CERN’s Large Hadron Collider Experiments Bring New Insight Into Matter of the Primordial Universe

Experiments using heavy ions at CERN's Large Hadron Collider (LHC) are advancing understanding of the primordial Universe. 

The ALICE, ATLAS and CMS collaborations have made new measurements of the kind of matter that probably existed in the first instants of the Universe. They will present their latest results at the 2012 Quark Matter conference, which starts August 13 in Washington DC. The new findings are based mainly on the four-week LHC run with lead ions in 2011, during which the experiments collected 20 times more data than in 2010.

Just after the Big Bang, quarks and gluons -- basic building blocks of matter -- were not confined inside composite particles such as protons and neutrons, as they are today. Instead, they moved freely in a state of matter known as 'quark-gluon plasma'. Collisions of lead ions in the LHC, the world's most powerful particle accelerator, recreate for a fleeting moment conditions similar to those of the early Universe. By examining a billion or so of these collisions, the experiments have been able to make more precise measurements of the properties of matter under these extreme conditions.

"The field of heavy-ion physics is crucial for probing the properties of matter in the primordial Universe, one of the key questions of fundamental physics that the LHC and its experiments are designed to address. It illustrates how in addition to the investigation of the recently discovered Higgs-like boson, physicists at the LHC are studying many other important phenomena in both proton-proton and lead-lead collisions," said CERN Director General Rolf Heuer.

At the conference, the ALICE, ATLAS and CMS collaborations will present more refined characterizations of the densest and hottest matter ever studied in the laboratory -- 100,000 times hotter than the interior of the Sun and denser than a neutron star.

ALICE will present a wealth of new results on all aspects of the evolution in both space and time of high-density strongly interacting matter. Important studies deal with "charmed particles," which contain a charm or anti-charm quark. Charm quarks, 100 times heavier than the up and down quarks that form normal matter, are significantly decelerated by their passage through quark-gluon plasma, offering scientists a unique tool to probe its properties. ALICE physicists will report indications that the flow in the plasma is so strong that the heavy charmed particles are dragged along by it. The experiment has also observed indications of a thermalization phenomenon, which involves the recombination of charm and anti-charm quarks to form "charmonium."

"This is only one leading example of the scientific opportunities in reach of the ALICE experiment," said Paolo Giubellino, spokesperson of the ALICE collaboration. "With more data still being analysed and further data-taking scheduled for next February, we are closer than ever to unravelling the properties of the primordial state of the Universe: the quark-gluon plasma."

In the 1980s, the initial dissociation of charmonium was proposed as a direct signature for the formation of quark-gluon plasma, and first experimental indications of this dissociation were reported from fixed-target experiments at CERN's Super Proton Synchrotron in 2000. The much higher energy of the LHC makes it possible for the first time to study similar tightly-bound states of the heavier beauty quarks. The hypothesis was that, depending on their binding energy, some of these states would "melt" in the plasma produced, while others would survive the extreme temperature. The CMS experiment now observes clear signs of the expected sequential suppression of the "quarkonium" (quark-antiquark) states.

"CMS will present important new heavy-ion results not only on quarkonium suppression, but also on bulk properties of the medium and on a variety of studies of jet quenching," said Joseph Incandela, the CMS Spokesperson. "We are entering an exciting new era of high-precision research on strongly interacting matter at the highest energies produced in the laboratory."

The quenching of jets is the phenomenon in which highly energetic sprays of particles break up in the dense quark-gluon plasma, giving scientists detailed information about the density and properties of the produced matter. ATLAS will report new findings on jet quenching, including a high-precision study of how the jets fragment in matter, and on the correlations between jets and electroweak bosons. The results are complementary to other exciting ones, including groundbreaking findings on the flow of the plasma.

"We have entered a new phase in which we not only observe the phenomenon of quark-gluon plasma, but where we can also make high-precision measurements using a variety of probes," said Fabiola Gianotti, the ATLAS spokesperson. "The studies will contribute significantly to our understanding of the early Universe."

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New Bacteria-Resistant Materials Discovered

Using state-of-the-art technology, scientists at The University of Nottingham have discovered a new class of polymers that are resistant to bacterial attachment. These new materials could lead to a significant reduction in hospital infections and medical device failures.

Medical device associated infections can lead to systemic infections or device failure, costing the NHS £1bn a year. Affecting many commonly used devices including urinary and venous catheters -- bacteria form communities known as biofilms. This 'strength in numbers approach' protects them against the bodies' natural defences and antibiotics.

Experts in the Schools of Pharmacy and Molecular Medical Sciences, have shown that when the new materials are applied to the surface of medical devices they repel bacteria and prevent them forming biofilms.

The research was led by Professor Morgan Alexander, and Professor Martyn Davies in the School of Pharmacy and Professor Paul Williams in the School of Molecular Medical Sciences. 

The novel materials had to be found using a new technique

Researchers believed there were new materials that could resist bacteria better but they had to find them. This meant screening thousands of different chemistries and testing their reaction to bacteria -- a challenge which was beyond conventional materials development or any of our current understanding of the interaction of micro-organisms with surfaces.

The discovery has been made with the help of experts from the Massachusetts Institute of Technology (MIT) -- who initially developed the process by which thousands of unique polymers can now be screened simultaneously.

Professor Alexander said: "This is a major scientific breakthrough -- we have discovered a new group of structurally related materials that dramatically reduce the attachment of pathogenic bacteria (Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli). We could not have found these materials using the current understanding of bacteria-surface interactions. The technology developed with the help of MIT means that hundreds of materials could be screened simultaneously to reveal new structure-property relationships. In total thousands of materials were investigated using this high throughput materials discovery approach leading to the identification of novel materials resisting bacterial attachment. This could not have been achieved using conventional techniques."

These new materials prevent infection by stopping biofilm formation at the earliest possible stage -- when the bacteria first attempt to attach themselves to the device. In the laboratory experts were able to reduce the numbers of bacteria by up to 96.7per cent -- compared with a commercially available silver containing catheter -- and were effective at resisting bacterial attachment in a mouse implant infection model. By preventing bacterial attachment the body's own immune system can kill the bacteria before they have time to generate biofilms.

Ted Bianco, Director of Technology Transfer at the Wellcome Trust, said: "Infections caused by microbial biofilms binding to the surface of implants often cannot be treated with conventional antibiotics. This makes them a significant challenge in patient care, particularly for those with inserted medical devices like catheters, heart valves and prosthetic joints. The discovery of these new polymers is a great example of how advances in materials science are being exploited in our efforts to improve the performance of critical medical components. Just as materials science gave us the non-stick saucepan, so we look forward to the day of the 'non-stick' medical device."

Bacterial attachment and subsequent biofilm formation are key challenges to the performance of medical devices. This is early stage research but the initial results are very promising. The next stage of this research will be to develop the manufacture of these coatings to enable the performance of these materials to be assessed clinically and the inventors are in early stage discussions with a number of medical device companies.

The results of the £1.3m four year research project supported by a Translation Award from the Wellcome Trust, have been published on August 12, 2012, in the academic journal Nature Biotechnology.

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Spintronics in Computing are Near

Aiming to use electron spins for storing, transporting and processing information, researchers from IBM and scientists at ETH Zurich, a leading European university, have revealed the first-ever direct mapping of the formation of a persistent spin helix in a semiconductor.

Until now, it was unclear whether or not electron spins possessed the capability to preserve the encoded information long enough before rotating. Unveiled in the peer-reviewed journal Nature Physics, scientists from IBM Research and the Solid State Physics Laboratory at ETH Zurich demonstrated that synchronizing electrons extends the spin lifetime of the electron by 30 times to 1.1 nanoseconds -- the same time it takes for an existing 1 GHz processor to cycle.

Today's computing technology encodes and processes data by the electrical charge of electrons. However, this technique is limited as the semiconductor dimensions continue to shrink to the point where the flow of electrons can no longer be controlled. Spintronics could surmount this approaching impasse by harnessing the spin of electrons instead of their charge.

This new understanding in spintronics not only gives scientists unprecedented control over the magnetic movements inside devices but also opens new possibilities for creating more energy efficient electronics.

The Spintronics Waltz

A previously unknown aspect of physics, the scientists observed how electron spins move tens of micrometers in a semiconductor with their orientations synchronously rotating along the path similar to a couple dancing the waltz, the famous Viennese ballroom dance where couples rotate.

Dr. Gian Salis of the Physics of Nanoscale Systems research group at IBM Research -- Zurich explains, "If all couples start with the women facing north, after a while the rotating pairs are oriented in different directions. We can now lock the rotation speed of the dancers to the direction they move. This results in a perfect choreography where all the women in a certain area face the same direction. This control and ability to manipulate and observe the spin is an important step in the development of spin-based transistors that are electrically programmable."

How it Works

IBM scientists used ultra short laser pulses to monitor the evolution of thousands of electron spins that were created simultaneously in a very small spot. Atypically, where such spins would randomly rotate and quickly loose their orientation, for the first time, the scientists could observe how these spins arrange neatly into a regular stripe-like pattern, the so-called persistent spin helix.

The concept of locking the spin rotation was originally proposed in theory back in 2003 and since that time some experiments have even found indications of such locking, but until now it had never been directly observed.

IBM scientists imaged the synchronous 'waltz' of the electron spins by using a time-resolved scanning microscope technique. The synchronization of the electron spin rotation made it possible to observe the spins travel for more than 10 micrometers or one-hundredth of a millimeter, increasing the possibility to use the spin for processing logical operations, both fast and energy-efficiently.

The reason for the synchronous spin motion is a carefully engineered spin-orbit interaction, a physical mechanism that couples the spin with the motion of the electron. The semiconductor material called gallium arsenide (GaAs) was produced by scientists at ETH Zurich who are known as world-experts in growing ultra-clean and atomically precise semiconductor structures. GaAs is a III/V semiconductor commonly used in the manufacture of devices such as integrated circuits, infrared light-emitting diodes and highly efficient solar cells.

Transferring spin electronics from the laboratory to the market still remains a major challenge. Spintronics research takes place at very low temperatures at which electron spins interact minimally with the environment. In the case of this particular research IBM scientists worked at 40 Kelvin (-233 C, -387 F).

This work was financially supported by the Swiss National Science Foundation through National Center of Competence in Research (NCCR) Nanoscale Sciences and NCCR Quantum Science and Technology.

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Urban Sun Corridor 4 Degrees Warmer?

According to the United Nations' 2011 Revision of World Urbanization Prospects, global urban population is expected to gain more than 2.5 billion new inhabitants through 2050.

Such sharp increases in the number of urban dwellers will require considerable conversion of natural to urban landscapes, resulting in newly developing and expanding megapolitan areas. Could climate impacts arising from built environment growth pose additional concerns for urban residents also expected to deal with impacts resulting from global climate change?

In the first study to attempt to quantify the impact of rapidly expanding megapolitan areas on regional climate, a team of researchers from Arizona State University (ASU) and the National Center for Atmospheric Research has established that local maximum summertime warming resulting from projected expansion of the urban Sun Corridor could approach 4 degrees Celsius. This finding establishes that this factor can be as important as warming due to increased levels of greenhouse gases. Their results are reported in the early online edition (Aug. 12) of the journal Nature Climate Change.

Arizona's Sun Corridor is the most rapidly growing megapolitan area in the United States. Nestled in a semi-arid environment, it is composed of four metropolitan areas: Phoenix, Tucson, Prescott and Nogales. With a population projection expected to exceed 9 million people by 2040, the developing Sun Corridor megapolitan provides a unique opportunity to diagnose the influence of large-scale urbanization on climate, and its relation to global climate change.

"We posed a fundamental set of questions in our study, examining the different scenarios of Sun Corridor expansion through mid-century. We asked what are the summertime regional climate implications, and how do these impacts compare to climate change resulting from increased emissions of greenhouse gases," says Matei Georgescu, lead author and assistant professor in the School of Geographical Sciences and Urban Planning in ASU's College of Liberal Arts and Sciences.

The authors utilized projections of Sun Corridor growth by 2050 developed by the Maricopa Association of Governments (MAG), the regional agency for metropolitan Phoenix provides long-range and sustainably oriented planning. Incorporating maximum and minimum growth scenarios into a state-of-the-art regional climate model, the researchers compared these impacts with experiments using an urban representation of modern-day central Arizona. Their conclusions indicate substantial summertime warming.

"The worst case expansion scenario we utilized led to local maximum summer warming of nearly 4 degrees Celsius. In the best case scenario, where Sun Corridor expansion is both more constrained and urban land use density is lower, our results still indicate considerable local warming, up to about 2 degrees Celsius," Georgescu said.

An additional experiment was conducted to examine an adaptation where all of the buildings were topped by highly reflective white or "cool" roofs.

"Incorporating cool roofs alleviated summertime warming substantially, reducing the maximum local warming by about half," Georgescu said. "But, another consequence of such large-scale urbanization and this adaptation approach include effects on the region's hydroclimate."

The cool roofs, like the maximum-growth scenario without this adaptation approach, further reduce evapotranspiration -- water that evaporates from the soil and transpires from plants. Ultimately, comparison of summertime warming resulting from Sun Corridor expansion to greenhouse-gas-induced summertime climate change shows that through mid-century the maximum urbanization scenario leads to greater warming than climate change.

However, pinning precise figures on the relative contribution of each effector is difficult, the authors state.

"The actual contribution of urban warming relative to summertime climate change warming depends critically on the path of urbanization, the conversion of natural to urban landscapes, and the degree to which we continue to emit greenhouse gases," said Alex Mahalov, a co-author and principal investigator of the National Science Foundation grant, "Multiscale Modeling of Urban Atmospheres in a Changing Climate," which supported the research.

"As well as providing insights for sustainable growth of the Sun Corridor and other rapidly expanding megapolitan areas, this research offers one way to quantify and understand the relative impacts of urbanization and global warming,"said Mahalov, the Wilhoit Foundation Dean's Distinguished Professor in ASU's School of Mathematical and Statistical Sciences.

The group conducted their numerical simulations using an "ensemble-based" approach. By modifying their model's initial conditions and repeating their simulations a number of times, they were able to test the robustness of their results. In all, nearly half of a century of simulations were conducted.

"By incorporating differing Sun Corridor growth scenarios into a high performance computing modeling framework with MAG projections, we quantified direct hydroclimatic impacts due to anticipated expansion of the built environment," added Mahalov. Simulations were conducted at ASU's Advanced Computing Center (A2C2).

Georgescu said that one take-home message from this study is that the incorporation of sustainable policies need to extend beyond just greenhouse gas emissions. He also stressed the importance of extending adaptation strategies beyond the focus on mere average temperature.

"Truly sustainable adaptation, from an environmental standpoint, must extend to the entire climate system, including impacts on temperature and hydrology," he said.

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Full Color Images at 100,000 Dots-Per-Inch Resolution, Using Metal-Laced Nano-Structures

Researchers from A*STAR's Institute of Materials Research and Engineering (IMRE) have developed an innovative method for creating sharp, full-spectrum colour images at 100,000 dots per inch (dpi), using metal-laced nanometer-sized structures, without the need for inks or dyes. In comparison, current industrial printers such as inkjet and laserjet printers can only achieve up to 10,000 dpi while research grade methods are able to dispense dyes for only single colour images.

This novel breakthrough allows colouring to be treated not as an inking matter but as a lithographic matter, which can potentially revolutionise the way images are printed and be further developed for use in high-resolution reflective colour displays as well as high density optical data storage.

The inspiration for the research was derived from stained glass, which is traditionally made by mixing tiny fragments of metal into the glass. It was found that nanoparticles from these metal fragments scattered light passing through the glass to give stained glass its colours. Using a similar concept with the help of modern nanotechnology tools, the researchers precisely patterned metal nanostructures, and designed the surface to reflect the light to achieve the colour images.

"The resolution of printed colour images very much depends on the size and spacing between individual 'nanodots' of colour," explained Dr Karthik Kumar, one of the key researchers involved. "The closer the dots are together and because of their small size, the higher the resolution of the image. With the ability to accurately position these extremely small colour dots, we were able to demonstrate the highest theoretical print colour resolution of 100,000 dpi."

"Instead of using different dyes for different colours, we encoded colour information into the size and position of tiny metal disks. These disks then interacted with light through the phenomenon of plasmon resonances," said Dr Joel Yang, the project leader of the research. "The team built a database of colour that corresponded to a specific nanostructure pattern, size and spacing. These nanostructures were then positioned accordingly. Similar to a child's 'colouring-by-numbers' image, the sizes and positions of these nanostructures defined the 'numbers'. But instead of sequentially colouring each area with a different ink, an ultrathin and uniform metal film was deposited across the entire image causing the 'encoded' colours to appear all at once, almost like magic!" added Dr Joel Yang.

The researchers from IMRE had also collaborated with A*STAR's Institute of High Performance Computing (IHPC) to design the pattern using computer simulation and modelling. Dr Ravi Hegde of IHPC said, "The computer simulations were vital in understanding how the structures gave rise to such rich colours. This knowledge is currently being used to predict the behaviour of more complicated nanostructure arrays."

The researchers are currently working with Exploit Technologies Pte Ltd (ETPL), A*STAR's technology transfer arm, to engage potential collaborators and to explore licensing the technology. The research was published online on August 12, 2012 in Nature Nanotechnology.

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Scientists Use Light to 'Tag and Track' Genetic Processes

In a new study, UT Dallas researchers outline how they used fluorescent molecules to "tag" DNA and monitor a process called DNA looping, a natural biological mechanism involved in rearranging genetic material in some types of cells.

The UT Dallas "tag and track" method not only sheds light on how DNA loops form, but also might be adapted to screen drugs for effectiveness against certain viruses that shuffle genetic material, such as HIV.

Until now, scientists primarily had "snapshots" of the initial and final stages of DNA loop formation, with only limited information about what happens during the intermediate steps, said Dr. Stephen Levene, professor of bioengineering, molecular and cell biology, and phyiscs at UT Dallas. He is senior author of the study, published online and in an upcoming issue of the journal Nucleic Acids Research.

"Scientists have known for more than 30 years that DNA looping is an important part of molecular biology and gene regulation, but until our work, there have been few serious attempts to understand the basic biophysics of the process," Levene said.

DNA looping is a mechanism common in many instances of natural gene-splicing. Proteins within cells -- or proteins made by invading viruses -- latch onto specific docking points on a DNA molecule. They bring those points together to form a loop, and then snip out the genetic material between the points while reconnecting the now-loose ends.

DNA loop formation is especially important in organisms whose genetic material is circular, including some bacteria and viruses. Human DNA is linear, but the possibility that DNA looping takes place in human cells is an ongoing area of investigation, Levene said.

Levene and UT Dallas doctoral student Massa Shoura, the lead author of the paper, used a protein called Cre in their experiments. Cre is made by a virus that infects bacteria and is so good at forming DNA loops and excising genetic material that scientists routinely use it to delete genes from laboratory animals, which are then used to study the role of genes in human disease.

Levene and Shoura engineered isolated segments of DNA to contain Cre's docking points. They also inserted into those points a molecule that fluoresces when exposed to certain wavelengths of light. By monitoring the changes in fluorescence, the researchers could watch the steps of the loop formation.

The information the researchers have gleaned is not only useful for understanding basic biology and genetics, but also might lead to more efficient methods for screening potential new drugs for anti-HIV activity.

Once inside a host cell, HIV produces an enzyme similar to Cre, called an integrase. As its name suggests, the integrase slices into the host's DNA and inserts HIV's genetic material.

"Our fluorescent-tag technique could be used in the lab to more closely examine how HIV inserts itself into the host's genome," Shoura said. "By labeling and monitoring the process, we also could test drugs designed to interfere with the integrase."

"We estimate that using fluorescence-based methods such as this for drug screening could be as much as 10,000 times more efficient than methods that are currently used," Levene said.

Other UT Dallas researchers from the Department of Molecular and Cell Biology who participated in the study were senior scientist Dr. Alexandre Vetcher; doctoral students Stefan Giovan, Farah Bardai and Anusha Bharadwaj; and former undergraduate student Matthew Kesinger. The National Institutes of Health and the National Science Foundation funded the research.

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Scientist Discovers Plate Tectonics On Mars

For years, many scientists had thought that plate tectonics existed nowhere in our solar system but on Earth. Now, a UCLA scientist has discovered that the geological phenomenon, which involves the movement of huge crustal plates beneath a planet's surface, also exists on Mars.

"Mars is at a primitive stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth," said An Yin, a UCLA professor of Earth and space sciences and the sole author of the new research.

Yin made the discovery during his analysis of satellite images from a NASA spacecraft known as THEMIS (Time History of Events and Macroscale Interactions during Substorms) and from the HIRISE (High Resolution Imaging Science Experiment) camera on NASA's Mars Reconnaissance Orbiter. He analyzed about 100 satellite images -- approximately a dozen were revealing of plate tectonics.

Yin has conducted geologic research in the Himalayas and Tibet, where two of Earth's seven major plates divide.

"When I studied the satellite images from Mars, many of the features looked very much like fault systems I have seen in the Himalayas and Tibet, and in California as well, including the geomorphology," said Yin, a planetary geologist.

For example, he saw a very smooth, flat side of a canyon wall, which can be generated only by a fault, and a steep cliff, comparable to cliffs in California's Death Valley, which also are generated by a fault. Mars has a linear volcanic zone, which Yin said is a typical product of plate tectonics.

"You don't see these features anywhere else on other planets in our solar system, other than Earth and Mars," said Yin, whose research is featured as the cover story in the August issue of the journal Lithosphere.

The surface of Mars contains the longest and deepest system of canyons in our solar system, known as Valles Marineris (Latin for Mariner Valleys and named for the Mariner 9 Mars orbiter of 1971-72, which discovered it). It is nearly 2,500 miles long -- about nine times longer than Earth's Grand Canyon. Scientists have wondered for four decades how it formed. Was it a big crack in Mars' shell that opened up?

"In the beginning, I did not expect plate tectonics, but the more I studied it, the more I realized Mars is so different from what other scientists anticipated," Yin said. "I saw that the idea that it is just a big crack that opened up is incorrect. It is really a plate boundary, with horizontal motion. That is kind of shocking, but the evidence is quite clear.

"The shell is broken and is moving horizontally over a long distance. It is very similar to the Earth's Dead Sea fault system, which has also opened up and is moving horizontally."

The two plates divided by Mars' Valles Marineris have moved approximately 93 miles horizontally relative to each other, Yin said. California's San Andreas Fault, which is over the intersection of two plates, has moved about twice as much -- but Earth is about twice the size of Mars, so Yin said they are comparable.

Yin, whose research is partly funded by the National Science Foundation, calls the two plates on Mars the Valles Marineris North and the Valles Marineris South.

"Earth has a very broken 'egg shell,' so its surface has many plates; Mars' is slightly broken and may be on the way to becoming very broken, except its pace is very slow due to its small size and, thus, less thermal energy to drive it," Yin said. "This may be the reason Mars has fewer plates than on Earth."

Mars has landslides, and Yin said a fault is shifting the landslides, moving them from their source.

Does Yin think there are Mars-quakes?

"I think so," he said. "I think the fault is probably still active, but not every day. It wakes up every once in a while, over a very long duration -- perhaps every million years or more."

Yin is very confident in his findings, but mysteries remain, he said, including how far beneath the surface the plates are located.

"I don't quite understand why the plates are moving with such a large magnitude or what the rate of movement is; maybe Mars has a different form of plate tectonics," Yin said. "The rate is much slower than on Earth."

Earth has a broken shell with seven major plates; pieces of the shell move, and one plate may move over another. Yin is doubtful that Mars has more than two plates.

"We have been able to identify only the two plates," he said. "For the other areas on Mars, I think the chances are very, very small. I don't see any other major crack."

Did the movement of Valles Marineris North and Valles Marineris South create the enormous canyons on Mars? What led to the creation of plate tectonics on Earth?

Yin, who will continue to study plate tectonics on Mars, will answer those questions in a follow-up paper that he also plans to publish in the journal Lithosphere.

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Evidence Further Suggests Extra-Terrestrial Origin of Quasicrystals

Results from an expedition to far eastern Russia that set out to find the origin of naturally occurring quasicrystals have provided convincing evidence that they arrived on Earth from outer space.

Writing in IOP Publishing's journalReports on Progress in Physics, Paul J Steinhardt and Luca Bindi reveal that new, naturally occurring quasicrystal samples have been found in an environment that does not have the extreme terrestrial conditions needed to produce them, therefore strengthening the case that they were brought to Earth by a meteorite. Furthermore, their findings reveal that the samples of quasicrystals were brought to the area during the last glacial period, suggesting the meteorite was most likely to have hit Earth around 15 000 years ago.

"The fact that the expedition found more material in the same location that we had spent years to track down is a tremendous confirmation of the whole story, which is significant since the meteorite is of great interest because of its extraordinary age and contents," said Steinhardt.

In their report, Steinhardt and Bindi describe the expedition in which ten scientists, two drivers and a cook travelled 230 km into the Koryak Mountains of far eastern Russia to pan one and a half tons of sediment by hand, and survey local streams and mountains.

The group of researchers were on the look-out for naturally occurring quasicrystals -- a unique class of solids that were first synthesized in the laboratory by Israeli scientist Dan Shechtman in 1982. He was awarded the Nobel Prize for Chemistry in 2011 for this discovery.

The concept of quasicrystals was first introduced by Steinhardt and his student Dov Levine. Until their work, it had been believed that all solids, synthetic or natural, form ordinary crystals -- materials whose entire structure is made of a single-type cluster of atoms that repeat at regular intervals, joining together in much the same way as identical tiles in bathroom tiling.

It was also thought that crystals could only have two-, three-, four- and six-fold symmetries; however, Steinhardt and Levine found a new theoretical possibility, which they dubbed quasicrystals. A quasicrystal has two or more types of clusters that repeat at different intervals with an irrational ratio, which allows all the symmetries that were thought to be forbidden, such as five-fold symmetry, to be possible.

Since their discovery in the laboratory, researchers have created over one hundred artificial quasicrystals that have been used in a variety of applications, from non-stick frying pans and cutlery to ball bearings and razor blades.

Only one natural quasicrystal has been previously documented: a sample in the Museum of Natural History in Florence, Italy, that was located and identified by the two co-authors and their collaborators in 2009. They found the sample to have the symmetry of a soccer ball, with six axes of five-fold symmetry forbidden to ordinary crystals. This triggered a remarkable investigation to find the place where the sample came from, which, as Steinhardt states, involved secret diaries, smugglers, gold prospectors and bears.

Eventually, the researchers found the person, Valery Kryachko, who had removed the sample from a remote area of Chukotka in the Russian mountains back in 1979.

In the summer of 2010, the researchers' experiments indicated that the sample was meteoritic and had come from not just any type of meteorite, but a CV3 carbonaceous chondrite -- a 4.5 billion-year-old meteorite formed at the beginning of the solar system.

"Now there was real motivation to turn this fantasy trip into a reality. It was a long shot, but if we could find even one sample there, it would prove the bizarre story we had put together beyond any shadow of doubt and provide new sources of material for studying this very strange meteorite that formed at the beginning of the solar system," Steinhardt continued.

Now that Steinhardt, Bindi and their expedition team have collected even more samples from the original site in Chukotka, there are a number of questions that can now be answered with further investigation.

"What does nature know that we don't? How did the quasicrystal form so perfectly inside a complex meteorite when we normally have to work hard in the laboratory to get anything as perfect? What other new phases can we find in this meteorite and what can they tell us about the early solar system?

"At the moment, we are at the tip of the iceberg," said Steinhardt.

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Hubble Sees a Ten Billion Year Stellar Dance

The NASA/ESA Hubble Space Telescope offers a delightful view of the crowded stellar encampment called Messier 68, a spherical, star-filled region of space known as a globular cluster. Mutual gravitational attraction amongst a cluster's hundreds of thousands or even millions of stars keeps stellar members in check, allowing globular clusters to hang together for many billions of years.

Astronomers can measure the ages of globular clusters by looking at the light of their constituent stars. The chemical elements leave signatures in this light, and the starlight reveals that globular clusters' stars typically contain fewer heavy elements, such as carbon, oxygen and iron, than stars like the Sun. Since successive generations of stars gradually create these elements through nuclear fusion, stars having fewer of them are relics of earlier epochs in the Universe. Indeed, the stars in globular clusters rank among the oldest on record, dating back more than 10 billion years.

More than 150 of these objects surround our Milky Way galaxy. On a galactic scale, globular clusters are indeed not all that big. In Messier 68's case, its constituent stars span a volume of space with a diameter of little more than a hundred light-years. The disc of the Milky Way, on the other hand, extends over some 100,000 light-years or more.

Messier 68 is located about 33,000 light-years from Earth in the constellation Hydra (the female water snake). French astronomer Charles Messier notched the object as the sixty-eighth entry in his famous catalogue in 1780.

Hubble added Messier 68 to its own impressive list of cosmic targets in this image using the Wide Field Camera of Hubble's Advanced Camera for Surveys. The image, which combines visible and infrared light, has a field of view of approximately 3.4 by 3.4 arcminutes.

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Two Separate Extinctions Brought End to Dinosaur Era

The mass extinction that wiped out the dinosaurs 65 million years ago was almost unprecedented in its size. There may be a simple reason why three-quarters of Earth's species disappeared during the event – there were actually two extinctions at the end of the Cretaceous, each devastating species in distinct environments.

Famously, the dinosaurs met their end when a massive meteorite crashed into Mexico's Yucatán Peninsula around 65 million years ago. The extinction paved the way for the rapid evolutionary diversification of mammals.

But sceptics have long questioned whether the meteorite was solely responsible for the extinction. They point out that there were massive volcanic eruptions in India more than 100,000 years earlier, which triggered global warming that might have contributed to the species fatalities. But convincing evidence for those claims has proved elusive, so the impact has taken most of the blame.

A key problem has been finding sedimentary rocks that were formed at exactly the right time to capture all of the events that might have contributed to the extinction. The rocks need to contain plenty of fossils too, to reveal exactly when the various species disappeared.

Thomas Tobin at the University of Washington in Seattle has just found rocks that fit the bill on Seymour Island, just off the Antarctic Peninsula. "It is really far south, so any climate changes are likely to be strongest there and have more biological effects," he says.

Tobin found two layers in the rocks, which formed in a shallow sea, where several species of shelled animals went extinct. One of the layers dates to the time of the impact, but the other layer is 40 metres below. Dating showed that the lower extinction occurred some 150,000 years before the meteorite hit – at the peak of the Indian eruptions. Tobin's team looked at isotopic ratios in the rock to work out the temperatures at the time: the first extinction followed a 7 °C rise in polar ocean temperatures – probably a result of global warming triggered by the Indian volcanism.

Comparable numbers of species in the region went extinct in each event. Surprisingly, though, the types of animals affected differed strikingly.

"The stuff living at the [ocean] bottom died out during the [volcanic extinction event]," says Peter Ward, Tobin's thesis advisor and collaborator. That might be because the global warming triggered by the volcanic eruptions initially increased levels of biological activity in the oceans, but ultimately used up the oxygen dissolved in the water to create lethal anoxic conditions in deep water.

The later extinction, which is linked to the meteorite impact, wiped out creatures that lived in the surface waters.

The new data suggesting two distinct extinctions ties in with results of another new study. Gerta Keller of Princeton University and her team studied microfossils from the Bay of Bengal that lived during the end of the Cretaceous. The sea floor sediments in which they are preserved is interleaved with basalt from the massive Indian lava flows. Around half of the species went extinct during the initial volcanic eruptions, long before the meteorite impact. Here, however, it was the surface-dwelling organisms that were affected by the volcanism.

The case for multiple factors contributing to the extinction is adding up, saysDavid Archibald, a vertebrate palaeontologist recently retired from San Diego State University, California, who was not involved in either study. "I'm not suggesting the [meteorite] impact didn't have tremendous effects, and it probably was necessary for the extinctions, but there were other things leading up to it," he says.

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Japan Could Become Second Biggest Solar Power Nation

WITH nuclear power on the ropes in Japan, it could be solar power's time to shine. Minamisoma City in Fukushima prefecture has signed an agreement with Toshiba to build the country's biggest solar park.

The deal comes weeks after Japan introduced feed-in tariffs to subsidise renewable energy - a move that could see the nation become one of the world's largest markets for solar power.

Parts of Minamisoma are around 10 kilometres from the Fukushima Daiichi nuclear power plant, and land there has been contaminated by radiation fallout. "Moving away from a dependency on nuclear is of course involved [with the agreement to build the solar park]," a city official said.

Both Minamisoma and neighbouring Namie have called for the cancellation of plans to build a nearby nuclear power plant - although Minamisoma has received $6.4 million over the past 25 years for initially agreeing to host the facility.

A number of Japanese municipalities have started solar projects in recent months. Plans have been drawn up for large-scale solar parks in Hokkaido and Kyushu, while SB Energy began operating two megasolar facilities, in Kyoto and Gunma, on 1 July.

"New solar projects are being generated day by day," says Toshiba's Yuji Shimada.

Solar, wind, biomass and geothermal energy still account for just 1 per cent of Japan's power capacity, however, so Japan has introduced a tariff to encourage investment. Utilities will pay solar energy firms around $0.5 per kilowatt-hour - triple the standard industrial electricity price. The extra money will come through a rise in electricity prices.

Some estimates suggest the move could help Japan leapfrog Italy andbecome the second-biggest market for solar power after Germany - although business groups fear that Japan's economic recovery will slow as a result of the electricity price rise.

Meanwhile, Japan's nuclear power industry will continue to provide competition. A reactor at the Oi nuclear facility in Fukui prefecture was brought back online as the tariffs were introduced.

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Z, The Diamond-Melting Machine with Lightning Veins

PRESSURE that can melt diamond, an electromagnetic pulse that can kill, and enough current to light 100 million light bulbs. 

Such are the extremes within the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. In this image, artificial lightning spread like a wave through Z's 33-metre-wide interior.

Designed to research nuclear fusion, Z can also help explore the behaviour of materials at ultra-high pressures and temperatures, and act as a source of intense X-rays. These abilities spring from the machine's massive pulses of current.

First the current is fired at hundreds of tiny tungsten wires, vaporising them to form a cloud of charged particles, or plasma. The plasma produces a magnetic field that forces the particles to line up at the centre of the machine, so that they point out of the horizontal plane of its surface, along the vertical or z-axis - hence the machine's name. This arrangement causes the particles to collide, producing exceptionally powerful X-rays.

Z's magnetic field can also be harnessed to accelerate metal plates and squish materials. In fact, Sandia researcher Marcus Knudson was able to apply over 5 million times atmospheric pressure to squeeze diamond, turning the precious stone into a puddle.

The magnetic field is invisible, of course. Shown here is lightning that sparks out of metal protrusions inside Z when the current is switched on. Blink and you'll miss it: this image was taken within a split second of the machine's firing.

If you are thinking about visiting Sandia to see the light show in person, you are out of luck. The top of the machine is now almost completely covered with instruments.

In any case, Z is dangerous. "There is a huge electromagnetic pulse produced that would likely kill anyone that was trying to observe a firing of the accelerator," says Knudson. "So I have only seen this in pictures."

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New Chemical Sensor Makes Finding Landmines and Buried IEDs Easier

A chemical sensing system developed by engineers at the University of Connecticut is believed to be the first of its kind capable of detecting vapors from buried landmines and other explosive devices with the naked eye rather than advanced scientific instrumentation.

The research was first reported in the May 11, 2012 online edition ofAdvanced Functional Materials.

The key to the system is a fluorescent nanofiberous film that can detect ultra-trace levels of explosive vapors and buried explosives when applied to an area where explosives are suspected. A chemical reaction marking the location of the explosive device occurs when the film is exposed to handheld ultraviolet light.

The system can detect nitroaromatics such as those found in TNT and 2,4-DNT (the military's primary explosive and the principle components in landmines) as well as the elements used in harder to detect plastic explosives such as HMX, RDX, Tetryl, and PETN. The ultra-sensitive system can detect elements at levels as low as 10 parts per billion (TNT), 74 parts per trillion (Tetryl), 5 ppt (RDX), 7 ppt (PETN) and 0.1 ppt (HMX) released from one billionth of a gram of explosive residue.

If there is no explosive vapor present, the recyclable film retains a bright fluorescent cyan blue color when exposed to ultraviolet light. If explosive molecules are present, the fluorescence is quenched and a dark circle identifying the threat forms on the film within minutes.

"Our initial results have been very promising," says UConn Dr. Ying Wang, who developed the system as a chemical engineering doctoral student working under the supervision of UConn Associate Engineering Professor Yu Lei. "We are now in the process of arranging a large-scale field test in Sweden."

Rather than using sophisticated chemical modifications or costly synthetic polymers in preparing the sensing material, UConn scientists prepared their ultra-thin film by simply electrospinning pyrene with polystyrene in the presence of an organic salt (tetrabutylammonium hexafluorophosphate or TBAH). This resulted in a highly porous nanofiberous membrane that absorbs explosive vapors at ultra-trace levels quickly and reliably. The film also has excellent sensitivity against common interferences such as ammonium nitrate and inorganic nitrates. Initial vapor detection took place within seconds with more than 90 percent fluorescent quenching efficiency within six minutes.

According to the United Nations, there are an estimated 110 million active landmines hidden underground in 64 countries around the world. It is estimated that as many as 25,000 people are maimed or killed by landmines each year across the globe. The mines not only threaten people's lives, they can paralyze communities by limiting the use of land for farming or roads for trade.

Clearing mines is a slow and deliberative process often involving specially-trained dogs and metal detectors, but each method has its shortcomings. Dogs, considered the gold standard in detection, eventually tire and can experience difficulty differentiating in dense minefields. Metal detectors are prone to false positive readings that can be triggered by buried pieces of metal unrelated to a mine or unexploded ordinance.

While explosive material can be concealed within landmines and IEDs, the seal is often not airtight and small amounts of vapors escape allowing for detection.

The film developed by Wang and Lei is very light weight, similar to paper, and can be rolled out over a suspect area like a sheet. The electrospinning process makes it both easy and affordable to produce.

"We would be very interested in following up on any kind of research that looks at chemical detection systems," says Erik Tollefsen, advisor for stockpile destruction, EOD and technology for the Geneva International Centre for Humanitarian Demining (GICHD). "This is something we might use as a quality control tool for animal detection. There are some cost benefits here."

"The general observation is that chemical detection systems work on a nano-level and our animal-based systems are on the pico-level, which is 1,000 times more sensitive," Tollefsen says. "But obviously with animals, you can't switch them on and off like a machine and they are sometimes difficult to work with."

Wang and Lei have also developed a novel chemical test for detecting TNT in water and other liquids. The application could be used to detect potential terrorist threats in airports as well as groundwater contamination in areas where explosives were used in construction.

The ultra-sensitive, real-time sensor can detect TNT concentrations ranging from about 33 parts per trillion (the equivalent of one drop in 20 Olympic-sized swimming pools) to 225 parts per million.

"Our new sensor based on a recently developed fluorescent polymer for explosives in aqueous samples has two sensing mechanisms in one sensing material, which is very unique," says Lei. "The sensor can easily be incorporated into a paper test strip similar to those used for pregnancy tests, which means it can be produced and used at a very low cost."

Wang and Lei have applied for patents for both chemical sensing systems.

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Dramatic Miniaturization of Metamaterials? Reluctant Electrons Enable 'Extraordinarily Strong' Negative Refraction

In a vacuum, light travels so fast that it would circle Earth more than seven times within the blink of an eye. When light propagates through matter, however, it slows by a factor typically less than 5. This factor, called the refractive index, is positive in naturally occurring materials, and it causes light to bend in a particular direction when it shines on, for example, water or glass.

Over the past two decades, scientists have managed to create artificial materials whose refractive indices are negative; these negative-index metamaterials defy normal experience by bending light in the "wrong" direction. Due to their unusual ability to manipulate electromagnetic waves and their potential to be harnessed for technology (that might, for example, cloak objects from view), negative-index metamaterials have been celebrated by scientists and engineers alike.

Researchers at the Harvard School of Engineering and Applied Sciences (SEAS), collaborating with the Weizmann Institute of Science in Israel, have now demonstrated a drastically new way of achieving negative refraction in a metamaterial.

The advance, reported in the August 2 issue of Nature, results in an "extraordinarily strong" negative refractive index as large as -700, more than a hundred times larger than most previously reported.

"This work may bring the science and technology of negative refraction into an astoundingly miniaturized scale, confining the negatively refracting light into an area that is 10,000 times smaller than many previous negative-index metamaterials," says principal investigator Donhee Ham, Gordon McKay Professor of Electrical Engineering and Applied Physics at SEAS.

The underlying physics of previous work in this field has often involved an entity called magnetic inductance. Ham's research group instead explored kinetic inductance, which is the manifestation of the acceleration of electrons subjected to electric fields, according to Newton's second law of motion.

At its heart, the researchers' change in strategy from using magnetic inductance to kinetic inductance stems from a simple shift in ideas.

"Magnetic inductance represents the tendency of the electromagnetic world to resist change according to Faraday's law," explains Ham. "Kinetic inductance, on the other hand, represents the reluctance to change in the mechanical world, according to Newton's law."

"When electrons are confined perfectly into two dimensions, kinetic inductance becomes much larger than magnetic inductance, and it is this very large two-dimensional kinetic inductance that is responsible for the very strong negative refraction we achieve," explains lead author Hosang Yoon, a graduate student at SEAS. "The dimensionality profoundly affects the condensed-matter electron behaviors, and one of those is the kinetic inductance."

To obtain the large kinetic inductance, Ham and Yoon's work employs a two-dimensional electron gas (2DEG), which forms at the interface of two semiconductors, gallium arsenide and aluminum gallium arsenide. The very "clean" 2DEG sample used in this work was fabricated by coauthor Vladimir Umansky, of the Weizmann Institute.

Ham's team effectively sliced a sheet of 2DEG into an array of strips and used gigahertz-frequency electromagnetic waves (microwaves) to accelerate electrons in the leftmost few strips. The resulting movements of electrons in these strips were "felt" by the neighboring strips to the right, where electrons are consequently accelerated.

In this way, the proof-of-concept device propagates an effective wave to the right, in a direction perpendicular to the strips, each of which acts as a kinetic inductor due to the electrons' acceleration therein. This effective wave proved to exhibit what the researchers call a "staggering" degree of negative refraction.

The primary advantages of the new technology are its ability to localize electromagnetic waves into ultra-subwavelength scales and its dramatically reduced size. This concept demonstrated with microwaves, if extended to other regions of the electromagnetic spectrum, may prove important for operating terahertz and photonic circuits far below their usual diffraction limit, and at near field. It may also one day lead to extremely powerful microscopes and optical tweezers, which are used to trap and study minuscule particles like viruses and individual molecules.

For now, the device operates at temperatures below 20 degrees Kelvin. The researchers note, however, that a similar result can be achieved at room temperature using terahertz waves, which Ham's team is already investigating, with the carbon structure graphene as an alternative two-dimensional conductor.

"While electrons in graphene behave like massless particles, they still possess kinetic energy and can exhibit very large kinetic inductance in a non-Newtonian way," says Ham.

Kitty Y. M. Yeung, a graduate student in applied physics at SEAS, also contributed to the work as coauthor.

This research was supported by the Air Force Office of Scientific Research.

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It's Time to Measure How Intelligent You Are: Brain Imaging can Predict

Brain Imaging Can Predict How Intelligent You Are: 'Global Brain Connectivity' Explains 10 Percent of Variance in Individual Intelligence

When it comes to intelligence, what factors distinguish the brains of exceptionally smart humans from those of average humans?

As science has long suspected, overall brain size matters somewhat, accounting for about 6.7 percent of individual variation in intelligence. More recent research has pinpointed the brain's lateral prefrontal cortex, a region just behind the temple, as a critical hub for high-level mental processing, with activity levels there predicting another 5 percent of variation in individual intelligence.

Now, new research from Washington University in St. Louis suggests that another 10 percent of individual differences in intelligence can be explained by the strength of neural pathways connecting the left lateral prefrontal cortex to the rest of the brain.

Published in the Journal of Neuroscience, the findings establish "global brain connectivity" as a new approach for understanding human intelligence.

"Our research shows that connectivity with a particular part of the prefrontal cortex can predict how intelligent someone is," suggests lead author Michael W. Cole, PhD, a postdoctoral research fellow in cognitive neuroscience at Washington University.

The study is the first to provide compelling evidence that neural connections between the lateral prefrontal cortex and the rest of the brain make a unique and powerful contribution to the cognitive processing underlying human intelligence, says Cole, whose research focuses on discovering the cognitive and neural mechanisms that make human behavior uniquely flexible and intelligent.

"This study suggests that part of what it means to be intelligent is having a lateral prefrontal cortex that does its job well; and part of what that means is that it can effectively communicate with the rest of the brain," says study co-author Todd Braver, PhD, professor of psychology in Arts & Sciences and of neuroscience and radiology in the School of Medicine. Braver is a co-director of the Cognitive Control and Psychopathology Lab at Washington University, in which the research was conducted.

One possible explanation of the findings, the research team suggests, is that the lateral prefrontal region is a "flexible hub" that uses its extensive brain-wide connectivity to monitor and influence other brain regions in a goal-directed manner.

"There is evidence that the lateral prefrontal cortex is the brain region that 'remembers' (maintains) the goals and instructions that help you keep doing what is needed when you're working on a task," Cole says. "So it makes sense that having this region communicating effectively with other regions (the 'perceivers' and 'doers' of the brain) would help you to accomplish tasks intelligently."

While other regions of the brain make their own special contribution to cognitive processing, it is the lateral prefrontal cortex that helps coordinate these processes and maintain focus on the task at hand, in much the same way that the conductor of a symphony monitors and tweaks the real-time performance of an orchestra.

"We're suggesting that the lateral prefrontal cortex functions like a feedback control system that is used often in engineering, that it helps implement cognitive control (which supports fluid intelligence), and that it doesn't do this alone," Cole says.

The findings are based on an analysis of functional magnetic resonance brain images captured as study participants rested passively and also when they were engaged in a series of mentally challenging tasks associated with fluid intelligence, such as indicating whether a currently displayed image was the same as one displayed three images ago.

Previous findings relating lateral prefrontal cortex activity to challenging task performance were supported. Connectivity was then assessed while participants rested, and their performance on additional tests of fluid intelligence and cognitive control collected outside the brain scanner was associated with the estimated connectivity.

Results indicate that levels of global brain connectivity with a part of the left lateral prefrontal cortex serve as a strong predictor of both fluid intelligence and cognitive control abilities.

Although much remains to be learned about how these neural connections contribute to fluid intelligence, new models of brain function suggested by this research could have important implications for the future understanding -- and perhaps augmentation -- of human intelligence.

The findings also may offer new avenues for understanding how breakdowns in global brain connectivity contribute to the profound cognitive control deficits seen in schizophrenia and other mental illnesses, Cole suggests.

Other co-authors include Tal Yarkoni, PhD, a postdoctoral fellow in the Department of Psychology and Neuroscience at the University of Colorado at Boulder; Grega Repovs, PhD, professor of psychology at the University of Ljubljana, Slovenia; and Alan Anticevic, an associate research scientist in psychiatry at Yale University School of Medicine.

Funding from the National Institute of Mental Health supported the study (National Institutes of Health grants MH66088, NR012081, MH66078, MH66078-06A1W1, and 1K99MH096801).

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