Volume 510 Issue 7506, 26 June 2014

Measures of research impact are improving, but universities should be wary of their limits.

Environmentalists are divided over whether it is possible to have a ‘good’ Anthropocene.

As the education gap between city and countryside widens, young people face an invisible barrier to scientific research, says Qiang Wang.

The week in science: Chemist fined over burns death in lab; gravitational-waves team admits dust problems; and West African Ebola outbreak worsens.

Satellite will map sources and sinks of greenhouse gas in unprecedented detail.

Proposed innovation strategy is low on detail and commitments from governments.

Despite a chequered history, olaparib is finally before the US Food and Drug Administration.

Assessments by international biodiversity group aim to halt damage to world’s ecosystems.

State creates programme to boost neuroscience innovation.

Romance often sparks between colleagues, and scientists are no different. Nature profiles four super-couples who have combined love and the lab.

After decades of study, researchers still can't agree on whether nutritional supplements actually improve health.

Debates over oil-sands infrastructure obscure a broken policy process that overlooks broad climate, energy and environment issues, warn Wendy J. Palen and colleagues.

Fifty years ago, John Bell made metaphysics testable, but quantum scientists still dispute the implications. Howard Wiseman proposes a way forward.

Jonathan Adams takes the measure of the uses and misuses of scholarly impact.

Roger D. Launius is perplexed by a biography of Neil Armstrong that profiles the missions, not the man.

Biologist who won Nobel for solving antibody structure.

A means of verifying that nuclear warheads to be dismantled are genuine items has been proposed that potentially reveals no information to an inspector about the design of the weapons. Two experts explain the ins and outs of the method and its implications for arms-control policy. See Article p.497

A naturally occurring fungal compound has been found to restore the susceptibility of bacteria to a class of antibiotic that is currently considered to be our last defence against serious infections. See Article p.503

Published results of the gravitational constant, a measure of the strength of gravity, have failed to converge. An approach that uses cold atoms provides a new data point in the quest to determine this fundamental constant. See Letter p.518

Enzymes that attach amino acids to transfer RNAs during protein synthesis must recognize both substrates specifically. Crystal structures reveal a mechanism that explains the RNA specificity for one such system. See Article p.507

A method has been invented for determining nanoscale variations in the distribution of electric charge on surfaces. It has so far been used to examine specific inorganic materials, but could find widespread applications in imaging.

Many enzymes form 'assembly lines' containing a series of catalytic modules. Visualization of how the structure of a module shifts during catalysis provides a clearer idea of how such enzymes work. See Article p.512 & Letter p.560

N-heterocyclic carbenes are powerful tools in organic chemistry, with many commercially important applications; this overview describes their properties and potential uses.

Future rounds of nuclear arms control would ideally involve direct inspection of nuclear warheads using procedures that give inspectors high confidence about the authenticity of submitted nuclear items yet give no information about their design; this is now shown to be achievable using zero-knowledge protocols in neutron imaging of nuclear warheads.

The emergence of Gram-negative pathogens resistant to carbapenem antibiotics is a global health concern and carbapenem resistance often arises through acquisition of β-lactamase enzymes; this study identifies the natural fungal product aspergillomarasmine A as a metallo-β-lactamase inhibitor and a potential treatment to tackle carbapenem resistance.

X-ray crystal structures of a tRNA synthetase bound to wild-type and mutant alanine tRNAs reveal the structural basis for selectivity.

Polyketide synthases are multidomain enzymes that produce polyketides, which form the basis of many therapeutic agents; here, electron cryo-microscopy is used to establish the structure of a bacterial full-length module, and to elucidate the structural basis of both intramodule and intermodule substrate transfer.

Determination of the gravitational constant G using laser-cooled atoms and quantum interferometry, a technique that gives new insight into the systematic errors that have proved elusive in previous experiments, yields a value that has a relative uncertainty of 150 parts per million and which differs from the current recommended value by 1.5 combined standard deviations.

Single-walled carbon nanotubes of a single chirality can be produced with an abundance of more than 92 per cent when using tungsten-based bimetallic alloy nanocrystals as catalysts.

The isotopic composition of glacial sediment discharged into the ocean from south Greenland is used to identify a major reduction in the amount of that sediment derived from erosion of Greenland’s Precambrian bedrock, probably indicating the cessation of subglacial erosion and sediment transport during Marine Isotope Stage 11 as a result of the almost complete deglaciation of south Greenland.

Recordings from monkeys during motor learning suggest that durations of complex-spike (CS) responses to climbing-fibre inputs are meaningful signals correlated across the Purkinje-cell population during motor learning; longer climbing-fibre bursts lead to longer-duration CS responses, larger synaptic depression and stronger learning, thus forming a graded instruction.

Here human embryonic stem cell lines are derived by somatic cell nuclear transfer from cells of a newborn and from skin cells of an adult, a female with type 1 diabetes; the stem cells produced are pluripotent and can be differentiated into insulin-producing beta cells.

Medulloblastoma is a malignant childhood brain tumour presenting major clinical challenges; here, a comprehensive genome-wide DNA methylation data set from human and mouse tumours, coupled with analysis of histone modifications, RNA transcripts and genome sequencing, uncovers a wealth of alterations that provide insights into the epigenetic regulation of transcription and genome organization in medulloblastoma pathogenesis.

Metformin treatment of rats at physiologically relevant doses inhibits the redox shuttle enzyme mitochondrial glycerophosphate dehydrogenase.

Formation of an active cyclin D1–Cdk4 complex suppresses glucose metabolism independently of cell division.

Several proteins localized at membrane contact sites contain an SMP domain, which has been proposed to act as a lipid-binding module; here, the crystal structure of a fragment of the extended synaptotagmin 2 protein, including its SMP, is presented, and indicates that this protein may have a direct role in lipid transport.

Direct evidence for the role of BRCA1 in controlling homologous recombination at stalled replication forks has been obtained in mammalian cells using the bacterial Tus/Ter system.

Polyketide synthases (PKSs) are multidomain enzymes that produce polyketides, which form the basis of many therapeutic agents; here, electron cryo-microscopy is used to probe the structure of an intact module of a multi-enzyme PKS in different functional states.

Early-career researchers who help to organize conferences develop crucial skills that go beyond just booking speakers.

Christian researcher spreads message about climate change.

Opportunities for researchers open in California.

Government grant leads to hiring drive for international scientists.

Canadian professors bring attention to divide between administration and faculty members.

The voice of reason.

Stroke is a public-health problem that tends to affect poorer countries more and leaves richer countries with ballooning medical costs. Yet it is often preventable. By Zoë Corbyn.

Simply lowering blood pressure would reduce the risk of both stroke and age-related cognitive impairment, says Walter J. Koroshetz.

Mobile stroke units can save lives by treating people before any damage starts to take hold.

The key to stroke recovery is to coax the brain cells to heal without creating more damage in the process. A clever delivery system may just do the trick.

Interactive devices are helping people who have had a stroke to regain their motor function.

Strokes can shatter a person's identity and make it difficult to find the light. But there are ways to help patients cope.

'Covert' strokes are a leading cause of dementia — and their incidence will rise in step with that of vascular risk factors, says Antoine M. Hakim.

Stroke is the second most common cause of death worldwide, yet it can often be prevented. Each year, some 17 million people worldwide will have a stroke and almost 6 million of them will die. Research seeks to guide rehabilitation, to help maintain brain function after a stroke, and to develop treatments to repair the physical damage caused by the condition.