Friday, September 11, 2009


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Results of the first study evaluating the use of human urine mixed with wood ash as a fertilizer for food crops has found that the combination can be substituted for costly synthetic fertilizers to produce bumper crops of tomatoes without introducing any risk of disease for consumers. The study appears in the current issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

In the study, Surendra Pradhan and colleagues point out that urine, a good source of nitrogen, has been successfully used to fertilize cucumber, corn, cabbage, and other crops. Only a few studies, however, have investigated the use of wood ash, which is rich in minerals and also reduces the acidity of certain soils. Scientists have not reported on the combination of urine and wood ash, they say.

The new study found that plants fertilized with urine produced four times more tomatoes than nonfertilized plants and as much as plants given synthetic fertilizer. Urine plus wood ash produced almost as great a yield, with the added benefit of reducing the acidity of acid soils. "The results suggest that urine with or without wood ash can be used as a substitute for mineral fertilizer to increase the yields of tomato without posing any microbial or chemical risks," the report says.

(Photo: Wikimedia Commons)

American Chemical Society


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Chimpanzees in the Congo have developed specialised 'tool kits' to forage for army ants, reveals new research published in the American Journal of Primatology. This not only provides the first direct evidence of multiple tool use in this context, but suggests that chimpanzees have developed a 'sustainable' way of harvesting food.

A team from the Goualougo Triangle Ape Project, led by Dr Crickette Sanz, studied several communities of chimpanzee throughout the Nouabalé-Ndoki national park in the Republic of Congo. After spending a collective 111 months in the Goualougo Triangle, the team recovered 1,060 tools and collected 25 video recordings of chimpanzees using them to forage for army ants.

"The use of tool sets is rare and has most often been observed in great apes," said Sanz. "Until now there have been no reports of regular use of more than one type of tool to prey upon army ants."

It is already known that chimpanzees use tools when foraging for honey or collecting termites. However the variation in techniques and the relationship between the ants and the chimpanzees has perplexed scientists for decades.

"In other studies, based across Africa, chimpanzees have been seen to prey on army ants both with and without tools," said Sanz, "and it was inexplicable why some chimpanzees used different techniques to gather the same prey."

The average number of tools recovered by the team at each site was 3.37, while 36% of recovered tools sets contained two types of tools, nest perforating tools and ant-dipping probes. Ant-dipping probes are the most commonly observed method of catching army ants. The chimpanzee inserts a probe into a nest or column of ants and gathers the individuals who stream up the tool. The perforating tools on the other hand are used to open nests so the chimpanzee can gather the ants within.

While the tools sets observed during this study were similar to other recorded tools, this research suggests that chimpanzees are selecting tools depending on the characteristics of the ant species they are foraging. There are several varying species of ants found throughout the triangle, but their characteristics can be divided into two categories, 'epigaeic' or 'intermediate'.

Epigaeic ants have longer legs so can run faster and can inflict a more painful bite. They forage on the ground and in the vegetation and when attacked the workers counter-attack in large swarms. Intermediate species forage only in the leaf litter and withdraw into underground tunnels or into the leaf litter when attacked.

Chimpanzees that harvest ants simply by raking a nest open with their hands cause a massive counter-attack from the ants. This results not only in bites but the attack may provoke the ants to migrate and build a new nest at a different location.

However, by using the perforation tools the chimps can entice the ants out and can allow the insertion of the second tool for dipping. This not only reduces the ant's aggressive behaviour but may also be a 'sustainable harvesting' technique as the ants will stay in that location allowing the chimpanzees to revisit this renewable source of food.

It also appears that chimpanzees practise recycling by recognising tool forms and re-using tools which have been discarded by other individuals during previous visits.

"It has only recently been discovered that these particular chimpanzees use several different types of tool sets which could be their cultural signature of sorts," concluded co-author Dr. David Morgan. "There is an urgency to learn about these behaviours as the existence of the apes in the Congo Basin is threatened by commercial logging, bushmeat hunting, and emerging diseases."



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Scientists using a continent-wide array of radio telescopes have made an extremely precise measurement of the curvature of space caused by the Sun's gravity, and their technique promises a major contribution to a frontier area of basic physics.

"Measuring the curvature of space caused by gravity is one of the most sensitive ways to learn how Einstein's theory of General Relativity relates to quantum physics. Uniting gravity theory with quantum theory is a major goal of 21st-Century physics, and these astronomical measurements are a key to understanding the relationship between the two," said Sergei Kopeikin of the University of Missouri.

Kopeikin and his colleagues used the National Science Foundation's Very Long Baseline Array (VLBA) radio-telescope system to measure the bending of light caused by the Sun's gravity to an accuracy of 0.03 percent. With further observations, the scientists say their precision technique can make the most accurate measure ever of this phenomenon.

Bending of starlight by gravity was predicted by Albert Einstein when he published his theory of General Relativity in 1916. According to relativity theory, the strong gravity of a massive object such as the Sun produces curvature in the nearby space, which alters the path of light or radio waves passing near the object. The phenomenon was first observed during a solar eclipse in 1919.

Though numerous measurements of the effect have been made over the intervening 90 years, the problem of merging General Relativity and quantum theory has required ever more accurate observations. Physicists describe the space curvature and gravitational light-bending as a parameter called "gamma." Einstein's theory holds that gamma should equal exactly 1.0.

"Even a value that differs by one part in a million from 1.0 would have major ramifications for the goal of uniting gravity theory and quantum theory, and thus in predicting the phenomena in high-gravity regions near black holes," Kopeikin said.

To make extremely precise measurements, the scientists turned to the VLBA, a continent-wide system of radio telescopes ranging from Hawaii to the Virgin Islands. The VLBA offers the power to make the most accurate position measurements in the sky and the most detailed images of any astronomical instrument available.

The researchers made their observations as the Sun passed nearly in front of four distant quasars -- faraway galaxies with supermassive black holes at their cores -- in October of 2005. The Sun's gravity caused slight changes in the apparent positions of the quasars because it deflected the radio waves coming from the more-distant objects.

The result was a measured value of gamma of 0.9998 +/- 0.0003, in excellent agreement with Einstein's prediction of 1.0.

"With more observations like ours, in addition to complementary measurements such as those made with NASA's Cassini spacecraft, we can improve the accuracy of this measurement by at least a factor of four, to provide the best measurement ever of gamma," said Edward Fomalont of the National Radio Astronomy Observatory (NRAO). "Since gamma is a fundamental parameter of gravitational theories, its measurement using different observational methods is crucial to obtain a value that is supported by the physics community," Fomalont added.

(Photo: NRAO)

The National Radio Astronomy Observatory


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Recent archaeological discoveries from far-flung corners of China are forcing scientists to reconsider the origins of ancient Chinese civilization – and a new crop of young archaeologists are delving into the modern nation's roots. In the August 21 issue of the journal Science, a group of articles by Science news writer Andrew Lawler explore how, over several millennia, the most populous and economically vibrant nation in the world evolved from a much wider array of peoples and cultures than once imagined.

Lawler crisscrossed China recently for three weeks, traveling from the country's steamy southeastern plains to the rugged westernmost province of Xinjiang, interviewing dozens of archaeologists at a host of sites. This special news package puts a spotlight on how the various archaeological findings of the past decade are challenging what the Chinese people once thought about their country and themselves. As a construction boom continues to alter the physical face of the country – inadvertently uncovering vital clues to China's past, illuminating ancient trade routes and long-lost cultures – a new and more complex history of the Chinese people is emerging right before their very eyes.

The wealth of these recent archaeological discoveries demands a re-write of some history books – and young scholars are even now questioning the existence of a legendary Chinese dynasty, the Xia. Less willing to take ancient texts at face value than their predecessors, this new generation of Chinese researchers is relying on physical data – and more "Western" methods – in their attempts to accurately retrace Chinese history.

But looting and development threaten to destroy the country's heritage. In a land full of wealthy tombs and poor farmers, grave robbing has been an ancient tradition. China's current construction boom poses yet another threat to archaeological sites, though new laws are attempting to halt such damage. Those who destroy evidence of the country's rich history now face jail time and even the death penalty (though no one appears to have been executed for looting yet). Meanwhile, archaeologists are finding novel ways to work with developers and provincial governments to rescue at least some ancient sites from the destruction that comes with the country's economic growth.

"The exciting discoveries made recently across China, coupled with the country's fast-paced development, make this an opportune time to dig into new questions about China's origins, the state of its threatened ancient sites, and the increasing expertise of its archaeologists," says Andrew Lawler, author of the Science news package.

Lawler's special news package on Chinese archaeology covers the accidental discovery and later excavation of Jinsha, an ancient site located near downtown Chengdu in Sichuan, and about 600 miles (1000 kilometers) from the traditional center of Chinese civilization along the Yellow River. Long assumed to have been a cultural backwater, researchers have only recently gleaned the real history of Sichuan's surprisingly ancient and rich culture, which is thousands of years older than they had once believed. Now, thanks to a group of savvy archaeologists and their allies in the city government, Jinsha has become a museum, protected from looters and complete with adjacent land reserved for further archaeological digs in the future.

Another article by Lawler illuminates the earliest Silk Road which brought valued goods like bronze from the west and possibly the staple grain of ancient China, millet, to the west. These recent discoveries have led Chinese researchers to acknowledge significant outside influence on their ancient culture, breaking an old taboo put in place when China was largely closed to the outside world.

American Association for the Advancement of Science (AAAS)


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From giving directions to a stranger to cooking a meal for loved ones, sharing is an essential part of the human experience. A new study in the Journal of Consumer Research unravels the complexities of sharing and examines how changes in our culture affect sharing.

"Sharing is a fundamental consumer behavior that we have either tended to overlook or to confuse with commodity exchange and gift giving," writes author Russell Belk (York University, Toronto). In his study, Belk explores differences between sharing, gift giving, and exchanging marketplace commodities.

"Rather than absolute distinctions, I see these as categories that share fuzzy boundaries," writes Belk. "Although both sharing and gift-giving have some elements that often (but not always) make them more communal, loving, and caring than marketplace exchange, sharing differs from gift-giving in that it is non-reciprocal. The infant who receives his or her mother's nurturing care and sustenance does not incur a debt. Nor does the child who receives food, shelter, and love from parents receive an itemized bill upon leaving the nuclear family home."

Societal changes can affect the nature of sharing, notes Belk. Examples of threats to sharing may be the individualization of family phones and meals, the decline of free public education, and the shrinking of public broadcasting.

On the other hand, the Internet provides many healthy models for increased sharing. Belk notes that forums, bulletin boards, blogs, social networking sites, wikis, open-source software development projects, and websites where people share expertise, advice, and opinions all contribute to a sharing community.

Belk provides some suggestions for promoting sharing in today's world. "I suggest that two keys to promoting contemporary sharing are an expanded sense of self that embraces other people more than other things and a greater sense of 'sharing in,' where possessions are seen as ours rather than mine and yours," Belk concludes.

University of Chicago


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An international team of researchers has debunked one of astronomy's long held beliefs about how stars are formed, using a set of galaxies found with CSIRO’s Parkes radio telescope.

When a cloud of interstellar gas collapses to form stars, the stars range from massive to minute.

Since the 1950s astronomers have thought that in a family of new-born stars the ratio of massive stars to lighter ones was always pretty much the same — for instance, that for every star 20 times more massive than the Sun or larger, you’d get 500 stars the mass of the Sun or less.

“This was a really useful idea. Unfortunately it seems not to be true,” said team research leader Dr Gerhardt Meurer of Johns Hopkins University in Baltimore.

The different numbers of stars of different masses at birth is called the ‘initial mass function’ (IMF).

Most of the light we see from galaxies comes from the highest mass stars, while the total mass in stars is dominated by the lower mass stars.

By measuring the amount of light from a population of stars, and making some corrections for the stars’ ages, astronomers can use the IMF to estimate the total mass of that population of stars.

Results for different galaxies can be compared only if the IMF is the same everywhere, but Dr Meurer’s team has shown that this ratio of high-mass to low-mass newborn stars differs between galaxies.

For instance, small 'dwarf' galaxies form many more low-mass stars than expected.

To arrive at this finding, Dr Meurer’s team used galaxies from the HIPASS Survey (HI Parkes All Sky Survey) done with CSIRO’s Parkes radio telescope.

“All of these galaxies were detected with the Parkes telescope because they contain substantial amounts of neutral hydrogen gas, the raw material for forming stars, and this emits radio waves,” said CSIRO’s Dr Baerbel Koribalski, a member of Dr Meurer’s team.

Selecting galaxies on the basis of their neutral hydrogen gave a sample of galaxies of many different shapes and sizes, unbiased by their star formation history.

The astronomers measured two tracers of star formation, ultraviolet and H-alpha emissions, in 103 galaxies using NASA’s GALEX satellite and the 1.5-m CTIO optical telescope in Chile.

H-alpha emission traces the presence of very massive stars called O stars, which are born with masses more than 20 times that of the Sun.

The UV emission, traces both O stars and the less massive B stars — overall, stars more than three times the mass of the Sun.

Meurer’s team found that this ratio, of H-alpha to UV emission, varied from galaxy to galaxy, implying that the IMF also did, at least at its upper end.

Their work confirms tentative suggestions made first by Veronique Buat and collaborators in France in 1987, and then a more substantial study last year by Eric Hoversteen and Karl Glazebrook working out of Johns Hopkins and Swinburne Universities that suggested the same result.

“This is complicated work, and we’ve necessarily had to take into account many factors that affect the ratio of H-alpha to UV emission, such as the fact that B stars live much longer than O stars,” Dr Meurer said.

Dr Meurer’s team suggests the IMF seems to be sensitive to the physical conditions of the star-forming region, particularly gas pressure.

For instance, massive stars are most likely to form in high-pressure environments such as tightly bound star clusters.

The team’s results allow a better understanding of other recently observed phenomena that have been puzzling astronomers, such as variation of the ratio of H-alpha to ultraviolet light as a function of radius within some galaxies. This now makes sense as the stellar mix varying as the pressure drops with radius (just like the pressure varies with altitude on the Earth).

Importantly, the team also found that essentially all galaxies rich in neutral hydrogen seem to form stars.

“That means surveys for neutral hydrogen with radio telescopes will find star-forming galaxies of all kinds,” Dr Meurer said.

The Australian SKA Pathfinder, the next-generation radio telescope now being developed by CSIRO, will find neutral hydrogen gas in half a million galaxies, allowing a comprehensive examination of star-formation in the nearby universe.

(Photo: NASA/JPL-Caltech/JHU)

The Commonwealth Scientific and Industrial Research Organization (CSIRO)


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Researchers from Mind Research Network in Albuquerque used brain imaging and Tetris to investigate whether practice makes the brain efficient because it increases gray matter. For 30 minutes a day over a three-month period, 26 adolescent girls played Tetris, a computer game requiring a combination of cognitive skills. The girls completed both structural and functional MRI scans before and after the three-month practice period, as did girls in the control group who did not play Tetris. A structural MRI was used to assess cortical thickness, and a functional MRI was used to assess efficient activity.

The girls who practiced showed greater brain efficiency, consistent with earlier studies. Compared to controls, the girls that practiced also had a thicker cortex, but not in the same brain areas where efficiency occurred.

The areas of the brain that showed relatively thicker cortex were the Brodmann Area (BA) 6 in the left frontal lobe and BA 22 and BA 38 in the left temporal lobe. Scientists believe BA 6 plays a role in the planning of complex, coordinated movements. BA 22 and BA 38 are believed to be the part of the brain active in multisensory integration—or our brain's coordination of visual, tactile, auditory, and internal physiological information. Functional MRI (fMRI) showed greater efficiency after practice mostly in the right frontal and parietal lobes including BAs 32, 6, 8, 9, 46 and BA 40. These areas are associated with critical thinking, reasoning, and language and processing.

"One of the most surprising findings of brain research in the last five years was that juggling practice increased gray matter in the motor areas of the brain," said Dr. Rex Jung, a co-investigator on the Tetris study and a clinical neuropsychologist. "We did our Tetris study to see if mental practice increased cortical thickness, a sign of more gray matter. If it did, it could be an explanation for why previous studies have shown that mental practice increases brain efficiency. More gray matter in an area could mean that the area would not need to work as hard during Tetris play."

"We were excited to see cortical thickness differences between the girls that practiced Tetris and those that did not," said Dr. Richard Haier, a co-investigator in the study and lead author of a 1992 study that found practicing Tetris led to greater brain efficiency. "But, it was surprising that these changes were not where we saw more efficiency. How a thicker cortex and increased brain efficiency are related remains a mystery."

The researchers hope to continue this work with larger, more diverse samples to investigate whether the brain changes we measured revert back when subjects stop playing Tetris. Similarly, they are interested if the skills learned in Tetris, and the associated brain changes, transfer to other cognitive areas such as working memory, processing speed, or spatial reasoning.

(Photo: Richard J. Haier et al/BMC)

BioMed Central


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Earlier studies of this field have shown that Eastern Asia is the place where the wolf was tamed to become the dog. More detailed information has not been available. Now researchers at KTH have succeeded in further specifying the birthplace of man's best friend.

"For the first time in history it is now possible to provide a detailed picture of the dog including birthplace, point in time and the number of wolves that were tamed," says Peter Savolainen, biology researcher at KTH.

Together with Swedish colleagues and a Chinese research group he has made a number of new discoveries concerning the history of the dog. These discoveries have recently been published in the scientific journal Molecular Biology and Evolution, and establish that the dog arrived 16 000 years ago in Asia, south of the Yangtze River in China. This is considerably earlier as concerns time and place than had previously been established.

"Our previous discoveries from 2002 have not been fully accepted; however with this new data acceptance will probably be greater. The picture is much more detailed," Peter states.

The point in time when the dog emerged is well in line with the point when the population of this part of the world changed from hunting and gathering to farming as a way of life – this was 10 000 to 12 000 years ago.

According to Peter this research indicates that the dog has only one geographical origin, but is descended from a large number of animals. At least several hundred tame wolves, probably even more.

"Considering that it involved so many wolves, this indicates that this event was important and a major part of the culture," he asserts.

He adds that research results have produced several exciting theories such as the fact that the original dog, in contrast to its younger relatives in Europe who were used for herding and as guard dogs, probably ended up in people’s stomachs!

The research result comes from genetical analysis of mitochondrial DNA from 1 500 dogs, from all over the earth.



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The search for the best observatory site in the world has lead to the discovery of what is thought to be the coldest, driest, calmest place on Earth. No human is thought to have ever been there but it is expected to yield images of the heavens three times sharper than any ever taken from the ground.

The joint US-Australian research team combined data from satellites, ground stations and climate models in a study to assess the many factors that affect astronomy – cloud cover, temperature, sky-brightness, water vapour, wind speeds and atmospheric turbulence.

The researchers pinpointed a site, known simply as Ridge A, that is 4,053m high up on the Antarctic Plateau. It is not only particularly remote but extremely cold and dry. The study revealed that Ridge A has an average winter temperature of minus 70ºC and that the water content of the entire atmosphere there is sometimes less than the thickness of a human hair.

It is also extremely calm, which means that there is very little of the atmospheric turbulence elsewhere that makes stars appear to twinkle: "It's so calm that there's almost no wind or weather there at all," says Dr Will Saunders, of the Anglo-Australian Observatory and visiting professor to UNSW, who led the study.

"The astronomical images taken at Ridge A should be at least three times sharper than at the best sites currently used by astronomers," says Dr Saunders. "Because the sky there is so much darker and drier, it means that a modestly-sized telescope there would be as powerful as the largest telescopes anywhere else on earth."

They found that the best place in almost all respects was not the highest point on the Plateau – called Dome A – but 150km away along a flat ridge.

"Ridge A looks to be significantly better than elsewhere on the Antarctic plateau and far superior to the best existing observatories on high mountain tops in Hawaii and Chile," says Dr Saunders.

The finding is published today in the Publications of the Astronomical Society. Located within the Australian Antarctic Territory (81.5◦ S 73.5◦ E), the site is 144km from an international robotic observatory and the proposed new Chinese 'Kunlun' base at Dome A (80.37◦ S 77.53◦ E).

Interest in Antarctica as a site for astronomical and space observatories has accelerated since 2004 when UNSW astronomers published a paper in the journal Nature confirming that a ground-based telescope at Dome C, another Antarctic plateau site, could take images nearly as good as those from the space-based Hubble telescope.

Last year, the Anglo-Australian Observatory completed the first detailed study into the formidable practical problems of building and running the proposed optical/infra-red PILOT telescope project in Antarctica. The 2.5-metre telescope will cost over AUD$10million and is planned for construction at the French/Italian Concordia Station at Dome C by 2012.

"Australia contains no world-class astronomical sites, and Australian astronomers face a choice between being minor players in telescopes in Chile or joining Chinese or European efforts to build the first major Antarctic observatory," says Dr Saunders.

The University of New South Wales




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