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Ancient Roman Glue Sticks Around

Glued With Care
Glued With Care
The silver laurel leaves on this ancient Roman helmet were glued to the piece of armor with a fixative that has survived for thousands of years. Scientists studying the glue have found it was made of a mixture of bark and animal grease.

Roman warriors repaired their battle accessories with a superglue that is still sticking around after 2,000 years, according to new findings on display at the Rheinischen Landes Museum in Bonn, Germany.

Running until Feb. 16, 2008, the exhibition "Behind the Silver Mask" presents evidence that the ancient adhesive was used to mount silver laurel leaves on legionnaires' battle helmets.

"It's a sensational find and a complete stroke of luck that we were still able to find traces of the substance after 2000 years," Frank Willer, the museum's chief restorer, told Discovery News.

Willer found traces of the superglue while examining a helmet unearthed in 1986 near the German town of Xanten, on what was once the bed of the Rhine.

"The helmet, which dates from the 1st century B.C., was given to the museum for restoration. I discovered the glue accidentally, while removing a tiny sample of metal from the helmet with a fine saw. The heat from the tool caused the silver laurel leaves on the helmet to peel off, leaving thread-like traces of the glue behind," Willer said.

Willer was amazed to discover that despite such a long exposure to water, time and air, the superglue did not lose its bonding properties.

He said that other Roman battle accessories kept by the museum have traces of silver decorations which most likely had been glued to the iron with the same adhesive and technique. Unfortunately, the objects are too deteriorated to find traces of the superglue.

However, the helmet unearthed at Xanten featured enough material to determine how the adhesive was made.

"Analysis shows that the Roman glue was made of bitumen, bark pitch and animal grease," Willer said.

The finding confirms studies done by researchers at the University of Bradford and Liverpool, U.K., in the 1990s.

Analysis carried at that time on an ancient Roman jar showed that when Roman people broke their pots, they glued them back together with a compund "derived largely from birch bark."

So far, the German researchers have failed to recreate the Roman superglue.

"We think that some inorganic material such as soot, sand and quartz, might have been added to make the mixture stickier," Willer said.

PR

Our Decrepit Food Factories

 

The word “sustainability” has gotten such a workout lately that the whole concept is in danger of floating away on a sea of inoffensiveness. Everybody, it seems, is for it whatever “it” means. On a recent visit to a land-grant university’s spanking-new sustainability institute, I asked my host how many of the school’s faculty members were involved. She beamed: When letters went out asking who on campus was doing research that might fit under that rubric, virtually everyone replied in the affirmative. What a nice surprise, she suggested. But really, what soul working in agricultural science today (or for that matter in any other field of endeavor) would stand up and be counted as against sustainability? When pesticide makers and genetic engineers cloak themselves in the term, you have to wonder if we haven’t succeeded in defining sustainability down, to paraphrase the late Senator Moynihan, and if it will soon possess all the conceptual force of a word like “natural” or “green” or “nice.”

Confucius advised that if we hoped to repair what was wrong in the world, we had best start with the “rectification of the names.” The corruption of society begins with the failure to call things by their proper names, he maintained, and its renovation begins with the reattachment of words to real things and precise concepts. So what about this much-abused pair of names, sustainable and unsustainable?

To call a practice or system unsustainable is not just to lodge an objection based on aesthetics, say, or fairness or some ideal of environmental rectitude. What it means is that the practice or process can’t go on indefinitely because it is destroying the very conditions on which it depends. It means that, as the Marxists used to say, there are internal contradictions that sooner or later will lead to a breakdown.

For years now, critics have been speaking of modern industrial agriculture as “unsustainable” in precisely these terms, though what form the “breakdown” might take or when it might happen has never been certain. Would the aquifers run dry? The pesticides stop working? The soil lose its fertility? All these breakdowns have been predicted and they may yet come to pass. But if a system is unsustainable — if its workings offend the rules of nature — the cracks and signs of breakdown may show up in the most unexpected times and places. Two stories in the news this year, stories that on their faces would seem to have nothing to do with each other let alone with agriculture, may point to an imminent breakdown in the way we’re growing food today.

The first story is about MRSA, the very scary antibiotic-resistant strain of Staphylococcus bacteria that is now killing more Americans each year than AIDS — 100,000 infections leading to 19,000 deaths in 2005, according to estimates in The Journal of the American Medical Association. For years now, drug-resistant staph infections have been a problem in hospitals, where the heavy use of antibiotics can create resistant strains of bacteria. It’s Evolution 101: the drugs kill off all but the tiny handful of microbes that, by dint of a chance mutation, possess genes allowing them to withstand the onslaught; these hardy survivors then get to work building a drug-resistant superrace. The methicillin-resistant staph that first emerged in hospitals as early as the 1960s posed a threat mostly to elderly patients. But a new and even more virulent strain — called “community-acquired MRSA” — is now killing young and otherwise healthy people who have not set foot in a hospital. No one is yet sure how or where this strain evolved, but it is sufficiently different from the hospital-bred strains to have some researchers looking elsewhere for its origin, to another environment where the heavy use of antibiotics is selecting for the evolution of a lethal new microbe: the concentrated animal feeding operation, or CAFO.

The Union of Concerned Scientists estimates that at least 70 percent of the antibiotics used in America are fed to animals living on factory farms. Raising vast numbers of pigs or chickens or cattle in close and filthy confinement simply would not be possible without the routine feeding of antibiotics to keep the animals from dying of infectious diseases. That the antibiotics speed up the animals’ growth also commends their use to industrial agriculture, but the crucial fact is that without these pharmaceuticals, meat production practiced on the scale and with the intensity we practice it could not be sustained for months, let alone decades.

Public-health experts have been warning us for years that this situation is a public-health disaster waiting to happen. Sooner or later, the profligate use of these antibiotics — in many cases the very same ones we depend on when we’re sick — would lead to the evolution of bacteria that could shake them off like a spring shower. It appears that “sooner or later” may be now. Recent studies in Europe and Canada found that confinement pig operations have become reservoirs of MRSA. A European study found that 60 percent of pig farms that routinely used antibiotics had MRSA-positive pigs (compared with 5 percent of farms that did not feed pigs antibiotics). This month, the Centers for Disease Control and Prevention published a study showing that a strain of “MRSA from an animal reservoir has recently entered the human population and is now responsible for [more than] 20 percent of all MRSA in the Netherlands.” Is this strictly a European problem? Evidently not. According to a study in Veterinary Microbiology, MRSA was found on 45 percent of the 20 pig farms sampled in Ontario, and in 20 percent of the pig farmers. (People can harbor the bacteria without being infected by it.) Thanks to Nafta, pigs move freely between Canada and the United States. So MRSA may be present on American pig farms; we just haven’t looked yet.

Scientists have not established that any of the strains of MRSA presently killing Americans originated on factory farms. But given the rising public alarm about MRSA and the widespread use on these farms of precisely the class of antibiotics to which these microbes have acquired resistance, you would think our public-health authorities would be all over it. Apparently not. When, in August, the Keep Antibiotics Working coalition asked the Food and Drug Administration what the agency was doing about the problem of MRSA in livestock, the agency had little to say. Earlier this month, though, the F.D.A. indicated that it may begin a pilot screening program with the C.D.C.

As for independent public-health researchers, they say they can’t study the problem without the cooperation of the livestock industry, which, not surprisingly, has not been forthcoming. For what if these researchers should find proof that one of the hidden costs of cheap meat is an epidemic of drug-resistant infection among young people? There would be calls to revolutionize the way we produce meat in this country. This is not something that the meat and the pharmaceutical industries or their respective regulatory “watchdogs” — the Department of Agriculture and F.D.A. — are in any rush to see happen.

he second story is about honeybees, which have endured their own mysterious epidemic this past year. Colony Collapse Disorder was first identified in 2006, when a Pennsylvanian beekeeper noticed that his bees were disappearing — going out on foraging expeditions in the morning never to return. Within months, beekeepers in 24 states were reporting losses of between 20 percent and 80 percent of their bees, in some cases virtually overnight. Entomologists have yet to identify the culprit, but suspects include a virus, agricultural pesticides and a parasitic mite. (Media reports that genetically modified crops or cellphone towers might be responsible have been discounted.) But whatever turns out to be the immediate cause of colony collapse, many entomologists believe some such disaster was waiting to happen: the lifestyle of the modern honeybee leaves the insects so stressed out and their immune systems so compromised that, much like livestock on factory farms, they’ve become vulnerable to whatever new infectious agent happens to come along.

You need look no farther than a California almond orchard to understand how these bees, which have become indispensable workers in the vast fields of industrial agriculture, could have gotten into such trouble. Like a great many other food crops, like an estimated one out of every three bites you eat, the almond depends on bees for pollination. No bees, no almonds. The problem is that almonds today are grown in such vast monocultures — 80 percent of the world’s crop comes from a 600,000-acre swath of orchard in California’s Central Valley — that, when the trees come into bloom for three weeks every February, there are simply not enough bees in the valley to pollinate all those flowers. For what bee would hang around an orchard where there’s absolutely nothing to eat for the 49 weeks of the year that the almond trees aren’t in bloom? So every February the almond growers must import an army of migrant honeybees to the Central Valley — more than a million hives housing as many as 40 billion bees in all.

They come on the backs of tractor-trailers from as far away as New England. These days, more than half of all the beehives in America are on the move to California every February, for what has been called the world’s greatest “pollination event.” (Be there!) Bees that have been dormant in the depths of a Minnesota winter are woken up to go to work in the California spring; to get them in shape to travel cross-country and wade into the vast orgy of almond bloom, their keepers ply them with “pollen patties” — which often include ingredients like high-fructose corn syrup and flower pollen imported from China. Because the pollination is so critical and the bee population so depleted, almond growers will pay up to $150 to rent a box of bees for three weeks, creating a multimillion-dollar industry of migrant beekeeping that barely existed a few decades ago. Thirty-five years ago you could rent a box of bees for $10. (Pimping bees is the whole of the almond business for these beekeepers since almond honey is so bitter as to be worthless.)

In 2005 the demand for honeybees in California had so far outstripped supply that the U.S.D.A. approved the importation of bees from Australia. These bees get off a 747 at SFO and travel by truck to the Central Valley, where they get to work pollinating almond flowers — and mingling with bees arriving from every corner of America. As one beekeeper put it to Singeli Agnew in The San Francisco Chronicle, California’s almond orchards have become “one big brothel” — a place where each February bees swap microbes and parasites from all over the country and the world before returning home bearing whatever pathogens they may have picked up. Add to this their routine exposure to agricultural pesticides and you have a bee population ripe for an epidemic national in scope. In October, the journal Science published a study that implicated a virus (Israeli Acute Paralysis Virus) in Colony Collapse Disorder — a virus that was found in some of the bees from Australia. (The following month, the U.S.D.A. questioned the study, pointing out that the virus was present in North America as early as 2002.)

“We’re placing so many demands on bees we’re forgetting that they’re a living organism and that they have a seasonal life cycle,” Marla Spivak, a honeybee entomologist at the University of Minnesota, told The Chronicle. “We’re wanting them to function as a machine. . . . We’re expecting them to get off the truck and be fine.”

We’re asking a lot of our bees. We’re asking a lot of our pigs too. That seems to be a hallmark of industrial agriculture: to maximize production and keep food as cheap as possible, it pushes natural systems and organisms to their limit, asking them to function as efficiently as machines. When the inevitable problems crop up — when bees or pigs remind us they are not machines — the system can be ingenious in finding “solutions,” whether in the form of antibiotics to keep pigs healthy or foreign bees to help pollinate the almonds. But this year’s solutions have a way of becoming next year’s problems. That is to say, they aren’t “sustainable.”

From this perspective, the story of Colony Collapse Disorder and the story of drug-resistant staph are the same story. Both are parables about the precariousness of monocultures. Whenever we try to rearrange natural systems along the lines of a machine or a factory, whether by raising too many pigs in one place or too many almond trees, whatever we may gain in industrial efficiency, we sacrifice in biological resilience. The question is not whether systems this brittle will break down, but when and how, and whether when they do, we’ll be prepared to treat the whole idea of sustainability as something more than a nice word.

Absinthe Terms

 

WORMWOOD, Artemisia absinthium, is shown in James Sowerby’s 1803 handcolored engraving. Oil of wormwood was extracted from the herb’s leaves, flowers and stem; it gave absinthe a distinctively bitter taste. Wormwood oil includes thujone, which can cause hallucinations, convulsions and permanent damage to the nervous system.

DILUTION of the alcohol concentration of absinthe caused precipitation of a colloidal suspension of terpenes, of which thujone is one. The ritual of presentation involved pouring cold water over a sugar cube placed on a slotted spoon. (Sugar took the edge off the liqueur’s bitterness.) One can get the same visual effect by diluting today’s nontoxic substitute, pastis; the author did this demonstration with Pernod.

Large steam-heated stills such as the pair shown were used In the production of absinthe during the second half of the 19th century. An 1855 recipe from Pontarlier, France, gives the following Instructions for making absinthe: Macerate 2.5 kilograms of dried wormwood, 5 kilograms of anise and 5 kilograms of fennel in 95 liters of 85 percent ethanol by volume. Let the mixture steep for at least 12 hours. In the pot of a double boiler, add 45 liters of water and apply heat; collect 95 liters of distillate. To 40 liters of the distillate, add 1 kilogram of Roman wormwood, 1 kilogram of hyssop and 500 grams of lemon balm, all of which have been dried and finely divided. Extract at a moderate temperature, then siphon off the liquor, filter and reunite it with the remaining 55 liters of distillate. Dilute with water to produce approximately 100 liters of absinthe with a final alcohol concentration of 74 percent by volume.    

COMPOUNDS IN ABSINTHE include several terpenes: thujone (from wormwood), pinocamphone (from hyssop) and fenchone (from fennel). These compounds are ketones and structural isomers of camphor (C10H16O). The aliphatic aldehyde citral (C10H16O), which is also a terpene, comes from melissa. Fennel and anise also contribute an aromatic ether called anethole (C10H12O). The carbon atoms in this illustration are black and the oxygen atoms, red; hydrogen atoms are not shown.

The concentration of ethanol in spirits is customarily expressed as a percentage or a proof value. A 70 percent solution by volume consists of 70 volumes of pure ethanol brought to 100 volumes of solution by the addition of water; because of the interaction between ethanol molecules and water molecules, 33.4 volumes of water, rather than 30, must be added. The most practical means of determining the alcohol concentrations of commercial spirits is the alcoholometer shown here, a device perfected in 1824 by Joseph-Louis Gay-Lussac. The meter measures the specific gravity of a distillate; it is floated in a sample at a prescribed temperature, and the depth to which it sinks indicates the percentage of alcohol in the solution. Percentage or proof value can be read directly from the scales inscribed on its stem. When absinthe was popular, alcohol concentration was expressed in the old French system of degrees, which were numerically equivalent to percentages by volume. The British coined the term “proof"; their proof spirit, which corresponded to 57.27 percent ethanol by volume, was operationally defined as one having the maximum concentration of water that would still allow ignition after admixture with gunpowder. In the U.S. the term was modified; the proof value is exactly double the percent by volume, so that a liquor that is 50 percent ethanol by volume is defined as 100 proof. 

IEA ups forecast for 2008 world oil demand by 115,000 bpd
A motorist holds a fuel pump at a petrol station in Tehran. ...
A motorist holds a fuel pump at a petrol station in Tehran. The International Energy Agency has raised its forecast for world oil demand for next year by 115,000 barrels per day because of demand from emerging economies.

The International Energy Agency on Friday raised its forecast for world oil demand for next year by 115,000 barrels per day because of demand from emerging economies.

But the agency, the developed world's energy watchdog, in its monthly Oil Market Report lowered its 2007 world oil demand forecast due to lower-than-expected heating fuel consumption in North America and in Europe.

The IEA's monthly report also said that supply-demand balances for winter have "clearly improved" but warned that the market was still nervous, as indicated by oil prices, which are still around 90 dollars a barrel.

"90 dollars a barrel oil makes clear that the market is still on edge and is unlikely to relax until the peak weather risks have subsided and a clear trend in OPEC supplies is apparent," the report said.

For 2007, the IEA now sees world oil product demand amounting to 85.7 million barrrels per day (bpd), a downward revision of 60,000 bpd for the previous month's estimate.

For 2008, however, the agency has revised up its oil demand forecast. It now sees total demand of 87.8 million bpd, an upward revision of 115,000 bpd.

This is due mainly to increased demand from emerging economies, notably Saudi Arabia, as well as expectations of a normal winter after the exceptionally mild northern hemispehere winter this year.

The IEA, which represents mostly western, oil consuming nations, said high oil prices were beginning to squeeze demand in Europe and North America. But at the same time, global supply has begun improving, it said.

While the recent decision by the Organisation of the Petroleum Exporting Countries (OPEC) cartel to keep output quotas steady surprised the market, it had to be viewed in terms of what is happening on the ground.

Output from the 10 OPEC members bound by quotas rose by 400,000 bpd in September, reaching target levels of 27.3 million bpd in October.

In November, however, field maintenance in the United Arab Emirates prompted a dip in OPEC 10 output to 27.1 million bpd.

But this dip was overshadowed by 330,000 bpd increase in Iraqi output between August and November, and an increase of 70,000 bpd in Angolan output.

In addition, world oil supply also rose in November, climbing by 55,000 bpd to 86.5 million on a recovery in Mexican, Chinese and Brazilian output.

"Overall, winter prospects have clearly improved," said the IEA.

There is still a risk demand could peak if winter temperatures plummet. Meanwhile, there is as yet no clear trend in OPEC supplies, which remain relatively unpredictable.

Moreover, stocks in the industrialised countries which are members of the Organisation for Economic Cooperation and Development (OECD) are still on a downward trend, said the IEA's December report.

They fell by 22.4 million bpd in October, lowering demand cover to 52.6 days -- just below the 5-year average.

"Of course, declining stocks are normal in the winter, but at present levels the market is likely to respond quickly if the currently higher OPEC supplies drop off," said the IEA.

Stellar Opposites: Sky survey reveals new halo of stars

The Milky Way galaxy possesses a distinct outer halo that orbits in the opposite direction from its inner halo and the rest of the galaxy, researchers say. This second halo contains some of the most primitive stars in the universe, offering new evidence about how the galaxy formed.

Some scientists had previously suspected that a portion of the stars in the Milky Way travel in a different direction from the rest. But data on such stars were too sparse to conclude that an entire second halo existed.

Now, an international team of scientists including Timothy Beers of Michigan State University in East Lansing has discovered stronger evidence for a double halo. Beers and his colleagues analyzed more than 20,000 stars as part of the Sloan Digital Sky Survey, an astronomical effort to create a three-dimensional map of about a million galaxies.

The scientists noticed that stars more than 50,000 light-years away from the center of the Milky Way move in the opposite direction from closer ones, have distinctive chemical compositions, and travel around the galaxy at different speeds.

"It was certainly a surprise to my team how well the two populations were resolved from one another with the new data," says Beers.

Stars in the Milky Way's inner disk, where the Earth is located, orbit at 200 kilometers per second (kps). The inner halo moves in the same direction as this disk, but at 25 kps. Stars in the outer halo appear to speed around the galaxy in the opposite direction at about 50 kps.

Beers observes that the existence of small, metal-poor stars in the outer halo suggests a new story of the evolution of the galaxy.

The dense central region of the galaxy and the inner halo that surrounds it probably formed first, says Beers, as heavy, metal-rich stars clumped together to create the Milky Way. Dwarflike galaxies left behind merged together later to create the outer halo, he hypothesizes.

Though this halo formed after the inner halo, its stars are deficient in heavy metals, implying that they are older. These stars likely formed from gas that existed early in the universe, before all elements existed plentifully, says Beers.

The new findings, which appear in the Dec. 13 Nature, do not alter the inference that an invisible form of dark matter occupies the galaxy's halo region, Beers says. The stars in both halos are so far away from the center of the galaxy that their orbital velocity requires more gravity than visible matter supplies.

Rosie Wyse of Johns Hopkins University in Baltimore says the new data provide compelling statistical evidence in support of a distinct outer halo of the Milky Way. But she says questions remain about the nature and formation of the halo.

For example, the Milky Way's central bulge contains stars as old as those identified in the outer halo. Wyse says scientists must understand the relationship between this bulge and the outer halo to tell the full history of the galaxy.

"We need future, large, dedicated spectroscopic surveys of stars in our galaxy to answer the many outstanding questions," she says. 

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