High-fidelity record of Earth's climate history puts current changes in context

 

View of Planet Earth

For the first time, climate scientists have compiled a continuous, high-fidelity record of variations in Earth's climate extending 66 million years into the past. The record reveals four distinctive climate states, which the researchers dubbed Hothouse, Warmhouse, Coolhouse, and Icehouse.

These major climate states persisted for millions and sometimes tens of millions of years, and within each one the climate shows rhythmic variations corresponding to changes in Earth's orbit around the sun. But each climate state has a distinctive response to orbital variations, which drive relatively small changes in global temperatures compared with the dramatic shifts between different climate states.

The new findings, published September 10 in Science, are the result of decades of work and a large international collaboration. The challenge was to determine past climate variations on a time scale fine enough to see the variability attributable to orbital variations (in the eccentricity of Earth's orbit around the sun and the precession and tilt of its rotational axis).

"We've known for a long time that the glacial-interglacial cycles are paced by changes in Earth's orbit, which alter the amount of solar energy reaching Earth's surface, and astronomers have been computing these orbital variations back in time," explained coauthor James Zachos, distinguished professor of Earth and planetary sciences and Ida Benson Lynn Professor of Ocean Health at UC Santa Cruz.

"As we reconstructed past climates, we could see long-term coarse changes quite well. We also knew there should be finer-scale rhythmic variability due to orbital variations, but for a long time it was considered impossible to recover that signal," Zachos said. "Now that we have succeeded in capturing the natural climate variability, we can see that the projected anthropogenic warming will be much greater than that."

For the past 3 million years, Earth's climate has been in an Icehouse state characterized by alternating glacial and interglacial periods. Modern humans evolved during this time, but greenhouse gas emissions and other human activities are now driving the planet toward the Warmhouse and Hothouse climate states not seen since the Eocene epoch, which ended about 34 million years ago. During the early Eocene, there were no polar ice caps, and average global temperatures were 9 to 14 degrees Celsius higher than today.

"The IPCC projections for 2300 in the 'business-as-usual' scenario will potentially bring global temperature to a level the planet has not seen in 50 million years," Zachos said.

Critical to compiling the new climate record was getting high-quality sediment cores from deep ocean basins through the international Ocean Drilling Program (ODP, later the Integrated Ocean Drilling Program, IODP, succeeded in 2013 by the International Ocean Discovery Program). Signatures of past climates are recorded in the shells of microscopic plankton (called foraminifera) preserved in the seafloor sediments. After analyzing the sediment cores, researchers then had to develop an "astrochronology" by matching the climate variations recorded in sediment layers with variations in Earth's orbit (known as Milankovitch cycles).

"The community figured out how to extend this strategy to older time intervals in the mid-1990s," said Zachos, who led a study published in 2001 in Science that showed the climate response to orbital variations for a 5-million-year period covering the transition from the Oligocene epoch to the Miocene, about 25 million years ago.

"That changed everything, because if we could do that, we knew we could go all the way back to maybe 66 million years ago and put these transient events and major transitions in Earth's climate in the context of orbital-scale variations," he said.

Zachos has collaborated for years with lead author Thomas Westerhold at the University of Bremen Center for Marine Environmental Sciences (MARUM) in Germany, which houses a vast repository of sediment cores. The Bremen lab along with Zachos's group at UCSC generated much of the new data for the older part of the record.

Westerhold oversaw a critical step, splicing together overlapping segments of the climate record obtained from sediment cores from different parts of the world. "It's a tedious process to assemble this long megasplice of climate records, and we also wanted to replicate the records with separate sediment cores to verify the signals, so this was a big effort of the international community working together," Zachos said.

Now that they have compiled a continuous, astronomically dated climate record of the past 66 million years, the researchers can see that the climate's response to orbital variations depends on factors such as greenhouse gas levels and the extent of polar ice sheets.

"In an extreme greenhouse world with no ice, there won't be any feedbacks involving the ice sheets, and that changes the dynamics of the climate," Zachos explained.

Most of the major climate transitions in the past 66 million years have been associated with changes in greenhouse gas levels. Zachos has done extensive research on the Paleocene-Eocene Thermal Maximum (PETM), for example, showing that this episode of rapid global warming, which drove the climate into a Hothouse state, was associated with a massive release of carbon into the atmosphere. Similarly, in the late Eocene, as atmospheric carbon dioxide levels were dropping, ice sheets began to form in Antarctica and the climate transitioned to a Coolhouse state.

"The climate can become unstable when it's nearing one of these transitions, and we see more deterministic responses to orbital forcing, so that's something we would like to better understand," Zachos said.

The new climate record provides a valuable framework for many areas of research, he added. It is not only useful for testing climate models, but also for geophysicists studying different aspects of Earth dynamics and paleontologists studying how changing environments drive the evolution of species.

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New Hubble data suggests there is an ingredient missing from current dark matter theories

 

This Hubble Space Telescope image shows the massive galaxy cluster MACSJ 1206. Embedded within the cluster are the distorted images of distant background galaxies, seen as arcs and smeared features. These distortions are caused by the dark matter in the cluster, whose gravity bends and magnifies the light from faraway galaxies, an effect called gravitational lensing. This phenomenon allows astronomers to study remote galaxies that would otherwise be too faint to see. Astronomers measured the amount of gravitational lensing caused by this cluster to produce a detailed map of the distribution of dark matter in it. Dark matter is the invisible glue that keeps stars bound together inside a galaxy and makes up the bulk of the matter in the Universe. The Hubble image is a combination of visible- and infrared-light observations taken in 2011 by the Advanced Camera for Surveys and Wide Field Camera 3.

Observations by the NASA/ESA Hubble Space Telescope and the European Southern Observatory's Very Large Telescope (VLT) in Chile have found that something may be missing from the theories of how dark matter behaves. This missing ingredient may explain why researchers have uncovered an unexpected discrepancy between observations of the dark matter concentrations in a sample of massive galaxy clusters and theoretical computer simulations of how dark matter should be distributed in clusters. The new findings indicate that some small-scale concentrations of dark matter produce lensing effects that are 10 times stronger than expected.

Dark matter is the invisible glue that keeps stars, dust, and gas together in a galaxy. This mysterious substance makes up the bulk of a galaxy's mass and forms the foundation of our Universe's large-scale structure. Because dark matter does not emit, absorb, or reflect light, its presence is only known through its gravitational pull on visible matter in space. Astronomers and physicists are still trying to pin down what it is.

Galaxy clusters, the most massive and recently assembled structures in the Universe, are also the largest repositories of dark matter. Clusters are composed of individual member galaxies that are held together largely by the gravity of dark matter.

"Galaxy clusters are ideal laboratories in which to study whether the numerical simulations of the Universe that are currently available reproduce well what we can infer from gravitational lensing," said Massimo Meneghetti of the INAF-Observatory of Astrophysics and Space Science of Bologna in Italy, the study's lead author.

"We have done a lot of testing of the data in this study, and we are sure that this mismatch indicates that some physical ingredient is missing either from the simulations or from our understanding of the nature of dark matter," added Meneghetti.

"There's a feature of the real Universe that we are simply not capturing in our current theoretical models," added Priyamvada Natarajan of Yale University in Connecticut, USA, one of the senior theorists on the team. "This could signal a gap in our current understanding of the nature of dark matter and its properties, as these exquisite data have permitted us to probe the detailed distribution of dark matter on the smallest scales."

The distribution of dark matter in clusters is mapped by measuring the bending of light -- the gravitational lensing effect -- that they produce. The gravity of dark matter concentrated in clusters magnifies and warps light from distant background objects. This effect produces distortions in the shapes of background galaxies which appear in images of the clusters. Gravitational lensing can often also produce multiple images of the same distant galaxy.

The higher the concentration of dark matter in a cluster, the more dramatic its light-bending effect. The presence of smaller-scale clumps of dark matter associated with individual cluster galaxies enhances the level of distortions. In some sense, the galaxy cluster acts as a large-scale lens that has many smaller lenses embedded within it.

Hubble's crisp images were taken by the telescope's Wide Field Camera 3 and Advanced Camera for Surveys. Coupled with spectra from the European Southern Observatory's Very Large Telescope (VLT), the team produced an accurate, high-fidelity, dark-matter map. By measuring the lensing distortions astronomers could trace out the amount and distribution of dark matter. The three key galaxy clusters, MACS J1206.2-0847, MACS J0416.1-2403, and Abell S1063, were part of two Hubble surveys: The Frontier Fields and the Cluster Lensing And Supernova survey with Hubble (CLASH) programs.

To the team's surprise, in addition to the dramatic arcs and elongated features of distant galaxies produced by each cluster's gravitational lensing, the Hubble images also revealed an unexpected number of smaller-scale arcs and distorted images nested near each cluster's core, where the most massive galaxies reside. The researchers believe the nested lenses are produced by the gravity of dense concentrations of matter inside the individual cluster galaxies. Follow-up spectroscopic observations measured the velocity of the stars orbiting inside several of the cluster galaxies to therby pin down their masses.

"The data from Hubble and the VLT provided excellent synergy," shared team member Piero Rosati of the Università degli Studi di Ferrara in Italy, who led the spectroscopic campaign. "We were able to associate the galaxies with each cluster and estimate their distances."

"The speed of the stars gave us an estimate of each individual galaxy's mass, including the amount of dark matter," added team member Pietro Bergamini of the INAF-Observatory of Astrophysics and Space Science in Bologna, Italy.

By combining Hubble imaging and VLT spectroscopy, the astronomers were able to identify dozens of multiply imaged, lensed, background galaxies. This allowed them to assemble a well-calibrated, high-resolution map of the mass distribution of dark matter in each cluster.

The team compared the dark-matter maps with samples of simulated galaxy clusters with similar masses, located at roughly the same distances. The clusters in the computer model did not show any of the same level of dark-matter concentration on the smallest scales -- the scales associated with individual cluster galaxies.

"The results of these analyses further demonstrate how observations and numerical simulations go hand in hand," said team member Elena Rasia of the INAF-Astronomical Observatory of Trieste, Italy.

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Giant particle accelerator in the sky

 The Earth's magnetic field is trapping high energy particles. When the first satellites were launched into space, scientists led by James Van Allen unexpectedly discovered the high energy particle radiation regions, which were later named after its discoverer Van Allen Radiation Belts. Visualized, these look like two donut-shaped regions encompassing our planet.

Now, a new study led by researchers from GFZ German Research Centre for Geosciences shows that electrons in the radiation belts can be accelerated to very high speeds locally. The study shows that magnetosphere works as a very efficient particle accelerator speeding up electrons to so-called ultra-relativistic energies. The study conducted by Hayley Allison, a postdoctoral scholar at GFZ Potsdam, and Yuri Shprits from GFZ and Professor at the University of Potsdam, is published in Nature Communications.

To better understand the origin of the Van Allen Belts, in 2012 NASA launched the Van Allen Probes twin spacecraft to traverse this most harsh environment and conduct detailed measurements in this hazardous region. The measurements included a full range of particles moving at different speeds and in different directions and plasma waves. Plasma waves are similar to the waves that we see on the water surface, but are in fact invisible to the naked eye. They can be compared to ripples in the electric and magnetic field.

Recent observations revealed that the energy of electrons in the belts can go up to so called ultra-relativistic energies. These electrons with temperatures above 100 Billion degrees Fahrenheit, move so fast that their energy of motion is much higher than their energy of rest given by Einstein's famous E=mc2 formula. They are so fast that the time flow significantly slows down for these particles.

Scientists were surprised to find these ultra-relativistic electrons and assumed that such high energies can be only reached by a combination of two processes: the inward transport of particles from the outer regions of the magnetosphere, which accelerates them; and a local acceleration of particles by plasma waves.

However, the new study shows that electrons reach such incredible energies locally, in the heart of the belts, by taking all this energy from plasma waves. This process turns out to be extremely efficient. The unexpected discovery of how acceleration of particles to ultra-relativistic energies operates in the near-Earth space, may help scientists understand the fundamental processes of acceleration on the Sun, near outer planets, and even in the distant corners of the universe where space probes cannot reach.

From Science Daily

Unique supernova explosion

 One-hundred million light years away from Earth, an unusual supernova is exploding.

That exploding star -- which is known as "supernova LSQ14fmg" -- was the faraway object discovered by a 37-member international research team led by Florida State University Assistant Professor of Physics Eric Hsiao. Their research, which was published in the Astrophysical Journal, helped uncover the origins of the group of supernovae this star belongs to.

This supernova's characteristics -- it gets brighter extremely slowly, and it is also one of the brightest explosions in its class -- are unlike any other.

"This was a truly unique and strange event, and our explanation for it is equally interesting," said Hsiao, the paper's lead author.

The exploding star is what is known as a Type Ia supernova, and more specifically, a member of the "super-Chandrasekhar" group.

Stars go through a sort of life cycle, and these supernovae are the exploding finale of some stars with low mass. They are so powerful that they shape the evolution of galaxies, and so bright that we can observe them from Earth even halfway across the observable universe.

An image of the "Blue Snowball" planetary nebula taken with the Florida State University Observatory. The supernova LSQ14fmg exploded in a system similar to this, with a central star losing a copious amount of mass through a stellar wind. When the mass loss abruptly stopped, it created a ring of material surrounding the star. Courtesy of Eric Hsiao

Type Ia supernovae were crucial tools for discovering what's known as dark energy, which is the name given to the unknown energy that causes the current accelerated expansion of the universe. Despite their importance, astronomers knew little about the origins of these supernova explosions, other than that they are the thermonuclear explosions of white dwarf stars.

But the research team knew that the light from a Type Ia supernova rises and falls over the course of weeks, powered by the radioactive decay of nickel produced in the explosion. A supernova of that type would get brighter as the nickel becomes more exposed, then fainter as the supernova cools and the nickel decays to cobalt and to iron.

After collecting data with telescopes in Chile and Spain, the research team saw that the supernova was hitting some material surrounding it, which caused more light to be released along with the light from the decaying nickel. They also saw evidence that carbon monoxide was being produced. Those observations led to their conclusion -- the supernova was exploding inside what had been an asymptotic giant branch (AGB) star on the way to becoming a planetary nebula.

"Seeing how the observation of this interesting event agrees with the theory is very exciting," said Jing Lu, an FSU doctoral candidate and a co-author of the paper.

They theorized that the explosion was triggered by the merger of the core of the AGB star and another white dwarf star orbiting within it. The central star was losing a copious amount of mass through a stellar wind before the mass loss was turned off abruptly and created a ring of material surrounding the star. Soon after the supernova exploded, it impacted a ring of material often seen in planetary nebulae and produced the extra light and the slow brightening observed.

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Loss of a pet can potentially trigger mental health issues in children

 The death of a family pet can trigger a sense of grief in children that is profound and prolonged, and can potentially lead to subsequent mental health issues, according to a new study by researchers at Massachusetts General Hospital (MGH). In a paper appearing in European Child & Adolescent Psychiatry, the team found that the strong emotional attachment of youngsters to pets might result in measurable psychological distress that can serve as an indicator of depression in children and adolescents for as long as three years or more after the loss of a beloved pet.

"One of the first major losses a child will encounter is likely to be the death of a pet, and the impact can be traumatic, especially when that pet feels like a member of the family," says Katherine Crawford, CGC, previously with the Center for Genomic Medicine at MGH, and lead author of the study. "We found this experience of pet death is often associated with elevated mental health symptoms in children, and that parents and physicians need to recognize and take those symptoms seriously, not simply brush them off."

Roughly half of households in developed countries own at least one pet. And as the MGH investigators reported, the bonds that children form with pets can resemble secure human relationships in terms of providing affection, protection and reassurance. What's more, previous studies have shown that children often turn to pets for comfort and to voice their fears and emotional experiences. While the increased empathy, self-esteem and social competence that often flow from this interaction is clearly beneficial, the downside is the exposure of children to the death of a pet which, the MGH study found, occurs with 63 percent of children with pets during their first seven years of life.

Prior research has focused on the attachment of adults to pets and the consequences of an animal's death. The MGH team is the first to examine mental health responses in children. Their analysis is based on a sample of 6,260 children from the Avon Longitudinal Study of Parents and Children (ALSPAC), in Bristol, England. This population-based sample is replete with data collected from mothers and children that enabled researchers to track the experience of pet ownership and pet loss from a child's early age up to eight years.

"Thanks to this cohort, we were able to analyze the mental and emotional health of children after examining their experiences with pet death over an extended period," notes Erin Dunn, ScD, MPH, with the MGH Center for Genomic Medicine and Department of Psychiatry, and senior author of the study. "And we observed that the association between exposure to a pet's death and psychopathology symptoms in childhood occurred regardless of the child's socio-economic status or hardships they had already endured in their young lives."

Researchers also learned that the relationship between pet death and increased psychopathology was more pronounced in male than female children -- a finding that surprised them in light of prior research -- and that the strength of the association was independent of when the pet's death occurred during childhood, and how many times or how recently it occurred. According to Dunn, this latter finding speaks to "the durability of the bond with pets that is formed at a very early age, and how it can affect children across their development."

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COVID-19 study links strict social distancing to much lower chance of infection

 

People social distancing concept

Using public transportation, visiting a place of worship, or otherwise traveling from the home is associated with a significantly higher likelihood of testing positive with the coronavirus SARS-CoV-2, while practicing strict social distancing is associated with a markedly lower likelihood, suggests a study from researchers at the Johns Hopkins Bloomberg School of Public Health.

For their analysis, the researchers surveyed a random sample of more than 1,000 people in the state of Maryland in late June, asking about their social distancing practices, use of public transportation, SARS-CoV-2 infection history, and other COVID-19-relevant behaviors. They found, for example, that those reporting frequent public transport use were more than four times as likely to report a history of testing positive for SARS-CoV-2 infection, while those who reported practicing strict outdoor social distancing were just a tenth as likely to report ever being SARS-CoV-2 positive.

The study is believed to be among the first large-scale evaluations of COVID-19-relevant behaviors that is based on individual-level survey data, as opposed to aggregated data from sources such as cellphone apps.

The results were published online on September 2 in Clinical Infectious Diseases.

"Our findings support the idea that if you're going out, you should practice social distancing to the extent possible because it does seem strongly associated with a lower chance of getting infected," says study senior author Sunil Solomon, MBBS, PhD, MPH, an associate professor in the Bloomberg School's Department of Epidemiology and an associate professor of medicine at Johns Hopkins School Medicine. "Studies like this are also relatively easy to do, so we think they have the potential to be useful tools for identification of places or population subgroups with higher vulnerability."

The novel coronavirus SARS-CoV-2 has infected nearly 27 million people around the world, of whom some 900,000 have died, according to the World Health Organization. In the absence of a vaccine, public health authorities have emphasized practices such as staying at home, and wearing masks and maintaining social distancing while in public. Yet there hasn't been a good way to monitor whether -- and among which groups -- such practices are being followed.

Solomon and colleagues, including first author Steven Clipman, a PhD candidate in the Bloomberg School's Department of International Health, quickly accessed willing survey participants via a company that maintains a large nationwide pool of potential participants as a commercial service for market research. The 1,030 people included in the study were all living in Maryland, which has logged more than 113,000 SARS-CoV-2 confirmed cases and nearly 3,700 confirmed deaths, according to the Maryland Department of Health.

The researchers asked the survey participants questions about recent travel outside the home, their use of masks, social distancing and related practices, and any confirmed infection with SARS-CoV-2 either recently or at all.

The results indicated that 55 (5.3 percent) of the 1,030 participants had tested positive for SARS-CoV-2 infection at any time, while 18 (1.7 percent) reported testing positive in the two weeks before they were surveyed.

The researchers found that when considering all the variables they could evaluate, spending more time in public places was strongly associated with having a history of SARS-CoV-2 infection. For example, an infection history was about 4.3 times more common among participants who stated that they had used public transportation more than three times in the prior two weeks, compared to participants who stated they had never used public transportation in the two-week period.

An infection history also was 16 times more common among those who reported having visited a place of worship three or more times in the prior two weeks, compared to those who reported visiting no place of worship during the period. The survey did not distinguish between visiting a place of worship for a religious service or other purposes, such as a meeting, summer camp or meal.

Conversely, those who reported practicing social distancing outdoors "always" were only 10 percent as likely to have a SARS-CoV-2 history, compared to those who reported "never" practicing social distancing.

An initial, relatively simple analysis linked many other variables to SARS-CoV-2 infection history, including being Black or Hispanic. But a more sophisticated, "multivariable" analysis suggested that many of these apparent links were largely due to differences in movement and social distancing.

"When we adjusted for other variables such as social distancing practices, a lot of those simple associations went away, which provides evidence that social distancing is an effective measure for reducing SARS-CoV-2 transmission," Clipman says.

The data indicated a greater adoption of social distancing practices among some groups who are especially vulnerable to serious COVID-19 illness, suggesting that they were relatively aware of their vulnerability. For example, 81 percent of over-65 participants reported always practicing social distancing at outdoor activities, while only 58 percent of 18-24 year olds did so.

The results are consistent with the general public health message that mask-wearing, social distancing, and limiting travel whenever possible reduce SARS-CoV-2 transmission. The researchers suggest, though, that studies such as these, employing similarly rapid surveys of targeted groups, could also become useful tools for predicting where and among which groups infectious diseases will spread most quickly.

"We did this study in Maryland in June, and it showed among other things that younger people in the state were less likely to reduce their infection risk with social distancing -- and a month later a large proportion of the SARS-CoV-2 infections detected in Maryland was among younger people," says Solomon. "So, it points to the possibility of using these quick, inexpensive surveys to predict where outbreaks are going to happen based on behaviors, and then mobilizing public health resources accordingly."

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Atomistic modelling probes the behavior of matter at the center of Jupiter

 The hydrogen atom, with its single proton orbited by a single electron, is arguably the simplest material out there. Elemental hydrogen can nonetheless exhibit extremely complex behavior -- at megabar pressures, for example, it undergoes a transition from being an insulating fluid to being a metallic conductive fluid.

While the transition is fascinating simply from the point of view of condensed matter physics and materials science -- liquid-liquid phase transitions are rather unusual -- it also has significant implications for planetary science, since liquid hydrogen makes up the interior of giant planets such as Jupiter and Saturn as well as brown dwarf stars. Understanding the liquid-liquid transition is then a central part of accurately modelling the structure and evolution of such planets and standard models generally assume a sharp transition between the insulating molecular fluid and the conducting metallic fluid. This sharp transition is linked to a discontinuity in density and therefore a clear border between an inner metallic mantle and an outer insulating mantle in these planets.

While scientists have made considerable efforts to explore and characterize this transition as well as dense hydrogen's many unusual properties -- including rich and poorly understood solid polymorphism, anomalous melting line, and the possible transition to a superconducting state -- laboratory investigation is complicated because of the need to create a controllable high pressure and temperature environment as well as to confine hydrogen during measurements. Experimental research has then not yet reached a consensus on whether the transition is abrupt or smooth and different experiments have located the liquid-liquid transition at pressures that are as much as 100 gigapascals apart.

"The kind of experiment that you need to be able to do to be able to study a material in the same range of pressures that you find on Jupiter is highly non-trivial," Ceriotti said. "As a result of the constraints, many different experiments have been performed, with results that are very different from each other."

Though modelling techniques introduced in the last decade have allowed scientists to better understand the system, the huge computational expense involved in essentially solving the quantum mechanical problem for the behavior of hydrogen atoms has meant that these simulations were necessarily limited in time, to a scale of a few picoseconds, and to a scope of just a few hundred atoms. Results here have also been mixed.

In order to examine the problem more thoroughly, Ceriotti and colleagues Bingqing Chen at the University of Cambridge and Guglielmo Mazzola at IBM Research Zurich used an artificial neural network architecture to construct a machine learning potential. Based on a small number of very accurate (and time consuming) calculations of the electronic structure problem, the inexpensive machine-learning potential allowed for the investigation of hydrogen phase transitions for temperatures between 100 and 4000 K, and pressures between 25 and 400 gigapascals, with converged simulation size and time. The simulations, mostly run on EPFL computers at SCITAS, took just a few weeks compared with the 100s of millions of years in CPU time that it would have taken to run traditional simulations for solving the quantum mechanical problem.

The resulting theoretical study of the phase diagram of dense hydrogen allowed the team to reproduce the re-entrant melting behavior and the polymorphism of the solid phase. Simulations based on the machine learning potential showed, contrary to the common assumption that hydrogen undergoes a first-order phase transition, evidence of continuous metallization in the liquid. This in turn not only suggests a smooth transition between insulating and metallic layers in giant gas planets, it also reconciles existing discrepancies between both lab and modelling experiments.

"If high-pressure hydrogen is supercritical, as our simulations suggest, there is no sharp transition where all the properties of the fluid have a sudden jump," Ceriotti said. "Depending on the exact property you probe, and the way you define a threshold, you would find the transition to occur at a different temperature or pressure. This may reconcile a decade of controversial results from high pressure experiments. Different experiments have measured slightly different things and they haven't been able to identify the transition at the same point because there is no sharp transition."

In terms of reconciling their results with some earlier modelling that indeed identified a sharp transition, Ceriotti says that they could only observe a clear-cut jump in properties when performing small simulations, and that in those cases they could trace the jump to solidification, rather than to a liquid-liquid transition. The sharp transition observed should then rather be understood as an artifact of the limitations of using simulations based on traditional physics-based modelling. The machine learning approach has allowed the researchers to run simulations that are typically between 4 and 10 times larger and several 100s of times longer. This gives them a much better overview of the entire process.

While it was applied in this particular paper to an issue linked to planetary science, the same technology can be applied to any problem in materials science or chemistry, Ceriotti said.

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Tool transforms world landmark photos into 4D experiences

 Using publicly available tourist photos of world landmarks such as the Trevi Fountain in Rome or Top of the Rock in New York City, Cornell University researchers have developed a method to create maneuverable 3D images that show changes in appearance over time.

The method, which employs deep learning to ingest and synthesize tens of thousands of mostly untagged and undated photos, solves a problem that has eluded experts in computer vision for six decades.

"It's a new way of modeling scenes that not only allows you to move your head and see, say, the fountain from different viewpoints, but also gives you controls for changing the time," said Noah Snavely, associate professor of computer science at Cornell Tech and senior author of "Crowdsampling the Plenoptic Function," presented at the European Conference on Computer Vision, held virtually Aug. 23-28.

"If you really went to the Trevi Fountain on your vacation, the way it would look would depend on what time you went -- at night, it would be lit up by floodlights from the bottom. In the afternoon, it would be sunlit, unless you went on a cloudy day," Snavely said. "We learned the whole range of appearances, based on time of day and weather, from these unorganized photo collections, such that you can explore the whole range and simultaneously move around the scene."

Representing a place in a photorealistic way is challenging for traditional computer vision, partly because of the sheer number of textures to be reproduced. "The real world is so diverse in its appearance and has different kinds of materials -- shiny things, water, thin structures," Snavely said.

Another problem is the inconsistency of the available data. Describing how something looks from every possible viewpoint in space and time -- known as the plenoptic function -- would be a manageable task with hundreds of webcams affixed around a scene, recording data day and night. But since this isn't practical, the researchers had to develop a way to compensate.

"There may not be a photo taken at 4 p.m. from this exact viewpoint in the data set. So we have to learn from a photo taken at 9 p.m. at one location, and a photo taken at 4:03 from another location," Snavely said. "And we don't know the granularity of when these photos were taken. But using deep learning allows us to infer what the scene would have looked like at any given time and place."

The researchers introduced a new scene representation called Deep Multiplane Images to interpolate appearance in four dimensions -- 3D, plus changes over time. Their method is inspired in part on a classic animation technique developed by the Walt Disney Company in the 1930s, which uses layers of transparencies to create a 3D effect without redrawing every aspect of a scene.

"We use the same idea invented for creating 3D effects in 2D animation to create 3D effects in real-world scenes, to create this deep multilayer image by fitting it to all these disparate measurements from the tourists' photos," Snavely said. "It's interesting that it kind of stems from this very old, classic technique used in animation."

In the study, they showed that this model could be trained to create a scene using around 50,000 publicly available images found on sites such as Flickr and Instagram. The method has implications for computer vision research, as well as virtual tourism -- particularly useful at a time when few can travel in person.

"You can get the sense of really being there," Snavely said. "It works surprisingly well for a range of scenes."

First author of the paper is Cornell Tech doctoral student Zhengqi Li. Abe Davis, assistant professor of computer science in the Faculty of Computing and Information Science, and Cornell Tech doctoral student Wenqi Xian also contributed.

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People who were children when their parents divorced have less 'love hormone'

 People who were children when their parents were divorced showed lower levels of oxytocin -- the so-called "love hormone" -- when they were adults than those whose parents remained married, according to a study led by Baylor University. That lower level may play a role in having trouble forming attachments when they are grown.

Oxytocin -- secreted in the brain and released during bonding experiences such as delivery of a baby or sexual interaction or nursing, even being hugged by a romantic partner -- has been shown in previous research to be important for social behavior and emotional attachments in early life. The oxytocin system also has been linked to parenting, attachment and anxiety.

The new study, published in the Journal of Comparative Psychology, delves into an area that has not been well researched -- a link between oxytocin, early experience and adult outcomes.

"Since the rates of divorce in our society began to increase, there has been concern about the effects of divorce on the children," said lead author Maria Boccia, Ph.D., professor of child and family studies at Baylor University in the Robbins College of Health and Human Sciences. "Most research has focused on short-term effects, like academic performance, or longer-term outcomes like the impact on relationships. How divorce causes these effects, however, is unknown.

"Oxytocin is a neurohormone that is important in regulating these behaviors and is also sensitive to the impact of stressful life events in early life," she said. "This is a first step towards understanding what mechanisms might be involved."

Previous studies of children whose parents were divorced have found that the experience was associated with mood disorders and substance abuse -- behaviors found to be related to oxytocin, Boccia said. Additionally, such childhood experiences as divorce or death of a parent are associated with depression and anxiety in adolescents and adults, as well as with poorer parenting in adulthood, less parental sensitivity and warmth, overreaction and increased use of punishment.

Researchers in the Baylor study examined the effect of the experience of parental divorce in childhood on later adult oxytocin levels. They also asked participants to complete a set of questionnaires on attachment style and other measures.

"What we found was that oxytocin was substantially lower in people who experienced parental divorce compared to those who did not and correlated with responses on several measures of attachment," Boccia said. "These results suggest that oxytocin levels are adversely affected by parental divorce and may be related to other effects that have been documented in people who experience parental divorce."

Animal studies also suggest that one mechanism contributing to the negative effects of early parental separation may be suppression of oxytocin activity.

For the latest study, researchers recruited 128 individuals ages 18 to 62 at two institutions of higher learning in the Southeast United States. Of those, 27.3% indicated their parents were divorced. The average age for participants when their parents divorced was 9 years.

Upon arriving at the study site, participants were asked to empty their bladders, then given a 16-ounce bottle of water to drink before filling out questionnaires about their parents and peers during childhood, as well as their current social functioning. The questions addressed their parents' style, including affection, protection, indifference, over-control and abuse; and their own levels of confidence, discomfort with closeness, need for approval and their styles of relationships and caregiving.

After participants completed the questionnaires, urine samples were collected, and researchers analyzed oxytocin concentrations. The levels were substantially lower in individuals whose childhood experience included their parents' divorce.

Further analysis showed that those individuals rated their parents as less caring and more indifferent. They also rated their fathers as more abusive. Those who experienced parental divorce during childhood were less confident, more uncomfortable with closeness and less secure in relationships. They rated their own caregiving style as less sensitive and close than did the participants whose parents had not divorced.

"One of the first questions I am asked when presenting this research to other scientists is 'does how old the child is when the divorce occurs matter?' That is the most pressing question that we need to explore," Boccia said.

Read more at Science Daily

Unconscious learning underlies belief in God, study suggests

 

Hands raised to sunset, prayer concept

Individuals who can unconsciously predict complex patterns, an ability called implicit pattern learning, are likely to hold stronger beliefs that there is a god who creates patterns of events in the universe, according to neuroscientists at Georgetown University.

Their research, reported in the journal Nature Communications, is the first to use implicit pattern learning to investigate religious belief. The study spanned two very different cultural and religious groups, one in the U.S. and one in Afghanistan.

The goal was to test whether implicit pattern learning is a basis of belief and, if so, whether that connection holds across different faiths and cultures. The researchers indeed found that implicit pattern learning appears to offer a key to understanding a variety of religions.

"Belief in a god or gods who intervene in the world to create order is a core element of global religions," says the study's senior investigator, Adam Green, an associate professor in the Department of Psychology and Interdisciplinary Program in Neuroscience at Georgetown, and director of the Georgetown Laboratory for Relational Cognition.

"This is not a study about whether God exists, this is a study about why and how brains come to believe in gods. Our hypothesis is that people whose brains are good at subconsciously discerning patterns in their environment may ascribe those patterns to the hand of a higher power," he adds.

"A really interesting observation was what happened between childhood and adulthood," explains Green. The data suggest that if children are unconsciously picking up on patterns in the environment, their belief is more likely to increase as they grow up, even if they are in a nonreligious household. Likewise, if they are not unconsciously picking up on patterns around them, their belief is more likely to decrease as they grow up, even in a religious household.

The study used a well-established cognitive test to measure implicit pattern learning. Participants watched as a sequence of dots appeared and disappeared on a computer screen. They pressed a button for each dot. The dots moved quickly, but some participants -- the ones with the strongest implicit learning ability -- began to subconsciously learn patterns hidden in the sequence, and even press the correct button for the next dot before that dot actually appeared. However, even the best implicit learners did not know that the dots formed patterns, showing that the learning was happening at an unconscious level.

The U.S. section of the study enrolled a predominantly Christian group of 199 participants from Washington, D.C. The Afghanistan section of the study enrolled a group of 149 Muslim participants in Kabul. The study's lead author was Adam Weinberger, a postdoctoral researcher in Green's lab at Georgetown and at the University of Pennsylvania. Co-authors Zachery Warren and Fathali Moghaddam led a team of local Afghan researchers who collected data in Kabul.

"The most interesting aspect of this study, for me, and also for the Afghan research team, was seeing patterns in cognitive processes and beliefs replicated across these two cultures," says Warren. "Afghans and Americans may be more alike than different, at least in certain cognitive processes involved in religious belief and making meaning of the world around us. Irrespective of one's faith, the findings suggest exciting insights into the nature of belief."

"A brain that is more predisposed to implicit pattern learning may be more inclined to believe in a god no matter where in the world that brain happens to find itself, or in which religious context," Green adds, though he cautions that further research is necessary.

"Optimistically," Green concludes, "this evidence might provide some neuro-cognitive common ground at a basic human level between believers of disparate faiths."

Read more at Science Daily

The oldest Neanderthal DNA of Central-Eastern Europe

 Around 100,000 years ago, the climate worsened abruptly and the environment of Central-Eastern Europe shifted from forested to open steppe/taiga habitat, promoting the dispersal of wooly mammoth, wooly rhino and other cold adapted species from the Arctic. Neanderthals living in these territories suffered severe demographic contractions due to the new ecological conditions and only returned to the areas above 48° N latitude during climatic ameliorations. However, in spite of the discontinuous settlement, specific bifacial stone tools persisted in Central-Eastern Europe from the beginning of this ecological shift until the demise of the Neanderthals. This cultural tradition is named Micoquian, and spread across the frosty environment between eastern France, Poland and the Caucasus. Previous genetic analyses showed that two major demographic turnover events in Neanderthal history are associated with the Micoquian cultural tradition. At ~90,000 years ago, western European Neanderthals replaced the local Altai Neanderthals population in Central Asia. Successively, by at least ~45,000 years ago, western European Neanderthals substituted the local groups in the Caucasus.

The paper published in Scientific Reports and led by researchers of the Max Planck Institute for Evolutionary Anthropology in Germany, Wroclaw University, Institute of Systematics and Evolution of Animals Polish Academy of Sciences, and University of Bologna reports the oldest mitochondrial genome of a Neanderthal found in Central-Eastern Europe. The molecular age of ~80,000 years places the tooth from Stajnia Cave in this important period of Neanderthal history when the environment was characterized by extreme seasonality and some groups dispersed eastwards to Central Asia. "Poland, located at the crossroad between the Western European Plains and the Urals, is a key region in understanding these migrations and for solving questions about the adaptability and biology of Neanderthals in periglacial habitat. The Stajnia S5000 molar is truly an exceptional find that sheds light on the debate over the wide distribution of the Micoquian artefacts," says Andrea Picin, lead author of the study and Postdoctoral Researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig.

Genetic analysis

Neanderthal remains associated with the Micoquian cultural tradition are very few and genetic information has only been extracted from samples of Germany, Northern Caucasus and Altai. "We were aware of the geographical importance of this tooth for adding more chronological points in the distribution map of genetic information of Neanderthals," says Mateja Hajdinjak, co-author of the paper and Postdoctoral Researcher at the Max Planck Institute for Evolutionary Anthropology. "We found that the mitochondrial genome of Stajnia S5000 was closest to the one of a Mezmaiskaya 1 Neanderthal from the Caucasus. We then used the molecular genetic clock in order to determine its approximate age. Although the molecular branch shortening approach comes with a wide error range, crossing the information with the archaeological record permitted us to place the fossil at the beginning of the Last Glacial."

The tooth was discovered in 2007 during fieldwork directed by Mikolaj Urbanowski, co-author of the paper, within animal bones and a few stone tools. The opening of the cave was probably too narrow for prolonged settlement, and Neanderthal occupations were short-term. The site could have been a logistical location settled during forays into the Krakow-Czestochowa Upland.

"We were thrilled when the genetic analysis revealed that the tooth was at least ~80,000 years old. Fossils of this age are very difficult to find and, generally, the DNA is not well preserved," say Wioletta Nowaczewska of Wroclaw University and Adam Nadachowski from the Institute of Systematics and Evolution of Animals Polish Academy of Sciences, co-authors of the paper. "At the beginning, we thought that the tooth was younger since it was found in an upper layer. We were aware that Stajnia Cave is a complex site, and post-depositional frost disturbance mixed artefacts between layers. We are happily surprised by the result." Concerning the paleoanthropological features, Stefano Benazzi of Bologna University, co-author of the paper, adds, "The morphology of the tooth is typical of Neanderthal, which was also confirmed by the genetic analysis. The worn condition of the crown suggests that it belonged to an adult."

Neanderthals in periglacial environments

Archaeologists have been puzzled for a long time by the resilience of Neanderthals in these regions and by the persistence of Micoquian stone tools for more than 50,000 years across a huge area. Beyond the taphonomic issues, the lithic assemblage of Stajnia displays a set of features that are common to several key sites in Germany, Crimea, Northern Caucasus and Altai. These similarities are likely the result of increasing mobility of Neanderthal groups that frequently moved across the Northern and Eastern European Plains chasing cold adapted migratory animals. The Prut and Dniester rivers were probably used as the main corridors of dispersal from Central Europe to the Caucasus. Similar corridors could also have been used at ~45,000 years ago when other western Neanderthals carrying Micoquian stone tools replaced local populations at Mezmaiskaya Cave in the Caucasus.

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Ancient hunters stayed in frozen Northern Europe rather than migrating to warmer areas, evidence from Arctic fox bones shows

 Ancient hunters stayed in the coldest part of Northern Europe rather than migrating to escape freezing winter conditions, archaeologists have found.

Evidence from Arctic fox bones show communities living around 27,500 years ago were killing small prey in the inhospitable North European Plains during the winter months of the last Ice Age.

Researchers have found no evidence of dwellings, suggesting people only stayed for a short time or lived in tents in the area excavated, Kraków Spadzista in Southern Poland -- one of the largest Upper Palaeolithic sites in Central Europe. Until now it wasn't clear if people retreated elsewhere each winter to avoid the intense cold.

Dr Alexander Pryor, from the University of Exeter, who led the study, said: "Our research shows the cold harsh winter climates of the last ice age were no barrier to human activity in the area. Hunters made very specific choices about where and when to kill their prey."

Inhabitants of Kraków Spadzista around 27,500 years ago killed and butchered large numbers of woolly mammoths and arctic foxes at the site. For the first time, the research team were able to reconstruct details of how the foxes were moving around in the landscape before they died, and also what time of the year they died, through analysing the internal chemistry and growth structures of their tooth enamel and roots.

The analysis of teeth from four of the 29 hunted foxes show each was born and grew up in a different location, and had migrated either tens or hundreds of kilometres to the region before being killed by hunters -- by snares, deadfalls or other trapping methods -- for both their thick warm furs as well as meat and fat for food. The carcasses were brought back to the site to be skinned and butchered.

Analysis of the dental cementum of at least 10 fox individuals demonstrate that the majority were killed between late winter and late spring, most likely in late winter. The foxes ranged in age, from sub-adult to very old.

The study, published in the Journal of Archaeological Science: Reports, also involved Sylwia Pospuła, Piotr Wojtal, Nina Kowalik and Jarosław Wilczyński from the Polish Academy of Sciences and Tereza Nesnídalová from the University of Exeter.

Around 2,400 arctic fox bones were found about 30m south of a huge concentration of bones from more than 100 individual woolly mammoths that dominate the site, in an area used for the production of lithic tools and the processing of smaller prey animals.

The study suggests the Arctic fox colonised the area because they moved over long distances season by season, something they still do today, in order to find food.

Dr Pryor said: "Arctic fox provided both food and hides to Palaeolithic hunters, with their fur coats reaching full length around the beginning of December; this winter fur usually begins shedding by early spring. They also lay down substantial stores of body fats seasonally that are greatest from late autumn throughout the winter season and do not start to become seriously depleted until early spring. Hunters most likely targeted the foxes in the late winter period -- before the onset of fur shedding and loss of critical fat supplies.

"The high numbers of fox remains found at the site suggests what was happening was a deliberate, organised procurement strategy rather than just simple incidental hunting."

The analysis of teeth suggests hunters engaged in large-scale winter hunting of solitary Arctic foxes that were ranging widely across the landscape. The site was used as a base camp for ranging visits to maintain trapping lines and for processing hides.

Read more at Science Daily

Lost frogs rediscovered with environmental DNA

 Scientists have detected signs of a frog listed extinct and not seen since 1968, using an innovative technique to locate declining and missing species in two regions of Brazil.

The frog, Megaelosia bocainensis, was among seven total species -- including four other declining species, and two that had disappeared locally for many years -- that were detected. The findings appeared in a paper, "Lost and Found: Frogs in a Biodiversity Hotspot Rediscovered with Environmental DNA," published in August in Molecular Ecology.

Megaelosia bocainensis. A disappeared species from Parque Nacional da Serra da Bocaina, Brazil, known only from this museum specimen collected in 1968, and detected by eDNA surveys. In the study, the researchers collected and screened environmental DNA (eDNA) in the biodiverse Atlantic Coastal Forest and Cerrado grasslands of Brazil.

The eDNA technique offers a way to survey that can confirm the presence of species undetected by traditional methods, providing a tool for conservation scientists to evaluate the presence of threatened species, especially those with low population densities and those not seen in years.

After careful research to identify species at various levels of threat in these regions of Brazil, the researchers used the eDNA method to search for 30 target amphibian species in six localities where the frogs were known to previously live.

"Little bits of DNA in the environment don't tell us about how many individuals there are or whether those individuals are healthy, but it does tell us that the species is still present," said senior author Kelly Zamudio, the Goldwin Smith Professor of Ecology and Evolutionary Biology in the College of Arts and Sciences.

"This is one more kind of survey data, and for species that are declining or locally disappeared, it not only means they are there, but there's now the potential to study them in more detail," she said, noting that for many species, very little is known.

Around the world, conservationists have been challenged to keep pace with declining and disappearing amphibians. At the same time, living organisms leave DNA traces in the soil, water and air. Now, scientists are increasingly using highly sensitive sampling techniques to detect eDNA for conservation purposes.

In the study, the researchers targeted 13 frog species that have totally disappeared and are presumed extinct; 12 frogs that have disappeared locally but are still found in other parts of their range; and five species that were once very abundant and are still there but hard to find.

The researchers hiked into the sampling sites carrying battery packs, a shoebox-sized peristaltic pump and backpacks of sterile tubing. They used the pump and tubing to draw up to 60 liters of stream or pond water through a capsule fitted with a filter for capturing DNA. A buffer was then applied to stabilize and preserve the DNA on the filter.

Back in the lab, the researchers extracted the DNA, genetically sequenced it, weeded out genetic material from humans, pigs, chickens and other organisms until they could isolate all the frog DNA.

"Now you've got a subset of genetic sequences that we know only belong to frogs, and then it's step by step, going finer and finer, until you get to the genus and species you are looking for," Zamudio said.

Identifying M. bocainensis required clever detective work: The species disappeared long ago, and there were no tissues from which to extract DNA for comparison with the eDNA. But the researchers did have the sequences for all the sister species in the genus Megaelosia and they knew the ranges of the sister species and M. bocainensis.

"We know there's a Megaelosia there," Zamudio said, "we just don't know which one it is, but the only one that has ever been reported there historically is the one that went missing. Do we believe it? That's how far the analysis can take us."

Read more at Science Daily

How to have a blast like a black hole

 Laser Engineering at Osaka University have successfully used short, but extremely powerful laser blasts to generate magnetic field reconnection inside a plasma. This work may lead to a more complete theory of X-ray emission from astronomical objects like black holes.

In addition to being subjected to extreme gravitational forces, matter being devoured by a black hole can be also be pummeled by intense heat and magnetic fields. Plasmas, a fourth state of matter hotter than solids, liquids, or gasses, are made of electrically charged protons and electrons that have too much energy to form neutral atoms. Instead, they bounce frantically in response to magnetic fields. Within a plasma, magnetic reconnection is a process in which twisted magnetic field lines suddenly "snap" and cancel each other, resulting in the rapid conversion of magnetic energy into particle kinetic energy. In stars, including our sun, reconnection is responsible for much of the coronal activity, such as solar flares. Owing to the strong acceleration, the charged particles in the black hole's accretion disk emit their own light, usually in the X-ray region of the spectrum.

To better understand the process that gives rise to the observed X-rays coming from black holes, scientists at Osaka University used intense laser pulses to create similarly extreme conditions on the lab. "We were able to study the high-energy acceleration of electrons and protons as the result of relativistic magnetic reconnection," Senior author Shinsuke Fujioka says. "For example, the origin of emission from the famous black hole Cygnus X-1, can be better understood."

This level of light intensity is not easily obtained, however. For a brief instant, the laser required two petawatts of power, equivalent to one thousand times the electric consumption of the entire globe. With the LFEX laser, the team was able to achieve peak magnetic fields with a mind-boggling 2,000 telsas. For comparison, the magnetic fields generated by an MRI machine to produce diagnostic images are typically around 3 teslas, and Earth's magnetic field is a paltry 0.00005 teslas. The particles of the plasma become accelerated to such an extreme degree that relativistic effects needed to be considered.

"Previously, relativistic magnetic reconnection could only be studied via numerical simulation on a supercomputer. Now, it is an experimental reality in a laboratory with powerful lasers," first author King Fai Farley Law says. The researchers believe that this project will help elucidate the astrophysical processes that can happen at places in the Universe that contain extreme magnetic fields.

From Science Daily

Children use both brain hemispheres to understand language, unlike adults

 Infants and young children have brains with a superpower, of sorts, say Georgetown University Medical Center neuroscientists. Whereas adults process most discrete neural tasks in specific areas in one or the other of their brain's two hemispheres, youngsters use both the right and left hemispheres to do the same task. The finding suggests a possible reason why children appear to recover from neural injury much easier than adults.

The study published Sept. 7, 2020 in PNAS focuses on one task, language, and finds that to understand language (more specifically, processing spoken sentences), children use both hemispheres. This finding fits with previous and ongoing research, led by Georgetown neurology professor Elissa L. Newport, PhD, a former postdoctoral fellow Olumide Olulade, MD, PhD, and neurology assistant professor Anna Greenwald, PhD.

"This is very good news for young children who experience a neural injury," says Newport, director of the Center for Brain Plasticity and Recovery, a joint enterprise of Georgetown University and MedStar National Rehabilitation Network. "Use of both hemispheres provides a mechanism to compensate after a neural injury. For example, if the left hemisphere is damaged from a perinatal stroke -- one that occurs right after birth -- a child will learn language using the right hemisphere. A child born with cerebral palsy that damages only one hemisphere can develop needed cognitive abilities in the other hemisphere. Our study demonstrates how that is possible."

Their study solves a mystery that has puzzled clinicians and neuroscientists for a long time, says Newport.

In almost all adults, sentence processing is possible only in the left hemisphere, according to both brain scanning research and clinical findings of language loss in patients who suffered a left hemisphere stroke.

But in very young children, damage to either hemisphere is unlikely to result in language deficits; language can be recovered in many patients even if the left hemisphere is severely damaged. These facts suggest that language is distributed to both hemispheres early in life, Newport says. However, traditional scanning had not revealed the details of these phenomena until now. "It was unclear whether strong left dominance for language is present at birth or appears gradually during development," explains Newport.

Now, using functional magnetic resonance imaging (fMRI) analyzed in a more complex way, the researchers have shown that the adult lateralization pattern is not established in young children and that both hemispheres participate in language during early development.

Brain networks that localize specific tasks to one or the other hemisphere start during childhood but are not complete until a child is about 10 or 11, she says. "We now have a better platform upon which to understand brain injury and recovery."

The study, originally run by collaborators William D. Gaillard, MD, and Madison M. Berl, PhD, of Children's National Medical Center, enrolled 39 healthy children, ages 4-13; Newport's lab added 14 adults, ages 18-29, and conducted a series of new analyses of both groups. The participants were given a well-studied sentence comprehension task. The analyses examined fMRI activation patterns in each hemisphere of the individual participants, rather than looking at overall lateralization in group averages. Investigators then compared the language activation maps for four age groups: 4-6, 7-9, 10-13, and 18-29. Penetrance maps revealed the percentage of subjects in each age group with significant language activation in each voxel of each hemisphere. (A voxel is a tiny point in the brain image, like a pixel on a television monitor.) Investigators also performed a whole-brain analysis across all participants to identify brain areas in which language activation was correlated with age.

Researchers found that, at the group level, even young children show left-lateralized language activation. However, a large proportion of the youngest children also show significant activation in the corresponding right-hemisphere areas. (In adults, the corresponding area in the right hemisphere is activated in quite different tasks, for example, processing emotions expressed with the voice. In young children, areas in both hemispheres are each engaged in comprehending the meaning of sentences as well as recognizing the emotional affect.)

Newport believes that the "higher levels of right hemisphere activation in a sentence processing task and the slow decline in this activation over development are reflections of changes in the neural distribution of language functions and not merely developmental changes in sentence comprehension strategies."

She also says that, if the team were able to do the same analysis in even younger children, "it is likely we would see even greater functional involvement of the right hemisphere in language processing than we see in our youngest participants (ages 4-6 years old).

"Our findings suggest that the normal involvement of the right hemisphere in language processing during very early childhood may permit the maintenance and enhancement of right hemisphere development if the left hemisphere is injured," Newport says.

Read more at Science Daily

Researchers track nutrient transport in the Gulf of Mexico

 Researchers from Florida State University are shedding light on nutrient levels in the Gulf of Mexico with new findings published this month in the Journal of Geophysical Research -- Oceans.

The Gulf of Mexico receives considerable levels of nutrients from the rivers that empty into it, especially the Mississippi River, which causes the Gulf's northern shelf waters to become overly enriched and more susceptible to algae growth. But scientists have remained unsure whether a significant portion of those nutrients ever leave the Gulf to potentially impact the chemistry of the North Atlantic Ocean.

"The Gulf of Mexico is an economically important body of water, as the surrounding areas rely on it for tourism, fisheries and oil production, and it also has significant ecological diversity," said Samantha Howe, a graduate student in the College of Arts and Sciences' Department of Earth, Ocean and Atmospheric Science, who led the research. "It is important to track the nutrient input from the Mississippi and Atchafalaya River System to the Gulf as those nutrients contribute to harmful algal blooms on the Northern Gulf Shelf."

Researchers found no evidence that nitrate from the Mississippi-Atchafalaya River System is mixing across the Northern Gulf shelf into the open waters of the Gulf of Mexico. The findings are consistent with recent modeling work by fellow scientists that indicates 90 percent of Mississippi River nutrients are retained in the near-shore ecosystem, which implies that nutrients from the Mississippi River do not leave the Gulf.

"In order to assess and manage ecological challenges in the Gulf, it is critical to understand whether the nutrients are processed and retained nearshore or whether they are transported to the North Atlantic," Howe said. "This finding is valuable to know, as these ecosystems must harbor the nutrient burden."

To conduct the study, the team collected and analyzed water samples taken during four different research cruises to the Gulf and the Florida Straits from 2011 to 2018.

The research is the first ever to provide isotopic composition measurements of nitrate in the Gulf of Mexico, as well as a new isotopic profile from the Florida Straits. These new water column profiles were then compared with prior measurements from the North and South Atlantic and with the magnitude of nitrogen inputs to the Gulf.

Howe, who earned her bachelor's degree in environmental science from FSU in Spring 2019, is now pursuing her master's in aquatic environmental science. She began the nutrient research as part of her honors undergraduate thesis while working in the research lab of study co-author, Associate Professor of Oceanography Angela Knapp.

"Samantha's thesis looked for distinct geochemical signatures of nitrate from the Mississippi River and whether this nitrate made it off the Northern Gulf of Mexico shelf into the deep waters of the Gulf that mix with the Loop Current and leave via the Florida Straits to enter the North Atlantic," Knapp said.

Howe's collaborators on the study include co-authors Knapp and Carlos Miranda, a 2017 graduate of the FSU Department of Chemistry and Biochemistry and the FSU Department of Biological Science, and colleagues from the University of Southern Mississippi and the University of New Hampshire.

 Read more at Science Daily

Meteorite study suggests Earth may have been wet since it formed

 

Planet Earth

A new study finds that Earth's water may have come from materials that were present in the inner solar system at the time the planet formed -- instead of far-reaching comets or asteroids delivering such water. The findings published Aug. 28 in Science suggest that Earth may have always been wet.

Researchers from the Centre de Recherches Petrographiques et Geochimiques (CRPG, CNRS/Universite de Lorraine) in Nancy, France, including one who is now a postdoctoral fellow at Washington University in St. Louis, determined that a type of meteorite called an enstatite chondrite contains sufficient hydrogen to deliver at least three times the amount of water contained in the Earth's oceans, and probably much more.

Enstatite chondrites are entirely composed of material from the inner solar system -- essentially the same stuff that made up the Earth originally.

"Our discovery shows that the Earth's building blocks might have significantly contributed to the Earth's water," said lead author Laurette Piani, a researcher at CPRG. "Hydrogen-bearing material was present in the inner solar system at the time of the rocky planet formation, even though the temperatures were too high for water to condense."

The findings from this study are surprising because the Earth's building blocks are often presumed to be dry. They come from inner zones of the solar system where temperatures would have been too high for water to condense and come together with other solids during planet formation.

The meteorites provide a clue that water didn't have to come from far away.

"The most interesting part of the discovery for me is that enstatite chondrites, which were believed to be almost 'dry,' contain an unexpectedly high abundance of water," said Lionel Vacher, a postdoctoral researcher in physics in Arts & Sciences at Washington University in St. Louis.

Vacher prepared some of the enstatite chondrites in this study for water analysis while he was completing his PhD at Universite de Lorraine. At Washington University, Vacher is working on understanding the composition of water in other types of meteorites.

Enstatite chondrites are rare, making up only about 2 percent of known meteorites in collections.

But their isotopic similarity to Earth make them particularly compelling. Enstatite chondrites have similar oxygen, titanium and calcium isotopes as Earth, and this study showed that their hydrogen and nitrogen isotopes are similar to Earth's, too. In the study of extraterrestrial materials, the abundances of an element's isotopes are used as a distinctive signature to identify where that element originated.

"If enstatite chondrites were effectively the building blocks of our planet -- as strongly suggested by their similar isotopic compositions -- this result implies that these types of chondrites supplied enough water to Earth to explain the origin of Earth's water, which is amazing!" Vacher said.

The paper also proposes that a large amount of the atmospheric nitrogen -- the most abundant component of the Earth's atmosphere -- could have come from the enstatite chondrites.

"Only a few pristine enstatite chondrites exist: ones that were not altered on their asteroid nor on Earth," Piani said. "In our study we have carefully selected the enstatite chondrite meteorites and applied a special analytical procedure to avoid being biased by the input of terrestrial water."

Coupling two analytical techniques -- conventional mass spectrometry and secondary ion mass spectrometry (SIMS) -- allowed researchers to precisely measure the content and composition of the small amounts of water in the meteorites.

Read more at Science Daily

Ancient bony fish forces rethink of how sharks evolved

 Sharks' non-bony skeletons were thought to be the template before bony internal skeletons evolved, but a new fossil discovery suggests otherwise.

The discovery of a 410-million-year-old fish fossil with a bony skull suggests the lighter skeletons of sharks may have evolved from bony ancestors, rather than the other way around.

Sharks have skeletons made cartilage, which is around half the density of bone. Cartilaginous skeletons are known to evolve before bony ones, but it was thought that sharks split from other animals on the evolutionary tree before this happened; keeping their cartilaginous skeletons while other fish, and eventually us, went on to evolve bone.

Now, an international team led by Imperial College London, the Natural History Museum and researchers in Mongolia have discovered a fish fossil with a bony skull that is an ancient cousin of both sharks and animals with bony skeletons. This could suggest the ancestors of sharks first evolved bone and then lost it again, rather than keeping their initial cartilaginous state for more than 400 million years.

The team published their findings today in Nature Ecology & Evolution.

Lead researcher Dr Martin Brazeau, from the Department of Life Sciences at Imperial, said: "It was a very unexpected discovery. Conventional wisdom says that a bony inner skeleton was a unique innovation of the lineage that split from the ancestor of sharks more than 400 million years ago, but here is clear evidence of bony inner skeleton in a cousin of both sharks and, ultimately, us."

Most of the early fossils of fish have been uncovered in Europe, Australia and the USA, but in recent years new finds have been made in China and South America. The team decided to dig in Mongolia, where there are rocks of the right age that have not been searched before.

They uncovered the partial skull, including the brain case, of a 410-million-year-old fish. It is a new species, which they named Minjinia turgenensis, and belongs to a broad group of fish called 'placoderms', out of which sharks and all other 'jawed vertebrates' -- animals with backbones and mobile jaws -- evolved.

When we are developing as foetuses, humans and bony vertebrates have skeletons made of cartilage, like sharks, but a key stage in our development is when this is replaced by 'endochondral' bone -- the hard bone that makes up our skeleton after birth.

Previously, no placoderm had been found with endochondral bone, but the skull fragments of M. turgenensis were "wall-to-wall endochondral." While the team are cautious not to over-interpret from a single sample, they do have plenty of other material collected from Mongolia to sort through and perhaps find similar early bony fish.

And if further evidence supports an early evolution of endochondral bone, it could point to a more interesting history for the evolution of sharks.

Dr Brazeau said: "If sharks had bony skeletons and lost it, it could be an evolutionary adaptation. Sharks don't have swim bladders, which evolved later in bony fish, but a lighter skeleton would have helped them be more mobile in the water and swim at different depths.

Read more at Science Daily

'Wild West' mentality lingers in modern populations of US mountain regions

 When historian Frederick Jackson Turner presented his famous thesis on the US frontier in 1893, he described the "coarseness and strength combined with acuteness and acquisitiveness" it had forged in the American character.

Now, well into the 21st century, researchers led by the University of Cambridge have detected remnants of the pioneer personality in US populations of once inhospitable mountainous territory, particularly in the Midwest.

A team of scientists algorithmically investigated how landscape shapes psychology. They analysed links between the anonymised results of an online personality test completed by over 3.3 million Americans, and the "topography" of 37,227 US postal -- or ZIP -- codes.

The researchers found that living at both a higher altitude and an elevation relative to the surrounding region -- indicating "hilliness" -- is associated with a distinct blend of personality traits that fits with "frontier settlement theory."

"The harsh and remote environment of mountainous frontier regions historically attracted nonconformist settlers strongly motivated by a sense of freedom," said researcher Friedrich Götz, from Cambridge's Department of Psychology.

"Such rugged terrain likely favoured those who closely guarded their resources and distrusted strangers, as well as those who engaged in risky explorations to secure food and territory."

"These traits may have distilled over time into an individualism characterised by toughness and self-reliance that lies at the heart of the American frontier ethos" said Götz, lead author of the study.

"When we look at personality across the whole United States, we find that mountainous residents are more likely to have psychological characteristics indicative of this frontier mentality."

Götz worked with colleagues from the Karl Landsteiner University of Health Sciences, Austria, the University of Texas, US, the University of Melbourne in Australia, and his Cambridge supervisor Dr Jason Rentfrow. The findings are published in the journal Nature Human Behaviour.

The research uses the "Big Five" personality model, standard in social psychology, with simple online tests providing high-to-low scores for five fundamental personality traits of millions of Americans.

The mix of characteristics uncovered by study's authors consists of low levels of "agreeableness," suggesting mountainous residents are less trusting and forgiving -- traits that benefit "territorial, self-focused survival strategies."

Low levels of "extraversion" reflect the introverted self-reliance required to thrive in secluded areas, and a low level of "conscientiousness" lends itself to rebelliousness and indifference to rules, say researchers.

"Neuroticism" is also lower, suggesting an emotional stability and assertiveness suited to frontier living. However, "openness to experience" is much higher, and the most pronounced personality trait in mountain dwellers.

"Openness is a strong predictor of residential mobility," said Götz. "A willingness to move your life in pursuit of goals such as economic affluence and personal freedom drove many original North American frontier settlers."

"Taken together, this psychological fingerprint for mountainous areas may be an echo of the personality types that sought new lives in unknown territories."

The researchers wanted to distinguish between the direct effects of physical environment and the "sociocultural influence" of growing up where frontier values and identities still hold sway.

To do this, they looked at whether mountainous personality patterns applied to people born and raised in these regions that had since moved away.

The findings suggest some "initial enculturation" say researchers, as those who left their early mountain home are still consistently less agreeable, conscientious and extravert, although no such effects were observed for neuroticism and openness.

The scientists also divided the country at the edge of St. Louis -- "gateway to the West" -- to see if there is a personality difference between those in mountains that made up the historic frontier, such as the Rockies, and eastern ranges e.g. the Appalachians.

While mountains continue to be a "meaningful predictor" of personality type on both sides of this divide, key differences emerged. Those in the east are more agreeable and outgoing, while western ranges are a closer fit for frontier settlement theory.

In fact, the mountainous effect on high levels of "openness to experience" is ten times as strong in residents of the old western frontier as in those of the eastern ranges.

The findings suggest that, while ecological effects are important, it is the lingering sociocultural effects -- the stories, attitudes and education -- in the former "Wild West" that are most powerful in shaping mountainous personality, according to scientists.

They describe the effect of mountain areas on personality as "small but robust," but argue that complex psychological phenomena are influenced by many hundreds of factors, so small effects are to be expected.

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Bering Sea ice extent is at most reduced state in last 5,500 years

 Through the analysis of vegetation from a Bering Sea island, researchers have determined that the extent of sea ice in the region is lower than it's been for thousands of years.

A newly published paper in the journal Science Advances describes how a peat core from St. Matthew Island is providing a look back in time. By analyzing the chemical composition of the core, which includes plant remains from 5,500 years ago to the present, scientists can estimate how sea ice in the region has changed during that time period.

"It's a small island in the middle of the Bering Sea, and it's essentially been recording what's happening in the ocean and atmosphere around it," said lead author Miriam Jones, a research geologist with the U.S. Geological Survey. Jones worked as a faculty researcher at the University of Alaska Fairbanks when the project began in 2012.

The ancient sea ice record comes in the form of changes in the relative amounts of two isotopes of the element oxygen -- oxygen-16 and oxygen-18. The ratio of those two isotopes changes depending on patterns in the atmosphere and ocean, reflecting the different signatures that precipitation has around the globe. More oxygen-18 makes for an isotopically "heavier" precipitation, more oxygen-16 makes precipitation "lighter."

By analyzing data from a model that tracks atmospheric movement using the isotopic signature of precipitation, the authors found that heavier precipitation originated from the North Pacific, while lighter precipitation originated from the Arctic.

A "heavy" ratio signals a seasonal pattern that causes the amount of sea ice to decrease. A "light" ratio indicates a season with more sea ice. That connection has been confirmed though sea ice satellite data collected since 1979, and to a smaller extent, through the presence of some microorganisms in previous core samples.

UAF's Alaska Stable Isotope Facility analyzed isotope ratios throughout the peat layers, providing a time stamp for ice conditions that existed through the millennia.

After reviewing the isotopic history, researchers determined that modern ice conditions are at remarkably low levels.

"What we've seen most recently is unprecedented in the last 5,500 years," said Matthew Wooller, director of the Alaska Stable Isotope Facility and a contributor to the paper. "We haven't seen anything like this in terms of sea ice in the Bering Sea."

Jones said the long-term findings also affirm that reductions in Bering Sea ice are due to more than recent higher temperatures associated with global warming. Atmospheric and ocean currents, which are also affected by climate change, play a larger role in the presence of sea ice.

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A 400-year-old chamois will serve as a model for research on ice mummies

 At first glance, the chamois carcass did not seem to Hermann Oberlechner to be an unusual discovery as mountaineers often happen across the remains of wild animals during their high-altitude excursions. However, upon a close inspection of the chamois skin, the Ahrntal alpinist realised that he was faced with a highly unique discovery and informed the relevant ranger.

The chamois had in fact been protected by the glacier for 400 years and only recently released due to the ice having receded. With the help of the Alpine Army Corps, the chamois mummy was brought back to the valley and entrusted to Eurac Research for scientific study by the Department of Cultural Heritage. Due to their age and state of preservation, the remains are in fact a perfect simulant of a human mummy and will allow researchers to improve the conservation techniques of ice mummies all over the world while determining methods for the safeguarding of ancient DNA -- a mine of valuable information for humanity.

In mummified specimens, DNA has often degraded and is present only in minimal amounts. In fact, faced with a new discovery, the first question experts encounter is how to examine the mummy while continuing to preserve it, without damaging its ancient DNA. Every action has irreversible consequences on DNA fragments, which makes experimenting with new techniques on human finds impossible. Contrastingly, an intact animal mummy is a perfect simulant for research -- especially if its conditions are similar to those of the world's other ice mummies, of which Ötzi and the Inca girl Juanita are among the most famous.

"Thanks to our previous studies we know the optimal physical and chemical parameters for preservation from a microbiological point of view. In the laboratory we will bring the chamois to those conditions and focus on their effects on DNA. With repeated in-depth analysis we will verify what alterations the DNA undergoes when external conditions change," explains Marco Samadelli, conservation expert at Eurac Research. "Our goal is to use scientific data to develop a globally valid conservation protocol for ice mummies. This is the first time an animal mummy has been used in this way," adds Albert Zink, Director of the Institute for Mummy Studies at Eurac Research.

Upon encountering the chamois, Hermann Oberlechner soon realised the importance of the find. "Only half of the animal's body was exposed from the snow. The skin looked like leather, completely hairless; I had never seen anything like it. I immediately took a photo and sent it to the park ranger, together we then notified the Department of Cultural Heritage."

The discovery site, at 3200 m MSL, is impassable and can only be reached by a six-hour hike. For this reason, following their initial inspection, the researchers decided to ask for the support of the Alpine Army Corps in the recovery of the animal. "The request from Eurac Research came during a training phase of our military mountain rescue team. We plan regular exercises not only in order to always be ready to intervene and protect our personnel in high-altitude missions, but also if we are requested for civil protection too." commented Mario Bisica, Alpine Army Corps Head of Public Information and Communication.

The helicopter flight was organised in collaboration with the army's specialised aviation corps, who have their own regiment in Bolzano, with pilots specifically trained to operate at high altitude. Thanks to the group effort, Eurac Research experts were able to reach the glacier and, with the help of the troops, carry out the scientific operation needed to recover the mummy. The chamois was then wrapped in an inert material casing made to measure by conservationist Marco Samadelli. The remains are now being kept at the Eurac Research Conservation Laboratory at NOI Techpark in refrigerated cell at -- 5 C°, ready to be studied.

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