Volume 495 Issue 7440, 14 March 2013

Although debate over scientific definitions is important, it risks obscuring the real issues.

Educating patients is key, but the US National Cancer Institute must keep spending in check.

Self-criticism is a virtue seldom possessed by men, and never by the leaders of Western science, says Colin Macilwain.

The week in science: Life found in Antarctica’s largest subglacial lake; Higgs still a standard boson; and trade protections agreed for endangered sharks.

Virus might have many animal reservoirs.

Standard control sequences aim to make genetic engineering more predictable.

Herschel space observatory nears its end after unravelling star formation and tracking dust from supernovae.

Graphene-like form of silicon proves hard to handle.

Mineral proves to be remarkably clean topological insulator.

Questions raised over protection levels for marine regions.

After years of delays and cost overruns, an international collaboration is finally inaugurating the world's highest-altitude radio telescope.

Massive open online courses are transforming higher education — and providing fodder for scientific research.

Fifty years after finding that these cosmic beacons lie far away, astronomers need to think harder about how they radiate so much energy, says Robert Antonucci.

It is a mistake to dismiss the people and projects coming out of lesser-known institutions, argues Keith Weaver — they have strengths too.

W. F. Bynum reassesses the work of John Snow, the Victorian 'cholera cartographer'.

Sandra Knapp relishes a biography of the ginkgo, an arboreal survivor that has outlasted the dinosaurs.

John Hawks enjoys a debunking of myths about our evolutionary fitness for the twenty-first century.

Ewen Callaway finds a showing of prehistoric artefacts aesthetically stunning, but a missed scientific opportunity.

The discovery that a new coronavirus associated with lethal respiratory infections binds to an evolutionarily conserved receptor on airway cells suggests that direct transmission from bats to humans may occur. See Letter p.251

The composition of Earth's core may be easier to resolve than previously thought. Laboratory experiments strengthen the hypothesis that oxygen and silicon are the prime candidates for the light elements present in the outer core.

Neurons use molecular motors to power the transport of cargoes along their axonal extensions. Fresh evidence challenges the view that cellular organelles called mitochondria are the main energy providers for this process.

A low-temperature synthesis has been developed to make single crystals of titanium dioxide that contain pores tens to hundreds of nanometres in size. This opens the way to cheap, highly efficient optoelectronic devices. See Letter p.215

Epigenetic changes to the genome can have heritable effects. An epigenome-wide study of wild plants identifies shared patterns of such modifications and their associations with genetic information. See Article p.193

Whether ovarian cancer originates in the ovary or the surrounding tissues is a focus of debate. Work in mice now shows that stem cells that replenish the ovarian surface epithelium can be the initiators of this cancer. See Letter p.241

A type of data-acquisition sequence in magnetic resonance imaging has been developed that rapidly and robustly quantifies properties of imaged tissue by elucidating a characteristic signal fingerprint. See Article p.187

A new approach to magnetic resonance, ‘magnetic resonance fingerprinting', is reported, which combines a data acquisition scheme with a pattern-recognition algorithm that looks for the ‘fingerprints’ of interest within the data.

A population epigenomic analysis of wild Arabidopsis thaliana accessions is presented, obtained by sequencing their whole genomes, methylomes and transcriptomes; thousands of DNA methylation variants are identified, some of which are associated with methylation quantitative trait loci.

Intracellular membrane potential changes are measured directly in mouse grid cells during navigation along linear tracks in virtual reality; the recordings reveal that slow ramps of depolarization are the sub-threshold signatures of firing fields, as in attractor network models of grid cells, whereas theta oscillations pace action potential timing.

An artificial Kerr medium has been engineered using superconducting circuits, enabling the observation of the characteristic collapse and revival of a coherent state; this behaviour could, for example, be used in single-photon generation and quantum logic operations.

The state of an itinerant microwave field can be coherently transferred into, stored in and retrieved from a mechanical oscillator with amplitudes at the single-quantum level, and the time to capture and retrieve the microwave state is shorter than the quantum state lifetime of the mechanical oscillator.

A new low-temperature synthetic method of growing semiconductor mesoporous single crystals of titanium dioxide is described; the resulting films have much higher conductivities and electron mobilities than nanocrystalline titanium dioxide.

Experimental evidence is presented which shows that water and hydrogen can coexist as two separate, immiscible phases in Earth’s mantle; such immiscibility might be responsible for the formation of enigmatic, extremely reducing domains inferred to exist in the mantle, and may provide a mechanism for the rapid oxidation of Earth’s upper mantle immediately following core formation.

The voltage-gated ion channel CALHM1 is vital to taste-stimuli-evoked ATP release from sweet-, bitter- and umami-sensing taste bud cells in mice, but does not seem relevant to the recognition of sour and salty tastes.

Targeted deletion of the chemokine Cxcl12 in different bone marrow stromal cell populations shows that distinct niches exist in the bone marrow for haematopoietic stem cells and lineage-committed progenitors.

A study of the physiological sources of the chemokine CXCL12 in mice shows that haematopoietic stem cells occupy a perivascular niche in the bone marrow whereas early lymphoid progenitors occupy a distinct endosteal niche.

The Polycomb repressive complex 1 (PRC1) is found to have important gene-dosage-dependent and sex-specific roles in primordial germ cell (PGC) development, including the maintenance of high levels of Oct4 and Nanog and ensuring the proper timing of meiosis through the suppression of retinoic acid signalling in female PGCs.

The hilum (a transitional region) of the mouse ovary is identified as a stem cell niche of the ovarian surface epithelium, and its cells are prone to malignant transformation after inactivation of common tumour suppressor genes, suggesting that they may be the origin of ovarian carcinoma.

A genetic study of natural variation in potato tuberization onset, an important phenotype for breeding potatoes adapted to different global day lengths, has revealed a role for StCDF1, a member of the DOF family of transcription factors.

Human coronavirus-EMC (hCoV-EMC) is a new coronavirus that has killed around half of the few humans infected so far; this study now identifies DPP4 as the receptor that this virus uses to infect cells.

Maintenance of normal levels of CP110 is essential to prevent over-duplication of centrosomes and genome instability; here, a deubiquitinating enzyme, USP33, is shown to stabilize CP110.

The X-ray crystal structures of SERCA1a, a Ca²⁺-ATPase from the sarcoplasmic reticulum, in the presence and absence of sarcolipin are reported; the structures indicate that sarcolipin stabilizes SERCA1a in an ‘open’ state that has not been well characterised previously, in which SERCA1a has not yet accepted calcium into its two high-affinity binding sites.

An X-ray crystal structure of sarcoplasmic reticulum Ca²⁺-ATPase (SERCA) in the presence of sarcolipin, a SERCA regulator, is presented; the structure shows that sarcolipin traps SERCA in a previously unidentified ‘open’ state in which its high-affinity Ca²⁺-binding sites are unoccupied, but accessible from the cytoplasm.

Scientists and engineers with an analytical bent are sought-after in natural-hazard risk assessment.

Australian government will take measures to attract international science talent.

US universities' top administrative posts got median increase above inflation for 2012.

After the plague.

Throughout history, gold has been prized around the world and eagerly sought. But where does it come from, and where does it all go? By Neil Savage.

High gold prices are making it worthwhile to look for gold in some unusual places.

The same property that gives stained glass windows their sublime beauty is being crafted in the latest nanophotonic technologies, says Anatoly V. Zayats.

Invisibly small particles of gold can be used to manipulate the properties of light.

Gold can speed up a multitude of chemical reactions — so why isn't it widely used in industry?

Microbial 'alchemy' could lead to new ways of detecting and producing the precious metal.

Prized for their versatility, optical properties and safety, gold nanoparticles are helping to image, diagnose and treat disease.

Prized since antiquity for its beauty and stability, gold is becoming a darling of the nanotechnology age. Gold nanoparticles can help pinpoint a tumour — and then carry drugs to it. It also holds promise for making extremely efficient solar cells, among other photonic applications. Nature Outlook: Goldreports on what's driving the twenty-first-century gold rush.