Education linked to higher risk of short-sightedness

A new study provides "strong evidence" that more time spent in education is a risk factor for myopia.

Spending more years in full time education is associated with a greater risk of developing short-sightedness (myopia), finds a study published by The BMJ today.

The researchers say their study provides "strong evidence" that more time spent in education is a risk factor for myopia, and that the findings "have important implications for educational practices."

Myopia, or short-sightedness, is a leading cause of visual impairment worldwide. Currently, 30-50% of adults in the United States and Europe are myopic, with levels of 80-90% reported in school leavers in some East Asian countries.

Based on existing trends, the number of people affected by myopia worldwide is expected to increase from 1.4 billion to 5 billion by 2050, affecting about half of the world's population. Almost 10% of these people (around 9 million) will have high myopia, which carries a greater risk of blindness.

Many studies have reported strong links between education and myopia, but it is not clear whether increasing exposure to education causes myopia, myopic children are more studious, or socioeconomic position leads to myopia and higher levels of education.

So researchers based at the University of Bristol and Cardiff University set out to determine whether education is a direct (causal) risk factor for myopia, or myopia is a causal risk factor for more years in education.

Using a technique called Mendelian randomisation, they analysed 44 genetic variants associated with myopia and 69 genetic variants associated with years of schooling for 67,798 men and women aged 40 to 69 years from the UK Biobank database.

Analysing genetic information in this way avoids some of the problems that afflict traditional observational studies, making the results less prone to unmeasured (confounding) factors, and therefore more likely to be reliable.

An association that is observed using Mendelian randomisation therefore strengthens the inference of a causal relationship.

After taking account of potentially influential factors, Mendelian randomisation analyses suggested that every additional year of education was associated with more myopia (a refractive error of ?0.27 dioptres a year).

To put this into context, a university graduate from the UK with 17 years of education would, on average, be at least ?1 dioptre more myopic than someone who left school at 16 (with 12 years of education). This level of myopia would mean needing glasses for driving.

By contrast, there was little evidence to suggest that myopia led people to remain in education for longer.

The researchers point to some study limitations. For example, UK Biobank participants have been shown to be more highly educated, have healthier lifestyles, and report fewer health issues compared with the general UK population, which may have affected the results. However, there was little evidence that this could explain their findings.

"This study shows that exposure to more years in education contributes to the rising prevalence of myopia, and highlights a need for further research and discussion about how educational practices might be improved to achieve better outcomes without adversely affecting vision," they conclude.

In a linked editorial, Professor Ian Morgan at the Australian National University and colleagues say the evidence suggests that it is not only genes but environmental and social factors that may have major effects on myopia.

They point to East Asia, where early intense educational pressures combined with little time for play outdoors has led to almost 50% of children being myopic by the end of primary school, compared with less than 10% in a study of British children.

"Early onset allows more time for myopia to progress to high and potentially pathological myopia," they warn, and they argue that education systems "must change to help protect the visual health of future generations."

In a linked opinion piece, study author Denize Atan also points to evidence showing that time spent outdoors in childhood partially protects against the development of myopia.

Read more at Science Daily

Remarkable skill of ancient Peru's cranial surgeons

More ancient skulls bearing evidence of trepanation -- a telltale hole surgically cut into the cranium -- have been found in Peru than the combined number found in the rest of the world.

Even with a highly skilled neurosurgeon, the most effective anesthesia, and all the other advances of modern medicine, most of us would cringe at the thought of undergoing cranial surgery today.

After all, who needs a hole in the head? Yet for thousands of years, trepanation -- the act of scraping, cutting, or drilling an opening into the cranium -- was practiced around the world, primarily to treat head trauma, but possibly to quell headaches, seizures and mental illnesses, or even to expel perceived demons.

But, according to a new study led by the University of Miami Miller School of Medicine's David S. Kushner, M.D., clinical professor of physical medicine and rehabilitation, trepanation was so expertly practiced in ancient Peru that the survival rate for the procedure during the Incan Empire was about twice that of the American Civil War -- when, more three centuries later, soldiers were trepanned presumably by better trained, educated and equipped surgeons.

"There are still many unknowns about the procedure and the individuals on whom trepanation was performed, but the outcomes during the Civil War were dismal compared to Incan times," said Kushner, a neurologist who has helped scores of patients recover from modern-day traumatic brain injuries and cranial surgeries. "In Incan times, the mortality rate was between 17 and 25 percent, and during the Civil War, it was between 46 and 56 percent. That's a big difference. The question is how did the ancient Peruvian surgeons have outcomes that far surpassed those of surgeons during the American Civil War?"

In their study published in the June issue of World Neurosurgery, "Trepanation Procedures/Outcomes: Comparison of Prehistoric Peru with Other Ancient, Medieval, and American Civil War Cranial Surgery," Kushner and his co-authors -- biological anthropologists John W. Verano, a world authority on Peruvian trepanation at Tulane University, and his former graduate student, Anne R. Titelbaum, now of the University of Arizona College of Medicine -- can only speculate on the answer.

But hygiene, or more accurately the lack of it during the Civil War, may have contributed to the higher mortality rates in the later time period. According to the study, which relied on Verano's extensive field research on trepanation over a nearly 2,000-year period in Peru and a review of the scientific literature about trepanation around the world, Civil War surgeons often used unsterilized medical tools and their bare fingers to probe open cranial wounds or break up blood clots.

"If there was an opening in the skull they would poke a finger into the wound and feel around, exploring for clots and bone fragments," Kushner said, adding that nearly every Civil War soldier with a gunshot wound subsequently suffered from infection. "We do not know how the ancient Peruvians prevented infection, but it seems that they did a good job of it. Neither do we know what they used as anesthesia, but since there were so many (cranial surgeries) they must have used something -- possibly coca leaves. Maybe there was something else, maybe a fermented beverage. There are no written records, so we just don't know."

Whatever their methods, ancient Peruvians had plenty of practice. More than 800 prehistoric skulls with evidence of trepanation -- at least one but as many as seven telltale holes -- have been found in the coastal regions and the Andean highlands of Peru, the earliest dating back to about 400 B.C. That's more than the combined total number of prehistoric trepanned skulls found in the rest of the world. Which is why Verano devoted an entire book, Holes in the Head -- The Art and Archeology of Trepanation in Ancient Peru, to the 800-plus skulls, most of which were collected from burial caves and archaeological digs in the late 1800s and early 1900s and reside in museums and private collections today.

It's also why Kushner, a medical history buff and Tulane alumnus, jumped at the chance to join Titelbaum in co-authoring one of the book's chapters, "Trepanation from the Perspective of Modern Neurosurgery," and continues to research the subject.

Published in 2016, the book analyzes the techniques and survival rates of trepanation in Peru through the demise of the Incan Empire in the early 1500s. The researchers gauged survival by classifying the extent of bone remodeling around the trepanned holes, which indicates healing. If there was no evidence of healing the researchers assumed the patient died during or within days of the surgery. If the margins of the trepanation openings showed extensive remodeling, they considered the operation successful and the patient long-lived.

Those classifications, Kushner, Verano and Titelbaum reported in the World Neurosurgery paper, show how ancient Peruvians significantly refined their trepanation techniques over the centuries. They learned, for example, not to perforate the protective membrane surrounding the brain -- a guideline Hippocrates codified in ancient Greece at about the same time, 5th century, B.C., that trepanning is thought to have begun in ancient Peru.

The long-term survival rates from such "shallow surgeries" in Peru during those early years, from about 400 to 200 B.C., proved to be worse than those in the Civil War, when about half the patients died. But, from 1000 to 1400 A.D., survival rates improved dramatically, to as high as 91 percent in some samples, to an average of 75 to 83 percent during the Incan period, the study showed.

"Over time, from the earliest to the latest, they learned which techniques were better, and less likely to perforate the dura," said Kushner, who has written extensively about modern-day neurosurgical outcomes. "They seemed to understand head anatomy and purposefully avoided the areas where there would be more bleeding. They also realized that larger-sized trepanations were less likely to be as successful as smaller ones. Physical evidence definitely shows that these ancient surgeons refined the procedure over time. Their success is truly remarkable."

Almost as remarkable is how, by the end of World War I, cranial surgery evolved into the distinct profession of neurosurgery, which continues to improve our understanding of brain anatomy, physiology and pathology. As Kushner notes, today's neurosurgeons regularly cut into the brain to remove tumors and blood clots, reduce intracranial pressure from massive strokes and trauma, repair vascular and structural anomalies and treat a myriad of other complex problems -- with great success.

Read more at Science Daily

Improved ape genome assemblies provide new insights into human evolution

Gorillas, like these two western lowland gorillas, are among the great apes. High resolution, comparative analysis of great ape genome assemblies is providing new insights into primate evolution, including human species.

New, higher-quality assemblies of great ape genomes have now been generated without the guidance of the human reference genome. The effort to reduce "humanizing" discovery bias in great ape genomes provides a clearer view of the genetic differences that arose as humans diverged from other primates.

In the June 8 issue of Science, researchers report on improved orangutan and chimpanzee genomes that were built from scratch using long-read PacBio sequencing and long-range mapping technology. The highly contiguous, newly assembled genomes present a better resource for novel gene discovery and high-resolution comparative genomics amongst the great apes.

The multi-institutional project, involving more than 40 scientists at a dozen research centers, was led by Zev N. Kronenberg and Evan Eichler, a Howard Hughes Medical Institute investigator in the Department of Genome Sciences at the University of Washington School of Medicine. Kronenberg is now a senior computational biologist at Phase Genomics.

The scientists note that many of the genetic differences between humans and other apes were not recognized when their genomes were first compared. Areas of rapid structural change were still nebulous in those early draft genome assemblies. This made them difficult to compare and limited the discovery of the functional differences that distinguish humans from other apes.

By coupling long-read sequence assembly with a hybrid genome scaffolding approach, the researchers resolved the majority of gaps in the ape genomes. Some of these gaps contained genes, which are now correctly annotated in the new genomes. To better understand the gene structures, the authors complemented this effort by sequencing more than 500,000 full-length genes from each species.

The newest investigation provides the most comprehensive catalog of genetic variants that were gained or lost on different ape lineages. Some of these variants affect how genes are differentially expressed among humans and apes.

The researchers examined the possible influence of some of the genetic variants and gene function regulators on such areas as human and ape dietary differences, anatomy, and brain formation.

The research team's comparative analysis of human and great ape genomes also included a gorilla assembly, a new assembly of an African human genome, and a human haploid hydatidform mole assembly. (Because they contain only half of the paired human chromosomes, studies of these rare human growths help tell similar duplicated genes apart.) All the genomes were sequenced and assembled using the same process.

Additionally, the researchers studied brain organoids -- laboratory-grown tissues coaxed from stem cells of apes or humans and forming a simplified version of organ parts. These brain proxies were examined to try to understand how differences in gene expression during brain development in humans and chimps might account for chimps' smaller brain volume, which is three times less than human brain volume. There are also significant dissimilarities in cortical structures in human and chimp brains.

The researchers observed in the organoids that certain genes, particularly those in cells that are like the progenitors of radial glial neurons, are down-regulated in humans compared to chimps. Those genes are more likely to have lost segments of DNA specifically in the human branch important in regulating their expression.

The scientists said that this finding is consistent with a "less is more" hypothesis proposed in the 1990s by now-retired UW School of Medicine genome sciences professor Maynard Olson and his colleagues. The hypothesis proposes that the loss of functional elements contributes to critical aspects of human evolution.

On the other hand, certain human genes appear to be linked to up-regulation for neural progenitors and excitatory neurons in the nervous system. These genes are more likely to have gained additional copies in the human species, compared to other apes, through a process of gene duplication.

The researchers said that their recent findings fit with their previous studies showing that the genomes of the common ancestral lineage for African great apes likely underwent an expansion of segmental duplication more than 10 million years ago. These repeats of sections of the genetic code may have made great ape genomes particularly prone to deletion and duplication events, thereby accelerating the rate of mutations with major consequences that helped drive the evolution of ape species.

Other discoveries reported in this Science paper stem from an investigation into the origin of a fossil virus, similar to present day retroviruses, that is thought to have been present in the genome of the common ancestor of all African apes. The high quality sequence helped identify the "source PtERV1," common to chimpanzees and gorillas. Modern day chimpanzees and gorillas carry hundreds of PtERV1 retroviral insertions that appear to have originated from this source that never made it into the human genome. The "source PtERV1" was overlooked in the earlier draft genomes because it mapped to repeat-rich gaps.

In other aspects of this project, the comparison of the gorilla and human genome assemblies identified a new gorilla sequence inversion near an important gene that controls penile spine morphology, which humans lack. These small, skin surface bumps occur on apes and some other mammals.

Humans also underwent the deletion of some genes involved in the synthesis of fatty acids. Some genetic changes related to dietary metabolism were identified in this project. These may have played a role relevant to the evolution of ape species. Great ape diets range from keeping strictly vegetarian to eating almost anything.

The researchers on this study predict that more advanced, long-range sequencing and mapping technologies, and even longer-read sequencing, will assist in increasing knowledge on the evolutionary journey taken by the great apes and our human ancestors. The scientists caution that the ape genomes and their work on them are not yet complete because the genome assemblies are still missing other larger, more complex structural variations that cannot yet be assembled.

Read more at Science Daily

'Monstrous' new Russian saber-tooth fossils clarify early evolution of mammal lineage

The skull of Nochnitsa geminidens, a new species of gorgonopsian discovered in the Permian of Russia.

Fossils representing two new species of saber-toothed prehistoric predators have been described by researchers from the North Carolina Museum of Natural Sciences (Raleigh, USA) and the Vyatka Paleontological Museum (Kirov, Russia). These new species improve the scientists' understanding of an important interval in the early evolution of mammals -- a time, between mass extinctions, when the roles of certain carnivores changed drastically.

Living mammals are descended from a group of animals called therapsids, a diverse assemblage of "protomammals" that dominated terrestrial ecosystems in the Permian Period (~299-252 million years ago), millions of years before the earliest dinosaurs. These protomammals included tusked herbivores, burrowing insectivores, and saber-toothed predators. The vast majority of Permian therapsids have been found in the Karoo Basin of South Africa, and as a result, the South African record has played an outsized role influencing scientists' understanding of protomammal evolution. Because of this, therapsid fossils from outside of South Africa are extremely important, allowing scientists to discern whether observed events in the protomammal fossil record represent global or merely regional patterns.

Recent expeditions by the Vyatka Paleontological Museum have collected a wealth of spectacularly-preserved Permian fossils near the town of Kotelnich along the Vyatka River in European Russia. These fossil discoveries include the remains of two previously unknown species of predatory protomammals, newly described in the journal PeerJ by Christian Kammerer of the North Carolina Museum of Natural Sciences and Vladimir Masyutin of the Vyatka Paleontological Museum. The first of the two new species, Gorynychus masyutinae, was a wolf-sized carnivore representing the largest predator in the Kotelnich fauna. The second new species, Nochnitsa geminidens, was a smaller, long-snouted carnivore with needle-like teeth. Gorynychus belongs to a subgroup of protomammals called therocephalians ("beast heads"), whereas Nochnitsa belongs to a different subgroup called gorgonopsians ("gorgon faces").

Both new species are named after legendary monsters from Russian folklore, befitting their menacing appearances. Gorynychus is named after Zmey Gorynych, a three-headed dragon, and Nochnitsa is named after a malevolent nocturnal spirit. (Based on their relatively large eye sockets, it is likely that Nochnitsa and its relatives were nocturnal.)

Gorynychus and Nochnitsa improve scientists' understanding of ecosystem reorganization after the mid-Permian extinction (260 mya). Although not as well-known as the more devastating end-Permian mass extinction (252 mya, which nearly wiped out protomammals), the mid-Permian mass extinction also played a major role in shaping the course of protomammal evolution. In typical late Permian ecosystems, the top predators were giant (tiger-sized), saber-toothed gorgonopsians and therocephalians were generally small insectivores. In mid-Permian ecosystems, by contrast, these roles are reversed. At Kotelnich, the saber-toothed top predator Gorynychus is a therocephalian and the only gorgonopsians are much smaller animals.

"In between these extinctions, there was a complete flip-flop in what roles these carnivores were playing in their ecosystems -- as if bears suddenly became weasel-sized and weasels became bear-sized in their place," says Kammerer. The new species from Russia provide the first evidence that there was a worldwide turnover in predators after the mid-Permian extinction, and not just a localized turnover in South Africa.

Read more at Science Daily

First tetrapods of Africa lived within the Devonian Antarctic Circle

This is a full reconstruction of Waterloo Farm by Maggie Newman including Tutusius and Umzantsia.

The first African fossils of Devonian tetrapods (four-legged vertebrates) show these pioneers of land living within the Antarctic circle, 360 million years ago.

The evolution of tetrapods from fishes during the Devonian period was a key event in our distant ancestry. New-found fossils from the latest Devonian Waterloo Farm locality near Grahamstown in the Eastern Cape, South Africa, published today in Science, force a major reassessment of this event. "Whereas all previously found Devonian tetrapods came from localities which were in tropical regions during the Devonian, these specimens lived within the Antarctic circle," explains lead author, Dr Robert Gess of the Albany Museum in Grahamstown, and co-author Professor Per Ahlberg of Uppsala University in Sweden. The research was supported by the South African DST-NRF Centre of Excellence in Palaeosciences, based at the University of the Witwatersrand and the Millennium Trust.

The first African Devonian tetrapods

Two new species, named Tutusius and Umzantsia, are Africa's earliest known four-legged vertebrates by a remarkable 70 million years. The approximately metre-long Tutusius umlambo (named in honour of Archbishop Emeritus Desmond Tutu) and the somewhat smaller Umzantsia amazana are both incomplete. Tutusius is represented by a single bone from the shoulder girdle, whereas Umzantsia is known from a greater number of bones, but they both appear similar to previously known Devonian tetrapods. Alive, they would have resembled a cross between a crocodile and a fish, with a crocodile-like head, stubby legs, and a tail with a fish-like fin.

The Waterloo Farm locality (where the tetrapods were discovered) is a roadcut first revealed in 2016 after controlled rock-cutting explosions by the South African National Roads Agency (SANRAL) along the N2 highway between Grahamstown and the Fish River. This cutting exposed dark grey mudstones of the Witpoort Formation that represent an ancient environment of a brackish, tidal river estuary that contain abundant fossils of animals and plants.

The first tetrapod found outside of tropical regions

The real importance of Tutusius and Umzantsia lies in where they were found.

Devonian tetrapod fossils are found in widely scattered localities. However, if the continents are mapped back to their Devonian positions, it emerges that all previous finds are from rocks deposited in the palaeotropics -- between 30 degrees north and south of the equator. Almost all come from Laurussia, a supercontinent that later fragmented into North America, Greenland and Europe.

The much larger southern supercontinent, Gondwana, which incorporated present-day Africa, South America, Australia, Antarctica, and India, has hitherto yielded almost no Devonian tetrapods, with only an isolated jaw (named Metaxygnathus) and footprints, being found in eastern Australia. Because Australia was the northernmost part of Gondwana, extending into the tropics, an assumption developed that tetrapods evolved in the tropics, most likely in Laurussia. By extension it was assumed that movement of vertebrates from water onto land (terrestrialisation) also occurred in the tropics. Attempts to understand the causes of these major macroevolutionary steps therefore focussed on conditions prevalent in tropical water bodies.

The Waterloo Farm tetrapods not only come from Gondwana, but from its southernmost part: reconstructed to have been more than 70 degrees south, within the Antarctic circle. Abundant plant fossils show that forests grew nearby, so it wasn't frozen, but it was definitely not tropical and during winter it will have experienced months of complete darkness. This finding changes our understanding of the distribution of Devonian tetrapods. We now know that tetrapods occurred throughout the world by the Late Devonian and that their evolution and terrestrialisation could realistically have occurred anywhere.

Read more at Science Daily

NASA’s Curiosity Rover Detects Methane and Organic Material on Mars

This low-angle self-portrait of NASA's Curiosity Mars rover shows the vehicle at the site from which it reached down to drill into a rock target called "Buckskin" on lower Mount Sharp.

NASA announced on Thursday two discoveries which further the prospects that scientists might one day find evidence of life on Mars.

First, data from NASA’s Curiosity rover has shown for the first time that methane levels in the martian atmosphere have a seasonal cycle. Scientists analyzed three years of atmospheric measurements taken by Curiosity and found low, background levels of methane that rose during summer in the northern hemisphere.

Also, scientists detected organic material preserved in rocks in Gale Crater, which is thought to be an ancient lakebed. The find suggests the planet could have supported ancient life.

The research has been published in the journal Science.

Chris Webster of NASA’s Jet Propulsion Laboratory said the methane discovery showed a discernible pattern in seasonal concentrations of the gas.

“We see a low background level of methane from winter to summer,” he said, “but the seasonal cycle changes by a factor of three, which is a huge change, and was completely unexpected.”

The methane could come from a biological source, but is likely stored in crystals called clathrates, which release the methane into the atmosphere during warmer summer weather.

“The detection of methane is always exciting because 95 percent of Earth’s methane is produced by biology, and so there has always been this interest in Mars methane” Webber said. “Our data shows that something is happening today that is producing it.”

Curiosity has detected seasonal changes in methane at Gale Crater using its SAM instrument.

Scientists first detected methane on Mars in 1999. Then, in 2014, Curiosity detected methane spikes, but the fluctuation in methane levels didn’t appear to fit a pattern.

Webber told Seeker the latest announcement is different than past methane discoveries.

“Now we’ve measured a consistent background level, with seasonal spikes of methane,” he said. “The spikes are very important, because the change is so dramatic, some process is causing large pulses of the gas being released.”

The methane concentrations ranged from 0.24 to 0.65 parts per billion.

The organic material detected by Curiosity, according to Jen Eigenbrode of NASA’s Goddard Space Flight Center, had been preserved in martian rocks for over 3 billion years.

Though the molecules are organic, the find doesn’t confirm the existence of life on Mars.

“Curiosity has not determined the source of the organic molecules,” said Eigenbrode. “And we have not determined whether it contains a record of ancient life, or was food for life. But it does give us chemical clues to planetary conditions and processes.”

The source of the organic material could have a meteorite crashing into the Red Planet, for example.

Curiosity has discovered ancient organic molecules in Gale Crater.

Eigenbrode said the molecules are amazingly robust. They were found close to the surface and were exposed to ionizing radiation, which can degrade organics.

“We think they haven’t changed over time, as this form of organic matter is resistant to changes,” she said. “But if life was on early Mars and other conditions were favorable, this means the organic biosignatures would be preserved.”

A drill on the Curiosity rover made a 5 centimeter hole in mudstones in Gale Crater at sites called Mojave and Confidence Hills. The rover then heated the rock samples to over 900 degrees Fahrenheit (500 degrees Celsius) and analyzed the molecules that were released. The process revealed the presence of several organic molecules, including carbon, thiophenes, benzene, toluene, and small carbon chains, such as propane or butene.

Like the methane discovery, NASA had also announced in 2014 the detection of organic molecules.

“In 2014, we reported the detection of chlorinated molecules, which is a significant discovery,” Eigenbrode told Seeker. “We had hoped we would find it with the Viking landers in the 1970’s, but we didn’t. While Curiosity’s first detection in 2014 was not what you typically find in natural samples, it did give us a lot of motivation to keep looking because we thought there had to be other layers of organic molecules.”

Read more at Seeker

Scientists use 4D scanning to predict behavior of volcanoes

A sample of magma with the composition of the 2001 Etna eruption after 2 hours of crystallisation during an experiment on a synchrotron beamline.

Scientists are using the latest in 4D technology to predict the behaviour of lava flows and its implications for volcanic eruptions.

The results explain why some lava flows can cover kilometres in just a few hours, whilst others travel more slowly during an eruption, highlighting the hazard posed by fast-moving flows which often pose the most danger to civilian populations close to volcanoes.

The research, which is being led by The University of Manchester, is studying the processes which happen during crystallisation in basaltic magmas using 4D synchrotron X-ray microtomography. It is the first time this kind of 4D scanning technology has been used for investigating crystallisation during volcanic eruptions and for simulating the behaviour of a natural lava flow. The study was recently published in Nature Scientific Reports.

The team, led by Prof Mike Burton, Chair of Volcanology at the University, monitored crystallisation in magmas, a fundamental process that drives eruptions and controls different kinds of volcanic activity. Using this new and novel approach and technology they can, for the first time, watch the crystals grow in 3D in real-time, simulating the behaviour of lava flows once a volcano has erupted. The process is similar to scenes recently witnessed at Kilauea in Hawaii.

Prof Burton explains: "During volcanic eruptions small crystals grow within magma. These crystals can greatly change the way magma flows. Simply put, the more crystals there are the slower the eruption will be which also reduces the speed and distance travelled by lava flows."

"The fewer crystals present in the lava means the eruption will speed up, potentially becoming more powerful and devastating. Our research and this new approach open an entirely new frontier in the study of volcanic processes." To study the rate of crystal growth the team set up a sample from a real eruption in a high temperature cell, before performing X-ray CAT scans whilst controlling the temperature of the magma. This allowed the team to visualise the formation and growth of crystals, and measure how quickly they grew.

Using this method and technology the researchers can collect hundreds of 3D images during a single experiment. This data is then used in complex, numerical models to fully characterise the behaviour of volcanic eruptions more accurately.

Dr Margherita Polacci, from Manchester's School of Earth and Environmental Sciences, and study's lead author, said: "Being able to more accurately predict the behaviour of lava flows could also allow us to help relevant safety agencies devise and develop new safety strategies and actions when dealing with eruptions in populated areas."

Read more at Science Daily

System with three Earth-sized planets discovered

Artistic simulation of a planetary system composed by three rocky planets with the same size of the Earth.

The information about these new exoplanets has been obtained from the data collected by the K2 mission of NASA's Kepler satellite, which started in November 2013. The work, which will be published in the Monthly Notices of the magazine Royal Astronomical Society (MNRAS), reveals the existence of two new planetary systems detected from the eclipses they produce in the stellar light of their respective stars. In the research team led jointly by Javier de Cos at the University of Oviedo, and Rafael Rebolo at the IAC, participate, along with researchers from these two centres, others from the University of Geneva and the Gran Telescopio Canarias (GTC).

The first exoplanetary system is located in the star K2-239, characterized by these researchers as a red dwarf type M3V from observations made with the Gran Telescopio Canarias (GTC), at the Roque de los Muchachos Observatory (Garafía, La Palma). It is located in the constellation of the Sextant at 50 parsecs from the Sun (at about 160 light years). It has a compact system of at least three rocky planets of similar size to the Earth (1.1, 1.0 and 1.1 Earth radii) that orbit the star every 5.2, 7.8 and 10.1 days, respectively.

The other red dwarf star called K2-240 has two super-Earth-like planets about twice the size of our planet. Although the atmospheric temperature of red dwarf stars, around which these planets revolve, is 3,450 and 3,800 K respectively, almost half the temperature of our Sun. These researchers estimate that all planets discovered will have temperatures superficial tens of degrees higher than those of the planet Earth due to the strong radiation they receive in these close orbits to their stars.

Future observation campaigns with the new James Webb space telescope will characterize the composition of the atmospheres of the discovered planets. Spectroscopic observations with the ESPRESSO instrument, installed in the Very Large Telescope (VLT), of the European Southern Observatory (ESO), or with future spectrographs in the GTC or in new astronomical facilities, such as the ELT or the TMT, will be crucial to determine the masses, densities and physical properties of these planets.

The Gran Telescopio Canarias (GTC), installed at the Roque de los Muchachos Observatory (Garafía, La Palma) is part of the Singular Scientific and Technical Infrastructure network (ICTS) of Spain.

From Science Daily

The disc of the Milky Way is bigger than we thought

The coloured region is the previously known Galactic disk. The present work has extended its limits much farther away: there is a probability 99.7 percent or 95.4 percent respectively that there are disk stars in the regions outside the dashed/dotted circles. Yellow dot is the position of the Sun. Background Milky Way image from 'A Roadmap to the Milky Way'.

Spiral galaxies such as the Milky Way have discs which are really thin, in which the major fraction of their stars are found. These discs are limited in size, so that beyond certain radius there are very few stars left.

In our Galaxy we were not aware that there are stars in the disc at distances from the centre more than twice that of the Sun. This means that our own star was apparently orbiting at about half the galactic radius. However now we know that there are stars quite a bit further out, at more than three times this distance, and it is probable that some stars are at more than four times the distance of the Sun from the Galactic centre.

"The disc of our Galaxy is huge, around 200 thousand light years in diameter" says Martín López-Corredoira, a researcher at the IAC and the first author of the article recently published in the journal Astronomy & Astrophysics and whose authors come from both the IAC and the NAOC.

In broad terms we can think of galaxies like the Milky Way as being composed of a rotating disc, which includes spiral arms, and a halo, spherical in shape, which surrounds it. This piece of research has compared the abundances of metals (heavy elements) in the stars of the Galactic plane with those of the halo, to find that there is a mixture of disc and halo stars out to the large distances indicated.

The researchers came to these conclusions after make a statistical analysis of survey date from APOGEE and LAMOST, two projects which obtain spectra of stars to extract information about their velocities and their chemical compositions. "Using the metallicities of the stars in the catalogues from the high quality spectral atlases of APOGEE and LAMOST, and with the distances at which the objects are situated, we have shown that there is an appreciable fraction of stars with higher metallicity, characteristic of disc stars, further out than the previously assumed limit on the radius of the Galaxy disc" explains Carlos Allende, a researcher at the IAC and a co-author of this publication.

Read more at Science Daily

Jurassic diet: Why our knowledge of what ancient pterosaurs ate might be wrong

Restoration of the giant azhdarchid pterosaur Hatzegopteryx catching an unsuspecting dinosaur for supper. In addition to carnivory, azhdarchids have been hypothesized to have eaten fish, insects, fruits, hard-shelled organisms or a combination of them all.

Whenever we think about extinct animals we often imagine them eating their favourite meals, whether it be plants, other animals or a combination of both.

But are our ideas about extinct diets grounded within scientific reasoning, or are they actually little more than conjecture and speculation?

New research, published in Biological Reviews and led by a team of palaeobiologists from the University of Leicester, has revealed that the diets of pterosaurs are largely based on ideas that have been uncritically accepted for decades, or even centuries -- and may often be wrong.

The study shows that one group of extinct animals where our dietary knowledge is lacking are the pterosaurs; extinct flying reptiles who lived in the Mesozoic Period 215-66 million years ago.

The research involved a comprehensive analysis of the scientific literature, summarising over 300 statements from 126 studies about the diets of pterosaurs, and the types of evidence used to support ideas of what they ate.

The research shows the vast majority of ideas about pterosaur diet are based on inferences drawn from modern organisms and/or the environments in which pterosaur fossils are preserved. These are not always reliable.

Jordan Bestwick, a PhD student from the School of Geography, Geology and the Environment, and lead author of the study, said: "Working out the diets of extinct animals is vitally important for understanding how they fitted within their respective ecosystems, which can tell us about how present ecosystems function and may change in the future.

"Being able to robustly test ideas is a key attribute of the scientific process, and helps us fully understand what we can know about the lifestyles of extinct animals, and what we can never know."

Analysis reveals that over sixty percent of all hypotheses of pterosaur diet are based on simplistic anatomical comparisons between pterosaurs and modern organisms, particularly of the skulls and teeth. A key problem with this is that many of these interpretations are difficult, if not impossible, to test.

Jordan explained: "The potential range of pterosaur diets has been reviewed in the past but little attention has been paid to the evidence, if any, that support dietary interpretations. We realised that not only was it important to discover what we know about pterosaur diets, but to also find out how we know what we know about pterosaur diets.

"We find for some pterosaurs there is strong agreement among researchers as to their likely diet. Pteranodontids for example, which include one of the best known pterosaurs, Pteranodon, are almost unanimously agreed to have been fish feeders, an idea that is independently supported by multiple lines of evidence.

"In contrast, there is far less agreement as to what the giant azhdarchid pterosaurs ate. Azhdarchids can reach sizes of up to 10 metres or more in wingspan, like Hatzegopteryx, and there have been at least six different diets argued for these pterosaurs."

This is not to say there are no methods or techniques that yield reliable evidence for understanding diets in these extinct animals. Biomechanical analysis of how hard pterosaurs could bite, and flight modelling that predicts how pterosaurs may have foraged for food have proven useful for understanding what some pterosaurs may or may not have eaten.

However techniques like these are employed in a small minority of studies and as such, it is currently not possible to identify the biological reasons that might explain the range and diversity of pterosaurs diets.

Read more at Science Daily

The Gravity From Small Objects, Not Planet Nine, Explains Weird Orbits

Artist representation of Sedna

DENVER — Small but rowdy space rocks pushing and jostling one another may have created the unusual orbits some astronomers cite as the signature of the hypothesized "Planet Nine," a new study suggests.

To date, researchers have discovered more than 2,300 bodies in the cold, distant realm beyond Neptune's orbit. The huge number of these trans-Neptunian objects (TNOs) makes it computationally intensive to model the evolution of their orbits. However, the new study suggests that the complex gravitational dances among TNOs can be enough to send some, such as the dwarf planet Sedna, onto odd and intriguing paths.

"The picture we have in our head is a lot of little moons floating around the solar system, interacting with comets," Ann-Marie Madigan, an assistant professor in the department of astrophysical and planetary sciences at the University of Colorado, Boulder (CU Boulder), said during a news conference today June 4.

Madigan and CU Boulder undergraduate student Jacob Fleisig presented the results here at the 232nd meeting of the American Astronomical Society, in Denver.

No need for Planet Nine?

The Kuiper Belt, the region immediately beyond Neptune, harbors TNOs of many sizes. The largest is Pluto, which was discovered more than 60 years before any of the others.

Some TNOs are "detached objects," which orbit so far from the sun that they're not appreciably affected by the gravity of Neptune or any other known planet. Perhaps the most famous of these is Sedna, which takes 11,400 years to make a single orbit and never comes closer to the sun than 20 times farther out than Pluto.

In 2016, astronomers Konstantin Batygin and Mike Brown announced that a distant undiscovered planet could have created the unusual signatures of some TNO orbits in the Kuiper Belt and sent Sedna and other detached objects out to even more distant realms. Batygin and Brown calculated that this world, dubbed Planet Nine, may be 10 times more massive than Earth and orbit the sun about 20 times farther away than Neptune does.

But not everybody is on board with the Planet Nine hypothesis. The skeptics include Madigan and Fleisig, who, along with study co-author Alexander Zderic, a UC Boulder graduate student, think they've found an alternate solution to the weird orbital signatures.

According to the researchers' simulations, the TNOs move like hands on a clock, with the most massive objects moving slowly, like the hour hand, and the smaller ones ticking along quickly, like the minute hand. The result is that the smaller bodies pile up quickly — and their accumulated gravity is strong enough to reshape the paths of larger TNOs that get close.

Eventually, the larger chunks wind up in extreme orbits, just like Sedna.

"They are what's causing this detachment, and not an unseen ninth planet," Fleisig said during the news conference.

The gravity of the situation

If this is the answer to the TNO puzzle, why hasn't anyone else noticed? Madigan and Fleisig said the problem is one of scale. It's computationally expensive to include a mass for each of the thousands of TNOs, so most simulations leave them massless, which negates how they interact gravitationally.

"The crucial difference is to include their mass in the simulation," Madigan told Space.com.

The researchers didn't add mass to all of the TNOs, only to about 400. But that was enough to send the most massive objects into bizarre orbits.

The collective-gravity hypothesis isn't a silver bullet, however. For example, there's still "clustering in pomega," which Madigan described as the odd fact that the orbits of the detached objects all tilt the same way.

"Planet Nine explains this really well, and we do not," Madigan said.

Ironically, while the new research discounts the need for an undiscovered planet, it requires the presence of thousands of smaller unseen objects.

"The handful we've seen is not enough," Fleisig said.

Madigan told Space.com that the early solar system was filled with enough debris to build up tens of Earths, but in far smaller pieces. Because most of the objects are modeled massless, most studies eject the bulk from the solar system. Adding mass means that more of that material could have stuck around, their smaller size keeping them from being detected.

"The objects we've seen so far are just the tip of the iceberg," Fleisig said.

While the small size of most TNOs makes them a challenge to detect, their motion makes it even harder. Usually, the larger an object is, the easier it is to discover. But because the largest objects are hurled into the most eccentric orbits, they become more difficult to find, the researchers said.

In addition, the presence of the small handful already spotted suggests a larger population, Madigan said.

"If there are only 10 out there, and we detected 10, it's bizarrely lucky," she said.

Death to the dinosaurs

The gravitational interactions among TNOs may also explain another strange event: the extinction of the nonavian dinosaurs about 65 million years ago.

Previous studies have suggested that mass extinctions may occur with regularity, and some researchers have linked this perceived periodicity to pulses of comet or asteroid strikes. What could cause a cyclical rain of death from above? Other researchers have cited dark matter or the sun's hypothesized unseen companion star, Nemesis, as candidates. (Nemesis has never been spotted and is dismissed by most scientists.)

Madigan called this impact-extinction-cycle idea "geology's Planet Nine" — a nebulous connection she said is under debate in geologic circles.

Read more at Seeker

You talking to me? Scientists try to unravel the mystery of 'animal conversations'

Crows, Corvus corone, conversing on the ice.

African elephants like to rumble, naked mole rats trade soft chirps, while fireflies alternate flashes in courtship dialogues.

Welcome to the weird and wonderful world of 'animal conversations'.

An international team of academics undertook a large-scale review of research into turn-taking behaviour in animal communication, analysing hundreds of animal studies.

Turn-taking, the orderly exchange of communicative signals, is a hallmark of human conversation and has been shown to be largely universal across human cultures.

The review, a collaboration between the Universities of York and Sheffield, the Max Planck Institute for Evolutionary Anthropology in Germany, and the Max Planck Institute for Psycholinguistics in the Netherlands, reveals that this most human of abilities is actually remarkably widespread across the animal kingdom.

While research on turn-taking behaviour is abundant, beginning more than 50 years ago with studies of the vocal interactions of birds, the literature is currently fragmented, making rigorous cross-species comparisons impossible.

Researchers who study turn-taking behaviours in songbirds, for example, speak of "duets" whereas those who study some species of monkeys note their "antiphonal calls."

One of the most noteworthy aspects of turn-taking behaviour across all species, humans included, is its fine timing.

In some species of songbird, for example, the latency between notes produced by two different birds is less than 50 milliseconds.

Other species are considerably slower; for example, sperm whales exchange sequences of clicks with a gap of about two seconds between turns. Humans lie somewhere in between, with gaps of around 200 milliseconds between turns at talk in conversation.

The authors of the study propose that systematic cross-species comparisons of such turn-taking behaviour may shed new light on the evolution of language.

The academics propose a new comparative framework for future studies on turn-taking.

One of the authors, Dr Kobin Kendrick, from the University of York's Department of Language and Linguistic Science, said: "The ultimate goal of the framework is to facilitate large-scale, systematic cross-species comparisons.

"Such a framework will allow researchers to trace the evolutionary history of this remarkable turn-taking behaviour and address longstanding questions about the origins of human language."

Read more at Science Daily

As solar wind blows, our heliosphere balloons

An illustration depicting the layers of the heliosphere.

What happens when the solar wind suddenly starts to blow significantly harder? According to two recent studies, the boundaries of our entire solar system balloon outward -- and an analysis of particles rebounding off of its edges will reveal its new shape.

In late 2014, NASA spacecraft detected a substantial change in the solar wind. For the first time in nearly a decade, the solar wind pressure -- a combined measure of its speed and density -- had increased by approximately 50 percent and remained that way for several years thereafter. Two years later, the Interstellar Boundary Explorer, or IBEX, spacecraft detected the first sign of the aftermath. Solar wind particles from the 2014 pressure increase had reached the edge of the heliosphere, neutralized themselves, and shot all the way back to Earth. And they had a story to tell.

In two recent articles, scientists used IBEX data along with sophisticated numerical models to understand what these rebounding atoms can tell us about the evolving shape and structure of our heliosphere, the giant bubble carved out by the solar wind.

"The results show that the 2014 solar wind pressure increase has already propagated from the Sun to the outer heliosphere, morphing and expanding our heliosphere's boundaries in their closest direction," said David McComas, the principal investigator for the IBEX mission at Princeton University in Princeton, New Jersey. "IBEX data pouring in over the next few years will let us chart the expansion and evolving structure of the other portions of the heliosphere's outer boundaries."

From the Sun to the edge of the solar system -- and back At the crux of the story are energetic neutral atoms -- high-energy particles produced at the very edge of our solar system.

As the solar wind flows out from the Sun at supersonic speeds, it blows up a bubble known as the heliosphere. The heliosphere encases all the planets in our solar system and much of the space beyond them, separating the domain of our Sun from that of interstellar space.

But the solar wind's journey from the Sun is not a smooth ride. On its way to the very edge of our heliosphere, known as the heliopause, the solar wind passes through distinct layers. The first of these is known as the termination shock.

Before passing the termination shock, the solar wind expands rapidly, largely unimpeded by outside material.

"But at the termination shock, roughly 9.3 billion miles away from us in every direction, the solar wind slows down abruptly. Beyond this point it continues to move outwards, but it is much hotter," said Eric Zirnstein, lead author of one of the papers at Princeton.

Once beyond the termination shock, solar wind particles enter a special limbo zone known as the heliosheath. While the termination shock is essentially spherical, the edges of the heliosphere are thought to describe more of an arc around the Sun as it moves through space -- closer to the Sun toward the front, and extending long behind it, not unlike a comet with a tail. Along these boundaries, solar wind particles mix with particles from interstellar space. Collisions are inevitable: the hot, electrically-charged solar wind particles bang into the slower, colder neutral atoms from interstellar space, stealing an electron and becoming neutral themselves.

"From there they go travelling ballistically through space, and some make it all the way back to Earth," Zirnstein said. "These are the energetic neutral atoms that IBEX observes."

In late 2016, when IBEX's energetic neutral atom imager began to pick up an unusually strong signal, Professor McComas and his team set out to investigate its cause. Their findings are reported in an article published on March 20, 2018, in the Astrophysical Journal Letters.

The energetic neutral atoms were coming from about 30 degrees south of the interstellar upwind direction, where the heliosheath was known to be closest to Earth.

To quantify its connection to the 2014 solar wind pressure increase, McComas and his team turned to numerical simulations, working out how such a pressure increase could affect the energetic neutral atoms that IBEX observes.

"These types of simulations involve a model for the physics, which then gets turned into equations, which are in turn solved on a supercomputer," said Jacob Heerikhuisen, a coauthor on both papers at the University of Alabama in Huntsville.

Using computer models, the team simulated an entire heliosphere, jolted it with a solar wind pressure increase, and let it run the numbers. The simulation completed a story only hinted at by the data.

According to the simulation, once the solar wind hits the termination shock it creates a pressure wave. That pressure wave continues on to the edge of the heliosphere and partially rebounds backwards, forcing particles to collide within the (now much denser) heliosheath environment that it just passed through. That's where the energetic neutral atoms that IBEX observed were born.

The simulations provided a compelling case: IBEX was indeed observing the results of the 2014 solar wind pressure increase, more than two years later.

But the simulation didn't stop there. It also revealed that the 2014 solar wind pressure increase would, over time, continue to blow up the heliosphere even further. Three years after the solar wind pressure increase -- by the time the article was published -- the termination shock, the inner bubble within the heliosphere, should expand by seven astronomical units, or seven times the distance from Earth to the Sun. The heliopause, the outer bubble, should expand by two astronomical units, with an additional two the following year.

In short, by cranking up the pressure of the solar wind, our heliosphere today is bigger than it was just a few years ago.

The heliosphere's new shape

McComas and colleagues studied the very first signs of the 2014 solar wind pressure increase. But watching the data over the coming years may tell us even more -- this time about the evolving shape of our heliosphere.

"There have been many studies, some from quite a while ago, predicting what the heliosphere shape should look like," Zirnstein, the lead author of the paper, reports. "But it's still very much up for debate in the modelling community. We're hoping that the 2014 solar wind pressure increase could help with that."

Using the same data and simulations used in the previous paper, Zirnstein and colleagues ran the clock forward, modeling the heliosphere eight years after the 2014 solar wind pressure increase. The results describe not only the past, but also model the future. The paper was published on May 30, 2018, in The Astrophysical Journal.

"What we think we should see in the near future is a ring, expanding across the sky, marking the change in energetic neutral atom flux over time," said Zirnstein. "This ring expands away from the point of initial contact in the outer heliosphere, towards the directions of the heliotail."

Although the initial signal detected by IBEX in 2016 was a solid circle, it won't stay that way. As the 2014 solar wind reaches points of the heliopause further and further away, they take longer to bounce back, like an echo off of a far-away wall. The heliosphere's rounded shape causes this echo to reflect back in the form of a ring.

But the key finding came from watching the ring as it expands.

In their simulation, Zirnstein and colleagues found that the precise rate at which the ring expands depended in part on the distances between the various layers of the heliosphere: the termination shock, the heliopause, and the part of the heliosheath where the energetic neutrals were produced. Zirnstein realized he had found a new way to measure the size and shape of the heliosphere.

"We could estimate the distances to the different boundaries of the heliosphere just by looking at this ring changing over time in the sky," said Zirnstein.

Zirnstein and colleagues used their simulated heliosphere to run a test study. By measuring the rate of expansion of the ring (and plugging it into the right equations), they could accurately reproduce the distances to key structures within their simulated heliosphere. Since they knew what those distances were in their simulation, they could check their work -- validating that the technique got the right answers and should be accurate when applied to the real heliosphere.

Deformities in the ring -- deviations from a perfect circle -- could also reveal asymmetries in the heliosphere's overall shape. "It depends on how symmetric or asymmetric the heliosphere is," Zirnstein added. "If the heliosphere was an ideal 'comet shape,' the ring should expand symmetrically over time. But in reality that's probably not going to happen -- we'll have to wait and see what IBEX tell us."

Zirnstein expressed excitement about the possibility of learning the true shape of the heliosphere.

"Over the next few years with more IBEX data, my hope is that we can build a 3D picture of the shape of the heliosphere," said Zirnstein.

The results of these two studies have important practical implications. "Connecting changes in the Sun with energetic neutral atom observations will help us understand long term changes in the hazardous conditions for space radiation environment -- a sort of space climate as opposed to space weather," McComas said. "As the solar wind blows more and less hard, and our solar bubble expands and contracts, which directly affects the amount of cosmic rays that can enter the heliosphere, potentially endangering astronauts on long duration spaceflights."

Read more at Science Daily

New data-mining technique offers most-vivid picture of Martian mineralogy

A panorama of Gale crater on Mars taken from Vera Rubin ridge.

A team of scientists led by Carnegie's Shaunna Morrison and including Bob Hazen have revealed the mineralogy of Mars at an unprecedented scale, which will help them understand the planet's geologic history and habitability. Their findings are published in two American Mineralogist papers.

Minerals form from novel combinations of elements. These combinations can be facilitated by geological activity, including volcanoes and water-rock interactions. Understanding the mineralogy of another planet, such as Mars, allows scientists to backtrack and understand the forces that shaped their formation in that location.

An instrument on NASA's Mars Curiosity Rover called the Chemistry and Mineralogy Instrument, or CheMin, is the first tool of its kind ever to operate on another planet. But there are limitations to how much it can tell scientists about the Red Planet's minerals -- how they formed and what they can illuminate about Martian history.

But Morrison found a way to glean even more information from the CheMin data, information which paints a detailed picture of the minerals the rover encountered on Mars.

CheMin is able to discern what types of minerals exist on Mars and in what proportions they are found. But until this latest work from Morrison, scientists didn't have the calibration capabilities to measure the precise composition or crystal chemistry of those minerals from CheMin data alone. For example, CheMin told Earth-bound scientists that certain types of feldspar exist on Mars, but it did not provide the level of detail that can give mineralogists vital clues about the conditions under the feldspars formed.

Crystals, by definition, have a long-range repetitive structure. The smallest unit of the geometry of this crystal lattice is called the unit cell, comprised of repeating atomic units. Morrison realized that because the unit cell dimensions for minerals found in the 13 samples CheMin took of the soils, sandstones, and formations of Mar's Gale Crater are known, she could use them as a key to unlock more information about the minerals sampled by CheMin.

"I scoured the literature, gathering and analyzing thousands of measurements of both mineral compositions and unit cell dimensions and then determined a mathematical connection between them," Morrison explained. "Once this relationship was established, it could be used to glean much more detail about the minerals in the Martian samples taken by CheMin."

For example, CheMin was able to measure that Mars' Gale Crater contains the minerals feldspar and olivine. Using Morrison's connection between unit cells and compositions, the team was able to determine how the composition of feldspar varies between the different sampling locations, which can offer information about its igneous origins. In addition, the percentage of magnesium found in olivine samples range from 52 to 72 percent, which when compared with Martian meteorites may offer information about aqueous alteration of the material.

"Thanks to Shaunna's creative approach, we have improved CheMin's resolution by an order of magnitude," Hazen explained. "The result is the most vivid picture yet of the mineralogy of another planet."

Read more at Science Daily

Microbiome differences between urban and rural populations start soon after birth

This graphical abstract illustrates factors that affect the fecal microbiome and metabolome of rural Bassa and urban individuals from Nigeria, including infants. The findings stress the loss of ancient signatures along with urbanization and support distinct trajectories of development of the intestinal ecosystem in early life, depending on human subsistence.

An analysis comparing the intestinal microbiomes of both infants and adults living in rural and urban areas of Nigeria has revealed that not only are there many differences in adults living in subsistence environments versus urban ones but also that these variations begin at a very young age. The study appears June 5 in the journal Cell Reports.

"We've always assumed that the microbiomes of infants were the same everywhere, and that differences came later in life," says senior author Silvia Turroni of the Department of Pharmacy and Biotechnology at the University of Bologna in Italy. "We were surprised to find that the microbiomes of infants living in rural areas were missing components that we have long believed were standard to all infant populations -- especially that they were essentially devoid of Bifidobacterium." Bifidobacterium dominates the microbiomes of Western infants and has been considered a key element to healthy growth and development.

Previous studies that have analyzed the microbiomes of rural, hunter-gatherer societies have generally compared them to distant urban populations in Europe or the United States. This study was unique in that it looked at rural and urban African people in the same geographic area. Urban populations in the study were drawn from four state capital cities in Nigeria and the national capital, Abuja.

"This research was specifically designed to fill in gaps of knowledge about the variation of the human gut microbiome, as well as the metabolome, in relation to subsistence patterns in geographically close populations," says first author Funmilola Ayeni of the Department of Pharmaceutical Microbiology at the University of Ibadan in Nigeria.

This study was also unique because it looked at both infant and adult microbiomes. For the purposes of this study, infants were defined as children up to age three. Unexpectedly, the investigators found that infants living in rural areas had microbiome profiles that were overall more diverse and more like those of adults.

The rural people included in the study, an agricultural society called the Bassa, consume a diet consisting of tubers, grains, and leafy soups, as well as untreated water. The urban diet contained processed foods and treated water but had more elements of a traditional Nigerian diet than what is seen in Western countries. Rural infants were given foods other than breast milk at a younger age than urban infants were.

Although it is only one factor, diet is an important component affecting the makeup of the intestinal microbiota. The researchers found that the rural population had a higher level of certain bacterial species that are important for digesting fiber. In addition, when metabolites in the samples were analyzed, rural populations had lower levels of amino acids and biogenic amines, suggesting a lower consumption of protein.

There were some drawbacks to the study. For one, the Bassa people usually don't know their exact ages. Also, data about gender were not collected for the Bassa who participated, so the researchers were not able to look at whether there were differences between the sexes.

Still, the findings were notable. "Studies like these have profound evolutionary relevance because they recall ways of life that have characterized human history, from the hunting and gathering of our Paleolithic ancestors to small-scale agriculture, to the postindustrial Western lifestyle," Turroni says.

Read more at Science Daily

Red tide fossils point to Jurassic sea flood

One of the dinoflagellate cysts, normally the cause of red tides in the sea, has been found in arid Australia.

Dinosaur-age fossilised remains of tiny organisms normally found in the sea have been discovered in inland, arid Australia -- suggesting the area was, for a short time at least, inundated by sea water 40 million years before Australia's large inland sea existed.

The fossils are the egg-like cysts of microorganisms known as dinoflagellates, best known for producing red tides or algal blooms that can turn the sea water blood red. The cysts rest on the sea floor before hatching new dinoflagellates.

Researchers at the University of Adelaide, in collaboration with geological consultancy MGPalaeo, discovered these microfossils in Jurassic rocks of south-western Queensland, near the town of Roma.

Described in the journal Palynology, the fossils have been dated to the late Jurassic period, 148 million years ago. This is a time when Australia was joined to Antarctica, and where dinosaurs roamed across ancient rivers, floodplains and swamps.

"We have plenty of evidence from the 110 million-year-old vast inland Eromanga Sea, which covered a large swathe of central, eastern Australia during the Cretaceous period (following on from the Jurassic)," says Dr Carmine Wainman, Postdoctoral Fellow in the University of Adelaide's Australian School of Petroleum.

"We've seen the opalised fossils sold in Adelaide's Rundle Mall, and the spectacular ancient marine reptiles on display in the South Australian Museum -- all from the later Cretaceous period.

"However, this new microfossil evidence from the same region suggests there was a short-lived precursor to this sea 40 million years earlier."

Dr Wainman believes these microfossils must have been brought inland by an incursion of sea water and then evolved quickly to adapt to the freshwater or brackish conditions as the sea waters slowly receded.

"There is no other feasible explanation for how they managed to reach the interior of the Australian continent when the ancient coastline was thousands of kilometres away," Dr Wainman says.

Read more at Science Daily

New insight into Earth's crust, mantle and outer core interactions

Earth's crust, mantle and outer core interactions.

A new study by the University of Liverpool, in collaboration with the Universities of Lancaster and Oslo, sheds light on a longstanding question that has puzzled earth scientists.

Using previously unavailable data, researchers confirm a correlation between the movement of plate tectonics on the Earth's surface, the flow of mantle above the Earth's core and the rate of reversal of the Earth's magnetic field which has long been hypothesised.

In a paper published in the journal Tectonophysics, they suggest that it takes around 120-130 million years for slabs of ancient ocean floor to sink (subduct) from the Earth's surface to a sufficient depth in the mantle where they can cool the core, which in turn causes the liquid iron in the Earth's outer core to flow more vigorously and produce more reversals of the Earth's magnetic field.

This study is the first to demonstrate this correlation using records and proxies of global rates of subduction from various sources including a continuous global plate reconstruction model developed at the University of Sydney. These records were compared with a new compilation of magnetic field reversals whose occurrence is locked into volcanic and sedimentary rocks.

Liverpool palaeomagnetist, Professor Andy Biggin, said: "Until recently we did not have good enough records of how much global rates of subduction had changed over the last few hundreds of millions of years and so we had nothing to compare with the magnetic records.

"When we were able to compare them, we found that the two records of subduction and magnetic reversal rate do appear to be correlated after allowing for a time delay of 120-130 million years for the slabs of ocean floor to go from the surface to a sufficient depth in the mantle where they can cool the core.

"We do not know for sure that the correlation is causal but it does seem to fit with our understanding of how the crust, mantle and core should all be interacting and this value of 120-130 million could provide a really useful observational constraint on how quickly slabs of ancient sea floor can fall through the mantle and affect flow currents within it and in the underlying core."

The magnetic field is generated deep within the Earth in a fluid outer core of iron and other elements that creates electric currents, which in turn produces magnetic fields.

The core is surrounded by a nearly 3,000 km thick mantle which although made of solid rock, flows very slowly (mm per year). The mantle produces convection currents which are strongly linked to movement of the tectonic plates but also affect the core by varying the amount of heat that is transferred across the core-mantle boundary.

The Earth's magnetic field occasionally flips its polarity and the average length of time between such flips has changed dramatically through Earth's history. For example, today such magnetic reversals occur on average four times per million years but one hundred million years ago, the field essentially stayed in the same polarity for nearly 40 million years.

Read more at Science Daily

Thank the moon for Earth's lengthening day

Image of Earth taken by the Apollo 8 astronauts on Dec. 22, 1968 as they became the first humans to circumnavigate the moon.

For anyone who has ever wished there were more hours in the day, geoscientists have some good news: Days on Earth are getting longer.

A new study that reconstructs the deep history of our planet's relationship to the moon shows that 1.4 billion years ago, a day on Earth lasted just over 18 hours. This is at least in part because the moon was closer and changed the way Earth spun around its axis.

"As the moon moves away, the Earth is like a spinning figure skater who slows down as they stretch their arms out," explains Stephen Meyers, professor of geoscience at the University of Wisconsin-Madison and co-author of the study published this week [June 4, 2018] in the Proceedings of the National Academy of Sciences.

It describes a tool, a statistical method, that links astronomical theory with geological observation (called astrochronology) to look back on Earth's geologic past, reconstruct the history of the solar system and understand ancient climate change as captured in the rock record.

"One of our ambitions was to use astrochronology to tell time in the most distant past, to develop very ancient geological time scales," Meyers says. "We want to be able to study rocks that are billions of years old in a way that is comparable to how we study modern geologic processes."

Earth's movement in space is influenced by the other astronomical bodies that exert force on it, like other planets and the moon. This helps determine variations in Earth's rotation around and wobble on its axis, and in the orbit Earth traces around the sun.

These variations are collectively known as Milankovitch cycles and they determine where sunlight is distributed on Earth, which also means they determine Earth's climate rhythms. Scientists like Meyers have observed this climate rhythm in the rock record, spanning hundreds of millions of years.

But going back further, on the scale of billions of years, has proved challenging because typical geologic means, like radioisotope dating, do not provide the precision needed to identify the cycles. It's also complicated by lack of knowledge of the history of the moon, and by what is known as solar system chaos, a theory posed by Parisian astronomer Jacques Laskar in 1989.

The solar system has many moving parts, including the other planets orbiting the sun. Small, initial variations in these moving parts can propagate into big changes millions of years later; this is solar system chaos, and trying to account for it can be like trying to trace the butterfly effect in reverse.

Last year, Meyers and colleagues cracked the code on the chaotic solar system in a study of sediments from a 90 million-year-old rock formation that captured Earth's climate cycles. Still, the further back in the rock record he and others have tried to go, the less reliable their conclusions.

For instance, the moon is currently moving away from Earth at a rate of 3.82 centimeters per year. Using this present day rate, scientists extrapolating back through time calculated that "beyond about 1.5 billion years ago, the moon would have been close enough that its gravitational interactions with the Earth would have ripped the moon apart," Meyers explains. Yet, we know the moon is 4.5 billion years old.

So, Meyers sought a way to better account for just what our planetary neighbors were doing billions of years ago in order to understand the effect they had on Earth and its Milankovitch cycles. This was the problem he brought with him to a talk he gave at Columbia University's Lamont-Doherty Earth Observatory while on sabbatical in 2016.

In the audience that day was Alberto Malinverno, Lamont Research Professor at Columbia. "I was sitting there when I said to myself, 'I think I know how to do it! Let's get together!'" says Malinverno, the other study co-author. "It was exciting because, in a way, you dream of this all the time; I was a solution looking for a problem."

The two teamed up to combine a statistical method that Meyers developed in 2015 to deal with uncertainty across time -- called TimeOpt -- with astronomical theory, geologic data and a sophisticated statistical approach called Bayesian inversion that allows the researchers to get a better handle on the uncertainty of a study system.

They then tested the approach, which they call TimeOptMCMC, on two stratigraphic rock layers: the 1.4 billion-year-old Xiamaling Formation from Northern China and a 55 million-year-old record from Walvis Ridge, in the southern Atlantic Ocean.

With the approach, they could reliably assess from layers of rock in the geologic record variations in the direction of the axis of rotation of Earth and the shape of its orbit both in more recent time and in deep time, while also addressing uncertainty. They were also able to determine the length of day and the distance between Earth and the moon.

"In the future, we want to expand the work into different intervals of geologic time," says Malinverno.

The study complements two other recent studies that rely on the rock record and Milankovitch cycles to better understand Earth's history and behavior.

A research team at Lamont-Doherty used a rock formation in Arizona to confirm the remarkable regularity of Earth's orbital fluctuations from nearly circular to more elliptical on a 405,000 year cycle. And another team in New Zealand, in collaboration with Meyers, looked at how changes in Earth's orbit and rotation on its axis have affected cycles of evolution and extinction of marine organisms called graptoloids, going back 450 million years.

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Hats on for Easter Island statues

Restored statue platform with standing moai on the south coast of Rapa Nui. Note that one of the moai is adorned with a red scoria pukao.

How do you put a 13-ton hat on a giant statue? That's what a team of researchers is trying to figure out with their study of Easter Island statues and the red hats that sit atop some of them.

"Lots of people have come up with ideas, but we are the first to come up with an idea that uses archaeological evidence," said Sean W. Hixon, graduate student in anthropology, Penn State.

Rapa Nui -- Easter Island, Chile -- sits in the Southern Pacific Ocean more than 2,000 miles from Chile in South America. The island is about 15 miles long and 7.6 miles wide at its widest with an area of about 63 square miles. According to the researchers, the island was first inhabited in the 13th century by Polynesian travelers.

The statues, carved from volcanic tuff, came from one quarry on the island, while the hats, made of red scoria, came from a different quarry 7.5 miles away on the other side of the island.

Previous research by Carl P. Lipo, professor of anthropology, Binghamton University, and Terry Hunt, professor of anthropology and dean of the Honors College, University of Arizona, determined that the statues, which can be up to 33 feet tall and weigh 81 tons, were moved into place along well-prepared roads using a walking/rocking motion, similar to the way a refrigerator is moved.

"The statues were moved in a fashion using simple physics-based processes in a way that was elegant and remarkably effective," said Lipo. Not all statues made it to their final locations, and the fallen and/or broken ones showed that, to move them, the statues were carved so they leaned forward and were later leveled off for final placement.

The hats, with diameters up to 6.5 feet and weighing 13 tons, might have been rolled across the island, but once they arrived at their intended statues, they still needed to be lifted onto the statues' heads. The islanders probably carved the hats cylindrically and rolled them to the statues before further carving the hats to attain the final shapes, which vary from cylindrical to conical and which usually have a smaller cylindrical projection on the top. Chips of red scoria are found in the platform of some of the statue hat combinations.

"We were interested in figuring out the method of hat transport and placement of the hats that best agrees with the archaeological record," said Hixon.

The researchers took multiple photographs of many Rapa Nui hats to see what attributes of the hats were the same throughout. Using photogrammetry and 3-D imaging, they created images of the hats with all their details.

"We assumed they were all transported and placed in the same way," said Hixon. "So we looked for features that were the same on all the hats and all the statues."

The only features they found the same were indentations at the bases of the hats, and these indentations fit the tops of the statues' heads. If the hats had been slid in place on top of the statues, then the soft stone ridges on the margin of the indentations would have been destroyed. So the islanders must have used some other method.

Previous researchers suggested that the statues and the hats were united before they were lifted in place, but the remnants of broken or abandoned statues, and other evidence for walking the statues, indicates this was not the approach used and that the hats were most likely raised to the top of standing statues.

Many of the hats left around the island are much larger than those placed on statues.

"The best explanation for the transport of the pukao (hats) from the quarry is by rolling the raw material to the location of the moai (statues)," said Lipo. "Once at the moai, the pukao were rolled up large ramps to the top of a standing statue using a parbuckling technique." Parbuckling is a simple and efficient technique for rolling objects and is often used to right ships that have capsized. The center of a long rope is fixed to the top of a ramp and the two trailing ends are wrapped around the cylinder to be moved. The rope ends are then brought to the top where workers pull on the ropes to move the cylinder up the ramp.

Besides reducing the force needed to move the hats, this arrangement also makes it easier to stabilize the hat on the trip up because the hat typically will not roll back down the slope. The researchers report in the current issue of the Journal of Archaeological Science, that 15 or fewer workers could move the largest preform hats up the ramps.

Once the hat was at the top of the ramp, it could not simply be pushed into place because of the ridges on the margin of the hat base indentation. Rather, the researchers believe that the hats were tipped up onto the statues.

First the hat would be modified to its final form, some including a second, smaller cylindrical piece on top.

The hats could be rotated 90 degrees and then levered up with small wooden levers to sit on the statue tops, or the ramp could be slightly to the side, so that rotation in the small space at the top of the ramp would be unnecessary. Then the hat would simply be levered and pivoted on edge and into place.

The ramps were then disassembled and became the wings of the platform surrounding the statues.

"This is the first time anyone has systematically explored the evidence for how the giant hats were placed on the top of the heads of the massive statues of Easter Island," said Lipo. "Our work combines cutting-edge 3-D modeling with artifact analysis and models drawn from physics to arrive at the best answer."

Also working on this project were Ben McMorran, associate professor of physics, University of Oregon, and Terry L. Hunt, dean, Honors College, University of Arizona.

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