Ten-Year Project Redraws the Map of Bird Brains

Explorers need good maps, which they often end up drawing themselves.

Pursuing their interests in using the brains of birds as a model for the human brain, an international team of researchers led by Duke neuroscientist Erich Jarvis and his collaborators Chun-Chun Chen and Kazuhiro Wada have just completed a mapping of the bird brain based on a 10-year exploration of the tiny cerebrums of eight species of birds.

In a special issue appearing online in the Journal of Comparative Neurology, two papers from the Jarvis group propose a dramatic redrawing of some boundaries and functional areas based on a computational analysis of the activity of 52 genes across 23 areas of the bird brain.

Jarvis, who is a professor of neurobiology at Duke, member of the Duke Institute for Brain Sciences, and a Howard Hughes Medical Institute investigator, said the most important takeaway from the new map is that the brains of all vertebrates, a group that includes birds as well as humans, have some important similarities that can be useful to research.

Most significantly, the new map argues for and supports the existence of columnar organization in the bird brain. "Columnar organization is a rule, rather than an exception found only in mammals," Jarvis said. "One way I visualize this view is that the avian brain is one big, giant gyrus folding around a ventricle space, functioning like what you'd find in the mammalian brain," he said.

To create different patterns of gene expression for the analysis, the birds were exposed to various environmental factors such as darkness or light, silence or bird song, hopping on a treadmill, and in the case of migratory warblers, a magnetic field that stimulated their navigational circuits.

The new map follows up on a 2004 model, proposed by an Avian Brain Nomenclature Consortium, also lead by Jarvis and colleagues, which officially changed a century-old view on the prevailing model that the avian brain contained mostly primitive regions. They argued instead that the avian brain has a cortical-like area and other forebrain regions similar to mammals, but organized differently.

"The change in terminology is small this time, but the change in concept is big," Jarvis said. For this special issue, the of Journal of Comparative Neurology commissioned a commentary by Juan Montiel and Zoltan Molnar, experts in brain evolution, to summarize the large amount of data presented in the studies by the Jarvis group.

One of the major findings is that two populations of cells on either side of a void called the ventricle are actually the same cell types with similar patterns of gene expression. Earlier investigators had thought of the ventricle as a physical barrier separating cell types, but in development studies led by Jarvis' post doctoral fellow Chun-chun Chen, the Duke researchers showed how dividing cells spread in a sheet and flow around the ventricle as they multiply.

The new map simplifies the bird cortex, called pallium, from seven populations of cells down to four major populations. Humans have five populations of cells in six layers.

Part of this refinement is simply that the tools are getting better, says Harvey Karten, a professor of neurosciences at the University of California-San Diego who proposed a dramatic re-thinking of bird cortical organization in the late 1960s. The best tools in that era were microscopes, specific cell stains and electrophysiology. Karten and colleagues are authors of a fourth paper in the special issue which announces a database of gene expression profiles of the avian brain containing some of the data that the Jarvis group used.

Jarvis said having a more specific map is necessary for properly sampling cell populations for gene expression analysis to do even more functional analysis of how the brain operates. As a next step, his team is considering doing an even more detailed bird map with "several hundred" genes rather than the 52 used to make this map.

Jarvis and colleagues are working now on a similar mapping of the crocodile brain with the ultimate goal of being able to say something about how dinosaur brains were organized, since both birds and crocs are descended from them. At a Society for Neuroscience conference in November, they'll be presenting some early findings from that project.

Though the specifics of this newest map may only be of interest within the bird research community, Jarvis said, it builds the awareness that birds can be a useful model for many questions about the human brain.

"Where does the mammalian brain come from?" Karten asks. "And what's the origin of these structures at the cellular and molecular level?" Some neuroscientists have argued that the mammalian cortex -- the one we have -- is something apart from the brains of other vertebrates. Jarvis and Karten now think vertebrate brains have more commonalities than differences.

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How Birds Got Their Wings: Fossil Data Show Scaling of Limbs Altered as Birds Originated from Dinosaurs

Birds originated from a group of small, meat-eating theropod dinosaurs called maniraptorans sometime around 150 million years ago. Recent findings from around the world show that many maniraptorans were very bird-like, with feathers, hollow bones, small body sizes and high metabolic rates.

But the question remains, at what point did forelimbs evolve into wings -- making it possible to fly?

McGill University professor Hans Larsson and a former graduate student, Alexander Dececchi, set out to answer that question by examining fossil data, greatly expanded in recent years, from the period marking the origin of birds.

In a study published in the September issue of Evolution, Larsson and Dececchi find that throughout most of the history of carnivorous dinosaurs, limb lengths showed a relatively stable scaling relationship to body size. This is despite a 5000-fold difference in mass between Tyrannosaurus rex and the smallest feathered theropods from China. This limb scaling changed, however, at the origin of birds, when both the forelimbs and hind limbs underwent a dramatic decoupling from body size. This change may have been critical in allowing early birds to evolve flight, and then to exploit the forest canopy, the authors conclude.

As forelimbs lengthened, they became long enough to serve as an airfoil, allowing for the evolution of powered flight. When coupled with the shrinking of the hind limbs, this helped refine flight control and efficiency in early birds. Shorter legs would have aided in reducing drag during flight -- the reason modern birds tuck their legs as they fly -- and also in perching and moving about on small branches in trees. This combination of better wings with more compact legs would have been critical for the survival of birds in a time when another group of flying reptiles, the pterosaurs, dominated the skies and competed for food.

"Our findings suggest that birds underwent an abrupt change in their developmental mechanisms, such that their forelimbs and hind limbs became subject to different length controls," says Larsson, Canada Research Chair in Macroevolution at McGill's Redpath Museum. Deviations from the rules of how an animal's limbs scale with changes in body size -- another example is the relatively long legs and short arms of humans -- usually indicate some major shift in function or behaviour. "This decoupling may be fundamental to the success of birds, the most diverse class of land vertebrates on Earth today."

"The origin of birds and powered flight is a classic major evolutionary transition," says Dececchi, now a postdoctoral researcher at the University of South Dakota. "Our findings suggest that the limb lengths of birds had to be dissociated from general body size before they could radiate so successfully. It may be that this fact is what allowed them to become more than just another lineage of maniraptorans and led them to expand to the wide range of limb shapes and sizes present in today's birds."

"This work, coupled with our previous findings that the ancestors of birds were not tree dwellers, does much to illuminate the ecology of bird antecedents." says Dr. Dececchi. "Knowing where birds came from, and how they got to where they are now, is crucial for understanding how the modern world came to look the way it is."

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Time Is in the Eye of the Beholder: Time Perception in Animals Depends On Their Pace of Life

An international collaboration led by scientists from Trinity College Dublin including researchers from the University of Edinburgh and the University of St Andrews has shown that animals' ability to perceive time is linked to their pace of life.

The rate at which time is perceived varies across animals. For example, flies owe their skill at avoiding rolled up newspapers to their ability to observe motion on finer timescales than our own eyes can achieve, allowing them to avoid the newspaper in a similar fashion to the "bullet time" sequence in the popular film The Matrix. In contrast, one species of tiger beetle runs faster than its eyes can keep up, essentially becoming blind and requiring it to stop periodically to re-evaluate its prey's position. Even in humans, athletes in various sports have also been shown to quicken their eyes' ability to track moving balls during games.

The study which was just published in the international journal Animal Behaviour, showed that small-bodied animals with fast metabolic rates, such as some birds, perceive more information in a unit of time, hence experiencing time more slowly than large bodied animals with slow metabolic rates, such as large turtles.

Commenting on the findings, Assistant Professor at the School of Natural Sciences at Trinity College Dublin, Andrew Jackson, said: "Ecology for an organism is all about finding a niche where you can succeed that no-one else can occupy. Our results suggest that time perception offers an as yet unstudied dimension along which animals can specialise and there is considerable scope to study this system in more detail. We are beginning to understand that there is a whole world of detail out there that only some animals can perceive and it's fascinating to think of how they might perceive the world differently to us."

"Our results lend support to the importance of time perception in animals where the ability to perceive time on very small scales may be the difference between life and death for fast moving organisms such as predators and their prey," commented lead author Kevin Healy, PhD student at the School of Natural Sciences, Trinity College Dublin. This time perception ability can be shown to vary across all animals, using a phenomenon called the critical flicker fusion frequency. The phenomenon, based on the maximum speed of flashes of light an individual can see before the light source is perceived as constant, is the principle behind the illusion of non-flashing television, computer and cinema screens. This is also the reason pet dogs see flickering televisions, as their eyes have a refresh rate higher than the screen of the TV.

The researchers took advantage of this phenomenon to explain the observed variation in time perception across a broad range of animals, showing that animals that would be expected to be agile possess the most refined ability to see time at high resolutions.

Professor Graeme Ruxton of the University of St Andrews in Scotland, who collaborated on the research project, said "Having eyes that send updates to the brain at much higher frequencies than our eyes do is of no value if the brain cannot process that information equally quickly. Hence, this work highlights the impressive capabilities of even the smallest animal brains. Flies might not be deep thinkers but they can make good decisions very quickly."

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Magnetic Jet Shows How Stars Begin Their Final Transformation

An international team of astronomers have for the first time found a jet of high-energy particles emanating from a dying star. The discovery, by a collaboration of scientists from Sweden, Germany and Australia, is a crucial step in explaining how some of the most beautiful objects in space are formed -- and what happens when stars like the sun reach the end of their lives.

The researchers publish their results in the journal Monthly Notices of the Royal Astronomical Society.

At the end of their lives, stars like the sun transform into some of the most beautiful objects in space: amazing symmetric clouds of gas called planetary nebulae. But how planetary nebulae get their strange shapes has long been a mystery to astronomers.

Scientists at Chalmers University of Technology in Sweden have together with colleagues from Germany and Australia discovered what could be the key to the answer: a high-speed, magnetic jet from a dying star.

Using the CSIRO Australia Telescope Compact Array, an array of six 22-metre radio telescopes in New South Wales, Australia, they studied a star at the end of its life. The star, known as IRAS 15445−5449, is in the process of becoming a planetary nebula, and lies 23,000 light years away in the southern constellation Triangulum Australe (the Southern Triangle).

"In our data we found the clear signature of a narrow and extremely energetic jet of a type which has never been seen before in an old, sun-like star," says Andrés Pérez Sánchez, graduate student in astronomy at Bonn University, who led the study.

The strength of the radio waves of different frequencies from the star match the expected signature for a jet of high-energy particles which are, thanks to strong magnetic fields, accelerated up to speeds close to the speed of light. Similar jets have been seen in many other types of astronomical object, from newborn stars to supermassive black holes.

"What we're seeing is a powerful jet of particles spiralling through a strong magnetic field," says Wouter Vlemmings, astronomer at Onsala Space Observatory, Chalmers. "Its brightness indicates that it's in the process of creating a symmetric nebula around the star."

Right now the star is going through a short but dramatic phase in its development, the scientists believe.

"The radio signal from the jet varies in a way that means that it may only last a few decades. Over the course of just a few hundred years the jet can determine how the nebula will look when it finally gets lit up by the star," says team member Jessica Chapman, astronomer at CSIRO in Sydney, Australia.

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World's Most Vulnerable Areas to Climate Change Mapped

Using data from the world's ecosystems and predictions of how climate change will impact them, scientists from the Wildlife Conservation Society, the University of Queensland, and Stanford University have produced a roadmap that identifies the world's most vulnerable and least vulnerable areas in the Age of Climate Change.

The authors say the vulnerability map will help governments, environmental agencies, and donors identify areas where to best invest in protected area establishment, restoration efforts, and other conservation activities so as to have the biggest return on investment in saving ecosystems and the services they provide to wildlife and people alike.

The study appears in an online version of the journal Nature Climate Change. The authors include: Dr James Watson of the Wildlife Conservation Society and the University of Queensland; Dr Takuya Iwamura of Stanford University; and Nathalie Butt of the University of Queensland.

"We need to realize that climate change is going to impact ecosystems both directly and indirectly in a variety of ways and we can't keep on assuming that all adaptation actions are suitable everywhere. The fact is there is only limited funds out there and we need to start to be clever in our investments in adaptation strategies around the world,," said Dr. James Watson, Director of WCS's Climate Change Program and lead author of the Nature study. "The analysis and map in this study is a means of bringing clarity to complicated decisions on where limited resources will do the most good."

The researchers argue that almost all climate change assessments to date are incomplete in that they assess how future climate change is going to impact landscapes and seascapes, without considering the fact that most of these landscapes have modified by human activities in different ways, making them more or less susceptible to climate change.

A vulnerability map produced in the study examines the relationship of two metrics: how intact an ecosystem is, and how stable the ecosystem is going to be under predictions of future climate change. The analysis creates a rating system with four general categories for the world's terrestrial regions, with management recommendations determined by the combination of factors.

Ecosystems with highly intact vegetation and high relative climate stability, for instance, are the best locations for future protected areas, as these have the best chance of retaining species. In contrast, ecosystems with low levels of vegetation and high relative climate stability could merit efforts at habitat restoration. Ecosystems with low levels of vegetation intactness and low climate stability would be most at risk and would require significant levels of investment to achieve conservation outcomes.

The new map, the authors say, identifies southern and southeastern Asia, western and central Europe, eastern South America, and southern Australia as some of the most vulnerable regions. The analysis differs from previous climate change exposure assessments based on only climate change exposure which shows the most vulnerable regions as central Africa, northern South America, and northern Australia.

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TV Drug Ads: The Whole Truth?

Consumers should be wary when watching those advertisements for pharmaceuticals on the nightly TV news, as six out of 10 claims could potentially mislead the viewer, say researchers in an article published in the Journal of General Internal Medicine.

Researchers Adrienne E. Faerber of The Dartmouth Institute for Health Policy & Clinical Practice and David H. Kreling of The University of Wisconsin-Madison School of Pharmacy found that potentially misleading claims are prevalent throughout consumer-targeted prescription and non-prescription drug advertisements on television.

Over the past 15 years, researchers and policymakers have debated whether drug advertising informs consumers about new drugs, or persuades consumers to take medicines that they may not need. "Healthcare consumers need unrestricted access to high-quality information about health," said Faerber of The Dartmouth Institute, "but these TV drug ads had misleading statements that omitted or exaggerated information. These results conflict with arguments that drug ads are helping inform consumers."

Pharmaceutical companies spent $4.8 billion in 2009, surpassing consumer promotion for nonprescription products of $3 billion that year, the researchers said.

Content for this study came from the Vanderbilt TV News Archive, an indexed archive of recordings of the nightly news broadcasts (the news and commercial segments) on ABC, CBS, and NBC since 1968 and on CNN since 1992. Researchers viewed advertisements in the 6:30𔃅 pm EST period because the nightly news is a desirable time slot for drug advertisers because of the older audience that watches the nightly news.

The researchers reviewed 168 TV advertisements for prescription and over-the-counter drugs aired between 2008 and 2010, and identified statements that were strongly emphasized in the ad. A team of trained analysts then classified those claims as being truthful, potentially misleading or false.

They found that false claims, which are factually false or unsubstantiated, were rare, with only 1 in 10 claims false. False advertising is illegal and can lead to criminal and civil penalties.

Most claims were potentially misleading -- 6 in 10 claims left out important information, exaggerated information, provided opinions, or made meaningless associations with lifestyles, the researchers said.

False or potentially misleading claims may be more frequent in over-the-counter drug ads than ads for prescription drugs -- 6 of 10 claims in prescription drug ads were misleading or false, while 8 of 10 claims in OTC drug ads were misleading or false.

The Food and Drug Administration oversees prescription drug advertising while the Federal Trade Commission oversees advertising for nonprescription drugs.

The FDA and FTC have different definitions of false and misleading claims. For example, the FDA interpretation says prescription drug advertising must include information about the harms of the drug, but information on harms is left out of most OTC drug ads.

The researchers said there were some limitations in the study method: the sample was drawn from a 30-minute period of the TV broadcast day on four major networks, and does not represent all ads on TV. Also, they only analyzed what they determined as the most-emphasized claim in each advertisement and the coders need to interpret the meaning of claims to facilitate analysis, which did introduce subjectivity.

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Tropical Forest Carbon Absorption May Hinge On an Odd Couple

A unique housing arrangement between a specific group of tree species and a carbo-loading bacteria may determine how well tropical forests can absorb carbon dioxide from the atmosphere, according to a Princeton University-based study. The findings suggest that the role of tropical forests in offsetting the atmospheric buildup of carbon from fossil fuels depends on tree diversity, particularly in forests recovering from exploitation.

Tropical forests thrive on natural nitrogen fertilizer pumped into the soil by trees in the legume family, a diverse group that includes beans and peas, the researchers report in the journal Nature. The researchers studied second-growth forests in Panama that had been used for agriculture five to 300 years ago. The presence of legume trees ensured rapid forest growth in the first 12 years of recovery and thus a substantial carbon "sink," or carbon-storage capacity. Tracts of land that were pasture only 12 years before had already accumulated as much as 40 percent of the carbon found in fully mature forests. Legumes contributed more than half of the nitrogen needed to make that happen, the researchers reported.

These fledgling woodlands had the capacity to store 50 metric tons of carbon per hectare (2.47 acres), which equates to roughly 185 tons of carbon dioxide, or the exhaust of some 21,285 gallons of gasoline. That much fuel would take the average car in the United States more than half a million miles. Though the legumes' nitrogen fertilizer output waned in later years, the species nonetheless took up carbon at rates that were up to nine times faster than non-legume trees.

The legumes' secret is a process known as nitrogen fixation, carried out in concert with infectious bacteria known as rhizobia, which dwell in little pods inside the tree's roots known as root nodules. As a nutrient, nitrogen is essential for plant growth, but tropical soil is short on nitrogen and surprisingly non-nutritious for trees. Legumes use secretions to invite rhizobia living in the soil to infect their roots, and the bacteria signal back to initiate nodule growth. The rhizobia move into the root cells of the host plant and -- in exchange for carbohydrates the tree produces by photosynthesis -- convert nitrogen in the air into the fertilizer form that plants need. Excess nitrogen from the legume eventually creates a nitrogen cycle that benefits neighboring trees.

By nurturing bigger, healthier trees that take up more carbon, legumes have a newly realized importance when it comes to influencing atmospheric carbon dioxide, said second author Lars Hedin, a Princeton professor of ecology and evolutionary biology and the Princeton Environmental Institute. Scientists have recently put numbers on how much carbon forests as a whole absorb, with a recent paper suggesting that the world's forests took up 2.4 quadrillion tons of carbon from 1990 to 2007.

"Tropical forests are a huge carbon sink. If trees could just grow and store carbon, you could have a rapid sink, but if they don't have enough nitrogen they don't take up carbon," said Hedin, adding that nitrogen-fixing trees are uncommon in temperate forests such as those in most of North America and Europe.

"Legumes are a group of plants that perform a valuable function, but no one knew how much they help with the carbon sink," Hedin said. "This work shows that they may be critical for the carbon sink, and that the level of biodiversity in a tropical forest may determine the size of the carbon sink."

First author Sarah Batterman, a postdoctoral research associate in Hedin's research group, said legumes, or nitrogen fixers, are especially important for forests recovering from agricultural use, logging, fire or other human activities. The researchers studied 16 forest plots that were formerly pasture and are maintained by the Smithsonian Tropical Research Institute (STRI).

Forest degradation, however, comes with a loss of biodiversity that can affect nitrogen fixers, too, even though legumes are not specifically coveted or threatened, Batterman said. If the numbers and diversity of nitrogen fixers plummet then the health of the surrounding forest would likely be affected for a very long time.

"This study is showing that there is an important place for nitrogen fixation in these disturbed areas," Batterman said. "Nitrogen fixers are a component of biodiversity and they're really important for the function of these forests, but we do not know enough about how this valuable group of trees influences forests. While some species may thrive on disturbance, others are in older forests where they may be sensitive to human activities."

The researchers found that the nine legume species they studied did not contribute nitrogen to surrounding trees at the same time. Certain species were more active in the youngest forests, others in middle-aged forests, and still other species went into action mainly in 300-year-old tracts, though not nearly to the same extent as legumes in younger plots. The researchers found that individual trees reduced their fixation as nitrogen accumulated in soils, with the number of legumes actively fixing nitrogen dropping from 71 to 23 percent between 12- and 80-year-old forests.

"In that way, the diversity of species that are present in the forest is really critical because it ensures that there can be fixation at all different time periods of forest recovery whenever it's necessary," Batterman said. "If you were to lose one of those species and it turned out to be essential for a specific time period, fixation might drop dramatically."

Such details can improve what scientists know about future climate change, Batterman said. Computer models that calculate the global balance of atmospheric carbon dioxide also must factor in sinks that offset carbon, such as tropical forests. And if forests take up carbon differently depending on the abundance and diversity of legumes, models should reflect that variation, she said. Batterman is currently working with Princeton Assistant Professor of Geosciences David Medvigy on a method for considering nitrogen fixation in models.

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Biochemists Resurrect 'Molecular Fossils': Findings Challenge Assumptions About Origins of Life

Before there was life on Earth, there were molecules. A primordial soup. At some point a few specialized molecules began replicating. This self-replication, scientists agree, kick-started a biochemical process that would lead to the first organisms. But exactly how that happened -- how those molecules began replicating -- has been one of science's enduring mysteries.

Now, research from UNC School of Medicine biochemist Charles Carter, PhD, appearing in the September 13 issue of the Journal of Biological Chemistry, offers an intriguing new view on how life began. Carter's work is based on lab experiments during which his team recreated ancient protein enzymes that likely played a vital role in helping create life on Earth. Carter's finding flies in the face of the widely-held theory that Ribonucleic Acid (RNA) self-replicated without the aid of simple proteins and eventually led to life as we know it.

In the early 1980s, researchers found that ribozymes -- RNA enzymes -- act as catalysts. It was evidence that RNA can be both the blueprints and the chemical catalysts that put those blueprints into action. This finding led to the "RNA World" hypothesis, which posits that RNA alone triggered the rise of life from a sea of molecules.

But for the hypothesis to be correct, ancient RNA catalysts would have had to copy multiple sets of RNA blueprints nearly as accurately as do modern-day enzymes. That's a hard sell; scientists calculate that it would take much longer than the age of the universe for randomly generated RNA molecules to evolve sufficiently to achieve the modern level of sophistication. Given Earth's age of 4.5 billion years, living systems run entirely by RNA could not have reproduced and evolved either fast or accurately enough to give rise to the vast biological complexity on Earth today.

"The RNA world hypothesis is extremely unlikely," said Carter. "It would take forever."

Moreover, there's no proof that such ribozymes even existed billions of years ago. To buttress the RNA World hypothesis, scientists use 21st century technology to create ribozymes that serve as catalysts. "But most of those synthetic ribozymes," Carter said, "bear little resemblance to anything anyone has ever isolated from a living system."

Carter, who has been an expert in ancient biochemistry for four decades, took a different approach. His experiments are deeply embedded in consensus biology.

Our genetic code is translated by two super-families of modern-day enzymes. Carter's research team created and superimposed digital three-dimensional versions of the two super-families to see how their structures aligned. Carter found that all the enzymes have virtually identical cores that can be extracted to produce "molecular fossils" he calls Urzymes -- Ur meaning earliest or original. The other parts, he said, are variations that were introduced later, as evolution unfolded.

These two Urzymes are as close as scientists have gotten to the actual ancient enzymes that would have populated Earth billions of years ago.

"Once we identified the core part of the enzyme, we cloned it and expressed it," Carter said. "Then we wanted to see if we could stabilize it and determine if it had any biochemical activity." They could and it did.

Both Urzymes are very good at accelerating the two reactions necessary to translate the genetic code.

"Our results suggest that there were very active protein enzymes very early in the generation of life, before there were organisms," Carter said. "And those enzymes were very much like the Urzymes we've made."

The finding also suggests that Urzymes evolved from even simpler ancestors -- tiny proteins called peptides. And over time those peptides co-evolved with RNA to give rise to more complex life forms.

In this "Peptide-RNA World" scenario, RNA would have contained the instructions for life while peptides would have accelerated key chemical reactions to carry out those instructions.

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Quake-Causing Hotspot Hides Under Eastern U.S.

Is there a blow torch under North America that causes rare, but deadly, earthquakes? Some geologists think they might have found the buried track of just such a hotspot from Missouri to Virginia.

Hotspots are points in Earth’s interior that melt the crust above, generally creating volcanoes. The classic hotspot is the Hawaiian Islands, which stretch out in a line for 1,500 miles, tracing the movement of the Pacific Plate over the Hawaiian hotspot over millions of years. Most hotspots are seen on thinner, oceanic crust, like that of Hawaii. When they burn up through continents, they generally leave their trace in the form of diamond-bearing rocks, which are pretty rare.

But a team of Chinese and American scientists think they have found the track of a hotspot hidden in the very old, thick crust of Eastern United States, based on seismic data from the 2011 Virginia 5.6-magnitude earthquake. That event essentially lit up the structure of the crust in that part of North America for the USArray seismic network to see.

That seismic data has revealed an unexpected scar in the lower part of the crust extending from eastwards from Missouri to Virginia, reported Risheng Chu of the Chinese Academy of Sciences and colleagues in the Sept. 15 issue of the journal Nature Geoscience.

The seismic anomaly, as it is called, cuts through the New Madrid rift system, which is responsible for some of the most powerful earthquakes in North American history. It also crosses a 75-million-year-old diamond-bearing formation in Kentucky. Despite all this, there is no sign of the hotspot track on the surface, they said.

To back up their claim, they created a geodynamic model to show how a plume of heat upwelling from the Earth’s mantle could create just such a seismic feature on the underside of a thick continental crust.

Read more at Discovery News

Origins of Life Found in Smashing Ice

Comets and other icy celestial bodies have some basic building blocks for life, but it takes violent impacts to take them to the next level, according to researchers who claim to have successfully created amino acids in the lab by recreating icy interplanetary collisions.

First the researchers created mixtures of water ice and light organic chemicals roughly based on what has been observed on comets and what is suspected to exist on the Saturn's moons. Then they shocked the ice by firing at it with a steel projectile at very high, interplanetary planetary collision speeds approaching 16,000 miles per hour (7 kilometers per second).

They found that the hypervelocity impact shock of a typical comet ice mixture produced several amino acids, including equal amounts of D- and L-alanine (that means right and left-handed versions of that amino acid molecules). Meanwhile, analyses of the non-shocked "control" samples of the same ice contained none of these important steps towards genuine proteins needed for life. The results suggest that icy impacts within our solar system may play an important role for making ingredients for life.

The team ran the experiment twice, a year apart, to show that their amino acids were not flukes. They also went to great pains to keep their ice mixtures and equipment free of earthly contamination.

"We needed everything to be extremely clean and we needed to show that the results were reproducible," said Zita Martins of Imperial College London and lead author on the paper published in the Sept. 15 issue of Nature Geoscience.

The study is an important step forward because it goes beyond simulations of impacts, of which there are many, she said.

“There are lots of theoretical studies,” said Martins. “But every time they publish they get criticized for not being experimental.” But with the success of this work, it's likely others will follow.

"It's an exciting paper and it's definitely going to spur ancillary work," said icy impacts researcher Michael Mumma of NASA's Goddard Space Flight Center. He is especially interested in what will happen if the experiments are done with a wider range of icy mixtures -- including those that match some of the latest discoveries about the composition of comet ices. "It suggests a whole range of mixtures."

Read more at Discovery News