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The US research community is responding vigorously to calls to help change the system of grant assessment at the National Institutes of Health. A radical transformation is urgently needed.
The flat-screen television boom has materials scientists scrambling to replace the valuable metal oxide that coats the screens. Andrea Chipman reports.
Particle accelerators that use plasma technology promise to shake up the fields of high-energy particle physics and cancer treatment. Challenges remain, but smaller, cheaper machines are within reach. Navroz Patel reports.
Above ground, plants compete for life-giving sunlight, but below the surface a more complex picture emerges. John Whitfield explores the role of mycorrhizae in plant ecology.
Funding woes plague US biomedical researchers. But calls for more funding ignore the structural problems that push universities to produce too many scientists, argues Brian C. Martinson.
Hanging around a star that has passed through its red-giant phase doesn't seem a likely place for a planet. But one planet apparently managed to avoid being engulfed by its bloated star — might others, too?
Adding methyl groups to DNA is a way of regulating some genes and genomic sequences. Structural analysis reveals that the enzyme complex that mediates this process shows unexpected sequence specificity.
Dynamic combinatorial chemistry is a deft way to identify the most stable forms in a complex mixture of interconverting compounds. Even more cunningly, it can also be used to sort related molecules by crystallization.
The vegetation of arid ecosystems displays scale-free, self-organized spatial patterns. Monitoring of such patterns could provide warning signals of the occurrence of sudden shifts towards desert conditions.
A molecule consisting of two electrons and two anti-electrons is similar to, but different from, the familiar hydrogen molecule H2. Its creation heralds a new chapter in the formation of matter–antimatter states.
The culture of academia needs to change if scientists are to bridge the gap between research and the development of drugs and vaccines for neglected diseases in the developing world, says Declan Butler.
Governments must help accelerate the development of drugs needed to treat infectious diseases in the developing world, say Bénédicte Callan and Iain Gillespie.
One billion people worldwide suffer from tropical diseases. Andrew L. Hopkins, Michael J. Witty and Solomon Nwaka explain how drug-discovery networks might be scaled up to address the lack of treatments cost-effectively.
Differential pricing could make global medicines affordable in developing countries. But drugs for diseases that have no market in the developed world will require additional subsidies, says Patricia M. Danzon.
Brazil urgently needs to improve infrastructure for generating pharmaceuticals to alleviate the plight of its poor and marginalized populations, say Carlos M. Morel et al.
Generation of the organizer tissue is induced on the dorsal side of the developing embryo by an asymmetry in Nodal signalling, which is only sufficiently high dorsally to induce organizer-specific gene expression. Now, through the identification of a microRNA (miR-15 and miR-16) that targets the Nodal receptor, microRNA is shown to have a role in this process.
The discovery of a planet orbiting the post-red-giant phase star V 391 Pegasi at a distance of about 1.7 astronomical units (AU) is reported. The maximum radius of the red giant phase was ∼0.7 AU, whereas the distance of the planet during main sequence phase was ∼1 AU. This demonstrates that planets with orbital distances < 2 AU can survive the red giant expansion.
Numerical simulation and modelling of the retreat and growth of ground ice on Mars demonstrates how the subsurface ice sheets could have evolved and ended up in the state we see them today, and also reveals that 40 major ice ages occurred on Mars over the past 5 million years
When intense positron bursts are implanted into a thin film of porous silica, di-positronium (Ps2) is created on the internal pore surfaces, providing experimental proof of the existence of the molecule. Using a more intense positron source, it may be possible to form a Bose–Einstein condensate of Psf2 molecules, which would be of significant fundamental interest and a milestone on the path to produce an annihilation gamma-ray laser.
Tropical sea surface temperatures during the Palaeozoic era were reconstructed from fossil shells using the 'carbonate clumped isotope' method, which, unlike the oxygen isotope method, does not require independent estimates of the isotopic composition of seawater. Estimates indicate that carbon dioxide concentrations and surface temperatures were closely coupled during the Palaeozoic era, supporting the view that variations in atmospheric carbon dioxide concentration led to significant variations in global temperature.
Large numbers of osmium alloy grains are analysed to quantify the distribution of ages at which melt was extracted from the Earth's mantle. It is found that the ages are not evenly distributed but cluster in distinct periods, around 1.2, 1.9 and 2.7 billion years, coincident with peaks in the ages of continental crust, lending strong support to pulsed models of continental growth via large-scale mantle melting events.
Attempts to place Palaeolithic events in climatic context are hampered by the difficulty of calibrating the radiocarbon calendar beyond around 21,000 radiocarbon years ago, and the absence of a 'master' calendar chronology for climate events. But this is circumvented by relating radiocarbon years to the paleoclimatic record through the excellent Cariaco Basin deep-sea record. In this way it is possible to relate the disappearance of Neanderthals in Europe to known climatic events.
It is shown that clusters of tree canopies within Kalahari landscape in southern Africa lack characteristic size, with the size distributions following power laws. Model results indicate that this apparent self-organized behaviour can be explained by positive feedbacks that operate in this water-limited ecosystem as a result of preferential environments formed within the vicinity of existing trees.
This paper describes and models the effect of grazing on vegetation patchiness in three arid Mediterranean ecosystems. The patch size distribution of the vegetation in these ecosystems follows a power law, which can be explained by invoking local positive interactions among plants. Deviations from power laws occur when grazing pressure is high, and may be a harbinger of imminent desertification.
A generalized trait-based model is derived to predict plant growth and hence the flux of carbon within and across plants. The model provides a theoretical basis for the merging of metabolic scaling theory with recent work on functional trait spectra, in turn helping to understand the integration of functional traits within plant phenotypes.
Use of a novel approach to generate mosaic animals shows that Down syndrome cell adhesion molecules (Dscam) diversity plays a crucial role in providing neurons in the Drosophila central nervous system with the ability to distinguish between self and non-self, which is essential to patterning neural circuits.
Mice that cannot sense glucose with their pro-opiomelanocortin (POMC neurons) develop glucose intolerance, demonstrating that glucose sensing in neurons plays an important role in responding to a systemic glucose load. It is also shown that in mice with obesity-induced type 2 diabetes, glucose-sensing by POMC neurons is defective.
A comprehensive structural analysis of the complete and unmodified Sup35 prion domain in two distinct infectious conformations is presented. A variety of techniques is used to provide structural details of these two prion conformations, one weakly and one strongly propagating strain. The data show that the fibril conformation of both strains share a common amyloid-like core, comprising the glutamine/asparagine rich first 40 residues.
In the weaker strain this stable structure is dramatically expanded to 70 amino acids.
The 'immortal strand' hypothesis has been proposed as a mechanism by which adult stem cells minimize accumulation of mutations. This is achieved by selectively retain chromosomes containing 'old' DNA, as shown by the analysis of the DNA strands that incorporated radioactive label or a nucleotide analogue such as bromodeoxyuridine. A new important contribution to this ongoing debate shows that 'the immortal strand' model does not apply to haematopoietic stem cells and BrdU label retention should not be viewed as a fundamental characteristic of stem cells.
Plant pathogens produce effector proteins that enhance virulence in susceptible plants, but trigger an immune response in resistant plants. This hypersensitive response is elicited through the interaction between the bacterial effector and the appropriate host resistance protein. This study describes the first crystal structure of a pathogen effector (AvrPto) bound to its cognate host protein (Pto).
A crystal structure of a complex between the DNA methyltransferase regulatory factor Dnmt3L and the catalytic domain of Dnmt3a leads to a model being proposed for the preferential methylation of DNA on maternally imprinted genes.
Tropical diseases affect more than one billion people, yet there are few effective treatments. And despite much research activity, scientific innovations with therapeutic potential are not making it out of the laboratory. The articles in this Outlook examine what can be done to stimulate the development of effective medicines and deliver them to the people who need them most.
