Volume 466 Issue 7304, 15 July 2010

The parlous state of the US icebreaker fleet could soon put a freeze on the country's polar research.

In today's tough climate, UK science must produce evidence to affirm its worth to the nation.

The week in science.

Researchers claim outbreaks of unknown haemorrhagic illness are no threat to humans.

Researchers challenge view of Cheonan sinking.

Study shows more US professors go into business as consultants than as inventors.

Some ecosystems bounced back after the 1979 Ixtoc I oil spill, but research quickly withered.

Scientists accuse officials of neglect as chemicals discolour stored relics.

Intellectual-property rules push researchers away.

Researchers call for effective monitoring and management of water resources.

A new class of materials is poised to take condensed-matter physics by storm. Geoff Brumfiel looks at what is making topological insulators all the rage.

An imminent swarm of tiny quakes beneath western North America could help seismologists prepare for a big one — but only if they can learn to interpret the tremors, finds Naomi Lubick.

The economic crisis is a setback to the European Research Area, warns Colin Macilwain — and the research community is ill-placed to respond.

The US government must make the Department of Defense a key customer for energy technologies and make greenhouse-gas reductions a public good, say John Alic, Daniel Sarewitz, Charles Weiss and William Bonvillian.

Samir Okasha is intrigued by a proposed universal law of biology: that complexity inevitably increases in the absence of other evolutionary forces.

The inventor and composer, whose group at the Massachusetts Institute of Technology's Media Lab developed the technology behind Guitar Hero, has electronically customized instruments for musicians from Prince to Yo-Yo Ma. As Machover prepares for the world premiere of his robotic opera Death and the Powers in Monaco in September, he explains how his interactive performance techniques might lead to personalized therapies.

The Universe is expanding. And the expansion seems to be speeding up. To account for that acceleration, a mysterious factor, 'dark energy', is often invoked. A contrary opinion — that this factor isn't at all mysterious — is here given voice, along with counter-arguments against that view.

Nature reserves and protected areas enjoy sacred status in conservation — which translates into a 'do not touch' attitude. But selling off some of the less worthy of them would pay conservation dividends.

According to theory, electrons on the surface of a topological insulator are not allowed to make U-turns. This notion, and some of its main consequences, has now been tested experimentally.

Time-resolved electron microscopy can capture structural changes in active macromolecular complexes, but detailed imaging is essential. The dynamics of one step in protein synthesis has been deduced from two million images.

Plate reconstructions show that ancient eruptions of diamond-bearing rocks occurred consistently above a ring-like region of plume-generation zones deep in Earth's mantle. Do such zones remain stationary?

During protein synthesis within the ribosome, transfer RNAs (tRNAs) move sequentially through different sites as their attached amino acids are transferred onto the growing protein chain. Large conformational movements accompany this process. Here, a staggering 1.9 million electron cryomicroscopy images of the ribosome have been processed to visualize these changes. The results reveal that the ribosome functions as a Brownian machine that couples spontaneous changes driven by thermal energy to directed movement.

The microbial content of the human gut has been the focus of much research interest recently. Now another layer of complexity has been added: the viral content of the gut. Virus-like particles were isolated from faecal samples from four sets of identical twins and their mothers, at three time points over a one-year period. The viromes (metagenomes) of these particles were then sequenced. The results show that there is high interpersonal variation in viromes, but that intrapersonal diversity was very low over this time period.

Circumstellar disks are an essential ingredient of the formation of low-mass stars, but it is unclear whether they are also required for the formation of stars more massive than about 10 solar masses. Clear observational evidence is needed, for example the detection of dusty disks around massive young stellar objects. Here, near-infrared interferometric observations are reported that spatially resolve the distribution of hot material around a high-mass young stellar object.

Topological surface states are a class of electronic states that might be of interest in quantum computing or spintronic applications. They are predicted to be robust against imperfections, but so far there has been no evidence that these states do transmit through naturally occurring surface defects. Here, scanning tunnelling microscopy has been used to show that topological surface states of antimony can be transmitted through naturally occurring barriers that block non-topological surface states of common metals.

In the high-transition-temperature superconductors, the pseudogap phase becomes predominant when the density of doped holes is reduced. In this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here, images of the intra-unit-cell states in underdoped Bi₂Sr₂CaCu₂O_{8 + δ} are studied, revealing electronic nematicity of the states close to the pseudogap energy.

Diamonds are formed under high pressure more than 150 kilometres deep in the Earth's mantle, and are brought to the surface mainly by volcanic rocks called kimberlites. Here, plate reconstructions and tomographic images have been used to show that the edges of the largest heterogeneities in the deepest mantle, stable for at least 200 million years and possibly for 540 million years, seem to have controlled the eruption of most Phanerozoic kimberlites. This has implications for future exploration for kimberlites.

Deep seismic tremor in subduction zones has been suggested to repeat at a regular interval, migrate at various velocities and be modulated by tidal stress. Here, evidence is presented that a time-invariant interface property — possibly the ratio of brittle to ductile areas — controls tremor behaviour in the Nankai subduction zone, Japan. Where tremor duration is short, tremor is more strongly affected by tidal stress and migration is inhibited. Where tremor lasts longer, diffusive migration occurs with a constant diffusivity.

The fossil record of primates is sparse, and many gaps remain in our knowledge. One gap relates to the divergence within the catarrhines — the ancestors of hominoids (apes and humans) and Old World monkeys. The discovery of a previously unknown catarrhine in Saudi Arabia, dated to 29–28 million years ago, helps to fill in some details. This specimen shows very few catarrhine specializations, suggesting that the divergence between Old World monkeys and hominoids must have occurred after this date.

Removing the protected status from poorly performing conservation areas, selling the land and using the money better elsewhere is controversial, but has a simplistic appeal. Here, it is shown that such degazetting can reap significant conservation benefits, even for the well-designed Australian network of protected areas, and even when there is a significant economic cost to transferring protected status to a new area.

The autistic spectrum disorders (ASDs) are highly heritable, yet the underlying genetic determinants remain largely unknown. Here, a genome-wide analysis of rare copy number variants (CNVs) has been carried out, revealing that ASD sufferers carry a higher load of rare, genic CNVs than do controls. Many of these CNVs are de novo and inherited. The results implicate several novel genes in ASDs, and point to the importance of cellular proliferation, projection and motility, as well as specific signalling pathways, in these disorders.

The primary visual cortex (V1) is crucial for vision, yet people with V1 injuries might still point to or avoid visual stimuli, despite having no conscious perception of them. It has been thought that this 'blindsight' relies on visual pathways that bypass the usual route from lateral geniculate nucleus (LGN) to V1. But it is shown here — using a combination of permanent and reversible lesions, behavioural testing and functional magnetic resonance imaging (fMRI) mapping — that a critical link in the alternative pathway is in fact the LGN.

During vertebrate development, the dorsal–ventral and anterior–posterior (A–P) body axes are determined first, after which left–right (L–R) asymmetry is established. But the molecular mechanism by which L–R symmetry is broken in reference to the other two axes is poorly understood. Here it is shown that two mouse genes, Vang1 and Vang2, which belong to the planar cell polarity family, are required to interpret the A–P patterning information and link it to L–R asymmetry.

It is shown here that the methylation of histone proteins regulates lifespan in Caenorhabditis elegans. Deficiencies in members of the ASH-2 complex, which trimethylates histone H3 at lysine 4 (H3K4), extend worm lifespan. Meanwhile, the H3K4 demethylase RBR-2 is required for normal lifespan. These findings are consistent with the idea that an excess of H3K4 trimethylation reduces longevity. The extension of lifespan caused by ASH-2 deficiency requires an intact adult germline and the continuous production of mature eggs.

Nucleosomes are composed of around 147 bases of DNA wrapped around an octamer of histone proteins. Here, a genome-wide analysis of nucleosome positioning in Arabidopsis thaliana has been combined with profiles of DNA methylation at single base resolution, revealing 10-base periodicities in the DNA methylation status of nucleosome-bound DNA. The results indicate that nucleosome positioning influences the pattern of DNA methylation throughout the genome.

Large-conductance Ca²⁺-gated K⁺ (BK) channels are essential for many biological processes, such as smooth muscle contraction and neurotransmitter release. Here, the X-ray crystal structure is presented of the entire cytoplasmic region of the human BK channel in a Ca²⁺-free state. Moreover, a voltage-gated K⁺ channel pore of known structure is 'docked' onto the gating ring to generate a structural model for the full BK channel.

Michael Ehlers will become the chief scientific officer for neuroscience research at drug firm Pfizer in August. He tells Nature why he decided to trade in his post in academia to explore a career in industry.

Job openings at pharmaceutical, chemical and engineering firms.

Economic woes force withdrawal of postdoc and PhD places.

Report suggests how European scientists can reduce gender inequities.

With traditional taboos receding, and the biotechnology and pharmaceutical sectors in flux, some researchers are moving from industry back to academia. Quirin Schiermeier looks at the trade-offs.

Proof positive.

HIV keeps the immune system in a hyperactive state, gradually leading to its ruin, reports Emma Marris.

Researchers hope to unlock the secrets of the select few who rein in, or even resist, HIV infection, says Bijal Trivedi.

Studies comparing HIV infection and its simian counterpart in different monkey species are filling gaps in knowledge, explains Bijal Trivedi.

Sarah DeWeerdt describes the intricate relationship between HIV and the host immune system, each influencing the other's next moves.

Recent successes are reinvigorating research into a vaccine for HIV, reports Cassandra Willyard.

No single strategy alone is likely to thwart HIV's spread. Researchers are turning to 'prevention packages' of two or more approaches, Cassandra Willyard reports.

There is a formidable arsenal of drugs available to treat HIV. Virginia Hughes finds that, for the first time in years, there is also renewed hope of a cure.

For many people in the developed world HIV is no longer the death sentence it once was. Paroma Basu explores the consequences of complacency.

There is more to combating HIV in the developing world than providing affordable drugs. T. V. Padma looks at the innovative new strategies being employed.

Co-infection with HIV and tuberculosis is a potent combination. Amy Maxmen investigates the impact of this deadly duo.

A Cambodian group has developed a pioneering community-based approach to HIV and TB care and research. Amy Maxmen describes how this powerful model is being expanded to other war-torn countries.

Specialization has its place, but truly innovative advances in HIV research usually come from interdisciplinary efforts, reports Unmesh Kher.

The miraculous drugs that keep so many HIV-positive individuals alive have blunted the urgency with which people talk about the AIDS epidemic. Even so, there is a renaissance afoot in HIV/AIDS research, with renewed focus on a cure, more powerful drugs and innovative approaches to prevention.