Reviews & Analysis

Soil biodiversity sustains human health and its loss can be mitigated by sustainable management.

Extreme drought or wet conditions have now been found to strongly influence the vegetative development of ecosystems. Semi-arid regions are most affected — raising concerns about their vulnerability to long-term drought in the future.

Immune cells called regulatory T cells accumulate in fat during ageing. The anti-inflammatory activity of these cells worsens age-associated defects in metabolism, in contrast to its effect in obesity. See Letter p.137

The protein IR25a is best known for its role as an odour receptor in flies, but an analysis reveals that it also acts to synchronize the circadian clock by sensing small temperature fluctuations. See Letter p.516

Thousands of extrasolar planets have been discovered, but none is a planet in its infancy. Observations have finally been made of a young planet growing in its birthplace — opening the way to many more such discoveries. See Letter p.342

A combination of two techniques — computed tomography and small-angle X-ray scattering — and serious computing power have enabled multi-scale, three-dimensional analysis of bone and tooth tissue. See Letters p.349 & p.353

The genome sequences of two members of the hemichordate group of marine invertebrates bring the evolution of their relatives, including vertebrates, into sharper focus. See Article p.459

By electrically stimulating the motor neurons of rats that have spinal-cord injury, in bursts that are attuned to the times at which the neurons receive voluntary motor commands, the animals' recovery can be improved.

A quantitative study of sleep patterns in three pre-industrial societies implies that our natural sleep duration is close to seven hours, and that sleep cycles are determined by environmental temperature as well as the light–dark cycle.

Analysis of the temperature ranges occupied by marine species finds that the vulnerability of ecological communities to global warming may depend more on organismal physiology than on the magnitude of change. See Article p.88

New evidence suggests that seismic waves from the Chicxulub meteorite impact doubled the eruption rate of lavas on the opposite side of the planet — a combination that led to the mass extinction at the end of the Cretaceous period.

A rocky planet close in size to Earth has been discovered in the cosmic vicinity of our Sun. The small size and proximity of the associated star bode well for studies of the planet's atmosphere. See Letter p.204

Two studies provide evidence that epithelial tumour cells do not need to transition to a mesenchymal-cell state to form metastases, but that this process does contribute to drug resistance. See Article p.472 & Letter p.525

Porous solids have many uses in the chemical industry, which has stimulated the development of several generations of such materials. A new generation has now arrived, with the report of permanently porous liquids. See Letter p.216

A sensitive cold-ion experiment probes sound at the level of phonons, the fundamental quantum units of vibration. It shows that phonons mix in such a way that they can be classified as 'bosonic' particles, like photons. See Letter p.74

A modelling study argues that comprehensive policy change could limit Australia's environmental pollution while maintaining a materials-intensive path to economic growth. But other paths are worth considering. See Article p.49

What could cause a water droplet to start bouncing on a surface? It seems that a combination of evaporation and a highly water-repellent surface induces droplet bouncing when ambient pressure is reduced. See Letter p.82

Some Staphylococcus aureus bacteria are thought to survive standard antibiotic treatment by 'hiding' in host cells. But an antibody–antibiotic conjugate has been developed that targets these bacteria in mouse models. See Article p.323