Aug 6, 2016

Kepler's 'Alien Megastructure' Star Just Got Weirder

You're probably all too familiar with the story of KIC 8462852, a star that's been the focus of much speculation and excitement over the past few months.

KIC 8462852 was observed by NASA's Kepler mission and has become infamous for its bizarre and unprecedented transit signal that was flagged by citizen scientists. Now new research of precision Kepler observations has shown that the overall brightness of the star -- unofficially named "Tabby's Star" after astronomer Tabetha S. Boyajian who discovered the peculiar signal -- has been decreasing, which poses a new and confusing problem for astronomers trying to understand what the heck is going on.

Kepler's prime mission is to look for small worlds that pass in front of their parent stars causing a slight dimming of starlight. The "transit method" has been hugely successful and has confirmed well over 2,000 planets orbiting other stars in our galaxy.

But Tabby's Star's transit signal, otherwise known as a "light-curve", stopped astronomers in their tracks. Something passed in front of it, dimming its starlight a whopping 20 percent and other jumbled transit signals revealed that something wasn't quite right with this particular star. Then, in an interview with The Atlantic, Penn State University astronomer Jason Wright speculated that the signal could be indicative of an "alien megastructure" that's in the process of being built. You can catch up on the controversy surrounding the anomalous signal in my recent Discovery News article "Closing In on 'Alien Megastructure' Clues."

So, until now the leading (natural) explanation of the strange light-curve has focused on the possibility of a huge swarm of comets passing in front of the star, blocking a substantial portion of starlight from Kepler's optics. Recently, this hypothesis was given a little more credence after observations by the Submillimeter Array and the James Clerk Maxwell Telescope in Hawaii revealed little evidence it might be caused by the debris cloud of some planetary spashup. But the "swarm of comets" explanation still fell short of fully explaining the phenomenon, though for now it remains the leading rationale.

All this uncertainty has only boosted speculation surrounding the (unnatural) explanation: that an advanced alien civilization is building some kind of Dyson Sphere-like structure around a star to (perhaps) collect solar energy for all their energy consumption needs. In this scenario, pieces of the alien array are passing in front of the star, causing the anomalous transit signal. Of course, scientists being a rational bunch think there's a more likely explanation for the light-curve, but aliens always seem to hog headlines.

So, in an effort to track down a rational explanation, Bradley Schaefer from Louisiana State University decided to study historical observations of KIC 8462852 in astronomical photographic plates from the past century to see if the star exhibited any bizarre fluctuations in brightness in the past. Sure enough, yes, the star is a bit of an oddball and has shown a long-term decreasing trend in brightness! Since the 19th Century, its brightness has decreased steadily by nearly 20 percent.

Now, astronomers Ben Montet (from Caltech) and Joshua Simon (from the Carnegie Institute) have released a paper to the arXiv preprint service detailing recent Kepler observations of KIC 8462852 since the space telescope was launched in 2009. Although the dataset for this time period is comparatively small, Monet and Simon found yet another surprise.

In the 4 years of Kepler's primary mission, the star showed an unprecedented dimming of 3.5 percent. So not only did Kepler detect transient dips in brightness of up to 20 percent, there also seems to be a very definite downward trend in brightness throughout our observational history of the star.

No matter how you slice it, this is strange.

After studying photometric observations for other stars surrounding KIC 8462852, there's no other star that shows such dramatic behavior. What's more, there's very few known phenomena that could be causing this. So once again, astronomers are clutching at straws in an effort to explain what is going on.

"Broadly speaking, the morphology of the light curve is generally consistent with the transit of a cloud of optically thick material orbiting the star," Monet and Simon write in their paper. "The breakup of a small body or a recent collision that could produce a cloud of material could also plausibly produce a family of comets that transit the host star together as one group, explaining the light curve..."

Read more at Discovery News

New 'Echo Hunter' Whale Species Had Ultrasonic Hearing

Sound is produced by Echovenator sandersi, which bounces off prey to create echoes. This illustration shows how these echoes are detected via conduction of vibrations through the mandible and received by the whale's inner ear.
A new whale species with the name "Echo Hunter" (Echovenator sandersi), for its super-hearing, has just been described, and it's helping researchers gain new insight into the evolution of high-frequency hearing in the the earliest whales.

The finding comes thanks to a fossil, dated to 27 million years ago, that includes a highly-intact skull. It was examined by researchers from the New York Institute of Technology (NYIT), who got the chance to study what they say is one of the most well preserved fossils ever found of a whale's ear.

And what an ear. Aided by uniquely shaped inner ear structures, the whale could hear sounds far outside the range of human ears.

"This was a small, toothed whale that probably used its remarkable sense of hearing to find and pursue fish, with echoes only," explained study co-author Jonathan Geisler, an NYIT associate professor, in a statement.

High-frequency hearing capability is a necessary feature of all toothed whales, which use it in conjunction with echoes of their own calls in order to echolocate – using sound to map out their surroundings and navigate and seek food. Bats use it. So do dolphins.

"This would allow it to hunt at night," said Geisler. "But, more importantly, it could hunt at great depths in darkness, or in very sediment-choked environments."

The NYIT researchers say their study shows that most of the features for high-frequency hearing in the animals were in place 27 million years ago, around the same time that echolocation evolved. Some features might have even evolved earlier than that.

"Previous studies have looked at hearing in whales but our study incorporates data from an animal with a very complete skull," said postdoctoral fellow Morgan Churchill, the lead author of the study.

"The data we gathered enabled us to conclude that it could hear at very high frequencies," he noted, "and we can also say with a great degree of certainty where it fits in the tree of life for whales."

Detailed findings about the new species and its hearing have been published in the journal Current Biology.

From Discovery News

Aug 5, 2016

Veins on Mars were formed by evaporating ancient lakes

Drill hole into the John Klein target within Sheepbed Member of Yellowknife Bay, with a light-toned sulfate veinlet visible on the back wall. The light-toned veins have been identified as sulfates by ChemCam (Nachon et al.; Schroeder et al.) and CheMin (Vaniman et al.). Drill hole is 1.6 cm diameter. Image is white balanced. Scale bar is 2 cm.
Mineral veins found in Mars's Gale Crater were formed by the evaporation of ancient Martian lakes, a new study has shown.

The research, by Mars Science Laboratory Participating Scientists at The Open University and the University of Leicester, used the Mars Curiosity rover to explore Yellowknife Bay in Gale Crater on Mars, examining the mineralogy of veins that were paths for groundwater in mudstones.

The study suggests that the veins formed as the sediments from the ancient lake were buried, heated to about 50 degrees Celsius and corroded.

Professor John Bridges from the University of Leicester Department of Physics and Astronomy said: "The taste of this Martian groundwater would be rather unpleasant, with about 20 times the content of sulphate and sodium than bottled mineral water for instance!

"However as Dr Schwenzer from The Open University concludes, some microbes on Earth do like sulphur and iron rich fluids, because they can use those two elements to gain energy. Therefore, for the question of habitability at Gale Crater the taste of the water is very exciting news."

The researchers suggest that evaporation of ancient lakes in the Yellowknife Bay would have led to the formation of silica and sulphate-rich deposits.

Subsequent dissolution by groundwater of these deposits -- which the team predict are present in the Gale Crater sedimentary succession -- led to the formation of pure sulphate veins within the Yellowknife Bay mudstone.

The study predicts the original precipitate was likely gypsum, which dehydrated during the lake's burial.

The team compared the Gale Crater waters with fluids modelled for Martian meteorites shergottites, nakhlites and the ancient meteorite ALH 84001, as well as rocks analysed by the Mars Exploration rovers and with terrestrial ground and surface waters.

The aqueous solution present during sediment alteration associated with mineral vein formation at Gale Crater was found to be high in sodium, potassium and silicon, but had low magnesium, iron and aluminium concentrations and had a near neutral to alkaline pH level.

The mudstones with sulphate veins in the Gale Crater were also found to be close in composition to rocks in Watchet Bay in North Devon, highlighting a terrestrial analogue which supports the model of dissolution of a mixed silica and sulphate-rich shallow horizon to form pure sulphate veins.

Read more at Science Daily

Do black holes have a back door?

An artist's drawing a black hole named Cygnus X-1. It formed when a large star caved in. This black hole pulls matter from blue star beside it.
One of the biggest problems when studying black holes is that the laws of physics as we know them cease to apply in their deepest regions. Large quantities of matter and energy concentrate in an infinitely small space, the gravitational singularity, where space-time curves towards infinity and all matter is destroyed. Or is it? A recent study by researchers at the Institute of of Corpuscular Physics (IFIC, CSIC-UV) in Valencia suggests that matter might in fact survive its foray into these space objects and come out the other side.

Published in the journal Classical and Quantum Gravity, the Valencian physicists propose considering the singularity as if it were an imperfection in the geometric structure of space-time. And by doing so they resolve the problem of the infinite, space-deforming gravitational pull.

"Black holes are a theoretical laboratory for trying out new ideas about gravity," says Gonzalo Olmo, a Ramón y Cajal grant researcher at the Universitat de València (University of Valencia, UV). Alongside Diego Rubiera, from the University of Lisbon, and Antonio Sánchez, PhD student also at the UV, Olmo's research sees him analysing black holes using theories besides general relativity (GR).

Specifically, in this work he has applied geometric structures similar to those of a crystal or graphene layer, not typically used to describe black holes, since these geometries better match what happens inside a black hole: "Just as crystals have imperfections in their microscopic structure, the central region of a black hole can be interpreted as an anomaly in space-time, which requires new geometric elements in order to be able to describe them more precisely. We explored all possible options, taking inspiration from facts observed in nature."

Using these new geometries, the researchers obtained a description of black holes whereby the centre point becomes a very small spherical surface. This surface is interpreted as the existence of a wormhole within the black hole. "Our theory naturally resolves several problems in the interpretation of electrically-charged black holes," Olmo explains. "In the first instance we resolve the problem of the singularity, since there is a door at the centre of the black hole, the wormhole, through which space and time can continue."

This study is based on one of the simplest known types of black hole, rotationless and electrically-charged. The wormhole predicted by the equations is smaller than an atomic nucleus, but gets bigger the bigger the charge stored in the black hole. So, a hypothetical traveller entering a black hole of this kind would be stretched to the extreme, or "spaghettified," and would be able to enter the wormhole. Upon exiting they would be compacted back to their normal size.

Seen from outside, these forces of stretching and compaction would seem infinite, but the traveller himself, living it first-hand, would experience only extremely intense, and not infinite, forces. It is unlikely that the star of Interstellar would survive a journey like this, but the model proposed by IFIC researchers posits that matter would not be lost inside the singularity, but rather would be expelled out the other side through the wormhole at its centre to another region of the universe.

Another problem that this interpretation resolves, according to Olmo, is the need to use exotic energy sources to generate wormholes. In Einstein's theory of gravity, these "doors" only appear in the presence of matter with unusual properties (a negative energy pressure or density), something which has never been observed. "In our theory, the wormhole appears out of ordinary matter and energy, such as an electric field" (Olmo).

Read more at Science Daily

Scientists discover light could exist in a previously unknown form

Artistic image of light trapped on the surface of a nanoparticle topological insulator.
New research suggests that it is possible to create a new form of light by binding light to a single electron, combining the properties of both.

According to the scientists behind the study, from Imperial College London, the coupled light and electron would have properties that could lead to circuits that work with packages of light -- photons -- instead of electrons.

It would also allow researchers to study quantum physical phenomena, which govern particles smaller than atoms, on a visible scale.

In normal materials, light interacts with a whole host of electrons present on the surface and within the material. But by using theoretical physics to model the behaviour of light and a recently-discovered class of materials known as topological insulators, Imperial researchers have found that it could interact with just one electron on the surface.

This would create a coupling that merges some of the properties of the light and the electron. Normally, light travels in a straight line, but when bound to the electron it would instead follow its path, tracing the surface of the material.

In the study, published today in Nature Communications, Dr Vincenzo Giannini and colleagues modelled this interaction around a nanoparticle -- a small sphere below 0.00000001 metres in diameter -- made of a topological insulator.

Their models showed that as well as the light taking the property of the electron and circulating the particle, the electron would also take on some of the properties of the light.

Normally, as electrons are travelling along materials, such as electrical circuits, they will stop when faced with a defect. However, Dr Giannini's team discovered that even if there were imperfections in the surface of the nanoparticle, the electron would still be able to travel onwards with the aid of the light.

If this could be adapted into photonic circuits, they would be more robust and less vulnerable to disruption and physical imperfections.

Dr Giannini said: "The results of this research will have a huge impact on the way we conceive light. Topological insulators were only discovered in the last decade, but are already providing us with new phenomena to study and new ways to explore important concepts in physics."

Dr Giannini added that it should be possible to observe the phenomena he has modelled in experiments using current technology, and the team is working with experimental physicists to make this a reality.

Read more at Science Daily

Macaques Grin in Sleep, Push Back Origin of Smiles

Baby macaques have been caught smiling for no good reason, even in their sleep, which means monkeys can join the small club of documented so-called "spontaneous smilers."

That's according to a new study from Kyoto University's Primate Research Institute, where researchers observed several dozen smiles from seven macaque newborns.

Spontaneous smiles in infants – facial movements that frequently happen during sleep and have no discernible cause, internally or externally – have, of course, been seen in humans and also, more recently, in chimpanzees.

"About a decade ago we found that chimp infants also display spontaneous smiles," said study co-author Masaki Tomonaga in a statement. "Since we see the same behavior in more distant relatives, we can infer that the origin of smiles goes back at least 30 million years, when old world monkeys and our direct ancestors diverged."

The study's lead author, Fumito Kawakami, noticed macaque newborns smiling during health exams, and that prompted a closer look at the behavior, culminating in a study just published in the journal Primates.

As can be seen in the video, the word "smiling" is used broadly, when compared with the everyday impression of what constitutes, say, a human smile.

"Spontaneous macaque smiles are more like short, lop-sided spasms compared to those of human infants," explained Kawakami.

Read more at Discovery News

Aug 4, 2016

Lasers melt rocks to reveal development of super-Earths and how giant impacts make magma

High-powered lasers melt mineral for planet formation experiments. Researchers observed the melting of forsterite, the most common constituent of Earth's mantle, to understand how the cores of planets form and develop. The laser is able to create pressures representative of the extreme collisions between objects in space. The target is a 4 millimeter square. Al is aluminum and Qz is quartz. Image by Toshimori Sekine, Hiroshima University. Image may only be re-used with attribution.
New experiments provide insight into how Earth-type planets form when giant asteroids or planetesimals collide and how the interiors of such planets develop. Researchers at Hiroshima University, Osaka University, Ehime University, University of Tokyo, and the Chiba Institute of Technology collaborated to publish their research in the August 3, 2016 issue of Science Advances.

"Our results provide a better understanding how impact-generated magmas evolve and allow us to model Earth-type planets' inner structures. Collisions at these extreme temperatures and pressures created our own Earth and may have also formed the mantles of other Super Earth planets, for example CoRoT-7b and Kepler-10b," said Toshimori Sekine, Ph.D., first author of the research paper and Professor at Hiroshima University.

These powerful collisions cause chemical reactions within the giant rocks and knowing what types of reactions occur under what conditions gives researchers a better understanding of the development of planets too far away for satellites to explore. Many of the rocks include forsterite, a representative mineral that makes up much of the matter in space. Forsterite, known to scientists as Mg2SiO4, is a combination of Magnesium, Silicone, and Oxygen and is the most abundant constituent of Earth's mantle, the layer between the surface crust and molten core.

The research team of geophysicists and engineers successfully measured the melting of forsterite. However, replicating the intense collisions that can turn minerals into magma in Earth-based experiments was a challenge.

"The laser shock technique was first used in the 1990s, but the results were not precise. Recent technical advances enable us to measure precisely the laser-shocked states," said Sekine.

The laser shock technique uses a high-power laser to irradiate a target, which was a block of forsterite in the experiments by Sekine's team. The energy of the irradiation causes an abrupt expansion of the target's molecules and the inertia of this expansion generates a shock wave. The energy from the shock wave can create heat and light that melts and reflects off of the forsterite.

Previous studies without the laser shock technique only measured the properties of forsterite at shock pressures below 200 Giga Pascals (GPa). The new experiments put forsterite crystals under pressures between approximately 250 and 970 GPa. For comparison, the pressure at the center of Earth is estimated to be 360 GPa.

Researchers measured the pressure, temperature, density, and reflectivity of laser-shocked forsterite. These parameters did not increase at a constant rate as the pressure steadily increased, revealing that both energy producing and energy absorbing reactions occur in shocked forsterite melt at pressures between 250 GPa and 344 GPa.

Earlier research has connected magnesium oxide, one of the minerals that is formed from forsterite, to the reactions necessary for a planet to develop a magnetic field that persists for a long geological time, such as the magnetic field of Earth. With these new details of forsterite's melting behavior, researchers may be able to predict how minerals separate into different layers of magma and which minerals may be close enough to react.

Read more at Science Daily

Evidence for China's Great Flood Found

Researchers have found the first evidence for the legendary Great Flood on the Yellow River, a massive, catastrophic event that occurred about 4,000 years ago and ultimately produced the first dynasty of China.

Folk traditions and written records recount how the hero Yu dredged and tamed the destructive floodwaters about 4,000 years ago.

Yu's decades-long feat earned him "the divine mandate to establish the Xia dynasty, the first in Chinese history, and marked the beginning of Chinese civilization," Qinglong Wu, a researcher at Peking University and Nanjing Normal University, China, and colleagues wrote in Science.

Until now no direct evidence of the cataclysm had been discovered.

"In the absence of geological evidence for such a flood, some scholars have argued that the story is either a historicized version of an older myth or propaganda to justify the centralized power of imperial rule," David Montgomery, professor of Earth and Space Sciences at the University of Washington in Seattle, wrote in a related Science paper.

Mapping distinctive sediments that are widely distributed along the Yellow River valley, Wu and colleagues were able to reconstruct the sequence of events that led to the flood. The sediments included deposits sourced from the gorge upstream.

"They are the direct and solid evidence of a great flood. Only a large flood can deposits such sediments," Wu told Discovery News.

According to the researchers, it all began with an earthquake which destroyed the Lajia site, a settlement of the Qijia culture, which is famous for having produced the world's earliest noodles.

Cave dwellings at Lajia collapsed, killing all the people there.

But the quake was even more destructive. It triggered a massive rock slide that dammed the river and backed up a lake.

"The lake was at least 200 meters (approx. 650 feet) deep," Purdue University professor Darryl Granger said.

Within six to nine months, the lake overflowed and the landslide dam failed catastrophically, sweeping over the Lajia site.

The researchers were able to determine the dimension of the flood channel and exactly how high the flood waters reached.

"The evidence found in our investigations along the Yellow River in Qinghai Province includes remains of a landslide dam, dammed lake sediments upstream, and outburst flood sediments downstream that allow us to reconstruct the size of the lake and flood," the researchers wrote.

The ancient landslide dam deposits reach an elevation of 785 feet above the present river level and stretch for more than 4,200 feet along Jishi Gorge.

Overall, the flood that broke the dam was of enormous proportions.

"It was about 300-500,000 cubic meters per second. To put that into perspective, it is among the largest known floods to have happened on Earth during the past 10,000 years," Granger said.

Using radiocarbon dating techniques on samples that included the skeletons of children who died in the earthquake at Lajia, the researchers dated the flood to 1920 B.C.

Read more at Discovery News

Sunflowers Sway to Summer's Rhythms

Mature sunflowers are remarkable for their uniform eastward orientation.
Young sunflowers do what looks like a slow dance each day, turning and swaying of their own apparent volition, and now new research finds that these moves are driven by the sun, plant hormones and the sunflowers' internal clock.

This behavior of sunflowers was noticed way back in 1898, but the new study -- published in the journal Science -- is the first to explain in detail why it happens. The study is also the first to show that internal clock regulation of growth promotes overall plant yield, which in this case can lead to hefty, leafy tall sunflowers.

A field of sunflowers in Lopburi, Thailand.
The findings add to growing evidence that plants are more animal-like than most of us might think.

"Plants are exquisitely sensitive to the environment -- that is how they survive while stuck in one place -- and have senses very analogous to all the human senses," senior author Stacey Harmer, a professor in the University of California at Davis' Department of Plant Biology, told Discovery News. "For me, the big difference is the time scale of many of the responses."

"Plants actually have color vision," she continued. "They have several families of photoreceptors that allow them to see many different wavelengths of light: UV, blue, green, red, far-red … . Note that plants can see wavelengths of light that humans can't detect (UV and far-red). They use these photoreceptors, in particular, those that are sensitive to blue light, to track the sun."

Growing sunflowers "watch" the sun and move with it, beginning their days with their heads facing east, swinging west throughout the day, and turning back to the east at night.

For the study, funded by the National Science Foundation's Plant Genome Research Program, Harmer and postdocs Hagop Atamian and Nicky Creux joined forces with scientist Benjamin Blackman and his lab members Evan Brown and Austin Garner.

Atamian, collaborating with other members of the team, carried out a series of experiments on sunflowers in the field, in pots outdoors and in indoor growth chambers.

By staking plants so that they could not move, or turning potted plants around daily so that they were facing the wrong way, Atamian showed that he could disrupt their ability to track the sun. He also noticed that sunflowers prevented from moving were not as bulky and leafy as those that were free to move.

A sunflower just prior to bud opening.
When plants were moved into an indoor growth chamber with an immobile overhead light, they continued to swing back and forth for a few days, which Harmer said is what would be expected when behavior is driven by an internal clock.

The indoor plants did start tracking the "sun" again when the apparent source of lighting was moved across the growth chamber by turning adjacent lights on and off during the day. The plants could reliably track the movement and return at night when the artificial day was close to a 24-hour cycle, but not when it was closer to 30 hours.

Next, Atamian put ink dots on some sunflower stems and filmed them. Using time-lapse video, he measured the changing distance between the dots and determined that when sunflowers track the sun, the east sides of their stems grew more rapidly than the west sides. At night, the west sides grew faster as the stem swung the other way.

Harmer explained that, as a result, "the back and forth rhythmic growth of sunflowers is due to asymmetrical growth on the opposite sides of the stem."

Read more at Discovery News

Teeny Radar Antenna Tracks the Flight of the Bumblebee

For the first time, scientists have tracked the flight paths of bumblebees over the span of their entire lives.

Not only do the results help biologists better understand bee behavior, but because the insects play a critical role in pollinating crops, understanding their movements could improve how farmers manage agriculture.

Joseph Woodgate of Queen Mary University of London and his colleagues used radar to monitor the daily flight patterns of four different bees, from the time they first left their nests to the time they ceased to return.

Because only one bee could be tracked at a time with the radar, the researchers set out four different colonies at four different times, tracking one bee each time.

"For the first time, we have been able to record the complete 'life story' of a bee," study coordinator Lars Chittka said in a press release. "From the first time she saw the light of day, entirely naive to the world around her, to being a seasoned veteran forager in an environment full of sweet nectar rewards and dangerous threats, to her likely death at the hands of predators, or getting lost because she has ventured too far from her native nest."

To monitor the insects, the scientists affixed a radar transponder just 16 millimeters tall to each bee using superglue. The antenna didn't harm the bee or interfere with its normal activities as it spent its days foraging a field of wild flowers and thistle in Hertfordshire, UK.

From those four bees, the scientists gathered data from 244 flights, adding up to 15,000 minutes of flight and covering 111 miles.

Previous studies had shown that foraging bumblebees tended to explore the area looking for food or exploit it, settling down to harvest. But how long they explored vs exploited was unknown.

"One of the most striking results to emerge," the researchers say in their paper published today in the journal PLOS ONE, "is the large degree to which our bees differed from one another."

All the flights undertaken by four different bees (panels A, B, C, and D) throughout their lives. Green indicates exploratory paths; blue shows looping flights close to the nest; yellow and orange show the bees exploiting good forage.
For example, Bee 1 spent a much higher proportion of her time exploiting -- more than 90 percent. But Bees 2 and 3 spent more time exploring. Bees 1 and 3 didn't travel as far as 2 and 4 in their explorations. Bees 1 and 4 switched the destination of their flights over the course of their foraging and never returned to the first location they foraged.

Read more at Discovery News

Aug 3, 2016

Captain Cook Delivered First Chickens to New Zealand

A study published today in Royal Society Open Science used radiocarbon dating and DNA analysis to determine the age and origin of ancient chicken bones from three archaeological sites on New Zealand's South Island.

The researchers found that the age of the bones from two of the sites coincided almost exactly with Captain Cook's 1773 expedition to the area.

This predates regular European visitations by about 30 years but is also far later than Polynesian settlement, which happened sometime between AD1000-1300.

The bones from a third site were younger, their age corresponding more closely to early sealing expeditions.

Geneticist and co-author Dr Michael Herrera, from the University of Adelaide, said chickens were a common species brought along by voyagers as a source of food.

"When the first Polynesians were exploring or settling in the Pacific, they had to have a survival strategy and part of that strategy was to bring chickens to snack on or establish in the new environment," Dr Herrera said.

Early Polynesian settlers were known to have established chicken colonies in other parts of the East Polynesian archipelago.

Chicken bones corresponding to that early settlement period have been found on islands such as Hawaii and Easter Island, however New Zealand appeared to have remained chicken-free.

Dr Herrera said one reason for the lack of chicken on New Zealand during early Polynesian settlement may have been the abundance of food already available there.

That left it up to Captain Cook to be the first to truly liberate Gallus gallus domesticus into New Zealand.

Analysis of Captain Cook's records revealed that the expedition acquired chickens during a stop at the Cape Verde islands off the west coast of Africa, and may also have brought them from England, South Africa, Tahiti and Tonga on the way to New Zealand.

The travellers then gifted several pairs of roosters and hens to Maori chiefs, close to the areas where the bones were found.

Although Captain Cook reported he had little confidence the birds would survive, one year after chickens were released at West Bay in Marlborough Sound, a fresh hen's egg was found there.

Read more at Discovery News

Gravitational Waves to Crack Neutron Star Mystery

We are now in an incredible new era of astronomy where the faint ripples in spacetime caused by distant black hole collisions are being detected and studied. These are the most energetic events in the cosmos and, by "listening in" to their gravitational wave signals, these black hole mergers have finally been directly observed.

Although the first detections of gravitational waves by the Laser Interferometer Gravitational-wave Observatory (LIGO) have, so far, been exclusive to the collisions of black holes, astrophysicists have far loftier goals. The next step will be to detect the collisions of neutron stars and, hopefully, use their gravitational wave signals to crack open the super-dense husks of stellar matter, revealing what they are really made of.

Gravitational waves traveling through spacetime can be imagined as ripples traveling across the surface of a pond. And, like those water ripples, gravitational waves carry energy away from massive objects that accelerate, collide or explode. The historic Feb. 11 announcement of the detection of gravitational waves that were recorded by LIGO on Sept. 14, 2015, revealed the first direct observation of two black holes, one 29 solar masses and another 36 solar masses, colliding and merging as one.

Then, on June 14, a second detection was announced, revealing yet another black hole merger. Only this time the black holes were smaller, "weighing in" at 14 solar masses and 8 solar masses.

Both observations revealed an astonishing amount of information about the pairs of black holes before and after their powerful collisions, including the fact they were spinning and their precise masses. What's more, the gravitational wave signals were very much in line with our theoretical predictions of what gravitational waves generated by black hole mergers should look like. These first detections are a testament to our theoretical understanding of black holes, considering that, up until Sept. 15, 2015, we'd never actually observed any kind of direct signal from a black hole (though we already had an abundance of indirect evidence that black holes and gravitational waves were physically out there).

So, we have direct observational proof of the existence of gravitational waves (and, indeed, black holes themselves) and we now know we can build laser interferometers sensitive enough to detect the most minuscule fluctuations in spacetime. Now astrophysicists want to probe even deeper in the hope of detecting the collisions of neutron stars, which are a few orders of magnitude less massive than black holes and their gravitational waves will be much fainter.

Neutron stars are created after massive stars run out of fuel and explode as supernovae. After the stellar fireworks, a tiny spinning mass of ultradense matter may be left behind. The intense gravity of this neutron star crushes normal matter into an extreme state governed by quantum dynamics. Thought to be a massive ball of neutrons -- subatomic particles found in the nuclei of normal atoms -- a neutron star can be thought of as a giant atom unto itself; a massive nucleus composed of only neutrons trapped in a crushing gravitational field, spinning fast and often possessing a powerful stellar magnetic field.

Some of these neutron stars can turn into pulsars, blasting intense radiation from their magnetic poles, appearing as flashing lighthouses in the universe.

However, there are many unanswered questions in the field of neutron star physics. One key question is whether neutron stars fit the "textbook" explanation of what a neutron star is -- basically a ball of neutrons -- or have the neutrons themselves been crushed into oblivion and other quantum rules are being applied? Could neutron stars actually be an ultra-dense ball of quarks, the even smaller subatomic particles that make up the neutrons themselves?

Before Feb. 11, these questions would have remained a theoretical curiosity, but now we have a natural probe into some of the most massive objects in the universe and gravitational waves could be used to reveal the hearts of colliding neutron stars, possibly cracking them open and revealing the physics that lie within.

"Ultimately, (gravitational waves) may answer the question, whether neutron stars are composed solely of ordinary atomic nuclei, or if they contain more exotic matter in the form of dense deconfined quark matter," said physicist Aleksi Vuorinen, of the University of Helsinki, Finland, in a statement.

The key problem with trying to understand neutron star physics is that there is currently no way we can simulate the extreme conditions neutron star matter experiences on Earth. The closest we can come is to collide particles inside powerful accelerators like the Large Hadron Collider (LHC) near Geneva, Switzerland, to produce a very short-lived, hot quark-gluon plasma. Though particle collisions may reveal some qualities of this exotic state of matter, governed by Quantum Chromodynamics (QCD), it comes woefully short of simulating a neutron star's dense environment.

"The quark-gluon plasma that is produced in heavy ion collisions can be thought of as a hot but not very dense soup of quarks and gluons, while quark matter is a very dense and cold, essentially solid state, of matter," said Aleksi Kurkela (from CERN and the University of Stavanger in Norway) in an interview with "Our work in fact bridges the gap between these two systems, as our result is applicable at all temperatures, unlike any of the previous results."

So it seems likely that the only way we can "see" what neutron stars are made of would be to try to detect the gravitational wave signals generated after two neutron stars collide. But once we do detect the first gravitational waves generated by neutron star mergers, we need to decipher what the signal actually means, and this is why Vuorinen and Kurkela are working on some pretty exciting simulations of neutron star smashups.

Read more at Discovery News

Dinosaurs Likely Saw Shades of Red

Dinosaurs likely had a gene that gave them a double win — red coloring and the ability to see the color red, a new study finds.

This so-called "red gene" gives living dinosaur relatives, including birds and turtles, red coloring on their bodies and the ability to see more colors within the red spectrum than people can see, the researchers said.

"Humans can distinguish between some shades of red such as scarlet and crimson. However, birds and turtles can see a host of intermediate reds between these two shades," study senior author Nick Mundy, an evolutionary geneticist at the University of Cambridge, said in a statement. "Our work suggests that dinosaurs would have also had this ability to see a wide spectrum of redness."

The gene, called CYP2J19, allows birds and turtles to convert yellow pigments they eat into red hues on their bodies, shells or beaks. These red pigments can also be used to strengthen their ability to see red through droplets of red oil in their retinas (the light-sensitive tissue at the back of the eye), the researchers said. [Paleo-Art: Dinosaurs Come to Life in Stunning Illustrations]

Unlike mammals, birds and turtles have retinal cones that contain brightly colored oil droplets, such as green, yellow and red, that help them see those colors, the researchers said. The oil droplets are akin to a color filter on a camera lens. "By filtering the incoming light, the oil droplets lead to greater separation of the range of wavelengths that each cone responds to, creating much better color sensitivity," Mundy said in the statement.

To learn about the evolutionary history of the CYP2J19 gene, the researchers reconstructed a family tree that dated back millions of years, and found that the "red gene" originated about 250 million years ago.

That's before turtles broke off from the archosaur line, a group that includes crocodiles, dinosaurs and birds, the researchers said. Given that the gene is older than dinosaurs themselves (the first dinosaurs appeared between 245 million and 240 million years ago), it's likely that dinosaurs also carried this "red gene" and the enhanced red vision that it enabled, the researchers said.

It's also possible that the gene gave some dinosaurs red coloring, but this is more speculative, the researchers said.

Seeing red may have helped dinosaurs pick the best mates, the researchers speculated.

Research on zebra finches, which also hold this red gene, suggests that redder birds are healthier. That's because there may be a link between red beaks and the bird's ability to break down toxins in the body, the researchers said. There is similar evidence among red-eared terrapins (freshwater turtles) suggesting that terrapins with redder ears are healthier than their less-rosy counterparts.

"The excellent red spectrum vision provided by the CYP2J19 gene would help female birds and turtles pick the brightest red males," the study's lead author, Hanlu Twyman, a doctoral student in the Department of Zoology at the University of Cambridge in England, said in the statement.

Read more at Discovery News

Septic Arthritis Seen in Dinosaur

Hadrosaur-like dinosaurs envisioned in their environment with other dinosaurs.
A long-gone duck-billed dinosaur has just been diagnosed with a horrific medical condition: septic arthritis.

The discovery, a first for dinosaurs, reveals that even prehistoric animals suffered from septic arthritis, a painful joint infection still seen in some modern birds, crocodiles and people. The findings are published in the journal Royal Society Open Science.

Lead author Jennifer Anné of the University of Manchester told Discovery News that "arthritis has been noted in a wide range of dinosaurs, and other animals, both modern and fossil. Septic arthritis represents further complications caused by arthritis in the form of infection."

She and colleagues Brandon Hedrick and Jason Schein used the microCT scanning facilities at the Center for Nanoscale Systems at Harvard University to analyze the remains of a hadrosaur unearthed at the Navesink Formation in New Jersey. The dinosaur lived about 70 million years ago.

Hadrosaurus mount at the Academy of Natural Sciences, Drexel University.
Hadrosaurs were plant eaters with duck-like bills and strong jaws evolved for grinding plants with their multiple rows of teeth. Many such dinosaurs sported massive crests on their heads, believed to be used for displays before mating.

The scientists found that their hadrosaur had septic arthritis in its elbow that caused a fused joint covered in bony growths. Germs, as from a bacterial or fungal infection, can appear in this infection if they travel through the bloodstream and reach one or more joints. A penetrating injury can also deliver germs directly to a joint.

The scientists believe that the hadrosaur suffered from the condition for some time before it died.

Anné said that "having a destroyed or possibly fused elbow would have (made) that arm fairly useless. I imagine he/she had a bit of limp going on, or perhaps didn't even put weight on that arm."

She continued that septic arthritis is similar to osteomyelitis, an infection of the bone and bone marrow that can cause inflammation and destruction of the bone. Osteomyelitis previously was detected in dinosaurs.

Unlike that condition, septic arthritis is due to an infection that starts outside of the bone. The researchers were able to rule out osteomyelitis due to the observed condition's location around the dinosaur's elbow joint and because of the nature of the associated bone growth.

Read more at Discovery News

Aug 2, 2016

Faintest hisses from space reveal famous star's past life

The supernova shock front as it pushes material from the blue and red supergiant phases.
Astronomers have managed to peer into the past of a nearby star millions of years before its famous explosion, using a telescope in remote outback Australia at a site free from FM radio interference.

Research by an international team including astronomers at the International Centre of Radio Astronomy Research (ICRAR) observing the region at the lowest-ever radio frequencies has helped fine-tune our understanding of stellar explosions.

The research paints a picture of the star's life long before its death in what was the closest and brightest supernova seen from Earth, now known as supernova remnant 1987A, which collapsed spectacularly almost 30 years ago.

Much had been known about the immediate past of this star through studying the cosmic ruins resulting from the star's collapse in 1987, which occurred in neighbouring galaxy, the Large Magellanic Cloud. However it was the detection of the very faintest of hisses through low-frequency radio astronomy that has provided the latest insights.

Previously, only the final fraction of the dead star's multi-million-year-long life, about 0.1% or 20,000 years, had been observable.

This latest research -- which has enabled astrophysicists to probe the supernova's past life millions of years further back than was previously possible -- was led by Joseph Callingham, a PhD candidate with the University of Sydney and the ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO).

The findings are published today in the Monthly Notices of the Royal Astronomical Society, Oxford University Press.

Operating the Murchison Widefield Array in the West Australian desert, the radio astronomers were able to 'see' right back to when the star was in its long-lasting red supergiant phase. Mr Callingham explained previous studies focused on material that was ejected into space when the star was in its final blue supergiant phase.

"Just like excavating and studying ancient ruins that teach us about the life of a past civilisation, my colleagues and I have used low-frequency radio observations as a window into the star's life," Mr Callingham said.

The star's secret past and deadly explosion are depicted in a video compiled by CAASTRO.

The team of researchers found the red supergiant lost its matter at a slower rate and generated slower winds that pushed into its surrounding environment than was previously assumed.

"Our new data improves our knowledge of the composition of space in the region of supernova 1987A; we can now go back to our simulations and tweak them, to better reconstruct the physics of supernovae," Mr Callingham said.

Professor Lister Staveley-Smith, co-author of this study and Deputy Director of CAASTRO and ICRAR, explained that the Murchison Radio-astronomy Observatory is one of the most radio quiet places on the planet and has enabled these sensitive observations to be made.

Read more at Science Daily

Still changing after all these years

Richard Lenski is MSU's Hannah Professor of Microbiology and Molecular Genetics. Science magazine called him "the man who bottled evolution."
If Paul Simon were to write a song about the bacteria in Richard Lenski's long-term evolution experiment, or LTEE, it could be titled, "Still Changing After All These Years."

In a paper published in the current issue of Nature, the Michigan State University John Hannah Distinguished Professor of Microbiology and Molecular Genetics and an international team of researchers used cutting-edge technology to study tens of thousands of generations of E. coli bacteria. They sequenced the entire genomes, or genetic code, of the bacteria to pinpoint the genes with beneficial mutations that gave the bacteria a competitive edge over their ancestors.

The bacteria from different generations of the LTEE have been stored in freezers for nearly 30 years, but they were brought back to life to look for the changes in their DNA. Being able to go back into the freezer to study samples from years ago is one of the reasons Lenski calls the LTEE "the experiment that keeps on giving."

"One of the nice things about such a long-term experiment is that new technologies come along that didn't exist when I started the LTEE in 1988," said Lenski, who's part of MSU's BEACON Center for the Study of Evolution in Action. "The first bacterial genome was not sequenced until 1995, and now, in this single paper, we've sequenced 264 complete genomes from this one experiment."

The team sequenced hundreds of E. coli genomes to examine how the bacteria had changed in their DNA over 50,000 generations. The researchers found more than 14,000 changes across the LTEE's 12 populations. Each population changed in different ways, but there were some important commonalities as well.

Most significant, and most simply, the mutations were concentrated in a subset of the genes -- those where mutations gave the bacteria a competitive edge. One of the striking differences that arose between populations is that half of them evolved to mutate at much higher rates than the other populations, even though they all started from the same ancestral strain that had a low mutation rate.

"Even in the simplest microcosm we can imagine to study evolution -- a single bacterium kept in the laboratory under monotonous conditions for years -- we are learning new things about the rates and processes of evolution," said Jeffrey Barrick, an assistant professor of molecular biosciences at the University of Texas at Austin. "This quantitative information is important for human health, as it improves our ability to predict how bacteria evolve, particularly in chronic infections and in our microbiome."

This paper is the product of several wonderful collaborations, Lenski said. Noah Ribeck, MSU postdoctoral researcher, developed some of the mathematical theory used to interpret the data. Barrick, a former MSU postdoc in Lenski's lab, created software for analyzing the genomes.

Read more at Science Daily

No, Asteroid Bennu Won't Destroy Earth

There is indeed a chance that the 1,650-foot-wide (500 meters) asteroid Bennu — the target of NASA's OSIRIS-REx spacecraft, which is scheduled to launch next month — could hit Earth late in the 22nd century.

But, mission officials stressed, that chance is slim, and the space rock is not nearly big enough to pose an existential threat to the planet, despite what some media reports claimed over the weekend.

"We're not talking about an asteroid that could destroy the Earth," OSIRIS-REx principal investigator Dante Lauretta, of the Lunar and Planetary Laboratory at the University of Arizona, told "We're not anywhere near that kind of energy for an impact."

Sampling an Asteroid

If all goes according to plan, the $800 million OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) mission will lift off atop a United Launch Alliance Atlas V rocket from Florida's Cape Canaveral Air Force Station on Sept. 8.

The spacecraft will spend two years chasing Bennu down, finally rendezvousing with the near-Earth asteroid in August 2018. OSIRIS-REx will then study the space rock from orbit for another two years before grabbing at least 2.1 ounces (60 grams) of surface material in July 2020.

In 2023, this relatively hefty sample should make it back to Earth, where researchers in laboratories around the globe will analyze the material in a number of ways.

The mission team is chiefly interested in learning the role that asteroids like Bennu — dark, primitive and apparently carbon-rich objects — may have played in helping life get a foothold on Earth, Lauretta said.

"Did these kinds of bodies deliver organic material and water, in the form of hydrated minerals like clays, to the surface of our planet that created the habitability and the environments that may have led to the origin of life?" Lauretta said.

"That's the prime mission," to investigate that question, he added.

There are secondary objectives as well, including learning more about the valuable resources that Bennu-like asteroids may harbor, Lauretta said. And then there's the planetary-defense angle, which has gotten a lot of attention in the last few days.

A Potentially Hazardous Asteroid

Bennu is officially classified as a potentially dangerous asteroid. In fact, there's an 0.037 percent (or 1-in-2,700) chance that it will strike Earth in the last quarter of the 22nd century, NASA scientists have calculated.

Specifically, that's the probability that, during an Earthy flyby in 2135, Bennu will hit a special orbit-altering "keyhole" that will send it on a collision course with the planet later in the century.

OSIRIS-REx will help scientists refine those odds, by refining their understanding of Bennu's orbit. (That orbit, by the way, is already the best-known of any asteroid, Lauretta said; thanks to extensive observations since Bennu's 1999 discovery, astronomers have nailed the space rock's orbital radius down to within 20 feet, or 6 m.)

"Our uncertainties will shrink, so that will allow us to recalculate the impact probability," Lauretta said. "We don't know which direction it'll go. It could go down, because we just eliminated a bunch of possible keyholes that Bennu may hit. Or it may go up, because in the area that's left we have a higher concentration of keyholes compared to the overall area of the uncertainty plane."

OSIRIS-REx's work will also help researchers better understand the Yarkovsky effect, which describes how absorbed sunlight, when radiated away as heat, affects an object's trajectory. Such information will improve knowledge not only of where Bennu is headed, but where it came from, Lauretta said.

But to focus on where it's headed — what if Bennu does hit one of those keyholes in 2135, and the space rock squares Earth up for an impact in 2185 or thereabouts? What should humanity expect?

Read more at Discovery News

Look Up! Perseid Meteors Could be Supercharged

The Perseids are here: The dazzling meteor shower's peak of activity is Aug. 12, but you can already see its streaks of light peppering the sky.

Skywatchers are particularly excited about this year's Perseids. Though the meteor shower is an annual event, the Perseids are in outburst this year. That means that rather than 80 meteors per hour, we might see 150 to 200 per hour, according to NASA meteor expert Bill Cooke.

"Next, we move into the August Perseids, which is perhaps the most popular meteor shower of all," Cooke told in our summer meteor shower guide. "This year, they will be in what we call 'outburst' — their rates will double, because we're running into more material left behind by Comet Swift-Tuttle." [Perseid Meteor Shower 2016: When & How to See It]

The Perseid meteor shower occurs when Earth moves through the trail of dust and debris left by Comet Swift-Tuttle as it orbits the sun; the debris hits Earth's atmosphere and burns up, creating the white-hot streaks we see in the sky. Most of the pieces of debris, which move at 37 miles per second (59 kilometers per second), are about the size of a grain of sand, NASA has said.

Earth is passing through a particularly dense clump of debris this year — the source of the outburst — caused by the influence of Jupiter's gravity on Swift-Tuttle's trail. The number of meteors is increasing as Earth penetrates the heart of the debris, and it will diminish again once it passes through (after the peak).

The moon will be full six days after the meteor shower's peak, which might wash out the vivid streaks across the sky. So it might be a good idea to look earlier on, before the peak, to see the brightest streaks and fireballs, and to go to the darkest location you can, Cooke said. All of the meteors will appear to stream away from the constellation Perseus — that apparent source is called the shower's radiant — but will materialize all across the sky.

You don't need a telescope to see the meteors. In fact, because telescopes narrow your field of view, it's much easier to watch a meteor shower with the naked eye, just looking up at the entire sky. It will take around 30 minutes in the dark night for your eyes to adjust, and Cooke suggested to plan for a few hours outdoors, taking in the views. The Perseids will appear most clearly in the Northern Hemisphere after 10 p.m. local time, and the meteor rate will increase each night all the way until dawn.

Read more at Discovery News

Aug 1, 2016

Origins of the female orgasm explained

Female orgasm seems to be a happy afterthought of our evolutionary past when it helped stimulate ovulation, a new study of mammals shows.

The role of female orgasm, which plays no obvious role in human reproduction, has intrigued scholars as far back as Aristotle. Numerous theories have tried to explain the origins of the trait, but most have concentrated on its role in human and primate biology.

Now scientists at Yale and the Cincinnati Children's Hospital have provided fresh insights on the subject by examining the evolving trait across different species. Their study appears Aug. 1 in the journal JEZ-Molecular and Developmental Evolution.

"Prior studies have tended to focus on evidence from human biology and the modification of a trait rather than its evolutionary origin," said Gunter Wagner, the Alison Richard Professor of Ecology and Evolutionary biology, and a member of Yale's Systems Biology Institute.

Instead, Wagner and Mihaela Pavličev of the Center for Prevention of Preterm Birth at Cincinnati Children's Hospital propose that the trait that evolved into human female orgasm had an ancestral function in inducing ovulation.

Since there is no apparent association between orgasm and number of offspring or successful reproduction in humans, the scientists focused on a specific physiological trait that accompanies human female orgasm -- the neuro-endocrine discharge of prolactin and oxytocin -- and looked for this activity in other placental mammals. They found that in many mammals this reflex plays a role in ovulation.

In spite of the enormous diversity of mammalian reproductive biology, some core characteristics can be traced throughout mammalian evolution, note the researchers. The female ovarian cycle in humans, for instance, is not dependent upon sexual activity. However, in other mammalian species ovulation is induced by males. The scientists' analysis shows male-induced ovulation evolved first and that cyclical or spontaneous ovulation is a derived trait that evolved later.

The scientists suggest that female orgasm may have evolved as an adaptation for a direct reproductive role -- the reflex that, ancestrally, induced ovulation. This reflex became superfluous for reproduction later in evolution, freeing female orgasm for secondary roles.

A comparative study of female genitalia also revealed that, coincidental with the evolution of spontaneous ovulation, the clitoris was relocated from its ancestral position inside the copulatory canal. This anatomical change made it less likely that the clitoris receives adequate stimulation during intercourse to lead to the neuro-endocrine reflex known in humans as orgasm.

Read more at Science Daily

New areas of the brain identified where ALS gene is active

The dentate gyrus of the mouse hippocampal formation which contributes to the formation of new episodic memories stained for neurons (green) and stem cells (red).
For the first time novel expression sites in the brain have been identified for a gene which is associated with Motor Neuron Disease and Frontotemporal Dementia.

Many people who develop Motor Neuron Disease, also called Amyotropic Lateral Sclerosis (ALS), and/or Frontotemporal Dementia (FTD) have abnormal repeats of nucleotides within a gene called C9orf72 which causes neurons to die.

A team from the Department of Biology & Biochemistry at the University of Bath discovered for the first time that the C9orf72 gene is strongly expressed in the hippocampus of the mouse brain- a region where adult stem cells reside and which is known to be important for memory.

C9orf72 is also expressed at the olfactory bulb, involved in the sense of smell. Loss of smell is sometimes a symptom in FTD.

They also found that the C9orf72 protein changes from being concentrated in the cytoplasm of cells to both the cytoplasm and nucleus as the brain cortex develops, and during the development of neurons.

Dr Vasanta Subramanian, who led the study, said: "By uncovering novel sites of expression in the brain our findings provide an important resource for researchers studying animal models of C9orf72 mediated ALS and FTD.

"It is essential to know in which cell types in the nervous system the C9orf72 gene is expressed and where within the cell the C9orf72 protein is present.

"Our hope is that by researching accurate animal models of these diseases scientists can eventually develop new treatments and eventually cures for these devastating degenerative diseases."

The researchers, Ross Ferguson, Eleni Serafeimidou- Pouliou and Vasanta Subramanian, were working to map expression of C9orf72 in developing and adult mouse brains to help characterise reliable animal models to study the gene and its effects in both kinds of neurodegenerative diseases, for which there are currently no cures.

Dr Brian Dickie, Director of Research Development at the Motor Neurone Disease Association, said: "It is unclear why people who carry an abnormality in genes like c9orf72 don't usually develop symptoms of these diseases until several decades after birth, but it is possible that the activity of the gene early in life somehow 'primes' certain types of neuron to degenerate later in life.

"This detailed study provides a platform for future research to understand the role of this important gene in health and disease."

Read more at Science Daily

Scientists grow mini human brains

A midbrain organoid in a petri dish. The black pigment is neuromelanin, a hallmark of the human midbrain.
Scientists in Singapore have made a big leap on research on the 'mini-brain'. These advanced mini versions of the human midbrain will help researchers develop treatments and conduct other studies into Parkinson's Disease (PD) and aging-related brain diseases.

These mini midbrain versions are three-dimensional miniature tissues that are grown in the laboratory and they have certain properties of specific parts of the human brains. This is the first time that the black pigment neuromelanin has been detected in an organoid model. The study also revealed functionally active dopaminergic neurons.

The human midbrain, which is the information superhighway, controls auditory, eye movements, vision and body movements. It contains special dopaminergic neurons that produce dopamine -- which carries out significant roles in executive functions, motor control, motivation, reinforcement, and reward. High levels of dopamine elevate motor activity and impulsive behaviour, whereas low levels of dopamine lead to slowed reactions and disorders like PD, which is characterised by stiffness and difficulties in initiating movements.

Also causing PD is the dramatic reduction in neuromelanin production, leading to the degenerative condition of patients, which includes tremors and impaired motor skills. This creation is a key breakthrough for studies in PD, which affects an estimated seven to 10 million people worldwide. Furthermore, there are people who are affected by other causes of parkinsonism. Researchers now have access to the material that is affected in the disease itself, and different types of studies can be conducted in the laboratory instead of through simulations or on animals. Using stem cells, scientists have grown pieces of tissue, known as brain organoids, measuring about 2 to 3 mm long. These organoids contain the necessary hallmarks of the human midbrain, which are dopaminergic neurons and neuromelanin.

Jointly led by Prof Ng Huck Hui from A*STAR's Genome Institute of Singapore (GIS) and Assistant Prof Shawn Je from Duke-NUS Medical School, this collaborative research between GIS, Duke-NUS, and the National Neuroscience Institute (NNI) is funded by the National Medical Research Council's Translational Clinical Research (TCR) Programme In Parkinson's disease (PD) and A*STAR. Other collaborators are from the Lieber Institute for Brain Development, the Johns Hopkins University School of Medicine, and the Nanyang Technological University.

Assistant Prof Shawn Je from Duke-NUS Medical School's Neuroscience & Behavioural Disorders Programme said, "It is remarkable that our midbrain organoids mimic human midbrain development. The cells divide, cluster together in layers, and become electrically and chemically active in three-dimensional environment like our brain. Now we can really test how these mini brains react to existing or newly developed drugs before treating patients, which will be a game changer for drug development."

Prof Tan Eng King, Research Director and Senior Consultant, Department of Neurology at NNI and Lead PI of the TCR Programme in PD, remarked, "The human brain is arguably the most complex organ and chronic brain diseases pose considerable challenges to doctors and patients. This achievement by our Singapore team represents an initial but momentous scientific landmark as we continue to strive for better therapies for our patients."

Read more at Science Daily

Is Earthly life premature from a cosmic perspective?

This artist's conception shows a red dwarf star orbited by a pair of habitable planets. Because red dwarf stars live so long, the probability of cosmic life grows over time. As a result, Earthly life might be considered "premature."
The universe is 13.8 billion years old, while our planet formed just 4.5 billion years ago. Some scientists think this time gap means that life on other planets could be billions of years older than ours. However, new theoretical work suggests that present-day life is actually premature from a cosmic perspective.

"If you ask, 'When is life most likely to emerge?' you might naively say, 'Now,'" says lead author Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. "But we find that the chance of life grows much higher in the distant future."

Life as we know it first became possible about 30 million years after the Big Bang, when the first stars seeded the cosmos with the necessary elements like carbon and oxygen. Life will end 10 trillion years from now when the last stars fade away and die. Loeb and his colleagues considered the relative likelihood of life between those two boundaries.

The dominant factor proved to be the lifetimes of stars. The higher a star's mass, the shorter its lifetime. Stars larger than about three times the sun's mass will expire before life has a chance to evolve.

Conversely, the smallest stars weigh less than 10 percent as much as the Sun. They will glow for 10 trillion years, giving life ample time to emerge on any planets they host. As a result, the probability of life grows over time. In fact, chances of life are 1000 times higher in the distant future than now.

"So then you may ask, why aren't we living in the future next to a low-mass star?" says Loeb.

"One possibility is we're premature. Another possibility is that the environment around a low-mass star is hazardous to life."

Although low-mass, red dwarf stars live for a long time, they also pose unique threats. In their youth they emit strong flares and ultraviolet radiation that could strip the atmosphere from any rocky world in the habitable zone.

To determine which possibility is correct -- our premature existence or the hazard of low-mass stars -- Loeb recommends studying nearby red dwarf stars and their planets for signs of habitability. Future space missions like the Transiting Exoplanet Survey Satellite and James Webb Space Telescope should help to answer these questions.

From Science Daily

Lack of Water Doomed Alaska Island Woolly Mammoths

About 5,600 years ago, on what is now Alaska's St. Paul Island, an isolated population of woolly mammoths gradually disappeared, and now scientists think they know why.

Decreased water levels in the island's lakes, along with decreased quality of the water likely doomed the mammoths, according to a new study by University of Alaska Fairbanks researchers.

"Freshwater resources look like the smoking gun for what pushed them into this untenable situation," said study co-author Matthew Wooller, in a statement.

Woolly mammoths became isolated on the island after the Bering Sea land bridge was covered by water during a period of rising sea levels. The island gradually became smaller, hampering the mammoths' chances to find new places with ample water.

Wooller and his colleagues extracted core samples from the bed of a freshwater lake on St. Paul Island, testing the remains of aquatic insects preserved in the sediment. Key chemical signatures retained by the insect remains allowed the scientists to assess the lake's water level and quality before, during, and after the time of the mammoths.

The analysis of the core told the researchers that water abundance and quality had indeed both diminished.

Meanwhile, chemical analyses of mammoth bones and teeth indicated that the island had grown progressively drier in the run-up to the animals' die-off.

The drier conditions and decreased lake levels "paints a dire picture of the situation for these mammoths," said Wooller.

Woolly mammoths disappeared from mainland sites some 10,000 years ago. About the size of today's African elephants, the last among them died out about 4,000 years ago on Russia's Wrangel Island, north of Siberia in the Arctic Ocean, an island also cut off by the submerged Bering Sea land bridge.

The St. Paul Island mammoths would have enjoyed the vegetation of the time, which was much as it is today, Wooller said in 2014. There's no evidence humans occupied the land at the same time as the mammoths.

Wooller and his team have published their findings in the journal Proceedings of the National Academy of Sciences.

From Discovery News

Jul 31, 2016

Novel 'repair system' discovered in algae may yield new tools for biotechnology

This is a TEM image of the algae C. reinhardtii.
A new way of fixing inactive proteins has been discovered in an algae, which uses chloroplast extracts and light to release an interrupting sequence from a protein.

Research specialist Stephen Campbell and Professor David Stern at the Boyce Thompson Institute report the discovery in the July 29 issue of the Journal of Biological Chemistry. This repair system may have applications in agriculture and biotechnology because it could potentially be harnessed to enable proteins to become active only in the light.

Many proteins contain extra sequences, called insertions, that can disrupt their function. The current paper demonstrates that the algae Chlamydomonas reinhardtii has the necessary toolkit to repair proteins by removing these insertions.

Campbell discovered this new repair system while purifying a protein from the chloroplasts of C. reinhardtii that can cut RNA. Upon sequencing the protein, he identified it as RB47, a protein that was not known to have any RNA-cleaving ability. Campbell noticed that the middle of the protein was missing. When he compared the protein sequence to its corresponding gene sequence, the protein was much shorter than expected.

Upon further study, Campbell found that he could detect a long version of the protein that contained an insertion and a short version that didn't. The cells make both versions when grown in the light or the dark, but only the short version can cleave RNA. The long version of the protein could be converted into the short one by mixing it in a test tube with chloroplasts from cells grown in the light and by illuminating the reaction. This process removed the interrupting insertion and restored the RNA-cutting activity of the protein. It is likely that the chloroplast maintains the machinery necessary to remove the sequence so that it can restore functionality to the protein.

This new type of repair system provides intriguing possibilities for biotech applications.

Because the insertion can be placed so that it interrupts a protein's function, the insertion and repair system may be useful for producing certain pharmaceuticals or protein products -- such as cancer drugs -- in culture, which would otherwise kill the cell. After purification, the inactive products could be treated with chloroplast factors and light to remove the insertion and activate the proteins.

In future work, the researchers plan to investigate exactly how the insertion becomes spliced out of the protein and which plant factors facilitate its removal. They also aim to understand the purpose of the insertion, and whether the algae can control the splicing to respond to changes in the environment.

Read more at Science Daily

Chorus of black holes radiates X-rays

The blue dots in this field of galaxies, known as the COSMOS field, show galaxies that contain supermassive black holes emitting high-energy X-rays. They were detected by NASA's Nuclear Spectroscopic Array, or NuSTAR, which spotted 32 such black holes in this field and has observed hundreds across the whole sky so far. The other colored dots are galaxies that host black holes emitting lower-energy X-rays, and were spotted by NASA's Chandra X-ray Observatory. Chandra data show X-rays with energies between 0.5 to 7 kiloelectron volts, while NuSTAR data show X-rays between 8 to 24 kiloelectron volts.
Supermassive black holes do not give off any of their own light, hence the word "black" in their name. However, many black holes pull in, or accrete, surrounding material, and emit powerful bursts of X-rays. Collectively, these active black holes throughout the sky can be thought of a cosmic choir, singing in the language of X-rays. Their "song" is what astronomers call the cosmic X-ray background.

To date, NASA's Chandra mission has managed to pinpoint many of the individual black holes contributing to the X-ray background, but the ones that let out high-energy X-rays--those with the highest-pitched "voices"--have remained elusive.

New data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, has, for the first time, begun to pinpoint large numbers of the black holes sending out the high-energy X-rays. More technically, NuSTAR has made significant progress in resolving the high-energy X-ray background.

"We've gone from resolving just 2 percent of the high-energy X-ray background to 35 percent," says Fiona Harrison, Benjamin M. Rosen Professor of Physics and Astronomy at Caltech, the principal investigator of NuSTAR, and lead author of a new study describing the findings in an upcoming issue of The Astrophysical Journal. "We can see the most obscured black holes, hidden in thick gas and dust."

The results will ultimately help astronomers understand how the growth patterns of supermassive black holes change over time--a key factor in the development of black holes and the galaxies that host them. For instance, the supermassive black hole at the center of our Milky Way galaxy is dormant now, but at some point in the past, it would have siphoned gas and bulked up in size.

As black holes grow, their intense gravity pulls matter toward them. The matter heats up to extremely high temperatures and particles get boosted to close to the speed of light. Together, these processes make the black hole surroundings glow with X-rays. A supermassive black hole with an ample supply of fuel, or gas, will give off more high-energy X-rays.

NuSTAR is the first telescope capable of focusing these high-energy X-rays into sharp pictures.

"Before NuSTAR, the X-ray background in high-energies was just one blur with no resolved sources," says Harrison. "To untangle what's going on, you have to pinpoint and count up the individual sources of the X-rays."

"We knew this cosmic choir had a strong high-pitched component, but we still don't know if it comes from a lot of smaller, quiet singers, or a few with loud voices," says coauthor Daniel Stern, the project scientist for NuSTAR at JPL. "Now, thanks to NuSTAR, we're gaining a better understanding of the black holes and starting to address these questions."

High-energy X-rays can reveal what lies around the most obscured supermassive black holes, which are otherwise hard to see. In the same way that medical X-rays can travel through your skin to reveal pictures of bones, NuSTAR can see through the gas and dust around black holes, to get a deeper view of what is going on inside.

With NuSTAR's more complete picture of supermassive black hole populations, astronomers can begin to puzzle together how these objects evolve and change over time. When did they start and stop growing? What is the distribution of the gas and dust that both feed and hide the black holes?

The team expects that over time, NuSTAR will be able to resolve more of the high-energy X-ray background--and better decipher the X-ray song of the universe's black holes.

From Science Daily