cases below applicable standards and criteria associated with potential health impacts and in most cases well below such standards. The substances found in the soil and water are commonly found in residential neighborhoods and parklands and, with one exception, were well below applicable standards and criteria associated with potential health impacts. There were no unexpected findings on the Junior/Senior High School Campus setting given its residential and recreational use and the past uses of the site.

In other words, extensive analysis of air, soil, and water found nothing that would cause the mysterious malady. This was the second study to thoroughly examine environmental factors in the area; the first was conducted by the New York State Health Department and released in January; it also found no environmental contaminants. Links to both studies and associated reports can be found at the Le Roy school district Web site.

This confirms what doctors have said all along: there is no environmental reason for the illness. The repeated negative findings may come as an embarrassment to many who have insisted for months that some unknown contaminant must be to blame -- for example activist Erin Brockovich repeatedly and publicly stated her belief that the symptoms were caused by environmental toxins (specifically an industrial cyanide spill in 1970).

There's little evidence that the chemical can cause the neurological symptoms seen in the students, and health officials rejected her claims; in January Brockovich was accused of fear-mongering and publicity seeking, and ordered off the school grounds.

So if it wasn't environmental contamination, what was it?

Read more at Discovery News

Delaying Vaccines: What's the Harm?

Spacing out a child's vaccination schedule has become a trend among parents wary of vaccines. A study published online today in the journal Pediatrics shows that 9.5 percent of Portland, Ore.-area parents didn't follow the recommended vaccine schedule for their children between birth and 9 months in 2009, triple the 2.5 percent in 2006.

What's the problem with limiting the number of shots per doctor's visit? Many kids don't end up with all the required shots.

"Most delayers never ended up receiving all the recommended vaccines," reports Time Magazine. Although the Portland babies with delayed shots had been to the doctor more often than those following the recommended schedule, they had received an average of 6.4 injections instead of the 10.4 their peers had. That accounts for some of the 16 percent of Oregon 2-year-olds who are not caught up with their vaccinations.

"All those extra appointments to get immunizations is costly either to families or insurance," Dr. Rodney Willoughby, a member of the American Academy of Pediatrics committee on infectious diseases and a professor of pediatrics at the Medical College of Wisconsin in Milwaukee, told HealthDay. "Second, the vaccine schedule is far from random. It's based on years of basic research, animal studies and clinical trials that look at what age kids will have the optimal immune response and therefore get the greatest level of protection and at what age they're most at risk from serious complications or death if they contracted one of the diseases."

Lead author and epidemiologist Steve Robison agrees, adding that the antibodies that babies have at birth offer protection that could interfere with vaccines taken at the wrong time.

Read more at Discovery News

Chinstrap Penguins Missing from Antarctic Island

A population of chinstrap penguins is feeling the heat, with more than one-third of a breeding colony lost in the past 20 years, new research finds.

A warming planet, which is causing sea ice in Antarctica (and elsewhere) to melt, may ultimately be to blame for the plummeting penguin population, the researchers said. That's because the chinstraps' main food, shrimp-like creatures called krill, depend on algae that attaches to that ice.

"Actually, in the '90s it was thought that the climate change would favor the chinstrap penguin, because this species prefers sea waters without ice, unlike the Adélie penguin, which prefers the ice pack," study researcher Andres Barbosa told LiveScience. He added that at the time, chinstraps, named for the thin black facial line from cheek to cheek, seemed to increase in numbers, with some new colonies being established.

The sea-ice decline in the winter, however, has become so big that it is now impacting krill populations, said Barbosa, of the National Museum of Natural Sciences in Madrid.

Counting chinstraps

Barbosa and his colleagues tallied chinstrap penguins (Pygoscelis antarctica) in the Vapour Col colony of Deception Island, in the Antarctic's South Shetland Islands in 1991-92 and 2008-09. They photographed nests in 19 subcolonies, mainly in December when chicks were hatching.

Results, which ended up including just 12 of the subcolonies due to availability of data, showed the occupied nests had declined by 36 percent between 1991 and 2008.

Barbosa and colleagues ruled out research activity as the cause for the loss since both studied populations and those used as controls showed similar patterns of decline.

Tourism is also not a likely culprit. Deception Island, built on a volcano, is one of the most visited places in Antarctica; the 2007-08 year saw some 25,000 visitors, according to the International Association of Antarctica Tour Operators (IAATO). Meanwhile, the nearby chinstrap penguin colony of Bailey Head, which is usually visited by 2,000 to 3,500 people every season, showed a decline of about 50 percent.

Rather, a dip in the krill population may be to blame, an idea supported by the fact that Adélie penguin population (P. adeliae) in the region is also declining, while the gentoo penguin population (P. papua), which has a more variable diet, is not.

(The chinstrap, gentoo and Adélie penguins are the three pygoscelid species (in the Pygoscelis genus) that inhabit the Antarctic Peninsula, the region of the Antarctic continent where the effects of climate change are more evident, the researchers noted.)

Read more at Discovery News

Jun 18, 2012

Key Part of Plants' Rapid Response System Revealed

Science has known about plant hormones since Charles Darwin experimented with plant shoots and showed that the shoots bend toward the light as long as their tips, which are secreting a growth hormone, aren't cut off.

But it is only recently that scientists have begun to put a molecular face on the biochemical systems that modulate the levels of plant hormones to defend the plant from herbivore or pathogen attack or to allow it to adjust to changes in temperature, precipitation or soil nutrients.

Now, a cross-Atlantic collaboration between scientists at Washington University in St. Louis, and the European Synchrotron Radiation Facility and the European Molecular Biology Laboratory, both in Grenoble, France, has revealed the workings of a switch that activates plant hormones, tags them for storage or marks them for destruction.

The research appeared online in the May 24 issue of Science Express and will be published in a forthcoming issue of Science.

"The enzymes are cellular stop/go switches that turn hormone responses on and off," says Joseph Jez, PhD, associate professor of biology in Arts & Sciences at WUSTL and senior author on the paper.

The research is relevant not just to design of herbicides -- some of which are synthetic plant hormones -- but also to the genetic modification of plants to suit more extreme growing conditions due to unchecked climate change.

What plant hormones do

Plants can seem pretty defenseless. After all, they can't run from the weed whacker or move to the shade when they're wilting, and they don't have teeth, claws, nervous systems, immune systems or most of the other protective equipment that comes standard with an animal chassis.

But they do make hormones. Or to be precise -- because hormones are often defined as chemicals secreted by glands and plants don't have glands -- they make chemicals that in very low concentrations dramatically alter their development, growth or metabolism. In the original sense of the word "hormone," which is Greek for impetus, they stir up the plant.

In plants as in animals, hormones control growth and development. For example, the auxins, one group of plant hormones, trigger cell division, stem elongation and differentiation into roots, shoots and leaves. The herbicide 2,4-D is a synthetic auxin that kills broadleaf plants, such as dandelions or pigweed, by forcing them to grow to the point of exhaustion.

Asked for his favorite example of a plant hormone, Corey S. Westfall brings up its chemical defense systems. Westfall, a graduate student in the Jez laboratory, who together with Chloe Zubieta, PhD, a staff scientist at the European Synchrotron Radiation Facility did most of the work on the research.

Walking through a public park in St. Louis near WUSTL, Westfall often sees oak leaves with brown spots on them. The spots are cells that have deliberately committed cell suicide to deny water and nutrients to a pathogen that landed in the center of the spot. This form of self-sterilization is triggered by the plant hormone salicylic acid.

Westfall also mentions the jasmonates, which cause plants to secrete compounds such as tannins that discourage herbivores. Tannins are toxic to insects because they bind to salivary proteins and inactivate them. So insects that ingest lots of tannins fail to gain weight and may eventually die.

A little more, a little less

Hormones, in other words, allow plants to respond quickly and sometimes dramatically to developmental cues and environmental stresses. But in order to respond appropriately, plants have to be able to sensitively control the level and activity of the hormone molecules.

The Science paper reveals a key control mechanism: a family of enzymes that attach amino acids to hormone molecules to turn the hormones on or off. Depending on the hormone and the amino acid, the reaction can activate the hormone, put it in storage or mark it for destruction.

For example, in the model plant, thale cress, fewer than 5 percent of the auxins are found in the active free-form. Most are conjugated (attached) to amino acids and inactive, constituting a pool of molecules that can be quickly converted to the active free form.

The attachment of amino acids is catalyzed by a large family of enzymes (proteins) called the GH3s, which probably originated 400 million years ago, before the evolution of land plants. The genes diversified over time: there are only a few in mosses, but 19 in thale cress and more than 100 in total.

"Nature finds things that works and sticks with them," Jez says. The GH3s, he says, are a remarkable example of gene family expansion to suit multiple purposes.

A swiveling hormone modification machine

The first GH3 gene -- from soybean -- was sequenced in 1984. But gene (or protein) sequences reveal little about what proteins do and how they do it. To understand function, the scientists had to figure out how these enzymes, which start out as long necklaces of amino acids, fold into knobbly globules with protective indentations for chemical reactions.

Unfortunately, protein folding is a notoriously hard problem, one as yet beyond the reach of computer calculations at least as a matter of routine. So most protein structures are still solved by the time-intensive process of crystallizing the protein and bombarding the crystal with X-rays to locate the atoms within it. Both the Jez lab and the Structural Biology Group at European Synchrotron Radiation Facility specialize in protein crystallization.

By good fortune, the scientists were able to freeze the enzymes in two different conformations. This information and that gleaned by mutating the amino acids lining the enzyme's active site let them piece together what the enzymes were doing.

It turned out that the GH3 enzymes, which fold into a shape called a hammer and anvil, cataylze a two-step chemical reaction. In the first step, the enzyme's active site is open allowing ATP (adenosine triphosphate, the cell's energy storage molecule) and the free acid form of the plant hormone to enter.

Once the molecules are bound, the enzyme strips phosphate groups off the ATP molecule to form AMP and sticks the AMP onto an "activated" form of the hormone, a reaction called adenylation.

Adenylation triggers part of the enzyme to rotate over the active site, preparing it to catalyze the second reaction, in which an amino acid is snapped onto the hormone molecule. This is called a transferase reaction.

"After you pop off the two phosphates," Jez says, "the top of the molecule ratchets in and sets up a completely different active site. We were lucky enough to capture that crystallographically because we caught the enzyme in both positions."

The same basic two-step reaction can either activate or inactivate a hormone molecule. Addition of the amino acid isoleucine to a jasmonate, for example, makes the jasmonate hormone bioactive. On the other hand addition of the amino acid aspartate to the auxin known as IAA marks it for destruction.

This is the first time any GH3 structure has been solved.

Read more at Science Daily

Million-Year-Old Groundwater in Maryland Water Supply

A portion of the groundwater in the upper Patapsco aquifer underlying Maryland is over a million years old. A new study suggests that this ancient groundwater, a vital source of freshwater supplies for the region east of Washington, D.C. and Baltimore, was recharged over periods of time much greater than human timescales.

"Understanding the average age of groundwater allows scientists to estimate at what rate water is re-entering the aquifer to replace the water we are currently extracting for human use," explained USGS Director Marcia McNutt. "This is the first step in designing sustainable practices of aquifer management that take into account the added challenges of sea level rise and increased human demand for quality water supplies."

This new study from the USGS, the Maryland Geological Survey (MGS) and the Maryland Department of the Environment (MDE) documents for the first time the occurrence of groundwater that is more than one million years old in a major water-supply aquifer along the Atlantic Coast. The oldest groundwater was found in the deepest parts of the aquifer, but groundwater even in shallower parts of the aquifer is tens to hundreds of thousands years old.

Groundwater age indicates the length of time that a sample of water has been in the ground since infiltrating from the land surface. This study reveals that modern pumping in southern Maryland west of the Chesapeake Bay and on the Eastern Shore is tapping groundwater resources that have accumulated in the aquifer over multiple cycles of climate change and are not quickly recharging.

The analysis shows that water flowed from the land surface into the deep aquifer during cooler periods in earth's history, when glaciers covered much of the northeastern U.S. and sea level was about 125 meters lower than it is today. During warmer periods in earth's history, such as in modern times, higher sea levels slow recharge of fresh water to the aquifer, due to a lower gradient between the recharge and discharge areas.

Modern-day pumping rates have lowered water pressures and changed water chemistry, affecting the aquifer's ability to provide freshwater for drinking and other uses. Concerns over saltwater intrusion in some areas have led water managers to increasingly move groundwater production from shallower aquifers to the deeper upper Patapsco aquifer, which has caused groundwater levels to decline.

The findings are being used to help understand the patterns and rates of groundwater movement in the aquifers of the Coastal Plain. Such information will be used by the Maryland Department of the Environment to ensure that the management and use of the State's groundwater resources are being carried out to protect its long-term sustainability. The findings bring into focus that current users are withdrawing groundwater that was recharged eons ago and accentuate the need to review current water-supply management strategies and develop new tools and models to protect this valuable resource for the future.

Read more at Science Daily

Oldest Natural Pearl Found in Arabia

French researchers have unearthed the oldest natural pearl ever found at a Neolithic site in Arabia, suggesting that pearl oyster fishing first occurred in this region of the world.

Discovered in the Emirate of Umm al Quwain, United Arab Emirates (UAE), the pearl was believed to have originated between 5547 and 5235 BC.

"Gemmologists and jewellers have popularised the idea that the oldest pearl in the world is the 5000-year-old Jomon pearl from Japan. Discoveries made on the shores of south-eastern Arabia show this to be untrue," Vincent Charpentier, Sophie Méry and colleagues at the French Foreign Ministry's archeological mission in the UAE, wrote in the journal Arabian Archaeology and Epigraphy.

Some 7,500 years old and 0.07 inches in diameter, the newly discovered pearl  is just the last of a series of findings at archeological sites in the Arabian Peninsula.

Over the years, researchers unearthed a total of 101 Neolithic pearls, coming from the large pearl oyster Pinctada margaritifera and from Pinctada radiata, a much smaller, easier to collect species, which provides higher quality pearls.

"The discovery of archaeological pearls demonstrates an ancient fishing tradition that no longer exists today," wrote the researchers.

Although diving for pearls was difficult and dangerous, mother-of-pearl was an important resource in the economy of local Neolithic societies, said the researchers.

The large valves of P. margaritifera's were used to make fish hooks for the capture of fish as large as tuna and sharks, while spherically shaped pearls were collected for their esthetic value and for funeral rites.

Indeed, the Umm al Quwain pearl, which was not drilled, had been recovered from a grave.

According to the researchers, findings at local necropolis reveal that pearls were often placed on the deceased's face, often above the upper lip.

Read more at Discovery News

Aboriginal Rock Art is 28,000 Years Old

Aboriginal rock art found in remote Australia has been dated at 28,000 years old, experts said Monday, prompting new speculation that indigenous communities were among the world's most advanced.

Archaeologists picked up the fragment in inaccessible wilderness in Arnhem Land in the country's north a year ago, and recent carbon dating of its charcoal drawing has placed it among some of the oldest art on the planet.

"One of the things that makes this little fragment of art unique is that it is drawn in charcoal... which means we could directly date it," said Bryce Barker, who found and first analysed the granite rock.

Barker said given it was one of the oldest known pieces of rock art on earth, it showed that Aboriginal people were responsible for some of the earliest examples.

Barker said the find ranks among rock art sites such as France's Chauvet caves dated at older than 30,000 years and caves in northern Spain now thought to be 40,000 years old.

"The fact remains that any rock art that is older than 20,000 years is very unique around the world," said Barker, a professor at the University of Southern Queensland.

"So it makes this amongst some of the oldest art in the world.

"And we're convinced that we'll find older and the reason is that the site this comes from, we know that Aboriginal people started using this site 45,000 years ago."

The find was made at a massive rock shelter named Narwala Gabarnmang, which is covered on its ceiling and pillars with rock art, and only accessible by a 90 minute helicopter journey from the outback town of Katherine.

Archaeologists were first taken to the site five years ago by its Aboriginal custodians, the Jawoyn, who wanted to preserve the art and at the same time unlock some of the secrets of its history.

Read more at Discovery News