Why coffee beans taste different

Differences in the flavours of Arabica coffee varieties aren’t because of variations in individual genes. Rather, they seem to be mainly the result of wholesale swapping, deletion and rearrangement.... The most complete sequencing yet of Coffea arabica’s genome reveals that the levels of single-‘letter’ variations in the plant’s DNA “are anywhere from 10 to 100 times lower than any other species”, says plant geneticist and study co-author Michele Morgante.

Nature
 Nature Communications paper

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How chronic stress harms the gut

Researchers have revealed one of the mind-body connections that links stress to gastrointestinal flare-ups. In mice, Lactobacillus bacteria  which naturally occur in the gut and proliferate under stressful conditions produce a chemical that disrupts teh production of  intestine-protecting cells. The team also found elevated levels of Lactobacillus, and the harmful chemical, in the faeces of people with depression. When we suffer from stress, our gut microbiome is also suffering from stress. 

Nature
 Cell Metabolism 

Science can only ascertain what is, but not what should be, and outside its domain value judgments of all kinds remain 

Rare decay of the Higgs boson may point to physics beyond the Standard Model

Particle physicists have detected a novel decay of the Higgs boson for the first time, revealing a slight discrepancy in the predictions of the Standard Model and perhaps pointing to new physics beyond it. 

For this run the energy in the collision of the two protons was 13 trillion electron-volts, just below the machine's current maximum, which in more relatable units is 2.1 microjoules. That's about the kinetic energy of the average mosquito, or a grain of salt, traveling one meter per second.

Theory predicts that about 15 times per 10,000 decays, the Higgs boson should decay into a Z boson and a photon, the rarest decay in the Standard Model. It does so by first producing a pair of top quarks, or a pair of W bosons, which themselves then decay into the Z and photon.

The Atlas/CMS collaboration, work from more than 9,000 scientists, found a "branching ratio," or fraction of decays of 34 times per 10,000 decays, plus or minus 11 per 10,000—2.2 times the theoretical value.

The measured fraction is too large—3.4 standard deviations above the theoretical value, a number still too small to rule out a statistical fluke. Still, the relatively large difference hints at the possibility of a meaningful discrepancy from theory that could be due to physics beyond the Standard Model—new particles that are the intermediaries other than the top quark and W bosons.
One possibility for physics beyond the Standard Model is supersymmetry, the theory that posits a symmetry—a relationship—between particles of a half-spin, called fermions, and integer spin, called bosons, with every known particle having a partner with a spin differing by a half-integer.

Many theoretical physicists have long been advocates of supersymmetry as it would solve many conundrums that plague the Standard Model, such as the large difference (1024) between the strengths of the weak force and gravity, or why the mass of the Higgs boson, about 125 gigaelectron-volts (GeV), is so much less than the grand unification energy scale of about 1016 GeV.

G. Aad et al, Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.132.021803

Part 2

Scientists discover the moon is shrinking, causing landslides and instability in lunar south pole

Earth's moon shrank more than 150 feet in circumference as its core gradually cooled over the last few hundred million years. In much the same way a grape wrinkles when it shrinks down to a raisin, the moon also develops creases as it shrinks. But unlike the flexible skin on a grape, the moon's surface is brittle, causing faults to form where sections of crust push against one another.

A team of scientists discovered evidence that this continuing shrinkage of the moon led to notable surface warping in its south polar region—including areas that NASA proposed for crewed Artemis III landings. Because fault formation caused by the moon's shrinking is often accompanied by seismic activity like moonquakes, locations near or within such fault zones could pose dangers to future human exploration efforts.

In a paper published in The Planetary Science Journal, the team linked a group of faults located in the moon's south polar region to one of the most powerful moonquakes recorded by Apollo seismometers over 50 years ago. Using models to simulate the stability of surface slopes in the region, the team found that some areas were particularly vulnerable to landslides from seismic shaking.

Shallow moonquakes occur near the surface of the moon, just a hundred or so miles deep into the crust. Similar to earthquakes, shallow moonquakes are caused by faults in the moon's interior and can be strong enough to damage buildings, equipment and other human-made structures.

But unlike earthquakes, which tend to last only a few seconds or minutes, shallow moonquakes can last for hours and even a whole afternoon.

Watters et al, Tectonics and Seismicity of the Lunar South Polar Region, The Planetary Science Journal (2024). DOI: 10.3847/PSJ/ad1332

How HIV smuggles its genetic material into the cell nucleus

Each year, about 1 million individuals worldwide become infected with HIV, the virus that causes AIDS. To replicate and spread the infection, the virus must smuggle its genetic material into the cell nucleus and integrate it into a chromosome.

Researchers have now discovered that its capsid has evolved into a molecular transporter. As such, it can directly breach a crucial barrier, which normally protects the cell nucleus against viral invaders. This way of smuggling keeps the viral genome invisible to anti-viral sensors in the cytoplasm. Their study is published in Nature. 

Forty years after the human immunodeficiency virus (HIV) was discovered as the cause of AIDS, we have therapies that effectively keep the pathogen under control, but there is still no cure. The virus infects certain immune cells and hijacks their genetic program in order to multiply and replicate its own genetic material. The infected cells then produce the next generation of viruses until they are finally destroyed. The immunodeficiency symptoms of AIDS result from the massive loss of immune cells that normally fight viruses and other pathogens.
To use the host cell's resources, HIV must smuggle its genetic material through cellular defense lines into the cell nucleus. The nucleus, however, is closely guarded. Its nuclear envelope prevents unwanted proteins or harmful viruses from entering the nucleus and macromolecules from an uncontrolled escape. Yet, selected proteins can pass because the barrier is not hermetically sealed.

Thousands of tiny nuclear pores in the nuclear envelope provide a passageway. They control these transport processes with the help of importins and exportins—molecular transporters that capture cargoes with valid molecular "passcodes" and deliver them through the nuclear pore channel. A "smart" material turns these pores into one of nature's most efficient sorting and transport machines.

Part 1

This "smart" material, called FG phase, is jelly-like and impenetrable for most macromolecules. It fills and blocks the nuclear pore channel. Importins and exportins, however, can pass through because their surfaces are optimized for sliding through an FG phase.

The cell's border control in the FG phase happens extremely fast—within milliseconds. Likewise, its transport capacity is enormous: A single nuclear pore can transfer up to 1,000 transporters per second through its channel. Even with such a high traffic density, the barrier of nuclear pores remains intact and keeps suppressing unwanted border crossings. HIV, however, subverts this control.
HIV packages its genome into a capsid. Recent evidence suggests that the genome stays inside the capsid until it reaches the nucleus, and thus also when passing the nuclear pore. But there is a size problem.
The central pore channel is 40 to 60 nanometers wide. The capsid has a width of about 60 nanometers and could just squeeze through the pore.

However, a normal cellular cargo would still be covered by a transporter layer that adds at least another ten nanometers. The HIV capsid would then be 70 nanometers wide—too big for a nuclear pore. Nevertheless, cryo-electron tomography has shown that the HIV capsid gets into the nuclear pore. But how this happens has been so far a mystery in HIV infection.

 Liran Fu et al, HIV-1 capsids enter the FG phase of nuclear pores like a transport receptor, Nature (2024). DOI: 10.1038/s41586-023-06966-w

Part 2

Stars travel more slowly at Milky Way's edge: Galaxy's core may contain less dark matter than previously estimated

By clocking the speed of stars throughout the Milky Way galaxy,  physicists have found that stars further out in the galactic disk are traveling more slowly than expected compared to stars that are closer to the galaxy's center. The findings raise a surprising possibility: The Milky Way's gravitational core may be lighter in mass, and contain less dark matter, than previously thought.

The new results are based on the researchers' analysis of data taken by the Gaia and APOGEE instruments. Gaia is an orbiting space telescope that tracks the precise location, distance, and motion of more than 1 billion stars throughout the Milky Way galaxy, while APOGEE is a ground-based survey.

The physicists analyzed Gaia's measurements of more than 33,000 stars, including some of the farthest stars in the galaxy, and determined each star's "circular velocity," or how fast a star is circling in the galactic disk, given the star's distance from the galaxy's center.

The scientists plotted each star's velocity against its distance to generate a rotation curve—a standard graph in astronomy that represents how fast matter rotates at a given distance from the center of a galaxy. The shape of this curve can give scientists an idea of how much visible and dark matter is distributed throughout a galaxy.

What they were really surprised to see was that this curve remained flat, flat, flat out to a certain distance, and then it started tanking. This means the outer stars are rotating a little slower than expected, which is a very surprising result.

The team translated the new rotation curve into a distribution of dark matter that could explain the outer stars' slow-down, and found the resulting map produced a lighter galactic core than expected. That is, the center of the Milky Way may be less dense, with less dark matter, than scientists have thought.

 Xiaowei Ou et al, The dark matter profile of the Milky Way inferred from its circular velocity curve, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae034

Writing by hand may increase brain connectivity more than typing on a keyboard

As digital devices progressively replace pen and paper, taking notes by hand is becoming increasingly uncommon in schools and universities. Using a keyboard is recommended because it's often faster than writing by hand. However, the latter has been found to improve spelling accuracy and memory recall.

To find out if the process of forming letters by hand resulted in greater brain connectivity, researchers  now investigated the underlying neural networks involved in both modes of writing.

They showed that when writing by hand, brain connectivity patterns are far more elaborate than when typewriting on a keyboard. Such widespread brain connectivity is known to be crucial for memory formation and for encoding new information and, therefore, is beneficial for learning.

The researchers collected EEG data from 36 university students who were repeatedly prompted to either write or type a word that appeared on a screen. When writing, they used a digital pen to write in cursive directly on a touchscreen. When typing they used a single finger to press keys on a keyboard.

High-density EEGs, which measure electrical activity in the brain using 256 small sensors sewn in a net and placed over the head, were recorded for five seconds for every prompt.

Connectivity of different brain regions increased when participants wrote by hand, but not when they typed. These findings suggest that visual and movement information obtained through precisely controlled hand movements when using a pen contribute extensively to the brain's connectivity patterns that promote learning.

Although the participants used digital pens for handwriting, the researchers said that the results are expected to be the same when using a real pen on paper.

Their findings demonstrate the need to give students the opportunity to use pens, rather than having them type during class, the researchers said.

Handwriting but not Typewriting Leads to Widespread Brain Connectivity: A High-Density EEG Study with Implications for the Classroom, Frontiers in Psychology (2024). DOI: 10.3389/fpsyg.2023.1219945

On tropical coasts, hermit crabs are now making their homes in plastic waste

Terrestrial hermit crabs are soft-bodied crustaceans that live near water in the world's tropical areas. Without any natural protection of their own, these crabs normally find shelter in discarded mollusk shells. But a number of terrestrial hermit crab species are beginning to opt for artificial shells frequently consisting of plastic objects found in beach trash.

New research on this topic, described in a short communication by a team from the University of Warsaw's Biological and Chemical Research Center and the department of Zoology at Poland's Poznań University of Life Sciences, appears in Science of the Total Environment.

Plastic pollution, which is increasing, already comprises 85% of marine pollution worldwide. Existing research shows that most of the plastic pollution in Earth's oceans arrives there via rivers, leading to plastic waste accumulation on coastlines.

Terrestrial hermit crabs (Coenobitidae) live on all the world's tropical coastlines, and typically acquire empty shells of gastropods to protect their soft abdominal region, known as pleon. The shells protect them from predators and also keep their pleon from drying out.

Studies on the crabs' selection of shells have shown the main factors include chemical signals gleaned from shells; proximity of predators; quality of shells; and rate of individual crab growth. It has also been shown that shells play a role in sexual signaling, as the size and state of male crabs' shells affect females' mate choices.

Part 1

In discussing possible reasons for this behavior among Coenobitidae, the team notes the environmental availability of plastic waste, along with the growing scarcity of gastropod shells due to localized human activities. The researchers also suggest factors involved in individual choice, including:

• Attractiveness of artificial materials to mating females
• Lighter artificial shell weights that might benefit hermit crabs' energy
• An odor cue of dimethyl sulfide, found in both natural shells and marine waste; and
• The possibility that artificial shells may serve more efficiently as camouflage in polluted areas, given that shell selection is often made to blend into the localized environment.

These are all topics for further investigation.

"Are artificial shells setting the scene for a novel evolutionary trajectory in hermit crabs, or are they an ecological and evolutionary trap of the Anthropocene?" the researchers ask.

While this new behavior might be considered a clever adaptation, the main factor behind it is undeniable. In that vein, what this habit ultimately means for the evolution of terrestrial hermit crabs remains to be studied.

 Zuzanna Jagiello et al, The plastic homes of hermit crabs in the Anthropocene, Science of the Total Environment (2024). DOI:/10.1016/j.scitotenv.2023.168959

Part 2

Coenobita purpureus with artificial shells: (A) plastic cap, (B) bulb fragment, (C) metal cap with a glass bottle fragment. Credit: Shawn Miller / Science of the Total Environment (2024). DOI:/10.1016/j.scitotenv.2023.168959

Part 3

How obesity dismantles our mitochondria: Study reveals key mechanism behind obesity-related metabolic dysfunction

The number of people with obesity has nearly tripled since 1975, resulting in a worldwide epidemic. While lifestyle factors like diet and exercise play a role in the development and progression of obesity, scientists have come to understand that obesity is also associated with intrinsic metabolic abnormalities.

Now researchers  have shed new light on how obesity affects our mitochondria, the all-important energy-producing structures of our cells.

In a study published in Nature Metabolism, the researchers found that when mice were fed a high-fat diet, mitochondria within their fat cells broke apart into smaller mitochondria with reduced capacity for burning fat. Further, they discovered that this process is controlled by a single gene. By deleting this gene from the mice, they were able to protect them from excess weight gain, even when they ate the same high-fat diet as other mice.

Caloric overload from overeating can lead to weight gain and also triggers a metabolic cascade that reduces energy burning, making obesity even worse.

In the case of caloric imbalances like obesity, the ability of fat cells to burn energy starts to fail, which is one reason why it can be difficult for people with obesity to lose weight.

In addition to discovering this metabolic effect, they also discovered that it is driven by the activity of a single molecule, called RaIA. RaIA has many functions, including helping break down mitochondria when they malfunction. The new research suggests that when this molecule is overactive, it interferes with the normal functioning of mitochondria, triggering the metabolic issues associated with obesity. In essence, chronic activation of RaIA appears to play a critical role in suppressing energy expenditure in obese adipose tissue. By understanding this mechanism, we're one step closer to developing targeted therapies that could address weight gain and associated metabolic dysfunctions by increasing fat burning.

 Nature Metabolism (2024). DOI: 10.1038/s42255-024-00978-0

Research reveals quantum entanglement among quarks

Collisions of high energy particles produce "jets" of quarks, anti-quarks, or gluons. Due to the phenomenon called confinement, scientists cannot directly detect quarks. Instead, the quarks from these collisions fragment into many secondary particles that can be detected.

Scientists recently addressed jet production using quantum simulations. They found that the propagating jets strongly modify the quantum vacuum—the quantum state with the lowest possible energy. In addition, the produced quarks retain quantum entanglement, the linkage between particles across distances. This finding, published in Physical Review Letters, means that scientists can now study this entanglement in experiments.

Adrien Florio et al, Real-Time Nonperturbative Dynamics of Jet Production in Schwinger Model: Quantum Entanglement and Vacuum Modification, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.021902

Researchers slow down light in metasurfaces with record low loss

The speed of light can be intentionally reduced in various media. Various techniques have been developed over the years to slow down light, including electromagnetically induced transparency (EIT), Bose-Einstein condensate (BEC), photonic crystals, and stimulated Brillouin scattering (SBS).

Notably, researchers from Harvard, led by Lene Vestergaard Hau, reduced light speed to 17 m/s in an ultracold atomic gas using EIT, which sparked the interest in exploring EIT analogs in metasurfaces, a transformative platform in optics and photonics.

Despite the benefits, slow-light structures face a significant challenge: Loss, which limits storage time and interaction length. This issue is particularly severe for metasurface analogs of EIT due to scattering loss of nanoparticles and sometimes absorption loss of materials.

In a study published in Nano Letters, researchers introduced a novel strategy to realize a metasurface analog of EIT while effectively suppressing losses.

Unlike conventional metasurface analogs of EIT induced by coupling between two localized resonances supported by closely packed meta-atoms, or between localized and collective resonances, the researchers proposed a new type called "collective EIT-like resonance," which is induced by the coupling between two collective resonances—a Mie electric dipole surface lattice resonance (ED-SLR) and an in-plane or out-of-plane electric quadrupole SLR (EQ-SLR).

Using silicon metasurfaces with a 100 nm-thick nanodisk array, they demonstrated collective EIT-like resonances with a quality factor exceeding 2,750, more than five times the state-of-the-art. In practical terms, light passing through the silicon nanodisks can be slowed down by more than 10,000 times, with a reduction in loss by more than five times compared to existing methods.

The departure from the conventional belief that metasurface performance depends on how closely meta-atoms can be placed. The researchers explored the extreme regime of zero distance between meta-atoms, essentially merging them into one. Unlike conventional methods, their approach allowed the tuning of surface lattice resonances to overlap spectrally, enabling the realization of metasurface analogs of EIT.

Furthermore, the researchers demonstrated a BIC-characterized collective EIT-like resonance utilizing the transition between the in-plane EQ-SLR and the bound state in the continuum (BIC). This suggested the potential to slow down light by an arbitrarily large factor while maintaining a growing quality factor.

 Xueqian Zhao et al, Ultrahigh-Q Metasurface Transparency Band Induced by Collective–Collective Coupling, Nano Letters (2024). DOI: 10.1021/acs.nanolett.3c04174

The first observation of a material exhibiting a supersolid phase of matter

Through experimental research, a team of physicists affiliated with multiple institutions in China has observed a material in a supersolid phase of matter for the first time. In their paper published in the journal Nature, the group describes the experiments they conducted to accomplish this feat and its implications. Nature has published a Research Briefing in the same journal issue outlining the work done by the team on this effort.

A supersolid is a seemingly contradictory material—it is defined as rigid, but also has superfluidity, in which a liquid flows without friction. In the 1970s, theoretical work by Anthony Leggett suggested that such a material might be possible. But until now, no one has been able to find it in nature or synthesize it in the lab.

To create a supersolid, the researchers involved in this new study started with a compound called NBCP—it has the unique attribute of atoms arranged in triangular lattices. This means, the research team found, that if it is placed within a magnetic field, all its atoms will spin in the same direction.

But when the magnet is removed, the atoms all try to orient themselves with a spin opposite that of their neighbor—but because they are arranged in a triangle, "frustration" arises because of the limited possible orientations. This observation suggested that under the right conditions, NBCP could exist as a supersolid.

To create the right conditions, the researchers built an apparatus to measure the magnetocaloric effect as the material was exposed to a magnetic field without fear of heat leaks. This allowed them to map the entropy state, which in turn allowed them to detect the spin states of the atoms and their transitions. They compared the findings with theoretical calculations and determined that they were on the right track. They then carried out neutron diffraction measurements and compared them to theoretical calculations, and once again found agreement. Together, such measurements allowed them to conclude that they had observed a material in its supersolid state. The observation is expected to open new possibilities for studying quantum phenomena and simulating novel materials.

Junsen Xiang et al, Giant magnetocaloric effect in spin supersolid candidate Na2BaCo(PO4)2, Nature (2024). DOI: 10.1038/s41586-023-06885-w

Spin supersolid with giant magnetocaloric effect promises a new route to extreme cooling, Nature (2024). DOI: 10.1038/d41586-023-04102-2. www.nature.com/articles/d41586-023-04102-2

Brains Not Required
Simple cells, not just highly specialized neurons, can exhibit basic cognitive abilities such as memory, learning, and problem-solving. Tufts University biologist Michael Levin trained flatworms to expect yummy liver treats at a certain location in their dish. Even after he decapitated the worms (don’t worry! They regrew their heads), the worms could remember where to go for a liver snack. Researchers suspect that body cells are able to use weak electric fields to store information.

Why this is so cool: Plants, slime molds, and single-celled organisms also demonstrate surprising abilities to sense and respond to their environment, challenging the idea that intelligence is limited to creatures with brains. Weak fields of bioelectricity could be how cells communicate with each other and transmit information throughout the body.

What the experts say: "All intelligence is really collective intelligence, because every cognitive system is made of some kind of parts,” says Levin, who also studied the role of bioelectricity in frog development and the origin of cancer.

 body cells are able to use weak electric fields to store information. 

DNA particles that mimic viruses hold promise as vaccines

Using a virus-like delivery particle made from DNA, researchers have created a vaccine that can induce a strong antibody response against SARS-CoV-2.

The vaccine, which has been tested in mice, consists of a DNA scaffold that carries many copies of a viral antigen. This type of vaccine, known as a particulate vaccine, mimics the structure of a virus. Most previous work on particulate vaccines has relied on protein scaffolds, but the proteins used in those vaccines tend to generate an unnecessary immune response that can distract the immune system from the target.

In the mouse study, the researchers found that the DNA scaffold does not induce an immune response, allowing the immune system to focus its antibody response on the target antigen.

This approach, which strongly stimulates B cells (the cells that produce antibodies), could make it easier to develop vaccines against viruses that have been difficult to target, including HIV and influenza, as well as SARS-CoV-2, the researchers say. Unlike T cells, which are stimulated by other types of vaccines, these B cells can persist for decades, offering long-term protection.

Enhancing antibody responses by multivalent antigen display on thymusindependent DNA origami scaffolds, Nature Communications (2024). DOI: 10.1038/s41467-024-44869-0

Study finds gut microbiota influence severity of respiratory viral infection

The composition of microbiota found in the gut influences how susceptible mice are to respiratory virus infections and the severity of these infections, according to new research by researchers.

The findings, published in the journal Cell Host & Microbe, report that segmented filamentous bacteria, a bacterial species found in the intestines, protected mice against influenza virus infection when these bacteria were either naturally acquired or administered.

This protection against infection also applied to respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. To maintain this protection, the study noted that segmented filamentous bacteria required immune cells in the lungs called basally resident alveolar macrophages.

In this study, the researchers investigated how differences in specific microbial species can impact outcomes of respiratory virus infections and how they might do so, which hasn't been well defined previously. They studied mice with discrete microbiome differences and mice differing in only the presence or absence of segmented filamentous bacteria. Viral titers in the lung were measured several days after infection and varied significantly depending on the nature of the microbiome of the different animal groups.

These findings uncover complex interactions that mechanistically link the intestinal microbiota with the functionality of basally resident alveolar macrophages and severity of respiratory virus infection.

Intestinal microbiota programming of alveolar macrophages influences severity of respiratory viral infection, Cell Host & Microbe (2024). DOI: 10.1016/j.chom.2024.01.002. www.cell.com/cell-host-microbe … 1931-3128(24)00006-4

Neanderthals and humans lived side by side in Northern Europe 45,000 years ago, genetic analysis finds

A genetic analysis of bone fragments unearthed at an archaeological site in central Germany shows conclusively that modern humans—Homo sapiens—had already reached Northern Europe 45,000 years ago, overlapping with Neanderthals for several thousand years before the latter went extinct.

The findings establish that the site near Ranis, Germany, which is known for its finely flaked, leaf-shaped stone tool blades, is among the oldest confirmed sites of modern human Stone Age culture in north central and northwestern Europe.

The evidence that Homo sapiens and Homo neanderthalensis lived side by side is consistent with genomic evidence that the two species occasionally interbred. It also feeds the suspicion that the invasion of Europe and Asia by modern humans some 50,000 years ago helped drive Neanderthals, which had occupied the area for more than 500,000 years, to extinction.

The genetic analysis, along with an archaeological and isotopic analysis and radiocarbon dating of the Ranis site, are detailed in a trio of papers appearing in the journals Nature and Nature Ecology and Evolution.

Jean-Jacques Hublin, Homo sapiens reached the higher latitudes of Europe by 45,000 years ago, Nature (2024). DOI: 10.1038/s41586-023-06923-7. www.nature.com/articles/s41586-023-06923-7

Stable isotopes show Homo sapiens dispersed into cold steppes ~45,000 years ago at Ilsenhöhle in Ranis, Germany, Nature (2024). DOI: 10.1038/s41559-023-02318-z , www.nature.com/articles/s41559-023-02318-z

The ecology, subsistence and diet of ~45,000-year-old Homo sapiens at Ilsenhöhle in Ranis, Germany, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-023-02303-6 , www.nature.com/articles/s41559-023-02303-6

https://phys.org/news/2024-01-neanderthals-humans-side-northern-eur...

Scientists pinpoint growth of brain's cerebellum as key to evolution of bird flight

Evolutionary biologists  report they have combined PET scans of modern pigeons along with studies of dinosaur fossils to help answer an enduring question in biology: How did the brains of birds evolve to enable them to fly?

The answer, they say, appears to be an adaptive increase in the size of the cerebellum in some fossil vertebrates. The cerebellum is a brain region responsible for movement and motor control.

The research findings are published in the Jan. 31 issue of the Proceedings of the Royal Society B.

The researchers performed positron emission tomography, or PET, imaging scans, the same technology commonly used on humans, to compare activity in 26 regions of the brain when the bird was at rest and immediately after it flew for 10 minutes from one perch to another. They scanned eight birds on different days. PET scans use a compound similar to glucose that can be tracked to where it's most absorbed by brain cells, indicating increased use of energy and thus activity. The tracker degrades and gets excreted from the body within a day or two. Of the 26 regions, one area—the cerebellum—had statistically significant increases in activity levels between resting and flying in all eight birds. Overall, the level of activity increase in the cerebellum differed by more than two standard statistical deviations, compared with other areas of the brain. The researchers also detected increased brain activity in the so-called optic flow pathways, a network of brain cells that connect the retina in the eye to the cerebellum. These pathways process movement across the visual field.

What was new in this research was linking the cerebellum findings of flight-enabled brains in modern birds to the fossil record that showed how the brains of birdlike dinosaurs began to develop brain conditions for powered flight.

Quantitative functional imaging of the pigeon brain: implications for the evolution of avian powered flight, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2023.2172. royalsocietypublishing.org/doi … .1098/rspb.2023.2172

Brain changes behind pain sensitivity may affect older women more

A new study has found that the brain system enabling us to inhibit our own pain changes with age, and that gender-based differences in those changes may lead females to be more sensitive to moderate pain than males as older adults.

Researchers used fMRI scans to examine brain responses in men and women who had rated the intensity and unpleasantness of pain during exposure to increasing levels of heat. The results suggested that established gender differences in pain perception could likely be traced at least in part to this brain network, and offered new evidence that those gender differences may become more disparate with age.

Michelle D. Failla et al, Gender Differences in Pain Threshold, Unpleasantness, and Descending Pain Modulatory Activation Across the Adult Life Span: A Cross Sectional Study, The Journal of Pain (2023). DOI: 10.1016/j.jpain.2023.10.027

How synthetic biology is helping us: Researchers engineer viruses to kill deadly pathogens

Researchers have successfully coaxed a deadly pathogen to destroy itself from the inside out.

In a new study, researchers modified DNA from a bacteriophage or "phage," a type of virus that infects and replicates inside of bacteria. Then, the research team put the DNA inside Pseudomonas aeruginosa (P. aeruginosa), a deadly bacterium that is also highly resistant to antibiotics. Once inside the bacterium, the DNA bypassed the pathogen's defense mechanisms to assemble into virions, which sliced through the bacterium's cell to kill it.

Building on a growing interest in "phage therapies," the experimental work represents a critical step toward engineering designer viruses as new therapeutics to kill antibiotic-resistant bacteria. It also reveals vital information about the inner workings of phages, a little-studied area of biology.

The study, "A synthetic biology approach to assemble and reboot clinically relevant Pseudomonas aeruginosa tailed phages," was published in the journal Microbiology Spectrum.

Not only did the phage kill the bacteria, the bacteria also ejected billions more phages. These phages can then be used to kill other bacteria, like those causing an infection.

A synthetic biology approach to assemble and reboot clinically relevant Pseudomonas aeruginosa tailed phages, Microbiology Spectrum (2024). DOI: 10.1128/spectrum.02897-23

Study finds 1 in 10 veterans diagnosed with dementia may instead have cognitive decline from cirrhosis

As many as 10% of older U.S. veterans diagnosed with dementia may suffer instead from reversible cognitive decline caused by advanced liver disease, according to an analysis from the Virginia Commonwealth University's School of Medicine and the Richmond VA Medical Center.

It can be difficult for physicians to differentiate dementia from the cognitive decline caused by cirrhosis, called hepatic encephalopathy. If undetected, patients may not receive appropriate treatment that can reverse or halt the impairment. The study, published in the journal JAMA Network Open, sought to learn more about the prevalence and risk factors of undiagnosed cirrhosis and potential encephalopathy in veterans with dementia. The findings suggest that physicians treating veterans with dementia, even without a cirrhosis diagnosis, should consider assessing their patients for liver disease. Identifying cirrhosis early on may unveil reversible causes of cognitive impairment, potentially improving the lives of these patients.

Hepatic encephalopathy is a nervous system disorder brought on by cirrhosis, an advanced form of liver disease in which patients experience severe scarring of the liver. When the liver doesn't work properly, toxins build up in the blood. These toxins can travel to the brain and affect brain function, leaving patients confused or delirious. Widely available medications can readily rid the body of toxins and reverse this condition, but without treatment, patients can lapse into coma or die.

Undiagnosed Cirrhosis and Hepatic Encephalopathy in a National Cohort of Veterans With Dementia, JAMA Network Open (2024). DOI: 10.1001/jamanetworkopen.2023.53965

Surgeons' choice of skin disinfectant impacts infection risk, Canadian-American study shows

Does the type of solution used by surgeons to disinfect skin before surgery impact the risk of surgical site infection? According to new research from an international trial jointly led by McMaster University and the University of Maryland School of Medicine—yes, it does!

Researchers of the PREPARE trial, which enrolled nearly 8,500 participants at 25 hospitals in Canada and the United States, found the use of iodine povacrylex in alcohol to disinfect a patient's skin could prevent surgical site infection in thousands of patients undergoing surgery for a closed fracture each year. The findings, published in The New England Journal of Medicine, are poised to have many hospitals consider a policy change to the use of iodine povacrylex in alcohol for fracture surgeries.

The trial included 6,785 patients undergoing surgery to treat a closed lower extremity or pelvic fracture and 1,700 patients undergoing surgery to treat an open fracture. Closed fractures occur when the bone is broken, but the skin is intact. Open fractures have an exceptionally high risk of infection due to the open wound and bone being exposed to environmental bacteria for hours before surgery. Researchers compared the two most commonly used antiseptic products in the United States and Canada. Patients with closed fractures randomized to receive 0.7% iodine povacrylex in 74% isopropyl alcohol for skin antisepsis experienced fewer post-operative surgical site infections than those randomized to receive 2% chlorhexidine gluconate in 70% isopropyl alcohol. In patients with open fractures, the risk of infection was similar between the two different antiseptic skin preparation solutions.

These results suggest that the use of iodine povacrylex in alcohol as preoperative skin antisepsis could prevent surgical-site infection in thousands of patients with closed fractures each year.

Skin Antisepsis before Surgical Fixation of Extremity Fractures, New England Journal of Medicine (2024). DOI: 10.1056/NEJMoa2307679

Trees struggle to 'breathe' as climate warms, researchers find

Trees are struggling to sequester heat-trapping carbon dioxide (CO₂) in warmer, drier climates, meaning that they may no longer serve as a solution for offsetting humanity's carbon footprint as the planet continues to warm, according to a new study by researchers.

They  found that trees in warmer, drier climates are essentially coughing instead of breathing. They are sending CO₂ right back into the atmosphere far more than trees in cooler, wetter conditions.

Through the process of photosynthesis, trees remove CO₂ from the atmosphere to produce new growth. Yet, under stressful conditions, trees release CO₂ back to the atmosphere, a process called photorespiration. With an analysis of a global dataset of tree tissue, the research team demonstrated that the rate of photorespiration is up to two times higher in warmer climates, especially when water is limited.

They found the threshold for this response in subtropical climates begins to be crossed when average daytime temperatures exceed roughly 68 degrees Fahrenheit and worsens as temperatures rise further.

The results complicate a widespread belief about the role of plants in helping to draw down—or use—carbon from the atmosphere, providing new insight into how plants could adapt to climate change. Importantly, the researchers noted that as the climate warms, their findings demonstrate that plants could be less able to draw CO₂ out of the atmosphere and assimilate the carbon necessary to help the planet cool down.

Max K. Lloyd et al, Isotopic clumping in wood as a proxy for photorespiration in trees, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2306736120

Out of Rhythm
The occurrence of atrial fibrillation quadrupled over the past 50 years, according to recent studies. A-fib occurs when electrical signals in the upper chambers of the heart—the atria—misfire, causing an irregular heartbeat. People with the condition experience shortness of breath and tiredness. It can result in strokes if left untreated. But up to a quarter of cases go undiagnosed, according to recent research.

Cause and effect: Doctors are more on the lookout for the condition, which is partially responsible for the rising rates. Also people are living longer, and longer life comes with more health complications like heart disease and cancer. Last November leading medical groups issued new guidelines for preventing and treating A-fib, calling on doctors to encourage heart-healthy habits and early, more aggressive efforts to control heart rhythms.

 Some groups, including women and those in underserved communities, can go undiagnosed. “It's a disease that requires monitoring and detection,” says cardiologist Jared Magnani of the University of Pittsburgh. “And then it requires access to medical care, with a partner in making decisions about things like [medication], and finally more advanced therapies and treatment.”

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undiagnosed

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Antimatter Mystery
Scientists are trying to figure out why there is more regular matter than antimatter in the universe. Antimatter is a mirror version of our normal array of particles, except with an opposite electrical charge. When the universe began at the big bang, equal amounts of matter and antimatter should have been created, but that's not what astronomers observe in today’s universe. In a new experiment, researchers searched for a minuscule property of electrons–the electric dipole moment (eEDM)--in hopes of finding evidence for extra particles or fields in the universe that could explain the antimatter mystery.

What they found: The physicists achieved the most precise measurement of the eEDM to date, and they found no evidence that this property exists for electrons. This means that if new fields explaining the matter-antimatter imbalance exist, their contribution to the eEDM may be indirect or occur at slightly higher energies than scientists thought. Future experiments could detect such fields and help physicists figure out the antimatter problem.

What the experts say: “We know there must be some reason out there for the universe of matter we live in to be the way it is—the question is how long it will take us to discover it,” writes Luke Caldwell, physicist at the University College London.
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 that's not what astronomers observe in today’s universe

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What draws the moth to the flame

Nocturnal insects appear drawn to artificial lights because they instinctively twist their backs towards bright objects. The instinct to tilt their backs towards the brightest thing available at night — the sky — allows insects to quickly figure out which way is up. Researchers who tracked insects’ flight patterns with motion-capture cameras found that this even leads the animals to flip upside down and crash into the ground when the light source is underneath them. The researchers suggest reducing upward-facing lights and ground reflections to avoid confusing flying insects at night.

https://www.nature.com/articles/s41467-024-44785-3

ALMA spots the shadow of a molecular outflow from a quasar when the universe was less than 1 billion years old

Theoretical predictions have been confirmed with the discovery of an outflow of molecular gas from a quasar when the universe was less than a billion years old.

A quasar is a compact region powered by a supermassive black hole located in the center of a massive galaxy. They are extremely luminous, with a point-like appearance similar to stars, and are extremely distant from Earth. Owing to their distance and brightness, they provide a peek into conditions of the early universe, when it was less than 1 billion years old.

Researchers have discovered the first evidence of suppression of star formation driven by an outflow of molecular gas in a quasar-host galaxy in the early universe. Their findings, based on observations they made using the Atacama Large Millimeter/submillimeter Array (ALMA), in Chile, were published in The Astrophysical Journal.

Molecular gas is vital to the formation of stars. As the primary fuel of star formation, the ubiquity and high concentrations of molecular gas within a galaxy would lead to a vast number of stars being formed. By ejecting this gas into intergalactic space faster than it could be consumed by star formation, molecular outflows effectively suppress the formation of stars in galaxies that host quasars.

Theoretical work suggests that molecular gas outflows play an important role in the formation and evolution of galaxies from an early age, because they can regulate star formation. Quasars are especially energetic sources, so  scientists expected that they may be able to generate powerful outflows.

The quasar the researchers observed, J2054-0005, has a very high redshift—it and the Earth are apparently moving away from each other very fast.

The findings from this study are the first strong evidence that powerful molecular gas outflows from quasar-host galaxies exist and impact galaxy evolution at the early cosmic age.

Molecular outflow in the reionization-epoch quasar J2054-0005 revealed by OH 119 μm observations, The Astrophysical Journal (2024). DOI: 10.3847/1538-4357/ad0df5

Differences in heart rate variability in pregnant women could be marker for premature delivery

A team of obstetricians, gynecologists and data analysts has found evidence that wrist-based heart rate monitors could predict a premature birth.

In their study, reported on the open-access site PLOS ONE, pregnant volunteers wore WHOOP monitors prior to giving birth.

Previous research has shown that after becoming pregnant, women experience heart rate variability, defined as fluctuations in the amount of time between heartbeats. This variability declines as the pregnancy progresses, around 33 weeks. At that point, variability begins to increase steadily until birth.

For this new study, the research team wondered if the same changes in variability occur with women who experience premature deliveries. To find out, they turned to WHOOP, a maker of strap-on wrist sensors that monitor heart rate, noting that a small study conducted previously with researchers at WHOOP had shown that the device could be used to track heart rate variability in pregnant women.

In the new study, 241 pregnant women of various nationalities living in 15 countries agreed to wear the device in the months leading up to their delivery. The researchers found that heart rate variability for the women who delivered on or near their due date corresponded with previous findings—variability declined until approximately seven weeks before delivery. But things were markedly different for those women who delivered early—variability patterns were much less consistent. And variability also began a steady increase approximately seven weeks before delivery, which, in their cases, was well before their due dates.

The research team suggests that heart rate monitoring devices could become a new tool for use by obstetricians in monitoring their patients. Such devices, they note, may not only allow for better prediction of delivery dates, but could also help in employing therapies designed to prolong at-risk pregnancies.

Summer R. Jasinski et al, Wearable-derived maternal heart rate variability as a novel digital biomarker of preterm birth, PLOS ONE (2024). DOI: 10.1371/journal.pone.0295899

Parrots can move along thin branches using ‘beakiation’

The sidestep involves shuffling across the underside of a branch using both feet and the beak

To move along narrow branches, a parrot can hang from a branch with its beak, swing its body sideways and grab hold farther along with its feet. The newly described gait, dubbed beakiation, expands the birds’ locomotive repertoire and underscores how versatile their beaks are, researchers report January 31 in Royal Society Open Science.

Parrots “are specialized for climbing and moving around in the trees". What would happen if you flip a bird upside down or make them go onto the tiniest branch possible?

Scientists put four rosy-faced lovebirds (Agapornis roseicollis) to the test. Birds placed on a suspended bar just 2.5 millimeters in diameter realized that the best way to shuffle along it was to use their beaks and feet in a cyclical side-swinging motion. The birds traveled 10 centimeters per second on average during each stride (beak touchdown to beak touchdown).

Watch a parrot “beakiate” along a bar

https://royalsocietypublishing.org/doi/10.1098/rsos.231397

Herbivorous animals can be fooled to leave the plants alone 

 Researchers have shown it is possible to shield plants from the hungry maws of herbivorous mammals by fooling them with the smell of a variety they typically avoid.

Findings from the study published in Nature Ecology & Evolution show tree seedlings planted next to the decoy smell solution were 20 times less likely to be eaten by animals.

This is equivalent to the seedlings being surrounded by actual plants that are unpalatable to the herbivore. In most cases it does trick the animals into leaving the plants alone.

Herbivores cause significant damage to valuable plants in ecological and economically sensitive areas worldwide, but killing the animals to protect the plants can be unethical.

So, researchers  created artificial odors that mimicked the smell of plant species they naturally avoid, and this gently nudged problematic herbivores away from areas we didn't want them to be. Given that many herbivores use plant odor as their primary sense to forage, this method provides a new approach that could be used to help protect valued plants globally, either in conservation or protecting agricultural crops.

The researchers selected an unpalatable shrub in the citrus family, Boronia pinnata, and a palatable canopy species, Eucalyptus punctata, to test the concept.

The study compared using B. pinnata solution and the real plant and found both were equally successful at protecting eucalypt seedlings from being eaten by wallabies.

Olfactory misinformation provides refuge to palatable plants from mammalian browsing, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02330-x

Autoimmune disease link to X chromosome
A molecular coating found on the X chromosome might be one of the reasons women account for around 80% of all cases of autoimmune disease, a category that includes conditions such as lupus and rheumatoid arthritis. In most mammals, including humans, a male’s cells typically include one copy of the X chromosome, whereas a female’s cells typically carry two. Half of women’s X chromosomes are coated with RNA and proteins that muzzle the genes inside — and are targeted by misguided immune molecules. Experiments in male mice with a lupus-like disease showed that those with a form of this coating had higher autoantibody levels and more extensive tissue damage.

https://www.cell.com/cell/fulltext/S0092-8674(24)00002-3?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867424000023%3Fshowall%3Dtrue

Doing science is the ultimate act of rebellion

For women in science it is partly about shattering stereotypes and glass ceilings.

For everybody in science, it is about shattering myths, superstitions, ancient way of thinking, unproven and baseless beliefs, irrationality and everything else an evolved human mind shouldn't be doing.

WHO Warns Cancer Cases Will Jump 77% by 2050. Here's Why.

The number of new cancer cases will rise to more than 35 million in 2050 – 77 percent higher than the figure in 2022, the World Health Organization's cancer agency warned recently.

The WHO's International Agency for Research on Cancer (IARC) cited tobacco, alcohol, obesity and air pollution as key factors in the estimated rise.
"Over 35 million new cancer cases are predicted in 2050", a statement said, a 77-percent increase from the some 20 million cases diagnosed in 2022.

"The rapidly-growing global cancer burden reflects both population ageing and growth, as well as changes to people's exposure to risk factors, several of which are associated with socioeconomic development.

"Tobacco, alcohol and obesity are key factors behind the increasing incidence of cancer, with air pollution still a key driver of environmental risk factors."

The most-developed countries are expected to record the greatest increases in case numbers, with an additional 4.8 million new cases predicted in 2050 compared with 2022 estimates, the WHO said.

The reason insects circle lights at night: They lose track of the sky

It's an observation as old as humans gathering around campfires: Light at night can draw an erratically circling crowd of insects. In art, music and literature, this spectacle is an enduring metaphor for dangerous but irresistible attractions. And watching their frenetic movements really gives the sense that something is wrong—that instead of finding food and evading predators, these nocturnal pilots are trapped by a light.

Sadly, centuries of witnessing what happens have produced little certainty about why it happens. How does a simple light change fast, precise navigators into helpless, flittering captives? We are researchers examining flight, vision and evolution, and we have used high-speed tracking techniques in research published in Nature Communications to provide an answer.

Samuel T. Fabian et al, Why flying insects gather at artificial light, Nature Communications (2024). DOI: 10.1038/s41467-024-44785-3

https://theconversation.com/the-surprising-reason-why-insects-circl...

The reason insects fly around light

Alzheimer's may have once spread from person to person, but the risk of that happening today is incredibly low

An article published this week in the journal Nature Medicine documents what is believed to be the first evidence that Alzheimer's disease can be transmitted from person to person.

The finding arose from long-term follow up of patients who received human growth hormone (hGH) that was taken from brain tissue of deceased donors. Preparations of donated hGH were used in medicine to treat a variety of conditions from 1959 onwards.

The practice stopped in 1985 when it was discovered around 200 patients worldwide who had received these donations went on to develop Creuztfeldt-Jakob disease (CJD), which causes a rapidly progressive dementia. This is an otherwise extremely rare condition, affecting roughly one person in a million.

CJD is caused by prions: infective particles that are neither bacterial or viral, but consist of abnormally folded proteins that can be transmitted from cell to cell. Other prion diseases include kuru, a dementia seen in New Guinea tribespeople caused by eating human tissue, scrapie (a disease of sheep) and variant CJD or bovine spongiform encephalopathy, otherwise known as mad cow disease. This raised public health concerns over the eating of beef products in the United Kingdom in the 1980s.

Human growth hormone (hGH) is produced in the brain by the pituitary gland. Treatments were originally prepared from purified human pituitary tissue. But because the amount of hGH contained in a single gland is extremely small, any single dose given to any one patient could contain material from around 16,000 donated glands. An average course of hGH treatment lasts around four years, so the chances of receiving contaminated material—even for a very rare condition such as CJD—became quite high for such people. hGH is now manufactured synthetically in a laboratory, rather than from human tissue. So this particular mode of CJD transmission is no longer a risk.

Gargi Banerjee et al, Iatrogenic Alzheimer's disease in recipients of cadaveric pituitary-derived growth hormone, Nature Medicine (2024). DOI: 10.1038/s41591-023-02729-2

Study finds new treatment to reverse inflammation and arterial blockages in rheumatoid arthritis

Researchers  have found that the molecule RvT4 enhances the body's natural defenses against atherosclerosis (hardening of the arteries) in patients with rheumatoid arthritis.

Studies in mice undertaken by researchers  show that increasing levels of the RvT4 molecule in the body improves the ability of the body's own defense mechanisms (macrophages) to reduce local inflammation and remove blockages in blood vessels. This breakthrough in understanding the processes involved could lead to better treatments for people who have rheumatoid arthritis (RA), and who are at higher risk of developing cardiovascular disease.

Alongside the more widely-known symptoms of joint inflammation, people with the condition are also twice as likely as others to develop blood vessel disease. This can lead to serious complications and an increased risk of premature death.

One type of blood vessel disease seen in people with RA is atherosclerosis, which is caused by a build-up of fatty material called 'plaque' along the artery walls. This build-up causes the arteries to harden and narrow, making it more difficult to circulate blood around the body. These blockages can also break free, causing heart attacks and strokes. Understanding the reasons why RA patients are at increased risk of these cardiovascular problems is critical in developing better treatments for this group and others.

To gain a better understanding of the causes of blood vessel disease in patients with RA, researchers explored the role of a group of molecules called 13-series resolvins (RvTs). In experimental arthritis the levels of one of these molecules, RvT4, are markedly reduced, a phenomenon that associates with a higher degree of blood vessel disease. This study was designed to explore why this might be the case.

Published in Nature Communications, the study found that treating arthritic mice with RvT4 reduced blood vessel inflammation by re-programming macrophages—a group of white blood cells that accumulate in the diseased vessels—to release stored lipids.

Researchers observed that these lipids were preventing the macrophage from carrying out their usual work of clearing dead cells and reducing localized inflammation in blood vessels. Once freed of their lipid burden, the macrophages were able to move and work much more effectively to reduce the causes of atherosclerosis. The observation that RvT4 restores protective macrophage biological activities is an exciting finding.

Resolvin T4 enhances macrophage cholesterol efflux to reduce vascular disease, Nature Communications (2024). DOI: 10.1038/s41467-024-44868-1

Amazing things can happen with science and technology: AI reads ancient scroll burnt and  buried by Vesuvius eruption!

Healthy living builds 'cognitive reserve' in brain that may prevent dementia

New research suggests healthy lifestyles can help stave off dementia, perhaps by building a resilient 'cognitive reserve' in the aging brain.

The study was based on the brain autopsies on 586 people who lived to an average age of almost 91. Researchers compared each person's lifestyle and end-of-life mental skills to their neurological signs of dementia, such as brain protein plaques or changes in brain blood flow.

None of these brain factors seemed to greatly affect the positive connection between healthy living and a person's end-of-live mental skills.

That means that good nutrition, regular exercise and other factors may instead "provide a cognitive reserve" that buffers against negative changes going on within the brain—allowing older folk to "maintain cognitive abilities" over time, the researchers said.

You can almost sort of cheat the biology a little bit and still not get the symptomatology as early.

There's more on the interplay between lifestyle and brain health at the U.S. Center for Disease Control and Prevention.

Klodian Dhana et al, Healthy Lifestyle and Cognition in Older Adults With Common Neuropathologies of Dementia, JAMA Neurology (2024). DOI: 10.1001/jamaneurol.2023.5491

Looking into the possibility of volcanic lightning being the spark that ignited life on Earth

An international team of geologists, Earth scientists and mineralogists has found evidence suggesting that volcanic lightning may have fixed huge amounts of atmospheric nitrogen, allowing life on Earth to get its start.

In their study, published in the Proceedings of the National Academy of Sciences, the group collected and analyzed ancient volcanic deposits to learn more about how ancient eruptions may have produced nitrates that could have been used to create amino acids.

Prior research has shown that the development of life required fixing nitrogen, a key component of amino acids, during Earth's early years. In modern times, there is plenty of nitrogen in the atmosphere but plants cannot use it directly; it must first be fixed by bacteria that can convert it to nitrates or other nitrogen compounds.

That raises the question of how bacteria and then other life forms originated. In this new study, the researchers found evidence that nitrogen in the atmosphere could have been fixed by volcanic lightning interacting with ash.

Prior research has shown that lightning, whether due to thunderstorms or volcanic eruptions, can lead to the formation of nitrates under the right conditions. Lighting from thunderstorms has been ruled out as a candidate for production of the nitrates that led to the beginning of life due to the limited amounts that are produced.

To find out if the same held true for lightning produced during volcanic eruptions, the research team ventured to sites in Turkey, Italy and Peru, known to host ancient volcanic deposits. Samples from these sites contained large amounts of nitrates. Testing showed that they were atmospheric and had not come directly from the volcano—that left lightning as their likely source. But the thing that truly bolstered their theory was the huge amounts of nitrates they found, which were more than enough to serve as a source for creating amino acids.
The team notes that prior research efforts have led to theories that life began near volcanoes—and one team even found some evidence that suggested volcanic lightning interacting with volcanic gases could produce molecules used by living things, such as amino acids.

Adeline Aroskay et al, Geological evidence of extensive N-fixation by volcanic lightning during very large explosive eruptions, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2309131121

Sperm caught breaking Newton's third law of motion

Some biological cells swim freely in a way that apparently breaks one of Newton’s laws of motion – but only if they have strange elastic properties

HUMAN sperm cells and some microorganisms swim by deforming their bodies in a way that breaks Isaac Newton's third law of motion - and we are closer to understanding how they do it. The findings could inspire tiny swimming robots that also violate this law.

he laws of physics have been broken (or appear to have been broken) by all manner of things, from balancing rocks to Seinfeld’s apartment, and now, by human sperm. The latest law-breakers defy Newton's third law of motion, distorting their bodies as they swim in a way that elicits no response from their surroundings.

Newton's third law states that when one object exerts a force on a second object, the second object exerts an equal and opposite force back. In other words, “for every action, there is an equal and opposite reaction”. However, for biological swimmers such as sperm, this may not be the case.

In a new study, scientists analyzed Chlamydomonas algae and data on human sperm cells, identifying non-reciprocal mechanical interactions, which they call “odd elasticity”, that go against Newton’s third law.

Both Chlamydomonas and sperm cells use hair-like appendages called flagella to move around. These protrude from the cell, almost like a tail, helping to propel it forward by changing shape as they interact with the surrounding fluid. They do so in a non-reciprocal way, meaning they don’t provoke an equal and opposite response from their surroundings and therefore, flout Newton’s third law.

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However, the elasticity of the flagellum doesn’t fully explain how the cell is able to move, which is where odd elasticity comes in. This allows the cells to wiggle their flagella without expending much energy to their surroundings, which would otherwise suppress their motility. 

The higher a cell’s odd elasticity score (or odd elastic modulus), the more able a flagellum is to wave sans large energy loss, and so the cell is better able to move forward – in a way that defies physics.

Sperm and algae are not the only cells in possession of a flagellum – many microorganisms have one (they can make bacteria sound like they’re playing tiny drums)  – which means there are likely other rule-breakers out there to be discovered. Being able to understand and classify other cells or organisms capable of non-reciprocal movement could be very useful, the team behind the study told New Scientist.

Their approach could even help in the design of small elastic robots with the ability to break Newton’s third law, according to one of the study's authors, Kenta Ishimoto of Kyoto University in Japan.

Moreover, the odd elastic modulus can be calculated for any closed-loop system, meaning it could be applied to a wide range of biological data, including active elastic membranes and bulk dynamics, the authors explain in their conclusion.

Breaking the law has never been so beneficial.

The study is published in PRX Life.

https://journals.aps.org/prxlife/abstract/10.1103/PRXLife.1.023002

https://www.iflscience.com/sperm-caught-breaking-the-law-newtons-th...

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Scientists Transformed Pure Water Into a Metal

Water found in nature conducts electricity – but that's because of the impurities therein, which dissolve into free ions that allow an electric current to flow. Pure water only becomes "metallic" – electronically conductive – at extremely high pressures, beyond our current abilities to produce in a lab.

But, as researchers demonstrated for the first time back in 2021, it's not only high pressures that can induce this metallicity in pure water.

By bringing pure water into contact with an electron-sharing alkali metal – in this case an alloy of sodium and potassium – free-moving charged particles can be added, turning water metallic.

The resulting conductivity only lasts a few seconds, but it's a significant step towards being able to understand this phase of water by studying it directly.

You can see the phase transition to metallic water with the naked eye! The silvery sodium-potassium droplet covers itself with a golden glow, which is very impressive.

Metallic water prepared for first time under terrestrial conditions

The idea is that if you squeeze the atoms together tightly enough, the orbitals of the outer electrons would start to overlap, allowing them to move around. For water, this pressure is around 48 megabars – just under 48 million times Earth's atmospheric pressure at sea level.

These substances release their outer electrons very easily, which means they could induce the electron-sharing properties of highly pressurized pure water without the high pressures.

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