"The damage force of such an impact might equal 5,000 times that of the Hiroshima atomic bomb," according to Salameh, adding that it would have destroyed everything within a radius of hundreds of kilometres.

The crater consists of two concentric circles. The diameter of the outer ring measures around 5.5km, with the inner ring measuring 2.7km.

The impact size and velocity, according to Salameh, would have raised the atmospheric temperature within a radius of 10 kilometres to more than one thousand degrees centigrade, spewing millions of tonnes of rocks, vapour, dust and smoke into the atmosphere.

This in turn would have formed an atmospheric cloud so large as to plunge the entire earth into darkness, with continuous rain for months or even years, resulting in the widespread flooding of low lands, according to a statement by the University of Jordan.

The discovery is thought to be the largest such meteorite crater in the region.

Future research at the site, which has been well-preserved due to the area's dry climate, will be supported by the University of Jordan and the Higher Council for Science and Technology.

Highlighting the importance of the find, Salameh said the site is expected to explain many geologic and historic features and events such as calcinated rocks, molten rock, highly jointed and cracked rocks.

There are around 130 crater structures of impact origin in the world. One of the oldest and largest clearly visible sites is the Vredefort Dome, located in South Africa.

The original crater, now eroded, was probably 250 to 300 kilometres in diameter, larger than the Sudbury impact structure in Canada, about 200km in diameter.

At two billion years old, Vredefort is far older than the Chixculub structure in Mexico which, with an age of 65 million years, is the site of the impact that is said to have led to the extinction of the dinosaurs.

All relevant institutions in Jordan have been informed about the discovery, including the Badia Project, the Department of Lands and Survey and the Natural Resources Authority, in order to take the necessary steps to conserve the site.

William Worwor at Vanuatu's met service says there would have been very little time to warn of a possible tsunami.

"If a tsunami was generated - some of the islands that were very close to the epicentre would have already been struck by a tsunami."

The town has experienced several earthquake in recent years. Weather and seismic agency KNMI and local broadcaster RTV Noord were bombarded with telephone calls and emails from concerned residents after the latest
quake.

Hein Haak said the earthquake was the largest ever measured in Groningen and was felt across the entire province.

There have been 10 quakes roughly equivalent to this magnitude since the first earthquake caused by the gas drilling took place in 1986. There have been several dozen smaller shooks during this period too.

The earthquakes result from tension in the earth's crust caused by the extraction of gas. The tension increases in correlation to the amount of gas extraction. The first earthquake took place 27 years after drilling began in Groningen in 1959.

Researchers in Barbara Hohn's lab at the Friedrich Miescher Institute for Biomedical Research in Basel, Switzerland, study a process in which one piece of DNA within the genome replaces another fragment of similar sequence. This process, called 'homologous recombination', occurs more frequently in stressed plants. Plants grown near the site of the Chernobyl nuclear-reactor accident, for example, were found to have rates of homologous recombination that increased with the dose of radiation they received.

By chance, a student in Hohn's lab found that the rate of homologous recombination was curiously high in a particular batch of cress plant or Arabidopsis seeds. When he traced back the origin of the seeds, he discovered that the parent had been irradiated.

"Nobody set out to do this," says Hohn. "It was pure serendipity."

Stressful memories

After the accidental discovery, Hohn's group set out to examine what was going on. The team found that, as expected, giving a parental plant a burst of ultraviolet radiation or a simulated pathogen attack boosted the rate of homologous recombination in some of its cells. And when the change occurred in cells that are used to form the plants' offspring, all progeny carried the genetic change.

But, surprisingly, even if the cells used to create the progeny didn't carry the genetic change, the offspring of the stressed plants were still more likely to undergo homologous recombination in their own cells. They had inherited a tendency to mutate.

The memory of the initial stress lasted a long time; at least four generations had an increased level of homologous recombination.

Exactly how plants pass down this information is unknown. Hohn believes that the mechanism is 'epigenetic' - inheritance of a trait without a corresponding change in DNA sequence. Chemical modification of a plant's DNA that happens during its lifetime, for example, can be copied into the progeny's DNA. Or RNA, an intermediate that helps to convert DNA information into proteins, may be ferried from a parent's cells into its offspring's.

Hohn is quick to point out that her lab has not shown that the progeny of stressed parents are themselves more stress-tolerant, so it is unclear what advantage, if any, this inheritance gives the subsequent generations. "If the plants become UV-resistant or pathogen-resistant," she says, "that would be adaptive evolution." Hohn's lab hasn't yet tested whether this is so.

Staying put

It makes sense that plants would have elaborate strategies for coping with stress, says Christopher Cullis, a biologist at Case Western Reserve University in Cleveland, Ohio. "Plants can't get up and find somewhere nicer," says Cullis. "So they've got to find a way of coping with that stress." But he finds it surprising that a single burst of stress seems sufficient to trigger such a long-lasting response.

Eric Richards, a biology professor at Washington University in St Louis, says that results from Hohn's lab are intriguing. One interesting follow-up, he adds, is to check whether recombination has increased throughout the plant's entire genome. Hohn's lab is set up to look at just one specific gene, so they haven't yet taken this broader approach.

"I think there's probably a lot more of these inherited epigenetic phenomena out there than people think," says Richards, who himself studies plant epigenetics. "I guess it's now come to the point at which people are starting to take these things seriously."

"Savvy fragrance companies have realised that more discerning customers don't want to smell like everyone else," confirms Caroline Brien, beauty features editor at Marie Claire. "There's a small but significant trend for fragrances that don't conform to tradition, and it's a trend that's growing."

The most recent - and definitely most surprising - launch captures the smell of Stilton cheese. Said to be chasing Cat Deeley as its 'face', Eau de Stilton is a 'distinctive' olfactory blend of notes including clary sage, yarrow and angelica seed (www.stiltoncheese.com).

Elsewhere, aged rockers Kiss are to launch their own fragrance line this autumn, containing a heady whiff of sweat and pheromones, along with sinful accords of bare skin and patent leather.

One is only left to imagine what Marilyn Manson's hotly-awaited perfume is going to smell like.

Christopher Brosius, meanwhile, is the innovative perfumer who created Demeter - the influential American perfume house known for bottling such singular experiences as Fireplace, Dirt, and Sex On The Beach.

Now with his own range of fragrances, rather candidly called C.B. I Hate Perfume, Brosius's creations are closer to art than commerce, and provide truly conceptual olfactive experiences (www.cbihateperfume.com).

Fragrances such as At The Beach 1966, Winter 1972, and In The Library are sure to trigger an emotional experience far greater than any combination of rose, raspberry and vanilla. This trend is not so much about smelling 'nice' but making a statement of individuality.

While he may not necessarily endorse such outlandish concoctions, fragrance expert Roja Dove, whose Haute Parfumerie at Harrods (020 7893 8797) houses many of the world's most highly-coveted perfumes, does note the wider trend that such fragrances are part of.

Individuality

"Why has our perfumery been so successful? Without question, I think it's because so many people are fed up with everything smelling the same. There's no individuality any more."

Traditionally, perfumery used to depend on the discovery of natural ingredients but today - with few parts of the world left unexplored - the prevalence of undiscovered materials is rare. It is now falling to unconventional synthetic ingredients to push the industry forward.

Fashion house Comme des Garcons has pioneered this area, by creating scents based on dry cleaning, sherbet and tar, to name a few. Far from being a wacky experiment, its perfumes have gained a popular following.

This summer the label re-launched two of its most revolutionary fragrances at Harvey Nichols stores nationwide (020 7499 4420). Both described as 'anti-perfumes', Odeur 71, £55, captures inorganic smells of 'dust on a hot light-bulb', 'warm photocopier toner' and 'fresh pencil shavings'; while Odeur 53, £52, is a surprisingly fragrant blend of concept smells such as 'flaming rock', 'flash of metal' and nail polish.

"In terms of unusual notes, both the industry and consumers have evolved past accepting the quirky scents such as dirt or grass (both by Demeter) that had a hip following in the Nineties," says Marie Claire's Caroline Brien.

"Today, these kind of notes have to add depth to a perfume or have enough character to stand up alone, increasingly delivering the obscure scent they promise on the bottle."

Rather fittingly, then, one of the latest underground fragrance launches does just that. Possibly the most unconventional of all perfumes, Molecule 01 by Escentric Molecules isn't a fragrance (usually a blend of as many as 100 components) at all, but a solitary synthetic scent - the aroma chemical Iso E Super, which has a pheromone effect.

"It's certainly a new thing, the idea that you can wear a single molecule on its own," says Geza Schoen, the nose and creator behind Escentric Molecules. "Even I was surprised how popular it was, because it was meant to be for people who wanted a feeling more than an actual fragrance. But that's what they like, they like that it's different."

Molecule 01, which is more of an effect than an aroma, along with its counterpart fragrance Escentric 01, blended with pink pepper, lime and incense, (020 7235 5000), has become a phenomenon.

With worldwide waiting lists, and a bevy of fans including Madonna, Elton and David, Dita von Teese and Kate Moss - who ordered a case of the stuff - these highly-addictive, pheromonic concoctions, both £59, are proof of the growing popularity of rebel perfumes.

"It's incredible because we're a brand that nobody knows, but that doesn't seem to matter," says Geza Schoen.

"People just like the fragrance and they even ask other people wearing it on the street what it is. Ten years ago the industry was all about the big perfumery brands. Now things have become more individualistic and perfumers can start to make a statement."

Scientists from the National Institute of Mental Health (NIMH) injected 17 patients with either a very low dose of ketamine or a placebo of saline solution.

The participants were all depression sufferers who had tried an average of six treatments that had failed.

The researchers then measured their levels of depression minutes, hours and days after the dose was given.

Lead researcher Dr Carlos Zarate Junior, head of the mood and anxiety disorders programme at NIMH, said: "Within 110 minutes, half of the patients given ketamine showed a 50% decrease in symptoms."

By the end of day one, he added, 71% had responded to the drug. And at this point the team found 29% of these patients were nearly symptom free.

The researchers also discovered one dose lasted for at least a week in more than one-third of the participants.

Brain pathways

Dr Thomas Insel, director of NIMH, commented: "To my knowledge, this is the first report of any medication or other treatment that results in such a pronounced, rapid, prolonged response with a single dose.

"These were very treatment-resistant patients."

Many antidepressants target levels of brain chemicals, such as serotonin and dopamine, and, over time, the accumulation of these chemicals can affect a patient's mood. But this can take several weeks.

But the team believes ketamine is having a faster effect because it is targeting a different brain-protein, called the NMDA receptor, which is thought to play a critical role in learning and memory.

The team says ketamine, in its current form, would not be appropriate for medication because of side-effects at higher doses, which include hallucinations and euphoria.

Dr Zarate said: "This study is a tool to help us understand what part of ketamine is causing this effect so we can refine and develop better drugs.

"We are also looking at ways that we could use ketamine maybe in lower doses or with drugs that block its perceptual effects so we could perhaps use it clinically."

Professor John Henry, a clinical toxicologist at St Mary's Hospital in London, said: "This is a very interesting piece of work, very neatly done, with promising results.

"More studies need to be done to see if ketamine would work over a longer period given in repeated doses.

"The benefit of having a fast-working drug would mean people could return to work quickly, and it could reduce risk of self-harm or suicide that could happen during the time-lag that occurs with other drugs."

"The bites of a yellow sack spider are indeed painful but not deadly," Health Minister Maria Rauch-Kallat said in a statement. "If you are bitten, please don't panic and in case of discomfort immediately contact a doctor."

Underscoring the hysteria, 190 people who feared they might have been bitten went Wendesday to the main hospital in the northwestern city of Linz. Only eight of them turned out to have possible symptoms, doctors told Austrian state broadcaster ORF.

Eva Reiner, a Vienna business consultant, fished a dead yellow sack spider out of her pool this week _ and has not gone swimming since.

"It wasn't even alive, and it still looked evil to me," she said.

But experts are urging people to keep things in perspective.

The yellow and brown striped critter, whose Latin name is Cheiracanthium Punctorium and is known in German as a "Dornfingerspinne," is one of 1,000 similar species found in Austria and neighboring countries including Germany, Italy and Switzerland, said Christian Komposch of an animal ecology institute in the southern city of Graz.

There are sightings every year, said Komposch, who blames the media for spreading misleading information and fanning the frenzy.

Dr. Christian Baldinger, a physician in the province of Upper Austria, said he was bitten last week while working in his garden.

"It was like a stinging nettle, but not really painful," said Baldinger, 53. Within two days, the wound was red and infected, and a specialist told him the symptoms could take eight to 10 weeks to subside.

Komposch advises people who think they may have been bitten to treat the wound with hot water.

"The most important thing is: Don't panic!" he said.

For the not-so-faint at heart, the spider could bring in some cash.

Collectors are willing to fork over more than $255 for a single specimen, according to Kurier, an Austrian daily.

But some people, such as 26-year-old bank employee Robert Schneider, do not know what all the fuss is about.

"I think everyone is exaggerating," he said. "I'm not sure I would recognize a yellow sack spider if I saw one."