How does evolution impact ecological patterns? It helps smooth out the rough edges, says UConn Ecology and Evolutionary Biology Professor Mark Urban. Urban led an international team of researchers through a review of the history of ecological and evolutionary research to establish a framework to better understand evolution's impact on ecosystem patterns. The research is published as a perspective in the Proceeding of the National Academy of Sciences.
Urban says the project started years ago in the course of his field research when he encountered a trend that he had trouble explaining.
"Ever since I was a grad student I've been thinking about how evolution across landscapes happens, and then how it affects the ecology of those systems. At some point I was struggling to describe a pattern that I was seeing in the amphibian system I work in," he says.
Urban explains that historically, ecologists and evolutionary biologists have worked fairly isolated from one another. The reason is due to assumptions that evolution happens over time periods and distances that have little immediate impact on ecological systems. Ecologists and evolutionary biologists go to their own academic meetings and conferences and publish in their own journals, says Urban, and as a result, members of the fields rarely collaborate. However, Urban suspected the explanation for the puzzling pattern he was seeing relied on a merging of the disciplines.
Urban partnered with colleagues from across the globe, calling on experts from evolutionary biology and ecology, to tackle the question. The project involved an extensive review of the literature, a process that Urban says at times felt unending, yet quite fun. The process was also exciting because early on, the researchers began to notice patterns supporting their hypothesis that local adaptation alters spatial patterns.
Sean Giery, co-author and a former UConn post-doctoral researcher who's now an Eberly Research Fellow at Pennsylvania State University says, "Finding new evidence in old scientific papers was always rewarding. And collectively, these efforts show that the effects of evolution on how much communities and ecosystems vary across landscapes simply can't be overlooked."
The impetus for the undertaking, Urban says, came from a familiar figure: the salamander.
Salamander populations adapt to predators via different strategies -- from changes in body shape and size to the types and quantities of foods that they eat, which suggests a connection between evolution and ecology.
"In particular, I got excited by the evolution of foraging traits, because that could have a clear ecological impact," Urban says.
For example, Urban found that salamanders evolve to forage more in a pond with limited resources, and as a result they amplify the original ecological pattern of low resources by eating more of the already limited resources. In other cases, local adaptation of other traits dampens existing spatial patterns. Urban next turned to the existing literature to find out how general these patterns were, not just in salamanders, but in everything from bacteria to birds.
Based on a review of 500 studies, the authors found evolutionary adaptations at the local level can amplify, dampen, or even create new ecological patterns across landscapes. They identified 14 different mechanisms that affect the direction of evolution's impact, but overall the researchers found that evolution tended to dampen or smooth out variations.
"Evolution clearly plays an important role at these large scales, especially by reducing the effects of abiotic factors and biotic interactions that can limit the abundance and distribution of species. By dampening the impacts of these effects, evolution tends to reduce ecological heterogeneity across space," says Giery.
Adds Urban: "Our exhaustive review indicated that evolution usually dampens ecological spatial patterns, characterizing 85% of studies. Consequently, we do not observe the true spatial heterogeneity of nature because evolution has smoothed it out and hidden its rough edges. Evolution makes the world less ragged, which to me is a pretty cool take-home message."
An example of the smoothing can be seen again with salamanders, says Urban: "The salamanders that ate more also tended to dampen out the effect of the predator on the overall diversity of species across ponds. The prey salamander was eating different species than the predator, so in the end evolution actually maintains similar diversities of species across ponds even though, ecologically, the predator strongly decreases diversity."
Urban says these spatial patterns can be seen everywhere: "The interesting thing to me is that anyone can walk through nature and see these spatial patterns -- maybe different vegetation types. We see all of this spatial variation and we think of it as just being ecological or physical, just part of the environment and that's it. But that environmental spatial variation may be affected by the evolution of the organisms in the environment and that is what we are finding in experiments around world."
Giery says, "I'm pleased to have been a part of this project. And I'm excited to see how our efforts will influence the way people think about the role of evolution in ecological dynamics in space. This seems like one of those rare instances where a relatively simple idea is still transformative. Working on developing this idea has changed how I see and think about natural systems. I imagine our perspective will have the same impact on others."
Read more at Science Daily
Jul 9, 2020
15-foot-long skeleton of extinct dolphin suggests parallel evolution among whales
A report in the journal Current Biology on July 9 offers a detailed description of the first nearly complete skeleton of an extinct large dolphin, discovered in what is now South Carolina. The 15-foot-long dolphin (Ankylorhiza tiedemani comb. n.) lived during the Oligocene -- about 25 million years ago -- and was previously known only from a partial rostrum (snout) fossil.
The researchers say that multiple lines of evidence -- from the skull anatomy and teeth, to the flipper and vertebral column -- show that this large dolphin (a toothed whale in the group Odontoceti) was a top predator in the community in which it lived. They say that many features of the dolphin's postcranial skeleton also imply that modern baleen whales and modern toothed whales must have evolved similar features independently, driven by parallel evolution in the very similar aquatic habitats in which they lived.
"The degree to which baleen whales and dolphins independently arrive at the same overall swimming adaptations, rather than these traits evolving once in the common ancestor of both groups, surprised us," says Robert Boessenecker of the College of Charleston in Charleston, South Carolina. "Some examples include the narrowing of the tail stock, increase in the number of tail vertebrae, and shortening of the humerus (upper arm bone) in the flipper.
"This is not apparent in different lineages of seals and sea lions, for example, which evolved into different modes of swimming and have very different looking postcranial skeletons," he adds. "It's as if the addition of extra finger bones in the flipper and the locking of the elbow joint has forced both major groups of cetaceans down a similar evolutionary pathway in terms of locomotion."
Though first discovered in the 1880s from a fragmentary skull during phosphate dredging of the Wando River, the first skeleton of Ankylorhiza was discovered in the 1970s by then Charleston Museum Natural History curator Albert Sanders. The nearly complete skeleton described in the new study was found in the 1990s. A commercial paleontologist by the name of Mark Havenstein found it during construction of a housing subdivision in South Carolina. It was subsequently donated to the Mace Brown Museum of Natural History, to allow for its study.
While there's much more to learn from this fossil specimen, the current findings reveal that Ankylorhiza was an ecological specialist. The researchers say the species was "very clearly preying upon large-bodied prey like a killer whale."
Another intriguing aspect, according to the researchers, is that Ankylorhiza is the first echolocating whale to become an apex predator. When Ankylorhiza became extinct by about 23 million years ago, they explain, killer sperm whales and the shark-toothed dolphin Squalodon evolved and reoccupied the niche within 5 million years. After the last killer sperm whales died out about 5 million years ago, the niche was left open until the ice ages, with the evolution of killer whales about 1 or 2 million years ago.
"Whales and dolphins have a complicated and long evolutionary history, and at a glance, you may not get that impression from modern species," Boessenecker says. "The fossil record has really cracked open this long, winding evolutionary path, and fossils like Ankylorhiza help illuminate how this happened."
Boessenecker notes that more fossils of Ankylorhiza are awaiting study, including a second species and fossils of Ankylorhiza juveniles that can offer insight into the dolphin's growth. He says that there's still much to learn from fossilized dolphins and baleen whales from South Carolina.
Read more at Science Daily
The researchers say that multiple lines of evidence -- from the skull anatomy and teeth, to the flipper and vertebral column -- show that this large dolphin (a toothed whale in the group Odontoceti) was a top predator in the community in which it lived. They say that many features of the dolphin's postcranial skeleton also imply that modern baleen whales and modern toothed whales must have evolved similar features independently, driven by parallel evolution in the very similar aquatic habitats in which they lived.
"The degree to which baleen whales and dolphins independently arrive at the same overall swimming adaptations, rather than these traits evolving once in the common ancestor of both groups, surprised us," says Robert Boessenecker of the College of Charleston in Charleston, South Carolina. "Some examples include the narrowing of the tail stock, increase in the number of tail vertebrae, and shortening of the humerus (upper arm bone) in the flipper.
"This is not apparent in different lineages of seals and sea lions, for example, which evolved into different modes of swimming and have very different looking postcranial skeletons," he adds. "It's as if the addition of extra finger bones in the flipper and the locking of the elbow joint has forced both major groups of cetaceans down a similar evolutionary pathway in terms of locomotion."
Though first discovered in the 1880s from a fragmentary skull during phosphate dredging of the Wando River, the first skeleton of Ankylorhiza was discovered in the 1970s by then Charleston Museum Natural History curator Albert Sanders. The nearly complete skeleton described in the new study was found in the 1990s. A commercial paleontologist by the name of Mark Havenstein found it during construction of a housing subdivision in South Carolina. It was subsequently donated to the Mace Brown Museum of Natural History, to allow for its study.
While there's much more to learn from this fossil specimen, the current findings reveal that Ankylorhiza was an ecological specialist. The researchers say the species was "very clearly preying upon large-bodied prey like a killer whale."
Another intriguing aspect, according to the researchers, is that Ankylorhiza is the first echolocating whale to become an apex predator. When Ankylorhiza became extinct by about 23 million years ago, they explain, killer sperm whales and the shark-toothed dolphin Squalodon evolved and reoccupied the niche within 5 million years. After the last killer sperm whales died out about 5 million years ago, the niche was left open until the ice ages, with the evolution of killer whales about 1 or 2 million years ago.
"Whales and dolphins have a complicated and long evolutionary history, and at a glance, you may not get that impression from modern species," Boessenecker says. "The fossil record has really cracked open this long, winding evolutionary path, and fossils like Ankylorhiza help illuminate how this happened."
Boessenecker notes that more fossils of Ankylorhiza are awaiting study, including a second species and fossils of Ankylorhiza juveniles that can offer insight into the dolphin's growth. He says that there's still much to learn from fossilized dolphins and baleen whales from South Carolina.
Read more at Science Daily
'Bystander Effect' not exclusive to humans
A rat is less likely to help a trapped companion if it is with other rats that aren't helping, according to new research from the University of Chicago that showed the social psychological theory of the "bystander effect" in humans is present in these long-tailed rodents.
The study, titled "The Bystander Effect in Rats," also demonstrated that in the presence of other potential helper rats, rats are more, rather than less, likely to help. Whether helping is facilitated or suppressed depends on the circumstances rather than on personal temperament or morals, a finding with implications for human society. The research, published in the July 8 issue of Science Advances, builds off previous research on rat empathy.
In 2011, Peggy Mason, PhD, professor of neurobiology and senior author of the study, and her UChicago team of researchers found that rats consistently freed trapped companions, even saving a bit of chocolate for them, and this behavior was driven by a rat version of empathy. A subsequent study showed that rats treated with anti-anxiety medication are less likely to free a trapped peer because they do not feel its anxiety. In another study, researchers found that rats only freed trapped rat strains that they had previous social experience with.
The roots of the classic bystander effect date back to 1964, when Catherine "Kitty" Genovese was murdered in a crowded residential neighborhood in Queens, New York. An account published in the New York Times reported that 38 bystanders saw the murder but did not intervene. Though this story was later proven inaccurate, it inspired psychologists Bibb Latané and John Darley to investigate why so many people would fail to help.
The pair tested human subjects alone and in the presence of "confederate" bystanders -- people who were part of the research team and were instructed not to help -- as they confronted a variety of experimental scenarios with someone (an actor) in distress. Latané and Darley consistently observed that subjects were far less likely to help in the presence of non-helping confederates than they were when tested alone. This phenomenon, referred to as the bystander effect, is now a pillar in psychology, included in every introductory textbook and class. The mechanism for the classic bystander effect is thought to be a diffusion of responsibility whereby people reason that they need not act because others in a group will.
First author John Havlik was a UChicago undergraduate in Mason's laboratory, when the topic of the bystander effect came up during a lab meeting.
"My students had been bugging me to do this experiment for years," said Mason. "But it wasn't until John came along and would not let the idea go that we took the plunge."
Havlik, now a student at the Yale School of Medicine, spearheaded experiments to examine whether rats, which lack complex reasoning skills, would show a classical bystander effect.
The research team used their trapped rat paradigm in combination with rats that were made into "confederates" by administering an antianxiety drug that made them indifferent to another rat's distress, ensuring that they would not help. The team found that rats tested with confederates were less likely to help than those tested alone -- a bystander effect in rats. Digging deeper, they saw that the presence of confederates blocked reinforcement for helping.
"It's worse to have a non-responsive audience than to be alone," Mason said. "The rats try helping, but it's just not a rewarding experience because the other rats don't appear to care. It's as though the rat was saying to himself, 'I helped yesterday and no one cared. Not doing that again.' "
Mason and her team then wanted to know how the presence of untreated rats affected the helping behavior. Counter to the prediction of the bystander effect, duos and trios of rats actually were more likely to help than solo rats.
"At first, I thought the experiment had failed," Havlik said. "But after doing more research into human studies, we realized that behavior has actually been mirrored in people, too."
In research published last year, an analysis of surveillance videos revealed that groups of bystanders helped in more than 90% of violent encounters.
Read more at Science Daily
The study, titled "The Bystander Effect in Rats," also demonstrated that in the presence of other potential helper rats, rats are more, rather than less, likely to help. Whether helping is facilitated or suppressed depends on the circumstances rather than on personal temperament or morals, a finding with implications for human society. The research, published in the July 8 issue of Science Advances, builds off previous research on rat empathy.
In 2011, Peggy Mason, PhD, professor of neurobiology and senior author of the study, and her UChicago team of researchers found that rats consistently freed trapped companions, even saving a bit of chocolate for them, and this behavior was driven by a rat version of empathy. A subsequent study showed that rats treated with anti-anxiety medication are less likely to free a trapped peer because they do not feel its anxiety. In another study, researchers found that rats only freed trapped rat strains that they had previous social experience with.
The roots of the classic bystander effect date back to 1964, when Catherine "Kitty" Genovese was murdered in a crowded residential neighborhood in Queens, New York. An account published in the New York Times reported that 38 bystanders saw the murder but did not intervene. Though this story was later proven inaccurate, it inspired psychologists Bibb Latané and John Darley to investigate why so many people would fail to help.
The pair tested human subjects alone and in the presence of "confederate" bystanders -- people who were part of the research team and were instructed not to help -- as they confronted a variety of experimental scenarios with someone (an actor) in distress. Latané and Darley consistently observed that subjects were far less likely to help in the presence of non-helping confederates than they were when tested alone. This phenomenon, referred to as the bystander effect, is now a pillar in psychology, included in every introductory textbook and class. The mechanism for the classic bystander effect is thought to be a diffusion of responsibility whereby people reason that they need not act because others in a group will.
First author John Havlik was a UChicago undergraduate in Mason's laboratory, when the topic of the bystander effect came up during a lab meeting.
"My students had been bugging me to do this experiment for years," said Mason. "But it wasn't until John came along and would not let the idea go that we took the plunge."
Havlik, now a student at the Yale School of Medicine, spearheaded experiments to examine whether rats, which lack complex reasoning skills, would show a classical bystander effect.
The research team used their trapped rat paradigm in combination with rats that were made into "confederates" by administering an antianxiety drug that made them indifferent to another rat's distress, ensuring that they would not help. The team found that rats tested with confederates were less likely to help than those tested alone -- a bystander effect in rats. Digging deeper, they saw that the presence of confederates blocked reinforcement for helping.
"It's worse to have a non-responsive audience than to be alone," Mason said. "The rats try helping, but it's just not a rewarding experience because the other rats don't appear to care. It's as though the rat was saying to himself, 'I helped yesterday and no one cared. Not doing that again.' "
Mason and her team then wanted to know how the presence of untreated rats affected the helping behavior. Counter to the prediction of the bystander effect, duos and trios of rats actually were more likely to help than solo rats.
"At first, I thought the experiment had failed," Havlik said. "But after doing more research into human studies, we realized that behavior has actually been mirrored in people, too."
In research published last year, an analysis of surveillance videos revealed that groups of bystanders helped in more than 90% of violent encounters.
Read more at Science Daily
Study sheds light on how cancer spreads in blood
A new study sheds light on proteins in particles called extracellular vesicles, which are released by tumor cells into the bloodstream and promote the spread of cancer. The findings suggest how a blood test involving these vesicles might be used to diagnose cancer in the future, avoiding the need for invasive surgical biopsies.
The research is a large-scale analysis of what are known as palmitoylated proteins inside extracellular vesicles, according to Dolores Di Vizio, MD, PhD, professor of Surgery, Biomedical Sciences and Pathology and Laboratory Medicine at Cedars-Sinai. Di Vizio is co-corresponding author of the study, published online June 10 in the Journal of Extracellular Vesicles.
Extracellular vesicles have gained significant attention in the last decade because they contain proteins and other biologically important molecules whose information can be transferred from cell to cell. They are known to help cancer metastasize to distant sites in the body, but exactly how this happens is not clear.
To learn more about this process, the research team looked into a process called palmitoylation, in which enzymes transfer lipid molecules onto proteins. Palmitoylation can affect where proteins are located within cells, their activities and their contribution to cancer progression.
The investigators examined two types of extracellular vesicles, small and large, in samples of human prostate cancer cells. Using centrifuges, they separated the extracellular vesicles from the other cell materials and analyzed the levels of palmitoylation and the types of proteins present.
The team found extracellular vesicles derived from the cancer cells contained palmitoylated proteins that are associated with the spread of cancer. Further, when the team chemically suppressed the palmitoylation process, the level of some of these proteins went down in the extracellular vesicles.
"Our results suggest that protein palmitoylation may be involved in the selective packaging of proteins to different extracellular vesicle populations in the body," Di Vizio said. "This finding raises the possibility that by examining these proteins in extracellular vesicles in the bloodstream, we may be able to detect and characterize cancer in a patient in the future without performing a surgical biopsy."
Di Vizio said the next step in the research is to conduct a study in collaboration with her Cedars-Sinai colleagues and industry partners that will use advanced technologies, including mass spectrometry and flow cytometry, with the goal of identifying clinically significant prostate cancer at diagnosis.
Read more at Science Daily
The research is a large-scale analysis of what are known as palmitoylated proteins inside extracellular vesicles, according to Dolores Di Vizio, MD, PhD, professor of Surgery, Biomedical Sciences and Pathology and Laboratory Medicine at Cedars-Sinai. Di Vizio is co-corresponding author of the study, published online June 10 in the Journal of Extracellular Vesicles.
Extracellular vesicles have gained significant attention in the last decade because they contain proteins and other biologically important molecules whose information can be transferred from cell to cell. They are known to help cancer metastasize to distant sites in the body, but exactly how this happens is not clear.
To learn more about this process, the research team looked into a process called palmitoylation, in which enzymes transfer lipid molecules onto proteins. Palmitoylation can affect where proteins are located within cells, their activities and their contribution to cancer progression.
The investigators examined two types of extracellular vesicles, small and large, in samples of human prostate cancer cells. Using centrifuges, they separated the extracellular vesicles from the other cell materials and analyzed the levels of palmitoylation and the types of proteins present.
The team found extracellular vesicles derived from the cancer cells contained palmitoylated proteins that are associated with the spread of cancer. Further, when the team chemically suppressed the palmitoylation process, the level of some of these proteins went down in the extracellular vesicles.
"Our results suggest that protein palmitoylation may be involved in the selective packaging of proteins to different extracellular vesicle populations in the body," Di Vizio said. "This finding raises the possibility that by examining these proteins in extracellular vesicles in the bloodstream, we may be able to detect and characterize cancer in a patient in the future without performing a surgical biopsy."
Di Vizio said the next step in the research is to conduct a study in collaboration with her Cedars-Sinai colleagues and industry partners that will use advanced technologies, including mass spectrometry and flow cytometry, with the goal of identifying clinically significant prostate cancer at diagnosis.
Read more at Science Daily
Jul 8, 2020
New collection of stars, not born in our galaxy, discovered in Milky Way
Astronomers can go their whole career without finding a new object in the sky. But for Lina Necib, a postdoctoral scholar in theoretical physics at Caltech, the discovery of a cluster of stars in the Milky Way, but not born of the Milky Way, came early -- with a little help from supercomputers, the Gaia space observatory, and new deep learning methods.
Writing in Nature Astronomy this week, Necib and her collaborators describe Nyx, a vast new stellar stream in the vicinity of the Sun, that may provide the first indication that a dwarf galaxy had merged with the Milky Way disk. These stellar streams are thought to be globular clusters or dwarf galaxies that have been stretched out along its orbit by tidal forces before being completely disrupted.
The discovery of Nyx took a circuitous route, but one that reflects the multifaceted way astronomy and astrophysics are studied today.
FIRE in the Cosmos
Necib studies the kinematics -- or motions -- of stars and dark matter in the Milky Way. "If there are any clumps of stars that are moving together in a particular fashion, that usually tells us that there is a reason that they're moving together."
Since 2014, researchers from Caltech, Northwestern University, UC San Diego and UC Berkeley, among other institutions, have been developing highly-detailed simulations of realistic galaxies as part of a project called FIRE (Feedback In Realistic Environments). These simulations include everything scientists know about how galaxies form and evolve. Starting from the virtual equivalent of the beginning of time, the simulations produce galaxies that look and act much like our own.
Mapping the Milky Way
Concurrent to the FIRE project, the Gaia space observatory was launched in 2013 by the European Space Agency. Its goal is to create an extraordinarily precise three-dimensional map of about one billion stars throughout the Milky Way galaxy and beyond.
"It's the largest kinematic study to date. The observatory provides the motions of one billion stars," she explained. "A subset of it, seven million stars, have 3D velocities, which means that we can know exactly where a star is and its motion. We've gone from very small datasets to doing massive analyses that we couldn't do before to understand the structure of the Milky Way."
The discovery of Nyx involved combining these two major astrophysics projects and analyzing them using deep learning methods.
Among the questions that both the simulations and the sky survey address is: How did the Milky Way become what it is today?
"Galaxies form by swallowing other galaxies," Necib said. "We've assumed that the Milky Way had a quiet merger history, and for a while it was concerning how quiet it was because our simulations show a lot of mergers. Now, with access to a lot of smaller structures, we understand it wasn't as quiet as it seemed. It's very powerful to have all these tools, data and simulations. All of them have to be used at once to disentangle this problem. We're at the beginning stages of being able to really understand the formation of the Milky way."
Applying Deep Learning to Gaia
A map of a billion stars is a mixed blessing: so much information, but nearly impossible to parse by human perception.
"Before, astronomers had to do a lot of looking and plotting, and maybe use some clustering algorithms. But that's not really possible anymore," Necib said. "We can't stare at seven million stars and figure out what they're doing. What we did in this series of projects was use the Gaia mock catalogues."
The Gaia mock catalogue, developed by Robyn Sanderson (University of Pennsylvania), essentially asked: 'If the FIRE simulations were real and observed with Gaia, what would we see?'
Necib's collaborator, Bryan Ostdiek (formerly at University of Oregon, and now at Harvard University), who had previously been involved in the Large Hadron Collider (LHC) project, had experience dealing with huge datasets using machine and deep learning. Porting those methods over to astrophysics opened the door to a new way to explore the cosmos.
"At the LHC, we have incredible simulations, but we worry that machines trained on them may learn the simulation and not real physics," Ostdiek said. "In a similar way, the FIRE galaxies provide a wonderful environment to train our models, but they are not the Milky Way. We had to learn not only what could help us identify the interesting stars in simulation, but also how to get this to generalize to our real galaxy."
The team developed a method of tracking the movements of each star in the virtual galaxies and labelling the stars as either born in the host galaxy or accreted as the products of galaxy mergers. The two types of stars have different signatures, though the differences are often subtle. These labels were used to train the deep learning model, which was then tested on other FIRE simulations.
After they built the catalogue, they applied it to the Gaia data. "We asked the neural network, 'Based on what you've learned, can you label if the stars were accreted or not?'" Necib said.
The model ranked how confident it was that a star was born outside the Milky Way on a range from 0 to 1. The team created a cutoff with a tolerance for error and began exploring the results.
This approach of applying a model trained on one dataset and applying it to a different but related one is called transfer learning and can be fraught with challenges. "We needed to make sure that we're not learning artificial things about the simulation, but really what's going on in the data," Necib said. "For that, we had to give it a little bit of help and tell it to reweigh certain known elements to give it a bit of an anchor."
They first checked to see if it could identify known features of the galaxy. These include "the Gaia sausage" -- the remains of a dwarf galaxy that merged with the Milky Way about six to ten billion years ago and that has a distinctive sausage-like orbital shape.
"It has a very specific signature," she explained. "If the neural network worked the way it's supposed to, we should see this huge structure that we already know is there."
The Gaia sausage was there, as was the stellar halo -- background stars that give the Milky Way its tell-tale shape -- and the Helmi stream, another known dwarf galaxy that merged with the Milky Way in the distant past and was discovered in 1999.
First Sighting: Nyx
The model identified another structure in the analysis: a cluster of 250 stars, rotating with the Milky Way's disk, but also going toward the center of the galaxy.
"Your first instinct is that you have a bug," Necib recounted. "And you're like, 'Oh no!' So, I didn't tell any of my collaborators for three weeks. Then I started realizing it's not a bug, it's actually real and it's new."
But what if it had already been discovered? "You start going through the literature, making sure that nobody has seen it and luckily for me, nobody had. So I got to name it, which is the most exciting thing in astrophysics. I called it Nyx, the Greek goddess of the night. This particular structure is very interesting because it would have been very difficult to see without machine learning."
The project required advanced computing at many different stages. The FIRE and updated FIRE-2 simulations are among the largest computer models of galaxies ever attempted. Each of the nine main simulations -- three separate galaxy formations, each with slightly different starting point for the sun -- took months to compute on the largest, fastest supercomputers in the world. These included Blue Waters at the National Center for Supercomputing Applications (NCSA), NASA's High-End Computing facilities, and most recently Stampede2 at the Texas Advanced Computing Center (TACC).
The researchers used clusters at the University of Oregon to train the deep learning model and to apply it to the massive Gaia dataset. They are currently using Frontera, the fastest system at any university in the world, to continue the work.
"Everything about this project is computationally very intensive and would not be able to happen without large-scale computing," Necib said.
Future Steps
Necib and her team plan to explore Nyx further using ground-based telescopes. This will provide information about the chemical makeup of the stream, and other details that will help them date Nyx's arrival into the Milky Way, and possibly provide clues on where it came from.
The next data release of Gaia in 2021 will contain additional information about 100 million stars in the catalogue, making more discoveries of accreted clusters likely.
"When the Gaia mission started, astronomers knew it was one of the largest datasets that they were going to get, with lots to be excited about," Necib said. "But we needed to evolve our techniques to adapt to the dataset. If we didn't change or update our methods, we'd be missing out on physics that are in our dataset."
Read more at Science Daily
Writing in Nature Astronomy this week, Necib and her collaborators describe Nyx, a vast new stellar stream in the vicinity of the Sun, that may provide the first indication that a dwarf galaxy had merged with the Milky Way disk. These stellar streams are thought to be globular clusters or dwarf galaxies that have been stretched out along its orbit by tidal forces before being completely disrupted.
The discovery of Nyx took a circuitous route, but one that reflects the multifaceted way astronomy and astrophysics are studied today.
FIRE in the Cosmos
Necib studies the kinematics -- or motions -- of stars and dark matter in the Milky Way. "If there are any clumps of stars that are moving together in a particular fashion, that usually tells us that there is a reason that they're moving together."
Since 2014, researchers from Caltech, Northwestern University, UC San Diego and UC Berkeley, among other institutions, have been developing highly-detailed simulations of realistic galaxies as part of a project called FIRE (Feedback In Realistic Environments). These simulations include everything scientists know about how galaxies form and evolve. Starting from the virtual equivalent of the beginning of time, the simulations produce galaxies that look and act much like our own.
Mapping the Milky Way
Concurrent to the FIRE project, the Gaia space observatory was launched in 2013 by the European Space Agency. Its goal is to create an extraordinarily precise three-dimensional map of about one billion stars throughout the Milky Way galaxy and beyond.
"It's the largest kinematic study to date. The observatory provides the motions of one billion stars," she explained. "A subset of it, seven million stars, have 3D velocities, which means that we can know exactly where a star is and its motion. We've gone from very small datasets to doing massive analyses that we couldn't do before to understand the structure of the Milky Way."
The discovery of Nyx involved combining these two major astrophysics projects and analyzing them using deep learning methods.
Among the questions that both the simulations and the sky survey address is: How did the Milky Way become what it is today?
"Galaxies form by swallowing other galaxies," Necib said. "We've assumed that the Milky Way had a quiet merger history, and for a while it was concerning how quiet it was because our simulations show a lot of mergers. Now, with access to a lot of smaller structures, we understand it wasn't as quiet as it seemed. It's very powerful to have all these tools, data and simulations. All of them have to be used at once to disentangle this problem. We're at the beginning stages of being able to really understand the formation of the Milky way."
Applying Deep Learning to Gaia
A map of a billion stars is a mixed blessing: so much information, but nearly impossible to parse by human perception.
"Before, astronomers had to do a lot of looking and plotting, and maybe use some clustering algorithms. But that's not really possible anymore," Necib said. "We can't stare at seven million stars and figure out what they're doing. What we did in this series of projects was use the Gaia mock catalogues."
The Gaia mock catalogue, developed by Robyn Sanderson (University of Pennsylvania), essentially asked: 'If the FIRE simulations were real and observed with Gaia, what would we see?'
Necib's collaborator, Bryan Ostdiek (formerly at University of Oregon, and now at Harvard University), who had previously been involved in the Large Hadron Collider (LHC) project, had experience dealing with huge datasets using machine and deep learning. Porting those methods over to astrophysics opened the door to a new way to explore the cosmos.
"At the LHC, we have incredible simulations, but we worry that machines trained on them may learn the simulation and not real physics," Ostdiek said. "In a similar way, the FIRE galaxies provide a wonderful environment to train our models, but they are not the Milky Way. We had to learn not only what could help us identify the interesting stars in simulation, but also how to get this to generalize to our real galaxy."
The team developed a method of tracking the movements of each star in the virtual galaxies and labelling the stars as either born in the host galaxy or accreted as the products of galaxy mergers. The two types of stars have different signatures, though the differences are often subtle. These labels were used to train the deep learning model, which was then tested on other FIRE simulations.
After they built the catalogue, they applied it to the Gaia data. "We asked the neural network, 'Based on what you've learned, can you label if the stars were accreted or not?'" Necib said.
The model ranked how confident it was that a star was born outside the Milky Way on a range from 0 to 1. The team created a cutoff with a tolerance for error and began exploring the results.
This approach of applying a model trained on one dataset and applying it to a different but related one is called transfer learning and can be fraught with challenges. "We needed to make sure that we're not learning artificial things about the simulation, but really what's going on in the data," Necib said. "For that, we had to give it a little bit of help and tell it to reweigh certain known elements to give it a bit of an anchor."
They first checked to see if it could identify known features of the galaxy. These include "the Gaia sausage" -- the remains of a dwarf galaxy that merged with the Milky Way about six to ten billion years ago and that has a distinctive sausage-like orbital shape.
"It has a very specific signature," she explained. "If the neural network worked the way it's supposed to, we should see this huge structure that we already know is there."
The Gaia sausage was there, as was the stellar halo -- background stars that give the Milky Way its tell-tale shape -- and the Helmi stream, another known dwarf galaxy that merged with the Milky Way in the distant past and was discovered in 1999.
First Sighting: Nyx
The model identified another structure in the analysis: a cluster of 250 stars, rotating with the Milky Way's disk, but also going toward the center of the galaxy.
"Your first instinct is that you have a bug," Necib recounted. "And you're like, 'Oh no!' So, I didn't tell any of my collaborators for three weeks. Then I started realizing it's not a bug, it's actually real and it's new."
But what if it had already been discovered? "You start going through the literature, making sure that nobody has seen it and luckily for me, nobody had. So I got to name it, which is the most exciting thing in astrophysics. I called it Nyx, the Greek goddess of the night. This particular structure is very interesting because it would have been very difficult to see without machine learning."
The project required advanced computing at many different stages. The FIRE and updated FIRE-2 simulations are among the largest computer models of galaxies ever attempted. Each of the nine main simulations -- three separate galaxy formations, each with slightly different starting point for the sun -- took months to compute on the largest, fastest supercomputers in the world. These included Blue Waters at the National Center for Supercomputing Applications (NCSA), NASA's High-End Computing facilities, and most recently Stampede2 at the Texas Advanced Computing Center (TACC).
The researchers used clusters at the University of Oregon to train the deep learning model and to apply it to the massive Gaia dataset. They are currently using Frontera, the fastest system at any university in the world, to continue the work.
"Everything about this project is computationally very intensive and would not be able to happen without large-scale computing," Necib said.
Future Steps
Necib and her team plan to explore Nyx further using ground-based telescopes. This will provide information about the chemical makeup of the stream, and other details that will help them date Nyx's arrival into the Milky Way, and possibly provide clues on where it came from.
The next data release of Gaia in 2021 will contain additional information about 100 million stars in the catalogue, making more discoveries of accreted clusters likely.
"When the Gaia mission started, astronomers knew it was one of the largest datasets that they were going to get, with lots to be excited about," Necib said. "But we needed to evolve our techniques to adapt to the dataset. If we didn't change or update our methods, we'd be missing out on physics that are in our dataset."
Read more at Science Daily
How colliding neutron stars could shed light on universal mysteries
An important breakthrough in how we can understand dead star collisions and the expansion of the Universe has been made by an international team, led by the University of East Anglia.
They have discovered an unusual pulsar -- one of deep space's magnetized spinning neutron-star 'lighthouses' that emits highly focused radio waves from its magnetic poles.
The newly discovered pulsar (known as PSR J1913+1102) is part of a binary system -- which means that it is locked in a fiercely tight orbit with another neutron star.
Neutron stars are the dead stellar remnants of a supernova. They are made up of the most dense matter known -- packing hundreds of thousands of times the Earth's mass into a sphere the size of a city.
In around half a billion years the two neutron stars will collide, releasing astonishing amounts of energy in the form of gravitational waves and light.
But the newly discovered pulsar is unusual because the masses of its two neutron stars are quite different -- with one far larger than the other.
This asymmetric system gives scientists confidence that double neutron star mergers will provide vital clues about unsolved mysteries in astrophysics -- including a more accurate determination of the expansion rate of the Universe, known as the Hubble constant.
The discovery, published today in the journal Nature, was made using the Arecibo radio telescope in Puerto Rico.
Lead researcher Dr Robert Ferdman, from UEA's School of Physics, said: "Back in 2017, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) first detected the merger of two neutron stars.
"The event caused gravitational-wave ripples through the fabric of space time, as predicted by Albert Einstein over a century ago."
Known as GW170817, this spectacular event was also seen with traditional telescopes at observatories around the world, which identified its location in a distant galaxy, 130 million light years from our own Milky Way.
Dr Ferdman said: "It confirmed that the phenomenon of short gamma-ray bursts was due to the merger of two neutron stars. And these are now thought to be the factories that produce most of the heaviest elements in the Universe, such as gold."
The power released during the fraction of a second when two neutron stars merge is enormous -- estimated to be tens of times larger than all stars in the Universe combined.
So the GW170817 event was not surprising. But the enormous amount of matter ejected from the merger and its brightness was an unexpected mystery.
Dr Ferdman said: "Most theories about this event assumed that neutron stars locked in binary systems are very similar in mass.
"Our new discovery changes these assumptions. We have uncovered a binary system containing two neutron stars with very different masses.
"These stars will collide and merge in around 470 million years, which seems like a long time, but it is only a small fraction of the age of the Universe.
"Because one neutron star is significantly larger, its gravitational influence will distort the shape of its companion star -- stripping away large amounts of matter just before they actually merge, and potentially disrupting it altogether.
"This 'tidal disruption' ejects a larger amount of hot material than expected for equal-mass binary systems, resulting in a more powerful emission.
"Although GW170817 can be explained by other theories, we can confirm that a parent system of neutron stars with significantly different masses, similar to the PSR J1913+1102 system, is a very plausible explanation.
"Perhaps more importantly, the discovery highlights that there are many more of these systems out there -- making up more than one in 10 merging double neutron star binaries."
Co-author Dr Paulo Freire from the Max Planck Institute for Radio Astronomy in Bonn, Germany, said: "Such a disruption would allow astrophysicists to gain important new clues about the exotic matter that makes up the interiors of these extreme, dense objects.
"This matter is still a major mystery -- it's so dense that scientists still don't know what it is actually made of. These densities are far beyond what we can reproduce in Earth-based laboratories."
The disruption of the lighter neutron star would also enhance the brightness of the material ejected by the merger. This means that along with gravitational-wave detectors such as the US-based LIGO and the Europe-based Virgo detector, scientists will also be able to observe them with conventional telescopes.
Read more at Science Daily
They have discovered an unusual pulsar -- one of deep space's magnetized spinning neutron-star 'lighthouses' that emits highly focused radio waves from its magnetic poles.
The newly discovered pulsar (known as PSR J1913+1102) is part of a binary system -- which means that it is locked in a fiercely tight orbit with another neutron star.
Neutron stars are the dead stellar remnants of a supernova. They are made up of the most dense matter known -- packing hundreds of thousands of times the Earth's mass into a sphere the size of a city.
In around half a billion years the two neutron stars will collide, releasing astonishing amounts of energy in the form of gravitational waves and light.
But the newly discovered pulsar is unusual because the masses of its two neutron stars are quite different -- with one far larger than the other.
This asymmetric system gives scientists confidence that double neutron star mergers will provide vital clues about unsolved mysteries in astrophysics -- including a more accurate determination of the expansion rate of the Universe, known as the Hubble constant.
The discovery, published today in the journal Nature, was made using the Arecibo radio telescope in Puerto Rico.
Lead researcher Dr Robert Ferdman, from UEA's School of Physics, said: "Back in 2017, scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) first detected the merger of two neutron stars.
"The event caused gravitational-wave ripples through the fabric of space time, as predicted by Albert Einstein over a century ago."
Known as GW170817, this spectacular event was also seen with traditional telescopes at observatories around the world, which identified its location in a distant galaxy, 130 million light years from our own Milky Way.
Dr Ferdman said: "It confirmed that the phenomenon of short gamma-ray bursts was due to the merger of two neutron stars. And these are now thought to be the factories that produce most of the heaviest elements in the Universe, such as gold."
The power released during the fraction of a second when two neutron stars merge is enormous -- estimated to be tens of times larger than all stars in the Universe combined.
So the GW170817 event was not surprising. But the enormous amount of matter ejected from the merger and its brightness was an unexpected mystery.
Dr Ferdman said: "Most theories about this event assumed that neutron stars locked in binary systems are very similar in mass.
"Our new discovery changes these assumptions. We have uncovered a binary system containing two neutron stars with very different masses.
"These stars will collide and merge in around 470 million years, which seems like a long time, but it is only a small fraction of the age of the Universe.
"Because one neutron star is significantly larger, its gravitational influence will distort the shape of its companion star -- stripping away large amounts of matter just before they actually merge, and potentially disrupting it altogether.
"This 'tidal disruption' ejects a larger amount of hot material than expected for equal-mass binary systems, resulting in a more powerful emission.
"Although GW170817 can be explained by other theories, we can confirm that a parent system of neutron stars with significantly different masses, similar to the PSR J1913+1102 system, is a very plausible explanation.
"Perhaps more importantly, the discovery highlights that there are many more of these systems out there -- making up more than one in 10 merging double neutron star binaries."
Co-author Dr Paulo Freire from the Max Planck Institute for Radio Astronomy in Bonn, Germany, said: "Such a disruption would allow astrophysicists to gain important new clues about the exotic matter that makes up the interiors of these extreme, dense objects.
"This matter is still a major mystery -- it's so dense that scientists still don't know what it is actually made of. These densities are far beyond what we can reproduce in Earth-based laboratories."
The disruption of the lighter neutron star would also enhance the brightness of the material ejected by the merger. This means that along with gravitational-wave detectors such as the US-based LIGO and the Europe-based Virgo detector, scientists will also be able to observe them with conventional telescopes.
Read more at Science Daily
Animals who try to sound 'bigger' are good at learning sounds
Some animals fake their body size by sounding 'bigger' than they actually are. Researchers studied 164 different mammals and found that animals who lower their voice to sound bigger are often skilled vocalists. Both strategies -- sounding bigger and learning sounds -- are likely driven by sexual selection, and may play a role in explaining the origins of human speech evolution.
"If you saw a Chihuahua barking as deep as a Rottweiler, you would definitely be surprised," says Andrea Ravignani, a researcher at the MPI and the Dutch Sealcentre Pieterburen. Body size influences the frequency of the sounds animals produce, but many animals found ways to sound 'smaller' or 'bigger' than expected. "Nature is full of animals like squeaky-Rottweilers and tenor-Chihuahuas," explains Ravignani. Some animals fake their size by developing larger vocal organs that lower their sound, which makes them sound larger than you would expect. Other animals are good at controlling the sounds they produce. Such strategies (called 'dishonest signalling' by biologists) could be driven by sexual selection, as males with larger body size or superior singing skills (hitting very high or low notes) attract more females (or vice versa).
Garcia and Ravignani wondered whether some animals may have learned to make new sounds as a strategy to attract mates. Few animal species are capable of vocal learning, among them mammals such as seals, dolphins, bats and elephants. For instance, seals can imitate sounds, and some seals copy call types of successfully breeding individuals. Would animals who often 'fake' their body size also be the ones capable of learning new sounds?
The researchers analysed the sounds and body size of 164 different mammals, ranging from mice and monkeys to water dwelling mammals such as the subantarctic fur seal and the Amazonian manatee. They combined methods from acoustics, anatomy, and evolutionary biology to compare the different sorts of animals in the dataset.
The scientists found that animals who 'fake' their body size are often skilled sound learners. According to Garcia and Ravignani, their framework provides a new way of investigating the evolution of communication systems. "We want to expand our theory to take into account other evolutionary pressures, not just sexual selection," adds Ravignani. "We also want to replicate our preliminary findings with more mammals and test whether our ideas also apply to birds or other taxonomic groups."
Read more at Science Daily
"If you saw a Chihuahua barking as deep as a Rottweiler, you would definitely be surprised," says Andrea Ravignani, a researcher at the MPI and the Dutch Sealcentre Pieterburen. Body size influences the frequency of the sounds animals produce, but many animals found ways to sound 'smaller' or 'bigger' than expected. "Nature is full of animals like squeaky-Rottweilers and tenor-Chihuahuas," explains Ravignani. Some animals fake their size by developing larger vocal organs that lower their sound, which makes them sound larger than you would expect. Other animals are good at controlling the sounds they produce. Such strategies (called 'dishonest signalling' by biologists) could be driven by sexual selection, as males with larger body size or superior singing skills (hitting very high or low notes) attract more females (or vice versa).
Garcia and Ravignani wondered whether some animals may have learned to make new sounds as a strategy to attract mates. Few animal species are capable of vocal learning, among them mammals such as seals, dolphins, bats and elephants. For instance, seals can imitate sounds, and some seals copy call types of successfully breeding individuals. Would animals who often 'fake' their body size also be the ones capable of learning new sounds?
The researchers analysed the sounds and body size of 164 different mammals, ranging from mice and monkeys to water dwelling mammals such as the subantarctic fur seal and the Amazonian manatee. They combined methods from acoustics, anatomy, and evolutionary biology to compare the different sorts of animals in the dataset.
The scientists found that animals who 'fake' their body size are often skilled sound learners. According to Garcia and Ravignani, their framework provides a new way of investigating the evolution of communication systems. "We want to expand our theory to take into account other evolutionary pressures, not just sexual selection," adds Ravignani. "We also want to replicate our preliminary findings with more mammals and test whether our ideas also apply to birds or other taxonomic groups."
Read more at Science Daily
The best (and worst) materials for masks
It's intuitive and scientifically shown that wearing a face covering can help reduce the spread of the novel coronavirus that causes COVID-19. But not all masks are created equal, according to new University of Arizona-led research.
Amanda Wilson, an environmental health sciences doctoral candidate in the Department of Community, Environment and Policy in the Mel and Enid Zuckerman College of Public Health, is lead author on a recent study published in the Journal of Hospital Infection that assessed the ability of a variety of nontraditional mask materials to protect a person from infection after 30 seconds and after 20 minutes of exposure in a highly contaminated environment.
When the researchers compared wearing masks to wearing no protection during 20-minute and 30-second exposures to the virus, they found that infection risks were reduced by 24-94% or by 44-99% depending on the mask and exposure duration. Risk reduction decreased as exposure duration increased, they found.
"N99 masks, which are even more efficient at filtering airborne particles than N95 masks, are obviously one of the best options for blocking the virus, as they can reduce average risk by 94-99% for 20-minute and 30-second exposures, but they can be hard to come by, and there are ethical considerations such as leaving those available for medical professionals," Wilson said.
The next best options, according to the research, are N95 and surgical masks and, perhaps surprisingly, vacuum cleaner filters, which can be inserted into filter pockets in cloth masks. The vacuum filters reduced infection risk by 83% for a 30-second exposure and 58% for a 20-minute exposure. Of the other nontraditional materials evaluated by the researchers, tea towels, cotton-blend fabrics and antimicrobial pillowcases were the next best for protection.
Scarves, which reduced infection risk by 44% after 30 seconds and 24% after 20 minutes, and similarly effective cotton t-shirts are only slightly better than wearing no mask at all, they found.
"We knew that masks work, but we wanted to know how well and compare different materials' effects on health outcomes," said Wilson, who specializes in quantitative microbial risk assessment.
Wilson and her team collected data from various studies of mask efficacy and created a computer model to simulate infection risk, taking various factors into consideration.
"One big component of risk is how long you're exposed. We compared risk of infection at both 30 seconds and 20 minutes in a highly contaminated environment," she said.
Other conditions that impact risk of infection are the number of people around you and their distance from you, she said.
The size of virus-transporting droplets from sneezes, coughs or even speech is also a very important factor. Larger, heavier droplets carrying the virus drop out of the air faster than smaller, lighter ones. That's one reason distance helps reduce exposure.
"Aerosol size can also be affected by humidity," Wilson said. "If the air is drier, then aerosols become smaller faster. If humidity is higher, then aerosols will stay larger for a longer period of time, dropping out faster. That might sound good at first, but then those aerosols fall on surfaces, and that object becomes another potential exposure route."
The study also showed that the more time a person spends in an environment where the virus is present, the less effective a mask becomes.
"That doesn't mean take your mask off after 20 minutes," Wilson said, "but it does mean that a mask can't reduce your risk to zero. Don't go to a bar for four hours and think you're risk free because you're wearing a mask. Stay home as much as possible, wash your hands often, wear a mask when you're out and don't touch your face."
Masks protect the wearer and others in a number of different ways. Wilson said there are two "intuitive ways" that masks filter larger aerosols: mechanical interception and inertial impaction.
"The denser the fibers of a material, the better it is at filtering. That's why higher thread counts lead to higher efficacy. There's just more to block the virus," she said. "But some masks (such as those made from silk) also have electrostatic properties, which can attract smaller particles and keep them from passing through the mask as well."
The model developed by Wilson and her colleagues included parameters such as inhalation rate -- the volume of air inhaled over time -- and virus concentration in the air.
"We took a lot of research data, put it into a mathematical model and related those data points to each other," Wilson said. "For example, if we know people's inhalation rates vary by this much and know this much virus is in the air and these materials offer this much efficiency in terms of filtration, what does that mean for infection risk? We provide a range, in part, because everyone is different, such as in how much air we breathe over time."
Wilson also said it's important for a mask to have a good seal that pinches at nose, and she noted that people shouldn't wear a mask beneath the nose or tuck it under the chin when not in use.
Read more at Science Daily
Amanda Wilson, an environmental health sciences doctoral candidate in the Department of Community, Environment and Policy in the Mel and Enid Zuckerman College of Public Health, is lead author on a recent study published in the Journal of Hospital Infection that assessed the ability of a variety of nontraditional mask materials to protect a person from infection after 30 seconds and after 20 minutes of exposure in a highly contaminated environment.
When the researchers compared wearing masks to wearing no protection during 20-minute and 30-second exposures to the virus, they found that infection risks were reduced by 24-94% or by 44-99% depending on the mask and exposure duration. Risk reduction decreased as exposure duration increased, they found.
"N99 masks, which are even more efficient at filtering airborne particles than N95 masks, are obviously one of the best options for blocking the virus, as they can reduce average risk by 94-99% for 20-minute and 30-second exposures, but they can be hard to come by, and there are ethical considerations such as leaving those available for medical professionals," Wilson said.
The next best options, according to the research, are N95 and surgical masks and, perhaps surprisingly, vacuum cleaner filters, which can be inserted into filter pockets in cloth masks. The vacuum filters reduced infection risk by 83% for a 30-second exposure and 58% for a 20-minute exposure. Of the other nontraditional materials evaluated by the researchers, tea towels, cotton-blend fabrics and antimicrobial pillowcases were the next best for protection.
Scarves, which reduced infection risk by 44% after 30 seconds and 24% after 20 minutes, and similarly effective cotton t-shirts are only slightly better than wearing no mask at all, they found.
"We knew that masks work, but we wanted to know how well and compare different materials' effects on health outcomes," said Wilson, who specializes in quantitative microbial risk assessment.
Wilson and her team collected data from various studies of mask efficacy and created a computer model to simulate infection risk, taking various factors into consideration.
"One big component of risk is how long you're exposed. We compared risk of infection at both 30 seconds and 20 minutes in a highly contaminated environment," she said.
Other conditions that impact risk of infection are the number of people around you and their distance from you, she said.
The size of virus-transporting droplets from sneezes, coughs or even speech is also a very important factor. Larger, heavier droplets carrying the virus drop out of the air faster than smaller, lighter ones. That's one reason distance helps reduce exposure.
"Aerosol size can also be affected by humidity," Wilson said. "If the air is drier, then aerosols become smaller faster. If humidity is higher, then aerosols will stay larger for a longer period of time, dropping out faster. That might sound good at first, but then those aerosols fall on surfaces, and that object becomes another potential exposure route."
The study also showed that the more time a person spends in an environment where the virus is present, the less effective a mask becomes.
"That doesn't mean take your mask off after 20 minutes," Wilson said, "but it does mean that a mask can't reduce your risk to zero. Don't go to a bar for four hours and think you're risk free because you're wearing a mask. Stay home as much as possible, wash your hands often, wear a mask when you're out and don't touch your face."
Masks protect the wearer and others in a number of different ways. Wilson said there are two "intuitive ways" that masks filter larger aerosols: mechanical interception and inertial impaction.
"The denser the fibers of a material, the better it is at filtering. That's why higher thread counts lead to higher efficacy. There's just more to block the virus," she said. "But some masks (such as those made from silk) also have electrostatic properties, which can attract smaller particles and keep them from passing through the mask as well."
The model developed by Wilson and her colleagues included parameters such as inhalation rate -- the volume of air inhaled over time -- and virus concentration in the air.
"We took a lot of research data, put it into a mathematical model and related those data points to each other," Wilson said. "For example, if we know people's inhalation rates vary by this much and know this much virus is in the air and these materials offer this much efficiency in terms of filtration, what does that mean for infection risk? We provide a range, in part, because everyone is different, such as in how much air we breathe over time."
Wilson also said it's important for a mask to have a good seal that pinches at nose, and she noted that people shouldn't wear a mask beneath the nose or tuck it under the chin when not in use.
Read more at Science Daily
Jul 7, 2020
Consumers prefer round numbers even when the specific number is better news
Consider this scenario: A vaccine for the novel coronavirus has been developed that is 91.27% effective. If public health officials present this information using the specific number, people are likely to think the vaccine is actually less effective than if it is presented as being 90% effective.
This concept is a real-life application of recent findings from Gaurav Jain, an assistant professor of marketing in the Lally School of Management at Rensselaer Polytechnic Institute, published recently in Organizational Behavior and Human Decision Process.
The paper, titled "Revisiting Attribute Framing: The Impact of Number Roundedness on Framing," explores an area of behavioral economics research pertaining to attribute framing, which evaluates how people make decisions based on the manner in which information is presented.
Watch this video to learn more.
For decades, researchers in this field have been focused on the attributes, the adjectives, and other words that describe what is being measured. In this paper, Jain looked at the numbers that are used in the frames themselves.
Using six sets of data with more than 1,500 participants, Jain and his co-authors considered what would happen to peoples' perception of information when specific, or non-round, numbers were used instead of round numbers.
The research showed that people find non-round numbers unique and jarring. Jain and his team determined that people pause to think about the specific number due to its uniqueness. Because it isn't easy to comprehend, people tend to compare the non-round number to an easily understood ideal standard -- like 100%. Then, because the specific number doesn't live up to the ideal, people perceive it negatively.
"Numbers have a language and give non-numerical perceptions," Jain said. "When we use specific numbers, the evaluations decrease. There was no apparent reason for this kind of behavior, and this was incredibly surprising."
While Jain and his team explored this question using standard behavioral economic research scenarios and not a specific question, such as communications regarding a potential coronavirus vaccine, this research has direct and critical impact in marketing and public health messaging.
"The extensive use of attribute framing in marketing, organizational behavior, and public policy communication and the robustness of the effects in experimental settings make it one of the most important and frequently studied phenomena in the field," Jain said. "Managers and public health officials should be careful when using non-round numbers, because the use of this approach in communication messages may decrease the subjective evaluations of the target on the associated attributes."
Read more at Science Daily
This concept is a real-life application of recent findings from Gaurav Jain, an assistant professor of marketing in the Lally School of Management at Rensselaer Polytechnic Institute, published recently in Organizational Behavior and Human Decision Process.
The paper, titled "Revisiting Attribute Framing: The Impact of Number Roundedness on Framing," explores an area of behavioral economics research pertaining to attribute framing, which evaluates how people make decisions based on the manner in which information is presented.
Watch this video to learn more.
For decades, researchers in this field have been focused on the attributes, the adjectives, and other words that describe what is being measured. In this paper, Jain looked at the numbers that are used in the frames themselves.
Using six sets of data with more than 1,500 participants, Jain and his co-authors considered what would happen to peoples' perception of information when specific, or non-round, numbers were used instead of round numbers.
The research showed that people find non-round numbers unique and jarring. Jain and his team determined that people pause to think about the specific number due to its uniqueness. Because it isn't easy to comprehend, people tend to compare the non-round number to an easily understood ideal standard -- like 100%. Then, because the specific number doesn't live up to the ideal, people perceive it negatively.
"Numbers have a language and give non-numerical perceptions," Jain said. "When we use specific numbers, the evaluations decrease. There was no apparent reason for this kind of behavior, and this was incredibly surprising."
While Jain and his team explored this question using standard behavioral economic research scenarios and not a specific question, such as communications regarding a potential coronavirus vaccine, this research has direct and critical impact in marketing and public health messaging.
"The extensive use of attribute framing in marketing, organizational behavior, and public policy communication and the robustness of the effects in experimental settings make it one of the most important and frequently studied phenomena in the field," Jain said. "Managers and public health officials should be careful when using non-round numbers, because the use of this approach in communication messages may decrease the subjective evaluations of the target on the associated attributes."
Read more at Science Daily
Our animal inheritance: Humans perk up their ears, too, when they hear interesting sounds
Many animals, including dogs, cats and various species of monkeys, will move their ears to better focus their attention on a novel sound. That humans also have this capability was not known until now. A research team based in Saarland has demonstrated for the first time that we make minute, unconscious movements of our ears that are directed towards the sound want to focus our attention on. The team discovered this ability by measuring electrical signals in the muscles of the vestigial motor system in the human ear. The results have now been published in the journal eLife.
Asking children to 'perk up their ears' means asking them to listen intently. Nobody seriously thinks that kids literally move their ears the way that cats, dogs or horses do. But the fact is, they do, as researchers at the Systems Neuroscience & Neurotechnology Unit (SNNU) have now shown. The research team, led by Professor Danial Strauss, has shown that the muscles around the ear become active as soon as novel, unusual or goal-relevant sounds are perceived. 'The electrical activity of the ear muscles indicates the direction in which the subject is focusing their auditory attention,' says neuroscientist and computer scientist Strauss. 'It is very likely that humans still possess a rudimentary orientation system that tries to control the movement of the pinna (the visible outer part of the ear). Despite becoming vestigial about 25 million years ago, this system still exists as a "neural fossil" within our brains,' explains Professor Strauss. The question why pinna orienting was lost during the evolution of the primate lineage has still not been completely resolved.
The researchers were able to record the signals that control the minute, generally invisible, movements of the pinna using a technique known as surface electromyography (EMG). Sensors attached to the subject's skin detected the electrical activity of the muscles responsible for moving the pinna or altering its shape. Two types of attention were examined. To assess the reflexive attention that occurs automatically when we hear unexpected sounds, the participants in the study were exposed to novel sounds coming at random intervals from different lateral positions while they silently read a monotonous text. To test the goal-directed attention that we show when actively listening, the participants were asked to listen to a short story coming from one laterally positioned speaker, while ignoring a 'competing' story from a speaker located on the opposite side. Both experiments showed that muscle movements in the vestigial pinna-orienting system indicate the direction of the subject's auditory attention.
To better characterize these minute movements of the ear, the team also made special high-definition video recordings of the subjects during the experiments. The subtle movements of the ears were made visible by applying computer-based motion magnification techniques. Depending on the type of aural stimulus used, the researchers were able to observe different upward movements of the ear as well as differences in the strength of the rearward motion of the pinna's upper-lateral edge.
'Our results show that electromyography of the ear muscles offers a simple means of measuring auditory attention. The technique is not restricted to fundamental research, it also has potential for a number of interesting applications," explains Professor Strauss. One area of great practical relevance would be in developing better hearing aids. 'These devices would be able to amplify the sounds that the wearer is trying to hear, while suppressing the noises that they are trying to ignore. The device would function in a way that reflects the user's auditory intention.' The hearing aid would almost instantaneously register and interpret the electrical activity in the ear muscles. A miniature processor would gauge the direction the user is trying to direct their attention towards and then adjust the gain on the device's directional microphones accordingly.
Read more at Science Daily
Asking children to 'perk up their ears' means asking them to listen intently. Nobody seriously thinks that kids literally move their ears the way that cats, dogs or horses do. But the fact is, they do, as researchers at the Systems Neuroscience & Neurotechnology Unit (SNNU) have now shown. The research team, led by Professor Danial Strauss, has shown that the muscles around the ear become active as soon as novel, unusual or goal-relevant sounds are perceived. 'The electrical activity of the ear muscles indicates the direction in which the subject is focusing their auditory attention,' says neuroscientist and computer scientist Strauss. 'It is very likely that humans still possess a rudimentary orientation system that tries to control the movement of the pinna (the visible outer part of the ear). Despite becoming vestigial about 25 million years ago, this system still exists as a "neural fossil" within our brains,' explains Professor Strauss. The question why pinna orienting was lost during the evolution of the primate lineage has still not been completely resolved.
The researchers were able to record the signals that control the minute, generally invisible, movements of the pinna using a technique known as surface electromyography (EMG). Sensors attached to the subject's skin detected the electrical activity of the muscles responsible for moving the pinna or altering its shape. Two types of attention were examined. To assess the reflexive attention that occurs automatically when we hear unexpected sounds, the participants in the study were exposed to novel sounds coming at random intervals from different lateral positions while they silently read a monotonous text. To test the goal-directed attention that we show when actively listening, the participants were asked to listen to a short story coming from one laterally positioned speaker, while ignoring a 'competing' story from a speaker located on the opposite side. Both experiments showed that muscle movements in the vestigial pinna-orienting system indicate the direction of the subject's auditory attention.
To better characterize these minute movements of the ear, the team also made special high-definition video recordings of the subjects during the experiments. The subtle movements of the ears were made visible by applying computer-based motion magnification techniques. Depending on the type of aural stimulus used, the researchers were able to observe different upward movements of the ear as well as differences in the strength of the rearward motion of the pinna's upper-lateral edge.
'Our results show that electromyography of the ear muscles offers a simple means of measuring auditory attention. The technique is not restricted to fundamental research, it also has potential for a number of interesting applications," explains Professor Strauss. One area of great practical relevance would be in developing better hearing aids. 'These devices would be able to amplify the sounds that the wearer is trying to hear, while suppressing the noises that they are trying to ignore. The device would function in a way that reflects the user's auditory intention.' The hearing aid would almost instantaneously register and interpret the electrical activity in the ear muscles. A miniature processor would gauge the direction the user is trying to direct their attention towards and then adjust the gain on the device's directional microphones accordingly.
Read more at Science Daily
How does Earth sustain its magnetic field?
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| Earth's magnetic field and Sun's solar wind |
Life as we know it could not exist without Earth's magnetic field and its ability to deflect dangerous ionizing particles from the solar wind and more far-flung cosmic rays. It is continuously generated by the motion of liquid iron in Earth's outer core, a phenomenon called the geodynamo.
Despite its fundamental importance, many questions remain unanswered about the geodynamo's origin and the energy sources that have sustained it over the millennia.
New work from an international team of researchers, including current and former Carnegie scientists Alexander Goncharov, Nicholas Holtgrewe, Sergey Lobanov, and Irina Chuvashova examines how the presence of lighter elements in the predominately iron core could affect the geodynamo's genesis and sustainability. Their findings are published by Nature Communications.
Our planet accreted from the disk of dust and gas that surrounded our Sun in its youth. Eventually, the densest material sank inward in the forming planet, creating the layers that exist today -- core, mantle, and crust. Although, the core is predominately iron, seismic data indicates that some lighter elements like oxygen, silicon, sulfur, carbon, and hydrogen, were dissolved into it during the differentiation process.
Over time, the inner core crystallized and has been continuously cooling since then. On its own, could heat flowing out of the core and into the mantle drive the geodynamo? Or does this thermal convection need an extra boost from the buoyancy of light elements, not just heat, moving out of a condensing inner core?
Understanding the specifics of the core's chemical composition can help answer this question.
Silicates are predominant in the mantle, and after oxygen and iron, silicon is the third-most-abundant element in the Earth, so it is a likely option for one of the main lighter elements that could be alloyed with iron in the core. Led by Wen-Pin Hsieh of Academia Sinica and National Taiwan University, the researchers used lab-based mimicry of deep Earth conditions to simulate how the presence of silicon would affect the transmission of heat from the planet's iron core out into the mantle.
"The less thermally conductive the core material is, the lower the threshold needed to generate the geodynamo," Goncharov explained. "With a low enough threshold, the heat flux out of the core could be driven entirely by the thermal convection, with no need for the additional movement of material to make it work."
The team found that a concentration of about 8 weight percent silicon in their simulated inner core, the geodynamo could have functioned on heat transmission alone for the planet's entire history.
Looking forward, they want to expand their efforts to understand how the presence of oxygen, sulfur, and carbon in the core would influence this convection process.
Read more at Science Daily
A tiny ancient relative of dinosaurs and pterosaurs discovered
Dinosaurs and flying pterosaurs may be known for their remarkable size, but a newly described species from Madagascar that lived around 237 million years ago suggests that they originated from extremely small ancestors. The fossil reptile, named Kongonaphon kely, or "tiny bug slayer," would have stood just 10 centimeters (or about 4 inches) tall. The description and analysis of this fossil and its relatives, published today in the journal Proceedings of the National Academy of Sciences, may help explain the origins of flight in pterosaurs, the presence of "fuzz" on the skin of both pterosaurs and dinosaurs, and other questions about these charismatic animals.
"There's a general perception of dinosaurs as being giants," said Christian Kammerer, a research curator in paleontology at the North Carolina Museum of Natural Sciences and a former Gerstner Scholar at the American Museum of Natural History. "But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it's shockingly small."
Dinosaurs and pterosaurs both belong to the group Ornithodira. Their origins, however, are poorly known, as few specimens from near the root of this lineage have been found. The fossils of Kongonaphon were discovered in 1998 in Madagascar by a team of researchers led by American Museum of Natural History Frick Curator of Fossil Mammals John Flynn (who worked at The Field Museum at the time) in close collaboration with scientists and students at the University of Antananarivo, and project co-leader Andre Wyss, chair and professor of the University of California-Santa Barbara's Department of Earth Science and an American Museum of Natural History research associate.
"This fossil site in southwestern Madagascar from a poorly known time interval globally has produced some amazing fossils, and this tiny specimen was jumbled in among the hundreds we've collected from the site over the years," Flynn said. "It took some time before we could focus on these bones, but once we did, it was clear we had something unique and worth a closer look. This is a great case for why field discoveries -- combined with modern technology to analyze the fossils recovered -- is still so important."
"Discovery of this tiny relative of dinosaurs and pterosaurs emphasizes the importance of Madagascar's fossil record for improving knowledge of vertebrate history during times that are poorly known in other places," said project co-leader Lovasoa Ranivoharimanana, professor and director of the vertebrate paleontology laboratory at the University of Antananarivo in Madagascar. "Over two decades, our collaborative Madagascar-U.S. teams have trained many Malagasy students in paleontological sciences, and discoveries like this helps people in Madagascar and around the world better appreciate the exceptional record of ancient life preserved in the rocks of our country."
Kongonaphon isn't the first small animal known near the root of the ornithodiran family tree, but previously, such specimens were considered "isolated exceptions to the rule," Kammerer noted. In general, the scientific thought was that body size remained similar among the first archosaurs -- the larger reptile group that includes birds, crocodilians, non-avian dinosaurs, and pterosaurs -- and the earliest ornithodirans, before increasing to gigantic proportions in the dinosaur lineage.
"Recent discoveries like Kongonaphon have given us a much better understanding of the early evolution of ornithodirans. Analyzing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage," Kammerer said.
This "miniaturization" event indicates that the dinosaur and pterosaur lineages originated from extremely small ancestors yielding important implications for their paleobiology. For instance, wear on the teeth of Kongonaphon suggests it ate insects. A shift to insectivory, which is associated with small body size, may have helped early ornithodirans survive by occupying a niche different from their mostly meat-eating contemporaneous relatives.
The work also suggests that fuzzy skin coverings ranging from simple filaments to feathers, known on both the dinosaur and pterosaur sides of the ornithodiran tree, may have originated for thermoregulation in this small-bodied common ancestor. That's because heat retention in small bodies is difficult, and the mid-late Triassic was a time of climatic extremes, inferred to have sharp shifts in temperature between hot days and cold nights.
Sterling Nesbitt, an assistant professor at Virginia Tech and a Museum research associate and expert in ornithodiran anatomy, phylogeny, and histological age analyses, is also an author on this study.
Read more at Science Daily
"There's a general perception of dinosaurs as being giants," said Christian Kammerer, a research curator in paleontology at the North Carolina Museum of Natural Sciences and a former Gerstner Scholar at the American Museum of Natural History. "But this new animal is very close to the divergence of dinosaurs and pterosaurs, and it's shockingly small."
Dinosaurs and pterosaurs both belong to the group Ornithodira. Their origins, however, are poorly known, as few specimens from near the root of this lineage have been found. The fossils of Kongonaphon were discovered in 1998 in Madagascar by a team of researchers led by American Museum of Natural History Frick Curator of Fossil Mammals John Flynn (who worked at The Field Museum at the time) in close collaboration with scientists and students at the University of Antananarivo, and project co-leader Andre Wyss, chair and professor of the University of California-Santa Barbara's Department of Earth Science and an American Museum of Natural History research associate.
"This fossil site in southwestern Madagascar from a poorly known time interval globally has produced some amazing fossils, and this tiny specimen was jumbled in among the hundreds we've collected from the site over the years," Flynn said. "It took some time before we could focus on these bones, but once we did, it was clear we had something unique and worth a closer look. This is a great case for why field discoveries -- combined with modern technology to analyze the fossils recovered -- is still so important."
"Discovery of this tiny relative of dinosaurs and pterosaurs emphasizes the importance of Madagascar's fossil record for improving knowledge of vertebrate history during times that are poorly known in other places," said project co-leader Lovasoa Ranivoharimanana, professor and director of the vertebrate paleontology laboratory at the University of Antananarivo in Madagascar. "Over two decades, our collaborative Madagascar-U.S. teams have trained many Malagasy students in paleontological sciences, and discoveries like this helps people in Madagascar and around the world better appreciate the exceptional record of ancient life preserved in the rocks of our country."
Kongonaphon isn't the first small animal known near the root of the ornithodiran family tree, but previously, such specimens were considered "isolated exceptions to the rule," Kammerer noted. In general, the scientific thought was that body size remained similar among the first archosaurs -- the larger reptile group that includes birds, crocodilians, non-avian dinosaurs, and pterosaurs -- and the earliest ornithodirans, before increasing to gigantic proportions in the dinosaur lineage.
"Recent discoveries like Kongonaphon have given us a much better understanding of the early evolution of ornithodirans. Analyzing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage," Kammerer said.
This "miniaturization" event indicates that the dinosaur and pterosaur lineages originated from extremely small ancestors yielding important implications for their paleobiology. For instance, wear on the teeth of Kongonaphon suggests it ate insects. A shift to insectivory, which is associated with small body size, may have helped early ornithodirans survive by occupying a niche different from their mostly meat-eating contemporaneous relatives.
The work also suggests that fuzzy skin coverings ranging from simple filaments to feathers, known on both the dinosaur and pterosaur sides of the ornithodiran tree, may have originated for thermoregulation in this small-bodied common ancestor. That's because heat retention in small bodies is difficult, and the mid-late Triassic was a time of climatic extremes, inferred to have sharp shifts in temperature between hot days and cold nights.
Sterling Nesbitt, an assistant professor at Virginia Tech and a Museum research associate and expert in ornithodiran anatomy, phylogeny, and histological age analyses, is also an author on this study.
Read more at Science Daily
Jul 6, 2020
The sixth sense of animals: An early warning system for earthquakes?
Even today, nobody can reliably predict when and where an earthquake will occur. However, eyewitnesses have repeatedly reported that animals behave unusually before an earthquake. In an international cooperation project, researchers from the Max Planck Institute of Animal Behavior in Konstanz/Radolfzell and the Cluster of Excellence Centre for the Advanced Study of Collective Behaviour at the University of Konstanz, have investigated whether cows, sheep, and dogs can actually detect early signs of earthquakes. To do so, they attached sensors to the animals in an earthquake-prone area in Northern Italy and recorded their movements over several months. The movement data show that the animals were unusually restless in the hours before the earthquakes. The closer the animals were to the epicentre of the impending quake, the earlier they started behaving unusually. The movement profiles of different animal species in different regions could therefore provide clues with respect to the place and time of an impending earthquake.
Experts disagree about whether earthquakes can be exactly predicted. Nevertheless, animals seem to sense the impending danger hours in advance. For example, there are reports that wild animals leave their sleeping and nesting places immediately before strong quakes and that pets become restless. However, these anecdotal accounts often do not stand up to scientific scrutiny because the definition of unusual behaviour is often too unclear and the observation period too short. Other factors could also explain the behaviour of the animals.
In order to be able to use animal activity patterns as a kind of early warning system for earthquakes, the animals would have to show measurable behavioural changes. Moreover, if they do indeed react to weak physical changes immediately before an earthquake, they should react more strongly the closer they are to the epicentre of the quake.
In an international cooperation project, researchers from the Max Planck Institute of Animal Behavior in Radolfzell/Konstanz and the Centre for the Advanced Study of Collective Behaviour, a Cluster of Excellence at the University of Konstanz, have investigated whether animals really do this. On an Italian farm in an earthquake-prone area, they attached accelerometers to the collars of six cows, five sheep, and two dogs that had already displayed unusual behaviour before earthquakes. The researchers then recorded their movements continuously over several months. During this period, official authorities reported about 18,000 earthquakes in the region. In addition to many small and hardly noticeable quakes, there were also 12 earthquakes with a strength of 4 or higher on the Richter scale.
The researchers then selected the quakes that triggered statistically relevant earth movements on the farm. These included strong quakes up to 28 km away as well as weaker quakes, the epicentres of which were very close to the farm. However, instead of explicitly looking for abnormal behaviours in the period before these events, the researchers chose a more cautious approach. They first marked all behavioural changes of the animals that were unusual according to objective, statistical criteria. "In this way, we ensure that we not only establish correlations retrospectively but also that we really do have a model that can be used for predictions," says Martin Wikelski, director at the Max Planck Institute of Animal Behavior and Principal Investigator at the Centre for the Advanced Study of Collective Behaviour.
The data -- measured as body acceleration of each farm animal (indicating activity level) -- were evaluated using statistical models drawn from financial econometrics. "Because every animal reacts differently in size, speed and according to species, the animal data resemble data on heterogenous financial investors," explains co-author Winfried Pohlmeier, Professor of Econometrics at the University of Konstanz and Principal Investigator at the Centre for the Advanced Study of Collective Behaviour. The scientists also considered other disturbance factors such as natural changes in animal activity patterns over the day.
In this way, the researchers discovered unusual behavioural patterns up to 20 hours before an earthquake. "The closer the animals were to the epicentre of the impending shock, the earlier they changed their behaviour. This is exactly what you would expect when physical changes occur more frequently at the epicentre of the impending earthquake and become weaker with increasing distance," explains Wikelski. However, this effect was clear only when the researchers looked at all animals together. "Collectively, the animals seem to show abilities that are not so easily recognized on an individual level," says Wikelski.
It is still unclear how animals can sense impending earthquakes. Animals may sense the ionization of the air caused by the large rock pressures in earthquake zones with their fur. It is also conceivable that animals can smell gases released from quartz crystals before an earthquake.
Real-time data measured by the researchers and recorded since December 2019 show what an animal earthquake early warning system could look like: a chip on the collar sends the movement data to a central computer every three minutes. This triggers a warning signal if it registers a significantly increased activity of the animals for at least 45 minutes.
The researchers have once received such a warning. "Three hours later, a small quake shook the region," says Wikelski. "The epicentre was directly below the stables of the animals."
However, before the behaviour of animals can be used to predict earthquakes, researchers need to observe a larger number of animals over longer periods of time in different earthquake zones around the world. For this, they want to use the global animal observation system Icarus on the International Space Station ISS, which will start its scientific operation in a few weeks.
Read more at Science Daily
Experts disagree about whether earthquakes can be exactly predicted. Nevertheless, animals seem to sense the impending danger hours in advance. For example, there are reports that wild animals leave their sleeping and nesting places immediately before strong quakes and that pets become restless. However, these anecdotal accounts often do not stand up to scientific scrutiny because the definition of unusual behaviour is often too unclear and the observation period too short. Other factors could also explain the behaviour of the animals.
In order to be able to use animal activity patterns as a kind of early warning system for earthquakes, the animals would have to show measurable behavioural changes. Moreover, if they do indeed react to weak physical changes immediately before an earthquake, they should react more strongly the closer they are to the epicentre of the quake.
In an international cooperation project, researchers from the Max Planck Institute of Animal Behavior in Radolfzell/Konstanz and the Centre for the Advanced Study of Collective Behaviour, a Cluster of Excellence at the University of Konstanz, have investigated whether animals really do this. On an Italian farm in an earthquake-prone area, they attached accelerometers to the collars of six cows, five sheep, and two dogs that had already displayed unusual behaviour before earthquakes. The researchers then recorded their movements continuously over several months. During this period, official authorities reported about 18,000 earthquakes in the region. In addition to many small and hardly noticeable quakes, there were also 12 earthquakes with a strength of 4 or higher on the Richter scale.
The researchers then selected the quakes that triggered statistically relevant earth movements on the farm. These included strong quakes up to 28 km away as well as weaker quakes, the epicentres of which were very close to the farm. However, instead of explicitly looking for abnormal behaviours in the period before these events, the researchers chose a more cautious approach. They first marked all behavioural changes of the animals that were unusual according to objective, statistical criteria. "In this way, we ensure that we not only establish correlations retrospectively but also that we really do have a model that can be used for predictions," says Martin Wikelski, director at the Max Planck Institute of Animal Behavior and Principal Investigator at the Centre for the Advanced Study of Collective Behaviour.
The data -- measured as body acceleration of each farm animal (indicating activity level) -- were evaluated using statistical models drawn from financial econometrics. "Because every animal reacts differently in size, speed and according to species, the animal data resemble data on heterogenous financial investors," explains co-author Winfried Pohlmeier, Professor of Econometrics at the University of Konstanz and Principal Investigator at the Centre for the Advanced Study of Collective Behaviour. The scientists also considered other disturbance factors such as natural changes in animal activity patterns over the day.
In this way, the researchers discovered unusual behavioural patterns up to 20 hours before an earthquake. "The closer the animals were to the epicentre of the impending shock, the earlier they changed their behaviour. This is exactly what you would expect when physical changes occur more frequently at the epicentre of the impending earthquake and become weaker with increasing distance," explains Wikelski. However, this effect was clear only when the researchers looked at all animals together. "Collectively, the animals seem to show abilities that are not so easily recognized on an individual level," says Wikelski.
It is still unclear how animals can sense impending earthquakes. Animals may sense the ionization of the air caused by the large rock pressures in earthquake zones with their fur. It is also conceivable that animals can smell gases released from quartz crystals before an earthquake.
Real-time data measured by the researchers and recorded since December 2019 show what an animal earthquake early warning system could look like: a chip on the collar sends the movement data to a central computer every three minutes. This triggers a warning signal if it registers a significantly increased activity of the animals for at least 45 minutes.
The researchers have once received such a warning. "Three hours later, a small quake shook the region," says Wikelski. "The epicentre was directly below the stables of the animals."
However, before the behaviour of animals can be used to predict earthquakes, researchers need to observe a larger number of animals over longer periods of time in different earthquake zones around the world. For this, they want to use the global animal observation system Icarus on the International Space Station ISS, which will start its scientific operation in a few weeks.
Read more at Science Daily
White dwarfs reveal new insights into the origin of carbon in the universe
A new analysis of white dwarf stars supports their role as a key source of carbon, an element crucial to all life, in the Milky Way and other galaxies.
Approximately 90 percent of all stars end their lives as white dwarfs, very dense stellar remnants that gradually cool and dim over billions of years. With their final few breaths before they collapse, however, these stars leave an important legacy, spreading their ashes into the surrounding space through stellar winds enriched with chemical elements, including carbon, newly synthesized in the star's deep interior during the last stages before its death.
Every carbon atom in the universe was created by stars, through the fusion of three helium nuclei. But astrophysicists still debate which types of stars are the primary source of the carbon in our own galaxy, the Milky Way. Some studies favor low-mass stars that blew off their envelopes in stellar winds and became white dwarfs, while others favor massive stars that eventually exploded as supernovae.
In the new study, published July 6 in Nature Astronomy, an international team of astronomers discovered and analyzed white dwarfs in open star clusters in the Milky Way, and their findings help shed light on the origin of the carbon in our galaxy. Open star clusters are groups of up to a few thousand stars, formed from the same giant molecular cloud and roughly the same age, and held together by mutual gravitational attraction. The study was based on astronomical observations conducted in 2018 at the W. M. Keck Observatory in Hawaii and led by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UC Santa Cruz.
"From the analysis of the observed Keck spectra, it was possible to measure the masses of the white dwarfs. Using the theory of stellar evolution, we were able to trace back to the progenitor stars and derive their masses at birth," Ramirez-Ruiz explained.
The relationship between the initial masses of stars and their final masses as white dwarfs is known as the initial-final mass relation, a fundamental diagnostic in astrophysics that integrates information from the entire life cycles of stars, linking birth to death. In general, the more massive the star at birth, the more massive the white dwarf left at its death, and this trend has been supported on both observational and theoretical grounds.
But analysis of the newly discovered white dwarfs in old open clusters gave a surprising result: the masses of these white dwarfs were notably larger than expected, putting a "kink" in the initial-final mass relation for stars with initial masses in a certain range.
"Our study interprets this kink in the initial-final mass relationship as the signature of the synthesis of carbon made by low-mass stars in the Milky Way," said lead author Paola Marigo at the University of Padua in Italy.
In the last phases of their lives, stars twice as massive as our Sun produced new carbon atoms in their hot interiors, transported them to the surface, and finally spread them into the interstellar medium through gentle stellar winds. The team's detailed stellar models indicate that the stripping of the carbon-rich outer mantle occurred slowly enough to allow the central cores of these stars, the future white dwarfs, to grow appreciably in mass.
Analyzing the initial-final mass relation around the kink, the researchers concluded that stars bigger than 2 solar masses also contributed to the galactic enrichment of carbon, while stars of less than 1.5 solar masses did not. In other words, 1.5 solar masses represents the minimum mass for a star to spread carbon-enriched ashes upon its death.
These findings place stringent constraints on how and when carbon, the element essential to life on Earth, was produced by the stars of our galaxy, eventually ending up trapped in the raw material from which the Sun and its planetary system were formed 4.6 billion years ago.
"Now we know that the carbon came from stars with a birth mass of not less than roughly 1.5 solar masses," said Marigo.
Coauthor Pier-Emmanuel Tremblay at University of Warwick said, "One of most exciting aspects of this research is that it impacts the age of known white dwarfs, which are essential cosmic probes to understand the formation history of the Milky Way. The initial-to-final mass relation is also what sets the lower mass limit for supernovae, the gigantic explosions seen at large distances and that are really important to understand the nature of the universe."
Read more at Science Daily
Approximately 90 percent of all stars end their lives as white dwarfs, very dense stellar remnants that gradually cool and dim over billions of years. With their final few breaths before they collapse, however, these stars leave an important legacy, spreading their ashes into the surrounding space through stellar winds enriched with chemical elements, including carbon, newly synthesized in the star's deep interior during the last stages before its death.
Every carbon atom in the universe was created by stars, through the fusion of three helium nuclei. But astrophysicists still debate which types of stars are the primary source of the carbon in our own galaxy, the Milky Way. Some studies favor low-mass stars that blew off their envelopes in stellar winds and became white dwarfs, while others favor massive stars that eventually exploded as supernovae.
In the new study, published July 6 in Nature Astronomy, an international team of astronomers discovered and analyzed white dwarfs in open star clusters in the Milky Way, and their findings help shed light on the origin of the carbon in our galaxy. Open star clusters are groups of up to a few thousand stars, formed from the same giant molecular cloud and roughly the same age, and held together by mutual gravitational attraction. The study was based on astronomical observations conducted in 2018 at the W. M. Keck Observatory in Hawaii and led by coauthor Enrico Ramirez-Ruiz, professor of astronomy and astrophysics at UC Santa Cruz.
"From the analysis of the observed Keck spectra, it was possible to measure the masses of the white dwarfs. Using the theory of stellar evolution, we were able to trace back to the progenitor stars and derive their masses at birth," Ramirez-Ruiz explained.
The relationship between the initial masses of stars and their final masses as white dwarfs is known as the initial-final mass relation, a fundamental diagnostic in astrophysics that integrates information from the entire life cycles of stars, linking birth to death. In general, the more massive the star at birth, the more massive the white dwarf left at its death, and this trend has been supported on both observational and theoretical grounds.
But analysis of the newly discovered white dwarfs in old open clusters gave a surprising result: the masses of these white dwarfs were notably larger than expected, putting a "kink" in the initial-final mass relation for stars with initial masses in a certain range.
"Our study interprets this kink in the initial-final mass relationship as the signature of the synthesis of carbon made by low-mass stars in the Milky Way," said lead author Paola Marigo at the University of Padua in Italy.
In the last phases of their lives, stars twice as massive as our Sun produced new carbon atoms in their hot interiors, transported them to the surface, and finally spread them into the interstellar medium through gentle stellar winds. The team's detailed stellar models indicate that the stripping of the carbon-rich outer mantle occurred slowly enough to allow the central cores of these stars, the future white dwarfs, to grow appreciably in mass.
Analyzing the initial-final mass relation around the kink, the researchers concluded that stars bigger than 2 solar masses also contributed to the galactic enrichment of carbon, while stars of less than 1.5 solar masses did not. In other words, 1.5 solar masses represents the minimum mass for a star to spread carbon-enriched ashes upon its death.
These findings place stringent constraints on how and when carbon, the element essential to life on Earth, was produced by the stars of our galaxy, eventually ending up trapped in the raw material from which the Sun and its planetary system were formed 4.6 billion years ago.
"Now we know that the carbon came from stars with a birth mass of not less than roughly 1.5 solar masses," said Marigo.
Coauthor Pier-Emmanuel Tremblay at University of Warwick said, "One of most exciting aspects of this research is that it impacts the age of known white dwarfs, which are essential cosmic probes to understand the formation history of the Milky Way. The initial-to-final mass relation is also what sets the lower mass limit for supernovae, the gigantic explosions seen at large distances and that are really important to understand the nature of the universe."
Read more at Science Daily
Asthma and allergies more common in teens who stay up late
Teenagers who prefer to stay up late and wake later in the morning are more likely to suffer with asthma and allergies compared to those who sleep and wake earlier, according to a study published in ERJ Open Research. [1]
Asthma symptoms are known to be strongly linked to the body's internal clock, but this is the first study to look at how individual sleep preferences influence asthma risk in teenagers.
Researchers say the study reinforces the importance of sleep timing for teenagers and opens up a new channel of research in to how sleep affects teenagers' respiratory health.
The study was led by Dr Subhabrata Moitra from the division of pulmonary medicine at the University of Alberta, Canada, who carried out the research while at the Barcelona Institute for Global Health, Spain. He said: "Asthma and allergic diseases are common in children and adolescents across the world and the prevalence is increasing. We know some of the reasons for this increase, such as exposure to pollution and tobacco smoke, but we still need to find out more.
"Sleep and the 'sleep hormone' melatonin are known to influence asthma, so we wanted to see if adolescents' preference for staying up late or going to bed early could be involved in their asthma risk."
The study involved 1,684 adolescents living in West Bengal, India, aged 13 or 14 years, who were taking part in the Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study.
Each participant was asked about any wheezing, asthma, or symptoms of allergic rhinitis, such as a runny nose and sneezing. They were asked a series of questions to judge whether they were 'evening types', 'morning types' or in between, such as what time of the evening or night they tend to feel tired, when they would choose to wake up, and how tired they feel first thing in the morning.
Researchers compared the teenagers' symptoms with their sleep preferences, taking into account other factors that are known to affects asthma and allergies, such as where the participants live and whether their family members smoke.
They found that the chance of having asthma was around three times higher in teens who prefer to sleep later compared to those who preferred to sleep earlier. They also found the risk of suffering allergic rhinitis was twice as high in late-sleepers compared to early-sleepers.
Dr Moitra adds: "Our results suggest there's a link between preferred sleep time, and asthma and allergies in teenagers. We can't be certain that staying up late is causing asthma, but we know that the sleep hormone melatonin is often out of sync in late-sleepers and that could, in turn, be influencing teenagers allergic response.
"We also know that children and young people are increasingly exposed to the light from mobile phone, tablets, and other devices, and staying up later at night. It could be that encouraging teenagers to put down their devices and get to bed a little earlier would help decrease the risk of asthma and allergies. That's something that we need to study more."
A second phase of the PERFORMANCE study is scheduled in 2028-29, which means it will be possible to repeat the study with a new group of teenagers to see if there has been any change in teenagers sleeping habits and their respiratory health. Dr Moitra and his team also hope to quantify their findings by taking objective measurements of participants' lung function and sleep time.
Professor Thierry Troosters is President of the European Respiratory Society and was not involved in the research. He said: "We need to know much more about why asthma and allergies are rising in children and teenager and, hopefully, find ways to reduce these conditions.
Read more at Science Daily
Asthma symptoms are known to be strongly linked to the body's internal clock, but this is the first study to look at how individual sleep preferences influence asthma risk in teenagers.
Researchers say the study reinforces the importance of sleep timing for teenagers and opens up a new channel of research in to how sleep affects teenagers' respiratory health.
The study was led by Dr Subhabrata Moitra from the division of pulmonary medicine at the University of Alberta, Canada, who carried out the research while at the Barcelona Institute for Global Health, Spain. He said: "Asthma and allergic diseases are common in children and adolescents across the world and the prevalence is increasing. We know some of the reasons for this increase, such as exposure to pollution and tobacco smoke, but we still need to find out more.
"Sleep and the 'sleep hormone' melatonin are known to influence asthma, so we wanted to see if adolescents' preference for staying up late or going to bed early could be involved in their asthma risk."
The study involved 1,684 adolescents living in West Bengal, India, aged 13 or 14 years, who were taking part in the Prevalence and Risk Factors of Asthma and Allergy-Related Diseases among Adolescents (PERFORMANCE) study.
Each participant was asked about any wheezing, asthma, or symptoms of allergic rhinitis, such as a runny nose and sneezing. They were asked a series of questions to judge whether they were 'evening types', 'morning types' or in between, such as what time of the evening or night they tend to feel tired, when they would choose to wake up, and how tired they feel first thing in the morning.
Researchers compared the teenagers' symptoms with their sleep preferences, taking into account other factors that are known to affects asthma and allergies, such as where the participants live and whether their family members smoke.
They found that the chance of having asthma was around three times higher in teens who prefer to sleep later compared to those who preferred to sleep earlier. They also found the risk of suffering allergic rhinitis was twice as high in late-sleepers compared to early-sleepers.
Dr Moitra adds: "Our results suggest there's a link between preferred sleep time, and asthma and allergies in teenagers. We can't be certain that staying up late is causing asthma, but we know that the sleep hormone melatonin is often out of sync in late-sleepers and that could, in turn, be influencing teenagers allergic response.
"We also know that children and young people are increasingly exposed to the light from mobile phone, tablets, and other devices, and staying up later at night. It could be that encouraging teenagers to put down their devices and get to bed a little earlier would help decrease the risk of asthma and allergies. That's something that we need to study more."
A second phase of the PERFORMANCE study is scheduled in 2028-29, which means it will be possible to repeat the study with a new group of teenagers to see if there has been any change in teenagers sleeping habits and their respiratory health. Dr Moitra and his team also hope to quantify their findings by taking objective measurements of participants' lung function and sleep time.
Professor Thierry Troosters is President of the European Respiratory Society and was not involved in the research. He said: "We need to know much more about why asthma and allergies are rising in children and teenager and, hopefully, find ways to reduce these conditions.
Read more at Science Daily
Owner behavior affects effort and accuracy in dogs' communications
Human communication has evolved mechanisms that can be observed across all cultures and languages, including the use of communication history and the principle of least effort. These two factors enable us to use shared information about the past and present and to conserve energy, making communications as effective and efficient as possible. Given the remarkable sensitivity of dogs to human vocalizations, gestures and gazes, researchers have suggested that 30.000 years of domestication and co-evolution with humans may have caused dogs to develop similar principles of communication -- a theory known as the domestication hypothesis.
On this basis, researchers designed an experiment that would examine the factors influencing the form, effort and success of dog-human interactions in a hidden-object task. Using 30 dog-owner pairs, researchers focused on a communicative behavior called showing, in which dogs gather the attention of a communicative partner and direct it to an external source.
While the owner waited in another room, an experimenter in view of a participating dog hid the dogs` favourite toy in one of four boxes. When the owner entered the room, the dog had to show its owner where the toy had been hidden. If the owner successfully located the toy, the pair were allowed to play as a reward. Participants were tested in two conditions: a close setup which required more precise showing and a distant setup which allowed for showing in a general direction.
The researchers found no evidence to suggest that dogs adhere to the principal of least effort, as they used as much energy in the easier far setup as they did in the more difficult close setup. However, this might have been a result of the owners influence on their dogs' effort. Secondly, dogs were not affected by different communication histories, as they performed similarly and used similar amounts of energy in both setups regardless of which condition they began with. Despite putting in similar amounts of effort, dogs adapted their showing strategies to be more or less precise, depending on the conditions.
The findings indicate that a crucial factor influencing the effort and accuracy of dogs' showing is the behaviour of the dog's owner. Owners who encouraged their dog to show where the toy was hidden increased their dog's showing effort but generally decreased their showing accuracy.
"We've seen in previous studies that if we keep eye contact with the dog or talk in a high-pitched voice, we seem to prompt a 'ready-to-obey attitude' which makes dogs very excited to follow our commands. So when owners asked their dogs 'Is the toy here?' and pointed at the boxes, they might have caused dogs to just show any box," says Melanie Henschel, main author of the study.
Although the researchers found no effects of communication history or the principal of least effort, the current study indicates for the first time that owners can influence their dog's showing accuracy and success.
Read more at Science Daily
On this basis, researchers designed an experiment that would examine the factors influencing the form, effort and success of dog-human interactions in a hidden-object task. Using 30 dog-owner pairs, researchers focused on a communicative behavior called showing, in which dogs gather the attention of a communicative partner and direct it to an external source.
While the owner waited in another room, an experimenter in view of a participating dog hid the dogs` favourite toy in one of four boxes. When the owner entered the room, the dog had to show its owner where the toy had been hidden. If the owner successfully located the toy, the pair were allowed to play as a reward. Participants were tested in two conditions: a close setup which required more precise showing and a distant setup which allowed for showing in a general direction.
The researchers found no evidence to suggest that dogs adhere to the principal of least effort, as they used as much energy in the easier far setup as they did in the more difficult close setup. However, this might have been a result of the owners influence on their dogs' effort. Secondly, dogs were not affected by different communication histories, as they performed similarly and used similar amounts of energy in both setups regardless of which condition they began with. Despite putting in similar amounts of effort, dogs adapted their showing strategies to be more or less precise, depending on the conditions.
The findings indicate that a crucial factor influencing the effort and accuracy of dogs' showing is the behaviour of the dog's owner. Owners who encouraged their dog to show where the toy was hidden increased their dog's showing effort but generally decreased their showing accuracy.
"We've seen in previous studies that if we keep eye contact with the dog or talk in a high-pitched voice, we seem to prompt a 'ready-to-obey attitude' which makes dogs very excited to follow our commands. So when owners asked their dogs 'Is the toy here?' and pointed at the boxes, they might have caused dogs to just show any box," says Melanie Henschel, main author of the study.
Although the researchers found no effects of communication history or the principal of least effort, the current study indicates for the first time that owners can influence their dog's showing accuracy and success.
Read more at Science Daily
Jul 5, 2020
First evidence of snake-like venom glands found in amphibians
Caecilians are limbless amphibians that, to the untrained eye, can be easily mistaken for snakes. Though caecilians are only distantly related to their reptilian cousins, researchers in a study appearing July 3 in the journal iScience describe specialized glands found along the teeth of the ringed caecilian (Siphonops annulatus), which have the same biological origin and possibly similar function to the venom glands of snakes. If further research can confirm that the glands contain venom, caecilians may represent the oldest land-dwelling vertebrate animal with oral venom glands.
Caecilians are peculiar creatures, being nearly blind and using a combination of facial tentacles and slime to navigate their underground tunnels. "These animals produce two types of secretions -- one is found mostly in the tail that is poisonous, while the head produces a mucus to help with crawling through the earth," says senior author Carlos Jared, a biologist and Director of the Structural Biology Lab at the Butantan Institute in São Paulo. "Because caecilians are one of the least-studied vertebrates, their biology is a black box full of surprises."
"It is while examining the mucous glands of the ringed caecilian that I stumbled upon a never before described set of glands closer to the teeth," says first author Pedro Luiz Mailho-Fontana, a post-doctoral student in the Structural Biology Lab at the Butantan Institute.
What Mailho-Fontana found were a series of small fluid-filled glands in the upper and lower jaw, with long ducts that opened at the base of each tooth. Using embryonic analysis, he found that these oral glands originated from a different tissue than the slime and poison glands found in the caecilian's skin. "The poisonous skin glands of the ringed caecilian form from the epidermis, but these oral glands develop from the dental tissue, and this is the same developmental origin we find in the venom glands of reptiles," says Mailho-Fontana. This marks the first time glands of this kind have been found in an amphibian.
Researchers suspect that the ringed caecilian may use the secretions from these snake-like oral glands to incapacitate its prey. "Since caecilians have no arms or legs, the mouth is the only tool they have to hunt," says co-author Marta Maria Antoniazzi, an evolutionary biologist at the Butantan Institute. "We believe they activate their oral glands the moment they bite down, and specialized biomolecules are incorporated into their secretions.
A preliminary chemical analysis of the oral gland secretions of the ringed caecilian found high activity of phospholipase A2, a common protein found in the toxins of venomous animals. "The phospholipase A2 protein is uncommon in non-venomous species, but we do find it in the venom of bees, wasps, and many kinds of reptiles," says Mailho-Fontana. In fact, the biological activity of phospholipase A2 found in the ringed caecilian was higher than what is found in some rattlesnakes. Still, more biochemical analysis is needed to confirm whether the glandular secretions are toxic.
If future work can verify the secretions are toxic, caecilian oral glands could indicate an early evolutionary design of oral venom organs. "Unlike snakes which have few glands with a large bank of venom, the ringed caecilian has many small glands with minor amounts of fluid. Perhaps caecilians represent a more primitive form of venom gland evolution. Snakes appeared in the Cretaceous probably 100 million years ago, but caecilians are far older, being roughly 250 million years old," Jared says.
Read more at Science Daily
Caecilians are peculiar creatures, being nearly blind and using a combination of facial tentacles and slime to navigate their underground tunnels. "These animals produce two types of secretions -- one is found mostly in the tail that is poisonous, while the head produces a mucus to help with crawling through the earth," says senior author Carlos Jared, a biologist and Director of the Structural Biology Lab at the Butantan Institute in São Paulo. "Because caecilians are one of the least-studied vertebrates, their biology is a black box full of surprises."
"It is while examining the mucous glands of the ringed caecilian that I stumbled upon a never before described set of glands closer to the teeth," says first author Pedro Luiz Mailho-Fontana, a post-doctoral student in the Structural Biology Lab at the Butantan Institute.
What Mailho-Fontana found were a series of small fluid-filled glands in the upper and lower jaw, with long ducts that opened at the base of each tooth. Using embryonic analysis, he found that these oral glands originated from a different tissue than the slime and poison glands found in the caecilian's skin. "The poisonous skin glands of the ringed caecilian form from the epidermis, but these oral glands develop from the dental tissue, and this is the same developmental origin we find in the venom glands of reptiles," says Mailho-Fontana. This marks the first time glands of this kind have been found in an amphibian.
Researchers suspect that the ringed caecilian may use the secretions from these snake-like oral glands to incapacitate its prey. "Since caecilians have no arms or legs, the mouth is the only tool they have to hunt," says co-author Marta Maria Antoniazzi, an evolutionary biologist at the Butantan Institute. "We believe they activate their oral glands the moment they bite down, and specialized biomolecules are incorporated into their secretions.
A preliminary chemical analysis of the oral gland secretions of the ringed caecilian found high activity of phospholipase A2, a common protein found in the toxins of venomous animals. "The phospholipase A2 protein is uncommon in non-venomous species, but we do find it in the venom of bees, wasps, and many kinds of reptiles," says Mailho-Fontana. In fact, the biological activity of phospholipase A2 found in the ringed caecilian was higher than what is found in some rattlesnakes. Still, more biochemical analysis is needed to confirm whether the glandular secretions are toxic.
If future work can verify the secretions are toxic, caecilian oral glands could indicate an early evolutionary design of oral venom organs. "Unlike snakes which have few glands with a large bank of venom, the ringed caecilian has many small glands with minor amounts of fluid. Perhaps caecilians represent a more primitive form of venom gland evolution. Snakes appeared in the Cretaceous probably 100 million years ago, but caecilians are far older, being roughly 250 million years old," Jared says.
Read more at Science Daily
Scientific 'red flag' reveals new clues about our galaxy
Figuring out how much energy permeates the center of the Milky Way -- a discovery reported in the July 3 edition of the journal Science Advances -- could yield new clues to the fundamental source of our galaxy's power, said L. Matthew Haffner of Embry-Riddle Aeronautical University.
The Milky Way's nucleus thrums with hydrogen that has been ionized, or stripped of its electrons so that it is highly energized, said Haffner, assistant professor of physics & astronomy at Embry-Riddle and co-author of the Science Advances paper. "Without an ongoing source of energy, free electrons usually find each other and recombine to return to a neutral state in a relatively short amount of time," he explained. "Being able to see ionized gas in new ways should help us discover the kinds of sources that could be responsible for keeping all that gas energized."
University of Wisconsin-Madison graduate student Dhanesh Krishnarao ("DK"), lead author of the Science Advances paper, collaborated with Haffner and UW-Whitewater Professor Bob Benjamin -- a leading expert on the structure of stars and gas in the Milky Way. Before joining Embry-Riddle in 2018, Haffner worked as a research scientist for 20 years at UW, and he continues to serve as principal investigator for the Wisconsin H-Alpha Mapper, or WHAM, a telescope based in Chile that was used for the team's latest study.
To determine the amount of energy or radiation at the center of the Milky Way, the researchers had to peer through a kind of tattered dust cover. Packed with more than 200 billion stars, the Milky Way also harbors dark patches of interstellar dust and gas. Benjamin was taking a look at two decades' worth of WHAM data when he spotted a scientific red flag -- a peculiar shape poking out of the Milky Way's dark, dusty center. The oddity was ionized hydrogen gas, which appears red when captured through the sensitive WHAM telescope, and it was moving in the direction of Earth.
The position of the feature -- known to scientists as the "Tilted Disk" because it looks tilted compared with the rest of the Milky Way -- couldn't be explained by known physical phenomena such as galactic rotation. The team had a rare opportunity to study the protruding Tilted Disk, liberated from its usual patchy dust cover, by using optical light. Usually, the Tilted Disk must be studied with infrared or radio light techniques, which allow researchers to make observations through the dust, but limit their ability to learn more about ionized gas.
"Being able to make these measurements in optical light allowed us to compare the nucleus of the Milky Way to other galaxies much more easily," Haffner said. "Many past studies have measured the quantity and quality of ionized gas from the centers of thousands of spiral galaxies throughout the universe. For the first time, we were able to directly compare measurements from our Galaxy to that large population."
Krishnarao leveraged an existing model to try and predict how much ionized gas should be in the emitting region that had caught Benjamin's eye. Raw data from the WHAM telescope allowed him to refine his predictions until the team had an accurate 3-D picture of the structure. Comparing other colors of visible light from hydrogen, nitrogen and oxygen within the structure gave researchers further clues to its composition and properties.
At least 48 percent of the hydrogen gas in the Tilted Disk at the center of the Milky Way has been ionized by an unknown source, the team reported. "The Milky Way can now be used to better understand its nature," Krishnarao said.
The gaseous, ionized structure changes as it moves away from the Milky Way's center, researchers reported. Previously, scientists only knew about the neutral (non-ionized) gas located in that region.
"Close to the nucleus of the Milky Way," Krishnarao explained, "gas is ionized by newly forming stars, but as you move further away from the center, things get more extreme, and the gas becomes similar to a class of galaxies called LINERs, or low ionization (nuclear) emission regions."
The structure appeared to be moving toward Earth because it was on an elliptical orbit interior to the Milky Way's spiral arms, researchers found.
LINER-type galaxies such as the Milky Way make up roughly a third of all galaxies. They have centers with more radiation than galaxies that are only forming new stars, yet less radiation than those whose supermassive black holes are actively consuming a tremendous amount of material.
"Before this discovery by WHAM, the Andromeda Galaxy was the closest LINER spiral to us," said Haffner. "But it's still millions of light-years away. With the nucleus of the Milky Way only tens of thousands of light-years away, we can now study a LINER region in more detail. Studying this extended ionized gas should help us learn more about the current and past environment in the center of our Galaxy."
Next up, researchers will need to figure out the source of the energy at the center of the Milky Way. Being able to categorize the galaxy based on its level of radiation was an important first step toward that goal.
Now that Haffner has joined Embry-Riddle's growing Astronomy & Astrophysics program, he and his colleague Edwin Mierkiewicz, associate professor of physics, have big plans. "In the next few years, we hope to build WHAM's successor, which would give us a sharper view of the gas we study," Haffner said. "Right now our map `pixels' are twice the size of the full moon. WHAM has been a great tool for producing the first all-sky survey of this gas, but we're hungry for more details now."
Read more at Science Daily
The Milky Way's nucleus thrums with hydrogen that has been ionized, or stripped of its electrons so that it is highly energized, said Haffner, assistant professor of physics & astronomy at Embry-Riddle and co-author of the Science Advances paper. "Without an ongoing source of energy, free electrons usually find each other and recombine to return to a neutral state in a relatively short amount of time," he explained. "Being able to see ionized gas in new ways should help us discover the kinds of sources that could be responsible for keeping all that gas energized."
University of Wisconsin-Madison graduate student Dhanesh Krishnarao ("DK"), lead author of the Science Advances paper, collaborated with Haffner and UW-Whitewater Professor Bob Benjamin -- a leading expert on the structure of stars and gas in the Milky Way. Before joining Embry-Riddle in 2018, Haffner worked as a research scientist for 20 years at UW, and he continues to serve as principal investigator for the Wisconsin H-Alpha Mapper, or WHAM, a telescope based in Chile that was used for the team's latest study.
To determine the amount of energy or radiation at the center of the Milky Way, the researchers had to peer through a kind of tattered dust cover. Packed with more than 200 billion stars, the Milky Way also harbors dark patches of interstellar dust and gas. Benjamin was taking a look at two decades' worth of WHAM data when he spotted a scientific red flag -- a peculiar shape poking out of the Milky Way's dark, dusty center. The oddity was ionized hydrogen gas, which appears red when captured through the sensitive WHAM telescope, and it was moving in the direction of Earth.
The position of the feature -- known to scientists as the "Tilted Disk" because it looks tilted compared with the rest of the Milky Way -- couldn't be explained by known physical phenomena such as galactic rotation. The team had a rare opportunity to study the protruding Tilted Disk, liberated from its usual patchy dust cover, by using optical light. Usually, the Tilted Disk must be studied with infrared or radio light techniques, which allow researchers to make observations through the dust, but limit their ability to learn more about ionized gas.
"Being able to make these measurements in optical light allowed us to compare the nucleus of the Milky Way to other galaxies much more easily," Haffner said. "Many past studies have measured the quantity and quality of ionized gas from the centers of thousands of spiral galaxies throughout the universe. For the first time, we were able to directly compare measurements from our Galaxy to that large population."
Krishnarao leveraged an existing model to try and predict how much ionized gas should be in the emitting region that had caught Benjamin's eye. Raw data from the WHAM telescope allowed him to refine his predictions until the team had an accurate 3-D picture of the structure. Comparing other colors of visible light from hydrogen, nitrogen and oxygen within the structure gave researchers further clues to its composition and properties.
At least 48 percent of the hydrogen gas in the Tilted Disk at the center of the Milky Way has been ionized by an unknown source, the team reported. "The Milky Way can now be used to better understand its nature," Krishnarao said.
The gaseous, ionized structure changes as it moves away from the Milky Way's center, researchers reported. Previously, scientists only knew about the neutral (non-ionized) gas located in that region.
"Close to the nucleus of the Milky Way," Krishnarao explained, "gas is ionized by newly forming stars, but as you move further away from the center, things get more extreme, and the gas becomes similar to a class of galaxies called LINERs, or low ionization (nuclear) emission regions."
The structure appeared to be moving toward Earth because it was on an elliptical orbit interior to the Milky Way's spiral arms, researchers found.
LINER-type galaxies such as the Milky Way make up roughly a third of all galaxies. They have centers with more radiation than galaxies that are only forming new stars, yet less radiation than those whose supermassive black holes are actively consuming a tremendous amount of material.
"Before this discovery by WHAM, the Andromeda Galaxy was the closest LINER spiral to us," said Haffner. "But it's still millions of light-years away. With the nucleus of the Milky Way only tens of thousands of light-years away, we can now study a LINER region in more detail. Studying this extended ionized gas should help us learn more about the current and past environment in the center of our Galaxy."
Next up, researchers will need to figure out the source of the energy at the center of the Milky Way. Being able to categorize the galaxy based on its level of radiation was an important first step toward that goal.
Now that Haffner has joined Embry-Riddle's growing Astronomy & Astrophysics program, he and his colleague Edwin Mierkiewicz, associate professor of physics, have big plans. "In the next few years, we hope to build WHAM's successor, which would give us a sharper view of the gas we study," Haffner said. "Right now our map `pixels' are twice the size of the full moon. WHAM has been a great tool for producing the first all-sky survey of this gas, but we're hungry for more details now."
Read more at Science Daily
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