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Wizardry of atomic engineering Tomato gene sequencing Freshwater rights
Prof Yash
Pal The
Universe |
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Wizardry of atomic engineering
For 30 years now scientists have been achieving a steady increase in the number of transistors that can be carried by one silicon chip. As a result, the power of computers becomes 1000 times greater every 10 years. Whether that enormous rate of progress can be maintained is debatable. If the current process of microchip manufacture is unchanged some experts predict that the limit of improvement will be reached around 20 I 5 when computer technology may begin to stagnate At present, the microchip designer draws a diagram of complicated electronic circuitry which is photographed and then miniaturised. A laser beam fired through the film etches the microscopic diagram on the chip. In that way an incredibly tiny, complex wiring diagram involving millions of transistors can be placed on one silicon chip. This process is called photolithography. The maximum number of components that can be fitted on a chip will be dictated by the wire’s diameter. The thinnest wire imaginable would be a row of single atoms — a remarkable concept that might not even function. It does, however, provide us with a definite limit to the size of silicon chip components. That limit is unattainable using photolithography because a laser beam cannot pass through spaces in a microscopic film diagram smaller than its own wavelength. Shorter wavelengths, high-energy electron and ultraviolet beams have been tried but all these techniques have their own limitations.
Microscopic robots Some farsighted scientists are considering a fundamentally different way of manufacturing microchips. Instead of reducing large objects to microscopic size — the top-down method — they advocate a bottom-up mode of construction wire by wire. Transistor by transistor. These nanotechnologists visualise individual molecules, even perhaps individual atoms, being placed in specific locations. With current techniques the time required to lay down the billions of atoms required renders that process untenable. To achieve the aim scientists have proposed the development of nanorobots. Several hundred thousand and possibly several million of these microscopic robots would descend on a silicon chip like a swarm of locusts on a field of corn and deposit their molecule-sized components one by one. ‘By such a method highly complex devices could be assembled on a realistic timescale. This technology may have applications far beyond computer chips. Individual atoms might be built into fabulous new materials — fabric light as a feather yet hard as a diamond; unbreakable rope; computers with an intellectual capacity far in excess of the human brain. The possibilities are endless. Having developed through Stone, Bronze and Iron ages, mankind may be about to enter the Nano age. And if we want to convince ourselves of the potential of nanotechnology we need look no further than our own bodies. Nature relies on this very concept in assembling the individual proteins built into the human body according to the design encoded in our DNA. Nano fabrication is possible and the results are staggering. You are the living, breathing proof.
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Tomato gene sequencing India, with nine other countries, has started gene sequencing of tomato as part of an international project aimed at increasing the vegetable’s yield, nutrition and disease resistance properties. The process, which is likely to be completed in the next five years, would serve as a global source of information on tomato and help improve its nutritional and disease resistant varities, Prof Akhilesh Tyagi of the Department of Plant Molecular Biology, University of Delhi, has said. “Full genetic information of tomato will greatly enhance conventional breeding strategies and enable the generation of new crop varities with improved disease resistance,” he said adding yield increase was the foremost concern. After completion, the project would help scientists pinpoint desirable characterstics in the genetic makeup of the tomato that could be introduced into other plant varieties through conventional breeding techniques, he said. Tomato, a significant commercial crop worldwide, is a model plant species for studying quality traits in all fleshy fruit bearing plants, he said adding: “Beta carotene, that is found in tomato, is known for its anti-cancerous quality.” Its qualities such as preventing heart disease and boost immunity could also be introduced in other plants, he said. Information about the gentic makeup of tomato and utilisation of the available knowledge base to improve the quality of the vegetable are the two components the scientists, at present, are looking at, he said. — PTI
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Freshwater rights
Heard of fundamental rights of man? Never heard of fresh water rights? Better do for your own sake. At the greatest GEOEXPO in August, 2004 in Florence in 32nd International Geological Congress I saw ironically these rights on beautiful pamphlets going abegging in huge waste paper baskets. The document originating in Spain gave these 10 water commandments that Freshwater has the right to be:
Glaciers and ice caps, the so-called fixed deposits of fresh water may be on their way out. The mineral water industry already flourishing is likely like pharmaceutical industry to soon co-exist with a spurious counterpart. How long are we going to use drinking water for watering lawns, washing cars and cattle? If we do not get out of this luxury, we’d be fighting street wars over fresh water. To be retaining our rights for safe drinking water even within cities, we need to launch a mass communication programme in effective and thoughtful ways to enforce Freshwater Rights. Those who may consider these to be a joke will find themselves on the receiving end not very far off in the future.
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The Universe Q. While walking our dog, we came across several runners pass by us. We wondered why does the runner use more energy than a walker for covering the same distance? According to the law of conservation of energy, sure both should use the same amount. What is going on? A. I do not know whether I can find a satisfying answer to your beautiful question but let me try. Firstly I doubt if the total energy used by a walker and a runner is the same. Consider the following points: Imagine a person standing next to wall trying to push it out of the way. He is using a lot of force, straining a lot without being able to move the wall. It is clear that he would get tired after a while. The wall does not move but the person does expend a lot of energy. Where does it go? It goes into twisting and pumping his muscles, sometimes causing a sprain, abrasions on his palms. It also generates heat — yes heat —because when stored energy of the body is converted into mechanical energy the body works as an engine and when that happens a significant fraction of the energy is lost in heat. When energy stored in petrol is converted into mechanical energy of a motorcar at least half of it is lost as waste heat. It is impossible to have an engine that is 100 per cent efficient. Let us now come to your specific question. If the ground was level, if friction and air resistance were eliminated you would come to the conclusion that the only energy required would be in starting and stopping! Once set in motion the body would go on moving till application of some sort of brakes stops it. This would be true whether it moved slowly or fast. The difference would lie in the fact that lot more energy would be required in taking the body up to running speed than that required for acquiring a leisurely walking pace. All this would apply to you also if the human body were a mass moving on frictionless wheels without any air resistance. But there is more to the operation of human engine. When we move fast to convert our stored energy into mechanical energy the heat increases the body temperature, which has to be kept in acceptable range through evaporation of sweat, and for longer races by water often poured over our head. That takes away a lot of energy. If you have ever watched television coverage of the great bicycle race in France you would have noticed the contestants consuming lot of water, occasionally pouring over their head. It is estimated that a bicyclist in that grueling race uses less than a quarter of his energy in overcoming friction and air resistance, the rest being lost in heat he must shed. Since you are talking of energy conservation only while humans walk, work, run or exercise I am constrained to remind you that that we also consume energy while lying down and sleeping to keep us breathing and out metabolism working. It is interesting that our brain consumes about 20 per cent energy the body uses when not doing strenuous exercise. So do not be surprised that you keep getting hungry when you are only sitting in a chair and studying for your exams. Q. What is Lorentzian and Euclidean space-time? A. We all know about Euclidean geometry. This represents the good old familiar space, where three orthogonal axes help to define the position of any point. Time is considered to be independent of space and defined independently. It is in the nature of a flowing river and believed to be the same everywhere. This picture had to be abolished when special relativity was discovered and the velocity of light in vacuum was postulated to be constant, independent of the frame of reference of the observer or the source. From then on, space could not be defined independently. It became necessary to think of a space-time in which time formed the fourth dimension. This is what one needs when momenta and energies have to be calculated in different frames of
reference. This is done through Lorentz transformation. Everything can be done in a consistent manner and at velocities much less than the velocity of light, the results are the same as in non-relativistic, Euclidean case.
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Fleeting flashAn invisible, highly energetic flash detected by a spacecraft early last week may have given astronomers their first glimpse of two neutron stars crashing together, forging a black hole at a galaxy’s edge. NASA’s Swift satellite detected the flash — a burst of gamma rays that lasted one-twentieth of a second — on May 9. Fiftythree seconds later, the craft slewed its X-ray telescope toward the same spot in the sky, fast enough to catch a rapidly fading afterglow. The X-ray detection marks the first time that astronomers have identified the location of a short-duration gamma-ray burst, which lasts less than two seconds, says Swift project scientist Neil Gehrels of NASA’s Goddard Space Flight Center in Greenbelt, Md. Extreme matter When matter was new in the universe, it was an exotic gas whose components later congealed into the more ordinary matter made of atoms. At least, that was the story. Now, physicists trying to re-create that gas in an accelerator say that the universe’s original stuff appears to have been a liquid. Like the gas that had been expected, the liquid the physicists made is ultrahot and ultradense — up to 150,000 times as hot as the sun’s core and 100 times as dense as ordinary atomic nuclei. Light therapy A new scientific era may have dawned for light therapy, a potential depression fighter that has languished in the shadows of antidepressant medication and psychotherapy for the past 20 years. A research review commissioned by the American Psychiatric Association in Washington, D.C., concludes that in trials, daily exposure to bright light is about as effective as antidepressant drugs in quelling seasonal affective disorder (SAD), or winter depression, and other forms of depression. “I now tell my patients that light therapy is a reasonable depression treatment, even if the database for this approach is relatively small,” says psychiatrist Robert N. Golden of the University of North Carolina at Chapel Hill. Golden directed the new statistical review, which appears in the April American Journal of Psychiatry. Power instead of
X-rays A painless, portable device that uses electrical current rather than X-ray to examine breasts for cancer is under study at the Medical College of Georgia. MCG is one of some 20 centres across the world studying impedance scanning, a technique based on evidence that electrical current passes through cancerous tissue more easily than normal tissue. Preliminary studies have shown the technique, which takes about 10 minutes and doesn’t require often-uncomfortable breast compression, can pick up very small tumors, according to its developers, Z-Tech, Inc., which has offices in South Carolina and Ontario. The study of some 4,500 women - about 500 at MCG Medical Center - will determine whether the device, which produces a report rather than a breast image, is accurate enough for widespread use, says Dr. James H. Craft, MCG radiologist and a principal investigator. |
