Volume 514 Issue 7521, 9 October 2014

The significance of expertise passed on by direct contact— tacit knowledge — is moot.

A mass beaching of walruses in Alaska is a sign of things to come.

Better collaboration is a laudable goal, but that alone will not be enough to fix the damage caused by Europe’s falling investment, says Amaya Moro-Martin.

The week in science: Ebola exported to US and Spain; Italy's health minister rejects controversial stem-cell trial; and tens of thousands of walruses crowd ashore in Alaska.

But proposals spur concern that development will pollute the nearly pristine site.

Political scorn on top of shrinking funds creates hostility between scientists and Tony Abbott’s government.

Metrologists meet to design the ultimate gravitational-constant experiment.

Ten-year brain-mapping effort will use monkeys to study human neural and mental disorders.

Physics prize recognizes potential of invention with power to reduce global electricity consumption.

Discoverers of brain’s navigation system get physiology Nobel.

Nobel prizewinners May-Britt Moser and Edvard Moser have spent a career together near the Arctic Circle exploring how our brains know where we are.

As the Large Hadron Collider prepares to come back to life after a two-year hiatus, physicists are gearing up to go beyond the standard model of particle physics.

Researchers are divided over what processes should be considered fundamental.

Robert Seder applauds the chronicle of a secret US wartime project to vanquish the disease.

Linda Geddes is moved by an insider's take on how doctors and geriatric-care systems are failing old people and the dying.

Studies of stencils and paintings from prehistoric caves in Indonesia date the art to at least 39,900 years ago — around the same age as the earliest cave art previously known, 13,000 kilometres away in western Europe. See Letter p.223

The nature of ultraluminous X-ray astronomical sources has long been unclear. The latest observations of these rare systems provide some crucial clues, but still leave theorists scratching their heads. See Letters p.198 & p.202

The spliceosome enzyme complex removes intron sequences from RNA transcripts to form messenger RNA. The crystal structure of a lasso-shaped RNA suggests a mechanism for this splicing process. See Article p.193

A measurement of the mass of the heftiest-known elementary particle, the top quark, which exists for less than a trillionth of a trillionth of a second, sheds light on the ultimate fate of our Universe, although ambiguities cloud its interpretation.

Analyses in mice and humans indicate that non-caloric artificial sweeteners may promote obesity-associated metabolic changes by changing the function of the bacteria that colonize the gut. See Article p.181

A newly constructed electron-energy monochromator for an atomic-resolution transmission electron microscope has resolved spectroscopic signatures of chemical-bond vibrations that are spatially highly localized. See Letter p.209

The adoption of a new form of tool use has been observed to spread along social-network pathways in a chimpanzee community. The finding offers the first direct evidence of cultural diffusion in these animals in the wild.

Non-caloric artificial sweeteners (NAS), widely used food additives considered to be safe and beneficial alternatives to sugars, are shown here to lead to the development of glucose intolerance through compositional and functional changes in the gut microbiota of mice, and the deleterious metabolic effects are transferred to germ-free mice by faecal transplant; NAS-induced dysbiosis and glucose intolerance are also demonstrated in healthy human subjects.

Caspase-4 and caspase-11 are shown to be the direct sensors for cytoplasmic lipopolysaccharide in humans and mice, respectively, mediating inflammatory cell death in intracellular bacterial infection.

This study determines the structure of a branched lariat RNA, providing insights into rearrangement of the intron between the two steps of RNA splicing.

Ground-based and satellite observations show that the black hole in the ultraluminous X-ray source P13 has a mass of less than 15 times that of the Sun and displays the properties that typically distinguish ultraluminous X-ray sources from other stellar-mass black holes.

X-ray pulsations with an average period of 1.37 seconds have been detected from a known ultraluminous X-ray source hitherto thought to be a black hole; the pulsations instead unequivocally identify the source as an accreting magnetized neutron star ten times brighter than any previously known.

The magnetoresistance effect in WTe₂, a layered semimetal, is extremely large: the electrical resistance can be changed by more than 13 million per cent at very high magnetic fields and low temperatures.

Recent advances in electron microscopy are shown to allow vibrational spectroscopy at high spatial resolution in a scanning transmission electron microscope, and also to enable the direct detection of hydrogen.

A global, observation-based assessment of whole-ecosystem carbon turnover times shows that the overall mean global carbon turnover time is about 23 years and that locally its spatial variability depends on precipitation at least as strongly as on temperature.

Investigation of the chemical nature and sources of particulate matter at urban locations in four Chinese cities during a severe haze pollution event finds that the event was driven to a large extent by secondary aerosol formation.

Cave art from the island of Sulawesi in Indonesia, consisting of human hand stencils and animal paintings, is at least 40,000 years old, raising the question of why rock art traditions appeared at more or less the same time at opposite ends of the Late Pleistocene human world.

Inappropriate activation of the tumour-suppressor protein p53 during development can promote phenotypes similar to those of CHARGE syndrome, suggesting that p53 activation not only has a beneficial function in suppressing cancer but also a deleterious function in promoting developmental syndromes.

Using biochemical and genetic approaches, a protein-competition-based mechanism that controls the balance between stem cell self-renewal and differentiation of germline stem cells in the Drosophila melanogaster ovary has been uncovered.

In pre-clinical mouse models, the interleukin-22 pathway is identified as a novel target for therapeutic intervention in metabolic diseases.

In human β-thalassaemiaerythroblasts, HSP70 is sequestered in the cytoplasm by the excess of free α-globin chains and can no longer protect the master transcriptional factor of erythropoiesis GATA-1 from caspase-3 cleavage; transduction of a nuclear-targeted HSP70 or a caspase-3 uncleavable GATA-1 mutant restored maturation of erythropoiesis.

SUZ12, a component of the PRC2 complex, can also function as a tumour suppressor in certain tumours of the nervous system and melanomas.

The structure of mouse Dis3l2 bound to an oligoU substrate shows a funnel-like substrate-binding site with the RNA being fed into the active site along a path that is distinct from that seen in the related catalytic subunit of the exosome — 12 uracils of the oligoU-tailed RNA are recognized in a complex network of interactions, suggesting the basis for target specificity.

The POU homeodomain transcription factor Pit1 is required for pituitary development; here Pit1-occupied enhancers are shown to interact with the nuclear architecture components matrin-3 and Satb1, and this association is required for activation of Pit1-regulated enhancers and coding target genes.

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