The chimaeras (order Chimaerae, class Bradyodonti) are a most peculiar looking group of fish that live near the sea bed off continental shelves and in deep offshore waters at a depth of 985-1,640 mi (300-500 m). Collectively these species form a small, cohesive group of about 25 species. They are all exclusively marine species. Closely related to sharks, rays, and dogfish, chimaeras are characteri…
Chinchillas and viscachas are seven species of small, South American rodents in the family Chinchillidae. Chinchillas have a large head, broad snout, large eyes, rounded ears, and an extremely fine and dense fur. Their forelimbs are short and the paws small, while the hindlegs and feet are larger and relatively powerful, and are used for a leaping style of locomotion, as well as for running and cr…
The term mysticism represents a modern approach to a cultural path rooted in antiquity, and given anthropological considerations it is timeless. Mysticism usually concerns any work, study, or praxis that aims at transcendence (the experiencing "self" moving beyond normal limits) or union with the divine. It was (is) often private or even secret, perhaps involving special teachers. To…
Chinese thought is a generic term, referring to the ideas produced, expanded, and transmitted in the history of China. First, these ideas are not simply general opinions, but the philosophical views of the world, life, and society that have been commonly accepted as concepts or systematic theories. These ideas or theories are the end-products of logical reasoning—in Chinese, the two charact…
The term junfa became part of the Chinese vocabulary in the 1910s and gained popularity in the 1920s to describe the phenomenon of militarism that dominated the Chinese political scene between 1916 and 1928. While both characters, jun (military) and fa (as in menfa, prominent lineage), are ancient Chinese words, it was in Japan that fa as a suffix was paired with other words to mean "a cliq…
Chipmunks are small mammals in the order Rodentia, the rodents. Specifically, they are classified with the squirrel-like rodents, the Sciuridae. Chipmunks are divided into two genera: Gallos and Tamias. North America is home to 17 species of chipmunk, 16 in the West and only one, Tamias striatus, the eastern chipmunk, in the East. The eastern chipmunk is about 5-6 in (12.7-15 cm) long, and the tai…
Chitons are small mollusks, oval in outline, with a broad foot, and a mantle that secretes, and sometimes extends over, the shell. They live on rocky seashores in much the same life-style as limpets. They are easily distinguishable from limpets, however, by their shell made of eight plates (or valves) with transverse sutures. Also, unlike limpets and other snails, the chitons have no tentacles or …
Chlordane is an organochlorine insecticide, more specifically a chlorinated cyclic hydrocarbon within the cyclodiene group. The proper scientific name for chlordane is 1,2,4,5,6,7,8,8-Octachloro-3a,4,7,7a-tetrahydro-4,7-methanoindan. However, the actual technical product is a mixture of various chlorinated hydrocarbons, including isomers of chlordane and other closely related compounds. The first …
A very large and diverse group of organic molecules are chlorinated hydrocarbons. Hydrocarbons are molecules composed entirely of hydrogen and carbon atoms, often derived from carbon-based fossil fuels like petroleum oils and coal. Chlorinated hydrocarbons are specific hydrocarbon molecules that also have atoms of the element chlorine chemically bonded to them. The number of chlorine atoms bonded …
Chlorination is the process by which the element chlorine reacts with some other substance. Chlorination is a very important chemical reaction both in pure research and in the preparation of commercially important chemical products. For example, the reaction between chlorine and methane gas produces one or more chlorinated derivatives, the best known of which are trichloromethane (chloroform) and …
Chlorine is the non-metallic chemical element of atomic number 17, symbol Cl, atomic weight 35.45, melting point -149.8°F (-101°C), and boiling point -29.02°F (-33.9°C). It consists of two stable isotopes, of mass numbers 35 and 37. Ordinary chlorine is a mixture of 75.77% chlorine-35 atoms and 24.23% chlorine-37 atoms. Chlorine is a highly poisonous, greenish yellow ga…
Chlorofluorocarbons (CFCs) are man-made chemical compounds used as refrigerants, cleaning solvents, aerosol propellants, and blowing agents for foam packaging in many commercial applications. CFCs do not spontaneously occur in nature. They were developed by industrial chemists searching for a safer alternative to refrigerants used until the late 1920s. CFCs are non-toxic, chemically non-reactive, …
Chloroform was originally used to calm people suffering from asthma. In 1847, James Y. Simpson, a Professor of Midwifery at the University of Edinburgh, began using chloroform as an anesthetic to reduce pain during childbirth. From this initial experiment, chloroform began to be used as general anesthesia in medical procedures throughout the world. The use of chloroform in this application was eve…
Chlorophyll is a green pigment contained in the foliage of plants, giving them their notable coloration. This pigment is responsible for absorbing sunlight required for the production of sugar molecules, and ultimately of all biochemicals, in the plant. Chlorophyll is found in the thylakoid sacs of the chloroplast. The chloroplast is a specialized part of the cell that functions as an organelle. O…
Chloroplasts are organelles—specialized parts of a cell that function in an organ—like fashion. They are found in vascular plants, mosses, liverworts, and algae. Chloroplast organelles are responsible for photosynthesis, the process by which sunlight is absorbed and converted into fixed chemical energy in the form of simple sugars synthesized from carbon dioxide and water. Chloroplas…
Chordates are a diverse group of animals that comprise the phylum Chordata. There are approximately 44,000 species of chordates, ranging in size from several millimeters to 105 ft (32 m) long. The simplest and earliest chordates are pre-vertebrate animals such as ascidians, tunicates, and Amphioxus. The major group of chordates are the sub-phylum Vertebrata, the vertebrates. Listed more-or-less in…
Chorionic villus sampling (CVS) is a relatively new form of a prenatal testing, completed earlier in gestation than the more traditional testing method, amniocentesis. Through CVS, small samples of the trophoblast are obtained for chromosome or DNA analysis. The use of CVS as a tool for fetal karyotyping at 10 weeks' gestation was introduced in 1969 but it became accepted with the introduct…
Since the Baroque age, the concept of mysticism (first in French, la mystique) has been used to describe religious phenomena that can hardly be restricted to a certain geographical space or a certain epoch. These phenomena are primarily symbolic expressions (in act, speech, literature, art, music, etc.), of persons trying to communicate knowledge that has been gained through mystical experiences. …
Since the 1970s, the study of Christianity in Asia has been transformed by new approaches in which the scholarly perspective has become less Eurocentric and more Asian. Particularly in regard to China, Western missionary sources have given way to Chinese sources while the meaning of Christianity has been broadened beyond a narrow religious content to include Asian cultural elements. The history of…
According to the writers of the Gospels, Jesus of Nazareth gathered a small group of disciples and went about for three years in first century Galilee, preaching a message of hope to the poor and healing the sick. John the "Baptist" had gone before him, calling people to repent and be baptized, promising the imminent coming of the Kingdom of Heaven. He recognized in Jesus a far great…
Chromatin is the masses of fine fibers comprising the chromosomes in the nucleus of a eukaryotic cell in a nondividing state. During cell division (mitosis or meiosis) the chromatin fibers pull together into thick shortened bodies which are then called chromosomes. Chromatin is present only in cells with a nuclear membrane; it is not found in prokaryotic cells (e.g., bacteria) that lack a nucleus.…
Chromatography is a family of laboratory techniques for separating mixtures of chemicals into their individual compounds. The basic principle of chromatography is that different compounds will stick to a solid surface, or dissolve in a film of liquid, to different degrees. To understand chromatography, suppose that all the runners in a race have sticky shoe soles, and that some runners have sticki…
Chromosome abnormalities describe alterations in the normal number of chromosomes or structural problems within the chromosomes themselves. Both kinds of chromosome abnormalities may result from an egg (ovum) or sperm cell with the incorrect number of chromosomes, or with a structurally faulty chromosome uniting with a normal egg or sperm during conception. Some chromosome abnormalities may occur …
Chromosome mapping is the assignment of genes to specific locations on a chromosome. A gene map serves many important functions and is much like understanding the basic human anatomy to allow doctors to diagnose patients with disease. A doctor requires knowledge of where each organ is located as well as the function of this organ to understand disease. A map of the human genome will allow scientis…
The World Health Organization (WHO) has named tobacco one of the greatest public health threats of the twenty-first century. As of 2001, more than 1.2 billion people worldwide smoke, and 3.5 million people are expected to die from causes directly related to tobacco use. This death rate is expected to rise to 10 million by the year 2030. Seventy percent of these deaths will occur in developing coun…
The latter half of the twentieth century witnessed a swift decline in the popularity and significance of cinemagoing in the West, associated with suburbanization and the rise of competitor media like rock and roll and television. From the 1990s, cinema release was repositioned as a cornerstone of multimedia-themed product lines, including alternative forms of distribution and exhibition (in-flight…
Living things require a circulatory system to deliver food, oxygen, and other needed substances to all cells, and to take away waste products. Materials are transferred between individual cells and their internal environment through the cell membrane by diffusion, osmosis, and active transport. During diffusion and osmosis, molecules move from a higher concentration to a lower concentration. Durin…
The terms circumscribed and inscribed refer, respectively, to geometric figures that have been drawn around the outside of or within some other geometric figure. For example, imagine that a circle is drawn around a triangle so that the circle passes through all three vertices of the triangle. Then the circle is said to be circumscribed around the triangle, and the triangle is said to be inscribed …
Cirrhosis is a degenerative liver disease in which the lobes of the liver become infiltrated with fat and fibrous tissue (fibrous tissue is a type of connective tissue composed of protein fibers called collagen). The word "cir rhosis" is derived from the Greek words kirrhos, meaning "yellowish orange" and osis, meaning "condition," and connotates the appea…
Citizenship consists in sharing a political community, and enjoying the benefits and assuming the political responsibilities that give effect to this experience of shared political community. If the purpose of political philosophy is to provide a principled account of the nature and appropriate boundaries of political community, then it makes sense to say that the tradition of political philosophy…
Citric acid is an organic (carbon based) acid found in nearly all citrus fruits, particularly lemons, limes, and grapefruits. It is widely used as a flavoring agent, preservative, and cleaning agent. The structure of citric acid is shown below. The COOH group is a carboxylic acid group, so citric acid is a tricarboxylic acid, possessing three of these groups. Citric acid helps to provide the �…
Citrus trees are various species of trees in the genus Citrus, in the rue family, or Rutaceae. There are 60 species in the genus Citrus, of which about 10 are used in agriculture. The center of origin of most species of Citrus is southern and southeastern Asia. Citrus trees are widely cultivated for their edible fruits in sub-tropical and tropical countries around the world. The sweet orange (Citr…
From the early days of urbanization, several often competing conceptions of cities were evident: As a unit of analysis the city is often characterized through the emphasis on diversity, fragmentation, strangeness, encounters with strangers, the mosaic of variety, contingent interactions, moving borders, everyday life and events, and the multitude of interactions. However, another perspective focus…
Small to medium-sized carnivores, civets are in the Viverridae family which includes genets, linsangs, and mongooses. There are 35 species of civets and genets in 20 genera. Their natural distribution is restricted to the warmer regions of the Old World, and they occupy a niche similarly filled by weasels and their relatives found in temperate deciduous forests. Civets vary in size and form, but m…
Civil disobedience is an illegal act performed publicly in contravention of a law or laws of the government for the short-term purpose of bringing about a change in the law or laws and for the long-term purpose of improving society as a whole. It is a political act because its underlying principles are the principles of political justice that regulate the state and its institutions, and not those …
The next neoclassical period, which we call the Renaissance, exploded in Italy under the patronage of such personages as the Medicis and Pope Leo X. The Renaissance with its focus on secular life, fortified by the availability of the important literary works of the Romans and by translations of the Greeks into Latin, sometimes via Arabic, and then by the study of Greek, enabling educated people to…
Climax is a theoretical, ecological notion intended to describe a relatively stable community that is in equilibrium with environmental conditions, and occurring as the terminal, end-point of succession. One of the early proponents of the concept of climax was the American ecologist, Frederic Clements. In an important publication in 1916, he theorized that there was only one true climax community …
Clingfish are about 100 species of small, ray-finned bony fish found primarily in tropical marine waters. They belong to the family Gobiesocidae in the order Gobiesociformes. Clingfish are shaped like tadpoles with a wide, flattened head; they have no scales and are covered with a thick coating of slime that makes them very slippery. Clingfish are characterized by a large suction disc formed by th…
A closed curve is one which can be drawn without lifting the pencil from the paper and which ends at the point where it began. In Figure 1, A, B, and C are closed curves; D, E, and F are not. Curve A is a circle. Although the starting point is not indicated, any of its points can be chosen to serve that purpose. Curve B crosses itself and is therefore not a "simple" closed curve, but…
"Closure" is a property which a set either has or lacks with respect to a given operation. A set is closed with respect to that operation if the operation can always be completed with elements in the set. For example, the set of even natural numbers, 2, 4, 6, 8,..., is closed with respect to addition because the sum of any two of them is another even natural number. It is not closed …
All clouds are a form of water. Clouds are condensed atmospheric moisture in the form of minute water droplets or ice crystals. The creation of a cloud begins at ground level. The sun heats the earth's surface, the warm ground heats the air, which rises. The air contains variable amounts of water, as vapor, that has evaporated from bodies of water and plants. Air at ground level is denser t…
Club mosses, also called lycophytes, are flowerless and seedless plants in the family Lycopodiaceae, that belong to an ancient group of plants of the division Lycophyta. The lycophytes were one of the dominant plants during the Coal age (360-286 million years ago) and many were shrubs or large trees. By 250 million years ago, most of the woody species had died out. Between 10 and 15 living genera …