Browse Articles

Hunter-gatherer populations in Africa preserve unique information about human history, but genetic sub-structures of these populations remain unclear. Using newly designed microarray and statistical methods, these authors analyse genetic compositions of southern African populations and reveal an ancient link between southern and eastern Africa.

The orientational order of nematic liquid crystals is a property that is controllable by external parameters such as electromagnetic fields and pressure gradients. Lavrentovich and co-workers demonstrate that thermal expansion can also induce orientational order that results in a flow of the liquid crystals.

Quantum phase transitions are most commonly found to occur at zero temperature. Cuevaset al.present numerical evidence confirming that a quantum phase transition can also occur at finite temperature, provided strong disorder is present.

The spontaneous adsorption of alkanethiols is widely utilized to fabricate functional surfaces but gives limited stability and regularity. Mattiuzziet al. report a method that uses preorganized platforms (rigid tetrapodant calix[4]arenes), which allows further surface functionalization and spatial control.

Microsporidia are widespread human parasites, but limited genome annotation has hampered efforts to understand their biology. Peyretailladeet al. use sequence motifs upstream of start codons to annotate or re-annotate microsporidian genomes and find new genes potentially involved in interactions with the host.

The mouse segmentation clock regulates the periodicity of somite formation. Okubo and colleagues investigate the mechanisms underlying the synchronization of the clock in embryonic chimaeras and find that the synchronization is regulated by the protein Lfng, which represses Notch signalling in neighbouring cells.

Prion proteins are implicated in a range of neurodegenerative diseases, which are, in part, due to a disruption of metal homeostasis. Wattet al.use selective antagonists to show that prion proteins mediate zinc uptake by interacting with GluA2-lacking, GluA1-containing AMPA receptors.

Copolymers prepared by controlled radical chain-growth polymerizations usually contain ill-defined monomer sequences. Here, successive feeds of donor and acceptor comonomers are used to control the primary structure of the synthesized copolymers with very high accuracy.

Studies on neural stem and progenitor cells have shown they may be useful in treating spinal cord injuries, but the results are variable. Kumamaruet al.transplant these cells in injured spinal cords of mice, and find that their therapeutic properties are dynamically altered depending on their environment.

Changes in bubble foam structure influence magma strength. Here, Bakeret al. measure bubble size and wall thickness of basaltic foams and find that basaltic magmas are most likely to fail immediately upon vesiculation, but a permeability increase within a few seconds may reduce the risk of explosive eruptions.

Axon regeneration inC. elegansis positively regulated by the JNK/MAP kinase pathway. Pastuhov and colleagues identify the endocannabinoid anandamide as a negative regulator of this pathway and show that anandamide inhibits axon regeneration in mature neurons after axotomy.

Light-emitting diodes are attractive sources of light used in an increasing range of applications. This study presents a novel europium-based phosphor that gives rise to a substantial reduction in the glare that often makes LEDs uncomfortable to the human eye.

Crystals containing atoms with widely disparate masses can exhibit unusual lattice dynamics. Using time-of-flight neutron scattering, Aczelet al. show that at high frequencies individual nitrogen atoms in uranium nitride behave as independent quantum harmonic oscillators.

It has been proposed that phylogenetic diversity can be used as a proxy to estimate functional diversity and to predict ecosystem functioning. Here, the rapid evolutionary response of marine bacteria is used to study the positive effects of evolutionary history and species diversity on ecosystem productivity.

Increased atmospheric input of nitrogen has shifted planktonic lake nutrient systems from natural nitrogen to human-induced phosphorus limitation. This study proposes that decades of increased atmospheric phosphorus in the Pyrenean lake district may have reverted the system from phosphorus back to nitrogen-limited.

Microdisk lasers are useful for compact wavelength-scale photonic devices and circuits, but their operation by electrical injection can hamper their optical properties. Kimet al. show that a graphene-contact electrode provides efficient electrical injection while minimising optical losses.

Computed tomography relies on scanning to measure an object from many angles, which fails for shot-to-shot changes and ultrafast phenomena. Matliset al. demonstrate an approach based on spectral multiplexing for single-shot tomographic imaging and use it to measure femtosecond plasma filaments.

Molecules in intense laser fields have enhanced multiple ionization rates, caused by the ionic core and laser fields acting on the part of the molecule in the up-field. Here, direct proof of this model is presented by studying the instantaneous effect of the field direction during double ionization in ArXe.

Humans, with their opposable thumbs, are not the only species with tool-related morphological adaptations. This study shows that tool use in New Caledonian crows is facilitated by a straight bill, enabling a firm grip on tools, and an extremely wide binocular field, affording excellent visual feedback.

Plasmonic nanoparticles are useful as optical sensors, but their spectral resolution is hindered by the linewidth of the plasmon resonance. Schmidtet al. find that coupling this resonance to a microcavity creates hybrid modes with enhanced sensing figure-of-merit and improved frequency resolution.