Feb 2, 2019

Huge cavity in Antarctic glacier signals rapid decay

Thwaites Glacier.
A gigantic cavity -- two-thirds the area of Manhattan and almost 1,000 feet (300 meters) tall -- growing at the bottom of Thwaites Glacier in West Antarctica is one of several disturbing discoveries reported in a new NASA-led study of the disintegrating glacier. The findings highlight the need for detailed observations of Antarctic glaciers' undersides in calculating how fast global sea levels will rise in response to climate change.

Researchers expected to find some gaps between ice and bedrock at Thwaites' bottom where ocean water could flow in and melt the glacier from below. The size and explosive growth rate of the newfound hole, however, surprised them. It's big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years.

"We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it," said Eric Rignot of the University of California, Irvine, and NASA's Jet Propulsion Laboratory in Pasadena, California. Rignot is a co-author of the new study, which was published in Science Advances. "Thanks to a new generation of satellites, we can finally see the detail," he said.

The cavity was revealed by ice-penetrating radar in NASA's Operation IceBridge, an airborne campaign beginning in 2010 that studies connections between the polar regions and the global climate. The researchers also used data from a constellation of Italian and German spaceborne synthetic aperture radars. These very high-resolution data can be processed by a technique called radar interferometry to reveal how the ground surface below has moved between images.

"[The size of] a cavity under a glacier plays an important role in melting," said the study's lead author, Pietro Milillo of JPL. "As more heat and water get under the glacier, it melts faster."

Numerical models of ice sheets use a fixed shape to represent a cavity under the ice, rather than allowing the cavity to change and grow. The new discovery implies that this limitation most likely causes those models to underestimate how fast Thwaites is losing ice.

About the size of Florida, Thwaites Glacier is currently responsible for approximately 4 percent of global sea level rise. It holds enough ice to raise the world ocean a little over 2 feet (65 centimeters) and backstops neighboring glaciers that would raise sea levels an additional 8 feet (2.4 meters) if all the ice were lost.

Thwaites is one of the hardest places to reach on Earth, but it is about to become better known than ever before. The U.S. National Science Foundation and British National Environmental Research Council are mounting a five-year field project to answer the most critical questions about its processes and features. The International Thwaites Glacier Collaboration will begin its field experiments in the Southern Hemisphere summer of 2019-20.

How Scientists Measure Ice Loss

There's no way to monitor Antarctic glaciers from ground level over the long term. Instead, scientists use satellite or airborne instrument data to observe features that change as a glacier melts, such as its flow speed and surface height.

Another changing feature is a glacier's grounding line -- the place near the edge of the continent where it lifts off its bed and starts to float on seawater. Many Antarctic glaciers extend for miles beyond their grounding lines, floating out over the open ocean.

Just as a grounded boat can float again when the weight of its cargo is removed, a glacier that loses ice weight can float over land where it used to stick. When this happens, the grounding line retreats inland. That exposes more of a glacier's underside to sea water, increasing the likelihood its melt rate will accelerate.

An Irregular Retreat

For Thwaites, "We are discovering different mechanisms of retreat," Millilo said. Different processes at various parts of the 100-mile-long (160-kilometer-long) front of the glacier are putting the rates of grounding-line retreat and of ice loss out of sync.

The huge cavity is under the main trunk of the glacier on its western side -- the side farther from the West Antarctic Peninsula. In this region, as the tide rises and falls, the grounding line retreats and advances across a zone of about 2 to 3 miles (3 to 5 kilometers). The glacier has been coming unstuck from a ridge in the bedrock at a steady rate of about 0.4 to 0.5 miles (0.6 to 0.8 kilometers) a year since 1992. Despite this stable rate of grounding-line retreat, the melt rate on this side of the glacier is extremely high.

"On the eastern side of the glacier, the grounding-line retreat proceeds through small channels, maybe a kilometer wide, like fingers reaching beneath the glacier to melt it from below," Milillo said. In that region, the rate of grounding-line retreat doubled from about 0.4 miles (0.6 kilometers) a year from 1992 to 2011 to 0.8 miles (1.2 kilometers) a year from 2011 to 2017. Even with this accelerating retreat, however, melt rates on this side of the glacier are lower than on the western side.

These results highlight that ice-ocean interactions are more complex than previously understood.

Milillo hopes the new results will be useful for the International Thwaites Glacier Collaboration researchers as they prepare for their fieldwork. "Such data is essential for field parties to focus on areas where the action is, because the grounding line is retreating rapidly with complex spatial patterns," he said.

"Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades," Rignot said.

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How predatory plankton created modern ecosystems after 'Snowball Earth'

Grand Canyon (stock image). Max Planck researchers found 635 million year-old molecules in rock samples from the Grand Canyon, most likely from predatory plankton. The microorganisms probably prepared the soil for today's ecosystems after the earth thawed again after a phase of complete glaciation.
Around 635 to 720 million years ago, during Earth's most severe glacial period, Earth was twice almost completely covered by ice, according to current hypotheses. The question of how life survived these 'Snowball Earth' glaciations, lasting up to about 50 million years, has puzzled scientists for many decades. An international team, led by Dutch and German researchers of the Max Planck Society, now found the first detailed glimpse of life after the 'Snowball' in the form of newly discovered ancient molecules, buried in old rocks.

"All higher animal life forms, including us humans, produce cholesterol. Algae and bacteria produce their own characteristic fat molecules," says first author Lennart van Maldegem from Max Planck Institute (MPI) for Biogeochemistry, who recently moved to the Australian National University in Canberra, Australia. "Such fat molecules can survive in rocks for millions of years, as the oldest (chemical) remnants of organisms, and tell us now what type of life thrived in the former oceans long ago."

But the fossil fats the researchers recently discovered in Brazilian rocks, deposited just after the last Snowball glaciation, were not what they suspected. "Absolutely not," says team-leader Christian Hallmann from MPI for Biogeochemistry. "We were completely puzzled, because these molecules looked quite different from what we've ever seen before!"

Using sophisticated separation techniques, the team managed to purify minuscule amounts of the mysterious molecule and identify its structure by nuclear magnetic resonance in the NMR department of Christian Griesinger at Max Planck Institute for Biophysical Chemistry. "This is highly remarkable itself," according to Klaus Wolkenstein from MPI for Biophysical Chemistry and the Geoscience Centre of the University of Göttingen. "Never has a structure been elucidated with such a small amount of such an old molecule." The structure was chemically identified as 25,28-bisnorgammacerane -- abbreviated as BNG, as van Maldegem suggests.

Fossil fats most likely from heterotropic plankton

Yet the origin of the compound remained enigmatic. "We of course looked if we could find it elsewhere," says van Maldegem, who then studied hundreds of ancient rock samples, with rather surprising success. "In particular the Grand Canyon rocks really were an eye-opener," says Hallmann. Although nowadays mostly sweltering hot, these rocks had also been buried under kilometres of glacial ice around 700 million years ago. Detailed additional analyses of molecules in Grand Canyon rocks -- including presumed BNG-precursors, the distribution of steroids and stable carbon isotopic patterns -- led the authors to conclude that the new BNG molecule most likely derives from heterotrophic plankton, marine microbes that rely on consuming other organisms for gaining energy. "Unlike for example green algae that engage in photosynthesis and thus belong to autotrophic organisms, these heterotrophic microorganisms were true predators that gained energy by hunting and devouring other algae and bacteria," according to van Maldegem.

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Feb 1, 2019

Ancient pandas weren't exclusive bamboo eaters, bone evidence suggests

This image shows a wild Giant Panda in Foping Nature Reserve, feeding on bamboo.
The giant pandas we know and love today live only in the understory of particular mountains in southwestern China, where they subsist on bamboo alone. In support of their tough and fibrous bamboo diet, they've got distinctive teeth, skull, and muscle characteristics along with a special pseudo-thumb, the better to grasp and hold bamboo stems, leaves, and shoots with. But according to new evidence reported in Current Biology on January 31, extinct and ancient panda species most likely had a more varied and complex diet.

"It has been widely accepted that giant pandas have exclusively fed on bamboo for the last two million years," says Fuwen Wei of Chinese Academy of Sciences. But, "our results showed the opposite."

It's impossible to know exactly what extinct animals ate. But researchers can get clues by analyzing the composition of stable isotopes (different forms of the same element that contain equal numbers of protons but different numbers of neutrons) in animal teeth, hair, and bones, including fossil remains. In the new study, the researchers first analyzed bone collagen of modern pandas (1970s-2000s) and other mammals from the same mountains.

The stable isotopic composition of carbon and nitrogen from modern panda and other modern mammal bone samples indicated three obvious groups: carnivores, herbivores, and giant pandas. The giant pandas were clearly unique, on account of their habit of eating bamboo. Next, Wei's team measured bone collagen isotopes of 12 ancient pandas collected from seven archaeological sites in southern and southwestern China and compared them to the patterns they observed in modern giant pandas.

The data comparison showed that ancient and modern pandas are isotopically distinct from one another, suggesting differences in their dietary habits. There was also more variation among ancient panda species, suggesting that the niche they occupied was about three times wider than that of modern pandas. That is, ancient pandas most likely had a varied diet, similar to that of other mammalian species that lived alongside them. They were, the researchers write, "probably not exclusive bamboo feeders."

The researchers suggest that pandas' dietary habits have evolved in two phases. First, the pandas went from being meat eaters or omnivores to becoming dedicated plant eaters. Only later did they specialize on bamboo.

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Psychologists solve mystery of songbird learning

A male zebra finch watches a video monitor displaying a female finch performing an arousal behavior called a 'fluff-up.'
Scientists rely on animal models to gain insight into how humans learn language, but it turns out that one of their favorite models, the zebra finch, has been entirely misunderstood.

New research reveals that these birds don't simply learn their songs by imitating adults: They learn by watching their mothers' reactions to their immature songs.

In "Female Social Feedback Reveals Non-Imitative Mechanisms of Vocal Learning in Zebra Finches," published Jan. 31 in Current Biology, co-authors Michael Goldstein, associate professor of psychology, and doctoral candidate Samantha Carouso-Peck solve the mystery of why juvenile male zebra finches learn to sing better when females are around, even though the females don't sing.

The researchers found that the adult females guide juveniles' song development through specific interactions, similar to how human babies learn to talk. This study brings the number of species known to engage in socially guided vocal learning to four: zebra finches, humans, marmosets and cowbirds.

The researchers' clue to the zebra finch mystery came when they considered that birds see the world at several times the "critical flicker fusion rate" of humans. Simply put, birds can perceive events that happen much too fast for a human to see, and most previous research on social learning has not taken into account such rapid "bird time," in which tiny behaviors can have large social effects.

Using slowed-down video, the Cornell researchers were able to identify tiny movements, imperceptible to the human eye, made by the female zebra finches to encourage the baby songbirds. These included wing gestures and "fluff-ups," an arousal behavior in which the bird fluffs up its feathers.

"Over time, the female guides the baby's song toward her favorite version. There's nothing imitative about it," said Carouso-Peck.

The study included nine pairs of zebra finches, genetic brothers raised for the first 35 days by their respective parents. When they reached the age at which they begin to produce practice song (subsong), the siblings were split up, moved into individual soundproof containers and randomly assigned to one of two conditions: "contingent" or "yoked."

Contingent birds were monitored by Carouso-Peck, and each time they sang in a way that matched their fathers' song, she triggered a video playback of a female performing a fluff-up. The yoked bird saw the same fluff-up video at the same time as his contingent brother, but from his perspective the fluff-ups happened at random times unrelated to his song production.

After the birds' songs "crystallized" into the final version, the researchers compared them to the songs of the juveniles' fathers. They found that the birds in the contingent group learned significantly more accurate songs than their yoked brothers. Had the traditional model of song learning as pure imitation been correct, both birds would have learned the same song, because they had the same opportunity to memorize it early and practice it, according to Goldstein.

One possible reason for the zebra finch learning style, according to the researchers, is that because zebra finches use their songs to attract mates rather than defend territory, integrating female preferences into song is "a highly adaptive strategy for future reproductive success," they wrote.

"Historically we've been studying these birds in isolation. That means we've been missing out on the entire social aspect of song learning," Goldstein said.

Similarly, he said, most labs study human babies more or less in isolation.

"But what babies -- zebra finch or human -- are good at is exploiting social information in their environment," Goldstein said. "These immature behaviors are not mindless practice and noise. Their function is to motivate the adults in the room to provide information."

Zebra finches are widely used in research of vocal learning and production as well as research on Parkinson's disease, autism, stuttering and genetic disorders of speech. "Incorporating social factors into studies of zebra finch learning will strengthen the species as a model system," the paper's authors write, "as it will uncover new possibilities for drawing parallels with human speech acquisition."

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Membraneless protocells could provide clues to formation of early life

Membraneless protocells -- called complex coacervates -- can bring together molecules of RNA allowing the RNAs to perform certain reactions, an important step in the origin of life on Earth. The Image shows droplets of complex coacervates as seen under a microscope. The inset shows RNA molecules (cyan) are highly concentrated inside the droplets compared to the surrounding (dark). At roughly 2-5 micrometers in diameter, the droplets are about 14-35 times thinner than human hair.
Membraneless assemblies of positively- and negatively-charged molecules can bring together RNA molecules in dense liquid droplets, allowing the RNAs to participate in fundamental chemical reactions. These assemblies, called "complex coacervates," also enhance the ability of some RNA molecules themselves to act as enzymes -- molecules that drive chemical reactions. They do this by concentrating the RNA enzymes, their substrates, and other molecules required for the reaction. The results of testing and observation of these coacervates provide clues to reconstructing some of the early steps required for the origin of life on Earth in what is referred to as the prebiotic "RNA world." A paper describing the research, by scientists at Penn State, appears January 30, 2019 in the journal Nature Communications.

"We're interested in how you go from a world with no life to one with life," said Philip C. Bevilacqua, Distinguished Professor of Chemistry and of Biochemistry and Molecular Biology at Penn State and one of the senior authors of the paper. "One can imagine a lot of steps in this process, but we are not looking at the most elemental steps. We are interested in a slightly later step, to see how RNA molecules could form from their basic building blocks and if those RNA molecules could drive the reactions needed for life in the absence of proteins."

Life as we know it today generally requires genetic material -- DNA, which is first transcribed into RNA. These two molecules carry information for the production of proteins, which are in turn required for most functional aspects of life, including the production of new genetic material. This sets up a "chicken and the egg" dilemma for the origins of life on early Earth. DNA is required to produce proteins, but proteins are required to produce DNA.

"RNA -- or something similar -- has been thought of as a key to solving this dilemma," said Raghav R. Poudyal, Simons Origins of Life Postdoctoral Fellow at Penn State and first author of the paper. "RNA molecules carry genetic information, but they can also function as enzymes to catalyze the chemical reactions needed for early life. This fact has led to the notion that life on Earth went through a stage where RNA played an active role in facilitating chemical reactions -- "the RNA World" -- where self-replicating RNA molecules both carried the genetic information and performed functions that are now generally carried out by proteins."

Another common feature of life on Earth is that it is compartmentalized in cells, often with an outer membrane, or in smaller compartments inside cells. These compartments ensure that all the components for the chemical reactions of life are in easy reach, but in the prebiotic world the building blocks for RNA -- or the RNA enzymes needed to drive the chemical reactions that could lead to life -- would probably have been scarce, floating around in the primordial soup.

"You can think of these RNA enzymes like a car being produced in an assembly line," said Poudyal. "If you don't have the parts in the right place in the factory, the assembly line doesn't work. Without coacervates, the parts needed for chemical reactions are too dilute and are unlikely to find each other, but inside the coacervates, all the parts that the enzyme needs to work are nearby."

The researchers therefore looked at a variety of materials that may have existed in the pre-life Earth that can form coacervates -- membraneless protocells -- and then allowed critical functions like sequestering the building blocks of RNA and bringing together RNA enzymes and their targets.

"It was previously known that RNA molecules can assemble and elongate in solutions with high concentrations of magnesium," said Poudyal. "Our work shows that coacervates made from certain materials allow this non-enzymatic template-mediated RNA assembly to occur even in the absence of magnesium."

The coacervates are composed of positively charged molecules called polyamines and negatively charged polymers which cluster together to form membraneless compartments in a solution. Negatively charged RNA molecules are also attracted to the polyamines in the coacervates. Within the coacervates the RNA molecules are as much as 4000 times more concentrated than in the surrounding solution. By concentrating the RNA molecules in the coacervates, RNA enzymes are more likely to find their targets to drive chemical reactions.

"Although all the polyamines we tested were able to participate in formation of RNA-rich droplets, they differed in their ability to support RNA elongation," said Christine Keating, professor of chemistry at Penn State and a senior author on the paper. "These observations help us understand how the chemical environment within different membraneless compartments can impact RNA reactions."

"Although we can't look back to see the exact steps taken to form the first life on Earth, coacervates like the ones we can create in the laboratory may have helped by facilitating chemical reactions that otherwise would not have been possible," said Poudyal.

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Hubble fortuitously discovers a new galaxy in the cosmic neighborhood

This composite image shows the location of the accidentally discovered dwarf galaxy Bedin 1 behind the globular cluster NGC 6752. The lower image, depicting the complete cluster, is a ground-based observation from the Digitized Sky Survey 2. The upper right image shows the full field of view of the NASA/ESA Hubble Space Telescope. The upper left one highlights the part containing the galaxy Bedin 1.
Astronomers using the NASA/ESA Hubble Space Telescope to study some of the oldest and faintest stars in the globular cluster NGC 6752 have made an unexpected finding. They discovered a dwarf galaxy in our cosmic backyard, only 30 million light-years away. The finding is reported in the journal Monthly Notices of the Royal Astronomical Society: Letters.

An international team of astronomers recently used the NASA/ESA Hubble Space Telescope to study white dwarf stars within the globular cluster NGC 6752. The aim of their observations was to use these stars to measure the age of the globular cluster, but in the process they made an unexpected discovery.

In the outer fringes of the area observed with Hubble's Advanced Camera for Surveys a compact collection of stars was visible. After a careful analysis of their brightnesses and temperatures, the astronomers concluded that these stars did not belong to the cluster -- which is part of the Milky Way -- but rather they are millions of light-years more distant.

Our newly discovered cosmic neighbour, nicknamed Bedin 1 by the astronomers, is a modestly sized, elongated galaxy. It measures only around 3000 light-years at its greatest extent -- a fraction of the size of the Milky Way. Not only is it tiny, but it is also incredibly faint. These properties led astronomers to classify it as a dwarf spheroidal galaxy.

Dwarf spheroidal galaxies are defined by their small size, low-luminosity, lack of dust and old stellar populations. 36 galaxies of this type are already known to exist in the Local Group of Galaxies, 22 of which are satellite galaxies of the Milky Way.

While dwarf spheroidal galaxies are not uncommon, Bedin 1 has some notable features. Not only is it one of just a few dwarf spheroidals that have a well established distance but it is also extremely isolated. It lies about 30 million light-years from the Milky Way and 2 million light-years from the nearest plausible large galaxy host, NGC 6744. This makes it possibly the most isolated small dwarf galaxy discovered to date.

From the properties of its stars, astronomers were able to infer that the galaxy is around 13 billion years old -- nearly as old as the Universe itself. Because of its isolation -- which resulted in hardly any interaction with other galaxies -- and its age, Bedin 1 is the astronomical equivalent of a living fossil from the early Universe.

Read more at Science Daily

Jan 31, 2019

How the fruit fly got its stripes

A team at Princeton found that cells optimize the use of information available to them to find their correct placement during fly embryo development. Information deposited in the embryo by the fly mother is translated into genetic and molecular instructions that drive the precise placement of stripes on the developing fly larva.
The first moments of life unfold with incredible precision. Now, using mathematical tools and the help of fruit flies, researchers at Princeton have uncovered new findings about the mechanisms behind this precision.

In a new study published in the journal Cell, the team showed that cells determine exactly where they need to be and therefore what body parts they will become by optimizing the use of all information available from the genetic code. This optimization allows each cell to position itself within one cell's width of where it should be, rather than making errors that later are corrected.

The study also demonstrates that a complex biological system can operate according to a mathematically optimal process. The team was able to predict the placement of cells to within 1 percent of their actual locations along the length of the embryo, showing that biological behaviors can be computed and predicted from theoretical principles.

"The information required to specify precise cell locations -- and therefore what body parts they will become -- is present and utilized at the earliest stages of development in fruit flies," said Thomas Gregor, associate professor of physics and the Lewis-Sigler Institute for Integrative Genomics. "This contrasts with the prevailing view that the position of the cells is refined slowly over time."

"The theoretical idea is very simple, which is that every cell is using all the information that it can squeeze out of the relevant genes," said William Bialek, the John Archibald Wheeler/Battelle Professor in Physics and the Lewis-Sigler Institute for Integrative Genomics. "Something we've known for a while, but never stop being amazed by, is that the whole system is incredibly precise, and this fact is what spurred us to believe that the cells are using all the information that they can."

Cells take cues from genes, or more specifically, from the protein molecules that those genes produce. But do the cells use all of the information to get everything right the first time? Or is the system messy, with mistakes that are repaired before irreparable harm is done to the embryo?

The question was exactly the type of big-picture problem that the team of biologists and physicists, who have been working together since the early 2000s, likes to tackle.

Thanks to previous work by team member Eric Wieschaus, the Squibb Professor in Molecular Biology and professor of molecular biology and the Lewis-Sigler Institute for Integrative Genomics, scientists know exactly which genes and molecules are involved in creating stripes across the embryo that mark the segments of the fly larva. If anything goes wrong, the stripes form in the wrong places or not at all.

"The experiment defines the first truly quantitative measure of how much information cells have available for crucial developmental decisions and how much of that information they actually use," said Wieschaus, who is a Howard Hughes Medical Institute investigator and earned the 1995 Nobel Prize in Physiology or Medicine for work on the genetic control of early embryonic development.

"This gives us an amazing tool for understanding how decision-making in biology actually works, one that is useful at levels ranging from the way proteins bind to DNA to how new biological pathways arise and compete during evolution," he said.

Mariela Petkova, a co-first author on the study, was an undergraduate working in Gregor's laboratory when she took on the question of how the cells use genetic and molecular information to find their locations and fates.

"We take seriously the idea that in a developing embryo cells need to "know" their position in order to make the correct developmental decisions," said Petkova, Class of 2012. "One can imagine cells as GPS devices which, instead of satellite signals, collect molecular ones to figure out their locations. We are able to decode how such molecular signals specify positions along the length of the early fly embryo."

Scientists have long known that the stripes form as a result of a cascade of steps that starts with the fly mother, who tucks into each egg an instruction set built from three different kinds of signaling molecules.

These signaling molecules spread through the embryo's body, forming concentration gradients that activate four so-called "gap" genes. The expression of these genes produces protein molecules that act on DNA segments known as enhancers to drive "pair-rule" genes to produce the striped pattern.

Petkova made detailed measurements of gap gene expression and the exact amounts of molecules produced in the cells along the long body axis. She started the research as part of her senior thesis and then deferred going to graduate school for a year to continue working on the project. She finished the work while on breaks from her studies at the Harvard University Biophysics Graduate Program.

With these measurements in hand, the theoretical physics part of the team was able to model how the cells use information to find their place in the embryo. The team included co-first author Gašper Tkačik, who earned his Ph.D. in physics at Princeton in 2007 and is now a faculty member at the Institute of Science and Technology Austria.

There are many ways that the cells could use the information encoded in the molecules. But the researchers chose to assume that the embryo makes use of all the available information encoded in the molecules. They called this the "optimal decoding approach."

With that assumption, Tkačik and Bialek used a relatively straightforward mathematical approach to predict where the stripes would form. The team then compared the predictions to the actual measurements of gap molecules and found they had accurately anticipated the locations of the stripes.

The real proof came when Petkova studied the eggs laid by flies which have mutations in the genes coding for the maternal signaling molecules that are at the start of the cascade. The team precisely predicted how various gene mutations altered the stripe pattern -- for example by making some of the stripes disappear or form in the wrong place.

"We used genetic manipulations to shuffle the gap gene patterns and 'trick' the cells into 'thinking' they were somewhere else along the length of the embryo," Petkova said. "We put these shuffled patterns through our decoder and built decoding maps, which told us where the cells were versus where they thought they were. Using these maps we predicted where the embryos would make stripes. When we looked at these mutant embryos under a microscope we actually found the stripes at the predicted locations! It was very satisfying."

The study gets at the question of whether it is possible to make robust predictions about biological systems starting from theoretical principles, according to the authors.

"This finding gives us theorists hope that our job in biology will not be forever relegated to fitting models from data, but actually predicting and quantitatively understanding why evolution came up with certain solutions," Tkačik said. "This gives promise, for at least a few example cases, that there may be a 'predictive theory for biology' -- an excellent motivation for future work."

Added Bialek: "A hallmark of modern physics is that general theoretical principles can be connected to an experiment in exquisite quantitative detail," he said. "It has long been difficult to imagine this sort of theory -- experiment interaction in the physics of biological systems -- living things seemed too complex, too messy. This work is one of the strongest examples of theory-experiment comparison that I have seen. I had always hoped that we would get to this level, but I didn't know when it would happen."

Wieschaus added: "Most scientists tend to think that biological processes are inherently sloppy and that cells achieve precision by multiple corrective steps and complicated interactive networks. Such processes certainly exist. What is amazing to me, however, is how precise and reproducible information can be at a single step in development, and once that information is there, how evolution and natural selection can push the cells to make maximum efficient use of that information."

The fruit fly (Drosophila melanogaster) is frequently used to learn general principles of biology that may apply to more sophisticated organisms such as humans. Whether organisms other than the fruit fly adhere to this optimal use of information remains to be seen, said Gregor.

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Mars rover Curiosity makes first gravity-measuring traverse on the Red Planet

In a selfie taken in mid-January 2019, Mars rover Curiosity prepares to enter a new, clay-mineral-rich unit on its traverse up Mount Sharp in Gale Crater. Mission scientists are anxious to see what a new gravity-measuring technique will reveal about the mountain and Gale Crater's history.
A clever use of non-science engineering data from NASA's Mars rover Curiosity has let a team of researchers, including an Arizona State University graduate student, measure the density of rock layers in 96-mile-wide Gale Crater.

The findings, to be published February 1, 2019, in the journal Science, show that the layers are more porous than scientists had suspected. The discovery also gives scientists a novel technique to use in the future as the rover continues its trek across the crater and up Mount Sharp, a three-mile-high mountain in its center.

"What we were able to do is measure the bulk density of the material in Gale Crater," says Travis Gabriel, a graduate student in ASU's School of Earth and Space Exploration. He worked on computing what the grain density should be for the rocks and ancient lakebed sediments the rover has been driving over.

"Working from the rocks' mineral abundances as determined by the Chemistry and Mineralogy instrument, we estimated a grain density of 2810 kilograms per cubic meter," he says. "However the bulk density that came out of our study is a lot less -- 1680 kilograms per cubic meter."

The much lower figure shows that the rocks have a reduced density most likely resulting from the rocks being more porous. This means the rocks have been compressed less than scientists have thought.

Like a Smartphone, but better

The engineering sensors used in the study were accelerometers and gyroscopes, much like those found in every smartphone. In a phone, these determine its orientation and motion. Curiosity's sensors do the same, but with much greater precision, helping engineers and mission controllers navigate the rover across the martian surface.

But while the rover is standing still, the accelerometers also measure the local force of gravity at that spot on Mars.

The team took the engineering data from the first five years of the mission -- Curiosity landed in 2012 -- and used it to measure the gravitational tug of Mars at more than 700 points along the rover's track. As Curiosity has been ascending Mount Sharp, the mountain began to tug on it, as well -- but not as much as scientists expected.

"The lower levels of Mount Sharp are surprisingly porous," says lead author Kevin Lewis of Johns Hopkins University. "We know the bottom layers of the mountain were buried over time. That compacts them, making them denser. But this finding suggests they weren't buried by as much material as we thought."

Making Mount Sharp

Planetary scientists have long debated the origin of Mount Sharp. Mars craters the size of Gale have central peaks raised by the shock of the impact that made the crater. This would account for part of the mound's height. But the upper layers of the mound appear to be made of wind-scoured sediments more easily eroded than rock.

Did these sediments once fill the entire bowl of Gale Crater? If so, they might have weighed heavily on the materials at the base, compacting them.

But the new findings suggest Mount Sharp's lower layers have been compacted by only a half-mile to a mile (1 to 2 kilometers) of material -- much less than if the crater had been completely filled.

"There are still many questions about how Mount Sharp developed, but this paper adds an important piece to the puzzle," said Ashwin Vasavada, Curiosity's project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, which manages the mission. "I'm thrilled that creative scientists and engineers are still finding innovative ways to make new scientific discoveries with the rover."

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Earth's largest extinction event likely took plants first

This is a view of Coalcliff in New South Wales, Australia, where researchers discovered evidence that Earth's largest extinction may have extinguished plant life nearly 400,000 years before marine animal species disappeared.
Little life could endure the Earth-spanning cataclysm known as the Great Dying, but plants may have suffered its wrath long before many animal counterparts, says new research led by the University of Nebraska-Lincoln.

About 252 million years ago, with the planet's continental crust mashed into the supercontinent called Pangaea, volcanoes in modern-day Siberia began erupting. Spewing carbon and methane into the atmosphere for roughly 2 million years, the eruption helped extinguish about 96 percent of oceanic life and 70 percent of land-based vertebrates -- the largest extinction event in Earth's history.

Yet the new study suggests that a byproduct of the eruption -- nickel -- may have driven some Australian plant life to extinction nearly 400,000 years before most marine species perished.

"That's big news," said lead author Christopher Fielding, professor of Earth and atmospheric sciences. "People have hinted at that, but nobody's previously pinned it down. Now we have a timeline."

The researchers reached the conclusion by studying fossilized pollen, the chemical composition and age of rock, and the layering of sediment on the southeastern cliffsides of Australia. There they discovered surprisingly high concentrations of nickel in the Sydney Basin's mud-rock -- surprising because there are no local sources of the element.

Tracy Frank, professor and chair of Earth and atmospheric sciences, said the finding points to the eruption of lava through nickel deposits in Siberia. That volcanism could have converted the nickel into an aerosol that drifted thousands of miles southward before descending on, and poisoning, much of the plant life there. Similar spikes in nickel have been recorded in other parts of the world, she said.

"So it was a combination of circumstances," Fielding said. "And that's a recurring theme through all five of the major mass extinctions in Earth's history."

If true, the phenomenon may have triggered a series of others: herbivores dying from the lack of plants, carnivores dying from a lack of herbivores, and toxic sediment eventually flushing into seas already reeling from rising carbon dioxide, acidification and temperatures.

'It Lets Us See What's Possible'

One of three married couples on the research team, Fielding and Frank also found evidence for another surprise. Much of the previous research into the Great Dying -- often conducted at sites now near the equator -- has unearthed abrupt coloration changes in sediment deposited during that span.

Shifts from grey to red sediment generally indicate that the volcanism's ejection of ash and greenhouse gases altered the world's climate in major ways, the researchers said. Yet that grey-red gradient is much more gradual at the Sydney Basin, Fielding said, suggesting that its distance from the eruption initially helped buffer it against the intense rises in temperature and aridity found elsewhere.

Though the time scale and magnitude of the Great Dying exceeded the planet's current ecological crises, Frank said the emerging similarities -- especially the spikes in greenhouse gases and continuous disappearance of species -- make it a lesson worth studying.

"Looking back at these events in Earth's history is useful because it lets us see what's possible," she said. "How has the Earth's system been perturbed in the past? What happened where? How fast were the changes? It gives us a foundation to work from -- a context for what's happening now."

Read more at Science Daily

Iguana-sized dinosaur cousin discovered in Antarctica

A slab containing fossils of Antarctanax.
Antarctica wasn't always a frozen wasteland -- 250 million years ago, it was covered in forests and rivers, and the temperature rarely dipped below freezing. It was also home to diverse wildlife, including early relatives of the dinosaurs. Scientists have just discovered the newest member of that family -- an iguana-sized reptile whose name means "Antarctic king."

"This new animal was an archosaur, an early relative of crocodiles and dinosaurs," says Brandon Peecook, a Field Museum researcher and lead author of a paper in the Journal of Vertebrate Paleontology describing the new species. "On its own, it just looks a little like a lizard, but evolutionarily, it's one of the first members of that big group. It tells us how dinosaurs and their closest relatives evolved and spread."

The fossil skeleton is incomplete, but paleontologists still have a good feel for the animal, named Antarctanax shackletoni (the former means "Antarctic king," the latter is a nod to polar explorer Ernest Shackleton). Based on its similarities to other fossil animals, Peecook and his coauthors (Roger Smith of the University of Witwatersrand and the Iziko South African Museum and Christian Sidor of the Burke Museum and University of Washington) surmise that Antarctanax was a carnivore that hunted bugs, early mammal relatives, and amphibians.

The most interesting thing about Antarctanax, though, is where it lived, and when. "The more we find out about prehistoric Antarctica, the weirder it is," says Peecook, who is also affiliated with the Burke Museum. "We thought that Antarctic animals would be similar to the ones that were living in southern Africa, since those landmasses were joined back then. But we're finding that Antarctica's wildlife is surprisingly unique."

About two million years before Antarctanax lived -- the blink of an eye in geologic time -- Earth underwent its biggest-ever mass extinction. Climate change, caused by volcanic eruptions, killed 90% of all animal life. The years immediately after that extinction event were an evolutionary free-for-all -- with the slate wiped clean by the mass extinction, new groups of animals vied to fill the gaps. The archosaurs, including dinosaurs, were one of the groups that experienced enormous growth. "Before the mass extinction, archosaurs were only found around the Equator, but after it, they were everywhere," says Peecook. "And Antarctica had a combination of these brand-new animals and stragglers of animals that were already extinct in most places -- what paleontologists call 'dead clades walking.' You've got tomorrow's animals and yesterday's animals, cohabiting in a cool place."

The fact that scientists have found Antarctanax helps bolster the idea that Antarctica was a place of rapid evolution and diversification after the mass extinction. "The more different kinds of animals we find, the more we learn about the pattern of archosaurs taking over after the mass extinction," notes Peecook.

Read more at Science Daily

Jan 30, 2019

Earth's continental nurseries discovered beneath mountains

The central Andes Mountains and surrounding landscape, as seen in this true-color image from NASA’s Terra spacecraft, formed over the past 170 million years as the Nazca Plate lying under the Pacific Ocean has forced its way under the South American Plate.
In his free time last summer, Rice University geoscientist Ming Tang made a habit of comparing the niobium content in various rocks in a global minerals database. What he found was worth skipping a few nights out with friends.

In a paper published this month by Nature Communications, Tang, Rice petrologist Cin-Ty Lee and colleagues offered an answer to one of Earth science's fundamental questions: Where do continents form?

"If our conclusions are correct, every piece of land that we are now sitting on got its start someplace like the Andes or Tibet, with very mountainous surfaces," said Tang, lead author of the study and a postdoctoral research associate in Rice's Department of Earth, Environmental and Planetary Sciences (EEPS). "Today, most places are flat because that is the stable stage of the continental crust. But what we found was that when the crust formed, it had to start out with mountain-building processes."

The connection between niobium, one of Earth's rarest elements, and continent formation is a story that plays out over billions of years at scales as small as molecules and as large as mountain ranges. The leading players are niobium and tantalum, rare metals so alike that geologists often think of them as twins.

"They have very similar chemical properties and behave almost identically in most geological processes," Tang said. "If you measure tantalum and niobium, you find that their ratio is nearly constant in Earth's mantle. That means that when you find more niobium in a rock, you will find more tantalum, and when you find less niobium, you will find less tantalum."

The mantle is Earth's thickest layer, spanning about 1,800 miles between the planet's core and its thin outer crust. Earth scientists believe that little, if anything, moves between the mantle and core, but the mantle and everything above it -- seafloor, oceans, continents and atmosphere -- are connected, and many of the atoms on Earth's surface today, including the atoms in humans and other living things, have cycled through the mantle one or more times in Earth's 4.6 billion years.

The rocks in continents are an exception. Geologists have found some that are up to 4 billion years old, which means they were formed near the surface and stayed on the surface, without being recycled into the mantle. That's due in part to the nature of continental crust, which is far less dense than the basaltic rocks beneath Earth's oceans. Lee, professor and EEPS department chair, said it's no coincidence that Earth is the only rocky planet known to have both continents and life.

"Every day we live on continents, and we take most of our resources from continents," Lee said. "We have oxygen in the air to breath and just the right temperature to support complex life. These things are so common that we take them for granted, but Earth didn't start off with these conditions. They developed later in Earth's history. And the emergence of continents is one of the things that shaped our planet and made it more livable."

Scientists still lack details about how continents got their start and how they grew to cover 30 percent of Earth's surface, but one big clue relates to niobium and tantalum, the geochemical twins.

"On average, the rocks in continental crust have about 20 percent less niobium than they should compared to the rock we see everywhere else," Tang said. "We believe this missing niobium is tied to the mystery of continents. By solving or finding the missing the niobium, we can get important information about how continents form."

Geologists have known about the imbalance for decades. And it certainly suggests that the geochemical processes that produce continental crust also remove niobium. But where was the missing niobium?

That nagging question prompted Tang to spend his free time perusing records in the Max Planck Institute's GEOROC database, a comprehensive global collection of published analyses of volcanic rocks.

Based on those searches and months of follow-up tests, Tang, Lee and colleagues offer the first physical evidence that "arclogites" (pronounced ARC-loh-jyts) are responsible for the missing niobium. Arclogites are cumulates, the leftover dross that accumulates near the base of continental arcs. On rare occasions, chunks of these cumulates erupt onto the surface from volcanos.

The Rice group first sent arclogite samples that Lee had collected in Arizona to their collaborator, Kang Chen, a research fellow based at the China University of Geosciences in Wuhan. Chen spent a month getting precise readings of the relative amounts of niobium and tantalum in the samples. The rocks were created when the High Sierras were an active continental arc, like the Andes today.

Chen's tests confirmed high niobium-tantalum ratios, but to better understand the mechanism by which this signature was developed, Tang and Lee used high precision laser ablation and "inductively coupled plasma mass spectrometry" in Lee's laboratory at Rice to reveal the mineral rutile was responsible.

"Rutile is the mineral that hosts the niobium," he said. "It's a naturally occurring form of titanium oxide, and it is what actually 'sees' the difference between niobium and tantalum and captures one more than the other."

But that happens only under specific conditions. For example, Tang said that at temperatures above 1,000 degrees Celsius, rutile traps normal ratios of tantalum and niobium. It only begins to prefer niobium when temperatures drop below 1,000 degrees Celsius. Tang said the only known place with that set of conditions is deep beneath continental arcs, like the Andes today or the High Sierras about 80 million years ago.

"The reason you need high pressure is that titanium oxide is relatively rare," he said. "You need very high pressure to force it to crystalize and fall out of the magma."

In an earlier arclogite study published in Science Advances last May, Tang and Lee discovered a subtle chemical signature that can explain why continental crust is iron-depleted. Lee said that finding and the discovery about rutile and niobium illustrate the central importance of continental arcs in Earth history.

Read more at Science Daily

Vitamin D could lower the risk of developing diabetes

The benefits of vitamin D in promoting bone health are already well known. A new study out of Brazil suggests that vitamin D also may promote greater insulin sensitivity, thus lowering glucose levels and the risk of developing type 2 diabetes. Results are published online today in Menopause, the journal of The North American Menopause Society (NAMS).

Other recent studies have shown a clear relationship between vitamin D and glycemic control, suggesting that vitamin D increases insulin sensitivity and improves pancreatic beta-cell function. In this cross-sectional study involving 680 Brazilian women aged 35 to 74 years, the goal was to evaluate the possible association between vitamin D deficiency and increased glycemia.

Of the women interviewed, 24 (3.5%) reported using vitamin D supplements. Vitamin D supplementation was found to be negatively associated with high glucose levels. Habitual exposure to the sun also provided the same association, demonstrating that vitamin D deficiencies are associated with high blood glucose levels.

Study results appear in the article "Higher serum levels of vitamin D are associated with lower blood glucose levels."

"Although a causal relationship has not been proven, low levels of vitamin D may play a significant role in type 2 diabetes mellitus," says Dr. JoAnn Pinkerton, NAMS executive director. "Vitamin D supplementation may help improve blood sugar control, but intervention studies are still needed."

From Science Daily

Long-necked dinosaurs rotated their forefeet to the side

These are well preserved footprints of the find site in Morocco, with clearly visible claw impressions.
Long-necked dinosaurs (sauropods) could orient their forefeet both forward and sideways. The orientation of their feet depended on the speed and centre of mass of the animals. An international team of researchers investigated numerous dinosaur footprints in Morocco at the foot of the Atlas Mountains using state-of-the-art methods. By comparing them with other sauropods tracks, the scientists determined how the long-necked animals moved forward. The results have now been published in the Journal of Vertebrate Paleontology.

"Long-necked dinosaurs" (sauropods) were among the most successful herbivores of the Mesozoic Era -- the age of the dinosaurs. Characteristic for this group were a barrel-shaped body on columnar legs as well as an extremely long neck, which ended in a relatively small head. Long-necked dinosaurs existed from about 210 to 66 million years ago -- they thus had been able to assert themselves on earth for a very long period. Also their gigantism, with which they far surpassed other dinosaurs, points at their success.

Sauropods included the largest land animals in Earth history, some over 30 metres long and up to 70 tonnes in weight. "However, it is still unclear how exactly these giants moved," says Jens Lallensack, paleontologist at the Institute of Geosciences and Meteorology at the University of Bonn in Germany. The limb joints were partly cartilaginous and therefore not fossilised, allowing only limited conclusions about the range of movement.

Detective work with 3D computer analyses

The missing pieces of the puzzle, however, can be reconstructed with the help of fossil footprints of the giants. An international team of researchers from Japan, Morocco and Germany, led by the University of Bonn, has now investigated an unique track site in Morocco at the foot of the Atlas Mountains. The site consists of a surface of 54 x 6 metres which was vertically positioned during mountain formation and shows hundreds of individual footprints, some of which overlap. A part of these footprints could be assigned to a total of nine trackways (sequences of individual footprints). "Working out individual tracks from this jumbled mess of footprints was detective work and only possible through the analysis of high-resolution 3D models on the computer," says Dr. Oliver Wings of the Zentralmagazin Naturwissenschaftlicher Sammlungen der Martin-Luther-Universität Halle-Wittenberg in Germany.

The researchers were amazed by the results: the trackways are extremely narrow -- the right and left footprints are almost in line. Also, the forefoot impressions are not directed forwards, as is typical for sauropod tracks, but point to the side, and sometimes even obliquely backwards. Even more: The animals were able to switch between both orientations as needed. "People are able to turn their palms downwards by crossing the ulna and radius," says Dr. Michael Buchwitz of the Museum für Naturkunde Magdeburg. However, this complicated movement is limited to mammals and chameleons in today's terrestrial vertebrates. It was not possible in other animals, including dinosaurs. Sauropods must therefore have found another way of turning the forefoot forwards.

How can the rotation of the forefoot be explained?

How can the rotation of the forefoot in the sauropod tracks be explained? The key probably lies in the mighty cartilage layers, which allowed great flexibility in the joints, especially in the shoulder. But why were the hands rotated outwards at all? "Outwardly facing hands with opposing palms were the original condition in the bipedal ancestors of the sauropods," explains Shinobu Ishigaki of the Okayama University of Science, Japan. The question should therefore be why most sauropods turned their forefeet forwards -- an anatomically difficult movement to implement.

Read more at Science Daily

Dangerous bee virus might be innocent bystander

Professor Madeleine Beekman with beehives.
Researchers at the University of Sydney have found that the relationship between the tissue-sucking Varroa mite and virulence of a virus of honey bees, has most likely been misunderstood.

The study challenges the long-held belief that the parasitic Varroa mite -- a mite that sucks the tissue of honey bees -- transmits the Deformed Wing Virus of honeybees and in doing so changes the virus to make it more virulent and deadly.

Research published today in Proceedings of The Royal Society B: Biological Sciences concludes that this belief is incorrect.

"The prevailing wisdom is that the mite selects for very virulent strains of the virus," said Professor Madeleine Beekman from the School of Life and Environmental Sciences at the University of Sydney.

"For that reason, the virus is now known as a very dangerous virus and the Australian beekeepers are adamant this virus should not get into the country. In fact, there is legislation that prevents the import of any bee products that could contain the virus. But our work shows that the virus is more likely to be an innocent bystander."

Australia is the only country in the world to remain free of the Varroa mite. This makes Australian honey and wax valuable because it is free of chemical residues used to eliminate the parasite.

"Australia is the last country on the planet to produce completely pure honey," says Professor Beekman. "But the mite is highly likely to arrive in Australia on shipping containers so we need to understand how the mite and the virus interact."

Professor Beekman and her team in the Behaviour and Genetics of Social Insects Lab injected honey bee pupae with high levels of Deformed Wing Virus which is carried by the mite to test if the virus was highly virulent due to changes in the transmission route that occurred via the Varroa mite.

In the absence of the mite, the virus needs to be transmitted to other bees via direct interactions between an infected and non-infected bee. Varroa does the transmission by biting one bee and then another.

The team found the transmission route used by the Varroa mite selects against viruses that are much more virulent than the Deformed Wing Virus, such as Sacbrood virus and Black queen cell virus. These viruses normally suppress Deformed Wing Virus. The elimination of Sacbrood and Black Queencell virus leaves just Deformed Wing Virus, which does not kill the bees.

"Our work therefore changes our understanding of the effect Varroa has on Deformed Wing Virus and the health of honey bee colonies," Professor Beekman said.

"It means we don't have to be scared of the virus. Instead we need to focus on eliminating the mite and reducing its numbers."

The results will also have an impact on the ways the Australian beekeepers can prepare themselves for the arrival of Varroa.

"Many countries actively select for honey bee populations that can tolerate the Varroa mite without treatment. Australian beekeepers would like to import the sperm from such populations to start preparing their honey bees for when the mite arrives," said Professor Beekman.

"But the importation of the sperm is currently forbidden because of the threat of Deformed Wing Virus, which can be present in bee sperm. Perhaps beekeepers can now convince the authorities that bee sperm is safe."

Read more at Science Daily

Layered cocktails inspire new form of male birth control

This colorful layered cocktail, called a Galaxy, provided the inspiration for a new form of male contraceptive tested in rats.
For decades, women have shouldered most of the burden of contraception. However, long-term use of female birth control pills could increase the risk for side effects such as blood clots or breast cancer. Now, inspired by colorful layered cocktails, researchers have developed a medium-term, reversible male contraceptive. They report their results in the journal ACS Nano.

Common forms of male contraception are either short-term (condoms) or long-term (vasectomy). However, condoms can fail, and vasectomies, while effective, are not often reversible. Xiaolei Wang and colleagues wanted to devise a medium-term, reversible form of male contraception. They drew inspiration from cocktails, such as the Galaxy, that bartenders make by layering colorful liquids in a glass. If the beverage is stirred or heated, the layers combine into a uniform liquid. Wang and colleagues wondered if they could use a similar approach to inject layers of materials to block the vas deferens, the duct that conveys sperm from the testicle to the urethra. Applying heat would cause the layers to mix, breaking them down and "unplugging the pipeline."

The team tested their approach in male rats. They sequentially injected four layers of materials into the vas deferens: a hydrogel that forms a physical barrier to sperm; gold nanoparticles, which heat up when irradiated with near-infrared light; ethylenediaminetetraacetic acid (EDTA), a chemical that breaks down the hydrogel and also kills sperm; and finally, another layer of gold nanoparticles. The injected materials kept the rats from impregnating females for more than 2 months. However, when the researchers shone a near-infrared lamp on the rats for a few minutes, the layers mixed and dissolved, allowing the animals to produce offspring. The researchers say that while this pilot experiment is promising, more research is needed to verify the safety of the materials.

From Science Daily

Jan 29, 2019

'Superbug gene' found in one of the most remote places on Earth

Antibiotic-Resistant Genes (ARGs) that were first detected in urban India have been found 8,000 miles away in one of the last 'pristine' places on earth, a new study has shown.

Soil samples taken in the Kongsfjorden region of Svalbard have now confirmed the spread of blaNDM-1 into the High Arctic -- an ARG originally found in Indian clinical settings, which conditionally provides multidrug resistance (MDR) in microorganisms.

Worldwide spread of blaNDM-1 and other MDR genes is a growing concern because they often target "last resort" classes of antibiotics, including Carbapenems.

Carried in the gut of animals and people, the research team, led by Newcastle University's Professor David Graham, say that blaNDM-1 and other medically-important ARGs were found in Arctic soils that were likely spread in the faecal matter of birds, other wildlife and human visitors to the area.

"Polar regions are among the last presumed pristine ecosystems on Earth, providing a platform for characterizing pre-antibiotic era background resistance against which we could understand rates of progression of AR 'pollution'," says Professor Graham, an environmental engineer at Newcastle University who has spent 15 years studying the environmental transmission of antibiotic resistance around the world.

"But less than three years after the first detection of the blaNDM-1 gene in the surface waters of urban India we are finding them thousands of miles away in an area where there has been minimal human impact.

"Encroachment into areas like the Arctic reinforces how rapid and far-reaching the spread of antibiotic resistance has become, confirming solutions to AR must be viewed in global rather than just local terms."

Concern over the spread of Antibiotic-Resistant (AR) genes

Increasing antibiotic resistance is a global health crisis. An example is NDM-1, which is a protein that can confer resistance in a range of bacteria. NDM-1 was first identified in New Delhi and coded by the resistant gene blaNDM-1.

Strains that carry blaNDM-1 were first found in clinical settings in 2008, but by 2010 blaNDM-1 was found in surface waters in Delhi. Since then, the resistant gene has been found in over 100 countries, including new variants.

There are currently few antibiotics to combat bacteria that are resistant to Carbapenems -- still a last-resort antibiotic class -- and worldwide spread of blaNDM-1 and related ARGs is a concern.

"What humans have done through excess use of antibiotics on global scales is accelerate the rate of evolution, creating a new world of resistant strains that never existed before," explains Graham.

"Through the overuse of antibiotics, faecal releases and contamination of drinking water, we have consequentially speeded-up the rate at which superbugs might evolve.

"For example, when a new drug is developed, natural bacteria can rapidly adapt and can become resistant; therefore very few new drugs are in the pipeline because it simply isn't cost-effective to make them."

Benchmark for tracking resistance

Published today in the academic journal Environmental International, this latest research was carried out by an international team of experts from the Universities of Newcastle, York and Kansas and the Chinese Academy of Science in Xiamen, and was funded by the UK Natural Environmental Research Council and other agencies.

Analysing the extracted DNA from forty soil cores at eight locations along Kongsfjorden, a total of 131 ARGs were detected.

"The resistance genes detected were associated with nine major antibiotic classes, including aminoglycosides, macrolides and ?-lactams, which are used to treat many infections. As an example, a gene that confers MDR in Tuberculosis was found in all cores, whereas blaNDM-1 was detected in more than 60% of the soil cores in the study.

"This finding has huge implications for global AR spread," warns Graham. "A clinically important ARG originating from South Asia is clearly not 'local' to the Arctic."

"Identifying an ARG 'gradient' across the study landscape, which varies as a function of human and wildlife impact, shows there are still isolated Polar locations where ARG levels are so low they might provide nature's baseline of antimicrobial resistance," Graham says.

"The gradient of resistance genes closely reflects corresponding indicators of wastes in the geochemistry, which suggests a novel basis for identifying sites for further AMR research" adds lead author, Dr Clare McCann, of Newcastle University.

"The only way we are going to win this fight is to understand all pathways that lead to antibiotic resistance.

Read more at Science Daily

The hidden treasure of digital piracy? Can boost bottom line for manufacturers, retailers

HBO's popular television series "Game of Thrones" returns in April, but millions of fans continue to illegally download the program, giving it the dubious distinction of being the most pirated program.

Many may wonder why the TV network hasn't taken a more aggressive approach to combating illegal streaming services and downloaders. Perhaps it is because the benefits to the company outweigh the consequences. Research analysis by faculty in Indiana University's Kelley School of Business and two other schools found that a moderate level of piracy can have a positive impact on the bottom line for both the manufacturer and the retailer -- and not at the expense of consumers.

"When information goods are sold to consumers via a retailer, in certain situations, a moderate level of piracy seems to have a surprisingly positive impact on the profits of the manufacturer and the retailer while, at the same time, enhancing consumer welfare," wrote Antino Kim, assistant professor of operations and decision technologies at Kelley, and his co-authors.

"Such a win-win-win situation is not only good for the supply chain but is also beneficial for the overall economy."

While not condoning piracy, Kim and his colleagues were surprised to find that it can actually reduce, or completely eliminate at times, the adverse effect of double marginalization, an economic concept where both manufacturers and retailers in the same supply chain add to the price of a product, passing these markups along to consumers.

The professors found that, because piracy can affect the pricing power of both the manufacturer and the retailer, it injects "shadow" competition into an otherwise monopolistic market.

"From the manufacturer's point of view, the retailer getting squeezed is a good thing," Kim said. "It can't mark up the product as before, and the issue of double marginalization diminishes. Vice versa, if the manufacturer gets squeezed, the retailer is better off.

"What we found is, by both of them being squeezed together -- both at the upstream and the downstream levels -- they are able to get closer to the optimal retail price that a single, vertically integrated entity would charge."

In the example of "Game of Thrones," HBO is the upstream "manufacturer" in the supply chain, and cable and satellite TV operators are the downstream "retailers."

Kim and his co-authors -- Atanu Lahiri, associate professor of information systems at the University of Texas-Dallas, and Debabrata Dey, professor of information systems at the University of Washington -- presented their findings in the article, "The 'Invisible Hand' of Piracy: An Economic Analysis of the Information-Goods Supply Chain," published in the latest issue of MIS Quarterly.

They suggest that businesses, government and consumers rethink the value of anti-piracy enforcement, which can be quite costly, and consider taking a moderate approach. Australia, for instance, due to prohibitive costs, scrapped its three-strikes scheme to track down illegal downloaders and send them warning notices. Though the Australian Parliament passed a new anti-piracy law last year, its effectiveness remains unclear until after it is reviewed in two years.

As with other studies, Kim and his colleagues found that when enforcement is low and piracy is rampant, both manufacturers and retailers suffer. But they caution against becoming overzealous in prosecuting illegal downloaders or in lobbying for more enforcement.

"Our results do not imply that the legal channel should, all of a sudden, start actively encouraging piracy," they said. "The implication is simply that, situated in a real-world context, our manufacturer and retailer should recognize that a certain level of piracy or its threat might actually be beneficial and should, therefore, exercise some moderation in their anti-piracy efforts.

Read more at Science Daily

Engineering a cancer-fighting virus

This is a comparison of cancer cells and normal cells after being infected with the dl355 adenovirus. The top four cell types listed on the left (HeLa, C33A, A549, and H1299) are cancer cells, and the bottom two (BJ and WI38) are normal cells. As the amount of dl355 virus administered to the cancer cells increased (represented by MOI), more cancer cells died in 7 days, while the normal cells continued to live.
An engineered virus kills cancer cells more effectively than another virus currently used in treatments, according to Hokkaido University researchers.

Hokkaido University researchers have engineered a virus that selectively targets and kills cancer cells. The virus, called dl355, has an even stronger anticancer effect than another engineered virus currently used in clinical practice, according to a study published in the journal Oncology Reports.

Molecular oncologist Fumihiro Higashino and colleagues deleted a gene involved in viral replication, called E4orf6, from a type of adenovirus. The team previously discovered that E4orf6 stabilizes a type of mRNA called ARE-mRNAs in the infected cells enabling viral replication. ARE-mRNAs are known to be stable in stressed cells and cancer cells, but rapidly degrade in normal cells.

In laboratory tests, they found that their modified adenovirus, called dl355, replicated and increased its number significantly more in cancer cells than it did in normal cells. Higashino explains "The E4orf6-lacking virus relies on the stable ARE-mRNAs in cancer cells for its replication."

Some viruses can be used to treat cancers, as they replicate within the cells until they burst and die. The researchers infected several types of cultured cancer cells with 100 dl355 virus particles per cell and found that nearly all the cancer cells died within seven days. In contrast, most normal cells infected with the virus did not die, even after seven days. Several cancer cell lines managed to survive low doses of dl355, but all cancer cells were killed by the virus as the dose was increased. Tumour growth was also significantly suppressed when dl355 was administered to human tumour cells grown in mice.

Finally, the team compared the anticancer effects of dl355 with another anticancer adenovirus currently used in clinical practice, called dl1520. dl355 replication was higher in all cancer cell lines tested, including cervical and lung cancer cells, and was better at killing all but one type of cancer cell, compared to dl1520. Both viruses only killed very few normal cells.

The findings suggest that dl355 has potential to be an effective anticancer treatment, the team concludes. They suggest enhancing the stabilization of ARE-mRNAs in cancer cells could even further strengthen its effect, but Professor Higashino notes that further research is required. "While we think dl355 has the potential to be an effective treatment method in dealing with many types of cancers, much more research needs to be done. When we think of a timeline, at least five more years of further research may be required, possible more, on top of clinical trials," Professor Higashino noted.

From Science Daily

Missing-link in planet evolution found

This is an artist's impression of the newly discovered object.
For the first time ever, astronomers have detected a 1.3 km radius body at the edge of the Solar System. Kilometer sized bodies like the one discovered have been predicted to exist for more than 70 years. These objects acted as an important step in the planet formation process between small initial amalgamations of dust and ice and the planets we see today.

The Edgeworth-Kuiper Belt is a collection of small celestial bodies located beyond Neptune's orbit. The most famous Edgeworth-Kuiper Belt Object is Pluto. Edgeworth-Kuiper Belt Objects are believed to be remnants left over from the formation of the Solar System. While small bodies like asteroids in the inner Solar System have been altered by solar radiation, collisions, and the gravity of the planets over time; objects in the cold, dark, lonely Edgeworth-Kuiper Belt preserve the pristine conditions of the early Solar System. Thus astronomers study them to learn about the beginning of the planet formation process.

Edgeworth-Kuiper Belt Objects with radii from 1 kilometer to several kilometers have been predicted to exist, but they are too distant, small, and dim for even world-leading telescopes, like the Subaru Telescope, to observe directly. So a research team led by Ko Arimatsu at the National Astronomical Observatory of Japan used a technique known as occultation: monitoring a large number of stars and watching for the shadow of an object passing in front of one of the stars. The OASES (Organized Autotelescopes for Serendipitous Event Survey) team placed two small (28 cm) telescopes on the roof of the Miyako open-air school on Miyako Island, Miyakojima-shi, Okinawa Prefecture, Japan, and monitored approximately 2000 stars for a total of 60 hours.

Analyzing the data, the team found an event consistent with a star appearing to dim as it is occulted by a 1.3 km radius Edgeworth-Kuiper Belt Object. This detection indicates that kilometer sized Edgeworth-Kuiper Belt Objects are more numerous than previously thought. This supports models where planetesimals first grow slowly into kilometer sized objects before runaway growth causes them to merge into planets.

Arimatsu explains, "This is a real victory for little projects. Our team had less than 0.3% of the budget of large international projects. We didn't even have enough money to build a second dome to protect our second telescope! Yet we still managed to make a discovery that is impossible for the big projects. Now that we know our system works, we will investigate the Edgeworth-Kuiper Belt in more detail. We also have our sights set on the still undiscovered Oort Cloud out beyond that."

Read more at Science Daily

Fluid-inspired material self-heals before your eyes

The fluid-inspired material self-heals in seconds when scratched, scraped or cracked.
It's hard to believe that a tiny crack could take down a gigantic metal structure. But sometimes bridges collapse, pipelines rupture and fuselages detach from airplanes due to hard-to-detect corrosion in tiny cracks, scratches and dents.

A Northwestern University team has developed a new coating strategy for metal that self-heals within seconds when scratched, scraped or cracked. The novel material could prevent these tiny defects from turning into localized corrosion, which can cause major structures to fail.

"Localized corrosion is extremely dangerous," said Jiaxing Huang, who led the research. "It is hard to prevent, hard to predict and hard to detect, but it can lead to catastrophic failure."

When damaged by scratches and cracks, Huang's patent-pending system readily flows and reconnects to rapidly heal right before the eyes. The researchers demonstrated that the material can heal repeatedly -- even after scratching the exact same spot nearly 200 times in a row.

The study was published today (Jan. 28) in Research, the first Science Partner Journal recently launched by the American Association for the Advancement of Science (AAAS) in collaboration with the China Association for Science and Technology (CAST). Huang is a professor of materials science and engineering in Northwestern's McCormick School of Engineering.

While a few self-healing coatings already exist, those systems typically work for nanometer- to micron-sized damages. To develop a coating that can heal larger scratches in the millimeter-scale, Huang and his team looked to fluid.

"When a boat cuts through water, the water goes right back together," Huang said. "The 'cut' quickly heals because water flows readily. We were inspired to realize that fluids, such as oils, are the ultimate self-healing system."

But common oils flows too readily, Huang noted. So he and his team needed to develop a system with contradicting properties: fluidic enough to flow automatically but not so fluidic that it drips off the metal's surface.

The team met the challenge by creating a network of lightweight particles -- in this case graphene capsules -- to thicken the oil. The network fixes the oil coating, keeping it from dripping. But when the network is damaged by a crack or scratch, it releases the oil to flow readily and reconnect. Huang said the material can be made with any hollow, lightweight particle -- not just graphene.

"The particles essentially immobilize the oil film," Huang said. "So it stays in place."

Read more at Science Daily

Jan 28, 2019

To catch a wave, rocket launches from top of world

Earth's magnetosphere, showing the northern and southern polar cusps (illustration).
On Jan. 4, 2019, at 4:37 a.m. EST the CAPER-2 mission launched from the Andøya Space Center in Andenes, Norway, on a 4-stage Black Brant XII sounding rocket. Reaching an apogee of 480 miles high before splashing down in the Arctic Sea, the rocket flew through active aurora borealis, or northern lights, to study the waves that accelerate electrons into our atmosphere.

CAPER-2, short for Cusp Alfvén and Plasma Electrodynamics Rocket-2, is a sounding rocket mission -- a type of spacecraft that carries scientific instruments on short, targeted trips to space before falling back to Earth. In addition to their relatively low price tags and quick development time, sounding rockets are ideally suited for launching into transient events -- like the sudden formation of the aurora borealis, or northern lights.

For CAPER-2 scientists, flying through an aurora provides a peek into a process as fundamental as it is complex: How do particles get accelerated throughout space? NASA studies this phenomenon in an effort to better understand not only the space environment surrounding Earth -- and thus protect our technology in space from radiation -- but also to help understand the very nature of stars and atmospheres throughout the solar system and beyond.

"Throughout the universe you have charged particles getting accelerated -- in the Sun's atmosphere, in the solar wind, in the atmospheres of other planets, and in astrophysical objects," said Jim LaBelle, space physicist at Dartmouth College in Hanover, New Hampshire, and principal investigator for the CAPER-2 mission. "An aurora presents us with a local laboratory where we can observe these acceleration processes close at hand."

Technically, the CAPER-2 team is interested in what happens just before an aurora starts glowing. Electrons, pouring into our atmosphere from space, collide with atmospheric gases and trigger the aurora's glow. Somehow, they pick up speed along the way.

"By the time they crash into our atmosphere, these electrons are traveling over 10 times faster than they were before," said Doug Rowland, space physicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who also studies particle acceleration. "We still don't understand the fundamental physics of how that happens."

The CAPER-2 team focused on a special kind of aurora that forms during the day. Unlike the nighttime aurora, the daytime aurora is triggered by electrons that stream in directly from the Sun -- and we know far less about them.

"There's been a huge amount of research done on the regular nighttime aurora, but the daytime aurora is much less studied," said Craig Kletzing, space physicist at the University of Iowa in Iowa City and coinvestigator for the mission. "There are good indications that there are some similarities and there are also some differences."

The team is focusing on how the electrons that create daytime auroras are jostled around by waves, in ways that may or may not differ from nighttime auroras. Two kinds of waves are of special interest, and have opposite effects. Alfvén waves, named after Swedish Nobel laureate Hannes Alfvén who first predicted their existence in 1942, are thought to accelerate the electrons. These huge waves -- measuring tens to hundreds of miles long from peak to peak -- propagate along Earth's magnetic field lines, whipping electrons to and fro.

On the other side are Langmuir waves, which are generated by the electrons themselves -- a process that steals some of the electrons' energy and slows them down. CAPER-2 will carry a high-resolution wave-particle correlator to measure them, the first sounding rocket mission to do so for the daytime aurora.

"This is very data-intensive," said LaBelle. "It's unique to sounding rockets to be able to look at this mechanism in this level of detail."

For the launch, the CAPER-2 team traveled to northern Norway, one of the few places that can put a rocket within range of the daytime aurora. Every day, northern Norway rotates under an opening in Earth's magnetic field known as the northern polar cusp, where particles from the Sun can funnel into our upper atmosphere.

Meeting the aurora right where they form is the best way to understand physical processes that are far too large to replicate in a lab.

Read more at Science Daily

Humans colonized diverse environments in Southeast Asia and Oceania during the Pleistocene

Cagayan, Northern Luzon, the Philippines -- Southeast Asia offers a particularly exciting region in regard of early hominin movements across the supposed "Movius Line" a boundary previously argued to separate populations. Records from the region can be linked to a variety of hominins throughout the Pleistocene, including Homo erectus, Homo floresiensis (or "the Hobbit"), and Homo sapiens.
Investigations into what it means to be human have often focused on attempts to uncover the earliest material traces of 'art', 'language', or technological 'complexity'. More recently, however, scholars have begun to argue that more attention should be paid to the ecological uniqueness of our species. A new study, published in Archaeological Research in Asia, reviews the palaeoecological information associated with hominin dispersals into Southeast Asia and Oceania throughout the Pleistocene (1.25 Ma to 12 ka). Our species' ability to specialize in the exploitation of diverse and 'extreme' settings in this part of the world stands in stark contrast to the ecological adaptations of other hominin taxa, and reaffirms the utility of exploring the environmental adaptations of Homo sapiens as an avenue for understanding what it means to be human.

The paper, published by scientists from the Max Planck Institute for the Science of Human History focuses on hominin movements across the supposed 'Movius Line' a boundary previously argued to separate populations with different cultural and cognitive capacities. While such divisions and assumptions are now clearly outdated, the authors argue that focus on this part of the world may, instead, be used to study the different patterns of colonization of diverse tropical and maritime habitats by different members of our ancestral line. As Noel Amano, co-author on the study states, 'analysis of biogeochemical records, animal assemblages, and fossil plant records associated with hominin arrival can be used to reconstruct the degree to which novel or specialized adaptations were required at a given place and time'.

Southeast Asia offers a particularly exciting region in this regard as such records can be linked to a variety of hominins throughout the Pleistocene, including Homo erectus, Homo floresiensis (or 'the Hobbit'), and Homo sapiens. As Patrick Roberts, lead author of the study states the accumulated evidence shows, 'While earlier members of our genus appear to have followed riverine and lacustrine corridors, Homo sapiens specialized in adaptations to tropical rainforests, faunally depauperate island settings, montane environments, and deep-water marine habitats.' The authors hope that, in future, the growth of new methods and records for determining past hominin ecologies will enable similar comparisons to be undertaken in different parts of the world, further testing the unique capacities of our species during its global expansion.

From Science Daily