Sep 7, 2013

Scientists Use DNA to Assemble a Transistor from Graphene

Graphene is a sheet of carbon atoms arrayed in a honeycomb pattern, just a single atom thick. It could be a better semiconductor than silicon -- if we could fashion it into ribbons 20 to 50 atoms wide. Could DNA help?

DNA is the blueprint for life. Could it also become the template for making a new generation of computer chips based not on silicon, but on an experimental material known as graphene?

That's the theory behind a process that Stanford chemical engineering professor Zhenan Bao reveals in Nature Communications.

Bao and her co-authors, former post-doctoral fellows Anatoliy Sokolov and Fung Ling Yap, hope to solve a problem clouding the future of electronics: consumers expect silicon chips to continue getting smaller, faster and cheaper, but engineers fear that this virtuous cycle could grind to a halt.

Why has to do with how silicon chips work.

Everything starts with the notion of the semiconductor, a type of material that can be induced to either conduct or stop the flow of electricity. Silicon has long been the most popular semiconductor material used to make chips.

The basic working unit on a chip is the transistor. Transistors are tiny gates that switch electricity on or off, creating the zeroes and ones that run software.

To build more powerful chips, designers have done two things at the same time: they've shrunk transistors in size and also swung those gates open and shut faster and faster.

The net result of these actions has been to concentrate more electricity in a diminishing space. So far that has produced small, faster, cheaper chips. But at a certain point, heat and other forms of interference could disrupt the inner workings of silicon chips.

"We need a material that will let us build smaller transistors that operate faster using less power," Bao said.

Graphene has the physical and electrical properties to become a next-generation semiconductor material -- if researchers can figure out how to mass-produce it.

Graphene is a single layer of carbon atoms arranged in a honeycomb pattern. Visually it resembles chicken wire. Electrically this lattice of carbon atoms is an extremely efficient conductor.

Bao and other researchers believe that ribbons of graphene, laid side-by-side, could create semiconductor circuits. Given the material's tiny dimensions and favorable electrical properties, graphene nano ribbons could create very fast chips that run on very low power, she said.

"However, as one might imagine, making something that is only one atom thick and 20 to 50 atoms wide is a significant challenge," said co-author Sokolov.

To handle this challenge, the Stanford team came up with the idea of using DNA as an assembly mechanism.

Physically, DNA strands are long and thin, and exist in roughly the same dimensions as the graphene ribbons that researchers wanted to assemble.

Chemically, DNA molecules contain carbon atoms, the material that forms graphene.

The real trick is how Bao and her team put DNA's physical and chemical properties to work.

The researchers started with a tiny platter of silicon to provide a support (substrate) for their experimental transistor. They dipped the silicon platter into a solution of DNA derived from bacteria and used a known technique to comb the DNA strands into relatively straight lines.

Next, the DNA on the platter was exposed to a copper salt solution. The chemical properties of the solution allowed the copper ions to be absorbed into the DNA.

Next the platter was heated and bathed in methane gas, which contains carbon atoms. Once again chemical forces came into play to aid in the assembly process. The heat sparked a chemical reaction that freed some of the carbon atoms in the DNA and methane. These free carbon atoms quickly joined together to form stable honeycombs of graphene.

"The loose carbon atoms stayed close to where they broke free from the DNA strands, and so they formed ribbons that followed the structure of the DNA," Yap said.

So part one of the invention involved using DNA to assemble ribbons of carbon. But the researchers also wanted to show that these carbon ribbons could perform electronic tasks. So they made transistors on the ribbons.

"We demonstrated for the first time that you can use DNA to grow narrow ribbons and then make working transistors," Sokolov said.

The paper drew praise from UC Berkeley associate professor Ali Javey, an expert in the use of advanced materials and next-generation electronics.

"This technique is very unique and takes advantage of the use of DNA as an effective template for controlled growth of electronic materials," Javey said. "In this regard the project addresses an important research need for the field."

Bao said the assembly process needs a lot of refinement. For instance, not all of the carbon atoms formed honeycombed ribbons a single atom thick. In some places they bunched up in irregular patterns, leading the researchers to label the material graphitic instead of graphene.

Read more at Science Daily

Mother Chimps Crucial for Offspring's Social Skills

Orphaned chimpanzees are less socially competent than chimpanzees who were reared by their mother. Researchers from the Max Planck Institute for Psycholinguistics in Nijmegen, The Netherlands, observed that orphaned chimpanzees frequently engaged in social play, but their play bouts were much shorter and resulted in aggression more often. Apparently, chimpanzee mothers endow their offspring with important social skills.

It may not come as a surprise, but mother chimpanzees seem to be important for the development of social skills in young chimpanzees. "Orphaned chimpanzees had more difficulties to successfully coordinate their social play interactions," says Edwin van Leeuwen from the Comparative Cognitive Anthropology Research Group at the Max Planck Institute for Psycholinguistics. "Since social play comprises a complex context in which signals about intentions need to be communicated, it seems that orphaned chimpanzees have missed out on valuable lessons from their mothers."

Van Leeuwen and his co-authors Innocent Mulenga and Diana Lisensky compared the play behaviour of 8 orphaned and 9 mother-reared juvenile chimpanzees at the Chimfunshi Wildlife Orphanage Trust in Zambia. In this institution the orphan chimpanzees are initially cared for by humans. As soon as they are strong enough -- usually with one or two years of age -- they grow up in an orphan chimp group. "The chimps in the study were between four and nine years old, so they have kind of been raising each other," explains van Leeuwen. The orphaned and mother-reared chimpanzees matched in age and sex.

Based on previous research, the scientists expected the orphaned juveniles to play less frequently and smoothly than the mother-reared chimpanzees: After all, the orphans had missed their most important caretaker throughout a sensitive socialisation period, and continued to lack a safe and facilitating social environment provided by their mothers.

Contrary to their expectations, the orphaned chimpanzees engaged in social play more frequently than the mother-reared juveniles, although for shorter amounts of time. But social play of the orphaned juveniles resulted more often in aggression than social play of the young chimps that were reared by their mother. "Although the orphaned chimps were motivated to play," Van Leeuwen says, "it seems that they were less able to coordinate their play bouts and prevent them from resulting in aggression."

Read more at Science Daily

Sep 6, 2013

Monster Earth Volcano One of Solar System's Biggest

The largest volcano on Earth is not in Hawaii, but hidden beneath the western Pacific Ocean and covers an area the size of New Mexico, announced scientists on Thursday. The vast lump of lava is called the Tamu Massif and lies about 1,000 miles (1,600 km) east of Japan and is comparable, though somewhat less voluminous, than the enormous volcano Olympus Mons on Mars.

Tamu Massif itself is not a new discovery, but until now had been considered the product of several undersea volcanoes heaping and clumping up lava on the seafloor. New seismic reflection data showing the structures of the lava flows inside Tamu Massif, along with and specimens from the Integrated Ocean Drilling Program now suggest the entire, very low-relief, 120,000 square-mile (311,000 square kilometer) feature erupted from a single source. For instance, the seismic data show that some of the layers of lava -- representing single eruption events -- are 75 feet (23 meters) thick, spread out over huge distances.

"Think about that: it's huge," said William Sager of the University of Houston (until recently of Texas A&M University), lead author on a paper about the discovery which will be in the Sept. 8 issue of the journal Nature Geoscience.

By comparison, Mauna Loa on the Big Island of Hawaii, is just two percent of the area of Tamu Massif. Yet this is a volcano that can't even manage to show itself above the waves. Why?

One reason is that the lava is very low-viscosity, like that seen flowing at high speeds out of Kilauea in on the Big Island of Hawaii. And also like Kilauea, the lava flows probably formed cooled, hard, upper skins that then allowed the hotter lava to flow out underneath it. In Hawaii this sort of thing leaves behind lava tubes. On Tamu Massif, which must have had vastly more lava erupting than Kilauea, it allows the flow to spread out over a huge area of the seafloor -- like a gigantic pile of spilled glue. In fact, the slopes of Tamu Massif are so subtle, say the researchers, that if you could stand on them and look around, you'd have a hard time deciding which way was uphill.

Another possible reason for why Tamu Massif lies so low is the crust on which it formed.

"Tamu Massif is 4 kilometers high, but 30 kilometers thick," Sager explained. That's probably because the magma that erupted was very high density, heavy stuff that pressed down the thin, weak oceanic crust onto which it erupted between 130 to 145 million years ago and pushed the crust lower -- sort of like piling bricks on a thin, soft mattress. In contrast, the eruptions of the five volcanoes that created the Big Island of Hawaii piled up lava on thicker, sturdier crust, or lithosphere, (a thicker, firmer mattress) which could perhaps bear the weight better, he explained. Mars' giant volcano is at the far end of the spectrum from Tamu Massif.

"Olympus Mons is on very thick lithosphere," said Sager. Which is why it is so it reaches the edge of space.

Read more at Discovery News

Rare Fossil Ape Cranium Discovered in China

A team of researchers has discovered the cranium of a fossil ape from Shuitangba, a Miocene site in Yunnan Province, China. The juvenile cranium of the fossil ape Lufengpithecus is significant, according to team member Nina Jablonski, Distinguished Professor of Anthropology at Penn State.

Jablonski noted that juvenile crania of apes and hominins are extremely rare in the fossil record, especially those of infants and young juveniles. This cranium is only the second relatively complete cranium of a young juvenile in the entire Miocene -- 23-25 million years ago -- record of fossil apes throughout the Old World, and both were discovered from the late Miocene of Yunnan Province.

The cranium is also noteworthy for its age. Shuitangba, the site from which it was recovered, at just over 6 million years old, dates to near the end of the Miocene, a time when apes had become extinct in most of Eurasia. Shuitangba has also produced remains of the fossil monkey, Mesopithecus, which represents the earliest occurrence of monkeys in East Asia.

Jablonski was co-author of a recent paper online in the Chinese Science Bulletin that described the discovery.

"The preservation of the new cranium is excellent, with only minimal post-depositional distortion," Jablonski said. "This is important because all previously discovered adult crania of the species to which it is assigned, Lufengpithecus lufengensis, were badly crushed and distorted during the fossilization process. In living ape species, cranial anatomy in individuals at the same stage of development as the new fossil cranium already show a close resemblance to those of adults."

Therefore, the new cranium, despite being from a juvenile, gives researchers the best look at the cranial anatomy of Lufengpithecus lufengensis.

"Partly because of where and when Lufengpithecus lived, it is considered by most to be in the lineage of the extant orangutan, now confined to Southeast Asia but known from the late Pleistocene of southern China as well," Jablonski said.

However, the researchers noted the cranium shows little resemblance to those of living orangutans, and in particular, shows none of what are considered to be key diagnostic features of orangutan crania. Lufengpithecus therefore appears to represent a late surviving lineage of Eurasian apes, but with no certain affinities yet clear.

Read more at Science Daily

Indiana Jones Meets George Jetson

A team of researchers from Uppsala University in Sweden has designed a microplasma source capable of exciting matter in a controlled, efficient way. This miniature device may find use in a wide range of applications in harsh environments, but can also help revolutionize archaeology.

As the researchers describe in the Journal of Applied Physics, produced by AIP Publishing, their new device offers many advantages, such as electromagnetic compatibility, an integrated fluidic system, and Langmuir probes for plasma diagnostics.

At the university's Ångström Space Technology Centre (ÅSTC), the researchers work with many kinds of micro and nanotechnologies for use in space and other harsh environments: scientific instruments, imaging, communication hardware, vehicles and spacecraft, propulsion devices, and thermal management. Size limitation is always a huge challenge.

"Putting miniaturized hardware into orbit or thousands of meters underground is always technically easier and less expensive, but using fundamentally different technology for demanding applications is often met with skepticism," explains Greger Thornell, director of ÅSTC. "So we need to also compete in terms of performance and reliability."

The researchers are accustomed to working with microrocketry and localized phenomena in tiny devices such as sensors and actuators. These types of phenomena sometimes involve very high temperatures, intense plasma, and high pressures.

"In this case, the localization, or rather concentration, means that the device itself becomes handy and power-efficient, and also that it consumes small sample amounts, which widens the range of applications far beyond the requirement of simply lightweight or portable instruments," said Thornell.

Archaeology is one of the main applications being investigated right now to help determine the distribution of carbon isotopes in organic samples. "This information is critical for archaeologists, but measuring these isotope distributions can be extremely painstaking and time consuming," said Anders Persson, senior researcher.

Their plasma source may be used to develop an instrument for field archaeologists, which would allow them to perform measurements while out in the field; this in turn may revolutionize archaeology by diversifying the amount of information available during the decision-making process of an excavation. "Archaeology is just one of the many exciting applications we see for our plasma source," he added.

Read more at Science Daily

TB Migrated Out of Africa With Humans

The bacteria that cause tuberculosis emerged at least 70,000 years ago and followed humans out of Africa, suggests new research.

From there, TB tagged along on human migrations and evolved as people changed. The new findings offer insight into a disease that kills as many as 2 million people every year and is increasingly developing resistance to drugs designed to treat it.

“The evolutionary path of humans and the TB bacteria shows striking similarities,” said Sebastien Gagneux from the Swiss Tropical and Public Health Institute in a press release. “We see that the diversity of tuberculosis bacteria has increased markedly when human populations expanded.”

Between the 17th and 19th centuries, TB killed 20 percent of adults in Europe and North America. Even today, it remains one of the deadliest infectious diseases in humans, particularly in developing countries. When untreated, it kills half of all people it infects.

To better understand the history of TB, Gagneux and colleagues sequenced and compared the genomes of 259 strains of the M. tuberculosis bacteria from around the world. Then they reconstructed a TB family tree, which allowed them to trace back the origins of the disease to somewhere in Africa about 70,000 years ago.

When the researchers compared the TB family tree with the history of human migrations, they reported in the journal Nature Genetics, they found remarkable similarities. The disease split into branches at the same time that waves of hunter-gatherers left Africa and moved into Europe and Asia.

A boom in human population around 10,000 years ago also coincided with the expansion of TB, probably because denser groups of people allowed the disease to spread more easily.

Read more at Discovery News

Sep 5, 2013

Beneath Earth's Surface, Scientists Find Long 'Fingers' of Heat

Scientists seeking to understand the forces at work beneath the surface of Earth have used seismic waves to detect previously unknown "fingers" of heat, some of them thousands of miles long, in Earth's upper mantle. Their discovery, published Sept. 5 in Science Express, helps explain the "hotspot volcanoes" that give birth to island chains such as Hawai'i and Tahiti.

Many volcanoes arise at collision zones between the tectonic plates, but hotspot volcanoes form in the middle of the plates. Geologists have hypothesized that upwellings of hot, buoyant rock rise as plumes from deep within Earth's mantle -- the layer between the crust and the core that makes up most of Earth's volume -- and supply the heat that feeds these mid-plate volcanoes.

But some hotspot volcano chains are not easily explained by this simple model, a fact which suggests there are more complex interactions between these hot plumes and the upper mantle. Now, a computer modeling approach, developed by University of Maryland seismologist Vedran Lekic and colleagues at the University of California Berkeley, has produced new seismic wave imagery which reveals that the rising plumes are, in fact, influenced by a pattern of finger-like structures carrying heat deep beneath Earth's oceanic plates.

Seismic waves are waves of energy produced by earthquakes, explosions and volcanic eruptions, which can travel long distances below Earth's surface. As they travel through layers of different density and elasticity, their shape changes. A global network of seismographs records these changing waveforms. By comparing the waveforms from hundreds of earthquakes recorded at locations around the world, scientists can make inferences about the structures through which the seismic waves have traveled.

The process, known as seismic tomography, works in much the same way that CT scans (computed tomography) reveal structures hidden beneath the surface of the human body. But since we know much less about the structures below Earth's surface, seismic tomography isn't easy to interpret. "The Earth's crust varies a lot, and being able to represent that variation is difficult, much less the structure deeper below" said Lekic, an assistant professor of geology at the College Park campus.

Until recently, analyses like the one in the study would have taken up to 19 years of computer time. While studying for his doctorate with the study's senior author, UC Berkeley Prof. Barbara Romanowicz, Lekic developed a method to more accurately model waveform data while still keeping computer time manageable, which resulted in higher-resolution images of the interaction between the layers of Earth's mantle.

By refining this method, a research team led by UC Berkeley graduate student Scott French found finger-like channels of low-speed seismic waves flowing about 120 to 220 miles below the sea floor, and stretching out in bands about 700 miles wide and 1,400 miles apart. The researchers also discovered a subtle but important difference in speed: at this depth, seismic waves typically travel about 2.5 to 3 miles per second, but the average seismic velocity in the channels was 4 percent slower. Because higher temperatures slow down seismic waves, the researchers infer that the channels are hotter than the surrounding material.

"We estimate that the slowdown we're seeing could represent a temperature increase of up to 200 degrees Celsius," or about 390 degrees Fahrenheit, said French, the study's study lead author. At these depths, absolute temperatures in the mantle are about 1,300 degrees Celsius, or 2,400 degrees Fahrenheit, the researchers said.

Geophysicists have long theorized that channels akin to those revealed in the computer model exist, and are interacting with the plumes in Earth's mantle that feed hotspot volcanoes. But the new images reveal for the first time the extent, depth and shape of these channels. And they also show that the fingers align with the motion of the overlying tectonic plate. The researchers hypothesize that these channels may be interacting in complex ways with both the tectonic plates above them and the hot plumes rising from below.

Read more at Science Daily

Toxic Gas First Used in Syria 1,700 Years Ago

If Syrian President Bashar al-Assad has really carried out a chemical attack, it wouldn’t be the first time poisonous gas brought death in the Middle East country.

Indeed, right in Syria archaeologists have found some of the oldest evidence of chemical warfare.

According to University of Leicester archaeologist Simon James, who published his findings back in 2009, poison gas was used in Syria more than 1,700 years ago when a Roman fort at Dura-Europos became the site of a violent siege by the powerful Sasanian Persian empire.

No historical record exists of the battle, which occurred around 256 A.D., but archaeological remains, unearthed by major excavations in 1920-1937 by teams from France and Yale University, and after 1986 by French-Syrian teams, helped James piece together the action.

Trying to enter the city, the Sasanians dug tunnels underneath its walls. Intending to hold their ground at all costs, Roman defenders responded with counter-mines.

In the 1930s, archaeologists unearthed dramatic evidence of the fight. In one of the tunnels, a pile of bodies, still completely fitted with their weapons and armour, testified to the horrors of the battle.

At the time, the researchers believed the trapped Roman soldiers had died after the tunnel collapsed. But according to James, residue of pitch (a resinous substance) and yellow sulfur crystals found in a jar lying near the bodies indicated a much more gruesome reality.

Indeed, the Sasanians placed fire pits strategically throughout the tunnel, and when the Romans broke through, they gassed them by adding sulfur crystals and bitumen to the fire.

“Defining what constitutes a chemical weapon in antiquity is complex, but this is certainly one of the earliest archaeological finds of the addition of chemical accelerants to a fire to produce toxic fumes,” Adrienne Mayor, a research scholar in classics and history of science at Stanford University, told Discovery News.

Mayor described the skirmish in the tunnel and the presence of burnt residue as an early example of archaeological evidence for a chemical incendiary in her 2003 book “Greek Fire, Poison, Arrows and Scorpion Bombs.”

According to the scholar, a possible contender for the earliest archaeological evidence for a chemical weapon is a charred, manmade fire ball from the archaeological battle site at Gandhara, Pakistan.

“The burning missile had been hurled at Alexander’s besieging army in 327 BC. Chemical analysis revealed the ball’s composition included sulfur, barite, and pitch,” Mayor said.

The ball was certainly ignited in a fire, but whether this was deliberate or accidental is impossible to establish.

Long before World War I, when 39 different toxic agents — ranging from simple tear gas to mustard gas — were extensively used, it was a mixture of sulfur and pitch that gassed enemies.

Greek historian and Athenian general Thucydides described how, during the Peloponnesian War, the Spartans created a sulfur and pitch (in this case pine resin) fire at the siege of Plateia, Greece, in 429 BC.

The Boeotians, Sparta’s allies, used a similar chemical flame-thrower in 424 BC at Delium, combining burning coal, sulfur and pitch.

Read more at Discovery News

Witch Doctors' Animal Sacrifices Pollute Water Supply

Witch doctors regularly dump animal sacrifices into the reservoir meant to quench the thirst, clean the dishes and wash the clothes of 750,000 Venezuelans, reported Bloomberg. As a result, citizens of one of the most dangerous, crime-ridden cities in the world, Caracas, Venezuela, can’t even take a drink of water from the tap safely.

The 60-year old water treatment plant at the reservoir lacks the ability to filter out the toxins from the putrefying carcasses. Because of this, Caracas resisdents are now paying 30 Bolivars ($4.80) for a five-gallon jug of water. Gasoline only costs 14 Bolivars, due to generous government subsidies.

The water supply of Caracas seems cursed. Practitioners of Santeria sacrifice animals and dump their bodies with impunity into the reservoir.

“No one is bothering me here at all,” local Santeria practitioner Francisco Sanchez told Bloomberg.

Santeria is a hybrid, or syncretic, religion that sprang from the animistic beliefs of West African slaves blended with the Catholicism of their Spanish captors, mixed with the surviving remnants of indigenous people’s religions.

Although Santeria brings spiritual solace to thousands, in Venezuela, Santeria witch doctors dumping animal sacrifices into reservoirs mostly just increases the suffering of others, especially the poorest members of society.

In many regions of the developing world, people who drink water from the tap run the risk of bacterial infection or contamination from agricultural run-off and other pollutants. Many people spend a significant portion of their income on purified water to avoid the even greater cost of debilitating illness.

People who can’t afford bottled water have to find other ways of reducing their risks. For example in Honduras, people often use discarded soda bottles filled with tap water then placed those bottles in direct sun for a few days. The UV radiation from the sun kills off many pathogens, however it fails to filter out contaminants, such as animal feces.

Read more at Discovery News

Mystery Mummy Found in German Attic

German police, prosecutors and forensics experts are facing a mystery after a 10-year-old boy found a human mummy in a sarcophagus in a corner of his grandparents' attic.

A CT scan has revealed a well-preserved human skull, with an arrow sticking out of the left eye socket, and large parts of a skeleton with the arms crossed over the chest, the local newspaper Kreiszeitung has reported.

Adding to the riddle is a death mask also found in the box, and the fact that X-rays show a metal layer covering the bones of the 1.49-meter-long (4 feet 8 inches) human remains of unknown gender.

The boy's father, Lutz-Wolfgang Kettler, said his own father, who died 12 years ago, had in the 1950s travelled to North Africa and may have brought back the mummy as a grisly souvenir.

The bandages used for the mummy -- which has not been unwrapped for fear of damaging the remains -- date from the 20th century and are machine-woven, said Kettler, a dentist who attended the CT scan.

Pathologist Andreas Nerlich of Munich's Bogenhausen hospital told news website Spiegel Online that, while the skull and the bones are real, the mummy is "a fake, made from one or several human bodies."

Read more at Discovery News

Sep 4, 2013

New Low-Temperature Chemical Reaction Explained

In all the centuries that humans have studied chemical reactions, just 36 basic types of reactions have been found. Now, thanks to the work of researchers at MIT and the University of Minnesota, a 37th type of reaction can be added to the list.

The newly explained reaction -- whose basic outlines had been known for three decades, but whose workings had never been understood in detail -- is an important part of atmospheric reactions that lead to the formation of climate-affecting aerosols; biochemical reactions that may be important for human physiology; and combustion reactions in engines.

The new analysis is explained in a paper by MIT graduate student Amrit Jalan, chemical engineering professor William Green, and six other researchers, published in the Journal of the American Chemical Society.

Stephen Klippenstein, a senior scientist at the Argonne National Laboratory in Illinois who was not involved in this research, says, "I think this may be the best paper I have read this year. It uses a multitude of theoretical methods … to explore multiple aspects of a novel discovery that has important ramifications in atmospheric chemistry, combustion kinetics and biology."

The reaction's details sound esoteric: a low-temperature oxidation that results in the decomposition of complex organic molecules known as gamma-ketohydroperoxides. When he first described the reaction in the scientific literature 30 years ago, Stefan Korcek of the Ford Motor Company proposed a hypothesis for how the reaction might take place. The new work shows that Korcek had the right concept, although some details differ from his predictions.

The original discovery was the result of analyzing how engine oils break down through oxidation -- part of an attempt to produce oils that would last longer. That's important, Green points out, since waste oil is among the largest hazardous waste streams in the United States.

In analyzing the problem, Korcek realized that "there were fundamental things about the way even simple hydrocarbons react with oxygen that we didn't understand," Green says. By examining the products of the reaction, which included carboxylic acids and ketones, Korcek outlined an unusually complex multipart reaction. But for the next three decades, nobody found a way to verify whether the reaction or the steps he outlined could work.

Jalan says that the MIT researchers' analysis came about almost by accident. "I was looking at that paper for a different study," he says, "and I came across [Korcek's] work, which hadn't been verified either theoretically or experimentally. … [We] decided to see if we could explain his observations by throwing quantum mechanical tools at the problem."

In collaboration with the Minnesota researchers -- including Donald Truhlar, a co-author of the new paper and a leading expert in such calculations -- Jalan and Green were able to demonstrate exactly why the reaction works as it does. But they also found that part of the process must differ slightly from Korcek's original hypothesis.

Green says that understanding how this "very important reaction" works could be significant in several fields. The researchers' initial impetus was, in part, a colleague's exploration of biofuel combustion. The new understanding of the degradation that can take place as different fuels oxidize -- sometimes producing toxic or corrosive byproducts -- could help narrow the choice of fuel types to pursue, he says.

The process is also related to oxidations that take place in the body, contributing to the tissue damage and aging that antioxidant vitamins seek to combat, Green says.

Green points out that because this is an entirely new type of reaction, it opens the door to research on other variations. "Once you discover a new type of reaction, there must be many similar ones," he says.

"It's very odd to have so many reactions at once in such a small molecule," Green adds. "Now that we know that can happen, we're searching for other cases."

Anthony Dean, dean of the College of Applied Science and Engineering at the Colorado School of Mines, who was not involved in this work, says, "A particularly nice aspect of this work is to then consider how this finding might be applicable to other systems. In a broader context, this combined effort by two very prominent research groups illustrates the power and potential for electronic structure calculations [in] quantitatively important problems in chemical kinetics."

Read more at Science Daily

West Antarctica Ice Sheet Existed 20 Million Years Earlier Than Previously Thought

The results of research conducted by professors at UC Santa Barbara and colleagues mark the beginning of a new paradigm for our understanding of the history of Earth's great global ice sheets. The research shows that, contrary to the popularly held scientific view, an ice sheet on West Antarctica existed 20 million years earlier than previously thought.

The findings indicate that ice sheets first grew on the West Antarctic subcontinent at the start of a global transition from warm greenhouse conditions to a cool icehouse climate 34 million years ago. Previous computer simulations were unable to produce the amount of ice that geological records suggest existed at that time because neighboring East Antarctica alone could not support it.

The findings were published today in Geophysical Research Letters, a journal of the American Geophysical Union.

Given that more ice grew than could be hosted only on East Antarctica, some researchers proposed that the missing ice formed in the northern hemisphere, many millions of years before the documented ice growth in that hemisphere, which started about 3 million years ago. But the new research shows it is not necessary to have ice hosted in the northern polar regions at the start of greenhouse-icehouse transition.

Earlier research published in 2009 and 2012 by the same team showed that West Antarctica bedrock was much higher in elevation at the time of the global climate transition than it is today, with much of its land above sea level. The belief that West Antarctic elevations had always been low lying (as they are today) led researchers to ignore it in past studies. The new research presents compelling evidence that this higher land mass enabled a large ice sheet to be hosted earlier than previously realized, despite a warmer ocean in the past.

"Our new model identifies West Antarctica as the site needed for the accumulation of the extra ice on Earth at that time," said lead author Douglas S. Wilson, a research geophysicist in UCSB's Department of Earth Science and Marine Science Institute. "We find that the West Antarctic Ice Sheet first appeared earlier than the previously accepted timing of its initiation sometime in the Miocene, about 14 million years ago. In fact, our model shows it appeared at the same time as the massive East Antarctic Ice Sheet some 20 million years earlier."

Wilson and his team used a sophisticated numerical ice sheet model to support this view. Using their new bedrock elevation map for the Antarctic continent, the researchers created a computer simulation of the initiation of the Antarctic ice sheets. Unlike previous computer simulations of Antarctic glaciation, this research found the nascent Antarctic ice sheet included substantial ice on the subcontinent of West Antarctica. The modern West Antarctic Ice Sheet contains about 10 percent of the total ice on Antarctica and is similar in scale to the Greenland Ice Sheet.

West Antarctica and Greenland are both major players in scenarios of sea level rise due to global warming because of the sensitivity of the ice sheets on these subcontinents. Recent scientific estimates conclude that global sea level would rise an average of 11 feet should the West Antarctic Ice Sheet melt. This amount would add to sea level rise from the melting of the Greenland ice sheet (about 24 feet).

The UCSB researchers computed a range of ice sheets that consider the uncertainty in the topographic reconstructions, all of which show ice growth on East and West Antarctica 34 million years ago. A surprising result is that the total volume of ice on East and West Antarctica at that time could be more than 1.4 times greater than previously realized and was likely larger than the ice sheet on Antarctica today.

Read more at Science Daily

Mysterious Amazon Web Tower Baffles Scientists

A bizarre-looking web structure has been found in the Peruvian Amazon, and apparently nobody knows what it is, not even scientists.

The strange formation resembles a tiny spire surrounded by a webby picket fence and is about 2 centimeters (0.8 inches) wide. Georgia Tech graduate student Troy Alexander first spotted one of these on the underside of a tarp near the Tambopata Research Center in the Peruvian Amazon. At first he thought it might have been an aborted moth cocoon, he wrote on Reddit. But then he found several more, all of which looked quite similar.

He posted the photos to Reddit and asked other scientists to help him out, besides making queries around the Tambopata Research Center, to no avail. His guess is that "there are eggs in the base of the maypole in the middle of the horse corral, though it might be something pupating," he wrote on Reddit.

Chris Buddle, an arachnologist at McGill University, said that neither he nor any of his associates know what it is. "I have no clue," he said. It's "a seriously fascinating mystery."

"I have no idea what animal made that," Norman Platnick, curator emeritus of spiders at the American Museum of Natural History in New York, told LiveScience.

So far, Redditors and others have guessed that it could be some kind of moth cocoon, an intricate defense for spider eggs, or even the fruiting body of some type of fungus.

Alexander fell in love with the Peruvian Amazon while on vacation there, he told Colossal, an art blog. So he asked his adviser if he could take a leave of absence to be a volunteer researcher. Shortly thereafter, Alexander flew back to Peru to work at the Tambopata Macaw Project, which focuses on parrot biology and conservation, he told Colossal.

Read more at Discovery News

Mystery Alignment of 'Butterfly' Nebulae Discovered

Astronomers have discovered something weird in the Milky Way's galactic bulge -- a population of planetary nebula are all mysteriously pointing in the same direction.

While using the Hubble Space Telescope and the European Southern Observatory's New Technology Telescope (NTT) to survey 130 planetary nebulae situated near the hub of our galaxy, astronomers from the University of Manchester sorted them into three populations based on their shape: "elliptical," "either with or without an aligned internal structure" and "bipolar."

They noticed the mysterious alignment in the long axes of bipolar planetary nebulae.

Planetary nebulae are caused by the death of red giant stars. During their final years, long after the hydrogen fuel has run out in their cores, these puffed up stars begin to shed their outer layers, blasting huge quantities of material into space. At the end of its life the sun will also enter into a red giant phase, swallowing up the inner solar system planets (possibly even Earth), eventually creating its own planetary nebula.

The resulting nebulous clouds can take on many beautiful shapes, but bipolar planetary nebulae can be the most striking, generating two lobes of material expanding in opposite directions. These nebulae often resemble butterfly wings.

Although the surveyed nebulae are completely separate, non-interacting and are of various ages, the researchers noticed a large number of the nebulae long axes are aligned.

"This really is a surprising find and, if it holds true, a very important one," said Bryan Rees of the University of Manchester, co-author of the paper to appear in the journal Monthly Notices of the Royal Astronomical Society. "Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy. By using images from both Hubble and the NTT we could get a really good view of these objects, so we could study them in great detail."

The other two populations of planetary nebulae appear to be randomly oriented in relation to the galactic disk.

"While any alignment at all is a surprise, to have it in the crowded central region of the galaxy is even more unexpected," said the paper's second author Albert Zijlstra, also of the University of Manchester, in Wednesday's Hubble press release.

So what could be causing this strange alignment inside the galactic bulge?

The shapes of planetary nebulae are thought to be caused by factors such as the orientation of its system before the star turned into a red giant, or whether the star was part of a binary pair. But as for a common alignment across an apparently independent selection of nebulae, some external factor appears to be having a strong influence.

"The alignment we're seeing for these bipolar nebulae indicates something bizarre about star systems within the central bulge," said Rees. "For them to line up in the way we see, the star systems that formed these nebulae would have to be rotating perpendicular to the interstellar clouds from which they formed, which is very strange."

Interestingly, bipolar planetary nebulae do not appear to have a preferential orientation in our galactic neighborhood many thousands of light-years from the galactic core. The alignment effect only seems to act near the center of the Milky Way.

Read more at Discovery News

Sep 3, 2013

Celestial Treats Hide Inside the Summer Triangle

The Summer Triangle is one of the most easily recognized groups of stars in Northern Hemisphere skies.

The Triangle is depicted by the brightest stars of the constellations Cygnus, Lyra and Aquila, and dominates the sky during the warmer months of summer. Within its boundaries, there are some great celestial objects for the novice astronomer -- not only are they bright, but they really pack a punch through the eyepiece so they are well worth hunting down.

The star Vega marks the north-west corner of the Summer Triangle and is the brightest star in the constellation Lyra. If you look to the south-east of Vega you will be able to see a fainter parallelogram of stars and, if you turn even a small telescope between the two southernmost stars, you will find a faint fuzzy blob.

This inconspicuous object is a star that has reached the end of its life and leaves our night sky with a beautiful planetary nebula. It is known as the Ring Nebula, or M57, and as its name suggests, it looks like a stunning celestial smoke ring hovering against the inky black depths of space. Even a small telescope will show respectable views.

Deneb represents the north-east corner of the Triangle and, at the same time, marks the tail of Cygnus the swan. The star at the head of the swan sits at the very center of the Summer Triangle and is known as Albireo. Through small telescopes this stunning binary star resolves into yellow and blue individual stars.

Just under half-way between Altair (the star at the southern tip of the Triangle) and Sadr, the star at the center of the cross in the constellation of Cygnus is another planetary nebula, but one whose appearance differs significantly from the Ring Nebula.

M27, or the Dumbbell Nebula, can just about be detected with binoculars as a fuzzy patch, but telescopes with low to medium power will reveal a fuzzy blob that resembles a dumbbell or bow tie. As aperture is increased, the nebula appears brighter due to the greater amount of light being collected and under dark skies, subtle detail can be seen in the cloud.

Read more at Discovery News

Language and Tool-Making Skills Evolved at the Same Time

Research by the University of Liverpool has found that the same brain activity is used for language production and making complex tools, supporting the theory that they evolved at the same time.

Researchers from the University tested the brain activity of 10 expert stone tool makers (flint knappers) as they undertook a stone tool-making task and a standard language test.

Brain blood flow activity measured

They measured the brain blood flow activity of the participants as they performed both tasks using functional Transcranial Doppler Ultrasound (fTCD), commonly used in clinical settings to test patients' language functions after brain damage or before surgery.

The researchers found that brain patterns for both tasks correlated, suggesting that they both use the same area of the brain. Language and stone tool-making are considered to be unique features of humankind that evolved over millions of years.

Darwin was the first to suggest that tool-use and language may have co-evolved, because they both depend on complex planning and the coordination of actions but until now there has been little evidence to support this.

Dr Georg Meyer, from the University Department of Experimental Psychology, said: "This is the first study of the brain to compare complex stone tool-making directly with language.

Tool use and language co-evolved

"Our study found correlated blood-flow patterns in the first 10 seconds of undertaking both tasks. This suggests that both tasks depend on common brain areas and is consistent with theories that tool-use and language co-evolved and share common processing networks in the brain."

Dr Natalie Uomini from the University's Department of Archaeology, Classics & Egyptology, said: "Nobody has been able to measure brain activity in real time while making a stone tool. This is a first for both archaeology and psychology."

Read more at Science Daily

Weird! Tiny Frog Uses Its Mouth to Hear

A small frog native to the Republic of Seychelles lacks a conventional middle ear and eardrum to hear sounds made by other frogs, but new research suggests these peculiar croakers are not deaf, and can instead use their mouth cavities to pick up on noise.

Gardiner's frogs from the Seychelles islands are one of the smallest known types of frogs in the world. These amphibians are seemingly deaf -- having no middle ear or eardrum to help process sound waves -- but can mysteriously still make their own croaking sounds, and hear the calls of other frogs. In a new study, researchers used X-ray imaging to peer inside the frogs' heads, finding they use their mouth cavities to amplify sounds that travel to the inner ear through connective tissue.

Most four-legged animals have middle ears that contain small, bony ossicles that take vibrations from the eardrum and transmit the sound waves from the air to the fluid-filled cochlea.

"However, we know of frog species that croak like other frogs but do not have tympanic middle ears to listen to each other. This seems to be a contradiction," lead study researcher Renaud Boistel, of the French National Center for Scientific Research (Centre National de la Recherche Scientifiqueor CNRS) in Paris, France, said in a statement.

To determine that Gardiner's frogs do, in fact, use sound to communicate with one another, the scientists set up loudspeakers in the natural rain forests of Seychelles and played pre-recorded frog songs. Males in the rain forests promptly answered the songs, signifying they could hear the recording, the researchers said.

Several ideas had been suggested for how the Gardiner's frogs could hear sounds, including extra auditory pathways through the lungs or special muscles in the frogs that connect to the inner ear.

"Whether body tissue will transport sound or not depends on its biomechanical properties," study co-author Peter Cloetens, a scientist at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, said in a statement. "With X-ray imaging techniques here at ESRF, we could establish that neither the pulmonary system nor the muscles of these frogs contribute significantly to the transmission of sound to the inner ears."

By studying X-ray images and numerical simulations, the researchers discovered that Gardiner's frogs receive sound through their heads. The mouth amplifies the frequencies and the sound is transmitted through tissue and bones in the skull to the inner ear.

The X-ray images showed reduced thickness and fewer layers of tissue between the frogs' mouths and their inner ears, compared with other frog species, which suggests these auditory adaptations were likely the result of evolutionary forces in Gardiner's frogs, the researchers said.

Read more at Discovery News

America's Invasive Species 450 Million Years Ago

The rise of the forerunners of the Appalachian Mountains may have opened the gates for invasive species to storm the lost continent that gave rise to North America, new research suggests.

Such research could shed light on how to prevent the modern spread of invasive species, the scientists who studied the issue said.

Scientists investigated 450-million-year-old fossils of marine creatures that once dwelled in Laurentia, the continent North America once was part of. At that time, Laurentia straddled the equator and had a tropical climate.

Shifting of the Earth's tectonic plates during this period gave rise to the Taconic Mountains, forerunners of today's Appalachian Mountains. This left a depression behind the mountain range, flooding the area with cool, nutrient-rich water from the surrounding deep ocean into Laurentia's inland seas.

To learn more about the effects of this mountain-building and cooling water on the evolution of life in this area, researchers investigated the remains of clamlike animals known as brachiopods that dominated Laurentian seas. By analyzing subtle features of 53 species of these fossils, they deduced the family trees of evolutionary relationships linking these creatures to discern how these species evolved from one another.

"Our data show a very clear shift in evolutionary processes that coincides with a shift in Earth systems dynamics," researcher Alycia Stigall, a paleontologist at Ohio University, told LiveScience." In particular, these results shed light on the Earth system controls on how new species form, or speciation."

Invading species

As geological changes slowly unfolded in Laurentia over the course of a million years, the fossils suggest two patterns of survival emerged among the creatures there.

During the early stage of the changes, native organisms became geographically divided, slowly evolving into different species suited for their different habitats. This process, called vicariance, is the typical method by which new species develop on Earth, Stigall said.

However, as these geological changes progressed, species from other regions of Laurentia began to directly invade habitats, a process called dispersal. Although biodiversity increased at first, dispersal reduced biodiversity in the long term, because it permitted a few aggressive species to populate and dominate many sites quickly, Stigall explained.

These findings could yield insights into what drives the dispersal of invasive species, which is currently threatening biodiversity worldwide.

"Only one out of 10 invaders truly become invasive species," Stigall said in a statement. "Understanding the process can help determine where to put conservation resources."

How Earth makes and destroys species

Overall, such research could help shed light on how changes Earth undergoes in turn drives the destruction and creation of new species.

"Scientists, both biologists and paleontologists, have spent a lot of time and effort studying extinction — the process by which the Earth loses species," Stigall said. "We understand many of those controls very well — (meteor) impact, volcanism, ocean acidification, habitat destruction. It is relatively easy to envision ways to reduce a population size to zero and thereby cause a species to go extinct."

"Understanding speciation is much more complex," Stigall continued. "Species form by breakdown of gene flow between populations. This is much harder to study on short timescales and the process is explicitly tied to a geographic place and ancestors, which requires understanding both geography and evolutionary history."

Read more at Discovery News

Sep 2, 2013

Quitting Smoking Drops Heart Attack Risk to Levels of Never Smokers

Quitting smoking reduces the risk of heart attack and death to the levels of people who have never smoked, reveals research presented at ESC Congress 2013 by Dr James K. Min and Dr Rine Nakanishi from the USA.

Dr Min said: "Smoking is an established risk factor for cardiovascular disease. Studies have identified that quitting smoking can reduce heart attacks and death but have not examined the relationship of this salutary effect on the presence and severity of coronary artery disease (CAD). Our study aimed to find out what impact stopping smoking had on the risk of cardiovascular events, death and the severity of CAD." The prospective CONFIRM (Coronary CT Evaluation for Clinical Outcomes: An International Multicenter Study) registry of 13,372 patients from 9 countries in Europe, North America and East Asia examined the risk of major adverse cardiac events in 2,853 active smokers, 3,175 past smokers and 7,344 never smokers.

Both active smokers and past smokers had a higher prevalence of severely blocked coronary arteries compared to non-smokers. This was determined using coronary computed tomographic angiography (CCTA), a non-invasive imaging technique that enables direct visualisation of the coronary arteries. Active and past smokers had a 1.5-fold higher probability of severe stenoses in 1 and 2 major heart arteries, and a 2-fold increased probability of severe stenoses in all 3 major heart arteries.

Dr Min, who is director of the Institute of Cardiovascular Imaging at the New York-Presbyterian Hospital and the Weill Cornell Medical College, said: "Our results show that quitting smoking does not reduce the amount of disease smoking causes in the coronary arteries, but it does reduce the risk of heart attack and death to the levels of non-smokers." After 2.0 years of follow-up, 2.1% of the study patients experienced heart attacks or death. Rates of heart attack or death were almost 2-fold higher in active smokers compared to never smokers. Past smokers had the same rates or heart attack or death as never smokers, despite having a higher prevalence, extent and severity of CAD (see figure). The findings in both active and past smokers persisted even when they were matched with non smokers who were similar in age, gender and CAD risk factors.

Dr Min said: "Our study was the first to demonstrate that the presence and severity of coronary blockages do not go away with quitting smoking, but that the risk of heart attack and death does. Future studies are being pursued to determine how this protective effect may occur."

He continued: "Numerous questions remain and require further study. For example, will the severe blockages observed in patients who have quit smoking provoke adverse events after 2 years (the duration of the present study). Further, does the duration of smoking or the number of cigarettes smoked per day affect the severity of CAD or the prognosis related to quitting smoking. Our team and several others are pursuing such investigations."

Read more at Science Daily

Evidence of Production of Luxury Textiles and the Extraction of Copper from an Unknown Part of a Cypriote Bronze Age City

A Swedish archaeological expedition from the University of Gothenburg has excavated a previously unknown part of the Bronze Age city Hala Sultan Tekke (around 1600-1100 BC). The finds include a facility for extraction of copper and production of bronze objects, evidence of production of luxurious textiles, as well as ceramics and other objects imported from all over the Mediterranean but also from central Europe.

'One of our conclusions is that the Bronze Age culture in Hala Sultan Tekke played a central role in the Eastern Mediterranean. Cyprus served as an important node not only for regional but also for more long-distance trade. We have also realized that the city was larger than previously thought,' says Peter Fischer, professor of Cypriote archaeology at the University of Gothenburg.

Hala Sultan Tekke is located near the Larnaca airport on the Mediterranean island of Cyprus and spans approximately 25-50 hectares, making it one of the largest Bronze Age cities in the Mediterranean region. In 2010, Peter Fischer and his team of archaeologists and students continued the excavations of the city that were initiated in the 1970s by Fischer's former teacher, professor Paul Åström.

The recently excavated part of the city was discovered in 2012 using a ground penetrating radar, which is an electromagnetic equipment that makes it possible to 'see' what's hidden in the ground down to a depth of about two metres. The method also enables archaeologists to get a tomographic image of a limited area under the surface. 'This summer we discovered a residential area with facilities for extraction of copper from copper ore and copper slag. We found remains of melting furnaces and about 300 kilos of ore and slag. In a room nearby, we also found evidence of production of purple textiles, which were among the most valuable commodities during the Bronze Age.'

Next to the copper extraction facility, the archaeologists exposed living quarters where they also found many interesting objects, such as locally produced ceramics of high quality and ceramics from Mycenae (in present-day Greece) and the Levant (the Eastern Mediterranean countries).

The finds also include a complete decorated bronze brooch, probably imported from northern Italy or central Europe around 1200 BC, a decorated faience bowl from Egypt, faience cylinder seals depicting warriors and hunters and figurines of people/gods and animals. All finds can be dated to the period 1400-1175 BC. 'The finds underscore the mobility of Bronze Age people far beyond their immediate surroundings. Their connections with Greece, Turkey, Egypt and the Levant may not come as a surprise, but those with Italy and central and northern Europe are very exciting. These finds lend strength to the hypothesis about major migration taking place around 1200 BC, the so-called Sea Peoples. Recent analyses of Swedish bronze objects from this period, led by Johan Ling, reader (docent) at the University of Gothenburg, suggest that bronze was imported from Cyprus,' says Fischer.

Read more at Science Daily

Paradox of Polar Ice Sheet Formation Solved

The beginning of the last glacial period was characterized in the Northern hemisphere by significant accumulation of snow at high latitudes and the formation of a huge polar ice sheet. For climatologists this was paradoxical, since snowfall is always associated with high humidity and relatively moderate temperatures. Now, a French team coordinated by María-Fernanda Sánchez-Goñi, a researcher at EPHE[1] working in the 'Oceanic and Continental Environments and Paleoenvironments' Laboratory (CNRS/Universités Bordeaux 1 & 4)[2] has solved this paradox.

By analyzing sediment cores dating back 80,000 to 70,000 years, the researchers have shown that during that period, water temperatures in the Bay of Biscay remained relatively high, whereas those in mainland Europe gradually fell. Carried northwards by wind, the humidity released by this thermal contrast appears to have caused the snowfall that formed the polar ice sheet.

This work was published on the Nature Geoscience website on 1 September 2013.

Over the past two million years, Earth has experienced long glacial periods separated by short, warmer intervals known as interglacials. This succession of glacials and interglacials is caused by changes in insolation brought about by cyclical variations in the distance between Earth and the Sun and in the tilt and direction of our planet's rotation axis relative to the Sun. The last glacial period, which ended 12,000 years ago, began between 80,000 and 70,000 years ago. This period was marked by climate variability at the millennial time scale, with short cooling periods alternating with increasingly small improvements in the climate as glaciation set in.

Sea levels dropped by 80 meters following a reduction in insolation 70,000 years ago. This shows that there was a large accumulation of snow at high latitudes, which was the cause of the ice sheet around the North Pole. However, cold temperatures are generally associated with dry weather and scarce precipitation. For snow to fall, the weather needs to be humid and the temperature only moderately low. In these conditions, how can the accumulation of snow at the pole be explained?

To answer this question, the researchers analyzed marine sediment cores collected off Galicia (Spain) and from the Bay of Biscay, containing pollen and foraminifera, microscopic marine organisms with calcareous skeletons. Pollen grains are excellent indicators of the vegetation and temperature of the continent, while foraminifera provide information about the temperature of the ocean.

Read more at Science Daily

Poop Gets Its Close-Up

Beijing may have more excrement than any city in the world, and Paris might have the most interesting sewers, but the world’s leader for breadth and depth of feces is — wait for it — Albuquerque. That’s the opinion, anyway, of New Mexico’s top poop scientist, paleontologist Adrian Hunt of the New Mexico Museum of Natural History and Science (NMMNHS).

“New Mexico is the best place in the world for fossil poop,” said Hunt at the museum’s special one day “On the Origin of Feces” event on Sunday, Sept. 1. Because of that special geological distinction the museum’s fossil feces collection is probably second only to that of the Smithsonian Institution’s, he added.

The New Mexico collection is also notable for the span of Earth’s history it covers. New Mexico’s mountains and canyons have yielded coprolites (the polite, scientific name for fossil feces) from as far back as the Permian period (250-300 million years ago) and as recent as a few thousand years ago.

The latter includes mummified dung of mammoths and ground sloths of the last ice age. Hunt has spent much of the last 22 years looking in the middle of that range, specifically at dinosaur feces.

“Nobody has looked at more fossil poop than he has,” said Spencer Lucas, curator of paleontology at the NMMNHS — fully meaning it as a compliment.

Among the many surprising discoveries made as a result of coprolites is the fact, for instance, that duck-billed dinosaurs ate conifers; as in pine trees.

“Nobody thought that duckbill dinosaurs ate conifers,” said Lucas. The lesson there, he said, is that there’s only so much you can deduce about an ancient animal’s diet from from teeth and associated fossils. “At the end of the day you have to identify the gut contents or coprolites to know what an animal ate.”.

As for how “On The Origin of Feces” went as an event, it appears to have been a hit.

“One good thing about this is that it attracts kids,” said Hunt, whose poop-laden table was near another where kids could match images of modern animal dung with various popular candies which they resemble. Kids won candy when they played the game and then impressed their parents by still finding it appetizing.

Read more at Discovery News

Sep 1, 2013

Mars Landslides Spawned By Weird Layered Craters

Scientists are a step closer to solving a 40-year-old mystery about some unusual looking craters on Mars.

These features are called double-layered ejecta (DLE) craters, and attracted research attention because their debris patterns do not match the typical understanding of how craters are formed.

Craters are pockmarks that form on the surface of a planet or moon when a high-speed rock smashes into the surface. The fast-moving collision sprays out dirt and other debris in a ring. There are more than 600 craters on Mars that have two layers of this debris, however. A new study suggests a glacial landslide would have created the second layer.

The study by Brown University geology researchers David Weiss and James Head is detailed in the Aug. 7 edition of the journal Geophysical Research Letters.

Landslides on ice

The first DLEs came into view during NASA's Viking missions to Mars in the 1970s. The twin spacecraft each carried an orbiter and a lander. While the landers made the first footfalls on Mars, the orbiters remained above for years and mapped much of the planet with their cameras.

In the decades since, scientists then uncovered extensive evidence that water and ice covered much of Mars in the distant past.

The only large deposits of ice on the Red Planet today are at the north and south poles, although icy traces linger in other areas. The DLEs, however, were formed while the Martian surface was covered by a huge sheet of glacial ice, the researchers concluded after examining past climactic studies.

At maximum, this ice sheet reached to the mid-latitudes of Mars and was about 165 feet (50 meters) thick. Ice is slippery, meaning that once the crater was formed and the debris sprayed out, the dirt slid and formed a second layer on top of the first.

Groovy observations

The theory matches up with more detailed observations of DLEs, the authors said. Many of the studied craters have radial striations, or grooves radiating from the crater's epicenter. These are common in Earth landslides, particularly those that take place on glaciers.

Steep slopes are also required to make the scenario work. The scientists calculated that the craters must be smaller than 15.5 miles (25 kilometers) in diameter to form DLEs because anything larger would have too shallow a slope. They next examined hundreds of DLEs on Mars and discovered that almost every one surveyed is that size or smaller.

Read more at Discovery News

Mosquitoes Smell You Better at Night

In work published this week in Nature: Scientific Reports, a team of researchers from the University of Notre Dame's Eck Institute for Global Health, led by Associate Professor Giles Duffield and Assistant Professor Zain Syed of the Department of Biological Sciences, revealed that the major malaria vector in Africa, the Anopheles gambiae mosquito, is able to smell major human host odorants better at night.

The study reports an integrative approach to examine the mosquito's ability to smell across the 24-hour day and involved proteomic, sensory physiological, and behavioral techniques. The researchers examined the role for a major chemosensory family of mosquito proteins, odorant-binding proteins (OBPs), in the daily regulation of olfactory sensitivities in the malarial mosquito. It is thought that OBPs in the insect antennae and mouth parts function to concentrate odorant molecules and assist in their transport to the actual olfactory receptors, thereby allowing for odorant detection. The team revealed daily rhythmic protein abundance of OBPs, having higher concentrations in the mosquito's sensory organs at night than during the day. This discovery could change the way we look at protecting ourselves from these disease-carrying pests.

The team also included Matthew M. Champion, Eck Institute for Global Health Research Assistant Professor in the Department of Chemistry and Biochemistry, who specializes in proteomics.

This study utilized mass spectrometry to quantify protein abundance in mosquito sensory organs, and electroantennograms to determine the response induced by host odorants at different times of the day. The coincident times of peak protein abundance, olfactory sensitivity and biting behavior reflect the extraordinarily fine-tuned control of mosquito physiology. Olfactory protein abundance and olfactory sensitivity are high when needed (at night) and low when not required (daytime).

Samuel Rund, a doctoral candidate in the laboratory of Duffield and a former Eck Institute for Global Health Fellow, and Nicolle Bonar, a visiting undergraduate student from Queens University of Ontario, Canada, were the lead authors on this research. The Notre Dame team also included then-undergraduate student John Ghazi, Class of 2012; undergraduate Cameron Houk, Class of '14; and graduate student Matthew Leming.

Rund noted, "This was an exciting opportunity to bring many people and techniques together to make some really fascinating findings on the mosquito's ability to smell humans, its host. Just think, during the day the mosquito is sleeping and doesn't need to smell you. But when the sun goes down, the mosquito's olfactory system becomes extra-sensitive, and she is ready to smell and then bite you."

The project was a follow-up to their earlier work that utilized genomic tools to reveal 24-hour rhythmic patterns of gene expression, including many genes involved in olfaction.

Rund and Duffield's earlier work with collaborator James Gentile from Notre Dame's Department of Computer Science and Engineering, "Extensive circadian and light regulation of the transcriptome in the malaria mosquito Anopheles gambiae," helped lay some of the foundation to their findings. The paper, published in BMC Genomics in April, further examined the regulation of rhythms in gene expression at the molecular level, highlighted important differences in biological timing between Anopheles gambiae and the important dengue vector, Aedes aegypti, and highlighted the important role of light in organizing and modifying gene expression.

Read more at Science Daily