Volume 454 Issue 7204, 31 July 2008

Governments need to back an overhaul to get the electricity grid ready for renewable energy.

Although the Euroscience Open Forum is a meeting to be proud of, its organizers should aim even higher.

Move seen as shift from research to commerce and defence.

UK judge blocks access to high-school-level courses.

New types of solar cell that can be mass-produced cheaply, and integrated into building materials, are popular with venture capitalists and market analysts. But scientists are less gung ho, reports Declan Butler.

Antikythera Mechanism may have timetabled ancient Olympic Games.

Scribbles on the margins of science.

Far from being junk, these snippets of the genome exert wide-ranging influence.

X-ray reveals mystery portrait.

The director of Fermi National Accelerator Laboratory in Batavia, Illinois, talks to Eric Hand about the uncertain future of particle colliders in the United States.

Researchers trying to develop an HIV vaccine have endured two decades of setbacks. Erika Check Hayden meets a veteran still engaged in the fight — and a rookie willing to join in anyway.

Electricity grids must cope with rising demand and complexity in a changing world. Emma Marris explores the intricacies involved in controlling the power supply.

A field guide to the formation of Italy's Apennine mountains mixes the science behind the dinosaur extinction with accounts of travel and Italian history, explains Ted Nield.

Many nanotechnology devices will require components that consist of arrays of molecules positioned on surfaces with nanometre precision. One way to make these is to let the molecules organize themselves.

When a potentially dangerous cell can't be repaired, it must be either stopped or killed. Premature senescence of cancerous cells is one such 'stop' mechanism, in which immune mediators play an unexpected part.

While orbiting Saturn, the Cassini spacecraft has spotted lakes containing ethane on Titan, the planet's largest moon. Titan is so far the only planetary object other than Earth that is known to have liquid bodies on its surface.

Do you find it difficult to overcome an irrational fear? Blame it on the specific neural circuits hardwired in the brain that control fear recognition, and fear renewal even when fear has seemingly been overcome.

Multiferroic materials have complex domain structures that make precise interpretation of their behaviours difficult. The creation and study of a single-domain multiferroic crystal is thus an exciting development.

What do we humans have in common with flies? Quite a lot, at least at the cellular and molecular levels. Our intestine, for instance, is similar to that of the fly, not only in function but also in its development and maintenance.

There are no sequential snapshots of a transporter protein as it mediates the simultaneous passage of ions and solutes into a cell. Comparing different snapshots of structurally related transporters offers fascinating insights.

Acyl-homoserine lactone (AHL) quorum sensing allows population-dependent control of gene expression in numerous bacterial species. Many AHL quorum-sensing systems are known, all of which use fatty acid groups to provide AHL specificity. This paper reports the discovery that some bacteria make a non-fatty AHL by using enzymes related to the fatty AHL synthase pathway, thus greatly expanding the realm of signal possibilities.

Changes in the balance of activity of two distinct neuronal populations in the basolateral amygdala trigger transitions between states of high and low fear in mice. The two populations of neurons tend to participate in different anatomical circuits, suggesting that even within a single brain area, selective activation of specific neuronal circuits can trigger large changes in behavioral state.

Titan was once hypothesized to have global oceans of light hydrocarbons, but it has become clear that none exist. However there are features similar to terrestrial lakes and seas. This paper reports infrared spectroscopic data that strongly indicate that ethane, probably in liquid solution with methane, nitrogen, and other low-molecular-weight hydrocarbons, is contained within Titan's Ontario Lacus.

Two types of magnetic order appear in metals, 'itinerant-electron' magnetism and 'local-moment' magnetism. A class of strongly correlated electron materials bridges these two extremes, with itinerant-electron magnetism reigning at low temperature and local-moment magnetism at high temperature. It has been a long-standing goal to quantitatively describe the transition between these two. This paper reports a simple semi-quantitative solution to the latter problem that provides a new framework for interpreting the physics of heavy electron materials.

The Antikythera Mechanism, a box of intricate gearwork recovered in a shipwreck, is a startling insight into the engineering prowess of the Hellenic world. New interpretations of the mechanism reveal how it could be used to predict eclipses; that it was probably made in a colony of Corinth and that it had a dial recording the times of the ancient Olympiads.

The patterning of surfaces is often accomplished by either supramolecular self-assembly of molecules into surface networks, or the deposition of self-assembled monolayers (SAMs). Supramolecular assembly is attractive because it yields patterns that are exactly defined at the nanometre scale, whereas SAMs offer unprecedented flexibility for creating functionalized surfaces. Now the advantages of both methods have been harnessed by first creating self-assembled surface networks and then depositing SAMs into the network pores.

Experimental and geochemical observations show that silicate mineral inclusions in diamonds from Juina, Brazil, crystallized from primary and evolved carbonatite melts in the mantle transition zone and deep upper mantle. Such small-degree melts of subducted crust can be viewed as agents of chemical mass-transfer in the upper mantle and transition zone, leaving a chemical imprint of ocean crust that can possibly endure for billions of years.

Seafloor communities in the Palaeozoic Era differed markedly from the subsequent Mesozoic and Cenozoic eras. This is because in the Palaeozoic, seafloors were mostly based on carbonates, whereas succeeding ones were generally sandy.

Many advanced snakes use fangs to inject venom into their prey. The fangs may be either at the front or rear of the upper jaw, but biologists have been unable to agree whether these two arrangements are evolutionarily related. It is now shown that front fangs develop in the rear part of the jaw, and that the resemblances between front and rear fangs are so striking during their development that homology is probable.

This paper presents an example of a percolation threshold for infectious disease, namely the plague among great gerbils in Central Asia. The threshold arises from the spatial constraints on flea dispersal movements that carry plague from one family group of great gerbils to another. These movements are small compared to the vast contiguous areas of desert that have been colonized by the great gerbil. The result is a percolation system wherein plague is only able to percolate through the landscape if it is sufficiently 'filled' with family groups of hosts.

A new principle for control of organ size is discovered by using the mouse limb bud to study how signals signalling growth and expansion are terminated. A combination of mutations were identified that revealed an inhibitory loop whereby FGF signalling represses Gremlin1, these two factors being key positive signals in limb bud outgrowth. This inhibitory loop is triggered by a positive FGF/Shh loop, and this model differs from earlier published models.

Although fearful responses to stimuli associated with unpleasant consequences are quickly learned, they can also be unlearned. This unlearning process, called 'extinction', is thought to depend on plastic changes in the amygdala. A specific population of amygdala cells (intercalated neurons) that are responsible for this unlearning have been pinpointed. Selective destruction of this cell type with a toxin leads to a corresponding decrease in the extinction of learned fear memories.

It is detailed that adult mouse neural stem cells (NSCs) express higher endogenous levels of Sox2 and c-Myc than embryonic stem cells, and that exogenous Oct4 together with either Klf4or c-Myc are sufficient to generate iPS cells from NSCs. The number of reprogramming factors can be reduced when using somatic cells that endogenously express appropriate levels of complementing factors.

In adult Drosophila melanogaster, intestinal stem cells (ISCs) of the posterior intestine (hindgut) are confined to an anterior narrow segment, the hindgut proliferation zone (HPZ). Within the HPZ, self renewal of ISCs, as well as subsequent proliferation and differentiation of ISC descendants, are controlled by locally emanating Wingless (Wg, a Drosophila Wnt homologue) and Hh signals.

The vascular endothelial growth factor (VEGF) receptor subtype VEGFR-3 is only expressed on lymphatic endothelium in adults. However, VEGFR-3 is upregulated in the vasculature of tumours by Notch signalling. VEGFR-3 inhibition interferes with tumour angiogenesis and tumour growth, in particular in combination with inhibitors of the VEGFR-2, suggesting that it represents a novel anti-angiogenic target for cancer therapy.

Scientists who enter the world of political advocacy stand to gain perspective but could face a culture shock. Gene Russo reports.

Neuroanatomist takes multidisciplinary approach at Dartmouth.

NIH announces grants for investigating gender disparity.

New animal model, new challenges

What's love got to do with it?

Calibrating temperature and heavy-electron behaviour.