Researchers hunt for one-pole magnets by combining cosmic rays and particle accelerators

Some of the world's most powerful particle accelerators have helped researchers draw new leading limits on the existence of long theorized magnetic monopoles from the collisions of energetic cosmic rays bombarding the Earth's atmosphere, reports a new study published in Physical Review Letters.

Magnets are intimately familiar to everyone, with wide-ranging applications within daily life, from TVs and computers to kids toys. However, breaking any magnet, such as a navigation compass needle consisting of north and south poles in half, will result in just two smaller two-pole magnets. This mystery has eluded researchers for decades since 1931, when physicist Paul Dirac theorized the existence of one-pole "magnetic monopoles'' -- particles comparable to electrons but with a magnetic charge.

To explore whether magnetic monopoles exist, an international team of researchers, including the University of Tokyo's Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU) Fellow Volodymyr Takhistov, studied available data from a variety of terrestrial experiments and have carried out the most sensitive searches to date for monopoles over a broad range of possible masses. The researchers focused on an unusual source of monopoles -- atmospheric collisions of cosmic rays that have been occurring for eons.

The interdisciplinary research required bringing together expertise from several distinct corners of science -- including accelerator physics, neutrino interactions and cosmic rays.

Cosmic ray collisions with the atmosphere have already played a central role in advancing science, especially the exploration of ghostly neutrinos. This lead to Kavli IPMU Senior Fellow Takaaki Kajita's 2015 Nobel Prize in Physics for the discovery by the Super-Kamiokande experiment that neutrinos oscillate in flight, implying that they have mass.

Partially inspired by the results of Super-Kamiokande, the team set to work on monopoles. Particularly intriguing were light monopoles with masses around the electroweak scale, which can be readily accessible to conventional particle accelerators.

By carrying out simulations of cosmic ray collisions, analogously to particle collisions at the LHC at CERN, the researchers obtained a persistent beam of light monopoles raining down upon different terrestrial experiments.

This unique source of monopoles is especially interesting, as it is independent of any pre-existing monopoles such as those potentially left over as relics from the early Universe, and covers a broad range of energies.

By re-analyzing data from a wide range of previous experimental monopole searches, the researchers identified novel limits on monopoles across a wide range of masses, including those beyond the reach of conventional collider monopole searches.

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Siberian tundra could virtually disappear by mid-millennium

Due to global warming, temperatures in the Arctic are climbing rapidly. As a result, the treeline for Siberian larch forests is steadily advancing to the north, gradually supplanting the broad expanses of tundra which are home to a unique mix of flora and fauna. Experts from the Alfred Wegener Institute have now prepared a computer simulation of how these woods could spread in the future, at the tundra's expense. Their conclusion: only consistent climate protection measures will allow roughly 30 percent of the Siberian tundra to survive to mid-millennium. In all other, less favourable scenarios, the unique habitat is projected to disappear entirely. The study was just released in the journal eLife.

The climate crisis can especially be felt in the Arctic: in the High North, the average air temperature has risen by more than two degrees Celsius over the past 50 years -- far more than anywhere else. And this trend will only continue. If ambitious greenhouse-gas reduction measures (Emissions Scenario RCP 2.6) are taken, the further warming of the Arctic through the end of the century could be limited to just below two degrees. According to model-based forecasts, if the emissions remain high (Scenario RCP 8.5), we could see a dramatic rise in the average summer temperatures in the Arctic -- by up to 14 degrees Celsius over today's norm by 2100.

"For the Arctic Ocean and the sea ice, the current and future warming will have serious consequences," says Prof Ulrike Herzschuh, Head of the Polar Terrestrial Environmental Systems Division at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). "But the environment on land will also change drastically. The broad expanses of tundra in Siberia and North America will be massively reduced, as the treeline, which is already slowly changing, rapidly advances northward in the near future. In the worst-case scenario, there will be virtually no tundra left by the middle of the millennium. In the course of our study, we simulated this process for the tundra in northeast Russia. The central question that concerned us was: which emissions path does humanity have to follow in order to preserve the tundra as a refuge for flora and fauna, as well its role for the cultures of indigenous peoples and their traditional ties to the environment?"

The tundra is home to a unique community of plants, roughly five percent of which are endemic, i.e., can only be found in the Arctic. Typical species include the mountain avens, Arctic poppy and prostrate shrubs like willows and birches, all of which have adapted to the harsh local conditions: brief summers and long, arduous winters. It also offers a home for rare species like reindeer, lemmings and insects like the Arctic bumblebee.

For their simulation, Ulrike Herzschuh and AWI modeller Dr Stefan Kruse employed the AWI vegetation model LAVESI. "What sets LAVESI apart is that it allows us to display the entire treeline at the level of individual trees," Kruse explains. "The model portrays the entire lifecycle of Siberian larches in the transition zone to the tundra -- from seed production and distribution, to germination, to fully grown trees. In this way, we can very realistically depict the advancing treeline in a warming climate."

The findings speak for themselves: the larch forests could spread northward at a rate of up to 30 kilometres per decade. The tundra expanses, which can't shift to colder regions due to the adjacent Arctic Ocean, would increasingly dwindle. Since trees aren't mobile and each one's seeds can only reach a limited distribution radius, initially the vegetation would significantly lag behind the warming, but then catch up to it again. In the majority of scenarios, by mid-millennium less than six percent of today's tundra would remain; saving roughly 30 percent would only be possible with the aid of ambitious greenhouse-gas reduction measures. Otherwise, Siberia's once 4,000-kilometre-long, unbroken tundra belt would shrink to two patches, 2,500 kilometres apart, on the Taimyr Peninsula to the west and Chukotka Peninsula to the east. Interestingly, even if the atmosphere cooled again in the course of the millennium, the forests would not completely release the former tundra areas.

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AI reveals unsuspected math underlying search for exoplanets

Artificial intelligence (AI) algorithms trained on real astronomical observations now outperform astronomers in sifting through massive amounts of data to find new exploding stars, identify new types of galaxies and detect the mergers of massive stars, accelerating the rate of new discovery in the world's oldest science.

But AI, also called machine learning, can reveal something deeper, University of California, Berkeley, astronomers found: unsuspected connections hidden in the complex mathematics arising from general relativity -- in particular, how that theory is applied to finding new planets around other stars.

In a paper appearing this week in the journal Nature Astronomy, the researchers describe how an AI algorithm developed to more quickly detect exoplanets when such planetary systems pass in front of a background star and briefly brighten it -- a process called gravitational microlensing -- revealed that the decades-old theories now used to explain these observations are woefully incomplete.

In 1936, Albert Einstein himself used his new theory of general relativity to show how the light from a distant star can be bent by the gravity of a foreground star, not only brightening it as seen from Earth, but often splitting it into several points of light or distorting it into a ring, now called an Einstein ring. This is similar to the way a hand lens can focus and intensify light from the sun.

But when the foreground object is a star with a planet, the brightening over time -- the light curve -- is more complicated. What's more, there are often multiple planetary orbits that can explain a given light curve equally well -- so called degeneracies. That's where humans simplified the math and missed the bigger picture.

The AI algorithm, however, pointed to a mathematical way to unify the two major kinds of degeneracy in interpreting what telescopes detect during microlensing, showing that the two "theories" are really special cases of a broader theory that, the researchers admit, is likely still incomplete.

"A machine learning inference algorithm we previously developed led us to discover something new and fundamental about the equations that govern the general relativistic effect of light- bending by two massive bodies," Joshua Bloom wrote in a blog post last year when he uploaded the paper to a preprint server, arXiv. Bloom is a UC Berkeley professor of astronomy and chair of the department.

He compared the discovery by UC Berkeley graduate student Keming Zhang to connections that Google's AI team, DeepMind, recently made between two different areas of mathematics. Taken together, these examples show that AI systems can reveal fundamental associations that humans miss.

"I argue that they constitute one of the first, if not the first time that AI has been used to directly yield new theoretical insight in math and astronomy," Bloom said. "Just as Steve Jobs suggested computers could be the bicycles of the mind, we've been seeking an AI framework to serve as an intellectual rocket ship for scientists."

"This is kind of a milestone in AI and machine learning," emphasized co-author Scott Gaudi, a professor of astronomy at The Ohio State University and one of the pioneers of using gravitational microlensing to discover exoplanets. "Keming's machine learning algorithm uncovered this degeneracy that had been missed by experts in the field toiling with data for decades. This is suggestive of how research is going to go in the future when it is aided by machine learning, which is really exciting."

Discovering exoplanets with microlensing

More than 5,000 exoplanets, or extrasolar planets, have been discovered around stars in the Milky Way, though few have actually been seen through a telescope -- they are too dim. Most have been detected because they create a Doppler wobble in the motions of their host stars or because they slightly dim the light from the host star when they cross in front of it -- transits that were the focus of NASA's Kepler mission. Little more than 100 have been discovered by a third technique, microlensing.

One of the main goals of NASA's Nancy Grace Roman Space Telescope, scheduled to launch by 2027, is to discover thousands more exoplanets via microlensing. The technique has an advantage over the Doppler and transit techniques in that it can detect lower-mass planets, including those the size of Earth, that are far from their stars, at a distance equivalent to that of Jupiter or Saturn in our solar system.

Bloom, Zhang and their colleagues set out two years ago to develop an AI algorithm to analyze microlensing data faster to determine the stellar and planetary masses of these planetary systems and the distances the planets are orbiting from their stars. Such an algorithm would speed analysis of the likely hundreds of thousands of events the Roman telescope will detect in order to find the 1% or fewer that are caused by exoplanetary systems.

One problem astronomers encounter, however, is that the observed signal can be ambiguous. When a lone foreground star passes in front of a background star, the brightness of the background stars rises smoothly to a peak and then drops symmetrically to its original brightness. It's easy to understand mathematically and observationally.

But if the foreground star has a planet, the planet creates a separate brightness peak within the peak caused by the star. When trying to reconstruct the orbital configuration of the exoplanet that produced the signal, general relativity often allows two or more so-called degenerate solutions, all of which can explain the observations.

To date, astronomers have generally dealt with these degeneracies in simplistic and artificially distinct ways, Gaudi said. If the distant starlight passes close to the star, the observations could be interpreted either as a wide or a close orbit for the planet -- an ambiguity astronomers can often resolve with other data. A second type of degeneracy occurs when the background starlight passes close to the planet. In this case, however, the two different solutions for the planetary orbit are generally only slightly different.

According to Gaudi, these two simplifications of two-body gravitational microlensing are usually sufficient to determine the true masses and orbital distances. In fact, in a paper published last year, Zhang, Bloom, Gaudi and two other UC Berkeley co-authors, astronomy professor Jessica Lu and graduate student Casey Lam, described a new AI algorithm that does not rely on knowledge of these interpretations at all. The algorithm greatly accelerates analysis of microlensing observations, providing results in milliseconds, rather than days, and drastically reducing the computer crunching.

Zhang then tested the new AI algorithm on microlensing light curves from hundreds of possible orbital configurations of star and exoplanet and noticed something unusual: There were other ambiguities that the two interpretations did not account for. He concluded that the commonly used interpretations of microlensing were, in fact, just special cases of a broader theory that explains the full variety of ambiguities in microlensing events.

"The two previous theories of degeneracy deal with cases where the background star appears to pass close to the foreground star or the foreground planet," Zhang said. "The AI algorithm showed us hundreds of examples from not only these two cases, but also situations where the star doesn't pass close to either the star or planet and cannot be explained by either previous theory. That was key to us proposing the new unifying theory."

Gaudi was skeptical, at first, but came around after Zhang produced many examples where the previous two theories did not fit observations and the new theory did. Zhang actually looked at the data from two dozen previous papers that reported the discovery of exoplanets through microlensing and found that, in all cases, the new theory fit the data better than the previous theories.

"People were seeing these microlensing events, which actually were exhibiting this new degeneracy but just didn't realize it," Gaudi said. "It was really just the machine learning looking at thousands of events where it became impossible to miss."

Zhang and Gaudi have submitted a new paper that rigorously describes the new mathematics based on general relativity and explores the theory in microlensing situations where more than one exoplanet orbits a star.

The new theory technically makes interpretation of microlensing observations more ambiguous, since there are more degenerate solutions to describe the observations. But the theory also demonstrates clearly that observing the same microlensing event from two perspectives -- from Earth and from the orbit of the Roman Space Telescope, for example -- will make it easier to settle on the correct orbits and masses. That is what astronomers currently plan to do, Gaudi said.

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How anesthetics affect brain functions

Modern anesthesia is one of the most important medical achievements. Whereas before, patients had to suffer hellish agonies during every operation, today anesthesia enables completely painless procedures. One feels nothing and can remember nothing afterwards. It is already known from electroencephalography (EEG) studies on patients that during anesthesia the brain is put into a deep sleep-like state in which periods of rhythmic electrical activity alternate with periods of complete inactivity. This state is called burst-suppression. Until now, it was unclear where exactly this state happens in the brain and which brain areas are involved.

However, this question is important to better understand the phenomenon and thus how the brain functions under anesthesia. Researchers from the Functional Imaging Unit at the German Primate Center (DPZ) -- Leibniz Institute for Primate Research in Göttingen have used functional magnetic resonance imaging (fMRI) to study the precise spatial distribution of synchronously working brain regions in anesthetized humans, long-tailed macaques, common marmosets and rats. They were able to show for the first time that the areas where burst-suppression is evident differ significantly in primates and rodents. While in rats large parts of the cerebral cortex synchronously show the burst-suppression pattern, in primates individual sensory regions, such as the visual cortex, are excluded from it.

"Our brain can be thought of as a full soccer stadium when we are awake," explains Nikoloz Sirmpilatze, a scientist in the Functional Imaging Unit and lead author of the study. "Our active neurons are like tens of thousands of spectators all talking at once. Under anesthesia, however, neuronal activity is synchronized. You can measure this activity using EEG as uniform waves, as if all the spectators in the stadium were singing the same song. In deep anesthesia, this song is repeatedly interrupted by periods of silence. This is called burst-suppression. The deeper the anesthesia, the shorter the phases of uniform activity, the bursts, and the longer the periodically recurring inactive phases, the so-called suppressions."

The phenomenon is caused by many different anesthetics, some of which vary in their mechanisms of action. And burst-suppression is also detectable in coma patients. However, it is not known whether this condition is a protective reaction of the brain or a sign of impaired functioning. It has also been unclear where in the brain burst-suppression occurs and which brain areas are involved, as localization by EEG alone is not possible.

To answer this question, Nikoloz Sirmpilatze and the researcher team used the imaging technique of fMRI. The method makes blood flow changes in the brain visible. The increased activity of neurons in a particular area of the brain leads to an increase in metabolism, followed by an increased blood and oxygen supply at this location, which is ultimately visible in the fMRI image.

In the first part of the study, the researchers established a system to evaluate fMRI data in humans, monkeys and rodents in a standardized manner using the same method. To do this, they used simultaneously-measured EEG and fMRI data from anesthetized patients that had been generated in a previously conducted study at the Technical University of Munich. "We first looked to see whether the burst-suppression detected in the EEG was also visible in the fMRI data and whether it showed a certain pattern," says Nikoloz Sirmpilatze. "Based on that, we developed a new algorithm that allowed detecting burst-suppression events in the experimental animals using fMRI, without additional EEG measurement."

The researchers then performed fMRI measurements in anesthetized long-tailed macaques, common marmosets and rats. In all animals, they were able to detect and precisely localize burst-suppression as a function of anesthetic concentration. The spatial distribution of burst-suppression showed that in both humans and monkey species, certain sensory areas, such as the visual cortex, were excluded from it. In contrast, in the rats, the entire cerebral cortex was affected by burst-suppression.

"At the moment, we can only speculate about the reasons," says Nikoloz Sirmpilatze, who was awarded the German Primate Center's 2021 PhD Thesis Award for his work. "Primates orient themselves mainly through their sense of sight. Therefore, the visual cortex is a highly specialized region that differs from other brain areas by special cell types and structures. In rats, this is not the case. In future studies, we will investigate what exactly happens in these regions during anesthesia to ultimately understand why burst-suppression is not detectable there with fMRI."

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Supermassive black holes inside of dying galaxies detected in early universe

An international team of astronomers used a database combining observations from the best telescopes in the world, including the Subaru Telescope, to detect the signal from the active supermassive black holes of dying galaxies in the early Universe. The appearance of these active supermassive black holes correlates with changes in the host galaxy, suggesting that a black hole could have far reaching effects on the evolution of its host galaxy.

The Milky Way Galaxy where we live includes stars of various ages, including stars still forming. But in some other galaxies, known as elliptical galaxies, all of the stars are old and about the same age. This indicates that early in their histories elliptical galaxies had a period of prolific star formation that suddenly ended. Why this star formation ceased in some galaxies but not others is not well understood. One possibility is that a supermassive black hole disrupts the gas in some galaxies, creating an environment unsuitable for star formation.

To test this theory, astronomers look at distant galaxies. Due to the finite speed of light, it takes time for light to travel across the void of space. The light we see from an object 10 billion light-years away had to travel for 10 billion years to reach Earth. Thus the light we see today shows us what the galaxy looked like when the light left that galaxy 10 billion years ago. So looking at distant galaxies is like looking back in time. But the intervening distance also means that distant galaxies look fainter, making study difficult.

To overcome these difficulties an international team led by Kei Ito at SOKENDAI in Japan used the Cosmic Evolution Survey (COSMOS) to sample galaxies 9.5-12.5 billion light-years away. COSMOS combines data taken by world leading telescopes, including the Atacama Large Millimeter/submillimeter Array (ALMA) and the Subaru Telescope. COSMOS includes radio wave, infrared light, visible light, and x-ray data.

The team first used optical and infrared data to identify two groups of galaxies: those with ongoing star formation and those where star formation has stopped. The x-ray and radio wave data signal-to-noise ratio was too weak to identify individual galaxies. So the team combined the data for different galaxies to produce higher signal to noise ratio images of "average" galaxies. In the averaged images, the team confirmed both x-ray and radio emissions for the galaxies without star formation. This is the first time such emissions have been detected for distant galaxies more than 10 billion light-years away. Furthermore, the results show that the x-ray and radio emissions are too strong to be explained by the stars in the galaxy alone, indicating the presence of an active supermassive black hole. This black hole activity signal is weaker for galaxies where star formation is ongoing.

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Climate change reveals unique artifacts in melting ice patches

One day more than 3000 years ago, someone lost a shoe at the place we today call Langfonne in the Jotunheimen mountains. The shoe is 28 cm long, which roughly corresponds to a modern size 36 or 37. The owner probably considered the shoe to be lost for good, but on 17 September 2007 it was found again -- virtually intact.

Sometime around 2000 BCE, a red-wing thrush died at Skirådalskollen in the Dovrefjell mountain range. Its small body quickly became buried under an ice patch. Upon emerging again 4,000 years later, its internal organs are still intact.

In recent years, hundreds of such discoveries have been made in ice patches, revealing traces of hunting, trapping, traffic, animals and plant life -- small, frozen moments of the past.

Exceptional discoveries every year

Norway has soil that is consistently quite acidic, which means that organic material from the past is poorly preserved in the soil. Glaciers often move -- and crush -- what they hide below the surface. Ice patches, on the other hand, are relatively stable and therefore create exceptional conditions for preserving organic material.

"Objects and remains of animals and human activity have been found that we didn't even know existed. They include everything from horse tack and clothing to arrows with tips made of shells, wooden shafts and feathers. Not a year goes by without surprising finds that shift the boundaries of our understanding," says Birgitte Skar, an archaeologist and associate professor at the NTNU (the Norwegian University of Science and Technology) University Museum. She is one of the researchers behind a new report (in Norwegian with an English summary) that summarizes the state of knowledge in Norway's glacial archaeology.

The report describes a variety of fabulous findings but also paints a gloomy picture.

Only a few ice patches containing potential discoveries have been investigated systematically over time, and they have hardly been studied at all in northern Norway.

Short-term financing results in a lack of continuity in monitoring and securing artefacts from the ice patches. Some research has been done on finds, but it barely scratches the surface. All the while, all this knowledge is melting away at record speed.

The most recent surveys from the Norwegian Water Resources and Energy Directorate (NVE) show that 364 square kilometres of Norwegian snow patches and glaciers have melted away since 2006.

Monitoring programme is overdue

"A survey based on satellite images taken in 2020 shows that more than 40 per cent of 10 selected ice patches with known finds have melted away. These figures suggest a significant threat for preserving discoveries from the ice, not to mention the ice as a climate archive," says Skar.

"The time is ripe for establishing a national monitoring programme using remote sensing and systematically securing archaeological finds and biological remains from ice patches. We should also use this programme to collect glaciological data from different parts of the country, since the ice patches can provide detailed data on how the climate has evolved over the last 7500 years," she said.

Unimaginable possibilities

The oldest find that has emerged from the ice in Norway is a 6100-year-old arrow shaft. Like the shoe, it was also found at Langfonne in the Jotunheimen mountain range.

Finds from here and several other places indicate that these areas were in continuous use as hunting grounds for as long as the ice has been there. This means that they offer an unparalleled archaeological source of information.

"We're beginning to assess whether the ice in some places might have survived the warm period following the last ice age, which would mean that the bottom layer of the ice could be remnants from the ice sheet from that period. This possibility offers unprecedented opportunities to trace climate history and activity on these hunting grounds even further back in time," Skar says.

"We have to remember that the oldest population group in Norway descended from reindeer hunters who hunted in Northern Europe and Southern Scandinavia close to the edge of the ice sheet, in the later part of the ice age. In other words, these are people who would have known how to hunt large cloven-hoofed animals and would understand the animals' behaviour patterns," Skar adds.

Reindeer seek out ice patches during hot and buggy summer weather, and the Sami population has also used these areas for a wide range of purposes, including calf marking, milking and separating the animals. However, the Sami use of inland ice has hardly been surveyed.

"The Sami uses would probably expand the known range of uses and significance of the snow patches. Obtaining information from these tradition bearers is urgent," says Skar.

Mummified birds and animals

Human activity through the millennia are not the only stories revealed by the ice patch finds. Animal and plant remains also provide new insights into the ice as an ecosystem, such as reindeer bones from 4200 years ago that still contain intact bone marrow, as well as several whole mummified mammals and birds.

According to Jørgen Rosvold, the findings are often very well preserved and can provide genetic information about several species far back in time. They can show how species have responded to climate change and human disturbances in the past.

Rosvold was also involved in the report. He is a biologist and assistant research director at the Norwegian Institute for Nature Research (NINA). He explains that ice is one of the world's least studied and understood ecosystems, so that we know very little about ice as a habitat.

"Our finds show that the ice in the mountains has provided important habitats for many mountain species for thousands of years through to the present day. The fauna finds also provide background information for the archaeological finds, for example by showing which species people might have hunted on the snow patches," says Rosvold.

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'Fuel of evolution' more abundant than previously thought in wild animals

The raw material for evolution is much more abundant in wild animals than we previously believed, according to new research from The Australian National University (ANU).

Darwinian evolution is the process by which natural selection results in genetic changes in traits that favour the survival and reproduction of individuals. The rate at which evolution occurs depends crucially on genetic differences between individuals.

Led by Dr Timothée Bonnet from ANU, an international research team wanted to know how much of this genetic difference, or "fuel of evolution," exists in wild animal populations. The answer: two to four times more than previously thought.

According to Dr Bonnet, the process of evolution that Darwin described was an incredibly slow one.

"However, since Darwin, researchers have identified many examples of Darwinian evolution occurring in just a few years," Dr Bonnet said.

"A common example of fast evolution is the peppered moth, which prior to the industrial revolution in the UK was predominantly white. With pollution leaving black soot on trees and buildings, black moths had a survival advantage because it was harder for birds to spot them.

"Because moth colour determined survival probability and was due to genetic differences, the populations in England quickly became dominated by black moths."

The study is the first time the speed of evolution has been systematically evaluated on a large scale, rather than on an ad hoc basis. The team of 40 researchers from 27 scientific institutions used studies of 19 populations of wild animals from around the world. These included superb fairy-wrens in Australia, spotted hyenas in Tanzania, song sparrows in Canada and red deer in Scotland.

"We needed to know when each individual was born, who they mated with, how many offspring they had, and when they died. Each of these studies ran for an average of 30 years, providing the team with an incredible 2.6 million hours of field data," Dr Bonnet said.

"We combined this with genetic information on each animal studied to estimate the extent of genetic differences in their ability to reproduce, in each population.

After three years of trawling through reams of data, Dr Bonnet and the team were able to quantify how much species change occurred due to genetic changes caused by natural selection.

"The method gives us a way to measure the potential speed of current evolution in response to natural selection across all traits in a population. This is something we have not been able to do with previous methods, so being able to see so much potential change came as a surprise to the team," Dr Bonnet said.

Professor Loeske Kruuk, also from ANU and now based at the University of Edinburgh in the United Kingdom, said: "This has been a remarkable team effort that was feasible because researchers from around the world were happy to share their data in a large collaboration.

"It also shows the value of long-term studies with detailed monitoring of animal life histories for helping us understand the process of evolution in the wild."

However, the researchers warn it's too early to tell whether the actual rate of evolution is getting quicker over time.

"Whether species are adapting faster than before, we don't know, because we don't have a baseline. We just know that the recent potential, the amount of 'fuel', has been higher than expected, but not necessarily higher than before," Dr Bonnet said.

According to the researchers, their findings also have implications for predictions of species' adaptability to environmental change.

"This research has shown us that evolution cannot be discounted as a process which allows species to persist in response to environmental change," Dr Bonnet said.

Dr Bonnet said that with climate change predicted to increase at an increasing rate, there is no guarantee that these populations will be able to keep up.

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Ancient viral elements embedded in human genome not from fossil retrovirus

Using a next generation sequencing analysis to examine human endogenous retrovirus (HERV) integration sites, researchers from Kumamoto University, the National Institute of Genetics (Japan), and the University of Michigan (USA) have discovered that these ancient retroviruses can undergo retrotransposition (DNA sequence insertion with RNA mediation) into iPS cells. The team believes that their discovery places a spotlight on a possible risk that HERVs pose when using iPS cells in regenerative medicine.

The study of ancient retroviruses embedded in our genome requires knowledge about our coexistence with viral threats throughout history. We know that HERVs occupy approximately 8% of the human genome and obtain mutations and deletions over long periods. HERVs are also expressed in early embryos and play several physiological roles in human development. For example, HERV-W and HERV-FRD Env proteins are important for placental formation, and HERV-K is thought to protect host cells from exogenous retrovirus infection. However, uncontrollable HERV-K expression is also thought to be associated with various diseases, including various cancers and neurological diseases, but the details of this association is not well known in humans.

Since no one has yet discovered replication competent HERVs in our genome, it is thought that they are from an extinct (fossil) virus. In their current work, the research team from Japan and the US discovered that HERV-K is expressed in SOX2-expressing cells, such as those in early embryos, cancer stem cells and iPS cells. They also found that some HERV-K are newly integrated into the host genome in the absence of Env, the viral envelope glycoprotein. This integration was dependent on reverse transcriptase, integrase and protease, thus the researchers hypothesized that the HERV-K embedded in our genome is actually not from a fossil virus, but moves on the genome through the synthesis of proviral DNA reverse transcription. Interestingly, when the researchers compared the HERV-K integration sites between iPS and fibroblast cells from the same donor, they found new HERV-K integration sites in iPS cells. However, the new integration sites were rarely preserved and disappeared during long-term culturing. HERV-K is likely to be randomly integrated into genome, thus the possibility remains that HERV-K retrotransposed-cells predominantly survive depending on their integration site.

The movement of HERV-K on the genome might cause cancer and neurological diseases by altering the gene expression profile. The researchers believe that the risk of HERV-K transposition is low in iPS cells but suggest that monitoring HERV-K integration sites should be seriously considered to improve the safety of regenerative medicine using iPS cells.

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New discovery about distant galaxies: Stars are more massive than we thought

A team of University of Copenhagen astrophysicists has arrived at a major result regarding star populations beyond the Milky Way. The result could change our understanding of a wide range of astronomical phenomena, including the formation of black holes, supernovae and why galaxies die.

For as long as humans have studied the heavens, how stars look in distant galaxies has been a mystery. In a study published today in The Astrophysical Journal, a team of researchers at the University of Copenhagen's Niels Bohr Institute is doing away with previous understandings of stars beyond our own galaxy.

Since 1955, it has been assumed that the composition of stars in the universe's other galaxies is similar to that of the hundreds of billions of stars within our own -- a mixture of massive, medium mass and low mass stars. But with the help of observations from 140,000 galaxies across the universe and a wide range of advanced models, the team has tested whether the same distribution of stars apparent in the Milky Way applies elsewhere. The answer is no. Stars in distant galaxies are typically more massive than those in our "local neighborhood." The finding has a major impact on what we think we know about the universe.

"The mass of stars tells us astronomers a lot. If you change mass, you also change the number of supernovae and black holes that arise out of massive stars. As such, our result means that we'll have to revise many of the things we once presumed, because distant galaxies look quite different from our own," says Albert Sneppen, a graduate student at the Niels Bohr Institute and first author of the study.

Analyzed light from 140,000 galaxies

Researchers assumed that the size and weight of stars in other galaxies was similar to our own for more than fifty years, for the simple reason that they were unable to observe them through a telescope, as they could with the stars of our own galaxy.

Distant galaxies are billions of light-years away. As a result, only light from their most powerful stars ever reaches Earth. This has been a headache for researchers around the world for years, as they could never accurately clarify how stars in other galaxies were distributed, an uncertainty that forced them to believe that they were distributed much like the stars in our Milky Way.

"We've only been able to see the tip of the iceberg and known for a long time that expecting other galaxies to look like our own was not a particularly good assumption to make. However, no one has ever been able to prove that other galaxies form different populations of stars. This study has allowed us to do just that, which may open the door for a deeper understanding of galaxy formation and evolution," says Associate Professor Charles Steinhardt, a co-author of the study.

In the study, the researchers analyzed light from 140,000 galaxies using the COSMOS catalog, a large international database of more than one million observations of light from other galaxies. These galaxies are distributed from the nearest to farthest reaches of the universe, from which light has traveled a full twelve billion years before being observable on Earth.

Massive galaxies die first

According to the researchers, the new discovery will have a wide range of implications. For example, it remains unresolved why galaxies die and stop forming new stars. The new result suggests that this might be explained by a simple trend.

"Now that we are better able to decode the mass of stars, we can see a new pattern; the least massive galaxies continue to form stars, while the more massive galaxies stop birthing new stars,. This suggests a remarkably universal trend in the death of galaxies," concludes Albert Sneppen.

The research was conducted at the Cosmic Dawn Center (DAWN), an international basic research center for astronomy supported by the Danish National Research Foundation. DAWN is a collaboration between the Niels Bohr Institute at the University of Copenhagen and DTU Space at the Technical University of Denmark.

The center is dedicated to understanding when and how the first galaxies, stars and black holes formed and evolved in the early universe, through observations using the largest telescopes along with theoretical work and simulations.

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Hot-blooded T. rex and cold-blooded Stegosaurus: Chemical clues reveal dinosaur metabolisms

For decades, paleontologists have debated whether dinosaurs were warm-blooded, like modern mammals and birds, or cold-blooded, like modern reptiles. Knowing whether dinosaurs were warm- or cold-blooded could give us hints about how active they were and what their everyday lives were like, but the methods to determine their warm- or cold-bloodedness -- how quickly their metabolisms could turn oxygen into energy -- were inconclusive. But in a new paper in Nature, scientists are unveiling a new method for studying dinosaurs' metabolic rates, using clues in their bones that indicated how much the individual animals breathed in their last hour of life.

"This is really exciting for us as paleontologists -- the question of whether dinosaurs were warm- or cold-blooded is one of the oldest questions in paleontology, and now we think we have a consensus, that most dinosaurs were warm-blooded," says Jasmina Wiemann, the paper's lead author and a postdoctoral researcher at the California Institute of Technology.

"The new proxy developed by Jasmina Wiemann allows us to directly infer metabolism in extinct organisms, something that we were only dreaming about just a few years ago. We also found different metabolic rates characterizing different groups, which was previously suggested based on other methods, but never directly tested," says Matteo Fabbri, a postdoctoral researcher at the Field Museum in Chicago and one of the study's authors.

People sometimes talk about metabolism in terms of how easy it is for someone to stay in shape, but at its core, "metabolism is how effectively we convert the oxygen that we breathe into chemical energy that fuels our body," says Wiemann, who is affiliated with Yale University and the Natural History Museum of Los Angeles County.

Animals with a high metabolic rate are endothermic, or warm-blooded; warm-blooded animals like birds and mammals take in lots of oxygen and have to burn a lot of calories in order to maintain their body temperature and stay active. Cold-blooded, or ectothermic, animals like reptiles breathe less and eat less. Their lifestyle is less energetically expensive than a hot-blooded animal's, but it comes at a price: cold-blooded animals are reliant on the outside world to keep their bodies at the right temperature to function (like a lizard basking in the sun), and they tend to be less active than warm-blooded creatures.

With birds being warm-blooded and reptiles being cold-blooded, dinosaurs were caught in the middle of a debate. Birds are the only dinosaurs that survived the mass extinction at the end of the Cretaceous, but dinosaurs (and by extension, birds) are technically reptiles -- outside of birds, their closest living relatives are crocodiles and alligators. So would that make dinosaurs warm-blooded, or cold-blooded?

Scientists have tried to glean dinosaurs' metabolic rates from chemical and osteohistological analyses of their bones. "In the past, people have looked at dinosaur bones with isotope geochemistry that basically works like a paleo-thermometer," says Wiemann -- researchers examine the minerals in a fossil and determine what temperatures those minerals would form in. "It's a really cool approach and it was really revolutionary when it came out, and it continues to provide very exciting insights into the physiology of extinct animals. But we've realized that we don't really understand yet how fossilization processes change the isotope signals that we pick up, so it is hard to unambiguously compare the data from fossils to modern animals."

Another method for studying metabolism is growth rate. "If you look at a cross section of dinosaur bone tissue, you can see a series of lines, like tree rings, that correspond to years of growth," says Fabbri. "You can count the lines of growth and the space between them to see how fast the dinosaur grew. The limit relies on how you transform growth rate estimates into metabolism: growing faster or slower can have more to do with the animal's stage in life than with its metabolism, like how we grow faster when we're young and slower when we're older."

The new method proposed by Wiemann, Fabbri, and their colleagues doesn't look at the minerals present in bone or how quickly the dinosaur grew. Instead, they look at one of the most basic hallmarks of metabolism: oxygen use. When animals breathe, side products form that react with proteins, sugars, and lipids, leaving behind molecular "waste." This waste is extremely stable and water-insoluble, so it's preserved during the fossilization process. It leaves behind a record of how much oxygen a dinosaur was breathing in, and thus, its metabolic rate.

The researchers looked for these bits of molecular waste in dark-colored fossil femurs, because those dark colors indicate that lots of organic matter are preserved. They examined the fossils using Raman and Fourier-transform infrared spectroscopy -- "these methods work like laser microscopes, we can basically quantify the abundance of these molecular markers that tell us about the metabolic rate," says Wiemann. "It is a particularly attractive method to paleontologists, because it is non-destructive."

The team analyzed the femurs of 55 different groups of animals, including dinosaurs, their flying cousins the pterosaurs, their more distant marine relatives the plesiosaurs, and modern birds, mammals, and lizards. They compared the amount of breathing-related molecular byproducts with the known metabolic rates of the living animals and used those data to infer the metabolic rates of the extinct ones.

The team found that dinosaurs' metabolic rates were generally high. There are two big groups of dinosaurs, the saurischians and the ornithischians -- lizard hips and bird hips. The bird-hipped dinosaurs, like Triceratops and Stegosaurus, had low metabolic rates comparable to those of cold-blooded modern animals. The lizard-hipped dinosaurs, including theropods and the sauropods -- the two-legged, more bird-like predatory dinosaurs like Velociraptor and T. rex and the giant, long-necked herbivores like Brachiosaurus -- were warm- or even hot-blooded. The researchers were surprised to find that some of these dinosaurs weren't just warm-blooded -- they had metabolic rates comparable to modern birds, much higher than mammals. These results complement previous independent observations that hinted at such trends but could not provide direct evidence, because of the lack of a direct proxy to infer metabolism.

These findings, the researchers say, can give us fundamentally new insights into what dinosaurs' lives were like.

"Dinosaurs with lower metabolic rates would have been, to some extent, dependent on external temperatures," says Wiemann. "Lizards and turtles sit in the sun and bask, and we may have to consider similar 'behavioral' thermoregulation in ornithischians with exceptionally low metabolic rates. Cold-blooded dinosaurs also might have had to migrate to warmer climates during the cold season, and climate may have been a selective factor for where some of these dinosaurs could live."

On the other hand, she says, the hot-blooded dinosaurs would have been more active and would have needed to eat a lot. "The hot-blooded giant sauropods were herbivores, and it would take a lot of plant matter to feed this metabolic system. They had very efficient digestive systems, and since they were so big, it probably was more of a problem for them to cool down than to heat up." Meanwhile, the theropod dinosaurs -- the group that contains birds -- developed high metabolisms even before some of their members evolved flight.

"Reconstructing the biology and physiology of extinct animals is one of the hardest things to do in paleontology. This new study adds a fundamental piece of the puzzle in understanding the evolution of physiology in deep time and complements previous proxies used to investigate these questions. We can now infer body temperature through isotopes, growth strategies through osteohistology, and metabolic rates through chemical proxies," says Fabbri.

In addition to giving us insights into what dinosaurs were like, this study also helps us better understand the world around us today. Dinosaurs, with the exception of birds, died out in a mass extinction 65 million years ago when an asteroid struck the Earth. "Having a high metabolic rate has generally been suggested as one of the key advantages when it comes to surviving mass extinctions and successfully radiating afterwards," says Wiemann -- some scientists have proposed that birds survived while the non-avian dinosaurs died because of the birds' increased metabolic capacity. But this study, Wiemann says, helps to show that this isn't true: many dinosaurs with bird-like, exceptional metabolic capacities went extinct.

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