Science & Philosophy: Revaluation of values: to Sarin Gas - History And Global Production Of Sarin

Science Encyclopedia

Revolution - Classical And Christian Conceptions, The Seventeenth Century, Inventing Revolution: American And French Revolutions, The Revolutionary Idea In The Modern World

It is tempting to give a definition of revolution at the outset of an account such as this. This is a temptation to be resisted. The great sociologist Max Weber (1864–1920) was right to say that "definition can be attempted, if at all, only at the conclusion of the study." Another great thinker, Friedrich Nietzsche (1844–1900), declared that "only that which has …

2 minute read

Reye's Syndrome

Reye's syndrome is a serious medical condition associated with viral infection and aspirin intake. It usually strikes children under age 18, most commonly those between the ages of five and 12. Symptoms of Reye's syndrome develop after the patient appears to have recovered from the initial viral infection. Symptoms include fatigue, irritability, and severe vomiting. Eventually, neuro…

2 minute read

Rhesus Monkeys

Rhesus monkeys (Macaca mulatta) are macaques belonging to the primate family Cercopithecidae. These medium-sized monkeys are colored from golden-brown to gray-brown. Rhesus monkeys spend most their time on the ground, although they take to trees readily, and have great agility in climbing and leaping. Typical body weights range from 11 to 26.5 lb (5-12 kg) for adult male rhesus monkeys, and from 9…

5 minute read

Rhetoric - Universality, The Art Of Persuasion, Description, History, General Assessment, Bibliography

Rhetoric governs the effective use of verbal and nonverbal communication designed to influence an audience. Understood in its broadest sense, it is practiced more or less deliberately in all societies. Even the animal world seems to apply some of its principles. But in its original and historical form, rhetoric is associated with the use of human discourse to persuade and can be defined as the art…

1 minute read

Rheumatic Fever - Cause Of Rheumatic Fever, Major Signs Of Rheumatic Fever, Treatment And Prevention - Signs and symptoms of rheumatic fever, Minor signs of rheumatic fever

Rheumatic fever is a rare complication that occurs after an infection with Streptococcus pyogenes bacteria. The most common type of S. pyogenes infection is "strep throat," in which the tissues that line the pharynx become infected with the bacteria. Rheumatic fever does not occur if the initial strep infection is treated with antibiotics. Major symptoms of rheumatic fever include in…

1 minute read

Rhinoceros

Rhinos are heavily built, thick-skinned, herbivorous mammals with one or two horns, and three toes on each foot. The family Rhinocerotidae includes five species found in Asia or Africa, all of which are threatened by extinction. The two-ton, one-horned Great Indian rhinoceroses (Rhinoceros unicornis) is a shy and inoffensive animal that seldom acts aggressively. This rhino was once abundant in Pak…

3 minute read

Rhizome

A rhizome is a root-like, underground stem, growing horizontally on or just under the surface of the ground, and capable of producing shoots and roots from its nodes. Rhizomes are most commonly produced by perennial, herbaceous species of plants, that die back to the ground at the end of the growing season, and must grow a new shoot at the beginning of the next season. Rhizomes are capable of stor…

1 minute read

Rhubarb

Rhubarbs are several species of large-leaved, perennial, herbaceous plants in the buckwheat family (Polygonaceae). Rhubarbs originated in eastern Asia and were not cultivated in Europe until the nineteenth century. Rhubarbs have been used as medicinal plants, as food, and as garden ornamentals. The initial uses of rhubarb were medicinal, for which both the medicinal rhubarb (Rheum officinale) and,…

1 minute read

Ribbon Worms

Ribbon worms, also called bootlace worms or proboscis worms, derive their common names from their threadlike or ribbonlike form, and from the characteristic reversible proboscis which they use in prey capture or in burrowing. The phylum Nemertea (or Rhynchocoela) includes approximately 900 described species of these worms. Most of them are marine, living in sand or mud, or under shells and rocks; …

1 minute read

Ribonuclease

Ribonuclease (RNase) is the name of a group of enzymes that change ribonucleic acid (RNA) by digesting (cutting) phosphorus-oxygen bonds. The RNases are the subject of wide investigation in the laboratory, though scientists are still learning the many ways they work in living cells. The best-studied RNase is from the pancreas of cattle. Its main portion, called ribonuclease A, was the first enzym…

3 minute read

Ribonucleic Acid (RNA) - The Discovery Of Rna, The Role Of Rna In Gene Expression

Ribonucleic acid (RNA), like deoxyribonucleic acid (DNA), is composed of nucleic acids that are found in the nucleus of plants and animals. Nucleic acids consist of high–molecular–weight macromolecules, which are made up of hundreds or thousands of smaller single unit molecules called nucleotides, all bound together. These molecules are the storehouse and delivery system of genetic t…

1 minute read

Ribosomes

Ribosomes are protein manufacturers within cells. Huge molecules of DNA, or deoxyribonucleic acid, coiled within the chromosomes of every living organism use a universal language called the genetic code. Employed by all cells in the same fashion, the information encoded in DNA acts as a set of instructions for the synthesis of vital protein molecules. Cells assemble thousands of different kinds of…

2 minute read

Rice

Rice is a species of grass (family Poaceae) that is an extremely important cereal crop. Two species of rice are grown as food: Oryza sativa and O. glaberrima. The natural range of both these rice species is tropical Asia, although rice can also be cultivated in warm-temperate regions. Of the two species, O. sativa is much more widely grown. In addition, there are seven major varieties of O. sativa…

1 minute read

RNA Function

RNA, which is made up of nucleic acids, has a variety of functions in a cell and is found in many organisms including plants, animals, viruses, and bacteria. Ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) differ functionally. DNA primarily serves as the storage material for genetic information. RNA can function as a carrier of genetic information, a catalyst of biochemical reactions, an ad…

5 minute read

RNA Splicing

RNA splicing is the process in which introns, or intervening sequences within a gene, are removed from ribonucleic acid (RNA) transcribed from deoxyribonucleic acid (DNA), prior to translation of RNA into protein. Prior to the early 1970s, the structure of genes had been elucidated and it was understood that genes were located with linear DNA sequences. The central dogma of molecular biology had b…

3 minute read

Robins - Status of North American robins

Robins are songbirds in the family Musicicapidae, in the thrush subfamily, Turdinae, which contains more than 300 species, including various thrushes, chats, solitaires, redstarts, nightingale, wheatear, and others. The members of this family, known as robins, tend to have dark backs and reddish breasts. Except for this superficial resemblance, these robins are not particularly closely related, ot…

4 minute read

Rockets and Missiles - History, Scientific Basis Of Rocketry, Rocket Propulsion, Solid Fuel Rockets, Specific Impulse, Multistage Rockets

The term rocket refers both to a non-air-breathing jet engine and to any vehicle it propels. Rocket fuels may be either solid or liquid. In the former case, the rocket is commonly known as a rocket engine, while in the latter case, it is usually called a rocket motor. A missile is an unmanned vehicle propelled through space, usually carrying some type of explosive intended to do harm to an enemy. …

1 minute read

Rocks - The Rock Cycle, Current Research - Types of rocks

Geologists define rocks as aggregates of minerals. Minerals are naturally occurring, inorganic substances with specific chemical compositions and structures. A rock can consist of many crystals of one mineral, or combinations of many minerals. Several exceptions, such as coal and obsidian, are not composed of minerals but are considered to be rocks. Common uses for rocks include building materials…

9 minute read

Rodents

A rodent is any mammal that belongs to the order Rodentia, which includes most mammals equipped with continuously growing incisor teeth that are remarkably efficient for gnawing on tough plant matter. The name rodent comes from the Latin word rodere meaning "to gnaw." Rodents live in virtually every habitat, often in close association with humans. This close association between roden…

4 minute read

Rollers

Rollers are 16 species of terrestrial birds in the family Coraciidae. Rollers occur in Africa, Eurasia, and Australia. Most species are tropical, but some occur in temperate climates. Rollers are stout-bodied birds, ranging in body length from 9.5 to 13 in (24 to 33 cm). Most species have rounded wings, and a square or forked tail, although a few have elongated, decorative tail feathers. Rollers h…

1 minute read

Romanticism in Literature and Politics - The First Generation In Britain And Germany, The Second Generation In Britain And Germany, French Romanticism

Romanticism is perhaps the richest and certainly the most vexed of the "isms." At the most general level, the term denotes a set of common tendencies in European art and thought from about 1797 to 1848. Ultimately those tendencies influenced the arts, especially literature, in virtually every country from Spain to Russia, but their acknowledged origins and centers were Britain, Franc…

9 minute read

Root System - Types Of Roots, Importance Of Roots

In most plants, the root system is a below-ground structure that serves primarily to anchor the plant in the soil and take up water and minerals. Roots may be less familiar than the more visible flowers, stems, and leaves, but they are no less important to the plant. Roots have four regions: a root cap; a zone of division; a zone of elongation; and a zone of maturation. The root cap is a cup-shape…

3 minute read

Rose Family (Rosaceae)

The rose family (Rosaceae), in the order Rosales, is a large plant family containing more than 100 genera and 2,000 species of trees, shrubs, and herbs. This family is represented on all continents except Antarctica, but the majority of species are found in Europe, Asia, and North America. Fossil evidence from Colorado, reliably identified as belonging to the genus Rosa, suggests that this family …

15 minute read

Rotation

A rotation is one of three rigid motions that move a figure in a plane without changing its size or shape. As its name implies, a rotation moves a figure by rotating it around a center somewhere on a plane. This center can be somewhere inside or on the figure, or outside the figure completely. The two other rigid motions are reflections and translations. Figure 1 illustrates a rotation of 30 …

4 minute read

Roundworms

With more than 10,000 species described, roundworms (phylum Nematoda) are among the most numerous and widespread animals. They occur in all habitats, including freshwater, marine, and terrestrial ecosystems, from the tropics to the polar regions. They often occur in staggering numbers: 10.8 sq ft (1 sq m) of mud has been found to contain more than four million nematodes. Because of their distribut…

2 minute read

Rumination

Rumination is a specialized digestion process found in most hoofed mammals with an even number of toes-such as cattle, sheep, goats, deer, antelope, camels, buffalo, giraffes, and chevrotains. All of these plant-eating animals lack the enzyme cellulase, which is capable of breaking down the tough cellulose in plant cell walls. The stomach of these grazing herbivores consists of four chambersȁ…

2 minute read

Rusts and Smuts

Rusts and smuts are fungi belonging to the orders Urediniales (rusts) and Ustilaginales (smuts) which are basidiomycete fungi. The rusts have complicated life cycles which involve the infection of two different plant species. The most well-known members of these groups are wheat rust (Puccinia graminis tritici) and corn smut (Ustilago myadis). Rust fungi attack plants such as ferns, gymnosperms, a…

4 minute read

Sacred Places - Stonehenge, The Great Pyramid, Delphi, The Temple Mount, The Church Of The Holy Sepulcher

Every civilization has its share of sacred places, that is, geographical locations, buildings, monuments, or environmental features, such as mountains, lakes, rocks, waterfalls, and so on, that are believed to be endowed with intense spiritual qualities. Indeed, such places are frequently thought to possess a variety of supernatural powers that can heal, rejuvenate, or otherwise affect the human b…

1 minute read

Sacred Texts - Asia - Later Additions To The Buddhist Canon, Regional Transmission, Bibliography

A more restrictive approach to questions of textual authority was presented in the Great Instruction Discourse (Mahapadesa-sutta, attributed to the Buddha but probably written after his death), in which he advises his followers to compare contested teachings with the corpus of discourses known to have been spoken by the Buddha. If a teaching or text accords with the oral instructions (Pali, sutta;…

2 minute read

Sacred Texts - Koran - The Koran And Previous Scriptures, History Of The Koranic Text, Themes And Styles, Controversy Over Whether The Koran Was Created

The traditional biography of Muhammad portrays the first encounter of this forty-year-old merchant with God's messenger Gabriel in a mountain cave as a terrifying experience. He is commanded to recite, yet does not know how or what to recite. Indeed, for Muslims the illiteracy, or at least lack of education, on the part of the Prophet is a guarantee that the revelations were not composed by…

1 minute read

Sage Philosophy - Historical Origins, Relation Between Sage Philosophy And Popular Myths, Conclusion, Bibliography

Sage philosophy is a body of knowledge attributed to wise men and women in communities and is regarded to be philosophically significant for both its content and its critical approach to the sustenance and growth of knowledge at the communal level. Although the term came into use rather recently in the course of African philosophers' appraisal of the nature and relation of philosophy to the…

1 minute read

Saiga Antelope

The saiga antelope (Saiga tatarica) is a relatively northern, Eurasian antelope in the family Bovidae. Historically, the range of the saiga antelope extended from Poland in the west, to the Caucasus Mountains of northwestern Turkey, Georgia, and Azerbaijan, the vicinity of the Caspian Sea in Kazakhstan, and as far east as Mongolia. However, mostly because of overhunting, this species now only occu…

2 minute read

Salmon - Atlantic Salmon (salmo Salar), Pacific Salmon (oncorhynchus Species), Water Pollution, Fishing, And Fish-farming

Salmon are various species of medium-sized, fusiform (a vertically compressed, torpedo shape) fish with small scales. Their fins are arranged like those of most freshwater fish. On the underside are two pectoral fins, a pair of pelvic fins, an anal fin, and a caudal (or tail) fin. On the back are a dorsal fin and a smaller adipose fin located in front of the tail. The mouth is wide and has numerou…

3 minute read

Salmonella - Causes And Symptoms, Treatment, Prevention - Diagnosis

Salmonella is the common name given to a type of food poisoning caused by the bacteria called Salmonella enteritidis (other types of illnesses are caused by other species of Salmonella bacteria, including typhoid fever). When people eat food contaminated by S. enteritidis, they suffer from inflammation of hte stomach and intestines, with diarrhea and vomiting resulting. This illness is called gast…

2 minute read

Salt

Salt, the most commonly known of which is sodium chloride, or table salt, is a compound formed by the chemical reaction of an acid with a base. During this reaction, the acid and base are neutralized producing salt, water and heat. Sodium chloride, is distributed throughout nature as deposits on land created by the evaporation of ancient seas and is also dissolved in the oceans. Salt is an importa…

2 minute read

Saltwater

Saltwater, or salt water, is a geological term that refers to naturally occurring solutions containing large concentrations of dissolved, inorganic ions. In addition, this term is often used as an adjective in biology, usually to refer to marine organisms, as in saltwater fish. The ions with the largest concentrations in marine waters are sodium, chloride, sulfate, magnesium, calcium, potassium, a…

2 minute read

Sand

Sand is any material composed of loose, stony grains between 1/16 mm and 2 mm in diameter. Larger particles are categorized as gravel, smaller particles are categorized as silt or clay. Sands are usually created by the breakdown of rocks, and are transported by wind and water, before depositing to form soils, beaches, dunes, and underwater fans or deltas. Deposits of sand are often cemented togeth…

4 minute read

Sand Dollars

Sand dollars or sea biscuits (phylum Echinodermata, class Echinoidea) are closely related to heart urchins and sea urchins, although they lack the visible long, protective spines of the latter. The body is flattened and almost circular in appearance—an adaptation for burrowing in soft sediment. It is protected by a toughened exterior known as the test, and is covered with short spines. The …

1 minute read

Sandfish

A sandfish is a sand-dwelling lizard of the family Scincidae (a skink) found in desert regions of North Africa and southwestern Asia. It receives the name "sandfish" because it literally "swims" through the loose sand of its preferred habitat. Six or seven species of the genus Scincus are called sandfish. They range from Algeria, in northwestern Africa, to the Sind dese…

1 minute read

Sandpipers

Sandpipers are a varied group of shore birds in the family Scolopacidae, order Charadriiformes. The 85 species in this family include the sandpipers, curlews, snipes, woodcocks, godwits, dowitchers, turnstones, and phalaropes. With the exception of Antarctica, this family occurs worldwide. Thirty-seven species in the sandpiper family breed regularly in North America. The smaller species of sandpip…

5 minute read