Jan 3, 2015

Quantum channel made of light

Two vessels filled with gas and connected by a channel -- this is the basic setting for the experiments carried out by the physicists at the ETH Institute for Quantum Electronics. As one vessel contains more gas than the other, particles flow through the channel from one side to the other. "The question now is how the conductivity changes as we gradually make the channel narrower," says physics professor Tilman Esslinger. Initially, the conductivity decreases smoothly. However, at some point an amazing phenomenon appears: the conductivity does not change continuously anymore, but in steps, and the size of the steps is determined by a fundamental entity known as the Planck constant. "This is an immediate consequence of quantum physics," explains Esslinger.

The phenomenon has been observed before, but only in electronic systems, such as in quantum point contacts in specific semiconductor structures. "We have now observed for the first time quantisation of conductivity in neutral matter; that is, for particles that are not charged," says Esslinger. "This experiment is certainly something for the quantum-physics textbooks."

This basic-research project, which is supported by the Swiss National Science Foundation (SNF) and the European Union, might be of relevance for the design and construction of the next generation of electronic devices, as it enables the future study of effects that currently cannot be explored with electronic systems.

Cooling to almost absolute zero

The group led by Tilman Esslinger works with ultracold atoms. In the experiment described by the researchers in the current issue of the journal Nature, they used a gas consisting of lithium atoms at a temperature of merely 35 billionths of a degree above absolute zero. "Cooling is the main focus of our work in the lab," says Dr Jean-Philippe Brantut, SNF Ambizione Fellow at the Institute for Quantum Electronics. "99 percent of our equipment, which we developed in house, serves that purpose." Cooled to such low temperatures, the lithium atoms behave similarly to electrons in a solid-state material, even if -- in contrast to electrons -- the atoms are not charged.

The centrepieces of the complex experimental setup are a high-vacuum glass cell and two ultra-high-resolution microscopes. The lithium gas sits in the cell between the microscopes, in a cigar-shaped cloud with a diameter of approximately 300 micrometres. A laser beam divides this cloud into two reservoirs, connected by a narrow two-dimensional channel. A second laser beam passes through a lithographically produced mask and then through a projection system made of a lens and one of the microscopes. In this way, the pattern defined on the mask is reduced to the size of the channel. As a result, a quantum point contact with a width of just one micrometre is created, as can be validated using the other microscope.

Microscopic flow requires a stable system

The channel structure is sufficiently narrow that the laws of quantum mechanics come into play. This means that for atoms flowing through the channel, the conductivity should change not continuously but in steps, whose size are given by Planck's quantum of action, which is a fundamental constant of nature. This behaviour is precisely what the research group has observed. Ten atoms are in the channel at a time, says Brantut. To make the microscopic flow visible, the channel had to be kept open until 1,000 or so atoms have passed through it. This took some 1.5 seconds, which is a rather long time for an experiment of this type. "The experiment can only work if the atoms are very stable -- that is, extremely cold -- and nothing else changes," explains the physicist.

Read more at Science Daily

NASA's Mercury Spacecraft Gets a Life 'Boost'

Engineers have figured out a way to buy some time for NASA’s Mercury-orbiting MESSENGER spacecraft, which was due to end its four-year mission with a suicidal plunge into the innermost planet in March.

Launched in 2004, MESSENGER — an acronym for Mercury Surface, Space Environment, Geochemistry and Ranging — is about out of hydrazine fuel for its steering thrusters. The spacecraft became the first to put itself into orbit around Mercury in March 2011.

It’s already flying quite low. Engineers estimate its altitude will be just 15 miles above the surface on Jan 21. But on that day, despite its empty gas tan, MESSENGER will attempt a reboost. Engineers instead devised a maneuver using leftover helium from the system that keeps the propulsion system pressurized.

“To my knowledge this is the first time that helium pressurant has been intentionally used as a cold-gas propellant through hydrazine thrusters,” MESSENGER lead propulsion engineer Stewart Bushman, with Johns Hopkins University Applied Research Laboratory, said in a statement.

With its low mass, helium “doesn’t get you much bang for your buck,” he added.

But the boost should buy scientists about another month of time to learn about variations in Mercury’s internal magnetic field and study water ice inside craters in the planet’s northern latitudes.

From Discovery News

Jan 2, 2015

NASA finds good news on forests and carbon dioxide

A new NASA-led study shows that tropical forests may be absorbing far more carbon dioxide than many scientists thought, in response to rising atmospheric levels of the greenhouse gas. The study estimates that tropical forests absorb 1.4 billion metric tons of carbon dioxide out of a total global absorption of 2.5 billion -- more than is absorbed by forests in Canada, Siberia and other northern regions, called boreal forests.

"This is good news, because uptake in boreal forests is already slowing, while tropical forests may continue to take up carbon for many years," said David Schimel of NASA's Jet Propulsion Laboratory, Pasadena, California. Schimel is lead author of a paper on the new research, appearing online in the Proceedings of National Academy of Sciences.

Forests and other land vegetation currently remove up to 30 percent of human carbon dioxide emissions from the atmosphere during photosynthesis. If the rate of absorption were to slow down, the rate of global warming would speed up in return.

The new study is the first to devise a way to make apples-to-apples comparisons of carbon dioxide estimates from many sources at different scales: computer models of ecosystem processes, atmospheric models run backward in time to deduce the sources of today's concentrations (called inverse models), satellite images, data from experimental forest plots and more. The researchers reconciled all types of analyses and assessed the accuracy of the results based on how well they reproduced independent, ground-based measurements. They obtained their new estimate of the tropical carbon absorption from the models they determined to be the most trusted and verified.

"Until our analysis, no one had successfully completed a global reconciliation of information about carbon dioxide effects from the atmospheric, forestry and modeling communities," said co-author Joshua Fisher of JPL. "It is incredible that all these different types of independent data sources start to converge on an answer."

The question of which type of forest is the bigger carbon absorber "is not just an accounting curiosity," said co-author Britton Stephens of the National Center for Atmospheric Research, Boulder, Colorado. "It has big implications for our understanding of whether global terrestrial ecosystems might continue to offset our carbon dioxide emissions or might begin to exacerbate climate change."

As human-caused emissions add more carbon dioxide to the atmosphere, forests worldwide are using it to grow faster, reducing the amount that stays airborne. This effect is called carbon fertilization. "All else being equal, the effect is stronger at higher temperatures, meaning it will be higher in the tropics than in the boreal forests," Schimel said.

But climate change also decreases water availability in some regions and makes Earth warmer, leading to more frequent and larger wildfires. In the tropics, humans compound the problem by burning wood during deforestation. Fires don't just stop carbon absorption by killing trees, they also spew huge amounts of carbon into the atmosphere as the wood burns.

For about 25 years, most computer climate models have been showing that mid-latitude forests in the Northern Hemisphere absorb more carbon than tropical forests. That result was initially based on the then-current understanding of global air flows and limited data suggesting that deforestation was causing tropical forests to release more carbon dioxide than they were absorbing.

In the mid-2000s, Stephens used measurements of carbon dioxide made from aircraft to show that many climate models were not correctly representing flows of carbon above ground level. Models that matched the aircraft measurements better showed more carbon absorption in the tropical forests. However, there were still not enough global data sets to validate the idea of a large tropical-forest absorption. Schimel said that their new study took advantage of a great deal of work other scientists have done since Stephens' paper to pull together national and regional data of various kinds into robust, global data sets.

Schimel noted that their paper reconciles results at every scale from the pores of a single leaf, where photosynthesis takes place, to the whole Earth, as air moves carbon dioxide around the globe. "What we've had up till this paper was a theory of carbon dioxide fertilization based on phenomena at the microscopic scale and observations at the global scale that appeared to contradict those phenomena. Here, at least, is a hypothesis that provides a consistent explanation that includes both how we know photosynthesis works and what's happening at the planetary scale."

Read more at Science Daily

Defying textbook science, study finds new role for proteins

Open any introductory biology textbook and one of the first things you'll learn is that our DNA spells out the instructions for making proteins, tiny machines that do much of the work in our body's cells. Results from a study published on Jan. 2 in Science defy textbook science, showing for the first time that the building blocks of a protein, called amino acids, can be assembled without blueprints -- DNA and an intermediate template called messenger RNA (mRNA). A team of researchers has observed a case in which another protein specifies which amino acids are added.

"This surprising discovery reflects how incomplete our understanding of biology is," says first author Peter Shen, Ph.D., a postdoctoral fellow in biochemistry at the University of Utah. "Nature is capable of more than we realize."

To put the new finding into perspective, it might help to think of the cell as a well-run factory. Ribosomes are machines on a protein assembly line, linking together amino acids in an order specified by the genetic code. When something goes wrong, the ribosome can stall, and a quality control crew is summoned to the site. To clean up the mess, the ribosome is disassembled, the blueprint is discarded, and the partly made protein is recycled.

Yet this study reveals a surprising role for one member of the quality control team, a protein conserved from yeast to man named Rqc2. Before the incomplete protein is recycled, Rqc2 prompts the ribosomes to add just two amino acids (of 20 total) -- alanine and threonine -- over and over, and in any order. Think of an auto assembly line that keeps going despite having lost its instructions. It picks up what it can and slaps it on: horn-wheel-wheel-horn-wheel-wheel-wheel-wheel-horn.

"In this case, we have a protein, Rqc2, playing a role similar to that of mRNA," says Adam Frost, M.D., Ph.D., assistant professor at University of California, San Francisco (UCSF) and adjunct professor of biochemistry at the University of Utah. He shares senior authorship with Jonathan Weissman, Ph.D., a Howard Hughes Medical Institute investigator at UCSF, and Onn Brandman, Ph.D., at Stanford University. "I love this story because it blurs the lines of what we thought proteins could do."

Like a half-made car with extra horns and wheels tacked to one end, a truncated protein with an apparently random sequence of alanines and threonines looks strange, and probably doesn't work normally. But the nonsensical sequence likely serves specific purposes. The code could signal that the partial protein must be destroyed, or it could be part of a test to see whether the ribosome is working properly. Evidence suggests that either or both of these processes could be faulty in neurodegenerative diseases such as Alzheimer's, Amyotrophic lateral sclerosis (ALS), or Huntington's.

"There are many interesting implications of this work and none of them would have been possible if we didn't follow our curiosity," says Brandman. "The primary driver of discovery has been exploring what you see, and that's what we did. There will never be a substitute for that."

The scientists first considered the unusual phenomenon when they saw evidence of it with their own eyes. They fine-tuned a technique called cryo-electron microscopy to flash freeze, and then visualize, the quality control machinery in action. "We caught Rqc2 in the act," says Frost. "But the idea was so far-fetched. The onus was on us to prove it."

Read more at Science Daily

Dec 31, 2014

Happy New Year

The year has come to an end. They tend to do so.

Here at A Magical Journey I want to take the time to reflect on the year that passed and on the new year that is about to begin.
There will allways be advancements in Science and there's allways time to read about them. Don't be that fool that says that science is allways wrong. Read about science and read articles about the things that you might be intrested in. It might surprise you. It might even teach you something.

With that said I want to wish everybody in the world a Happy New Year!

Here's a little song for you all!

Danny Boston from A Magical Journey

Dec 30, 2014

Children with autism who live with pets are more assertive

Dogs and other pets play an important role in individuals' social lives, and they can act as catalysts for social interaction, previous research has shown. Although much media attention has focused on how dogs can improve the social skills of children with autism, a University of Missouri researcher recently found that children with autism have stronger social skills when any kind of pet lived in the home.

"When I compared the social skills of children with autism who lived with dogs to those who did not, the children with dogs appeared to have greater social skills," said Gretchen Carlisle, research fellow at the Research Center for Human-Animal Interaction (ReCHAI) in the MU College of Veterinary Medicine. "More significantly, however, the data revealed that children with any kind of pet in the home reported being more likely to engage in behaviors such as introducing themselves, asking for information or responding to other people's questions. These kinds of social skills typically are difficult for kids with autism, but this study showed children's assertiveness was greater if they lived with a pet."

Pets often serve as "social lubricants," Carlisle said. When pets are present in social settings or a classroom, children talk and engage more with one another. This effect also seems to apply to children with autism and could account for their increased assertiveness when the children are living in a home with pets, Carlisle said.

"When children with disabilities take their service dogs out in public, other kids stop and engage," Carlisle said. "Kids with autism don't always readily engage with others, but if there's a pet in the home that the child is bonded with and a visitor starts asking about the pet, the child may be more likely to respond."

Carlisle also found that children's social skills increased the longer a family had owned a dog, yet older children rated their relationships with their dogs as weaker. When children were asked, they reported the strongest attachments to smaller dogs, Carlisle found.

"Finding children with autism to be more strongly bonded to smaller dogs, and parents reporting strong attachments between their children and other pets, such as rabbits or cats, serves as evidence that other types of pets could benefit children with autism as well," Carlisle said.

Carlisle surveyed 70 families who had children with autism between the ages of 8 and 18.The children were patients at the MU Thompson Center for Autism and Neurodevelopmental Disorders. Almost 70 percent of the families that participated had dogs, and about half of the families had cats. Other pets owned by participants included fish, farm animals, rodents, rabbits, reptiles, a bird and even one spider.

Read more at Science Daily

Gift-wrapped gas molecules

A group of scientists led by researchers at the Université de Versailles' Institut Lavoisier in France has worked out how to stably gift-wrap a chemical gas known as nitric oxide within metal-organic frameworks. Such an encapsulated chemical may allow doctors to administer nitric oxide in a more highly controlled way to patients, suggesting new approaches for treating dangerous infections and heart conditions with the biologically-active substance.

Not to be confused with the chemically-distinct anesthetic dentists use -- its cousin nitrous oxide (NO2), also known as laughing gas -- nitric oxide (NO) is one of very few gas molecules known to be involved in biological signaling pathways, the physiological gears that make the body tick at the microscopic level. It is very active biologically and can be found in bacteria, plant, animal and fungi cells.

In humans, NO is a powerful vasodilator, increasing blood flow and lowering vascular pressure. For this reason, gaseous NO is sometimes used to treat respiratory failure in premature infants. It also has strong antibacterial potency, owing to its molecular action as a biologically disruptive free radical, and cells in the human immune system naturally produce NO as a way of killing pathogenic invaders. Additionally, nitric oxide is believed to be the main vasoactive neurotransmitter regulating male erection, as aging nerves with reduced stimulation can inhibit the release of the molecule, thus causing erectile dysfunction. This, of course, can be mediated by taking nitric oxide supplements to achieve an erection.

While such activity would seem to make NO a prime candidate for drug design, the problem is delivery -- because it is a gas. In recent years, the gas storage capacity and biocompatibility of metal-organic-frameworks -- dissolvable compounds consisting of metal ions and rigid organic chemicals that can stably trap gas molecules -- have gained significant attention as candidates for delivering gas-based drugs. The new work extends this further than ever before, showing that these metal-organic frameworks can store and slowly deliver NO over an unprecedented amount of time, which is key for the drug's anti-thrombogenic action.

"This is an elegant and efficient method to store and deliver large amounts of NO for antibacterial purposes," said Christian Serre. "Or it can release controlled amounts of nitric oxide at the very low biological level for a prolonged period of time, in order to use it as a way to inhibit platelet aggregation." Serre is a CNRS research director at the Institut Lavoisier de Versailles, and also heads the institute's 'Porous Solids' research group.

Serre's consortium has previously reported the use of porous hybrid solids, such as metal-organic-frameworks, for the controlled delivery of nitric oxide gas. Their current paper on derivatives of iron polycarboxylates as framework candidate appears in the journal APL Materials, from AIP Publishing.

Serre and his group worked in collaboration with Russell Morris's team at the University of St Andrews in Scotland and researchers from Université de Basse-Normandie in France. The groups analyzed the NO adsorption and release properties of several porous biodegradable and biocompatible iron carboxylate metal-organic frameworks by use of infrared spectroscopy analysis, adsorption & desorption isotherms and water-triggered release tests.

Read more at Science Daily

Belize's 'Blue Hole' Reveals Clues to Maya's Demise

The ancient Mayan civilization collapsed due to a century-long drought, new research suggests.

Minerals taken from Belize's famous underwater cave, known as the Blue Hole, as well as lagoons nearby, show that an extreme drought occurred between A.D. 800 and A.D. 900, right when the Mayan civilization disintegrated. After the rains returned, the Mayans moved north — but they disappeared again a few centuries later, and that disappearance occurred at the same time as another dry spell, the sediments reveal.

Although the findings aren't the first to tie a drought to the Mayan culture's demise, the new results strengthen the case that dry periods were indeed the culprit. That's because the data come from several spots in a region central to the Mayan heartland, said study co-author André Droxler, an Earth scientist at Rice University.

Rise and decline

From A.D. 300 to A.D. 700, the Mayan civilization flourished in the Yucatan peninsula. These ancient Mesoamericans built stunning pyramids, mastered astronomy, and developed both a hieroglyphic writing system and a calendar system, which is famous for allegedly predicting that the world would end in 2012.

But in the centuries after A.D. 700, the civilization's building activities slowed and the culture descended into warfare and anarchy. Historians have speculatively linked that decline with everything from the ancient society's fear of malevolent spirits to deforestation completed to make way for cropland to the loss of favored foods, such as the Tikal deer.

The evidence for a drought has been growing in recent years: Since at least 1995, scientists have been looking more closely at the effects of drought. A 2012 study in the journal Science analyzed a 2,000-year-old stalagmite from a cave in southern Belize and found that sharp decreases in rainfall coincided with periods of decline in the culture. But that data came from just one cave, which meant it was difficult to make predictions for the area as a whole, Droxler said.

The main driver of this drought is thought to have been a shift in the intertropical convergence zone (ITCZ), a weather system that generally dumps water on tropical regions of the world while drying out the subtropics. During summers, the ITCZ pelts the Yucatan peninsula with rain, but the system travels farther south in the winter. Many scientists have suggested that during the Mayan decline, this monsoon system may have missed the Yucatan peninsula altogether.

Deep history

To look for signs of drought, the team drilled cores from the sediments in the Blue Hole of Lighthouse lagoon, as well one in the Rhomboid reef. The lagoons surrounded on all sides by thick walls of coral reef.

During storms or wetter periods, excess water runs off from rivers and streams, overtops the retaining walls, and is deposited in a thin layer at the top of the lagoon. From there, all the sediments from these streams settle to the bottom of the lagoon, piling on top of each other and leaving a chronological record of the historical climate.

"It's like a big bucket. It's a sediment trap," Droxler told Live Science.

Droxler and his colleagues analyzed the chemical composition of the cores, in particular the ratio of titanium to aluminum. When the rains fall, it eats away at the volcanic rocks of the region, which contain titanium. The free titanium then sweeps into streams that reach the ocean. So relatively low ratios of titanium to aluminum correspond to periods with less rainfall, Droxler said.

The team found that during the period between A.D. 800 and A.D. 1000, when the Maya civilization collapsed, there were just one or two tropical cyclones every two decades, as opposed to the usual five or six. After that, the Maya moved north, building at sites such as Chichen Itza, in what is now Mexico.

But the new results also found that between A.D. 1000 and A.D. 1100, during the height of the Little Ice Age, another major drought struck. This period coincides with the fall of Chichen Itza.

Read more at Discovery News

Venus May Have Once Been Awash With CO2 Oceans

Venus may have once possessed strange oceans of carbon dioxide fluid that helped shape the planet's surface, researchers say.

Venus is often described as Earth's twin planet because it is the world closest to Earth in size, mass, distance and chemical makeup. However, whereas Earth is a haven for life, Venusis typically described as hellish, with a crushing atmosphere and clouds of corrosive sulfuric acid floating over a rocky desert surface hot enough to melt lead.

Although Venus is currently unbearably hot and dry, it might have once had oceans like Earth. Prior research suggested that Venus possessed enough water in its atmosphere in the past to cover the entire planet in an ocean about 80 feet deep (25 meters) — if all that water could somehow fall down as rain. But the planet was probably too warm for such water to cool down and precipitate, even if the planet did have enough moisture.

Instead of seas of water, then, scientists now suggest that Venus might have once possessed bizarre oceans of carbon dioxide fluid.

Carbon dioxide is common on Venus.

"Presently, the atmosphere of Venus is mostly carbon dioxide, 96.5 percent by volume," said lead study author Dima Bolmatov, a theoretical physicist at Cornell University in Ithaca, New York.

Most familiar on Earth as a greenhouse gas that traps heat, helping warm the planet, carbon dioxide is exhaled by animals and used by plants in photosynthesis. While the substance can exist as a solid, liquid and gas, past a critical point of combined temperature and pressure, carbon dioxide can enter a "supercritical" state. Such a supercritical fluid can have properties of both liquids and gases. For example, it can dissolve materials like a liquid, but flow like a gas.

To see what the effects of supercritical carbon dioxideon Venus might be, Bolmatov and his colleagues investigated the unusual properties of supercritical matter. A great deal remains uncertain about such substances, he said.

Scientists had generally thought the physical properties of supercritical fluids changed gradually with pressure and temperature. However, in computer simulations of molecular activity, Bolmatov and his colleagues found that supercritical matter could shift dramatically from gaslike to liquidlike properties.

The atmospheric pressure on the surface of Venus is currently more than 90 times that of Earth, but in the early days of the planet, Venus' surface pressure could have been dozens of times greater. This could have lasted over a relatively long time period of 100 million to 200 million years. Under such conditions, supercritical carbon dioxide with liquidlike behavior might have formed, Bolmatov said.

"This in turn makes it plausible that geological features on Venus like rift valleys, riverlike beds, and plains are the fingerprints of near-surface activity of liquidlike supercritical carbon dioxide," Bolmatov told Space.com.

Read more at Discovery News

Dec 29, 2014

2014 Skeptical Award

This years Skeptical Award has been as avery other year, a long process. Usually I start to look for candidates in the early spring and this year was no exception.

What I look for in a winner of the Skeptical Award is that they can prove themself to be true to science, true to Skeptical thinking and being able to change their mind if proven wrong. This is why no woowoos will ever win the skeptical award!

This year I have choosen an author for the skeptical award. The reason I have choosen this person is as follows:

Throughout the year, this person has been fighting religios dogma in a way that hasn't changed througout the year and is fighting for the facts that is out there. He's been writing books (Yes it's a he), writing on twitter, writing on facebook and alot of other places to make a point.
He doesn't win any money (Cuase I don't have any to give him (Unemplyed)) but he wins respect from the people who reads this blog and he has won alot of respect from me throughout the year!

This years winner of The Skeptical Award is: Michael Sherlock!

Here is where you can find him:

Twitter: https://twitter.com/sherlockmichael

Facebook https://t.co/Yo71QyOtEq

Website: http://humanrightsforaas.org/

You can find his books on Amazoon.com http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=Michael+Sherlok

Congratulations Michael for the award!

Yours truly
Danny Boston @ A Magical Journey

Chinese Civilization's Mysterious Disappearance Solved

An earthquake nearly 3,000 years ago may be the culprit in the mysterious disappearance of one of China's ancient civilizations, new research suggests.

The massive temblor may have caused catastrophic landslides, damming up the Sanxingdui culture's main water source and diverting it to a new location.

That, in turn, may have spurred the ancient Chinese culture to move closer to the new river flow, study co-author Niannian Fan, a river sciences researcher at Tsinghua University in Chengdu, China, said Dec. 18 at the 47th annual meeting of the American Geophysical Union in San Francisco.

In 1929, a peasant in Sichuan province uncovered jade and stone artifacts while repairing a sewage ditch located about 24 miles (40 kilometers) from Chengdu. But their significance wasn't understood until 1986, when archaeologists unearthed two pits of Bronze Age treasures, such as jades, about 100 elephant tusks and stunning 8-feet-high (2.4 meters) bronze sculptures that suggest an impressive technical ability that was present nowhere else in the world at the time, said Peter Keller, a geologist and president of the Bowers Museum in Santa Ana, California, which is currently hosting an exhibit of some of these treasures.

The treasures, which had been broken and buried as if they were sacrificed, came from a lost civilization, now known as the Sanxingdui, a walled city on the banks of the Minjiang River.

"It's a big mystery," said Keller, who was not involved in the current study.

Archaeologists now believe that the culture willfully dismantled itself sometime between 3,000 and 2,800 years ago, Fan said.

"The current explanations for why it disappeared are war and flood, but both are not very convincing," Fan told Live Science.

But about 14 years ago, archaeologists found the remains of another ancient city called Jinsha near Chengdu. The Jinsha site, though it contained none of the impressive bronzes of Sanxingdui, did have a gold crown with a similar engraved motif of fish, arrows and birds as a golden staff found at Sanxingdui, Keller said. That has led some scholars to believe that the people from Sanxingdui may have relocated to Jinsha.

But why has remained a mystery.

Fan and his colleagues wondered whether an earthquake may have caused landslides that dammed the river high up in the mountains and rerouted it to Jinsha. That catastrophe may have reduced Sanxingdui's water supply, spurring its inhabitants to move.

The valley where Sanxingdui sits has a large floodplain, with 4.3 miles (7 kilometers) of high terraced walls that were unlikely to have been cut by the small river that now flows through it, Fan said.

And some historical records support their hypothesis. In 1099 B.C., ancient writers recorded an earthquake in the capital of the Zhou dynasty, in Shaanxi province, Fan said. Though that spot is roughly 250 miles (400 kilometers) from the historic site of Sanxingdui, the latter culture didn't have writing at the time, so it's possible the earthquake epicenter was actually close to Sanxingdui — but it just wasn't recorded there, Fan said. Geological evidence also suggests that an earthquake occurred in the general region between 3,330 and 2,200 years ago, he added.

Around the same time, geological sediments suggest massive flooding occurred, and the later-Han dynasty document "The Chronicles of the Kings of Shu" records ancient floods pouring from a mountain in a spot that suggests the flow being rerouted, Fan said. (Around 800 years later, Jinsha residents built a wall to prevent flooding.)

Together, the findings hint that a major earthquake triggered a landslide that dammed the river, rerouting its flow and reducing water flow to Sanxingdui, Fan said.

But if so, where did the river get rerouted? The team found clues high up in the mountains in the deep and wide Yanmen Ravine, at about 12,460 feet (3,800 meters) above sea level.

The modern-day river cuts through the ravine, which was carved by glaciers about 12,000 years ago. Yet the telltale signs of that glacial erosion — bowl-shaped basins known as cirques — are mysteriously absent for a long stretch of the ravine. The team hypothesizes that an earthquake spurred an avalanche that then wiped out some of the cirques about 3,000 years ago.

Read more at Discovery News

Mars Orbiter Spies Alien Ice 'Spiders'

The Martian surface is covered with a diverse array of landscapes and features, but this is one of the weirdest.

Imaged by the High-Resolution Imaging Science Experiment (HiRISE) camera on board NASA’s Mars Reconnaissance Orbiter (MRO) that orbits the planet 150 miles overhead, strange spider-like formations cover this south polar region of Mars. And these are truly alien features that are found nowhere on Earth.

So what are they? Is Mars infested with arachnids? Or is it some sort of giant mold? Sadly, it’s neither, it’s actually a fascinating season-driven phenomena that HiRISE scientists call “araneiform” terrain.

Araneiform means, perhaps unsurprisingly, “spider-like” and the term applies to other features that have a “spider”, “caterpillar” or “starburst”-like shape, according to planetary scientist Candice Hansen who described the same south pole region in an earlier HiRISE image release.

The Martian climate is so cold that even carbon dioxide will freeze from the atmosphere and accumulate as ice on the surface during winter. During spring, the carbon dioxide will sublimate back into the atmosphere as it is heated by a strengthening sun.

Carbon dioxide ice on Mars does not melt into a liquid state; it bypasses the liquid phase and sublimates straight from a solid into a vapor. This seasonal process therefore creates its own type of erosion on the Martian landscape.

“This particular example shows eroded channels filled with bright ice, in contrast to the muted red of the underlying ground,” writes Hansen. “In the summer the ice will disappear into the atmosphere, and we will see just the channels of ghostly spiders carved in the surface.”

Earth’s atmospheric temperature does not drop as low as Mars’, so carbon dioxide ice (or “dry ice”) does not form naturally. Therefore, there is no terrestrial analog of these alien spider channels — it is purely a Mars phenomenon.

Read more at Discovery News

Unexplained Mysteries of 2014 and Into 2015

As we head toward 2015, look back at some of the strangest mysteries of this past year, as well as some of the mysteries that remain as we enter the new year.

Keeping in mind that science is a process of continually refining a body of scientific knowledge -- that what we believe is true today may be changed by some amazing new discovery tomorrow -- here are 10 strange mysteries, both unexplained and recently explained.

For almost a century one of America's strangest mysteries has been found in remote Death Valley, California. It's there -- actually at a specific dry lakebed called Racetrack Playa -- that stones are claimed to mysteriously move on their own, when no one is looking. The phenomenon occurs in a handful of other places as well, though none are as well known as those in Death Valley. They moved very slowly, in some cases only a few inches over months or years, but their trails can clearly be seen in the dried mud behind them.

Over the years many explanations have been offered, ranging from hoaxing to aliens to some sort of localized, unknown magnetic effect.

Others have suggested that the area's strong winds might move the stones, but that doesn't explain why they'd move at different rates and sometimes in different directions. For many years the best scientific explanation was that the rocks moved due to a specific combination of wind, temperature, and water. Racetrack Playa is in a desert, but sometimes collects water from rain and melting snow, providing a slick surface over which the stones might move.

The mystery was finally solved in 2014 when a team of researchers set up cameras over the area and measured the rocks' movement patterns. They concluded that the stones moved under just the right conditions when ice formed under the rocks and moved them, usually only a little bit at a time: "moving sheets of ice tens of meters in extent but only a few millimeters thick are clearly effective at moving rocks in their path." The study, "Sliding Rocks on Racetrack Playa, Death Valley National Park: First Observation of Rocks in Motion" was published on Aug. 27, 2014 in the open-access journal PLoS ONE.

Volcanoes are known around the world, though most of them can be found in the so-called Pacific Ring of Fire. It's where the world's most active volcanoes are located, covering the western edge of the Americas, Hawaii, Japan and into Oceania. The volcanoes there result from the subduction of oceanic tectonic plates moving beneath lighter continental plates.

Most of Australia, however, is spared -- except for an unusual 300-mile stretch in the southeastern part of the country roughly north of Tasmania. It is the continent's only active volcanic region, but for many years no one was quite sure why. Since Australia lies well inside its own tectonic plate (called the Indo-Australian plate), it could not be caused by the same geological processes that spawned others in the nearby Ring of Fire.

A team from the Research School of Earth Sciences finally solved the mystery earlier this year. According to lead researcher Dr. Rhodri Davies, "Volcanoes in this region of Australia are generated by a very different process to most of Earth's volcanoes.... We have determined that the volcanism arises from a unique interaction between local variations in the continent's thickness, which we were able to map for the first time, and its movement...towards New Guinea and Indonesia."

The continent's drift northward creates an isolated region in its southern end which spawned the volcano. But don't stand on Australia's northern shore expecting to reach Indonesia any time soon: the continent is moving northward at about two and three-quarter inches a year. The study was published in the journal "Geology" on Sept. 24.

Water on Mars

The riddle of Mars has captivated people for generations. Dozens of artists, writers, astronomers and dreamers -- from H.G. Wells to Orson Welles, Ray Bradbury to Carl Sagan -- have speculated about what life might be like on the Red Planet.

In 2011, NASA's Curiosity Rover was launched into space, landing on Mars the following year. Mankind's amazing little mechanical scientist trooper has spent the past few years poking, plodding and examining the surface. A lot has been learned about Martian climate and geology, but in 2014 the biggest news was that Curiosity gathered evidence that a peak there, known as Mount Sharp, was created by sediments in a huge surrounding lake bed.

Yes, sediments -- which if you remember high school geology, is particulate matter carried by water or wind (in this case water). And yes, lake bed: There's no water there now, at least not on the surface, but the discovery is very strong evidence that rivers and lakes have existed periodically in Martian history. Having spent a Martian year on the planet, scientists now believe that the environmental conditions on Mars may be favorable for microbial life, and the search continues.

Missing Stars

If you're lucky enough to get away from urban light pollution and into rural areas, it's astonishing how many stars you can see; they seem to litter the sky. And, of course, only a small fraction of the stars are visible to our naked eye. But even still, there should be more of them -- many more.

One of the most enduring astronomical puzzles has been not why there are so many stars, but instead so few. According to computer models there should be an estimated 100 to 300 sextillion stars, or 100,000,000,000,000,000,000,000 to 300,000,000,000,000,000,000,000, give or take a few. It's a number so large that it defies comprehension and raises an interesting question: where are they? Why isn't the night sky positively lit up with stars? Surely the light from a small number of them (say, maybe a few hundred million or so) might be blocked from reaching us by planets or other celestial objects, but that still leaves some ridiculously large number of stars unaccounted for.

Earlier this year astronomer James Geach and his team at the University of Hertsfordshire found that "nuclear bursts of star formation are capable of ejecting large amounts of cold gas from the central regions of galaxies, thereby strongly affecting their evolution by truncating star formation and redistributing matter." In other words, the cold gases used as the raw material for stars -- and driven out during the star formation process itself -- can inhibit the creation of new stars. The article, "Stellar feedback as the origin of an extended molecular outflow in a starburst galaxy," was published in the Dec 4 issue of the journal Nature.

Read more at Discovery News

Dec 28, 2014

Modern genetics confirm ancient relationship between fins and hands

Paleontologists have documented the evolutionary adaptations necessary for ancient lobe-finned fish to transform pectoral fins used underwater into strong, bony structures, such as those of Tiktaalik roseae. This enabled these emerging tetrapods, animals with limbs, to crawl in shallow water or on land. But evolutionary biologists have wondered why the modern structure called the autopod--comprising wrists and fingers or ankles and toes--has no obvious morphological counterpart in the fins of living fishes.

In the Dec. 22, 2014, issue of the Proceedings of the National Academy of Sciences, researchers argue previous efforts to connect fin and fingers fell short because they focused on the wrong fish. Instead, they found the rudimentary genetic machinery for mammalian autopod assembly in a non-model fish, the spotted gar, whose genome was recently sequenced.

"Fossils show that the wrist and digits clearly have an aquatic origin," said Neil Shubin, PhD, the Robert R. Bensley Professor of organismal biology and anatomy at the University of Chicago and a leader of the team that discovered Tiktaalik in 2004. "But fins and limbs have different purposes. They have evolved in different directions since they diverged. We wanted to explore, and better understand, their connections by adding genetic and molecular data to what we already know from the fossil record."

Initial attempts to confirm the link based on shape comparisons of fin and limb bones were unsuccessful. The autopod differs from most fins. The wrist is composed of a series of small nodular bones, followed by longer thin bones that make up the digits. The bones of living fish fins look much different, with a set of longer bones ending in small circular bones called radials.

The primary genes that shape the bones, known as the HoxD and HoxA clusters, also differ. The researchers first tested the ability of genetic "switches" that control HoxD and HoxA genes from teleosts--bony, ray-finned fish--to shape the limbs of developing transgenic mice. The fish control switches, however, did not trigger any activity in the autopod.

Teleost fish--a vast group that includes almost all of the world's important sport and commercial fish--are widely studied. But the researchers began to realize they were not the ideal comparison for studies of how ancient genes were regulated. When they searched for wrist and digit-building genetic switches, they found "a lack of sequence conservation" in teleost species.

They traced the problem to a radical change in the genetics of teleost fish. More than 300 million years ago, after the fish-like creatures that would become tetrapods split off from other bony fish, a common ancestor of the teleost lineage went through a whole-genome duplication (WGD)--a phenomenon that has occurred multiple times in evolution.

By doubling the entire genetic repertoire of teleost fish, this WGD provided them with enormous diversification potential. This may have helped teleosts to adapt, over time, to a variety of environments worldwide. In the process, "the genetic switches that control autopod-building genes were able to drift and shuffle, allowing them to change some of their function, as well as making them harder to identify in comparisons to other animals, such as mice," said Andrew Gehrke, a graduate student in the Shubin lab and lead author of the study.

Not all bony fishes went through the whole genome duplication, however. The spotted gar, a primitive freshwater fish native to North America, split off from teleost fishes before the WGD.

When the research team compared Hox gene switches from the spotted gar with tetrapods, they found "an unprecedented and previously undescribed level of deep conservation of the vertebrate autopod regulatory apparatus." This suggests, they note, a high degree of similarity between "distal radials of bony fish and the autopod of tetrapods."

They tested this by inserting gar gene switches related to fin development into developing mice. This evoked patterns of activity that were "nearly indistinguishable," the authors note, from those driven by the mouse genome.

"Overall," the researchers conclude, "our results provide regulatory support for an ancient origin of the 'late' phase of Hox expression that is responsible for building the autopod."

Read more at Science Daily

Did Microbes Shape the Human Lifespan?

The microbes that live in and on humans may have evolved to preferentially take down the elderly in the population, a new computer model suggests.

That, in turn, could have allowed children a greater share of food and resources, thereby enabling an extended childhood. Such a microbial bias may also have kept the first human populations more stable and resilient to upheavals, the findings suggest.

"If you go back 30,000 to 40,000 years ago, there were only 30,000 to 40,000 people in the world and they were scattered over Africa, Europe, and parts of Asia," study co-author Glenn Webb, a mathematician at Vanderbilt University, said in a statement. "Are we lucky just to be here? Or did we survive because our ancestors were robust enough to handle all the environmental changes and natural disasters they encountered?"

The new findings suggest that humans survived because as a whole, ancestral human populations were tough enough to survive the environment, he said.


By some measures, the human body is more bacteria than human. The number of bacteria cells in the body outnumbers human cells by about 10 to 1. In recent years, scientists have found that this microbiome has far-reaching effects, modulating weight gain, mood and cognitive function.

Dr. Martin Blaser, a microbiologist at New York University's Langone Medical Center, began wondering about the effect of bacteria on age structure. He noticed that the stomach bacteria Helicobacter pylori, could live symbiotically in people's guts for decades, without causing them any harm, but it could also cause stomach ulcers and stomach cancer — a risk that grows with age.

"I began thinking that a real symbiont is an organism that keeps you alive when you are young and kills you when you are old. That’s not particularly good for you, but it’s good for the species," Blaser said.

It's possible that these bacteria helped reduce the number of elderly people in a population, thereby allowing the children to get a greater share of food and resources, the researchers said. In other words, the bacteria enable the extraordinarily long childhood that humans experience relative to other animals.

Modeling bacteria

To look at the microbiome's effects on people as they age, Blaser and Webb created a mathematical model to simulate an ancient hunter-gatherer population.

In their model, they assumed that the people had the same maximum life span that modern humans do, of about 120 years. (Though early hunter-gatherers had a lower life expectancy than humans that was due to other factors, such as childhood diseases, physical injuries that couldn't be healed and microbial diseases that can now be treated with antibiotics.)

The model grouped people into one of three groups: youngsters, people of reproductive age, and those past their reproductive years. Then the researchers watched how the population changed based on different fertility and mortality rates.

To capture the effects of "bacteria," they tweaked the mortality factors associated with different types of microbes.

Read more at Discovery News