UPSC

Formerly people used to write on the leaves of certain trees. Palm leaves were then used for this purpose. Paper is a very useful thing now. It is used for writing letters, bills and legal documents. No office or school can do without paper. It is used in blotting ink, in wrapping up parcels and in decorating the walls of our rooms. Ancient people could not spread knowledge so easily because there was no paper or printing press. Paper is a very useful thing. It is made of rags, old papers, grass etc. These things are reduced to dust in a paper mill. It is then boiled. It becomes something like a thick solution, called pulp. Pulp is then purified. Then it is made white by bleaching. Sometimes, some dye is mixed with pulp and it becomes coloured. Thus we get red, blue, green or yellow paper. Pulp is spread more...

It was a fine day I decided to spend the evening at Connaught Place. I got ten rupees from my father. 1 left my house at 6 p.m. to catch the bus for Odeon. I stood in the queue and waited anxiously for my turn in vain. Joined those who were  struggling on the door of the bus. With a great difficulty I also got my chance to get into the bus. I got a seat. Hardly had I sat on my seat when 1 saw a very old man. He was standing near me. He looked very sad. I looked at him. I got up out of respect. 1 offered my seat to him. But to my great surprise, a fashionable young lady rushed towards the seat. She pressed herself into the seat. The poor old man looked at her helplessly. He had to keep standing. The lady felt more...

Chemotherapy's effectiveness against cancer was discovered from mustard gas, a lethal weapon used in the World War I trenches. Autopsy observations of soldiers exposed to the gas revealed destruction of lymphatic tissue and bone marrow. Scientists at the time reasoned that mustard gas might destroy cancer cells in lymph nodes, but nothing was done. Early in 1942 Alfred Gilman (1908-1984) and Louis S. Goodman (1906-2000), two pharmacologists at Yale University, were recruited by the U.S. Department of Defense to  investigate  potential  therapeutic applications of nitrogen mustard (a derivative of mustard gas) on lymphoma. After establishing lymphomas in mice and rabbits, they went on to show that they could treat them with mustard agents. The- next step was to inject mustine (the prototype anticancer agent) into a patient with non-Hodgkin's lymphoma, whose cancer had become resistant to radiation. Initially the patient responded well, with doctors noting a softening of the tumor more...

When, in 1958, fifteen-year-old Bobby Fisher became the youngest Grandmaster in chess history, few onlookers would have believed that, one day, a machine would be capable of beating him. After the invention of the transistor, electronic equipment became ever more complex. Thousands of different sized components had to be soldered together to make the circuits and were being crammed into less and less space. This was time- consuming, expensive, and unreliable. The Micro- Module program undertaken by the U.S. Army's Signal Corps made pre-wired building block components of a standardized size that could be snapped together. This still did not solve the core problem, however. Texas Instruments were working with the Micro- Module project when Jack Kilby joined them in 1958. Before long he saw a better solution. As passive components such as capacitors and resistors could be made from the same semiconductor material as active devices such. as transistors, more...

The fact that the current passing through a wire conductor produces a magnetic field around the wire, and that two current-carrying wires could attract or repel each other depending on the direction of the current, was emphasized in 1820 by the independent writings of Hans Oersted and Andre-Marie Ampere (after whom the Sl unit of measurement of electric current, the ampere, is named). It was, however, William Sturgeon (1783-1850), a physicist working at the Royal Academy, Woolwich, London, who recognized the significance of the phenomenon. He converted electromagnetic devices from toys into practical weightlifting machines. A horseshoe of iron around which is wound a loose current-carrying coil becomes a strong metal-lifting device when the current is switched on and, just as important, the force disappears when the current is switched off. The action of the device can be speedily controlled by electricity. Electricity can flow down miles of wire, so more...

Onam is the most typical Kerala festival which has now earned an all-India character. It coincides with harvest season and is an occasion of spontaneous revelry. Onam celebrates home coming of Mahabali, legendary kind, who ruled over Kerala in an age of plenty but was pushed down to infernal regions by Vishnu in the form of Vamana. It is now celebrated as a national festival under government auspices. Onam comes on the Shravan Bhadrapada in the month of Shravan according to the Hindu lunar calendar around August or September. On this occasion, people clean their houses and their surroundings and decorate it beautifully.  They start their preparations a few days before the festival. Two little mounds of earth are placed in the centre to represent king Mahabali and Lord Vishnu.  There is a favour of festivity all around. Ladies prepare floral rangolis with beautiful designs at the entrance of their more...

"You can't keep changing your men, so you settle for changing your lipstick." Heather Locklear, American actress Women have added color to their lips for at least five millennia. The earliest evidence of a colored paste or lipstick comes from Mesopotamia in around 3000 B.C.E. There, it was made of crushed semi-precious Jewels and then put on to the eyelids as well as the lips. Cleopatra, Pharoah of Egypt (69-30 B.C.E.) used crushed carmine beetles in a base made of ants as lipstick. Some formulations would have resulted in serious illness or even death, such as the Ancient Egyptian concoction from 1400, B.C.E., which used a red dye extracted from seaweed, mixed with iodine and toxic bromine compounds. In 1915, Maurice Levy invented the sliding tube that we know as lipstick. Levy's tubes were just 2 inches (5 cm) long. The sliding tube worked by a set of slide levers more...

Imagine inventing a process that made a task 3,000 times faster than it used to be, not to mention substantially less dangerous and labor intensive. Now imagine that process as the key to unlocking and mapping the human genome. That is what Leroy Hood (b. 1938) and Lloyd Smith (b. 1954) did in 1985 when they invented automated DNA seguencing. DNA seguencing was initially invented in the 1970s, but it involved a long, laborious process in which the nucleotide base pairs that make up DNA were tagged radioactively and then attached to existing single strands of DNA. The resulting strands of DNA were run through a separation gel and painstakingly examined manually, base pair by base pair, strand by strand, and the seguence recorded by hand. Hood and Smith recognized that this process was at best impractical, and along with their colleagues Tim and Michael Hunkapillar set out to streamline more...

A persons is rags who pulls a rickshaw is called rickshaw puller. He is often seen here and there on the road, in market complexes, near cinema halls, schools, hospitals etc. He belongs to the poor class of our society and serves to the humanity whether it is rain or its chilli cold or it is scorching heat. He is ready to give his service all the time.  A rickshaw puller leads a very hard life. He earns little to meet two square meals a day for his family. He never cares for his health and pulls his rickshaw for maximum hours in a day. Apart from carrying person or persons, he carries goods like vegetables, tea and other things in the form of packed or unpacked bundles. Nowadays some rickshaw pullers are seen engaged in carrying school children. It gives them a permanent income. And what is more, they more...

"The Good God, Golden [Horus], Shining in the chariot, like the rising of the Sun..." Tablet of victory of Amenhotep III (1391-1353 B.C.E) The development of the spoked-wheel chariot circa 2000 B.C.E revolutionized warfare. Bronze tools allowed carpenters to discard the solid, heavy, planked wheel in favor of a lighter, spoked wheel. This was made by placing a set of same-length spokes around a central hub and then fixing them within a wooden, circular rim, itself held together by an outer bronze band. Spoked wheels were larger and lighter than their predecessors and ran better over uneven ground. Used on a two-wheeled chariot that was pulled by a single horse and driven by a charioteer, with room for a warrior alongside, the charioteer could now easily outpace the foot soldier while the warrior—with the advantage of speed and maneuverability—attacked him with spear, lance, or bow. The use of such chariots more...