Volcanoes Wiped out Neanderthals, New Study Suggests

New research suggests that climate change following massive volcanic eruptions drove Neanderthals to extinction and cleared the way for modern humans to thrive in Europe and Asia.
The research, led by Liubov Vitaliena Golovanova and Vladimir Borisovich Doronichev of the ANO Laboratory of Prehistory in St. Petersburg, Russia, is reported in the October issue of Current Anthropology.

"[W]e offer the hypothesis that the Neanderthal demise occurred abruptly (on a geological time-scale) … after the most powerful volcanic activity in western Eurasia during the period of Neanderthal evolutionary history," the researchers write. "[T]his catastrophe not only drastically destroyed the ecological niches of Neanderthal populations but also caused their mass physical depopulation."

Evidence for the catastrophe comes from Mezmaiskaya cave in the Caucasus Mountains of southern Russia, a site rich in Neanderthal bones and artifacts. Recent excavations of the cave revealed two distinct layers of volcanic ash that coincide with large-scale volcanic events that occurred around 40,000 years ago, the researchers say.

Geological layers containing the ashes also hold evidence of an abrupt and potentially devastating climate change. Sediment samples from the two layers reveal greatly reduced pollen concentrations compared to surrounding layers. That's an indication of a dramatic shift to a cooler and dryer climate, the researchers say. Further, the second of the two eruptions seems to mark the end of Neanderthal presence at Mezmaiskaya. Numerous Neanderthal bones, stone tools, and the bones of prey animals have been found in the geological layers below the second ash deposit, but none are found above it.

The ash layers correspond chronologically to what is known as the Campanian Ignimbrite super-eruption which occurred around 40,000 years ago in modern day Italy, and a smaller eruption thought to have occurred around the same time in the Caucasus Mountains. The researchers argue that these eruptions caused a "volcanic winter" as ash clouds obscured the sun's rays, possibly for years. The climatic shift devastated the region's ecosystems, "possibly resulting in the mass death of hominins and prey animals and the severe alteration of foraging zones."

Enter Modern Humans

Anthropologists have long puzzled over the disappearance of the Neanderthals and the apparently concurrent rise of modern humans. Was there some sort of advantage that helped early modern humans out-compete their doomed cousins? This research suggests that advantage may have been simple geographic location.

"Early moderns initially occupied the more southern parts of western Eurasia and Africa and thus avoided much of the direct impact of the … eruptions," the researchers write. And while advances in hunting techniques and social structure clearly aided the survival of modern humans as they moved north, they "may have further benefited from the Neanderthal population vacuum in Europe, allowing wider colonization and the establishment of strong source populations in northern Eurasia."

While the researchers stress that more data from other areas in Eurasia are needed to fully test the volcanic hypothesis, they believe the Mezmaiskaya cave offers "important supporting evidence" for the idea of a volcanic extinction.

Hubble Astronomers Uncover an Overheated Early Universe

If you think global warming is bad, 11 billion years ago the entire universe underwent, well, universal warming.
The consequence was that fierce blasts of radiation from voracious black holes stunted the growth of some small galaxies for a stretch of 500 million years.

This is the conclusion of a team of astronomers who used the new capabilities of NASA's Hubble Space Telescope to probe the invisible, remote universe.

Using the newly installed Cosmic Origins Spectrograph (COS) they have identified an era, from 11.7 to 11.3 billion years ago, when the universe stripped electrons off from primeval helium atoms -- a process called ionization. This process heated intergalactic gas and inhibited it from gravitationally collapsing to form new generations of stars in some small galaxies. The lowest-mass galaxies were not even able to hold onto their gas, and it escaped back into intergalactic space.

Michael Shull of the University of Colorado and his team were able to find the telltale helium spectral absorption lines in the ultraviolet light from a quasar -- the brilliant core of an active galaxy. The quasar beacon shines light through intervening clouds of otherwise invisible gas, like a headlight shining through a fog. The beam allows for a core-sample probe of the clouds of gas interspersed between galaxies in the early universe.

The universe went through an initial heat wave over 13 billion years ago when energy from early massive stars ionized cold interstellar hydrogen from the big bang. This epoch is actually called reionization because the hydrogen nuclei were originally in an ionized state shortly after the big bang.

But Hubble found that it would take another 2 billion years before the universe produced sources of ultraviolet radiation with enough energy to do the heavy lifting and reionize the primordial helium that was also cooked up in the big bang.

This radiation didn't come from stars, but rather from quasars. In fact the epoch when the helium was being reionized corresponds to a transitory time in the universe's history when quasars were most abundant.

The universe was a rambunctious place back then. Galaxies frequently collided, and this engorged supermassive black holes in the cores of galaxies with infalling gas. The black holes furiously converted some of the gravitational energy of this mass to powerful far-ultraviolet radiation that would blaze out of galaxies. This heated the intergalactic helium from 18,000 degrees Fahrenheit to nearly 40,000 degrees. After the helium was reionized in the universe, intergalactic gas again cooled down and dwarf galaxies could resume normal assembly. "I imagine quite a few more dwarf galaxies may have formed if helium reionization had not taken place," said Shull.

So far Shull and his team only have one sightline to measure the helium transition, but the COS science team plans to use Hubble to look in other directions to see if the helium reionization uniformly took place across the universe.

The science team's results will be published in the October 20 issue of The Astrophysical Journal.

Too Much of a Good Thing: Human Activities Overload Ecosystems With Nitrogen

Humans are overloading ecosystems with nitrogen through the burning of fossil fuels and an increase in nitrogen-producing industrial and agricultural activities, according to a new study. While nitrogen is an element that is essential to life, it is an environmental scourge at high levels.
According to the study, excess nitrogen that is contributed by human activities pollutes fresh waters and coastal zones, and may contribute to climate change. Nevertheless, such ecological damage could be reduced by the adoption of time-honored sustainable practices.

Appearing in the October 8, 2010 edition of Science and conducted by an international team of researchers, the study was partially funded by the National Science Foundation.

The Nitrogen Cycle

The nitrogen cycle--which has existed for billions of years--transforms non-biologically useful forms of nitrogen found in the atmosphere into various biologically useful forms of nitrogen that are needed by living things to create proteins, DNA and RNA, and by plants to grow and photosynthesize. The transformation of biologically useful forms of nitrogen to useful forms of nitrogen is known as nitrogen fixation.

Mostly mediated by bacteria that live in legume plant roots and soils, nitrogen fixation and other components of the nitrogen cycle weave and wind through the atmosphere, plants, subsurface plant roots, and soils; the nitrogen cycle involves many natural feedback relationships between plants and microorganisms.

According to the Science paper, since pre-biotic times, the nitrogen cycle has gone through several major phases. The cycle was initially controlled by slow volcanic processes and lightning and then by anaerobic organisms as biological activity started. By about 2.5 billion years ago, as molecular oxygen appeared on Earth, a linked suite of microbial processes evolved to form the modern nitrogen cycle.

Human Impacts on the Nitrogen Cycle

But the start of the 20th century, human contributions to the nitrogen cycle began skyrocketing. "In fact, no phenomenon has probably impacted the nitrogen cycle more than human inputs of nitrogen into the cycle in the last 2.5 billion years," says Paul Falkowski of Rutgers University, a member of the research team.

"Altogether, human activities currently contribute twice as much terrestrial nitrogen fixation as natural sources, and provide around 45 percent of the total biological useful nitrogen produced annually on Earth," says Falkowski. Much of the human contributions of nitrogen into ecosystems come from an 800 percent increase in the use of nitrogen fertilizers from 1960 to 2000.

Another problem: Much of nitrogen fertilizer that is used worldwide is applied inefficiently. As a result, about 60 percent of the nitrogen contained in applied fertilizer is never incorporated into plants and so is free to wash out of root zones, and then pollute rivers, lakes, aquifers and coastal areas through eutrophication. (Eutrophication is a process caused by excess nutrients that depletes oxygen in water bodies and ultimately leads to the death of animal life.)

In addition, some reactions involving nitrogen release nitrogen oxide into the atmosphere. Nitrogen oxide is a greenhouse gas that has 300 times (per molecule) the warming potential of carbon dioxide. In addition, nitrogen oxide destroys stratospheric ozone, which protects the earth from harmful ultraviolet (UV-B) radiation.

Methods to Reduce Nitrogen Overloading

"Natural feedbacks driven by microorganisms will likely produce a new steady-state over time scales of many decades," says Falkowski. "Through this steady state, excess nitrogen added from human sources will be removed at rates equivalent to rates of addition, without accumulating."

But meanwhile, the Earth's population is approaching 7 billion people, and so ongoing pressures for food production are continuing to increase. "There is no way to feed people without fixing huge amounts of nitrogen from the atmosphere, and that nitrogen is presently applied to crop plants very ineffectively." says Falkowski.

So unless promising interventions are taken, the damage done by humans to the Earth's nitrogen cycle will persist for decades or centuries. These promising interventions, which would be designed to reduce the need to use fertilizers that add nitrogen to ecological systems, could include:

* Using systematic crop rotations that would supply nitrogen that would otherwise be provided by fertilizers;
* Optimizing the timing and amounts of fertilizer applications, adopting selected breeding techniques or developing genetically engineered varieties of plants that would increase the efficiency of nitrogen use;
* Using traditional breeding techniques to boost the ability of economically important varieties of wheat, barley and rye to interact favorably with the microbial communities associated with plant root systems and do so in ways that enhance the efficiency of nitrogen use.

"While the processes of eutrophication have been recognized for many years, only recently have scientists been able to begin placing the anthropogenic processes in the context of an understanding of the broader biogeochemical cycles of the planet," says Robert Burnap, an NSF program director. This is an important article because it concisely develops this understanding and also provides reasonable predictions regarding the economic and policy dimensions of the problem."

Family Ties Bind Desert Lizards in Social Groups

Researchers at the University of California, Santa Cruz, have found that a species of lizard in the Mojave Desert lives in family groups and shows patterns of social behavior more commonly associated with mammals and birds. Their investigation of the formation and stability of family groups in desert night lizards (Xantusia vigilis) provides new insights into the evolution of cooperative behavior.
The researchers reported the results of a five-year study of desert night lizards in a paper published in the Proceedings of the Royal Society B: Biological Sciences (published October 6 online in advance of print).

Alison Davis, who led the study as a graduate student at UC Santa Cruz and is currently a postdoctoral researcher at UC Berkeley, said one of the unusual characteristics of desert night lizards is that they are viviparous, giving birth to live young instead of laying eggs. What really got her attention, however, was that both young and old lizards could be found huddling together every winter beneath fallen Joshua trees and other desert plant debris.

"This is remarkable, given the fact that in most species of lizards, individuals actively avoid each other," Davis said.

By conducting extensive genetic analyses of these winter social groups, the researchers found that young desert night lizards stay with their mother, father, and siblings for several years after birth. Some groups aggregated under the same fallen log year after year, forming what the researchers termed dynasties.

According to Davis, about 20 lizard species are thought to form family groups, and only two of those lay eggs. Viviparity (live birth) is crucial for the evolution of cooperative behaviors, she said.

"Viviparity provides the opportunity for prolonged interaction between the mother and offspring, which predisposes the animal to form a family group," Davis said. "The importance of parent-offspring interaction fits with what is currently understood about evolution of family groups and cooperative behaviors in birds and mammals."

In a classic study of animal social behavior published in 1995, Stephen Emlen of Cornell University described the evolution of family groups in birds and mammals and identified common themes and rules seen in both classes of animals. Davis's findings suggest that the same rules also apply to reptiles, which were not considered in Emlen's theory.

"Biologically, lizards are very different from both mammals and birds, yet a few species of lizards have evolved a social system around nuclear family members that is nearly identical to what we see in ground squirrels, primates, and woodpeckers," Davis said.

Coauthor Barry Sinervo, professor of ecology and evolutionary biology at UCSC, said this similarity between widely separated groups of animals makes the findings particularly interesting. "Establishing a common pattern for how kin-based groups and cooperative behaviors evolve across different taxa gives us an invaluable tool. It helps us to predict where similar group behaviors may be found in other species," he said.

The researchers faced some daunting challenges in their quest to understand the family ties that bind desert night lizards. The first hurdle was to capture the lizards. Adults, which are three to five inches long from the snout to the tip of the tail, are not so hard to find. The babies, however, are tiny, about the weight of a toothpick, and perfectly camouflaged, with skin the color of the sand where they are typically found half buried.

"You have to know what you are looking for," Davis said. She and other graduate and undergraduate students in the Sinervo lab looked under hundreds of logs in search of their shy subjects over the course of five years. They eventually marked 2,120 individual lizards for use in the study.

The second challenge was to determine if lizards living in aggregations were actually related and, if so, how closely. Davis worked with Yann Surget-Groba of Bangor University (U.K.) to sort out DNA microsatellite information collected from each lizard aggregation. She recalled Surget-Groba's amazement when he finished his analysis on one particular aggregation of 13 lizards and exclaimed, "They're all related!"

In this paper, the researchers did not address the advantages of baby lizards staying with their mothers for the first few years of life. The young appear to feed themselves and receive no direct care from parents or other siblings. But Davis said that she suspects there are some survival advantages to the group living arrangement and plans to address that subject in a future paper.

"Determining the fitness consequences of kin-based social groups in this species will be an important next step," Sinervo said.

For now, Davis said she hopes that her study will broaden the appreciation of these unusual animals among scientists and the general public. "Anyone interested in animal social behaviors will be interested in this species," she said.

In addition to Davis and Sinervo, the coauthors of the paper include Ammon Corl of UC Santa Cruz and Yann Surget-Groba of Bangor University and the University of Geneva, Switzerland. The study was funded by a grant from the American Museum of Natural History; awards from the American Society of Ichthyologists and Herpetologists and from the U.S. Department of Education; and an NSF postdoctoral fellowship in biology.

'Living Dinosaurs' in Space: Galaxies in Today's Universe Thought to Have Existed Only in Distant Past

Using Australian telescopes, Swinburne University astronomy student Andy Green has found 'living dinosaurs' in space: galaxies in today's Universe that were thought to have existed only in the distant past.

The report of his finding -- Green's first scientific paper -- appears on the cover of the Oct. 7 issue of Nature.

"We didn't think these galaxies existed. We've found they do, but they are extremely rare," said Professor Karl Glazebrook, Green's thesis supervisor and team leader.

The Swinburne researchers have likened the galaxies to the 'living dinosaurs' or Wollemi Pines of space -- galaxies you just wouldn't expect to find in today's world.

"Their existence has changed our ideas about how star formation is fuelled and understanding star formation is important. Just look at the Big Bang, which is how we all got here," Glazebrook said.

The galaxies in question look like disks, reminiscent of our own galaxy, but unlike the Milky Way they are physically turbulent and are forming many young stars.

"Such galaxies were thought to exist only in the distant past, ten billion years ago, when the Universe was less than half its present age," Glazebrook said.

"Stars form from gas, and astronomers had proposed that the extremely fast star formation in those ancient galaxies was fuelled by a special mechanism that could exist only in the early Universe -- cold streams of gas continually falling in."

But finding the same kind of galaxy in today's Universe means that that mechanism can't be the only way such rapid star formation is fuelled. Instead it seems that when young stars form, they create turbulence in their surrounding gas. The more stars are forming in a galaxy, the more turbulence it has.

"Turbulence affects how fast stars form, so we're seeing stars regulating their own formation," Green said.

"It's a bit like a little girl deciding how many siblings she should have." "We still don't know where the gas to make these stars comes from though," he said.

Understanding star formation is one of the most basic, unsolved problems of astronomy. Another significant aspect of the paper is that it was authored by a PhD student.

As Glazebrook pointed out, being first author of a Nature paper as a student is as rare as the galaxies they've discovered. This is an achievement not lost on the young scientist.

"Nature is one of the most prestigious journals in science. It was a pleasant surprise for our work to receive this kind of accolade," Green said.

The study was based on selected galaxies from the Sloan Digital Sky Survey, a kind of census of modern galaxies.

"We studied extreme galaxies to compare them with the ancient Universe," Green said.

He observed them using the Anglo-Australian Telescope (AAT) and the Australian National University's 2.3 metre telescope, both located at Siding Spring Observatory in New South Wales. Professor Matthew Colless, Director of the Australian Astronomical Observatory, which operates the AAT, said that the study highlighted the value of the instruments found at Australia's telescopes.

"They are ideal for studying in detail the nearby counterparts of galaxies seen in the distant Universe by the eight and 10 metre telescopes," he said.

For the next stage of his research, Green plans to use one of these 10 metre telescopes -- in fact the largest optical telescope in the world at the Keck Observatory -- to take an even closer look at the rare galaxies he has discovered.

Green admitted: "Really, we need a bigger telescope, the Giant Magellan Telescope, to understand star formation. But, until it's constructed, Keck is the best tool available."

Green's access to the Keck will be possible thanks to Swinburne's agreement with Caltech, which gives the Swinburne astronomers access to the Keck Observatory in Hawaii for up to 20 nights per year.

Ecological catastrophe': Toxic sludge kills 3

BUDAPEST — The Hungarian government declared a state of emergency on Tuesday after a toxic sludge spill killed at least three people, news agency MTI reported.

The state of emergency affected Veszprem, Gyor-Moson-Sopron and Vas counties. Six people were missing on Tuesday and 120 injured in what officials said was an ecological disaster.

The contaminated mud poured through Kolontar and two other villages on Monday after bursting out of an open containment pond at the nearby Ajkai Timfoldgyar Zrt plant, owned by MAL Zrt.

The sludge, a waste product in aluminum production, contains heavy metals and is toxic if ingested. Many of the injured sustained burns as the sludge seeped through their clothes. Two of the injured were in life threatening condition. An elderly woman, a young man and a 3-year-old child were killed in the flooding.

The chemical burns caused by the sludge could take days to reveal themselves and what may seem like superficial injuries could later cause damage to deeper tissue, Peter Jakabos, a doctor on duty at a hospital in Gyor where several of the injured were taken, said on state television.
Several hundred tons of plaster were being poured into the Marcal river to bind the toxic sludge and prevent it from flowing on, the National Disaster Management Directorate said.

So far, about 35.3 million cubic feet of sludge has leaked from the reservoir and affected an estimated area of 15.4 square miles, Environmental Affairs State Secretary Zoltan Illes told MTI.

Illes said the incident was an "ecological catastrophe" and it was feared that the sludge could reach the Raba and Danube rivers.

Seven towns, including Kolontal, Devecser and Somlovasarhely, were affected near the Ajkai Timfoldgyar plant in the town of Ajka, 100 miles southwest of Budapest, the capital.

'Burned him to the bone'
On Tuesday morning, the sludge in Tunde Erdelyi's house in Devecser was still five feet high and rescue workers used an ax to cut through her living room door to let the red liquid flow out.

"When I heard the rumble of the flood, all the time I had was to jump out the window and run to higher ground," said a tearful Erdelyi, still shocked by the events but grateful that she had been able to save a family rabbit and that her cat was found wet and shivering in the attic.

Robert Kis, Erdelyi's husband, said his uncle had been taken to Budapest, the capital, by helicopter after the sludge "burned him to the bone."

The flood overturned Erdelyi's car and pushed it some 30 yards to the back of the garden while her husband's van was lifted on to a fence.

"We still have some copper in the garage that we could sell to make a living for a while," Kis said as he attempted to appraise the damage to his house and belongings. Erdelyi, a seamstress, was hoping the flood has spared the shop in town where she worked, her family's main source of income.

The disaster agency said 390 residents had to be temporarily relocated and 110 were rescued from the flooded towns, where firefighters and soldiers were carrying out cleanup tasks.

Local environmentalists said that for years they had been calling the government's attention to the risks of red sludge, which in a 2003 report they estimated at 30 million tons.

"Accumulated during decades ... red sludge is, by volume, the largest amount of toxic waste in Hungary," the Clear Air Action Group said.



A woman observes the damage in Devecser on Tuesday, Oct. 5. About 35.3 million cubic feet of sludge has leaked from the reservoir and affected an estimated area of 15.4 square miles. At least three people were killed on Monday when a sludge reservoir at an aluminum factory burst, flooding parts of three villages. (Attila Kisbenedek / AFP


Tunde Erdelyi, left, saves her cat while Janos Kis, right, walks into their yard flooded by toxic mud in the town of Devecser, Hungary, on Tuesday.


A man stands knee-deep in toxic sludge as cleanup efforts begin in Devecser on Tuesday. Seven towns, including Kolontal, Devecser and Somlovasarhely, were affected near the plant.



Firefighters wade through mud flowing in the streets next to a timber trailer in Devecser on Monday.



The broken wall of the reservoir of the Ajka alumina factory in Kolontar, 167 kms southwest of Budapest, Hungary. The chemical sludge flooded the area between Ajka and Devecser. So far one million cubic metres of the chemical red sludge has leaked and it continues to pour endangering thousands of people with an ecological catastrophe. The Hungarian government declared a state of emergency in Veszprem, Gyor-Moson-Sopron and Vas counties. (Gyoergy Varga / EPA)

The Awesome Power of Galaxy Cluster Mergers

The scales are mind-boggling and the physics is cutting edge, so how do you go about simulating the collision of two galactic clusters? Using some of the most powerful computers in the world, researchers at Argonne National Laboratory, the Flash Center at the University of Chicago and the Harvard-Smithsonian Center for Astrophysics have done just that.

A galactic cluster is a group of galaxies held together under their mutual gravity. Occasionally -- during universal history spanning time scales of billions of years -- two clusters will slam into each other at breakneck speeds. But considering these collisions occur in volumes of space measuring in the megaparsecs (one megaparsec is equal to over 3.2 million light-years), it's easy to see why these events take billions of years to merge.

The study of galactic cluster collisions is very important for cosmologists to understand, amongst other things, dark matter. Dark matter, the cosmic phantom, is thought to make up the majority of mass in our Universe. But the problem with dark matter is that it doesn't interact with normal matter, so it cannot be observed directly.

The presence of dark matter can only be observed indirectly, so this means you have to see how the stuff interferes with normal matter gravitationally. To do this, astronomers have to look at the biggest structures in our Universe to stand a hope of detecting it. Also, by simulating cluster collisions and mergers, we can better understand what astronomers are seeing.

In 2006, astronomers announced the first detection of dark matter inside the unfolding collision of two galactic clusters in what is collectively known as the Bullet Cluster. The distribution of normal matter (i.e. the visible gas and galaxies making up the clusters) suggested there had to be another component in the mix: dark matter.

NEWS: Dark Matter Found in Colliding Galaxies

Now, scientists have simulated this awesome collision using a code that creates a 3D representation of two clusters colliding. Looking at how the animation (below) develops, it may as well be the life story of the Bullet Cluster itself.

The code simulates the interaction of both normal matter and dark matter. The normal matter interacts, mixes and generates turbulence as the collision progresses. For this component of the simulation they use a hydrodynamic code -- it's basically the science of how two liquids or gases mix. As the two clouds of dark matter inside each cluster can only interact gravitationally (the dark matter particles cannot collide, or scatter, via any other mechanism), each particle is modeled individually. This an N-body code.

Once the simulation is sent on its way, the mixing of normal matter is simulated along with the dark matter. As the dark matter cores from both clusters reach an equilibrium state, orbiting inside the post-collision cluster, its motion gravitationally mixes the normal matter.

"The dark matter cores slip past and through each other,whereas the two gas components interact and mix," narrator Carrie Eder explains during the collision visualization.

"It is also clearly seen that the mixing of the gas is driven completely by the violent orbital motion of the dark matter cores."

Surprise: Solar System "Force Field" Shrinks Fast

NASA craft reveals unexpected unpredictability of our protective bubble.
Shown in a Hubble Space Telescope image, the "astrosphere" around the star L.L. Orionis approximates the heliosphere around our solar system.

It's cold, dusty, and bereft of planets, but the outskirts of our solar system are anything but dull, according to increasing evidence from NASA's Interstellar Boundary Explorer (IBEX) craft.

As charged particles flow out from the sun, they eventually bump up against interstellar medium—the relatively empty areas between stars. These interactions "inflate" a protective bubble that shields Earth and the entire solar system from potentially harmful cosmic rays .

Now IBEX has surprised astronomers by showing that this force field-like structure, the heliosphere, is an unexpectedly dynamic, unpredictable boundary.

"If we've learned anything from IBEX so far, it is that the models that we're using for interaction of the solar wind with the galaxy were just dead wrong," David McComas, principal investigator for the IBEX program, said during a NASA press conference Thursday.

Heliosphere Changes Fast

For starters, it's been assumed that the heliosphere's expansion and contraction follows the sun's roughly 11-year activity cycle, during which the flow rate of charged particles, or solar wind, fluctuates.

But when scientists compared IBEX maps of the heliosphere taken just six months apart, the researchers found that it had shrunk to a much greater extent than expected. This quick shrinkage could be a concern for astronauts, said McComas, of the Southwest research Institute in San Antonio, Texas. That's because, as the heliosphere shrinks, it lets in more cosmic radiation, which can compromise the body's immune system.

Among IBEX's other new surprises: a long, mysterious ribbon of uncharged particles found last year that has apparently lost its brightest, most energetic region since its 2009 discovery.

"What we're seeing is the knot pull apart as it spreads across a region of the ribbon," McComas said in a press statement.

"To this day the science team can't agree on exactly what causes the knot or the ribbon, but by comparing different sky maps, we find the surprising result that the region is changing over relatively short time periods. Now we have to figure out why."

IBEX's new cosmic-ribbon findings published September 29 in the Journal of Geophysical Research.

Moon Mash-up,

Two of Saturn's moons appear to form a conjoined world in an image from NASA's Cassini orbiter released September 24.

The double-moon effect is aided by the matching reflectivity of Dione (top), which is closer to the camera, and Rhea, which is farther away but slightly larger than Dione. The strategic alignment of a large, faint crater at the "bottom" edge of Dione completes the astronomical illusion.

Mutant Worms Produce Piles of Spider Silk

Snippets of spider genes let mutant silkworms spin silk stronger than steel. Scientists have coaxed miles of spider-like silk from a colony of transgenic silkworms, opening the door for large-scale production of super-strong, tough and flexible fibers.

“We can make a lot more silk from the silkworm process than you could possibly make from spiders,” said molecular biologist Malcolm Fraser of the University of Notre Dame.

Spider silk has long been hailed as a superfiber, useful for everything from surgical sutures to bulletproof vests to scaffolding for growing cartilage. But spiders tend to be predatory loners who turn to cannibalism when raised in close quarters, making it nearly impossible to mass produce the treasured threads. A tapestry on display at the American Museum of Natural History last year took more than a million spiders to produce.

So scientists have tried to pull spider silk from tobacco plants, bacteria and even goats, with mixed success. Silkworms, on the other hand, are natural silk-spinning factories. A worm’s silk gland takes up about a third of its entire body, Fraser said, and a single cocoon can yield a thread up to a mile long. Silkworms have been domesticated for centuries and are already used for making mass quantities of marketable silk.

By inserting specific spider genes into silkworm chromosomes, Fraser and his colleagues grew a colony of caterpillars that produce threads nearly as strong as spider silk.

“We can now make proteins that have the properties of spider silks in a commercializable platform,” Fraser said. Fraser and his collaborators, including biochemist Randy Lewis of the University of Wyoming and Kim Thompson of Kraig Labs, presented the results in a press conference on the Notre Dame campus Sept. 29.

To create the mutant spinners, Fraser and his colleagues used a movable sequence of DNA called the piggyBac transposon to insert snips of spider genes into silkworm embryos. The resulting silk has different properties depending on where in the silkworm chromosome the spider DNA ends up.

“This manipulation allows us to custom build the threads to desired levels of flexibility, tensile strength and toughness,” Fraser said.

Not all the embryos ended up expressing the spider DNA, however. To make sure they knew which worms were transgenic, the researchers attached a gene for red fluorescent protein to the spider DNA, ensuring all the mutants had glowing red eyes. The researchers then bred those caterpillars to raise a stable colony of spider-silk-spinning silkworms.

The resulting thread is actually a hybrid of specially engineered spider silk and natural silkworm silk. Even though they don’t use “straight-up spider silk” — which wouldn’t bond well with the silkworm proteins — the resulting strands are 80 percent as strong, Fraser said. The combination of their strength and flexibility, which materials scientists call toughness, approaches that of Kevlar.

In the wild, some spiders’ silk can be up to 10 times tougher than Kevlar. A spider recently discovered in Madagascar spins threads tougher than any known biological substance.

“We haven’t gotten a hold of that sequence yet, but you can bet that’s going to be something we’re going to engineer into our silkworms,” Fraser said.

The researchers attached another fluorescent protein to the spider genes to make the silk itself glow green. The silk was just as strong, tough and flexible as before, indicating that scientists could attach other genes without diminishing the quality of the silk. One potential application of this feature is making bandages that stimulate the growth of regular skin instead of scar tissue.

“We can basically mix and match spider silk genes,” Fraser said. “It’s like mixing paint — take properties that you want and mix them in, the silkworm has them all expressed and you have a mixture of properties in your silk strand.”

“I think it’s a big step forward,” said biomedical engineer David Kaplan of Tufts University. Until a scientific paper is published, he notes, there’s no way to know how important or useful the silk will prove. But “the principle is very nice,” he said. “I’m anxious to see more.”

Could Genetically Altered Trees, Plants Help Counter Global Warming?

Forests of genetically altered trees and other plants could sequester several billion tons of carbon from the atmosphere each year and so help ameliorate global warming, according to estimates published in the October issue of BioScience.
The study, by researchers at Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory, outlines a variety of strategies for augmenting the processes that plants use to sequester carbon dioxide from the air and convert it into long-lived forms of carbon, first in vegetation and ultimately in soil.

Besides increasing the efficiency of plants' absorption of light, researchers might be able to genetically alter plants so they send more carbon into their roots--where some may be converted into soil carbon and remain out of circulation for centuries. Other possibilities include altering plants so that they can better withstand the stresses of growing on marginal land, and so that they yield improved bioenergy and food crops. Such innovations might, in combination, boost substantially the amount of carbon that vegetation naturally extracts from air, according to the authors' estimates.

The researchers stress that the use of genetically engineered plants for carbon sequestration is only one of many policy initiatives and technical tools that might boost the carbon sequestration already occurring in natural vegetation and crops.

The article, by Christer Jansson, Stan D. Wullschleger, Udaya C. Kalluri, and Gerald A. Tuskan, is the first in a Special Section in the October BioScience that includes several perspectives on the prospects for enhancing biological carbon sequestration. Other articles in the section analyze the substantial ecological and economic constraints that limit such efforts. One article discusses the prospects for sequestering carbon by culturing algae to produce biofuel feedstocks; one proposes a modification of the current regulatory climate for producing genetically engineered trees in the United States; and one discusses societal perceptions of the issues surrounding the use of genetically altered organisms to ameliorate warming attributed to the buildup of greenhouse gases.

Turning Waste Heat Into Power

What do a car engine, a power plant, a factory and a solar panel have in common?

University of Arizona physicists have discovered a new way of harvesting waste heat and turning it into electrical power.

Using a theoretical model of a so-called molecular thermoelectric device, the technology holds great promise for making cars, power plants, factories and solar panels more efficient, to name a few possible applications. In addition, more efficient thermoelectric materials would make ozone-depleting chlorofluorocarbons, or CFCs, obsolete.

The research group led by Charles Stafford, associate professor of physics, published its findings in the September issue of the scientific journal, ACS Nano.

"Thermoelectricity makes it possible to cleanly convert heat directly into electrical energy in a device with no moving parts," said lead author Justin Bergfield, a doctoral candidate in the UA College of Optical Sciences.

"Our colleagues in the field tell us they are pretty confident that the devices we have designed on the computer can be built with the characteristics that we see in our simulations."

"We anticipate the thermoelectric voltage using our design to be about 100 times larger than what others have achieved in the lab," Stafford added.

Catching the energy lost through waste heat has been on the wish list of engineers for a long time but, so far, a concept for replacing existing devices that is both more efficient and economically competitive has been lacking.

Unlike existing heat-conversion devices such as refrigerators and steam turbines, the devices of Bergfield and Stafford require no mechanics and no ozone-depleting chemicals. Instead, a rubber-like polymer sandwiched between two metals acting as electrodes can do the trick.

Car or factory exhaust pipes could be coated with the material, less than 1 millionth of an inch thick, to harvest energy otherwise lost as heat and generate electricity.

The physicists take advantage of the laws of quantum physics, a realm not typically tapped into when engineering power-generating technology. To the uninitiated, the laws of quantum physics appear to fly in the face of how things are "supposed" to behave.

The key to the technology lies in a quantum law physicists call wave-particle duality: Tiny objects such as electrons can behave either as a wave or as a particle.

"In a sense, an electron is like a red sports car," Bergfield said. "The sports car is both a car and it's red, just as the electron is both a particle and a wave. The two are properties of the same thing. Electrons are just less obvious to us than sports cars."

Bergfield and Stafford discovered the potential for converting heat into electricity when they studied polyphenyl ethers, molecules that spontaneously aggregate into polymers, long chains of repeating units. The backbone of each polyphenyl ether molecule consists of a chain of benzene rings, which in turn are built from carbon atoms. The chain link structure of each molecule acts as a "molecular wire" through which electrons can travel.

"We had both worked with these molecules before and thought about using them for a thermoelectric device," Bergfield said, "but we hadn't really found anything special about them until Michelle Solis, an undergrad who worked on independent study in the lab, discovered that, low and behold, these things had a special feature."

Using computer simulations, Bergfield then "grew" a forest of molecules sandwiched between two electrodes and exposed the array to a simulated heat source.

"As you increase the number of benzene rings in each molecule, you increase the power generated," Bergfield said.

The secret to the molecules' capability to turn heat into power lies in their structure: Like water reaching a fork in a river, the flow of electrons along the molecule is split in two once it encounters a benzene ring, with one flow of electrons following along each arm of the ring.

Bergfield designed the benzene ring circuit in such a way that in one path the electron is forced to travel a longer distance around the ring than the other. This causes the two electron waves to be out of phase once they reunite upon reaching the far side of the benzene ring. When the waves meet, they cancel each other out in a process known as quantum interference. When a temperature difference is placed across the circuit, this interruption in the flow of electric charge leads to the buildup of an electric potential -- voltage -- between the two electrodes.

Wave interference is a concept exploited by noise-cancelling headphones: Incoming sound waves are met with counter waves generated by the device, wiping out the offending noise.

"We are the first to harness the wave nature of the electron and develop a concept to turn it into usable energy," Stafford said.

Analogous to solid state versus spinning hard drive type computer memory, the UA-designed thermoelectric devices require no moving parts. By design, they are self-contained, easier to manufacture and easier to maintain compared to currently available technology.

"You could just take a pair of metal electrodes and paint them with a single layer of these molecules," Bergfield said. "That would give you a little sandwich that would act as your thermoelectric device. With a solid-state device you don't need cooling agents, you don't need liquid nitrogen shipments, and you don't need to do a lot of maintenance."

"You could say, instead of Freon gas, we use electron gas," Stafford added.

"The effects we see are not unique to the molecules we used in our simulation," Bergfield said. "Any quantum-scale device where you have a cancellation of electric charge will do the trick, as long as there is a temperature difference. The greater the temperature difference, the more power you can generate."

Molecular thermoelectric devices could help solve an issue currently plaguing photovoltaic cells harvesting energy from sunlight.

"Solar panels get very hot and their efficiency goes down," Stafford said. "You could harvest some of that heat and use it to generate additional electricity while simultaneously cooling the panel and making its own photovoltaic process more efficient."

"With a very efficient thermoelectric device based on our design, you could power about 200 100-Watt light bulbs using the waste heat of an automobile," he said. "Put another way, one could increase the car's efficiency by well over 25 percent, which would be ideal for a hybrid since it already uses an electrical motor."

So, next time you watch a red sports car zip by, think of the hidden power of the electron and how much more efficient that sports car could be with a thermoelectric device wrapped around its exhaust pipe.

Funding for this research was provided by the University of Arizona physics department.

Milky Way Sidelined in Galactic Tug-of-War, Computer Simulation Shows

The Magellanic Stream is an arc of hydrogen gas spanning more than 100 degrees of the sky as it trails behind the Milky Way's neighbor galaxies, the Large and Small Magellanic Clouds. Our home galaxy, the Milky Way, has long been thought to be the dominant gravitational force in forming the Stream by pulling gas from the Clouds.
A new computer simulation by Gurtina Besla (Harvard-Smithsonian Center for Astrophysics) and her colleagues now shows, however, that the Magellanic Stream resulted from a past close encounter between these dwarf galaxies rather than effects of the Milky Way.

"The traditional models required the Magellanic Clouds to complete an orbit about the Milky Way in less than 2 billion years in order for the Stream to form," says Besla. Other work by Besla and her colleagues, and measurements from the Hubble Space Telescope by colleague Nitya Kallivaylil, rule out such an orbit, however, suggesting the Magellanic Clouds are new arrivals and not long-time satellites of the Milky Way.

This creates a problem: How can the Stream have formed without a complete orbit about the Milky Way?

To address this, Besla and her team set up a simulation assuming the Clouds were a stable binary system on their first passage about the Milky Way in order to show how the Stream could form without relying on a close encounter with the Milky Way.

The team postulated that the Magellanic Stream and Bridge are similar to bridge and tail structures seen in other interacting galaxies and, importantly, formed before the Clouds were captured by the Milky Way.

"While the Clouds didn't actually collide," says Besla, "they came close enough that the Large Cloud pulled large amounts of hydrogen gas away from the Small Cloud. This tidal interaction gave rise to the Bridge we see between the Clouds, as well as the Stream."

"We believe our model illustrates that dwarf-dwarf galaxy tidal interactions are a powerful mechanism to change the shape of dwarf galaxies without the need for repeated interactions with a massive host galaxy like the Milky Way."

While the Milky Way may not have drawn the Stream material out of the Clouds, the Milky Way's gravity now shapes the orbit of the Clouds and thereby controls the appearance of the tail.

"We can tell this from the line-of-sight velocities and spatial location of the tail observed in the Stream today," says team member Lars Hernquist of the Center.

The paper describing this work has been accepted for publication in the October 1 issue of the Astrophysical Journal Letters.

Besla's co-authors were Nitya Kallivayalil (MIT Kavli Institute for Astrophysics & Space Research), Lars Hernquist, R. P. van der Marel (STScI), T.J. Cox (Carnegie Observatories) and D. Keres (Harvard-Smithsonian Center for Astrophysics).

An Elegant Galaxy in an Unusual Light

A new image taken with the powerful HAWK-I camera on ESO's Very Large Telescope at Paranal Observatory in Chile shows the beautiful barred spiral galaxy NGC 1365 in infrared light. NGC 1365 is a member of the Fornax cluster of galaxies, and lies about 60 million light-years from Earth.

NGC 1365 is one of the best known and most studied barred spiral galaxies and is sometimes nicknamed the Great Barred Spiral Galaxy because of its strikingly perfect form, with the straight bar and two very prominent outer spiral arms. Closer to the centre there is also a second spiral structure and the whole galaxy is laced with delicate dust lanes.

This galaxy is an excellent laboratory for astronomers to study how spiral galaxies form and evolve. The new infrared images from HAWK-I are less affected by the dust that obscures parts of the galaxy than images in visible light and they reveal very clearly the glow from vast numbers of stars in both the bar and the spiral arms. These data were acquired to help astronomers understand the complex flow of material within the galaxy and how it affects the reservoirs of gas from which new stars can form. The huge bar disturbs the shape of the gravitational field of the galaxy and this leads to regions where gas is compressed and star formation is triggered. Many huge young star clusters trace out the main spiral arms and each contains hundreds or thousands of bright young stars that are less than ten million years old. The galaxy is too remote for single stars to be seen in this image and most of the tiny clumps visible in the picture are really star clusters. Over the whole galaxy, stars are forming at a rate of about three times the mass of our Sun per year.

While the bar of the galaxy consists mainly of older stars long past their prime, many new stars are born in stellar nurseries of gas and dust in the inner spiral close to the nucleus. The bar also funnels gas and dust gravitationally into the very centre of the galaxy, where astronomers have found evidence for the presence of a super-massive black hole, well hidden among myriads of intensely bright new stars.

NGC 1365, including its two huge outer spiral arms, spreads over around 200 000 light-years. Different parts of the galaxy take different times to make a full rotation around the core of the galaxy, with the outer parts of the bar completing one circuit in about 350 million years. NGC 1365 and other galaxies of its type have come to more prominence in recent years with new observations indicating that the Milky Way could also be a barred spiral galaxy. Such galaxies are quite common -- two thirds of spiral galaxies are barred according to recent estimates, and studying others can help astronomers understand our own galactic home.

Which Fertilized Eggs Will Become Healthy Human Fetuses? Researchers Predict With 93% Accuracy

Two-thirds of all human embryos fail to develop successfully. Now, in a new study, researchers at the Stanford University School of Medicine have shown that they can predict with 93 percent certainty which fertilized eggs will make it to a critical developmental milestone and which will stall and die. The findings are important to the understanding of the fundamentals of human development at the earliest stages, which have largely remained a mystery despite the attention given to human embryonic stem cell research.

Because the parameters measured by the researchers in this study occur before any embryonic genes are expressed, the results indicate that embryos are likely predestined for survival or death before even the first cell division. Assessing these parameters in the clinic could make it easier for in vitro fertilization specialists to select embryos for transfer for a successful pregnancy.

"Until recently, we've had so little knowledge about the basic science of our development," said the study's senior author Renee Reijo Pera, PhD. "In addition to beginning to understand more about our development, we're hopeful that our research will help improve pregnancy rates arising from in vitro fertilization, while also reducing the frequency of miscarriage and the need for the selective reduction of multiple embryos."

Reijo Pera is a professor of obstetrics and gynecology at the medical school and the director of the Center for Human Embryonic Stem Cell Research and Education at Stanford's Institute for Stem Cell Biology and Regenerative Medicine. The study will be published online Oct. 3 in Nature Biotechnology. Postdoctoral scholar Connie Wong, PhD, and former postdoctoral scholar Kevin Loewke, PhD, are the co-first authors of the research. Loewke is currently the lead engineer at the Menlo Park, Calif., biotechnology company Auxogyn Inc.

The researchers conducted their studies on a unique set of 242 frozen, one-cell human embryos from the Reproductive Medicine Center at the University of Minnesota. The embryos were created at the in vitro fertilization program at Lutheran General Hospital in Illinois over a period of several years prior to 2002, and when the clinic was closed, the patients gave their consent for their embryos to be used in research.

Nowadays it's unusual to freeze embryos so soon after fertilization (about 12 to 18 hours). Instead, clinicians monitor embryonic development for three to five days in an attempt to identify those that are more likely to result in healthy pregnancies after transfer. Despite their best efforts, though, they have only about a 35 percent success rate. As a result, most women elect to transfer two or more embryos to increase the chance of a live birth. However, if multiple embryos implant and develop successfully, a woman and her physician may choose to selectively abort one or more to better the odds for the remaining embryos.

Reijo Pera and her colleagues received a large grant from an anonymous donor to investigate ways to better predict embryonic developmental success within one or two days of fertilization. Not only would such an advance decrease the likelihood of miscarriage or the possible need for a selective reduction, it would also reduce the amount of time the embryo would be have to be cultured in the laboratory before transfer. (Although it's not been conclusively shown, some researchers are concerned that genetic changes may accumulate in a cultured embryo and cause subtle, long-lasting effects in the fetus.)

The researchers thawed the embryos, split them into four groups and tracked their development during the first few days using time-lapse video microscopy and computer software specially designed by Loewke, a former Stanford mechanical engineering graduate student, for this study. They followed the cells through the development of a hollow ball called a blastocyst, which typically occurs within five to six days after fertilization. A blastocyst is usually an indication of a healthy embryo.

They found that of the 242 embryos, 100 were able within five or six days to form normal-looking blastocysts -- about the same proportion that would be expected to be successful in normal pregnancies. Because they had tracked the embryos' development so closely, they were then able to go back and identify three specific parameters collectively associated with successful blastocyst formation: the duration of first cytokinesis (the last step of a period in the cell cycle called mitosis in which the cell physically divides), the time between first and second mitoses, and the synchronicity of the second and third mitoses. All of these events occur as the embryo progresses from one cell to four cells within the first two days after fertilization.

"It completely surprised me that we could predict embryonic fate so well and so early," said Reijo Pera. If an embryo's values fell within certain windows of time for the three predictive parameters, that embryo was more than 90 percent likely to go on to develop successfully into a blastocyst.

When the researchers looked at the gene expression profiles of individual cells from the embryos, they found that, as had been previously shown, the embryos at first express only genes from the maternally derived egg. By roughly the third day (the eight-cell stage) they begin to express genes specific to embryonic development, and the relative proportion of embryonic to egg genes increases steadily during the next few cell divisions.

Surprisingly, however, they found that not all cells in an embryo are behaving identically: While some cells may be expressing mostly maternal genes, others in the same embryo are churning out mostly embryonic genes.

Similarly, not all cells in an embryo are dividing in synchrony: The researchers found embryos in which some cells were dividing on schedule while others were seemingly stuck, or paused.

"We've always thought of embryos as living or dying, but in reality we find that each cell in the embryo is making decisions autonomously," said Reijo Pera. "No one has ever looked at this before." She and her colleagues found that embryos in which individual cells varied significantly in their cell-division schedules or gene-expression profiles were less likely to become successful blastocysts.

Together the research indicates that the maternal RNA transcripts -- that is, the molecules that carry instructions from the mother's DNA to the embryo's protein-making factories -- must be actively degraded in each cell of the embryo, and that this degradation is necessary for the cells to begin to express embryonic genes. Cells that fail to execute some part of this delicate process get out of sync with their neighbors and jeopardize the life of the embryo. The whole endeavor is complicated, and may explain why human embryonic development is so precarious and unique.

The research also highlights the importance of studying human embryos, which currently cannot be supported by federal funds. (Every year since 1996, Congress has approved a provision known as the Dicky-Wicker amendment that prohibits the use of federal funds for research in which a human embryo is destroyed -- even ones that would otherwise be discarded.)

"In mice, about 80 to 90 percent of embryos develop to the blastocyst stage. In humans, it's about 30 percent," said Reijo Pera. "In addition, about one in 100 mouse embryos are chromosomally abnormal, versus about seven out of 10 human embryos. That's why human studies like these are so important. Women, their families and their physicians want to increase the chances of having one healthy baby and avoid high-risk pregnancies, miscarriages or other adverse maternal and fetal outcomes. It's truly a women's health issue that affects the broader family."

The research was funded by an anonymous donor, the March of Dimes and the Stanford Institute for Stem Cell Biology and Regenerative Medicine.

The researchers have developed an automated algorithm for clinical use that could assess these time-lapse microscopy videos and determine with high accuracy which of these very early embryos would be successful by the four-cell stage. That technology has been licensed exclusively to Auxogyn Inc. by Stanford. Reijo Pera and the other coauthors of the manuscript own or have the right to purchase stock in the company.