Mysterious Neptune dark spot detected from Earth for the first time

Using ESO's Very Large Telescope (VLT), astronomers have observed a large dark spot in Neptune's atmosphere, with an unexpected smaller bright spot adjacent to it. This is the first time a dark spot on the planet has ever been observed with a telescope on Earth. These occasional features in the blue background of Neptune's atmosphere are a mystery to astronomers, and the new results provide further clues as to their nature and origin.

Large spots are common features in the atmospheres of giant planets, the most famous being Jupiter's Great Red Spot. On Neptune, a dark spot was first discovered by NASA's Voyager 2 in 1989, before disappearing a few years later. "Since the first discovery of a dark spot, I've always wondered what these short-lived and elusive dark features are," says Patrick Irwin, Professor at the University of Oxford in the UK and lead investigator of the study published today in Nature Astronomy.

Irwin and his team used data from ESO's VLT to rule out the possibility that dark spots are caused by a 'clearing' in the clouds. The new observations indicate instead that dark spots are likely the result of air particles darkening in a layer below the main visible haze layer, as ices and hazes mix in Neptune's atmosphere.

Coming to this conclusion was no easy feat because dark spots are not permanent features of Neptune's atmosphere and astronomers had never before been able to study them in sufficient detail. The opportunity came after the NASA/ESA Hubble Space Telescope discovered several dark spots in Neptune's atmosphere, including one in the planet's northern hemisphere first noticed in 2018. Irwin and his team immediately got to work studying it from the ground -- with an instrument that is ideally suited to these challenging observations.

Using the VLT's Multi Unit Spectroscopic Explorer (MUSE), the researchers were able to split reflected sunlight from Neptune and its spot into its component colours, or wavelengths, and obtain a 3D spectrum. This meant they could study the spot in more detail than was possible before. "I'm absolutely thrilled to have been able to not only make the first detection of a dark spot from the ground, but also record for the very first time a reflection spectrum of such a feature," says Irwin.

Since different wavelengths probe different depths in Neptune's atmosphere, having a spectrum enabled astronomers to better determine the height at which the dark spot sits in the planet's atmosphere. The spectrum also provided information on the chemical composition of the different layers of the atmosphere, which gave the team clues as to why the spot appeared dark.

The observations also offered up a surprise result. "In the process we discovered a rare deep bright cloud type that had never been identified before, even from space," says study co-author Michael Wong, a researcher at the University of California, Berkeley, USA. This rare cloud type appeared as a bright spot right beside the larger main dark spot, the VLT data showing that the new 'deep bright cloud' was at the same level in the atmosphere as the main dark spot. This means it is a completely new type of feature compared to the small 'companion' clouds of high-altitude methane ice that have been previously observed.

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2023 Global Heat Wave: July brought the hottest three weeks observed so far

The first three weeks of July 2023 have been the hottest global three-week period so far. In the summer months of 2023, twice as many people in Germany were exposed to daily temperatures of 35 degrees and higher than the average from 1980 to 1999. This is obvious from a study published recently by Karlsruhe Institute of Technology (KIT). Researchers from KIT's Center for Disaster Management and Risk Reduction Technology (CEDIM) report that the European population's exposure to heat was highest in Italy.

In the summer of the year 2023, several hot spells of variable length and intensity occurred partly simultaneously in different regions of the northern hemisphere. In their "Untersuchung der globalen Hitzewelle im Jahr 2023" (investigation of the global heat wave in 2023), researchers of the Forensic Disaster Analysis (FDA) Task Force Group of KIT's CEDIM analyzed the record temperatures reached and the population's exposure to heat.

Ocean Surface Temperatures in June 2023 Were as High as Never Before since records began

In some regions, previous all-time record temperatures were exceeded by far, in other areas new daily or monthly records were recorded. In June 2023, global mean ocean surface temperatures were as high as never before. As regards the Earth's surface, including landmass, June 2023 has been the warmest June since 1850. On a global scale, the first three weeks of July 2023 were the hottest three-week period ever. The daily record, a global surface temperature of 17.08 degrees Celsius was reached on July 6, closely followed by July 5 and 7 with 17.07 degrees Celsius each. In July 2023, extreme temperatures and new country records -- official confirmation by the World Meteorological Organization (WMO) is still pending -were reached in the Mediterranean countries, including North Africa and the Middle East. Record-breaking temperatures were also reported by the USA, Canada, and China.

"For a big temperature anomaly to develop over a longer term, a long-lasting and unusually large-scale flow pattern is required," says Dr. Andreas Schäfer from the FDA Task Force Group of CEDIM. Pressure distribution in the middle troposphere at about 5.5 kilometers altitude plays an important role, as it influences upper airflow and the associated air mass transport. "In July 2023, extraordinarily persistent high-pressure areas prevailed in the regions affected by the high temperatures. Here, descending air masses contributed significantly to warming and the local development of the heat wave," Schäfer says.

The researchers also studied the population's exposure to heat. In Germany, about seven million people were exposed to daily maximum temperatures higher than 25 degrees Celsius. These were about 40 percent more than the average number of the years 1980 to 1999. The number of persons exposed to daily temperatures of 35 degrees Celsius and higher even doubled to about 206,000. Compared to previous decades, heat exposure during the summer months was also much higher in Italy, Greece, Spain, the USA, China, and India.

Italy Reached Heat Records of More than 40 Degrees Celsius

In Europe, Italy suffered from the biggest heat by far. Here, new record heats of more than 40 degrees Celsius were measured. While only 4000 people per day had been exposed to such high temperatures from 1980 to 1999, this number increased to more than 127,000 in 2023. To counteract the negative impacts of heat exposure on human health, state institutions adopted action plans and implemented various adaptation strategies, including the installation of public wells and water dispenser systems. In Germany, such systems can mostly be found in conurbations. (or)

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Paper drinking straws may be harmful and may not be better for the environment than plastic versions

"Eco-friendly" paper drinking straws contain long-lasting and potentially toxic chemicals, a new study has concluded.

In the first analysis of its kind in Europe, and only the second in the world, Belgian researchers tested 39 brands of straws for the group of synthetic chemicals known as poly- and perfluoroalkyl substances (PFAS).

PFAS were found in the majority of the straws tested and were most common in those made from paper and bamboo, the study, published in the peer-reviewed journal Food Additives and Contaminants, found.

PFAS are used to make everyday products, from outdoor clothing to non-stick pans, resistant to water, heat and stains. They are, however, potentially harmful to people, wildlife and the environment.

They break down very slowly over time and can persist over thousands of years in the environment, a property that has led to them being known as "forever chemicals."

They have been associated with a number of health problems, including lower response to vaccines, lower birth weight, thyroid disease, increased cholesterol levels, liver damage, kidney cancer and testicular cancer.

"Straws made from plant-based materials, such as paper and bamboo, are often advertised as being more sustainable and eco-friendly than those made from plastic," says researcher Dr Thimo Groffen, an environmental scientist at the University of Antwerp, who is involved in this study.

"However, the presence of PFAS in these straws means that's not necessarily true."

A growing number of countries, including the UK and Belgium, have banned sale of single-use plastic products, including drinking straws, and plant-based versions have become popular alternatives.

A recent study found PFAS in plant-based drinking straws in the US. Dr Groffen and colleagues wanted to find out if the same was true of those on sale in Belgium.

To explore this further, the research team purchased 39 different brands of drinking straw made from five materials -- paper, bamboo, glass, stainless steel and plastic.

The straws, which were mainly obtained from shops, supermarkets and fast-food restaurants, then underwent two rounds of testing for PFAS.

The majority of the brands (27/39, 69%) contained PFAS, with 18 different PFAS detected in total.

The paper straws were most likely to contain PFAS, with the chemicals detected in 18/20 (90%) of the brands tested. PFAS were also detected in 4/5 (80%) brands of bamboo straw, 3/4 (75%) of the plastic straw brands and 2/5 (40%) brands of glass straw. They were not detected in any of the five types of steel straw tested.

The most commonly found PFAS, perfluorooctanoic acid (PFOA), has been banned globally since 2020.

Also detected were trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMS), "ultra-short chain" PFAS which are highly water soluble and so might leach out of straws into drinks.

The PFAS concentrations were low and, bearing in mind that most people tend to only use straws occasionally, pose a limited risk to human health. However, PFAS can remain in the body for many years and concentrations can build up over time.

"Small amounts of PFAS, while not harmful in themselves, can add to the chemical load already present in the body," says Dr Groffen.

It isn't known whether the PFAS were added to the straws by the manufacturers for waterproofing or whether were the result of contamination. Potential sources of contamination include the soil the plant-based materials were grown in and the water used in the manufacturing process.

However, the presence of the chemicals in almost every brand of paper straw means it is likely that it was, in some cases, being used as a water-repellent coating, say the researchers.

The study's other limitations include not looking at whether the PFAS would leach out of the straws into liquids.

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How artificial intelligence gave a paralyzed woman her voice back

Researchers at UC San Francisco and UC Berkeley have developed a brain-computer interface (BCI) that has enabled a woman with severe paralysis from a brainstem stroke to speak through a digital avatar.

It is the first time that either speech or facial expressions have been synthesized from brain signals. The system can also decode these signals into text at nearly 80 words per minute, a vast improvement over commercially available technology.

Edward Chang, MD, chair of neurological surgery at UCSF, who has worked on the technology, known as a brain computer interface, or BCI, for more than a decade, hopes this latest research breakthrough, appearing Aug. 23, 2023, in Nature, will lead to an FDA-approved system that enables speech from brain signals in the near future.

"Our goal is to restore a full, embodied way of communicating, which is really the most natural way for us to talk with others," said Chang, who is a member of the UCSF Weill Institute for Neuroscience and the Jeanne Robertson Distinguished Professor in Psychiatry. "These advancements bring us much closer to making this a real solution for patients."

Chang's team previously demonstrated it was possible to decode brain signals into text in a man who had also experienced a brainstem stroke many years earlier. The current study demonstrates something more ambitious: decoding brain signals into the richness of speech, along with the movements that animate a person's face during conversation.

Chang implanted a paper-thin rectangle of 253 electrodes onto the surface of the woman's brain over areas his team has discovered are critical for speech. The electrodes intercepted the brain signals that, if not for the stroke, would have gone to muscles in her, tongue, jaw and larynx, as well as her face. A cable, plugged into a port fixed to her head, connected the electrodes to a bank of computers.

For weeks, the participant worked with the team to train the system's artificial intelligence algorithms to recognize her unique brain signals for speech. This involved repeating different phrases from a 1,024-word conversational vocabulary over and over again, until the computer recognized the brain activity patterns associated with the sounds.

Rather than train the AI to recognize whole words, the researchers created a system that decodes words from phonemes. These are the sub-units of speech that form spoken words in the same way that letters form written words. "Hello," for example, contains four phonemes: "HH," "AH," "L" and "OW."

Using this approach, the computer only needed to learn 39 phonemes to decipher any word in English. This both enhanced the system's accuracy and made it three times faster.

"The accuracy, speed and vocabulary are crucial," said Sean Metzger, who developed the text decoder with Alex Silva, both graduate students in the joint Bioengineering Program at UC Berkeley and UCSF. "It's what gives a user the potential, in time, to communicate almost as fast as we do, and to have much more naturalistic and normal conversations."

To create the voice, the team devised an algorithm for synthesizing speech, which they personalized to sound like her voice before the injury, using a recording of her speaking at her wedding.

The team animated the avatar with the help of software that simulates and animates muscle movements of the face, developed by Speech Graphics, a company that makes AI-driven facial animation. The researchers created customized machine-learning processes that allowed the company's software to mesh with signals being sent from the woman's brain as she was trying to speak and convert them into the movements on the avatar's face, making the jaw open and close, the lips protrude and purse and the tongue go up and down, as well as the facial movements for happiness, sadness and surprise.

"We're making up for the connections between the brain and vocal tract that have been severed by the stroke," said Kaylo Littlejohn, a graduate student working with Chang and Gopala Anumanchipalli, PhD, a professor of electrical engineering and computer sciences at UC Berkeley. "When the subject first used this system to speak and move the avatar's face in tandem, I knew that this was going to be something that would have a real impact."

An important next step for the team is to create a wireless version that would not require the user to be physically connected to the BCI.

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How a cup of water can unlock the secrets of our Universe

Researchers from Queen Mary University of London have made a discovery that could change our understanding of the universe. In their study published in Science Advances, they reveal, for the first time, that there is a range in which fundamental constants can vary, allowing for the viscosity needed for life processes to occur within and between living cells. This is an important piece of the puzzle in determining where these constants come from and how they impact life as we know it.

In 2020, the same team found that the viscosity of liquids is determined by fundamental physical constants, setting a limit on how runny a liquid can be. Now this result is taken into the realm of life sciences.

Fundamental physical constants shape the fabric of the universe we live in. Physical constants are quantities with a value that is generally believed to be both universal in nature and to remain unchanged over time -- for example the mass of the electron. They govern nuclear reactions and can lead to the formation of molecular structures essential to life, but their origin is unknown. This research might bring scientists one step closer to determining where these constants come from.

"Understanding how water flows in a cup turns out to be closely related to the grand challenge to figure out fundamental constants. Life processes in and between living cells require motion and it is viscosity that sets the properties of this motion. If fundamental constants change, viscosity would change too impacting life as we know it. For example, if water was as viscous as tar life would not exist in its current form or not exist at all. This applies beyond water, so all life forms using the liquid state to function would be affected."

"Any change in fundamental constants including an increase or decrease would be equally bad news for flow and for liquid-based life. We expect the window to be quite narrow: for example, viscosity of our blood would become too thick or too thin for body functioning with only a few per cent change of some fundamental constants such as the Planck constant or electron charge." Professor of Physics Kostya Trachenko said.

Surprisingly, the fundamental constants were thought to be tuned billions of years ago to produce heavy nuclei in stars and back then life as we know it today didn't exist. There was no need for these constants to be fine-tuned at that point to also enable cellular life billions of years later, and yet these constants turn out to be bio-friendly to flow in and between living cells.

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Hot chemistry quickly transforms aromatic molecules into harmful aerosols

Joint research groups at Tampere University, University of Helsinki, Lund University and Pi-Numerics, Salzburg, have established key early steps in the conversion of aromatic molecules, a major constituent of traffic and other urban volatile emissions, into aerosol. Their findings increase understanding of the chemical processes that degrade urban air quality and influence climate change.

Many aromatic molecules are carcinogenic and have negative impacts on health. Their primary source is exhaust fumes from motor vehicles. Aromatics can form aerosol particles when they collide in the atmosphere with the hydroxyl radical, a molecule colloquially dubbed "atmospheric detergent" due to its acute propensity to react chemically. When breathed in, aerosol particles can lead to a myriad of chronic health issues and even death. These particles also affect Earth's climate by reflecting sun light and increasing the formation of clouds.

Despite their importance to the urban environment, details of the reaction processes that form aerosol from aromatics have until now remained unresolved.

The group of researchers used a combination of quantum mechanics, targeted experiments, and modeling, to establish the early steps in the reaction process of toluene, one of the most abundant aromatic molecules.

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Newly discovered 'primitive cousins of T rex' shed light on the end of the age of dinosaurs in Africa

Fossils of primitive cousins of T. rex that had short, bulldog snouts and even shorter arms have been discovered by scientists in Morocco. The two new dinosaur species belong to the Abelisauridae, a family of carnivorous dinosaurs that were counterparts to the tyrannosaurs of the Northern Hemisphere. They lived at the end of the Cretaceous period and show that dinosaurs were diverse in Africa just before their mass extinction by an asteroid 66 million years ago.

Two new species of dinosaur have been found from the end of the Cretaceous in Morocco, just outside of Casablanca. One species, found near the town of Sidi Daoui, is represented by a foot bone from a predator about two and a half metres (eight feet) long. The other, from nearby Sidi Chennane, is the shin bone of a carnivore that grew to around five metres (15 feet) in length.

Both were part of a family of primitive carnivorous dinosaurs known as abelisaurs, and lived alongside the much larger abelisaur Chenanisaurus barbaricus, showing that Morocco was home to diverse dinosaur species just before a giant asteroid struck at the end of the Cretaceous, ending the age of dinosaurs.

Dr Nick Longrich, from the Milner Centre for Evolution at the University of Bath, led the study. He said: "What's surprising here is that these are marine beds.

"It's a shallow, tropical sea full of plesiosaurs, mosasaurs, and sharks. It's not exactly a place you'd expect to find a lot of dinosaurs. But we're finding them."

Even though dinosaurs account for a small proportion of the fossils, the region is so rich in fossils, it has produced the best picture of African dinosaurs from the end of the age of dinosaurs.

Rather than finding the same few species, palaeontologists often recover fossils from new species, suggesting the beds host an extremely diverse dinosaur fauna.

So far, the small number of dinosaur fossils that have been recovered represent five different species -- a small duckbill dinosaur named Ajnabia, a long-necked titanosaur, the giant abelisaur Chenanisaurus, and now the two new abelisaurs.

Dr Longrich said: "We have other fossils as well, but they're currently under study. So we can't say much about them at the moment, except that this was an amazingly diverse dinosaur fauna."

The last dinosaurs vanished around 66 million years ago, along with as much as 90% of all species on earth, including mosasaurs, plesiosaurs, pterosaurs and ammonites. The pattern of the end-Cretaceous extinction and its causes have been debated for over two hundred years.

A giant asteroid impact in the Yucatan peninsula has been linked to their demise, although it's been argued that dinosaurs were already in decline. The Moroccan dinosaurs suggest that they thrived in North Africa up to the very end.

"The end of the Cretaceous in western North America definitely seems to become less diverse at the end," said Longrich. "But that's just one small part of the world. It's not clear that you can generalise from the dinosaurs of Wyoming and Montana to the whole world.

"It also grew colder near the end, so it might not be surprising if dinosaurs at higher latitudes became less diverse. But we don't know much about dinosaurs from lower latitudes."

In Morocco at least, they seem to have remained diverse and successful up until the end.

"When T. rex reigned as a megapredator in North America, abelisaurs sat at the top of the food chains in North Africa," said Nour-Eddine Jalil, a professor at the Natural History Museum and a researcher at Universite Cadi Ayyad in Morocco, who was a co-author on the paper.

"The dinosaur remains, despite their rarity, give the same messages as the more abundant marine reptile remains.

"They tell us that, just before the Cretaceous-Paleogene crisis, biodiversity was not declining but on the contrary, was diverse."

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Researchers fully sequence the Y chromosome for the first time

What was once the final frontier of the human genome -- the Y chromosome -- has just been mapped out in its entirety.

Led by the National Human Genome Research Institute (NHGRI), a team of researchers at the National Institute of Standards and Technology (NIST) and many other organizations used advanced sequencing technologies to read out the full DNA sequence of the Y chromosome -- a region of the genome that typically drives male reproductive development. The results of a study published in Nature demonstrate that this advance improves DNA sequencing accuracy for the chromosome, which could help identify certain genetic disorders and potentially uncover the genetic roots of others.

DNA sequencing isn't as simple as reading genetic material from a genome's beginning to its end. DNA gets chopped up when it is extracted from cells, plus even the best sequencing equipment can only handle relatively small bits of DNA at a time. So, researchers and clinicians rely on special software to piece together fragments of sequenced code in the correct order like a puzzle.

A reference genome is a separate, already pieced-together genome that serves as a guide, similar to the pictures on the front of puzzle boxes. And because 99.9% of our species' genetic code is shared, any human genome would closely match a reference.

Last year, a team from the Telomere-to-Telomere (T2T) consortium, which is made up of experts from dozens of organizations such as NIST, generated the most complete reference genome at the time by using new sequencing technologies to crack previously indecipherable regions of the genome. But cells used in that work did not contain the most puzzling of all, the Y chromosome.

"Chromosomes all contain sections of very repetitive DNA, but well over half of the Y chromosome is like that," said study co-author Justin Zook, who leads NIST's Genome in a Bottle (GIAB) consortium. "If you use the puzzle analogy, a lot of the Y chromosome looks like the backgrounds often do, where all the pieces look really similar."

With this new endeavor, T2T was not starting at zero as the GIAB had already gotten the ball rolling.

The GIAB's mission is to produce test materials, or benchmarks, that can be used to evaluate sequencing technologies or methods. The materials themselves are highly accurate readouts of specific genes that can act as an answer key for checking the results of a particular sequencing method.

NIST has rigorously analyzed several individual human genomes to create their benchmarks. While GIAB has not yet produced a benchmark for the Y chromosome specifically, the consortium has studied one genome extensively, accumulating the largest collection of Y chromosome data prior to the new study.

That data served as a jumping-off point for the new study's authors, who focused their analysis on the best understood GIAB Y chromosome. They examined the sample with a combination of cutting-edge technologies -- namely high fidelity and nanopore sequencing -- that make the DNA fragment puzzle pieces larger and thus easier to assemble.

A machine-learning analysis tool and gamut of other advanced programs helped the team identify and assemble the pieces of the chromosome. More than 62 million letters of genetic code later, the authors had spelled out the GIAB Y chromosome front to back.

The researchers pitted their complete Y chromosome sequence, named T2T-Y, against the most widely used reference genome's Y chromosome parts, which are riddled with stretches of absent code. Using them both as guides for sequencing a diverse group of over 1,200 separate genomes, they found that T2T-Y drastically improved the outcomes.

T2T-Y, in combination with the group's previous reference genome, T2T-CHM13, represents the world's first complete genome for the half of the population with a Y chromosome.

The newest addition could be useful in identifying and diagnosing the few known conditions related to genes in the Y chromosome. But what's more is the new reference's potential to shed light on new genes and their function.

"There are certainly aspects of fertility and some genetic disorders that are connected to genes in the Y chromosome," Zook said. "But because it's been so hard to analyze up to this point, we may not even know yet just how important the Y chromosome is."

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This fish doesn't just see with its eyes -- it also sees with its skin

A few years ago while on a fishing trip in the Florida Keys, biologist Lori Schweikert came face to face with an unusual quick-change act. She reeled in a pointy-snouted reef fish called a hogfish and threw it onboard. But later when she went to put it in a cooler she noticed something odd: its skin had taken on the same color and pattern as the deck of the boat.

A common fish in the western Atlantic Ocean from North Carolina to Brazil, the hogfish is known for its color-changing skin. The species can morph from white to mottled to reddish-brown in a matter of milliseconds to blend in with corals, sand or rocks.

Still, Schweikert was surprised because this hogfish had continued its camouflage even though it was no longer alive. Which got her wondering: can hogfish detect light using only their skin, independently of their eyes and brain?

"That opened up this whole field for me," Schweikert said.

In the years that followed, Schweikert started researching the physiology of "skin vision" as a postdoctoral fellow at Duke University and Florida International University.

In 2018, Schweikert and Duke biologist Sönke Johnsen published a study showing that hogfish carry a gene for a light-sensitive protein called opsin that is activated in their skin, and that this gene is different from the opsin genes found in their eyes.

Other color-changing animals from octopuses to geckos have been found to make light-sensing opsins in their skin, too. But exactly how they use them to help change color is unclear.

"When we found it in hogfish, I looked at Sönke and said: Why have a light detector in the skin?" said Schweikert, now an assistant professor at the University of North Carolina Wilmington.

One hypothesis is that light-sensing skin helps animals take in their surroundings. But new findings suggest another possibility -- "that they could be using it to view themselves," Schweikert said.

In a study appearing Aug. 22 in the journal Nature Communications, Schweikert, Johnsen and colleagues teamed up to take a closer look at hogfish skin.

The researchers took pieces of skin from different parts of the fish's body and took pictures of them under a microscope.

Up close, a hogfish's skin looks like a pointillist painting. Each dot of color is a specialized cell called a chromatophore containing granules of pigment that can be red, yellow or black.

It's the movement of these pigment granules that changes the skin color. When the granules spread out across the cell, the color appears darker. When they cluster together into a tiny spot that's hard to see, the cell becomes more transparent.

Next, the researchers used a technique called immunolabeling to locate the opsin proteins within the skin. They found that in the hogfish, opsins aren't produced in the color-changing chromatophore cells. Instead, the opsins reside in other cells directly beneath them.

Images taken with a transmission electron microscope revealed a previously unknown cell type, just below the chromatophores, packed with opsin protein.

This means that light striking the skin must pass through the pigment-filled chromatophores first before it reaches the light-sensitive layer, Schweikert said.

The researchers estimate that the opsin molecules in hogfish skin are most sensitive to blue light. This happens to be the wavelength of light that the pigment granules in the fish's chromatophores absorb best.

The findings suggest that fish's light-sensitive opsins act somewhat like internal Polaroid film, capturing changes in the light that is able to filter through the pigment-filled cells above as the pigment granules bunch up or fan out.

"The animals can literally take a photo of their own skin from the inside," Johnsen said. "In a way they can tell the animal what it's skin looks like, since it can't really bend over to look."

"Just to be clear, we're not arguing that hogfish skin functions like an eye," Schweikert added. Eyes do more than merely detect light -- they form images. "We don't have any evidence to suggest that's what's happening in their skin," Schweikert said.

Rather, it's a sensory feedback mechanism that lets the hogfish monitor its own skin as it changes color, and fine-tune it to fit what it sees with its eyes.

"They appear to be watching their own color change," Schweikert said.

The researchers say the work is important because it could pave the way to new sensory feedback techniques for devices such as robotic limbs and self-driving cars that must fine-tune their performance without relying solely on eyesight or camera feeds.

"Sensory feedback is one of the tricks that technology is still trying to figure out," Johnsen said. "This study is a nice dissection of a new sensory feedback system."

"If you didn't have a mirror, and you couldn't bend your neck, how would you know if you're dressed appropriately?" Schweikert said. "For us it may not matter," she added. But for creatures that use their color-changing abilities to hide from predators, warn rivals or woo mates, "it could be life or death."

Read more at Science Daily

New platform could boost development of carbon-capturing batteries

Efficient and cheap batteries that can also capture harmful emissions could be right around the corner, thanks to a new system that speeds up the development of catalysts for lithium-CO2 (Li-CO2) batteries.

The technology has been developed by the University of Surrey, Imperial College London, and Peking University to address the slow and inefficient methods currently used to produce catalysts for Li-CO2 batteries.

In the study, researchers used their tool to test and screen materials like platinum, gold, silver, copper, iron and nickel to easily investigate whether they would be suitable candidates for developing high-performing Li-CO2 batteries.

Dr Kai Yang, corresponding author of this work, project co-leader and Lecturer from the Advanced Technology Institute at the University of Surrey, explained:

"We have created a cutting-edge lab-on-a-chip electrochemical testing platform that can do multiple things at the same time. It helps evaluate electrocatalysts, optimise operation conditions, and study CO2 conversion in high-performance lithium-CO2 batteries. This new method is more cost-effective, efficient, and controllable than traditional ways of making these materials."

Li-CO2 batteries are a promising new type of battery that work by combining lithium and carbon dioxide; they not only store energy effectively but also offer a way to capture CO2, potentially making a dual-contribution to the fight against climate change.

Dr Yunlong Zhao, the lead corresponding author of this study and a Senior Lecturer at Imperial College London, the National Physical Laboratory, and visiting academic from the University of Surrey, said:

"It is crucial that we develop new negative emissions technologies. Our lab-on-a-chip platform will play a crucial role in advancing this goal. It will not only enhance our understanding of novel batteries, but it can also be applied to other systems like metal-air batteries, fuel cells, and photoelectrochemical cells.

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Researchers extract ancient DNA from a 2,900-year-old clay brick, revealing a time capsule of plant life

Currently housed at the National Museum of Denmark, the clay brick originates from the palace of Neo-Assyrian king Ashurnasirpal II, in the ancient city of Kalhu. Known today as the North-West palace in Nimrud (modern-day northern Iraq), its construction began around 879 BCE. The brick has a cuneiform inscription (written in the now extinct Semitic language Akkadian) stating that it is 'The property of the palace of Ashurnasirpal, king of Assyria.' This makes it possible to date the brick precisely to within a decade (879 BCE to 869 BCE).

During a digitalization project at the Museum in 2020, the group of researchers were able to obtain samples from the inner core of the brick -- meaning that there was a low risk of DNA contamination since the brick was created. The team extracted DNA from the samples by adapting a protocol previously used for other porous materials, such as bone.

After the extracted DNA had been sequenced, the researchers identified 34 distinct taxonomic groups of plants. The plant families with the most abundant sequences were Brassicaceae (cabbage) and Ericaceae (heather). Other represented families were Betulaceae (birch), Lauraceae (laurels), Selineae (umbellifiers) and Triticeae (cultivated grasses).

With the interdisciplinary team comprising assyriologists, archaeologists, biologists, and geneticists, they were able to compare their findings with modern-day botanical records from Iraq as well as ancient Assyrian plant descriptions.

The brick would have been made primarily of mud collected near the local Tigris river, mixed with material such as chaff or straw, or animal dung. It would have been shaped in a mould before being inscribed with cuneiform script, then left in the sun to dry. The fact that the brick was never burned, but left to dry naturally, would have helped to preserve the genetic material trapped within the clay.

Dr Sophie Lund Rasmussen (Wildlife Conservation Research Unit, Department of Biology, University of Oxford), joint first author of the paper, said: 'We were absolutely thrilled to discover that ancient DNA, effectively protected from contamination inside a mass of clay, can successfully be extracted from a 2,900-year-old clay brick. This research project is a perfect example of the importance of interdisciplinary collaboration in science, as the diverse expertise included in this study provided a holistic approach to the investigation of this material and the results it yielded.'

In addition to the fascinating insight this individual brick revealed, the research serves as a proof of concept and method which could be applied to many other archaeological sources of clay from different places and time periods around the world, to identify past flora and fauna. Clay materials are nearly always present in any archaeological site around the world, and their context means they can often be dated with high precision.

This study only described the plant DNA extracted, as these were the most prevalent and best-preserved specimens. However, depending on the sample, all taxa could potentially be identified, including vertebrates and invertebrates. The ability to provide accurate descriptions of ancient biodiversity would be a valuable tool to better understand and quantify present day biodiversity loss, and to gain a deeper understanding of ancient and lost civilisations.

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Formerly depressed patients continue to focus on negative

People who have recovered from a major depressive episode, when compared with individuals who have never experienced one, tend to spend more time processing negative information and less time processing positive information, putting them at risk for a relapse, according to research published by the American Psychological Association.

"Our findings suggest that people who have a history of depression spend more time processing negative information, such as sad faces, than positive information, such as happy faces, and that this difference is greater compared to healthy people with no history," said lead author Alainna Wen, PhD, a postdoctoral scholar at the Anxiety and Depression Research Center at the University of California, Los Angeles. "Because more negative thinking and mood and less positive thinking and mood are characteristic of depression, this could mean that these individuals are at a greater risk for having another depressive episode."

The research was published in the Journal of Psychopathology and Clinical Science.

Major depression is one of the most common mental disorders in the United States. In 2020, approximately 21 million U.S. adults reported at least one incidence of major depression (8.4% of the U.S. population), according to the National Institute of Mental Health. Defined as a period of at least two weeks of a depressed mood or loss of interest or pleasure in daily activities, major depression can interfere with or limit a person's ability to carry out major life activities.

Despite well-established treatments for depression, relapse rates for major depressive disorder remain high, according to Wen. More than 50% of individuals with a first-time major depressive episode will experience subsequent episodes, often relapsing within two years of recovery. Thus, more insight is needed into the risk factors involved in major depressive disorder to improve treatment and prevent relapse.

For this paper, researchers conducted a meta-analysis of 44 studies involving 2081 participants with a history of major depressive disorder and 2285 healthy controls. All studies examined participants' response times to negative, positive or neutral stimuli. In some cases, participants were shown either a happy, sad or neutral human face and asked to push a different button for each. In others, participants reacted to positive, negative or neutral words.

Healthy participants as a group responded more quickly to emotional and non-emotional stimuli than participants with a history of depression, regardless of whether those stimuli were positive, neutral or negative. But participants who previously had major depressive disorder spent more time processing negative emotional stimuli over positive stimuli compared with controls. While healthy controls showed a significant difference in how much time they spent processing positive vs. negative emotional stimuli compared with those in remission from major depression, that distinction did not appear when comparing time spent processing negative vs. neutral or positive vs. neutral stimuli.

Overall, the findings suggest that individuals with recurrent major depressive disorder not only are less able to control the information they process than healthy individuals, they also display a greater bias for focusing on negative over positive or neutral information, according to Wen.

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Want to know how light works? Try asking a mechanic

Since the 17th century, when Isaac Newton and Christiaan Huygens first debated the nature of light, scientists have been puzzling over whether light is best viewed as a wave or a particle -- or perhaps, at the quantum level, even both at once. Now, researchers at Stevens Institute of Technology have revealed a new connection between the two perspectives, using a 350-year-old mechanical theorem -- ordinarily used to describe the movement of large, physical objects like pendulums and planets -- to explain some of the most complex behaviors of light waves.

The work, led by Xiaofeng Qian, assistant professor of physics at Stevens and reported in the August 17 online issueof Physical Review Research, also proves for the first time that a light wave's degree of non-quantum entanglement exists in a direct and complementary relationship with its degree of polarization. As one rises, the other falls, enabling the level of entanglement to be inferred directly from the level of polarization, and vice versa. This means that hard-to-measure optical properties such as amplitudes, phases and correlations -- perhaps even these of quantum wave systems -- can be deduced from something a lot easier to measure: light intensity.

"We've known for over a century that light sometimes behaves like a wave, and sometimes like a particle, but reconciling those two frameworks has proven extremely difficult," said Qian "Our work doesn't solve that problem -- but it does show that there are profound connections between wave and particle concepts not just at the quantum level, but at the level of classical light-waves and point-mass systems."

Qian's team used a mechanical theorem, originally developed by Huygens in a 1673 book on pendulums, that explains how the energy required to rotate an object varies depending on the object's mass and the axis around which it turns. "This is a well-established mechanical theorem that explains the workings of physical systems like clocks or prosthetic limbs," Qian explained. "But we were able to show that it can offer new insights into how light works, too."

This 350-year-old theorem describes relationships between masses and their rotational momentum, so how could it be applied to light where there is no mass to measure? Qian's team interpreted the intensity of a light as the equivalent of a physical object's mass, then mapped those measurements onto a coordinate system that could be interpreted using Huygens' mechanical theorem. "Essentially, we found a way to translate an optical system so we could visualize it as a mechanical system, then describe it using well-established physical equations," explained Qian.

Once the team visualized a light wave as part of a mechanical system, new connections between the wave's properties immediately became apparent -- including the fact that entanglement and polarization stood in a clear relationship with one another.

"This was something that hadn't been shown before, but that becomes very clear once you map light's properties onto a mechanical system," said Qian. "What was once abstract becomes concrete: using mechanical equations, you can literally measure the distance between 'center of mass' and other mechanical points to show how different properties of light relate to one another."

Clarifying these relationships could have important practical implications, allowing subtle and hard-to-measure properties of optical systems -- or even quantum systems -- to be deduced from simpler and more robust measurements of light intensity, Qian explained. More speculatively, the team's findings suggest the possibility of using mechanical systems to simulate and better-understand the strange and complex behaviors of quantum wave systems.

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Thinning ice sheets may drive sharp rise in subglacial waters

Two Georgia Tech researchers, Alex Robel and Shi Joyce Sim, have collaborated on a new model for how water moves under glaciers. The new theory shows that up to twice the amount of subglacial water that was originally predicted might be draining into the ocean -- potentially increasing glacial melt, sea level rise, and biological disturbances.

The paper, published in Science Advances, "Contemporary Ice Sheet Thinning Drives Subglacial Groundwater Exfiltration with Potential Feedbacks on Glacier Flow," is co-authored by Colin Meyer (Dartmouth), Matthew Siegfried (Colorado School of Mines), and Chloe Gustafson (USGS).

While there are pre-existing methods to understand subglacial flow, these techniques involve time-consuming computations. In contrast, Robel and Sim developed a simple equation, which can predict how fast exfiltration, the discharge of groundwater from aquifers under ice sheets, using satellite measurements of Antarctica from the last two decades.

"In mathematical parlance, you would say we have a closed form solution," explains Robel, an assistant professor in the School of Earth and Atmospheric Sciences. "Previously, people would run a hydromechanical model, which would have to be applied at every point under Antarctica, and then run forward over a long time period." Since the researchers' new theory is a mathematically simple equation, rather than a model, "the entirety of our prediction can be done in a fraction of a second on a laptop," Robel says.

Robel adds that while there is precedence for developing these kinds of theories for similar kinds of models, this theory is specific in that it is for the particular boundary conditions and other conditions that exist underneath ice sheets. "This is, to our knowledge, the first mathematically simple theory which describes the exfiltration and infiltration underneath ice sheets."

"It's really nice whenever you can get a very simple model to describe a process -- and then be able to predict what might happen, especially using the rich data that we have today. It's incredible" adds Sim, a research scientist in the School of Earth and Atmospheric Sciences. "Seeing the results was pretty surprising."

One of the main arguments in the paper underscores the potentially large source of subglacial water -- possibly up to double the amount previously thought -- that could be affecting how quickly glacial ice flows and how quickly the ice melts at its base. Robel and Sim hope that the predictions made possible by this theory can be incorporated into ice sheet models that scientists use to predict future ice sheet change and sea level rise.

A dangerous feedback cycle

Aquifers are underground areas of porous rock or sediment rich in groundwater. "If you take weight off aquifers like there are under large parts of Antarctica, water will start flowing out of the sediment," Robel explains, referencing a diagram Sim created. While this process, known as exfiltration, has been studied previously, focus has been on the long time scales of interglacial cycles, which cover tens of thousands of years.

There has been less work on modern ice sheets, especially on how quickly exfiltration might be occurring under the thinning parts of the current-day Antarctic ice sheet. However, using recent satellite data and their new theory, the team has been able to predict what exfiltration might look like under those modern ice sheets.

"There's a wide range of possible predictions," Robel explains. "But within that range of predictions there is the very real possibility that groundwater may be flowing out of the aquifer at a speed that would make it a majority, or close to a majority of the water that is underneath the ice sheet."

If those parameters are correct, that would mean there's twice as much water coming into the subglacial interface than previous estimates assumed.

Ice sheets act like a blanket, sitting over the warm earth and trapping heat on the bottom, away from Antarctica's cold atmosphere -- and this means that the warmest place in the Antarctic ice sheet is at the bottom of a sheet, not on the surface. As an ice sheet thins, the warmer underground water can exfiltrate more readily, and this heat gradient can accelerate the melting that an ice sheet experiences.

"When the atmosphere warms up, it takes tens of thousands of years for that signal to diffuse through an ice sheet of the size of the thickness of the Antarctic ice sheet," Robel explains. "But this process of exfiltration is a response to the already-ongoing thinning of the ice sheet, and it's an immediate response right now."

Broad implications

Beyond sea level rise, this additional exfiltration and melt has other implications. Some of the places of richest marine productivity in the world occur off the coast of Antarctica, and being able to better predict exfiltration and melt could help marine biologists better understand where marine productivity is occurring, and how it might change in the future.

Robel also hopes this work will open the doorway to more collaborations with groundwater hydrologists who may be able to apply their expertise to ice sheet dynamics, while Sim underscores the need for more fieldwork.

"Getting the experimentalists and observationalists interested in trying to help us better constrain some of the properties of these water-laden sediments -- that would be very helpful," Sim says. "That's our largest unknown at this point, and it heavily influences the results."

"It's really interesting how there's a potential to draw heat from deeper in the system," she adds. "There's quite a lot of water that could be drawing more heat out, and I think that there's a heat budget there that could be interesting to look at."

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Did sabertooth tigers purr or roar?

When a sabertooth tiger called out, what noise did it make -- a mighty roar or a throaty purr? A new study from North Carolina State University examined the data behind the arguments for each vocalization and found that the answer was more nuanced than they thought -- and that it could depend on the shape of a few small bones.

Modern cats belong to one of two groups: either the pantherine "big cats," including the roaring lions, tigers and jaguars; or Felinae "little cats," which include purring cats like lynxes, cougars, ocelots and domestic cats.

"Evolutionarily speaking, sabertooths split off the cat family tree before these other modern groups did," says Adam Hartstone-Rose, professor of biological sciences at NC State and corresponding author of the research. "This means that lions are more closely related to housecats than either are to sabertooths.

"That's important because the debate over the kind of vocalization a sabertooth tiger would have made relies upon analyzing the anatomy of a handful of tiny bones located in the throat," Hartstone-Rose says. "And the size, shape and number of those bones differ between modern roaring and purring cats."

Although vocalization is driven by the larynx and soft tissue in the throat, not bones, anatomists noticed that the bones responsible for anchoring those tissues in place -- the hyoid bones -- differed in size and number between roaring and purring cats.

"While humans have only one hyoid bone, purring cats have nine bones linked together in a chain and roaring cats have seven," says Ashley Deutsch, a Ph.D. student at NC State and lead author of the research. "The missing bones are located toward the top of the hyoid structure near where it connects to the skull."

"Because sabertooth tigers only have seven bones in their hyoid structure, the argument has been that of course they roared," Hartstone-Rose says. "But when we looked at the anatomy of modern cats, we realized that there isn't really hard evidence to support this idea, since the bones themselves aren't responsible for the vocalization. That relationship between the number of bones and the sound produced hasn't ever really been proven."

The researchers looked at the hyoid structures of four species of roaring cats: lions, tigers, leopards and jaguars; and five species of purring cats: cougars, cheetahs, caracals, servals and ocelots. They compared these to 105 hyoid bones from the iconic sabertooth tiger Smilodon fatalis.

"You can argue that since the sabertooths only have seven bones they roared, but that's not the whole story," Hartstone-Rose says. "The anatomy is weird. They're missing extra bones that purring cats have, but the shape and size of the hyoid bones are distinct. Some of them are shaped more like those of purring cats, but much bigger."

According to the researchers, if the missing bones (called epihyoid bones) were key to different vocalizations, the bones most closely connected to them should look different between the two groups. However, those bones looked very similar in shape whether they came from purring or roaring cats.

In fact, the researchers saw more shape variation in the bones closer to the vocal apparatus; i.e., the thyrohyoid and basihyoid bones. The uniformity of the upper bones between the two groups suggests that if the hyoid structure plays a role in vocalization, the lower bones are more important than the upper ones. So having these key hyoid bones shaped like those of purring cats could indicate that they purred rather than roared.

"We found that despite what history has told us about the number of bones in the hyoid structure, no one has validated the significance of that difference," Hartstone-Rose says. "If vocalization is about the number of bones in the hyoid structure, then sabertooths roared. If it's about shape, they might have purred. Due to the fact that the sabertooths have things in common with both groups, there could even be a completely different vocalization."

"It is perhaps most likely that the size of the hyoids plays a role in the pitch of vocalization," says Deutsch. "Although Smilodon wasn't quite as big as the largest modern cats, its hyoid bones are substantially larger than those of any of their living relatives, so potentially they had even deeper vocalizations than the largest tigers and lions."

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Bronze Age family systems deciphered: Mainz palaeogeneticists analyse a 3,800-year-old extended family

The diversity of family systems in prehistoric societies has always fascinated scientists. A groundbreaking study by Mainz anthropologists and an international team of archaeologists now provides new insights into the origins and genetic structure of prehistoric family communities.

Researchers Jens Blöcher and Joachim Burger from Johannes Gutenberg University Mainz (JGU) have analysed the genomes of skeletons from an extended family from a Bronze Age necropolis in the Russian steppe. The 3,800-year-old "Nepluyevsky" burial mound was excavated several years ago and is located on the geographical border between Europe and Asia. Using statistical genomics, the family and marriage relationships of this society have now been deciphered. The study was carried out in cooperation with archaeologists from Ekaterinburg and Frankfurt a. M. and was partly financially supported by the German Research Foundation (DFG) and the Russian Science Foundation (RSCF).

The kurgan (burial mound) investigated was the grave of six brothers, their wives, children and grandchildren. The presumably oldest brother had eight children with two wives, one of whom came from the Asian steppe regions in the east. The other brothers showed no signs of polygamy and probably lived monogamously with far fewer children.

Fascinating snapshot of a prehistoric family

"The burial site provides a fascinating snapshot of a prehistoric family," explains Jens Blöcher, lead author of the study. "It is remarkable that the first-born brother apparently had a higher status and thus greater chances of reproduction. The right of the male firstborn seems familiar to us, it is known from the Old Testament, for example, but also from the aristocracy in historical Europe."

The genomic data reveal even more. Most women buried in the kurgan were immigrants. The sisters of the buried brothers, in turn, found new homes elsewhere. Joachim Burger, senior author of the study, explains: "Female marriage mobility is a common pattern that makes sense from an economic and evolutionary perspective. While one sex stays local and ensures the continuity of the family line and property, the other marries in from the outside to prevent inbreeding."

The genomic diversity of the prehistoric women was higher than that of the men

Accordingly, the Mainz population geneticists found that the genomic diversity of the prehistoric women was higher than that of the men. The women who married into the family thus came from a larger area and were not related to each other. In their new homeland, they followed their husbands into the grave. From this the authors conclude that in Nepluyevsky there was both "patrilineality", i.e. the transmission of local traditions through the male line, and "patrilocality", i.e. the place of residence of a family is the place of residence of the men.

"Archaeology shows that 3,800 years ago, the population in the southern Trans-Ural knew cattle breeding and metalworking and subsisted mainly on dairy and meat products," comments Svetlana Sharapova, archaeologist from Ekaterinburg and head of the excavation, adding, "the state of health of the family buried here must have been very poor. The average life expectancy of the women was 28 years, that of the men 36 years."

In the last generation, the use of the kurgan suddenly stopped and almost only infants and small children were found. Sharapova adds, "it is possible that the inhabitants were decimated by disease or that the remaining population went elsewhere in search of a better life."

Multiple partners and many children for the putative firstborn son

"There is a global connection between different family systems and certain forms of life-style and economy," says Blöcher. "Nevertheless, human societies are characterised by a high degree of flexibility." He adds, "in Nepluyevsky, we find evidence of a pattern of inequality typical of pastoralists: multiple partners and many children for the putative firstborn son and no or monogamous relationships for most others."

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Rewriting the past and future of the universe

New research has improved the accuracy of the parameters governing the expansion of the Universe. More accurate parameters will help astronomers determine how the Universe grew to its current state, and how it will evolve in the future.

It is well established that the Universe is expanding. But with no landmarks in space, it is difficult to accurately measure how fast it is expanding. So, astronomers search for reliable landmarks. The same way a candle looks fainter as it gets farther away, even though the candle itself hasn't changed, distant objects in the Universe look fainter. If we know the intrinsic (initial) brightness of an object, we can calculate its distance based on its observed brightness. Objects of known brightness in the Universe that allow us to calculate the distance are called "standard candles."

An international team led by Maria Giovanna Dainotti, Assistant Professor at the National Astronomical Observatory of Japan (NAOJ), and Giada Bargiacchi, PhD student at the Scuola Superiore Meridionale in Naples, with the aid of the supercomputing facilities at NAOJ run by Kazunari Iwasaki, Assistant Professor at NAOJ and member of the Center for Computational Astrophysics, ushered in a new research field by leveraging the use of a variety of new statistical methods to analyze data for various standard candles such as Supernovae, Quasars (powerful black holes consuming matter in the distant Universe), and Gamma Ray Bursts (sudden flashes of powerful radiation). Different standard candles are useful in different distant ranges, so combining multiple standard candles allowed the team to map larger areas of the Universe.

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World's deepest coral calcification rates measured off Hawaiian Islands

In the waters off the Hawaiian Islands, rates of calcification were measured in the deepest coral colonies and reported recently in a study led by a University of Hawai'i (UH) at Manoa oceanographer.

Reef building corals require light for photosynthesis to build the reef structure through calcification, but available light declines quickly with increasing water depth. Below about 200 feet, calcification rates for light-dependent corals had previously not been measured.

In the new study published in Coral Reefs, Samuel Kahng, lead author and graduate affiliate faculty of oceanography in the UH Manoa School of Ocean and Earth Science and Technology (SOEST), reported the first calcification rates from corals (Leptoseris spp.) in Hawai'i at depths of 230-360 feet.

"In addition to being from the deepest coral analyzed, these are by far the lowest calcification rates ever measured for healthy, light-dependent corals in their natural habitat," said Kahng. "These rates are 20-40 times slower than observed in shallow water corals."

Leptoseris spp. dominate the coral community in deep, low-light zones throughout the Indo-Pacific region. This species of coral exhibits a strategic approach to expanding the surface area with which it captures downwelling light -- they form very thin horizontal plate-like skeletons to maximize the area that can be built by their very low calcification rates. Kahng and colleagues published a previous study revealing that the lateral growth rates of these plate-like skeletons are unexpectedly high, given the low light availability.

"The corals' ability to quickly grow horizontal surface area is impressive, especially given the low calcification rates," said Kahng. "What this points to is the incredibly efficient use of calcification."

Because Hawai'i has such clear water, coral reef ecosystems extend offshore to extreme depths, with specialized light-dependent coral communities as deep as 500 feet.

"Hawai'i has much more vertical habitat compared to other coral reef ecosystems around the world," said Kahng. "These deep 'mesophotic' coral ecosystems can cover more habitat area than shallow water coral reefs. However, the general public rarely see them, so they present unique ecosystem management and conservation challenges."

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Cracking the code that relates brain and behavior in a simple animal

To understand the full relationship between brain activity and behavior, scientists have needed a way to map this relationship for all of the neurons across a whole brain -- a so far insurmountable challenge. But after inventing new technologies and methods for the purpose, a team of scientists in The Picower Institute for Learning and Memory at MIT has produced a rigorous accounting of the neurons in the tractably tiny brain of a humble C. elegans worm, mapping out how its brain cells encode almost all of its essential behaviors, such as movement and feeding.

In the journal Cell, the team presents new brain-wide recordings and a mathematical model that accurately predicts the versatile ways that neurons represent the worm's behaviors. Applying that model specifically to each cell, the team produced an atlas of how most cells, and the circuits they take part in, encode the animal's actions. The atlas therefore reveals the underlying "logic" of how the worm's brain produces a sophisticated and flexible repertoire of behaviors, even as its environmental circumstances change.

"This study provides a global map of how the animal's nervous system is organized to control behavior," said senior author Steven Flavell, Associate Professor in MIT's Department of Brain and Cognitive Sciences. "It shows how the many defined nodes that make up the animal's nervous system encode precise behavioral features, and how this depends on factors like the animal's recent experience and current state."

Graduate students Jungsoo Kim and Adam Atanas, who each earned their PhDs this spring for the research, are the study's co-lead authors. They've also made all their data, and the findings of their model and atlas, freely available to fellow researchers at a website called the WormWideWeb.

Microscopes to models

To make the measurements needed to develop their model, Flavell's lab invented a new microscope and software system that automatically tracks almost all behaviors of the worm (movement, feeding, sleeping, egg-laying, etc.) and the activity of every neuron in its head (cells are engineered to flash when calcium ions build up). Reliably distinguishing and tracking separate neurons as the worm wriggles around and bends required writing custom software, utilizing the latest tools from machine learning. It proved to be 99.7 percent accurate in sampling individual neuron's activities with greatly improved signal-to-noise compared to previous systems, the scientists report.

The team used the system to record simultaneous behavior and neural data from more than 60 worms as they roved about their dishes, doing whatever they wanted.

Data analysis revealed three novel observations about neural activity in the worm: Neurons track behavior not only of the present moment but also the recent past; they tune their encoding of behaviors, such as motion, based on a surprising variety of factors; and many neurons simultaneously encode multiple behaviors.

For example, while the behavior of wriggling around one's little laboratory dish might seem like a very simple act, neurons represented factors such as speed, steering, and whether the worm is eating or not. In some cases they represented the animal's motion spanning back in time by about a minute. By encoding recent, rather than just current motion, these neurons could help the worm compute how its past actions influenced its current outcome. Many neurons also combined behavioral information to execute more complex maneuvers. Much like a human driver must remember to steer the car in the opposite way when going in reverse versus going forward, certain neurons in the worm's brain integrated the animal's direction of motion and steering direction.

By carefully analyzing these kinds of patterns of how neural activity correlated with behaviors the scientists developed the C. elegans Probabilistic Neural Encoding Model. The model, encapsulated in a single equation, accounts for how each neuron represents various factors to accurately predict whether and how the neural activity reflects behavior. Nearly 60 percent of the neurons in the worm's head indeed accounted for at least one behavior.

In fitting the model, the research team used a probabilistic modeling approach that allowed them to understand how certain they were about each fit model parameter, an approach pioneered by co-author Vikash Mansinghka, a principal research scientist who leads MIT's Probabilistic Computing Project.

Making an atlas

In creating a model that could quantify and predict how any brain cell would represent behavior, the team initially gathered data from neurons without tracking the cells' specific identities. But a key goal of studying the worms is to understand how each cell and circuit contributes to behavior. So to apply the model's capability to each of the worm's specific neurons, which have all been previously mapped out, the team's next step was to relate neural activity and behavior for each cell on the map. Doing that required labeling each neuron with a unique color so that its activity could be associated with its identity. The team did this in dozens of freely-moving animals, which provided them with information of how almost all of the defined neurons in the worm's head related to the animal's behavior.

The atlas resulting from this work revealed many insights, more fully mapping out the neural circuits that control each of the animal's behaviors. These new findings will enable a more holistic understanding of how these behaviors are controlled, Flavell said.

"It allowed us to complete the circuits," he said. "Our hope is that as our colleagues study aspects of neural circuit function, they can refer to this atlas to obtain a fairly complete view of the key neurons involved."

Built for flexibility

Another major outcome of the team's work was the finding that while most neurons always obeyed the predictions of the model, a smaller set of neurons in the worm's brain -- about 30 percent of those that encode behavior -- was able to flexibly remap their behavior encoding, essentially taking on new jobs. The neurons in this group were reliably similar across animals, and were well connected with one another in the worm's synaptic wiring diagram.

Theoretically these remapping events could occur for any number of reasons, so the team ran further experiments to see if they could cause neurons to remap. As the worms wriggled around their dishes, the researchers applied a quick laser zap that heated the agar around the worm's head. The heat was harmless but enough to annoy the worms for a while, inducing a change in the animal's behavior state that lasted for minutes. From these recordings the team was able to see that many neurons remapped their behavioral encoding right as animals switched behavioral states.

"Behavioral information is richly expressed across the brain in many different forms -- with distinct tunings, timescales, and levels of flexibility -- that map onto the defined neuron classes of the C. elegans connectome," the authors wrote.

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Spear thrower weapon use by prehistoric females equalized the division of labor while hunting

A new study led by Archaeologist Michelle Bebber, Ph.D., an assistant professor in Kent State University's Department of Anthropology, has demonstrated that the atlatl (i.e. spear thrower) functions as an "equalizer," a finding which supports women's potential active role as prehistoric hunters.

Bebber co-authored an article "Atlatl use equalizes female and male projectile weapon velocity" which was published in the journal Nature: Scientific Reports. Her co-authors include Metin I. Eren and Dexter Zirkle (a recent Ph.D. graduate) also in the Department of Anthropology at Kent State, Briggs Buchanan of University of Tulsa, and Robert Walker of the University of Missouri.

The atlatl is a handheld, rod-shaped device that employs leverage to launch a dart, and represents a major human technological innovation used in hunting and warfare since the Stone Age. The first javelins are at least hundreds of thousands of years old; the first atlatls are likely at least tens of thousands of years old.

"One hypothesis for forager atlatl adoption over its presumed predecessor, the thrown javelin, is that a diverse array of people could achieve equal performance results, thereby facilitating inclusive participation of more people in hunting activities," Bebber said.

Bebber's study tested this hypothesis via a systematic assessment of 2,160 weapon launch events by 108 people, all novices, (many of which were Kent State students) who used both javelins and atlatls. The results are consistent with the "atlatl equalizer hypothesis," showing that the atlatl not only increases the velocity of projectile weapons relative to thrown javelins, but that the atlatl equalizes the velocity of female- and male-launched projectiles.

"This result indicates that a javelin to atlatl transition would have promoted a unification, rather than division, of labor," Bebber said. "Our results suggest that female and male interments with atlatl weaponry should be interpreted similarly, and in some archaeological contexts females could have been the atlatl's inventor."

"Many people tend to view women in the past as passive and that only males were hunters, but increasingly that does not seem to be the case," Bebber said. "Indeed, and perhaps most importantly, there seems to be a growing consilience among different fields -- archaeology, ethnography, and now modern experiments -- that women were likely active and successful hunters of game, big and small."

Since 2019, every semester Bebber takes her class outside to use the atlatl. She noticed that females picked it up very easily and could launch darts as far as the males with little effort.

"Often males became frustrated because they were trying too hard and attempting to use their strength to launch the darts," Bebber said. "However, since the atlatl functions as a simple lever, it reduces the advantage of male's generally greater muscle strength."

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Unprecedented look at what influences sea ice motion in the Arctic

A new study led by researchers at Brown offers fresh insights into the forces above and beneath the ocean surface that influence how sea ice moves and disperses in the Arctic Ocean, which is warming at over twice the rate of the global average.

The in-depth analysis reveals how local tidal currents strongly affect the movement of the ice along its journey and provides an unprecedented look at how the makeup of the seafloor is causing some of the most abrupt changes.

Data from the study can be applied to improve complex computer simulations used for forecasting Arctic sea ice conditions, and in the long-term, the results may help clarify how climate change is altering the Arctic and inform future climate predictions.

"The ice is clearly feeling the influence of the bottom of the ocean," said Daniel Watkins, a postdoctoral researcher at Brown and lead author of the new study published in Geophysical Research Letters. "The landscape at the ocean floor, like canyons and continental shelves, affects tides and other ocean currents. And as it drifts, the sea ice passes over many different undersea features. We see sharp changes in the dynamics of the sea ice as soon as it gets to those undersea features."

Using data from largest ever drifting sea-ice buoy array, along with 20 years of satellite images, the researchers examined sea ice motion as it drifted from the Arctic Ocean through a deep-water passage called the Fram Strait and eventually into the Greenland Sea. The analysis revealed the seafloor's impact on some of the most abrupt changes affecting the sea ice, like dramatic gains in speed or motions that force the ice to pack in close together or even break apart.

"What we see with this dataset is a transition from the central Arctic, where the ice is mostly moving as a whole and following wind patterns, to areas where we're seeing much stronger impacts of ocean currents," Watkins said.

The Arctic is the fastest warming part of the globe and it has long been understood that sea ice in the region plays an important role in the planet's climate. For instance, the ice acts like a reflective surface deflecting how much sunlight is absorbed by the Earth. As it disappears, more sunlight is absorbed, leading to a warmer planet. Many scientists also expect that as Arctic ice vanishes, weather across the Northern Hemisphere will be impacted, producing periods of bitter cold, punishing heat waves and disastrous floods.

With the study, the researchers wanted to delve deeper into the changes happening in this critically important part of the Earth. Much of the data for the study was gathered during the largest polar expedition in history -- the Multidisciplinary drifting Observatory for the Study of Arctic Climate.

Comprehensive research reveals sudden increases in ice speed

During the expedition, teams of researchers took turns spending a year drifting with the sea ice aboard a massive German icebreaker in the Arctic Ocean. Watkins was there for two weeks in October 2019 to help install a network of autonomous sensors around the base camp. While there, Watkins coordinated helicopter flights to remote patches of sea ice, worked with analysts to find suitable sites for instruments and buoys and deployed them on the ice.

Throughout the year-long expedition, a total of 214 buoys were deployed, including 51 during Watkins' tenure on the expedition. The study is based on GPS data transmitted from a set of 108 of the buoys that drifted from the central Arctic through the Fram Strait and into the Greenland Sea.

The major focus was on what are known as marginal ice zones in the Greenland Sea and Fram Strait, which is the transition zone between the open, ice-free ocean and the pack ice of the central arctic.

As part of their analysis, the group also analyzed satellite measurements taken from 2003 to 2020 to put the data the buoys gathered over the year adrift into historical context. The satellite data helped confirm sharp changes in ice velocity and ice motion that could only be explained by the seafloor's influence on the sea ice.

For instance, looking at the data from an area northeast of Svalbard, Norway, the researchers noticed the speed of the ice suddenly increased even though the wind hadn't changed. That meant the ice was getting pushed by the ocean currents, so the team delved deeper to find where this happens and how. They found that the sea ice speeds up where the Transpolar Drift Stream, one of the Arctic's Ocean major currents, ends and the fast-moving East Greenland Current, which forms due to a combination of the Earth's rotation and the edge of the continental shelf on the seafloor, begins. The analysis shows how the sea ice responds to different ocean currents and that the sea floor plays a role.

"In the beginning of this journey, there was almost no difference in the drift speed across the whole set of buoys," Watkins said. "Then there's essentially one day where the wind died down and the ice ran into the that boundary current and it just took off. It was like a one-day-to-the-next change in what was pushing the ice."

As next steps, the researchers plan to work with model developers to help implement the data from the study into forecasts of how the ice will move and where it will end up. They also plan to further develop an ice floe tracking tool to track the motion of individual pieces of ice. The tool would help researchers see details of ice motion that are invisible to standard approaches.

"We're hoping to understand the changing ice physics in a warming Arctic and use it to help make our models of those physics better," Watkins said.

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Scientists zero in on timing, causes of ice age mammal extinctions in southern California

The end of the last Ice Age also marked the end for more than three dozen genera of large mammals in North America, from mammoths and mastodons to bison and saber-toothed cats. Details concerning the precise timing and circumstances, however, have remained murky ever since.

A team of scientists that included Texas A&M University archaeologist Dr. Michael Waters recently focused on the well-known Rancho La Brea Tar Pits in southern California in their quest to provide answers to these questions, resulting in the most exact and detailed timeline for the extinctions that happened during the latter part of the Pleistocene period in North America, along with some foreboding insight into the area's present and future. Their work is featured on the cover of the current issue of Science.

Waters, a distinguished professor in the Department of Anthropology and director of the Center for the Study of the First Americans (CSFA), along with roughly a dozen fellow researchers, examined the timing and cause of the extinction of a variety of large mammals, known as megafauna, that got stuck in tar at Rancho La Brea, ensuring the preservation of their bones. The team used the radiocarbon dating method to date 169 bones from seven different animals -- bison, horse, camel and ground sloths as well as the carnivores that ate them, including the saber-toothed cat, dire wolf and American lion. They also compared those findings to regional pollen and charcoal records along with continent-wide data on human and large mammal populations.

Armed with their new data, the researchers subsequently used time-series modeling to produce the most detailed chronobiology to date, showing the relationships between climate and vegetation change, fire activity, human demographics and megafauna extinctions -- groundbreaking results they report in the Aug. 18 edition of the world-leading academic journal.

Waters says the team's findings reveal that Ice Age mammal populations in southern California were steady from 15,000 to around 13,250 years ago. Afterward, there was a sharp decline in the population of the seven animals studied, and they all became extinct between 13,070 to 12,900 years ago.

In an interesting modern-day parallel, this extinction event corresponds with a change in the environment from 13,300 to 12,900 years ago marked by warming and drying that made the land more vulnerable to fires in southern California. Charcoal records show that fires increased around 13,500 years ago and peaked between 13,200 and 12,900 years ago. Studies show that humans arrived in North America's Pacific coast 16,000 to 15,000 years ago and lived alongside the megafauna for 2,000 to 3,000 years before their extinction.

While humans hunted animals during this period, Waters says the impact of hunting on the demise of the megafauna likely was minor because of the low population of humans on the landscape. However, the fires would have been devastating, resulting in the loss of habitat causing the rapid decline and extinction of the megafauna in southern California. The study suggests these fires were ignited by humans, which had increased in number by that time.

"Fire is a way that small numbers of humans can have a large impact over a broad area," said Waters, who also cautions that climate changes observed in present-day California are similar to those of the late Pleistocene.

"This study has implications for the changes we see in southern California today," Waters added. "The temperatures are rising, and the area is drying. We also see a dramatic increase in fires. It appears that history may be repeating itself."

While Waters acknowledges that this is the story of extinction at Rancho La Brea, he says it has the potential to offer insights into when extinctions happened across all of North America.

"Mammoths and mastodons survived in many parts of North America until around 12,700 years ago," he added. "These animals were hunted by the Clovis people between about 13,000 and 12,700 years ago. We are now dating megafauna remains from other locations to give a broader understanding of the Rancho La Brea research in the context of North America."

The museum at La Brea Tar Pits holds the world's largest collection of fossils from the Ice Age and has been central to the study of animal and plant life at the end of the Pleistocene epoch for more than a century. Its naturally occurring asphalt pools entrapped and preserved the bones of thousands of individual animals representing dozens of megafaunal species during the last 60,000 years, enabling scientists to determine when different species disappeared from the ecosystem and why.

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Brain recordings capture musicality of speech -- with help from Pink Floyd

As the chords of Pink Floyd's "Another Brick in the Wall, Part 1," filled the surgery suite, neuroscientists at Albany Medical Center diligently recorded the activity of electrodes placed on the brains of patients undergoing epilepsy surgery.

The goal? To capture the electrical activity of brain regions tuned to attributes of the music -- tone, rhythm, harmony and words -- to see if they could reconstruct what the patient was hearing.

More than a decade later, after detailed analysis of data from 29 such patients by neuroscientists at the University of California, Berkeley, the answer is clearly yes.

The phrase "All in all it was just a brick in the wall" comes through recognizably in the reconstructed song, its rhythms intact, and the words muddy, but decipherable. This is the first time researchers have reconstructed a recognizable song from brain recordings.

The reconstruction shows the feasibility of recording and translating brain waves to capture the musical elements of speech, as well as the syllables. In humans, these musical elements, called prosody -- rhythm, stress, accent and intonation -- carry meaning that the words alone do not convey.

Because these intracranial electroencephalography (iEEG) recordings can be made only from the surface of the brain -- as close as you can get to the auditory centers -- no one will be eavesdropping on the songs in your head anytime soon.

But for people who have trouble communicating, whether because of stroke or paralysis, such recordings from electrodes on the brain surface could help reproduce the musicality of speech that's missing from today's robot-like reconstructions.

"It's a wonderful result," said Robert Knight, a neurologist and UC Berkeley professor of psychology in the Helen Wills Neuroscience Institute who conducted the study with postdoctoral fellow Ludovic Bellier. "One of the things for me about music is it has prosody and emotional content. As this whole field of brain machine interfaces progresses, this gives you a way to add musicality to future brain implants for people who need it, someone who's got ALS or some other disabling neurological or developmental disorder compromising speech output. It gives you an ability to decode not only the linguistic content, but some of the prosodic content of speech, some of the affect. I think that's what we've really begun to crack the code on."

As brain recording techniques improve, it may be possible someday to make such recordings without opening the brain, perhaps using sensitive electrodes attached to the scalp. Currently, scalp EEG can measure brain activity to detect an individual letter from a stream of letters, but the approach takes at least 20 seconds to identify a single letter, making communication effortful and difficult, Knight said.

"Noninvasive techniques are just not accurate enough today. Let's hope, for patients, that in the future we could, from just electrodes placed outside on the skull, read activity from deeper regions of the brain with a good signal quality. But we are far from there," Bellier said.

Bellier, Knight and their colleagues reported the results today in the journal PLOS Biology, noting that they have added "another brick in the wall of our understanding of music processing in the human brain."

Reading your mind? Not yet.

The brain machine interfaces used today to help people communicate when they're unable to speak can decode words, but the sentences produced have a robotic quality akin to how the late Stephen Hawking sounded when he used a speech-generating device.

"Right now, the technology is more like a keyboard for the mind," Bellier said. "You can't read your thoughts from a keyboard. You need to push the buttons. And it makes kind of a robotic voice; for sure there's less of what I call expressive freedom."

Bellier should know. He has played music since childhood -- drums, classical guitar, piano and bass, at one point performing in a heavy metal band. When Knight asked him to work on the musicality of speech, Bellier said, "You bet I was excited when I got the proposal."

In 2012, Knight, postdoctoral fellow Brian Pasley and their colleagues were the first to reconstruct the words a person was hearing from recordings of brain activity alone.

More recently, other researchers have taken Knight's work much further. Eddie Chang, a UC San Francisco neurosurgeon and senior co-author of the 2012 paper, has recorded signals from the motor area of the brain associated with jaw, lip and tongue movements to reconstruct the speech intended by a paralyzed patient, with the words displayed on a computer screen.

That work, reported in 2021, employed artificial intelligence to interpret the brain recordings from a patient trying to vocalize a sentence based on a set of 50 words.

While Chang's technique is proving successful, the new study suggests that recording from the auditory regions of the brain, where all aspects of sound are processed, can capture other aspects of speech that are important in human communication.

"Decoding from the auditory cortices, which are closer to the acoustics of the sounds, as opposed to the motor cortex, which is closer to the movements that are done to generate the acoustics of speech, is super promising," Bellier added. "It will give a little color to what's decoded."

For the new study, Bellier reanalyzed brain recordings obtained in 2012 and 2013 as patients were played an approximately 3-minute segment of the Pink Floyd song, which is from the 1979 album The Wall. He hoped to go beyond previous studies, which had tested whether decoding models could identify different musical pieces and genres, to actually reconstruct music phrases through regression-based decoding models.

Bellier emphasized that the study, which used artificial intelligence to decode brain activity and then encode a reproduction, did not merely create a black box to synthesize speech. He and his colleagues were also able to pinpoint new areas of the brain involved in detecting rhythm, such as a thrumming guitar, and discovered that some portions of the auditory cortex -- in the superior temporal gyrus, located just behind and above the ear -- respond at the onset of a voice or a synthesizer, while other areas respond to sustained vocals.

The researchers also confirmed that the right side of the brain is more attuned to music than the left side.

"Language is more left brain. Music is more distributed, with a bias toward right," Knight said.

"It wasn't clear it would be the same with musical stimuli," Bellier said. "So here we confirm that that's not just a speech-specific thing, but that's it's more fundamental to the auditory system and the way it processes both speech and music."

Knight is embarking on new research to understand the brain circuits that allow some people with aphasia due to stroke or brain damage to communicate by singing when they cannot otherwise find the words to express themselves.

Read more at Science Daily