Education

Cassava, also known as MANIOC, MANDIOC, and YUCA (Manihot esculenta), a member of the flowering-plant family Euphorbiaceae from the American tropics. It is cultivated throughout the tropical world for its tuberous roots, from which cassava flour, breads tapioca, a laundry starch, and even an alcoholic beverage are derived. Cassava probably was first cultivated by the Maya in Yucatan.

A cyanide-producing sugar derivative occurs in varying amounts in most varieties. Primitive peoples developed a complex refining system to remove the poison by grating, pressing, and heating the tubers.

An extremely variable species, cassava probably is a hybrid. It is a perennial with conspicuous, almost palmate (fan-shaped) leaves resembling those of the castor bean but more deeply parted into five to nine lobes.

The fleshy roots are reminiscent of dahlia tubers. Different varieties range from low herbs through much-branching, 90-centimetre- (3- foot-) tall shrubs to slender, unbranched 5- metre (16-foot) trees. Some are adapted to dry areas of alkaline soil and others to acid mud- banks along rivers.

All the approximately 150 species of the genus Manihot are sun-loving natives of tropical America. Ceará rubber is produced from M. glaziovii, from northeast Brazil. Food items such as the gelatinous fufu of West Africa and the banii mush of Jamaica come from cassava. Additional cassava products include an alcoholic beverage made Indians in South America, the powdery casabe cakes of Yucatan, and tapioca, the only cassava product on northern markets. syntec communications

Coniferous forest, vegetation composed primarily of cone-bearing, needle-leaved or scale-leaved evergreen trees, found in regions of the world that have long winters and high annual precipitation. The northern Eurasian coniferous forest is called the taiga or the boreal forest. Both terms are used to describe the entire circumpolar coniferous forest with its many lakes, bogs, or muskegs, and rivers. Areas of coniferous-forest vegetation also cover mountains in many parts of the world. Pines, spruces, firs, and larches are the dominant trees in coniferous forests. They are similar in shape and height and often form a nearly uniform stand with a layer of low shrubs or herbs beneath. Mosses, liverworts, and lichens cover the forest floor.

The light-coloured, usually acidic soils of coniferous forests are called podsols and have a compacted humus layer, known as mor, which is characterized by the presence of many fungi. These soils are low in mineral content, organic material, and number of invertebrate animals such as earthworms.

Mosquitoes, ifies, and other insects are common inhabitants of the coniferous forest, but few cold-blooded vertebrates, such as snakes and frogs, are present because of the low temperatures. Bird life is well represented by woodpeckers, crossbills, warblers, kinglets, nuthatches, waxwings, grouse, and several hawks and owls, Prominent mammals include shrews, voles, squirrels, martens, moose, reindeer, and wolves,
Eurasian coniferous forest is dominated in the east by Siberian pine (Pinus sibirica), Siberian fir (Abies sibirica), and Siberian and Dahurian larches (Larix russica and L.

gmelini). Scots pine (Finus sylvestris) and Norway spruce (Picea abies) are the important species in western Europe.

North American coniferous forest is dominated throughout by white spruce (Picea glauca), black spruce (Picea mariana), and balsam fir (Abies balsamea), although lodgepole pine (Pinus contorta) and alpine fir (Abies lasiocarpa) are important species in the western section.

A distinct subtype of the North American coniferous forest is the moist temperate coniferous forest, or coast forest, which is found along the west coast of North America eastward to the Rocky Mountains. This subtype is sometimes called temperate rain forest, although this term is properly applied only to broad-leaved evergreen forests of the Southern Hemisphere. Warm temperatures, high humidity, and often misty conditions encourage the development of a mossy, moisture- loving plant layer under the giant trees of Sitka spruce (Picea sitchensis), western red cedar (Thuja plicata), western hemlock (Tsuga heterophylla), Douglas fir (Pseudotsuga menziesii), and coast redwood (Sequoia sempervirens).

Other subtypes of coniferous forest occur at various elevations in the Rocky Mountains of North America, in Central America, and in eastern Asia. They are known as subalpine and montane forests and are dominated by combinations of pine, spruce, and fir species. Daina Hersh

Sesame, also called BENNE, oldest herb known for its seeds, which are used as food and flavouring for foods, or the oil crushed from the seeds. The whole seed is used in Near Eastern confectionery, such as halvah, and to flavour various foods, particularly breads and baked goods. The aroma of sesame seed is faintly nutlike; the taste is agreeable, similar to toasted nuts. The chief constituent of sesame seed is its fixed oil, which usually amounts to about 44 to 60 percent. Noted for its stability, the oil resists oxidative rancidity. It is used as a salad or cooking oil, in shortening and margarine, and in the manufacture of soaps, pharmaceuticals, and lubricants. Sesame oil is used as an ingredient in cosmetics. The press cake remaining after the oil is expressed is a rich source of protein, especially methionine, calcium, phosphorus, and niacin; it is eaten by the poor and used as cattle feed.

Ancient in its origins, sesame probably originated in Asia or East Africa, then spread to most of the tropical, subtropical, and southern temperate areas of the world, Before the time of Moses, the Egyptians used the ground seed as grain flour.

The Chinese used it 5,000 years ago, and for centuries they have burned the oil to make soot for the finest Chinese ink blocks. The Romans ground sesame seeds with cumin to make a pasty spread for bread. Once it was thought to have mystical powers, and sesame still retains a magical quality as shown in the expression “open sesame,” from The Arabian Nights tale of “All Baba and The Forty Thieves.”

The plant, Sesamw’n mdi cam, is an erect annual of many types and varieties belonging to the family Pedaliaceae. It is cultivated in Central America, Brazil, Egypt, India, Thailand (where it is called tee!), and Texas. Depending on conditions, varieties grow from about 2 to 9 feet (½ to 21/2 metres) tall; some have branches, others do not. One to three flowers appear in the leaf axils. Hulled seeds are creamy or pearly white, about 0.1 inch (3 millimetres) long, and have a flattened pear shape. The seed capsules open when dry, allowing the seed to scatter. Considerable hand labour is needed in harvesting to prevent loss. In 1943 a nonscattering mutant was discovered, making mechanized production of this crop a possibility. Andrew Collier

Russell Chamberlin's book, the Tower Of London, is a historical view on the history of England through the eyes of it's architecture. Chamberlin's analysis summarizes the development of the Towers, to the present day as a monument. This historic fortress was built on the remains of Roman fortifications. It was built in the late 12th century under the reign of King William II (1065-1087). Although its exterior walls were restored in the 18th century, the interior still has much of its original Norman character. Later buildings surrounding the original keep include a barracks and a chapel built in the 14th century and restored in the 16th century. The inner fortifications, called the Ballium Wall, have 12 towers: the Bloody Tower, the Wakefield Tower, the Bell Tower, the Lanthorn Tower, the Salt Tower , the Broad Arrow Tower, the Constable Tower, the Martin Tower, the Brick Tower, the Bowyer Tower, the Flint Tower, the Devereux Tower, and the Beauchamp Tower.

The tower was used as a royal palace as well as for a prison until Elizabethan times. Use of the tower as a prison was discontinued in the 19th century. Executions were held either in the central keep or outside the tower on Tower Hill. It is now largely a showplace and museum. It holds the crown jewels of England and is one of the country's greatest tourist attractions. A popular feature is the Yeomen of the Guard, known as Beefeaters, who still wear colorful uniforms of the Tudor period.

This book contains some wonderful pictures but is not the comprehensive history I had expected. In fact, it is primarily an extended guidebook. It details all the building works that have ever taken place at the Tower - including demolitions and re-building - and not enough about the historic events played out within its forbidding walls.

Source: Russell Chamberlin, The Tower of London: an Illustrated History (Webb & Bower, 1989.) Eric Wright

In the New World, there were ancient people who, like the Chaldeans and the Chinese, used writing to record eclipses and from these records detected a rhythm by which they could predict them or at least warn of their likelihood. Those people were the Maya, and we know of their achievement through one of their books—one of only four that survived the Spanish conquest and its zealous destruction of the religious beliefs of the native peoples.

All that we know of Maya accomplishments in recognizing the patterns of eclipses comes from the Dresden Codex, written in hieroglyphs and pictures in color paints on processed tree bark with pages that open and shut in accordion folds. The book dates from the eleventh century A.D. and is probably a copy of an older work.
We can only wonder what was lost when the conquering Spaniards destroyed by the thousands the books of the Maya and other Mesoamerican peoples. What remains is impressive enough. The Maya realized that discernible eclipses occur at intervals of five or six lunar months. Five or six full moons after a lunar eclipse, there was the possibility of another lunar eclipse. Five or six new moons after a solar eclipse, another solar eclipse was possible.

The Maya had discovered in practical, observable terms the approximate length of the eclipse year, 346.62 days, and the eclipse half year of 173.31 days. The interval for one complete set of lunar phases is 29.53 days. Six lunations amount to approximately 177.18 days, close enough to the eclipse half year (173.31 days) so that there is the "danger" of an eclipse at every sixth new or full moon, but not a certainty. After another six lunar months, the passing days have amounted to 354.36, nearly 8 days too long to coincide with the Sun's passage by the Moon's node.

An eclipse is less likely. As the error mounts, the need increases to substitute a five-lunar-month cycle into the prediction system rather than the standard six-lunar-month count.

Some great genius must have noticed after recording a sizable number of eclipses that major eclipses were occurring only at intervals of 177 days (6 lunar months) or 148 days (5 lunar months). Using the date of an observed solar or lunar eclipse, it would then have been possible to predict the likelihood of another eclipse, even though in some cases an eclipse would not occur and in others it would not be visible from Mesoamerica.

In the Dresden Codex there are eight pages with a variety of pictures representing an eclipse. Each depiction is different, but most show the glyph for the Sun against a background half white and half black. In two of the pictures, the Sun and background are being swallowed by a serpent. Leading up to each picture is a sequence of numbers: a series of 177s ending with a 148. Each sequence adds up to the number of days in well-known three- to five-year eclipse cycles. At the end of each burst of numbers stands the giant, haunting symbol of an eclipse.

From the Maya, we have the numbers that demonstrate one of the greatest of their many discoveries about the rhythms of the sky, but we have no account of the emotion the astronomer-priests or the common folk felt when they observed an eclipse. Perhaps the closest we can come is a passage in the Florentine Codex of the Aztecs, who inherited and used the Mesoamerican calendar but apparently knew little of the astronomy discovered by the Maya a thousand years and more before. Alan Benson