Oct 22, 2011

First North American Hunters 1,000 Years Earlier Than Previously Thought, Speared Mastodon Fossil Shows

A new and astonishing chapter has been added to North American prehistory in regards to the first hunters and their hunt for the now extinct giant mammoth-like creatures -- the mastodons. Professor Eske Willerslev's team from the Centre for GeoGenetics, University of Copenhagen, has in collaboration with Michael Waters' team at the Center for the Study of the First Americans, University of Texas A&M, shown that the hunt for large mammals occurred at least 1,000 years before previously assumed.

This new study concludes that the first-known hunters in North America can now be dated back at least 14,000 years.

"I am sure that especially the Native Americans are pleased with the results of the study. It is further proof that humans have been present in North America for longer than previously believed. The "Clovis First" theory, which many scientists swore to just a few years back, has finally been buried with the conclusions of this study," says Professor Eske Willerslev, director of the Centre for GeoGenetics at the Natural History Museum of Denmark, University of Copenhagen.

Spearhead found in mastodon

It is the finding and analysis of a tip from a human-made projectile point (spearhead) gathered from the remains of a mastodon that is behind the rewriting of North American prehistory. The spearhead, which itself was carved out from a mastodon-bone, was found at the Manis site in the state of Washington when archaeologists excavated a mastodon in the late 1970s.

However, 30 years would pass before a team of researchers was able to put a date on the spearhead and establish the identity of both the bone and the spearhead that had been embedded into the rib of the defeated mastodon. This was done through, amongst other things, DNA analysis, protein sequencing, advanced computer technology, Carbon-14 dating as well as comparisons with other mastodon findings in North America, for instance in the state of Wisconsin.

Clovis culture challenged

The first traces of the hunt for mastodons in North America have previously been attributed the so-called Clovis culture. Clovis culture dates back approximately 13,000 years and is viewed as a type of common culture ancestral for all Native American tribes in North America.

"Our research now shows that other hunters were present at least 1,000 years prior to the Clovis culture. Therefore, it was not a sudden war or a quick slaughtering of the mastodons by the Clovis culture, which made the species disappear. We can now conclude that the hunt for the animals stretched out over a much longer period of time. At this time, however, we do not know if it was the man-made hunt for the mastodons, mammoths and other large animals from the so-called mega-fauna, which caused them to become extinct and disappear. Maybe the reason was something complete different, for instance the climate," states Professor Eske Willerslev.

Read more at Science Daily

Dark energy: the universe is destined to become a very cold and lonely place

Brian Schmidt of the Australian National University in Canberra was recently named as a joint winner of the 2011 Nobel Prize in Physics. The formal citation reads: "For the discovery of the accelerating expansion of the universe through observations of distant supernovae". Prof Schmidt and his team’s work on the expansion of the universe fundamentally changed astrophysics - it opened up a whole new area of science and introduced the world to the concept of dark energy. However, the team was looking for, and expecting, the complete opposite.

“Just like a ball you through up in the air, we expected the universe to crash back down and give us the Big Bang in reverse, which we like to call the Gnab Gib", he says. “But after about 3 years, the data were coming in and it showed that the expansion of the universe was not slowing down at all but was speeding up. That was a real crazy thing to be confronted with. It didn’t make a lot of sense. It seemed just impossible. It was a pretty scary time when we first saw that result.”

Like the recent faster-than-light neutrinos story, the team were faced with a result that must be wrong. After looking for problems with the experiment and checking their results again and again, no mistakes could be found. The team decided to release the data.

“I was expecting a reaction very similar to the faster than light neutrinos announcement. Some people were sceptical, and I don’t blame them for being sceptical. I was sceptical when we released it – I just could not make the result go away. It was just crazy that somehow we had missed 75 per cent of the universe. And this 75 per cent of the universe caused gravity to work in reverse.”

This missing 75 per cent, so-called dark energy, is accelerating the expansion of space. Physicists don’t know what it is – as Prof Schmidt says: “when astronomers discover something they can’t see, they just call it ‘dark x’; in this case x was energy”. The accelerating expansion allows cosmologists to make predictions about the future of the universe.

Prof Schmidt continues: “Right now, when light travels through the cosmos to us it has to compete with the expansion of the universe to get to us. Light takes a long time to get to us, but it gets to us. In the future because the universe is speeding up, it is expanding faster and faster over time, at some point the universe will be so stretched that the light from distant galaxies will never reach us.

“The entire universe that is not gravitationally bound to us right now will eventually be stretched beyond our ability to see it. We will look out to a universe on which you cannot do cosmology because there is nothing to see. It will be a very empty universe.

Read more at The Telegraph

Oct 21, 2011

New Evidence for the Oldest Oxygen-Breathing Life On Land

New University of Alberta research shows the first evidence that the first oxygen-breathing bacteria occupied and thrived on land 100 million years earlier than previously thought. The researchers show that the most primitive form of aerobic-respiring life on land came into existence 2.48 billion years ago.

The research team, led by U of A geomicrobiologist Kurt Konhauser, made their find by investigating a link between atmospheric oxygen levels and rising concentrations of chromium in the rock of ancient seabeds.

"We suggest that the jump in chromium levels was triggered by the oxidation of the mineral pyrite (fool's gold) on land," said Konhauser.

Pyrite oxidation is a simple chemical process driven by two things: bacteria and oxygen. The researchers say this proves that oxygen levels in Earth's atmosphere increased dramatically during that time.

"Aerobic bacteria broke down the pyrite, which released acid that dissolved rocks and soils into a cocktail of metals, including chromium," says Konhauser. "The minerals were then carried to the oceans by the run-off of rain water.

"Our examination of the ancient seabed data shows the chromium levels increased significantly 2.48 billion years ago," said Konhauser. "This gives us a new date for the Great Oxidation Event, the time when the atmosphere first had oxygen."

The rising levels of atmospheric oxygen fostered the development of new bacteria species, and Konhauser says that, following the evolutionary path back to that first oxygen-breathing life form on land, our ancestors started off in a pool of highly acidic water.

The researchers say the modern analogue for that first primitive oxygen-dependent life form on Earth is still with us.

"The same bacterial life forms are alive and well today, living off pyrite and settling in the highly acidic waste waters of mining sites the world over," said Konhauser.

Read more at Science Daily

Real-Life 'Paranormal Activity:' Are Ghosts Real?

A still from "Paranormal Activity 3." Credit: Paramount Picutures

The new horror film "Paranormal Activity 3" features another set of amateur ghost hunters trying to document evidence of paranormal activity through the use of home video cameras.

The twitchy, grainy video images of demons and ghosts have scared up hundreds of millions of dollars in box office gold in two previous installments of the low-budget franchise.

It's all good fun for spooky cinematic scares. But what about in the real world?

Between one-third and one-half of Americans believe in ghosts, and that belief motivates many to look for evidence of the paranormal. Researcher Sharon Hill of the Doubtful Newsblog counted about 2,000 active amateur ghost hunting groups in America. Almost all of them are patterned directly after the hit SyFy TV show Ghost Hunters, which is now in its eighth season of failing to find good evidence of ghosts.

Despite the efforts of thousands of real-life ghost hunters over the past decade, the evidence for ghosts has not improved. Typically the types of evidence offered for the paranormal falls into a few categories:

1) Personal Experiences

Ghost hunters often report personal feelings and experiences like, "I felt we were being watched," or "I felt like something didn't want us there." They also describe, for example, getting goose bumps upon entering a room, or panicking at some unseen presence. There's nothing wrong with personal experiences, but they are not evidence of anything other than that people scare themselves in dark, spooky places.

2) Orbs

Many ghost hunters and books on hauntings claim that ghosts can be photographed, and appear as round or oval white shapes called orbs. Many things can create orbs, including insects, dust, and flash reflections. Orbs may seem otherworldly because they appear only in photographs and are usually invisible to the naked eye. To those unaware of the real explanation they can be spooky, but there is nothing paranormal about them.

3) Ghost Equipment Results

Ghost investigators often use unscientific and unproven equipment and techniques in their search for spirits. Some use psychics to try and communicate with ghosts. Others use dowsing rods, which have never been scientifically proven to find anything (including water and restless spirits). Still others, striving for some semblance of science, use high-tech devices such as electromagnetic field (EMF) detectors and infrared cameras.

These devices are commonly sold as ghost hunting gear, but there is no logical or scientific reason to use this equipment when looking for the paranormal. EMF detectors measure electromagnetic fields, not ghosts; infrared cameras reveal the infrared spectrum, not ghosts. There is no evidence that ghosts have anything to do with electromagnetic fields, infrared images, ions, temperature drops, etc.

4) Electronic Voice Phenomena (EVP)

Most ghost hunters, including the Ghost Hunters team, use handheld voice recorders in an attempt to capture a supposed ghost voice, or EVP. Often the investigator holds it while standing in the middle of a room and addressing the supposed spirit, or while walking around. They later go back and review the recordings at high volume, listening for any faint murmurs, sounds, or noises, which they may interpret as ghost voices. For example a ghost hunter may ask out loud, "If there's a spirit here, what's your name?"

Often they will get no answer at all; other times, if they wait long enough they'll hear some random sound that could be interpreted as a faint, mumbled name: "Mary." (Or maybe Terry, Kerry, Larry, or Barry—never mind the fact that, as disembodied spirits, ghosts presumably do not have vocal cords, a tongue, or a mouth that would allow them to speak.)

The problem is that microphones are very sensitive, and may record anything from someone whispering in the next room, to wind blowing, ordinary random sounds from the environment, or even sounds from the ghost hunters themselves. There's no mystery about what causes EVPs, and it has nothing to do with ghosts. EVPs are created by a well-understood psychological process called apophenia, which causes people to "hear" distinct sounds in random white noise patterns such as the background static in an audio recording (like hearing the doorbell or the telephone while one is in the shower).

The same way that the human brain allows us to "recognize" random patterns like faces in clouds, our brains allow us to hear words and phrases in random sounds that aren't really there. In fact EVPs can be easily heard and induced in laboratory experiments; no ghosts required.

Read more at Discovery News

Couple Held Hands for 1,500 Years

The skeletal remains of a Roman-era couple reveal the pair has been holding hands for 1,500 years.

Italian archaeologists say the man and woman were buried at the same time between the 5th and 6th century A.D. in central-northern Italy. Wearing a bronze ring, the woman is positioned so she appears to be gazing at her male partner.

"We believe that they were originally buried with their faces staring into each other. The position of the man's vertebrae suggests that his head rolled after death," Donato Labate, the director of the excavation at the archaeological superintendency of Emilia-Romagna, told Discovery News.

The tender discovery was made during ordinary construction work in Modena and was announced this week. Labate explained the dig revealed three layers of scientific interest.

The deeper layer, some 23 feet below the surface, contained the remains of Roman-era structures, including a calcara where mortar was produced. The ruins belonged to the suburbs of Modena, then called Mutina.

"A middle layer, at a depth of about 10 feet, featured 11 burials, while a third stratification on top of the necropolis, revealed seven empty tombs," Labate said.

Excavated by archaeologist Licia Diamanti, the skeleton couple belonged to the 11 tomb necropolis. According to Labate, the simple fossa (trench) tombs suggest that the people buried there were not particularly rich.

"They were possibly the inhabitants of a farm," Labate said.

The area was subjected to several floods from the nearby river Tiepido -- which may have caused the male skeleton's skull to roll away from the female skeleton after burial. The necropolis was covered by alluvial deposits, and on top of them, another seven tombs were built.

"These burials were empty. Most likely, they were covered by another flood just after their construction. We think it was a catastrophic flood which occurred in 589, as reported by the historian Paul the Deacon," Labate said.

The two skeletons, which are poorly preserved, will be now studied by Giorgio Gruppioni, an anthropologist at the University of Bologna. The research includes establishing the couple's age, their relationship and the possible cause of death.

"In antiquity, it is not surprising to learn of spouses or members of a family dying at the same time: whenever epidemics such as the Black Plague ravaged Europe, one member of the family would often die while the family was trying to bury another member," Kristina Killgrove, a biological anthropologist at the University of North Carolina, told Discovery News.

Read more at Discovery News

Glow-In-The-Dark Surf Explained

Red tide at night is a sailor's delight. Red tide in morning, sailors take warning. That's not exactly how the mariner rhyme goes, but it should. Often along the California coastline as well as elsewhere in places where conditions encourage plankton blooms from single-celled dinoflagellates the sea turns brownish-red during the day, but at night becomes an ocean of bioluminescent beauty.

Scientists have long known that this type of bioluminescence occurs when billions of dinoflagellates get jostled. In 2005, the Naval Research Laboratory identified the first satellite image of bioluminescence spanning hundreds of miles - confirming ancient mariner lore of sailing on glowing seas for nights at time.

But a scientific explanation for how the tiny plankton glow in the dark has remained elusive.

Until now.

The key to the dinoflagellate process is the existence of voltage-gated or voltage-sensitive proton channels. These channels form in the membranes that separate one compartment of a cell from another, but it takes certain chemicals or electrical signals to open them. Researchers long assumed that these channels probably existed in dinoflagellates, but this week biologists reported in the Proceedings of the National Academy of Sciences successful identification and testing of dinoflagellate genes similar to the genes for voltage-sensitive proton channels known previously in humans, mice and sea squirts.

Read more and see video at Discovery News

Oct 20, 2011

Young Human-Specific Genes Correlated With Brain Evolution

Young genes that appeared since the primate branch split from other mammal species are expressed in unique structures of the developing human brain, a new analysis finds. The correlation suggests that scientists studying the evolution of the human brain should look to genes considered recent by evolutionary standards and early stages of brain development.

"There is a correlation between the new gene origination and the evolution of the brain," said Manyuan Long, PhD, Professor of Ecology & Evolution at the University of Chicago and senior author of the study in PLoS Biology. "We're not talking about one or two genes, we're talking about many genes. This is a process that is continually moving and changing our brain."

Scientists have long sought to solve how the brain evolved to have the anatomical features and functional ability that separate humans from their primate ancestors. With the completion of the Human Genome Project in 2003 and the growing availability of genome sequences for primates and other species, researchers have looked to genetics for answers on brain evolution.

From these studies, many scientists have hypothesized that differential regulation of conserved genes shared across species, rather than the arrival of new species-specific protein-encoding genes, was responsible for the dramatically different human brain. But in a 2010 study, Long's laboratory discovered that the younger species-specific genes could be just as important as older conserved genes to an organism's development.

For the PLoS Biology paper, researchers merged a database of gene age with transcription data from humans and mice to look for when and where young genes specific to each species were expressed.

The researchers found that a higher percentage of primate-specific young genes were expressed in the brain compared to mouse-specific young genes. Human-specific young genes also were more likely to be expressed in the recently expanded human brain structures, such as the neocortex and prefrontal cortex.

"Newer genes are found in newer parts of the human brain," said Yong Zhang, PhD, postdoctoral researcher and first author on the study. "We know the brain is the most remarkable difference between humans and other mammals and primates. These new genes are a candidate for future studies, as they are more likely to underlie this difference."

The timing of when the young human-specific genes are expressed in the brain also intrigued the researchers. Inspired by an ultrasound appointment with his pregnant wife, Zhang calculated when young genes were expressed in the human brain, discovering that they were more likely to appear during fetal or infant development.

The early activity of these genes suggests scientists should be looking at earlier developmental stages for genetic activity that ultimately shapes the complexity of the human brain.

"What's really surprising is that the evolutionary newest genes on the block act early," said co-author Patrick Landback, a graduate student in Long's laboratory. "The primate-specific genes act before birth, even when a human embryo doesn't look very different from a mouse embryo. But the actual differences are laid out early."

Thus far, researchers comparing adult brains between species have focused on regulatory differences as the primary driver of evolutionary changes. But the new research suggests that new genes with novel functions may have also played an important, previously overlooked role in the evolution of the human brain.

"Traditionally, people don't believe that a new protein or a new gene can play any role in an important process. Most people pay attention to only the regulation of genes," Long said. "But out of a total of about 1,300 new genes, only 13 percent were involved in new regulation. The rest, some 1,100 genes, are new genes that bring a whole new type of function."

Future research will look at the function of these genes and the role they may have played in building the unique human brain.

"People tend to study genes that are old functions present in organisms, and not those from new genes," said Maria Vibranovski, PhD, study co-author and research assistant professor. "This work will open a window such that people will start working in these new genes to try to figure out what exactly the functions are."

For now, the authors stress that their finding is only a correlation between the appearance of young human-specific genes and the evolutionary appearance of advanced brain structures. More data will need to be collected on the timing and location of gene expression in non-human primates to determine precisely which new genes and biological functions contributed to the evolution of the human brain.

Read more at Science Daily

Piecing Together the Priceless 'Cairo Genizah'

A well-known collection of historical texts, the Cairo Genizah is one of the most valuable sources of primary documents for medieval historians and religious scholars. The 350,000 fragments found in the Genizah include not only religious texts, but also social and commercial documents, dating from the 9th to 19th century. But the collection is scattered among 70 institutions worldwide, including libraries in Cambridge, Jerusalem, and New York City, and scholars are hampered by both the wide dispersal of the collection as well as their fragmentary condition.

Now researchers at Tel Aviv University are working to piece together this illuminating collection, bringing the pages of the texts back together for the first time in centuries. The results are being made available to scholars around the world through a website. Profs. Lior Wolf and Nachum Dershowitz of TAU's Blavatnik School of Computer Science have developed sophisticated software, based on facial recognition technology, that can identify digitized Genizah fragments thought to be a part of the same work and make editorial "joins."

Their technology was developed in close collaboration with the Friedberg Genizah Project, a non-profit organization that seeks to facilitate Genizah research by tracking, cataloguing, and digitizing all the fragments of this collection. The research was presented at the 2011 IEEE International Conference on Computer Vision.

Restoring history

Under Jewish law, religious texts cannot simply be thrown away once they're "worn out" from overuse. While many texts were buried, many synagogues also operated genizahs, or storerooms, to store disused holy texts, usually until burial. But the Cairo Genizah, originally located in the loft of the ancient Ben Ezra Synagogue and discovered in the late 19th century, contains more than decrepit prayer books.

The genizah in Cairo became a place to dispose of texts that were not just religious in origin, explains Prof. Wolf, such as merchant's lists, divorce documents and personal letters, spanning hundreds of years. It is the largest and most diverse collection of medieval manuscripts ever discovered. For this reason, he notes, the Genizah is an invaluable resource not just for Jewish studies, but also for the socioeconomic conditions of Middle Eastern life.

In conjunction with the Friedberg Genizah Project, which has received permission to digitize most of the fragments of the Genizah collection worldwide, Profs. Wolf and Dershowitz are working to put the pieces back together -- no easy task, given the dispersal of fragments around the globe. Whereas scholars concentrate primarily on content, the software looks at features of the writing itself, since it cannot read what is written. Using computer vision and image processing tools developed at TAU, the software analyzes fragments based on parameters such as the handwriting, the physical properties of the page and the spacing between lines of writing. The program scans digitized fragments for "matches," and joins them together in a kind of digital loose-leaf binder. "Its big advantage is that it doesn't tire after examining thousands of fragments," Prof. Dershowitz says. A scholar must then review and verify the computer-proposed "joins."

So far, Prof. Wolf says, the researchers have had a great deal of success. Within a few months, they made some 1,000 confirmed "joins," almost as many as were made in 100 years of Cairo Genizah scholarship. One exciting find, he notes, was the identification of pages from a work by Saadia Gaon, a prominent rabbi and philosopher from the 10th century. "All extant specimens of his work were thought to have been already discovered," he explains.

Read more at Science Daily

Glowing Sand Tells Time: No Hourglass Needed

If you want to get ready for the next big tsunami, hurricane or other storm surge, you need to know how far inland the roiling seawater is likely to go. A group of scientists in the Netherlands now say some of the best clues about future flooding may come from glow-in-the-dark sand buried in seaside dunes.

Conveniently, sand grains washed onshore during storms (see photo above) have a special way of tracking the time since the moment they came to rest. Deciphering this code made it possible for researchers from Delft University of Technology in the Netherlands to identify the timing and extent of a record-breaking storm that hammered the Dutch coastline in the 1770s.

In this case, the scientists were able to match the dune record to historical reports, which provide nifty verification that their sand grain analysis holds water. But the really cool implication of their work is that systematic scouring of coastal dunes anywhere in the world could turn up records of coastal flooding no one was there to see. That’s why the team, led by Jakob Wallinga, earned the cover story in the upcoming November issue of the of the journal Geology.

The more scientists know about past events, the better they can predict the future. Knowledge of specific storms is vital for strengthening statistical predictions about how often storms occur and how storm tracks change over time. Those changes are particularly important because many weather patterns, such as the weird ones that plagued Europe and North America this past spring, are a result of multiple forces.

Low-lying countries such as the Netherlands are especially keen to get a handle on the changing threat of floods from the seas. Fewer people may be dying in extreme weather events now than in the past, but many more severe events are being reported.

And severe weather, particularly along the world’s heavily populated coastlines, is bound to get worse as global climate warms.

A major stumbling block in making good predictions is that no one kept rigorous records of storm surges and related flooding until the late 1800s. That’s where the sand grains come in; they can give scientists a record of all sorts of past storms not yet accounted for. Here’s a quick analogy for how the method, called optically stimulated luminescence, works:

Think of each sand grain as a rechargeable battery. Exposure to sunlight (say, as the grain churns in the roiling surf) zaps the grain’s charge to zero. But once the grain is buried (as the storm abates), it accumulates a charge at a predictable rate from the minuscule dose of radiation that surrounds us all the time (because radioactive elements in the Earth’s crust emit radiation as they decay). So, if scientists can extract the grain from its burial place without exposing it to light, they can shine their own lights on it in the lab to capture a signal that lets them calculate the date the grain’s charge was last reset.

Wallinga’s team extracted their prescient sand grains story from dunes piled up near the town of Heemskerk. The initial clue turned up in a fresh cliff face chiseled into the seaward side of the dunes during storms in 2007. Sandwiched among the newly visible sand layers was a convoluted bed of intact shells and chunks of brick too heavy to have blown in on the wind; only the pounding surf of a storm surge could have carried the debris that far, in some cases ripping the live animals from their seafloor homes before sweeping them landward.

By mapping this debris layer using ground-penetrating radar, Wallinga’s team determined from the sediment that at some point floodwaters had reached far higher than any other storm surge on record in the Netherlands, including one that killed 2,000 people in 1953. Luminescence dating of sand grains nestled among the shells pegged the storm as happening sometime between 1760 and 1785 -- which matched perfectly with written accounts of major storms that occurred in 1775 and 1776.

Read more at Discovery News

These Millipedes Can’t Hear, So Why Do They Sing?

Why would a young male sing when his species has no ears?

To get the girl, of course.

That’s the most likely explanation for noises made by Sphaerotherium, a little-known genus of giant pill millipedes found in South Africa.

Exactly why sound should be so important to creatures incapable of hearing is a puzzle, though one not often considered even by entomologists. The last scientist to wonder died tragically almost 40 years ago, before he could answer the question.

“There are very few people working with millipedes in the world,” said Thomas Wesener of German’s Alexander Koenig Research Museum, co-author of a November Naturwissenschaften study of the unexpectedly loud creatures. “There’s probably 100. And for whatever reason, nobody picks these guys.”

With more taxonomic families than entomologists to study them, many millipede species have been largely ignored since being discovered — an ignominious fate for a class of creatures directly descended from the first waves of animals to colonize land some 400 million years ago.

So it was with Sphaerotherium. Before Wesener, they were last studied by a young German entomologist named Ulrich Haacker, who in the late 1960s was a rising star in his field. In 1972, he traveled to South Africa, fixing his attentions on the nine noisy species of Sphaerotherium, one of the few millipede groups to produce any noise at all.

Haacker collected hundreds of specimens. He filmed and recorded them, methodically noting which animals made what sounds, and when they did it. It was the most thorough Sphaerotherium examination ever undertaken. But shortly after returning to Germany, he was diagnosed with a rare form of leukemia. Six weeks later, Haacker died.

The collection passed to one of his students, Stefan Fuchs. He went on to study honeybees, but carried Haacker’s massive box of millipedes from office to office until, in 2005, he read about Wesener’s discovery of a giant pill millipede species in Madagascar. Fuchs contacted Wesener. Joined by German zoologists Jörn Köhler and Didier Van den Spiegel, they set about bringing Haacker’s lost work to life.

An obvious clue to Sphaerotherium sounds — which technically are not singing, since millipedes don’t have voices, but rather stridulations generated by rubbing body parts together — is that only males make them, implying some reproduction-related function. Still, the baffling fact remained that giant pill millipedes can’t hear.

But another clue came from Haacker’s notes: Males stridulated primarily when encountering giant pill millipedes that had rolled into their eponymous, ping pong ball-sized defensive posture. As Sphaerotherium lack the poison glands typical of other millipedes, retreating into an armored ball is an all-purpose response to any approaching creature, their own species included.

Rolling, of course, is great for defense but inconvenient for mating. And though defenses against unwanted male attention are common in the animal kingdom, rolling into a ball would discourage desirable suitors, too.

Wondering if stridulations might somehow convince wary females to uncoil, Wesener’s team analyzed the stridulations in spectrographic detail and found species-specific patterns that varied in timing rather than pitch, like Morse code.

“Females probably recognize the vibrations of the male,” said Wesener. Indeed, millipedes have fine hair-like structures on their legs, used for detecting the movements of prey but appropriate to this purpose as well.

For now, this remains a hypothesis, though a very plausible one. So does the origin of stridulations, which appear to come from back-and-forth rubbing of guitar-and-pick formation on the millipedes’ pincers. Wesener hopes that other scientists will continue Haacker’s investigations.

Read more at Wired Science

Oct 19, 2011

Comet Armageddon Detected in Nearby Star System

A nearby star system is currently going through hell, as hinted at by NASA's Spitzer Space Telescope. Through its infrared eye, Spitzer has detected the dusty remains of comet impacts around the star Eta Corvi -- reminding us what it must have been like during the early evolution of our own solar system.

During our solar system's "Late Heavy Bombardment" (LHB) some four billion years ago, the inner planets were constantly peppered with massive comets impacting their surfaces. Earth would have been unrecognizable -- the planet's surface was a burning, molten mess; young atmosphere constantly punctuated by incoming cometary fragments.

Devoid of any eroding atmosphere, the moon's surface bears the scars of this epic cometary onslaught -- huge impact craters providing a reminder of how violent the "early years" of our solar system really was.

Despite the continuous cycle of cataclysmic impact events generating a hellish cauldron on Earth, the LHB has been linked with the genesis of life -- evidence points to a cometary source for the organic ingredients. Needless to say, the growing pains inflicted by the LHB on our planet is of huge importance to scientists.

Therefore, to spot the signs of similar cometary bombardments in other star systems would be pretty awesome. Not only would that help us understand the evolution of planetary systems orbiting other stars, it would provide a "time capsule" for us to have a glimpse of the early life of our own solar system. Of course, it would also give us an idea of how many other stars could be "ripe" for life (as we know it).

Now, scientists using observations by Spitzer have detected cometary Armageddon around Eta Corvi, a star some 50 light-years away in the constellation Corvus.

A ring of warm dust closely surrounds Eta Corvi, and after analysis of the dust, it appears to have the same chemistry as pulverized comets -- water ice, rock and organics. This provides the hint that the star may be going through a similar phase as the early solar system -- comets are careening inward, colliding with as-yet to be detected planetary bodies.

The star is approximately a billion years old, an age that scientists estimate is "just right" for a cometary hailstorm to occur.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

Not only does the chemical fingerprint of the debris surrounding Eta Corvi demonstrate active impacts from a huge reservoir of comets, the dust's chemistry resembles that of the Almahata Sitta meteorite, fragments of which fell to Earth in Sudan in 2008. This suggests ancient material floating around in the solar system may have a common formation process as the material getting bashed up in Eta Corvi.

The similarities don't end there. There is evidence of another, cooler dusty ring further away from the star than the cometary impact debris, approximately 150 AU (150 times the Earth-sun distance) from Eta Corvi. The ring was detected in 2005 and could be the location of cometary nuclei, asteroids and other debris. The solar system has a region at roughly the same distance -- the Kuiper Belt.

Could this outer, cool ring be the source of the comets currently smashing through the inner Eta Corvi system? Possibly.

This is a fascinating study as Spitzer has gleaned an insight to the nature of a star system, possibly containing several planetary bodies -- after all, it was the migration of Jupiter and Saturn in the early history of the solar system that kick-started the LHB in the first place. Perhaps Eta Corvi is currently undergoing a similar process.

Read more at Discovery News

'Promising' Step for World's First Malaria Vaccine

The search for the world's first malaria vaccine received a boost Tuesday with the release of early results from a major clinical trial showing it cut risk by about half in African children.

The vaccine known as RTS,S is made by the British pharmaceutical giant GlaxoSmithKline's lab in Belgium, and is the first of its kind to attempt to block a parasite, rather than bacteria or viruses.

Experts hailed the phase III trial under way at 11 sites in sub-Saharan Africa as a promising step toward eradicating the ancient mosquito-borne disease that kills almost 800,000 people yearly, most of them children.

The results are published online in the New England Journal of Medicine, and were simultaneously announced at the Malaria Forum hosted by the Bill & Melinda Gates Foundation in Seattle, Washington.

In a statement, philanthropist and Microsoft tycoon Bill Gates described the findings as a "huge milestone" in the fight against malaria, that "has the potential to protect millions of children and save thousands of lives."

Children aged five to 17 months who received three doses of the vaccine saw a 56 percent lower risk of developing clinical malaria, which causes high fever and chills, according to the study.

When it came to severe malaria -- the stage of the illness that can be fatal and reaches the blood, brain or kidneys -- those who received the vaccine showed a 47 percent lower risk.

"This is remarkable when you consider that there has never been a successful vaccine against a human parasite," said Tsiri Agbenyega, who chairs the RTS,S Clinical Trials Partnership and heads malaria research at Komfo-Anokye Teaching Hospital in Kumasi, Ghana.

"While these results are encouraging, we still have a ways to go," he told reporters.

The analysis was done with data from 6,000 children in the trial over a 12-month follow up after vaccination.

More data is needed from the younger age group -- infants aged six to 12 weeks -- to better assess how well it works in this particularly vulnerable group, experts said. Additional results from the younger set are due next year.

The World Health Organization says malaria claimed 781,000 lives in 2009. About 90 percent of malaria deaths each year occur in Africa and 92 percent of those are children less than five years old.

Asked whether the Gates Foundation would get behind a vaccine with a success rate of only about half, Regina Rabinovich, director for infectious diseases at the foundation's global health program, was circumspect.

"This is a key question. The group will ultimately want to understand efficacy, duration and safety," she said, adding she was "enthusiastic" about the results so far and was awaiting further data.

More than 15,000 children in seven African countries are enrolled in the trial, which is set to continue for two more years, and covers areas with other interventions in place against malaria, such as bed nets and spraying.

RTS,S was created in 1987 in GlaxoSmithKline Biologicals' lab in Belgium. Testing began on healthy adults in Europe and the United States in 1992, before the first Africa study started in Gambia in 1998.

Trial sites are now located in Burkina Faso, Gabon, Ghana, Kenya, Malawi, Mozambique and Tanzania, including 15,460 infants and young children in what GSK described as "the largest malaria vaccine trial to date."

The vaccine works by triggering the immune system to defend the body against Plasmodium falciparum, the deadliest type of malaria parasite.

Side effects included fever and swelling at injection site, "what you would typically see in other childhood vaccinations," said Agbenyega.

Read more at Discovery News

Spooky Eye Contacts Can Damage Eyes

Think twice before buying that pair of spooky eye contacts for Halloween without a prescription.

Sure, they can give you cat eyes or perfectly complement your ghastly attire. But they can come at a high cost: permanent eye damage, experts say.

The FDA recently released a friendly reminder on how to safely buy the lenses with a less welcoming list of ailments Halloween goers experience from sporting non-prescription decorative eye contacts on the holiday.

These types of contacts aren't designed to improve a person's vision, but rather to change how the eyes look. Like other contacts, decorative lenses need to be sized by an eye doctor to fit well. Although it might not be the first thing on Halloween shoppers' minds, decorative contacts should be purchased with a prescription.

In fact, anyone selling the lenses without a prescription is breaking the law, says the FDA, considering the fact that regular contacts and decorative types fall under FDA-regulated medical devices.

Buying the creepy eyes from unregulated vendors might save money, but it's illegal business and increases a person's risk of eye damage. Common ailments include scratched corneas (the outer portion of the eyeball), ulcers, pink eye and some vision loss. In some cases, people become blind.

Not washing the lenses or buying a size that doesn't fit usually spurs infection.

Most doctors can accommodate decorative prescriptions, but few will give into recommending the large circle lenses that recreate large eyes seen in anime cartoons Clinics often subject people to an eye exam before signing off on Halloween contacts.

Read more at Discovery News

Ancient Images of a Mother Giving Birth Found

An international team of archaeologists has unearthed what might be the earliest representation of childbirth in western art, they announced today.

Consisting of two images of a woman giving birth to a child, the intimate scene was found on a small fragment from a ceramic vessel that is more than 2,600 years old.

It was excavated by William Nutt, a graduate student in anthropology at the University of Texas at Arlington who is legally blind.

About 1-3/4 x 1-1/4 inches (4 x 3 cm), the fragment was part of a vessel made of bucchero, a typically Etruscan black pottery.

The image show the head and shoulders of a baby emerging from a mother. Portrayed with her face in profile and a long ponytail running down her back, the woman has her knees and one arm raised.

The image could be the earliest representation of childbirth in western art, according to Phil Perkins, professor of archaeology at the Open University, in Milton Keynes, England.

"Such images are rare in ancient and classical art. A few, much later Greek and Roman images are known, but this one dates to about 600 B.C.," Perkins, who first identified the scene, told Discovery News.

A fun loving and eclectic people who among other things taught the French how to make wine, the Romans how to build roads, and introduced the art of writing into Europe, the Etruscans began to flourish around 900 B.C., and dominated much of Italy for five centuries.

Known for their art, agriculture, fine metalworking and commerce, they begun to decline during the fifth century B.C., as the Romans grew in power. By 300-100 B.C., they eventually became absorbed into the Roman empire.

Since their puzzling, non-Indo-European language was virtually extinguished (they left no literature to document their society),the Etruscans have long been considered one of antiquity’s great enigmas.

Indeed, much of what we know about them comes from their cemeteries: only the richly decorated tombs they left behind have provided clues to fully reconstruct their history.

Poggio Colla is one of the few sites offering insight of the Etruscan life in a non-funerary context. It spans most of Etruscan history, being occupied from the seventh to the second century B.C.

Centering on the acropolis, a roughly rectangular plateau, the site was also home to a sanctuary: numerous votive deposits indicate that for some part of its history, it was a sacred spot to a divinity or divinities.

The abundance of weaving tools and a stunning deposit of gold jewelry discovered in previous excavations, have suggested that the patron divinity may have been female.

In this view, the ancient depiction of childbirth becomes even more interesting, according to Greg Warden, professor and associate dean for academic affairs at the Meadows School of the Arts at SMU and a director of the Mugello Valley Archaeological Project.

Read more at Discovery News

Oct 18, 2011

Frozen Puck Hovers Over Track Using “Quantum Levitation”

Researchers at the school of physics and astronomy at Tel Aviv University have created a track around which a semiconductor can float, thanks to the phenomenon of “quantum levitation“.

This levitation effect is explained by the Meissner effect, which describes how, when a material makes the transition from its normal to its superconducting state, it actively excludes magnetic fields from its interior, leaving only a thin layer on its surface.

When a material is in its superconducting state — which involves very low temperatures — it is strongly diamagnetic. This means that when a magnetic field is externally applied, it will create an equally opposing magnetic field, locking it in place.

A material called yttrium barium copper oxide can be turned into a superconductor by exposure to liquid nitrogen — which makes it one of the highest-temperature superconductors.

Read more at Wired Science

Taxi Driver Mummified Like Pharaohs

A former British taxi driver has become mummified in the same way as the pharaohs.

Viewers of England's Channel 4 will see Alan Billis turned into a mummy over the space of a few months as his body is preserved using the techniques which the ancient Egyptians used on Tutankhamun.

Billis had been terminally ill with cancer when he volunteered to undergo the procedure which a scientist has been working to recreate for many years.

The 61-year-old from Torquay in Devon had the backing of his wife Jan, who said: "I'm the only woman in the country who's got a mummy for a husband."

The process is revealed in a new documentary Mummifying Alan: Egypt's Last Secret to be screened next Monday, October 24.

Stephen Buckley, a chemist and research fellow at York University, has spent 19 years trying to uncover the preservation techniques which the Egyptians used during the 18th dynasty.

Alongside archaeologist Jo Fletcher, Buckley has studied mummified bodies, analyzing tissue samples and finally putting his findings into practice by putting them to the test on Mr Billis's body at Sheffield's Medico-Legal Centre.

"It's turned current understanding, including my own, completely on its head," said Buckley.

Billis had been diagnosed with terminal lung cancer when he heard about the search for a body donor.

"I was reading the paper and there was a piece that said 'volunteer wanted with a terminal illness to donate their body to be mummified,'" he told the documentary team.

"People have been leaving their bodies to science for years and if people don't volunteer for anything nothing gets found out."

Billis -- who dubbed himself "Tuten-Alan" -- continued: "Experimenting is all about trying different processes to make things work. If it doesn't work it's not the end of the world, is it? Don't make any difference to me, I'm not going to feel it. It's still bloody interesting."

His wife took his decision in her stride and said: "He just said, 'I've just phoned someone up about being mummified.' I said 'you've what?' 'Yes, I've phoned up someone about being mummified.'

"And I thought here we go again. What's going to go on now? It's just the sort of thing you would expect him to do."

Buckley has used specialist scientific equipment such as a gas chromatograph mass spectrometer to identify materials which were used by priests, including beeswax, oils and resins.

He went on to conduct a series of experiments using pigs' legs as a substitute for human flesh, rigging up makeshift desert conditions in his shed.

Read more at Discovery News

What it means to donate your brain

“At 92 years old, Albert Webb is wandering through an exhibition in London’s trendy Shoreditch. In the underground warren of rooms, echoes of recorded voices mingle with the sounds of people’s conversations. The occasional burst of laughter bounces around the walls. Wearing a white sweater that he knitted himself, Webb leans in to tell me his story. When he smiles his eyes disappear into thin creases, giving him an air of gleefulness.

A grin may seem an odd response to the question I’ve just asked – why he chose to donate his brain to medical research – but after 17 years participating in a brain study led by the aptly named Carol Brayne of the University of Cambridge, Webb discusses his decision with ease. To him, donation secures a form of immortality.

He explains that he’d knit the sweater he’s wearing many years ago, before he lost his wife Ellen. Knitting was something they had done together. “When she died, I packed it in,” he says. She had dementia toward the end of her life. This Saturday marks the ninth anniversary of her death. They were married for 57 years.

It’s a poignant story in a fitting setting. We are standing in the middle of Mind Over Matter, an exhibition inspired by the research of Brayne and colleagues that is the result of a long collaboration between artist Ania Dabrowska and social scientist Bronwyn Parry. The exhibition focuses on 12 brain donors from Brayne’s studies – the stories of their lives and triumphs, and their reasons for donating.”

Read more at New Scientist

Cyclops Shark & Other Cryptic Creatures Make October Creepy

In this world of Photoshop and online scams, it pays to have a hearty dose of skepticism at reports of something strange — including an albino fetal shark with one eye smack in the middle of its nose like a Cyclops.

But the Cyclops shark, sliced from the belly of a pregnant mama dusky shark caught by a commercial fisherman in the Gulf of California earlier this summer, is by all reports the real thing. Shark researchers have examined the preserved creature and found that its single eye is made of functional optical tissue, they said last week. It's unlikely, however, that the malformed creature would have survived outside the womb.

"This is extremely rare," shark expert Felipe Galvan Magana of Mexico's Centro Interdisciplinario de Ciencias del Mar told the Pisces Fleet Sportfishing blog in July. "As far as I know, less than 50 examples of an abnormality like this have been recorded." [See photos of the one-eyed "Cyclops" shark]

Pisces Fleet, a sportfishing company, rocketed the Cyclops shark to viral status online this summer with their photos of the creepy-cute creature. But this isn't the first time that reports of a mythical-seeming creature have spurred media sensations — last week alone, Russian officials announced "proof" of a Yeti, and paleontologists spun a theory about an ancient Kraken-like squid. Few reports of mythical beasts, however, come with proof.

Cyclops shark

The Cyclops shark is an exception. While rare, "cyclopia" is a real developmental anomaly in which only one eye develops. Human fetuses are sometimes affected, as in a 1982 case in Israel reported in 1985 in the British Journal of Ophthalmology. In that case, a baby girl was born seven weeks early with no nose and only one eye in the center of her face. The infant, who lived only 30 minutes after birth, also had severe brain abnormalities.

In 2006, a kitten born with one eye and no nose (a rare condition called holoprosencephaly), created a stir online as news organizations and bloggers tried to determine if the bizarre photos of the animal were real. A veterinarian confirmed the kitten's condition; "Cy," as the cat was known, lived only a day. The remains were sold to the creationist Lost World Museum.

The fisherman who discovered the Cyclops shark is reportedly hanging on to the preserved remains, news outlets reported. But scientists have recently examined and X-rayed the fish, authenticating the catch. According to Seth Romans, a spokesman for Pisces Fleet, Galvan Magana and his colleagues will publish a scientific paper about the find within the next several weeks.

Romans told LiveScience that the fisherman who caught the strange shark is "amazed and fascinated" by the attention his catch has drawn.

It's not the first strange shark fetus Galvan Magana has found; he and his colleagues discovered two-headed shark embryos in two different female blue sharks. It's possible that one embryo started to split into twins, but failed to completely separate because of crowding in the womb, the researchers reported in January 2011 in the journal Marine Biodiversity Records.

Lair of the kraken?

Another recent report of a cryptic creature comes without the benefit of photographic evidence. Nor do the monster-hunters in this scenario have a body to display.   

That's because the discovery is of an alleged "kraken's lair," a spot where 200-million-year-old ichthyosaur bones mingle in odd patterns. Paleontologist Mark McMenamin reads these patterns as evidence of a giant, ancient squid-like creature playing with its food, and he said as much on Oct. 10 at the annual meeting of the Geological Society of America. Supporting his claim, he said, is the fact that even today Pacific octopus, which are also cephalopods like the ancient "kraken," have been seen taking down sharks.

Other researchers responded that McMenamin was seeing what he wanted to see in the patterns.

"To my mind, this hypothesis is like looking at clouds — being able to see what you desire," Glenn Storrs, the curator of vertebrate paleontology at the Cincinnati Museum Center, told LiveScience.

Mythical krakens are now thought of as giant squid or octopuses, capable of bringing down a ship with their tentacled arms. But many of the earliest kraken reports were of creatures so enormous that they grew vegetation on their backs like islands. These krakens dragged down anchored ships or swamped them by surfacing suddenly. [Read Get Kraken: Why Scientists Should Study Sea Monsters]

The 1816 "Universal Dictionary of the Arts, Sciences Literature, Etc.," (advertised as "intended to supersede the use of other books of reference") defines the kraken as "a most amazing large sea animal," said to be "of a crab-like form."

"Its back or upper part, which seems an English mile and a half (some have affirmed more), looks at first like a number of small islands, surrounded with something that floats like seaweeds," the dictionary author writes. "At last several bright points of horns appear, which grow thicker the higher they emerge, and sometimes stand up as high and large as the masts of middle-sized vessels. In a short time, it slowly sinks, which is thought as dangerous as its rising; as it causes such a swell and whirlpool as draws everything down with it."

Read more at Yahoo! News

Oct 17, 2011

Archaeologists Find Blade 'Production Lines' Existed as Much as 400,000 Years Ago

Archaeology has long associated advanced blade production with the Upper Palaeolithic period, about 30,000-40,000 years ago, linked with the emergence of Homo Sapiens and cultural features such as cave art. Now researchers at Tel Aviv University have uncovered evidence which shows that "modern" blade production was also an element of Amudian industry during the late Lower Paleolithic period, 200,000-400,000 years ago as part of the Acheulo-Yabrudian cultural complex, a geographically limited group of hominins who lived in modern-day Israel, Lebanon, Syria and Jordan.

Prof. Avi Gopher, Dr. Ran Barkai and Dr. Ron Shimelmitz of TAU's Department of Archaeology and Ancient Near Eastern Civilizations say that large numbers of long, slender cutting tools were discovered at Qesem Cave, located outside of Tel Aviv, Israel. This discovery challenges the notion that blade production is exclusively linked with recent modern humans.

The blades, which were described recently in the Journal of Human Evolution, are the product of a well planned "production line," says Dr. Barkai. Every element of the blades, from the choice of raw material to the production method itself, points to a sophisticated tool production system to rival the blade technology used hundreds of thousands of years later.

An innovative product

Though blades have been found in earlier archaeological sites in Africa, Dr. Barkai and Prof. Gopher say that the blades found in Qesem Cave distinguish themselves through the sophistication of the technology used for manufacturing and mass production.

Evidence suggests that the process began with the careful selection of raw materials. The hominins collected raw material from the surface or quarried it from underground, seeking specific pieces of flint that would best fit their blade making technology, explains Dr. Barkai. With the right blocks of material, they were able to use a systematic and efficient method to produce the desired blades, which involved powerful and controlled blows that took into account the mechanics of stone fracture. Most of the blades of were made to have one sharp cutting edge and one naturally dull edge so it could be easily gripped in a human hand.

This is perhaps the first time that such technology was standardized, notes Prof. Gopher, who points out that the blades were produced with relatively small amounts of waste materials. This systematic industry enabled the inhabitants of the cave to produce tools, normally considered costly in raw material and time, with relative ease.

Thousands of these blades have been discovered at the site. "Because they could be produced so efficiently, they were almost used as expendable items," he says.

Prof. Cristina Lemorini from Sapienza University of Rome conducted a closer analysis of markings on the blades under a microscope and conducted a series of experiments determining that the tools were primarily used for butchering.

Read more at Science Daily

Super-Sized Muscle Made Twin-Horned Dinosaur a Speedster

A meat-eating dinosaur that terrorized its plant-eating neighbours in South America was a lot deadlier than first thought, a University of Alberta researcher has found. Carnotaurus was a seven-metre-long predator with a huge tail muscle that U of A paleontology graduate student Scott Persons says made it one of the fastest running hunters of its time.

A close examination of the tail bones of Carnotaurus showed its caudofemoralis muscle had a tendon that attached to its upper leg bones. Flexing this muscle pulled the legs backwards and gave Carnotaurus more power and speed in every step.

In earlier research, Persons found a similar tail-muscle and leg-power combination in the iconic predator Tyrannosaurus rex. Up until Persons published that paper, many dinosaur researchers thought T. rex's huge tail might have simply served as a teeter-totter-like counterweight to its huge, heavy head.

Persons' examination of the tail of Carnotaurus showed that along its length were pairs of tall rib-like bones that interlocked with the next pair in line. Using 3-D computer models, Persons recreated the tail muscles of Carnotaurus. He found that the unusual tail ribs supported a huge caudofemoralis muscle. The interlocked bone structure along the dinosaur's tail did present one drawback: the tail was rigid, making it difficult for the hunter to make quick, fluid turns. Persons says that what Carnotaurus gave up in maneuverability, it made up for in straight ahead speed. For its size, Carnotaurus had the largest caudofemoralis muscle of any known animal, living or extinct.

Read more at Science Daily

Avoiding Bias in Medical Research

Most people are rather vague when reporting on food and drink consumption, smoking and exercise habits. General practitioners, however, are skilled at interpreting phrases such as "I only have a few drinks rarely...each week" and "I get to the gym regularly" and can estimate based on symptoms and a person's physical appearance just how precise those claims are. However, it is crucial for healthcare research and epidemiology that relies on patient self-reporting that we find a more objective, rather than intuitive, way to identify bias in self-reporting.

A new statistical approach to address the problem of bias in self-reporting has been developed by a team at Washington State University in Pullman. The technique, reported in a forthcoming issue of the International Journal of Behavioural and Healthcare Research, is based on stochastic frontier estimation (SFE). SFE is more commonly used in economics and market research to spot statistical errors and unanticipated deviations from the norms in data. The approach helps highlight when the subjects of medical research may either deliberately or inadvertently bias the information they provide to researchers.

"There are many reasons individuals might offer biased estimates of self-assessed behavior, ranging from a misunderstanding of what a proper measurement is to social-desirability bias, where the respondent wants to 'look good' in the survey, even if the survey is anonymous," explains Robert Rosenman, who coauthored the study with Laura Hill and Vidhura Tennekoon. "Response bias itself can be problematic in program evaluation and research, but is especially troublesome when it causes a recalibration of bias after an intervention," he adds.

SFE can identify bias at specific times in self-reported data and in particular identify bias after a healthcare intervention so that researchers can determine whether or not self-reporting patients have biased their responses because they presume the intervention should have caused changes. This characteristic of the technique could ensure that double-blind placebo-controlled trials are more robust in terms of the validity of data. It could help improve results obtained before and after an experimental treatment is given to one group and the placebo to another when neither party, patient or researcher, is aware in advance of which group a patient is in.

Read more at Science Daily

Dark Matter: Now More Mysterious Than Ever

Astronomers have one more reason to scratch their heads over the unseen material known as dark matter. Observations of two dwarf galaxies, Fornax and Sculptor, show the dark matter within them is spread out smoothly rather than heaped into a central bulge, contradicting cosmological models.

Researchers know dark matter comprises a far greater percentage of the universe than the ordinary matter making up things like people and stars. Because of this, the distribution of dark matter determines the structure of the cosmos. Galaxies form when they are attracted to and anchored by large clumps of dark matter.

The dwarf galaxies Fornax and Sculptor are themselves made of 99 percent dark matter and only 1 percent normal matter. It is impossible to directly see the dark matter but, by observing the rotation of stars around each galactic center, researchers can detect its influence and map out its distribution.

While simulations suggest that the dark-matter density should increase sharply near the galactic centers, the recent observations found the dark matter spread relatively uniform throughout. Yet if these dwarf galaxies have no “clump” in their center, then what is pinning them in place?

Observations of other small galaxies have similarly failed to find a dense central dark matter core, a difficulty that has prompted astronomers to begin expanding their ideas on the mysterious substance.

Read more at Wired Science

Oct 16, 2011

How the Zebra Gets Its Stripes: A Simple Genetic Circuit

Many living things have stripes, but the developmental processes that create these and other patterns are complex and difficult to untangle.

Now a team of scientists has designed a simple genetic circuit that creates a striped pattern that they can control by tweaking a single gene.

"The essential components can be buried in a complex physiological context," said Terence Hwa, a professor of physics at the University of California, San Diego, and one of the leaders of the study published October 14 in Science. "Natural systems make all kinds of wonderful patterns, but the problem is you never know what's really controlling it."

With genes taken from one species of bacterium and inserted into another, Hwa and colleagues from the University of Hong Kong assembled a genetic loop from two linked modules that senses how crowded a group of cells has become and responds by controlling their movements.

One of the modules secretes a chemical signal called acyl-homoserine lactone (AHL). As the bacterial colony grows, AHL floods the accumulating cells, causing them to tumble in place rather than swim. Stuck in the agar of their dish, they pile up.

Because AHL doesn't diffuse very far, a few cells escape and swim away to begin the process again.

Left to grow overnight, the cells create a target-like pattern of concentric rings of crowded and dispersed bacterial cells. By tweaking just one gene that limits how fast and far cells can swim, the researchers were able to control the number of rings the bacteria made. They can also manipulate the pattern by modifying how long AHL lasts before it degrades.

Although individual bacteria are single cells, as colonies they can act like a multicellular organism, sending and receiving signals to coordinate the growth and other functions of the colony. That means fundamental rules that govern the development of these patterns could well apply to critical steps in the development of other organisms.

To uncover these fundamental rules, Hwa and colleagues characterized the performance of their synthetic genetic circuit in two ways.

First, they precisely measured both the activity of individual genes in the circuit throughout the tumble-and-swim cycle. Then they derived a mathematical equation that describes the probability of cells flipping between swim and tumble motions.

Additional equations describe other aspects of the system, such as the dynamics of the synthesis, diffusion and deactivation of one of the cell-to-cell chemical signal AHL.

This three-pronged approach of "wet-lab" experiments, precise measurements of the results, and mathematical modeling of the system, characterize the emerging discipline of quantitative biology, Hwa said. "This is a prototype, a model of the kind of biology we want to do."

Read more at Science Daily

Giving placebos such as reiki to cancer patients does more harm than good

American nurses recently published an intriguing study with bizarre conclusions. They recruited almost 200 patients who were receiving chemotherapy for cancer. This is, of course, a difficult time for most cancer sufferers. There may be side-effects such as hair loss, nausea, fatigue, depression etc. All of these are bound to decrease patients' wellbeing. So the nurses tested whether a session of reiki healing would improve the general wellbeing of their patients.

Reiki involves channelling "healing energy" into the body. Lots of people swear by it, but does it really work?

To find out, a proper control group is essential. The researchers therefore decided to compare reiki against "sham reiki" and against no such intervention. Sham reiki involved a non-reiki healer pretended to be a reiki healer. He was not trained in reiki and only followed the ritual of the treatment. So he did not send any "healing energy" to the patients whereas the reiki healer had been taught to do just that.

The results of this study were impressive: reiki did, in fact, make the patients fell better. Specifically, it increased the comfort and wellbeing of the patients in comparison with those who received no such intervention. Intriguingly, however, the sham reiki had exactly the same effects, and there were no differences between real and sham reiki.

What does this mean? The researchers were quite clear about their interpretation of the results. They believe reiki has been shown to work. Yet, I think the findings demonstrate exactly the opposite: genuine reiki is no better than sham reiki, thus it does not work.

Perhaps this is a rather academic matter of interpretation over which one could argue until the cows come home. However, the more pressing question is this: what should oncology teams throughout the world do about such findings?

Should they use reiki or similar therapies, as these American nurses seem to be suggesting? They clearly help desperately ill cancer patients, . Or should they avoid such treatments, because they are no better than placebo, as I and most scientists would suggest?

The scientific stance may appear heartless and cruel in light of the suffering of cancer patients, while the attitude of the nurses seems patient-centred and caring. This impression is wrong. By insisting that patients must not be treated with placebos like reiki, scientists also advocate that they receive treatments that demonstrably work better that placebo. For instance, massage has been shown to improve the wellbeing of cancer patients beyond a placebo effect. If a patient receives a massage with empathy, sympathy, time, understanding and dedication, she would benefit from the placebo effect – just like the reiki patient – but, in addition, she would also benefit from the specific effect of the treatment that massage does and Reiki does not offer.

Read more at The Guardian