Three hundred years ago, more or less, the last serious alchemists finally gave up on their attempts to create gold from other metals, dropping the curtain on one of the least successful endeavors in the history of human striving.

Centuries of work and scholarship had been plowed into alchemical pursuits, and for what? Countless ruined cauldrons, a long trail of empty mystical symbols, and precisely zero ounces of transmuted gold. As a legacy, alchemy ranks above even fantasy baseball as a great human icon of misspent mental energy.

But was it really such a waste? A new generation of scholars is taking a closer look at a discipline that captivated some of the greatest minds of the Renaissance. And in a field that modern thinkers had dismissed as a folly driven by superstition and greed, they now see something quite different.

Alchemists, they are finding, can take credit for a long roster of genuine chemical achievements, as well as the techniques that would prove essential to the birth of modern lab science. In alchemists' intricate notes and diagrams, they see the early attempt to codify and hand down experimental knowledge. In the practices of alchemical workshops, they find a masterly refinement of distillation, sublimation, and other techniques still important in modern laboratories.

A research team used lasers to produce more positrons (anti-electrons) inside a solid than any previous experiment, according to the researchers involved. In the 13 March Physical Review Letters, the team describes firing short pulses from an intense laser onto thin gold targets and creating a high-density positron source that could be used to investigate exotic phenomena near black holes or supernovae.

Researchers currently produce positrons using one of two methods. At low energies, from a few to a few thousand electron-volts, they are obtained from radioactive isotopes, as in positron emission tomography (PET), a medical imaging technique. Alternatively, particle accelerators can produce positrons with energies of billions of electron-volts.

Hui Chen and Scott Wilks of the Lawrence Livermore National Laboratory in California and their colleagues now report that they have generated copious amounts of positrons with intermediate energies--in the range of a million electron-volts. They fired picosecond pulses with intensities of around 1020 watts per square centimeter from the Titan laser at Livermore's Jupiter laser facility onto millimeter-thick gold targets. Positrons were produced via the "Bethe-Heitler" process, in which part of each laser pulse creates a plasma on the surface of the target, and the remaining part of the pulse then blasts electrons from the plasma into the solid. Next, the electrons are slowed down by gold nuclei, an interaction that generates gamma-ray photons. The gamma rays then interact with more gold nuclei and transform into electron-positron pairs.

Is the day approaching when the U.S. military can deploy a robot that can drive itself around a corner, use sensors to detect an enemy fighter on-the-move and destroy the target instantly with missiles and machine guns - all without human intervention? The Pentagon thinks the day may be imminent and it wants to make ensure that its technology doesn't get ahead of military doctrine. It wants to be certain that there is always a "human" making decisions regarding the use of lethal force.

With some estimates of armed robots, with so-called Autonomous Navigation Systems, less than five years away, the U.S. Army is drafting a "White Paper," to establish a set of guidelines and principles for their use. "This is a concept paper to think about warfighting outcomes and what robotics will do for soldiers," says U.S. Army Lt. Gen. Michael Vane, who directs the Army Capabilities Integration Center, Fort Monroe, Va. "I am starting out with the idea of having an technology-enabled human. [But] we might someday come up with [separate] IT doctrine and robot doctrine." He reiterates that "we want to make the people or humans in charge under command and control in a 'whole of government' approach." The White Paper will be finished in the coming weeks, Army officials said. (See the most memorable movie robots.)

If you want to buy an electric car, you can. Tesla Motors, a firm based in San Carlos, California, will sell you a nifty open-top sports job for $109,000. Not cheap, admittedly, but cheap to run. Plugged in overnight, it can be refuelled for the equivalent of 25 cents a litre of petrol. The catch is, "plugged in overnight". Tesla's vehicles use standard lithium-ion battery cells. As any owner of a mobile phone or laptop computer knows, these take time to charge. If you use 6,831 of them, as a Tesla sports car does, that time does tend to drag on. Which is fine if you are not planning a long trip the following day, for a full charge will take you about 350km (220 miles). But it might cramp the style of anyone planning to bomb down from, say, Paris to Cannes, and who would therefore need to refuel on the way.

Gerbrand Ceder and Byoungwoo Kang of the Massachusetts Institute of Technology hope to change this, and thus help make the electric car a work-a-day consumer item, rather than a high-end boy's toy. In this week's Nature they have published the technical details of a new battery material that will, if all goes well, take the waiting out of wanting, at least when it comes to recharging.

Broadly speaking, there are two ways of storing electrical energy in a chemical system. One is a standard battery, in which the whole material of the electrodes acts as a storage medium. That allows lots of energy to be squirrelled away, but makes it relatively hard to get at - and so it can be released or put back in only slowly. The other way is called a supercapacitor. This stores energy only at the surface of the electrode. It is quick to charge and discharge, but cannot hold much energy. The great prize in the battery world has thus been a material that can both store a lot and discharge rapidly, and it is this that Dr Ceder and Mr Kang think they have come up with.

Washington - Every winter, David DeWitt takes his biology class to the Smithsonian's National Museum of Natural History, but for a purpose far different from that of other professors.

DeWitt brings his Advanced Creation Studies class up from Liberty University in Lynchburg, Va., hoping to strengthen his students' belief in a biblical view of natural history, even in the lion's den of evolution.

His yearly visit is part of a wider movement by creationists to confront Darwinism in some of its most redoubtable secular strongholds. As scientists celebrate the 200th anniversary of Charles Darwin's birth, his doubters are taking themselves on Genesis-based tours of natural history museums, aquariums, geologic sites and even dinosaur parks.

We are gradually beginning to understand what happened to the elite body of artisans that worked on the royal tombs in the Valley of the Kings after they ceased to be built, says Jill Kamil

It appears that the workers, or should we say workmen and artisans, the people who built the rock-cut tombs of the Pharaohs in the Valley of the Kings from about 1500 BC onwards, may have later been employed on a project aimed at "emptying" and "recycling" their contents -- or that, at least, is what Rob Demaree of Leiden University thinks.

For years we've been writing about various abuses of the patent system, and how they damage innovation. There are times when we hear about abuses of the patent system that actually put lives in danger -- often around the pharmaceutical industry. At least in that case, you can sometimes understand the basic reasoning (even if it's actually incorrect). However, we recently came across an example of the patent system being abused in such an egregious manner that it's putting many lives at stake.

Traces of an unknown lifeform have been found in rocks in a secret location in Devon in south west England.

The animal, which made large burrows through sediment at the bottom of desert wadis in Torbay some 260 million years ago, could be unknown to science.

Scientists from around the world will be informed of the mystery when the findings are officially published later this year.

It comes as nine other sites in the area have been officially recognised as of national and international importance geologically.

Geologist Kevin Page from Plymouth University, said they had been unable to find any known animal, alive or extinct, that would have been responsible for the kind of burrows found in the deposits.

Sunshine may not cure all ills, but it could offer a quick fix for a scratched car. Scientists have used a substance from the shells of shrimp to create a new material that repairs itself when exposed to ultraviolet light. The properties of the polymer, described in the March 13 Science, are still being investigated, but it could in a matter of years make its way into all kinds of coatings, such as paints, and surfaces on everything from surgical instruments to countertops.

"It's some interesting chemistry," comments Nancy Sottos, a materials scientist at the University of Illinois at Urbana-Champaign. The self-repair market is big with a lot of potential applications, she says.

Scholarship suggesting the existence of the Essenes, a religious Jewish group that lived in the Judea before the destruction of the Second Temple in 70 CE, is wrong, according to Prof. Rachel Elior, whose study on the subject will be released soon.

Elior blasts the predominant opinion of Dead Sea Scrolls scholars that the Essenes had written the scrolls in Qumran, claiming instead that they were written by ousted Temple priests in Jerusalem.

"Sixty years of research have been wasted trying to find the Essenes in the scrolls. But they didn't exist, they were invented by [Jewish-Roman historian] Josephus. It's a history of errors which is simply nonsense," she said.