New dinosaur discovery solves evolutionary bird puzzle

A newly discovered fossil has shed light on why a group of dinosaurs looks like birds, say scientists.

Haplocheirus sollers may not be as charismatic as T. rex or as agile as a pterodactyl but it's thought to solve a long standing puzzle.

Researchers believe its short arms and large claw show how bird-like dinosaurs evolved independently of birds.

The 3m-long skeleton, found on an expedition to China's Gobi desert, is described in the journal Science.

The fossil is a member of the Alvarezsauridae family, a group of bird-like dinosaurs. The group shares features with birds, including fused wrist elements and a loosely structured skull.

But the researchers say the new fossil shows the Alvarezsauridae group split from birds much earlier on the evolutionary tree than was thought.

"Haplocheirus is a transitional fossil," Jonah Choiniere from George Washington University told the BBC.

"Previously we thought the Alvarezsauridae were primitive, flightless birds. This discovery shows they're not and that the similarities between them evolved in parallel."

The fossil is of a nearly complete adolescent dinosaur skeleton and was found in orange mudstone beds in the Junggar Basin, Xinjiang, China.

It was spotted when a member of the team noticed the pelvis at the ground's surface. The rest of the skeleton was found only inches down.

The new dinosaur shows an early evolutionary step in the development of the short, powerful arm typical to the Alvarezsauridae group.

"The rest of the members of this group have really short forelimbs with huge muscle attachments, like body-builder arms. The fossil shows the first step in the evolution of this weird arm and claw," said Mr Choiniere.

Varied diet

The researchers believe the fossil shows development of the two diverged in the Late Jurassic period, about 160 million years ago. Until now there was no evidence of this type of dinosaur living at that time.

"It's like finding a great, great grandfather in your family which doubles the age of your family tree," said Mr Choiniere.

Scientists believe that birds descended from theropods or bird footed dinosaurs in the Late Jurassic. Theropods include alvarezsaurs, other bird-like dinosaurs including the well known Velociraptor, meat eaters like T. rex and modern birds.

Haplocheirus sollers means simple, skillful hand. The fossil shows the dinosaur had small teeth and researchers believe the claw may have been used for digging termites.

"It may have had a very general diet, tackling smaller animals like lizards, very small mammals and very small crocodile relatives," explained Mr Choiniere. "It was a lightly built animal and could run very quickly."

Laser fusion test results raise energy hopes

A major hurdle to producing fusion energy using lasers has been swept aside, results in a new report show.

The controlled fusion of atoms - creating conditions like those in our Sun - has long been touted as a possible revolutionary energy source.

However, there have been doubts about the use of powerful lasers for fusion energy because the "plasma" they create could interrupt the fusion.

An article in Science showed the plasma is far less of a problem than expected.

The report is based on the first experiments from the National Ignition Facility (Nif) in the US that used all 192 of its laser beams.

Along the way, the experiments smashed the record for the highest energy from a laser - by a factor of 20.

Star power

Construction of the National Ignition Facility began at Lawrence Livermore National Laboratory in 1997, and was formally completed in May 2008.

The goal, as its name implies, is to harness the power of the largest laser ever built to start "ignition" - effectively a carefully controlled thermonuclear explosion.

INERTIAL CONFINEMENT FUSION 192 laser beams are focused through holes in a target container called a hohlraum Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes Lasers strike the hohlraum's walls, which in turn radiate X-rays X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees If the compression of the fuel is high enough and uniform enough, nuclear fusion can result Giant laser experiment powers up

It is markedly different from current nuclear power, which operates through splitting atoms - fission - rather than squashing them together in fusion.

Proving that such a lab-based fusion reaction can release more energy than is required to start it - rising above the so-called breakeven point - could herald a new era in large-scale energy production.

In the approach Nif takes, called inertial confinement fusion, the target is a centimetre-scale cylinder of gold called a hohlraum.

It contains a tiny pellet of fuel made from an isotope of hydrogen called deuterium.

During 30 years of the laser fusion debate, one significant potential hurdle to the process has been the "plasma" that the lasers will create in the hohlraum.

The fear has been that the plasma, a roiling soup of charged particles, would interrupt the target's ability to absorb the lasers' energy and funnel it uniformly into the fuel, compressing it and causing ignition.

Siegfried Glenzer, the Nif plasma scientist, led a team to test that theory, smashing records along the way.

"We hit it with 669 kiloJoules - 20 times more than any previous laser facility," Nif's Siegfried Glenzer told BBC News.

That isn't that much total energy; it's about enough to boil a one-litre kettle twice over.

However, the beams delivered their energy in pulses lasting a little more than 10 billionths of a second.

By way of comparison, if that power could be maintained, it would boil the contents of more than 50 Olympic-sized swimming pools in a second.

'Dramatic step'

Crucially, the recent experiments provided proof that the plasma did not reduce the hohlraum's ability to absorb the incident laser light; it absorbed about 95%.

But more than that, Dr Glenzer's team discovered that the plasma can actually be carefully manipulated to increase the uniformity of the compression.

The 130-tonne target chamber is kept under vacuum for the experiments

"For the first time ever in the 50-year journey of laser fusion, these laser-plasma interactions have been shown to be less of a problem than predicted, not more," said Mike Dunne, director of the UK's Central Laser Facility and leader of the European laser fusion effort known as HiPER.

"I can't overstate how dramatic a step that is," he told BBC News. "Many people a year ago were saying the project would be dead by now."

Adding momentum to the ignition quest, Lawrence Livermore National Laboratory announced on Wednesday that, since the Science results were first obtained, the pulse energy record had been smashed again.

They now report an energy of one megaJoule on target - 50% higher than the amount reported in Science.

The current calculations show that about 1.2 megaJoules of energy will be enough for ignition, and currently Nif can run as high as 1.8 megaJoules.

Dr Glenzer said that experiments using slightly larger hohlraums with fusion-ready fuel pellets - including a mix of the hydrogen isotopes deuterium as well as tritium - should begin before May, slowly ramping up to the 1.2 megaJoule mark.

"The bottom line is that we can extrapolate those data to the experiments we are planning this year the results show that we will be able to drive the capsule towards ignition," said Dr Glenzer.

Before those experiments can even begin, however, the target chamber must be prepared with shields that can block the copious neutrons that a fusion reaction would produce.

But Dr Glenzer is confident that with everything in place, ignition is on the horizon.

He added, quite simply, "It's going to happen this year."

Ginkgo biloba's epilepsy seizures warning

People with epilepsy should be warned that using a popular herbal remedy may increase the risk of seizures, researchers say.

German scientists, writing in the Journal of Natural Products, said they had found 10 written reports of seizures linked to ginkgo biloba.

They said they were convinced the herb could have a "detrimental effect".

A leading UK epilepsy charity said the evidence was not yet compelling, although it said care was needed.

Ginkgo biloba remedies - made from the leaves of the tree of the same name - is used by many thousands of people in the UK as a remedy for health problems ranging from depression and memory loss, to headaches and dizziness.

The team from the University of Bonn focused on a particular chemical compound in the herb called ginkgotoxin.

They said that evidence suggested that it might alter a chemical-signaling pathway in the body linked to epileptic seizures, and potentially interfere with the effectiveness of anti-seizure medications.

In addition to any benefits, which still remained unproven, they wrote, there was a "clear potential for adverse effects", particularly in susceptible patients

Even though there was no definitive proof that the herb had been the cause of the increase in seizures in the reported cases, patients should be warned about the possibility, and manufacturers asked to test their ginkgo products for levels of the toxin.

'Be aware'

Professor John Duncan, from the National Society for Epilepsy, said that the current evidence did not necessarily warrant restrictions on the use of the remedy.

He said: "We believe that some herbs, for example St John's wort, are linked to a higher risk of seizures, but there is still not a great deal of evidence about problems related to ginkgo.

"We would say that if someone who has epilepsy wants to take this remedy, they should simply be aware of the possibility."