Sahara

The largest of all deserts is sahara. This vast
sunbaked land of barren rock, gravel, and shifting sand stretches across northern Africa. Burning sun and scorching winds make it the hottest region in the world in summer. Palm trees and crops can be grown only where there is a spring, a well, or a stream. These fertile spots are called oases (singular, oasis).
The name Sahara comes from the Arabic word sahara, meaning “deserts.” Almost as large as the entire United States, the Sahara covers 3.5 million square miles (9 million square kilometers). It extends some 3,000 miles (4,830 kilometers) from the Atlantic Ocean to the Red Sea. Southward it spreads an average of 1,000 miles (1,600 kilometers) to the region of the Niger River and Lake Chad in the Sudan. The great desert contains at least a part of Western Sahara, Mauritania, Morocco, Algeria, Tunisia, Mali, Niger, Chad, Libya, Egypt, and The Sudan.
The Sahara is one of the Earth's low-latitude deserts that extend inland from west coasts in and near the tropics. The dry winds that blow over the hot land seldom drop rain except where mountains force the air upward, thus cooling it. Elsewhere rain falls only when a powerful cyclonic storm invades the region, bringing a downpour. In some areas such storms occur only once in ten or more years.
The cloudless sky and dry air expose the land to the piercing tropical sun. A sandy surface may have a temperature of 170°  F (77°  C) or more. In July the air temperature is more than 100°  F (38°  C) in many places. The land cools rapidly when the sun sets. Temperatures may drop as much as 30°  to 50°  F (17°  to 28°  C). In winter they may fall below freezing in the north. Ice forms at night.
During the hot days the wind raises little whirlwinds of dust, called “waltzing jinns.” At times a furious, dust-laden wind, called the simoom, sweeps the land.
The Ahaggar Mountains overlook a barren landscape in the central Sahara, in southern Algeria.
Much of the Sahara is a series of plateaus. They average 1,000 feet (300 meters) in altitude. Across it from southeast to northwest runs a broad, rocky ridge. This chain reaches its greatest general elevation in the central Sahara, forming the Ahaggar mountain mass. The highest mountains, however, rise in the Tibesti group to the east. Here is the extinct volcano Emi Koussi, the Sahara's highest elevation at 11,204 feet (3,415 meters).
In the Sahara are various surface formations common to most deserts. Here are rocky uplands, called hammadas, broad stretches of gravel, sand dunes, and basins filled with drifting sand, called ergs. Though the dunes are the most picturesque feature, they occupy only about one eighth of the area. Travel routes avoid them. The Libyan Erg near Egypt holds the greatest mass of dunes on Earth. It covers an area as large as France. The hot sand may give rise to the scorching Egyptian khamsin wind.
The Nile and the Niger rivers cross the edges of the Sahara. There are no other permanent streams. Dry streambeds, called wadis, seam the desert. Travelers are warned against camping in them, however, because the beds may fill with torrents of water during the rare downpours. Some wadis mark the course of underground streams. Vegetation fringes these courses where the water table is near enough to the surface to be reached by plant roots. An oasis develops where the water supply is sufficient to support substantial plant growth.
In the northwestern Sahara, at the base of the Atlas Mountains, runs a narrow strip of green oases. It extends southeast 750 miles (1,207 kilometers) to the foothills of the Ahaggar. Another depression, the Fezzan, lies between the Ahaggar and Tibesti mountain groups, in the southwestern section of Libya.
Despite its dryness, the Sahara has scattered plant and animal life. Shrubs and other plants resistant to evaporation send their long roots toward underground water, and coarse grass grows in widely separated bunches. Soon after the rare rains, a carpet of delicate, quick-blooming flowers is spread
Mammal species found in the Sahara include the gerbil, desert hedgehog, and other rodents; the aoudad, or Barbary sheep, the Dorcas gazelle, and the Nubian wild ass; the anubis baboon; the spotted hyena; the pale fox, or African sand fox; and the Libyan striped weasel and slender mongoose. The more than 300 bird species found there include water and shore birds in coastal zones and along waterways, and ostriches, owls, eagles, ravens, and guinea fowl in the interior. Frogs, toads, and crocodiles inhabit the lakes and pools of oases. Lizards and cobras live among the rocks and dunes. Desert snails may remain dormant for years between reviving rainfalls.

Prehistoric Past
The Sahara was not always a parched desert as it is today. Throughout the Ice Age, the huge glaciers and ice caps of Europe pushed the zone of temperate climate southward. The Sahara was then a rich grassland and hunting ground for prehistoric people. Relics of these people include stone tools and rock carvings on sheltered cliffs and walls of caves.
These early inhabitants of the region may have been the ancestors of the Berber people of northern Africa. The Berbers are an ethnic group of people who inhabited North Africa prior to the invasion and settlement of the area by Arabs in the 7th century AD. After the invasions, many Berbers were converted to Islam and assimilated into Arab society. Today, the Berbers live in tribes scattered across the countries of North Africa. The various tribes speak distinct languages—however, all of the Berber tongues are more closely related to ancient Egyptian than to Arabic. Many Berbers speak Arabic as well.
By early ancient times, the Sahara was dry and hot as it is today. The northern coastal strip supported warlike people who made trouble for their neighbors. Raiders from the Libyan Desert invaded Egypt. The Carthaginians, and later the Romans, had to keep a watchful eye on the Numidians, who inhabited an area roughly correspondent to that of present-day Algeria.
The vast desert barred travel to central Africa. During the days of the Roman Empire, however, people learned to use the camel for desert travel. Berbers from the Mediterranean coast filtered southward. They improved irrigation systems and planted date palms. Arabs with long camel caravans crossed the Sahara to collect ivory and gold, animal skins, and ostrich feathers. They also imported slaves from central Africa.
The camel provided a perfect mount for the Tuareg, a pastoral Berber people who dominated much of the central Sahara. Before the arrival of Europeans, the raiding of caravans and travelers was an important means of acquiring goods. The Tuareg also traded with merchant caravans, but the number of these caravans declined as motor vehicles became available. In the late 20th century increasing urbanization and the occurrence of devastating droughts across the savannas bordering the southern Sahara led many Tuareg to abandon their traditional livelihoods of raising and herding livestock.

How People Live in the Sahara
Some of the people who live in the Sahara raise crops on irrigated land in an oasis. Others tend flocks of goats, sheep, and camels. These herders find grass for the stock along the desert's fringe or where sudden rains have fallen. They live in tents so they can move easily as soon as the grass is eaten in one place.
The nomads wear long woolen robes called barracans for protection against the hot sun and stinging sandstorms. They wear turbans wound around the head and neck and sandals to guard their feet on the hot ground. They eat dates from oasis palms and cheese made from the milk of goats and camels. Water is a scarce and precious resource. In the markets of the oasis villages people trade wool, hides, and some of their animals for dates, coffee, and manufactured articles
Through the centuries palm-shaded oases have been ports of call for thirsty caravans. Here they made stops to rest, pasture, and water their camels. Many oases grew into fortified villages. The larger ones have a citylike appearance, with narrow, roofed-over streets and buildings several stories high.
The spread of modern transportation increased after World War II, when the French began exploring and developing the petroleum and gas resources of Algeria. Pipelines were laid to carry the oil to Mediterranean ports. Caravan trails were changed into roads covered with a tar that withstands the heat. Four such roads cross the desert from north to south. Airports were built at the chief oasis towns and at oil and gas fields. In the late 20th century increased urbanization and devastating droughts across the southern Saharan savannas led many Tuareg to abandon their traditional pastoral lifestyles.

Modern Developments
The discovery of petroleum and natural gas reserves in Algeria attracted international interest in exploring and developing the Sahara. Soon other oil and natural gas fields were discovered in Egypt and Libya, and large deposits of such minerals as iron ore, copper, and manganese were found as well. Uranium is widely distributed in the Sahara and has been particularly important in Niger.
In 1960 France began testing nuclear weapons in the Algerian desert. After protests from African nations, the test site was abandoned. An agreement for Algerian independence, signed on March 18, 1962, included arrangements for joint control over Algerian oil fields and a split of the profits from all petroleum sales. There was large-scale development and population expansion of the Sahara in the 1960s.
A severe drought in the late 1960s and early 1970s, caused by vastly increased numbers of livestock and their subsequent overgrazing of the land, devastated the region's economy. Agricultural programs implemented in the 1980s at the Sabha and Al-Kufrah oases in Libya produced good crops of wheat and fruits.

Cactus

The plants known as cactuses, or cacti, are well suited for life in the desert. Their unique ability to store water allows them to flourish in arid conditions in which other plants could not survive. The cacti are flowering plants that belong to the scientific family Cactaceae, which includes some 1,700 species.
Cacti are native through most of North and South America, but they grow chiefly in the dry regions of the southwestern United States, Mexico, Central America, and southern South America. A few species are found in tropical or subtropical areas of the world such as East Africa, Madagascar, and Sri Lanka. The plants may have been introduced to these areas. Most cacti grow in the ground, but several tropical species are epiphytes, growing on other plants. Others live on hard substances such as rocks.
Cacti are characterized by their adaptations to the harsh environments in which they live. Ordinary nondesert plants take up water from the soil by means of their roots and give off water through their leaves. This process is called transpiration . A cactus has no leaves or only very small ones that usually drop off as the plant matures. The cactus thus avoids a huge loss of water. The stem is fleshy and thick and can store a large amount of water. Its tough skin keeps the water safely hoarded. Photosynthesis occurs on the green surface of the stem. Cactus roots do not extend deep into the soil like those of other plants; instead they spread out near the surface. This enables the plant to absorb water from a wide area during the infrequent, light rains that occur in the desert.
With few exceptions, cacti bear tough, sharp spines. These spines help protect the plant from many desert-dwelling animals. The spines grow from small cushionlike tissues called areoles that are arranged in patterns on the surface of the plant.
Barrel cactus.The many types of cacti vary widely in appearance. One of the most impressive species is the saguaro of Mexico, Arizona, and California, which may grow to a height of 50 feet (15 meters). Its stem and branches are like great spiny columns up to 2 feet (about 0.6 meter) thick. It has large white flowers and bears red, edible fruit. The common cacti known as prickly pears have round, flat stems and branches and yellow or reddish flowers. Their name refers to the edible, pear-shaped fruit produced by some species. Barrel cacti look like spiny barrels or globes and may reach a height of 10 feet (3 meters). The buttonlike peyote cacti have a spineless, soft body that is only 2 inches (5 centimeters) tall. Among the most beautiful cacti is the night-blooming cereus. Its waxlike blossoms open only for one night and wither when sunlight appears.
Cacti reproduce sexually, through the process called pollination. The male part of a cactus flower produces a substance called pollen, which must be transferred to the female part of the flower for fertilization to occur. The result is a seed, which may develop into a new plant.
Many unique varieties of cacti are prized as houseplants. As a consequence many rare species have been overcollected and some face extinction. Other types of cacti have been grown for their fruit or even as living fences. Peyote, known for its hallucinogenic effects, has been used in Native American ceremonies.

ANGAS SCOTT

Charlotte Angas Scott was born in England. Her father, Caleb Scott, was president of Lancashire College, a Congregational minister and known as a social reformer; his father had been a reformer as well. Caleb Scott urged his daughter, Charlotte Angas Scott, to seek a university education, unusual for women in that time. She did so: she joined ten other young women at Hitchin College, soon renamed Girton College, part of Cambridge University.
As a pioneer in women's higher education, Charlotte Angas Scott and her classmates faced severe restrictions and on their participation and activities. Not officially permitted to take the traditional oral exam at the end of Cambridge's program, Charlotte Scott took it unofficially -- and placed eighth in the ranking overall, including all male students. At the awards ceremony, the women's names were not included in the rankings read. But male students shouted "Scott of Girton!" over the name of the male student who was announced in the eighth place.
Charlotte Angas Scott went on, then, to graduate studies at the University of London while serving as a lecturer at Girton. In 1885, she moved to the United States to join the first faculty of the newly-founded Bryn Mawr College in Pennsylvania, the first women's college offering graduate degrees.
At Bryn Mawr, Charlotte Angas Scott promoted strict entrance policies and her efforts eventually led to the founding of the College Entrance Examination Board. Scott was the first chief examiner of the Board.
In 1909, Charlotte Scott was given the first endowed chair at Bryn Mawr, in recognition of her achievements.
Charlotte Angas Scott was a member of the council that transformed the New York Mathematical Society into the American Mathematical Society in 1895, and she served as the society's vice president in 1905. She was coeditor of the American Journal of Mathematics in 1899, and continued editing for that journal until her retirement. When arthritis forced a hiatus from publishing, Charlotte Scott took up gardening and bred a new chrysanthemum.
Charlotte Angas Scott never married, though she often visited with her relatives in England (where she was known as "Aunt Charlie"), and she also frequently visited her friend Frank Morley in Baltimore.
Charlotte Scott retired in 1925, though she remained at Bryn Mawr for a few more years until her last doctoral student had graduated. She died in England in 1931.
Works
1894: An Introductory Account of Certain Modern Ideas and Methods in Plane Analytical Geometry. First edition, 1894. Second edition, 1924. Third edition published in 1961 as Projective Methods in Plane Geometry.
1899: "A Proof of Noether's Fundamental Theorem"
1907: Cartesian Plane Geometry, Part I: Analytical Conics

ELENA CORONA PISCOPIA

(June 5, 1646 - July 26, 1684) mathematician, philosopher(Elena Lucrezia Cornaro Piscopia)first woman to earn a doctoral degree
The Cornaro family of Venice traced its heritage back to the Roman family of Cornelii. Ancestors included cardinals and popes. The castle Piscopia was given to the family by the husband of a (related) queen of Cyprus.
Elena Cornaro Piscopia was born in 1646 into this family. Her father was a public official who educated his children personally. A parish priest recognized Elena as a child prodigy when she was seven, and then she began to study with tutors in Latin, Greek, music, theology, and mathematics. She eventually learned Hebrew, Arabic, Chaldaic, and also French, English, and Spanish. She studied philosophy, and astronomy. Musically talented, by the time she was 17 years old she could sing, compose, and play such instruments as the violin, harp, and harpsichord.
Her achievements attracted the attention of many, including clerics, royals, and scientists. Many came to Venice to meet and speak with her.
Elena herself wanted to enter the Benedictine Order. She secretly practiced the disciplines of the Order and turned down marriage proposals, spending time serving the sick and the poor. But her father refused permission for her to enter the Order, and had her apply instead to the University of Padua.
Although some other women had studied science and math at the university level in Italy in her time, Elena Piscopia was the first to apply in theology. She studied there from 1672-1678, and in 1678; she received her master's and doctorate of philosophy degrees. The ceremony awarding her these degrees had to be held in the cathedral to accommodate the crowd that came to see her receive them.
Elena Piscopia became a lecturer in mathematics at the University, where she served until her early death in 1684.
She was honored after her death as a woman of learning. The University of Padua has a marble statue of her. Vassar College in New York has a stained glass window depicting her achievement.
Her achievement did not immediately open doors for many others, though. No other woman earned a doctorate at the University of Padua until the late twentieth century.

MAGNA CARTA
A basic document that states the liberties guaranteed to the English people, the Magna Carta proclaims rights that have become a part of English law and are now the foundation of the constitution of every English-speaking nation. The Magna Carta, which means “great charter” in Latin, was drawn up by English barons and churchmen, who forced the tyrannical King John to set his seal to it on June 15, 1215
King John's cruelty and greed united the powerful feudal nobles, the churchmen, and the townspeople against him. While the king was waging a disastrous war in France, the leading barons of England met secretly and swore to compel him to respect the rights of his subjects. When John returned, they presented him with a series of demands. John tried to gather support in order to avoid giving in to the demands, but almost all his followers deserted him. At last he met with the nobles and bishops along the south bank of the Thames in a meadow called Runnymede and affixed his seal to the Magna Carta.
In many of their demands the barons and bishops who forced the Magna Carta on King John quite naturally acted in their own best interests. Careful provision was made for limiting royal taxes and assessments, for reforming laws and judicial procedures, and for suppressing the misuse and extension of forest law. In addition, the Magna Carta provided certain guarantees for the people as a whole. The document has a total of 63 sections. Although much of it deals with feudal rights and duties, it also includes provisions that protect the rights of the church, merchants, and townspeople. One of the sections protecting merchants reads, translated from the original Latin: “All merchants shall be able to go out of and come into England safely and securely and stay and travel throughout England for buying and selling free from all evil tolls, except in time of war and if they are of the land at war with us.”

AIDS

AIDS
AIDS was first conclusively identified in the United States in 1981, when 189 cases were reported to the Centers for Disease Control and Prevention. Within a decade the disease had spread to virtually all populated areas of the world. At the end of 2001, 40 million people worldwide were living with the AIDS virus. Roughly 70 percent of these lived in sub-Saharan Africa and 17 percent in South and Southeast Asia. Worldwide, almost 14,000 people are infected with HIV each day, with 95 percent of these new infections occurring in developing countries. HIV and AIDS are not limited by global economics, however—approximately 940,000 people in the United States and 560,000 people in Western Europe were living with HIV by the end of 2001; almost 5 percent of these infections were acquired that year. The region with the fastest rising rate of new HIV infections was Eastern Europe and Central Asia, where roughly 1 million people were positive for HIV by the end of 2001, a quarter of these newly infected that year.
The first AIDS patients in the Americas and Europe were almost exclusively male homosexuals. Later patients included those who used unsterilized intravenous needles to inject illicit drugs; hemophiliacs (persons with a blood-clotting disorder) and others who had received blood transfusions; females whose male sexual partners had AIDS; and the children of such couples. After 1989, heterosexual sex became the fastest growing means of transmission of the virus, with 80 percent of new adult cases worldwide originating from heterosexual sex. Approximately 44 percent of the people living with HIV/AIDS in 2001 were women.
Public awareness of the disease gradually increased as high-profile individuals died from the disease or revealed that they were infected with the AIDS virus. The fact that these public figures had diverse backgrounds and lifestyles helped negate the stereotypes that were associated with AIDS and demonstrated that anyone could be at risk for infection.
HIV: The AIDS Virus
The initial name given to the virus that causes AIDS was the human T-lymphotrophic virus type III (HTLV-III). In the late 1980s, scientists realized that there were several forms of the virus and renamed the original virus human immunodeficiency virus type 1 (HIV-1). Scientific evidence suggests that the virus originated in nonhuman primates, probably chimpanzees, in Africa.
The virus enters the bloodstream and destroys certain white blood cells called CD4+ cells, a type of T lymphocyte that plays a key role in the functioning of the immune system. The virus can also infect other types of cells in the body, including the immune-system cells known as macrophages. Unlike T lymphocytes, however, macrophages are not killed by the virus. Research has suggested that macrophages may carry HIV to the brain, leading to the syndrome of neurological disorders known as AIDS dementia complex (ADC) that is seen in some long-term patients.

UNITED NATION

UNITED NATION

The United Nations (UN) is an international association of independent states that was founded by the victorious nations of World War II to keep the peace their efforts had won. Its supreme goal was to end war, but by the end of the 20th century the organization had expanded its mandate to cover a varied agenda that included such issues as human rights, world poverty, public health, and environmental concerns. Membership was eventually extended to almost every country on Earth, growing from the initial 51 member nations in 1945 to 191 by 2002.
After WORLD WAR II it was expected that the great powers would work together to keep the peace. Instead, disagreements between the Soviet Union and the West beginning in the late 1940s created a state of international tension called the Cold War. The Soviet Union's goal was to spread the communist system of government throughout the world The Western nations, led by the United States, joined together to resist communist expansion. Both sides built up their weapons, which included nuclear arms. During this era the United Nations played a key role as peacemaker between East and West. After the Cold War ended in the early 1990s with the collapse of the Soviet Union, the United Nations continued to promote peace and cooperation throughout the many troubled areas of the world, adapting to circumstances that were not dreamed of by its founders.

Origin of the United Nations
In 1942 representatives of 26 countries, calling themselves the United Nations, signed a pledge in Washington, D.C., to defeat the Axis Powers—the alliance of Germany, Italy, and Japan—and to uphold the principles of the Atlantic Charter. In 1944 representatives of China, the United Kingdom, the Soviet Union, and the United States drew up plans for a world organization when they met at Dumbarton Oaks, a private mansion in Washington, D.C.
In February 1945, at a conference in the Crimean city of Yalta on the Black Sea, representatives of the United Kingdom, the Soviet Union, and the United States discussed procedures for the organization and called for a conference to draw up a charter. On April 25, 1945, the United Nations Conference on International Organization opened in San Francisco; Calif. Delegates of 50 nations discussed and modified the original Dumbarton Oaks proposals. On June 26 the United Nations Charter was completed, signed, and sent to the member nations for ratification. In the United States, the Senate voted 89 to 2 on July 28, 1945, to ratify the charter. By Oct. 24, 1945, the required number of nations had ratified the charter and the United Nations officially came into existence. October 24 has been celebrated as United Nations Day since 1948. Some countries set aside seven days—United Nations Week—for educational and social programs.


The United Nations Charter
The preamble of the United Nations Charter sets forth the aims of the organization. The charter itself states the basic principles and purposes, defines the membership, and establishes the six principal departments, which are also called organs.
The original members of the United Nations numbered 51. The charter provides, however, that “all other peace-loving states” can become members on the recommendation of the Security Council if approved by a two-thirds vote of the General Assembly. The Assembly, on recommendation of the Security Council, can expel a member that has persistently violated the principles of the charter.
Amendments to the charter require a vote of two thirds of all the members of the General Assembly. Following Assembly approval, the amendment must be ratified by two thirds of the member states, including all five permanent members of the Security Council.
In addition to sharing the risks of maintaining peace and security, the member states of the UN share in the financial burden of maintaining the organization. Each member nation contributes to the main budget and to the budget of each agency to which it belongs. The scale of contributions, based partly on ability to pay, is set by the General Assembly. Some states pay less than half of 1 percent of the budget. The largest contributors in the early 21st century were the United States, Japan, Germany, France, Italy, and the United Kingdom.

The Six Basic Organs
The duties with which the United Nations is charged are so vast that it was determined from the beginning to divide the organization into functional arms, or organs, that would address specific areas of peacekeeping and human rights.

The General Assembly
The largest of the six basic organs, the General Assembly is the great deliberative body of the United Nations. It is linked with all the other organs and it elects their membership. It may discuss any subject within the scope of the charter, except those disputes that are being dealt with by the Security Council. After voting, it may forward its recommendations to other organs or to member governments.
All member states are represented in the Assembly. Each state may have up to five representatives but only one vote. Decisions on important questions (listed in the charter) require a two-thirds majority of members present and voting. Other questions are decided by a simple majority of those voting.
The Assembly meets in regular annual sessions but may in some instances call a special session. A president is elected to oversee each session.

The Security Council
Maintaining world peace and security is the responsibility of the Security Council. Every member of the United Nations is pledged to accept and carry out the Council's decisions. The Council is set up to function continuously; thus a representative of each of its members must be present at all times at UN headquarters. The Council is headed by a president, chosen from among the Council members. This presidency changes monthly.
The Security Council has 15 members. Five nations, known collectively as the Big Five—China, France, Russia, the United Kingdom, and the United States—have permanent seats. (Russia's seat was held by the Soviet Union until that country's break-up in 1991.) Of the other 10 seats, five are elected each year by the General Assembly for two-year terms; five retire each year. Each member has one vote. On all routine (procedural) matters, approval requires nine “yes” votes. On all other matters, the nine “yes” votes must include the votes of all five permanent members. Thus, each of the Big Five has a veto power. Any one of them can block even the discussion of an action of which it disapproves. A party to a dispute, however, must abstain from voting.
Any state, even if it is not a member of the United Nations, may bring a dispute to which it is a party to the notice of the Security Council. The first response of the Council is always to search for a peaceful solution to the conflict. If the Council finds there is a real threat to peace, or an actual act of aggression, it may call upon the members of the United Nations to cut communications with the countries concerned or break off trade relations. If these methods prove inadequate, the charter states that the Council may take military action against the offending nation by air, sea, and land forces of the United Nations.
Every member of the United Nations is pledged by Article 43 to supply the Council with armed forces when needed. These forces are directed by a Military Staff Committee, consisting of the chiefs of staff (or their representatives) of the five permanent members.

The International Court of Justice
The International Court of Justice, sometimes also called the World court, is the supreme court of the United Nations. Its permanent seat is in The Netherlands at The Hague. The court consists of 15 judges, no two of whom can be from one nation, elected by the General Assembly and the Security Council. The judges serve for nine years and are eligible for reelection. Nine judges make a quorum and questions are decided by a majority vote.
Any states—even nonmembers—may bring disputes to the court for judgment. Both parties must first agree to allow the court to try the case. Should one of them fail to accept the judgment of the court, the other may appeal to the Security Council for enforcement. The court serves also as the legal adviser to the General Assembly, Security Council, and other United Nations organs.

The Economic and Social Council
The constructive tasks of peace—achieving higher standards of living, improving health and education, and promoting respect for human rights and freedoms throughout the world—are the responsibility of the Economic and Social Council. It works under the authority of the General Assembly and reports to the Assembly. The Council has 54 members, each of whom is elected to a three-year term. The Economic and Social Council is assisted by its own commissions and by independent specialized agencies.

The Secretariat
The UN Secretariat carries on the day-to-day business of the United Nations and assists all the other organs. At its head is the secretary-general, the chief administrative officer and spokesperson of the United Nations. The secretary-general embodies the ideals of the United Nations, drawing upon his or her personal integrity to prevent international disputes from escalating and helping to facilitate the work of the organization as needed. The secretary-general is appointed by the General Assembly upon recommendation of the Security Council. For many years the secretary-general's staff included thousands of workers from many countries. Efforts were begun in 1997 to trim the size of the department to control administrative costs. Because the secretary-general's responsibilities had expanded with the increased number of new UN programs, the post of deputy secretary-general was created in 1998.

The Trusteeship Council
The original responsibility of the Trusteeship Council was to protect the interests of people who lived in trust territories and to lead them toward self-government. Under the trusteeship system, colonial territories taken from countries defeated in war were administered by a trust country under international supervision until their future status was determined. The Council received reports from the administering authorities, examined petitions from trust territories, and sent out visiting missions. It consisted of states administering trust territories, permanent members of the Security Council that did not administer trust territories, and other UN members elected by the General Assembly.
The Trusteeship Council met once each year until Palau, the last trust territory, became independent in 1994. The Council then terminated its operations. No longer required to meet annually, the Trusteeship Council may meet on the decision of its president or on a request by a majority of its members, by the General Assembly, or by the Security Council. Since 1994 new roles for the Council have been proposed, including serving as a forum for minority and indigenous peoples.

Land and Natural Resources
Much of India's area of almost 1.3 million square miles (3.3 million square kilometers—including the parts of Kashmir occupied by Pakistan or China) is a peninsula jutting into the Indian Ocean between the Arabian Sea on the west and the Bay of Bengal on the east. There are three distinct physiographic regions. In the north the high peaks of the Himalayas lie partly in India but mostly just beyond its borders in Nepal, Bhutan, and Tibet. South of the mountains, the low-lying Indo-Gangetic Plain, shared with Pakistan and Bangladesh, extends more than 1,500 miles (2,400 kilometers) from the Arabian Sea to the Bay of Bengal. Finally, the peninsular tableland, largely the Deccan, together with its adjacent coastal plains, makes up more than half of the nation's area.

The Himalayas
The northern mountain wall consists of three parallel ranges. The highest of these ranges is the Greater Himalayas, which include several peaks that rise above 25,000 feet (7,600 meters). Even the passes through these mountains are farther above sea level than the highest summits of the Alps. India has the world's largest area under snow and glaciers outside the polar regions.
Lower mountain ranges branch off from both ends of the Himalayan system, running along the border with Myanmar toward the Bay of Bengal in the east and—mainly through Pakistan—toward the Arabian Sea in the west. Thus, the low-lying country to the south is relatively isolated from the rest of Asia. This accounts for its recognition as a subcontinent.

The Indo-Gangetic Plain
The Indo-Gangetic Plain, with an area of about 270,000 square miles (700,000 square kilometers), varies in width by several hundred miles. It is the world's most extensive tract of uninterrupted alluvium. These deep, river-deposited sediments give rise to fertile soils. In addition, they are rich in groundwater for well irrigation. The flat terrain also makes the area ideal for canal irrigation.
The greater part of the Indo-Gangetic Plain is drained by the Ganges River, which rises in the southern Himalayas and flows in a generally south to southeast direction to the Bay of Bengal. Its principal tributary, the Yamuna, or Jumna, flows past New Delhi, the capital of India, to join the Ganges near Allahabad. North of Goalundo Ghat in Bangladesh, the Ganges is joined by the Brahmaputra). The Indus and its tributaries drain the western and southwestern parts of the plain. The northern part of this area, now divided between India and Pakistan, is traditionally known as the Punjab, or Land of the Five Rivers, for the five major tributaries of the Indus—the Jhelum, Chenab, Ravi, Sutlej, and Beas).

INDIA
About one sixth of all the human beings on Earth live in India, the world's most populous democracy. Its borders encompass a vast variety of peoples, practicing most of the world's major religions, speaking scores of different languages, and divided into thousands of socially exclusive castes. A civilized, urban society has existed in India for well over 4,000 years, and there have been periods when its culture was as brilliant and creative as any in history. The country is also known by its ancient Hindi name, Bharat.
India's leaders have played a prominent role in world affairs since the country became independent in 1947. Nevertheless, the standard of living of most of its citizens is low. The huge population strains the nation's limited resources. Fertile, cultivable land is scarce, yet about two thirds of the people depend directly on agriculture for their livelihood. Many millions of Indians are inadequately nourished, poorly housed, and lacking in basic educational, medical, and sanitary services.
Although the modern nation of India encompasses the greater part of South Asia, it is smaller than the Indian Empire formerly ruled by Britan. Burma, a mainly Buddhist country lying to the east, was administratively detached from India in 1937. Ten years later, when Britain granted independence to the peoples of the Indian subcontinent, two regions with Muslim majorities—a large one in the northwest (West Pakistan) and a smaller one in the northeast (East Pakistan)—were partitioned from the predominantly Hindu areas and became the separate nation of Pakisthan. East Pakistan broke away from Pakistan in 1971 to form the independent nation of Bangladesh. Also bordering India on its long northern frontier are the People's Republic of China and the relatively small kingdoms of Nepal and Bhutan. The island republic of Sri Lanka lies just off India's southern tip. India's capital is New Delhi

SOFT DRINKS
In the manufacture of soft drinks, special attention must be paid to the purity and uniformity of ingredients. These ingredients include water, carbon dioxide, sugar or sugar substitutes, acids, flavoring, and sometimes coloring.
Water is usually taken from pure municipal sources. Nevertheless, because the amount of impurities in the municipal supply may vary from time to time, it generally undergoes further processing to ensure uniformity of the finished product. In some bottling plants the water-treatment equipment may consist simply of a sand filter to remove minute solid particles and an activated-carbon purifier to remove color, chlorine, and any other tastes or odors that may be present. In most plants, however, water is treated by a process known as super chlorination and coagulation. In this process the water is exposed to a high concentration of chlorine and to a flocculants that removes tiny organisms. The water is then passed through a sand filter and activated-carbon purifier.
Natural flavors are derived from fruits, nuts, berries, roots, herbs, and other plant sources. Flavoring syrup is made from sugar that is delivered to the soft-drink manufacturer either in granulated form or as a 67-percent or 76-percent solution known as liquid sugar. Sugars commonly known as corn sugars can also be used as substitutes for cane sugar. The sugar is dissolved or diluted with processed water, then combined with flavoring substances. Edible acids, principally citric acid, are added to give the mixture tartness. Natural or artificial coloring may also be added, and sometimes preservatives are used to protect the beverage from spoilage. Large quantities of synthetic sweeteners are used in the production of low-calorie beverages.
Special Kinds of Soft Drinks
Noncarbonated soft drinks are produced with much the same ingredients and techniques as are carbonated soft drinks. However, because they are not protected from spoilage by carbonation, they are usually pasteurized. This may be done in bulk or by continuous flash pasteurization either prior to filling or in the bottle.
Powdered soft drinks are made by blending flavoring material with such ingredients as dry acids, gums, and artificial color. If the sweetener has been included, the consumer needs only to add water to make the drink.

Silver
Soft, lustrous, white silver was one of the first metals known to humans. Together with gold, iridium, palladium, and platinum, it is one of the group called precious metals. Silver ornaments and decorations have been found in royal tombs dating back as far as 4000 BC. The silver mines worked by the Carthaginians in Spain were well known; Roman envy of this wealth helped bring on the Punic Wars. Probably the most famous silver deposit in the New World was the Comstock Lode, discovered near Virginia City, Nev., in 1859. It yielded over 225 million dollars in silver during its productive years.
Silver is somewhat harder than gold and is second only to gold in malleability and ductility. It can be beaten into silver leaf 1/100,000 of an inch (0.000025 centimeter) in thickness. One ounce (28 grams) of silver can be drawn into a fine wire about 30 miles (48 kilometers) long. As a conductor of heat and electricity, silver has no equal.
Unlike gold, silver is present in many naturally occurring minerals. Some silver is obtained in native form or from such ores as argentite (silver sulfide) or cerargyrite (silver chloride). Most domestic silver, however, is recovered as a by-product of smelting lead, copper, or zinc ores and from gold deposits. Pure silver is produced from the crude silver by-product either by electrolysis or by a chemical method
Silver is processed in many forms—ingots, sheets, wire, bullion, tubing, castings, and powder. Historically, a major use of silver has been monetary, in the form of reserves of silver bullion and of coins. By the 1960s, however, the demand for silver for use in industry exceeded the total annual world production.
Because silver does not react readily with organic acids and bases, it is used for lining vats, tanks, and other containers in the chemical and food industries. Because of the metal's high electrical conductivity, it is used for making printed electrical circuits and as a coating for electronic conductors, and it is alloyed with such elements as copper and gold for use in electrical contacts. In the photography industry, silver compounded with bromine or chlorine forms light-sensitive coatings that register images on films.
Silver acetate serves as an industrial oxidizing agent and laboratory reagent. Silver nitrate is used in silver plating, hair dyeing, and manufacturing ink, glass, and mirrors, and as a strong antiseptic. Silver oxide, a dark-brown powder, is used in medicines, in coloring glass, and in purifying drinking water. Silver iodide, a pale-yellow powder, is used chiefly in medicines, in photography, and in cloud seeding to produce rain artificially during drought conditions.
The use of silver for sterling and plated silverware, ornaments, jewelry, and similar products has continued to be significant. Alloys of silver with copper are harder, tougher, and more fusible than pure silver and are used for jewelry and coinage. The proportion of silver in these alloys is stated in terms of fineness, which means parts of silver per thousand parts of the alloy. Sterling silver contains 92.5 percent of silver and 7.5 percent of another metal, usually copper—that is, it has a fineness of 925. Jewelry silver is an alloy containing 80 percent silver and 20 percent copper (800 fine). Gold dental alloys contain about 75 percent gold and 10 percent silver. The yellow gold that is used in jewelry is composed of 53 percent gold, 25 percent silver, and 22 percent copper.
Historically, silver has been a substance that could be used for money, leading to its use as the standard for the monetary systems of ancient Greece and the Roman Empire. Silver continued to be the standard for most currencies until the 19th century, when most countries changed to a gold standard. Expanding industrial use of silver led to the elimination of silver in United States coinage in the 1960s. The price per ounce of silver rose so high that it would have been advantageous to melt down the coins for their silver content. The United States Department of the Treasury became a major supplier of silver to industrial users. The Treasury reduced the silver content of a half-dollar and introduced silverless dimes and quarters in 1965 to help maintain the supply of circulating coins. Finally, in 1967, the Treasury withdrew all silver coins from circulation.

Magnetic Fields
A magnet can attract or repel another magnet or a piece of soft iron without touching it. Magnetic forces are exerted even when empty space, air, or any nonmagnetic material such as cardboard separates the two. Furthermore, two magnets can exert a force on each other even when they are placed at an angle to each other. Scientists describe the space around a magnet as occupied by a magnetic field. They can “map” the field by observing the direction of the magnetic force at many points around the magnet.
For example, a small compass may be placed in different positions near a long bar magnet. Since the compass is free to swing around, it will point in the direction of the magnetic field at each position. By observing the way the compass points, the direction of the magnetic field at any position can be determined.
The compass is moved in short steps, always in the direction in which it points. After each move, the position of the compass is marked. If the marks are connected by lines, they are seen to start at one pole and move around to the other pole. These lines are called lines of force, or lines of flux, of the magnetic field. By convention, the magnitude of the magnetic field is described as positive when it goes from north to south, negative when it goes from south to north. The lines of force exist inside the magnet as well: they go from one pole to the other. One may also sprinkle tiny iron filings on a piece of stiff paper covering a flat bar magnet. If the paper is gently tapped while the iron filings are sprinkled, the filings jump around and arrange themselves along the lines of the magnetic field. Where the lines are close to one another, the field is strong; where the lines are far apart, the field is weak. The lines and the filings are densest at the poles of the magnet, where the magnetic field is strongest.
The shape of a magnetic field can be changed by changing the shape of a magnet. If a long bar magnet is bent into a horseshoe shape, the magnetic poles are brought closer together. Most of the magnetic field lines lie between the two tips of the horseshoe. Since the field is strongest where the lines are densest, this shape produces a highly concentrated field between the two tips of the horseshoe. Magnets can be made in other shapes to produce other magnetic field patterns.

Forces
Scientists consider both forces and velocities as vectors. Vectors are shown by arrows: they represent quantities that have both a specific magnitude—size or strength—and direction. Velocity, for example, has both magnitude and direction. Although the words speed and velocity are used interchangeably, speed is properly only the magnitude of the velocity vector. A complete description of an object's velocity requires both a knowledge of the object's speed and the direction in which it is traveling. For example, a stone whirled in a circle at the end of a string has a changing velocity even if it moves at a fixed number of revolutions per minute. The stone's speed is constant, but its direction of travel, and therefore its velocity, changes continuously. The force on the stone that causes the change in velocity is another vector, called a centripetal force. Its magnitude is the tension in the string, and its direction is radially inward toward the center of the circle described by the spinning stone.

Two forces applied simultaneously to the same point have the same effect as a single equivalent force. The magnitude and direction of this resultant force can be found by drawing the two original force vectors head to tail and then drawing a new vector—the resultant force vector—from the tail of the first vector to the head of the second. Similarly, vectors can also be added by the use of parallelograms (see diagram).
The same forces can have different effects depending on how they are applied and on the specific body to which they are applied. For example, if applied in a certain way, a force may cause a body to spin, or rotate. The tendency of a force to rotate the body to which it is applied is called torque, or moment of the force. Torque is also a vector. The magnitude of the torque can be calculated by multiplying the perpendicular distance between the line of the force and the axis of rotation.
The force that resists the motion of a body along a path or the torque that opposes rotation is called friction. Both frictional forces and frictional torques are passive and do not exist alone. They appear only when other forces are applied or if a body is already in motion. Friction may be undesirable, as in the case of air resistance that slows down an airplane, or it may be useful, as it is in the case of car brakes, which slow down a car by means of friction

Alicia Stott
(June 8, 1860 - December 17, 1940) mathematician
Alicia Boole Stott's father was the mathematician George Boole (for whom Boolean logic is named). He was teaching in Ireland when Alicia was born there, in 1860, and he died four years later. Alicia lived with her grandmother in England and her great-uncle in Cork for the next ten years before she rejoined her mother and sisters in London.
In her teens, Alicia Stott became interested in four-dimensional hypercubes, or tesseracts. She became secretary to John Falk, an associate of her brother-in-law, Howard Hinton, who had introduced her to tesseracts. Alicia Stott continued building models of wood to represent four-dimensional convex solids, which she named polytopes, and published an article on three-dimenstional sections of hypersolids in 1900.
She married Walter Stott, an actuary. They had two children, and Alicia Stott settled into the role of homemaker until her husband noted that her mathematical interests might also be of interest to the mathematician Pieter Hendrik Schoute at the University of Groningen. After the Stotts wrote to Schoute, and Schoute saw photographs of some models that Alicia Stott had built, Schoute moved to England to work with her.
Alicia Stott worked on deriving Archimedean solids from Platonic solids. With Schoute's encouragement, she published papers on her own and that the two of them developed together.
In 1914, Schoute's colleagues at Groningen invited Alicia Stott to a celebration, planning to award to her an honorary degree. But when Schoute died before the ceremony could be held, Alicia Stott returned to the her middle class life at home.
In 1930, Alicia Stott began collaborating with H. S. M. Coxeter on the geometry of kaleidoscopes. She also constructed cardboard models of the "snub 24-cell."
She died in 1940.

PACKET FOOD
A limited selection of food that is prepared in advance and within minutes of being ordered is known as fast food, and fast-food restaurants are popular eating places in most populated places in the United States. For many decades there have been hot dog, hamburger, and other snack stands that offer almost-instant meals. Modern fast-food establishments, however, differ from both the restaurant and such snack stands in that most of them belong to chains of franchise outlets. This enables them to offer a great number, yet still limited selection, of dishes at nominal prices and still make an adequate profit.
Because they are chains, the food they sell is virtually the same at every outlet, and they generally specialize in one kind of food such as hamburgers, pizza, chicken, or tacos. This specialization and standardization is maintained by the terms of the franchise agreement, which requires every outlet to offer the same type of service and to buy its inventory from approved wholesalers. Some chains, however, have begun to diversify. McDonald's, for example, has experimented with pizza, fried chicken, and submarine sandwiches, and many restaurants now serve breakfast.
Apart from immediate service and standardized products, fast-food establishments differ from other restaurants by selling food over a counter. There may be tables, and the food may be eaten on the premises, but customers are not seated and offered a menu. There are restaurant chains—such as Shoney's, Red Lobster, and Denny's—that provide quick service and standardized menus, but they operate more like regular restaurants in that they provide table service and offer a wider range of food and beverages. Dining in these establishments is generally a more leisurely experience than that offered by fast-food outlets, and they are also more expensive.
Most fast-food meals are high in fat and sodium and low in fiber and nutrients. Although consumers may choose chicken or fish entrees as lower-fat alternatives, fried patties and nuggets may derive more than 50 percent of their calories from fat, well over the 30 percent recommended by public health organizations. Some chains provide reduced-fat hamburgers, salads, low-fat milk, and juices.
Although some fast-food operations—White Castle hamburgers, for example—have been in business for several decades, the great growth in these establishments took place only after World War II. Two of the largest companies, McDonald's and Kentucky Fried Chicken, were founded in 1955. By the early 1990s there were more than 500 food franchising companies with a combined total of more than 70,000 retail outlets in the United States. Of these outlets about 48,000 are owned by franchisees, while 22,000 are owned by the companies and leased to operators. McDonald's owns all of its outlets; some companies sell their franchises; others, such as Kentucky Fried Chicken, both sell and lease.
While McDonald's and a few other food franchising companies remain independent corporations, most companies have been bought by larger firms. Burger King, for example, is owned by a British corporation, Grand Metropolitan PLC. Pizza Hut, Kentucky Fried Chicken, and Taco Bell are all owned by Pepsico, Inc.
American-style fast-food emporiums have appeared around the globe. Of the more than 4,000 foreign outlets, most are in the United Kingdom, Western Europe, Japan, Australia, and New Zealand. In the late 1980s American fast-food companies began establishing outlets in Communist nations. Pizza Hut opened a branch in the Soviet Union in 1990, and by 1991 the McDonald's in Moscow's Red Square, serving 27,000 customers per day, had become more popular with tourists than Lenin's tomb.
OLESTRA
Olestra, was developed by Procter & Gamble as a replacement for fat in foods. Although the components of olestra—sucrose (table sugar) and fatty acids—are naturally occurring substances, the product itself is synthetic. Despite its approval in 1996 by the United States Food and Drug Administration (FDA) for use in salted snack foods, olestra drew heavy criticism from consumer-advocate groups because of reports by consumers of gastrointestinal malaise following consumption of products that contained olestra. Further scrutiny by medical researchers revealed that olestra interferes with blood levels of many important fat-soluble substances including carotenoids, which have been associated with lowered risk of heart disease and some cancers.
Olestra was discovered in 1968 by two Procter & Gamble researchers who were studying fat digestion. Their investigations led to the identification of a fat-like substance that was not degraded and digested by the body. The substance was originally called sucrose polyester, because its components of sucrose and fatty acids were chemically bound by ester bonds. The chemical name of the substance was eventually changed to olestra, and the corporation began conducting studies to examine what, if any, changes occurred when the substance was used as a cooking oil. Although not the first fat replacer discovered, olestra was the first that did not break down when used at high temperatures, thus it could be used for frying.
During the 1970s, Procter & Gamble conducted numerous investigations to study the safety of, and uses for, olestra in foods. In 1987, they petitioned the FDA for approval to use olestra as a general fat substitute in snack products. At the same time, the Center for Science in the Public Interest (CSPI), a consumer-advocate group, publicly criticized the product, charging that the tests conducted by Procter & Gamble were inadequate, and that the product produced, among other things, severe gastrointestinal (GI) symptoms, including flatulence, fecal incontinence, diarrhea, and anal leakage. Furthermore, the studies had revealed that the product interfered with the absorption of important fat-soluble nutrients, such as vitamins A, D, E, and K, and many carotenoids. Procter & Gamble responded by modifying the structure of olestra, as well as supplementing it with vitamins. Although it was subsequently approved by the FDA in 1996, all products using olestra—which is marketed under the trade name Olean®—must contain a warning about the adverse effects of olestra. After its release in 1998 on the United States market as an ingredient in several popular snack foods it continued to cause GI illnesses in some people despite the modifications made by the manufacturers.
Chemically, a molecule of olestra consists of a molecule of sucrose esterified to up to eight fatty-acid residues. The large size of the molecule, as well as the large number of fatty-acids, prevents it from being metabolized by GI bacteria and enzymes. Because of its fatty nature, olestra has a strong affinity for many fat-soluble substances. Whereas natural fats are broken down and absorbed by the intestine, olestra is passed through, and along its route it absorbs many valuable nutrients such as cholesterols, vitamins, and phytochemicals such as carotenoids, lycopene, and lutein.

Chemistry
The most abundant of the fatty acids combined in fats and oils are called stearic, palmitic, and oleic. Compounds having only one acid are called stearin, palmitin, and olein. Beef tallow is rich in stearin and palmitin, which are solids at room temperature; olive oil is mostly olein, a liquid. Most vegetable fats and oils contain all three of these acids. Small quantities of various substances, including other fatty acids, give fats and oils their distinctive odors and flavors.
Fats and oils are unsaturated or saturated, depending on the way in which carbon atoms are bonded together in their molecular structure. An unsaturated oil can be made saturated by applying heat and pressure to the oil in an atmosphere of hydrogen. This process, called hydrogenation, is used to change vegetable oils to solid fats for making margarine and cooking fats.

ELECTRONS IN AN ATOM

ELECTRONS are one of the subatomic particle seen in an atom. It is rotating the nucleus through a path called Orbit. They are negatively charged particle. If an atom loss or gain electrons, they become an ION. Electronwas discovered by J.J.THOMSON

DISCOVERY OF ELECTRON:-

Electrons are discovered through an expirement called DISCHARGE TUBE EXPIREMENT.Discharge tube is a long glass tube of 50cm length. Two metal electrodes are sealed at the two end of the tube. The inner surface is coated with the Zinc sulphide (ZnS).There is a side tube connected with the vacuum pump.The pressure is reduced to 1/10000 atm. And an eletric charge of 10000volt is applied accross the tube. ZnS infront of the tube glows .because of some rays coming from negatively charged electrode(cathode).this is named as cathode rays.