Zebra Stripes Not for Camo, But They Do Something Else

Zebra stripes, besides looking very cool, help to ward off biting flies, a new study finds.

The research, published in Nature Communications, negates the popular theory that zebra stripes evolved for camouflage against predators.

How did the camouflage theory originate in the first place then? Many animals do sport fur, skin, feathers and more that match their environments, making them more difficult to find.

Let's face it, though. Zebras stand out like fashion show supermodels against most any background.

Lead author Tim Caro of the University of California at Davis and colleagues, however, do mention that "humans find moving striped objects difficult to target accurately on a computer screen, suggesting a possible motion dazzle confusion effect."

A running zebra might then puzzle predators, but Caro and his team could find no consistent evidence for that after studying all seven existing wild equid species. (This group includes zebras, along with wild horses and wild asses.) Not all of these animals are striped. Przewalski's horse, for example, is usually solid brown in color.

The researchers determined that the distribution of striped species overlaps with the ranges where biting flies are active. Zebras appear to be particularly sensitive to the flies.

"Biting fly mouth part lengths are markedly longer than average hair depths of zebras and approximately the same as zebra hair lengths, perhaps making zebras particularly susceptible to (biting fly) annoyance," the authors wrote.

Flies don't just irritate zebras either. The flies can spread disease and cause significant blood loss.

As for how the stripes ward off biting flies, the researchers explained, "Biting flies are attracted to hosts by odor, temperature, vision and movement that may act at different stages during host seeking, but vision is thought to be important in the landing response."

The flies are attracted to dark colors, but stripes somehow seem to throw off the visual systems of the biting flies.

Read more at Discovery News

Medieval Poop Found: Still Stinks

A number of Medieval wooden barrels have been uncovered in Denmark, revealing their less- than-glamorous contents.

Originally built to transport goods and store fish, the barrels were converted into latrines — still filled with their original contents.

"We are talking about 700-year-old latrines. And yes, they still smell bad," Maria Elisabeth Lauridsen, the archaeologist in charge of the excavation, told Discovery News.

Unearthed in the center of the Medieval town of Odense, the birthplace of the fairy tale writer Hans Christian Andersen, the barrels are believed to have served a toilet area.

"The excavation is characterized by great conditions for preservation and is located on a Medieval site that has been found to contain brick houses, half-timbered houses and stables," Lauridsen said.

Described as being in "excellent condition," the human excrement can give scientists unique insight into what people ate in Denmark in the Middle Ages.

"Preliminary results of analysis show that raspberries were popular in Odense in the 1300s. The contents also contain small pieces of moss, leather and fabric which were used as toilet paper," Lauridsen said.

It appears that barrels were recycled for various use in Medieval Odense. The excavation unearthed three barrels stacked on top of one another and tied together that served as a basic well.

A system of pipes at the bottom of the structure led water to the well. To prevent mud from getting into the well, the lowest barrel was covered with reeds.

"This well has probably been a part of beer brewing. We have excavated nearby a stock of partially germinated barley which is commonly used in the brewing process," Lauridsen said.

Read more at Discovery News

April Fools! 5 Hilarious Fake Scientific Breakthroughs

#1 Auspicious Alignments

Scientists and science journals are at an advantage when it comes to fooling the rest of the world on April 1. For one thing, the average reader is optimistic, and therefore liable to believe anything amazing when it comes to scientific discoveries. Secondly, no one expects a stereotypically dry, robotic scientist to pull a prank.

Here are our favorite fake scientific breakthroughs -- tall tales that were really told -- from April Fools' Days of the past.

On the first morning in April 1976, BBC Radio 2 astronomer Patrick Moore announced the approach of a once-in-a-lifetime astronomical event. At 9:47 a.m., Moore said, the planet Pluto the would pass directly behind Jupiter, and at that moment their gravitational alignment would counteract and thus lessen the pull of Earth's gravity. Moore told his listeners that if they jumped in the air at the exact moment of this planetary alignment, they would experience a strange floating sensation. At 9:48, callers flooded the lines of BBC 2 with stories of their brief buoyant experiences.

A flurry of worry about the March 19, 2011 "Supermoon," which people feared would set off earthquakes and other cataclysmic events, showed the public hasn't come very far in its understanding of astronomical influences since the 1976 prank.

#2 Flying Penguins

On April 1, 2008, the BBC played footage of a colony of flying penguins that it claimed had just been discovered on King George Island near Antarctica. In the "mockumentary," former Monty Python star Terry Jones played the David Attenborough-esque guide.

"We'd been watching the penguins and filming them for days, without a hint of what was to come," Jones said. "But then the weather took a turn for the worse. It was quite amazing. Rather than getting together in a huddle to protect themselves from the cold, they did something quite unexpected, that no other penguins can do."

Though penguins can't actually get airborne -- not even when Terry Jones is around -- the mechanics of how they swim are remarkably similar to how birds fly.

#3 Telepathic Tweeting

 The April 1999 edition of Red Herring Magazine, then a successful tech/business publication, included an article about a revolutionary new technology that allowed users to compose and send email messages of up to 240 characters ... telepathically. The article attributed the new development to computer genius Yuri Maldini, who had supposedly created it as a spinoff of the encrypted communications systems he developed for the U.S. Army during the Gulf War. The article even describes an incident when Maldini answered his interviewer's question telepathically, via email. Red Herring received numerous letters from fooled readers.

Telepathic email may not seem as ludicrous now as it did then. Mind-controlled technologies, such as a thought-driven car under development in Germany, are getting a boost in recent years from revolutionary neuroscience research.

 #4 Dragons In Nature

In 1998, the online edition of Nature pulled what may be the most cerebral April Fools' Day prank in history. In an article discussing the debate over the origin of birds, the writer refers to the discovery of "a near-complete skeleton of a theropod [T. rex-like] dinosaur in North Dakota." Dubbed Smaugia volans, paleontologists believe the dino "could have flown."

The skeleton, including rib and neck bones that showed signs of frequent exposure to fire, was supposedly discovered by Randy Sepulchrave of the Museum of the University of Southern North Dakota.

There is no University of Southern North Dakota. That clue-in is straightforward enough, but the other two are less obvious: Smaug was the name of the dragon in JRR Tolkien's “The Hobbit.” And Sepulchrave was the 76th Earl of Groan in Mervyn Peake's Titus Groan. The earl believed that he was an owl, and leapt to his death from a high tower. He discovered too late that he could not fly.

Read more at Discovery News

Gravitational Wave Discovery Might Not Have Inflation Origin

Last month, astrophysicists announced a groundbreaking discovery: compelling evidence for gravitational waves had been found and the source of these waves might be the inflationary period just after the Big Bang.

Compelling the evidence may be, but could there be another explanation?

In a paper submitted to the arXiv preprint archive last week, a trio of theoretical physicists pushed back on the historic Cosmic Extragalactic Polarization 2 (BICEP2) finding, suggesting that there may be another source of the gravitational waves: What if they weren’t generated during the rapid period of inflation?

First, let’s rewind a little. What is inflation and how are gravitational waves strong evidence of its occurrence?

In a nutshell, when the BICEP2 researchers detected polarized ripples in the cosmic microwave background (CMB) radiation, the signal strongly matched theoretical predictions as to what gravitational waves should look like. Until now, gravitational waves — that Einstein theorized during the formulation of his bedrock theory of general relativity nearly 100 years ago — have been maddeningly difficult to detect. So, at first glance, the BICEP2 finding is a historic one; this is strong observational evidence for gravitational waves, a fact that no scientist is disputing.

But how did these gravitational waves end up being etched into the CMB? This is the point of contention.

The CMB exists right at the very limit of our observational capabilities. Widely regarded as the “echo” of the Big Bang, which occurred nearly 14 billion years ago, we can analyze the very slight temperature fluctuations in the CMB (known as “anisotropies”) to gain an insight to the structure of the Universe just after the Big Bang.

For the Universe to exist in its current scale and for it to have been spawned from a point, however, cosmologists believe the Big Bang had to have been followed by an intense period of acceleration. This faster-than-light expansion occurred a billionth of a billionth of a billionth of a millionth of a second after the Big Bang.

For our current understanding of the Universe to hold true, inflation had to occur. This is where the BICEP2 results comes in.

As interpreted by the BICEP2 team, the gravitational wave polarization signature embedded in the CMB suggests that the gravitational waves themselves have inflationary origin. Gravitational waves are generated by the most energetic events in the Universe — from black holes colliding to stars exploding — like ripples traveling across the surface of a pond, these waves travel through spacetime at the speed of light.

Inflation theory researchers also believe that primordial gravitational waves may be generated during the most violent event our Universe has ever seen: inflation. And the BICEP2 results certainly point to strong evidence of an inflationary (and quantum) origin of these waves.

However, theoretical physicists James B. Dent (University of Louisiana at Lafayette), Lawrence M. Krauss (Arizona State University, Tempe) and Harsh Mathur (Case Western Reserve University, Cleveland, Ohio) think that the BICEP2 researchers may have overlooked an alternate source of these waves.

“While the Inflationary signal remains the best motivated source (of the gravitational wave signal), the current measurement unfortunately still allows for the possibility that a comparable gravitational wave background might result from a self ordering scalar field transition that takes place later at somewhat lower energy,” the physicists write.

So what does this mean?

After the Big Bang, the Universe was a seething chaotic mess of energy. As the Universe cooled, this energy slowly condensed — like raindrops forming from vapor in clouds — to create the fundamental particles and forces we know and love in our modern epoch. Each particle and force came into existence after each successive “phase change” — but these phase changes weren’t created equal and didn’t occur at the same time across the entire Universe; phase changes occurred in localized pockets.

But at a critical point, when the Universe was cool enough, these pockets are thought to have aligned all at once, “snapping” into place.

Although this critical point phase change across the entire Universe was of a lower energy than the inflationary period that came before it, Dent and co. theorize that it would have created a violent ripple that could have spawned the gravitational waves that BICEP2 is now observing in the CMB.

Read more at Discovery News

Warming climate may spread drying to a third of earth: Heat, not just rainfall, plays into new projections

Increasing heat is expected to extend dry conditions to far more farmland and cities by the end of the century than changes in rainfall alone, says a new study. Much of the concern about future drought under global warming has focused on rainfall projections, but higher evaporation rates may also play an important role as warmer temperatures wring more moisture from the soil, even in some places where rainfall is forecasted to increase, say the researchers.

The study is one of the first to use the latest climate simulations to model the effects of both changing rainfall and evaporation rates on future drought. Published this month in the journal Climate Dynamics, the study estimates that 12 percent of land will be subject to drought by 2100 through rainfall changes alone; but the drying will spread to 30 percent of land if higher evaporation rates from the added energy and humidity in the atmosphere is considered. An increase in evaporative drying means that even regions expected to get more rain, including important wheat, corn and rice belts in the western United States and southeastern China, will be at risk of drought. The study excludes Antarctica.

"We know from basic physics that warmer temperatures will help to dry things out," said the study's lead author, Benjamin Cook, a climate scientist with joint appointments at Columbia University's Lamont-Doherty Earth Observatory and the NASA Goddard Institute for Space Studies. "Even if precipitation changes in the future are uncertain, there are good reasons to be concerned about water resources."

In its latest climate report, the International Panel on Climate Change (IPCC) warns that soil moisture is expected to decline globally and that already dry regions will be at greater risk of agricultural drought. The IPCC also predicts a strong chance of soil moisture drying in the Mediterranean, southwestern United States and southern African regions, consistent with the Climate Dynamics study.

Using two drought metric formulations, the study authors analyze projections of both rainfall and evaporative demand from the collection of climate model simulations completed for the IPCC's 2013 climate report. Both metrics agree that increased evaporative drying will probably tip marginally wet regions at mid-latitudes like the U.S. Great Plains and a swath of southeastern China into aridity. If precipitation were the only consideration, these great agricultural centers would not be considered at risk of drought. The researchers also say that dry zones in Central America, the Amazon and southern Africa will grow larger. In Europe, the summer aridity of Greece, Turkey, Italy and Spain is expected to extend farther north into continental Europe.

"For agriculture, the moisture balance in the soil is what really matters," said study coauthor Jason Smerdon, a climate scientist at Lamont-Doherty. "If rain increases slightly but temperatures also increase, drought is a potential consequence."

Today, while bad weather periodically lowers crop yields in some places, other regions are typically able to compensate to avert food shortages. In the warmer weather of the future, however, crops in multiple regions could wither simultaneously, the authors suggest. "Food-price shocks could become far more common," said study coauthor Richard Seager, a climate scientist at Lamont-Doherty. Large cities, especially in arid regions, will need to carefully manage their water supplies, he added.

Read more at Science Daily

Nanoparticle trapped with laser light temporarily violates second law of thermodynamics

Objects with sizes in the nanometer range, such as the molecular building blocks of living cells or nanotechnological devices, are continuously exposed to random collisions with surrounding molecules. In such fluctuating environments the fundamental laws of thermodynamics that govern our macroscopic world need to be rewritten. An international team of researchers from Barcelona, Zurich and Vienna found that a nanoparticle trapped with laser light temporarily violates the famous second law of thermodynamics, something that is impossible on human time and length scale.

Surprises at the nanoscale

Watching a movie played in reverse often makes us laugh because unexpected and mysterious things seem to happen: glass shards lying on the floor slowly start to move towards each other, magically assemble and suddenly an intact glass jumps on the table where it gently gets to a halt. Or snow starts to from a water puddle in the sun, steadily growing until an entire snowman appears as if molded by an invisible hand. When we see such scenes, we immediately realize that according to our everyday experience something is out of the ordinary. Indeed, there are many processes in nature that can never be reversed. The physical law that captures this behavior is the celebrated second law of thermodynamics, which posits that the entropy of a system -- a measure for the disorder of a system -- never decreases spontaneously, thus favoring disorder (high entropy) over order (low entropy).

However, when we zoom into the microscopic world of atoms and molecules, this law softens up and looses its absolute strictness. Indeed, at the nanoscale the second law can be fleetingly violated. On rare occasions, one may observe events that never happen on the macroscopic scale such as, for example heat transfer from cold to hot which is unheard of in our daily lives. Although on average the second law of thermodynamics remains valid even in nanoscale systems, scientists are intrigued by these rare events and are investigating the meaning of irreversibility at the nanoscale.

Nanoparticles in laser traps

Recently, a team of physicists of the University of Vienna, the Institute of Photonic Sciences in Barcelona and the Swiss Federal Institute of Technology in Zürich succeeded in accurately predicting the likelihood of events transiently violating the second law of thermodynamics. They immediately put the mathematical fluctuation theorem they derived to the test using a tiny glass sphere with a diameter of less than 100 nm levitated in a trap of laser light. Their experimental set-up allowed the research team to capture the nano-sphere and hold it in place, and, furthermore, to measure its position in all three spatial directions with exquisite precision. In the trap, the nano-sphere rattles around due to collisions with surrounding gas molecules.

By a clever manipulation of the laser trap the scientists cooled the nano-sphere below the temperature of the surrounding gas and, thereby, put it into a non-equilibrium state. They then turned off the cooling and watched the particle relaxing to the higher temperature through energy transfer from the gas molecules. The researchers observed that the tiny glass sphere sometimes, although rarely, does not behave as one would expect according to the second law: the nano-sphere effectively releases heat to the hotter surroundings rather than absorbing the heat. The theory derived by the researchers to analyze the experiment confirms the emerging picture on the limitations of the second law on the nanoscale.

Read more at Science Daily

6 New 'Dracula' Ant Species Discovered in Madagascar

Six new species of a mysterious blood-sucking ant have been identified in Madagascar -- and they're an especially odd bunch.

The so-called Dracula ants, described today (March 31) in the journal ZooKeys, seem to defy many of the normal rules that scientists use to classify ants.

"The genus Mystrium is the most mysterious group within the bizarre Dracula ants," study co-author Masashi Yoshimura, a researcher at the California Academy of Sciences, said in a statement. "Mystrium was a difficult group to identify because of the remarkable variation within each species."

The new species include the Mystrium labyrinth, the Mystrium mirror and the Mystrium shadow.

Nonconformists

Dracula ants, so named because they suck the blood of their young in a process dubbed "nondestructive cannibalism," were first discovered in a rotting log in Madagascar more than a decade ago.

But for years, these weird insects confounded researchers, as looks can be deceiving for the Dracula ants.

"The role of an individual in a colony is not always obvious by its appearance. Ants that look similar may be minor workers in one species but queens in another species," study co-author Brian Fisher, an entomologist at the California Academy of Sciences, said in a statement.

For instance, the workers sometimes become queen ants; the queens may have short, nonexistent or large wings; and the queens can often be smaller than the workers. In addition, the genus had three different modes of reproduction, making classification even more difficult.

Mystery solved

After collecting and scrutinizing thousands of the ants in Madagascar for two decades, Yoshimura and Fisher figured out a method for distinguishing new species.

It turned out the ants start out as either a male, a large queen or a major or minor worker, Yoshimura said. Though some of the workers may then go on to reproduce or even become queens, identifying the species requires knowing these origin states, not the current role, of the ant. Classifying them also requires understanding their reproductive style.

Read more at Discovery News

3,300-Year-Old Tomb with Pyramid Entrance Discovered in Egypt

A tomb newly excavated at an ancient cemetery in Egypt would have boasted a pyramid 7 meters (23 feet) high at its entrance, archaeologists say.

The tomb, found at the site of Abydos, dates back around 3,300 years. Within one of its vaulted burial chambers, a team of archaeologists found a finely crafted sandstone sarcophagus, painted red, which was created for a scribe named Horemheb. The sarcophagus has images of several Egyptian gods on it and hieroglyphic inscriptions recording spells from the Book of the Dead that helped one enter the afterlife.

There is no mummy in the sarcophagus, and the tomb was ransacked at least twice in antiquity. Human remains survived the ransacking, however. Archaeologists found disarticulated skeletal remains from three to four men, 10 to 12 women and at least two children in the tomb.

Newly discovered pyramid

The chambers that the archaeologists uncovered would have originally resided beneath the surface, leaving only the steep-sided pyramid visible.

"Originally, all you probably would have seen would have been the pyramid and maybe a little wall around the structure just to enclose everything," said Kevin Cahail, a doctoral student at the University of Pennsylvania, who led excavations at the tomb.

The pyramid itself "probably would have had a small mortuary chapel inside of it that may have held a statue or a stela giving the names and titles of the individuals buried underneath," Cahail told Live Science. Today, all that remains of the pyramid are the thick walls of the tomb entranceway that would have formed the base of the pyramid. The other parts of the pyramid either haven't survived or have not yet been found.

Military ties

It was not uncommon, at this time, for tombs of elite individuals to contain small pyramids, Cahail said. The tomb was excavated in the summer and winter field seasons of 2013 and Cahail will be presenting results at the annual meeting of the American Research Center in Egypt, to be held in Portland, Ore., from April 4-6.

Cahail believes that Horemheb's family had military ties that allowed them to afford such an elaborate tomb. Another burial chamber, this one missing a sarcophagus, contains shabti figurines that were crafted to do the work of the deceased in the afterlife. Writing on the figurines say that they are for the "Overseer of the Stable, Ramesu (also spelled Ramesses)." This appears to be a military title and it’s possible that Ramesu was the father or older brother of Horemheb, Cahail said.

He noted it's interesting that both Horemheb and Ramesu share names with two military leaders, who lived at the same time they did. Both of these leaders would become pharaohs.

"They could actually be emulating their names on these very powerful individuals that eventually became pharaoh, or they could have just been names that were common at the time," Cahail said.

Multiple wives?

The bones the team discovered in the tomb indicate that considerably more women than men were buried in the tomb. This brings up the question of whether Horemheb and Ramesu had multiple wives at the same time. Cahail said that polygamy was a common practice among the pharaohs, but it's uncertain if it was practiced among non-royalty.

Another possibility is that the tomb was used for multiple generations by the same family and contains the remains of daughters, mothers and other female relatives. Yet another possibility is that the tomb was re-used, without permission, at a later date.

Radiocarbon tests, which can provide a date range for the bones, may be done in the future to help solve the mystery.

"You’re left with the question, who are all these people?" Cahail said.

A Jasper treasure

One of the most interesting artifacts the team found was a heart amulet, made of red and green jasper. The hard stone amulet was broken into three pieces.

"It's a beautiful object and possibly one of the best carved examples of these very rare type of amulets," Cahail said. "It was probably on the chest of one of the deceased individuals and there probably would have been some sort of necklaces and gold and things like that."

Read more at Discovery News

Transparent Armor Inspired by Oyster Shell

Two new scientific papers in the last week describe ways to make new kinds of armor that take inspiration from humble mollusks: the abalone and the windowpane oyster. Researchers for both teams, one from France the other from MIT, say they don’t think it will be long before soldiers, and perhaps our cars, will be outfitted bio-inspired armor, windshields or heat shields.

“There is so much going on right now, the advances in the next decade are going to be incredible,” said Christine Ortiz, professor of materials science and engineering at MIT. Ortiz and graduate student Ling Li have a study in today’s edition of the journal Natural Materials describing experiments with a species of oyster (Placuna placenta) that has a shell that is 99 percent ceramic and 80 percent transparent. That’s a pretty good combination for a bullet-proof windshield, explained Ortiz.

“When we started doing mechanical tests we found it has multi-hit capability,” Ortiz said. And, unlike glass, when the researchers penetrated the oyster shell with a tiny sharp object, the shell didn’t fracture and the deformation was localized.

Obviously, an 80 percent clear windshield isn’t good enough to see through. But that’s because the windowpane oyster doesn’t need to be transparent, just blend in with the sandy sea bottom. The next step is to replicate the structure of the oyster shell with another material.

“How do you make a nano-composite in the structure with an anti-ballistic ceramic?” Ortiz said.

At the French National Center for Scientific Research (CNRS/Saint-Gobain), Sylvain Deville has come up with a unique method of using the substance secreted on the insides of shells called mother-of-pearl, or nacre, for another kind of bio-inspired armor. Deville’s work was published March 23 in the same journal, Nature Materials, and uses the structure of ice crystals as a template for building the armor.

“For armor, nacre is the real standout for everyone,” Deville said from his lab in Cavaillon, France. “It’s so good for absorbing energy.”

Read more at Discovery News

Seeds of Monster Black Holes Were Surprisingly Big

The gigantic black holes that lurk at the hearts of galaxies were apparently born big.

The central black holes in dwarf galaxies — the "seeds" that grow into the monsters at the core of the Milky Way and other large galaxies — are probably surprisingly weighty, containing 1,000 to 10,000 times the mass of our sun, a new study reports.

The finding goes against one popular theory of supermassive black hole evolution, suggesting that galaxy mergers aren't necessary to create these behemoths, which can harbor billions of times more mass than the sun.

"We still don't know how the monstrous black holes that reside in galaxy centers formed," lead author Shobita Satyapal, of George Mason University in Virginia, said in a statement. "But finding big black holes in tiny galaxies shows us that big black holes must somehow have been created in the early universe, before galaxies collided with other galaxies."

It's also possible that supermassive black holes grow primarily by gobbling up gas and dust, getting bigger relatively sedately along with their host galaxies, researchers said.

Satyapal and her colleagues analyzed observations of dwarf galaxies made by NASA's Wide-field Infrared Survey Explorer spacecraft, or WISE.

Dwarf galaxies have changed relatively little over time, and they resemble the types of galaxies that existed when the universe was young. So they're a good place to look for nascent supermassive black holes, researchers said.

WISE's all-sky survey picked out hundreds of dwarf galaxies, which appear to sport strikingly large black holes.

"Our findings suggest the original seeds of supermassive black holes are quite massive themselves," Satyapal said.

While the results are intriguing, follow-up study will be necessary to fully flesh them out, outside researchers said.

"Though it will take more research to confirm whether the dwarf galaxies are indeed dominated by actively feeding black holes, this is exactly what WISE was designed to do: find interesting objects that stand out from the pack," astronomer Daniel Stern, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. Stern was not part of the study team.

Read more at Discovery News