Jan 14, 2012

I Recognise You! But How Did I Do It?

Are you someone who easily recognises everyone you've ever met? Or maybe you struggle, even with familiar faces? It is already known that we are better at recognising faces from our own race but researchers have only recently questioned how we assimilate the information we use to recognise people.

New research by the University of Nottingham Malaysia Campus has shown that when it comes to recognising people the Malaysian Chinese have adapted their facial recognition techniques to cope with living in a multicultural environment.

The study 'You Look Familiar: How Malaysian Chinese Recognise Faces' was led by Chrystalle B.Y. Tan, a PhD student at the University of Nottingham Malaysia Campus. The results have been published online in the scientific journal PLoS One, This research is the first PhD student publication for Nottingham's School of Psychology in Malaysia.

Chrystalle Tan said: "Our research has shown that Malaysian Chinese adopt a unique looking pattern which differed from both Westerners and Mainland Chinese, possibly due to the multicultural nature of the country."

The ability to recognise different faces may have social and evolutionary advantages. Human faces provide vital information about a person's identity and characteristics such as gender, age, health and attractiveness. Although we all have the same basic features we have our own distinguishing features and there is evidence that the brain has a specialised mental module dedicated to face processing.

Recognition techniques

Previous research by a group at Glasgow University in Scotland showed that Asians from mainland China use more holistic recognition techniques to recognise faces than Westerners.

    Chinese focus on the centre of the face in the nose area
    Westerners focus on a triangular area between the eyes and mouth
    British born Chinese use both techniques fixating predominantly around either the eyes and mouth, or the nose

Chrystalle said: "The traditional view is that people recognise faces by looking in turn at each eye and then the mouth. This previous research showed us that some Asian groups actually focus on the centre of the face, in the nose area. While Westerners are learning what each separate part of the face looks like -- a strategy that could be useful in populations where hair and eye colour vary dramatically, mainland Chinese use a more global strategy, using information about how the features are arranged. Meanwhile British born Chinese use a mixture of both techniques suggesting an increased familiarity with other-race faces which enhances their recognition abilities."

Eye tracking technology

The study by the School of Psychology at the University of Nottingham Malaysia Campus set out to investigate whether exposure and familiarity with other cultures affects our recognition accuracy and eye movement strategies.

The team used specialised eye tracking technology to investigate the visual strategies used to recognise photographs of faces. They recruited 22 Malaysian Chinese student volunteers from across Nottingham's Malaysia campus. The results showed that Malaysian Chinese used a unique mixed strategy by focusing on the eyes and nose more than the mouth.

Chrystalle said: "We have shown that Malaysian Chinese adopt a unique looking pattern which differed from both Westerners and mainland Chinese. This combination of Eastern and Western looking patterns proved advantageous for Malaysian Chinese to accurately recognise Chinese and Caucasian faces."

Read more at Science Daily

'BoRG' Survey Spots Ancient Cluster of Baby Galaxies

Galactic clusters are the largest structures in the Universe. Spanning millions of light-years, they are groupings of galaxies connected to each other by gravity and moving inexorably outwards together within our ever-expanding universe.

Our own galaxy is part of a cluster known as the Local Group, which contains at least 45 individual galaxies. It takes time for galaxies to organize into groups like this, and while it's not known exactly how long this process may take astronomers now have a new piece for the puzzle.

A team of researchers using infrared data from Hubble's Wide Field Camera 3 have located five small and incredibly distant galaxies that appear to be bound together gravitationally, making this the furthest galactic cluster ever seen. Located 13.1 billion light-years away, this protocluster appears as it did only 600 million years after the birth of the universe.

The individual galaxies are much smaller than our own (one-half to one-tenth the size) and can only be detected in near-infrared, as their light has been stretched beyond the visible spectrum due to their sheer distance.

The discovery was made during a random sky search, part of the Brightest of Reionizing Galaxies (BoRG) survey which scans the sky in near-infrared, attempting to locate distant sources of energy. The image above circles the locations of the five galaxies within a visible light image of the surrounding region while the individual galaxies are shown down the right side in infrared.

The team, led by Michele Trenti of the University of Colorado at Boulder and the Institute of Astronomy at the University of Cambridge in the UK, has been faced with quite a challenge because of the dimness of these distant objects. Locating them is a "hit-and-miss" process.

"We need to look in many different areas because the odds of finding something this rare are very small," said Trenti. "Typically, a region has nothing, but if we hit the right spot, we can find multiple galaxies."

Since these young galaxies are seen as they were over 13 billion years ago, it's assumed they have long since gathered together to form one of the giant modern "galactic city" clusters we see today... such as the nearby Virgo cluster which now contains over 2,000 galaxies.

Read more at Discovery News

Jan 13, 2012

Mystery of Source of Supernova in Nearby Galaxy Solved

Using NASA's Hubble Space Telescope, astronomers have solved a longstanding mystery of the type of star, or so-called progenitor, which caused a supernova seen in a nearby galaxy. The finding yields new observational data for pinpointing one of several scenarios that trigger such outbursts.

Based on previous observations from ground-based telescopes, astronomers knew that a kind of supernova called a Type Ia supernova created a remnant named SNR 0509-67.5, which lies 170,000 light-years away in the Large Magellanic Cloud galaxy.

The type of system that leads to this kind of supernova explosion has long been a high importance problem with various proposed solutions but no decisive answer. All these solutions involve a white dwarf star that somehow increases in mass to the highest limit.

Astronomers failed to find any companion star near the center of the remnant, and this rules out all but one solution, so the only remaining possibility is that this one Type Ia supernova came from a pair of white dwarfs in close orbit.

"We know that Hubble has the sensitivity necessary to detect the faintest white dwarf remnants that could have caused such explosions," said lead investigator Bradley Schaefer of Louisiana State University (LSU) in Baton Rouge. "The logic here is the same as the famous quote from Sherlock Holmes: 'when you have eliminated the impossible, whatever remains, however improbable, must be the truth.'"

The cause of SNR 0509-67.5 can be explained best by two tightly orbiting white dwarf stars spiraling closer and closer until they collided and exploded.

The results are being reported January 11 at the meeting of the American Astronomical Society in Austin, Texas. A paper on the results will be published in the Jan. 12 issue of the journal Nature.

For four decades, the search for Type Ia supernovae progenitors has been a key question in astrophysics. The problem has taken on special importance over the last decade with Type Ia supernovae being the premier tools for measuring the accelerating universe.

Type Ia supernovae are tremendous explosions of energy in which the light produced is often brighter than a whole galaxy of stars. The problem has been to identify the type of star system that pushes the white dwarf's mass over the edge and triggers this type of explosion. Many possibilities have been suggested, but most require that a companion star near the exploding white dwarf be left behind after the explosion.

Therefore, a possible way to distinguish between the various progenitor models has been to look deep in the center of an old supernova remnant to search for the ex-companion star.

In 2010, Schaefer and Ashley Pagnotta of LSU were preparing a proposal to look for any faint ex-companion stars in the center of four supernova remnants in the Large Magellanic Cloud when they discovered that the Hubble Space Telescope had already taken the desired image of one of their target remnants, SNR 0509-67.5, for the Hubble Heritage program, which collects images of especially photogenic astronomical targets.

In analyzing the central region, they found it to be completely empty of stars down to the limit of the faintest objects that Hubble can detect in the photos. Schaefer reports that the best explanation left is the so-called "double degenerate model" in which two white dwarfs collide.

There are no recorded observations of the star exploding. However, researchers at the Space Telescope Science Institute in Baltimore, Md., have identified light from the supernova that was reflected off of interstellar dust, delaying its arrival at Earth by 400 years. This delay, called a light echo of the supernova explosion also allowed the astronomers to measure the spectral signature of the light from the explosion. By virtue of the color signature, astronomers were able to prove it was a Type Ia supernova.

Read more at Science Daily

No Link Found Between Prenatal Exposure to Tobacco Smoke and Autism, Swedish Study Finds

A large population-based study in Sweden indicates that there is no link between smoking during pregnancy and autism spectrum disorders (ASD) in children. The study, led by Dr. Brian Lee, an assistant professor at Drexel University and a team of international collaborators, will appear in a forthcoming issue of the Journal of Autism and Developmental Disorders and was published online in December.

Researchers have considered a variety of chemical exposures in the environment during pregnancy and early life as possible contributing factors in the development of autism spectrum disorders. Many have considered prenatal exposure to tobacco smoke a possible cause due to known associations with behavioral disorders and obstetric complications. Past studies of maternal smoking and autism have had mixed results.

"We found no evidence that maternal smoking during pregnancy increases the risk of autism spectrum disorders," said Lee, an epidemiologist at Drexel's School of Public Health, who led the research in collaboration with researchers from Sweden's Karolinska Institute and the University of Bristol (Bristol, UK). "Past studies that showed an association were most likely influenced by social and demographic factors such as income and occupation that have associations with both the likelihood of smoking and with the rate of autism spectrum disorders."

In the new study, Lee and colleagues analyzed data from Swedish national and regional registries for a set of 3,958 children with autism spectrum disorders, along with a control set of 38,983 children born during the same period who did not receive an ASD diagnosis. Overall, 19.8 percent of the ASD cases were exposed to maternal smoking during pregnancy, compared to 18.4 percent of control cases. These rates showed an association between maternal smoking and the odds of an autism spectrum disorder, in unadjusted analyses. However, the association disappeared when the analysis was adjusted for sociodemographic factors such as the parents' income level, education, and occupation.

The report helps to reassure mothers who smoked during pregnancy that their behavior wasn't likely responsible for their child's autism, Lee said, and "crosses off another suspect on the list of possible environmental risk factors for ASD." He cautioned, however, that smoking during pregnancy is still unhealthy for mothers and has other known risks for their children.

Lee received his Ph.D. and M.H.S. degrees in Epidemiology from The Johns Hopkins University, and graduated Cum laude with an A.B. in Biological Anthropology from Harvard College. His research interests include the epidemiology of neurological development, maintenance and decline, including prenatal environmental exposures and autism risk; gene-environment interaction; and epidemiological methods including causal inference methodology, data mining and machine learning algorithms.

Read more at Science Daily

Evolution Is Written All Over Your Face

Why are the faces of primates so dramatically different from one another?

UCLA biologists working as "evolutionary detectives" studied the faces of 129 adult male primates from Central and South America, and they offer some answers in research published Jan. 11, in the early online edition of the journal Proceedings of the Royal Society B. The faces they studied evolved over at least 24 million years, they report.

"If you look at New World primates, you're immediately struck by the rich diversity of faces," said Michael Alfaro, a UCLA associate professor of ecology and evolutionary biology and the senior author of the study. "You see bright red faces, moustaches, hair tufts and much more. There are unanswered questions about how faces evolve and what factors explain the evolution of facial features. We're very visually oriented, and we get a lot of information from the face."

Some of theprimate species studied are solitary, while others live in groups that can include dozens or even hundreds of others.

The life scientists divided each face into 14 regions; coded the color of each part, including the hair and skin; studied the patterns and anatomy of the faces; and gave each a "facial complexity" score. They studied how the complexity of primate faces evolved over time and examined the primates' social systems. To assess how facial colors are related to physical environments, they analyzed environmental variables, using the longitude and latitude of primates' habitats as a proxy for sun exposure and temperature. They also used statistical methods to analyze the evolutionary history of the primate groups and when they diverged from one another.

"We found very strong support for the idea that as species live in larger groups, their faces become more simple, more plain," said lead author Sharlene Santana, a UCLA postdoctoral scholar in ecology and evolutionary biology and a postdoctoral fellow with UCLA's Institute for Society and Genetics. "We think that is related to their ability to communicate using facial expressions. A face that is more plain could allow the primate to convey expressions more easily.

"Humans have pretty bare faces, which may allow us to see facial expressions more easily than if, for example, we had many colors in our faces."

The researchers' finding that faces are more simple in larger groups came as a surprise.

"Initially, we thought it might be the opposite," Santana said. "You might expect that in larger groups, faces would vary more and have more complex parts that would allow one individual to identify any member of that group. That is not what we found. Species that live in larger groups live in closer proximity to one another and tend to use facial expressions more than species in smaller groups that are more spread out. Being in closer proximity puts a stronger pressure on using facial expressions."

"This finding suggests that facial expressions are increasingly important in large groups," said co-author Jessica Lynch Alfaro, associate director of the UCLA Institute for Society and Genetics. "If you're highly social, then facial expressions matter more than having a highly complex pattern on your face. "

The evolutionary biologists also found that when primates live in environment with more species that are closely related, their faces are more complex, regardless of their group size. This finding is consistent with their need to recognize individuals of other closely related species that live in the same habitat to avoid interbreeding, Santana said.

Santana, Lynch Alfaro and Alfaro present the first quantitative evidence linking social behavior to the evolution of facial diversity and complexity in primates, and they also show that ecology controls aspects of facial patterns.

As species live closer to the equator, the skin and hair around their eyes get darker, the biologists report. They also found that regions of the face around the nose and mouth get darker when species live in humid environments and denser forests and that facial hair gets longer as species live farther from the equator and the climate gets colder, which may be related to regulating body temperature.

"This is a good start toward understanding facial diversity," Alfaro said. "There was not a good idea before about what aspects of faces were shaped by which evolutionary pressure. Sharlene [Santana] has been able to say what social complexity, social behavior and ecology are doing to faces."

In the future, Santana, Lynch Alfaro and Alfaro may use computer facial-recognition software to help quantify the faces in a more sophisticated way. They also plan to study the faces of carnivores, including big cats.

Previous studies, they noted, have found that primate species with moustaches and beards (such as No. 11 and No. 9 in the accompanying image) tend to look poker-faced; they don't move their faces much when they communicate, compared with other species (such as No. 4).

Alfaro praised Santana's ability to answer some of these difficult evolutionary questions.

"Sharlene has tested ideas that have been virtually impossible to test before," he said. "She has found a clever way to implicate the degree of sociality as contributing to the diversity of faces. Social behavior explains some aspects of facial diversity."

Santana also devised a way to test a theory that has been in the biological literature for decades but had never been tested before. As a lineage diverges and species accumulate, a series of changes in facial coloration and body coloration emerges. The theory she was able to test suggests that once a species evolves to have a certain color, such as hair color, the change is irreversible and it cannot evolve back to a previous color in its lineage. Santana found this theory to be wrong.

"The idea in biology that evolutionary change is irreversible is rejected very strongly by our data," Alfaro said.

Read more at Science Daily

Thirteen Common (But Silly) Superstitions

If you are spooked by Friday the 13th, you're in for a whammy of a year. This week's unlucky day is the first of three for 2012. And it would come as no surprise if many among us hold at least some fear of freaky Friday, as we humans are a superstitious lot.

Many superstitions stem from the same human trait that causes us to believe in monsters and ghosts: When our brains can't explain something, we make stuff up. In fact, a 2010 study found that superstitions can sometimes work, because believing in something can improve performance on a task.

Here, then, are 13 of the most common superstitions.

13. Beginner's luck

Usually grumbled by an expert who just lost a game to a novice, "beginner's luck" is the idea that newbies are unusually likely to win when they try out a sport, game or activity for the first time.

Beginners might come out ahead in some cases because the novice is less stressed out about winning. Too much anxiety, after all, can hamper performance. Or it could just be a statistical fluke, especially in chance-based gambling games.

Or, like many superstitions, a belief in beginner's luck might arise because of confirmation bias. Confirmation bias is a psychological phenomenon in which people are more likely to remember events that fit their worldview. If you believe you're going to win because you're a beginner, you're more likely to remember all the times you were right -- "and forget the times you ended up in last place.

12. Find a penny, pick it up,,,

And all day long, you'll have good luck. This little ditty may arise because finding money is lucky in and of itself. But it might also be a spin-off of another old rhyme, "See a pin, pick it up/ and all day long you'll have good luck/ See a pin, let it lay/ and your luck will pass y."

11. Don't walk under that ladder!

Frankly, this superstition is pretty practical. Who wants to be responsible for stumbling and knocking a carpenter off his perch? But one theory holds that this superstition arises from a Christian belief in the Holy Trinity: Since a ladder leaning against a wall forms a triangle, "breaking" that triangle was blasphemous.

Then again, another popular theory is that a fear of walking under a ladder has to do with its resemblance to a medieval gallows. We're sticking with the safety-first explanation for this one.

10. Black cats crossing your path

As companion animals for humans for thousands of years, cats play all sorts of mythological roles. In ancient Egypt, cats were revered; today, Americans collectively keep more than 81 million cats as pets.

So why keep a black cat out of your path? Most likely, this superstition arises from old beliefs in witches and their animal familiars, which were often said to take the form of domestic animals like cats.

9. A rabbit's foot will bring you luck

Talismans and amulets are a time-honored way of fending off evil; consider the crosses and garlic that are supposed to keep vampires at bay. Rabbit feet as talismans may hark back to early Celtic tribes in Britain. They may also arise from hoodoo, a form of African-American folk magic and superstition that blends Native American, European and African tradition. [Rumor or Reality: The Creatures of Cryptozoology]

8. Bad luck comes in threes

Remember confirmation bias? The belief that bad luck comes in threes is a classic example. A couple things go wrong, and believers may start to look for the next bit of bad luck. A lost shoe might be forgotten one day, but seen as the third in a series of bad breaks the next.

7. Careful with that mirror

According to folklore, breaking a mirror is a surefire way to doom yourself to seven years of bad luck. The superstition seems to arise from the belief that mirrors don't just reflect your image; they hold bits of your soul. That belief led people in the old days of the American South to cover mirrors in a house when someone died, lest their soul be trapped inside.

Like the number three, the number seven is often associated with luck. Seven years is a long time to be unlucky, which may be why people have come up with counter-measures to free themselves after breaking a mirror. These include touching a piece of the broken mirror to a tombstone or grinding the mirror shards into powder.

6. 66

Three sixes in a row give some people the chills. It's a superstition that harks back to the Bible. In the Book of Revelation, 666 is given as the number of the "beast," and is often interpreted as the mark of Satan and a sign of the end times.

According to State University of New York at Buffalo anthropologist Philips Stevens, the writer of Revelation was writing to persecuted Christians in code, so the numbers and names in the book are contemporary references. Three sixes in a row is probably the numeric equivalent of the Hebrew letters for the first-century Roman Emperor Nero. [End of the World? Top Doomsday Fears]

5. Knock on wood

This phrase is almost like a verbal talisman, designed to ward off bad luck after tempting fate: "Breaking that mirror didn't bring me any trouble, knock on wood."

The fixation on wood may come from old myths about good spirits in trees or from an association with the Christian cross. Similar phrases abound in multiple languages, suggesting that the desire not to upset a spiteful universe is very common.

4. Make a wish on a wishbone

The tradition of turkey bone tug-of-war goes back a long way. Legend has it that first-century Romans used to fight over dried wishbones — which they believed were good luck — and would accidentally break them, ushering in the idea that whoever has the largest bit of bone gets their wish. Bird bones have also been used in divination throughout history, with a supposed soothsayer throwing the bones and reading their patterns to predict the future.

Read more at Discovery News

Jan 12, 2012

Bacteria's Move from Sea to Land May Have Occurred Much Later Than Thought

Research by University of Tennessee, Knoxville, faculty has discovered that bacteria's move from sea to land may have occurred much later than thought. It also has revealed that the bacteria may be especially useful in bioenergy research.

Igor Jouline, UT-Oak Ridge National Laboratory joint faculty professor of microbiology and researcher at ORNL's Joint Institute for Computational Sciences, performed a genome sequence analysis of the soil bacteria Azospirillum, a species' whose forebearers made the sea-to-land move. The analysis indicates the shift may have occurred only 400 million years ago, rather than approximately two billion years earlier, as originally thought.

Published in the journal PLoS Genetics, Jouline calculated the timing of the sea-land transition through studies of genome sequences of two species of Azospirillum, a terrestrial genus with almost exclusively aquatic relatives.

Jouline conducted his research with Kristin Wuichet and Leonid Sukharnikov of the Department of Microbiology, Gladys Alexandre of Department of Biochemistry, Cellular, and Molecular Biology, and Kirill Borziak, a graduate student in the ORNL-UT Genome Science and Technology program.

"In the absence of fossil records for bacteria, it is hard to estimate when and how bacteria transitioned from sea to land," said Jouline. "Using genome sequencing and analysis of bacteria of the genus Azospirillum, which colonizes roots of important cereals and grasses, we show that these organisms transitioned from aquatic environments to land approximately at the same time that plants appeared on land -- 400 million years ago."

Jouline said the Azospirillum lineage the team studied has obtained nearly half of its genome from terrestrial organisms, which suggests the much later water-land transition, which coincides with the first appearance of plants on land.

The study is of interest to researchers beyond its evolutionary significance. Azospirillum is currently used as a biofertilizer for grasses and some other plants. Commercial fertilizers containing the bacteria are available world wide.

"Because these bacteria colonize roots of grasses and improve their growth and development, they might be important for bioenergy research," Jouline said.

"Switchgrass is one of the most important potential sources of bioethanol. In this study, we have shown that genomes of Azospirillum contain as many cellulolytic enzymes as those from known effective cellulose degrading bacteria," he said. "We have also demonstrated experimentally that azospirilla do degrade cellulose, especially the strain that can penetrate grass roots."

Read more at Science Daily

World's Smallest Hard Drive Built of Atoms

Hard drives could one day be the size of rice grains, powering music players so small they would fit inside your ear.

Scientists at IBM and the German Center for Free-Electron Laser Science have built the world's smallest unit of magnetic storage, using just 96 atoms to create one byte of data. Conventional drives require a half a billion atoms for each byte.

The advance could lead to tiny hard drives able to store 200 to 300 times more information than they can today. Just imagine an iPod Touch that held 12.8 terabytes of music.

"An effect that is common in nature can produce this information storage idea," said Sebastian Loth of CFEL, lead author of the research, which is being published today in the journal Science.

The natural phenomenon Loth is referring to has to do with the way electrons spin inside an atom. Modern hard drives rely on magnetic materials such as iron, where electrons all spin in the same direction perfectly aligned with each other. The drives work by reading the magnetic states of small regions on a disk and using an external field to write to them.

But these so-called ferromagnetic materials can only be shrunk down so far. If the magnetic regions get too close to each other, their magnetic fields interfere with each other and make it difficult to accurately store data.

"This is a big problem if you want to pack in the magnetic density," said Loth.

But with materials that are not magnetic, known as antiferromagnetic materials, the electrons spin in opposite directions from one another and are magnetically neutral.

"Antiferromagnetic regions don't have a magnetic field so you can pack them closer," Loth said.

In fact, the scientists were able to squeeze bits into a space just one nanometer apart.

The team assembled the tiny hard drive from the atom up, using a special tool known as scanning tunneling microscope, or STM. They carefully placed atoms into rows of six atoms each. Two rows were enough to store one bit of information. Eight pairs of rows amounted to one byte of data.

Each pair of rows has two possible magnetic states, representing the classical 0 and 1 of binary computer data. An electric pulse from the STM tip flips the magnetic configuration from one to the other. A weaker pulse was used to read it.

"What this shows is you have all the ingredients for storing information on an antiferromagnetic grain," said Matthias Bode, an experimental physics professor at the University of Würzburg, who was not involved in the research.

It will be some time before this technology is used in a hard drive for a computer, as there are a few problems that still have to be overcome. First, this hard drive was built atom-by-atom, using an STM -- an impractical and slow method for manufacturing.

Secondly, the storage of the information -- the magnetic state -- is only stable at very cold temperatures, about 5 degrees above absolute zero. Warmer than that and the spins of the atoms get jostled.

Bode said that finding a material that works at room temperature isn't impossible. What material will work, however, remains to be seen.

Read more at Discovery News

'Saturn on Steroids' Exoplanet Discovered?

By analyzing the silhouette of an exoplanet passing in front of its parent star 420 light-years away, astronomers have discovered what may be a large gas giant world sporting a ring system. Could it be Saturn's twin?

The star in question is called 1SWASP J140747.93-394542.6 and astronomers spent 54 days in 2007 watching its brightness change in a rather curious way.

Exoplanet observatories have a few methods they can apply to observe worlds orbiting distant stars, but in the case of 1SWASP J140747.93-394542.6 the orbiting exoplanet was spotted as it drifted in front, blocking a portion of the star's light from view.

This in itself isn't unheard of -- after all, NASA's Kepler space telescope has spotted hundreds of candidate exoplanets using this "transit method" -- but the way in which the starlight dimmed was peculiar.

The as the star's brightness changed over time, its "light curve" exhibited a strange pattern. Rather than smoothly dimming and then brightening as a spherical exoplanet drifted past the star's disk (as would normally be expected), its brightness dramatically fluctuated.

Using data from the SuperWASP (Wide Angle Search for Planets) project and All Sky Automated Survey (ASAS), University of Rochester astronomer Eric Mamajek and graduate student Mark Pecaut spotted another unusual dimming event in December 2010.

"When I first saw the light curve, I knew we had found a very weird and unique object," said Mamajek. "After we ruled out the eclipse being due to a spherical star or a circumstellar disk passing in front of the star, I realized that the only plausible explanation was some sort of dust ring system orbiting a smaller companion -- basically a 'Saturn on steroids.'"

As this particular exoplanet passed in front of its parent star, it would appear Mamajek and Pecaut were observing the Saturn-like rings pass in front of the star as well as the world itself. The discrete structures within the exoplanets ring system caused dramatic fluctuations in star brightness as the transit progressed -- starlight flickering as it passed through the ring structures. At some points of the ring transit, 95 percent of starlight was blocked by the dust.

"This marks the first time astronomers have detected an extrasolar ring system transiting a Sun-like star, and the first system of discrete, thin, dust rings detected around a very low-mass object outside of our solar system," said Mamajek, "But many questions remain about what exactly has been discovered."

It's possible that the object in the center of the ring system is either a very low-mass star, brown dwarf, or gas giant planet. To arrive at this answer, they hope to follow up with radial velocity measurements of the star's motion.

Read more at Discovery News

Russian Quasicrystals Might Come From Space

An unusual type of rock known as a quasicrystal was found deep in the Russian mountains in 2010. Now scientists think it may have come from outer space, and dates back to the earliest days of our solar system.

If you followed news of last year's Nobel Prize in Chemistry, you heard about quasicrystals, an unusual type of material first described in the 1980s by Israeli scientist Daniel Schechtman. A quasicrystal has a strange atomic structure that gives it unique properties, falling somewhere between a true crystal and glass.

Schechtman found them quite by accident, while on sabbatical in the US. He was working with rapidly cooled alloys of aluminum and manganese, and noticed an unusual pattern in the electrondiffraction pattens they produced. Per this 2003 article in APS News:

"In normal crystals, atoms lie on three-dimensional lattices of cells. Each cell has an identical pattern of cells surrounding it. In a quasicrystal, he local arrangements of atoms are fixed, but each cell has a different configuration of cells nearby. Although the structures are strikingly similar to the quasiperiodic tilings invented by mathematician Roger Penrose ... there was little in the crystallographic field to presace the experimental breakthrough."

Schechtman was famously ridiculed for his ideas when he first proposed them -- he had great difficulty getting his discovery published in a peer-reviewed science journal for the first two years -- but eventually it appeared in Physical Review Letters.

And in one of the best scientific underdog stories of recent memory, he proved correct, sparking a revolution in crystallography. That paper is now one of the ten most cited articles in the history of the journal. Today synthetic quasicrystals are used to strengthen steel or aluminum, or to create a coating with properties similar to Teflon.

People also speculated about naturally occurring quasicrystals, and finally geologists discovered just that while studying rocks in Russian's Koryak mountains. But a new paper by Princeton University's Paul Steinhardt, claims those naturally occurring quasicrystals have a far more exotic origin: they fell to Earth in meteorites from outer space.

Steinhardt and his team decided to start scanning databases of crystals in 1998 "to see if nature found ones that have not yet been discovered synthetically by trial and error," according to Steinhardt. Using x-ray and electron diffraction imaging techniques, the scientists searched for any crystals that had patterns indicative of quasicrystals.

It took eight long years, but finally, in 2007, they sifted through a collection belonging to Luca Bindi of the University of Florence, which included a rock found in the Koryak Mountains. An alloy of aluminum, copper and iron, Its pattern clearly made it a quasicrystal.

A mass spectroscopy analysis of the Russian rock's structure revealed unusual ratios of oxygen atoms and their isotopes, matching the ratios typically found inside a certain type of meteorite known as a carbonaceous chondrite. The samples also contained silica, suggesting it had formed under high pressure conditions.

Read more at Discovery News

Jan 11, 2012

Global Warming May Make Reptiles Smarter

As climate change alters the temperatures of reptile habitats around the globe, tests of one lizard species suggests warmer nests could make some reptiles smarter.

When researchers incubated the eggs of Bassiana duperreyi, a mountain-dwelling Australian skink, at warmer-than-usual temperatures, they grew up to perform especially well on a learning task.

Herpetologists knew reptiles incubated in warmer nests developed differently, but linking hotter egg temperatures to increased intelligence is a first.

“We have 16 to 17 years of data on the effects of incubation temperature on skinks. We know the hotter guys are bigger, faster, absorb more [egg] yolk,” said herpetologist Joshua Amiel of the University of Sydney, whose research was published Jan. 11 in Biology Letters. “But hardly anyone has given a look at the effect on reptile learning.”

Reptiles are cold-blooded animals. Unlike mammals or birds, which burn through calories to maintain body temperature, they use sunlight or other environmental sources of heat.

Because reptiles rely so much on environmental temperatures to survive, researchers have wondered how temperature affects their early development.

Cooler incubation temperatures in the Eastern three-lined skink, for example, produce smaller, less-agile hatchlings that are more likely to be male. Similar effects are seen in turtles. In crocodiles, extremes of temperature produce more females.

Thanks to their reduced metabolism and lumbering, sun-bathing behaviors, reptiles are rarely viewed as intelligent animals. Research on their mental ability, much less the effects of climate upon it, is lacking.

Amiel and colleague Richard Shine developed a simple predator avoidance test: At each end of a rectangular tub, they placed an upside-down flower pot into which skinks could run and hide. The entrance to one pot was blocked by clear plastic.

After incubating two different sets of eggs at different temperatures — the warmer set mimicking natural incubation settings of skinks at lower elevations, the cooler set mimicking higher elevations — Amiel and Shine tested the hatchlings.

They sent each lizard running by touching its tail, then measured how long it took to find the open shelter and how often it tried to enter the blocked door. Warm-incubated lizards learned to find the open flower pot much more readily than their cool-incubated siblings. In the wild, improved learning abilities likely increase chances of survival.

Read more at Wired Science

Milky Way Crammed With 100 Billion Alien Worlds?

Last year, using the exoplanets discovered by the Kepler space telescope as a guide, astronomers took a statistical stab at estimating the number of exoplanets that exist in our galaxy. They came up with at least 50 billion alien worlds.

Today, astronomers from the Space Telescope Science Institute (STScI) in Baltimore, Md., and the PLANET (Probing Lensing Anomalies NETwork) collaboration have taken their own stab at the "galactic exoplanetary estimate" and think there are at least 100 billion worlds knocking around the Milky Way.

Why has the estimate doubled? The key difference here are the methods used to detect alien worlds orbiting distant stars.

The Kepler space telescope watches the same patch of sky -- containing around 100,000 stars -- and waits for slight "dips" in starlight brightness. This dip occurs when an exoplanet passes in front of its parent star, thereby blocking a tiny fraction of light from view.

This slight dimming effect is known as a "transit" and when four transits are detected by Kepler, the announcement of a confirmed exoplanet can be made.

The "transit method" has proven itself to be an excellent way of spotting exoplanets, but the method favors the detection of large exoplanets and exoplanets that orbit close to their stars. Pretty obvious really; the closer or the larger the exoplanet, the more starlight can be blocked and the bigger the "dip."

However, to arrive at their "galactic exoplanetary estimate" the PLANET team employed a rather different (and more random) exoplanet detection method known as "microlensing."

Microlensing depends on a lot of patience and a lot of luck, but given enough time and enough stars, exoplanets can be discovered this way.

From our perspective, as stars drift around the sky, occasionally one star will drift in front of another. The starlight from the more distant star may become bent around the foreground star by its gravity, causing the light from the background star to brighten for a short period of time.

The foreground star has basically acted as a magnifying lens, focusing the light from the background star for astronomers on Earth to observe. The more massive the star, the longer the brightening event.

This is where the clever bit comes in. Should the foreground star have an exoplanet (or a system of exoplanets) in orbit, its additional gravity will create another brightening event, thereby allowing astronomers on Earth to measure the exoplanet's mass and orbit.

Typically, the microlens brightening caused by the star will last about a month and the brightening caused by the presence of an exoplanet will only last a few hours.

Microlensing events are random occurrences and don't depend on star selection. Also, the method can detect exoplanets as small as Mercury and exoplanets orbiting as far from their host star as Saturn orbits the sun. Kepler's transit detection method favors the detection of worlds orbiting close to their stars, whereas microlensing has no such restriction.

So, when the PLANET collaboration detected 40 microlensing events, and noted that three contained exoplanets, they could do a statistical analysis to estimate the number of stars that have exoplanets in our galaxy.

From this analysis, the PLANET team made a rough estimate of 100 billion exoplanets living in our galaxy. Additionally, they found that one-in-six stars host a Jupiter-mass exoplanet, half the stars in the Milky Way have Neptune-mass exoplanets and two-thirds of the stars have Earth-mass worlds.

Interestingly, this result points to least 1,500 exoplanets within 50 light-years from the solar system.

As already uncovered by the Kepler science team, smaller worlds appear to dominate our galaxy -- the PLANET collaboration supports this idea.

Read more at Discovery News

Ancient Mayans Enjoyed a Hallucinogenic Concoction

Archaeologists have found traces of nicotine in a 1,300-year-old vessel, revealing the first physical evidence of tobacco use by the Mayans.

Made around 700 A.D. in the region of the Mirador Basin, in Southern Campeche, Mexico, during the Classic Mayan period, the two-and-a-half-inch wide and high clay vessel was a "house of tobacco," as indicated by hieroglyphic texts. They read: “y-otoot ’u-may,” (“the home of its/his/her tobacco,”) .

"This is only the second case in which residue analysis shows a Mayan vessel to have had the same content as indicated by hieroglyphics," Jennifer Loughmiller-Newman, from the University at Albany in New York, told Discovery News.

The last discovery occurred more than 20 years ago and involved a vessel containing cacao.

Loughmiller-Newman and Dmitri Zagorevski from the Rensselaer Polytechnic Institute in Troy, New York analyzed residues from more than 50 various Mayan vessels, mainly from the Kislak collection of the Library of Congress.

"None of them, as of now, have shown any traces of nicotine or other alkaloids," the researchers wrote in the journal Rapid Communications in Mass Spectrometry.

Indeed, several issues, such as bacteria, contamination, and the fact that the usage of containers changed over time, often limit the success of chemical analysis on ancient residues.

Nevertheless, Loughmiller-Newman and Zagorevski were able to find the chemical fingerprint of tobacco in the codex-style flask.

The identification was performed by using two analytical chemistry tecniques -- gas chromatography mass spectrometry (GCMS) and liquid chromatography mass spectrometry (LCMS).

"Both methods resulted in the positive identification of nicotine," said the researchers.

In addition, three oxidation products of nicotine, indicating natural processes of bacterial degradation, were discovered.

None of the nicotine byproducts associated with the smoking of tobacco was detected, likely ruling out the use of the vessel as an ash tray.

"The tobacco found in that container was probably not used for smoking. It was likely a powered product," Loughmiller-Newman said.

According to the researcher, the tobacco known to the ancient Mayas "was far stronger than any plant grown today and possibly strong enough to be hallucinogenic."

Likely mixed with lime, the powered tobacco from the vessel would have been chewed, consumed as snuff or added to alcohol for stronger drinks.

Read more at Discovery News

Fearsome Dino Had Funny Arms

With its blade-like teeth and formidable claws, Majungasaurus crenatissimus was one of the world’s most fearsome predators, but new research reveals that it also possessed some of the animal kingdom's smallest and most peculiar arms.

The giant, cannibalistic dinosaur had such disproportionate arms that it could not have grasped anything or even scratched its own face, according to a new study published in the Journal of Vertebrate Paleontology.

Tyrannosaurus rex and other well known predatory dinosaurs also had reduced forelimbs. While Majungasaurus, which lived 66 million years ago in Madagascar, was not a close T. rex relative, some lifestyle factors might have caused them to evolve certain similarities.

"The evolution of short arms in predatory dinosaurs remains a mystery, but fossils like this are an important clue in understanding the process," co-author Matthew Carrano, a paleobiologist at the Smithsonian Institution, told Discovery News.

"Only by discovering the stops leading from 'normal' longer arms in the ancestral forms, to the short and bizarre ones in Majungasaurus and its close relatives, can we hope to explain the evolutionary sequence and its causes."

Carrano and co-author Sara Burch of Stony Brook University analyzed the arm and associated fossils for a new specimen of the Late Cretaceous dinosaur. They concluded that the arm proportions "are unlike anything we see in other theropods."

The forearm bones are only a quarter of the length of the upper arm bones, but would have been thick and muscular. The wrist bones, however, aren't even ossified, and the stubby fingers probably lacked claws.

"The bones of the hand are so small that the fingers may not have even been separated from each other, which means the hand could have been almost paddle-like," Burch told Discovery News.

The result was an arm that was part Popeye and part Barbie. The researchers have no idea what function the arms served.

The forelimbs might have just been stuck at a transitional point in their evolution. If non-avian dinosaurs did not all bite the dust at the end of the Cretaceous, Majungasaurus might have evolved into an enormous ostrich-like animal without arms, but with very strong legs.

“It is possible that with such large heads full of teeth, some large predatory dinosaurs no longer needed to use their forelimbs to aid in capturing prey, so the forelimbs became smaller as they lost this function,” Burch explained.

During its lifetime, Majungasaurus was about 21 feet long and had a muscular neck, legs, and tail. It held the distinction of being the top predator in its territory. Based on fossils bearing its tooth marks, Majungasaurus feasted on enormous long-necked sauropods and didn’t shy away from biting into members of its own species.

Read more at Discovery News

Jan 10, 2012

Molecular 'Culprit' in Rise of Planetary Oxygen

A turning point in the history of life occurred 2 billion to 3 billion years ago with the unprecedented appearance and dramatic rise of molecular oxygen. Now researchers report they have identified an enzyme that was the first -- or among the first -- to generate molecular oxygen on Earth.

The new findings, reported in the journal Structure, build on more than a dozen previous studies that aim to track the molecular evolution of life by looking for evidence of that history in present-day protein structures. These studies, led by University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-Anollés, focus on structurally and functionally distinct regions of proteins -- called folds -- that are part of the universal toolkit of living cells.

Protein folds are much more stable than the sequences of amino acids that compose them, Caetano-Anollés said. Mutations or other changes in sequence often occur without disrupting fold structure or function. This makes folds much more reliable markers of long-term evolutionary patterns, he said.

In the new study, Caetano-Anollés, working with colleagues in China and Korea, tackled an ancient mystery: Why did some of the earliest organisms begin to generate oxygen, and why?

"There is a consensus from earth scientists that about 2.4 billion years ago there was a big spike in oxygen on Earth," Caetano-Anollés said. They generally agree that this rise in oxygen, called the Great Oxygenation Event, was tied to the emergence of photosynthetic organisms.

"But the problem now comes with the following question," he said. "Oxygen is toxic, so why would a living organism generate oxygen? Something must have triggered this."

The researchers looked for answers in the "molecular fossils" that still reside in living cells. They analyzed protein folds in nearly a thousand organisms representing every domain of life to assemble a timeline of protein history. Their timeline for this study was limited to single-fold proteins (which the researchers believe are the most ancient), and was calibrated using microbial fossils that appeared in the geologic record at specific dates.

The analysis revealed that the most ancient reaction of aerobic metabolism involved synthesis of pyridoxal (the active form of vitamin B6, which is essential to the activity of many protein enzymes) and occurred about 2.9 billion years ago. An oxygen-generating enzyme, manganese catalase, appeared at the same time.

Other recent studies also suggest that aerobic (oxygen-based) respiration began on Earth 300 to 400 million years before the Great Oxidation Event, Caetano-Anollés said. This would make sense, since oxygen production was probably going on for a while before the spike in oxygen occurred.

Catalases convert hydrogen peroxide to water and oxygen. The researchers hypothesize that primordial organisms "discovered" this enzyme when trying to cope with an abundance of hydrogen peroxide in the environment. Some geochemists believe that hydrogen peroxide was abundant at this time as a result of intensive solar radiation on glaciers that covered much of Earth.

Read more at Science Daily

How the Brain Spots Faces

Our brains are made to find faces. In fact, they’re so good at picking out human-like mugs we sometimes see them in a jumble of rocks, a bilious cloud of volcanic ash or some craters on the Moon.

But another amazing thing about our brain is that we’re never actually fooled into thinking it’s a real person looking back at us. We might do a second take, but most normal brains can tell the difference between a man and the Moon.

Neuroscientists from the Massachusetts Institute of Technology wanted to investigate how the brain decides exactly what is and is not a face. Earlier studies have shown that the fusiform gyrus, located on the brain’s underside, responds to face-like shapes — but how does it sort flesh from rock?

Pawan Sinha, professor of brain and cognitive sciences at MIT, and students created a procession of images ranging from those that look nothing like faces to genuine faces. For the ones in the middle — structures, formations, smudges and shapes that give us a pareidolic reaction that causes us to see a face — they used photographs that machine vision systems had falsely tagged as faces.

By doing a series of one-to-one comparisons, the human observers rated how face-like each of the images were. And while the subjects sorted out the photographs, functional magnetic resonance imaging (fMRI) was used to scan their brains and look for activity.

The neuroscientists found different activity patterns on each side of the brain. On the left, the activity patterns changed very gradually as images became more like faces and there was no clear distinction between faces and non-faces. The left side would flare if someone was looking at a human or an eerily face-like formation of rocks.

But on the right side, activation patterns in the fusiform gyrus were completely different between genuine human faces and face-like optical illusions. There was no fooling the right side of the brain, no matter how much they resembled a face.

The researchers could conclude that the left side of the brain ranks images on a scale of how face-like they are.The right side makes the categorical distinction whether or not it’s a human face.

The left side of the fusiform gyrus actually flared up before the right side supporting the hypothesis that the left side does its job first and then passes information on to the right side. (Though because of the sluggishness of fMRI signals, which rely on blood-flow changes, the timing does not yet constitute definitive evidence).

“The left does the initial heavy lifting,” Sinha says. “It tries to determine how face-like is a pattern, without making the final decision on whether I’m going to call it a face.” The right’s job is to make the final call.

Read more at Wired Science

Ancient Menorah Stamped Kosher Bread

A tiny stamp bearing an image of the Temple Menorah and likely placed on baked goods some 1,500 years ago has turned up during excavations near the Israeli city of Akko, researchers announced.

The Israel Antiquities Authority discovered the ceramic stamp while excavating at Horbat Uza, a small rural settlement east of the city Akko, before construction of a railroad track connecting Akko and Karmiel in northern Israel.

From the Byzantine period, the stamp is called a "bread stamp," as it was used to identify baked goods; this one, in particular, probably belonged to a bakery supplying kosher bread to the Jews of Akko, the researchers say.

Engraved into the stamp is the seven-branched menorah on top of a narrow base. Several Greek letters appear around a circle and dot, all of which are engraved on the end of the menorah's handle. The researchers suggest the letters spell out the name Launtius, a common name among Jews of this period and a name that has shown up on other bread stamps. Launtius was likely the name of the baker, they added. [Photos of stamp & excavation]

"A potter engraved the menorah image in the surface of the stamp prior to firing it in a kiln, whereas the owner's name was engraved in the stamp's handle after firing," said David Amit of the Israel Antiquities Authority who studies bread stamps. "Hence we can assume that a series of stamps bearing the menorah symbol were produced for Jewish bakers, and each of these bakers carved his name on the handle, which also served as a stamp."

The stamp would have been used to label the dough with the baker's name.

The image of the seven-branched Temple Menorah supports the idea that it belonged to the Jews, as Christian bread stamps tend to have a cross pattern on them — the Christian type was more common during the Byzantine, according to Gilad Jaffe, one of the excavation directors for the Israel Antiquities Authority.

Read more at Discovery News

Galactic Cluster Clash Spotted in Early Universe

Say hello to "El Gordo," one of the biggest cosmic collisions you will ever witness.

Radiating brightly in X-ray and infrared emissions, El Gordo -- meaning "the big one" or "the fat one" in Spanish, a nickname given to the object by astronomers -- is two galactic clusters smashing into one another 7 billion light-years away.

However, the term "smashing into one another" isn't entirely accurate. Indeed, the two clusters of galaxies are going through a head-on collision, and they are ploughing through space at a breakneck speed of several millions of miles per hour, but few (if any) of the stars contained within the galaxies inside the clusters will physically collide.

There is a lot of space between the galaxies and stars, so they'll simply whiz past one another -- but the gravitational turmoil caused by these two clusters colliding is fierce and interactions between the shocked gas and dust are dazzlingly beautiful.

"This cluster is the most massive, the hottest, and gives off the most X-rays of any known cluster at this distance or beyond," said Felipe Menanteau of Rutgers University in New Brunswick, N.J., who led the study.

But there's also an invisible battle unfolding inside this cosmic Clash of the Titans: vast clouds of dark matter -- the stuff that makes up over 80 percent of the entire mass of the universe -- are blasting through the colliding clusters resembling a cloud of angry bees swarming around a hive.

Though the dark matter particles do not interact with normal matter (they cut through all the clouds of gas and dust seen in this image as if they didn't exist), the gravitational effects of dark matter on normal matter can be studied. And it is huge colliding clusters like El Gordo that are so valuable to astronomers.

"Gigantic galaxy clusters like this are just what we were aiming to find," said team member Jack Hughes, also from Rutgers University. "We want to see if we can understand how these extreme objects form using the best models of cosmology that are currently available."

The discovery of this colliding cluster 7 billion light-years away is the furthest known example. As it took 7 billion years for its light to travel to Earth, the collision actually happened when the Universe was only half the age it is now (13.75 billion years old). The famous "Bullet Cluster," another pair of colliding clusters used by astronomers to study dark matter, is located much closer -- at 4 billion light-years distant.

Read more at Discovery News

Jan 9, 2012

Hatcheries Change Salmon Genetics After a Single Generation

The impact of hatcheries on salmonids is so profound that in just one generation traits are selected that allow fish to survive and prosper in the hatchery environment, at the cost of their ability to thrive and reproduce in a wild environment.

The findings, published this week in Proceedings of the National Academy of Sciences, show a speed of evolution and natural selection that surprised researchers.

They confirmed that a primary impact of hatcheries is a change in fish genetics, as opposed to a temporary environmental effect.

"We've known for some time that hatchery-born fish are less successful at survival and reproduction in the wild," said Michael Blouin, a professor of zoology at Oregon State University. "However, until now, it wasn't clear why. What this study shows is that intense evolutionary pressures in the hatchery rapidly select for fish that excel there, at the expense of their reproductive success in the wild."

Hatcheries are efficient at producing fish for harvest, the researchers said, but this and other studies continue to raise concerns about the genetic impacts that hatchery fish may have when they interbreed with wild salmon and steelhead, and whether or not they will help wild salmonid runs to recover.

These findings were based on a 19-year genetic analysis of steelhead in Oregon's Hood River. It examined why hatchery fish struggle to reproduce in wild river conditions, a fact that has been made clear in previous research. Some of the possible causes explored were environmental effects of captive rearing, inbreeding among close relatives, and unintentional "domestication selection," or the ability of some fish to adapt to the unique hatchery environment.

The study confirmed that domestication selection was at work.

When thousands of smolts are born in the artificial environment of a hatchery, those that survive best are the ones that can deal, for whatever reason, with hatchery conditions. But the same traits that help them in the hatchery backfire when they return to a wild river, where their ability to produce surviving offspring is much reduced.

"We expected to see some of these changes after multiple generations," said Mark Christie, an OSU post-doctoral research associate and lead author on the study. "To see these changes happen in a single generation was amazing. Evolutionary change doesn't always take thousands of years."

It's not clear exactly what traits are being selected for among the thousands of smolts born in hatcheries, the scientists said, but one of the leading candidates is the ability to tolerate extreme crowding. If research can determine exactly what aspect of hatchery operations is selecting for fish with less fitness in the wild, it could be possible to make changes that would help address the problem, they said.

Historically, hatchery managers preferred to use fish born in hatcheries as brood stock to create future generations, because whatever trait they had that allowed them to succeed in the hatchery helped produce thousands of apparently healthy young salmon. But they later found that when those same fish were released they had a survival and reproductive success that was far lower than those born in the wild.

Billions of captive-reared salmon are intentionally released into the wild each year in order to increase fishery yields and bolster declining populations. The steelhead studied in this research are, in fact, listed as threatened under the Endangered Species Act, and part of their recovery plan includes supplementation with hatchery fish.

"It remains to be seen whether results from this one study on steelhead generalize to other hatcheries or salmon species," Blouin said.

Read more at Science Daily

Scientists Discover a Saturn-Like Ring System Eclipsing a Sun-Like Star

A team of astrophysicists from the University of Rochester and Europe has discovered a ring system in the constellation Centaurus that invites comparisons to Saturn.

The scientists, led by Assistant Professor of Physics and Astronomy Eric Mamajek of Rochester and the Cerro Tololo Inter-American Observatory, used data from the international SuperWASP (Wide Angle Search for Planets) and All Sky Automated Survey (ASAS) project to study the light curves of young Sun-like stars in the Scorpius-Centaurus association -- the nearest region of recent massive star formation to the Sun.

The basic concept of the research is straightforward. Imagine yourself sitting in a park on a sunny afternoon and a softball passes between you and the sun. The intensity of light from the sun would appear to weaken for just a moment. Then a bird then flies by, causing the intensity of the sunlight to again weaken -- more or less than it did for the baseball, depending on the size of the bird and how long it took to pass. That's the principle that allowed the researchers to discover a cosmic ring system.

A light curve is a graph of light intensity over time, and one star in particular showed dramatic changes during a 54 day period in early 2007. University of Rochester graduate student Mark Pecaut and Mamajek discovered the unusual eclipse in December 2010. "When I first saw the light curve, I knew we had found a very weird and unique object. After we ruled out the eclipse being due to a spherical star or a circumstellar disk passing in front of the star, I realized that the only plausible explanation was some sort of dust ring system orbiting a smaller companion -- basically a 'Saturn on steroids,'" said Mamajek.

If a spherical object merely passed in front of the star, the intensity of the light would gradually dim and reach a low point before gradually increasing. That was not the case with the star identified as 1SWASP J140747.93-394542.6. The Rochester team discovered a long, deep, and complex eclipse event with significant on-and-off dimming. At the deepest parts of the eclipse, at least 95% of the light from the star was being blocked by dust.

The shape of the light curve was very similar to that of a well-researched star (EE Cephei), suggesting similar traits in the companion objects. However EE Cephei differs in that it appears to be a thick protoplanetary disk transiting -- or passing -- in front a massive, hot star. "We suspect this new star is being eclipsed by a low-mass object with an orbiting disk that has multiple thin rings of dust debris," said Mamajek. The star is similar in mass to the sun, but is much younger -- about 16 million years old or 1/300th the age of the solar system -- and it lies about 420 light years away.

The research was conducted by Mamajek, Associate Professor Alice Quillen, graduate student Mark Pecaut, graduate student Fred Moolekamp, and graduate student Erin Scott of Rochester; Assistant Professor Matthew Kenworthy of Leiden University in The Netherlands; and Professor Andrew Collier Cameron and postdoctoral research assistant Neil Parley of the University of St. Andrews in Scotland. Their findings will be published in an upcoming issue of the Astronomical Journal.

"This marks the first time astronomers have detected an extrasolar ring system transiting a Sun-like star, and the first system of discrete, thin, dust rings detected around a very low-mass object outside of our solar system," said Mamajek, "But many questions remain about what exactly has been discovered." He says the object at the center of the ring system is either a very low-mass star, brown dwarf, or planet. The answer lies in the object's mass.

In order to be a brown dwarf, the object would have to be between 13 MJ (Jupiter masses) and 75 MJ, insufficient to sustain the thermonuclear fusion reactions during its projected lifetime. If the object's mass is less than 13 MJ, it would likely be a planet, making it similar to Saturn whose rings have a similar optical depth.

Mamajek and colleagues will be proposing to use southern hemisphere telescopes to obtain radial velocity data for the star to detect the gravitational tug of the companion, and conduct non-redundant mask imaging experiments to try to detect light from the faint companion. The observations will help calculate the companion's mass, which, in turn, will help determine its identity.

Along with the central object, Mamajek is interested in what is taking place in the two pronounced gaps located between the rings. Gaps usually indicate the presence of objects with enough mass to gravitationally sculpt the ring edges, and Mamajek thinks his team could be either observing the late stages of planet formation if the transiting object is a star or brown dwarf, or possibly moon formation if the transiting object is a giant planet.

If the dusty rings are similar to Saturn's in terms of their mass per optical depth, then the total mass of the rings is only on the order of the mass of Earth's moon. The orbital radius of the outermost ring is tens of millions of kilometers, so the mass and size of the ring systems is substantially heftier than Saturn's ring system. In the discovery paper, the four rings detected thus far have been dubbed "Rochester," "Sutherland," "Campanas," and "Tololo" after the sites where the eclipsed star was first detected and analyzed.

Read more at Science Daily

What is dark matter?

Incredible as it may sound planets, stars and everything else we can see in space only accounts for about four per cent of the matter in the Universe.

Up to 90 per cent is believed to be comprised of dark matter, a substance which is invisible but can be inferred through its gravitational force which holds galaxies together.

Despite being theorised almost 80 years ago, dark matter still remains deeply mysterious because it can not be detected directly.

Scientists believe that huge clumps of the stuff are spread throughout space where their gravitational fields attract what we know as normal matter.

Eventually this normal matter condenses into galaxies of stars and planets, making dark matter in effect the glue that holds the Universe together.

Learning more about the matter, which likely consists of various different types of particle performing different roles, could shed light on some of the most fundamental questions in science.

If it did not exist, as some scientists believe, we would need a new explanation for how Earth and everything else in the Universe was formed.

From The Telegraph

Vast Web of Dark Matter Mapped

Astronomers have created a vast cosmic map revealing an intricate web of dark matter and galaxies spanning a distance of one billion light-years.

This unprecedented task was achieved not by observing dark matter directly, but by observing its gravitational effects on ancient light traveling from galaxies that existed when the Universe was half the age it is now.

Constructed by astronomers from the University of British Columbia and University of Edinburgh, this is the largest dark matter map ever built and took five years to complete.

The research was presented at the American Astronomical Society meeting in Austin, Texas, on Monday.

Dark matter pervades the entire observable universe, accounting for 83 percent of the mass of the cosmos. But as it does not scatter or radiate light (or any kind of electromagnetic radiation for that matter), we cannot see it. Naturally, this poses an interesting problem for astronomers hoping to map the stuff.

However, astronomers can indirectly observe dark matter as its mass exerts a gravitational force on the space-time surrounding it. As light travels from distant galaxies, it will be bent around gravitational distortions in space-time -- much like the paths of marbles rolling across a bent sheet of plastic -- being caused by the dense regions of dark matter.

With this in mind, the international team of astronomers analyzed light from 10 million galaxies in four different regions of the sky -- all of which are around 6 billion light-years from Earth. As these galaxies are six billion light-years away, it took the light six billion years to travel that distance.

Using a 340 Megapixel camera called "MegaCam" attached to the Canada-France-Hawaii Telescope (CFHT) in Hawaii, the ancient galactic light was analyzed to reveal the distorted paths each source traveled thereby revealing the gravitational terrain surrounding clouds of dark matter.

"It is fascinating to be able to 'see' the dark matter using space-time distortion," said Ludovic Van Waerbeke from the University of British Columbia.

"It gives us privileged access to this mysterious mass in the Universe which cannot be observed otherwise."

Catherine Heymans, from the University of Edinburgh's School of Physics and Astronomy, added: "By analyzing light from the distant Universe, we can learn about what it has traveled through on its journey to reach us. We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe."

Both Heymans and Van Waerbeke lead the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) team.

Read more at Discovery News

Not All Meteors the Same

Scientists have unravelled the mystery of why some meteors flash across the night sky burning up as shooting stars, while others survive raining gently down to the ground.

The discovery by David Nesvorny from the Southwest Research Institute in Boulder, Colo. and colleagues was made during a study of an astronomcical feature known as the Zodiacal Cloud.

The Zodiacal Cloud is a diffuse glow of scattered sunlight in the night sky. Models predict that micro-meteoroids enter the Earth's atmosphere at relatively low speeds, gently raining down onto the ground. But meteor radars consistently see the sky filled with rapidly speeding meteors flying too fast to survive.

Nesvorny and colleagues found the inconsistency was caused by some meteor radars not being able to see the slower, smaller meteors, instead only detecting the bigger faster ones which people see as shooting stars.

Reporting in the Astrophysical Journal and on the pre-press website ArXiv.org, Nesvorny and colleagues found that 90 percent of the dust in the Zodiacal Cloud comes from Jupiter family comets such as 2P/Encke, whose orbits are influenced by the giant gas planet.

These appear to have compositions which cause them to slow down rapidly once they enter the Earth's atmosphere, allowing them to survive and reach the ground often as micrometeorites no bigger than grains of dust.

The remaining 10 percent of material in the Zodiacal Cloud comes from Oort Cloud comets, Halley-type comets and asteroid collisions.

They are usually associated with cometary debris trails seen as meteor showers, and because they're traveling faster when they hit the Earth's atmosphere, they're more likely to burn up as shooting stars.

Meteoroids and their tiny counter parts micro-meteoroids often fly through space at speeds of 40,000 kilometers per hour (25,000 miles per hour). Meteors that enter the Earth's atmosphere and reach the ground are called meteorites.

Astronomer Dr Fred Watson from the Australian Astronomical Observatory says the study provides a new insight into the amount of dust and debris falling into the Earth's atmosphere every year.

"Their figure of 15,000 tons a year is considerably more than previously thought," said Watson. "When you think about it, that's an extraordinary amount of stuff falling down to the Earth's surface. It's a train's worth of stuff."

Read more at Discovery News

Jan 8, 2012

Whiff of 'Love Hormone' Helps Monkeys Show a Little Kindness

Oxytocin, the "love hormone" that builds mother-baby bonds and may help us feel more connected toward one another, can also make surly monkeys treat each other a little more kindly.

Administering the hormone nasally through a kid-sized nebulizer, like a gas mask, a Duke University research team has shown that it can make rhesus macaques pay more attention to each other and make choices that give another monkey a squirt of fruit juice, even when they don't get one themselves.

Two macaques were seated next to each other and trained to select symbols from a screen that represented giving a rewarding squirt of juice to one's self, giving juice to the neighbor, or not handing out any juice at all. In repeated trials, they were faced with a choice between just two of these options at a time: reward to self vs. no reward; reward to self vs. reward to other; and reward to other vs. no reward.

"The inhaled oxytocin enhanced 'prosocial' choices by the monkeys, perhaps by making them pay more attention to the other individual," said neuroscientist Michael Platt, who headed the study and is director of the Duke Institute for Brain Sciences. "If that's true, it's really cool, because it suggests that oxytocin breaks down normal social barriers."

Earlier work by Platt's group had shown that macaques would rather give a reward to another monkey when the alternative is no reward for anyone, a concept they call "vicarious reinforcement." Their data in the latest study show an apparent improvement in vicarious reinforcement about a half-hour after exposure to oxytocin. Interestingly, for the first half-hour, the monkey was more likely to reward itself.

The researchers also tracked the monkeys' eye movements. Typically after making a prosocial choice, they will shift their gaze to the other monkey. Under the influence of oxytocin, the gaze lingered a bit more when they made other vs. neither choices.

The hormone is currently being evaluated as a therapy for autism, schizophrenia and other disorders that are marked by an apparent lack of interest or caring about others, Platt said. It seems to give patients increased trust and better social skills, but not much is known about how that process works, or whether the effects would be consistent over the long term.

This study may help establish monkeys as a good behavioral and pharmacological model for understanding oxytocin therapy, Platt said.

The nebulizer mask used in these tests is also more pleasant than the sprays now being used on humans, he added. "We were able to make the inhalation very tolerable by using the pediatric nebulizer," Platt said. "This may be much better for treating young children with autism or related disorders than the typical nasal spray, which can be uncomfortable. It may deliver the hormone more effectively, too."

Read more at Science Daily

Stephen Hawking, Defying Science, Turns 70

When Stephen Hawking was diagnosed with motor neurone disease aged just 21, he was given only a few years to live. But the British scientist marks his 70th birthday on Sunday, as questioning as ever.

Despite spending most of his life crippled in a wheelchair and able to speak only through a computer, the theoretical physicist's quest for the secrets of the universe has made him arguably the most famous scientist in the world.

"I'm sure my disability has a bearing on why I'm well known," Hawking once said. "People are fascinated by the contrast between my very limited physical powers, and the vast nature of the universe I deal with."

Much of his work has centered on bringing together relativity (the nature of space and time) and quantum theory (how the smallest particles in the universe behave) to explain the creation of the universe and how it is governed.

In 1974, aged just 32, he became one of the youngest fellows of Britain's prestigious Royal Society. Five years later he became Lucasian Professor of Mathematics at Cambridge University, a post once held by Isaac Newton.

His fame moved beyond academia in 1988 with the publication of his book "A Brief History of Time," which explained the nature of the universe to non-scientists, and sold millions of copies worldwide.

Hawking's stardom was later cemented in cameos in "Star Trek" and "The Simpsons," where he tells the rotund Homer Simpson that he likes his theory of a "doughnut-shaped universe," and may have to steal it.

Martin Rees, Britain's Astronomer Royal and a former president of the Royal Society, first met Hawking when they were both research students "and it was thought he might not live long enough to finish his PhD degree."

Rees said his survival made him a "medical marvel", but stressed that it was his work that would prove his lasting legacy.

"His fame should not overshadow his scientific contributions because even though most scientists are not as famous as he is, he has undoubtedly done more than anyone else since Einstein to improve our knowledge of gravity," he said.

Hawking was just 21 when he was diagnosed with amyotrophic lateral sclerosis (ALS), a former of motor neurone disease that attacks the nerves controlling voluntary movement.

Brian Dickie, research director of the MND Association, says most sufferers live for less than five years -- "the fact that Stephen Hawking has lived with the disease for close to 50 years makes him exceptional."

Hawking admitted he felt "somewhat of a tragic character" after diagnosis, but he soon returned to work, securing a fellowship at Cambridge, and married Jane Wilde, with whom he had three children.

Professor Kip Thorne, the acclaimed US theoretical physicist who will speak at a special symposium at Cambridge for Hawking's birthday on Sunday, said his illness had in fact been instrumental to his work.

"When Stephen lost the use of his hands and could no longer manipulate equations on paper, he compensated by training himself to manipulate complex shapes and topologies in his mind at great speed," he said.

"That ability has enabled him to see the solutions to deep physics problems that nobody else could solve, and that he probably would not have been able to solve, himself, without his newfound skill."

In addition to Sunday's symposium on 'the state of the universe', Hawking's birthday will be marked by a new exhibition celebrating his achievements which opens at London's Science Museum on January 20.

Hawking retired as Lucasian Professor of Maths when he reached 67, but his fascination with the world remains.

He is watching the progress of the Large Hadron Collider closely, having bet $100 in 2009 that it will not find an elusive particle seen as the holy grail of cosmic science.

Read more at Discovery News