Using electrical brain recordings and a form of magnetic stimulation, Rajesh Rao sent a brain signal to Andrea Stocco on the other side of the UW campus, causing Stocco's finger to move on a keyboard.While researchers at Duke University have demonstrated brain-to-brain communication between two rats, and Harvard researchers have demonstrated it between a human and a rat, Rao and Stocco believe this is the first demonstration of human-to-human brain interfacing.

"The Internet was a way to connect computers, and now it can be a way to connect brains," Stocco said. "We want to take the knowledge of a brain and transmit it directly from brain to brain."

The researchers captured the full demonstration on video recorded in both labs. The version available at the end of this story has been edited for length. Rao, a UW professor of computer science and engineering, has been working on brain-computer interfacing (BCI) in his lab for more than 10 years and just published a textbook on the subject. In 2011, spurred by the rapid advances in BCI technology, he believed he could demonstrate the concept of human brain-to-brain interfacing. So he partnered with Stocco, a UW research assistant professor in psychology at the UW's Institute for Learning & Brain Sciences.

On Aug. 12, Rao sat in his lab wearing a cap with electrodes hooked up to an electroencephalography machine, which reads electrical activity in the brain. Stocco was in his lab across campus wearing a purple swim cap marked with the stimulation site for the transcranial magnetic stimulation coil that was placed directly over his left motor cortex, which controls hand movement.The team had a Skype connection set up so the two labs could coordinate, though neither Rao nor Stocco could see the Skype screens.Rao looked at a computer screen and played a simple video game with his mind. When he was supposed to fire a cannon at a target, he imagined moving his right hand (being careful not to actually move his hand), causing a cursor to hit the "fire" button. Almost instantaneously, Stocco, who wore noise-canceling earbuds and wasn't looking at a computer screen, involuntarily moved his right index finger to push the space bar on the keyboard in front of him, as if firing the cannon. Stocco compared the feeling of his hand moving involuntarily to that of a nervous tic.

                                       

"It was both exciting and eerie to watch an imagined action from my brain get translated into actual action by another brain," Rao said. "This was basically a one-way flow of information from my brain to his. The next step is having a more equitable two-way conversation directly between the two brains."

The technologies used by the researchers for recording and stimulating the brain are both well-known. Electroencephalography, or EEG, is routinely used by clinicians and researchers to record brain activity noninvasively from the scalp. Transcranial magnetic stimulation, or TMS, is a noninvasive way of delivering stimulation to the brain to elicit a response. Its effect depends on where the coil is placed; in this case, it was placed directly over the brain region that controls a person's right hand. By activating these neurons, the stimulation convinced the brain that it needed to move the right hand.Computer science and engineering undergraduates Matthew Bryan, Bryan Djunaedi, Joseph Wu and Alex Dadgar, along with bioengineering graduate student Dev Sarma, wrote the computer code for the project, translating Rao's brain signals into a command for Stocco's brain.

"Brain-computer interface is something people have been talking about for a long, long time," said Chantel Prat, assistant professor in psychology at the UW's Institute for Learning & Brain Sciences, and Stocco's wife and research partner who helped conduct the experiment. "We plugged a brain into the most complex computer anyone has ever studied, and that is another brain."At first blush, this breakthrough brings to mind all kinds of science fiction scenarios. Stocco jokingly referred to it as a "Vulcan mind meld." But Rao cautioned this technology only reads certain kinds of simple brain signals, not a person's thoughts. And it doesn't give anyone the ability to control your actions against your will.

Both researchers were in the lab wearing highly specialized equipment and under ideal conditions. They also had to obtain and follow a stringent set of international human-subject testing rules to conduct the demonstration.

"I think some people will be unnerved by this because they will overestimate the technology," Prat said. "There's no possible way the technology that we have could be used on a person unknowingly or without their willing participation."

Stocco said years from now the technology could be used, for example, by someone on the ground to help a flight attendant or passenger land an airplane if the pilot becomes incapacitated. Or a person with disabilities could communicate his or her wish, say, for food or water. The brain signals from one person to another would work even if they didn't speak the same language.Rao and Stocco next plan to conduct an experiment that would transmit more complex information from one brain to the other. If that works, they then will conduct the experiment on a larger pool of subjects.

Scientists now have made the first-ever accurate determination of a solid-state triple point in a substance called vanadium dioxide, which is known for switching rapidly -- in as little as one 10-trillionth of a second -- from an electrical insulator to a conductor, and thus could be useful in various technologies.

"These solid-state triple points are fiendishly difficult to study, essentially because the different shapes of the solid phases makes it hard for them to match up happily at their interfaces," said David Cobden, a University of Washington physics professor."There are, in theory, many triple points hidden inside a solid, but they are very rarely probed.".In 1959, researchers at Bell Laboratories discovered vanadium dioxide's ability to rearrange electrons and shift from an insulator to a conductor, called a metal-insulator transition. Twenty years later it was discovered that there are two slightly different insulating phases.

The new research shows that those two insulating phases and the conducting phase in solid vanadium dioxide can coexist stably at 65 degrees Celsius, give or take a tenth of a degree (65 degrees C is equal to 149 degrees Fahrenheit).To find that triple point, Cobden's team stretched vanadium dioxide nanowires under a microscope. The team had to build an apparatus to stretch the tiny wires without breaking them, and it was the stretching that allowed the observation of the triple point, Cobden said.

It turned out that when the material manifested its triple point, no force was being applied -- the wires were not being stretched or compressed.The researchers originally set out simply to learn more about the phase transition and only gradually realized that the triple point was key to it, Cobden said. That process took several years, and then it took a couple more to design an experiment to pin down the triple point."No previous experiment was able to investigate the properties around the triple point," he said.

He regards the work as "just a step, but a significant step" in understanding the metal-insulator transition in vanadium dioxide. That could lead to development of new types of electrical and optical switches, Cobden said, and similar experiments could lead to breakthroughs with other materials."If you don't know the triple point, you don't know the basic facts about this phase transition," he said. "You will never be able to make use of the transition unless you understand it better."

The discovery alters understanding of the chemistry that moves manganese and other elements, like oxygen and carbon, through the natural world. Manganese is an essential nutrient for most organisms and helps plants produce oxygen during photosynthesis.

"You wouldn't think manganese is that important, but without manganese, we wouldn't have the molecular oxygen that we breathe," said study co-author George Luther, Maxwell P. and Mildred H. Harrington Professor of Oceanography in the School of Marine Science and Policy within UD's College of Earth, Ocean, and Environment.

Manganese is present in the environment in three forms -- manganese(II), manganese(III) and manganese(IV) -- the difference related to the oxidation state, or number of electrons present. When elements lose or gain an electron, the oxidation state changes in a "redox reaction," like when iron turns into rust by losing electrons to oxygen in air.

The second-most common metal in Earth's crust, manganese rapidly changes between oxidation states while reacting with other elements in the environment.Traditionally, manganese(II) and manganese(IV) were believed to be the dominant forms in aquatic environments. But in the mid-2000s, Luther found in a surprising result that manganese(III) was also present in a Black Sea "transition zone," an area where oxygen levels are relatively high near the surface but gradually diminish deeper down in the water.

Suspecting that this intermediary form was far more widespread than the somewhat unique conditions of the Black Sea, he and his Canadian colleagues Bjørn Sundby of the University of Quebec at Rimouski and Al Mucci of McGill University, whom he has worked with more than 20 years, set out for the largest estuary in the world: the Gulf of Saint Lawrence off the southeast corner of Canada.There they pulled up samples of mud from the seafloor, where in the top few inches of sediment, there is also a transition zone of diminishing oxygen amounts. Andrew Madison, lead author on the Science paper and Luther's former graduate student, used a new technique to differentiate between manganese forms.

"It was a bit frustrating, and I spent about two and a half years working through methodological challenges and complications," said Madison, who finished his doctorate last year and now works as geochemist at Golder Associates Inc. in New Jersey. "But it was also pretty rewarding when I finally got something to work."

His results showed that manganese(III) comprised up to 90 percent of the total manganese present in the Canadian study sites. The implication is that the metal is found in other marine environments where there is a gradation of oxygen concentrations, whether in the water column of the Black Sea, sediment in the Gulf of Lawrence or a Delaware salt marsh."We saw it all through the Saint Laurentian Estuary where we studied," Luther said. "We did some work in a local salt marsh and found it. Wherever we've been able to look for it, we've found it. By implication, it should be found in all ocean sediments."

The findings help explain anomalies in manganese models that have puzzled scientists. Other researchers studying manganese did not make specific measurements for manganese(II) versus manganese(III), Luther said. Rather, they measured total dissolved manganese and assumed it was the former.This missing link in the manganese cycle may shed light on the complex connections between the biology, geology and chemistry -- called biogeochemistry -- in ocean environments.The biogeochemistry of marine sediments revolves around organic matter, like bits of dead algae, that fall through the water to the bottom of the ocean. Bacteria consume that debris, setting off a chain of reactions.

"In sediments, bacteria prefer to consume molecular oxygen and nitrate first due to their high energy gain," Madison said. "After those are consumed, bacteria then couple organic matter oxidation to manganese oxide reduction, which can produce soluble manganese(III)."In their paper, the researchers call for the conceptual model of the sedimentary redox cycle to be revised to include dissolved manganese(III).

"Manganese is helpful to produce organic matter in the surface waters through photosynthesis," Luther said. "But in the sediments, the higher oxidation state manganese is used to decompose organic matter. So it's a really interesting cycle."Luther, his students and his Oregon Health & Science University collaborator, Brad Tebo, plan to return to Canada to continue work on the microbiology and chemistry of the processes, hopefully to find out which organisms are helping the manganese oxidation process.

Since the 1960s, it has been known that groundwater resources in certain provinces of China are contaminated with arsenic. Estimates of the numbers of affected people have risen year by year. In the most recent survey -- conducted by the Chinese Ministry of Health between 2001 and 2005 -- more than 20,000 (5%) of the 445,000 wells tested showed arsenic concentrations higher than 50 µg/L. According to official estimates, almost 6 million people consume drinking water with an arsenic content of more than 50 µg/L and almost 15 million are exposed to concentrations exceeding 10 µg/L (the guideline value recommended by the WHO).

Given the sheer size of China and the time and expense involved in testing for arsenic contamination, several more decades would probably be required to screen all of the millions of groundwater wells. Accordingly, a group of researchers from Eawag and the China Medical University in Shenyang developed a statistical risk model making use of existing data on geology, soil characteristics and topographic features. This model was calibrated using available arsenic measurements. The predictions of unsafe or safe areas showed a high level of agreement, both for known high-risk areas and for areas where elevated arsenic levels had been ruled out by sampling campaigns.

In addition, large areas have now been identified as potentially at risk, such as the basins of the Tarim (Xinjiang), Ejina (Inner Mongolia) and Heihe (Gansu), or the North China Plain (Henan and Shandong). Arsenic concentrations above 10 µg/L are predicted for a total area of 580,000 km2. When these results were combined with the latest available population data, it was found that almost 20 million people across China live in high-risk areas.

Geochemist Annette Johnson concedes: "This figure may be an overestimate, as we lack reliable information on the number of people with treated water sup-plies." But in the long term, she adds, China will remain dependent on groundwater as a source of drinking water, particularly in the arid provinces. The risk model shows where conventional groundwater quality monitoring efforts are best focussed: "Our method permits more targeted sampling cam-paigns and saves time in identifying populations at risk. The Chinese authorities are adopting our maps in the national monitoring programme." Johnson is convinced that the model could also be used in other countries where groundwater is known or suspected to be contaminated with arsenic -- for example, in Africa or in central Asia, where risk assessments for arsenic contamination have not yet been performed.

Arsenic background

Arsenic is one of the most common inorganic contaminants found in drinking water worldwide. This metalloid occurs as a natural component of sediments, with small quantities being dissolved in groundwater as a result of weathering. The inorganic salts of arsenic are tasteless and odourless, but highly toxic to humans. If ingested over long periods, even low concentrations can cause damage to health, including hyperpigmentation of the skin, hyperkeratosis on the palms and soles, disorders of liver, cardiovascular and kidney function, and various types of cancer.

Problems arise from the fact that firstly, arsenic concentrations can vary widely at the local level and, secondly, people in many areas are completely unaware of the risk because their groundwater wells have never been screened for arsenic. Concentrations below 10 µg/L are considered safe. This concentration is therefore recommended by the World Health Organi-zation as a guideline value for arsenic in drinking water. In China, the standard guideline has just recently changed from 50 µg/L to 10 µg/L. In many other studies, e.g. at various sites in Inner Mongolia, arsenic concentrations of more than 100 µg/L and up to 1500 µg/L have been measured.

The movies promise to give astronomers a better understanding of how active black holes shape galaxy evolution. While matter drawn completely into a black hole cannot escape its enormous gravitational pull, most infalling material drawn toward it first joins an orbiting region known as an accretion disk encircling the black hole. Magnetic fields surrounding the black hole are thought to entrain some of this ionized gas, ejecting it as very high-velocity jets.

"Central supermassive black holes are a key component in all big galaxies," said Eileen T. Meyer of the Space Telescope Science Institute (STScI) in Baltimore, Md., the Hubble study's lead author. "Most of these black holes are believed to have gone through an active phase, and black-hole-powered jets from this active phase play a key role in the evolution of galaxies. By studying the details of this process in the nearest galaxy with an optical jet, we can hope to learn more about galaxy formation and black hole physics in general."

The Hubble movies reveal for the first time that the jet's river of plasma travels in a spiral motion. This motion is considered strong evidence that the plasma may be traveling along a magnetic field, which the team thinks is coiled like a helix. The magnetic field is believed to arise from a spinning accretion disk of material around a black hole. Although the magnetic field cannot be seen, its presence is inferred by the confinement of the jet along a narrow cone emanating from the black hole.

"We analyzed several years' worth of Hubble data of a relatively nearby jet, which allowed us to see lots of details," Meyer said. "The only reason you see the distant jet in motion at all over just a few years is because it is traveling very fast."

Meyer found evidence for the magnetic field's suspected helical structure in several locations along the jet. In the outer part of the M87 jet, for example, one bright gas clump, called knot B, appears to zigzag, as if it were moving along a spiral path. Several other gas clumps along the jet also appear to loop around an invisible structure. "Past observations of black hole jets couldn't distinguish between radial motion and side-to-side motion, so they didn't provide us with detailed information of the jet's behavior," Meyer explained.

M87 resides at the center of the neighboring Virgo cluster of roughly 2,000 galaxies, located 50 million light-years away. The galaxy's monster black hole is several billion times more massive than our Sun.

In addition, the Hubble data provided information on why the jet is composed of a long string of gas blobs, which appear to brighten and dim over time.

"The jet structure is very clumpy. Is this a ballistic effect, like cannonballs fired sequentially from a cannon?" Meyer asked. "Or, is there some particularly interesting physics going on, such as a shock that is magnetically driven?"

Meyer's team found evidence for both scenarios. "We found things that move quickly," Meyer said. "We found things that move slowly. And, we found things that are stationary. This study shows us that the clumps are very dynamic sources."

The research team spent eight months analyzing 400 observations from Hubble's Wide Field Planetary Camera 2 and Advanced Camera for Surveys. The observations were taken from 1995 to 2008. Several team members, however, have been observing M87 for 20 years. Only Hubble's sharp vision allowed the research team to measure the jet's slight motion in the sky over 13 years. Meyer's team also measured features in the hot plasma as small as 20 light-years wide.

It's too soon to tell whether all black-hole-powered jets behave like the one in M87. That's why Meyer plans to use Hubble to study three more jets. "It's always dangerous to have exactly one example because it could be a strange outlier," Meyer said. "The M87 black hole is justification for looking at more jets."

Functional MRI scanners have been used in cognition research primarily to determine which brain areas are active while test subjects perform a specific task. The question is simple: is a particular brain region on or off? A research group at the Donders Institute for Brain, Cognition and Behaviour at Radboud University has gone a step further: they have used data from the scanner to determine what a test subject is looking at.
The researchers 'taught' a model how small volumes of 2x2x2 mm from the brain scans -- known as voxels -- respond to individual pixels. By combining all the information about the pixels from the voxels, it became possible to reconstruct the image viewed by the subject. The result was not a clear image, but a somewhat fuzzy speckle pattern. In this study, the researchers used hand-written letters.

Prior knowledge improves model performance

'After this we did something new', says lead researcher Marcel van Gerven. 'We gave the model prior knowledge: we taught it what letters look like. This improved the recognition of the letters enormously. The model compares the letters to determine which one corresponds most exactly with the speckle image, and then pushes the results of the image towards that letter. The result was the actual letter, a true reconstruction.'

'Our approach is similar to how we believe the brain itself combines prior knowledge with sensory information. For example, you can recognise the lines and curves in this article as letters only after you have learned to read. And this is exactly what we are looking for: models that show what is happening in the brain in a realistic fashion. We hope to improve the models to such an extent that we can also apply them to the working memory or to subjective experiences such as dreams or visualisations. Reconstructions indicate whether the model you have created approaches reality.'

Improved resolution; more possibilities
'In our further research we will be working with a more powerful MRI scanner,' explains Sanne Schoenmakers, who is working on a thesis about decoding thoughts. 'Due to the higher resolution of the scanner, we hope to be able to link the model to more detailed images. We are currently linking images of letters to 1200 voxels in the brain; with the more powerful scanner we will link images of faces to 15,000 voxels.'

Researchers at MIT have discovered an Earth-sized exoplanet named Kepler 78b that whips around its host star in a mere 8.5 hours -- one of the shortest orbital periods ever detected. The planet is extremely close to its star -- its orbital radius is only about three times the radius of the star -- and the scientists have estimated that its surface temperatures may be as high as 3,000 degrees Kelvin, or more than 5,000 degrees Fahrenheit. In such a scorching environment, the top layer of the planet is likely completely melted, creating a massive, roiling ocean of lava.

What's most exciting to scientists is that they were able to detect light emitted by the planet -- the first time that researchers have been able to do so for an exoplanet as small as Kepler 78b. This light, once analyzed with larger telescopes, may give scientists detailed information about the planet's surface composition and reflective properties.

Kepler 78b is so close to its star that scientists hope to measure its gravitational influence on the star. Such information may be used to measure the planet's mass, which could make Kepler 78b the first Earth-sized planet outside our own solar system whose mass is known.

The researchers reported their discovery of Kepler 78b in The Astrophysical Journal.In a separate paper, published in Astrophysical Journal Letters, members of that same group, along with others at MIT and elsewhere, observed KOI 1843.03, a previously discovered exoplanet with an even shorter orbital period: just 4 1/4 hours. The group, led by physics professor emeritus Saul Rappaport, determined that in order for the planet to maintain its extremely tight orbit around its star, it would have to be incredibly dense, made almost entirely of iron -- otherwise, the immense tidal forces from the nearby star would rip the planet to pieces.

"Just the fact that it's able to survive there implies that it's very dense," says Josh Winn, an associate professor of physics at MIT, and co-author on both papers. "Whether nature actually makes planets that are dense enough to survive even closer in, that's an open question, and would be even more amazing."

In their discovery of Kepler 78b, the team that wrote the Astrophysical Journal paper looked through more than 150,000 stars that were monitored by the Kepler Telescope, a NASA space observatory that surveys a slice of the galaxy. Scientists are analyzing data from Kepler in hopes of identifying habitable, Earth-sized planets.The goal for Winn and his colleagues was to look for Earth-sized planets with very short orbital periods.

"We've gotten used to planets having orbits of a few days," Winn says. "But we wondered, what about a few hours? Is that even possible? And sure enough, there are some out there."

To find them, the team analyzed light data from thousands of stars, looking for telltale dips indicating that a planet may periodically pass in front of a star.

Picking out these tiny dips among tens of thousands of light curves is typically a time-intensive ordeal. To speed the process along, the group devised a more automated approach, applying a basic mathematical method known as the Fourier transform to the large dataset. The method essentially whittles the field to those light curves that are periodic, or that exhibit a repetitive pattern.

Stars that host orbiting planets may display periodic dips of light each time a planet crosses, or transits, the star. But there are other periodic stellar phenomena that can affect light emission, such as a star eclipsing another star. To pick out those signals associated with actual planets, physics graduate student Roberto Sanchis-Ojeda searched through the set of periodic light curves, looking for frequent smaller dips in the data midway between the planetary transits.

The group was able to detect the light given off by the planet by measuring the amount by which the overall light dimmed each time the planet passed behind the star. The researchers posit that the planet's light is possibly a combination of radiation from its heated surface and light reflected by surface materials, such as lava and atmospheric vapor.

"I was just looking by eye, and all of a sudden I see this extra drop of light right when it was expected, and it was really beautiful," Sanchis-Ojeda recalls. "I thought, we're actually seeing the light from the planet. It was a really exciting moment."

From their measurements of Kepler 78b, the team determined that the planet is about 40 times closer to its star than Mercury is to our sun. The star around which Kepler 78b orbits is likely relatively young, as it rotates more than twice as fast as the sun -- a sign that the star has not had as much time to slow down.
While it is about the size of Earth, Kepler 78b is most certainly not habitable, due to its extreme proximity to its host star."You'd have to really stretch your imagination to imagine living on a lava world," Winn says. "We certainly wouldn't survive there."But this doesn't entirely rule out the possibility of other habitable, short-period planets. Winn's group is now looking for exoplanets that orbit brown dwarfs -- cold, almost-dead stars that somehow failed to ignite.

"If you're around one of those brown dwarfs, then you can get as close in as just a few days," Winn says. "It would still be habitable, at the right temperature."

This fossil find -- the oldest ancestor in the multituberculate family tree -- represents a newly discovered species known as Rugosodon eurasiaticus. The nearly complete skeleton provides critical insights into the traits that helped such multituberculates thrive in their day. For example, the fossil reveals teeth that were adapted to gnawing plants and animals alike, as well as ankle joints that were highly adept at rotation.

In light of these findings, researchers suggest that R. eurasiaticus paved the way for later plant-eating and tree-dwelling mammals.Chong-Xi Yuan from the Chinese Academy of Geological Sciences in Beijing, China, along with Chinese and American colleagues, report their analysis of the fossil in the 16 August issue of Science.

The multituberculates flourished during the Cretaceous era, which ended over 60 million years ago. Much like today's rodents, they filled an extremely wide variety of niches -- below the ground, on the ground and in the trees -- and this new fossil, which resembles a small rat or a chipmunk, possessed many of the adaptations that subsequent species came to rely upon, the researchers say.

"The later multituberculates of the Cretaceous [era] and the Paleocene [epoch] are extremely functionally diverse: Some could jump, some could burrow, others could climb trees and many more lived on the ground," explained Zhe-Xi Luo, a co-author of the Science report. "The tree-climbing multituberculates and the jumping multituberculates had the most interesting ankle bones, capable of 'hyper-back-rotation' of the hind feet."

"What is surprising about this discovery is that these ankle features were already present in Rugosodon -- a land-dwelling mammal," he said. (Such highly mobile ankle joints are normally associated with the foot functions of animals that are exclusively tree-dwellers -- those that navigate uneven surfaces.)

Additionally, R. eurasiaticus could eat many different types of food, according to the researchers. The fossil -- particularly its dentition, which reveals teeth designed for shearing plant matter -- confirms a 2012 analysis of tooth types that suggested multituberculates consumed an animal-dominated diet for much of their existence, later diversifying to a plant-dominated one.

Multituberculates arose in the Jurassic period and went extinct in the Oligocene epoch, occupying a diverse range of habitats for more than 100 million years before they were out-competed by more modern rodents. By the end of their run on the planet, multituberculates had evolved complex teeth that allowed them to enjoy vegetarian diets and unique locomotive skills that enabled them to traverse treetops. Both adaptations helped them to become dominant among their contemporaries.

The fossilized R. eurasiaticus that Yuan and his team unearthed was preserved in lake sediments, suggesting that the creature may have lived on the shores. However, the researchers say that the ankle joints of this early multituberculate were already highly mobile and its teeth were already oriented for an omnivorous diet. Based on their findings, the researchers suggest that such adaptations must have arisen very early in the evolution of the order, setting the stage for the major diversification of rodent-like mammals that ensued.

The discovery of R. eurasiaticus also extends the distribution of certain multituberculates from Europe to Asia during the Late Jurassic period, the researchers say.

"This new fossil from eastern China is very similar to the Late Jurassic fossil teeth of multituberculates from Portugal in western Europe," explained Dr. Luo. "This suggests thatRugosodon and its closely related multituberculates had a broad paleogreographic distribution and dispersals back-and-forth across the entire Eurasian continent."

Carrying Earthly greetings on a gold plated phonograph record and still-operational scientific instruments -- including the Low Energy Charged Particle detector designed, built and overseen, in part, by UMD's Space Physics Group -- NASA's Voyager 1 has traveled farther from Earth than any other human-made object. And now, these researchers say, it has begun the first exploration of our galaxy beyond the Sun's influence.

"It's a somewhat controversial view, but we think Voyager has finally left the Solar System, and is truly beginning its travels through the Milky Way," says UMD research scientist Marc Swisdak, lead author of a new paper published online this week in The Astrophysical Journal Letters. Swisdak and fellow plasma physicists James F. Drake, also of the University of Maryland, and Merav Opher of Boston University have constructed a model of the outer edge of the Solar System that fits recent observations, both expected and unexpected.

Their model indicates Voyager 1 actually entered interstellar space a little more than a year ago, a finding directly counter to recent papers by NASA and other scientists suggesting the spacecraft was still in a fuzzily-defined transition zone between the Sun's sphere of influence and the rest of the galaxy.

But why the controversy?

At issue is what the boundary-crossing should look like to Earth-bound observers 11 billion miles (18 billion kilometers) away. The Sun's envelope, known as the heliosphere, is relatively well-understood as the region of space dominated by the magnetic field and charged particles emanating from our star. The heliopause transition zone is both of unknown structure and location. According to conventional wisdom, we'll know we've passed through this mysterious boundary when we stop seeing solar particles and start seeing galactic particles, and we also detect a change in the prevailing direction of the local magnetic field.

NASA scientists recently reported that last summer, after eight years of travel through the outermost layer of the heliosphere, Voyager 1 recorded "multiple crossings of a boundary unlike anything previously observed." Successive dips in, and subsequent recovery of, solar particle counts caught researchers' attention. The dips in solar particle counts corresponded with abrupt increases in galactic electrons and protons. Within a month, solar particle counts disappeared, and only galactic particle counts remained. Yet Voyager 1 observed no change in the direction of the magnetic field.

To explain this unexpected observation, many scientists theorize that Voyager 1 has entered a "heliosheath depletion region," but that the probe is still within the confines of the heliosphere. Swisdak and colleagues, who are not part of the Voyager 1 mission science teams, say there is another explanation.

In previous work, Swisdak and Drake have focused on magnetic reconnection, or the breaking and reconfiguring of close and oppositely-directed magnetic field lines. It's the phenomenon suspected to lurk at the heart of solar flares, coronal mass ejections and many of the sun's other dramatic, high-energy events. The UMD researchers argue that magnetic reconnection is also key to understanding NASA's surprising data.

Though often depicted as a bubble encasing the heliosphere and its contents, the heliopause is not a surface neatly separating "outside" and "inside." In fact, Swisdak, Drake and Opher assert that the heliopause is both porous to certain particles and layered with complex magnetic structure. Here, magnetic reconnection produces a complex set of nested magnetic "islands," self-contained loops which spontaneously arise in a magnetic field due to a fundamental instability. Interstellar plasma can penetrate into the heliosphere along reconnected field lines, and galactic cosmic rays and solar particles mix vigorously.

Most interestingly, drops in solar particle counts and surges in galactic particle counts can occur across "slopes" in the magnetic field, which emanate from reconnection sites, while the magnetic field direction itself remains unchanged. This model explains observed phenomena from last summer, and Swisdak and his colleagues suggest that Voyager 1 actually crossed the heliopause on July 27, 2012.

On occasion of India's Independence Day......

Here are some facts...

Fact 1: There were 562 princely states in India at the time of independence. 560 of these states joined India and the remaining two (Junagadh and Hyderabad) were annexed by the military.

Fact 2: After India’s independence from Britain, Portugal amended its constitution and declared Goa as a Portuguese state. Indian troops invaded Goa on December 19, 1961. The former USSR vetoed a resolution submitted by the United States of America and the United Kingdom condemning this invasion.

Fact 3: One of the founders of the Indian National Congress (one of the parties primarily responsible for India’s independence) was Allan Octavian Hume (a British citizen). He is also considered to be the “father of Indian Ornithology”. The other founding members are Dadabhai Naoroji, Dinshaw Wacha, Womesh Chandra Bonnerjee, Surendranath Banerjee, Monomohun Ghose and William Wedderburn.

Fact 4: A drafting committee was set up on 29th August, 1947 to draft the Indian constitution. The final version of the constitution came into effect on January 26, 1950 (Republic Day of India). During the emergency imposed by Indira Gandhi in 1976, our constitution was amended and the word “socialist” added to the preamble to the constitution. Our founding fathers never intended India to be a socialist country.

The new approach to manipulating light, conducted by a group from France's Université de Nice-Sophia Antipolis and China's Xiamen University, uses little power, does not require an external electrical field, and operates at room temperature, making it more practical than many other slow light experiments. Putting the brakes on light can help scientists compare the characteristics of different light pulses more easily, which in turn can help them build highly sensitive instruments to measure extremely slow speeds and small movements, says Umberto Bortolozzo, one of the authors on the Optics Express paper. In a second paper, also published today and appearing in OSA's journal Optics Letters, Bortolozzo and colleagues from the Université de Nice-Sophia Antipolis and the University of Rochester describe an instrument that uses slow light to measure speeds less than one trillionth of a meter per second.

Scientists have known for a long time that a wave packet of light becomes more sluggish when it travels through matter, but the magnitude of this slow-down in typical materials such as glass or water is less than a factor of two. "The question is: can we do something to the matter in order to make light slow down much more considerably?" says Bortolozzo.

The key to achieving a significant drop-off in speed is to take advantage of the fact that when light travels as a pulse it is really a collection of waves, each having a slightly different frequency, says Bortolozzo. However, all the waves in the pulse must travel together. Scientists can design materials to be like obstacles courses that "trip up" some of the waves more than others. In order to exit the material together, the pulse must wait until it can reconstitute itself.

Other research groups have manipulated the properties of atomic vapors or crystal lattices to significantly slow light and, under certain circumstances, to temporarily "stop" it inside the medium. Bortolozzo's team instead used a liquid crystal similar to the materials used in LCD television and computer displays that could operate in a simple setup, does not require external voltages or magnetic fields, and works at room temperature and with very low optical power. They added a chemical component that twisted the liquid crystal molecules into a helical shape and then added dye molecules that nestled in the helical structures. The dye molecules change their shape when irradiated by light, altering the optical properties of the material and hence changing the relative velocities of the different wave components of the light pulse as it travelled through. In addition, the helical structure of the liquid crystal matrix ensures a long lifetime of the shape-shifted dyes, which makes it possible to "store" a light pulse in the medium and later release it on demand.

Although one of the ultimate goals of slow light research is to find a way to slow and store light pulses for optical communications, the long length of the light pulses used by Bortolozzo's team make such an application impractical. However, Bortolozzo says the team's technique is well suited to sensing and interferometry applications. In the Optics Letters,paper Bortolozzo and colleagues demonstrate how slow light can be used to build a highly sensitive instrument that works on a principle similar to the concept behind a police officer's radar gun. Radar guns catch speeders by detecting a shift in the frequency of radio waves (called a Doppler shift) that can be used to determine a car's velocity. Bortolozzo's team used slow light to detect a very slight Doppler shift in a pair of light beams.

The approach "allows us to measure extremely low speeds in only one second of measurement time," explains Bortolozzo. He says a next step will be for the team to test their dye and liquid crystal slow light approach in similar phase sensing applications. The team will also endeavor to extend the work to other molecular arrangements and different types of dye. "Realizing slow and stopped light in these media is very exciting both for the fundamental research that discovers such new effects in soft matter systems, and for the new possibilities that these investigations could open in the fields of remote sensing and optical storage," says Bortolozzo. Papers:

Tsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. Its October 30, 1961 test remains the most powerful artificial explosion in human history. It was also referred to as Kuz'kina Mat' ,referring to Nikita Khrushchev's promise to show the United States a "Kuz'kina Mat'" at the 1960 United Nations General Assembly.

The famous Russian idiom, which has been problematic for translators, literally meaning “to show somebody Kuzka's mother”, equates roughly with the English “We’ll show you!” Developed by the Soviet Union, the bomb had the yield of 50 to 58 megatons of TNT (210 to 240 PJ). Only one bomb of this type was ever officially built and it was tested on October 30, 1961, in the Novaya Zemlya archipelago, atSukhoy Nos.

The remaining bomb casings are located at the Russian Atomic Weapon Museum, Sarov (Arzamas-16), and the Museum of Nuclear Weapons, All-Russian Research Institute of Technical Physics, Snezhinsk (Chelyabinsk-70). Neither of these casings has the same antenna configuration as the device that was tested.

Many names are attributed to the Tsar Bomba in the literature: Project 7000; product code 202 ;article designations RDS-220 , RDS-202, RN202 (PH202), AN602 (AH602); codename Vanya; nicknames Big Ivan, Tsar Bomba, Kuz'kina Mat'.

 The term "Tsar Bomba" was coined in an analogy with two other massive Russian objects: the Tsar Kolokol (Tsar Bell) and the Tsar Pushka (Tsar Cannon). The CIA denoted the test as "JOE 111".

Researchers at the University of Rochester have measured for the first time light emitted by photoluminescence from a nano diamond levitating in free space. In a paper published this week in Optics Letters, they describe how they used a laser to trap nano diamonds in space, and -- using another laser -- caused the diamonds to emit light at given frequencies.

The experiment, led by Nick Vamivakas, an assistant professor of optics, demonstrates that it is possible to levitate diamonds as small as 100 nanometers (approximately one-thousandth the diameter of a human hair) in free space, by using a technique known as laser trapping.

"Now that we have shown we can levitate nanodiamonds and measure photoluminescence from defects inside the diamonds, we can start considering systems that could have applications in the field of quantum information and computing," said Vamivakas. He said an example of such a system would be an optomechanical resonator.

Vamivakas explained that optomechanical resonators are structures in which the vibrations of the system, in this case the trapped nanodiamond, can be controlled by light. "We are yet to explore this, but in theory we could encode information in the vibrations of the diamonds and extract it using the light they emit."

Possible avenues of interest in the long-term with these nano-optomechanical resonators include the creation of what are known as Schrödinger Cat states (macroscopic, or large-scale, systems that are in two quantum states at once). These resonators could also be used as extremely sensitive sensors of forces -- for example, to measure tiny displacements in the positions of metal plates or mirrors in configurations used in microchips and understand friction better on the nanoscale.

"Levitating particles such as these could have advantages over other optomechanical oscillators that exist, as they are not attached to any large structures," Vamivakas explained. "This would mean they are easier to keep cool and it is expected that fragile quantum coherence, essential for these systems to work, will last sufficiently long for experiments to be performed."

The future experiments that Vamivakas and his team are planning build on previous work at Rochester by Lukas Novotny, a co-author of the paper and now at ETH in Zurich, Switzerland. Novotny and his group showed previously that by tweaking the trapping laser's properties, a particle can be pushed towards its quantum ground state. By linking the laser cooling of the crystal resonator with the spin of the internal defect it should be possible to monitor the changes in spin configuration of the internal defect -- these changes are called Bohr spin quantum jumps -- via the mechanical resonator's vibrations. Vamivakas explained that experiments like this would expand what we know about the classical-quantum boundary and address fundamental physics questions.

The light emitted by the nanodiamonds is due to photoluminescence. The defects inside the nanodiamonds absorb photons from the second laser -- not the one that is trapping the diamonds -- which excites the system and changes the spin. The system then relaxes and other photons are emitted. This process is also known as optical pumping.

The defects come about because of nitrogen vacancies, which occur when one or more of the carbon atoms in diamond is replaced by a nitrogen atom. The chemical structure is such that at the nitrogen site it is possible to excite electrons, using a laser, between different available energy levels. Previous experiments have shown that these nitrogen vacancy centers in diamonds are good, stable sources of single photons, which is why the researchers were keen to levitate these particles.

Using lasers to trap ions, atoms and more recently larger particles is a well-established field of physics. Nanodiamonds, however, had never been levitated. To position these 100 nanometers diamonds in the correct spot an aerosol containing dissolved nanodiamonds sprays into a chamber about 10 inches in diameter, where the laser's focus point is located. The diamonds are attracted to this focus point and when they drift into this spot they are trapped by the laser. Graduate student Levi Neukirch explains that sometimes "it takes a couple of squirts and in a few minutes we have a trapped nanodiamond; other times I can be here for half an hour before any diamond gets caught. Once a diamond wanders into the trap we can hold it for hours."

The Rochester researchers collaborated on this paper with Lukas Novotny, formerly at the University of Rochester and now at ETH Zurich, Switzerland, and with Jan Gieseler and Romain Quidant, at ICFO in Barcelona, Spain.

The researchers acknowledge the support from the University of Rochester, the European Community's Seventh Framework Program, Fundació privada CELLEX and from the U.S. Department of Energy.

India on Saturday took a major leap towards completing its nuclear triad – the ability to launch strategic weapons from land, air and sea with the miniature reactor on board the country’s first indigenous nuclear-powered submarine “attaining criticality”. It means the reactor is in stable configuration producing constant power.

The 6,000 tonne Arihant, which means destroyer of enemies, will head for sea trials later this year. The submarine will kick off deterrent patrols, armed with nuclear warheads, in early 2014.The submarine will complete the sea-leg of India’s nuclear triad, giving it enduring nuclear strike and counter-strike capabilities.
It will be equipped with the K-15 missile, a closely guarded DRDO secret, capable of delivering a nuclear warhead up to 750 km away.

India already has the capability to carry out nuclear strikes with fighter planes and land-launched missiles. The Agni series of ballistic missiles and fighters planes such as Sukhoi-30MKIs and French-origin Mirage-2000s can deliver nuclear warheads. The Rafale fighters being acquired from France are also nuclear capable.India has 90-110 nuclear warheads, compared to 250 in the Chinese arsenal.

The United States, Russia, the UK, France and China are the only countries that can deliver nuclear warheads from a submarine.Experts say India’s submarine fleet should have at least 5 nuclear-powered ballistic missile submarines.Two more nuclear-powered submarines are in the works to reinforce India’s strategic deterrent force at sea.The INS Chakra, leased from Russia in January 2012, cannot deliver nuclear warheads in its current configuration. It only carries torpedoes, land-attack cruise missiles and anti-ship missiles.

A Maya pyramid beautifully decorated with a rare polychrome-painted stucco frieze was unearthed in July 2013 at the site of Holmul, a Classic Maya city in northeastern Peten region of Guatemala. The find came as archaeologist Francisco Estrada-Belli's team excavated in a tunnel left open by looters. The stucco relief stands along the exterior of a multi-roomed rectangular building, measuring 8m in length and 2m in height. Much of the building still remains encased under the rubble of a later 20m-high structure. The carving is painted in red, with details in blue, green and yellow.

"This is a unique find. It is a beautiful work of art and it tells us so much about the function and meaning of the building, which was what we were looking for," says Estrada-Belli. The carving depicts human figures in a mythological setting, suggesting these may be deified rulers. The team had hoped to find clues to the function of this building, since the unearthing of an undisturbed tomb last year. The burial contained an individual accompanied by 28 ceramic vessels and a wooden funerary mask.

An inscription below the figures tells us that this edifice was commissioned by the ruler of Naranjo, a powerful kingdom to the south of Holmul. In the dedication, king "Ajwosaj Chan K'inich" claims to have restored the local ruling line and patron deities. The images and glyphic text on the frieze also provide information about political actors in the Maya Lowlands well beyond this small kingdom. "One of the glyphs describes Ajwosaj as 'vassal of the Kanul king,' suggesting a much wider network of influences was being felt at Holmul. When this building was erected, Kanul kings were already on their way to controlling much of the lowlands, except Tikal of course," added Estrada-Belli.

The text places the building in the decade of the 590s, according to Alex Tokovinine, a Harvard University Maya epigrapher associated with the project. who has deciphered the text. "Ajwosaj was one of the greatest rulers of Naranjo. The new inscription provides the first glimpse of the remarkable extent of Ajwosaj's political and religious authority. It also reveals how a new order was literally imprinted on a broader landscape of local gods and ancestors," says Tokovinine.

During the Early Classic period (A. D. 300-550) the Tikal kings had established new dynasties and far-reaching alliances with kingdoms throughout the Maya Lowlands, perhaps thanks to a connection with Mesoamerica's greatest state, Teotihuacan. Tikal suffered a defeat in the year 562 by the Kanul "Snake" kingdom, which, for the following 180 years, would come to dominate most other Lowland kingdoms. An inscription at Naranjo indicates that Kanul king K'altuun Hix had overseen the accession of Ajwosaj, as early as the year 545.

The relief depicts three human figures wearing elaborate bird headdresses and jade jewels seated cross-legged over the head of a mountain spirit known as a witz ("mountain"). A cartouche on the headdress contains glyphs identifying each individual by name. The central figure's name is the only readable one: OchChan Yopaat, meaning "The Storm God enters the sky. " Two feathered serpents emerge from the mountain spirit below the main character and form an arch with their bodies. Under each of them is a seated figure of an aged god holding a sign that reads "First tamale. " In front of the serpents' mouths are the two additional human figures, also seated on mountain spirit heads.

A band of about 30 incised glyphs adorns the bottom of the frieze. The legible parts mention the actions of Naranjo king Ajwosaj, who put the king's house in order," put Och Chan Yopaat (the central figure in the frieze) in order, and put several local patron gods in order.

The tomb associated with the building was found in a cavity dug into the stairway leading up to the building. The skeleton of an adult male and his ceramic offering were preserved by large limestone slabs that kept the tomb free of debris. His incisor and canine teeth has been drilled and filled with jade beads. The decayed remains of a wooden mask, perhaps originally worn as a pectoral, were found on his chest. With it were two miniature flower-shaped ear spools.

The number of vessels in the tomb as well as their iconography bore clear references to the nine lords of the underworld as well as to the aged sun god of the underworld. There were two sets of nine polychrome-painted bowls decorated with the water lily motif, each made by a different artist. There were also nine red-painted plates and one spouted tripod plate decorated with the image of the god of the underworld emerging from a shell. Because of the unusually high number of vessels and the jade dental decorations, Estrada-Belli believes this individual may have been a member of the ruling class at Holmul; he had planned this year's excavation to search for more clues about the man and the period in which he had lived.

The team hopes to return to the area in 2014 to continue exploring and to preserve this building. This year's investigation was endorsed by Guatemala's Ministry of Culture with funding from Guatemala's PACUNAM foundation and the U. S. -based Alphawood Foundation with additional support from Boston University, National Geographic Society/Waitt Grants Program, and private donors.

Francisco Estrada-Belli

Francisco Estrada-Belli is an Italian-Guatemalan archaeologist affiliated with Boston University and the American Museum of Natural History, who is currently teaching at Tulane University. He received a Ph. D. degree from Boston University in 1998. Since 2000 he has directed the Holmul Archaeological Project, a multi-disciplinary investigation of early Maya culture in Guatemala. He is author of numerous scholarly articles on the Maya including the recent book "The First Maya Civilization. Ritual and Power before the Classic period. "He is a National Geographic explorer, having received 13 research grants from the National Geographic Society, and a Fellow of the Society of Antiquaries of London. He is co-founder of the Maya Archaeology Initiative, a nonprofit for heritage preservation and education in the Maya Biosphere of Guatemala.

For more information, see National Geographic's news story at:

http://news.nationalgeographic.com/news/2013/08/pictures/130807-maya-frieze-discovered-holmul-guatemala-archaeology
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