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Physics and fossils

Many biologists have argued that most species become extinct when new ‘fitter’ competitors arrive on the scene. For example, some scientists believe the dinosaurs became extinct after a large meteorite hit the Earth 65 million years ago because warm-blooded mammals were better able to survive the long cold spells that followed. However, palaeontologists now argue that the collapse of the dinosaurs’ food sources had a bigger impact on the species than competition from mammals. The new computer model proves that mass extinctions are more dependent on an amplification effect between predators and their prey than any other factor.

Tectonic plate theory shaken on Mars

Mars is now a dry planet with most of its water either tied up in a deep permafrost or lost to outer space. However, images gathered by Mars Observer and earlier space craft such as the Viking orbiters, showed evidence of water channels, rivers, and water erosion. The most striking evidence consists of wide enormous flood plains in the Valles Marineris area.

Dykes are created when magma from deep inside the planet swells upwards and deforms the surface. The dykes on Mars are in the Tharis bulge, a region of the Martian surface that has a large volcanic plume underneath it. These dykes are 20 times bigger than anything seen on the Earth.

McKenzie and Nimmo calculated the amount of heat required to melt the Martian permafrost and modelled their results on a computer. They discovered the dykes produced enough heat to melt at least 7500 km³ of water – enough to have radically changed the surface temperature and humidity on the planet, and produced the water erosion seen in the region.

Are printed journals heading for extinction?

Scientific publishing is still a highly profitable business. According to Nature, the scientific side of the Reed-Elsevier publishing company made a profit of $378m on sales of $938m in 1997. However, the growth of electronic preprint or “eprint” servers, such as the physics server at Los Alamos, will soon radically change the way researchers publish their findings and libraries buy journals.

Publishers are experimenting with new business models such as making journals freely available over the Web and recouping costs through page charges to authors. This approach is being tried on the New Journal of Physics, a joint venture by the Institute of Physics (who publish PhysicsWeb) and the German Physical Society. Libraries, meanwhile, are encouraging academics and not-for- profit publishers to launch new journals in direct competition against high-priced journals from commercial publishers. And for journals with low circulations, one option being considered is to abandon printed versions altogether and rely on the Internet for distribution. However, the problem of future-proofing the archives of electronic-only journals against advances in hardware and software has still to be solved.

The Web is also leading to innovations behind the scenes at journals. For example, a software robot at the Journal of High Energy Physics, an electronic-only journal, scans papers submitted by email to select suitable referees – a task normally performed by the editors.

Quasicrystals clinch Wolf prize

Quasicrystals are materials that do not have a periodic lattice structure but still display subtle long-range order, such as “five-fold” symmetry, that is not possible in regular crystals. They appear to be built from two different structures assembled in a non-repeating array.

Five-fold symmetry was considered impossible in real materials until it was discovered by Shechtman at Johns Hopkins University in the US in the early 1980s. The discovery led to the exploration of an entirely new area of condensed matter physics.

Shechtman discovered quasicrystal structure in aluminum transition metal alloys. However, it was not until 1984 that separate teams working at the National Institute of Standards and Technology in Maryland, and at the University of Pennsylvania, were able to confirm Shechtman’s results. Potential applications of quasicrystalline materials include superconducting and ultrahard materials.

Shechtman will be presented with the prize, which is worth $100, 000, by the president of Israel in May.

Macroscopic spin moves

James Kikkawa and David Awschalom of the University of California, Santa Barbara have now shown that they can use electric fields to transport electrons through a distance of 0.1 mm in gallium arsenide without losing any of their quantum coherence (Nature 397 139). They cooled gallium arsenide substrates in a magneto-optical cryostat to 1.6 Kelvin. As pulses of laser light are passed over the sample they create ‘spin packets’ in the gallium arsenide. A step motor moves the sample inside the cryostat through the electric field, causing the spin packet to move through the sample. According to Kikkawa, the experiments showed that the spin packets are carried by negative – not positive – charge, indicating that spin was carried by electrons.

Ozone mystery is solved

In theory, the creation of ozone – caused by the breakdown of oxygen in the atmosphere by ultraviolet light – is a mass-independent process. However, experiments by Klaus Mauersberger and colleagues at the Max-Planck institute for nuclear physics in Heidelberg indicate that the collisions between oxygen atoms and molecules that form ozone are not mass-independent (Science 283 370).

The German researchers studied the six different atom-molecule reactions that lead to the formation of ozone. By creating ozone in a series of different gas mixtures, each containing different amounts of the three oxygen isotopes, the German group was able to study the reaction rates for each isotope. It found that the reaction rate for creating heavy molecules of ozone was up to 50% higher than that for creating lighter versions.

Patents for microlasers

The world-wide patent rights have been licensed by the university to Nanovation Technologies in Florida. The company hopes to develop an optical circuit which would contain thousands of microcavity lasers on a single semiconductor chip. Tests carried out by the company at Northwestern suggest that such a chip could increase the speed and information capacity of existing chip technology by at least a hundred-fold. In return for the patent rights Nanovation Technologies financed the construction of a state-of-the-art nanofabrication laboratory and clean room on the university campus – the first such facility dedicated to nanophotonics research in the US.

New leaders for SLAC and ESO

Dorfan was born in South Africa and received his first degree from the University of Cape Town, and his doctorate from the University of California at Irvine in 1976. He has spent most of his career at Stanford, most recently as leader of the B-factory project at SLAC.

Cesarsky was born in France in 1943. She received her first degree from the University of Buenos Aires in Argentina and her PhD from Harvard University in the US. Since 1994 she has been director of the materials science division of the French atomic energy agency and in charge of over 3000 scientists and engineers working on a variety of basic research problems in physics, astrophysics, chemistry and earth sciences. Cesarsky is currently vice-president of the International Astronomical Union.

Fifth framework to start soon

The fifth framework will focus on four main themes: quality of life and management of living systems (ECU 2.413 bn); the user-friendly information society (ECU 3.6 bn); competitive and sustainable growth (ECU 2.705 bn); and energy, environment and sustainable development (ECU 2.125 bn). Its three other main activities are: confirming the international role of community research (ECU 475m); promotion of innovation, encouragement of small and medium-sized enterprises (ECU 363m); and improving human research potential (ECU 1.28 bn). Some ECU 858 m will be available for postdoctoral researchers under the last of the activities. Fusion research will receive a further ECU 700 m.

Women sue Lawrence Livermore over equal opportunities

One of the women, Mary Singleton, has been complaining about the inequality for 20 years and says that in 1986 the lab’s management board admitted that female staff were discriminated against. However the board took no action. Singleton, who retired last year, used to manage Livermore’s plutonium facility. “The regents and management at the lab have known about this problem for a very long time and have simply refused to take appropriate action, ” she said.

Another of the women, Maura Spragge, was worried about the message being sent to would-be women scientists. “When we entered this field, we thought we were breaking something open, ” she said. “But I wouldn’t encourage a young woman to go into it with conditions as they are now.”

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