Birds That Crash Into Cars Tend to Have Teeny Brains

What's the difference between birds that get killed by cars, and those that don't?

The dead ones tend to have smaller brains, scientists who performed 3,521 avian autopsies said Wednesday.

What might be called the "bird brain rule" applies to different species, depending on the ratio of grey matter to body mass, they reported in the journal Royal Society Open Science.

Crows, for example, have big brains relative to their size, and have shown a remarkable knack for navigating oncoming traffic.

While picking at road kill on Florida highways, earlier research showed, the scavengers learned to ignore cars and trucks whizzing by them within inches, but would fly away just in time when threatened by a vehicle in their lane.

"I don't know if we can say they are 'smarter,' but they do exhibit cognitive behaviour that makes them likely to survive," lead author Anders Pape Moller, an evolutionary biologist at the French National Center for Scientific Research, told AFP.

Pigeons, by contrast, appear to be less adept at avoiding collisions, a deficiency visible in compressed form on most big-city streets.

Not coincidentally, they have teeny-weeny brains.

More surprisingly, the relation between brain size and traffic accidents also holds within the same species, the study found.

"Common European blackbirds, house sparrows and robins all show this difference in individuals that were hit by cars, and those that were not," Moller said by phone.

Undamaged brains from birds killed in accidents - weighed to within a hundredth of a gram - were consistently smaller, he said.

Grim tally
 
In total, the researchers examined 251 different species.

The finding raises the question of whether certain species, and certain populations within species, have evolved over the space of dozens of generations such that birds with car-dodging abilities have become more common.

Moller is skeptical.

Recent research has shown that evolutionary changes in many animals - fish and insects, in particular - are occurring in response to climate change and human encroachment on habitat far more quickly that scientists imagined possible.

But given that fast-moving cars have only been on the roads for less than a century, it is unlikely that birds have adapted - as a species level - that fast.

"The other problem is that total mortality due to traffic is not big enough to cause evolutionary change," Moller said.

It would take a very high death toll, in other words, to exert a strong influence on the course of evolution.

Having said that, a lot of birds get killed by moving vehicles.

The State of the Birds annual report estimated in 2014 that 200 million birds perish on the road every year in the United States alone.

Estimates for Europe are lower, but worldwide the grim tally is certainly in the hundreds of millions.

Read more at Discovery News

Rare ‘Coffin Birth' Found in Black Death Burial Site

Researchers investigating a 14th century burial ground have identified a rare case of "coffin birth" - a gruesome phenomenon in which a deceased pregnant woman's fetus is expelled within the grave.

The event, which has seldom been reported in archaeology, is known as postmortem fetal extrusion. It results from a build-up of gas pressure within the decomposing body.

"In this case, we have a partial expulsion of a 38- to 40-week-old fetus, which was found to be complete and to lie within the birth canal," Deneb Cesana, at the University of Genova, told Seeker.

The remains of the woman and her unborn baby were originally uncovered in 2006, interred with two other young individuals that scientists say were aged 12 and three years old. Only recently has the discovery been fully investigated.

The research was led by Cesana and her colleagues Ole Jørgen Benedictow, a plague historian at the University of Oslo, and Raffaella Bianucci, a bioanthropologist at the University of Warwick in England. Their work appears in the journal Anthropological Science.

The gravesite was found in the cemetery of the "ospitale" (hostel) of San Nicolao di Pietra Colice, located some 45 miles from Genova.

The hostel, which also housed a church, was situated in the Northern Apennines at about 2,600 feet above sea level, and was used as a resting place by travelers and pilgrims heading to Rome and trekking along the two major transit routes of the Liguria region.

"The woman was found laying slightly on her side, while on her left there were two young individuals of unknown sex," said archaeologist Fabrizio Benente, of the University of Genova.

Benente, who was not involved in the anthropological study, directed the excavation campaign with a team of the International Institute of Ligurian Studies and the University of Genova.

"This was the only multiple burial found at the cemetery," he said. "The others were all single graves."

He added that the corpses had been buried simultaneously and directly into the soil, and dated the burial to the second half of the 14th century.

The timing corresponded to the arrival of the Black Death in Genoa in 1348. The researchers hypothesized that the woman and the two children likely died of the bubonic plague.

Bianucci's analysis confirmed that three of the four individuals - the woman, the fetus, and the 12-year-old child - tested positive for the F1 antigen of Yersinia pestis, the bacterium that causes the plague.

"This is the first evidence of Y. pestis infection in 14th-century Liguria," Bianucci said.

"Our finding supports the notion that the contagion, which had originally started from Genoa's port area, progressively spread and disseminated through the main communication routes," she added.

Anthropological investigations carried out and funded by the Archaeological Museum of Sestri Levante and the Archaeological Superintendency of Liguria showed that the woman, who was about 5 feet 11 inches tall, was between 30 and 39 years old when she died.

It emerged that she had several ailments during her life. Her teeth revealed localized periodontitis and linear enamel hypoplasia - a band-like dental defect that denotes childhood physiological stress - while her bones showed evidence of other diseases.

Read more at Discovery News

Life Outside Our Solar System Might Exist on Exomoons

As some scientists search for habitable planets outside our solar system, other researchers are tackling a similar question for the moons of these planets. So-called exomoons have yet to be found outside our solar system, and a detection could be a decade away - or more.

But scientists, writing in a new research paper, theorize a Mars-sized exomoon of a gas giant planet and ask whether or not liquid water could be found on its surface.

In our own solar system, the closest analog is Jupiter's Ganymede, the biggest moon in the solar system and about five-sixth the size of Mars.

NASA confirmed in 2015 the presence of a liquid ocean on Ganymede after performing Hubble Space Telescope observations of the moon's auroras, which appear to rock back and forth less than expected with Jupiter's magnetic field. The space agency said the attenuation is likely due to a salty ocean under Ganymede's surface.

As for this theoretical Mars-sized exomoon, the picture is murky. The scientists considered energy sources such as stellar radiation (which changes as a function of distance to the star), the stellar reflected light from a Jupiter-sized planet on the moon, the planet's own thermal emission on the moon, and the tidal heating inside the moon that is generated due to the changing gravitational pull of the planet. (This tidal heating would be most pronounced if the moon had an eccentric orbit, like the volcanic moon Io has around Jupiter.)

It's know that tidal heating rates decrease if a moon is molten inside, because lava creates an inherent negative feedback mechanism where the heating sort of switches off, and the moon cools down inside. This is called the "tidal thermostat effect," co-author of the paper Rene Heller said in an email. Heller is an astrophysicist at the Max Planck Institute for Solar System Research in Germany.

"We investigate, for the first time, the interplay of all the possible exomoon heat sources as a function of various distances from the host star," he added. "Actually, we even consider two possible types of host stars: a sun-like star, and a red dwarf star (an M dwarf)."

For a sun-like star, the authors found that any moon around a gas giant beyond three astronomical units, or three Earth-sun distances, would have a high enough energy flux to stop the tidal thermostat effect from happening. But if the moon is volatile enough, it could have global volcanism - just like what we see on Io.

Heller described this situation as "dangerous" for organisms.

"They might have lots of liquid surface water, but their surfaces could at the same time be blotched with devastating volcanoes," he wrote. "Nevertheless, we illustrate that they could be habitable given the right amount of tidal heating, and we show at which distances to their planets these moons would need to be."

M-dwarfs are a common target for exoplanet searches because they are smaller and dimmer, making it easier to see planets passing across their surfaces, or the effect of planets tugging on the star itself. But for exomoons, it's even less clear how habitable they would be in such a system. "Moons cannot be stable in the very inner regions of the stellar habitable zone," Heller said.

The best examples for tidally heated bodies in our own solar system are all moons: Jupiter's Io and Europa, as well as Saturn's Enceladus. While Europa and Enceladus are strongly suspected to have oceans underneath an icy surface, Heller pointed out his research is more focused on habitability on the surface of the moon. A better analog, he said, might be Saturn's moon Titan - but with a much warmer surface. Titan has a thick orange atmosphere, as well as liquid hydrocarbon lakes.

"Due to observational selection effects, which will prefer big moons around low-mass planets, I think the first exomoon will be unlike anything we know from the solar system," Heller said.

Read more at Discovery News

Time-Travel Gaze Reveals the Shape of Ancient Galaxies

Astronomers are seeing what Earth's own galaxy looked like in its youth by scanning the skies for some of the oldest objects in the universe.

Using the Atacama Large Millimeter/submillimeter Array (ALMA), a large radio observatory in Chile, researchers have taken "baby pictures" of Milky Way-like galaxies when their star formation was just beginning to accelerate. At that time, the universe was nearly two billion years old. Since light moves at a finite speed, looking deep into the universe also means looking back in time, and these young galaxies are about 12 billion light-years away from Earth. The cosmos itself is about 13.8 billion years old.

Looking at two of the ancient galaxies in infrared wavelengths, the researchers saw that very early in the galaxies' development, they had what look like extended discs of hydrogen gas that far outpaced the smaller, star-forming regions within. These galaxies also already had rotating discs of gas and dust, and were forming stars at a relatively rapid pace: up to 100 solar masses (the mass of Earth's sun) per year.

Officially designated ALMA J081740.86+135138.2 and ALMA J120110.26+211756.2, the galaxies were observed using light from two quasars in the background. Quasars are supermassive black holes surrounded by bright accretion discs, and are themselves thought to be the centers of particularly active galaxies.

Composite ALMA and optical image of a young Milky Way-like galaxy 12 billion light-years away and a background quasar 12.5 billion light-years away.

Usually, seeing ordinary galaxies when they are in front of a quasar is difficult, because quasars are blazingly bright and a young galaxy is relatively faint, the researchers said in a statement. But using ALMA, the astronomers were able to see the infrared light from the galaxies' ionized carbon shining on its own, and also hydrogen silhouetted in the shine of the quasars. The carbon, which emits light at a wavelength of 158 micrometers (the far infrared), marked the structure of each galaxy, while emissions of infrared light from dust showed regions where stars were being born, according to the study.

The glowing carbon also offered another clue to the galaxies' structure, because its position was offset from the hydrogen gases that the astronomers initially saw, as revealed by the quasars' shine. That means that the galaxies' gases extend far from the dense carbon regions, suggesting each galaxy has a large halo of hydrogen encircling it, the researchers said.

Looking at the foreground objects that a shining background quasar could reveal, "we had expected we would see faint emissions right on top of the quasar, and instead we saw bright galaxies at large separations from the quasar," J. Xavier Prochaska, an astrophysicist at the University of California, Santa Cruz, and co-author on the new study, said in a statement.

The data also showed that the young galaxies have already begun rotating, which is a hallmark of spiral galaxies like the Milky Way, the study said.

The effort to find such early stage galaxies began in 2003, when Prochaska first worked on the idea of using the spectra of quasars, the wavelengths of light they emit, to reveal those of galaxies in the foreground. Such arrangements are called damped Lyman-alpha systems, because the hydrogen gas blocks certain wavelengths of light from the quasar, revealing the gas's presence and extent.

Read more at Discovery News

New Dinosaur ‘Horner’s Frightful Lizard’ Changes the Face of Tyrannosaurs

Recreation of the face of Horner’s Frightful Lizard (Daspletosaurus horneri).

T. rex and other tyrannosaurs are getting a facial makeover, thanks to new research on a recently discovered carnivorous dinosaur that measured around 30 feet long and sported a scaly, lipless face with a highly touch-sensitive snout.

In addition to revealing greater detail of what the faces of tyrannosaurs looked like, the new dinosaur — called Horner’s Frightful Lizard (Daspletosaurus horneri) — helps to solve many other animal-related mysteries, such as why tyrannosaurs tended to have small arms, why today’s birds lack lips, and why alligators and crocodiles possess such sensitive snouts.

The findings are published in the journal Scientific Reports.

“We hypothesize that tyrannosaurs, including D. horneri and T. rex, had a tactile sensory system that was comparable, if not identical, to what is seen in living crocodylians,” lead author Thomas Carr, a vertebrate paleontologist at Carthage College, told Seeker, referring to an order of species that includes alligators, crocodiles, caimans, and the gharial.

“Work done by biologists on crocodylians has found that their faces were extremely sensitive to touch, rivaling that of human fingertips,” he continued. “The sensitivity comes from a combination of multiple branches of the trigeminal nerve that innervate the skin at specialized structures of thin, dome-like coverings of skin where neurons are in high concentration.”

Carr and his team made this determination after studying the new dinosaur’s well-preserved remains, which were unearthed at a site called the Two Medicine Formation in Montana. The remains include the skull and skeleton of a juvenile, the skull and skeleton of an adult, as well as other fossils from the species, which lived 75.1 to 74.4 million years ago.

The massive field jackets containing the bones of the adult specimen of Daspletosaurus horneri were hauled out by a mule-drawn sled at the Two Medicine Formation site in Montana.

The dinosaur was named D. horneri after the renowned paleontologist John “Jack” R. Horner, a former curator of the Museum of the Rockies in Bozeman, Montana.

The researchers conducted work that co-author Jayc Sedlmayr of the Louisiana State University Health Sciences Center New Orleans described as “arm deep in blood and guts,” dissecting birds, alligators, and crocodiles to see how facial nerves and arteries leave traces on bones. The scientists then used this information to flesh out the face of Horner’s Frightful Lizard that included small horns above the eyes.

The dinosaur’s super-sensitive snout likely would have been important “for prey manipulation, feeding, and for reproduction, such as building a nest, manipulating eggs, and safely moving hatchlings,” co-author David Varricchio, a professor at Montana State University, told Seeker.

He added that the snout could therefore function like an arm, given that “the small arms of tyrannosaurs were likely not effective at any of these tasks.”

The tender snout also appears likely to have served a sensual purpose when it came to mating.

“In courtship, tyrannosaurids might have rubbed their sensitive faces together as a vital part of pre-copulatory play,” says the report.

Horner’s Frightful Lizard used its snout skills to help devour prey that included horned, crested duckbill and dome-headed dinosaurs, in addition to much smaller carnivorous dinos, the researchers believe.

Carr said that “killing would have been the work of the jaws,” with their sensitive margins likely giving the hunter “important information regarding how hard to bite, whether or not the prey was still living, and the locations of soft and hard parts.”

The dinosaur’s similarities with today’s crocodiles and alligators are evidence of a genetic inheritance from a shared ancestor.

“Crocodylians are not dinosaurs, and dinosaurs are not crocodylians," Carr clarified, "but they do share a common ancestor.”

Birds, on the other hand, are considered to be living dinosaurs. Birds probably inherited their lack of lips from their equally lipless dino ancestors, according to the scientists.

The researchers further believe that Horner’s Frightful Lizard evolved via a rare form of speciation known as anagenesis, where one species gradually morphs into a new one over time.

Co-author Jason Moore of the University of New Mexico explained that he most common form of speciation, known as cladogenesis, “most frequently occurs by a small population of one species being separated from the remainder of the members of that species and being subject to a different set of environmental conditions, and hence evolving different sets of traits."

Read more at Discovery News

Climate Change Incited Wars Among the Classic Maya

Reconstruction of Bonampak frescos, 9th century AD.

Does a warming world beget more wars? A new study that investigates the relationship between climate change and clashes among the Classic Maya believes so, drawing an explicit link between temperature increases and growing conflicts.

The study, published in Quaternary Science Reviews, examined about 500 years of Maya history, from 363 to 888 AD.

This is the so-called Classic period in which the Mesoamerican civilization boomed, with its people constructing extensive cities and massive pyramids, as well as developing one of the earliest writing systems in the Americas.

Indeed, the Maya began a tradition of recording historical events on stone monuments.

“The inscriptions that have been translated provide often remarkably detailed accounts of myths and political events, including conflicts between city-states,” said the report, which was authored by Mark Collard, Canada research chair at Simon Fraser University in British Columbia and professor of archaeology at the University of Aberdeen in Scotland, along with Christopher Carleton and David Campbell, both of Simon Fraser University.

The researchers cataloged inscriptions on monuments related to violent struggles and compiled temperature and rainfall records for the regions inhabited during the Classic period: the lowlands of the Yucatán Peninsula, which includes parts of southern Mexico, Guatemala, and Belize.

A total of 144 unique conflicts emerged from inscriptions on monuments from more than 30 major Maya centers. The research team then compared conflict records to palaeoclimate data, and the correspondence was impressive.

“The change in conflict levels between 350 and 900 AD was considerable,” they wrote. “The number of conflicts increased from 0 to 3 every 25 years in the first two centuries to 24 conflicts every 25 years near the end of the period.”

Polychrome vase decorated with eleven figures involved in battle. Late Classic Maya period, 600 900 AD.

They noted the exacerbation of conflicts could not be explained by change in the amount of rainfall. It was instead associated with an increase in summer temperature.

“There's been quite a bit of discussion about the impact of climate change on the Classic Maya, but this discussion has focused on drought,” Collard told Seeker. “Our study suggests that we've been looking in the wrong place and that the impact of temperature needs to be looked at more closely.”

Experts think that there are two potential mechanisms by which increases in temperature can lead to greater conflict.

One is psychological — when temperatures rise, tempers shorten. Several studies suggest it is possible that increased average summer temperatures made the Classic Maya more bellicose.

The other mechanism, which Collard and his colleagues find more likely and compelling, is economic, and involves the staple crop for the Classic Maya: maize.

Throughout the Classic period, average temperature fluctuated between 82.4 degrees Fahrenheit (28 degrees Celsius) and 84.2°F (29°C). During periods when the temperature was around 82.4°F (28°C) or less, maize yields were reasonably stable, with little or no food shortage and little conflict.

But as temperature continued to rise and the region experienced days at or above 86°F (30°C), crop shortfalls occurred frequently. Large-scale deforestation throughout the Classic period caused by urban expansion worsened the effect, increasing regional temperatures by reducing soil moisture availability.
The result was food shortage, which led to spiking levels of conflict.

“We had originally thought that it all came down to starvation, but after talking with Maya specialists, we decided that wasn't convincing,” Collard said.

He explained that maize would have been difficult to transport, in which case the idea of attacking neighbors for food did not seem very likely.

“Instead, it's probably better to consider the increase in warfare in a way that we often think about warfare today — namely as a tool for the elite to maintain support,” Collard said.

With declining maize yields, a ruler could not have relied on opulent festivals or fed large labor forces needed to build impressive monuments. Consequently, going to war more often would have been an effective tactic to maintain status, prestige, and power.

“I think of it as being similar to the way that some modern political leaders seem to use conflict with neighbors to distract from problems within their country,” Collard said.

Eventually, the growth in conflict became explosive.

The researchers believe the findings have implications for the debate about contemporary climate change. Concern is growing that climate change effects would increase violence within and between human societies.

The Intergovernmental Panel on Climate Change has cautioned that climate change will exacerbate conflict at a range of scales, from inter-personal violence to civil war, while the US Department of Defense has classified climate change as a threat multiplier, suggesting that it could lead to political and social unrest and increased terrorism.

“Our study shows that small year-to-year changes in climate can result in large, negative effects over the long term,” Collard said. “This is a problem for us, humans, because most of us are oriented towards the short term.”

“We run the risk of ignoring changes that will affect our children and grandchildren, because we can't perceive those changes,” he added.

Read more at Discovery News

Solar wind stripped Martian atmosphere away

An illustration of the MAVEN spacecraft.

Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN (Mars Atmosphere and Volatile Evolution Mission) spacecraft led by the University of Colorado Boulder.

"We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, principal investigator for MAVEN and a professor at the Laboratory for Atmospheric and Space Physics (LASP). "The team made this determination from the latest result, which reveals that about 65 percent of the argon that was ever in the atmosphere has been lost to space."

Jakosky is lead author of a paper on this research to be published in Science on Friday. Marek Slipski, a LASP graduate student, co-authored the study.

MAVEN team members had previously announced measurements showing that atmospheric gas was being lost to space and that described the processes by which atmosphere was being stripped away. The present analysis uses measurements of today's atmosphere to give the first estimate of how much gas has been removed through time.

Liquid water, essential for life, is not stable on Mars' surface today because the atmosphere is too cold and thin to support it. However, evidence such as features resembling dry riverbeds and minerals that only form in the presence of liquid water indicates the ancient Martian climate was much different -- warm enough for water to flow on the surface for extended periods.

There are many ways a planet can lose some of its atmosphere. For example, chemical reactions can lock gas away in surface rocks or an atmosphere can be eroded by radiation and wind from the planet's parent star. The new result reveals that solar wind and radiation were responsible for most of the atmospheric loss on Mars and that the depletion was enough to transform the Martian climate. The solar wind is a thin stream of electrically conducting gas constantly blowing from the surface of the sun.

Young stars have far more intense ultraviolet radiation and winds, so atmospheric loss by these processes was likely much greater early in Mars' history, and these processes may have been the dominant ones controlling the planet's climate and habitability, according to the team. It's possible that microbial life could have existed at the surface early in Mars' history. As the planet cooled off and dried up, any life could have been driven underground or forced into occasional or rare surface oases.

Jakosky and his team got the result by measuring the atmospheric abundance of two different isotopes of argon gas. Isotopes are atoms of the same element with different masses. Because the lighter of the two isotopes escapes to space more readily, it will leave the gas remaining behind enriched in the heavier isotope. The team used this enrichment together with how it varied with altitude in the atmosphere to estimate what fraction of the atmospheric gas has been lost to space.

As a "noble gas" argon cannot react chemically with anything so it won't get sequestered in rocks, and the only process that can remove it to space is a physical process called "sputtering" by the solar wind. In sputtering, ions picked up by the solar wind impact Mars at high speeds and physically knock atmospheric gas into space. The team tracked argon because it can be removed only by sputtering. Once they determined the amount of argon lost by sputtering, they could use the efficiency of sputtering to determine the sputtering loss of other atoms and molecules, including carbon dioxide (CO2).

CO2 is of interest because it is the major constituent of Mars' atmosphere and because it's an efficient greenhouse gas that can retain heat and warm the planet.

"We determined that the majority of the planet's CO2 also has been lost to space by sputtering," said Jakosky. "There are other processes that can remove CO2, so this gives the minimum amount of CO2 that's been lost to space."

The team made its estimate using data on the Martian upper atmosphere from MAVEN's Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument supported by measurements from the Martian surface made by NASA's Sample Analysis at Mars (SAM) instrument on board the Curiosity rover.

"The combined measurements enable a better determination of how much Martian argon has been lost to space over billions of years," said Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Maryland. Mahaffy, a co-author of the paper, is principal investigator on the SAM instrument and lead on the NGIMS instrument, both of which were developed at NASA Goddard.

Read more at Science Daily

A decorated raven bone discovered in Crimea may provide insight into Neanderthal cognition

Legend of the image: left: notched raven bone from Zaskalnaya VI Neanderthal site, Crimea. center: experimental notching of a bird bone; right: sequences of experimentally made notches compared to those from Zaskalnaya VI.

The cognitive abilities of Neanderthals are debated, but a raven bone fragment found at the Zaskalnaya VI (ZSK) site in Crimea features two notches that may have been made by Neanderthals intentionally to display a visually consistent pattern, according to a study by Ana Majkic at the Universite de Bordeaux and colleagues, published in the open access journal, PLOS ONE on March 29, 2017.

Majkic and colleagues conducted a mixed-methods study to assess whether the two extra notches on the ZSK raven bone were made by Neanderthals with the intention of making the final series of notches appear to be evenly spaced. First, researchers conducted a multi-phase experiment where recruited volunteers were asked to create evenly spaced notches in domestic turkey bones, which are similar in size to the ZSK raven bone. Morphometric analyses reveal that the equal spacing of the experimental notches was comparable to the spacing of notches in the ZSK raven bone, even when adjusted for errors in human perception. Archeological specimens featuring aligned notches from different sites were also analyzed and compared with the ZSK raven bone specimen.

Researchers concluded that the two extra notches on the ZSK raven bone may have been made by Neanderthals intentionally to create a visually consistent, and perhaps symbolic, pattern.

A series of recent discoveries of altered bird bones across Neanderthal sites has caused many researchers to argue that the objects were used for personal ornaments, as opposed to butchery tools or activities. But this study is the first that provides direct evidence to support a symbolic argument for intentional modifications on a bird bone.

From Science Daily

Mysterious cosmic explosion surprises astronomers studying the distant x-ray universe

X-ray image of the Chandra Deep Field-South, the region of the sky where the flaring X-ray source was discovered. This is the deepest X-ray image ever created, made with about 7 million seconds of observing time with NASA's Chandra X-ray Observatory. The location of the flaring source, named 'CDF-S XT1,' is marked with the white arrow. The series of small images along the bottom show the variability of the flaring X-ray source over time (with time increasing from left to right, spanning a period of a few hours).

A mysterious flash of X-rays has been discovered by NASA's Chandra X-ray Observatory in the deepest X-ray image ever obtained. This source likely comes from some sort of destructive event, but it may be of a variety that scientists have never seen before.

The X-ray source was originally discovered in October 2014 by Bin Luo, a Penn State postdoctoral researcher; Niel Brandt, the Verne M. Willaman Professor of Astronomy and Astrophysics and professor of physics at Penn State; and Franz Bauer, an associate professor of astrophysics at the Pontifical Catholic University of Chile in Santiago, Chile. Luo has since moved from Brandt's group to become a professor of astronomy and space science at Nanjing University in China, and Bauer had been a postdoctoral researcher in Brandt's group from 2000 to 2003. The data were gathered using the Advanced CCD Imaging Spectrometer on Chandra, an instrument conceived and designed by a team led by Penn State Evan Pugh Professor Emeritus of Astronomy and Astrophysics Gordon Garmire.

"This flaring source was a wonderful surprise bonus that we accidentally discovered in our efforts to explore the poorly understood realm of the ultra-faint X-ray universe," said Brandt. "We definitely `lucked out' with this find and now have an exciting new transient phenomenon to explore in future years."

Located in a region of the sky known as the Chandra Deep Field-South (CDF-S), the X-ray source has remarkable properties. Prior to October 2014, this source was not detected in X-rays, but then it erupted and became at least a factor of 1,000 brighter in a few hours. After about a day, the source had faded completely below the sensitivity of Chandra.

Thousands of hours of legacy data from the Hubble and Spitzer Space Telescopes helped determine that the event came from a faint, small galaxy about 10.7 billion light years from Earth. For a few minutes, the X-ray source produced a thousand times more energy than all the stars in this galaxy.

"Ever since discovering this source, we've been struggling to understand its origin," said Bauer. "It's like we have a jigsaw puzzle but we don't have all of the pieces."

Two of the three main possibilities to explain the X-ray source invoke gamma-ray burst (GRB) events. GRBs are jetted explosions triggered either by the collapse of a massive star or by the merger of a neutron star with another neutron star or a black hole. If the jet is pointing towards the Earth, a burst of gamma-rays is detected. As the jet expands, it loses energy and produces weaker, more isotropic radiation at X-ray and other wavelengths.

Possible explanations for the CDF-S X-ray source, according to the researchers, are a GRB that is not pointed toward Earth, or a GRB that lies beyond the small galaxy. A third possibility is that a medium-sized black hole shredded a white dwarf star.

"None of these ideas fits the data perfectly," said co-author Ezequiel Treister, also of the Pontifical Catholic University, "but then again, we've rarely if ever seen any of the proposed possibilities in actual data, so we don't understand them well at all."

The mysterious X-ray source was not seen during the two-and-a-half months of exposure time Chandra has observed the CDF-S region, which has been spread out over the past 17 years. Moreover, no similar events have yet to be found in Chandra observations of other parts of the sky.

This X-ray source in the CDF-S has different properties from the as yet unexplained variable X-ray sources discovered in the elliptical galaxies NGC 5128 and NGC 4636 by Jimmy Irwin of the University of Alabama and collaboratorsUniversity of Alabama and collaborators. In particular, the CDF-S source is likely associated with the complete destruction of a neutron star or white dwarf, and is roughly 100,000 times more luminous in X-rays. It is also located in a much smaller and younger host galaxy, and is only detected during a single, several-hour burst.

"We may have observed a completely new type of cataclysmic event," said co-author Kevin Schawinski, of ETH Zurich in Switzerland. "Whatever it is, a lot more observations are needed to work out what we're seeing."

Additional highly targeted searches through the Chandra archive and those of ESA's XMM-Newton and NASA's Swift satellite may uncover more examples of this type of variable object that have until now gone unnoticed. Future X-ray observations by Chandra and other X-ray observatories such as the planned Chinese Einstein Probe also may reveal the same phenomenon from other objects.

Read more at Science Daily

This timid little fish escapes predators by injecting them with opioid-laced venom

This image shows the skull of the venomous species Meiacanthus grammistes.

Fang blennies are small fish with big teeth. Specifically, they have two large canine teeth that jut out of their lower jaw. Since blenny fish are only about two inches long, these "fangs" would be less than intimidating if not for the venom within. Blenny fish venom most likely causes a sudden drop in blood pressure in would-be predators, such as grouper fish, that have been bitten by blennies, researchers report on March 30 in Current Biology.

When the researchers did a proteomic analysis of extracted fang blenny venom, they found three venom components -- a neuropeptide that occurs in cone snail venom, a lipase similar to one from scorpions, and an opioid peptide. And, surprisingly, when they injected the blenny venom into lab mice, the mice didn't show any signs of pain.

"For the fang blenny venom to be painless in mice was quite a surprise," says study co-author Bryan Fry of University of Queensland. "Fish with venomous dorsal spines produce immediate and blinding pain. The most pain I've ever been in other than the time I broke my back was from a stingray envenomation. 'Sting'ray sounds so benign. They don't sting. They are pure hell."

Fang blenny venom, however, seems to have a very different effect on its victims. Since the researchers used rodents for the pain test, they can't entirely rule out the possibility of blenny venom causing pain in fish, but it seems plausible that the neuropeptide and opioid components may cause a sudden drop in blood pressure, most likely leaving the blenny's attacker disorientated and unable to give chase. "By slowing down potential predators, the fang blennies have a chance to escape," says Fry. "While the feeling of pain is not produced, opioids can produce sensations of extremely unpleasant nausea and dizziness [in mammals]."

Extracting the tiny fish's venom for chemical tests was no easy feat. When blenny fish bite an attacker, they only inject a tiny amount of venom, making it extremely difficult to collect enough for proteomic analyses. The researchers ended up using a quirky but labor-intensive method for extracting blenny venom: they would pluck the little fish out of their tanks, dangle a cotton swab in front of them so that the blenny would bite the cotton swab, and then suspended the cotton swabs in a solution that drew out the venom (after putting the fish back in the tank).

Nonvenomous fang blennies and other small fish capitalize on the venom's success by mimicking venomous fang blennies' colors and patterns. "Predatory fish will not eat those fishes because they think they are venomous and going to cause them harm, but this protection provided also allows some of these mimics to get very close to unsuspecting fish to feed on them, by picking on their scales as a micropredator," says study co-author Nicholas Casewell of the Liverpool School of Tropical Medicine. "All of this mimicry, all of these interactions at the community level, ultimately are stimulated by the venom system that some of these fish have."

Another surprise from the study was the evidence suggesting that fang blenny fangs evolved before the venom. "This is pretty unusual, because often what we've found -- for example, in snakes -- is that some sort of venom secretions evolved first, before the elaborate venom delivery mechanism evolved," says Casewell. Evolution favored the tiny fish with large teeth first and later found a way to enhance them with venom.

"These unassuming little fish have a really quite advanced venom system, and that venom system has a major impact on fishes and other animals in its community," says Casewell.

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