Ants, acorns and climate change

The Case Western Reserve biologists 'explore(d) the potential for parallel (and non-parallel) evolution of thermal tolerance across three cities using acorn ants as a model system' as these particular ants are 'highly sensitive to temperature, including in their development rate, running speed and thermal tolerance,' according to their paper.

The relatively swift adaptability of tiny, acorn-dwelling ants to warmer environments could help scientists predict how other species might evolve in the crucible of global climate change.

That's a big-picture conclusion from research into the some of the world's smallest creatures, according to evolutionary biologists at Case Western Reserve University.

More specifically, the scientists are comparing the adaptability of a certain species of ant raised in the "heat-island" microclimate of three U.S. cities to those in nearby cooler rural areas.

"What we're finding is the potential for ants -- and other animals, perhaps -- to evolve in response to anthropogenic (human-caused) climate change," said lead researcher Sarah Diamond, who first began peering into acorns to study the ants in 2015. The research so far has shown that the ants adapt to a hotter world in only about 20 generations, or about 100 years.

This comparatively lightning-fast evolutionary response is adding to scientists' understanding of evolutionary processes, in general, but also in understanding the effects of urbanization, said Diamond, the George B. Mayer Assistant Professor of Urban and Environmental Studies at the university.

"While we usually think of evolution as happening over thousands of years or more, we're finding that it is happening more rapidly in these cases," she said, "and that presents a unique opportunity to test the predictability and parallelism of evolutionary change."

The most recent study by Diamond and Ryan Martin, an assistant professor of biology at Case Western Reserve, was published in July in the Proceedings of the Royal Society B, a broad-scope biology journal.

Earlier research by the Case Western Reserve researchers was featured in a New York Times report and elsewhere and focused primarily on how "city ants and country ants" adapted in Cleveland and a nearby rural area.

The outcome of that earlier study was that ants from the city were more tolerant of heat than rural ants living in colonies about five degrees Fahrenheit cooler -- an adaptation that would have arisen only over the last century as the city became urbanized and warmer due to the heat island effect.

Different cities, mixed results

The new paper describes how the research was extended to two more cities, Cincinnati, Ohio and Knoxville, Tennessee, to test whether the ants would respond in "parallel" to urban heat islands.

The scientists added the two new sites to test whether the outcomes would be consistent, or whether each area is distinctive, and because "cities function as easily replicated warming experiments across the globe" due to the urban heat island effect, Diamond said.

The measurements: Urban ants were again more tolerant to heat but lost some of their tolerance to cold compared to their rural neighbors. The researchers also found that urban ant populations produced more "sexual reproductives" -- offspring who could, in turn, reproduce -- under warmer laboratory rearing temperatures that mimicked their city habitats; rural populations produced fewer.

This new result suggests that the urban ants are indeed adapting to city life: "Their increased tolerance for warm temperatures is helping them live in cities," Martin said.

In Cleveland and Knoxville, they did, but "Cincinnati is misbehaving," Diamond said with a laugh, noting that the city ants there did not show the same degree of adaptability.

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Water-worlds are common: Exoplanets may contain vast amounts of water

Exoplanets similar to Earth.

Scientists have shown that water is likely to be a major component of those exoplanets (planets orbiting other stars) which are between two to four times the size of Earth. It will have implications for the search of life in our Galaxy. The work is presented at the Goldschmidt conference in Boston.

The 1992 discovery of exoplanets orbiting other stars has sparked interest in understanding the composition of these planets to determine, among other goals, whether they are suitable for the development of life. Now a new evaluation of data from the exoplanet-hunting Kepler Space Telescope and the Gaia mission indicates that many of the known planets may contain as much as 50% water. This is much more than the Earth's 0.02% (by weight) water content.

"It was a huge surprise to realize that there must be so many water-worlds," said lead researcher Dr Li Zeng (Harvard University),

Scientists have found that many of the 4000 confirmed or candidate exoplanets discovered so far fall into two size categories: those with the planetary radius averaging around 1.5 that of the Earth, and those averaging around 2.5 times the radius of the Earth.

Now a group of International scientists, after analyzing the exoplanets with mass measurements and recent radius measurements from the Gaia satellite, have developed a model of their internal structure.

"We have looked at how mass relates to radius, and developed a model which might explain the relationship," said Li Zeng. The model indicates that those exoplanets which have a radius of around x1.5 Earth radius tend to be rocky planets (of typically x5 the mass of the Earth), while those with a radius of x2.5 Earth radius (with a mass around x10 that of the Earth) are probably water worlds."

"This is water, but not as commonly found here on Earth," said Li Zeng. "Their surface temperature is expected to be in the 200 to 500 degree Celsius range. Their surface may be shrouded in a water-vapor-dominated atmosphere, with a liquid water layer underneath. Moving deeper, one would expect to find this water transforms into high-pressure ices before we reaching the solid rocky core. The beauty of the model is that it explains just how composition relates to the known facts about these planets."

Li Zeng continued, "Our data indicate that about 35% of all known exoplanets which are bigger than Earth should be water-rich. These water worlds likely formed in similar ways to the giant planet cores (Jupiter, Saturn, Uranus, Neptune) which we find in our own solar system. The newly-launched TESS mission will find many more of them, with the help of ground-based spectroscopic follow-up. The next generation space telescope, the James Webb Space Telescope, will hopefully characterize the atmosphere of some of them. This is an exciting time for those interested in these remote worlds."

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Under pressure, hydrogen offers a reflection of giant planet interiors

Jovian cloudscape, courtesy of NASA's Juno spacecraft.

Lab-based mimicry allowed an international team of physicists including Carnegie's Alexander Goncharov to probe hydrogen under the conditions found in the interiors of giant planets -- where experts believe it gets squeezed until it becomes a liquid metal, capable of conducting electricity. Their work is published in Science.

Hydrogen is the most-abundant element in the universe and the simplest -- comprised of only one proton and one electron in each atom. But that simplicity is deceptive, because there is still so much to learn about it, including its behavior under conditions not found on Earth.

For example, although hydrogen on the surface of giant planets, like our Solar System's Jupiter and Saturn, is a gas, just like it is on our own planet, deep inside these giant planetary interiors, scientists believe it becomes a metallic liquid.

"This transformation has been a longstanding focus of attention in physics and planetary science," said lead author Peter Celliers of Lawrence Livermore National Laboratory.

The research team -- which also included scientists from the French Alternative Energies and Atomic Energy Commission, University of Edinburgh, University of Rochester, University of California Berkeley, and George Washington University -- focused on this gas-to-metallic-liquid transition in molecular hydrogen's heavier isotope deuterium. (Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons.)

They studied how deuterium's ability to absorb or reflect light changed under up to nearly six million times normal atmospheric pressure (600 gigapascals) and at temperatures less than 1,700 degrees Celsius (about 3,140 degrees Fahrenheit). Reflectivity can indicate that a material is metallic.

They found that under about 1.5 million times normal atmospheric pressure (150 gigapascals) the deuterium switched from transparent to opaque -- absorbing the light instead of allowing it to pass through. But a transition to metal-like reflectivity started at nearly 2 million times normal atmospheric pressure (200 gigapascals).

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Astronomers identify some of the oldest galaxies in the universe

The distribution of satellite galaxies orbiting a computer-simulated galaxy, as predicted by the Lambda-cold-dark-matter cosmological model. The blue circles surround the brighter satellites, the white circles the ultrafaint satellites (so faint that they are not readily visible in the image). The ultrafaint satellites are amongst the most ancient galaxies in the Universe; they began to form when the Universe was only about 100 million years old (compared to its current age of 13.8 billion years). The image has been generated from simulations from the Auriga project carried out by researchers at the Institute for Computational Cosmology, Durham University, UK, the Heidelberg Institute for Theoretical Studies, Germany, and the Max Planck Institute for Astrophysics, Germany.

Astronomers from the Institute for Computational Cosmology at Durham University and the Harvard-Smithsonian Center for Astrophysics, have found evidence that the faintest satellite galaxies orbiting our own Milky Way galaxy are amongst the very first galaxies that formed in our Universe.

Scientists working on this research have described the finding as "hugely exciting" explaining that that finding some of the Universe's earliest galaxies orbiting the Milky Way is "equivalent to finding the remains of the first humans that inhabited the Earth."

The research group's findings suggest that galaxies including Segue-1, Bootes I, Tucana II and Ursa Major I are in fact some of the first galaxies ever formed, thought to be over 13 billion years old.

When the Universe was about 380,000 years old, the very first atoms formed. These were hydrogen atoms, the simplest element in the periodic table. These atoms collected into clouds and began to cool gradually and settle into the small clumps or "halos" of dark matter that emerged from the Big Bang.

This cooling phase, known as the "Cosmic dark ages," lasted about 100 million years. Eventually, the gas that had cooled inside the halos became unstable and began to form stars -- these objects are the very first galaxies ever to have formed.

With the formation of the first galaxies, the Universe burst into light, bringing the cosmic dark ages to an end.

Dr Sownak Bose, at Harvard-Smithsonian Center for Astrophysics, working with Dr Alis Deason and Professor Carlos Frenk at Durham University's ICC, identified two populations of satellite galaxies orbiting the Milky Way.

The first was a very faint population consisting of the galaxies that formed during the "cosmic dark ages." The second was a slightly brighter population consisting of galaxies that formed hundreds of millions of years later, once the hydrogen that had been ionized by the intense ultraviolet radiation emitted by the first stars was able to cool into more massive dark matter halos.

Remarkably, the team found that a model of galaxy formation that they had developed previously agreed perfectly with the data, allowing them to infer the formation times of the satellite galaxies.

Their findings are published in the Astrophysical Journal.

Professor Carlos Frenk, Director of Durham University's Institute for Computational Cosmology, said: "Finding some of the very first galaxies that formed in our Universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting.

"Our finding supports the current model for the evolution of our Universe, the 'Lambda-cold-dark-matter model' in which the elementary particles that make up the dark matter drive cosmic evolution."

The intense ultraviolet radiation emitted by the first galaxies destroyed the remaining hydrogen atoms by ionizing them (knocking out their electrons), making it difficult for this gas to cool and form new stars.

The process of galaxy formation ground to a halt and no new galaxies were able to form for the next billion years or so.

Eventually, the halos of dark matter became so massive that even ionized gas was able to cool. Galaxy formation resumed, culminating in the formation of spectacular bright galaxies like our own Milky Way.

Dr Sownak Bose, who was a PhD student at the ICC when this work began and is now a research fellow at the Harvard-Smithsonian Center for Astrophysics, said: "A nice aspect of this work is that it highlights the complementarity between the predictions of a theoretical model and real data.

"A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar. With the increasing sensitivity of present and future galaxy censuses, a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes."

Dr Alis Deason, who is a Royal Society University Research Fellow at the ICC, Durham University, said: "This is a wonderful example of how observations of the tiniest dwarf galaxies residing in our own Milky Way can be used to learn about the early Universe."

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Structurally 'inside-out' planetary nebula discovered

Planetary nebula HuBi 1 (left) and another planetary nebula Abell39 (right, 6800 light years away from our solar system). Abell39 is an archetypal, textbook case of a spherical nebula surrounding a bright central star (a white dwarf), its nebula composes of hydrogen-rich ionized gas. HuBi 1, its central star has undergone a "born-again" event ejecting metal-rich material into the old, hydrogen-rich nebula, has a double-shell structure - a hydrogen-rich outer shell and a nitrogen-rich inner shell.

The Instituto de Astrofísica de Andalucía (IAA-CSIC) in Spain, the Laboratory for Space Research (LSR) of the University of Hong Kong (HKU), and an International team comprising scientists from Argentina, Mexico and Germany have discovered the unusual evolution of the central star of a planetary nebula in our Milky Way. This extraordinary discovery sheds light on the future evolution, and more importantly, the ultimate fate of the Sun.

The discovery of a structurally 'inside-out' planetary nebula -- the ionized material that surrounds a white dwarf -- was just reported online in Nature Astronomy. This is also the eighth research paper produced by HKU LSR with its international collaborators in the Nature journals since 2017.

The research team believes this inverted ionization structure of the nebula is resulted from the central star undergoing a 'born-again' event, ejecting material from its surface and creating a shock that excites the nebular material.

Planetary nebulae are ionized clouds of gas formed by the hydrogen-rich envelopes of low- and intermediate-mass stars ejected at late evolutionary stages. As these stars age, they typically strip their outer layers, forming a 'wind'. As the star transitions from its red giant phase to become a white dwarf, it becomes hotter, and starts ionizing the material in the surrounding wind. This causes the gaseous material closer to the star to become highly ionized, while the gas material further out is less so.

Studying the planetary nebula HuBi 1 (17,000 light years away and nearly 5 billion years ahead of our solar system in evolution), however, Dr Martín Guerrero et al. found the reverse: HuBi 1's inner regions are less ionized, while the outer regions more so. Analysing the central star, with the participation of top theoretical astrophysicists, the authors found that it is surprisingly cool and metal-rich, and is evolved from a low-mass progenitor star which has a mass 1.1 times of the Sun.

The authors suggest that the inner nebula was excited by the passage of a shockwave caused by the star ejecting matter unusually late in its evolution. The stellar material cooled to form circumstellar dust, obscuring the star; this well explains why the central star's optical brightness has diminished rapidly over the past 50 years. In the absence of ionizing photons from the central star, the outer nebula has begun recombining -- becoming neutral. The authors conclude that, as HuBi 1 was roughly the same mass as the Sun, this finding provides a glimpse of a potential future for our solar system.

Dr Xuan Fang, co-author of the paper and a postdoctoral fellow at the HKU LSR and Department of Physics, said the extraordinary discovery resolves a long-lasting question regarding the evolutionary path of metal-rich central stars of planetary nebulae. Dr Fang has been observing the evolution of HuBi 1 early since 2014 using the Spanish flagship telescope Nordic Optical Telescope and was among the first astrophysicists to discover its inverted ionization structure.

He said: "After noting HuBi 1's inverted ionization structure and the unusual nature of its central star, we looked closer to find the reasons in collaboration with top theoretical astrophysicists in the world. We then came to realize that we had caught HuBi 1 at the exact moment when its central star underwent a brief 'born-again' process to become a hydrogen-poor [WC] and metal-rich star, which is very rare in white dwarf stars evolution."

Dr Fang, however, said the discovery would not alter the fate of the Earth. He remarked: "Our findings suggest that the Sun may also experience a 'born-again' process while it is dying out in about 5 billion years from now; but way before that event, our earth will be engulfed by the Sun when it turns into a superhot red giant and nothing living will survive."

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'Abrupt thaw' of permafrost beneath lakes could significantly affect climate change models

Methane bubbles are trapped in the ice on a pond near Fairbanks, Alaska.

Methane released by thawing permafrost from some Arctic lakes could significantly accelerate climate change, according to a new University of Alaska Fairbanks-led study.

The study, which was published Aug. 15 in the journal Nature Communications, focuses on the carbon released by thawing permafrost beneath thermokarst lakes. Such lakes develop when warming soil melts ground ice, causing the surface to collapse and form pools of water. Those pools accelerate permafrost thaw beneath the expanding lakes, providing food for microbes that produce the greenhouse gases carbon dioxide and methane.

Lead author Katey Walter Anthony and her colleagues studied hundreds of thermokarst lakes in Alaska and Siberia during a 12-year period, measuring their growth and how much methane was bubbling to their surface. By combining field work results with remote-sensing data of lake changes during the past two years, they determined the "abrupt thaw" beneath such lakes is likely to release large amounts of permafrost carbon into the atmosphere this century. The lake activity could potentially double the release from terrestrial landscapes by the 2050s.

The effort, conducted by a team of U.S. and German researchers, is part of a 10-year NASA-funded project to better understand climate change effects on the Arctic. Additional support by the National Science Foundation allowed scientists from UAF and the Alaska Division of Geological and Geophysical Surveys to collect data on permafrost location, thaw and associated greenhouse gas release from lakes in Interior Alaska's Goldstream Valley.

The researchers found the release of greenhouse gases beneath thermokarst lakes is relatively rapid, with deep thawing taking place over the course of decades. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans. The release of that surface permafrost soil carbon is often offset by an increased growth in vegetation.

"Thermokarst lakes provide a completely different scenario. When the lakes form, they flash-thaw these permafrost areas," said Walter Anthony, an associate professor with UAF's Water and Environmental Research Center. "Instead of centimeters of thaw, which is common for terrestrial environments, we've seen 15 meters of thaw beneath newly formed lakes in Goldstream Valley within the past 60 years."

Emissions from thermokarst lakes aren't currently factored into global climate models because their small size makes individual lakes difficult to include. However, the study's authors show that these lakes are hotspots of permafrost carbon release. They argue that not including them in global climate models overlooks their feedback effect, which occurs when the release of greenhouse gases from permafrost increases warming. That feedback is significant because methane is about 30 times more potent than carbon dioxide as a heat-trapping gas.

Existing models currently attribute about 20 percent of the permafrost carbon feedback this century to methane, with the rest due to carbon dioxide from terrestrial soils. By including thermokarst lakes, methane becomes the dominant driver, responsible for 70 to 80 percent of permafrost carbon-caused warming this century. Adding thermokarst methane to the models makes the feedback's effect similar to that of land-use change, which is the second-largest source of human-made warming.

Unlike shallow, gradual thawing of terrestrial permafrost, the abrupt thaw beneath thermokarst lakes is irreversible this century. Even climate models that project only moderate warming this century will have to factor in their emissions, according to the study.

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Early opaque universe linked to galaxy scarcity

Computer simulation of a region of the universe wherein a low-density "void" (dark blue region at top center) is surrounded by denser structures containing numerous galaxies (orange/white). The research done by Becker and his team suggests that early in cosmic history, these void regions would have been the murkiest places in the universe even though they contained the least amount of dark matter and gas.

A team of astronomers led by George Becker at the University of California, Riverside, has made a surprising discovery: 12.5 billion years ago, the most opaque place in the universe contained relatively little matter.

It has long been known that the universe is filled with a web-like network of dark matter and gas. This "cosmic web" accounts for most of the matter in the universe, whereas galaxies like our own Milky Way make up only a small fraction. Today, the gas between galaxies is almost totally transparent because it is kept ionized -- electrons detached from their atoms -- by an energetic bath of ultraviolet radiation.

Over a decade ago, astronomers noticed that in the very distant past -- roughly 12.5 billion years ago, or about 1 billion years after the Big Bang -- the gas in deep space was not only highly opaque to ultraviolet light, but its transparency varied widely from place to place, obscuring much of the light emitted by distant galaxies.

Then a few years ago, a team led by Becker, then at the University of Cambridge, found that these differences in opacity were so large that either the amount of gas itself, or more likely the radiation in which it is immersed, must vary substantially from place to place.

"Today, we live in a fairly homogeneous universe," said Becker, an expert on the intergalactic medium, which includes dark matter and the gas that permeates the space between galaxies. "If you look in any direction you find, on average, roughly the same number of galaxies and similar properties for the gas between galaxies, the so-called intergalactic gas. At that early time, however, the gas in deep space looked very different from one region of the universe to another."

To find out what created these differences, the team of University of California astronomers from the Riverside, Santa Barbara, and Los Angeles campuses turned to one of the largest telescopes in the world: the Subaru telescope on the summit of Mauna Kea in Hawaii. Using its powerful camera, the team looked for galaxies in a vast region, roughly 300 million light years in size, where they knew the intergalactic gas was extremely opaque.

For the cosmic web more opacity normally means more gas, and hence more galaxies. But the team found the opposite: this region contained far fewer galaxies than average. Because the gas in deep space is kept transparent by the ultraviolet light from galaxies, fewer galaxies nearby might make it murkier.

"Normally it doesn't matter how many galaxies are nearby; the ultraviolet light that keeps the gas in deep space transparent often comes from galaxies that are extremely far away. That's true for most of cosmic history, anyway," said Becker, an assistant professor in the Department of Physics and Astronomy. "At this very early time, it looks like the UV light can't travel very far, and so a patch of the universe with few galaxies in it will look much darker than one with plenty of galaxies around."

This discovery, reported in the August 2018 issue of the Astrophysical Journal, may eventually shed light on another phase in cosmic history. In the first billion years after the Big Bang, ultraviolet light from the first galaxies filled the universe and permanently transformed the gas in deep space. Astronomers believe that this occurred earlier in regions with more galaxies, meaning the large fluctuations in intergalactic radiation inferred by Becker and his team may be a relic of this patchy process, and could offer clues to how and when it occurred.

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Congenital blindness reversed in mice

An artist's rendering incorporates the images of the Müller glia-derived rod photoreceptors. These photoreceptors were structurally no different from real photoreceptors and they became integrated within the circuitry of the visual pathway, from the retina to the brain.

Researchers funded by the National Eye Institute (NEI) have reversed congenital blindness in mice by changing supportive cells in the retina called Müller glia into rod photoreceptors. The findings advance efforts toward regenerative therapies for blinding diseases such as age-related macular degeneration and retinitis pigmentosa. A report of the findings appears online today in Nature. NEI is part of the National Institutes of Health.

"This is the first report of scientists reprogramming Müller glia to become functional rod photoreceptors in the mammalian retina," said Thomas N. Greenwell, Ph.D., NEI program director for retinal neuroscience. "Rods allow us to see in low light, but they may also help preserve cone photoreceptors, which are important for color vision and high visual acuity. Cones tend to die in later-stage eye diseases. If rods can be regenerated from inside the eye, this might be a strategy for treating diseases of the eye that affect photoreceptors."

Photoreceptors are light-sensitive cells in the retina in the back of the eye that signal the brain when activated. In mammals, including mice and humans, photoreceptors fail to regenerate on their own. Like most neurons, once mature they don't divide.

Scientists have long studied the regenerative potential of Müller glia because in other species, such as zebrafish, they divide in response to injury and can turn into photoreceptors and other retinal neurons. The zebrafish can thus regain vision after severe retinal injury. In the lab, however, scientists can coax mammalian Müller glia to behave more like they do in the fish. But it requires injuring the tissue.

"From a practical standpoint, if you're trying to regenerate the retina to restore a person's vision, it is counterproductive to injure it first to activate the Müller glia," said Bo Chen, Ph.D., associate professor of ophthalmology and director of the Ocular Stem Cell Program at the Icahn School of Medicine at Mount Sinai, New York.

"We wanted to see if we could program Müller glia to become rod photoreceptors in a living mouse without having to injure its retina," said Chen, the study's lead investigator.

In the first phase of a two-stage reprogramming process Chen's team spurred Müller glia in normal mice to divide by injecting their eyes with a gene to turn on a protein called beta-catenin. Weeks later, they injected the mice's eyes with factors that encouraged the newly divided cells to develop into rod photoreceptors.

The researchers used microscopy to visually track the newly formed cells. They found that the newly formed rod photoreceptors looked structurally no different from real photoreceptors. In addition, synaptic structures that allow the rods to communicate with other types of neurons within the retina had also formed. To determine whether the Müller glia-derived rod photoreceptors were functional, they tested the treatment in mice with congenital blindness, which meant that they were born without functional rod photoreceptors.

In the treated mice that were born blind, Müller glia-derived rods developed just as effectively as they had in normal mice. Functionally, they confirmed that the newly formed rods were communicating with other types of retinal neurons across synapses. Furthermore, light responses recorded from retinal ganglion cells -- neurons that carry signals from photoreceptors to the brain -- and measurements of brain activity confirmed that the newly-formed rods were in fact integrating in the visual pathway circuitry, from the retina to the primary visual cortex in the brain.

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Next 5 years predicted to be abnormally hot

Scientists predict the next few years will be abnormally hot.

This summer's world-wide heatwave makes 2018 a particularly hot year. As will be the next few years, according to a study led by Florian Sévellec, a CNRS researcher at the Laboratory for Ocean Physics and Remote Sensing (LOPS) (CNRS/IFREMER/IRD/University of Brest) and at the University of Southampton, and published in the 14 August 2018 edition of Nature Communications. Using a new method, the study shows that at the global level, 2018-2022 may be an even hotter period than expected based on current global warming.

Warming caused by greenhouse gas emissions is not linear: it appears to have lapsed in the early 21st century, a phenomenon known as a global warming hiatus. A new method for predicting mean temperatures, however, suggests that the next few years will likely be hotter than expected.

The system, developed by researchers at CNRS, the University of Southampton and the Royal Netherlands Meteorological Institute, does not use traditional simulation techniques. Instead, it applies a statistical method to search 20th and 21st century climate simulations made using several reference models to find 'analogues' of current climate conditions and deduce future possibilities. The precision and reliability of this probabilistic system proved to be at least equivalent to current methods, particularly for the purpose of simulating the global warming hiatus of the beginning of this century.

The new method predicts that mean air temperature may be abnormally high in 2018-2022 -- higher than figures inferred from anthropogenic global warming alone. In particular, this is due to a low probability of intense cold events. The phenomenon is even more salient with respect to sea surface temperatures, due to a high probability of heat events, which, in the presence of certain conditions, can cause an increase in tropical storm activity.

Once the algorithm is 'learned' (a process which takes a few minutes), predictions are obtained in a few hundredths of a second on a laptop. In comparison, supercomputers require a week using traditional simulation methods.

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Zombie gene protects against cancer -- in elephants

African elephant, Addo Elephant National Park.

An estimated 17 percent of humans worldwide die from cancer, but less than five percent of captive elephants -- who also live for about 70 years, and have about 100 times as many potentially cancerous cells as humans -- die from the disease.

Three years ago, research teams from the University of Chicago and the University of Utah, working separately, began to unravel why. They knew that humans, like all other animals, have one copy of the master tumor suppressor gene p53. This gene enables humans and elephants to recognize unrepaired DNA damage, a precursor of cancer. Then it causes those damaged cells to die.

Unexpectedly, however, the researchers found that elephants have 20 copies of p53. This makes their cells significantly more sensitive to damaged DNA and quicker to engage in cellular suicide.

In the August 14, 2018 issue of the journal Cell Reports, the University of Chicago team describes a second element of this process: an anti-cancer gene that returned from the dead.

"Genes duplicate all the time," said Vincent Lynch, PhD, assistant professor of human genetics at the University of Chicago and the study's senior author. "Sometimes they make mistakes, producing non-functional versions known as pseudogenes. We often refer to these dismissively as dead genes."

While studying p53 in elephants, however, Lynch and colleagues found a former pseudogene called leukemia inhibitory factor 6 (LIF6) that had somehow evolved a new on-switch. LIF6, back from the dead, had become a valuable working gene. Its function, when activated by p53, is to respond to damaged DNA by killing the cell. The LIF6 gene makes a protein that goes, quite rapidly, to the mitochondria, the cell's main energy source. That protein pokes holes in the mitochondria, causing the cell to die.

"Hence, zombie," said Lynch. "This dead gene came back to life. When it gets turned on by damaged DNA, it kills that cell, quickly. This is beneficial, because it acts in response to genetic mistakes, errors made when the DNA is being repaired. Getting rid of that cell can prevent a subsequent cancer."

Elephants have eight LIF genes, but only LIF6 is known to be functional. Although it was only recently described, it appears to have been helping elephants and their relatives for a long time.

"We can use the tricks of evolution to try to figure out when this defunct gene became functional again," Lynch said. It seems to have emerged around the time when the fossil record indicates that the small groundhog-sized precursors of today's elephants began to grow bigger. This started about 25 to 30 million years ago. This supplementary method of suppressing cancer may have been a key element enabling enormous growth, which eventually led to modern elephants.

There are significant and lasting benefits to being huge. Small animals, for example -- mice, squirrels, groundhogs -- get eaten all the time, mostly by larger animals. But "if you are enormous, such as an elephant or a whale, nothing is going to mess with you," Lynch said.

There are tradeoffs, however. Bigger animals have vastly more cells, and they tend to live longer, which means more time and opportunities to accumulate cancer-causing mutations. When those cells divide, their DNA makes copies of itself. But those copies don't match the original. Errors get introduced and the repair process can't catch up.

"Large, long-lived animals must have evolved robust mechanisms to either suppress or eliminate cancerous cells in order to live as long as they do, and reach their adult sizes," said study co-author Juan Manuel Vazquez, a doctoral candidate in the Lynch laboratory.

These huge animals thus have higher odds of developing cancerous cells. This can also happen on a smaller scale. Taller humans, for example, have a slightly higher incidence of several cancer types than average sized people, and shorter people tend to be at a reduced risk for those cancers.

LIF6, the study authors suggest, was "reanimated sometime before the demands of maintaining a larger body existed." It helped enable the growth of animals that were the size of a 10-pound groundhog into majestic creatures that can weigh more than 15,000 pounds. It was "permissive for the origin of large bodies," the authors note, "but not sufficient."

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When it comes to regrowing tails, neural stem cells are the key

Salamanders tails regenerate perfectly, whereas lizard tails grow back imperfectly and mouse tails don't grow back at all.

Cut off a salamander's tail and, in a few weeks, a near-perfect replacement grows. Do the same to a lizard and a new tail will regrow, but it won't be the same as the original. By comparing tail regeneration between the two animals, researchers at the University of Pittsburgh School of Medicine found that stem cells in the spinal cord are the ultimate limiting factor.

This finding, published this week in Proceedings of the National Academy of Sciences, answers the longstanding question of why tail regeneration is perfect in the salamander and imperfect in the lizard, and may serve as a stepping stone to understanding why mice can't regenerate their tails at all.

"The traditional animal model for regeneration is the salamander," said senior author Thomas P. Lozito, Ph.D., assistant professor in Pitt's Department of Orthopaedic Surgery, Center for Cellular and Molecular Engineering and the McGowan Institute for Regenerative Medicine. "Salamanders can regenerate a wide variety of tissues -- brain, heart, parts of their eyes, limbs, tails -- but they have whole classes of molecule types and tissues that just aren't found in mammals, so we really haven't been able to apply very much of what we found in the salamander to humans."

According to Lozito, if the goal is to translate regeneration research to non-regenerating species like humans, the lizard is a much better model than the salamander. Lizards are the closest relative to mammals that can regenerate an appendage, and they have a similar genome and biochemistry. But lizards cannot regenerate lost limbs at all, and their regenerated tails are much simpler than the originals.

"You can easily tell a lizard with a regenerated tail," Lozito said. "It doesn't get anything right. The scales are different; the color pattern is different, and then when you look inside the tail, all the tissues are different. There's no bone; the skeleton is completely cartilaginous, just tubes within tubes."

Understanding what separates perfect regeneration in the salamander from imperfect regeneration in the lizard lays the groundwork for bridging the gap to non-regenerating species, Lozito said.

Lozito's lizard of choice is the mourning gecko, which has several interesting properties, including a high tolerance for transplantation.

This feature allowed his team to take neural stem cells -- the nascent precursors of neurons and glia, the non-neuronal cells that surround them -- from the salamander and insert them into the lizard's regenerating tail stump. The goal was to see what holds back tail regeneration in the lizard: the biochemical environment or the lizard's native stem cells.

They found the transplanted salamander stem cells retained their ability to differentiate into multiple cell types, including neurons. By contrast, lizard neural stem cells could become only glial cells, which don't process the messages that direct movement and feeling.

"It was a nice surprise," said lead author Aaron Sun, Ph.D., a Pitt physician-scientist trainee who completed part of his research in Lozito's lab. "And it goes to show that maybe the regenerative processes are still somewhat conserved."

But perhaps the most surprising observation, according to Sun, is that the traditionally described "neural stem cells" driving regeneration in the lizard are not "true" neural stem cells at all. Although they check many of the classic boxes, they fall short of a defining characteristic -- the ability to spring forth a diversity of cell types.

That explains why there isn't perfect tail regeneration in the lizard, Lozito said. The neural stem cells can't produce the different cell types that would be needed to recreate the asymmetries of the original spinal cord, which in turn stymies the development of bony vertebrae.

Read more at Science Daily

Scarlet macaw DNA points to ancient breeding operation in Southwest

Scarlett macaw.

Somewhere in the American Southwest or northern Mexico, there are probably the ruins of a scarlet macaw breeding operation dating to between 900 and 1200 C.E., according to a team of archaeologists who sequenced the mitochondrial DNA of bird remains found in the Chaco Canyon and Mimbres areas of New Mexico.

Remains of a thriving prehistoric avian culture and breeding colony of scarlet macaws exist at the northern Mexican site of Paquimé, or Casas Grande. However, this community existed from 1250 to 1450, well after the abandonment of Chaco Canyon, and could not have supplied these birds to Southwest communities prior to the 13th century, said Richard George, graduate student in anthropology, Penn State.

Historically, scarlet macaws lived from South America to eastern coastal Mexico and Guatemala, thousands of miles from the American Southwest. Previously, researchers thought that ancestral Puebloan people might have traveled to these natural breeding areas and brought birds back, but the logistics of transporting adolescent birds are difficult. None of the sites where these early macaw remains were found contained evidence of breeding -- eggshells, pens or perches.

"We were interested in the prehistoric scarlet macaw population history and the impacts of human direct management," said George. "Especially any evidence for directed breeding or changes in the genetic diversity that could co-occur with different trade networks."

The researchers sequenced the mitochondrial DNA of 20 scarlet macaw specimens, but were only able to obtain full sequences from 14. They then directly radiocarbon-dated all 14 birds with complete or near complete genomes and found they fell between 900 and 1200 CE.

"We looked at the full mitochondrial genome of over 16,000 base pairs to understand the maternal relationships represented in the Chaco Canyon and Mimbres regions," said George.

Mitochondrial DNA exists separate from the cell nucleus and is inherited directly from the mother. While nuclear DNA combines the DNA inherited from both parents, mitochondrial DNA can show direct lineage because all siblings have the same mtDNA as their mother, and she has the same mtDNA as her own siblings and mother, all the way back through their ancestry.

Scarlet macaws in Mexico and Central America have five haplogroups -- genetically similar, but not identical mitochondrial DNA lines -- and each haplogroup has a number of haplotypes containing identical DNA lines. The researchers found that their scarlet macaws were all from haplogroup 6 and that 71 percent of the birds shared one of four unique haplotypes. They report the results of this analysis today (Aug 13) in the Proceedings of the National Academy of Sciences.

The researchers found that the probability of obtaining 14 birds from the wild and having them all come from the same haplogroup, one that is small and isolated, was extremely small. A better explanation, especially because these specimens ranged over a 300-year period, is that all the birds came from the same breeding population and that this population existed somewhere in the American Southwest or northern Mexico.

"These birds all likely came from the same source, but we don't have any way to support that assumption without examining the full genome," said George. "However, the genetic results likely indicate some type of narrow breeding from a small founder population with little or no introgression or resupply."

However, no one has found macaw breeding evidence dating to the 900 to 1200 period in the American Southwest or northern Mexico.

Read more at Science Daily

The behavior of water: Scientists find new properties of H2O

Scuba diver looking at ice hole, while ice diving.

A team of scientists has uncovered new molecular properties of water -- a discovery of a phenomenon that had previously gone unnoticed.

Liquid water is known to be an excellent transporter of its own autoionization products; that is, the charged species obtained when a water molecule (H2O) is split into protons (H+) and hydroxide ions (OH?). This remarkable property of water makes it a critical component in emerging electrochemical energy production and storage technologies such as fuel cells; indeed, life itself would not be possible if water did not possess this characteristic.

Water is known to consist an intricate network of weak, directional interactions known as hydrogen bonds. For nearly a century, it was thought that the mechanisms by which water transports the H+ and OH? ions were mirror images of each other -- identical in all ways except for directions of the hydrogen bonds involved in the process.

Current state-of-the-art theoretical models and computer simulations, however, predicted a fundamental asymmetry in these mechanisms. If correct, this asymmetry is something that could be exploited in different applications by tailoring a system to favor one ion over the other.

Experimental proof of the theoretical prediction has remained elusive because of the difficulty in directly observing the two ionic species. Different experiments have only provided glimpses of the predicted asymmetry.

A team of scientists at New York University, led by Professor Alexej Jerschow and including Emilia Silletta, an NYU postdoctoral fellow, and Mark Tuckerman, a professor of chemistry and mathematics at NYU, devised a novel experiment for nailing down this asymmetry. The experimental approach involved cooling water down to its so-called temperature of maximum density, where the asymmetry is expected to be most strongly manifest, thereby allowing it to be carefully detected.

It is common knowledge that ice floats on water and that lakes freeze from the top. This is because water molecules pack into a structure with lower density than that of liquid water -- a manifestation of the unusual properties of water: the density of liquid water increases just above the freezing point and reaches a maximum at four degrees Celsius (39 degrees Fahrenheit), the so-called temperature of maximum density; this difference in density dictates that liquid is always situated below ice.

By cooling water down to this temperature, the team employed nuclear magnetic resonance methods (the same type of approach is medically in magnetic resonance imaging) to show that the difference in lifetimes of the two ions reaches a maximum value (the greater the lifetime, the slower the transport). By accentuating the difference in lifetimes, the asymmetry became glaringly clear.

As noted previously, water consists of one oxygen atom and two hydrogen atoms, but the hydrogen atoms are relatively mobile and can hop from one molecule to another, and it is this hopping that renders the two ionic species so mobile in water.

In seeking explanations for the temperature-dependent characteristics, the researchers focused on the speed with which such hops can occur.

Prior research had indicated that two main geometrical arrangements of hydrogen bonds (one associated with each ion) facilitate the hops. The researchers found that one of the arrangements led to significantly slower hops for OH? than for H+ at four degrees Celsius. Being that this is also the temperature of maximum density, the researchers felt that the two phenomena had to be linked. In addition, their results showed that molecules' hopping behavior changed abruptly at this temperature.

"The study of water's molecular properties is of intense interest due to its central role in enabling physiological processes and its ubiquitous nature," says Jerschow, the corresponding author of this study. "The new finding is quite surprising and may enable deeper understanding of water's properties as well as its role as a fluid in many of nature's phenomena."

Tuckerman, who was one of the first researchers to predict the asymmetry in the transport mechanisms and the difference in the hydrogen bond arrangements, says, "It is gratifying to have this clear piece of experimental evidence confirm our earlier predictions. We are currently seeking new ways to exploit the asymmetry between H+ and OH? transport to design new materials for clean energy applications, and knowing that we are starting with a correct model it central to our continued progress."

Read more at Science Daily

Unraveling the nature of 'whistlers' from space in the lab

Scientists at the University of California, Los Angeles present research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets of radio waves that race along magnetic field lines. Appearing in the Physics of Plasmas, the study provides new insights into the nature of whistlers and space plasmas and could one day aid in the development of practical plasma technologies with magnetic fields, including spacecraft thrusters that use charged particles as fuel. This image shows the growth of a whistler mode with circular phase front and cross-field propagation.

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets of radio waves that race along magnetic field lines. This first-of-its-kind study, appearing in the Physics of Plasmas, from AIP Publishing, provides new insights into the nature of whistlers and space plasmas -- regions of energized particles trapped by Earth's magnetic fields. These studies could one day aid in the development of practical plasma technologies with magnetic fields, including spacecraft thrusters that use charged particles as fuel.

"We have discovered new effects of these so-called whistler waves," said Reiner Stenzel, an author on the paper. "These new laboratory studies will help expand our knowledge on this intriguing electromagnetic phenomenon and suggest new applications and possible inventions."

Whistler waves were first detected in the early 1900s. They were found to come from lightning interacting with Earth's magnetic fields. As they traveled through Earth's ionosphere and magnetosphere, whistlers with low tones propagate more slowly than the higher frequency whistlers. As a result, simple radio receivers were used to listen to the radio waves, and the falling pitch sounded like a whistle.

Stenzel and his co-author, Manuel Urrutia, studied the growth, propagation and decay of whistler waves in nonuniform magnetic fields in their laboratory. They discovered that these waves behaved differently than predicted by an 80-year-old theory.

These laboratory studies involved creating whistler waves with magnetic antennas inside a plasma-filled chamber. The researchers then studied the behavior and propagation of these waves in 3D space with a movable probe. This enabled the team to study how these waves propagate through 3D space as a function of time. They could also study the waves under a variety of conditions, including how they behave when exposed to both straight and circular magnetic field lines and magnetic null points -- regions where there was no field at all.

"Our laboratory experiments reveal three-dimensional wave properties in ways that simply cannot be obtained from observations in space," said Stenzel. "This enabled us to study continuous waves as well as the growth and decay of waves with amazing detail. This produced unexpected discoveries of wave reflections and of cylindrical whistler modes."

Whistler waves are considered a form of helicon waves, or low-frequency electromagnetic waves that travel in a corkscrewlike, or helixlike, pattern. When helicons interact with plasmas, they exert a pressure and torque on the electrons.

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How birds learn

Zebra finch.

Children are constantly learning new things, but whether they find it easy or hard to generalise what they have learned and apply it to new situations can depend on how they learned it. It is much the same for songbirds. In their first few months of life, they too must learn a great deal; for example, the characteristic song of their species. And like people, birds also learn in different ways. How these methods impact the ability to generalise was the subject of a study on zebra finches, conducted by a research team led by Richard Hahnloser, Professor at ETH Zurich and the University of Zurich.

In their experiments, the researchers were able to show that zebra finches can learn by observing fellow members of their species. The birds had to learn through trial and error to discriminate between two classes of birdsong, one long and one short. Without any special preparation, the median number of repetitions it took for the birds to master the task was 4,700. But if the finches were able to observe other finches as they learned this task, then it took them just 900 repetitions. In this experimental set up and for statistical reasons, 800 repetitions are required in order to evaluate the animals' performance. This means that the observing birds mastered the task almost from the very beginning.

Better generalisation

In the next phase of the experiment, the researchers tested how well the zebra finches could solve a second, similar task, in which the birds had to distinguish between varying lengths of a different sample of birdsongs. This revealed that birds that learned the first task using trial and error from the outset could solve the second task practically right away: It took them a median of just 800 attempts. By contrast, birds that learned the first task primarily through observation needed a median value of 3,600 attempts.

"These results indicate that in zebra finches, learning by trial and error is the more robust method," summarises Hahnloser, continuing, "Birds that learned a perceptual skill through trial and error were better able to generalise and adapt that skill to new situations than those that learned it through observation."

Both learning methods have their advantages

Gagan Narula, a postdoc in Hahnloser's group and lead author of the study, points to parallels with how children and youths learn: "Active learning, which focuses on experimentation and trial and error, is becoming more and more prevalent in schools. In secondary schools, even maths is now being taught with the help of experiments."

Still, "both methods have their advantages," Hahnloser says, "but learning through observation is faster." He notes that the Swiss education system deliberately incorporates both learning methods: lectures and observation on the one hand, and experiments, exercises and homework on the other.

Differing degrees of brain involvement

Neural computer models assisted the scientists in interpreting their findings. From these model calculations, the researchers surmise that although the act of observation involves many synapses between neurons in a finch brain, these are relatively weak. In contrast, trial-and-error learning involves a smaller number of synapses, but they are much stronger, leading to an enhanced ability to generalise. Hahnloser explains: "When observing, the birds may focus on a large number of song details, many of which are irrelevant for solving the problem at hand. In the trial-and-error case, they remember fewer details but focus on the most prominent aspects of the song, such as its duration."

Whether different learning methods affect the brains of children and teenagers in the same way is still to be investigated. "In the past, research on zebra finches has repeatedly provided important clues and hypotheses for investigating neurobiological processes, in particular in relation to vocal learning," says Hahnloser. "Our latest findings in finches also lead to hypotheses that could be studied in humans to better understand social learning processes."

The experiment

For the experiment, the scientists used two adjacent birdcages separated by a partition, with a zebra finch in each cage. One of the finches had to use trial and error to learn to discriminate between two classes of birdsong. The other bird observed the learning process.

Each of the birds could see the other only by sitting on a particular perch in the cage next to a window in the partition. Because zebra finches are social animals, they were naturally drawn to this particular perch.

If the "experimenter" finch flew to that perch, it would hear one of ten variations of a zebra finch song. The samples had minimal differences in length, which was the defining property for splitting the song samples into two classes: Class A contained the five shorter song samples (lasting 0.9 to 1.0 seconds), and Class B had the five longer ones (1.03 to 1.13 seconds). One second after a sample from Class B was played, the team administered an air-puff to the bird.

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Amputees feel as though their prosthetic limb belongs to their own body

Amputees can learn to feel that their phantom limb actually grows into their prosthetic hand.

The famous idiom "seeing is believing" is not enough to help amputees with the use of their prosthetic limb. Many amputees opt out of prolonged use of their prosthetic limb because their missing limb simply does not fit their prosthesis. In other words, their own perception of the missing limb, or the brain's representation of it, does not match-up with what they see of the prosthesis.

The underlying problem is twofold. Amputees still feel their missing limb, even if it is physically gone, and this ghost limb aka phantom limb is perceived as much smaller that the lost limb. Next, the commercially available prosthetic limb does not yet provide sensory feedback other than what the patient sees, meaning that the patient has no sense of touch from the prosthetic limb and must constantly watch it for correct use.

Tricking the brain to embody the prosthetic limb

Now, in a scientific collaboration led by EPFL (Ecole polytechnique fédérale de Lausanne), scientists show that amputees can actually be convinced that the prosthetic hand belongs to their own body. They do this by going beyond the "seeing is believing" idiom based on established research on how the brain identifies what belongs to its own body. Instead of using the sense of sight alone, they used an astute combination of two senses: sight and touch. The results are published today in the Journal of Neurology, Neurosurgery & Psychiatry.

"The brain regularly uses its senses to evaluate what belongs to the body and what is external to the body. We showed exactly how vision and touch can be combined to trick the amputee's brain into feeling what it sees, inducing embodiment of the prosthetic hand with an additional effect that the phantom limb grows into the prosthetic one," explains Giulio Rognini of EPFL's Laboratory of Cognitive Neuroprosthetics led by Olaf Blanke, in a collaboration with Silvestro Micera of EPFL and Scuola Superiore Sant'Anna in Italy. "The setup is portable and could one day be turned into a therapy to help patients embody their prosthetic limb permanently."

In two hand amputees, the scientists provided artificial tactile sensations at the tip of the index finger -- of the phantom limb -- by stimulating the patient's nerve in the stump. At the same time, the patient wore virtual reality goggles which showed the index finger of the prosthetic limb glowing in synchrony with the administered touch sensations. This combination of virtual reality with artificial tactile sensations takes the rubber-hand illusion to another level.

Both patients reported feeling as though the prosthetic hand belonged to their own body. Moreover, when asked to evaluate the position of their hands, both patients felt as though their phantom limb had extended into the prosthetic limb. Previous to the experiment, they both reported that the phantom hand was small and directly connected to the stump, as if the phantom limb had no forearm, a change in size referred to as "telescoping" in scientific jargon. In fact, their phantom limb extended during the experiment, and remained extended for up to 10 minutes afterwards.

The experiment simply requires the patient to passively observe two sensations on the fingertip, the visual glow and the artificial touch happening in synchrony, in order for embodiment and extension of the phantom limb to take place. This is the first time that the principles of multisensory integration, in particular how the brain integrates bodily multisensory information to create the coherent and compelling experience of having a body, have been tailored to provoke embodiment of the prosthetic hand and reduction of telescoping.

Read more at Science Daily

Easter Island's society might not have collapsed

Examples of the Easter Island statues, or moai.

You probably know Easter Island as "the place with the giant stone heads." This remote island 2,300 miles off the coast of Chile has long been seen as mysterious -- a place where Polynesian seafarers set up camp, built giant statues, and then destroyed their own society through in-fighting and over-exploitation of natural resources. However, a new article in the Journal of Pacific Archaeology hints at a more complex story -- by analyzing the chemical makeup of the tools used to create the big stone sculptures, archaeologists found evidence of a sophisticated society where the people shared information and collaborated.

"For a long time, people wondered about the culture behind these very important statues," says Field Museum scientist Laure Dussubieux, one of the study's authors. "This study shows how people were interacting, it's helping to revise the theory."

"The idea of competition and collapse on Easter Island might be overstated," says lead author Dale Simpson, Jr., an archaeologist from the University of Queensland. "To me, the stone carving industry is solid evidence that there was cooperation among families and craft groups."

The first people arrived on Easter Island (or, in the local language, Rapa Nui) about 900 years ago. "The founding population, according to oral tradition, was two canoes led by the island's first chief, Hotu Matu'a," says Simpson, who is currently on the faculty of the College of DuPage. Over the years, the population rose to the thousands, forming the complex society that carved the statues Easter Island is known for today. These statues, or moai, often referred to as "Easter Island heads," are actually full-body figures that became partially buried over time. The moai, which represent important Rapa Nui ancestors, number nearly a thousand, and the largest one is over seventy feet tall.

According to Simpson, the size and number of the moai hint at a complex society. "Ancient Rapa Nui had chiefs, priests, and guilds of workers who fished, farmed, and made the moai. There was a certain level of sociopolitical organization that was needed to carve almost a thousand statues," says Simpson.

Recent excavations of four statues in the inner region of Rano Raraku, the statue quarry, were conducted by Jo Anne Van Tilburg of Cotsen Institute of Archaeology, UCLA and director of the Easter Island Statue Project, along with her Rapa Nui excavation team. To better understand the society that fabricated two of the statues, Simpson, Dussubieux, and Van Tilburg took a detailed look at twenty one of about 1,600 stone tools made of volcanic stone called basalt that had been recovered in Van Tilburg's excavations. About half of the tools, called toki, recovered were fragments that suggested how they were used.

For Van Tilburg, the goal of the project was to gain a better understanding of how tool makers and statue carvers may have interacted, thus gaining insight into how the statue production industry functioned. "We wanted to figure out where the raw materials used to manufacture the artifacts came from," explained Dussubieux. "We wanted to know if people were taking material from close to where they lived."

There are at least three different sources on Easter Island that the Rapa Nui used for material to make their stone tools. The basalt quarries cover twelve square meters, an area the size of two football fields. And those different quarries, the tools that came from them, and the movement between geological locations and archaeological sites shed light on prehistoric Rapa Nui society.

"Basalt is a grayish rock that doesn't look like anything special, but when you look at the chemical composition of the basalt samples from different sources, you can see very subtle differences in concentrations of different elements," explains Dussubieux. "Rock from each source is different because of the geology of each site."

Dussubieux led the chemical analysis of the stone tools. The archaeologists used a laser to cut off tiny pieces of stone from the toki and then used an instrument called a mass spectrometer to analyze the amounts of different chemical elements present in the samples. The results pointed to a society that Simpson believes involved a fair amount of collaboration.

"The majority of the toki came from one quarry complex -- once the people found the quarry they liked, they stayed with it," says Simpson. "For everyone to be using one type of stone, I believe they had to collaborate. That's why they were so successful -- they were working together."

To Simpson, this level of large-scale cooperation contradicts the popular narrative that Easter Island's inhabitants ran out of resources and warred themselves into extinction. "There's so much mystery around Easter Island, because it's so isolated, but on the island, people were, and still are, interacting in huge amounts," says Simpson. While the society was later decimated by colonists and slavery, Rapa Nui culture has persisted. "There are thousands of Rapa Nui people alive today -- the society isn't gone," Simpson explains.

Read more at Science Daily

Parker Solar Probe launches on historic journey to touch the sun

The United Launch Alliance Delta IV Heavy rocket is seen in this long exposure photograph as it launches NASA's Parker Solar Probe to touch the Sun, Sunday, Aug. 12, 2018 from Launch Complex 37 at Cape Canaveral Air Force Station, Florida. Parker Solar Probe is humanity’s first-ever mission into a part of the Sun’s atmosphere called the corona. Here it will directly explore solar processes that are key to understanding and forecasting space weather events that can impact life on Earth.

Hours before the rise of the very star it will study, NASA's Parker Solar Probe launched from Florida Sunday to begin its journey to the Sun, where it will undertake a landmark mission. The spacecraft will transmit its first science observations in December, beginning a revolution in our understanding of the star that makes life on Earth possible.

Roughly the size of a small car, the spacecraft lifted off at 3:31 a.m. EDT on a United Launch Alliance Delta IV Heavy rocket from Space Launch Complex-37 at Cape Canaveral Air Force Station. At 5:33 a.m., the mission operations manager reported that the spacecraft was healthy and operating normally.

The mission's findings will help researchers improve their forecasts of space weather events, which have the potential to damage satellites and harm astronauts on orbit, disrupt radio communications and, at their most severe, overwhelm power grids.

"This mission truly marks humanity's first visit to a star that will have implications not just here on Earth, but how we better understand our universe," said Thomas Zurbuchen, associate administrator of NASA's Science Mission Directorate. "We've accomplished something that decades ago, lived solely in the realm of science fiction."

During the first week of its journey, the spacecraft will deploy its high-gain antenna and magnetometer boom. It also will perform the first of a two-part deployment of its electric field antennas. Instrument testing will begin in early September and last approximately four weeks, after which Parker Solar Probe can begin science operations.

"Today's launch was the culmination of six decades of scientific study and millions of hours of effort," said project manager Andy Driesman, of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Maryland. "Now, Parker Solar Probe is operating normally and on its way to begin a seven-year mission of extreme science."

Over the next two months, Parker Solar Probe will fly towards Venus, performing its first Venus gravity assist in early October -- a maneuver a bit like a handbrake turn -- that whips the spacecraft around the planet, using Venus's gravity to trim the spacecraft's orbit tighter around the Sun. This first flyby will place Parker Solar Probe in position in early November to fly as close as 15 million miles from the Sun -- within the blazing solar atmosphere, known as the corona -- closer than anything made by humanity has ever gone before.

Throughout its seven-year mission, Parker Solar Probe will make six more Venus flybys and 24 total passes by the Sun, journeying steadily closer to the Sun until it makes its closest approach at 3.8 million miles. At this point, the probe will be moving at roughly 430,000 miles per hour, setting the record for the fastest-moving object made by humanity.

Parker Solar Probe will set its sights on the corona to solve long-standing, foundational mysteries of our Sun. What is the secret of the scorching corona, which is more than 300 times hotter than the Sun's surface, thousands of miles below? What drives the supersonic solar wind -- the constant stream of solar material that blows through the entire solar system? And finally, what accelerates solar energetic particles, which can reach speeds up to more than half the speed of light as they rocket away from the Sun?

Scientists have sought these answers for more than 60 years, but the investigation requires sending a probe right through the unrelenting heat of the corona. Today, this is finally possible with cutting-edge thermal engineering advances that can protect the mission on its daring journey.

"Exploring the Sun's corona with a spacecraft has been one of the hardest challenges for space exploration," said Nicola Fox, project scientist at APL. "We're finally going to be able to answer questions about the corona and solar wind raised by Gene Parker in 1958 -- using a spacecraft that bears his name -- and I can't wait to find out what discoveries we make. The science will be remarkable."

Parker Solar Probe carries four instrument suites designed to study magnetic fields, plasma and energetic particles, and capture images of the solar wind. The University of California, Berkeley, U.S. Naval Research Laboratory in Washington, University of Michigan in Ann Arbor, and Princeton University in New Jersey lead these investigations.

Parker Solar Probe is part of NASA's Living with a Star program to explore aspects of the Sun-Earth system that directly affect life and society. The Living with a Star program is managed by the agency's Goddard Space Flight Center in Greenbelt, Maryland, for NASA's Science Mission Directorate in Washington. APL designed and built, and operates the spacecraft.

The mission is named for Eugene Parker, the physicist who first theorized the existence of the solar wind in 1958. It's the first NASA mission to be named for a living researcher.

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Experts highlight ebola vaccine progress and suggest next steps

April 3, 2017: Study volunteer receives an inoculation at Redemption Hospital in Monrovia, Liberia on the opening day of PREVAC, a Phase 2 Ebola vaccine trial in West Africa.

Despite promising advances, important scientific questions remain unanswered in the effort to develop a safe and effective Ebola vaccine, according to members of an international Ebola research consortium. In a Viewpoint published in The Lancet, the experts review the current field of Ebola vaccine candidates and clinical trials and highlight key gaps in knowledge that need to be addressed by future research.

Researchers at the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, are among the Viewpoint's authors. All authors are with the Partnership for Research on Ebola VACcination (PREVAC). In addition to NIAID, the partnership, established in 2017, comprises experts from the French National Institute of Health and Medical Research (Inserm), the London School of Hygiene & Tropical Medicine (LSHTM), the West African Clinical Research Consortium and their collaborators. PREVAC is currently conducting a Phase 2 clinical trial in Guinea, Liberia, Sierra Leone and Mali to evaluate three Ebola vaccination strategies in people one year and older.

Ebola virus disease remains a public health threat -- the Democratic Republic of the Congo (DRC) already has experienced two Ebola outbreaks in 2018 -- underscoring the need for continued efforts to develop an effective vaccine. The authors note that 36 trials of Ebola vaccine candidates have been completed and another 14 are active, according to clinicaltrials.gov. The rVSV-ZEBOV experimental vaccine, which has been deployed in the DRC, is the only candidate with some clinical efficacy data, which were obtained in a clinical trial in Guinea conducted during the 2014-2016 Ebola outbreak in Guinea.

After reviewing the status of four additional vaccine candidates under study (Ad26.ZEBOV, MVA-BN-Filo, chAd3-EBO-Z, and the GamEvac-Combi vaccine), the authors highlight areas where more research is required. Specifically, they note the need for more data in pregnant women, children and immunocompromised populations, including people infected with HIV and the elderly. Additionally, they say more research is needed on the durability and rapidity of immune responses generated by various vaccine approaches. The experts also call for studies to identify reliable correlates of protection (the specific and measurable part of an immune response that would indicate a person is protected from Ebola) as well as large-scale trials to fully evaluate the safety and efficacy of experimental vaccines.

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Marine mammals lack functional gene to defend against popular pesticide

As marine mammals evolved to make water their primary habitat, they lost the ability to make a protein that defends humans and other land-dwelling mammals from the neurotoxic effects of a popular man-made pesticide, according to new research from the University of Pittsburgh School of Medicine.

As marine mammals evolved to make water their primary habitat, they lost the ability to make a protein that defends humans and other land-dwelling mammals from the neurotoxic effects of a popular human-made pesticide, according to new research from the University of Pittsburgh School of Medicine.

The implications of this discovery, announced today in Science, led researchers to call for monitoring our waterways to learn more about the impact of pesticides and agricultural run-off on marine mammals, such as dolphins, manatees, seals and whales. The research also may shed further light on the function of the gene encoding this protein in humans.

"We need to determine if marine mammals are, indeed, at an elevated risk of serious neurological damage from these pesticides because they biologically lack the ability to break them down, or if they've somehow adapted to avoid such damage in an as-yet undiscovered way," said senior author Nathan L. Clark, Ph.D., associate professor in Pitt's Department of Computational and Systems Biology, and the Pittsburgh Center for Evolutionary Biology and Medicine. "Either way, this is the kind of serendipitous finding that results from curiosity-driven scientific research. It is helping us to understand what our genes are doing and the impact the environment can have on them."

Clark and lead author Wynn K. Meyer, Ph.D., a postdoctoral associate in his laboratory, knew from previous research by other scientists that some genes behind smelling and tasting lost their function during the evolution of marine mammals. They set out to see what other genes conserved in land-dwelling mammals had lost function in marine mammals.

By analyzing DNA sequences from five species of marine mammals and 53 species of terrestrial mammals, the team found that Paraoxonase 1 (PON1), was the gene that best matched the pattern of losing function in marine mammals while retaining function in all terrestrial mammals. PON1 even beat out several genes responsible for smell and taste, senses that marine mammals don't rely on much.

In humans and other terrestrial mammals, PON1 reduces cellular damage caused by unstable oxygen atoms. It also protects us from organophosphates, some of which are pesticides that kill insects -- which lack PON1 -- by disrupting their neurological systems.

Clark and Meyer worked with Joseph Gaspard, Ph.D., director of science and conservation at the Pittsburgh Zoo & PPG Aquarium, and Robert K. Bonde, Ph.D., now a scientist emeritus at the U.S. Geological Survey's Wetland and Aquatic Research Center, to obtain marine mammal blood samples from U.S. and international scientists and conservation biologists. Collaborators at the University of Washington reacted blood samples from several marine mammals with an organophosphate byproduct and observed what happened. The blood did not break down the organophosphate byproduct the way it does in land mammals, indicating that, unless a different biological mechanism is protecting the marine mammals, they would be susceptible to "organophosphate poisoning," a form of poisoning that results from the buildup of chemical signals in the body, especially the brain.

In an attempt to learn why marine mammals lost PON1 function, the researchers traced back when the function was lost in three different groups of marine mammals. Whales and dolphins lost it soon after they split from their common ancestor with hippopotamuses 53 million years ago; manatees lost it after their split from their common ancestor with elephants 64 million years ago. But some seals likely lost PON1 function more recently, at most 21 million years ago and possibly in very recent times.

"The big question is, why did they lose function at PON1 in the first place?" said Meyer. "It's hard to tell whether it was no longer necessary or whether it was preventing them from adapting to a marine environment. We know that ancient marine environments didn't have organophosphate pesticides, so we think the loss might instead be related to PON1's role in responding to the extreme oxidative stress generated by long periods of diving and rapid resurfacing. If we can figure out why these species don't have functional PON1, we might learn more about the function of PON1 in human health, while also uncovering potential clues to help protect marine mammals most at risk."

As an example of the potential real-world consequences of losing function at PON1, the researchers explain in their scientific manuscript that in Florida, "agricultural use of organophosphate pesticides is common and runoff can drain into manatee habitats. In Brevard County, where 70 percent of Atlantic Coast manatees are estimated to migrate or seasonally reside, agricultural lands frequently abut manatee protection zones and waterways."

The scientists believe the next step is to launch a study that directly observes marine mammals during and shortly after periods of excess agricultural organophosphate run-off. Such a project would require increased monitoring of marine mammal habitats, as well as testing of tissues from deceased marine mammals for evidence of organophosphate exposure. The most recent estimate the research team could find of organophosphate levels in manatee habitats in Florida is a decade old, Clark said.

"Marine mammals, such as manatees or bottlenose dolphins, are sentinel species -- the canary in the coal mine," said Clark. "If you follow their health, it will tell you a lot about potential environmental issues that could eventually affect humans."

Additional authors on this research include Jerrica Jamison, Raghavendran Partha, M.Tech., Amanda Kowalczyk, B.S., Charles Kronk, B.S., and Maria Chikina, Ph.D., all of Pitt; Rebecca Richter, B.S., Judit Marsillach, Ph.D., and Clement E. Furlong, Ph.D., all of the University of Washington; Stacy E. Woods, Ph.D., M.P.H., of Johns Hopkins University; Daniel E. Crocker, Ph.D., of Sonoma State University; and Janet M. Lanyon, Ph.D., of the University of Queensland.

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