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| Sunday, 10 April 2005 |
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Science Watch out for that twister Tornadoes! is it the latest natural disaster that might plague the country? Many people are anxious about tornadoes since a news-cast on the electronic media about a tornado-like formation around Sri Lankan coastal towns in the western province. Increased incidence of tornado-like wind formations have been observed in and around Sri Lanka in the past 5 years.
However, whether Sri Lanka falls in the path of tornadoes or not, it is best that we be informed about tornadoes. Contrary to the belief that tornadoes form from isolated storm cells in the evening in springtime, a significant number of tornadoes form under unexpected circumstances, say scientists from Purdue University, USA after a survey of 3,800 tornadoes that formed over the United States from 1998-2000. A Purdue University study of tornado formation indicates that twisters or tornadoes can develop in unexpected ways and at unexpected times and places, a discovery that presents a new twist to weather watchers across the country. Although tornadoes are often conceived of as arising from springtime storms that develop in early evenings out of isolated weather cells, a new study spearheaded by Purdue's Robert 'Jeff' Trapp indicates those conceptions often fail to hold. After examining data on more than 3,800 U.S. tornadoes, Trapp's team has found that many twisters develop within the line-shaped storm fronts that often sweep across the country. The twist is that these are tornadoes that are more likely to form late at night and in colder months. "The upshot of our analysis is that tornadoes form under a broader set of circumstances than meteorologists once thought," said Trapp, an associate professor of earth and atmospheric sciences in Purdue's College of Science. As a first step toward improving the ability to predict tornado strikes, which often come with only a few minutes' warning, the group initially set out to find what types of storms generally produce the destructive funnels. "In the heart of Tornado Alley, tornadoes most often develop from relatively small 'cell' storms that look like blotches on a Doppler radar weather map. Over time, these cells frequently merge into line-shaped storms that can stretch hundreds of miles. The conventional wisdom has been that line storms don't often spawn tornadoes, but we found that a significant number did," Trapp said. Out of 3,828 tornadoes analysed 79 per cent had come from cells and 18 per cent from line storms nationwide. Cell storms often form in springtime in the late afternoon, which is why most storm warnings are issued in the evening, Trapp said. But line storms often form later at night and also in the cool season, between October and March. "These are the hours and months when people probably least expect severe weather," Trapp said. "In fact, they may not even see a tornado coming because of the lateness of the hour." "We're not trying to be alarmist with these findings," he said. "But we hope that people will stay alert to tornado risk even outside the traditional severe storm season." Trapp said that the current study represents a step toward better weather prediction, but there's still much work to be done on the problem. "This paper is meant to be the first in a series of studies of tornado development," Trapp said. "Now that we have a better picture of when and where they form, we can begin to develop tools that can serve a practical purpose. For now, we are merely trying to raise awareness among weather watchers about tornado-forming situations that, until now, have been, figuratively speaking, beneath our radar." This research was funded in part by the National Science Foundation. Trapp is affiliated with Purdue's climate and extreme weather group as well as with the Purdue Climate Change Research Centre. The centre promotes and organizes research and education on global climate change and studies its impact on agriculture, natural ecosystems and society. (Courtesy - Newswise) Powerful bite Contrary to popular belief about the force of the bite of different carnivores, scientists from the University of Sydney finds that the marsupial lion, one the greatest carnivores to roam Australia, had the most powerful bite of any mammal species - living or extinct. None had the ability to bite down on its prey with quite the same force, say Dr Stephen Wore and colleagues. Pound for pound, Thylacoleo carnifex was biting way above its weight. Wore's team studied the skulls of 39 mammalian carnivores, eight of them now known only from the fossil record. The lion, so described because of its cat-like appearance, became extinct more than 40,000 years ago. Fossil evidence shows it must have been a remarkable predator. Its stocky teeth, although not quite on the same scale as those of sabre-toothed cats, would have inflicted terrible flesh wounds. The lion also had a huge "thumb claw" to grapple with and disembowel its victims. "Thylacoleo carnifex was one of the meanest, most frightening animals you could have the misfortune to meet," Dr Wore, from the University of Sydney, told the BBC News website. Stress help fight the flu Suffering from stress? Do not worry. That is if you do not want to succumb to the influenza virus. A new study in mice suggests that, in certain cases, stress may enhance the body's ability to fight the flu. Short bouts of intense social stress improved the ability in the mice to recover from the flu. The stress apparently did so by substantially boosting the production of specialised immune cells that fought the virus. "Stressed mice had a stronger immune response and were able to fight off the infection faster," said Jacqueline Wiesehan, a study co-author and a graduate fellow in oral biology at Ohio State University. Wiesehan, David Padgett and John Sheridan, the study's lead author and a professor of oral biology at Ohio State, presented their findings on April 3 at the Experimental Biology 2005 conference in San Diego. The three also worked on this study with Michael Bailey, a postdoctoral fellow in oral biology at Ohio State. The special immune cells that fights influenza virus are called T cells and are part of the immune system's memory response. T cells "remember" specific infectious agents and can launch future attacks against these intruders. At the beginning of the study, some of the mice were caged in groups of three. One aggressive mouse, meant to disrupt the social environment in the cage, was put in each of these cages for two hours at a time for six consecutive days. At the end of the last stress session, the researchers infected both the subordinate mice that had endured stress and those mice that weren't caged with an aggressive mouse with a strain of influenza virus that can also infect humans. The mice were infected through their noses. This was the first time that the animals' immune systems had been exposed to the virus, and the researchers wanted to see what effect the stress would have on the immune system's memory response. Three months later, the researchers injected either a small amount of saline solution or influenza virus into the footpad of one hind paw of each mouse. This kind of viral challenge caused what scientists call a 'delayed-type hypersensitivity' response; the skin test routinely used to test a person for tuberculosis also causes this kind of response. "It takes about a month for the body to develop a strong pool of memory T cells that are ready to fight another virus," Wiesehan said. "We waited a little longer to make sure this memory response was in place." The influenza challenge caused the infected paws to redden and swell. The researchers measured the thickness of paws daily until the swelling went down - this measurement gave the researchers an idea of the number of cells responding to the viral antigen. The affected paws of the stressed mice were noticeably more swollen than those of the non-stressed mice, suggesting that the immune system's of the stressed mice had had produced more immune cells that could respond to this strain of flu virus. The researchers hope to learn more about the mechanisms behind the memory response, and to use this information to develop more effective flu vaccines in the future. New flu vaccines are created every year, and, according to the World Health Organisation, are about 70 to 90 per cent effective in preventing influenza. - Newswise Another planet? Is there life beyond earth? A topic of much controversy and deliberation. However, scientists are detecting new planets orbiting stars far away. Astronomers have found about 130 exoplanets over the past decade, but most of these have been detected via the gravitational 'wobbles' they induce in their parent stars. The limitations of current technology make it very difficult to see a planet directly. Recently, an European team claimed to have obtained the first direct image of a planet beyond our own Solar System. The "extrasolar planet" is said to orbit a star called GQ Lup - thought to be like a young version of our Sun. GQ Lup and its companion are located in a star-forming region about 400 light-years away. The astronomers have used image data from the European Southern Observatory's (ESO) Very Large Telescope (VLT) in Chile, the Hubble Space Telescope and the Japanese Subaru Telescope in Hawaii. The 'planet' has been observed by the team since 1999. - BBC It's no joke, animals laugh You do not have to laugh at the research content some US researchers have revealed recently. They have discovered that animals do laugh. Many animals may have their own forms of laughter, says US researcher Professor Jaak Panksepp writing to the Magazine of Science. He says that animals other than humans exhibit play sounds that resemble human laughs. These include the panting sounds made by chimps and dogs when they play and chirping sounds observed in rats. This suggests that the capacity for laughter may be a very ancient emotional response that predates the evolution of humankind, says Panksepp. Research suggests the capacity for human laughter preceded the capacity for speech. Professor Panksepp, explains that neural circuits for laughter exist in "ancient" parts of our brain, whose general structure is shared amongst many animals. Young chimps 'play pant' as they mischievously chase and tickle each other. And when rats play, they make chirps which some scientists associate with positive emotional feelings. When rats are tickled in a playful way, they become socially bonded to humans and are rapidly conditioned to seek tickles, the US neuro-scientist explains. However, other researchers prefer to view laughter and joy as uniquely human traits. 'Body talk' controls mobiles If you are an owner of a mobile digital music player, the way you change its music tracks a nod of the head, the same way you gesture to a walky - talky friend is drawing closer say researchers. The University of Glasgow researchers have been developing 'audio clouds' to control gadgets using movement and sound. Presenting their work at a US computer interface conference, they say audio clouds could make using mobile devices on the move safer and easier. There has been a large body of work looking at different ways to control devices through vision-based gesture recognition, Professor Stephen Brewster told the BBC News website, but not so much has concentrated on movement. "Lots of times, you need to use your eyes to operate a gadget - even with an iPod, you need to take it out of pocket to look at the screen to control it. If you could do something with your hands, or other gestures you would not have to take it out of your pocket," explained Professor Brewster. The researchers have developed ways to control gadgets, such as personal digital assistants (PDAs) and music players, using 3D sound for output and gestures for input. - BBC |
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