Dinosaurs were the first to take the perspectives of others

When someone near you turns their head towards something in the environment, you likely can't help to follow their gaze direction. This reaction is observed in mammals, birds and even reptiles alike. It's an effective way to gather information about what caught the attention of your fellow, which you might otherwise have missed. However, a far more advanced behavior is to follow someone's gaze to a location that is initially obstructed from your view. By repositioning yourself to see what the other person is looking at, you demonstrate an understanding that the other has a different perspective. This ability, known as visual perspective taking develops in children between the ages of one-and-a-half to two years and serves as the foundation for later comprehending referential communication and that others have minds that differ from your own.

Visual perspective taking has, to date, only been found in very few species. Mainly in apes and some monkeys, but also in dogs and crow birds. However, there is limited knowledge regarding the evolutionary origins of this crucial social skill. A team of researchers from Lund University aimed to investigate a potential early emergence of visual perspective taking in dinosaurs. Through a comparison of alligators with the most primitive existing birds, known as palaeognaths, they discovered that visual perspective taking originated in the dinosaur lineage likely 60 million years, or more, prior to its appearance in mammals.

Crocodilians are the closest living relatives to birds. Their neuroanatomy has remained largely unchanged for hundreds of millions of years, and is similar to that of the common ancestor of dinosaurs and crocodilians. Palaeognath birds comprise the ostrich birds, such as emus and rheas, but also the flighted tinamous. Their brains are in large parts comparable to their forebearers, the non- avian paravian dinosaurs, which feature such celebrities as the velociraptors. Comparing these two groups of animals creates a bracket around the extinct lineage of dinosaurs leading up to modern birds.

The study revealed that alligators do not demonstrate visual perspective taking, although they do follow gaze to a visible location. In contrast, all tested bird species exhibited visual perspective taking. Additionally, the birds engaged in a behaviour called "checking back," where the observer looks back into the eyes of the gazer, and re-tracks the gaze, when unable to find anything in the direction of their gaze the first time. This behaviour indicates an expectation that the gaze is referring to a target in the environment. Previously, this has only been observed in humans, apes and monkeys, and ravens.

Palaeognath birds emerged 110 million years ago, predating the two mammal groups endowed with visual perspective taking -- primates and dogs -- with 60 million years. Considering the neuroanatomical similarities between these birds and their non-avian forebearers, it is plausible that the skill originated even earlier in the dinosaur lineage. However, it is less likely to have been present among the earliest dinosaurs, which had more alligator-like brains. Maybe future research will show the ability to be more widespread among mammals than currently known, but even if that would be the case it will most probably still be predated by the dinosaur origin. Nevertheless, it is not surprising that visual perspective taking emerged earlier in the dinosaurs, which include the birds, given their superior vision compared to most mammals, that historically relied on nocturnal adaptations. It was only with the emergence of the primates and certain carnivores that our visual capabilities improved.

This is yet another finding that calls into question the prevailing view that mammals drove the evolution of complex cognition, and that they are the cognitive yardstick to which other animals should be compared. An increasing number of studies show the remarkable neurocognition of the avian dinosaurs, the birds, which might prompt a rethinking of the natural history of cognition.

Comments from the authors:

Senior author, prof. Mathias Osvath: "Early in my career, crow birds earned the nickname "feathered apes," due to numerous research findings that showcased their remarkable cognition. However, I'm beginning to question whether it would be more fitting to consider primates as honorary birds."

First author (then PhD-student), Dr Claudia Zeiträg: "Birds are commonly being overlooked when it comes to their cognitive skills. Our findings show that they do not only have several cognitive skills on par with those of apes, but that their forebearers most likely had these skills long before they evolved in mammals."

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Humanity's earliest recorded kiss occurred in Mesopotamia 4,500 years ago

Recent research has hypothesised that the earliest evidence of human lip kissing originated in a very specific geographical location in South Asia 3,500 years ago, from where it may have spread to other regions, simultaneously accelerating the spread of the herpes simplex virus 1.

But according to Dr Troels Pank Arbøll and Dr Sophie Lund Rasmussen, who in a new article in the journal Science draw on a range of written sources from the earliest Mesopotamian societies, kissing was already a well-established practice 4,500 years ago in the Middle East. And probably much earlier, moving the earliest documentation for kissing back 1,000 years compared to what was previously acknowledged in the scientific community.

"In ancient Mesopotamia, which is the name for the early human cultures that existed between the Euphrates and Tigris rivers in present-day Iraq and Syria, people wrote in cuneiform script on clay tablets. Many thousands of these clay tablets have survived to this day, and they contain clear examples that kissing was considered a part of romantic intimacy in ancient times, just as kissing could be part of friendships and family members' relations," says Dr Troels Pank Arbøll, an expert on the history of medicine in Mesopotamia.

He continues:

"Therefore, kissing should not be regarded as a custom that originated exclusively in any single region and spread from there but rather appears to have been practiced in multiple ancient cultures over several millennia."

Dr Sophie Lund Rasmussen adds:

"In fact, research into bonobos and chimpanzees, the closest living relatives to humans, has shown that both species engage in kissing, which may suggest that the practice of kissing is a fundamental behaviour in humans, explaining why it can be found across cultures."

Kissing as potential transmitter of disease

In addition to its importance for social and sexual behaviour, the practice of kissing may have played an unintentional role in the transmission of microorganisms, potentially causing viruses to spread among humans.

However, the suggestion that the kiss may be regarded as a sudden biological trigger behind the spread of particular pathogens is more doubtful. The spread of the herpes simplex virus 1, which researchers have suggested could have been accelerated by the introduction of the kiss, is a case in point:

"There is a substantial corpus of medical texts from Mesopotamia, some of which mention a disease with symptoms reminiscent of the herpes simplex virus 1," Dr Arbøll remarks.

He adds that the ancient medical texts were influenced by a variety of cultural and religious concepts, and it therefore must be emphasized that they cannot be read at face value.

"It is nevertheless interesting to note some similarities between the disease known as bu?shanu in ancient medical texts from Mesopotamia and the symptoms caused by herpes simplex infections. The bu'shanu disease was located primarily in or around the mouth and throat, and symptoms included vesicles in or around the mouth, which is one of the dominant signs of herpes infection."

"If the practice of kissing was widespread and well-established in a range of ancient societies, the effects of kissing in terms of pathogen transmission must likely have been more or less constant," says Dr Rasmussen.

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Butterflies on the decline

Research shows that the numbers of butterflies in meadows and pastures of Europe are in a continuous decline. A new EU regulation aims to stop this trend.

Grassland butterflies will soon play an even greater role in EU nature conservation legislation. Based on the occurrences and population trends of butterflies, the member states are supposed to document the progress they have made in implementing the planned "Nature Restoration Law." The Butterfly Grassland Indicator, recently calculated for the eighth time by European foundation "Butterfly Conservation Europe," is to be used for this. This analysis, which also includes data and expertise from many volunteers in Germany -- coordinated by experts from the Helmholtz Centre for Environmental Research (UFZ) in Halle -- shows an urgent need for action. This is because the situation of grassland butterflies in Europe has deteriorated considerably since the first calculations in 1990.

The diagnosis sounds worrying: More than 80% of habitats in the EU are currently considered vulnerable. This has negative consequences on their functional capability and thus the services they provide for humans. In order to counter this, the European Commission has proposed a new set of rules. This "Nature Restoration Law" is one of the key elements of the EU Biodiversity Strategy 2030 to be published this May. It defines binding targets for the entire EU for the renaturation of various ecosystems. Two years after the regulation enters into force, member states must submit plans on how they intend to meet these targets. They must also document the success of their measures.

However, the latter is not so easy. So far, there are only a few indicators that can reliably show the state of biodiversity. For most animal and plant groups, there is a lack of comparable data across Europe from which to assess the development of populations. The few exceptions include birds, bats, and butterflies.

"Butterflies in particular are ideal bioindicators," says agricultural ecologist Prof. Dr Josef Settele from the UFZ. This is because these insects occur in a wide range of habitats and react sensitively to environmental changes. With their specific requirements, they are often representative of many other insects. Finally, they are eye-catching, attractive, and popular. It is thus relatively easy to motivate volunteers to take part in scientifically oriented butterfly counts.

Such actions are becoming increasingly popular. For example, in 2005 the UFZ and the Gesellschaft für Schmetterlingsschutz (GfS) launched a citizen science project called "Tagfaltermonitoring Deutschland" (Butterfly Monitoring Germany) in which anyone interested can participate. Since then, butterfly enthusiasts from all over Germany have been walking fixed routes from spring to autumn to record the number of individuals and species they have seen. Similar monitoring programmes now exist in most other European countries. "Around 5,000 volunteers spread all over Europe are now taking part -- all following the same protocol," says Settele.

The data are collected and analysed in the central "European Butterfly Monitoring Scheme" (eBMS) database, managed by UKCEH and mirrored at UFZ and the Dutch "Vlinderstichting." In this way, the population development of individual species can then be tracked. Common trends for the inhabitants of certain habitats can also be identified.

This is precisely the idea behind the Butterfly Grassland Indicator, which is based on the population trends of 17 typical species of meadows and pastures. If the positive and negative trends in these species roughly balance each other out, the indicator remains at the same level. If more species decline than increase in the same period, the value decreases -- and vice versa. Lower values thus indicate greater problems among grassland dwellers.

The latest results of these calculations, which include data from 1990 to 2020, therefore do not bode well. The analysis, which was also co-financed by the EU project SPRING (Strengthening Pollinator Recovery through Indicators and monitoring) coordinated by the UFZ, shows only one winner: In the 27 memberstates of the EU, only the Orange Tip (Anthocharis cardamines) displayed a moderate increase. Three species are stable: the Large Skipper (Ochlodes sylvanus), the Common Copper (Lycaena phlaeas), and the Meadow Brown (Maniola jurtina). Five species -- from the Common Blue (Polyommatus icarus) to the Wall Brown (Lasiommata megera) -- are showing declining populations. "The biggest loser in recent years has been the large blue (Phengaris arion), which for example has disappeared completely in the Netherlands," says Settele. For the remaining species of the 17 grassland inhabitants studied, there is either no clear trend or too little data.

The picture becomes even less favourable if we look not only at the EU but rather at Europe as a whole. Then there are no species on the rise and only three are stable. Six show a moderate and one even a strong decline.

In view of these developments, it is not surprising that the grassland indicator is now at a considerably lower level than before. In the last 10 years alone, the calculated value for the EU has fallen by 32% -- and that for Europe as a whole by as much as 36%. The crisis of the grassland dwellers has apparently already taken hold of the entire continent. This is becoming increasingly more evident the more information is provided by the volunteer butterfly counters from different countries. "The declines are not confined to north-western Europe," says Chris van Swaay of Butterfly Conservation Europe. "However, some species in the South and East are doing much better."

He and his colleagues attribute the dwindling butterfly occurrences mainly to changes in agriculture. In north-western Europe, for example, the over-intensive use of meadows and pastures has a particularly unfavourable effect. The heavy use of fertilisers often also pollutes adjacent protected areas with excessive amounts of nitrogen. In the rest of Europe, the main problem is the complete abandonment of cultivation. That's because grassland butterflies also cope poorly with this.

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South Africa's desert-like interior may have been more inviting to our human ancestors

Lining the Cape of South Africa and its southern coast are long chains of caves that nearly 200,000 years ago were surrounded by a lush landscape and plentiful food.

During a glacial phase that lasted between 195,000 to 123,000 years ago, these caves served as refuge to a group of humans that some researchers think were the only people to survive this ice age, called Marine Isotope Stage Six, or MIS6. And in this coastal region, a lot of archaeological research has taken place. Of less interest to archaeologists has been the interior of South Africa, which was thought to be an uninhabited, inhospitable place during at least two waves of ice ages, MIS3 and 2.

Now, a study has shown that the region might have been more fertile and temperate during these two glacial periods than previously thought, and that the region likely played host to human populations living around a series of paleolakes. The study, led by University of Michigan archaeologist Brian Stewart, provides a more comprehensive timeline of the age and stages of these lakes, and shows human fingerprints across the region. The research, funded by the National Geographic Society, is published in the journal PNAS.

"There's this perennial assumption that human population centers were always along the coast and that the interior, especially the southern interior of the Karoo Desert, were largely depopulated for long stretches of time," Stewart said. "The funny thing is that one just has to go into the interior and walk around and notice that there's archaeology everywhere."

But to flag the region as worthy of archaeological attention, the researchers needed to show that humans could have actually lived there. The research team, an international group including researchers from South Africa, the United Kingdom and France, examined a series of super flat areas of land ringed by higher ground. They showed that these regions, called "pans" in Afrikaans, are ancient lake beds, while the areas of higher elevation that encircle them are erosional landforms and sedimentary deposits left over from their ancient shorelines.

This suggests that these time periods were not as dry in this region as previously thought: there would have needed to have been sustained rainfall and humidity to keep these lakes full. The more temperate climate required to sustain lakes also meant the landscape was also able to sustain both vegetation and animals required to support human populations.

Reconstructing the paleolakes

The researchers used a variety of technologies to date and reconstruct these ancient lakes, shorelines and lake bottom deposits, and to recreate the landscape of the region.

These include radiocarbon dating and a technique called luminescence, which measures the radioactivity of tiny crystals of quartz or feldspar that haven't seen the light of day since they were covered by sediment tens of thousands of years earlier. While buried, electrons from radioactive elements common to all sediments get trapped in these crystal matrices at a constant rate. By measuring how many electrons accumulated in the sample and comparing that to the degree of background radioactivity, the researchers can predict its age.

The researchers used these techniques to date columns of sedimentary lakeshore and lake bottom deposits, called lacustrine deposits, found surrounding and within a series of three pans dotted across a region some 100,000 square miles, about the size of Texas. They also aged the shells of freshwater mollusks found scattered throughout the region and embedded within the sedimentary lake deposits.

An aquatic gastropod, Tomichia ventricosa, found at a pan called Swartkolkvloer, was embedded in a column of lacustrine deposits. Together, the deposits and shells were radiocarbon dated to two time periods: approximately 39-55 thousand years before present, and approximately 31-34 thousand years before present.

At another pan called Grootvloer, the researchers found a freshwater mollusk called Unio caffer, which required "perennial freshwater" and the presence of fish to reproduce. These shells and lacustrine deposits in this pan were dated to between approximately 20-22 thousand years before present.

The researchers were also able to predict the area of land the lakes encompassed, as well as how deep they were, based on the height of the lacustrine deposits ringing their shorelines. For example, they determined that the paleolake at Swartkolkvloer was about 83 miles square and 59 feet deep, while the paleolake at Grootvloer was likely about 17 miles square and 62 feet deep. Another pan called Alexanderfontein, some 300 miles northeast near the town of Kimberley, held a lake about 13.5 miles square and 48 feet deep.

Based on these parameters, the researchers knew the lakes would have required a climate drastically different from the one that exists in South Africa's interior today. Using a hydrological model, they determined that evaporation rates within the region were between 20% and 25% lower than what they are today, while precipitation would have been more than 200% higher at Swartkolkvloer and 88% higher at Alexanderfontein.

"In various parts of the interior, between about 60 to about 12,000 years ago, we can see that there were enduring phases of pretty large bodies of water kicking around what used to be thought of as an arid and inhospitable environment," Stewart said. "This was a period that used to be thought of as notoriously dry and freezing cold in the winter. But we've got this evidence for these large lakes existing during this time period."

The researchers say current day regions that have similar climates and rates of precipitation and evaporation are likely northern Botswana, Zambia and Zimbabwe. Based on this estimation and data found from a contemporaneous site called Equus Cave, the researchers think large grazing and browsing mammals would have thrived in this region.

A complex, prehistoric people

Scattered alongside the lakes are human artifacts such as triangular points, bladelets, weathered ostrich shells and other assemblages. Much of these are from the Middle Stone Age, which ranged from about 280,000 years ago to about 25,000 years ago, and the Later Stone Age, which lasted from 25,000 years ago right up to European contact in the 15th century.

"There's Middle Stone Age archaeology just everywhere," Stewart said. "You can't drive anywhere and open the car door and not step on it. It's astounding how much there is."

Stewart says their findings could also expand the region where archaeologists think humans became more behaviorally complex. Over the past decades, researchers have found evidence that humans living in coastal South Africa started making the leap into complex thought, showing some of the earliest signs of behavioral complexity. It was thought that both climate and nutrient stability -- including the rich omega fatty acids gleaned from seafood -- allowed humans here to become behaviorally modern.

The group's work may challenge this idea by suggesting that favorable conditions for hunter-gatherers were not confined to the coastline but probably characterized many regions as climates changed, including the interior, current-day desert.

"Ours is a basin-wide study with much more macro scale implications. It also involves some of these areas that are just inland of this coastal and mountain belt that's dominated the archaeological narratives for so long," Stewart said. "Just inland of this area is a region that has been, for a long time, portrayed as hostile, and it just simply appears not to have been the case for big chunks of time -- with the caveat that we need information on temperature depressions to understand how humans dealt with that."

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Losing sleep over losing sleep: how watching the clock impacts insomnia, use of sleep aids

Watching the clock while trying to fall asleep exacerbates insomnia and the use of sleep aids, according to research from an Indiana University professor -- and a small change could help people sleep better.

The research, led by Spencer Dawson, clinical assistant professor and associate director of clinical training in the College of Arts and Sciences' Department of Psychological and Brain Sciences, focuses on a sample of nearly 5,000 patients presenting for care at a sleep clinic.

Insomnia affects between 4 and 22% of adults and is associated with long-term health problems including cardiovascular disease, diabetes and depression.

Participants completed questionnaires about the severity of their insomnia, their use of sleep medication and the time they spent monitoring their own behavior while trying to fall asleep. They were also asked to report any psychiatric diagnoses. Researchers conducted mediation analyses to determine how the factors influenced each other.

"We found time monitoring behavior mainly has an effect on sleep medication use because it exacerbates insomnia symptoms," Dawson said. "People are concerned that they're not getting enough sleep, then they start estimating how long it will take them to fall back asleep and when they have to be up. That is not the sort of activity that's helpful in facilitating the ability to fall asleep -- the more stressed out you are, the harder time you're going to have falling asleep."

As the frustration over sleeplessness grows, people are more likely to use sleep aids in an attempt to gain control over their sleep.

The results are published in The Primary Care Companion for CNS Disorders. Additional co-authors are Dr. Barry Krakow, professor of psychiatry and behavioral health in the Mercer University School of Medicine; Patricia Haynes, associate professor in the Mel and Enid Zuckerman School of Public Health at the University of Arizona and Darlynn Rojo-Wissar, a postdoctoral fellow at Alpert Medical School of Brown University.

Dawson said the research indicates a simple behavioral intervention could provide help for those struggling with insomnia. He gives the same advice to every new patient the first time they meet.

"One thing that people could do would be to turn around or cover up their clock, ditch the smart watch, get the phone away so they're simply not checking the time," Dawson said. "There's not any place where watching the clock is particularly helpful."

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Scales or feathers? It all comes down to a few genes

Scales, spines, feathers and hair are examples of vertebrate skin appendages, which constitute a remarkably diverse group of micro-organs. Despite their natural multitude of forms, these appendages share early developmental processes at the embryonic stage. Two researchers from the University of Geneva (UNIGE) have discovered how to permanently transform the scales that normally cover the feet of chickens into feathers, by specifically modifying the expression of certain genes. These results, published in the journal Science Advances, open new perspectives for studying mechanisms that have enabled radical evolutionary transitions in form among species.

The skin of terrestrial vertebrates is adorned with diverse keratinized appendages, such as hair, feathers, and scales. Despite the diversity of forms within and among species, the embryonic development of skin appendages typically begins in a very similar way. Indeed, all of these structures develop from cells that produce a localized thickening on the skin surface and express particular genes. One of these genes, called Sonic hedgehog (Shh), controls a signaling pathway -- a communication system that allows the transmission of messages within and between cells. Shh signalling is involved in the development of diverse structures, including the neural tube, limb buds and skin appendages.

A common ancestor

The laboratory of Michel Milinkovitch, professor in the Department of Genetics and Evolution at the Faculty of Science of the UNIGE, is interested in the physical and biological processes that generate the diversity of skin appendages in vertebrates. In particular, his group has previously demonstrated that hair, feathers and scales are homologous structures inherited from a reptilian common ancestor.

Feathers of the chicken embryo are used by scientists as a model system to understand skin appendage development. While it is known that certain breeds of chickens, such as the 'Brahma' and 'Sablepoot' varieties, exhibit feathered legs and dorsal foot surfaces, the genetic determinism of this trait is not fully understood.

A transient modification for a permanent change

As the signaling pathways responsible for this transformation have not been fully determined, Michel Milinkovitch's group investigated the potential role of the Shh pathway. "We used the classic technique of 'egg candling', in which a powerful torch illuminates blood vessels on the inside of the eggshell. This allowed us to precisely treat chicken embryos with a molecule that specifically activates the Shh pathway, injected directly into the bloodstream,'' explains Rory Cooper, a post-doctoral researcher in Michel Milinkovitch's laboratory and co-author of the study.

The two scientists observed that this single stage-specific treatment is sufficient to trigger the formation of abundant juvenile down-type feathers, in areas that would normally be covered with scales. Remarkably, these experimentally-induced feathers are comparable to those covering the rest of the body, as they are regenerative and are subsequently and autonomously replaced by adult feathers.

After comparison with embryos injected with a 'control' solution (without the active molecule), RNA sequencing analysis showed that the Shh pathway is both immediately and persistently activated following injection of the molecule. This confirms that activation of the Shh pathway underlies the conversion of scales into feathers.

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Joro spiders aren't scary: They're shy

Despite their intimidating appearance, the giant yellow and blue-black spiders spreading across the Southeastern U.S. owe their survival to a surprising trait: They're rather timid.

According to a new study from the University of Georgia, the Joro spider may be the shyest spider ever documented.

"One of the ways that people think this spider could be affecting other species is that it's aggressive and out-competing all the other native spiders," said Andy Davis, lead author of the study and a research scientist in UGA's Odum School of Ecology. "So we wanted to get to know the personality of these spiders and see if they're capable of being that aggressive.

"It turns out they're not."

The researchers compared more than 450 spiders' responses to a brief and harmless disturbance across 10 different species.

While most spiders froze for less than a minute before resuming their normal activities, the Joro spiders remained motionless for more than an hour.

"They basically shut down and wait for the disturbance to go away," Davis said. "Our paper shows that these spiders are really more afraid of you than the reverse."

In fact, Joros are relatively harmless to people and pets. Joros won't bite unless cornered. And even if you did manage to somehow annoy a Joro into biting you, its fangs likely wouldn't be large enough to pierce your skin.

Most spiders begin moving quickly after stress, Joros remain immobile for 60+ minutes

To examine the spiders' reaction to stress, the researchers used a turkey baster to gently blow two rapid puffs of air onto individual spiders. This minor disturbance causes the spiders to "freeze" for a period of time, going absolutely still.

The researchers tested more than 30 garden spiders, banded garden spiders and marbled orb weavers. They also analyzed similar data from previously published, peer-reviewed papers that assessed the response of 389 more spiders, comprising five additional species.

All of those spiders began moving again after an average of about a minute and half of stillness.

The Joros, however, stayed frozen with no body or leg movement for over an hour in most cases.

The only other spider species that exhibited a similarly extended response was the Joro spider's cousin, the golden silk spider. Known as Trichonephila clavipes, the golden silk spider and the Joro spider are from the same genus.

Joros may be invasive, but they're not aggressive

Officially known as Trichonephila clavata, the East Asian Joro spider first arrived in Georgia around 2013. The species is native to Japan, Korea, Taiwan and China, and likely hitched a ride stateside on a shipping container.

The species has since rapidly spread across the state and much of the Southeast. Joro spiders easily number in the millions now. And there's not much we can do to stop them from increasing their range.

Davis' previous research even suggested the invasive arachnids could spread beyond their current habitats and through most of the Eastern Seaboard.

"Most people think 'invasive' and 'aggressive' are synonymous," said Amitesh Anerao, co-author of the study and an undergraduate researcher at the university. "People were freaking out about the Joro spiders at first, but maybe this paper can help calm people down."

Joro spiders built to withstand human activity

Joros are regularly spotted in areas native Georgia spiders don't typically inhabit.

They build their golden webs between powerlines, on top of stoplights and even above the pumps at local gas stations -- none of which are particularly peaceful spots.

The researchers believe the Joro spiders' shyness may help them better endure the barrage of noise, vibrations and visual stimuli they consistently encounter in urban settings. Their prolonged freeze response to being startled could help conserve the Joro spiders' energy.

If you're wondering how something so mild-mannered could spread the way Joro spiders have, you aren't the only one.

"One thing this paper tells me is that the Joros' rapid spread must be because of their incredible reproductive potential," Davis said. "They're simply outbreeding everybody else. It's not because they're displacing native spiders or kicking them out of their own webs."

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Radio signal reveals supernova origin

In the latest issue of the journal Nature, astronomers from Stockholm University reveal the origin of a thermonuclear supernova explosion. Strong emission lines of helium and the first detection of such a supernova in radio waves show that the exploding white dwarf star had a helium-rich companion.

Supernovae of Type Ia are important for astronomers since they are used to measure the expansion of the Universe. However, the origin of these explosions has remained an open question. While it is established that the explosion is that of a compact white dwarf star somehow accreting too much matter from a companion star, the exact process and the nature of the progenitor is not known. The new discovery of supernova SN 2020eyj established that the companion star was a helium star that had lost much of its material just prior to the explosion of the white dwarf.

"Once we saw the signatures of strong interaction with the material from the companion we tried to also detect it in radio emission," explains Erik Kool, post-doc at the Department of Astronomy at Stockholm university and lead author of the paper. "The detection in radio is the first one of a Type Ia supernova -- something astronomers have tried to do for decades."

Supernova 2020eyj was discovered by the Zwicky Transient Facility camera on Palomar mountain, where the Oskar Klein Centre at Stockholm University are members.

"The Nordic Optical telescope on La Palma was fundamental for following up this supernova," says Professor Jesper Sollerman at the Department of Astronomy and co-author of the paper. "As were spectra from the large Keck telescope on Hawai'i that immediately revealed the very unusual helium-dominated material around the exploded star."

"This is clearly a very unusual Type Ia supernova, but still related to the ones we use to measure the expansion of the universe," adds Joel Johansson from the Department of Physics.

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Climate change to push species over abrupt tipping points

Climate change is likely to abruptly push species over tipping points as their geographic ranges reach unforeseen temperatures, finds a new study led by a UCL researcher.

The new Nature Ecology & Evolution study predicts when and where climate change is likely to expose species across the globe to potentially dangerous temperatures.

The research team from UCL, University of Cape Town, University of Connecticut and University at Buffalo analysed data from over 35,000 species of animals (including mammals, amphibians, reptiles, birds, corals, fish, cephalopods and plankton) and seagrasses from every continent and ocean basin, alongside climate projections running up to 2100.

The researchers investigated when areas within each species’ geographical range will cross a threshold of thermal exposure, defined as the first five consecutive years where temperatures consistently exceed the most extreme monthly temperature experienced by a species across its geographic range over recent history (1850-2014).

Once the thermal exposure threshold is crossed, the animal is not necessarily going to die out, but there is no evidence that it is able to survive the higher temperatures – that is, the research projects that for many species there could be an abrupt loss of habitat due to future climate change.

The researchers found a consistent trend that for many animals, the thermal exposure threshold will be crossed for much of their geographic range within the same decade.

Lead author Dr Alex Pigot (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) said: “It is unlikely that climate change will gradually make environments more difficult for animals to survive in. Instead, for many animals, large swaths of their geographic range are likely to become unfamiliarly hot in a short span of time.

“While some animals may be able to survive these higher temperatures, many other animals will need to move to cooler regions or evolve to adapt, which they likely cannot do in such short timeframes.

“Our findings suggest that once we start to notice that a species is suffering under unfamiliar conditions, there may be very little time before most of its range becomes inhospitable, so it’s important that we identify in advance which species may be at risk in coming decades.”

The researchers found that the extent of global warming makes a big difference: if the planet warms by 1.5°C, 15% of species they studied will be at risk of experiencing unfamiliarly hot temperatures across at least 30% of their existing geographic range in a single decade, but this doubles to 30% of species at 2.5°C of warming.

Dr Pigot added: “Our study is yet another example of why we need to urgently reduce carbon emissions to mitigate the harmful effects climate change is having on animals and plants, and avoid a massive extinction crisis.”

The researchers hope that their study could help with targeting conservation efforts, as their data provides an early warning system showing when and where particular animals are likely to be at risk.

Co-author Dr Christopher Trisos (African Climate and Development Initiative, University of Cape Town) said: “In the past we’ve had snapshots to show the impact of climate change, but here we are presenting the data more like a film, where you can see the changes unfold over time. This shows that for many species the risk is a bit like everything, everywhere, all at once. By animating this process, we hope to help direct conservation efforts before it’s too late, while also showing the potentially catastrophic consequences of letting climate change continue unchecked.”

The researchers say that this pattern of abrupt exposure may be an inevitable feature of living on a round planet – because of the shape of the Earth, there is more area available to species in environments near the hot end of what they are used to, such as in low-lying areas or near the equator.

A previous study by the same lead authors found that even if we stop climate change so that global temperatures peak and start to decline, the risks to biodiversity could persist for decades after. In another analysis similar to the current study, they found that many species facing unfamiliar temperatures will be living alongside other animals experiencing similar temperature shocks, which could pose grave risks to local ecosystem function.

Read more at Science Daily

Perfection: The Enemy of Evolution

Scientists are often trained to seek out the absolute best solution to a given problem. On a chalk board, this might look something like drawing a graph to find a function's minimum or maximum point. When designing a turbojet engine, it might mean tweaking the rotor blades' angles a tiny degree to achieve a tenth of a percent increase in efficiency.

Adrian Bejan, the J.A. Jones Distinguished Professor of Mechanical Engineering at Duke University, was busy demonstrating the former for a class full of students when a thought struck him: this is not how nature operates. Evolution is a sequence of design changes happening on their own in a discernible direction; it never weds itself to a single point on a drawing board. An evolving system or animal is free to simply go with what works. Not so much that its performance suffers greatly, but enough that it opens access to other options near the so-called optimal design.

With science often looking to nature for clues to solve challenges, Bejan wondered if he might look the opposite way, to predict nature before looking at it. If problem solvers and builders were free to miss the absolute highest mark, how much greater might be the range of designs they consider plausible?

That's the question that Bejan posits in a new paper published online May 16 in the journal Biosystems. Using two relatively simple examples -- walkways ferrying passengers off a train and a bird flapping its wings -- he discovers that the answer is, "quite a lot."

"In engineering, design, theater, architecture or even the organization of this university, any form of design benefits from the ability to make good but imperfect decisions and the freedom to move on and contemplate other opportunities for improvement," Bejan said. "If one is wedded to the idea of the absolute best, nothing new will ever be created."

In the paper, Bejan first looks at the example of passengers arriving by train and walking across a room with many exit points. With the total area of the room remaining constant but the length and width of the room free to change, he solves for the optimal shape of the room to get all passengers where they're going the quickest. With the solution equations in hand, he shows that providing even 1% wiggle room for imperfection away from the best performance opens the design space by 28%.

In his second example, Bejan looks at the flapping motion of birds at nearly constant altitude and speed. Considering the various forces involved -- drag during gliding, lift created by wing size, speed and body size, among others -- he formulates an equation for the rhythm of wings needed to maintain constant speed with minimum effort. While an optimal answer does exist, Bejan once again shows that allowing for just 1% imperfection above the theoretical minimum effort opens the design space by 20%.

Bejan says that he chose these examples because they involved changing only a single variable, a single degree of freedom -- the shape for a room or the flapping rhythm for a wing. In more complex examples that involve many variables, these tiny tolerances for imperfection create an even wider range of "good enough" solutions.

The lesson learned is that science now has a predictive idea of how nature works. By focusing less on finding absolute optimal designs, researchers may use the freedom to iteratively move toward entirely new design concepts that wouldn't otherwise have been within their sight. It also gives designs, methods and entire fields of study the ability to adapt to a changing world.

Read more at Science Daily