This press release is copyright Nature.
VOL.439 NO.7074 DATED 19 JANUARY 2006
This press release contains:
Summaries of newsworthy papers:
Oceanography: Global warming could destabilize ocean's simplest plants
Nuclear physics: Exploding cigars
Neuroscience: Schadenfreude shows up in the brain
Molecular biology: Making it through the dark nights
Neuroscience: Molecule prompts learning
Astrophysics: Ancient asteroid break-up gives Earth a dusting
Evolution: Listen up, our ears used to be used for breathing
Plant biology: Hunt for hormone machinery bears fruit
Physics: Icy frustration
And finally...Superstretchy nanotubes
Mention of papers to be published at the same time with the same embargo
Geographical listing of authors
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 Oceanography: Global warming could destabilize ocean's simplest plants (pp322-325)
Climate change could disrupt the distribution of phytoplankton, the plants that form the basis of many of the ocean's food chains, according to a new computer model. The analysis suggests that reduced vertical mixing of waters as a result of increasing temperatures could cause the deep-water layers of phytoplankton - previously thought to be stable features - to oscillate and shift.
The plankton bands, called 'deep chlorophyll maxima', form at the optimal point where sunlight filtering down from above meets nutrients welling up from below. A widespread feature of tropical and subtropical oceans, most experts had assumed that they were relatively unchanging.
But the new analysis suggests otherwise, say Jef Huisman and colleagues in this week's Nature. The discovery that these features can show sustained fluctuations shows that they are not as imperturbable as thought - and the fact that these fluctuations are favoured by reduced vertical mixing hints that they could become a reality as global warming continues.
Jef J Huisman (Institute for Biodiversity and Ecosystem Dynamics, Amsterdam, The Netherlands)
Tel: +31 20 525 7085; E-mail: [email protected]
 Nuclear physics: Exploding cigars (pp298-302; N&V)
The first known example of an atom that sheds protons by both one- and two-proton decay is reported in Nature this week.
Radioactive atoms are generally regarded as decaying through the emission of alpha or beta particles, or gamma rays, from their nucleus. But those are not the only ways an unstable atomic nucleus can fall apart. For example, nuclei with an unusually high proportion of protons (positively charged particles) can decay by emitting individual protons. Such proton-rich atoms are rather rare in nature, but can be formed in artificially induced nuclear reactions. The neutral particles called neutrons can be considered as the 'glue' that holds protons together in a nucleus - but if there aren't enough of these neutrons, protons can burst out.
Such behaviour was first seen in 1982. Twenty years later, proton-rich isotopes of iron were found to decay by two-proton radioactivity - that is, by the simultaneous emission of not one but two protons. Now Ivan Mukha and colleagues have found an atom that sheds protons by both one- and two-proton decay.
They have observed this behaviour in an isotope of silver,94Ag, which may decay by two-proton emission into an isotope of rhodium, 92Rh. The researchers calculate that the proton-rich nucleus of 94Ag is highly non-spherical: its unusual ratio of protons to neutrons causes it to become deformed into a cigar shape. Mukha and colleagues say that protons will tend to be ejected preferentially from the 'tips' of the cigar. In the case of two-proton decay, the two particles can emerge either both from the same tip or one from each end.
Dr Ivan Mukha (University of Seville, Seville, Spain)
Tel: +34 954 550 925; E-mail: [email protected]
Professor Juha Aystö (University of Jyväskylä, Jyväskylä, Finland)
Tel: +358 14 260 2350; E-mail: [email protected]
 Neuroscience: Schadenfreude shows up in the brain
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 18 January 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 19 January, but at a later date.***
Fairness of social interactions has a key role in shaping empathic responses to people, according to research published online this week by Nature. Tania Singer and colleagues show that both women and men empathize with the pain of cooperative people. However, if others behave selfishly this link is compromised, in men at least, and empathetic responses are abolished.
The team engaged male and female volunteers in an economic game, in which two confederates played fairly or unfairly, and then measured brain activity while these same volunteers observed the confederates receiving pain. In a finding that echoes recent evidence for altruistic punishment, the authors conclude that in men empathic responses are shaped by valuation of other people's social behaviour, such that they empathize with fair opponents while favouring (and even gaining satisfaction from) the physical punishment of unfair opponents.
The authors argue that this is the first neuroscientific evidence for Schadenfreude, the feeling of satisfaction gained if someone whom we dislike suffers.
Tania Singer (University College London, London, UK)
Tel: +44 20 7679 1138 or +44 7984 496229; Email: [email protected]
Klaas Enno Stephan (University College London, London, UK)
Tel: +44 20 7833 7481 or +44 7958 740535; co-author
 Molecular biology: Making it through the dark nights (pp340-343)
Conditions of constant darkness, such as that endured by mammals during hibernation, can regulate metabolism and initiate torpor, reports a study in this week's Nature. Cheng Chi Lee and colleagues demonstrate that sustained exposure of mice to darkness rather than daily light-dark cycles leads to increased levels of enzymes required for fat degradation. These enzymes help maintain blood glucose levels during torpor.
The authors find that 5'-AMP is a key mediator of the response to constant darkness. Giving synthetic 5'-AMP to mice in normal light-dark conditions induces torpor and the expression of fat catabolism enzymes. During torpor, mammals maintain glucose supply to the brain by changing the primary energy source in peripheral organs from glucose to fatty acids. The authors propose that 5'-AMP is a key regulator of this process, and this mechanism could potentially be used as a therapeutic approach for human obesity and insulin-resistant type-2 diabetes.
Dr Cheng Chi Lee (University of Texas Health Science Center, Houston, TX, USA)
Tel: +1 713 500 6832; E-mail: [email protected]
 Neuroscience: Molecule prompts learning (pp283-289)
Investigators have hit upon a diminutive but influential molecule of RNA that helps regulate the strength of the tiny connections between neurons that are thought to underlie learning and memory.
Over recent years scientists have discovered that snippets of RNA called microRNAs control a plethora of processes in plant and animal development. Now Michael Greenberg and his team report in Nature that one such microRNA, called miR-134, blocks the growth of rat dendritic spines, the neuronal protrusions that receive incoming electrical signals in a synapse. Stimulation of the neurons with a growth factor eliminates this block.
Because the size of dendritic spines is thought to correlate with the strength of the synapse, the results suggest that miR-134, and perhaps other microRNAs, regulate the strengthening and weakening of synapses by which the brain records memories.
Michael Greenberg (Children's Hospital, Boston, MA, USA)
Tel: +1 617 355 8344; E-mail: [email protected]
 Astrophysics: Ancient asteroid break-up gives Earth a dusting (pp295-297)
The occurrence and timing of the collisional destruction of a 150-km-diameter 'main belt' asteroid 8.2 million years ago has been corroborated for the first time, according to a paper published in this week's Nature.
Kenneth Farley and colleagues show that the collision produced a marked increase in the amount of interplanetary dust particles falling to earth, with the increased dust shower lasting for about 1.5 million years. The researchers based their findings on analyses of seafloor sediments. The data show that, durnig this period, essentially all the dust particles falling to earth were from a single source - presumably a fragmented asteroid.
The asteroid break-up is thought to have created the Veritas asteroid family. The event may also be related to the formation of some H-chondrite meteorites (stony iron rich meteorites) that date from the same period.
Kenneth Farley (Caltech, Pasadena, CA, USA)
Tel: +1 626 395 6005/3143; E-mail: [email protected]
 Evolution: Listen up, our ears used to be used for breathing (pp318-321)
Our middle ear began its evolutionary life as a structure used for breathing, say researchers who have studied a 370-million-year-old fossil fish. This ancient species, called Panderichthys, catches evolution in the act of fashioning the modern auditory apparatus used by many animals, including humans. The discovery shows that the starting point for this transformation was a gill opening called the spiracle.
Panderichthys was closely related to the earliest tetrapods, a large group of four-limbed vertebrates that includes humans, explain Martin Brazeau and Per Ahlberg in this week's issue of Nature. Compared with earlier fish species, Panderichthys has an enlarged spiracle, similar in size to those of the earliest tetrapods, they report.
This suggests that our modern middle ear, which contains tiny sound-transmitting bones, evolved from a structure used to ventilate the head, rather than arising directly as a hearing structure or as bony support for the brain, as had previously been suggested.
Martin D. Brazeau (Uppsala University, Uppsala, Sweden)
E-mail: [email protected] Please note we are trying to find a contact number for this author please check the press site for updates.
 Plant biology: Hunt for hormone machinery bears fruit (pp290-294; N&V)
In this week's Nature, biologists reveal a component of plants they have been seeking for over 20 years: a receptor for the hormone abscisic acid.
Abscisic acid helps plants survive drought, extreme temperatures and other stress conditions - but its receptors have eluded researchers. Robert Hill and colleagues present evidence that an RNA-binding protein, called FCA, fits the bill. They show that it binds abscisic acid and that this interaction controls flowering time and processing of other RNA molecules.
The study shows that RNA-binding proteins can be direct hormone targets, and raises the prospect that many other such plant proteins might have previously unrecognized functions as receptors.
Robert Hill (University of Manitoba, Winnipeg, Canada)
Tel: +1 204 474 6087; E-mail: [email protected]
Julian J I Schroeder (Univ of California San Diego, La Jolla, CA, USA)
Tel: +1 858 534 7759; E-mail: [email protected]
 Physics: Icy frustration (pp303-306; N&V)
An array of nanoscale magnets makes an ideal model to study the physics of frustration, according to research published in this week's Nature.
Frustration occurs when opposing interactions compete with each other in a physical system. For example, it's possible to arrange black and white counters around the corners of a square so that they never lie next to a counter of the same colour. But try it on the corners of a triangle, and you will always get two counters of the same colour next to each other - they are 'frustrated', and an array of many triangles will see unusual patterns of black and white counters develop in response to this effect.
This is responsible for the particular positioning of hydrogen atoms in water ice, and magnetic atoms can adopt an analogous 'spin ice' arrangement, where the desire to minimize the repulsion of similar magnetic poles is frustrated by the atoms' positions in the crystal. But spin ice arrangements are only stable below minus 272 degrees Celsius, making them frustratingly tricky to study.
Peter Schiffer and colleagues have now created an artificial spin ice system, effectively made of 800,000 bar magnets each less than a millionth of a metre long.
"Such 'artificial' spin ice, which is stable at room temperature and possesses magnetic moments large enough to be observed directly, offers a new approach to understanding and exploiting the properties of disordered systems," comments Steven Bramwell in a related News and Views article.
Peter P Schiffer (Pennsylvania State University, University Park, PA, USA)
Tel: +1 814 865 5982l; E-mail: [email protected]
Steven T. Bramwell (University College London, London, UK)
Tel: +44 207 679 4648; E-mail: [email protected]
 And finally...Superstretchy nanotubes (p281)
Carbon nanotubes can stretch to almost four times their normal length when they are heated to 2,000 °C, scientists report in a Brief Communication in this week's Nature. This comes as a big surprise because until now these structures were thought to be tough and rigid.
Single-walled carbon nanotubes are just a few billionths of a metre wide, and at normal temperatures they break after stretching to only about 1.15 times their original length. However, J. Y. Huang and colleagues found that at high temperatures these nanotubes start to behave like a plastic. One stretched from 24 nanometres to 91 nanometres in length before it snapped.
The scientists say that this may make the tubes suitable as reinforcing agents in ceramics used at high temperatures.
Jianyu Huang (Boston College, Boston, MA, USA)
Tel: +1 617 552 3586; E-mail: [email protected]
ALSO IN THIS ISSUE...
 Dynamical fracture instabilities due to local hyperelasticity at crack tips (pp307-310)
 Low sea level rise projections from mountain glaciers and icecaps under global warming (pp311-313)
 Thallium isotopic evidence for ferromanganese sediments in the mantle source of Hawaiian basalts (pp314 - 317)
 DNA sequence and analysis of human chromosome 8 (pp331-335)
 Top-down gain control of the auditory space map by gaze control circuitry in the barn owl (pp336-339)
 Oscillations of cyclic AMP in hormone-stimulated insulin-secreting b-cells (pp349-352)
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.
Uppsala: 7, 14, 16
London: 3, 13, 14
California Livermore: 10
Pasadena: 3, 6
Colarado Boulder: 6
Florida Tallahassee: 2
Hawaii Honolulu: 1
Maryland Bethesda: 14
Massachusetts Boston: 5, 14, 10
Cambridge: 10, 11, 14
Minnesota Minneapolis: 9
Pennsylvania University Park: 9
Texas Houston: 4
For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
For the UK/Europe/other countries not listed above
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected]
Zoe Corbyn, Nature London
Tel: +44 20 7843 4658; E-mail: [email protected]
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