Convertibles 'bad for the ears'

Top down driving can be too noisy Driving a convertible car can seriously damage your ears, experts have warned. Cruising with the top down at speeds of 50-70mph (80-112km/h) exposes the ears to sound levels sometimes nearing those made by a pneumatic drill, they argue. Long or repeated exposure to this noise of the engine, road, traffic and wind could cause permanent hearing loss, a US meeting of ENT experts was told. Researchers said convertible drivers should consider wearing some form of ear protection, as motorcyclists do. The research has been published in the journal Otolaryngology - Head and Neck Surgery. In the study, noise levels immediately to the left and right of the driver were measured while travelling at different speeds. At 50, 60 and 70 miles per hour, the noise reached between 88 and 90 decibels - higher than the generally agreed 85 decibel threshold level at which permanent hearing damage becomes a risk. Noise levels A quiet room at night - 20 decibels An ordinary spoken conversation - 60 decibels A busy street - 70 decibels Shouting - 80 decibels A pneumatic drill - 110 decibels Aircraft taking off - 130 decibels Source: The Royal National Institute for Deaf People The researchers repeated the test with a range of convertibles, on the same stretch of motorway, outside of rush hour, and found the same noise levels - around 90 decibels, with a high of 99 decibels. But they also found motorists can cut the noise by rolling up the windows when driving with the top down. This simple measure cut the level to 82 decibels. Experts warned that the damage to hearing builds up gradually and the effects may not be noticed until years later, when it is too late. Dr Mark Downs, of the Royal National Institute for Deaf People, said: "Noise-induced hearing loss is frequently preventable. "Regular exposure to noise levels of 88-90 decibels when driving a convertible for several hours a day can lead to permanent hearing loss over time. "By winding up the windows or wearing basic ear protection, such as earplugs, drivers of convertibles can still enjoy driving whilst protecting their hearing."

How clean is your keyboard?

Computer keyboards can host more harmful bacteria than an average toilet seat.

Kerina Fitzgerald from Duston in Northampton works in a call centre. She feels ill after catching an ear infection from shared use of a telephone head set. She understands the seriousness of cleaning your work station effectively to protect yourself at work.

"I've been working for my company for over five years and never caught an infection before. I would eat my lunch at my desk not knowing the risk I was opening myself to. Then after catching an ear infection we are now issued with individual head sets to prevent this from happening again."

"I now make sure I always wipe down my keyboard before I use it and am a lot more careful."

Jimoh sitting at computer desk

A computing magazine 'Which' turned the microscope on over 30 keyboards in a typical office and found some had harmful bacteria that could put their users at high risk of becoming ill. In one case, a microbiologist recommended the removal of a keyboard as it had 150 times the pass limit of bacteria, and was five times filthier than a toilet seat that was swabbed.

The germs found could cause food poisoning symptoms such as diarrhoea and other stomach upsets. The main cause of a bug-infested keyboard is eating lunch at desks and poor personal hygiene, such as dodging the hand washing basin after going to the toilet.

Despite the obvious health hazard of a dirty keyboard, how often people clean their computers varies widely. One in ten people say they never clean their keyboard with a further 20 per cent admitting to never cleaning their mouse.

What can you do to prevent your computer from becoming a health hazard?

• Before you start cleaning, shut down the computer and unplug it.
• Gently wipe surfaces with a soft, lint-free cloth. Lightly dampen (not wet) the cloth with a small amount of water or an approved computer cleaning fluid.
• Unplug your keyboard, turn it upside down and shake out any loose dust and food crumbs inside. Disinfect the surface with alcohol wipes.
• Use a vacuum cleaner with a rubber or brush nozzle on exterior surfaces and vents.
• Headphones can be used by multiple people and can spread germs or even head lice. Wipe them with a damp cloth.

Space debris' orbits Earth

Between the launch of Sputnik in 1957 and 2008, around 6,000 satellites have been launched into orbit. These computer-generated photos show all the junk orbiting Earth.

It's estimated that only 800 satellites are working. The debris also includes hundreds of bits of space shuttles that have exploded, broken off or been abandoned.

Eighty per cent of all space junk is around 1,200 miles above Earth or in low-Earth orbit (LEO). Spacecraft have to orbit at low altitude to avoid all the debris.

The view over the North Pole. Dead or inactive spacecraft and other objects range in size from the big (or about the size of a car) to the tiny (about the size of microscopic dust).

A view of the equator seen through a computer-animated image of space rubbish. The European Space Agency uses this database to get satellites in orbit undamaged

Tiny magnets used in anti-cancer gene therapy

LONDON (Reuters) - Tiny magnets have been used to deliver anti-cancer gene therapy in mice in a development that could make the treatment much more effective, scientists said on Thursday.

The idea behind gene therapy is to replace faulty genes. But the approach has had mixed success because of the difficulty of getting genes to the right part of the body.

One option has been to use viruses to carry genes but this risks triggering an immune system reaction.

Now British researchers think they may have cracked the problem.

By inserting magnetic nanoparticles into monocytes -- a type of white blood cell -- and injecting them into the bloodstream, they have been able to guide them around the body using an external magnet.

Using this technique, many more cells armed with anti-cancer genes reached and invaded malignant tumors, Claire Lewis of the University of Sheffield and colleagues reported in the journal Gene Therapy.

"The use of nanoparticles to enhance the uptake of therapeutically armed cells by tumors could herald a new era in gene therapy -- one in which delivery of the gene therapy vector to the diseased site is much more effective," Lewis said.

The new approach could also be used to deliver therapeutic genes to treat other conditions like arthritic joints or heart disease, she believes.

Clinical trials on humans, however, are still some way off.

Tests so far have involved treating tumors just under the skin of mice. The real goal is to attack tumors deep inside the body, which are normally the most serious.

"We're going to have to extend existing magnetic resonance, or MRI, technology to create a magnetic gradient over a deep tissue like the liver," Lewis said in a telephone interview.

Her team is also looking at the ability of magnetic targeting to deliver a variety of different cancer-fighting genes, including ones which could stop the spread of tumors to other parts of the body.

Gene therapy has been much hyped over the years as a treatment for cancer and other diseases where DNA is known to play a central role but scientists have run into a series of technical and safety problems.

In one trial in 1999 a patient died and in other cases children have developed leukemia as a result of such treatment.

"We would hope that this will be safer because we are using a natural mechanism in the body and patients' own white blood cells to deliver the gene therapy," Lewis said. "We're simply amplifying that with this magnetic approach."

Angler catches heavyweight carp

After taking a photograph, Mr Bird released Two Tone back into the la

An angler in east Kent has landed a 67lb carp after trying to catch it for eight years.

John Bird, 26, hauled in the huge fish at Connington Lake in his hometown of Ashford, at 0200 BST on Sunday.

If the British Record Fish Committee verify the catch, it will break its current record for the biggest freshwater fish landed in the UK.

Mr Bird released the gigantic carp, affectionately known to anglers as Two Tone, after taking a photograph.

He described catching Two Tone as a very emotional moment.

'Even larger'

"It was 2.30am when the bite alarm went off. Some 15 minutes later the fish was safely in the net. I only realised it was the record fish when I saw the colouring of its fins.

"I have had so many calls I had to turn my phone off at work, but it has been really great and I have been touched by all the messages of congratulations, " he added.

Two Tone, who was brought to Connington Lake in the late 80s by Mid Kent Fisheries, has been caught before at a slightly lighter weight.

Chris Logsdon, manager of Mid Kent Fisheries, said they expected him to grow even larger.

"This carp has been growing and growing over the last 20 years, and we hope to be the first water to get a 70lb carp."

Graphene Could Be the New Silicon

Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. It can be viewed as an atomic-scale chicken wire made of carbon atoms and their bonds. The name comes from GRAPHITE + -ENE; graphite itself consists of many graphene sheets stacked together.

The carbon-carbon bond length in graphene is approximately 1.42 Å. Graphene is the basic structural element of all other graphitic materials including graphite, carbon nanotubes and fullerenes. It is a large aromatic molecule, an extension of a family of flat polycyclic aromatic hydrocarbons called graphenes.

Recent investigations by physicists at the University of Maryland indicate that graphene—one-atom-thick sheets of carbon—could one day supplant silicon as the material of choice for important applications such as high-speed computer chips and biochemical sensors.

The research team, led by Michael Fuhrer, found that in graphene the intrinsic limit to the charge mobility, a measure of how well a material conducts electricity when subjected to an electric field, is higher than any other known material at room temperature. Graphene’s high mobility thus makes it promising for use in transistors that must switch extremely rapidly. If other factors that limit mobility in graphene, such as impurities, can be eliminated, its intrinsic mobility would be more than 100 times higher than that of silicon. The work was published online in the journal Nature Nanotechnology.

That’s not all that has emerged lately about this new "wonder" material. SciAm author Andre K. Geim and several co-workers report that by looking at the optical reflectivity of graphene they were able to find a way to measure the fine structure constant, alpha, the parameter that describes coupling between light and relativistic electrons.

Alpha is traditionally associated with quantum electrodynamics rather than condensed matter physics, which speaks to one of the truly unusual (even bizarre) aspects of graphene. The abstract of the paper was just posted on cond-mat.

Anyway you slice it, graphene is really hot right now.

Legend of the Crystal Skulls

Along with superstars like Harrison Ford, Cate Blanchett, and Shia LaBeouf, the newest Indiana Jones movie promises to showcase one of the most enigmatic classes of artifacts known to archaeologists, crystal skulls that first surfaced in the 19th century and that specialists attributed to various "ancient Mesoamerican" cultures. In this article, Smithsonian anthropologist Jane MacLaren Walsh shares her own adventures analyzing the artifacts that inspired Indiana Jones and the Kingdom of the Crystal Skull (in theaters May 22), and details her efforts tracking down a mysterious "obtainer of rare antiquities" who may have held the key to the origin of these exotic objects.

In 1992, this hollow rock-crystal skull was sent to the Smithsonian anonymously. A letter accompanying the 30-pound, 10-inch-high artifact suggested it was of Aztec origin. (James Di Loreto & Donald Hurlburt/Courtesy Smithsonian Institution)

Sixteen years ago, a heavy package addressed to the nonexistent "Smithsonian Inst. Curator, MezoAmerican Museum, Washington, D.C." was delivered to the National Museum of American History. It was accompanied by an unsigned letter stating: "This Aztec crystal skull, purported to be part of the Porfirio Díaz collection, was purchased in Mexico in 1960.... I am offering it to the Smithsonian without consideration." Richard Ahlborn, then curator of the Hispanic-American collections, knew of my expertise in Mexican archaeology and called me to ask whether I knew anything about the object--an eerie, milky-white crystal skull considerably larger than a human head.

I told him I knew of a life-sized crystal skull on display at the British Museum, and had seen a smaller version the Smithsonian had once exhibited as a fake. After we spent a few minutes puzzling over the meaning and significance of this unusual artifact, he asked whether the department of anthropology would be interested in accepting it for the national collections. I said yes without hesitation. If the skull turned out to be a genuine pre-Columbian Mesoamerican artifact, such a rare object should definitely become part of the national collections.

I couldn't have imagined then that this unsolicited donation would open an entirely new avenue of research for me. In the years since the package arrived, my investigation of this single skull has led me to research the history of pre-Columbian collections in museums around the world, and I have collaborated with a broad range of international scientists and museum curators who have also crossed paths with crystal skulls. Studying these artifacts has prompted new research into pre-Columbian lapidary (or stone-working) technology, particularly the carving of hard stones like jadeite and quartz.

Crystal skulls have undergone serious scholarly scrutiny, but they also excite the popular imagination because they seem so mysterious. Theories about their origins abound. Some believe the skulls are the handiwork of the Maya or Aztecs, but they have also become the subject of constant discussion on occult websites. Some insist that they originated on a sunken continent or in a far-away galaxy. And now they are poised to become archaeological superstars thanks to our celluloid colleague Indiana Jones, who will tackle the subject of our research in Indiana Jones and the Kingdom of the Crystal Skull. Details about the movie's plot are being closely guarded by the film's producers as I write this, but the Internet rumor mill has it that the crystal skull of the title is the creation of aliens.

The author and Scott Whittaker, director of the Smithsonian's Scanning Electron Microscope (SEM) Facility, examine the "Mitchell-Hedges Skull." Silicone molds of the skull's carved features were analyzed by SEM for evidence of tool marks. (James Di Loreto/Courtesy Smithsonian Institution)

These exotic carvings are usually attributed to pre-Columbian Mesoamerican cultures, but not a single crystal skull in a museum collection comes from a documented excavation, and they have little stylistic or technical relationship with any genuine pre-Columbian depictions of skulls, which are an important motif in Mesoamerican iconography.

They are intensely loved today by a large coterie of aging hippies and New Age devotees, but what is the truth behind the crystal skulls? Where did they come from, and why were they made?

Museums began collecting rock-crystal skulls during the second half of the nineteenth century, when no scientific archaeological excavations had been undertaken in Mexico and knowledge of real pre-Columbian artifacts was scarce. It was also a period that saw a burgeoning industry in faking pre-Columbian objects. When Smithsonian archaeologist W. H. Holmes visited Mexico City in 1884, he saw "relic shops" on every corner filled with fake ceramic vessels, whistles, and figurines. Two years later, Holmes warned about the abundance of fake pre-Columbian artifacts in museum collections in an article for the journal Science titled "The Trade in Spurious Mexican Antiquities."

French antiquarian Eugène Boban with his collection of Mesoamerican artifacts at an 1867 Paris exposition. Among the objects on display were two crystal skulls. At his feet rest a pot and a battleaxe Boban exhibited as Aztec. Both are fakes. (Courtesy Jane Walsh/Museo Nacional de Historia, Mexico City)

The first Mexican crystal skulls made their debut just before the 1863 French intervention, when Louis Napoleon's army invaded the country and installed Maximilian von Hapsburg of Austria as emperor. Usually they are small, not taller than 1.5 inches. The earliest specimen seems to be a British Museum crystal skull about an inch high that may have been acquired in 1856 by British banker Henry Christy.

Two other examples were exhibited in 1867 at the Exposition Universelle in Paris as part of the collection of Eugène Boban, perhaps the most mysterious figure in the history of the crystal skulls. A Frenchman who served as the official "archaeologist" of the Mexican court of Maximilian, Boban was also a member of the French Scientific Commission in Mexico, whose work the Paris Exposition was designed to highlight. (The exhibition was not entirely successful in showcasing Louis Napoleon's second empire, since its opening coincided with the execution of Maximilian by the forces of Mexican president Benito Juárez.)

One small crystal skull was purchased in 1874 for 28 pesos by Mexico City's national museum from the Mexican collector Luis Costantino, and another for 30 pesos in 1880. In 1886, the Smithsonian bought a small crystal skull, this one from the collection of Augustin Fischer, who had been Emperor Maximilian's secretary in Mexico. But it disappeared mysteriously from the collection some time after 1973. It had been on display in an exhibit of archaeological fakes after William Foshag, a Smithsonian mineralogist, realized in the 1950s that it had been carved with a modern lapidary wheel.

In 1886, the Smithsonian acquired a crystal skull that may have been a pre-Columbian bead re-carved in the 19th century. This catalogue entry shows the object at close to its actual size, and with a vertical drill hole through its center. (Courtesy of Paula Fleming Collection)

These small objects represent the "first generation" of crystal skulls, and they are all drilled through from top to bottom. The drill holes may in fact be pre-Columbian in origin, and the skulls may have been simple Mesoamerican quartz crystal beads, later re-carved for the European market as little mementos mori, or objects meant to remind their owners of the eventuality of death.

In my research into the provenance of crystal skulls, I kept encountering Boban's name. He arrived in Mexico in his teens and spent an idyllic youth conducting his own archaeological expeditions and collecting exotic birds. Boban fell in love with Mexican culture--becoming fluent in Spanish and Nahuatl, the Aztec language--and began to make his living selling archaeological artifacts and natural history specimens through a family business in Mexico City.

After returning to France, he opened an antiquities shop in Paris in the 1870s and sold a large part of his original Mexican archaeological collection to Alphonse Pinart, a French explorer and ethnographer. In 1878, Pinart donated the collection, which included three crystal skulls, to the Trocadero, the precursor of the Musée de l'Homme. Boban had acquired the third skull in the Pinart collection sometime after his return to Paris; it is several times larger than any of the others from this early period, measuring about 4 inches high. This skull, now in the Musée du Quai Branly, has a large hole drilled vertically through its center. There is a comparable, though smaller, skull (about 2.5 inches high) in a private collection. It serves as the base for a crucifix; the somewhat larger Quai Branly skull may have had a similar use.

Macabre Obsession
The 19th century was a period of keen fascination with skulls and skeletons in Europe. During the reign of Louis Napoleon (1852-1870), French artists created stereoscopic photographs, called Diableries, of miniature dioramas of skeletons at dress balls, libraries (below), conferences with the devil, and in amorous trysts. Wicked lampoons of corruption at Napoleon's court, they illustrate how popular skeletal imagery was when the first crystal skulls made their appearance. (Courtesy of Paula Fleming Collection)

A second-generation skull--life-size and without a vertical hole--first appeared in 1881 in the Paris shop of none other than Boban. This skull is just under 6 inches high. The description in the catalogue he published provided no findspot for the object and it is listed separately from his Mexican antiquities. Boban called it a "masterpiece" of lapidary technology, and noted that it was "unique in the world."

Despite being one of a kind, the skull failed to sell, so when Boban returned to Mexico City in 1885, after a 16-year absence, he took it with him. He exhibited it alongside a collection of actual human skulls in his shop, which he dubbed the "Museo Cientifico." According to local gossip, Boban tried to sell it to Mexico's national museum as an Aztec artifact, in partnership with Leopoldo Batres, whose official government title was protector of pre-Hispanic monuments. But the museum's curator assumed the skull was a glass fake and refused to purchase it. Then Batres denounced Boban as a fraud and accused him of smuggling antiquities.

In July 1886, the French antiquarian moved his museum business and collection to New York City and later held an auction of several thousand archaeological artifacts, colonial Mexican manuscripts, and a large library of books. Tiffany & Co. bought the crystal skull at this auction for $950. A decade later, Tiffany's sold it to the British Museum for the original purchase price. Interestingly, Boban's 1886 catalogue for the New York auction lists yet another crystal skull. Of the smaller variety, it is described as being from the "Valley of Mexico" and is listed with a crystal hand, which is described as Aztec. Neither of these objects can now be accounted for.

A third generation of skulls appeared some time before 1934, when Sidney Burney, a London art dealer, purchased a crystal skull of proportions almost identical to the specimen the British Museum bought from Tiffany's. There is no information about where he got it, but it is very nearly a replica of the British Museum skull--almost exactly the same shape, but with more detailed modeling of the eyes and the teeth. It also has a separate mandible, which puts it in a class by itself. In 1943, it was sold at Sotheby's in London to Frederick Arthur (Mike) Mitchell-Hedges, a well-to-do English deep-sea fisherman, explorer, and yarn-spinner extraordinaire.

Since the 1954 publication of Mitchell-Hedges's memoir, Danger My Ally, this third-generation, twentieth-century skull has acquired a Maya origin, as well as a number of fantastic, Indiana Jones-like tall tales. His adopted daughter, Anna Mitchell-Hedges, who died last year at the age of 100, cared for it for 60 years, occasionally exhibiting the skull privately for a fee. It is currently in the possession of her widower, but 10 nieces and nephews have also laid claim to it. Known as the Skull of Doom, the Skull of Love, or simply the Mitchell-Hedges Skull, it is said to emit blue lights from its eyes, and has reputedly crashed computer hard drives.

The Mitchell-Hedges skull, top, and the British Museum skull were the subject of a series of 1936 articles in which British Museum curator Adrian Digby and physical anthropologist G. M. Morant debated whether the two were based on the same original skull, which Digby posited was perhaps revered as a Mesoamerican "death god."

Although nearly all of the crystal skulls have at times been identified as Aztec, Toltec, Mixtec, or occasionally Maya, they do not reflect the artistic or stylistic characteristics of any of these cultures. The Aztec and Toltec versions of death heads were nearly always carved in basalt, occasionally were covered with stucco, and were probably all painted. They were usually either attached to walls or altars, or depicted in bas reliefs of deities as ornaments worn on belts. They are comparatively crudely carved, but are more naturalistic than the crystal skulls, particularly in the depiction of the teeth. The Mixtec occasionally fabricated skulls in gold, but these representations are more precisely described as skull-like faces with intact eyes, noses, and ears. The Maya also carved skulls, but in relief on limestone. Often these skulls, depicted in profile, represent days of their calendars.

French and other European buyers imagined they were buying skillful pre-Columbian carvings, partially convinced perhaps by their own fascinated horror with Aztec human sacrifice. But the Aztecs didn't hang crystal skulls around their necks. Instead, they displayed the skulls of sacrificial victims on racks, impaling them horizontally through the sides (the parietal-temporal region), not vertically.

I believe that all of the smaller crystal skulls that constitute the first generation of fakes were made in Mexico around the time they were sold, between 1856 and 1880. This 24-year period may represent the output of a single artisan, or perhaps a single workshop. The larger 1878 Paris skull seems to be some sort of transitional piece, as it follows the vertical drilling of the smaller pieces, but its size precludes it being a bead, or being worn in any way. This skull now resides in the basement laboratories of the Louvre, and the Musée du Quai Branly has begun a program of scientific testing on the piece that will include advanced elemental analysis techniques like particle induced X-ray emission and Raman spectroscopy, so we may know more about its material and age in the near future.

South American Idol?

In the opening scenes of Raiders of the Lost Ark (1981), Indiana Jones is hot on the trail of an extremely valuable golden idol created by an unidentified ancient South American culture. The goddess's image, which Jones deftly snatches from an altar (setting off a series of booby traps that culminate with an enormous boulder nearly crushing our hero), is of a woman in the act of giving birth. The golden figure was modeled on a purportedly Aztec greenstone carving called Tlazolteotl, considered to be a masterpiece by the Dumbarton Oaks Museum in Washington, D.C.

In my research into the object's acquisition history, I discovered that a Chinese dealer in Paris sold the figure in 1883 to a famous French mineralogist, Augustin Damour. His friend, Eugene Boban, advised Damour on the purchase. In examining the artifact's iconography, I found that the birthing position is unknown in documented pre-Columbian artifacts or depictions in codices. I have also used scanning electron microscopy to analyze the manufacture of the idol and have found there is ample evidence of the use of modern rotary cutting tools on the object's surface. In my opinion, the Tlazolteotl idol, like the crystal skulls, is a nineteenth-century fake.

The 1878 Paris skull and the Boban-Tiffany-British Museum skull that appeared in 1881 are perhaps nineteenth-century European inventions. There is no direct tie to Mexico for either of these two larger skulls, except through Boban; they simply appear in Paris long after his initial return from Mexico in 1869. The Mitchell-Hedges skull, which appears after 1934, is a veritable copy of the British Museum skull, with stylistic and technical flourishes that only an accomplished faker would devise. In fact, in 1936 British Museum scholar Adrian Digby first raised the possibility that the Mitchell-Hedges skull could be a copy of the British Museum skull since it showed "a perverted ingenuity such as one would expect to find in a forger." However, Digby, then a young curator, did not suggest it was a modern forgery and also dismissed the possibility that his museum's own crystal skull was a fraud, as early twentieth-century microscopic examination did not reveal the presence of modern tool marks.

The skull that arrived at the Smithsonian 16 years ago represents yet another generation of these hoaxes. According to its anonymous donor, it was purchased in Mexico in 1960, and its size perhaps reflects the exuberance of the time. In comparison with the original nineteenth-century skulls, the Smithsonian skull is enormous; at 31 pounds and nearly 10 inches high, it dwarfs all others. I believe it was probably manufactured in Mexico shortly before it was sold. (The skull is now part of the Smithsonian's national collections and even has its own catalogue number: 409954. At the moment it is stored in a locked cabinet in my office.)

There are now fifth- and probably sixth-generation skulls, and I have been asked to examine quite a number of them. Collectors have brought me skulls purportedly from Mexico, Guatemala, Brazil, and even Tibet. Some of these "crystal" skulls have turned out to be glass; a few are made of resin.

British Museum scientist Margaret Sax and I examined the British Museum and Smithsonian skulls under light and scanning electron microscope and conclusively determined that they were carved with relatively modern lapidary equipment, which were unavailable to pre-Columbian Mesoamerican carvers. (A preliminary report on our research is on the British Museum website, www.britishmuseum.ac.uk/compass). So why have crystal skulls had such a long and successful run, and why do some museums continue to exhibit them, despite their lack of archaeological context and obvious iconographic, stylistic, and technical problems? Though the British Museum exhibits its skulls as examples of fakes, others still offer them up as the genuine article. Mexico's national museum, for example, identifies its skulls as the work of Aztec and Mixtec artisans. Perhaps it is because, like the Indiana Jones movies, these macabre objects are reliable crowd-pleasers.

Impressed by their technical excellence and gleaming polish, generations of museum curators and private collectors have been taken in by these objects. But they are too good to be true. If we consider that pre-Columbian lapidaries used stone, bone, wooden, and possibly copper tools with abrasive sand to carve stone, crystal skulls are much too perfectly carved and highly polished to be believed.

Ultimately, the truth behind the skulls may have gone to the grave with Boban, a masterful dealer of many thousands of pre-Columbian artifacts--including at least five different crystal skulls--now safely ensconced in museums worldwide. He managed to confound a great many people for a very long time and has left an intriguing legacy, one that continues to puzzle us a century after his death. Boban confidently sold museums and private collectors some of the most intriguing fakes known, and perhaps many more yet to be recognized. It sounds like a great premise for a movie.

Titan: Treasures of Earth's oily twin

If worlds have shadow twins elsewhere in the Universe, then Earth's would appear to lie just a block or two down the cosmic road, in orbit around Saturn.

"We have on Titan many of the geological features that we find on Earth," enthuses Rosaly Lopes.

"We find volcanism, we find tectonics, we find erosion and deposition, and wind activity forming dunes.

"It's very similar to the Earth."

But there is a crucial difference: Titan is so cold that most of the water is solid.

This combination of liquid water in the interior plus complex organic molecules composes two big ingredients for life Ralph Lorenz, Johns Hopkins University

The rivers flowing across these plains are formed of a hydrocarbon soup with methane as its main ingredient.

The true nature of this once mysterious world is now finally emerging, courtesy largely of the Cassini-Huygens mission, a joint US-European venture, which deposited a landing craft on Titan, and continues to send back data and pictures of Saturn, its rings and its 60-odd moons.

Dr Lopes, from Nasa's Jet Propulsion Laboratory (JPL) in California, is one of the scientists reviewing the Titan findings at the European Geosciences Union (EGU) meeting in Vienna, Europe's largest annual gathering of scientists studying the Earth, its climate and its cosmic neighbourhood.

Four years after its arrival in the Saturnian system, Cassini is now showing researchers just how similar Titan is to our own planet.

Lake district

Last year, the craft's radar identified large areas close to the moon's north pole that are apparently lakes filled with the same methane-rich liquid. A few have subsequently turned up near the south pole, too.

The radar instrument has identified lakes on Titan's surface

"What you have is very much like the hydrological cycle on Earth," explains Sushil Atreya from the University of Michigan in Ann Arbor.

"We have methane lakes in the high latitude regions, and the lower part of the atmosphere is sub-saturated, so there's about 40% relative humidity [of methane].

"And from time to time, it will rain methane onto the surface, which then collects into lakes; and there are also equatorial storms in the tropical regions."

So alike do the lakes appear to those on Earth that the cosmological "nomenclature police", the International Astronomical Union (IAU), have decreed that they can be named after those on our planet.

Among others, Titan now features a Lake Abeya, a Lake Mackay and a Lake Ontario, named because their shapes resemble their terrestrial equivalents in Ethiopia, Australia and Canada.

Long trails

Perhaps the most spectacular example of Titan's mimicry of our terrestrial home lies in the river valleys, which are disturbingly Earth-like - long snaking structures with tributaries arranged like veins on a leaf.

Look at the images really hard, and you can almost imagine zooming in to find some Titanian vegetation growing along the banks, and a train of methane-guzzling animals heading down to drink.

"There are a lot of valley systems, and a few are very huge, in the order of 1,000km long," notes Ralf Jaumann from the German Aerospace Center (DLR).

Cassini has seen many valley systems on Titan's surface

"We tried to figure out what these systems are doing with erosion on the surface, and it's comparable with what we know on Earth; these rivers are doing erosion and sediment transport just as we know it from rivers like the Rhine, Elbe and probably the Mississippi. But the liquid in these rivers is not water, but methane."

Ask why methane plays the role here that water plays on Earth, and the answer is disturbingly simple: it is chance.

On Earth, water is warm enough that water is mobile, but not so warm that it evaporates into space, as would happen on Mercury. Titan is so cold - averaging about minus 180C - that water is largely frozen.

Here, it is methane that is able to flow, to evaporate, freeze, thaw and condense, without trailing away into the void.

Water bed

So if methane has usurped the role that water plays on Earth, what part is there on Titan for Earth's most important substance?

For the most part, water here is solid, behaving in some ways as rock does on Earth; a surface to be eroded, a landscape to be sculpted. But in places it emerges violently in volcanoes.

A new analysis of the moon's rotation using Cassini's radar data indicates that large quantities of liquid water may lie under the icy surface.

The Huygens probe captured images of Titan's surface features as it parachuted through the atmosphere Enlarge Image

"By matching up surface features that we saw on successive flybys, we were able to plot their positions relative to where we would have expected them to be if Titan was rotating the way it had always been expected to," explains Ralph Lorenz from Johns Hopkins University in Baltimore, US.

"In fact, on top of the expected rotation there is a little bit of a wobble back and forth that is driven by the atmosphere spinning up and spinning down with the seasons.

"Now this actually happens on Earth; the length of our day changes by about a millisecond over the course of a year. But on Titan the change is considerably more because the atmosphere is denser than ours, and Titan is a smaller body.

"The displacement of surface features that we observe is such as to require the ice crust of Titan to be comparatively thin, perhaps 100 or 200km thick, and decoupled from the core with an ocean of liquid water."

Mission life

The atmosphere of Titan has also turned out to be reminiscent of Earth's, possessing layers that mimic the troposphere, stratosphere and ionosphere above our heads.

There may be 1,000 times as much hydrocarbon as there is on Earth

In the higher levels, the interaction of solar radiation, nitrogen, and methane and other simple organic compounds leads to the formation of complex organic molecules such as benzene that later come down to the surface.

There may be 1,000 times more liquid hydrocarbons in Titan's lakes than in all the oil wells on Earth. Its dunes may hold hundreds of times the content of Earth's coal reserves.

It makes an enticing prospect for the would-be life-hunter in space.

"This combination of liquid water in the interior plus complex organic molecules composes two big ingredients for life - certainly life as we know it - and that makes Titan a very attractive body for future exploration," says Ralph Lorenz.

But Cassini is a busy craft. Its trajectory means it spends most of its time away from Titan, snapping strip-shaped radar images as it swings by the moon approximately once every month.

An ocean of liquid water may exist below Titan's surface

The first next step that scientists had been looking for was a two-year extension to Cassini's mission schedule, taking it past the original end date of July this year. As scientists were discussing the findings in Austria, Nasa officials back in Washington granted their wish.

In those two years, further flybys of Titan will mean that about 44% of the moon's surface gets mapped, as compared to 28% currently.

A further extension mission is also feasible, provided that Cassini continues to enjoy a healthy old age.

Beyond that, something dedicated to Titan is envisaged; or perhaps a "double-dip" mission taking in Titan and another of Saturn's enticing moons, Enceladus. Balloons and further landers may be deployed to sample Titan's extravagant hydrocarbon riches.

Let us hope that the craft does not navigate by vision alone. If it does, it is as likely to alight in the lake-strewn landscape of Finland or the valley of the Mississippi as on the plains of this strange and fascinating world.

Vitamin E linked to lung cancer

Vitamin E

High vitamin E doses were found to increase risk

Taking high doses of vitamin E supplements can increase the risk of lung cancer, research suggests.
The US study of 77,000 people found taking 400 milligrams per day long-term increased cancer risk by 28% - with smokers at particular risk.

It follows warnings about similar risks of excessive beta-carotene use.

Writing in the American Journal of Respiratory and Critical Care Medicine, an expert said people should get their vitamins from fruit and veg.


The jury's still very much out on whether vitamin and mineral supplements can affect cancer risk
Henry Scowcroft, Cancer Research UK

Dr Tim Byers, from the University of Colorado, said a healthy, balanced diet meant people took in a whole range of beneficial nutrients and minerals, which might help to reduce cancer risk.

The researchers followed people aged between 50 and 76 for four years and looked at their average daily use of vitamin C and folic acid, and vitamin E supplements.

Over the course of the study, 521 people developed lung cancer.

Smoking, family history and age all had unsurprisingly strong links to cancer risk.

And while neither vitamin C or folic acid use had any effect on lung cancer risk, vitamin E use did.

The researchers extrapolated their findings, and concluded that over a decade, there was an additional 7% increase in risk for every 100 milligrams taken per day.

The vitamin E trend was most prominent among smokers, but was not confined to them.

Vitamin E is known to be an antioxidant - protecting cells from molecules called free radicals.

But the US researchers speculate that, in high doses, it may also act as a pro-oxidant - causing oxidation and therefore damage to cells.

'Toxic effects'
Dr Christopher Slatore of the University of Washington in Seattle, who led the study, said: "In contrast to the often assumed benefits or at least lack of harm, supplemental vitamin E was associated with a small increased risk of lung cancer.

"Future studies may focus on other components of fruits and vegetables that may explain the decreased risk of cancer that has been associated with fruit and vegetables.

"Meanwhile, our results should prompt clinicians to counsel patients that these supplements are unlikely to reduce the risk of lung cancer and may be detrimental."

But Henry Scowcroft, senior science information officer at Cancer Research UK, said: "The jury's still very much out on whether vitamin and mineral supplements can affect cancer risk.

"Some studies suggest a benefit, but many others show no effect and some, like this one, suggest they may even increase risk."

He added: "Research repeatedly shows that a healthy, balanced diet can reduce your risk of some cancers while giving you all the vitamins you need.

"Quitting smoking remains the most effective way to avoid many cancers. There's no diet, or vitamin supplement, that could ever counter the toxic effects of cigarette smoke."

In 2002 a Finnish study of 29,000 male smokers found taking beta-carotene - which is converted into vitamin A in the body - was linked to an 18% increased risk of developing lung cancer

Vitamins 'may shorten your life'

Could they be doing more harm than good?

Research has suggested certain vitamin supplements do not extend life and could even lead to a premature death.

A review of 67 studies found "no convincing evidence" that antioxidant supplements cut the risk of dying.

Scientists at Copenhagen University said vitamins A and E could interfere with the body's natural defences.

"Even more, beta-carotene, vitamin A, and vitamin E seem to increase mortality," according to the review by the respected Cochrane Collaboration.

The research involved selecting various studies from 817 on beta-carotene, vitamin A, vitamin C, vitamin E, and selenium which the team felt were the most likely to fairly reflect the impact of the supplements on reducing mortality.

It has been thought that these supplements may be able to prevent damage to the body's tissues called "oxidative stress" by eliminating the molecules called "free radicals" which are said to cause it.

This damage has been implicated in several major diseases including cancer and heart disease.

'Just eat well'

The trials involved 233,000 people who were either sick or were healthy and taking supplements for disease prevention.

VITAL VITAMIN FACTS Vitamin A: Found in: Oily fish, eggs and liver; Good for: Thought to boost immune system, and help skin, sight and sperm formation Vitamin C: Found in: Many fruit and vegetables; Good for: Helps heal wounds and assists the body in absorbing iron, may boost the immune system Vitamin E: Found in: Vegetable oils, seeds and nuts; Good for: May help boost circulation and keep elderly people active Beta-carotene: Found in: Vegetables that are reddish-orange in colour; Good for: May boost vision and keep the mind sharp Selenium: Found in: Butter, nuts, liver and fish; Good for: May boost the immune system How many take vitamins? Between 10-20% of people in the West How much is the global market worth? About $2.5bn (£1.3bn)

After various factors were taken into account and a further 20 studies excluded, the researchers linked vitamin A supplements to a 16% increased risk of dying, beta-carotene to a 7% increased risk and vitamin E to a 4% increased risk.

Vitamin C did not appear to have any effect one way or the other, and the team said more work was needed into this supplement - as well as into selenium.

In conclusion, "we found no evidence to support antioxidant supplements for primary or secondary prevention," they said.

It was unclear exactly why the supplements could have this effect, but the team speculated that they could interfere with how the body works: beta-carotene, for instance, is thought to change the way a body uses fats.

The Department of Health said people should try to get the vitamins they need from their diet, and avoid taking large doses of supplements - a market which is worth over £330m in the UK.

"There is a need to exercise caution in the use of high doses of purified supplements of vitamins, including antioxidant vitamins, and minerals," a spokesperson said.

"Their impact on long-term health may not have been fully established and they cannot be assumed to be without risk."

A 'stitch-up'

But the Health Supplements Information Service, which is funded by the association which represents those who sell supplements, said many people were simply not able to get everything they needed from their diet.

Dr Rosemary Leonard's advice on vitamins

"For the millions who are not able to do that, vitamins can be a useful supplement and they should not stop taking them," said spokeswoman Pamela Mason.

Another nutritionist who has formulated supplements described the review as a "stitch-up", arguing it only looked at studies which examined the effect they had on reducing mortality, rather than other advantages.

"Antioxidants are not meant to be magic bullets and should not be expected to undo a lifetime of unhealthy habits," said Patrick Holford.

"But when used properly, in combination with eating a healthy diet full of fruit and vegetables, getting plenty of exercise and not smoking, antioxidant supplements can play an important role in maintaining and promoting overall health."

Vitamin supplements help and are not a substitute -Joel Kosminsky, London