History of temperature changes in the Universe revealed

 How hot is the Universe today? How hot was it before? A new study by an international team of researchers, including members of the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), suggests that the mean temperature of gas in large structures of the Universe has increased about 3 times in the last 8 billion years, to reach about two million Kelvin today.

The large-scale structure of the Universe refers to the global pattern of how galaxies and galaxy clusters are distributed in space. This cosmic net formed from tiny irregularities in the matter distribution in the early Universe, which were amplified through gravitational attraction. "As the Universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies," said Yi-Kuan Chiang, the lead author of the study, and a research fellow at the Ohio State University Center for Cosmology and AstroParticle Physics. "The drag is violent -- so violent that more and more gas is shocked and heated up."

This heated gas can then be used to measure the mean temperature of the Universe over cosmic time. In particular, the researchers used the so-called "Sunyaev-Zeldovich" effect, named after Rashid Sunyaev, director emeritus at the Max Planck Institute for Astrophysics, and Soviet-era physicist Yakov Zeldovich, who first predicted this phenomenon theoretically. This effect arises when low-energy photons of the cosmic microwave background radiation are scattered by hot electrons in the large-scale structure of the Universe. The scattering transfers energy from electrons to photons, making the hot electron gas visible. The intensity of the Sunyaev-Zeldovich effect is proportional to the thermal pressure of the gas, which, in turn, is proportional to the temperature of electrons.

While this measurement is straightforward in principle, collecting the necessary data was a major undertaking. The study, which has been published in the Astrophysical Journal, was done in a collaboration of researchers at the Kavli IPMU, the Ohio State University, the Johns Hopkins University, and the Max Planck Institute for Astrophysics.

The researchers used data collected by two observatories, the Planck satellite and the Sloan Digital Sky Survey (SDSS). Planck is the European Space Agency mission which measured the cosmic microwave background radiation. SDSS collected detailed images and light spectra of galaxies. Combining the two data sets, the scientists were able to measure the amount of thermal pressure around the locations of galaxies and clusters of galaxies.

"It took astronomers more than 15 years to collect the necessary data using a telescope on the ground and one in space," said Brice Ménard who led the analysis with Chiang. Ménard, who has been a visiting scientist at the Kavli IPMU since 2011, added: "On the analysis side, our team spent four years developing the algorithms necessary to extract the signal from these data."

What's more, interpretation of the data required a physical model, which was provided by Ryu Makiya, a research fellow at the Kavli IPMU. "Combining the latest data with a state-of-the-art theoretical model, we were able to reveal how the temperature of the Universe evolved, and how it was linked to formation of the large-scale structure of the Universe," Makiya said. "The next goal is to understand details of the physics of thermal and non-thermal phenomena."

Chiang, from the Ohio Stated University, added: "Our new measurement provides a direct confirmation of the seminal work by Jim Peebles -- the 2019 Nobel Laureate in Physics -- who laid out the theory of the emergence of large-scale structure of the Universe."

The study determined that about eight billion years ago (at a redshift z=1), the mean electron temperature was some 700,000 Kelvin, rising to about two million Kelvin today. Furthermore, the scientists determined that its evolution is almost entirely driven by the growth of structures, as gas is shock heated in collapsing large-scale structures.

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Tree rings may hold clues to impacts of distant supernovas on Earth

 

Tree rings.

Massive explosions of energy happening thousands of light-years from Earth may have left traces in our planet's biology and geology, according to new research by University of Colorado Boulder geoscientist Robert Brakenridge.

The study, published this month in the International Journal of Astrobiology, probes the impacts of supernovas, some of the most violent events in the known universe. In the span of just a few months, a single one of these eruptions can release as much energy as the sun will during its entire lifetime. They're also bright -- really bright.

"We see supernovas in other galaxies all the time," said Brakenridge, a senior research associate at the Institute of Arctic and Alpine Research (INSTAAR) at CU Boulder. "Through a telescope, a galaxy is a little misty spot. Then, all of a sudden, a star appears and may be as bright as the rest of the galaxy."

A very nearby supernova could be capable of wiping human civilization off the face of the Earth. But even from farther away, these explosions may still take a toll, Brakenridge said, bathing our planet in dangerous radiation and damaging its protective ozone layer.

To study those possible impacts, Brakenridge searched through the planet's tree ring records for the fingerprints of these distant, cosmic explosions. His findings suggest that relatively close supernovas could theoretically have triggered at least four disruptions to Earth's climate over the last 40,000 years.

The results are far from conclusive, but they offer tantalizing hints that, when it comes to the stability of life on Earth, what happens in space doesn't always stay in space.

"These are extreme events, and their potential effects seem to match tree ring records," Brakenridge said.

Radiocarbon spikes

His research hinges on the case of a curious atom. Brakenridge explained that carbon-14, also known as radiocarbon, is a carbon isotope that occurs only in tiny amounts on Earth. It's not from around here, either. Radiocarbon is formed when cosmic rays from space bombard our planet's atmosphere on an almost constant basis.

"There's generally a steady amount year after year," Brakenridge said. "Trees pick up carbon dioxide and some of that carbon will be radiocarbon."

Sometimes, however, the amount of radiocarbon that trees pick up isn't steady. Scientists have discovered a handful of cases in which the concentration of this isotope inside tree rings spikes -- suddenly and for no apparent earthly reason. Many scientists have hypothesized that these several-year-long spikes could be due to solar flares or huge ejections of energy from the surface of the sun.

Brakenridge and a handful of other researchers have had their eye on events much farther from home.

"We're seeing terrestrial events that are begging for an explanation," Brakenridge said. "There are really only two possibilities: A solar flare or a supernova. I think the supernova hypothesis has been dismissed too quickly."

Beware Betelgeuse

He noted that scientists have recorded supernovas in other galaxies that have produced a stupendous amount of gamma radiation -- the same kind of radiation that can trigger the formation of radiocarbon atoms on Earth. While these isotopes aren't dangerous on their own, a spike in their levels could indicate that energy from a distant supernova has traveled hundreds to thousands of light-years to our planet.

To test the hypothesis, Brakenridge turned to the past. He assembled a list of supernovas that occurred relatively close to Earth over the last 40,000 years. Scientists can study these events by observing the nebulas they left behind. He then compared the estimated ages of those galactic fireworks to the tree ring record on the ground.

He found that of the eight closest supernovas studied, all seemed to be associated with unexplained spikes in the radiocarbon record on Earth. He considers four of these to be especially promising candidates. Take the case of a former star in the Vela constellation. This celestial body, which once sat about 815 lightyears from Earth, went supernova roughly 13,000 years ago. Not long after that, radiocarbon levels jumped up by nearly 3% on Earth -- a staggering increase.

The findings aren't anywhere close to a smoking gun, or star, in this case. Scientists still have trouble dating past supernovas, making the timing of the Vela explosion uncertain with a possible error of as much as 1,500 years. It's also not clear what the impacts of such a disruption might have been for plants and animals on Earth at the time. But Brakenridge believes that the question is worth a lot more research.

"What keeps me going is when I look at the terrestrial record and I say, 'My God, the predicted and modeled effects do appear to be there.'"

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The universe is getting hot, hot, hot, a new study suggests

 The universe is getting hotter, a new study has found.

The study, published Oct. 13 in the Astrophysical Journal, probed the thermal history of the universe over the last 10 billion years. It found that the mean temperature of gas across the universe has increased more than 10 times over that time period and reached about 2 million degrees Kelvin today -- approximately 4 million degrees Fahrenheit.

"Our new measurement provides a direct confirmation of the seminal work by Jim Peebles -- the 2019 Nobel Laureate in Physics -- who laid out the theory of how the large-scale structure forms in the universe," said Yi-Kuan Chiang, lead author of the study and a research fellow at The Ohio State University Center for Cosmology and AstroParticle Physics.

The large-scale structure of the universe refers to the global patterns of galaxies and galaxy clusters on scales beyond individual galaxies. It is formed by the gravitational collapse of dark matter and gas.

"As the universe evolves, gravity pulls dark matter and gas in space together into galaxies and clusters of galaxies," Chiang said. "The drag is violent -- so violent that more and more gas is shocked and heated up."

The findings, Chiang said, showed scientists how to clock the progress of cosmic structure formation by "checking the temperature" of the universe.

The researchers used a new method that allowed them to estimate the temperature of gas farther away from Earth -- which means further back in time -- and compare them to gases closer to Earth and near the present time. Now, he said, researchers have confirmed that the universe is getting hotter over time due to the gravitational collapse of cosmic structure, and the heating will likely continue.

To understand how the temperature of the universe has changed over time, researchers used data on light throughout space collected by two missions, Planck and the Sloan Digital Sky Survey. Planck is the European Space Agency mission that operates with heavy involvement from NASA; Sloan collects detailed images and light spectra from the universe.

They combined data from the two missions and evaluated the distances of the hot gases near and far via measuring redshift, a notion that astrophysicists use to estimate the cosmic age at which distant objects are observed. ("Redshift" gets its name from the way wavelengths of light lengthen. The farther away something is in the universe, the longer its wavelength of light. Scientists who study the cosmos call that lengthening the redshift effect.)

The concept of redshift works because the light we see from objects farther away from Earth is older than the light we see from objects closer to Earth -- the light from distant objects has traveled a longer journey to reach us. That fact, together with a method to estimate temperature from light, allowed the researchers to measure the mean temperature of gases in the early universe -- gases that surround objects farther away -- and compare that mean with the mean temperature of gases closer to Earth -- gases today.

Those gases in the universe today, the researchers found, reach temperatures of about 2 million degrees Kelvin -- approximately 4 million degrees Fahrenheit, around objects closer to Earth. That is about 10 times the temperature of the gases around objects farther away and further back in time.

The universe, Chiang said, is warming because of the natural process of galaxy and structure formation. It is unrelated to the warming on Earth. "These phenomena are happening on very different scales," he said. "They are not at all connected."

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Radioactive elements may be crucial to the habitability of rocky planets

 The amount of long-lived radioactive elements incorporated into a rocky planet as it forms may be a crucial factor in determining its future habitability, according to a new study by an interdisciplinary team of scientists at UC Santa Cruz.

That's because internal heating from the radioactive decay of the heavy elements thorium and uranium drives plate tectonics and may be necessary for the planet to generate a magnetic field. Earth's magnetic field protects the planet from solar winds and cosmic rays.

Convection in Earth's molten metallic core creates an internal dynamo (the "geodynamo") that generates the planet's magnetic field. Earth's supply of radioactive elements provides more than enough internal heating to generate a persistent geodynamo, according to Francis Nimmo, professor of Earth and planetary sciences at UC Santa Cruz and first author of a paper on the new findings, published November 10 in Astrophysical Journal Letters.

"What we realized was that different planets accumulate different amounts of these radioactive elements that ultimately power geological activity and the magnetic field," Nimmo explained. "So we took a model of the Earth and dialed the amount of internal radiogenic heat production up and down to see what happens."

What they found is that if the radiogenic heating is more than the Earth's, the planet can't permanently sustain a dynamo, as Earth has done. That happens because most of the thorium and uranium end up in the mantle, and too much heat in the mantle acts as an insulator, preventing the molten core from losing heat fast enough to generate the convective motions that produce the magnetic field.

With more radiogenic internal heating, the planet also has much more volcanic activity, which could produce frequent mass extinction events. On the other hand, too little radioactive heat results in no volcanism and a geologically "dead" planet.

"Just by changing this one variable, you sweep through these different scenarios, from geologically dead to Earth-like to extremely volcanic without a dynamo," Nimmo said, adding that these findings warrant more detailed studies.

"Now that we see the important implications of varying the amount of radiogenic heating, the simplified model that we used should be checked by more detailed calculations," he said.

A planetary dynamo has been tied to habitability in several ways, according to Natalie Batalha, a professor of astronomy and astrophysics whose Astrobiology Initiative at UC Santa Cruz sparked the interdisciplinary collaboration that led to this paper.

"It has long been speculated that internal heating drives plate tectonics, which creates carbon cycling and geological activity like volcanism, which produces an atmosphere," Batalha explained. "And the ability to retain an atmosphere is related to the magnetic field, which is also driven by internal heating."

Coauthor Joel Primack, a professor emeritus of physics, explained that stellar winds, which are fast-moving flows of material ejected from stars, can steadily erode a planet's atmosphere if it has no magnetic field.

"The lack of a magnetic field is apparently part of the reason, along with its lower gravity, why Mars has a very thin atmosphere," he said. "It used to have a thicker atmosphere, and for a while it had surface water. Without the protection of a magnetic field, much more radiation gets through and the surface of the planet also becomes less habitable."

Primack noted that the heavy elements crucial to radiogenic heating are created during mergers of neutron stars, which are extremely rare events. The creation of these so-called r-process elements during neutron-star mergers has been a focus of research by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics.

"We would expect considerable variability in the amounts of these elements incorporated into stars and planets, because it depends on how close the matter that formed them was to where these rare events occurred in the galaxy," Primack said.

Astronomers can use spectroscopy to measure the abundance of different elements in stars, and the compositions of planets are expected to be similar to those of the stars they orbit. The rare earth element europium, which is readily observed in stellar spectra, is created by the same process that makes the two longest-lived radioactive elements, thorium and uranium, so europium can be used as a tracer to study the variability of those elements in our galaxy's stars and planets.

Astronomers have obtained europium measurements for many stars in our galactic neighborhood. Nimmo was able use those measurements to establish a natural range of inputs to his models of radiogenic heating. The sun's composition is in the middle of that range. According to Primack, many stars have half as much europium compared to magnesium as the sun, and many stars have up to two times more than the sun.

The importance and variability of radiogenic heating opens up many new questions for astrobiologists, Batalha said.

"It's a complex story, because both extremes have implications for habitability. You need enough radiogenic heating to sustain plate tectonics but not so much that you shut down the magnetic dynamo," she said. "Ultimately, we're looking for the most likely abodes of life. The abundance of uranium and thorium appear to be key factors, possibly even another dimension for defining a Goldilocks planet."

Using europium measurements of their stars to identify planetary systems with different amounts of radiogenic elements, astronomers can start looking for differences between the planets in those systems, Nimmo said, especially once the James Webb Space Telescope is deployed. "The James Webb Space Telescope will be a powerful tool for the characterization of exoplanet atmospheres," he said.

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Urban gulls adapt foraging schedule to human activity patterns

 If you've ever seen a seagull snatch a pasty or felt their beady eyes on your sandwich in the park, you'd be right to suspect they know exactly when to strike to increase their chances of getting a human snack.

A new study by the University of Bristol is the most in-depth look to date at the foraging behaviours of urban gulls and how they've adapted to patterns of human activity in a city.

In comparison to natural environments, urban environments are novel for animals on an evolutionary timescale and present a wide array of potential food sources. In urban environments food availability often fluctuates according to patterns of human activity, which can follow a daily or weekly cycle. However, until now, little has been known about how urban animals adapt to these time differences in human food availability.

A team of scientists from Bristol's Faculties of Engineering and Life Sciences used different data to record the behaviour of urban gulls at three different settings in the city: a public park, a school and a waste centre. The study used data from mini GPS tracker backpacks fitted to 12 Lesser Black?backed Gulls, as well as observations of gull numbers at the different sites.

The team found the birds' foraging patterns closely matched the timing of school breaks and the opening and closing times of the waste centre, but that their activity in the park appeared to correspond with the availability of natural food sources.

These findings suggest gulls may have the behavioural flexibility to adapt their foraging behaviour to human time schedules when beneficial, and that this trait helps them to thrive in cities.

Dr Anouk Spelt, lead author of the paper published in Ibis, the International Journal of Avian Science, said:

"Our first day at the school, the students were excited to tell us about the gulls visiting their school at lunch time. Indeed, our data showed that gulls were not only present in high numbers during lunch time to feed on leftovers, but also just before the start of the school and during the first break when students had their snack. Similarly, at the waste centre the gulls were present in higher numbers on weekdays when the centre was open and trucks were unloading food waste.

"Although everybody has experienced or seen gulls stealing food from people in parks, our gulls mainly went to park first thing in the morning and this may be because earthworms and insects are present in higher numbers during these early hours."

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Research identifies 'volume control' in the brain that supports learning and memory

 A "molecular volume knob" regulating electrical signals in the brain helps with learning and memory, according to a Dartmouth study.

The molecular system controls the width of electrical signals that flow across synapses between neurons.

The finding of the control mechanism, and the identification of the molecule that regulates it, could help researchers in their search for ways to manage neurological disorders, including Alzheimer's disease, Parkinson's disease and epilepsy.

The research, published in Proceedings of the National Academy of Sciences, describes the first study of how the shapes of electrical signals contribute to the functioning of synapses.

"The synapses in our brain are highly dynamic and speak in a range of whispers and shouts," said Michael Hoppa, an assistant professor of biological sciences at Dartmouth and the research lead. "This finding puts us on a straighter path toward being able to cure stubborn neurological disorders."

Synapses are tiny contact points that allow neurons in the brain to communicate at different frequencies. The brain converts electrical inputs from the neurons into chemical neurotransmitters that travel across these synaptic spaces.

The amount of neurotransmitter released changes the numbers and patterns of neurons activated within circuits of the brain. That reshaping of synaptic connection strength is how learning happens and how memories are formed.

Two functions support these processes of memory and learning. One, known as facilitation, is a series of increasingly rapid spikes that amplifies the signals that change a synapse's shape. The other, depression, reduces the signals. Together, these two forms of plasticity keep the brain in balance and prevent neurological disorders such as seizures.

"As we age, its critical to be able to maintain strengthened synapses. We need a good balance of plasticity in our brain, but also stabilization of synaptic connections," said Hoppa.

The research focused on the hippocampus, the center of the brain that is responsible for learning and memory.

In the study, the research team found that the electric spikes are delivered as analog signals whose shape impacts the magnitude of chemical neurotransmitter released across the synapses. This mechanism functions similar to a light dimmer with variable settings. Previous research considered the spikes to be delivered as a digital signal, more akin to a light switch that operates only in the "on" and "off" positions.

"The finding that these electric spikes are analog unlocks our understanding of how the brain works to form memory and learning," said In Ha Cho, a postdoctoral fellow at Dartmouth and first author of the study. "The use of analog signals provides an easier pathway to modulate the strength of brain circuits."

Nobel laureate Eric Kandel conducted work on the connection between learning and the change in shapes of electrical signals in marine sea slugs in 1970. The process was not thought to occur in the more complex synapses found in the mammalian brain at the time.

Beyond discovering that the electrical signals which flow across synapses in the brain's hippocampus are analog, the Dartmouth research also identified the molecule that regulates the electrical signals.

The molecule -- known as Kv?1 -- was previously shown to regulate potassium currents, but was not known to have any role in the synapse controlling the shape of electrical signals. These findings help explain why loss of Kv?1 molecules had previously been shown to negatively impact learning, memory and sleep in mice and fruit flies.

The research also reveals the processes that allow the brain to have such high computational power at such low energy. A single, analog electrical impulse can carry multi-bit information, allowing greater control with low frequency signals.

"This helps our understanding of how our brain is able to work at supercomputer levels with much lower rates of electrical impulses and the energy equivalent of a refrigerator light bulb. The more we learn about these levels of control, it helps us learn how our brains are so efficient," said Hoppa.

For decades, researchers have searched for molecular regulators of synaptic plasticity by focusing on the molecular machinery of chemical release. Until now, measurements of the electrical pulses had been difficult to observe due to the small size of the nerve terminals.

The new research finding was enabled by technology developed at Dartmouth to measure voltage and neurotransmitter release with techniques using light to measure electrical signals in synaptic connections between neurons in the brain.

In future work, the team will seek to determine how the discovery relates to changes in brain metabolism that occur during aging and cause common neurological disorders.

According to the research team, the molecular system exists in an area of the brain that is easily targeted by pharmaceuticals and could lend itself to the development of drug therapies.

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Black hole or no black hole: On the outcome of neutron star collisions

 A new study lead by GSI scientists and international colleagues investigates black-hole formation in neutron star mergers. Computer simulations show that the properties of dense nuclear matter play a crucial role, which directly links the astrophysical merger event to heavy-ion collision experiments at GSI and FAIR. These properties will be studied more precisely at the future FAIR facility. The results have now been published in Physical Review Letters. With the award of the 2020 Nobel Prize in Physics for the theoretical description of black holes and for the discovery of a supermassive object at the center of our galaxy the topic currently also receives a lot of attention.

But under which conditions does a black hole actually form? This is the central question of a study lead by the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt within an international collaboration. Using computer simulations, the scientists focus on a particular process to form black holes namely the merging of two neutron stars (simulation movie).

Neutron stars consists of highly compressed dense matter. The mass of one and a half solar masses is squeezed to the size of just a few kilometers. This corresponds to similar or even higher densities than in the inner of atomic nuclei. If two neutron stars merge, the matter is additionally compressed during the collision. This brings the merger remnant on the brink to collapse to a black hole. Black holes are the most compact objects in the universe, even light cannot escape, so these objects cannot be observed directly.

"The critical parameter is the total mass of the neutron stars. If it exceeds a certain threshold the collapse to a black hole is inevitable" summarizes Dr. Andreas Bauswein from the GSI theory department. However, the exact threshold mass depends on the properties of highly dense nuclear matter. In detail these properties of high-density matter are still not completely understood, which is why research labs like GSI collide atomic nuclei -- like a neutron star merger but on a much smaller scale. In fact, the heavy-ion collisions lead to very similar conditions as mergers of neutron stars. Based on theoretical developments and physical heavy-ion experiments, it is possible to compute certain models of neutron star matter, so-call equations of state.

Employing numerous of these equations of state, the new study calculated the threshold mass for black-hole formation. If neutron star matter or nuclear matter, respectively, is easily compressible -- if the equation of state is "soft" -- already the merger a relatively light neutron stars leads to the formation of a black hole. If nuclear matter is "stiffer" and less compressible, the remnant is stabilized against the so-called gravitational collapse and a massive rotating neutron star remnant forms from the collision. Hence, the threshold mass for collapse itself informs about properties of high-density matter. The new study revealed furthermore that the threshold to collapse may even clarify whether during the collision nucleon dissolve into their constituents, the quarks.

"We are very excited about this results because we expect that future observations can reveal the threshold mass" adds Professor Nikolaos Stergioulas of the department of physics of the Aristotle University Thessaloniki in Greece. Just a few years ago a neutron star merger was observed for the first time by measuring gravitational waves from the collision. Telescopes also found the "electromagnetic counterpart" and detected light from the merger event. If a black hole is directly formed during the collision, the optical emission of the merger is pretty dim. Thus, the observational data indicates if a black hole was created. At the same time the gravitational-wave signal carries information about the total mass of the system. The more massive the stars the stronger is the gravitational-wave signal, which thus allows determining the threshold mass.

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Empathy and perspective taking: How social skills are built

 Understanding what other people want, how they feel, and how they see the world is becoming increasingly important in our complex, globalised society. Social skills enable us to make friends and create a network of people who support us. But not everyone finds it easy to interact with other people. One of the main reasons is that two of the most important social skills -- empathy, i.e. being able to empathise with the other person's emotions, and the ability to take a perspective, i.e. being able to gain an information by adopting another person's point of view -- are developed to different degrees.

Researchers have long been trying to find out what helps one to understand others. The more you know about these two social skills, the better you can help people to form social relationships. However, it still not exactly clear what empathy and perspective taking are (the latter is also known as "theory of mind"). Being able to read a person's emotions through their eyes, understand a funny story, or interpret the action of another person -- in everyday life there are always social situations that require these two important abilities. However, they each require a combination of different individual subordinate skills. If it is necessary to interpret looks and facial expressions in one situation, in another it may be necessary to think along with the cultural background of the narrator or to know his or her current needs.

To date, countless studies have been conducted that examine empathy and perspective taking as a whole. However, it has not yet been clarified what constitutes the core of both competencies and where in the brain their bases lie. Philipp Kanske, former MPI CBS research group leader and currently professor at the TU Dresden, together with Matthias Schurz from the Donders Institute in Nijmegen, Netherlands, and an international team of researchers, have now developed a comprehensive explanatory model.

"Both of these abilities are processed in the brain by a 'main network' specialised in empathy or changing perspective, which is activated in every social situation. But, depending on the situation, it also involves additional networks," Kanske explains, referring to the results of the study, which has just been published in the journal Psychological Bulletin. If we read the thoughts and feelings of others, for example, from their eyes, other additional regions are involved than if we deduce them from their actions or from a narrative. "The brain is thus able to react very flexibly to individual requirements."

For empathy, a main network that can recognise acutely significant situations, for example, by processing fear, works together with additional specialised regions, for example, for face or speech recognition. When changing perspective, in turn, the regions that are also used for remembering the past or fantasising about the future, i.e., for thoughts that deal with things that cannot be observed at the moment, are active as the core network. Here too, additional brain regions are switched on in each concrete situation.

Through their analyses, the researchers have also found out that particularly complex social problems require a combination of empathy and a change of perspective. People who are particularly competent socially seem to view the other person in both ways -- on the basis of feelings and on the basis of thoughts. In their judgement, they then find the right balance between the two.

"Our analysis also shows, however, that a lack of one of the two social skills can also mean that not this skill as a whole is limited. It may be that only a certain factor is affected, such as understanding facial expressions or speech melody," adds Kanske. A single test is therefore not sufficient to certify a person's lack of social skills. Rather, there must be a series of tests to actually assess them as having little empathy, or as being unable to take the other person's point of view.

Read more at Science Daily

Sweet taste reduces appetite?

 The sweet taste of sugar is very popular worldwide. In Austria and Germany, the yearly intake per person adds up to about 33 and 34 kilograms, respectively. Thus, sugar plays an increasingly role in the nutrition and health of the population, especially with regard to body weight. However, little is known about the molecular (taste) mechanisms of sugar that influence dietary intake, independently of its caloric load.

Taste receptor and satiety regulation

"We therefore investigated the role of sweet taste receptor activation in the regulation of satiety," says Veronika Somoza, deputy head of the Department of Physiological Chemistry at the University of Vienna and director of the Leibniz Institute for Food Systems Biology at the Technical University of Munich.

For this purpose, the scientists conducted a blinded, cross-over intervention study with glucose and sucrose. A total of 27 healthy, male persons, between 18 and 45 years of age, received either a 10 percent glucose or sucrose solution (weight percent) or one of the sugar solutions supplemented with 60 ppm lactisole. Lactisole is a substance that binds to a subunit of the sweet receptor and reduces the perception of sweet taste. Despite different types of sugar, all solutions with or without lactisole had the same energy content.

Two hours after drinking each of the test solutions, the participants were allowed to have as much as breakfast they wanted. Shortly before and during the 120-min waiting period, the researchers took blood samples in regular intervals and measured their body temperature.

Additional 100 kilocalories on average

After the consumption of the lactisole-containing sucrose solution, the test persons had an increased energy intake from breakfast of about 13 percent, about 100 kilocalories more, than after drinking the sucrose solution without lactisole. In addition, the subjects of this group showed lower body temperature and reduced plasma serotonin concentrations. Serotonin is a neurotransmitter and tissue hormone which, among other things, has an appetite-suppressing effect. In contrast, the researchers observed no differences after administration of the lactisole-containing glucose solution and the pure glucose solution.

"This result suggests that sucrose, regardless of its energy content, modulates the regulation of satiety and energy intake via the sweet taste receptor," says Barbara Lieder, head of Christian Doppler Laboratory for Taste Research and also deputy head of the Department of Physiological Chemistry of the Faculty of Chemistry at University of Vienna.

The first study author of the study, Kerstin Schweiger, University of Vienna adds: "We do not know yet why we could not observe the lactisole effect with glucose. However, we suspect it is because glucose and sucrose activate the sweet receptor in different ways. We also assume that mechanisms independent of the sweet receptor play a role."

Read more at Science Daily

Large, delayed outbreaks of endemic diseases possible following COVID-19 controls

 

Illustration, people wearing masks.

Measures to reduce the spread of COVID-19 through non-pharmaceutical interventions (NPIs) such as mask wearing and social distancing are a key tool in combatting the impact of the ongoing coronavirus pandemic. These actions also have greatly reduced incidence of many other diseases, including influenza and respiratory syncytial virus (RSV).

Current reductions in these common respiratory infections, however, may merely postpone the incidence of future outbreaks, according to a study by Princeton University researchers published Nov. 9 in the Proceedings of the National Academy of Sciences.

"Declines in case numbers of several respiratory pathogens have been observed recently in many global locations," said first author Rachel Baker, an associate research scholar at the High Meadows Environmental Institute (HMEI) at Princeton University.

"While this reduction in cases could be interpreted as a positive side effect of COVID-19 prevention, the reality is much more complex," Baker said. "Our results suggest that susceptibility to these other diseases, such as RSV and flu, could increase while NPIs are in place, resulting in large outbreaks when they begin circulating again."

Baker and her co-authors found that NPIs could lead to a future uptick in RSV -- an endemic viral infection in the United States and a leading cause of lower respiratory-tract infections in young infants -- but that the same effect was not as pronounced for influenza.

"Although the detailed trajectory of both RSV and influenza in the coming years will be complex, there are clear and overarching trends that emerge when one focuses on some essential effects of NPIs and seasonality on disease dynamics," said co-author Gabriel Vecchi, Princeton professor of geosciences and the High Meadows Environmental Institute.

The researchers used an epidemiological model based on historic RSV data and observations of the recent decline in RSV cases to examine the possible impact of COVID-19 NPIs on future RSV outbreaks in the United States and Mexico.

They found that even relatively short periods of NPI measures could lead to large future RSV outbreaks. These outbreaks were often delayed following the end of the NPI period, with peak cases projected to occur in many locations in winter 2021-22. "It is very important to prepare for this possible future outbreak risk and to pay attention to the full gamut of infections impacted by COVID-19 NPIs," Baker said.

The authors also considered the implications of COVID-19 NPIs for seasonal influenza outbreaks and found results qualitatively similar to RSV. The dynamics of influenza are much harder to project due to viral evolution, however, which drives uncertainty over future circulating strains and the efficacy of available vaccines.

"For influenza, vaccines could make a big difference," Baker said. "In addition, the impact of NPIs on influenza evolution is unclear but potentially very important."

"The decrease in cases of influenza and RSV -- as well as the possible future increase we project -- is arguably the broadest global impact of NPIs across a variety of human diseases that we've seen," said co-author Bryan Grenfell, the Kathryn Briger and Sarah Fenton Professor of Ecology and Evolutionary Biology and Public Affairs, who is associated faculty in HMEI.

"NPIs could have unintended longer-term impacts on the dynamics of other diseases that are similar to the impact on susceptibility we projected for RSV," he said.

A similar effect of pandemic-related NPIs on other pathogens was observed following the 1918 influenza pandemic. Historic measles data from London show a shift from annual cycles to biennial outbreaks following a period of control measures implemented at that time.

Co-author C. Jessica Metcalf, associate professor of ecology and evolutionary biology and public affairs and an associated faculty member in HMEI, said that directly evaluating the associated risks of NPIs by developing and deploying tools such as serology that would better measure susceptibility is an important public health and policy direction. "The future repercussions of NPIs revealed by this paper hinge on how these measures change the landscape of immunity and susceptibility," Metcalf said.

Additional authors on the paper include Wenchang Yang, an associate research scholar in geosciences, and Sang Woo Park, a Ph.D. candidate in ecology and evolutionary biology.

Many of the authors are affiliated with the Climate Change and Infectious Disease initiative funded by HMEI and the Princeton Institute for International and Regional Studies (PIIRS). The current study built on work by the same team published in December 2019 that examined how climate conditions affect RSV outbreaks in the US and Mexico. Another study by the team, published earlier this year, evaluated the impact of the climate and susceptibility on the trajectory of the COVID-19 pandemic.

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Newly discovered fossil shows small-scale evolutionary changes in an extinct human species

 Males of the extinct human species Paranthropus robustus were thought to be substantially larger than females -- much like the size differences seen in modern-day primates such as gorillas, orangutans and baboons. But a new fossil discovery in South Africa instead suggests that P. robustus evolved rapidly during a turbulent period of local climate change about 2 million years ago, resulting in anatomical changes that previously were attributed to sex.

An international research team including anthropologists at Washington University in St. Louis reported their discovery from the fossil-rich Drimolen cave system northwest of Johannesburg in the journal Nature Ecology & Evolution on Nov. 9.

"This is the type of phenomenon that can be hard to document in the fossil record, especially with respect to early human evolution," said David Strait, professor of biological anthropology in Arts & Sciences at Washington University.

The remarkably well-preserved fossil described in the paper was discovered by a student, Samantha Good, who participated in the Drimolen Cave Field School co-led by Strait.

Researchers already knew that the appearance of P. robustus in South Africa roughly coincided with the disappearance of Australopithecus, a somewhat more primitive early human, and the emergence in the region of early representatives of Homo, the genus to which modern people belong. This transition took place very rapidly, perhaps within only a few tens of thousands of years.

"The working hypothesis has been that climate change created stress in populations of Australopithecus leading eventually to their demise, but that environmental conditions were more favorable for Homo and Paranthropus, who may have dispersed into the region from elsewhere," Strait said. "We now see that environmental conditions were probably stressful for Paranthropus as well, and that they needed to adapt to survive."

The new specimen discovered at Drimolen, identified as DNH 155, is clearly a male but differs in important ways from other P. robustus previously discovered at the nearby site of Swartkrans -- where most of the fossils of this species have been found.

Evolution within a species can be difficult to see in the fossil record. Changes may be subtle, and the fossil record is notoriously incomplete.

Usually, the fossil record reveals larger-scale patterns, such as when species or groups of species either appear in the fossil record or go extinct. So this Drimolen discovery provides a rarely seen window into early human evolution.

The new specimen is larger than a well-studied member of the species previously discovered at Drimolen -- an individual known as DNH 7, and presumed to be female -- but is measurably smaller than presumed males from Swartkrans.

"It now looks as if the difference between the two sites cannot simply be explained as differences between males and females, but rather as population-level differences between the sites," said Jesse Martin, a doctoral student at La Trobe University and the co-first author of the study. "Our recent work has shown that Drimolen predates Swartkrans by about 200,000 years, so we believe that P. robustus evolved over time, with Drimolen representing an early population and Swartkrans representing a later, more anatomically derived population."

"One can use the fossil record to help reconstruct the evolutionary relationships between species, and that pattern can provide all sorts of insights into the processes that shaped the evolution of particular groups," Martin said. "But in the case of P. robustus, we can see discrete samples of the species drawn from the same geographic region but slightly different times exhibiting subtle anatomical differences, and that is consistent with change within a species."

"It's very important to be able to document evolutionary change within a lineage," said Angeline Leece of La Trobe University, the other first author of the study. "It allows us to ask very focused questions about evolutionary processes. For example, we now know that tooth size changes over time in the species, which begs the question of why. There are reasons to believe that environmental changes placed these populations under dietary stress, and that points to future research that will let us test this possibility."

Co-director of the Drimolen project, La Trobe University's Andy Herries said, "Like all other creatures on earth, our ancestors adapted and evolved in accordance with the landscape and environment around them. For the first time in South Africa, we have the dating resolution and morphological evidence that allows us to see such changes in an ancient hominin lineage through a short window of time."

The evidence of rapid but significant climate change during this period in South Africa comes from a variety of sources. Critically, fossils indicate that certain mammals associated with woodland or bushland environments went extinct or became less prevalent -- while other species associated with drier, more open environments appeared locally for the first time.

"P. robustus is remarkable in that it possesses a number of features in its cranium, jaws and teeth indicating that it was adapted to eat a diet consisting of either very hard or very tough foods," Strait said. "We think that these adaptations allowed it to survive on foods that were mechanically difficult to eat as the environment changed to be cooler and drier, leading to changes in local vegetation.

"But the specimens from Drimolen exhibit skeletal features suggesting that their chewing muscles were positioned in such a way as to make them less able to bite and chew with as much force as the later P. robustus population from Swartkrans," he said. "Over the course of 200,000 years, a dry climate likely led to natural selection favoring the evolution of a more efficient and powerful feeding apparatus in the species."

Leece said it was notable that P. robustus appeared at roughly the same time as our direct ancestor Homo erectus, as documented by an infant H. erectus cranium that the team discovered at the same Drimolen site in 2015.

"These two vastly different species, H. erectus with their relatively large brains and small teeth, and P. robustus with their relatively large teeth and small brains, represent divergent evolutionary experiments," Leece said. "While we were the lineage that won out in the end, the fossil record suggests that P. robustus was much more common than H. erectus on the landscape two million years ago."

More broadly, the researchers think that this discovery serves as a cautionary tale for recognizing species in the fossil record.

A large number of fossil human species have been discovered over the past quarter century, and many of these new species designations are based on a small number of fossils from only one or a few sites in small geographic areas and narrow time ranges.

"We think that paleoanthropology needs to be a bit more critical about interpreting variation in anatomy as evidence for the presence of multiple species," Strait said. "Depending on the ages of fossil samples, differences in bony anatomy might represent changes within lineages rather than evidence of multiple species."

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Half-a-billion year old microfossils may yield new knowledge of animal origins

 When and how did the first animals appear? Science has long sought an answer. Uppsala University researchers and colleagues in Denmark have now jointly found, in Greenland, embryo-like microfossils up to 570 million years old, revealing that organisms of this type were dispersed throughout the world. The study is published in Communications Biology.

"We believe this discovery of ours improves our scope for understanding the period in Earth's history when animals first appeared -- and is likely to prompt many interesting discussions," says Sebastian Willman, the study's first author and a palaeontologist at Uppsala University.

The existence of animals on Earth around 540 million years ago (mya) is well substantiated. This was when the event in evolution known as the "Cambrian Explosion" took place. Fossils from a huge number of creatures from the Cambrian period, many of them shelled, exist. The first animals must have evolved earlier still; but there are divergent views in the research community on whether the extant fossils dating back to the Precambrian Era are genuinely classifiable as animals.

The new finds from the Portfjeld Formation in the north of Greenland may help to enhance understanding of the origin of animals. In rocks that are 570-560 mya, scientists from Uppsala University, the University of Copenhagen and the Geological Survey of Denmark and Greenland have found microfossils of what might be eggs and animal embryos. These are so well preserved that individual cells, and even intracellular structures, can be studied. The organisms concerned lived in the shallow coastal seas around Greenland during the Ediacaran period, 635-541 mya. The immense variability of microfossils has convinced the researchers that the complexity of life in that period must have been greater than has hitherto been known.

Similar finds were uncovered in southern China's Doushantuo Formation, which is nearly 600 million years old, over three decades ago. Since then, researchers have been discussing what kinds of life form the microfossils represented, and some think they are eggs and embryos from primeval animals. The Greenland fossils are somewhat younger than, but largely identical to, those from China.

The new discovery means that the researchers can also say that these organisms were spread throughout the world. When they were alive, most continents were spaced out south of the Equator. Greenland lay where the expanse of the Southern Ocean (surrounding Antarctica) is now, and China was roughly at the same latitude as present-day Florida.

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Water may be naturally occurring on all rocky planets

 The emergence of life is a mystery. Nevertheless, researchers agree that water is a precondition for life. The first cell emerged in water and then evolved to form multicellular organism. The oldest known single-cell organism on Earth is about 3.5 billion years old.

So far, so good. But if life emerged in water, where did the water come from?

"There are two hypotheses about the emergence of water. One is that it arrives on planets by accident, when asteroids containing water collide with the planet in question," says Professor Martin Bizzarro from the Centre for Star and Planet Formation at the Faculty of Health and Medical Sciences, University of Copenhagen.

Together with Assistant Professor Zhengbin Deng he has headed a new study that turns the theory about the emergence of water upside down.

"The other hypothesis is that water emerges in connection with the formation of the planet. Our study suggests that this hypothesis is correct, and if that is true, it is extremely exciting, because it means that the presence of water is a bioproduct of the planet formation process," Martin Bizzarro explains.

If Martin Bizzarro and Zhengbin Deng's theory proves correct, life in planetary systems may have had better chances of developing than previously assumed.

The researchers' studies show that there was water on Mars for the first 90 million years of the planet's existence. In astronomical time, this is a long time before water-rich asteroids bombarded the planets of the inner Solar System like Earth and Mars, according to the first hypothesis. And this is very sensational', Martin Bizzarro explains.

"It suggests that water emerged with the formation of Mars. And it tells us that water may be naturally occurring on planets and does not require an external source like water-rich asteroids," he says.

The study is based on analyses of an otherwise modest black meteorite. But the meteorite is 4.45 billion years old and contains invaluable knowledge about the young solar system. Black Beauty, which is the name of the meteorite, originates from the original Martian crust and offers unique insight into events at the time of the formation of the solar system.

"It is a gold mine of information. And extremely valuable," says Martin Bizzarro. After having been discovered in the Moroccan desert, the meteorite was sold for USD 10,000 dollars per gram.

With help from funds, Martin Bizzarro managed to buy just under 50 grams for research purposes back in 2017. With the meteorite in the laboratory they are now able to present signs of the presence of liquid water on Mars at the time of its formation. First, however, they had to crush, dissolve and analyse 15 grams of the expensive rock, Zhengbin Deng explains:

"We have developed a new technique that tells us that Mars in its infancy suffered one or more severe asteroid impacts. The impact, Black Beauty reveals, created kinetic energy that released a lot of oxygen. And the only mechanism that could likely have caused the release of such large amounts of oxygen is the presence of water," Zhengbin Deng says.

Another bone of contention between researchers is how Mars with its cold surface temperature could accommodate liquid water causing the depositions of rivers and lakes visible on the planet today. Liquid water is a precondition for the assembling of organic molecules, which is what happened at least 3.5 billion years ago at the emergence of life on Earth.

The researchers' analysis of Black Beauty shows that the asteroid impact on Mars released a lot of greenhouse gasses into the atmosphere.

According to Zhengbin Deng, 'this means that the CO2-rich atmosphere may have caused temperatures to rise and thus allowed liquid water to exist at the surface of Mars'.

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People who eat chili pepper may live longer?

 Individuals who consume chili pepper may live longer and may have a significantly reduced risk of dying from cardiovascular disease or cancer, according to preliminary research to be presented at the American Heart Association's Scientific Sessions 2020. The meeting will be held virtually, Friday, November 13-Tuesday, November 17, 2020.

Previous studies have found eating chili pepper has an anti-inflammatory, antioxidant, anticancer and blood-glucose regulating effect due to capsaicin, which gives chili pepper its characteristic mild to intense spice when eaten. To analyze the effects of chili pepper on all-cause and cardiovascular disease mortality, researchers screened 4,729 studies from five leading global health databases (Ovid, Cochrane, Medline, Embase and Scopus). Their final analysis includes four large studies that included health outcomes for participants with data on chili pepper consumption.

The health and dietary records of more than 570,000 individuals in the United States, Italy, China and Iran were used to compare the outcomes of those who consumed chili pepper to those who rarely or never ate chili pepper. Compared to individuals who rarely or never ate chili pepper, the analysis found that people who ate chili pepper had:
 

• a 26% relative reduction in cardiovascular mortality;
• a 23% relative reduction in cancer mortality; and
• a 25% relative reduction in all-cause mortality.

"We were surprised to find that in these previously published studies, regular consumption of chili pepper was associated with an overall risk-reduction of all cause, CVD and cancer mortality. It highlights that dietary factors may play an important role in overall health," said senior author Bo Xu, M.D., cardiologist at the Cleveland Clinic's Heart, Vascular & Thoracic Institute in Cleveland, Ohio. "The exact reasons and mechanisms that might explain our findings, though, are currently unknown. Therefore, it is impossible to conclusively say that eating more chili pepper can prolong life and reduce deaths, especially from cardiovascular factors or cancer. More research, especially evidence from randomized controlled studies, is needed to confirm these preliminary findings."

Dr. Xu said that there are several limitations to this type of study. The four studies reviewed included limited specific health data on individuals or other factors that may have influenced the findings. Researcher also noted that the amount and type of chili pepper consumed was variable among the studies, making it difficult to draw conclusions about exactly how much, how often and which type of chili pepper consumption may be associated with health benefits. The researchers are continuing to analyze their data and hope to publish the full paper soon.

From Science Daily

Calories by the clock? Squeezing most of your calories in early doesn't impact weight loss

 Restricting meals to early in the day did not affect weight among overweight adults with prediabetes or diabetes, according to preliminary research to be presented at the American Heart Association's Scientific Sessions 2020. The meeting will be held virtually, Friday, November 13 -- Tuesday, November 17, 2020.

"We have wondered for a long time if when one eats during the day affects the way the body uses and stores energy," said study author Nisa M. Maruthur, M.D., M.H.S., associate professor of medicine, epidemiology and nursing at Johns Hopkins University in Baltimore. "Most prior studies have not controlled the number of calories, so it wasn't clear if people who ate earlier just ate fewer calories. In this study, the only thing we changed was the time of day of eating."

Maruthur and colleagues followed 41 overweight adults in a 12-week study. Most participants (90%) were Black women with prediabetes or diabetes, and average age of 59 years. Twenty-one of the adults followed a time-restricted eating pattern, limiting eating to specific hours of the day and ate 80% of their calories before 1 p.m. The remaining 20 participants ate at usual times during a 12-hour window, consuming half of their daily calories after 5 p.m. for the entire 12 weeks. All participants consumed the same pre-prepared, healthy meals provided for the study. Weight and blood pressure were measured at the beginning of the study; then at 4 weeks, 8 weeks and 12 weeks.

The analysis found that people in both groups lost weight and had decreased blood pressure regardless of when they ate.

"We thought that the time-restricted group would lose more weight," Maruthur said. "Yet that didn't happen. We did not see any difference in weight loss for those who ate most of their calories earlier versus later in the day. We did not see any effects on blood pressure either."

The researchers are now collecting more detailed information on blood pressure recorded over 24 hours, and they will be compiling this information with the results of a study on the effects of time-restricted feeding on blood sugar, insulin and other hormones.

"Together, these findings will help us to more fully understand the effects of time-restricted eating on cardiometabolic health," Maruthur said.

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Ancient crocodiles' family tree reveals unexpected twists and turns

 Scientists probing a prehistoric crocodile group's shadowy past have discovered a timeless truth -- pore over anyone's family tree long enough, and something surprising will emerge.

Despite 300 years of research, and a recent renaissance in the study of their biological make-up, the mysterious, marauding teleosauroids have remained enduringly elusive.

Scientific understanding of this distant cousin of present day long snouted gharials has been hampered by a poor grasp of their evolutionary journey -- until now.

Researchers from the University of Edinburgh have identified one previously unknown species of teleosauroid and seven of its close relatives -- part of a group that dominated Jurassic coastlines 190 to 120 million years ago.

Their analysis offers tantalising glimpses of how teleosauroids adapted to the momentous changes that occurred during the Jurassic period, as the earth's seas experienced many changes in temperature.

"Our study just scratches the surface of teleosauroid evolution," says study lead Dr Michela M. Johnson, of the University's School of GeoSciences. "But the findings are remarkable, raising interesting questions about their behaviour and adaptability.

"These creatures represented some of the most successful prehistoric crocodylomorphs during the Jurassic period and there is so much more to learn about them."

The study reveals that not all teleosauroids were engaged in cut and thrust lifestyles, snapping at other reptiles and fish from the seas and swamps near the coast.

Instead, they were a complex, diverse group that were able to exploit different habitats and seek out a variety of food sources. Their physical make-up is also more diverse than was previously understood, the scientists say.

Previous research had provided insights into the origins and evolution of this fossilised croc's whale-like relatives metriorhynchids, but less was known about teleosauroids.

To address this, the expert team of palaeontologists examined more than 500 fossils from more than 25 institutions around the world.

Cutting edge computer software enabled the team to glean swathes of revealing data regarding their anatomical similarities and differences, by examining the entire skeleton, teeth and bony armor, which indicated whether species were closely related or not.

This information enabled the team to create an up-to-date family tree of the teleosauroids group from which emerged two new large groups, whose anatomy, abundance, habitat, geography and feeding styles differ from one another significantly.

The first group, teleosaurids, were more flexible in terms of their habitat and feeding. The second group known as machimosaurids -- which included the fearsome turtle crushers, Lemmysuchus and Machimosaurus -- were more abundant and widespread.

Names given by the team to seven newly described fossils, found in both teleosaurids and machimosaurids, reflect a curious range of anatomical features -- among them Proexochokefalos, meaning 'large head with big tuberosities' and Plagiophthalmosuchus, the 'side-eyed crocodile'.

There are even hints of their diverse behavioural characteristics and unique locations -- Charitomenosuchus, meaning 'graceful crocodile' and Andrianavoay, the 'noble crocodile' from Madagascar.

Researchers have named the newly discovered species, Indosinosuchus kalasinensis, after the Kalasin Province in Thailand, where the fossil -- now housed in Maha Sarakham University -- was found.

The recognition of I. kalasinensis shows that at least two species were living in similar freshwater habitats during the Late Jurassic -- an impressive feat as teleosauroids, with the exception of Machimosaurus, were becoming rare during this time.

Dr Steve Brusatte, Reader in Vertebrate Palaentology, at the School of Geosciences, University of Edinburgh, said: "The same way family trees of our own ancestors and cousins tell us about our history, this huge new family tree of teleosauroids clarifies their evolution. They were some of the most diverse and important animals in the Jurassic oceans, and would have been familiar sights along the coastlines for tens of millions of years."

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Baby dinosaurs were 'little adults'

 

Plateosaurus illustration.

Long neck, small head and a live weight of several tons -- with this description you could have tracked down the Plateosaurus in Central Europe about 220 million years ago. Paleontologists at the University of Bonn (Germany) have now described for the first time an almost complete skeleton of a juvenile Plateosaurus and discovered that it looked very similar to its parents even at a young age. The fact that Plateosaurus showed a largely fully developed morphology at an early age could have important implications for how the young animals lived and moved around. The young Plateosaurus, nicknamed "Fabian," was discovered in 2015 at the Frick fossil site in Switzerland and is exhibited in the local dinosaur museum.

The study was published in the journal Acta Palaeontologica Polonica.

In order to study the appearance of dinosaurs more closely, researchers today rely on a large number of skeletons in so-called bone beds, which are places where the animals sank into the mud in large numbers during their lifetime. However, juvenile animals had hardly been found in these until now. Researchers described fossils of still juvenile plateosaurs for the first time just a few years ago, but these were already almost as large as the adults. One possible reason: "The smaller individuals probably did not sink into the mud quite as easily and are therefore underrepresented at the bone beds," suspects study leader Prof. Martin Sander of the University of Bonn.

He and his team used comparative anatomy to examine the new skeleton, which was immediately remarkable because of its small size. "Based on the length of the vertebrae, we estimate the total length of the individual to be about 7.5 feet (2.3 meters), with a weight of about 90 to 130 lbs. (40 to 60 kilograms)," explains Darius Nau, who was allowed to examine the find for his bachelor's thesis. For comparison: Adult Plateosaurus specimens reached body lengths of 16 to 33 feet (five to ten meters) and could weigh more than four tons. Because of its small size alone, it was obvious to assume that "Fabian" was a juvenile animal. This assumption was confirmed by the fact that the bone sutures of the spinal column had not yet closed. Background: Similar to skull sutures in human babies, bone sutures only fuse over the course of life.

Young and old resembled each other anatomically and in their body proportions

Researchers found that the young dinosaur resembled its older relatives both in anatomical details, such as the pattern of the laminae on the vertebrae (bony lamellae connecting parts of the vertebrae, which are important anatomical features in many dinosaurs), and in the rough proportions of its body. "The hands and neck of the juveniles may be a little longer, the arm bones a little shorter and slimmer. But overall, the variations are relatively small compared to the variation within the species overall and also compared to other dinosaur species," stresses Nau. The juveniles of the related Mussaurus for instance were still quadrupeds after hatching, but the adults were bipeds.

"The fact that the Plateosaurus juvenile already looked so similar to the adults is all the more remarkable considering that they were ten times heavier," emphasizes paleontologist Dr. Jens Lallensack from the University of Bonn. It is however conceivable that the morphological development differed greatly from animal to animal, depending on the climatic conditions or the availability of food. Such differences are still seen in reptiles today.

The well-known descendants of Plateosaurus, the sauropods, are the subject of a current exhibition at the Zoological Research Museum Alexander Koenig in Bonn. The largest Plateosaurus skeleton ever found can be seen there.

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