Last of universe's missing ordinary matter

A simulation of the cosmic web, or diffuse tendrils of gas connecting galaxies across the universe.

Researchers at the University of Colorado Boulder have helped to find the last reservoir of ordinary matter hiding in the universe.

Ordinary matter, or "baryons," make up all physical objects in existence, from stars to the cores of black holes. But until now, astrophysicists had only been able to locate about two-thirds of the matter that theorists predict was created by the Big Bang.

In the new research, an international team pinned down the missing third, finding it in the space between galaxies. That lost matter exists as filaments of oxygen gas at temperatures of around 1 million degrees Celsius, said CU Boulder's Michael Shull, a co-author of the study.

The finding is a major step for astrophysics. "This is one of the key pillars of testing the Big Bang theory: figuring out the baryon census of hydrogen and helium and everything else in the periodic table," said Shull of the Department of Astrophysical and Planetary Sciences (APS).

The new study, which will appear June 20 in Nature, was led by Fabrizio Nicastro of the Italian Istituto Nazionale di Astrofisica (INAF) -- Osservatorio Astronomico di Roma and the Harvard-Smithsonian Center for Astrophysics.

Researchers have a good idea of where to find most of the ordinary matter in the universe -- not to be confused with dark matter, which scientists have yet to locate: About 10 percent sits in galaxies, and close to 60 percent is in the diffuse clouds of gas that lie between galaxies.

In 2012, Shull and his colleagues predicted that the missing 30 percent of baryons were likely in a web-like pattern in space called the warm-hot intergalactic medium (WHIM). Charles Danforth, a research associate in APS, contributed to those findings and is a co-author of the new study.

To search for missing atoms in that region between galaxies, the international team pointed a series of satellites at a quasar called 1ES 1553 -- a black hole at the center of a galaxy that is consuming and spitting out huge quantities of gas. "It's basically a really bright lighthouse out in space," Shull said.

Scientists can glean a lot of information by recording how the radiation from a quasar passes through space, a bit like a sailor seeing a lighthouse through fog. First, the researchers used the Cosmic Origins Spectrograph on the Hubble Space Telescope to get an idea of where they might find the missing baryons. Next, they homed in on those baryons using the European Space Agency's X-ray Multi-Mirror Mission (XMM-Newton) satellite.

The team found the signatures of a type of highly-ionized oxygen gas lying between the quasar and our solar system -- and at a high enough density to, when extrapolated to the entire universe, account for the last 30 percent of ordinary matter.

"We found the missing baryons," Shull said.

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Einstein proved right in another galaxy

The gravitational lens from LRG 3-757 galaxy taken with the Hubble Space Telescope's Wide Field Camera 3.

An international team of astronomers have made the most precise test of gravity outside our own solar system.

By combining data taken with NASA's Hubble Space Telescope and the European Southern Observatory's Very Large Telescope, the researchers show that gravity in this galaxy behaves as predicted by Albert Einstein's general theory of relativity, confirming the theory's validity on galactic scales.

In 1915 Albert Einstein proposed his general theory of relativity (GR) to explain how gravity works. Since then GR has passed a series of high precision tests within the solar system, but there have been no precise tests of GR on large astronomical scales.

It has been known since 1929 that the Universe is expanding, but in 1998 two teams of astronomers showed that the Universe is expanding faster now than it was in the past. This surprising discovery -- which won the Nobel Prize in 2011 -- cannot be explained unless the Universe is mostly made of an exotic component called dark energy. However, this interpretation relies on GR being the correct theory of gravity on cosmological scales. Testing the long distance properties of gravity is important to validate our cosmological model.

A team of astronomers, led by Dr Thomas Collett of the Institute of Cosmology and Gravitation at the University of Portsmouth, used a nearby galaxy as a gravitational lens to make a precise test of gravity on astronomical length scales.

Dr Collett said: "General Relativity predicts that massive objects deform space-time, this means that when light passes near another galaxy the light's path is deflected. If two galaxies are aligned along our line of sight this can give rise to a phenomenon, called strong gravitational lensing, where we see multiple images of the background galaxy. If we know the mass of the foreground galaxy, then the amount of separation between the multiple images tells us if General Relativity is the correct theory of gravity on galactic scales."

A few hundred strong gravitational lenses are known, but most are too distant to precisely measure their mass, so they can't be used to accurately test GR. However, the galaxy ESO325-G004 is amongst the closest lenses, at 500 million light years from Earth.

Dr Collett continues: "We used data from the Very Large Telescope in Chile to measure how fast the stars were moving in E325 -- this let us infer how much mass there must be in E325 to hold these stars in orbit. We then compared this mass to the strong lensing image separations that we observed with the Hubble Space telescope and the result was just what GR predicts with 9 per cent precision. This is the most precise extrasolar test of GR to date, from just one galaxy."

"The Universe is an amazing place providing such lenses which we can then use as our laboratories," adds team member Professor Bob Nichol, Director of the Institute of Cosmology and Gravitation. "It is so satisfying to use the best telescopes in the world to challenge Einstein, only to find out how right he was."

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Stone tools from ancient mummy reveal how Copper Age mountain people lived

This is a stone tool.

Stone tools found with a 5,300-year-old frozen mummy from Northern Italy reveal how alpine Copper Age communities lived, according to a study published June 20, 2018 in the open-access journal PLOS ONE by Ursula Wierer from the Soprintendenza Archeologia, Florence, Italy, and colleagues.

The Tyrolean Iceman is a mummified body of a 45-year-old man originally discovered with his clothes and personal belongings in a glacier of the Alps mountains, in the South Tyrol region, Italy. Previous research showed that the Iceman lived during the Copper Age, between 3370-3100 BC, and was probably killed by an arrow. In this study, the researchers analyzed the Iceman's chert tools to learn more about his life and the events that led to his tragic death.

The team used high-power microscopes and computed tomography to examine the chert tools in microscopic detail, including a dagger, borer, flake, antler retoucher, and arrowheads. The structure of the tools' chert reveals that the stone was collected from several different outcrops in what is now the Trentino region (Italy), about 70km away from where the Iceman was thought to live. Comparing this ancient toolkit with other Copper Age artefacts revealed stylistic influences from distant alpine cultures. By carefully analyzing the wear traces of the Iceman's chert tools, the authors concluded he was right-handed and probably had recently resharpened and reshaped some of his equipment.

These findings shed light into the Iceman's personal history and support previous evidence suggesting that alpine Copper Age communities maintained long-distance cultural contacts and were well provisioned with chert.

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Fossils show ancient primates had grooming claws as well as nails

Lemurs, lorises and galagoes have nails on most digits and grooming claws on their second toes, as seen on the feet of two greater slow lorises, Nycticebus coucang, in the Florida Museum mammals collection.

Humans and other primates are outliers among mammals for having nails instead of claws. But how, when and why we transitioned from claws to nails has been an evolutionary head-scratcher.

Now, new fossil evidence shows that ancient primates -- including one of the oldest known, Teilhardina brandti -- had specialized grooming claws as well as nails. The findings overturn the prevailing assumption that the earliest primates had nails on all their digits and suggest the transition from claws to nails was more complex than previously thought.

"We had just assumed nails all evolved once from a common ancestor, and in fact, it's much more complicated than that," said Jonathan Bloch, study co-author and Florida Museum of Natural History curator of vertebrate paleontology at the University of Florida.

The findings are scheduled to be published today in the Journal of Human Evolution.

Grooming in mammals is not just about looking good. Thick body hair is a haven for ticks, lice and other parasites -- possible health threats, as well as nuisances. Having a specialized claw for removing pests would be an evolutionary advantage, said Doug Boyer, an associate professor in the department of evolutionary anthropology at Duke University and the study's lead author.

It's one that has been retained in many primates. Lemurs, lorises, galagoes and tarsiers have nails on most of their digits and grooming claws on their second -- and in tarsiers, second and third -- toes.

So, why did the ancestors of monkeys, apes and humans lose their grooming claws? One possible answer: because we have each other.

"The loss of grooming claws is probably a reflection of more complex social networks and increased social grooming," Boyer said. "You're less reliant on yourself."

This could explain why more solitary monkey species, such as titi and owl monkeys, have re-evolved a grooming claw, he said.

Researchers had thought grooming claws likely developed independently several times along the lines that gave rise to living primates. But these fossils suggest grooming claws were hallmark features of the earliest primates, dating back at least 56 million years.

They also come from five different genera of ancient primates that belonged to the omomyoids, the ancestors of monkeys, apes, humans and tarsiers -- not the branch of primates that gave rise to lemurs, lorises and galagoes.

In 2013, Boyer was at the University of California Museum of Paleontology, sifting through sediment collected in Wyoming several decades earlier, when he found several curious primate fossils. They were distal phalanges, the bones at the tips of fingers and toes, from omomyoids. The shape of these bones reveals whether they support a claw or nail. Bones topped with a claw mimic its narrow, tapered structure while bones undergirding a nail are flat and wide. The distal phalanges that Boyer discovered looked like they belonged to animals with grooming claws.

"Prior to this study, no one knew whether omomyoids had grooming claws," Boyer said. "Most recent papers came down on the side of nails."

Meanwhile, Bloch, picking through collections recently recovered from Bighorn Basin, Wyoming, came across what looked like a "strange, narrow nail" bone. But when he compared it to modern primates, "it looked just like a tarsier grooming claw." Smaller than a grain of rice, it matched the proportions of Teilhardina brandti, a mouse-sized, tree-dwelling primate.

Bloch and Boyer had co-authored a 2011 study describing the first fossil evidence of nails in Teilhardina. At the time, they believed the primate had nails on all its digits. Now, fossils were making them reevaluate their assumptions, not only about Teilhardina, but other omomyoids.

On the off-chance that they could add one more ancient primate to the growing list of claw-bearers, the pair drove out to Omomys Quarry, Wyoming, once inhabited by another genus of omomyoid, Omomys.

"We spent a day combing that site, never expecting to find something as tiny and delicate as a grooming claw," Boyer said.

The team picked one right off the surface. They had found grooming claws at three independent sites from omomyoids spanning about 10 million years in the fossil record.

"That was the last nail in the coffin," Boyer said.

Why did primates develop nails at all? The question is a contentious one, but Bloch and Boyer think the transition away from claws could have mirrored changes in primate movement. As we ramped up climbing, leaping and grasping, nails might have proven more practical than claws, which could snag or get in the way.

Grooming claws might seem insignificant, but they can provide crucial insights into ancient primates, many of which are known only from fossil teeth, Bloch said. These tiny claws offer clues about how our earliest ancestors moved through their environment, whether they were social or solitary and what their daily behavior was like.

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How do horses read human emotional cues?

Several horses on a farm visited by Dr. Ayaka Takimoto.

Scientists demonstrated for the first time that horses integrate human facial expressions and voice tones to perceive human emotion, regardless of whether the person is familiar or not.

Recent studies showed the herd-forming animal possesses high communication capabilities, and can read the emotions of their peers through facial expressions and contact calls, or whinnies. Horses have long been used as a working animal and also as a companion animal in sports and leisure, establishing close relationships with humans just like dogs do with people.

Dogs are known to relate human facial expressions and voices to perceive human emotions, but little has been known as to whether horses can do the same.

In the present study to be published in Scientific Reports, Associate Professor Ayaka Takimoto of Hokkaido University, graduate student Kosuke Nakamura of The University of Tokyo, and former Professor Toshikazu Hasegawa of The University of Tokyo, used the expectancy violation method to investigate whether horses cross-modally perceive human emotion by integrating facial expression and voice tone. They also tested whether the familiarity between the horse and the person affected the horse's perception.

The expectancy violation method has been used to study infant cognitive development. Horses were shown a picture of a happy facial expression or an angry facial expression on a screen, and they then heard a pre-recorded human voice -- praising or scolding -- from a speaker behind the screen. Horses received both the congruent condition, in which the emotional values of facial expression and voice tone were matched, and the incongruent condition, in which they were not.

Results of the experiment showed that horses responded to voices 1.6 to 2.0 times faster in the incongruent condition than in the congruent condition regardless of familiarity of the person. In addition, the horses looked to the speaker 1.4 times longer in the incongruent condition than in the congruent condition when the person was familiar. These results suggest that horses integrate human facial expressions and voice tones to perceive human emotions, therefore an expectancy violation occurred when horses heard a human voice whose emotional value was not congruent with the human facial expression.

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The seed that could bring clean water to millions

(left) Unshelled M. oleifera seeds, (middle) shelled seeds, (right) crushed seeds before protein extraction.

According to the United Nations, 2.1 billion people lack access to safely managed drinking water services, the majority of whom live in developing nations.

Carnegie Mellon University's Biomedical Engineering and Chemical Engineering Professors Bob Tilton and Todd Przybycien recently co-authored a paper with Ph.D. students Brittany Nordmark and Toni Bechtel, and alumnus John Riley, further refining a process that could soon help provide clean water to many in water-scarce regions. The process, created by Tilton's former student and co-author Stephanie Velegol, uses sand and plant materials readily available in many developing nations to create a cheap and effective water filtration medium, termed "f-sand."

"F-sand" uses proteins from the Moringa oleifera plant, a tree native to India that grows well in tropical and subtropical climates. The tree is cultivated for food and natural oils, and the seeds are already used for a type of rudimentary water purification. However, this traditional means of purification leaves behind high amounts of dissolved organic carbon (DOC) from the seeds, allowing bacteria to regrow after just 24 hours. This leaves only a short window in which the water is drinkable.

Velegol, who is now a professor of chemical engineering at Penn State University, had the idea to combine this method of water purification with sand filtration methods common in developing areas. By extracting the seed proteins and adsorbing (adhering) them to the surface of silica particles, the principal component of sand, she created f-sand. F-sand both kills microorganisms and reduces turbidity, adhering to particulate and organic matter. These undesirable contaminants and DOC can then be washed out, leaving the water clean for longer, and the f-sand ready for reuse.

While the basic process was proven and effective, there were still many questions surrounding f-sand's creation and use -- questions Tilton and Przybycien resolved to answer.

Would isolating certain proteins from the M. oleifera seeds increase f-sand's effectiveness? Are the fatty acids and oils found in the seeds important to the adsorption process? What effect would water conditions have? What concentration of proteins is necessary to create an effective product?

The answers to these questions could have big implications on the future of f-sand.

Fractionation

The seed of M. oleifera contains at least eight different proteins. Separating these proteins, a process known as fractionation, would introduce another step to the process. Prior to their research, the authors theorized that isolating certain proteins might provide a more efficient finished product.

However, through the course of testing, Tilton and Przybycien found that this was not the case. Fractionating the proteins had little discernible effect on the proteins' ability to adsorb to the silica particles, meaning this step was unnecessary to the f-sand creation process.

The finding that fractionation is unnecessary is particularly advantageous to the resource-scarce scenario in which f-sand is intended to be utilized. Leaving this step out of the process helps cut costs, lower processing requirements, and simplify the overall process.

Fatty Acids

One of the major reasons M. oleifera is cultivated currently is for the fatty acids and oils found in the seeds. These are extracted and sold commercially. Tilton and Przybycien were interested to know if these fatty acids had an effect on the protein adsorption process as well.

They found that much like fractionation, removing the fatty acids had little effect on the ability of the proteins to adsorb. This finding also has beneficial implications for those wishing to implement this process in developing regions. Since the presence or absence of fatty acids in the seeds has little effect on the creation or function of f-sand, people in the region can remove and sell the commercially valuable oil, and still be able to extract the proteins from the remaining seeds for water filtration.

Concentration

Another parameter of the f-sand manufacturing process that Tilton and Przybycien tested was the concentration of seed proteins needed to create an effective product. The necessary concentration has a major impact on the amount of seeds required, which in turn has a direct effect on overall efficiency and cost effectiveness.

The key to achieving the proper concentration is ensuring that there are enough positively charged proteins to overcome the negative charge of the silica particles to which they are attached, creating a net positive charge. This positive charge is crucial to attract the negatively charged organic matter, particulates, and microbes contaminating the water.

This relates to another potential improvement to drinking water treatment investigated by Tilton, Przybycien, and Nordmark in a separate publication. In this project, they used seed proteins to coagulate contaminants in the water prior to f-sand filtration. This also relies on controlling the charge of the contaminants, which coagulate when they are neutralized. Applying too much protein can over-charge the contaminants and inhibit coagulation.

"There's kind of a sweet spot in the middle," says Tilton, "and it lies in the details of how the different proteins in these seed protein mixtures compete with each other for adsorption to the surface, which tended to broaden that sweet spot."

This broad range of concentrations means that not only can water treatment processes be created at relatively low concentrations, thereby conserving materials, but that there is little risk of accidentally causing water contamination by overshooting the concentration. In areas where exact measurements may be difficult to make, this is crucial.

Water Hardness

Water hardness refers to the amount of dissolved minerals in the water. Although labs often use deionized water, in a process meant to be applied across a range of real world environments, researchers have to prepare for both soft and hard water conditions.

Tilton and Przybycien found that proteins were able to adsorb well to the silica particles, and to coagulate suspended contaminants, in both soft and hard water conditions. This means that the process could potentially be viable across a wide array of regions, regardless of water hardness.

Tilton and Przybycien recently published a paper on this research, "Moringa oleifera Seed Protein Adsorption to Silica: Effects of Water Hardness, Fractionation, and Fatty Acid Extraction," in ACS Langmuir.

Overall, the conclusions that Tilton, Przybycien, and their fellow authors were able to reach have major benefits for those in developing countries looking for a cheap and easily accessible form of water purification. Their work puts this novel innovation one step closer to the field, helping to forge the path that may one day see f-sand deployed in communities across the developing world. They've shown that the f-sand manufacturing process displays a high degree of flexibility, as it is able to work at a range of water conditions and protein concentrations without requiring the presence of fatty acids or a need for fractionation.

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Nearly 80 exoplanet candidates identified in record time

NASA’s Kepler Space Telescope orbits the Sun in concert with the Earth, slowly drifting away from Earth.

Scientists at MIT and elsewhere have analyzed data from K2, the follow-up mission to NASA's Kepler Space Telescope, and have discovered a trove of possible exoplanets amid some 50,000 stars.

In a paper that appears online today in The Astronomical Journal, the scientists report the discovery of nearly 80 new planetary candidates, including a particular standout: a likely planet that orbits the star HD 73344, which would be the brightest planet host ever discovered by the K2 mission.

The planet appears to orbit HD 73344 every 15 days, and based on the amount of light that it blocks each time it passes in front of its star, scientists estimate that the planet is about 2.5 times the size of the Earth and 10 times as massive. It is also likely incredibly hot, with a temperature somewhere in the range of 1,200 to 1,300 degrees Celsius, or around 2,000 degrees Fahrenheit -- about the temperature of lava from an erupting volcano.

The planet lies at a relatively close distance of 35 parsecs, or about 114 light years from Earth. Given its proximity and the fact that it orbits a very bright star, scientists believe the planet is an ideal candidate for follow-up studies to determine its atmospheric composition and other characteristics.

"We think it would probably be more like a smaller, hotter version of Uranus or Neptune," says Ian Crossfield, an assistant professor of physics at MIT who co-led the study with graduate student Liang Yu.

The new analysis is also noteworthy for the speed with which it was performed. The researchers were able to use existing tools developed at MIT to rapidly search through graphs of light intensity called "lightcurves" from each of the 50,000 stars that K2 monitored in its two recent observing campaigns. They quickly identified the planetary candidates and released the information to the astronomy community just weeks after the K2 mission made the spacecraft's raw data available. A typical analysis of this kind takes between several months and a year.

Crossfield says such a fast planet-search enables astronomers to follow up with ground-based telescopes much sooner than they otherwise would, giving them a chance to catch a glimpse of planetary candidates before the Earth passes by that particular patch of sky on its way around the sun.

Such speed will also be a necessity when scientists start receiving data from NASA's Transiting Exoplanet Survey Satellite, TESS, which is designed to monitor nearby stars in 30-day swaths and will ultimately cover nearly the entire sky.

"When the TESS data come down, there'll be a few months before all of the stars that TESS looked at for that month 'set' for the year," Crossfield says. "If we get candidates out quickly to the community, everyone can start immediately observing systems discovered by TESS, and doing a lot of great planetary science. So this [analysis] was really a dress rehearsal for TESS."

Speed dips

The team analyzed data from K2's 16th and 17th observing campaigns, known as C16 and C17. During each campaign, K2 observes one patch of the sky for 80 days. The telescope is on an orbit that trails the Earth as it travels around the sun. For most other campaigns, K2 has been in a "rear-facing" orientation, in which the telescope observes those stars that are essentially in its rear-view mirror.

Since the telescope travels behind the Earth, those stars that it observes are typically not observable by scientists until the planet circles back around the sun to that particular patch of sky, nearly a year later. Thus, for rear-facing campaigns, Crossfield says there has been little motivation to analyze K2 data quickly.

The C16 and C17 campaigns, on the other hand, were forward-facing; K2 observed those stars that were in front of the telescope and within Earth's field of view, at least for the next several months. Crossfield, Yu, and their colleagues took this as an opportunity to speed up the usual analysis of K2 data, to give astronomers a chance to quickly observe planetary candidates before the Earth passed them by.

During C16, K2 observed 20,647 stars over 80 days, between Dec. 7, 2017, and Feb. 25, 2018. On Feb. 28, the mission released the data, in the form of pixel-level images, to the astronomy community. Yu and Crossfield immediately began to sift through the data, using algorithms developed at MIT to winnow down the field from 20,000-some stars to 1,000 stars of interest.

The team then worked around the clock, looking through these 1,000 stars by eye for signs of transits, or periodic dips in starlight that could signal a passing planet. In the end, they discovered 30 "highest-quality" planet candidates, whose periodic signatures are especially likely to be caused by transiting planets.

"Our experience with four years of K2 data leads us to believe that most of these are indeed real planets, ready to be confirmed or statistically validated," the researchers write in their paper.

They also identified a similar number of planet candidates in the recent C17 analysis. In addition to these planetary candidates, the group also picked out hundreds of periodic signals that could be signatures of astrophysical phenomena, such as pulsating or rotating stars, and at least one supernova in another galaxy.

Stars in spades

While the nature of a star doesn't typically change over the course of a year, Crossfield says the sooner researchers can follow up on a possible planetary transit, the better chance there is of confirming that a planet actually exists.

"You want to observe [candidates] again relatively soon so you don't lose the transit altogether," Crossfield says. "You might be able to say, 'I know there's a planet around that star, but I'm no longer at all certain when the transits will happen.' That's another motivation for following these things up more quickly."

Since the team released its results, astronomers have validated four of the candidates as definite exoplanets. They have been observing other candidates that the study identified, including the possible planet orbiting HD 73344. Crossfield says the brightness of this star, combined with the speed with which its planetary candidate was identified, can help astronomers quickly zero in on even more specific features of this system.

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Swedes have been brewing beer since the Iron Age, new evidence confirms

Carbonized germinated grains found at Uppåkra, Sweden.

Archaeologists at Lund University in Sweden have found carbonised germinated grains showing that malt was produced for beer brewing as early as the Iron Age in the Nordic region. The findings made in Uppåkra in southern Sweden indicate a large-scale production of beer, possibly for feasting and trade.

"We found carbonised malt in an area with low-temperature ovens located in a separate part of the settlement. The findings are from the 400-600s, making them one of the earliest evidence of beer brewing in Sweden," says Mikael Larsson, who specialises in archaeobotany, the archaeology of human-plant interactions.

Archaeologists have long known that beer was an important product in ancient societies in many parts of the world. Through legal documents and images, it has been found, for example, that beer was produced in Mesopotamia as early as 4 000 BCE. However, as written sources in the Nordic region are absent prior to the Middle Ages (before ca 1200 CE), knowledge of earlier beer production is dependent on botanical evidence.

"We often find cereal grains on archaeological sites, but very rarely from contexts that testify as to how they were processed. These germinated grains found around a low-temperature oven indicate that they were used to become malt for brewing beer," says Mikael Larsson.

Beer is made in two stages. The first is the malting process, followed by the actual brewing. The process of malting starts by wetting the grain with water, allowing the grain to germinate. During germination, enzymatic activities starts to convert both proteins and starches of the grain into fermentable sugars. Once enough sugar has been formed, the germinated grain is dried in an oven with hot air, arresting the germination process. This is what happened in the oven in Uppåkra.

"Because the investigated oven and carbonised grain was situated in an area on the site with several similar ovens, but absent of remains to indicate a living quarter, it is likely that large-scale production of malt was allocated to a specific area on the settlement, intended for feasting and/or trading," explains Mikael Larsson.

Early traces of malt in connection with beer brewing have only been discovered in two other places in the Nordic region. One is in Denmark from 100 CE and one is in Eketorp on Öland from around 500 CE.

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Beluga whales have sensitive hearing, little age-related loss

Beluga whales have small external ear openings, located a few inches behind each eye. All work conducted under NMFS permit no. 14245.

Scientists published the first hearing tests on a wild population of healthy marine mammals. The tests on beluga whales in Bristol Bay, Alaska, revealed that the whales have sensitive hearing abilities and the number of animals that experienced extensive hearing losses was far less than what scientists had anticipated.

The latter findings contrasted with expectations from previous studies of humans and bottlenose dolphins, which showed more hearing loss as they aged, says Aran Mooney, a biologist at Woods Hole Oceanographic Institution (WHOI) and lead author of two new studies on beluga whales. "But unlike the wild beluga population, the dolphins that were studied lived in a very noisy environment, as most humans do."

At a time when noise in the ocean is increasing from human activities, such as oil and gas exploration and ship traffic, understanding the natural hearing abilities of whales and other endangered marine mammals is crucial to assessing potential noise impacts on animals and to management efforts to mitigate sound-induced hearing loss.

In the two related studies, WHOI researchers and their colleagues measured the hearing sensitivity of 26 wild belugas and then compared the audiograms to acoustic measurements made within their summer habitat in Bristol Bay to study how natural soundscapes-all sounds within their environment-may influence hearing sensitivity. The soundscape also reveals sound clues that the belugas may use to navigate. The first study was published May 8, 2018, in the Journal of Experimental Biology. Results from the soundscape study were published June 20, 2018, in the Journal of Ecoacoustics. "In the first paper, we characterized the beluga population's hearing ability, which had not been done before in a healthy, wild population," says Mooney. "And in the second paper, we put that into context to see how they might use acoustic differences in their habitat and how their hearing is influenced by the natural ambient noise in their environment."

How do you test a beluga whale's hearing? Researchers applied the same screening method that doctors use to test the hearing of newborn babies who can't yet vocally respond to whether or not they hear sounds: automated auditory brainstem response.

A suction cup sensor is gently placed on the whales' head, just behind the blowhole, and another is placed on the back for reference. A series of quiet tones are played, and the sensors help measure the brain's response to the sounds from the surface of the skin.

"It's fairly straightforward," Mooney says. "We just had to make a portable system that we could bring out into an extreme environment in order to perform the hearing tests."

The test itself goes quickly, taking only about five minutes to measure each frequency. The most challenging part, says Mooney, is catching the participants.

For that, the researchers relied on the expertise of Alaskan Natives who hunt belugas. From small aluminum boats, the team would approach an individual adult whale-no calves were included in the study-in shallow waters of the bay. Taking care not to stress or injure the whale, they would catch it in a soft net. Marine mammal handlers, including teams from Georgia Aquarium, Shedd Aquarium, and Mystic Aquarium, would then get in the water to help secure the animal's tail with a rope before moving it to a belly band (like a small stretcher) in the water next to a soft inflatable boat where the hearing tests took place.

"The belugas stayed relatively relaxed during the tests, seemingly employing a resting behavior that they may use to avoid killer whales," Mooney explains. "When a killer whale is hunting them, belugas will often move to very shallow water and quietly stay there until they can safely return to deeper waters."

In addition to the auditory testing, the researchers also performed a physical exam to assess the overall health, sex, and estimated age of each animal and obtained skin, breath, and blood samples to collect information on the whales' hormone levels, microbiome bacteria, and other health-related data. The assessments were part of a beluga population health assessment program coordinated by the NOAA Fisheries Alaska Fisheries Science Center, the Alaska Department of Fish and Game, and Alaska SeaLife Center. Satellite transmitters were attached to some of the whales before release to study the whales' movements.

The hearing tests revealed little hearing loss in the seemingly older members of the population, which could be because the estuary where the belugas reside is fairly quiet compared to more urban areas.

"Because there haven't been any other studies of the hearing of wild marine mammals, we compared the results to previous studies of captive dolphins in San Diego and in Russia," Mooney says. "The dolphins showed clear hearing loss as they aged, but the San Diego group lives in a very noisy environment, as most humans do."

Mooney and colleagues also compared the wild belugas tests to those of belugas living in human care facilities. Both groups heard similarly well, and the authors suggest that it is likely due to the quiet environments in which they live.

"Sensitive hearing within a quiet soundscape could allow belugas to detect predators, navigate, and communicate with their young via low-amplitude signals," Mooney explains. "This hearing sensitivity could be compromised in a noisier environment. It also suggests management concerns for animals that inhabit noisy areas, where they may already be showing greater proportions of hearing loss."

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Birds have time-honored traditions, too

By faithfully copying the most popular songs, swamp sparrows create time-honored song traditions that can be just as long-lasting as human traditions, researchers report.

What makes human cultural traditions unique? One common answer is that we are better copycats than other species, which allows us to pass our habits and ways of life down through the generations without losing or forgetting them.

But a new study of birdsong finds that swamp sparrows are good impersonators too. And by faithfully copying the most popular songs, these birds create time-honored song traditions that can be just as long-lasting as human traditions, researchers say.

In fact, swamp sparrow song traditions often last hundreds of years, with some songs going back further than that.

"According to the models, some of the songs could go back as far as the Vikings," said first author Robert Lachlan, a lecturer in psychology at Queen Mary University of London.

The results appear June 20 in the journal Nature Communications.

The slow trill of the swamp sparrow can be heard in marshes and wetlands across eastern and central North America.

A grey-breasted bird with brownish wings, the swamp sparrow attracts mates and defends his territory with songs built from two- to five-note snippets, repeated over and over.

Researchers observed decades ago that swamp sparrows living in different places sing slightly different songs. Birds in New York might tend to sing in three-note repeats while their counterparts in Minnesota favor four, or combine the same basic notes in a different order.

Young birds learn the local customs in the first weeks of life by imitating their elders.

But while similar cultural traditions -- shared behaviors that are learned from others and passed from one generation to the next -- have been observed in all sorts of animals, the thinking has been that human traditions are more likely to last.

To test the idea, the researchers recorded the songs of 615 male swamp sparrows in six populations across New York, Pennsylvania, Michigan and Wisconsin.

Using computer software to measure and analyze each song, the team identified 160 song types across the species' range.

Each male has only a handful of songs in his repertoire. To figure out how young birds choose which songs to learn, the researchers developed a mathematical model that simulates how each new song type spreads within groups over time.

Each run of the model represented 5,000 years, at the end of which the researchers measured the song types in each group of birds.

With their model they also compared various song-learning strategies. For example, young birds might prefer to imitate one particular adult, such as their dad or a male with a good territory. Alternately, they might pick certain songs because they find them inherently more attractive, regardless of who sings them.

When they looked at how well their simulations fit the real data, the researchers found that young birds don't just randomly pick any song they hear and imitate that.

Instead, they copy the crowd, mimicking the most popular songs more often than one would expect by chance. Unique or rare songs that go against the mainstream rarely get a peep.

"It's called a 'conformist bias'," Lachlan said.

What's more, swamp sparrows learn their songs with amazing fidelity, correctly matching the songs they attempt to imitate more than 98 percent of the time.

There's an evolutionary benefit to fitting in, the researchers say. Previous studies show that females prefer typical tunes over outliers.

The end result, their models show, is that local song customs in swamp sparrows are far from fleeting trends, quickly going out of fashion and never to be uttered again.

Instead, they are handed down from one swamp sparrow generation to the next, with song types often persisting for 500 years or more, the researchers estimate.

The study also shows that creating traditions that pass the test of time doesn't necessarily require exceptional smarts.

The birds need not keep track of how many birds are singing each song to figure out how to fit in, the analyses show. They memorize a variety of songs early in life, from multiple older birds, but once they reach adulthood they only keep the songs they repeatedly hear others singing.

"The longstanding stable traditions so characteristic of human behavior have often been ascribed to the high cognitive abilities of humans and our ancestors," said study co-author Stephen Nowicki, professor of biology at Duke. "But what we're showing is that a relatively simple set of rules that these songbirds are capable of following can achieve equally lasting traditions."

"We're not saying that birds have anything akin to human culture," Lachlan said. "It shows that just those two ingredients -- a preference for popular songs, and the ability to copy them -- can get you quite a long way to having stable complex culture."

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Dogs understand what's written all over your face

Dogs can understand emotional expressions of humans.

Dogs are capable of understanding the emotions behind an expression on a human face. For example, if a dog turns its head to the left, it could be picking up that someone is angry, fearful or happy. If there is a look of surprise on a person's face, dogs tend to turn their head to the right. The heart rates of dogs also go up when they see someone who is having a bad day, say Marcello Siniscalchi, Serenella d'Ingeo and Angelo Quaranta of the University of Bari Aldo Moro in Italy. The study in Springer's journal Learning & Behavior is the latest to reveal just how connected dogs are with people. The research also provides evidence that dogs use different parts of their brains to process human emotions.

By living in close contact with humans, dogs have developed specific skills that enable them to interact and communicate efficiently with people. Recent studies have shown that the canine brain can pick up on emotional cues contained in a person's voice, body odour and posture, and read their faces.

In this study, the authors watched what happened when they presented photographs of the same two adults' faces (a man and a woman) to 26 feeding dogs. The images were placed strategically to the sides of the animals' line of sight and the photos showed a human face expressing one of the six basic human emotions: anger, fear, happiness, sadness, surprise, disgust or being neutral.

The dogs showed greater response and cardiac activity when shown photographs that expressed arousing emotional states such as anger, fear and happiness. They also took longer to resume feeding after seeing these images. The dogs' increased heart rate indicated that in these cases they experienced higher levels of stress.

In addition, dogs tended to turn their heads to the left when they saw human faces expressing anger, fear or happiness. The reverse happened when the faces looked surprised, possibly because dogs view it as a non-threatening, relaxed expression. These findings therefore support the existence of an asymmetrical emotional modulation of dogs' brains to process basic human emotions.

"Clearly arousing, negative emotions seem to be processed by the right hemisphere of a dog's brain, and more positive emotions by the left side," says Siniscalchi.

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Clovis site: Montana burial site answers questions about early humans

The burial mound at the Anzick site.

Scientists have shown that at the Anzick site in Montana -- the only known Clovis burial site -- the skeletal remains of a young child and the antler and stone artifacts found there were buried at the same time, raising new questions about the early inhabitants of North America, says a Texas A&M University professor involved in the research.

Michael Waters, director of the Center for the Study of the First Americans and colleagues from the University of Oxford and Stafford Research of Colorado have had their work published in the current issue of PNAS (Proceedings of the National Academy of Sciences).

The main focus of the team's research centered on properly dating the Anzick site which is named after the family who own the land. The site was discovered in 1968 by construction workers, who found the human remains and stone tools which include Clovis spear points and antler tools. It is the only known Clovis burial site and is associated with Clovis stone and antler artifacts.

"One thing that has always been a problem has been the accurate dating of the human remains from the site," explains Waters.

"The human remains yielded a younger age that was not in agreement with the ages from the antler artifacts which dated older than the human remains. If the human remains and Clovis artifacts were contemporaneous, they should be the same age." To resolve the issue, the team used a process called Specific Amino Acid Radiocarbon Dating, which allows a specific amino acid, in this case hydroxyproline, to be isolated from the human bones.

"This amino acid could only have come from the human skeleton and could not be contaminated," Waters adds.

"The other previous ages suffered from some sort of contamination. With the new method, we got very accurate and secure ages for the human remains based on dating hydroxyproline. As a test, we also redated the antler artifacts using this technique."

The results prove that both the human remains and antler Clovis artifacts are of the same date.

"The human remains and Clovis artifacts can now be confidently shown to be the same age and date between 12,725 to 12,900 years ago," Waters notes. "This is right in the middle to the end of the Clovis time period which ranges from 13,000 to 12,700 years ago.

"This is important because we have resolved the dating issues at the site. Some researchers had argued that the human remains were not Clovis and were younger than the Clovis artifacts, based on the earlier radiocarbon dates. We have shown that they are the same age and confirmed that the Anzick site represents a Clovis burial."

While not the earliest inhabitants of the Americas, Clovis is the first widespread prehistoric culture that first appeared 13,000 years ago. Clovis originated south of the large Ice Sheets that covered Canada at that time and are the direct descendants of the earliest people who arrived in the New World around 15,000 years ago. Clovis people fashioned their stone spear tips with grooved, or fluted, bases. They invented the "Clovis point,' a spear-shaped weapon made of stone that is found in Texas and other portions of the United States and northern Mexico, and these weapons were used to hunt animals.

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Two new creatures discovered from dawn of animal life

Two new Ediacaran-era fossils discovered by UCR researchers: Obamus coronatus (left) and Attenborites janeae.

Earth's first complex animals were an eclectic bunch that lived in the shallow oceans between 580-540 million years ago.

The iconic Dickinsonia -- large flat animals with a quilt-like appearance -- were joined by tube-shaped organisms, frond-like creatures that looked more like plants, and several dozen other varieties already characterized by scientists.

Add to that list two new animals discovered by a UC Riverside-led team of researchers:

• Obamus coronatus, a name that honors President Barack Obama's passion for science. This disc-shaped creature was between 0.5-2 cm across with raised spiral grooves on its surface. Obamus coronatus did not seem to move around, rather it was embedded to the ocean mat, a thick layer of organic matter that covered the early ocean floor.
• Attenborites janeae, named after the English naturalist and broadcaster Sir David Attenborough for his science advocacy and support of paleontology. This tiny ovoid, less than a centimeter across, was adorned with internal grooves and ridges giving it a raisin-like appearance.

The discovery of Obamus coronatus was published online June 14 in the Australian Journal of Earth Sciences, or AJES, and the Attenborites janeae paper is forthcoming in the same journal. The studies were led by Mary Droser, a professor of paleontology in UCR's Department of Earth Sciences. Both papers will be included in print in a 2019 thematic AJES issue focusing on South Australia's Flinders Ranges region, where the discoveries were made.

Part of the Ediacara Biota, the soft-bodied animals are visible as fossils cast in fine-grained sandstone that have been preserved for hundreds of millions of years. These Precambrian lifeforms represent the dawn of animal life and are named after the Ediacara Hills in the Flinders Ranges, the first of several areas in the world where they have been found.

In the hierarchical taxonomic classification system, the Ediacara Biota are not yet organized into families, and little is known about how they relate to modern animals. About 50 genera have been described, which often have only one species.

"The two genera that we identified are a new body plan, unlike anything else that has been described," Droser said. "We have been seeing evidence for these animals for quite a long time, but it took us a while to verify that they are animals within their own rights and not part of another animal."

The animals were glimpsed in a particularly well-preserved fossil bed described in another paper published by Droser's group that will be included in the Flinders Ranges issue of AJES. The researchers dubbed this fossil bed "Alice's Restaurant Bed," a tribute to the Arlo Guthrie song and its lyric, "You can get anything you want at Alice's Restaurant."

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22,000-year-old panda from cave in Southern China belongs to distinct, long-lost lineage

This is a photograph of the Cizhutuo fossil.

Researchers who've analyzed ancient mitochondrial (mt)DNA isolated from a 22,000-year-old panda found in Cizhutuo Cave in the Guangxi Province of China -- a place where no pandas live today -- have revealed a new lineage of giant panda. The report, published in Current Biology on June 18, shows that the ancient panda separated from present-day pandas 144,000 to 227,000 years ago, suggesting that it belonged to a distinct group not found today.

The newly sequenced mitochondrial genome represents the oldest DNA evidence from pandas.

"Using a single complete mtDNA sequence, we find a distinct mitochondrial lineage, suggesting that the Cizhutuo panda, while genetically more closely related to present-day pandas than other bears, has a deep, separate history from the common ancestor of present-day pandas," says Qiaomei Fu from the Chinese Academy of Sciences. "This really highlights that we need to sequence more DNA from ancient pandas to really capture how their genetic diversity has changed through time and how that relates to their current, much more restricted and fragmented habitat."

Very little has been known about pandas' past, especially in regions outside of their current range in Shaanxi province or Gansu and Sichuan provinces. Evidence suggests that pandas in the past were much more widespread, but it's been unclear how those pandas were related to pandas of today.

In the new study, the researchers used sophisticated methods to fish mitochondrial DNA from the ancient cave specimen. That's a particular challenge because the specimen comes from a subtropical environment, which makes preservation and recovery of DNA difficult.

The researchers successfully sequenced nearly 150,000 DNA fragments and aligned them to the giant panda mitochondrial genome reference sequence to recover the Cizhutuo panda's complete mitochondrial genome. They then used the new genome along with mitochondrial genomes from 138 present-day bears and 32 ancient bears to construct a family tree.

Their analysis shows that the split between the Cizhutuo panda and the ancestor of present-day pandas goes back about 183,000 years. The Cizhutuo panda also possesses 18 mutations that would alter the structure of proteins across six mitochondrial genes. The researchers say those amino acid changes may be related to the ancient panda's distinct habitat in Guangxi or perhaps climate differences during the Last Glacial Maximum.

The findings suggest that the ancient panda's maternal lineage had a long and unique history that differed from the maternal lineages leading to present-day panda populations. The researchers say that their success in capturing the mitochondrial genome also suggests that they might successfully isolate and analyze DNA from the ancient specimen's much more expansive nuclear genome.

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Best evidence of rare black hole captured

This image shows data from NASA/ESA's Hubble Space Telescope (yellow-white) and NASA's Chandra X-ray Observatory (purple). The purple-white source in the lower left shows X-ray emission from the remains of a star that was ripped apart as it fell towards an intermediate mass black hole. The host galaxy of the black hole is located in the middle of the image.

Scientists have been able to prove the existence of small black holes and those that are super-massive but the existence of an elusive type of black hole, known as intermediate-mass black holes (IMBHs) is hotly debated. New research coming out of the Space Science Center at the University of New Hampshire shows the strongest evidence to date that this middle-of-the-road black hole exists, by serendipitously capturing one in action devouring an encountering star.

"We feel very lucky to have spotted this object with a significant amount of high quality data, which helps pinpoint the mass of the black hole and understand the nature of this spectacular event," says Dacheng Lin, a research assistant professor at UNH's Space Science Center and the study's lead author. "Earlier research, including our own work, saw similar events, but they were either caught too late or were too far away."

In their study, published in Nature Astronomy, researchers used satellite imaging to detect for the first time this significant telltale sign of activity. They found an enormous multiwavelength radiation flare from the outskirts of a distant galaxy. The brightness of the flare decayed over time exactly as expected by a star disrupting, or being devoured, by the black hole. In this case, the star was disrupted in October 2003 and the radiation it created decayed over the next decade. The distribution of emitted photons over the energy depends on the size of the black hole. This data provides one of the very few robust ways to weight, or determine the size of, the black hole.

Researchers used data from a trio of orbiting X-ray telescopes, NASA's Chandra X-ray Observatory and Swift Satellite as well as ESA's XMM-Newton, to find the multiwavelength radiation flares that helped identify the otherwise uncommon IMBHs. The characteristic of a long flare offers evidence of a star being torn apart and is known as a tidal disruption event (TDE). Tidal forces, due to the intense gravity from the black hole, can destroy an object -- such as a star -- that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inward, and is ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare. According to the researchers, these types of flares, can easily reach the maximum luminosity and are one of the most effective way to detect IMBHs.

"From the theory of galaxy formation, we expect a lot of wandering intermediate-mass black holes in star clusters," said Lin. "But there are very, very few that we know of, because they are normally unbelievably quiet and very hard to detect and energy bursts from encountering stars being shredded happen so rarely."

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Primates in peril

Primates are fascinating. They are intelligent, live in complex societies and are a vital part of the ecosystem. Lemurs, lorises, galagos, tarsiers, monkeys and apes are our closest biological relatives and just like them, humans are also primates. However, while the human population spread to all corners of the earth, many of our closest relatives are under serious threat. An international team of leading primate researchers, including Christian Roos of the German Primate Center (DPZ) -- Leibniz Institute for Primate Research, has analyzed and evaluated the situation of many endangered non-human primate species in Brazil, Madagascar, Indonesia and the Democratic Republic of the Congo in a review article published today. In their study, the researchers investigated the influence of human activities on wild primate populations.

The destruction of natural forests and their conversion into agricultural land, threatens many species who thereby lose their habitat. However, hunting and the bushmeat trade also lead to a massive and rapid decline of many populations. A simulation of agricultural land expansion by the end of the century showed a decline of up to 78 percent in the distribution areas of many primate species. In their study, the scientists ask for immediate measures to protect the endangered primate species and supply recommendations for the long-term conservation of primates and to avert primate extinction (Peer Journal 2018).

Primates live in tropical and subtropical areas and are mainly found in regions of Africa, South America, Madagascar and Asia. The International Union for Conservation of Nature (IUCN) currently lists 439 species. 65 percent (286) of these are located in the four countries Brazil, Indonesia, Madagascar and the Democratic Republic of Congo. Around 60 percent of them are threatened by extinction. Particularly dire is the situation in Indonesia and Madagascar, where 90 percent of primate population declined and more than three-quarters of species are endangered.

In a comprehensive literature review, the authors of the study analyzed the major threat factors for primates in four countries. In Brazil, Madagascar and Indonesia the increasing destruction of their habitats is a stressor for the animals. In the Democratic Republic of the Congo, the bushmeat trade is the biggest threat. In addition, primates are sold illegally as pets or used in traditional medicine. Poverty, the lack of education, food insecurity, political instability and corruption further encourage the depletion of natural resources in the countries concerned and make it more difficult to protect the animals.

"The destruction of the natural environment through deforestation, the expansion of agricultural land and infrastructure development to transport goods has become a major problem," says Christian Roos, a scientist in the Primate Genetics Laboratory at the DPZ and co-author of the study. "The main contributors of this development are the industrial nations. There is a high demand for raw materials such as soy, palm oil, rubber, hardwood or fossil fuel. The four primate-rich countries cover 50 percent of these export goods to China, India, the US and Europe."

The scientists combined data from the United Nations and World Bank databases to simulate the estimated spread of agricultural land in the four countries until the turn of the century. Assuming a worst-case scenario, the researchers were able to predict a decline in the geographical range of the primate populations. Accordingly, by the year 2100 78 percent of the primate habitats in Brazil, 72 percent in Indonesia, 62 percent in Madagascar and 32 percent in the Congo could have disappeared. At the same time, the authors investigated the size and distribution of protected areas. Their estimates show that Brazil and Madagascar have around 38 percent, Indonesia 17 percent, and The Democratic Republic of Congo 14 percent of primate habitats in protected areas. The majority of the distribution areas are without protection status and primates are therefore under threat.

The authors call for the extension of protected areas, the reforestation of forests and the planting of corridors as important measures to preserve primate populations. In addition, the local population must be made aware of the precarious situation. Governments, scientists, conservation organizations and economists need to work together to promote sustainable, organic farming while preserving traditional lifestyles. In addition, the governments of the countries concerned should work harder to combat illegal hunting, forest destruction and primate trade.

Read more at Science Daily

Gut microbes may contribute to depression and anxiety in obesity

Like everyone, people with type 2 diabetes and obesity suffer from depression and anxiety, but even more so. Researchers at Joslin Diabetes Center now have demonstrated a surprising potential contributor to these negative feelings -- and that is the bacteria in the gut or gut microbiome, as it is known.

Studying mice that become obese when put on a high-fat diet, the Joslin scientists found that mice on a high-fat diet showed significantly more signs of anxiety, depression and obsessive behavior than animals on standard diets. "But all of these behaviors are reversed or improved when antibiotics that will change the gut microbiome were given with the high fat diet," says C. Ronald Kahn, M.D., co-Head of the Section on Integrative Physiology and Metabolism at Joslin and the Mary K. Iacocca Professor of Medicine at Harvard Medical School .

"As endocrinologists, we often hear people say that they feel differently when they've eaten different foods," notes Kahn, who is senior author on a paper in Molecular Psychiatry describing the research. "What this study says is that many things in your diet might affect the way your brain functions, but one of those things is the way diet changes the gut bacteria or microbes. Your diet isn't always necessarily just making your blood sugar higher or lower; it's also changing a lot of signals coming from gut microbes and these signals make it all the way to the brain."

His lab has long studied mice that are prone to developing obesity, diabetes and related metabolic diseases when given high-fat diets. Earlier this year, the team showed that at least part of this development is driven by changing bacteria in the gut microbiome. The condition was reversed in mice who were given antibiotics in their drinking water, which altered the microbiome.

In the most recent study, the Joslin scientists followed up by giving mice on a high-fat diet four classic lab animal behavioral tests, which are often employed in screening drugs for anxiety and depression. In each case, mice on high-fat diet showed higher signs of anxiety and depression than mice on a regular diet. However, when the mice were given antibiotics with the high fat diet, their behaviors returned to normal.

One of the ways the researchers showed this was an effect of the microbiome was by transferring gut bacteria from these experimental mice toto germ-free mice, who did not have any bacteria of their own. The animals who received bacteria from mice on a high-fat diet showed began to show increased levels of activity associated with anxiety and obsessive behavior. However, those who received microbes from mice on a high-fat diet plus antibiotics did not, even though they did not receive the antibiotics themselves. "This proves that these behaviors are driven to some significant extent by the gut microbiome," says Kahn.

But what exactly were the microbes doing? The Joslin looked for clues in two areas of the brain, the hypothalamus (which helps to control whole body metabolism) and the nucleus accumbens (which is important in mood and behavior).

"We demonstrated that, just like other tissues of the body, these areas of the brain become insulin resistant in mice on high-fat diets," Kahn says. "And this response to the high fat is partly, and in some cases almost completely, reversed by putting the animals by antibiotics. Again, the response is transferrable when you transfer the gut microbiome from mice on a high-fat diet to germ-free mice. So, the insulin resistance in the brain is mediated at least in part by factors coming from the microbiome."

The Joslin team went on to link the microbiome alterations to the production of certain neurotransmitters -- the chemicals that transfer signals across the brain.

Kahn and his colleagues are now working to identify specific populations of bacteria involved in these processes, and the molecules that the bacteria produce. The eventual goal is to find drugs or supplements that can help to achieve healthier metabolic profiles in the brain.

"Antibiotics are blunt tools that change many bacteria in very dramatic ways," Kahn says. "Going forward, we want to get a more sophisticated understanding about which bacteria contribute to insulin resistance in the brain and in other tissues. If we could modify those bacteria, either by putting in more beneficial bacteria or reducing the number of harmful bacteria, that might be a way to see improved behavior."

Read more at Science Daily

In the gaping mouth of ancient crocodiles

This is a digital model of the skull still enclosed in matrix.

The mouth of today's crocodilians inspires fear and awe, with their wide gape and the greatest known bite force in the vertebrate animal kingdom. However, this apex predator of today and its modus of attack (its mouth) had humble beginnings.

The very earliest crocodilians were very different to the beasts we know well today, they were much smaller bodied, slender and had longer legs. It is speculated that they led a much different lifestyle to the crocodiles we all know and fear today.

A new study by a team of international experts, led by University of Witwatersrand PhD candidate Kathleen Dollman and Professor Jonah Choiniere published today in the American Museum Novitates, endeavoured to further explore the mouth of one of the earliest occurring and least understand groups of crocodilians, the shartegosuchids.

In 2010, Choiniere was a part of a field team working in the Late Jurassic (±160 mya) exposures in the western Gobi in Mongolia, when he found the fossil of a small snout of a shartegosuchid. This work was co-authored by researchers based at the American Museum of Natural History, the George Washington University and the Institute for Vertebrate Palaeontology and Palaeoanthropology.

The snout was later CT scanned at the American Museum of Natural History, exposing an unusual, closed secondary palate. Crocodilians are one of only a few groups of animals that evolve a completely closed, bony secondary palate (along with turtles and mammals). A closed secondary palate has many biological implications for crocodilians, including breathing whilst under water and reinforcing the skull to allow for their incredible bite force.

This study showed that these early crocodilians, the shartegosuchids, are important because they evolved a completely closed secondary palate much earlier than previously thought. This is an interesting example of convergent evolution, whereby a similar feature evolves independently in two completely unrelated groups. The advent of a convergent evolutionary event allows scientists to test questions about why that feature evolved and even the function of that feature which in this case is the first step in understanding the purpose of a closed secondary palate in crocodilians.

"I was surprised to find that there were many features in the palate and snout that were completely different between shartegosuchids and extant crocodilians," says Dollman. Shartegosuchids have a thickened and sculptured palate together with a tall and short rostrum, whereas extant crocodilians have a smooth palate with a long and broad rostrum.

"We would expect to see the same palatal structures and snout shapes in both shartegosuchids and extant crocodiles if they were using it for similar functions and had evolved a closed palate for similar reasons," says Dollman. "The observed differences tell us that shartegosuchids likely had predation practices to which there is no modern analogue in crocodilians."

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Hunting molecules to find new planets

The planet becomes visible when looking for H2O or CO molecules. However, as there is no CH4 nor NH3 in its atmosphere, it remains invisble when looking for these molecules, just as its host star which contains none of those four elements.

Each exoplanet revolves around a star, like the Earth around the Sun. This is why it is generally impossible to obtain images of an exoplanet, so dazzling is the light of its star. However, a team of astronomers, led by a researcher from the University of Geneva (UNIGE) and member of NCCR PlanetS, had the idea of detecting certain molecules that are present in the planet's atmosphere in order to make it visible, provided that these same molecules are absent from its star. Thanks to this innovative technique, the device is only sensitive to the selected molecules, making the star invisible and allowing the astronomers to observe the planet directly. The results appear in the journal Astronomy & Astrophysics.

Until now, astronomers could only very rarely directly observe the exoplanets they discovered, as they are masked by the enormous luminous intensity of their stars. Only a few planets located very far from their host stars could be distinguished on a picture, in particular thanks to the SPHERE instrument installed on the Very Large Telescope (VLT) in Chile, and similar instruments elsewhere. Jens Hoeijmakers, researcher at the Astronomy Department of the Observatory of the Faculty of Science of the UNIGE and member of NCCR PlanetS, wondered if it would be possible to trace the molecular composition of the planets. "By focusing on molecules present only on the studied exoplanet that are absent from its host star, our technique would effectively "erase" the star,leaving only the exoplanet," he explains.

Erasing the star thanks to molecular spectra

To test this new technique, Jens Hoeijmakers and an international team of astronomers used archival images taken by the SINFONI instrument of the star beta pictoris, which is known to be orbited by a giant planet, beta pictoris b. Each pixel in these images contains the spectrum of light received by that pixel. The astronomers then compared the spectrum contained in the pixel with a spectrum corresponding to a given molecule, for example water vapour, to see if there is a correlation. If there is a correlation, it means that the molecule is present in the atmosphere of the planet.

By applying this technique to beta pictoris b, Jens Hoeijmakers notices that the planet becomes perfectly visible when he looks for water (H2O) or carbon monoxide (CO). However, when he applies his technique to methane (CH4) and ammonia (NH3), the planet remains invisible, suggesting the absence of these molecules in the atmosphere of beta pictoris b.

Molecules, new planetary thermometer

The host star beta pictoris remains invisible in all four situations. Indeed, this star is extremely hot and at this high temperature, these four molecules are destroyed. "This is why this technique allows us not only to detect elements on the surface of the planet, but also to sense the temperature which reigns there," explains the astronomer of the UNIGE. The fact that astronomers cannot find beta pictoris b using the spectra of methane and ammonia is therefore consistent with a temperature estimated at 1700 degrees for this planet, which is too high for these molecules to exist.

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Simple chemical process that may have led to the origin of life on Earth

A wet-dry scenario in a prebiotic hot spring or tidal pool. A) shows the pool with the five kinds of alpha hydroxy acids used in this study. B) shows the drying pool where a "library" of polyesters, depicted as the inset high-resolution mass spectra) forms at the drying edges. This simple formation of polyesters could have played a role in scaffolding the origins of life.

Research led by Kuhan Chandru and Jim Cleaves from the Earth-Life Science Institute at Tokyo Institute of Technology, Japan, has shown that reactions of alpha-hydroxy acids, similar to the alpha-amino acids that make up modern proteins, form large polymers easily under conditions presumed prevalent on early Earth. These alpha-hydroxy acid polymers may have aided in the formation of living systems on early Earth.

There are different theories for how life first formed on early Earth. One popular one suggests that life may have arisen in specialized environments, such as tidal pools or shallow water hot springs, where simple chemical reactions would have helped generate life's precursors. All life is made up of polymers, large molecules made up of a sequence of molecules called monomers. A key question is how biological polymers could have formed without enzymes on early Earth.

While environments of early Earth might have had monomers that could give rise to life, it would have been difficult for polymers to arise from these without the help of enzymes. In this case, the team showed these polymers could have formed with alpha-hydroxy acids before the existence of enzymes on early Earth.

This multi-national team showed that hydroxy acids polymerize more easily than amino acids, and that they could have provided the necessary toolkit to kick-start the formation of more complex molecules for the origin of life on Earth.

To simulate various primitive environments, the team reacted alpha hydroxy acids under varied conditions of pH and temperature, from room temperature to boiling hot. Using sophisticated high-resolution mass spectrometry and data analysis software, they showed that these polymers can form over a range of conditions.

The team showed further, that using a mixture of different types of alpha-hydroxy acid that they could form huge numbers of types of polymers, in effect creating vast 'libraries' of different chemical structures, which can remain stable over a range of environmental conditions. The work culminated with the creation of a polyester library made up of five kinds of alpha hydroxy acids. They showed that this simple-to-create library could contain hundreds of trillions of distinct polymer sequences.

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Gene therapy restores hand function after spinal cord injury in rats

This is active neural connections in rat spinal cord.

Researchers at King's College London have shown that rats with spinal cord injuries can re-learn skilled hand movements after being treated with a gene therapy.

People with spinal cord injury often lose the ability to perform everyday actions that require coordinated hand movements, such as writing, holding a toothbrush or picking up a drink. Regaining hand function is the top priority for patients and would dramatically improve independence and quality of life. No regenerative treatments are currently available.

The researchers tested a new gene therapy for regenerating damaged tissue in the spinal cord that could be switched on and off using a common antibiotic.

Professor Elizabeth Bradbury from the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) said: 'What is exciting about our approach is that we can precisely control how long the therapy is delivered by using a gene 'switch'. This means we can hone in on the optimal amount of time needed for recovery. Gene therapy provides a way of treating large areas of the spinal cord with only one injection, and with the switch we can now turn the gene off when it is no longer needed.'

After a traumatic spinal injury, dense scar tissue forms which prevents new connections being made between nerve cells. The gene therapy causes cells to produce an enzyme called chondroitinase which can break down the scar tissue and allow networks of nerve cells to regenerate.

Most human spinal cord injuries occur at the neck level and affect all four limbs. The researchers gave the gene therapy to rats with spinal injuries that closely mimicked the kind of human spinal injuries that occur after traumatic impacts such as car crashes or falls.

Dr Emily Burnside from the IoPPN explains: 'Rats and humans use a similar sequence of coordinated movements when reaching and grasping for objects. We found that when the gene therapy was switched on for two months the rats were able to accurately reach and grasp sugar pellets. We also found a dramatic increase in activity in the spinal cord of the rats, suggesting that new connections had been made in the networks of nerve cells.'

The researchers had to overcome a problem with the immune system recognising and removing the gene switch mechanism. To get around this, the researchers worked with colleagues in the Netherlands to add a 'stealth gene' which hides the gene switch from the immune system.

Professor Joost Verhaagen at the Netherlands Institute for Neuroscience says: 'The use of a stealth gene switch provides an important safeguard and is an encouraging step toward an effective gene therapy for spinal cord injury. This is the first time a gene therapy with a stealth on/off switch has been shown to work in animals.'

The gene therapy is not yet ready for human trials. While the ability to switch a therapeutic gene off provides a safeguard, the researchers found a small amount of the gene remained active even when switched off. They are now working on shutting the gene down completely and moving towards trials in larger species.

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