Science & Philosophy: Cluster compound to Concupiscence
Coatis
Coatis are raccoon-like mammals in the family Procyonidae, which have a long ringed tail, typically held perpendicular to the body, and a flexible, upturned, elongated snout. Coatis are also distinctive socially. The females live together in highly organized groups called bands, composed of 5-12 allied individuals, while adult males are solitary. The difference in the social patterning of the sexe…
Coca
The coca plant, genus Erythroxylum, family Erythroxylaceae, order Linales, is native to the Andean slopes of South America. The genus Erythroxylum comprises approximately 250 species, of which the most cultivated species are Erythroxylum coca (southern Peru and Bolivia) and Erythroxylum novogranatense ( Colombia and northern coastal Peru). The coca plant is a shrub, growing to about 15 ft (5 m). C…
Cocaine - History, Introduction To The West, Coca-cola, Early Drug Laws, After The 1960s
Cocaine is a colorless or white narcotic crystalline alkaloid derived from the leaves of the South American coca plant—Erythroxylum coca. Aside from its use as a local anesthetic, which has largely been supplanted by safer drugs, its medical applications failed to live up to the hopes of physicians and chemists of the late nineteenth century. They administered cocaine to themselves and othe…
Cockatoos
Cockatoos are species of birds in the family Cacatuidae, in the order Psittaciformes, which also contains the typical parrots (family Psittacidae). Parrots and cockatoos all have powerful, curved bills, short legs, and strong, dexterous feet with two toes pointing forward and two backward. These birds also have specialized feathers known as powder down, which disintegrates into a powder that is us…
Cockroaches
Cockroaches are insects in the order Blattaria. They are somewhat flat, oval shaped, leathery in texture, and are usually brown or black in color. Cockroaches range in body size from 0.1 to 2.3 in (2.5 to 60 mm), and are rampant pest insects in human inhabited areas, as well as common outdoor insects in most warm areas of the world. These insects were formerly classified in the order Orthoptera, w…
Codeine
Codeine is a type of medication belonging to a class of drugs known as opioid analgesics, which are derived from the Papaver somniferum, a type of poppy flower, or are manufactured to chemically resemble the products of that poppy. In Latin, Papaver refers to any flower of the poppy variety, while somniferum translates to mean "maker of sleep." The plant has been used for over 6,000 …
Codfishes - Atlantic cod and its fishery
Codfish (family Gadidae) are a family of bottom-feeding fish that live in cool or cold seas, mostly in the Northern Hemisphere. There are about 21 genera and 55 species of codfishes. The most commonly utilized marine habitats are inshore waters and continental shelves, generally in depths of less than about 300 ft (100 m), but sometimes considerably deeper. Codfishes are voracious predators of sma…
Codons
Information for the genetic code is stored in a sequence of three nucleotide bases of DNA called base triplets, which act as a template for which messenger RNA (mRNA) is transcribed. A sequence of three successive nucleotide bases in the transcript mRNA is called a codon. Codons are complimentary to base triplets in the DNA. For example, if the base triplet in the DNA sequence is GCT, the correspo…
Coelacanth - astonishing find The first
The coelacanth (Latimeria chalumnae) is the only living representative of an ancient order of fishes, until recently thought to have become extinct 70 million years ago, at about the same time as the dinosaurs. In 1938, however, scientists were astonished when living coelacanths were discovered (this is described later). The coelacanth is a sarcoptergian, or lobe-finned fish, distantly related to …
Coffee Plant - Cultivation And Harvesting, History
The coffee tree, genus Coffea, family Rubiaceae (Madder family), is native to Ethiopia. The name coffee also refers to the fruit (beans) of the tree and to the beverage brewed from the beans. Coffee is one of the world's most valuable agricultural crops. There are about 30 species of Coffea, but only two species provide most of the world market for coffee. Coffea arabica is indigenous to Et…
Cogeneration - Why Cogenerate?, History Of Cogeneration, Barriers To Cogeneration, Current Research
Cogeneration is the simultaneous generation of two forms of energy, usually heat and electricity, from one energy source. Traditional energy generating systems produce only heat or electricity by burning a fuel source. In both cases, burning the fuel generates a lot of heat and the exhaust gases can be hotter than 932°F (500°C). Traditionally, this "waste heat" would be…
Common Cold
The common cold, also often referred to as an upper respiratory infection, is caused by some 200 different viruses, and has defied both cure and vaccine for centuries. The United States alone will have about a half a billion colds a year, or two for each man, woman, and child. Dedicated researchers have searched for a cure or even an effective treatment for years. The pharmaceutical company that d…
Colloid
A colloid is a type of particle intermediate in size between a molecule and the type of particles we normally think of, which are visible to the naked eye. Colloidal particles are usually from 1 to 1,000 nanometers in diameter. When a colloid is placed in water, it forms a mixture which is similar in some ways to a solution, and similar in some ways to a suspension. Like a solution, the particles …
Colobus Monkeys - Black And White Colobus Monkeys, Red Colobus Monkeys
Colobus monkeys and the closely related langurs and leaf monkeys are Old World monkeys in the sub-family Colobinae of the family Cercopithecidae. The primates in this subfamily share a common trait—they lack thumbs or have only small, useless thumbs. (The name colobus comes from a Greek word meaning mutilated.) However, lack of a thumb does not stop them from nimbly moving among the branche…
Colonialism - Africa - Colonialism In African History, The Nature Of The Colonial Encounter, The Bifurcated Colonial State, Dependent Colonial Capitalism
Conceptions and characterizations of colonialism vary considerably among scholars of Africa. Differences and debates center on four sets of interrelated issues: first, the place and importance of the colonial period in African history; second, the nature of the colonial encounter and its driving force; third, the typologies of African colonialism; and fourth, the legacies of colonialism for postco…
Colonialism - Latin America - Bibliography
Colonialism is all about the exercise of power and its consequences. Theoretically, the exercise of power entails the interaction of at least two parties negotiating (by various means or practices) their wills on one or more issues, as shown by their various actions or statements. This definition holds for interactions of both individuals and institutions. The imposition of one state's will…
Colonialism - Southeast Asia - Historical Overview, Trends In The Study Of Colonialism, Colonialism Since 1970, Colonial Dichotomies, Trends In The Late 1990s And Early 2000s
Studies detailing the nature of colonial policy and practice in Southeast Asia have all acknowledged its disparate nature and overwhelming range of characteristics. While many European powers shared the desire to establish colonies overseas, the manner in which this was accomplished was more random than regular. Factors contributing to this variance include differing philosophies of administrative…
Color - Light And Color, Rainbows, Refraction: The Bending Of Light, Diffraction And Interference, Transparent, Translucent, And Opaque
Color is a complex and fascinating subject. Several fields of science are involved in explaining the phenomenon of color. The physics of light, the chemistry of colorants, the psychology and physiology of human emotion are all related to color. Since the beginning of history, people of all cultures have tried to explain why there is light and why we see colors. Some people have regarded color with…
Colugos - Characteristics, Flightskin, Behavior, Reproduction, Threats To Colugos
A colugo is a furry mammal with a thin neck, a slender body, and large eyes. It is about the size of an average house cat, measuring between 15-16.5 in (38-42 cm) long with a tail adding another 8-10 in (20-25 cm). Also known as a flying lemur, the colugo neither truly flies nor is it a lemur. A gliding mammal, it is able to give the appearance of flight with the help of a membrane that stretches …
Combinatorics - History Of Combinatorics, Enumeration, Binomial Coefficients, Equivalence Relations, Recurrence Relations, Graph Theory
Combinatorics is the study of combining objects by various rules to create new arrangements of objects. The objects can be anything from points and numbers to apples and oranges. Combinatorics, like algebra, numerical analysis and topology, is a important branch of mathematics. Examples of combinatorial questions are whether we can make a certain arrangement, how many arrangements can be made, and…
Comet Hale-Bopp - Streaking across the heavens
In the spring of 1997, the night sky provided a spectacular light show as Comet Hale-Bopp, one of the brightest comets of the century, traversed the heavens. The comet was more closely studied than any before it, and scientists continue to make discoveries based on the data gathered by terrestrial and orbital telescopes and instrumentation. Originating primarily from the Oort Cloud, a belt of stel…
Comets - Age-old Fascination, Stargazing And Discovering Comets, Comets And Earth, Bright Objects Keep Us In The Dark - origin Composition and extinction
A comet is an object with a dark, solid core (the nucleus) some miles in diameter. The core is composed mostly of water ice and frozen gas and is surrounded—whenever the comet is close enough to the Sun for part of the core to vaporize—by a cloud of glowing vapor (the coma). Together, the core and coma comprise the comet's head, which appears as a bright, well-defined cloud. A…
Commensalism
Commensalism is a type of symbiosis, specifically, a biological relationship in which one species benefits from an interaction, while the host species is neither positively or negatively affected to any tangible degree. For example, epiphytic plants (which grow on other plants but are not parasitic) gain an enormous ecological benefit from living on larger plants, because they gain access to a sub…
Common Sense - Bibliography
The common-sense philosophers of the Scottish school—including Thomas Reid, Dugald Stewart, James Beattie, George Campbell, and James Oswald—argued against George Berkeley and David Hume that ordinary human perception and moral judgment need not be defended against skeptical inquiry but ought to be taken as self-evident. As Campbell put it, "to maintain propositions the revers…
Communication in Africa and its Influence - Orality And Performance, Written Communication, The Development Of Modern Media, Africa And Its Influence
The communication of ideas in and from Africa is characterized by enormous changes over time and variations among societies. Historically, as might be expected for such a large and ancient continent—the second largest in the world and the one where humanity originated—African societies have exhibited high levels of cultural diversity, uneven patterns of political and socioeconomic de…
Communication in Asia and its Influence - Language Issues, English And Sanskrit, Trade And The Exchange Of Ideas, Conquest, Invasion, And Emigration
Asia comprises a vast amount of land divided into numerous countries, many of which have civilizations dating back thousands of years. Due to the huge scope of this topic, this entry will focus on India as an important hub for the transmission of ideas throughout Asia and how other Asian countries influenced the development of Indian civilization. When India became independent in 1947, the new gov…
Communism in Europe - Karl Marx And The Origins Of Modern Communism, Non-marxist Communism, Marxism And European Socialism
"A spectre is haunting Europe—the spectre of Communism." The famous opening line to The Communist Manifesto evokes the expectations and fears that have been associated with European communism. Published in 1848 amid a tumultuous period of political unrest across the continent, this polemical pamphlet was an idealistic call to arms directed at an emerging male working class (&#…
Communism in Latin America - Anticommunism In Latin America, The Cuban Model, Guerrilla Insurgents, Democratic Transition, Conclusion, Bibliography
Latin America in the 1890s was a society primed for the dissemination of socialist ideologies. It was ruled by autocrats and oligarchs who were exploiting an increasingly discontented peasant populace and perpetuating a sharply divided two-class social structure. During this time, increased productivity and foreign investment ushered in the earlier stages of exploitative capitalism as well as a wa…
Communitarianism in African Thought - Menkiti On Communitarianism, Gyekye On Moderate Communitarianism, Bibliography
This essay explores representative Africanist thought on personhood and community, highlighting especially the debate between Ifeanyi Menkiti and Kwame Gyekye on communitarianism, defined generally as relating to social organization in small, cooperative, partially collectivist communities. The general debate on these issues in Africa can be traced to important studies of personhood and psychology…
Community Ecology
Within the science of ecology, a community is a set of organisms coexisting within a defined area. Community ecology, then, is the study of the interactions that occur among groups of species coexisting within a region. For example, a community ecologist might consider the ways in which plants and animals within a forest affect one another's growth. Contrary to popular usage, the term ecolo…
Commutative Property
"Commutativity" is a property an operation between two numbers (or other mathematical elements) may or may not have. The operation is commutative if it does not matter which element is named first. For example, because addition is commutative, 5 + 7 has the same value as 7 + 5. Subtraction, on the other hand, is not commutative, and the difference 5 - 7 does not have the same value a…
Compact Disc - Manufacture Of A Compact Disc, Retrieving Information From A Disc, Drive Specifications, Care Of Cd-roms - CD-ROM drives, Drive formats, Interfaces, Nonstandard SCSI interfaces
In 1978, Philips and Sony together launched an effort to produce an audio compact disc (CD) as a method of delivering digital sound and music to consumers. The two companies continued to cooperate through the 1980s and eventually worked out standards for using the CD technology to store computer data. These recommendations evolved into the CD-ROM technology of today. The CD-ROM (compact disc-read …
Competition - Competition as an ecological and evolutionary factor
Competition is a biological interaction among organisms of the same or different species associated with the need for a common resource that occurs in a limited supply relative to demand. In other words, competition occurs when the capability of the environment to supply resources is smaller than the potential biological requirement so that organisms interfere with each other. Plants, for example,…
Complementary DNA
Complementary deoxyribonucleic acid (DNA) is DNA in which the sequence of the constituent molecules on one strand of the double stranded structure chemically matches the sequence on the other strand. A useful analog is to picture a key and a lock. While there are many different types of keys, only one design matches the contours of the lock and so will fit into the lock. The different chemical mol…
Complex
A complex is a species in which the central atom is surrounded by a group of Lewis bases that have covalent bonds to the central atom. The Lewis bases that surround the central atom are generally referred to as ligands. Complexes are so named because when they were first studied, they seemed unusual and difficult to understand. Primarily, transition metals form complexes and their most observable …
Complex Numbers - Arithmetic, Graphical Representation, Uses Of Complex Numbers
Typical complex numbers are 3 - i, 1/2 + 7i, and -6 - 2i. If one writes the real number 17 as 17 + 0i and the imaginary number -2.5i as 0 - 2.5i, they too can be considered complex numbers. Complex numbers are so called because they are made up of two parts which cannot be combined. Even though the parts are joined by a plus sign, the addition cannot be performed. The expression must be left as an…
Composite Family (Compositaceae) - Characteristics Of The Asteraceae, Horticultural Species, Agricultural Species Of Composites, Other Useful Species Of Composites
The composite or aster family (Asteraceae) is one of the largest families of plants, containing about 20,000 species, distributed among more than 1,000 genera, and occurring widely on all continents, except Antarctica. This family is commonly regarded by modern botanists as the most advanced of the plant families, because of the complex, highly evolved structure of its multi-flowered, composite re…
Composite Materials - Particle-reinforced Composites, Fiber-reinforced Composites, Laminar Composites, Mechanical Properties, Other Composites - High performance composites
A composite material is a microscopic or macroscopic combination of two or more distinct materials with a recognizable interface between them. For structural applications, the definition can be restricted to include those materials that consist of a reinforcing phase such as fibers or particles supported by a binder or matrix phase. Other features of composites include the following: (1) The distr…
Musical Composition - Cultural Roles, Changing Definitions, Conclusion, Bibliography
The term composition (from the Latin com, together, and ponere, to put) is commonly applied in Western music to a notated work, and in non-Western systems to a consistently united progression or organization of sounds. Although Western music compositions have been defined by their narrative structure (i.e., progression toward a climax, etc.) a more accurate definition, encompassing modern Western …
Composting - History, Composting On Any Scale, Materials To Compost, How It Works, The Chemical Process
Composting is the process of arranging and manipulating organic wastes so that they are gradually broken down, or decomposed, by soil microorganisms and animals. The resulting product is a black, earthy-smelling, nutritious, crumbly mixture called compost or humus. Compost is usually mixed with other soil to improve the soil's structural quality and to add nutrients for plant growth. Compos…
Chemical Compound - Non-chemical Definitions, History, Early Theories Of Compounds, Modern Theory Of Compounds, Types Of Compounds
A compound is a substance composed of two or more elements chemically combined with each other. Historically, the distinction between compounds and mixtures was often unclear. Today, however, the two can be distinguished from each other on the basis of three primary criteria. First, compounds have constant and definite compositions, while mixtures may exist in virtually any proportion. A sample of…
Compton Effect
The Compton effect (sometimes called Compton scattering) occurs when an x ray collides with an electron. In 1923, Arthur H. Compton did experiments bouncing x rays off the electrons in graphite atoms. Compton found the x rays that scattered off the electrons had a lower frequency (and longer wavelength) than they had before striking the electrons. The amount the frequency changes depends on the sc…
Compulsion - Obsessive-compulsive Disorder (ocd), Obsessive-compulsive Personality Disorder, Treatments For Obsessive-compulsive Illnesses
The main concern of psychiatrists and therapists who treat people with compulsions is the role they play in a mental illness called obsessive-compulsive disorder (OCD). Compulsions need to be distinguished from obsessions in order to understand how they interconnect with compulsive behavior and reinforce this debilitating illness. In psychiatric literature, compulsions are defined as repetitive be…
Analog Computer
A digital computer employs physical device states as symbols; an analog computer employs them as models. An analog computer models the behaviors of smoothly varying mathematical variables—usually representing physical phenomena such as temperatures, pressures, or velocities—by translating these variables into (usually) voltages or gear movements. It then manipulates these physical qu…
Digital Computer
A digital computer is a programmable device that processes information by manipulating symbols according to logical rules. Digital computers come in a wide variety of types, ranging from tiny, special-purpose devices embedded in cars and other devices to the familiar desktop computer, the minicomputer, the mainframe, and the supercomputer. The fastest supercomputer, as of early 2003, can execute u…
Computer Languages - First-generation Language, Second-generation Language, Third-generation Language, Fourth-generation Language
A computer language is the means by which instructions and data are transmitted to computers. Put another way, computer languages are the interface between a computer and a human being. There are various computer languages, each with differing complexities. For example, the information that is understandable to a computer is expressed as zeros and ones (i.e., binary language). However, binary lang…
Physical Computer Memory and Virtual Memory
Physical and virtual memory are forms of memory (internal storage of data). Physical memory exists on chips (RAM memory) and on storage devices such as hard disks. Before a process can be executed, it must first load into RAM physical memory (also termed main memory). Virtual memory is a process whereby data (e.g., programming code,) can be rapidly exchanged between physical memory storage locatio…
Computer Science - Early History, Computer Science Chronology, Basic Methodologies Of The Field, Some Examples Of Computer Science Merging With Other Fields
The field called computer science was born in the 1940s, though its roots extend back to the nineteenth century and even earlier. One of the early founders of the field was Alan Turing (1912–1954), a citizen of Great Britain, who in 1937 published his famous paper entitled "On Computable Numbers with an Application to the Entscheidungsproblem." In this paper he introduced the …
Computer Software - Origin Of Computer Software, Modern Day Computer Software, The Language Of Software, Application Software
Computers are built of electronic components encased in a sturdy metal container and attached to the outside of the container. Examples of hardware include electrical connections, circuit boards, hard and disk drives, viewing monitor, and printer. The components and the container are referred to as hardware. On their own, computer hardware is functionally useless. For the electronic circuitry to b…
Computer Virus
A computer virus is a program or segment of executable computer code that is designed to reproduce itself in computer memory and, sometimes, to damage data. Viruses are generally short programs; they may either stand-alone or be embedded in larger bodies of code. The term "virus" is applied to such code by analogy to biological viruses, microorganisms that force larger cells to manuf…
Computerized Axial Tomography
Computerized axial tomography (CAT) is a diagnostic procedure that employs x rays in a unique manner. The CAT scan machine is computer controlled to assure accuracy in placement of the x-ray beam. Axial refers to the fact that the x-ray tubes are arranged in an arc about an axis. Tomography is a combination of tomo, from the Greek meaning "to cut," and graph, "to draw,"…
Concentration
Concentration is a ratio of how much of one ingredient is present in a mixture, compared to the whole mixture or compared to the main ingredient, often the solvent. The amounts of each substance can be expressed in mass or volume units, and many different units can be used. The components of the mixture can be gases, liquids, or solids. Earth's atmosphere, for example, is a mixture of gases…
Concrete
Concrete, from the Latin word concretus meaning "having grown together," generally consists of Portland cement, water, and a relatively unreactive filler called aggregate. The filler is usually a conglomerate of gravel, sand, and blast-furnace stony matter known as slag. When Portland cement is mixed with water, the various ingredients begin to react chemically with the water. For a …