X-rays yield clues to the evolution of a yardstick supernova.
Transparency and quality control are essential in the highly uncertain business of assessing the impact of climate change on a regional scale.
It is time to abandon GDP as the overriding measure of social development and economic health.
Professor's arrest sends shock waves around the University of Alabama in Huntsville.
Some argue that tumour cells obtained directly from patients are the best way to study cancer genomics.
Next generation of machines could answer different research questions.
Atomic-clock experiment pins down accuracy of fundamental gravity measurement.
Experiments have revealed how single mutations can have huge effects that drive evolution. But small steps pave the way, finds Tanguy Chouard.
As hundreds of US astronomers draft their latest decadal wish list of new projects, Nature took a short-cut by convening a small survey around a dinner table. Eric Hand listens in.
Protesters saying "no to CO2" are just one roadblock facing carbon sequestration — a strategy that could help prevent dangerous climate change. Richard Van Noorden investigates.
Scientists and the media are trapped in a cosy relationship that benefits neither. They should challenge each other more, says Colin Macilwain.
Roger Bilham, one of the first seismologists to visit Haiti after last month's earthquake, calls for UN enforcement of resistant construction in cities with a history of violent tremors.
We need realism, not positivity, to learn lessons from past societal demises, urges Jared Diamond.
After obtaining a PhD in planetary physics, David Brin found that he could make a better living as a science-fiction novelist than a researcher. In the third in our series of five interviews with authors who each write science books for a different audience, Brin reveals that criticism — and a thick skin — are the keys to good creative writing.
Big and beautiful microfossils have been extracted from rocks that are more than 3 billion years old. They offer tantalizing hints about the antiquity of the eukaryote lineage of organisms that includes ourselves.
In some galaxies, matter falling onto a supermassive black hole is ejected in narrow jets moving at close to the speed of light. New observations provide insight into the workings of these cosmic accelerators.
When environmental temperatures rise, plants seek help from their core molecular mechanisms to adapt. The chromatin protein H2A.Z, which regulates gene expression, is one such rescue molecule.
Researchers have met the challenge of capturing transient states of the SUMO E1 activating enzyme. Their pictures show radically different crystal structures for two of the steps in this enzyme's activity.
A technique used primarily to study fundamental issues in quantum mechanics has now been shown to have promise as a powerful practical tool for making ultra-precise measurements.
The production of intestinal cells in a worm embryo is regulated by a network of transcription factors. Studies of these networks in mutant worms provide evidence for stochastic effects in gene expression.
Homozygous gene deletions in cancer cells occur over recessive cancer genes (where they can confer selective growth advantage) or over genes at fragile sites of the genome (where they are thought to reflect increased DNA breakage). Here, a large number of homozygous deletions in a collection of cancer cell lines are identified and analysed to derive structural signatures for the two different types of deletion. More deletions are found in inherently fragile regions, and fewer overlying recessive genes.
One way of discovering genes with key roles in cancer development is to identify genomic regions that are frequently altered in human cancers. Here, high-resolution analyses of somatic copy-number alterations (SCNAs) in numerous cancer specimens provide an overview of regions of focal SCNA that are altered at significant frequency across several cancer types. An oncogenic function is also found for the anti-apoptosis genes MCL1 and BCL2L1, which reside in amplified genome regions in many cancers.
The post-translational modification of cellular proteins by ubiquitin (Ub) and ubiquitin-like (Ubl) proteins — such as SUMO — regulates a broad array of cellular processes. E1 enzymes activate Ub and Ubl in two steps, by carboxy-terminal adenylation and thioester bond formation to a catalytic cysteine, but the structural basis for the intermediates remains unknown. Crystal structures for SUMO E1 in complex with SUMO adenylate and tetrahedral intermediate analogues are now reported and analysed.
Even genetically identical organisms in homogeneous environments vary, indicating that randomness in developmental processes such as gene expression may generate phenotypic diversity. Intestinal specification in the nematode Caenorhabditis elegans, in which wild-type cell fate is invariant and controlled by a small transcriptional network, is now studied. The results demonstrate that mutations in developmental networks can expose stochastic variability in gene expression, leading to phenotypic variation.
It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. However, the size of the emitting zone and the location of this region relative to the central supermassive black hole are poorly understood. Here, the coincidence of a γ-ray flare with a dramatic change of optical polarization angle is reported, providing evidence for co-spatiality of optical and γ-ray emission regions and indicating a highly ordered jet magnetic field.
Type Ia supernovae are thought to be associated with the thermonuclear explosions of white dwarf stars, but the nuclear runaway that leads to the explosion could occur through two different pathways with different X-ray signatures. The X-ray flux from six nearby elliptical galaxies and galaxy bulges is now observed to reveal that it is a factor of about 30–50 less than predicted by the accretion scenario, where a white dwarf accumulates material from a companion star.
One of the central predictions of general relativity is that a clock in a gravitational potential well runs more slowly than a similar clock outside the well. This effect, known as gravitational redshift, has been measured using clocks on a tower, an aircraft and a rocket, but here, laboratory experiments based on quantum interference of atoms are shown to produce a much more precise measurement.
For the first billion years or so of the Earth's history, there may have been whole-mantle convection, but after this period differentiation of the Earth's mantle has been controlled by solid-state convection. Many trace elements — known as 'incompatible elements' — preferentially partition into low-density melts and are concentrated into the crust, but half of these incompatible elements should be hidden in the Earth's interior. It is now suggested that a by-product of whole-mantle convection is deep and hot melting, resulting in the generation of dense liquids that sank into the lower mantle.
Claims that life existed on Earth in the early Archaean eon (3.2 billion years ago) are often controversial, as non-biological processes can produce life-like microstructures and chemical signatures that mimic those of the remains of living organisms. Now, however, the discovery of relatively large, carbonaceous spheroidal microstructures — interpreted as organic-walled microfossils — in early Archaean deposits adds further evidence that life existed, thrived and survived on Earth at a very early date.
Echolocation is usually associated with bats. Many echolocating bats produce signals in the larynx, but a few species produce tongue clicks. Here, studies show that in all bats that use larynx-generated clicks, the stylohyal bone is connected to the tympanic bone. Study of the stylohyal and tympanic bones of a primitive fossil bat indicates that this species may have been able to echolocate, despite previous evidence to the contrary, raising the question of when and how echolocation evolved in bats.
Until now, fully sequenced human genomes of the indigenous hunter-gatherer peoples of southern Africa have been limited to recently diverged populations. The complete genome sequences of an indigenous hunter-gatherer from the Kalahari Desert and of a Bantu from southern Africa are now presented. The extent of whole-genome and exome diversity is characterized; the observed genomic differences may help to pinpoint genetic adaptations to an agricultural lifestyle.
The brain's capacity to respond to instructive capacity underlies behavioural learning, but how instructive experience acts on the juvenile brain, a period in which learning is often enhanced, remains unknown. Here, two-photon in vivo imaging is used to study the brains of zebra finches as they learn to sing. The results indicate that behavioural learning results when instructive experience is able to rapidly stabilize and strengthen synapses on the sensorimotor neurons that control the learned behaviour.
The vertebrate body plan shows marked bilateral symmetry, although this can be disrupted in conditions such as scoliosis. Here, a mutation in Rere is found that leads to the formation of asymmetrical somites in mouse embryos; furthermore, Rere is shown to control retinoic acid signalling, which is required to maintain somite symmetry by interacting with Fgf8. The results provide insight into how bilateral symmetry is maintained.
Heterozygous mutations in the gene encoding CHD7, an ATP-dependent chromatin-remodelling protein, result in CHARGE syndrome — a disorder characterized by malformations of the craniofacial structures, peripheral nervous system, ears, eyes and heart. In humans and Xenopus, CHD7 is now shown to be essential for the formation of multipotent migratory neural crest and for activating the transcriptional circuitry of the neural crest; shedding light on the pathoembryology of CHARGE syndrome.
T lymphocytes, which are an integral part of most adaptive immune responses, recognize foreign antigens through the binding of antigenic peptide–major histocompatibility complex (pMHC) molecules on other cells to specific T-cell antigen receptors (TCRs). Using single-molecule microscopy and fluorescence resonance energy transfer, the kinetics of TCR–pMHC binding are now measured in situ, revealing accelerated kinetics and increased affinity when compared with solution measurements.
Ca2+ channels and calmodulin (CaM) are two prominent hubs of biological signalling networks, affecting functions such as cardiac excitability and gene transcription. The prevailing view has been that the ultrastrong affinity of channels for the Ca2+-free form of calmodulin (apoCaM) ensures their saturation with CaM and yields a form of concentration independence between Ca2+ channels and CaM. Here, however, significant exceptions to this autonomy are shown to exist.
As the techniques for imaging whole animals become more sophisticated, researchers are able to get a clearer picture of what is going on inside. Monya Baker looks at the options available.
The lot of women scientists would improve with more openness in policy and practice, argues Jan Bogg.
Instructing teenagers about science requires patience and a flair for presentation. Quirin Schiermeier reports on the prospects for scientists-turned-teachers in three countries.