Archaeologists uncover ancient trading network in Vietnam

The excavation site at Rach Nui in Southern Vietnam.

A team of archaeologists from The Australian National University (ANU) has uncovered a vast trading network which operated in Vietnam from around 4,500 years ago up until around 3,000 years ago.

A new study shows a number of settlements along the Mekong Delta region of Southern Vietnam were part of a sophisticated scheme where large volumes of items were manufactured and circulated over hundreds of kilometres.

Lead researcher Dr Catherine Frieman School of the ANU School of Archaeology and Anthropology said the discovery significantly changes what was known about early Vietnamese culture.

"We knew some artefacts were being moved around but this shows evidence for a major trade network that also included specialist tool-makers and technological knowledge. It's a whole different ball game," Dr Frieman said.

"This isn't a case of people producing a couple of extra items on top of what they need. It's a major operation."

The discovery was made after Dr Frieman, an expert in ancient stone tools, was brought in to look at a collection of stone items found by researchers at a site called Rach Nui in Southern Vietnam.

Dr Frieman found a sandstone grinding stone used to make tools such as axe heads out of stone believed to come from a quarry located over 80 kilometres away in the upper reaches of the Dong Nai River valley.

"The Rach Nui region had no stone resources. So the people must have been importing the stone and working it to produce the artefacts," she said.

"People were becoming experts in stone tool making even though they live no-where near the source of any stone."

Dr Phillip Piper of the ANU School of Archaeology and Anthropology, an expert in Vietnamese archaeology, is working to map the transition from hunting and gathering to farming across Southeast Asia.

"Vietnam has an amazing archaeological record with a number of settlements and sites that provide significant information on the complex pathways from foraging to farming in the region" Dr Piper said.

"In southern Vietnam, there are numerous archaeological sites of the Neolithic period that are relatively close together, and that demonstrate considerable variation in material culture, methods of settlement construction and subsistence.

Read more at Science Daily

Mechanisms explaining positional diversity of the hindlimb in tetrapod evolution

In the snake embryo, onset of GDF11 function in the prospective vertebra region is later than in other vertebrates' embryos, resulting in a longer flank.

In the evolution of tetrapods, the position of the hindlimb has diversified along with the vertebral formula, which is the number of small bones forming the vertebra. Tetrapods, as the name implies, are species that have four feet. However, this group also includes many other animals without four or any feet, such as snakes and birds. This is because tetrapods include all the organisms, living and extinct, that descended from the last common ancestor of amphibians, reptiles and mammals, even if they have secondarily lost their "four feet."

Although researchers have long studied tetrapod anatomy, how the species-specific position of the body parts of these species -- for example, the hindlimb position along the body -- are formed in early development remains unclear. Elucidating this mystery will be a major step in evolution biology.

This crucial piece of the puzzle has finally been found by a team of researchers from Nagoya University in Japan. The researchers demonstrated that a protein called GDF11, which is involved in embryonic development, plays a vital role in the eventual position of the sacral vertebrae and the hindlimb. The study results were published in July 2017 in Nature Ecology & Evolution.

"In laboratory mice that do not produce the protein GDF11, we have noted that the sacral vertebrae and the hindlimbs are shifted more to the back," said Yoshiyuki Matsubara, researcher at the Division of Biological Science and first author of the study.

To arrive at that conclusion, the research team started by analyzing the expression pattern of the gene of interest and examining the relationship between the pattern and the prospective position of the spine and hindlimb at different development stages in chicken embryos. Next, they tested whether hindlimb positioning can be manipulated by changing the timing of GDF11 activity in the embryos. Lastly, to fully elucidate the role of GDF11 in diversification of the hindlimb position in tetrapods, the team examined the correlation between Gdf11 expression and hindlimb positioning in eight tetrapod species, including the African clawed frog, Chinese soft-shelled turtle, ocelot gecko, Japanese striped snake, chick, quail, emu and mouse.

"Our results also suggest that species-specific hindlimb positioning may have been an effect of the change in the timing or rate of events in the gene that expresses GDF11 during embryonic development," said Takayuki Suzuki, last author of the study.

According to their conclusion, snakes have a long trunk because initiation timing of Gdf11 expression in the developmental stage is much later than that in other tetrapod species.

Read more at Sience Daily

Observations of Red Supergiant Antares Shed Light on the Final Moments of Dying Stars

Antares and Scorpius

One day, our sun will become a red giant, growing so large that it will swallow Earth. That hasn't yet happened, of course, which is fortunate for us on Earth. However, it means scientists must look beyond the solar system to study the full evolutionary cycles of stars and their mechanisms at each stage.

A new study led by Keiichi Ohnaka, a researcher at Catholic University of the North in Chile, sought to understand how the distant red supergiant star Antares manages to expel so much matter off its surface as it nears the end of its life and nears its finale as a spectacular supernova.

The study demonstrated improved techniques for discovering what could be behind atmospheric motion on Antares, while showing that there are still mysteries surrounding what, exactly, causes the star's turbulent churning.

"With this study, we can open a new window to observe stars other than the sun … in a similar way that we observe the sun," Ohnaka told Space.com. "We can then apply this technique to investigate other problems — not only supergiants, like Antares, but also other types of stars and other unsolved problems."

Antares is a red supergiant star, and its large size makes it an ideal candidate for study from Earth. The star is so bright that it was given its name to mean "anti-Ares," likely because its reddish color seemed to oppose that of the shiny planet Mars, named after Ares, the ancient Greek god of war. Because it is so large, Antares is an ideal first subject for scientists to study to gain a better understanding of how stars other than Earth's sun manage to exist and function. Indeed, Antares's diameter is estimated to be 883 times larger than that of the sun. Antares is also known as Alpha Scorpii, meaning it's the brightest star in the constellation Scorpius. The red star is visible in the August night sky.

How can astronomers study distant stars? They certainly cannot travel there with today's technology: A spacecraft flying at the speed of light would take 600 years to arrive at Antares. Ohnaka's group used the European Southern Observatory's Very Large Telescope Interferometer (VLTI) in Cerro Paranal, Chile, to observe the motion of the carbon monoxide gas in Antares's atmosphere.

Until now, scientists have relied on optical and ultraviolet spectroscopy to understand stars, which means they look at light to analyze the chemical compositions of stars. That method is also used to study the sun, but has its limitations. For example, though it can indicate what a star is made of, it cannot show the mechanics of atmospheric gas movement, which could answer questions about what processes Antares experiences. The use of interferometry allows Ohnaka to capture more precise images of the outer parts of distant Antares' atmosphere, down to very small measurements of angles known as milliarseconds. According to Ohnaka, the observations his group made with VLTI's multiple telescopes over the course of five nights in April 2014 were combined to paint a detailed picture of how the gas in Antares' outer atmosphere was moving.

Ohnaka's technical use of VLTI is an important preliminary step in understanding the end stages of stars, according to John Monnier, an astronomer at the University of Michigan who was not involved in the study.

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Antimony Poisoning — Not Lead — May Have Contributed to the Roman Empire’s Fall

A section of the Anio Vetus aqueduct stands in the countryside near Tivoli, 30 kilometers out of Rome, on September 28, 2013.

Lead often takes the blame for the fall of the Roman Empire. Lead water pipes, lead cooking vessels, and lead utensils poisoned unwitting Romans, causing neurological damage, fertility disorders, and other problems — or so the story goes.

But researchers who published a study in the journal Toxicology Letters now claim the theory could be wrong.

Studying a 40-milligram fragment of an ancient lead pipe from Pompeii — the Italian city destroyed by the eruption of the volcano Mt. Vesuvius almost 2,000 year ago — the researchers discovered antimony, a chemical that’s even more toxic than lead.

Given how the inside of lead pipes calcify quickly, forming a barrier between the poisonous lead and the drinking water flowing through the pipe, antimony might have been the real culprit in bringing down one of the world’s great civilizations, said Kaare Lund Rasmussen, a study co-author and an expert in archaeological chemistry at the University of Southern Denmark.

“This is the first time that you see that it is possible they died of antimony poisoning instead of lead poisoning or both,” he said.

A grey metal-like chemical used in making lead batteries, electronics, and other products, antimony is especially common in groundwater near volcanoes, so Rasmussen said it’s crucial to look at pipes in other Roman cities. He expected Italian researchers who have the best access to Roman archeological sites would likely lead that inquiry.

“It’s only one sample,” said Rasmussen. “We know we should measure more.”

A lead pipe sample is analyzed at University of Southern Denmark.

But there’s little doubt Pompeiians were imbibing antimony that quickly causes vomiting, diarrhea, and dehydration, unlike lead poisoning that can take months or even years to develop, he said. Severe antimony poisoning can also damage the liver and kidneys and trigger cardiac arrest.

Rasmussen didn’t know how or why Pompeiians and other Romans might have kept drinking the water if it caused sickness. But he noted that today plenty of people continue to eat unhealthful foods despite health warnings even when those foods might even make them sick — think 39-cent hamburgers, fries, and strawberry shakes.

The levels of antimony in Roman water lines also might have been slight, so the casual water drinker might not have made a connection between quenching their thirst and an upset stomach, he added. “Maybe it’s not so acutely toxic,” he said. “Maybe it was just half or one-tenth of what’s lethal. Then after a while you die from it.”

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Astrophysicists predict Earth-like planet in star system only 16 light years away

This is the GJ832 system.

Astrophysicists at the University of Texas at Arlington have predicted that an Earth-like planet may be lurking in a star system just 16 light years away.

The team investigated the star system Gliese 832 for additional exoplanets residing between the two currently known alien worlds in this system. Their computations revealed that an additional Earth-like planet with a dynamically stable configuration may be residing at a distance ranging from 0.25 to 2.0 astronomical unit (AU) from the star.

"According to our calculations, this hypothetical alien world would probably have a mass between 1 to 15 Earth's masses," said the lead author Suman Satyal, UTA physics researcher, lecturer and laboratory supervisor. The paper is co-authored by John Griffith, UTA undergraduate student and long-time UTA physics professor Zdzislaw Musielak.

The astrophysicists published their findings this week as "Dynamics of a probable Earth-Like Planet in the GJ 832 System" in The Astrophysical Journal.

UTA Physics Chair Alexander Weiss congratulated the researchers on their work, which underscores the University's commitment to data-driven discovery within its Strategic Plan 2020: Bold Solutions | Global Impact.

"This is an important breakthrough demonstrating the possible existence of a potential new planet orbiting a star close to our own," Weiss said. "The fact that Dr. Satyal was able to demonstrate that the planet could maintain a stable orbit in the habitable zone of a red dwarf for more than 1 billion years is extremely impressive and demonstrates the world class capabilities of our department's astrophysics group."

Gliese 832 is a red dwarf and has just under half the mass and radius of our sun. The star is orbited by a giant Jupiter-like exoplanet designated Gliese 832b and by a super-Earth planet Gliese 832c. The gas giant with 0.64 Jupiter masses is orbiting the star at a distance of 3.53 AU, while the other planet is potentially a rocky world, around five times more massive than the Earth, residing very close its host star -- about 0.16 AU.

For this research, the team analyzed the simulated data with an injected Earth-mass planet on this nearby planetary system hoping to find a stable orbital configuration for the planet that may be located in a vast space between the two known planets.

Gliese 832b and Gliese 832c were discovered by the radial velocity technique, which detects variations in the velocity of the central star, due to the changing direction of the gravitational pull from an unseen exoplanet as it orbits the star. By regularly looking at the spectrum of a star -- and so, measuring its velocity -- one can see if it moves periodically due to the influence of a companion.

"We also used the integrated data from the time evolution of orbital parameters to generate the synthetic radial velocity curves of the known and the Earth-like planets in the system," said Satyal, who earned his Ph.D. in Astrophysics from UTA in 2014. "We obtained several radial velocity curves for varying masses and distances indicating a possible new middle planet," the astrophysicist noted.

For instance, if the new planet is located around 1 AU from the star, it has an upper mass limit of 10 Earth masses and a generated radial velocity signal of 1.4 meters per second. A planet with about the mass of the Earth at the same location would have radial velocity signal of only 0.14 m/s, thus much smaller and hard to detect with the current technology.

Read more at Science Daily

Four Earth-sized planets detected orbiting the nearest sun-like star

This illustration compares the four planets detected around the nearby star tau Ceti (top) and the inner planets of our solar system (bottom).

A new study by an international team of astronomers reveals that four Earth-sized planets orbit the nearest sun-like star, tau Ceti, which is about 12 light years away and visible to the naked eye. These planets have masses as low as 1.7 Earth mass, making them among the smallest planets ever detected around nearby sun-like stars. Two of them are super-Earths located in the habitable zone of the star, meaning they could support liquid surface water.

The planets were detected by observing the wobbles in the movement of tau Ceti. This required techniques sensitive enough to detect variations in the movement of the star as small as 30 centimeters per second.

"We are now finally crossing a threshold where, through very sophisticated modeling of large combined data sets from multiple independent observers, we can disentangle the noise due to stellar surface activity from the very tiny signals generated by the gravitational tugs from Earth-sized orbiting planets," said coauthor Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz.

According to lead author Fabo Feng of the University of Hertfordshire, UK, the researchers are getting tantalizingly close to the 10-centimeter-per-second limit required for detecting Earth analogs. "Our detection of such weak wobbles is a milestone in the search for Earth analogs and the understanding of the Earth's habitability through comparison with these analogs," Feng said. "We have introduced new methods to remove the noise in the data in order to reveal the weak planetary signals."

The outer two planets around tau Ceti are likely to be candidate habitable worlds, although a massive debris disc around the star probably reduces their habitability due to intensive bombardment by asteroids and comets.

The same team also investigated tau Ceti four years ago in 2013, when coauthor Mikko Tuomi of the University of Hertfordshire led an effort in developing data analysis techniques and using the star as a benchmark case. "We came up with an ingenious way of telling the difference between signals caused by planets and those caused by star's activity. We realized that we could see how star's activity differed at different wavelengths and use that information to separate this activity from signals of planets," Tuomi said.

The researchers painstakingly improved the sensitivity of their techniques and were able to rule out two of the signals the team had identified in 2013 as planets. "But no matter how we look at the star, there seem to be at least four rocky planets orbiting it," Tuomi said. "We are slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface. This enabled us to essentially verify the existence of the two outer, potentially habitable planets in the system."

Sun-like stars are thought to be the best targets in the search for habitable Earth-like planets due to their similarity to the sun. Unlike more common smaller stars, such as the red dwarf stars Proxima Centauri and Trappist-1, they are not so faint that planets would be tidally locked, showing the same side to the star at all times. Tau Ceti is very similar to the sun in its size and brightness, and both stars host multi-planet systems.

The data were obtained by using the HARPS spectrograph (European Southern Observatory, Chile) and Keck-HIRES (W. M. Keck Observatory, Mauna Kea, Hawaii).

Read more at Science Daily

‘Euro Devil’: Fossil of carnivorous marsupial relative discovered in E Europe

Artist's impression of Anatoliadelphys maasae.

Scientists have discovered fossil remains of a new carnivorous mammal in Turkey, one of the biggest marsupial relatives ever discovered in the northern hemisphere.

The findings, by Dr Robin Beck from the University of Salford in the UK and Dr Murat Maga, of the University of Washington who discovered the fossil, are published today in the journal PLoS ONE.

The new fossil is a 43 million year old cat-sized mammal that had powerful teeth and jaws for crushing hard food, like the modern Tasmanian Devil. It is related to the pouched mammals, or marsupials, of Australia and South America, and it shows that marsupial relatives, or metatherians, were far more diverse in the northern hemisphere than previously believed.

Dr Maga found the fossil at a site near the town of Kazan, northwest of the Turkish capital, Ankara. It has been named Anatoliadelphys maasae, after the ancient name for Turkey, and Dr Mary Maas, a Turkish-American palaeontologist. The fossil is remarkably well preserved, and includes parts of the skull and most of the skeleton.

It shows that Anatoliadelphys weighed 3-4 kilograms, about the size of a domestic cat, and that it was capable of climbing. It had powerful teeth and jaws, for eating animals and possibly crushing bones. Features of the teeth and bones of Anatoliadelphys show that is closely related to marsupials, but it is not known whether it had a pouch or not.

Dr Beck, who is a world expert in the evolution of marsupials and their fossil relatives, said: "This was definitely an odd little beast -- imagine something a bit like a mini-Tasmanian devil that could climb trees.

"It could probably have eaten pretty much anything it could catch -- beetles, snails, frogs, lizards, small mammals, bones, and probably some plant material as well. This find changes what we thought we knew about the evolution of marsupial relatives in the northern hemisphere -- they were clearly a far more diverse bunch than we ever suspected."

Most fossil metatherians from the northern hemisphere were insect-eating creatures no bigger than mice or rats, whereas Anatoliadelphys was ten times larger and could have eaten vertebrate prey.

"It might seem odd to find a fossil of a marsupial relative in Turkey, but the ancestors of marsupials actually originated in the northern hemisphere, and they survived there until about 12 million years ago," said Dr Beck.

The region of Turkey where Anatoliadelphys was found was probably an island 43 million years ago, which may have enabled Anatoliadelphys to survive without competition from carnivorous placental mammals, such as fossil relatives of cats, dogs and weasels.

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Ancient Algae Blooms May Explain the Rise of Animals on Earth

Sally-lightfoot Crabs (Grapsus grapsus) feeding on algae at low tide, Ecuador, Galapagos Islands, James Island

For nearly three billion years, the evolution of life on Earth remained mostly stalled at the single-cell stage, yielding a watery world teeming with bacteria. 

But then the melting some 650 million years ago of “Snowball Earth” — when oceans at the equator were frozen to a depth of two kilometers (1.2 miles) — led to a global algae bloom that changed everything, researchers reported Wednesday.

"Microscopic bacteria were replaced by much larger algae" fed by nutrients ripped from mountainsides as glaciers slid toward the sea, said Jochen Brocks, a professor at Australian National University and lead author of a study published in Nature.

"These organisms revolutionized the base of the food web and, without them, we would not be here today," he told AFP while attending an international geochemistry conference in Paris, where he presented his findings.

When and why animals first appeared on the planet has been one of the great, and most durable, mysteries in science.

Up to now, there have been more theories than hard facts, with experts divided into two main camps on the origin of complex organisms, said Brocks, whose own findings pushed him from one camp to the other.

"The fight has been going on for two decades," he said by phone. "I was just in a session at the conference, and they are really butting heads."

One side, populated mainly by biologists, contends there is really no puzzle to be solved — the evolution of something as intricate as an animal genome takes time, even billions of years, they argue. The constraints, in other words, were intrinsic and not environmental.

"The second camp says that animals could have evolved more quickly, but that something was holding them back," Brocks said.

Insufficient oxygen has long been seen as a crucial barrier to the rise of multi-cellular life. Large, energy-consuming organisms need a powerful fuel — and the oxygen to help burn it.

Brocks's research also supports a bottleneck hypothesis, but points in a different direction.

Coincidence 'very unlikely'

"Our study presents the first real evidence that it was not oxygen that was lacking, but an abundant, nutritious food source," he said.  

Which brings us back to algae.

Vast amounts of nitrogen-rich nutrients tumbled into the sea as Earth's surface melted, allowing photosynthesizing algae to proliferate at the expense of far-smaller bacteria.

The bottom of the food chain determines how much energy is in the ecosystem, and algae are on average 1,000 times bigger than bacteria.

"Proportionally, it is the difference between a mouse to an elephant — in ocean ecology, size is all that really matters," Brocks said.

"You suddenly had a huge amount of nutritious, high-energy particles at the base of the food web that then drives the entire ecosystem towards complex, large creatures."

Read more at Seeker

Boron nitride foam soaks up carbon dioxide

A microscope image shows the high surface area of hexagonal-boron nitride foam glued together with polyvinyl alcohol. The tough, light foam can be used to soak up carbon dioxide or as a material to shield biological tissues from lasers.

Rice University materials scientists have created a light foam from two-dimensional sheets of hexagonal-boron nitride (h-BN) that absorbs carbon dioxide.

They discovered freeze-drying h-BN turned it into a macro-scale foam that disintegrates in liquids. But adding a bit of polyvinyl alcohol (PVA) into the mix transformed it into a far more robust and useful material.

The foam is highly porous and its properties can be tuned for use in air filters and as gas absorption materials, according to researchers in the Rice lab of materials scientist Pulickel Ajayan.

Their work appears in the American Chemical Society journal ACS Nano.

The polyvinyl alcohol serves as a glue. Mixed into a solution with flakes of h-BN, it binds the junctions as the microscopic sheets arrange themselves into a lattice when freeze-dried. The one-step process is scalable, the researchers said.

"Even a very small amount of PVA works," said co-author and Rice postdoctoral researcher Chandra Sekhar Tiwary. "It helps make the foam stiff by gluing the interconnects between the h-BN sheets -- and at the same time, it hardly changes the surface area at all."

In molecular dynamics simulations, the foam adsorbed 340 percent of its own weight in carbon dioxide. The greenhouse gas can be evaporated out of the material, which can be reused repeatedly, Tiwary said. Compression tests showed the foam got stiffer through 2,000 cycles as well.

And when coated with PDMS, another polymer, the foam becomes an effective shield from lasers that could be used in biomedical, electronics and other applications, he said.

Ultimately, the researchers want to gain control over the size of the material's pores for specific applications, like separating oil from water. Simulations carried out by co-author Cristiano Woellner, a joint postdoctoral researcher at Rice and the State University of Campinas, Brazil, could serve as a guide for experimentalists.

"It's important to join experiments and theoretical calculations to see the mechanical response of this composite," Woellner said. "This way, experimentalists will see in advance how they can improve the system."

Rice graduate student Peter Owuor is lead author of the paper. Co-authors are Ok-Kyung Park, a visiting scholar at Rice and a postdoctoral researcher at Chonbuk National University, Republic of Korea; Rice postdoctoral researchers Almaz Jalilov and Rodrigo Villegas Salvatierra and graduate students Luong Xuan Duy, Sandhya Susarla and Jarin Joyner; Rice alumnus Sehmus Ozden, now a postdoctoral fellow at Los Alamos National Laboratory; Robert Vajtai, a senior faculty fellow at Rice; Jun Lou, a Rice professor of materials science and nanoengineering; and James Tour, Rice's T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering; and Professor Douglas Galvão of the State University of Campinas. Ajayan is chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

Read more at Science Daily

Scientists use magnetic fields to remotely stimulate brain -- and control body movements

Scientists have used magnetic nanoparticles to stimulate neurons deep in the brain to evoke body movements of mice. This image shows a section of a mouse brain with injected magnetic nanoparticles (colored red) covering targeted cells in the striatum.

Scientists have used magnetism to activate tiny groups of cells in the brain, inducing bodily movements that include running, rotating and losing control of the extremities -- an achievement that could lead to advances in studying and treating neurological disease.

The technique researchers developed is called magneto-thermal stimulation. It gives neuroscientists a powerful new tool: a remote, minimally invasive way to trigger activity deep inside the brain, turning specific cells on and off to study how these changes affect physiology.

"There is a lot of work being done now to map the neuronal circuits that control behavior and emotions," says lead researcher Arnd Pralle, PhD, a professor of physics in the University at Buffalo College of Arts and Sciences. "How is the computer of our mind working? The technique we have developed could aid this effort greatly."

Understanding how the brain works -- how different parts of the organ communicate with one another and control behavior -- is key to developing therapies for diseases that involve the injury or malfunction of specific sets of neurons. Traumatic brain injuries, Parkinson's disease, dystonia and peripheral paralysis all fall into this category.

The advances reported by Pralle's team could also aid scientists seeking to treat ailments such as depression and epilepsy directly through brain stimulation.

The study, which was done on mice, was published Aug. 15 in eLife, an open-source, peer-review journal. Pralle's team included first authors Rahul Munshi, a UB PhD candidate in physics, and Shahnaz Qadri, PhD, a UB postdoctoral researcher, along with researchers from UB, Philipps University of Marburg in Germany and the Universidad de Santiago de Compostela in Spain.

Magneto-thermal stimulation involves using magnetic nanoparticles to stimulate neurons outfitted with temperature-sensitive ion channels. The brain cells fire when the nanoparticles are heated by an external magnetic field, causing the channels to open.

Targeting highly specific brain regions

In mice, Pralle's team succeeded in activating three distinct regions of the brain to induce specific motor functions.

Stimulating cells in the motor cortex caused the animals to run, while stimulating cells in the striatum caused the animals to turn around. When the scientists activated a deeper region of the brain, the mice froze, unable to move their extremities.

"Using our method, we can target a very small group of cells, an area about 100 micrometers across, which is about the width of a human hair," Pralle says.

How magneto-thermal stimulation works

Magneto-thermal stimulation enables researchers to use heated, magnetic nanoparticles to activate individual neurons inside the brain.

Here's how it works: First, scientists use genetic engineering to introduce a special strand of DNA into targeted neurons, causing these cells to produce a heat-activated ion channel. Then, researchers inject specially crafted magnetic nanoparticles into the same area of the brain. These nanoparticles latch onto the surface of the targeted neurons, forming a thin covering like the skin of an onion.

When an alternating magnetic field is applied to the brain, it causes the nanoparticles' magnetization to flip rapidly, generating heat that warms the targeted cells. This forces the temperature-sensitive ion channels to open, spurring the neurons to fire.

The particles the researchers used in the new eLife study consisted of a cobalt-ferrite core surrounded by a manganese-ferrite shell.

An advance over other methods, like optogenetics

Pralle has been working to advance magneto-thermal stimulation for about a decade. He previously demonstrated the technique's utility in activating neurons in a petri dish, and then in controlling the behavior of C. elegans, a tiny nematode.

Pralle says magneto-thermal stimulation has some benefits over other methods of deep-brain stimulation.

One of the best-known techniques, optogenetics, uses light instead of magnetism and heat to activate cells. But optogenetics typically requires implantation of tiny fiber optic cables in the brain, whereas magneto-thermal stimulation is done remotely, which is less invasive, Pralle says. He adds that even after the brains of mice were stimulated several times, targeted neurons showed no signs of damage.

Read more at Science Daily

Supermassive black holes feed on cosmic jellyfish

Observations of 'Jellyfish galaxies' with ESO's Very Large Telescope have revealed a previously unknown way to fuel supermassive black holes. It seems the mechanism that produces the tentacles of gas and newborn stars that give these galaxies their nickname also makes it possible for the gas to reach the central regions of the galaxies, feeding the black hole that lurks in each of them and causing it to shine brilliantly. This picture of one of the galaxies, nicknamed JO204, from the MUSE instrument on ESO's Very Large Telescope in Chile, shows clearly how material is streaming out of the galaxy in long tendrils to the lower-left. Red shows the glow from ionised hydrogen gas and the whiter regions are where most of the stars in the galaxy are located. Some more distant galaxies are also visible.

An Italian-led team of astronomers used the MUSE (Multi-Unit Spectroscopic Explorer) instrument on the Very Large Telescope (VLT) at ESO's Paranal Observatory in Chile to study how gas can be stripped from galaxies. They focused on extreme examples of jellyfish galaxies in nearby galaxy clusters, named after the remarkable long "tentacles" of material that extend for tens of thousands of light-years beyond their galactic discs.

The tentacles of jellyfish galaxies are produced in galaxy clusters by a process called ram pressure stripping. Their mutual gravitational attraction causes galaxies to fall at high speed into galaxy clusters, where they encounter a hot, dense gas which acts like a powerful wind, forcing tails of gas out of the galaxy's disc and triggering starbursts within it.

Six out of the seven jellyfish galaxies in the study were found to host a supermassive black hole at the centre, feeding on the surrounding gas. This fraction is unexpectedly high -- among galaxies in general the fraction is less than one in ten.

"This strong link between ram pressure stripping and active black holes was not predicted and has never been reported before," said team leader Bianca Poggianti from the INAF-Astronomical Observatory of Padova in Italy. "It seems that the central black hole is being fed because some of the gas, rather than being removed, reaches the galaxy centre."

A long-standing question is why only a small fraction of supermassive black holes at the centres of galaxies are active. Supermassive black holes are present in almost all galaxies, so why are only a few accreting matter and shining brightly? These results reveal a previously unknown mechanism by which the black holes can be fed.

Yara Jaffe, an ESO fellow who contributed to the paper explains the significance: "These MUSE observations suggest a novel mechanism for gas to be funnelled towards the black hole's neighbourhood. This result is important because it provides a new piece in the puzzle of the poorly understood connections between supermassive black holes and their host galaxies."

The current observations are part of a much more extensive study of many more jellyfish galaxies that is currently in progress.

Read more at Science Daily

Mystery of how first animals appeared on Earth solved

Associate Professor Jochen Brocks and Dr. Amber Jarrett with an oil sample taken ancient sedimentary rocks.

Research led by The Australian National University (ANU) has solved the mystery of how the first animals appeared on Earth, a pivotal moment for the planet without which humans would not exist.

Lead researcher Associate Professor Jochen Brocks said the team found the answer in ancient sedimentary rocks from central Australia.

"We crushed these rocks to powder and extracted molecules of ancient organisms from them," said Dr Brocks from the ANU Research School of Earth Sciences.

"These molecules tell us that it really became interesting 650 million years ago. It was a revolution of ecosystems, it was the rise of algae."

Dr Brocks said the rise of algae triggered one of the most profound ecological revolutions in Earth's history, without which humans and other animals would not exist.

"Before all of this happened, there was a dramatic event 50 million years earlier called Snowball Earth," he said.

"The Earth was frozen over for 50 million years. Huge glaciers ground entire mountain ranges to powder that released nutrients, and when the snow melted during an extreme global heating event rivers washed torrents of nutrients into the ocean."

Dr Brocks said the extremely high levels of nutrients in the ocean, and cooling of global temperatures to more hospitable levels, created the perfect conditions for the rapid spread of algae. It was the transition from oceans being dominated by bacteria to a world inhabited by more complex life, he said.

"These large and nutritious organisms at the base of the food web provided the burst of energy required for the evolution of complex ecosystems, where increasingly large and complex animals, including humans, could thrive on Earth," Dr Brocks said.

The research is published in Nature, and the findings will be presented at the Goldschmidt Conference in Paris, France, this week.

Co-lead researcher Dr Amber Jarrett discovered ancient sedimentary rocks from central Australia that related directly to the period just after the melting of Snowball Earth.

"In these rocks we discovered striking signals of molecular fossils," said Dr Jarrett, an ANU Research School of Earth Sciences PhD graduate.

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Cosmic magnifying lens reveals inner jets of black holes

Illustration shows a likely configuration of a gravitational lensing system discovered by OVRO. The 'milli-lens' is located in or near the intervening spiral galaxy. The lens is magnifying blobs of jet material within the active galaxy PKS1413+135, but the blobs are too small to be seen in the radio image (top left), taken by MOJAVE. Only when the blobs move far away from the yellow core do they expand and are visible as the pink blobs in the image.

Astronomers using Caltech's Owens Valley Radio Observatory (OVRO) have found evidence for a bizarre lensing system in space, in which a large assemblage of stars is magnifying a much more distant galaxy containing a jet-spewing supermassive black hole. The discovery provides the best view yet of blobs of hot gas that shoot out from supermassive black holes.

"We have known about the existence of these clumps of material streaming along black hole jets, and that they move close to the speed of light, but not much is known about their internal structure or how they are launched," says Harish Vedantham, a Caltech Millikan Postdoctoral Scholar. "With lensing systems like this one, we can see the clumps closer to the central engine of the black hole and in much more detail than before." Vedantham is lead author of two new studies describing the results in the Aug. 15 issue of The Astrophysical Journal. The international project is led by Anthony Readhead, the Robinson Professor of Astronomy, Emeritus, and director of the OVRO.

Many supermassive black holes at the centers of galaxies blast out jets of gas traveling near the speed of light. The gravity of black holes pulls material toward them, but some of that material ends up ejected away from the black hole in jets. The jets are active for one to 10 million years -- every few years, they spit out additional clumps of hot material. With the new gravitational lensing system, these clumps can be seen at scales about 100 times smaller than before.

"The clumps we're seeing are very close to the central black hole and are tiny -- only a few light-days across. We think these tiny components moving at close to the speed of light are being magnified by a gravitational lens in the foreground spiral galaxy," says Readhead. "This provides exquisite resolution of a millionth of a second of arc, which is equivalent to viewing a grain of salt on the moon from Earth."

A critical element of this lensing system is the lens itself. The scientists think that this could be the first lens of intermediate mass -- which means that it is bigger than previously observed "micro" lenses consisting of single stars and smaller than the well-studied massive lenses as big as galaxies. The lens described in the new paper, dubbed a "milli-lens," is thought to be about 10,000 solar masses, and most likely consists of a cluster of stars. An advantage of a milli-sized lens is that it is small enough not to block the entire source, which allows the jet clumps to be magnified and viewed as they travel, one by one, behind the lens. What's more, the researchers say the lens itself is of scientific interest because not much is known about objects of this intermediate-mass range.

"This system could provide a superb cosmic laboratory for both the study of gravitational milli-lensing and the inner workings of the nuclear jet in an active galaxy," says Readhead.

The new findings are part of an OVRO program to obtain twice-weekly observations of 1,800 active supermassive black holes and their host galaxies, using OVRO's 40-meter telescope, which detects radio emissions from celestial objects. The program has been running since 2008 in support of NASA's Fermi mission, which observes the same galaxies in higher-energy gamma rays.

In 2010, the OVRO researchers noticed something unusual happening with the galaxy in the study, an active galaxy called PKS 1413+ 135. Its radio emission had brightened, faded, and then brightened again in a very symmetrical fashion over the course of a year. The same type of event happened again in 2015. After a careful analysis that ruled out other scenarios, the researchers concluded that the overall brightening of the galaxy is most likely due to two successive high-speed clumps ejected by the galaxy's black hole a few years apart. The clumps traveled along the jet and became magnified when they passed behind the milli-lens.

"It has taken observations of a huge number of galaxies to find this one object with the symmetrical dips in brightness that point to the presence of a gravitational lens," says coauthor Timothy Pearson, a senior research scientist at Caltech who helped discover in 1981 that the jet clumps travel at close to the speed of light. "We are now looking hard at all our other data to try to find similar objects that can give a magnified view of galactic nuclei."

The next step to confirm the PKS 1413+ 135 results is to observe the galaxy with a technique called very-long-baseline interferometry (VLBI), in which radio telescopes across the globe work together to image cosmic objects in detail. The researchers plan to use this technique beginning this fall to look at the galaxy and its supermassive black hole, which is expected to shoot out another clump of jet material in the next few years. With the VLBI technique, they should be able to see the clump smeared out into an arc across the sky via the light-bending effects of the milli-lens. Identifying an arc would confirm that indeed a milli-lens is magnifying the ultra-fast jet clumps spewing from a supermassive black hole.

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Unique imaging of a dinosaur's skull tells evolutionary tale

This is a 3-D image of Bistahieversor sealeyi, which was found in the Bisti Badlands in New Mexico and Imaged at Los Alamos' unique facilities.

Researchers using Los Alamos' unique neutron-imaging and high-energy X-ray capabilities have exposed the inner structures of the fossil skull of a 74-million-year-old tyrannosauroid dinosaur nicknamed the Bisti Beast in the highest-resolution scan of tyrannosaur skull ever done. The results add a new piece to the puzzle of how these bone-crushing top predators evolved over millions of years.

"Normally, we look at a variety of thick, dense objects at Los Alamos for defense programs, but the New Mexico Museum of Natural History and Science was interested in imaging a very large fossil to learn about what's inside," said Ron Nelson, of the Laboratory's Physics Division. Nelson was part of a team that included staff from Los Alamos National Laboratory, the museum, the University of New Mexico and the University of Edinburgh. "It turns out that high energy neutrons are an interesting and unique way to image something of this size."

The results helped the team determine the skull's sinus and cranial structure. Initial viewing of the computed tomography (CT) slices showed preservation of un-erupted teeth, the brain cavity, internal structure in some bones, sinus cavities, pathways of some nerves and blood vessels, and other anatomical structures. These imaging techniques have revolutionized the study of paleontology over the past decade, allowing paleontologists to gain essential insights into the anatomy, development and preservation of important specimens. Team members will present their findings on the fossil, Bistahieversor sealeyi, August 23 at the annual Society of Vertebrate Paleontology meeting in Calgary, Alberta.

To peer inside the 40-inch skull, which was found in 1996 in the Bisti/De-Na-Zin Wilderness Area near Farmington, N.M. the Los Alamos team combined neutron and X-ray CT to extract anatomical information not accessible otherwise and without the risk of damaging the irreplaceable fossil. Los Alamos is one of a few places in the world that can perform both methods on samples ranging from the very small to the very large scale.

The thickness of the skull required higher energy X-rays than those typically available to adequately penetrate the fossil. The Lab's microtron electron accelerator produced sufficiently high-energy X-rays.

To provide an alternate view inside the skull, the team also used a newly developed, high-energy neutron imaging technique with neutrons produced by the proton accelerator at the Los Alamos Neutron Science Center (LANSCE). The neutrons interact with the nuclei rather than the electrons in the skull, as X-rays do, and thus have different elemental sensitivity. This provides complementary information to that obtained with X-rays.

The team's study illuminates the Bisti Beast's place in the evolutionary tree that culminated in Tyrannosaurus rex.

"The CT scans help us figure out how the different species within the T. rex family related to each other and how they evolved," said Thomas Williamson, Curator of Paleontology at the New Mexico museum. "The Bistahieversor represents the most basal tyrannosaur to have the big-headed, bone-crushing adaptations and almost certainly the small forelimbs. It was living alongside species more closely related to T. rex, the biggest and most derived tyrannosaur of all, which lived about 66 million years ago. Bistahieversor lived almost 10 million years before T. rex, but it also was a surviving member of a lineage that retained many of the primitive features from even farther back closer to when tyrannosaurs underwent their transition to bone-crushing."

The Bisti Beast skull is the largest object to date for which full, high-resolution neutron and X-ray CT scans have been performed at the Laboratory and required innovations both to image the entire skull and to handle the image reconstruction from the resulting large data sets.

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Seven complete specimens of new flower, all 100 million years old

Tropidogyne pentaptera. 100-million-year-old fossilized flower identified and named by OSU researchers George Poinar Jr. and Kenton Chambers.

A Triceratops or Tyrannosaurus rex bulling its way through a pine forest likely dislodged flowers that 100 million years later have been identified in their fossilized form as a new species of tree.

George Poinar Jr., professor emeritus in Oregon State University's College of Science, said it's the first time seven complete flowers of this age have been reported in a single study. The flowers range from 3.4 to 5 millimeters in diameter, necessitating study under a microscope.

Poinar and collaborator Kenton Chambers, professor emeritus in OSU's College of Agricultural Sciences, named the discovery Tropidogyne pentaptera based on the flowers' five firm, spreading sepals; the Greek word for five is "penta," and "pteron" means wing.

"The amber preserved the floral parts so well that they look like they were just picked from the garden," Poinar said. "Dinosaurs may have knocked the branches that dropped the flowers into resin deposits on the bark of an araucaria tree, which is thought to have produced the resin that fossilized into the amber. Araucaria trees are related to kauri pines found today in New Zealand and Australia, and kauri pines produce a special resin that resists weathering."

This study builds on earlier research also involving Burmese amber in which Poinar and Chambers described another species in the same angiosperm genus, Tropidogyne pikei; that species was named for its flower's discoverer, Ted Pike. Findings were recently published in Paleodiversity.

"The new species has spreading, veiny sepals, a nectar disc, and a ribbed inferior ovary like T. pikei," Poinar said. "But it's different in that it's bicarpellate, with two elongated and slender styles, and the ribs of its inferior ovary don't have darkly pigmented terminal glands like T. pikei."

Both species have been placed in the extant family Cunoniaceae, a widespread Southern Hemisphere family of 27 genera.

Poinar said T. pentaptera was probably a rainforest tree.

"In their general shape and venation pattern, the fossil flowers closely resemble those of the genus Ceratopetalum that occur in Australia and Papua-New Guinea," he said. "One extant species is C. gummiferum, which is known as the New South Wales Christmas bush because its five sepals turn bright reddish pink close to Christmas."

Another extant species in Australia is the coach wood tree, C. apetalum, which like the new species has no petals, only sepals. The towering coach wood tree grows to heights of greater than 120 feet, can live for centuries and produces lumber for flooring, furniture and cabinetwork.

So what explains the relationship between a mid-Cretaceous Tropidogyne from Myanmar, formerly known as Burma, and an extant Ceratopetalum from Australia, more than 4,000 miles and an ocean away to the southeast?

That's easy, Poinar said, if you consider the geological history of the regions.

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Cassini says goodbye to a true Titan

These two views of Saturn's moon Titan exemplify how NASA's Cassini spacecraft has revealed the surface of this fascinating world.

Mere weeks away from its dramatic, mission-ending plunge into Saturn, NASA's Cassini spacecraft has a hectic schedule, orbiting the planet every week in its Grand Finale. On a few orbits, Saturn's largest moon, Titan, has been near enough to tweak Cassini's orbit, causing the spacecraft to approach Saturn a bit closer or a bit farther away. A couple of those distant passes even pushed Cassini into the inner fringes of Saturn's rings.

Titan will be waiting once again when the road runs out in September. A last, distant encounter with the moon on Sept. 11 will usher Cassini to its fate, with the spacecraft sending back precious science data until it loses contact with Earth.

But this gravitational pushing and shoving isn't a new behavior for Titan. It's been doing that all along, by design.

The True Engine of the Mission

Repeated flybys of Titan were envisioned, from the mission's beginning, as a way to explore the mysterious planet-size moon and to fling Cassini toward its adventures in the Saturn system. Scientists had been eager for a return to Titan since NASA's Voyager 1 spacecraft flew past in 1980 and was unable to see through the dense, golden haze that shrouds its surface.

Titan is just a bit larger than the planet Mercury. Given its size, the moon has significant gravity, which is used for bending Cassini's course as it orbits Saturn. A single close flyby of Titan could provide more of a change in velocity than the entire 90-minute engine burn the spacecraft needed to slow down and be captured by Saturn's gravity upon its arrival in 2004.

The mission's tour designers -- engineers tasked with plotting the spacecraft's course, years in advance -- used Titan as their linchpin. Frequent passes by the moon provided the equivalent of huge amounts of rocket propellant. Using Titan, Cassini's orbit could be stretched out, farther from Saturn -- for example, to send the spacecraft toward the distant moon Iapetus. With this technique, engineers used Titan flybys to change the orientation of Cassini's orbit many times during the mission; for example, lifting the spacecraft out of the plane of the rings to view them from high above, along with high northern and southern latitudes on Saturn and its moons.

What We've Learned

Over the course of its 13-year mission at Saturn, Cassini has made 127 close flybys of Titan, with many more-distant observations. Cassini also dropped off the European Space Agency's Huygens probe, which descended through Titan's atmosphere to land on the surface in January 2005.

Successes for Cassini during its mission include the revelation that, as researchers had theorized, there were indeed bodies of open liquid hydrocarbons on Titan's surface. Surprisingly, it turned out Titan's lakes and seas are confined to the poles, with almost all of the liquid being at northern latitudes in the present epoch. Cassini found that most of Titan has no lakes, with vast stretches of linear dunes closer to the equator similar to those in places like Namibia on Earth. The spacecraft observed giant hydrocarbon clouds hovering over Titan's poles and bright, feathery ones that drifted across the landscape, dropping methane rain that darkened the surface. There were also indications of an ocean of water beneath the moon's icy surface.

Early on, Cassini's picture of Titan was spotty, but every encounter built upon the previous one. Over the course of the entire mission, Cassini's radar investigation imaged approximately 67 percent of Titan's surface, using the spacecraft's large, saucer-shaped antenna to bounce signals off the moon's surface. Views from Cassini's imaging cameras, infrared spectrometer, and radar slowly and methodically added details, building up a more complete, high-resolution picture of Titan.

"Now that we've completed Cassini's investigation of Titan, we have enough detail to really see what Titan is like as a world, globally," said Steve Wall, deputy lead of Cassini's radar team at NASA's Jet Propulsion Laboratory in Pasadena, California.

Scientists now have enough data to understand the distribution of Titan's surface features (like mountains, dunes and seas) and the behavior of its atmosphere over time, and they have been able to begin piecing together how surface liquids might migrate from pole to pole.

Among the things that remain uncertain is exactly how the methane in Titan's atmosphere is being replenished, since it's broken down over time by sunlight. Scientists see some evidence of volcanism, with methane-laden water as the "lava," but a definitive detection remains elusive.

Cassini's long-term observations could still provide clues. Researchers have been watching for summer rain clouds to appear at the north pole, as their models predicted. Cassini observed rain clouds at the south pole in southern summer in 2004. But so far, clouds at high northern latitudes have been sparse.

"The atmosphere seems to have more inertia than most models have assumed. Basically, it takes longer than we thought for the weather to change with the seasons," said Elizabeth Turtle, a Cassini imaging team associate at Johns Hopkins Applied Physics Laboratory, Laurel, Maryland.

The sluggish arrival of northern summer clouds may match better with models that predict a global reservoir of methane, Turtle said. "There isn't a global reservoir at the surface, so if one exists in the subsurface that would be a major revelation about Titan." This points to the value of Cassini's long-term monitoring of Titan's atmosphere, she said, as the monitoring provides data that can be used to test models and ideas.

Results from the Last Close Pass

Cassini made its last close flyby of Titan on April 22. That flyby gave the spacecraft the push it needed to leap over Saturn's rings and begin its final series of orbits, which pass between the rings and the planet.

During that flyby, Cassini's radar was in the driver's seat -- its observation requirements determining how the spacecraft would be oriented as it passed low over the surface one last time at an altitude of 608 miles (979 kilometers). One of the priorities was to have one last look for the mysterious features the team dubbed "magic islands," which had appeared and then vanished in separate observations taken years apart. On the final pass there were no magic islands to be seen. The radar team is still working to understand what the features might have been, with leading candidates being bubbles or waves.

Most interesting to the radar team was a set of observations that was both the first and last of its kind, in which the instrument was used to sound the depths of several of the small lakes that dot Titan's north polar region. Going forward, the researchers will be working to tease out information from these data about the lakes' composition, in terms of methane versus ethane.

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First mutant ants shed light on evolution of social behavior

Ants detect pheromones though porous hairs on their antennae. The researchers generated mutants lacking this ability.

Ants run a tight ship. They organize themselves into groups with very specific tasks: foraging for food, defending against predators, building tunnels, etc. An enormous amount of coordination and communication is required to accomplish this.

To explore the evolutionary roots of the remarkable system, researchers at The Rockefeller University have created the first genetically altered ants, modifying a gene essential for sensing the pheromones that ants use to communicate. The result, severe deficiencies in the ants' social behaviors and their ability to survive within a colony, both sheds light on a key facet of social evolution and demonstrates the feasibility and utility of genome editing in ants.

"It was well known that ant language is produced through pheromones, but now we understand a lot more about how pheromones are perceived," says Daniel Kronauer, head of the Laboratory of Social Evolution and Behavior. "The way ants interact is fundamentally different from how solitary organisms interact, and with these findings we know a bit more about the genetic evolution that enabled ants to create structured societies."

Social beginnings

The most important class of pheromones in ant communication are hydrocarbons, which can communicate species, colony, and caste identity as well as reproductive status. These pheromone signals are detected by porous sensory hairs on the ants' antennae that contain what are called odorant receptors -- proteins that recognize specific chemicals and pass the signal up to the brain.

Work in the Kronauer lab, led by graduate student Sean McKenzie and published in the Proceedings of the National Academy of Sciences, has shown that a group of odorant receptor genes, known as 9-exon-alpha ORs, are responsible for sensing hydrocarbons in the clonal raider ant species Ooceraea biroi.

McKenzie and his colleagues also examined the genomes of related insects to determine where 9-exon ORs emerged in the evolution of this species, and found that there was an enormous duplication in this gene in a relatively short evolutionary timescale: While the ancestors of bees and ants only had one to three copies of this gene, clonal raider ants have about 180 copies. The massive expansion of 9-exon ORs happened concurrently with the evolution of complex social behavior, suggesting that the duplication of odorant receptor genes was vital to the development of ant communication.

Communication interrupted

To further dissect the role of odorant receptors in ant communication and social behavior, the Kronauer lab disrupted a gene called orco, required for the function of all odorant receptors. Introducing the mutation -- using a genetic manipulation technique known as CRISPR -- was easy. The challenge was keeping the mutant ants alive.

"We had to convince the colonies to accept the mutants. If the conditions weren't right, the worker ants would stop caring for larvae and destroy them," says graduate fellow Waring Trible, who led this portion of the study, published separately in Cell. "Once the ants successfully made it to the adult phase, we noticed a shift in their behavior almost immediately."

Ants typically travel single-file, sensing the route by detecting pheromones left by the ants in front. Using an automated system that tracks color-coded ants and an algorithm that analyzes movement, the researchers observed that, among other behavioral abnormalities, the mutant ants couldn't fall in line. The finding suggests that the missing odorant receptors are crucial for pheromone detection, and therefore social organization.

The lack of odorant receptors also changed the shape of the ants' brains. This was a surprise, says Trible, "because brain anatomy is not affected in orco mutants in other insects, like the fruit fly. Our findings suggest that ants are fundamentally different -- they need functional odorant receptors for the brain to develop correctly. This points to how crucial sensing odors is to ants, an ability that may be less important in other insects."

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Cardiac stem cells from young hearts could rejuvenate old hearts

Telomeres, stained in purple, are caps which protect our chromosomes from damage. They get shorter with aging and are enlarged with young CDCs in the study.

Cardiac stem cell infusions could someday help reverse the aging process in the human heart, making older ones behave younger, according to a new study from the Cedars-Sinai Heart Institute.

"Our previous lab studies and human clinical trials have shown promise in treating heart failure using cardiac stem cell infusions," said Eduardo Marbán, MD, PhD, director of the Cedars-Sinai Heart Institute and the primary investigator of the study. "Now we find that these specialized stem cells could turn out to reverse problems associated with aging of the heart."

The study was published today by the European Heart Journal.

In the study, investigators injected cardiosphere-derived cells, a specific type of stem cell, from newborn laboratory rats into the hearts of rats with an average age of 22 months, which is considered aged. Other laboratory rats from the same age group were assigned to receive placebo treatment, saline injections instead of stem cells. Both groups of aged rats were compared to a group of young rats with an average age of 4 months.

Baseline heart function was measured in all rats, using echocardiograms, treadmill stress tests and blood analysis. The group of older rats underwent an additional round of testing one month after receiving cardiosphere-derived cells that came from young rats.

"The way the cells work to reverse aging is fascinating," Marbán said. "They secrete tiny vesicles that are chock-full of signaling molecules such as RNA and proteins. The vesicles from young cells appear to contain all the needed instructions to turn back the clock."

Results of those tests show lab rats that received the cardiosphere-derived cells:

• Experienced improved heart function
• Demonstrated longer heart cell telomeres, compound structures located at the ends of chromosomes that shrink with age
• Improved their exercise capacity by an average of approximately 20 percent
• Regrew hair faster than rats that didn't receive the cells

"This study didn't measure whether receiving the cardiosphere-derived cells extended lifespans, so we have a lot more work to do," said Lilian Grigorian-Shamagian, MD, PhD, co-primary investigator and the first author of the study. "We have much to study, including whether CDCs need to come from a young donor to have the same rejuvenating effects and whether the extracellular vesicles are able to reproduce all the rejuvenating effects we detect with CDCs."

Since Marbán's team completed the world's first cardiac stem cell infusion in 2009, the Cedars-Sinai Heart Institute has made significant contributions to decoding and understanding how cardiac stem cells regenerate damaged heart muscle. The team is studying the use of stem cells to treat patients with Duchenne muscular dystrophy as well as patients with heart failure with preserved ejection fraction, a condition that affects more than 50 percent of all heart failure patients.

General support for Marbán's laboratory is provided by the National Institutes of Health. The CDCs, manufactured by Capricor Inc. (NASDAQ: CAPR) as their product CAP-1002, have been used in other human clinical trials.

The process to grow cardiac-derived stem cells was developed by Marbán when he was on the faculty of Johns Hopkins University and further developed at Cedars-Sinai. Capricor has licensed the process from Johns Hopkins and from Cedars-Sinai for clinical and commercial development. Capricor has licensed additional intellectual property from Cedars-Sinai and the University of Rome. Cedars-Sinai and Marbán have financial interests in Capricor.

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New plate adds plot twist to ancient tectonic tale

Misfit plates in the Pacific led Rice University scientists to the discovery of the Malpelo Plate between the Galapagos Islands and the South American coast.

A microplate discovered off the west coast of Ecuador adds another piece to Earth's tectonic puzzle, according to Rice University scientists.

Researchers led by Rice geophysicist Richard Gordon discovered the microplate, which they have named "Malpelo," while analyzing the junction of three other plates in the eastern Pacific Ocean.

The Malpelo Plate, named for an island and an underwater ridge it contains, is the 57th plate to be discovered and the first in nearly a decade, they said. They are sure there are more to be found.

The research by Gordon, lead author Tuo Zhang and co-authors Jay Mishra and Chengzu Wang, all of Rice, appears in Geophysical Research Letters.

How do geologists discover a plate? In this case, they carefully studied the movements of other plates and their evolving relationships to one another as the plates move at a rate of millimeters to centimeters per year.

The Pacific lithospheric plate that roughly defines the volcanic Ring of Fire is one of about 10 major rigid tectonic plates that float and move atop Earth's mantle, which behaves like a fluid over geologic time. Interactions at the edges of the moving plates account for most earthquakes experienced on the planet. There are many small plates that fill the gaps between the big ones, and the Pacific Plate meets two of those smaller plates, the Cocos and Nazca, west of the Galapagos Islands.

One way to judge how plates move is to study plate-motion circuits, which quantify how the rotation speed of each object in a group (its angular velocity) affects all the others. Rates of seafloor spreading determined from marine magnetic anomalies combined with the angles at which the plates slide by each other over time tells scientists how fast the plates are turning.

"When you add up the angular velocities of these three plates, they ought to sum to zero," Gordon said. "In this case, the velocity doesn't sum to zero at all. It sums to 15 millimeters a year, which is huge."

That made the Pacific-Cocos-Nazca circuit a misfit, which meant at least one other plate in the vicinity had to make up the difference. Misfits are a cause for concern -- and a clue.

Knowing the numbers were amiss, the researchers drew upon a Columbia University database of extensive multibeam sonar soundings west of Ecuador and Colombia to identify a previously unknown plate boundary between the Galapagos Islands and the coast.

Previous researchers had assumed most of the region east of the known Panama transform fault was part of the Nazca plate, but the Rice researchers determined it moves independently. "If this is moving in a different direction, then this is not the Nazca plate," Gordon said. "We realized this is a different plate and it's moving relative to the Nazca."

Evidence for the Malpelo plate came with the researchers' identification of a diffuse plate boundary that runs from the Panama Transform Fault eastward to where the diffuse plate boundary intersects a deep oceanic trench just offshore of Ecuador and Colombia.

"A diffuse boundary is best described as a series of many small, hard-to-spot faults rather than a ridge or transform fault that sharply defines the boundary of two plates," Gordon said. "Because earthquakes along diffuse boundaries tend to be small and less frequent than along transform faults, there was little information in the seismic record to indicate this one's presence."

"With the Malpelo accounted for, the new circuit still doesn't close to zero and the shrinking Pacific Plate isn't enough to account for the difference either," Zhang said. "The nonclosure around this triple junction goes down -- not to zero, but only to 10 or 11 millimeters a year.

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New class of chemical reaction discovered

A chemical reaction where three different molecules (e.g. H, O2, H) each participate in the breaking and forming of chemical bonds. The reaction is mediated by an ephemeral collision complex (HO2**) formed from the collision of two molecules (H, O2) which then reacts upon colliding with a third molecule (H). Data from advanced computations reveal that reactions of this class, hypothesized nearly a century ago and then later assumed to be unimportant, are major chemical pathways.

A new study led by Michael P. Burke, assistant professor of mechanical engineering at Columbia Engineering, has identified the significance of a new class of chemical reactions involving three molecules that each participate in the breaking and forming of chemical bonds. The reaction of three different molecules is enabled by an "ephemeral collision complex," formed from the collision of two molecules, which lives long enough to collide with a third molecule.

This fourth class, which the researchers have named "chemically termolecular reactions," was first hypothesized by Cyril Hinshelwood and Nikolay Semenov in their studies of chain reactions in the 1920s and 30s (they won the 1956 Nobel Prize in Chemistry for this work). For decades, researchers have considered these reactions unimportant -- if they even occurred at all -- and until now, no one has studied them. Burke, who explores a variety of problems at the interface between fundamental physical chemistry and practical engineering devices, decided to investigate these reactions after realizing that common combustion situations, such as those encountered in many engines, have sufficiently high fractions of highly reactive molecules known as free radicals to make these reactions possible. The new study is published today in Nature Chemistry.

"Combustion has always been a launching point for understanding all sorts of other chemical mechanisms," says Burke, who is also a member of the Data Science Institute. "Potentially there could be innumerable reactions from this new class that impact how we model gas phase chemistry, from designing new types of engines to understanding the planetary chemistry responsible for cloud formations, climate change, evolution of pollutants, even perhaps the sequence of reactions that could impact the conditions for extraterrestrial life. Our discovery opens up a whole new world of possibilities."

For example, space vehicles experience very high temperatures and radical fractions in their descent back to Earth. Burke speculates that this fourth class of reactions could impact the heat flux to the vehicle, with significant implications for the design of thermal protection systems to keep astronauts and/or payloads safe when coming down to Earth.

Working with Stephen J. Klippenstein, (Chemical Sciences and Engineering Division, Argonne National Laboratory), Burke used state-of-the-art computational methods, combining quantum chemical computations that simulate the breaking and forming of chemical bonds among reacting molecules with kinetic-transport computations that simulate the reactions and movements of bulk gases that governs performance of engineering devices.

"The power of these state-of-the-art computational methods," says Burke, "is that they can provide a unique lens into harsh chemical environments ill-suited for experimental techniques for studying individual reaction dynamics. Our calculations are based on computational data produced from first principles: the Schrödinger equation, the fundamental equation of quantum mechanics. Combining these data with other physics-based models enables us to directly pinpoint the impact of just a single reaction out of many, in a way that is very difficult to do in the lab."

Using theoretical methods, including those they developed for this study, the researchers showed that these chemically termolecular (i.e. three-molecule) reactions not only are major chemical pathways but also impact flame propagation speeds, a measure of overall fuel reactivity that governs the performance, stability, and efficiency of many modern engines.

The chemistry of many systems, including combustion and planetary atmospheres, is governed by complex chemical mechanisms, where the overall conversion from a set of initial reactants to a set of final products goes though many intermediate chemical molecules with many individual chemical reactions occurring on the molecular level. Our current understanding of the complex mechanisms of combustion and planetary atmospheres has been premised on the classes of reactions that are known to take place. Up to now, only three classes of reactions have been considered:

• Unimolecular reactions, where one reactant undergoes bond breaking and/or forming to yield different products
• Bimolecular reactions, where two reactants collide and then undergo bond breaking and/or forming to yield different products
• Termolecular association reactions, where two reactants collide to form a molecular complex with a new chemical bond between the two reactants and a third molecule, known as the bath gas, removes some of the internal kinetic energy of that molecule to stabilize it

The bath gas is usually considered an inert, or non-reactive, molecule that does not participate in any bond breaking or forming, but instead takes away some energy from the other molecular complex (which would have enough internal kinetic energy to decompose spontaneously if no energy were taken away).

If instead the molecular complex collides with a reactive molecule, then the third molecule can participate in the bond-breaking/forming process, yielding what Burke and Klippenstein call a "chemically termolecular reaction" product. "In our paper, we showed the importance of reactions involving H + O2 complexes with other radical species, e.g. H + O2 + H, in combustion environments," he notes. "However, given the fact that reactive molecules, like free radicals and molecular oxygen, are major constituents in combustion and certain planetary environments, there is significant potential for other chemically termolecular reactions to occur and to play a significant role in other environments."

William H. Green, professor of chemical engineering at MIT, says of the study, "It has long been known that many gas phase association reactions have very low effective rates, because the initial energized adduct does not live long enough to be stabilized by collisional energy transfer, and just falls apart back to the reactants. This has led the field to think that these transitory adducts can be completely ignored. This article reveals that even if the unimolecular reactions of energized adducts are negligible, they can still participate in bimolecular reactions, with surprisingly important consequences."

Read more at Science Daily

Prehistoric Brits Ate People and Then Turned Their Bones Into Art

Engraved artifacts from Gough’s Cave.

Cheddar Gorge and nearby areas of Somerset in England are world famous for their cheddar cheeses, many of which are aged in caves. But Gough’s Cave, located in the gorge, is also famous for something else entirely: cannibalism.

One of the most extensive assemblages of human bones showing evidence for cannibalism was found in the cave over the course of multiple excavations.

A bone from the assemblage, a right radius (forearm), has zig-zag marks on one side. New research on the marks, published in the journal PLOS ONE, concludes that they are engravings, which were likely incised on the bone by whomever consumed the flesh of the person around 14,700 years ago.

The discovery follows prior analysis in 2011 of human skulls of the same age from the cave. Lead author Silvia Bello and colleagues Simon Parfitt and Chris Stringer, all from the Natural History Museum in London, determined that the skulls were “scrupulously cleaned” of soft tissues and otherwise modified to produce cups.

Taken together, “the remains have provided unequivocal evidence that the bodies were eaten, but the shaping of the skulls into skull cups and the engraving of the radius strongly suggest that this act [cannibalism] wasn’t for nutritional and survival reasons only, but it retains some ritualistic connotations,” said Bello, who is the lead author of the new paper by the same team, which includes another colleague from the museum, Rosalind Wallduck.

An engraved kapala.

“None of the remains seem to reveal any obvious signs of trauma,” Bello added, “suggesting that the ‘consumed’ probably died of natural causes rather than a violent death. If this is the case, it is probable that the consumers and the consumed belonged to the same group.”

The practice might then have been endocannibalism, which refers to eating the flesh of a person — usually in a mortuary context — after the individual has died.

Different forms of endocannibalism have occurred around the world. The Amahuaca tribe of Peru, for example, would grind human bones with corn, mix them with liquid, and drink the resulting gruel.

In India, members of the Aghori religious sect still use bones from human corpses to craft skull cups, known as kapalas. Early Tibetan kapalas have been found with elaborate carvings on them, or mounted with precious metals and jewels.

The prehistoric people of Gough’s Cave were nomadic hunter-gatherers who lived off the land.

“The climate warmed up suddenly about 15,000 years ago, and was nearly as warm as today in the UK, with animals like horse and red deer around, and on the menu,” Stringer said. “There is also evidence of worked mammoth ivory at the site, indicating that these groups traveled into colder regions as well, utilizing old tusks lying on the landscape, or maybe even keeping such materials over several generations.”

The skull cups and engraved arm bone were certainly long-lasting items too, showing how such natural materials can remain intact over long periods under certain conditions.

A chamber and mirror pool inside Gough’s Cave.

There doesn’t appear to be a connection between the prehistoric Brits and the other global practitioners of endocannibalism. Evidence for cannibalism among Neanderthals dating to early periods has also been found, but again, the researchers do not believe that there was a connection to the activities of Gough’s Cave.

“These Gough’s people were separated by more than 20,000 years from the last Neanderthals and the first modern-looking humans in Europe, so it’s unlikely to be the continuity of a tradition,” Stringer explained. “I think these traditions probably developed independently of each other.”

The zig-zag design was a common one for the period. Bello shared that several lissoirs — bone tools used to smooth hides — from sites dated to the Magdalenian period (17,000–12,000 years ago) in France are engraved with similar artistic motifs.

The researchers believe that the arm bone engraving was meaningful, though, beyond a familiar and presumably easily-produced design.

“The act of engraving has often been associated with ways of remembering events, places or circumstances — a sort of extension of our memory outside our body,” Bello said. “In this case, however, the engraving of this bone may have been a sort of memory more directly related to the deceased, and an intrinsic part of the cannibalistic ritual itself.”

Read more at Seeker