Aug 22, 2015

Solving mysteries of the interstellar medium

It is one of the most intriguing questions in astrochemistry: the mystery of the diffuse interstellar bands (DIBs), a collection of about 400 absorption bands that show up in spectra of light that reaches the earth after having traversed the interstellar medium. Despite intense research efforts over the last few decades, an assignment of the DIBs has remained elusive, although indications exist that they may arise from the presence of large hydrocarbon molecules in interstellar space. Recent experiments at the Max Born Institute lend novel credibility to this hypothesis.

Among the hydrocarbons that are possible carriers of the DIBs, polycyclic aromatic hydrocarbons (PAHs) are considered to be particularly promising. The presence of PAH molecules was previously inferred in many astronomical objects, as well as in the interstellar medium of the Milky Way. However, within the astronomical community, the linewidths of the DIBs, which are indicative of the lifetimes of the excited states that are involved in the absorption process, are often considered as an argument that speaks against the PAHs. The new experiment was performed in collaboration with scientists from the university of Lyon and aided by theoretical input from scientists at the universities of Heidelberg, Hyderabad and Leiden. It has been shown that the lifetimes of excited states of small to medium-size PAHs are consistent with the linewidths that are observed for the DIBs.

In the experiments, a series of small to medium-size PAH molecules (naphthalene, anthracene, pyrene and tetracene, containing 2-4 benzene-like aromatic rings), were ionized by an ultrashort extreme-ultraviolet (XUV) laser pulse. As a result of electron correlation, the absorption of an XUV photon not only led to removal of one of the electrons, but furthermore to electronic excitation of the molecular ion left behind. The lifetimes of these excited cationic electronic states were monitored by probing the ions with a moderately strong, time-delayed infrared (IR) laser pulse. When the ions are formed, the electronic excitation is at its highest, and only one or a few IR photons are needed to remove a second electron. However, a little later, when the ion relaxes and energy is transferred from the electronic to the vibrational degrees of freedom, more IR photons are needed to remove the second electron. In other words, monitoring the formation of doubly-charged ions as a function of the time delay between the XUV and IR laser pulses allowed extraction of the lifetimes of the states formed by the XUV ionization process. As it turned out, and as was further supported by high-level calculations, these lifetimes of a few 10s of femtoseconds are well within the range of what is required for potential carriers of the DIBs.

Read more at Science Daily

A detector shines in search for dark matter

Results of the XENON100 experiment are a bright spot in the search for dark matter.

The team of international scientists involved in the project demonstrated the sensitivity of their detector and recorded results that challenge several dark matter models and a longstanding claim of dark matter detection. Papers detailing the results will be published in upcoming issues of the journals Science and Physical Review Letters.

Dark matter is an abundant but unseen matter in the universe considered responsible for the gravitational force that keeps the Milky Way galaxy together, said Rafael Lang, an assistant professor of physics at Purdue University who was involved in the research.

"Our galaxy spins like an incredibly fast merry-go-round, and the stars, planets and other objects would go flying off in different directions if it wasn't for gravitational pull," he said. "When we calculate the gravity of every known mass, it is nowhere near enough force to keep the galaxy together. Dark matter is the stuff that makes up the difference."

Although the team did not detect dark matter, the capabilities demonstrated by the XENON100 detector are encouraging. The high sensitivity shown in the experimental results could free the international research team from the need to constrain analysis to only a portion of the data captured, Lang said.

"Imagine the search for a very weak and elusive dark matter signal within many events from various sources of background," Lang said. "It's like looking for a needle in a haystack. While most experiments have a huge pile of hay, our detector is so sharp and the background is so low, that our haystack is small and we can easily look at every piece of hay. We don't have to pick and choose what portion of the data we evaluate; we can look at every event. This opens the door for us to find evidence of dark matter in an unexpected place or in a form we didn't consider, which is good because no one yet knows what exactly dark matter is."

Scientists from a dark matter project named Dark Matter Large Sodium Iodide Bulk for Rare Processes, and referred to as the DAMA/LIBRA project, claimed to have detected dark matter in 1998. The team observed a signal

that varied with the seasons, as is expected for dark matter as the Earth's orbit around the sun changes the speed at which it passes through a halo of dark matter that envelops the Milky Way, Lang said. However, other teams searching for dark matter did not observe the same signal. The DAMA/LIBRA team suggested that other groups could be blind to the signal because the dark matter was interacting with the atoms of the detector in an unexpected way. It was suggested that the dark matter could be leptophilic, meaning it prefers to interact with electrons, he said.

"Traditionally the 'smoking gun' signature of dark matter was considered to be scattering of dark matter particles on the nuclei of the atoms of the detector material," said Joachim Kopp, a professor of theoretical elementary particle physics at Johannes Gutenberg University Mainz who is not part of the XENON collaboration. "Indeed, this is what many well-motivated dark matter models, such as supersymmetry, predict. However, in recent years, we have begun to appreciate more and more the fact that dark matter could behave very differently in many ways."

Experimental anomalies like the controversial annual modulation signal observed in the DAMA/LIBRA project cannot be explained by traditional dark matter scattering on atomic nuclei, but could be accommodated more easily if dark matter scatters predominantly with electrons or if most of the energy released in dark matter scattering is in the form of photons, he said.

"For a long time, it was considered unfeasible to test such a model since the scattering of dark matter particles on electrons or the emission of photons is much more difficult to distinguish from radioactive backgrounds," Kopp said. "Liquid noble gas detectors like XENON100 are now setting the new gold standard in this endeavor."

The XENON100 experiment was able to examine theories others could not because of the low level of background events it achieved, said Luke Goetzke, a postdoctoral researcher at Columbia University who was a lead researcher on the XENON100 experiment detailed in Physical Review Letters.

"The material used in the XENON100 detector and the material used in the DAMA/LIBRA project are very similar in terms of their electron configurations, so if dark matter interacts with one, it would interact in nearly the same way with the other," he said. "However, the XENON100 detector is so amazingly sensitive that the signal would be much more clear. We did not see it, and given our current knowledge and understanding of physics, because we did not see it, there is no way to explain the mysterious signal as leptophilic dark matter."

While the XENON100 data did not show the same signal as that observed by the DAMA/LIBRA project, the data did show a different and faint annual modulation, he said.

"The modulation we observed raises some questions, and to me that is thrilling," Goetzke said. "This means we are pushing the limits of our understanding and that is what makes physics research fun. I am very excited to see the first data from the XENON1T experiment, which will push far beyond the already amazing results from XENON100."

The experiment is conducted by an international collaboration of 120 scientists from 22 institutions around the world and is led by Elena Aprile, a professor of astrophysics at Columbia University.

This fall the team will will deploy a next-generation detector called XENON1T, which is expected to be 100 times more sensitive than XENON100. The detector itself will be 20 times bigger and include a series of technological improvements, she said.

"From the XENON100 results we know a lot more about what dark matter is not, which is very valuable information in the field of particle physics," Aprile said. "We've ruled out models with the strongest expected dark matter interactions, and with the XENON1T detector we will be able to test those with weaker expected interactions and capture even the most feeble hint of a dark matter. The results of these experiments mean that if this is the right place to look for the signature of dark matter, we should be able to see it."

Read more at Science Daily

Aug 21, 2015

Archerfish Shoots Down Prey with Water Cannon

Even out of the water, insects throughout the forests of Australia and southeast Asia have a ruthless foe to fear: the archerfish.

From the murky depths, the sharpshooting archerfish directs a dangerous water canon toward nearby prey. The powerful spurts of water will knock an unsuspecting insect from its perch, sending it tumbling helplessly into the water in time for the archerfish to swoop in and enjoy its meal:

New research from Wake Forest University indicates that the archerfish's water canon is much more precise and complex than previously believed. In a study published in the journal Zoology, WFU researchers explain that the archerfish is capable of altering its lethal stream based on its intended target.

Analysis of high-speed footage revealed that the archerfish's jet of water merges to form a "globular mass" immediately before it hits its victim -- in order for that to happen effectively, the fish must asses the distance of target and adjust the stream accordingly.

Read more at Discovery News

Nazi Train Full of Gold Rumored to Be Found

Local media are abuzz over the rumored discovery of an armored train car in southwestern Poland, which has revived old lore of trains full of gold and jewels stolen by the Nazis that vanished after World War II.

“Has Hitler’s gold train been located?” asked the leading daily Gazeta Wyborcza in a headline echoed by broadcaster, tabloid Fakt and broadcaster TVN24 among other media.

The legends revolve around the huge secret underground tunnels near the southwestern city of Walbrzych that Nazi Germany had built by forced laborers and concentration camp inmates.

The tunnels, code-named Riese (Giant), were built to be used as production spaces for German strategic weapons as the site was safe from Allied air raids.

Portions of the tunnels are now open to tourists, while the region also attracts treasure-hunters inspired by old rumours that the Third Reich had stashed its treasures in the underground passages.

But even the two men — a German and Pole — who claim to have found a 120-150 meter-long (400-500 foot-long) train are skeptical that it contains gold, according to their lawyer.

“These are serious people… What they presented during our talk makes me believe this business (of the train) is very credible,” lawyer Jaroslaw Chmielewski told the Polish news portal Onet.

“My clients are however skeptical as to whether it is really the famous (Nazi) train” packed with gold and other precious objects, he said.

“But we also can’t completely exclude the possibility.”

Read more at Discovery News

Massive Human Skull Rack Found at Aztec Temple

Archaeologists have unearthed gruesome evidence of brutal rituals as they excavated what could be the largest ceremonial skull rack built by the Aztecs more than 500 years ago.

Found on the western side of what was once the Templo Mayor complex in Tenochtitlan, in modern Mexico City, the partially unearthed skull rack was likely built between 1485 and 1502 and may have been about 112 feet (34 meters) long and 40 feet (12 meters) wide.

Mostly belonging to young adult men, but also to women and children, several of the unearthed skulls feature holes on both sides, suggesting they belonged to a tzompantli. This was a rack on which the skulls of sacrificed people were arranged on wooden poles and displayed to inspire fear and awe.

To make the scene even more horrifying, the new finding revealed that part of the platform where the head rack once stood was made of rows of skulls mortared together in a circle.

All the skulls faced inward toward the center of the circle, although it’s unknown what was in there.

“So far we have found 35 skulls, but there must be many more in underlying layers,” archaeologist Raul Barrera of Mexico’s National Institute of Anthropology and History (INAH) said in a statement.

According to Eduardo Matos Moctezuma, one of the INAH archaeologists involved in the ongoing excavation, the skulls would belong to the Huey Tzompantli, the Great Tzompantli of Tenochtitlan (modern Mexico City) which is estimated to have contained approximately 60,000 skulls.

“We believe we have found the Huey Tzompantli. Many of these skulls could be enemies of the Aztecs who were captured, killed and beheaded in a show of might,” Matos Moctezuma said in a statement.

From Discovery News

July Was the World's Hottest Month on Record

July was the hottest month on Earth since records began, according to US scientists, with an average temperature worldwide of 61.9F (16.6C).

Scientists at the US National Oceanic and Atmospheric Administration (NOAA) said in a report that they expected 2015 to be the hottest year on record.

Nine of the 10 hottest months since records began in 1880 have occurred since 2005, and the first seven months of 2015 are the hottest January-to-July span recorded.

"The world is warming. It is continuing to warm. That is being shown time and time again in our data," said Jake Crouch, physical scientist at NOAA's National Centers for Environmental Information.

"Now that we are fairly certain that 2015 will be the warmest year on record, it is time to start looking at what are the impacts of that? What does that mean for people on the ground?" he told reporters.

Scientists said global climate change and a boost this year from an El Nino warming of the Pacific Ocean were behind the record temperatures.

Large parts of the Earth were much warmer than average, including Africa which saw its second hottest July on record.

"Record warmth was also observed across much of northern South America, parts of southern Europe and central Asia, and the far western United States," said the NOAA report.

Parts of eastern Scandinavia and western Russia, eastern and southern Asia and scattered areas in central and northern North America were cooler than average.

From Discovery News

The Fish That Wears a Suction Cup as a Hat

Yeah, that's the top of the remora's head. It's as surprised as you are!
Pliny the Elder, the legendary Roman naturalist who was nevertheless wrong about, oh, somewhere around 98 percent of the things he claimed, once wrote of the echeneis—a small, slug-like fish with a habit of sticking to ships and bringing them to a dead stop. The emperor Caligula supposedly met echeneis the hard way on a return journey to Antium. Slowed to a halt, he ordered his men to inspect the belly of the ship, and sure enough they found the fish stuck to the rudder. After they removed it and eventually reached land, Caligula’s men assassinated him, perhaps a bit upset about being clowned by a fish.

Today, biologists know that fish as the remora, literally meaning “hindrance.” And you’ve no doubt seen it before. It’s the critter that sticks to sharks, hitching a free ride and hoovering up its host’s scraps all the while. It can’t stop ships, but it is in possession of one of the most striking adaptations in the sea: a suction cup it wears for a hat.

When you see a remora stuck to the top of a shark, it’s not suctioning on with its mouth. In fact, it’s flipped upside down, using a specialized structure on the top of its head to get a grip. And it doesn’t just target sharks. Remoras go after all kinds of creatures, from sea turtles to manta rays to whales. But here’s where things get interesting: How should scientists define this relationship? Are remoras parasitic, commensal (one party benefits and the other suffers no harm), or mutualistic (both parties benefit)? It turns out this relationship is far more complicated than it seems.

First, though, that sucker. It’s actually a modified dorsal fin—that is, the kind of fin you see sharks sticking out of the water. But a baby remora isn’t born with a fully formed sucker. It has to wait for the thing to develop as it grows up. In fact, when the remora is a youngster, the developing sucker starts off where you’d expect to find a dorsal fin, then migrates forward to the top of the fish’s head during development. (Puberty, amirite?)

An animation showing the anatomy of the head of the remora and its sucker. Not a real one of course. This is an animation, as I mentioned.
Take a look at the animation above. Your typical dorsal fin has vertical spines that give it support, but in the remora’s modified sucker, those spines have flattened. Each one has split in two, one going to the left of the base and the other to the right. Combined, all the spines form a disk, which is edged with a rim of flesh to form a suction cup. As a bonus, little offshoots come off of the base of each spine. “And those are presumably the things that provide extra friction when the remora attaches,” says Dave Johnson, an ichthyologist at the Smithsonian. Thus the remora can get a grip on uneven surfaces, like the body of another living creature or the ship of a soon-to-be-assassinated Roman emperor.

(Interestingly, an unrelated species whose name does not disappoint, the clingfish, uses modified pectoral and pelvic fins to form a suction cup on its belly. This allows it to hold fast to rocks on battered shores. Two unrelated organisms arriving at a similar adaptation like this is known as convergent evolution.)

Now, there are two groups of remoras: a reef variety is less picky about what it latches onto, sharks and fish and such, while an open ocean or pelagic variety tends to specialize, sometimes hitchhiking on only one species. “The general pattern is there’s a group that will hitchhike on anything,” says Christopher Kenaley, a biologist at Boston College, “and then there’s a group that’s way offshore and sticks to bigger things and only a few things.”

Behold the remora’s sucker, the most adhesive hat on Earth other than that time a British dude super-glued a tiny hat to his head.
In either case, the remoras are getting a free ride, thus saving them valuable energy, not to mention providing them protection. But what are they feeding on? That also seems to vary between the reef and open ocean types. According to Kenaley, stomach contents from the latter show they’re mainly eating the parasitic copepods (small crustaceans) that also attach to their hosts. This would suggest that far from just mooching a ride, the remora is doing its host a service by hoovering up parasites.

But not so fast, says Kenaley. “The idea of a remora crawling up on the side of a fish and removing a parasite seems a little far-fetched. It’s probably the case that these parasites are falling off,” and the remora gobbles them up when they do. In contrast, around the reefs, remoras likely collect more scraps that their hosts don’t manage to eat—think of the cloud of flesh a shark produces when it tears its prey apart. Also, sorry to make you think of the cloud of flesh a shark produces when it tears its prey apart.

What’s a mystery, though, is what remoras feed on when they’re larvae—remember that they aren’t born with a fully realized sucker with which to latch onto other creatures. Scientists aren’t yet sure, but Johnson has a hypothesis. “Maybe they actually have an association with hosts at a very early stage,” he says, “and maybe they’re sitting, for example, inside the gill cavities of other fishes.”

A top-down view of the gnarly teeth of the larval remora (its lower jaw juts forward), which may help it cling to the gills of other fish. Boy, that remora. Always clinging to something or other.
They’ve got huge, hooked teeth as larvae, which is quite a different set of chompers than they have as adults. Perhaps they’re using them to latch onto other fishes’ gills, sitting there and picking off bits of food as their host feeds, instead of swimming around looking for their own meals. “It’s just hard to imagine what those big hook-like teeth would be there for in a free-living larva.” As of yet, though, scientists haven’t found any remora larvae lodged in fish gills, so the idea remains speculation.

As for the adult remora, whether or not it’s parasitic, commensal, or mutualistic is a tricky subject. The host may be benefiting from cleaning services—that is, the remora is plucking off parasites—though as Kenaley mentioned, it’s more likely the parasites are falling off on their own, which would mean the remora isn’t doing a lick of work. Additionally, remoras can rub their hosts raw, potentially opening them up to infection—not exactly the civilized behavior required of commensalism or mutualism.

Kenaley has also run models that show remoras significantly slow down their hosts. Not a bringing-a-ship-to-a-halt kind of slowdown, but definitely contributing some measure of drag. This would mean the host would need to put more energy into locomotion. That may not seem like a big deal, but wasting energy is a big no-no in the animal kingdom. Sharks with attached remoras would have to eat that much more to gain back the lost energy. And scientists have spotted whales with a dozen of these things attached. You can only imagine the drag involved there.

Read more at Wired Science

Aug 20, 2015

New data from Antarctic detector firms up cosmic neutrino sighting

Researchers using the IceCube Neutrino Observatory have sorted through the billions of subatomic particles that zip through its frozen cubic-kilometer-sized detector each year to gather powerful new evidence in support of 2013 observations confirming the existence of cosmic neutrinos.

The evidence is important because it heralds a new form of astronomy using neutrinos, the nearly massless high-energy particles generated in nature's accelerators: black holes, massive exploding stars and the energetic cores of galaxies. In the new study, the detection of 21 ultra high-energy muons -- secondary particles created on the very rare occasions when neutrinos interact with other particles --provides independent confirmation of astrophysical neutrinos from our galaxy as well as cosmic neutrinos from sources outside the Milky Way.

The observations were reported today (Aug. 20, 2015) in a paper published in the journal Physical Review Letters by the IceCube Collaboration, which called the data an "unequivocal signal" for astrophysical neutrinos, ultra high-energy particles that have traversed space unimpeded by stars, planets, galaxies, magnetic fields or clouds of interstellar dust -- phenomena that, at very high energies, significantly attenuate more mundane particles like photons.

Because they have almost no mass and no electric charge, neutrinos can be very hard to detect and are only observed indirectly when they collide with other particles to create muons, telltale secondary particles. What's more, there are different kinds of neutrinos produced in different astrophysical processes. The IceCube Collaboration, a large international consortium headquartered at the University of Wisconsin-Madison, has taken on the huge challenge of sifting through a mass of observations to identify perhaps a few dozen of the highest-energy neutrinos that have traveled from sources in the Milky Way and beyond our galaxy.

Those high-energy neutrinos, scientists believe, are created deep inside some of the universe's most violent phenomena. The particles created in these events, including neutrinos and cosmic rays, are accelerated to energy levels that exceed the record-setting earthbound accelerators such as the Large Hadron Collider (LHC) by a factor of more than a million. They are prized by astrophysicists because the information they hold is pristine, unchanged as the particles travel millions of light years between their sources and Earth. The ability to study the highest-energy neutrinos promises insight into a host of problems in physics, including how nature builds powerful and efficient particle accelerators in the universe.

The latest observations were made by pointing the Ice Cube Observatory -- composed of thousands of optical sensors sunk deep beneath the Antarctic ice at the South Pole -- through the Earth to observe the Northern Hemisphere sky. The Earth serves as a filter to help weed out a confusing background of muons created when cosmic rays crash into the Earth's atmosphere.

"Looking for muon neutrinos reaching the detector through the Earth is the way IceCube was supposed to do neutrino astronomy and it has delivered," explains Francis Halzen, a UW-Madison professor of physics and the principal investigator of IceCube. "This is as close to independent confirmation as one can get with a unique instrument."

Between May 2010 and May 2012, IceCube recorded more than 35,000 neutrinos. However, only about 20 of those neutrino events were clocked at energy levels indicative of astrophysical or cosmic sources.

The results are meaningful because, using the different technique, they reaffirm the IceCube Observatory's ability to sample the ghostlike neutrinos. By instrumenting a cubic kilometer of deep Antarctic ice, scientists were able to make a detector big enough to capture the signature of the rare neutrino collision. When that rare smashup occurs, it creates a muon, which, in turn, leaves a trail of Cherenkov light that faithfully mirrors the trajectory of the neutrino. The "optical sonic booms" created when neutrinos smash into another particle are sensed by the optical sensors that make up the IceCube detector array and, in theory, can be used to point back to a source.

"This is an excellent confirmation of IceCube's recent discoveries, opening the doors to a new era in particle physics," says Vladimir Papitashvili, astrophysics and geospace sciences program director in the National Science Foundation's (NSF) Division of Polar Programs. "And it became possible only because of extraordinary qualities of Antarctic ice and NSF's ability to successfully tackle enormous scientific and logistical problems in the most inhospitable places on Earth."

But while the new observations confirm the existence of astrophysical neutrinos and the means to detect them using the IceCube Observatory, actual point sources of high-energy neutrinos remain to be identified.

Albrecht Karle, a UW-Madison professor of physics and a senior author of the Physical Review Letters report, notes that while the neutrino-induced tracks recorded by the IceCube detector have a good pointing resolution, within less than a degree, the IceCube team has not observed a significant number of neutrinos emanating from any single source.

The neutrinos observed in the latest search, however, have energy levels identical to those seen when the observatory sampled the sky of the Southern Hemisphere. That, says Karle, suggests that many of the potential sources of the highest-energy neutrinos are generated beyond the Milky Way. If there were a significant number of sources in our own galaxy, he notes, the IceCube detector would light up when observing the plane of our galaxy -- the region where most neutrino-generating sources would likely be found.

Read more at Science Daily

Hummingbird's Tongue Works Like a Micropump

The slender hummingbird tongue has been misunderstood for more than 180 years, a new study finds.

Since 1833, scientists thought that hummingbird tongues used capillary action — a phenomenon in which liquid flows through narrow areas, even working against gravity — to slurp up floral nectar. Researchers got this intriguing (but wrong) idea because the birds have long groves on their tongues that look like open cylinders, said Alejandro Rico-Guevara, lead researcher of the new study and a research associate of functional morphology at the University of Connecticut.

But capillary action is slow, at least by hummingbird standards. Using high-speed videos, researchers in the new study determined that hummingbird tongues act as elastic micropumps, allowing the birds to feed at rapid speeds, Rico-Guevara said.

Most people are familiar with simple pumps — the drinking straw, for instance. When sipping a beverage through a straw, people contort their cheeks to create a vacuum in the straw and suction up the liquid, Rico-Guevara said.

The hummingbird's tongue works in a slightly similar way, but without a vacuum. After zipping toward a flower, the hummingbird flattens its outstretched tongue, and "the compressed tongue remains flattened until it contacts the nectar," the researchers wrote in the study. "After contact with the nectar surface, the tongue reshapes filling entirely with nectar."

To pull in the nectar, the top of the tongue (the part closer to the mouth) bends, so it's no longer flat, and this bending stores elastic energy, Rico-Guevara said. That energy helps draw the nectar out of the flower and into the bird's mouth, he said.

"We show that the tongue works as an elastic micropump," the researchers said. "Fluid at the tip is driven into the tongue's grooves by forces resulting from re-expansion of a collapsed section" of the tongue closer to the mouth.

This fast technique allows the bird to drain between five and 10 drops of nectar from a flower within 15 milliseconds (about 100th of a second), Rico-Guevara said.

Setting up the experiment took five years, Rico-Guevara said, and involved constructing "flowers" researchers could look into.

"When the [hummingbird's] bill goes inside a flower, you don't see what is happening inside at all," Rico-Guevara told Live Science. "My first challenge was to make see-through flowers."

He used tiny glass tubes, filled them with artificial nectar and set up the high-speed video cameras near the tubes. This setup was repeated in a number of places, including Connecticut, Texas, California, Ecuador, Columbia and Brazil.

"I tried to get as many different kinds of hummingbirds as possible," Rico-Guevara said. "Not just to get different species, but the crazy ones, the extreme ones, just to be able to generalize what happens" when they feed.

In all, he filmed 96 foraging bouts, which included 32 birds from 18 species licking up artificial nectar from the transparent tubes.

The researchers spent hours examining the footage. In 2011, they published a study explaining that the hummingbird tongue is not a capillary tube, but instead works by trapping fluid. However, they still didn't know exactly how it worked. In the new study, the researchers explained that the tongue is a tiny pump that can pull in nectar.

Rico-Guevara developed two computer models with Tai-Hsi Fan, an associate professor of mechanical engineering and expert on fluid dynamics at the University of Connecticut, to determine how the hummingbird's tongue works. One model represented capillary action, and the other emulated the elastic micropump.

"We translated all of the pieces into mathematics to create predictions that we could test," Rico-Guevara said. "The match was really great with the elastic micropump one, so we were very happy."

The models showed that if hummingbirds used capillarity in the wild, they would have to slow way down, he said. The elastic micropump method allows hummingbirds to lick a flower up to 20 times per second, or at 20 hertz.

"But if they were using capillarity, they would have to slow it down to 5 hertz," Rico-Guevara said. "Which is still pretty fast, but when you're out there and you have so much pressure [to survive], every millisecond counts."

The finding may prompt scientists to give existing hummingbird research a second look. For instance, earlier studies suggested that some flowers developed dilute nectar, which is easier for hummingbirds to consume via capillary action than is concentrated nectar.

Read more at Discovery News

ISIS Beheads Elderly Ex-Antiquities Chief in Syria's Palmyra

The Islamic State group beheaded the 82-year-old retired chief archaeologist of Palmyra after he refused to leave the ancient city, Syria’s antiquities chief said.

A UNESCO World Heritage site famed for well-preserved Greco-Roman ruins, Palmyra was seized from government forces in May, fueling fears the IS jihadists might destroy its priceless heritage as it had done in other parts of Syria and Iraq.

Syrian antiquities chief Maamoun Abdulkarim told AFP he had urged Khaled al-Assaad to leave Palmyra, but he had refused.

“He told us: ‘I am from Palmyra and I will stay here even if they kill me.’”

Abdulkarim said Assaad was murdered execution-style on Tuesday afternoon in Palmyra, in central Homs province.

“Daesh has executed one of Syria’s most important antiquities experts,” he said, using an Arabic acronym for IS.

Photos purporting to show Assaad’s body tied to a post in Palmyra were circulated online by IS supporters.

The killing is one of hundreds that have been carried out by IS in and around Palmyra since they took the city. The United States, France and UNESCO voiced outrage over Assaad’s death.

“He was the head of antiquities in Palmyra for 50 years and had been retired for 13 years,” Abdulkarim said.

He hailed Assaad as a leading expert on the ancient history of the city, which grew from a caravan oasis first mentioned in the second millennium BC.

“He spoke and read Palmyrene, and we would turn to him when we received stolen statues from the police and he would determine if they were real or fake.”

- ‘They’ll never silence history’ -

Abdulkarim said Assaad’s body had been hung in the city’s ancient ruins after being beheaded.

But the photo circulating online showed a body on a median strip of a main road, tied to what appeared to be a lamp post.

A sign attached to the body identified it as that of Assaad.

It accused him of being an apostate and a regime loyalist for representing Syria in conferences abroad with “infidels”, as well as being director of Palmyra’s “idols”.

It also claimed he had been in contact with regime officials.

Abdulkarim said Assaad had been detained by IS last month along with his son Walid, the current antiquities director for Palmyra, who was later released.

He said the jihadists were looking for “stores of gold” in the city.

“I deny wholeheartedly that these stores exist,” Abdulkarim said.

“The whole family is truly remarkable. (Assaad’s) other son Mohammed and his son-in-law Khalil actively participated in the rescue of 400 antiquities as the town was being taken over by the jihadists,” he said.

The Syrian Observatory for Human Rights, a Britain-based monitor, also reported the death, saying Assaad had been killed in a “public square in Palmyra in front of dozens of people”.

UNESCO’S director general, Irina Bokova, said she was “both saddened and outraged to learn of the brutal murder,” adding that “they killed him because he would not betray his deep commitment to Palmyra”.

“His work will live on far beyond the reach of these extremists. They murdered a great man, but they will never silence history.”

The killing also prompted condemnation from French Foreign Minister Laurent Fabius, who said Assaad had worked with numerous French archaeological missions over the years.

“This barbaric murder joins a long list of crimes committed over the past four years in Syria,” he said in a statement, calling for those responsible to be brought to justice.

In Washington, State Department spokesman John Kirby decried the “brutal, gruesome murder”.

IS captured Palmyra on May 21, prompting international concern about the fate of the city’s antiquities.

The IS group’s harsh vision of Islam considers statues and grave markers to be idolatrous, and the group has destroyed antiquities and heritage sites in other territory under its control in Syria and Iraq.

“These attempts to erase Syria’s rich history will ultimately fail,” Kirby said in Washington.

Read more at Discovery News

L.A. 'Shade Ball' Rollout a 'Potential Disaster'

LA's scheme to cover a reservoir under 96 million "shade balls" may not be all it is touted to be, experts told, with some critics going so far as to refer to the plan as a "potential disaster."

The city made national headlines last week when Mayor Eric Garcetti and Department of Water officials dumped $34.5 million worth of the tiny, black plastic balls into the city's 175-acre Van Norman Complex reservoir in the Sylmar section. Garcetti said the balls would create a surface layer that would block 300 million gallons from evaporating amid the state's crippling drought and save taxpayers $250 million.

Experts differed over the best color for the tiny plastic balls, with one telling they should have been white and another saying a chrome color would be optimal. But all agreed that the worst color for the job is the one LA chose.

"Black spheres resting in the hot sun will form a thermal blanket speeding evaporation as well as providing a huge amount of new surface area for the hot water to breed bacteria," said Matt MacLeod, founder of the California biotech firm Modern Moon Farms. "Disaster. It’s going to be a bacterial nightmare.”

Any color covering will help stop wind-driven evaporation, said Robert Shibatani. principal hydrologist for the Sacramento-based environmental consultant The Shibitani Group. But when it comes to the hot summer sun sucking water out of the reservoir, color is everything, he said.

"Ideally you would want a chrome surface," he said. "The worst would be matte black, which has a reflectivity close to zero."

Biologist Nathan Krekula, a professor of health science at Bryant & Stratton College in Milwaukee, said black balls will absorb heat, transfer it to the water and cause evaporation. And he agreed with MacLeod that the heat will prove hospitable to bacteria.

"Bacteria required a few things to grow a dark, warm and moist environment," he said. "The balls will give them the perfect environment to live in.

"What works in backyard fish pond does not always transfer to large scale system such as this, Krekula added. "Keeping the balls clean when covered in bacteria and mold slime will be a monumental task."

Dennis Santiago, a risk analyst for Torrance-based Total Bank Solutions, suspects the real goal for the black-ball cover is to avoid steep Environmental Protection Agency fines. The federal agency's "Long-Term 2 Enhanced Surface Water Treatment Rule," announced in 2006, would require public and private water utilities to spend billions to cover open-air reservoirs that hold treated water to prevent contamination. Officials in several districts around the nation have balked at the EPA mandate, notably in New York, where lawmakers are fighting to block a $1.6 billion concrete cover the EPA has ordered built over a Yonkers reservoir.

“This is not about evaporation," Santiago said. "The water savings spin is purely political. What the black balls are really about is that [Los Angeles] needs to stay in-compliance with an EPA requirement to place a physical cover over potable water reservoirs.”

Garcetti's office did note that the ball covering provides a "cost-effective investment that brings the LA Reservoir into compliance with new federal water quality mandates," but its emphasis on blocking evaporation was the clear focus at the event. Los Angeles Department of Water spokesman Albert Rodriguez told the city has plenty of time to get in compliance with the EPA.

Read more at Discovery News

Aug 19, 2015

Rare Philippine Eagle Shot Dead Three Years After Rescue

A rare giant Philippine eagle has been shot dead two months after being released back into the wild following treatment for another shooting, in a blow to efforts to save the species from extinction, conservationists said Wednesday.

The raptor's remains were found on a forest floor last weekend with a gunshot wound on its right breast, three years after it was rescued and treated, the Philippine Eagle Foundation said.

It was the 30th to be found dead or wounded out of an estimated population of just 400 pairs in the wild, which reside mainly on the large southern island of Mindanao, its executive director Joseph Salvador said.

"Unfortunately, one person with a gun thinks he can shoot anything," Salvador told AFP, adding no one has been arrested in the latest incident.

"The potential to teach people the importance of the eagles to wildlife and biodiversity has been compromised."

Famed for its elongated nape feathers that form into a shaggy crest, the Philippine eagle, one of the world's largest, grows up to a metre (3.3 feet) long with a two-metre wingspan.

The Swiss-based International Union for the Conservation of Nature lists the species as "critically endangered", due to the depletion of its tropical rainforest habitat and hunting.

Philippine eagles kill macaques and other smaller animals for food and need vast tracts of forest as hunting grounds, routinely driving away rivals from their territory.

Gunshots accounted for nine out of every 10 Philippine eagle casualties recorded by the foundation over seven years.

The latest bird to be killed had been rescued as a juvenile three years ago and treated for superficial gunshot wounds.

Returned to the wild in Mindanao's Mount Hamiguitan reserve two months ago, the eagle's carcass was tracked about a kilometre (half a mile) away from where it was released, after a fitted radio transmitter indicated the bird had stopped moving.

Read more at Discovery News

'Winged Monster' Rock Art Finally Deciphered

The mystery surrounding the ancient rock paintings of Utah’s Black Dragon Canyon has finally been solved. For decades, researchers and creationists have debated whether the vibrant red pictographs are images of humans and animals, or rather, depictions of a large winged monster, possibly a pterosaur.

Now, using cutting-edge technology, researchers suggest the red paintings show five separate images, including a tall bug-eyed person, a smaller person, a sheep, a dog and a serpentlike figure.

“It is not a single figure. It is not a pterodactyl,” said co-lead researcher Paul Bahn, a freelance archaeologist. “It’s a beautiful set of images.”

The rock paintings belong to the agrarian Fremont culture (circa A.D. 1 to 1100). Other Fremont rock paintings — known as Barrier Canyon style — show abstract humanlike figures with elongated bodies and round heads, the researchers wrote in the study. These long figures are usually accompanied by tiny “attendants,” including people, birds and four-legged creatures, such as hoofed animals, canines, felines, badgers and bears.

Amateurs discovered the painting in 1928, and soon after talk of the “winged monster” arose. In 1947, a man named John Simonson traced over the paintings with chalk and said the end result looked like “a weird bird.”

Chalking rock art was a common practice in earlier years — ancient rock art is usually faint, and chalk can help make it visible — but today it’s illegal, Bahn said.

“It’s one of the worst things you can do, because it damages the art, it imposes what you think you can see on it, it messes up the chemistry of the rock, probably, and it just doesn’t disappear,” Bahn told Live Science.

Intriguing interpretations

The chalking may have influenced subsequent viewings of the art. Rock-art specialist Polly Schaafsma said she saw a “beak lined with sharp teeth” in a 1970 report. In 1979, geologist Francis Barnes said it looked “very much like a pterosaur, a Cretaceous flying reptile.”

The fossils of pterosaurs, flying reptiles that lived from 228 million to 66 million years ago, are found in the region. Some creationists began saying that the painting was a real-life impression of pterosaurs that lived at the same time as humans, and a few people even tried to identify the species, saying it was Quetzalcoatlus northropi, a reptile with a wingspan of about 39 feet (12 meters), Bahn said. (Many creationists believe the Earth is just several thousand years old, instead of about 4.5 billion years old, and as such humans and dinosaurs would have lived together.)

But to many researchers, the painted area clearly shows separate images, not a single image of a pterosaur.

“I myself visited the site in person a few years ago,” said Phil Senter, an associate professor of biology at Fayetteville State University in North Carolina, who was not associated with the study. “There’s no pterodactyl there at all. It’s a collection of other images.”

Benjamin Smith, a professor of world rock art at the University of Western Australia, stressed that humans knew little about dinosaurs and other extinct animals until the 1800s, long after the Fremont culture people painted Black Dragon Canyon.

“Since Native American art is of spiritual significance and holds significant religious content, images can also depict magical and mythical subject matter,” said Smith, who was not involved with the study. “Not all animals in Native American art therefore need to depict real-world creatures. Some will be supernatural, but none will be dinosaurs.”

Novel techniques

Bahn and his colleague Jean-Loi?c Le Quellec, a rock-art expert at the French National Centre for Scientific Research, traveled to Black Rock Canyon for their new TV documentary series, “On the Rocks,” in which they feature rock art from around the world.

Other experts have written studies that attempt to debunk the creationist pterosaur interpretation, but the new study is the first to use cutting-edge techniques, including a tool called DStretch and a portable X-ray fluorescence device, Bahn said.

With DStretch, researchers can photograph a pictograph and upload it onto a computer. The program then helps researchers highlight the original pigmentsin the painting, in this case ochre, even when the colors aren’t visible to the naked eye. Users can also disentangle colors from unwanted additions, such as chalk.

“Where you’ve got paint that has faded over the hundreds or thousands of years, DStretch will make them very clear and very visible,” Bahn said.

The DStretch results showed “very clearly that these are a set of separate figures,” he said. “What was supposed to be one wing of this pterodactyl is actually two little four-legged animals. The so-called head and beak and neck of the pterodactyl actually a human figure with its spindly legs and its two arms stretching out.”

Marvin Rowe, a rock-art expert and professor emeritus of chemistry at Texas A&M University, scanned the cave art with portable X-ray fluorescence, which reveals an artifact’s chemical makeup.

“He showed that where there are paintings, you get a tremendously high reading of iron, of course, because it’s iron oxide, this paint,” Bahn said. “In other areas, between the so-called neck of the pterodactyl and its body, there’s nothing, because there is no paint there.”

With these two methods — the DStretch and the X-ray fluorescence — the researchers say in the study that they removed the “interpretational bias” that is inherent with eyeballing rock art, and used a scientifically replicable process instead.

But the pterosaur perception will likely continue to linger, Bahn said.

On the new documentary, the researchers invited a creationist to view their results. “We were all very polite to each other, and he showed us what he thought he saw on the wall,” Bahn said. “We said, ‘It looks like a number of separate figures to us.’”

Read more at Discovery News

Earliest 'Modern' Hand Bone Nearly 2 Million Years Old

A tiny bone from the little finger of a human ancestor that lived more than 1.84 million years ago in East Africa is the oldest "modern" hand bone ever found, say scientists.

The pinkie bone pushes back in time a key step in the evolution of our forebear from tree-climbing foragers to tool-wielding hunters.

Analysis of the bone also hints at the existence of a larger, more human-like creature than others known to have lived at that time in the same region -- one of the hotspots of human origin -- in Tanzania, report the scientists in the journal Nature Communications.

The hand is one of the critical anatomical features distinguishing humans, and even a 3.6-centimeter two-million-year-old fragment can reveal a lot about body type and behaviour.

The shape of our forebears' hands was both a reflection of their stage of evolution, and a driver of that evolution, says lead author Manuel Dominguez-Rodrigo, a researcher at the Institute of Evolution in Africa in Madrid.

"Our hand evolved to allow us a variety of grips and enough gripping power to allow us the widest range of manipulation observed in any primate," says Dominguez-Rodrigo.

"It is this manipulation capability that interacted with our brains to develop our intelligence, mainly through the invention and use of tools."

What scientists call "modern human-like" hand anatomy has several defining characteristics.

One is a longer thumb, allowing us to grip more precisely and to open our hands more fully.

Another is the straightening of our phalanges, the general name given to the three bones found in each finger. Curved phalanges were adapted for climbing trees and swinging from branches.

"A modern-like hand in the past would tell us when humans became fully terrestrial and when and how efficiently our ancestors used tools," says Dominguez-Rodrigo.

That transition happened in two main stages.

After the earliest hominins -- which includes all members of the Homo genus -- began walking on two legs some six million years ago, the hand evolved a longer thumb.

But the fingers remained curved, suggesting that trees remained part of their habitat.

This "double locomotion" -- on the ground, through the trees -- remained the norm for another four million years.

As our ancestors -- step two -- abandoned their arboral perches, their fingers began to straighten, opening the way for the creation and use of tools.

"Hands were freed from locomotion in trees so that they could become strictly specialised in manipulation," says Dominguez-Rodrigo. "This is where our discovery fills a gap."

The earliest confirmed stone tools date from about 2.6 million years ago.

The find will fuel ongoing debate as to which of our distant relatives -- Homo habilis or Homo erectus -- might have been the first to make stone implements and weapons.

"Our discovery not only shows that a creature" -- dubbed OH 86 -- "with a modern-looking hand existed 1.85 million years ago, it also shows that OH 86 was bigger sized than any other prior and contemporary hominin," says Dominguez-Rodrigo.

Archeological evidence from the Olduvai Gorge in Tanzania, where the little finger bone was found, shows that size mattered.

Fossils reveal that early human ancestors hauled the carcasses of big animals, sometimes weighing hundreds of kilos.

"I always had trouble understanding how Homo habilis -- barely taller than one meter -- could efficiently hunt animals that big," says Dominguez-Rodrigo.

The existence of a bigger, more modern-looking hominin would help explain this puzzle.

"It brings support to those who challenge the view that Homo habilis was the maker of the stone artifacts becoming abundant in layers of this time period," says Professor Jean-Jacques Hublin, director of the department of human evolution at the Max Planck Institute for Evolutionary Anthropology.

But at the same time, Hublin and others challenge the broad conclusions reached on the basis of such slim evidence.

"One single bone from a pinkie finger does not imply a whole modern human-like skeleton," says Hublin, who was not involved in the study.

Dr Tracy L. Kivell of the School of Anthropology and Conservation at the University of Kent, was even more sceptical.

Read more at Discovery News

Tiny Pebbles Built the Gas Giant Behemoths

Scientists have long puzzled over how gas planets like Jupiter and Saturn got to be so big.

Current theories suggest the cores of these behemoths are comprised of mini-planets, some 62- to 620 miles in diameter, which collided and gradually merged together over time.  But computer simulations show this process is more likely to produce hundreds of Earth-sized worlds.

“Rather than creating a few such cores, (this process) produces a population of hundreds of Earth-mass objects that are inconsistent with the structure of the solar system,” astronomer Harold Levison, with the Southwest Research Institute in Boulder, Colo., writes in this week’s Nature.

Levison and colleagues say new computer models point to an alternative scenario to form the cores of gas giants, a process they call  “slow pebble accretion.”

“If pebbles form slowly enough to allow the planetesimals to gravitationally interact with one another … the largest planetesimals have time to scatter their smaller siblings out of the disk of pebbles, thereby stifling their growth,” Levison writes.

The new models show that slow pebble accretion produces one to four gas giants, orbiting between five and 15 times farther away from the sun than Earth, a close match to the observed structure of the solar system.

From Discovery News

Aug 18, 2015

Dog Ancestors Evolved From Mongoose-Like Forest Dwellers

The first canines emerged in North America, where climate change transformed them from mongoose-like forest dwellers into pursuit-and-pounce predators, new research finds.

The discovery adds to the growing body of evidence that climate change dramatically affects the evolution of both predators and their prey.

“It’s reinforcing the idea that predators may be as directly sensitive to climate and habitat as herbivores,” co-author Christine Janis, a professor of ecology and evolutionary biology at Brown University, said in a press release. “Although this seems logical, it hadn’t been demonstrated before.”

The study, published in the journal Nature Communications, also reinforces prior findings that the earliest ancestors of dogs were native to North America.

“Dogs, that is the family Canidae, originated in North America, and did not spread to other parts of the world until around 7 million years ago, when they turn up in Africa and Eurasia, and they got to South America around 2 million years ago,” Janis told Discovery News.

She added, “Only the subfamily Caninae ever made it out of North America; the Hesperocyoninae and Borophaginae were exclusively North American.”

Janis conducted the new research with lead author Borja Figueirido of the Universidad de Málaga, Jack Tseng of the American Museum of Natural History and their team.

The scientists examined the elbows and teeth of 32 species of dogs spanning the period from around 40 million years ago to 2 million years ago.

Janis explained, “The elbow is a really good proxy for what carnivores are doing with their forelimbs, which tells their entire locomotion repertoire.”

As a result, the researchers were able to identify distinct patterns in the fossils that they believe corresponded to climate change.

The scientists determined that as forests slowly gave way to open grasslands due to cooler yet drier conditions, canines evolved from being wily ambush predators into hunters like modern coyotes or foxes that are known as pursuit-pounce predators.

As time went on, the predators further evolved into what the researchers say were “dogged, follow-a-caribou-for-a-whole-day pursuers like wolves in the high latitudes.”

Canine elbows at first could swivel (palms could be inward or down), permitting grabbing and wrestling prey. They gradually evolved to become always downward-facing and specialized for endurance running.

While all of this was happening, the canines’ teeth evolved to become more durable, perhaps with, as the researchers noted, “the need to chow down on prey that had been rolled around in the grit of the savannah, rather than a damp, leafy forest floor.”

Read more at Discovery News

First-Ever Salamander in Amber Found in Caribbean

Some 20-30 million years ago, a salamander in what is today the Dominican Republic had a very bad day.

But its misfortune has sparked a knowledge trifecta for scientists from Oregon State University (OSU) and the University of California at Berkeley. It's the first salamander fossil ever to be found encased in amber; it's from a never-before-seen and now extinct species; and it confirms that salamanders once lived in the Caribbean, a place they are not found today.

The crime scene paints a grim picture for the poor salamander, which was just a baby. It got into a skirmish of some kind and had a leg bitten off, and then it somehow became stuck for eternity in a resin deposit.

The scientists were stunned by their find.

"There are very few salamander fossils of any type, and no one has ever found a salamander preserved in amber," said George Poinar, Jr., a professor emeritus in the OSU College of Science, in a press release. "And finding it in Dominican amber was especially unexpected, because today no salamanders, even living ones, have ever been found in that region."

The researchers, who have just published their findings about the new salamander in the journal Paleodiversity, have named the creature Palaeoplethodon hispaniolae.

The family in which the salamander belonged, Plethodontidae, is common in North America, especially the Appalachian Mountains. But the newly discovered salamander did not have distinctive back- or front-leg toes (see artist's conception above). Instead, it had a kind of webbing that might have made it a not terribly expert climber, when compared to some species today, the scientists said. As a result, they say, the salamander may have lived in smaller trees or on tropical flowering plants.

The team found its all-star specimen in an amber mine in a mountainous region between Puerto Plata and Santiago.

Read more at Discovery News

Oldest Case of Leukemia Found on 7,000-Year-Old Skeleton

German researchers have discovered what might be the earliest case of leukemia in a 7,000-year-old skeleton, they announced at the first European conference on evolutionary medicine.

Belonging to a female individual who died at 30-40 years, the skeleton was excavated in 1982 among other 72 burials at an early Neolithic site near Stuttgart-Mühlhausen in south western Germany.

Beside the individual stood a round-bottomed jar. The site was linked with the Linear Pottery culture, an early farming culture which flourished in western and central Europe between 5500–4800 BC and produced pottery with distinctive linear decorations.

“So far only a severe case of dental caries with alveolar inflammation was reported for this individual,” team leader Heike Scherf, from the Senckenberg Center for Human Evolution and Paleoenvironment at the University of Tübingen in Germany, said.

Using high resolution CT scans, Scherf and colleagues found a pattern of deep loss of spongy bone in both the bone tissue of the humerus (the long bone that runs from the shoulder to the elbow) and the sternum, or breastbone.

According to the researchers, the resorption of central spongy bone is significantly higher compared to specimens of the same age group from the same site and to recent human samples of the adult age class.

“Our results strongly suggests leukemia in its initial stages, affecting the hematopoietic stem cells in bone marrow,” Scherf said.

The locally restricted destruction of the sternum and humerus’s bone tissue ruled out other diseases such as osteoporosis, hyperparathyroidism and bone tumor.

“A virus associated with a special type of leukemia (T-cell leukemia) was previously found in Andean mummies. But this case is probably the earliest known appearance of leukemia in an archeological case,” Scherf told Discovery News.

The researchers admitted it’s impossible to make any more detailed assumptions, such as establishing the type of leukemia that affected the Neolithic woman.

Read more at Discovery News

Neolithic Mass Grave Paints Picture of Brutal Conflict

A mass grave with at least 26 human skeletons discovered in Germany shows that conflict in Neolithic Europe some 7,000 years ago could be horrifically brutal, with victims tortured and mutilated, reports a new scientific study.

The discovery adds fresh evidence to the theory that mass violence played a crucial role at the beginning of the Neolithic era, and might have contributed to the decline of the so-called Linear Pottery culture, said the study, published Monday in the Proceedings of the National Academy of Sciences of the US.

The significance of such ancient mass graves -– which remain rare -- has been hotly debated by experts.

The last one was found in 2006 in Germany during a road construction project.

Evidence to date suggests that "massacres of entire communities were not isolated occurrences but rather were frequent features of the last phases" of the Linear Pottery culture, the authors conclude.

Analysis of the 26 people in the grave indicate that the victims had not been buried with typical funeral rites.

Rather, the skulls of many of the skeletons were smashed in by violent blows, in addition to arrow injuries that may have killed or immobilized the victims.

Unique to the new site is the discovery of skeletons with significant trauma in their lower legs, indicating they were tortured or mutilated before after death, researchers said.

The study speculates that a clash over resources, possibly exacerbated by drought, could have sparked conflict between groups.

From Discovery News

The Moon is Surrounded by Neon, NASA Probe Reveals

Finally, we have proof of the moon’s “noble” heritage! Measurements from NASA’s Lunar Atmosphere and Dust Environment Explorer, aka LADEE (pronounced “laddie”) have confirmed the long-suspected presence of neon in its atmosphere (neon is one of the noble gases — see what I did there?) along with isotopes of argon and helium. The relative concentrations of each of these elements also appears to depend on the time of day.

“The presence of neon in the exosphere of the moon has been a subject of speculation since the Apollo missions, but no credible detections were made,” said Mehdi Benna of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County, lead author of a paper describing the findings. “We were very pleased to not only finally confirm its presence, but to show that it is relatively abundant.”

Of course, this has nothing to do with the appearance of the moon from Earth. Despite its “relative abundance” the amount of neon in the lunar atmosphere is much too sparse to actually create any visible glow.

These elements in the lunar atmosphere have their source in the solar wind. As this constant stream of charged particles from the sun encounters the moon, heavier elements remain on the surface while lighter and more volatile elements like neon and argon return to space… except for the small portion that get trapped by gravity.

While we say “atmosphere,” in realty what the moon has is an exosphere — an extremely diffuse cloud of atoms, ions, and fine dust particles held in place by the moon’s weak gravity. It’s nothing a human could breathe or even feel; it’s 100 trillion times less dense than air on Earth at sea level.

Still, it’s something that interacts with the solar wind environment and, possibly, whatever activities we may one day establish on the lunar surface. Such a thin and fragile exosphere could easily be disturbed by rocket exhaust or outgassing from a permanent base, for example.

“It’s critical to learn about the lunar exosphere before sustained human exploration substantially alters it,” said Benna.

The presence of the moon’s exosphere was famously hinted at in a series of sketches made by Apollo 17 astronaut Gene Cernan, who claimed to have witnessed a lunar horizon glow (referred to as LHG in true NASA form) as well as long “streamers” of light preceding a sunrise from lunar orbit. While LADEE could not observe this phenomenon with its star tracker cameras, its Neutral Mass Spectrometer did collect the numbers.

Read more at Discovery News

Aug 17, 2015

Supernovae discovered in 'wrong place at wrong time'

Scientists have been fascinated by a series of unusual exploding stars--outcasts beyond the typical cozy confines of their galaxies. A new analysis of 13 supernovae -- including archived data from NASA's Hubble Space Telescope -- is helping astronomers explain how some young stars exploded sooner than expected, hurling them to a lonely place far from their host galaxies.

It's a complicated mystery of double-star systems, merging galaxies, and twin black holes that began in 2000 when the first such supernova was discovered, according to study leader Ryan Foley, University of Illinois at Urbana-Champaign. "This story has taken lots of twists and turns, and I was surprised every step of the way," he said. "We knew these stars had to be far from the source of their explosion as supernovae and wanted to find out how they arrived at their current homes."

Foley thought that the doomed stars had somehow migrated to their final resting spots. To prove his idea, he studied data from the Lick Observatory in California and the W. M. Keck Observatory and the Subaru Telescope, both in Hawaii, to determine how fast the stars were traveling. To his surprise, he discovered that the doomed stars were zipping along at about the same speed as stars that have been tossed out of our Milky Way galaxy by its central supermassive black hole, at more than 5 million miles (7 million kilometers) an hour. The astronomer then turned his attention to the aging galaxies in the area of the speeding supernovae. Studying Hubble archival images, he confirmed that many are massive elliptical galaxies that were merging or had recently merged with other galaxies. The lanes are the shredded remnants of a cannibalized galaxy. Other observations provided circumstantial evidence for such encounters, showing that the cores of many of these galaxies had active supermassive black holes fueled by the collision. Many of the galaxies also reside in dense environments at the heart of galaxy clusters, a prime area for mergers. The telltale clue was strong dust lanes piercing through the centers of several of them.

The location of the supernovae in relation to ancient galaxies indicates that the original stars must have been old, too, Foley reasoned. And if the stars were old, then they must have had companions with them that provided enough material to trigger a supernova blast.

How does a double-star system escape the boundaries of a galaxy?

Foley hypothesizes that a pair of supermassive black holes in the merging galaxies can provide the gravitational slingshot to rocket the binary stars into intergalactic space. Hubble observations reveal that nearly every galaxy has a massive black hole at its center. According to Foley's scenario, after two galaxies merge, their black holes migrate to the center of the new galaxy, each with a trailing a cluster of stars. As the black holes dance around each other, slowly getting closer, one of the binary stars in the black holes' entourage may wander too close to the other black hole. Many of these stars will be flung far away, and those ejected stars in surviving binary systems will orbit even closer after the encounter, which speeds up the merger.

"With a single black hole, occasionally a star will wander too close to it and have an extreme interaction," Foley said. "With two black holes, there are two reservoirs of stars being dragged close to another black hole. This dramatically increases the likelihood that a star is ejected." While the black hole at the center of the Milky Way may eject about one star a century, a binary supermassive black hole may kick out 100 stars a year.

After getting booted out of the galaxy, the binary stars move closer together as their orbits continue to accelerate, which speeds up the binary stars' aging process. The binary stars are likely both white dwarfs, which are the burned out relics of stars. Eventually, the white dwarfs get close enough that one is ripped apart by tidal forces. As material from the dead star is quickly dumped onto the surviving star, an explosion occurs, causing the supernova.

The time it takes for one of these ejected stars to explode is relatively short, about 50 million years. Normally, these kinds of binary stars take a long time to merge, probably much longer than the age of the universe, which is more than 13 billion years.

Read more at Science Daily

Elephant Skin Graft Gives Mutilated Rhino Second Chance

A rhinoceros in South Africa that was mutilated by poachers for its horn is getting a chance to recover after receiving a skin graft from an elephant, a veterinarian told AFP Saturday.

The female rhino was attacked two weeks ago by poachers who removed one of its horns and also killed the rhino's baby.

The operation to treat the wound took an hour and a half and was funded by the NGO "Saving the Survivors" which rescues animals left mutilated by poachers.

"This is the first time we are using elephant skin to heal a wound on a rhinoceros," said Johan Marais, the veterinarian who performed the operation in Pretoria.

Marais said that the procedure was not intended to reconstruct the horn, but simply to cover the wound.

The elephant skin came from an animal that died of natural causes, and was obtained from a taxidermist, Marais said.

The rhinoceros was treated last week, and it will take two to three weeks to know if the skin graft was successful, according to the veterinarian.

If all goes well, the technique could be used more often because only a small piece of skin is needed for the treatment.

Demand for rhino horns, which are used in traditional Asian medicine, has exploded in recent years. In China and Southeast Asia, a kilo of rhino horn sells for more than 55,000 euros (US $61,000).

From Discovery News

Mythical First Flower Found

A dinosaur-era freshwater plant from Spain has just been identified as the world’s oldest known flowering plant.

The plant Montsechia vidalii, described in the latest issue of the Proceedings of the National Academy of Sciences, has been dated to approximately 130 million years ago when dinosaurs were Earth’s dominant land animals.

The Cretaceous Period plant once grew abundantly in freshwater lakes in what are now mountainous regions in Spain. It slightly edges out another early flowering plant, China’s Archaefructus sinensis, as being the earliest known flower. Like Montsechia, Archaefructus was an aquatic species.

“A ‘first flower’ is technically a myth, like the ‘first human,’” co-author David Dilcher, a paleobotanist at Indiana University, said in a press release. “But based on this new analysis, we know now that Montsechia is contemporaneous, if not more ancient, than Archaefructus.”

Dilcher and an international team of researchers analyzed more than 1,000 fossilized remains of Montsechia. They applied hydrochloric acid drop by drop to stones containing the plants, in order to reveal the precise structures of stems and leaves. A mixture of nitric acid and potassium chlorate was also used to unveil the shape of the plant’s cuticles. These are the protective films that cover leaves.

All of the above was done under extremely high magnification, allowing the scientists to see every fossilized detail.

As for dating the plant remains, the researchers compared them to other fossils in the same area, such as those for the freshwater algae charophytes. Based on the determined age, the flowering plant co-existed with dinosaurs, such as Brachiosaurus and Iguanodon.

Montsechia was classified as a flowering plant (angiosperm) because it produced seeds enclosed within a carpel. A carpel, in turn, is the female reproductive organ of a flower.

“Montsechia possesses no obvious ‘flower parts,’ such as petals or nectar-producing structures for attracting insects, and lived out its entire life cycle under water,” Dilcher said. “The fruit contains a single seed” — the defining characteristic of an angiosperm — “which is borne upside down.”

Read more at Discovery News

Saharan Heat Amped Up by Climate Change

The searing Sahara Desert is getting even hotter, at a rate two to four times greater than the rest of the tropics, say scientists in a new study.

That puts it on par with the Arctic which is also exceeding the global warming average. But whereas the widely studied Arctic "amplification" melts sea ice and permafrost, the Sahara warming could be reducing the huge outflow of dust that blows off Africa and be causing big changes to regional weather — and local people.

"A lot of people live there – three million or so," said researcher Kerry Cook of the University of Texas at Austin. "And it's adjacent to the Sahel region, which has many more people."

The Sahara is the world's largest non-polar desert, covering 6 percent of Earth's land surface. At 3.6 million square miles, it is larger than Australia, or the lower 48 United States.

Cook and her coauthor Edward Vizy looked at five separate temperature data sets to glean what happened in the Sahara from 1979 to 2012. They found that whereas the warming in the Earth’s tropics is about a quarter of a degree Celsius, and global warming for the periods was a half degree Celsius, the warming in the Sahara Desert was more than 1 degree Celsius.

They published their results in a paper in the August issue of Journal of Climate.

Just why it is warming faster than other regions is not at all clear, said Cook. One possibility is that the hot arid land simply can’t transfer heat up and away, as other, moister lands do.

"In most places evaporated water cools the surface and water goes up to upper troposphere and heats the air there," Cook said. The water vapor serves as a sort of heat elevator, in other words. But that doesn't happen in the Sahara because it's very dry. So the heat just stays at the surface.

A similar thing happens in the Arctic. There global warming is melting the ice, revealing the darker ground or dark open waters which absorb the sunlight and warm up up the air near the surface (as opposed to reflecting that sunlight off snow and ice). The warmth stays trapped near the ground, like a smog layer in a city, because of the very stable layers of air above the Arctic.

"That's why [the Sahara heating] is analogous to polar amplification," said Cook.

But unlike the Arctic the Sahara has millions of people who are vulnerable to heat stress and dehydration as their oases and reservoirs dry up. The higher temperatures are also increasing the differences between the Sahara and the more slowly warming areas around it. It’s these sorts of temperature differences, or gradients, between the Sahara and the Atlantic that help draw in rains to the Sahel region.

"As you go north from the equator it gets hotter in the summer," said Cook. That's only true in the Sahara, not in any other part of the tropics. "That increases the flow of moisture to the Sahel from North Atlantic and is driven by the gradients."

In the winter, the high pressure that normally sits atop the Sahara has been weakening over the decades, which could affect the amount of dust worldwide.

"The Sahara and Sahel are primary sources of mineral dust for the global atmosphere when surface material is suspended by the northeasterly surface winds in winter," Cook explained. "Amplified Sahara warming in winter would weaken this high and the northeasterly flow, and reduce the suspension of mineral dust."

If that happens it could be bad news to the Amazon, Caribbean, the equatorial Atlantic, Europe, and the Mediterranean Sea all of which are fertilized by the mineral dust. But it's not yet clear that is the case.

Read more at Discovery News

Cassini to Buzz Saturn's Moon Dione One Last Time

As we rapidly approach Cassini’s thrilling final stages of its mission, the list of “final” events is gradually shrinking. Next on the NASA spacecraft’s final list is Dione — coming within 295 miles (474 kilometers) of the Saturn moon’s surface on Aug. 17 (Monday).

This close approach will be used by mission scientists to carry out a high-resolution imaging campaign of the moon’s cratered surface and gain an intimate measure of its gravitational field, revealing some further detail of its interior.

Also, scientists will be gaining high-resolution spectrometry data of its surface and infrared instruments will map out regions on the 700 mile-wide moon that are known to have “unusual thermal anomalies,” according to a NASA news release.

Although Monday’s flyby will be close, it’s not Cassini’s closest pass of Dione. In 2011, the mission came within 60 miles (100 kilometers) from the surface, revealing some surprising evidence of geological activity and, possibly, evidence of cryo-volcanoes. Now mission scientists are excited for the mission’s fifth pass, as it’s their last opportunity to unravel Dione’s mysteries.

“Dione has been an enigma, giving hints of active geologic processes, including a transient atmosphere and evidence of ice volcanoes. But we’ve never found the smoking gun. The fifth flyby of Dione will be our last chance,” said Cassini science team member Bonnie Buratti, at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Since arriving in Saturn orbit in 2004, Cassini has only been able to gain such a close view of a handful of Saturn’s 62 known moons, so every flyby of the Saturnian satellites it can make close encounters with is of extreme scientific importance.

From Discovery News

Aug 16, 2015

Deep-Sea Critter Has Spaghetti-Like Appendages

It’s white. It’s weird. It looks like a bowl of noodles turned upside down underwater. What is it? It’s a “flying spaghetti monster.”

Actually, “it” (the bizarre-looking creature) is Bathyphysa conifer, a deep-sea critter that was recently seen swimming off the coast of Angola. Workers at the oil and gas company BP videotaped this strange-looking animal while collecting video footage some 4,000 feet (1,220 meters) under the sea with a remotely operated underwater vehicle (ROV). Not knowing what the noodle-armed creature was, the BP crewmembers named it after what they thought it most resembled: the deity of the Church of the Flying Spaghetti Monster.

But researchers at the National Oceanography Centre in Southampton, England, later identified the creature as a siphonophore. Related to jellyfish and corals, siphonophores are “colonial animals,” according to a website dedicated to these fascinating creatures. The site was created by Casey Dunn, an associate professor of ecology and evolutionary biology at Brown University in Rhode Island.

Similar to corals, the spaghettilike B. conifer is made up of many different multicellular organisms known as zooids. These organisms are a lot like regular, solitary animals, except that they’re attached to other zooids, forming a more complex organism. One zooid, developed from a fertilized egg, starts the process, and then other zooids bud from the original zooid until a whole animal is formed, according to the siphonophore website.

And each zooid has a job to do. In the case of B. conifer, some of the constituent zooids specialize in catching food and eating it, while others specialize in reproducing, for example. The zooids that can’t feed, don’t feed. The ones that can’t reproduce, don’t reproduce. But together, all the zooids survive just fine.

The deep-sea “spaghetti monster” is a particular kind of siphonophore, belonging to the suborder Cystonectae, according to the World Register of Marine Species. This species of cystonect is relatively rare, according to Catriona Munro, a doctoral student in ecology and evolutionary biology at Brown University. While several B. conifer specimens have been described, researchers don’t often see these creatures in their native habitats, Munro told Live Science.

Cystonects are made up of two main parts, anchored to a long stem. Up top, there is a pneumatophore, a gas-filled “float” that looks kind of like a big bubble. (That’s the bulbous-looking thing sticking out from the top part of the spaghetti monster.) Farther down the stem is a siphosome, where a bunch of zooids are hard at work catching and eating food, reproducing, and doing all the other things the animal needs to do to survive. Unlike some other siphonophores, B. conifer and other cystonects lack a nectosome, another body part containing zooids that would propel the animal through the water.

Those armlike appendages poking through B. conifer’s mass of “spaghetti” are gastrozooids, or feeding polyps, that the creature uses to catch food, Munro said.

But it’s the animal’s ptera, or side wings, that helped researchers identify the spaghetti monster as B. conifer, according to the SERPENT Project (short for Scientific and Environmental ROV Partnership Using Existing Industrial Technology). This project is part of the National Oceanography Centre and is also the group responsible for identifying the siphonophore in BP’s footage.

The wings, which are located on the top part of the animal near the bulbous pneumatophore, are also used by the gastrozooids, but not to catch food, Munro said. Some cystonect species have ptera with multiple “side branches,” but this species does not. Its lack of side branches helped SERPENT researchers determine that the spaghetti monster is most likely B. conifer.

Read more at Discovery News

Toxic Spill in Animas River Spawns Conspiracies

Earlier this month contractors working for the U.S. Environmental Protection Agency (EPA) accidentally released about 3 million gallons of toxic mine waste into Colorado’s Animas River. The stew of toxic elements turned the river orange and caused great concern for wildlife, farmers, tourism and those who depend on the river for drinking water.

Tests conducted earlier this week are showing that levels of lead, arsenic, mercury and other toxic elements in the river are returning to safe levels. It’s important to note that, especially in rural areas, drinking water from wells contains naturally-occurring levels of these elements. However many are concerned that, though the water itself may not be hazardous, the river’s sediments may be toxic and remain so for years to come.

Accidents and disasters — especially life-threatening ones, though the Animas spill is not known to have harmed anyone yet — often spawn conspiracy theories. The most popular theory claims that the EPA purposely polluted the river as a way to obtain extra funding available for cleanup. Under this classic “follow the money” scenario the EPA decided the best way to get free up money for Superfund sites – as this could potentially be designated – was to create a disaster.

One typical conspiracy commenter opined, “I am thinking there were multiple reasons for something like this — funding, but also Agenda21  — re-wilding of the west — they want most all of the US to be “NO HUMANS ALLOWED” … plus if people get sick/die from the heavy metals in the process, it’s the sacrifice that must be made (from their perspective).”

If this conspiracy is true, EPA administrator Gina McCarthy has made an incredible sacrifice of her agency’s credibility — and potentially her own career — to secure extra government money for her agency. This is akin to claiming that police are committing crimes in order to inflate the crime rate and justify bigger budgets.

As evidence of this conspiracy, proponents point to a Letter to the Editor published shortly before the spill in a regional Colorado newspaper written by a retired geologist which seems to predict that the EPA is up to something nefarious.

Ironically the letter actually contradicts key claims made by the conspiracy theorists who promote it. It does not predict an intentional spill of mine water into the Animas (or any other) river by the EPA but instead that well-meaning efforts at preventing seepage of mine waste might result in water being backed up and releasing on its own.

Furthermore a careful reading of the letter clearly states that the EPA’s hidden agenda is not — as the conspiracy theorists claim – gaining access to Superfund money through creating a natural disaster but instead “construction of a treatment plant” for treating existing mine waste. In fact the writer explicitly states that “with a budget of $8.2 billion and 17,000 employees, the EPA needs new, big projects to justify their existence.”

In other words according to the geologist, the EPA’s struggle is not getting more money but using the money it has.

Conspiracy Theories

It may seem odd that an obvious environmental accident would prompt conspiracies, but there are several reasons for this. In the world of conspiracies, as the saying goes, “there are no accidents.”

Princess Diana’s death from a car “accident,” for example, was in fact a cleverly disguised assassination by the British intelligence agencies — or those upset at her romance with an Arab man, or any number of others who supposedly wanted Diana dead. Even hurricanes, wildfires, tsunamis, and other obviously natural disasters are suspected of being part of a dark conspiracy, including the 2010 Haiti earthquake.

Another element is the paradoxical assumptions that conspiracy theorists make regarding government competence: On one hand they believe that no one would be stupid or careless enough to “accidentally” trigger a breach in a retaining lake of mine waste with heavy equipment, but on the other hand they claim that the government sloppily leaves clues about what they’re up to — for those clever enough to find them (such as those who misread the Letter to the Editor mentioned above).

And, of course, conspiracy theories abound on the subject of health, with many convinced that doctors and Big Pharma are colluding to keep cancer cures off the market and push disease-causing vaccines on the public for the sake of profits.

Read more at Discovery News