New study provides novel insights into the cosmic evolution of amino acids

Scientists perform computational simulations for biological molecules detected in meteorites to clarify the origin of life on Earth.

All biological amino acids on Earth appear exclusively in their left-handed form, but the reason underlying this observation is elusive. Recently, scientists from Japan uncovered new clues about the cosmic origin of this asymmetry. Based on the optical properties of amino acids found on the Murchison meteorite, they conducted physics-based simulations, revealing that the precursors to the biological amino acids may have determined the amino acid chirality during the early phase of galactic evolution.

If you look at your hands, you will notice that they are mirror images of each other. However, no matter how hard you try to flip and rotate one hand, you will never be able to superimpose it perfectly over the other. Many molecules have a similar property called "chirality," which means that the "left-handed" (L) version of a molecule cannot be superimposed onto its "right-handed" (D) mirror image version. Even though both versions of a chiral molecule, called "enantiomers," have the same chemical formula, the way they interact with other molecules, especially with other chiral molecules, can vary immensely.

Interestingly, one of the many mysteries surrounding the origin of life as we know it has to do with chirality. It turns out that biological amino acids (AAs) -- the building blocks of proteins -- on Earth appear only in one of their two possible enantiomeric forms, namely the L-form. However, if you synthesize AAs artificially, both L and D forms are produced in equal amounts. This suggests that, at some early point in the past, L-AAs must have come to dominate a hetero-chiral world. This phenomenon is known as "chiral symmetry breaking."

Against this backdrop, a research team led by Assistant Professor Mitsuo Shoji from University of Tsukuba, Japan, conducted a study aimed at solving this mystery. As explained in their paper published in The Journal of Physical Chemistry Letters, the team sought to find evidence supporting the cosmic origin of the homochirality of AAs on Earth, as well as iron out some inconsistencies and contradictions in our previous understanding.

"The idea that homochirality may have originated in space was suggested after AAs were found in the Murchison meteorite that fell in Australia in 1969," explains Dr. Shoji. Curiously enough, in the samples obtained from this meteorite, each of the L-enantiomers was more prevalent than its D-enantiomer counterpart. One popular explanation for this suggests that the asymmetry was induced by ultraviolet circularly polarized light (CPL) in the star-forming regions of our galaxy. Scientists verified that this type of radiation can, indeed, induce asymmetric photochemical reactions that, given enough time, would favor the production of L-AAs over D-AAs. However, the absorption properties of the AA isovaline are opposite to those of the other AAs, meaning that the UV-based explanation alone is either insufficient or incorrect.

Against this backdrop, Dr. Shoji's team pursued an alternate hypothesis. Instead of far-UV radiation, they hypothesized that the chiral asymmetry was, in fact, induced specifically by the CP Lyman-α (Lyα) emission line, a spectral line of hydrogen atom that permeated the early Milky Way. Moreover, instead of focusing only on photoreactions in AAs, the researchers investigated the possibility of the chiral asymmetry starting in the precursors to the AAs, namely amino propanals (APs) and amino nitriles (ANs).

Through quantum mechanical calculations, the team analyzed Lyα-induced reactions for producing AAs along the chemical pathway adopted in Strecker synthesis. They then noted the ratios of L- to D-enantiomers of AAs, APs, and ANs at each step of the process.

The results showed that L-enantiomers of ANs are preferentially formed under right-handed CP (R-CP) Lyα irradiation, with their enantiomeric ratios matching those for the corresponding AAs. "Taken together, our findings suggest that ANs underlie the origin of the homochirality," remarks Dr. Shoji. "More specifically, irradiating AN precursors with R-CP Lyα radiation lead to a higher ratio of L-enantiomers. The subsequent predominance of L-AAs is possible via reactions induced by water molecules and heat."

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River erosion can shape fish evolution

New findings could explain biodiversity hotspots in tectonically quiet regions.

If we could rewind the tape of species evolution around the world and play it forward over hundreds of millions of years to the present day, we would see biodiversity clustering around regions of tectonic turmoil. Tectonically active regions such as the Himalayan and Andean mountains are especially rich in flora and fauna due to their shifting landscapes, which act to divide and diversify species over time.

But biodiversity can also flourish in some geologically quieter regions, where tectonics hasn't shaken up the land for millennia. The Appalachian Mountains are a prime example: The range has not seen much tectonic activity in hundreds of millions of years, and yet the region is a notable hotspot of freshwater biodiversity.

Now, an MIT study identifies a geological process that may shape the diversity of species in tectonically inactive regions. In a paper appearing in Science, the researchers report that river erosion can be a driver of biodiversity in these older, quieter environments.

They make their case in the southern Appalachians, and specifically the Tennessee River Basin, a region known for its huge diversity of freshwater fishes. The team found that as rivers eroded through different rock types in the region, the changing landscape pushed a species of fish known as the greenfin darter into different tributaries of the river network. Over time, these separated populations developed into their own distinct lineages.

The team speculates that erosion likely drove the greenfin darter to diversify. Although the separated populations appear outwardly similar, with the greenfin darter's characteristic green-tinged fins, they differ substantially in their genetic makeup. For now, the separated populations are classified as one single species.

"Give this process of erosion more time, and I think these separate lineages will become different species," says Maya Stokes PhD '21, who carried out part of the work as a graduate student in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS).

The greenfin darter may not be the only species to diversify as a consequence of river erosion. The researchers suspect that erosion may have driven many other species to diversify throughout the basin, and possibly other tectonically inactive regions around the world.

"If we can understand the geologic factors that contribute to biodiversity, we can do a better job of conserving it," says Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric, and Planetary Sciences at MIT.

The study's co-authors include collaborators at Yale University, Colorado State University, the University of Tennessee, the University of Massachusetts at Amherst, and the Tennessee Valley Authority (TVA). Stokes is currently an assistant professor at Florida State University.

Fish in trees

The new study grew out of Stokes' PhD work at MIT, where she and Perron were exploring connections between geomorphology (the study of how landscapes evolve) and biology. They came across work at Yale by Thomas Near, who studies lineages of North American freshwater fishes. Near uses DNA sequence data collected from freshwater fishes across various regions of North America to show how and when certain species evolved and diverged in relation to each other.

Near brought a curious observation to the team: a habitat distribution map of the greenfin darter showing that the fish was found in the Tennessee River Basin -- but only in the southern half. What's more, Near had mitochondrial DNA sequence data showing that the fish's populations appeared to be different in their genetic makeup depending on the tributary in which they were found.

To investigate the reasons for this pattern, Stokes gathered greenfin darter tissue samples from Near's extensive collection at Yale, as well as from the field with help from TVA colleagues. She then analyzed DNA sequences from across the entire genome, and compared the genes of each individual fish to every other fish in the dataset. The team then created a phylogenetic tree of the greenfin darter, based on the genetic similarity between fish.

From this tree, they observed that fish within a tributary were more related to each other than to fish in other tributaries. What's more, fish within neighboring tributaries were more similar to each other than fish from more distant tributaries.

"Our question was, could there have been a geological mechanism that, over time, took this single species, and splintered it into different, genetically distinct groups?" Perron says.

A changing landscape

Stokes and Perron started to observe a "tight correlation" between greenfin darter habitats and the type of rock where they are found. In particular, much of the southern half of the Tennessee River Basin, where the species abounds, is made of metamorphic rock, whereas the northern half consists of sedimentary rock, where the fish are not found.

They also observed that the rivers running through metamorphic rock are steeper and more narrow, which generally creates more turbulence, a characteristic greenfin darters seem to prefer. The team wondered: Could the distribution of greenfin darter habitat have been shaped by a changing landscape of rock type, as rivers eroded into the land over time?

To check this idea, the researchers developed a model to simulate how a landscape evolves as rivers erode through various rock types. They fed the model information about the rock types in the Tennessee River Basin today, then ran the simulation back to see how the same region may have looked millions of years ago, when more metamorphic rock was exposed.

They then ran the model forward and observed how the exposure of metamorphic rock shrank over time. They took special note of where and when connections between tributaries crossed into non-metamorphic rock, blocking fish from passing between those tributaries. They drew up a simple timeline of these blocking events and compared this to the phylogenetic tree of diverging greenfin darters. The two were remarkably similar: The fish seemed to form separate lineages in the same order as when their respective tributaries became separated from the others.

"It means it's plausible that erosion through different rock layers caused isolation between different populations of the greenfin darter and caused lineages to diversify," Stokes says.

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Iron-rich rocks unlock new insights into Earth's planetary history

Visually striking layers of burnt orange, yellow, silver, brown and blue-tinged black are characteristic of banded iron formations, sedimentary rocks that may have prompted some of the largest volcanic eruptions in Earth's history, according to new research from Rice University.

The rocks contain iron oxides that sank to the bottom of oceans long ago, forming dense layers that eventually turned to stone. The study published this week in Nature Geoscience suggests the iron-rich layers could connect ancient changes at Earth's surface -- like the emergence of photosynthetic life -- to planetary processes like volcanism and plate tectonics.

In addition to linking planetary processes that were generally thought to be unconnected, the study could reframe scientists' understanding of Earth's early history and provide insight into processes that could produce habitable exoplanets far from our solar system.

"These rocks tell -- quite literally -- the story of a changing planetary environment," said Duncan Keller, the study's lead author and a postdoctoral researcher in Rice's Department of Earth, Environmental and Planetary Sciences. "They embody a change in the atmospheric and ocean chemistry."

Banded iron formations are chemical sediments precipitated directly from ancient seawater rich in dissolved iron. Metabolic actions of microorganisms, including photosynthesis, are thought to have facilitated the precipitation of the minerals, which formed layer upon layer over time along with chert (microcrystalline silicon dioxide). The largest deposits formed as oxygen accumulated in Earth's atmosphere about 2.5 billion years ago.

"These rocks formed in the ancient oceans, and we know that those oceans were later closed up laterally by plate tectonic processes," Keller explained.

The mantle, though solid, flows like a fluid at about the rate that fingernails grow. Tectonic plates -- continent-sized sections of the crust and uppermost mantle -- are constantly on the move, largely as a result of thermal convection currents in the mantle. Earth's tectonic processes control the life cycles of oceans.

"Just like the Pacific Ocean is being closed today -- it's subducting under Japan and under South America -- ancient ocean basins were destroyed tectonically," he said. "These rocks either had to get pushed up onto continents and be preserved -- and we do see some preserved, that's where the ones we're looking at today come from -- or subducted into the mantle."

Because of their high iron content, banded iron formations are denser than the mantle, which made Keller wonder whether subducted chunks of the formations sank all the way down and settled in the lowest region of the mantle near the top of Earth's core. There, under immense temperature and pressure, they would have undergone profound changes as their minerals took on different structures.

"There's some very interesting work on the properties of iron oxides at those conditions," Keller said. "They can become highly thermally and electrically conductive. Some of them transfer heat as easily as metals do. So it's possible that, once in the lower mantle, these rocks would turn into extremely conductive lumps like hot plates."

Keller and his co-workers posit that regions enriched in subducted iron formations might aid the formation of mantle plumes, rising conduits of hot rock above thermal anomalies in the lower mantle that can produce enormous volcanoes like the ones that formed the Hawaiian Islands. "Underneath Hawaii, seismological data show us a hot conduit of upwelling mantle," Keller said. "Imagine a hot spot on your stove burner. As the water in your pot is boiling, you'll see more bubbles over a column of rising water in that area. Mantle plumes are sort of a giant version of that."

"We looked at the depositional ages of banded iron formations and the ages of large basaltic eruption events called large igneous provinces, and we found that there's a correlation," Keller said. "Many of the igneous events -- which were so massive that the 10 or 15 largest may have been enough to resurface the entire planet -- were preceded by banded iron formation deposition at intervals of roughly 241 million years, give or take 15 million. It's a strong correlation with a mechanism that makes sense."

The study showed that there was a plausible length of time for banded iron formations to first be drawn deep into the lower mantle and to then influence heat flow to drive a plume toward Earth's surface thousands of kilometers above.

In his effort to trace the journey of banded iron formations, Keller crossed disciplinary boundaries and ran into unexpected insights.

"If what's happening in the early oceans, after microorganisms chemically change surface environments, ultimately creates an enormous outpouring of lava somewhere else on Earth 250 million years later, that means these processes are related and 'talking' to each other," Keller said. "It also means it's possible for related processes to have length scales that are far greater than people expected. To be able to infer this, we've had to draw on data from many different fields across mineralogy, geochemistry, geophysics and sedimentology."

Keller hopes the study will spur further research. "I hope this motivates people in the different fields that it touches," he said. "I think it would be really cool if this got people talking to each other in renewed ways about how different parts of the Earth system are connected."

Keller is part of the CLEVER Planets: Cycles of Life-Essential Volatile Elements in Rocky Planets program, an interdisciplinary, multi-institutional group of scientists led by Rajdeep Dasgupta, Rice's W. Maurice Ewing Professor of Earth Systems Science in the Department of Earth, Environmental and Planetary Sciences.

"This is an extremely interdisciplinary collaboration that's looking at how volatile elements that are important for biology -- carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur -- behave in planets, at how planets acquire these elements and the role they play in potentially making planets habitable," Keller said.

"We're using Earth as the best example that we have, but we're trying to figure out what the presence or absence of one or some of these elements might mean for planets more generally," he added.

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Astronomers discover a key planetary system to understand the formation mechanism of the mysterious 'super-Earths'

A study led by researchers of the University of Liège and the CSIC -- using observations from NASA's TESS telescope -- presents the detection of a system of two planets slightly larger than Earth orbiting a cold star in a synchronized dance. Named TOI-2096, the system is located 150 light-years from Earth.

The discovery is the result of a close collaboration between European and American universities and was made possible by the US space mission TESS (Transiting Exoplanet Survey Satellite), which aims to find planets orbiting nearby bright stars. "TESS is conducting an all-sky survey using the transit method, that is, monitoring the stellar brightness of thousands of stars in the search for a slight dimming, which could be caused by a planet passing between the star and the observer. However, despite its power to detect new worlds, the TESS mission needs support from ground-based telescopes to confirm the planetary nature of the detected signals," explains Francisco J. Pozuelos, astrophysicist, first author of the paper, former member of the ExoTIC laboratory at the Univeristy of Liège, and who has now joined the Spanish National Research Council (IAA-CSIC).

The planets TOI-2096 b and TOI-2096 c were observed with an international network of ground-based telescopes, allowing their confirmation and characterization. The majority of the transits were obtained with telescopes of the TRAPPIST and SPECULOOS projects led by the University of Liège. "Making an exhaustive analysis of the data, we found that the two planets were in resonant orbits: for each orbit of the outer planet, the inner planet orbits the star twice," says Mathilde Timmermans, a doctoral student at the ExoTIC lab at ULiège and second author of the scientific paper. Their periods are therefore very close to being a multiple of each other with about 3.12 days for planet b and about 6.38 days for planet c. This is a very particular configuration, and it causes a strong gravitational interaction between the planets. This interaction delays or accelerates the passage of the planets in front of their star and could lead to the measurement of the planetary masses using larger telescopes in the near future."

The researchers behind the discovery estimate that the radius of planet b -- the closest to its star -- is 1.2 times that of Earth, hence the name 'super-Earth'. Its properties could be similar to Earth's: a planet with a mostly rocky composition, possibly surrounded by a thin atmosphere. Similarly, the radius of planet c is 1.9 times the radius of the Earth and 55% that of Neptune, which could place the planet in the category of 'mini-Neptunes', planets composed of a rocky and icy core surrounded by extended hydrogen- or water-rich atmospheres, such as Uranus and Neptune in our Solar System. These sizes are very interesting because the number of planets with a radius between 1.5 and 2.5 Earth radii is smaller than what theoretical models predict, making these planets a rarity. These planets are of crucial importance given their sizes," notes Mathilde Timmermans, "the formation of super-Earths and mini-Neptunes remains a mystery today. There are several formation models trying to explain it, but none fits the observations perfectly. TOI-2096 is the only system found to date that has a super-Earth and a mini-Neptune precisely at the sizes where the models contradict each other. In other words, TOI-2096 may be the system we've been looking for to understand how these planetary systems have formed."

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Helium nuclei research advances our understanding of cosmic ray origin and propagation

The CALorimetric Electron Telescope (CALET), aboard the Kibo's Exposed Facility (EF) of the International Space Station, has been on a mission to measure the flux of cosmic ray particles since 2015. In a new study, an international team of researchers report the results of a direct measurement of the cosmic ray helium spectrum using the data collected by CALET. In contrast to the single power-law that was previously believed to exist, analysis of the flux data collected between 2015 and 2022 reveals that the energy distribution of cosmic ray helium nuclei follows a Double Broken Power Law.

Much of our understanding of the Universe and its mysterious phenomena is based on theoretical interpretations. In order to deepen the understanding of distant objects and energetic phenomena, astronomers are looking at cosmic rays, which are high-energy charged particles composed of protons, electrons, atomic nuclei, and other subatomic particles. Such studies have revealed that cosmic rays contain all the elements known to us in the periodic table, suggesting that these elements originate from stars and high-energy events such as supernovae. Additionally, due to their charged nature, the path of cosmic rays through space is influenced by the magnetic fields of interstellar phenomena and objects.

Detailed observations of cosmic rays can, thus, not only shed light on the origins of these particles but also decode the existence of high-energy objects and phenomena such as supernova remnants, pulsars, and even dark matter. In an effort to better observe high-energy radiations, Japan, Italy, and USA collaboratively established the CALorimetric Electron Telescope (CALET) on the International Space Station in 2015.

In 2018, observations of the cosmic ray proton spectrum from 50 GeV to 10 TeV revealed that the particle flux of protons at high energies was significantly higher than expected. These results deviated from the conventional cosmic ray acceleration and propagation models that assume a "single power-law distribution," wherein the number of particles decrease with increasing energy.

Consequently, in a study published in 2022, the CALET team, including researchers from Waseda University, found cosmic ray protons in the energy range of 50 GeV to 60 TeV to follow a "Double Broken Power Law." This law assumes that the number of high-energy particles initially increase until 10 TeV (known as spectral hardening) and then decrease with an increase in energy (known as spectral softening).

Extending these observations further, the team has now found similar trends of spectral hardening and softening in the cosmic ray helium spectrum captured over a broad range of energy, from 40 GeV to 250 TeV.

The study, published in the journal Physical Review Letters on 27 April, 2023, was led by Associate Professor Kazuyoshi Kobayashi from Waseda University, Japan, along with contributions from Professor Emeritus Shoji Torii, Principal Investigator of the CALET project, also affiliated with Waseda University, and Research Assistant Paolo Brogi from the University of Siena in Italy.

"CALET has successfully observed energy spectral structure of cosmic ray helium, especially spectral hardening starting from around 1.3 TeV, and the tendency of softening starting from around 30 TeV," says Kobayashi.

These observations are based on data collected by CALET aboard the International Space Station (ISS) between 2015 to 2022. Representing the largest energy range to date for cosmic helium nuclei particles, these observations provide additional evidence for deviation of the particle flux from the single power-law model. The researchers noticed that deviation from the expected power-law distribution was more than eight standard deviations away from the mean, indicating a very low probability of this deviation occurring by chance.

Notably, the initial spectral hardening observed in this data suggests that there may be unique sources or mechanisms that are responsible for accelerating and propagating the helium nuclei to high energies. The discovery of these spectral features is also supported by recent observations from the Dark Matter Particle Explorer, and questions our current understanding of the origin and nature of cosmic rays.

"These results would significantly contribute to the understanding of cosmic ray acceleration in the supernova remnant and propagation mechanism," says Torii.

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Global macrogenetic map of marine habitat-forming species

Species known as marine habitat-forming species -- gorgonians, corals, algae, seaweeds, marine phanerogams, etc. -- are organisms that help generate and structure the underwater landscapes. These are natural refuges for other species, and provide biomass and complexity to the seabeds. But these key species in marine ecosystems are currently threatened by climate change and other perturbations derived from human activity. Now, a study published in the journal Global Ecology and Biogeography warns that even in the marine protected areas (MPAs) the genetic diversity of structural species is not protected, although it is essential for the response and adaptation of populations to changes that alter the natural environment.

The study was carried out by Laura Figuerola-Ferrando, Cristina Linares, Ignasi Montero-Serra and Marta Pagès-Escolà, from the Faculty of Biology of the University of Barcelona and the Biodiversity Research Institute of the UB (IRBio); Jean-Baptiste Ledoux and Aldo Barreiro, from the Interdisciplinary Centre of Marine and Environmental Research (CIIMAR) in Portugal, and Joaquim Garrabou, from the Institute of Marine Sciences (ICM-CSIC).

Genetic diversity is also a component of biodiversity

Traditionally, marine biodiversity management and conservation plans have considered factors such as species richness. Genetic diversity -- another major component of biodiversity -- reflects the genetic variation that exists among organisms of the same species and is a determining factor in the adaptive capacity of populations and their survival. Despite its importance, genetic diversity has so far been overlooked in management and conservation plans.

"Genetic diversity plays a key role in enhancing the ability of species, populations and communities to adapt to rapid environmental changes resulting from climate change and thus increase their resilience," says researcher Laura Figuerola-Ferrando, first author of the study.

"However, -- she continues -- so far, the vast majority of marine protected areas are implemented based on the presence of several species and habitats, without considering their genetic diversity. Another example would be the red list of the International Union for Conservation of Nature (IUCN), which does not consider genetic diversity either."

"In recent years, the need to focus conservation efforts on the protection of genetic diversity has been reinforced. Technological progress in the massive development of different techniques to determine genetic diversity (for example, through the use of microsatellites or small DNA fragments), as well as their affordable cost, can help to include genetic diversity in management and conservation plans," says the researcher from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the UB.

From the northwest Atlantic to the Gulf of Guinea

The study applies macrogenetic techniques to identify general genetic patterns of diverse marine species at large spatial scales. The authors have analyzed data from a global database containing genetic diversity information (based on microsatellites) for more than 9,300 populations of 140 species in different marine regions around the globe.

The results outline a reference scenario of genetic patterns in marine habitat-forming species (corals, macroalgae, marine phanerogams, etc.) of potential interest for improving marine life management and conservation plans.

The northwest Atlantic provinces and the Bay of Bengal are the regions where the highest genetic diversity in marine landscape species has been identified. Quite high values (above the global average) have also been identified in the Mediterranean. In contrast, the marine provinces with the lowest values of genetic diversity are the Gulf of Guinea and the southwest Atlantic.

The findings also indicate a positive correlation between genetic diversity and species richness of both animal and plant marine habitat-forming species. However, the paper warns of a worrying result: the Network of Marine Protected Areas (RAMP) in the large oceanic ecoregions does not preserve areas where the genetic diversity of marine habitat-forming species is highest.

"What we have seen is that what is not being protected in MPAs is genetic diversity. In the study, the initial hypothesis was that within these areas there would be greater genetic diversity, but this has not been the case. In fact, we have seen, at a global level, that there are no differences in genetic diversity between inside and outside the MPAs," notes Laura Figuerola-Ferrando, who is doing her doctoral thesis under the supervision of Cristina Linares (UB) and Joaquim Garrabou (ICM-CSIC).

A new pattern of equatorial biodiversity at the poles

The authors have also identified a specific pattern in the distribution of genetic diversity of the marine habitat-forming species that differs from the traditional models known to date. "This is a bimodal latitudinal pattern: it is a complex biogeographic model and it implies that if we model how the genetic diversity of these species varies with latitude, we find two peaks in temperate zones and a small dip in genetic diversity at the equator," notes the ICREA Academia professor Cristina Linares (UB-IRBio), one of the coordinators of the study together with Jean-Baptiste Ledoux (CIIMAR).

This scientific discovery is relevant because until a few decades ago it was considered that the distribution of biodiversity on the planet followed a unimodal pattern, that is, it had maximum values at the equator and decreased towards the poles. "This is not always the case, especially in terms of species diversity in marine ecosystems. For example, in the case of benthic species, this pattern is biomodal rather than unimodal in terms of both species richness and genetic diversity," explains Cristina Linares.

"In our study, the bimodal latitudinal pattern is influenced by taxonomy: in the used model, we found statistically significant differences between animal species (more genetic diversity) and plant species (less genetic diversity). Furthermore, if we explore the latitudinal pattern separating animal and plant species, we can see that a bimodal pattern continues to be observed in animals, but the same cannot be said for plants," adds researcher Jean-Baptiste Ledoux (CIIMAR).

Genetic diversity: improving conservation management plans

The conclusions of the work recall the need to include the genetic diversity of populations in biodiversity management and conservation plans on the planet. "The importance of having genetic diversity in biodiversity management and conservation plans has just been reinforced with the 'Kunming-Montreal Global Biodiversity Framework' within the Convention on Biological Diversity (CBD/COP/15/L25, 2022). In this context, we believe that the baseline on genetic diversity patterns in marine habitat-forming species defined as our work can be very relevant," notes Jean-Baptiste Ledoux.

This study also reveals that the Mediterranean and Atlantic regions are among the most present in the scientific literature used in this work on macrogenetic patterns of deep-sea structural species.

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Research offers clues for potential widespread HIV cure in people

New research from Oregon Health & Science University is helping explain why at least five people have become HIV-free after receiving a stem cell transplant. The study's insights may bring scientists closer to developing what they hope will become a widespread cure for the virus that causes AIDS, which has infected about 38 million people worldwide.

Published today in the journal Immunity, the OHSU-led study describes how two nonhuman primates were cured of the monkey form of HIV after receiving a stem cell transplant. It also reveals that two circumstances must co-exist for a cure to occur and documents the order in which HIV is cleared from the body -- details that can inform efforts to make this cure applicable to more people.

"Five patients have already demonstrated that HIV can be cured," said the study's lead researcher, Jonah Sacha, Ph.D., a professor at OHSU's Oregon National Primate Research Center and Vaccine and Gene Therapy Institute.

"This study is helping us home in on the mechanisms involved in making that cure happen," Sacha continued. "We hope our discoveries will help to make this cure work for anyone, and ideally through a single injection instead of a stem cell transplant."

The first known case of HIV being cured through a stem cell transplant was reported in 2009. A man who was living with HIV was also diagnosed with acute myeloid leukemia, a type of cancer, and underwent a stem cell transplant in Berlin, Germany. Stem cell transplants, which are also called bone marrow transplants, are used to treat some forms of cancer. Known as the Berlin patient, he received donated stem cells from someone with a mutated CCR5 gene, which normally codes for a receptor on the surface of white blood cells that HIV uses to infect new cells. A CCR5 mutation makes it difficult for the virus to infect cells, and can make people resistant to HIV. Since the Berlin patient, four more people have been similarly cured.

This study was conducted with a species of nonhuman primate known as Mauritian cynomolgus macaques, which the research team previously demonstrated can successfully receive stem cell transplants. While all of the study's eight subjects had HIV, four of them underwent a transplant with stem cells from HIV-negative donors, and the other half served as the study's controls and went without transplants.

Of the four that received transplants, two were cured of HIV after successfully being treated for graft-versus-host disease, which is commonly associated with stem cell transplants.

Other researchers have tried to cure nonhuman primates of HIV using similar methods, but this study marks the first time that HIV-cured research animals have survived long term. Both remain alive and HIV-free today, about four years after transplantation. Sacha attributes their survival to exceptional care from Oregon National Primate Research Center veterinarians and the support of two study coauthors, OHSU clinicians who care for people who undergo stem cell transplants: Richard T. Maziarz, M.D., and Gabrielle Meyers, M.D.

"These results highlight the power of linking human clinical studies with pre-clinical macaque experiments to answer questions that would be almost impossible to do otherwise, as well as demonstrate a path forward to curing human disease," said Maziarz, a professor of medicine in the OHSU School of Medicine and medical director of the adult blood and marrow stem cell transplant and cellular therapy programs in the OHSU Knight Cancer Institute.

The how behind the cure

Although Sacha said it was gratifying to confirm stem cell transplantation cured the nonhuman primates, he and his fellow scientists also wanted to understand how it worked. While evaluating samples from the subjects, the scientists determined there were two different, but equally important, ways they beat HIV.

First, the transplanted donor stem cells helped kill the recipients' HIV-infected cells by recognizing them as foreign invaders and attacking them, similar to the process of graft-versus-leukemia that can cure people of cancer.

Second, in the two subjects that were not cured, the virus managed to jump into the transplanted donor cells. A subsequent experiment verified that HIV was able to infect the donor cells while they were attacking HIV. This led the researchers to determine that stopping HIV from using the CCR5 receptor to infect donor cells is also needed for a cure to occur.

The researchers also discovered that HIV was cleared from the subjects' bodies in a series of steps. First, the scientists saw that HIV was no longer detectable in blood circulating in their arms and legs. Next, they couldn't find HIV in lymph nodes, or lumps of immune tissue that contain white blood cells and fight infection. Lymph nodes in the limbs were the first to be HIV-free, followed by lymph nodes in the abdomen.

The step-wise fashion by which the scientists observed HIV being cleared could help physicians as they evaluate the effectiveness of potential HIV cures. For example, clinicians could focus on analyzing blood collected from both peripheral veins and lymph nodes. This knowledge may also help explain why some patients who have received transplants initially have appeared to be cured, but HIV was later detected. Sacha hypothesizes that those patients may have had a small reservoir of HIV in their abdominal lymph nodes that enabled the virus to persist and spread again throughout the body.

Sacha and colleagues continue to study the two nonhuman primates cured of HIV. Next, they plan to dig deeper into their immune responses, including identifying all of the specific immune cells involved and which specific cells or molecules were targeted by the immune system.

This research is supported by the National Institutes of Health (grants AI112433, AI129703, P51 OD011092) and the Foundation for AIDS Research (grant 108832), and the Foundation for AIDS Immune Research. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

In our interest of ensuring the integrity of our research and as part of our commitment to public transparency, OHSU actively regulates, tracks and manages relationships that our researchers may hold with entities outside of OHSU. In regard to this research, Dr. Sacha has a significant financial interest in CytoDyn, a company that may have a commercial interest in the results of this research and technology. Review?details of OHSU's conflict of interest program?to find out more about how we manage these business relationships.

All research involving animal subjects at OHSU must be reviewed and approved by the university's?Institutional Animal Care and Use Committee (IACUC). The IACUC's priority is to ensure the health and safety of animal research subjects. The IACUC also reviews procedures to ensure the health and safety of the people who work with the animals. No live animal work may be conducted at OHSU without IACUC approval.

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Element creation in the lab deepens understanding of surface explosions on neutron stars

Led by Kelly Chipps of the Department of Energy's Oak Ridge National Laboratory, scientists working in the lab have produced a signature nuclear reaction that occurs on the surface of a neutron star gobbling mass from a companion star. Their achievement improves understanding of stellar processes generating diverse nuclear isotopes.

"Neutron stars are really fascinating from the points of view of both nuclear physics and astrophysics," said ORNL nuclear astrophysicist Kelly Chipps, who led a study published in Physical Review Letters. "A deeper understanding of their dynamics may help reveal the cosmic recipes of elements in everything from people to planets."

Chipps heads the Jet Experiments in Nuclear Structure and Astrophysics, or JENSA, which has collaborators from nine institutions in three countries. The team uses a unique gas jet target system, which produces the world's highest-density helium jet for accelerator experiments, to understand nuclear reactions that proceed with the same physics on Earth as in outer space.

The process of nucleosynthesis creates new atomic nuclei. One element can turn into another when protons or neutrons are captured, exchanged or expelled.

A neutron star has an immense gravitational pull that can capture hydrogen and helium from a nearby star. The material amasses on the neutron star surface until it ignites in repeated explosions that create new chemical elements.

Many nuclear reactions powering the explosions remain unstudied. Now, JENSA collaborators have produced one of these signature nuclear reactions in a lab at Michigan State University. It directly constrains the theoretical model typically used to predict element formation and improves understanding of the stellar dynamics that generate isotopes.

Built at ORNL and now at the Facility for Rare Isotope Beams, a DOE Office of Science user facility that MSU operates, the JENSA system provides a target of lightweight gas that is dense, pure and localized within a couple millimeters. JENSA will also provide the primary target for the Separator for Capture Reactions, or SECAR, a detector system at FRIB that allows experimental nuclear astrophysicists to directly measure the reactions that power exploding stars. Co-author Michael Smith of ORNL and Chipps are members of SECAR's project team.

For the current experiment, the scientists struck a target of alpha particles (helium-4 nuclei) with a beam of argon-34. (The number after an isotope indicates its total number of protons and neutrons.) The result of that fusion produced calcium-38 nuclei, which have 20 protons and 18 neutrons. Because those nuclei were excited, they ejected protons and ended up as potassium-37 nuclei.

High-resolution charged-particle detectors surrounding the gas jet precisely measured energies and angles of the proton reaction products. The measurement took advantage of detectors and electronics developed at ORNL under the leadership of nuclear physicist Steven Pain. Accounting for the conservation of energy and momentum, the physicists back-calculated to discover the dynamics of the reaction.

"Not only do we know how many reactions occurred, but also we know the specific energy that the final potassium-37nucleus ended up in, which is one of the components predicted by the theoretical model," Chipps said.

The lab experiment improves understanding of nuclear reactions that occur when material falls onto the surface of an important subset of neutron stars. These stars are born when a massive star runs out of fuel and collapses into a sphere about as wide as a city such as Atlanta, Georgia. Then gravity squeezes fundamental particles as close together as they can get, creating the densest matter we can directly observe. One teaspoon of neutron star would weigh as much as a mountain. Neutron-packed stars rotate faster than blender blades and make the universe's strongest magnets. They have solid crusts surrounding liquid cores containing material shaped like spaghetti or lasagna noodles, earning them the nickname "nuclear pasta."

"Because neutron stars are so weird, they are a useful naturally occurring laboratory to test how neutron matter behaves under extreme conditions," Chipps said.

Achieving that understanding takes teamwork. Astronomers observe the star and collect data. Theoreticians try to understand physics inside the star. Nuclear physicists measure nuclear reactions in the lab and test them against models and simulations. That analysis reduces large uncertainties resulting from a dearth of experimental data. "When you put all of those things together, you really start to understand what's happening," Chipps said.

"Because the neutron star is superdense, its huge gravity can pull hydrogen and helium over from a companion star. As this material falls to the surface, the density and temperature grow so high that a thermonuclear explosion can occur that can propagate across the surface," Chipps said. Thermonuclear runaway transforms nuclei into heavier elements. "The reaction sequence can produce dozens of elements."

Surface explosions do not destroy the neutron star, which goes right back to what it was doing before: feeding off its companion and exploding. Repeated explosions pull crust material into the mix, creating a bizarre composition in which heavy elements formed during previous explosions react with lightweight hydrogen and helium.

Theoretical models predict which elements form. Scientists typically analyze the reaction that the JENSA team measured using a statistical theoretical model called the Hauser-Feshbach formalism, which assumes that a continuum of excited energy levels of a nucleus can participate in a reaction. Other models instead assume that only a single energy level participates.

"We're testing the transition between the statistical model being valid or invalid," Chipps said. "We want to understand where that transition happens. Because Hauser-Feshbach is a statistical formalism -- it relies on having a large number of energy levels so effects over each individual level are averaged out -- we're looking for where that assumption starts to break down. For nuclei like magnesium-22 and argon-34, there's an expectation that the nucleus doesn't have enough levels for this averaging approach to be valid. We wanted to test that."

A question remained about whether the statistical model was valid for such reactions taking place in stars rather than earthly laboratories. "Our result has shown that the statistical model is valid for this particular reaction, and that removes a tremendous uncertainty from our understanding of neutron stars," Chipps said. "It means that we now have a better grasp of how those nuclear reactions are proceeding."

Next, the researchers will try to improve the statistical model by further testing its limits. A past paper explored atomic mass 22, a magnesium nucleus, and found the model incorrect by almost a factor of 10. The current ORNL-led paper, probing 12 atomic mass units above this, found that the model correctly predicted reaction rates.

"Somewhere between [atomic] mass 20 and 30, this transition between where the statistical model is valid and where it's not valid is taking place," Chipps said. "The next thing is to look for reactions in the middle of that range to see where this transition is occurring." Chipps and her JENSA collaborators have begun that endeavor.

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How tasty is the food?

To know when it's time for a meal -- and when to stop eating again -- is important to survive and to stay healthy, for humans and animals alike. Researchers at the Max Planck Institute for Biological Intelligence investigated how the brain regulates feeding behavior in mice. The team found that the hormone ghrelin activates specialized nerve cells in a brain region known as the amygdala. Here, the interaction between ghrelin and the specialized neurons promotes food consumption and conveys hunger and the pleasant and rewarding feelings associated with eating.

Hunger is a powerful sensation with important biological underpinnings. It signals the body to look for food, which is a crucial behavior to prevent starvation and ensure survival. When we're hungry, we crave for food -- and when we finally get to eat, our body rewards us with pleasant feelings and a general state of happiness.

A network of brain circuits and signaling pathways orchestrates the eating behavior of humans and animals and elicits the associated sensations. One of the central players in this network is the hormone ghrelin. It is released by stomach cells when humans and animals are hungry or fasting, and promotes feeding behavior.

The department of Rüdiger Klein at the Max Planck Institute for Biological Intelligence studies the brain networks that underly feeding behavior in mice. To this end, the researchers conducted a thorough analysis of the different cell types in a brain region known as the central amygdala. "Previously, the amygdala had mostly been studied in the context of feelings like fear and reward, while the regulation of feeding was thought to happen in different parts of the brain, such as the hypothalamus," says Christian Peters, a postdoctoral researcher in the department.

Nine cell clusters

Peters and his colleagues analyzed individual cells in the central amygdala, studying messenger RNA molecules -- the cell's working copies of their genes. The analysis revealed that the cells are organized into nine different cell clusters. Some of these clusters promote appetite while others inhibit it, and they adjust their production of messenger RNAs when the mice are fed or fasting.

"We now have a much better understanding of the diversity of cell types and the physiological processes that promote feeding in the central amygdala," says Rüdiger Klein. "Our research uncovers for the first time that the 'hunger hormone' ghrelin also acts on cells in the central amygdala." There, it activates a small subset of cell clusters, collectively marked by the presence of the protein Htr2a, to increase feeding.

Multiple functions for ghrelin

The scientists found that the Htr2a neurons became active after an overnight fast or when stimulated by the hormone ghrelin. The cells also responded when the researchers presented food to the mice. "We think that ghrelin performs multiple functions," explains Christian Peters. "When mice are hungry, ghrelin activates the appetitive brain regions to predispose the animals for eating. In addition, the hormone enhances the activity in brain circuits, such as the amygdala, that confer rewards, which is likely an incentive to eat additional food." This way, ghrelin increases the palatability of food in proportion to how satiated the mice currently are.

After a fasting diet, when the animals were very hungry the activity of Htr2a neurons was not needed to start feeding, presumably because the tastiness of food is less important under these conditions. "Other brain circuits, for example the hypothalamus, which regulate the body's metabolism, take over and signal the mice that it's important to eat in order to survive," says Christian Peters.

Feeling hungry or satiated has profound impacts on physical but also on emotional wellbeing, as probably everyone knows by the pleasures associated with eating tasty food. "The neuronal networks that convey these feelings are obviously linked to those that control eating, yet it is not fully understood how exactly they influence each other," says Rüdiger Klein.

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Move over, armadillos: There's a new bone-plated mammal in town

Mammals are a bit odd when it comes to bones. Rather than the bony plates and scales of crocodiles, turtles, lizards, dinosaurs and fish, mammals long ago traded in their ancestral suit of armor for a layer of insulating hair.

Armadillos, with their protective and flexible shell of imbricated bone, are considered the only living exception. But a new study, published in the journal iScience, unexpectedly shows that African spiny mice produce the same structures beneath the skin of their tails, which until now had gone largely undetected.

The discovery was made during routine CT scanning of museum specimens for the openVertebrate program, an initiative to provide 3D models of vertebrate organisms for researchers, educators and artists.

"I was scanning a mouse specimen from the Yale Peabody Museum, and the tails looked abnormally dark," said co-author Edward Stanley, director of the Florida Museum of Natural History's digital imaging laboratory.

He initially assumed the discoloration was caused by an imperfection introduced during the specimen's preservation. But when he analyzed the X-Rays several days later, Stanley observed an unmistakable feature he was intimately familiar with.

"My entire PhD was focused on osteoderm development in lizards. Once the specimen scans had been processed, the tail was very clearly covered in osteoderms."

Spiny mice osteoderms have been observed at least once before and were noted by German biologist Jochen Niethammer, who compared their architecture to medieval stonework in an article published in 1975. Niethammer correctly interpreted the plates as being a type of bone but never followed up on his initial observations, and the group was largely overlooked for several decades -- until scientists discovered another, seemingly unrelated peculiarity of spiny mice.

A study from 2012 demonstrated spiny mice can completely regenerate injured tissue without scarring, an ability common in reptiles and invertebrates but previously unknown in mammals. Their skin is also particularly fragile, tearing at roughly one-fourth the amount of force required to injure the skin of a common mouse. But spiny mice can heal twice as fast as their relatives.

Researchers hoping to find a model for human tissue regeneration have begun mapping the genetic pathways that give spiny mice their extraordinary powers of healing. One such researcher, Malcolm Maden, just so happened to have a lab in the building across from Stanley's office.

"Spiny mice can regenerate skin, muscle, nerves, spinal cord and perhaps even cardiac tissue, so we maintain a colony of these rare creatures for research," said Maden, a biology professor at the University of Florida and lead author on the study.

Maden and his colleagues analyzed the development of spiny mice osteoderms, confirming they were in fact similar to those of armadillos but had most likely evolved independently. Osteoderms are also distinct from the scales of pangolins or the quills of hedgehogs and porcupines, which are composed of keratin, the same tissue that makes up hair, skin and nails.

There are four genera of spiny mice, which all belong to the subfamily Deomyinae. However, aside from similarities in their DNA and potentially the shape of their teeth, scientists have been unable to find a single feature shared among species of this group that distinguishes them from other rodents.

Stanley, suspecting their differences might only be skin deep, scanned additional museum specimens from all four genera. In each, he found spiny mice tails were covered in the same sheath of bone. The closest relatives of Deomyinae -- gerbils -- lacked osteoderms, meaning the trait had likely evolved just once, in the ancestor of erstwhile disparate spiny mice.

The ubiquity of osteoderms in the group indicate they serve an important protective function. Just what that function might be wasn't immediately apparent, however, due to yet another peculiar attribute of spiny mice: Their tails are uncharacteristically detachable. Tail loss is so common in some spiny mouse species that nearly half the individuals of a given population have been shown to lack them in the wild.

"This was a real head-scratcher," Stanley said. "Spiny mice are famously able to deglove their tails, meaning the outer layer of skin comes off, leaving behind the muscle and bone. Individuals will often chew off the remainder of the tail when this happens."

Despite their powers of regeneration, tail shedding is a trick that spiny mice can only perform once. Unlike some lizards, they can't regrow their tails, and not every part of the tail separates easily.

To find out why rodents that seem ambivalent about keeping their tails would go through the trouble of covering them in armor, the authors turned to a group of similarly odd fish-tale geckos from Madagascar. Most geckos lack osteoderms, but as their name implies, fish-tale geckos are covered in thin, overlapping plates, and just like spiny mice, they have incredibly fragile skin that sheds at the slightest provocation.

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Multivitamin improves memory in older adults, study finds

Taking a daily multivitamin supplement can slow age-related memory decline, finds a large study led by researchers at Columbia University and Brigham and Women's Hospital/Harvard.

"Cognitive aging is a top health concern for older adults, and this study suggests that there may be a simple, inexpensive way to help older adults slow down memory decline," says study leader Adam M. Brickman, PhD, professor of neuropsychology at Columbia University Vagelos College of Physicians and Surgeons.

Many older people take vitamins or dietary supplements under the assumption that they will help maintain general health. But studies that have tested whether they improve memory and brain function have been mixed, and very few large-scale, randomized trials have been done.

Study methods

In the current study, more than 3,500 adults (mostly non-Hispanic white) over age 60 were randomly assigned to take a daily multivitamin supplement or placebo for three years. At the end of each year, participants performed a series of online cognitive assessments at home designed to test memory function of the hippocampus, an area of the brain that is affected by normal aging. The COSMOS-Web study is part of a large clinical trial led by Brigham & Women's Hospital and Harvard called the COcoa Supplement and Multivitamin Outcomes Study (COSMOS).

By the end of the first year, memory improved for people taking a daily multivitamin, compared with those taking a placebo. The researchers estimate the improvement, which was sustained over the three-year study period, was equivalent to about three years of age-related memory decline. The effect was more pronounced in participants with underlying cardiovascular disease.

The results of the new study are consistent with another recent COSMOS study of more than 2,200 older adults that found that taking a daily multivitamin improved overall cognition, memory recall, and attention, effects that were also more pronounced in those with underlying cardiovascular disease.

"There is evidence that people with cardiovascular disease may have lower micronutrient levels that multivitamins may correct, but we don't really know right now why the effect is stronger in this group," says Brickman.

Good nutrition important for aging brain

Though the researchers did not look at whether any specific component of the multivitamin supplement was linked to the improvement in memory, the findings support growing evidence that nutrition is important for optimizing brain health as we age.

"Our study shows that the aging brain may be more sensitive to nutrition than we realized, though it may not be so important to find out which specific nutrient helps slow age-related cognitive decline," says Lok-Kin Yeung, PhD, a postdoctoral researcher in Columbia's Taub Institute for Research on Alzheimer's Disease and the Aging Brain and first author of the study.

"The finding that a daily multivitamin improved memory in two separate cognition studies in the COSMOS randomized trial is remarkable, suggesting that multivitamin supplementation holds promise as a safe, accessible, and affordable approach to protecting cognitive health in older adults," says co-author JoAnn Manson, MD, chief of the Division of Preventive Medicine at Brigham and Women's Hospital.

"Supplementation of any kind shouldn't take the place of more holistic ways of getting the same micronutrients," adds Brickman. "Though multivitamins are generally safe, people should always consult a physician before taking them."

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NASA's Hubble hunts for intermediate-sized black hole close to home

Astronomers using NASA's Hubble Space Telescope have come up with what they say is some of their best evidence yet for the presence of a rare class of "intermediate-sized" black hole that may be lurking in the heart of the closest globular star cluster to Earth, located 6,000 light-years away.

Like intense gravitational potholes in the fabric of space, virtually all black holes seem to come in two sizes: small and humongous. It's estimated that our galaxy is littered with 100 million small black holes (several times the mass of our Sun) created from exploded stars. The universe at large is flooded with supermassive black holes, weighing millions or billions of times our Sun's mass and found in the centers of galaxies.

A long-sought missing link is an intermediate-mass black hole, weighing in somewhere between 100 and 100,000 solar masses. How would they form, where would they hang out, and why do they seem to be so rare?

Astronomers have identified other possible intermediate-mass black holes through a variety of observational techniques. Two of the best candidates -- 3XMM J215022.4−055108, which Hubble helped discover in 2020, and HLX-1, identified in 2009 -- reside in dense star clusters in the outskirts of other galaxies. Each of these possible black holes has the mass of tens of thousands of suns, and may have once been at the centers of dwarf galaxies. NASA's Chandra X-ray observatory has also helped make many possible intermediate black hole discoveries, including a large sample in 2018.

Looking much closer to home, there have been a number of suspected intermediate-mass black holes detected in dense globular star clusters orbiting our Milky Way galaxy. For example, in 2008, Hubble astronomers announced the suspected presence of an intermediate-mass black hole in the globular cluster Omega Centauri. For a number of reasons, including the need for more data, these and other intermediate-mass black hole findings still remain inconclusive and do not rule out alternative theories.

Hubble's unique capabilities have now been used to zero in on the core of the globular star cluster Messier 4 (M4) to go black-hole hunting with higher precision than in previous searches. "You can't do this kind of science without Hubble," said Eduardo Vitral of the Space Telescope Science Institute in Baltimore, Maryland, lead author on a paper to be published in the Monthly Notices of the Royal Astronomical Society.

Vitral's team has detected a possible intermediate-mass black hole of roughly 800 solar masses. The suspected object can't be seen, but its mass is calculated by studying the motion of stars caught in its gravitational field, like bees swarming around a hive. Measuring their motion takes time, and a lot of precision. This is where Hubble accomplishes what no other present-day telescope can do. Astronomers looked at 12 years' worth of M4 observations from Hubble and resolved pinpoint stars.

His team estimates that the black hole in M4 could be as much as 800 times our Sun's mass. Hubble's data tend to rule out alternative theories for this object, such as a compact central cluster of unresolved stellar remnants like neutron stars, or smaller black holes swirling around each other.

"We have good confidence that we have a very tiny region with a lot of concentrated mass. It's about three times smaller than the densest dark mass that we had found before in other globular clusters," said Vitral. "The region is more compact than what we can reproduce with numerical simulations when we take into account a collection of black holes, neutron stars, and white dwarfs segregated at the cluster's center. They are not able to form such a compact concentration of mass."

A grouping of close-knit objects would be dynamically unstable. If the object isn't a single intermediate-mass black hole, it would require an estimated 40 smaller black holes crammed into a space only one-tenth of a light-year across to produce the observed stellar motions. The consequences are that they would merge and/or be ejected in a game of interstellar pinball.

"We measure the motions of stars and their positions, and we apply physical models that try to reproduce these motions. We end up with a measurement of a dark mass extension in the cluster's center," said Vitral. "The closer to the central mass, more randomly the stars are moving. And, the greater the central mass, the faster these stellar velocities."

Because intermediate-mass black holes in globular clusters have been so elusive, Vitral cautions, "While we cannot completely affirm that it is a central point of gravity, we can show that it is very small. It's too tiny for us to be able to explain other than it being a single black hole. Alternatively, there might be a stellar mechanism we simply don't know about, at least within current physics."

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Researchers want to use 'biochar' to combat climate change

A new review of research suggests that the nature-based technology biochar -- a carbon-rich material -- could be an important tool to use in agriculture to help mitigate climate change.

Made by pyrolysis, a process that involves heating organic material in a low-oxygen environment, biochar -- a charcoal-like, porous substance -- has long been utilized for crop production as a soil amendment or carbon sequestration agent. In recent years, researchers have seen a resurgence of heightened interest in the technology due to its unique physical structure and its various agricultural and environmental benefits.

It's for these reasons that biochar's potential to remove large amounts of greenhouse gases from the atmosphere deserves to be re-evaluated, said Raj Shrestha, lead author of the study and a research associate in horticulture and crop science at The Ohio State University.

"When farmers grow their crops, they apply fertilizer and/or manure and use different kinds of machinery to till the soil," said Shrestha. "In the process, greenhouse gases are produced and released into the atmosphere."

But farmers could lessen this impact by applying biochar to their fields, according to the paper, recently published in the Journal of Environmental Quality.

"If we can convince farmers that converting biomass to biochar is good for the long-term sustainability of soils, the economy, and good for the environment, then we'll be able to see wide adoption of this technology," said Shrestha.

The researchers reviewed more than 200 field studies conducted across the globe that examined the impact of biochar application in agriculture on emissions of nitrous oxide, methane and carbon dioxide -- heat-trapping gases that cause Earth's atmosphere to warm.

The team found that the amount of biochar in the soil does have variable effects on local greenhouse gas emissions, which range from a decrease to an increase, and, in some cases, no change. But in general, the team discovered that the use of biochar in field settings lowered the amount of nitrous oxide in the air by about 18% and methane by 3%.

Biochar alone was also not effective at reducing carbon dioxide emissions, but did help when combined with commercial nitrogen fertilizer or other organic materials, like manure or compost.

"We can achieve negative emission in our agroecosystems by reducing the carbon source and enhancing carbon sink," said Shrestha. Reducing Earth's carbon source can be achieved by reducing greenhouse gas emissions from our activities, and enhancing carbon sink -- increasing the technology's ability to absorb more carbon than it releases into the atmosphere -- can be done by increasing the long-term soil carbon pool through conversion of organic waste into biochar, he said.

"What's good about biochar is that it contributes to both these aspects to create net negative agriculture," said Shrestha.

Right now, when farmers leave crop residue on the field, only about 10% to 20% of the residue carbon is recycled into soil during the decomposition process, but by converting the same amount of residue to biochar and then applying it to the field, we can store about 50% of that carbon into stable carbon forms."

As biochar-carbon placed in the soil can also last anywhere from a few hundred to thousands of years, it's currently one of the proposed best management practices for achieving negative emissions and preventing Earth's average temperature from increasing to 1.5 degrees Celsius above pre-industrial levels.

According to the study, between 2011 and 2020, global greenhouse gas emissions rose: carbon dioxide by about 5.6%, methane by 4.2%, and nitrous oxide by 2.7% -- and agriculture accounts for about 16% of these emissions. While such levels have already led to irreversible changes to the global climate system, Shrestha said that future damages could be slowed by helping to curb the extent of emissions from the farming and forestry sectors.

Yet despite biochar's potential as a negative emission technology and the recent increase in biochar-related research, it's difficult to get farmers to apply it, partly because it hasn't been commercialized for widespread use or promoted well, said Shrestha.

To better deliver more science-based, practical information about the technology and its benefits to farmers and agriculture-related businesses, many lawmakers have enacted policies meant to investigate its effectiveness across many different soil types and environmental conditions. It's an objective that Shrestha shares, as the main goal of his team's review paper is to improve farmers' confidence in biochar so that more of them choose to adopt it sooner.

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Humans are unique but not exceptional species of mammal

In modern society, one parent may take a daughter to ballet class and fix dinner so the other parent can get to exercise class before picking up the son from soccer practice. To an observer, they seem to be cooperating in their very busy, co-parenting, monogamous relationship.

These people may think they are part of an evolved society different from the other mammals that inhabit earth. But their day-to-day behavior and child-rearing habits are not much different than other mammals who hunt, forage for food, and rear and teach their children, researchers suggest.

"For a long time it has been argued that humans are an exceptional, egalitarian species compared to other mammals," said Monique Borgerhoff Mulder, professor emerita of anthropology at the University of California, Davis, and corresponding author of a new study. But, she said, this exceptionalism may have been exaggerated.

"Humans appear to resemble mammals that live in monogamous partnerships and to some extent, those classified as cooperative breeders, where breeding individuals have to rely on the help of others to raise their offspring," she said.

The UC Davis-led study, with more than 100 researchers collaborating from several institutions throughout the world, is the first to look at whether human males are more egalitarian than are males among other mammals, focusing on the numbers of offspring they produce.

The article, "Reproductive inequality in humans and other mammals," was published this week (May 22) in the Proceedings of the National Academy of Sciences. Co-authors include researchers from UC Davis, The Santa Fe Institute, the National Institute for Mathematical and Biological Synthesis, and the Max Planck Institute for Evolutionary Anthropology, Germany.

The researchers amassed data from 90 human populations comprising 80,223 individuals from many parts of the world -- both historical and contemporary. They compared the records for men and women to lifetime data for 45 different nonhuman, free-ranging mammals.

The researchers found that humans are by no means exceptional, merely another unique species of mammal. Furthermore, as first author Cody Ross, former UC Davis graduate student in the Department of Anthropology now at the Max Planck Institute, points out "we can quite successfully model reproductive inequality in humans and nonhumans using the same predictors."

Egalitarianism in polygynous societies

Somewhat unexpectedly, when focusing specifically on women, the researchers found greater reproductive egalitarianism in societies that allow for polygynous marriage than in those where monogamous marriage prevails. In polygynous systems, in which men take several wives at the same time, women tend to have more equal access to resources, such as land, food and shelter -- and parenting help. This is because women, or their parents on their behalf, favor polygynous marriages with wealthy men who have more resources to share.

Researchers observed something else in their work.

"It turns out that monogamous mating (and marriage) can drive significant inequalities among women," Borgerhoff Mulder said. Monogamy, practiced in agricultural and market economies, can promote large differences in the number of children couples produce, researchers found, resulting from large differences in wealth in such economies.

How humans may differ

The fact men are relatively egalitarian compared to other animals reflects our patterns of child rearing. Human children are heavily dependent on the care and resources provided by both mothers and fathers -- a factor that is unusual, but not completely absent -- in other mammals, researchers said.

The critical importance of the complementary nature of this care -- that that each parent provides different and often non-substitutable resources and care throughout long human childhoods -- is why we don't show the huge reproductive variability seen in some of the great apes, said researcher Paul Hooper, from the University of New Mexico.

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Extinct offshore volcano could store gigatons of carbon dioxide

A new study published in Geology concludes that an extinct volcano off the shore of Portugal could store as much as 1.2-8.6 gigatons of carbon dioxide, the equivalent of ~24-125 years of the country's industrial emissions. For context, in 2022 a total of 42.6 megatons (0.0426 gigatons) of carbon dioxide was removed from the atmosphere by international carbon capture and storage efforts, according to the Global CCS Institute. The new study suggests that carbon capture and storage in offshore underwater volcanoes could be a promising new direction for removal and storage of much larger volumes of the greenhouse gas from the atmosphere.

"We know that most countries, including Portugal, are making efforts to decarbonize the economy and our human activities, this is a message that this may be one of the instruments to solve the problem" says Ricardo Pereira, a geologist at the NOVA School of Science and Technology, and co-author of the study.

Storing carbon dioxide in an extinct volcano would rely on a process known as 'in situ mineral carbonation.' In this process, carbon dioxide reacts with elements in certain types of rocks to produce new minerals that safely and permanently store the carbon dioxide. Elements like calcium, magnesium, and iron combine with carbon dioxide to form the minerals calcite, dolomite, and magnesite, respectively. Rocks that contain large amounts of calcium, iron, and magnesium are ideal candidates for this process -- such as the volcanic basalts that make up most of the sea floor. Knowing this, the researchers targeted an offshore volcano for a few reasons -- the structure of the volcano could provide an ideal architecture for carbon injection and storage, the rocks are the right type for the reactions involved, and the location Is not too close to large populations, but also not too far.

Most carbon capture projects have relied on injection of carbon dioxide into porous sedimentary basins that are sealed to prevent migration of the gas out of reservoirs. In these cases, the carbon will eventually start to form minerals, but only over longer periods of time -- decades to centuries. In 2016, researchers published findings that 95% of carbon dioxide injected into underground basalts in Iceland had mineralized within just two years. The much shorter mineralization time makes the process safer and more effective -- once carbon is stored in minerals, issues like potential leaks are no longer a concern.

Davide Gamboa, a geologist at the University of Aveiro and co-author of the study, explains, "What makes mineral carbonation really interesting is the time. The faster it gets into a mineral, the safer it becomes, and once it's a mineral, it is permanent."

The researchers studied the storage potential at the ancient Fontanelas volcano, which is partially buried ~100 kilometers offshore from Lisbon, with a peak ~1500 meters below sea-level.

To estimate the potential volume of carbon dioxide that could be stored at this site, the authors used 2D and 3D seismic studies of the undersea volcano that had been produced during offshore oil exploration, as well as data from samples that had been dredged from the area in 2008. The dredged samples contained naturally formed carbonate minerals, indicating that the chemical reactions required to store carbon were already happening, and that intentional efforts to mineralize carbon in these rocks should be successful. The samples also had up to 40% pore space -- meaning there are spaces within the rocks where carbon dioxide could be injected and mineralized. The researchers also indicate that low-permeability layers imaged around the flanks of the volcano could help with containing the carbon dioxide before it is mineralized.

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A deep underground lab could hold key to habitability on Mars

Tunnels deep underground in North Yorkshire are providing a unique opportunity to study how humans might be able to live and operate on the Moon or on Mars.

Researchers at the University of Birmingham have launched the Bio-SPHERE project in a unique research facility located 1.1 km below the surface, in one of the deepest mine sites in the UK. The project investigates how scientific and medical operations would take place in the challenging environments of the Moon and Mars.

It is the first of a series of new laboratory facilities planned to study how humans might work -- and stay healthy -- during long space missions, a key requirement for ensuring mission continuity on other planets.

The team is working in partnership with the Boulby Underground Laboratory, a 4,000m3 deep underground facility focused on particle physics, Earth sciences and astrobiology research, run by the Science and Technology Facilities Council (part of UK Research and Innovation) with the support of the Boulby Mine operators, ICL-UK.

The Bio-SPHERE project is based in a 3,000m3 tunnel network adjacent to the Boulby Laboratory, which go through 250-million-year-old rock salt deposits, consisting of Permian evaporite layers left over from the Zechstein Sea. This geological environment, together with the deep subsurface location, have enabled researchers to recreate the operational conditions humans would experience working in similar caverns on the Moon and Mars. This includes remoteness, limited access to new materials and challenges in moving heavy equipment around.

At the same time, thanks to the ultra-low radiation environment provided by that depth, the location will enable scientists to investigate how effective underground habitats might be in protecting space crews from deep-space radiation, which is a significant risk in space exploration, as well as other hazards, such as falling debris from meteorites, which risks damaging the life-support infrastructure.

The first facility to be opened as part of Bio-SPHERE (Biomedical Sub-surface Pod for Habitability and Extreme-environments Research in Expeditions), is based in a 3-metre-wide simulation module and is designed specifically to test biomedical procedures needed to prepare materials for treating tissue damage. These include complex fluids, polymers and hydrogels for regenerative medicine that could be used, for example, in wound dressings, or fillers for damage mitigation.

A paper describing the concept and design of such a habitat was recently published in Nature (NPJ) Microgravity.

Bio-SPHERE, which includes a range of capabilities for sterile work and material processing, combines these simulation facilities and useful geological environment with access to the adjacent physics and chemistry laboratory facilities.

This environment provides the opportunity to simulate various mission scenarios and to conduct cutting edge, interdisciplinary science, ranging from the effects of extreme environments on biological and physicochemical parameters and on medical infrastructure, all the way to investigating how available 'in-situ' resources such as ambient pressure, temperature and geology can be used for habitat construction.

Lead researcher Dr Alexandra Iordachescu, in the University of Birmingham's School of Chemical Engineering, said: "We are excited to be partnering with the fantastic science team at the Boulby Underground Laboratory. This new capability will help to gather information that can advise on the life support systems, devices and biomaterials which could be used in medical emergencies and tissue repair following damage in deep-space missions.

"These types of metrics can guide system design and help to assess the scientific needs and acceptable timeframes in bioengineering operations under the constraints of isolated environments, such as space habitats. The data is likely to bring numerous benefits for Earth-based applications as well, such as delivering biomedical interventions in remote areas or in hazardous environments and more generally, understanding biomedical workflows in these non-ideal environments."

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Montreal protocol is delaying first ice-free Arctic summer

When scientists discovered a hole over Antarctica in 1985, countries across the globe got together and wrote a treaty designed to protect the ozone layer, which shields the Earth -- and us -- from harmful levels of ultraviolet radiation. The resulting Montreal Protocol, the only United Nations treaty ratified by every country in the world, was signed in 1987 and entered into effect in 1989, when little was known about its impact on the global climate. Its purpose was to reduce atmospheric concentrations of ozone-depleting substances (ODSs), materials commonly used in products such as refrigerators, air conditioners, fire extinguishers, and aerosols. For more than 50 years, it has been an important mitigation treaty, affecting many aspects of the global climate.

New study shows that the treaty's impact goes as far as the Arctic

A new study led by climate researchers at Columbia Engineering and the University of Exeter demonstrates that the treaty's impact reaches all the way into the Arctic: its implementation is delaying the occurrence of the first ice-free Arctic by as much as 15 years, depending on the details of future emissions. The study was published today by PNAS.

"The first ice-free Arctic summer-with the Arctic Ocean practically free of sea ice-will be a major milestone in the process of climate change, and our findings were a surprise to us," said the study's co-author Lorenzo Polvani, Maurice Ewing and J. Lamar Worzel Professor of Geophysics in the Department of Applied Physics and Applied Mathematics and professor of earth and environmental sciences. "Our results show that the climate benefits from the Montreal Protocol are not in some faraway future: the Protocol is delaying the melting of Arctic sea ice at this very moment. That's what a successful climate treaty does: it yields measurable results within a few decades of its implementation."

Impact of ODSs

Polvani noted that the rapid melting of Arctic sea ice is the largest and clearest signal of anthropogenic climate change. Current projections indicate that the first ice-free Arctic summer will likely occur by 2050, owing largely to increasing carbon dioxide concentrations in the atmosphere. However, other powerful greenhouse gases have also contributed to Arctic sea ice loss, notably ODSs. When ODSs became strictly regulated by the Montreal Protocol In the late 1980s, their atmospheric concentrations began to decline in the mid-1990s.

Polvani and his co-author Mark England, Royal Commission for the Exhibition of 1851 Senior Research Fellow at the University of Exeter and a former PhD student with Polvani, were particularly interested in exploring the impact of ODSs because their molecules, while a lot less common in the atmosphere, are tens of thousands of times more powerful at warming the planet than carbon dioxide.

Analysis of new climate model simulations

The researchers analyzed new climate model simulations and found that the Montreal Protocol is delaying the first appearance of an ice-free Arctic summer by up to 15 years, depending on future CO2 emissions. They compared the estimated warming from ODS with and without the Montreal Protocol under two scenarios of future CO2 emissions from 1985-2050. Their results show that if the Montreal Protocol had not been enacted, the estimated global mean surface temperature would be around 0.5 °C warmer and the Arctic polar cap would be almost 1 °C warmer in 2050.

"This important climate mitigation stems entirely from the reduced greenhouse gas warming from the regulated ODSs, with the avoided stratospheric ozone losses playing no role," said England. "While ODSs aren't as abundant as other greenhouse gasses such as carbon dioxide, they can have a real impact on global warming. ODSs have particularly powerful effects in the Arctic, and they were an important driver of Arctic climate change in the second half of the 20th Century. While stopping these effects was not the primary goal of the Montreal Protocol, it has been a fantastic by-product."

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Exercise seems to protect against major brain hemorrhage

Regular physical activity and exercise may reduce bleeding in individuals with intracerebral hemorrhage, a University of Gothenburg study shows. The researchers emphasize the importance of physical activity to protect the brain.

The study, published in the journal Stroke and Vascular Neurology, analyzed data on 686 people treated for intracerebral hemorrhage at Sahlgrenska University Hospital in Gothenburg during the years 2014 to 2019.

The results are based on a retrospective analysis. Causal connections cannot be identified, but the findings are nonetheless clear: Those who reported regular physical activity had smaller hemorrhages than those who reported being inactive.

Physically active was defined as engaging in at least light physical activity, such as walking, cycling, swimming, gardening, or dancing, for at least four hours weekly.

50 percent less bleeding volume

The main author of the study is Adam Viktorisson, a PhD student in clinical neuroscience at Sahlgrenska Academy, University of Gothenburg, and doctor in general practice at Sahlgrenska University Hospital.

"We found that individuals who engage in regular physical activity had, on average, bleeding volumes that were 50 percent smaller upon arriving to the hospital. A similar connection has previously been seen in animal studies, but no prior study has demonstrated this in humans."

Everyone who comes to the hospital with a suspected intracerebral hemorrhage undergoes a computerized tomography (CT) scan of the brain. Depending on the severity of the hemorrhage, neurosurgery may be required. However, in most cases, non-surgical methods and medications are used to manage symptoms and promote patient recovery.

Intracerebral hemorrhage is the most dangerous type of stroke and can lead to life-threatening conditions. The risk of severe consequences from the hemorrhage increases with the extent of the bleeding.

"In cases of major intracerebral hemorrhages, there is a risk of increased pressure within the skull that can potentially lead to fatal outcomes" says Thomas Skoglund, associate professor of neurosurgery at the University of Gothenburg, neurosurgeon at the University Hospital, and one of the study's co-authors.

Better understanding of intracerebral hemorrhages

The findings were significant regardless of the location within the cerebrum. Physically active individuals exhibited reduced bleeding in both the deep regions of the brain, which are often associated with high blood pressure, and the surface regions, which are linked to age-related conditions like dementia.

The study creates scope for further research on intracerebral hemorrhages and physical activity. Katharina Stibrant Sunnerhagen, professor of rehabilitation medicine at the University of Gothenburg and senior consultant physician at Sahlgrenska University Hospital, oversees the study.

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Oldest architectural plans detail mysterious desert mega structures

An international team of researchers including the University of Freiburg identifies engravings in Jordan and Saudi Arabia as the oldest known scaled building plans in human history.

Although human constructions have modified natural spaces for millennia, few plans or maps predate the period of the literate civilizations of Mesopotamia and Ancient Egypt. Researchers from the French research organisation "Centre national de la recherche scientifique" (CNRS), together with Prof. Dr. Frank Preusser from the University of Freiburg, have now been able to identify engravings in Jordan and Saudi Arabia as the oldest known true-to-scale construction plans in human history. The 8,000 to 9,000-year-old engravings depict so-called desert dragons -- kilometre long prehistoric megastructures used to trap animals. "Conclusions can be drawn from the findings about the people of the time. The ability to transfer a large space to a small, two-dimensional plan represents a milestone in intelligent behaviour," explains Preusser. The results, which were published in mid-May in the scientific journal PLOS ONE, should help to understand how desert dragons were conceived and built.

Scale plans of desert dragons discovered in Jordan and Saudi Arabia

Both finds are representations of nearby desert dragons engraved with stone tools. First sighted from aircrafts in the 1920s, desert dragons, up to five kilometres long, consist of stone walls that converge in a complex bounded by pits. As archaeologists have been able to determine in recent years, they were used for large-scale trapping of wild animals. In Jordan, there are eight desert dragons in the area of Jibal al-Khasabiyeh. There, the researchers found a depiction engraved in stone that measures 80 by 32 cm, its age is about 9,000 years. At Jebel az-Zilliyat in Saudi Arabia, two visible pairs of dragons are found three and a half kilometres apart. Here, too, a scaled engraving dating back about 8,000 years was discovered with a total length of 382 cm and a width of 235 cm.

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An X-ray look at the heart of powerful quasars

Researchers have observed the X-ray emission of the most luminous quasar seen in the last 9 billion years of cosmic history, known as SMSS J114447.77-430859.3, or J1144 for short. The new perspective sheds light on the inner workings of quasars and how they interact with their environment. The research is published in Monthly Notices of the Royal Astronomical Society.

Hosted by a galaxy 9.6 billion light years away from the Earth, between the constellations of Centaurus and Hydra, J1144 is extremely powerful, shining 100,000 billion times brighter than the Sun. J1144 is much closer to Earth than other sources of the same luminosity, allowing astronomers to gain insight into the black hole powering the quasar and its surrounding environment. The study was led by Dr Elias Kammoun, a postdoctoral researcher at the Research Institute in Astrophysics and Planetology (IRAP), and Zsofi Igo, a PhD candidate at the Max Planck Institute for Extraterrestrial Physics (MPE).

Quasars are among the brightest and most distant objects in the known universe, powered by the fall of gas into a supermassive black hole. They can be described as active galactic nuclei (AGN) of very high luminosity that emit vast amounts of electromagnetic radiation observable in radio, infrared, visible, ultraviolet and X-ray wavelengths. J1144 was initially observed in visible wavelengths in 2022 by the SkyMapper Southern Survey (SMSS).

For this study, researchers combined observations from several space-based observatories: the eROSITA instrument on board the Spectrum-Roentgen-Gamma (SRG) observatory, the ESA XMM-Newton observatory, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), and NASA's Neil Gehrels Swift observatory.

The team used the data from the four observatories to measure the temperature of the X-rays being emitted from the quasar. They found this temperature to be around 350 million Kelvin, more than 60,000 times the temperature at the surface of the Sun. The team also found that the mass of the black hole at the quasar's centre is around 10 billion times the mass of the Sun, and the rate at which it is growing to be of the order of 100 solar masses per year.

The X-ray light from this source varied on a time scale of a few days, which is not usually seen in quasars with black holes as large as the one residing in J1144. The typical timescale of variability for a black hole of this size would be on the order of months or even years. The observations also showed that while a portion of the gas is swallowed by the black hole, some gas is ejected in the form of extremely powerful winds, injecting large amounts of energy into the host galaxy.

Dr. Kammoun, lead author of the paper, says "We were very surprised that no prior X-ray observatory has ever observed this source despite its extreme power."

He adds, "Similar quasars are usually found at much larger distances, so they appear much fainter, and we see them as they were when the Universe was only 2-3 billion years old. J1144 is a very rare source as it is so luminous and much closer to Earth (although still at a huge distance!), giving us a unique glimpse of what such powerful quasars look like."

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Fossils of a saber-toothed top predator reveal a scramble for dominance leading up to 'the Great Dying'

A tiger-sized saber-toothed creature called Inostrancevia has previously only been found in Russia. But scientists have discovered its fossils in South Africa, suggesting that it migrated 7,000 miles across the supercontinent Pangaea during the world's worst mass extinction 252 million years ago. Heading to South Africa allowed it to fill a gap in a faraway ecosystem that had lost its top predators.

Two hundred and fifty-two million years ago, Earth experienced a mass extinction so devastating that it's become known as "the Great Dying." Massive volcanic eruptions triggered catastrophic climate change, killing off nine out of every ten species and eventually setting the stage for the dinosaurs. But the Great Dying was a long goodbye -- the extinction event took place over the course of up to a million years at the end of the Permian period. During that time, the fossil record shows drama and upheaval as species fought to get a foothold in their changing environments. One animal that exemplifies this instability was a tiger-sized, saber-toothed creature called Inostrancevia: a new fossil discovery suggests that Inostrancevia migrated 7,000 miles across the supercontinent Pangaea, filling a gap in a faraway ecosystem that had lost its top predators, before going extinct itself.

"All the big top predators in the late Permian in South Africa went extinct well before the end-Permian mass extinction. We learned that this vacancy in the niche was occupied, for a brief period, by Inostrancevia," says Pia Viglietti, a research scientist at the Field Museum in Chicago and a co-author of the new study in Current Biology.

The prehistoric creature looked the part of "top predator." "Inostrancevia was a gorgonopsian, a group of proto-mammals that included the first saber-toothed predators on the planet," says Viglietti. It was about the size of a tiger and likely had skin like an elephant or a rhino; while vaguely reptilian in appearance, it was part of the group of animals that includes modern mammals.

Prior to this new paper, Inostrancevia had only ever been found in Russia. But while examining the fossil record of South Africa's Karoo Basin, Viglietti's colleague Christian Kammerer identified the fossils of two large predatory animals that were different from those normally found in the region. "The fossils themselves were quite unexpected," says Viglietti. It's not clear how they made it from what's now Russia, or how long it took them to cross Pangaea and arrive in what's now South Africa. But being far from home was just one element of what made the fossils special.

"When we reviewed the ranges and ages of the other top predators normally found in the area, the rubidgeine gorgonopsians, with these Inostrancevia fossils, we found something quite exciting," she says. "The local carnivores actually went extinct quite a bit before even the main extinction that we see in the Karoo -- by the time the extinction begins in other animals, they're gone."

The arrival of Inostrancevia from 7,000 miles away and its subsequent extinction indicates that these top predators were "canaries in the coal mine" for the larger extinction event to come.

"This shows that the South African Karoo Basin continues to produce critical data for understanding the most catastrophic mass extinction in Earth's history," says co-author Jennifer Botha, director of GENUS Centre of Excellence in Palaeosciences and professor at the Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg.

"We have shown that the shift in which groups of animals occupied apex predator roles occurred four times over less than two million years around the Permian-Triassic mass extinction, which is unprecedented in the history of life on land. This underlines how extreme this crisis was, with even fundamental roles in ecosystems in extreme flux," said Christian Kammerer, the study's first author and a research curator of paleontology at the North Carolina Museum of Natural Sciences and research associate at the Field Museum.

The vulnerability of these top predators matches what we see today. "Apex predators in modern environments tend to show high extinction risk, and tend to be among the first species that are locally extirpated due to human-mediated activities such as hunting or habitat destruction," says Kammerer. "Think about wolves in Europe or tigers in Asia, species which tend to be slow to reproduce and grow and require large geographic areas to roam and hunt prey, and which are now absent from most of their historic ranges. We should expect that ancient apex predators would have had similar vulnerabilities, and would be among the species that first go extinct during mass extinction events."

In addition to shedding new light on the extinction event that helped lead to the rise of the dinosaurs, Viglietti says that the study is important for what it can teach us about the ecological disasters the planet is currently experiencing.

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