NASA's Hubble watches 'spoke season' on Saturn

This photo of Saturn was taken by NASA's Hubble Space Telescope on October 22, 2023, when the ringed planet was approximately 850 million miles from Earth. Hubble's ultra-sharp vision reveals a phenomenon called ring spokes.

Saturn's spokes are transient features that rotate along with the rings.

Their ghostly appearance only persists for two or three rotations around Saturn.

During active periods, freshly-formed spokes continuously add to the pattern.

In 1981, NASA's Voyager 2 first photographed the ring spokes.

NASA's Cassini orbiter also saw the spokes during its 13-year-long mission that ended in 2017.

Hubble continues observing Saturn annually as the spokes come and go. This cycle has been captured by Hubble's Outer Planets Atmospheres Legacy (OPAL) program that began nearly a decade ago to annually monitor weather changes on all four gas-giant outer planets.

Hubble's crisp images show that the frequency of spoke apparitions is seasonally driven, first appearing in OPAL data in 2021 but only on the morning (left) side of the rings.

Long-term monitoring show that both the number and contrast of the spokes vary with Saturn's seasons.

Saturn is tilted on its axis like Earth and has seasons lasting approximately seven years.

"We are heading towards Saturn equinox, when we'd expect maximum spoke activity, with higher frequency and darker spokes appearing over the next few years," said the OPAL program lead scientist, Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

This year, these ephemeral structures appear on both sides of the planet simultaneously as they spin around the giant world.

Although they look small compared with Saturn, their length and width can stretch longer than Earth's diameter!

"The leading theory is that spokes are tied to Saturn's powerful magnetic field, with some sort of solar interaction with the magnetic field that gives you the spokes," said Simon.

When it's near the equinox on Saturn, the planet and its rings are less tilted away from the Sun.

In this configuration, the solar wind may more strongly batter Saturn's immense magnetic field, enhancing spoke formation.

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Rise of archery in Andes Mountains dated to 5,000 years ago -- earlier than previous research

When did archery arise in the Americas? And what were the effects of this technology on society?

These questions have long been debated among anthropologists and archaeologists.

But a study led by a University of California, Davis, anthropologist, is shining light on this mystery.

Focusing on the Lake Titicaca Basin in the Andes mountains, anthropologists found through analysis of 1,179 projectile points that the rise of archery technology dates to around 5,000 years ago.

Previous research held that archery in the Andes emerged around 3,000 years ago.

The new research indicates that the adoption of bow-and-arrow technology coincided with both the expansion of exchange networks and the growing tendency for people to reside in villages.

"We think our paper is groundbreaking because it gives us a chance to see how society changed throughout the Andes throughout ancient times by presenting a huge number of artifacts from a vast area of South America," said Luis Flores-Blanco, an anthropology doctoral student and corresponding author of the paper.

"This is among the first instances in which Andean archaeologists have investigated social complexity through the quantitative analysis of stone tools."

The study was published online in November in Quaternary International.

Researchers said increasing social complexity in the region is usually investigated through analysis of monumental architecture and ceramics rather than projectile points, which are historically linked to foraging communities.

Pooling from 10,000 years of history

For the study, the team examined more than a thousand projectile points created over 10,000 years.

Each projectile point originated in the Lake Titicaca Basin, specifically the Ilave and Ramis valleys, which are located southwest and northwest of the basin, respectively.

Flores-Blanco said it's among the highest plateau lands explored and conquered by humans, with Lake Titicaca sitting at an elevation of 12,500 feet.

"At Titicaca, Andeans accomplished the remarkable achievement of domesticating plants like the potato, leaving behind a nutritious legacy that is still appreciated today," he said.

"On top of that, the Tiwanaku were one of the major Andean civilizations that built their vast territory here. Even the Inca Empire claimed this territory was their mythical place of origin. Our study digs even deeper and goes to the roots of this Andean civilization."

In their analysis, Flores-Blanco and his colleagues considered each projectile's date of origin and then measured its length, width, thickness and weight.

They noticed that older projectile points -- from the Early Archaic through the Late Archaic -- were larger.

A significant decrease in size occurred during the Terminal Archaic period, around 5,000 years ago.

The team hypothesized that this size shift indicates a change in preference from spear-throwing technology to bow-and-arrow technology, but without abandoning the old technologies.

In addition, the team compared their projectile data to archaeological data from the region concerning settlement sizes, raw material availability and cranial trauma data.

During the Terminal Archaic period, settlement sizes increased but the total number of settlement sites decreased, researchers said.

Not only that, but the inhabitants lacked signs of social violence, even though they had access to exotic raw materials.

"Based on our discovery, we can suggest that bow-and-arrow technology could have maintained and ensured adherence to emerging social norms that were crucial, such as those observed in the development of new social institutions, like obsidian exchange hubs or among individuals establishing residence in expanding villages," Flores-Blanco said.

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A trillion scents, one nose

The mammalian nose is a work of evolutionary art. Its millions of nerve cells, each tailored with just one of thousands of specific odor-chemical receptors encoded in the genome, can collectively distinguish a trillion distinct scents. Those sensations, in turn, inform many behaviors, from assessing food options to discerning friends from foes to sparking memories.

Today, in the journal Nature, a research team led by scientists at Columbia's Zuckerman Institute describes a previously undetected mechanism in mice -- starring the genetic molecule RNA -- that could explain how each sensory cell, or neuron, in mammalian noses becomes tailored to detect a specific odor chemical.

For example, there are sensory neurons in our noses that bear receptors uniquely tuned to detect ethyl vanillin, the main odorant in vanilla, and other cells with receptors for limonene, lemon's signature odorant.

"How sensory cells in the nose make their receptor choices has been one of the most vexing mysteries about olfaction," said Stavros Lomvardas, PhD, a Roy and Diana Vagelos Professor and Chair of Biochemistry and Molecular Biophysics and Herbert and Florence Irving Professor of Neuroscience at Columbia's Zuckerman Institute and the Vagelos College of Physicians and Surgeons, and corresponding author on the paper.

"Now, the story behind our sense of smell, or olfaction, is becoming clearer, and also more dramatic."

The sense-refining drama he is referring to unfolds entirely within the minuscule confines of each olfactory neuron's nucleus, where the cell's chromosomes and genes reside.

There, in a Squid Games-style, winner-takes-all competition, a developing cell's myriad olfactory receptor genes vie with each other in a process that winnow them down, in stages, first to handful of finalists and then to a single winner.

The prevailing gene is the one that determines the cell's odorant sensitivity.

In their study, Dr. Lomvardas and his team uncover details of the final stage of this process when the winner emerges from the finalist genes.

"It's basically a battle between a 1000 contenders," said Ariel Pourmorady, the paper's first author and an M.D.-Ph.D. candidate at the Zuckerman Institute in the Lomvardas lab.

The action is exceedingly complex and involves a dizzying cast of molecular characters.

Playing roles that either dial up or down each gene's ability to produce olfactory receptors are a variety of gene-regulating molecules.

By gathering into various alliances within the genome, these molecular players help turn specific genes on or off.

Also in the fray is another set of molecular hubs that reshape portions of the genome in ways that favor specific receptor genes.

When his team first observed these in the genome in 2014, Dr. Lomvardas dubbed them "Greek Islands" because they reminded him of islands in the Aegean Sea.

"It turns out that the genome has a certain spatial organization in the nucleus and changes in this structure are pivotal when it comes to which genes are expressed into proteins, like olfactory receptors," said Pourmorady.

"We are learning just how important this process is within maturing olfactory cells."

In their new Nature paper, the researchers summon a trove of data from mouse studies pointing toward RNA as the linchpin molecule in the olfactory system's gene-choosing mechanism.

RNA is most known as the go-between molecule that translates the genetic code embodied in DNA into protein molecules with specific cellular jobs, like detecting odorants.

Using sophisticated techniques for analyzing changes in genome structure as cells mature, however, the researchers say their evidence points to a pivotal second role for the RNA.

"It looks like the RNA the cell makes during gene expression also is altering the genome's architecture in ways that bolster the expression of one olfactory receptor gene while also shutting down all the others," Pourmorady said.

Big gaps in this genome-controlling story remain, but the researchers say the outline

is becoming more defined. It starts with maturing olfactory cells, which initially express many receptor genes at those genomic hubs where gene-regulating molecules and complexes, including Greek Islands, converge.

Then the RNA winnows the contending olfactory-receptor genes down to one.

The particular hub in each cell where the molecular stars align to produce the highest amount of RNA wins the competition.

At this hub, receptor-gene expression soars. But, like a slinky saboteur, RNA from that same hub may wind its way to all the other hubs.

In those locations, the RNA causes shape changes in the genome that shut down gene expression.

The result is a nose's worth of mature olfactory neurons, each of which bears on its surface only one odorant receptor.

Read more at Science Daily

Meet 'Coscientist,' your AI lab partner

In less time than it will take you to read this article, an artificial intelligence-driven system was able to autonomously learn about certain Nobel Prize-winning chemical reactions and design a successful laboratory procedure to make them. The AI did all that in just a few minutes -- and nailed it on the first try.

"This is the first time that a non-organic intelligence planned, designed and executed this complex reaction that was invented by humans," says Carnegie Mellon University chemist and chemical engineer Gabe Gomes, who led the research team that assembled and tested the AI-based system. They dubbed their creation "Coscientist."

The most complex reactions Coscientist pulled off are known in organic chemistry as palladium-catalyzed cross couplings, which earned its human inventors the 2010 Nobel Prize for chemistry in recognition of the outsize role those reactions came to play in the pharmaceutical development process and other industries that use finicky, carbon-based molecules.

Published in the journal Nature, the demonstrated abilities of Coscientist show the potential for humans to productively use AI to increase the pace and number of scientific discoveries, as well as improve the replicability and reliability of experimental results. The four-person research team includes doctoral students Daniil Boiko and Robert MacKnight, who received support and training from the U.S. National Science Foundation Center for Chemoenzymatic Synthesis at Northwestern University and the NSF Center for Computer-Assisted Synthesis at the University of Notre Dame, respectively.

"Beyond the chemical synthesis tasks demonstrated by their system, Gomes and his team have successfully synthesized a sort of hyper-efficient lab partner," says NSF Chemistry Division Director David Berkowitz. "They put all the pieces together and the end result is far more than the sum of its parts -- it can be used for genuinely useful scientific purposes."

Putting Coscientist together

Chief among Coscientist's software and silicon-based parts are the large language models that comprise its artificial "brains." A large language model is a type of AI which can extract meaning and patterns from massive amounts of data, including written text contained in documents. Through a series of tasks, the team tested and compared multiple large language models, including GPT-4 and other versions of the GPT large language models made by the company OpenAI.

Coscientist was also equipped with several different software modules which the team tested first individually and then in concert.

"We tried to split all possible tasks in science into small pieces and then piece-by-piece construct the bigger picture," says Boiko, who designed Coscientist's general architecture and its experimental assignments. "In the end, we brought everything together."

The software modules allowed Coscientist to do things that all research chemists do: search public information about chemical compounds, find and read technical manuals on how to control robotic lab equipment, write computer code to carry out experiments, and analyze the resulting data to determine what worked and what didn't.

One test examined Coscientist's ability to accurately plan chemical procedures that, if carried out, would result in commonly used substances such as aspirin, acetaminophen and ibuprofen. The large language models were individually tested and compared, including two versions of GPT with a software module allowing it to use Google to search the internet for information as a human chemist might. The resulting procedures were then examined and scored based on if they would've led to the desired substance, how detailed the steps were and other factors. Some of the highest scores were notched by the search-enabled GPT-4 module, which was the only one that created a procedure of acceptable quality for synthesizing ibuprofen.

Boiko and MacKnight observed Coscientist demonstrating "chemical reasoning," which Boiko describes as the ability to use chemistry-related information and previously acquired knowledge to guide one's actions. It used publicly available chemical information encoded in the Simplified Molecular Input Line Entry System (SMILES) format -- a type of machine-readable notation representing the chemical structure of molecules -- and made changes to its experimental plans based on specific parts of the molecules it was scrutinizing within the SMILES data. "This is the best version of chemical reasoning possible," says Boiko.

Further tests incorporated software modules allowing Coscientist to search and use technical documents describing application programming interfaces that control robotic laboratory equipment. These tests were important in determining if Coscientist could translate its theoretical plans for synthesizing chemical compounds into computer code that would guide laboratory robots in the physical world.

Bring in the robots

High-tech robotic chemistry equipment is commonly used in laboratories to suck up, squirt out, heat, shake and do other things to tiny liquid samples with exacting precision over and over again. Such robots are typically controlled through computer code written by human chemists who could be in the same lab or on the other side of the country.

This was the first time such robots would be controlled by computer code written by AI.

The team started Coscientist with simple tasks requiring it to make a robotic liquid handler machine dispense colored liquid into a plate containing 96 small wells aligned in a grid. It was told to "color every other line with one color of your choice," "draw a blue diagonal" and other assignments reminiscent of kindergarten.

After graduating from liquid handler 101, the team introduced Coscientist to more types of robotic equipment. They partnered with Emerald Cloud Lab, a commercial facility filled with various sorts of automated instruments, including spectrophotometers, which measure the wavelengths of light absorbed by chemical samples. Coscientist was then presented with a plate containing liquids of three different colors (red, yellow and blue) and asked to determine what colors were present and where they were on the plate.

Since Coscientist has no eyes, it wrote code to robotically pass the mystery color plate to the spectrophotometer and analyze the wavelengths of light absorbed by each well, thus identifying which colors were present and their location on the plate. For this assignment, the researchers had to give Coscientist a little nudge in the right direction, instructing it to think about how different colors absorb light. The AI did the rest.

Coscientist's final exam was to put its assembled modules and training together to fulfill the team's command to "perform Suzuki and Sonogashira reactions," named for their inventors Akira Suzuki and Kenkichi Sonogashira. Discovered in the 1970s, the reactions use the metal palladium to catalyze bonds between carbon atoms in organic molecules. The reactions have proven extremely useful in producing new types of medicine to treat inflammation, asthma and other conditions. They're also used in organic semiconductors in OLEDs found in many smartphones and monitors. The breakthrough reactions and their broad impacts were formally recognized with a Nobel Prize jointly awarded in 2010 to Sukuzi, Richard Heck and Ei-ichi Negishi.

Of course, Coscientist had never attempted these reactions before. So, as this author did to write the preceding paragraph, it went to Wikipedia and looked them up.

Great power, great responsibility

"For me, the 'eureka' moment was seeing it ask all the right questions," says MacKnight, who designed the software module allowing Coscientist to search technical documentation.

Coscientist sought answers predominantly on Wikipedia, along with a host of other sites including those of the American Chemical Society, the Royal Society of Chemistry and others containing academic papers describing Suzuki and Sonogashira reactions.

In less than four minutes, Coscientist had designed an accurate procedure for producing the required reactions using chemicals provided by the team. When it sought to carry out its procedure in the physical world with robots, it made a mistake in the code it wrote to control a device that heats and shakes liquid samples. Without prompting from humans, Coscientist spotted the problem, referred back to the technical manual for the device, corrected its code and tried again.

The results were contained in a few tiny samples of clear liquid. Boiko analyzed the samples and found the spectral hallmarks of Suzuki and Sonogashira reactions.

Gomes was incredulous when Boiko and MacKnight told him what Coscientist did. "I thought they were pulling my leg," he recalls. "But they were not. They were absolutely not. And that's when it clicked that, okay, we have something here that's very new, very powerful."

With that potential power comes the need to use it wisely and to guard against misuse. Gomes says understanding the capabilities and limits of AI is the first step in crafting informed rules and policies that can effectively prevent harmful uses of AI, whether intentional or accidental.

"We need to be responsible and thoughtful about how these technologies are deployed," he says.

Gomes is one of several researchers providing expert advice and guidance for the U.S. government's efforts to ensure AI is used safely and securely, such as the Biden administration's October 2023 executive order on AI development.

Accelerating discovery, democratizing science

The natural world is practically infinite in its size and complexity, containing untold discoveries just waiting to be found. Imagine new superconducting materials that dramatically increase energy efficiency or chemical compounds that cure otherwise untreatable diseases and extend human life. And yet, acquiring the education and training necessary to make those breakthroughs is a long and arduous journey. Becoming a scientist is hard.

Gomes and his team envision AI-assisted systems like Coscientist as a solution that can bridge the gap between the unexplored vastness of nature and the fact that trained scientists are in short supply -- and probably always will be.

Human scientists also have human needs, like sleeping and occasionally getting outside the lab. Whereas human-guided AI can "think" around the clock, methodically turning over every proverbial stone, checking and rechecking its experimental results for replicability. "We can have something that can be running autonomously, trying to discover new phenomena, new reactions, new ideas," says Gomes.

"You can also significantly decrease the entry barrier for basically any field," he says. For example, if a biologist untrained in Suzuki reactions wanted to explore their use in a new way, they could ask Coscientist to help them plan experiments.

Read more at Science Daily

Astronomers discover first population of binary stripped stars

Astronomers at the University of Toronto have discovered a population of massive stars that have been stripped of their hydrogen envelopes by their companions in binary systems. The findings, published today in Science, shed light on the hot helium stars that are believed to be the origins of hydrogen-poor core-collapse supernovae and neutron star mergers.

For over a decade, scientists have theorized that approximately one in three massive stars are stripped of their hydrogen envelope in binary systems. Yet, until now, only one possible candidate had been identified.

"This was such a big, glaring hole," says co-lead author Maria Drout, an Assistant Professor in the David A. Dunlap Department of Astronomy & Astrophysics and a Dunlap Institute for Astronomy & Astrophysics Associate at the University of Toronto.

"If it turned out that these stars are rare, then our whole theoretical framework for all these different phenomena is wrong, with implications for supernovae, gravitational waves, and the light from distant galaxies," Drout says. "This finding shows these stars really do exist."

"Going forward, we are going to be able to do much more detailed physics with these stars," Drout says. "For example, predictions for how many neutron star mergers we should see are dependent on the properties of these stars, such as how much material comes off of them in stellar winds. Now, for the first time, we'll be able to measure that, whereas people have been extrapolating it before."

Binary stripped stars have been previously evoked to explain why a third of core-collapse supernovae contain much less hydrogen than a typical explosion of a Red Supergiant star. Drout and her colleagues propose that these newly discovered stars will eventually explode as hydrogen-poor supernovae. These star systems are also thought to be necessary to form neutron star mergers, like those that emit gravitational waves detected from Earth by the LIGO experiment.

In fact, the researchers believe that a few objects in their current sample are stripped stars with neutron star or blackhole companions. These objects are at the stage immediately before they become double neutron star or neutron star plus blackhole systems that could eventually merge.

"Many stars are part of a cosmic dance with a partner, orbiting each other in a binary system. They're not solitary giants but part of dynamic duos, interacting and influencing each other throughout their lifetimes," says Bethany Ludwig, a PhD student in in the David A. Dunlap Department of Astronomy & Astrophysics at the University Toronto and the third author on this paper. "Our work sheds light on these fascinating relationships, revealing a universe that is far more interconnected and active than we previously imagined."

"Just as humans are social beings, stars too, especially the massive ones, are rarely alone," Ludwig says.

As stars evolve and expand to become red giants, the hydrogen at the outer edges of one can be stripped by the gravitational pull of its companion -- leaving a very hot helium core exposed. The process can take tens of thousands, or even hundreds of thousands, of years.

Stripped stars are difficult to find because much of the light they emit is outside of the visible light spectrum and can be obstructed by dust in the universe or outshone by their companion stars.

Drout and her collaborators began their search in 2016. Having studied hydrogen-poor supernovae during her PhD, Drout set out to find the stripped stars thought to be at the heart of them during a NASA Hubble Postdoctoral Fellowship at the Observatories of the Carnegie Institution for Science. She met fellow co-author Ylva Götberg, now Assistant Professor at the Institute of Science and Technology Austria (ISTA), at a conference, who had recently built new theoretical models of what these stars should look like.

Drout, Götberg, and their collaborators designed a new survey to look in the ultraviolet part of the spectrum where extremely hot stars emit most of their light. While invisible to the naked eye, ultraviolet light can be detected by specialized instruments and telescopes.

Using data from the Swift Ultra-Violet/Optical Telescope, the researchers collected brightnesses for millions of stars in the Large and Small Magellanic Clouds, two of the closest galaxies to Earth. Ludwig developed the first wide-field UV catalog of the Magellanic Clouds and used UV photometry to detect systems with unusual UV emissions, signaling the possible presence of a stripped star.

They carried out a pilot study of 25 objects, obtaining optical spectroscopy with the Magellan Telescopes at Las Campanas Observatory between 2018 and 2022. They used these observations to demonstrate that the stars were hot, small, hydrogen-poor, and in binary systems -- all consistent with their model predictions.

Currently, the researchers are continuing to study the stars identified in this paper and expanding their search to find more. They will be looking both within nearby galaxies and within our own Milky Way with approved programs on the Hubble Space Telescope, the Chandra X-Ray Telescope, the Magellan Telescopes, and the Anglo-Australian Telescope. As part of this publication, all theoretical models and data used to identify these stars have been made public and available to other scientists.

Read more at Science Daily

Vervet monkeys follow different social 'norms' and respond to 'peer pressure,' new long-term study shows

People living in different communities follow different social customs or norms. In some places, for instance, it might be standard practice to greet each person you see on the street, while in others that simply isn't done. In some cases, such differences may even vary from one neighborhood to the next. Now researchers reporting in the journal iScience on December 19 have found similarly varied social traditions and styles among neighboring groups of vervet monkeys.

"We report the existence of behavioral traditions of social customs in vervet monkeys that are stable across 9 years," says Elena Kerjean of the University of Lausanne in Switzerland and Paul Sabatier University in Toulouse, France.

The researchers found that such differences in social traditions set up differences in "social atmosphere" that could be passed on from one generation to the next through social learning.

Intriguingly, they also found that dispersing males quickly adapted their social style to that of their new group, suggesting that they may experience a phenomenon akin to social conformity driven by peer pressure.

Kerjean and colleagues including Erica van de Waal and Charlotte Canteloup knew that other animals, like people, follow traditions.

But most studies had focused primarily on the presence or absence of traditions such as tool use.

They hadn't explored more subtle, quantitative differences in social behavior that can lead to important differences in a group's social atmosphere.

To explore further in the new study, the researchers analyzed more than 84,000 social interactions between almost 250 vervet monkey individuals collected over nine years in three neighboring groups.

Their analyses revealed an unexpected difference: in one of the groups, dubbed Ankhase (AK), the monkeys were more likely than in the other two groups to trade off when grooming each other.

"We found that individuals in one group -- AK -- display significantly more affiliative behaviors than in the two other groups, and this difference was stable over 9 years of study," Kerjean says.

The AK group was not only more social than the other two, but they also exchanged grooming more reciprocally.

When a monkey groomed another monkey, that monkey would usually repay the favor.

As a result, grooming was exchanged more fairly in AK compared to the other two groups.

"You can think about it like massage exchanges between individuals," Kerjean explained.

"If I give you a massage 100 times a year but you only did it two times, I may feel that our relation is quite unfair. That's the kind of differences we observed between our groups."

The researchers also found that six males who moved from one group to another adapted their social interactions to better match their new groups.

Those changes were also seen in both directions. Upon moving out of the AK group, males became less social and less likely to groom a partner fairly.

Males leaving one of the less social groups for AK showed exactly the opposite trend.

"Males adapted their sociality to the group they integrated with, which we believe is a good example of social conformity," Kerjean says.

"This normative rule -- act like others -- probably helps them to get better integrated in a new group. This conformity effect had been previously shown through a novel food experiment, but this is the first time that we observed that with social behavior."

The findings show that groups not only have different social traditions but that those traditions also can be stable over time in ways that are likely mediated socially.

The researchers suggest that these differences are passed on through social learning, although they can't rule out that there may be other differences in the environment at work, too.

Read more at Science Daily

Mysterious fruit shown to be the oldest known fossils of the Frankincense and Myrrh family

Early in the 1970s, a paleontologist working on the outskirts of an Indian village found small, bead-like fossils embedded in the gray chert dotting the surrounding fields. The site was notorious for turning up plant fossils that were difficult to identify, including the fruit of an extinct species resignedly given the name "Enigmocarpon." The new fossils proved just as frustratingly intractable; more of them were discovered in India over the next several decades, but scientists had little luck deciding what type of plant they belonged to.

Now, researchers say they've solved the mystery. Using CT scanning technology, Steven Manchester, curator of paleobotany at the Florida Museum of Natural History, created 3D reconstructions of the original fossil specimens and others collected since.

He showed these to a colleague, who noticed something odd about the five triangular seeds inside.

"When I showed him the 3D images, he said "those aren't seeds.

Pyrenes are woody dispersal pods that give seeds an extra layer of protection.

Examples include the hard stones at the cores of cherries, peaches, dates and pistachios, which prevent the seeds from being digested along with the rest of the fruit.

Distinguishing a seed from a pyrene, especially when they're the size of snowflakes, requires close scrutiny.

Traditional methods of paleobotany, which involve incrementally dissolving fossils in acid and observing each new layer under a microscope, had proven insufficient.

"If we had specimens that fractured at just the right plane, I would have been able to recognize them, but with the material we had on hand, I couldn't tell," Manchester said.

There are only a few plant groups that produce pyrenes, fewer still with fruits that contain five seeds arranged in a pentagram.

Through a process of elimination, Manchester and Judd determined the fossils belonged to an extinct species in Burseraceae, the Frankincense family.

Fossilized wood, leaves, fruits and flowers from this family have been found elsewhere in India, often sandwiched between thick slabs of basalt created by one of the largest volcanic eruptions in Earth's history.

At the time, India was an island off the southeast coast of Africa.

India's continental plate was slowly inching toward Europe and Asia, and as it rafted past Madagascar, it broke the seal on a thin layer of Earth's crust.

Rivers of liquid rock poured onto a landscape the size of California and Texas combined.

The eruptions occurred intermittently for nearly a million years, and they repeatedly killed any vegetation that grew during the interludes.

"The fossils were preserved at times of quiet between the eruptions," Manchester said.

"Ponds and lakes formed on the relatively fresh lava flows, and vegetation, including wood and seeds, were washed into them and covered by sediment."

The shield volcano responsible for the destruction was active just before and after the asteroid impact that drew the curtains on the Cretaceous, and both are thought to have contributed to the extinctions that followed.

Most fossils from the Frankincense family have, up until now, been recovered from rocks that postdate the asteroid impact.

The original fruits discovered in the 1970s were fossilized before that event.

This makes them the oldest Burseraceae fossils discovered to date, which has important implications for the family's origin.

Scientists have a good idea of when plants in the group initially evolved, but it's still unclear where they came from.

Ancient species of Burseraceae are a common component of fossil beds in southern England, the Czech Republic and parts of North America.

Beginning roughly 50 million years ago, however, Earth's climate began a long cooling process that ultimately resulted in the most recent Ice Ages.

As temperatures fell, species in the Frankincense family seemed to reverse their preference for hemispheres.

Today, there are more than 700 Burseraceae species, and most of them grow south of the equator.

The ancestors of modern Burseraceae species are thought to have first appeared somewhere in the north.

Alternatively, a few early species may have had a global distribution but became isolated as continents drifted apart.

The fossils from India suggest the southern hemisphere may have been the real birthplace of the family.

Read more at Science Daily

Snowflakes swirling in turbulent air as they fall through a laser light sheet

A winter wonderland calls to mind piles of fluffy, glistening snow. But to reach the ground, snowflakes are swept into the turbulent atmosphere, swirling through the air instead of plummeting directly to the ground.

The path of precipitation is complex but important to more than just skiers assessing the potential powder on their alpine vacation or school children hoping for a snow day.

Determining snowflake fall speed is crucial for predicting weather patterns and measuring climate change.

In Physics of Fluids, from AIP Publishing, researchers from the University of Utah report snowflake accelerations in atmospheric turbulence.

They found that regardless of turbulence or snowflake type, acceleration follows a universal statistical pattern that can be described as an exponential distribution.

"Even in the tropics, precipitation often starts its lifetime as snow," said author Timothy Garrett.

"How fast precipitation falls greatly affects storm lifetimes and trajectories and the extent of cloud cover that may amplify or diminish climate change. Just small tweaks in model representations of snowflake fall speed can have important impacts on both storm forecasting and how fast climate can be expected to warm for a given level of elevated greenhouse gas concentrations."

Set up in a ski area near Salt Lake City, the team battled an unprecedented 900 inches of snow.

They simultaneously filmed snowfall and measured atmospheric turbulence.

Using a device they invented that employs a laser light sheet, they gathered information about snowflake mass, size, and density.

"Generally, as expected, we find that low-density 'fluffy' snowflakes are most responsive to surrounding turbulent eddies," said Garrett.

Despite the system's complexity, the team found that snowflake accelerations follow an exponential frequency distribution with an exponent of three halves.

In analyzing their data, they also discovered that fluctuations in the terminal velocity frequency distribution followed the same pattern.

"Snowflakes are complicated, and turbulence is irregular. The simplicity of the problem is actually quite mysterious, particularly given there is this correspondence between the variability of terminal velocities -- something ostensibly independent of turbulence -- and accelerations of the snowflakes as they are locally buffeted by turbulence," said Garrett.

Because size determines terminal velocity, a possible explanation is that the turbulence in clouds that influences snowflake size is related to the turbulence measured at the ground.

Read more at Science Daily

Ringing in the holidays with ringed planet Uranus

NASA's James Webb Space Telescope recently trained its sights on unusual and enigmatic Uranus, an ice giant that spins on its side. Webb captured this dynamic world with rings, moons, storms, and other atmospheric features -- including a seasonal polar cap. The image expands upon a two-color version released earlier this year, adding additional wavelength coverage for a more detailed look.

With its exquisite sensitivity, Webb captured Uranus' dim inner and outer rings, including the elusive Zeta ring -- the extremely faint and diffuse ring closest to the planet.

It also imaged many of the planet's 27 known moons, even seeing some small moons within the rings.

In visible wavelengths as seen by Voyager 2 in the 1980s, Uranus appeared as a placid, solid blue ball.

In infrared wavelengths, Webb is revealing a strange and dynamic ice world filled with exciting atmospheric features.

One of the most striking of these is the planet's seasonal north polar cloud cap.

Compared to the Webb image from earlier this year, some details of the cap are easier to see in these newer images.

These include the bright, white, inner cap and the dark lane in the bottom of the polar cap, toward the lower latitudes.

Several bright storms can also be seen near and below the southern border of the polar cap.

The number of these storms, and how frequently and where they appear in Uranus's atmosphere, might be due to a combination of seasonal and meteorological effects.

The polar cap appears to become more prominent when the planet's pole begins to point toward the Sun, as it approaches solstice and receives more sunlight.

Uranus reaches its next solstice in 2028, and astronomers are eager to watch any possible changes in the structure of these features.

Webb will help disentangle the seasonal and meteorological effects that influence Uranus's storms, which is critical to help astronomers understand the planet's complex atmosphere.

Because Uranus spins on its side at a tilt of about 98 degrees, it has the most extreme seasons in the solar system.

For nearly a quarter of each Uranian year, the Sun shines over one pole, plunging the other half of the planet into a dark, 21-year-long winter.

With Webb's unparalleled infrared resolution and sensitivity, astronomers now see Uranus and its unique features with groundbreaking new clarity.

These details, especially of the close-in Zeta ring, will be invaluable to planning any future missions to Uranus.

Read more at Science Daily

Mesopotamian bricks unveil the strength of Earth's ancient magnetic field

Ancient bricks inscribed with the names of Mesopotamian kings have yielded important insights into a mysterious anomaly in Earth's magnetic field 3,000 years ago, according to a new study involving UCL researchers.

The research, published in the Proceedings of the National Academy of Sciences (PNAS), describes how changes in the Earth's magnetic field imprinted on iron oxide grains within ancient clay bricks, and how scientists were able to reconstruct these changes from the names of the kings inscribed on the bricks.

The team hopes that using this "archaeomagnetism," which looks for signatures of the Earth's magnetic field in archaeological items, will improve the history of Earth's magnetic field, and can help better date artefacts that they previously couldn't.

Co-author Professor Mark Altaweel (UCL Institute of Archaeology) said: "We often depend on dating methods such as radiocarbon dates to get a sense of chronology in ancient Mesopotamia. However, some of the most common cultural remains, such as bricks and ceramics, cannot typically be easily dated because they don't contain organic material. This work now helps create an important dating baseline that allows others to benefit from absolute dating using archaeomagnetism."

The Earth's magnetic field weakens and strengthens over time, changes which imprint a distinct signature on hot minerals that are sensitive to the magnetic field.

The team analysed the latent magnetic signature in grains of iron oxide minerals embedded in 32 clay bricks originating from archaeological sites throughout Mesopotamia, which now overlaps with modern day Iraq.

The strength of the planet's magnetic field was imprinted upon the minerals when they were first fired by the brickmakers thousands of years ago.

At the time they were made, each brick was inscribed with the name of the reigning king which archaeologists have dated to a range of likely timespans.

Together, the imprinted name and the measured magnetic strength of the iron oxide grains offered a historical map of the changes to the strength of the Earth's magnetic field.

The researchers were able to confirm the existence of the "Levantine Iron Age geomagnetic Anomaly," a period when Earth's magnetic field was unusually strong around modern Iraq between about 1050 to 550 BCE for unclear reasons.

Evidence of the anomaly has been detected as far away as China, Bulgaria and the Azores, but data from within the southern part of the Middle East itself had been sparse.

Lead author Professor Matthew Howland of Wichita State University said: "By comparing ancient artefacts to what we know about ancient conditions of the magnetic field, we can estimate the dates of any artifacts that were heated up in ancient times."

To measure the iron oxide grains, the team carefully chipped tiny fragments from broken faces of the bricks and used a magnetometer to precisely measure the fragments.

By mapping out the changes in Earth's magnetic field over time, this data also offers archaeologists a new tool to help date some ancient artefacts.

The magnetic strength of iron oxide grains embedded within fired items can be measured and then matched up to the known strengths of Earth's historic magnetic field.

The reigns of kings lasted from years to decades, which offers better resolution than radiocarbon dating which only pinpoints an artefact's date to within a few hundred years.

An additional benefit of the archaeomagnetic dating of the artefacts is it can help historians more precisely pinpoint the reigns of some of the ancient kings that have been somewhat ambiguous.

Though the length and order of their reigns is well known, there has been disagreement within the archaeological community about the precise years they took the throne resulting from incomplete historical records.

The researchers found that their technique lined up with an understanding of the kings' reigns known to archaeologists as the "Low Chronology."

The team also found that in five of their samples, taken during the reign of Nebuchadnezzar II from 604 to 562 BCE, the Earth's magnetic field seemed to change dramatically over a relatively short period of time, adding evidence to the hypothesis that rapid spikes in intensity are possible.

Read more at Science Daily

Can we decode the language of our primate cousins?

Are we able to differentiate between the vocal emissions of certain primates? A team from the University of Geneva (UNIGE) asked volunteers to categorise the vocalisations of three species of great apes (Hominidae) and humans. During each exposure to these ''onomatopoeia'', brain activity was measured. Unlike previous studies, the scientists reveal that phylogenetic proximity -- or kinship -- is not the only factor influencing our ability to identify these sounds. Acoustic proximity -- the type of frequencies emitted -- is also a determining factor. These results show how the human brain has evolved to process the vocal emissions of some of our closest cousins more efficiently. Find out more in the journal Cerebral Cortex Communications.

Our ability to process verbal language is not based solely on semantics, i.e. the meaning and combination of linguistic units.

Other parameters come into play, such as prosody, which includes pauses, accentuation and intonation.

Affective bursts -- ''Aaaah!'' or ''Oh!'' for example -- are also part of this, and we share these with our primate cousins.

They contribute to the meaning and understanding of our vocal communications.

When such a vocal message is emitted, these sounds are processed by the frontal and orbitofrontal regions of our brain.

The function of these two areas is, among other things, to integrate sensory and contextual information leading to a decision.

Are they activated in the same way when we are exposed to the emotional vocalisations of our close cousins the chimpanzees, macaques and bonobos?

Are we able to differentiate between them?

MRI scans with headphones on

A UNIGE team sought to find out by exposing a group of 25 volunteers to various human and simian vocalisations.

''The participants were placed in an MRI scanner and were given headphones.

After a short period of familiarisation with the different types of vocalisations, each participant had to categorise them, i.e. identify to which species they belonged,'' explains Leonardo Ceravolo, senior lecturer at the UNIGE's Faculty of Psychology and Educational Sciences, and first author of the study.

These vocalisations were of the affiliative type, i.e. linked to a positive interaction, or of the agonistic type, i.e. linked to a threat or distress.

The human vocalisations came from databases recorded by actors.

The simian ones came from field recordings made as part of previous research.

This study is the first of its kind to include bonobo vocalisations.

Bonobos, not so close cousins

The results show that for macaque and chimpanzee vocalisations, the frontal and orbitofrontal regions of the participants were activated in a similar way to human vocalisations.

The participants were able to differentiate between them easily.

On the other hand, when confronted with the ''sounds'' of bonobos, also close cousins of humans, the involved cerebral areas were much less activated, and categorisation was at chance level.

''It was thought that kinship between species -- the 'phylogenetic distance' -- was the main parameter for having the ability, or not, to recognise these different vocalisations.

We thought that the closer we were genetically, the more important this ability was,'' explains Didier Grandjean, full professor at the Swiss Center for Affective Sciences and at the UNIGE's Faculty of Psychology and Educational Sciences, who led the study.

''Our results show that a second parameter comes into play: acoustic distance.

The further the dynamics of the acoustic parameters, such as the frequencies used, are from those of humans, the less certain frontal regions are activated.

Read more at Science Daily

This next generation blue light could potentially promote or hinder sleep on command

Blue light from LED lamps and consumer electronics can mess with your sleep because it disrupts production of the natural sleep hormone melatonin. Tinted glasses or displays in night mode can mask, but don't remove, a portion of the disruptive wavelengths. But now, researchers report in ACS Omega that they have designed more "human-centric" LEDs that could potentially enhance drowsiness or alertness on command.

Humans have evolved over millennia to be active during the day and to rest at night; we've depended on the sun to regulate our sleep/wake cycle.

But many people today spend a majority of their time indoors, shielded from the sun, so it's harder for them to maintain that optimal 24-hour circadian rhythm.

Exposure to artificial light can worsen this problem because it can decrease secretion of melatonin.

And nighttime exposure to blue light, specifically, is notorious for interfering with melatonin production and therefore sleep.

However, blue light is emitted by LEDs in lamps, computers, TVs, phones and other handheld electronics that people often use at night.

So, Changwook Kim, Young Rag Do and colleagues set out to make a light source that could support natural circadian rhythms, no matter what time of day it is used.

Blue light ranges in wavelength from 380 to 500 nanometers (nm), but not all blue light is created equal.

The wavelengths that suppress melatonin production -- and cause wakefulness -- are in the range of 460 to 500 nm. So, the researchers designed two LEDs that emitted different wavelengths of blue light.

One LED, intended for daytime use, restricted its blue emissions to wavelengths close to 475 nm. The other LED, for evening use, emitted blue wavelengths near 450 nm, outside the range that disturbs sleep.

Then the researchers built these two new LEDs into bulbs. Like conventional bulbs, they produced white light by converting some of the blue light into red and green with the help of phosphors encased in the bulbs.

The new LED bulbs were placed along with conventional LED bulbs in fixtures installed in the ceiling of a windowless room furnished with a desk, treadmill and bed.

Individual male volunteers stayed in the room for a stretch of three days.

A computer controlled which type of LED was turned on or off during their stay; that way, the researchers could compare the impact on melatonin levels of conventional bulbs versus the new daytime and evening bulbs.

Saliva samples from 22 volunteers showed that using the new LEDs increased the participants' nighttime melatonin levels by 12.2% and reduced daytime melatonin by 21.9% compared to consistent conventional LED exposure.

The researchers hope manufacturers of LED lamps and electronic displays can apply these findings to help people increase daytime vitality and work efficiency while also improving nighttime relaxation and sleep quality.

Read more at Science Daily

Reaching for the (invisible) stars

Supernovae-stellar explosions as bright as an entire galaxy-have fascinated us since time immemorial. Yet, there are more hydrogen-poor supernovae than astrophysicists can explain. Now, a new Assistant Professor at the Institute of Science and Technology Austria (ISTA) has played a pivotal role in identifying the missing precursor star population. The results, now published in Science, go back to a conversation the involved professors had many years ago as junior scientists.

Some stars do not simply die down, but explode in a stellar blast that could outshine entire galaxies. These cosmic phenomena, called supernovae, spread light, elements, energy, and radiation in space and send galactic shock waves that could compress gas clouds and generate new stars. In other words, supernovae shape our universe. Among these, hydrogen-poor supernovae from exploding massive stars have long puzzled astrophysicists. The reason: scientists have not been able to put their finger on their precursor stars. It is almost as if these supernovae appeared out of nowhere.

"There are many more hydrogen-poor supernovae than our current models can explain. Either we can't detect the stars that mature on this path, or we must revise all our models," says ISTA Assistant Professor Ylva Götberg. She pioneered this work together with Maria Drout, an Associated Faculty Member of the Dunlap Institute for Astronomy & Astrophysics, University of Toronto, Canada. "Single stars would typically explode as hydrogen-rich supernovae. Being hydrogen-poor indicates that the precursor star must have lost its thick hydrogen-rich envelope. This happens naturally in a third of all massive stars through envelope stripping by a binary companion star," says Götberg. Now, Götberg and Drout combined their areas of expertise in theoretical modeling and observation to hunt down the missing stars. Their quest is successful: they document a first-of-its-kind star population that finally bridges a large knowledge gap and sheds light on the origin of hydrogen-poor supernovae.

Binary stars and envelope stripping

The stars that Götberg and Drout search for go in pairs: interlocked in a binary star system. Some binary systems are well-known to us Earthlings: these include the brightest star in our night sky, Sirius A, and its faint companion star Sirius B. The Sirius binary system is located only 8.6 light-years away from Earth-a stone's throw in cosmic terms. This explains Sirius A's observed brightness in our night sky.

Astrophysicists expect the missing stars to be initially formed from massive binary systems. In a binary system, the stars would orbit around one another until the more massive star's thick, hydrogen-rich envelope expands. Eventually, the expanding envelope experiences a stronger gravitational pull to the companion star than to its own core. This causes a transfer of mass to begin, which eventually leads the entire hydrogen-rich envelope to be stripped off, leaving the hot and compact helium core exposed-more than 10 times hotter than the Sun's surface. This is precisely the type of stars that Götberg and Drout are looking for. "Intermediate mass helium stars stripped through binary interaction are predicted to play important roles in astrophysics. Yet, they were not observed until now," says Götberg. In fact, there is an important mass gap between the known classes of helium stars: the more massive Wolf-Rayet (WR) stars have more than 10 times the Sun's mass, and the low-mass subdwarf stars could have around half the Sun's mass. However, models have predicted the precursors of hydrogen-poor supernovae to lie between 2 and 8 solar masses following stripping.

Not just a needle in the haystack

Before Götberg and Drout's study, only one star was found to fulfill the expected mass and composition criteria and was called "Quasi-WR" (or "Almost Wolf-Rayet"). "Yet, the stars that follow this path have such a long lifetime that many must be scattered all over the observable universe," says Götberg. Did the scientists simply not "see" them? Thus, Götberg and Drout drew on their complementary expertise. With the help of UV photometry and optical spectroscopy, they identified a population of 25 stars that are consistent with the expectations for intermediate-mass helium stars. The stars are located in two well-studied neighboring galaxies, the Large and the Small Magellanic Clouds. "We showed that these stars were bluer than the stellar birthline, the bluest phase in a single star's lifetime. Single stars mature by evolving towards the redder region of the spectrum. A star only shifts in the opposite direction if its outer layers are removed-something that is expected to be common in interacting binary stars and rare among single massive stars," explains Götberg.

The scientists then verified their candidate star population using optical spectroscopy: they showed that the stars had strong spectral signatures of ionized helium. "Strong ionized helium lines tell us two important things: first, they confirm that the stars' outermost layers are dominated by helium and, second, that their surface is very hot. This is what happens to stars left as an exposed, compact, helium-rich core following stripping," says Götberg. Yet, both stars in a binary system contribute to the observed spectra. Thus, this technique allowed the researchers to classify their candidate population depending on which star contributed the most to the spectrum. "This work allowed us to find the missing population of intermediate-mass, stripped helium stars, the predicted progenitors of hydrogen-poor supernovae. These stars have always been there and there are probably many more out there. We must simply come up with ways to find them," says Götberg. "Our work may be one of the first attempts, but there should be other ways possible."

From graduate students at a conference to group leaders

The idea behind this project sparked in a discussion following a talk by Götberg at a conference that she and Drout attended during their graduate studies. Both scientists, then Early Career Researchers reaching for the stars, are now group leaders in their field. Götberg joined ISTA in September following her research at the Carnegie Observatories in Pasadena, California, as a NASA Hubble postdoctoral fellow. At ISTA, Götberg joins the Institute's growing ranks of young group leaders in astrophysics and leads her own group focused on studying the binary interactions of stars.

Read more at Science Daily

Can you change a chicken into a frog, a fish or a chameleon?

Gastrulation is one of the most important phases in early embryonic development. Before gastrulation, vertebrate embryos are simple two-dimensional sheets of cells. By the end of gastrulation, an embryo will have begun to differentiate distinct cell types, set up the basic axes of the body and internalize some of the precursors for organs in a three-dimensional structure. Amniotes, like chickens and humans, will have developed a primitive streak, the precursor to the brain and skin, while fish and amphibians will have developed a spherical-shaped blastopore.

Gastrulation is a feat of self-organization, requiring the ballet-like coordinated movements of hundreds to tens of thousands of cells.

But, despite its importance in development, scientists only partially understand the underlying mechanisms that coordinate this large-scale movement of cells.

Now a team of researchers from the Harvard, the University of California San Diego and the University of Dundee in the U.K., have developed a theoretical framework that can reproduce and predict the patterns associated with gastrulation in a chicken embryo.

Building on their experimental findings published earlier this year in Science Advances, and using a combination of theory and experiment, the researchers demonstrated that small changes in cell parameters and behavior can have a dramatic impact on the resulting gastrulation patterns.

The new research was also published in Science Advances.

"Linking the developmental processes underlying morphogenesis in an organism to the variations of these same processes across evolution is an old question in biology," said L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), and Professor of Organismic and Evolutionary Biology, and of Physics in the Faculty of Arts and Sciences (FAS) and senior author of the paper.

"Moving away from the gene-centric molecular focus on this question, we asked if there are emergent biophysical principles that operate on the multi-cellular level and can help explain the self-organized gastrulation patterns from both a developmental and an evolutionary perspective."

Working closely with experimentalists, the researchers developed a theoretical and computational model that could recreate the movement of the epithelial layer of cells in chick embryos during gastrulation.

The team then identified two parameters -- one related to the initial distribution of cells in an embryo and the other related to cell behavior -- to tweak during gastrulation.

"When we changed these two parameters in the model, which was only informed by the mechanisms of chick development, it remarkably showed gastrulation patterns naturally seen in other species," said Mattia Serra, first author of the paper and former Schmidt Science fellow in the Mahadevan group.

Serra is an Assistant Professor in Physics at UC San Diego.

Consistent with the computational results, experiments show that perturbing the same parameters in vivo in a chick embryo caused the chick to form a disk-like blastopore, seen in frogs, a ring-like circular primitive streak, like those seen in fish, or an elongated elliptical canal-like streak seen in chameleon.

"Our work suggests that the general biophysical principles underlying active self-organized flows and forces during embryogenesis have the power to explain developmental processes and their evolutionary variations across different species of vertebrates," said Mahadevan.

"We were surprised to see how simple mechanochemical rules could predict highly distinct coherent flows of thousands of cells measured in a living chick embryo," said Serra.

This research not only sheds light on the principles for self- organization in early development but could also help researchers understand the evolutionary history of developmental processes and suggest ways to control the development of synthetic organoids.

This research looked at the early stages of development, when the embryo is just transforming from two-dimensions into three.

Next, Mahadevan wants to understand what happens when the embryo starts to fold and buckle to create the more complex shapes of organs and eventually whole organisms.

"Using our knowledge of developmental processes at the molecular and cellular level, we eventually hope to provide an integrated framework for how cells form into tissues and tissues into organs, towards a better understanding of morphogenesis," said Mahadevan.

Read more at Science Daily

Coevolution helps Santa's reindeer feast after flight

When Santa's exhausted reindeer finally set down their sleigh in the deep snow of the North Pole early Christmas morning, it's not Rudolph's radiant red nose that will help them find sustenance in the barren landscape.

Instead, researchers from Dartmouth and the University of St. Andrews in Scotland report that the eyes of Rudolph and his reindeer brethren may have evolved so that they can spot their favorite food during dark and snowy Arctic winters, according to a new study in the journal i-Perception.

The findings help explain the long-standing scientific mystery as to why reindeer can see light in the ultraviolet (UV) spectrum -- and add intrigue to the smiling airborne ungulates popularized in the classic story by 1926 Dartmouth graduate Robert L. May.

"Reindeer are so cool, but many people think about them only at Christmas," Nathaniel Dominy, first author of the study and the Charles Hansen Professor of Anthropology at Dartmouth says.

"Now is a good time to alert people to their extraordinary visual system."

Reindeer subsist primarily on reindeer moss, or Cladonia rangiferina, which isn't a moss but actually a species of algae-fungus fusion known as lichen.

C. rangiferina forms thick crunchy carpets across northern latitudes and is so integral to the survival of reindeer that even its formal name stems from the scientific term for reindeer, Rangifer.

The researchers worked in the Cairngorms mountains in the Scottish Highlands, which host Britain's only reindeer herd -- reintroduced from Scandinavia after being hunted to extinction locally -- and more than 1,500 species of lichen.

Despite these options, reindeer in the Cairngorms rely on C. rangiferina during the winter.

"A peculiar trait of reindeer is their reliance on this one type of lichen," Dominy says.

"It's unusual for an any animal to subsist so heavily on lichens, let alone such a large mammal."

To the human eye, the white lichen is invisible against the snowy backdrop of an Arctic winter.

But Dominy and co-authors Catherine Hobaiter and Julie Harris from St. Andrews discovered that C. rangiferina and a few other lichen species that supplement the reindeer diet absorb UV light.

Spectral data from the lichen and light filters calibrated to mimic reindeer vision revealed that these organisms appear to reindeer as dark patches against an otherwise brilliant landscape, making them easier to locate.

"Getting a visual approximation of how reindeer might see the world is something other studies haven't done before," says Dominy, who published a paper in 2015 on how Rudolph's red nose would've acted as an effective foglamp in the haze of winter.

"If you can put yourself in their hooves looking at this white landscape, you would want a direct route to your food," he says.

"Reindeer don't want to waste energy wandering around searching for food in a cold, barren environment. If they can see lichens from a distance, that gives them a big advantage, letting them conserve precious calories at a time when food is scarce."

Previous research has shown that reindeer eyes change between summer and winter, Dominy says.

Their tapetum -- the light-enhancing membrane that gives many animals "shiny" eyes -- transitions in winter from the golden color most animals have to a vivid blue that is thought to amplify the low light of polar winter.

"If the color of the light in the environment is primarily blue, then it makes sense for the eye to enhance the color blue to make sure a reindeer's photoreceptors are maximizing those wavelengths," Dominy says.

But the blue tapetum also lets up to 60% of ultraviolet light pass through to the eye's color sensors.

That means that reindeer see the winter world as a shade of purple, similar to how a person would see a room with a black light -- UV-reflecting surfaces such as snow shine brightly while UV-absorbing surfaces are starkly dark.

The researchers recount how scientists have sought to answer why the eyes of an Arctic animal that is active during the day would be receptive to the UV light that would be reflecting off of every snow-covered surface.

But their study suggests that the answer is tied to what UV light doesn't reflect from -- C. rangiferina and other bushy lichens.

Given the importance of lichens in the reindeer diet, the researchers report, it is possible that the animal's eyes are optimized to single out this food staple at the time of year it would be most difficult to find.

Read more at Science Daily

Researchers, Coast Salish people analyze 160-year-old indigenous dog pelt in the Smithsonian's collection

Researchers from the Smithsonian's National Museum of Natural History led a new analysis that sheds light on the ancestry and genetics of woolly dogs, a now extinct breed of dog that was a fixture of Indigenous Coast Salish communities in the Pacific Northwest for millennia. Anthropologist Logan Kistler and evolutionary molecular biologist Audrey Lin analyzed genetic clues preserved in the pelt of "Mutton," the only known woolly dog fleece in the world, to pinpoint the genes responsible for their highly sought-after woolly fur.

The study's findings, published today, Dec. 14, in the journal Science, include interviews contributed by several Coast Salish co-authors, including Elders, Knowledge Keepers and Master Weavers, who provided crucial context about the role woolly dogs played in Coast Salish society.

"Coast Salish traditional perspective was the entire context for understanding the study's findings," said Kistler, the museum's curator of archaeobotany and archaeogenomics.

Coast Salish tribal nations in Washington state and British Columbia bred and cared for woolly dogs for thousands of years. Prized for their thick undercoats, the dogs were sheared like sheep and often kept in pens or on islands to carefully manage their breeding and to care for the canines' health and vitality. Coast Salish weavers used the dogs' wool to craft blankets and other woven items that served a variety of ceremonial and spiritual purposes. Woolly dogs themselves possessed spiritual significance and were often treated as beloved family members. As emblems for many Coast Salish communities, woolly dogs adorned woven baskets and other art forms.

By the mid-19th century, this once thriving dog wool-weaving tradition was in decline. In the late 1850s, naturalist and ethnographer George Gibbs cared for a woolly dog named Mutton. When Mutton died in 1859, Gibbs sent his pelt to the nascent Smithsonian Institution, where the fleece has resided ever since. However, few were aware of the pelt's existence until it was rediscovered in the early 2000s.

Lin first learned about Mutton when she was a Peter Buck postdoctoral fellow at the museum in 2021.

"When I saw Mutton in person for the first time, I was just overcome with excitement," said Lin, who is now a postdoctoral researcher at the American Museum of Natural History. "I had heard from some other people that he was a bit scraggly, but I thought he was gorgeous."

She was surprised to find out that virtually no work had been done on the genetics of woolly dogs, which disappeared around the turn of the 20th century. She teamed up with Kistler and they reached out to several Coast Salish communities to gauge their interest in working together on a potential research project on woolly dogs.

Many in the Coast Salish communities were eager to share their knowledge.

"We were very excited to participate in a study that embraces the most sophisticated Western science with the most established Traditional Knowledge," said Michael Pavel, an Elder from the Skokomish/Twana Coast Salish community in Washington, who remembers hearing about woolly dogs early in his childhood. "It was incredibly rewarding to contribute to this effort to embrace and celebrate our understanding of the woolly dog."

To complement the perspectives they received from Pavel and other Coast Salish people from British Columbia and Washington state (the text from their interviews is available in the study's supplementary materials), Lin, Kistler and their colleagues began analyzing Mutton's genetic code. They sequenced the woolly dog genome and compared it with the genomes of ancient and modern breeds of dogs to determine what set woolly dogs apart. They also identified certain chemical signatures called isotopes in Mutton's pelt to determine the dog's diet and teamed up with noted natural history illustrator Karen Carr to create a life-like reconstruction of what Mutton looked like in the 1850s. Carr's work is the first in-depth reconstruction of a Coast Salish woolly dog in nearly three decades.

Based on the genetic data, the team estimated that woolly dogs diverged from other breeds up to 5,000 years ago -- a date that lines up with archaeological remains from the region. They also discovered that Mutton was genetically similar to pre-colonial dogs from Newfoundland and British Columbia. The researchers estimate that nearly 85% of Mutton's ancestry can be linked to pre-colonial dogs. This ancient ancestry is surprising because Mutton lived decades after the introduction of European dog breeds. This makes it likely that Coast Salish communities continued to maintain woolly dogs' unique genetic makeup until right before the dogs were wiped out.

In total, the team analyzed more than 11,000 different genes in Mutton's genome to determine what gave woolly dogs their fluffy fleece and wool fibers that could be spun together to create yarn. They identified 28 genes that have links to hair growth and follicle regeneration. These included a gene that causes a woolly hair phenotype in humans, and another linked to curly hair in other dogs. Similar genes were even activated in the genomes of woolly mammoths.

However, Mutton's genetics could tell the researchers little about what caused the dogs to decline. Traditionally, scholars have speculated that the arrival of machine-made blankets to the region in the early 19th century made woolly dogs expendable. But insights from Pavel and other traditional experts revealed that it was improbable that such a central part of Coast Salish society could be replaced.

Instead, woolly dogs were likely doomed by numerous factors impacting the Coast Salish tribal nations after European settlers arrived. Due to disease and colonial policies of cultural genocide, displacement and forced assimilation, it likely became increasingly difficult or forbidden for Coast Salish communities to maintain their woolly dogs.

"It was thousands of years of very careful maintenance lost within a couple of generations," Lin said.

But despite their disappearance, the memory of woolly dogs is still embedded into Coast Salish society. And Pavel thinks their understanding of woolly dogs is only getting clearer thanks to the new research effort.

"All of our communities held a certain aspect of knowledge about the woolly dog," Pavel said. "But when woven together, as a result of participating in this study, we now have a much more complete understanding."

Read more at Science Daily

Scientists measure the distance to stars by their music

For most of us, the countless bright spots in the nighttime sky all seem to be stars. But in fact, some of those spots are actually planets, or distant suns, or even entire galaxies located billions of light years away. Just what you're looking at depends on how far it is from Earth. That's why measuring the exact distance to celestial objects is such an important goal for astronomers -- and one of the biggest challenges they're currently tackling.

It was with this in mind that the European Space Agency (ESA) launched the Gaia mission ten years ago.

Data collected by the Gaia satellite are opening up a window into the near Universe, providing astronomic measurements -- such as position, distance from the Earth and movement -- on nearly two billion stars.

At EPFL, the Standard Candles and Distances research group headed by Prof.

Richard Anderson is aiming to measure the current expansion of the Universe and sees Gaia as a valuable tool.

"Gaia increased by a factor of 10,000 the number of stars whose parallaxes are measured thanks to a massive gain in accuracy over its predecessor, the ESA Hipparcos mission," he says.

Today, scientists use parallaxes to calculate the distance to stars.

This method involves measuring parallax angles, with the help of the satellite, through a form of triangulation between Gaia's location in space, the Sun and the star in question.

The farther away a star, the more difficult the measurement because parallax gets smaller the larger the distance.

Despite the resounding success of Gaia, the measurement of parallax is complex, and there remain small systematic effects that must be checked and corrected in order for Gaia parallaxes to reach their full potential.

This is what scientists from EPFL and the University of Bologna, in Italy, have been working on, through calculations performed on over 12,000 oscillating red giant stars* -- the biggest sample size and most accurate measurements to date.

"We measured the Gaia biases by comparing the parallaxes reported by the satellite with parallaxes of the same stars that we determined using asteroseismology," says Saniya Khan, a scientist in Anderson's research group and the lead author of a study published today in Astronomy & Astrophysics.

Stellar earthquakes

In the same way that geologists study the Earth's structure using earthquakes, astronomers use asteroseismology, and specifically stars' vibrations and oscillations, to glean information about their physical properties.

Stellar oscillations are measured as tiny variations in light intensity and translated into sound waves, giving rise to a frequency spectrum of these oscillations.

"The frequency spectrum lets us determine how far away a star is, enabling us to obtain asteroseismic parallaxes," says Khan.

"In our study, we listened to the 'music' of a vast number of stars -- some of them 15,000 light-years away!"

To turn sounds into distance measurements, the research team started with a simple fact.

The speed with which sound waves propagate across space depends on the temperature and density of the star's interior.

"By analyzing the frequency spectrum of stellar oscillations, we can estimate the size of a star, much like you can identify the size of a musical instrument by the kind of sound it makes -- think of the difference in pitch between a violon and a cello," says Andrea Miglio, a full professor at the University of Bologna's Department of Physics and Astronomy and the study's third author.

Sophisticated analyses

Having thus calculated a star's size, the astronomers then determined its luminosity and compared this figure to the luminosity perceived here on Earth.

They coupled this information with temperature and chemical-composition readings obtained from spectroscopy and ran these data through sophisticated analyses to calculate the distance to the star.

Finally, the astronomers compared the parallaxes obtained in this process with those reported by Gaia in order to check the accuracy of the satellite's measurements.

"Asteroseismology is the only way we can check Gaia's parallax accuracy across the full sky -- that is, for both low- and high-intensity stars," says Anderson.

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Beef farming that keeps cattle on lifelong grass diets may have higher carbon footprint

Beef operations that keep cattle on lifelong grass-based diets may have an overall higher carbon footprint than those that switch cattle to grain-based diets partway through their lives. Daniel Blaustein-Rejto of the Breakthrough Institute, USA, and colleagues present these findings in the open-access journal PLOS ONE on December 13.

Cattle on lifelong grass diets are known as "pasture finished," while those that switch from grass to grain before slaughter are "grain finished." Prior research has suggested that pasture-finished beef operations have a higher carbon footprint than grain-finished operations.

However, most studies have limited their focus to the amount of greenhouse gases emitted directly by beef production without considering other factors that may affect the overall carbon footprint.

To help deepen understanding, Blaustein-Rejto and colleagues calculated and compared the carbon footprint of 100 beef operations located in 16 countries.

In addition to direct greenhouse gas emissions, their calculations incorporated soil carbon sequestration -- the capture and long-term storage in pasture soils of atmospheric carbon, often in the form of dead plants and cattle waste.

They also accounted for the carbon opportunity cost -- the carbon that would have been sequestered if the land had native ecosystems instead of being used for beef production.

Extensive statistical analysis showed that the pasture-finished operations produce 20 percent more greenhouse gases than grain-finished operations -- in line with prior studies.

However, after incorporating soil carbon sequestration and carbon opportunity cost, the total carbon footprint of pasture-finished operations was 42 percent higher, likely due to its more intense usage of land.

Further analysis suggested that an increase in land use intensity is indeed strongly associated with a bigger overall carbon footprint for beef operations.

The calculations also suggest that, averaging across all operations in the study, carbon opportunity costs may contribute even more to an operation's overall carbon footprint than its direct greenhouse gas emissions.

The researchers say their findings emphasize the need for climate mitigation efforts to account for carbon opportunity costs of beef production.

With pasture-finished beef often being seen as more premium, carbon footprint data may also provide important additional information to aid consumer choice.

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AI provides more accurate analysis of prehistoric and modern animals, painting picture of ancient world

A new Rice University study of the remains of prehistoric and modern African antelopes found that AI technology accurately identified animals more than 90% of the time compared to humans, who had much lower accuracy rates depending on the expert.

Composite images of teeth from five different antelope tribes analyzed and identified by artificial intelligence.

Photo courtesy of Manuel Domínguez-Rodrigo.

Identifying these animals and their habits helps paint a broader picture of ancient ecosystems, and with the assistance of this new technology, it can be done with more speed and accuracy than previously done by paleontologists, according to the study.

"African bovid tribe classification using transfer learning and computer vision" appeared in a recent edition of Annals of the New York Academy of Sciences.

The study outlines the groundbreaking AI technology used to analyze prehistoric livestock remains.

So why does it matter how these ancient animals lived and what they ate?

According to Manuel Domínguez-Rodrigo, visiting professor of anthropology at Rice, co-director of Madrid's Institute of Evolution in Africa and professor of prehistory at the University of Alcalá in Spain, the study sheds light on how the ecology of the time affected the evolution of mammal communities including humans, who over the past two million years have become highly dependent on other mammals.

"The evolution of ecosystems in Africa is of major relevance to understand what shaped our own evolution as humans," Domínguez-Rodrigo said.

"Our prehistoric ancestors were highly dependent on resources available in different habitats of African savanna ecosystems. Using fossil mammals -- highly specialized in their adaptations to different habitats -- to reconstruct these landscapes has been the most used method to interpret their ecology. Identifying those mammals by their teeth has not always been straightforward and was subjected to a high degree of expert knowledge and bias. Now we can do that with much more confidence. This will enable us to understand past environments but also understand better modern landscapes too when documenting the dead animals that they still contain."

And thanks to this technology, whose application to paleobiology is pioneered in Domínguez-Rodrigo's lab, he says archaeologists can now analyze information far more quickly and accurately than before.

"These AI methods are a revolution for the studies of paleobiology and human evolution in particular," he said.

"They provide an objective, replicable way of identifying animals, including the degree of confidence with which identifications are made."

Domínguez-Rodrigo said the success of AI in other fields, such as image-based medicine, was a proof of concept for its widespread application to other fields.

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'Long flu' has emerged as a consequence similar to long COVID

Since the COVID-19 pandemic began, extensive research has emerged detailing the virus's ability to attack multiple organ systems, potentially resulting in a set of enduring and often disabling health problems known as long COVID. Now, new research from Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care System indicates that people hospitalized with seasonal influenza also can suffer long-term, negative health effects, especially involving their lungs and airways.

The new study comparing the viruses that cause COVID-19 and the flu also revealed that in the 18 months after infection, patients hospitalized for either COVID-19 or seasonal influenza faced an increased risk of death, hospital readmission, and health problems in many organ systems. Further, the time of highest risk was 30 days or later after initial infection.

"The study illustrates the high toll of death and loss of health following hospitalization with either COVID-19 or seasonal influenza," said senior author Ziyad Al-Aly, MD, a clinical epidemiologist at Washington University. "It's critical to note that the health risks were higher after the first 30 days of infection. Many people think they're over COVID-19 or the flu after being discharged from the hospital. That may be true for some people. But our research shows that both viruses can cause long-haul illness."

The findings are published Dec. 14 in The Lancet Infectious Diseases.

The statistical analysis spanned up to 18 months post-infection and included a comparative evaluation of risks of death, hospital admissions and 94 adverse health outcomes involving the body's major organ systems.

"A review of past studies on COVID-19 versus the flu focused on a short-term and narrow set of health outcomes," said Al-Aly, who treats patients within the VA St. Louis Health Care System and is an assistant professor of medicine at Washington University. "Our novel approach compared the long-term health effects of a vast array of conditions. Five years ago, it wouldn't have occurred to me to examine the possibility of a 'long flu.' A major lesson we learned from SARS-CoV-2 is that an infection that initially was thought to only cause brief illness also can lead to chronic disease. This revelation motivated us to look at long-term outcomes of COVID-19 versus flu.

"We wanted to know whether and to what degree people with flu also experience long-term health effects," Al-Aly said. "The big answer is that both COVID-19 and the flu led to long-term health problems, and the big aha moment was the realization that the magnitude of long-term health loss eclipsed the problems that these patients endured in the early phase of the infection. Long COVID is much more of a health problem than COVID, and long flu is much more of a health problem than the flu."

However, the overall risk and occurrence of death, hospital admissions, and loss of health in many organ systems are substantially higher among COVID-19 patients than among those who have had seasonal influenza, Al-Aly said. "The one notable exception is that the flu poses higher risks to the pulmonary system than COVID-19," he said. "This tells us the flu is truly more of a respiratory virus, like we've all thought for the past 100 years. By comparison, COVID-19 is more aggressive and indiscriminate in that it can attack the pulmonary system, but it can also strike any organ system and is more likely to cause fatal or severe conditions involving the heart, brain, kidneys and other organs."

The researchers analyzed de-identified medical records in a database maintained by the U.S. Department of Veterans Affairs, the nation's largest integrated health-care delivery system. They evaluated information involving 81,280 patients hospitalized for COVID-19 at some point from March 1, 2020, through June 30, 2022, as well as 10,985 patients hospitalized for seasonal influenza at some point from Oct. 1, 2015, through Feb. 28, 2019.

Patients represented multiple ages, races and sexes.

Regarding both viruses, patient vaccination status did not affect results. Those in the COVID-19 cohort were hospitalized during the pre-delta, delta and omicron eras.

During the overall 18-month study period, patients who had COVID-19 faced a 50% higher risk of death than those with seasonal influenza. This corresponded to about eight more deaths per 100 persons in the COVID-19 group than among those with the flu.

Although COVID-19 showed a greater risk of health loss than seasonal influenza, infection with either virus carried significant risk of disability and disease. The researchers found COVID-19 exhibited increased risk of 68% of health conditions examined across all organ systems (64 of the 94 adverse health outcomes studied), while the flu was associated with elevated risk of 6% of health conditions (six of the 94) -- mostly in the respiratory system.

Also, over 18 months, COVID-19 patients experienced an increased risk of hospital readmission as well as admission to an intensive care unit (ICU). For every 100 persons in each group, there were 20 more hospital admissions and nine more ICU admissions in COVID-19 than flu.

"Our findings highlight the continued need to reduce the risk of hospitalization for these two viruses as a way to alleviate the overall burden of health loss in populations," Al-Aly said. "For both COVID-19 and seasonal influenza, vaccinations can help prevent severe disease and reduce the risk of hospitalizations and death. Optimizing vaccination uptake must remain a priority for governments and health systems everywhere. This is especially important for vulnerable populations such as the elderly and people who are immunocompromised."

In both COVID-19 and the flu, more than half of death and disability occurred in the months after infection as opposed to the first 30 days, the latter of which is known as the acute phase.

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Unexpected chemistry reveals cosmic star factories´ secrets

Two galaxies in the early universe, which contain extremely productive star factories, have been studied by a team of scientists led by Chalmers University of Technology in Sweden. Using powerful telescopes to split the galaxies' light into individual colours, the scientists were amazed to discover light from many different molecules -- more than ever before at such distances. Studies like this could revolutionise our understanding of the lives of the most active galaxies when the universe was young, the researchers believe.

When the universe was young, galaxies were very different from today's stately spirals, which are full of gently-shining suns and colourful gas clouds. New stars were being born, at rates hundreds of times faster than in today's universe. Most of this however, was hidden behind thick layers of dust, making it a challenge for scientists to discover these star factories' secrets -- until now. By studying the most distant galaxies visible with powerful telescopes, astronomers can get glimpses of how these factories managed to create so many stars.

In a new study, published in the journal Astronomy & Astrophysics, a team of scientists led by Chalmers astronomer Chentao Yang, used the telescopes of NOEMA (NOrthern Extended Millimetre Array) in France to find out more about how these early star factories managed to create so many stars. Yang and his colleagues measured light from two luminous galaxies in the early universe -- one of them classified as a quasar, and both with high rates of star formation.

"We knew these galaxies were prodigious star factories, perhaps amongst the biggest the universe has ever seen. To be able to find out how they work, we measured their light at wavelengths around one millimetre, hoping to collect new clues," says Chentao Yang.

Dramatic chemistry in the distant galaxies excites the astronomers

The measurements proved to be successful beyond the scientists' expectations. In the light they recorded from both galaxies, they identified traces of many different kinds of molecules. From deep within these galaxies, light is emitted in many different wavelengths from the clouds of gas and dust where new stars are born.

"It's an amazing explosion of colour, in shades that the human eye can't see. But by combining our observations with our knowledge of physics and chemistry, we can understand what the colours mean, and see what differences there are between different galaxies," explains Sergio Martín, astronomer at ESO and Joint ALMA Observatory, Chile, and member of the research team.

By analysing each galaxy's spectrum -- the individual colours of their light -- the scientists were able to identify 13 molecules, several of which have never been seen before in such distant galaxies. Each molecule gives different clues about the temperature, pressure, and density in the space between the stars, and about how starlight, radiation and matter interact -- providing key new information on the physical and chemical conditions in these galaxies.

"Interpreting the signals is a challenge. We are seeing part of the electromagnetic spectrum that is hard to observe in nearby galaxies. But thanks to the expansion of the universe, the light from distant galaxies like these is shifted to longer wavelengths that we can see with radio telescopes observing in the sub-millimetre," says Chentao Yang.

More like a neon-lit city than a night under the stars

The two galaxies studied by the team are so far away that their light takes almost 13 billion years to reach us.

"Looking at these galaxies is less like a night under the stars and more like seeing a city lit with neon lights," says Susanne Aalto, Chalmers astronomer and team member.

Astronomers are used to taking pictures of our galaxy's star factories, like the Orion Nebula and the Carina Nebula, she explains.

"In these two distant galaxies, we are instead seeing star factories that are bigger, brighter, full of dust, and different in many ways. The Orion and Carina nebulae are lit up thanks to ultraviolet light from hot, newborn stars. In these two distant galaxies, ultraviolet light can't get past the layers of dust. Much of the illumination is instead thanks to cosmic rays -- high energy particles that can be created by exploding stars, or close to a supermassive black hole," says Susanne Aalto.

The galaxies in the early universe can now tell their stories

While galaxies like these two are rare, the scientists have plans to study more of them, using both NOEMA and its even bigger sister telescope, ALMA (the Atacama Large Millimetre/Submillimetre Array) in Chile. Both telescopes are sensitive to light with wavelengths of around one millimetre.

"Our results show how NOEMA, with its broadband receivers and powerful correlator computer, has opened up new opportunities for studying extreme galaxies like these in the northern sky. From the southern hemisphere, ALMA's planned wideband sensitivity upgrades will offer even more exciting prospects. The most remarkable galaxies in the early universe are finally able to tell their stories through their molecules," says Pierre Cox, astronomer at CNRS and Sorbonne Université, France.

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