Oct 26, 2013

Scientists Solve Mystery of Odd Patterns of Oxygen in Solar System's Earliest Rocks

Cosmochemists have solved a long standing mystery in the formation of the solar system: Oxygen, the most abundant element in Earth's crust, follows a strange, anomalous pattern in the oldest, most pristine rocks, one that must result from a different chemical process than the well-understood reactions that form minerals containing oxygen on Earth.

"Whatever the source of the anomaly must be a major process in the formation of the solar system, but it has remained a matter of contention," said Mark Thiemens, dean of the University of California, San Diego's division of physical sciences and professor of chemistry. "Our experiments essentially recreate the early solar system in that they take gas phase molecules and make a solid, a silicate that is essentially the building block of planets."

By re-creating conditions in the solar nebula, the swirl of gas that coalesced to form our star, the planets and the remnant rocky debris that circles the Sun as asteroids, the researchers demonstrated that a simple chemical reaction, governed by known physical principles, can generate silicate dust with oxygen anomalies that match those found in the oldest rocks in the solar system, they report in the early online edition of Science October 24.

Scientists first noted the discrepancy forty years ago in a stony meteorite that exploded over Pueblito de Allende, Mexico, and it has been confirmed in other meteorites as well. These stony meteorites, asteroids that fell to Earth, are some of the oldest objects in the solar system, believed to have formed nearly 4.6 billion years ago with the solar nebula's first million years. The mix between oxygen-16, the most abundant form with one neutron for each proton, and variants with an extra neutron or two, is strikingly different from that seen in terrestrial rocks from Earth, its moon and Mars.

"Oxygen isotopes in meteorites are hugely different from those of the terrestrial planets," said Subrata Chakraborty, a project scientist in chemistry at UC San Diego and the lead author of the report. "With oxygen being the third most abundant element in the universe and one of the major rock forming elements, this variation among different solar system bodies is a puzzle that must be solved to understand how the solar system formed and evolved."

Oxygen isotopes usually sort out according to mass: oxygen-17, with just one extra neutron, is incorporated into molecules half as often as oxygen-18, with two extra neutrons. In these stony meteorites though, the two heavier oxygen isotopes show up in equal proportions. The rates at which they are incorporated into minerals forming these earliest rocks was independent of their masses. Thiemens and John Heidenreich demonstrated such mass-independent fractionation of oxygen isotopes in the formation of ozone thirty years ago, but the mechanism for a similar process in forming the solid building blocks of rocks has not be demonstrated experimentally before now.

Indeed, several competing ideas have been put forth as potential explanations for the anomaly. Some have suggested that the mix of oxygen isotopes was different back when the earliest solid matter in the solar system formed, perhaps enriched by matter blasted in from a nearby supernova. Others had proposed a photochemical effect called self-shielding, which this team has previously ruled out. The last-standing idea was that a physical chemical principle called symmetry could account for the observed patterns of oxygen isotopes.

To test that idea, Chakraborty filled a hockey puck sized chamber with pure oxygen, varying amounts of pure hydrogen and a little black nugget of solid silicon monoxide. He used a laser to vaporize a plume of silicon monoxide gas into the mix. These are ingredients seen by radiotelescopes in instellar clouds, the starting point for our solar system.

The silicon monoxide gas reacted with the oxygen and hydrogen to form silicon dioxide, a solid that settled as dust in the chamber and is the basis of silicate minerals like quartz that are so prevalent in the crust of Earth. These reactions of gases formed the earliest solid materials in the solar system.

When Chakraborty and Petia Yanchulova, a physics student and co-author of the paper, collected and analyzed the dust, they saw a mix of oxygen isotopes that matched the anomalous pattern found in stony meteorites. The degree of the anomaly scaled with the percentage of the atmosphere that was hydrogen, an observation that points to a reaction governed by symmetry.

Read more at Science Daily

Monkey That Purrs Like a Cat Is Among New Species Discovered in Amazon Rainforest

At least 441 new species of animals and plants have been discovered over a four year period in the vast, underexplored rainforest of the Amazon, including a monkey that purrs like a cat.

Found between 2010 and 2013, the species include a flame-patterned lizard, a thumbnail-sized frog, a vegetarian piranha, a brightly coloured snake, and a beautiful pink orchid, according to World Wildlife Fund (WWF).

Discovered by a group of scientists and compiled by WWF, the new species number 258 plants, 84 fish, 58 amphibians, 22 reptiles, 18 birds and one mammal. This total does not include countless discoveries of insects and other invertebrates.

"These species form a unique natural heritage that we need to conserve. This means protecting their home -- the amazing Amazon rainforest -- which is under threat from deforestation and dam development," said Claudio Maretti, Leader of Living Amazon Initiative, WWF.

Some of the most remarkable species outlined in the report include:
  • Flame-patterned lizard: This beautiful lizard was found from the hatchlings of eggs collected by scientists in the Colombian Amazon. An elusive species, Cercosaura hypnoides, has not been seen in the wild since the original eggs were collected, raising the prospect that it could potentially be endangered.
  • • Thumbnail-sized frog: This amphibian is already believed to be highly endangered. In fact, its Latin name, Allobates amissibilis, meaning "that may be lost," alludes to this as the area where it thrives could soon be opened to tourism. This is now the third Allobates species found in Guyana.
  • • Vegetarian Piranha: This new species of piranha, Tometes camunani, can span 20 inches wide and weigh up to 9 pounds, and is strictly herbivorous. The freshwater fish inhabits rocky rapids associated with seedlings of plants that grow among the rocks, its main source of food. Tometes is described from the upper drainages of the Trombetas River basin, Para, Brazilian Amazon.
  • • A brightly coloured snake from the "Lost World": Found in the mountains of Guyana, this brightly-colored snake species was named Chironius challenger after Arthur C. Doyle's fictional character Professor George Edward Challenger in the novel, The Lost World.
  • • A beautiful pink orchid: Among the new plant species are a large number of new orchid species, including this splendid pink species, Sobralia imavieirae, officially described by scientists from Roraima in the Brazilian Amazon.
  • • Caqueta titi monkey: This new species, Callicebus caquetensis, is one of about 20 species of titi monkey, which all live in the Amazon basin. The babies have an endearing trait, "When they feel very content they purr towards each other," explained scientist Thomas Defler.
  • Many of the new discoveries are believed to be endemic to the Amazon rainforest and are found nowhere else in the world. This makes them even more vulnerable to rainforest destruction that occurs every minute across the Amazon.
Read more at Science Daily

Oct 25, 2013

Scorpion-Eating Mice Feel No Sting

The sting of the Arizona bark scorpion is so fierce that humans say the pain is like being hit by a hammer. But the tiny grasshopper mouse shakes off the sting like it's nothing.

Now, researchers have found for the mouse, the sting really is nothing. Instead of causing pain, the scorpion venom blocks it, a fact that could lead to the development of new pain-blocking drugs for people.

"The venom actually blocks the pain signal that the venom is trying to send" to the mouse, said study researcher Ashlee Rowe of Michigan State University. "We don't want to try to sound too cute or anything, but it is sort of like an evolutionary martial art, where the grasshopper mice are turning the tables. They're using their opponents' strength against them."

Fierce mouse

Southern grasshopper mice (Onychomys torridus) are carnivorous desert-dwellers. Among their favorite meals are the Arizona bark scorpions (Centruroides sculpturatus). The scorpions' sting would kill any other rodent the size of the grasshopper mouse, but the little rodent can absorb many stings in the course of attacking a scorpion. In studying this phenomenon, Rowe noticed not only did the mice survive, but they also seemed unconcerned.

"I was really intrigued by the fact that the mice, if they get stung, they just groom a little bit and then it's over," Rowe told LiveScience.

Clearly, the mice had evolved to handle the pain. To find out how, Rowe and her colleagues analyzed how the toxin acts on the nerve cells called nociceptors that pick up and relay pain to the mouse's brain.

Nerve cells communicate pain to the brain by translating stimuli into electric pulses. To do so, tiny channels in the cell membrane, called ion channels, open and close. One ubiquitous type of ion channel, the sodium/potassium channel, is present in cells throughout the body. This channel makes critical bodily functions, from breathing to muscle contractions, possible.

Typically, scorpion venom acts directly on sodium/potassium channels in nociceptors to create the sensation of pain. A specialized channel known as channel 1.7 is responsible for picking up the pain signal, whereas a channel called channel 1.8 carries it to the brain.

"They just turn (the nerve) on and send that signal to the brain," Rowe said.

Not so in the grasshopper mouse. In these rodents, the scorpion toxin binds to channel 1.8.

Cutting a wire

By binding to this transport channel, the toxin shuts it down, effectively blocking itself, Rowe and her colleagues report Friday (Oct. 25) in the journal Science.

"It's kind of like cutting a wire," Rowe said.

The finding explains why the mice seem to feel almost no pain when stung. Instead of acting as a painful stimulus, the toxin ends up acting like an analgesic.

Rowe thinks the grasshopper mice may be one of several animals that have evolved to withstand the scorpion's sting. She's currently investigating three possible creatures that might also feel no pain — though she prefers to keep the identities of those animals a secret until further testing. (Rowe won't be forcing scorpion showdowns in the name of this research; rather, she'll do genetic testing to look for signs of venom resistance.)

The ultimate goal of this work is to find new ways to ease pain in humans.

Read more at Discovery News

Arctic Temperatures Highest in 44,000 Years

Plenty of studies have shown that the Arctic is warming and that the ice caps are melting, but how does it compare to the past, and how serious is it?

New research shows that average summer temperatures in the Canadian Arctic over the last century are the highest in the last 44,000 years, and perhaps the highest in 120,000 years.

"The key piece here is just how unprecedented the warming of Arctic Canada is," Gifford Miller, a researcher at the University of Colorado, Boulder, said in a joint statement from the school and the publisher of the journal Geophysical Researcher Letters, in which the study by Miller and his colleagues was published online this week. "This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gases in the atmosphere."

The study is the first to show that current Arctic warmth exceeds peak heat there in the early Holocene, the name for the current geological period, which began about 11,700 years ago. During this "peak" Arctic warmth, solar radiation was about 9 percent greater than today, according to the study.

Miller and his colleagues gauged Arctic temperatures by looking at gas bubbles trapped in ice cores (cylinders drilled from the ice that show layers of snow laid down over time) taken from the region, which allows scientists to reconstruct past temperature and levels of precipitation. They paired this with radiocarbon dating of clumps of moss taken from a melting ice cap on Canada's Baffin Island. Their analysis shows that these plants have been trapped in the ice for at least 44,000 years, and perhaps as long as 120,000 years. Taken together, that data suggest temperatures in the region haven't been this high since perhaps as long as 120,000 years ago, according to the study.

Read more at Discovery News

Face-Shape Secrets May Lie in 'Junk' DNA

Face shape is largely determined by genetics, yet no two faces are entirely alike. How do genes bring about faces with subtle differences while avoiding dramatic disruptions and facial malformations such as cleft lip and palate? The answer may be in the "junk DNA," a new study has found.

Noncoding DNA, sometimes called junk DNA, refers to sequences in a genome that don't produce proteins, some of which are thought to have no known biological function.

Studying mice, researchers identified more than 4,000 small regions in the genome that are likely a type of noncoding DNA called enhancers, which amplify the expression of a gene. In this case, these regions were active while the face of a mouse embryo developed, according to the study, detailed in the Oct. 25 issue of the journal Science.

Most of these enhancer sequences are found in humans as well, so it is likely that they have similar face-shaping functions in humans, the researchers said.

"Our results suggest it is likely there are thousands of enhancers in the human genome that are somehow involved in craniofacial development," study researcher Axel Visel, a geneticist at Lawrence Berkeley National Laboratory's genomics division, said in a statement. "We don't know yet what all of these enhancers do, but we do know that they are out there and they are important for craniofacial development."

To test whether these enhancers are indeed important in shaping the face, the researchers deleted three of the enhancers in mice and compared them with normal mice at 8 weeks of age. The results showed that each enhancer deletion caused a distinct set of differences in the shape of the face -- for instance, causing an increase or decrease in facial length and an increase or decrease in the width of various parts of the face, such as the base of the skull or the palate.

In the study, to avoid the challenge of recognizing individual mouse faces, the researchers created 3D images using a process called microcomputed tomography to link changes in face shape with alterations in the function of each of the enhancers.

Identifying enhancers that regulate a gene's activity is challenging, because such enhancers aren't necessarily located next to their target gene; rather, they could be acting from "long-distance" locations in the genome.

Many of the genetic defects that cause facial flaws such as clefts of the lip or palate have been identified, but only a small number of genes have been implicated in normal variation of the face's shape, the researchers said.

Read more at Discovery News

This Is The Coldest Place In The Universe

As October progresses and winter slowly but surely approaches in the Northern Hemisphere, trees begin to lose their leaves and temperatures steadily drop. Think it’s been getting cold out at night where you live?

It’s nothing like this.

At a positively frigid one Kelvin (that equates to –458 degrees Fahrenheit or –272 degrees Celsius), the Boomerang Nebula in the constellation Centaurus is officially the coldest known place in the entire Universe. It’s even colder than the background temperature of space!

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, astronomers have taken a better look at this freezing cloud of gas and dust to learn more about its frigid properties.

The Boomerang Nebula has been imaged before by both ground-based telescopes and the Hubble Space Telescope, and appears in visible light to be shaped like a bow tie (or two opposing, overlapped boomerangs). But new observations using ALMA’s high-resolution capabilities have revealed its true form.

“What seemed like a double lobe, or ‘boomerang’ shape, from Earth-based optical telescopes, is actually a much broader structure that is expanding rapidly into space,” said Raghvendra Sahai, a researcher and principal scientist at NASA’s Jet Propulsion Laboratory and lead author of a paper published in the Astrophysical Journal.

A thick belt of dust particles has also been found – thanks to ALMA – surrounding the star within the nebula, which prevents some wavelengths of light from passing through and creating the bow tie shape seen in previous visible light images.

So why is this nebula so incredibly cold? It’s actually cooling itself off as it grows, astronomers have found.

As the sun-like star at its center nears the end of its life it expands the nebula with rapidly outpouring gas. That expansion creates a cooling effect — similar to how expanding gas in refrigerators helps keep your ice cream from melting.

The gas in this nebula is traveling much faster than anything in your fridge, though — 500,000 km/hour (310,000 mph).

At one Kelvin the Boomerang nebula is even colder than the coldest known places in our solar system: the permanently-shadowed craters at the moon’s south pole that never receive sunlight. Even those pockets of darkness are a balmy 33 Kelvin. (For comparison, water freezes at 273.15 K.)

For that matter, even in the midst of intergalactic space where there’s “nothing” is still warmer — the cosmic microwave background glows at a steady 2.8 K.

Read more at Discovery News

Oct 24, 2013

Ancient Bees, Dinos May Have Died Out Together

The ancestors of modern carpenter bees may have vanished from Earth roughly 65 million years ago, around the same time the dinosaurs were wiped out, a new study finds.

Researchers examined the DNA of four types of carpenter bees -- belonging to the group Xylocopinae -- from every continent, except Antarctica, to search for clues about their evolutionary relationships. Peering back into the lineages of the bees, the scientists noticed something unusual with all four groups, beginning roughly 65 million years ago, at the boundary between the Cretaceous and Paleogene periods.

"We can track periods of diversification and stasis," lead study author Sandra Rehan, an assistant professor of biological sciences at the University of New Hampshire, told LiveScience. "There was a period where there was no genetic diversification happening for millions of years -- a real dearth of speciation. This is an indication of a mass extinction event."

The end of the Cretaceous Period, corresponding to the beginning of the Paleogene Period, was already known to be a dynamic time in history. It is commonly thought that a massive asteroid or comet slammed into Earth 65 million years ago, wiping out the dinosaurs and killing up to 80 percent of all species.

"We found this mass extinction event signature in the DNA that just happened to correspond to the extinction of dinosaurs, which was a major change in the global diversity at the time," Rehan said.

Rehan and her colleagues did not study possible relationships between the bee and dinosaur extinctions, but said the similar timings act as secondary support for both theories.

Since there are no reliable fossil records for carpenter bees, the researchers used a technique called molecular phylogenetics. This involves analyzing DNA sequences and searching through the data for evolutionary insights. To understand where in time evolutionary changes were happening, the researchers used fossils of other types of bees as reference points.

"We used fossils of other lineages of bees to make inferences and calibrate time," Rehan explained. "Then, we backtracked over time."

The new research suggests the bee extinction lasted about 10 million years, she added.

The findings should generate great interest in the field, said John Ascher, assistant professor in the department of biological sciences at the National University of Singapore and a research associate in the division of invertebrate zoology at the American Museum of Natural History in New York City. But Ascher, who wasn't involved in the current research, said studies that use molecular phylogenetics tend to be "speculative in their reliance on unrealistic and insufficiently justified evolutionary models."

Read more at Discovery News

Ancient Magic Curse Tablet Found in Jerusalem

A lead curse tablet, dating back around 1,700 years and likely written by a magician, has been discovered in a collapsed Roman mansion in Jerusalem, archaeologists report.

The mansion, which is being excavated by the Israel Antiquities Authority in the Givati Parking Lot, is located in what is known as the "City of David," an area that holds at least 6,000 years of human occupation. The mansion itself covers at least 2,000 square meters (about half an acre) and contains two large open courtyards adjacent to each other. It was in use between the late third century and A.D. 363, when it was destroyed in a series of earthquakes on May 18 or 19.

The text is written in Greek and, in it a woman named Kyrilla invokes the names of six gods to cast a curse on a man named Iennys, apparently over a legal case.

"I strike and strike down and nail down the tongue, the eyes, the wrath, the ire, the anger, the procrastination, the opposition of Iennys," part of the curse reads in translation. Kyrilla asks the gods to ensure that "he in no way oppose, so that he say or perform nothing adverse to Kyrilla … but rather that Iennys, whom the womb bore, be subject to her…"

To obtain her goal Kyrilla combined elements from four religions, Robert Walter Daniel, of the Institut für Altertumskunde at the University of Cologne, told LiveScience in an email. Of six gods invoked, four of them are Greek (Hermes, Persephone, Pluto and Hecate), one is Babylonian (Ereschigal) and one, Abrasax, is Gnostic, a religion connected to early Christianity. Additionally, the text contains magic words such as "Iaoth" that have a Hebrew/Judaism origin.

A professional magician likely created the curse for Kyrilla, who may have literally used a hammer and nails to perform a magical rite that enhanced the effectiveness of the curse, Daniel said.

"The hammering and nailing is a form of gaining control over the person(s) targeted in magical texts," he wrote in the email.

Kyrilla and her curse-recipient, both probably members of the Roman middle or upper class, were likely in some legal dispute, as the curse tablet bears similarities to others found in Cyprus that are known to have been used in legal cases. Additionally the word "opposition" in this text hints at a legal matter.

Exploring the mansion

The newfound artifacts hint at the wealth the occupants of the mansion would have enjoyed and include a miniature head of a fighter used as a scale-weight and several gems, including one engraved with an image of Cupid holding a torch.

The tablet was excavated in the northwest part of the mansion. While the second-floor room where the tablet was originally placed has collapsed, the artifacts excavated near the tablet provide hints about what the room may have looked like when in use.

Archaeologists Doron Ben Ami and Yana Tchekhanovets, both with the Israel Antiquities Authority, told LiveScience in an email they discovered the remains of mosaics and frescos that contain geometric and floral motifs near the tablet. They also found carved bone fragments from a box that depict the "Triumph of Dionysus," a Greek god, along with maritime imagery such as seahorses.

The team also uncovered roof tiles in the mansion that contain the stamp of the Roman 10th legion, a unit that, for a time, was stationed in Jerusalem. "This practice is common for all the provinces of the Roman Empire. In peaceful times soldiers were responsible for 'civil engineering': They built roads and aqueducts, produced tiles and bricks, etc. The 10th legion produced so many tiles, that it was enough for many more years of construction activity in the city, long after the legion itself left Jerusalem," Ben Ami and Tchekhanovets said.

The researchers also found female figurines, probably depicting a goddess. They were likely used in a "private cult" whose members included residents of the mansion. These figurines were found at or below floor level and may not have been part of the second-floor room that the curse was placed in.

Read more at Discovery News

5 Intriguing Facts About the Roma

Their names are as mysterious as their origins: Often called the Roma or the Romani people, they're also known as gitanos in Spain, Kale in Finland and Portugal, Manush or gitan in France and Travelers in Scandinavia.

And almost everywhere they go, they're referred to -- somewhat pejoratively -- as gypsies, a people who have migrated throughout the world over the course of several centuries.

The Roma have one of the most dramatic stories in human history, but few people know their ancient tale of travel, persecution and survival. Here are five intriguing facts about the Romani people:

1. The Roma originated in India

There's a wealth of evidence -- from genetics as well as linguistics -- that the Roma are originally a Hindi people from northern India. Many of the words and grammatical rules of the Romani language are virtually identical to those of the Hindi language.

A 2012 study, published in the journal Cell Biology, analyzed genomic data from 13 Romani communities across Europe. The researchers concluded that the Roma people left northern India about 1,500 years ago; those Roma now in Europe migrated through the Balkans starting about 900 years ago. These data confirm written reports of Roma groups arriving in medieval Europe in the 1100s.

2. There are about 12 million Roma worldwide

After leaving northern India, most Romani went to Europe: In some Eastern European countries, such as Romania and Bulgaria, they form up to 12 percent of the total population. The Roma are also numerous in Turkey, which has about 2.75 million Romani, according to The New York Times: Other European countries with large Roma populations include Russia, Slovakia, Hungary, Serbia, Spain and France.

Though concentrated in Europe, there are also Romani populations on every occupied continent -- about 1 million live in the United States, and roughly 800,000 in Brazil. But no matter where they go, the Roma seem to be unwelcomed.

3. The Romani faced horrific persecution

Shortly after arriving in Europe, the Romani were enslaved in many regions, a cultural heritage that continued into the 19th century in countries like Romania. In England, Switzerland and Denmark, the Romani were put to death throughout the medieval era. Many countries, such as Germany, Italy and Portugal, ordered the expulsion of all Romani.

There are countless reports of Roma children being abducted from their parents, women who had their ears cut off, and Romani who were branded with hot irons. In an effort to force assimilation, the use of their native language was forbidden in some countries; other places forbade the Roma to marry among themselves.

Perhaps the most devastating persecution of the Romani occurred during World War II, when they were among the first targets of Nazi atrocities, according to the BBC. An estimated 2 million Romani died in concentration camps and through other means of extermination.

In the post-war era, the Romani remained an oppressed group, especially in the Soviet Union. As recently as the 1980s, Roma women in Czechoslovakia were forced to undergo sterilization to limit the Romani population.

4. Roma culture is a rich and fascinating collage

The Romani are often celebrated for their musical heritage, which has influenced jazz, bolero, flamenco music, as well as classical composers including Franz Liszt.

While it's believed that the Roma were originally Hindu, over the centuries, most Romani have adopted the religions of their host countries. The majority of Roma communities now practice a form of Islam or Christianity that retains some Romani influences.

Traditional Roma society still arranges marriages between minors as young as 12, according to the BBC. Teenage brides are sometimes bartered and traded between Roma communities, an activity that has alarmed European officials concerned with human trafficking.

A 2006 report by the Organization for Security and Cooperation in Europe (OSCE) also found that some Roma communities practice child trafficking; children have reportedly been engaged for labor, petty crime and sexual exploitation.

5. The Romani remain an oppressed group

Many Romani avoid assimilation with the larger societies of their host countries -- this may be a legacy of centuries of persecution. Because of their isolation, many Roma children do not attend school; Romani typically lack access to stable jobs, affordable housing, health care and other social services. As a result, poverty, disease, substance abuse and crime plague many Roma communities.

For these and other reasons, the Romani remain a persecuted minority, including those living in affluent European countries with enviable social services. Authorities in Italy have denied housing to Roma families -- even those born in Italy -- on the grounds that people living in cheap, makeshift metal containers in isolated Roma camps already have permanent housing, according to the Guardian.

This month, protests erupted in France after authorities detained a Roma teenage girl at school; soon thereafter, she and her entire family were deported to Kosovo. In the past year, about 10,000 Roma were expelled from France after their camps were destroyed, according to the Baltimore Sun.

Read more at Discovery News

Frontier Fields: Hubble Lens to Get Superboost

Hoping to get a sneak peak at the early universe NASA’s James Webb Space Telescope is expected to reveal, astronomers are attempting to boost the imaging prowess of the Hubble Space Telescope by taking advantage of naturally occurring zoom lenses in space.

The three-year Hubble Frontier Fields project will make use of the light-bending gravity of six massive galaxy clusters to probe for dimmer, more distant objects behind them.

“You put a bunch of mass in the way of some distant galaxies and it actually magnifies them and makes them easier to see,” astronomer Steven Finkelstein, with University of Texas at Austin, told Discovery News.

It’s a bit of a fishing expedition since astronomers have only vague (if any) hints of what lies beyond the six galaxy clusters selected as targets for the study.

The clusters were selected in part because they lie within viewing range of the Atacama Large Millimeter/submilliter Array, or ALMA, observatory in Chile, the Keck Observatory in Hawaii and other telescopes that will be needed to confirm any objects uncovered by the Hubble probe.

Working with nature’s gravitational lenses isn’t easy, however.

“You don’t automatically know when you look at a galaxy that’s been magnified how much it’s magnified by,” astronomer Jennifer Lotz, with the Space Telescope Science Institute in Baltimore, told Discovery News.

“You have to understand what that cluster is doing. You have to understand the optics of the natural telescope, which means you have to have a model of what’s going on in the cluster, how massive it is, and so forth. We’ve done that,” Lotz said.

The gravitational lenses should at least triple Hubble’s imaging powers. In some cases, it could bring objects into view that are 10 times beyond what Hubble can see.

Read more at Discovery News

Oct 23, 2013

Vacuums Provide Solid Ground for New Definition of Kilogram

Of all the standard units currently in use around the world, the kilogram -- the official unit of mass in the International System of Units (SI) -- is the only one that still relies on a physical object for its definition. But revising this outdated definition will require precise vacuum-based measurements that researchers are not yet able to make, said Patrick Abbott of the National Institute of Standards and Technology (NIST) in Gaithersburg, Md. Abbott will present an overview of current efforts in vacuum technology to redefine the kilogram at the AVS 60th International Symposium and Exhibition, held Oct. 27-Nov. 1, 2013, in Long Beach, Calif.

Abbott will also describe his NIST team's development of a novel system to allow a direct comparison of an object being weighed in a vacuum to one outside a vacuum. "Ours is the only project of its type in the world," Abbott said of his team's work, "and we believe that it will be critical in the accurate dissemination of the redefined kilogram."

The official kilogram, called the International Prototype Kilogram (IPK), is stored in a bureau just outside of Paris, France, and has served as the standard to which all the nations' prototypical kilograms have been compared for the last 125 years. Every few decades, the national prototypes are carried, usually by hand, to France, where they are measured against the IPK.

But discrepancies between the national prototypes and the official specimen have been increasing at a rate of 0.050 milligrams (mg) every 100 years. And no one knows why.

"It's not really clear if the IPK is getting lighter or the national prototypes are getting heavier," Abbott said. Loss of mass due to wear is unlikely because the IPK is hardly ever taken out of its vault. To address these discrepancies, an international assembly of metrologists -- researchers who study the science of measurement -- decided in 2007 to wean itself off of the prototype and redefine the kilogram using something more reliable: a constant of nature.

The metrologists eventually chose Planck's constant, which describes the relationship between the energy of a photon and the frequency of light it emits. Its value has been measured with a relative uncertainty of between 30x10-9 and 35x10-9. However, to assure agreement between the current IPK system and the Planck-defined kilogram, researchers will need to improve their measurements to a relative uncertainty of 20x10-9. And to get better measurements, they will need the ability to perform state-of-the-art metrology in a vacuum.

Currently, researchers use two types of experiment to measure Planck's constant, and both require vacuums. One method involves determining the number of atoms in a high-purity silicon sphere with a nominal mass of 1 kilogram. The other, called the watt balance, measures the constant by an indirect or "virtual" comparison of mechanical power to electromagnetic power. Using a vacuum ensures that there is no contamination from particles in the air and reduces uncertainty in some of the measurements that are conducted with laser interferometry.

Researchers using the watt balance experiment at national measurement institutes around the world are working to find the materials best suited to measuring Planck's constant with this method. Efforts are also underway to find a level of vacuum that is good enough to get results without being too difficult to build or maintain. So far, researchers are on track to having a new definition of the kilogram by 2018, Abbott said.

While many teams around the world work to improve measurements of Planck's constant, Abbott's group is looking beyond redefinition and toward making these measurements practical.

Read more at Science Daily

Entombed Etruscan Was Expert Embroiderer

Skeletal remains found last month in an untouched Etruscan tomb likely belonged to an aristocratic woman (not a prince, as earlier reported) buried alongside a spear and her sewing needles.

Analysis revealed that a small bronze box found beside the skeleton in Tarquinia contain the needles -- and some thread.

"X-rays showed the perfectly sealed box contains at least five needles, some threads remains and perhaps a sewing reel," Alfonsina Russo, Superintendent archaeologist for Southern Etruria, told Discovery News.

The precious box was found at the feet of the skeleton, along with a large bronze basin and a smaller dish.

According to University of Turin Alessandro Mandolesi, director of the excavation, it was produced by recycling parts of an older artifact, possibly an 8th-7th-century BC shield. It was probably passed down generations until it reached the noble woman.

"This object and its contents identifies the woman as an embroiderer. It is well known the Etruscans were skilled in textile activities. Indeed, several tombs in Tarquinia feature frescoes depicting finely embroidered draperies," Russo added.

A fun-loving and eclectic people, the Etruscans began to flourish around 900 B.C., and dominated much of Italy for five centuries. During the fifth century B.C., as the Romans grew in power, they began to decline. By 300-100 B.C., their civilization eventually became absorbed into the Roman empire.

Since their puzzling, non-Indo-European language was virtually extinguished (they left no literature to document their society), the Etruscans have long been considered one of antiquity's great enigmas.Much of what we know about them comes from their cemeteries. Only the richly decorated tombs they left behind have provided clues to fully reconstruct their history.

Blocked by a perfectly sealed stone slab for 2,600 years, the small vaulted chamber also contained the partially incinerated remains of another individual.

Anthropological examination suggested the remains might belong to the real warrior prince -- a male aged between 20-30 years. It also confirmed the skeleton's female gender.

Indeed, it was normal for the Etruscans to have a burial for a woman, while the warrior was cremated, as a sign of respect.

The location of the newly discovered tomb on the flank of an imposing mound, the Queen Tomb, explains the aristocratic status of both the woman and the incinerated male, said the archaeologists.

Dating to the 7th century B.C., the mound is the largest among the more than 6,000 rock cut tombs (200 of them are painted) that make up the necropolis in Tarquinia. The closeness to the imposing Queen Tomb, in an area that would have been off limits to ordinary people, suggests the tomb’s occupants were somehow related to the high status elite class of Tarquinia.

According to Mandolesi, the role of the spear, which prompted conjectures about the existence of an Etruscan "warrior princess," can be explained by looking at similar examples in Etruscan and Latin tombs from the same age, the so-called Orientalizing period (due to the influence on the Etruscans from the Eastern Mediterranean.)

"The spear was placed along the woman's body as a symbol of union with the incinerated male. It highlighted her aristocratic status and the close family relationship with the cremated remains," Mandolesi told Discovery News.

Read more at Discovery News

How Genetic Siblings Can Look So Very Different

Recent stories in the news about blond children being found in dark-haired and dusky-skinned Romany families -- children that weren't biological offspring -- prompted us to ask: Is it possible for two children from the same family to look completely different? It turns out the answer is, yes, it is possible. Here's how.

Nature is absolutely amazing when it comes to reproduction. There is a system specifically designed to make children different.

A person has a set of chromosomes. Each chromosome contains two halves that join in the middle so they look like an "X." All that a chromosome is, by the way, is two very tightly coiled strands of DNA (deoxyribonucleic acid).

The two halves of each chromosome come from the two parents. One half of the "X" in each chromosome comes from the mother, and the other half comes from the father. The two halves are bonded together at the middle of the "X." Each half of the "X" contains a complete set of genes, so each chromosome has two copies of every gene -- the "dominant" gene of the two is the one that is expressed.

A sperm and an egg meet to create a new person. The sperm carries one half of the new person's ultimate chromosomes, and the egg contains the other half.

The question then comes down to, "Where does the DNA in the sperm and the egg come from?" Every cell in the father contains a complete set of X-shaped chromosomes that are exactly alike. Same for the mother. The father's chromosomes came from his mother and father, and the mother's from her mother and father. To make a sperm cell, only one half of the X is contributed. But which half? This is where nature does the especially amazing part. When forming sperm cells, the father's body randomly chooses genes from the two halves of the father's chromosomes. This means that every sperm cell contains a random mix of the father's parents' genes. The same thing happens when forming eggs. Therefore, each child that a couple produces is a random mix of the four grandparents' genes.

From Discovery News

Hubble Spots Ancient Galaxy From Dawn of Time

Scientists on the hunt for the first galaxies formed after the universe’s creation have a new milestone -- an unexpectedly active galaxy that existed just 700 million years after the Big Bang.

The long-distance champ, known by its catalog number z8_GND_5296, first revealed itself in the Hubble Space Telescope’s infrared camera. Follow-up investigations with a new infrared light-splitting spectrograph at the Keck Observatory confirmed the galaxy’s location.

“If you tried to look at these really distant galaxies with a visible light telescope you would see nothing. Literally, they’re invisible. All that visible and optical light has been shifted into the near-infrared,” astronomer Steven Finkelstein, with the University of Texas at Austin, told Discovery News.

The shift, known as the Dopper effect, is due to the expansion of the universe and the speed at which the galaxies are moving away. It is similar to the shifting sound of an approaching train.

Oddly, z8_GND_5296 was the only one of 43 galaxy candidates that clearly radiated the telltale chemical fingerprint of a particular hydrogen emission astronomers needed for their celestial measuring sticks.

That in and of itself is fodder for a host of questions about the universe’s early years, particularly when and how quickly photons of light from the first galaxies could navigate intergalactic hydrogen gas without being scattered.

For light to be detected, the hydrogen needs to be ionized, a phenomenon that, somewhat paradoxically, is believed to have been triggered by the first generation of galaxies.

“To look at galaxies that are very distant is particularly interesting because light travels at a finite speed, so essentially the more distant a galaxy is the more time the light takes to get toward us. This means that by looking at distant galaxies we can probe the past history of the universe. We essentially see the galaxy at the point in time when the light was emitted,” astronomer Dominik Riechers, with Cornell University, told Discovery News.

“This galaxy is so far away that any light we receive from it travels for 13.1 billion years before it reaches us. What we’re really seeing is the universe as it looked like 13.1 billion years ago, which is only 700 million years of the Big Bang,” he said.

Aside from confirming z8_GND_5296’s extreme distance, the galaxy turned out to be producing stars at prodigious rate, pumping out the equivalent of 330 masses the size of the sun every year. That is more than 100 times the rate of star formation of the Milky Way galaxy.

“The early universe may harbor a larger number of intense sites of star formation that expected,” Finkelstein wrote in a paper published in this week’s Nature.

He and colleagues also were surprised by the galaxy’s unexpectedly high percentage of oxygen and other so-called metals -- elements heavier than hydrogen and helium.

The related discovery, made with NASA’s Spitzer space telescope, suggests that z8_GND_5296 contains the exploded remains of massive stars, whose nuclear furnaces forged the heavier elements, or that the area of space where the galaxy formed already was seeded with metals from a prior generation of stars -- perhaps the universe’s first.

“It’s surprising that so close to the Big Bang it’s already formed a decent fraction of its metal,” Finkelstein said.

The galaxy is about 1.3 billion times the mass of the sun and located in the direction of the constellation Ursa Major.

Previously, the most distant galaxy was one that formed about 740 million years after the Big Bang.

Read more at Discovery News

Oct 22, 2013

Long-Sought Pattern of Ancient Light Detected

The journey of light from the very early universe to modern telescopes is long and winding. The ancient light traveled billions of years to reach us, and along the way, its path was distorted by the pull of matter, leading to a twisted light pattern.

This twisted pattern of light, called B-modes, has at last been detected. The discovery, which will lead to better maps of matter across our universe, was made using the National Science Foundation's South Pole Telescope, with help from the Herschel space observatory.

Scientists have long predicted two types of B-modes: the ones that were recently found were generated a few billion years into our universe's existence (it is presently 13.8 billion years old). The others, called primordial, are theorized to have been produced when the universe was a newborn baby, fractions of a second after its birth in the Big Bang.

"This latest discovery is a good checkpoint on our way to the measurement of primordial B-modes," said Duncan Hanson of McGill University in Montreal, Canada, lead author of the new report published Sept. 30 in the online edition of Physical Review Letters.

The elusive primordial B-modes may be imprinted with clues about how our universe was born. Scientists are currently combing through data from the Planck mission in search of them. Both Herschel and Planck are European Space Agency missions, with important NASA contributions.

The oldest light we see around us today, called the cosmic microwave background, harkens back to a time just hundreds of millions of years after the universe was created. Planck recently produced the best-ever full-sky map of this light, revealing new details about of our cosmos' age, contents and origins. A fraction of this ancient light is polarized, a process that causes light waves to vibrate in the same plane. The same phenomenon occurs when sunlight reflects off lakes, or particles in our atmosphere. On Earth, special sunglasses can isolate this polarized light, reducing glare.

The B-modes are a twisted pattern of polarized light. In the new study, the scientists were on a hunt for the kind of polarized light spawned by matter in a process called gravitational lensing, where the gravitational pull from knots of matter distorts the path of light.

The signals are extremely faint, so Hanson and colleagues used Herschel's infrared map of matter to get a better idea of where to look. The researchers then spotted the signals with the South Pole Telescope, making the first-ever detection of B-modes. This is an important step for better mapping how matter, both normal and dark, is distributed throughout our universe. Clumps of matter in the early universe are the seeds of galaxies like our Milky Way.

Astronomers are eager to detect primordial B-modes next. These polarization signals, from billions of years ago, would be much brighter on larger scales, which an all-sky mission like Planck is better able to see.

"These beautiful measurements from the South Pole Telescope and Herschel strengthen our confidence in our current model of the universe," said Olivier Doré, a member of the U.S. Planck science team at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "However, this model does not tell us how big the primordial signal itself should be. We are thus really exploring with excitement a new territory here, and a potentially very, very old one."

Read more at Science Daily

Baby Dinosaur Unearthed by High-Schooler

A dinosaur skeleton discovered by an eagle-eyed high-school student turns out to be the smallest, youngest and most complete duck-billed dinosaur of its kind ever found.

This Cretaceous-era herbivore, Parasaurolophus, walked the Earth some 75 million years ago. The dinosaurs in this genus are best known for their impressive tube-shaped head crests, which may have been used for display or perhaps to amplify the animals' calls. The little specimen, dubbed "Joe," was so young that its crest was a mere bump on its head.

"We now understand a lot more about how Parasaurolophus grew its crest," said Andrew Farke, a paleontologist and curator at Raymond M. Alf Museum of Paleontology in Claremont, Calif.

The museum is affiliated with The Webb Schools, a private high-school campus outside of Los Angeles. The students at the schools participate in paleontology fieldwork as part of their coursework, which is how student Kevin Terris came to discover "Joe" in 2009.

Farke and a group of students were prospecting for fossils in Utah's Grand Staircase-Escalante National Monument, surveying ground Farke had already covered. Terris spotted a little sliver of bone sticking out from under a boulder and alerted Farke, who thought it looked like a piece of dinosaur rib — nice, but not really worth the trouble of excavating.

"We were going to try to see if we could get something better," Farke told LiveScience.

He walked around the other side of the boulder and picked up what looked like a large cobblestone, turning it over in his hands. A dinosaur skull stared back at him.

In light of the skull, Farke thought it wise to go re-check Terris' discovery. A closer look revealed it to be a string of toe bones.

"We have the skull on one side of this boulder and the toes on the other side. That means the whole dinosaur skeleton has to be in between," Farke said. "So we got pretty excited."

The team had to line up permits to excavate on the public land; they returned in 2010 to dig the bones from the ground. Surrounded by an 800-pound (363 kilograms) armor of rock, the bones had to be airlifted out of the rugged backcountry by helicopter.

After 1,300 painstaking hours of cleaning, chiseling and picking, technicians revealed the fossil buried in all that stone. The completeness of the skeleton turned out to be "pretty spectacular," Farke said.

The paleontologists realized they had an amazing example of a baby Parasaurolophus on their hands. Even better, they were able to sample the baby's leg bone. As dinosaur bones grow, they develop ring patterns, much like trees.

"It didn't have any rings at all," Farke said of "Joe." "So what that shows is that this animal was under a year old when it died."

The infant dinosaur was already 6 feet (1.8 meters) long, however, an impressive feat when you consider that duck-billed dinos hatched at about the same size as a human infant. The fact that "Joe" was already sprouting a crest bump so young suggests that Parasaurolophus started growing its crest earlier than other duck-billed dinosaurs.

"It finally lets us understand how Parasaurolophus evolved that big crest, just by shifting around events in its development," Farke said.

Read more at Discovery News

Gold Particles Found in Tree Tissue

Trees may turn golden for reasons that have nothing to do with the onset of autumn: Eucalyptus trees can hold grains of gold, potentially helping reveal buried treasure, scientists now find.

Many plants root deep into the Earth, drawing up nutrients and minerals they need for life. Researchers hope this fact could one day help miners unearth gold, especially since discoveries of new deposits of the precious metal have dropped 45 percent over the last 10 years.

Scientists in Australia focused on eucalyptus trees, since traces of gold are sometimes found in soils surrounding these plants. However, researchers were not certain until now whether trees could actually absorb the precious metal from underground deposits or if the wind simply blew gold dust there from other sites.

Now one group has discovered the first evidence in nature of gold particles located within living tissue from trees.

Researchers investigated leaves, twigs and bark of eucalyptus trees up to 35 feet (10 meters) tall from two locations in Australia — one in the west, another in the south. Past exploratory drilling revealed these sites had gold buried underground, but the areas were undisturbed by further mining activity that might have contaminated the trees with gold dust.

X-ray analysis revealed gold particles up to about 8 microns wide in cells from the trees, or about 10 times thinner than the average human hair. Field samples and greenhouse experiments suggest these gold particles — which exist at concentrations not harmful to the trees — are absorbed by the roots and transported to its extremities, such as leaves, where the highest concentrations were observed.

These findings, detailed online Oct. 22 in the journal Nature Communications,suggest the trees could tap into gold deposits up to 115 feet (35 meters) below them while searching for water under drought conditions.

"We were astounded at the capability of the eucalyptus trees to bring up gold from the equivalent of a 10-story building,"study lead author Melvyn Lintern, a geochemist at the Commonwealth Scientific and Industrial Research Organization in Australia, told LiveScience's OurAmazingPlanet.

Read more at Discovery News

Exoplanet Count Blasts Through the 1,000 Barrier

Hunting for signs of extrasolar planets — or exoplanets — is hard, but counting them can also prove tricky. Today, however, our historic era of exoplanetary discovery has turned into a red letter day; the first 1,000 exoplanets to be confirmed have been added to the Europe-based Extrasolar Planets Encyclopaedia.

For the last few weeks, astronomers (and the science media) have been waiting with bated breath as the confirmed exoplanet count tallied closer and closer to the 1,000 mark. Then, with the help of the Super Wide Angle Search for Planets (SuperWASP) collaboration, the number jumped from 999 to 1,010 overnight.

The 11 new additions may be noteworthy as breaking the 1,000 barrier, but they’re certainly not noteworthy as being anything remotely habitable. All 11 scoot around their parent stars with periods of between 8 and less than 2 days — making all of these new confirmed worlds “hot-Jupiters.”

Keeping a tally of exoplanets isn’t as easy as it seems. Although the Extrasolar Planets Encyclopaedia has been updated, it may be some time until other exoplanetary lists are updated. For example, NASA’s Jet Propulsion Laboratory keeps its own record called the Exoplanet Archive which currently lists the tally at 919. Why the discrepancy? One reason, according to New Scientist, is that the Extrasolar Planets Encyclopaedia lists exoplanets as soon as their confirmation is announced at conferences. The NASA list, however, only lists them once they’ve been published in a scientific journal. The NASA list will therefore always lag its European counterpart.

Also, some of the 1,000 exoplanets in the list are subject to intense scrutiny as there are some very massive worlds with stellar characteristics. After further study, some may be characterized as brown dwarfs, or “failed stars,” bumping them from being true planetary bodies.

1,000 exoplanets may seem like a big number, but the now defunct NASA Kepler Space Telescope suggests that there are thousands of candidate exoplanetary signals in its transit data awaiting confirmation by other surveys. But even if we end up confirming thousands more over the coming years, that number will pale into insignificance considering there are an estimated 100 billion alien worlds orbiting other stars in our galaxy. Our quest to find habitable exoplanets has only just begun.

Read more at Discovery News

Oct 21, 2013

West African Bats No Safe Haven for Malaria Parasites

In Europe, bats are normally discussed in the context of endangered species threatened by loss of their habitats. However, in recent years, bats have caught the eye of infection biologists. The animals are namely hosts to a surprising number of pathogens, many of which could be dangerous to humans. Scientists at the Max Planck Institute for Infection Biology, the Museum für Naturkunde in Berlin and the American Museum of Natural History have been able to identify in West African bats four genera of parasites that are closely related to the malaria pathogen. One of them is the genus Plasmodium, which also includes the species that cause malaria in humans. The Plasmodium species in bats are very similar to that found in rodents and could advance the study of malaria pathogens' defence strategies against immune system responses.

Bats can transmit various diseases to human beings. Indeed, they serve as reservoir hosts for a long list of pathogens, including the "who's who" of dreaded killer viruses: Ebola, Marburg, Nipah, Hendra and Lyssa. The SARS outbreak in 2002 in Asia and the transmission of a previously unidentified virus (MERS) to humans in the Middle East in 2013 can both be traced back to viruses that have switched hosts from bats to humans. Bats have an exceptional immune system that can hold all these viruses in check. However, some infections in humans often have a deadly outcome.

Recently, the researchers have also found an astonishing variety of blood parasites in West African bats. They examined 31 bat species from the West African forest in Guinea, Liberia and the Ivory Coast with regard to parasites that attack red blood cells. 40 per cent of the approximately 270 examined animals carried parasites of the genera Plasmodium, Polychromophilus, Nycteria and Hepatocystis. According to the study, at least two species of Plasmodium can be found in bats. These bat pathogens are very similar to those found in rodents. "There are different arboreal rodents in the tropics that live in close vicinity to bats and in result might attract the same mosquitoes that transmit parasites from one group of animals to another," says Juliane Schaer from the Max Planck Institute in Berlin.

Plasmodium parasites cause malaria, the most important vector-borne infectious disease on the planet. These protozoan parasites reproduce in different host cells and undergo a complex life cycle in two alternating hosts. Their sexual reproduction takes place in insects; usually Anopheles mosquitoes. Following a mosquito bite, they reproduce asexually in different vertebrates. By comparing DNA, the scientists were able to establish a phlyogenetic tree for haemosporidians in bats. This showed that bats were the first mammal hosts to the pathogens. "In a later evolutionary stage, they switched to rodents and primates," Susan Perkins from the American Museum of Natural History in New York says.

It is not yet clear why bats are hosts to such a multitude of microorganisms. "One reason is probably that, in evolutionary terms, this is a very old group of animals, which moreover comprises a large number of different species. The bats' ability to fly and their tendency to form big colonies are other factors that help the parasites spread," explains Schaer.

As a consequence of the pathogen threat, bats have developed a sophisticated immune system. This might explain the finding that certain bat species show infection rates of over 60 per cent by haemosporidians and still manage to keep the parasites at bay without becoming ill. "Also, the fast asexual reproduction of the genera Polychromophilus, Nycteria and Hepatocystis in bats takes place in hepatocytes, and not in erythrocytes as in humans. Such a liver stage cannot be clinically detected in humans. "It may be that the effective immune system ousted the pathogens from the blood cells, so that they were limited to multiply in the liver," says Kai Matuschewski, Leader of the Parasitology Research Group at the Max Planck Institute for Infection Biology.

Read more at Science Daily

Grab-and-Go Beetle Hoards Poo and Gallops

Given the choice between flying and hoarding dried feces, most of us would take to the air, but a certain beetle in Africa prefers to spend its time on the ground collecting poop.

The dung beetle, which lives in the Western Cape, now gallops across the sand — like an insect Lone Ranger — while grasping coveted bits of dried feces.

“This species of Pachysoma grabs bits of poo and gallops forward with it,” Marcus Byrne of the University of Witwatersrand, was quoted as saying in a press release. “That is really odd. Most insects walk with a tripod gait. They plant three legs in a triangle, while swinging the other three legs forward. It’s an incredibly stable way of walking because you’ve always got three legs on the ground.”

“For an insect to abandon the tripod gait and use its legs together in pairs like a galloping horse is really radical. The big question is: why are they doing it?” asked Byrne, who along with his colleagues, studied the unusual insect.

Most dung beetles gather “fresh” poop and pack it into one wet ball that they roll along the ground before their big escape. Pachysoma, on the other hand, collects bits of dry dung and hoards it in a nest. The beetle goes on repeated foraging trips instead of one major journey.

Byrne and his colleagues from Lund University in Sweden think the species might have changed its mode of navigation because it needs to be able to find its way back and forth from its nest.

“For most dung beetles, it’s always a one way trip — grab the poo, run away and never go back,” he explained. “The very marked pacing of Pachysoma’s gallop might be giving it a better signal in terms of estimating the return distance from the food to its nest. When it gallops, it slips less in the soft sand.”

Prior research has found that ants count their steps as a way to navigate back and forth from home, and bees use the optical flow of scenery across their retinas to measure how far they’ve travelled to forage from the hive. Pachysoma dung beetles seem to be using a version of both techniques.

“Bees use optic flow as a measure of how fast and how far they’ve flown,” Byrne said. “Dung beetles have two eyes on each side of their head, one on top and one on the bottom, looking at the sand and we think Pachysoma might be registering optic flow with its bottom eye over the sand.”

But Pachysoma has not only changed the way it moves across land, it has also lost its ability to fly.

“There are 800 species of dung beetle in South Africa and most of them fly,” Byrne said. “To fly makes sense because poo is a very ephemeral resource. It’s only useful for a few days and it’s very patchy — you don’t know where you’re going to find the next dropping. That’s why Pachysoma is so weird. Why would anyone give up flying?”

Read more at Discovery News

Oops! Etruscan Warrior Prince Really a Princess

Last month, archaeologists announced a stunning find: a completely sealed tomb cut into the rock in Tuscany, Italy.

The untouched tomb held what looked like the body of an Etruscan prince holding a spear, along with the ashes of his wife. Several news outlets reported on the discovery of the 2,600-year-old warrior prince.

But the grave held one more surprise.

A bone analysis has revealed the warrior prince was actually a princess, as Judith Weingarten, an alumna of the British School at Athens noted on her blog, Zenobia: Empress of the East.

Etruscan tomb

Historians know relatively little about the Etruscan culture that flourished in what is now Italy until its absorption into the Roman civilization around 400 B.C. Unlike their better-known counterparts, the ancient Greeks and the Romans, the Etruscans left no historical documents, so their graves provide a unique insight into their culture.

The new tomb, unsealed by archaeologists in Tuscany, was found in the Etruscan necropolis of Tarquinia, a UNESCO World Heritage site where more than 6,000 graves have been cut into the rock.

"The underground chamber dates back to the beginning of the sixth century B.C. Inside, there are two funerary beds carved into the rock," Alessandro Mandolesi, the University of Turin archaeologist who excavated the site, wrote in an email.

When the team removed the sealed slab blocking the tomb, they saw two large platforms. On one platform lay a skeleton bearing a lance. On another lay a partially incinerated skeleton. The team also found several pieces of jewelry and a bronze-plated box, which may have belonged to a woman, according to the researchers.

"On the inner wall, still hanging from a nail, was an aryballos [a type of flask] oil-painted in the Greek-Corinthian style," Mandolesi said.

Initially, the lance suggested the skeleton on the biggest platform was a male warrior, possibly an Etruscan prince. The jewelry likely belonged to the second body, the warrior prince’s wife.

But bone analysis revealed the prince holding the lance was actually a 35- to 40-year-old woman, whereas the second skeleton belonged to a man.

Given that, what do archaeologists make of the spear?

"The spear, most likely, was placed as a symbol of union between the two deceased," Mandolesi told Viterbo News 24 on Sept. 26.

Weingarten doesn't believe the symbol of unity explanation. Instead, she thinks the spear shows the woman's high status.

Their explanation is "highly unlikely," Weingarten told LiveScience. "She was buried with it next to her, not him."

Gendered assumptions

The mix-up highlights just how easily both modern and old biases can color the interpretation of ancient graves.

In this instance, the lifestyles of the ancient Greeks and Romans may have skewed the view of the tomb. Whereas Greek women were cloistered away, Etruscan women, according to Greek historian Theopompus, were more carefree, working out, lounging nude, drinking freely, consorting with many men and raising children who did not know their fathers' identities.

Instead of using objects found in a grave to interpret the sites, archaeologists should first rely on bone analysis or other sophisticated techniques before rushing to conclusions, Weingarten said.

Read more at Discovery News

Life After Death? New Methods Halt Dying Process

The line between life and death is not as clear as once thought, now that developments in the science of resuscitation have made it possible to revive people even hours after their heart has stopped beating and they are declared dead, medical experts say.

"Historically, when a person's heart stopped and they stopped breathing, for all intents and purposes, they were dead," said Dr. Sam Parnia, an assistant professor of critical care medicine at State University of New York at Stony Brook. "There was nothing you could do to change that," Parnia told an audience at the New York Academy of Sciences last week.

However, in the process of unraveling mysteries of death at the cellular level, scientists have learned that death does not occur in a single moment, but instead is a process. It is actually after a person has died -- by our current definition of death -- that the cells of the body start their own process of dying.

This process "could take hours of time, and we could potentially reverse that," Parnia said.

It was once thought that after the heart stops pumping blood throughout the body, a person has only few minutes before suffering permanent brain damage caused by lack of oxygen and nutrients getting to the brain cells. This notion, scientists now say, is outdated.

When the heart stops beating, the process of death is only beginning, said Dr. Stephan Mayer, a professor of neurology at Columbia University and a panelist at the discussion.

Brain damage from lack of oxygen to the brain comes in stages. Within seconds, brain activity is affected, but it isn't until several minutes later that sugar-deprived cells start going through the steps of programmed cell death.

"When somebody's been without oxygen, we know there’s a whole bunch of signals that are now starting to tell cells that it's time to die. So we have an opportunity to modify that programing just a little bit, to say 'wait put the brakes on,'" said panelist Dr. Lance Becker, a professor of emergency medicine at the University of Pennsylvania.

Some insights for how to halt the dying process come from case reports of people who were brought back to life with little or no brain damage after hours of a silenced brain and heart.

The key to these successful cases, in addition to good critical care, is hypothermia, experts say. Hypothermia is a state in which the body's core temperature is brought a few degrees lower than its normal temperature of 98.6 degrees Fahrenheit (37 degrees Celsius).

Studies have found that hypothermia seems to protect the brain by decreasing its need for oxygen and aborting activated cell death pathways. Still, there are limits -- although body-cooling techniques have improved recovery in many patients after cardiac arrest, there will be a moment when the damage is too much and it's too late to come back, the experts said.

Moreover, scientists have learned that successful recovery depends on how the patient is treated after the heart is restarted and how the body is warmed after hypothermia.

"What we are learning is counterintuitive, because what we were all taught, if somebody's oxygen is low, I should give them oxygen, if their blood pressure is down, I should crank their blood pressure up," Becker said.

In reality, however, if a patient responds to initial care and his heart is restarted, a sudden rush of blood and too much oxygen to the brain could actually worsen the neurological damage. Instead, moderating the amount of oxygen delivered to the brain may be crucial in resuscitation.

The idea of cooling the body after cardiac arrest has been around for a few decades, but scientists were not certain if it truly was beneficial to patients.

In recent years, however, studies have provided evidence that hypothermia improves patient's survival and recovery, and professional societies such as the American Heart Association recommend considering hypothermia after patient's blood circulation is restored.

Nevertheless, not all hospitals have implemented hypothermia as part of their critical care protocol.

"What is sad is that this knowledge out there, the system is available but is not implemented," Parnia said. Less than 10 percent of people in the United States who might benefit from cooling therapy actually receive it, he said.

In an ideal world, resuscitation protocols would use machines instead of people to deliver chest compressions as long as needed, and to ensure right amounts of oxygen and blood are getting to the brain, Parnia said. Cooling and reducing oxygen after the heart is restarted are among factors that should increase people chances of coming back without brain damage, he said.

Read more at Discovery News

Oct 20, 2013

'Random' Cell Movement Is Directed from Within

Cell biologists at The Johns Hopkins University have teased apart two integral components of the machinery that causes cells to move. Their discovery shows that cellular projections, which act as hands to help a cell "crawl," are apparently always initiated by a network of message-relaying proteins inside the cell. It was already known that in directional movement, the network is activated by sensor proteins on the cell's surface in response to external cues. They now know that in random movement, the messenger network is also causative: It can self-activate spontaneously.

Because cellular movement is necessary for everything from embryo development to wound healing to cancer metastasis, the work is expected to have wide-ranging implications for understanding and manipulating these biological processes, the researchers say. In fact, they note that defects in the messenger protein network have been linked to many types of cancer. The findings are summarized in a paper published online Oct. 20 in the journal Nature Cell Biology.

"It was previously thought that messenger proteins were only involved in directional movement: that without them, cells could only move randomly, through the spontaneous formation of these hand-like projections," says Peter Devreotes, Ph.D., professor and director of the Department of Cell Biology at the Johns Hopkins University School of Medicine. "Now we know that even random movement requires the activation of the messenger protein network."

According to Devreotes, a key component of a cell's machinery is a crisscrossing network of protein chains that wrap around the inside edge of the cell, giving it shape and structure and inspiring the name "cytoskeleton." To allow movement, this network must build itself up in a given area of the cell, pushing the cell's membrane outward and creating a hand-like projection that can "grip" the external environment and pull the cell forward.

The cytoskeleton, Devreotes says, takes orders from the messenger protein network, which is connected to sensor proteins on the outside of the cell. The sensors detect directional signals coming from other parts of the body and pass them on to the messenger proteins, which in turn call on the cytoskeletal proteins to create a projection in the right direction.

In their experiments, the Devreotes team sought to understand the relationship between each of these components. They began, he says, by bathing their cells in a drug that paralyzes the cytoskeleton. Not surprisingly, the cells wouldn't move, but the spontaneous responses of the messenger network still occurred.

Devreotes explains, "You can think of the cell as a row boat with several crewmen and a coxswain, sitting in the rear, steering the rudder and shouting at the crew to keep their movements in sync. If the oars are taken away (i.e., a paralyzed cytoskeleton), the coxswain can yell at the crew as much as he wants but the boat won't move."

Using a combination of genetic and imaging techniques, the team then incapacitated the other components of the system one by one and watched what happened. Inhibiting the messenger proteins (the coxswain) showed that the cytoskeleton has an intrinsic rhythm that "ruffles" the cell membrane every 10 seconds, but there were no projections created, so the cells didn't move. "It's as if the crew can still row without the coxswain but each person is rowing in a different direction so the boat just stays where it is," says Chuan-Hsiang Huang, a co-author of the study.

The team expected that when they removed the sensor proteins they would see no movement, based on the old idea that both random and directional cell movement required signaling from these proteins. However, they found instead that the messenger network is "excitable." That is, without the sensor proteins or external cues, the messenger proteins can still work on their own, telling the cytoskeleton to create projections here or there, moving the cells about randomly. "This situation could be compared to a boat without a rudder. The coxswain is there to coordinate the rowing of the crew so the boat does move, but not in any specific direction," explained co-author Ming Tang.

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Mixing Nanoparticles to Make Multifunctional Materials

Scientists at the U.S. Department of Energy's Brookhaven National Laboratory have developed a general approach for combining different types of nanoparticles to produce large-scale composite materials. The technique, described in a paper published online by Nature Nanotechnology on October 20, 2013, opens many opportunities for mixing and matching particles with different magnetic, optical, or chemical properties to form new, multifunctional materials or materials with enhanced performance for a wide range of potential applications.

The approach takes advantage of the attractive pairing of complementary strands of synthetic DNA-based on the molecule that carries the genetic code in its sequence of matched bases known by the letters A, T, G, and C. After coating the nanoparticles with a chemically standardized "construction platform" and adding extender molecules to which DNA can easily bind, the scientists attach complementary lab-designed DNA strands to the two different kinds of nanoparticles they want to link up. The natural pairing of the matching strands then "self-assembles" the particles into a three-dimensional array consisting of billions of particles. Varying the length of the DNA linkers, their surface density on particles, and other factors gives scientists the ability to control and optimize different types of newly formed materials and their properties.

"Our study demonstrates that DNA-driven assembly methods enable the by-design creation of large-scale 'superlattice' nanocomposites from a broad range of nanocomponents now available-including magnetic, catalytic, and fluorescent nanoparticles," said Brookhaven physicist Oleg Gang, who led the research at the Lab's Center for Functional Nanomaterials (CFN). "This advance builds on our previous work with simpler systems, where we demonstrated that pairing nanoparticles with different functions can affect the individual particles' performance, and it offers routes for the fabrication of new materials with combined, enhanced, or even brand new functions."

Future applications could include quantum dots whose glowing fluorescence can be controlled by an external magnetic field for new kinds of switches or sensors; gold nanoparticles that synergistically enhance the brightness of quantum dots' fluorescent glow; or catalytic nanomaterials that absorb the "poisons" that normally degrade their performance, Gang said.

"Modern nano-synthesis methods provide scientists with diverse types of nanoparticles from a wide range of atomic elements," said Yugang Zhang, first author of the paper. "With our approach, scientists can explore pairings of these particles in a rational way."

Pairing up dissimilar particles presents many challenges the scientists investigated in the work leading to this paper. To understand the fundamental aspects of various newly formed materials they used a wide range of techniques, including x-ray scattering studies at Brookhaven's National Synchrotron Light Source (NSLS) and spectroscopy and electron microcopy at the CFN.

For example, the scientists explored the effect of particle shape. "In principle, differently shaped particles don't want to coexist in one lattice," said Gang. "They either tend to separate into different phases like oil and water refusing to mix or form disordered structures." The scientists discovered that DNA not only helps the particles mix, but it can also improve order for such systems when a thicker DNA shell around the particles is used.

They also investigated how the DNA-pairing mechanism and other intrinsic physical forces, such as magnetic attraction among particles, might compete during the assembly process. For example, magnetic particles tend to clump to form aggregates that can hinder the binding of DNA from another type of particle. "We show that shorter DNA strands are more effective at competing against magnetic attraction," Gang said.

For the particular composite of gold and magnetic nanoparticles they created, the scientists discovered that applying an external magnetic field could "switch" the material's phase and affect the ordering of the particles. "This was just a demonstration that it can be done, but it could have an application-perhaps magnetic switches, or materials that might be able to change shape on demand," said Zhang.

The third fundamental factor the scientists explored was how the particles were ordered in the superlattice arrays: Does one type of particle always occupy the same position relative to the other type-like boys and girls sitting in alternating seats in a movie theater-or are they interspersed more randomly? "This is what we call a compositional order, which is important for example for quantum dots because their optical properties-e.g., their ability to glow-depend on how many gold nanoparticles are in the surrounding environment," said Gang. "If you have compositional disorder, the optical properties would be different." In the experiments, increasing the thickness of the soft DNA shells around the particles increased compositional disorder.

These fundamental principles give scientists a framework for designing new materials. The specific conditions required for a particular application will be dependent on the particles being used, Zhang emphasized, but the general assembly approach would be the same.

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