An element common to all acids is? ?->(Show Answer!)

1. An element common to all acids is?

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MCQ-> In a modern computer, electronic and magnetic storage technologies play complementary roles. Electronic memory chips are fast but volatile (their contents are lost when the computer is unplugged). Magnetic tapes and hard disks are slower, but have the advantage that they are non-volatile, so that they can be used to store software and documents even when the power is off.In laboratories around the world, however, researchers are hoping to achieve the best of both worlds. They are trying to build magnetic memory chips that could be used in place of today’s electronics. These magnetic memories would be nonvolatile; but they would also he faster, would consume less power, and would be able to stand up to hazardous environments more easily. Such chips would have obvious applications in storage cards for digital cameras and music- players; they would enable handheld and laptop computers to boot up more quickly and to operate for longer; they would allow desktop computers to run faster; they would doubtless have military and space-faring advantages too. But although the theory behind them looks solid, there are tricky practical problems and need to be overcome.Two different approaches, based on different magnetic phenomena, are being pursued. The first, being investigated by Gary Prinz and his colleagues at the Naval Research Laboratory (NRL) in Washington, D.c), exploits the fact that the electrical resistance of some materials changes in the presence of magnetic field— a phenomenon known as magneto- resistance. For some multi-layered materials this effect is particularly powerful and is, accordingly, called “giant” magneto-resistance (GMR). Since 1997, the exploitation of GMR has made cheap multi-gigabyte hard disks commonplace. The magnetic orientations of the magnetised spots on the surface of a spinning disk are detected by measuring the changes they induce in the resistance of a tiny sensor. This technique is so sensitive that it means the spots can be made smaller and packed closer together than was previously possible, thus increasing the capacity and reducing the size and cost of a disk drive. Dr. Prinz and his colleagues are now exploiting the same phenomenon on the surface of memory chips, rather spinning disks. In a conventional memory chip, each binary digit (bit) of data is represented using a capacitor-reservoir of electrical charge that is either empty or fill -to represent a zero or a one. In the NRL’s magnetic design, by contrast, each bit is stored in a magnetic element in the form of a vertical pillar of magnetisable material. A matrix of wires passing above and below the elements allows each to be magnetised, either clockwise or anti-clockwise, to represent zero or one. Another set of wires allows current to pass through any particular element. By measuring an element’s resistance you can determine its magnetic orientation, and hence whether it is storing a zero or a one. Since the elements retain their magnetic orientation even when the power is off, the result is non-volatile memory. Unlike the elements of an electronic memory, a magnetic memory’s elements are not easily disrupted by radiation. And compared with electronic memories, whose capacitors need constant topping up, magnetic memories are simpler and consume less power. The NRL researchers plan to commercialise their device through a company called Non-V olatile Electronics, which recently began work on the necessary processing and fabrication techniques. But it will be some years before the first chips roll off the production line.Most attention in the field in focused on an alternative approach based on magnetic tunnel-junctions (MTJs), which are being investigated by researchers at chipmakers such as IBM, Motorola, Siemens and Hewlett-Packard. IBM’s research team, led by Stuart Parkin, has already created a 500-element working prototype that operates at 20 times the speed of conventional memory chips and consumes 1% of the power. Each element consists of a sandwich of two layers of magnetisable material separated by a barrier of aluminium oxide just four or five atoms thick. The polarisation of lower magnetisable layer is fixed in one direction, but that of the upper layer can be set (again, by passing a current through a matrix of control wires) either to the left or to the right, to store a zero or a one. The polarisations of the two layers are then either the same or opposite directions.Although the aluminum-oxide barrier is an electrical insulator, it is so thin that electrons are able to jump across it via a quantum-mechanical effect called tunnelling. It turns out that such tunnelling is easier when the two magnetic layers are polarised in the same direction than when they are polarised in opposite directions. So, by measuring the current that flows through the sandwich, it is possible to determine the alignment of the topmost layer, and hence whether it is storing a zero or a one.To build a full-scale memory chip based on MTJs is, however, no easy matter. According to Paulo Freitas, an expert on chip manufacturing at the Technical University of Lisbon, magnetic memory elements will have to become far smaller and more reliable than current prototypes if they are to compete with electronic memory. At the same time, they will have to be sensitive enough to respond when the appropriate wires in the control matrix are switched on, but not so sensitive that they respond when a neighbouring elements is changed. Despite these difficulties, the general consensus is that MTJs are the more promising ideas. Dr. Parkin says his group evaluated the GMR approach and decided not to pursue it, despite the fact that IBM pioneered GMR in hard disks. Dr. Prinz, however, contends that his plan will eventually offer higher storage densities and lower production costs.Not content with shaking up the multi-billion-dollar market for computer memory, some researchers have even more ambitious plans for magnetic computing. In a paper published last month in Science, Russell Cowburn and Mark Well and of Cambridge University outlined research that could form the basis of a magnetic microprocessor — a chip capable of manipulating (rather than merely storing) information magnetically. In place of conducting wires, a magnetic processor would have rows of magnetic dots, each of which could be polarised in one of two directions. Individual bits of information would travel down the rows as magnetic pulses, changing the orientation of the dots as they went. Dr. Cowbum and Dr. Welland have demonstrated how a logic gate (the basic element of a microprocessor) could work in such a scheme. In their experiment, they fed a signal in at one end of the chain of dots and used a second signal to control whether it propagated along the chain.It is, admittedly, a long way from a single logic gate to a full microprocessor, but this was true also when the transistor was first invented. Dr. Cowburn, who is now searching for backers to help commercialise the technology, says he believes it will be at least ten years before the first magnetic microprocessor is constructed. But other researchers in the field agree that such a chip, is the next logical step. Dr. Prinz says that once magnetic memory is sorted out “the target is to go after the logic circuits.” Whether all-magnetic computers will ever be able to compete with other contenders that are jostling to knock electronics off its perch — such as optical, biological and quantum computing — remains to be seen. Dr. Cowburn suggests that the future lies with hybrid machines that use different technologies. But computing with magnetism evidently has an attraction all its own.In developing magnetic memory chips to replace the electronic ones, two alternative research paths are being pursued. These are approaches based on:
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MCQ-> Throughout human history the leading causes of death have been infection and trauma, Modem medicine has scored significant victories against both, and the major causes of ill health and death are now the chronic degenerative diseases, such as coronary artery disease, arthritis, osteoporosis, Alzheimer’s, macular degeneration, cataract and cancer. These have a long latency period before symptoms appear and a diagnosis is made. It follows that the majority of apparently healthy people are pre-ill.But are these conditions inevitably degenerative? A truly preventive medicine that focused on the pre-ill, analyzing the metabolic errors which lead to clinical illness, might be able to correct them before the first symptom. Genetic risk factors are known for all the chronic degenerative diseases, and are important to the individuals who possess them. At the population level, however, migration studies confirm that these illnesses are linked for the most part to lifestyle factors — exercise, smoking and nutrition. Nutrition is the easiest of these to change, and the most versatile tool for affecting the metabolic changes needed to tilt the balance away from disease.Many national surveys reveal that malnutrition is common in developed countries. This is not the calorie and/or micronutrient deficiency associated with developing nations (type A malnutrition); but multiple micronutrient depletion, usually combined with calorific balance or excess (Type B malnutrition). The incidence and severity of Type B malnutrition will be shown to be worse if newer micronutrient groups such as the essential fatty acids, xanthophylls and falconoid are included in the surveys. Commonly ingested levels of these micronutrients seem to be far too low in many developed countries.There is now considerable evidence that Type B malnutrition is a major cause of chronic degenerative diseases. If this is the case, then t is logical to treat such diseases not with drugs but with multiple micronutrient repletion, or pharmaco-nutrition’. This can take the form of pills and capsules — ‘nutraceuticals’, or food formats known as ‘functional foods’, This approach has been neglected hitherto because it is relatively unprofitable for drug companies — the products are hard to patent — and it is a strategy which does not sit easily with modem medical interventionism. Over the last 100 years, the drug industry has invested huge sums in developing a range of subtle and powerful drugs to treat the many diseases we are subject to. Medical training is couched in pharmaceutical terms and this approach has provided us with an exceptional range of therapeutic tools in the treatment of disease and in acute medical emergencies. However, the pharmaceutical model has also created an unhealthy dependency culture, in which relatively few of us accept responsibility for maintaining our own health. Instead, we have handed over this responsibility to health professionals who know very little about health maintenance, or disease prevention.One problem for supporters of this argument is lack of the right kind of hard evidence. We have a wealth of epidemiological data linking dietary factors to health profiles/ disease risks, and a great deal of information on mechanism: how food factors interact with our biochemistry. But almost all intervention studies with micronutrients, with the notable exception of the omega 3 fatty acids, have so far produced conflicting or negative results. In other words, our science appears to have no predictive value. Does this invalidate the science? Or are we simply asking the wrong questions?Based on pharmaceutical thinking, most intervention studies have attempted to measure the impact of a single micronutrient on the incidence of disease. The classical approach says that if you give a compound formula to test subjects and obtain positive results, you cannot know which ingredient is exerting the benefit, so you must test each ingredient individually. But in the field of nutrition, this does not work. Each intervention on its own will hardly make enough difference to be measured. The best therapeutic response must therefore combine micronutrients to normalise our internal physiology. So do we need to analyse each individual’s nutritional status and then tailor a formula specifically for him or her? While we do not have the resources to analyze millions of individual cases, there is no need to do so. The vast majority of people are consuming suboptimal amounts of most micronutrients, and most of the micronutrients concerned are very safe. Accordingly, a comprehensive and universal program of micronutrient support is probably the most cost-effective and safest way of improving the general health of the nation.The author recommends micronutrient-repletion for large-scale treatment of chronic degenerative diseases because
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MCQ-> Read the following passage carefully and answer the question given below it. Certain words/phrases have been printed in bold to help you locate them while answering some of the questions. There was a country long time ago where the people would change a king every year. The person who would become the king had to agree to a contract that he would be sent to an island after one year of his being a king. One King had finished his term and it was time for him to go to the island and live there.The people dressed him up in expensive clothes and put him on an elephant and took him to around the cities to say goodbye to all the people. This was a moment of sadness for all kings who ruled for one year. After bidding farewell the people took the king to a remote island in a boat and left him there. On their way back they discovered a ship that had sunk just recently.They saw a young man who survived by holding on to a floating piece of wood. As they needed a new king, they picked up the young man and took him to their country. They requested him to be king for a year. First he refused but later he agreed to be the king. People told him about all the rules and regulations and about how he would be sent to an island after one year. After three days of being a king he asked the ministers if they could show him the island where all the other kings were sent. They agreed and took him to the island. The island was covered with a thick jungle and sounds of vicious animals were heard coming out of it. The king went a little bit further to check. Soon he discovered dead bodies of all the past kings.He understood that as soon as they were left on the island the wild animals had come and killed them. The king went back to the country and collected 100 strong workers. He took them to the island and instructed them to clean the jungle, remove all the deadly animals and cut down all excess trees. He would visit the island every month to see how the work was progressing. In the first month all the animals were removed and many trees were cut down. In the second month all the island were cleaned out. The king then told the workers to plant gardens in various parts of the island. He also took with himself useful animals like chickens, ducks, birds, goats,cows etc. In the third month he ordered the workers to build big house and docking stations for ships. Over the months the island turned into a beautiful place. The young king would wear simple clothes and spend very little from his earning as a king. He sent all the earnings to the island for storage. When nine months passed like this the king called the ministers and told them “I know that I have go to the island after one year but I would like to go there right now. But the ministers didn’t agree to this and said that he had to wait for another three months to complete the year. Three months passed and now it was a full year. The people dressed up the young king and put on an elephant to take him around the country to say goodbye to others. However this king was unusually happy to leave the kingdom. People asked him "All the other kings would cry at this moment. Why is it that you are laughing?". He replied “Don’t you know what the wise people say? They say that when you come to this world as a baby you are crying and everyone else is smiling. Live such a life that when you die you will be smiling and everyone around you will be crying. I have lived that life. While all the other kings were lost into the luxuries of the kingdom, I always thought about the future and planned for it. I turned the deadly island into a beautiful abode for me where I can stay peacefully”.Why did the people of the kingdom change the king every year ?
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MCQ-> A passage is given with five questions following it. Read the passage carefully and select the best answer to each question out of the given four alternatives.Superstitions are a universal phenomena having their own peculiar place in the cultural ethos and milieu of a people. They epitomize man's fear of the unknown, fear of evil, blind faith in omens and portents. Superstitions are inter-woven with myth, legend, unnatural phenomena and disaster, customs and traditions, and are mainly the outcome of ignorance. They are unreasoned and irrational beliefs that gradually become matters of faith. When certain things and happenings are rationally inexplicable people tend to assign mysterious and supernatural reasons for their operation. Thus a natural disaster is explained in terms of God's wrath and the failure of one's project is assigned to the black cat which crossed the path just as one set out on the errand. The primitive human beings were mainly governed by superstitions. Superstitions were widespread before the dawn of civilization when science had not advanced. Thus, ignorance of the primitive people and the resultant growth of superstitions were the direct outcome of the lack of scientific advancement. Unenlightened people always tend to be superstitious. The belief in the sanctity of time and old traditions of the ancestors bind the people into knots of superstitious thought. Besides, the unscrupulous priests and religious officials exercise a dominating, unhealthy effect upon the people believing in religious orthodoxy. They encourage superstitions for their own ulterior motives. Superstitions are not only universally prevalent but even have strikingly common features whether believed in India or in as far off a place as Canada. There are some common superstitions which are shared by people all over the world. Beliefs in spirits, ghosts and witches and reincarnation are quite common among all the peoples of the world. Belief in witches still prevails in India, France, Scotland, England and many other countries. In countries of the East, especially in India, belief in ghosts and spirits still exists. The cries of certain birds like owls and ravens and the howl of cats are regarded with superstition as portents of evil throughout the world. Then there is a very common belief that the sighting of comets portends the death of kings or great men or some unforeseen catastrophe. Shakespeare refers to such a superstition in his Julius Ceaser, Halley's Comet in the twentieth century evoked a similar response in many a mind.What is the main reason behind once superstitions?
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MCQ->A 2-terminal network consists of one of the RLC elements. The elements is connected to an ac supply. The current through the element is 1 A. When an inductor is inserted in series between the source and the element, the current through the element becomes 2 A. What is this element?....