Scientists have long tried to tease out the secrets of what makes us human by comparing human behavior to how other species behave, such as chimpanzees.

But now a research team hopes to get at the question another way - by studying the DNA of Neanderthals, early hominids that were similar to humans, said Richard "Ed" Green, a computational biologist at the University of California at Santa Cruz.

"What is clear is that our closest extinct relative is the Neanderthal," Green told an overflow crowd of University of Georgia professors and students in a Coverdell Hall lecture room Tuesday. "They are way more similar to humans than anything else."

Green is part of the research team, led by Svante Paabo of Germany's Max Planck Institute for Evolutionary Anthropology, that partially sequenced the genome of Neanderthals using DNA from bones buried in a Croatian cave nearly 40,000 years ago.

Recently, archaeologists found prehistoric hats of human beings who lived 4,600 years ago from an ancient tomb site at Tongliao City of Inner Mongolia.

Experts said it was the first time this kind of hats, which were made from bones, have been found in the same period of prehistoric culture.

As of now, archaeologists have found and cleared near 400 ancient tombs dating back 4,500 years ago around the site, and more than 1,500 objects of pottery, jade stone, horn and clam shell were excavated.

The newly-found bone hats were tightly cramped on dead bodies' heads and had the obvious shape of hats. After inspection, every such hat was made from 15 or 16 animal bones, and the length and radian of those are all very delicate.

It's been more than two decades since we Earthlings got word that a star in the Large Magellanic Cloud had blown itself to smithereens.

Supernova 1987A peaked at 3rd magnitude, making it a snap to spot by eye. But, with its declination of -69°, the blast was invisible to virtually everyone north of the equator. I'm jealous of my southern astro-friends because I never got to see it. (In fact, I wonder how the popular perception of and appreciation for astronomy might be different had this event been in view from northern skies - a topic for another day!)

Scientists decode words from brain signals.

In an early step toward letting severely paralyzed people speak with their thoughts, University of Utah researchers translated brain signals into words using two grids of 16 microelectrodes implanted beneath the skull but atop the brain.

"We have been able to decode spoken words using only signals from the brain with a device that has promise for long-term use in paralyzed patients who cannot now speak," says Bradley Greger, an assistant professor of bioengineering.

Because the method needs much more improvement and involves placing electrodes on the brain, he expects it will be a few years before clinical trials on paralyzed people who cannot speak due to so-called "locked-in syndrome."

The Journal of Neural Engineering's September issue is publishing Greger's study showing the feasibility of translating brain signals into computer-spoken words.

It's a big skull. No, wait, it's two people under an arch. Hold on, it's a skull again. Two very different images can be perceived in the trick picture Blossom and Decay (see left). Now we are one step closer to working out how the brain spontaneously flips between such views, with the discovery of what may be the relevant brain region.

The precise neural mechanism that provokes the brain to switch its view of a scene is unknown, but it is thought to play a major role in perception by acting as a sort of reality check, says Ryota Kanai of University College London. "We need a trigger to prompt possible different interpretations so that we don't get stuck with a potentially incorrect interpretation of the world."

To find out which part of the brain might be involved, Kanai and colleagues asked 52 volunteers to watch a video of a revolving sphere and press a button when the rotation of the sphere appeared to change direction. Crucially, the sphere was not changing direction; it could simply be perceived to be rotating in either direction. How long each rotation-direction was perceived for was recorded and an average "switch rate" assigned to each of the volunteers.

The team then used structural magnetic resonance imaging to search for active brain regions during this task. This pointed to the superior parietal lobes (SPL), two areas towards the back of the head known to control attention and process three-dimensional images. People whose cortex was thicker and better connected in this region had faster switch rates.

In humans, the cerebral cortex, the tissue like outermost layer of the brain, is thought to play a critical role in creative and analytical thinking.

But just how this portion of the brain evolved has remained a mystery.

Now researchers report that something resembling a cerebral cortex exists in the marine ragworm, a small creature with ancient roots that has not changed in hundreds of millions of years. The findings appear in the journal Cell.

"You can say that the topography is so similar that the human and worm must come from a common ancestor," said Detlev Arendt, a researcher at the European Molecular Biology Laboratory and one of the study's authors.

To conduct their study, Dr. Arendt and his colleagues used a technique called cellular profiling to determine what genes were turned on and off in the cells of the ragworm's brain. This sort of profiling provides a molecular footprint for each cell.

To the untrained eye, all evidence here in the heart of the Amazon signals virgin forest, untouched by man for time immemorial - from the ubiquitous fruit palms to the cry of howler monkeys, from the air thick with mosquitoes to the unruly tangle of jungle vines.

Archaeologists, many of them Americans, say the opposite is true: This patch of forest, and many others across the Amazon, was instead home to an advanced, even spectacular civilization that managed the forest and enriched infertile soil to feed thousands.

The findings are discrediting a once-bedrock theory of archaeology that long held that the Amazon, unlike much of the Americas, was a historical black hole, its environment too hostile and its earth too poor to have ever sustained big, sedentary societies. Only small and primitive hunter-gatherer tribes, the assumption went, could ever have eked out a living in an unforgiving environment.

But scientists now believe that instead of stone-age tribes, like the groups that occasionally emerge from the forest today, the Indians who inhabited the Amazon centuries ago numbered as many as 20 million, far more people than live here today.

Identities of the mysterious women carved into the Cambodian temple could finally be revealed. Andrew Buncombe reports

Amid the splendour of the 12th-century temple at Angkor Wat, they stand and stare like silent sentinels, sensuous rather than erotic, carved with elegance and care. But exactly who are these 1,786 mysterious women and why, more than a century after Cambodia's famed Hindu temple was rediscovered by Western archaeologists, did it take the efforts of an amateur researcher from Florida to push experts into trying to resolve the puzzle?

Though Kent Davis had lived in South-east Asia during the 1990s, he did not have an opportunity to see Angkor Wat until 2005. Like most visitors to the huge complex in the centre of the Cambodia, for many years cut off from the outside world because of the presence of the Khmer Rouge, he was mesmerised by the experience.

But he was also left with a flurry of questions. "I went to Angkor as a tourist and I was startled when I got there to notice these women," said Mr Davis, 54, a publisher and writer who now lives near Tampa, Florida. "I was not prepared for it. The human element of them struck me and I wanted to know who they were. I asked one of the guides and he said they were there to serve the king after he went to heaven."

Mr Davis's interest was tweaked, so he wanted to know more. He vowed he would return to the US and investigate. Yet when he got home he found there was essentially nothing written about these women, who appear throughout the temple complex in full body carvings.

Indeed, the only study of the female carvings he could find had been made in the early 20th century by the daughter of Frenchman Henri Marchal, then the curator of the temple site. Frustrated but intrigued, he decided he would find out for himself. Five years and several trips to Angkor later, Mr Davis has slowly begun to get some answers.

Hubble Space Telescope observations of the aftermath of a giant star explosion are offering a new glimpse into the events that follow the collapse of a massive dying star.

This well-known supernova remnant in a neighboring galaxy has been studied for more than 10 years, but the recent observations could glean new knowledge of how such stellar debris helps shape the evolution of galaxies.

The new study, led by Kevin France, a research associate at the Center for Astrophysics and Space Astronomy at the University of Colorado in Boulder, targeted the remnants of star SN1987A, which was first discovered in 1987.

Stars like this that have at least eight times the mass of our sun are considered "massive" stars, France said, and they speed toward death very quickly. Unable to support their weight any longer, these stars end their lives by collapsing in spectacular supernova explosions.

For the first time in the world, Iranian scientists have succeeded in discovering the gene responsible for a common type of blindness, prevalent in North Eastern parts of the country.

Latest figures have revealed that one in every family living in Esfarayen, in North Khorasan province, are blind, indicating that the blindness gene runs in these families. Scientists and officials had long considered climate and environmental factors as the main cause contributing to the condition.

According to Normohammad Ghiasvand, a genetic professor in Shahid Beheshti University of Medical Sciences, the high prevalence of a certain gene accounts for the considerably high number of blind people in this area.