Volume 444 Issue 7122, 21 December 2006

Two assessments of the refereeing process highlight challenges for journals.

It's a time of change for Nature's venture into speculative fiction.

Why change your lifestyle when you can pay a company to save your greenhouse-gas emissions for you? Quirin Schiermeier investigates whether carbon offsetting can really save the planet.

Environmentalists hail 'Happy Feet effect'.

Instrumentation problems leave relativity test in the balance.

Critics say trials do not translate well into human studies.

Project aims to mine information on genotypes, phenotypes and lifestyle.

From a jewel-like bird, rarer than any diamond, to the delicately poetic swirls generated inside aircraft engines, the pursuit of knowledge turns up its fair share of beauty. This issue, Nature wraps up the year with an arresting series of images from 2006. We've divided them into the art of the natural world, planet-scapes both domestic and extraterrestrial, and the splendour of modern technology. Just because something enhances our knowledge doesn't mean it can't also be bewitching.

The Pentagon is sinking millions of dollars into developing the next generation of supercomputers — and plans to let non-military scientists and engineers share the benefits. Heidi Ledford reports.

The development of lactose tolerance in sub-Saharan Africa is a fascinating tale of genetic convergence, reports Erika Check.

Kerry Black travelled the world in search of the best surf spots. Then he decided to build them himself — on land. Mark Schrope meets the maverick oceanographer.

Ultraendurance racers torture their bodies and minds to achieve near-impossible physical feats. Is it an exceptional genetic make-up or the vestiges of human evolution? Helen Pearson reports.

Are some ways of measuring scientific quality better than others? Sune Lehmann, Andrew D. Jackson and Benny E. Lautrup analyse the reliability of commonly used methods for comparing citation records.

When we consider the Universe, are we trying to impose order on a meaningless jumble?

The snowflake man

The intestinal bacteria in obese humans and mice differ from those in lean individuals. Are these bacteria involved in how we regulate body weight, and are they a factor in the obesity epidemic?

Gigantic cosmological γ-ray bursts have fallen into a dichotomy of long and short bursts, each with a very different origin. The discovery of an oddball burst calls for a rethink of that classification.

Detailed investigation of a molecule involved in an inherited type of deafness reveals a fresh facet to the mammalian auditory system — a hitherto unknown way for synapses to put calcium in a bind.

That neutrons can be transmuted to protons, electrons and antineutrinos through the process of beta decay is old hat. That photons sometimes also get in on the act was suspected, but until now never confirmed.

The intricate process of ageing involves numerous physiological pathways, together with genetic and environmental factors. Insight into this complex biology could come from studying a disorder that accelerates ageing.

The PCP theorem encapsulates the idea that randomization allows the immediate verification of any mathematical proof. A simple route to this striking result was proposed earlier this year.

Crystal structures show that botulinum toxins bind simultaneously to two sites on neurons. This dual interaction allows them to use a Trojan-horse strategy to enter nerve terminals, with deadly effect.

Should males and females be kept together to avoid triggering virgin birth in these endangered reptiles?

One of two papers showing that inhibition of Dll4-mediated Notch signalling inhibits tumour growth by deregulation of tumour angiogenesis.

Characterization of a new human XPF mutation (XFE) that leads to profound DNA intrastrand crosslink sensitivity and progeroid symptoms is reported, indicating that the accumulation of DNA damage induces a metabolic response aimed at extending life span rather than maintaining growth.

The bright, nearby γ-ray burst (GRB) 060614 does not fit in either of the two duration classes. Its ∼102-s duration groups it with long-duration GRBs, whereas its temporal lag and peak luminosity fall entirely within the short GRB subclass. This opens the door on a new GRB classification scheme that straddles both long and short bursts.

GRB 060505 and GRB 060614 were not accompanied by supernova emission down to limits hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425, and fainter than any type Ic supernova ever observed.

Deep optical observations of GRB 060614 show no emerging supernova with absolute magnitude brighter than M_V = − 13.7. Any supernova associated with GRB 060614 was therefore at least 100 times fainter, at optical wavelengths, than the other supernovae associated with GRBs.

Optical observations of γ-ray burst (GRB) 060614 (duration ∼100s) rule out the presence of an associated supernova. This would seem to require a new explosive process: either a massive 'collapsar' that powers a GRB without any associated supernova, or a new type of engine, as long-lived as the collapsar but without a massive star.

The observation of the radiative decay mode of free neutrons, with measurements that agree with theoretical predictions may provide opportunities for more detailed investigations of the weak interaction processes involved neutron beta decay.

Monitoring of the flow of an ice sheet in Antarctica finds that the surface velocity oscillates by as much as 20 per cent every two weeks: the spring-to-neap tidal cycle seems to be the cause. Although the mechanism through which these tides couple to ice flow has yet to be elucidated, these observations caution against the use of velocity measurements over limited periods to infer long-term changes in flow rate.

Study of nerve cells in a bird's auditory system shows that those where spikes initiate closer to the cell body (or soma) are tuned to sounds with lower frequencies. Computer modelling suggests that spike initiation sites may also be key to coincidence detection by other neurons.

The structure of the influenza virus A nucleoprotein is visualized, revealing connected head and body regions with a groove in between for the viral RNA to sit.

One of two papers showing that inhibition of Dll4-mediated Notch signalling inhibits tumour growth by deregulation of tumour angiogenesis.

One of two papers that describe how botulinum toxins produced by Clostridium botulinum are potent inhibitors of neurotransmitter release by elucidating the crystal structure of botulinum toxin B bound to its receptor.

One of two papers that describe how botulinum toxins produced by Clostridium botulinum are potent inhibitors of neurotransmitter release by elucidating the crystal structure of botulinum toxin B bound to its receptor.

So long, and thanks for all the sausages.

Competition and cooperation in meerkat reproduction.