To better characterize “The Great Dying,” the team sought to understand why communities didn’t recover as quickly as other mass extinctions. The main reason was that the end-Permian crisis was much more severe than any other mass extinction, wiping out 19 out of every 20 species. With survival of only 5% of species, ecosystems had been destroyed, and this meant that ecological communities had to reassemble from scratch.

To investigate, lead author and Academy researcher Yuangeng Huang, now at the China University of Geosciences, Wuhan, reconstructed food webs for a series of 14 life assemblages spanning the Permian and Triassic periods. These assemblages, sampled from north China, offered a snapshot of how a single region on Earth responded to the crises. “By studying the fossils and evidence from their teeth, stomach contents, and excrement, I was able to identify who ate whom,” says Huang. “It’s important to build an accurate food web if we want to understand these ancient ecosystems.”

The food webs are made up of plants, molluscs, and insects living in ponds and rivers, as well as the fishes, amphibians, and reptiles that eat them. The reptiles range in size from that of modern lizards to half-ton herbivores with tiny heads, massive barrel-like bodies, and a protective covering of thick bony scales. Sabre-toothed gorgonopsians also roamed, some as large and powerful as lions and with long canine teeth for piercing thick skins. When these animals died out during the end-Permian mass extinction, nothing took their place, leaving unbalanced ecosystems for ten million years. Then, the first dinosaurs and mammals began to evolve in the Triassic. The first dinosaurs were small — bipedal insect-eaters about one meter long — but they soon became larger and diversified as flesh- and plant-eaters.

“Yuangeng Huang spent a year in my lab,” says Peter Roopnarine, Academy Curator of Geology. “He applied ecological modelling methods that allow us to look at ancient food webs and determine how stable or unstable they are. Essentially, the model disrupts the food web, knocking out species and testing for overall stability.”

“We found that the end-Permian event was exceptional in two ways,” says Professor Mike Benton from the University of Bristol. “First, the collapse in diversity was much more severe, whereas in the other two mass extinctions there had been low-stability ecosystems before the final collapse. And second, it took a very long time for ecosystems to recover, maybe 10 million years or more, whereas recovery was rapid after the other two crises.”

Ultimately, characterizing communities — especially those that recovered successfully — provides valuable insights into how modern species might fare as humans push the planet to the brink.

“This is an amazing new result,” says Professor Zhong-Qiang Chen of the China University of Geosciences, Wuhan. “Until now, we could describe the food webs, but we couldn’t test their stability. The combination of great new data from long rock sections in North China with cutting-edge computational methods allows us to get inside these ancient examples in the same way we can study food webs in the modern world.”

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In a study published in Nano Letters, physicists from Michigan Technological University explore alternative materials to improve capacity and shrink the size of digital data storage technologies. Ranjit Pati, professor of physics at Michigan Tech, led the study and explains the physics behind his team’s new nanowire design.

“Thanks to a property called spin, electrons behave like tiny magnets,” Pati said. “Similar to how a bar magnet’s magnetization is dipolar, pointing from south to north, the electrons in a material have magnetic dipole moment vectors that describe the material’s magnetization.”

When these vectors are in random orientation, the material is nonmagnetic. When they are parallel to each other, it’s called ferromagnetism and antiparallel alignments are antiferromagnetism. Current data storage technology is based on ferromagnetic materials, where the data are stored in small ferromagnetic domains. This is why a strong enough magnet can mess up a mobile phone or other electronic storage.

Depending on the direction of magnetization (whether pointing up or down), data are recorded as bits (either a 1 or 0) in ferromagnetic domains. However, there are two bottlenecks, and both hinge on proximity. First, bring an external magnet too close, and its magnetic field could alter the direction of magnetic moments in the domain and damage the storage device. And, second, the domains each have a magnetic field of their own, so they can’t be too close to each other either. The challenge with smaller, more flexible, more versatile electronics is that they demand devices that make it harder to keep ferromagnetic domains safely apart.

“Ultrahigh-density data packing would be a daunting task with ferromagnetic memory domains,” Pati said. “Antiferromagnetic materials, on the other hand, are free from these issues.”

On their own antiferromagnetic materials aren’t great for electronic devices, but they’re not influenced by outside magnetic fields. This ability to resist magnetic manipulation started getting more attention from the research community and Pati’s team used a predictive quantum many-body theory that considers electron-electron interactions. The team found that chromium-doped nanowires with a germanium core and silicon shell can be an antiferromagnetic semiconductor.

Several research groups have recently demonstrated manipulation of individual magnetic states in antiferromagnetic materials using electrical current and lasers. They observed spin dynamics in the terahertz frequency — much faster than the frequency used in our current data storage devices. This observation has opened up a plethora of research interests in antiferromagnetism and could lead to faster, higher-capacity data storage.

“In our recent work, we have successfully harnessed the intriguing features of an antiferromagnet into a low-dimensional, complementary metal-oxide compatible semiconductor (CMOS) nanowire without destroying the semiconducting property of the nanowire,” Pati said. “This opens up possibilities for smaller and smarter electronics with higher capacity data storage and manipulation.”

Pati adds that the most exciting part of the research for his team was uncovering the mechanism that dictates antiferromagnetism. The mechanism is called superexchange and it controls the spin of electrons and the antiparallel alignment that makes them antiferromagnetic. In the team’s nanowire, germanium electrons act as a go-between, an exchanger, between unconnected chromium atoms.

“The interaction between the magnetic states of the chromium atoms is mediated by the intermediate atoms they are bonded to. It is a cooperative magnetic phenomenon,” Pati said. “In a simple way, let us say there are two people A and B: They are far apart and cannot communicate directly. But A has a friend C and B has a friend D. C and D are close friends. So, A and B can interact indirectly through C and D.”

Better understanding how electrons communicate between atomic friends enables more experiments to test the potential of materials like chromium-doped nanowires. Better understanding the germanium-silicon nanowire material’s antiferromagnetic nature is what boosts potential for smaller, smarter, higher capacity electronics.

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Materials provided by Michigan Technological University. Original written by Allison Mills. Note: Content may be edited for style and length.

The researchers used molecular genetics to differentiate among corals that look nearly identical and to understand which species best coped with thermal stress. Their research was published in the journal Ecology.

“Being able to recognize the differences among these coral species that cannot be identified in the field — which are known as ‘cryptic species’ — will help us understand new ways for how coral reefs maintain resilience in the face of disturbance,” said Associate Professor of Biological Science Scott Burgess, the paper’s lead author.

The researchers were studying the coral ecosystem at the island of Moorea in French Polynesia when a coral bleaching event struck in 2019.

Corals get their color from algae that live in their tissues and with which they have a symbiotic relationship. But when corals are stressed — by high water temperature, for example — algae leave the coral, which turns white, hence the term “bleaching.” Bleached corals are not dead, but they are more vulnerable and more likely to die.

Most of the coral at Moorea belong to the genus Pocillopora. During the event, the researchers saw that about 72 percent of the coral colonies from this genus bleached, and up to 42 percent died afterward.

At first, it seemed that the largest colonies were more likely to bleach, but when the scientists examined tissue samples from the coral, they found that colonies belonging to a certain genetic lineage, not coral size, was most important in determining the fate of the corals.

“Because Pocillopora species look so similar, they cannot be reliably identified in the field, which, in the past, has forced researchers to study them as a single group,” said Erika Johnston, a postdoctoral researcher in the Department of Biological Science and a co-author of the paper. “Molecular genetics allows us to reconstruct their evolutionary ancestry and are an essential step to species identification in this case.”

About 86 percent of the Pocillopora corals that died belonged to a group that shares a set of DNA variations, which is known as a haplotype and reflects their common evolutionary ancestry.

“The good news is that not all of the corals died from bleaching, and many species survived,” Burgess said. “The bad news is that the species that died is, as far as we are aware at the moment, endemic to that specific region. So on the one hand, we’re worried about losing an endemic species, but on the other hand, our results show how co-occurring cryptic species can contribute to coral resilience.”

It’s an ecological analogy to having a diverse financial portfolio, where a variety of investments decreases the likelihood of a complete loss.

“Having multiple species that perform a similar function for the reef ecosystem but differ in how they respond to disturbances should increase the chance that Pocillopora corals continue to perform their role in the system, even though the exact species may be shuffled around,” Burgess said.

Maintaining healthy ecological portfolios may be a better management option than attempting to restore a specific species.

“If we maintain the right type of diversity, nature in a way can pick the winners and losers,” Burgess said. “However, the worry for us scientists is that unless the leaders of governments and corporations take action to reduce CO2 emissions, ecological portfolios that can maintain coral reef resilience will be increasingly eroded under current and ongoing climate change. This is concerning because coral reef ecosystems provide economic, health, cultural and ecological goods and services that humans rely on.”

Future research will look into the composition of the algae that live inside the coral, the depth distributions of each cryptic coral species and the evolutionary relationships among the cryptic species.

Researchers from the Hong Kong University of Science and Technology, the Scripps Institution of Oceanography and California State University, Northridge contributed to this study.

This work was conducted as part of a National Science Foundation grant awarded to Burgess.

The team of engineers succeeded in measuring the precise origin of the sound generated by the flapping wings of a flying animal for the first time. The hummingbird’s hum originates from the pressure difference between the topside and underside of the wings, which changes both in magnitude and orientation as the wings flap back and forth. These pressure differences over the wing are essential, because they furnish the net aerodynamic force that enables the hummingbird bird to liftoff and hover.

Unlike other species of birds, a hummingbird wing generates a strong upward aerodynamic force during both the downward and upward wing stroke, so twice per wingbeat. Whereas both pressure differences due to the lift and drag force acting on the wing contribute, it turns out that the upward lifting pressure difference is the primary source of the hum.

The difference between whining, humming, buzzing and wooshing

Professor David Lentink of Stanford University: “This is the reason why birds and insects make different sounds. Mosquitoes whine, bees buzz, hummingbirds hum, and larger birds ‘woosh’. Most birds are relatively quiet because they generate most of the lift only once during the wingbeat at the downstroke. Hummingbirds and insects are noisier because they do so twice per wingbeat.”

The researchers combined all measurements in a 3D acoustic model of bird and insect wings. The model not only provides biological insight into how animals generate sound with their flapping wings, it also predicts how the aerodynamic performance of a flapping wing gives the wing sound its volume and timbre. “The distinctive sound of the hummingbird is perceived as pleasant because of the many ‘overtones’ created by the varying aerodynamic forces on the wing. A hummingbird wing is similar to a beautifully tuned instrument,” Lentink explains with a smile.

High-tech sound camera

To arrive at their model, the scientists examined six Anna’s hummingbirds, the most common species around Stanford. One by one, they had the birds drink sugar water from a fake flower in a special flight chamber. Around the chamber, not visible to the bird, cameras, microphones and pressure sensors were set up to precisely record each wingbeat while hovering in front of the flower.

You can’t just go out and buy the equipment needed for this from an electronics store. CEO and researcher Rick Scholte of Sorama, a spin-off of TU Eindhoven: “To make the sound visible and be able to examine it in detail, we used sophisticated sound cameras developed by my company. The optical cameras are connected to a network of 2176 microphones for this purpose. Together they work a bit like a thermal camera that allows you to show a thermal image. We make the sound visible in a ‘heat map’, which enables us to see the 3D sound field in detail.”

New aerodynamic force sensors

To interpret the 3D sound images, it is essential to know what motion the bird’s wing is making at each sound measurement point. For that, Stanford’s twelve high-speed cameras came into play, capturing the exact wing movement frame-by-frame.

Lentink: “But that’s not end of story. We also needed to measure the aerodynamic forces the hummingbird’s wings generates in flight. We had to develop a new instrument for that.” During a follow-up experiment six highly sensitive pressure plates finally managed to record the lift and drag forces generated by the wings as they moved up and down, a first.

The terabytes of data then had to be synchronized. The researchers wanted to know exactly which wing position produced which sound and how this related to the pressure differences. Scholte: “Because light travels so much faster than sound, we had to calibrate each frame separately for both the cameras and the microphones, so that the sound recordings and the images would always correspond exactly.” Because the cameras, microphones and sensors were all in different locations in the room, the researchers also had to correct for that.

Algorithm as a composite artist

Once the wing location, the corresponding sound and the pressure differences are precisely aligned for each video frame, the researchers were confronted with the complexity of interpretating high volume data. The researchers tackled this challenge harnessing artificial intelligence, the research of TU/e PhD student, and co-first author, Patrick Wijnings.

Wijnings: “We developed an algorithm for this that can interpret a 3D acoustic field from the measurements, and this enabled us to determine the most probable sound field of the hummingbird. The solution to this so-called inverse problem resembles what a police facial composite artist does: using a few clues to make the most reliable drawing of the suspect. In this way, you avoid the possibility that a small distortion in the measurements changes the outcome.”

The researchers finally managed to condense all these results in a simple 3D acoustic model, borrowed from the world of airplanes and mathematically adapted to flapping wings. It predicts the sound that flapping wings radiate, not only the hum of the hummingbird, but also the woosh of other birds and bats, the buzzing and whining of insects and even the noise that robots with flapping wings generate.

Making drones quieter

Although it was not the focus of this study, the knowledge gained may also help improve aircraft and drone rotors as well as laptop and vacuum cleaner fans. The new insights and tools can help make engineered devices that generate complex forces like animals do quieter.

This is exactly what Sorama aims to do: “We make sound visible in order to make appliances quieter. Noise pollution is becoming an ever-greater problem. And a decibel meter alone is not going to solve that. You need to know where the sound comes from and how it is produced, in order to be able to eliminate it. That’s what our sound cameras are for. This hummingbird wing research gives us a completely new and very accurate model as a starting point, so we can do our work even better,” concludes Scholte.

Video: https://www.youtube.com/watch?v=CfFitC4D838&t=2s

Now, a new report by UCLA’s Center for Scholars and Storytellers assesses the values emphasized by television programs popular with tweens over each decade from 1967 to 2017, charting how 16 values have waxed and waned in importance during that 50-year span.

Among the key findings is that fame, after nearly 40 years of ranking near the bottom (it was 15th in 1967, 1987 and 1997), rose to become the No. 1 value in 2007, then dropped to sixth in importance in 2017.

Achievement — being very successful — was ranked first in 2017, with self-acceptance, image, popularity and being part of a community rounding out the top five.

The report, “The Rise and Fall of Fame: Tracking the Landscape of Values Portrayed on Television from 1967 to 2017”, evaluated two programs per decade (and four in 2017), from “The Andy Griffith Show” in 1967 and “Happy Days” in 1977 to “American Idol” and “Hannah Montana” in 2007 and “America’s Got Talent” and “Girl Meets World” in 2017.

Like fame, values such as community feeling and benevolence have also seen dramatic rises and falls over the past half-century, with their rankings typically echoing changes in the larger culture, the researchers found.

Being part of community, for instance, which ranked No. 1 in 1967, 1977 and 1997 (and No. 2 in 1987), plummeted to the 11th spot in 2007 — 10 spots below fame — before rising again to fifth in 2017. Likewise, being kind and helping others, the No. 2 value in 1967 and 1997, fell to the 12th spot in 2007. It is now ranked eighth.

“I believe that television reflects the culture, and this half-century of data shows that American culture has changed drastically,” said report author Yalda Uhls, founder and executive director of the Center for Scholars and Storytellers and an adjunct assistant professor of psychology. “Media plays an important role as young people are developing a concept of the social world outside of their immediate environment.”

The concepts children develop can also vary widely based on what types of programs they’re watching, according to the authors, who found a stark divergence between the values conveyed in reality shows — first evaluated in 2007 — and those of scripted fictional shows.

Values in reality TV vs. fictional programs

The most popular tween reality shows in 2017, based on Nielsen ratings, were “America’s Got Talent” and “American Ninja Warrior,” while the top two scripted shows were “Thundermans” and “Girl Meets World.” In the scripted shows, the top values conveyed were self-acceptance, benevolence and being part of a community. In contrast, the top values conveyed in reality shows were fame, image and self-centeredness.

Reality shows, created for a broad audience and watched frequently by tweens, often highlight competition and the importance of being No. 1 and include bullying, cheating and a winning-at-all-costs value system, the authors note.

“If tweens watch, admire and identify with people who mostly care about fame and winning, these values may become even more important in our culture,” said the report’s lead author, Agnes Varghese, a fellow of the center and a UC Riverside graduate student. “Reality television shows continued to reflect the same trend we saw in 2007, with self-focused values such as fame ranking highest.”

The authors recommend that parents help children understand that reality shows do not depict the experience of the average person and that fictional shows do not adequately depict the hard work and struggles associated with achieving fame.

TV values and the rise of social media

Uhls believes the explosive growth and popularity of social media platforms such as Facebook, launched in 2004, and YouTube, launched in 2005, may have influenced television content creators in the first decade of the 2000s to make fame-focused tween shows. Other research has shown that social media growth was accompanied by a rise in narcissism and a decrease in empathy among college students in the U.S., she notes.

“I don’t think this is a coincidence,” said Uhls, who was formerly a movie studio executive. “The growth of social media gives children access to an audience beyond the school grounds.”

By 2017, the social media landscape had expanded to include platforms like Snapchat and Instagram, and the access they provided to an ever-widening audience made popularity seem more easily attainable. For that reason, Uhls believes, achieving fame may have become less desirable and unique. In addition, the severe recession of 2007-09 may have shifted the culture away from self-focused values such as fame and getting rich.

Research conducted by UCLA distinguished professor of psychology Patricia Greenfield and colleagues has shown that society tends to become more community-focused in times of collective distress, Uhls noted.

Because children, particularly in their tween years, are forming a belief system that integrates the many messages about desirable future aspirations they receive from parents, school, peers and media, it is crucial to understand the role television plays in promoting values — both positive and negative, the researchers say.

The report draws on research, both published and unpublished, by Uhls, Greenfield and former UCLA graduate students Jill Giardino and Caroline Fung.

“These two neighborhoods are very similar in terms of vegetation cover, human population and density of households. One of the main differences is blight. One neighborhood has a lot of blight in the form of abandoned residences, empty lots and mismanaged waste, and the other neighborhood does not. It was the perfect set of conditions for addressing this question,” said Rebeca de Jesús Crespo, lead author and an assistant professor in LSU’s College of the Coast & Environment.

In recent years, the Old South neighborhood has been the focus of revitalization plans by multiple stakeholder groups. The researchers recommended that these blight reduction efforts continue for the benefit of public health.

“This is an area at high risk of these mosquito-borne diseases,” said Madison Harrison, co-author of the publication. “All that it takes for these diseases to spread is for the right vector to be infected with the pathogen and to bite humans at the right point of incubation of said pathogen.”

So far, Zika and dengue are not currently present in the state. However, Louisiana’s climate is ideal for these diseases to spread once introduced.

According to de Jesús Crespo, Harrison was an invaluable addition to the team. Currently, she is a public health master’s student at LSU Health New Orleans.

“In the College of the Coast & Environment, for almost every project that we do, we are integrated and interdisciplinary. We take a broad approach to doing research that is important for solving problems in real time. For this project, it was important to me to include Madison from LSU Health Sciences as well as community stakeholders who could provide their expertise and unique perspectives,” de Jesús Crespo said.

The researchers examined the prevalence of two container-breeding species of mosquitoes that are known to spread disease, the Asian tiger mosquito and the southern house mosquito (a carrier of West Nile virus). They inspected potential larvae habitats (such as discarded tires, discarded Styrofoam cups and snack bags, plant pots and water baths) in publicly accessible locations and calculated the percentage of those that contained larvae. Additionally, they placed adult mosquito traps around the perimeter of some private homes with the permission from the homeowner, in an abandoned house and in an empty lot with trash accumulation in the higher income neighborhood.

They found that the adult population of the southern house mosquito was fairly diffuse, but the lower income neighborhood had significantly higher numbers of Asian tiger mosquito (adults and larvae) and higher numbers of total mosquito larvae. This shows that the presence of discarded container habitats due to neglect provides more breeding grounds for disease-carrying mosquitoes, disproportionately affecting low-income groups.

“I think everybody can agree that urban blight is a problem we need to solve here in Baton Rouge. Mosquito risk is one of those factors that could impact human health and that adds another level of importance with that,” de Jesús Crespo said.

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Materials provided by Louisiana State University. Note: Content may be edited for style and length.