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This press release is copyright Nature.
VOL.468 NO.7322 DATED 18 NOVEMBER 2010
This press release contains:
· Summaries of newsworthy papers:
Ecology: Marine biodiversity measure caught out
Physics: Antihydrogen in captivity
Opinion: Time to stop economic growth
Opinion: The end of cheap coal is nigh
Neuroscience: Retrotransposons make their mark
Materials science: Porous silica films with a twist
Physics: A four-fold quantum network
And finally… Coming in from the cold
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Ecology: Marine biodiversity measure caught out (pp 431- 435; N&V)
A widely used indicator of marine biodiversity, the mean trophic level from fishery catches (catch MTL), may not be an accurate reflection of the true impact of fishing on marine ecosystems. The findings are reported in this week’s Nature.
The health of marine ecosystems is usually measured using catch MTL, which is meant to detect shifts from top-level predators like cod to low-trophic-level invertebrates and plankton, and which is interpreted as a way to track changes in the underlying ecosystem.
Trevor Branch and colleagues combine models from 25 global ecosystems and empirical comparisons of catch MTL with the MTL of the ecosystem. They find that, in contrast to previous findings, catch MTL does not reliably predict changes in marine ecosystems, such as the collapse of predators. In the Gulf of Thailand, for example, almost all fished species collapsed and the MTL of surveyed species declined but catch MTL increased continuously.
A means of evaluating the impact of fishing on biodiversity is necessary to assess the success or failure of ecosystem management strategies. The authors advocate for a greater emphasis on tracking trends in the true abundance of marine species, particularly those vulnerable to depletion.
CONTACT
Trevor Branch (University of Washington, Seattle, WA, USA)
Tel: +1 206 221 5457; E-mail: [email protected]
Joseph Powers (Louisiana State University, Baton Rouge, LA, USA) N&V author
Tel: +1 225 578 7659; E-mail: [email protected]
[2] Physics: Antihydrogen in captivity (AOP)
DOI: 10.1038/nature09610
***This paper will be published electronically on Nature's website on 17 November at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 18 November, but at a later date. ***
An experiment at CERN, the European Organization for Nuclear Research, has demonstrated the trapping and controlled release of atoms of antihydrogen. The achievement, reported in this week’s Nature, opens the door to precision tests of nature’s fundamental symmetries.
The standard model of particle physics invokes the existence of some basic symmetries in the operation of physical laws. According to these symmetries, the spectrum of antihydrogen — the bound state of an antiproton and a positron — should be identical to that of hydrogen. Antihydrogen has been produced at low energies at CERN since 2002, but until now it has not been possible to confine these neutral atoms, preventing detailed study of the spectrum.
Jeffrey Hangst and colleagues now report the trapping and subsequent detection of 38 atoms of antihydrogen, and describe some of the technical innovations that have made this possible. These include ways to cool the positrons and antiprotons sufficiently to form anti-atoms with effective temperatures of less than about half a kelvin and a newly designed magnetic trap that confines the neutral atoms by interacting with their magnetic moments. With further work, both the trapping time (currently at least 170 milliseconds) and the fraction of atoms trapped (about 0.005%) should increase.
CONTACT
Jeffrey Hangst (Aarhus University, Denmark)
Tel: +41 76 487 4589; E-mail: [email protected]
Opinion: Time to stop economic growth (pp 370-371)
Nearly all nations responded to the recent financial crisis with desperate measures to resume economic growth. But this is a bad idea, argues Peter Victor in a Comment article in Nature this week.
The pursuit of economic growth in the developed world has led to climate change, biodiversity loss, poor public health and social unrest, while doing little to increase human welfare, argues Victor. The suggestion that developed countries should abandon economic growth is regarded by many as heresy. Yet a growing number of scholars, policy-makers and citizens are coming round to the idea of steady-state or ‘degrowth’ economies. They point out that economic growth only became a policy priority in its own right in the 1950s. It’s time for that to change, argues Victor: “Economists and other social scientists now need to map out functional economies in which growth is sidelined, and stability, resilience and wellbeing are the prime objectives, within environmental and resource constraints”.
Victor has built a model of the Canadian economy to show how employment can be increased, poverty and greenhouse-gas emissions reduced, and government debt effectively managed, all without economic growth. A key ingredient is a 15% shorter work year by 2035, which would help spread employment among a larger portion of the labour force, and convert economic efficiency into leisure time, rather than into GDP. Similar investigations are under way or proposed in New Zealand, Austria, the United Kingdom, Finland and the United States. Victor rounds up the evidence, and calls for others to join the campaign, concluding “done thoughtfully, this could lead to more satisfactory and fulfilling lives for all”.
CONTACT
Peter Victor (York University, Toronto, Ontario, Canada)
Tel: +1 416 769 6133; E-mail: [email protected]
Opinion: The end of cheap coal is nigh (pp 367-369)
The idea that coal is cheap and plentiful drives much thinking about future world energy consumption. It can explain the resistance of the United States and China to carbon-cutting policies — both countries have lots of coal, and they don’t plan to stop using it anytime soon. But is it a reasonable assumption? Richard Heinberg and David Fridley argue in this week’s Nature that coal prices are likely to start rising much sooner than everyone thinks — perhaps by the end of this decade.
This prediction is based on two observations. First, several recent studies suggest that high-quality accessible coal reserves will run out much sooner than predicted by official forecasts from the main coal-producing countries. Second, global demand is growing rapidly, mainly driven by China. China is both the world’s biggest producer of coal and its biggest consumer. “Its influence on future coal prices should not be underestimated,” say the authors.
The authors call for better data on world coal supplies. A US national coal survey was last completed in the 1970s and is long overdue. Countries should also immediately start planning for higher coal prices, and reconsider their investments in clean-coal technology. If coal becomes more expensive, then carbon capture and storage will no be longer be an economically viable route to reducing carbon emissions. The economic shocks from rising prices would be felt by every sector of society, say Heinberg and Fridley. New limits on energy consumption “will be imposed by energy prices and shortages if they are not achieved though planning and policy”.
CONTACT
Tod Brilliant (Communications Director, Post Carbon Institute, Santa Rosa, CA, USA)
Tel: +1 707 823 8700 x105; Mobile: +1 707 235 1026; Email: [email protected]
[3] Neuroscience: Retrotransposons make their mark (pp 443-446; N&V)
A gene previously implicated in the neurodevelopmental disorder Rett syndrome may influence the activity of certain retrotransposons, genetic elements that influence gene expression and neuronal function. The find, reported in this week’s Nature, adds an extra layer of complexity to our understanding of molecular neurological disorders.
Mutations in the MECP2 gene can cause Rett syndrome (RTT), a disorder characterized by compulsive, stereotyped behaviours, seizures and motor abnormalities. Cells derived from MECP2 mutation-carrying RTT patients show increased levels of L1 retrotransposon activity, Alysson Muotri and colleagues show. And the find is echoed in rodent models, where a lack of MeCP2 goes hand in hand with increased L1 retrotransposon activity.
Retrotransposons, genetic elements that can amplify themselves in a genome, make up around one fifth of mammalian genomes. Whether or not the high rates of neuronal retrotransposition seen in this study are a consequence or a cause of the disease process is unknown. But nonetheless, it is thought that new genetic insertions, especially at early developmental stages, could influence neuronal functioning in later life.
CONTACT
Alysson Muotri (University of California, San Diego, CA, USA)
Tel: +1 858 534 9320; E-mail: [email protected]
Lorenz Studer (Sloan-Kettering Institute for Cancer Research, New York, NY, USA) N&V author
Tel: +1 212 639 6126; E-mail: [email protected]
[4] Materials science: Porous silica films with a twist (pp 422-425; N&V)
The helical structure that gives an iridescent sheen to beetle exoskeletons has now been replicated in porous silica films, by a casting process using nanocrystalline cellulose as a template. As reported in this week’s Nature, the films have tunable optical properties that lend themselves to a variety of applications, and might also serve as hard templates to synthesize other new materials.
Many biological molecules have a handedness, or ‘chirality’, which governs their interactions with matter and light. Liquid crystals with a ‘chiral nematic’ structure, in which rod-shaped molecules or crystals are organized in a helical pattern, selectively reflect circularly polarized light, causing iridescence when the helical pitch is comparable to the wavelength of visible light. Introducing chirality into porous inorganic solids could therefore be useful for photonic applications, as well as for recognizing or separating chiral molecules.
Mark MacLachlan and colleagues have created thin silica films with nanoscale helical pores, by using a chiral nematic phase of nanocrystalline cellulose as a structure-directing template. The films preferentially reflect light of a specific wavelength, which can be tuned across a wide range by varying the synthetic conditions. The authors demonstrate the utility of the combination of nanoscale porosity and chirality by showing how the films’ optical properties can be switched by the absorption and desorption of liquid — a feature that could be used in sensing applications such as ‘smart windows’.
CONTACT
Mark MacLachlan (University of British Columbia, Vancouver, Canada)
Tel: +1 604 822 3070; E-mail: [email protected]
Andreas Stein (University of Minnesota, Minneapolis, MN, USA) N&V author
Tel: +1 612 624 1802; E-mail: [email protected]
[5] Physics: A four-fold quantum network (pp 412-416; N&V)
A physical system that can store quantum-mechanically ‘entangled’ states across four atomic memories, and convert them to entangled states of light for transmission across a network, is described in this week’s Nature.
The ability to generate, store and efficiently transfer entangled states of matter and light is a requirement for the use of quantum networks in practical applications. Because the utility of such networks increases with the number of nodes, the entangled states required for computation will need to be multipartite — that is, stored among multiple memories and transmitted across multiple channels. Although many systems have been developed to create and manipulate bipartite entangled states, demonstrations of multipartite entanglement have been rare, and have not included the ability to map entangled states stored in quantum memories to quantum channels.
Jeff Kimble and colleagues now demonstrate this capability, in a system comprising four atomic memories and four photonic channels. The memories comprise four spatially separated regions in a cloud of cold, trapped caesium atoms; the entangled state is a collective excitation of the spins of these atoms, shared across the four ensembles. After generating the entangled state and storing it for a short time, the authors coherently convert it into an entangled state of light, which comprises a single photon shared across four spatially separated beams. The authors verify true fourfold entanglement in both matter and light, and coherent transfer between the two.
CONTACT
Jeff Kimble (California Institute of Technology, Pasadena, CA, USA)
Tel: +1 626 395 8340; E-mail: [email protected]
Vladan Vuletic (Massachusetts Institutes of Technology, Cambridge, MA, USA) N&V author
Tel: +1 617 324 1174; E-mail: [email protected]
[6] And finally… Coming in from the cold (pp 426-430)
A paper appearing in Nature this week provides a detailed analysis of the March 2010 eruption of Eyjafjallajökull, Iceland, and explains how the magmatic flow inside the volcano led to eruptive activity after almost two centuries of quiescence.
The volcanoes in Iceland form the surface expression of the Mid-Atlantic Ridge system, but Eyjafjallajökull lies away from the main rift zone, so that less magmatic heat is supplied to it than to volcanoes nearer the rift zone. During a typical eruption at a highly active volcano, the magma chamber inside the volcano deflates as pressure is released, which causes deformation on the surface. Until now, scientists have been unclear as to whether eruption and deformation processes at ‘colder’ moderately active volcanoes like Eyjafjallajökull are any different from their hotter and more active neighbours.
Freysteinn Sigmundsson and colleagues used GPS data, satellite radar interferometry and seismic monitoring to track the deformation of Eyjafjallajökull over the last two decades of intermittent volcanic unrest. They found that the deformation of the volcano was unusual, as it did not relate to pressure changes within a single magma chamber. They suggest that a lack of deflation during the eruption might be due to a limited shallow magma supply and the volcano’s off-rift setting with a cold subsurface structure.
CONTACT
Freysteinn Sigmundsson (University of Iceland, Reykjavik, Iceland)
Tel: +354 525 4494; E-mail: [email protected]
ALSO IN THIS ISSUE…
[7] The moment of truth for WIMP dark matter (pp 389-393)
[8] A widespread family of polymorphic contact dependent toxin delivery systems in bacteria (pp 439-442)
[9] 2'-O methylation of the viral mRNA cap evades host restriction by IFIT family members (pp 452-456)
[10] Molecular coupling of Tsix regulation and pluripotency (pp 457-460)
ADVANCE ONLINE PUBLICATION
***These papers will be published electronically on Nature's website on 17 November at 1800 London time / 1300 US Eastern Time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included them on this release to avoid multiple mailings they will not appear in print on 18 November, but at a later date. ***
[11] Acid sensing by the Drosophila olfactory system
DOI: 10.1038/nature09537
[12] Formation, regulation and evolution of Caenorhabditis elegans 3’UTRs
DOI: 10.1038/nature09616
[13] Cap binding and immune evasion revealed by Lassa nucleoprotein structure
DOI: 10.1038/nature09605
[14] Quantitative reactivity profiling predicts functional cysteines in proteomes
DOI: 10.1038/nature09472
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
AUSTRALIA
Hobart: 1
BRAZIL
Rio de Janeiro: 2
CANADA
Burnaby: 2
Calgary: 2
Halifax: 1
Toronto: 2
Vancouver: 1, 2, 4
CHINA
Guangdong: 13
DENMARK
Aarhus: 2
FRANCE
Dijon: 11
Paris: 7, 10, 11
ICELAND
Reykjavik: 6
ISRAEL
Beer Sheva: 2
JAPAN
Ikoma: 3
Saitama: 2
Tokyo: 2
SPAIN
Zaragoza: 10
SWEDEN
Gothenburg: 6
Lausanne: 11
Stockholm: 2
SWITZERLAND
St Gallen: 9
Zurich: 2, 7, 9
THE NETHERLANDS
Delft: 6
UNITED KINGDOM
Edinburgh: 10
Liverpool: 2
Lowestoft: 1
Norwich: 1
Swansea: 2
UNITED STATES OF AMERICA
Alabama
Auburn: 2, 9
California
Berkeley: 2
La Jolla: 3, 14
Pasadena: 5
San Francisco: 12
Santa Barbara: 8
Colorado
Boulder: 5
Georgia
Atlanta: 13
Maryland
Bethesda: 9
Massachusetts
Cambridge: 12
Missouri
St Louis: 9
New York
Albany: 9
New York: 11
North Carolina
Chapel Hill: 8
Ohio
Cleveland: 9
Oregon
Eugene: 5
Pennsylvania
Pittsburgh: 9
Washington
Seattle: 1, 9, 14
Wisconsin
Madison: 6
PRESS CONTACTS…
From North America and Canada
Neda Afsarmanesh, Nature New York
Tel: +1 212 726 9231; E-mail: [email protected]
From Japan, Korea, China, Singapore and Taiwan
Mika Nakano, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
From the UK
Rebecca Walton, Nature, London
Tel: +44 20 7843 4502; E-mail: [email protected]
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