Not all psychopaths are violent; a new study may explain why some are 'successful' instead

Psychopathy is widely recognized as a risk factor for violent behavior, but many psychopathic individuals refrain from antisocial or criminal acts. Understanding what leads these psychopaths to be "successful" has been a mystery.

A new study conducted by researchers at Virginia Commonwealth University sheds light on the mechanisms underlying the formation of this "successful" phenotype.

"Psychopathic individuals are very prone to engaging in antisocial behaviors but what our findings suggest is that some may actually be better able to inhibit these impulses than others," said lead author Emily Lasko, a doctoral candidate in the Department of Psychology in the College of Humanities and Sciences. "Although we don't know exactly what precipitates this increase in conscientious impulse control over time, we do know that this does occur for individuals high in certain psychopathy traits who have been relatively more 'successful' than their peers."

The study, "What Makes a 'Successful' Psychopath? Longitudinal Trajectories of Offenders' Antisocial Behavior and Impulse Control as a Function of Psychopathy," will be published in a forthcoming issue of the journal Personality Disorders: Theory, Research, and Treatment.

When describing certain psychopathic individuals as "successful" versus "unsuccessful," the researchers are referring to life trajectories or outcomes. A "successful" psychopath, for example, might be a CEO or lawyer high in psychopathic traits, whereas an "unsuccessful" psychopath might have those same traits but is incarcerated.

The study tests a compensatory model of "successful" psychopathy, which theorizes that relatively "successful" psychopathic individuals develop greater conscientious traits that serve to inhibit their heightened antisocial impulses.

"The compensatory model posits that people higher in certain psychopathic traits (such as grandiosity and manipulation) are able to compensate for and overcome, to some extent, their antisocial impulses via increases in trait conscientiousness, specifically impulse control," Lasko said.

To test this model, the researchers studied data collected about 1,354 serious juvenile offenders who were adjudicated in court systems in Arizona and Pennsylvania.

"Although these participants are not objectively 'successful,' this was an ideal sample to test our hypotheses for two main reasons," the researchers write. "First, adolescents are in a prime developmental phase for the improvement of impulse control. Allowing us the longitudinal variability we would need to test our compensatory model. Second, offenders are prone to antisocial acts, by definition, and their rates of recidivism provided a real-world index of 'successful' versus 'unsuccessful' psychopathy phenotypes."

The study found that higher initial psychopathy was associated with steeper increases in general inhibitory control and the inhibition of aggression over time. That effect was magnified among "successful" offenders, or those who reoffended less.

Its findings lend support to the compensatory model of "successful" psychopathy, Lasko said.

"Our findings support a novel model of psychopathy that we propose, which runs contradictory to the other existing models of psychopathy in that it focuses more on the strengths or 'surpluses' associated with psychopathy rather than just deficits," she said. "Psychopathy is not a personality trait simply composed of deficits -- there are many forms that it can take."

Lasko is a researcher in VCU's Social Psychology and Neuroscience Lab, which seeks to understand why people try to harm one another. David Chester, Ph.D., director of the lab and an assistant professor of psychology, is co-author of the study.

The study's findings could be useful in clinical and forensic settings, Lasko said, particularly for developing effective prevention and early intervention strategies in that it could help identify strengths that psychopathic individuals possess that could deter future antisocial behavior.

Study charts developmental map of inner ear sound sensor in mice

A team of researchers has generated a developmental map of a key sound-sensing structure in the mouse inner ear. Scientists at the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National Institutes of Health, and their collaborators analyzed data from 30,000 cells from mouse cochlea, the snail-shaped structure of the inner ear. The results provide insights into the genetic programs that drive the formation of cells important for detecting sounds. The study also sheds light specifically on the underlying cause of hearing loss linked to Ehlers-Danlos syndrome and Loeys-Dietz syndrome.

The study data is shared on a unique platform open to any researcher, creating an unprecedented resource that could catalyze future research on hearing loss. Led by Matthew W. Kelley, Ph.D., chief of the Section on Developmental Neuroscience at the NIDCD, the study appeared online in Nature Communications. The research team includes investigators at the University of Maryland School of Medicine, Baltimore; Decibel Therapeutics, Boston; and King's College London.

"Unlike many other types of cells in the body, the sensory cells that enable us to hear do not have the capacity to regenerate when they become damaged or diseased," said NIDCD Director Debara L. Tucci, M.D., who is also an otolaryngology-head and neck surgeon. "By clarifying our understanding of how these cells are formed in the developing inner ear, this work is an important asset for scientists working on stem cell-based therapeutics that may treat or reverse some forms of inner ear hearing loss."

In mammals, the primary transducers of sound are hair cells, which are spread across a thin ribbon of tissue (the organ of Corti) that runs the length of the coiled cochlea. There are two kinds of hair cells, inner hair cells and outer hair cells, and they are structurally and functionally sustained by several types of supporting cells. During development, a pool of nearly identical progenitor cells gives rise to these different cell types, but the factors that guide the transformation of progenitors into hair cells are not fully understood.

To learn more about how the cochlea forms, Kelley's team took advantage of a method called single-cell RNA sequencing. This powerful technique enables researchers to analyze the gene activity patterns of single cells. Scientists can learn a lot about a cell from its pattern of active genes because genes encode proteins, which define a cell's function. Cells' gene activity patterns change during development or in response to the environment.

"There are only a few thousand hair cells in the cochlea, and they are arrayed close together in a complex mosaic, an arrangement that makes the cells hard to isolate and characterize," said Kelley. "Single-cell RNA sequencing has provided us with a valuable tool to track individual cells' behaviors as they take their places in the intricate structure of the developing cochlea."

Building on their earlier work on 301 cells, Kelley's team set out to examine the gene activity profiles of 30,000 cells from mouse cochleae collected at four time points, beginning with the 14th day of embryonic development and ending with the seventh postnatal day. Collectively, the data represents a vast catalog of information that researchers can use to explore cochlear development and to study the genes that underlie inherited forms of hearing impairment.

Kelley's team focused on one such gene, Tgfβr1, which has been linked to two conditions associated with hearing loss, Ehlers-Danlos syndrome and Loeys-Dietz syndrome. The data showed that Tgfbr1 is active in outer hair cell precursors as early as the 14th day of embryonic development, suggesting that the gene is important for initiating the formation of these cells.

To explore Tgfβr1's role, the researchers blocked the Tgfbr1 protein's activity in cochleae from 14.5-day-old mouse embryos. When they examined the cochleae five days later, they saw fewer outer hair cells compared to the embryonic mouse cochleae that had not been treated with the Tgfbr1blocker. This finding suggests that hearing loss in people with Tgfβr1 mutations could stem from impaired outer hair cell formation during development.

The study revealed additional insights into the early stages of cochlear development. The developmental pathways of inner and outer hair cells diverge early on; researchers observed distinct gene activity patterns at the earliest time point in the study, the 14th day of embryonic development. This suggests that the precursors from which these cells derive are not as uniform as previously believed. Additional research on cells collected at earlier stages is needed to characterize the initial steps in the formation of hair cells.

In the future, scientists may be able to use the data to steer stem cells toward the hair cell lineage, helping to produce the specialized cells they need to test cell replacement approaches for reversing some forms of hearing loss. The study's results also represent a valuable resource for research on the hearing mechanism and how it goes awry in congenital forms of hearing loss.

The authors have made their data available through the gEAR portal(link is external) (gene Expression Analysis Resource), a web-based platform for sharing, visualizing, and analyzing large multiomic datasets. The portal is maintained by Ronna Hertzano, M.D., Ph.D., and her team in the Department of Otorhinolaryngology and the Institute for Genome Sciences (IGS)(link is external) at the University of Maryland School of Medicine.

"Single-cell RNA sequencing data are highly complex and typically require significant skill to access," said Hertzano. "By disseminating this study data via the gEAR, we are creating an 'encyclopedia' of the genes expressed in the developing inner ear, transforming the knowledge base of our field and making this robust information open and understandable to biologists and other researchers."

Chinese pterodactyl wings its way to the United Kingdom

The first ever specimen of a pterodactyl, more commonly found in China and Brazil, has been found in the United Kingdom.

A fossil hunter recently discovered a peculiar shaped fragment of fossil bone while out walking his dog in Sandown Bay on the Isle of Wight.

Not sure what it was, he passed it to University of Portsmouth Palaeontology student Megan Jacobs, who thought it might be the jaw bone from a pterodactyl. Further research proved she was right.

However, this was no ordinary pterodactyl jaw. This one lacked teeth and was remarkably similar to a bizarre group of pterosaurs called 'tapejarids'. They are better known from China and Brazil and have never previously been found in the UK.

Just last year a team from the University of Portsmouth discovered as similar specimen in North Africa (Morocco) which they named Afrotapejara.

The new specimen from the Isle of Wight has been named Wightia declivirostris.

Megan Jacobs said: "Although only a fragment of jaw, it has all the characteristic of a tapejarid jaw, including numerous tiny little holes that held minute sensory organs for detecting their food, and a downturned, finely pointed beak.

"Complete examples from Brazil and China show that they had large head crests, with the crest sometime being twice as big as the skull. The crests were probably used in sexual display and may have been brightly coloured."

The researchers determined that the Isle of Wight example seemed more closely related to the Chinese tapejarids rather than the Brazilian examples.

Co-author of the study Professor David Martill, a palaeontologist from the University of Portsmouth, said: "This new species adds to the diversity of dinosaurs and other prehistoric reptiles found on the Island, which is now one of the most important places for Cretaceous dinosaurs in the world."

Two bacteria allow spittlebugs to thrive on low-nutrient meals

A new study examines the symbiotic relationship between two types of bacteria and spittlebugs that helps the insect live on very low-nutrient food. The bacteria use a metabolic "trick" also employed by cancer cells to create the right conditions for converting the poor food into the necessary building blocks for survival.

The study, "Syntrophic Splitting of Central Carbon Metabolism in Host Cells Bearing Functionally Different Symbiotic Bacteria," published April 29 in the journal of the International Society for Microbial Ecology.

Spittlebugs get their name from the bubbly spit they create in plant branches. The clusters of spit keeps them from drying out and allow them to hide from predators. There they feed on xylem plant sap, a very low-value food; xylem transports water and minerals from the plant's roots to its leaves.

"No animal should be able to subsist on xylem alone -- it's really just water and a few nutrients," said lead author Nana Ankrah, a postdoctoral researcher in the lab of Angela Douglas, the Daljit S. and Elaine Sarkaria Professor of Insect Physiology and Toxicology in the Department of Entomology in the College of Agriculture and Life Sciences.

The answers to how these bugs survive lie in two types of bacteria that live in separate spittlebug organs, called bacteriomes; one is red, the other orange. Other similar insects that feed on plant sap have just one bacterial partner to help produce high-quality amino acids, the building blocks of proteins.

"We wanted to understand if there were any advantages to having two bacterial symbionts on this very poor diet," Ankrah said.

The researchers collected local spittlebugs, removed their red and orange bacteriomes, incubated the bacteria separately in glucose, and ran metabolic experiments and computer model simulations.

They discovered that the red bacteriome uses a process known as aerobic glycolysis to process glucose, from which the bacteria synthesize seven essential amino acids. Two byproducts of this process, pyruvate and lactate, are assimilated by the orange bacteriome to create ATP molecules, which make energy for cells. The energy boost from ATP allows the bacteria in the orange bacteriome to produce three additional essential amino acids that require a great deal of energy to produce.

Having two bacterial partners instead of one works because they have this method for exchanging products from one bacterium to the other to increase the overall energy available to them, Ankrah said.

The researchers were surprised to find aerobic glycolysis occurring in these bacteria, as cancer cells employ the same process to survive, with a subset of cancer cells undergoing glycolysis and producing pyruvate and lactate, which another subset of cancer cells consumes to create energy.

"To our knowledge," Ankrah said, "our article is the first demonstration of aerobic glycolysis as a strategy to facilitate amino acid production in symbioses."

Future studies will investigate glycolysis in other insect and bacteria partnerships, he said.

How bacteria purge toxic metals

Bacteria have a cunning ability to survive in unfriendly environments.

For example, through a complicated series of interactions, they can identify -- and then build resistance to -- toxic chemicals and metals, such as silver and copper. Bacteria rely on a similar mechanism for defending against antibiotics.

In E. coli bacterium, the inner membrane sensor protein CusS mobilizes from a clustered form upon sensing copper ions in the environment. CusS recruits the transcription regulator protein CusR and then breaks down ATP to phosphorylate CusR, which then proceeds to activate gene expression to help the cell defend against the toxic copper ions.

Cornell researchers combined genetic engineering, single-molecule tracking and protein quantitation to get a closer look at this mechanism and understand how it functions. The knowledge could lead to the development of more effective antibacterial treatments.

The team's paper, "Metal-Induced Sensor Mobilization Turns on Affinity to Activate Regulator for Metal Detoxification in Live Bacteria," published May 28 in Proceedings of the National Academy of Sciences.

"We were really interested in the fundamental mechanism," said Peng Chen, the Peter J.W. Debye Professor of Chemistry in the College of Arts and Sciences and the paper's senior author. "The broader concept is that once we know the mechanism, then perhaps we can come up with better or alternative ways to compromise bacteria's ability in defending against toxic chemicals. That will hopefully contribute to designing new ways of taming bacterial drug resistance."

The bacteria's resistance is actually a tag-team operation, with two proteins working together inside the cell. One protein (CusS), in the inner membrane, senses the presence of the chemical or metal and sends a signal to a regulator protein (CusR) in the cytosol, or intercellular fluid. The regulator protein binds to DNA and activates a gene that generates transport proteins, which purge the toxin from the cell.

Typically, scientists analyze these functions by using biochemical assays that remove the protein from the cell. However, that process prevents the scientists from observing the proteins in their native environment, and certain details, such as the spatial arrangement between proteins, have remained murky.

For a deeper analysis, Chen's team used single-cell imaging, whereby they tagged individual proteins in living E. coli with a fluorescent signal and imaged the proteins one at a time, tracking their motions. The procedure yielded millions of images and, ultimately, a finely detailed, qualitative map of the proteins' movement.

The team was specifically interested in the activities of sensor proteins, which come in two varieties -- those that cluster together and those that move around the inner membrane. The researchers found that when E. coli encounters copper, the free-floating, mobile variety of the sensor proteins increase in number while the clustered faction are reduced. The mobilized sensor proteins interact with the regulator protein and initiate a complex series of steps -- from binding the copper to binding and breaking down the compound ATP, which eventually lead to gene expression -- that will flush the metal from the cell.

"One of the unknowns among the steps is at what point the sensor protein forms a protein-protein complex with the regulator protein," Chen said. "We found that as soon as the sensor binds copper, it already causes its recruitment of this regulator protein. This occurs really, really early in this sequence of events."

The early recruitment provides a functional advantage by initiating the sequence and quickly speeding it along before the sequence has time to decay. Chen likens this strategy to a game of hot potato.

"If I hold a hot potato and want to give it to you, I don't want to hold the potato before calling you over," Chen said. "I want you to be right next to me, so I can immediately pass it to you. Otherwise, the hot potato becomes cold. Or it's too hot, so I have to throw it away. In chemical terms, basically that species would decay or transfer to something else."

Tropical forests can handle the heat, up to a point

Borneo forest

Tropical forests face an uncertain future under climate change, but new research published in Science suggests they can continue to store large amounts of carbon in a warmer world, if countries limit greenhouse gas emissions.

The world's tropical forests store a quarter-century worth of fossil fuel emissions in their trees alone. There are fears that global heating can reduce this store if tree growth reduces or tree death increases, accelerating climate change.

An international research team measured over half a million trees in 813 forests across the tropics to assess how much carbon is stored by forests growing under different climatic conditions today.

The team reveal that tropical forests continue to store high levels of carbon under high temperatures, showing that in the long run these forests can handle heat up to an estimated threshold of 32 degrees Celsius in daytime temperature.

Yet this positive finding is only possible if forests have time to adapt, they remain intact, and if global heating is strictly limited to avoid pushing global temperatures into conditions beyond the critical threshold.

Lead author Dr Martin Sullivan, from the University of Leeds and Manchester Metropolitan University, said: "Our analysis reveals that up to a certain point of heating tropical forests are surprisingly resistant to small temperature differences. If we limit climate change they can continue to store a large amount of carbon in a warmer world.

"The 32 degree threshold highlights the critical importance of urgently cutting our emissions to avoid pushing too many forests beyond the safety zone.

"For example, if we limit global average temperatures to a 2°C increase above pre-industrial levels this pushes nearly three-quarters of tropical forests above the heat threshold we identified. Any further increases in temperature will lead to rapid losses of forest carbon."

Forests release carbon dioxide into the atmosphere when the amount of carbon gained by tree growth is less than that lost through tree mortality and decay.

The study is the first to analyse long-term climate sensitivity based on direct observation of whole forests across the topics. The research suggests that over the long-term, temperature has the greatest effect on forest carbon stocks by reducing growth, with drought killing trees the second key factor.

The researchers conclude that tropical forests have long-term capacity to adapt to some climate change, in part because of their high biodiversity as tree species better able to tolerate new climatic conditions grow well and replace less well-adapted species over the long-term.

But maximizing this potential climate resilience depends on keeping forests intact.

Co-author Professor Beatriz Marimon from the State University of Mato Grosso in Brazil studies some of the world's hottest tropical forests in central Brazil. She noted: "Our results suggest that intact forests are able to withstand some climate change. Yet these heat-tolerant trees also face immediate threats from fire and fragmentation.

"Achieving climate adaptation means first of all protecting and connecting the forests that remain."

Professor Marimon notes the clear limits to adaptation. "The study indicates a heat threshold of 32 degrees Celsius in daytime temperature. Above this point tropical forest carbon declines more quickly with higher temperatures, regardless of which species are present.

"Each degree increase above this 32 degree threshold releases four-times as much carbon dioxide as would have been released below the threshold."

The insights into how the world's tropical forests respond to climate were only possible with decades of careful fieldwork, often in remote locations. The global team of 225 researchers combined forests observations across South America (RAINFOR), Africa (AfriTRON) and Asia (T-FORCES). In each monitoring plot the diameter of each tree and its height was used to calculate how much carbon they stored. Plots were revisited every few years to see how much carbon was being taken in, and how long it was stored before trees died.

To calculate changes in carbon storage required identifying nearly 10,000 tree species and over two million measurements of tree diameter, across 24 tropical countries. According to Professor Simon Lewis of the University of Leeds and University College London: "The amount of carbon absorbed and stored by forests is a crucial element in how the Earth responds to climate change."

"The study underlines why long-term research collaboration is essential for understanding the effects of environmental change. Scientists need to work together more than ever, as monitoring the health of our planet's great tropical forests is vital for all of us."

Cutting carbon emissions enough to keep forests within the safety zone will be very challenging. Study author Professor Oliver Phillips of the University of Leeds said: "Keeping our planet and ourselves healthy has never been more important. Right now, humanity has a unique opportunity to make the transition toward a stable climate.

"By not simply returning to 'business as usual' after the current crisis we can ensure tropical forests remain huge stores of carbon. Protecting them from climate change, deforestation and wildlife exploitation needs to be front and centre of our global push for biosecurity.

"Imagine if we take this chance to reset how we treat our Earth. We can keep our home cool enough to protect these magnificent forests -- and keep all of us safer."

COVID-19 crisis causes 17 percent drop in global carbon emissions

Coronavirus and world concept 

The COVID-19 global lockdown has had an "extreme" effect on daily carbon emissions, but it is unlikely to last -- according to a new analysis by an international team of scientists.

The study published in the journal Nature Climate Change shows that daily emissions decreased by 17% -- or 17 million tonnes of carbon dioxide -- globally during the peak of the confinement measures in early April compared to mean daily levels in 2019, dropping to levels last observed in 2006.

Emissions from surface transport, such as car journeys, account for almost half (43%) of the decrease in global emissions during peak confinement on April 7. Emissions from industry and from power together account for a further 43% of the decrease in daily global emissions.

Aviation is the economic sector most impacted by the lockdown, but it only accounts for 3% of global emissions, or 10% of the decrease in emissions during the pandemic.

The increase in the use of residential buildings from people working at home only marginally offset the drop in emissions from other sectors.

In individual countries, emissions decreased by 26% on average at the peak of their confinement.

The analysis also shows that social responses alone, without increases in wellbeing and/or supporting infrastructure, will not drive the deep and sustained reductions needed to reach net zero emissions.

Prof Corinne Le Quéré of the University of East Anglia, in the UK, led the analysis. She said: "Population confinement has led to drastic changes in energy use and CO2 emissions. These extreme decreases are likely to be temporary though, as they do not reflect structural changes in the economic, transport, or energy systems.

"The extent to which world leaders consider climate change when planning their economic responses post COVID-19 will influence the global CO2 emissions paths for decades to come.

"Opportunities exist to make real, durable, changes and be more resilient to future crises, by implementing economic stimulus packages that also help meet climate targets, especially for mobility, which accounts for half the decrease in emissions during confinement.

"For example in cities and suburbs, supporting walking and cycling, and the uptake of electric bikes, is far cheaper and better for wellbeing and air quality than building roads, and it preserves social distancing."

The team analysed government policies on confinement for 69 countries responsible for 97% of global CO2 emissions. At the peak of the confinement, regions responsible for 89% of global CO2 emissions were under some level of restriction. Data on activities indicative of how much each economic sector was affected by the pandemic was then used to estimate the change in fossil CO2 emissions for each day and country from January to April 2020.

The estimated total change in emissions from the pandemic amounts to 1048 million tonnes of carbon dioxide (MtCO2) until the end of April. Of this, the changes are largest in China where the confinement started, with a decrease of 242 MtCO2, then in the US (207 MtCO2), Europe (123 MtCO2), and India (98 MtCO2). The total change in the UK for January-April 2020 is an estimated 18 MtCO2.

The impact of confinement on 2020 annual emissions is projected to be around 4% to 7% compared to 2019, depending on the duration of the lockdown and the extent of the recovery. If pre-pandemic conditions of mobility and economic activity return by mid-June, the decline would be around 4%. If some restrictions remain worldwide until the end of the year, it would be around 7%.

This annual drop is comparable to the amount of annual emission reductions needed year-on-year across decades to achieve the climate objectives of UN Paris Agreement.

Prof Rob Jackson of Stanford University and Chair of the Global Carbon Project who co-authored the analysis, added: "The drop in emissions is substantial but illustrates the challenge of reaching our Paris climate commitments. We need systemic change through green energy and electric cars, not temporary reductions from enforced behavior."

The authors warn that the rush for economic stimulus packages must not make future emissions higher by delaying New Green Deals or weakening emissions standards.

'Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement', Corinne Le Quéré, Robert B. Jackson, Matthew W. Jones, Adam J. P. Smith, Sam Abernethy, Robbie M. Andrew, Anthony J. De-Gol, David R. Willis, Yuli Shan, Josep G. Canadell, Pierre Friedlingstein, Felix Creutzig, Glen P. Peters, is published in Nature Climate Change on May 19.

Dinosaur-dooming asteroid struck Earth at 'deadliest possible' angle

Dinosaurs and asteroid illustration 

New simulations from Imperial College London have revealed the asteroid that doomed the dinosaurs struck Earth at the 'deadliest possible' angle.

The simulations show that the asteroid hit Earth at an angle of about 60 degrees, which maximised the amount of climate-changing gases thrust into the upper atmosphere.

Such a strike likely unleashed billions of tonnes of sulphur, blocking the sun and triggering the nuclear winter that killed the dinosaurs and 75 per cent of life on Earth 66 million years ago.

Drawn from a combination of 3D numerical impact simulations and geophysical data from the site of the impact, the new models are the first ever fully 3D simulations to reproduce the whole event -- from the initial impact to the moment the final crater, now known as Chicxulub, was formed.

The simulations were performed on the Science and Technology Facilities Council (STFC) DiRAC High Performance Computing Facility.

Lead researcher Professor Gareth Collins, of Imperial's Department of Earth Science and Engineering, said: "For the dinosaurs, the worst-case scenario is exactly what happened. The asteroid strike unleashed an incredible amount of climate-changing gases into the atmosphere, triggering a chain of events that led to the extinction of the dinosaurs. This was likely worsened by the fact that it struck at one of the deadliest possible angles.

"Our simulations provide compelling evidence that the asteroid struck at a steep angle, perhaps 60 degrees above the horizon, and approached its target from the north-east. We know that this was among the worst-case scenarios for the lethality on impact, because it put more hazardous debris into the upper atmosphere and scattered it everywhere -- the very thing that led to a nuclear winter."

The results are published today in Nature Communications.

Crater creation

The upper layers of earth around the Chicxulub crater in present-day Mexico contain high amounts of water as well as porous carbonate and evaporite rocks. When heated and disturbed by the impact, these rocks would have decomposed, flinging vast amounts of carbon dioxide, sulphur and water vapour into the atmosphere.

The sulphur would have been particularly hazardous as it rapidly forms aerosols -- tiny particles that would have blocked the sun's rays, halting photosynthesis in plants and rapidly cooling the climate. This eventually contributed to the mass extinction event that killed 75 per cent of life on Earth.

The team of researchers from Imperial, the University of Freiburg, and The University of Texas at Austin, examined the shape and subsurface structure of the crater using geophysical data to feed into the simulations that helped diagnose the impact angle and direction. Their analysis was also informed by recent results from drilling into the 200 km-wide crater, which brought up rocks containing evidence of the extreme forces generated by the impact.

Peak performance

Pivotal to diagnosing the angle and direction of impact was the relationship between the centre of the crater, the centre of the peak ring -- a ring of mountains made of heavily fractured rock inside the crater rim -- and the centre of dense uplifted mantle rocks, some 30 km beneath the crater.

At Chicxulub, these centres are aligned in a southwest-northeast direction, with the crater centre in between the peak-ring and mantle-uplift centres. The team's 3D Chicxulub crater simulations at an angle of 60 degrees reproduced these observations almost exactly.

The simulations reconstructed the crater formation in unprecedented detail and give us more clues as to how the largest craters on Earth are formed. Previous fully 3D simulations of the Chicxulub impact have covered only the early stages of impact, which include the production of a deep bowl-shaped hole in the crust known as the transient crater and the expulsion of rocks, water and sediment into the atmosphere.

These simulations are the first to continue beyond this intermediate point in the formation of the crater and reproduce the final stage of the crater's formation, in which the transient crater collapses to form the final structure. This allowed the researchers to make the first comparison between 3D Chicxulub crater simulations and the present-day structure of the crater revealed by geophysical data.

Co-author Dr Auriol Rae of the University of Freiburg said: "Despite being buried beneath nearly a kilometre of sedimentary rocks, it is remarkable that geophysical data reveals so much about the crater structure -- enough to describe the direction and angle of the impact."

The researchers say that while the study has given us important insights into the dinosaur-dooming impact, it also helps us understand how large craters on other planets form.

Co-author Dr Thomas Davison, also of Imperial's Department of Earth Science and Engineering, said: "Large craters like Chicxulub are formed in a matter of minutes, and involve a spectacular rebound of rock beneath the crater. Our findings could help advance our understanding of how this rebound can be used to diagnose details of the impacting asteroid."

Rarely heard narwhal vocalizations

Narwhal couple

With the help of Inuit hunters, geophysicists recently recorded the various calls, buzzes, clicks and whistles of narwhals as they summered in a Greenland fjord. The recordings help scientists better understand the soundscape of Arctic glacial fjords and provide valuable insight into the behavior of these shy and mysterious creatures, according to the researchers.

Narwhals are difficult to study because they are notoriously shy and skittish and spend most of their time deep in the freezing Arctic Ocean. They tend to summer in glacial fjords around Greenland and Canada, but scientists often have trouble getting close enough to study them. Glacier fronts can be dangerous and hard to access, and the animals tend to swim off when approached by motorized boats.

But Inuit hunters familiar with the mysterious cetaceans can get closer to the animals without disturbing them. In July 2019, researchers accompanied several Inuit whale hunting expeditions in Northwest Greenland to study the narwhals that summer there in more detail.

Using underwater microphones attached to small boats, the researchers captured narwhal social calls and foraging sounds, getting as close as 25 meters (82 feet) to the elusive cetaceans.

The recordings help the researchers provide a baseline of the kinds of sounds that permeate the narwhals' pristine habitat. In combination with sightings, they also show narwhals get closer to glacier ice than previously thought for this area and the animals do forage for food in summer, contrary to some previous findings.

"Their world is the soundscape of this glacial fjord," said Evgeny Podolskiy, a geophysicist at Hokkaido University in Sapporo, Japan and lead author of a new study detailing the findings in AGU's Journal of Geophysical Research: Oceans. "There are many questions we can answer by listening to glacier fjords in general."

Getting close

Podolskiy and his colleagues had been working in Greenland fjords for several years, studying the sounds made by melting glaciers. Coincidentally, a population of narwhals summers in the fjords they were studying, and Podolskiy saw an opportunity to study the wily creatures.

"I realized working in the area and not paying attention to the elephant in the room -- the key endemic legendary Arctic unicorn just flowing around our glacier -- was a big mistake," he said.

The researchers tagged along on several Inuit hunting expeditions departing from the village of Qaanaaq, placing microphones underwater and recording the baseline sounds of the fjord.

They captured several types of sounds made by narwhals, including social calls, or whistles, and clicks used for echolocation, the biological sonar used by dolphins, bats, some whales and other animals to navigate and find food.

The closer narwhals get to their food, the faster they click, until the noise becomes a buzz not unlike that of a chainsaw. This terminal buzz helps the narwhals pinpoint the location of their prey.

"If you approach and target these fast fish, you better know precisely where they are; you need to gather this information more frequently," Podolskiy said.

Few studies have documented narwhals feeding in the summertime. Because the microphones picked up terminal buzz, a sound associated with finding food, the new study provides further evidence that narwhals do forage in summer.

Surprisingly, the researchers found narwhals come roughly within 1 kilometer (half a mile) of a glacier calving front, despite the fact that these areas are some of the noisiest places in the ocean and calving icebergs can be dangerous.

"There is so much cracking due to ice fracturing and bubbles melting out... it's like a fizzy drink underwater," Podolskiy said. "It seems we are dealing with animals living in one of the most noisy environments without having much trouble with that."

Scientists find brain center that 'profoundly' shuts down pain

Neurons illustration 

A Duke University research team has found a small area of the brain in mice that can profoundly control the animals' sense of pain.

Somewhat unexpectedly, this brain center turns pain off, not on. It's also located in an area where few people would have thought to look for an anti-pain center, the amygdala, which is often considered the home of negative emotions and responses, like the fight or flight response and general anxiety.

"People do believe there is a central place to relieve pain, that's why placebos work," said senior author Fan Wang, the Morris N. Broad Distinguished Professor of neurobiology in the School of Medicine. "The question is where in the brain is the center that can turn off pain."

"Most of the previous studies have focused on which regions are turned ON by pain," Wang said. "But there are so many regions processing pain, you'd have to turn them all off to stop pain. Whereas this one center can turn off the pain by itself."

The work is a follow-up to earlier research in Wang's lab looking at neurons that are activated, rather than suppressed, by general anesthetics. In a 2019 study, they found that general anesthesia promotes slow-wave sleep by activating the supraoptic nucleus of the brain. But sleep and pain are separate, an important clue that led to the new finding, which appears online May 18 in Nature Neuroscience.

The researchers found that general anesthesia also activates a specific subset of inhibitory neurons in the central amygdala, which they have called the CeAga neurons (CeA stands for central amygdala; ga indicates activation by general anesthesia). Mice have a relatively larger central amygdala than humans, but Wang said she had no reason to think we have a different system for controlling pain.

Using technologies that Wang's lab has pioneered to track the paths of activated neurons in mice, the team found the CeAga was connected to many different areas of the brain, "which was a surprise," Wang said.

By giving mice a mild pain stimulus, the researchers could map all of the pain-activated brain regions. They discovered that at least 16 brain centers known to process the sensory or emotional aspects of pain were receiving inhibitory input from the CeAga.

"Pain is a complicated brain response," Wang said. "It involves sensory discrimination, emotion, and autonomic (involuntary nervous system) responses. Treating pain by dampening all of these brain processes in many areas is very difficult to achieve. But activating a key node that naturally sends inhibitory signals to these pain-processing regions would be more robust."

Using a technology called optogenetics, which uses light to activate a small population of cells in the brain, the researchers found they could turn off the self-caring behaviors a mouse exhibits when it feels uncomfortable by activating the CeAga neurons. Paw-licking or face-wiping behaviors were "completely abolished" the moment the light was switched on to activate the anti-pain center.

"It's so drastic," Wang said. "They just instantaneously stop licking and rubbing."

When the scientists dampened the activity of these CeAga neurons, the mice responded as if a temporary insult had become intense or painful again. They also found that low-dose ketamine, an anesthetic drug that allows sensation but blocks pain, activated the CeAga center and wouldn't work without it.

Now the researchers are going to look for drugs that can activate only these cells to suppress pain as potential future pain killers, Wang said.

"The other thing we're trying to do is to (transcriptome) sequence the hell out of these cells," she said. The researchers are hoping to find the gene for a rare or unique cell surface receptor among these specialized cells that would enable a very specific drug to activate these neurons and relieve pain.

Babies know when you imitate them -- and like it

Mother and child

Six-month old infants recognize when adults imitate them, and perceive imitators as more friendly, according to a new study from Lund University in Sweden. The babies looked and smiled longer at an adult who imitated them, as opposed to when the adult responded in other ways. Babies also approached them more, and engaged in imitating games. The research is published in PLOS One.

In the study, a researcher met 6-month old babies in their homes and played with them in four different ways. The researcher either: imitated everything the babies did as a mirror, or as a reverse mirror, imitated only the bodily actions of the babies while keeping an immobile face, or responded with a different action when the babies acted. The latter is called contingent responding and is how most parents would respond to their baby -- when the baby does or needs something, you react accordingly.

The researchers found that the babies looked and smiled longer, and tried to approach the adult more often, during the close mirroring of their actions.

"Imitating young infants seems to be an effective way to catch their interest and bond with them. The mothers were quite surprised to see their infants joyfully engaging in imitation games with a stranger, but also impressed by the infants' behaviours," says Gabriela-Alina Sauciuc, researcher at Lund University and main author of the study.

There was also much testing behavior during imitation. For example, if the baby hit the table and the researcher imitated that action, the baby would then hit the table several times, while carefully watching the researcher's responses. Even when the researcher did not show any emotions at all while imitating, the babies still seemed to recognize that they were being imitated -- and still responded with testing behavior.

"This was quite interesting. When someone actively tests the person who is imitating them, it is usually seen as an indication that the imitated individual is aware that there is a correspondence between their own behaviour and the behaviour of the other," Sauciuc says.

Scientists have long speculated that, through frequent exposure to being imitated, babies learn about cultural norms and interactional routines, or that shared actions are accompanied by shared feelings and intentions. But the empirical evidence to back up such theories is largely missing.

"By showing that 6-month-old infants recognise when they are being imitated, and that imitation has a positive effect on interaction, we begin to fill up this gap. We still have to find out when exactly imitation begins to have such effects, and what role imitation recognition actually plays for babies," Sauciuc concludes.

Increased fertility for women with Neanderthal gene, study suggests

                                                                      DNA abstract illustration

One in three women in Europe inherited the receptor for progesterone from Neandertals -- a gene variant associated with increased fertility, fewer bleedings during early pregnancy and fewer miscarriages. This is according to a study published in Molecular Biology and Evolution by researchers at the Max Planck Institute for Evolutionary Anthropology in Germany and Karolinska Institutet in Sweden.

"The progesterone receptor is an example of how favourable genetic variants that were introduced into modern humans by mixing with Neandertals can have effects in people living today," says Hugo Zeberg, researcher at the Department of Neuroscience at Karolinska Institutet and the Max Planck Institute for Evolutionary Anthropology, who performed the study with colleagues Janet Kelso and Svante Pääbo.

Progesterone is a hormone, which plays an important role in the menstrual cycle and in pregnancy. Analyses of biobank data from more than 450,000 participants -- among them 244,000 women -- show that almost one in three women in Europe have inherited the progesterone receptor from Neandertals. Twenty-nine percent carry one copy of the Neandertal receptor and three percent have two copies.

Favourable effect on fertility

"The proportion of women who inherited this gene is about ten times greater than for most Neandertal gene variants," says Hugo Zeberg. "These findings suggest that the Neandertal variant of the receptor has a favourable effect on fertility."

The study shows that women who carry the Neandertal variant of the receptor tend to have fewer bleedings during early pregnancy, fewer miscarriages, and give birth to more children. Molecular analyses revealed that these women produce more progesterone receptors in their cells, which may lead to increased sensitivity to progesterone and protection against early miscarriages and bleeding.

ESO instrument finds closest black hole to Earth

Black hole illustration

A team of astronomers from the European Southern Observatory (ESO) and other institutes has discovered a black hole lying just 1000 light-years from Earth. The black hole is closer to our Solar System than any other found to date and forms part of a triple system that can be seen with the naked eye. The team found evidence for the invisible object by tracking its two companion stars using the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. They say this system could just be the tip of the iceberg, as many more similar black holes could be found in the future.

"We were totally surprised when we realised that this is the first stellar system with a black hole that can be seen with the unaided eye," says Petr Hadrava, Emeritus Scientist at the Academy of Sciences of the Czech Republic in Prague and co-author of the research. Located in the constellation of Telescopium, the system is so close to us that its stars can be viewed from the southern hemisphere on a dark, clear night without binoculars or a telescope. "This system contains the nearest black hole to Earth that we know of," says ESO scientist Thomas Rivinius, who led the study published today in Astronomy & Astrophysics.

The team originally observed the system, called HR 6819, as part of a study of double-star systems. However, as they analysed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole. The observations with the FEROS spectrograph on the MPG/ESO 2.2-metre telescope at La Silla showed that one of the two visible stars orbits an unseen object every 40 days, while the second star is at a large distance from this inner pair.

Dietrich Baade, Emeritus Astronomer at ESO in Garching and co-author of the study, says: "The observations needed to determine the period of 40 days had to be spread over several months. This was only possible thanks to ESO's pioneering service-observing scheme under which observations are made by ESO staff on behalf of the scientists needing them."

The hidden black hole in HR 6819 is one of the very first stellar-mass black holes found that do not interact violently with their environment and, therefore, appear truly black. But the team could spot its presence and calculate its mass by studying the orbit of the star in the inner pair. "An invisible object with a mass at least 4 times that of the Sun can only be a black hole," concludes Rivinius, who is based in Chile.

Astronomers have spotted only a couple of dozen black holes in our galaxy to date, nearly all of which strongly interact with their environment and make their presence known by releasing powerful X-rays in this interaction. But scientists estimate that, over the Milky Way's lifetime, many more stars collapsed into black holes as they ended their lives. The discovery of a silent, invisible black hole in HR 6819 provides clues about where the many hidden black holes in the Milky Way might be. "There must be hundreds of millions of black holes out there, but we know about only very few. Knowing what to look for should put us in a better position to find them," says Rivinius. Baade adds that finding a black hole in a triple system so close by indicates that we are seeing just "the tip of an exciting iceberg."

Already, astronomers believe their discovery could shine some light on a second system. "We realised that another system, called LB-1, may also be such a triple, though we'd need more observations to say for sure," says Marianne Heida, a postdoctoral fellow at ESO and co-author of the paper. "LB-1 is a bit further away from Earth but still pretty close in astronomical terms, so that means that probably many more of these systems exist. By finding and studying them we can learn a lot about the formation and evolution of those rare stars that begin their lives with more than about 8 times the mass of the Sun and end them in a supernova explosion that leaves behind a black hole."

The discoveries of these triple systems with an inner pair and a distant star could also provide clues about the violent cosmic mergers that release gravitational waves powerful enough to be detected on Earth. Some astronomers believe that the mergers can happen in systems with a similar configuration to HR 6819 or LB-1, but where the inner pair is made up of two black holes or of a black hole and a neutron star. The distant outer object can gravitationally impact the inner pair in such a way that it triggers a merger and the release of gravitational waves. Although HR 6819 and LB-1 have only one black hole and no neutron stars, these systems could help scientists understand how stellar collisions can happen in triple star systems.

Giant meteorite impacts formed parts of the Moon's crust, new evidence shows

                                                                   Moon's south region     
    

                                                                 New research published today in the journal Nature Astronomy reveals a type of destructive event most often associated with disaster movies and dinosaur extinction may have also contributed to the formation of the Moon's surface.

A group of international scientists led by the Royal Ontario Museum has discovered that the formation of ancient rocks on the Moon may be directly linked to large-scale meteorite impacts.

The scientists conducted new research of a unique rock collected by NASA astronauts during the 1972 Apollo 17 mission to the Moon. They found it contains mineralogical evidence that it formed at incredibly high temperatures (in excess of 2300 °C/ 4300 °F) that can only be achieved by the melting of the outer layer of a planet in a large impact event.

In the rock, the researchers discovered the former presence of cubic zirconia, a mineral phase often used as a substitute for diamond in jewellery. The phase would only form in rocks heated to above 2300 °C, and though it has since reverted to a more stable phase (the mineral known as baddeleyite), the crystal retains distinctive evidence of a high-temperature structure. An interactive image of the complex crystal used in the study can be seen here using the Virtual Microscope.

While looking at the structure of the crystal, the researchers also measured the age of the grain, which reveals the baddeleyite formed over 4.3 billion years ago. It was concluded that the high-temperature cubic zirconia phase must have formed before this time, suggesting that large impacts were critically important to forming new rocks on the early Moon.

Fifty years ago, when the first samples were brought back from the surface of the Moon, lunar scientists raised questions about how lunar crustal rocks formed. Even today, a key question remains unanswered: how did the outer and inner layers of the Moon mix after the Moon formed? This new research suggests that large impacts over 4 billion years ago could have driven this mixing, producing the complex range of rocks seen on the surface of the Moon today.

"Rocks on Earth are constantly being recycled, but the Moon doesn't exhibit plate tectonics or volcanism, allowing older rocks to be preserved," explains Dr. Lee White, Hatch Postdoctoral Fellow at the ROM. "By studying the Moon, we can better understand the earliest history of our planet. If large, super-heated impacts were creating rocks on the Moon, the same process was probably happening here on Earth."

"By first looking at this rock, I was amazed by how differently the minerals look compared to other Apollo 17 samples," says Dr. Ana Cernok, Hatch Postdoctoral Fellow at the ROM and co-author of the study. "Although smaller than a millimetre, the baddeleyite grain that caught our attention was the largest one I have ever seen in Apollo samples. This small grain is still holding the evidence for formation of an impact basin that was hundreds of kilometres in diameter. This is significant, because we do not see any evidence of these old impacts on Earth."

Dr. James Darling, a reader at the University of Portsmouth and co-author of the study, says the findings completely change scientists' understanding of the samples collected during the Apollo missions, and, in effect, the geology of the Moon. "These unimaginably violent meteorite impacts helped to build the lunar crust, not only destroy it," he says.

New study estimates the odds of life and intelligence emerging beyond our planet

Alien planet illustration

Humans have been wondering whether we alone in the universe since antiquity.

We know from the geological record that life started relatively quickly, as soon as our planet's environment was stable enough to support it. We also know that the first multicellular organism, which eventually produced today's technological civilization, took far longer to evolve, approximately 4 billion years.

But despite knowing when life first appeared on Earth, scientists still do not understand how life occurred, which has important implications for the likelihood of finding life elsewhere in the universe.

In a new paper published in the Proceeding of the National Academy of Sciences today, David Kipping, an assistant professor in Columbia's Department of Astronomy, shows how an analysis using a statistical technique called Bayesian inference could shed light on how complex extraterrestrial life might evolve in alien worlds.

"The rapid emergence of life and the late evolution of humanity, in the context of the timeline of evolution, are certainly suggestive," Kipping said. "But in this study it's possible to actually quantify what the facts tell us."

To conduct his analysis, Kipping used the chronology of the earliest evidence for life and the evolution of humanity. He asked how often we would expect life and intelligence to re-emerge if Earth's history were to repeat, re-running the clock over and over again.

He framed the problem in terms of four possible answers: Life is common and often develops intelligence, life is rare but often develops intelligence, life is common and rarely develops intelligence and, finally, life is rare and rarely develops intelligence.

This method of Bayesian statistical inference -- used to update the probability for a hypothesis as evidence or information becomes available -- states prior beliefs about the system being modeled, which are then combined with data to cast probabilities of outcomes.

"The technique is akin to betting odds," Kipping said. "It encourages the repeated testing of new evidence against your position, in essence a positive feedback loop of refining your estimates of likelihood of an event."

From these four hypotheses, Kipping used Bayesian mathematical formulas to weigh the models against one another. "In Bayesian inference, prior probability distributions always need to be selected," Kipping said. "But a key result here is that when one compares the rare-life versus common-life scenarios, the common-life scenario is always at least nine times more likely than the rare one."

The analysis is based on evidence that life emerged within 300 million years of the formation of the Earth's oceans as found in carbon-13-depleted zircon deposits, a very fast start in the context of Earth's lifetime. Kipping emphasizes that the ratio is at least 9:1 or higher, depending on the true value of how often intelligence develops.

Kipping's conclusion is that if planets with similar conditions and evolutionary time lines to Earth are common, then the analysis suggests that life should have little problem spontaneously emerging on other planets. And what are the odds that these extraterrestrial lives could be complex, differentiated and intelligent? Here, Kipping's inquiry is less assured, finding just 3:2 odds in favor of intelligent life.

This result stems from humanity's relatively late appearance in Earth's habitable window, suggesting that its development was neither an easy nor ensured process. "If we played Earth's history again, the emergence of intelligence is actually somewhat unlikely," he said.

Kipping points out that the odds in the study aren't overwhelming, being quite close to 50:50, and the findings should be treated as no more than a gentle nudge toward a hypothesis.

"The analysis can't provide certainties or guarantees, only statistical probabilities based on what happened here on Earth," Kipping said. "Yet encouragingly, the case for a universe teeming with life emerges as the favored bet. The search for intelligent life in worlds beyond Earth should be by no means discouraged."