Two largest Mars-quakes to date recorded from planet's far side

The seismometer placed on Mars by NASA's InSight lander has recorded its two largest seismic events to date: a magnitude 4.2 and a magnitude 4.1 marsquake. The pair are the first recorded events to occur on the planet's far side from the lander and are five times stronger than the previous largest event recorded.

Seismic wave data from the events could help researchers learn more about the interior layers of Mars, particularly its core-mantle boundary, researchers from InSight's Marsquake Service (MQS) report in The Seismic Record.

Anna Horleston of the University of Bristol and colleagues were able to identify reflected PP and SS waves from the magnitude 4.2 event, called S0976a, and locate its origin in the Valles Marineris, a massive canyon network that is one of Mars' most distinguishing geological features and one of the largest graben systems in the Solar System. Earlier orbital images of cross-cutting faults and landslides suggested the area would be seismically active, but the new event is the first confirmed seismic activity there.

S1000a, the magnitude 4.1 event recorded 24 days later, was characterized by reflected PP and SS waves as well as Pdiff waves, small amplitude waves that have traversed the core-mantle boundary. This is the first time Pdiff waves have been spotted by the InSight mission. The researchers could not definitively pinpoint S1000a's location, but like S0976a it originated on Mars' far side. The seismic energy from S1000a also holds the distinction of being the longest recorded on Mars, lasting 94 minutes.

Both marsquakes occurred in the core shadow zone, a region where P and S waves can't travel directly to InSight's seismometer because they are stopped or bent by the core. PP and SS waves don't follow a direct path, but rather are reflected at least once at the surface before traveling to the seismometer.

"Recording events within the core shadow zone is a real steppingstone for our understanding of Mars. Prior to these two events the majority of the seismicity was within about 40 degrees distance of InSight," said Savas Ceylan, a co-author from ETH Zürich. "Being within the core shadow, the energy traverses parts of Mars we have never been able to seismologically sample before."

The two marsquakes differ in some important ways. S0976a is characterized by only low frequency energy, like many of the quakes identified so far on the planet, while S1000a has a very broad frequency spectrum. "[S1000a] is a clear outlier in our catalog and will be key to our further understanding of Martian seismology," Horleston said.

S0976a is likely to have a much deeper origin than S1000a, she noted. "The latter event has a frequency spectrum much more like a family of events that we observe that have been modeled as shallow, crustal quakes, so this event may have occurred near the surface. S0976a looks like many of the events we have located to Cerberus Fossae -- an area of extensive faulting -- that have depths modeled to be around 50 kilometers or more and it is likely that this event has a similar, deep, source mechanism."

Compared to the rest of the seismic activity detected by InSight, the two new far-side quakes are true outliers, the researchers said.

Read more at Science Daily

New miniature heart could help speed heart disease cures

There's no safe way to get a close-up view of the human heart as it goes about its work: you can't just pop it out, take a look, then slot it back in. Scientists have tried different ways to get around this fundamental problem: they've hooked up cadaver hearts to machines to make them pump again, attached lab-grown heart tissues to springs to watch them expand and contract. Each approach has its flaws: reanimated hearts can only beat for a few hours; springs can't replicate the forces at work on the real muscle. But getting a better understanding of this vital organ is urgent: in America, someone dies of heart disease every 36 seconds, according to the Centers for Disease Control and Prevention.

Now, an interdisciplinary team of engineers, biologists, and geneticists has developed a new way of studying the heart: they've built a miniature replica of a heart chamber from a combination of nanoengineered parts and human heart tissue. There are no springs or external power sources -- like the real thing, it just beats by itself, driven by the live heart tissue grown from stem cells. The device could give researchers a more accurate view of how the organ works, allowing them to track how the heart grows in the embryo, study the impact of disease, and test the potential effectiveness and side effects of new treatments -- all at zero risk to patients and without leaving a lab.

The Boston University-led team behind the gadget -- nicknamed miniPUMP, and officially known as the cardiac miniaturized Precision-enabled Unidirectional Microfluidic Pump -- says the technology could also pave the way for building lab-based versions of other organs, from lungs to kidneys. Their findings have been published in Science Advances.

"We can study disease progression in a way that hasn't been possible before," says Alice White, a BU College of Engineering professor and chair of mechanical engineering. "We chose to work on heart tissue because of its particularly complicated mechanics, but we showed that, when you take nanotechnology and marry it with tissue engineering, there's potential for replicating this for multiple organs."

According to the researchers, the device could eventually speed up the drug development process, making it faster and cheaper. Instead of spending millions -- and possibly decades -- moving a medicinal drug through the development pipeline only to see it fall at the final hurdle when tested in people, researchers could use the miniPUMP at the outset to better predict success or failure.

The project is part of CELL-MET, a multi-institutional National Science Foundation Engineering Research Center in Cellular Metamaterials that's led by BU. The center's goal is to regenerate diseased human heart tissue, building a community of scientists and industry experts to test new drugs and create artificial implantable patches for hearts damaged by heart attacks or disease.

"Heart disease is the number one cause of death in the United States, touching all of us," says White, who was chief scientist at Alcatel-Lucent Bell Labs before joining BU in 2013. "Today, there is no cure for a heart attack. The vision of CELL-MET is to change this."

Personalized Medicine

There's a lot that can go wrong with your heart. When it's firing properly on all four cylinders, the heart's two top and two bottom chambers keep your blood flowing so that oxygen-rich blood circulates and feeds your body. But when disease strikes, the arteries that carry blood away from your heart can narrow or become blocked, valves can leak or malfunction, the heart muscle can thin or thicken, or electrical signals can short, causing too many -- or too few -- beats. Unchecked, heart disease can lead to discomfort -- like breathlessness, fatigue, swelling, and chest pain -- and, for many, death.

"The heart experiences complex forces as it pumps blood through our bodies," says Christopher Chen, BU's William F. Warren Distinguished Professor of Biomedical Engineering. "And while we know that heart muscle changes for the worse in response to abnormal forces -- for example, due to high blood pressure or valve disease -- it has been difficult to mimic and study these disease processes. This is why we wanted to build a miniaturized heart chamber."

At just 3 square centimeters, the miniPUMP isn't much bigger than a postage stamp. Built to act like a human heart ventricle -- or muscular lower chamber -- its custom-made components are fitted onto a thin piece of 3D-printed plastic. There are miniature acrylic valves, opening and closing to control the flow of liquid -- water, in this case, rather than blood -- and small tubes, funneling that fluid just like arteries and veins. And beating away in one corner, the muscle cells that make heart tissue contract, cardiomyocytes, made using stem cell technology.

"They're generated using induced pluripotent stem cells," says Christos Michas (ENG'21), a postdoctoral researcher who designed and led the development of the miniPUMP as part of his PhD thesis.

To make the cardiomyocyte, researchers take a cell from an adult -- it could be a skin cell, blood cell, or just about any other cell -- reprogram it into an embryonic-like stem cell, then transform that into the heart cell. In addition to giving the device literal heart, Michas says the cardiomyocytes also give the system enormous potential in helping pioneer personalized medicines. Researchers could place a diseased tissue in the device, for instance, then test a drug on that tissue and watch to see how its pumping ability is impacted.

"With this system, if I take cells from you, I can see how the drug would react in you, because these are your cells," says Michas. "This system replicates better some of the function of the heart, but at the same time, gives us the flexibility of having different humans that it replicates. It's a more predictive model to see what would happen in humans -- without actually getting into humans."

According to Michas, that could allow scientists to assess a new heart disease drug's chances of success long before heading into clinical trials. Many drug candidates fail because of their adverse side effects.

"At the very beginning, when we're still playing with cells, we can introduce these devices and have more accurate predictions of what will happen in clinical trials," says Michas. "It will also mean that the drugs might have fewer side effects."

Thinner than a Human Hair

One of the key parts of the miniPUMP is an acrylic scaffold that supports, and moves with, the heart tissue as it contracts. A series of superfine concentric spirals -- thinner than a human hair -- connected by horizontal rings, the scaffold looks like an artsy piston. It's an essential piece of the puzzle, giving structure to the heart cells -- which would just be a formless blob without it -- but not exerting any active force on them.

"We don't think previous methods of studying heart tissue capture the way the muscle would respond in your body," says Chen, who's also director of BU's Biological Design Center and an associate faculty member at Harvard University's Wyss Institute for Biologically Inspired Engineering. "This gives us the first opportunity to build something that mechanically is more similar to what we think the heart is actually experiencing -- it's a big step forward."

To print each of the tiny components, the team used a process called two-photon direct laser writing -- a more precise version of 3D printing. When light is beamed into a liquid resin, the areas it touches turn solid; because the light can be aimed with such accuracy -- focused to a tiny spot -- many of the components in the miniPUMP are measured in microns, smaller than a dust particle.

The decision to make the pump so small, rather than life-size or larger, was deliberate and is crucial to its functioning.

"The structural elements are so fine that things that would ordinarily be stiff are flexible," says White. "By analogy, think about optical fiber: a glass window is very stiff, but you can wrap a glass optical fiber around your finger. Acrylic can be very stiff, but at the scale involved in the miniPUMP, the acrylic scaffold is able to be compressed by the beating cardiomyocytes."

Chen says that the pump's scale shows "that with finer printing architectures, you might be able to create more complex organizations of cells than we thought was possible before." At the moment, when researchers try to create cells, he says, whether heart cells or liver cells, they're all disorganized -- "to get structure, you have to cross your fingers and hope the cells create something." That means the tissue scaffolding pioneered in the miniPUMP has big potential implications beyond the heart, laying the foundation for other organs-on-a-chip, from kidneys to lungs.

Refining the Technology

According to White, the breakthrough is possible because of the range of experts on CELL-MET's research team, which included not just mechanical, biomedical, and materials engineers like her, Chen, and Arvind Agarwal of Florida International University, but also geneticist Jonathan G. Seidman of Harvard Medical School and cardiovascular medicine specialist Christine E. Seidman of Harvard Medical School and Brigham and Women's Hospital. It's a breadth of experience that's benefited not just the project, but Michas. An electrical and computer engineering student as an undergraduate, he says he'd "never seen cells in my life before starting this project." Now, he's preparing to start a new position with Seattle-based biotech Curi Bio, a company that combines stem cell technology, tissue biosystems, and artificial intelligence to power the development of drugs and therapeutics.

"Christos is someone who understands the biology," says White, "can do the cell differentiation and tissue manipulation, but also understands nanotechnology and what's required, in an engineering way, to fabricate the structure."

Read more at Science Daily

Deepest sediment core collected in the Atlantic Ocean

A team of scientists, engineers, and ship's crew on the research vessel Neil Armstrong operated by the Woods Hole Oceanographic Institution (WHOI) recently collected a 38-foot-long cylindrical sediment sample from the deepest part of the Puerto Rico Trench, nearly 5 miles below the surface. The sample core is breaking records as the deepest ever collected in the Atlantic Ocean, and possibly the deepest core collected in any ocean.

The event took place aboard a collaborative cruise in Puerto Rico between February and March, 2022. The group responsible for the core collection was led by Prof. Steven D'Hondt and Dr. Robert Pockalny from the University of Rhode Island's Graduate School of Oceanography and included researchers and technicians from WHOI, University of Rhode Island, University of California San Diego, Oregon State University, University of Washington, University of Puerto Rico Mayagüez, and University of Munich.

Long sediment cores are generally collected by allowing a core pipe with a lead weight on top to fall through the water and into soft sediment that collects on the seafloor over long periods of time. When the pipe is pulled out of the seafloor and back up to the ship, the recovered sediment inside can be used to study Earth's environmental conditions and climate dating back tens or hundreds of thousands, or even millions, of years ago.

Scientists are also interested in understanding genetic traits that enable microscopic organisms to survive within seafloor sediments. The main objective of this expedition was to better understand how microbes at different depths below the seafloor have adapted to vastly different environmental conditions present across the entire depth range of the trench. Over the course of three weeks at sea, the team collected cores from a water depth of about 50 meters (165 feet) to the trench's maximum depth of about 8,385 meters (27,510 feet).

"We took these cores to learn how microbes that live beneath the seafloor respond to pressure," said D'Hondt. "Our ultimate objective is to improve understanding of how organisms in extreme environments engage in the world around them. "Our team's success in extracting this core from the deepest part of the Atlantic Ocean will enable us to make a tremendous advance in our understanding of this little-known part of life on Earth."

The core collections were made possible by the long core system originally developed at WHOI in 2007 by then-research specialist Jim Broda for the research vessel Knorr. After the ship's retirement, the system was adapted to fit the slightly shorter vessel Neil Armstrong. After this expedition, the long corer will be transferred to the OSU Marine Sediment Sampling Group, which is funded by the U.S. National Science Foundation and supports coring operations throughout the U.S. academic research fleet, so it can be made available to the entire oceanographic community.

Read more at Science Daily

Indiana Jones was right all along: Research shows the smaller the scorpion, the deadlier

Researchers in NUI Galway have shown, for the first time, that smaller species of scorpions, with smaller pincers, have more potent venoms compared to larger species with robust claws.

The scientists tested the theory from Indiana Jones and the Kingdom of the Crystal Skull, which warned of the dangers of small scorpions, and that "when it comes to scorpions, the bigger the better."

While this may have simply been a throwaway movie line from the adventurous archaeologist Indiana Jones, the research shows there is truth to it.

The team of scientists at NUI Galway's Ryan Institute put the quip to the test by analysing 36 species of scorpions to show that larger scorpions have less potent venoms and really are better in terms of avoiding a nasty sting.

The results of the research have published in the international journal Toxins.

It shows the smallest scorpions in their analysis, like the Brazilian yellow scorpion, where over 100 times more potent than the largest species they studied, such as the rock scorpion.

The potency pattern was not just about body size, but also pincer size, with venoms found in species with the smallest pinchers, including the South African thick-tail scorpion, which is more than 10 times more potent compared to species with the largest and most robust pinchers, such as the Israeli gold scorpion.

Dr Kevin Healy, Lecturer of Zoology at NUI Galway and senior author of the study, said: "Outside of entertaining movie trivia there are good evolutionary reason to expect the results and important medical implications for such patterns."

The researchers highlighted that while scorpions use both their venomous sting and their pinchers to capture prey and for defence there is an evolutionary trade-off between these weapons. Energy used to make bigger pincers means less energy is available for its chemical arsenal. This results in larger scorpions which can use their physical size are less reliant on venoms, while smaller species have evolved more potent venoms.

Dr Healy added: "When we look at the most potent, and dangerous, scorpion venoms we find they tend to be associated with species such as the deathstalker which are relatively small. In contrast, the biggest species such as rock scorpions have venoms that are likely to only cause slight pain."

Alannah Forde, an NUI Galway graduate student and lead author of the study, said: "Not only did we find that bigger is better -- when it comes to people being stung -- we also found that bigger pincers are better when it comes to assessing the danger level of a scorpion. While species such as large-clawed scorpion might be small to medium in size, they mainly rely on their large pincers instead of their relatively weak venom."

Scorpion stings are a global health problem with more than 1 million cases and thousands of deaths every year. Identifying the species involved with a sting is vital for treatment, hence general rules such as "bigger is better" are often used to help with treatment.

The team aim to test these evolutionary rules to what makes some species more potent to help develop better medical approaches to scorpion stings.

Read more at Science Daily

Evidence suggests cancer is not as purely genetic as once thought

While cancer is a genetic disease, the genetic component is just one piece of the puzzle -- and researchers need to consider environmental and metabolic factors as well, according to a research review by a leading expert at the University of Alberta.

Nearly all the theories about the causes of cancer that have emerged over the past several centuries can be sorted into three larger groups, said David Wishart, professor in the departments of biological sciences and computing science. The first is cancer as a genetic disease, focusing on the genome, or the set of genetic instructions that you are born with. The second is cancer as an environmental disease, focusing on the exposome, which includes everything your body is exposed to throughout your life. The third is cancer as a metabolic disease, focusing on the metabolome, all the chemical byproducts of the process of metabolism.

The metabolic perspective hasn't had much research until now, but it's gaining the interest of more scientists, who are beginning to understand the metabolome's role in cancer.

The genome, exposome and metabolome operate together in a feedback loop as cancer develops and spreads.

According to the data, heritable cancers account for just five to 10 per cent of all cancers, Wishart said. The other 90 to 95 per cent are initiated by factors in the exposome, which in turn trigger genetic mutations.

"That's an important thing to consider, because it says that cancer isn't inevitable."

The metabolome is critical to the process, as those genetically mutated cancer cells are sustained by the cancer-specific metabolome.

"Cancer is genetic, but often the mutation itself isn't enough," said Wishart. As cancer develops and spreads in the body, it creates its own environment and introduces certain metabolites. "It becomes a self-fuelled disease. And that's where cancer as a metabolic disorder becomes really important."

The multi-omics perspective, in which the genome, exposome and metabolome are all considered in unison when thinking about cancer, is showing promise for finding treatments and for overcoming the limitations of looking at only one of these factors.

For example, Wishart explained, researchers who focus only on the genetic perspective are looking to address particular mutations. The problem is, there are around 1,000 genes that can become cancerous when mutated, and it typically takes at least two different mutations within these cells for cancer to grow. That means there are a million potential mutation pairs, and "it becomes hopeless" to narrow down the possibilities when seeking new treatments.

But when considering cancer from the metabolic perspective, there are just four major metabolic types, said Wishart. Rather than trying to find a treatment plan for one specific mutation combination amongst a million, determining the patient's cancer metabolic type can immediately guide doctors in deciding on the best treatment for their specific cancer.

"It really doesn't make a difference where the cancer is -- it's something you've got to get rid of. It's how it thrives or grows that matters," said Wishart. "It becomes a question of, 'What's the fuel that powers this engine?'"

Wishart cautioned that health-care providers still need a mix of therapeutics for cancer, and noted that a deeper understanding of the metabolome and its role in the cancer feedback loop is also critical to preventing cancer.

"If we understand the causes of cancer, then we can start highlighting the known causes, the lifestyle issues that introduce or increase our risk," he said.

Read more at Science Daily

Earliest geochemical evidence of plate tectonics found in 3.8-billion-year-old crystal

A handful of ancient zircon crystals found in South Africa hold the oldest evidence of subduction, a key element of plate tectonics, according to a new study published today in AGU Advances, AGU's journal for high-impact, open-access research and commentary across the Earth and space sciences.

These rare time capsules from Earth's youth point to a transition around 3.8 billion years ago from a long-lived, stable rock surface to the active processes that shape our planet today, providing a new clue in a hot debate about when plate tectonics was set in motion.

Earth's crust and the top layer of mantle just under it are broken up into rigid plates that move slowly on top of viscous but mobile lower layers of mantle rock. Heat from Earth's core drives this slow but inexorable motion, responsible for volcanoes, earthquakes, and the uplift of mountain ranges.

Estimates for when this process revved up and modern crust formed range from over 4 billion years ago to just 800 million years ago. Uncertainty arises because the geologic record from Earth's youth is sparse, due to the surface recycling effect of plate tectonics itself. Almost nothing remains from the Hadean Eon, Earth's first 500 million years.

"The Hadean Earth is this big mystery box," said Nadja Drabon, a geologist at Harvard University and the lead author of the new study.

Tiny time capsules

In an exciting step forward in solving this mystery, in 2018 Drabon and her colleagues unearthed a chronological series of 33 microscopic zircon crystals from a rare, ancient block of crust in the Barberton Greenstone Belt in South Africa, that formed at different times over a critical 800-million-year span from 4.15 to 3.3 billion years ago.

Zircon is a relatively common accessory mineral in Earth's crust, but ancient representatives from the Hadean Eon, 4 to 4.56 billion years ago, are exceedingly rare, found in only 12 places on Earth, and usually in numbers fewer than three at each location.

Hafnium isotopes and trace elements preserved in the Greenstone Belt zircons told a story about the conditions on Earth at the time they crystalized. Zircons 3.8-billion-years-old and younger appeared to have formed in rock experiencing pressures and melting similar to modern subduction zones, suggesting the crust may have started moving.

"When I say plate tectonics, I'm specifically referring to an arc setting, when one plate goes under another and you have all that volcanism -- think of the Andes, for example, and the Ring of Fire," Drabon said, describing a classic example of subduction.

"At 3.8 billion years there is a dramatic shift where the crust is destabilized, we have new rocks forming and we see geochemical signatures becoming more and more similar to what we see in modern plate tectonics," Drabon said.

In contrast, the older zircons preserved evidence of a global cap of "protocrust" derived from remelting mantle rock that had remained stable for 600 million years, the study found.

Signs of global change

The new study found a similar transition to conditions resembling modern subduction in zircons from other locations around the world, dating to within about 200 million years of the South African zircons.

"We see evidence for a significant change on the Earth around 3.8 to 3.6 billion years ago and evolution toward plate tectonics is one clear possibility." Drabon said.

While not conclusive, the results suggest a global change may have begun, Drabon said, possibly starting and stopping in scattered locations before settling into the efficient global engine of constantly moving plates we see today.

Plate tectonics shapes Earth's atmosphere as well as its surface. Release of volcanic gasses and production of new silicate rock, which consumes large amounts carbon dioxide from the atmosphere, temper large temperature swings from too much or too little greenhouse gas.

"Without all of the recycling and new crust forming, we might be going back and forth between boiling hot and freezing cold," Drabon said. "It's kind of like a thermostat for the climate."

Plate tectonics has, so far, only been observed on Earth, and may be essential to making a planet livable, Drabon said, which makes the origins of plate motions of interest in research into the early development of life.

Read more at Science Daily

Dying stars' cocoons might explain fast blue optical transients

Ever since they were discovered in 2018, fast blue optical transients (FBOTs) have utterly surprised and completely confounded both observational and theoretical astrophysicists.

So hot that they glow blue, these mysterious objects are the brightest known optical phenomenon in the universe. But with only a few discovered so far, FBOTs' origins have remained elusive.

Now a Northwestern University astrophysics team presents a bold new explanation for the origin of these curious anomalies. Using a new model, the astrophysicists believe FBOTs could result from the actively cooling cocoons that surround jets launched by dying stars. It marks the first astrophysics model that is fully consistent with all observations related to FBOTs.

The research was published April 11 in the Monthly Notices of the Royal Astronomical Society.

As a massive star collapses, it can launch outflows of debris at rates near the speed of light. These outflows, or jets, collide into collapsing layers of the dying star to form a "cocoon" around the jet. The new model shows that as the jet pushes the cocoon outward -- away from the core of the collapsing star -- it cools, releasing heat as an observed FBOT emission.

"A jet starts deep inside of a star and then drills its way out to escape," said Northwestern's Ore Gottlieb, who led the study. "As the jet moves through the star, it forms an extended structure, known as the cocoon. The cocoon envelopes the jet, and it continues to do so even after the jet escapes the star, this cocoon escapes with the jet. When we calculated how much energy the cocoon has, it turned out to be as powerful as an FBOT."

Gottlieb is a Rothschild Fellow in Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA). He coauthored the paper with CIERA member Sasha Tchekovskoy, an assistant professor of physics and astronomy in Northwestern's Weinberg College of Arts and Sciences.

The hydrogen problem

FBOTs (pronounced F-bot) are a type of cosmic explosion initially detected in the optical wavelength. As their name implies, transients fade almost as quickly as they appear. FBOTs reach peak brightness within a matter of days and then quickly fade -- much faster than standard supernovae rise and decay.

After discovering FBOTs just eight years ago, astrophysicists wondered if the mysterious events were related to another transient class: gamma ray bursts (GRBs). The strongest and brightest explosions across all wavelengths, GRBs also are associated with dying stars. When a massive star exhausts its fuel and collapses into a black hole, it launches jets to produce a powerful gamma ray emission.

"The reason why we think GRBs and FBOTs might be related is because both are very fast -- moving at close to the speed of light -- and both are asymmetrically shaped, breaking the spherical shape of the star," Gottlieb said. "But there was a problem. Stars that produce GRBs lack hydrogen. We don't see any signs of hydrogen in GRBs, whereas in FBOTs, we see hydrogen everywhere. So, it could not be the same phenomenon."

Using their new model, Gottlieb and his coauthors think they might have found an answer to this problem. Hydrogen-rich stars tend to house hydrogen in their outermost layer -- a layer too thick for a jet to penetrate.

"Basically, the star would be too massive for the jet to pierce through," Gottlieb said. "So the jet will never make it out of the star, and that's why it fails to produce a GRB. However, in these stars, the dying jet transfers all its energy to the cocoon, which is the only component to escape the star. The cocoon will emit FBOT emissions, which will include hydrogen. This is another area where our model is fully consistent with all FBOT observations."

Putting the picture together

Although FBOTs glow bright in optical wavelengths, they also emit radio waves and X-rays. Gottlieb's model explains these too.

When the cocoon interacts with the dense gas surrounding the star, this interaction heats up stellar material to release a radio emission. And when the cocoon expands far enough away from the black hole (formed from the collapsed star), X-rays can leak out from the black hole. The X-rays join radio and optical light to form a full picture of the FBOT event.

While Gottlieb is encouraged by his team's findings, he says more observations and models are needed before we can definitively understand FBOTs' mysterious origins.

"This is a new class of transients, and we know so little about them," Gottlieb said. "We need to detect more of them earlier in their evolution before we can fully understand these explosions. But our model is able to draw a line among supernovae, GRBs and FBOTs, which I think is very elegant."

"This study paves the way for more advanced simulations of FBOTs," Tchekovskoy said. "This next-generation model will allow us to directly connect the physics of the central black hole to the observables, enabling us to reveal otherwise hidden physics of the FBOT central engine."

Read more at Science Daily

Scientists resurrect ancient enzymes to improve photosynthesis

A Cornell University study describes a breakthrough in the quest to improve photosynthesis in certain crops, a step toward adapting plants to rapid climate changes and increasing yields to feed a projected 9 billion people by 2050.

The study, "Improving the Efficiency of Rubisco by Resurrecting Its Ancestors in the Family Solanaceae," published April 15 in Science Advances. The senior author is Maureen Hanson, the Liberty Hyde Bailey Professor of Plant Molecular Biology in the College of Agriculture and Life Sciences. First author Myat Lin is a postdoctoral research associate in Hanson's lab.

The authors developed a computational technique to predict favorable gene sequences that make Rubisco, a key plant enzyme for photosynthesis. The technique allowed the scientists to identify promising candidate enzymes that could be engineered into modern crops and, ultimately, make photosynthesis more efficient and increase crop yields.

Their method relied on evolutionary history, where the researchers predicted Rubisco genes from 20-30 million years ago, when Earth's carbon dioxide (CO2) levels were higher than they are today and the Rubisco enzymes in plants were adapted to those levels.

By resurrecting ancient Rubisco, early results show promise for developing faster, more efficient Rubisco enzymes to incorporate into crops and help them adapt to hot, dry future conditions, as human activities are increasing heat-trapping CO2 gas concentrations in Earth's atmosphere.

The study describes predictions of 98 Rubisco enzymes at key moments in the evolutionary history of plants in the Solanaceae family, which include tomato, pepper, potato, eggplant and tobacco. Researchers use tobacco as the experimental model for their studies of Rubisco.

"We were able to identify predicted ancestral enzymes that do have superior qualities compared to current-day enzymes," Hanson said. Lin developed the new technique for identifying predicted ancient Rubisco enzymes.

Scientists have known that they can increase crop yields by accelerating photosynthesis, where plants convert CO2, water and light into oxygen and sugars that plants use for energy and for building new tissues.

For many years, researchers have focused on Rubisco, a slow enzyme that pulls (or fixes) carbon from CO2 to create sugars. Aside from being slow, Rubisco also sometimes catalyzes a reaction with oxygen in the air; by so doing, it creates a toxic byproduct, wastes energy and makes photosynthesis inefficient.

Hanson's lab had previously tried to use Rubisco from cyanobacteria (blue-green algae), which is faster but also reacts readily with oxygen, forcing the researchers to try to create micro-compartments to protect the enzyme from oxygen, with mixed results. Other researchers have tried to engineer more optimal Rubisco by making changes in the enzyme's amino acids, though little was known about which changes would lead to desired results.

In this study, Lin reconstructed a phylogeny -- a tree-like diagram showing evolutionary relatedness among groups of organisms -- of Rubisco, using Solanaceae plants.

"By getting a lot of [genetic] sequences of Rubisco in existing plants, a phylogenetic tree could be constructed to figure out which Rubiscos likely existed 20 to 30 million years ago," Hanson said.

The advantage of identifying potential ancient Rubisco sequences is that carbon dioxide levels were possibly as high as 500 to 800 parts per million (ppm) in the atmosphere 25 million to 50 million years ago. Today, heat-trapping CO2 levels are rising sharply due to many human activities, with current measurements at around 420 ppm, after staying relatively constant under 300 ppm for hundreds of millennia until the 1950s.

Lin, Hanson and colleagues then used an experimental system developed for tobacco in Hanson's lab, and described in a 2020 Nature Plants paper, which employs E. coli bacteria to test in a single day the efficacy of different versions of Rubisco. Similar tests done in plants take months to verify.

The team found that ancient Rubisco enzymes predicted from modern-day Solanaceae plants showed real promise for being more efficient.

"For the next step, we want to replace the genes for the existing Rubisco enzyme in tobacco with these ancestral sequences using CRISPR [gene-editing] technology, and then measure how it affects the production of biomass," Hanson said. "We certainly hope that our experiments will show that by adapting Rubisco to present day conditions, we will have plants that will give greater yields."

Read more at Science Daily

Pacific Northwest wildfires alter air pollution patterns across North America

Increasingly large and intense wildfires in the Pacific Northwest are altering the seasonal pattern of air pollution and causing a spike in unhealthy pollutants in August, new research finds. The smoke is undermining clean air gains, posing potential risks to the health of millions of people, according to the study.

The research, led by scientists at the National Center for Atmospheric Research (NCAR), found that levels of carbon monoxide -- a gas that indicates the presence of other air pollutants -- have increased sharply as wildfires spread in August. Carbon monoxide levels are normally lower in the summer because of chemical reactions in the atmosphere related to changes in sunlight, and the finding that their levels have jumped indicates the extent of the smoke's impacts.

"Wildfire emissions have increased so substantially that they're changing the annual pattern of air quality across North America," said NCAR scientist Rebecca Buchholz, the lead author. "It's quite clear that there is a new peak of air pollution in August that didn't used to exist."

Although carbon monoxide generally is not a significant health concern outdoors, the gas indicates the presence of more harmful pollutants, including aerosols (airborne particulates) and ground-level ozone that tends to form on hot summer days.

The research team used satellite-based observations of atmospheric chemistry and global inventories of fires to track wildfire emissions during most of the past two decades, as well as computer modeling to analyze the potential impacts of the smoke. They focused on three North American regions: the Pacific Northwest, the central United States, and the Northeast.

Buchholz said the findings were particularly striking because carbon monoxide levels have been otherwise decreasing, both globally and across North America, due to improvements in pollution-control technologies.

The study was published this week in Nature Communications. The research was funded in part by the U.S. National Science Foundation, NCAR's sponsor. The paper was co-authored by researchers from the University of Colorado, Boulder; Columbia University; NASA; Tsinghua University; and Colorado State University.

Increasing impacts on air pollution

Wildfires have been increasing in the Pacific Northwest and other regions of North America, due to a combination of climate change, increased development, and land use policies. The fires are becoming a larger factor in air pollution, especially as emissions from human activities are diminishing because of more efficient combustion processes in motor vehicles and industrial facilities.

To analyze the impacts of fires, Buchholz and her collaborators used data from two instruments on the NASA Terra satellite: MOPITT (Measurements of Pollution in the Troposphere), which has tracked carbon monoxide continually since 2002; and MODIS (Moderate Resolution Imaging Spectrometer), which detects fires and provides information on aerosols. They also studied four inventories of wildfire emissions, which rely on MODIS data.

The scientists focused on the period from 2002, the beginning of a consistent and long-term record of MOPPIT data, to 2018, the last year for which complete observations were available at the time when they began their study.

The results showed an increase in carbon monoxide levels across North America in August, which corresponded with the peak burning season of the Pacific Northwest. The trend was especially pronounced from 2012 to 2018, when the Pacific Northwest fire season became much more active, according to the emissions inventories. Data from the MODIS instrument revealed that aerosols also showed an upward trend in August.

To determine whether the higher pollution levels were caused by the fires, the scientists eliminated other potential emission sources. They found that carbon monoxide levels upwind of the Pacific Northwest, over the Pacific Ocean, were much lower in August -- a sign that the pollution was not blowing in from Asia. They also found that fire season in the central U.S. and the Northeast did not coincide with the August increase in pollution, which meant that local fires in those regions were not responsible. In addition, they studied a pair of fossil fuel emission inventories, which showed that carbon monoxide emissions from human activities did not increase in any of the three study regions from 2012 to 2018.

"Multiple lines of evidence point to the worsening wildfires in the Pacific Northwest as the cause of degraded air quality," Buchholz said. "It's particularly unfortunate that these fires are undermining the gains that society has made in reducing pollution overall."

Risks to human health

The findings have implications for human health because wildfire smoke has been linked to significant respiratory problems, and it may also affect the cardiovascular system and worsen pregnancy outcomes.

Buchholz and her co-authors used an NCAR-based computer model, the Community Atmosphere Model with a chemistry component, to simulate the movement of emissions from the Pacific Northwest fires and their impact on carbon monoxide, ozone, and fine particulate matter. They ran the simulations on the Cheyenne supercomputer at the NCAR-Wyoming Supercomputing Center. The results showed the pollutants could affect more than 130 million people, including about 34 million in the Pacific Northwest, 23 million in the Central U.S., and 72 million in the Northeast.

Although the study did not delve deeply into the health implications of the emissions, the authors looked at respiratory death rates in Colorado for the month of August from 2002 to 2011, compared with the same month in 2012 to 2018. They chose Colorado, located in the central U.S. region of the study, because respiratory death rates in the state were readily obtainable.

They found that Colorado respiratory deaths in August increased significantly during the 2012-2018 period, when fires in the Pacific Northwest -- but not in Colorado -- produced more emissions in August.

Read more at Science Daily

Pterosaur discovery solves ancient feather mystery

An international team of palaeontologists has discovered remarkable new evidence that pterosaurs, the flying relatives of dinosaurs, were able to control the colour of their feathers using melanin pigments.

The study, published in the journal Nature, was led by University College Cork (UCC) palaeontologists Dr Aude Cincotta and Prof. Maria McNamara and Dr Pascal Godefroit from the Royal Belgian Institute of Natural Sciences, with an international team of scientists from Brazil and Belgium.

The new study is based on analyses of a new 115 million year old fossilized headcrest of the pterosaur Tupandactylus imperator from north-eastern Brazil. Pterosaurs lived side by side with dinosaurs, 230 to 66 million years ago.

This species of pterosaur is famous for its bizarre huge headcrest. The team discovered that the bottom of the crest had a fuzzy rim of feathers, with short wiry hair-like feathers and fluffy branched feathers.

"We didn't expect to see this at all," said Dr Cincotta. "For decades palaeontologists have argued about whether pterosaurs had feathers. The feathers in our specimen close off that debate for good as they are very clearly branched all the way along their length, just like birds today."

The team then studied the feathers with high-powered electron microscopes and found preserved melanosomes -- granules of the pigment melanin. Unexpectedly, the new study shows that the melanosomes in different feather types have different shapes.

"In birds today, feather colour is strongly linked to melanosome shape." said Prof. McNamara. "Since the pterosaur feather types had different melanosome shapes, these animals must have had the genetic machinery to control the colours of their feathers. This feature is essential for colour patterning and shows that coloration was a critical feature of even the very earliest feathers."

Read more at Science Daily