Volume 485 Issue 7400, 31 May 2012

The eradication of polio is within reach, but it is too early for self-congratulation.

The two-location solution for siting the Square Kilometre Array should not surprise us.

The commercial dream of trawling space for valuable minerals could bring enormous benefits to a wide range of sciences, argues Martin Elvis.

The week in science: Private spacecraft docks with International Space Station; changes to Brazil’s deforestation laws; and a US petition urges for open access to research.

Based in both Australia and South Africa, the Square Kilometre Array will face technical and financial challenges.

As hydraulic fracturing unlocks new gas reserves, researchers struggle to understand its health implications.

Critics question benefits of broader E. coli screening.

Political debate leaves German surveillance law in limbo.

Armed extremists are targeting nuclear and nanotechnology workers.

As the global eradication effort ramps up, funding shortfalls threaten the programme’s gains in Africa and Asia.

ORCID scheme will give researchers unique identifiers to improve tracking of publications.

Conservationists are taking heroic measures to restore the fertility of a three-footed Sumatran rhino. But some ask whether this is the right way to save an endangered species.

Once thought to be passive sentinels, microglia now seem to be crucial for pruning back neurons during development.

Establish a global agency to build a sustainable market for this precious commodity, say William J. Nuttall, Richard H. Clarke and Bartek A. Glowacki.

China's discomfort over discussing sex, and especially homosexuality, is a major problem when it comes to HIV, says a consortium of researchers in China.

On its 50th anniversary, an exposé of pesticide overuse still stands as a beacon of reason, finds Rob Dunn.

Nigel Shadbolt weighs up a timely look at a key digital challenge — interoperability.

Alison Abbott delves into the legacy of a remarkable Italian scientist–spy and avid collector.

DNA is the material of choice for making custom-designed, nanoscale shapes and patterns through self-assembly. A new technique revisits old ideas to enable the rapid prototyping of more than 100 such DNA shapes. See Letter p.623

When the heart is injured, the muscle does not regenerate and scars are produced. This process can be attenuated in the hearts of live mice by forcing scar-forming cells to become muscle cells. See Articles p.593 & p.599

An analysis of microscopic and spectroscopic features of sediments deposited in a South African cave one million years ago suggests that human ancestors were using fire much earlier than had been thought.

Quasiparticles known as repulsive polarons are predicted to occur when 'impurity' fermionic particles interact repulsively with a fermionic environment. They have now been detected in two widely differing systems. See Letters p.615 & p.619

Recognition of aberrant cell death is a crucial function of the immune system. It seems that one way in which immune cells identify damage is by sensing actin, an abundant intracellular protein.

Elucidation of a signalling pathway that promotes tumour-cell survival during metabolic stress reveals that a protein called AMPK may both hinder and enhance cancer progression. See Letter p.661

Previous work has shown that a combination of three transcription factors can directly reprogram cardiac fibroblasts into cardiomyocyte-like cell in vitro; now, the same authors demonstrate in vivo reprogramming of cardiac fibroblasts into induced cardiomyocytes.

A combination of four transcription factors, GATA4, HAND2, MEF2C and TBX5, can reprogram fibroblasts into cardiac-like myocytes in vitro and in vivo; expression of these factors ameliorated cardiac function in mice that had suffered myocardial infarction.

In the Drosophila testis, IGF-II messenger RNA binding protein (Imp) is shown to promote stem-cell niche maintenance by stabilizing unpaired (upd) RNA; Imp levels decrease in the hub cells of older males, owing to regulation by the microRNA let-7.

Calibration of an astronomical spectrograph using a laser frequency comb yields a short-term Doppler shift repeatability of 2.5 cm s⁻¹, which is sufficient to calculate the orbit of an extrasolar planet.

Radio-frequency spectroscopy is used to identify a long-lived, metastable quasiparticle in a lithium–potassium Fermi mixture with strongly repulsive interactions.

Investigations of a two-dimensional spin-imbalanced Fermi gas reveal the existence of the Fermi polaron for attractive and repulsive interactions, and the transition from the attractive polaron to a molecule.

Complex, self-assembling, two-dimensional nanostructures can be built of single-stranded DNA tiles by a method that allows individual control of more than one thousand distinct components.

Hafnium isotope ratios obtained from zircons in southern West Greenland suggest that Earth’s ancient crustal growth changed around 3.2 Gyr ago to a modern geodynamic regime involving juvenile crust generation by plate tectonic processes.

Molecular phylogenies demonstrate a link between colour polymorphism and accelerated speciation in bird families.

This paper reports the genome sequence of domesticated tomato, a major crop plant, and a draft sequence for its closest wild relative; comparative genomics reveal very little divergence between the two genomes but some important differences with the potato genome, another important food crop in the genus Solanum.

Comparison of Prdm9^−/− and wild-type mice reveals a role for the PRDM9 protein in directing the recombination machinery away from important genomic regions.

Neurotransmitter release and activity are modulated in the striatum of mice to demonstrate that the balance of activity within the two antagonistic, inhibitory pathways co-mingled in this nucleus regulates excitatory innervation of the basal ganglia during development.

It is shown that the formation of amyloid-β oligomers, one of the histopathological signatures of Alzheimer’s disease, can be triggered by small quantities of a specifically truncated and post-translationally modified version of amyloid-β.

The binding of angiopoietin-like proteins to immune-inhibitory receptors maintains ‘stemness’ of haematopoietic stem cells and supports leukaemia development.

A mechanism is suggested that helps tumour cells survive energy stress conditions during early stages of tumorigenesis.

Connecticut's investment initiatives are boosting research prospects, despite the region's languishing pharmaceutical sector.

Actress makes the shift from television to neuroscience and then back again.

Quick decisions for a difficult future.

For women worldwide, breast cancer is the most common cancer diagnosed and has the highest death toll. With improvements in screening and treatments over the past 50 years, more women are living longer, but the numbers reveal some tough challenges. By Amy Maxmen.

Researchers are delving into triple-negative breast cancer, uncovering potential drug targets for this difficult-to-treat disease.

Growing evidence shows that pregnant patients can beat breast cancer without endangering the unborn child.

If detected early, most cases of breast cancer seem to be curable. But the tumour's deadly offspring could be sleeping in the body.

The system for clinical trials must be redesigned if there is to be a decline in breast cancer metastasis, argues Patricia S. Steeg.

Researchers are turning to breast density to help predict cancer risk.

Physical activity has numerous proven benefits, and its long-contested ability to keep cancer at bay is now being put to the test.

The search for the genetic determinants of breast cancer risk is focusing on ever smaller effects, requiring larger groups of subjects.

Specific research and treatment of breast cancer in men has been neglected and deserves greater attention, says Valerie Speirs.

Each year, 1.3 million women — and some 13,000 men — are diagnosed with breast cancer. The past few decades have seen huge advances in treatment, but about one-quarter of those diagnosed will die from the disease. Complicating matters, breast cancers are remarkably diverse, and tumour cells seem to hide in 'cured' individuals. The difficult challenges are only just starting.