New species of ‘missing link’ between dinosaurs and birds identified

Dr. John Nudds with Archaeopteryx fossil specimen at the European Synchrotron in Grenoble.

Known as the 'Icon of Evolution' and 'the missing link' between dinosaurs and birds, Archaeopteryx has become one of the most famous fossil discoveries in Palaeontology.

Now, as part of an international team of scientists, researchers at The University of Manchester have identified a new species of Archaeopteryx that is closer to modern birds in evolutionary terms.

Dr John Nudds, from the University's School of Earth and Environmental Sciences, and the team have been re-examining one of the only 12 known specimens by carrying out the first ever synchrotron examination, a form of 3D X-ray analysis, of an Archaeopteryx.

Thanks to this new insight, the team says that this individual Archaeopteryx fossil, known as 'specimen number eight', is physically much closer to a modern bird than it is to a reptile. Therefore, it is evolutionary distinctive and different enough to be described as a new species -- Archaeopteryx albersdoerferi.

The research, which is being published in journal Historical Biology, says that some of the differing skeletal characteristics of Archaeopteryx albersdoerferi include the fusion of cranial bones, different pectoral girdle (chest) and wing elements, and a reinforced configuration of carpals and metacarpals (hand) bones.

These characteristics are seen more in modern flying birds and are not found in the older Archaeopteryx lithographica species, which more resembles reptiles and dinosaurs.

Specimen number eight is the youngest of all the 12 known specimens by approximately half a million years. This age difference in comparison to the other specimens is a key factor in describing it as a new species.

Dr Nudds explains: "By digitally dissecting the fossil we found that this specimen differed from all of the others. It possessed skeletal adaptations which would have resulted in much more efficient flight. In a nutshell we have discovered what Archaeopteryx lithographica evolved into -- i.e. a more advanced bird, better adapted to flying -- and we have described this as a new species of Archaeopteryx."

Archaeopteryx was first described as the 'missing link' between reptiles and birds in 1861 -- and is now regarded as the link between dinosaurs and birds. Only 12 specimens have ever been found and all are from the late Jurassic of Bavaria, now Germany, dating back approximately 150 million years.

Lead author, Dr Martin Kundrát, from the University of Pavol Jozef Šafárik, Slovakia, said: "This is the first time that numerous bones and teeth of Archaeopteryx were viewed from all aspects including exposure of their inner structure. The use of synchrotron microtomography was the only way to study the specimen as it is heavily compressed with many fragmented bones partly or completely hidden in limestone."

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Just a few drinks can change how memories are formed

Studying fruit flies, researchers at Brown University found that alcohol hijacks a conserved memory pathway in the brain, forming the cravings that fuel addiction. The pink areas are the fly's memory centers and the green dots are where the first molecular signaling "domino" Notch has been activated.

One of the many challenges with battling alcohol addiction and other substance abuse disorders is the risk of relapse, even after progress toward recovery. Even pesky fruit flies have a hankering for alcohol, and because the molecular signals involved in forming flies' reward and avoidance memories are much the same as those in humans, they're a good model for study.

A new study in flies finds that alcohol hijacks this memory formation pathway and changes the proteins expressed in the neurons, forming cravings. Just a few drinks in an evening changes how memories are formed at the fundamental, molecular level.

The findings were published on Thursday, Oct. 25, in the journal Neuron.

Karla Kaun, assistant professor of neuroscience at Brown University and senior author on the paper, worked with a team of undergraduates, technicians and postdoctoral researchers to uncover the molecular signaling pathways and changes in gene expression involved in making and maintaining reward memories.

"One of the things I want to understand is why drugs of abuse can produce really rewarding memories when they're actually neurotoxins," said Kaun, who is affiliated with Brown's Carney Institute for Brain Science. "All drugs of abuse -- alcohol, opiates, cocaine, methamphetamine -- have adverse side effects. They make people nauseous or they give people hangovers, so why do we find them so rewarding? Why do we remember the good things about them and not the bad? My team is trying to understand on a molecular level what drugs of abuse are doing to memories and why they're causing cravings."

Once researchers understand what molecules are changing when cravings are formed, then they can figure out how to help recovering alcoholics and addicts by perhaps decreasing how long the craving memories last, or how intense they are, Kaun said.

Molecular manipulation

Fruit flies have only 100,000 neurons, while humans have more than 100 billion. The smaller scale -- plus the fact that generations of scientists have developed genetic tools to manipulate the activity of these neurons at the circuit and molecular level -- made the fruit fly the perfect model organism for Kaun's team to tease apart the genes and molecular signaling pathways involved in alcohol reward memories, she said.

Led by postdoctoral researcher Emily Petruccelli, who is now an assistant professor with her own lab at Southern Illinois University, the team used genetic tools to selectively turn off key genes while training the flies where to find alcohol. This enabled them to see what proteins were required for this reward behavior.

One of the proteins responsible for the flies' preference for alcohol is Notch, the researchers found. Notch is the first "domino" in a signaling pathway involved in embryo development, brain development and adult brain function in humans and all other animals. Molecular signaling pathways are not unlike a cascade of dominos -- when the first domino falls (in this case, the biological molecule activates), it triggers more that trigger more and so on.

One of the downstream dominos in the signaling pathway affected by alcohol is a gene called dopamine-2-like receptor, which makes a protein on neurons that recognizes dopamine, the "feel-good" neurotransmitter.

"The dopamine-2-like receptor is known to be involved in encoding whether a memory is pleasing or aversive," Petruccelli said. And alcohol hijacks this conserved memory pathway to form cravings.

In the case of the alcohol reward pathway studied, the signaling cascade didn't turn the dopamine receptor gene on or off, or increase or decrease the amount of protein made, Kaun said. Instead, it had a subtler effect -- it changed the version of the protein made by a single amino acid "letter" in an important area.

"We don't know what the biological consequences of that small change are, but one of the important findings from this study is that scientists need to look not only at which genes are being turned on and off, but which forms of each gene are getting turned on and off," Kaun said. "We think these results are highly likely to translate to other forms of addiction, but nobody has investigated that."

The team is continuing its work by studying the effects that opiates have on the same conserved molecular pathways. Additionally, Kaun is working with John McGeary, assistant professor of psychiatry and human behavior at Brown, to look at DNA samples from patients with alcohol abuse disorders to see if they have genetic polymorphisms in any of the craving-related genes discovered in flies.

"If this works the same way in humans, one glass of wine is enough to activate the pathway, but it returns to normal within an hour," Kaun said. "After three glasses, with an hour break in between, the pathway doesn't return to normal after 24 hours. We think this persistence is likely what is changing the gene expression in memory circuits.

"Just something to keep in mind the next time you split a bottle of wine with a friend or spouse," she added.

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How the brain decides what to learn

Assistant Professor Xiaoke Chen, right, discusses the functions of the paraventricular thalamus with researcher Greg Nachtrab, one of his co-authors on a new paper.

In order to learn about the world, an animal needs to do more than just pay attention to its surroundings. It also needs to learn which sights, sounds and sensations in its environment are the most important and monitor how the importance of those details change over time. Yet how humans and other animals track those details has remained a mystery.

Now, Stanford biologists report Oct. 26 in Science, they think they've figured out how animals sort through the details. A part of the brain called the paraventricular thalamus, or PVT, serves as a kind of gatekeeper, making sure that the brain identifies and tracks the most salient details of a situation. Although the research, funded in part by the Wu Tsai Neuroscience Institute's Neurochoice Initiative, is confined to mice for now, the results could one day help researchers better understand how humans learn or even help treat drug addiction, said senior author Xiaoke Chen, an assistant professor of biology.

The results are a surprise, Chen said, in part because few had suspected the thalamus could do something so sophisticated. "We showed thalamic cells play a very important role in keeping track of the behavioral significance of stimuli, which nobody had done before," said Chen, who is also a member of Stanford Bio-X and the Wu Tsai Neurosciences Institute.

Deciding what to learn

In its most basic form, learning comes down to feedback. For example, if you have a headache and take a drug, you expect the drug will make your headache go away. If you're right, you'll take that drug the next time you have a headache. If you're wrong, you'll try something else. Psychologists and neuroscientists have studied this aspect of learning extensively and even traced it to specific parts of the brain that process feedback and drive learning.

Still, that picture of learning is incomplete, Chen said. Even in relatively uncomplicated laboratory experiments, let alone life in the real world, humans and other animals need to figure out what to learn from -- essentially, what's feedback and what's noise. Despite that need, it's an issue psychologists and neuroscientists have not paid as much attention to.

To start to remedy that, Chen and colleagues taught mice to associate particular odors with good and bad outcomes. One odor signaled a sip of water was coming, while another signaled the mouse was about to get a puff of air to the face.

Later, the researchers replaced the air puff with a mild electric shock -- something that would presumably command a bit more attention. The team found that neurons in the PVT tracked that change. During the air-puff phase, two-thirds of PVT neurons responded to both odors while an additional 30 percent were activated only by the odor signaling water. In other words, during this phase the PVT responded to both good and bad outcomes, but there was greater response to good.

During the electric-shock phase, however, the balance shifted. Almost all PVT neurons responded to the shock, while about three quarters of them responded to both good and bad outcomes.

A similar shift happened when mice had had their fill of water. Now that water mattered less to the mice, the PVT was less responsive to water and more responsive to air puffs, meaning it became more responsive to bad outcomes and less so to good ones. Taken together, the results showed the PVT tracks what was most important in the moment -- the good outcome when that outweighed the bad, and vice versa.

A new place to look, and to tweak

The results point to several broader conclusions, Chen said. Perhaps most important, other researchers now have a place to look -- the PVT -- when they want to study how paying attention to different details affects how and what animals learn.

Neuroscientists also now have a new way to control learning, Chen said. In additional experiments with mice genetically modified so the team could control PVT activity with light, the researchers found they could inhibit or enhance learning -- for example, they could more quickly teach mice that an odor no longer reliably signaled water was coming, or that another odor had switched from signaling water to signaling a shock.

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Mind’s quality control center found in long-ignored brain area

Model of the brain

The cerebellum can't get no respect. Located inconveniently on the underside of the brain and initially thought to be limited to controlling movement, the cerebellum has long been treated like an afterthought by researchers studying higher brain functions.

But researchers at Washington University School of Medicine in St. Louis say overlooking the cerebellum is a mistake. Their findings, published Oct. 25 in Neuron, suggest that the cerebellum has a hand in every aspect of higher brain functions -- not just movement, but attention, thinking, planning and decision-making.

"The biggest surprise to me was the discovery that 80 percent of the cerebellum is devoted to the smart stuff," said senior author Nico Dosenbach, MD, PhD, an assistant professor of neurology, of occupational therapy and of pediatrics. "Everyone thought the cerebellum was about movement. If your cerebellum is damaged, you can't move smoothly -- your hand jerks around when you try to reach for something. Our research strongly suggests that just as the cerebellum serves as a quality check on movement, it also checks your thoughts as well -- smoothing them out, correcting them, perfecting things."

Dosenbach is a founding member of the Midnight Scan Club, a group of Washington University neuroscientists who have taken turns in an MRI scanner late at night, scanning their own brains for hours to generate a massive amount of high-quality data for their research. A previous analysis of Midnight Scan Club data showed that a kind of brain scan called functional connectivity MRI can reliably detect fundamental differences in how individual brains are wired.

Postdoctoral researcher and first author Scott Marek, PhD, decided to apply a similar analysis to the cerebellum. In the better-known cerebral cortex -- the crumpled outer layer of the brain -- wiring maps have been drawn that connect distant areas into networks that govern vision, attention, language and movement. But nobody knew how the cerebellum is organized in individuals, partly because a quirk of MRI technology means that data obtained from the underside of the brain tend to be low quality. In the Midnight Scan Club dataset, however, Marek had access to more than 10 hours of scans on each of 10 people, enough to take a serious look at the cerebellum.

Using the cortex's networks as a template, Marek could identify the networks in the cerebellum. Notably, the sensory networks are missing -- vision, hearing and touch -- and only 20 percent of the cerebellum is devoted to movement, roughly the same amount as in the cerebral cortex. The remaining 80 percent is occupied by networks involved in higher-order cognition: the attention network; the default network, which has to do with daydreaming, recalling memories and just idly thinking; and two networks that oversee executive functions such as decision-making and planning.

"The executive function networks are way overrepresented in the cerebellum," Marek said. "Our whole understanding of the cerebellum needs to shift away from it being involved in motor control to it being more involved in general control of higher-level cognition."

The researchers measured the timing of brain activity and found that the cerebellum was consistently the last step in neurologic circuits. Signals were received through sensory systems and processed in intermediate networks in the cerebral cortex before being sent to the cerebellum. There, the researchers surmise, the signals undergo final quality checks before the output is sent back to the cerebral cortex for implementation.

"If you think of an assembly line, the cerebellum is the person at the end who inspects the car and says, 'This one is good; we'll sell it,' or 'This one has a dent; we have to go back and repair it,'" Dosenbach said. "It's where all your thoughts and actions get refined and quality controlled."

People with damage to their cerebellum are known to become uncoordinated, with an unsteady gait, slurred speech and difficulty with fine motor tasks such as eating. The cerebellum also is quite sensitive to alcohol, which is one of the reasons why people who have had too many drinks stumble around. But the new data may help explain why someone who is inebriated also shows poor judgment. Just as a person staggers drunkenly because his or her compromised cerebellum is unable to perform the customary quality checks on motor function, alcohol-fueled bad decisions might also reflect a breakdown of quality control over executive functions.

Marek also performed individualized network analyses on the 10 people in the data set. He found that while brain functions are arranged in roughly the same pattern in everyone's cerebellum, there is enough individual variation to distinguish brain scans performed on any two participants. The researchers are now investigating whether such individual differences in cerebellar networks correlate with intelligence, behavior, personality traits such as adaptability, or psychiatric conditions.

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Artificial fly brain can tell who's who

A) An ideal fruit fly input. B) Traditional view. C) Updated view.

Despite the simplicity of their visual system, fruit flies are able to reliably distinguish between individuals based on sight alone. This is a task that even humans who spend their whole lives studying Drosophila melanogaster struggle with. Researchers have now built a neural network that mimics the fruit fly's visual system and can distinguish and re-identify flies. This may allow the thousands of labs worldwide that use fruit flies as a model organism to do more longitudinal work, looking at how individual flies change over time. It also provides evidence that the humble fruit fly's vision is clearer than previously thought.

In an interdisciplinary project funded by a Canadian Institute for Advanced Research (CIFAR) Catalyst grant, researchers at the University of Guelph and the University of Toronto, Mississauga combined expertise in fruit fly biology with machine learning to build a biologically-based algorithm that churns through low-resolution videos of fruit flies in order to test whether it is physically possible for a system with such constraints to accomplish such a difficult task.

Fruit flies have small compound eyes that take in a limited amount of visual information, an estimated 29 units squared. The traditional view has been that once the image is processed by a fruit fly, it is only able to distinguish very broad features. But a recent discovery that fruit flies can boost their effective resolution with subtle biological tricks has led researchers to believe that vision could contribute significantly to the social lives of flies. This, combined with the discovery that the structure of their visual system looks a lot like a Deep Convolutional Network (DCN), led the team to ask: "can we model a fly brain that can identify individuals?"

Their computer program has the same theoretical input and processing ability as a fruit fly and was trained on video of a fly over two days. It was then able to reliably identify the same fly on the third day with an F1 score (a measure that combines precision and recall) of 0.75. Impressively, this is only slightly worse than scores of 0.85 and 0.83 for algorithms without the constraints of fly-brain biology. For comparison, when given the easier task of matching the 'mugshot' of a fly to a field of 20 others, experienced human fly biologists only managed a score of 0.08. Random chance would score 0.05.

According to Jon Schneider, the first author of the paper being published in PLOS ONE this week, this study points to "the tantalizing possibility that rather than just being able to recognize broad categories, fruit flies are able to distinguish individuals. So when one lands next to another, it's "Hi Bob, Hey Alice." "

Graham Taylor, a machine learning specialist and CIFAR Azrieli Global Scholar in the Learning in Machines and Brains program, was excited by the prospect of beating humans at a visual task. "A lot of Deep Neural Network applications try to replicate and automate human abilities like facial recognition, natural language processing, or song identification. But rarely do they go beyond human capacity. So it's exciting to find a problem where algorithms can outperform humans."

The experiments took place in the University of Toronto Mississauga lab of Joel Levine, a senior fellow in the CIFAR Child & Brain Development program. He has high hopes for the future of research like this. "The approach of pairing deep learning models with nervous systems is incredibly rich. It can tell us about the models, about how neurons communicate with each other, and it can tell us about the whole animal. That's sort of mind blowing. And it's unexplored territory."

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Tracing the evolutionary origins of fish to shallow ocean waters

Reef fish

The first vertebrates on Earth were fish, and scientists believe they first appeared around 480 million years ago. But fossil records from this time are spotty, with only small fragments identified. By 420 million years ago, however, the fossil record blossoms, with a huge variety of fish species present en masse.

"It's been this ongoing question of, well, where were they?" says Lauren Sallan, a paleobiologist at the University of Pennsylvania. "Where were they hiding? What were their environmental origins?"

Sallan Ivan J. Sansom of the University of Birmingham and colleagues are the first to present a wealth of evidence to answer that question in a report out this week in the journal Science.

And the answer, it seems, is near shore, the areas often describe as the intertidal zone, or shallow lagoons.

"In modern conceptions, we see that coral reefs are so important for fish biodiversity, so we assume there's an ancient link between fishes and reefs going back to the beginning," says Sallan. "But decades of searching in places like the Cincinnati Arch have come up empty."

"Instead, our work shows that almost every major vertebrate division, from the earliest armored jawless fish all the way up through sharks and our own ancestors, all started out right near the beach, far inshore of the reef. Even as older groups spread out, newer groups were also appearing at the shoreline."

The findings help explain important features of the fossil record, such as why so few early fish fossils are found intact; the wave action of the shallow ocean area likely blasted them into tiny fragments. It also helps scientists make sense of the fact that, over evolutionary time, many fish groups moved from ocean water to freshwater with some becoming freshwater fish while others evolved into the earliest tetrapods, land-dwelling vertebrates.

"They often went to freshwater before the reefs, which is almost an independent line of evidence that they would have had to have been close to shore before doing so," Sallan says.

Exactly where vertebrates originated and diversified has been a hotly debated subject in paleontology. Certain groups of fossils from this key period in the middle Paleozoic Era told one story -- perhaps a freshwater site of origin -- while other groups may point to a birthplace in the open ocean, and still others popped up in other habitat types. Further complicating matters, the origin story of invertebrate biodiversity seem settled: They diversified around coral reefs, their descendants subsequently striking out to inhabit shallower or deeper waters.

Sallan, Sansom, and colleagues decided to investigate the question for vertebrates using a big-data approach.

"The nice thing about the fossil record is that we often find fishes in the context of where they live," Sallan says. "The rock that holds them tells us what their environment looked like, whether it was reef, shallow water, deep water, a riverbed, or a lake."

Bringing that environmental context together with what was already known about the family tree relationships of vertebrates from the middle Paleozoic, 480 to 360 million years ago, the researchers created a database that involved 2,728 early records for jawed and jawless fishes.

"It's a really huge new dataset," says Sallan.

The team was then able to reconstruct the missing information in the fossil record using mathematical modeling, allowing them to make informed predictions about the habitat type in which the earliest ancestors of various vertebrate groups emerged.

"For vertebrates, we find that they're originating in this unexpected, really restricted shallow area of the oceans," Sallan says. "And they stay in this limited area for a long time after they emerge."

As they remained in the shallows, however, they gained a variety of adaptations that enabled them to compete with the others in a shared habitat. The researchers noted that many groups acquired traits that made them well-suited for life either as bottom-dwellers, or for a free-swimming ecology out in the ocean's deeper waters.

A similar divergence has been seen in modern fish, such as sticklebacks, which evolved a bottom-dwelling and a free-swimming form from common ancestors in more recent times.

No one has done a similarly comprehensive study on living vertebrate species, however. "One of the things we want to know is whether these shallow waters are still the biological pump that is feeding the reef," Sallan says. "Where is the current site of innovation?"

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Birds startled by moving sticks

The objects used in this research.

Do animals -- like humans -- divide the world into things that move and things that don't? Are they surprised if an apparently inanimate object jumps to life?

Yes -- according to scientists at the universities of Exeter and Cambridge.

The researchers tested how jackdaws responded to moving birds, moving snakes and moving sticks -- and found they were most cautious of the moving sticks.

The study, using remote-controlled objects placed in jackdaws' nests, will help scientists understand how birds perceive potential threats.

"Although as humans we see the divide between animate an inanimate objects as an intuitive one, we've had very little evidence that wild animals also see the world this way," said lead author Dr Alison Greggor, formerly of the University of Cambridge and now at the San Diego Zoo Institute for Conservation Research.

"Laboratory studies have shown that human infants and a few other species discriminate between animate and inanimate objects.

"This ability is assumed to have evolved to support social interactions, but its role for wild animals has never been examined.

"Our work extends the potential function of this ability beyond the social realm. It might therefore be a more common ability than previously thought."

By placing remote-controlled objects in jackdaws' nests, the researchers tested how the birds assessed possible threats to their offspring.

Jackdaws were startled by any movement, producing alarm calls, but they delayed longest in entering their nest box after encountering an "inanimate" object that moved (ie the remote controlled stick).

This suggests they recognised the movement as unexpected and delayed entering the nest in order to gather more information about the situation.

Dr Alex Thornton, of the Centre for Ecology and Conversation on the University of Exeter's Penryn Campus in Cornwall, added: "There is still a great deal we do not understand about some of our common bird species.

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Cacao analysis dates the dawn of domesticated chocolate trees to 3,600 years ago

Researchers analyzing the genomes of cultivated cacao trees have traced their origin to a "single domestication event" some 3,600 years ago. The discovery opens a new front in a long-running argument regarding when and where humans started growing the source of chocolate.

"This evidence increases our understanding of how humans moved and established in America," said Omar Cornejo, a Washington State University population geneticist and lead author of an article on the study in Communications Biology, an open-access journal from the publishers of Nature. "It is important in itself because it gives us a timeframe for asking questions that are perhaps trickier: How long did it take to make a good cacao? How strong was the process of domestication? How many plants were necessary to domesticate a tree?"

The study, which involved 18 scientists from 11 institutions, also found that cacao's domestication ended up selecting for flavor, disease resistance and the stimulant theobromine. However, that came at the cost of retaining genes that lowered crop yields.

Researchers sequenced the Theobroma cacao genome in 2010. That laid out what Cornejo refers to as an archetype of the cacao genome, while this study, by sequencing 200 plants, teases out variations in the genome that can reveal the plant's evolutionary history.

The researchers looked at "the prince of cocoas," Criollo -- rare, flavorful and the first to be domesticated. They found that it was domesticated in Central America 3,600 years ago, but originated in the Amazon basin, near the modern-day border of southern Colombia and northern Ecuador, from an ancient germplasm known as Curaray. Chances are it was introduced to Central America by traders, said Cornejo.

The tree's population at the time consisted of between 437 and 2,674 individual trees, and most likely about 738 trees. The time of domestication 3,600 years ago, with margins of 2,481 and 10,903 years ago, is consistent with traces of theobromine found in Olmec pottery and large-scale analyses of ancient and modern human DNA that put colonization of the Americas at roughly 13,000 years ago.

The researchers also saw support for a hypothesis that domestication carries a cost as growers, in choosing plants with desirable traits, can ultimately make plants that accumulate counterproductive genes -- "deleterious mutations" -- making them less fit.

Insights from the study could help identify genes behind specific traits that breeders can emphasize, including yield.

"What we would like to have is a way to combine plants from populations with high productivity -- like Iquitos -- with plants of Criollo origin, while retaining all these desirable traits that make Criollo cacao be the best in the world," said Cornejo.

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Crater from asteroid that killed the dinosaurs reveals how broken rocks can flow like liquid

A mile-long sediment core drilled by the International Ocean Discovery Program helped researchers uncover how the Chicxulub crater formed.

Sixty-six million years ago, an asteroid the size of a small city smashed into Earth. This impact, the one that would lead to the end of the dinosaurs, left a scar several miles underground and more than 115 miles wide.

Chicxulub, which lies underneath the Yucatán Peninsula of Mexico, is the best-preserved large impact crater on Earth, although it's buried underneath a half mile of rocks. It's also the only crater on the planet with a mountainous ring of smashed rocks inside its outer rim, called a peak ring. How these features form has long been debated, but a new study in Nature shows they're a product of extremely strong vibrations that let rock flow like liquid for a crucial few minutes after the impact.

When an asteroid crashes into Earth, it leaves a bowl-shaped pit, just like you'd expect. But it doesn't just leave a dent. If the asteroid is big enough, the resulting crater can be more than 20 miles deep, at which point it becomes unstable and collapses.

"For a while, the broken rock behaves as a fluid," said Jay Melosh, a professor of earth, atmospheric and planetary sciences at Purdue University. "There have been a lot of theories proposed about what mechanism allows this fluidization to happen, and now we know it's really strong vibrations shaking the rock constantly enough to allow it to flow."

This mechanism, known as "acoustic fluidization," is the process that allows the ring of mountains in the crater's center to rise within minutes of the asteroid's strike. (This idea was first proposed by Melosh in 1979). Craters are essentially the same on all the terrestrial planets (Earth, Mercury, Venus, Mars and our moon), but they're hard to study in space for obvious reasons: We can't look at them with the same detail we can on Earth.

The Chicxulub crater isn't easily accessible by traditional standards either; it's been buried throughout the last 66 million years. So the International Ocean Discovery Program (a group within the International Continental Scientific Drilling Program), did the only thing they could -- they dug. The team drilled a core roughly six inches in diameter and a mile into Earth, collecting rock that was shattered and partly melted by the impact that wiped out the dinosaurs.

In examining fracture zones and patterns in the core, the international research team found an evolution in the vibration sequence that would allow debris to flow.

"These findings help us understand how impact craters collapse and how large masses of rock behave in a fluid-like manner in other circumstances, such as landslides and earthquakes," Melosh said. "Towns have been wiped out by enormous landslides, where people thought they were safe but then discovered that rock will flow like liquid when some disturbance sets a big enough mass in motion."

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A first 'snapshot' of the complete spectrum of neutrinos emitted by the sun

The Borexino instrument located deep beneath Italy's Appenine Mountains detects neutrinos as they interact with the electrons of an ultra-pure organic liquid scintillator at the center of a large sphere surrounded by 1,000 tons of water.

About 99 percent of the Sun's energy emitted as neutrinos is produced through nuclear reaction sequences initiated by proton-proton (pp) fusion in which hydrogen is converted into helium, say scientists including physicist Andrea Pocar at the University of Massachusetts Amherst. Today they report new results from Borexino, one of the most sensitive neutrino detectors on the planet, located deep beneath Italy's Apennine Mountains.

"Neutrinos emitted by this chain represent a unique tool for solar and neutrino physics," they explain. Their new paper in Nature reports on "the first complete study of all the components of the pp-chain performed by Borexino." These components include not only the pp neutrinos, but others called Beryllium-7 (7Be), pep and Boron-8 (8B) neutrinos. The pp fusion reaction of two protons to produce deuteron, nuclei of deuterium, is the first step of a reaction sequence responsible for about 99 percent of the Sun's energy output, Pocar says.

He adds, "What's new today is incremental, it's not a leap, but it is the crowning of more than 10 years of data-taking with the experiment to show the full energy spectrum of the Sun at once. Our results reduce uncertainty, which is perhaps not flashy but it's type of advance that is often not recognized enough in science. The value is that measurements get more precise because with more data and thanks to the work of dedicated young physicists, we have a better understanding of the experimental apparatus."

"Borexino offers the best measurement ever made for the pp, 7Be and pep neutrinos," he adds. "Other experiments measure the 8B neutrinos more precisely, but our measurement, with a lower threshold, is consistent with them."

Further, "Once you have more precise data, you can feed it back into the model of how the Sun is behaving, then the model can be refined even more. It all leads to understanding the Sun better. Neutrinos have told us how the Sun is burning and, in turn, the Sun has provided us with a unique source to study how neutrinos behave. Borexino, scheduled to run for another two to three years, has strengthened our understanding of the Sun very profoundly."

For earlier studies of pp, 7B, pep and 8B neutrinos, the team had focused on each one separately in targeted analyses of the collected data in restricted windows of energy, "like trying to characterize a forest by taking one picture each of many individual types of trees," Pocar notes. "Multiple pictures give you an idea of a forest, but it's not the same as the photo of the entire forest."

"What we have done now is take a single photo that reflects the whole forest, the whole spectrum of all the different neutrinos in one. Instead of zooming in to look at little pieces, we see it all at once. We understand our detector so well now, we are comfortable and confident that our one shot is valid for the whole spectrum of neutrino energies."

Solar neutrinos stream out of the star at the center of our system at nearly the speed of light, as many as 420 billion hitting every square inch of Earth's surface per second. But because they only interact through the nuclear weak force, they pass through matter virtually unaffected, which makes them very difficult to detect and distinguish from trace nuclear decays of ordinary materials, Pocar says.

The Borexino instrument detects neutrinos as they interact with the electrons of an ultra-pure organic liquid scintillator at the center of a large sphere surrounded by 1,000 tons of water. Its great depth and many onion-like protective layers maintain the core as the most radiation-free medium on the planet. It is the only detector on Earth capable of observing the entire spectrum of solar neutrino simultaneously, which has now been accomplished, he notes.

The UMass Amherst physicist, one principal investigator on a team of more than 100 scientists, is particularly interested in now turning his focus to measure yet another type of solar neutrino known as CNO neutrinos, which he hopes will be useful in addressing an important open question in stellar physics, that is the metallicity, or metal content, of the Sun.

"There are two models that predict different levels of elements heavier than helium, which for astronomers is a metal, in the Sun; a lighter metallicity and a heavier model," he notes. CNO neutrinos are emitted in a cyclic fusion reaction sequence different from the pp chain and subdominant in the Sun, but thought to be the main source of power for heavier stars. The CNO solar neutrino flux is greatly affected by the solar metallicity.

Pocar says, "Our data is possibly showing some slight preference for heavy metallicity, so we'll be looking into that because neutrinos from the Sun, especially CNO, can help us disentangle this."

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Astronomers spot signs of supermassive black hole mergers

Jets from double black holes change direction continuously. The effect can explain features in this 5 GHz radio map of 3C 334 and many powerful radio sources in the sky. The jet emanates from the nucleus of a galaxy (its stars are not visible at radio frequencies) about 10 billion light years from our own. The image spans five million light years from left to right. The peculiar structure of the jets signifies a periodic change of the direction of the jet (precession), an effect that is predicted for jets from black hole pairs. The inset diagram schematically illustrates the physical processes in the black hole pair. Jets may form in gas discs around black holes. The direction of the jets is tied to the spin of the black hole. The spin axis is shown as a red arrow. The latter changes direction periodically due to the presence of the second black hole.

New research, published today (Wednesday 24 October) in the journal Monthly Notices of the Royal Astronomical Society, has found evidence for a large number of double supermassive black holes, likely precursors of gigantic black hole merging events. This confirms the current understanding of cosmological evolution -- that galaxies and their associated black holes merge over time, forming bigger and bigger galaxies and black holes.

Astronomers from the University of Hertfordshire, together with an international team of scientists, have looked at radio maps of powerful jet sources and found signs that would usually be present when looking at black holes that are closely orbiting each other.

Before black holes merge they form a binary black hole, where the two black holes orbit around each other. Gravitational wave telescopes have been able to evidence the merging of smaller black holes since 2015, by measuring the strong bursts of gravitational waves that are emitted when binary black holes merge, but current technology cannot be used to demonstrate the presence of supermassive binary black holes.

Supermassive black holes emit powerful jets. When supermassive binary black holes orbit it causes the jet emanating from the nucleus of a galaxy to periodically change its direction. Astronomers from the University of Hertfordshire studied the direction that these jets are emitted in, and variances in these directions; they compared the direction of the jets with the one of the radio lobes (that store all the particles that ever went through the jet channels) to demonstrate that this method can be used to indicate the presence of supermassive binary black holes.

Dr Martin Krause, lead author and senior lecturer in Astronomy at the University of Hertfordshire, said: "We have studied the jets in different conditions for a long time with computer simulations. In this first systematic comparison to high-resolution radio maps of the most powerful radio sources, we were astonished to find signatures that were compatible with jet precession in three quarters of the sources."

The fact that the most powerful jets are associated with binary black holes could have important consequences for the formation of stars in galaxies; stars form from cold gas, jets heat this gas and thus suppress the formation of stars. A jet that always heads in the same direction only heats a limited amount of gas in its vicinity. However, jets from binary black holes change direction continuously. Therefore, they can heat much more gas, suppressing the formation of stars much more efficiently, and thus contributing towards keeping the number of stars in galaxies within the observed limits.

From Science Daily

Gravitational waves could soon accurately measure universe's expansion

The Dark Energy Camera, mounted on the Blanco Telescope in Chile, picked up images of the bright spot in the sky from the neutron star collision. UChicago, Argonne and Fermilab scientists are members of the international Dark Energy Survey collaboration.

Twenty years ago, scientists were shocked to realize that our universe is not only expanding, but that it's expanding faster over time.

Pinning down the exact rate of expansion, called the Hubble constant after famed astronomer and UChicago alumnus Edwin Hubble, has been surprisingly difficult. Since then scientists have used two methods to calculate the value, and they spit out distressingly different results. But last year's surprising capture of gravitational waves radiating from a neutron star collision offered a third way to calculate the Hubble constant.

That was only a single data point from one collision, but in a new paper published Oct. 17 in Nature, three University of Chicago scientists estimate that given how quickly researchers saw the first neutron star collision, they could have a very accurate measurement of the Hubble constant within five to ten years.

"The Hubble constant tells you the size and the age of the universe; it's been a holy grail since the birth of cosmology. Calculating this with gravitational waves could give us an entirely new perspective on the universe," said study author Daniel Holz, a UChicago professor in physics who co-authored the first such calculation from the 2017 discovery. "The question is: When does it become game-changing for cosmology?"

In 1929, Edwin Hubble announced that based on his observations of galaxies beyond the Milky Way, they seemed to be moving away from us -- and the farther away the galaxy, the faster it was receding. This is a cornerstone of the Big Bang theory, and it kicked off a nearly century-long search for the exact rate at which this is occurring.

To calculate the rate at which the universe is expanding, scientists need two numbers. One is the distance to a faraway object; the other is how fast the object is moving away from us because of the expansion of the universe. If you can see it with a telescope, the second quantity is relatively easy to determine, because the light you see when you look at a distant star gets shifted into the red as it recedes. Astronomers have been using that trick to see how fast an object is moving for more than a century -- it's like the Doppler effect, in which a siren changes pitch as an ambulance passes.

'Major questions in calculations'

But getting an exact measure of the distance is much harder. Traditionally, astrophysicists have used a technique called the cosmic distance ladder, in which the brightness of certain variable stars and supernovae can be used to build a series of comparisons that reach out to the object in question. "The problem is, if you scratch beneath the surface, there are a lot of steps with a lot of assumptions along the way," Holz said.

Perhaps the supernovae used as markers aren't as consistent as thought. Maybe we're mistaking some kinds of supernovae for others, or there's some unknown error in our measurement of distances to nearby stars. "There's a lot of complicated astrophysics there that could throw off readings in a number of ways," he said.

The other major way to calculate the Hubble constant is to look at the cosmic microwave background -- the pulse of light created at the very beginning of the universe, which is still faintly detectable. While also useful, this method also relies on assumptions about how the universe works.

The surprising thing is that even though scientists doing each calculation are confident about their results, they don't match. One says the universe is expanding almost 10 percent faster than the other. "This is a major question in cosmology right now," said the study's first author, Hsin-Yu Chen, then a graduate student at UChicago and now a fellow with Harvard University's Black Hole Initiative.

Then the LIGO detectors picked up their first ripple in the fabric of space-time from the collision of two stars last year. This not only shook the observatory, but the field of astronomy itself: Being able to both feel the gravitational wave and see the light of the collision's aftermath with a telescope gave scientists a powerful new tool. "It was kind of an embarrassment of riches," Holz said.

Gravitational waves offer a completely different way to calculate the Hubble constant. When two massive stars crash into each other, they send out ripples in the fabric of space-time that can be detected on Earth. By measuring that signal, scientists can get a signature of the mass and energy of the colliding stars. When they compare this reading with the strength of the gravitational waves, they can infer how far away it is.

This measurement is cleaner and holds fewer assumptions about the universe, which should make it more precise, Holz said. Along with Scott Hughes at MIT, he suggested the idea of making this measurement with gravitational waves paired with telescope readings in 2005. The only question is how often scientists could catch these events, and how good the data from them would be.

'It's only going to get more interesting'

The paper predicts that once scientists have detected 25 readings from neutron star collisions, they'll measure the expansion of the universe within an accuracy of 3 percent. With 200 readings, that number narrows to 1 percent.

"It was quite a surprise for me when we got into the simulations," Chen said. "It was clear we could reach precision, and we could reach it fast."

A precise new number for the Hubble constant would be fascinating no matter the answer, the scientists said. For example, one possible reason for the mismatch in the other two methods is that the nature of gravity itself might have changed over time. The reading also might shed light on dark energy, a mysterious force responsible for the expansion of the universe.

"With the collision we saw last year, we got lucky -- it was close to us, so it was relatively easy to find and analyze," said Maya Fishbach, a UChicago graduate student and the other author on the paper. "Future detections will be much farther away, but once we get the next generation of telescopes, we should be able to find counterparts for these distant detections as well."

The LIGO detectors are planned to begin a new observing run in February 2019, joined by their Italian counterparts at VIRGO. Thanks to an upgrade, the detectors' sensitivities will be much higher -- expanding the number and distance of astronomical events they can pick up.

Read more at Science Daily

Oldest weapons ever discovered in North America pre-date Clovis

A 15,000 year old stemmed point.

Texas A&M University researchers have discovered what are believed to be the oldest weapons ever found in North America: ancient spear points that are 15,500 years old. The findings raise new questions about the settlement of early peoples on the continent.

Michael Waters, distinguished professor of anthropology and director of the Center for the Study of the First Americans at Texas A&M, and colleagues from Baylor University and the University of Texas have had their work published in the current issue of Science Advances.

The team found the numerous weapons -- about 3-4 inches long -- while digging at what has been termed the Debra L. Friedkin site, named for the family who owns the land about 40 miles northwest of Austin in Central Texas. The site has undergone extensive archaeological work for the past 12 years.

Spear points made of chert and other tools were discovered under several feet of sediment that dating revealed to be 15,500 years old, and pre-date Clovis, who for decades were believed to be the first people to enter the Americas.

"There is no doubt these weapons were used for hunting game in the area at that time," Waters said. "The discovery is significant because almost all pre-Clovis sites have stone tools, but spear points have yet to be found. These points were found under a layer with Clovis and Folsom projectile points. Clovis is dated to 13,000 to 12,700 years ago and Folsom after that. The dream has always been to find diagnostic artifacts -- such as projectile points -- that can be recognized as older than Clovis and this is what we have at the Friedkin site."

Clovis is the name given to the distinctive tools made by people starting around 13,000 years ago. The Clovis people invented the "Clovis point," a spear-shaped weapon made of stone that is found in Texas and parts of the United States and northern Mexico and the weapons were made to hunt animals, including mammoths and mastodons, from 13,000 to 12,700 years ago.

"The findings expand our understanding of the earliest people to explore and settle North America," Waters said. "The peopling of the Americas during the end of the last Ice Age was a complex process and this complexity is seen in their genetic record. Now we are starting to see this complexity mirrored in the archaeological record."

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New Caledonian crows can create compound tools

This is a new Caledonian crow with a stick tool.

An international team of scientists from the Max Planck Institute for Ornithology in Seewiesen, Germany, and the University of Oxford have revealed that New Caledonian crows are able to create tools by combining two or more otherwise non-functional elements, an ability so far observed only in humans and great apes.

The new study shows that these birds can create long-reaching tools out of short combinable parts -- an astonishing mental feat. Assemblage of different components into novel functional and manoeuvrable tools has, until now, only been observed in apes, and anthropologists regard early human compound tool manufacture as a significant step in brain evolution. Children take several years before creating novel tools, probably because it requires anticipating properties of yet unseen objects. Such anticipation, or planning, is usually interpreted as involving creative mental modelling and executive functions.

The study demonstrates that this species of crow possess highly flexible abilities that allow them to solve complex problems involving anticipation of the properties of objects they have never seen. 'The finding is remarkable because the crows received no assistance or training in making these combinations, they figured it out by themselves,' says Auguste von Bayern, first author of the study from the Max-Planck-Institute for Ornithology and University of Oxford.

Famous for the use of tools

The New Caledonia crows (Corvus moneduloides) from the South Pacific are of the same species as Betty, who became famous in 2002 as the first animal shown to be able to create a hooked tool by bending a pliable material. Researchers had already been able to show how this remarkable species were able to use and make tools in the wild and in captivity, but they had never previously been seen to combine more than one piece to make a tool.

Alex Kacelnik from the University of Oxford says: 'The results corroborate that these crows possess highly flexible abilities that allow them to solve novel problems rapidly, but do not show how they do it. It is possible that they use some form of virtual simulation of the problem, as if different potential actions were played in their brains until they figure out a viable solution, and then do it. Similar processes are being modelled on artificial intelligences and implemented in physical robots, as a way to better understand the animals and to discover ways to build machines able to reach autonomous creative solutions to novel problems.'

The researchers presented eight New Caledonian crows with a puzzle box they had never encountered before, containing a small food container behind a door that left a narrow gap along the bottom. Initially, the scientists left some sufficiently long sticks scattered around, and all the birds rapidly picked one of them, inserted it through the front gap, and pushed the food to an opening on the side of the box. All eight birds did this without any difficulty. In the next steps, the scientists left the food deep inside the box but provided only short pieces, too short to reach the food. These short pieces could potentially be combined with each other, as some were hollow and others could fit inside them.

Without any help or demonstration, four of the crows partially inserted one piece into another and used the resulting longer compound pole to reach and extract the food. At the end of the five-step investigation, the scientists made the task more difficult by supplying even shorter combinable parts, and found that one particular bird, 'Mango', was able to make compound tools out of three and even four parts.

Read more at Science Daily

Mystery of how black widow spiders create steel-strength silk webs further unravelled

Latrodectus hesperus, known commonly as the black widow spider in North America. Researchers at Northwestern University and San Diego State University have unraveled the complex process of how black widow spiders transform proteins into steel-strength fibers, potentially aiding scientists in creating equally strong synthetic materials.

Researchers at Northwestern University and San Diego State University (SDSU) have better unraveled the complex process of how black widow spiders transform proteins into steel-strength fibers. This knowledge promises to aid scientists in creating equally strong synthetic materials.

Black widow spiders and their relatives, native to temperate climates in North America, Europe, Asia, Australia, Africa and South America, produce an array of silks with exceptional materials properties.

Scientists have long known the primary sequence of amino acids that make up some spider silk proteins and understood the structure of the fibers and webs. Previous research theorized that spider silk proteins await the spinning process as nano-size amphiphilic spherical micelles (clusters of water soluble and non-soluble molecules) before being funneled through the spider's spinning apparatus to form silk fibers. However, when scientists attempted to replicate this process, they were unable to create synthetic materials with the strengths and properties of native spider silk fibers.

"The knowledge gap was literally in the middle," Northwestern's Nathan C. Gianneschi said. "What we didn't understand completely is what goes on at the nanoscale in the silk glands or the spinning duct -- the storage, transformation and transportation process involved in proteins becoming fibers."

Gianneschi is the Jacob and Rosaline Cohn Professor in the department of chemistry in the Weinberg College of Arts and Sciences and in the departments of materials science and engineering and of biomedical engineering in the McCormick School of Engineering. He and Gregory P. Holland, associate professor in the department of chemistry and biochemistry at SDSU and the author of more than 40 papers on spider silk, are the paper's co-corresponding authors.

The research will be published online the week of Oct. 22 in the Proceedings of the National Academy of Sciences (PNAS).

Utilizing complementary, state-of-the-art techniques -- nuclear magnetic resonance (NMR) spectroscopy, the same technology utilized in MRI, at SDSU, followed by electron microscopy at Northwestern -- the research team was able to more closely see inside the protein gland where the silk fibers originate, revealing a much more complex, hierarchical protein assembly.

This "modified micelles theory" concludes that spider silk proteins do not start out as simple spherical micelles, as previously thought, but instead as complex, compound micelles. This unique structure is potentially required to create the black widow spider's impressive fibers.

"We now know that black widow spider silks are spun from hierarchical nano-assemblies (200 to 500 nanometers in diameter) of proteins stored in the spider's abdomen, rather than from a random solution of individual proteins or from simple spherical particles," Holland said.

If duplicated, "the practical applications for a material like this are essentially limitless," Holland said, and could include high-performance textiles for military, first responders and athletes; building materials for cable bridges and other construction; environmentally friendly replacements for plastics; and biomedical applications.

Read more at Science Daily

New human cell structure discovered

Cell division.

A new structure in human cells has been discovered by researchers at Karolinska Institutet in Sweden in collaboration with colleagues in the UK. The structure is a new type of protein complex that the cell uses to attach to its surroundings and proves to play a key part in cell division. The study is published in the journal Nature Cell Biology.

The cells in a tissue are surrounded by a net-like structure called the extracellular matrix. To attach itself to the matrix the cells have receptor molecules on their surfaces, which control the assembly of large protein complexes inside them.

These so-called adhesion complexes connect the outside to the cell interior and also signal to the cell about its immediate environment, which affects its properties and behaviour.

Researchers at Karolinska Institutet have now discovered a new type of adhesion complex with a unique molecular composition that sets it apart from those already known about. The discovery has been made in collaboration with researchers in the UK.

"It's incredibly surprising that there's a new cell structure left to discover in 2018," says principal investigator Staffan Strömblad, professor at the Department of Biosciences and Nutrition, Karolinska Institutet. "The existence of this type of adhesion complex has completely passed us by."

The newly discovered adhesion complex can provide answers to an as-yet unanswered question -- how the cell can remain attached to the matrix during cell division. The previously known adhesion complexes dissolve during the process to allow the cell to divide. But not this new type.

"We've shown that this new adhesion complex remains and attaches the cell during cell division," says Professor Strömblad.

The researchers also show that the newly discovered structures control the ability of daughter cells to occupy the right place after cell division. This memory function was interrupted when the researchers blocked the adhesion complex.

The study was done on human cell lines mainly using confocal microscopy and mass spectrometry. Further research is now needed to examine the new adhesion complex in living organisms.

"Our findings raise many new and important questions about the presence and function of these structures," says Professor Strömblad. "We believe that they're also involved in other processes than cell division, but this remains to be discovered."

Read more at Science Daily

Gravitational waves could shed light on dark matter

Snapshots of the 120 million particle simulation of two merging dwarf galaxies, which each contain a blackhole, between 6 and 7.5 billion years

The Laser Interferometer Space Antenna (LISA) will enable astrophysicists to observe gravitational waves emitted by black holes as they collide with or capture other black holes. LISA will consist of three spacecraft orbiting the sun in a constant triangle formation. Gravitational waves passing through will distort the sides of the triangle slightly, and these minimal distortions can be detected by laser beams connecting the spacecraft. LISA could therefore add a new sense to scientists' perception of the universe and enable them to study phenomena invisible in different light spectra.

Dwarf galaxies are natural laboratories

Scientists from the Center for Theoretical Astrophysics and Cosmology of the University of Zurich, together with colleagues from Greece and Canada, have now found that LISA will not only be able to measure these previously unstudied waves, but could also help to unveil secrets about another mysterious part of the universe: dark matter.

Dark matter particles are thought to account for approx. 85% of the matter in the universe. However, they are still only hypothetical -- the name refers to their "hiding" from all previous attempts to see, let alone study them. But calculations show that many galaxies would be torn apart instead of rotating if they weren't held together by a large amount of dark matter.

That is especially true for dwarf galaxies. While such galaxies are small and faint, they are also the most abundant in the universe. What makes them particularly interesting for astrophysicists is that their structures are dominated by dark matter, making them "natural laboratories" for studying this elusive form of matter.

Black holes and dark matter are connected

As reported in Astrophysical Journal Letters, high-resolution computer simulations of the birth of dwarf galaxies, designed and carried out by UZH PhD student Tomas Ramfal, yielded surprising results. Calculating the interplay of dark matter, stars and the central black holes of these galaxies, the team of scientists from Zurich discovered a strong link between the merger rates of these black holes and the amount of dark matter at the center of dwarf galaxies. Measuring gravitational waves emitted by merging black holes can thus provide hints about the properties of the hypothetical dark matter particle.

The newly found connection between black holes and dark matter can now be described in a mathematical and exact way for the first time. But it is far from being a chance finding, stresses Lucio Mayer, the group leader: "Dark matter is the distinguishing quality of dwarf galaxies. We had therefore long suspected that this should also have a clear effect on cosmological properties."

Read more at Science Daily

When fathers exercise, children are healthier, even as adults

Matt Hurt shows his five-year-old son how to swing a baseball bat. A new study suggests that fathers can give their children a genetic head start on a healthy metabolism by exercising prior to conception.

Men who want to have children in the near future should consider hitting the gym.

In a new study led by Kristin Stanford, a physiology and cell biology researcher with The Ohio State University College of Medicine at the Wexner Medical Center, paternal exercise had a significant impact on the metabolic health of offspring well into their adulthood.

Laurie Goodyear of the Joslin Diabetes Center and Harvard Medical School co-led the study, published today in the journal Diabetes.

"This work is an important step in learning about metabolic disease and prevention at the cellular level," said Dr. K. Craig Kent, dean of the Ohio State College of Medicine.

Recent studies have linked development of type 2 diabetes and impaired metabolic health to the parents' poor diet, and there is increasing evidence that fathers play an important role in obesity and metabolic programming of their offspring.

Stanford is a member of Ohio State's Diabetes and Metabolism Research Center. Her team investigated how a father's exercise regimen would affect his offspring's metabolic health. Using a mouse model, they fed male mice either a normal diet or a high-fat diet for three weeks. Some mice from each diet group were sedentary and some exercised freely. After three weeks, the mice bred and their offspring ate a normal diet under sedentary conditions for a year.

The researchers report that adult offspring from sires who exercised had improved glucose metabolism, decreased body weight and a decreased fat mass.

"Here's what's really interesting; offspring from the dads fed a high-fat diet fared worse, so they were more glucose intolerant. But exercise negated that effect," Stanford said. "When the dad exercised, even on a high-fat diet, we saw improved metabolic health in their adult offspring."

Stanford's team also found that exercise caused changes in the genetic expression of the father's sperm that suppress poor dietary effects and transfer to the offspring.

"We saw a strong change in their small-RNA profile. Now we want to see exactly which small-RNAs are responsible for these metabolic improvements, where it's happening in the offspring and why," Stanford said.

Previous studies from this group have shown that when mouse mothers exercise, their offspring also have beneficial effects of metabolism.

"Based on both studies, we're now determining if both parents exercising has even greater effects to improve metabolism and overall health of offspring. If translated to humans, this would be hugely important for the health of the next generation," Goodyear said.

The researchers believe the results support the hypothesis that small RNAs could help transmit parental environmental information to the next generation.

"There's potential for this to translate to humans. We know that in adult men obesity impairs testosterone levels, sperm number and motility, and it decreases the number of live births," Stanford said. "If we ask someone who's getting ready to have a child to exercise moderately, even for a month before conception, that could have a strong effect on the health of their sperm and the long-term metabolic health of their children."

Read more at Science Daily

Rising temperatures and human activity are increasing storm runoff and flash floods

A new study sheds light on the rising magnitude of extreme flash floods.

Hurricanes Florence and Michael in the U.S. and Super Typhoon Mangkhut in the Philippines have shown the widespread and harmful impact of weather extremes on both ecosystems and built communities, with flash floods causing more deaths, as well as property and agriculture losses than from any other severe weather-related hazards. These losses have been increasing over the past 50 years and have exceeded $30 billion per year in the past decade. Globally, almost one billion people now live in floodplains, raising their exposure to river flooding from extreme weather events and underscoring the urgency in understanding and predicting these events.

Columbia Engineering researchers have demonstrated for the first time that runoff extremes have been dramatically increasing in response to climate and human-induced changes. Their findings, published today in Nature Communications, show a large increase in both precipitation and runoff extremes driven by both human activity and climate change. The team, led by Pierre Gentine, associate professor of earth and environmental engineering and affiliated with the Earth Institute, also found that storm runoff has a stronger response than precipitation to human-induced changes (climate change, land-use land-cover changes, etc). This suggests that projected responses of storm runoff extremes to climate and anthropogenic changes are going to increase dramatically, posing large threats to the ecosystem, affecting community resilience and infrastructure systems.

The researchers discovered that changes in storm runoff extremes in most regions of the world are in line with or higher than those of precipitation extremes. They noted that different responses of precipitation and storm runoff to temperature can be attributed not only to warming, but also to factors like land-use and land-cover changes, water and land management, and vegetation changes that have altered the underlying surface conditions and hydrological feedbacks that have, in turn, increased storm runoff.

"Our work helps explain the underlying physical mechanisms related to the intensification of precipitation and runoff extremes," Gentine said. "This will help improve flood forecasting and early-warning alerts. Our findings can help provide scientific guidance for infrastructure and ecosystem resilience planning, and could help formulate strategies for tackling climate change."

Precipitation is generated after water vapour condenses in the atmosphere, and precipitation intensity is governed by the availability of atmospheric water vapour. Because the atmosphere can hold more moisture as temperature rises, climate scientists expect to see an intensification of precipitation extremes with climate change.

Because previous studies mainly investigated the precipitation response, Gentine's team decided to examine the response of both precipitation and storm runoff extremes to naturally and anthropogenically driven changes in surface temperature and atmospheric moisture content. They performed a global scale hydrological analysis to characterize the responses and their underlying physical mechanisms. The researchers then assessed the influence of variability across decades on the scaling of runoff extremes and temperature, then systematically compared this with changes in precipitation extremes. Their observational daily runoff data came from the Global Runoff Data Centre (GRDC) datasets, and daily precipitation and near-surface air temperature data from Global Summary of the Day (GSOD) dataset.

"We were trying to find the physical mechanisms behind why precipitation and runoff extremes are increasing all over the globe," said the study's lead author Jiabo Yin, a visiting student from Wuhan University working in Gentine's group. "We know that precipitation and runoff extremes will significantly intensify in the future, and we need to modify our infrastructures accordingly. Our study establishes a framework for investigating the runoff response."

Read more at Science Daily

New fly species found in Indiana may indicate changing climate

These are various Lucilia blow flies collected.

A new type of blow fly spotted in Indiana points to shifting species populations due to climate change. Researchers at IUPUI have observed the first evidence of Lucilia cuprina in Indiana, an insect previously known to populate southern states from Virginia to California.

Researchers recorded the L. cuprina species more than two dozen times from 2015 to 2017 in parks and other public places throughout Central Indiana. The fly was observed as far north as Michigan in the 1950s during a short period of warmer temperatures but had not been found in this region since then.

"As temperatures change and increase, the distributions of these insects will continue to change as well," said Christine J. Picard, an associate professor of biology. "There is definitely a northward movement of species -- not just insects, but all species -- as they try to find temperatures where they are more comfortable."

The movement of this species of fly into the Midwest could also have implications for forensic investigations involving decomposing remains. The growth and development of flies play an important role for scientists looking to learn how long a human or animal has been dead.

"With forensic science and forensic entomology, you should have an idea of which flies are present in your location in part because different species will have different development times," Picard said.

The L. cuprina blow fly's sister species Lucilla sericata is widely present in Indiana and is often used in forensic cases. Since the two species are so closely related, it's difficult to tell them apart. If investigators don't know they are dealing with an L. cuprina instead of the more typically seen L. sericata, their data could be inaccurate.

From Science Daily

Clues to how birds began to fly

Daubenton's bat flying.

For the first time, researchers have measured what is known as the ground effect of flying animals -- and it turns out that they save a lot more energy by flying close to the ground than previously believed. The study from Lund University in Sweden supports one of the theories on how birds began to fly.

"Our measurements show that the ground effect saves animals twice as much energy as models have suggested.," says Christoffer Johansson, biologist at Lund University.

For the first time, Christoffer Johansson, together with colleagues Anders Hedenström at Lund University and Lasse Jakobsen at the University of Southern Denmark, have successfully managed to measure the ground effect when Daubenton's bats fly in a wind tunnel.

In short, the ground effect means that a surface, ground or water, acts as an aerodynamic mirror that increases the air pressure under the wings -- it costs less to generate lift. The ground effect is achieved within one wingspan of the surface, and the effect decreases exponentially with distance to the surface. An even surface, e.g. a calm lake where bats and birds catch insects or drink while they fly, provides optimal conditions. The new study also shows that animals use even less energy if they flap their wings rather than gliding near the ground.

Although the study was performed on bats, it has implications for birds and insects. One theory of how animals developed the art of flying is that they threw themselves between branches and trees. Another theory is that flying began on the ground. By running and jumping, proto-wings could have allowed the animals to run faster and jump higher and eventually flight evolved, a theory commonly known as the "ground up" theory. The corresponding theory behind today's flying insects is that they moved on the water surface and eventually evolved wings as a means of propelling themselves across the surface.

"This is obviously speculation, but if flapping animals save more energy than we previously believed by flying close to the ground, then the ground up theory becomes more probable, i.e. that the animals began to fly by first running and jumping on the ground with flapping precursors to wings.," says Christoffer Johansson.

Video: Daubenton's bat flying in ground effect -- https://www.youtube.com/watch?v=U_qCoNGy454

From Science Daily