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The political commitment to helping the developing world is failing to deliver on its promises. The problem is made worse by the questionable evaluation of progress.
Since the Democrats took over the US House and Senate, ever more committees on climate change are holding hearings on a nearly daily basis. This month the leader of the House, Nancy Pelosi, formed yet another one, the Select Committee on Energy Independence and Global Warming, leaving even Washington energy analysts struggling to keep up with it all. Emma Marris charts the key players in terms of clout and greenness.
The buzz over invisibility cloaks is fun — while it lasts. But metamaterials are likely to transform optics through more mundane applications. Katharine Sanderson reports.
Many Iraqi academics have escaped death threats only to find that their qualifications are obsolete and immigration authorities are unsympathetic. Jim Giles hears their stories.
The US military is getting a lot of flak for the way it treats wounded soldiers returning from Iraq. Emma Marris reports on the advances in medical care that are helping to bring them home.
Some UK universities offer science degrees in complementary medicine. David Colquhoun argues that these are not science but anti-science, and asks who is to blame.
Between the nano- and micrometre scales, the collective behaviour of matter can give rise to startling emergent properties that hint at the nexus between biology and physics.
Chemists usually kick-start reactions with heat, light or electricity, but a far less common option is to use mechanical stress. It now seems that stress not only triggers reactions, but can also direct their course.
Two asteroids have been observed gradually spinning faster and faster, and the hot tip is that sunlight is the cause. If so, this could give us a handle on the dynamics and evolution of the asteroid belt in general.
Fragile chemical groups can be shielded from harsh reaction conditions by temporary protection. This approach is conventional wisdom for organic synthesis, but is it always the best solution?
Experiments with microorganisms can guide thinking about the big questions being tackled by evolutionary biologists — for instance, how predation and immigration might play a role in adaptive radiation.
The biosynthesis of vitamin B12 has fascinated generations of scientists, but part of the pathway was unknown. The missing enzymatic link has now been found, only to raise more mechanistic questions.
The stability of the chemical bonds in saturated hydrocarbons makes them generally unreactive. But the invention of processes in which carbon–hydrogen (C–H) bonds in hydrocarbons can be activated is allowing chemists to exploit organic compounds in previously unimaginable ways.
Transition metal catalysts containing gold present exciting new opportunities for chemical synthesis. Experimental and computational data is reviewed to present our current understanding of homogeneous gold catalysis, focusing on previously unexplored reactivity and its application to the development of new methodology.
Members of the hapalindole, fischerindole, welwitindolinone and ambiguine families were synthesized, each constructed without the use of a single protecting group. As a consequence, molecules that have previously required 20 or more steps to synthesize racemically in milligram amounts can now be procured as single enantiomers in significant quantities in 10 steps or less.
Seismic imaging is used to show that the isotropic and anisotropic structure of the Earth's mantle is rotated beneath the East Pacific Rise. The segmentation of the rise crest between transform faults correlates with the inferred distribution of mantle melt and indicates that this skewing of asthenospheric upwelling and transport governs segmentation of the East Pacific rise and variations in the intensity of ridge crest processes.
Clostridium difficile is the major cause of antibiotic-induced diarrhoea. It has been suggested that one of C. difficile's virulence factors, toxin B, is activated by a host protease upon cell entry. This study demonstrates that toxin cleavage is an autocatalytic process induced by host inositolphosphate.
Carefully designed 'mechanophores' can tame the 'brute force' approach needed for breaking chemical bonds in reactions. If incorporated into polymers and activated by mechanical forces, the mechanophores undergo rearrangement reactions to selectively form new molecules. The effect might result in mechanically responsive polymers that warn of impending structural failures, can slow damage or even self-repair.
The surface expression of the Great Meteor hotspot track in eastern North America is misaligned with respect to its location at 200 km depth, suggesting that asthenospheric flow may be deforming the lithospheric keel and exerting a driving force on this part of the North American plate.
This paper provides experimental evidence that the evolutionary processes that cause the 'bursts' of adaptive evolution are interfered with by predators. In reducing prey populations, predators slow the rate to which prey species diverge into new forms, stifling diversification. Deserted islands and the times of mass extinctions are circumstances where predators are rare; suggesting that their absence is why the bursts occur.
The ecological process of immigration into communities and the evolutionary process of diversification within communities are both important determinants of biological diversity. Use of model bacterial populations shows that the two processes are linked such that small differences in immigration history can greatly affect the extent of subsequent diversification.
Angiogenesis is involved in compensatory cardiac hypertrophy following pressure overload. However, the process also induces the accumulation of p53 which ultimately suppresses angiogenesis and thereby contributes to the transition from hypertrophy to heart failure.
The X-ray crystal structure of BluB is solved. Blub is an enzyme that uses molecular oxygen to cleave a flavin mononucleotide cofactor to form 5,6-dimethylbenzimidazole, which is incorporated into vitamin B12. The enzymatic destruction of one cofactor to synthesis another is quite unusual and this biochemical reaction represents the last unknown step in the biosynthesis of this vitamin.
How the Shine–Dalgarno (SD) sequence affects binding of the ribosome to mRNA is examined by measuring the force required to tear the ribosome from an mRNA with or without the SD sequence. This finds that the SD sequence stabilizes the ribosome–mRNA interaction before the first peptide bond is formed, but that once this occurs, the SD sequence can no longer stabilize it.
