Ancient bacteria might lurk beneath Mars' surface

When Mars' first samples return to Earth, scientists should be on the lookout for ancient sleeping bacteria, a new study has found.

In a first-of-its-kind study, a research team, including Northwestern University's Brian Hoffman and Ajay Sharma, found that ancient bacteria could survive close to the surface on Mars much longer than previously assumed. And -- when the bacteria are buried and, thus, shielded from galactic cosmic radiation and solar protons -- they can survive much longer.

These findings strengthen the possibility that if life ever evolved on Mars, its biological remains might be revealed in future missions, including ExoMars (Rosalind Franklin rover) and the Mars Life Explorer, which will carry drills to extract materials from 2 meters below the surface.

And because the scientists proved that certain strains of bacteria can survive despite Mars' harsh environment, future astronauts and space tourists could inadvertently contaminate Mars with their own hitchhiking bacteria.

The paper will be published on Tuesday (Oct. 25) in the journal Astrobiology.

"Our model organisms serve as proxies for both forward contamination of Mars, as well as backward contamination of Earth, both of which should be avoided," said Michael Daly, a professor of pathology at Uniformed Services University of the Health Sciences (USU) and member of the National Academies' Committee on Planetary Protection, who led the study. "Importantly, these findings have biodefense implications, too, because the threat of biological agents, such as Anthrax, remains a concern to military and homeland defense."

"We concluded that terrestrial contamination on Mars would essentially be permanent -- over timeframes of thousands of years," said Hoffman, a senior co-author of the study. "This could complicate scientific efforts to look for Martian life. Likewise, if microbes evolved on Mars, they could be capable of surviving until present day. That means returning Mars samples could contaminate Earth."

Hoffman is the Charles E. and Emma H. Morrison Professor of Chemistry and professor of molecular biosciences in Northwestern's Weinberg College of Arts and Sciences. He also is a member of the Chemistry of Life Processes Institute.

Simulating Mars

The environment on Mars is harsh and unforgiving. The arid and freezing conditions, which average -80 degrees Fahrenheit (-63 degrees Celsius) at mid-latitudes, make the Red Planet seem inhospitable to life. Even worse: Mars also is constantly bombarded by intense galactic cosmic radiation and solar protons.

To explore whether or not life could survive in these conditions, Daly, Hoffman and their collaborators first determined the ionizing radiation survival limits of microbial life. Then, they exposed six types of Earthling bacteria and fungi to a simulated Martian surface -- which is frozen and dry -- and zapped them with gamma rays or protons (to mimic radiation in space).

"There is no flowing water or significant water in the Martian atmosphere, so cells and spores would dry out," Hoffman said. "It also is known that the surface temperature on Mars is roughly similar to dry ice, so it is indeed deeply frozen."

Ultimately, the researchers determined that some terrestrial microorganisms potentially could survive on Mars over geologic timescales of hundreds of millions of years. In fact, the researchers discovered that one robust microbe, Deinococcus radiodurans (affectionately known as "Conan the Bacterium"), is particularly well-suited to surviving Mars' harsh conditions. In the novel experiments, Conan the Bacterium survived astronomical amounts of radiation in the freezing, arid environment -- far outlasting Bacillus spores, which can survive on Earth for millions of years.

Radical radiation

To test the effects of radiation, the team exposed samples to large doses of gamma radiation and protons -- typical to what Mars receives in the near subsurface -- and far smaller doses, which would occur if a microorganism was deeply buried.

Then, Hoffman's team at Northwestern used an advanced spectroscopy technique to measure the accumulation of manganese antioxidants in the radiated microorganisms' cells. According to Hoffman, the size of the radiation dose that a microorganism or its spores can survive correlates with the amount of manganese antioxidants it contains. Therefore, more manganese antioxidants means more resistance to radiation -- and more enhanced survival.

In earlier studies, previous researchers found that Conan the Bacterium, when suspended in liquid, can survive 25,000 units of radiation (or "grays"), the equivalent to about 1.2 million years just below Mars' surface. But the new study found that when the hearty bacterium is dried, frozen and deeply buried -- which would be typical to a Martian environment -- it could weather 140,000 grays of radiation. This dose is 28,000 times greater than what would kill a human.

Although Conan the Bacterium could only survive for a few hours at the surface while bathed in ultraviolet light, its lifetime improves dramatically when its shaded or located directly below Mars' surface. Buried just 10 centimeters below the Martian surface, Conan the Bacterium's survival period increases to 1.5 million years. And, when buried 10 meters down, the pumpkin-colored bacterium could survive a whopping 280 million years.

Looking to future missions

This astonishing survival feat is partially thanks to the bacterium's genomic structure, the researchers found. Long suspected, the researchers discovered that Conan the Bacterium's chromosomes and plasmids are linked together, keeping them in perfect alignment and ready for repair after intense radiation.

That means that if a microbe, similar to Conan the Bacterium, evolved during a time when water last flowed on Mars, then its living remains could still be dormant in the deep subsurface.

"Although D. radiodurans buried in the Martian subsurface could not survive dormant for the estimated 2 to 2.5 billion years since flowing water disappeared on Mars, such Martian environments are regularly altered and melted by meteorite impacts," Daly said. "We suggest that periodic melting could allow intermittent repopulation and dispersal. Also, if Martian life ever existed, even if viable lifeforms are not now present on Mars, their macromolecules and viruses would survive much, much longer. That strengthens the probability that, if life ever evolved on Mars, this will be revealed in future missions."

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Biblical military campaigns reconstructed using geomagnetic field data

A joint study by Tel-Aviv University and the Hebrew University, involving 20 researchers from different countries and disciplines, has accurately dated 21 destruction layers at 17 archaeological sites in Israel by reconstructing the direction and/or intensity of the Earth's magnetic field recorded in burnt remnants. The new data verify the Biblical accounts of the Egyptian, Aramean, Assyrian, and Babylonian military campaigns against the Kingdoms of Israel and Judah.

Findings indicate, for example, that the army of Hazael, King of Aram-Damascus, was responsible for the destruction of several cities -- Tel Rehov, Tel Zayit, and Horvat Tevet, in addition to Gath of the Philistines, whose destruction is noted in the Hebrew Bible. At the same time, the study refutes the prevailing theory that Hazael was the conqueror who destroyed Tel Beth-Shean. Other geomagnetic findings reveal that the cities in the Negev were destroyed by the Edomites, who took advantage of the destruction of Jerusalem and the Kingdom of Judah by the Babylonians.

The groundbreaking interdisciplinary study was published in the Proceedings of the National Academy of Sciences (PNAS) and is based on the doctoral thesis of Yoav Vaknin, supervised by Prof. Erez Ben-Yosef and Prof. Oded Lipschits of TAU's Institute of Archaeology and Prof. Ron Shaar from the Institute of Earth Sciences at the Hebrew University.

The researchers explain that geophysicists, attempting to understand the mechanism of earth's magnetic field, track changes in this field throughout history. To this end they use archaeological findings containing magnetic minerals which, when heated or burned, record the magnetic field at the time of the fire. Thus, in a 2020 study, researchers reconstructed the magnetic field as it was on the 9th of the month of Av, 586 BCE, the Hebrew date of the destruction of the First Temple and the City of Jerusalem by Nebuchadnezzar and his Babylonian army. Now, using archaeological findings unearthed over several decades at 17 sites throughout Israel, alongside historical information from ancient inscriptions and Biblical accounts, the researchers were able to reconstruct the magnetic fields recorded in 21 destruction layers. They used the data to develop a reliable new scientific tool for archaeological dating.

Yoav Vaknin explains: "Based on the similarity or difference in intensity and direction of the magnetic field, we can either corroborate or disprove hypotheses claiming that specific sites were burned during the same military campaign. Moreover, we have constructed a variation curve of field intensity over time which can serve as a scientific dating tool, similar to the radiocarbon dating method."

One example given by the researchers is the destruction of Gath of the Philistines (identified today as Tel Tzafit in the Judean foothills) by Hazael, King of Aram-Damascus. Various dating methods have placed this event at around 830 BCE, but were unable to verify that Hazael was also responsible for the destruction of Tel Rehov, Tel Zayit and Horvat Tevet. Now the new study, identifying full statistical synchronization between the magnetic fields recorded at all of these four sites at the time of destruction, makes a very strong case for their destruction during the same campaign. A destruction level at Tel Beth-Shean, on the other hand, recording a totally different magnetic field, refutes the prevailing hypothesis that it too was destroyed by Hazael. Instead, the magnetic data from Beth-Shean indicate that this city, along with two other sites in northern Israel, was probably destroyed 70-100 years earlier, a date which could correspond with the military campaign of the Egyptian Pharaoh Shoshenq. Shoshenq's campaign is described in the Hebrew Bible and in an inscription on a wall of the Temple of Amun in Karnak, Egypt, which mentions Beth-Shean as one of his conquests.

One of the most interesting findings revealed by the new dating method has to do with the end of the Kingdom of Judah. Prof. Erez Ben Yosef: "The last days of the Kingdom of Judah are widely debated. Some researchers, relying on archaeological evidence, argue that Judah was not completely destroyed by the Babylonians. While Jerusalem and frontier cities in the Judean foothills ceased to exist, other towns in the Negev, the southern Judean Mountains and the southern Judean foothills remained almost unaffected. Now, the magnetic results support this hypothesis, indicating that the Babylonians were not solely responsible for Judah's ultimate demise. Several decades after they had destroyed Jerusalem and the First Temple, sites in the Negev, which had survived the Babylonian campaign, were destroyed -- probably by the Edomites who took advantage of the fall of Jerusalem. This betrayal and participation in the destruction of the surviving cities may explain why the Hebrew Bible expresses so much hatred for the Edomites -- for example, in the prophecy of Obadiah."

Prof. Oded Lipschits adds: "The new dating tool is unique because it is based on geomagnetic data from sites, whose exact destruction dates are known from historical sources. By combining precise historical information with advanced, comprehensive archaeological research, we were able to base the magnetic method on reliably anchored chronology."

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Nestling birds recognize their local song 'dialect'

A recent study, published in Current Biology, led by researchers at Stockholm University and Uppsala University, has shown that juvenile songbirds react to hearing the songs they will eventually produce as adults, even when they are as young as 12 days old. Experiments conducted on nestling pied flycatchers across Europe demonstrate that they preferentially respond to songs from their own species and, remarkably, their own population.

Like human children learning language, juvenile songbirds learn their songs by listening to those produced by their parents and other adults. In both human language and songbird song, the learning process gives rise to small changes from one generation to the next, which leads to characteristic differences among populations, called dialects.

Broadcasted songs to nestlings

The study shows that pied flycatcher songs from 7 European populations form clearly defined dialects. By broadcasting songs to almost 2000 nestlings and observing their responses, the researchers demonstrate that young flycatchers respond to songs that are more similar to those from their own dialect by begging for food.

"These results establish that birds are 'tuned' from a young age to recognize their own populations' songs, which focuses subsequent learning," says David Wheatcroft, Associate Professor at the Department of Zoology, Stockholm University, who is the lead author of the study.

How are nestlings able to do this? One possibility is that nestling songbirds listen to their fathers' songs and thereby learn about the local dialect. However, 100s of hours of recordings at flycatcher nests at Stockholm University's Tovetorp Research Station revealed that nestlings hear extremely few songs, and, moreover, that nestlings whose fathers sing most often respond most weakly to the local dialect.

"An alternative is that nestlings recognize their own dialect innately," says David Wheatcroft.

Local dialect helps attract partners

He hopes these results will lead to future studies investigating how these dialect-specific responses develop and their consequences.

"If differences in early song responses among populations are truly innate, it would suggest a remarkable co-evolution between a cultural trait and the genes underlying it. Singing the local dialect is thought to help adults attract appropriate mates."

The researchers also found that dialect-specific responses may help prevent learning the songs of surrounding species. Pied flycatcher nestling responses to the songs of a closely related species, the collared flycatcher, were as weak as those to songs from other pied flycatcher dialects. Thus, the ability to discriminate against the songs of other species arises as a by-product of strong respondes to the local dialect.

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Vocal communication originated over 400 million years ago

The use of vocalizations as a resource for communication is common among several groups of vertebrates: singing birds, croacking frogs, or barking dogs are some well-known examples. These vocalizations play a fundamental role in parental care, mate attraction and various other behaviors. Despite its importance, little is known about when and at what stage in the evolutionary history of vertebrates this behavior first appeared. Comparative analyses can provide insights into the evolutionary origin of acoustic communication, but they are often plagued by missing information from key groups that have not been broadly studied.

Acoustic abilities are widespread in land vertebrates

An international research team led by the University of Zurich (UZH) has therefore focused on species that have never been accessed before. Their study includes evidence for 53 species of four major clades of land vertebrates -- turtles, tuataras, caecilians and lungfishes -- in the form of vocal recordings and contextual behavioral information accompanying sound production. "This, along with a broad literature-based dataset including 1800 different species covering the entire spectrum shows that vocal communication is not only widespread in land vertebrates, but also evidence acoustic abilities in several groups previously considered non-vocal," says first author Gabriel Jorgewich-Cohen, PhD student at the Paleontological Institute and Museum of UZH. Many turtles, for example, which were thought to be mute are in fact showing broad and complex acoustic repertoires.

Last common ancestor lived about 407 million years ago

To investigate the evolutionary origins of acoustic communication in vertebrates, the researchers combined relevant data on the vocalization abilities of species like lizards, snakes, salamanders, amphibians, and dipnoi with phylogenetic trait reconstruction methods. Combined with data of well-known acoustic clades like mammals, birds, and frogs, the researchers were able to map vocal communication in the vertebrate tree of life. "We were able to reconstruct acoustic communication as a shared trait among these animals, which is at least as old as their last common ancestor that lived approximately 407 million years before present," explains Marcelo Sánchez, who led the study.

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The environmental footprint of food

In an age of industrialized farming and complex supply chains, the true environmental pressures of our global food system are often obscure and difficult to assess.

"Everyone eats food, and more and more people are paying attention to the planetary consequences of what they eat," said UC Santa Barbara marine ecologist Ben Halpern. Figuring out this impact to the planet proves to be a gargantuan task for many reasons, including the fact that around the world there are a lot of different foods produced in many different ways, with many different environmental pressures.

By ranking foods on factors such as greenhouse gas emissions or water pollution, scientists have made useful headway on assessments of the environmental impacts of food by pound or kilogram. While these evaluations are helpful in guiding consumer choices, Halpern explained that a more comprehensive examination of the environmental footprint -- the locations affected by the various pressures from food production and the severity of that pressure -- is needed for decisions that have to be made in a world with a booming population.

"The individual choice of eight billion people adds up," he said, "and we need to know the overall impact of total food production -- not just per pound -- especially when setting food policy."

To fill that need, Halpern and colleagues at UC Santa Barbara's National Center for Ecological Analysis & Synthesis (NCEAS) have mapped for the first time the environmental footprint of the production of all foods, both in the ocean and on land. Their research is published in the journal Nature Sustainability.

Lopsided pressures and hidden connections

"Did you know that almost half of all environmental pressures from food production come from just five countries?" Halpern said.

For Halpern, executive director at NCEAS and a professor at UCSB's Bren School of Environmental Science & Management, understanding the impacts of food production along with the local context of these impacts has been a longstanding interest. By taking detailed data about greenhouse gas emissions, freshwater use, habitat disturbance and nutrient pollution (e.g., fertilizer runoff) generated by 99% of total reported production of aquatic and terrestrial foods in 2017, and mapping those impacts at high resolution, the researchers were able to create a more nuanced picture of the pressures -- the inputs, processes and outputs -- of global food production.

The findings are eye-opening.

"Cumulative pressures of food production are more concentrated than previously believed, with the vast majority -- 92% of pressures from land-based food production -- concentrated on just 10% of the Earth's surface," noted Melanie Frazier, a research scientist at NCEAS and coauthor of the paper. Additionally, the space required for dairy and beef farming accounts for about a quarter of the cumulative footprint of all food production. And those five countries accounting for almost half of all food production-related environmental pressures? India, China, the United States, Brazil and Pakistan.

The study also examines the environmental efficiency of each food type, similar to the per-pound of food approach that most other studies use, but now accounting for differences among countries rather than just assuming it is the same everywhere.

"The environmental efficiency of producing a particular food type varies spatially, such that rankings of foods by efficiency differ sharply among countries, and this matters for guiding which foods we eat and from where," said Halley Froehlich, assistant professor in environmental studies at UCSB and a coauthor of the study.

Methods of production factor into the research team's assessment. For instance, thanks to technology that reduces greenhouse gases and increases yields, the United States -- the world's number one producer of soy -- is more than twice as efficient as India (the fifth largest producer) at producing the crop, making American soy the more environmentally friendly choice.

The research also uncovers connections between land and sea that get missed when looking only at one or the other, and that result in significant environmental pressures. Pigs and chicken have an ocean footprint because marine forage fish such as herrings, anchovies and sardines are used for their feed. The converse is true for mariculture farms, whose crop-based feeds extend the fish farms' environmental pressure on to land.

Assessing cumulative pressures can bring to light results that could not have been predicted by examining individual pressures alone. For instance, while raising cattle requires by far the most grazing land, the cumulative pressures of pig farming, which produces a lot of pollution and uses more water than cattle farming, are slightly greater than that of cows. Measured by cumulative pressures, the top five offenders are pig, cow, rice, wheat and oil crops.

In order to feed a growing and increasingly wealthy global population while reducing environmental degradation and enhancing food security, major shifts will need to be made to current food systems, according to the researchers. In some cases, farming might need to improve efficiency; in other cases, consumers might need to change their food choices.

"We need this comprehensive information to make more accurate decisions about what we eat," said Halpern, who modified his own food choices based on the results of this study.

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Skaftö wreck's cargo tells a tale of 15th century trade routes

Research at the University of Gothenburg has shown that the Skaftö wreck had probably taken on cargo in Gdańsk in Poland and was heading towards Belgium when it foundered in the Lysekil archipelago around 1440. Modern methods of analysis of the cargo are now providing completely new answers about the way trade was conducted in the Middle Ages.

"The analyses we have carried out give us a very detailed picture of the ship's last journey and also tell us about the geographical origins of its cargo. Much of this is completely new knowledge for us," says Staffan von Arbin, a maritime archaeologist.

For example, it was not previously known that calcium oxide (CaO), commonly known as quicklime or burnt lime, was exported from Gotland in the 15th century.

In 2003, the Skaftö wreck was found at the bottom of the sea off Lysekil, north of Gothenburg. But it is only now that researchers have been able to carry out analyses of its cargo using new, modern methods.

An international research team, headed by maritime archaeologist Staffan von Arbin at the University of Gothenburg, has succeeded in mapping the origins of its cargo and the probable route of the ship. The study contributes new knowledge about the goods traded in the Middle Ages and the trade routes in that period.

The cargo included copper, oak timber, quicklime, tar, and bricks and roof tiles. Samples of the cargo have been taken up from the wreck during previous underwater archaeological investigations carried out by the Bohusläns museum. But it's only now that analyses of its cargo have been possible using modern analysis methods.

From Gotland in Sweden

With these analyses, the researchers have been able to establish that the copper was mined in two areas in what is currently Slovakia, for example. The analyses also show that the bricks, timber and probably also the tar originated in Poland, while the quicklime is apparently from Gotland.

According to medieval sources, copper was transported from the Slovakian mining districts in the Carpathian Mountains via river systems down to the coastal town of Gdańsk (Danzig) in Poland. In the Middle Ages, Gdańsk was also the dominant port for exporting Polish oak timber.

"It is therefore very likely that it was in Gdańsk that the ship took on its cargo before it continued on what would be its final voyage."

Heading for Belgium

The composition of the cargo indicates that the ship was on its way to a western European port when, for unknown reasons, it foundered in the Bohuslän archipelago. Here, too, the research team have drawn conclusions from historical sources.

"We believe that the ship's final destination was Bruges in Belgium. In the 15th century, this city was a major trading hub. We also know that copper produced in Central Europe was shipped on from there to various Mediterranean ports, including Venice."

The study presents the recent investigations of the composition of the cargo. These results were then compared with other sources from the same period, archaeological as well as historical. The study has been published in the article Tracing Trade Routes: Examining the Cargo of the 15th-Century Skaftö Wreck, in the International Journal of Nautical Archaeology.

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UK's oldest human DNA obtained, revealing two distinct Palaeolithic populations

The first genetic data from Palaeolithic human individuals in the UK -- the oldest human DNA obtained from the British Isles so far -- indicates the presence of two distinct groups that migrated to Britain at the end of the last ice age, according to new research.

Published today in Nature Ecology and Evolution, the new study by UCL Institute of Archaeology, the Natural History Museum and the Francis Crick Institute researchers reveals for the first time that the recolonisation of Britain consisted of at least two groups with distinct origins and cultures.

The study team explored DNA evidence from an individual from Gough's Cave, Somerset, and an individual from Kendrick's Cave, North Wales, who both lived more than 13,500 years ago. Very few skeletons of this age exist in Britain, with around a dozen found across six sites in total. The study, which involved radiocarbon dating and analysis as well as DNA extraction and sequencing, shows that it is possible to obtain useful genetic information from some of the oldest human skeletal material in the country.

The authors say that these genome sequences now represent the earliest chapter of the genetic history of Britain, but ancient DNA and proteins promise to take us back even further into human history.

The researchers found that the DNA from the individual from Gough's Cave, who died about 15,000 years ago, indicates that her ancestors were part of an initial migration into northwest Europe around 16,000 years ago. However, the individual from Kendrick's Cave is from a later period, around 13,500 years ago, with his ancestry from a western hunter-gatherer group. This group's ancestral origins are thought to be from the near East, migrating to Britain around 14,000 years ago.

Study co-author Dr Mateja Hajdinjak (Francis Crick Institute) said: "Finding the two ancestries so close in time in Britain, only a millennium or so apart, is adding to the emerging picture of Palaeolithic Europe, which is one of a changing and dynamic population."

The authors note that these migrations occurred after the last ice age when approximately two-thirds of Britain was covered by glaciers. As the climate warmed and the glaciers melted, drastic ecological and environmental changes took place and humans began to move back into northern Europe.

Study co-author Dr Sophy Charlton, who undertook the study whilst at the Natural History Museum, said: "The period we were interested in, from 20-10,000 years ago, is part of the Palaeolithic -- the Old Stone Age. This is an important time period for the environment in Britain, as there would have been significant climate warming, increases in the amount of forest, and changes in the type of animals available to hunt."

As well as genetically, the two groups were found to be culturally distinct, with differences in what they ate and how they buried their dead.

Study co-author Dr Rhiannon Stevens (UCL Institute of Archaeology) said: "Chemical analyses of the bones showed that the individuals from Kendrick's Cave ate a lot of marine and freshwater foods, including large marine mammals.

"Humans at Gough's Cave, however, showed no evidence of eating marine and freshwater foods, and primarily ate terrestrial herbivores such as red deer, bovids (such as wild cattle called aurochs) and horses."

The researchers discovered that the mortuary practices of the two groups also differed. Although there were animal bones found at Kendrick's Cave, these included portable art items, such as a decorated horse jawbone. No animal bones were found that showed evidence of being eaten by humans, and the scientists say that this indicates the cave was used as a burial site by its occupiers.

In contrast, animal and human bones found in Gough's Cave showed significant human modification, including human skulls modified into 'skull-cups', which the researchers believe to be evidence for ritualistic cannibalism. Individuals from this earlier population seem to be the same people who created the Magdalenian stone tools, a culture known also for iconic cave art and bone artefacts.

Gough's Cave is also the site where Britain's famous Cheddar Man was discovered in 1903, dated to 10,564-9,915 years BP. In this study, Cheddar Man was found to have a mixture of ancestries, mostly (85%) western hunter-gatherer and some (15%) of the older type from the initial migration.

Co-author Dr Selina Brace (Natural History Museum) said: "We really wanted to find out more about who these early populations in Britain might have been.

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Video gaming may be associated with better cognitive performance in children, study suggests

A study of nearly 2,000 children found that those who reported playing video games for three hours per day or more performed better on cognitive skills tests involving impulse control and working memory compared to children who had never played video games. Published today in JAMA Network Open, this study analyzed data from the ongoing Adolescent Brain Cognitive Development (ABCD) Study, which is supported by the National Institute on Drug Abuse (NIDA) and other entities of the National Institutes of Health.

"This study adds to our growing understanding of the associations between playing video games and brain development," said NIDA Director Nora Volkow, M.D. "Numerous studies have linked video gaming to behavior and mental health problems. This study suggests that there may also be cognitive benefits associated with this popular pastime, which are worthy of further investigation."

Although a number of studies have investigated the relationship between video gaming and cognitive behavior, the neurobiological mechanisms underlying the associations are not well understood. Only a handful of neuroimaging studies have addressed this topic, and the sample sizes for those studies have been small, with fewer than 80 participants.

To address this research gap, scientists at the University of Vermont, Burlington, analyzed data obtained when children entered the ABCD Study at ages 9 and 10 years old. The research team examined survey, cognitive, and brain imaging data from nearly 2,000 participants from within the bigger study cohort. They separated these children into two groups, those who reported playing no video games at all and those who reported playing video games for three hours per day or more. This threshold was selected as it exceeds the American Academy of Pediatrics screen time guidelines, which recommend that videogaming time be limited to one to two hours per day for older children. For each group, the investigators evaluated the children's performance on two tasks that reflected their ability to control impulsive behavior and to memorize information, as well as the children's brain activity while performing the tasks.

The researchers found that the children who reported playing video games for three or more hours per day were faster and more accurate on both cognitive tasks than those who never played. They also observed that the differences in cognitive function observed between the two groups was accompanied by differences in brain activity. Functional MRI brain imaging analyses found that children who played video games for three or more hours per day showed higher brain activity in regions of the brain associated with attention and memory than did those who never played. At the same time, those children who played at least three hours of videogames per day showed more brain activity in frontal brain regions that are associated with more cognitively demanding tasks and less brain activity in brain regions related to vision.

The researchers think these patterns may stem from practicing tasks related to impulse control and memory while playing videogames, which can be cognitively demanding, and that these changes may lead to improved performance on related tasks. Furthermore, the comparatively low activity in visual areas among children who reported playing video games may reflect that this area of the brain may become more efficient at visual processing as a result of repeated practice through video games.

While prior studies have reported associations between video gaming and increases in depression, violence, and aggressive behavior, this study did not find that to be the case. Though children who reported playing video games for three or more hours per day did tend to report higher mental health and behavioral issues compared to children who played no video games, the researchers found that this association was not statistically significant, meaning that the authors could not rule out whether this trend reflected a true association or chance. They note that this will be an important measure to continue to track and understand as the children mature.

Further, the researchers stress that this cross-sectional study does not allow for cause-and-effect analyses, and that it could be that children who are good at these types of cognitive tasks may choose to play video games. The authors also emphasize that their findings do not mean that children should spend unlimited time on their computers, mobile phones, or TVs, and that the outcomes likely depend largely on the specific activities children engage in. For instance, they hypothesize that the specific genre of video games, such as action-adventure, puzzle solving, sports, or shooting games, may have different effects for neurocognitive development, and this level of specificity on the type of video game played was not assessed by the study.

"While we cannot say whether playing video games regularly caused superior neurocognitive performance, it is an encouraging finding, and one that we must continue to investigate in these children as they transition into adolescence and young adulthood," said Bader Chaarani, Ph.D., assistant professor of psychiatry at the University of Vermont and the lead author on the study. "Many parents today are concerned about the effects of video games on their children's health and development, and as these games continue to proliferate among young people, it is crucial that we better understand both the positive and negative impact that such games may have."

Through the ABCD Study, researchers will be able to conduct similar analyses for the same children over time into early adulthood, to see if changes in video gaming behavior are linked to changes in cognitive skills, brain activity, behavior, and mental health. The longitudinal study design and comprehensive data set will also enable them to better account for various other factors in the children's families and environment that may influence their cognitive and behavioral development, such as exercise, sleep quality, and other influences.

The ABCD Study, the largest of its kind in the United States, is tracking nearly 12,000 youth as they grow into young adults. Investigators regularly measure participants' brain structure and activity using magnetic resonance imaging (MRI) and collect psychological, environmental, and cognitive information, as well as biological samples. The goal of the study is to understand the factors that influence brain, cognitive, and social-emotional development, to inform the development of interventions to enhance a young person's life trajectory.

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Looking to move to a galaxy far, far away? Innovative system evaluates habitability of distant planets

The climate crisis presents a huge challenge to all people on Earth. It has led many scientists to look for exoplanets, planets outside our solar system that humans could potentially settle.

The James Webb Space Telescope was developed as part of this search to provide detailed observational data about Earth-like exoplanets in the coming years. A new project, led by Dr. Assaf Hochman at the Fredy & Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem (HU), in collaboration with Dr. Paolo De Luca at the Barcelona Supercomputing Center and Dr. Thaddeus D. Komacek at the University of Maryland, has successfully developed a framework to study the atmospheres of distant planets and locate those planets fit for human habitation, without having to visit them physically. Their joint research study was published in the Astrophysical Journal.

Classifying climate conditions and measuring climate sensitivity are central elements when assessing the viability of exoplanets as potential candidates for human habitation. In the current study, the research team examined TRAPPIST-1e, a planet located some 40 light years from the Earth and scheduled to be documented by the James Webb Space Telescope in the coming year. The researchers looked at the sensitivity of the planet's climate to increases in greenhouse gases and compared it with conditions on Earth. Using a computerized simulation of the climate on TRAPPIST-1e, they could assess the impact of changes in greenhouse gas concentration.

The study focused on the effect of an increase in carbon dioxide on extreme weather conditions, and on the rate of changes in weather on the planet. "These two variables are crucial for the existence of life on other planets, and they are now being studied in depth for the first time in history," explained Hochman.

According to the research team, studying the climate variability of earth-like exoplanets provides a better understanding of the climate changes we are currently experiencing on Earth. Additionally, this kind of research offers a new understanding of how planet Earth's atmosphere might change in the future.

Hochman and his research partners found that planet TRAPPIST-1e has a significantly more sensitive atmosphere than planet Earth. They estimate that an increase in greenhouse gases there could lead to more extreme climate changes than we would experience here on Earth because one side of TRAPPIST-1e constantly faces its own sun, in the same way, that our moon always has one side facing the Earth.

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Secrets of Namibia's fairy circles demystified: Plants self-organize

Scientists have puzzled over the origin of Namibia's fairy circles for nearly half a century. It boiled down to two main theories: either termites were responsible, or plants were somehow self-organizing. Now, researchers from the University of Göttingen, benefitting from two exceptionally good rainfall seasons in the Namib Desert, show that the grasses within the fairy circles died immediately after rainfall, but termite activity did not cause the bare patches. Instead, continuous soil-moisture measurements demonstrate that the grasses around the circles strongly depleted the water within the circles and thereby likely induced the death of the grasses inside the circles. The results were published in Perspectives in Plant Ecology, Evolution and Systematics.

About 80-140 kilometres from the coast in the Namib, there are millions of fairy circles -- circular gaps in the grassland, each a few meters wide, together forming a distinctive pattern across the whole landscape and visible for miles around. The researchers followed the sporadic rain events in several regions in this desert and examined the grasses, their roots and shoots, and potential root damage induced by termites. Termites, tiny insects that live in large colonies around the world, have often been blamed for the death of the grasses. The researchers took great care to investigate the circumstances of dying grasses within fairy circles right from straight after the rainfall, which triggered the new growth of the grasses. Additionally, they installed soil-moisture sensors in and around the fairy circles to record the soil-water content at 30-minute intervals starting in the dry season 2020 to the end of the rainy season 2022. This enabled the researchers to record precisely how the growth of the new emerging grasses around the circles affected the soil water within and around the circles. They investigated the differences in water infiltration between the inside and outside of circles at ten regions across the Namib.

The data show that about ten days after rainfall, the grasses were already starting to die within the circles while most of the interior area of the circles did not have grass germination at all. Twenty days after rainfall, the struggling grasses within the circles were completely dead and yellowish in colour while the surrounding grasses were vital and green. When the researchers examined the roots of the grasses from within the circles and compared them to the green grasses on the outside, they found that the roots within the circles were as long as, or even longer than, those outside. This indicated that the grasses were putting effort into the growth of roots in search of water. However, the researchers found no evidence for termites feeding on roots. It was not until fifty to sixty days after the rainfall that root damage became more visible at the dead grasses. Dr Stephan Getzin, Department of Ecosystem Modelling at the University of Göttingen, explains: "The sudden absence of grass for most areas within the circles cannot be explained by the activity of termites because there was no biomass for these insects to feed on. But more importantly, we can show that the termites are not responsible because the grasses die immediately after rainfall without any sign of creatures feeding on the root."

When the researchers analyzed the data on soil-moisture fluctuations, they found that the decline in soil water inside and outside of the circles was very slow after initial rainfall, when grasses were not yet established. However, when the surrounding grasses were well established, the decline in soil water after rainfall was very fast in all areas, even though there were almost no grasses within the circles to take the water. Getzin explains: "Under the strong heat in the Namib, the grasses are permanently transpiring and losing water. Hence, they create soil-moisture vacuums around their roots and water is drawn towards them. Our results strongly agree with those of researchers who have shown that water in soil diffuses quickly and horizontally in these sands even over distances greater than seven meters."

Getzin adds: "By forming strongly patterned landscapes of evenly spaced fairy circles, the grasses act as ecosystem engineers and benefit directly from the water resource provided by the vegetation gaps. In fact, we know related self-organized vegetation structures from various other harsh drylands in the world, and in all those cases the plants have no other chance to survive except by growing exactly in such geometrical formations." This research has implications for understanding similar ecosystems, especially with regard to climate change, because the self-organization of plants buffers against negative effects induced by increasing aridification.

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