This press release contains:
---Summaries of newsworthy papers:
Astronomy: Gas cloud falling into a black hole
Astrophysics: Clues from a recently observed supernova
Comment: Nationalize the Fukushima Daiichi nuclear plant
Cancer: Processes involved in breast cancer metastases
Physiology: What makes the metabolic clock tick
Physics: Good vibrations for microwave amplification
Geoscience: Ups and downs of the Messinian salinity crisis
And finally... New flavours of jam
---Mention of papers to be published at the same time with the same embargo
---Geographical listing of authors
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[1] Astronomy: Gas cloud falling into a black hole (AOP; N&V)
DOI: 10.1038/nature10652
Observations of a gas cloud three times the mass of Earth moving towards a black hole at the centre of the Milky Way are reported in Nature this week. Monitoring the dynamic evolution and radiation of the cloud in the next few years provides an opportunity to reveal some properties of this supermassive black hole.
A bright and compact radio source in the Galactic Centre known as Sagittarius A* is believed to be the location of a supermassive black hole. Over the past few years, Stefan Gillessen and colleagues have watched a dense gas cloud move closer to the accretion zone of Sagittarius A*. They predict that as the cloud continues to fall into the black hole the X-ray emission may become substantially brighter. Moreover, the authors expect to see a giant radiation flare in a few years if the cloud breaks up and feeds gas into the black hole.
CONTACT
Stefan Gillessen (Max Planck Institute for Extraterrestrial Physics, Garching, Germany)
Tel: +49 89 300 003 839; E-mail: [email protected]
Mark Morris (University of California, Los Angeles, CA, USA) N&V author
Tel: +1 310 825 3320; E-mail: [email protected]
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[2] & [3] Astrophysics: Clues from a recently observed supernova (pp 344-350; N&V)
The discovery of a supernova (SN 2011fe) in a nearby galaxy just hours after its explosion provides an opportunity to study features of type Ia supernovae. Although type Ia supernovae offer a means of estimating the changing rate of expansion of the Universe, fundamental details of these systems are poorly understood. Two studies in this week’s Nature use early observations of SN 2011fe and pre-explosion images to constrain the nature of the exploding star and the progenitor system.
Supernova SN 2011fe was observed in the nearby pinwheel galaxy Messier 101 in August 2011. Peter Nugent and colleagues report early observations of this supernova. They find that the exploding star was probably a carbon–oxygen white dwarf and conclude that the companion is most likely to have been a main-sequence ― or hydrogen-burning ― star. An accompanying paper by Weidong Li and co-workers uses archival images of the location of SN 2011fe to determine the physical properties of the companion to the progenitor. Their data rule out luminous red giants and most O and B stars with strong winds (collectively known as ‘helium stars’) as mass-donating companions to the exploding white dwarf.
CONTACT
Weidong Li (University of California, Berkeley, CA, USA) Author paper [2]
Tel: +1 707 933 7918; E-mail: [email protected]
Peter Nugent (Lawrence Berkeley National Laboratory, Berkeley, CA, USA) Author paper [3]
Tel: +1 510 486 6942; E-mail: [email protected]
Mario Hamuy (University of Chile, Santiago, Chile) N&V author
Tel: +56 2 977 1091; E-mail: [email protected]
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Comment: Nationalize the Fukushima Daiichi nuclear plant (pp 313-314)
Two members of Japan’s Diet call for the Fukushima Daiichi nuclear power station to be nationalized. Writing in a Comment article in this week’s Nature, two Members of the House of Representatives, Tomoyuki Taira and former prime minister Yukio Hatoyama, argue that public ownership is essential to bring into the open basic evidence about events that rocked the plant during and after the March 2011 earthquake and tsunami.
As part of an independent committee that is investigating the accident, the politicians describe how various nuclear-industry bodies have been slow or obstructive in providing evidence to help ascertain what has taken place. For example, key passages in a manual from Tokyo Electric Power Company were blacked out in an initial submission to their team, and only reinstated months later.
Major questions remain unresolved, such as whether the nuclear cores are still active, what caused the explosions in the days following the earthquake and to what degree molten fuel has eaten through the reactor bases. The power station must be brought into government hands, they say, so that independent scientists can assess the situation and help to develop adequate long-term responses.
CONTACT
Tomoyuki Taira (Member of the House of Representatives, National Diet of Japan, Tokyo, Japan)
E-mail: [email protected]
Yukio Hatoyama (Member of the House of Representatives, National Diet of Japan, Tokyo, Japan)
E-mail: [email protected]
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[4] Cancer: Processes involved in breast cancer metastases (AOP)
DOI: 10.1038/nature10661
Work revealing important features of metastatic breast cancer is reported in Nature this week. The role of microRNA miR-126, which is often silenced in human cancers, in suppressing breast cancer metastases is outlined. Notably, enhanced expression of genes normally regulated by miR-126 increases the likelihood of developing metastases and reduces metastasis-free survival.
Previous research has identified a set of microRNAs that suppress breast cancer metastasis, although their precise role in cancer progression is unknown. Sohail Tavazoie and colleagues show that miR-126 suppresses breast cancer metastases by regulating the recruitment of endothelial cells, which can support the development of metastatic colonies. This control is achieved through the suppression of several novel pro-angiogenic genes involved in endothelial recruitment. The findings highlight the role of endothelial interactions in metastatic breast cancer and reveal potential therapeutic targets for prevention of metastatic breast cancer.
CONTACT
Sohail Tavazoie (Rockefeller University, New York, NY, USA)
Tel: +1 212 327 7208; E-mail: [email protected]
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[5] Physiology: What makes the metabolic clock tick (AOP)
DOI: 10.1038/nature10700
Circadian clocks can influence metabolic function via hormone-dependent pathways, suggests a Nature paper that has therapeutic relevance.
Mammalian metabolism drums to a 24-hour beat and major hormonal circuits have a linked circadian rhythm. Glucocorticoids, for example, regulate many aspects of physiology, including glucose homeostasis, but how their actions find their rhythm is not known. Ronald Evans and colleagues demonstrate how two clock co-regulators, cryptochromes 1 and 2, interact with the glucocorticoid receptor to influence gene expression and normal metabolic homeostasis.
Glucocorticoids are used clinically to suppress inflammation, but their non-specific mode of action has been linked with various undesirable side effects. Altering the timing of treatment, or combining it with agents that target cryptochromes 1 and/or 2, could help to alleviate these side effects, the authors suggest.
CONTACT
Ronald Evans (The Salk Institute for Biological Studies, La Jolla, CA, USA)
Tel: +1 858 453 4100 ext: 1302; E-mail: [email protected]
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[6] Physics: Good vibrations for microwave amplification (pp 351-354)
A tiny mechanical resonator can be used to amplify weak microwave signals, reports a paper published in Nature this week. The results suggest that mechanical devices could be a useful, low-noise alternative to conventional electrical amplifiers for microwave signal detection and processing.
Sensitive measurement of electrical signals is essential for many communication and detection technologies, and requires amplification of the signal while adding as little noise as possible. A fundamental lower limit to the added noise comes from the existence of quantum fluctuations. Operation close to this quantum limit has so far been achieved only by amplifiers based on superconducting devices.
Francesco Massel and colleagues now demonstrate the potential for quantum-limited amplification by a mechanical device. Their resonating strip, only 8.5 micrometres long and 320 nanometres wide, is set in motion by the pressure of microwave photons. The resulting vibrations amplify the power of an incoming signal by a factor of 300 (25 decibels), while adding only 20 quanta of noise — with further noise reduction expected. Noting the generality and conceptual simplicity of the approach, the authors anticipate that mechanical microwave amplifiers could find a place in various applications using integrated circuits.
CONTACT
Francesco Massel (Aalto University, Finland)
Tel: +358 503 015 566; E-mail: [email protected]
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[7] Geoscience: Ups and downs of the Messinian salinity crisis (pp 359-363)
A dynamic equilibrium between tectonic uplift and erosion may have been responsible for a sustained period of reduced water flow from the Atlantic Ocean into the Mediterranean Sea about six million years ago, according to a study published this week in Nature. A model of these competing processes provides a natural explanation for the large amounts of salt deposited in the Mediterranean at this time, and for the cyclic nature of the deposits.
The period of widespread salt precipitation in the Mediterranean known as the Messinian salinity crisis was initiated by reduced water inflow from the Atlantic, owing to a shallowing of the seaway between the two basins. The amount of salt precipitated seems to require the persistence of this restricted connection over hundreds of thousands of years — a circumstance that has been hard to explain without invoking a fortuitous matching of uplift and changes in sea level.
Daniel Garcia-Castellanos and Antonio Villaseñor have found a solution to this problem, by including erosion in the picture. In a numerical model combining uplift, erosion and a climate-based water budget, they find that shallowing of the connecting seaway due to uplift is counteracted by deepening due to water inflow, allowing a restricted connection to be maintained. The competing processes produce oscillations in Mediterranean sea level and salinity, providing a possible explanation for cyclic salt deposits that had previously been attributed to periodic changes in climate.
CONTACT
Daniel Garcia-Castellanos (Instituto de Cièncias de la Tierra Jaume Almera, Barcelona, Spain)
Tel: +34 617 506 676; E-mail: [email protected]
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[8] And finally... New flavours of jam (pp 355-358; N&V)
Granular materials have a richer repertoire of ‘jammed’ states than has been thought, according to work published in Nature this week. Experiments on collections of frictional grains show qualitative behaviours that were not anticipated by theory or modelling of jamming in systems of ideal, frictionless particles.
Anyone who has walked on a sandy beach knows that granular materials can sometimes resist stress, like a solid, yet at other times flow freely, like a liquid. In the former, jammed, state, the grains are locked together in a rigid network; in the unjammed state, they slip by one another. Simulations of frictionless systems have supported a simple model, in which the transition from the unjammed to the jammed state occurs above a critical value for the packing density of the grains. But the nature of this transition in real granular materials, comprising particles that experience friction, has remained unclear.
Robert Behringer and colleagues performed experiments on frictional, disk-shaped grains, made of a material that allowed them to visualize the forces between the grains. They found that, by applying a pure shear stress (compressing in one direction while allowing expansion in the perpendicular direction), they could induce jamming at densities below the critical value for shear-free (isotropic) jamming. These shear-induced states include a new, ‘fragile’ class, which are neither fully jammed nor unjammed, and resist deformation in some directions but not others.
CONTACT
Robert Behringer (Duke University, Durham, NC, USA)
Tel: +1 919 660 2550; E-mail: [email protected]
Martin van Hecke (Leiden University, Netherlands) N&V author
Tel: +31 71 527 5482; E-mail: [email protected]
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ADVANCE ONLINE PUBLICATION
[9] Implementation of a Toffoli gate with superconducting circuits
DOI: 10.1038/nature10713
[10] DNA-binding factors shape the mouse methylome at distal regulatory regions
DOI: 10.1038/nature10716
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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.
CANADA
Sherbrooke: 9
Toronto: 2, 3
CHILE
Santiago: 1
CHINA
Shanghai: 8
FINLAND
Aalto: 6
Helsinki: 6
GERMANY
Berlin: 5
Garching: 1, 3
Munich: 1
ISRAEL
Rehovot: 2, 3
Tel-Aviv: 2, 3
ITALY
Monteporzio: 3
Padova: 3
Pisa: 3
JAPAN
Kashiwa: 3
NETHERLANDS
Groningen: 5
SPAIN
Barcelona: 7
SWITZERLAND
Basel: 10
Zurich: 9
UNITED KINGDOM
Birkenhead: 3
Oxford: 2, 3
UNITED STATES OF AMERICA
Arizona
Tempe: 2
California
Berkeley: 1, 2, 3
Goleta: 2, 3
La Jolla: 5
Pasadena: 2, 3
Santa Barbara: 2, 3
Hawaii
Honolulu: 2
Illinois
Urbana: 1
Indiana
Fort Wayne: 8
Massachusetts
Cambridge: 9
Waltham: 8
New Hampshire
Hanover: 3
New Jersey
Piscataway: 2
New York
New York: 2, 4
North Carolina
Durham: 8
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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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