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An international team of astronomers has discovered one of the largest features ever observed in the center of the Milky Way - a pair of enormous radio-emitting bubbles that tower hundreds of light-years above and below the central region of our galaxy.

This hourglass-like feature, which dwarfs all other radio structures in the galactic center, is likely the result of a phenomenally energetic burst that erupted near the Milky Way's supermassive black hole a few million years ago.

"The center of our galaxy is relatively calm when compared to other galaxies with very active central black holes," said Ian Heywood of the University of Oxford and lead author of an article appearing in the journal Nature. "Even so, the Milky Way's central black hole can - from time to time - become uncharacteristically active, flaring up as it periodically devours massive clumps of dust and gas. It's possible that one such feeding frenzy triggered powerful outbursts that inflated this previously unseen feature."

Using the South African Radio Astronomy Observatory (SARAO) MeerKAT telescope, Heywood and his colleagues mapped out broad regions in the center of the galaxy, conducting observations at wavelengths near 23 centimeters. Radio emission of this kind is generated in a process known as synchrotron radiation, in which electrons moving at close to the speed of light interact with powerful magnetic fields. This produces a characteristic radio signal that can be used to trace energetic regions in space. This radio light easily penetrates the dense clouds of dust that block visible light from the center of the galaxy.

By examining the nearly identical size and shape of the twin bubbles, the researchers think they have found convincing evidence that these features were formed from a violent eruption that over a short period of time punched through the interstellar medium in opposite directions.

"The shape and symmetry of what we have observed strongly suggests that a staggeringly powerful event happened a few million years ago very near our galaxy's central black hole," said William Cotton, an astronomer with the National Radio Astronomy Observatory in Charlottesville, Virginia, and co-author on the paper. "This eruption was possibly triggered by vast amounts of interstellar gas falling in on the black hole, or a massive burst of star formation which sent shockwaves careening through the galactic center. In effect, this inflated bubbles in the hot, ionized gas near the galactic center, energizing it and generating radio waves that we could eventually detect here on Earth."

The environment surrounding the black hole at the center of our galaxy is vastly different than the environment elsewhere in the Milky Way, and is a region of many mysteries. Among those are very long and narrow filaments found nowhere else, the origin of which has remained an unsolved puzzle since their discovery 35 years ago. The filaments appear as radio structures tens of light-years long and approximately a light-year wide.

"The radio bubbles discovered by MeerKAT now shed light on the origin of the filaments," said Farhad Yusef-Zadeh at Northwestern University in Evanston, Illinois, and a co-author on the paper. "Almost all of the more than one hundred filaments are confined by the radio bubbles."

The authors suggest that the close association of the filaments with the bubbles implies that the energetic event that created the radio bubbles is also responsible for accelerating the electrons required to produce the radio emission from the magnetized filaments.

"These enormous bubbles have until now been hidden by the glare of extremely bright radio emission from the center of the galaxy," said Fernando Camilo of SARAO in Cape Town, and co-author on the paper. "Teasing out the bubbles from the background noise was a technical tour de force, only made possible by MeerKAT's unique characteristics and ideal location," according to Camilo. "With this unexpected discovery we're witnessing in the Milky Way a novel manifestation of galaxy-scale outflows of matter and energy, ultimately governed by the central black hole."

According to the researchers, the discovery of these bubbles relatively nearby in the center of our home galaxy brings us one step closer to understanding spectacular activities that occur in more distant cousins of the Milky Way throughout the universe.

Using computational tools to investigate gene transcription networks in large collections of brain tissues, a scientific team has identified a gene that acts as a master regulator of schizophrenia during early human brain development. The findings may lay the groundwork for future treatments for the highly complex neuropsychiatric disorder.

"Because hundreds, or even thousands, of genes may contribute to the risk of schizophrenia, it is crucial to understand which are the most important ones, orchestrating core networks in the disease," said study leader Kai Wang, PhD, of the Department of Pathology and Laboratory Medicine and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics (CCMT) at Children's Hospital of Philadelphia (CHOP). "Pinpointing master regulators may help guide us toward priority targets for novel treatments in the future."

The study appeared online today in Science Advances. Wang co-led the research with Jubao Duan, PhD, the Charles R. Walgreen Research Chair and an associate professor at the Center for Psychiatric Genetics of North Shore University HealthSystem (NorthShore) and the University of Chicago, Evanston, Ill. The first author was Abolfazi Doostparast Torshizi, PhD, of the CCMT at CHOP.

Although schizophrenia affects about 1 in 100 adults, and is highly heritable, the genetic architecture of the neuropsychiatric disorder is notoriously complex, with many unsolved questions. Wang and colleagues contrast the current state of knowledge to recent advances in cancer research. Oncology researchers have identified many gene pathways and networks that when perturbed, result in specific types of cancer. That knowledge has permitted fine distinctions in diagnosing subsets among types of cancer, and has led to individualized treatments based on a patient's genetic profile.

The underlying genomic biology in neuropsychiatric disorders is likely more challenging. In the most extreme case, researchers have recently proposed an "omnigenic" model, in which nearly all the genes in a disease-relevant cell type contribute to a specific neuropsychiatric disorder, but Wang points out, "Not all the genes carry equal weight--the problem is to determine which are more important than others."

Thus, the study team used computational systems biology approaches to discern a disease-relevant core pathway in schizophrenia and to discover a master regulator in that pathway that affects hundreds of downstream genes.

Wang and colleagues analyzed two independent datasets of biological samples from schizophrenia patients and control subjects. One dataset, the CommonMind Consortium (CMC), is a public-private partnership with well-curated brain collections. The other was a collection of primary cultured neuronal cells derived from olfactory epithelium (CNON), generated by study co-authors at the University of Southern California and SUNY Downstate. The CMC dataset contained adult postmortem brain tissue, while the CNON dataset, used to validate findings from the CMC study, represented cell cultures that contain neuronal cells from nasal biopsies. Applying an algorithm developed at Columbia University to reconstruct gene transcription networks, the study team identified the gene TCF4 as a master regulator for schizophrenia.

Previous genome-wide association studies (GWAS) had indicated that TCF4 was a locus for schizophrenia risk, said Wang, but little was known of the gene's functional effects. The study team investigated those effects by knocking down, or decreasing, the gene's expression in neural progenitor cells and glutamatergic neurons derived from induced pluripotent stem cells in Duan's lab at NorthShore.

Observations on three different cell lines showed that, when knocked down, the predicted TCF4 regulatory networks were enriched for genes showing transcriptomic changes, as well as for genes involved in neuronal activity, schizophrenia risk genes having genome-wide significance, and schizophrenia-associated de novo mutations. Although some of the cellular effects of TCF4 dysregulation were previously shown in mice, Duan noted that the results from perturbing TCF4 gene networks in human stem cell models may be more relevant to the neurodevelopmental aspects of neuropsychiatric disorders.

The current study, said the researchers, sets the stage for further investigations. One direction, said Wang, is to use expanded datasets to explore whether other master regulators in addition to TCF4 may act in schizophrenia. If so, it may eventually be possible to classify patients with schizophrenia into subgroups more responsive to specific treatments, as is occurring in many cancers, to assist in implementing precision medicine in psychiatric diseases.

Other approaches, added Doostparast, may involve pursuing functional genomics at the level of single cells, to assess the cell types that are most influenced by dysregulating gene expression.

The study represents one of the first successful examples of combining computational approaches and stem cell-based experimental models to disentangle complex gene networks in psychiatric diseases.

Wang noted limitations in the study. The empirical validation focused on neural progenitor cells and glutamatergic neurons, but other cell types may be investigated in the future, such as interneurons and microglia, which have also been implicated in the development of schizophrenia.

Space agencies must invest more resources on field geology training of astronauts to take full advantage of scientific opportunities on the Moon and other planetary bodies, Kip Hodges and Harrison Schmitt urge, in an Editorial. The Moon represents a pristine archive of the early history of the Solar System, making it an ideal research target for scientists seeking a window into planetary formation. Key to the success of these efforts will be careful field geology prior to sample collection. Here, Hodges and Schmitt discuss whether space agencies are fully prepared to study these surfaces on future voyages to the Moon and Mars. They argue that conducting effective geological research on other planets will require extensive training, meaning that astronaut programs should place a stronger emphasis on field geology training of all astronauts and should include geologists with advanced degrees in mission crews. Furthermore, space agencies should develop aggressive research programs to develop new science operations strategies that integrate new technologies (e.g., augmented reality) to enable better field research. The authors recommend that both educational and research activities in this vein should involve scientists and engineers from academia as well as from the space agencies. Taking such steps will optimize the scientific productivity of missions to the Moon, Mars and beyond.

K2-18b, which is eight times the mass of Earth, is now the only planet orbiting a star outside the Solar System, or 'exoplanet', known to have both water and temperatures that could support life.

The discovery, published today in Nature Astronomy, is the first successful atmospheric detection for an exoplanet orbiting in its star's 'habitable zone', at a distance where water can exist in liquid form.

First author, Dr Angelos Tsiaras (UCL Centre for Space Exochemistry Data (CSED)), said: "Finding water in a potentially habitable world other than Earth is incredibly exciting. K2-18b is not 'Earth 2.0' as it is significantly heavier and has a different atmospheric composition. However, it brings us closer to answering the fundamental question: Is the Earth unique?"

The team used archive data from 2016 and 2017 captured by the ESA/NASA Hubble Space Telescope and developed open-source algorithms to analyse the starlight filtered through K2-18b's atmosphere. The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet's atmosphere.

The authors believe that other molecules including nitrogen and methane may be present but, with current observations, they remain undetectable. Further studies are required to estimate cloud coverage and the percentage of atmospheric water present.

The planet orbits the cool dwarf star K2-18, which is about 110 light years from Earth in the Leo constellation. Given the high level of activity of its red dwarf star, K2-18b may be more hostile than Earth and is likely to be exposed to more radiation.

K2-18b was discovered in 2015 and is one of hundreds of super-Earths - planets with a mass between Earth and Neptune - found by NASA's Kepler spacecraft. NASA's TESS mission is expected to detect hundreds more super-Earths in the coming years.

Co-author Dr Ingo Waldmann (UCL CSED), said: "With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets. This is not only because super-Earths like K2-18b are the most common planets in our Galaxy, but also because red dwarfs - stars smaller than our Sun - are the most common stars."

The next generation of space telescopes, including the NASA/ESA/CSA James Webb Space Telescope and ESA's ARIEL mission, will be able to characterise atmospheres in more detail as they will carry more advanced instruments. ARIEL is expected to launch in 2028, and will observe 1,000 planets in detail to get a truly representative picture of what they are like.

Professor Giovanna Tinetti (UCL CSED), co-author and Principal Investigator for ARIEL, said: "Our discovery makes K2-18 b one of the most interesting targets for future study. Over 4,000 exoplanets have been detected but we don't know much about their composition and nature. By observing a large sample of planets, we hope to reveal secrets about their chemistry, formation and evolution."

"This study contributes to our understanding of habitable worlds beyond our Solar System and marks a new era in exoplanet research, crucial to ultimately place the Earth, our only home, into the greater picture of the Cosmos," said Dr Tsiaras.

Secretary of State Andrea Leadsom said: "Space exploration is one of the greatest adventures of our time, and for decades, scientists and astronomers have scoured the skies for planets capable of supporting life. This discovery by UK researchers is a giant leap forward in this endeavour, opening a new world of possibilities. The secrets of our universe are out there, and I am enormously proud that our Government-backed researchers and councils are at the forefront of efforts to unlock answers to mysteries that have endured for centuries."

Chris Lee, the UK Space Agency’s Chief Scientist, said: "This exciting discovery demonstrates the UK’s leading strengths in the science of exoplanets.
"We continue to build on this expertise, with UCL at the heart of a new mission - ARIEL - to study the atmosphere of worlds orbiting other stars in our Galaxy. This is one of a number of international space science missions involving leading roles for UK science and industry and forms part of our ongoing commitment to the European Space Agency."

Dr Colin Vincent, Head of STFC’s Astronomy Division, said: "Finding other planets that might have the capability to support life is one of the holy grails of astronomy research. This result based on data from the Hubble Space Telescope gives an exciting taste of what may be possible in the next few years as a number of new telescopes and space missions supported by STFC and the UK Space Agency come online."

Scientists at Newcastle University have shown that patterns - particularly stripes which are easy to spot when an animal is still - can also help conceal speeding prey.

They tested out their theories on praying mantises in a specially constructed miniature cinema where they were played videos of rectangular shapes which imitated bugs moving across a background similar to the natural environment.

As they watched movies of the bugs moving at different speeds, the mantises would move their heads and follow the bugs across the screen, tracking them as if they were prey.

Some of the bugs had narrow or wide stripes, while others were patterned to match the background or had no pattern at all.

It's well known that some animals are patterned to match their background to reduce their chances of being detected by a predator. However, these patterns which hide them when they're stationary are much less effective once they start to move.

The scientists discovered that the mantises found it particularly hard to spot the patterned bugs with narrow stripes moving at faster speeds. This is because their stripes quickly become blurred to the predator and harder to see.

The work is published today in Current Biology.

Lead author, Professor Candy Rowe, professor of Animal Behaviour and Cognition at Newcastle University explained: "We wanted to answer a puzzle that scientists have been wondering about for a while - can a pattern lower the chances that moving prey is seen by a predator?

"If you're standing still, then looking like the background is one of the best ways to not be seen, whilst having high contrast stripes is just about the worst thing - you can really stand out. For moving prey, we find that the opposite is true: stripes are much better than matching your background. So the answer is yes, if you're stripy and move fast enough, then the blurring of the pattern can make it harder for the predator to spot you.

"While we did this experiment with praying mantises chasing rectangular bugs on a computer screen, the same principle should apply in the wild. So maybe stripes help to hide zebras running on the plains, or hoverflies flitting from flower to flower. Of course, these animals may use their stripes in other ways too when they're not moving - zebra stripes may help to ward off flies carrying deadly diseases and hoverflies probably benefit from looking like bees when they are sitting on flowers. But if they want to avoid being 'fast food' for a predator, being striped could really help."

So there may be something in the cartoon burglars who wear stripy tops so they can escape- just as long as they run fast enough!

Sustainable Development Goal (SDG) 2 calls for ending hunger, achieving food security and improved nutrition, and promoting sustainable agriculture. The environmental challenges posed by agriculture are however massive, and many fear that they will only become more pressing as we try to meet the growing need for food worldwide. IIASA researchers and colleagues from Japan propose alternative hunger eradication strategies that will not compromise environmental protection.

Despite encouraging progress made in reducing the number of people that go hungry worldwide, one in nine people remain undernourished, more than 30 million children under the age of five are dangerously underweight, and poor nutrition is responsible for the deaths of nearly 3.1 million children under five each year. Across the globe, an estimated 821 million people were undernourished in 2017, and by 2050, the world will likely have two billion more mouths to feed. One approach to meeting the dietary needs of a rapidly growing world population is by increasing food production through agricultural intensification and expansion. This will however inevitably have negative effects on the environment such as air and water pollution, biodiversity loss, and increased greenhouse gas emissions. At the same time, it is well known that hunger is much more a result of unequal access to food across populations, even within single countries where undernourishment often coexists with obesity, rather than lack of agricultural production overall. This fact is however too often forgotten when hunger eradication strategies are being considered.

In their study published in the journal Nature Sustainability, IIASA researchers collaborated with colleagues from Ritsumeikan University and the National Institute for Environmental Studies (NIES) in Japan to explore different ways to end hunger by reducing the inequalities in access to food rather than increasing agricultural production, thus reducing the potential conflicts with environmental protection.

The first alternative hunger eradication strategy explored in the study, focuses exclusively on bridging the nutrition gap of the undernourished population, which can be realized through targeted government support in the short-term. Such a strategy would include food and nutrition programs that provide food in-kind transfers, school-feeding programs, vouchers for food, income support programs, and safety-nets, without the need to wait for economic growth. This more immediate strategy is termed, support-led security. In this scenario, eradicating hunger by 2030, means providing sufficient food to an additional 410 million people who would otherwise remain undernourished under a business as usual scenario. When focusing on the undernourished only, the additional global agricultural production necessary would only be 3%, with corresponding limited negative effects on the environment.

These negligible effects are in strong contrast with an alternative scenario, where hunger eradication is achieved through a general increase in food consumption typically associated with sustained economic growth leading not only to a reduction in the prevalence of undernourishment, but also to an increase in over-consumption. Apart from the fact that such a strategy would not allow the timely achievement of SDG2 (2030), as many decades of economic growth would be necessary, it would require a seven times higher (+20%) growth in food production. This would in turn require 48 Mha of additional agricultural land and also increase greenhouse gas emissions by 550 Mt CO2eq/year in 2030.

"This paper demonstrates that providing enough food to the undernourished requires an only marginal increase in overall agricultural production and thus also has very limited trade-offs with the environment. Undernourishment is indeed not a problem of agricultural production capacity but of the current economic and political system. This means that there are no good excuses not to tackle it," says Center Head for Environmental Resources Development and Deputy Program Director of the Ecosystems Services and Management Program at IIASA, Petr Havlik, who is one of the authors of the study.

Additional analysis shows that if equity of food distribution is accompanied by a reduction in over-consumption and food waste, as well as improved agricultural intensification, undernutrition can be eradicated while at the same time reducing agricultural production, thus leading to multiple benefits for environmental sustainability.

"The required amount of food for hunger eradication and the negative impacts on the environment are much reduced by combining hunger eradication with improved equity in food distribution such as reduced food waste and over-consumption, together with agricultural research and development to increase crop yields in developing regions," says study lead-author Tomoko Hasegawa, a researcher at IIASA, Ritsumeikan University and NIES. "Our research shows that to achieve multiple goals, only one policy is not enough. We need to combine different policies to avoid unintended negative impacts on others. This implies that to end hunger without pressuring the environment, we need not only policies that address hunger, but also policies related to food waste and over-consumption, as well as ones related to agricultural research and development to increase crop yields in developing regions."

An international team of scientists, led by researchers at McMaster University, has solved a centuries-old mystery of 'Fraser's Clawed Frog', an unusual and elusive species found in West Africa.

The findings, published today in the journal PLOS ONE, dispel previous myths and shed new light on Xenopus fraseri including its geographic origin, evolutionary relationships, ecology, and distinctive species traits.

Two specimens of the frog, with a distinctive combination of four claws on the hind legs as well as small bony protrusions on the roof of their mouths known as vomerine teeth, were collected by British zoologist Louis Fraser in 1852 and housed at the Natural History Museum (NHM) in London.

In 1905, Fraser's clawed frog was designated as a distinct species, but its place on the evolutionary tree, geographic distribution, and ecology has since stumped scientists --due to a lack of genetic samples and poor records of its origin.

"The ancient condition of the only two specimens available to us posed many challenges for understanding its distinctiveness using DNA and knowing exactly where they came from" explains Ben Evans, lead author of the study and a professor of biology at McMaster University.

"The accurate identification of species is so important because it allows us to study change in populations, better understand how evolution occurs, and explore the processes that drive diversification, extinction and adaption," he says.

The team, which included researchers from the NHM, the Max Planck Institute in Germany and the University of Florida, used sensitive techniques -similar to approaches used to sequence the genomes of Neanderthals--to sequence the mitochondrial genome from the delicate specimens.

In addition, scientists sequenced complete or nearly complete mitochondrial genomes from 29 other Xenopus species, used high-resolution CT scanning to compare the internal and external anatomy of these and other specimens and, through intensive field work, managed to collect additional specimens of Fraser's frog in several remote regions of West Africa.

By doing so, they determined Fraser's Clawed Frog was indeed distinct from all others. And while it was previously thought to have lived in lowland tropical forests in West Africa, researchers found it actually inhabits the relatively hot and arid regions of northern Cameroon and northern Ghana.

"Obtaining DNA from specimens that have been preserved in spirit for well over a hundred years is something that has only become achievable in the last few decades. The recent advances in DNA extraction and sequencing are allowing us to revisit specimens and challenge assumptions made in the past," says Jeff Streicher, senior curator of amphibians and reptiles at the NHM.

In the summer of 2020, the team plans to travel to Nigeria to continue their efforts to understand biodiversity and genome evolution of African clawed frogs.

A pioneering investigation developed by the Universidad Carlos III de Madrid (UC3M) alongside the University of Sussex and University College London, shows that olfactory stimuli combined with auditory stimuli can change our perception of our body. These results provide new knowledge in the field of cognitive neuroscience and human-computer interaction.

People feel thinner and lighter when exposed to the smell of lemon, while feeling heavier and more corpulent when they smell vanilla. This is one of the results of the investigation recorded in the article "As Light As Your Scent: Effects of Smell and Sound on Body Image Perception", which explores the relation between smell and body shape.

The research team has demonstrated that the image we have of our own body changes depending on the stimuli we encounter, such as olfactory. Exposure to different smells can make us feel slimmer or more corpulent.

Another sense that influences this is hearing. Through a device adapted to a pair of shoes, developed by the UC3M in 2015 in collaboration with University College London and the University of London's School of Advanced Study, they have analysed how our perception of our body changes when the frequency spectrum of steps taken during physical activity was modified in real-time. "By increasing high frequencies, people feel lighter, happier, walk in a more active way and as a result, they find it easier to exercise", explains Ana Tajadura-Jiménez, a lecturer in the Computer Science and Engineering Department at the UC3M and one of the authors of both investigations.

This technology, based on the audio stimulus, that was used successfully both in 2017 to treat people with chronic pain and in 2019 to promote physical activity, is combined with olfactory stimuli in the current investigation to show that both senses combined have a large influence over the perception we have of our body image. "Image distortions can cause detriments to physical and emotional well-being. The research in cognitive neuroscience has shown that peoples' perception of their bodies can be changed through visual, tactile, proprioceptive and audio stimulation", points out Tajadura-Jiménez.

These results will allow new and more effective therapies to be designed, such as virtual reality experiences or the development of interactive clothes or portable technology, for people suffering from body image disorders in order to improve their self-esteem and re-calibrate distorted feelings about their body weight.

In the future, the aim is to carry out research in a clinical setting (as the current test was carried out on healthy people), to determine if the effects differ according to gender and to try out the effects of other kinds of scents.

If you want to build the most accurate clock in the world, you need something that "ticks" very fast and extremely precise. In an atomic clock, electrons are used, which can be switched back and forth between two different states in a very precisely defined way. Even more precise, however, would be a nuclear clock that does not use states of electrons, but internal states of the atomic nucleus.

For decades, people have been searching for suitable atomic nuclei for this purpose, and for a long time it had been conjectured that a specific thorium isotope must have a nuclear state that would be suitable for the construction of a new generation of high-precision clocks. This long-sought core state of thorium has now been demonstrated experimentally for the first time - twice, by two different international research teams. TU Wien played a significant role in both experiments. The results of the two experiments have now been published simultaneously in the journal "Nature".

Two adjacent energy levels

"In nuclear physics we usually have to deal with very high energies", says Prof. Thorsten Schumm from TU Wien. "The energies of the electrons orbiting the atomic nucleus are usually much lower, so it is relatively easy to manipulate these electrons with laser light. This is usually not possible with atomic nuclei".

Thorium nuclei of the isotope 229, however, are a remarkable exception: "Just above the ground state - the state with the smallest possible energy - there is, surprisingly, another nuclear state, which we call isomer," says Thorsten Schumm. The energy difference between these two nuclear states - the ground state and the isomer - is many orders of magnitude smaller than the difference between energy levels in other atomic nuclei. It is comparable to the energies of electrons. Thorium-229 is currently the only nucleus with such a low-energy isomer state.

The transition between the two thorium nuclear states is an excellent basis for constructing a novel precision clock. Nuclear states can be measured even more precisely than electron shell states as used in today's atomic clocks. Also, the atomic nucleus is much better protected against perturbations, for instance from external electromagnetic fields. Until now, the great problem was that the exact energy value of the unusual thorium isomer state was unknown.

Complicated measurement method

Because the search for this core condition is complicated and time-consuming, several teams joined forces: Research groups from Germany and Austria (LMU München, MPI Heidelberg, and TU Wien) developed a method to detect the desired isomer state: When radioactive uranium 233 nuclei decay, electrically charged thorium ions are formed - about 2% of them end up in the desired excited isomeric state. In order to electrically neutralize these thorium ions again, they are guided through a thin graphene layer, from which the thorium ions capture the missing electrons. The neutral thorium atoms can then spontaneously change from the excited nuclear state to the ground state. This releases energy: An electron is hurled away. The energy of this electron is measured - and if all details of the complicated experiment can be precisely controlled and calculated, the energy of the thorium nucleus state can be deduced. Thorsten Schumm and Simon Stellmer helped to develop the experiment, Florian Libisch and Christoph Lemell carried out computer simulations required for a quantitative estimate of the isomer energy.

At the same time, a completely different experiment was carried out in Japan, and Thorsten Schumm from the TU Wien was involved in this work too. There, a synchrotron was used which produces extremely intense X-rays. If thorium nuclei are irradiated with these rays, they can be transferred to the second excited nuclear state with an energy over 1000 times higher than the isomer state. From this state, the thorium nuclei then decay predominantly into the desired isomeric state, close to the ground state - the atoms are actively "pumped" into the isomer state and can be measured there.

Numerous possible applications

"This is an extremely important step for us: not only do we know that the excited state actually exists just above the ground state, we also know its energy quite well now," says Thorsten Schumm. In further measurements, the state will be measured even more precisely. Then it should be possible to use it for building compact, high-precision atomic nuclear clocks. Such clocks would open up completely new research possibilities: They would be a great tool for basic research, for example to investigate dark matter or to measure whether our natural constants are actually exactly constant. In addition to that, an atomic nuclear clock would make many other measurements more precise, which may only be indirectly related to measuring time. These include the measurement of tiny irregularities in the Earth's gravitational field or the more precise positioning of objects using satellite-based navigation.

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If Albert Einstein's theory of general relativity holds true, then a black hole, born from the cosmically quaking collisions of two massive black holes, should itself "ring" in the aftermath, producing gravitational waves much like a struck bell reverbates sound waves. Einstein predicted that the particular pitch and decay of these gravitational waves should be a direct signature of the newly formed black hole's mass and spin.

Now, physicists from MIT and elsewhere have "heard" the ringing of an infant black hole for the first time, and found that the pattern of this ringing does, in fact, predict the black hole's mass and spin -- more evidence that Einstein was right all along.

The findings, published today in Physical Review Letters, also favor the idea that black holes lack any sort of "hair" -- a metaphor referring to the idea that black holes, according to Einstein's theory, should exhibit just three observable properties: mass, spin, and electric charge. All other characteristics, which the physicist John Wheeler termed "hair," should be swallowed up by the black hole itself, and would therefore be unobservable.

The team's findings today support the idea that black holes are, in fact, hairless. The researchers were able to identify the pattern of a black hole's ringing, and, using Einstein's equations, calculated the mass and spin that the black hole should have, given its ringing pattern. These calculations matched measurements of the black hole's mass and spin made previously by others.

If the team's calculations deviated significantly from the measurements, it would have suggested that the black hole's ringing encodes properties other than mass, spin, and electric charge -- tantalizing evidence of physics beyond what Einstein's theory can explain. But as it turns out, the black hole's ringing pattern is a direct signature of its mass and spin, giving support to the notion that black holes are bald-faced giants, lacking any extraneous, hair-like properties.

"We all expect general relativity to be correct, but this is the first time we have confirmed it in this way," says the study's lead author, Maximiliano Isi, a NASA Einstein Fellow in MIT's Kavli Institute for Astrophysics and Space Research. "This is the first experimental measurement that succeeds in directly testing the no-hair theorem. It doesn't mean black holes couldn't have hair. It means the picture of black holes with no hair lives for one more day."

A chirp, decoded

On Sept. 9, 2015, scientists made the first-ever detection of gravitational waves -- infinitesimal ripples in space-time, emanating from distant, violent cosmic phenomena. The detection, named GW150914, was made by LIGO, the Laser Interferometer Gravitational-wave Observatory. Once scientists cleared away the noise and zoomed in on the signal, they observed a waveform that quickly crescendoed before fading away. When they translated the signal into sound, they heard something resembling a "chirp."

Scientists determined that the gravitational waves were set off by the rapid inspiraling of two massive black holes. The peak of the signal -- the loudest part of the chirp -- linked to the very moment when the black holes collided, merging into a single, new black hole. While this infant black hole likely gave off gravitational waves of its own, its signature ringing, physicists assumed, would be too faint to decipher amid the clamor of the initial collision.

Isi and his colleagues, however, found a way to extract the black hole's reverberation from the moments immediately after the signal's peak. In previous work led by Isi's co-author, Matthew Giesler, the team showed through simulations that such a signal, and particularly the portion right after the peak, contains "overtones" -- a family of loud, short-lived tones. When they reanalyzed the signal, taking overtones into account, the researchers discovered that they could successfully isolate a ringing pattern that was specific to a newly formed black hole.

In the team's new paper, the researchers applied this technique to actual data from the GW150914 detection, concentrating on the last few milliseconds of the signal, immediately following the chirp's peak. Taking into account the signal's overtones, they were able to discern a ringing coming from the new, infant black hole. Specifically, they identified two distinct tones, each with a pitch and decay rate that they were able to measure.

"We detect an overall gravitational wave signal that's made up of multiple frequencies, which fade away at different rates, like the different pitches that make up a sound," Isi says. "Each frequency or tone corresponds to a vibrational frequency of the new black hole."

Listening beyond Einstein

Einstein's theory of general relativity predicts that the pitch and decay of a black hole's gravitational waves should be a direct product of its mass and spin. That is, a black hole of a given mass and spin can only produce tones of a certain pitch and decay. As a test of Einstein's theory, the team used the equations of general relativity to calculate the newly formed black hole's mass and spin, given the pitch and decay of the two tones they detected.

They found their calculations matched with measurements of the black hole's mass and spin previously made by others. Isi says the results demonstrate that researchers can, in fact, use the very loudest, most detectable parts of a gravitational wave signal to discern a new black hole's ringing, where before, scientists assumed that this ringing could only be detected within the much fainter end of the gravitational wave signal, and only with much more sensitive instruments than what currently exist.

"This is exciting for the community because it shows these kinds of studies are possible now, not in 20 years," Isi says.

As LIGO improves its resolution, and more sensitive instruments come online in the future, researchers will be able to use the group's methods to "hear" the ringing of other newly born black holes. And if they happen to pick up tones that don't quite match up with Einstein's predictions, that could be an even more exciting prospect.

"In the future, we'll have better detectors on Earth and in space, and will be able to see not just two, but tens of modes, and pin down their properties precisely," Isi says. "If these are not black holes as Einstein predicts, if they are more exotic objects like wormholes or boson stars, they may not ring in the same way, and we'll have a chance of seeing them."

University of Colorado Boulder engineers and faculty from the Consortium for Fibrosis Research & Translation (CFReT) at the University of Colorado Anschutz Medical Campus have teamed up to develop biomaterial-based "mimics" of heart tissues to measure patients' responses to an aortic valve replacement procedure, offering new insight into the ways that cardiac tissue re-shapes itself post-surgery.

Aortic valve stenosis (AVS), a progressive disease characterized by heart valve tissue stiffening and obstructed blood flow from the heart, is known as a "silent killer," affecting 12.4 percent of the population over 75 years old with a mortality range of 2-5 years if left untreated. Transcatheter aortic valve replacement (TAVR) procedures, which place an artificial valve at the site of the blockage, have been widely and successfully adopted as a remedy in recent decades.

Details of the broader biological reaction to the valve replacement have remained largely unknown, but nevertheless hold significant ramifications for quantifying the quality of recovery, the risk of complications and the assessment of overall patient outcomes.

During AVS disease progression, tissue-specific cells known as fibroblasts transition into myofibroblasts, which promote tissue stiffening. The researchers were interested in understanding how and why, post TAVR, myofibroblasts revert to the more benign fibroblasts.

"Previous studies have shown significant remodeling of cardiac tissues post-intervention," said Dr. Brian Aguado, lead author of the study and a post-doctoral researcher in CU Boulder's Department of Chemical and Biological Engineering. "Our hypothesis was that perhaps there are biochemical cues in a patient's blood that may revert myofibroblasts back to fibroblasts."

Modeling such a transformation in the lab is one thing, Aguado said, but the key to the new study was obtaining blood samples from real AVS patients and then using biomaterials to replicate the microenvironment of the heart.

"The heart is not made of plastic like a petri dish is," he said. "We needed to engineer materials that could reflect the various stiffnesses of both healthy and diseased valve and cardiac tissue."

The researchers collected blood serum samples from AVS patients both pre- and post-TAVR procedure and then treated cardiac cells cultured in a customized hydrogel environment, maintaining a near-facsimile of the in vivo cardiac conditions before and after TAVR.

The researchers were able to quantify protein expression in patient sera, identifying key proteins associated with myofibroblast deactivation as the aortic and cardiac tissue re-shapes and rebuilds itself after TAVR.

"Our lab is focused on engineering hydrogels as mimics of the extracellular tissue microenvironment," said Dr. Kristi Anseth, Distinguished Professor of Chemical and Biological Engineering and director of the Precision Biomaterials IRT. "The hydrogel system developed for these studies enable us to evaluate how patient-specific biochemical cues, found in human sera, can impact cellular phenotypes. Our patient-specific observations would not have been possible using conventional tissue culture plastic materials."

"Cardiac fibrosis due to excess deposition of extracellular matrix proteins is a massive problem," said Timothy McKinsey, professor of medicine and director of the CFReT, one of the programs supported through the University of Colorado School of Medicine's Transformational Research Funding initiative. "Among other things, fibrosis causes the heart to become stiff, impairing its ability to relax. We are excited about the potential of translating our current findings to develop innovative therapies for fibrotic diseases of the heart and vasculature."

The research may also yield future insight into the observed differences in recovery between men and women. Previous clinical studies have suggested that men seem to undergo more cardiac tissue remodeling post-TAVR, and the new data found that male cardiac cells do indeed see more pronounced myofibroblast reversal relative to female cells, though further research is needed to understand sex-specific differences in various clinical contexts.

"We were a bit surprised by the breadth of these findings," Aguado said. "We didn't think that a valve implant could have such a profound impact on the body systemwide. The connections between our engineered models and clinical data give strength to that conclusion."

Overall, Aguado said, the results show that TAVR procedures do indeed trigger a beneficial protein response and that biomaterial models together with clinical samples can provide a useful bridge toward identifying future therapeutic opportunities.

"We are getting better at engineering disease models, but we're reaching a crossroads where models can only do so much," he said. "The future will rely on using patient samples in conjunction with these models to better understand disease progression in a patient. In collaboration with physicians, we can see how our advances in the lab can be translated into identifying more effective treatments for patients."

UNIVERSITY PARK, Pa. -- Papillomavirus has traditionally been considered strictly a sexually transmitted disease, but a recent study found that rabbit and mouse papillomaviruses could be transferred by blood to their respective hosts.

Penn State researchers on the study said this raises the possibility that human papillomavirus (HPV) may also be transferable by blood in humans.

According to the Centers for Disease Control and Prevention, HPV is the most common sexually transmitted disease in humans, with an estimated 79 million individuals infected in the United States alone. While HPV is often harmless and goes away on its own, it can sometimes result in genital warts or progress to cervical or oral cancer.

Jiafen Hu, assistant professor of pathology and laboratory medicine at Penn State College of Medicine, said the team's results suggest more research is needed to determine whether HPV can be spread through blood in humans, specifically through blood transfusions.

"People who are receiving blood transfusions typically have immune systems that aren't working optimally, so their systems are more vulnerable," Hu said. "We might want to think about adding HPV to the list of viruses for which blood donations are screened, as well as researching whether the typical viral load of HPV in human blood would be sufficient to cause infection."

The results were recently published in the journal Emerging Microbes & Infections.

The study came about after an observation made in 2005 prompted one of the study authors to question how HPV is transmitted.

"Some years ago, researchers were looking at blood samples from a group of HIV-positive children, and as they were testing those samples, they found that some of them were also positive for HPV," Hu said. "Because these children were so young, it prompted the question of whether the virus could have come from blood transfusions, which some of the children had undergone."

While HPV is specific to humans and cannot be tested directly in animal models, the researchers said there are several different strains of papillomavirus that do exist in animals and can be a good approximation of how HPV may work in humans.

The researchers used two of these animal models for several experiments, including the Cottontail Rabbit Papillomavirus model, which the researchers said is considered to be the "gold standard" for studying HPV-related infections and diseases.

First, the researchers injected virus into the bloodstream of the rabbit. They monitored the rabbits, and after four weeks, noticed tumors on the animals, which Hu said demonstrated that the virus had traveled through the bloodstream and caused an infection.

Because their first experiment used a fairly large amount of the virus -- larger than would be present in a normal infection -- the researchers repeated the experiment with a five-fold reduction of the virus. The tumors once again appeared, this time on 18 out of 32 sites on the animals.

"We were able to show that the virus in the blood caused tumors, but what about blood transfusions?" Hu said. "People receiving a transfusion may only get a very small amount of the virus. To simulate this, we injected the virus into one animal, took 10 milliliters of blood and transfused it into a second animal. We still saw tumors."

While the rabbit model showed that the virus could travel through the bloodstream to cause infections in the skin, Hu said the question remained as to whether it could cause infections in mucous membranes, like the cervix.

The researchers repeated the experiments in a mouse model and found that not only did they detect the virus in mucous membranes like the tongue and genitals, but they also found it in the stomach. Hu noted that this was a significant finding because people with cancer are sometimes found to have papillomavirus sequences in their stomach and other internal organs.

Hu said that while HPV does not cause health problems for every person who becomes infected with the virus, it is still important to know whether or not it can be spread by blood.

"We know that HPV is common and that not everyone who gets it is going to get cancer," Hu said. "The tricky part is that a lot of people who are carrying HPV and are asymptomatic still have the potential to spread the virus. If a person is getting a blood transfusion because of one health issue, you don't want to accidentally add another on top of that."

The Acheulian culture endured in the Levant for over a million years during the Lower Paleolithic period (1.4 million to 400,000 years ago). Its use of bifaces or large cutting tools like hand axes and cleavers is considered a hallmark of its sophistication -- or, some researchers would argue, the lack thereof.

A new Tel Aviv University-led study published in Nature's Scientific Reports on September 10 reveals that these early humans also crafted tiny flint tools out of recycled larger discarded instruments as part of a comprehensive animal-butchery tool kit. This suggests that the Acheulians were, in fact, far more sophisticated than previously believed.

The international team of researchers, led by Dr. Flavia Venditti and Prof. Ran Barkai of TAU's Department of Archeology and Ancient Near Eastern Cultures together with colleagues from La Sapienza Rome University, discovered tiny flint flakes in the Lower Paleolithic Late Acheulian site of Revadim. In the past, this site yielded various stone assemblages, including dozens of hand axes, as well as animal remains, primarily of elephants.

The new research is based on expert analyses of 283 tiny flint items some 300,000-500,000 years old.

"The analysis included microscopic observations of use-wear as well as organic and inorganic residues," explains Dr. Venditti. "We were looking for signs of edge damage, striations, polishes, and organic residue trapped in depressions in the tiny flint flakes, all to understand what the flakes were used for."

According to the microscopic use signs and organic residue found on the tiny flakes, these flint specimens were not merely industrial waste left over from the production of larger tools. In addition, they were the deliberate product of recycled discarded artifacts and intended for a specific use.

"For decades, archaeologists did not pay attention to these tiny flakes. Emphasis was instead focused on large, elaborate hand axes and other impressive stone tools," says Prof. Barkai. "But we now have solid evidence proving the vital use of the two-inch flakes."

"We show here for the first time that the tiny tools were deliberately manufactured from recycled material and played an important role in the ancient human toolbox and survival strategies," adds Dr. Venditti.

The Acheulian culture, which was also prevalent in Africa, Europe, and Asia at the time, was characterized by the standard production of large impressive stone tools, mainly used in the butchery of the enormous animals that walked the earth.

"Ancient humans depended on the meat and especially the fat of animals for their existence and well-being. So the quality butchery of the large animals and the extraction of every possible calorie was of paramount importance to them," Prof. Barkai says.

According to the study, which was conducted over the course of three years, the tiny tools were used at stages of the butchery process that required precise cutting, such as tendon separation, meat carving and periosteum removal for marrow acquisition. Some 107 tiny flakes showed signs of processing animal carcasses. Eleven flakes also revealed organic and inorganic residues, mainly of bone but also of soft tissue. Experiments carried out with reproductions of the tools showed that the small flakes must have been used for delicate tasks, performed in tandem with larger butchery tools.

"We have an image of ancient humans as bulky, large creatures who attacked elephants with large stone weapons. They then gobbled as much of these elephants as they could and went to sleep," Prof. Barkai says. "In fact, they were much more sophisticated than that. The tiny flakes acted as surgical tools created and used for delicate cutting of exact parts of elephants' as well as other animals' carcasses to extract every possible calorie.

"Nothing was wasted. Discarded stone tools were recycled to produce new tiny cutting implements. This reflects a refined, accurate, thoughtful, and environmentally conscious culture. This ecological awareness allowed ancient humans to thrive for thousands of years."

A newly developed type of architected metamaterial has the ability to change shape in a tunable fashion.

While most reconfigurable materials can toggle between two distinct states, the way a switch toggles on or off, the new material's shape can be finely tuned, adjusting its physical properties as desired. The material, which has potential applications in next-generation energy storage and bio-implantable micro-devices, was developed by a joint Caltech-Georgia Tech-ETH Zurich team in the lab of Julia R. Greer.

Greer, the Ruben F. and Donna Mettler Professor of Materials Science, Mechanics and Medical Engineering in Caltech's Division of Engineering and Applied Science, creates materials out of micro- and nanoscale building blocks that are arranged into sophisticated architectures that can be periodic, like a lattice, or non-periodic in a tailor-made fashion, giving them unusual physical properties.

Most materials that are designed to change shape require a persistent external stimulus to change from one shape to another and stay that way: for example, they may be one shape when wet and a different shape when dry--like a sponge that swells as it absorbs water.

By contrast, the new nanomaterial deforms through an electrochemically driven silicon-lithium alloying reaction, meaning that it can be finely controlled to attain any "in-between" states, remain in these configurations even upon the removal of the stimulus, and be easily reversed. Apply a little current, and a resulting chemical reaction changes the shape by a controlled, small degree. Apply a lot of current, and the shape changes substantially. Remove the electrical control, and the configuration is retained--just like tying off a balloon. A description of the new type of material was published online by the journal Nature on September 11.

Defects and imperfections exist in all materials, and can often determine a material's properties. In this case, the team chose to take advantage of that fact and build in defects to imbue the material with the properties they wanted.

"The most intriguing part of this work to me is the critical role of defects in such dynamically responsive architected materials," says Xiaoxing Xia, a graduate student at Caltech and lead author of the Nature paper.

For the Nature paper, the team designed a silicon-coated lattice with microscale straight beams that bend into curves under electrochemical stimulation, taking on unique mechanical and vibrational properties. Greer's team created these materials using an ultra-high-resolution 3D printing process called two-photon lithography. Using this novel fabrication method, they were able to build in defects in the architected material system, based on a pre-arranged design. In a test of the system, the team fabricated a sheet of the material that, under electrical control, reveals a Caltech icon.

"This just further shows that materials are just like people, it's the imperfections that make them interesting. I have always had a particular liking for defects, and this time Xiaoxing managed to first uncover the effect of different types of defects on these metamaterials and then use them to program a particular pattern that would emerge in response to electrochemical stimulus," says Greer.

A material with such a finely controllable ability to change shape has potential in future energy storage systems because it provides a pathway to create adaptive energy storage systems that would enable batteries, for example, to be significantly lighter, safer, and to have substantially longer lives, Greer says. Some battery materials expand when storing energy, creating a mechanical degradation due to stress from the repeated expanding and contracting. Architected materials like this one can be designed to handle such structural transformations.

"Electrochemically active metamaterials provide a novel pathway for development of next generation smart batteries with both increased capacity and novel functionalities. At Georgia Tech, we are developing the computational tools to predict this complex coupled electro-chemo-mechanical behavior," says Claudio V. Di Leo, assistant professor of aerospace engineering at the Georgia Institute of Technology.