Review, News & Views, Perspectives, Hypotheses and Analyses in 2011

The chemical diversity of the oldest stars is greater than we thought. The discovery of an extremely iron-poor star with a 'normal' ratio of carbon to iron challenges our perception of early chemical enrichment. See Letter p.67

The brain's ability to generate new neurons declines with age. This reduction is mediated by increased levels of an inflammatory factor in the blood of ageing mice and is associated with deficits in learning and memory. See Letter p.90

Sticking plasters revolutionized the protection of minor wounds, but they're not ideal for fragile skin. A material that mimics the adhesive properties of certain beetles' feet might provide a solution.

Ecosystems acquire nitrogen from the atmosphere, but this source can't account for the large nitrogen capital of some systems. The finding that bedrock can also act as a nitrogen source may help solve the riddle. See Letter p.78

Nanoscale devices have now been made that mimic biological connections in the brain by responding to the relative timing of signals. This achievement might lead to the construction of artificial neural networks for computing applications.

Most galaxies harbour giant black holes; some are 'silent' whereas others produce copious amounts of radiation. The awakening of a silent monster has just been witnessed as it breaks apart and swallows a nearby star. See Letters p.421 & p.425

The idea that climate influences the onset of wars is enticing, but controversial. A study now finds a convincing correlation between global climate and civil conflict in countries affected by the El Niño/Southern Oscillation. See Letter p.438

Infection with a harmless bacterium makes the mosquitoes that transmit dengue virus resistant to viral infection. The resistant population can rapidly replace the natural, susceptible population. See Letters p.450 & p.454

With fossil-fuel supplies set to dwindle, the race is on to find ways of making fuels from renewable sources of biomass. Two experts discuss the broad strategies — biochemical and thermochemical — that have emerged as practical approaches.

The well-known boundaries of coffee stains are caused by the outward flow of particles suspended in the liquid. Experiments show that ellipsoidal particles can prevent the formation of such boundaries. See Letter p.308

Images of the sea floor in Pine Island Bay, West Antarctica, reveal impressive evidence that a massive ice-shelf break-up occurred before about 12,000 years ago, and point to a tidal influence on sea-floor features produced during deglaciation.

The protein Lgr5 has been valuable as the undisputed marker of intestinal and other stem cells. It emerges that Lgr5 and its relatives also have essential signalling roles of relevance to health and disease. See Article p.293

Tracing a common ancestry between languages becomes harder as the connection goes further back in time. A new test has revealed a surprisingly ancient relationship between a central Siberian and a North American language family.

Polarized emission has been detected from the largest Lyman-α gas cloud, known as blob 1. This result strongly suggests that such clouds are powered by a central source of ionizing radiation. See Letter p.304

A new type of ion-trap quantum technology has been developed that uses microwave radiation to perform computations. It will considerably simplify the practical implementation of large-scale quantum computers. See Letters p.181 & p.185

A three-year study provides insights into how the productivity of a semi-arid rangeland, containing grasses using different photosynthetic pathways, will change in a warmer world with more atmospheric carbon dioxide. See Letter p.202