Physicists began using supercomputers to obtain solutions to this famously hard problem back in the 1960s. In 2000, with no solutions in sight, Kip Thorne, 2018 Nobel Laureate and one of the designers of LIGO, famously bet that there would be an observation of gravitational waves before a numerical solution was reached.

He lost that bet when, in 2005, Carlos Lousto, then at The University of Texas at Brownsville, and his team generated a solution using the Lonestar supercomputer at the Texas Advanced Computing Center. (Concurrently, groups at NASA and Caltech derived independent solutions.)

In 2015, when the Laser Interferometer Gravitational-Wave Observatory (LIGO) first observed such waves, Lousto was in shock.

“It took us two weeks to realize this was really from nature and not from inputting our simulation as a test,” said Lousto, now a professor of mathematics at Rochester Institute of Technology (RIT). “The comparison with our simulations was so obvious. You could see with your bare eyes that it was the merger of two black holes.”

Lousto is back again with a new numerical relativity milestone, this time simulating merging black holes where the ratio of the mass of the larger black hole to the smaller one is 128 to 1 — a scientific problem at the very limit of what is computational possible. His secret weapon: the Frontera supercomputer at TACC, the eighth most powerful supercomputer in the world and the fastest at any university.

His research with collaborator James Healy, supported by the National Science Foundation (NSF), was published in Physical Review Letters this week. It may require decades to confirm the results experimentally, but nonetheless it serves as a computational achievement that will help drive the field of astrophysics forward.

“Modeling pairs of black holes with very different masses is very computational demanding because of the need to maintain accuracy in a wide range of grid resolutions,” said Pedro Marronetti, program director for gravitational physics at NSF. “The RIT group has performed the world’s most advanced simulations in this area, and each of them takes us closer to understanding observations that gravitational-wave detectors will provide in the near future.”

LIGO is only able to detect gravitational waves caused by small and intermediate mass black holes of roughly equal size. It will take observatories 100 times more sensitive to detect the type of mergers Lousto and Healy have modeled. Their findings show not only what the gravitational waves caused by a 128:1 merger would look like to an observer on Earth, but also characteristics of the ultimate merged black hole including its final mass, spin, and recoil velocity. These led to some surprises.

“These merged black holes can have speeds much larger than previously known,” Lousto said. “They can travel at 5,000 kilometers per second. They kick out from a galaxy and wander around the universe. That’s another interesting prediction.”

The researchers also computed the gravitational waveforms — the signal that would be perceived near Earth — for such mergers, including their peak frequency, amplitude, and luminosity. Comparing those values with predictions from existing scientific models, their simulations were within 2 percent of the expected results.

Previously, the largest mass ratio that had ever been solved with high-precision was 16 to 1 — eight times less extreme than Lousto’s simulation. The challenge of simulating larger mass ratios is that it requires resolving the dynamics of the interacting systems at additional scales.

Like computer models in many fields, Lousto uses a method called adaptive mesh refinement to get precise models of the dynamics of the interacting black holes. It involves putting the black holes, the space between them, and the distant observer (us) on a grid or mesh, and refining the areas of the mesh with greater detail where it is needed.

Lousto’s team approached the problem with a methodology that he compares to Zeno’s first paradox. By halving and halving the mass ratio while adding internal grid refinement levels, they were able to go from 32:1 black hole mass ratios to 128:1 binary systems that undergo 13 orbits before merger. On Frontera, it required seven months of constant computation.

“Frontera was the perfect tool for the job,” Lousto said. “Our problem requires high performance processors, communication, and memory, and Frontera has all three.”

The simulation isn’t the end of the road. Black holes can have a variety of spins and configurations, which impact the amplitude and frequency of the gravitational waves their merger produces. Lousto would like to solve the equations 11 more times to get a good first range of possible “templates” to compare with future detections.

The results will help the designers of future Earth- and space-based gravitational wave detectors plan their instruments. These include advanced, third generation ground based gravitational wave detectors and the Laser Interferometer Space Antenna (LISA), which is targeted for launch in the mid-2030s.

The research may also help answer fundamental mysteries about black holes, such as how some can grow so big — millions of times the mass of the Sun.

“Supercomputers help us answer these questions,” Lousto said. “And the problems inspire new research and pass the torch to the next generation of students.”

The study was published in the journal Acta Palaeontologica Polonica.

In order to study the appearance of dinosaurs more closely, researchers today rely on a large number of skeletons in so-called bone beds, which are places where the animals sank into the mud in large numbers during their lifetime. However, juvenile animals had hardly been found in these until now. Researchers described fossils of still juvenile plateosaurs for the first time just a few years ago, but these were already almost as large as the adults. One possible reason: “The smaller individuals probably did not sink into the mud quite as easily and are therefore underrepresented at the bone beds,” suspects study leader Prof. Martin Sander of the University of Bonn.

He and his team used comparative anatomy to examine the new skeleton, which was immediately remarkable because of its small size. “Based on the length of the vertebrae, we estimate the total length of the individual to be about 7.5 feet (2.3 meters), with a weight of about 90 to 130 lbs. (40 to 60 kilograms),” explains Darius Nau, who was allowed to examine the find for his bachelor’s thesis. For comparison: Adult Plateosaurus specimens reached body lengths of 16 to 33 feet (five to ten meters) and could weigh more than four tons. Because of its small size alone, it was obvious to assume that “Fabian” was a juvenile animal. This assumption was confirmed by the fact that the bone sutures of the spinal column had not yet closed. Background: Similar to skull sutures in human babies, bone sutures only fuse over the course of life.

Young and old resembled each other anatomically and in their body proportions

Researchers found that the young dinosaur resembled its older relatives both in anatomical details, such as the pattern of the laminae on the vertebrae (bony lamellae connecting parts of the vertebrae, which are important anatomical features in many dinosaurs), and in the rough proportions of its body. “The hands and neck of the juveniles may be a little longer, the arm bones a little shorter and slimmer. But overall, the variations are relatively small compared to the variation within the species overall and also compared to other dinosaur species,” stresses Nau. The juveniles of the related Mussaurus for instance were still quadrupeds after hatching, but the adults were bipeds.

“The fact that the Plateosaurus juvenile already looked so similar to the adults is all the more remarkable considering that they were ten times heavier,” emphasizes paleontologist Dr. Jens Lallensack from the University of Bonn. It is however conceivable that the morphological development differed greatly from animal to animal, depending on the climatic conditions or the availability of food. Such differences are still seen in reptiles today.

The well-known descendants of Plateosaurus, the sauropods, are the subject of a current exhibition at the Zoological Research Museum Alexander Koenig in Bonn. The largest Plateosaurus skeleton ever found can be seen there.

Funding

The study received financial support for the excavation and preparation of the skeleton from the municipality of Frick and the Canton of Argonia (Swisslos-Fonds) of Switzerland.

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Down syndrome, the most common congenital disease in human genetics, has seen dramatic increases in longevity with advances in modern medicine. Unfortunately, new problems associated with this increased longevity have emerged, such early Alzheimer’s, reduced vision, and muscle weakness. However, unlike the nervous system, the vascular system in Down syndrome patients is very resistant to aging pathologies like solid cancers (as opposed to blood cancers such as leukemia), atherosclerosis, hypertension, and Kawasaki disease — a systemic vasculitis that some researchers say has a connection to SARS-CoV-2, the virus that causes COVID-19. It has therefore become important to conduct comprehensive genomic and pathological analyses, including secondary analyses of gene expression on Down syndrome chromosomes and changes due to different chromosome numbers, to determine its cause.

Down syndrome occurs when there is an extra chromosome 21 instead of the usual two. DSCR-1 is located on chromosome 21 and suppresses signals related to angiogenesis. A research group based in Kumamoto University (Japan) crossed hypercholesterolemia (ApoE-deficient) mice with those that highly expressed DSCR-1 and those that were DSCR-1-deficient to analyze the effects of aging. By examining the pathological signals produced by high cholesterol, they hoped to determine why corneal opacity (prominent in ApoE deficiency) is protected against by high DSCR-1 expression and exacerbated by DSCR-1 deficiency.

DSCR-1-deficient mice showed slight age-related corneal opacity, which was dramatically exacerbated when crossed with ApoE-deficient mice, and increased corneal inflammation. DSCR-1 protects postnatal homeostasis based on its inhibitory and antioxidant effects on the NFAT transcription factor — a major factor in the development of Down syndrome. DSCR-1 deficiency results in the abnormal activation of NFAT and the signal transduction function of SDF-1 and its receptor CXCR4, which has an angiogenic effect in peripheral blood vessels. This results in increased angiogenesis and lymphangiogenesis in the corneal area.

Researchers further clarified that DSCR-1 deficiency increases oxidized LDL cholesterol which, in turn, increases SDF-1 production in the endothelium and the production of the angiogenesis-promoting factor VEGF in infiltrating macrophages, thus resulting in pathological angiogenesis (and clouding) in the cornea. This condition was greatly alleviated by the administration of antibodies that neutralize the function of SDF-1.

“This study shows that, in addition to suppressing cancer growth and cytokine storms in sepsis, DSCR-1 may have a protective effect on pathological angiogenesis under high cholesterol conditions,” said study leader, Professor Takashi Minami. “We have also obtained data on NFAT/DSCR-1 signaling in patients with human corneal lesions, suggesting that drugs that block NFAT and its downstream SDF-1 function may be effective in protecting against age-related vascular disease.”

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The findings have been published in PNAS today and are important to efforts to develop broad-spectrum antiviral agents.

Professor Spencer Williams from the School of Chemistry at Bio21 said the research will help define a new ‘host-directed’ approach for treating infections by encapsulated viruses.

“One approach to treating viral infections is to make a new drug for each virus that comes along. But it is slow. An alternative and attractive approach is to make a drug against a human target that viruses need to replicate. The same drug can then be used and reused against many different viruses, even ones that have yet to emerge,” he said.

The findings result from work by Professor Gideon Davies and his UK team who clarified how the structure of the catalytic domain of human enzyme that trims sugar molecules from proteins during their production and Professor Williams’ and his Bio21 team, who developed a series of inhibitors to block the enzyme.

When tested in human cell lines, these inhibitors where shown to reduce infection in dengue viruses.

“Encapsulated viruses tend to harness the ‘glycosylation’ step of protein production, whereby glycans, or sugar molecules coat newly assembled proteins,” said Professor Williams.

“The sugar molecules provide instructions for proteins to fold into their correct 3D structure as well as transport instructions for the protein to be brought to its next destination within the cell. Glycosylation is facilitated by various enzymes that synthesize, trim, check and modify these sugar molecules.”

Our body’s cells contain around 42 million protein molecules. Protein production is a complex, multi-step process within the cell. Like products on a factory assembly-line, all proteins pass through ‘quality control’ check points where they are inspected before they are transported to their destination, to carry out their functions.

Viruses are not living organisms, but biological programs encoded in ribonucleic acid (RNA) or deoxyribonucleic acid (DNA).

They come to life when they enter a living cell and hijack the protein production systems. Viruses use the cell’s machinery to copy their DNA or RNA (in the case of SARS-CoV2, it’s RNA) and to produce the proteins they need to make copies of themselves.

The viral proteins produced in an infected cell undergo the ‘glycosylation’ and then pass through the quality control steps, which involves ‘trimming’ by an enzyme called ‘MANEA’.

“Trimming is a crucial quality control step and when it does not occur, client proteins are marked for degradation. MANEA represents a key target for broad spectrum drug development against encapsulated viruses, as inhibitors will trigger destruction of their proteins,” said Professor Davies.

Because viruses hijack this unusual biosynthetic pathway, it makes it a good potential drug target.

Researchers at the University of Warwick and University of Oxford studied the effect of the best inhibitors on viral replication.

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After developing the archive, the researchers used it to conduct three case studies that revealed surprising patterns and associations between climate change and the behavior of golden eagles, bears, caribou, moose and wolves. This work demonstrates both the feasibility and importance of studying animal ecology on extremely large scales. A research paper describing the archive and case studies appears in the November 6, 2020, issue of the journal Science.

“I’m really excited about how this work shows what you can learn from comparing data across populations on a very large scale,” said Elie Gurarie, an associate research scientist in UMD’s Department of Biology and a co-author of the paper. “I would say this is an early example of what we might call global animal movement ecology. We’re increasing our ability to monitor the pulse of animal populations across the Earth and ask big picture questions about what it means.”

Large-scale monitoring of things like sea-surface temperature and global forest cover have revealed important information about the response of Earth’s systems to climate change and human activity. But big-picture trends in animal behavior have been difficult to study, in part because animal ecology is not traditionally studied across landscapes that span entire regions of the globe, and also because the necessary data are collected by a variety of agencies and jurisdictions and are therefore neither standardized nor easily accessible.

To address these issues, Gurarie and his collaborators spent years building relationships with scientists from national, regional and First Nations governments and research groups throughout the Arctic to convey the benefits of sharing data in a global repository that they call the Arctic Animal Movement Archive (AAMA). Currently, the archive includes contributions from researchers from over 100 universities, government agencies and conservation groups across 17 countries.

The archive includes data from 201 terrestrial and marine animal tracking studies representing more than 8,000 animals between 1991 and the present. Using this data, Gurarie and members of his lab analyzed the movements of more than 900 female caribou from 2000 to 2017. They found that the iconic long-distance migrating caribou are giving birth earlier in the spring, roughly tracking rates of warming. But among the non-migratory mountain and lowland woodland caribou only the northern sub-populations are showing similar changes. While the drivers of these differences remain a mystery, understanding their behavior is critical to anticipating how they will respond as the Arctic continues to warm and many populations continue to decline.

“It’s tricky to predict how these trends might impact populations,” Gurarie said. “On the one hand, it can be better to give birth earlier, as it gives the calves more opportunity to grow during the summer season. On the other hand, giving birth too early may mean you literally don’t have time to reach the optimal calving grounds. The ability to look at biological processes, like birth, at such a large scale, across populations and subspecies and over millions of square kilometers, is unprecedented for a species in such a remote and harsh environment. These results reveal patterns that we would not have suspected, and point to further lines of inquiry about everything from caribou evolution to their ability to adapt to environmental changes moving forward.”

Data analysis tools Gurarie developed to study caribou were also used for another case study led by his collaborators.

In an analysis comparing movements of more than 100 golden eagles from 1993 to 2017, Scott LaPoint, a researcher from Columbia University who is now at Black Rock Forest Consortium, found that immature birds migrating north in the spring arrived earlier following mild winters, while adult birds did not. The timing shift for young birds varied in response to a large-scale climate cycle called the Pacific Decadal Oscillation, which is being affected by climate change. Such age-related behavior changes could only be seen through decades of movement data and may have implications for breeding success.

A third study by Peter Mahoney of the University of Washington looked at the movement speeds of bears, caribou, moose and wolves from 1998 to 2019. His study showed that species respond differently to seasonal temperatures and winter snow conditions. Those differences could influence species interactions, food competition and predator-prey dynamics.

The scientists expect that other researchers will continue to mine the AAMA for answers to pressing questions about whether and how animals are responding to a changing Arctic. Meanwhile, the resource continues to expand as more data comes in from currently tracked animals and more researchers add their studies.

“This work has given us a baseline to understand the large-scale picture so we can get a sense of how animals and environments are really interacting across species and across space as the environment changes,” Gurarie said.

Despite having lizardlike claws, scales and tails, albanerpetontids — mercifully called “albies” for short — were amphibians, not reptiles. Their lineage was distinct from today’s frogs, salamanders and caecilians and dates back at least 165 million years, dying out only about 2 million years ago.

Now, a set of 99-million-year-old fossils redefines these tiny animals as sit-and-wait predators that snatched prey with a projectile firing of their tongue — and not underground burrowers, as once thought. The fossils, one previously misidentified as an early chameleon, are the first albies discovered in modern-day Myanmar and the only known examples in amber.

They also represent a new genus and species: Yaksha perettii, named after treasure-guarding spirits known as yakshas in Hindu literature and Adolf Peretti, the discoverer of two of the fossils.

“This discovery adds a super-cool piece to the puzzle of this obscure group of weird little animals,” said study co-author Edward Stanley, director of the Florida Museum of Natural History’s Digital Discovery and Dissemination Laboratory. “Knowing they had this ballistic tongue gives us a whole new understanding of this entire lineage.”

A fortunate mistake

The discovery began with a bumble.

In 2016, Stanley and Juan Diego Daza, lead author of the Science study and assistant professor of biological sciences at Sam Houston State University, published a paper presenting a dozen rare amber fossil lizards — or so they thought. One juvenile specimen possessed a hodgepodge of bewildering characteristics, including a specialized tongue bone. After much debate and consultation with colleagues, the scientists finally labelled it an ancient chameleon, about 99 million years old, an estimate based on radiometric dating of crystals at the site where the fossil was found.

When she read the study, Susan Evans, professor of vertebrate morphology and paleontology at University College London and an albie expert, instantly recognized the puzzling specimen. It was no chameleon. She emailed Daza.

“I remember that as one of the worst days of my life,” he said.

But the paper also attracted the attention of an unexpected collaborator: Peretti, a gemologist who contacted Daza about another collection of amber fossil lizards from the same region of Myanmar. (Note: The mining and sale of Burmese amber are often entangled with human rights abuses. Peretti acquired the fossils legally from companies that follow a strict ethical code. More details appear in an ethics statement at the end of this story).

Per Daza’s recommendation, Peretti sent the collection to the University of Texas at Austin for CT scanning, a way of clarifying what lies inside. As Daza began cleaning up the scans, one fossil in particular caught his eye — the complete skull of an adult albie.

Most fossil albies are crushed flat or a jumble of bones in disarray. In 1995, Evans published the first description of a complete specimen, excavated in Spain, but “it was very much roadkill,” she said. Even amber fossils suffer degradation, and soft tissues can mineralize, becoming difficult to work with.

This specimen, however, was not only three-dimensional, “it was in mint condition,” Stanley said. “Everything was where it was supposed to be. There was even some soft tissue,” including the tongue pad and parts of the jaw muscles and eyelids.

It was also the adult counterpart to the juvenile albie that had been mistaken for a chameleon.

When Daza sent the scan to Evans, she was dazzled by its rich detail.

“All my Christmases have come at once!” she wrote back.

‘Weird and wonderful’

Once classified as salamanders, albies’ stippled, reinforced skulls led many scientists to hypothesize they were diggers. No one imagined them as having chameleonlike lifestyles, Stanley said. But, he added, “if you’re going to misidentify an albie as any kind of lizard, a chameleon is absolutely what you would land on.”

Even though one is an amphibian and the other a reptile, they share several features, including claws, scales, massive eye sockets and — we now know — a projectile feeding mechanism.

The chameleon tongue is one of the fastest muscles in the animal kingdom and can rocket from 0 to 60 mph in a hundredth of a second in some species. It gets its speed from a specialized accelerator muscle that stores energy by contracting and then launching the elastic tongue with a recoil effect. If the earliest albies also had ballistic tongues, the feature is much older than the first chameleons, which may have appeared 120 million years ago. Fossil evidence indicates albies are at least 165 million years old, though Evans said their lineage must be much more ancient, originating more than 250 million years ago.

While armed with a rapid-fire tongue, Y. perettii was tiny: Based on the fossil skull, Daza estimates the adult was about 2 inches long, not including the tail. The juvenile was a quarter that size.

“We envision this as a stocky little thing scampering in the leaf litter, well hidden, but occasionally coming out for a fly, throwing out its tongue and grabbing it,” Evans said.

The revelation that albies had projectile tongues helps explain some of their “weird and wonderful” features, such as unusual jaw and neck joints and large, forward-looking eyes, a common characteristic of predators, she said. They may also have breathed through their skin, as salamanders do.

Even though the specimens are remarkably preserved, Stanley said CT scanning was essential to the analysis, revealing fine-scale features obscured in the cloudy amber.

“They only come to life with CT scanning,” he said. “Digital technology is really key with this amber material.”

Digitization also enabled the researchers, scattered around the world and hunkered down during COVID-19 quarantines, to collaboratively analyze and describe the specimens — and then make the same material digitally available to others.

How are albanerpetontids related to other amphibians?

Despite the level of preservation and completeness of the Y. perettii specimens, albies’ exact place in the amphibian family tree remains a mystery. The researchers coded the specimens’ physical characteristics and ran them through four models of amphibian relationships with no clear results. The animals’ unusual combination of features is likely to blame, Evans said.

“In theory, albies could give us a clue as to what the ancestors of modern amphibians looked like,” she said. “Unfortunately, they’re so specialized and so weird in their own way that they’re not helping us all that much.”

But Y. perettii does put albies on a new part of the map. Northwest Myanmar was likely an island 99 million years ago and possibly a remnant from Gondwana, the ancient southern continental landmass. With two exceptions in Morocco, all other fossil albies have been found in North America, Europe and East Asia, which formerly formed a northern continental landmass. Daza said Y. perettii may have rafted to the island from mainland Asia or could represent a new southern record for the group.

We just missed them

With such a wide distribution, why did albies vanish into extinction while frogs, salamanders and caecilians still exist today?

We don’t know. Albies almost survived to the present, fading out about 2 million years ago, possibly late enough to have crossed paths with our earliest hominid relatives, Evans said.

“We only just missed them. I keep hoping they’re still alive somewhere.”