May 24, 2018

People with family history of alcoholism release more dopamine in expectation of alcohol

People with a family history of alcohol use disorder (AUD) release more dopamine in the brain's main reward center in response to the expectation of alcohol than people diagnosed with the disorder, or healthy people without any family history of AUD, reports a new study in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

"This exaggerated reward center stimulation by expectation of alcohol may put the [individuals with family history] at greater risk of alcohol use disorder, and could be a risk factor in itself," said first author Lawrence Kegeles, MD, PhD, of Columbia University.

The study examined a range of risk for AUD, including 34 healthy participants with no family history of AUD, 16 healthy participants with a family history of the disorder (referred to as the family-history positive, or FHP, group), and 15 participants diagnosed with AUD. Dr. Kegeles and colleagues used PET brain scanning to measure the amount of dopamine release in areas of the brain important for reward and addiction. The participants underwent the brain scans after receiving either an alcohol drink -- a cocktail of vodka, tonic, and cranberry -- or a placebo drink without the vodka. Although the participants didn't know the order in which they would receive the drinks, if they received the placebo drink first they were cued into expecting the alcohol drink next.

All three groups had similar dopamine release-levels in response to the alcohol, suggesting that alcohol-induced dopamine release is normal in AUD. However, "we found that the FHP participants had a much more pronounced response to the placebo drink than the other groups, indicating that expectation of alcohol caused the FHP group to release more reward center dopamine," said Dr. Kegeles. The release of dopamine into the reward center is thought to reinforce alcohol consumption and possibly contribute to risk of AUD.

"This research finding exemplifies how advances in imaging brain chemistry using PET scanning can provide new insights into how differences in brain function in people with a family history of alcoholism can explain their own potential for addiction," said Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

Read more at Science Daily

When the dinosaurs died, so did forests -- and tree-dwelling birds

The asteroid impact that eliminated non-avian dinosaurs destroyed global forests. Here, a hyopothetical surviving bird lineage -- small-bodied and specialized for a ground-dwelling lifestyle--flees a burning forest in the aftermath of the asteroid strike.
Sixty-six million years ago, the world burned. An asteroid crashed to Earth with a force one million times larger than the largest atomic bomb, causing the extinction of the dinosaurs. But dinosaurs weren't the only ones that got hit hard -- in a new study, scientists learned that the planet's forests were decimated, leading to the extinction of tree-dwelling birds.

"Looking at the fossil record, at plants and birds, there are multiple lines of evidence suggesting that the forest canopies collapsed," says Regan Dunn, a paleontologist at the Field Museum in Chicago and a co-author on the study in Current Biology. "Perching birds went extinct because there were no more perches."

"We drew on a variety of approaches to stitch this story together," said Daniel Field, the paper's lead author, of the Milner Centre for Evolution at the University of Bath. "We concluded that the temporary elimination of forests in the aftermath of the asteroid impact explains why arboreal birds failed to survive across this extinction event. The ancestors of modern arboreal birds did not move into the trees until forests had recovered from the extinction-causing asteroid."

The project's pollen expert, Antoine Bercovici of the Smithsonian Institution and the Denver Museum of Nature and Science, helped determine that the world's forests were destroyed by looking at microscopic fossils of pollen and spores. Dunn explains, "After a disaster like a forest fire or a volcanic eruption, the first plants to come back are the fastest colonizers -- especially ferns." That's because ferns don't sprout from seeds, but from spores, which are much smaller -- just a single cell. "Spores are minuscule, the size of a grain of pollen, so they're easily dispersed. They get picked up by the wind and go further than seeds can, and all they need to grow is a wet spot."

"The spores are tiny -- you could fit four across a single strand of your hair," says Dunn. "To see them, we take a sample of rock from the time frame just after the collision and dissolve it in acid. Then we purify it so that all that remains is the organic debris, like pollen, spores and little leaf bits, then we look at them under a microscope."

Immediately after the asteroid hit, the fossil record shows the charcoal remains of burnt trees, and then, tons of fern spores. An abundance of fern spores in the fossil record often comes on the heels of a natural disaster that destroyed larger plants like trees.

"Our study examined the fossil record from New Zealand, Japan, Europe and North America, which showed there was a mass deforestation across the globe at the end of the Cretaceous period," says co-author Bercovici.

And with no more trees, the scientists found, tree-dwelling birds went extinct. The birds that did survive were ground-dwellers -- birds whose fossilized remains show longer, sturdier legs like we see in modern ground birds like kiwis and emus. The Cretaceous equivalent of robins and sparrows, with delicate little legs made for perching on tree branches, had no place to live.

"Today, birds are the most diverse and globally widespread group of terrestrial vertebrate animals -- there are nearly 11,000 living species," says Field. "Only a handful of ancestral bird lineages succeeded in surviving the mass extinction event 66 million years ago, and all of today's amazing living bird diversity can be traced to these ancient survivors."

And while fossil animals like dinosaurs and birds often get more love than fossil plants, Dunn says that plants are critical to understanding life on earth. "Plants are everything, plants are the context in which all terrestrial life evolves and survives. They're primary producers, they make energy available to all life forms by capturing it from the sun -- we can't do that."

Read more at Science Daily

Unprecedented detail in pulsar 6,500 light-years from Earth

The pulsar PSR B1957+20 is seen in the background through the cloud of gas enveloping its brown dwarf star companion.
A team of astronomers has performed one of the highest resolution observations in astronomical history by observing two intense regions of radiation, 20 kilometres apart, around a star 6500 light-years away.

The observation is equivalent to using a telescope on Earth to see a flea on the surface of Pluto.

The extraordinary observation was made possible by the rare geometry and characteristics of a pair of stars orbiting each other. One is a cool, lightweight star called a brown dwarf, which features a "wake" or comet-like tail of gas. The other is an exotic, rapidly spinning star called a pulsar.

"The gas is acting as like a magnifying glass right in front of the pulsar," says Robert Main, lead author of the paper describing the observation being published May 24 in the journal Nature. "We are essentially looking at the pulsar through a naturally occurring magnifier which periodically allows us to see the two regions separately."

Main is a PhD astronomy student in the Department of Astronomy & Astrophysics at the University of Toronto, working with colleagues at the University of Toronto's Dunlap Institute for Astronomy & Astrophysics and Canadian Institute for Theoretical Astrophysics, and the Perimeter Institute.

The pulsar is a neutron star that rotates rapidly -- over 600 times a second. As the pulsar spins, it emits beams of radiation from the two hotspots on its surface. The intense regions of radiation being observed are associated with the beams.

The brown dwarf star is about a third the diameter of the Sun. It is roughly two million kilometres from the pulsar -- or five times the distance between the Earth and the moon -- and orbits around it in just over 9 hours. The dwarf companion star is tidally locked to the pulsar so that one side always faces its pulsating companion, the way the moon is tidally locked to the Earth.

Because it is so close to the pulsar, the brown dwarf star is blasted by the strong radiation coming from its smaller companion. The intense radiation from the pulsar heats one side of the relatively cool dwarf star to the temperature of our Sun, or some 6000°C.

The blast from the pulsar could ultimately spell its companion's demise. Pulsars in these types of binary systems are called "black widow" pulsars. Just as a black widow spider eats its mate, it is thought that the pulsar, given the right conditions, could gradually erode gas from the dwarf star until the latter is consumed.

In addition to being an observation of incredibly high resolution, the result could be a clue to the nature of mysterious phenomena known as Fast Radio Bursts, or FRBs.

Read more at Science Daily

Utah fossil reveals global exodus of mammals' near relatives to major continents

The new species Cifelliodon wahkarmoosuch is estimated to have weighed 2.5 pounds and probably grew to be about the size of a small hare.
A nearly 130-million-year-old fossilized skull found in Utah is an Earth-shattering discovery in one respect.

The small fossil is evidence that the super-continental split likely occurred more recently than scientists previously thought and that a group of reptile-like mammals that bridge the reptile and mammal transition experienced an unsuspected burst of evolution across several continents.

"Based on the unlikely discovery of this near-complete fossil cranium, we now recognize a new, cosmopolitan group of early mammal relatives," said Adam Huttenlocker, lead author of the study and assistant professor of clinical integrative anatomical sciences at the Keck School of Medicine of USC.

The study, published in the journal Nature on May 16, updates the understanding of how mammals evolved and dispersed across major continents during the age of dinosaurs. It suggests that the divide of the ancient landmass Pangea continued for about 15 million years later than previously thought and that mammal migration and that of their close relatives continued during the Early Cretaceous (145 to 101 million years ago).

"For a long time, we thought early mammals from the Cretaceous (145 to 66 million years ago) were anatomically similar and not ecologically diverse," Huttenlocker said. "This finding by our team and others reinforce that, even before the rise of modern mammals, ancient relatives of mammals were exploring specialty niches: insectivores, herbivores, carnivores, swimmers, gliders. Basically, they were occupying a variety of niches that we see them occupy today."

The study reveals that the early mammal precursors migrated from Asia to Europe, into North America and further onto major Southern continents, said Zhe-Xi Luo, senior author of the study and a paleontologist at the University of Chicago.

Fossil find: a new species

Huttenlocker and his collaborators at the Utah Geological Survey and The University of Chicago named the new species Cifelliodon wahkarmoosuch.

Found in the Cretaceous beds in eastern Utah, the fossil is named in honor of famed paleontologist Richard Cifelli. The species name, "wahkarmoosuch" means "yellow cat" in the Ute tribe's language in respect of the area where it was found.

Scientists used high-resolution computed tomography (CT) scanners to analyze the skull.

"The skull of Cifelliodon is an extremely rare find in a vast fossil-bearing region of the Western Interior, where the more than 150 species of mammals and reptile-like mammal precursors are represented mostly by isolated teeth and jaws," said James Kirkland, study co-author in charge of the excavation and a Utah State paleontologist.

With an estimated body weight of up to 2.5 pounds, Cifelliodon would seem small compared to many living mammals, but it was a giant among its Cretaceous contemporaries. A full-grown Cifelliodon was probably about the size of a small hare or pika (small mammal with rounded ears, short limbs and a very small tail).

It had teeth similar to fruit-eating bats and could nip, shear and crush. It might have incorporated plants into its diet.

The newly named species had a relatively small brain and giant "olfactory bulbs" to process sense of smell. The skull had tiny eye sockets, so the animal probably did not have good eyesight or color vision. It possibly was nocturnal and depended on sense of smell to root out food, Huttenlocker said.

Supercontinent existed longer than previously thought

Huttenlocker and his colleagues placed Cifelliodon within a group called Haramiyida, an extinct branch of mammal ancestors related to true mammals. The fossil was the first of its particular subgroup -- Hahnodontidae -- found in North America.

The fossil discovery emphasizes that haramiyidans and some other vertebrate groups existed globally during the Jurassic-Cretaceous transition, meaning the corridors for migration via Pangean landmasses remained intact into the Early Cretaceous.

Most of the Jurassic and Cretaceous fossils of haramiyidans are from the Triassic and Jurassic of Europe, Greenland and Asia. Hahnodontidae was previously known only from the Cretaceous of Northern Africa. It is to this group that Huttenlocker argues Cifelliodon belongs, providing evidence of migration routes between the continents that are now separated in northern and southern hemispheres.

Read more at Science Daily

May 23, 2018

Lightening up dark galaxies

One of the new dark-galaxy candidates, identified through a combination of spectral information (left) and images reflecting the emission of gas (middle) and stars (right). The position of the dark-galaxy candidate is marked by the red circle.
Despite substantial progress over the past half a century in understanding of how galaxies form, important open questions remain regarding how precisely the diffuse gas known as the 'intergalactic medium' is converted into stars. One possibility, suggested in recent theoretical models, is that the early phase of galaxy formation involves an epoch when galaxies contain a great amount of gas but are still inefficient at forming stars. Direct proof of such a 'Dark Phase' has been so far elusive, however -- after all, dark galaxies do not emit much visible light. The observational discovery of such galaxies would therefore fill an important gap in our understanding of galaxy evolution.

There are ways to bring dark galaxies to lighten up though. An international team led by Dr. Raffaella Anna Marino and Prof. Sebastiano Cantalupo from the Department of Physics at ETH Zurich has now done just that and thus was able to search the sky for potential dark galaxies with unprecedented efficiency. And successfully so, as they report in a paper published today in The Astrophysical Journal: they have identified at least six strong candidates for dark galaxies.

To overcome the obstacle that their target objects are dark, the team used a flashlight of sorts, which came in the form of quasars. These emit intense ultraviolet light, which in turn induces fluorescent emission in hydrogen atoms known as the Lyman-alpha line. As a result, the signal from any dark galaxies in the vicinity of the quasar gets a boost, making them visible. Such 'fluorescent illumination' has been used before in searches for dark galaxies, but Marino et al. now looked at the neighbourhood of quasars at greater distances than has been possible in earlier observations.

Also, they acquired the full spectral information for each of the dark-galaxy candidates. Deep observations -- 10 hours for each of the six quasar fields they studied -- enabled Marino and her colleagues to efficiently tell dark-galaxy candidates apart from other sources. From initially 200 Lyman-alpha emitters, half a dozen regions remained that are unlikely to be normal star-forming stellar populations, making them robust candidates for dark galaxies.

The advances in observational capability have become possible thanks to the Multi Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT) of the European Southern Observatory (ESO) in Chile. In essence, previous studies were limited to imaging a relative narrow band of frequencies, for which specific filters had to be designed. The MUSE instrument instead allowed hunting 'blindly' -- without filters -- for dark galaxies around quasars at larger distances from Earth than had been possible so far.

From Science Daily

Birds from different species recognize each other and cooperate

This is a splendid fairy-wren.
Cooperation among different species of birds is common. Some birds build their nests near those of larger, more aggressive species to deter predators, and flocks of mixed species forage for food and defend territories together in alliances that can last for years. In most cases, though, these partnerships are not between specific individuals of the other species -- any bird from the other species will do.

But in a new study published in the journal Behavioral Ecology, scientists from the University of Chicago and University of Nebraska show how two different species of Australian fairy-wrens not only recognize individual birds from other species, but also form long-term partnerships that help them forage and defend their shared space as a group.

"Finding that these two species associate was not surprising, as mixed species flocks of birds are observed all over the world," said Allison Johnson, PhD, a postdoctoral scholar at the University of Nebraska who conducted the study as part of her dissertation research at UChicago. "But when we realized they were sharing territories with specific individuals and responding aggressively only to unknown individuals, we knew this was really unique. It completely changed our research and we knew we had to investigate it."

Variegated fairy-wrens and splendid fairy-wrens are two small songbirds that live in Australia. The males of each species have striking, bright blue feathers that make them popular with bird watchers. Their behavior also makes them an appealing subject for biologists. Both species feed on insects, live in large family groups, and breed during the same time of year. They are also non-migratory, meaning they live in one area for their entire lives, occupying the same eucalyptus scrublands that provide plenty of bushes and trees for cover.

When these territories overlap, the two species interact with each other. They forage together, travel together, and seem to be aware of what the other species is doing. They also help each other defend their territory from rivals. Variegated fairy-wrens will defend their shared territory from both variegated and splendid outsiders; splendid fairy-wrens will do the same, while fending off unfamiliar birds from both species.

"Splendid and variegated fairy-wrens are so similar in their habitat preferences and behavior, we would expect them to act as competitors. Instead, we've found stable, positive relationships between individuals of the two species," said Christina Masco, PhD, a graduate student at UChicago and a co-author on the new paper.

Many songbirds can recognize familiar members of their own species on the basis of the unique songs each bird sings. However, in this research the investigators believed this recognition occurred across species. How could they be so certain?

From 2012-2015, Johnson, Masco, and their former advisor, Stephen Pruett-Jones, PhD, associate professor of ecology and evolution at UChicago, studied these species at Brookfield Conservation Park in South Australia. The first unusual observation Johnson made was that when playing a recorded vocalization of one species, the other species would respond and fly in to investigate what was going on.

To follow up on this observation, the researchers monitored both fairy-wren species in the darkness before dawn and captured clear recordings of their signature songs. After sunrise, they broadcast the recorded songs from a speaker to simulate an intrusion by a particular bird into a group's territory. The objective was to see how territory owners reacted to the songs of familiar and unfamiliar members of the other species.

The researchers placed a speaker about 30 meters away from a subject fairy-wren and played the songs of four different individuals: a fairy-wren that occupied the same territory (a co-resident or "friendly" bird), a fairy-wren from an adjacent territory (a neighbor), a fairy-wren from an area five or more territories away (an unknown bird), and a red-capped robin, a common species in the park that doesn't pose a threat to the fairy-wrens (as a control group).

Both splendid and variegated fairy-wrens demonstrated the ability to recognize their co-residents' songs despite the species difference. Socially dominant males of both species responded more aggressively to songs of neighbors and unknown birds of the other fairy-wren species than they did to friendly birds sharing their territory, or to the red-capped robin. When they heard songs from friendly birds, they didn't respond, suggesting they didn't see them as a threat.

By forming and keeping these associations with another species, fairy-wrens can better defend their nests from predators and their territories from rivals. There is also evidence that interacting with the other species has additional benefits besides territorial defense. While the splendid fairy-wrens didn't change their behavior when associating with the other species, the variegated fairy-wrens spent more time foraging, were less vigilant, and had more success raising their young.

Johnson, Masco, and Pruett-Jones believe the fairy-wrens associate with the other species as a form of cooperation. By interacting with other species that share the same territory instead of working against them, these already social species create a larger group to help defend their territory and ward off intruders. In other words, if you can't beat 'em, join 'em.

Read more at Science Daily

Study casts doubt on traditional view of pterosaur flight

This is an image of a reliable reconstruction. Soft tissues like ligaments play a big role in determining a joint's range of motion. But soft tissues rarely fossilize, causing problems for paleontologists trying to reconstruct who extinct creatures may have lived. Now researchers have shown a new method for inferring the extent to which ligaments inhibit joint movement, which could be helpful in reconstructing ancient species.
Most renderings and reconstructions of pterodactyls and other extinct flying reptiles show a flight pose much like that of bats, which fly with their hind limbs splayed wide apart. But a new method for inferring how ancient animals might have moved their joints suggests that pterosaurs probably couldn't strike that pose.

"Most of the work that's being done right now to understand pterosaur flight relies on the assumption that their hips could get into a bat-like pose," said Armita Manafzadeh, a Ph.D. student at Brown University who led the research with Kevin Padian of the University of California, Berkeley. "We think future studies should take into account that this pose was likely impossible, which might change our perspective when we consider the evolution of flight in pterosaurs and dinosaurs."

The research, published in Proceedings of the Royal Society B, is an effort to help paleontologists infer the range of motion of joints in a way that takes into account the soft tissues -- particularly ligaments -- that play key roles in how joints work. Generally, soft tissues don't fossilize, leaving paleontologists to infer joint motion from bones alone. And there aren't many constraints on how that's done, Manafzadeh says. So she wanted to find a way to use present-day animals to test the extent to which ligaments limit joint motion.

It's an idea that started with grocery store chickens, Manafzadeh says.

"If you pick up a raw chicken at the grocery store and move its joints, you'll reach a point where you'll hear a pop," she said. "That's the ligaments snapping. But if I handed you a chicken skeleton without the ligaments, you might think that its joints could do all kinds of crazy things. So the question is, if you were to dig up a fossil chicken, how would you think its joints could move, and how wrong would you be?"

For this latest study, she used not a grocery store chicken, but dead quail. Birds are the closest living relative of extinct pterosaurs and four-winged dinosaurs. After carefully cutting away the muscles surrounding the birds' hip joints, she manipulated the joints while taking x-ray videos. That way, she could determine the exact 3-D positions of the bones in poses where the ligaments prevented further movement.

This technique enabled Manafzadeh to map out the range of motion of the quail hip with ligaments attached, which she could then compare to the range of motion that might have been inferred from bones alone. For the bones-only poses, Manafzadeh used traditional criteria that paleontologists often use -- stopping where the two bones hit each other and when the movement pulled the thigh bone out of its socket.

She found that over 95 percent of the joint positions that seemed plausible with bones alone were actually impossible when ligaments were attached.

The next step was to work out how the range of motion of present-day quail hips might compare to the range of motion for extinct pterosaurs and four-winged dinosaurs.

The assumption has long been that these creatures flew a lot like bats do. That's partly because the wings of pterosaurs were made of skin and supported by an elongated fourth finger, which is somewhat similar to the wings of bats. Bat wings are also connected to their hind limbs, which they splay out widely during flight. Many paleontologists, Manafzadeh says, assume pterosaurs and four-winged dinosaurs did the same. But her study suggests that wasn't possible.

In quail, a bat-like hip pose seemed possible based on bones alone, but outward motion of the thigh bone was inhibited by one particular ligament -- a ligament that's present in a wide variety of birds and other reptiles related to pterosaurs. No evidence, Manafzadeh says, suggests that extinct dinosaurs and pterosaurs wouldn't have had this ligament, too.

And with that ligament attached, this new study suggests that the bat-like pose would be impossible. According to Manafzadeh's work, this pose would require the ligament to stretch 63 percent more than the quail ligament can. That's quite a stretch, she says.

"That's a huge difference that would need to be accounted for before it can be argued that a pterosaur or 'four-winged' dinosaur's hip would be able to get into this bat-like pose," Manafzadeh said. And that, she says, may require a rethinking of the evolution of flight in these animals.

In addition to calling into question traditional ideas about flight in pterosaurs and early birds, the research also provides new ways of assessing joint mobility for any joint of any extinct species by looking at its living relatives.

Read more at Science Daily

Danish Bone Trove Yields Earliest Evidence of Barbarian Battle

A femur, tibia, and fibula are among thousand of bones found on the Jutland peninsula in Denmark, where archaeologists believe an epic battle occurred 2,000 years ago.
Thousands of bones from boys and men likely killed in a ferocious battle 2,000 years ago have been unearthed from a bog in Denmark, researchers said Monday.

Without local written records to explain, or a battlefield to scour for evidence, experts are nevertheless piecing together a story of the Germanic people, often described by the Romans as "barbarians" for their violent nature.

Four pelvic bones strung on a stick were among the remains of at least 82 people found during archaeological excavations at Alken Enge, on Denmark's Jutland peninsula, indicating an organized and ritual clearing of a battlefield, said the report in the Proceedings of the National Academy of Sciences.

The site, which has been studied since 2009, has yielded the earliest discovery of "a large contingent of fighters from a defeated army from the early first century AD," said the PNAS report.

Well preserved

"The bones are extremely well preserved," co-author Mette Løvschal, of the department of archaeology and heritage studies at Aarhus University, told AFP.

"And you can see stuff that you can normally not see in them, like the gnaw marks of animals and you can see the cut marks from sharp weapons. That is highly unusual," she said.

The more than 2,300 human bones were contained in peat and lake sediments over 185 acres (75 hectares) of wetland meadows. Radiocarbon dating put them between 2 BC and 54 AD.

In this era, Roman soldiers were pressing an expansion northward, and around 7 AD, the Romans suffered a massive loss in which tens of thousands of warriors were killed by the Germanic people.

"What they do in the succeeding decades is have these military raids in Germania, basically to punish the barbarians for this huge defeat," said Løvschal. "What we actually think we are seeing here could be the remains of one of those punitive campaigns."

Young and old males

Løvschal said the bones appear to be from a "fairly heterogeneous population," with some as young as 13 to 14, and others as old as 40-60.

The bog is estimated to hold the remains of around 380 men who died from combat injuries.

"They do not seem to have a lot of healed trauma, from experience with previous battles," she said. "They could have had previously very little experience with battle."

Four pelvic bones threaded onto a stick, which are among thousands of bones found at the site of an ancient battle 2,000 years ago.
 The bones show weapon strikes predominantly on the right side, with few injuries around the midsection where the fighters may have been holding shields with their left arms.

Experts think the bodies may have been lying on the battlefield for quite some time, possibly six months to a year, because many bones show signs of being gnawed by dogs or wolves.

They were stripped of their personal belongings before being deposited into the bog.

Questions remain

Many questions remain. Who was involved in the battle? Was it tribe-against-tribe, or Germanic fighters against Roman warriors?

And what is the meaning of stringing pelvic bones on a stick?

"Those four pelvises on a stick could almost point to having connotations to sexual humiliation," said Løvschal. "It seems to have aggressive undertones to it as well. So it has been difficult to say who did it."

Archaeologists could also see another telling change in the landscape after the battle.

Read more at Seeker

May 22, 2018

Sweet potatoes didn't originate in the Americas as previously thought

A) Modern distribution of the sweet potato family (yellow line) and genus (white line). B) Fossil leaf of Ipomoea meghalayensis. C) Modern leaf of Ipomoea eriocarpa, showing similar size, shape and vein pattern.
Sweet potatoes may seem as American as Thanksgiving, but scientists have long debated whether their plant family originated in the Old or New World. New research by an Indiana University paleobotanist suggests it originated in Asia, and much earlier than previously known.

IU Bloomington emeritus professor David Dilcher and colleagues in India identified 57-milion-year-old leaf fossils from eastern India as being from the morning glory family, which includes sweet potatoes and many other plants. The research suggests the family originated in the late Paleocene epoch in the East Gondwana land mass that became part of Asia.

"I think this will change people's ideas," Dilcher said. "It will be a data point that is picked up and used in other work where researchers are trying to find the time of the evolution of major groups of flowering plants."

Previous fossil evidence had suggested the morning glory family may have originated in North America about 35 million years ago. But molecular analyses had supported the idea that it originated earlier and in the Old World. The new research provides evidence for that conclusion.

The discovery also suggests the morning glory family and the nightshade family, which includes potatoes and tomatoes, diverged earlier than previously thought. Together with the recent, separate discovery of 52-million-year-old nightshade fossils in Argentina, it suggests that morning glories developed in the East and nightshades in the West.

The 17 fossils analyzed in the study are the earliest recorded fossils for both the morning glory family, known as Convolvulaceae, and the order Solanales, which includes morning glories and nightshades. Morning glory fossils are rare because the plants' soft structure was not easily preserved in rocks.

Dilcher's collaborators, Gaurav Srivastava and Rakesh C. Mehrotra of India's Birbal Sahni Institute of Palaeosciences, discovered the fossils in Meghalaya, a state in northeastern India.

The researchers used microscopic analysis of the shape and structure of the leaves, comparing details of the leaf veins and cells with plants in the genus Ipomoea. Using such analysis to examine evolutionary relationships has been a hallmark of Dilcher's paleobotany research career.

The leaves the researchers studied are in the genus Ipomoea, which includes sweet potato but also hundreds of other plants, most of which don't produce food for humans.

"We don't know that these were sweet potatoes," said Dilcher, emeritus professor in the Department of Earth and Atmospheric Sciences and the Department of Biology in the IU Bloomington College of Arts and Sciences. "We can't say there were delicious sweet potatoes there. There may have been, or there may not."

Read more at Science Daily

Michael Jackson's antigravity tilt -- Talent, magic, or a bit of both?

When was the last time you watched a Michael Jackson music video? If your answer is "never" or "not for quite a while," you are really missing a treat. According to Rolling Stone, "No single artist ... shaped, innovated or defined the medium of 'music video' more than Michael Jackson."

Back in the 1980s and early 1990s, MTV had only one format -- music videos -- and that genre really took off when Jackson burst on the scene in 1983 with his musical hit "Billie Jean." Prior to his arrival on MTV, most videos were merely visual promos for artists' songs, and in some cases the visual side of the promos detracted from the music. Michael Jackson, on the other hand, took his incredible music and added story lines, special effects, cinematography, and amazing choreography. He created high-budget brief movies highlighting both music and dance.

And about that dance. . . . Jackson executed dance moves we thought impossible, at the time and even now. Almost every fan tried to dance like him, but very few could pull it off. Some of Jackson's dance moves appear to defy the laws of gravity. In one move featured in his 1987 music video "Smooth Criminal," he pitches forward 45 degrees, with his body straight as a rod and his shoes resting on the stage, and holds the position. That is not how the human body works! How did Michael Jackson do it? Was it talent, magic, or both?

Three neurosurgeons from the Postgraduate Institute of Medical Education and Research in Chandigarh, India -- Nishant S. Yagnick, Manjul Tripathi, and Sandeep Mohindra -- set out to examine the antigravity tilt introduced in "Smooth Criminal" from a neurosurgeon's point of view.

First, Yagnick et al. walk us through some basics of spinal biomechanics to show just how impressive is the feat. Even the strongest of dancers can only maintain a 25- to 30-degree forward tilt from the ankle.

Admitted fans of Jackson, the neurosurgeons document how the antigravity tilt was accomplished, taking into account the talent and core strength of the artist, as well as his inventiveness and use of a patented aid, that together seem to move his body past human limits. They also warn other neurosurgeons of new forms of spinal injuries, as dancers follow Jackson's example and attempt "to jump higher, stretch further, and turn faster than ever before."

The full story on the antigravity tilt is published today in a new article in the Journal of Neurosurgery entitled "How did Michael Jackson challenge our understanding of spine biomechanics?."

Read the article soon. This is one of those mysteries where the solution is as fascinating as the performance. After you've read the article, you may want to go to YouTube and check out "Smooth Criminal" and other Michael Jackson music videos.

Read more at Science Daily