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- Climate of fear
- Nature 464(7286):141 (2010)
The integrity of climate research has taken a very public battering in recent months. Scientists must now emphasize the science, while acknowledging that they are in a street fight. - Scientific glasnost
- Nature 464(7286):141 (2010)
Russia's scientific reputation will continue to dwindle unless it embraces international research. - Europe's research future
- Nature 464(7286):142 (2010)
The region's member states must follow through on their political and scientific commitments. - Palaeontology: The long and the short
- Nature 464(7286):144 (2010)
- Metabolism: Warm milk
- Nature 464(7286):144 (2010)
- Chemistry: Cellulose busters
- Nature 464(7286):144 (2010)
- Neuroscience: Nerve cell talk
- Nature 464(7286):144 (2010)
- Biomaterials: Squishy particles
- Nature 464(7286):144 (2010)
- Cancer biology: Arsenic activation
- Nature 464(7286):144 (2010)
- Physics: Photon storage for telecoms
- Nature 464(7286):145 (2010)
- Cancer genomics: Melanoma's mutations
- Nature 464(7286):145 (2010)
- Nanotechnology: Harvesting heat
- Nature 464(7286):145 (2010)
- Evolution: Creating cooperation
- Nature 464(7286):145 (2010)
- Journal club
- Nature 464(7286):145 (2010)
- News briefing: 11 March 2010
- Nature 464(7286):146 (2010)
The week in science. This article is best viewed as a PDF. Policy|Business|Market watch|Events|Research|The week ahead|Number crunch|Sound bites In a new decadal economic agenda, the European Union (EU) has said it hopes to raise spending on research and development (R&D) to 3% of the region's gross domestic product by 2020. That measure was supposed to have been hit this year, but spending never rose above 2%. The Europe 2020 strategy, released on 3 March, suggests streamlining bureaucracy to boost private R&D spending, a single EU-wide patent system and completion of the European Research Area, which would enable the free movement of researchers and funding across national borders. Europe also needs to refocus its research agenda onto societal challenges such as climate change, the plan says. See Editorial, page 142. More than 85 million children under the age of five will be immunized against polio in 19 countries across Africa. The effort, part of the Global Polio Eradication Initiative, was announced by the World Health Organization on 4 March. It is an attempt to stop an ongoing epidemic of the disease. The initiative tried to prevent polio spreading in 2009, but not enough children received vaccines. In a 7 March referendum, Switzerland's voters rejected a proposal for animals to be represented by state-funded lawyers in court proceedings involving animal rights. The Zurich canton already provides lawyers for animals in cases of alleged animal cruelty, but campaigners hoped to extend the provision across the country, which already has some of the world's toughest animal-rights laws. The referendum did pass a separate proposal to amend the constitution in order to preserve human dignity in biomedical research; more detailed legislation is expected to follow on stem-cell research and gene therapy. Canada's 2010–11 federal budget features modest increases for major science funding agencies, but also includes plans to review all federal support of research and development. See page 153 for more. A structural shake-up may aid Britain's troubled Science and Technology Facilities Council, which distributes most of the country's physics and astronomy grants but has suffered huge budget holes since it was created in 2007. See page 155 for more. The US Food and Drug Administration (FDA) has been lax in overseeing its Office of Criminal Investigations (OCI), a report from the Government Accountability Office concluded last week. The budget for the OCI, which investigates crimes such as the sale of counterfeit drugs, increased by 73% (after adjustment for inflation) to $41 million in the decade that ended in 2008. But the 230-plus-person office runs with little accountability to senior agency managers, the report says. The FDA largely agreed with the findings. Its commissioner, Margaret Hamburg, says it is taking action. AstraZeneca has announced details of how it plans to reshape its research and development programme. The London-based pharmaceutical company will slash several early-stage projects in topics ranging from neuroscience (schizophrenia, depression, bipolar disorder and anxiety) to infectious disease (hepatitis C and most vaccine projects). Research sites in Lund, Sweden, and in Charnwood and Cambridge, UK, will close. The company is holding to its earlier estimate of a net reduction of 1,800 people affiliated with research and development. Germany's government is to reduce state incentives for solar power from 1 July. Solar feed-in tariffs — the price an electricity utility must pay to generators of solar energy — have been dropping by 8–10% a year since they were introduced in 2000; now they will be cut by a further 16% for roof-top panels and abandoned for panels installed in converted farmland. Those installing and generating solar power will see lower returns — meaning that solar panel manufacturers will have to drop their prices. But as last year's plummeting price for solar modules has not yet been fully passed on to installers, Germany should end up installing about the same solar capacity as in 2009, according to analysts Bloomberg New Energy Finance in London. A closely watched Alzheimer's treatment has failed to show an effect on the disease in two late-stage clinical trials, the pharmaceutical company Pfizer, based in New York, announced on 3 March. Latrepirdine (dimebon) — already used as an antihistamine in Russia — had seemed promising enough for Pfizer to enter into a $225-million deal in 2008 with the drug's developer, Medivation, a biopharmaceutical company in San Francisco, California. But in a trial involving 598 patients it performed no better than placebo. Medivation's share price plunged after the announcement. SOURCE: PNAS More than one-fifth of the carbon dioxide produced by China in 2004 was emitted to provide goods and services for non-Chinese consumers, mainly in western Europe, the United States and Japan (see chart). The statistic comes from the latest study to look at an alternative style of carbon accounting — one that assigns CO2 emissions to the consumers responsible for them. By contrast, inventories such as those reported under the United Nations Framework Convention on Climate Change (UNFCCC) simply tally the amount of gas each country produces. Ken Caldeira and Steve Davis, at the Carnegie Institution for Science's lab in Stanford, California, published their findings this week (S. J. Davis and K. Caldeira Proc. Natl Acad. Sci USA doi:10.1073/pnas.0906974107; 2010). The most comprehensive of its kind, the analysis takes trade figures from 113 countries across 57 industry sectors and finds that 23% of global CO2 emissions (or 6.2 billion tonnes of CO2) was traded internationally in 2004. In some wealthy countries, including Britain and France, more than 30% of consumption-based emissions are imported; in the United States, the figure is 11%. Caldeira thinks that the UNFCCC's production-based inventories should be supplemented with figures that track where the carbon is ultimately being consumed. ESO/S.BRUNIER The €800-million (US$1.1-billion) European Extremely Large Telescope will probably be built at Cerro Armazones, in Chile's Atacama Desert. The European Southern Observatory (ESO) announced on 4 March that its advisory committee had recommended the site (pictured) above Spain's La Palma and three other Chilean competitors. The Atacama Desert has the best overall sky quality and would allow the 42-metre-diameter telescope to operate in sync with ESO's existing Paranal Observatory, the committee said. A final decision will be made no later than June. US ARMY/AP A US National Research Council report published on 4 March pronounced "a high degree of confidence" in protection of workers and the public at biocontainment laboratories in Fort Detrick, Maryland, despite finding numerous deficiencies in the way environmental hazards at the site were modelled. The lab (where anthrax researcher David Norwood is pictured) was the source of the anthrax spores that killed five people in 2001. The US Army Medical Research Institute of Infectious Diseases is expanding its facilities there under a congressional mandate, but citizens living nearby had complained of risks including an inadequate environmental impact statement. The council's report concluded that it "would not be useful" to redo the analysis because construction has already begun on the project. China plans to launch an unmanned orbiting space module in 2011, the first component of a proposed permanent space station. Tiangong-1, or 'Heavenly Palace', will first be used for orbital docking practice with three spacecraft; after that, crewed ships will visit the module. Aerospace official Qi Faren told state media on 3 March that "technical reasons" had pushed back an original launch target of late 2010. The US Department of Energy last week announced $100 million for a third round of research programmes at its fledgling Advanced Research Projects Agency-Energy (ARPA-E). The agency is geared towards energy research that might not be funded through traditional science grants. Research proposals are requested in energy storage, electrical power delivery and energy-efficient cooling technology. The announcement came at the inaugural ARPA-E summit. Conservation deals, including a ban on international trade in bluefin tuna and greater protection for the African elephant, are on the table at a meeting of the Convention on International Trade in Endangered Species in Doha, Qatar. → www.cites.org The American Physical Society hosts its spring meeting in Portland, Oregon. → go.nature.com/Y8YXiL Miami, Florida, hosts a 'State of the Arctic' conference, which will discuss current understanding of the rapidly changing Arctic — and what can be done about it. → http://soa.arcus.org The liability that experts polled by financial analysts at Swiss bank UBS think GlaxoSmithKline faces as a result of lawsuits filed over its diabetes drug Avandia. Source: The Guardian Connie Hedegaard, European commissioner for climate change, is pessimistic over whether the world will draw up a new treaty on climate change in 2010. Source: Financial Times There are currently no comments. This is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements. - Outcry over scientists' dismissal
- Nature 464(7286):148 (2010)
Following years of acrimony, two high-profile researchers in Mexico have been expelled from their institute. To the scores of scientific luminaries who support them, the Terrones brothers are two of the brightest stars of Mexican science and have raised the nation's profile in nanotechnology. Yet the federal Institute for Scientific and Technological Research of San Luis Potosí (IPICYT) fired Humberto and Mauricio Terrones Maldonado in December, and their future in their home country is now looking dim. Mauricio Terrones is an established nanotech researcher.R. ROMERO/NEWSCOM International science leaders say that the case serves as an example of how entrenched scientific bureaucracies in developing nations can drive away promising researchers, especially those who have been trained abroad. "This is a major loss for Mexican science," says Mildred Dresselhaus, a nanotechnology researcher at the Massachusetts Institute of Technology (MIT) in Cambridge and a former president of the American Association for the Advancement of Science, who has advocated on behalf of the Terrones. David Ríos Jara, IPICYT's director, rejects these arguments. "The foreign scientists' perception that Mexican science is in imminent peril is a flat misconception," he says, adding that "there are about 20,000 researchers in the country carrying out high-quality research in many areas". Ríos says that he was forced to terminate the employment of the brothers because they had violated institute rules and Mexican laws. Scientists outside Mexico have heard only one side of the story, he says. After receiving their doctorates in the United Kingdom and doing postdoctoral work abroad, the Terrones returned to Mexico and established the country's first nanotech lab, located at IPICYT, about a decade ago. They secured several large grants, collaborated with top researchers abroad and published well-cited papers on carbon nanotubes and buckyballs in high-impact journals. But several years ago, disagreements arose between the Terrones and the administration at IPICYT over the operation of their lab (see Nature 454, 143; 2008). Tensions between the two sides came to a head late last year, and the brothers were expelled from their lab in December. "I won't work in a developing nation again," says Mauricio. "Other Mexican universities are afraid to hire us," adds Humberto. Centre of attention In an e-mail to Nature on 25 February, Ríos accuses the brothers of several "irregularities": failing to include IPICYT in four technology patent applications, not securing proper authority to travel extensively last year and improperly working for a private university. The Terrones deny any impropriety and blame professional jealousy for their firing, a charge that Ríos rejects. In 2008, the Terrones brothers' situation attracted the attention of prominent scientists, including British researcher Harold Kroto and Mexico's Mario Molina, both winners of the Nobel Prize in Chemistry. They unsuccessfully lobbied for a compromise with Mexican President Felipe Calderón Hinojosa and other top officials. Kroto and some 70 other scientists are again petitioning in support of the brothers (see Correspondence from H. W. Kroto et al., page 160). The appeals by researchers outside Mexico have not calmed the situation. In a written response to enquiries from Nature, Rosaura Ruiz Gutiérrez, president of the Mexican National Academy of Science, said that the letter sent to President Calderón in 2008 "created a great deal of unease in the Mexican scientific community, since its arguments lack sufficient knowledge of the regulations in Mexican institutions". Ruiz said the case has divided the Mexican scientific community and that "proper channels exist for resolving this disagreement". Some are pessimistic about the chances for resolving the dispute. Ljubisa Radovic is a Spanish-speaking materials scientist at Pennsylvania State University in University Park who visited San Luis Potosí in an unsuccessful attempt to broker a compromise. He blames the impasse on the IPICYT administration. "If you have stars like the Terrones," he says, "you take care of them." Dresselhaus got a personal view of the escalating conflict in mid-December, when she visited IPICYT to participate in the doctoral defence of Jessica Campos-Delgado, one of the Terrones' students. An unusual number of uniformed guards were present, apparently to head off a disturbance by students supporting the Terrones, according to the brothers and Campos. The Terrones were intermittently called away for discussions with their lawyers and administrators. Around that time, their e-mail accounts were shut down, and by the end of December, their pay cheques stopped coming. "The whole event was bizarre," says Dresselhaus. Kroto, who oversaw Mauricio's doctorate at the University of Sussex in Brighton, UK, says that he worries about the Terrones' remaining students. In an e-mail addressed to the "International Community" in late January, several students and staff in the Terrones' nanotech group said "we remain extremely worried that we might be fired on a whim" and that they had been pressured to retract their criticisms of the administration. Ríos says that the IPICYT administration has offered its full support to the remaining students. The current students declined interview requests from Nature. Campos, who received her degree, says that she remains shaken by the Terrones' firing. She will soon leave Mexico and head for a postdoctoral fellowship in Brazil. "I don't know if I can or will return, if I have to deal with the people who did this," she says. That will be a loss for Mexico. During her doctoral training, Campos spent six months in Dresselhaus's lab at MIT, providing a key contribution to a method to enhance graphene nanoribbons for mass production as semiconductors (X. Jia et al. Science 323, 1701–1705; 2009). MIT, in conjunction with IPICYT, applied for a US patent application on the technology, and MIT now is seeking licensing agreements. Helpful discussions Two of the patents that Ríos says the Terrones failed to disclose involve Mexico's largest juice producer, Grupo Jumex in Tulpetlac. The other two are owned by institutions in Japan: the National Institute for Materials Science (NIMS) in Tsukuba and Shinshu University in Wakasato. The science for the patents was "partly or fully developed" at IPICYT, Ríos wrote, and "it goes without saying how serious stealing intellectual property is". Gerd Reiband, a head engineer at Jumex, says that the company filed the two patent applications on its own because the work was conducted there, not at IPICYT. There was no agreement to financially reward the Terrones and their names were included as a courtesy for their helpful discussions. Scientists at the two Japanese institutions say similar conditions applied to their patents. Ajayan Vinu, a materials scientist at NIMS, worked with Mauricio when the Mexican scientist was on a fellowship in Japan. Vinu says that he was astounded to hear that advice that Mauricio had offered had played a part in his dismissal. ADVERTISEMENT "Tell them they are crazy," says Vinu, who was not contacted for details by IPICYT officials. "This is dangerous for science." The brothers remain in San Luis Potosí and are considering legal action to fight the termination of their employment. There are currently no comments. This is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements. - Climate e-mail rerun
- Nature 464(7286):149 (2010)
Arriving at work on 5 March, Stanford University ecologist Paul Ehrlich found a rambling and highly profane voice message from someone identifying himself as John Q Public. In one of his more lucid moments, the caller labelled Ehrlich and his colleagues in the climate-science community as "progressive communists attempting to destroy America". There are currently no comments. - Old rocks drown dry Moon theory
- Nature 464(7286):150 (2010)
Samples collected during Apollo missions suggest a wet interior, raising questions about lunar origins. Click for larger image Larry Taylor always said he'd eat his shorts if water was ever found on the Moon. He never expected his own research to bring that pledge back to haunt him. The petrologist, based at the University of Tennessee in Knoxville, was just 32 years old at the first Lunar and Planetary Science Conference in 1970, where his colleagues described their analyses of Moon rocks collected the previous year during the Apollo 11 mission. Taylor saw only pure metallic iron in the samples — a sign that there wasn't any water around to rust the iron. This and other results that year led to the party line: the Moon is, and always was, bone dry. Forty years on, at the same annual conference near Houston, Texas, Taylor and his colleagues announced that they have been wrong all along. At the meeting last week, three groups presented evidence that certain crystals in the volcanic rocks collected by Apollo astronauts contain as much as several thousand parts per million of water. These findings go much deeper than the glimpses of frozen water on the Moon's surface — discoveries that were made recently by India's Chandrayaan-1 and NASA's Lunar Reconnaissance Orbiter spacecraft (see Nature doi:10.1038/news.2009.931; 2009). The new studies of the Apollo samples provide hints of what lurks within the Moon. The results suggest that the lunar interior has always held some water — challenging theorists to change their thinking about how the Moon formed during a fiery impact, and how the once-molten body cooled. The work also hints that comets have played a more important part in delivering water to the Moon than researchers had previously thought. "This is revolutionary," says Linda Elkins-Tanton, a lunar scientist at the Massachusetts Institute of Technology in Cambridge. As for Taylor, the one-time water sceptic has eaten his words — and more. In January, colleagues gave him a chocolate cake, iced white with pink polka dots to represent his boxer shorts. "The findings go deeper than the glimpses of frozen water on the Moon's surface; the Apollo samples provide hints of what lurks within the Moon." The first clues to a wet lunar interior were published in 2008, says Taylor, after researchers found traces of water buried inside beads of volcanic glass found in Apollo samples (A. E. Saal et al. Nature 454, 192–195; 2008). It took advances in ion mass spectrometers to detect such tiny amounts of water. It also required people willing to challenge 40 years of conventional wisdom and endure the chuckles of disbelieving colleagues. Although the volcanic beads offered evidence for inner water, those rocks also had limitations. The beads formed in violent, 'fire-fountain' eruptions that significantly altered their chemistry, making them uncertain proxies for rocks inside the Moon. The new detections of water came from a different source — tiny apatite crystals found within dark basalt from the Moon's maria, or 'seas'. The crystals, which took shape within the vast fields of flowing lava that once filled the maria, contain much higher amounts of water than the glass beads. Because the basalt came from quieter eruptions than the dramatic fire fountains that formed the glass, Taylor says, the chemistry of these rocks can more easily be used to calculate the water content of the original magma body from which they came, deep in the Moon's mantle. The three groups at the meeting reached different conclusions about the past water content of the Moon, but all three suggest that the lunar interior could have contained tens of thousands of times more water than previously thought, although still orders of magnitude less than Earth. A Moon with so much moisture would have been a more active place. Water lowers the melting point of mantle rock and makes it easier for magma to form. It even allows for the possibility of convection of rock inside the Moon, something long discounted. This would have helped the Moon to cool more quickly than researchers previously thought, and could explain some puzzling aspects of lunar geology. One of the groups went further and discovered a clue to the origins of the water. James Greenwood of Wesleyan University in Middletown Connecticut, working with Taylor, found that Moon water has a much higher proportion of deuterium, or heavy hydrogen, than does water on Earth. The ratio found for the Moon resembles that of comets. A weighty problem This ratio came as a surprise. The Moon is thought to have formed when a Mars-sized body hit Earth soon after its formation, melting much of the planet and flinging up molten rock that eventually coalesced and hardened to form a satellite. That picture suggests that Earth and the Moon should have started with similar ratios of heavy water. But the markedly heavier mix of water in the lunar samples has forced researchers to consider alternative explanations. One idea, Taylor says, is that a bevy of comets struck the Moon soon after the giant impact responsible for its formation, and that the heavy comet water mixed into the Moon's magma ocean. The comets would have struck Earth too, but because the young planet had a significantly larger supply of water, the heavy water deposited on Earth was greatly diluted. Alternatively, perhaps the heat of the impact evaporated the lighter water from the Moon, leaving it enriched in heavier water. Or maybe the impactor itself contained large amounts of heavy water. According to Elkins-Tanton, "this may all lead to a reconsideration of the giant-impactor theory," especially in how it relates to the origin of lunar water. But not yet. The heavy-water results could reflect nothing more than a specific spot of enrichment — the impact site of an ancient comet, for example. And some researchers aren't convinced that the Moon is a wet as the new results suggest. Chip Shearer at the University of New Mexico in Albuquerque has been analysing chlorine in volcanic rocks, which can provide some information about ancient water because of the way chlorine would have bound to it to form other compounds. He says that the estimated water concentrations reported last week are at the upper limit of the range allowed by his chlorine results. ADVERTISEMENT Sorting out the debate will require new samples. To Clive Neal at the University of Notre Dame in Indiana and chair of a NASA lunar advisory group, that means returning to the Moon. But before then, researchers will be revisiting the rocks collected by Apollo astronauts. At the meeting last week, Taylor drew an index card out of his wallet that contained the five-digit codes for three more samples he was going to retrieve from the vaults at the Johnson Space Center, on the other side of Houston from the conference. He has made the trip many times before. "Being an old fart," he says, "I know the ropes." There are currently no comments. This is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements. - Biology thinks big to stay cuts
- Nature 464(7286):151 (2010)
Biologists with grandiose research proposals often turn to the risk-tolerant Human Frontier Science Program (HFSP) to get themselves started. However, the world's only intercontinental research funding agency is now working hard to convince its members — 13 individual nations plus representation from the European Union — that frontier research is a wise investment in tough economic times. There are currently no comments. - Science survives Canadian budget
- Nature 464(7286):153 (2010)
While many nations are slashing science funding in austerity budgets, Canada's financial plan for the coming year defies the trend, leaving most scientists grudgingly happy with the results. The federal budget for 2010–11, unveiled on 4 March, provides modest increases for the major science funding agencies, after a cut last year (see Nature 457, 646; 2009. - Plant biologists fear for cress project
- Nature 464(7286):154 (2010)
Is enthusiasm withering for funding studies into Arabidopsis thaliana? Click for larger image The brilliant career of a diminutive weed may have hit a snag. Arabidopsis thaliana has been the darling of plant biologists for some 30 years because of its small genome and rapid growth, and in 2000 it became the first plant to have its genome sequenced. To capitalize on this, the US National Science Foundation (NSF) soon afterwards dedicated US$200 million towards determining the function of every Arabidopsis gene by 2010. Now time is nearly up, although the work is far from done. And with the NSF unlikely to extend the project, Arabidopsis researchers fear that the plant's popularity with funders is on the wane. The appeal of Arabidopsis is as a stand-in for unwieldy food crops that grow slowly, take up lots of space and have large genomes. By studying thousands of plants in a single greenhouse, scientists can conduct experiments in a fraction of the time and space required for crop species. But sequencing technology is improving so quickly that genome size is no longer the barrier it once was. As more crop genomes are sequenced, including maize (corn) and rice, researchers can increasingly study crop species directly, rather than relying on a model plant. "There's obviously a drive back to increased funding of crop plant research," says Mark Stitt at the Max Planck Institute of Molecular Plant Physiology in Potsdam, Germany. "This is fair and good, but there is a quite serious risk that some of the advances made in Arabidopsis research in the past ten years may not be sustained." Data from the NSF's 2010 project (see 'Inside Arabidopsis' for a few highlights) have been used to tackle fundamental questions about development, pathogen resistance and hormone signalling. Annotation of the Arabidopsis genome — the linking of biological data to sequence information — is now considered among the highest quality of all sequenced genomes. "People seem to feel, 'Oh," But the project has fallen short of its original goal of determining the function of every gene. Most Arabidopsis genes have been characterized in some fashion, for instance by observing their expression in a high-throughput assay, says Eva Huala, director of the Arabidopsis Information Resource (TAIR), a database at the Carnegie Institution of Washington in Stanford, California. However, Huala estimates that direct experimental data about function are available for only a third of all Arabidopsis genes. Money was one hurdle. Although the project was designed for an annual budget of $100 million, it actually received about a fifth of that sum. Then there were biological obstacles. Arabidopsis has many large gene families whose constituent genes have overlapping functions — a common phenomenon in plants. Knocking out one gene in the family often did not affect the plant, because other genes were able to compensate. "When the programme was designed, there was this idea that if we march through every gene and look at its phenotype with a knockout mutant, that would give us great insight into the functional identity of every gene," says Philip Benfey, a plant biologist at Duke University in Durham, North Carolina. "The reality was much more complicated." Systems approach In 2008, the project team drafted a proposed Arabidopsis 2020 programme that would focus on systems biology, an approach that would use the large data sets generated in the 2010 programme to develop models of plant function. That programme, however, is unlikely to be funded, according to Parag Chitnis, deputy director of the NSF's Division of Molecular and Cellular Biosciences. "Now we are thinking beyond just one model organism," he says. The NSF's Plant Genome Research Program and the Department of Agriculture's competitive funding programme have increasingly favoured grants for work on agricultural species in recent years. The NSF has also begun phasing out funding for TAIR, which is partially funded by 2010 project funds (see Nature 462, 258–259; 2009). "People seem to feel, 'Oh, Arabidopsis is done. Let's just move to the real stuff,'" says Natasha Raikhel at the University of California, Riverside. "Well, it's not done." Raikhel adds that researchers have only just begun to tackle some key biological questions in Arabidopsis, such as how cell walls form. Researchers developing ways to turn cellulose into ethanol need to know how plants build their cell walls, but it is often more difficult to characterize the function of genes in biofuel crops. ADVERTISEMENT And although Benfey welcomes additional funding for crop research, he notes that the extensive data already available for Arabidopsis make it the best species to advance plant systems biology. It would be difficult to build general models of flowering, for example, using data collected from many different plants, he says. Even crop researchers have a good word for the little weed. "It's very important for the entire plant and agricultural community that Arabidopsis research should continue to be funded." says Edward Buckler, a maize geneticist at Cornell University in Ithaca, New York. There are currently no comments. This is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements. - Graphic detail: Securing UK science
- Nature 464(7286):155 (2010)
There are currently no comments. - A rescue plan for UK physics funding
- Nature 464(7286):155 (2010)
Britain's most troubled research council is about to undergo radical surgery. On 4 March, UK science minister Paul Drayson unveiled his plan to reform the Science and Technology Facilities Council (STFC), the main research council that provides funding for particle physics, space science, nuclear physics and astronomy. There are currently no comments. - Nuclear weapons physics: Welcome to the Atomic Weapons Establishment
- Nature 464(7286):156 (2010)
With the launch of a powerful laser facility, Britain's most secretive lab is opening up to academics. Geoff Brumfiel secures a preview. Download a PDF of this story Aldermaston is a picturesque English village with red-brick houses, tidy gardens and an inviting local pub. But just to the south lies a much more forbidding set of buildings. Behind double-fencing and guarded gates is the sprawling campus of the Atomic Weapons Establishment (AWE), Britain's most hush-hush research laboratory. The 304-hectare facility, a converted Second World War airfield, is home to the roughly 4,000 scientists, engineers and technicians who are responsible for maintaining Britain's nuclear warheads. The Ministry of Defence, which oversees the AWE, is notoriously tight-lipped about the lab's activities, and scientists who work there generally try to keep a low profile. But within the next few months, the AWE's most ambitious and expensive scientific project is due to be completed, and it is prompting the lab to open up its doors — at least a chink. The new Orion facility will be home to 12 high-powered laser beams capable of heating and compressing material to millions of degrees Celsius in less than a nanosecond. Housed in a gleaming building the size of a soccer pitch, the laser system will provide physicists at Aldermaston with crucial data about how components of their ageing nuclear weapons behave. Under current plans, around 15% of Orion's time will be offered to academics wanting to study conditions on stars or inside giant planets. And in that open spirit, researchers there invited a Nature reporter in for a look around. In most respects, Orion is the smaller cousin of the US National Ignition Facility (NIF) in Livermore, California, which is already running academic experiments. When operating at full steam, the NIF will use 192 lasers to create around 4 million joules of energy, some 100 times more powerful than Orion. What makes the AWE's laser notable is the exquisite precision that it will give researchers in controlling the heat and compression exerted on the materials placed in its target chamber — and the fact that the AWE is sharing it at all. "The defence ministry is notoriously tight-lipped about the lab's activities." The motivations for collaboration are not entirely selfless. The defence establishment wants to provide scientists inside the security cordon with the sort of intellectual stimulation needed to keep them on their toes; it also has an incentive to nurture the wider community of physicists from which it draws its staff. "We want to demonstrate that we maintain high standards for our science," says Daryl Landeg, the AWE's chief scientist. And academics far beyond Aldermaston are keen to cross the fence. At present, Europe has only a handful of comparable laser facilities, says François Amiranoff, director of the Laboratory for the Use of Intense Lasers at the École Polytechnique near Paris. "A facility like Orion is very, very interesting for the scientific community," he says. Secrecy rules Britain established its atomic-weapons programme at the current AWE site in 1950, after close involvement in the Manhattan Project. The campus, which also houses facilities for manufacturing and storing sensitive nuclear materials, is shielded by the nation's strict secrecy laws, and has historically shunned visitors. Things have started to change over the past decade, says Steven Rose, a physicist at Imperial College London who headed the AWE's plasma-physics division from 2001 to 2004. "The old argument that secrecy was paramount I think perhaps holds less sway these days," he says. "They've realized that you can do some things in collaboration with the outside world." Enter Orion, the £183-million (US$274-million) laser on which construction began in 2005. The machine has ten conventional lasers (see graphic), each of which can deliver 500 joules of energy in about a nanosecond (a billionth of a second). It also has two short-pulse lasers, which deliver the same amount of energy in just half a picosecond (a trillionth of a second). Click for larger image Inside Orion's main building, workers in Teflon suits and hairnets are busily scrambling around gigantic white scaffolding. The structure will soon hold the mirrors, amplifiers and lenses needed to boost and focus the 12 beams onto their target, which lies in a separate chamber behind 1.5 metres of solid concrete, a shield necessary to contain the radiation generated when the laser beams hit. The exceptional cleanliness in the laser halls and target area (and expected of visitors) is about more than aesthetics: a stray hair in the path of the intense beam could cause irregularities and crack an expensive mirror or grating. Orion's main mission, like that of the NIF, is to explore how nuclear weapons work, particularly as they get older. In 1998, Britain ratified the Comprehensive Nuclear-Test-Ban Treaty, an international agreement prohibiting tests of nuclear weapons. Scientists in Britain and worldwide have therefore been busy developing computer models to simulate nuclear warheads and work out whether the weapons will still detonate after decades in storage, and what type of detonation will result. What is missing, however, are actual data. US scientists hope that the more powerful NIF will contribute some of those data, by generating temperatures and pressures so high that they will spark nuclear fusion in small quantities of two hydrogen isotopes, deuterium and tritium. This fusion process would resemble conditions inside the most powerful stage of a modern thermonuclear weapon. If the NIF is a thermonuclear hammer, then Orion is a scalpel. The smaller facility will never achieve full-scale fusion, but it will be able to carefully control conditions inside test materials such as uranium. Pressure and temperature usually go hand-in-hand, explains Peter Roberts, head of the AWE's plasma-physics department. "You pump up a tyre with a bicycle pump and it gets hot," he says. But Orion can get around this. It can compress a material with its long, nanosecond pulses then suddenly heat it with its very short, half-picosecond pulses. The result is 'isochoric heating', an unusual condition in which a material is heated so quickly that it doesn't have time to expand. This capability allows Orion to probe materials at wide-ranging combinations of temperatures and pressures. In particular, researchers will use Orion to explore two key parameters for materials used in nuclear weapons: their opacity and their equation of state. The first describes how radiation travels through a material — in this case, the two stages that make up a weapon. The first stage, or primary, is a few kilograms of plutonium that are compressed by conventional explosives until they begin a runaway nuclear reaction. The radiation from that reaction is then focused onto the 'secondary', the stage in which hydrogen isotopes create a much larger blast using nuclear fusion. Researchers want to know what the opacity is and how it changes with age so that they can model radiation's flow from the primary to the secondary and verify whether the warheads will still work. The other parameter — the equation of state — describes how a material behaves at enormous pressures and temperatures. By generating data on these and other crucial parameters, Orion will give nuclear-weapons! scientists the information they need to ensure that their models are correct. "You can't look this stuff up," Rose says. The researchers running the NIF often emphasize the giant laser's applications in energy production and fundamental science over its military role; it could, for example, lead to new reactors that produce electricity using tiny fusion implosions. Orion's scientists are much less circumspect. "We're working on weapons physics fundamentally," Roberts says. Nevertheless, he and others at the lab are eager to give civilian scientists an opportunity to use the laser — and the academics are eager to try out its capabilities. "It will have significant characteristics that no other laser in the United Kingdom or indeed Europe has," says Mike Dunne, director of the Central Laser Facility at the Rutherford Appleton Laboratory near Didcot, UK. Dunne says that Orion should relieve the strain on the facility's Vulcan laser, Orion's massively oversubscribed civilian counterpart. Extreme conditions Physicists studying astronomical objects find themselves in a situation not dissimilar to that of nuclear-weapons scientists: unable to recreate the extreme conditions inside a star, for example, and largely dependent on complex computer models to show how they work. Orion will not reach stellar temperatures and pressures, but it will be able to create flows of hot ionized gas with the sorts of high magnetic fields and temperatures that mimic parts of stars and other astronomical objects. By scaling up the data from Orion, astrophysicists should be able to improve their models, Dunne says. The laser facility can also inform more abstruse, fundamental work in atomic physics. Current theory does well at describing normal matter and extremely hot matter that has been stripped of electrons. But it cannot describe situations in which atoms are subjected to high levels of radiation without losing all their electrons. By heating a test material, then probing it with its short-pulse beams, Orion can provide data that can extend existing theories into this middle region, says Amiranoff. This warm, dense matter may exist at the heart of gas giants such as Jupiter, or even within Earth's core. Scientific collaborations are not slated to begin on Orion until the second half of 2012, and proposals to use the facility will be submitted through the system being used for Vulcan and other UK lasers, rather than being determined by weapons scientists. This open peer-review of proposals "is absolutely critical to gaining the confidence of the community", Dunne says. "If some committee inside of the wire assessed relative merits, there would always be the suspicion that they were picking topics that helped their programme rather than just because they were good science." ADVERTISEMENT Back on the AWE's campus, the weapons scientists are eagerly preparing for their new guests. Tom Bett, who helps to manage construction, shows off a data-analysis room purpose-built for unclassified visitors and lined with sleek computer terminals. (The weapons work will be done in a separate room, he explains, and the data will be stored on servers locked inside vaults.) On the ground level, floor-to-ceiling windows illuminate a bright reception area — the first thing that visiting researchers will see as they are welcomed to the new laser facility. "Those windows," Bett adds proudly, "are all bullet-proof." There are currently no comments. This is a public forum. Please keep to our Community Guidelines. You can be controversial, but please don't get personal or offensive and do keep it brief. Remember our threads are for feedback and discussion - not for publishing papers, press releases or advertisements. - Bioengineering: What to make with DNA origami
- Nature 464(7286):158 (2010)
DNA is the kind of polymer that chemists dream about. Because its complementary sequences can bind to one another, individual molecules of the right sequence will assemble all by themselves into intricate shapes and structures at the nanoscale. There are currently no comments. - Science and Mexico are the losers in institute politics
- Nature 464(7286):160 (2010)
Events at Mexico's Instituto Potosino de Investigación Científica y Tecnológica (IPICYT) have escalated to crisis point (see page 148). We the undersigned call on the world's academic community to help reverse the damage currently being done in this research institution, once a shining example for all developing nations. - Colour-coded targets would help clarify biodiversity priorities
- Nature 464(7286):160 (2010)
In this International Year of Biodiversity, we should be setting ambitious but realistic targets for biodiversity policy over the next ten years. Those shaped at last month's sixth Trondheim Conference on Biodiversity in Norway will be refined by the Subsidiary Body on Scientific, Technical and Technological Advice in May and at the Conference of the Parties of the Convention on Biological Diversity (CBD) in October. - Barriers to carbon capture and storage may not be obvious
- Nature 464(7286):160 (2010)
There's more to 'Buried trouble' than whether carbon dioxide should be injected under urban areas or offshore (Nature 463, 871–873; 2010). - Accelerating HIV vaccine development
- Nature 464(7286):161 (2010)
Translational-research programmes supported by flexible, long-term, large-scale grants are needed to turn advances in basic science into successful vaccines to halt the AIDS epidemic, says Wayne C. Koff. - Evolution of the motor car
- Nature 464(7286):163 (2010)
A proposed reinvention for urban motoring based on ultra-small electric vehicles does not address the bigger environmental or social challenges, finds Daniel Sperling. - Space to contemplate
- Nature 464(7286):164 (2010)
Amazing discoveries tend to follow a satellite launch or telescope's first light. Physicists have traced galaxies across most of the visible Universe and have seen the top quark. - Genius who shuns the limelight
- Nature 464(7286):165 (2010)
Mathematics rarely makes the news. One exception was the proof of the century-old Poincaré conjecture in 2003. - Q&A: Peter Hessler on urbanization in China
- Nature 464(7286):166 (2010)
In Country Driving, the final book in his China trilogy, Peter Hessler recounts his 11,000-kilometre drive across China to see at first hand the effects of rapid industrialization. The New Yorker journalist explains how mass migration to cities brings out people's resourcefulness, but also how the speed of social and environmental change leads them to seek meaning in their lives. - Structural biology: When four become one
- Nature 464(7286):167 (2010)
Every machine is made of parts. But, as the new structure of the HIV integrase enzyme in complex with viral DNA shows, one could not have predicted from the individual parts just how this machine works. - 50 & 100 years ago
- Nature 464(7286):168 (2010)
Strange World of the Moon. An Enquiry into Lunar Physics. - Atmospheric chemistry: Wider role for airborne chlorine
- Nature 464(7286):168 (2010)
Unexpected chlorine chemistry in the lowest part of the atmosphere can affect the cycling of nitrogen oxides and the production of ozone, and reduce the lifetime of the greenhouse gas methane. - Supramolecular chemistry: Sticking to sugars
- Nature 464(7286):169 (2010)
If evolution has had trouble making effective carbohydrate receptors, what hope do humans have of creating synthetic versions? A method for preparing libraries of such receptors boosts the chances of success. - Sex determination: An avian sexual revolution
- Nature 464(7286):171 (2010)
Hormones are not all-powerful in determining whether birds develop with male or female features. Chickens that are genetic sexual mosaics reveal that individual cells also have a say in the matter. - Applied ecology: Grass and the X factor
- Nature 464(7286):172 (2010)
Abstract - Cosmology: Gravity tested on cosmic scales
- Nature 464(7286):172 (2010)
Einstein's theory of general relativity has been tested — and confirmed — on scales far beyond those of our Solar System. But the results don't exclude all alternative theories of gravity. - Exotic matter
- Nature 464(7286):175 (2010)
A 'supersolid' is a quantum solid in which a fraction of the mass is superfluid. As a remarkable consequence, it is rigid, but part of its mass is able to flow owing to quantum physical processes. This paradoxical state of matter was considered as a theoretical possibility as early as 1969, but its existence was discovered only in 2004, in 4He. Since then, intense experimental and theoretical efforts have been made to explain the origins of this exotic state of matter. It now seems that its physical interpretation is more complicated than originally thought. - The enigma of supersolidity
- Nature 464(7286):176 (2010)
A 'supersolid' is a quantum solid in which a fraction of the mass is superfluid. As a remarkable consequence, it is rigid, but part of its mass is able to flow owing to quantum physical processes. This paradoxical state of matter was considered as a theoretical possibility as early as 1969, but its existence was discovered only in 2004, in 4He. Since then, intense experimental and theoretical efforts have been made to explain the origins of this exotic state of matter. It now seems that its physical interpretation is more complicated than originally thought. - Superconductivity gets an iron boost
- Nature 464(7286):183 (2010)
Superconductivity, the resistance-free flow of electrical charges, is one of the most exotic phenomena in solid-state physics. Even though it was discovered almost a century ago, many questions remain unanswered, in particular those concerning the physics of high-temperature superconductivity. The recent discovery of iron-based superconductors was arguably the most important breakthrough in this field for more than two decades and may provide new avenues for understanding this high-temperature phenomenon. Here I present my view of the recent developments in this field that have led to the current understanding of this important new class of superconductor. - Non-Abelian states of matter
- Nature 464(7286):187 (2010)
Quantum mechanics classifies all elementary particles as either fermions or bosons, and this classification is crucial to the understanding of a variety of physical systems, such as lasers, metals and superconductors. In certain two-dimensional systems, interactions between electrons or atoms lead to the formation of quasiparticles that break the fermion–boson dichotomy. A particularly interesting alternative is offered by 'non-Abelian' states of matter, in which the presence of quasiparticles makes the ground state degenerate, and interchanges of identical quasiparticles shift the system between different ground states. Present experimental studies attempt to identify non-Abelian states in systems that manifest the fractional quantum Hall effect. If such states can be identified, they may become useful for quantum computation. - The birth of topological insulators
- Nature 464(7286):194 (2010)
Certain insulators have exotic metallic states on their surfaces. These states are formed by topological effects that also render the electrons travelling on such surfaces insensitive to scattering by impurities. Such topological insulators may provide new routes to generating novel phases and particles, possibly finding uses in technological applications in spintronics and quantum computing. - Spin liquids in frustrated magnets
- Nature 464(7286):199 (2010)
Frustrated magnets are materials in which localized magnetic moments, or spins, interact through competing exchange interactions that cannot be simultaneously satisfied, giving rise to a large degeneracy of the system ground state. Under certain conditions, this can lead to the formation of fluid-like states of matter, so-called spin liquids, in which the constituent spins are highly correlated but still fluctuate strongly down to a temperature of absolute zero. The fluctuations of the spins in a spin liquid can be classical or quantum and show remarkable collective phenomena such as emergent gauge fields and fractional particle excitations. This exotic behaviour is now being uncovered in the laboratory, providing insight into the properties of spin liquids and challenges to the theoretical description of these materials. - Electron liquids and solids in one dimension
- Nature 464(7286):209 (2010)
Even though bulk metallic systems contain a very large number of strongly interacting electrons, their properties are well described within Landau's Fermi liquid theory of non-interacting quasiparticles. Although many higher-dimensional systems can be successfully understood on the basis of such non-interacting theories, this is not possible for one-dimensional systems. When confined to narrow channels, electron interaction gives rise to such exotic phenomena as spin–charge separation and the emergence of correlated-electron insulators. Such strongly correlated electronic behaviour has recently been seen in experiments on one-dimensional carbon nanotubes and nanowires, and this behaviour challenges the theoretical description of such systems. - Targeting early infection to prevent HIV-1 mucosal transmission
- Nature 464(7286):217 (2010)
Measures to prevent sexual mucosal transmission of human immunodeficiency virus (HIV)-1 are urgently needed to curb the growth of the acquired immunodeficiency syndrome (AIDS) pandemic and ultimately bring it to an end. Studies in animal models and acute HIV-1 infection reviewed here reveal potential viral vulnerabilities at the mucosal portal of entry in the earliest stages of infection that might be most effectively targeted by vaccines and microbicides, thereby preventing acquisition and averting systemic infection, CD4 T-cell depletion and pathologies that otherwise rapidly ensue. - Immunology and the elusive AIDS vaccine
- Nature 464(7286):224 (2010)
Developing a human immunodeficiency virus (HIV) vaccine is critical to end the global acquired immunodeficiency syndrome (AIDS) epidemic, but many question whether this goal is achievable. Natural immunity is not protective, and despite immunogenicity of HIV vaccine candidates, human trials have exclusively yielded disappointing results. Nevertheless, there is an indication that success may be possible, but this will be dependent on understanding the antiviral immune response in unprecedented depth to identify and engineer the types of immunity required. Here we outline fundamental immunological questions that need to be answered to develop a protective HIV vaccine, and the immediate need to harness a much broader scientific community to achieve this goal. - Retroviral intasome assembly and inhibition of DNA strand transfer
- Nature 464(7286):232 (2010)
Integrase is an essential retroviral enzyme that binds both termini of linear viral DNA and inserts them into a host cell chromosome. The structure of full-length retroviral integrase, either separately or in complex with DNA, has been lacking. Furthermore, although clinically useful inhibitors of HIV integrase have been developed, their mechanism of action remains speculative. Here we present a crystal structure of full-length integrase from the prototype foamy virus in complex with its cognate DNA. The structure shows the organization of the retroviral intasome comprising an integrase tetramer tightly associated with a pair of viral DNA ends. All three canonical integrase structural domains are involved in extensive protein–DNA and protein–protein interactions. The binding of strand-transfer inhibitors displaces the reactive viral DNA end from the active site, disarming the viral nucleoprotein complex. Our findings define the structural basis of retroviral DNA in! tegration, and will allow modelling of the HIV-1 intasome to aid in the development of antiretroviral drugs. - Somatic sex identity is cell autonomous in the chicken
- Nature 464(7286):237 (2010)
In the mammalian model of sex determination, embryos are considered to be sexually indifferent until the transient action of a sex-determining gene initiates gonadal differentiation. Although this model is thought to apply to all vertebrates, this has yet to be established. Here we have examined three lateral gynandromorph chickens (a rare, naturally occurring phenomenon in which one side of the animal appears male and the other female) to investigate the sex-determining mechanism in birds. These studies demonstrated that gynandromorph birds are genuine male:female chimaeras, and indicated that male and female avian somatic cells may have an inherent sex identity. To test this hypothesis, we transplanted presumptive mesoderm between embryos of reciprocal sexes to generate embryos containing male:female chimaeric gonads. In contrast to the outcome for mammalian mixed-sex chimaeras, in chicken mixed-sex chimaeras the donor cells were excluded from the functional structur! es of the host gonad. In an example where female tissue was transplanted into a male host, donor cells contributing to the developing testis retained a female identity and expressed a marker of female function. Our study demonstrates that avian somatic cells possess an inherent sex identity and that, in birds, sexual differentiation is substantively cell autonomous. - Systems survey of endocytosis by multiparametric image analysis
Collinet C Stöter M Bradshaw CR Samusik N Rink JC Kenski D Habermann B Buchholz F Henschel R Mueller MS Nagel WE Fava E Kalaidzidis Y Zerial M - Nature 464(7286):243 (2010)
Endocytosis is a complex process fulfilling many cellular and developmental functions. Understanding how it is regulated and integrated with other cellular processes requires a comprehensive analysis of its molecular constituents and general design principles. Here, we developed a new strategy to phenotypically profile the human genome with respect to transferrin (TF) and epidermal growth factor (EGF) endocytosis by combining RNA interference, automated high-resolution confocal microscopy, quantitative multiparametric image analysis and high-performance computing. We identified several novel components of endocytic trafficking, including genes implicated in human diseases. We found that signalling pathways such as Wnt, integrin/cell adhesion, transforming growth factor (TGF)-β and Notch regulate the endocytic system, and identified new genes involved in cargo sorting to a subset of signalling endosomes. A systems analysis by Bayesian networks further showed that the n! umber, size, concentration of cargo and intracellular position of endosomes are not determined randomly but are subject to specific regulation, thus uncovering novel properties of the endocytic system. - The primary transcriptome of the major human pathogen Helicobacter pylori
Sharma CM Hoffmann S Darfeuille F Reignier J Findeiß S Sittka A Chabas S Reiche K Hackermüller J Reinhardt R Stadler PF Vogel J - Nature 464(7286):250 (2010)
Genome sequencing of Helicobacter pylori has revealed the potential proteins and genetic diversity of this prevalent human pathogen, yet little is known about its transcriptional organization and noncoding RNA output. Massively parallel cDNA sequencing (RNA-seq) has been revolutionizing global transcriptomic analysis. Here, using a novel differential approach (dRNA-seq) selective for the 5′ end of primary transcripts, we present a genome-wide map of H. pylori transcriptional start sites and operons. We discovered hundreds of transcriptional start sites within operons, and opposite to annotated genes, indicating that complexity of gene expression from the small H. pylori genome is increased by uncoupling of polycistrons and by genome-wide antisense transcription. We also discovered an unexpected number of ~60 small RNAs including the ϵ-subdivision counterpart of the regulatory 6S RNA and associated RNA products, and potential regulators of cis- and trans-encoded targ! et messenger RNAs. Our approach establishes a paradigm for mapping and annotating the primary transcriptomes of many living species. - Confirmation of general relativity on large scales from weak lensing and galaxy velocities
- Nature 464(7286):256 (2010)
Although general relativity underlies modern cosmology, its applicability on cosmological length scales has yet to be stringently tested. Such a test has recently been proposed1, using a quantity, EG, that combines measures of large-scale gravitational lensing, galaxy clustering and structure growth rate. The combination is insensitive to 'galaxy bias' (the difference between the clustering of visible galaxies and invisible dark matter) and is thus robust to the uncertainty in this parameter. Modified theories of gravity generally predict values of EG different from the general relativistic prediction because, in these theories, the 'gravitational slip' (the difference between the two potentials that describe perturbations in the gravitational metric) is non-zero, which leads to changes in the growth of structure2 and the strength of the gravitational lensing effect3. Here we report that EG = 0.39 ± 0.06 on length scales of tens of megaparsecs, in agreemen! t with the general relativistic prediction of EG ≈ 0.4. The measured value excludes a model1 within the tensor–vector–scalar gravity theory4, 5, which modifies both Newtonian and Einstein gravity. However, the relatively large uncertainty still permits models within f() theory6, which is an extension of general relativity. A fivefold decrease in uncertainty is needed to rule out these models. - Deviations from a uniform period spacing of gravity modes in a massive star
- Nature 464(7286):259 (2010)
The life of a star is dominantly determined by the physical processes in the stellar interior. Unfortunately, we still have a poor understanding of how the stellar gas mixes near the stellar core, preventing precise predictions of stellar evolution1. The unknown nature of the mixing processes as well as the extent of the central mixed region is particularly problematic for massive stars2. Oscillations in stars with masses a few times that of the Sun offer a unique opportunity to disentangle the nature of various mixing processes, through the distinct signature they leave on period spacings in the gravity mode spectrum3. Here we report the detection of numerous gravity modes in a young star with a mass of about seven solar masses. The mean period spacing allows us to estimate the extent of the convective core, and the clear periodic deviation from the mean constrains the location of the chemical transition zone to be at about 10 per cent of the radius and rules out a cl! ear-cut profile. - Transmission of electrical signals by spin-wave interconversion in a magnetic insulator
- Nature 464(7286):262 (2010)
The energy bandgap of an insulator is large enough to prevent electron excitation and electrical conduction1. But in addition to charge, an electron also has spin2, and the collective motion of spin can propagate—and so transfer a signal—in some insulators3. This motion is called a spin wave and is usually excited using magnetic fields. Here we show that a spin wave in an insulator can be generated and detected using spin-Hall effects, which enable the direct conversion of an electric signal into a spin wave, and its subsequent transmission through (and recovery from) an insulator over macroscopic distances. First, we show evidence for the transfer of spin angular momentum between an insulator magnet Y3Fe5O12 and a platinum film. This transfer allows direct conversion of an electric current in the platinum film to a spin wave in the Y3Fe5O12 via spin-Hall effects4, 5, 6, 7, 8, 9, 10, 11. Second, making use of the transfer in a Pt/Y3Fe5O12/Pt system, we demonstrate ! that an electric current in one metal film induces voltage in the other, far distant, metal film. Specifically, the applied electric current is converted into spin angular momentum owing to the spin-Hall effect7, 8, 10, 11 in the first platinum film; the angular momentum is then carried by a spin wave in the insulating Y3Fe5O12 layer; at the distant platinum film, the spin angular momentum of the spin wave is converted back to an electric voltage. This effect can be switched on and off using a magnetic field. Weak spin damping3 in Y3Fe5O12 is responsible for its transparency for the transmission of spin angular momentum. This hybrid electrical transmission method potentially offers a means of innovative signal delivery in electrical circuits and devices. - Tunable polymer multi-shape memory effect
- Nature 464(7286):267 (2010)
Shape memory polymers are materials that can memorize temporary shapes and revert to their permanent shape upon exposure to an external stimulus such as heat1, light2, 3, moisture4 or magnetic field5. Such properties have enabled a variety of applications including deployable space structures6, biomedical devices7, 8, adaptive optical devices9, smart dry adhesives10 and fasteners11. The ultimate potential for a shape memory polymer, however, is limited by the number of temporary shapes it can memorize in each shape memory cycle and the ability to tune the shape memory transition temperature(s) for the targeted applications. Currently known shape memory polymers are capable of memorizing one or two temporary shapes, corresponding to dual- and triple-shape memory effects (also counting the permanent shape), respectively11, 12, 13. At the molecular level, the maximum number of temporary shapes a shape memory polymer can memorize correlates directly to the number of discre! te reversible phase transitions (shape memory transitions) in the polymer11, 12, 13. Intuitively, one might deduce that multi-shape memory effects are achievable simply by introducing additional reversible phase transitions. The task of synthesizing a polymer with more than two distinctive and strongly bonded13 reversible phases, however, is extremely challenging. Tuning shape memory effects, on the other hand, is often achieved through tailoring the shape memory transition temperatures, which requires alteration in the material composition14, 15, 16. Here I show that the perfluorosulphonic acid ionomer (PFSA), which has only one broad reversible phase transition, exhibits dual-, triple-, and at least quadruple-shape memory effects, all highly tunable without any change to the material composition. - A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry
- Nature 464(7286):271 (2010)
Halogen atoms and oxides are highly reactive and can profoundly affect atmospheric composition. Chlorine atoms can decrease the lifetimes of gaseous elemental mercury1 and hydrocarbons such as the greenhouse gas methane2. Chlorine atoms also influence cycles that catalytically destroy or produce tropospheric ozone3, a greenhouse gas potentially toxic to plant and animal life. Conversion of inorganic chloride into gaseous chlorine atom precursors within the troposphere is generally considered a coastal or marine air phenomenon4. Here we report mid-continental observations of the chlorine atom precursor nitryl chloride at a distance of 1,400 km from the nearest coastline. We observe persistent and significant nitryl chloride production relative to the consumption of its nitrogen oxide precursors. Comparison of these findings to model predictions based on aerosol and precipitation composition data from long-term monitoring networks suggests nitryl chloride production in! the contiguous USA alone is at a level similar to previous global estimates for coastal and marine regions5. We also suggest that a significant fraction of tropospheric chlorine atoms6 may arise directly from anthropogenic pollutants. - Antagonistic coevolution accelerates molecular evolution
- Nature 464(7286):275 (2010)
The Red Queen hypothesis proposes that coevolution of interacting species (such as hosts and parasites) should drive molecular evolution through continual natural selection for adaptation and counter-adaptation1, 2, 3. Although the divergence observed at some host-resistance4, 5, 6 and parasite-infectivity7, 8, 9 genes is consistent with this, the long time periods typically required to study coevolution have so far prevented any direct empirical test. Here we show, using experimental populations of the bacterium Pseudomonas fluorescens SBW25 and its viral parasite, phage Φ2 (refs 10, 11), that the rate of molecular evolution in the phage was far higher when both bacterium and phage coevolved with each other than when phage evolved against a constant host genotype. Coevolution also resulted in far greater genetic divergence between replicate populations, which was correlated with the range of hosts that coevolved phage were able to infect. Consistent with this, the mo! st rapidly evolving phage genes under coevolution were those involved in host infection. These results demonstrate, at both the genomic and phenotypic level, that antagonistic coevolution is a cause of rapid and divergent evolution, and is likely to be a major driver of evolutionary change within species. - Compensatory evolution in mitochondrial tRNAs navigates valleys of low fitness
- Nature 464(7286):279 (2010)
A long-standing controversy in evolutionary biology is whether or not evolving lineages can cross valleys on the fitness landscape that correspond to low-fitness genotypes, which can eventually enable them to reach isolated fitness peaks1, 2, 3, 4, 5, 6, 7, 8, 9. Here we study the fitness landscapes traversed by switches between different AU and GC Watson–Crick nucleotide pairs at complementary sites of mitochondrial transfer RNA stem regions in 83 mammalian species. We find that such Watson–Crick switches occur 30–40 times more slowly than pairs of neutral substitutions, and that alleles corresponding to GU and AC non-Watson–Crick intermediate states segregate within human populations at low frequencies, similar to those of non-synonymous alleles. Substitutions leading to a Watson–Crick switch are strongly correlated, especially in mitochondrial tRNAs encoded on the GT-nucleotide-rich strand of the mitochondrial genome. Using these data we estimate that a ty! pical Watson–Crick switch involves crossing a fitness valley of a depth of about 10-3 or even about 10-2, with AC intermediates being slightly more deleterious than GU intermediates. This compensatory evolution must proceed through rare intermediate variants that never reach fixation2. The ubiquitous nature of compensatory evolution in mammalian mitochondrial tRNAs and other molecules10, 11 implies that simultaneous fixation of two alleles that are individually deleterious may be a common phenomenon at the molecular level. - Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards
Lutes AA Neaves WB Baumann DP Wiegraebe W Baumann P - Nature 464(7286):283 (2010)
Although bisexual reproduction has proven to be highly successful, parthenogenetic all-female populations occur frequently in certain taxa, including the whiptail lizards of the genus Aspidoscelis. Allozyme analysis revealed a high degree of fixed heterozygosity in these parthenogenetic species1, 2, supporting the view that they originated from hybridization events between related sexual species. It has remained unclear how the meiotic program is altered to produce diploid eggs while maintaining heterozygosity. Here we show that meiosis commences with twice the number of chromosomes in parthenogenetic versus sexual species, a mechanism that provides the basis for generating gametes with unreduced chromosome content without fundamental deviation from the classic meiotic program. Our observation of synaptonemal complexes and chiasmata demonstrate that a typical meiotic program occurs and that heterozygosity is not maintained by bypassing recombination. Instead, fluoresce! nt in situ hybridization probes that distinguish between homologues reveal that bivalents form between sister chromosomes, the genetically identical products of the first of two premeiotic replication cycles. Sister chromosome pairing provides a mechanism for the maintenance of heterozygosity, which is critical for offsetting the reduced fitness associated with the lack of genetic diversity in parthenogenetic species. - Systematic genetic analysis of muscle morphogenesis and function in Drosophila
- Nature 464(7286):287 (2010)
Systematic genetic approaches have provided deep insight into the molecular and cellular mechanisms that operate in simple unicellular organisms. For multicellular organisms, however, the pleiotropy of gene function has largely restricted such approaches to the study of early embryogenesis. With the availability of genome-wide transgenic RNA interference (RNAi) libraries in Drosophila1, 2, it is now possible to perform a systematic genetic dissection of any cell or tissue type at any stage of the lifespan. Here we apply these methods to define the genetic basis for formation and function of the Drosophila muscle. We identify a role in muscle for 2,785 genes, many of which we assign to specific functions in the organization of muscles, myofibrils or sarcomeres. Many of these genes are phylogenetically conserved, including genes implicated in mammalian sarcomere organization and human muscle diseases. - Telomere elongation in induced pluripotent stem cells from dyskeratosis congenita patients
Agarwal S Loh YH McLoughlin EM Huang J Park IH Miller JD Huo H Okuka M Dos Reis RM Loewer S Ng HH Keefe DL Goldman FD Klingelhutz AJ Liu L Daley GQ - Nature 464(7286):292 (2010)
Patients with dyskeratosis congenita (DC), a disorder of telomere maintenance, suffer degeneration of multiple tissues1, 2, 3. Patient-specific induced pluripotent stem (iPS) cells4 represent invaluable in vitro models for human degenerative disorders like DC. A cardinal feature of iPS cells is acquisition of indefinite self-renewal capacity, which is accompanied by induction of the telomerase reverse transcriptase gene (TERT)5, 6, 7. We investigated whether defects in telomerase function would limit derivation and maintenance of iPS cells from patients with DC. Here we show that reprogrammed DC cells overcome a critical limitation in telomerase RNA component (TERC) levels to restore telomere maintenance and self-renewal. We discovered that TERC upregulation is a feature of the pluripotent state, that several telomerase components are targeted by pluripotency-associated transcription factors, and that in autosomal dominant DC, transcriptional silencing accompanies a 3�! �� deletion at the TERC locus. Our results demonstrate that reprogramming restores telomere elongation in DC cells despite genetic lesions affecting telomerase, and show that strategies to increase TERC expression may be therapeutically beneficial in DC patients. - The cells and peripheral representation of sodium taste in mice
Chandrashekar J Kuhn C Oka Y Yarmolinsky DA Hummler E Ryba NJ Zuker CS - Nature 464(7286):297 (2010)
Salt taste in mammals can trigger two divergent behavioural responses. In general, concentrated saline solutions elicit robust behavioural aversion, whereas low concentrations of NaCl are typically attractive, particularly after sodium depletion1, 2, 3, 4, 5. Notably, the attractive salt pathway is selectively responsive to sodium and inhibited by amiloride, whereas the aversive one functions as a non-selective detector for a wide range of salts1, 2, 3, 6, 7, 8, 9. Because amiloride is a potent inhibitor of the epithelial sodium channel (ENaC), ENaC has been proposed to function as a component of the salt-taste-receptor system1, 3, 6, 7, 8, 9, 10, 11, 12, 13, 14. Previously, we showed that four of the five basic taste qualities—sweet, sour, bitter and umami—are mediated by separate taste-receptor cells (TRCs) each tuned to a single taste modality, and wired to elicit stereotypical behavioural responses5, 15, 16, 17, 18. Here we show that sodium sensing is also medi! ated by a dedicated population of TRCs. These taste cells express the epithelial sodium channel ENaC19, 20, and mediate behavioural attraction to NaCl. We genetically engineered mice lacking ENaCα in TRCs, and produced animals exhibiting a complete loss of salt attraction and sodium taste responses. Together, these studies substantiate independent cellular substrates for all five basic taste qualities, and validate the essential role of ENaC for sodium taste in mice. - B-cell-derived lymphotoxin promotes castration-resistant prostate cancer
- Nature 464(7286):302 (2010)
Prostate cancer (CaP) progresses from prostatic intraepithelial neoplasia through locally invasive adenocarcinoma to castration-resistant metastatic carcinoma1. Although radical prostatectomy, radiation and androgen ablation are effective therapies for androgen-dependent CaP, metastatic castration-resistant CaP is a major complication with high mortality2. Androgens stimulate growth and survival of prostate epithelium and early CaP. Although most patients initially respond to androgen ablation, many develop castration-resistant CaP within 12–18 months2. Despite extensive studies, the mechanisms underlying the emergence of castration-resistant CaP remain poorly understood and their elucidation is critical for developing improved therapies. Curiously, castration-resistant CaP remains androgen-receptor dependent, and potent androgen-receptor antagonists induce tumour regression in castrated mice3. The role of inflammation in castration-resistant CaP has not been addre! ssed, although it was reported that intrinsic NF-κB activation supports its growth4. Inflammation is a localized protective reaction to injury or infection, but it also has a pathogenic role in many diseases, including cancer5. Whereas acute inflammation is critical for host defence, chronic inflammation contributes to tumorigenesis and metastatic progression. The inflammation-responsive IκB kinase (IKK)-β and its target NF-κB have important tumour-promoting functions within malignant cells and inflammatory cells6. The latter, including macrophages and lymphocytes, are important elements of the tumour microenvironment7, 8, 9, but the mechanisms underlying their recruitment remain obscure, although they are thought to depend on chemokine and cytokine production10. We found that CaP progression is associated with inflammatory infiltration and activation of IKK-α, which stimulates metastasis by an NF-κB-independent, cell autonomous mechanism11. Here we show that androgen! ablation causes infiltration of regressing androgen-dependent! tumours with leukocytes, including B cells, in which IKK-β activation results in production of cytokines that activate IKK-α and STAT3 in CaP cells to enhance hormone-free survival. - JARID2 regulates binding of the Polycomb repressive complex 2 to target genes in ES cells
Pasini D Cloos PA Walfridsson J Olsson L Bukowski JP Johansen JV Bak M Tommerup N Rappsilber J Helin K - Nature 464(7286):306 (2010)
The Polycomb group (PcG) proteins have an important role in controlling the expression of genes essential for development, differentiation and maintenance of cell fates1, 2. The Polycomb repressive complex 2 (PRC2) is believed to regulate transcriptional repression by catalysing the di- and tri-methylation of lysine 27 on histone H3 (H3K27me2/3)2. At present, it is unknown how the PcG proteins are recruited to their target promoters in mammalian cells3. Here we show that PRC2 forms a stable complex with the Jumonji- and ARID-domain-containing protein, JARID2 (ref. 4). Using genome-wide location analysis, we show that JARID2 binds to more than 90% of previously mapped PcG target genes. Notably, we show that JARID2 is sufficient to recruit PcG proteins to a heterologous promoter, and that inhibition of JARID2 expression leads to a major loss of PcG binding and to a reduction of H3K27me3 levels on target genes. Consistent with an essential role for PcG proteins in early! development5, 6, 7, 8, we demonstrate that JARID2 is required for the differentiation of mouse embryonic stem cells. Thus, these results demonstrate that JARID2 is essential for the binding of PcG proteins to target genes and, consistent with this, for the proper differentiation of embryonic stem cells and normal development. - The Omniplus Ultra
- Nature 464(7286):316 (2010)
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