Earth's Iron Core Is Surprisingly Weak

Researchers have used a diamond anvil cell to squeeze iron at pressures as high as 3 million times that felt at sea level to recreate conditions at the center of Earth. The findings could refine theories of how the planet and its core evolved.

Through laboratory experiments, postdoctoral researcher Arianna Gleason, left, and Wendy Mao, an assistant professor of geological and environmental sciences and of photon science, determined that the iron in Earth's inner core is about 40 percent as strong as previously believed.

The massive ball of iron sitting at the center of Earth is not quite as "rock-solid" as has been thought, say two Stanford mineral physicists. By conducting experiments that simulate the immense pressures deep in the planet's interior, the researchers determined that iron in Earth's inner core is only about 40 percent as strong as previous studies estimated.

This is the first time scientists have been able to experimentally measure the effect of such intense pressure -- as high as 3 million times the pressure Earth's atmosphere exerts at sea level -- in a laboratory. A paper presenting the results of their study is available online in Nature Geoscience.

"The strength of iron under these extreme pressures is startlingly weak," said Arianna Gleason, a postdoctoral researcher in the department of Geological and Environmental Sciences, and lead author of the paper. Wendy Mao, an assistant professor in the department, is the co-author.

"This strength measurement can help us understand how the core deforms over long time scales, which influences how we think about Earth's evolution and planetary evolution in general," Gleason said.

Until now, almost all of what is known about Earth's inner core came from studies tracking seismic waves as they travel from the surface of the planet through the interior. Those studies have shown that the travel time through the inner core isn't the same in every direction, indicating that the inner core itself is not uniform. Over time and subjected to great pressure, the core has developed a sort of fabric as grains of iron elongate and align lengthwise in parallel formations.

The ease and speed with which iron grains in the inner core can deform and align would have influenced the evolution of the early Earth and development of the geomagnetic field. The field is generated by the circulation of liquid iron in the outer core around the solid inner core and shields Earth from the full intensity of solar radiation. Without the geomagnetic field, life -- at least as we know it -- would not be possible on Earth.

"The development of the inner core would certainly have some effect on the geomagnetic field, but just what effect and the magnitude of the effect, we can't say," said Mao. "That is very speculative."

Gleason and Mao conducted their experiments using a diamond anvil cell -- a device that can exert immense pressure on tiny samples clenched between two diamonds. They subjected minute amounts of pure iron to pressures between 200 and 300 gigapascals (equivalent to the pressure of 2 million to 3 million Earth atmospheres). Previous experimental studies were conducted in the range of only 10 gigapascals.

"We really pushed the limit here in terms of experimental conditions," Gleason said. "Pioneering advancements in pressure-generation techniques and improvements in detector sensitivity, for example, used at large X-ray synchrotron facilities, such as Argonne National Lab, have allowed us to make these new measurements."

In addition to intense pressures, the inner core also has extreme temperatures. The boundary between the inner and outer core has temperatures comparable to the surface of the sun. Simultaneously simulating both the pressure and temperature at the inner core isn't yet possible in the laboratory, though Gleason and Mao are working on that for future studies. (For this study, Gleason mathematically extrapolated from their pressure data to factor in the effect of temperature.)

Read more at Science Daily

How Penguins Lost Their Ability to Fly

Penguins lost their ability to fly millions of years ago, and now a new study explains why -- the birds became lean and mean diving machines, trading flight for such skills.

The study, published in the latest Proceedings of the National Academy of Sciences, points out that good flippers don’t fly very well.

"Once penguins gave up flight, changes to wing structure and overall body size and shape probably followed rapidly because flying no longer placed constraints to body form," co-author Robert Ricklefs told Discovery News.

"Note that penguins are much more at risk of predation in the water than they are on land, and so there has been strong selection to make their swimming and diving as efficient as possible," added Ricklefs, who is a professor of biology at the University of Missouri at St. Louis.

Ricklefs, lead author Kyle Elliott and their team at first wondered why the ubiquitous black and white birds lost their ability to fly millions of years ago, given how beneficial flying can be. Emperor penguins laboriously walk over 32 miles between their rookeries and the sea. The journey takes them several days, which could be reduced to just a few hours if they could fly. Why then don’t they?

To solve the mystery, the researchers focused on birds-- especially the murre -- that both fly and dive. The scientists equipped 41 such wild-caught birds with equipment to measure avian energy expenditure. In doing so, the researchers came up with a new world’s record. Murres and pelagic cormorants turn out to have the highest expenditure ever recorded for any flying animal.

"The costs are incurred in providing lift in air," Ricklefs explained, adding that overcoming drag in the air is also energy costly to the birds.

While murres can both fly and dive, there appears to be a threshold where one activity overtakes the other in evolution. If a bird needs to fly more, it will lose more of its diving and swimming ability. Conversely, if a bird greatly relies upon swimming and diving for its hunting and survival, then it will tend to lose its flight skills. In the case of penguins, those skills completely disappeared, with the wings evolving into marine mammal-type flippers.

The study also sheds light on what prehistoric flying penguins looked and acted like.

"The flying ancestors of penguins were probably not much different in general appearance than murres and their relatives, and probably behaved in much the same way," Ricklefs said.

The findings could help explain how other birds lost their ability to fly. There is a flightless cormorant in the Galapagos Islands, and steamer ducks of the southern oceans are also flightless.

The reasons for flightlessness are different for ostriches and emus, which do not dive. These big birds instead traded flight for running ability. It’s likely that the ancestors of ostriches and emus did not have to migrate. They perhaps lived in the southern continents with relative few predators. Running with their powerful legs sufficed, versus needing to rely upon flight to take them up and away.

Tony Diamond of the University of New Brunswick, James Lovvorn at Southern Illinois University, and Daniel Roby of the Department of Fisheries and Wildlife all told Discovery News that they agree with the conclusions of the new study.

Read more at Discovery News

Edward Scissorhands Fossil Found

An Edward Scissorhands-like fossil has emerged from a national park in Canada,  British researchers reported.

Found in the valley of the Stanley Glacier, in Kootenay National Park, British Columbia, the newly discovered species features the body structure of a 505 million-year-old sea creature with scissor-like claws.

“When I first saw the pair of isolated claws in the fossil records of this species I could not help but think of Edward Scissorhands,” David Legg, who made the discovery while working on his Ph.D. at Imperial College London, said in a statement.

Legg, who detailed the finding in the Journal of Palaeontology, decided to name the new species Kooteninchela deppi (pronounced Koo-ten-ee-che-la depp-eye) in honor of Johnny Depp’s starring role in the 1990 cult movie.

Directed by Tim Burton, the movie was about an artificial man named Edward, built by an inventor who died before giving him hands. This meant he was left with a set of blades in the place of fingers.

“Even the genus name, Kootenichela, includes the reference to this film as ‘chela’ is Latin for claws or scissors. In truth, I am also a bit of a Depp fan,” Legg said.

An ancestor to lobsters and scorpions, Kooteninchela deppi roamed the sea about 270 million years before dinosaurs actually began to appear.

Less than two inches long with an elongate, multi-segmented body and millipede-like legs, the creature boasted large compound eyes similar to that of a fly. These eyes were located on top of movable stalks called peduncles, helping the creature to more easily search for food and look out for predators.

Over half a billion years ago, the cost of British Columbia in Canada was located much closer to the equator and the sea temperature would have been much warmer than it is today.

Living in very shallow seas among wild sponges, the tiny creature — a hunter or scavenger — used its multiple legs to scuttle along the sea floor. According to Legg, its large Edward Scissorhands-like claws and the long spines that enhanced them helped to grab prey or scour the sea floor for creatures hiding there.

Belonging to a group called the “great-appendage” arthropods, or megacheirans, in reference to the enlarged pincer-like frontal claws that they share, Kooteninchela deppi is helping researchers to understand more about life on Earth during the Cambrian period, when nearly all modern animal types emerged.

Read more at Discovery News

Could Humans Be Cloned?

The news that researchers have used cloning to make human embryos for the purpose of producing stem cells may have some people wondering if it would ever be possible to clone a person.

Although it would be unethical, experts say it is likely biologically possible to clone a human being. But even putting ethics aside, the sheer amount of resources needed to do it is a significant barrier.

Since the 1950s when researchers cloned a frog, scientists have cloned dozens of animal species, including mice, cats, sheep, pigs and cows.

In each case, researchers encountered problems that needed to be overcome with trial and error, said Dr. Robert Lanza, chief scientific officer at the biotech company Advanced Cell Technology, which works on cell therapies for human diseases, and has cloned animals.

With mice, researchers were able to use thousands of eggs, and conduct many experiments, to work out these problems, Lanza said. "It’s a numbers game," he said.

But with primates, eggs are a very precious resource, and it is not easy to acquire them to conduct experiments, Lanza said.

In addition, researchers can't simply apply what they've learned from cloning mice or cows to cloning people.

For instance, cloning an animal requires that researchers first remove the nucleus of an egg cell. When researchers do this, they also remove proteins that are essential to help cells divide, Lanza said. In mice, this isn't a problem, because the embryo that is ultimately created is able to make these proteins again. But primates aren't able to do this, and researchers think it may be one reason that attempts to clone monkeys have failed, Lanza said.

What's more, cloned animals often have different kinds of genetic abnormalities that can prevent embryo implantation in a uterus, or cause the fetus to spontaneously abort, or the animal to die shortly after birth, Lanza said.

These abnormities are common because cloned embryos have just one parent rather than two, which means that a molecular process known as "imprinting" does not occur properly in cloned embryos, Lanza said. Imprinting takes place during embryo development, and selectively silences certain genes from one parent or the other.

Read more at Discovery News

Reading Rock to Understand How Climate Change Unfolds

What happened the last time a vegetated Earth shifted from an extremely cold climate to desert-like conditions? And what does it tell us about climate change today?

John Isbell is on a quest to coax that information from the geology of the southernmost portions of the Earth. It won't be easy, because the last transition from "icehouse to greenhouse" occurred between 335 and 290 million years ago.

An expert in glaciation from the late Paleozoic Era, Isbell is challenging many assumptions about the way drastic climate change naturally unfolds. The research helps form the all-important baseline needed to predict what the added effects of human activity will bring.

Starting from 'deep freeze'

In the late Paleozoic, the modern continents were fused together into two huge land masses, with what is now the Southern Hemisphere, including Antarctica, called Gondwana. During the span of more than 60 million years, Gondwana shifted from a state of deep freeze into one so hot and dry it supported the appearance of reptiles. The change, however, didn't happen uniformly, Isbell says.

In fact, his research has shaken the common belief that Gondwana was covered by one massive sheet of ice which gradually and steadily melted away as conditions warmed. Isbell has found that at least 22 individual ice sheets were located in various places over the region. And the state of glaciation during the long warming period was marked by dramatic swings in temperature and atmospheric carbon dioxide (CO2) levels.

"There appears to be a direct association between low CO2 levels and glaciation," he says. "A lot of the changes in greenhouse gases and in a shrinking ice volume then are similar to what we're seeing today."

When the ice finally started disappearing, he says, it did so in the polar regions first and lingered in other parts of Gondwana with higher elevations. He attributes that to different conditions across Gondwana, such as mountain-building events, which would have preserved glaciers longer.

All about the carbon

To get an accurate picture of the range of conditions in the late Paleozoic, Isbell has traveled to Antarctica 16 times and has joined colleagues from around the world as part of an interdisciplinary team funded by the National Science Foundation. They have regularly gone to places where no one has ever walked on the rocks before.

One of his colleagues is paleoecologist Erik Gulbranson, who studies plant communities from the tail end of the Paleozoic and how they evolved in concert with the climatic changes. The information contained in fossil soil and plants, he says, can reveal a lot about carbon cycling, which is so central for applying the work to climate change today.

Documenting the particulars of how the carbon cycle behaved so long ago will allow them to answer questions like, 'What was the main force behind glaciation during the late Paleozoic? Was it mountain-building or climate change?'

Another characteristic of the late Paleozoic shift is that once the climate warmed significantly and atmospheric CO2 levels soared, the Earth's climate remained hot and dry for another 200 million years.

"These natural cycles are very long, and that's an important difference with what we're seeing with the contemporary global climate change," says Gulbranson. "Today, we're seeing change in greenhouse gas concentrations of CO2 on the order of centuries and decades."

Ancient trees and soil

In order to explain today's accelerated warming, Gulbranson's research illustrates that glaciers alone don't tell the whole story.

Many environmental factors leave an imprint on the carbon contained in tree trunks from this period. One of the things Gulbranson hypothesizes from his research in Antarctica is that an increase in deciduous trees occurred in higher latitudes during the late Paleozoic, driven by higher temperatures.

What he doesn't yet know is what the net effect was on the carbon cycle.

While trees soak in CO2 and give off oxygen, there are other environmental processes to consider, says Gulbranson. For example, CO2 emissions also come from soil as microbes speed up their consumption of organic matter with rising temperatures.

"The high latitudes today contain the largest amount of carbon locked up as organic material and permafrost soils on Earth today," he says. "It actually exceeds the amount of carbon you can measure in the rain forests. So what happens to that stockpile of carbon when you warm it and grow a forest over it is completely unknown."

Another unknown is whether the Northern Hemisphere during this time was also glaciated and warming. The pair are about to find out. With UWM backing, they will do field work in northeastern Russia this summer to study glacial deposits from the late Paleozoic.

Read more at Science Daily

Frogs, Salamanders and Climate Change

By day, insects provide the white noise of the South, but the night belongs to the amphibians. In a typical year, the Southern air hangs heavy from the humidity and the sounds of wildlife. The Southeast, home to more than 140 species of frogs, toads and salamanders, is the center of amphibian biodiversity in our nation. If the ponds and swamps are the auditorium for their symphonic choruses, the scientists of the U.S. Geological Survey's Amphibian Research and Monitoring Initiative, or ARMI, have front-row seats.

Amphibians, which rely on water for part or all of their life cycle, must adjust to often atypical weather. Some years bring heavy deluges, such as the region's notorious hurricanes, and others bring the transformations that come with drought. Amphibians around the world seem to be experiencing the worst declines documented among vertebrates. While habitat loss is the number one reason for population declines, research suggests that disease, invasive species, contaminants and perhaps other factors contribute to declines in protected areas.

And then there's climate change, another stressor for amphibians to contend with. Climate change projections indicate that rainfall will increasingly come in pulses, with greater deluges and longer periods of drought. Scientists have long suspected that climate change is an important factor in amphibian declines, and resource managers are asking whether conservation measures might help species persist or adapt in a changing climate. Three recent U.S. Geological Survey studies offer some insight into the issue.

Why amphibians?

Amphibians, which are declining throughout the world, play an important role in ecological systems. They eat small creatures, including mosquitos, and they are food themselves for larger creatures, such as birds and snakes. Because amphibians are the middle of the food chain -- and sensitive to environmental disruption because of their aquatic or semi-aquatic lives -- their existence is often used as an indication of ecosystem health.

Scientists in ARMI, a program started by Congress in 2000 in response to concerns about amphibian declines, have been working to unravel the ups and downs of amphibian populations to support effective conservation and resource management decisions. To do this, ARMI scientists and field crews monitor the status of amphibians, research the causes of declines, and scientifically evaluate projects undertaken to sustain these species and their habitats across the country.

Pond life -- it's not easy being green!

ARMI scientists looked at a range of amphibian species found in the Southeast and posed the question, "What will happen to their populations under a scenario of changes in rainfall patterns -- more deluges alternating with droughts -- which is being predicted by current climate models?"

It turns out that understanding how climate affects amphibians requires "thinking like the ponds" in which they live. Amphibians have unique life cycles -- most alternate between living in water as juveniles, to maturing and dispersing on land, then returning to water again as adults to mate and lay eggs.

When USGS scientists reviewed what was known about amphibian responses to rainfall, it turned out that both extremes in rainfall -- drought and heavy rainfall events -- can decrease the number of amphibians. The amphibians' response depends on a balance between these two key factors. If ponds dry up while aquatic juveniles are developing, survival of the next generation is lowered. However, if a deluge occurs at that time, nearby pools that often contain fish will be physically connected with the pools containing juvenile amphibians, and the fish will eat the juveniles.

In essence, the study showed that extreme rainfall events are key to predicting amphibian responses to climate, because such events affect the amount and timing of water in ponds that they depend on. The full review of species' responses was published in March 2013 edition of the journal Biology.

Drought and declining salamanders

Knowing that each species responds to droughts and deluges based on the particulars of their biology, scientists set out to test just how these dynamics played out in the southeastern U.S. by looking at larval mole salamanders in small isolated ponds in St. Mark's National Wildlife Refuge, Florida.

Larval mole salamanders have a similar life cycle to the flatwoods salamander, a federally threatened species found on the refuge. Because it is difficult to study the flatwoods salamander directly, and mole salamanders are ecologically similar, scientists study the mole salamander instead, knowing that whatever affects them will likely impact the flatwoods salamander as well.

In the four years of the study, drought consistently decreased salamander occupancy in ponds. To support young salamanders, rain has to fill a pond during the breeding season and then the pond has to stay filled long enough for larvae to transform into the next life stage. Therefore, scientists confirmed that drought did indeed cause short-term declines in mole salamanders -- suggesting that the listed flatwoods salamander may face a similar fate under climate change.

The results of the mole salamander study are published in the April 2013 edition of the journal Wetlands.

Can habitat conservation make a difference for frogs and toads?

To answer this question, USGS scientists examined whether the U.S. Department of Agriculture's Natural Resources Conservation Service Wetlands Reserve Program was helping address the problem. The Wetlands Reserve Program is a voluntary USDA program offering landowners the opportunity to protect, restore, and enhance wetlands on their property. To assess the potential benefit of WRP restoration to amphibians, in this case, frogs and toads, USGS scientists surveyed 30 randomly selected WRP sites and 20 nearby agricultural sites in the Mississippi Delta in northwest Mississippi.

Read more at Science Daily

Watch the Biggest Explosion Ever Seen on the Moon

NASA scientists recorded the biggest explosion from a meteorite impact seen on the moon in eight years of monitoring.

The lunar burst was caused by a 40-kilogram boulder-sized rock slamming into the surface at about 90,000 kph. It generated a flash 10 times brighter than anything seen before, which came from the thermal glow of molten rock at the point of impact.

The moon, like most bodies in the solar system, is subject to relatively frequent bombardment by small space rocks. Most of these objects are fairly tiny, pebble-sized or smaller, but in 2005 NASA set up a specific program to identify how often they occur. The lunar impact team has since identified more than 300 explosions, most of them faint and usually happening at the same time as a meteor shower on Earth. Researchers want to know how often they can expect such impacts, which could come in handy when planning moonwalks during future astronaut trips to our satellite.

The March 17 impact created a blast that was bright enough to be seen from Earth with the naked eye. It may have generated a crater roughly 20 meters wide, which could be imaged by the Lunar Reconnaissance Orbiter next time it passes over the area, allowing researchers to see a very fresh impact on the moon.

From Wired Science

How science takes the Bible to bits

Steve Jones's scientific retelling of the Bible in The Serpent's Promise is lively and amusing, but it is hard to tell what audience the book is intended for

Where does the idea of a single soul at conception leave twins?

THE Bible has been called "the greatest story ever told". Steve Jones begs to differ. In The Serpent's Promise, Jones, a British geneticist and outspoken anti-religionist, sets out to retell the Bible from the point of view of science.

Well, not exactly. Instead of a point-by-point fact-checking of the Christian holy book, Jones has opted to pick some of its main themes. From big topics such as the origins of the world and of humans, Noah's flood and other epic disasters, and the ultimate fate of Earth, he sketches out our scientific knowledge for each.

Sometimes this works well. The chapter on origins, for example, takes a quick tour through the big bang, the formation of Earth, the history of the continents, the origin of life, its evolutionary history, plus human evolution – and all in less than 40 pages.

Needless to say, Jones is aiming to hit the high points, not provide a comprehensive lesson. But it all hangs together, and it gives a fair overview of science's alternative to the first chapters of Genesis.

At other times, though, this approach seems to be little more than an excuse for rambling. For instance, the Bible pays a huge amount of attention to matters of reproduction: think of all the "begats", not to mention the virgin birth of Jesus. Jones takes this as a pretext to launch into a discussion of reproductive biology that wanders from sea urchin embryology and why there are two sexes, to sperm donation and genetic imprinting. By the time we get to the end of the chapter, we have strayed a long way from any remotely biblical topic.

Much of the book is like this – a collection of random walks from biblical starting points – and it leaves the reader feeling rather adrift. That is a shame, because, paragraph by paragraph, Jones is always lively and often wickedly funny. He notes, for example, that vicars and insurance sellers are in the same game – of convincing people to forgo immediate pleasures for long-term security.

To those who believe that humans are endowed with a soul from the moment of conception, he points out that his mother was an identical twin formed when a fertilised egg accidentally split into two separate embryos. What happened to the single soul when it found itself with two bodies? "Were my mother and her sister, my Aunt Pegi, blessed with just half a copy each," he asks, "or does God have a stock of spares ready to insert when needed?" Whatever the book's other faults, Jones is never boring.

But he can be hasty and careless. At one point he says that the pre-Columbian New World was sparsely populated by small, scattered bands; five pages on he says that large parts of South America were heavily settled and "buzzed with activity". Elsewhere, he writes that HIV is an exclusively human virus, but four pages later that it also infects chimps. Then there are the many unclear pronouns that sometimes leave us unsure as to the precise meaning of sentences. For example, when Jones writes about the first multi-drug-resistant plasmid – a transmissible ring of DNA – emerging in a strain of plague in Madagascar, he muddies the water with unclear uses of "it". If this book passed through an editor's hands, he or she left few prints. In a perfect world, authors would be perfect, but in the real world, we need editors to pick up the errors.

A bigger problem, though, is that Jones seems unclear who his audience is. He oversimplifies some concepts and goes into dizzying detail on others. The book skims too lightly over the surface to interest most science enthusiasts, and religious readers are likely to be put off by the barbed comments.

Read more at New Scientist

World's Smallest Liquid Droplets Ever Made in the Lab, Experiment Suggests

Physicists may have created the smallest drops of liquid ever made in the lab.

That possibility has been raised by the results of a recent experiment conducted by Vanderbilt physicist Julia Velkovska and her colleagues at the Large Hadron Collider, the world's largest and most powerful particle collider located at the European Laboratory for Nuclear and Particle Physics (CERN) in Switzerland. Evidence of the minuscule droplets was extracted from the results of colliding protons with lead ions at velocities approaching the speed of light.

According to the scientists' calculations, these short-lived droplets are the size of three to five protons. To provide a sense of scale, that is about one-100,000th the size of a hydrogen atom or one-100,000,000th the size of a virus.

"With this discovery, we seem to be seeing the very origin of collective behavior," said Velkovska, professor of physics at Vanderbilt who serves as a co-convener of the heavy ion program of the CMS detector, the LHC instrument that made the unexpected discovery. "Regardless of the material that we are using, collisions have to be violent enough to produce about 50 sub-atomic particles before we begin to see collective, flow-like behavior."

These tiny droplets "flow" in a manner similar to the behavior of the quark-gluon plasma, a state of matter that is a mixture of the sub-atomic particles that makes up protons and neutrons and only exists at extreme temperatures and densities. Cosmologists propose that the entire universe once consisted of this strongly interacting elixir for fractions of a second after the Big Bang when conditions were dramatically hotter and denser than they are today. Now that the universe has spent billions of years expanding and cooling, the only way scientists can reproduce this primordial plasma is to bang atomic nuclei together with tremendous energy.

The new observations are contained in a paper submitted by the CMS collaboration to the journal Physical Review D and posted on the arXiv preprint server. In addition, Vanderbilt doctoral student Shengquan Tuo recently presented the new results at a workshop held in the European Centre for Theoretical Studies in Nuclear Physics and Related Areas in Trento, Italy.

Scientists have been trying to recreate the quark-gluon plasma since the early 2000s by colliding gold nuclei using the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. This exotic state of matter is created when nuclei collide and dump a fraction of their energy into the space between them. When enough energy is released, it causes some of the quarks and gluons in the colliding particles to melt together to form the plasma. The RHIC scientists had expected the plasma to behave like a gas, but were surprised to discover that it acts like a liquid instead.

When the LHC started up, the scientists moved to the more powerful machine where they basically duplicated the results they got at RHIC by colliding lead nuclei.

In what was supposed to be a control run to check the validity of their lead-lead results, the scientists scheduled the collider to smash protons and lead nuclei together. They didn't expect to see any evidence of the plasma. Because the protons are so much lighter than lead nuclei (they have only one-208th the mass), it was generally agreed that proton-lead collisions couldn't release enough energy to produce the rare state of matter.

"The proton-lead collisions are something like shooting a bullet through an apple while lead-lead collisions are more like smashing two apples together: A lot more energy is released in the latter," said Velkovska.

Last September, the LHC did a brief test run to make sure it was adjusted properly to handle proton-lead collisions. When the results of the run were analyzed, team members were surprised to see evidence of collective behavior in five percent of the collisions -- those that were the most violent. In these cases, it appeared that when the "bullet" passed through "apple" it released enough energy to melt some of the particles surrounding the bullet hole. They appeared to be forming liquid droplets about one tenth the size of those produced by the lead-lead or gold-gold collisions.

However, the initial analysis was limited to tracking the motion of pairs of particles. The researchers knew that this analysis could be influenced by another well-known phenomenon, the production of particle jets. So, when the scheduled proton-lead run took place in January and February, they searched the data for evidence of groups of four particles that exhibit collective motion. After analyzing several billion events, they found hundreds of cases where the collisions produced more than 300 particles flowing together.

Read more at Science Daily

First Ever Underwater University Lectures

Students at the University of Essex have taken their lectures to a whole new level -- 18 metres under the sea in remote Indonesia to be precise.

The ground-breaking underwater marine biology lectures were the first of their kind, adding to the teaching, educational and learning experience during dives on tropical coral reef systems.

The lectures were held during the annual field trip to the Wakatobi Marine National Park in Indonesia, organised by the University's School of Biological Sciences for its students.

The serious challenges threatening the future of the world's coral reefs are the backbone of major research being carried out by the University's internationally-recognised Coral Reef Research Unit (CRRU). Its on-going research, focused in this area of Indonesia, looks at the impact of climate change on coral reefs and how to work with nature to find a solution. More than half a billion people depend on coral reefs for food and income.

For the underwater lectures, Professor David Smith used specialised audio equipment so he could talk to students underwater, explaining exactly what they were seeing as they were seeing it. This was a world away from usual underwater communication involving basic slates to write on and hand signals.

"It was a fantastic experience as I was able to use the power of observation like never before," explained Professor Smith. "I have been on thousands of dives over the years but this was a totally new experience as I was able to explain to students exactly what they were seeing and inject more passion and feeling into the whole lecture. It was very special and transformed the whole experience both for me and our students."

Using a University of Essex special teaching grant, Professor Smith was able to buy an audio system which, to date, has never been used for formal lecturing and is only used by TV presenters and some professional divers. Professor Smith wore a full face mask which included a microphone and the students wore headsets so they could hear him talk. A hydrophone -- an underwater microphone − was then positioned in the water which was linked to a control box and recorder on a boat.

With over 1,000 videos taken during the underwater lectures, adding up to 15 hours of footage, these will prove to be a valuable virtual field course resource for students who are not able to travel to Indonesia but can still get an insight into the experience whilst also providing a great "listen again" opportunity for participating students.

Second-year marine and freshwater biology student Tilly James said: "The underwater lectures were an invaluable part of the course as they enabled us to get a much better understanding of how all the components of the reef system were interacting with each other.

Read more at Science Daily