Thursday, October 28, 2010


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The European Space Agency (ESA) Rosetta spacecraft recently beamed back to Earth a dramatic set of close-up images as it flew past the asteroid Lutetia, on its way to a comet rendezvous in 2014. But even before Rosetta made its close encounter with the 100-kilometer sized asteroid, astronomers using three of the world’s largest telescopes, including the W. M. Keck Observatory, were busy making their own assessment of the asteroid’s shape and size, as well as searching for its satellites. Their pre-flyby images are being compared this week with those from Rosetta at a meeting of the Division for Planetary Sciences of the American Astronomical Society in Pasadena, California, revealing that the ground-based images are amazingly accurate.

These telescopes all use adaptive optics (AO), which moves the blurring caused by the Earth’s atmosphere. Using something like a fun-house mirror in reverse, AO allows clear pictures to be made, from Earth’s surface, of distant astronomical objects that were impossible to see previously. “Adaptive optics has set in motion an astronomical revolution, bringing new worlds into better view, ranging from asteroids that were previously unresolved pinpoints of light, to the discovery of new planets in other solar systems,” said Dr. William Merline of Southwest Research Institute (SwRI) in Boulder, Colorado, lead scientist of the international team that made the observations, funded by NASA and the National Science Foundation. Two of the telescopes are atop Mauna Kea in Hawaii: the W.M. Keck telescope with its 10-meter mirror and the Gemini telescope, equipped with an 8-meter mirror. The 8-meter Very Large Telescope (VLT) of the European Southern Observatory in Chile was also used.

“We carefully evaluated the size and shape of Lutetia, and pinned down the orientation of its spin pole using telescopes on Earth, prior to the flyby,” reported Dr. Jack Drummond, an astronomer at Starfire Optical Range in Albuquerque, New Mexico, where AO was first developed in the early 1990s and can be considered the cradle of adaptive optics. Drummond is an expert in turning AO images into models of asteroids, detailing their shapes and sizes. He is the lead author on the first of two papers predicting the appearance of Lutetia, which are now in press in the journal Astronomy and Astrophysics. Drummond adds, “after the many years developing these techniques at Starfire, it is gratifying to see how well they work when put to this kind of test.”

Rosetta’s Lutetia encounter provided a rare chance to combine the strengths of spacecraft and ground-based approaches to understand the complex shapes and elusive sizes of asteroids. For decades, astronomers watched Lutetia change brightness as it rotates. Before adaptive optics, such “lightcurve” studies were the only way astronomers could infer the shape of a body like Lutetia. “A sphere will have a flat lightcurve, an egg will have a lightcurve that goes up and down smoothly like an ocean swell, but an irregular potato-shape will look like your EKG on a bad day!”, says Dr. Al Conrad of Keck Observatory, where many of the observations were made.

While lightcurves provide approximate shape, they cannot provide fine detail nor absolute scale. “AO has dramatically improved our ability to determine asteroid shapes from the ground by providing both of these missing ingredients,” said team member Dr. Benoit Carry of Paris Observatory, who led the efforts to produce the “shape model”, derived by combining AO images with decades of lightcurve observations taken on smaller telescopes. “We dubbed this new technique KOALA, for Knitted Occultation Adaptive Optics, and Lightcurve Analysis. With it, we can make much improved use of our own data and of previous studies,” adds Carry, who leads the second paper and worked to develop KOALA in collaboration with Dr. Mikko Kaasalainen of Tampere University, Finland. The results were provided to the Rosetta mission teams ahead of the flyby to assist in planning.

Such ground-based imaging can help prepare for spacecraft flybys in other ways as well. “We determined that the spin pole of the asteroid was highly inclined, and almost in its orbital plane, much like that of Uranus,” says Carry. “We predicted that Rosetta would see only the northern hemisphere and that the southern hemisphere would be dark and cold,” he said --- predictions borne out by the flyby data.

“This encounter enables us to verify, validate, and calibrate our method of combining AO data with lightcurve studies,” noted Merline. “Our goal is to apply this technique to many other asteroids to find their sizes and shapes. The validation from these flyby images gives us confidence that we can do so. We can observe about 200 asteroids in this manner now, and that number will increase as larger telescopes are built,” he adds.

“The tremendous power of the Keck telescope, when coupled with AO, is demonstrated superbly in the Lutetia data,” says Conrad. Because asteroids have no active geology, such as volcanoes or tectonics, their shapes result from collision with other, smaller, asteroids. “Details of shape, such as flat facets or apparent concavities, help reveal the history of asteroid collisions,” he adds. The importance of collisions can be seen in the crater-marked surface of the Moon, reminding us that asteroids continue to pose a threat to Earth.

The AO images from large telescopes, used in concert with lightcurves and the spacecraft images, go beyond validation, however. By combining all data, Lutetia’s shape could be accurately determined, allowing astronomers to compute its volume. Moreover, measurements of the gravitational tug from Lutetia on the spacecraft as it flew past the asteroid will yield a very accurate mass. Mass and volume, taken together, will provide the density of Lutetia. Density is the concept of how much something weighs for its size. For example, two wrapped birthday gifts of the same size, one of Styrofoam™ and one of lead, would invoke very different speculations from a recipient. Asteroid compositions could potentially span the full range from ice to rock to iron. Different compositions of an asteroid could be distinguished by different densities. Astronomers use this “birthday present” approach, combined with information from studies of the brightness and color of the surface, to infer the type of rock (or ice or metal) that makes up an asteroid.

Lutetia was first categorized as an M-type asteroid in the 1970s by team member Dr. Clark Chapman, also of SwRI. “Some people think that M-type asteroids must be metallic, but it has always been known that some might be rocky, like the so-called enstatite chondrite meterorites,” says Chapman. “While Lutetia is not metallic, its composition is still a mystery and it may even be unlike anything we have in our meteorite collections. We hope that getting an accurate density will help us answer this question,” he says. The spacecraft data will be combined with past and future ground-based observations, and the secret of Lutetia’s composition may be revealed in the coming months.

In addition to studying its size and shape, the scientists also searched for satellites of Lutetia, but none were found. “We wanted to know if satellites were present because they would at the same time provide new objects for study during the flyby, but would also pose a risk to the spacecraft that could be avoided with prior knowledge,” says Merline.

(Photo: Dr. Benoit Carry (Paris Observatory), Dr. Al Conrad (Keck Observatory), and Dr. William Merline (Southwest Research Institute))

W. M. Keck Observatory


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A team of Rice University and Lockheed Martin scientists has discovered a way to use simple silicon to radically increase the capacity of lithium-ion batteries.

Sibani Lisa Biswal, an assistant professor of chemical and biomolecular engineering, revealed how she, colleague Michael Wong, a professor of chemical and biomolecular engineering and of chemistry, and Steven Sinsabaugh, a Lockheed Martin Fellow, are enhancing the inherent ability of silicon to absorb lithium ions.

Their work was introduced at Rice's Buckyball Discovery Conference, part of a yearlong celebration of the 25th anniversary of the Nobel Prize-winning discovery of the buckminsterfullerene, or carbon 60, molecule. It could become a key component for electric car batteries and large-capacity energy storage, they said.

"The anode, or negative, side of today's batteries is made of graphite, which works. It's everywhere," Wong said. "But it's maxed out. You can't stuff any more lithium into graphite than we already have."

Silicon has the highest theoretical capacity of any material for storing lithium, but there's a serious drawback to its use. "It can sop up a lot of lithium, about 10 times more than carbon, which seems fantastic," Wong said. "But after a couple of cycles of swelling and shrinking, it's going to crack."

Other labs have tried to solve the problem with carpets of silicon nanowires that absorb lithium like a mop soaks up water, but the Rice team took a different tack.

With Mahduri Thakur, a post-doctoral researcher in Rice's Chemical and Biomolecular Engineering Department, and Mark Isaacson of Lockheed Martin, Biswal, Wong and Sinsabaugh found that putting micron-sized pores into the surface of a silicon wafer gives the material sufficient room to expand. While common lithium-ion batteries hold about 300 milliamp hours per gram of carbon-based anode material, they determined the treated silicon could theoretically store more than 10 times that amount.

Sinsabaugh described the breakthrough as one of the first fruits of the Lockheed Martin Advanced Nanotechnology Center of Excellence at Rice (LANCER). He said the project began three years ago when he met Biswal at Rice and compared notes. "She was working on porous silicon, and I knew silicon nanostructures were being looked at for battery anodes. We put two and two together," he said.

Nanopores are simpler to create than silicon nanowires, Biswal said. The pores, a micron wide and from 10 to 50 microns long, form when positive and negative charge is applied to the sides of a silicon wafer, which is then bathed in a hydrofluoric solvent. "The hydrogen and fluoride atoms separate," she said. "The fluorine attacks one side of the silicon, forming the pores. They form vertically because of the positive and negative bias."

The treated silicon, she said, "looks like Swiss cheese."

The straightforward process makes it highly adaptable for manufacturing, she said. "We don't require some of the difficult processing steps they do -- the high vacuums and having to wash the nanotubes. Bulk etching is much simpler to process.

"The other advantage is that we've seen fairly long lifetimes. Our current batteries have 200-250 cycles, much longer than nanowire batteries," said Biswal.

They said putting pores in silicon requires a real balancing act, as the more space is dedicated to the holes, the less material is available to store lithium. And if the silicon expands to the point where the pore walls touch, the material could degrade.
The researchers are confident that cheap, plentiful silicon combined with ease of manufacture could help push their idea into the mainstream.

"We are very excited about the potential of this work," Sinsabaugh said. "This material has the potential to significantly increase the performance of lithium-ion batteries, which are used in a wide range of commercial, military and aerospace applications
Biswal and Wong plan to study the mechanism by which silicon absorbs lithium and how and why it breaks down. "Our goal is to develop a model of the strain that silicon undergoes in cycling lithium," Wong said. "Once we understand that, we'll have a much better idea of how to maximize its potential."

(Photo: Biswal Lab/Rice University)

Rice University


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Oil recovery using carbon dioxide could lead to a North Sea oil bonanza worth £150 billion ($ 240 billion) – but only if the current infrastructure is enhanced now, according to a new study published today by a world-leading energy expert.

A new calculation by Durham University of the net worth of the UK oil field shows that using carbon dioxide (CO2) to enhance the recovery from our existing North Sea oil fields could yield an extra three billion barrels of oil over the next 20 years. Three billion barrels of oil could power, heat and transport the UK for two years with every other form of energy switched off.

Importantly, at a time of rising CO2 emissions, the enhanced oil recovery process is just about carbon neutral with as much carbon being put back in the ground as will be taken out.

The technique could yield an enormous amount of oil revenue at a time of public service cuts and developing the infrastructure would put the UK in the driving seat for developing enhanced recovery off-shore oil production around the world. It would also allow the UK to develop its carbon storage techniques in line with the UK government's commitments on emissions reductions.

The study, funded by DONG Energy (UK) Ltd. and Ikon Science Ltd., was presented, October 14th 2010, at a conference on Carbon Capture and Storage (CCS), at the Institution of Mechanical Engineers, London. The new figures are conservative estimates and extend a previous calculation that predicted a 2.7 billion barrel yield from selected fields in the North Sea.

The UK Government's Energy Statement, published in April 2010, outlines the continued role that fossil fuels will have to play in the UK energy mix. CO2 enhanced oil recovery in the UK would secure supplies for the next 20 years.

Jon Gluyas, a Professor in CCS & Geo-Energy, Department of Earth Sciences, Durham University, who has calculated the new figures, said: "Time is running out to make best use of our precious remaining oil reserves because we're losing vital infrastructure as the oil fields decline and are abandoned. Once the infrastructure is removed, we will never go back and the opportunity will be wasted.

"We need to act now to develop the capture and transportation infrastructure to take the CO2 to where it is needed. This would be a world-leading industry using new technology to deliver carbon dioxide to the North Sea oil fields. We must begin to do this as soon as possible before it becomes too expensive to do so.

"My figures are at the low end of expectations but they show that developing this technology could lead to a huge rejuvenation of the North Sea. The industrial CO2 output from Aberdeen to Hull is all you need to deliver this enhanced oil recovery."

Carbon dioxide is emitted into the atmosphere when fossil fuels are burnt and the UK Government plans to collect it from power stations in the UK. Capturing and storing carbon dioxide is seen as a way to prevent global warming and ocean acidification. Old oil and gas fields, such as those in the North Sea, are considered to be likely stores.

Enhanced oil recovery using carbon dioxide (CO2 EOR) adds further value to the potential merits of CCS.

Oil is usually recovered by flushing oil wells through with water at pressure. Since the 1970s oil fields in West Texas, USA, have been successfully exploited using carbon dioxide. CO2 is pumped as a fluid into oil fields at elevated pressure and helps sweep the oil to the production wells by contacting parts of the reservoirs not accessed by water injection; the result is much greater oil production.

Experience from the USA shows that an extra four to twelve per cent of the oil in place can be extracted using CO2-EOR. Professor Gluyas calculated the total oil in place in the UK fields and the potential UK gain in barrels and revenue from existing reserves using the American model.

David Hanstock, a founding director of Progressive Energy and director of COOTS Ltd, which is developing an offshore CO2 transport and storage infrastructure in the North Sea, said: "The UK has significant storage capacity potential for captured carbon dioxide in North sea oil and gas fields.

"There is a unique opportunity to develop a new offshore industry using our considerable experience in offshore engineering. This would give us a technical lead on injecting and monitoring CO2 that we could then export to the wider world to establish the UK as a world leader in carbon capture and storage technology."

Professor Gluyas added: "Enhanced recovery of oil in the North Sea oil fields can secure our energy supplies for the next fifty years. The extra 3 billion barrels of oil that could be produced by enhanced CO2 recovery would make us self sufficient and would add around £60bn in revenue to the Treasury.

"Priming the system now would mean we have 10-15 years to develop CO2 recycling and sufficient time to help us bridge to a future serviced by renewable energy."

(Photo: Durnham U.)

Durham University


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Scientists from the MARUM Center for Marine Environmental Sciences and the Max Planck Institute for Marine Microbiology in Bremen on board the German research vessel Meteor have discovered a new hydrothermal vent 500 kilometres south-west of the Azores.

The vent with chimneys as high as one meter and fluids with temperatures up to 300 degrees Celsius was found at one thousand metres water depth in the middle of the Atlantic Ocean. The discovery of the new deep-sea vent is remarkable because the area in which it was found has been intensively studied during previous research cruises. The MARUM and Max Planck researchers describe their discovery in their video blog.

The Bremen scientists were able to find the hydrothermal vent by using the new, latest-generation multibeam echosounder on board the research vessel Meteor that allows the imaging of the water column above the ocean floor with previously unattained precision. The scientists saw a plume of gas bubbles in the water column at a site about 5 kilometers away from the known large vent field Menez Gwen that they were working on. A dive with the remote-controlled submarine MARUM-QUEST revealed the new hydrothermal site with smokers and animals typically found at vents on the Mid-Atlantic Ridge.

Since the discovery of the new vent, the scientists have been intensively searching the water column with the multibeam echosounder. To their astonishment, they have already found at least five other sites with gas plumes. Some even lie outside the volcanically active spreading zone in areas where hydrothermal activity was previously not assumed to occur.

"Our results indicate that many more of these small active sites exist along the Mid-Atlantic Ridge than previously assumed," said Dr. Nicole Dubilier, the chief scientist of the expedition. "This could change our understanding of the contribution of hydrothermal activity to the thermal budget of the oceans. Our discovery is also exciting because it could provide the answer to a long standing mystery: We do not know how animals travel between the large hydrothermal vents, which are often separated by hundreds to thousands of kilometres from each other. They may be using these smaller sites as stepping stones for their dispersal."

Research on deep-sea hydrothermal vents in the Atlantic is the objective of the 30 marine scientists from Hamburg, Bremen, Kiel, Portugal, and France who have been on board the German research vessel Meteor since September 6th. The expedition to the submarine volcano Menez Gwen near the Azores is financed by MARUM, the Center for Marine Environmental Sciences in Bremen. "One of the questions that the team would like to answer is why the hydrothermal sources in this area emit so much methane - a very potent greenhouse gas," says chief scientist Nicole Dubilier, who is also a member of the Steering Committee of the Census of Marine Life Vents and Seeps project ChEss (Chemosynthetic Ecosystem Science). "Another important focus of the research is the deep-sea mussels that live at the hydrothermal vents and host symbiotic bacteria in their gills. The mussels obtain their nutrition from these bacteria."

(Photo: MARUM)

Max Planck Institute


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How can watching primitive fish rot away reveal answers to the fundamental questions of how, when and why our earliest vertebrate ancestors evolved?

An innovative experiment at the University of Leicester that involved studying rotting fish has helped to create a clearer picture of what our early ancestors would have looked like.

The scientists wanted to examine the decaying process in order to understand the decomposition of soft-body parts in fish. This in turn will help them reconstruct an image of creatures that existed 500 million years ago.

Their findings have been published in the journal Proceedings of the Royal Society B. The work was funded by the Natural Environment Research Council (NERC).

The researchers, from the Department of Geology at the University of Leicester, studied the way primitive fish, such as hagfishes and lampreys, decompose to gain an impression of our early ancestry.

The team at Leicester (Rob Sansom, Sarah Gabbott and Mark Purnell) explain: “Our earliest fish-like relatives left fossil remains which have the potential to show us how the group to which we belong evolved from worm-like relatives. But there is a major problem – people are familiar with bones, and teeth as fossils but do not perhaps realise that before these inventions our ancestors consisted of entirely soft bodied creatures. Eyes, organs, guts and muscles all decompose very quickly after death, and as any forensic scientist knows recognising rotted anatomy is difficult.

“Fossils from 500 million years ago provide our only direct evidence of how our earliest vertebrate ancestors evolved from the simple worm-like animals”.

The fossils from the early phase of vertebrate evolution are very rare because being completely soft-bodied they normally rotted away completely after death leaving nothing behind. But very occasionally their remains became preserved as fossils giving us a tantalising glimpse of our early vertebrate relatives.

However, as Rob Sansom explains correctly reading and reconstructing what our ancestors looked like from these semi-rotted remains is tricky. “Interpreting half-a-billion year old fossils is challenging enough in itself, but even more so when the remains comprise only the decayed soft parts which may look quite different to how they would have done in life”.

Sarah Gabbott, one of the leaders of the study, admits that at first it may be difficult to see why spending hundreds of hours studying the stinking carcasses of rotting fish helps us to unlock our evolutionary history, but she points out that the results have been critical to correctly reading fossils from this phase in our history. “In a way our experiments are similar to those going on at the infamous ‘body farms’ in the USA, where human cadavers are left to decompose so that forensic scientists can determine time and cause of death. But, as palaeontologists we want to uncover what an animal which lived 500 million years ago looked like before it died”.

“Our macabre experiments are grisly and smelly but they have revealed, for the first time, what characteristic vertebrate features look like when they are partially decomposed”.

Rare fossilized fish-like fossils are recognised as being part of our evolutionary history because they possess characteristic anatomical features, such as a tail, eyes and the precursor of a backbone. Mark Purnell, explains further: “our experiments have provided us with a set of photofit-like images allowing us to decipher and correctly identify features in fossils. Our ability to flesh out what our earliest vertebrate ancestors looked like and correctly place them on the Tree of Life is critical to understanding whether our earliest relatives evolved in a burst of complexity or gradually over millions of years”

The results published in The Proceedings of the Royal Society B, show that some of the characteristic anatomical features of early vertebrate fossils have been badly affected by decomposition, and in some cases may have rotted away completely. Knowing how decomposition affected the fossils means our reconstructions of our earliest ancestors will be more scientifically accurate.

(Photo: U. Leicester)

University of Leicester


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Some tiny crustaceans living in clear-water alpine ponds high in Washington state's Olympic Mountains have learned how to cope with the sun's damaging ultraviolet rays without sunblock -- and with very little natural pigmentation to protect them.

In fact, in laboratory tests these water fleas, about the size of fruit flies, withstood UV rays much better than the same species of flea taken from a pond less than a mile away, where the water was murkier and thus offered protection.

"The ponds pretty much look the same to us, but the environments are very different for the animals that live there," said Brooks Miner, a University of Washington doctoral student in biology, whose findings are published Oct. 13 in the online edition of the United Kingdom's Proceedings of the Royal Society B. Coauthor is Benjamin Kerr, a UW assistant professor of biology and Miner's doctoral adviser.

"Through their behavior, the Daphnia in the darker ponds can choose a deeper environment where there is no ultraviolet radiation, but the animals in the clear ponds don't have that choice," he said.

Miner conducted field sampling of water and zooplankton from several ponds at 4,200 to 4,800 feet of elevation in the Seven Lakes Basin of Olympic National Park. The samples were gathered from July through September in 2006 through 2009, after winter snow had melted and the water was beginning to warm enough for zooplankton such as the species Daphnia melanica to survive.

Daphnia from ponds below the tree line were protected from the sun because the water was made darker when surrounding vegetation fell into the water, starting a process similar to what happens in a steeping cup of tea. Water in ponds above the tree line was nearly crystal clear, Miner said, so the fleas there did not receive the same protection from the surrounding water. When the fleas were subjected to UV light in the laboratory, those from the clear ponds survived the best.

The biggest surprise, Miner said, was that the water fleas had very little melanin, a protective pigment found in most animals. He noted that fleas from other habitats that have melanin grow at a slower rate than those without it, so the water fleas in the Olympic Mountains apparently evolved less-costly means to deal with UV radiation.

"It could be that they evolved to use other strategies because the ultraviolet isn't as intense here," he said.

Miner sampled some ponds with very clear water that had no Daphnia at all. That, he suggested, could have resulted because UV radiation in those ponds was too intense.

The next phase of his research, part of his doctoral thesis, will examine whether populations that are exposed to high levels of UV radiation but lack melanin have better-developed systems to repair damage to their DNA.

The work, funded in part by the National Science Foundation, will help in understanding how different populations adapt to UV radiation exposure, Miner said. It also could be instrumental in understanding how to maintain the health of aquatic ecosystems in the face of increasing human population and climate change.

(Photo: Anna Coogan)

University of Washington


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World leaders gathering in Japan at the UN's biodiversity summit must agree to put at least 25 percent of the Earth's land and 15 percent of the oceans under protection by 2020 if they are to be successful in their efforts to solve the current global environmental crisis, a new analysis by Conservation International showed.

Putting a larger area of the planet under protection is crucial to secure important biodiversity and the delivery of vital services from nature to people. Natural habitats – and the species and genetic resources they harbor – support the global economy and billions of people who directly depend on them for immediate needs, like food, income and shelter. Currently, about 13 percent of the world's terrestrial areas and less than 1 percent of the open oceans are protected.

The analysis shows that at least 17 percent of the Earth's land is necessary to protect priority areas for known biodiversity and an additional 6-11 percent is needed to ensure adequate storage of carbon in natural ecosystems. The analysis clarifies that protected areas are not just strict nature reserves, but can also refer to areas managed for multiple uses, such as recreation, sustainable economic activities or for their unique beauty and cultural value.

When world leaders met at the Convention on Biological Diversity (CBD), they discussed a set of 20 targets to slow biodiversity loss over the coming decade – one of them being about the need to put areas under protection. The numbers discussed are around 15-20 percent for land and a yet to be determined percentage for oceans.

"The current targets are clearly inadequate in protecting biodiversity and ensuring key services to people. Science shows us that we need more places to be protected and where the key places are," said Conservation International's Frank Larsen, lead author of the analysis. "There is also evidence that the costs of expanding protected areas are compensated by the many benefits, including new jobs and people's ability to withstand the effects of climate change."

Lina Barrera, Conservation International's Director of Biodiversity and Ecosystem Services Policy, added: "The problem is that most of the costs are local, while most of the benefits are global, so politicians do not see much incentive to make things happen. This is the time to be brave and get real about the need to put us on the path for a more sustainable future."

According to the analysis, protecting 25 percent of the lands and 15 percent of the oceans is still a preliminary and conservative estimate. It takes into account the needs to address only carbon storage, but when other important ecosystem services – like water supply, crop pollination and fisheries – are added, the numbers will be higher. Also, in regions highly impacted by environmental degradation, protected areas are likely to be the only intact natural environments that will remain.

(Photo: Conservation I.)

Conservation International


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Does thinking about time or money make you happier? A new study published in Psychological Science, a journal of the Association for Psychological Science, finds that people who are made to think about time plan to spend more of their time with the people in their lives while people who think about money fill their schedules with work, work, and—you guessed it—more work.

To find out how thinking about time or money makes people feel, Cassie Mogilner of the University of Pennsylvania designed an experiment, carried out online with adults from all over the United States, in which they concentrated on money or time. In this experiment, volunteers were asked to unscramble a series of sentences. Some participants were presented with sentences containing words related to time (e.g., “clock” and “day”), whereas others’ sentences contained words related to money (e.g., “wealth” and “dollar”). Next all participants were asked how they planned to spend their next 24 hours. The ones who had been primed to think about time planned to spend more time socializing. People who’d been primed to think about money planned to spend more time working.

She also carried out the experiment on low-income people and found that having them think about time had the same effect, but having them think about money did not. This may mean that low-income people already live concerned about and, therefore, highly focused on money, Mogilner speculates.

But Mogilner wanted to test the effect in the real world, seeing how people actually spent their time. So her research team approached people going into a café on campus to ask them to take part in a questionnaire, which included the word-scrambling task that primed them with thoughts of time or money. These individuals were then watched to see how they spent their time in the café—whether they chatted with people there or on a cell phone, or whether they worked. When they left the café, they filled out a second questionnaire about how happy and satisfied they felt. The results were similar: People who were primed to think about time spent more time socializing and were happier, while people who were primed with money spent more time with their noses buried in books and were less happy when they emerged.

Although focusing on money motivates people to work more, passing the hours working does not generally make one happy. Spending time with loved ones does, and thinking about time might motivate people to pursue these social connections. “There is so much discussion and focus on money, optimal ways to spend and save it, and the relationship between money and happiness,” says Mogilner. “We’re often ignoring the ultimately more important resource, which is time.” She does not suggest that people stop working altogether, but she does say that people need to be reminded to make time for friends and family.

Association for Psychological Science


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Humans are overloading ecosystems with nitrogen through the burning of fossil fuels and an increase in nitrogen-producing industrial and agricultural activities, according to a new study. While nitrogen is an element that is essential to life, it is an environmental scourge at high levels.

According to the study, excess nitrogen that is contributed by human activities pollutes fresh waters and coastal zones, and may contribute to climate change. Nevertheless, such ecological damage could be reduced by the adoption of time-honored sustainable practices.

Appearing in the October 8, 2010 edition of Science and conducted by an international team of researchers, the study was partially funded by the National Science Foundation.

The nitrogen cycle--which has existed for billions of years--transforms non-biologically useful forms of nitrogen found in the atmosphere into various biologically useful forms of nitrogen that are needed by living things to create proteins, DNA and RNA, and by plants to grow and photosynthesize. The transformation of non-biologically useful forms of nitrogen to useful forms of nitrogen is known as nitrogen fixation.

Mostly mediated by bacteria that live in legume plant roots and soils, nitrogen fixation and other components of the nitrogen cycle weave and wind through the atmosphere, plants, subsurface plant roots, and soils; the nitrogen cycle involves many natural feedback relationships between plants and microorganisms.

According to the Science paper, since pre-biotic times, the nitrogen cycle has gone through several major phases. The cycle was initially controlled by slow volcanic processes and lightning and then by anaerobic organisms as biological activity started. By about 2.5 billion years ago, as molecular oxygen appeared on Earth, a linked suite of microbial processes evolved to form the modern nitrogen cycle.

But the start of the 20th century, human contributions to the nitrogen cycle began skyrocketing. "In fact, no phenomenon has probably impacted the nitrogen cycle more than human inputs of nitrogen into the cycle in the last 2.5 billion years," says Paul Falkowski of Rutgers University, a member of the research team.

"Altogether, human activities currently contribute twice as much terrestrial nitrogen fixation as natural sources, and provide around 45 percent of the total biological useful nitrogen produced annually on Earth," says Falkowski. Much of the human contributions of nitrogen into ecosystems come from an 800 percent increase in the use of nitrogen fertilizers from 1960 to 2000.

Another problem: Much of nitrogen fertilizer that is used worldwide is applied inefficiently. As a result, about 60 percent of the nitrogen contained in applied fertilizer is never incorporated into plants and so is free to wash out of root zones, and then pollute rivers, lakes, aquifers and coastal areas through eutrophication. (Eutrophication is a process caused by excess nutrients that depletes oxygen in water bodies and ultimately leads to the death of animal life.)

In addition, some reactions involving nitrogen release nitrogen oxide into the atmosphere. Nitrogen oxide is a greenhouse gas that has 300 times (per molecule) the warming potential of carbon dioxide. In addition, nitrogen oxide destroys stratospheric ozone, which protects the earth from harmful ultraviolet (UV-B) radiation.

"Natural feedbacks driven by microorganisms will likely produce a new steady-state over time scales of many decades," says Falkowski. "Through this steady state, excess nitrogen added from human sources will be removed at rates equivalent to rates of addition, without accumulating."

But meanwhile, the Earth's population is approaching 7 billion people, and so ongoing pressures for food production are continuing to increase. "There is no way to feed people without fixing huge amounts of nitrogen from the atmosphere, and that nitrogen is presently applied to crop plants very ineffectively." says Falkowski.

So unless promising interventions are taken, the damage done by humans to the Earth's nitrogen cycle will persist for decades or centuries. These promising interventions, which would be designed to reduce the need to use fertilizers that add nitrogen to ecological systems, could include:

* Using systematic crop rotations that would supply nitrogen that would otherwise be provided by fertilizers;
* Optimizing the timing and amounts of fertilizer applications, adopting selected breeding techniques or developing genetically engineered varieties of plants that would increase the efficiency of nitrogen use;
* Using traditional breeding techniques to boost the ability of economically important varieties of wheat, barley and rye to interact favorably with the microbial communities associated with plant root systems and do so in ways that enhance the efficiency of nitrogen use.

"While the processes of eutrophication have been recognized for many years, only recently have scientists been able to begin placing the anthropogenic processes in the context of an understanding of the broader biogeochemical cycles of the planet," says Robert Burnap, an NSF program director. This is an important article because it concisely develops this understanding and also provides reasonable predictions regarding the economic and policy dimensions of the problem."

National Science Foundation




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