Icy giant planets in the laboratory

Even under extremely high pressure, such as those in the interior of Neptune or Uranus, there are stable crystal structures of carbon (orange) and hydrogen (gray). This discovery by HZDR researchers reveals new possibilities for the inner structure of the ice giants.

Giant planets like Uranus and Neptune may contain much less free hydrogen than previously assumed. Researchers from the German Helmholtz-Zentrum Dresden-Rossendorf (HZDR) drove shock waves through two different types of plastic to reach the same temperatures and pressures present inside such planets, and observed the behavior using ultra-strong X-ray laser pulses. Unexpectedly, one of these plastics kept its crystalline structure even at the most extreme pressures reached. Since the icy giant interiors are made up of the same components as the plastic, planetary models may need to be partially reconsidered, as reported in the journal Scientific Reports.

Carbon and hydrogen are among the most abundant elements in the universe, and are a major constituent of icy giant planets such as Uranus and Neptune. In the outer atmosphere, these atoms are found in the form of methane gas, but deeper inside the high pressure can lead to more complex hydrocarbon structures. Predicting the phases and structures that material takes at these conditions is one of the big questions of planetary research.

In order to better understand the structure of the ice giants, an international team led by the two HZDR researchers Dr. Nicholas Hartley and Dr. Dominik Kraus investigated two types of plastic in a laboratory experiment: polystyrene and polyethylene. These materials are similar in chemistry to the hydrocarbon inside the planets. At the SLAC National Accelerator Laboratory in the US, the scientists exposed the samples to conditions predicted to be present around ten thousand kilometers below the surface of Neptune and Uranus. At this depth, the pressure is almost as high as in the core of the earth and two million times higher than the atmospheric pressure on the earth's surface.

Reaching extremely high pressures

At such high pressures and temperatures, the only possible structure that the researchers expected was diamond, or that the samples would be melted. Instead, they observed stable hydrocarbon structures up to the highest pressures reached, but only for the polyethylene samples. "We were very surprised by this result," says Hartley. "We did not expect the different initial state to make such a big difference at such extreme conditions. It's only recently, with the development of brighter X-ray sources, that we're able to study these materials. We were the first to think that it might be possible -- and it was."

Since the extreme conditions inside the ice giants on Earth can only be reached for a brief moment, the researchers need lightning-fast measurement methods. There are only a handful of ultrafast X-ray laser facilities worldwide, and time for measurements is rare and highly demanded. Kraus and Hartley were awarded a total of three twelve hour shifts for their experiments, and so had to use every minute to carry out as many measurement runs as possible. The actual moment where they shock the sample and probe with the X-ray laser takes only a few billionths of a second.

An unexpected structure appears

Even during the experiments, the researchers were able to recognize initial results: "We were very excited because, as hoped, polystyrene formed diamond-like structures of carbon. For polyethylene, however, we saw no diamonds for the conditions reached in this experiment. Instead, there was a new structure that we could not explain at first," Hartley recalls. By comparing the data with previous results at lower pressures, they identified it as a stable structure of polyethylene, which had been seen at five times lower pressure, and only at ambient temperatures.

The discovery of the research team demonstrates how important it is to better characterize the temperature and pressure conditions inside the ice giants, and the chemistry that these lead to, in order to understand their structure and physical properties. Models of Uranus and Neptune assume that the unusual magnetic fields of these planets may originate from free hydrogen, which these results could imply is less common than expected. In the future, the researchers want to use mixtures including oxygen, in order for their experiments to better match the chemistry inside the planets.

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Overland migration of Arctic Terns revealed

Arctic tern.

Data from a landmark study of the world's longest migrating seabird reveals how overland migration is an integral part of their amazing journey.

Analysing the data from electronic tags retrieved from 47 Arctic Terns, the Newcastle University-led team has been able to characterise in unprecedented detail the route and stop-off points during this record-breaking bird's 90,000 km annual migration.

This includes:

• An 8,000km, 24-day, non-stop flight over the Indian Ocean, feeding on the move
• An overland detour from the Farne Irelands to the Irish Sea and over Ireland to the Atlantic
• A short stay on the New Zealand coast before completing the final leg of their journey
• A stop-off at Llangorse Lake, in the Brecon Beacons National Park, during their return journey in the Spring

Led by scientists at Newcastle University, UK, in collaboration with BBC's Springwatch and The National Trust, 53 adult birds nesting on the Farne Islands off the Northumberland coast were fitted with geolocators over a three year period.

Weighing just over 100 g the Arctic Tern has the longest migration of any bird, travelling all the way to Antarctica for the winter and back to the Farnes, which are owned and managed by the National Trust, to breed in the spring.

So far, 47 tags have been retrieved and the research team, led by Dr Chris Redfern of Newcastle University, are starting to analyse the data.

"Technology is revealing details of the movement and behaviour of these amazing birds in unprecedented detail," says Dr Redfern, whose initial findings in collaboration with Dr Richard Bevan are published today in the academic journal Ibis.

"Arctic Terns feed on surface fish and other marine animals so it has always been assumed they would migrate via a coastal route, down the North Sea and through the English Channel.

"But instead our data has shown their regular route is to travel overland across the UK to the Irish Sea and some are going even further crossing Ireland to the North Atlantic."

After that, it's a long hard trek south, down the coast of West Africa and then out across the Indian Ocean.

"Our data suggests their flight over the Indian Ocean is an 8,000 km long haul without a break, probably feeding on the move," says Dr Redfern. "For a bird that weighs less than an iPhone, that's an amazing feat.

"Many of the terns have gone even further, ending up around New Zealand before turning south towards the East Antarctic, finally arriving four months after leaving Northumberland.

"The scale of their migratory journey across featureless oceans is breath-taking! In that context, the UK land mass between the Irish Sea and the Farne Islands must be no obstacle at all to an Arctic Tern and the quickest route to their breeding colony."

The data also highlights key stop-off points off the coast of Lancashire and Wales in April and May as the Terns make their way back to the Farne Islands to breed. Dr Redfern, who carried out the study with Dr Richard Bevan and the Natural History Society of Northumbria, said the detailed picture of Arctic Tern migration patterns would help with future conservation efforts.

"Understanding their behaviour in detail means we can start to build a picture of which areas are important feeding and breeding grounds."

Longest flight ever recorded

More than two thousand pairs of Arctic Terns breed on the Farne Islands. Sitting two miles off the coast of Northumberland, the islands are home to 87,000 pairs of seabird, including Puffin, Eider Duck and Shag. The National Trust has cared for the Farne Islands since 1925.

Previous studies have shown these birds are likely to return each year to the same few square metres of ground, making it an ideal environment to carry out year-to-year tracking studies with geolocators.

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Matter waves and quantum splinters

Rice University physicists and colleagues in Austria and Brazil have shown that shaking ultracold Bose-Einstein condensates (top) can cause them to either divide into the uniform segments characteristic of Faraday waves (center) or shatter into unpredictable splinters (bottom). The frequency of the shaking determines the outcome.

Physicists in the United States, Austria and Brazil have shown that shaking ultracold Bose-Einstein condensates (BECs) can cause them to either divide into uniform segments or shatter into unpredictable splinters, depending on the frequency of the shaking.

"It's remarkable that the same quantum system can give rise to such different phenomena," said Rice University physicist Randy Hulet, co-author of a study about the work published online today in the journal Physical Review X. Hulet's lab conducted the study's experiments using lithium BECs, tiny clouds of ultracold atoms that march in lockstep as if they are a single entity, or matter wave. "The relationship between these states can teach us a great deal about complex quantum many-body phenomena."

The research was conducted in collaboration with physicists at Austria's Vienna University of Technology (TU Wien) and Brazil's University of São Paulo at São Carlos.

The experiments harken to Michael Faraday's 1831 discovery that patterns of ripples were created on the surface of a fluid in a bucket that was shaken vertically at certain critical frequencies. The patterns, known as Faraday waves, are similar to resonant modes created on drumheads and vibrating plates.

To investigate Faraday waves, the team confined BECs to a linear one-dimensional waveguide, resulting in a cigar-shaped BEC. The researchers then shook the BECs using a weak, slowly oscillating magnetic field to modulate the strength of interactions between atoms in the 1D waveguide. The Faraday pattern emerged when the frequency of modulation was tuned near a collective mode resonance.

But the team also noticed something unexpected: When the modulation was strong and the frequency was far below a Faraday resonance, the BEC broke into "grains" of varying size. Rice research scientist Jason Nguyen, lead co-author of the study, found the grain sizes were broadly distributed and persisted for times even longer than the modulation time.

"Granulation is usually a random process that is observed in solids such as breaking glass, or the pulverizing of a stone into grains of different sizes," said study co-author Axel Lode, who holds joint appointments at both TU Wien and the Wolfgang Pauli Institute at the University of Vienna.

Images of the quantum state of the BEC were identical in each Faraday wave experiment. But in the granulation experiments the pictures looked completely different each time, even though the experiments were performed under identical conditions.

Lode said the variation in the granulation experiments arose from quantum correlations -- complicated relationships between quantum particles that are difficult to describe mathematically.

"A theoretical description of the observations proved challenging because standard approaches were unable to reproduce the observations, particularly the broad distribution of grain sizes," Lode said. His team helped interpret the experimental results using a sophisticated theoretical method, and its implementation in software, which accounted for quantum fluctuations and correlations that typical theories do not address.

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New light on origins of modern humans

This is a map showing early African archaeological sites with evidence for symbolic material and microlithic stone tools.

Researchers from the University of Huddersfield, with colleagues from the University of Cambridge and the University of Minho in Braga, have been using a genetic approach to tackle one of the most intractable questions of all -- how and when we became truly human.

Modern Homo sapiens first arose in Africa more than 300,000 years ago, but there is great controversy amongst scholars about whether the earliest such people would have been 'just like us' in their mental capacities -- in the sense that, if they were brought up in a family from Yorkshire today, for example, would they be indistinguishable from the rest of the population? Nevertheless, archaeologists believe that people very like us were living in small communities in an Ice Age refuge on the South African coast by at least 100,000 years ago.

Between around 100,000 and 70,000 years ago, these people left plentiful evidence that they were thinking and behaving like modern humans -- evidence for symbolism, such as the use of pigments (probably for body painting), drawings and engravings, shell beads, and tiny stone tools called microliths that might have been part of bows and arrows. Some of this evidence for what some archaeologists call "modern human behaviour" goes back even further, to more than 150,000 years.

But if these achievements somehow made these people special, suggesting a direct line to the people of today, the genetics of their modern "Khoi-San" descendants in southern Africa doesn't seem to bear this out. Our genomes imply that almost all modern non-Africans from all over the world -- and indeed most Africans too -- are derived from a small group of people living not in South Africa but in East Africa, around 60,000-70,000 years ago. There's been no sign so far that southern Africans contributed to the huge expansion of Homo sapiens out of Africa and across the world that took place around that time.

That is, until now. The Huddersfield-Minho team of geneticists, led by Professor Martin Richards at Huddersfield and Dr Pedro Soares in Braga, along with the eminent Cambridge archaeologist Professor Sir Paul Mellars, have studied the maternally-inherited mitochondrial DNA from Africans in unprecedented detail, and have identified a clear signal of a small-scale migration from South Africa to East Africa that took place at just that time, around 65,000 years ago. The signal is only evident today in the mitochondrial DNA. In the rest of the genome, it seems to have been eroded away to nothing by recombination -- the reshuffling of chromosomal genes between parents every generation, which doesn't affect the mitochondrial DNA -- in the intervening millennia.

The migration signal makes good sense in terms of climate. For most of the last few hundred years, different parts of Africa have been out of step with each other in terms of the aridity of the climate. Only for a brief period at 60,000-70,000 years ago was there a window during which the continent as a whole experienced sufficient moisture to open up a corridor between the south and the east. And intriguingly, it was around 65,000 years ago that some of the signs of symbolism and technological complexity seen earlier in South Africa start to appear in the east.

The identification of this signal opens up the possibility that a migration of a small group of people from South Africa towards the east around 65,000 years ago transmitted aspects of their sophisticated modern human culture to people in East Africa. Those East African people were biologically little different from the South Africans -- they were all modern Homo sapiens, their brains were just as advanced and they were undoubtedly cognitively ready to receive the benefits of the new ideas and upgrade. But the way it happened might not have been so very different from a modern isolated stone-age culture encountering and embracing western civilization today.

In any case, it looks as if something happened when the groups from the South encountered the East, with the upshot being the greatest diaspora of Homo sapiens ever known -- both throughout Africa and out of Africa to settle much of Eurasia and as far as Australia within the space of only a few thousand years.

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Half-a-billion-year-old fossil reveals the origins of comb jellies

One of the ocean's little known carnivores has been allocated a new place in the evolutionary tree of life after scientists discovered its unmistakable resemblance with other sea-floor dwelling creatures.

Comb jellies occupy a pivotal place in the history of animal evolution with some arguing that they were among the first animals to evolve. Now an international team of palaeontologists have found fossil evidence that proves comb jellies are related to ancestors that sat on the sea floor with polyp-like tentacles.

As reported today in Current Biology, researchers from the University of Bristol, Yunnan University in China and London's Natural History Museum, compared a 520 million-year-old fossil with fossils of a similar skeletal structure and found that all evolved from the same ancestors.

The fossil, set in a yellow and olive coloured mudstone and resembling a flower, was found in outcrops south of Kunming in the Yunnan Province, South China by Professor Hou Xianguang, co-author of the study.

Several amazingly preserved fossils have been unearthed from outcrops scattered among rice fields and farmlands in this part of tropical China in the last three decades.

It has been named Daihua after the Dai tribe in Yunnan and the Mandarin word for flower 'Hua', a cup-shaped organism with 18 tentacles surrounding its mouth. On the tentacles are fine feather-like branches with rows of large ciliary hairs preserved.

"When I first saw the fossil, I immediately noticed some features I had seen in comb jellies," said Dr Jakob Vinther, a molecular palaeobiologist from the University of Bristol. "You could see these repeated dark stains along each tentacle that resembles how comb jelly combs fossilise. The fossil also preserves rows of cilia, which can be seen because they are huge. Across the Tree of Life, such large ciliary structures are only found in comb jellies."

In today's oceans, comb jellies are swimming carnivores. Some of them have become invasive pests. They swim using bands of iridescent, rainbow coloured comb rows along their body composed of densely packed cellular protrusions, known as cilia. Their hair-like structures are the largest seen anywhere in the tree of life.

The researchers noticed that Daihua resembled another fossil, a famous weird wonder from the Burgess Shale (508 million years old) called Dinomischus. This stalked creature also had 18 tentacles and an organic skeleton and was previously assigned to a group called entoprocts.

"We also realised that a fossil, Xianguangia, that we always thought was a sea anemone is actually part of the comb jelly branch," said co-author Prof Cong Peiyun.

This emerging pattern led researchers to see a perfect transition from their fossils all the way up to comb jellies.

"It was probably one of the most exhilarating moments of my life," said Dr Vinther. "We pulled out a zoology textbook and tried to wrap our head around the various differences and similarities, and then, bam! -- here is another fossil that fills this gap."

The study shows how comb jellies evolved from ancestors with an organic skeleton, which some still possessed and swam with during the Cambrian. Their combs evolved from tentacles in polyp-like ancestors that were attached to the seafloor. Their mouths then expanded into balloon-like spheres while their original body reduced in size so that the tentacles that used to surround the mouth now emerges from the back-end of the animal.

"With such body transformations, I think we have some of the answers to understand why comb jellies are so hard to figure out. It explains why they have lost so many genes and possess a morphology that we see in other animals," added co-author Dr Luke Parry.

Until around 150 years ago, zoologists had considered comb jellies and cnidarians to be related. This theory was challenged more recently by new genetic information suggesting comb jellies could be a distant relative to all living animals below the very simple looking sponges.

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In a new quantum simulator, light behaves like a magnet

Riccardo Rota and Vincenzo Savona, the two EPFL physicists leading the study, working on the design of their quantum simulator.

When subject to the laws of quantum mechanics, systems made of many interacting particles can display behaviour so complex that its quantitative description defies the capabilities of the most powerful computers in the world. In 1981, the visionary physicist Richard Feynman argued we can simulate such complex behavior using an artificial apparatus governed by the very same quantum laws -- what has come to be known as a "quantum simulator."

One example of a complex quantum system is that of magnets placed at really low temperatures. Close to absolute zero (-273.15 degrees Celsius), magnetic materials may undergo what is known as a "quantum phase transition." Like a conventional phase transition (e.g. ice melting into water, or water evaporating into steam), the system still switches between two states, except that close to the transition point the system manifests quantum entanglement -- the most profound feature predicted by quantum mechanics. Studying this phenomenon in real materials is an astoundingly challenging task for experimental physicists.

But physicists led by Vincenzo Savona at EPFL have now come up with a quantum simulator that promises to solve the problem. "The simulator is a simple photonic device that can easily be built and run with current experimental techniques," says Riccardo Rota, the postdoc at Savona's lab who led the study. "But more importantly, it can simulate the complex behavior of real, interacting magnets at very low temperatures."

The simulator may be built using superconducting circuits -- the same technological platform used in modern quantum computers. The circuits are coupled to laser fields in such a way that it causes an effective interaction among light particles (photons). "When we studied the simulator, we found that the photons behaved in the same way as magnetic dipoles across the quantum phase transition in real materials," says Rota. In short, we can now use photons to run a virtual experiment on quantum magnets instead of having to set up the experiment itself.

"We are theorists," says Savona. "We came up with the idea for this particular quantum simulator and modelled its behavior using traditional computer simulations, which can be done when the quantum simulator addresses a small enough system. Our findings prove that the quantum simulator we propose is viable, and we are now in talks with experimental groups who would like to actually build and use it."

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Paleontologists report world's biggest Tyrannosaurus rex

The towering and battle-scarred 'Scotty' reported by UAlberta paleontologists is the world's largest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada.

University of Alberta paleontologists have just reported the world's biggest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada. The 13-metre-long T. rex, nicknamed "Scotty," lived in prehistoric Saskatchewan 66 million years ago.

"This is the rex of rexes," said Scott Persons, lead author of the study and postdoctoral researcher in the Department of Biological Sciences. "There is considerable size variability among Tyrannosaurus. Some individuals were lankier than others and some were more robust. Scotty exemplifies the robust. Take careful measurements of its legs, hips, and even shoulder, and Scotty comes out a bit heftier than other T. rex specimens."

Scotty, nicknamed for a celebratory bottle of scotch the night it was discovered, has leg bones suggesting a living weight of more than 8,800 kg, making it bigger than all other carnivorous dinosaurs. The scientific work on Scotty has been a correspondingly massive project.

The skeleton was first discovered in 1991, when paleontologists including T. rex expert and UAlberta professor Phil Currie were called in on the project. But the hard sandstone that encased the bones took more than a decade to remove -- only now have scientists been able to study Scotty fully-assembled and realize how unique a dinosaur it is.

It is not just Scotty's size and weight that set it apart. The Canadian mega rex also lays claim to seniority.

"Scotty is the oldest T. rex known," Persons explains. "By which I mean, it would have had the most candles on its last birthday cake. You can get an idea of how old a dinosaur is by cutting into its bones and studying its growth patterns. Scotty is all old growth."

But age is relative, and T. rexes grew fast and died young. Scotty was estimated to have only been in its early 30s when it died.

"By Tyrannosaurus standards, it had an unusually long life. And it was a violent one," Persons said. "Riddled across the skeleton are pathologies -- spots where scarred bone records large injuries."

Among Scotty's injures are broken ribs, an infected jaw, and what may be a bite from another T. rex on its tail -- battle scars from a long life.

"I think there will always be bigger discoveries to be made," said Persons "But as of right now, this particular Tyrannosaurus is the largest terrestrial predator known to science."

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Climate change affecting fish in Ontario lakes

Warmer temperatures are having a ripple effect on food webs in Ontario lakes, according to a new University of Guelph study.

Researchers have found warmer average temperatures over the past decade have forced fish to forage in deeper water. There they hunt different prey species, causing a climate-induced "rewiring" of food webs, altering the flow of energy and nutrients in the lake.

Monitoring the movement of generalist species like lake trout may offer an early warning system for impacts of climate change on ecosystems.

"We can harness the natural capacity of species to detect and respond to changes in their environment," said Tim Bartley, a post-doc in the Department of Integrative Biology and study lead author. "As species are changing their behaviour, they are telling us about what's happening around them in their environment. We can use this information. The behavioural changes we see imply major reorganization of ecosystems."

Published in the journal Nature Ecology and Evolution, the study entailed tracking lake trout movement and feeding in hundreds of lakes in northwestern Ontario.

Bartley caught fish to analyze their tissues to see what they ate. The team also used similar data about fish feeding habits and locations across the province from the Ontario Ministry of Natural Resources.

Tissue analysis showed that lake trout spend more time in deeper water than near shore, although the researchers were unable to identify specific prey species. Lake trout prefer to catch lake herring; Bartley said trout are flexible feeders that will eat other fish species as well as invertebrates.

He said warming may also be pushing lake herring into colder waters, meaning that lake trout may still feed on them in offshore locations.

Monitoring behavioural changes in species such as lake trout is important for humans who rely on ecosystems for resources and services from food to water quality, said Bartley.

Climate change effects are complicated and vary within ecosystems to create a patchwork of new conditions, he said. Other organisms, including lake trout prey, are also moving in response to warming.

Tracking the movement, feeding habits and condition of generalist species such as lake trout may give resource managers an early warning system for detecting the effects of warming.

That's important for managing the entire ecosystem and for looking after populations of lake trout, a popular sport fish for anglers, said Bartley.

But it's not just happening in lakes.

The study also includes data from American researchers showing similar ecosystem "rewiring" in grasslands involving grasshoppers and predatory spiders moving down to cooler areas nearer the soil.

The U of G researchers also point to other studies of climate change effects on rewiring of ecosystems involving beluga whales and halibut in Nunavut, polar bears and ringed seals across the Arctic, and Kodiak bears feeding on elderberries and sockeye salmon on the Pacific coast.

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Blue Brain solves a century-old neuroscience problem

Illustration of morphological types of pyramidal cells within the rodent cortical layer.

New research explains how the shapes of neurons can be classified using mathematical methods from the field of algebraic topology. Neuroscientists can now start building a formal catalogue for all the types of cells in the brain. Onto this catalogue of cells, they can systematically map the function and role in disease of each type of neuron in the brain.

"For nearly 100 years, scientists have been trying to name cells. They have been describing them in the same way that Darwin described animals and trees. Now the Blue Brain Project has developed a mathematical algorithm to objectively classify the shapes of the neurons in the brain," explains Professor Henry Markram, Blue Brain's Founder and Director. "This will allow the development of a standardized taxonomy [classification of cells into distinct groups] of all cells in the brain, which will help researchers compare their data in a more reliable manner."

The team, with lead scientist Lida Kanari, have developed an algorithm to distinguish the different shapes of the most common type of neuron in the neocortex -- the pyramidal cells. Pyramidal cells are distinctively tree-like cells that make up 80% of the neurons in the neocortex and, like antennas, collect information from other neurons in the brain. Basically, they are the redwoods of the forests of trees in the brain. They are excitatory, sending waves of electrical activity through the network, as we perceive, act, and feel.

The father of modern neuroscience, Ramón y Cajal, first drew pyramidal cells over 100 years ago, by looking at them under a microscope. Yet, up until now, scientists have not reached a consensus on the types of pyramidal neurons. Anatomists have been assigning names and debating the different types for the past century, while neuroscience has been unable to tell for sure which types of neurons are subjectively characterized. Even for visibly distinguishable neurons, there is no common ground to consistently define morphological types.

Seventeen types of pyramidal cells

The study from Blue Brain proves for the first time that objective classification of these pyramidal cells is possible, by applying tools from algebraic topology, the branch of mathematics that studies the shape, connectivity, and the emergence of global structure from local constraints.

Blue Brain has pioneered the use of algebraic topology to tackle a wide range of neuroscience problems, and with this study has once again demonstrated its effectiveness. In collaboration with Professors Kathryn Hess at EPFL and Ran Levi from the University of Aberdeen, Blue Brain developed an algorithm, which they then used to objectively classify seventeen types of pyramidal cells in the rat somatosensory cortex. The topological classification does not require expert input, and is proven to be robust.

The structure of most neurons resembles a complex tree, with multiple branches connecting to other neurons and communicating via electrical signals. If we keep the longest (persistent) components of the neuron structure and decompose the smaller branches, we can transform its tree-like structure into a barcode -- a mathematical object that can be used as input for any machine-learning algorithm that will classify the neurons into distinct groups.

"Species" of brain cells

Any neuron classification process is plagued by this question: are two cells that look different just part of a continuum of gradually changing differences (like different "strains" of a species, e.g. different types of dogs) or are they really different "species" of neurons (e.g. dogs, cats, elephants, etc.)? In other words, are they discrete or continuous morphological variations of each other? This can be answered by using the new topological classification and grouping the different "species" of brain cells, each with its own characteristic "strains."

"The Blue Brain Project is digitally reconstructing and simulating the brain, and this research provides one of the solid foundations needed to put all the types of neurons together," explains Kanari. "By removing the ambiguity of cell types, the process of identifying the morphological type of new cells will become fully automated."

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Potential new therapy for liver diseases

Drug therapy may effectively treat a potentially life-threatening condition associated with cirrhosis and other chronic liver diseases, according to a new study by Mayo Clinic researchers. The study was posted in March on Gastroenterology, the online journal of the American Gastroenterological Association. Print publication is scheduled for July.

While therapies have been available to treat some forms of liver disease, including hepatitis C and autoimmune hepatitis, options have been more limited for treating portal hypertension, a condition where there is an increase in pressure within the portal vein that carries blood from abdominal organs to the liver. Portal hypertension is associated with cirrhosis and other chronic liver diseases.

According to the study, the drug sivelestat may effectively lower portal hypertension, improving symptoms and outcomes for those patients. The study results were obtained from mouse models but have since been confirmed in liver samples from humans, according to Vijay Shah, M.D., a Mayo Clinic gastroenterologist and senior author.

"This was an exciting confirmation of our findings and their applicability to human disease," Dr. Shah says. "Sivelestat has been safely used in humans with acute lung injury and bronchopulmonary dysplasia. This suggests that sivelestat and similar drugs constitute a potential means to decrease portal hypertension in patients with chronic liver disease."

The Mayo study showed that deposits of fibrin -- microvascular blood clots -- contributed to portal hypertension, and inflammatory cells known as neutrophils contributed to the formation of fibrin. By inhibiting neutrophil function with sivelestat, they were able to decrease portal hypertension.

"Neutrophils had not previously been identified as significant drivers of portal hypertension," says Moira Hilscher, M.D., the paper's first author. Results were verified in two different models of chronic liver disease.

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