Mar 9, 2012
In the study, scientists with the Astrobiology Analytical Laboratory at NASA's Goddard Space Flight Center in Greenbelt, Md., analyzed samples from fourteen carbon-rich meteorites with minerals that indicated they had experienced high temperatures -- in some cases, over 2,000 degrees Fahrenheit. They found amino acids, which are the building blocks of proteins, used by life to speed up chemical reactions and build structures like hair, skin, and nails.
Previously, the Goddard team and other researchers have found amino acids in carbon-rich meteorites with mineralogy that revealed the amino acids were created by a relatively low-temperature process involving water, aldehyde and ketone compounds, ammonia, and cyanide called "Strecker-cyanohydrin synthesis."
"Although we've found amino acids in carbon-rich meteorites before, we weren't expecting to find them in these specific groups, since the high temperatures they experienced tend to destroy amino acids," said Dr. Aaron Burton, a researcher in NASA's Postdoctoral Program stationed at NASA Goddard. "However, the kind of amino acids we discovered in these meteorites indicates that they were produced by a different, high-temperature process as their parent asteroids gradually cooled down." Burton is lead author of a paper on this discovery appearing March 9 in Meteoritics and Planetary Science.
In the new research, the team hypothesizes the amino acids were made by a high-temperature process involving gas containing hydrogen, carbon monoxide, and nitrogen called "Fischer-Tropsch" -type reactions. They occur at temperatures ranging from about 200 to 1,000 degrees Fahrenheit with minerals that facilitate the reaction. These reactions are used to make synthetic lubricating oil and other hydrocarbons; and during World War II, they were used to make gasoline from coal in an attempt to overcome a severe fuel shortage.
Researchers believe the parent asteroids of these meteorites were heated to high temperatures by collisions or the decay of radioactive elements. As the asteroid cooled, Fischer-Tropsch-type (FTT) reactions could have happened on mineral surfaces utilizing gas trapped inside small pores in the asteroid.
FTT reactions may even have created amino acids on dust grains in the solar nebula, the cloud of gas and dust that collapsed under its gravity to form the solar system. "Water, which is two hydrogen atoms bound to an oxygen atom, in liquid form is considered a critical ingredient for life. However, with FTT reactions, all that's needed is hydrogen, carbon monoxide, and nitrogen as gases, which are all very common in space. With FTT reactions, you can begin making some prebiotic components of life very early, before you have asteroids or planets with liquid water," said Burton.
In the laboratory, FTT reactions produce amino acids, and can show a preference for making straight-chain molecules. "In almost all of the 14 meteorites we analyzed, we found that most of the amino acids had these straight chains, suggesting FTT reactions could have made them," said Burton.
It's possible that both Strecker and FTT processes could have contributed to the supply of amino acids in other meteorites. However, evidence for the FTT reaction would tend to get lost because FTT reactions create them in much lower abundances than Strecker synthesis. If an asteroid with an initial amino acid supply from FTT reactions was later altered by water and Strecker synthesis, it would overwrite the small contribution from the FTT reactions, according to the team.
The team believes the majority of the amino acids they found in the 14 meteorites were truly created in space, and not the result of contamination from terrestrial life, for a few reasons. First, the amino acids in life (and in contamination from industrial products) are frequently linked together in long chains, either as proteins in biology or polymers in industrial products. Most of the amino the amino acids discovered in the new research were not bound up in proteins or polymers. In addition, the most abundant amino acids found in biology are those that are found in proteins, but such "proteinogenic" amino acids represent only a small percentage of the amino acids found in the meteorites. Finally, the team analyzed a sample of ice taken from underneath one of the meteorites. This ice had only trace levels of amino acids suggesting the meteorites are relatively pristine.
The experiments showing FTT reactions produce amino acids were performed over 40 years ago. The products have not been analyzed with modern techniques, so the exact distributions of amino acid products have not been determined. The team wants to test FTT reactions in the laboratory using a variety of ingredients and conditions to see if any produce the types of amino acids with the abundances they found in the 14 meteorites.
The team also wants to expand their search for amino acids to all known groups of carbon-rich meteorites. There are eight different groups of carbon-rich meteorites, called "carbonaceous chondrites." The new work adds two additional groups to the three previously known to have produced amino acids, leaving three groups to be tested. These three remaining groups have a high metal content as well as evidence for high temperatures. "We'll see if they have amino acids also, and hopefully gain some insight into how they were made," says Burton. When the team began looking for amino acids in carbon-rich meteorites, it was considered somewhat of a long shot, but now: "We would be surprised if we didn't discover amino acids in a carbon-rich meteorite," says Burton.
Read more at Science Daily
What the spiders were doing was creating a line of silk not webs, an entomologist has told Discovery News. The arachnid at the root of the story, a wolf spider, doesn't even make webs.
So, what these images show are massive amounts of dragline silk released by the normally solitary spiders as they ran for their lives to escape rising floodwaters. According to Reuters, flooding forced more than 8000 human residents from their homes in the city of Wagga Wagga, New South Wales.
And the spider residents were equally affected too.
“Wolf spiders would rather be hiding somewhere, trying to escape birds and other predators, but when land gets so flooded the spiders are forced to flee into trees and other high things,” Steve Heydon, senior museum scientist at the Bohart Museum of Entomology, University of California at Davis, told Discovery News.
“These spiders leave behind a dragline of silk, so the spiders at these places in Australia must be nervously running into each other, marching around in search of food,” he added. “There is clearly a lot of spider activity, as evidenced by the massive amounts of silk.”
Owen Seeman, an arachnid expert at Queensland Museum, identified the spider in question as “a type of wolf spider.” These are common spiders throughout the world, with 130 species documented in Australia alone.
Wolf spiders do not make webs, which many other spiders use to capture prey.
“Wolf spiders are instead like mini tigers that run and pounce on prey at night,” Heydon said.
In some of the news stories about the Australian spider silk “storm,” at least one expert, the Australian Museum’s entomology collections manager Graham Milledge, has been quoted as saying that the spiders were “ballooning.” Andy Reynolds, a scientist at Rothamsted Research, has studied this phenomenon before.
Reynolds explained that spiders “could use ballooning to cover long distances.” Each spider casts a thread of silk into the breeze and rides wind currents away from danger or parachutes into new areas.
Reynolds said the silk “can contort and twist with turbulence, affecting its aerodynamic properties and carrying its rider unpredictable distances.”
Heydon believes it is possible that some of the images showing the spider silk after the Australian flood could indeed be evidence of ballooning. But for wolf spiders, he said, this happens more often among younger, smaller individuals.
“Ballooning is a useful technique in the spider toolkit,” he said. “Some spiders can go to the end of a blade of grass or other starting point and release silk into the air so much that wind lifts it and carries the spider off.”
Spiders “balloon” all across the United States, but many of us probably miss the activity. Heydon, however, notices it all of the time, and even at his university’s sporting events.
“At night, if you look at the big lights in our athletic fields, you can sometimes see long streamers of silk from ballooning spiders flying high into the air,” he explained.
Clearly certain parts of Australia are inundated with such spiders, resulting in the dramatic photos showing everything from a farm to a family dog covered in spider silk after the flood.
Read more at Discovery News
The newly discovered fossil of Microraptor lived about 130 million years ago, during the early Cretaceous period, in what is now northeastern China. The latest depictions of the beast, whose feathery adornments may have extended to other Microraptor species, suggest it looked similar to a crow, even though non-avian dinosaurs had already separated from the ancestors of modern birds by that time.
It may have looked like a crow, but researchers also think it may have flashed its tail feathers in the manner of a peacock.
The researchers analyzed the fossil feathers using a scanning electron microscope to see melanosomes, tiny structures (about one-hundredth as wide as a human hair) that give feathers their colors.
The researchers compared the arrangement of these melanosomes with those of modern birds. When melanosomes are stacked neatly, the feather looks darker; when they are more disorganized, the feather appears lighter.
From their analysis of modern birds, the researchers figured that this Microraptor fossil had black feathers. Furthermore, the narrow stacking of the melanosomes would have given the feathers iridescence. The researchers couldn't be sure of the color of the sheen, or the effect of the iridescence on the feather color, because those factors depend on the thickness of the feather's keratin coat.
"That keratin is not preserved in the fossil, so we couldn't directly infer a particular color of iridescence," said study researcher Matthew Shawkey, an assistant professor at the University of Akron, in Ohio.
For their drawings of the dinosaur, the researchers went with a middle-of-the road estimate.
Shake your tail feathers
Microraptor also had elongated tail feathers, which were much better preserved in this new specimen than in previous fossils. (The first Microraptor was unearthed in 2003.) The researchers could see these feathers were narrower and longer than previous extimates.
Read more at Discovery News
One likely place for a repeat performance is the west coast of North America. The question is when.
Geophysicists from seven research institutions across the country are probing that question like never before, through a five-year, $4.6-million project just getting underway. Combining 1,000-times-faster computing speeds with improved methodologies, the team is creating the first unified simulation of earthquakes all along western North America.
“One of the project goals is to improve our short- and long-term earthquake forecasting capabilities,” project leader James Dieterich of the University of California, Riverside, said in a press release. “More accurate forecasting has practical advantages—earthquake insurance, for example, relies heavily on forecasts.”
The new simulation will help scientists determine the interplay between the two very different fault systems that exist along the U.S. West Coast. Californians have known to expect great lurches along the San Andreas Fault and its counterparts ever since the Great San Francisco Earthquake of 1906. But inhabitants of the U.S. Pacific Northwest face a double threat: Lurking offshore is a 600-mile-long gash in the seafloor, the Cascadia Subduction Zone, that is prone to mega-thrust earthquakes and tsunamis on the order of last year’s 9.0 tsunami-generating temblor in Japan. The last great Cascadia quake occurred in 1700, uncomfortably long ago when you consider that such events occur every 300 to 500 years.
“Observations of earthquakes go back to only about 100 years, resulting in a relatively short record,” Dieiterich said. “If we get the physics right, our simulations of plate boundary fault systems—at one-kilometer resolution for California—will span more than 10,000 years of plate motion and consist of up to a million discrete earthquake events, giving us abundant data to analyze.”
From all that new data, Dieterich and his colleagues hope to locate clues regarding the long-term processes that condition fault systems to fail in great earthquakes (greater than magnitude 8). One condition the team will be watching closely is the effect of so-called slow-slip events, a special class of subtle plate motion among the hundreds of earthquakes we cannot feel at the earth’s surface.
The existence of slow-slip events, which scientists discovered only recently, is turning out to be especially important for accurate forecasting. In a slow-slip event, movement is gradual enough not to create detectable ground motion, but the energy release can be the equivalent of a normal magnitude 6 earthquake. The big question is whether these events may transfer stress to portions of a subduction zone most prone to a violent jolt, Dieterich explained in a recent talk on the UC Riverside campus.
He pointed out that scientists reviewing the seismic recordings from Japan in early 2011 noted a slow-slip event occurred between the main shock on March 11 and its foreshock.
Read more at Discovery News
Mar 8, 2012
According to the study's lead author, Xie Shucheng of the China University of Geosciences at Wuhan, the identification of ancient droughts and associated alkaline soils is particularly challenging at the regional or local level, and is beyond the predictive capabilities of available general circulation models (GCMs). GCMs, which are used to understand physical processes in Earth surface system, are advanced tools for simulation of long-term temperature change.
This new research proposes a microbial lipid proxy of highly alkaline conditions and enhanced aridity on the basis of investigation of modern Chinese soils. In modern Chinese soils, more abundant archaeal lipids known as iGDGTs (isoprenoid glycerol dialkyl glycerol tetraethers) relative to bacterial branched GDGTs were found to be associated with alkaline conditions and enhanced aridity. As a consequence, the ratio of archaeal GDGTs to bacterial GDGTs is indicative of the occurrence of ancient alkalinity and enhanced aridity.
Xie and colleagues also used the microbial lipid proxy to identify the enhanced aridity and alkalinity of Late Miocene sediments from the Zhada basin, which is located in the southwestern Tibetan Plateau, ~1000 km west of Lhasa. They find that the highly alkaline conditions and enhanced aridity identified in these sediments are associated with the most significant uplift of the Tibetan Plateau nine million years ago. The study's findings suggest that abrupt uplifts in the Tibetan Plateau can cause enhanced aridity in central Asia and a consequential development of alkaline soils.
Read more at Science Daily
The finding provides insight into the evolution of life -- particularly, early life -- on the planet, why animals go extinct, and how organisms respond to environmental changes. The discovery also can help scientists recognize life elsewhere in the universe.
The Ediacaran Period, named after the Ediacara Hills of South Australia, ranges 630-542 million years ago. The Cambrian Period, marked by a rapid diversification of life-forms on Earth as well as the rise of mineralized organisms, ranges 542-488 million years ago.
The best Coronacollina specimens showing the main body with articulated spicules. Specimens originate from different field localities. Arrows indicate main body of Coronacollina. White/black bars indicate 1 cm. A, C, D and E are photographs of fossil impressions in the rock. B and F are latex casts showing how the fossils would have looked in life, after compression. Image credit: Droser lab, UC Riverside.
"Up until the Cambrian, it was understood that animals were soft bodied and had no hard parts," said Mary Droser, a professor of geology at the University of California, Riverside, whose research team made the discovery in South Australia. "But we now have an organism with individual skeletal body parts that appears before the Cambrian. It is therefore the oldest animal with hard parts, and it has a number of them -- they would have been structural supports -- essentially holding it up. This is a major innovation for animals."
Coronacollina acula is seen in the fossils as a depression measuring a few millimeters to 2 centimeters deep. But because rocks compact over time, the organism could have been bigger -- 3 to 5 centimeters tall. Notably, it is constructed in the same way that Cambrian sponges were constructed.
"It therefore provides a link between the two time intervals," Droser said. "We're calling it the 'harbinger of Cambrian constructional morphology,' which is to say it's a precursor of organisms seen in the Cambrian. This is tremendously exciting because it is the first appearance of one of the major novelties of animal evolution."
According to Droser, the appearance of Coronacollina acula signals that the initiation of skeletons was not as sudden in the Cambrian as was thought, and that Ediacaran animals like it are part of the evolutionary lineage of animals as we know them.
"The fate of the earliest Ediacaran animals has been a subject of debate, with many suggesting that they all went extinct just before the Cambrian," she said. "Our discovery shows that they did not."
Study results appeared online Feb. 14 in Geology.
The researchers note that Coronacollina acula lived on the seafloor. Shaped like a thimble to which at least four 20-40-centimeter-long needle-like "spicules" were attached, Coronacollina acula most likely held itself up by the spicules. The researchers believe it ingested food in the same manner a sponge does, and that it was incapable of locomotion. How it reproduced remains a mystery.
Coronacollina acula is so named because it translates as "little rimmed hill with needles" (corona -- rim or crown; collis -- hill; acula -- needle). The name describes the fossil organism's morphology, and, specifically, its two components: the truncated cone-shaped body, which appears in the fossils as a pit, and the long brittle spicules, which appear in the fossils as thin grooves.
Ediacaran fossils often show the imprint of the whole body of the organism. With Coronacollina acula, however, skeletal parts were found to have fallen off.
"If you have soft parts holding your body together, then, as they decay, you lose your skeletal parts," Droser explained. "Which is why it's rare to find two clam shells together in fossils. We've now found whole organisms of Coronacollina acula -- the thimble-shaped body in the center, with spicules coming off it like knitting needles. And we have found hundreds of them. They appear to have been a gregarious species, with a lot of them living together."
Droser explained that the spicules had to have been mineralized because the casts show they are ruler-straight. Moreover, they broke.
"We often associate skeletons with predation since skeletons greatly assist animals in their fight against predators," Droser said. "But Coronacollina acula used its skeleton only for support, there being no predators in the Ediacaran."
The research work began as a master's thesis project in Droser's lab. Erica Clites, now a physical science technician at Glen Canyon National Recreation Area for the National Park Service, chose to work on this project because it promised a good challenge with rewarding results.
"Every aspect of the organism's reconstruction had to be backed up by supporting statistics," said Clites, who graduated from UCR in 2009 and is the first author of the research paper. "Through painstaking measurements and detailed descriptions, the pits and needles contained in the rock were revealed as a sponge-like animal."
Read more at Science Daily
In both, certain genes have also evolved at the same rate, research shows. They include genes for hearing, throwing into doubt theories linking the development of hearing and human language.
The findings emerge from the first completed genome sequence, or genetic "blueprint", of the gorilla.
Gorillas are the last of the living great apes to have their genetic codes mapped, allowing scientists to compare the genomes of humans, chimpanzees, gorillas and orang-utans.
The new research was chiefly based on DNA taken from Kamilah, a female western lowland gorilla.
Scientists at the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, searched more than 11,000 genes in the gorilla, human and chimpanzee looking for important evolutionary differences.
In all three species, genes related to sensory perception, hearing and brain development showed accelerated evolution. But this was especially true for humans and gorillas.
Dr Chris Tyler-Smith, senior author of the research published in the journal Nature, said: "Our most significant findings reveal not only differences between the species reflecting millions of years of evolutionary divergence, but also similarities in parallel changes over time since their common ancestor.
"We found that gorillas share many parallel genetic changes with humans including the evolution of our hearing.
"Scientists had suggested that the rapid evolution of human hearing genes was linked to the evolution of language.
"Our results cast doubt on this, as hearing genes have evolved in gorillas at a similar rate to those in humans."
Gorillas separated from humans and chimpanzees on the evolutionary path around 10 million years ago, the research showed.
A more gradual divergence between eastern and western gorillas occurred much more recently in the last million years or so.
This could be compared with the split between modern humans and Neanderthals, or chimpanzees and bonobos, said the scientists.
Co-author Dr Aylwyn Scally, also from the Sanger Institute, said: "The gorilla genome is important because it sheds light on the time when our ancestors diverged from our closest evolutionary cousins.
"It also lets us explore the similarities and differences between our genes and those of gorilla, the largest living primate.
"Using DNA from Kamilah, a female western lowland gorilla, we assembled a gorilla genome sequence and compared it with the genomes of the other great apes.
Read more at The Telegraph
The king's name, Senakht-en-Re, emerged from the engraved remains of a limestone door found by a French-Egyptian team in the Temple of Karnak complex on Luxor’s east bank.
The archaeologists, led by French Egyptologist Christophe Thiers, of the Centre National de la Recherche Scientifique (CNRS), unearthed a fragmented lintel and an imposing door jamb during routine excavation at the temple of Ptah.
Belonging to an administrative structure dating to the enigmatic 17th Dynasty (about 1634-1543 BC) the limestone remains featured hieroglyphics which indicated that the door was dedicated to Amun-Re.
"They also revealed who ordered the construction of this structure. It was the pharaoh Senakht-en-Re," said a CNRS statement.
Mentioned in only three documents written one or two centuries after his reign, Senakht-en-Re is regarded as one of the most obscure kings of the 17th dynasty.
No objects or monuments had ever been found bearing his name, and his tomb has yet to be discovered.
"We knew nothing of this pharaoh - until now. These remains are the first contemporary document of this king ever discovered in Egypt," the CNRS said.
According to the hieroglyphics, Senakht-en-Re had the monumental gateway built from limestone blocks transported from Tora (the modern Helwan, south of Cairo).
At that time, the town was under the rule of the Hyksos. Known as the "rulers of foreign countries" (probably of Asiatic roots), they infiltrated Egypt and came to dominate the Nile valley for over a century during the Second Intermediate Period (1664-1569 B.C.).
Read more at Discovery News
Mar 7, 2012
Key to the experiment, which appears in the journal Nature, is the researchers' use of the energy of a single electron as a kind of "flash bulb" to illuminate the reaction.
The team used ultrafast laser pulses to knock one electron out of its natural orbit in one of the atoms, just as the two atoms were bonding together. When the electron fell back into place, it emitted an energy signal that scattered around the newly forming molecule as a flash of light would scatter around an object, or ripples would scatter in a pond.
Principal investigator Louis DiMauro of Ohio State University said that the feat marks a first step toward not only observing chemical reactions, but also controlling them on an atomic scale.
"Through these experiments, we realized that we can control the trajectory of the electron when it comes back to the molecule, by adjusting the orientation of the laser that launches it," said DiMauro, who is a professor of physics at Ohio State. "The next step will be to see if we can hit the electron in just the right way to actually control a chemical reaction."
A more common imaging technique involves shooting a molecule with an electron beam, bombarding it with millions of electrons per second. The researchers deemed the new single-electron approach more reliable, based on theoretical developments by the paper's coauthors at Kansas State University.
"If we shot an electron beam from outside the molecule, there would only be a certain probability that one of the electrons would scatter off the molecule," explained Ohio State postdoctoral researcher Cosmin Blaga. "But in this case, when we use a laser to launch an electron from inside the molecule we are studying, we have a 100 percent probability that it will fall back into the molecule and scatter."
The technique, called laser induced electron diffraction (LIED), is commonly used in surface science to study solid materials. This is the first time anyone has used LIED to study a single molecule as it formed.
The molecules the researchers chose to study were simple ones: they brought two nitrogen atoms together to form molecular nitrogen, or N2, then repeated the experiment with two oxygen atoms forming molecular oxygen, or O2. N2 and O2 are common atmospheric gases, and scientists already know every detail of how they form, so these two very basic reactions made good test cases for the LIED technique.
In each case, the researchers hit the forming molecule with laser light pulses of 50 femtoseconds, or quadrillionths of a second. They were able to knock a single electron out of the outer shell of one of the constituent atoms and detect the energy signal of the electron as it fell back into the molecule.
DiMauro and Blaga likened the electron signal to the diffraction pattern that light forms when it passes through slits. Given only the diffraction pattern, scientists can reconstruct the size and shape of the slits. In this case, given the diffraction pattern of the electron, the physicists reconstructed the size and shape of the molecule -- that is, the locations of the constituent atoms' nuclei and the electron shells orbiting them.
The resulting 3D image marks the first image ever recorded of bonds forming in a molecule.
Beyond its potential for controlling chemical reactions, the technique offers a new tool to study the structure and dynamics of matter, Blaga said. "Ultimately, we want to really understand how chemical reactions take place. So, long-term, there would be applications in materials science and even chemical manufacture."
"You could use this to study individual atoms," DiMauro added, "but it's safe to say that we won't learn anything new from an atomic physics standpoint. The greater impact to science will come when we can study reactions between more complex molecules. Looking at two atoms -- that's a long way from studying a more interesting molecule like a protein."
Read more at Science Daily
Covered in vomit, the nestlings not surprisingly become less attractive as a snack, the team says.
But the smell also alerts parents, returning to the nest, that a threatening incident has happened in their absence, they believe.
The scientists tested the "olfactory cue" theory by visiting nests with 10-day-old nestlings inside.
They used a small paintbrush to daub a tiny amount of either lemon juice or vomit on the inside of the nest. Parents returning to a vomit-treated nest reacted with great caution, delaying the time when they would settle in the home.
Previous research has found that birds have a surprisingly wide range of defensive reactions.
For instance, the northern fulmar (Fulmaris glacialis) yawks up stomach oils against intruders that makes them lose their waterproof coating.
And the common eider (Somateria mollissima) and northern shoveler (Anas acuta) have the ability to spray feces on their eggs to deter mammal egg-thieves.
However, the Eurasian roller is the first bird that has been found to use a scent, derived in response to a threat, as a means of communication, says the paper.
Read more at Discovery News
The results come from the now-defunct Tevatron collider, which closed down in September after nearly a quarter century, though physicists continue to analyze its data in the hunt for the so-called "God particle."
The Higgs boson is the missing link in the standard model of physics and is believed to be what gives objects mass, though scientists have never been able to pin it down and it exists only in theory.
"The end game is approaching in the hunt for the Higgs boson," said Jim Siegrist, Department of Energy associate director of science for high energy physics.
"This is an important milestone for the Tevatron experiments, and demonstrates the continuing importance of independent measurements in the quest to understand the building blocks of nature."
Physicists from the CDF and DZero collaborations at Fermi National Acceleratory Laboratory in Illinois said in a statement that their data "might be interpreted as coming from a Higgs boson with a mass in the region of 115 to 135 GeV (gigaelectronvolts)."
That result includes the slightly more narrow constraints announced in December 2011 by scientists at CERN's Large Hadron Collider -- the world's largest atom-smasher, located along the French-Swiss border.
The CERN (European Center for Nuclear Research) experiments, carried out by a consortium of 20 member nations, have shown a likely range for the Higgs boson between 115 to 127 GeV.
GeV is the standard measure for the mass of sub-atomic particles. One GeV is roughly equivalent to the mass of a proton.
However, none of the hints so far have been enough for physicists to announce that the particle has been "discovered," or to claim there is enough evidence to say for certain that it exists.
Fermilab director Pier Oddone said he was "thrilled with the pace of progress in the hunt for the Higgs boson," noting that scientists from around the world have combed through hundreds of trillions of proton-antiproton collisions.
Read more at Discovery News
Cold seeps are essentially pools of methane-rich lakes on the ocean floor. Highly-saline methane and other hydrocarbon-rich fluids seep through the crust and pool on the seafloor. But add a volcanic seamount to the geologic mix, and now that same fluid gets heated as it moves through the crust.
The percolating hot fluids cool quickly once mixed with the freezing ocean waters, and it is the chemicals raining down from that mixture that build chimney formations -- those classic ebony/ivory hydrothermal vent smokers, some black (hot) and some white (warm) for example.
"The site had been visited by other researchers using remotely operated vehicles," said lead author Lisa Levin of the Scripps Institution of Oceanography in La Jolla, Calif. in a statement. "But it wasn't until human eyes saw shimmering water flowing under a tubeworm 'bush' that we really understood how special Jaco Scar is."
Until then, the seamount was a known methane seep, but not considered hydrothermally active. Levin and her colleagues announced their findings today in the journal Proceedings of the Royal Society B: Biological Sciences.
I had a chance to see just such shimmering during a dive on the volcanic seamount Menez Gwen in the Azores with the Mir submersibles in 2003. The sediments on the seamount were such that as we pushed down with the manipulator arm to pick up a rock, a jet of hot fluid erupted nearby.
Bacteria, archea, and other organisms thrive on these marine geofluid chemicals whether they be hot or cold, but the temperature of the fluid here at Jaco Scar is key, as that is what determines what gets mixed into the solution when the fluid is traveling through the crust and -- consequently -- what falls out of solution once it reaches the seafloor sediments and mixes with ocean water.
Different organisms take advantage of different chemicals. At Jaco Scar, hydrothermal vent ogranisms are living next to cold seep organisms.
Read more at Discovery News
Mar 6, 2012
The findings will be published in the Astrophysical Journal Letters.
Remarkably, the cluster was completely missed by previous surveys, which searched this region of the sky for thousands of hours and were conducted by all the major ground- and space-based observing facilities, including the Hubble Space Telescope. Despite these intense observations, accurate distances for such faint and distant galaxies were missing until the advent of FourStar.
Eric Persson of the Carnegie Observatories* led the development of the new camera that enabled these observations. Persson and his team--which includes Carnegie's David Murphy, Andy Monson, Dan Kelson, Pat McCarthy, and Ryan Quadri--equipped FourStar with five special filters to collect images that are sensitive to narrow slices of the near-infrared spectrum. This powerful approach allows them to measure accurate distances between Earth and thousands of distant galaxies at one time, providing a 3-D map of the early universe.
The 3-D map revealed the conspicuous concentration of galaxies that existed when the universe was only three billion years old.
"This means the galaxy cluster is still young and should continue to grow into an extremely dense structure possibly containing thousands of galaxies," explained lead author Lee Spitler of Australia's Swinburne University of Technology. Studying this system will help astronomers understand how galaxies are influenced by their environment, evolve, and assemble into larger structures.
The finding is part of a larger survey, the FourStar Galaxy Evolution Survey ("Z-FOURGE"), led by Dr. Ivo Labbé, a former Carnegie postdoctoral fellow, now at Leiden Observatory in the Netherlands. The focus of the survey is to address a classical problem in observational astronomy: determining distances. Only then do you know if a point of light is a star in our Milky Way, a small nearby galaxy, or a large one very far away.
The Z-FOURGE observations are being conducted using the Magellan 6.5- meter telescope at Carnegie's Las Campanas Observatory in Chile. From the first six months of the survey, the team obtained accurate distances for faint galaxies over a region roughly one-fifth the apparent size of the Moon. Though the area is relatively small, they found about a thousand galaxies at even greater distances than the new cluster.
Read more at Science Daily
And math is tough for many people, but a new study from the Girl Scout Research Institute finds encouraging news about girls' interest in (and confidence about) science, technology, engineering and math (STEM).
Contrary to the Barbie stereotype, many girls are interested in these subjects, perhaps inspired by women like Danica McKellar, an actress best known for her roles on "The Wonder Years" and "The West Wing."
But McKellar isn't just another pretty face; she's also a math whiz, having graduated summa cum laude in mathematics from the University of California at Los Angeles, and written several books including "Math Doesn’t Suck: How to Survive Middle-School Math Without Losing Your Mind or Breaking a Nail."
Actually, the widely-repeated Barbie quote above is incorrect; she really said "Math class is tough." And like the Barbie quote, the perception that girls don't feel smart enough to do math (or aren't interested in it) isn't quite true either: The study finds that 74 percent of teen girls are interested in STEM subjects.
As to why girls are drawn to STEM subjects, the study finds that girls take an active, inquisitive approach to engaging in science often thought of as boys' behavior. Eighty-five percent of these gender-stereotype-busting girls like to solve problems; 67 percent like to build things and put things together; 83 percent like to do hands-on science projects; and 80 percent ask questions (and seek answers) about how things work.
Confidence in Math and Science
One of the most encouraging findings from the study is that “a high 82 percent of girls see themselves as smart enough to have a career in STEM.” The report also found that girls are similarly confident and optimistic about their intelligence, abilities and future. For example, nearly all (97 percent) girls say they will graduate from college, and a high percentage (84 percent) expect to attend graduate school.
This is important because low confidence in a person's abilities can result in a self-defeating, self-fulfilling prophecy. Gender stereotypes are hard to break, and social pressures reflecting the stereotype that girls are not good at (or ill-suited for) math and science may unconsciously discourage girls.
For example, educators have observed that mothers encourage their sons more than their daughters to engage in hands-on activities in science museums.
Read more at Discovery News
At a ceremony in Washington, D.C. this morning, forensic researchers released new images of the pair's reconstructed faces as a way of trying to finally lay the men to rest.
"This is a last-ditch effort to identify them," said David Alberg, superintendent of the USS Monitor National Marine Sanctuary. "We're trying to shake some family trees."
Officials from the National Oceanic and Atmospheric Administration, Navy and a forensics lab at Louisiana State University have been working on the project for the past 10 years, ever since the Monitor's turret was raised from the seafloor during archaeological excavation in 2002.
They employed the same genetic fingerprinting and facial reconstruction techniques that have been used to identify soldiers missing in action or crime victims.
DNA testing from samples in the teeth and leg bones did not find a match with any living descendants of the ship's crew of families. But they did have two skulls, and were able to recreate the two men's faces. By poring over old records -- from Navy pension requests to old ship logs -- researchers believe they have narrowed the field on this Civil War mystery.
One was a Welshman named Robert Williams, who was likely in his early 30s and about 5 foot 6 inches tall. He smoked a pipe, served on two other Navy ships before joining the Monitor, and may have been a fireman. He also had arthritis and likely suffered from syphilis, according to Lisa Stansbury, a genealogist working with NOAA.
The second set of remains is of a younger man between 17 and 24 years old. He could be one of three people: William Eagan of Ireland; Jacob Nicklis of Buffalo, N.Y.; or Samuel Auge Lewis of West Chester, Pa. He was about 5 foot, 7 inches tall.
Both men were white, although the Monitor's crew included at least one African-American.
While Stansbury was able to narrow down a list of names for the two, she isn't 100 percent positive. That's because sailors sometimes gave false names while enlisting, perhaps to avoid a shady past or in case they didn't like the ship, they could desert, and later re-enlist under a different identity.
"We really don't have more than a theory," Stansbury said about their identities.
Stansbury said she hopes that families with descendants from that time period may now come forward, provide DNA samples, and make a positive match.
The huge effort to identify the two men stems from great interest in the Monitor, a ship that President Abraham Lincoln praised as the savior of the Union.
At the time, the Confederate CSS Virginia (built on the hull of the navy frigate Merrimack) was ravaging the federal fleet at Hampton Roads. The Monitor -- a smaller, more nimble ship with a swiveling "cheesebox" gun turret on its deck, was built in 1862 in Brooklyn.
Read more at Discovery News
By observing captured freshwater-dwelling Pristis microdon sawfishes, scientists have found the fish use sensors in their saws to detect other fish, their prey, and to swipe at them with enough force to impale their dinner.
The team, led by Barbara Wueringer of the University of Queensland in Australia, found that the sawfishes tore into the already dead fish they were fed, swiping side-to-side several times per second. The swipes were strong enough to split the fish in half.
The sawfish then used their snouts to pin their meal onto the bottom of the aquarium to eat it.
Scientists already knew that freshwater sawfishes — which hunt in murky waters along coastlines and in rivers — have tiny receptors on their saws that pick up on electrical fields produced by their prey, as well as sensors that detect movements in the water.
In the new research, the scientists used weak electrical fields to simulate prey, and watched as the sawfish responded.
Previously, scientists had observed another species of sawfish, Pristis pectinata, attacking pieces of fish floating in the water, suggesting its use in obtaining food. It has also been suggested that sawfish use their saws to rake through the sand to find buried prey, cut chunks out of whales and slash at schooling fish, according to Wueringer and colleagues.
The new study, detailed in the March 6 issue of the journal Current Biology, suggests their saws make them agile hunters, not just for their sensory features but also for their capability of sawing into prey.
"Sawfish are skilled predators but, ironically, the saw is partly to blame for their global decline: The saw is easily entangled in fishing gear, perhaps as a result of targeting prey caught in the net," they write.
Read more at Discovery News
Mar 5, 2012
Eizo Nakamura and colleagues at Okayama University and the Japan Aerospace Exploration Agency (JAXA) report the results from a study of the samples in the Proceedings of the National Academy of Sciences.
The Japan Aerospace Exploration Agency (JAXA) sent a probe to investigate the near-Earth asteroid 25143 Itokawa as part of the Hayabusa mission. The aim of the mission was to obtain and analyse samples of asteroids and so learn more about how the solar system evolved.
Asteroids are considered to comprise intermediate products in the evolution of solar bodies. Investigating asteroids can provide information on planetary evolution. The information that can be retrieved from meteorites -- asteroids that fall to earth -- is limited as a result of the significant surface changes meteorites undergo when they enter the atmosphere. In contrast the Itokawa samples comprised 'chondritic' material, unmodified by this sort of melting or differentiation.
The capsule containing the asteroid grains returned to Earth in June 2010. Mass spectroscopy analysis confirmed that the oxygen isotope ratios differed from stone found on Earth, confirming the extra-terrestrial origin of at least 4 of the 5 samples.
Using scanning electron microscopy, the researchers identified craters 100-200 nm in size as well as particles adhered to the asteroid surface. They suggest that a combination of disaggregation, cratering, melting, adhesion, agglutination, and implantation/sputtering affect the asteroid surface as a result of bombardment by submicrometre sized particles in space. "Impact appears to be an important process shaping the exteriors of not only large planetary bodies, such as the moon, but also low-gravity bodies such as asteroids," explain Nakamura and his colleagues.
Among the other features observed in the grains were a type of feldspar that would have formed during slow cooling from temperatures of 860 °C. These temperatures and cooling dynamics could not have been achieved in a rock with a radius of only 300m. As a result it is likely that the asteroid Itokawa originated from a larger asteroid.
The researchers identified a considerable number of glassy particles on the asteroid surface, as well as iron particles associated with weathering processes in space from previous spectroscopy studies. However, they also suggest that previous near-infrared spectrocsopy studies may have underestimated the deposition of glassy materials and the resulting absorption.
Read more at Science Daily
So he ordered eight spiders -- Nephila clavipes, golden silk orbweavers -- and put them to work eating crickets and spinning webs in the cages he set up in an Iowa State University greenhouse.
Wang, an associate professor of mechanical engineering at Iowa State, studies thermal conductivity, the ability of materials to conduct heat. He's been looking for organic materials that can effectively transfer heat. It's something diamonds, copper and aluminum are very good at; most materials from living things aren't very good at all.
But spider silk has some interesting properties: it's very strong, very stretchy, only 4 microns thick (human hair is about 60 microns) and, according to some speculation, could be a good conductor of heat. But nobody had actually tested spider silk for its thermal conductivity.
And so Wang, with partial support from the Army Research Office and the National Science Foundation, decided to try some lab experiments. Xiaopeng Huang, a post-doctoral research associate in mechanical engineering; and Guoqing Liu, a doctoral student in mechanical engineering, helped with the project.
"I think we tried the right material," Wang said of the results.
What Wang and his research team found was that spider silks -- particularly the draglines that anchor webs in place -- conduct heat better than most materials, including very good conductors such as silicon, aluminum and pure iron. Spider silk also conducts heat 1,000 times better than woven silkworm silk and 800 times better than other organic tissues.
A paper about the discovery -- "New Secrets of Spider Silk: Exceptionally High Thermal Conductivity and its Abnormal Change under Stretching" -- has just been published online by the journal Advanced Materials.
"Our discoveries will revolutionize the conventional thought on the low thermal conductivity of biological materials," Wang wrote in the paper.
The paper reports that using laboratory techniques developed by Wang -- "this takes time and patience" -- spider silk conducts heat at the rate of 416 watts per meter Kelvin. Copper measures 401. And skin tissues measure .6.
"This is very surprising because spider silk is organic material," Wang said. "For organic material, this is the highest ever. There are only a few materials higher -- silver and diamond."
Even more surprising, he said, is when spider silk is stretched, thermal conductivity also goes up. Wang said stretching spider silk to its 20 percent limit also increases conductivity by 20 percent. Most materials lose thermal conductivity when they're stretched.
That discovery "opens a door for soft materials to be another option for thermal conductivity tuning," Wang wrote in the paper.
And that could lead to spider silk helping to create flexible, heat-dissipating parts for electronics, better clothes for hot weather, bandages that don't trap heat and many other everyday applications.
What is it about spider silk that gives it these unusual heat-carrying properties?
Wang said it's all about the defect-free molecular structure of spider silk, including proteins that contain nanocrystals and the spring-shaped structures connecting the proteins. He said more research needs to be done to fully understand spider silk's heat-conducting abilities.
Wang is also wondering if spider silk can be modified in ways that enhance its thermal conductivity. He said the researchers' preliminary results are very promising.
Read more at Science Daily
As the precursor of vertebrates the species is also believed to be the direct ancestor of all members of the chordate family, which includes fish, birds, reptiles, amphibians and mammals.
The finding means the 5cm long creatures, known as Pikaia gracilens, were the forerunners of animals as diverse as snakes, swans and humans, scientists said.
The fossils, preserved in shale beds in Canada, were first found 100 years ago by American paleontologist Charles Doolittle Walcott, who suggested they could have been an early type of leech or worm.
Scientists had since speculated that the creatures could have been chordates because they appeared to have a simple form of notochord, a flexible rod which makes up part of the backbone in vertebrates.
But because they lacked a fully developed backbone, there remained doubts about exactly which category of species the fossilised animals should fall into.
Now an analysis of 114 specimens by Cambridge University scientists and Canadian colleagues has identified lumps of skeletal muscle tissue known as myomeres, which appear to lay any doubts to rest.
Simon Conway Morris, lead author of the study published in the Biological Reviews journal, said: “The discovery of myomeres is the smoking gun that we have long been seeking.
“Now with myomeres, a nerve chord, a notochord and a vascular system all identified, this study clearly places Pikaia as the planet’s most primitive chordate."
Jean-Bernard Caron, a co-author on the paper, added: "It’s very humbling to know that swans, snakes, bears, zebras and, incredibly, humans all share a deep history with this tiny creature no longer than my thumb."
Read more at The Telegraph
The camels lived 20 million years ago and are now considered to be among the oldest known animals from Panama.
"They were probably browsers in the forests of the ancient tropics. We can say that because the crowns are really short," lead author Aldo Rincon, a University of Florida geology doctoral student, said in a press release.
Rincon and his team are working with the Panama Canal Authority and scientists at the Smithsonian Tropical Research Institute to make the most of a five-year window of excavations during Panama Canal expansions that began in 2009.
The new fossil camels, Aguascalietia panamaensis and Aguascalientia minuta, extend the distribution of mammals to their southernmost point in the ancient tropics of Central America.
Excavations are often difficult in the tropics because the lush vegetation prevents access. That's not such a bad thing, considering that these species-rich areas contain some of the world's most important ecosystems, including rain forests that regulate climate systems and serve as a vital source of food and medicine.
"We're discovering this fabulous new diversity of animals that lived in Central America that we didn't even know about before," said co-author Bruce MacFadden, vertebrate paleontology curator at the Florida Museum on the UF campus and co-principal investigator on the NSF grant funding the project.
"The family originated about 30 million years ago and they're found widespread throughout North America, but prior to this discovery, they were unknown south of Mexico."
Camels belong to a group of even-toed ungulates that includes cattle, goats, sheep, deer, buffalo and pigs. Other fossil mammals discovered in Panama from the early Miocene have been restricted to those also found in North America at the time.
While researchers are sure the ancient camels were herbivores that likely browsed in forests, they are still analyzing seeds and pollen to better understand the environment of the ancient tropics.
Read more at Discovery News
Mar 4, 2012
Psychologists have known for decades that what's going on inside our head affects our senses. For example, poorer children think coins are larger than they are, and hungry people think pictures of food are brighter. Rémi Radel of University of Nice Sophia-Antipolis, France, wanted to investigate how this happens -- whether it's right away, as the brain receives signals from the eyes, or a little later, as the brain's higher-level thinking processes get involved.
Radel recruited 42 students with a normal body mass index. On the day of his or her test, each student was told to arrive at the lab at noon after three or four hours of not eating. Then they were told there was a delay. Some were told to come back in 10 minutes; others were given an hour to get lunch first. So half the students were hungry when they did the experiment and the other half had just eaten.
For the experiment, the participant looked at a computer screen. One by one, 80 words flashed on the screen for about 1/300th of a second each, at a size that was just at the threshold of what that person could consciously perceive. A quarter of the words were food-related. After each word, the person was asked how bright the word was and asked to choose which of two words they'd seen -- a food-related word like gateau (cake) or a neutral word like bateau (boat). Each word appeared too briefly for the participant to really read it.
Hungry people saw the food-related words as brighter and were better at identifying food-related words. Because the word appeared too quickly for them to be reliably seen, this means that the difference is in perception, Radel says -- it's not because of some kind of processing happening in the brain after you've already figured out what you're looking at.
Read more at Science Daily
The new information on water fleas -- which are actually tiny crustaceans -- comes from a multi-year, international study that was published Feb. 24 in the journal Zootaxa.
The researchers scoured the globe seeking the creatures and found them inhabiting northern lakes and ponds in locations from Alaska to Russia to Scandinavia.
After analyzing the anatomy and genetic makeup of many different specimens, the team conclusively determined that at least 10 species of the crustaceans existed -- five times as many as thought for much of the last century.
More than half the diversity was found in northern latitudes, where rapid freshwater habitat loss is occurring due to melting permafrost, increased evaporation and other changes tied to climate change.
"It is well known that parts of Alaska and Siberia have suffered a huge reduction in freshwater surface area, with many lakes and ponds disappearing permanently in the past few decades," said Derek J. Taylor, a University at Buffalo biologist and member of the research team. "What we're now finding is that these regions with vanishing waters, while not the most diverse in the world, do contain some unique aquatic animals."
"Some of these subarctic ponds that water fleas inhabit are held up by permafrost, so when this lining of ice melts or cracks, it's like pulling the plug out of a sink," Taylor said. "When you see the crop circle-like skeletons of drained ponds on the tundra you can't help but wonder what animal life has been lost here."
Taylor's colleagues on the study included Eugeniya I. Bekker and Alexey A. Kotov of the A. N. Severtsov Institute of Ecology and Evolution in Moscow.
The research focused on water fleas of the genus Eurycercus, which can reach lengths of about 6 millimeters. The findings add to a body of evidence suggesting that the species diversity of water fleas is greater in northern regions than in the tropics.
This is a counterintuitive concept, as scientists have long supposed that the advance and readvance of ice sheets reduced much of the species diversity in colder climates, Taylor said. However, there is growing evidence that some northern areas remained ice-free and acted as hideouts during the harsh glacial advances.
The researchers not only convincingly documented new species diversity, but identified one likely new species and provided a detailed, formal description of another: Eurycercus beringi.
Like other water fleas, E. beringi is an important source of nutrients for fish and aquatic birds.
The new species -- from Alaska's remote Seward Peninsula -- has unusual anatomical features that force a rewrite of the taxonomy of Eurycercus above the species level. Moreover, the new anatomical details should aid future studies that use preserved body parts of Eurycercus found in lake sediments to reconstruct past ecological conditions.
The discovery of new crustacean species in unexpected places underscores the scope of the ongoing biodiversity crisis for freshwater ecosystems.
Read more at Science Daily