Science & Philosophy: Macrofauna to Mathematics

Science Encyclopedia

Magic - Magic, Religion, And Science, The Functions And Effects Of Magic In Classic Anthropological Works

Magic is the performance of acts or rites that are intended to influence a person, object, or event. It can also be performed to counter other magic. Magical acts or rites are usually performed with the assistance of mystical power. People who engage in the different activities magic encompasses can be called magicians, shamans, healers, sorcerers, or priests/priestesses. In some societies the kno…

2 minute read

Magic Square

Magic square is an unusual numerical configuration containing consecutive integers in arrangements so that the sum of numbers in any row, column, or diagonal are identical. Such squares were known approximately 4,000 years ago in China. The basic magic square is a square containing consecutive integers starting with number 1. Three of the basic magic squares are shown in Table 1. Other magic …

1 minute read

Magma

In geology, magma refers to molten rock deep within Earth that consists of liquids, gases, and particles of rocks and crystals. Magma has been observed in the form of hot lava and the various rocks made from the solidification of magma. Geologists have created magmas (artificial melts) in the laboratory to learn more about the physical conditions in which magma originated and its composition. Magm…

2 minute read

Magnesium

Magnesium (Mg) is one of the most abundant structural metals (those metals used to build things), ranking third behind iron and aluminum. Magnesium compounds are found in mineral rocks such as dolomite and magnesite, while the Earth's oceans contain a practically unlimited supply of the metal in the form of dissolved magnesium chloride. One cubic mile of seawater holds some six million tons…

3 minute read

Magnetic Resonance Imaging (MRI)

Magnetic resonance imaging (MRI) is a medical technique which utilizes a magnetic field and the natural An example of a magnetic resonance imaging system (MRI). Photograph by Mason Morfit. FPG International Corp. Reproduced by permission. resonance of atoms to provide an image of human tissue. While the foundation for its development first took place in the late 1930s, it was not unt…

4 minute read

Magnetism - History Of Magnetism, Origin Of Magnetism, Types Of Magnetism, Measurement Of Magnetic Field, Applications Of Magnetism

Magnetism is a force generated in matter by the motion of electrons within its atoms. Magnetism and electricity represent different aspects of the force of electromagnetism, which is one part of Nature's fundamental electroweak force. The region in space that is penetrated by the imaginary lines of magnetic force describes a magnetic field. The strength of the magnetic field is determined b…

less than 1 minute read

Magnetosphere

The magnetosphere is a comet-shaped region of Earth's outer atmosphere in which the behavior of Earth's magnetosphere. Illustration by Hans & Cassidy. Courtesy of Gale Group. charged particles is strongly influenced by magnetic and ionic phenomena. The term was first introduced by the British astronomer Thomas Gold in 1959 although speculation about the existence of suc…

2 minute read

Magnolia

Magnolias are species of trees and woody shrubs that comprise the family Magnoliaceae. This is an ancient and relatively primitive group of dicotyledonous plants with fossil materials known from as early as the Upper Cretaceous. The magnolia family contains about 220 species in 12 genera, including the true magnolias (Magnolia spp.), with about 100 species. Magnolias have seasonally deciduous or e…

1 minute read

Mahogany - Biology Of Mahogany, Uses Of Mahogany, Some Related Species

Mahogany (Swietenia mahogani) is a member of the family Meliaceae, which contains about 500 other species of trees and shrubs native to tropical forests in the Americas, Africa, and Asia. Other common names for this species are the Spanish or West Indies mahogany. Various other species of trees have also been given the name mahogany, but the true mahogany is Swietenia mahogani. Mahogany is one of …

1 minute read

Maidenhair Fern

These are a group of ferns found in tropical and warm temperate regions. They are characterized by having delicate, fan-shaped fronds, arising from a thin black midrib, with small green leaflets. Maidenhair fern belong to the genus Adiantum, and some species are popular as house plants. In North America there are three common species, the northern maidenhair fern (A. pedatum), the southern maidenh…

1 minute read

Malnutrition - Overnutrition, Causes And Symptoms, Diagnosis, Treatment, Prognosis, Prevention

Malnutrition is the condition that develops when the body does not get the right amount of the vitamins, minerals, and other nutrients it needs to maintain healthy tissues and organ function. Malnutrition occurs in people who are either under-nourished or over-nourished. Undernutrition is a consequence of consuming too few essential nutrients or using or excreting them more rapidly than they can b…

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Mammals

The more than 4,000 species of living mammals belong to the vertebrate class Mammalia. This diverse group of animals has certain common features: all have four legs, bodies covered by hair, a high and constant body temperature, a muscular diaphragm used in respiration, a lower jaw consisting of a single bone, a left systemic aortic arch leaving the left ventricle of the heart, and three bones in t…

2 minute read

Manakins

Manakins are 53 species of small, tropical birds that comprise the family Pipridae, occurring from southern Mexico to Paraguay. Manakins are species that dwell in mature, tropical forests. Manakins are squat, compact birds, with short, rounded wings and a short tail. However, in some species the tail of the male is greatly lengthened by the occurrence of long, thin extensions, sometimes longer tha…

2 minute read

Mangrove Tree - Species Of Mangrove Trees, Ecology Of Mangrove Forest, Mangroves And Humans

Mangroves are trees in the family Rhizophoraceae, occurring in tropical and subtropical environments as swampy forests fringing muddy, tidal, estuarine, and oceanic shores. Mangrove forests are generally the first type of woody ecosystem that is encountered when a low-lying tropical shore is approached from the ocean. Mangrove forests comprise a biome, that is, a distinctive ecosystem that occurs …

1 minute read

Manic Depression - Diagnosis, Emil Kraepelin, Treatments For Manic-depressive Illness

Manic-depressive illness, clinically called bipolar disorder, is a major mental illness belonging to the category of illnesses designated as mood disorders. It is estimated that as many as two million Americans suffer from this illness and many more may go undiagnosed or underdiagnosed. Approximately one in five families will be confronted with a family member who may experience a manic episode or…

1 minute read

Manichaeism - Doctrine, Later History, Bibliography

Manichaeism arose in a highly cosmopolitan culture, in full awareness of antecedent west Asian religions such as Zoroastrianism, Christianity, and various pagan and Gnostic sects, as well as the Hindu, Jain, and Buddhist traditions of South Asia. According to Manichaean teaching, Mani was the last of a series of divinely inspired prophets that included Zoroaster, the Buddha, and Jesus Christ. Thes…

1 minute read

Maoism - Essential Features, Shaping Of Mao's Revolutionary Worldview, Development Of Mao's Thought To 1949

Maoism is not a term that is easy to define. While it is common sense that Maoism refers to the vision, ideology, and political viewpoint of Mao Zedong (1893–1976), it is difficult to pinpoint the specific contents and basic features of Mao's conceptual world in the context of the evolving course of the Chinese Communist revolution. Despite Mao's adoption of Marxist-Leninist t…

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Map

A map, or mapping, is a rule, often expressed as an equation, that specifies a particular element of one set for each element of another set. To help understand the notion of map, it is useful to picture the two sets schematically, and map one onto the other, by drawing connecting arrows from members of the first set to the appropriate members of the second set. For instance, let the set mapped fr…

3 minute read

Maps and the Ideas they Express - Preliterate And Early Literate Maps, Printed Maps Of A More Detailed Globe, Nineteenth Century: General And Thematic Mapping

Cartography, the art and science of mapmaking, began before the invention of writing and continues to be fundamental to an understanding of the phenomena it represents graphically. Although typically associated with Earth, or parts of this body, its methods are applicable to the delineation of both the microcosm and the macrocosm. Thus, there is mapping of the human brain on the one hand, and the …

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Marfan Syndrome

Marfan syndrome is genetic disease that involves defects in the connective tissues of the body with the cardinal collection of abnormalities affecting the skeletal, ocular, and cardiovascular systems. It is inherited as an autosomal dominant disorder, meaning that inheriting only one defective gene from either the paternal or maternal side will lead to the disorder. Although the majority of mutati…

4 minute read

Marijuana - History, Effects

Marijuana is the common name for the hemp plant Cannabis sativa. Hemp grows in tropical as well as temperate climates. The dried ground leaves, flowers, and stems of the plant have a long history for their use as drugs. It has been cultivated in different regions of the world throughout centuries for its fiber to produce linen, rope, canvas, and oil. It has also been used as a medicine to relieve …

1 minute read

Marmosets and Tamarins - Marmosets, Tamarins, The Odd Ones

Marmosets and tamarins are South and Central American primates of the Amazon Basin. Their family, Callitrichidae, includes 18 species that have been described as "near"-monkeys. All species are considered endangered or threatened by extinction. This plight is mostly caused by deforestation to develop new agricultural land, as well as disturbance of their forest habitat by logging, ro…

2 minute read

Marmots - North American Marmots, Marmots Elsewhere

Marmots are species of medium-sized robust, short-legged burrowing herbivorous rodents in the genus Marmota, family Sciuridae, order Rodentia. Marmots are closely related to the ground squirrels and gophers. Marmots live in burrows that they dig themselves, or sometimes in the deep crevices of rock piles and talus slopes beneath cliffs. Most species of marmots occur in alpine or arctic tundra or i…

2 minute read

Mars - The Red Planet, Physical Properties Of Mars, The History Of Mars, A Requiem For Percival Lowell

Mars is the fourth planet from the center of the solar system, orbiting the Sun once every 687 (Earth) days at a mean distance of 141 million mi (227 million km). Called the "red planet" for its distinct orange-red color, Mars has been the object of intense interest for over a century. Popularly regarded as a possible source of life, Mars was thought to be barren after the Viking spa…

1 minute read

Mars Pathfinder

The Mars Pathfinder probe landed on Mars on July 4, 1997. Pathfinder was second in the Discovery series of robotic spacecraft, which the United States National Aeronautics and Space Administration (NASA) began to develop in the mid 1990s. Costing an average of $150 million per project, the Discovery shift to faster, cheaper, less-ambitious probes was prompted by the catastrophic failure in 1993 of…

11 minute read

Marsupial Cats

Marsupial cats are native carnivores of Australia, in the family Dasyuridae. Like all marsupials, the young of marsupial cats are born when they are still in an embryonic state, and they migrate to a belly pouch (or marsupium) on the female, where they fix onto a nipple and suckle until they are almost fully grown and independent. Marsupial cats fill the ecological roles played by weasels, cats, f…

1 minute read

Marsupial Rats and Mice

Marsupial rats and mice are a diverse group of about 40 species of small, native carnivores of Australia, Tasmania, and New Guinea, in the family Dasyuridae. The young of marsupial rats and mice, as with those of all marsupials, are born while still in a tiny, embryonic stage of development. The almost helpless babies migrate to the belly of their mother, where they fix on a nipple and suckle unti…

1 minute read

Marsupials

Marsupials belong to the order Marsupalia, one of three subclasses of mammals (Metatheria). Marsupials are named for the marsupium, which means pouch in Latin; most female marsupials carry their young in pouches. The order Marsupalia includes eight families, 75 genera, and 250 species. Marsupials are divided into two groups based on the number and shape of the incisor teeth. One group has numerous…

3 minute read

Sable Marten and Fisher

Marten, sable, and fisher are species of medium-sized carnivores in the family Mustelidae, which also includes the weasels, otters, badgers, minks, skunks, and wolverine. Marten, sable, and fisher are generally solitary animals, living in forests of the Northern Hemisphere. All of these species have highly valuable fur, and are trapped intensively. The American pine marten (Martes americana) range…

2 minute read

Marxism - The Critical Project Of Karl Marx, Doctrinal Marxism, Doctrinal Marxism To 1914, After 1914: Leninism And Marxism-leninism

Few sets of ideas are richer and more conflicted than those that have been put forward under the heading of Marxism. Marxism's founder, the German philosopher Karl Marx (1818–1883), had a wide-ranging curiosity about many aspects of humankind and a stamina matching his curiosity. But as the American philosopher Sidney Hook pointed out in his article on Marxism in the 1973 edition of …

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Marxism in Asia - Japan, China, Vietnam And Southeast Asia, India, Conclusion, Bibliography

The writings of Karl Marx offer both a critique and a celebration of modern capitalism. On the one hand, Marx presented a devastating moral indictment of the capitalist exploitation of labor and the drowning of all human relationships in "the icy waters of egotistical calculation." On the other, Marx saw capitalism as a necessary and progressive phase of historical development, yield…

1 minute read

Maser

Maser is an acronym for microwave amplification by stimulated emission of radiation. Microwaves correspond to that portion of the electromagnetic spectrum where the radiation has wavelengths of 0.039-12 in (1 mm-30 cm), i.e., between the far infrared and radio frequencies. Crystals can be used as amplifiers of microwave radiation and as sources of radiation having a single wavelength and frequency…

1 minute read

Mass

Newton defined the mass of an object as the quantity of matter it possessed. A small rock, for example, has a mass—a fixed, unchanging quantity of matter. If you were to take that rock along with you on a trip to the moon, it would have the same quantity of matter (the same mass) that it had on Earth. Its weight, however, would be less on the moon. The rock's weight on earth was the …

3 minute read

Mass Extinction - Identifying Mass Extinctions, Greater And Lesser Mass Extinctions

Extinction, the death of all members of a species, is a natural process that has been occurring since the beginning of life on Earth. Nearly all species that have ever existed are now extinct, and extinction is an important process in the evolution of new species. Mass extinction, the death of large numbers of species over a relatively short span of geologic time, is also a natural process, but on…

1 minute read

Mass Number

The mass number of an atom is the total number of protons plus neutrons in its nucleus. To understand this situation, think of the binding energy as the strength of the "glue" that holds the protons and neutrons together as a nucleus. It is, therefore, the amount of energy that would be required to break the "glue" and pull the nucleus apart into its individual neutrons…

1 minute read

Mass Spectrometry

Mass spectrometry is an instrumental method of obtaining structure and mass information about either molecules or atoms by generating ionized particles and then accelerating them in a curved path through a magnetic field. Heavier particles are more difficult for the magnetic field to deflect around the curve, and thus travel in a straighter path than lighter particles. Consequently, by the time th…

2 minute read

Materialism in Eighteenth-Century European Thought - Seventeenth-century Background, The Eighteenth Century, French Materialism, English Materialism, Conclusion, Bibliography

Materialism is the generic name of a variety of doctrines that deny the existence of non-material substances. Materialism may be either a metaphysical or a methodological concept. In its most coherent and radical form, it is a type of monism, the metaphysical position stating that there is only one principle—matter and its properties—in terms of which all reality is to be explained. …

1 minute read

Mathematics

Mathematics, in the very broadest sense, is the systematic study of relationships in the physical world and relationships between symbols which need not pertain to the real world. In relation to the world, mathematics is the language of science. It operates within the laws and constraints of science as it examines physical phenomena. Unlike science, however, mathematics has no constraints. So in r…

4 minute read