Theoretically...

Time to move... from next week, the Science page will be enlarged and incorporated in the Network section of the tabloid in Tuesday's Independent.

Tomorrow should see the launch, weather permitting, of the second repair mission for the Hubble Space Telescope. During the 10-day mission, the seven Space Shuttle crew will carry out at least four spacewalks and install two new astronomy instruments. These should allow it to gather 30 times more spectral data and 500 times more spatial data than existing instruments. One of their best applications will be the study of supermassive black holes. The HST, launched in 1990, was last fixed in 1993, and is expected to last until 2005.

Turning against the worm, a team of plant breeders in Germany, Denmark and the Netherlands have discovered a gene which renders plants resistant to nematodes - microscopic worms which destroy about pounds 70bn worth of crops worldwide every year. The work, reported in Science, followed the team's cloning of a gene which confers resistance to nematodes in wild beet plants. When transferred to sugar beets, the gene provides the same protection.

Seven years after its start, the project to sequence the whole genome of Escherichia coli, the bacterium more usually known as E. coli, has been completed. Nature reports that two teams, one in the US and another in Japan, have put their sequence data into public databases. Analysis shows that it contains many genes with unknown function, but Gordon Dougan, of Imperial College London, told Nature that it will be a useful guide to the "evolution of virulence" of these common gut flora.

The "flashbulb" effect of famous events, in which you remember everything about remarkable occasions, such as where you were when you heard that Kennedy had been shot, is probably caused by strong emotions. According to a report in Nature, teams in Germany and Edinburgh found that proteins which help form the neuronal connections that become our memories are released in a wave during strong stimulation. The process is indiscriminate, so we remember very well any occasion that sparks strong emotions.

American scientists have built the key elements of a computer that would run on DNA. Researchers at the University of Rochester in upstate New York created short sequences of DNA which performed the same function as logic gates in electronic computers. The work, reported in New Scientist, could lead to "DNA computers" which could potentially contain more computing power in a drop of water than in the world's biggest electronic supercomputer.