Reviews & Analysis

A long-standing problem in chemistry has been to find catalysts that allow molecules to distinguish between the two faces of reaction intermediates called carbocations. A way around the problem has been found. See Letter p.245

A remarkable example has been discovered of a plant tuning its immune defence against a pathogen. The tuning consists of maximal expression of the relevant genes at the time of day when attack is most likely. See Letter p.110

Conventional wisdom tells us that supermassive black holes are found exclusively in massive galaxies undergoing little star formation. But one such object has now been discovered in a star-forming dwarf galaxy. See Letter p.66

Fragile sites are genomic regions prone to deletions or other alterations during DNA replication. The reason for the susceptibility of these sites to damage may be simple: they contain few replication initiation sites. See Letter p.120

What role did the Arabian peninsula play in the expansion of our species out of Africa? An archaeological site in the United Arab Emirates provides tantalizing new evidence that supports an early human migration from Africa.

The aquatic plant Salvinia molesta is a widespread pest of waterways in the tropics and subtropics. A study of its control by a weevil in Australian billabongs sets a new standard in ecological time-series analysis. See Letter p.86

The rising trend in atmospheric concentrations of methane over the past 5,000 years has been attributed to human agency. A modelling study, of a power that has only now become possible, points to another cause. See Letter p.82

Two approaches have emerged for creating libraries of compounds for use in biological screening assays for drug discovery — fragment-based ligand design and diversity-oriented synthesis. Advocates of each approach discuss their favoured strategy.

For many – if not all – of us, cognitive enhancement is desirable, but agents that would truly improve memory are hard to find. Unexpectedly, the product of an imprinted gene emerges as a promising candidate. See Article p.491

The ability to store entangled photons in a solid-state memory, and to retrieve them while preserving the entanglement, is a required step on the way to practical quantum communication. This step has now been taken. See Letters p.508 & p.512

Oscillations in gene transcription that occur in response to biological daily clocks coordinate the physiological workings of living organisms. But turnover in cellular energy may be sufficient to make the clock tick. See Article p.498 & Letter p.554

Different groups of diving vertebrates vary greatly in size, with whales being by far the largest. A comparative investigation of the links between swimming speed, size and metabolism provides clues to the reasons.

With the spread of fast-food outlets and more sedentary lifestyles, the prevalence of diabetes in India is rising alarmingly. But the subpopulations at risk and the symptoms of the disease differ from those in the West.

The recently refurbished Hubble Space Telescope reveals a galaxy from a time when the Universe was just 500 million years old, providing insights into the first throes of galaxy formation and the reionization of the Universe. See Letter p.504