Gene mutation linked to learning deficits in 'Clueless' mice

A single mutation in a gene, Kcnc3, which encodes a potassium channel in neurons, causes learning deficits in mice, UT Southwestern researchers report in a new study in PNAS. The novel mutation decreases the activity of neurons in the hippocampus, the area of the brain important for learning and memory, and highlights a new role for potassium channels.

"Learning and memory are very complex at the genetic level. Unbiased searches for genes underlying learning and memory have not been successfully conducted in mice before," said Joseph Takahashi, Ph.D., Professor and Chair of Neuroscience at UT Southwestern and a Howard Hughes Medical Institute Investigator.

The discovery of the Kcnc3 mutation came out of an extraordinary effort by Dr. Takahashi and colleagues to conduct a large-scale mutagenesis screen in mice. Using a highly potent mutagen called ENU, the researchers induced random mutations in the mouse genome. The progeny of ENU-treated mice were then screened for neural and behavioral traits that could be mapped to specific genes to identify the causal mutation. This approach to unbiased gene discovery is called forward genetics.

From the mutagenesis screen, Dr. Takahashi and his team isolated a mutant mouse with spatial learning defects, which they named Clueless. In fear-conditioning tests, the mutants exhibited reduced freezing (a natural fear response in mice) as well as defects in long-term and short-term memory. The defects in Clueless mice mapped to a mutation in the Kcnc3 gene, which encodes a subunit of a special type of potassium channel called a voltage-gated potassium channel.

This is the first study to implicate Kcnc3 in learning, explained Dr. Takahashi, an investigator in UTSW's Peter O'Donnell Jr. Brain Institute. The full Kcnc3 knockout mouse model shows only mild gait issues with no defects in learning and memory, which could be due to developmental compensation or functional redundancy with other voltage-gated potassium channel subunits. Future research will help to answer some of these outstanding questions.

Dr. Takahashi said the findings underscore the power of applying forward genetics to gene discovery and could lead to potential new targets for therapy in learning and memory as well as other disease areas.

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Potential threat to heart health from extreme weather

An analysis in nearly 2.3 million Europeans has found detrimental associations between cold weather and deaths from heart disease, particularly in poor neighbourhoods. The late-breaking research is presented at ESC Congress 2022.1 Hot weather was linked with excess deaths from heart disease and stroke in patients with heart conditions.

Study author Professor Stefan Agewall of the University of Oslo, Norway said: "Climate change is leading to a rise in the average global temperature but also extreme cold in some regions. More than 70,000 excess deaths occurred across Europe during the summer of 2003 due to intense heatwaves.2 Cold weather also accounts for excess deaths and hospital admissions.3,4 Previously studies on the cardiovascular effects of heat and cold mainly used aggregated data, such as daily deaths in a city. The EXHAUSTION project used individual data, enabling us to identify vulnerable subgroups for protective interventions, thereby increasing resilience for future weather events."

The analysis included 2.28 million adults from five cohort studies conducted in Italy, Germany, the UK, Norway, and Sweden between 1994 and 2010. The average age ranged from 49.7 years to 71.7 years and the proportion of women ranged from 36.0% to 54.5%. Participants with and without cardiovascular disease at baseline were included. Data on mortality and new-onset disease were collected through death and disease registries and follow up surveys. Daily average air temperatures at participants' home addresses were collected from local weather stations or estimated using modelling of temperature data from weather stations

The relationships between temperature and cardiovascular conditions and death were analysed for all participants and in subgroups with particular characteristics. A time-stratified case-crossover study design was used where for each participant, the researchers compared the temperature on the day of the week an adverse event occurred (e.g. Monday) with the temperature on the same day of the week without an adverse event (e.g. all remaining Mondays) within the same month. Using within-participant comparisons between days in the same month eliminated the potential confounding effects of participant characteristics and time trends.

The analysis found increased risks of death from cardiovascular disease overall and ischaemic heart disease in particular, as well as an elevated risk of new-onset ischaemic heart disease, associated with cold weather. With an approximately 10°C temperature drop, from 5°C to -5°C, there was a 19% greater risk of death from cardiovascular disease (relative risk [RR] 1.19; 95% confidence interval [CI] 1.04-1.36) and a 22% elevated likelihood of death from ischaemic heart disease (RR 1.22; 95% CI 1.07-1.38). There was a 4% higher risk of new-onset ischaemic heart disease associated with an approximately 11°C temperature drop, from 2°C to -9°C (RR 1.04; 95% CI: 1.01-1.08).

Professor Agewall said: "The relationships between cold temperatures and deaths were more pronounced in men and people living in neighbourhoods with a low socioeconomic status. The links between cold and new-onset ischaemic heart disease were stronger among women and people older than 65 years."

Heat was not related to detrimental effects in the overall study population. However, temperature rises from 15°C to 24°C were associated with 25% (RR 1.25; 95% CI 1.12-1.39) and 30% (RR 1.30; 95% CI 1.10-1.53) elevated risks of death from cardiovascular disease and stroke, respectively, in people with heart disease at baseline.

Professor Agewall said: "Clinicians can use this information to provide tailored advice to those most at risk of adverse health outcomes during hot and cold days. Patients with heart conditions should stay hydrated in hot weather and adhere to advice from their cardiologist on medication use. We can all check the news for extreme heat and cold alerts and follow safety tips from local authorities."

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A historical perspective on glacial retreat

Glaciers are melting rapidly -- and since the 2000s, scientists have been recording and researching changes in their volume more and more precisely. In contrast, hardly anything is known about how glaciers changed during the 20th century. Although there are a handful of studies that reconstruct the surface topography of individual glaciers in the late 19th and early 20th centuries, these partially show large discrepancies with existing models when it comes to estimating the corresponding glacier volume.

In a study that has just been published in the scientific journal The Cryosphere, a team of researchers from ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL have reconstructed the topography of all Swiss glaciers in 1931. Based on these reconstructions and comparisons with data from the 2000s, the researchers conclude that the glacier volume halved between 1931 and 2016.

Old data -- new insights

For their reconstruction, the glaciologists turned to what is known as stereophotogrammetry, a technique that can be used to determine the nature, shape and position of any object on the basis of image pairs. This technique has long been in use in Switzerland: from the First World War until the end of the 1940s, engineers from the Swiss National Survey -- today swisstopo -- surveyed large swathes of the Swiss Alps from some 7,000 locations using phototheodolites (a combination of a camera and an angle measuring device).

The resulting glass plate images, which swisstopo has digitised and enriched with metadata from field books, are now available to the public through the TerrA image archive. The researchers used the material from this image archive, which covers about 86 percent of the glacierised area of Switzerland. They analysed around 21,700 photographs taken between 1916 and 1947. "Based on these photos, we determined the glacier surface topography. If we know the surface topography of a glacier at two different points in time, we can calculate the difference in ice volume," explains lead author Erik Schytt Mannerfelt of ETH Zurich and WSL. Since the images were taken in different years, the researchers decided to use the mean year 1931 as a reference and reconstructed the surface topography of all glaciers for that year.

Not all glaciers are under observation

To date, the picture of glacier changes during the last century has been largely based on a combination of long-term glacier observations, measurements performed in the field and aerial photographs taken after 1960. From this information, glaciologists reconstructed the mass balance of individual glaciers -- that is, the difference between mass gain and mass loss.

One way to determine a glacier's mass balance is through on-site measurements. But only a few Swiss glaciers -- the Claridenfirn, for example -- have been the subject of regular measurements. This means that long time series stretching over several decades are very rare. In addition, older mass balance series can accumulate errors from earlier, inaccurate or uncertain measurements, which can lead to large distortions.

Not all glaciers are equally affected

The study further shows that not all glaciers are losing mass at the same rate. The extent to which they have decreased in volume depends primarily on three factors: first, the altitude at which a glacier is located; second, how flat the glacier snout is; and third, the amount of debris on the glacier.

So have the glaciers just been receding every year? No. While the climate in the 20th century was generally unfavourable for glaciers, in the 1920s and 1980s there was sporadic glacier mass growth, with individual glaciers advancing. "While there may have been growth over short-term periods, it's important to keep the big picture in mind. Our comparison between the years 1931 and 2016 clearly shows that there was significant glacial retreat during this period," says Daniel Farinotti, Professor of Glaciology at ETH Zurich and WSL, and co-author of the study. What's more, the total glacier volume is decreasing at an ever faster rate, as confirmed by the glacier monitoring network GLAMOS, which is managed by ETH Zurich. By way of comparison, while glaciers lost half their volume between 1931 and 2016, they lost a further 12 percent between 2016 and 2021 -- i.e. in just six years.

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Good sleepers have lower risk of heart disease and stroke

Nine in ten people do not get a good night's sleep, according to research presented at ESC Congress 2022.1 The study found that suboptimal sleep was associated with a higher likelihood of heart disease and stroke. The authors estimated that seven in ten of these cardiovascular conditions could be prevented if everyone was a good sleeper.

"The low prevalence of good sleepers was expected given our busy, 24/7 lives," said study author Dr. Aboubakari Nambiema of INSERM (the French National Institute of Health and Medical Research), Paris, France. "The importance of sleep quality and quantity for heart health should be taught early in life when healthy behaviours become established. Minimising night-time noise and stress at work can both help improve sleep."

Previous studies on sleep and heart disease have generally focused on one sleep habit, such as sleep duration or sleep apnoea, where breathing stops and starts while sleeping. In addition, prior studies have often assessed sleep at baseline only. The current study used a healthy sleep score combining five sleep habits. The researchers investigated the association between the baseline sleep score, and changes over time in the sleep score, and incident cardiovascular disease.

This study included 7,200 participants of the Paris Prospective Study III (PPP3), an observational community-based prospective cohort. Men and women aged 50 to 75 years and free of cardiovascular disease were recruited in a preventive medical centre between 2008 and 2011. The average age was 59.7 years and 62% were men. Participants underwent a physical examination and completed questionnaires on lifestyle, personal and family medical history, and medical conditions.

Questionnaires were used to collect information on five sleep habits at baseline and two follow up visits. Each factor was given 1 point if optimal and 0 if not. A healthy sleep score ranging from 0 to 5 was calculated, with 0 or 1 considered poor and 5 considered optimal. Those with an optimal score reported sleeping 7 to 8 hours per night, never or rarely having insomnia, no frequent excessive daytime sleepiness, no sleep apnoea, and an early chronotype (being a morning person). The researchers checked for incident coronary heart disease and stroke every two years for a total of 10 years.

At baseline, 10% of participants had an optimal sleep score and 8% had a poor score. During a median follow up of eight years, 274 participants developed coronary heart disease or stroke. The researchers analysed the association between sleep scores and cardiovascular events after adjusting for age, sex, alcohol consumption, occupation, smoking, body mass index, physical activity, cholesterol level, diabetes, and family history of heart attack, stroke or sudden cardiac death. They found that the risk of coronary heart disease and stroke decreased by 22% for every 1 point rise in the sleep score at baseline. More specifically, compared to those with a score of 0 or 1, participants with a score of 5 had a 75% lower risk of heart disease or stroke.

The researchers estimated the proportion of cardiovascular events that could be prevented with healthier sleep. They found that if all participants had an optimal sleep score, 72% of new cases of coronary heart disease and stroke might be avoided each year.

Over two follow ups, almost half of participants (48%) changed their sleep score: in 25% it decreased whereas in 23% it improved. When the researchers examined the association between the change in score and cardiovascular events, they found that a 1 point increment over time was associated with a 7% reduction in the risk of coronary heart disease or stroke.

Dr. Nambiema said: "Our study illustrates the potential for sleeping well to preserve heart health and suggests that improving sleep is linked with lower risks of coronary heart disease and stroke. We also found that the vast majority of people have sleep difficulties. Given that cardiovascular disease is the top cause of death worldwide, greater awareness is needed on the importance of good sleep for maintaining a healthy heart."

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What makes the human brain different? Study reveals clues

What makes the human brain distinct from that of all other animals -- including even our closest primate relatives? In an analysis of cell types in the prefrontal cortex of four primate species, Yale researchers identified species-specific -- particularly human-specific -- features, they report Aug. 25 in the journal Science.

And they found that what makes us human may also makes us susceptible to neuropsychiatric diseases.

For the study, the researchers looked specifically at the dorsolateral prefrontal cortex (dlPFC), a brain region that is unique to primates and essential for higher-order cognition. Using a single cell RNA-sequencing technique, they profiled expression levels of genes in hundreds of thousands of cells collected from the dlPFC of adult humans, chimpanzees, macaque, and marmoset monkeys.

"Today, we view the dorsolateral prefrontal cortex as the core component of human identity, but still we don't know what makes this unique in humans and distinguishes us from other primate species." said Nenad Sestan, the Harvey and Kate Cushing Professor of Neuroscience at Yale, professor of comparative medicine, of genetics. and of psychiatry, and the lead senior author of the paper. "Now we have more clues."

To answer this, the researchers first asked whether there are there any cell types uniquely present in humans or other analyzed non-human primate species. After grouping cells with similar expression profiles they revealed 109 shared primate cell types but also five that were not common to all species. These included a type of microglia, or brain-specific immune cell, that was present only in humans and a second type shared by only humans and chimpanzees.

The human-specific microglia type exists throughout development and adulthood, the researchers found, suggesting the cells play a role in maintenance of the brain upkeep rather than combatting disease.

"We humans live in a very different environment with a unique lifestyle compared to other primate species; and glia cells, including microglia, are very sensitive to these differences," Sestan said. "The type of microglia found in the human brain might represent an immune response to the environment."

An analysis of gene expression in the microglia revealed another human-specific surprise -- the presence of the gene FOXP2. This discovery raised great interest because variants of FOXP2 have been linked to verbal dyspraxia, a condition in which patients have difficulty producing language or speech. Other studies have also shown that FOXP2 is associated with other neuropsychiatric diseases, such as autism, schizophrenia, and epilepsy.

Sestan and colleagues found that this gene exhibits primate-specific expression in a subset of excitatory neurons and human-specific expression in microglia.

"FOXP2 has intrigued many scientists for decades, but still we had no idea of what makes it unique in humans versus other primate species," said Shaojie Ma, a postdoctoral associate in Sestan's lab and co-lead author. We are extremely excited about the FOXP2 findings because they open new directions in the study of language and diseases."

Read more at Science Daily

NASA's Webb detects carbon dioxide in exoplanet atmosphere

NASA's James Webb Space Telescope has captured the first clear evidence for carbon dioxide in the atmosphere of a planet outside the solar system. This observation of a gas giant planet orbiting a Sun-like star 700 light-years away provides important insights into the composition and formation of the planet. The finding, accepted for publication in Nature, offers evidence that in the future Webb may be able to detect and measure carbon dioxide in the thinner atmospheres of smaller rocky planets.

WASP-39 b is a hot gas giant with a mass roughly one-quarter that of Jupiter (about the same as Saturn) and a diameter 1.3 times greater than Jupiter. Its extreme puffiness is related in part to its high temperature (about 1,600 degrees Fahrenheit or 900 degrees Celsius). Unlike the cooler, more compact gas giants in our solar system, WASP-39 b orbits very close to its star -- only about one-eighth the distance between the Sun and Mercury -- completing one circuit in just over four Earth-days. The planet's discovery, reported in 2011, was made based on ground-based detections of the subtle, periodic dimming of light from its host star as the planet transits, or passes in front of the star.

Previous observations from other telescopes, including NASA's Hubble and Spitzer space telescopes, revealed the presence of water vapor, sodium, and potassium in the planet's atmosphere. Webb's unmatched infrared sensitivity has now confirmed the presence of carbon dioxide on this planet as well.

Filtered Starlight

Transiting planets like WASP-39 b, whose orbits we observe edge-on rather than from above, can provide researchers with ideal opportunities to probe planetary atmospheres.

During a transit, some of the starlight is eclipsed by the planet completely (causing the overall dimming) and some is transmitted through the planet's atmosphere.

Because different gases absorb different combinations of colors, researchers can analyze small differences in brightness of the transmitted light across a spectrum of wavelengths to determine exactly what an atmosphere is made of. With its combination of inflated atmosphere and frequent transits, WASP-39 b is an ideal target for transmission spectroscopy.

First Clear Detection of Carbon Dioxide

The research team used Webb's Near-Infrared Spectrograph (NIRSpec) for its observations of WASP-39b. In the resulting spectrum of the exoplanet's atmosphere, a small hill between 4.1 and 4.6 microns presents the first clear, detailed evidence for carbon dioxide ever detected in a planet outside the solar system.

"As soon as the data appeared on my screen, the whopping carbon dioxide feature grabbed me," said Zafar Rustamkulov, a graduate student at Johns Hopkins University and member of the JWST Transiting Exoplanet Community Early Release Science team, which undertook this investigation. "It was a special moment, crossing an important threshold in exoplanet sciences."

No observatory has ever measured such subtle differences in brightness of so many individual colors across the 3 to 5.5-micron range in an exoplanet transmission spectrum before. Access to this part of the spectrum is crucial for measuring abundances of gases like water and methane, as well as carbon dioxide, which are thought to exist in many different types of exoplanets.

"Detecting such a clear signal of carbon dioxide on WASP-39 b bodes well for the detection of atmospheres on smaller, terrestrial-sized planets," said Natalie Batalha of the University of California at Santa Cruz, who leads the team.

Understanding the composition of a planet's atmosphere is important because it tells us something about the origin of the planet and how it evolved. "Carbon dioxide molecules are sensitive tracers of the story of planet formation," said Mike Line of Arizona State University, another member of this research team. "By measuring this carbon dioxide feature, we can determine how much solid versus how much gaseous material was used to form this gas giant planet. In the coming decade, JWST will make this measurement for a variety of planets, providing insight into the details of how planets form and the uniqueness of our own solar system."

Early Release Science

This NIRSpec prism observation of WASP-39 b is just one part of a larger investigation that includes observations of the planet using multiple Webb instruments, as well as observations of two other transiting planets. The investigation, which is part of the Early Release Science program, was designed to provide the exoplanet research community with robust Webb data as soon as possible.

"The goal is to analyze the Early Release Science observations quickly and develop open-source tools for the science community to use," explained Vivien Parmentier, a co-investigator from Oxford University. "This enables contributions from all over the world and ensures that the best possible science will come out of the coming decades of observations."

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30-million-year-old amphibious beaver fossil is oldest ever found

A new analysis of a beaver anklebone fossil found in Montana suggests the evolution of semi-aquatic beavers may have occurred at least 7 million years earlier than previously thought, and happened in North America rather than Eurasia.

In the study, Ohio State University evolutionary biologist Jonathan Calede describes the find as the oldest known amphibious beaver in the world and the oldest amphibious rodent in North America. He named the newly discovered species Microtheriomys articulaquaticus.

Calede's findings resulted from comparing measurements of the new species' anklebone to about 340 other rodent specimens to categorize how it moved around in its environment -- which indicated this animal was a swimmer. The Montana-based bone was determined to be 30 million years old -- the oldest previously identified semi-aquatic beaver lived in France 23 million years ago.

Beavers and other rodents can tell us a lot about mammalian evolution, said Calede, an assistant professor of evolution, ecology and organismal biology at Ohio State's Marion campus.

"Look at the diversity of life around us today, and you see gliding rodents like flying squirrels, rodents that hop like the kangaroo rat, aquatic species like muskrats, and burrowing animals like pocket gophers. There is an incredible diversity of shapes and ecologies. When that diversity arose is an important question," Calede said. "Rodents are the most diverse group of mammals on Earth, and about 4 in 10 species of mammals are rodents. If we want to understand how we get incredible biodiversity, rodents are a great system to study."

The research is published online today (Aug. 24, 2022) in the journal Royal Society Open Science.

The scientists, including Calede, who found the bones and teeth of the new beaver species in western Montana knew they came from beavers right away because of their recognizable teeth. But the discovery of an anklebone, about 10 millimeters long, opened up the possibility of learning much more about the animal's life. The astragalus bone in beavers is the equivalent to the talus in humans, located where the shin meets the top of the foot.

Calede took 15 measurements of the anklebone fossil and compared it to measurements -- over 5,100 in all -- of similar bones from 343 specimens of rodent species living today that burrow, glide, jump and swim as well as ancient beaver relatives.

Running computational analyses of the data in multiple ways, he arrived at a new hypothesis for the evolution of amphibious beavers, proposing that they started to swim as a result of exaptation -- the co-opting of an existing anatomy -- leading, in this case, to a new lifestyle.

"In this case, the adaptations to burrowing were co-opted to transition to a semi-aquatic locomotion," he said. "The ancestor of all beavers that have ever existed was most likely a burrower, and the semi-aquatic behavior of modern beavers evolved from a burrowing ecology. Beavers went from digging burrows to swimming in water.

"It's not necessarily surprising because movement through dirt or water requires similar adaptations in skeletons and muscles."

Fossils of fish and frogs and the nature of the rocks where Microtheriomys articulaquaticus fossils were found suggested it had been an aquatic environment, providing additional evidence to support the hypothesis, Calede said.

Fossils are usually dated based on their location between layers of rocks whose age is determined by the detection of the radioactive decay of elements left behind by volcanic activity. But in this case, Calede was able to age the specimen at a precise 29.92 million years old because of its location within, rather than above or below, a layer of ashes.

"The oldest semi-aquatic beaver we knew of in North America before this was 17 or 18 million years old," he said. "And the oldest aquatic beaver in the world, before this one, was from France and is about 23 million years old.

"I'm not claiming this new species is necessarily the oldest aquatic beaver ever, because there are other animals that we know, from their teeth, that are related to this species I described."

Microtheriomys articulaquaticus did not have the flat tail that helps beavers swim today. It likely ate plants instead of wood and was comparably small -- weighing less than 2 pounds. The modern adult beaver, weighing 50 pounds or so, is the second-largest living rodent after the capybara from South America.

Calede's analysis of beaver body size over the past 34 million years suggests beaver evolution adheres to what is known as Cope's Rule, which posits that organisms in evolving lineages increase in size over time. A giant beaver the size of a black bear lived in North America as recently as about 12,000 years ago. Like all but the two beaver species living today, Castor canadensis and Castor fiber, the giant beaver is extinct.

"It looks like when you follow Cope's Rule, it's not good for you -- it sets you on a bad path in terms of species diversity," Calede said. "We used to have dozens of species of beavers in the fossil record. Today we have one North American beaver and one Eurasian beaver. We've gone from a group that is super diverse and doing so well to one that is obviously not so diverse anymore."

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Social media experiment reveals potential to 'inoculate' millions of users against misinformation

Short animations giving viewers a taste of the tactics behind misinformation can help to "inoculate" people against harmful content on social media when deployed in YouTube's advert slot, according to a major online experiment led by the University of Cambridge.

Working with Jigsaw (https://jigsaw.google.com/), a unit within Google dedicated to tackling threats to open societies, a team of psychologists from the universities of Cambridge and Bristol created 90-second clips designed to familiarise users with manipulation techniques such as scapegoating and deliberate incoherence.

This "pre-bunking" strategy pre-emptively exposes people to tropes at the root of malicious propaganda, so they can better identify online falsehoods regardless of subject matter.

Researchers behind the Inoculation Science project (https://inoculation.science/) compare it to a vaccine: by giving people a "micro-dose" of misinformation in advance, it helps prevent them falling for it in future -- an idea based on what social psychologist's call "inoculation theory."

The findings, published in Science Advances, come from seven experiments involving a total of almost 30,000 participants -- including the first "real world field study" of inoculation theory on a social media platform -- and show a single viewing of a film clip increases awareness of misinformation.

The videos introduce concepts from the "misinformation playbook," illustrated with relatable examples from film and TV such as Family Guy or, in the case of false dichotomies, Star Wars ("Only a Sith deals in absolutes").

"YouTube has well over 2 billion active users worldwide. Our videos could easily be embedded within the ad space on YouTube to prebunk misinformation," said study co-author Prof Sander van der Linden, Head of the Social Decision-Making Lab (SDML) at Cambridge, which led the work.

"Our research provides the necessary proof of concept that the principle of psychological inoculation can readily be scaled across hundreds of millions of users worldwide."

Lead author Dr Jon Roozenbeek from Cambridge's SDML describes the team's videos as "source agnostic," avoiding biases people have about where information is from, and how it chimes -- or not -- with what they already believe.

"Our interventions make no claims about what is true or a fact, which is often disputed. They are effective for anyone who does not appreciate being manipulated," he said.

"The inoculation effect was consistent across liberals and conservatives. It worked for people with different levels of education, and different personality types. This is the basis of a general inoculation against misinformation."

Google -- YouTube's parent company -- is already harnessing the findings. At the end of August, Jigsaw will roll out a prebunking campaign across several platforms in Poland, Slovakia, and the Czech Republic to get ahead of emerging disinformation relating to Ukrainian refugees. The campaign is designed to build resilience to harmful anti-refugee narratives, in partnership with local NGOs, fact checkers, academics, and disinformation experts.

"Harmful misinformation takes many forms, but the manipulative tactics and narratives are often repeated and can therefore be predicted," said Beth Goldberg, co-author and Head of Research and Development for Google's Jigsaw unit.

"Teaching people about techniques like ad-hominem attacks that set out to manipulate them can help build resilience to believing and spreading misinformation in the future.

"We've shown that video ads as a delivery method of prebunking messages can be used to reach millions of people, potentially before harmful narratives take hold," Goldberg said.

The team argue that pre-bunking may be more effective at fighting the misinformation deluge than fact-checking each untruth after it spreads -- the classic 'debunk' -- which is impossible to do at scale, and can entrench conspiracy theories by feeling like personal attacks to those who believe them.

"Propaganda, lies and misdirections are nearly always created from the same playbook," said co-author Prof Stephan Lewandowsky from the University of Bristol. "We developed the videos by analysing the rhetoric of demagogues, who deal in scapegoating and false dichotomies."

"Fact-checkers can only rebut a fraction of the falsehoods circulating online. We need to teach people to recognise the misinformation playbook, so they understand when they are being misled."

Six initial controlled experiments featured 6,464 participants, with the sixth experiment conducted a year after the first five to ensure earlier findings could be replicated.

Data collection for each participant was comprehensive, from basic information -- gender, age, education, political leanings -- to levels of numeracy, conspiratorial thinking, news and social media checking, "bullshit receptivity," and a personality inventory, among other "variables."

Factoring all this in, the team found that inoculation videos improved people's ability to spot misinformation, and boosted their confidence in being able to do so again. The clips also improve the quality of "sharing decisions": whether or not to spread damaging content.

Two of the animations were then tested "in the wild" as part of a vast experiment on YouTube, with clips positioned in the pre-video advert slot that provides an option to skip after five seconds.

Google Jigsaw exposed around 5.4 million US YouTubers to an inoculation video, with almost a million watching for at least 30 seconds. The platform then gave a random 30% of users that watched a voluntary test question within 24 hours of their initial viewing.

The clips aimed to inoculate against misinformation tactics of hyper-emotive language and use of false dichotomies, and the questions -- based on fictional posts -- tested for detection of these tropes. YouTube also gave a "control" group of users who had not viewed a video the same test question. In total, 22,632 users answered a question.

Despite the intense "noise" and distractions on YouTube, ability to recognise manipulation techniques at the heart of misinformation increased by 5% on average.

Google say the unprecedented nature of the experiment means there is no direct data comparison available. However, increases in brand awareness from advertising on YouTube -- known as "brand lift" -- are typically limited to 1% in surveys of under 45,000 users.

"Users participated in tests around 18 hours on average after watching the videos, so the inoculation appears to have stuck," said van der Linden.

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Fossils of giant sea lizard that ruled the oceans 66 million years ago discovered

Researchers have discovered a huge new mosasaur from Morocco, named Thalassotitan atrox, which filled the apex predator niche. With massive jaws and teeth like those of killer whales, Thalassotitan hunted other marine reptiles -- plesiosaurs, sea turtles, and other mosasaurs.

At the end of the Cretaceous period, 66 million years ago, sea monsters really existed. While dinosaurs flourished on land, the seas were ruled by the mosasaurs, giant marine reptiles.

Mosasaurs weren't dinosaurs, but enormous marine lizards growing up to 12 metres (40 feet) in length. They were distant relatives of modern iguanas and monitor lizards.

Mosasaurs looked like a Komodo dragon with flippers instead of legs, and a shark-like tail fin. Mosasaurs became larger and more specialised in the last 25 million years of the Cretaceous, taking niches once filled by marine reptiles like plesiosaurs and ichthyosaurs. Some evolved to eat small prey like fish and squid. Others crushed ammonites and clams. The new mosasaur, named Thalassotitan atrox, evolved to prey on all the other marine reptiles.

The remains of the new species were dug up in Morocco, about an hour outside Casablanca. Here, near the end of the Cretaceous, the Atlantic flooded northern Africa. Nutrient rich waters upwelling from the depths fed blooms of plankton. Those fed small fish, feeding larger fish, which fed mosasaurs and plesiosaurs -- and so on, with these marine reptiles becoming food for the giant, carnivorous Thalassotitan.

Thalassotitan, had an enormous skull measuring 1.4 metres (5 feet long), and grew to nearly 30 feet (9 metres) long, the size of a killer whale. While most mosasaurs had long jaws and slender teeth for catching fish, Thalassotitan had a short, wide muzzle and massive, conical teeth like those of an orca. These let it seize and rip apart huge prey. These adaptations suggest Thalassotitan was an apex predator, sitting at the top of the food chain. The giant mosasaur occupied the same ecological niche as today's killer whales and great white sharks.

Thalassotitan's teeth are often broken and worn, however eating fish wouldn't have produced this sort of tooth wear. Instead, this suggests that the giant mosasaur attacked other marine reptiles, chipping, breaking, and grinding its teeth as it bit into their bones and tore them apart. Some teeth are so heavily damaged they have been almost ground down to the root.

Fossilised remains of prey

Remarkably, possible remains of Thalassotitan's victims have been discovered. Fossils from the same beds show damage from acids, with teeth and bone eaten away. Fossils with this peculiar damage include large predatory fish, a sea turtle, a half-meter long plesiosaur head, and jaws and skulls of at least three different mosasaur species. They would have been digested in Thalassotitan's stomach before it spat out their bones.

"It's circumstantial evidence," said Dr Nick Longrich, Senior Lecturer from the Milner Centre for Evolution at the University of Bath and lead author on the study, published in Cretaceous Research.

"We can't say for certain which species of animal ate all these other mosasaurs. But we have the bones of marine reptiles killed and eaten by a large predator.

"And in the same location, we find Thalassotitan, a species that fits the profile of the killer -- it's a mosasaur specialised to prey on other marine reptiles. That's probably not a coincidence."

Thalassotitan was a threat to everything in the oceans -- including other Thalassotitan. The huge mosasaurs bear injuries sustained in violent combat with other mosasaurs, with injuries to their face and jaws sustained in fights. Other mosasaurs show similar injuries, but in Thalassotitan these wounds were exceptionally common, suggesting frequent, intense fights over feeding grounds or mates.

"Thalassotitan was an amazing, terrifying animal," said Dr Nick Longrich, who led the study. "Imagine a Komodo Dragon crossed with a great white shark crossed with a T. rex crossed with a killer whale."

The new mosasaur lived in the final million years of the Age of Dinosaurs, a contemporary of animals like T. rex and Triceratops. Along with recent discoveries of mosasaurs from Morocco, it suggests that mosasaurs weren't in decline before the asteroid impact that drove the Cretaceous mass extinction. Instead, they flourished.

Professor Nour-Eddine Jalil, a co-author on the paper from the Museum of Natural History in Paris, said: "The phosphate fossils of Morocco offer an unparalleled window on the paleobiodiversity at the end of Cretaceous.

"They tell us how life was rich and diversified just before the end of the 'dinosaur era', where animals had to specialise to have a place in their ecosystems. Thalassotitan completes the picture by taking on the role of the megapredator at the top of the food chain."

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An extrasolar world covered in water?

An international team of researchers led by Charles Cadieux, a Ph.D. student at the Université de Montréal and member of the Institute for Research on Exoplanets (iREx), has announced the discovery of TOI-1452 b, an exoplanet orbiting one of two small stars in a binary system located in the Draco constellation about 100 light-years from Earth.

The exoplanet is slightly greater in size and mass than Earth and is located at a distance from its star where its temperature would be neither too hot nor too cold for liquid water to exist on its surface. The astronomers believe it could be an "ocean planet," a planet completely covered by a thick layer of water, similar to some of Jupiter's and Saturn's moons.

In an article published today in The Astronomical Journal, Cadieux and his team describe the observations that elucidated the nature and characteristics of this unique exoplanet.

"I'm extremely proud of this discovery because it shows the high calibre of our researchers and instrumentation," said René Doyon, Université de Montréal Professor and Director of iREx and of the Observatoire du Mont-Mégantic (OMM). "It is thanks to the OMM, a special instrument designed in our labs called SPIRou, and an innovative analytic method developed by our research team that we were able to detect this one-of-a-kind exoplanet."

It was NASA's space telescope TESS, which surveys the entire sky in search of planetary systems close to our own, that put the researchers on the trail of this exoplanet. Based on the TESS signal, which showed a slight decrease in brightness every 11 days, astronomers predicted a planet about 70% larger than Earth.

Charles Cadieux belongs to a group of astronomers that does ground follow-up observations of candidates identified by TESS in order to confirm their planet type and characteristics. He uses PESTO, a camera installed on the OMM's telescope that was developed by Université de Montréal Professor David Lafrenière and his Ph.D. student François-René Lachapelle.

"The OMM played a crucial role in confirming the nature of this signal and estimating the planet's radius," explained Cadieux. "This was no routine check. We had to make sure the signal detected by TESS was really caused by an exoplanet circling TOI-1452, the largest of the two stars in that binary system."

The host star TOI-1452 is much smaller than our Sun and is one of two stars of similar size in the binary system. The two stars orbit each other and are separated by such a small distance -- 97 astronomical units, or about two and a half times the distance between the Sun and Pluto -- that the TESS telescope sees them as a single point of light. But PESTO's resolution is high enough to distinguish the two objects, and the images showed that the exoplanet does orbit TOI-1452, which was confirmed through subsequent observations by a Japanese team.

Ingenuity at work

To determine the planet's mass, the researchers then observed the system with SPIRou, an instrument installed on the Canada-France-Hawaii Telescope in Hawai'i. Designed in large part in Canada, SPIRou is ideal for studying low-mass stars such as TOI-1452 because it operates in the infrared spectrum, where these stars are brightest. Even then, it took more than 50 hours of observation to estimate the planet's mass, which is believed to be nearly five times that of Earth.

Researchers Étienne Artigau and Neil Cook, also with iREx at the Université de Montréal, played a key role in analysing the data. They developed a powerful analytic method capable of detecting the planet in the data collected with SPIRou. "The LBL method [for line-by-line] allows us to clean the data obtained with SPIRou of many parasite signals and to reveal the weak signature of planets such as the one discovered by our team," explained Artigau.

The team also includes Quebec researchers Farbod Jahandar and Thomas Vandal, two Ph.D. students at the Université de Montréal. Jahandar analysed the host star's composition, which is useful for constraining the planet's internal structure, while Vandal was involved in analysing the data collected with SPIRou.

A watery world

The exoplanet TOI-1452 b is probably rocky like Earth, but its radius, mass, and density suggest a world very different from our own. Earth is essentially a very dry planet; even though we sometimes call it the Blue Planet because about 70% of its surface is covered by ocean, water actually only makes up a negligible fraction of its mass -- less than 1%.

Water may be much more abundant on some exoplanets. In recent years, astronomers have identified and determined the radius and mass of many exoplanets with a size between that of Earth and Neptune (about 3.8 times larger than Earth). Some of these planets have a density that can only be explained if a large fraction of their mass is made up of lighter materials than those that make up the internal structure of the Earth such as water. These hypothetical worlds have been dubbed "ocean planets."

"TOI-1452 b is one of the best candidates for an ocean planet that we have found to date," said Cadieux. "Its radius and mass suggest a much lower density than what one would expect for a planet that is basically made up of metal and rock, like Earth."

The University of Toronto's Mykhaylo Plotnykov and Diana Valencia are specialists in exoplanet interior modeling. Their analysis of TOI-1452 b shows that water may make up as much as 30% of its mass, a proportion similar to that of some natural satellites in our Solar System, such as Jupiter's moons Ganymede and Callisto, and Saturn's moons Titan and Enceladus.

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