Eruption of Tonga underwater volcano found to disrupt satellite signals halfway around the world

An international team has used satellite- and ground-based ionospheric observations to demonstrate that an air pressure wave triggered by volcanic eruptions could produce an equatorial plasma bubble (EPB) in the ionosphere, severely disrupting satellite-based communications. Their findings were published in the journal Scientific Reports.

The ionosphere is the region of the Earth's upper atmosphere where molecules and atoms are ionized by solar radiation, creating positively charged ions. The area with the highest concentration of ionized particles is called the F-region, an area 150 to 800 km above the Earth's surface. The F-region plays a crucial role in long-distance radio communication, reflecting and refracting radio waves used by satellite and GPS tracking systems back to the Earth's surface.

These important transmissions can be disrupted by irregularities in the F-region. During the day, the ionosphere is ionized by the Sun's ultraviolet radiation, creating a density gradient of electrons with the highest density near the equator. However, disruptions to this, such as the movement of plasma, electric fields, and neutral winds, can cause the formation of a localized irregularity of enhanced plasma density. This region can grow and evolve, creating a bubble-like structure called an EPB. EPB can delay radio waves and degrade the performance of GPS.

Since these density gradients can be affected by atmospheric waves, it has long been hypothesized that they are formed by terrestrial events such as volcanic activity. For an international team led by Designated Assistant Professor Atsuki Shinbori (he, him) and Professor Yoshizumi Miyoshi (he, him) of the Institute for Space-Earth Environmental Research (ISEE), Nagoya University, in collaboration with NICT, The University of Electro-Communications, Tohoku University, Kanazawa University, Kyoto University and ISAS, the Tonga volcano eruption offered them a perfect opportunity to test this theory.

The Tonga volcano eruption was the biggest submarine eruption in history. This allowed the team to test their theory using the Arase satellite to detect EPB occurrences, the Himawari-8 satellite to check the initial arrival of air pressure waves and ground-based ionospheric observations to track the motion of the ionosphere. They observed an irregular structure of the electron density across the equator that occurred after the arrival of pressure waves generated by the volcanic eruption.

"The results of this study showed EPBs generated in the equatorial to low-latitude ionosphere in Asia in response to the arrival of pressure waves caused by undersea volcanic eruptions off Tonga," Shinbori said.

The group also made a surprising discovery. For the first time, they showed that ionospheric fluctuations start a few minutes to a few hours earlier than the atmospheric pressure waves involved in the generation of plasma bubbles. This could have important implications because it suggests that the long-held model of geosphere-atmosphere-cosmosphere coupling, which states that ionospheric disturbances only happen after the eruption, needs revision.

"Our new finding is that the ionospheric disturbances are observed several minutes to hours before the initial arrival of the shock waves triggered by the Tonga volcanic eruption," Shinbori said. "This suggests that the propagation of the fast atmospheric waves in the ionosphere triggered the ionospheric disturbances before the initial arrival of the shock waves. Therefore, the model needs to be revised to account for these fast atmospheric waves in the ionosphere."

They also found that the EPB extended much further than predicted by the standard models. "Previous studies have shown that the formation of plasma bubbles at such high altitudes is a rare occurrence, making this a very unusual phenomenon," Shinbori said. "We found that the EPB formed by this eruption reached space even beyond the ionosphere, suggesting that we should pay attention to the connection between the ionosphere and the cosmosphere when extreme natural phenomenon, such as the Tonga event, occur."

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Half of world's largest lakes losing water

More than 50 percent of the largest lakes in the world are losing water, according to a groundbreaking new assessment published today in Science . The key culprits are not surprising: warming climate and unsustainable human consumption.

But lead author Fangfang Yao, a CIRES visiting fellow, now a climate fellow at University of Virginia, said the news is not entirely bleak. With this new method of tracking lake water storage trends and the reasons behind them, scientists can give water managers and communities insight into how to better protect critical sources of water and important regional ecosystems.

"This is the first comprehensive assessment of trends and drivers of global lake water storage variability based on an array of satellites and models," Yao said.

He was motivated to do the research by the environmental crises in some of Earth's largest water bodies, such as the drying of the Aral Sea between Kazakhstan and Uzbekistan.

So he and colleagues from the University of Colorado Boulder, Kansas State University, France, and Saudi Arabia created a technique to measure changes in water levels in nearly 2,000 of the world's biggest lakes and reservoirs, which represent 95 percent of the total lake water storage on Earth.

The team combined three decades of observations from an array of satellites with models to quantify and attribute trends in lake storage globally.

Globally, freshwater lakes and reservoirs store 87 percent of the planet's water, making them a valuable resource for both human and Earth ecosystems. Unlike rivers, lakes are not well monitored, yet they provide water for a large part of humanity -- even more than rivers.

But despite their value, long-term trends and changes to water levels have been largely unknown -- until now.

"We have pretty good information on iconic lakes like Caspian Sea, Aral Sea and Salton Sea, but if you want to say something on a global scale, you need reliable estimates of lake levels and volume," said Balaji Rajagopalan, a CIRES fellow, professor of engineering at CU Boulder, and co-author. "With this novel method …we are able to provide insights into global lake level changes with a broader perspective."

For the new paper, the team used 250,000 lake-area snapshots captured by satellites between 1992-2020 to survey the area of 1,972 of Earth's biggest lakes. They collected water levels from nine satellite altimeters and used long-term water levels to reduce any uncertainty. For lakes without a long-term level record, they used recent water measurements made by newer instruments on satellites. Combining recent level measurements with longer-term area measurements allowed scientists to reconstruct the volume of lakes dating back decades.

The results were staggering: 53 percent of lakes globally experienced a decline in water storage. The authors compare this loss with the magnitude of 17 Lake Meads, the largest reservoir in the United States.

To explain the trends in natural lakes, the team leveraged recent advancements in water use and climate modeling. Climate change and human water consumption dominated the global net decline in natural lake volume and water losses in about 100 large lakes, Yao said. "And many of the human and climate change footprints on lake water losses were previously unknown, such as the desiccations of Lake Good-e-Zareh in Afghanistan and Lake Mar Chiquita in Argentina."

Lakes in both dry and wet areas of the world are losing volume. The losses in humid tropical lakes and Arctic lakes indicate more widespread drying trends than previously understood.

Yao and his colleagues also assessed storage trends in reservoirs. They found that nearly two-thirds of Earth's large reservoirs experienced significant water losses.

"Sedimentation dominated the global storage decline in existing reservoirs," said Ben Livneh, also a co-author, CIRES fellow, and associate professor of engineering at CU Boulder. In long-established reservoirs -- those that filled before 1992 -- sedimentation was more important than droughts and heavy rainfall years.

While the majority of global lakes are shrinking, 24 percent saw significant increases in water storage. Growing lakes tend to be in underpopulated areas in the inner Tibetan Plateau and Northern Great Plains of North America and in areas with new reservoirs such as the Yangtze, Mekong, and Nile river basins.

The authors estimate roughly one-quarter of the world's population, 2 billion people, resides in the basin of a drying lake, indicating an urgent need to incorporate human consumption, climate change, and sedimentation impacts into sustainable water resources management.

And their research offers insight into possible solutions, Livneh said. "If human consumption is a large factor in lake water storage decline, then we can adapt and explore new policies to reduce large-scale declines."

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Skin patch shows promise for toddlers with peanut allergy

A global phase 3 clinical trial that included Ann & Robert H. Lurie Children's Hospital of Chicago found that a year-long immunotherapy through a skin patch safely desensitized toddlers with peanut allergy, lowering the risk of a severe allergic reaction from accidental exposure. Results of this randomized, double-blind, placebo-controlled trial for children 1-3 years of age, funded by DBV Technologies, were published in the New England Journal of Medicine.

"We were excited to contribute to this landmark study that carries so much promise for our young patients with peanut allergy," said co-author Melanie Makhija, MD, who was the Principal Investigator of the study at Lurie Children's and is an Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine. "Children who originally reacted to a small fraction of a peanut were able to tolerate the equivalent of one to four peanuts after completing the treatment course. This means that these children will be well protected from accidental exposure to peanuts. Importantly, we found that the peanut patch was safe, with very low chances of a severe allergic reaction. This is terrific news for families of kids with peanut allergies."

Peanut allergy affects approximately 2 percent of children in the United States, Canada and other westernized countries, and it commonly persists into adulthood. Life-threatening allergic reactions can be triggered by unintentional exposure to minute quantities, including through products manufactured on shared equipment as peanuts. Currently, there are no approved treatments for peanut-allergic children younger than 4 years of age.

Since 2012, the clinical trials program for food allergies at Lurie Children's has enrolled patients on numerous studies of novel treatments, including the oral immunotherapy for peanuts that has been approved by the Food and Drug Administration (FDA). Ongoing trials are available for all age groups, from infancy to young adulthood. The program is led by Principal Investigators Elizabeth Lippner, MD, and Abigail Lang, MD, MSCI.

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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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