Spot Where Julius Caesar Stabbed Discovered

Archaeologists believe they have found the first physical evidence of the spot where Julius Caesar died, according to a new Spanish National Research Council report.

Caesar, the head of the Roman Republic, was stabbed to death by a group of rival Roman senators on March 14, 44 B.C, the Ides of March. The assassination is well-covered in classical texts, but until now, researchers had no archaeological evidence of the place where it happened.

Now, archaeologists have unearthed a concrete structure nearly 10 feet wide and 6.5 feet tall (3 meters by 2 meters) that may have been erected by Caesar's successor to condemn the assassination. The structure is at the base of the Curia, or Theater, of Pompey, the spot where classical writers reported the stabbing took place.

"We always knew that Julius Caesar was killed in the Curia of Pompey on March 15th 44 B.C. because the classical texts pass on so, but so far no material evidence of this fact, so often depicted in historicist painting and cinema, had been recovered," Antonio Monterroso, a researcher at the Spanish National Research Council, said in a statement.

Classical texts also say that years after the assassination, the Curia was closed and turned into a memorial chapel for Caesar. The researchers are studying this building along with another monument in the same complex, the Portico of the Hundred Columns, or Hecatostylon; they are looking for links between the archaeology of the assassination and what has been portrayed in art.

"It is very attractive, in a civic and citizen sense, that thousands of people today take the bus and the tram right next to the place where Julius Caesar was stabbed 2,056 years ago," Monterroso said.

From Discovery News

Understanding Stonehenge: Two Explanations

After centuries of puzzling over the meaning of Stonehenge, laser-equipped researchers have concluded that the prehistoric monument was built to show off the solstices.

Apart from revealing 71 new images of Bronze Age axeheads, which bring the number of this type of carvings known at Stonehenge to 115, the English Heritage groundbreaking analysis showed that the stones were shaped and crafted differently in various parts of the stone circle.

In particular, the stones first seen when approaching the monument from the north-east were completely "pick dressed." Stonehenge workers removed their brown and grey surface crust to show a bright, grey-white surface that would glisten at sunset on the shortest day of the year and in the dawn light on the longest day.

According to the researchers, this provides an almost definitive proof that it was the intent of Stonehenge's builders to align the monument with the two solstices along a north-east/south-west axis.

Located in the county of Wiltshire, at the center of England's densest complex of Neolithic and Bronze Age monuments, Stonehenge has been the subject of myth, legend and -- more recently -- scientific research for more than eight centuries.

The mysterious circle of large standing stones has been interpreted in the most disparate ways -- as a temple for sun worship, a temple of the ancient druids, a healing center, a burial site and a huge calendar.

The new laser findings appear to be compatible with two main theories taking shape in recent years to explain the monument's purpose.

According to archaeologist Mike Parker Pearson, head of the Stonehenge Riverside Project, the iconic monument was built as a grand act of union after a long period of conflict between east and west Britain.

Another theory, posed by archaeologists Geoff Wainwright and Timothy Darvill, says Stonehenge was a destination to which the sick traveled from around Europe to be healed by its magical powers.

"The scanning work at Stonehenge is really important and has opened our eyes to many new aspects of Neolithic technology," Darvill, professor of archaeology in the School of Applied Sciences at Bournemouth University, England, told Discovery News.

Darvill and Wainwright made one of the most significant findings in 2005, when they located the quarry where the bluestones, which form Stonehenge's inner circle, were cut around 2500 B.C.

The archaeologists discovered a "small crag-edged promontory with a stone bank across its neck" at one of the highest points of Carn Menyn, a mountain in the Preseli Hills of Pembrokeshire, in southwest Wales.

The site, which measures less than half a hectare, is characterized by numerous prone pillar stones with clear signs of working. Darrvill described it as "a veritable Aladdin's Cave of made-to-measure pillars for aspiring circle builders."

The bluestones weighed about four tons and were between six and nine feet in height and would have been transported 240 miles to the famous site at Salisbury Plain in Wiltshire.

According to Darvill, the color and the presence of distinctive white spots made the Preseli Hills stones very pleasing aesthetically.

"Importantly, the methods of working the bluestones seems to be the same as for the central Trilithons and serves to support the idea I put forward some time ago that these two components of the monument were contemporary and somehow linked," Darvill said.

According to the archaeologist, the huge stones were taken on such a journey from their Welsh location because they were believed to harbor great powers.

In 2008, Darvill and Wainwright excavated a small patch of earth at Stonehenge. The dig unearthed about 100 pieces of organic material from the original bluestone sockets and provided the most accurate dating for their erection, pinpointing the bluestone construction to 2300 B.C. It also produced a large number of bluestone chippings, as if people flaked them off to create little amulet bits.

The presence of a large number of human remains in tombs near Stonehenge showing physical injury and disease and analysis of teeth reveal that around half of the corpses were not native to the Stonehenge area and suggested Stonehenge served as a center for healing, said the archaeologists.

Attracted by the powers of the bluestones, the sick and injured would have come to the site from far away.

"The new work indirectly supports the healing hypothesis as it shows the importance of the stones from Wales," Darvill said.

"It also shows that most of them have had bits chipped off them and some have been reduced to stumps by removals exactly as we suggested was the case," he added.

But according to Mike Parker Pearson, the enigmatic stone circle had nothing to do with sickness and diseases. On the contrary, it was built as a grand act of union after a long period of conflict between east and west Britain.

"Stonehenge itself was a massive undertaking, requiring the labor 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.

Because of Stonehenge's solstice-aligned avenue, prehistoric people would have seen the spot as nothing less than the "center of the world."

According to Parker Pearson, the discovery of the winter sunset axis at Stonehenge by the laser scan project supports his previous findings.

Read more at Discovery News

House-Sized Asteroid to Buzz Earth Today

As far as errant chunks of space rock go, this one's a tiddler.

But this particular asteroid -- called 2012 TC4 -- is going to fly past the Earth at a distance of only 95,000 kilometers (59,000 miles), or one-quarter the Earth-moon distance. As far as near-misses go, that's the outer edge of the bulls-eye.

Although 2012 TC4 will likely garner an impressive array of scary headlines, even if it did hit us, it's unlikely the space rock -- depending on its composition -- would do much damage. It's only 17 meters (56 feet) wide.

"Small asteroid 2012 TC4 will safely pass Earth Oct 12 at just .25 the distance to our moon's orbit," said scientists at NASA's Asteroid Watch program via a Twitter update.

According to Spaceweather.com, 2012 TC4 could be spotted by amateur astronomers: "There is no danger of a collision, but the 16 meter-wide space rock will be close enough to photograph through backyard telescopes as it brightens to approximately 14th magnitude. NASA hopes to ping this this object with radar, refining its orbit and possibly measuring its shape."

In related (and potentially more critical) news, a 500-meter (1,640 feet) wide hazardous near-Earth asteroid has been re-discovered by an amateur astronomer of the ESA's space hazards program. Erwin Schwab, from Germany, used ESA's Optical Ground Station in Tenerife, Spain -- a system sponsored by the Agency's Space Situational Awareness program.

Asteroid 2008 SE85 was originally discovered by the Catalina Sky Survey in September 2008, but it disappeared by October of the same year. Astronomers considered the interplanetary interloper "lost" as its orbit wasn't well defined.

Fortunately, Schwab had the tenacity to scan a patch of sky where the asteroid may have drifted into. "I found the object on the evening of Saturday, 15 September, while checking the images on my computer," he said. "I then saw it again at 01:30 on Sunday morning – and that was my birthday! It was one of the nicest birthday presents."

The amateur astronomer's find has been confirmed by a number of observatories world-wide including the US-based Minor Planet Center.

Read more at Discovery News

Mystery of Ball Lightning Solved?

A team of Australian scientists believe they have uncovered the cause of one of nature's most bizarre phenomenon - ball lightning.

Ball lightning, typically the size of a grapefruit, is a rarely seen event that lasts up to 20 seconds.

"Ball lightning has been reported by hundreds of people ... for hundreds of years and it has been a mystery," says CSIRO scientist John Lowke, lead author of a new study published in the Journal of Geophysical Research Atmospheres.

Previous theories have suggested microwave radiation, oxidizing aerosols, nuclear energy, dark matter, antimatter, and even black holes as possible causes. One recent theory suggests it is burning silicon that has been vaporized by a lightning strike.

To unravel the mystery Lowke and colleagues at the CSIRO and the Australian National University turned their attention to reports of ball lightning forming near windows.

"There are many observations of ball lightning appearing from a glass window either in a house (or) ... in the cockpit of an aircraft," Lowke says. "If it's burning silicon, how did it come in?"

After hitting the ground and lighting the sky, lightning strikes leave behind a trail of charged particles, or ions. In most cases, these positive and negative ions recombine in a split seconds, says Lowke. Any remaining ions travel down to the ground.

Lowke's theory, is that some of these ions can accumulate on the outside of non-conducting surfaces such as a window.

"These ions pile up and produce an electrical field which penetrate the glass," he says.

Lowke says the field gives free electrons on the inside of the window enough energy to knock off electrons from surrounding air molecules, as well as release photons, creating a glowing ball.

Recreating it in the lab

"This is the first paper which gives a mathematical solution explaining the birth or initiation of ball lighting," says Lowke.

He says the next step is to use the theory to replicate ball lightning in the laboratory. That may still prove difficult, as it would require equipment capable of producing 100 million volts.

But a ball lightning event seen by a former US Air Force pilot suggests another approach.

While flying a C-133A cargo plane from California to Hawaii in the mid 1960s, former Lieutenant Don Smith saw two horns of Saint Elmo's fire appear on the plane's randome (radar cover), followed by ball lightning inside the cockpit.

"It looked as if the airplane had bull's horns...they were glowing with the blue of electricity," says Lowke. "(It) was driven by ions from the aircraft radar operated at maximum power during a dense fog."

Read more at Discovery News

Fact Check: Baby Earth At 9,000 Years Old

U.S. House Rep. Paul Broun, a Georgia Republican, doesn't believe in evolution, the Big Bang theory, or the teachings of embryology. In fact, in a Sept. 27 talk at Liberty Baptist Church in Hartwell, Ga., the member of the House Committee on Science, Space and Technology, who is also a medical doctor, called those areas of science "lies straight from the pit of hell."

But Broun also advanced his own theory of life on Earth.

"You see, there are a lot of scientific data that I've found out as a scientist that actually show that this is really a young Earth," he said. "I don't believe that the Earth's but about 9,000 years old. I believe it was created in six days as we know them. That's what the Bible says."

 Broun's creationist viewpoint stands in opposition to what scientific research reveals about the age of the planet. In fact, Earth formed 4.54 billion years ago — and humanity is rather lucky not to be seeing the planet on its 9,000th birthday. Earth was formed by the colliding and coming together of massive space objects called planetesimals, said Richard Carlson, a geochemist at the Carnegie Institution who has studied some of Earth's oldest rocks. The force of the impacts would have melted rock, leaving Earth molten for hundreds of thousands of years, Carlson told LiveScience.

"Nine thousand years after the last giant impact — there likely were several big impacts during the growth of the planet — the surface of Earth, to a considerable depth, likely was molten rock," he said.

Creationist beliefs

Broun is far from the only believer in a literal, or Biblical, creation. According to a Gallup poll conducted in June, 46 percent of Americans believe God created humans in their present form within the last 10,000 years, a creationist belief. Only 15 percent said they believed in evolution without God's hand, while 32 percent said they believed in evolution guided by God.

That survey did not ask adults how old they believed Earth to be, but estimates based on literal interpretation of the Bible normally range from 6,000 to 8,000 years. (It's not clear why Broun believes in a 9,000-year-old Earth.)

The most popular 6,000-year-old figure comes from James Ussher, a 16th-century Irish clergyman. Ussher, whose position as Archbishop of Armagh made him head of the church in Ireland, published two works in the 1650s using genealogies from the Bible to date the creation of the world to Oct. 23, 4004 B.C.

Other estimates differ based on the use of different Bible translations and whether biblical scholars take the Bible's six-day creation period literally or assume the "days" to be longer periods of time.
 
What the science says

Scientists, on the other hand, have reached a surprisingly precise answer as to the age when Earth and the rest of the solar system began to solidify: between 4.567 and 4.568 billion years — the equivalent of knowing a person's birthday within two days, Carlson said.

This age range is calculated using isotopes, or variants of chemical elements. For the purposes of dating the solar system, researchers use lead and uranium isotopes. They measure the ratios of different types of isotopes from Earth and from meteorites. Because these objects all formed from the same pool of cosmic dust and gas during the birth of the solar system, the measurements enable researchers to determine how long ago the objects separated from that common pool.

As it turns out, these numbers mesh quite nicely with the ages of the oldest rocks known on Earth, which would have formed after the planet stabilized and cooled. The best estimate for the age of the oldest rocks on Earth, found near Hudson Bay in Quebec, is 4.4 billion years, according to Carlson. (The date is somewhat controversial, with some scientists believing 3.8 billion years is a closer date for those rocks.) Meanwhile, the oldest mineral grains found on Earth, zircons from Western Australia, date back 4.36 billion years.

The cooling and solidifying of the planet likely happened quickly on a geologic time scale, on the order of hundreds of thousands to a million years, Carlson said. But Adam and Eve wouldn't have found Earth hospitable for a very long time. Even at 2.5 billion years of age, the planet had a flip-flopping atmosphere that periodically looked like something you'd see on one of Saturn's moons today.

Read more at Discovery News

Soft-Shelled Turtles Urinate Through Mouth

Chinese soft-shelled turtles are exquisitely adapted to their aquatic lifestyle, sitting contentedly on the bottom of brackish muddy swamps or snorkelling at the surface to breath. According to Y. K. Ip from the National University of Singapore, they even immerse their heads in puddles when their swampy homes dry up: which intrigued Ip and his colleagues. Why do these air-breathing turtles submerge their heads when they mainly depend on their lungs to breathe and are unlikely to breathe in water?

Given that some fish excrete waste nitrogen as urea -- in addition to ammonia -- and expel the urea through their gills, the team wondered whether the turtles were plunging their heads into water to excrete waste urea through their mouths, where they have strange gill-like projections. Ip and his colleagues publish their discovery that turtles effectively urinate through the mouth in The Journal of Experimental Biology at http://jeb.biologists.org.

Purchasing turtles from the local China Town wet market and immersing them in water for 6 days, the team measured the amount of urea that passed into the turtles' urine and found that only 6% of the total urea that the animals produced was excreted through the kidneys. Removing the turtles from the water and providing them with a puddle to dip their heads into, the team noticed that the turtles submerged their heads occasionally and could remain underwater for periods lasting up to 100 minutes. They also calculated the excretion rate of urea through the mouth by measuring the amount of urea that accumulated in the water and found that it was as much as 50 times higher than the excretion rate through the cloaca. And when the team injected urea into the turtles and measured their blood- and saliva-urea levels, they realised that the saliva-urea levels were 250 times greater than in the blood. The turtles were dipping their heads into water to excrete urea through their mouths.

Knowing this, the team reasoned that the animals must produce a specialised class of protein transporters in their mouths to expel the waste and, as these transporters can be deactivated by phloretin, the team decided to test the effect of phloretin on the turtle's ability to excrete urea. When the turtles were supplied with phloretin in their puddle of water, they were unable to excrete urea from their mouths when they submerged their head. And when the team analysed the turtles' cDNA, they found that the animals carried a gene that was very similar to urea transporters found in other animals. Finally, they checked to see if the turtles express this gene in their mouths and found evidence of the mRNA that is necessary to produce the essential urea transporter, allowing the reptiles to excrete urea waste through the mouth.

Read more at Science Daily

Nearby Super-Earth Likely a Diamond Planet

New research led by Yale University scientists suggests that a rocky planet twice Earth's size orbiting a nearby star is a diamond planet.

"This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth," said lead researcher Nikku Madhusudhan, a Yale postdoctoral researcher in physics and astronomy. "The surface of this planet is likely covered in graphite and diamond rather than water and granite."

The paper reporting the findings has been accepted for publication in the journal Astrophysical Journal Letters.

The planet -- called 55 Cancri e -- has a radius twice Earth's, and a mass eight times greater, making it a "super-Earth." It is one of five planets orbiting a sun-like star, 55 Cancri, that is located 40 light years from Earth yet visible to the naked eye in the constellation of Cancer.

The planet orbits at hyper speed -- its year lasts just 18 hours, in contrast to Earth's 365 days. It is also blazingly hot, with a temperature of about 3,900 degrees Fahrenheit, researchers said, a far cry from a habitable world.

The planet was first observed transiting its star last year, allowing astronomers to measure its radius for the first time. This new information, combined with the most recent estimate of its mass, allowed Madhusudhan and colleagues to infer its chemical composition using models of its interior and computing all possible combinations of elements and compounds that would yield those specific characteristics.

Astronomers had previously reported that the host star has more carbon than oxygen, and Madhusudhan and colleagues confirmed that substantial amounts of carbon and silicon carbide, and a negligible amount of water ice, were available during the planet's formation.

Astronomers also thought 55 Cancri e contained a substantial amount of super-heated water, based on the assumption that its chemical makeup was similar to Earth's, Madhusudhan said. But the new research suggests the planet has no water at all, and appears to be composed primarily of carbon (as graphite and diamond), iron, silicon carbide, and, possibly, some silicates. The study estimates that at least a third of the planet's mass -- the equivalent of about three Earth masses -- could be diamond.

"By contrast, Earth's interior is rich in oxygen, but extremely poor in carbon -- less than a part in thousand by mass," says co-author and Yale geophysicist Kanani Lee.

The identification of a carbon-rich super-Earth means that distant rocky planets can no longer be assumed to have chemical constituents, interiors, atmospheres, or biologies similar to those of Earth, Madhusudhan said. The discovery also opens new avenues for the study of geochemistry and geophysical processes in Earth-sized alien planets. A carbon-rich composition could influence the planet's thermal evolution and plate tectonics, for example, with implications for volcanism, seismic activity, and mountain formation.

"Stars are simple -- given a star's mass and age, you know its basic structure and history," said David Spergel, professor of astronomy and chair of astrophysical sciences at Princeton University, who is not a co-author of the study. "Planets are much more complex. This 'diamond-rich super-Earth' is likely just one example of the rich sets of discoveries that await us as we begin to explore planets around nearby stars."

In 2011, Madhusudhan led the first discovery of a carbon-rich atmosphere in a distant gas giant planet, opening the possibility of long-theorized carbon-rich rocky planets (or "diamond planets"). The new research represents the first time that astronomers have identified a likely diamond planet around a sun-like star and specified its chemical make-up. Follow-up observations of the planet's atmosphere and additional estimates of the stellar composition would strengthen the findings about the planet's chemical composition.

Read more at Science Daily

New Theory of Early Animal Evolution

A New York Medical College developmental biologist whose life's work has supported the theory of evolution has developed a concept that dramatically alters one of its basic assumptions -- that survival is based on a change's functional advantage if it is to persist. Stuart A. Newman, Ph.D., professor of cell biology and anatomy, offers an alternative model in proposing that the origination of the structural motifs of animal form were actually predictable and relatively sudden, with abrupt morphological transformations favored during the early period of animal evolution.

Newman's long view of evolution is fully explained in his perspective article, "Physico-Genetic Determinants in the Evolution of Development," which is to be published in the October 12 issue of the journal Science, in a special section called Forces in Development.

Evolution is commonly thought to take place opportunistically, by small steps, with each change persisting, or not, based on its functional advantage. Newman's alternative model is based on recent inferences about the genetics of the single-celled ancestors of the animals and, more surprisingly, the physics of "middle-scale" materials.

Animal bodies and the embryos that generate them exhibit an assortment of recurrent "morphological motifs" which, on the evidence of the fossil record, first appeared more than a half billion years ago. During embryonic development of present-day animals, cells arrange themselves into tissues having non-mixing layers and interior cavities. Embryos contain patterned arrangements of cell types with which they may form segments, exoskeletons and blood vessels. Developing bodies go on to fold, elongate, and extend appendages, and in some species, generate endoskeletons with repeating elements (e.g., the human hand).

These developmental motifs are strikingly similar to the forms assumed by nonliving condensed, chemically active, viscoelastic materials when they are organized by relevant physical forces and effects, although the mechanisms that generate the motifs in living embryos are typically much more complex. Newman proposes that the ancestors of the present-day animals acquired these forms when ancient single-celled organisms came to reside in multicellular clusters and physical processes relevant to matter at this new (for cellular life) spatial scale were immediately mobilized.

The unicellular progenitors are believed to have contained genes of the "developmental-genetic toolkit" with which all present-day animals orchestrate embryonic development, though they used the genes for single-cell functions. It was precisely these genes whose products enabled the ancestral clusters to harness the middle-scale physical effects that produced the characteristic motifs. And since not every ancestral cluster contained the same selection of toolkit genes, different body forms arose in parallel, giving rise to the modern morphologically distinct animal phyla.

Read more at Science Daily

Sandusky and the Science of Self-Delusion

For sexually abusing 10 boys while working as an assistant football coach at Penn State, Jerry Sandusky received a sentence this week of between 30 and 60 years in prison.

And yet, Sandusky continues to insist that he is innocent.

"They could take away my life, they could make me out as a monster, they could treat me as a monster, but they can't take away my heart," he said in a recorded statement. "In my heart, I know I did not do these alleged disgusting acts. My wife has been my only sexual partner and that was after marriage. Our love continues."

Despite overwhelming evidence and testimony against him, Sandusky appears to truly believe he did nothing wrong.

How can he possibly be so completely delusional?

Sandusky's faith in his own lies is, in fact, an extremely common and very human trait, experts say. And even though his denial led him to commit destructive and terrible acts far worse than what most people would ever do, his ability to distort and then reinforce his own sense of the truth illustrates the extreme flexibility of the human mind to alter memories.

"Self-deception can become deeply entrenched if it's something we practice and continue to practice and continue to continue to practice," said Robert Trivers, an evolutionary biologist at Rutgers University and author of "The Folly of Fools: The Logic of Deceit and Self-Deception in Human Life."

"You deny the facts, then you deny that you deny them, then new evidence comes in and you deny that," he added. "To get Sandusky into the state of mind we see him in at the present requires that he had been engaging in this kind of denial and self-deception for years and years and years as part of making this behavior acceptable to himself and even admirable, since he thought he was setting the foundation to aid children."

Just about all of us deceive ourselves to some degree. Studies show, for example, that most people rate themselves as higher than average on scales of attractiveness, intelligence, generosity and other measures of appeal to others.

In many ways, these kinds of mild delusions can be a good thing, providing a confidence boost that improves our lives. Whether it's about the size of a pimple or the likelihood of succeeding at opening a new restaurant, little lies can lead to success.

From an evolutionary standpoint, Ariely said, learning to believe our own lies can boost our chances of survival, helping us take risks and gamble in uncertain situations.

"Ask yourself whether you would always want to know the truth about yourself. Ask yourself whether you want your husband to always tell the truth," said Dan Ariely, a psychologist and behavioral economist at Duke University, and author of "The Honest Truth About Dishonesty: How We Lie to Everyone--Especially Ourselves."

There are lots of benefits to seeing ourselves as better than we are."

It can also work the other way: On a daily basis, we delude ourselves about the safety of getting in our cars, believing that we're in control and unlikely to die. Likewise, many people think they're less likely to succumb to a heart attack than they really are, and those beliefs fuel bad choices.

In one study, Ariely and colleagues gave two groups of people an SAT-like test and told them that they would be paid for each correct answer. One group received versions of the test with answers at the bottom, though they were told not to peek until after they had finished. The other group had no choice but to do the work on their own.

When given the option, the researchers found, lots of test-takers cheated by looking at the answers before they were done -- leading the group that was given answers to score consistently better than the group that received only the questions.

But that's not all. Many of the cheaters actually came to believe that they were as good as their deceptive scores would indicate.

In subsequent tests that did not provide answers, the cheating group predicted they would do as well as they had the first time around, and they ended up losing money on that bet. People who received a certificate proclaiming the scores they had earned through cheating were even more convinced about their superior skills.

Results like these illustrate how people so end up lying on their resumes, Ariely said. As exaggerations accumulate on an official document, those lies begin to reinforce false memories.

For many people, one small lie often leads to another, and that's where trouble begins, especially when combined with dangerous desires.

Read more at Discovery News

Mummy with Mouthful of Cavities Discovered

Around 2,100 years ago, at a time when Egypt was ruled by a dynasty of Greek kings, a young wealthy man from Thebes was nearing the end of his life.

Rather than age, he may have succumbed to a sinus infection caused by a mouthful of cavities and other tooth ailments, according to new research on the man's odd dental filling.

Recently published CT scans of his mummified body allowed researchers to reconstruct details of his final days.

The man, whose name is unknown, was in his 20s or early 30s, and his teeth were in horrible shape. He had "numerous" abscesses and cavities, conditions that appear to have resulted, at some point, in a sinus infection, something potentially deadly, the study researchers said.

The pain the young man suffered would have been beyond words and drove him to see a dental specialist. Dentistry was nothing new in Egypt, ancient records indicate that it was being practiced at least as far back as when the Great Pyramids were built. Dental problems were also not unusual, the coarsely ground grain ancient Egyptians consumed was not good for the teeth.

A modern-day dentist would have a hard time dealing with the young man's severe condition and one can imagine that the ancient dentist must have felt overwhelmed. The researchers noted that even today infections associated with the teeth pose a "serious health risk."

Nevertheless the ancient specialist tried something to relieve his suffering. Using a piece of linen, perhaps dipped in a medicine such as fig juice or cedar oil, the expert created a form of "packing" in the young man's biggest and perhaps most painful cavity, located on the left side of his jaw between the first and second molars.

The packing acted as a barrier to prevent food particles from getting into the cavity, with any medicine on the linen helping to ease the pain, the study researchers said. Sadly, while this likely helped the young man out, he would succumb shortly after, perhaps in just a matter of weeks. Researchers can't say for sure the cause of death, but the sinus infection is a good possibility.

When he died he was mummified, his brain and many of his organs taken out, resin put in and his body wrapped. Curiously, embalmers left his heart inside the body, a sign perhaps of his elite status, researchers say.

After being mummified he was likely put in a coffin and given funerary rites befitting someone of his wealth and stature. Where he was laid to rest in Thebes isn't known, as his story picks up again in 1859 when James Ferrier, a businessman and politician, brought the mummified body (the whereabouts of the coffin is unknown) to Montreal, where today it lies in the Redpath Museum at McGill University.

Reconstructing his story

To figure out the mummy's story, researchers led by Andrew Wade, then at the University of Western Ontario, used new high-resolution CT scans of his teeth and body, reporting their dental-packing discovery recently in the International Journal of Paleopathology. Researchers said this is the first known case of such packing treatment done on an ancient Egyptian. Unlike a modern-day dental filling, this one didn't aim to stabilize the tooth.

"The dental treatment, filling a large inter-proximal cavity [a cavity between two teeth] with a protective, likely medicine-laden, barrier is a unique example of dental intervention in ancient Egypt," the team writes in their journal article.

Read more at Discovery News

Must-See Hyperphotos: The Ultimate Zoom

We've all seen movies like Limitless that open with the following scene: a zoom shot from afar that seems to infinitely descend into microscopic detail. To a degree, Google Earth gives us the same effect, albeit with blurrier end results.

So if you're looking for a crisper trip down the magnified wormhole, I suggest you have a peak at Jean-Francois Rauzier's Hyperphotos. They're 10,000 times the resolution of a regular photo and will allow you to get up close and personal like never before.

Actually, Rauzier's Hyperphotos are hundreds -- even thousands -- of images that he's stitched together with Photoshop. After photographing his subject from every angle for an hour or two, he begins the tedious task of stretching, bending and multiplying his images into a seamless collage that resembles a single photo.

While Rauzier's photos are more artistic playscape than true-to-life documentation, they're absurdly fun to explore. But procrastinators beware, the potential to waste mammoth amounts of time exploring every last excruciating detail is very real.

Read more at Discovery News

Jurassic Park Won't Happen: Dino DNA Dead

In "Jurassic Park," scientists extract 80-million-year-old dino DNA from the bellies of mosquitoes trapped in amber. Researchers may never be able to extract genetic material that old and bring a T. rex back to life, but a new study suggests DNA can survive in fossils longer than previously believed.

The oldest DNA samples ever recovered are from insects and plants in ice cores in Greenland up to 800,000 years old. But researchers had not been able to determine the oldest possible DNA they could get from the fossil record because DNA's rate of decay had remained a mystery.

Now scientists in Australia report they've been able to estimate this rate based on a comparison of DNA from 158 fossilized leg bones from three species of the moa, an extinct group of flightless birds that once lived in New Zealand. The bones date between 600 and 8,000 years old and importantly all come from the same region.

Temperatures, oxygenation and other environmental factors make it difficult to detect a basic rate of degradation, researcher Mike Bunce, from Murdoch University's Ancient DNA lab in Perth, explained in a statement.

"The moa bones however have allowed us to study the comparative DNA degradation because they come from different ages from a region where they have all experienced the same environmental conditions," Bunce said.

Based on this study, Bunce and his team put DNA's half-life at 521 years, meaning half of the DNA bonds would be broken down 521 years after death, and half of the remaining bonds would be decayed another 521 years after that, and so on. This rate is 400 times slower than simulation experiments predicted, the researchers said, and it would mean that under ideal conditions, all the DNA bonds would be completely destroyed in bone after about 6.8 million years.

"If the decay rate is accurate then we predict that DNA fragments of sufficient length will preserve in frozen fossil bone of around one million years in age," Bunce said.

But he cautioned that more research is needed to examine the other variables in the breakdown of DNA.

Read more at Discovery News

Regenerated Body Parts Not as Good as Originals

When an animal grows back a missing body part, the replacement is not as good as the original, new research confirms.

It's been known for a while that regenerated lobster claws and eyes tend to be much smaller, but now a study on regenerated lizard tails reveals that they are far from identical to the first ones.

"The regenerated lizard tail is not a perfect replica," Rebecca Fisher, an associate professor in Arizona State University's School of Life Sciences, and at the UA College of Medicine – Phoenix, said in a press release. "There are key anatomical differences including the presence of a cartilaginous rod and elongated muscle fibers spanning the length of the regenerated tail."

The findings are published in a pair of articles featured in a special October edition of the journal The Anatomical Record.

Fisher and her team studied the regenerated tails of the green anole lizard (Anolis carolinensis). This lizard likely evolved the regrowth ability since predators often bite the lizard's tail off. The little reptile can lose its tail in other ways too.

The researchers determined that the new tails have a single, long tube of cartilage instead of vertebrae, as in the original. Long muscles also span the length of the regenerated tail compared to shorter muscle fibers found in the original.

"These differences suggest that the regenerated tail is less flexible, as neither the cartilage tube nor the long muscle fibers would be capable of the fine movements of the original tail, with its interlocking vertebrae and short muscle fibers," Fisher said. "The regrown tail is not simply a copy of the original, but instead is a replacement that restores some function."

The animal also has to expend quite a lot of energy to regrow the missing part. People who break off the claws on a living lobster and say, "They'll just grow back," are actually leaving that animal in a dangerous, impaired state.

On a happier note, it's still promising to know that some animals can achieve this feat in the first place. Perhaps the method could be extended to humans, once some key questions are answered.

"Using next-generation technologies, we are close to unlocking the mystery of what genes are needed to regrow the lizard tail," said Kenro Kusumi, an associate professor in ASU's School of Life Sciences in the College of Liberal Arts and Sciences, and co-author of the papers. "By supercharging these genes in human cells, it may be possible to regrow new muscle or spinal cord in the future."

Read more at Discovery News

Flirting Can Pay Off for Women, Study Finds

When Madeleine Albright became the first female U.S. Secretary of State, she led high-level negotiations between mostly male foreign government leaders. In 2009, comedian Bill Maher asked Albright if she ever flirted on the job and she replied, "I did, I did." Flirtatiousness, female friendliness, or the more diplomatic description "feminine charm" is an effective way for women to gain negotiating mileage, according to a new study by Haas School of Business Professor Laura Kray.

"Women are uniquely confronted with a tradeoff in terms of being perceived as strong versus warm. Using feminine charm in negotiation is a technique that combines both," says Kray, who holds the Warren E. and Carol Spieker Chair in Leadership at the Haas School.

The study, "Feminine Charm: An Experimental Analysis of its Costs and Benefits in Negotiations," was published in October in the journal Personality and Social Psychology Bulletin and co-authored by Haas PhD alumna Connson C. Locke of the London School of Economics and Haas PhD candidate Alex B. Van Zant.

Flirtation that generates positive results, says Kray, is not overt sexual advances but authentic, engaging behavior without serious intent. In fact, the study found female flirtation signals attractive qualities such as confidence, which is considered essential to successful negotiators.

To determine whether women who flirt are more effective in negotiating than men who flirt, the researchers asked 100 participants to evaluate to what extent they use social charm in negotiation on a one-to-seven scale.

Earlier that week, the participants evaluated their partners' negotiating effectiveness. Women who said they used more social charm were rated more effective by their partners. However, men who said they used more social charm were not regarded as more effective.

In the second experiment, the researchers asked subjects to imagine they were selling a car worth $1,200 and asked for how much would they sell the car. Next, the subjects read one of two scenarios about a potential buyer named Sue. The first group meets Sue, who shakes hands when she meets the seller, smiles, and says, "It's a pleasure to meet you,." and then "What's your best price?" in a serious tone. The second group reads an alternate scenario in which Sue greets the seller by smiling warmly, looking the seller up and down, touching the seller's arm, and saying, "You're even more charming than over email," followed by a playful wink and asking, "What's your best price?"

The result? Male sellers were willing to give the "playful Sue" more than $100 off the selling price whereas they weren't as willing to negotiate with the "serious Sue." Playful Sue's behavior did not affect female car sellers.

Kray says many of her students who are senior women executives admit they love to flirt and describe themselves as "big flirts." Kray maintains flirting is not unprofessional if it remains playful and friendly.

Read more at Science Daily

Bioenergy: The Broken Promise

Biofuels are going to save us from climate threats and the oil crisis, while at the same time providing an opportunity to the smallholder farmers of the world. Hopes are high, but completely unrealistic. It is like trying to push a square peg into a round hole, according to a current thesis at Linköping University.

Bioenergy could replace fossil fuels and solve the looming energy crisis. Into the bargain, we will benefit from reduced greenhouse gas emissions. A further bonus could be that demand for biofuels gives a lift to smallholder farmers in poor countries, who would be able to diversify their production and sell an attractive product on the international market. In short, a win-win-win situation is being portrayed.

And not by just anyone, but by three highly influential international organisations:

• Food and Agriculture Organization of the United Nations (FAO)
• Intergovernmental Panel on Climate Change (IPCC)
• International Energy Agency (IEA)

Magdalena Kuchler, recently awarded her Ph.D. at the Centre for Water and Environmental Studies at Linköping University (LiU), investigated the thinking of these three organisations concerning bioenergy during the period 1990 -- 2010.

The question of the future of bioenergy has a bearing on three areas: food, climate and energy; she therefore chose these particular organisations for her investigation.

Her conclusion is that the high hopes for bioenergy will not be realised, at least not under the current economic system that demands that production be as cheap as possible. Here the three organisations end up in contradictions and a dilemma they are not able to resolve.

"The production of biofuels has to fit in with a market economy, which is completely allied to economic growth and the accumulation of capital," she writes.

The result is monocultures with mechanised production. Changed land use leads to increased greenhouse emissions that eat into the reductions that biofuels ought to provide. Highly mechanised production creates an increased dependency on fossil fuels rather than the opposite.

Read more at Science Daily

Dead Stars Could Be the Future of Spacecraft Navigation

Scientists at the National Physical Laboratory (NPL) and the University of Leicester have been commissioned by the European Space Agency (ESA) to investigate the feasibility of using dead stars to navigate spacecraft in deep space. The findings of the research will advise ESA strategy and if feasible this technique may in future revolutionise the way spacecraft navigate in the outer Solar System and beyond.

Spacecraft navigation currently relies on radio transmissions between a distant craft and a network of ground-stations on Earth. This means that the craft has to wait for an instruction from Earth to guide it through space and with the large distances involved this could take hours, days or even longer. This time delay affects a spacecraft's ability to react rapidly according to its location. Furthermore, the ground infrastructure is increasingly difficult and expensive to maintain due to the size of the radio antennas.

Scientists at NPL and the University of Leicester are exploring the use of X-rays from dead stars, called pulsars, to allow spacecraft to navigate autonomously. Pulsars are highly compact and rapidly rotating neutron stars that emit intense electromagnetic radiation observed as pulses, similar to the rotating beam of light seen from a light house. In some cases these pulses can be highly regular, making them suitable sources for navigation using a technique similar to GPS.

"Using on-board X-ray detectors, spacecraft could measure the times of pulses received from pulsars to determine the position and motion of the craft. The University of Leicester will use their experience in X-ray astronomy to come-up with potential designs of the device and NPL will develop timing and navigation algorithms to determine the potential accuracy of this technique. Funding received from ESA will allow us to investigate the feasibility of using these dead stars and the potential navigation performance that could be derived," says Setnam Shemar, leading the project on behalf of NPL's Time and Frequency Team.

The traditional form of ground-based space navigation can only support a limited number of spacecraft as only one set of measurements can be processed at any one time. If feasible, this new technique could allow a greater number of complex space missions to take place simultaneously in deep space as craft become capable of navigating themselves.

Read more at Science Daily

In Einstein's Math: Faster-Than-Light Travel?

Although Einstein's theories suggest nothing can move faster than the speed of light, two scientists have extended his equations to show what would happen if faster-than-light travel were possible.

Despite an apparent prohibition on such travel by Einstein's theory of special relativity, the scientists said the theory actually lends itself easily to a description of velocities that exceed the speed of light.

"We started thinking about it, and we think this is a very natural extension of Einstein's equations," said applied mathematician James Hill, who co-authored the new paper with his University of Adelaide, Australia, colleague Barry Cox. The paper was published Oct. 3 in the journal Proceedings of the Royal Society A: Mathematical and Physical Sciences.

Special relativity, proposed by Albert Einstein in 1905, showed how concepts like speed are all relative: A moving observer will measure the speed of an object to be different than a stationary observer will. Furthermore, relativity revealed the concept of time dilation, which says that the faster you go, the more time seems to slow down. Thus, the crew of a speeding spaceship might perceive their trip to another planet to take two weeks, while people left behind on Earth would observe their passage taking 20 years.

Yet special relativity breaks down if two people's relative velocity, the difference between their respective speeds, approaches the speed of light. Now, Hill and Cox have extended the theory to accommodate an infinite relative velocity. (Top 10 Implications of Faster-Than-Light Neutrinos)

Interestingly, neither the original Einstein equations, nor the new, extended theory can describe massive objects moving at the speed of light itself. Here, both sets of equations break down into mathematical singularities, where physical properties can't be defined.

"The actual business of going through the speed of light is not defined," Hill told LiveScience. "The theory we've come up with is simply for velocities greater than the speed of light."

In effect, the singularity divides the universe into two: a world where everything moves slower than the speed of light, and a world where everything moves faster. The laws of physics in these two realms could turn out to be quite different.

In some ways, the hidden world beyond the speed of light looks to be a strange one indeed. Hill and Cox's equations suggest, for example, that as a spaceship traveling at super-light speeds accelerated faster and faster, it would lose more and more mass, until at infinite velocity, its mass became zero.

"It's very suggestive that the whole game is different once you go faster than light," Hill said.

Read more at Discovery News

Language Learning Makes the Brain Grow, Swedish Study Suggests

At the Swedish Armed Forces Interpreter Academy, young recruits learn a new language at a very fast pace. By measuring their brains before and after the language training, a group of researchers has had an almost unique opportunity to observe what happens to the brain when we learn a new language in a short period of time.

At the Swedish Armed Forces Interpreter Academy in the city of Uppsala, young people with a flair for languages go from having no knowledge of a language such as Arabic, Russian or Dari to speaking it fluently in the space of 13 months. From morning to evening, weekdays and weekends, the recruits study at a pace unlike on any other language course.

As a control group, the researchers used medicine and cognitive science students at Umeå University -- students who also study hard, but not languages. Both groups were given MRI scans before and after a three-month period of intensive study. While the brain structure of the control group remained unchanged, specific parts of the brain of the language students grew. The parts that developed in size were the hippocampus, a deep-lying brain structure that is involved in learning new material and spatial navigation, and three areas in the cerebral cortex.

"We were surprised that different parts of the brain developed to different degrees depending on how well the students performed and how much effort they had had to put in to keep up with the course," says Johan Mårtensson, a researcher in psychology at Lund University, Sweden.

Students with greater growth in the hippocampus and areas of the cerebral cortex related to language learning (superior temporal gyrus) had better language skills than the other students. In students who had to put more effort into their learning, greater growth was seen in an area of the motor region of the cerebral cortex (middle frontal gyrus). The areas of the brain in which the changes take place are thus linked to how easy one finds it to learn a language and development varies according to performance.

Previous research from other groups has indicated that Alzheimer's disease has a later onset in bilingual or multilingual groups.

Read more at Science Daily

Skulls From Sacrificial Rituals Found in Temple

Archaeologists have unearthed gruesome evidence of brutal Aztec rituals by uncovering 50 skulls and over 250 jaw bones at the Templo Mayor in Tenochtitlan (modern Mexico City).

Found at one sacrificial stone below a ceremonial platform called the "cuauhxicalco," the human remains date back more than 500 years and represent the largest number of skulls ever found in one offering.

Used in rituals associated with the worship of Mictlantecuhtli, god of death, the skulls were unearthed in different locations: 45 appeared to have just been dumped on top of the stone, while the remaining five were buried under it.

Each of the five skulls had holes on both sides, suggesting they belonged to a tzompantli. This was a skull rack on which the crania of sacrificed people were hung and displayed near temples or at other locations.

"Some of the 45 skulls found on the sacrificial stone were manipulated with the intention of preparing skull-masks that were never finished," archaeologist Raul Barrera of Mexico's National Institute of Anthropology and History (INAH) said.

According to the archaeologist, the skulls belonged to women and men between 20 and 35 years old. Some could have been dug up from other sites and reburied.

Looking like a gray headstone, the 18-inch-high, 14 to 17-inch-long and 3-inch-thick sacrificial rock revealed new ways that the Aztecs used skulls in their rituals.

Read more at Discovery News

100-Million-Year-Old Spider Attack Found in Amber

Researchers have found trapped in amber a rare dinosaur-age scene of a spider attacking a wasp caught in its web.

The piece of amber, which contains 15 intact strands of spider silk, provides the first fossil evidence of such an assault, the researchers said. It was excavated in a Burmese mine and dates back to the Early Cretaceous, between 97 million and 110 million years ago.

"This juvenile spider was going to make a meal out of a tiny parasitic wasp, but never quite got to it," George Poinar, Jr., a zoology professor at Oregon State University, said in a statement.

"This was a male wasp that suddenly found itself trapped in a spider web. This was the wasp's worst nightmare, and it never ended. The wasp was watching the spider just as it was about to be attacked, when tree resin flowed over and captured both of them."

Poinar and Ron Buckley, an amber collector from Kentucky, described the find in a paper published in the October issue of the journal Historical Biology. They wrote that while there are examples of amber-trapped insects caught in webs, "there is no previous fossil record of a spider attacking its ensnared prey."

The amber chunk also contains the body of another male spider in the same web, which might make the fossil the oldest known evidence of social behavior in spiders, according to the authors.

Read more at Discovery News

Odd Maar Volcano Explosions Explained

The eruption of a so-called maar-diatreme volcano is short-lived but violent. Magma creeps up through a crack in the Earth's crust and mixes with water, setting off a series of explosions — as many as a few each hour for several weeks. When the action stops, a crater-topped, rock-filled fracture called a diatreme is left behind.

Now researchers are proposing a new way to think about how these structures are formed, which could help geologists predict eruptions and find new sources of diamonds.

"Previously it was thought that those explosions started at very shallow levels and got progressively deeper," geologist Greg Valentine, a professor at the University at Buffalo in New York, told LiveScience.

 This old model seemed to explain the shape of a diatreme, which sits like an inverted cone beneath a shallow maar, or crater. But that model didn't match with what geologists were finding at volcanic sites, Valentine said.

If the explosions started at shallow levels and moved deeper, shallow rocks would be spewed from the mouth of the volcano first and the deeper rock deposits would pile up on top. At maar sites, however, scientists were finding deep rock fragments mixed mostly with shallow fragments, indicating that explosions occur at essentially every depth throughout the episode. (50 Amazing Volcano Facts)

Valentine and James White, an associate professor at the University of Otago in New Zealand, created a new model to account for the apparently more jumbled order of explosions. Their model, published online Sept. 18 by the journal Geology, also shows that individual explosions are relatively small, and shallow explosions are more likely than deep explosions to cause eruptions.

Revised model for diatreme growth, with explosive molten fuel– coolant interactions (MFCI) taking place over a range of depths, breaking up rock where the explosions take place, but being most effective at shallow depths. After the initial blasts, explosions continue to occur throughout the depth range, but widen the upper part much more rapidly to produce the typical flared diatreme structure.

The last known maar-diatreme eruption occurred in 1977 in Alaska's remote Aleutian Range, forming two vents known as the Ukinrek Maars. The threats associated with these volcanoes tend to be localized, but they can still be significant, Valentine said.

"These volcanoes can send ash deposits into populated areas. They could easily produce the same effects that the one in Iceland did when it disrupted air travel, so what we're trying to do is understand the way they behave," he explained in a statement.

Read more at Discovery News

Whether We Like Someone Affects How Our Brain Processes Movement

Hate the Lakers? Do the Celtics make you want to hurl? Whether you like someone can affect how your brain processes their actions, according to new research from the Brain and Creativity Institute at the USC Dornsife College of Letters, Arts and Sciences.

Most of the time, watching someone else move causes a "mirroring" effect -- that is, the parts of our brains responsible for motor skills are activated by watching someone else in action.

But a study by USC researchers appearing October 5 in PLOS ONE shows that whether you like the person you're watching can actually have an effect on brain activity related to motor actions and lead to "differential processing" -- for example, thinking the person you dislike is moving more slowly than they actually are.

"We address the basic question of whether social factors influence our perception of simple actions," said Lisa Aziz-Zadeh, assistant professor with the Brain and Creativity Institute and the Division of Occupational Science. "These results indicate that an abstract sense of group membership, and not only differences in physical appearance, can affect basic sensory-motor processing."

Past research has shown that race or physical similarity can influence brain processes, and we tend to have more empathy for people who look more like us.

In this study, the researchers controlled for race, age and gender, but they introduced a backstory that primed participants to dislike some of the people they were observing: Half were presented as neo-Nazis, and half were presented as likable and open-minded. All study participants recruited for the study were Jewish males.

The researchers found that when people viewed someone they disliked, a part of their brain that was otherwise activated in "mirroring" -- the right ventral premotor cortex -- had a different pattern of activity for the disliked individuals as compared to the liked individuals.

Importantly, the effect was specific to watching the other person move. There was no difference in brain activity in the motor region when participants simply watched still videos of the people they liked or disliked.

Read more at Science Daily

Sleeping Brain Behaves as If It's Remembering Something

UCLA researchers have for the first time measured the activity of a brain region known to be involved in learning, memory and Alzheimer's disease during sleep. They discovered that this part of the brain behaves as if it's remembering something, even under anesthesia, a finding that counters conventional theories about memory consolidation during sleep.

The research team simultaneously measured the activity of single neurons from multiple parts of the brain involved in memory formation. The technique allowed them to determine which brain region was activating other areas of the brain and how that activation was spreading, said study senior author Mayank R. Mehta, a professor of neurophysics in UCLA's departments of neurology, neurobiology, physics and astronomy.

In particular, Mehta and his team looked at three connected brain regions in mice -- the new brain or the neocortex, the old brain or the hippocampus, and the entorhinal cortex, an intermediate brain that connects the new and the old brains. While previous studies have suggested that the dialogue between the old and the new brain during sleep was critical for memory formation, researchers had not investigated the contribution of the entorhinal cortex to this conversation, which turned out to be a game changer, Mehta said. His team found that the entorhinal cortex showed what is called persistent activity, which is thought to mediate working memory during waking life, for example when people pay close attention to remember things temporarily, such as recalling a phone number or following directions.

"The big surprise here is that this kind of persistent activity is happening during sleep, pretty much all the time." Mehta said. "These results are entirely novel and surprising. In fact, this working memory-like persistent activity occurred in the entorhinal cortex even under anesthesia."

The study appears Oct. 7, 2012 in the early online edition of the journal Nature Neuroscience.

The findings are important, Mehta said, because humans spend one-third of their lives sleeping and a lack of sleep results in adverse effects on health, including learning and memory problems.

It had been shown previously that the neocortex and the hippocampus "talk" to each other during sleep, and it is believed that this conversation plays a critical role in establishing memories, or memory consolidation. However, no one was able to interpret the conversation.

"When you go to sleep, you can make the room dark and quiet and although there is no sensory input, the brain is still very active," Mehta said. "We wanted to know why this was happening and what different parts of the brain were saying to each other."

Mehta and his team developed an extremely sensitive monitoring system that allowed them to follow the activities of neurons from each of three targeted portions of the brain simultaneously, including the activity of a single neuron. This allowed them to decipher the precise communications, even when the neurons were seemingly quiet. They then developed a sophisticated mathematical analysis to decipher the complex conversation.

During sleep, the neocortex goes into a slow wave pattern for about 90 percent of that time. During this period, its activity slowly fluctuates between active and inactive states about once every second. Mehta and his team focused on the entorhinal cortex, which has many parts.

The outer part of the entorhinal cortex mirrored the neocortical activity. However, the inner part behaved differently. When the neocortex became inactive, the neurons in the inner entorhinal cortex persisted in the active state, as if they were remembering something the neocortex had recently "said," a phenomenon called spontaneous persistent activity. Further, they found that when the inner part of the entorhinal cortex became spontaneously persistent, it prompted the hippocampus neurons to become very active. On the other hand, when the neocortex was active, the hippocampus became quieter. This data provided a clear interpretation of the conversation.

"During sleep the three parts of the brain are talking to each other in a very complex way," he said. "The entorhinal neurons showed persistent activity, behaving as if they were remembering something even under anesthesia when the mice could not feel or smell or hear anything. Remarkably, this persistent activity sometimes lasted for more than a minute, a huge timescale in brain activity, which generally changes on a scale of one thousandth of a second."

The findings challenge theories of brain communication during sleep, in which the hippocampus is expected to talk to, or drive, the neocortex. Mehta's findings instead indicate that there is a third key actor in this complex dialogue, the entorhinal cortex, and that the neocortex is driving the entorhinal cortex, which in turn behaves as if it is remembering something. That, in turn, drives the hippocampus, while other activity patterns shut it down.

"This is a whole new way of thinking about memory consolidation theory. We found there is a new player involved in this process and it's having an enormous impact," Mehta said. "And what that third player is doing is being driven by the neocortex, not the hippocampus. This suggests that whatever is happening during sleep is not happening the way we thought it was. There are more players involved so the dialogue is far more complex, and the direction of the communication is the opposite of what was thought."

Mehta theorizes that this process occurs during sleep as a way to unclutter memories and delete information that was processed during the day but is irrelevant. This results in the important memories becoming more salient and readily accessible. Notably, Alzheimer's disease starts in the entorhinal cortex and patients have impaired sleep, so Mehta's findings may have implications in that arena.

For this study, Mehta teamed with Thomas Hahn and Sven Berberich of Heidelberg University in Germany and the Max Planck Institute for Medical Research and James McFarland of Brown University and the UCLA Department of Physics. Going forward, the team will further study this brain activity to uncover the mechanisms behind it and determine if it influences subsequent behavioral performance.

Read more at Science Daily