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| SCIENCE & TECHNOLOGY |
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Bionic limbs: A big hope
Fuel from wood scrap
Mummified dinosaur reveals its secrets
Basking in moonlight
PROF YASH PAL
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Bionic limbs: A big hope
Such injuries require enormous lifestyle adjustments and rehabilitation. A person with such a disability always feel distracted from his life when he see the physically vibrating world all around him and this also put a great pressure on his care-givers. Every such person has a desire to have his natural limbs back, but that is not going to happen. A conventional prosthetic limb which is possible at present is limited in a number of ways in the types of movements. Moreover, it can do only one of those movements at any particular moment. But with the development of biosciences and engineering (called neuro-engineering, the new technology which connects people to machines), days are not far away when such people will be able to have bionic (bionic — a mechanical device directed by brain) limbs which will not be real but nearly real. Jesse Sullivan from Tennessee (US) is the first amputee with a thought-controlled artificial arm. Experts say that a natural arm is capable of 22 discrete movements and Sullivan's bionic limb is capable of four right now which allows him to rotate his upper arm, bend his elbow, rotate his wrist, and open and close his hand — in some instances simultaneously, though researchers are working to make them better. The motions are coordinated and smooth because a bionic or myoelectric device is controlled by the brain. He thinks “Close hand,” and electrical signals sent through surgically re-routed nerves make it happen. Until now, it has been nearly impossible to recreate the subtle and complex motion of a human arm. Improving the function of artificial arms remains a considerable challenge, especially for high-level amputations where the disability is the greatest. Externally powered hooks, hands, wrists and elbows are available, but existing control methods are inadequate. That prompted researchers to make improvements to refine artificial limbs that connect body and mind. Bionic arm is not as smooth as a normal arm but it works much smoother than a normal prosthesis arm. There is no perceivable delay in the motions of bionic arm which is flesh-coloured and plastic-like arm. The technology that Jesse uses today was developed by Todd Kuiken, MD, PhD, Rehabilitation Institute of Chicago (RIC)'s Director of Amputee Programs and Associate Dean for the Northwestern Feinberg School of Medicine and his team at RIC's Neural Engineering Center for Artificial Limbs (NECAL). Researchers have learned that although the limb is lost with an amputation, the control signals to that limb remain accessible in the residual peripheral nerves. Grafting the residual nerves of an upper-limb amputee to spare muscles produces additional control signals, allowing for simultaneous operation of multiple functions in an externally powered prosthesis with a more natural feel than is possible with conventional prostheses. The writer is from the Department of Physics, S.L.I.E.T., Longowal |
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Mummified dinosaur reveals its secrets
British researchers involved in the project say the near-perfect preservation of the plant-eating dinosaur’s skin has enabled them to build up an exceptional picture of the animal, including the ability to estimate its top speed of 28mph. This means that the duck-billed dinosaur, belonging to a group called the hadrosaurs, could outrun the top predator, Tyrannosaurus rex, which shared the same terrestrial habitat as the hadrosaurs 67 million years ago. The dinosaur was first discovered in 1999 by a budding scientist called Tyler Lyson, who was then just 16, on his family’s land in North Dakota, but it is only in the past year or so that scientists have realised its significance. Phillip Manning of Manchester University, who has worked alongside Mr Tyler, who is now at Yale University, to investigate the fossil, said that it is unusual to have a dinosaur specimen with such a large segment of intact skin, especially since the skin has not been flattened in fossilisation. “It is quite fair to say that our dinosaur mummy makes other dinosaurs look like road kill. Simply because the evidence we’re getting from our creature is so complete compared to the disjointed sort of skeletons that we usually have to draw conclusions from,” Dr Manning said. “It lived in a flood plain so it really is unique for the skin to survive. Plant-eating dinosaurs have a reputation for being pretty boring but this find changes all that.” “Here, for instance, we can use the skin to estimate the size of the muscles it must have enveloped, and this can be done on this specimen more so than any other dinosaur in history.” — The Independent |
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THIS UNIVERSE
The earth is said to weigh 594 followed by many zeroes of metric tons. I want to know how such huge bodies are weighed so accurately. You know, of course, that it would be ridiculous to think of a large balance to do this for us. It is even more ridiculous to find the "weight" of the earth, because the earth, like everything in else in space, is weightless. On the other hand we are well placed to determine its mass or inertia, because there are other bodies against which we can study its interaction. An obvious choice is the moon. The moon goes around the earth. If we measure the distance to the moon and the period of its revolution around the earth, we can get a pretty good measure of the mass of the earth. All we need to do is to use Newton's equations. The measurement can be improved if we use geodetic earth satellites in accurately defined earth orbits. Masses of all the heavenly bodies, including that of the sun, are determined in this manner. The limit on the accuracy would be the precision of our value for the Cosmic Gravitational Constant. Kindly tell me if there is any proof that electrons inside and outside of the atom have identical mass, charge and velocity? If the Bohr radius is 0.529 times 10 to the power of minus 8 cm and the speed of the electron is less than the speed of light, is it possible to measure the very small "atomic time"? I do not see how the mass and charge of the electron can vary. If it did where would the excess or the deficit go? If the picture of the orbiting electron is taken seriously then its speed could be considered as varying in a manner similar to that in a Keplerian orbit, though I do not know where this speculation is taking us. I suspect your concern about the " atomic time" accuracy is connected with the width of the spectral lines. This might be mitigated to some extent by the fact that in practice we do not use the single electron in just one orbit. When we heat glass it cracks. But when it is heated to high temperature it converts into a liquid state. Why? We know that glass is not a good conductor of electricity. We also know that glass expands when heated. If some part of a glass vessel is heated it tries to expand. The neighbouring parts, being cooler resist that expansion. Since glass is brittle, unlike metal, it shatters. If, on the other hand, the heating is slow and uniform we can heat glass to a high temperature without it shattering. Turning into liquid would happen irrespective of whether the piece of glass shattered on the way. Usually such heating is done gradually, sometimes in a furnace and sometimes over a flame when the sample is continuously rotated.
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