Gigantic ring system around J1407b much larger, heavier than Saturn's

Artist's conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b is shown. The rings are shown eclipsing the young sun-like star J1407, as they would have appeared in early 2007. The best fit model is consistent with a system of at least 30 rings, and there are gaps where satellites ("exomoons") may have already formed.

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system -- the first of its kind to be found outside our solar system -- was discovered in 2012 by a team led by Rochester's Eric Mamajek.

A new analysis of the data, led by Leiden's Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter. Furthermore, they found gaps in the rings, which indicate that satellites ("exomoons") may have formed. The result has been accepted for publication in the Astrophysical Journal.

"The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings," says Kenworthy. "The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn's rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon."

"This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn's rings are today," said co-author Mamajek, professor of physics and astronomy at the University of Rochester. "You could think of it as kind of a super Saturn."

The astronomers analyzed data from the SuperWASP project -- a survey that is designed to detect gas giants that move in front of their parent star. In 2012, Mamajek and colleagues at the University of Rochester reported the discovery of the young star J1407 and the unusual eclipses, and proposed that they were caused by a moon-forming disk around a young giant planet or brown dwarf.

In a third, more recent study also led by Kenworthy, adaptive optics and Doppler spectroscopy were used to estimate the mass of the ringed object. Their conclusions based on these and previous papers on the intriguing system J1407 is that the companion is likely to be a giant planet -- not yet seen -- with a gigantic ring system responsible for the repeated dimming of J1407's light.

The light curve tells astronomers that the diameter of the ring system is nearly 120 million kilometers, more than two hundred times as large as the rings of Saturn. The ring system likely contains roughly an Earth's worth of mass in light-obscuring dust particles.

Mamajek puts into context how much material is contained in these disks and rings. "If you were to grind up the four large Galilean moons of Jupiter into dust and ice and spread out the material over their orbits in a ring around Jupiter, the ring would be so opaque to light that a distant observer that saw the ring pass in front of the sun would see a very deep, multi-day eclipse," Mamajek says. "In the case of J1407, we see the rings blocking as much as 95 percent of the light of this young Sun-like star for days, so there is a lot of material there that could then form satellites."

In the data the astronomers found at least one clean gap in the ring structure, which is more clearly defined in the new model. "One obvious explanation is that a satellite formed and carved out this gap," says Kenworthy. "The mass of the satellite could be between that of Earth and Mars. The satellite would have an orbital period of approximately two years around J1407b."

Astronomers expect that the rings will become thinner in the next several million years and eventually disappear as satellites form from the material in the disks.

"The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites," Mamajek explains. "However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object."

Astronomers estimate that the ringed companion J1407b has an orbital period roughly a decade in length. The mass of J1407b has been difficult to constrain, but it is most likely in the range of about 10 to 40 Jupiter masses.

The researchers encourage amateur astronomers to help monitor J1407, which would help detect the next eclipse of the rings, and constrain the period and mass of the ringed companion. Observations of J1407 can be reported to the American Association of Variable Star Observers (AAVSO). In the meantime the astronomers are searching other photometric surveys looking for eclipses by yet undiscovered ring systems.

Kenworthy adds that finding eclipses from more objects like J1407's companion "is the only feasible way we have of observing the early conditions of satellite formation for the near future. J1407's eclipses will allow us to study the physical and chemical properties of satellite-spawning circumplanetary disks."

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Girls lead boys in academic achievement globally

An international study shows that girls outperform boys in educational achievement in 70 percent of the countries they studied -- regardless of the level of gender, political, economic or social equality.

Considerable attention has been paid to how boys' educational achievements in science and math compare to girls' accomplishments in those areas, often leading to the assumption that boys outperform girls in these areas. Now, using international data, researchers at the University of Missouri and the University of Glasgow in Glasgow, Scotland, have determined that girls outperform boys in educational achievement in 70 percent of the countries they studied -- regardless of the level of gender, political, economic or social equality.

"We studied the educational achievement levels of 1.5 million 15-year-olds from around the world using data collected between 2000 and 2010," said David Geary, Curators Professor of Psychological Sciences in the College of Arts and Science at MU. "Even in countries where women's liberties are severely restricted, we found that girls are outperforming boys in reading, mathematics, and science literacy by age 15, regardless of political, economic, social or gender equality issues and policies found in those countries."

According to the data, boys fall behind girls in overall achievement across reading, mathematics, and science in 70 percent of the countries studied. Boys outperform girls in only three countries or regions: Colombia, Costa Rica and the Indian state, Himachal Pradesh. Boys and girls had similar educational achievements in the United States and United Kingdom.

In countries known for relatively low gender equality ratings, such as Qatar, Jordan and the United Arab Emirates, the educational achievement gap is relatively large and favors girls.

The one exception worldwide is among students in economically developed nations where high achieving boys outperform high achieving girls, researchers said.

"With the exception of high-achievers, boys have poorer educational outcomes than girls around the world, independent of social equality indicators," said Gijsbert Stoet, reader in psychology at the University of Glasgow. "Results show that a commitment to gender equality on its own is not enough to close the achievement gaps in global education; the gap is not increasing. Although it is vital that we promote gender equality in schools, we also need to make sure that we're doing more to understand why these gaps, especially among boys, persist and what other policies we can develop to close them."

The study also has important implications for educational policy, the researchers said.

"The data will influence how policymakers think about the options available," said Geary. "For example, to increase levels of equal opportunities in education. We believe that policymakers and educators should not expect that broad progress in social equality will necessarily result in educational equality. In fact, we found that with the exception of high achievers, boys have poorer educational outcomes than girls around the world, independent of social equality indicators. Therefore, in order to effectively close the gaps in achievement, education policymakers should consider factors other than political, economic and social equality, and especially as related to boys' overall achievement and high-achieving girls' interest in mathematics and science."

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3-D view of Greenland Ice Sheet opens window on ice history

This is a cross-section of the age of the Greenland Ice Sheet. Layers determined to be from the Holocene period, formed during the past 11,700 years, are shown in green. Layers accumulated during the last ice age, from 11,700 to 115,000 years ago, are shown in blue. Layers from the Eemian period, more than 115,000 years old, are shown in red. Regions of unknown age are gray.

Scientists using ice-penetrating radar data collected by NASA's Operation IceBridge and earlier airborne campaigns have built the first comprehensive map of layers deep inside the Greenland Ice Sheet, opening a window on past climate conditions and the ice sheet's potentially perilous future.

This new map allows scientists to determine the age of large swaths of the second largest mass of ice on Earth, an area containing enough water to raise ocean levels by about 20 feet.

"This new, huge data volume records how the ice sheet evolved and how it's flowing today," said Joe MacGregor, the study's lead author, a glaciologist at The University of Texas at Austin Institute for Geophysics (UTIG), a unit of the Jackson School of Geosciences.

Greenland's ice sheet has been losing mass during the past two decades, a phenomenon accelerated by warming temperatures. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.

Ice cores offer one way of studying the distant past. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities such as dust and volcanic ash compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.

Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.

New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods.

Another major factor in this study was the scope of Operation IceBridge's measurements across Greenland, which included flights that covered distances of tens of thousands of kilometers across the ice sheet.

"IceBridge surveyed previously unexplored parts of the Greenland Ice Sheet and did it using state-of-the-art CReSIS radars," said study co-author Mark Fahnestock, an IceBridge science team member and glaciologist from the Geophysical Institute at the University of Alaska Fairbanks (UAF-GI).

CReSIS is the Center for Remote Sensing of Ice Sheets, a National Science Foundation science and technology center headquartered at the University of Kansas in Lawrence, Kansas.

IceBridge's flight lines often intersect ice core sites where other scientists have analyzed the ice's chemical composition to map and date layers in the ice. These core data provide a reference for radar measurements and provide a way to calculate how much ice from a given climate period exists across the ice sheet, something known as an age volume. Scientists are interested in knowing more about ice from the Eemian period, a time from 115,000 to 130,000 years ago that was about as warm as today. This new age volume provides the first data-driven estimate of where Eemian ice may remain.

Comparing this age volume to simple computer models helped the study's team better understand the ice sheet's history. Differences in the mapped and modeled age volumes point to past changes in ice flow or processes such as melting at the ice sheet's base. This information will be helpful for evaluating the more sophisticated ice sheet models that are crucial for projecting Greenland's future contribution to sea-level rise.

"Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right. Now, they'll also be able to work on getting its history right, which is important because ice sheets have very long memories," said MacGregor.

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Family voices, stories speed coma recovery

When patients in the study heard the voice of a family member calling their names out loud and reciting stories while they were in an MRI, their brains showed increased neural activity. "We saw changes in the blood oxygen level in their brain regions associated with retrieving long-term memory and understanding language," Pape said. "That means they were using those regions of their brains."

"Can he hear me?" family members are desperate to know when a loved one with a traumatic brain injury is in a coma.

A new Northwestern Medicine and Hines VA Hospital study shows the voices of loved ones telling the patient familiar stories stored in his long-term memory can help awaken the unconscious brain and speed recovery from the coma.

Coma patients who heard familiar stories repeated by family members four times a day for six weeks, via recordings played over headphones, recovered consciousness significantly faster and had an improved recovery compared to patients who did not hear the stories, reports the study.

The paper was published in the journal Neurorehabilitation and Neural Repair January 22.

"We believe hearing those stories in parents' and siblings' voices exercises the circuits in the brain responsible for long-term memories," said lead author Theresa Pape. "That stimulation helped trigger the first glimmer of awareness."

As a result, the coma patients can wake more easily, become more aware of their environment and start responding to conversations and directions.

"It's like coming out of anesthesia," Pape said. "It's the first step in recovering full consciousness."

Pape is a neuroscientist in physical medicine and rehabilitation at Northwestern University Feinberg School of Medicine and a neuroscientist at Hines VA.

"After the study treatment, I could tap them on the shoulder, and they would look at me," Pape said. "Before the treatment they wouldn't do that."

Being more aware of their environment means the patients can actively participate in physical, speech and occupational therapy, all essential for their rehabilitation.

A coma is an unconscious condition in which the patient can't open his eyes. Patients usually progress from a coma to either a minimally conscious or vegetative state, and these states can last a few weeks, months or years. Every five seconds, someone in the U.S. has a traumatic brain injury. Troops deployed to wars zones are at an even greater risk for having a severe enough brain injury to cause a coma.

"It's an incredibly common and devastating injury," Pape said.

The familiar voices treatment also benefits families.

"Families feel helpless and out of control when a loved one is in a coma," Pape said. "It's a terrible feeling for them. This gives them a sense of control over the patient's recovery and the chance to be part of the treatment."

Such was the case for Corinth Catanus, whose husband, Godfrey, a former California youth minister, was a participant in the study after being in a coma for three months. "The stories I told him helped Godfrey recover from his coma, and they helped me feel I could do something for him," she said. "That gave me hope." (More on Godfrey and Corinth's story below.)

The Brain Lit Up in Response to Family Voices

When patients like Godfrey Catanus in the study heard the voice of a family member calling their names out loud and reciting stories while they were in an MRI, their brains showed increased neural activity. This was indicated by bright yellow and red blobs of light in regions involved with understanding language and long-term memory.

"We saw changes in the blood oxygen level in their brain regions associated with retrieving long-term memory and understanding language," Pape said. "That means they were using those regions of their brains."

How the Study Worked

The randomized, placebo-controlled study, Familiar Auditory Sensory Training (FAST), enrolled 15 patients with traumatic closed head injuries who were in a vegetative or minimally conscious state. They were an average age of 35 (12 men and three women) with injuries caused by motorcycle or car accidents, bomb traumas or assaults. The FAST treatment began an average of 70 days after the injury.

Pape and colleagues first did baseline testing to see how responsive patients were to sensory information such as bells or whistles, if they followed directions to open their eyes and if they were alert enough to visually track someone walking across the room. Their responses provided a benchmark to see if they changed or improved after six weeks of treatment. (A person in a minimally conscious state can occasionally follow directions.)

Scientists also had the patients listen to familiar and non-familiar voices tell different stories to get a baseline MRI of how the blood oxygen levels in their brains changed while listening.

Collecting Family Stories to Tell

The next step was having families work with therapists to identify and construct the important stories about events that the patient and family participated in together.

"It could be a family wedding or a special road trip together such as going to visit colleges," Pape said. "It had to be something they'd remember, and we needed to bring the stories to life with sensations, temperature and movement. Families would describe the air rushing past the patient as he rode in the Corvette with the top down or the cold air on his face as he skied down a mountain slope."

Families brought in an armful of photo albums to come up with topics for the stories. Then parents and siblings recorded at least eight stories, which they practiced reciting naturally and using the patient's nickname.

After six weeks of listening to the recorded stories, Pape repeated the earlier baseline tests in an MRI. In one, patients listened to familiar and unfamiliar voices telling the same story they heard at baseline (a short joke about a man buying ice-cream and getting a pickle with it.)

The MRI image showed a change in the oxygen level, indicating greater responsiveness to the unfamiliar voice telling a story. The oxygen level did not change for the familiar voice, which remained the same as baseline.

"This indicates the patient's ability to process and understand what they're hearing is much better," Pape said. "At baseline they didn't pay attention to that non-familiar voice. But now they are processing what that person is saying.''

In another test, patients listened to a small bell ringing as before. But this time, patients' brains responded less to the bell, indicating they were better able to discriminate what's important to listen to.

"Mom's voice telling them familiar stories over and over helped their brains pay attention to important information rather than the bell," Pape said. "They were able to filter out what was relevant and what wasn't."

The biggest gains in recovery came in the first two weeks of the treatment, with small incremental gains over the next four weeks.

Pape is currently analyzing her data to determine if the FAST intervention strengthened the brain's wiring, the elongated fibers called axons that transmit signals between neurons.

Recording and playing the stories is something all families can do when a loved one is in a coma. It is logical that people in a coma as a result of a stroke would also respond favorably to the treatment, Pape said.

"This gives families hope and something they can control," Pape said. She recommends families work with a therapist to help them construct the stories. The recorded stories can augment the other therapies a patient is undergoing.

Why Pape Launched the Study

Pape was inspired to launch the study based on families' feedback while she worked as a speech therapist for coma patients with traumatic brain injuries. Families often told her the patient responded better to them than to a stranger. Pape began to observe the patients with families and saw they were right.

Pape speculated that if therapists could stimulate and exercise people's brains when they are unconscious, it would help them recover. She developed the protocol to see if it worked. The study was funded by V.A.'s Rehabilitation, Research and Development Service.

Patient Godfrey Catanus Emerges from Coma

Corinth Catanus's voice, recorded on a CD, playfully reminded her husband, Godfrey, of the morning she craved chicken nuggets during her second pregnancy.

"Remember the morning I had a craving for chicken nuggets, and no fast food restaurant sold it that early in the morning?" she asked. He drove to several fast-food locations across town before work to find them, she recalled, only to discover they were the wrong kind when he arrived home. That night he renewed his quest until he snagged the exact ones she coveted.

Family stories like these -- recorded by Corinth and Godfrey's brothers -- were played through headphones for Godfrey four times a day while he lay in a three-month coma. He was part of a Northwestern Medicine and Hines V.A. clinical trial that studied whether repeated stimulation with familiar voices could help repair a coma victim's injured brain networks and spur his recovery.

Those recordings helped awaken Godfrey from his vegetative state and pull him back to consciousness, based on the new study findings.

Godfrey recalls hearing Corinth's voice and his brother's voice on the recordings during that time.

"It was comforting to think that they were 'there' with me," Godfrey wrote in an email. "It helped me by giving my brain something to connect with."

In 2010, Godfrey, then a 32-year-old youth minister in Irvine, California, suffered a brain injury and went into a coma. Corinth, a neonatal intensive care nurse, was pregnant with their second child at the time.

The couple grew up in the Chicago suburbs, and Corinth wanted Godfrey to be treated at the Rehabilitation Institute of Chicago. Their church raised funds to hire an air ambulance to transport the comatose Godfrey to the Chicago hospital. While there, the family learned about the familiar voices study and wanted to participate.

After several weeks of listening to the tapes, Godfrey, who was severely disabled by his injury and unable to speak easily, slowly began to respond by gesture to questions asked by his therapist. But his responses were inconsistent. Then Corinth asked him something she knew could get a rise out of the devoted Chicago basketball fan.

"Will you ever be a Lakers' fan?" she asked mischievously. Godfrey stared hard at the "no" card. "Will you always be a Chicago Bulls' fan?" His gaze shifted unequivocally to "yes."

"That was the turning point," Corinth said. "I realized he was becoming more aware and more conscious," Corinth said.

Godfrey progressed and began typing out messages on an iPad. One of the first things he wrote, "I wish I could go to Disneyland." It was a favorite trip for the family.

Four years later, Godfrey now writes weekly devotionals that appear in his church's bulletin and website. And he is involved in his family's life. He reminds Corinth, via his iPad, about the family's daily schedule like doctor's appointments for their daughters or his bus pick up to go to physical therapy. His daughters like to hang out with him on his wheelchair.

"The voices treatment made a huge difference in his recovery," Corinth said. "I know it helped bring him back to us."

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Why all-nighters don't work: How sleep, memory go hand-in-hand

Understanding how sleep and memory are connected in a simple system, like Drosophila, can help scientists unravel the secrets of the human brain.

Want to ace that test tomorrow? Here's a tip: Put down the coffee and hit the sack.

Scientists have long known that sleep, memory and learning are deeply connected. Most animals, from flies to humans, have trouble remembering when sleep deprived, and studies have shown that sleep is critical in converting short-term into long-term memory, a process known as memory consolidation.

But just how that process works has remained a mystery.

The question is, does the mechanism that promotes sleep also consolidate memory, or do two distinct processes work together? In other words, is memory consolidated during sleep because the brain is quiet, allowing memory neurons to go to work, or are memory neurons actually putting us to sleep?

In a recent paper in the journal eLife, graduate students Paula Haynes and Bethany Christmann in the Griffith Lab make a case for the latter.

Haynes and Christmann focused their research on dorsal paired medial (DPM) neurons, well-known memory consolidators in Drosophila. They observed, for the first time, that when DPM neurons are activated, the flies slept more; when deactivated, the flies kept buzzing.

These memory consolidators inhibit wakefulness as they start converting short-term to long-term memory. All this takes place in a section of the Drosophila brain called the mushroom body, similar to the hippocampus, where our memories are stored. As it turns out, the parts of the mushroom body responsible for memory and learning also help keep the Drosophila awake.

"It's almost as if that section of the mushroom body were saying 'hey, stay awake and learn this,'" says Christmann. "Then, after a while, the DPM neurons start signaling to suppress that section, as if to say 'you're going to need sleep if you want to remember this later.'"

Understanding how sleep and memory are connected in a simple system, like Drosophila, can help scientists unravel the secrets of the human brain.

"Knowing that sleep and memory overlap in the fly brain can allow researchers to narrow their search in humans," Christmann says. "Eventually, it could help us figure out how sleep or memory is affected when things go wrong, as in the case of insomnia or memory disorders."

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Climate affects development of human speech

Dry land (stock image). Many languages of the world use tone or pitch to give meaning to their words. Linguist Caleb Everett and his collaborators have uncovered that languages with complex tones -- those that use three or more tones for sound contrast -- are much more likely to occur in humid regions of the world, while languages with simple tone occur more frequently in desiccated regions, whether frigid areas or dry deserts.

An interesting question, one that linguists have long debated, is whether climate and geography affect language. The challenge has been to untangle the factors that cause sounds to change.

To find a relationship between the climate and the evolution of language, one needs to discover an association between the environment and vocal sounds that is consistent throughout the world and present in different languages. And that is precisely what a group of researchers has done.

Many languages of the world use tone or pitch to give meaning to their words. University of Miami (UM) linguist Caleb Everett and his collaborators have uncovered that languages with complex tones --those that use three or more tones for sound contrast -- are much more likely to occur in humid regions of the world, while languages with simple tone occur more frequently in desiccated regions, whether frigid areas or dry deserts.

"In my estimation, it changes a bit our understanding of how languages evolve," said Everett, associate professor in the Department of Anthropology at the UM College of Arts and Sciences, and lead investigator of this project. "It does not imply that languages are completely determined by climate, but that climate can, over the long haul, be one of the factors that helps shape languages."

"More broadly, this suggests another non-conscious way in which humans have adapted to their very different and harsh environments," Everett said. "Also, there may be some health benefits to certain sound patterns in certain climates, but more research is needed to establish that in a satisfactory way."

One explanation, supported by extensive experimental data discussed in the study, is that inhaling dry air causes laryngeal dehydration and decreases vocal fold elasticity. It's probably more difficult to achieve complex tones in arid climates--particularly very cold ones--when contrasted to warmer and more humid climates. The result is that deviations of sounds, including increased jitter and shimmer, are associated with very cold or desiccated climates, the study says.

The findings are published in the Proceedings of the National Academy of Sciences. They provide extensive evidence that sound systems of human languages are adaptive and can be influenced by climate. The findings are supported by data relating to over half of the world's languages and to previous extensive experimental research on the properties of the human larynx that affect tonality.

The team examined more than 3,700 languages and found 629 languages with complex tones. Most were found in tropical regions, throughout Africa and Southeast Asia, but also in some humid regions of North America, Amazonia and New Guinea.

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Scientists slow down the speed of light travelling in free space

Scientists have long known that the speed of light can be slowed slightly as it travels through materials such as water or glass.

However, it has generally been thought impossible for particles of light, known as photons, to be slowed as they travel through free space, unimpeded by interactions with any materials.

In a new paper published in Science Express today (Friday 23 January), researchers from the University of Glasgow and Heriot-Watt University describe how they have managed to slow photons in free space for the first time. They have demonstrated that applying a mask to an optical beam to give photons a spatial structure can reduce their speed.

The team compare a beam of light, containing many photons, to a team of cyclists who share the work by taking it in turns to cycle at the front. Although the group travels along the road as a unit, the speed of individual cyclists can vary as they swap position.

The group formation can make it difficult to define a single velocity for all cyclists, and the same applies to light. A single pulse of light contains many photons, and scientists know that light pulses are characterised by a number of different velocities.

The team's experiment was configured like a time trial race, with two photons released simultaneously across identical distances towards a defined finish line. The researchers found that one photon reached the finish line as predicted, but the structured photon which had been reshaped by the mask arrived later, meaning it was travelling more slowly in free space. Over a distance of one metre, the team measured a slowing of up to 20 wavelengths, many times greater than the measurement precision.

The work demonstrates that, after passing the light beam through a mask, photons move more slowly through space. Crucially, this is very different to the slowing effect of passing light through a medium such as glass or water, where the light is only slowed during the time it is passing through the material -- it returns to the speed of light after it comes out the other side. The effect of passing the light through the mask is to limit the top speed at which the photons can travel.

The work was carried out by a team from the University of Glasgow's Optics Group, led by Professor Miles Padgett, working with theoretical physicists led by Stephen Barnett, and in partnership with Daniele Faccio from Heriot-Watt University.

Daniel Giovannini, one of the lead authors of the paper, said: "The delay we've introduced to the structured beam is small, measured at several micrometres over a propagation distance of one metre, but it is significant. We've measured similar effects in two different types of beams known as Bessel beams and Gaussian beams."

Co-lead author Jacquiline Romero said: "We've achieved this slowing effect with some subtle but widely-known optical principles. This finding shows unambiguously that the propagation of light can be slowed below the commonly accepted figure of 299,792,458 metres per second, even when travelling in air or vacuum.

"Although we measure the effect for a single photon, it applies to bright light beams too. The effect is biggest when the lenses used to create the beam are large and when the distance over which the light is focused is small, meaning the effect only applies at short range."

Professor Padgett added: "It might seem surprising that light can be made to travel more slowly like this, but the effect has a solid theoretical foundation and we're confident that our observations are correct.

"The results give us a new way to think about the properties of light and we're keen to continue exploring the potential of this discovery in future applications. We expect that the effect will be applicable to any wave theory, so a similar slowing could well be created in sound waves, for example."

The team's paper, titled 'Spatially Structured Photons that Travel in Free Space Slower than the Speed of Light', is published in Science Express, which provides electronic publication of selected papers in advance of print in the journal Science.

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Telomere extension turns back aging clock in cultured human cells, study finds

A new procedure can quickly and efficiently increase the length of human telomeres, the protective caps on the ends of chromosomes that are linked to aging and disease, according to scientists at the Stanford University School of Medicine.

Treated cells behave as if they are much younger than untreated cells, multiplying with abandon in the laboratory dish rather than stagnating or dying.

The procedure, which involves the use of a modified type of RNA, will improve the ability of researchers to generate large numbers of cells for study or drug development, the scientists say. Skin cells with telomeres lengthened by the procedure were able to divide up to 40 more times than untreated cells. The research may point to new ways to treat diseases caused by shortened telomeres.

Telomeres are the protective caps on the ends of the strands of DNA called chromosomes, which house our genomes. In young humans, telomeres are about 8,000-10,000 nucleotides long. They shorten with each cell division, however, and when they reach a critical length the cell stops dividing or dies. This internal "clock" makes it difficult to keep most cells growing in a laboratory for more than a few cell doublings.

'Turning back the internal clock'

"Now we have found a way to lengthen human telomeres by as much as 1,000 nucleotides, turning back the internal clock in these cells by the equivalent of many years of human life," said Helen Blau, PhD, professor of microbiology and immunology at Stanford and director of the university's Baxter Laboratory for Stem Cell Biology. "This greatly increases the number of cells available for studies such as drug testing or disease modeling."

A paper describing the research was published today in the FASEB Journal. Blau, who also holds the Donald E. and Delia B. Baxter Professorship, is the senior author. Postdoctoral scholar John Ramunas, PhD, of Stanford shares lead authorship with Eduard Yakubov, PhD, of the Houston Methodist Research Institute.

The researchers used modified messenger RNA to extend the telomeres. RNA carries instructions from genes in the DNA to the cell's protein-making factories. The RNA used in this experiment contained the coding sequence for TERT, the active component of a naturally occurring enzyme called telomerase. Telomerase is expressed by stem cells, including those that give rise to sperm and egg cells, to ensure that the telomeres of these cells stay in tip-top shape for the next generation. Most other types of cells, however, express very low levels of telomerase.

Transient effect an advantage

The newly developed technique has an important advantage over other potential methods: It's temporary. The modified RNA is designed to reduce the cell's immune response to the treatment and allow the TERT-encoding message to stick around a bit longer than an unmodified message would. But it dissipates and is gone within about 48 hours. After that time, the newly lengthened telomeres begin to progressively shorten again with each cell division.

The transient effect is somewhat like tapping the gas pedal in one of a fleet of cars coasting slowly to a stop. The car with the extra surge of energy will go farther than its peers, but it will still come to an eventual halt when its forward momentum is spent. On a biological level, this means the treated cells don't go on to divide indefinitely, which would make them too dangerous to use as a potential therapy in humans because of the risk of cancer.

The researchers found that as few as three applications of the modified RNA over a period of a few days could significantly increase the length of the telomeres in cultured human muscle and skin cells. A 1,000-nucleotide addition represents a more than 10 percent increase in the length of the telomeres. These cells divided many more times in the culture dish than did untreated cells: about 28 more times for the skin cells, and about three more times for the muscle cells.

"We were surprised and pleased that modified TERT mRNA worked, because TERT is highly regulated and must bind to another component of telomerase," said Ramunas. "Previous attempts to deliver mRNA-encoding TERT caused an immune response against telomerase, which could be deleterious. In contrast, our technique is nonimmunogenic. Existing transient methods of extending telomeres act slowly, whereas our method acts over just a few days to reverse telomere shortening that occurs over more than a decade of normal aging. This suggests that a treatment using our method could be brief and infrequent."

Potential uses for therapy

"This new approach paves the way toward preventing or treating diseases of aging," said Blau. "There are also highly debilitating genetic diseases associated with telomere shortening that could benefit from such a potential treatment."

Blau and her colleagues became interested in telomeres when previous work in her lab showed that the muscle stem cells of boys with Duchenne muscular dystrophy had telomeres that were much shorter than those of boys without the disease. This finding not only has implications for understanding how the cells function -- or don't function -- in making new muscle, but it also helps explain the limited ability to grow affected cells in the laboratory for study.

The researchers are now testing their new technique in other types of cells.

"This study is a first step toward the development of telomere extension to improve cell therapies and to possibly treat disorders of accelerated aging in humans," said John Cooke, MD, PhD. Cooke, a co-author of the study, formerly was a professor of cardiovascular medicine at Stanford. He is now chair of cardiovascular sciences at the Houston Methodist Research Institute.

"We're working to understand more about the differences among cell types, and how we can overcome those differences to allow this approach to be more universally useful," said Blau, who also is a member of the Stanford Institute for Stem Cell Biology and Regenerative Medicine.

"One day it may be possible to target muscle stem cells in a patient with Duchenne muscular dystrophy, for example, to extend their telomeres. There are also implications for treating conditions of aging, such as diabetes and heart disease. This has really opened the doors to consider all types of potential uses of this therapy."

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New research re-creates planet formation, super-Earths and giant planets in the laboratory

New laser-driven shock compression experiments on stishovite, a high-density form of silica, provide thermodynamic and electrical conductivity data at unprecedented conditions and reveal the unusual properties of rocks deep inside large exoplanets and giant planets.

New laser-driven compression experiments reproduce the conditions deep inside exotic super-Earths and giant planet cores, and the conditions during the violent birth of Earth-like planets, documenting the material properties that determined planet formation and evolution processes.

The experiments, reported in the Jan. 23 edition of Science, reveal the unusual properties of silica -- the key constituent of rock -- under the extreme pressures and temperatures relevant to planetary formation and interior evolution.

Using laser-driven shock compression and ultrafast diagnostics, Lawrence Livermore National Laboratory (LLNL) physicist Marius Millot and colleagues from Bayreuth University (Germany), LLNL and the University of California, Berkeley were able to measure the melting temperature of silica at 500 GPa (5 million atmospheres), a pressure comparable to the core-mantle boundary pressure for a super-Earth planet (5 Earth masses), Uranus and Neptune. It also is the regime of giant impacts that characterize the final stages of planet formation.

"Deep inside planets, extreme density, pressure and temperature strongly modify the properties of the constituent materials," Millot said. "How much heat solids can sustain before melting under pressure is key to determining a planet's internal structure and evolution, and now we can measure it directly in the laboratory."

In combination with prior melting measurements on other oxides and on iron, the new data indicate that mantle silicates and core metal have comparable melting temperatures above 300-500 GPa, suggesting that large rocky planets may commonly have long-lived oceans of magma -- molten rock -- at depth. Planetary magnetic fields can be formed in this liquid-rock layer.

"In addition, our research suggests that silica is likely solid inside Neptune, Uranus, Saturn and Jupiter cores, which sets new constraints on future improved models for the structure and evolution of these planets," Millot said.

Those advances were made possible by a breakthrough in high-pressure crystal growth techniques at Bayreuth University in Germany. There, Natalia Dubrovinskaia and colleagues managed to synthesize millimeter-sized transparent polycrystals and single crystals of stishovite, a high-density form of silica (SiO2) usually found only in minute amounts near meteor-impact craters.

Those crystals allowed Millot and colleagues to conduct the first laser-driven shock compression study of stishovite using ultrafast optical pyrometry and velocimetry at the Omega Laser Facility at the University of Rochester's Laboratory for Laser Energetics.

"Stishovite, being much denser than quartz or fused-silica, stays cooler under shock compression, and that allowed us to measure the melting temperature at a much higher pressure," Millot said. "Dynamic compression of planetary-relevant materials is a very exciting field right now. Deep inside planets hydrogen is a metallic fluid, helium rains, fluid silica is a metal and water may be superionic."

In fact, the recent discovery of more than 1,000 exoplanets orbiting other stars in our galaxy reveals the broad diversity of planetary systems, planet sizes and properties. It also sets a quest for habitable worlds hosting extraterrestrial life and shines new light on our own solar system. Using the ability to reproduce in the laboratory the extreme conditions deep inside giant planets, as well as during planet formation, Millot and colleagues plan to study the exotic behavior of the main planetary constituents using dynamic compression to contribute to a better understanding of the formation of the Earth and the origin of life.

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Early human ancestors used their hands like modern humans

Human and ape joining hands (stock image). Researchers examined the trabeculae of hand bones of humans and chimpanzees. They found clear differences between humans, who have a unique ability for forceful precision gripping between thumb and fingers, and chimpanzees, who cannot adopt human-like postures.

New research suggests pre-Homo human ancestral species, such as Australopithecus africanus, used human-like hand postures much earlier than was previously thought.

Anthropologists from the University of Kent, working with researchers from University College London, the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany) and the Vienna University of Technology (Austria), have produced the first research findings to support archaeological evidence for stone tool use among fossil australopiths 3-2 million years ago.

The distinctly human ability for forceful precision (e.g. when turning a key) and power "squeeze" gripping (e.g. when using a hammer) is linked to two key evolutionary transitions in hand use: a reduction in arboreal climbing and the manufacture and use of stone tools. However, it is unclear when these locomotory and manipulative transitions occurred.

Dr Matthew Skinner, Senior Lecturer in Biological Anthropology and Dr Tracy Kivell, Reader in Biological Anthropology, both of Kent's School of Anthropology and Conservation, used new techniques to reveal how fossil species were using their hands by examining the internal spongey structure of bone called trabeculae. Trabecular bone remodels quickly during life and can reflect the actual behaviour of individuals in their lifetime.

The researchers first examined the trabeculae of hand bones of humans and chimpanzees. They found clear differences between humans, who have a unique ability for forceful precision gripping between thumb and fingers, and chimpanzees, who cannot adopt human-like postures. This unique human pattern is present in known non-arboreal and stone tool-making fossil human species, such as Neanderthals.

The research, titled "Human-like hand use in Australopithecus africanus, shows that Australopithecus africanus," a 3-2 million-year-old species from South Africa traditionally considered not to have engaged in habitual tool manufacture, has a human-like trabecular bone pattern in the bones of the thumb and palm (the metacarpals) consistent with forceful opposition of the thumb and fingers typically adopted during tool use.

These results support previously published archaeological evidence for stone tool use in australopiths and provide skeletal evidence that our early ancestors used human-like hand postures much earlier and more frequently than previously considered.

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Rosetta Comet 'pouring' more water into space

Image acquired by the navigation camera on the European Space Agency's Rosetta spacecraft orbiting Comet 67P/Churyumov-Gerasimenko.

There has been a significant increase in the amount of water "pouring" out of comet 67P/Churyumov-Gerasimenko, the comet on which the Rosetta mission's Philae lander touched down in November 2014.

The 2.5-mile-wide (4-kilometer) comet was releasing the earthly equivalent of 40 ounces (1.2 liters) of water into space every second at the end of August 2014. The observations were made by NASA's Microwave Instrument for Rosetta Orbiter (MIRO), aboard the European Space Agency's Rosetta spacecraft. Science results from the MIRO team were released today as part of a special Rosetta-related issue of the journal Science.

"In observations over a period of three months [June through August, 2014], the amount of water in vapor form that the comet was dumping into space grew about tenfold," said Sam Gulkis, principal investigator of the MIRO instrument at NASA's Jet Propulsion Laboratory in Pasadena, California, and lead author of a paper appearing in the special issue. "To be up close and personal with a comet for an extended period of time has provided us with an unprecedented opportunity to see how comets transform from cold, icy bodies to active objects spewing out gas and dust as they get closer to the sun."

The MIRO instrument is a small and lightweight spectrometer that can map the abundance, temperature and velocity of cometary water vapor and other molecules that the nucleus releases. It can also measure the temperature up to about one inch (two centimeters) below the surface of the comet's nucleus. One reason the subsurface temperature is important is that the observed gases likely come from sublimating ices beneath the surface. By combining information on both the gas and the subsurface, MIRO will be able to study this process in detail.

Also in the paper released today, the MIRO team reports that 67P spews out more gas from certain locations and at certain times during its "day." The nucleus of 67P consists of two lobes of different sizes (often referred to as the "body" and "head" because of its duck-like shape), connected by a neck region. A substantial portion of the measured outgassing from June through September 2014 occurred from the neck region during the afternoon.

"That situation may be changing now that the comet is getting warmer," said Gulkis. "MIRO observations would need to be carefully analyzed to determine which factors in addition to the sun's warmth are responsible for the cometary outgassing."

Observations are continuing to search for variability in the production rate and changes in the parts of the nucleus that release gas as the comet's distance from the sun changes. This information will help scientists understand how comets evolve as they orbit and move toward and then away from the sun. The gas production rate is also important to the Rosetta navigation team controlling the spacecraft, as this flowing gas can alter the trajectory of the spacecraft.

In another 67P paper released today, it was revealed that the comet's atmosphere, or coma, is much less homogenous than expected and that comet outgassing varies significantly over time.

"If we would have just seen a steady increase of gases as we closed in on the comet, there would be no question about the heterogeneity of the nucleus," said Myrtha Hässig, a NASA-sponsored scientist from the Southwest Research Institute in San Antonio. "Instead we saw spikes in water readings, and a few hours later, a spike in carbon dioxide readings. This variation could be a temperature effect or a seasonal effect, or it could point to the possibility of comet migrations in the early solar system."

The measurements on the coma were made by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis Double Focusing Mass Spectrometer (ROSINA DFMS) instrument. Measuring the in situ coma composition at the position of the spacecraft, ROSINA data indicate that the water vapor signal is strongest overall. However, there are periods when the carbon monoxide and carbon dioxide abundances rival that of water.

"Taken together, the MIRO outgassing results and results about heterogeneous fountains from ROSINA suggest fascinating new details to be learned about how comets work,"said Claudia Alexander, NASA project scientist for the U.S. Rosetta team, from JPL. "These results are helping us move the field forward on how comets operate on a fundamental level."

Rosetta is currently about 107 million miles (171 million kilometers) from Earth and about 92 million miles (148 million kilometers) from the sun. Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, via both remote and in situ observations, the Rosetta mission should become a key to unlocking the history and evolution of our solar system, as well as answering questions regarding the origin of Earth's water and perhaps even life. Rosetta is the first mission in history to rendezvous with a comet, escort it as it orbits the sun, and deploy a lander to its surface.

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Exploring the use of alcohol-interactive prescription medication among US drinkers

Approximately 71 percent of American adults drink alcohol. While alcohol interacts negatively with a number of commonly prescribed medications, little is known on a population level about the use of alcohol-interactive (AI) prescription medication among US drinkers. A new study has found that almost 42 percent of drinkers in the US population have used one or more alcohol-interactive prescription medications.

Results will be published in the February 2015 online-only issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"To our knowledge there have been only four previous US population-based studies," said Rosalind A. Breslow, an epidemiologist in the division of epidemiology and prevention research at the National Institute on Alcohol Abuse and Alcoholism as well as corresponding author for the study. "Three, conducted only among elderly people, concluded that substantial numbers of seniors were both drinking and taking alcohol-interactive medications and called for increased awareness about possible harmful consequences. One, conducted among adults of all ages, had a similar conclusion based on assessment of a limited number of prescription medications. Ours is a national-level study that estimates the proportion of adult drinkers who use a wide range of prescription medications that can interact with alcohol to cause numerous harms ranging from nausea, headaches, and loss of coordination to internal bleeding, heart problems, and difficulties in breathing."

Breslow added that her group expected to find greater prevalence among older drinkers. "People develop more chronic diseases as they age," she said, "so older people are more likely to be taking medications, many of which can interact harmfully with alcohol. They also may be taking multiple medications to treat multiple diseases. In addition, older people are at particularly high risk for harmful alcohol-medication interactions. There is some evidence that, as we age, our ability to metabolize alcohol decreases so alcohol might remain in our systems longer to interact with medications. Furthermore, the metabolism of several medications that interact with alcohol slows as we get older, creating a larger window for potential alcohol/medication interactions. For instance, diazepam -- known as Valium -- hangs around in the body about three times longer in a 60-year-old than a 20-year-old, thereby creating a much longer window for potential interactions with alcohol."

Breslow and her co-authors examined data from the 1999-2010 National Health and Nutrition Examination Survey, in which 26,657 adults (13,557 men, 13,100 women) aged ?20 years had provided data on past-year alcohol consumption and past-month prescription medication use. Analyses were adjusted for age, race/ethnicity, education, marital status, and smoking, and were also weighted in order to be nationally representative.

"Almost 42 percent of drinkers in the US population used one or more AI prescription medications," said Breslow. "Among seniors, aged 65 and older, the proportion was even higher, almost 78 percent. Regardless of age, the main therapeutic classes of AI medications used in the population were cardiovascular agents such as blood pressure medications, central nervous system agents such as sleeping pills, pain medications, and muscle relaxers, metabolic agents such as medications for diabetes and cholesterol, and psychotherapeutic agents such as antidepressants and antipsychotics."

Breslow noted that her group had expected a high prevalence rate, however, she emphasized that the data referred to potential, not actual, prevalence. "The data don't tell us exactly how many people in that 41.5 percent actually drink and take their medications within a similar time frame or how often they do so," she said. "However, if someone drinks regularly and takes medications regularly, the likelihood of taking them within a similar time frame is pretty high."

According to co-author Aaron White, a neuroscientist in the division of epidemiology and prevention research at the National Institute on Alcohol Abuse and Alcoholism, the consequences of mixing prescription medications with alcohol can have a variety of effects, some deadly.

"Alcohol can increase blood pressure, which could be counterproductive if one is taking medications to control blood pressure," he explained. "Mixing diuretic medications with alcohol, which is also a diuretic, could contribute to dehydration. Mixing alcohol and other sedatives, like sleeping pills or narcotic pain medications, can cause sleepiness, problems with coordination, and potentially suppress brain stem areas tasked with controlling vital reflexes like breathing, heart rate, and gagging to clear the airway. Alcohol increases insulin levels and lowers blood glucose, so combining alcohol with antidiabetic agents that regulate glucose levels could cause an undesirable drop in blood sugar. And, over time, alcohol can contribute to insulin insensitivity."

"Our findings highlight a major gap in the literature," said Breslow. "We found no US nationally representative data that queried combined use of alcohol with a wide range of prescription medications and yet it appears that a large percentage of people who drink regularly could be at risk of serious alcohol and medication interactions."

Breslow suggested that individuals who drink, particularly the elderly, should be educated about of the risks of combining alcohol with their medications. "We suggest asking one's doctor or pharmacist whether they should avoid alcohol while taking the medications they are prescribed," she said.

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Sleep difficulties in adolescents can predict alcohol, drug problems

A new study has found that sleep difficulties and hours of sleep can predict a number of specific problems, including binge drinking, driving under the influence of alcohol, and risky sexual behavior.

Sleep difficulties and insufficient sleep are common among American youth. Prior research has shown that poor sleep can predict alcohol-related problems and illicit drug use among adolescents and young adults in high-risk samples. A new study has found that sleep difficulties and hours of sleep can predict a number of specific problems, including binge drinking, driving under the influence of alcohol, and risky sexual behavior in a nationally representative sample.

Results will be published in the February 2015 online-only issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"National polls indicate that 27 percent of school-aged children and 45 percent of adolescents do not sleep enough," said Maria M. Wong, professor and director of experimental training in the department of psychology at Idaho State University. "Other studies have shown that about one in 10 adolescents have trouble falling asleep or staying asleep almost every day, or every day, in the previous 12 months." Wong is also the corresponding author for the study.

"This paper is important in that it advances our understanding of the relation of sleep to substance use problems to include not only problems sleeping, that is, trouble falling asleep and/or staying asleep, but also insufficient sleep, addressed here as hours of sleep," added Tim Roehrs, director of research at the Sleep Disorders and Research Center at the Henry Ford Hospital, and one of the first researchers to identify sleep insufficiency as a clinical issue in the 1990s.

"Among normal adults, sleep difficulties and insomnia have predicted onset of alcohol use one year later, and increased risk of any illicit drug use disorder and nicotine dependence 3.5 years later," said Wong. "Among adult alcoholics who received treatment for alcohol dependence, those with insomnia at baseline were more likely to relapse to alcohol use. The association between poor sleep and substance use has also been found in younger age groups. Overtiredness in childhood has predicted lower response inhibition in adolescence, which in turn predicted number of illicit drugs used in young adulthood. Overtiredness in childhood has also directly predicted the presence of binge drinking, blackouts, driving after drinking alcohol, and number of lifetime alcohol problems in young adulthood. The purpose of this study was to examine whether sleep difficulties and hours of sleep prospectively predicted several serious substance-related problems that included binge drinking, driving under the influence of alcohol, and risky sexual behavior."

Wong and her co-authors analyzed data collected via interviews and questionnaires from 6,504 adolescents (52% girls, 48% boys) participating in the National Longitudinal Study of Adolescent Health. Data were collected for three waves -- 1994-1995, 1996, and 2001-2002 -- and study authors used sleep difficulties from a previous wave to predict substance-related problems at a subsequent wave, while controlling for substance-related problems at the previous wave.

"Sleep difficulties at the first wave significantly predicted alcohol-related interpersonal problems, binge drinking, gotten drunk or very high on alcohol, driving under the influence of alcohol, getting into a sexual situation one later regretted due to drinking, and ever using any illicit drugs and drugs-related problems at the second wave," said Wong. "Substance-related problems such as binge drinking, driving under the influence of alcohol, and risky sexual behavior are more important than others due to their association with reckless driving, automobile accidents, physical injuries and even death, as well as risk for sexually transmitted disease and unplanned pregnancy."

"The rate of sleep problems in this sample of adolescents is quite similar to that of adults," added Roehrs, "about 10 percent chronic insomnia and about 30 percent occasional insomnia. This speaks to the underlying biological basis of insomnia. Furthermore, the consequences of sleep difficulty and sleep insufficiency when added to use of alcohol or other substances can impact both medical and behavioral areas. And which is more important depends on whether one focuses on short-term or long-term consequences -- the immediate impact of an automobile accident or reduced future job opportunities because of lost educational engagement."

"Previous studies on adolescents were mostly drawn from high risk samples," noted Wong. "This study has added to the existing literature by establishing the relationship between two sleep variables -- sleep difficulties and hours of sleep -- and the odds of serious alcohol- and drug-related problems in a nationally representative sample."

Both Wong and Roehrs believe that parents can play a significant role regarding their adolescents' sleep habits.

"Parents need to understand their children's sleep schedule, patterns, and habits," said Wong. "If children have sleep difficulties or poor sleep hygiene, it is important for parents to talk to them and find out the factors that may be causing the problems. Parents could explain the importance of sleep to their children, for example, how sleep may affect the development of the brain and thus self-control and behavior. Parents could also help their children keep a regular sleep schedule and monitor/control their children's activities before sleep, for example, no video games or texting after a certain time at night."

"And remember," added Roehrs, "when you monitor the sleep health of your adolescent, there can be two different issues: sleep difficulty and sleep insufficiency."

Wong hopes future research will address how sleep difficulties and deprivation may affect brain mechanisms, which in turn influence control of affect, cognitive processes, and behavior. "Prolonged periods of wakefulness appears to adversely affect the prefrontal cortex or PFC," she said. "PFC regulates affect, attention, and complex cognitive activities. One recent study showed that sleep-deprived subjects experienced a loss of functional connectivity between the amygdala and the medial-PFC compared to controls. Thus, future studies could examine how neural circuitries mediate the effect of sleep problems on self-regulation and risk behavior."

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Genes, environment contribute to personal, peer drinking during adolescence and beyond

Alcohol use typically begins during adolescence, within social contexts, and is often correlated with the drinking of one's peers. A new study of how a person's drinking is related to the alcohol use of their peers from early adolescence through to early adulthood has found that both genetic and environmental factors contribute to the correlation between one's own drinking and peer drinking.

Results will be published in the February 2015 online-only issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"Peers can influence adolescent drinking in different ways," said Alexis C. Edwards, assistant professor in the department of psychiatry at Virginia Commonwealth University as well as corresponding author for the study. "Peer pressure can work in both directions: some kids feel pressured, others are the ones exerting the pressure for whatever reason. Peer pressure doesn't have to be explicit; kids can perceive pressure that's never verbalized. Another way that peers can influence drinking is simply by providing access to alcohol. Furthermore, adolescent drinking behavior often occurs in the context of peer groups rather than in solitary situations. Therefore, it's important not to overlook the role that choice plays in all these scenarios: to varying extents, kids select which peers they hang out with, which in turn has consequences for alcohol use."

"Peer behavior is perhaps the most enduring social correlate of both contemporaneous and subsequent alcohol use, so studies specifically designed to explore the etiology underlying these associations, and particularly those that examine mechanistic processes, are tremendously important to the field," added Shawn J. Latendresse, assistant professor in the department of psychology & neuroscience at Baylor University.

"We have access to a rich twin dataset that uniquely allows us to tease apart the complicated relationships of peer selection and peer influence, all in the context of genetic and environmental influences underlying behavior," said Edwards. "We examined men simply because we only had the necessary data for men. It would be very interesting to see if the same patterns hold among women, because there are some differences in drinking behaviors across the sexes."

Edwards and her colleagues used data collected in Wave Three of the Virginia Adult Twin Study of Psychiatric and Substance Use Disorders. From that larger study of adult Caucasian twins, study authors analyzed data from a sample of 1,790 men, provided through structured clinical interviews that included retrospective reports of their own drinking as well as their peers' alcohol-related behaviors from adolescence into young adulthood, ages 12 to 25 years. The influence of three plausible models of genetic and environmental influences on the relationship between phenotypes was examined over time.

"There seem to be two take-home messages," said Edwards. "First, genetic and environmental factors contribute to the correlation between one's own drinking and their peers' drinking. Second, apart from these shared genetic and environmental liabilities, there are causal processes at play: your own drinking phenotype causes you to select peers based on their drinking, and your peers' drinking influences your own drinking."

"Most notable, from the perspective of developmental science, is the fact that this study provides initial evidence of bidirectional influences among the drinking behaviors of individuals and their peers," added Latendresse. "Yet, despite increasing additive genetic influences across adolescence, the majority of the variance in alcohol consumption continues to be attributable to environmental factors. This is particularly encouraging, as there remains great potential within the research community to identify modifiable aspects of the environment that can then serve as the focus of applied prevention/intervention efforts."

Both Edwards and Latendresse commented on the finding of a clear increase in the influence of genetic factors as the adolescents moved into adulthood, and a corresponding decrease in the influence of shared environmental factors.

"The increase in the relevance of genetic factors is pretty typical," said Edwards. "As we age and gain more autonomy, our behavior is driven more by our own genetic liabilities and we are less influenced by the familial environment."

"In general, as twins mature and become more independent of one another -- for example, attend different schools, live in separate homes -- they tend to share fewer of the influences within their physical and social environments, while their genetic similarities remain constant," added Latendresse. "Of course, unique aspects of the twins' environments are just as influential as their shared biology, and often more so, when it comes to their own alcohol consumption and the perceived consumption of their peers."

"I hope that our study helps clarify the relationship observed between self and peer drinking behaviors across adolescence into adulthood," said Edwards. "But there's no way around the fact that this relationship is complicated. Our contribution is to provide evidence that shared genetic/environmental liabilities and causal processes are at play simultaneously: the association isn't an either/or situation."

Latendresse agreed. "It is also important to note that the increasing role of genes across development that is evidenced in this, and many other studies, might not be as straight forward as it appears. For example, because one's genes generally aren't subject to change, any change in the influence or expression of one's genes is likely 'triggered' by other biological and/or environmental processes. However, within the types of statistical models employed in this study, all of these conditional effects would necessarily be partitioned in with the additive genetic variance. In this way, environmental influence has the potential to be misallocated."

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Pre-sleep drinking disrupts sleep

For individuals who drink before sleeping, alcohol initially acts as a sedative -- marked by the delta frequency electroencephalogram (EEG) activity of Slow Wave Sleep (SWS) -- but is later associated with sleep disruption. Significant reductions in EEG delta frequency activity and power also occur with normal development between the ages of 12 and 16; likewise this is a time when alcohol is commonly consumed for the first time, with dramatic increases in drinking occurring among collage-age individuals. A study of the effects of alcohol on sleep EEG power spectra in college students has found that pre-sleep drinking not only causes an initial increase in SWS-related delta power but also causes an increase in frontal alpha power, which is thought to reflect disturbed sleep.

Results will be published in the February 2015 online-only issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"People likely tend to focus on the commonly reported sedative properties of alcohol, which is reflected in shorter times to fall asleep, particularly in adults, rather than the sleep disruption that occurs later in the night," said Christian L. Nicholas, National Health & Medical Research Council Peter Doherty Research Fellow in the Sleep Research Laboratory at The University of Melbourne as well as corresponding author for the study.

"The reduction in delta frequency EEG activity we see across the ages is thought to represent normal brain maturational processes as the adolescent brain continues to develop to full maturity," said Nicholas. "Although the exact function of non-Rapid Eye Movement (NREM) sleep, and in particular SWS, is a topic of debate, it is thought to reflect sleep need and quality; thus any disruption to this may affect the underlying restorative properties of sleep and be detrimental to daytime functioning."

Nicholas and his colleagues recruited 24 participants (12 female, 12 male), healthy 18- to 21-year-old social drinkers who had consumed less than seven standard drinks per week during the previous 30 days. Each participant underwent two conditions: pre-sleep alcohol as well as a placebo, followed by standard polysomnography with comprehensive EEG recordings.

Results showed that alcohol increased SWS delta power during NREM. However, there was a simultaneous increase in frontal alpha power.

"For individuals researching sleep in the field of alcohol studies," said Nicholas, "our findings indicate that care needs to be taken when interpreting increases in 'visually scored' SWS associated with alcohol consumption. Increases in SWS, which traditionally would be interpreted as a good thing, can be associated with more subtle changes indicating disrupted sleep, such as the increases we observed in alpha activity, which are revealed when more detailed micro-structural components of the sleep electroencephalogram are assessed."

Nicholas explained that the increase in frontal alpha power that occurs as a result of pre-sleep drinking likely reflects a disruption of the normal properties of NREM slow wave sleep.

"Similar increases in alpha-delta activity, which are associated with poor or unrefreshing sleep and daytime function, have been observed in individuals with chronic pain conditions," he said. "Thus, if sleep is being disrupted regularly by pre-sleep alcohol consumption, particularly over long periods of time, this could have significant detrimental effects on daytime wellbeing and neurocognitive function such as learning and memory processes."

Alcohol is not a sleep aid, said Nicholas. "The take-home message here is that alcohol is not actually a particularly good sleep aid even though it may seem like it helps you get to sleep quicker. In fact, the quality of the sleep you get is significantly altered and disrupted."

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Investigations and complaints procedures have a serious impact on doctors' health, risk harming patients, study suggests

Doctors who are the subject of complaints procedures or investigation by the General Medical Council experience high rates of serious depression and anxiety as well as suicidal thoughts, according to a new study.

Four out of five doctors also reported changing the way they treat their patients as a result of either complaints against themselves, or observing a colleague go through a complaints process.

The authors of the research say that by causing psychological ill health and encouraging defensive practice, the processes designed to hold doctors to account are having negative consequences for patients.

The findings come from a survey of 7,926 doctors published in BMJ Open.

Professor Tom Bourne, lead author of the study from the Department of Surgery and Cancer at Imperial College London, said: "Of course it's essential that when things go wrong, the reasons are properly investigated. But this study suggests that the regulatory system we have in the UK has unintended consequences that are not just seriously damaging for doctors, but are also likely to lead to bad outcomes for patients. We think this needs to be looked at carefully by policy makers."

The General Medical Council regulates doctors in the UK and can stop or limit their rights to practise. In 2013 there were more than 8,500 complaints about doctors to the GMC, of which just over 3,000 went on to be investigated. About 80 doctors a year are suspended or erased from the medical register. Apart from those referred to the GMC, many other complaints are investigated through hospitals' internal enquiries.

The study found that doctors who had recently been the subject of a complaint were twice as likely as other doctors to report moderate or severe anxiety, and twice as likely to have thoughts of self-harm. Those referred to the GMC had especially high rates of psychological illness, with 26 per cent reporting moderate to severe depression and 22 per cent moderate to severe anxiety.

"Our data suggests the impact of complaints procedures of all kinds on doctors is often disproportionate to the issue being investigated," said Professor Bourne. "For example the vast majority of doctors referred to the GMC are found to have no case to answer, yet many doctors being investigated show high levels of serious psychological morbidity and we know this impacts on how they treat patients."

Many doctors admitted practicing medicine more defensively as a result of being investigated or witnessing the impact of investigations on colleagues. Eighty-four per cent reported hedging -- overcautious practice such as overprescribing, referring too many patients, or ordering unnecessary tests. Forty-six per cent reported avoidance -- reluctance to take on difficult patients or procedures.

"A key issue that has come out of the study is the apparent impact on patient care of these complaints processes," said Professor Bourne. "Over prescribing or referral and avoiding complex patients or difficult operations because of a fear of complaints or the actions of the regulator is clearly not in the interests of patients, and may increase costs to the NHS. We need a new structure that is transparent, fair and has the confidence of all parties"
 
The study also found that:

-- 20 per cent of doctors felt the complaint against them was a result of them being victimised after whistleblowing.

-- 39 per cent said they felt bullied when going through the complaints process.

-- 27 per cent had more than a month off work as a direct result of the complaints process.

"Our findings are a concern for all of us who want to see a culture within the NHS that is transparent and open, that recognises that honest mistakes can occur, where complaints are learnt from, and where it is safe to speak out about clinical and managerial concerns," said Professor Bourne. "But how likely is it that doctors will have the confidence to put their hand up when regulatory processes can have such negative consequences for both them and their patients?"

Many doctors who took part in the survey felt processes could be improved through greater transparency, managerial competence, and the capacity to act against vexatious complainants.

In December, the GMC published an internal review of 28 cases of suicide by doctors while they were being investigated by the regulator. The report highlighted the need for doctors under investigation to feel 'innocent until proven guilty' and stated such processes may stigmatise and 'create a culture of fear and discrimination'.

"The data from our study on over 7000 doctors has limitations, but based on the findings one must question whether a wider external review of the impact of the regulator and the complaints 'pyramid', beyond the narrow remit of 28 doctors who actually did commit suicide, should be carried out," said Professor Bourne.

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Three nearly Earth-size planets found orbiting nearby star: One in 'Goldilocks' zone

This artistic impression shows NASA's planet-hunting Kepler spacecraft operating in a new mission profile called K2.

A multinational, multi-institution team of researchers led by University of Arizona scientist Ian Crossfield has found a star with three planets, one of which may have temperatures moderate enough for liquid water -- and maybe even life -- to exist.

NASA's Kepler Space Telescope, despite being hobbled by the loss of critical guidance systems, has discovered a star with three planets only slightly larger than Earth. The outermost planet orbits in the "Goldilocks" zone, a region where surface temperatures could be moderate enough for liquid water and perhaps life, to exist.

The star, EPIC 201367065, is a cool red M-dwarf about half the size and mass of our own sun. At a distance of 150 light years, the star ranks among the top 10 nearest stars known to have transiting planets. The star's proximity means it's bright enough for astronomers to study the planets' atmospheres to determine whether they are like Earth's atmosphere and possibly conducive to life.

"A thin atmosphere made of nitrogen and oxygen has allowed life to thrive on Earth. But nature is full of surprises. Many exoplanets discovered by the Kepler mission are enveloped by thick, hydrogen-rich atmospheres that are probably incompatible with life as we know it," said Ian Crossfield, the University of Arizona astronomer who led the study.

A paper describing the find by astronomers at the University of Arizona, the University of California, Berkeley, the University of Hawaii, Manoa, and other institutions has been submitted to Astrophysical Journal and is freely available on the arXiv website . NASA and the National Science Foundation funded the research.

Co-authors of the paper include Joshua Schlieder of NASA Ames Research Center and colleagues from Germany, the United Kingdom and the U.S.

The three planets are 2.1, 1.7 and 1.5 times the size of Earth. The smallest and outermost planet, at 1.5 Earth radii, orbits far enough from its host star that it receives levels of light from its star similar to those received by Earth from the sun, said UC Berkeley graduate student Erik Petigura. He discovered the planets Jan. 6 while conducting a computer analysis of the Kepler data NASA has made available to astronomers. In order from farthest to closest to their star, the three planets receive 10.5, 3.2 and 1.4 times the light intensity of Earth, Petigura calculated.

"Most planets we have found to date are scorched. This system is the closest star with lukewarm transiting planets," Petigura said. "There is a very real possibility that the outermost planet is rocky like Earth, which means this planet could have the right temperature to support liquid water oceans."

University of Hawaii astronomer Andrew Howard noted that extrasolar planets are discovered by the hundreds these days, though many astronomers are left wondering if any of the newfound worlds are really like Earth. The newly discovered planetary system will help resolve this question, he said.

"We've learned in the past year that planets the size and temperature of Earth are common in our Milky Way galaxy," Howard said. "We also discovered some Earth-size planets that appear to be made of the same materials as our Earth, mostly rock and iron."

Kepler's K2 mission

After Petigura found the planets in the Kepler light curves, the team quickly employed telescopes in Chile, Hawaii and California to characterize the star's mass, radius, temperature and age. Two of the telescopes involved, the Automated Planet Finder on Mount Hamilton near San Jose, California, and the Keck Telescope on Mauna Kea, Hawaii, are University of California facilities.

The next step will be observations with other telescopes, including the Hubble Space Telescope, to take the spectroscopic fingerprint of the molecules in the planetary atmospheres. If these warm, nearly Earth-size planets have puffy, hydrogen-rich atmospheres, Hubble will see the telltale signal, Petigura said.

The discovery is all the more remarkable, he said, because the Kepler telescope lost two reaction wheels that kept it pointing at a fixed spot in space.

Kepler was reborn in 2014 as 'K2' with a clever strategy of pointing the telescope in the plane of Earth's orbit, the ecliptic, to stabilize the spacecraft. Kepler is now back to mining the cosmos for planets by searching for eclipses or "transits," as planets pass in front of their host stars and periodically block some of the starlight.

"This discovery proves that K2, despite being somewhat compromised, can still find exciting and scientifically compelling planets," Petigura said. "This ingenious new use of Kepler is a testament to the ingenuity of the scientists and engineers at NASA. This discovery shows that Kepler can still do great science."

Kepler sees only a small fraction of the planetary systems in its gaze: only those with orbital planes aligned edge-on to our view from Earth. Planets with large orbital tilts are missed by Kepler. A census of Kepler planets the team conducted in 2013 corrected statistically for these random orbital orientations and concluded that one in five sun-like stars in the Milky Way Galaxy have Earth-size planets in the habitable zone. Accounting for other types of stars as well, there may be 40 billion such planets galaxy wide.

The original Kepler mission found thousands of small planets, but most of them were too faint and far away to assess their density and composition and thus determine whether they were high-density, rocky planets like Earth or puffy, low-density planets like Uranus and Neptune. Because the star EPIC-201 is nearby, these mass measurements are possible. The host star, an M-dwarf, is less intrinsically bright than the sun, which means that its planets can reside close to the host-star and still enjoy lukewarm temperatures.

According to Howard, the system most like that of EPIC-201 is Kepler-138, an M-dwarf star with three planets of similar size, though none are in the habitable zone.

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