Analysis of particles of the asteroid Ryugu delivers surprising results

In December 2020, a small landing capsule brought rock particles from the asteroid Ryugu to Earth -- material from the beginnings of our solar system. The Japanese space probe Hayabusa 2 had collected the samples. Geoscientist Professor Frank Brenker and his team from Goethe University Frankfurt were among the first researchers wordwide allowed literally to "shed light" on these scientifically precious samples. In the process, they discovered areas with a massive accumulation of rare earths and unexpected structures. As part of an international research collaboration, they have now reported on this in the scientific journal Science.

Frank Brenker and his team are world leaders in a method that makes it possible to analyse the chemical composition of material in a three-dimensional and entirely non-destructive way and without complicated sample preparation -- yet with a resolution of under 100 nanometres. Resolution expresses the smallest perceptible difference between two measured values. The method's long name is "Synchrotron Radiation induced X-Ray Fluorescence Computed Tomography," in short SR-XRF-CT.

Japan had chosen Ryugu (English: Dragon's Palace) as the probe's destination because it is an asteroid which, due to its high carbon content, promised to deliver particularly extensive information about the origin of life in our solar system. The analyses conducted on 16 particles by the researchers together with the scientists in Frankfurt have now shown that Ryugu is composed of CI-type material. These are very similar to the Sun in terms of their chemical composition. So far, CI-material has only rarely been found on Earth -- material of which it was unclear how much it had been altered or contaminated when entering Earth's atmosphere or upon impact with our planet. Furthermore, the analysis confirms the assumption that Ryugu originated from a parent asteroid which formed in the outer solar nebula.

Until now, scientists had assumed that there was hardly any transport of material within the asteroid due to the low temperatures during the formation of the CI material in the early days of the solar system and therefore scarcely any possibility for a massive accumulation of elements. By means of SR-XRF-CT, however, the researchers in Frankfurt found a fine vein of magnetite -- an iron oxide mineral -- and hydroxyapatite, a phosphate mineral, in one of the grains of the asteroid. Other groups of scientists established that the structure and other magnetite-hydroxyapatite regions in the Ryugu samples must have formed at a surprisingly low temperature of under 40 °C. This finding is fundamental for interpreting almost all the results that the analysis of the Ryugu samples has generated and will generate in future.

In areas of the samples containing hydroxyapatite, Frank Brenker's team additionally detected rare earth metals -- a group of chemical elements indispensable today for alloys and glassware for high-tech applications, among others. "The rare earths occur in the hydroxyapatite of the asteroid in concentrations 100 times higher than elsewhere in the solar system," says Brenker. What's more, he says, all the elements of the rare earth metals have accumulated in the phosphate mineral to the same degree -- which is also unusual. Brenker is convinced: "This equal distribution of rare earths is a further indication that Ryugu is a very pristine asteroid that represents the beginnings of our solar system."

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Babies react to taste and smell in the womb

Scientists have recorded the first direct evidence that babies react differently to various smells and tastes while in the womb by looking at their facial expressions.

A study led by Durham University's Fetal and Neonatal Research Lab, UK, took 4D ultrasound scans of 100 pregnant women to see how their unborn babies responded after being exposed to flavours from foods eaten by their mothers.

Researchers looked at how the fetuses reacted to either carrot or kale flavours just a short time after the flavours had been ingested by the mothers.

Fetuses exposed to carrot showed more "laughter-face" responses while those exposed to kale showed more "cry-face" responses.

Their findings could further our understanding of the development of human taste and smell receptors.

The researchers also believe that what pregnant women eat might influence babies' taste preferences after birth and potentially have implications for establishing healthy eating habits.

The study is published in the journal Psychological Science.

Humans experience flavour through a combination of taste and smell. In fetuses it is thought that this might happen through inhaling and swallowing the amniotic fluid in the womb.

Lead researcher Beyza Ustun, a postgraduate researcher in the Fetal and Neonatal Research Lab, Department of Psychology, Durham University, said:

"A number of studies have suggested that babies can taste and smell in the womb, but they are based on post-birth outcomes while our study is the first to see these reactions prior to birth.

"As a result, we think that this repeated exposure to flavours before birth could help to establish food preferences post-birth, which could be important when thinking about messaging around healthy eating and the potential for avoiding 'food-fussiness' when weaning.

"It was really amazing to see unborn babies' reaction to kale or carrot flavours during the scans and share those moments with their parents."

The research team, which also included scientists from Aston University, Birmingham, UK, and the National Centre for Scientific Research-University of Burgundy, France, scanned the mothers, aged 18 to 40, at both 32 weeks and 36 weeks of pregnancy to see fetal facial reactions to the kale and carrot flavours.

Mothers were given a single capsule containing approximately 400mg of carrot or 400mg kale powder around 20 minutes before each scan. They were asked not to consume any food or flavoured drinks one hour before their scans.

The mothers also did not eat or drink anything containing carrot or kale on the day of their scans to control for factors that could affect fetal reactions.

Facial reactions seen in both flavour groups, compared with fetuses in a control group who were not exposed to either flavour, showed that exposure to just a small amount of carrot or kale flavour was enough to stimulate a reaction.

Co-author Professor Nadja Reissland, head of the Fetal and Neonatal Research Lab, Department of Psychology, Durham University, supervised Beyza Ustun's research. She said:

"Previous research conducted in my lab has suggested that 4D ultrasound scans are a way of monitoring fetal reactions to understand how they respond to maternal health behaviours such as smoking, and their mental health including stress, depression, and anxiety.

"This latest study could have important implications for understanding the earliest evidence for fetal abilities to sense and discriminate different flavours and smells from the foods ingested by their mothers."

Co-author Professor Benoist Schaal, of the National Centre for Scientific Research-University of Burgundy, France, said:

"Looking at fetuses' facial reactions we can assume that a range of chemical stimuli pass through maternal diet into the fetal environment.

"This could have important implications for our understanding of the development of our taste and smell receptors, and related perception and memory."

The researchers say their findings might also help with information given to mothers about the importance of taste and healthy diets during pregnancy.

They have now begun a follow-up study with the same babies post-birth to see if the influence of flavours they experienced in the womb affects their acceptance of different foods.

Research co-author Professor Jackie Blissett, of Aston University, said:

"It could be argued that repeated prenatal flavour exposures may lead to preferences for those flavours experienced postnatally. In other words, exposing the fetus to less 'liked' flavours, such as kale, might mean they get used to those flavours in utero.

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Why whales don't get brain damage when they swim

Special blood vessels in whale brains may protect them from pulses, caused by swimming, in their blood that would damage the brain, new UBC research has suggested.

There are many theories as to the exact use of these networks of blood vessels cradling a whale's brain and spine, known as 'retia mirabilia', or 'wonderful net', but now UBC zoologists believe they've solved the mystery, with computer modeling backing their predictions.

Land mammals such as horses experience 'pulses' in their blood when galloping, where blood pressures inside the body go up and down on every stride. In a new study, lead author Dr. Margo Lillie and her team have suggested for the first time that the same phenomenon occurs in marine mammals that swim with dorso-ventral movements; in other words, whales. And, they may have found out just why whales avoid long-term damage to the brain for this.

In all mammals, average blood pressure is higher in arteries, or the blood exiting the heart, than in veins. This difference in pressure drives the blood flow in the body, including through the brain, says Dr. Lillie, a research associate emerita in the UBC department of zoology. However, locomotion can forcefully move blood, causing spikes in pressure, or 'pulses' to the brain. The difference in pressure between the blood entering and exiting the brain for these pulses can cause damage.

Long-term damage of this kind can lead to dementia in human beings, says Dr. Lillie. But while horses deal with the pulses by breathing in and out, whales hold their breath when diving and swimming. "So if cetaceans can't use their respiratory system to moderate pressure pulses, they must have found another way to deal with the problem," says Dr. Lillie.

Dr. Lillie and colleagues theorized that the retia use a 'pulse-transfer' mechanism to ensure there is no difference in blood pressure in the cetacean's brain during movement, on top of the average difference. Essentially, rather than dampening the pulses that occur in the blood, the retia transfer the pulse in the arterial blood entering the brain to the venous blood exiting, keeping the same 'amplitude' or strength of pulse, and so, avoiding any difference in pressure in the brain itself.

The researchers collected biomechanic parameters from 11 cetacean species, including, fluking frequency, and input these data into a computer model.

"Our hypothesis that swimming generates internal pressure pulses is new, and our model supports our prediction that locomotion-generated pressure pulses can be synchronized by a pulse transfer mechanism that reduces the pulsatility of resulting flow by up to 97 per cent,"says senior author Dr. Robert Shadwick, professor emeritus in the UBC department of zoology.

The model could potentially be used to ask questions about other animals and what's happening with their blood pressure pulses when they move, including humans, says Dr. Shadwick. And while the researchers say the hypothesis still needs to be tested directly by measuring blood pressures and flow in the brain of swimming cetaceans, this is currently not ethically and technically possible, as it would involve putting a probe in a live whale.

"As interesting as they are, they're essentially inaccessible," he says. "They are the biggest animals on the planet, possibly ever, and understanding how they manage to survive and live and do what they do is a fascinating piece of basic biology."

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Common gene variant linked to COVID mortality

It may be the most baffling quirk of COVID: What manifests as minor, flu-like symptoms in some individuals spirals into severe disease, disability, and even death in others. A new paper published in Nature may explain the genetic underpinnings of this dichotomy.

The researchers demonstrated that mice with gene variants previously linked to Alzheimer's disease were at greater risk of dying when infected with COVID. And a retrospective analysis suggests that patients with those same gene variants were more likely to have died of COVID throughout the pandemic. Because three percent of the world population possesses these gene variants, the findings may have implications for hundreds of millions of individuals globally.

"It is clear that age, sex, and certain preconditions such as diabetes increase the risk of detrimental outcomes, but these factors don't fully explain the spectrum of COVID outcomes," says Sohail Tavazoie, the Leon Hess Professor at The Rockefeller University. "This is the first time that we've seen such a common genetic variant associated with COVID mortality."

A closer look at APOE

In previous work, Tavazoie's lab studied a gene called APOE that plays a role in cancer metastasis. After demonstrating that the gene suppresses the spread of melanoma and regulates anti-tumor immune responses, he and his team began looking at its different forms, or alleles, more closely. Most people have a form called APOE3, but 40 percent of the population carries at least one copy of the APOE2 or APOE4 variant. Individuals with APOE2 or APOE4 produce proteins that differ from APOE3 protein by one or two amino acids.

One or two amino acids make a difference. Individuals with APOE4 are at greater risk of developing Alzheimer's and atherosclerosis, and Tavazoie and Benjamin Ostendorf, a postdoctoral fellow in his lab, have demonstrated that APOE4 and APOE2 impact the immune response against melanoma. As the pandemic progressed, Tavazoie and Ostendorf began to wonder whether APOE variants might impact COVID outcomes, too. "We had looked only at non-infectious diseases," he says. "But what if APOE variants also made people vulnerable to an infectious agent, like SARS-CoV-2? Could they cause different immune responses against a virus?"

To find out, Tavazoie and colleagues first exposed more than 300 mice engineered to carry human APOE to a mouse-adapted version of SARS-CoV-2 produced by colleagues Hans-Heinrich Hoffmann and Charles M. Rice. They found that mice with APOE4 and APOE2 were more likely to die than those with the more common APOE3 allele. "The results were striking," says Ostendorf, lead author on the study. "A difference in just one or two amino acids in the APOE gene was sufficient to cause major differences in the survival of mice exhibiting COVID."

Mice with APOE2 and APOE4 also had more virus replicating in their lungs, and more signs of inflammation and tissue damage. At the cellular level, the researchers found that APOE3 appeared to reduce the amount of virus entering the cell, while animals with the other variants had less potent immune responses to the virus. "Taken together, these results suggest that the APOE genotype impacts COVID outcomes in two ways," Ostendorf says, "by modulating the immune response and by preventing SARS-CoV-2 from infecting cells."

Toward clinical practice

The lab then turned to retrospective human studies. In an analysis of 13,000 patients in the UK Biobank, the researchers found that individuals with two copies of either APOE4 or APOE2 were more likely to have died of COVID than those with two copies of APOE3. (Roughly three percent of individuals have two copies of APOE2 or APOE4, representing an estimated 230 million people worldwide.)

Tavazoie emphasizes that there is no evidence that the 40 percent of individuals carrying only one of these alleles are at increased risk. Moreover, he says those with two APOE2 or APOE4 alleles are likely at lower risk today than the data indicates. "Vaccination changes the picture," he explains. "Data in UK Biobank spans the length of the pandemic, and many of the individuals who died early on would likely have been protected had they been vaccinated."

Moving forward, Tavazoie hopes to see prospective studies on the link between APOE and distinct COVID outcomes. "We've taken the first step," he says. "But to be clinically useful, these results will need to be assessed in prospective human trials that test individuals for their APOE genotypes and account for the availability of vaccination, something that wasn't available early in the pandemic and would improve COVID outcomes across APOE genotypes."

If future studies do confirm a link between APOE and COVID outcomes, clinicians might recommend that individuals with APOE4 or APOE2 be prioritized for vaccinations, boosters, and antiviral therapies. Screening for APOE is fairly routine and inexpensive, and many individuals already know their APOE variants because commercial genetic tests such as 23andMe use it to gauge Alzheimer's risk. At the same time, Tavazoie cautions that screening for a gene variant linked to Alzheimer's is not without ethical hurdles, given that many people would rather not know whether they are predisposed to an incurable neurodegenerative disease.

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Astronomers detect hot gas bubble swirling around the Milky Way's supermassive black hole

Using the Atacama Large Millimeter/submillimeter Array (ALMA), astronomers have spotted signs of a 'hot spot' orbiting Sagittarius A*, the black hole at the centre of our galaxy. The finding helps us better understand the enigmatic and dynamic environment of our supermassive black hole.

"We think we're looking at a hot bubble of gas zipping around Sagittarius A* on an orbit similar in size to that of the planet Mercury, but making a full loop in just around 70 minutes. This requires a mind blowing velocity of about 30% of the speed of light!" says Maciek Wielgus of the Max Planck Institute for Radio Astronomy in Bonn, Germany, who led the study published today in Astronomy & Astrophysics.

The observations were made with ALMA in the Chilean Andes -- a radio telescope co-owned by the European Southern Observatory (ESO) -- during a campaign by the Event Horizon Telescope (EHT) Collaboration to image black holes. In April 2017 the EHT linked together eight existing radio telescopes worldwide, including ALMA, resulting in the recently released first ever image of Sagittarius A*. To calibrate the EHT data, Wielgus and his colleagues, who are members of the EHT Collaboration, used ALMA data recorded simultaneously with the EHT observations of Sagittarius A*. To the team's surprise, there were more clues to the nature of the black hole hidden in the ALMA-only measurements.

By chance, some of the observations were done shortly after a burst or flare of X-ray energy was emitted from the centre of our galaxy, which was spotted by NASA's Chandra Space Telescope. These kinds of flares, previously observed with X-ray and infrared telescopes, are thought to be associated with so-called 'hot spots', hot gas bubbles that orbit very fast and close to the black hole.

"What is really new and interesting is that such flares were so far only clearly present in X-ray and infrared observations of Sagittarius A*. Here we see for the first time a very strong indication that orbiting hot spots are also present in radio observations," says Wielgus, who is also affiliated with the Nicolaus Copernicus Astronomical Centre, Poland and the Black Hole Initiative at Harvard University, USA.

"Perhaps these hot spots detected at infrared wavelengths are a manifestation of the same physical phenomenon: as infrared-emitting hot spots cool down, they become visible at longer wavelengths, like the ones observed by ALMA and the EHT," adds Jesse Vos, a PhD student at Radboud University, the Netherlands, who was also involved in this study.

The flares were long thought to originate from magnetic interactions in the very hot gas orbiting very close to Sagittarius A*, and the new findings support this idea. "Now we find strong evidence for a magnetic origin of these flares and our observations give us a clue about the geometry of the process. The new data are extremely helpful for building a theoretical interpretation of these events," says co-author Monika Mo?cibrodzka from Radboud University.

ALMA allows astronomers to study polarised radio emission from Sagittarius A*, which can be used to unveil the black hole's magnetic field. The team used these observations together with theoretical models to learn more about the formation of the hot spot and the environment it is embedded in, including the magnetic field around Sagittarius A*. Their research provides stronger constraints on the shape of this magnetic field than previous observations, helping astronomers uncover the nature of our black hole and its surroundings.

The observations confirm some of the previous discoveries made by the GRAVITY instrument at ESO's Very Large Telescope (VLT), which observes in the infrared. The data from GRAVITY and ALMA both suggest the flare originates in a clump of gas swirling around the black hole at about 30% of the speed of light in a clockwise direction in the sky, with the orbit of the hot spot being nearly face-on.

"In the future we should be able to track hot spots across frequencies using coordinated multiwavelength observations with both GRAVITY and ALMA -- the success of such an endeavour would be a true milestone for our understanding of the physics of flares in the Galactic centre," says Ivan Marti-Vidal of the University of València in Spain, co-author of the study.

The team is also hoping to be able to directly observe the orbiting gas clumps with the EHT, to probe ever closer to the black hole and learn more about it. "Hopefully, one day, we will be comfortable saying that we 'know' what is going on in Sagittarius A*," Wielgus concludes.

Read more at Science Daily

COVID-19 infections increase risk of long-term brain problems

If you've had COVID-19, it may still be messing with your brain. Those who have been infected with the virus are at increased risk of developing a range of neurological conditions in the first year after the infection, new research shows. Such complications include strokes, cognitive and memory problems, depression, anxiety and migraine headaches, according to a comprehensive analysis of federal health data by researchers at Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care system.

Additionally, the post-COVID brain is associated with movement disorders, from tremors and involuntary muscle contractions to epileptic seizures, hearing and vision abnormalities, and balance and coordination difficulties as well as other symptoms similar to what is experienced with Parkinson's disease.

The findings are published Sept. 22 in Nature Medicine.

"Our study provides a comprehensive assessment of the long-term neurologic consequences of COVID-19," said senior author Ziyad Al-Aly, MD, a clinical epidemiologist at Washington University. "Past studies have examined a narrower set of neurological outcomes, mostly in hospitalized patients. We evaluated 44 brain and other neurologic disorders among both nonhospitalized and hospitalized patients, including those admitted to the intensive care unit. The results show the devastating long-term effects of COVID-19. These are part and parcel of long COVID. The virus is not always as benign as some people think it is."

Overall, COVID-19 has contributed to more than 40 million new cases of neurological disorders worldwide, Al-Aly said.

Other than having a COVID infection, specific risk factors for long-term neurological problems are scarce. "We're seeing brain problems in previously healthy individuals and those who have had mild infections," Al-Aly said. "It doesn't matter if you are young or old, female or male, or what your race is. It doesn't matter if you smoked or not, or if you had other unhealthy habits or conditions."

Few people in the study were vaccinated for COVID-19 because the vaccines were not yet widely available during the time span of the study, from March 2020 through early January 2021. The data also predates delta, omicron and other COVID variants.

A previous study in Nature Medicine led by Al-Aly found that vaccines slightly reduce -- by about 20% -- the risk of long-term brain problems. "It is definitely important to get vaccinated but also important to understand that they do not offer complete protection against these long-term neurologic disorders," Al-Aly said.

The researchers analyzed about 14 million de-identified medical records in a database maintained by the U.S. Department of Veterans Affairs, the nation's largest integrated health-care system. Patients included all ages, races and sexes.

They created a controlled data set of 154,000 people who had tested positive for COVID-19 sometime from March 1, 2020, through Jan. 15, 2021, and who had survived the first 30 days after infection. Statistical modeling was used to compare neurological outcomes in the COVID-19 data set with two other groups of people not infected with the virus: a control group of more than 5.6 million patients who did not have COVID-19 during the same time frame; and a control group of more than 5.8 million people from March 2018 to December 31, 2019, long before the virus infected and killed millions across the globe.

The researchers examined brain health over a year-long period. Neurological conditions occurred in 7% more people with COVID-19 compared with those who had not been infected with the virus. Extrapolating this percentage based on the number of COVID-19 cases in the U.S., that translates to roughly 6.6 million people who have suffered brain impairments associated with the virus.

Memory problems -- colloquially called brain fog -- are one of the most common brain-related, long-COVID symptoms. Compared with those in the control groups, people who contracted the virus were at a 77% increased risk of developing memory problems. "These problems resolve in some people but persist in many others," Al-Aly said. "At this point, the proportion of people who get better versus those with long-lasting problems is unknown."

Interestingly, the researchers noted an increased risk of Alzheimer's disease among those infected with the virus. There were two more cases of Alzheimer's per 1,000 people with COVID-19 compared with the control groups. "It's unlikely that someone who has had COVID-19 will just get Alzheimer's out of the blue," Al-Aly said. "Alzheimer's takes years to manifest. But what we suspect is happening is that people who have a predisposition to Alzheimer's may be pushed over the edge by COVID, meaning they're on a faster track to develop the disease. It's rare but concerning."

Also compared to the control groups, people who had the virus were 50% more likely to suffer from an ischemic stroke, which strikes when a blood clot or other obstruction blocks an artery's ability to supply blood and oxygen to the brain. Ischemic strokes account for the majority of all strokes, and can lead to difficulty speaking, cognitive confusion, vision problems, the loss of feeling on one side of the body, permanent brain damage, paralysis and death.

"There have been several studies by other researchers that have shown, in mice and humans, that SARS-CoV-2 can attack the lining of the blood vessels and then then trigger a stroke or seizure," Al-Aly said. "It helps explain how someone with no risk factors could suddenly have a stroke."

Overall, compared to the uninfected, people who had COVID-19 were 80% more likely to suffer from epilepsy or seizures, 43% more likely to develop mental health disorders such as anxiety or depression, 35% more likely to experience mild to severe headaches, and 42% more likely to encounter movement disorders. The latter includes involuntary muscle contractions, tremors and other Parkinson's-like symptoms.

COVID-19 sufferers were also 30% more likely to have eye problems such as blurred vision, dryness and retinal inflammation; and they were 22% more likely to develop hearing abnormalities such as tinnitus, or ringing in the ears.

"Our study adds to this growing body of evidence by providing a comprehensive account of the neurologic consequences of COVID-19 one year after infection," Al-Aly said.

Read more at Science Daily

Shaking the dinosaur family tree: How did 'bird-hipped' dinosaurs evolve?

Researchers have conducted a new analysis of the origins of 'bird-hipped' dinosaurs -- the group which includes iconic species such as Triceratops -- and found that they likely evolved from a group of animals known as silesaurs, which were first identified two decades ago.

The researchers, from the University of Cambridge and the Universidade Federal de Santa Maria in Brazil, were attempting to solve a long-standing mystery in palaeontology: where the 'bird-hipped' dinosaurs, or ornithischians, came from.

Currently, there is a gap of more than 25 million years in the fossil record, making it difficult to find the branch of the dinosaur family tree where ornithischians belong.

The researchers conducted an extensive analysis of early dinosaurs as well as silesaurs, a group named after Silesaurus, first described in 2003. The researchers suggest that silesaurs progressively modified their anatomy during the Late Triassic Period, so that they came to resemble ornithischians by the Early Jurassic Period.

However, these ornithischian ancestors have the hip structure of the 'lizard-hipped' dinosaurs, or saurischians, suggesting that the earliest bird-hipped dinosaurs were in fact lizard-hipped. The results are reported in the Zoological Journal of the Linnean Society.

Dinosaurs originated in the Late Triassic period, about 225 million years ago, and dominated life on Earth until a mass extinction event 66 million years ago. Dinosaurs have fascinated us since they were first named as such by Richard Owen in 1842.

The earliest discovered dinosaur remains were scrappy: odd-looking teeth and a few bones. By the latter half of the 19th century however, enough dinosaur remains had been found that a classification system was needed. Harry Seeley, who had been trained in Cambridge by Adam Sedgwick, developed such a classification of dinosaurs based primarily upon the shape of their hip bones: they were either saurischians (lizard-hipped) or ornithischians (bird-hipped). This classification, first published in 1888, proved reliable: all dinosaur discoveries seemed to slot neatly into one or other of these groupings.

However, in a 2017 paper, Professor David Norman from Cambridge's Department of Earth Sciences and his former PhD students Matthew Baron and Paul Barrett argued that these dinosaur family groupings need to be rearranged, re-defined and re-named. In a study published in Nature, the researchers suggested that bird-hipped dinosaurs and lizard-hipped dinosaurs such as Tyrannosaurus evolved from a common ancestor, potentially overturning more than a century of theory about the evolutionary history of dinosaurs.

Controversy aside, it has long been recognised that the bird-hipped dinosaurs are clearly anatomically distinct from all other types of dinosaurs, even though they have nothing to do with birds. But how they came to be, has remained a long-standing problem.

"It seemed to be that they originated with all other dinosaurs in the Late Triassic but exhibited a unique set of features that could not be fitted into an evolutionary succession from their dinosaur cousins," said Norman, who is a Fellow of Christ's College. "It was as if they just suddenly appeared out of nowhere."

Recent work has begun to indicate a more varied and puzzling picture of ornithischian origins. From a phylogenetic perspective -- how the dinosaur family tree branches over time -- it is predicted that ornithischian remains should first appear in the fossil record about 225 million years ago.

"However, the more we've looked in rocks of that age, the less we've found," said Norman. "The first unarguable ornithischian remains date from less than 200 million years ago, meaning there is a 25+ million-year ornithischian gap. So far, all attempts to fill that gap have failed."

One solution to this conundrum can be traced back to a discovery in the early years of this century, when the skeleton of an unusual Late Triassic dinosaur-like animal was discovered in Poland. It was described by Jerzy Dzik and named Silesaurus (the 'Silesian lizard').

Silesaurus has long slender legs that gave it an upright dinosaur-like posture -- and its hip bones are arranged like a saurischian -- but it seemed to have a toothless, beak-like region at the front of its lower jaw. This was not unlike the toothless beak-like structure known as a predentary that is found in all ornithischian dinosaur skulls, although the uniquely ornithischian predentary bone was not present.

Its teeth were also constricted at the top of the roots, and the crowns of the teeth were leaf-shaped in profile: a type of tooth shape seen in many early ornithischians. Dzik speculated about the possible ornithischian similarities of Silesaurus, but the suggestion was dismissed or ignored by most researchers.

In the years that followed, more Silesaurus-like creatures were discovered, mostly in South America. Many of these specimens were fragments, but the toothless tip of the lower jaw and the leaf-shaped teeth were common.

The accumulation of these specimens attracted the attention of several researchers. Their analyses suggested that silesaurs were close relatives of true dinosaurs. Either they were placed on a branch just before the origin of true dinosaurs or, in some instances, they appeared as a sister group to Ornithischia. In 2020, Mauricio Garcia and Rodrigo Müller from the Universidade Federal de Santa Maria in Brazil proposed that silesaur-like creatures could sit on the branch of Dinosauria that led to Ornithischia.

"This work attracted our attention in Cambridge," said Norman. "A few years ago, I devised a research project aimed directly at the problem of how the Ornithischia came to be, and Matt was the research student on the project."

Norman and Barron began to collaborate with Rodrigo and Mauricio, enlarging the original analysis to include a range of ornithischian dinosaurs, as well as dinosaur ancestors. The outcome of their collaboration is a family tree that depicts silesaurs as a succession of animals on the stem of the branch leading to Ornithischia.

"Silesaurians progressively modified their anatomy during the Late Triassic, so that they come to resemble ornithischians," said Norman. "We have been able to trace this transition through the development of the toothless beak, the development of leaf-shaped coarse-edged teeth typical of those seen in the herbivorous ornithischians, modifications to the shoulder bones, changes in the proportions of the pelvic bones, and finally a restructuring of the muscle attachment areas on the hind legs."

The research suggests that ornithischians did not arise from nowhere. Rather, they first appeared in the Late Triassic in the guise of silesaurs that gradually rearranged their anatomy with the passage of time until recognisable ornithischians had evolved by the beginning of the Jurassic Period.

However, there is another aspect to this explanation, which is that the earliest ornithischians of the Late Triassic had none of the anatomical characteristics of true ornithischians: they lacked a predentary and, most importantly, retained the early saurischian hip construction.

Read more at Science Daily

A sea change for plastic pollution: New material biodegrades in ocean water

Plastics, now ubiquitous in the modern world, have become a rising threat to human and environmental health. Around the planet, evidence of plastic pollution stretches from grocery bags in the deep sea to microplastics in our food supplies and even in our blood.

Seeking solutions to counteract the rise in plastic trash, scientists at the University of California San Diego have developed new biodegradable materials that are designed to replace conventionally used plastic. After proving their polyurethane foams biodegrade in land-based composts, an interdisciplinary team of scientists including UC San Diego biologist Stephen Mayfield and chemists Michael Burkart and Robert "Skip" Pomeroy have now shown that the material biodegrades in seawater. The results are published in the journalScience of the Total Environment.

The researchers are working to address a plastic pollution problem now described as a global environmental crisis. In 2010, researchers estimated that 8 billion kilograms of plastic enter the ocean in a single year, with a steep escalation predicted by 2025. Upon entering the ocean, plastic waste disrupts marine ecosystems, migrates to central locations and forms trash gyres such as the Great Pacific Garbage Patch, which covers an area more than 1.6 million square kilometers. These plastics never degrade, but rather break up into ever-smaller particles, eventually becoming microplastics that persist in the environment for centuries.

Working with study coauthor Samantha Clements, a marine biologist and scientific diver at Scripps Institution of Oceanography, the UC San Diego researchers conducted a series of tests of their biodegradable polyurethane materials -- currently used as foams in the first commercially available biodegradable shoes (sold by a spinoff company called Blueview) -- at Scripps' Ellen Browning Scripps Memorial Pier and Experimental Aquarium. The pier's location provided scientists the access and a unique opportunity to test materials in the natural nearshore ecosystem, which is the exact environment where rogue plastics are most likely to end up.

The team found that an assortment of marine organisms colonizes on the polyurethane foam and biodegrades the material back to their starting chemicals, which are consumed as nutrients by these microorganisms, in the ocean environment. Data from the study suggest that the microorganisms, a mix of bacteria and fungi, live throughout the natural marine environment.

"Improper disposal of plastic in the ocean breaks down into microplastics and has become an enormous environmental problem," said Mayfield, a professor in the School of Biological Sciences and director of the California Center for Algae Biotechnology. "We've shown that it's absolutely possible to make high performance plastic products that also can degrade in the ocean. Plastics should not be going into the ocean in the first place, but if they do, this material becomes food for microorganisms and not plastic trash and microplastics that harm aquatic life."

Shoes, including flip-flops, the world's most popular shoe, make up a large percentage of plastic waste that ends up in the world's oceans and landfills. To fully test and analyze their polyurethane materials, developed at UC San Diego over the last eight years, the study joined experts in biology, polymer and synthetic chemistry and marine science. Foam samples were exposed to tidal and wave dynamics and tracked for molecular and physical changes using Fourier-transform infrared spectroscopy and scanning electron microscopy. The results showed that the material started to degraded in as little as four weeks. The researchers then identified microorganisms from six marine sites around San Diego that are capable of breaking down and consuming the polyurethane material.

"No single discipline can address these universal environmental problems but we've developed an integrated solution that works on land -- and now we know also biodegrades in the ocean," said Mayfield. "I was surprised to see just how many organisms colonize on these foams in the ocean. It becomes something like a microbial reef."

Read more at Science Daily

Chimpanzee stone tool diversity

During fieldwork aimed at documenting the stone tool use of a group of wild chimpanzees in the Taï Forest in Cote d'Ivoire in early 2022, the researchers identified and 3D scanned a variety of stone tools used to crack different nut species.

It has long been shown that various chimpanzee groups possess different tool use cultures involving wooden and stone tools, however, only some groups in West Africa use stone tools to crack open nuts. By comparing the 3D models of different stone tools used by chimpanzees in the Taï Forest to those from another group in Guinea, the researchers showed that there exist notable differences between the two groups in terms of their material culture.

The study shows that this particular group of chimpanzees in Guinea uses stone hammers varying in the type of stone and sizes, and very large stone anvils, sometimes greater than one meter in length. These durable stone tools are widespread across the landscape; preserve different levels of damage related to their use and represent a lasting record of chimpanzee behaviours.

Stone tools used for nut cracking can differ between chimpanzee groups

This study highlights the fact that, although several groups of chimpanzees practice nut cracking, the tools they use can differ significantly from one another, potentially leading to group specific material signatures. These differences are driven by a combination of stone choice, stone availability, and the nut species eaten.

Previous research has shown, that by using stone tools, some groups of chimpanzees develop their own archaeological record dating to at least 4,300 years ago. "The ability to identify regional differences in stone tool material culture in primates opens up a range of possibilities for future primate archaeological studies," says Tomos Proffitt from the Max Planck Institute of Evolutionary Anthropology, who led the research.

It has been hypothesised that a simple technology, like nut cracking, was a precursor to more complex stone technologies during the early stages of our own evolution more than three million years ago. Proffitt continues, "by understanding what this simple stone tool technology looks like, and how it varies between groups, we can start to understand how to better identify this signature in the earliest hominin archaeological record."

From Science Daily

The aviation industry needs to overhaul its response to climate change

Aviation's growing impact on the climate crisis requires radical solutions that may upend the industry, according to a new Nature commentary article from the University of California San Diego School of Global Policy and Strategy.

Globally, the industry generates roughly 1 billion tons of CO2 per year, which is comparable to Japan, the world's third largest economy. Moreover, emissions from flights have been rising by about 2.5% each year. Without bold solutions, the industry is on track to, over the next 30 years, produce more CO2 than that of its whole history.

While renewable energy has scaled up to replace fossil fuels in power generation and both supply and demand of electric vehicles continues to increase, no carbon-free replacement technologies exist at adequate scale to address pollution from aircraft.

"Most strategies that governments and firms are pursuing today rely on familiar technologies. That approach looks shortsighted because many of these technologies don't work at scale," said coauthor David Victor, professor of innovation and public policy at the UC San Diego School of Global Policy and Strategy co-director of the Deep Decarbonization Initiative. "Eliminating aviation's impact on global warming requires major disruptions to how the industry operates today. The longer that reality is evaded, the harder it will be to find effective solutions."

The Nature piece comes ahead of assembly of the International Civil Aviation Organization (ICAO) in Montreal, Canada, from Sept. 27 to Oct. 7, where representatives from 193 nations will try to negotiate an industry-wide target for cutting emissions from the sector.

Victor and coauthor Steffen Kallbekken of the Center for International Climate Research outline why the two most commonly proposed solutions -- cleaner fuels and carbon offsetting -- that will likely be discussed at the meeting are grossly inadequate.

Carbon offsetting is a reduction or removal of emissions of greenhouse gases (e.g., through land restoration or the planting of trees) that is used to compensate for emissions that occur elsewhere. According to the authors, the track record of reliable accounting in these industries is poor.

"Even with oversight, forest projects are often plagued by wild assumptions, for example that trees would disappear from these areas in the absence of those projects," they write.

On the other hand, cleaner aviation fuel, which currently comes from conventional biofuel feedstocks such as vegetable oils, may be impossible to produce sustainably in sufficient volumes and at low enough prices to replace all jet fuel. Achieving the levels of clean fuel adoption that many governments and firms aim for -- and doing so sustainably -- will require commercializing new production methods and feedstocks that are still technologically in their infancy.

And neither of these solutions are sure to address the climate impacts of contrails, which trap heat radiating from the earth's surface, causing warming in the atmosphere below.

Solutions should be designed to disrupt

In fact, the warming effects of contrails are still poorly understood by climate scientists and therefore given little attention by industry and governments working on decarbonizing aviation. It's possible that the effects are small and could be largely managed by rerouting aircraft around the weather conditions that generate the worst contrails. But the effects could also be massive -- up to half the total climate impact of aviation, according to some studies -- and require entirely new aviation technologies and approaches to cutting the impact of aviation on the climate.

The study argues that addressing contrails may require profound overhauling of engines, airframes and onboard storage -- big, costly and financially risky decisions. The authors urge for more experimentation to test what really could work -- backed by government policies and industry collaborations.

"Resistance to efforts disruptive to the industry's status quo are understandable because airlines often operate on razor thin margins," Victor added. "A growing number of airlines want to do something about climate but are stuck with few practical options."

Victor and Kallbekken recommend three steps for the industry to take to create bold solutions to address a warming planet.

First, the industry and government need to do their homework. They must become more aware of the risks associated with the current approach to aviation's role in the climate crisis.

Second, small collaborations between the most motivated governments and firms could be formed totake risks on new technologies, which could, in turn, inspire others to follow their lead. For example, a partnership between the Norwegian government and businesses is underway to create test bed for electric airplanes.

The authors provide concrete strategies of how other collaborations could be established to potentially ignite other advances. For example, such groups, by sharing costs and risk, could invest in more varied response strategies, including hydrogen, electricity and a cleaner, more scalable version of sustainable aviation fuel. They look to Europe to take the lead since European governments are already highly motivated to take the climate problem seriously.

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Machine learning generates 3D model from 2D pictures

Researchers from the McKelvey School of Engineering at Washington University in St. Louis have developed a machine learning algorithm that can create a continuous 3D model of cells from a partial set of 2D images that were taken using the same standard microscopy tools found in many labs today.

Their findings were published Sept. 16 in the journal Nature Machine Intelligence.

"We train the model on the set of digital images to obtain a continuous representation," said Ulugbek Kamilov, assistant professor of electrical and systems engineering and of computer science and engineering. "Now, I can show it any way I want. I can zoom in smoothly and there is no pixelation."

The key to this work was the use of a neural field network, a particular kind of machine learning system that learns a mapping from spatial coordinates to the corresponding physical quantities. When the training is complete, researchers can point to any coordinate and the model can provide the image value at that location.

A particular strength of neural field networks is that they do not need to be trained on copious amounts of similar data. Instead, as long as there is a sufficient number of 2D images of the sample, the network can represent it in its entirety, inside and out.

The image used to train the network is just like any other microscopy image. In essence, a cell is lit from below; the light travels through it and is captured on the other side, creating an image.

"Because I have some views of the cell, I can use those images to train the model," Kamilov said. This is done by feeding the model information about a point in the sample where the image captured some of the internal structure of the cell.

Then the network takes its best shot at recreating that structure. If the output is wrong, the network is tweaked. If it's correct, that pathway is reinforced. Once the predictions match real-world measurements, the network is ready to fill in parts of the cell that were not captured by the original 2D images.

The model now contains information of a full, continuous representation of the cell -- there's no need to save a data-heavy image file because it can always be recreated by the neural field network.

And, Kamilov said, not only is the model an easy-to-store, true representation of the cell, but also, in many ways, it's more useful than the real thing.

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Chemical cocktail in skin summons disease-spreading mosquitoes

Mosquitoes that spread Zika, dengue and yellow fever are guided toward their victims by a scent from human skin. The exact composition of that scent has not been identified until now.

A UC Riverside-led team discovered that the combination of carbon dioxide plus two chemicals, 2-ketoglutaric and lactic acids, elicits a scent that causes a mosquito to locate and land on its victim. This chemical cocktail also encourages probing, the use of piercing mouthparts to find blood.

This chemical mixture appears to specifically attract female Aedes aegypti mosquitoes, vectors of Zika as well as chikungunya, dengue, and yellow fever viruses. This mosquito originated in Africa, but has spread to tropical and subtropical regions worldwide, including the U.S.

This new research finding, and how the team discovered it, is detailed in the journal Scientific Reports. "Though others have identified compounds that attract mosquitoes, many of them don't elicit a strong, rapid effect. This one does," said Ring Cardé, UCR entomologist.

Mosquitoes use a variety of cues to locate their victims, including carbon dioxide, sight, temperature, and humidity. However, Cardé's recent research shows skin odors are even more important for pinpointing a biting site.

"We demonstrated that mosquitoes land on visually indistinct targets imbued with these two odors, and these targets aren't associated with heat or moisture," Cardé said. "That leaves skin odor as the key guiding factor."

Given the significance of odor in helping mosquitoes successfully feed on humans, Cardé wanted to discover the exact chemicals that make our scent so potent for the insects. Part of the equation, lactic acid, was identified as one chemical element in the odor cocktail as long ago as 1968.

Since then, several studies have identified that carbon dioxide combined with ammonia, and other chemicals produced by humans also attract these mosquitoes. However, Cardé, who has studied mosquitoes for 26 years, felt these other chemicals were not strong attractants.

"I suspected there was something undiscovered about the chemistry of odors luring the yellow fever mosquito," Cardé said. "I wanted to nail down the exact blend."

Methods that chemists typically use to identify these chemicals would not have worked for 2-ketoglutaric acid, Cardé said. Gas chromatography, which separates chemicals by their molecular weight and polarity, would have missed this acid.

"I think that these chemicals may not have been found before because of the complexity of the human odor profile and the minute amounts of these compounds present in sweat," said chemist Jan Bello, formerly of UCR and now with insect pest control company Provivi.

Searching for mosquito attractors, Cardé turned to Bello, who extracted compounds from the sweat in his own feet. He filled his socks with glass beads and walked around with the beads in his socks for four hours per odor collection.

"Wearing the beads felt almost like a massage, like squeezing stress balls full of sand, but with your feet," said Bello. 'The most frustrating part of doing it for a long time is that they would get stuck in between your toes, so it would be uncomfortable after a while."

The inconvenience was worth the investment. Bello isolated chemicals from the sweat deposited on the sock beads and observed the mosquitoes' response to those chemicals. In this way, the most active combination emerged.

Future studies are planned to determine whether the same compound is effective for any other mosquitoes, and why there is such variation in how individuals are apt to be bitten. "Some are more attractive than others to these mosquitoes, but no one's yet established why this is so," Cardé said.

Though this discovery may not lead to insights for the development of new repellants, the research team is hopeful their discovery can be used to attract, trap, and potentially kill disease-spreading mosquitoes.

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Scientist helps identify new evidence for habitability in Enceladus's ocean

The search for extraterrestrial life just got more interesting as a team of scientists including Southwest Research Institute's Dr. Christopher Glein has discovered new evidence for a key building block for life in the subsurface ocean of Saturn's moon Enceladus. New modeling indicates that Enceladus's ocean should be relatively rich in dissolved phosphorus, an essential ingredient for life.

"Enceladus is one of the prime targets in humanity's search for life in our solar system," said Glein, a leading expert in extraterrestrial oceanography. He is a co-author of a paper in the Proceedings of the National Academy of Sciences (PNAS) describing this research. "In the years since NASA's Cassini spacecraft visited the Saturn system, we have been repeatedly blown away by the discoveries made possible by the collected data."

The Cassini spacecraft discovered Enceladus's subsurface liquid water and analyzed samples as plumes of ice grains and water vapor erupted into space from cracks in the moon's icy surface.

"What we have learned is that the plume contains almost all the basic requirements of life as we know it," Glein said. "While the bioessential element phosphorus has yet to be identified directly, our team discovered evidence for its availability in the ocean beneath the moon's icy crust."

One of the most profound discoveries in planetary science over the past 25 years is that worlds with oceans beneath a surface layer of ice are common in our solar system. Such worlds include the icy satellites of the giant planets, such as Europa, Titan and Enceladus, as well as more distant bodies like Pluto. Worlds like Earth with surface oceans must reside within a narrow range of distances from their host stars to maintain the temperatures that support surface liquid water. Interior water ocean worlds, however, can occur over a much wider range of distances, greatly expanding the number of habitable worlds likely to exist across the galaxy.

"The quest for extraterrestrial habitability in the solar system has shifted focus, as we now look for the building blocks for life, including organic molecules, ammonia, sulfur-bearing compounds as well as the chemical energy needed to support life," Glein said. "Phosphorus presents an interesting case because previous work suggested that it might be scarce in the ocean of Enceladus, which would dim the prospects for life."

Phosphorus in the form of phosphates is vital for all life on Earth. It is essential for the creation of DNA and RNA, energy-carrying molecules, cell membranes, bones and teeth in people and animals, and even the sea's microbiome of plankton.

Team members performed thermodynamic and kinetic modeling that simulates the geochemistry of phosphorus based on insights from Cassini about the ocean-seafloor system on Enceladus. In the course of their research, they developed the most detailed geochemical model to date of how seafloor minerals dissolve into Enceladus's ocean and predicted that phosphate minerals would be unusually soluble there.

"The underlying geochemistry has an elegant simplicity that makes the presence of dissolved phosphorus inevitable, reaching levels close to or even higher than those in modern Earth seawater," Glein said. "What this means for astrobiology is that we can be more confident than before that the ocean of Enceladus is habitable."

Read more at Science Daily

Plant breeding: Using 'invisible' chromosomes to pass on packages of positive traits

The ideal crop plant is tasty and high-yielding while also being resistant to diseases and pests. But if the relevant genes are far apart on a chromosome, some of these positive traits can be lost during breeding. To ensure that positive traits can be passed on together, researchers at Karlsruhe Institute of Technology (KIT) have used CRISPR/Cas molecular scissors to invert and thus genetically deactivate nine-tenths of a chromosome. The traits coded for on this part of the chromosome become "invisible" for genetic exchange and can thus be passed on unchanged. The researchers have reported on their findings in Nature Plants.

Targeted editing, insertion or suppression of genes in plants is possible with CRISPR/Cas molecular scissors. (CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats.) This method can be used to make plants more resistant to pests, diseases or environmental influences. "In recent years, we were able for the first time to use CRISPR/Cas not only to edit genes but also to change the structure of chromosomes," says Professor Holger Puchta, who for 30 years has been researching applications for gene scissors with his team at KIT's Botanical Institute. "Genes are linearly arranged along chromosomes. By changing their sequence, we were able to show how desired traits in plants can be separated from undesired ones."

Now the researchers have been able to prevent the genetic exchange that is normally part of the hereditary process but can break the links between traits. "We can shut down a chromosome almost completely, making it seem invisible, so that all traits on that chromosome can be passed on in a package," says Puchta. Until now, if a plant's traits were to be passed on together, the genes for those traits needed to be close to each other on the same chromosome. If such genes are spread farther apart on a chromosome, they are usually separated during inheritance, so a beneficial trait can be lost during the breeding process.

Learning from Nature: Chromosome Engineering Prevents Genetic Exchange

In their research, the scientists followed nature's example. "These reversals, or inversions -- a kind of genetic invisibility -- also occur frequently on a smaller scale in wild and cultivated plants. We've learned from nature and have applied and extended our knowledge about the natural process," says Puchta.

In collaboration with Professor Andreas Houben from the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Puchta and his team inverted nine-tenths of a chromosome in the model organism Arabidopsis thaliana (thale cress). Only at the ends of the chromosome did the genes retain their original sequence. "With these fragments, the chromosome can be passed on to the next generation just like the other chromosomes and is not completely lost," says Puchta.

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Scientists find that wolves can show attachment toward humans

When it comes to showing affection towards people, many dogs are naturals. Now comes word reported in the journal Ecology and Evolution on September 20th that the remarkable ability to show attachment behaviour toward human caregivers also exists in wolves.

The findings were made when researchers at Stockholm University, Sweden, tested 10 wolves and 12 dogs in a behavioural test specifically designed to quantify attachment behaviours in canids. During this test 23-week-old wolves spontaneously discriminated between a familiar person and a stranger just as well as dogs did, and showed more proximity seeking and affiliative behaviours towards the familiar person. Additionally, the presence of the familiar person acted as a social stress buffer for the wolves calming them in a stressful situation. These discoveries build on a slowly accumulating body of evidence contradicting the hypothesis that the abilities necessary to form attachment with humans, arose in dogs only after humans domesticated them at least 15,000 years ago.

"We felt that there was a need to thoroughly test this," says Dr. Christina Hansen Wheat, PhD in Ethology from Stockholm University, Sweden. "Together with earlier studies making important contributions to this question, I think it is now appropriate to entertain the idea that if variation in human-directed attachment behaviour exists in wolves, this behaviour could have been a potential target for early selective pressures exerted during dog domestication."

Dr. Hansen Wheat is interested in understanding how domestication affects behaviour. To study this, she and her team raised wolf and dog puppies from the age of 10 days and put them through various behavioural tests. In one of those tests, a familiar person and a stranger takes turn in coming in and out of a test room to create a somewhat strange and stressful situation for the animal. The theory behind the test, originally developed to assess attachment in human infants, is that by creating this unstable environment attachment behaviours, such as proximity seeking, will be stimulated.

In essence, what the researchers were looking for in this Strange Situation Test was if the wolves and dogs could discriminate between the familiar person and the stranger. That is, did they show more affection, and spend more time greeting and in physical contact with the familiar person than the stranger. If wolves and dogs would do so equally it would point towards this ability not being unique to dogs, i.e. it has not evolved specifically in dogs.

"That was exactly what we saw," says Dr. Hansen Wheat. "It was very clear that the wolves, as the dogs, preferred the familiar person over the stranger. But what was perhaps even more interesting was that while the dogs were not particularly affected by the test situation, the wolves were. They were pacing the test room. However, the remarkable thing was that when the familiar person, a hand-raiser that had been with the wolves all their lives, re-entered the test room the pacing behaviour stopped, indicating that the familiar person acted as a social stress buffer for the wolves. I do not believe that this has ever been shown to be the case for wolves before and this also complements the existence of a strong bond between the animals and the familiar person."

Dr. Hansen Wheat adds that similarities between dogs and wolves can tell us something about where the behaviour we see in our dogs come from. And, while it may be a surprise to some that wolves can connect with a person in this way, she says in retrospect it also makes sense.

Read more at Science Daily

Pando in pieces: Understanding the new breach in the world's largest living thing

It's ancient, it's massive, and it is faltering. The gargantuan aspen stand dubbed 'Pando,' located in south-central Utah, is more than 100 acres of quivering, genetically identical plant life, thought to be the largest living organism on earth (based on dry weight mass, 13 million pounds). What looks like a shimmering panorama of individual trees is actually a group of genetically identical stems with an immense shared root system.

Now, after a lifetime that may have stretched across millennia, the 'trembling giant' is beginning to break up, according to new research.

Paul Rogers, adjunct professor of ecology in the Quinney College of Natural Resources and director of the Western Aspen Alliance, completed the first comprehensive evaluation of Pando five years ago. It showed that browsing deer (and to a lesser degree cattle) were harming the stand -- limiting growth of new aspen suckers and putting an effective expiration date on the colossal plant. As older trees aged-out, new aspen sprouts weren't surviving voracious browsers to replace them. Pando was slowly dying.

In response to the threat, managers erected fencing around a section of the stand to keep grazing animals out, creating an experiment of sorts. Rogers recently returned to evaluate the strategy, and to do a well-check on the overall health of Pando. He reported his findings in the journal Conservation Science and Practice.

Pando seems to be taking three disparate ecological paths based on how the segments are managed, according to the research. Around 16 percent of the stand is adequately fenced to keep out browsing animals; new aspen suckers surviving those first tender years to establish into new trees. But across more than a third of the stand, fencing had fallen into disrepair and was only lately reinforced. Past browsing still has adverse impacts in this section; old and dying trees still outnumbering the young.

And the areas that remain unfenced (approximately 50 percent of the stand) continue to have concentrated levels of deer and cattle consuming the bulk of young sprouts. These hard-hit zones are now shifting ecologically in distinct ways, said Rogers. Mature aspen stems die without being replaced, opening the overstory and allowing more sunlight to consistently reach the forest floor, which alters plant composition. These unfenced areas are experiencing the most rapid aspen decline, while the other fenced areas are taking their own unique courses -- in effect, breaking up this unique, historically uniform, forest.

The solution to Pando's survival, said Rogers, might not be just more fencing. While unfenced areas are rapidly dying off, fencing alone is encouraging single-aged regeneration in a forest that has sustained itself over the centuries by varying growth. While this may not seem critical, aspen and understory growth patterns at odds from the past are already occurring, said Rogers.

In Utah and across the West, Pando is iconic, and something of a canary in the coal mine. As a keystone species, aspen forests support high levels of biodiversity -- from chickadees to thimbleberry. As aspen ecosystems flourish or diminish, myriad dependent species follow suit. Long-term failure for new recruitment in aspen systems may have cascading effects on hundreds of species dependent on them.

Additionally, there are aesthetic and philosophical problems with a fencing strategy, said Rogers.

"I think that if we try to save the organism with fences alone, we'll find ourselves trying to create something like a zoo in the wild," said Rogers. "Although the fencing strategy is well-intentioned, we'll ultimately need to address the underlying problems of too many browsing deer and cattle on this landscape."

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Astro­physics: Star-child­hood shapes stel­lar evo­lu­tion

In classical models of stellar evolution, so far little importance has been attached to the early evolution of stars. Scientists now show that the biography of stars is indeed shaped by their early stage.

From babies to teenagers: stars in their "young years" are a major challenge for science. The process of star formation is particularly complex and difficult to map in theoretical models. One of the few ways to learn more about the formation, structure or age of stars is to observe their oscillations. "Comparable to the exploration of the Earth's interior with the help of seismology, we can also make statements about their internal structure and thus also about the age of stars based on their oscillations" says Konstanze Zwintz. The astronomer is regarded as a pioneer in the young field of asteroseismology and heads the research group "Stellar Evolution and Asteroseismology" at the Institute for Astro- and Particle Physics at the University of Innsbruck. The study of stellar oscillations has evolved significantly in recent years because the possibilities for precise observation through telescopes in space such as TESS, Kepler, and James Webb have improved on many levels. These advances are now also shedding new light on decades-old theories of stellar evolution.

With a new model to zero hour of adult stars

Stars are called "children" as long as they are not yet burning hydrogen to helium in their cores. At this stage, they are on the pre-main sequence; after ignition, they become adults and move onto the main sequence. "Research on stars has so far focused mainly on adult stars -- such as our Sun" says Thomas Steindl, a member of Konstanze Zwintz's research group and lead author of the study. "Even if it sounds counterintuitive at first glance, so far little attention has been paid to the evolution of the pre-main sequence because the phase is very turbulent and difficult to model. It's only the technological advances of recent years that allow us a closer look at the infancy of stars -- and thus at that moment when the star begins to fuse hydrogen into helium." In their current study, the two Innsbruck researchers now present a model that can be used to realistically depict the earliest phases of a star's life long before they become adults. The model is based on the open-source stellar evolution program MESA (Modules for Experiments in Stellar Astrophysics).

Inspired by a talk given by astronomer Eduard Vorobyov of the University of Vienna at a 2019 meeting, Thomas Steindl spent months refining the method for using this stellar evolution code to recreate the chaotic phase of early star formation and then predict their specific oscillations. "Our data show that stars on the pre-main sequence take a very chaotic course in their evolution. Despite its complexity, we can now use it in our new theoretical model." Steindl said. Thus, the astronomer shows that the way the star is formed has an impact on the oscillation behaviour even after ignition of nuclear fusion on the main sequence: "The infancy has an influence on the later pulsations of the star: This sounds very simple, but it was strongly in doubt. The classical theory assumes that the time before ignition is simply irrelevant. This is not true: Comparable to a musical instrument, even subtle differences in the composition lead to significant changes in the tone. Thus, our modern models better describe the oscillations in real stars."

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Geologist proposes the number of ancient Martian lakes might have been dramatically underestimated by scientists

Lakes are bodies of water fed by rainfall, snowmelt, rivers and groundwater, through which, Earth is teeming with life. Lakes also contain critical geologic records of past climates. Though Mars is a frozen desert today, scientists have shown that Mars contains evidence of ancient lakes that existed billions of years ago, which could contain evidence for ancient life and climate conditions on the red planet. Through a meta-analysis of years of satellite data that shows evidence for lakes on Mars, Dr Joseph Michalski, a geologist in the Department of Earth Sciences, The University of Hong Kong (HKU) proposed that scientists might have dramatically underestimated the number of ancient Martian lakes that once existed.

Michalski and the international team recently published their results in Nature Astronomy, which describe a global analysis of ancient Martian lakes. "We know of approximately 500 ancient lakes deposited on Mars, but nearly all the lakes we know about are larger than 100 km2," explains Michalski. "But on Earth, 70% of the lakes are smaller than this size, occurring in cold environments where glaciers have retreated. These small-sized lakes are difficult to identify on Mars by satellite remote sensing, but many small lakes probably did exist. It is likely that at least 70% of Martian lakes have yet to be discovered." Scientists monitor these small lakes on Earth in order to understand climate change. The missing small lakes on Mars might also contain critical information about past climates.

The recent paper also reports that most known Martian lakes date to a period 3,500 to 4,000 million years ago, but each of the lakes might have lasted only a geologically short time (10,000 to 100,000 years) during this time span. This means that ancient Mars was probably mostly cold and dry as well, but it warmed episodically for short periods of time. Michalski adds, "Because of the lower gravity on Mars and the pervasive, fine-grained soil, lakes on Mars would have been very murky and might not have allowed light to penetrate very deeply, which could present a challenge to photosynthetic life, if it existed."

Lakes contain water, nutrients and energy sources for possible microbial life, including light for photosynthesis. Therefore, lakes are the top targets for astrobiological exploration by Mars Rovers such as NASA's Perseverance rover now on Mars. But Michalski warns, "Not all lakes are created equal. In other words, some Martian lakes would be more interesting for microbial life than others because some of the lakes were large, deep, long-lived and had a wide range of environments such as hydrothermal systems that could have been conducive to the formation of simple life." From this point of view, it might make sense to target large, ancient, environmentally diverse lakes for future exploration.

"Earth is host to many environments that can serve as analogs to other planets. From the harsh terrain of Svalbard to the depths of Mono Lake -- we can determine how to design tools for detecting life elsewhere right here at home. Most of those tools are aimed at detecting the remains and residues of microbial life," said Dr David BAKER, an ecologist at HKU School of Biological Sciences who is well-informed about the Earth's microbial systems in lakes.

China successfully landed its first lander, Zhurong, on Mars in May this year. Zhurong is currently roving the plains of Utopia Planitia, exploring mineralogical and chemical clues to recent climate change. China is also planning a sample return mission likely to occur at the end of this decade, which could target one of the interesting lake deposits.

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Mexican mangroves have been capturing carbon for 5,000 years

Researchers have identified a new reason to protect mangrove forests: they've been quietly keeping carbon out of Earth's atmosphere for the past 5,000 years.

Mangroves thrive in conditions most plants cannot tolerate, like salty coastal waters. Some species have air-conducting, vertical roots that act like snorkels when tides are high, giving the appearance of trees floating on stilts.

A UC Riverside and UC San Diego-led research team set out to understand how marine mangroves off the coast of La Paz, Mexico, absorb and release elements like nitrogen and carbon, processes called biogeochemical cycling.

As these processes are largely driven by microbes, the team also wanted to learn which bacteria and fungi are thriving there.

The team expected that carbon would be found in the layer of peat beneath the forest, but they did not expect that carbon to be 5,000 years old. This result, along with a description of the microbes they identified, is now published in the journal Marine Ecology Progress Series.

"What's special about these mangrove sites isn't that they're the fastest at carbon storage, but that they have kept the carbon for so long," said Emma Aronson, UCR environmental microbiologist and senior co-author of the study. "It is orders of magnitude more carbon storage than most other ecosystems in the region."

Peat underlying the mangrove trees is a combination of submerged sediment and partially decayed organic matter. In some areas sampled for this study, the peat layer extended roughly 10 feet below the coastal water line.

Little oxygen makes it to the deepest peat layer, which is likely why the team did not find any fungi living in it; normally fungi are found in nearly every environment on Earth. However, oxygen is a requirement for most fungi that specialize in breaking down carbon compounds. The team may explore the absence of fungi further in future mangrove peat studies.

There are more than 1,100 types of bacteria living beneath the mangroves that consume and excrete a variety of chemical elements. Many of them function in extreme environments with low or no oxygen. However, these bacteria are not efficient at breaking down carbon.

The deeper you go into the peat soils, the fewer microorganisms you find. Not much can break down the carbon down there, or the peat itself, for that matter," said Mia Maltz, UCR microbial ecologist and study author. "Because it persists for so long, it's not easy to make more of it or replicate the communities of microbes within it."

There are other ecosystems on Earth known to have similarly aged or even older carbon. Arctic or Antarctic permafrost, where the ice hasn't yet thawed allowing a release of gases, are examples. Potentially, other mangrove forests as well. The researchers are now scouting mangrove research sites in Hawaii, Florida and Mexico's Yucatan Peninsula as well.

"These sites are protecting carbon that has been there for millennia. Disturbing them would cause a carbon emission that we wouldn't be able to repair any time soon," said Matthew Costa, UC San Diego coastal ecologist and first author on the paper.

Carbon dioxide increases the greenhouse effect that is causing the planet to heat up. Costa believes that one way to keep this issue from worsening is to leave mangroves undisturbed.

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Scientists imbue cells with pathway to make own drugs

Thank the rare crested ibis for a clue that could someday help our bodies make better drugs.

The species of bird is the only one known to naturally produce an enzyme able to generate a noncanonical amino acid; that is, one not among the 20 necessary to encode most proteins.

That it exists -- a discovery made through computational comparison of genome databases -- proves it's possible for that enzyme to work within the context of living cells, even if scientists don't know what it does for the bird.

But they have a pretty good idea of what it could do for us.

A new study by Rice University chemist Han Xiao, theoretical physicist Peter Wolynes and their colleagues shows that amino acid, sulfotyrosine (sTyr), a mutant of the standard amino acid tyrosine, is a key building block to program living cells that express therapeutic proteins. It could potentially allow cells to serve as sensors that monitor their environments and respond with the necessary treatment.

Mimicking the ibis' ability to synthesize sTyr and incorporate it into proteins requires modifying a cell's DNA with a mutant codon that, in turn, makes the transferase enzyme, sulfotransferase 1C1, found in the bird. This catalyzes the generation of sTyr, an essential recognition moiety in a variety of biomolecular interactions.

The proof-of-concept study produced for the first time mammalian cells that synthesize sTyr. In an experiment, the Xiao lab made cells that enhanced the potency of thrombin inhibitors, anticoagulants used to prevent blood clotting.

The study appears in Nature Communications.

"In nature, most of our species are made with 20 canonical building blocks," Xiao said. "If you want to add an additional building block, you need to think about how to make it. We solved that problem: We can ask the cell to make it.

"But then we have to have the translational machinery to recognize it. And a special codon to encode this new building block," he said. "With this study, we've fulfilled all three of these requirements."

Xiao received a National Institutes of Health grant in 2019 to see if cells could be programmed to make substances with extra amino acids. The new study demonstrates the lab's dramatic progress.

Up to now, scientists would feed chemically synthesized noncanonical amino acids into cells. Having the cell do the work is far more efficient, Xiao said, but that requires the discovery of a new transferase enzyme with tyrosine pockets that could bind sulfate. That lock-and-key combination could then be used as the foundation for a variety of catalysts.

"Now, through this new strategy to modify proteins, we can totally change a protein's structure and its function," he said. "For our thrombin inhibitors models, we showed that putting an unnatural building block in the drug can make the drug much more potent."

It was worth a look to see if nature had beaten them to a useful codon. For that, Xiao enlisted Wolynes, co-director of the Center for Theoretical Biological Physics, whose lab compared genome databases and found sulfotransferase 1C1 in the ibis.

The Xiao lab employed a mutant amber stop codon, a three-nucleotide group of uracil, adenine and guanine, to encode the desired sulfotransferase, resulting in a completely autonomous mammalian cell line capable of biosynthesizing sTyr and incorporating it with great precision into proteins.

"We got lucky," Xiao said. "Ibis is the only species doing this, which was discovered by a sequence similarity search of genomic information. After that, we asked if they can figure out why this enzyme recognizes tyrosine but our human sulfotransferase cannot."

The Wolynes team employed AlphaFold2, an artificial intelligence program developed by Alphabet/Google's DeepMind that predicts proteins structures.

The researchers expect to use the combination of bioinformatics and computationally enhanced screening to produce a library of biosynthesized noncanonical amino acids.

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NASA's Perseverance rover investigates geologically rich Mars terrain

NASA's Perseverance rover is well into its second science campaign, collecting rock-core samples from features within an area long considered by scientists to be a top prospect for finding signs of ancient microbial life on Mars. The rover has collected four samples from an ancient river delta in the Red Planet's Jezero Crater since July 7, bringing the total count of scientifically compelling rock samples to 12.

"We picked the Jezero Crater for Perseverance to explore because we thought it had the best chance of providing scientifically excellent samples -- and now we know we sent the rover to the right location," said Thomas Zurbuchen, NASA's associate administrator for science in Washington. "These first two science campaigns have yielded an amazing diversity of samples to bring back to Earth by the Mars Sample Return campaign."

Twenty-eight miles (45 kilometers) wide, Jezero Crater hosts a delta -- an ancient fan-shaped feature that formed about 3.5 billion years ago at the convergence of a Martian river and a lake. Perseverance is currently investigating the delta's sedimentary rocks, formed when particles of various sizes settled in the once-watery environment. During its first science campaign, the rover explored the crater's floor, finding igneous rock, which forms deep underground from magma or during volcanic activity at the surface.

"The delta, with its diverse sedimentary rocks, contrasts beautifully with the igneous rocks -- formed from crystallization of magma -- discovered on the crater floor," said Perseverance project scientist Ken Farley of Caltech in Pasadena, California. "This juxtaposition provides us with a rich understanding of the geologic history after the crater formed and a diverse sample suite. For example, we found a sandstone that carries grains and rock fragments created far from Jezero Crater -- and a mudstone that includes intriguing organic compounds."

"Wildcat Ridge" is the name given to a rock about 3 feet (1 meter) wide that likely formed billions of years ago as mud and fine sand settled in an evaporating saltwater lake. On July 20, the rover abraded some of the surface of Wildcat Ridge so it could analyze the area with the instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC.

SHERLOC's analysis indicates the samples feature a class of organic molecules that are spatially correlated with those of sulfate minerals. Sulfate minerals found in layers of sedimentary rock can yield significant information about the aqueous environments in which they formed.

What Is Organic Matter?

Organic molecules consist of a wide variety of compounds made primarily of carbon and usually include hydrogen and oxygen atoms. They can also contain other elements, such as nitrogen, phosphorus, and sulfur. While there are chemical processes that produce these molecules that don't require life, some of these compounds are the chemical building blocks of life. The presence of these specific molecules is considered to be a potential biosignature -- a substance or structure that could be evidence of past life but may also have been produced without the presence of life.

In 2013, NASA's Curiosity Mars rover found evidence of organic matter in rock-powder samples, and Perseverance has detected organics in Jezero Crater before. But unlike that previous discovery, this latest detection was made in an area where, in the distant past, sediment and salts were deposited into a lake under conditions in which life could potentially have existed. In its analysis of Wildcat Ridge, the SHERLOC instrument registered the most abundant organic detections on the mission to date.

"In the distant past, the sand, mud, and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could potentially have thrived," said Farley. "The fact the organic matter was found in such a sedimentary rock -- known for preserving fossils of ancient life here on Earth -- is important. However, as capable as our instruments aboard Perseverance are, further conclusions regarding what is contained in the Wildcat Ridge sample will have to wait until it's returned to Earth for in-depth study as part of the agency's Mars Sample Return campaign."

The first step in the NASA-ESA (European Space Agency) Mars Sample Return campaign began when Perseverance cored its first rock sample in September 2021. Along with its rock-core samples, the rover has collected one atmospheric sample and two witness tubes, all of which are stored in the rover's belly.

The geologic diversity of the samples already carried in the rover is so good that the rover team is looking into depositing select tubes near the base of the delta in about two months. After depositing the cache, the rover will continue its delta explorations.

"I've studied Martian habitability and geology for much of my career and know first-hand the incredible scientific value of returning a carefully collected set of Mars rocks to Earth," said Laurie Leshin, director of NASA's Jet Propulsion Laboratory in Southern California. "That we are weeks from deploying Perseverance's fascinating samples and mere years from bringing them to Earth so scientists can study them in exquisite detail is truly phenomenal. We will learn so much."

More About the Mission

A key objective for Perseverance's mission on Mars is astrobiology, including caching samples that may contain signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent NASA missions, in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASA's Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

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Infants, young children finally get relief from eczema's terrible itch

The first study to treat moderate-to-severe eczema in infants and children 6 months to 5 years old with a biologic drug (monoclonal antibody) rather than immune-suppressing medications shows the drug was highly effective in reducing the signs and symptoms of moderate-to-severe eczema, report researchers involved in a new multi-site international phase III study led by Northwestern Medicine.

A 16-week course of dupilumab, a medication that targets a key immune pathway in allergies, resulted in more than half the children having at least a 75% reduction in signs of eczema and highly significant reductions in itch with improved sleep.

This is the first large-scale, randomized, placebo-controlled trial of a monoclonal antibody in any skin disease, including eczema, in children as young as 6 months. The study, which included 31 sites in Europe and North America, will be published Sept. 15 in The Lancet.

"Preschoolers who are constantly scratching, awake multiple times a night with their parents, irritable and markedly curtailed in their ability to do what other children their ages can do improved to the extent that they sleep through the night, change their personalities and have a normal life -- as babies and children should," said lead study author Dr. Amy Paller, chair of dermatology at Northwestern University Feinberg School of Medicine and an attending physician at Ann & Robert H. Lurie Children's Hospital of Chicago.

Eczema, also known as atopic dermatitis, is a chronic inflammatory skin disorder characterized by red, dry, often oozing skin and itch that can profoundly affect the lives of affected patients and their families.

An estimated 19% or more of all children under 6 years of age have eczema and 85 to 90% of individuals affected overall with eczema have the onset of disease during the first five years of life.

The children's debilitating itch leads to sleep disturbance, poor neurocognitive development and, on average, a full night of sleep lost per week.

"The ability to take this drug will significantly improve the quality of life for infants and young children who suffer tremendously with this disease," Paller said. "Atopic dermatitis or eczema is so much more than just itchy skin. It is a devastating disease. The quality of life of severe eczema -- not only for the child but also parents -- is equivalent to many life-threatening diseases."

As a result of this study, this medication is now available to infants and preschoolers as young as 6 months of age. It has "an outstanding safety profile" and does not even require any laboratory tests before starting the medication, Paller said.

Although one-half to two-thirds of young children with eczema have mild symptoms, which can be handled with steroid ointment and moisturizers, the other one-third or more have moderate-to-severe disease and require more aggressive management.

"Up to now, all we have had to treat more severe eczema is immune-suppressing medications, such as oral steroids, which we try to avoid in children, because they are associated with so many side effects and thus are not a preferred treatment for a chronic skin disease," Paller said. "The potential long-term impact on the development of the immune system in young children is also of concern with these immunosuppressants."

During the past few years, a new medication has become available called dupilumab, which is the first "biologic" drug to treat eczema in a targeted manner, meaning a narrow attack on just what scientists have found is causing the manifestations of the disease in skin. This medication was found to be effective and safe in studies with adults, then adolescents, then other school-aged children.

"But the group in whom we worry the most about safety -- those under 5 -- had not been tested and were unable to get this medication," Paller said.

The parent or a health care provider gives the child a monthly shot to administer the medication.

"The effect for most of these younger children is dramatic and at least as good as we've seen with the risky immunosuppressant medications," Paller said.

Potential added benefit by treating associated allergies

This medication has also been shown to be effective for treating asthma, gastrointestinal manifestations of allergy and other allergy-mediated problems but is not yet approved for these indications in infants and young children.

In fact, 66% of children in this trial had developed their eczema during the first six months of life and, by the time of initiating the dupilumab, more than 80% had already developed at least one allergic disorder, such as asthma or food allergy.

"By treating more aggressively to calm the immune system activation in these young children with early, severe eczema, we may also reduce the risk of their developing a range of allergic problems, changing their life beyond improving eczema," Paller said. "These associated allergic issues most often begin after the eczema starts."

Children were randomized to receive either a placebo injection or the dupilumab (weight-based dosing) every four weeks for 16 weeks. Only children who were not responding adequately to topical medications were allowed to enroll, and they had to be of a high severity, even with the topical medications.

As a result of the study, Paller said, scientists and physicians can start to better understand the relationships between eczema and a variety of allergic disorders and can consider the possibility of using this medication for other disorders that affect these very young children.

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