Sep 14, 2013

Spider Silk Coated With Carbon Nanotubes Has Multiple Surprising Uses

Eden Steven, a physicist at Florida State University's MagLab facility, discovered that simple methods can result in surprising and environmentally friendly high-tech outcomes during his experiments with spider silk and carbon nanotubes, the results of which are now published in the online research journal Nature Communications.

"If we understand basic science and how nature works, all we need to do is find a way to harness it," Steven said. "If we can find a smart way to harness it, then we can use it to create a new, cleaner technology."

Steven is the lead investigator on the paper "Carbon nanotubes on a spider silk scaffold." The experiment may result in practical applications in electrical conductivity and more.

Think of a nanotube as a one-atom thick sheet of carbon that's been rolled into an infinitesimally tiny tube. A nanotube's diameter is at least 10,000 times smaller than a strand of human hair. Physicists know that when things get that microscopically minute, they act very strange. Researchers worldwide are intrigued by the properties of carbon nanotubes, including their amazing strength and ability to conduct electricity and heat.

Steven wanted to see what would happen when strands of spider silk were coated with carbon nanotubes. Keeping with his theme of simplicity, he gathered the spider silk himself, hiking around the MagLab and using a stick to gather webs. To adhere the powdery carbon nanotubes to the spider silk, he ultimately discovered that just a drop of water worked best.

"It turns out that this high-grade, remarkable material has many functions," Steven said of the silk coated in carbon nanotubes. "It can be used as a humidity sensor, a strain sensor, an actuator (a device that acts as an artificial muscle, for lifting weights and more) and as an electrical wire."

Rather than add to the already immense amount of toxic elements and complex, non-biodegradable plastics found in today's electronic devices and as pollution in our environment, Steven wanted to investigate eco-friendly materials. He was especially interested in materials that could deal with humidity without complicated treatments and chemical additives. Spider silk fit the bill.

"Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications," Steven wrote in the Nature Communications paper. "Spider silk is tough, but becomes soft when exposed to water. … The nanotubes adhere uniformly and bond to the silk fiber surface to produce tough, custom-shaped, flexible and electrically conducting fibers after drying and contraction."

Steven collaborated with six other scientists on the research project, including Florida State University Physics Department Chair James Brooks and Fulbright scholar and Iraqi physicist Wasan Saleh. Saleh worked with Steven and Brooks at the MagLab in 2011 as one of 10 Iraqi Fulbright scholars, and the only woman in the Iraqi group, to visit Florida State that summer.

In addition to Saleh, with the University of Baghdad, the other researchers who collaborated on the paper were: Steve F.A. Acquah, with the FSU Department of Chemistry and Biochemistry; Rufina G. Alamo, with the FAMU-FSU Department of Chemical and Biomedical Engineering; Victor Lebedev, with the Institute of Materials Science of Barcelona; and Vladimir Laukhin, with the Catalan Institution for Research and Advanced Studies in Barcelona.

Read more at Science Daily

Tuna Closely Related to Some of the Strangest Fish in the Sea

Some of the strangest fish in the sea are closely related to dinner table favourites the tunas and mackerels, an international team including Oxford University scientists has found.

Deep sea fish such as the black swallower, with an extendable stomach that enables it to eat fish larger than itself, and manefishes, some sporting spiky fins like a Mohican haircut, are close cousins to mackerels and tuna despite having completely different body shapes and lifestyles.

The team, led by Dr Masaki Miya at Chiba Natural History Museum in Japan, suggests that this extended family of fishes might owe its success today to the devastating extinction that marked the demise of dinosaurs and many other creatures 66 million years ago.

The researchers report in the journal PLOS ONE this week how they combined DNA analysis of over 5,000 modern fish species with fossil evidence to solve the mystery of which species were closest to tunas and mackerels in the fish family tree.

'What was immediately clear from our result is that the extended family of tunas and mackerels is made up of fishes that all look very different from one another, with different ways of life, but which share one key trait: they all dwell in the open ocean,' said Dr Miya of Chiba Natural History Museum. 'This had been suggested before, but we were able to show that many additional groups of fishes inhabiting the open ocean -- called the pelagic realm -- were closely related to one another and to tunas.'

Reflecting this preference for the open ocean the team has called the extended tuna family tree: 'Pelagia'. Although they share a preference for open-ocean habitats, members of Pelagia show radically different ways of life ranging from deep-sea fishes that live inside sac-like invertebrates to speedy, shallow-water predators such as the tuna.

'Discovering that such radically different fish species are related is a bit like finding that a seal is more closely related to a cat than it is to a walrus!' said Dr Matt Friedman of Oxford University's Department of Earth Sciences, a co-author of the PLOS ONE paper. 'By comparing genetic data with fossil evidence we were able to show that the origins of all these disparate groups lie in a period of rapid evolution that occurred around 65 million years ago. This is significant because this is when the Cretaceous extinction event that wiped out the dinosaurs also killed off many groups of large fishes inhabiting the open ocean.

'It's likely that the common ancestor of this family lived in the deep ocean, helping it to survive this ancient extinction. It then emerged from its refuge to diversify and colonise the shallower waters to produce the profusion of related, but very different, species we see today.'

According to the team the new findings suggest a different way of thinking about past extinctions.

Read more at Science Daily

Sep 13, 2013

Pinpointing When the First Dynasty of Kings Ruled Egypt

For the first time, a team of scientists and archaeologists has been able to set a robust timeline for the first eight dynastic rulers of Egypt. Until now there have been no verifiable chronological records for this period or the process leading up to the formation of the Egyptian state. The chronology of Early Egypt between 4500 and 2800 BC has been reset by building mathematical models that combine new radiocarbon dates with established archaeological evidence. Over 100 fresh radiocarbon dates were obtained for hair, bone and plant samples excavated at several key sites including the tombs of the kings and surrounding burials.

The findings are published in the journal Proceedings of the Royal Society A.

Egypt was the first territorial state to be brought under one political ruler, and the new dating evidence suggests that this period of unification happened far more quickly than previously thought.

Until now scholars had relied on archaeological evidence alone, using the evolving styles of ceramics excavated at human burial sites to try to piece together the timings of key chronological events in the Predynastic period and the First Dynasty. For example, among the most significant pieces of evidence surviving today are two mud seals, excavated at the royal tombs at Abydos, containing lists in successive order of the First Dynasty kings.

Using the fresh radiocarbon dates combined with existing archaeological evidence, the research team's mathematical model pinpointed the likeliest date for each king's accession. The date for each king is thought to be accurate to within 32 years (with 68% probability). The modelled timeline reveals lengths of reign that are approximately what you would expect in terms of lifespan, say the study authors.

The Egyptian state is often defined as starting when King Aha acceded to the throne. According to the new model, this is likely to have happened between 3111 BC and 3045 BC (with 68% probability). It also shows that the Predynastic period -- when inhabitants along the River Nile started to form permanent settlements and concentrate on crop farming -- was shorter than previously thought. It had been widely assumed that the Predynastic period started around 4000 BC. However, this model suggests it was probably closer to 3800-3700 BC, and the Neolithic period that preceded it lasted longer and finished later.

Lead author of the study Dr Michael Dee, from the Research Laboratory for Archaeology at the University of Oxford, said: 'The origins of Egypt began a millennium before the pyramids were built, which is why our understanding of how and why this powerful state developed is based solely on archaeological evidence. This new study provides new radiocarbon dating evidence that resets the chronology of the first dynastic rulers of Ancient Egypt and suggests that Egypt formed far more rapidly than was previously thought.'

The first kings and queens of Egypt in order of succession were Aha, Djer, Djet, Queen Merneith, Den, Anedjib, Semerkhet and Qa'a. They would have ruled over a territory spanning a similar area to Egypt today with formal borders at Aswan in the south, the Mediterranean Sea in the north and across to the modern-day Gaza Strip in the east.

Read more at Science Daily

Dating of Beads Sets New Timeline for Early Humans

An international team of researchers led by Oxford University have new dating evidence indicating when the earliest fully modern humans arrived in the Near East, the region known as the Middle East today. They have obtained the radiocarbon dates of marine shell beads found at Ksar Akil, a key archaeological site in Lebanon, which allowed them to calculate that the oldest human fossil from the same sequence of archaeological layers is 42,400-41,700 years old. This is significant because the age of the earliest fossils, directly and indirectly dated, of modern humans found in Europe is roughly similar. This latest discovery throws up intriguing new possibilities about the routes taken by the earliest modern humans out of Africa, says the study published online by the journal PLOS ONE.

The research team radiocarbon dated 20 marine shells from the top 15 metres of archaeological layers at Ksar Akil, north of Beirut. The shells were perforated, which indicates they were used as beads for body or clothes decoration by modern humans. Neanderthals, who were living in the same region before them, were not making such beads. The study confirms that the shell beads are only linked to the parts of the sequence assigned to modern humans and shows that through direct radiocarbon dating they are between 41,000-35,000 years old.

The Middle East has always been regarded as a key region in prehistory for scholars speculating on the routes taken by early humans out of Africa because it lies at the crossroads of three continents -- Africa, Asia and Europe. It was widely believed that at some point after 45,000 years ago early modern humans arrived in Europe, taking routes out of Africa through the Near East, and, from there, along the Mediterranean rim or along the River Danube. However, this dating evidence suggests populations of early modern humans arrived in Europe and the Near East at roughly the same time, sparking a new debate about where the first populations of early humans travelled from in their expansion towards Europe and which alternative routes they may have taken.

In Ksar Akil, the Lebanese rockshelter, several human remains were found in the original excavations made 75 years ago. Unfortunately since then, the most complete skeleton of a young girl, thought to be about 7-9 years of age buried at the back of the rock shelter, has been lost. Lost also are the fragments of a second individual, found next to the buried girl. However, the team was able to calculate the age of the lost fossil at 40,800-39,200 years ago, taking into account its location in the sequence of archaeological layers in relation to the marine shell beads.

Another fossil of a recently rediscovered fragment of the upper jaw of a woman, now located in a museum in Beirut, had insufficient collagen to be dated by radiocarbon methods. A method using statistical modelling was used to date by association the jaw fragment at 42,400-41,700 years old.

Ksar Akil is one of the most important Palaeolithic sites in Eurasia. It consists of a 23 metre deep sequence of archaeological layers that lay undisturbed for thousands of years until a team of American Jesuit priests excavated the rockshelter in 1937-38, and again after the end of the WWII, in 1947-48. The cave layers were found to contain the human fossils and hundreds of shell beads, as well as thousands of stone tools and broken bones of hunted and consumed animals.

Study lead author Dr Katerina Douka, from the School of Archaeology at the University of Oxford, said: 'This is a region where scholars have been expecting to find early evidence of anatomically and behaviourally modern humans, like us, leaving Africa and directly replacing Eurasian Neanderthal populations that lived there for more than 150,000 years. The human fossils at Ksar Akil appear to be of a similar age to fossils in other European contexts. It is possible that instead of the Near East being the single point of origin for modern humans heading for Europe, they may also have used other routes too. A maritime route across Mediterranean has been proposed although evidence is scarce. A wealth of archaeological data now pinpoints the plains of Central Asia as a particularly important but relatively unknown region which requires further investigation.'

The earliest European modern fossil, from Romania, dates to between 42,000-38,000 years before the present time, and specialists have estimated the age of Kent's Cavern maxilla from southern England, between 44,000-41,000 years, and that of two milk teeth in southern Italy, at 45,000-43,000 years old. The new dating evidence from Ksar Akil is largely comparable to these ages, if not slightly younger.

Read more at Science Daily

Evolution’s Clock Ticked Faster at the Dawn of Modern Animals

Five hundred thirty million years ago, the number and diversity of life forms on Earth mushroomed. This so-called Cambrian explosion kept Charles Darwin, the father of evolution, awake at night, as he worried that his theory of natural selection couldn’t explain the sudden proliferation of species. Now, researchers have combined evidence from the fossil record with clues in the genes of living species to estimate the speed of that evolutionary explosion. Their finding—that the rate of change was high, but still plausible—may put Darwin’s fears to rest.

The dawn of the Cambrian period divides two very different Earths. In one, primitive, mostly single-celled creatures “sat on the mud and did very little,” says evolutionary biologist Matthew Wills of the University of Bath in the United Kingdom. In the other, life forms as diverse as our modern fauna roamed the planet. The abrupt appearance of these creatures in the fossil record “gave Darwin a headache,” Wills says, and critics of evolution have argued that the tree of life couldn’t possibly produce so many branches and bear such a variety of fruit so quickly.

Some scientists explained away this dilemma by claiming that the fossil record is deceptive. Perhaps, they speculated, the first representatives of modern animal groups appeared long before the Cambrian period, but had tiny, soft bodies what were not easily preserved as fossils. But based on fossil evidence, most paleontologists believe the “fuse” on the explosion must have been short, with new life forms proliferating only a few tens of millions of years before the Cambrian period. Just how quickly would species have to evolve to squeeze in all these new developments?  “No one has actually tried to quantify just how fast the rates were,” says Michael Lee, an evolutionary biologist at the University of Adelaide in  Australia and the South Australian Museum, who led the new research. “They just literally took Darwin’s word that they must have been pretty fast.”

So Lee and colleagues estimated that speed by studying the evolution of arthropods—Earth’s most diverse phylum, which includes insects, crustaceans, and arachnids. They looked at how changes evolved in both the genetic code and the anatomy of arthropods, comparing 62 different genes and 395 physical traits. For any two branches of the arthropod family tree—centipedes and millipedes, for example—they picked out important physical differences and variations in genetic sequence in modern specimens. Then, using evidence from the fossil record about how quickly the two branches diverged, the group calculated roughly how fast genetic and anatomical differences must have emerged for each lineage over time.

They found that when some early branches of the arthropod family tree were splitting off, creatures were evolving new traits about four times faster than they did in the following 500 million years. The creatures’ genetic codes were changing by about .117 percent every million years—approximately 5.5 times faster than modern estimates, the group reports online today in Current Biology. Lee calls this pace “fast, but not too fast” to reconcile with Darwin’s theory.

This combined model for genes and anatomy represents “quite a stride forward,” Wills says. The results not only show that the evolutionary clock ticked much faster around the time of the Cambrian, but also hint at what may have sped it up. The fact that genes and anatomy evolved at roughly the same rate suggest that pressures to adapt and survive in a world of new, complex predators drove both, the authors speculate. Innovations such as exoskeletons, vision, and jaws created new niches and evolution sped up to fill them. Wills agrees that the new research makes this explanation for the Cambrian explosion “look a lot more probable now.”

Others caution that such analysis is in its infancy. “It’s an excellent first step,” says Douglas Erwin, a paleontologist at the Smithsonian Institution in Washington, D.C., but the exact rates of evolution in the study might not be reliable. He points out that while the study uses fossil data to determine when a given arthropod branch emerged, it doesn’t include the known characteristics of these extinct ancestors in its comparisons of physical traits, which involve only living creatures.

Read more at Wired Science

Ig Nobel Prizes: A Duck-Gnawed Penis, Dung Beetles

Amid a flurry of paper airplanes, hosts adorned with little more than silver body paint, and the world's first and only opera about a centrifugal-force birthing machine, the 2013 Ig Nobel Prizes were awarded tonight (Sept. 12).

The Ig Nobels, which are awarded each year in the historic Sanders Theater on the Harvard University campus, honor scientific research that makes people laugh, then makes them think -- and then makes them laugh again. The science is real, and though it's been published in prestigious, peer-reviewed academic journals, it all has considerable popular appeal.

Who hasn't wondered, for example, about the effect that opera music might have on mice after they've had a heart transplant? (It helps, apparently.) And who among us, when seeing an amputated penis -- after it's been partially gnawed on by a duck -- hasn't asked, "Hey, is there a surgical technique that can help here?" (Answer: No, there isn't.)

The Joint Prize in Biology and Astronomy Prize went to a team for their celestial discovery that lost dung beetles find their way home by looking at the Milky Way, that is, after they do a little jig on their perfectly rolled balls of poo. Physicists snagged an Ig Nobel for figuring out that walking on water is possible, if the water walker and the water are located on the moon.

Finally, these and other scientific inquiries are getting the recognition they've long deserved. And while some recipients are in on the spoof on the Nobel Prizes and enjoy the laughs as much as the spirited audience, others are apparently nonplussed by the honor bestowed by the Ig Nobels.

Notably absent, for example, was the winner of this year's Ig Nobel Peace Prize, Belarus President Alexander Lukashenko, who declared it illegal to applaud in public. He shares the prize with the Belarus State Police, who arrested a one-armed man for clapping. But neither of these visionaries sent representatives to the unceremonious ceremony.

Another no-show was the winner in the Safety Engineering category, Gustano Pizzo, who invented an electro-mechanical system to drop would-be airplane hijackers through a trap door, seal them in a package, and then parachute that package — hijacker and all — into the arms of the police. Sadly, Pizzo died in 2006 before he could receive his Ig Nobel Prize, which comes with a $10 trillion bill (a $10 trillion Zimbabwean dollar bill, that is).

And though there's no category for research that could be greeted with a resounding "duh," the winners of this year's Ig Nobel Psychology Prize were a group of international scientists who confirmed that people who think they are drunk also think they are attractive. Their gobsmacking research was published in the prestigious British Journal of Psychology.

Among the highlights of this year's ceremony was the premiere of an original opera in four acts, "The Blonsky Device," which celebrates the work of George and Charlotte Blonsky. The couple was granted a U.S. patent in 1965 for a machine that would facilitate the birth of a child by centrifugal force. (The theme of this year's award ceremony was Force.)

The Blonskys' innovation featured a large circular table onto which a pregnant woman was strapped. Like a giant record player, the table — and its passengers — rotated at high speeds. For their invention (which was apparently never built, let alone used), the Blonskys were awarded an Ig Nobel in 1999.

The Ig Nobel award ceremony is, according to the playbill, "reluctantly inflicted upon you by the international science humor magazine Annals of Improbable Research (AIR)."

Read more at Discovery News

Sep 12, 2013

Interlocking Gears Found on Common Insect

Embedded in the back legs of a common jumping insect are rotating gear wheels that allow the tiny creatures to leap with astounding speed.

It is the first time that anything resembling gears have been found in a living creature, and the discovery goes to show that nature often tends to beat us at our own engineering game. In this case, evolution produced gears long before people figured out how to build them.

“We always think of gears as a human invention -- we are familiar with them on our bikes and on our cars, but we never associate them with animals,” said Malcolm Burrows, a neurobiologist and biomechanist at the University of Cambridge in the United Kingdom. “It’s a very simple and neat solution to what would otherwise be an incredibly difficult problem.”

Common in both North America and Europe, the planthopping insect called Issus can’t fly but it is able to launch itself with impressive power and speed by pushing off with its two hind legs. As adults, Burrows said, the insects accelerate faster than a Ferrari.

Unlike grasshoppers, whose legs are located on the sides of its trunk, Issus’ legs lie beneath its body. That creates a problem. Whereas a grasshopper can push off with one leg and still hop straight, a planthopper that tried jumping with just one leg would spin rapidly around the axis of its body.

Instead, the insect’s two rear legs move with remarkable coordination.

To better understand how, Burrows and colleague Gregory Sutton took high-speed videos that captured up to 30,000 frames each second of Issus nymphs as they jumped.

The images showed that the insect’s two hindlegs always moved within 30 microseconds of each other. A microsecond is one millionth of a second, and 30 microseconds is significantly less time than it takes for a single nerve impulse to reach the muscles in the animal’s legs.

Because their nervous systems are too slow to synchronize movement of the hind legs, the insects have developed a mechanical solution. Close-up high-speed images revealed gear wheels on each hind leg with about a dozen teeth that interlock, the researchers report today in the journal Science. These gears ensure that the force of movement transfers almost instantly from one leg to the other.

“Their gears are remarkably similar to the way we build gears,” Burrows said. “Insects obviously evolved this mechanism many millions of years ago and we only got around to it fairly recently.”

Read more at Discovery News

Humans Acquitted of Mammoth Murder

Like in a TV crime drama, DNA evidence proved crucial to solving the mystery of an ancient cold case from a very cold time. A recent genetic analysis provided evidence that seems to acquit humans of causing the woolly mammoth’s extinction. Instead, it seems the climate may have committed mammoth murder.

The DNA analysis suggested that mammoths nearly died out 120,000 years ago during a warm period, long before human hunters would have been a serious threat. The prehistoric pachyderms bounced back, only to decline again approximately 20,000 years ago.

Oddly, 20,000 years ago was actually the height of the last ice age. The authors of the study, published in the Proceedings of the Royal Society B, suggested that the environment may have become too cold and disrupted the grassland habitat the mammoths depended upon. Then, when the climate warmed again, the animals’ preferred ecosystem was taken over by tundra and forest.

The one-two climatic punch may have been the ultimate reason for the furry elephant’s demise, but humans may have helped them along. Archeological evidence, such as cave paintings and ivory carvings, suggest that humans hunted ice age elephants and used them as a source of raw materials.

However, a single mammoth would have provided tons of meat, enough to feed hundreds of humans for weeks, according to the Pennsylvania State University’s Mammoth Genome Project. Since human populations were so low at the time, it seems unlikely that scattered bands of hunters would have been enough to extinguish the ice age elephants in Europe and Asia without help from a changing climate.

In the Western Hemisphere, humans were munching on mastodons, a relative of the woolly mammoth. At the Manis mastodon site in Washington state, a butchered mastodon was found with the tip of a spear embedded in its rib. The point, made from another mastodon’s bone, would have needed to be at least 27-32 cm (10.6-12.6 in.) long to penetrate the skin and flesh of the ancient beast, according to a study in Science. The site dated to 13,800 years ago.

Read more at Discovery News

'Sorcerer' Scams Woman for Sex and Money

An Israeli man claiming to have mystical powers has been accused of tricking a client into giving him sexual favors and money while claiming to cast spells making her ex-lover return.

According to a story in the Jerusalem Post, “the woman found the 39-year-old Golan Heights resident on the Internet and asked him to help her with holistic treatment to recover from emotional despair caused by the break-up.

“Over the coming months the man held a number of meetings with the woman, during which he promised that through the power of sorcery he could make her boyfriend come back to her — all while charging her thousands of shekels in fees.”

One of the rituals allegedly required the woman to have sex with the man, which she did. Neither the woman nor the sorcerer she hired have been named, and police are looking for additional victims.

As bizarre as this situation is, it’s not unusual.

Just last year two women accused Karl Lang, a British psychic, of sexual exploitation, one saying that he tricked her into stripping naked during a séance and performing “like a porn star” in exchange for a promise that she could contact her dead grandfather. A second victim claimed that Lang convinced her that her dead father was communicating with him, encouraging her to undress and masturbate to improve her psychic powers.

She said that she felt “brainwashed, manipulated and groomed” by the alleged psychic. In June 2012 Lang was convicted of a dozen counts of causing women to engage in sexual activity without consent and sentenced to two years in jail.

Recipe for Exploitation

When those in authority claim to have unproven, special powers and give messages from the dead to vulnerable and grieving people, it’s a recipe for manipulation. Even when the exploitation isn’t sexual, it can be financial and emotional — and anyone can be a victim, even the rich and famous.

Best-selling romance author Jude Deveraux, for example, recently testified against her one-time psychic adviser Rose Marks, who she turned to when anxious and depressed over her divorce 17 years ago.

According to the Sun-Sentinel, “Marks is fighting federal charges she masterminded a conspiracy that defrauded clients to the tune of $25 million, including about $17 million from the writer. ‘She said money is energy and money is evil and if I had money in my bank account, I was attracting evil,’ Deveraux said.

During this time, Deveraux’s 8-year-old son died in an ATV motorcycle accident, and she testified that she had eight miscarriages and suffered through a messy divorce, the Sun-Sentinel reported.

Even more disturbingly, Deveraux claims that after her son’s death in 2005, Marks “tormented her with claims that the child had not gone to heaven and that Marks could transfer the child’s soul or spirit into the body of another person, reuniting mother and son. ‘She said all she saw were flames and I had to keep him out of the flames,’ Deveraux testified.”

Read more at Discovery News

Voyager: Goodbye Solar System, Hello Interstellar Space

After a 35-year, 13-billion mile journey, NASA’s Voyager 1 spacecraft left the solar system to become the first human-made object to reach interstellar space, new evidence from a team of scientists shows.

“It’s kind of like landing on the moon. It’s a milestone in history. Like all science, it’s exploration. It’s new knowledge,” long-time Voyager scientist Donald Gurnett, with the University of Iowa, told Discovery News.

In the end, it was the sun itself that in essence “rang Voyager’s bell,” providing the definitive proof that had eluded scientists for the past year or so about whether or not the spacecraft had left the solar system.

On Aug. 25, 2012, Voyager, which was launched in 1977 to study the outer planets, detected a sudden drop in the number of particles trapped in the bubble of space under the sun’s influence, the so-called heliosphere, and a corresponding spike in the number of galactic cosmic rays from outside the solar system.

That evidence alone, however, was not enough to convince scientists Voyager had finally reached interstellar space. What they really wanted to know was how much plasma -- ionized molecules and atoms -- was around Voyager, but that measurement was not possible since the spacecraft’s plasma detector stopped working more than 30 years ago.

Computer models had long predicted that within the heliosphere, which is filed with the sun’s hot breath of solar wind, plasma density would be a small fraction of what exists in cold interstellar space.

But there was another way. Under very special circumstances, Voyager’s two 10-meter (33-foot) antennas can detect vibrations in the plasma that scientists can then use to calculate density.

“If you displace the electrons from their normal position and release them, there is a restoring force that pulls them back and the electrons then oscillate. It’s a very characteristic frequency -- like hitting a bell -- and if we can detect that we can compute the density,” Gurnett said.

“It’s very straight-forward,” he added.

But not very common. It happened nine years ago when Voyager 1 crossed a shockwave, a telltale sign that the solar wind was no longer moving at supersonic speeds.

Another hint of Voyager’s whereabouts came in October and November 2012 when the spacecraft’s antennas registered the effects of a solar flare. The bevy of particles emitted in the so-called coronal mass ejection traveled for about a year before reaching Voyager.

Conclusive proof came this spring when Voyager detected another solar outburst.

“We were able, for the first time, to measure the density of the plasma, the number of particles per cubic meter,” Gurnett said. “As soon as we detected those oscillations, we knew that we were in the interstellar medium.”

“The definition of the heliopause is based on the plasma density and they just couldn’t measure that. And we, by some good fortune having to do with solar events, finally could do that,” he said.

Read more at Discovery News

Sep 11, 2013

Mayan Grave Yields Dozens of Mutilated Bodies

An excavation at the site of an ancient Maya city in Mexico has yielded a gruesome find: the remains of dismembered, decapitated bodies. The discovery provides new archaeological evidence for the violent scenes depicted in Maya art, the researchers say.

Nicolaus Seefeld, an archaeologist at the University of Bonn in Germany, stumbled across the 1,400-year-old mass grave as part of his work on the water system in the city of Uxul. The remains of 24 people were found in an approximately 344-square-foot (32 square meters) artificial cave that served as a water storage reservoir.

"Right before 24 victims were buried, the cave's interior had doubtlessly still been used a water reservoir, since the cave's floor was perfectly clean," Seefeld told LiveScience in an email. "After the 24 victims had been buried, the pre-Hispanic Maya covered the remains with a coarse layer of gravel and sealed it with a clay layer. Due to this sealing layer, the documented bones were found in an extraordinarily good state of preservation."

Skulls were scattered around the cave, with no relation to the rest of the bodies. Hatchet marks on the cervical vertebrae (or neck bones) indicated the victims were decapitated. Meanwhile, most of the lower jaws had been separated from the heads. [Photos: 'Alien' Skulls from Mexico Reveal Odd, Ancient Tradition]

Seefeld found the remains of a severed leg, feet, hands and arms with the bones still articulated, or connected at the joints. This pattern indicates "that victims were killed at the same time, then chopped into several pieces and finally buried in the artificial cave," Seefeld said in an email.

The archaeologists' analysis revealed the age and sex of 15 of the dead: Two were women; and all were between 18 and 42 at the time of death. As to their backstory, Seefeld and colleagues have formulated two possible scenarios. They suggest the dead may have been prisoners of war from another city or nobles from within Uxul.

Maya art depicts scenes of violence, including warfare, and the capture and sacrifice of captives. However, the archaeological evidence for this violence has been limited, Seefeld told LiveScience.

Supporting the idea that the dead in the Uxul mass grave had been nobles, some of the bodies had jade tooth decorations, which the researchers interpreted as a sign of high social status.

Ceramics found in the artificial cave at Uxul suggest the grave dates to the seventh century. At the time, evidence suggests,Uxul's nobility lost their titles when the city was incorporated into the Kaan Dynasty, centered at Calakmul, which was 21 miles (33 kilometers) north of Uxul, raising the possibility these victims were once nobility, Seefeld wrote.

More likely, however, the victims came from another site, he wrote. To determine which one is the case, the researchers are planning to conduct a chemical analysis on the remains.

Uxul was a midsize city located in what is now Mexico, close to the Guatemalan border. Explorers Karl Ruppert and John H. Denison discovered the remains of the city, which flourished during the Maya Classical Period from A.D. 250 to 900, and named it Uxul, a Maya word meaning "at the end."

Read more at Discovery News

Ancient Road Leading to Stonehenge Found

Scientists have uncovered a portion of an ancient path that may have led to Stonehenge.

While dismantling a modern road that runs near Stonehenge, the archaeologists uncovered two ditches found to be remnants of an ancient pathway called the avenue. Archaeologists have known of the avenue and suspected it led directly to the monument, but the modern road had cut the delicate pathway in two, obscuring its purpose. The new discovery confirms the avenue's role as an ancient pathway to the site.

"We found the bottoms, the truncated ditches, that belong to the feature known as the avenue, which is the processional leading up to Stonehenge," said archaeologist Heather Sebire, a property curator for English Heritage, which manages Stonehenge.

An exceptionally dry season also revealed the imprints where three stones used to lie in the main stone circle, suggesting the massive stone monument was once a complete circle.

Removing a road

The purpose of Stonehenge is an enduring mystery. Some have argued it was a massive sound illusion, a symbol of unity or a monument built on a sacred hunting ground.

For years, English Heritage had planned to remove the A344 road that snaked through the area and cut quite close to Stonehenge. Though archaeologists suspected the A344 had cut the avenue almost perpendicularly, they weren't optimistic they would find any traces of the earthwork, because the road is now recessed into the ground below the grass level.

But after workers pulled up the tarmac of the road, archaeologists noticed two parallel ditches that were almost perpendicular to the road. The ditches connected the truncated parts of the avenue. Though the banks of the pathway have long since disappeared, the ditches remained.

The discovery confirms that the avenue, which is about 1 foot (30 centimeters) wide, extended 0.3 miles (0.5 kilometers) straight to the stone monument before snaking onward for about 1.5 miles (2.4 km) to the Avon River in the nearby village of Amesbury.

No one knows exactly what the avenue was used for, but archaeologists have some ideas.

"We think it was a processional way; it was where people processed up into Stonehenge," Sebire told LiveScience.

Dry summer

An unusually dry summer also has revealed the presence of three dry patch marks within the stone circle where massive boulders may have once stood. Dry weather can often reveal archaeological features that have been obscured for centuries.

But those traces can be fleeting, Sebire said.

"They're quite ephemeral. It rained a few weeks ago, and it disappeared," Sebire said.

Read more at Discovery News

The Falling Man

Do you remember this photograph? In the United States, people have taken pains to banish it from the record of September 11, 2001. The story behind it, though, and the search for the man pictured in it, are our most intimate connection to the horror of that day.

In the picture, he departs from this earth like an arrow. Although he has not chosen his fate, he appears to have, in his last instants of life, embraced it. If he were not falling, he might very well be flying. He appears relaxed, hurtling through the air. He appears comfortable in the grip of unimaginable motion. He does not appear intimidated by gravity's divine suction or by what awaits him. His arms are by his side, only slightly outriggered. His left leg is bent at the knee, almost casually. His white shirt, or jacket, or frock, is billowing free of his black pants. His black high-tops are still on his feet. In all the other pictures, the people who did what he did -- who jumped -- appear to be struggling against horrific discrepancies of scale. They are made puny by the backdrop of the towers, which loom like colossi, and then by the event itself. Some of them are shirtless; their shoes fly off as they flail and fall; they look confused, as though trying to swim down the side of a mountain. The man in the picture, by contrast, is perfectly vertical, and so is in accord with the lines of the buildings behind him. He splits them, bisects them: Everything to the left of him in the picture is the North Tower; everything to the right, the South. Though oblivious to the geometric balance he has achieved, he is the essential element in the creation of a new flag, a banner composed entirely of steel bars shining in the sun. Some people who look at the picture see stoicism, willpower, a portrait of resignation; others see something else -- something discordant and therefore terrible: freedom. There is something almost rebellious in the man's posture, as though once faced with the inevitability of death, he decided to get on with it; as though he were a missile, a spear, bent on attaining his own end. He is, fifteen seconds past 9:41 a.m. EST, the moment the picture is taken, in the clutches of pure physics, accelerating at a rate of thirty-two feet per second squared. He will soon be traveling at upwards of 150 miles per hour, and he is upside down. In the picture, he is frozen; in his life outside the frame, he drops and keeps dropping until he disappears.

The photographer is no stranger to history; he knows it is something that happens later. In the actual moment history is made, it is usually made in terror and confusion, and so it is up to people like him -- paid witnesses -- to have the presence of mind to attend to its manufacture. The photographer has that presence of mind and has had it since he was a young man. When he was twenty-one years old, he was standing right behind Bobby Kennedy when Bobby Kennedy was shot in the head. His jacket was spattered with Kennedy's blood, but he jumped on a table and shot pictures of Kennedy's open and ebbing eyes, and then of Ethel Kennedy crouching over her husband and begging photographers -- begging him -- not to take pictures.

Richard Drew has never done that. Although he has preserved the jacket patterned with Kennedy's blood, he has never not taken a picture, never averted his eye. He works for the Associated Press. He is a journalist. It is not up to him to reject the images that fill his frame, because one never knows when history is made until one makes it. It is not even up to him to distinguish if a body is alive or dead, because the camera makes no such distinctions, and he is in the business of shooting bodies, as all photographers are, unless they are Ansel Adams. Indeed, he was shooting bodies on the morning of September 11, 2001. On assignment for the AP, he was shooting a maternity fashion show in Bryant Park, notable, he says, "because it featured actual pregnant models." He was fifty-four years old. He wore glasses. He was sparse in the scalp, gray in the beard, hard in the head. In a lifetime of taking pictures, he has found a way to be both mild-mannered and brusque, patient and very, very quick. He was doing what he always does at fashion shows -- "staking out real estate" -- when a CNN cameraman with an earpiece said that a plane had crashed into the North Tower, and Drew's editor rang his cell phone. He packed his equipment into a bag and gambled on taking the subway downtown. Although it was still running, he was the only one on it. He got out at the Chambers Street station and saw that both towers had been turned into smokestacks. Staking out his real estate, he walked west, to where ambulances were gathering, because rescue workers "usually won't throw you out." Then he heard people gasping. People on the ground were gasping because people in the building were jumping. He started shooting pictures through a 200mm lens. He was standing between a cop and an emergency technician, and each time one of them cried, "There goes another," his camera found a falling body and followed it down for a nine- or twelve-shot sequence. He shot ten or fifteen of them before he heard the rumbling of the South Tower and witnessed, through the winnowing exclusivity of his lens, its collapse. He was engulfed in a mobile ruin, but he grabbed a mask from an ambulance and photographed the top of the North Tower "exploding like a mushroom" and raining debris. He discovered that there is such a thing as being too close, and, deciding that he had fulfilled his professional obligations, Richard Drew joined the throng of ashen humanity heading north, walking until he reached his office at Rockefeller Center.

There was no terror or confusion at the Associated Press. There was, instead, that feeling of history being manufactured; although the office was as crowded as he'd ever seen it, there was, instead, "the wonderful calm that comes into play when people are really doing their jobs." So Drew did his: He inserted the disc from his digital camera into his laptop and recognized, instantly, what only his camera had seen -- something iconic in the extended annihilation of a falling man. He didn't look at any of the other pictures in the sequence; he didn't have to. "You learn in photo editing to look for the frame," he says. "You have to recognize it. That picture just jumped off the screen because of its verticality and symmetry. It just had that look."

He sent the image to the AP's server. The next morning, it appeared on page seven of The New York Times. It appeared in hundreds of newspapers, all over the country, all over the world. The man inside the frame -- the Falling Man -- was not identified.

They began jumping not long after the first plane hit the North Tower, not long after the fire started. They kept jumping until the tower fell. They jumped through windows already broken and then, later, through windows they broke themselves. They jumped to escape the smoke and the fire; they jumped when the ceilings fell and the floors collapsed; they jumped just to breathe once more before they died. They jumped continually, from all four sides of the building, and from all floors above and around the building's fatal wound. They jumped from the offices of Marsh & McLennan, the insurance company; from the offices of Cantor Fitzgerald, the bond-trading company; from Windows on the World, the restaurant on the 106th and 107th floors -- the top. For more than an hour and a half, they streamed from the building, one after another, consecutively rather than en masse, as if each individual required the sight of another individual jumping before mustering the courage to jump himself or herself. One photograph, taken at a distance, shows people jumping in perfect sequence, like parachutists, forming an arc composed of three plummeting people, evenly spaced. Indeed, there were reports that some tried parachuting, before the force generated by their fall ripped the drapes, the tablecloths, the desperately gathered fabric, from their hands. They were all, obviously, very much alive on their way down, and their way down lasted an approximate count of ten seconds. They were all, obviously, not just killed when they landed but destroyed, in body though not, one prays, in soul. One hit a fireman on the ground and killed him; the fireman's body was anointed by Father Mychal Judge, whose own death, shortly thereafter, was embraced as an example of martyrdom after the photograph -- the redemptive tableau -- of firefighters carrying his body from the rubble made its way around the world.

From the beginning, the spectacle of doomed people jumping from the upper floors of the World Trade Center resisted redemption. They were called "jumpers" or "the jumpers," as though they represented a new lemminglike class. The trial that hundreds endured in the building and then in the air became its own kind of trial for the thousands watching them from the ground. No one ever got used to it; no one who saw it wished to see it again, although, of course, many saw it again. Each jumper, no matter how many there were, brought fresh horror, elicited shock, tested the spirit, struck a lasting blow. Those tumbling through the air remained, by all accounts, eerily silent; those on the ground screamed. It was the sight of the jumpers that prompted Rudy Giuliani to say to his police commissioner, "We're in uncharted waters now." It was the sight of the jumpers that prompted a woman to wail, "God! Save their souls! They're jumping! Oh, please God! Save their souls!" And it was, at last, the sight of the jumpers that provided the corrective to those who insisted on saying that what they were witnessing was "like a movie," for this was an ending as unimaginable as it was unbearable: Americans responding to the worst terrorist attack in the history of the world with acts of heroism, with acts of sacrifice, with acts of generosity, with acts of martyrdom, and, by terrible necessity, with one prolonged act of -- if these words can be applied to mass murder -- mass suicide.

Read more at Esquire

Tributes to victims of the 9/11 attacks

The Tribute in Light shines  into the night sky next to the Statue of Liberty and One World Trade Center during events marking the 12th anniversary of the 9/11 attacks on the World Trade Center in New York
The Tribute in Light rises above buildings in lower Manhattan
This year marks the twelfth anniversary of the attacks, but the tenth for the lights themselves. They are made up of 88 individual light sources.
A girl plants some of the 3000 flags placed in memory of the lives lost in the September 11, 2001 attacks, at a park in Winnetka, Illinois
New York Fire Department firefighters Andrew Esposito (L) and his brother Michael Esposito (R) make a rubbing of their father's name, Michael A. Esposito, of the South reflecting pool at the 9/11 Memorial
A photo of New York City Firefighter Robert James Crawford who died in the 2001 attacks, placed by his family as they came to participate in ceremonies for the twelfth anniversary
Michelle Murray of Rockaway, New Jersey looks up while standing at the 9/11 Memorial
A woman touches the stone in New York with names of the 9/11 victims
Daniel Henry, a Port Authority of New York/New Jersey police officer, pauses during a moment of silence at 9:01 am EDT, at the South reflecting pool of the 9/11 Memorial
Two people with shirts commemorating New York City Fire Department firefighter Frankie Esposito sit at the South reflecting pool

See more pictures at The Telegraph

Sep 10, 2013

Think Twice, Speak Once: Bilinguals Process Both Languages Simultaneously

Bilingual speakers can switch languages seamlessly, likely developing a higher level of mental flexibility than monolinguals, according to Penn State linguistic researchers.

"In the past, bilinguals were looked down upon," said Judith F. Kroll, Distinguished Professor of Psychology, Linguistics and Women's Studies. "Not only is bilingualism not bad for you, it may be really good. When you're switching languages all the time it strengthens your mental muscle and your executive function becomes enhanced."

Fluent bilinguals seem to have both languages active at all times, whether both languages are consciously being used or not, the researchers report in a recent issue of Frontiers in Psychology. Both languages are active whether either was used only seconds earlier or several days earlier.

Bilinguals rarely say a word in the unintended language, which suggests that they have the ability to control the parallel activity of both languages and ultimately select the intended language without needing to consciously think about it.

The researchers conducted two separate but related experiments. In the first, 27 Spanish-English bilinguals read 512 sentences, written in either Spanish or English -- alternating language every two sentences. Participants read the sentences silently until they came across a word displayed in red, at which point they were instructed to read the red word out loud, as quickly and accurately as possible. About half of the red words were cognates -- words that look and sound similar and have the same meaning in both languages.

"Cognate words were processed more quickly than control words," said Jason W. Gullifer, a graduate student in psychology, suggesting that both languages are active at the same time.

Participants in the second experiment performed the same tasks as those in the first experiment, but this time were presented one language at a time. The second experiment's results were similar to the first, suggesting that context does not influence word recognition.

Read more at Science Daily

Language Change: From London's 'EastEnders' to Glasgow

A recent study provides the first empirical evidence to show that active and engaged television viewing can help to accelerate language change. The study, "Television can also be a factor in language change: Evidence from an urban dialect," to be published in the September 2013 issue of the journal Language, is authored by Jane Stuart-Smith, English Language/Glasgow University Laboratory of Phonetics, Glasgow University; Claire Timmins, Speech & Language Therapy, Strathclyde University; Gwilym Pryce, Urban Studies, Glasgow University, and Barrie Gunter, Department of Media and Communication, Leicester University. A preprint version is available online at:

This Language study investigated the role of viewing the televised soap opera "East Enders" in the rapid spread of two features of pronunciation typically associated with London English to the dialect of Scotland's largest city, Glasgow. The features are using [f] for /th/ in e.g. think, tooth, and a vowel like that in "good" in place of /l/ in words like milk, and people.

The results show significant correlations between using these features of pronunciation and strong emotional and psychological engagement by the viewers of this TV. "Mere exposure to TV or even this drama is not linked with language change - watching and engaging with the show and its characters is important, not just having the set on, or seeing the show in passing."

The authors caution that television and other forms of popular media constitute only one of many factors that help accelerate language change. "Our study shows that the media can be involved in helping to accelerate changes in relatively subtle aspects of language, which are also well below the level of conscious awareness."

Read more at Science Daily

Bus-Sized Reptile Terrorized Prehistoric Sealife

Mosasaurs, prehistoric marine reptiles that could grow to the size of an 84-seat bus, were much speedier and shark-like than previously thought, an exceptionally well-preserved fossil specimen reveals.

The specimen is in such great shape that it includes soft tissue, according to a paper in the latest Nature Communications. That might open up the possibility of retrieving DNA and cloning the dinosaur-era animal.

For now, scientists are focusing on how surprisingly similar mosasaurs were to sharks both then and now.

“Since both groups occupied similar ecological niches, being top-level carnivores, and lived in similar environments -- i.e., the open sea -- they gradually came to look like each other, so-called convergent evolution,” lead author Johan Lindgren of Lund University’s Department of Geology told Discovery News.

Sharks have existed for hundreds of millions of years, Lindgren said, while mosasaurs lived about 98 to 66 million years ago.

Lindgren and colleagues Hani Kaddumi and Michael Polcyn conducted a detailed analysis of the mosasaur individual, found in what is now central Jordan. The remains include the animal’s crescent-shaped tail and flippers.

These features, plus the mosasaur’s sleek overall body plan, reveal that the toothy predator was built for speed. Until this discovery, researchers thought the animals were not nearly as fast.

“Given that mosasaurs are lizards, they have traditionally been assumed to be lizard-like animals with long, serpentine bodies and paddle-shaped tails, which were capable only of short bursts of speed during brief ambush pursuits,” Lindgren said.

“However, our results clearly demonstrate that mosasaurs underwent the same kind of evolution as did the earlier ichthyosaurs and later whales -- that is, they gradually attained a streamlined body powered by a semiluminate tail fluke. This, in turn, suggests that at least the derived forms were pursuit predators and capable of high-speed swimming over long distances.”

Textbook illustrations of mosasaurs will likely change as a result of this latest research, since earlier drawings made them look more like eels or underwater snakes.

Students might also pay more attention to them in future, since researchers now have such a good fossil record for mosasaur evolution, with nearly every step documented. It’s a bit like looking at a hefty 1920s touring car and then seeing it gradually evolve into a streamlined speed machine.

Being at the top of the food chain, large mosasaurs “were capable of handling virtually anything that came in their way.”

Whales emerged later, so they weren’t a threat. Evidence suggests mosasaurs did battle with sharks, however.

Frank O’Keefe, a Marshall University biologist, has also studied prehistoric marine life.

O’Keefe told Discovery News that the mosasaur ecosystem, aside from sharks, included plesiosaurs (another large now-extinct marine reptile), fish, squid, ammonites and other invertebrates. Mosasaurs might have also encountered toothed birds and pterodactyls, which often hung out near water, hoping for vulnerable prey.

Read more at Discovery News

California Meteorite Carried Rare Life Ingredient

Scientists have discovered unexpected ingredients for life — organic molecules never seen before in meteorites — inside a chunk of space rock that fell to Earth over California last year.

The discovery comes from an analysis of the so-called Sutter's Mill meteorite, which lit up the California night sky with a dazzling fireball in April 2012. Meteorite fragments from the event may shed light on the primordial ooze that helped give rise to life on Earth, researchers said.

Meteors that streak across Earth's sky mostly are fragments of the asteroids that lie between Mars and Jupiter. Meteorites can be rich in organic compounds, including some found among life on Earth.

"Their composition therefore has always been seen as an indication that the precursors to the evolution that led to the origins of life could have come from the extraterrestrial material of meteorites," study lead author Sandra Pizzarello, a biochemist at Arizona State University in Tempe, told "Since the origins of life are utterly unknown, the idea has its merits."

Pizzarello and her colleagues analyzed two fragments of the Sutter's Mill meteorite, which streaked through the skies on April 22, 2012, crashing in California. Fragments of this meteorite were given to researchers who have worked on similar rocks before, including Pizzarello.

The organic chemicals in meteorites can get extracted with the aid of solvents. Speculation regarding the origin of life is based on the notion that it arose from a "prebiotic" soup of organic molecules, perhaps delivered in part by meteorites. Initially, fragments of the Sutter's Mill meteorite apparently possessed fewer dissolvable organic compounds left after solvent extraction compared to other similar meteorites.

"You may say that it was a disappointment," Pizzarello said.

However, the researchers tried dissolving the fragments in conditions mimicking hydrothermal vents on Earth, the environment often seen in the early Earth that life might have arisen within. Upon such treatment, the rocks released organic molecules not previously detected in similar meteorites. The findings that suggest there are far more organic materials available via meteorite for planetary environments than scientists assumed.

Read more at Discovery News

Sep 9, 2013

Hubble Bubble May Explain Different Measurements of Expansion Rate of the Universe

The existence of the "Hubble Bubble" may explain, at least in part, the differing measurements for the expansion and therefore the age of the universe. That is the assumption of a team of physicists headed by Prof. Dr. Luca Amendola from the Institute for Theoretical Physics at Heidelberg University. In collaboration with colleagues from the Netherlands, the Heidelberg physicists developed a theoretical model that places the Milky Way inside of this type of cosmic bubble. The researchers believe the bubble can explain some of the deviations between previous measurements and the latest ones from the Planck satellite of the European Space Agency (ESA).

The results of their research were published in the journal Physical Review Letters.

The observable universe has been expanding since the Big Bang. It still is, causing galaxies beyond our Local Group to appear to be receding from us. The actual speed of this expansion is known as the Hubble constant. Due to its importance in calculating basic properties of the universe, such as its age, modern cosmology is tasked with determining the value of the constant. There are two conventional methods used, although their results are not congruent, according to Dr. Valerio Marra from Heidelberg University's Institute for Theoretical Physics. "This has been the source of intense, long-standing debate in the scientific community."

One way to determine the Hubble constant, and hence the universe's rate of expansion, is based on measuring the cosmic microwave background radiation in space. It was released approximately 400,000 years after the Big Bang and pervades the entire universe. Several months ago the Planck satellite from the ESA delivered measurements of this ancient radiation. The Hubble constant, however, can also be derived from the movement of galaxies near the Milky Way, movement largely due to the expansion of the universe. "When you compare the results from the two methods, there is a deviation of about 9 percent," explains Dr. Marra.

In their search to explain the difference in data, the Heidelberg team thought that the reason was not some previously unrecognized error in measurement, but based on a physical effect. According to Dr. Marra, the existence of the Hubble Bubble could be the cause. The bubble describes regions of the universe where the density of matter falls below the cosmic average. "Until now knowledge of our cosmic neighbourhood has been too imprecise to determine whether or not we are in such a bubble," continues Dr. Marra. "But let's just assume for a moment that our Milky Way is located in a Hubble Bubble. Matter outside the bubble would then attract nearby galaxies so strongly that they would move more quickly than average. In this case we would measure a higher Hubble constant that would apply to our cosmic neighbourhood, but not to the universe as a whole."

Dr. Marra believes that this could partly explain the conflicting measurement results. The Hubble constant measured by the Planck satellite would represent a spatial average applicable to the entire universe. The Hubble constant determined through the movement of galaxies, however, would be valid only in the vicinity of the Milky Way. "Anyone expecting the measurements from our cosmic environs to match those of the microwave radiation implicitly assumes that we live in a typical region of the cosmos. But that isn't necessarily true," continues Prof. Amendola, whose working group has been studying the expansion of the universe for many years.

Using their research approach, the scientists have thus far been able to account for approximately one-fourth of the deviation between the two Hubble constants. Dr. Marra and his colleagues expect a detailed analysis will reduce the discrepancy even more. "Until now we have been working with a spherical Hubble Bubble. But it's far more likely that the bubble is asymmetrical, which would explain the deviating measurements even better," observes Dr. Ignacy Sawicki, also a researcher at the Institute for Theoretical Physics. "If the difference in data should manifest itself instead, this would be a major indicator that our former natural scientific view of the cosmos is still missing an ingredient," stresses Dr. Sawicki.

Read more at Science Daily

Ancient Golden Treasure Found at Foot of Temple Mount

In summer excavations at the foot of the Temple Mount, Hebrew University of Jerusalem archaeologist Dr. Eilat Mazar made a stunning discovery: two bundles of treasure containing thirty-six gold coins, gold and silver jewelry, and a gold medallion with the menorah (Temple candelabrum) symbol etched into it. Also etched into the 10-cm medallion are a shofar (ram's horn) and a Torah scroll.

A third-generation archaeologist working at the Hebrew University's Institute of Archaeology, Dr. Mazar directs excavations on the City of David's summit and at the Temple Mount's southern wall. Calling the find "a breathtaking, once-in-a-lifetime discovery," Dr. Mazar said: "We have been making significant finds from the First Temple Period in this area, a much earlier time in Jerusalem's history, so discovering a golden seven-branched Menorah from the seventh century CE at the foot of the Temple Mount was a complete surprise."

The discovery was unearthed just five days into Mazar's latest phase of the Ophel excavations, and can be dated to the late Byzantine period (early seventh century CE). The gold treasure was discovered in a ruined Byzantine public structure a mere 50 meters from the Temple Mount's southern wall.

The menorah, a candelabrum with seven branches that was used in the Temple, is the national symbol of the state of Israel and reflects the historical presence of Jews in the area. The position of the items as they were discovered indicates that one bundle was carefully hidden underground while the second bundle was apparently abandoned in haste and scattered across the floor.

Given the date of the items and the manner in which they were found, Mazar estimates they were abandoned in the context of the Persian conquest of Jerusalem in 614 CE. After the Persians conquered Jerusalem, many Jews returned to the city and formed the majority of its population, hoping for political and religious freedom. But as Persian power waned, instead of forming an alliance with the Jews, the Persians sought the support of Christians and ultimately allowed them to expel the Jews from Jerusalem.

Hanging from a gold chain, the menorah medallion is most likely an ornament for a Torah scroll. In that case it is the earliest Torah scroll ornament found in archaeological excavations to date. It was buried in a small depression in the floor, along with a smaller gold medallion, two pendants, a gold coil and a silver clasp, all of which are believed to be Torah scroll ornamentations.

"It would appear that the most likely explanation is that the Ophel cache was earmarked as a contribution toward the building of a new synagogue, at a location that is near the Temple Mount," said Dr. Mazar. "What is certain is that their mission, whatever it was, was unsuccessful. The treasure was abandoned, and its owners could never return to collect it."

The Ophel cache is only the third collection of gold coins to be found in archaeological excavations in Jerusalem, said Lior Sandberg, numismatics specialist at the Institute of Archaeology. "The thirty-six gold coins can be dated to the reigns of different Byzantine emperors, ranging from the middle of the fourth century CE to the early seventh century CE," said Sandberg.

Found with the coins were a pair of large gold earrings, a gold-plated silver hexagonal prism and a silver ingot. Remnants of fabric indicated that these items were once packaged in a cloth purse similar to the bundle that contained the menorah medallion.

Mazar's Ophel excavation made headlines earlier this year when she announced the 2012 discovery of an ancient Canaanite inscription (recently identified as Hebrew), the earliest alphabetical written text ever uncovered in Jerusalem.

The 2013 excavation season at the Ophel ran from the middle of April to the end of July, on behalf of the Institute of Archaeology of the Hebrew University. The Israel Antiquities Authority is carrying out the preservation works, and is preparing the site for the public. The excavation site is situated within the Jerusalem National Park around the walls of Jerusalem of the Israel Nature and Parks Authority, and is administered by the East Jerusalem Development Company.

Read more at Science Daily

NASA's Black-Hole-Hunter Catches Its First 10 Supermassive Black Holes

NASA's black-hole-hunter spacecraft, the Nuclear Spectroscopic Telescope Array, or NuSTAR, has "bagged" its first 10 supermassive black holes. The mission, which has a mast the length of a school bus, is the first telescope capable of focusing the highest-energy X-ray light into detailed pictures.

The new black-hole finds are the first of hundreds expected from the mission over the next two years. These gargantuan structures -- black holes surrounded by thick disks of gas -- lie at the hearts of distant galaxies between 0.3 and 11.4 billion light-years from Earth.

"We found the black holes serendipitously," explained David Alexander, a NuSTAR team member based in the Department of Physics at Durham University in England and lead author of a new study appearing Aug. 20 in The Astrophysical Journal. "We were looking at known targets and spotted the black holes in the background of the images."

Additional serendipitous finds such as these are expected for the mission. Along with the mission's more targeted surveys of selected patches of sky, the NuSTAR team plans to comb through hundreds of images taken by the telescope with the goal of finding black holes caught in the background.

Once the 10 black holes were identified, the researchers went through previous data taken by NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton satellite, two complementary space telescopes that see lower-energy X-ray light. The scientists found that the objects had been detected before. It wasn't until the NuSTAR observations, however, that they stood out as exceptional, warranting closer inspection.

By combining observations taken across the range of the X-ray spectrum, the astronomers hope to crack unsolved mysteries of black holes. For example, how many of them populate the universe?

"We are getting closer to solving a mystery that began in 1962," said Alexander. "Back then, astronomers had noted a diffuse X-ray glow in the background of our sky but were unsure of its origin. Now, we know that distant supermassive black holes are sources of this light, but we need NuSTAR to help further detect and understand the black hole populations."

This X-ray glow, called the cosmic X-ray background, peaks at the high-energy frequencies that NuSTAR is designed to see, so the mission is key to identifying what's producing the light. NuSTAR can also find the most hidden supermassive black holes, buried by thick walls of gas.

"The highest-energy X-rays can pass right through even significant amounts of dust and gas surrounding the active supermassive black holes," said Fiona Harrison, a study co-author and the mission's principal investigator at the California Institute of Technology, Pasadena.

Data from NASA's Wide-field Infrared Survey Explorer, or WISE, and Spitzer missions also provide missing pieces in the puzzle of black holes by weighing the mass of their host galaxies.

"Our early results show that the more distant supermassive black holes are encased in bigger galaxies," said Daniel Stern, a co-author of the study and the project scientist for NuSTAR at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This is to be expected. Back when the universe was younger, there was a lot more action with bigger galaxies colliding, merging and growing."

Future observations will reveal more about the beastly happenings of black holes, near and far. In addition to hunting remote black holes, NuSTAR is also searching for other exotic objects within our Milky Way galaxy.

NuSTAR is a Small Explorer mission led by the California Institute of Technology in Pasadena and managed by NASA's Jet Propulsion Laboratory, also in Pasadena, for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.

Read more at Science Daily

Rescued Kitten Infected Girl With Rare Virus

A teenager in the Netherlands who rescued a drowning kitten from a ditch developed a large, blackened open wound on her wrist, which took multiple doctors several weeks to find its rare cause, researchers say.

The kitten that the girl rescued was sick and died the following day, and the 17-year-old went on a trip to Italy and Switzerland, during which time she developed a red wound on her wrist that blistered before turning black. She also developed painful red bumps on her arm, spanning from the wound on her wrist up to her armpit.

Suspecting the wound was a bacterial infection, doctors prescribed antibiotics, but the medicine didn't work. Once back in her home country, the feverish girl went to the hospital again.

"When I saw the wound, I expected it to be a normal wound, so I was quite surprised when I saw the big ulcer," said Dr. Jojanneke Heidema, a specialist in pediatric infectious disease at St. Antonius Ziekenhuis Hospital in Nieuwegein, Netherlands, who reported the case.

"It did not look like a normal bacterial infection, so I went looking for other causes of a necrotic ulcer," Heidema said. Necrotic ulcers are wounds with dead tissue.

The doctors began to suspect that the wound was caused by the cowpox virus. The cowpox infection is so rare that physicians sometimes have never even seen one, or simply don't think of it.

The doctors got in touch with a virologist whose lab was equipped to run tests for cowpox. A few days later, lab results proved the cowpox virus was, indeed, the culprit. "The girl had been treated by different doctors for about 13 days by then," Heidema said.

After another week, the girl got better on her own, and the wound healed within two months, leaving a scar. Cowpox is a self-limiting disease, meaning it usually doesn't need medical treatment.

"In cowpox disease, your own immune system will deal with the infection," Heidema said.

The cowpox virus was involved in the invention of the first vaccine, against the related virus that causes smallpox, the deadly but now eradicated disease. At the end of the 18th century, Edward Jenner, an English physician, observed that milkmaids who had contact with the cattle-carrying cowpox virus rarely contracted smallpox -- they seemed protected. Based on this observation, Jenner used the cowpox virus to produce the first smallpox vaccine, in 1796.

Other than cowpox, some possible causes of a necrotic wound like the one the girl had were drug-resistant bacteria, abscess and anthrax, the researchers said.

Read more at Discovery News

Sep 8, 2013

Quantum chip connected to internet is yours to command

Quantum computing is in the cloud, and you don't need a degree in advanced physics to run your own programs. For the first time, anyone with a web browser will soon be able to log in and run basic algorithms on a quantum chip hooked up to the internet.

A quantum chip processes information in qubits, or quantum bits, which, unlike the digital bits in a regular computer, can be both 0 and 1 at the same time. In theory, this ability should allow quantum computers to offer far speedier computation than current PCs – although devices that can definitely outperform standard machines don't yet exist.

Until now only a few labs around the world have had access to even basic quantum computers. Google recently purchased a D-Wave quantum computer and shares access with NASA and other select researchers, but not with the general public. Questions also remain over just how quantum D-Wave's machine really is, because it operates using a non-mainstream technique called adiabatic quantum computing.

Scientists at the University of Bristol, UK, were concerned that limited availability to any type of quantum computer would mean a dearth of skilled coders when the expected quantum revolution finally arrives.

"A quantum computer can do things faster for you, but someone has to program it, and at the moment there are only a handful of people around the world who would be qualified," says Bristol's Jeremy O'Brien, who led the development of the quantum chip being used in the cloud project.

Quantum sim

The more traditionally quantum chip made at the University of Bristol works by guiding two photons through a series of optical channels. As the photons pass through the chip they become entangled, meaning that a measurement on one influences the outcome when measuring the other. Programming the computer involves tweaking the extent of this entanglement to produce different computations.

Would-be quantum coders will first use an online simulator that lets them practise programming. A tutorial explains the key quantum-mechanical ideas that are central to the device, then guides users through the steps required to adjust the chip and change its output. Once experienced enough, users can ask for permission to connect to the real chip, which is sitting in a lab in Bristol. It will run programs and return results via the internet.

"You can sit on the bus with your mobile phone and do a quantum optics experiment which might never have been seen before," says team member Peter Shadbolt. The simulator is already online, but the ability to directly access the chip won't launch until 20 September.

Cloudy future

Exactly what a member of the public might want to use the quantum chip for is unclear. And the version being used online only has two qubits, so its processing power is a very limited.

"It's not going to calculate something that your PC couldn't calculate, because it's not at that scale by a long way," says O'Brien. His team has made 6-qubit and 8-qubit computers, but those projects are still in development. In the meantime, they are happy to let others use their older technology for free as a way to encourage engagement.

Read more at New Scientist

Climate Change Will Upset Vital Ocean Chemical Cycles

New research from the University of East Anglia shows that rising ocean temperatures will upset natural cycles of carbon dioxide, nitrogen and phosphorus.

Plankton plays an important role in the ocean's carbon cycle by removing half of all CO2 from the atmosphere during photosynthesis and storing it deep under the sea -- isolated from the atmosphere for centuries.

Findings published today in the journal Nature Climate Change reveal that water temperature has a direct impact on maintaining the delicate plankton ecosystem of our oceans.

The new research means that ocean warming will impact plankton, and in turn drive a vicious cycle of climate change.

Researchers from UEA's School of Environmental Sciences and the School of Computing Sciences investigated phytoplankton -- microscopic plant-like organisms that rely on photosynthesis to reproduce and grow.

Lead researcher Dr Thomas Mock, said: "Phytoplankton, including micro-algae, are responsible for half of the carbon dioxide that is naturally removed from the atmosphere. As well as being vital to climate control, it also creates enough oxygen for every other breath we take, and forms the base of the food chain for fisheries so it is incredibly important for food security.

"Previous studies have shown that phytoplankton communities respond to global warming by changes in diversity and productivity. But with our study we show that warmer temperatures directly impact the chemical cycles in plankton, which has not been shown before."

Collaborators from the University of Exeter, who are co-authors of this study, developed computer generated models to create a global ecosystem model that took into account world ocean temperatures, 1.5 million plankton DNA sequences taken from samples, and biochemical data.

"We found that temperature plays a critical role in driving the cycling of chemicals in marine micro-algae. It affects these reactions as much as nutrients and light, which was not known before," said Dr Mock.

"Under warmer temperatures, marine micro-algae do not seem to produce as many ribosomes as under lower temperatures. Ribosomes join up the building blocks of proteins in cells. They are rich in phosphorus and if they are being reduced, this will produce higher ratios of nitrogen compared to phosphorus, increasing the demand for nitrogen in the oceans.

Read more at Science Daily