Monday, February 28, 2011


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Great works and praiseworthy behavior may bring respect and admiration, but these won't help us to escape blame when we do something wrong, says a new study by researchers at the University of Maryland and Harvard University. To do that, the researchers say, one needs to be a victim not a hero!

In the study, participants responded to a number of scenarios that mirrored real-life moral transgressions, from stealing money to harming someone. Results revealed that, no matter how many previous good deeds someone had done, they received just as much blame - if not more - than someone with a less heroic background.

"People may come down even harder on someone like the Dalai Lama, than they do on 'Joe Blow,' said author Kurt Gray, assistant professor of psychology at the University of Maryland." However, in our research those who have suffered in the past received significantly less blame - even if such suffering was both totally unrelated to the misdeed and long since past."

The article, titled "To Escape Blame, Don't be a Hero - be a Victim" is published in the March issue of the Journal of Experimental Social Psychology. The findings are based on three experiments conducted by Gray and Daniel Wegner, professor of psychology at Harvard University.

"Our research suggests that morality is not like some kind of cosmic bank, where you can deposit good deeds and use them to offset future misdeeds," said Gray, who directs the Mind Perception and Morality Lab at the University of Maryland. "Instead, people ignore heroic pasts - or even count them against you - when assigning blame."

Gray suggests that the explanation for these findings is our tendency to divide the world up into moral agents - those who do good and evil - and moral patients - those who receive good or evil. "Psychologically, the perceived distance between a hero and a villain is quite small, whereas there's a wide gap between a villain and a victim. This means that heroes are easily recast as evil doers, whereas it's very hard to turn a victim into a villain."

In the experiments involved in this study, those who highlighted past suffering were held less responsible for transgressions and given less punishment. According to the authors, this fact suggests an explanation for why many celebrities immediately go into rehab or claim victimhood after being caught doing something wrong. Of course, this research doesn't address whether someone is actually blameworthy, but it does indicate a clear strategy for escaping blame.

In fact their research finds that people had trouble even remembering the misdeeds of victims. In one experiment, people read about either a hero, normal person, or a victim stealing some money, and then were given a surprise memory test after. Far fewer people remembered the victim stealing money.

The authors note that there certainly are benefits from good deeds for both individuals and society. For example they say, "not only do virtuous deeds help the recipient of the deed, but research suggests that even small acts of good can serve to significantly improve the doers mood."

But "whether you are trying to defend yourself against a spouse's wrath for a missed birthday or save yourself from execution for a grisly murder, your task is to become the ultimate victim . . . with stories of childhood abuse, of broken hearts and broken arms," Gray and Wegner write.

(Photo: Butch Kriege)

University of Maryland


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Geologists drilling an exploratory geothermal well in 2009 in the Krafla volcano in Iceland encountered a problem they were simply unprepared for: magma (molten rock or lava underground) which flowed unexpectedly into the well at 2.1 kilometers (6,900 ft) depth, forcing the researchers to terminate the drilling.

"To the best of our knowledge, only one previous instance of magma flowing into a geothermal well while drilling has been documented," said Wilfred Elders, a professor emeritus of geology in the Department of Earth Sciences at the University of California, Riverside, who led the research team. "We were drilling a well that was designed to search for very deep – 4.5 kilometers (15,000 feet) – geothermal resources in the volcano. While the magma flow interrupted our project, it gave us a unique opportunity to study the magma and test a very hot geothermal system as an energy source."

Currently, a third of the electric power and 95 percent of home heating in Iceland is produced from steam and hot water that occurs naturally in volcanic rocks.

"The economics of generating electric power from such geothermal steam improves the higher its temperature and pressure," Elders explained. "As you drill deeper into a hot zone the temperature and pressure rise, so it should be possible to reach an environment where a denser fluid with very high heat content, but also with unusually low viscosity occurs, so-called 'supercritical water.' Although such supercritical water is used in large coal-fired electric power plants, no one had tried to use supercritical water that should occur naturally in the deeper zones of geothermal areas."

Elders and colleagues report in the March issue of Geology (the research paper was published online on Feb. 3) that although the Krafla volcano, like all other volcanoes in Iceland, is basaltic (a volcanic rock containing 45-50 percent silica), the magma they encountered is a rhyolite (a volcanic rock containing 65-70 percent silica).

"Our analyses show that this magma formed by partial melting of certain basalts within the Krafla volcano," Elders said. "The occurrence of minor amounts of rhyolite in some basalt volcanoes has always been something of a puzzle. It had been inferred that some unknown process in the source area of magmas, in the mantle deep below the crust of the Earth, allows some silica-rich rhyolite melt to form in addition to the dominant silica-poor basalt magma."

Elders explained that in geothermal systems water reacts with and alters the composition of the rocks, a process termed "hydrothermal alteration." "Our research shows that the rhyolite formed when a mantle-derived basaltic magma encountered hydrothermally altered basalt, and partially melted and assimilated that rock," he said.

Elders and his team studied the well within the Krafla caldera as part of the Iceland Deep Drilling Project, an industry-government consortium, to test whether geothermal fluids at supercritical pressures and temperatures could be exploited as sources of power. Elders's research team received support of $3.5 million from the National Science Foundation and $1.5 million from the International Continental Scientific Drilling Program.

In the spring of 2009 Elders and his colleagues progressed normally with drilling the well to 2 kilometers (6,600 feet) depth. In the next 100 meters (330 feet), however, multiple acute drilling problems occurred. In June 2009, the drillers determined that at 2104 meters (6,900 feet) depth, the rate of penetration suddenly increased and the torque on the drilling assembly increased, halting its rotation. When the drill string was pulled up more than 10 meters (33 feet) and lowered again, the drill bit became stuck at 2095 meters (6,875 feet). An intrusion of magma had filled the lowest 9 meters (30 feet) of the open borehole. The team terminated the drilling and completed the hole as a production well.

"When the well was tested, high pressure dry steam flowed to the surface with a temperature of 400 Celsius or 750 Fahrenheit, coming from a depth shallower than the magma," Elders said. "We estimated that this steam could generate 25 megawatts of electricity if passed through a suitable turbine, which is enough electricity to power 25,000 to 30,000 homes. What makes this well an attractive source of energy is that typical high-temperature geothermal wells produce only 5 to 8 megawatts of electricity from 300 Celsius or 570 Fahrenheit wet steam."

Elders believes it should be possible to find reasonably shallow bodies of magma, elsewhere in Iceland and the world, wherever young volcanic rocks occur.

"In the future these could become attractive sources of high-grade energy," said Elders, who got involved in the project in 2000 when a group of Icelandic engineers and scientists invited him to join them to explore concepts of developing geothermal energy.

The Iceland Deep Drilling Project has not abandoned the search for supercritical geothermal resources. The project plans to drill a second deep hole in southwest Iceland in 2013.

(Photo: Bjarni Palssen)

University of California, Riverside


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It has been long known that stress plays a part not just in the graying of hair but in hair loss as well. Over the years, numerous hair-restoration remedies have emerged, ranging from hucksters' "miracle solvents" to legitimate medications such as minoxidil. But even the best of these have shown limited effectiveness.

Now, a team led by researchers from UCLA and the Veterans Administration that was investigating how stress affects gastrointestinal function may have found a chemical compound that induces hair growth by blocking a stress-related hormone associated with hair loss — entirely by accident.

The serendipitous discovery is described in an article published in the online journal PLoS One.

"Our findings show that a short-duration treatment with this compound causes an astounding long-term hair regrowth in chronically stressed mutant mice," said Million Mulugeta, an adjunct professor of medicine in the division of digestive diseases at the David Geffen School of Medicine at UCLA and a corresponding author of the research. "This could open new venues to treat hair loss in humans through the modulation of the stress hormone receptors, particularly hair loss related to chronic stress and aging."

The research team, which was originally studying brain–gut interactions, included Mulugeta, Lixin Wang, Noah Craft and Yvette Taché from UCLA; Jean Rivier and Catherine Rivier from the Salk Institute for Biological Studies in La Jolla, Calif.; and Mary Stenzel-Poore from the Oregon Health and Sciences University.

For their experiments, the researchers had been using mice that were genetically altered to overproduce a stress hormone called corticotrophin-releasing factor, or CRF. As these mice age, they lose hair and eventually become bald on their backs, making them visually distinct from their unaltered counterparts. The Salk Institute researchers had developed the chemical compound, a peptide called astressin-B, and described its ability to block the action of CRF. Stenzel-Poore had created an animal model of chronic stress by altering the mice to overproduce CRF.

UCLA and VA researchers injected the astressin-B into the bald mice to observe how its CRF-blocking ability affected gastrointestinal tract function. The initial single injection had no effect, so the investigators continued the injections over five days to give the peptide a better chance of blocking the CRF receptors. They measured the inhibitory effects of this regimen on the stress-induced response in the colons of the mice and placed the animals back in their cages with their hairy counterparts.

About three months later, the investigators returned to these mice to conduct further gastrointestinal studies and found they couldn't distinguish them from their unaltered brethren. They had regrown hair on their previously bald backs.

"When we analyzed the identification number of the mice that had grown hair we found that, indeed, the astressin-B peptide was responsible for the remarkable hair growth in the bald mice," Mulugeta said. "Subsequent studies confirmed this unequivocally."

Of particular interest was the short duration of the treatments: Just one shot per day for five consecutive days maintained the effects for up to four months.

"This is a comparatively long time, considering that mice's life span is less than two years," Mulugeta said.

So far, this effect has been seen only in mice. Whether it also happens in humans remains to be seen, said the researchers, who also treated the bald mice with minoxidil alone, which resulted in mild hair growth, as it does in humans. This suggests that astressin-B could also translate for use in human hair growth. In fact, it is known that the stress-hormone CRF, its receptors and other peptides that modulate these receptors are found in human skin.


Saturday, February 26, 2011

Oldest fossils of large seaweeds, possible animals tell story about oxygen in an ancient ocean

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Almost 600 million years ago, before the rampant evolution of diverse life forms known as the Cambrian explosion, a community of seaweeds and worm-like animals lived in a quiet deep-water niche under the sea near what is now Lantian, a small village in Anhui Province of South China. Then they simply died, leaving some 3,000 nearly pristine fossils preserved between beds of black shale deposited in oxygen-free waters.

Scientists from the Chinese Academy of Sciences, Virginia Tech in the U.S., and Northwest University in Xi'an, China report the discovery of the fossils and the mystery in the Feb. 17 issue of Nature.

In addition to perhaps ancient versions of algae and worms, the Lantian biota – named for its location – included macrofossils with complex and puzzling structures. In all, scientists identified about 15 different species at the site.

The fossils suggest that morphological diversification of macroscopic eukaryotes – the earliest versions of organisms with complex cell structures -- may have occurred only tens of millions of years after the snowball earth event that ended 635 million years ago, just before the Ediacaran Period. And their presence in the highly organic-rich black shale suggests that, despite the overall oxygen-free conditions, brief oxygenation of the oceans did come and go.

"So there are two questions," said Shuhai Xiao, professor of geobiology in the College of Science at Virginia Tech. "Why did this community evolve when and where it did? It is clearly different in terms of the number of species compared to biotas preserved in older rocks. There are more species here and they are more complex and larger than what evolved before. These rocks were formed shortly after the largest ice age ever, when much of the global ocean was frozen. By 635 million years ago, the snowball earth event ended and oceans were clear of ice. Perhaps that prepared the ground for the evolution of complex eukaryotes."

The team was examining the black shale rocks because, although they were laid down in waters that were not good for oxygen-dependent organisms, "they are known to be able to preserve fossils very well," said Shuhai. "In most cases, dead organisms were washed in and preserved in black shales. In this case, we discovered fossils that were preserved in pristine condition where they had lived – some seaweeds still rooted."

The conclusion that the environment would have been poisonous is derived from geochemical data, "but the bedding surfaces where these fossils were found represent moments of geological time during which free oxygen was available and conditions were favorable. They are very brief moments to a geologist," said Xiao. "but long enough for the oxygen-demanding organisms to colonize the Lantian basin and capture the rare opportunities."

The research team suggests in the article in Nature that the Lantian basin was largely without oxygen but was punctuated by brief oxic episodes that were opportunistically populated by complex new life forms, which were subsequently killed and preserved when the oxygen disappeared. "Such brief oxic intervals demand high-resolution sampling for geochemical analysis to capture the dynamic and complex nature of oxygen history in the Ediacaran Period," said lead author Xunlai Yuan, professor of palaeontology with the Chinese Academy of Sciences.

Proving that hypothesis awaits further study. The rocks in the study region are deposited in layered beds. The nature of the rock changes subtly and there are finer and finer layers that can be recognized within each bed. "We will need to sample each layer to see whether there is any difference in oxygen contents between layers with fossils and those without" said co-author Chuanming Zhou, professor of palaeontology with the Chinese Academy of Sciences.

(Photo: Zhe Chen)

Zinc reduces the burden of the common cold

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Zinc supplements reduce the severity and duration of illness caused by the common cold, according to a systematic review published in The Cochrane Library. The findings could help reduce the amount of time lost from work and school due to colds.

The common cold places a heavy burden on society, accounting for approximately 40% of time taken off work and millions of days of school missed by children each year. The idea that zinc might be effective against the common cold came from a study carried out in 1984, which showed that zinc lozenges could reduce how long symptoms lasted. Since then, trials have produced conflicting results and although several biological explanations for the effect have been proposed, none have been confirmed.

The review updates a previous Cochrane Systematic Review, carried out in 1999, with data from several new trials. In total, data from 15 trials, involving 1,360 people, were included. According to the results, zinc syrup, lozenges or tablets taken within a day of the onset of cold symptoms reduce the severity and length of illness. At seven days, more of the patients who took zinc had cleared their symptoms compared to those who took placebos. Children who took zinc syrup or lozenges for five months or longer caught fewer colds and took less time off school. Zinc also reduced antibiotic use in children, which is important because overuse has implications for antibiotic resistance.

"This review strengthens the evidence for zinc as a treatment for the common cold," said lead researcher Meenu Singh of the Post Graduate Institute of Medical Education and Research in Chandigarh, India. "However, at the moment, it is still difficult to make a general recommendation, because we do not know very much about the optimum dose, formulation or length of treatment."

Further research should focus on the benefits of zinc in defined populations, the review suggests. "Our review only looked at zinc supplementation in healthy people," said Singh. "But it would be interesting to find out whether zinc supplementation could help asthmatics, whose asthma symptoms tend to get worse when they catch a cold." The researchers also say that more work needs to be carried out in low-income countries, where zinc deficiency may be prevalent.


Earliest humans not so different from us, research suggests

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That human evolution follows a progressive trajectory is one of the most deeply-entrenched assumptions about our species. This assumption is often expressed in popular media by showing cavemen speaking in grunts and monosyllables (the GEICO Cavemen being a notable exception). But is this assumption correct? Were the earliest humans significantly different from us?

In a paper published in the latest issue of Current Anthropology, archaeologist John Shea (Stony Brook University) shows they were not.

The problem, Shea argues, is that archaeologists have been focusing on the wrong measurement of early human behavior. Archaeologists have been searching for evidence of "behavioral modernity", a quality supposedly unique to Homo sapiens, when they ought to have been investigating "behavioral variability," a quantitative dimension to the behavior of all living things.

Human origins research began in Europe, and the European Upper Paleolithic archaeological record has long been the standard against which the behavior of earlier and non-European humans is compared. During the Upper Paleolithic (45,000-12,000 years ago), Homo sapiens fossils first appear in Europe together with complex stone tool technology, carved bone tools, complex projectile weapons, advanced techniques for using fire, cave art, beads and other personal adornments. Similar behaviors are either universal or very nearly so among recent humans, and thus, archaeologists cite evidence for these behaviors as proof of human behavioral modernity.

Yet, the oldest Homo sapiens fossils occur between 100,000-200,000 years ago in Africa and southern Asia and in contexts lacking clear and consistent evidence for such behavioral modernity. For decades anthropologists contrasted these earlier "archaic" African and Asian humans with their "behaviorally-modern" Upper Paleolithic counterparts, explaining the differences between them in terms of a single "Human Revolution" that fundamentally changed human biology and behavior. Archaeologists disagree about the causes, timing, pace, and characteristics of this revolution, but there is a consensus that the behavior of the earliest Homo sapiens was significantly that that of more-recent "modern" humans.

Shea tested the hypothesis that there were differences in behavioral variability between earlier and later Homo sapiens using stone tool evidence dating to between 250,000- 6000 years ago in eastern Africa. This region features the longest continuous archaeological record of Homo sapiens behavior. A systematic comparison of variability in stone tool making strategies over the last quarter-million years shows no single behavioral revolution in our species' evolutionary history. Instead, the evidence shows wide variability in Homo sapiens toolmaking strategies from the earliest times onwards. Particular changes in stone tool technology can be explained in terms of the varying costs and benefits of different toolmaking strategies, such as greater needs for cutting edge or more efficiently-transportable and functionally-versatile tools. One does not need to invoke a "human revolution" to account for these changes, they are explicable in terms of well-understood principles of behavioral ecology.

This study has important implications for archaeological research on human origins. Shea argues that comparing the behavior of our most ancient ancestors to Upper Paleolithic Europeans holistically and ranking them in terms of their "behavioral modernity" is a waste of time. There are no such things as modern humans, Shea argues, just Homo sapiens populations with a wide range of behavioral variability. Whether this range is significantly different from that of earlier and other hominin species remains to be discovered. However, the best way to advance our understanding of human behavior is by researching the sources of behavioral variability in particular adaptive strategies.

The University of Chicago Press

Friday, February 25, 2011


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With one arm raised and a determined scowl, the figure looks ready to march right off his carved tablet and into the history books. If only we knew who he was - corn god? Tribal chief? Sacred priest?

"It's beautiful and was obviously very important," says University of Wisconsin-Madison archaeologist John Hodgson of the newly discovered stone monument. "But we will probably never know who he was or what the sculpture means in its entirety."

The man is the central figure on a stone monument discovered in 2009 at a site called Ojo de Agua in far southern Mexico in the state of Chiapas along the Pacific coast. Hodgson, a doctoral candidate in anthropology at UW-Madison, describes the new monument in the cover article of the current issue (December 2010) of Mexicon, a leading peer-reviewed journal of Mesoamerican studies. The article, titled "Ojo de Agua Monument 3: A New Olmec-Style Sculpture from Ojo de Agua, Chiapas, Mexico," is co-authored with John E. Clark, of Brigham Young University, and Emiliano Gallaga Murrieta, director of the National Institute of Anthropology and History in Chiapas.

Monument 3 is just the second carved monument found in Ojo de Agua. Monument 1 was discovered accidently when a local farmer hit it with a plow in the 1960s. Monument 3 was a similarly fortuitous finding, uncovered in the process of digging an irrigation ditch. (Monument 2 is a large boulder with a flat surface and no visible carving, which Hodgson found in 2005 and reported in the January/February 2006 issue of Archaeology magazine in an article on Ojo de Agua.)

Hodgson was working in the area and received word of the finding within just a few days of its discovery. He was able to see the monument's impression in the trench wall and study the soil layers where it had been buried, gaining a wealth of information that is usually lost long before any archaeologist lays eyes on a piece.

"Usually sculptures are first seen by archaeologists in private art collections and we normally have no good idea where they came from. The depictions of figures and the motifs change in form through time so you can get an approximate date by comparing styles," he says. "But we were able to date the new monument by where it was found to a narrow 100-year window, which is very rare."

The archaeological context and radiocarbon dating of ceramic sherds associated with the stone monument show that it dates to 1100 to 1000 B.C., making it approximately 3,000 years old. Its age and style correspond to the Early Formative period, when an early culture known as the Olmec dominated the area.

Its purpose and meaning, however, will be harder to ascertain.

"Everything means something in this kind of culture," says pre-eminent archaeologist Michael D. Coe, a professor emeritus of anthropology at Yale University and expert on Mesoamerican civilizations. "It obviously was a public monument — an important one, probably in connection with some really big cheese who lorded it over the area." Coe was not directly involved in the work but is familiar with the newly discovered monument.

"It appears to me to be a depiction of an event or a way to convey other types of information," Hodgson adds. "This dates to a time prior to a developed written language, but like the modern symbol used internationally for the Red Cross, symbols are very efficient at communicating complicated ideas."

The main figure on the tablet is depicted wearing an elaborate headdress, loincloth and ornate accessories, including a pair of large, comb-like ear ornaments, a rope-like necklace and a thick belt with a jaguar-head buckle. A face on the headdress includes features such as sprouting plants that identify it as a corn god. The tablet also includes a smaller secondary figure and a series of asymmetric zigzag designs that the authors suggest could represent lightning, local mountain ranges, or other features of the natural world.

"This is closely connected with agriculture and the cult of the corn god," Coe says, pointing out the zigzags. "Thunderstorms bring the rain."

The monument is a carved flat slab of a relatively soft, local volcanic stone that weighs about 130 pounds. It stands nearly three feet tall, about 14 inches wide, and ranges from four to seven inches thick. The use of local materials shows it was made in or near Ojo de Agua, Hodgson says, but style similarities to pieces found in larger Olmec centers near the Gulf of Mexico and the Valley of Mexico indicate pan-regional influences as well.

"It's cruder in execution than most Olmec monuments from the other side of the isthmus — 'provincial' Olmec," Coe says. But despite lacking some of the intricate artistry, it is still relatively sophisticated, he says. "This adds to our knowledge of the Olmec on the south side of the isthmus."

The depiction of corn is particularly notable. Corn cultivation is generally associated with a settled lifestyle rather than a nomadic existence, indicating that Ojo de Agua was almost certainly a farming community. The grain's storability and nutritional content also would have allowed the population to expand drastically and the civilization to become more complex, Hodgson says, adding that "the early date of the monument supports the idea that there was an early association between corn and religion."

Ojo de Agua lies in the heart of the ancient Aztec province Soconusco, nestled in a bend of the Coatán River. It is the earliest known site in Mesoamerica with formal pyramids built around plazas.

Though it has not been worked very extensively as an archeological site, Ojo de Agua appears to cover about 200 hectares and is the largest site in the area from the time period 1200-1000 B.C. The limited work to date describes civic architecture consistent with a decent-sized planned settlement. The identified platform mounds are laid out in a deliberate alignment that may be relative to magnetic north.

"That's something we see later but to see it this early is pretty surprising," says Hodgson, who has been working at Ojo de Agua since 2003.

The site appears to have been occupied for 150 to 200 years before being abandoned for unknown reasons.

Hodgson expects there are many more clues at Ojo de Agua and hopes to have the opportunity to continue working at the site and perhaps another look at Monument 3.

"We've just scratched the surface there. The things we've found are fantastic," Hodgson says. "These early societies were a lot more complicated than we thought they were."

(Photo: John Hodgson; Drawing: Kisslan Chan and John Clark, New World Archaeological Foundation)

University of Wisconsin-Madison


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Think you're overloaded with information? Not even close. A study appearing on Feb. 10 in Science Express, an electronic journal that provides select Science articles ahead of print, calculates the world's total technological capacity — how much information humankind is able to store, communicate and compute.

"We live in a world where economies, political freedom and cultural growth increasingly depend on our technological capabilities," said lead author Martin Hilbert of the USC Annenberg School for Communication & Journalism. "This is the first time-series study to quantify humankind's ability to handle information."

So how much information is there in the world? How much has it grown?

Prepare for some big numbers:

* Looking at both digital memory and analog devices, the researchers calculate that humankind is able to store at least 295 exabytes of information. (Yes, that's a number with 20 zeroes in it.)

Put another way, if a single star is a bit of information, that's a galaxy of information for every person in the world. That's 315 times the number of grains of sand in the world. But it's still less than one percent of the information that is stored in all the DNA molecules of a human being.

* 2002 could be considered the beginning of the digital age, the first year worldwide digital storage capacity overtook total analog capacity. As of 2007, almost 94 percent of our memory is in digital form.

* In 2007, humankind successfully sent 1.9 zettabytes of information through broadcast technology such as televisions and GPS. That's equivalent to every person in the world reading 174 newspapers every day.

* On two-way communications technology, such as cell phones, humankind shared 65 exabytes of information through telecommunications in 2007, the equivalent of every person in the world communicating the contents of six newspapers every day.

* In 2007, all the general-purpose computers in the world computed 6.4 x 10^18 instructions per second, in the same general order of magnitude as the number of nerve impulses executed by a single human brain. Doing these instructions by hand would take 2,200 times the period since the Big Bang.

* From 1986 to 2007, the period of time examined in the study, worldwide computing capacity grew 58 percent a year, ten times faster than the United States' GDP.

Telecommunications grew 28 percent annually, and storage capacity grew 23 percent a year.

"These numbers are impressive, but still miniscule compared to the order of magnitude at which nature handles information" Hilbert said. "Compared to nature, we are but humble apprentices. However, while the natural world is mind-boggling in its size, it remains fairly constant. In contrast, the world's technological information processing capacities are growing at exponential rates."

(Photo: USC)



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According to Dr Annette Baudisch of the Max Planck Institute for Demographic Research in Rostock, Germany, current methods of comparing patterns of ageing are limited because they confound two different elements of ageing – pace and shape.

"Some organisms live a short time, others live a long time. This is the pace of ageing. Short-lived species have a fast pace of ageing, and long-lived species have a slow pace of ageing. Pace describes how quickly the clock of life ticks away. For humans it ticks slowly, for small songbirds like the robin it ticks very fast," explains Dr Baudisch.

By contrast the shape of ageing describes how much mortality – the risk of dying – changes with age. One way of measuring the shape of ageing is the 'ageing factor'. For example, the common swift has an ageing factor of 2, meaning mortality doubles during its adult life, compared with modern humans, who have an ageing factor that exceeds 2000.

"At the age of 15, only 2 out of 100,000 girls in Sweden die, but one out of every two women aged 110 will die. This large difference in mortality at the beginning and end of adult life means that for humans the shape of ageing is steep, whereas in other species like the common swift it is shallow. And in some species the risk of death can even fall with age, with older individuals having the least risk of dying. This seems to be the case for the desert tortoise, and for alligators or crocodiles."

Using data for 10 different groups of animals from herring gull, European robin, common swift and lake sturgeon to Dall mountain sheep, African buffalo, wild and captive chimpanzees, hunter-gatherers and modern humans (Swedish women), Dr Baudisch classified how each species aged in terms of pace and shape of ageing.

Of the species she analysed, Dr Baudisch found that although modern humans are the longest-lived, they also age most strongly.

Adult life expectancy for Swedish women (that is the remaining life expectancy after reaching maturity) is about 70 years, whereas a robin's adult life lasts just 1.7 years. But over that adult lifespan, ageing is so strong in the human that the ageing factor is 2132, but for the robin only about 2.

"Comparing robins with Swedish women, humans have a slow pace of ageing whereas the robin's is fast, so in terms of length of life the humans are doing best. But if we look at the impact ageing has on death rate the robin wins. Its shape of ageing is fairly flat whereas the humans' is steep, indicating that death rates increase markedly with age," she says.

Dr Baudisch's results have important implications for evolutionary biology and the study of ageing: "We need to compare species to understand how evolution has shaped the biology of ageing in different species, but current methods of comparing patterns of ageing across species are limited because they confound the pace and shape of ageing. Not accounting for this difference can lead to incorrect conclusions about which species age more than others."

"Separating pace from shape of ageing gives a clearer picture of the characteristics of ageing. It could reveal that certain species are very similar to each other in terms of their shape of ageing, species that we would maybe never have grouped together. Ultimately, this should help us identify the determinants of ageing – the characteristics that determine whether death rates goes up or down with age and reveal species that can successfully avoid ageing," she says.

In more everyday terms, her results might make us re-think common expressions, such as "live fast, die young". As dying young in Dr Baudisch's terms corresponds to a small ageing factor and dying old to a large one, "live fast, die young" only applies to some short-lived species.

Robins live fast and die young, but even though Dall mountain sheep only live for around 4.2 years, their ageing factor is 7.

"Not all species with short lives live fast and die young. Robins do, but mountain sheep do things differently. They also live pretty fast but die older. From the data I have, it seems that live fast die young is only one option; you can also live fast and die older, or live slower and die young, or live slow and die old. There might be every combination in nature. That's something we need to find out in the future with better data."


Thursday, February 24, 2011

Centuries of Sailors Weren’t Wrong: Looking at the Horizon Stabilizes Posture

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Everybody who has been aboard a ship has heard the advice: if you feel unsteady, look at the horizon. For a study published in Psychological Science, a journal of the Association for Psychological Science, researchers measured how much people sway on land and at sea and found there’s truth in that advice; people aboard a ship are steadier if they fix their eyes on the horizon.

Thomas A. Stoffregen of the University of Minnesota has been studying “body sway” for decades—how much people rock back and forth in different situations, and what this has to do with motion sickness. In just a normal situation, standing still, people move back and forth by about four centimeters every 12 to 15 seconds. Stoffregen and his coauthors, Anthony M. Mayo and Michael G. Wade, wanted to know how this changes when you’re standing on a ship.

To study posture at sea, Stoffregen made contact with the U.S. consortium that runs scientific research ships. “I’m really an oddball for these folks, because they’re studying oceanography, like hydrothermal vents. Here’s this behavioral scientist, calling them up,” he says. He boards a ship when it is travelling between different projects—for example, in this study, he rode on the research vessel Atlantis as it went between two points in the Gulf of California. “It had nothing to do with the fact that I like cruising near the tropics,” he jokes. Since the ships are between scientific expeditions, he can sleep in one of the empty bunks normally reserved for ocean scientists, and crew members volunteer to take part in his study.

The study compared the same people standing on dry land—a dock in Guaymas, Mexico—and aboard the ship. In each experiment, the crew member stood comfortably on a force plate and focused on a target—either something about 16 inches in front of them, or a far-off point; a distant mountain when standing on land or the horizon when standing on the ship. On land, people were steadier when they looked at the close-up target and swayed more when they looked far away. On the ship, however, they were steadier when they looked at the horizon.

This is actually counterintuitive, Stoffregen says. When you’re standing on a ship, you need to adjust to the ship’s movement, or you’ll fall over. So why would it help to look at the horizon and orient yourself to the Earth? He thinks it may help stabilize your body by helping you differentiate between sources of movement—the natural movement coming from your body and the movement caused by the ship.

Stoffregen thinks this motion of bodies may predict motion sickness. “It’s the people who become wobbly who subsequently become motion sick,” he says. He had originally hoped to study seasickness directly, but so far his subjects have all been seasoned crew members who are used to the ship’s movement and don’t get sick; his dream is to do his experiments aboard a ship full of undergraduate oceanography majors going to sea for the first time. “I’d give my right arm to get on one of those.”

Association for Psychological Science

Scientists Determine What Makes an Orangutan an Orangutan

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For the first time, scientists have mapped the genome--the genetic code--of orangutans. This new tool may be used to support efforts to maintain the genetic diversity of captive and wild orangutans. The new map of the orangutan genome may also be used to help improve our understanding of the evolution of primates, including humans.

Partially funded by the National Science Foundation, the orangutan study appeared in the Jan. 27 issue of Nature. It was conducted by an international team of scientists led by Devin P. Locke of the Genome Center at Washington University.

The name "orangutan" is derived from the Malay term, "man of the forest," a fitting moniker for one of our closest relatives.

There are two species of orangutans, defined primarily by their island of origin--either Sumatra or Borneo. The outlook for orangutan survival is currently dire because there are estimated to be only about 7,500 orangutans in Sumatra, where they are considered critically endangered, and only about 50,000 orangutans in Borneo, where they are considered endangered.

The endangerment status of orangutans is determined by the International Union for Conservation of Nature.

There are no other wild populations of orangutans other than those in Sumatra and Borneo. The decline of the Sumatran and Borneo populations of orangutans is caused by varied threats, such as illegal logging, the conversion of rain forests to farmland and palm oil plantations, hunting and diseases.

Using a mix of legacy and novel technologies, the research team mapped the genomes of a total of 11 orangutans, including representatives of both the Sumatran and Bornean species.

The map of the orangutan genome may support conservation efforts by helping zoos create breeding programs designed to maintain the genetic diversity of captive populations. (The greater the genetic diversity of a species, the more resilient it is against threats to its survival.) The genome map may also help conservationists sample the genetic diversity of wild populations so they can prioritize populations of wild orangutans for conservation efforts.

After scientists map a species' genome, they compare it to the genetic maps of other species. As they do so, they search for key differences that involve duplications, deletions and inversions of genetic material. These differences may contribute to the unique features of particular species. They may also provide information about general evolutionary trends, such as the overall rate at which genomic evolution has occurred.

Before the orangutan's genome was mapped, the genetic codes of three other great primates--humans, chimpanzees and rhesus macaques--were mapped.

The genomes of the gorilla and bonobo will soon be mapped, as well.

Analyses of the orangutan genome reveal that this primate has many unique features. For example, comparisons of the structural variation of the genomes of orangutans, humans, chimpanzees and rhesus macaques indicate that during the last 15 million years or so of primate evolution, the orangutan genome has generally been more stable than those of the other primates, with fewer large-scale structural changes.

The orangutan genome also allowed for an analysis of fast-evolving genes, which are likely to have responded to evolutionary pressure for adaptation. Genes related to visual perception and metabolic processes were found to evolve unusually rapidly in orangutans and other primates. The orangutan's metabolism-related genes were also found to have evolved rapidly--a phenomenon that may be related to the orangutan's slow growth rate, slow reproduction rate, and long inter-birth interval, the period between successive births. Orangutans give birth not more than once every six to eight years, an inter-birth interval rated as the longest among mammals, including humans.

Comparisons of the population genetics of the Sumatran and Bornean species indicate that these species split approximately 400,000 years ago, which is more recent than previously believed. In addition, Sumatran orangutans have greater genetic diversity than their Bornean counterparts, despite their smaller population size and higher endangered status.

Adam Siepel, a research team member from Cornell University described the new map of the genetic code of orangutans as an important step in genome sequencing of primates. "The orangutan genome gives us a much more complete picture of genome evolution in the great apes," he said.

"This is a terrific example of the application of genome sequencing beyond model organisms--well-studied organism like the mouse and fruit fly," said Reed Beaman, an NSF program director. "Research like this has only recently become possible through a dramatic decrease in the cost of sequencing. These results demonstrate broad significance to biogeography, genetics, as well as to conservation and human evolution, and they are only starting to scratch the surface."

(Photo: © 2011 Jupiter Images Corporation)

National Science Foundation (NSF)

The Most Genes in an Animal? Tiny Crustacean Holds the Record

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Scientists have discovered that the animal with the most genes--about 31,000--is the near-microscopic freshwater crustacean Daphnia pulex, or water flea.

By comparison, humans have about 23,000 genes. Daphnia is the first crustacean to have its genome sequenced.

The water flea's genome is described in a Science paper published by members of the Daphnia Genomics Consortium, an international network of scientists led by the Center for Genomics and Bioinformatics (CGB) at Indiana University (IU) Bloomington and the U.S. Department of Energy's Joint Genome Institute.

"Daphnia's high gene number is largely because its genes are multiplying, creating copies at a higher rate than other species," said project leader and CGB genomics director John Colbourne.

"We estimate a rate that is three times greater than those of other invertebrates and 30 percent greater than that of humans."

"This analysis of the Daphnia genome significantly advances our understanding of how an organism's genome interacts with its environment both to influence genome structure and to confer ecological and evolutionary success," says Saran Twombly, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research.

"This gene-environment interplay has, to date, been studied in model organisms under artificial, laboratory conditions," says Twombly.

"Because the ecology of Daphnia pulex is well-known, and the organism occurs abundantly in the wild, this analysis provides unprecedented insights into the feedback between genes and environment in a real and ever-changing environment."

Daphnia's genome is no ordinary genome.

What reasons might Daphnia have so many genes compared to other animals?

A possibility, Colbourne said, is that "since the majority of duplicated and unknown genes are sensitive to environmental conditions, their accumulation in the genome could account for Daphnia's flexible responses to environmental change."

Scientists have studied Daphnia for centuries because of its importance in aquatic food webs and for its transformational responses to environmental stress.

Like the virgin nymph of Greek mythology that shares its name, Daphnia thrives in the absence of males--by clonal reproduction, until harsh environmental conditions favor the benefits of sex.

"More than one-third of Daphnia's genes are undocumented in any other organism--in other words, they are completely new to science," says Don Gilbert, paper co-author and scientist at IU Bloomington.

Sequenced genomes often contain some fraction of genes with unknown functions, even among the most well-studied genetic model species for biomedical research, such as the fruit fly Drosophila.

By using microarrays (containing millions of DNA strands affixed to microscope slides), experiments that subjected Daphnia to environmental stressors point to these unknown genes having ecologically significant functions.

"If such large fractions of genomes evolved to cope with environmental challenges, information from traditional model species used only in laboratory studies may be insufficient to discover the roles for a considerable number of animal genes," Colbourne said.

Daphnia is emerging as a model organism for a new field of science--environmental genomics--that aims to better understand how the environment and genes interact.

This includes a practical need to apply scientific developments from this field to managing our water resources and protecting human health from chemical pollutants in the environment.

James Klaunig, a scientist at IU Bloomington, predicts that the work will yield a more realistic and scientifically-based risk evaluation.

"Genome research on the responses of animals to stress has important implications for assessing environmental risks to humans," Klaunig said. "Daphnia is an exquisite aquatic sensor, a potential high-tech and modern version of the mineshaft canary."

"With knowledge of its genome, and using both field sampling and laboratory studies, the possible effects of environmental agents on cellular and molecular processes can be resolved and linked to similar processes in humans."

The scientists learned that of all sequenced invertebrate genomes so far, Daphnia shares the most genes with humans.

Daphnia's gene expression patterns change depending on its environment, and the patterns indicate what state its cells are in.

A water flea bobbing in water containing a chemical pollutant will tune-up or tune-down a suite of genes differently than its sisters accustomed to water without the pollutant, for example.

The health effects of most industrially produced compounds in the environment are unknown, because current testing procedures are too slow, too costly, and unable to indicate the causes for their effects on animals, including humans.

Over the course of the project, the Daphnia Genomics Consortium has grown from a handful of founding members to more than 450 investigators around the globe.

"Assembling so many experts around a shared research goal is no small feat," said Peter Cherbas, director of the CGB. "The genome project signals the coming-of-age of Daphnia as a research tool for investigating the molecular underpinnings of key ecological and environmental problems."

Colbourne agreed, adding, "New model systems rarely arrive on the scene with such clear and important roles to play in advancing a new field of science."

(Photo: Paul Hebert, University of Guelph)

National Science Foundation (NSF)


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Pigeons rely mainly on their olfactory sense when they navigate. Young pigeons learn to recognize environmental odours carried by the winds into the loft and to use these odours to find their way home from unfamiliar territory. Scientists from the Max Planck Institute for Ornithology in Radolfzell, Anna Gagliardo from the University of Pisa, and their colleagues at the University of Trient recently demonstrated that pigeons navigate more poorly with their right nostril blocked. This finding suggests that the left brain hemisphere, where olfactory information is processed, is of fundamental importance to the orientation and navigation of homing pigeons.

The amazing ability of pigeons to find their way to their home loft has been known for centuries. According to scientists, these birds possess a distinctive olfactory sense as well as a capacity for recognizing odours, which helps them to develop a kind of “scent map” of their surroundings. However, it seems that pigeons cannot smell similarly with both nostrils. Like humans, they can detect odours better through their right nostril.

Martin Wikelski from the Max Planck Institute for Ornithology in Radolfzell and Anna Gagliardo from the University of Pisa recently completed a study of 31 pigeons to determine how the birds’ orientation would be affected if the they were unable to smell through their right nostril. The scientists inserted small, rubbery, removable plugs into the left nostril of some of the birds and into the right nostril of others. All the pigeons were hand-raised in the area around of Pisa. After fixing small GPS data loggers on the pigeons’ backs, the researchers released the pigeons near Cigoli, a Tuscan village 42 km away from the birds’ home.

Based on the GPS data they collected, the scientists found that the pigeons that could not breathe through their right nostril took a more tortuous route. They stopped more often, and spent more time exploring the surroundings of the stopover sites than those birds that could smell with their right nostril. “We suppose that these birds had to stop to gather additional information about their surroundings because they could not navigate by their olfactory sense,” says Anna Gagliardo. “This behaviour not only indicates that an asymmetry exists in the perception and processing of odours between the left and the right olfactory system; it also shows that the right nostril apparently plays an important role in processing olfactory information in the left hemisphere that is useful for navigation.” How the pigeons’ brains process these sensory perceptions, and why this processing is asymmetric, the researchers do not yet know.

(Photo: © Guiseppe Di Lieto)



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After a decade of experimental development, data-taking, and analysis, an international research team led by scientists from Boston University and the University of Illinois has announced a new value for the muon lifetime.

The new lifetime measurement—the most precise ever made of any subatomic particle—makes possible a new determination of the strength of the weak nuclear force. Experiments for this research were conducted using the proton accelerator facility of the Paul Scherrer Institute (PSI) in Villigen, Switzerland. The results were published in the January 25, 2011 issue of the journal Physical Review Letters.

The weak force is one of the four fundamental forces of nature. Although rarely encountered in everyday life, the weak force is at the heart of many elemental physical processes, including those responsible for making the sun shine. All four of the fundamental forces are characterized by coupling constants, which describe their strength. The famous constant G, in Newton’s law of gravitation, determines the gravitational attraction between any two massive objects. The fine structure constant determines the strength of the electrostatic force between charged particles. The coupling constant for the weak interactions, known as the Fermi constant, is also essential for calculations in the world of elementary particles. Today, physicists regard the weak and the electromagnetic interaction as two aspects of one and the same interaction. Proof of that relationship, established in the 1970s, was an important breakthrough in our understanding of the subatomic world.

The new value of the Fermi constant was determined by an extremely precise measurement of the muon lifetime. The muon is an unstable subatomic particle which decays with a lifetime of approximately two microseconds (two millionths of a second). This decay is governed by the weak force only, and the muon's lifetime has a relatively simple relationship to the strength of the weak force. "To determine the Fermi constant from the muon lifetime requires elegant and precise theory, but until 1999, the theory was not as good as the experiments," says David Hertzog, professor of physics at the University of Washington. (At the time of the experiment, Hertzog was at the University of Illinois.) “Then, several breakthroughs essentially eliminated the theoretical uncertainty. The largest uncertainty in the Fermi constant determination was now based on how well the muon lifetime had been measured."

The MuLan (Muon Lifetime Analysis) experiment used muons produced at PSI’s proton accelerator—the most powerful source of muons in the world and the only place where this kind of experiment can be done. "At the heart of the experiment were special targets that caught groups of positively charged muons during a ‘muon fill period,’" says PSI’s Bernhard Lauss. "The beam was then rapidly switched off, leaving approximately 20 muons in the target. Each muon would eventually decay, typically ejecting an energetic positron—a positively charged electron—to indicate its demise. The positrons were detected using a soccer-ball shaped array of 170 detectors, which surrounded the target." Boston University physics professor Robert Carey adds, "We repeated this procedure for 100 billion muon fills, accumulating trillions of individual decays. By the end, we had recorded more than 100 terabytes of data, far more than we could handle by ourselves. Instead, the data was stored and analyzed at the National Center for Supercomputing Applications (NCSA) in Illinois." A distribution of how long each muon lived before it decayed was created from the raw data and then fit to determine the mean lifetime: 2.1969803 ±0.0000022 microseconds. The uncertainty is approximately 2 millionths of a millionth of a second - a world record.

Boston University


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Synchrotron X-ray investigation of a fossilised snake with legs is helping scientists to better understand how in the course of evolution snakes have lost their legs, and whether they evolved from terrestrial lizards or from reptiles living in the oceans. New 3-D X-ray images reveal that the internal architecture of the ancient snake’s leg bones resemble those of modern terrestrial lizard legs. The results are published on 8 February in the Journal of Vertebrate Paleontology.

A novel X-ray imaging technology is helping scientists to better understand how in the course of evolution snakes have lost their legs. The researchers hope that the new data will help to resolve a heated debate about the origin of snakes: whether they evolved from a terrestrial lizard or from one that lived in the oceans. New, detailed 3-D images reveal that the internal architecture of an ancient snake’s leg bones strongly resembles those of modern terrestrial lizard legs. The results are published in the 8 February issue of the Journal of Vertebrate Paleontology.

The team of researchers was led by Alexandra Houssaye from Museum National d'Histoire Naturelle (MNHN) and CNRS in Paris, France, and included scientists from the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, where the X-ray imaging was performed, and the Karlsruhe Institute of Technology (KIT), Germany, where a sophisticated technique and a dedicated instrument to take the images were developed.

Only three specimens exist of fossilised snakes with preserved leg bones. Eupodophis descouensi, the ancient snake studied in this experiment, was discovered ten years ago in 95-million-year-old rocks in Lebanon. About 50 cm long overall, it exhibits a small leg, about 2 cm long, attached to the animal’s pelvis. This fossil is key to understanding the evolution of snakes, as it represents an intermediate evolutionary stage when ancient snakes had not yet completely lost the legs they inherited from earlier lizards. Although the fossil exhibits just one leg on its surface, a second leg was thought to be concealed in the stone, and indeed this leg was revealed in full detail thanks to synchrotron X-rays.

The high-resolution 3-D images, in particular the fine details of the buried small leg, suggest that this species lost its legs because they grew more slowly, or for a shorter period of time. The data also reveal that the hidden leg is bent at the knee and has four ankle bones but no foot or toe bones.

"The revelation of the inner structure of Eupodophis hind limbs enables us to investigate the process of limb regression in snake evolution," says Alexandra Houssaye.

The scientists used synchrotron laminography, a recent imaging technique specially developed for studying large, flat samples. It is similar to the computed tomography (CT) technique used in many hospitals, but uses a coherent synchrotron X-ray beam to resolve details a few micrometres in size — some 1000 times smaller than a hospital CT scanner. For the new technique, the fossil is rotated at a tilted angle in a brilliant high-energy X-ray beam, with thousands of two-dimensional images recorded as it makes a full 360-degree turn. From these individual images, a high-resolution, 3-D representation is reconstructed, which shows hidden details like the internal structure(s) of the legs.

"Synchrotrons, these enormous machines, allow us to see microscopic details in fossils invisible to any other techniques without damage to such invaluable specimens," says Paul Tafforeau of the ESRF, a co-author of the study.

(Photo: A. Houssaye)


Wednesday, February 23, 2011

Rare insect fossil reveals 100 million years of evolutionary stasis

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Researchers have discovered the 100 million-year-old ancestor of a group of large, carnivorous, cricket-like insects that still live today in southern Asia, northern Indochina and Africa. The new find, in a limestone fossil bed in northeastern Brazil, corrects the mistaken classification of another fossil of this type and reveals that the genus has undergone very little evolutionary change since the Early Cretaceous Period, a time of dinosaurs just before the breakup of the supercontinent Gondwana.

The findings are described in a paper in the open access journal ZooKeys.

“Schizodactylidae, or splay-footed crickets, are an unusual group of large, fearsome-looking predatory insects related to the true crickets, katydids and grasshoppers, in the order Orthoptera,” said University of Illinois entomologist and lead author Sam Heads, of the Illinois Natural History Survey. “They get their common name from the large, paddle-like projections on their feet, which help support their large bodies as they move around their sandy habitats, hunting down prey.”

Although the fossil is distinct from today’s splay-footed crickets, its general features differ very little, Heads said, revealing that the genus has been in a period of “evolutionary stasis” for at least the last 100 million years.

Other studies have found that the region where the fossil was found was most likely an arid or semi-arid monsoonal environment during the Early Cretaceous Period, Heads said, “suggesting that the habitat preferences of Schizodactylus have changed little in over 100 million years.”

Léa Leuzinger, a graduate student at the University of Fribourg, Switzerland, is a co-author on the study.

(Photo: Hwaja Goetz)

University of Illinois

Not Just for Raincoats

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Researchers from Northwestern University and the Massachusetts Institute of Technology (MIT) have studied individual water droplets and discovered a miniature version of the “water hammer,” an effect that produces the familiar radiator pipe clanging in older buildings.

In piping systems, the water hammer occurs when fluid is forced to stop abruptly, causing huge pressure spikes that can rupture pipe walls. Now, for the first time, the researchers have observed this force on the scale of microns: such pressure spikes can move through a water droplet, causing it to be impaled on textured superhydrophobic surfaces, even when deposited gently.

This insight of how droplets get stuck on surfaces could lead to the design of more effective superhydrophobic, or highly water-repellant, surfaces for condensers in desalination and steam power plants, de-icing for aircraft engines and wind turbine blades, low-drag surfaces in pipes and even raincoats. In certain cases, improved surfaces could improve energy efficiency on many orders of magnitude. (About half of all electricity generated in the world comes from steam turbines.)

The research is published by the journal Physical Review Letters.

“We want to design surface textures that will cause the water to really hate those surfaces,” said Neelesh A. Patankar, associate professor of mechanical engineering at Northwestern’s McCormick School of Engineering and Applied Science. “Improving current hydrophobic materials could result in a 60 percent drag reduction in some applications, for example.”

Patankar collaborated with Kripa K. Varanasi, the d’Arbeloff Assistant Professor of Mechanical Engineering at MIT. The two are co-corresponding authors of the paper. Patankar initiated this study in which he and Varanasi led the analytical work, and the experiments were conducted at MIT in Varanasi’s lab. Other co-authors are MIT mechanical engineering graduate students Hyuk-Min Kwon and Adam Paxson.

In designing superhydrophobic surfaces, one goal is to produce surfaces much like the natural lotus leaf. Water droplets on these leaves bead up and roll off easily, taking any dirt with them. Contrary to what one might think, the surface of the leaves is rough, not smooth. The droplets sit on microscopic bumps, as if resting on a bed of nails.

“If a water droplet impales the grooves of this bumpy texture, it becomes stuck instead of rolling off,” Patankar said. “Such transitions are well known for small static droplets. Our study shows that the impalement of water is very sensitive to the dynamic ‘water hammer’ effect, which was not expected.”

To show this, the researchers imaged millimeter-scale water droplets gently deposited onto rough superhydrophobic surfaces. (The surfaces were made of silicon posts, with spacing from post edge to post edge ranging from 40 to 100 microns, depending on the experiment.) Since these drops were on the millimeter scale and being deposited gently, prior understanding was to assume that gravitational force is not strong enough to push the water into the roughness grooves. The Northwestern and MIT researchers are the first to show this is not true.

They observed that as a droplet settles down on the surface (due to the drop’s own weight) there is a rapid deceleration in the drop that produces a brief burst of high pressure, sending a wave through the droplet. The droplet is consequently pinned on the rough surface. That’s the powerful mini water hammer effect at work.

By understanding the underlying physics of this transition, the study reveals that there is actually a window of droplet sizes that avoid impalement. Although focused on drop deposition, this idea is quite general and applies to any scenario where the water velocity is changing on a short (less than a millisecond) time scale. This insight can lead to the design of more robust superhydrophobic surfaces that can resist water impalement even under the dynamic conditions typical in industrial setups.

“One way to reduce impalement is to design a surface texture that results in a surface that sustains extremely high pressures,” Patankar said. “It is the length scale of the roughness that is important.” To resist impalement, the height of a bump and the distance between bumps need to be just right. Hundreds of nanometer scale roughness can lead to robust surfaces.

“Our ultimate goal,” he added, “is the invention of textured surfaces such that a liquid in contact with it will, at least partially, vaporize next to the surface -- or sustain air pockets -- and self-lubricate. This is similar to how an ice skater glides on ice due to a cushion of thin lubricating liquid film between the skates and the ice. A critical step is to learn how to resist impalement of water on the roughness. Our work on water hammer-induced impalement is a crucial advance toward that goal of ultra-slippery vapor stabilizing surfaces.”

(Photo: Northwestern U.)

Northwestern University

Liquids scanner for airport security

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Air passengers one day may be able to carry their soaps, shampoo and bottled water onto the plane again, thanks to technology originally developed at UC Davis to check the quality of wine.

The U.S. Department of Homeland Security’s Science and Technology Directorate recently awarded a contract to a Denver-based defense firm to develop a magnetic resonance scanner that could be placed in airports and used to check bottles and cans for explosives without opening them. A prototype of the machine will be constructed in the laboratory of Matthew Augustine, the UC Davis chemistry professor who invented and patented the technology, with an initial allocation of $800,000.

The technology is similar to the magnetic resonance imaging machines used in medical scanning. It employs a pulse of radio waves and a strong magnetic field to extract a signal that shows the chemical structure of the sample.

Augustine began experimenting with the technology some years ago to check bottles of wine for spoilage without opening them.

That technology was patented in 2002 and licensed by UC Davis to Madison Avenue Management Inc., which set up a subsidiary company, Winescanner Inc., to commercialize it.

After a thwarted 2006 plot in which terrorists planned to carry liquid explosives on board at least 10 transatlantic airliners, Augustine started looking into whether magnetic resonance could be used to identify more than bad wine.

"I'm a tinkerer, I like to build stuff," Augustine said.

Early tests showed that his wine-analysis technique could distinguish gasoline or other dangerous liquids from toothpaste or other innocuous ones.

But the challenge was to design a system suitable for use in airports: relatively small, easy and quick to use, and capable of scanning containers in a wide range of sizes and shapes, from lipsticks to water bottles.

Arriving at such a design involved careful trade-offs between high-frequency radio waves, which give the best information about chemical structures but are blocked by metal, and lower-frequency waves that could pass through a soda can.

University of California, Davis


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Despite decades of research and billions of dollars, cancer remains a major killer, with an uncanny ability to evade both the body’s defenses and medical intervention. Now an Arizona State University scientist believes he has an explanation.

“Cancer is not a random bunch of selfish rogue cells behaving badly, but a highly-efficient pre-programmed response to stress, honed by a long period of evolution,” claims professor Paul Davies, director of the BEYOND Center for Fundamental Concepts in Science at ASU and principal investigator of a major research program funded by the National Cancer Institute designed to bring insights from physical science to the problem of cancer.

In a paper published online Feb. 7 in the UK Institute of Physics journal Physical Biology, Davies and Charles Lineweaver from the Australian National University draw on their backgrounds in astrobiology to explain why cancer cells deploy so many clever tricks in such a coherent and organized way.

They say it’s because cancer revisits tried-and-tested genetic pathways going back a billion years, to the time when loose collections of cells began cooperating in the lead-up to fully developed multicellular life. Dubbed by the authors “Metazoa 1.0,” these early assemblages fell short of the full cell and organ differentiation associated with modern multicellular organisms – like humans.

But according to Davies and Lineweaver, the genes for the early, looser assemblages – Metazoa 1.0 – are still there, forming an efficient toolkit. Normally it is kept locked, suppressed by the machinery of later genes used for more sophisticated body plans. If something springs the lock, the ancient genes systematically roll out the many traits that make cancer such a resilient form of life – and such a formidable adversary.

“Tumors are a re-emergence of our inner Metazoan 1.0, a throwback to an ancient world when multicellular life was simpler,” says Davies. “In that sense, cancer is an accident waiting to happen.”

If Davies and Lineweaver are correct, then the genomes of the simplest multicellular organisms will hide clues to the way that cancer evades control by the body and develops resistance to chemotherapy. And their approach suggests that a limited number of genetic pathways are favored by cells as they become progressively genetically unstable and malignant, implying that cancer could be manageable by a finite suite of drugs in the coming era of personalized medicine.

“Our new model should give oncologists new hope because cancer is a limited and ultimately predictable atavistic adversary,” says Lineweaver. “Cancer is not going anywhere evolutionarily; it just starts up in a new patient the way it started up in the previous one.”

The authors also believe that the study of cancer can inform astrobiology. “It’s not a one-way street,” says Davies. “Cancer can give us important clues about the nature and history of life itself.”

(Photo: Vivek Nandakumar, Center for Biosignatures Discovery Automation, Biodesign Institute, Arizona State University)

Arizona State University


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Recent extreme weather events as far as Australia and Africa are being fueled by a climate phenomenon known as La Niña—or “the girl” in Spanish. La Niña has also played a minor role in the recent cold weather in the Northeast U.S.

The term La Niña refers to a period of cooler-than-average sea-surface temperatures in the Equatorial Pacific Ocean that occurs as part of natural climate variability. This situation is roughly the opposite of what happens during El Niño (“the boy”) events, when surface waters in this region are warmer than normal. Because the Pacific is the largest ocean on the planet, any significant changes in average conditions there can have consequences for temperature, rainfall and vegetation in distant places.

Scientists at the International Research Institute for Climate and Society (IRI), part of Columbia’s Earth Institute, expect moderate-to-strong La Niña conditions to continue in the tropical Pacific, potentially causing additional shifts in rainfall patterns across many parts of the world in months to come.

These shifts, combined with socioeconomic conditions and other factors, are making some countries more vulnerable. However, La Niña and El Niño conditions actually allow for more accurate seasonal forecasts and help better predict extreme drought or rainfall in some areas. That’s because they affect global atmospheric circulation patterns in known ways, and scientists can use this knowledge to help societies prepare better, issue early warnings and reduce any negative impacts associated with them.

"Based on current observations and on predictions from models, we see at least a 90 percent chance that La Niña conditions will continue through March," said IRI's chief forecaster, Tony Barnston.

Climate scientists have found La Niña's fingerprints on a number of extreme weather events such as the devastating flood that occurred in Pakistan in 2010, as well as flooding in West Africa, South Africa and most recently in Queensland, Australia, where an area equal to the combined size of France and Germany was underwater. La Niña is also to blame for Cyclone Yasi, one of the strongest to hit Australia, which came ashore on Feb. 2. Cyclone Yasi is the second most damaging Australian cyclone on record after Cyclone Tracy, which struck in 1974.

But La Niña isn't to blame for the recent severe weather affecting the Northeast. Winter weather for these regions is often driven not by La Niña but by large-scale weather patterns over the U.S., the northern Atlantic Ocean and the Arctic. These are often short-term, and are generally predictable only a week or so in advance. They are the culprits responsible for the dip in temperatures and spike in snow storms in the Midwest and Northeast.

In addition to extreme rainfall, La Niña can lead to drought conditions. Currently in East Africa, it has caused drier-than-usual weather, sparking food-security concerns in areas lacking irrigation, including parts of Somalia, Kenya, Ethiopia and Tanzania. Parts of South America, Asia and the southern U.S. may also see lower rainfall for the first quarter of 2011.

Since 1950, the world has experienced six major La Niña events, wreaking havoc in countries around the world. In 2000, for example, floods associated with La Niña affected 400,000 people in southern Africa, caused at least 96 deaths and left 32,000 homeless.

La Niña conditions typically persist for 9 to 12 months, peaking sometime during the end of the year. But 2010 was a lively year for climate scientists: For the first four months of this year, El Niño conditions prevailed in the tropical Pacific, but that quickly changed, and by June, a La Niña pattern had emerged.

"Last year's transition from El Niño to La Niña was about the most sudden we've ever had," Barnston said. "When we had rapid flips like this in the past, we sometimes ended up having a two-year La Niña, such as right after the El Niño episodes of 1972 to 1973 and 1997 to 1998."

Barnston cautions that the likelihood of this happening with the current La Niña is unknown. "Even if we do have a second year of La Niña developing in northern summer 2011, we expect at least a brief return to neutral conditions from May to July of 2011."

(Photo: NASA)

University of Columbia


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It's an incendiary topic in academia -- the pervasive belief that women are underrepresented in science, math and engineering fields because they face sex discrimination in the interviewing, hiring, and grant and manuscript review processes. In a study published Feb. 7 in the journal Proceedings of the National Academy of Sciences, Cornell social scientists say it's just not true.

It's not discrimination in these areas, but rather, differences in resources attributable to career and family-related choices that set women back in STEM (science, technology, engineering and math) fields, say Stephen J. Ceci, the H.L. Carr Professor of Developmental Psychology, and Wendy M. Williams, professor of human development and director of the Cornell Institute for Women in Science, both in Cornell's College of Human Ecology.

The "substantial resources" universities expend to sponsor gender-sensitivity training and interviewing workshops would be better spent on addressing the real causes of women's underrepresentation, Ceci and Williams say, through creative problem-solving and policy changes that respond to differing "biological and social realities" of the sexes.

The researchers analyzed the scientific literature in which women and men competed for publications, grants or jobs in these fields. They found no systematic evidence of sex discrimination in interviewing, hiring, reviewing or funding when men and women with similar resources -- such as teaching loads and research support -- were compared.

"We hear often that men have a better chance of getting their work accepted or funded, or of getting jobs, because they're men," Williams said. "Universities expend money and time trying to combat this rampant alleged discrimination against women in the hope that by doing so universities will see the numbers of women STEM scientists increase dramatically over coming years."

The data show that women scientists are confronted with choices, beginning at or before adolescence, that influence their career trajectories and success. Women who prioritize families and have children sometimes make "lifestyle choices" that lead them to take positions, such as adjunct or part-time appointments or jobs at two-year colleges, offering fewer resources and chances to move up in the ranks. These women, however, are not held back by sex discrimination in hiring or in how their scholarly work is evaluated. Men with comparably low levels of research resources fare equivalently to their female peers. Although women disproportionately hold such low-resource positions, this is not because they had their grants and manuscripts rejected or were denied positions at research-intensive universities due to their gender.

Also, females beginning before adolescence often prefer careers focusing on people, rather than things, aspiring to be physicians, biologists and veterinarians rather than physicists, engineers and computer scientists. Efforts to interest young girls in these math-heavy fields are intended to ensure girls do not opt out of inorganic fields because of misinformation or stereotypes.

Also, fertility decisions are key because the tenure system has strong disincentives for women to have children -- a factor in why more women in academia are childless than men. Implementation of "flexible options" to enhance work-family balance may help to increase the numbers of women in STEM fields, the researchers say.

As long as women make the choice and "are satisfied with the outcomes, then we have no problem," they write in the paper. "However, to the extent that these choices are constrained by biology and/or society, and women are dissatisfied with the outcomes, or women's talent is not actualized, then we most emphatically have a problem." The solution will only be possible if society focuses on changing the women's non-optimal choices and addressing unique challenges faced by female STEM scientists with children, the researchers say.

(Photo: Cornell U.)

Cornell University

Tuesday, February 22, 2011

Allergy Treatment Helps Kids Tolerate Some Peanuts

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A peanut solution given under the tongue can desensitize a child's deadly peanut allergies, but further testing will be needed to determine if it may permanently eliminate their reactions to the foods, according to researchers from Duke University Medical Center.

In a double-blind, placebo-controlled study, Duke researchers built up tolerance to the allergen in 11 children with a year of small but escalating daily doses of peanut. The therapy allowed the children to tolerate 20 times more peanut protein.

These protocols were done in a clinical setting with close observation and emergency resources close at hand.

“A treatment like this means that some families won’t need to be as concerned about their children taking a bite of something that has peanut in it and could cause a life-threatening reaction,” said Wesley Burks, MD, chief of the Division of Pediatric Allergy and Immunology at Duke and senior author of the study. “It would really provide them a margin of safety.”

This form of therapy, called sublingual immunotherapy, is different from Burks’ previously published research on oral immunotherapy, which involves eating milligrams to grams of peanuts in the form of flour mixed in another food, such as applesauce. That research continues to help kids tolerate peanuts without reactions, and Burks is looking at how the therapy may help resolve their allergies.

Burks’ new research builds on a therapy that has been helpful to people with allergic rhinitis and asthma, but has not been studied extensively as a therapy for food allergy.

More than three million Americans have peanut or tree nut allergies and fewer than 20 percent will outgrow the allergy without therapy. Currently, there is no treatment for the disease. Once a diagnosis is made, physicians have to try to help the family avoid the food, which is not a perfect plan because accidental exposure can still happen.

That is one reason Burks and his team are trying to develop a new, successful therapy for peanut allergy sufferers.

“Ideally we want to eliminate the allergy,” Burks said. “But, we are not there yet.”

The study included 18 children who completed 12 months of dosing. One group (11 children) received the liquid peanut concentration, which was held under the tongue for one or two minutes and then swallowed.

The other group (seven children) received the placebo. The dose started at 0.25 micrograms of peanut protein administered in clinic and was increased biweekly by 25 to 100 percent until 2,000 micrograms was reached. In the time between the biweekly doses in the clinic, the children took daily doses of the previously administered dose at home. The 2,000 microgram dose was continued for six months.

After a year of dosing, the children on treatment tolerated significantly more peanuts when they were challenged. They tolerated the equivalent of six to seven peanuts compared to those that received placebo and tolerated less than one peanut.

“We were able to raise the threshold for the amount of peanuts these kids could tolerate,” Burks said. “But, we are not ready to take this approach to clinical practice,” he cautioned. “It’s not a long-term cure. That part of the process is still being studied now.”

Those that were on treatment are continuing and those that were on placebo have entered the treatment phase. Both groups will be followed three or four more years to determine if it’s feasible to eliminate their allergy.

“The good news is we have successfully helped these kids tolerate about five peanuts and that means accidental ingestion is less of a hazard,” Burks said. “Most kids with peanut allergies are not going to accidentally eat five peanuts and most reactions from accidental ingestions occur from just a trace of a peanut, well below the study groups’ new threshold.”

Duke University Medical Center

Researchers link declining litter sizes and loss of sea ice

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University of Alberta researchers have linked the reproductive ecology of polar bears in Hudson Bay with declining litter sizes and loss of sea ice.

“Projected reductions in the number of newborn cubs are a significant threat to the western Hudson Bay polar-bear population,” said lead researcher Péter Molnár, from the Department of Biological Sciences. “If climate change continues unabated the viability of the species across much of the Arctic will be in question.”

Molnar and U of A colleagues Andrew Derocher and Mark Lewis used data collected beginning in the 1990s to analyze how long, during the polar bear’s hunting season, Hudson Bay is frozen over and the amount of energy pregnant females can store up before denning and birthing.

“An early spring-ice break up reduces the hunting season, making it difficult for pregnant females to even support themselves, let alone give birth to and raise cubs,” said Derocher.

Pregnant polar bears take to a maternity den for up to eight months and during this time no food is available and they survive on their fat stores.

In the early 1990s, researchers estimate, 28 per cent of energy-deprived pregnant polar bears in the Hudson Bay region failed to produce a litter. Researchers say energy-deprived pregnant females will either not enter a maternity den or they will naturally abort.

Using mathematical modeling to estimate the energetic impacts of a shortened hunting season, the research team calculated the following scenarios:

· If spring break up in Hudson Bay comes one month earlier than in the 1990s, 40 to 73 per cent of pregnant female polar bears will not reproduce.

· If the ice breaks up two months earlier than in the 1990s, 55 to a full 100 per cent of all pregnant female polar bears in western Hudson Bay will not have a cub.

The polar-bear population of western Hudson Bay is currently estimated to be around 900, which is down from 1,200 bears in the past decade. The number of polar bears across the Arctic is estimated to be between 20,000 and 25,000.

“Because the Hudson Bay polar bears are the most southerly population, they are the first to be affected by the global-warming trend,” said Molnar. “However, if temperatures across the Arctic continue to rise, much of the global population of polar bears will be at risk.”

(Photo: U. Alberta)

University of Alberta

Engineers and Blue Peter make hair-raising contraption to put fairytale to the test

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A team of engineers from Imperial College London have developed a contraption made of human hair, enabling presenters from the world’s longest running children’s television program to test the theory behind a fairytale.

The producers from the children’s television program Blue Peter approached Imperial’s Dr Andrew Phillips, asking him and senior technician Ron Millward to help them to build a rig that would enable them to test the strength of hair. The TV show wanted to see if hair could support the weight of a human, as it did in the fairytale “Rapunzel”. In the fairytale, Rapunzel throws her extremely long hair out of her window, enabling a prince to use it like rope and climb into her room at the top of a tower to attempt a rescue.

Dr Andrew Phillips, from the Department of Civil and Environmental Engineering at the College, said:

“Part of the reason for working with Blue Peter on this project is that we wanted to show a young audience that our bodies manufacture really incredible materials like hair, which has some amazing properties. For instance, hair can be as strong as aluminium and a full head of hair could support up to 12 tonnes in weight.”

In the CBBC video clip, watch the demonstration and see what happens to the Blue Peter presenter when some of the strands are snipped off.

The main problem that the team had to overcome when they were building the wooden rig was finding a way to fix the strands of hair securely. The team borrowed an old technique, normally used to make ropes, which involved them splaying the hair out and then gluing it into conical holes that were bored into the rig. They then hammered blocks of wood called ‘bungs’ into the conical holes, ensuring that the hair was held in place securely.

The team also plaited the hair, which reinforced its strength and ensured that the weight was distributed evenly across the rig . The researchers also carried out tests in the lab, using lead weights, to ensure that the device would not fall apart during the demonstration on TV.

Dr Phillips, whose research focuses on developing computer programs that model how the human body works, added: “This project provided us with a wonderful opportunity to demonstrate to children how fascinating engineering can be. It is not every day that a fairytale provides the impetus for a project that helps a young audience to see how engineering can be used to solve problems and explain things.”

After Dr Phillips’s team built the harness, it was driven to the Blue Peter studios in BBC Television Centre, where presenter Andy Akinwolere was suspended in the harness one metre above the ground.

At the end of the TV experiment, the Imperial researchers were awarded Blue Peter badges for their efforts.

(Photo: ICL)

Imperial College London




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