Agriculture linked to changes in age-independent mortality in North America

The transition to agriculture from hunting and gathering in pre-colonial North America led to changes in age-independent mortality, or mortality caused by factors that are not associated with age, according to a new study by a Penn State-led research team. The team found that the intensification of crop use occurred in two phases, the first of which led to a decline in human age-independent mortality, while the second is associated with a rise in it. The study is the first to tie patterns of age-independent mortality to food production.

"This study tells the story of our shared human experience," said George Milner, distinguished professor of anthropology at Penn State and lead author. "We have several examples around the world where we see a move toward crop domestication as an independent event -- eastern North America, particularly the midcontinent, being one of them, but so too the Fertile Crescent in the Middle East. Also, there are demographic changes happening. This paper addresses the relationship between the move toward agriculture and demographic change."

The researchers examined previously published data to identify general trends in archaeobotanical samples, or the remains of plants in the archaeological record, and skeletal samples from sites across eight states stretching from Illinois to northern Alabama. They wanted to study the relationship between the domestication of crops and an index that uses skeletal data to capture the frequency of juveniles aged five to 19 years old relative to all individuals aged five or more. Anthropologists normally use the index to measure fertility rates and population growth, but the new work shows it is more responsive to age-independent mortality.

Mortality models, including those for pre-industrial societies, contain three components: juvenile mortality, which declines as children get older; adult mortality, where the probability of dying increases with advancing age; and age-independent mortality, an equal probability of dying for members of all age groups, which might occur in extreme events like food shortages, epidemics or warfare.

The researchers studied the archaeobotanical data to identify where the record showed an increase in the consumption of domesticated crops compared to foraged foods like nuts. They also examined skeletal data to identify decreases or increases in the indicator of age-independent mortality. The index focuses on individuals between five and 19 years old because in human populations that age range is characterized by low mortality relative to other age groups. Increases in mortality for this age group would indicate the occurrence of events like famines or conflict.

The researchers identified a strong correlation between crop domestication and changing age-independent mortality rates. Crop domestication happened in two stages in pre-colonial North America, with a decrease in age-independent mortality noted during the first stage of crop domestication and a rise during the second stage. The researchers reported their findings in the Proceedings of the National Academy of Sciences.

"What we've found is the index that has traditionally been interpreted as a fertility and population growth indicator is more tightly correlated to age-independent mortality, which reflects the number of deaths in the part of the age distribution where very few people die," said Milner. "This means that the pattern of first adoption of agriculture, seen elsewhere in the world and observed in eastern North America as well, coincides with lower age-independent mortality. Basically, it's good times, and that's what we see culturally."

The first stage of agricultural intensification in North America, which includes the cultivation of plants such as squash, sunflower and other native plants, occurred approximately 2,000 years ago during the Middle Woodland period up to about A.D. 500, said Milner. Indigenous societies flourished during this time. They established long-distance exchange networks, had an incredibly rich ceremonial life, and constructed big mounds and earthwork complexes.

The archaeological record shows that in the centuries just before A.D. 1000, and from that time onward, there was an increase in warfare. During this time Indigenous societies began cultivating maize and beans, and a number of new cultural changes occurred, including the initial development of powerful chiefdom societies. Age-independent mortality increased during this period, presumably due to conflict and the spread of diseases from higher numbers of individuals living near one another.

"The overall pattern seen in the demographic picture of North American pre-European contact is similar to other datasets from around the world," Milner said. "The entire story makes perfect sense in terms of agricultural productivity, demographic change and cultural developments, including change over time in conflict and sociopolitical systems."

The study links, for the first time, a worldwide pattern to age-independent mortality and agricultural developments, according to Milner.

Read more at Science Daily

Young chimpanzees and human teens share risk-taking behaviors

Adolescent chimpanzees share some of the same risk-taking behaviors as human teens, but they may be less impulsive than their human counterparts, according to research published by the American Psychological Association. The study gets at age-old nature/nurture questions about why adolescents take more risks: because of environment or because of biological predispositions?

"Adolescent chimpanzees are in some sense facing the same psychological tempest that human teens are," said lead researcher Alexandra Rosati, PhD, an associate professor of psychology and anthropology at the University of Michigan. "Our findings show that several key features of human adolescent psychology are also seen in our closest primate relatives."

The researchers conducted two tests involving food rewards with 40 wild-born chimpanzees at a sanctuary in Republic of Congo. The chimpanzees voluntarily participated in the games in order to receive food treats. The research was published online in the Journal of Experimental Psychology: General.

Chimpanzees can live to be 50 years old and experience adolescence at about 8 to 15. Like humans, chimpanzees show rapid changes in hormone levels during adolescence, start forming new bonds with peers, show increases in aggression and compete for social status.

In the first test, adolescent and adult chimpanzees could choose between two containers in a gambling task. One container always contained peanuts, a food that chimpanzees somewhat like. The other container concealed either an unliked food -- a cucumber slice -- or a favorite food -- a banana slice. The chimpanzees could play it safe and get the peanuts, or take a chance for some coveted banana at the risk of ending up with unappetizing cucumber.

The chimpanzees' emotional reactions and vocalizations were recorded, including moans, whimpers, screams, banging on the table or scratching themselves. Saliva samples also were collected to track hormone levels.

During several rounds of the test, adolescent chimpanzees took the risky option more often than adult chimpanzees, but adolescents and adults had similar negative reactions when they received cucumber.

The second test, modeled after the famous "marshmallow test" with human children, examined delayed gratification where chimpanzees could receive one banana slice immediately or wait for one minute to receive three slices.

Both adolescent and adult chimpanzees chose the greater delayed reward at a similar rate. Human teens tend to be more impulsive than adults so they would be more likely to take the immediate reward.

"Prior research indicates that chimpanzees are quite patient compared with other animals, and our study shows that their ability to delay gratification is already mature at a fairly young age, unlike in humans," Rosati said.

However, adolescent chimpanzees weren't happy about waiting for the extra banana slices and they threw more tantrums during the one-minute delay than adult chimpanzees.

Read more at Science Daily

Genome editing procedures optimized

In the course of optimising key procedures of genome editing, researchers from the department of Developmental Biology / Physiology at the Centre for Organismal Studies of Heidelberg University have succeeded in substantially improving the efficiency of molecular genetic methods such as CRISPR/Cas9 and related systems, and in broadening their areas of application. Together with colleagues from other disciplines, the life scientists fine-tuned these tools to enable, inter alia, effective genetic screening for modelling specific gene mutations. In addition, initially inaccessible DNA sequences can now be modified. According to Prof. Dr Joachim Wittbrodt, this opens up extensive new areas of work in basic research and, potentially, therapeutic application.

Genome editing means the deliberate altering of DNA with molecular genetic methods. It is used to breed plants and animals, but also in basic medical and biological research. The most common procedures include the "gene scissors" CRISPR/Cas9 and its variants known as base editors. In both cases, enzymes have to be transported into the nucleus of the target cell. Upon arrival, the CRISPR/Cas9 system cuts the DNA at specific sites, which causes a double strand break. New DNA segments can then be inserted at that site. Base editors use a similar molecular mechanism but they do not cut the DNA double strand. Instead, an enzyme coupled with the Cas9 protein performs a targeted exchange of nucleotides -- the basic building blocks of the genome. In three successive studies, Prof. Wittbrodt's team succeeded in considerably enhancing the efficiency and applicability of these methods.

A challenge when using CRISPR/Cas9 consists in the efficient delivery of the required Cas9 enzymes to the nucleus. "The cell has an elaborate 'bouncer' mechanism. It distinguishes between proteins that are allowed to translocate into the nucleus and those that are supposed to stay in the cytoplasm," explains Dr Tinatini Tavhelidse-Suck from Prof. Wittbrodt's team. Access is enabled here by a tag made up of a few amino acids that functions like an "admission ticket." The scientists have now come up with a kind of generally valid "VIP admission ticket" which lets enzymes equipped with it into the nucleus very quickly. They have named it "high efficiency-tag," "hei-tag" for short. "Other proteins that have to penetrate the cell nucleus are also more successful with 'hei-tag'," concludes Dr Thomas Thumberger, who is also a researcher at the Centre for Organismal Studies (COS). In cooperation with pharmacologists from Heidelberg University, the team could show that Cas9 in connection with the "hei-tag" ticket can enable highly efficient, targeted genome alterations not only in the model organism medaka, the Japanese ricefish (Oryzias latipes), but also in mammalian cell cultures and mouse embryos.

In a further study, the Heidelberg scientists showed that base editors operate highly efficiently in the living organism and are even suited to genetic screening. In an experiment with Japanese rice fish, they were able to show that these locally limited, targeted modifications in individual buildings blocks of the DNA achieve an outcome that is otherwise only obtained by the comparatively laborious breeding of organisms with altered genes. The research team at COS, in cooperation with Dr Dr Jakob Gierten, a paediatric cardiologist at Heidelberg University Hospital, focused on certain genetic mutations. These mutations were suspected of triggering congenital heart defects in humans. Through modifying individual building blocks of the DNA of the relevant genes in the model organism, the scientists were able to imitate and study fish embryos with the described heart defects. The targeted intervention led to visible changes in the heart already during early stages of fish embryonic development, say Bettina Welz and Dr Alex Cornean, two of the first authors of the study from Prof. Wittbrodt's team. That enabled the researchers to confirm the original suspicion and establish a causal connection between genetic alteration and clinical symptoms.

The precise intervention in the genome of the fish embryos was made possible through especially developed software ACEofBASEs, which is available online. It allows for identifying genetic locations that very efficiently lead to desired changes in the target genes and the resultant proteins. The scientists say that the Japanese ricefish is an excellent genetic model organism for modelling mutations like those identified from the respective patients. "Our method enables an efficient screening analysis and could therefore offer a starting point for developing individualised medical treatment," according to Jakob Gierten.

A third study, again from the Wittbrodt group, deals with the limitations of base editors. For such an editor to bind the DNA of a target cell, there has to be a certain sequence motif. It is called Protospacer Adjacent Motif, PAM for short. "If this motif is lacking near the DNA building block to be changed, it is impossible to exchange nucleotides," explains Dr Thumberger. A team under his direction has now found a way to get around this limitation. Two base editors in a single cell are used in succession. In an initial step, a new DNA binding motif for a further base editor is generated, upon which this second editor, which is applied simultaneously, can edit a site that was inaccessible before. This staggered use turned out to be highly efficient, explains Kaisa Pakari, the first author of the study. With this trick, the Heidelberg scientists were able to increase the number of possible application sites of established base editors by 65 percent. Now DNA sequences that were initially inaccessible can also be modified.

"Optimising the existing tools for genome editing and their fine-tuned application results in enormously varied possibilities for basic research and, potentially, novel therapeutic approaches," Joachim Wittbrodt underlines.

Read more at Science Daily

Massive fuel-hungry black holes feed off intergalactic gas

Research led by the University of Southampton has revealed how supermassive black holes (SMBHs) are feeding off gas clouds which reach them by travelling hundreds of thousands of light years from one galaxy to another.

An international team of scientists has shown there is a crucial link between the interaction of neighbouring galaxies and the enormous amount of gas needed to 'fuel' these giant, super-dense, space phenomena. Their findings are due to be published in the journal Nature Astronomy.

A black hole can be created when a star collapses, squeezing matter into a relatively tiny space. This increases the force of gravity to a point where nothing can escape, not even light -- hence the name.

Some black holes are gigantic, with masses millions of times greater than our sun, emitting enormous amounts of energy. These are known as 'supermassive black holes' and exactly how they are formed or gain enough fuel to power themselves is still a mystery.

Astrophysicist and lead researcher from the University of Southampton, Dr Sandra Raimundo, comments: "Supermassive black holes fuel their activity by, in part, the gradual accumulation of gas from the environment around them. Supermassive black holes can make the centres of galaxies shine very brightly when they capture gas and it's thought this process can be a major influence on the way that galaxies look today. How SMBHs get enough fuel to sustain their activity and growth still puzzles astronomers, but the work we have carried out provides a step towards understanding this."

The Southampton scientist, working with researchers at the universities of Copenhagen and California, used data from the 4-metre Anglo-Australian telescope in New South Wales, Australia* to study the orbits of gas and stars in a large sample of more than 3000 galaxies. They identified those with the presence of what is known as 'misaligned' gas -- in other words, gas which rotates in a different direction from the stars in the galaxy, signalling a past galaxy interaction. They then found that galaxies with misaligned gas had a higher fraction of active supermassive black holes.

The results showed a clear link between misaligned gas and supermassive black hole activity -- suggesting the gas is transferred where two galaxies meet, meanders vast distances through space and then succumbs to the huge gravitational forces of the supermassive black hole -- pulled in and swallowed up as a vital source of fuel. Astronomers have long suspected that a merger with another galaxy could provide this source of gas, but direct evidence for this has been elusive.

Dr Raimundo explains: "The work that we carried out shows the presence of gas that is misaligned from stars is associated with an increase in the fraction of active supermassive black holes. Since misaligned gas is a clear sign of a past interaction between two galaxies, our work shows that galaxy interactions provide fuel to power active supermassive black holes.

"This is the first time that a direct connection has been observed between the formation and presence of misaligned gas and the fuelling of active supermassive black holes."

Dr Marianne Vestergaard, a co-author in the study, highlights: "What is exciting about these observations is that we can now, for the very first time, identify the captured gas and trace it all the way to the centre where the black hole is devouring it."

Read more at Science Daily

Bacteria really eat plastic

The bacterium Rhodococcus ruber eats and actually digests plastic. This has been shown in laboratory experiments by PhD student Maaike Goudriaan at Royal Netherlands Institute for Sea Research (NIOZ). Based on a model study with plastic in artificial seawater in the lab, Goudriaan calculated that bacteria can break down about one percent of the fed plastic per year into CO2 and other harmless substances. "But," Goudriaan emphasizes, "this is certainly not a solution to the problem of the plastic soup in our oceans. It is, however, another part of the answer to the question of where all the 'missing plastic' in the oceans has gone."

Special plastic

Goudriaan had a special plastic manufactured especially for these experiments with a distinct form of carbon (13C) in it. When she fed that plastic to bacteria after pretreatment with "sunlight" -- a UV lamp -- in a bottle of simulated seawater, she saw that special version of carbon appear as CO2 above the water. "The treatment with UV light was necessary because we already know that sunlight partially breaks down plastic into bite-sized chunks for bacteria," the researcher explains.

Proof of principle

"This is the first time we have proven in this way that bacteria actually digest plastic into CO2 and other molecules," Goudriaan states. It was already known that the bacterium Rhodococcus ruber can form a so-called biofilm on plastic in nature. It had also been measured that plastic disappears under that biofilm. "But now we have really demonstrated that the bacteria actually digest the plastic."

Underestimate

When Goudriaan calculates the total breakdown of plastic into CO2, she estimates that the bacteria can break down about one percent of the available plastic per year. "That's probably an underestimate," she adds. "We only measured the amount of carbon-13 in CO2, so not in the other breakdown products of the plastic. There will certainly be 13C in several other molecules, but it's hard to say what part of that was broken down by the UV light and what part was digested by the bacteria."

No solution

Even though marine microbiologist Goudriaan is very excited about the plastic-eating bacteria, she stresses that microbial digestion is not a solution to the huge problem of all the plastic floating on and in our oceans. "These experiments are mainly a proof of principle. I see it as one piece of the jigsaw, in the issue of where all the plastic that disappears into the oceans stays. If you try to trace all our waste, a lot of plastic is lost. Digestion by bacteria could possibly provide part of the explanation."

From lab to mudflats

To discover whether 'wild' bacteria also eat plastic 'in the wild', follow-up research needs to be done. Goudriaan already did some pilot experiments with real sea water and some sediment that she had collected from the Wadden Sea floor. "The first results of these experiments hints at plastic being degraded, even in nature," she says. "A new PhD student will have to continue that work. Ultimately, of course, you hope to calculate how much plastic in the oceans really is degraded by bacteria. But much better than cleaning up, is prevention. And only we humans can do that," Goudriaan says.

Read more at Science Daily

'Smart' walking stick could help visually impaired with groceries, finding a seat

Engineers at the University of Colorado Boulder are tapping into advances in artificial intelligence to develop a new kind of walking stick for people who are blind or visually impaired.

Think of it as assistive technology meets Silicon Valley.

The researchers say that their "smart" walking stick could one day help blind people navigate tasks in a world designed for sighted people -- from shopping for a box of cereal at the grocery store to picking a private place to sit in a crowded cafeteria.

"I really enjoy grocery shopping and spend a significant amount of time in the store," said Shivendra Agrawal, a doctoral student in the Department of Computer Science. "A lot of people can't do that, however, and it can be really restrictive. We think this is a solvable problem."

In a study published in October, Agrawal and his colleagues in the Collaborative Artificial Intelligence and Robotics Lab got one step closer to solving it.

The team's walking stick resembles the white-and-red canes that you can buy at Walmart. But it also includes a few add-ons: Using a camera and computer vision technology, the walking stick maps and catalogs the world around it. It then guides users by using vibrations in the handle and with spoken directions, such as "reach a little bit to your right."

The device isn't supposed to be a substitute for designing places like grocery stores to be more accessible, Agrawal said. But he hopes his team's prototype will show that, in some cases, AI can help millions of Americans become more independent.

"AI and computer vision are improving, and people are using them to build self-driving cars and similar inventions," Agrawal said. "But these technologies also have the potential to improve quality of life for many people."

Take a seat

Agrawal and his colleagues first explored that potential by tackling a familiar problem: Where do I sit?

"Imagine you're in a café," he said. "You don't want to sit just anywhere. You usually take a seat close to the walls to preserve your privacy, and you usually don't like to sit face-to-face with a stranger."

Previous research has suggested that making these kinds of decisions is a priority for people who are blind or visually impaired. To see if their smart walking stick could help, the researchers set up a café of sorts in their lab -- complete with several chairs, patrons and a few obstacles.

Study subjects strapped on a backpack with a laptop in it and picked up the smart walking stick. They swiveled to survey the room with a camera attached near the cane handle. Like a self-driving car, algorithms running inside the laptop identified the various features in the room then calculated the route to an ideal seat.

The team reported its findings this fall at the International Conference on Intelligent Robots and Systems in Kyoto, Japan. Researchers on the study included Bradley Hayes, assistant professor of computer science, and doctoral student Mary Etta West.

The study showed promising results: Subjects were able to find the right chair in 10 out of 12 trials with varying levels of difficulty. So far, the subjects have all been sighted people wearing blindfolds. But the researchers plan to evaluate and improve their device by working people who are blind or visually impaired once the technology is more dependable.

"Shivendra's work is the perfect combination of technical innovation and impactful application, going beyond navigation to bring advancements in underexplored areas, such as assisting people with visual impairment with social convention adherence or finding and grasping objects," Hayes said.

Let's go shopping

Next up for the group: grocery shopping.

In new research, which the team hasn't yet published, Agrawal and his colleagues adapted their device for a task that can be daunting for anyone: finding and grasping products in aisles filled with dozens of similar-looking and similar-feeling choices.

Again, the team set up a makeshift environment in their lab: this time, a grocery shelf stocked with several different kinds of cereal. The researchers created a database of product photos, such as boxes of Honey Nut Cheerios or Apple Jacks, into their software. Study subjects then used the walking stick to scan the shelf, searching for the product they wanted.

"It assigns a score to the objects present, selecting what is the most likely product," Agrawal said. "Then the system issues commands like 'move a little bit to your left.'"

He added that it will be a while before the team's walking stick makes it into the hands of real shoppers. The group, for example, wants to make the system more compact, designing it so that it can run off a standard smartphone attached to a cane.

But the human-robot interaction researchers also hope that their preliminary results will inspire other engineers to rethink what robotics and AI are capable of.

Read more at Science Daily

We need to learn to live with less steel

Steel is one of the most important materials in the world, integral to the cars we drive, the buildings we inhabit, and the infrastructure that allows us to travel from place to place. Steel is also responsible for 7% of global greenhouse gas emissions. In 2021, 45 countries made a commitment to pursue near-zero-emission steel in the next decade. But how possible is it to produce the steel we need in society with zero emissions?

A new study focused on the Japanese steel industry shows that if we are truly committed to reaching zero emissions, we must be prepared for a scenario where the amount of steel we can produce is lower. Japan has set a target for a 46% reduction in emissions from steel by 2030, and zero emissions by 2050. So far, the roadmap for achieving this relies heavily on future innovations in technology. Hope is held out for developments in carbon capture and storage (CCS) and hydrogen-based technologies.

In the study, Dr. Takuma Watari, a researcher at the National Institute for Environmental Studies, Japan, currently working with the University of Cambridge, argues that there is no silver bullet. He says that current plans to cut carbon emissions underestimate how difficult it will be to develop CCS and hydrogen technologies and deploy them widely: "These technologies still face serious technical, economic, and social challenges, and have yet to be implemented at scale. And importantly, it is highly uncertain whether there will be sufficient non-emitting electricity to use these technologies." We need to confront the possibility that technological innovations might not be ready in time to allow us to maintain current levels of steel production whilst cutting emissions to zero.

The research involved mapping the current flows of steel in Japan's industry and using a model to explore how the industry might change if a strict carbon budget were applied in future. Dr. Watari explains that with current practice, the quantity and quality of steel produced would dramatically decrease under a zero-emission carbon budget. This is because of a lack of resources and the practice of downcycling, in which scraps of steel containing impurities are used to make new products. It is difficult to remove these impurities, so the new products have different quality and functionality from the original steel.

According to Dr. Watari, "zero-emission steel production is possible by 2050, but in limited quantity and quality compared to current total production. This is due to the limited availability of zero-emission compatible resources and downcycling practices of scrap steel."

The research indicates that with a carbon budget of zero emissions, the production of steel goods would be dramatically restricted compared to today, reaching about half the current levels at best. In this case, higher-quality steel production (e.g., sheet steel) would be especially hard hit.

The implication is clear. It is not enough to rely on a technological silver bullet materialising to transform the supply of steel. We also need to look seriously at strategies to reduce demand by shifting our culture of steel use and improving our material efficiency. We also need to pursue upcycling to produce high-grade steel from scrap steel.

This will require collaboration from those who use steel as well as those who produce it. Steel products could be made more resource efficient if they are designed to last longer or to be lightweight. Once steel products reach the end of their life, upcycling could be achieved through advanced sorting and shredding to remove impurities from scrap steel. As a society, Japan may also have to become less steel-dependent and shift to a model of 'service use' rather than ownership of products. Unlike today, when steel is abundant and cheap, a net-zero future will require us to use scarcer, more expensive steel resources with greater efficiency. 

Read more at Science Daily

The mechanism of cosmic magnetic fields explored in the laboratory

Recent research shows that magnetic fields can spontaneously emerge in a plasma if the plasma has a temperature anisotropy. This mechanism is known as the Weibel instability. This new research is the first to unambiguously observe the Weibel instability in the laboratory. It offers a possible solution to the problem of the origin of the microgauss-level magnetic fields that permeate the galaxies.

Plasma is matter that is so hot that the electrons are separated from atoms. The electrons float freely and the atoms become ions. This creates an ionized gas -- plasma -- that makes up nearly all of the visible universe. Recent research shows that magnetic fields can spontaneously emerge in a plasma. This can happen if the plasma has a temperature anisotropy -- temperature that is different along different spatial directions. This mechanism is known as the Weibel instability. It was predicted by plasma theorist Eric Weibel more than six decades ago but only now has been unambiguously observed in the laboratory. The new research finds that this process can convert a significant fraction of the energy stored in the temperature anisotropy into magnetic field energy. It also finds that the Weibel instability could be a source of magnetic fields that permeate throughout the cosmos.

The Impact

The matter in our observable universe is plasma state and it is magnetized. Magnetic fields at the micro-gauss level (about a millionth of the Earth's magnetic fields) permeate the galaxies. These magnetic fields are thought to be amplified from weak seed fields by the spiral motion of the galaxies, known as the galactic dynamo. How the seed magnetic fields are created is a longstanding question in astrophysics. This new work offers a possible solution to this vexing problem of the origin of the microgauss level seed magnetic fields. The research used a novel platform that has great potential for studying the ultrafast dynamics of magnetic fields in the laboratory plasmas that are relevant to astro- and high-energy density physics.

Summary

First theorized six decades ago, the Weibel instability driven by temperature anisotropy is thought to be an important mechanism for self-magnetization of many laboratory and astrophysical plasmas. However, scientists have faced two challenges in unambiguously demonstrating the Weibel instability. First, until recently, researchers were not able to generate a plasma with a known temperature anisotropy as initially envisioned by Weibel. Second, researchers had no suitable technique to measure the complex and rapidly evolving topology of the magnetic fields subsequently generated in the plasma.

This work, enabled by the unique capability of the Accelerator Test Facility, a Department of Energy (DOE) user facility at Brookhaven National Laboratory, employed a novel experimental platform that allowed the researchers to create a hydrogen plasma with a known highly anisotropic electron velocity distributions on a tens of trillionth of a second timescale by using an ultrashort but intense carbon dioxide laser pulse. The subsequent thermalization of the plasma occurs via self-organization of plasma currents that produces magnetic fields driven by Weibel instability. These fields are large enough to deflect relativistic electrons to reveal an image of the magnetic fields a certain distance from the plasma. The researchers obtained a movie of the evolution of these magnetic fields with exquisite spatiotemporal resolution by using an one picosecond relativistic electron beam to probe these fields.

Read more at Science Daily

New small laser device can help detect signs of life on other planets

As space missions delve deeper into the outer solar system, the need for more compact, resource-conserving and accurate analytical tools has become increasingly critical -- especially as the hunt for extraterrestrial life and habitable planets or moons continues.

A University of Maryland-led team developed a new instrument specifically tailored to the needs of NASA space missions. Their mini laser-sourced analyzer is significantly smaller and more resource efficient than its predecessors -- all without compromising the quality of its ability to analyze planetary material samples and potential biological activity onsite. The team's paper on this new device was published in the journal Nature Astronomy on January 16, 2023.

Weighing only about 17 pounds, the instrument is a physically scaled-down combination of two important tools for detecting signs of life and identifying compositions of materials: a pulsed ultraviolet laser that removes small amounts of material from a planetary sample and an OrbitrapTM analyzer that delivers high-resolution data about the chemistry of the examined materials.

"The Orbitrap was originally built for commercial use," explained Ricardo Arevalo, lead author of the paper and an associate professor of geology at UMD. "You can find them in the labs of pharmaceutical, medical and proteomic industries. The one in my own lab is just under 400 pounds, so they're quite large, and it took us eight years to make a prototype that could be used efficiently in space -- significantly smaller and less resource-intensive, but still capable of cutting-edge science."

The team's new gadget shrinks down the original Orbitrap while pairing it with laser desorption mass spectrometry (LDMS) -- techniques that have yet to be applied in an extraterrestrial planetary environment. The new device boasts the same benefits as its larger predecessors but is streamlined for space exploration and onsite planetary material analysis, according to Arevalo.

Thanks to its diminutive mass and minimal power requirements, the mini Orbitrap LDMS instrument can be easily stowed away and maintained on space mission payloads. The instrument's analyses of a planetary surface or substance are also far less intrusive and thus much less likely to contaminate or damage a sample than many current methods that attempt to identify unknown compounds.

"The good thing about a laser source is that anything that can be ionized can be analyzed. If we shoot our laser beam at an ice sample, we should be able to characterize the composition of the ice and see biosignatures in it," Arevalo said. "This tool has such a high mass resolution and accuracy that any molecular or chemical structures in a sample become much more identifiable."

The laser component of the mini LDMS Orbitrap also allows researchers access to larger, more complex compounds that are more likely to be associated with biology. Smaller organic compounds like amino acids, for example, are more ambiguous signatures of life forms.

"Amino acids can be produced abiotically, meaning that they're not necessarily proof of life. Meteorites, many of which are chock full of amino acids, can crash onto a planet's surface and deliver abiotic organics to the surface," Arevalo said. "We know now that larger and more complex molecules, like proteins, are more likely to have been created by or associated with living systems. The laser lets us study larger and more complex organics that can reflect higher fidelity biosignatures than smaller, simpler compounds."

For Arevalo and his team, the mini LDMS Orbitrap will offer much-needed insight and flexibility for future ventures into the outer solar system, such as missions focused on life detection objectives (e.g., Enceladus Orbilander) and exploration of the lunar surface (e.g., the NASA Artemis Program). They hope to send their device into space and deploy it on a planetary target of interest within the next few years.

"I view this prototype as a pathfinder for other future LDMS and Orbitrap-based instruments," Arevalo said. "Our mini Orbitrap LDMS instrument has the potential to significantly enhance the way we currently study the geochemistry or astrobiology of a planetary surface."

Read more at Science Daily

Rest isn't best: Getting kids back to school sooner after a concussion can mean a faster recovery

Contrary to popular belief, rest may not always be the best cure after a concussion, new study published in JAMA Network Open finds. In fact, an early return to school may be associated with a lower symptom burden after suffering a concussion and, ultimately, faster recovery.

"We know that absence from school can be detrimental to youth in many ways and for many reasons," says Christopher Vaughan, Psy.D., neuropsychologist at Children's National Hospital and the study's lead author. "The results of this study found that, in general, an earlier return to school after a concussion was associated with better outcomes. This helps us feel reassured that returning to some normal activities after a concussion -- like going to school -- is ultimately beneficial."

In this cohort study, data from over 1,600 youth aged 5 to 18 were collected across nine pediatric emergency departments in Canada. Because of the large sample size, many factors associated with greater symptom burden and prolonged recovery were first accounted for through the complex statistical approach used to examine the data. The authors found that an early return to school was associated with a lower symptom burden 14 days post-injury in the 8 to 12 and 13 to 18-year-old age groups.

"Clinicians can now confidently inform families that missing at least some school after a concussion is common, often between 2 and 5 days, with older kids typically missing more school," Dr. Vaughan says. "But the earlier a child can return to school with good symptom management strategies and with appropriate academic supports, the better that we think that their recovery will be."

Read more at Science Daily