Delhi State Exams

"Prozac® enjoyed [a] career of renown... rumors... scandal... and finally a quiet rehabilitation." Peter D. Kramer, Listening to Prozac (1993) Prozac® is the registered trademarked name for fluoxetine hydrochloride, the world's most widely prescribed antidepressant. It was the first in a new class of drugs for depression called selective serotonin re-uptake inhibitors (SSRIs), which work by increasing brain levels of serotonin, the neurotransmitter thought to influence sleep, appetite, aggression, and mood. Prozac® works by inhibiting re-uptake of the neurotransmitter (where it-is either destroyed or retrieved into the cell), thereby amplifying its levels. At Eli Lilly and Company, the team of inventors behind Prozac® included Bryan Molloy Ray Fuller, and David Wong. In the early 1980s it was known that the antihistamine diphenhydramine showed some antidepressant-like properties. As a starting point, the team took 3-phenoxy-3-phenylpropylamine (which is a compound structurally similar to diphenhydramine) and synthesized dozens of its derivatives. Fluoxetine hydrochloride more...

Coffee is a very popular drink for the rich people of the world. In our country, it is very popular in South India. Warm and moist climate is favourable for coffee cultivation. Good rainfall throughout the year is also necessary. In India, coffee grows in large quantities in the hilly areas of southern states like Karnataka, Kerala and Tamil Nadu. A coffee plant is usually 3 to 6 metres tall. A cluster of berries grows in the plant. Each berry contains two seeds. These seeds are roasted and powdered in the factory through different processes. The drink is made by mixing powder coffee with hot milk, water and sugar. It is very refreshing and tasty.           

"[In] 1974, the first product with a barcode [chewing gum] was scanned at a checkout counter." Russ Adams, author The development of barcodes stemmed from comments made by a food-chain president to a university dean at the Drexel Institute of Technology, Philadelphia, in 1948, and overheard by graduate student Bernard Silver (1924-1962). The company wanted some sort of system to collect product information at the checkout automatically, but the dean had little interest in initiating such research. Silver decided that he and his friend Norman Woodland (b. 1921) should pursue a solution. Eventually the pair turned to a combination of movie soundtrack technology invented by Lee De Forest in the 1920s and Morse code dots and dashes; "I just extended the dots and dashes downward and made narrow lines and wide lines out of them," said Woodland. De Forest's film included a varying transparency pattern on its edge. When a more...

For thousands of years, men have been using specially created tools to shave facial hair. Sharpened, razorlike objects carved from metal or obsidian (a glasslike substance found in rock) have been found in Bronze Age sites across the globe. By the end of the nineteenth century, the straight, "cutthroat" razor was the most common shaving tool. These had dangerously sharp blades that required skill to use without cutting the skin. They also had to be constantly sharpened to remain effective. The first safety razor with a guard along the razor's edge was introduced in 1875 by the Kampfe brothers, but the blade still needed frequent sharpening. Astute American businessman King Camp Gillette (1855-1932) realized that if he could create a safe and simple shave without the inconvenience of having to sharpen the blade beforehand, his product could be of interest to every adult male in the world. His idea was more...

Pratibha Patil, a woman of Maharashtrian origin, has been elected as the 13th President of India. She has made history by becoming the first woman President in the history of India.  Smt. Patil was born on 19th December, 1934inNadgaonofMaharashtra. Her father was Narayan Pagloo Rao. She got her school education at R.R. School, Jalgaon. Thereafter she got the M.A. degree from Mooiji Jaitha (M.J.) College, Jalgaon which was an affiliated unit to North Maharashtra University, Jalgaon. Then she obtained her degree in law from the Government Law College, Mumbai an affiliated unit of the University of Bombay. During her college days she excelled in the table tennis and won various inter-college tournaments. In 1962 she was voted 'College Queen' of M.J. College. In the same year she began her political career by winning an assembly election from Ediabad Assembly Constituency on the Indian National Congress ticket. She was married to more...

Charles Drew (1904-1950) is widely credited as the father of the modern blood bank. In 1937, Drew made the key discovery that separating red blood cells from the plasma (the liquid part of blood that can be given to anyone), and freezing the two separately, allowed blood to be preserved for longer and reconstituted at a later date. In February of 1941, Drew was appointed director of the first American Red Cross Blood Bank, and launched the "Plasma for Britain Project" where he collected thousands of units of plasma for the British war effort. From these samples the British Army established its own blood transfusion service, where dried and powdered plasma could be stored and turned into a liquid with the addition of sterile, distilled water. After the war, doctors who had seen the effectiveness of transfusion therapy in battle began to demand that blood be made available for treatment more...

The earliest lenses were made of circular pieces of rock crystal or semiprecious stone, such as beryl and quartz, which were ground and polished so that they produced a magnified image when looked through. The oldest known lens artifact was one made of rock crystal dating from around 640 B.C.E. and excavated in Nineveh, near the modern city of Mosul, Iraq. The most common form was circular and thicker in the middle than around the edge, and having both its front and back surfaces the same shape. The modern convex lens developed from the ancient Greek burning glass. Here a spherical vase of water would be used to concentrate the rays of the sun onto a small area, which heated up. The heat was used to ignite fires in temples or to cauterize wounds. The Iraqi mathematician and optics engineer Ibn Sahl (c 940-1000) wrote the treatise On Burning Mirrors more...

The neighbour is the nearest person with whom one has social contact. He can render his services at the time of need. They are partners in one's sorrows and joys. Having a good neighbour is a blessing and a bad neighbour is a curse. This is our good luck that our neighbours are decent. Our nearest neighbour is Mr. Agnihotri. His house is next to ours. He has good manners and a very sweet nature. We always find him with a smiling face. He has three sons and a daughter. Every member of his family is cultured and good mannered. You will never find them quarrelling with others. They are always ready for any type of help to their neighbours. Mr. Agnihotri's daughter who is a B. Corn first year student is always ready to solve the problems of the children of their neighbours In the entire colony she is more...

The Pitot (pronounced pea-tow) tube is an eighteenth- century invention still flying high amid twenty-first- century technology. Designed by French astronomer, engineer, and mathematician Henri Pilot (1695-1771), this deceptively simple device is essentially a differential pressure gauge and can be used for a variety of flow-rate or speed-measuring purposes. Pitot's pet interest was water flow, and his personal research led him to conclude that much of the accepted wisdom of the day was incorrect. He would not accept, for example, the prevailing theory that, other things being equal, the speed of flowing water increased with depth. His tube, demonstrated at the French Academy of Sciences in 1732, would show that he was right: it does not. As well as being used in a fixed position to determine the flow rate of a liquid or gas the  L-shaped tube may be attached to a boat or airplane to measure the craft's more...

Games and sports are an important part of education. In the past there was no provision for them in Indian schools and colleges. But now no educational institution is complete without some arrangement for different games and sports.  Games and sports have many advantages. They improve health and help in building up a good body. As games are played in the open air. the body gets plenty of sunshine and fresh air. The value of good health is well expressed in the proverb-"A sound mind in a sound body". Hockey, football and other games provide better health than walks can. Games have another advantage. They develop a spirit of comradeship. Students do not play for themselves only but for the team as a whole. Thus a sportsman develops a broad outlook and learns the value of co-operative work. These habits prove highly useful in life. Besides comradeship games provide good more...