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| SCIENCE & TECHNOLOGY |
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Can
animals replace doctors? Building
tips
UNDERSTANDING THE
UNIVERSE
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Can animals replace doctors? Rats of one species in Africa are being trained to detect tuberculosis (TB) by sniffing the saliva of suspected TB sufferers. The rats have already been successfully used to detect landmines by their odour. Preliminary tests suggest the rats could test as many as 150 saliva samples for TB in just 30 minutes. By contrast, human technicians using a microscope can test only 20 samples a day. It is vital to detect TB as early as possible. TB is curable, with early detection, good healthcare facilities and access to drugs. The rat study, which will begin in July, 2004, will test the olfactory abilities of about 30 rats. The researchers will compare the rats’ adeptness with the 95 per cent accuracy of smear microscopy. Preliminary results look positive. The researchers used bananas and peanuts to reward rats when they stopped beside a target smell. In this way, they sensitised five rats to the smell of TB bacteria in saliva and another five to the smell of TB bacteria grown in test tubes. The rats were then tested using 10,000 saliva samples and they identified about 77 per cent of infected saliva samples. Researchers hope that using three or four trained rats on each sample will increase the accuracy. The rats scored better — nearly 92 per cent — with cultured bacteria. The number of samples where rats stopped at uninfected samples, was less than 2 per cent for both cultures and saliva. The idea came through a clue in the Dutch language. The Dutch word for TB is “tering”, which translates roughly as “the process of developing the smell for tar”. The researchers also had read reports of traditional Chinese healers diagnosing the disease by smelling the patient’s saliva as it evaporated over a flame. Researchers are now studying ways dogs — our four-legged friends — could help diagnose diseases. Dr Lawrence Myers and his team are teaching them to sniff out suspicious odours. One day, these dogs could be sniffing out odours from skin cancer. A dog’s sense of smell is actually up to 100,000-times more sensitive than a human’s. Doctor Myers envisions a future where dogs will work side by side with doctors. People simply can go to a skin specialist’s office, and the dog can check them over, instead of waiting for them to notice an abnormally shaped or coloured mole. Dr Barbara Sommerville, of the Cambridge University in the UK is planning to use dogs to detect prostate cancer. She hopes to train dogs to react to cancer cells in urine samples. This would revolutionise the screening process for detecting prostate cancer early. Dr Sommerville has no doubt that if there were a consistent change in odour the dogs will be able to detect it. As of today, detecting prostate cancer is an inexact science. The currently used methods provide a lot of false positives and some false negatives. However, dog trainers believe that they could train dogs to sniff out prostate cancer in a period of six months. Dogs have also been used to assist people suffering from epilepsy. The dog tells the owner that they are about to have an attack. It makes sense to investigate if the dog can help the diagnosis in any disease where chemical clues are coming from the body. The aim is to put together the dog with current conventional diagnosis and simply get much better results faster and cheaper. Dog trainers train dogs to help with a range of conditions. There are dogs that alert the owner to blood sugar, high blood pressure, migraine headaches, heart attacks and the like. However, dogs aren’t the only ones with a nose for medicine. A diabetic woman says that her cat known when her blood sugar is low. The cat keeps nudging the woman until she checks it and sure enough she finds it to be low. The woman lives alone. If her blood sugar falls when she’s asleep or if it drops too low, too fast, and she’s already disoriented, the cat’s watchful eyes would save her life. The cat would deliberately come over and touched her face or actually nipped at her leg until the woman got out of bed and took appropriate medicine. A study in the British Medical Journal adds weight to this phenomenon, and a survey shows that nearly 70 per cent of dogs who sensed their owner’s low blood sugar reacted to it. |
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Building tips Buy
GI pipes for water supply pipelines yourself and don't leave their choice to the plumber. Go for Medium class pipes. These are also called B Class pipes. Remember that the categorisation is in reverse order. Class A pipes are lightest and cheapest and Class C pipes are heaviest and costliest. Buying Class C pipes will not be economical. So select Class B pipes. A visible mark for a B class pipe is that it carries a blue band of 3 inch length at each end of its 6 metres or 20 feet length. A Class pipes carry yellow bands and C class pipes carry Red bands. Scratch the blue band a bit to check that blue colour has not been painted over the yellow to deceive you. Look for ISI Mark on the pipes. *
* * These days, mostly, PVC conduits are used for carrying electric wiring in the house. When the roof slab of the house is laid, a network of these conduits is also embedded in the RCC slab. These conduits are not able to develop a bond with the concrete. As a result, hair cracks appear in the slab along the conduit lines. To avoid this, adopt a simple remedy. Take some binding wire that is used to tie steel reinforcement and wrap it firmly around the conduits in helical fashion. The wire will develop bond with concrete and cracks will be avoided. *
* * There is a great variation in the shape and style of joinery fittings as more and more ornamental fittings having different finishes are in use today. Though it is an individual's choice to select the colour, finish and material, take care that basic requirements of strength and functional use are not overlooked. Fittings must be smoothly operative and shouldn't have sharp edges to bruise your arm or tear the clothing. Check the tower bolts and sliding bolts for smooth running, handles for sufficient width and depth for the grip. Check the cut portion of tower bolts against sharp edges as these harm the fingers during operation. Check the tower bolt crowns to match the barrel sizes. Select big and strong hasp and staples for Cup boards. *
* * Screws used to fix door and window fittings need selection. Good screws will not lose grip or shall not widen the screw holes with the passage of time. Look for steel screws conforming to IS 1812. Also look for Slotted-Counter-Sunk Head wood screws. Look for their shaven heads. Shaven heads are bright and finished plain at the lathe while unshaven heads look unfinished. Choose right length, not too long also, as it may pass through full thickness of wooden member, tearing it apart. A 6X25 screw means a screw of 25mm length drawn from no. 6 wire gauge. A packet has 200 screws when length is less than 25mm and 100 screws when length is more than 25mm. |
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UNDERSTANDING THE UNIVERSE More radio stations are available during night time. Why? How do the space vehicles penetrate the moon’s atmosphere without the help of a rocket? The moon does not have an atmosphere. There is nothing to penetrate. However, landing on the moon, or any other planetary body, does require that we should be able to manoeuvre the rocket when it arrives in its neighbourhood. If we do not do that one of the two things would happen. Either it would go past that body or it would crash into it. Slowing also needs energy transfer, as does acceleration. That would require some rocket power. Why does a magnetic needle point only in the north-south direction? If you have played with magnets you must have discovered that they have two poles. If you have two magnets then the side A of one may attract side B but repel side A. A magnetic needle is also a magnet of this type. It seems to orient itself as if there is another invisible magnet in its neighbourhood. That invisible magnet is the Earth itself. The Earth has a magnetic field and it seems to be of a kind as would be produced by a large bar magnet inside, oriented in the north south geographic direction. Earth’s magnetic field is a reality. How it is produced is beginning to be understood. Approximate alignment of this field with north south direction is the reason that the magnetic needle on the compass points in the north south direction. The earth rotates around its axis. Suppose an airplane after taking off stands still in the sky. Can it land at the same place after 24 hrs? Let us assume that you do this experiment at a point over the equator. This means that when you start you would be moving eastward, like the airport below you, at about 1000 miles per hour! You do not feel this motion because the air mass is rotating with the earth. If it were not you would have quite a hurricane blowing over the earth surface. So in order to stay over the same place over the earth surface you have to be flying through the air at that speed. You do not quite succeed and therefore end up in Brazil after 12 hours - the rotating earth leaves you behind. But you can keep going and would be back at your starting point after another twelve hours. You could say that you have been unsuccessfully trying to stand still, but only with respect to the air mass around you. But your plane would be tired and you would have consumed a large amount of fuel. At some higher latitude you could fly westward at a specific subsonic air speed and stay over the same town no matter how long you fly. |
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Rock-solid robot car
It looks like a cross between a Hummer and a tank. But the squat, pug-nosed car with brown body panels in place of its windshield and windows is radically different from any vehicle on today’s roads or battlefields. Designed, built and outfitted by the University of Florida and a Utah company called Autonomous Solutions, it is a robot car built for one purpose: to compete against other “autonomous” vehicles in a U.S. defense agency-sponsored race this spring from Los Angeles to Las Vegas. It’s billed as the biggest robotics competition in history. “No robot has ever come close to achieving anything like this before,” said David Armstrong, the project manager at UF’s Center for Intelligent Machines and Robotics and the leader of the UF team. “It’s going to be huge, and we’re going to be there.”
To most people, the word computer conjures up an image of a PC sitting on a desktop. According to a new study, however, complex computations may also be underway in another bit of office equipment: the potted plant that brightens up the windowsill. Plants may perform what scientists call distributed emergent computation. Unlike traditional computation, in which a central processing unit carries out programmes, distributed emergent computation lacks a central controller. Instead, large numbers of simple units interact with each other to achieve complex, large-scale computations.
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Long distance radio transmission is at wavelengths that can be reflected back to the earth by the ionosphere. This reflection depends on the character of the ionosphere at that time. Since ionisation of the upper layers of the atmosphere is caused by solar radiation, including its ultraviolet component, it is not surprising that the steadiness of the reflection and refraction of radio waves would be better at night. This leads to better reception. Another reason is that at nighttime the number of local radiating sources is less; because of this the noise is also reduced.