Sep 3, 2016

EEG recordings prove learning foreign languages can sharpen our minds

Learning a foreign language helps the brain.
Scientists from the Higher School of Economics (HSE) together with colleagues from the University of Helsinki have discovered that learning foreign languages enhances the our brain's elasticity and its ability to code information. The more foreign languages we learn, the more effectively our brain reacts and processes the data accumulated in the course of learning. An article of Yury Shtyrov, Leading Research Fellow of the HSE Centre for Cognition & Decision Making, Lilli Kimppa and Teija Kujala (University of Helsinki) summarizing the new findings has been recently published in Scientific Reports.

According to the study, the neurophysiological mechanics of language and speech acquisition are underexplored when compared to the brain's other functions. The reason for such scarce attention is the inability to study verbal function on test animals.

Researchers carried out experiments where the brain's electrical activity was measured with EEG (electroencephalography). Twenty-two students in total (10 male and 12 female) participated in the investigation, with the average age being 24. The subjects had electrodes placed on their heads and then listened to recordings of different words in their native language, as well in foreign languages, both known and completely unknown by the subjects. When the known or unknown words popped up, changes in the brain's activity were tracked. Researchers especially focused on the speed at which the brain readjusted its activity to treat unknown words. Afterwards, the accrued neurophysiological data was compared to the subjects' linguistic background: how many languages they knew, at which age they started to learn it, and so on. Apparently, the ability of the brain to quickly process information depends on one's "linguistic anamneses."

The experiment has shown that the brain's electrical activity of those participants who had already known some foreign languages, was higher. The author of the study, Yuriy Shtyrov commented that the more languages someone mastered, the faster the neuron network coding the information on the new words was formed. Consequently, this new data stimulates the brain's physiology: loading the mind with more knowledge boosts its elasticity.

Read more at Science Daily

One vent just isn't enough for some volcanoes: Curious case of Mount Etna's wandering craters

Lava fountaining episode occurred on Nov. 17, 2013, at the New South-East Crater.
Volcanoes are geology at its most exciting. They seem so fiery, dangerous and thrillingly explosive. That may be true, but most old and mature volcanoes are surprisingly stuck in their ways and even if when they will blow is difficult to forecast, where they will blow from is often more predictable.

The majority of volcanoes look as they do in a child's drawing; like a steep mountain with its head cut off. They have a summit crater and, if they erupt, it is from this rocky orifice that lava and ash spews. But this is not the case with Mount Etna on the Island of Sicily, Italy, a study published in the open-access journal Frontiers in Earth Science found.

Etna has been collecting new summits as though they are Pokémon. It is as if the mountain has had an outbreak of acne, with multiple cones forming in a geologically short space of time. According to Professor Valerio Acocella, of Roma Tre University and his colleagues from Ingv Catania, this makes Etna "perfect for study."

Valerio and his fellow researchers have been using data collected over the past ten years from thermal imaging satellites, ground measurements and onsite monitoring of the volcano to document its unruly behavior and try and work out why it has more vents than most volcanoes.

Valerio claims that "the fact that Etna is continuously active allows us to capture many evolutionary processes, within a decade or less, which, at any other volcano would (only) be seen over much larger spans of decades or centuries." As a consequence, "Etna is probably one of the best monitored and studied volcanoes in the world."

The team observed how over the past few decades eruptions have moved from a central crater to a new one developed to its south, before that too was soon abandoned and another cone, to the southeast, quickly formed and rose to dominance. The researchers attribute this wandering eruptive activity to an instability on the volcano's eastern flank.

It is as if the mountain is suffering subsidence, with the weight of the summit being undercut by the movement of the volcano's lower portion to the east. This is causing new stresses and pressures to the structure as a whole. But this is more than just an academic study seeking to understand the history of a world famous and fascinating volcano.

Read more at Science Daily

Sep 2, 2016

A strange thing happened in the stratosphere

A predictable pattern of winds in the stratosphere recently changed in a way scientists had not seen in more than 60 years of record-keeping.
This disruption to the wind pattern -- called the "quasi-biennial oscillation" -- did not have any immediate impact on weather or climate as we experience it on Earth's surface. But it does raise interesting questions for the NASA scientists who observed it: If a pattern holds for six decades and then suddenly changes, what caused that to happen? Will it happen again? What effects might it have?

"The quasi-biennial oscillation is the stratosphere's Old Faithful," said Paul Newman, Chief Scientist for Earth Sciences at NASA's Goddard Space Flight Center, Greenbelt, Maryland, and lead author on a new paper about the event published online in Geophysical Research Letters. "If Old Faithful stopped for a day, you'd begin to wonder about what was happening under the ground."

Winds in the tropical stratosphere, an atmospheric layer that extends from about 10 to 30 miles above Earth's surface, circulate the planet in alternating easterly and westerly directions over roughly a two-year period. Westerly winds develop at the top of the stratosphere, and gradually descend to the bottom, about 10 miles above the surface while at the same time being replaced by a layer of easterly winds above them. In turn, the easterlies descend and are replaced by westerlies.

This pattern repeats every 28 months. In the 1960s scientists coined it the "quasi-biennial oscillation." The record of these measurements, made by weather balloons released in the tropics at various points around the globe, dates to 1953.

The pattern never changed -- until late 2015. As the year came to a close, winds from the west neared the end of their typical descent. The regular pattern held that weaker easterly winds would soon replace them. But then the westerlies appeared to move upwards and block the downward movement of the easterlies. This new pattern held for nearly half a year, and by July 2016 the old regime seemed to resume.

"It's really interesting when nature throws us a curveball," Newman said.

The quasi-biennial oscillation has a wide influence on stratospheric conditions. The amount of ozone at the equator changes by 10 percent between the peaks of the easterly and westerly phases, while the oscillation also has an impact on levels of polar ozone depletion.

Read more at Science Daily

Jupiter's north pole unlike anything encountered in solar system

Storm systems and weather activity unlike anything encountered in the solar system are on view in these color images of Jupiter's north polar region from NASA's Juno spacecraft. Two versions of the image have been contrast-enhanced differently to bring out detail near the dark terminator and near the bright limb. The JunoCam instrument took the images to create this color view on August 27, when the spacecraft was about 48,000 miles (78,000 kilometers) above the polar cloud tops.
NASA's Juno spacecraft has sent back the first-ever images of Jupiter's north pole, taken during the spacecraft's first flyby of the planet with its instruments switched on. The images show storm systems and weather activity unlike anything previously seen on any of our solar system's gas-giant planets.

Juno successfully executed the first of 36 orbital flybys on Aug. 27 when the spacecraft came about 2,500 miles (4,200 kilometers) above Jupiter's swirling clouds. The download of six megabytes of data collected during the six-hour transit, from above Jupiter's north pole to below its south pole, took one-and-a-half days. While analysis of this first data collection is ongoing, some unique discoveries have already made themselves visible.

"First glimpse of Jupiter's north pole, and it looks like nothing we have seen or imagined before," said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. "It's bluer in color up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to -- this image is hardly recognizable as Jupiter. We're seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features."

One of the most notable findings of these first-ever pictures of Jupiter's north and south poles is something that the JunoCam imager did not see.

"Saturn has a hexagon at the north pole," said Bolton. "There is nothing on Jupiter that anywhere near resembles that. The largest planet in our solar system is truly unique. We have 36 more flybys to study just how unique it really is."

Along with JunoCam snapping pictures during the flyby, all eight of Juno's science instruments were energized and collecting data. The Jovian Infrared Auroral Mapper (JIRAM), supplied by the Italian Space Agency, acquired some remarkable images of Jupiter at its north and south polar regions in infrared wavelengths.

"JIRAM is getting under Jupiter's skin, giving us our first infrared close-ups of the planet," said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. "These first infrared views of Jupiter's north and south poles are revealing warm and hot spots that have never been seen before. And while we knew that the first-ever infrared views of Jupiter's south pole could reveal the planet's southern aurora, we were amazed to see it for the first time. No other instruments, both from Earth or space, have been able to see the southern aurora. Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora's morphology and dynamics."

Among the more unique data sets collected by Juno during its first scientific sweep by Jupiter was that acquired by the mission's Radio/Plasma Wave Experiment (Waves), which recorded ghostly-sounding transmissions emanating from above the planet. These radio emissions from Jupiter have been known about since the 1950s but had never been analyzed from such a close vantage point.

"Jupiter is talking to us in a way only gas-giant worlds can," said Bill Kurth, co-investigator for the Waves instrument from the University of Iowa, Iowa City. "Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter's north pole. These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them."

Read more at Science Daily

New Cave Beetles Look Like Scary Spiders

Spelunkers in a Serbian cave may stumble across what appear to be spiders living on the rock walls and ceilings, but it turns out that some of these "spiders" are actually beetles, according to a new study.

New research reveals two new species of these spindle-legged cave beetles while also upending the creatures' family tree. The study, based on molecular analysis of the cave beetle DNA, created a new genus, Graciliella, which contains at least four species of the beetle.

The study was led by Iva Njunji?, a cave biologist at the University of Novi Sad in Serbia. Serbia, Montenegro, Croatia and nearby Balkan nations sit atop multiple cave systems, which are home to a variety of bizarre cave-adapted organisms. One example is the European cave salamander, or olm, a blind and colorless creature that navigates its environment through smell, touch and the detection of magnetic fields.

Cave beetles evolved from above-ground ancestors that looked like average, plump-bodied, short-legged beetles. The cave-adapted animal, though, has no eyes, no wings and no color. Its legs and antennae are extremely long, because the beetles compensate for the lack of eyesight with touch. These long appendages, combined with a fat hind part of the body that may help store fat during times of famine, give cave beetles their spidery appearance.

Because most animals that live their entire lives in caves develop similar characteristics — pale bodies, no eyes — it can be hard to discern subtle differences between species, the researchers said. So, Njunji? and her colleagues turned to molecular analysis to detect genetic differences between cave beetles collected in Montenegro, Bosnia and Herzegovina, and Croatia. Their results revealed that species assigned to the genus Anthroherpon actually descended from more than one common ancestor. Thus, the researchers spun off a new genus, Graciliella, containing species found in Montenegro and Croatia.

Read more at Discovery News

Declining Megafauna Having 'Dramatic Effects'

Elephants, rhinos, hippos and other megafauna are in steep decline now, which researchers find is having a disastrous impact on the environment and on smaller animals down the food chain.

Of particular concern at present is the overwhelming loss of African savanna elephants in recent years. Such pachyderms are declining by 30 percent in 15 of 18 countries surveyed, according to results of the three-year Great Elephant Census that were announced earlier this week. The census and accompanying African Elephant Atlas, produced by philanthropist Paul G. Allen's Vulcan, Inc., mark what is believed to be the largest ever Pan-African survey of savanna elephants.

Mike Chase, principal investigator for the Great Elephant Census, shares how the largest pan-Africa survey since the 1970s came to be, and how he hopes this data will save Africa's savanna elephants:

"Elephants are a keystone species that are essential in maintaining the biodiversity of ecosystems," James Deutsch, Vulcan Wildlife Conservation Director, told Discovery News, explaining that elephants positively affect not just one, but three types of landscapes: deserts, savannas and forests.

"In deserts," he explained, "elephants dig for water, providing water holes for other wildlife species. In savannas, they prevent the conversion of open grassland into dense bush -- enabling all of the grazing herbivores to survive. And in forests, they are critical seed dispersers -- many of the key rainforest tree species in Africa cannot regenerate without the fruits being eaten and the seeds transported and planted by elephants in their dung."

Elephants seen during a Great Elephant Census flight over Botswana.
 A 2014 conference at Oxford University, "Megafauna and ecosystem function: from the Pleistocene to the Anthropocene," came to similar conclusions, noting the ecosystem importance of elephants as well as other large terrestrial mammals.

In a paper summarizing the conference, University of New Mexico biologist Felisa Smith and her colleagues wrote: "One of the more pressing contemporary issues is the decline of megafauna and the loss of their ecological interactions within ecosystems. Across the Earth today, large animals are in peril, particularly predators."

It is estimated that a quarter of all such species are currently at risk of extinction. Two likely problems associated with the population declines are more frequent, intense wildfires and increased pressure on vegetation that sustains other life.

Regarding the former, Smith and her team explained that elephants decrease tree fuel loads in a natural way that reduces both the number of fires and their size. At present, it is believed that human activities, climate change and loss of megafauna are helping to drive an unprecedented number of wildfires around the globe. The Earth Island Institute, for example, reported that the six worst fire seasons in the past 50 years have all occurred since 2000.

As for increased pressure on vegetation, Smith and her team mention that large carnivores can generate "landscapes of fear," which sound awful, but actually wind up doing a lot of good.

During the Pleistocene Era (2.5 million to 11,700 years ago), for example, megafauna such as the scimitar cat, American lion, saber-tooth cat and short-faced bear -- all of which were larger than the modern African lion -- kept large numbers of plant-eating animals in check, such that vegetation remained relatively healthy and therefore was better able to support insects, birds, the herbivore prey species and more.

Recreation of a scimitar cat (Homotherium serum).
 Even then, humans were killing off large mammals. A recent study published in the Proceedings of the National Academy of Sciences found that between 50,000 and 10,000 years ago, an increase in global human populations contributed to a two-thirds reduction of 150 species of megafauna. Lead author Nicole Boivin from the University of Oxford and the Max Planck Institute for the Science of Human History and her team found that the disappearance of these large animals has had "dramatic effects" on the structure of the ecosystem as well as on seed dispersal.

The advent of agriculture worldwide and the domestication of animals raised for food has further inflicted "unprecedented and enduring effects" on the distribution of megafauna and other species, according to Boivin and her colleagues. They add that, in contrast with domesticated animals (dogs alone are estimated at numbering one billion now), the percentage of truly wild large animals today is "vanishingly small."

Read more at Discovery News

Sep 1, 2016

New Dinosaur Was a Middle Jurassic Monster

Meet the largest carnivorous dinosaur ever found in Germany, a two-ton monster with huge teeth that's just been deemed its own genus and species.

Writing in the journal Palaeontologia Electronica, researchers from Ludwig Maximilians University (LMU) in Munich discuss their analysis of fossilized bones and teeth of an enormous dinosaur from some 160 million years ago -- a meat-eating beast known to paleontologists as the "Monster of Minden" that they've named Wiehenvenator albati.

W. albati was a megalosaurid -- the earliest known group of large carnivores -- that weighed a bit more than 2 tons and was about 26 to 33 feet (8 to 10 meters) long. It stood on its hind legs, had shortened forelimbs and, according to a release from the scientists, had "teeth as big as bananas" that curved inward toward the pharynx.

The well-preserved bones were unearthed from the hills of a former quarry in northwestern Germany's Wiehengebirge mountain range, south of Minden. According to the researchers, the dinosaur likely lived on islands in shallow waters surrounding what is today central Europe.

A wide range of often large carnivorous dinosaurs lived on the islands. "Moreover, most of them belonged to the group known as the megalosaurids," said study co-author Oliver Rauhut, a paleontologist at LMU, in a statement.

The team says its analysis safely places W. albati as a new megalosaurid theropod, from the same broad group as Tyrannosaurus rex, during a time in the fossil record when a vast array of new species were arriving on the scene.

"Practically all the major groups of predatory dinosaurs originated during this period, including tyrannosaurs (which, however, only gave rise to their really gigantic representatives some 80 million years later) and the first direct ancestors of the birds," said Rauhut.

From Discovery News

No, That 'Interesting' SETI Signal Wasn't Aliens

Well that was quick. On Monday, speculation was rife that a signal from an alien civilization had been detected coming from a star system 94 light-years away. Today, we're coming to terms with the fact that the 11.1 GHz radio signal was actually produced by a Soviet era satellite.

In a statement from the Special Astrophysical Observatory of the Russian Academy of Sciences on Wednesday, astronomer Yulia Sotnikova said that "an interesting radio signal at a wavelength of 2.7 cm was detected" but "subsequent processing and analysis of the signal revealed its most probable terrestrial origin."


The strong radio burst was detected in May 15, 2015, by the RATAN-600 radio telescope in Zelenchukskaya, Russia, and reports of a document describing the "interesting" signal from the star system HD164595 appeared on the website Centauri Dreams. Although speculation as to the possible extraterrestrial intelligence implications was on everyone's minds, no one thought aliens were a high probability, only that it was worth further study.

A discussion was planned during a special SETI meeting at the 67th International Astronautical Congress (IAC) in Guadalajara, Mexico, in September.

Of course, the mere hint of discovering a candidate signal from an advanced extraterrestrial civilization was enough to work some mainstream media outlets into a frenzy while science journalists tried to inject some sanity into the proceedings, pointing out that the signal was overwhelmingly likely to be terrestrial in origin. But aliens remained the narrative and aliens kept hogging the headlines. It's a fundamental law of space journalism: even if alien life is just a remote possibility, alien life will become the story.

The problem with the speculative science of SETI is that there is a high probability of false positives. Strong signals are detected, but we live on a planet drenched in radio waves. To complicate matters, our planet is surrounded by satellites also blasting transmissions of various wavelengths back at our planet. It's a complex task to take a suspect SETI signal, analyze it and identify exactly what may have caused it.

And as the May 2015 signal hadn't even moved beyond the analysis phase, it's likely that the radio astronomers who found the signal were overtaken by its rumored existence and subsequent heavy media coverage.

Now it seems cold water has been thrown over the origin of the signal and Sotnikova emphasized the RATAN-600 radio telescope has yet to find any candidate SETI signals: "It can be said with confidence that no sought-for signal has been detected yet."

So what was it?

Read more at Discovery News

New Horizons Spies Distant Dwarf Planet Quaoar

NASA's New Horizons spacecraft has photographed a distant dwarf planet cruising through the dark depths of the outer solar system.

New Horizons captured images of the mysterious, 690-mile-wide (1,110 kilometers) Quaoar at four different times on July 13 and July 14 — exactly one year after the probe's historic July 14, 2015, flyby of Pluto.

New Horizons was 1.3 billion miles (2.1 billion km) from Quaoar when it took the photos with its Long Range Reconnaissance Imager (LORRI) camera, so the dwarf planet is not sharply resolved. But even such fuzzy views have scientific value, NASA officials said.

"With the oblique view available from New Horizons, LORRI sees only a portion of Quaoar's illuminated surface, which is very different from the nearly fully illuminated view of the dwarf planet from Earth," NASA officials wrote in an image description today (Aug. 31). "Comparing Quaoar from the two very different perspectives gives mission scientists a valuable opportunity to study the light-scattering properties of Quaoar's surface."

Quaoar (pronounced kwa-whar) was discovered in 2002 and has not officially been designated a dwarf planet, but it almost certainly qualifies, researchers have said. Dwarf planets need to be massive enough to be shaped into a sphere by their own gravity; with a diameter of 690 miles, Quaoar is larger than the officially recognized dwarf planet Ceres.

Quaoar lies an average of 43 astronomical units (AU) from the sun and completes one lap around the star every 286 Earth years. (One AU is the average distance from Earth to the sun — about 93 million miles, or 150 million km.) The object has one known moon.

The newly released images also show a number of background stars and two galaxies, known as IC 1048 and UGC 09485, both of which are about 370 billion times farther from New Horizons than Quaoar is, agency officials added.

As the Quaoar observations show, New Horizons' work did not end with the Pluto encounter. On Jan. 1, 2019, the probe will fly by an object called 2014 MU69, which lies about 1 billion miles (1.6 billion km) beyond Pluto.

Read more at Discovery News

New Pterosaur Species Found with Intact Skull

Shown is a paleoartist's reconstruction of a new species of pterosaur, Allkaruen koi.
A new species of pterosaur named for its "ancient brain" has been found in Patagonia.

The flying reptile lived in the early Jurassic period, between about 199.6 million years ago and 175.6 million years ago. Paleontologists found the new fossil in north central Chubut province in Argentina. To their delight, the fossil included an intact braincase, offering them a new look at pterosaur neuroanatomy.

The researchers named the new species Allkaruen koi. All means "brain," and karuen means "ancient," in Tehuelche, a language indigenous to Patagonia.

"Allkaruen, from the middle lower Jurassic limit, shows an intermediate state in the brain evolution of pterosaurs and their adaptations to the aerial environment," study researcher Diego Pol, a paleontologist at the Museo Paleontológico Egidio Feruglio in Argentina, said in a statement. "As a result, this research makes an important contribution to the understanding of the evolution of all of pterosaurs."

The new pterosaur was found in a bone bed that contains many pterosaur remains. Archaeologists uncovered a vertebra, jaws and a braincase. The braincase was only a few dozen millimeters long, indicating that it was from a small pterosaur species, the researchers said.

It's rare to find an intact pterosaur braincase, according to the researchers, and little has been known about the way pterosaur skulls (and thus brains) evolved over time. The researchers used computed-tomography scans to build digital models of the reptile's inner ear and the interior of its skull.

This technique, in turn, let the scientists put Allkaruen in its place in the pterosaur family tree. For instance, the researchers learned that some skull features associated with Pterodactylus — one genus of pterosaurs — had evolved by the early to middle Jurassic, even though pterodactyls themselves had not yet evolved.The research appears today (Aug. 30) in the open-access journal PeerJ.

Read more at Discovery News

Aug 31, 2016

How songbirds island-hopped out of Australia

This yellow-breasted satinbird (Loboparadisea sericea) is among the songbirds research shows first dispersed out of Australia about 23 million years ago through early islands in the Indonesian archipelago into Asia and subsequently the entire globe.
While it is widely accepted that songbirds originated from the Australian continent, how and when they diversified and colonized the rest of the globe has remained a mystery.

Researchers from the University of Kansas, Louisiana State University and three other institutions reconstructed the evolutionary history of songbirds using thousands of DNA sequences from majority songbird lineages and information from the fossil record to provide answers to these questions. They found that songbirds began diversifying about 33 million years ago and underwent extensive diversification in Australia. Furthermore, the researchers also found that songbirds first dispersed out of Australia about 23 million years ago through early islands in the Indonesian archipelago into Asia and subsequently the entire globe.

This new research will be published in Nature Communications on Aug. 30.

"One of the challenges with deciphering songbird evolutionary history is that they diversified so rapidly that previous studies had a difficult time estimating the branching pattern of the songbird family tree," said lead author Rob Moyle, KU professor of ecology and evolutionary biology and curator of ornithology at the KU Biodiversity Institute. "With advances in DNA sequencing technology, we were able to collect an unprecedented amount of DNA sequence data that helped clarify songbird relationships."

Songbirds comprise the largest group of birds, with about 5,000 species, accounting for nearly half of avian diversity. They are found on almost all corners of the globe, with the exception of Antarctica, and include the familiar crows and sparrows, as well as elaborate singers like mockingbirds and lyrebirds.

With a better understanding of the songbird family tree, Moyle and his colleagues were able to infer the colonization history undertaken by songbird ancestors.

The dispersal of songbirds from Australia through Indonesia, Moyle said, seems like an obvious explanation to anyone who knows world geography; but one has to bear in mind that tens of millions of years ago, world geography looked a lot different because of the Earth's constant process of plate tectonic movements. "Thirty-three million years ago, Australia was thousands of kilometers away from any continent, and New Guinea barely existed," Moyle said.

Another issue confounding our understanding of songbird evolution is the estimated age of the group, said co-lead author Carl Oliveros, a postdoctoral researcher at Louisiana State University.

"Our estimate for the age of songbirds is about half of most previous estimates, placing songbird evolution in a very different geological landscape than previously thought," said Oliveros, who earned his doctorate in ecology and evolutionary biology at KU. "Thus the previous hypothesis of long-distance dispersal by songbirds from Australia to Africa via Indian Ocean landmasses are put into question because these Indian Ocean islands were submerged by the time we think songbirds diversified."

Oliveros' and his colleagues' work also provides an alternative explanation to the high diversity of songbirds that are presently found only in New Guinea. Previous research suggested that songbirds diversified extensively in proto-islands of New Guinea before colonizing adjacent areas.

However, Oliveros and his colleagues believe that songbirds underwent extensive diversification in Australia and subsequently colonized New Guinea after the formation of the New Guinea landmass. They suggest that the aridification of Australia caused the extinction of forest-adapted songbird lineages in the continent, which left relicts of the first colonizers as sole surviving lineages in New Guinea. According to the researchers, this idea is supported by the presence of fossils in Australia of plants and mammals that are currently only found in New Guinea.

Read more at Science Daily

Fossil Find Could Boost Hunt for Ancient Mars Life

Mosiac of the Yellowknife Bay area of Gale Grater taken by the NASA Mars rover Curiosity. Scientists found strong evidence of an ancient lake and stream deposits suggesting past environmental conditions suitable for microbial life.
The discovery of fossilized microbial life that is 220 million years older than anything previously found on Earth sweetens the prospect that life may have developed on Mars as well, which was not all that different from Earth at the time.

"Earth's surface 3.7 billion years ago was a tumultuous place, bombarded by asteroids and still in its formative stages," Abigail Allwood, an astrobiologist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., wrote in a commentary published in this week's Nature.

"If life could find a foothold here, and leave such an imprint that vestiges exist even though only a minuscule sliver of metamorphic rock is all that remains from that time, then life is not a fussy, reluctant and unlikely thing. Give life half an opportunity and it'll run with it," Allwood wrote.

Allwood's essay accompanied research results , also published in Nature, from a team of Australian scientists who found evidence of life in Earth's oldest rocks, located in Greenland.

"These are not the kinds of rocks that palaeobiologists would consider a good prospect for signs of life, because they are not sedimentary like those that host most of Earth's fossil record. Rather, they are metamorphic, which means that they have been extensively deformed and altered by heat and pressure during deep burial," Allwood notes.

Allen Nutman, a researcher at the University of Wollongong in Australia, and colleagues came across what Allwood describes as "a rarity" in Greenland's Isua Greenstone Belt.

"In a small area newly revealed by snow melt, they found relatively well preserved rocks that have survived geological time with some of their original sedimentary attributes intact. In this tiny window into the deep past are subtle geochemical and textural clues to an ancient surface environment that is surprisingly familiar as a habitat for life.

"Within the rocks can be seen ancient ripple marks and piles of rock fragments deposited during an ancient storm. Combined with seawater-derived mineral chemistry, these features all point to a shallow marine, carbonate, mineral-depositing environment similar to those that have hosted abundant biota throughout Earth's history," Allwood said.

Setting back the clock for when life arose on Earth boosts the odds that Mars too had what it needed for life to take hold.

Read more at Discovery News

Fossils for Earliest Life on Earth Found

3.7 billion-year-old rock from Greenland with evidence of associated life.
Earth's oldest known fossils, dating to 3.7 billion years ago, have just been found in Greenland, according to a new study that not only reveals information about our planet, but also strengthens the possibility that Mars once harbored life.

The fossils -- microbial formations within rock revealed after a snow melt in Isua, southwest Greenland -- predate the prior earliest fossil evidence for life on Earth by 220 million years, according to the study that is published in the journal Nature.

Field discovery team at Isua, Greenland.
Since the microbial formations, known as stromatolites, indicate that communities of microbes had already formed by 3.7 billion years ago, it is likely that life on our planet began even before that very early date. Previous genetic molecular clock studies point to such a time as well.

Lead author Allen Nutman and his team further believe that there was "rapid emergence of life."

"'Rapid' stems from stromatolites being the products of communities, meaning that life had already been around for a geologically long time," Nutman, a professor of earth and environmental sciences at the University of Wollongong, explained to Discovery News.

"This places the origin of life in the Hadean (> 4 billion years), meaning that once conditions were suitable for life to appear on Earth (<4 .2="" 4.3="" a="" an="" and="" at="" been="" billion="" br="" dna="" early="" from="" geological="" have="" least="" molecules="" must="" or="" organized="" perspective="" pre-biotic="" rapid.="" rna="" stages="" the="" through="" to="" world="" years="">
Several lines of evidence indicate that the stromatolites were formed by live organisms, according to Nutman and his team, who conducted the research with funding from the Australian Research Council. The evidence is based on prior knowledge of other existing stromatolites and their tell-tale characteristics.

For example, the structures have a conical shape and internal layering. Such contrasting composition and texture in the bounds of conical formations within rock "are fairly credible hallmarks of microbial activity," Abigail Allwood, a scientist at the Jet Propulsion Laboratory at the California Institute of Technology who did not work on the new study, wrote in an accompanying Nature article. She added that this type of layering, as well as the shape and texture of the structures, means that they are not just folded rock.

Concentrations of titanium and potassium are higher in the structures than between them, providing evidence that a different type of sediment had accumulated there. This is also a characteristic associated with other stromatolites.

As for what type of microbe could have produced the stromatolites, its precise identity is unknown at this point.

"Beyond that stromatolites are microbial constructs, there is no evidence of what the culprits looked like beyond that they would have been single cellular," Nutman said, adding that he and his colleagues have already begun additional sulfur isotope testing to determine if there are signatures for metabolic (physical and chemical processes) present in the stromatolites. The results of those studies may reveal more about the likely microbes.

Read more at Discovery News

Violent Star Party for Most Distant Galaxy Cluster

A record-breaking galaxy cluster some 11.1 billion light-years away has been spotted by astronomers having the mother of all star burst parties.

Named CL J1001+0220, this cluster can be seen forming when the universe was less than three billion years old, becoming the oldest cluster of galaxies yet seen, beating the previous record holder by 700 million years.

Galactic clusters are huge; among the biggest known structures in the cosmos. They are so big that astronomers thought CL J1001 wouldn't have had the time to accumulate so many galaxies. But there it is. And it's having one heck of a star party.

"This galaxy cluster isn't just remarkable for its distance, it's also going through an amazing growth spurt unlike any we've ever seen," said astronomer Tao Wang, of the French Alternative Energies and Atomic Energy Commission (CEA), in a statement.

Deep inside that purple glow -- which is the X-ray glow of intragalactic gases observed by NASA's Chandra X-ray Observatory and European XMM-Newton space telescope -- 11 elliptical galaxies can be seen and nine of them are hothouses of stellar birth. These galaxies are creating an equivalent of 3,000 sun-like stars per year, making this cluster one of a kind.

"It appears that we have captured this galaxy cluster at a critical stage just as it has shifted from a loose collection of galaxies into a young, but fully formed galaxy cluster," said collaborator David Elbaz also from CEA.

By the researchers' reckoning, in a paper published in The Astrophysical Journal, elliptical galaxies only seem to experience this extreme starburst phase after they have accumulated gravitationally to form vast clusters like this. We are therefore having an extremely privileged view of a cluster when its inhabitants are undergoing a short yet extremely violent period of stellar activity.

The next step is to find more of these very distant and extremely active clusters in the hope of understanding more about the evolution of ancient galaxies.

From Discovery News

Cat-Sized Pterosaur Found

Artist impression of a small-bodied, Late Cretaceous azhdarchoid pterosaur from British Columbia.
Remains of a tiny, toothless pterosaur have just been identified among a collection of fossils that date to 77 million years ago, a new study reports.

The cat-sized flying reptile, which soared in the skies during the Late Cretaceous period, suggests that at least some pterosaurs were very small and lived in the same ecosystems as birds. The findings are published in the Royal Society journal Open Science.

"This new pterosaur is exciting because it suggests that small pterosaurs were present all the way until the end of the Cretaceous, and weren't outcompeted by birds," lead author Elizabeth Martin-Silverstone, a doctoral student in paleobiology at the University of Southampton, said in a press release.

"The hollow bones of pterosaurs are notoriously poorly preserved, and larger animals seem to be preferentially preserved in similarly aged Late Cretaceous ecosystems of North America," she added. "This suggests that a small pterosaur would very rarely be preserved, but not necessarily that they didn't exist."

Pterosaurs are the earliest animals with a backbone known to have evolved powered flight, and most that we know of were very large. The biggest was as large as a giraffe and had a wingspan the size of a small plane.

The newly found petite pterosaur, on the other hand, had a wingspan of only about 5 feet. Martin-Silverstone and her team identified it as an azhdarchoid pterosaur, which refers to a group of short-winged, toothless flying reptiles.

Its remains were found on Hornby Island in British Columbia in 2009 by a collector and volunteer from the Royal British Columbia Museum, who then donated them to the Museum. At the time, they were given to dinosaur expert Victoria Arbour. She, in turn, contacted Martin-Silverstone. The Museum later sent the remains to University of Portsmouth pterosaur expert Mark Witton and his team for further analysis.

A restoration of a small-bodied pterosaur, representing the atypically diminutive Late Cretaceous azhdarchoid specimen, against a modern housecat.
While the pterosaur recreated in the flesh looks like a cute character dreamed up by a movie special effects team, its remains were not in the best condition.

Read more at Discovery News

Aug 30, 2016

The rise and fall of galaxy formation

A comparison of visualizing galaxies with and without ZFOURGE.
An international team of astronomers, including Carnegie's Eric Persson, has charted the rise and fall of galaxies over 90 percent of cosmic history. Their work, which includes some of the most sensitive astronomical measurements made to date, is being published in The Astrophysical Journal.

The FourStar Galaxy Evolution Survey (ZFOURGE) has built a multicolored photo album of galaxies as they grow from their faint beginnings into mature and majestic giants. They did so by measuring distances and brightnesses for more than 70,000 galaxies spanning more than 12 billion years of cosmic time, revealing the breadth of galactic diversity.

The team assembled the colorful photo album by using a new set of filters that are sensitive to infrared light and taking images with them with the FourStar camera at Carnegie's 6.5-meter Baade Telescope at our Las Campanas Observatory in Chile. They took the images over a period of 45 nights. The team made a 3-D map by collecting light from over 70,000 galaxies, peering all the way into the distant universe, and by using this light to measure how far these galaxies are from our own Milky Way.

The deep 3-D map also revealed young galaxies that existed as early as 12.5 billion years ago (at less than 10 percent of the current universe age), only a handful of which had previously been found. This should help astronomers better understand the universe's earliest days.

"Perhaps the most surprising result is that galaxies in the young universe appear as diverse as they are today," when the universe is older and much more evolved, said lead author Caroline Straatman, a recent graduate of Leiden University. "The fact that we see young galaxies in the distant universe that have already shut down star formation is remarkable."

But it's not just about distant galaxies; the information gathered by ZFOURGE is also giving the scientists the best-yet view of what our own galaxy was like in its youth.

"Ten billion years ago, galaxies like our Milky Way were much smaller, but they were forming stars 30 times faster than they are today," said Casey Papovich of Texas A&M University.

"ZFOURGE is providing us with a highly complete and reliable census of the evolving galaxy population, and is already helping us to address questions like: How did galaxies grow with time? When did they form their stars and develop into the spectacular structures that we see in the present-day universe?" added Ryan Quadri, also of Texas A&M.

In the study's first images, the team found one of the earliest examples of a galaxy cluster, a so-called "galaxy city" made up of a dense concentration of galaxies, which formed when the universe was only three billion years old, as compared to the nearly 14 billion years it is today.

Read more at Science Daily

Traces of Prehistoric Baked Salmon Found

Salmon has been on the American menu for 11,800 years, says a new chemical investigation of prehistoric hearths.

Researchers from the University of Alaska Fairbanks (UAF) made the discovery as they excavated a total of 17 hearths from different time periods at the Upward Sun River site near the Tanana River in central Alaska.

To identify the fish remains, a team led by UAF postdoctoral researcher Kyungcheol Choy employed the same technique used to reconstruct ancient diets from cooking pottery and food residues. In this case, they analyzed the chemistry of sediments from each hearth.

"Most of archaeologists are interested in bone remains, human bones and pottery residues to reconstruct the food consumption in ancient people. However, fishbone remains are not preserved well and it's difficult to detect fish consumption in pre-pottery people," Choy told Discovery News.

The researchers examined chemical profiling of the hearth residues by carrying out stable isotope analysis and lipid residue analysis. In this way, they determined whether the food cooked there came from land animals and plants or aquatic ones.

"We confirmed the Upward Sun River site was used for cooking salmon and freshwater fish even though the site is located in the central Alaska," Choy said.

High nitrogen values in hearths indicated that fish was cooked in hearths dating to 11,800 and 11,500 years ago.

More in detail, the carbon ratios from lipids in hearths pointed to both marine and freshwater fish. Given the site location in central Alaska, far away from the ocean, the researchers concluded the marine species must have been salmon, which migrate from the ocean into rivers each year to spawn on gravel beds.

"DNA analysis of chum salmon bones from the same site on the Tanana River had previously confirmed that fish were part of the local indigenous diet as far back as 11,500 years ago," UAF said in a statement.

Read more at Discovery News

Mystery of Mars' Crater Chains Solved

Grooves on Mars' moon Phobos are likely caused by tidal forces – the mutual gravitational pull of the planet and the moon. But some of Phobos' crater chains don't line up.
Scientists have resolved a long-standing mystery of oddly aligned chains of craters on the Martian moon Phobos.

A new study shows that the peculiar chains of craters likely were created by material that had been boosted into space by a previous impact. After some time in orbit, the material crashed back into Phobos, forming chains of craters that are not aligned with surface features caused by the moon's deadly gravitational embrace with Mars.

Phobos, a small, potato-shaped moon of Mars, is covered with bulges and parallel linear features that are mostly aligned with tidal stresses as Phobos spirals closer to Mars, planetary scientists Michael Nayak and Erik Asphaug, with the University of California at Santa Cruz, write in a paper published in this week's Nature Communications.

"As the tidal bulge grows, surface stresses increase and cause striations. However, many of Phobos' linear features do not align with any interpretation of tidal stress, giving rise to alternative models," the scientists said.

They modeled the flight paths of material ejected into orbit by a primary impact strike and found that it left a chain of craters on Phobos as the process repeated.

The model was a match to one chain of craters on Phobos that had been unexplained by previous models.

Nayak and Asphaug conclude that these types of impacts likely created some of Phobos' crater chains, but that the massive tidal forces acting on Phobos also play a large role in shaping its surface features.

The scientists also noted that the lack of a crater chain near Stickney, Phobos' largest impact basin, suggests it formed when the moon was farther away from Mars.

From Discovery News

'Interesting' SETI Signal Detected: Noise or... Aliens?

The RATAN-600 radio telescope in Zelenchukskaya, Russia.
First things first, it's probably not aliens.

But astronomers have identified an "interesting" signal emanating from a not-so-distant sun-like star and the mere fact that I've mentioned aliens will have you thinking about aliens and not the other things this signal could be. I'm not saying it's aliens, OK? I really shouldn't have mentioned aliens.

Anyhow, let's wind this back a bit without mentioning ET. What's actually been detected?

Astronomers using the Russian RATAN-600 radio telescope have recorded "a strong signal in the direction of HD164595," according to Centauri Dreams' Paul Gilster who has access to a document that is currently circulating behind the scenes. The research is not published yet, but according to Gilster, the signal will be discussed during a SETI meeting at the 67th International Astronautical Congress (IAC) in Guadalajara, Mexico, in September.

The signal in question appears to be a radio burst with a frequency of 11 GHz that was detected by the observatory on May 15, 2015, coming from HD164595, which is located 95 light-years away and is known to possess one exoplanet. This exoplanet is likely "Neptune-like," approximately 4% the mass of Jupiter, with a 40 day orbit. Though this planet is very un-habitable for life as we know it (as it's very close to its star), there could be other undiscovered planets in the system.

But the interesting thing is that HD164595 is very sun-like, only a little older. The 6.3 billion year-old star is 99% the size of the sun and contains an almost identical chemical makeup. When looking for habitable worlds, it helps to find a star that has similar qualities to our sun as it's the only star known to have a planet orbiting that's packed with life.

So it becomes really interesting when a signal with few natural explanations is detected and, according to astronomer Nick Suntzeff of Texas A&M University in an interview with Ars Technica, a radio signal at this frequency is, well, "strange."

"If this were a real astronomical source, it would be rather strange," said Suntzeff, adding that his guess would be that the signal is actually terrestrial and may be a 11 GHz burst from a military source. However, there's no known program that would be using such a frequency.

The upshot is that little is so far known about this event and we'll have to wait until SETI astronomers can deduce what may have caused it. But for now, an intelligent extraterrestrial civilization blasting radio transmissions into space is a very slight possibility... though the thought is intriguing.

Gilster points out that for this to be a SETI signal, the hypothetical civilization would need to be a "Kardashev Type II civilization" if it's blasting radio in all directions (an omnidirectional radio beacon) to get cosmic attention. But if they were aiming a narrow beam signal directly at Earth, which requires far less energy, they could be a Type I civilization. As a comparison, a Type I civilization has evolved with the technological ability to harness all the energy that reached their planet from their star; a Type II civilization is much more advanced, with the ability of harnessing all of the energy from their star. In the latter case, this could be achieved using a Dyson sphere or swarm.

Read more at Discovery News

Aug 29, 2016

Strange New Objects Found During Hunt for 'Planet 9'

Astronomers have captured some interesting prey as they scan the distant solar systems for signs of a potential ninth major planet beyond Neptune.

Among the discoveries: the first Oort Cloud object that orbits entirely past Neptune. At the most distant part of its orbit, the newly found object, known as 2014 FE72, is 3,000 times farther away from the sun than Earth.

At that distance, FE72 is "likely being influenced by forces of gravity from beyond our solar system, such as other stars and the galactic tide," the Carnegie Institute for Science wrote in a press release.

Also submitted to the Minor Planet Center for official designations are the newly discovered extremely distant objects 2014 SR349 and 2013 FT28. Both so-called "trans-Neptunian objects" show signs their orbits may be under the gravitational influence of one or more large, undiscovered planets in the distant reaches of the solar system.

"The smaller objects can lead us to the much bigger planet we think exists out there," astronomer Scott Sheppard, with the Carnegie Institute for Science in Washington DC, said in a statement.

"The more we discover, the better we will be able to understand what is going on in the outer solar system," he added.

In 2014 Sheppard and colleague Chadwick Trujillo, with Northern Arizona University, discovered several extreme trans-Neptunian objects with similar orbital angles, raising the prospect that the bodies are being gravitationally influenced by an undiscovered, ninth planet more than 200 times farther away from the sun than Earth.

Calculations show the mystery planet would be at least several times bigger than Earth, and possibly as big as Neptune, which is about 17 times more massive than Earth.

So far, Sheppard and colleagues have scoured about 10 percent of the sky looking for objects beyond Neptune and the Kuiper Belt using the 6.5-meter Magellan Telescopes in Chile, NOAO's 4-meter Blanco telescope in Chile and the 8-meter Subaru telescope in Hawaii, among others.

Read more at Discovery News

'Cyclops' Beetle Grows Third Eye on Its Head

Onthophagus beetles are shown with the orthodenticle gene (left) and without it (right).
Baby beetles with three compound eyes, one in the center of their heads, are teaching scientists something about how new facial traits evolve.

The researchers focused on a group of dung beetles with horns in the genus Onthophagus. They were surprised to find that when they inactivated a certain gene, the beetle larvae developed into adults with no head horns. Instead, another compound eye popped up in an odd place.

"We were amazed that shutting down a gene could not only turn off development of horns and major regions of the head, but also turn on the development of very complex structures such as compound eyes in a new location," study leader Eduardo Zattara, a postdoctoral researcher at Indiana University's Department of Biology, said in a statement.

Like other insects, beetles hatch as larvae that then grow and metamorphose into adults. Based on research in flour beetles in the Tribolium genus, Zattara and his colleagues knew that certain genes are key to making the heads of the beetle larvae. But whether these same genes played any role in shaping adult heads was a mystery.

To find out, they figured out which parts of the larval heads turned into different parts of the adult head and then turned off some of those genes. (That research was a separate study led by Indiana University's Hannah Busey.) They found the intriguing "extra eye" results when they knocked out the so-called orthodenticle gene. Without that gene, most animal embryos don't develop a head or brain, the researchers noted.

Though beetle embryos also need orthodenticle to develop heads, nobody knew how the gene functioned in beetle larvae or adults. Turns out, during metamorphosis, the gene reorganizes the head and integrates the beetles' horns.

Shutting off orthodenticle in flour beetles did not have the same effect — they didn't grow extra eyes or lose their horns — suggesting the gene acquired this new function only in the heads of horned beetles, the researchers noted.

"Here we have a situation where a gene is already in the right place — the head — just not at the right time — the embryo instead of the adult," study researcher Armin Moczek, a biology professor at Indiana University, said in the statement. "By allowing the gene's availability to linger into later stages of development, it becomes easier to envision how it could then be eventually captured by evolution and used for a new function, such as the positioning of horns."

From Discovery News

Ancestor, Lucy, Died After Falling From Tree

Shown is a recreation of Australopithecus afarensis.
"Lucy," the iconic 3.18-million-year-old early human, literally dropped dead, according to new research that determined she died of injuries sustained after falling from a tall tree.

Since Lucy's species Australopithecus afarensis existed within a transitional period when our primate ancestors evolved from a more tree-dwelling lifestyle to a terrestrial one, the new findings -- published in the journal Nature -- indicate that adaptations that made it easier for our ancestors to walk on two legs on land compromised their ability to climb trees safely and efficiently. This may have predisposed them to falls from heights, as what may have happened to unfortunate Lucy, whose broken fossilized bones tell nearly the whole story.

"Today these fractures are often seen in automobile accidents, but also an impact following a fall from height," lead author John Kappelman, a professor of anthropology at The University of Texas at Austin, told Discovery News. "Since there were no cars in Lucy's time, we suggest that a fall is the mostly likely way that this subset of fractures formed, just as seen in modern patients today under natural conditions."

In order to assess Lucy's cause of death, Kappelman and his team studied her remains, which include parts of her skull, hand, axial skeleton, pelvis and foot. The scientists used computed tomographic scans to analyze these parts in detail, and then compared the findings to various documented clinical cases where the cause of death is clearly noted.

In addition to discovering that Lucy's cause of death is consistent with a fall from a high place -- presumed to have been from a tall tree due to where her remains were found in the Afar region of Ethiopia -- the fossil clues presented another key piece of evidence.

Fractures in Lucy's upper arms suggest that she stretched out her arms in an attempt to break her fall. This tells us that she was very much alive when she toppled to her demise, and did not die of a heart attack or from some other cause beforehand.

Lucy's distal radius (forearm bone) undergoes computed tomographic scanning.
The scientists further found that Lucy died relatively young, but was not a child, since she had all of her adult teeth, including a third molar -- a wisdom tooth.

"Her species appears to have grown up faster than us, probably more like a chimpanzee, and I suspect she was maybe 15 years old, so a young adult for her kind," Kappelman said.

Chimpanzees and other modern arboreal primates are far more agile at tree climbing than humans are. They can climb trees from a young age since it's a life or death matter for them.

But even chimps can fall to their death from trees. Famed primatologist Jane Goodall and her team documented 51 such falls in a two-year period, with breaking branches being one of the main reasons that they topple.

Lucy's feet had evolved for better walking on the ground, according to earlier research. This would have compromised her ability to clutch onto tree limbs, probably making falls more common.

Reconstruction of the foot of Lucy's species, Australopithecus afarensis, with one of the more recently found bones highlighted.
Kappelman, however, does not think that this risk caused our primate ancestors to become fully terrestrial.

He said that the arboreal lifestyle "is still a viable niche for lots of animals, including the majority of primates. The first committed terrestrial bipeds (two-legged ground walkers) are probably Homo erectus, but even some modern humans forage in the trees."

He and his colleagues suspect that small-bodied Lucy nested in trees at night to avoid predators, which is what chimps and gorillas do today. This means that, "at a minimum, she climbed up a tree at night, slept there for some hours, and climbed down from that tree in the morning," Kappelman said, adding that she might have sometimes foraged for food in trees too.

Experts contacted by Discovery News were all intrigued by the new study.

Osbjorn Pearson, an associate professor in the University of New Mexico's Department of Anthropology, said, "The evidence was literally right under the noses of many anthropologists for the last three and a half decades," referring to the time since 1982 that researchers have known of Lucy's remains.

Read more at Discovery News

Frogs Find Mates with Ultrasonic Calls in Noisy Streams

The frog Huia cavitympanum, from the island of Borneo, has evolved calls to be heard over the noise of rushing water.
Some frogs have evolved ultrasonic mating calls so they can be heard above the background rumble of the fast-flowing streams they depend on, say researchers.

Biologist Dr Sandra Goutte of Sorbonne University in Paris and her and colleagues studied the calls of a group of "torrent frogs" in Borneo, Indonesia, Malaysia, China and Cambodia.

They discovered the frogs all had higher pitched calls than most other frogs in the world, and a few species even had ultrasonic calls.

"You can see the frog calling but you cannot hear it," said Dr Goutte, who carried out the research for her PhD research.

"The call of torrent frogs has most probably been constrained by the environment they live in — which is the torrents — that are really noisy."

Male torrent frogs generally put out mating calls while sitting in vegetation next to fast-flowing streams. Females lay their eggs on rocks and then the tadpoles thrive in the oxygen-rich waters nearby.

The problem is falling water makes a low pitched rumble of about 2 kilohertz that would mask the pitch of most frog mating calls, which are generally under 5 kilohertz.

Dr Goutte and colleagues measured the call pitch of 70 species of torrent frogs, that range in size from 2 to 15 centimeters in body length.

They found that, on average, most of the frogs had calls that ranged between 4 and 10 kilohertz.

A few species had calls that consisted of frequency above 20 kilohertz, which is in the ultrasonic range, above the human range of hearing.

For example, the hole-in-the-head frog (Huia cavitympanum), which is found in Borneo, has purely ultrasonic calls.

"As a result we don't hear anything, but the frogs do," said Dr Goutte.

While the large odorous frog (Odorrana graminea), a species found in China, had partially ultrasonic calls.

"We hear only a part of the call," said Dr Goutte.

Read more at Discovery News

Dark Streaks on Mars Hold Water, But Not Much

The dark streaks are called recurring slope lineae (RSL), and last year, scientists presented new evidence suggesting that these streaks contain liquid water — albeit very, very salty water called brine. The new work shows that these RSL cannot contain more water than the driest deserts on Earth, which makes it unlikely that water is streaming down these hillsides.

In an attempt to determine the water content of the RSL, researchers turned to Mars Odyssey's Thermal Emission Imaging System (THEMIS), and looked at the temperature of the planet's surface from orbit.

"When water is present in the spaces between particles of soil or grains of sand, it affects how quickly a patch of ground heats up during the day and cools off at night," NASA officials said in a statement. The depth to which the water saturates the soil also influences how quickly the surface changes temperature, according to NASA.

The researchers studied the RSL on the walls of craters within the Valles Marineris canyon on Mars. They looked at several years' worth of surface-temperature measurements by THEMIS, to figure out the water concentration in the soil.

The researchers found that the upper limit of the water content was about 3 percent by weight — about the same concentration of water as in the surface material of the Atacama Desert in Chile and the Antarctic Dry Valleys, which are two of the driest places in the world.

The findings presented in 2015 showed evidence of "hydrated salts" (or brines) at the surface where the dark streaks are located.

"Our findings are consistent with the presence of hydrated salts, because you can have hydrated salt without having enough for the water to start filling pore spaces between particles," said Christopher Edwards, a faculty member in the Department of Physics and Astronomy at Northern Arizona University and one of the study's authors. "Salts can become hydrated by pulling water vapor from the atmosphere, with no need for an underground source of the water."

Read more at Discovery News