Monday, January 26, 2004

Iran's Salt Glaciers Click here to view full image (231 kb) In southern Iran, the collision between the Asian landmass and the Arabian platform has folded rocks and pushed up the rugged Zagros Mountains. In places, underlying deposits of salt have ascended in fluid-like plumes. Some of these plumes have pushed through the rock above, like toothpaste from a tube, and they are now visible as darkish irregular patches. This image shows a few of over 200 similar features—called diapirs, or salt plugs—that are scattered about this part of the Zagros Mountains. Gravity has caused the salt to flow like glaciers into adjacent valleys. The resulting tongue-shaped bodies are more than 5 kilometers long, with repeating bow-shaped ridges separated by crevasse-like gullies and with steep sides and fronts. The darker tones are due to clays brought up with the salt, as well as the probable accumulation of airborne dust. This ASTER perspective view was created by draping a band 3-2-1 (RGB) image over an ASTER-derived Digital Elevation Model (2x vertical exaggeration), and was acquired on August 10, 2001. 7:27:07 PM    comment []

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FINALLY, NTOICE IS BEING TAKEN... Migration of Skilled Jobs Abroad Unsettles Global-Economy Fans By BOB DAVIS Staff Reporter of THE WALL STREET JOURNAL DAVOS, Switzerland -- Many of the business, government and academic leaders who came here for the annual meeting of the World Economic Forum, traditionally a gathering of advocates of globalization, have voiced doubts over the past few days about one of the central tenets of global economic integration. They question whether the increasingly global economy will produce as many high-wage jobs in rich countries as once was expected. Their concern stems from the free-trade axiom that when a rich country sends blue-collar jobs overseas, it creates opportunities back home for workers to move up the skill ladder. The more recent corollary was that sending service jobs overseas would do the same for white-collar workers back home. But the rising number of skilled, white-collar jobs migrating from rich nations to developing countries is raising fears that, in fact, well-paid workers in developed countries will have trouble finding equally well-paid computer, design and medical jobs at home. Many of the true believers in globalization at the Davos forum, which ended Sunday, worry that outsourcing also could erode political support for free trade internationally. "When auto-manufacturing jobs went to Mexico, we said we'd push the bar up and create better jobs," said William Daley, who guided the North American Free Trade Agreement through Congress for former President Clinton and is president of SBC Communications Inc., a San Antonio, Texas, telecommunications operator. "Can you keep going up the job chain?" Zhu Min, general manager of the state-owned Bank of China, suggested that the U.S. does need "to reposition itself. Manufacturing is gone; services are going. Research and development is still there. [The U.S.] needs to move up the [development] chain." Others noted that there are substantial differences between how trade affects workers in manufacturing and services. In developed countries, lofty tariff barriers to imported goods had to be whittled away before many manufacturing jobs were at risk, a process that took decades. Governments could limit the losses by reimposing tariffs. High import tariffs eliminate some of the economic argument for using lower-cost labor abroad to make goods that will be more costly as U.S. imports under those tariffs. But service trade isn't affected much by tariffs, and can move as rapidly as the improvements in computers and communications allow. Therefore, the job loss can be more sudden. Alarm Is Sounded So long as manufacturing jobs were at stake, opinion leaders didn't take much note, said Dani Rodrik, a Harvard University economist. The alarm is being sounded now, he said, because "the opinion leaders are seeing their neighbors being displaced." Many economists at Davos said the fears over outsourcing were overblown. If Indian programmers, for instance, produce software at lower prices than Americans can, that would reduce costs for the many users of information technology. As that lower-price software permeates U.S. and European companies, those companies would become more productive and more able to hire new workers. At the same time, as India and China develop economically, they would become more-lucrative markets for U.S. exports. While the number of U.S. service workers whose jobs have been outsourced is small -- estimates range from 250,000 to 500,000 during the past three years -- the potential for further job loss is immense, all sides at Davos agreed. Brendan Barber, secretary-general of Trade Union Congress, a British labor confederation, estimated that two million service jobs could be outsourced from wealthy nations in the next five years. In the U.S., outsourcing is increasingly becoming a political issue. Sen. John Kerry of Massachusetts, a Democratic presidential contender, is looking at tax-law changes to discourage shifting jobs abroad and requiring workers in call centers to identify the nation in which they are located. About a dozen states also are looking at putting curbs on the use of outsourcing in government contracts. Democratic Rep. Barney Frank of Massachusetts, among several U.S. politicians at Davos this year, said the issue could hurt President Bush in Ohio and other Midwestern states. Mr. Bush's commerce secretary, Donald Evans, challenged that, saying the jobs lost so far involve "pretty small numbers." Some of the beneficiaries of outsourcing outside the U.S. keep a wary eye on Washington. A provision in the massive spending bill Congress passed last week, though little-noticed in the U.S. media, is stirring up a storm in India, where it is seen as evidence of a backlash that will slow outsourcing. The law says that when the federal government decides to allow private companies to do work now being done by government employees, the private companies can't do the work outside the U.S. (The provision doesn't apply to work the government employees themselves were doing outside the country.) For the past few decades, U.S. presidents have sold free trade and global integration as an economic-development strategy. Although the U.S. would lose some manufacturing jobs to developing nations where labor costs are lower, the argument went, the U.S. would gain higher-paying, higher-skilled jobs that poor nations were unable to master. Outsourcing makes that argument less compelling. Through technology that makes communication quicker and less expensive and education that is creating pools of skilled workers in some developing countries, U.S. companies now do work abroad that once had been reserved for the U.S., Western Europe and Japan. Software programming has been outsourced for years to India. Low-paying jobs in call centers also have been shifted to English-speaking countries around the globe. Now high-end computer-systems integration is leaving the U.S., too, as is architectural and design work. As reported last week, International Business Machines Corp., Armonk, N.Y., plans to shift about 3,000 high-paying programming jobs to China, India and Brazil from the U.S. (See article.) Lower-Priced Research Talent An official at Davos from an Indian company boasted that the company could develop drugs for far less than the U.S. and Europe could -- because of lower-priced research talent and bargain rates to run large-scale drug tests. "We cannot protect the American people from reality," said Hewlett-Packard Co. Chief Executive Carly Fiorina, speaking at Davos. "There are many, many qualified engineers around the world who want to participate" in advanced research. Catherine Mann, an analyst at the Institute of International Economics in Washington, has estimated that U.S. companies were able to reduce the cost of computers and communications equipment by about 10% to 30% by making the equipment in factories around the world. That lifted U.S. economic growth by about 0.3 percentage point a year between 1995 and 2002, as more companies made use of information technology. She expects similar economic gains if computer software is produced in an internationally efficient fashion. 7:02:51 PM    comment []

BE CAREFUL OUT THERE: Major E-Mail Virus Is Wreaking Havoc By RIVA RICHMOND DOW JONES NEWSWIRES NEW YORK -- An e-mail virus is running rampant through the Internet, infecting a host of large corporations and generating an avalanche of e-mail, thanks to a novel use of both virus and spamming tactics. The virus, dubbed "Mydoom" by antivirus software maker Network Associates Inc. and "Novarg" by rival Symantec Corp., struck just after 4 p.m. EST. It's creating an outbreak experts expect to be larger than that of any other recent e-mail virus, including those in the "Mimail" and "SoBig" families of viruses. "It's something of the likes of which we've never seen before because of the way that it's spreading," said Vincent Gullotto, vice president of Network Associates' Antivirus Emergency Response Team. Two of the company's customers reported that 1,000 e-mails per minute were hitting their e-mail gateways, he said, and at least four Fortune 500 companies have reported infection. Such victims can quickly advance a virus, such as Mydoom/Novarg, that harnesses internal e-mail lists because their internal address books are enormous. Sharon Ruckman, senior director of Symantec Security Response, said the outbreak, already massive in its first hour of existence, looks like it will be comparable to the terrible "Nimda" outbreak of September 2001. The Nimda virus infected personal computers and servers running various versions of Windows operating systems. The worm spread itself via e-mail, Web browsers and corporate networks. It clogged servers and slowed traffic on many corporate networks, and infected thousands of home PCs. The worm was designed to resend itself every 10 days if it wasn't deleted. In addition, it could turn computers into zombies that could be used to launch future denial-of-service attacks on Web sites. Write to Riva Richmond at riva.richmond@dowjones.com 6:57:28 PM    comment []

Microsoft: XML patent moves are no big deal Last modified: January 26, 2004, 3:56 PM PST By David Becker Staff Writer, CNET News.com         Recent patent applications filed by Microsoft are routine moves and don't reflect a change in the company's position on Extensible Markup Language, according to a spokesman for the software maker. As previously reported, Microsoft has filed applications for numerous XML-related patents in the United States, Europe and New Zealand. The patents deal with the way its Office software processes XML, the fast-growing standard for exchanging data among disparate computing systems. XML-based capabilities have been one of the main selling points for Office 2003, the recently released version of Microsoft's market-leading productivity package. By saving documents as XML files, Office allows back-end computing systems, such as corporate databases, to retrieve and reuse data from those documents. XML support also allows Office to become a client for viewing and manipulating data from Web services and from complex enterprise applications such as customer relationship management (CRM) software. Analysts said some of the proposed patents could prevent competing applications from opening XML files created in Office. "This is a direct challenge to software vendors who want to interoperate with Word through XML," according to Rob Helm, of research firm Directions on Microsoft. "For example, if Corel wanted to improve WordPerfect's support of Word by adopting its XML format...for import/export, they'd probably have to license this patent." Microsoft spokesman Mark Martin said the company couldn't comment on how the patents, if granted, might be applied or licensed. But he said such applications are standard moves for the company to protect its innovations and don't affect its commitment to openly sharing the XML schemas used by Office. "While the XML standard itself is royalty-free, nothing precludes a company from seeking patent protection for a specific software implementation that incorporates elements of XML," Martin said. "The presence of this patent application...does nothing to change the commitment Microsoft made this past November when it announced the available of a royalty-free licensing program for our Office 2003 XML reference schemas." Martin added that numerous technology companies have sought XML-related patents. A search of the U.S. Patent and Trademark Office shows hundreds of applications for patents related to the processing of XML code. "This is an industry-standard means of differentiation followed by other major companies," Martin said. 6:50:39 PM    comment []

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I AM GOING TO BE AT THE AIPLA WINTER MEETINGS IN CALIFORNIA LATER THIS WEEK SO I WILL NOT BE ABLE TO POST.  PALM SPRINGS IS A DECADENT, INDULGENT PLACE BUT IT IS A LOT WARMER THAN MINNESOTA.  ALSO, I NEED TO CLE'S.  5:54:49 PM    comment []

Magic eyes New Scientist vol 181 issue 2431 - 24 January 2004, page 24   They look like simple slabs of rubber or plastic. Yet they bend light like a lens - and change their focus at the flick of a switch. Jeff Hecht investigates a new kind of optics, and why the Pentagon is so interested   THE lens in Ed Rietman's lab looks like something a basement inventor put together at home. It consists of a circular slab of transparent rubber a little smaller than a jam-jar lid, held in an aluminium frame. Light seems to pass through it in just the same way as through any other transparent material. And the view through the lens is nothing special, just a power cable on the other side of the office. It is hard to believe that something so modest-looking could change optics for ever. But when Rietman switches on the power to his lens, something strange happens. The flat slab of rubber doesn't move, change shape or rotate as a more conventional lens might, but the view through it changes dramatically. Suddenly, the cable on the other side of the room shrinks. When Rietman turns off the power, the view returns to normal. Not only is his rubber slab acting as a lens, it is also changing its power. Rietman's work is one of a number of projects commissioned by the US Defense Advanced Projects Research Agency aimed at developing a revolutionary new family of lenses. The programme is the brainchild of Len Buckley, a chemist from the Naval Research Laboratory in Washington DC. The lenses Buckley is aiming for could change everything from high-powered telescopes and military guidance systems to cheap disposable cameras. "If you look at what's been done with lenses over the past several hundred years, it hasn't changed very much," Buckley says. As he prepared to join DARPA in early 2002, Buckley began to think about ways to move on from this medieval technology. DARPA asks incoming project managers to plan fresh approaches to important technical problems, and Buckley decided to tackle the complexity of modern optical systems. Periscopes, viewfinders, telescopes and camera lenses are made up of many individual optical components. They are masterpieces of ingenuity, but they are also cumbersome and delicate. Zoom lenses in particular can be extremely unwieldy compared to the size of the camera. Designers have wrestled for decades over the problem of how to reduce this complexity and bulk while maintaining high performance. But Buckley has a new approach that he hopes will change everything. The key property of any material used to make lenses - apart, of course, from its transparency - is the ability to bend light. The strength of this bending effect is summed up in a parameter known as its refractive index, which is essentially a measure of how much more slowly light moves through the material compared with its speed in a vacuum. For example, the glass used in conventional camera lenses is said to have a refractive index of 1.5, because light travels 1.5 times as fast in a vacuum as it does in the glass. It is the change in speed as a light ray crosses the boundary between one material and another that causes its path to bend. The amount by which the ray bends depends on the angle at which it crosses the boundary, so the optical behaviour of a conventional lens is fixed by its shape. If a lens is convex, meaning thicker at the middle than at the sides, parallel light rays are bent so that they come together, like sunlight focused by a magnifying glass. If the lens is concave, or thicker at the sides, the light rays are spread apart. In modern cameras, images are projected onto photographic film or electronic imaging chips by assembling two or more lenses and moving them back and forth to keep the image in focus. The limit to how much a lens or system of lenses can be moved in a camera or microscope restricts the range of distances an optical system can cope with. It can be extended with extra lenses and clever design, and part of the lens designer's art is to balance this complexity against cost and practicality. But Buckley knew another way. The human eye has only one lens, yet it does a superb job of focusing on objects over a range of distances. Instead of moving, the eye's lens focuses by changing its shape. Turn from this page to look far away, and the lens of your eye becomes thinner and flatter to keep the image in focus. Turn your gaze back to the page, and your lens becomes rounder and fatter again. This got Buckley thinking about another way of changing the power of a lens: not by changing its shape, but by changing the refractive index at different distances throughout the lens. Buckley knew that in some materials, such as certain silicones, the refractive index can be changed, just slightly, by passing ultrasonic pressure waves through them. As the waves interact with the material, they push atoms together then pull them apart, making the material alternately denser and less dense. This produces a moving pattern of alternating zones of high and low refractive index as the waves pass through the material. The ability of ultrasonic waves in solids to modulate a beam of light and make it flicker has been known for decades, but it had never been used in focusing. Rietman and his colleagues Keith Higginson and Mike Costolo at the company Triton Systems in Chelmsford, Massachusetts, have been commissioned by Buckley to how work out to exploit this effect to bring light to a focus and so create a useful lens. The frame around the silicone rubber disc is the key. It houses a set of piezoelectric actuators that generate high-frequency ultrasonic waves. Waves generated by each actuator reflect back and forth across the frame, setting up an interference pattern. The patterns from each actuator cross in the middle of the lens, and by tweaking the frequency of the actuators it is possible to produce a static interference pattern that makes the centre of the silicone disc less dense than the edges, thereby lowering its refractive index. The result is that the refractive index of the silicone increases further from the centre, so light rays that strike it spread out. As the eye traces the rays back, the object appears smaller and further away. There is, however, a long way to go before the rubber lens can be put to practical use. So far, only an area a few millimetres across at the very centre of the lens shows any change in refractive index. Increasing the wavelength of the ultrasound would extend the area, and Rietman's team is currently trying to build actuators that are powerful enough at these wavelengths. They are also working on liquid lenses. He and Higginson show off a 7-centimetre glycerine lens between two glass plates. The refractive index change is smaller than in the rubber lens, so they make it visible by turning down the lights and aiming a green laser beam through the centre. The beam spreads to a blur on a screen 1.5 metres away until they switch on the power and the blur becomes a bright spot. To make these into useful lenses, the team will eventually have to overcome one big hurdle - chromatic aberration, which also blights conventional lenses. Simple materials like glass bend light of different colours by different amounts: blue light more than red light, for example. This is what makes a prism separate white light into its component colours. But in a simple lens it means that different colours are brought to a focus at slightly different points, causing coloured fringes around objects in cheap telescopes and fuzzy images in cheap cameras. Lens designers can get around this problem because different types of glass disperse colours to a different extent. For example, flint glass has about twice the dispersive power of crown glass. So by combining a convex flint lens with a concave crown lens, the dispersive effects can be made to more or less cancel out. But this comes at the price of vastly increasing the complexity of devices such as telescopes and camera lenses. The human eye has a very different solution to the problem of chromatic aberration. Instead of using numerous lenses made of different materials, the eye's lens is made up of between 2000 and 3000 layers of cells stacked on top of each other. Some layers are thicker than others and have different refractive and dispersive properties, and they are arranged in just the right way to cut out chromatic aberration. Buckley believes that this might point the way to other methods of minimising chromatic aberration, and is funding research into materials inspired by the best features of natural lenses. "We can't use the materials nature has because they're not very robust," he says. But there are artificial nanostructures that may be able to compensate for chromatic aberration in a different way. One idea is to fill the pores in a porous material with certain optical properties with a second material that has different optical properties. Sterling McBride of the Sarnoff Corporation in Princeton, New Jersey, is working on moving transparent fluids inside regularly structured materials known as photonic crystals. As the fluid moves into the pores, it changes the overall refractive index. McBride has changed the focal length of an experimental lens by a factor of 2 in this way, meaning that the distance to the lens' image doubled, without the lens or object having to move. The system acts only on infrared light, but it is promising for the infrared wavelengths in military night-vision systems, McBride says. Another related approach is the work Buckley has commissioned from Shin-Tson Wu at the University of Florida in Orlando. Wu is working with liquid crystals, which are made up of cigar-shaped molecules that tend to align themselves with an electric field. Light travelling in the direction of the long axis of the molecules experiences a different refractive index than light shining across the long axis. Wu can vary the strength of the field to change the refractive index of the material as more molecules become aligned. It has proved difficult to make liquid crystal lenses big enough for imaging devices, but by suspending nano-sized droplets of liquid crystal in a polymer, Wu has been able to create larger variable lenses. He varies the distribution of the liquid crystal droplets in the polymer so that the refractive index changes with distance from the centre of the lens. Applying an electric field changes the refractive index of the liquid crystals, with the largest changes in areas where the crystals fill more space. Another approach commissioned by Buckley avoids the problem of chromatic aberration by concentrating on a narrow range of wavelengths. Instead of liquid crystals, SBA Materials of Goleta, California, is using photochromic materials, like those used to turn spectacles dark when the light is bright. These materials consist of molecules that can exist in two states - a light-absorbing state that makes the lenses look dark, and a light-transmitting state that makes them clear. The molecules are switched between these states by light itself. Switching the molecules to a light-absorbing state also increases their refractive index at wavelengths close to the one that is absorbed. The materials being investigated by SBA are photochromic to visible and infrared light, but when they switch between states, they change the refractive index for the nearby blue or red visible light. This means that they could form the basis of UV or infrared-activated variable-focus lenses for visible light. Like Wu's team, SBA is also working on materials that change state in an electric field rather than when bombarded with light. Demonstration of variable refractive power in single lenses is only a first step. Buckley is already thinking up ways in which the technique could be exploited for more complex systems and has put together some designs showing what optical systems of the future might do. One application he has in mind is as a replacement for complex, heavy and delicate zoom lenses. While a single variable refractive index lens could not do the job of zooming by itself, because the image could not be both magnified and remain in focus, Buckley has shown that two of them separated by a fixed distance could. That could make zoom lenses much simpler and more compact than they are now. Buckley also has some more exotic ideas, one of which he presented at a conference of the SPIE, the International Society for Optical Engineering, in Rochester, New York, last year. In the human eye, the central region of the retina has the highest density of light-sensing cells and so provides us with our detailed, high-resolution vision. While we can vaguely perceive objects in our peripheral vision, we have to move our eyes onto them if we want to study them. Buckley wants to mimic this ability of the human eye but without the lenses having to move. The idea is to control the refractive index across the lens so that, while one part of it focuses closely on one spot, the rest of the lens watches the surrounding area in less detail. If anything interesting happens elsewhere, the focus could shift. A zoom lens made from variable refractive index lenses would be able to magnify part of its field of view without having to move, allowing a camera to zoom in for a close-up while keeping its peripheral vision alert for other action. In optical systems linked to image processing computers, the technique could dramatically reduce the processing power needed to analyse images by allowing a processor to gather fine detail on the most interesting parts of a scene while ignoring the rest. And because the lens does not have to move, optical systems could change their focus, gather data and move to decisions far more quickly. A car fitted with an infrared night vision system could zoom in and out quickly, spotting different objects on the road while moving at speed. Just how fast all this could happen is anyone's guess. It'll be some years before these concepts can be turned into the high-quality lenses needed by commercial imaging systems. But once that happens, the design of optical systems will undergo a revolution and lenses will never be quite the same again. Jeff Hecht 5:49:20 PM    comment []

WE ARE NOT THE ONLY ONES WORRIED ABOUT DISPARITY OF WEALTH CAUSED BY OUTSOURCING: The pattern of responses did not correlate well with country of origin. One interesting example concerned fears about the two-tiered economy created by job exportation. Before concluding, "These trends cannot be stopped by any government," A. J. Balasubramanian pointed out that due to job importation, "In India, we are creating two different societies with a large disparity in income as well as access to knowledge and information." 5:38:09 PM    comment []

AS IF THERE WASN'T ENOUGH TO WORRY ABOUT...AVIAN INFLUENZA.  I AM GOING TO CHINA NEXT MONTH...PITCHING FOR WORK.  I HOPE I DON'T GET SICK. http://msnbc.msn.com/id/4058992/ A horror script for health officials Bird flu poses global epidemic threatBy David BrownWASHINGTON, Jan. 25 - The metaphor that public health officials invoke when talking about a global flu epidemic is the same one that lies at the heart of the scariest horror movies. advertisement It is the idea of a small and deadly thing that is poking and prodding for a weak spot in whatever is protecting its intended victims. It is patient, because it knows it will eventually succeed. When it does, a horrible metamorphosis makes it huge and unstoppable. This plot was a deadly hit in 1968, 1957 and, most notoriously, 1918, when pandemic influenza killed about 50 million people worldwide. Today, virologists fear a remake is underway in East Asia. Over the past month, a strain of bird flu that has killed thousands of chickens in nearly half a dozen countries has broken through the "species barrier" to claim a few human victims. This time, though, the public health community hopes to write a different end to the script. "There is a chance that something can go wrong," Klaus Stohr, head of the World Health Organization's flu program, said Friday in Geneva. "But it looks as if we act decisively and timely now, there is a window of opportunity here to control the disease before it takes global proportions." That action consists of exterminating chickens carrying the virus, protecting people in contact with the birds from infection and understanding the pathogen at the molecular level -- all as quickly as possible. Cross-border traffic of live birds and poultry products has stopped in much of the region, and there is talk of vaccinating millions of chickens. So far, there is no evidence that this bird flu can be passed from person to person -- a trait it would need to acquire to make it a global threat. "Everyone has their ear to the ground. That is the big question, isn't it?" said Robert G. Webster, one of the country's leading influenza experts, who jetted to Hong Kong two weeks ago to study the new strain. Stakes could be higher than SARS If evidence of person-to-person contagion appeared, the already urgent response would escalate dramatically. Borders would close, the ill would probably be quarantined, and a crash program to make a new version of the annual flu shot would begin. The response would be much like the one mounted against severe acute respiratory syndrome (SARS) a year ago. The stakes would be much higher, however, because the flu virus, once fully adapted humans, can spread with a speed and ease that SARS never showed. A lot has to happen, though, for bird flu to gain that capacity. The trouble is that in influenza's world, a lot can happen very quickly. Health authorities in Vietnam are investigating 30 suspected cases of bird flu in people. Fourteen have died, most of them children under age 12. In six cases, laboratory testing identified a strain of avian influenza designated H5N1. Late last week, two children in Thailand -- both still alive -- were diagnosed with H5N1 flu. The H and N denote two proteins, hemagglutinin and neuraminidase, that sit on the outer shell of the virus. Together, they provide a virus's chemical appearance to the immune system. The particular combination of H and N is the key to a strain's identity and the first hint of whether it might be a danger to people. There are 15 forms of hemagglutinin and nine of neuraminidase in the most populous class of flu viruses -- influenza A. (The less common and less dangerous influenza B has only one type of H and N). When a virus with a new H-N combination appears, immunity built up to older ones is no help. What follows can be a worldwide epidemic -- assuming the virus also grows well in people and is spread easily in coughs and sneezes. How pandemics happen The great pandemic of 1918 was H1N1. It was unquestionably new, although what strain it replaced is not known. In 1957, an H2N2 virus appeared in southern China, triggering a pandemic of "Asian flu." In 1968, an H3N2 virus appeared, causing the global "Hong Kong flu." In 1977, H1N1 reemerged -- by then, nearly everyone under age 20 had never seen it -- and caused a mini-pandemic. There are many H-N combinations, however, seen only in other species, particularly birds, which are the real home range for flu virus. The feared H5N1 is one of them. It can tear through chicken flocks with a mortality approaching 90 percent. But virologists did not think it could infect people -- at least, not until 1997. That year, 18 people in Hong Kong became infected with H5N1 -- the first time direct bird-to-people transmission had been seen. Six died, most of them healthy young adults -- a disturbingly high percentage. Previously, scientists believed that to infect and kill a person, a bird flu virus would first have to acquire at least a few genes from the flu viruses that regularly circulate in human populations. That is possible because unlike viruses whose genes reside on a single unbroken strand of RNA or DNA, flu carries its genetic information on eight separate strands. Under the right conditions, it can trade one of more of them with another flu virus, like a card player in a game of hearts. Virologists once believed these "reassortments" occurred only in pigs, because that species were capable of being infected by both human and avian flu. With the 1997 Hong Kong cases, however, it was clear reassortment might also occur in a person simultaneously infected by both. The chance of that occurring depends on how much avian flu is around. What scares scientists this winter is that it is all over the place -- in flocks in Japan, Vietnam, South Korea and now Thailand. "It is an unprecedented situation with H5N1 virus in so many countries around Asia," Webster said. "The extent of the spread of this virus has not been seen before." Chickens slaughtered across Asia How H5N1 became so widespread is not known. The urgent chore is to get rid of the animals harboring it. In recent weeks, tens of thousands of chickens have been killed in flocks in Japan, Vietnam and Thailand. The number could go much higher. It is important to protect the workers culling the flocks from getting human flu, lest they themselves become the "mixing vessels" in which a reassortment occurs. WHO is urging they be vaccinated, and if possible be given preventive medicines. Even without reassortment, it is possible that avian influenza could become a pandemic strain, but that is far less likely. "Given enough time and enough opportunity, viruses could go through a process of human adaptation and become more transmissible than these ones are at the moment," said Nancy J. Cox, the head of the influenza program at the Centers for Disease Control and Prevention. "We know, though, that in 1968 and in 1957 the strains were reassortments between human and avian viruses." Curiously, Hong Kong, where the first human cases of bird flu occurred, is reporting no H5N1 now. That region changed its poultry-marketing practices after the 1997 outbreak. Waterfowl, which can carry H5N1, were separated from chickens. Quail, also viral hosts, were banned. Markets were also required to be cleaned twice a month. People were thought to have been infected by breathing an infectious dust stirred up when chickens, whose feathers were contaminated with virus-containing feces, were taken flapping from their cages. Still, H5N1 continued to turn up occasionally until last year, when a poultry vaccine began to be used widely, Webster said. Today in Hong Kong's markets, he said, "every chicken has had its shots." 5:34:55 PM    comment []